Diagnostic device, work machine, and diagnostic system

Abstract

A diagnostic device includes a first processor for diagnosing an abnormality of a travel device on the basis of a travelling feature amount representing a travelling state of the travel device mounted to a machine body of a work machine and an output device for outputting a result of a diagnosis performed by the first processor. The first processor acquires an inclination feature amount representing an inclination state of the machine body, computes a correction amount for canceling an influence of the inclination state of the machine body on the travelling feature amount of the travel device on the basis of the inclination feature amount, computes a corrected travelling feature amount by correcting the travelling feature amount on the basis of the correction amount, computes an abnormality determination evaluation value on the basis of the corrected travelling feature amount, determines whether or not there is an abnormality in the travel device on the basis of the abnormality determination evaluation value, and outputs, when it is determined that there is an abnormality, relevant determination result to the output device.

Description

Technical Field

[0001] The present invention relates to a diagnostic device, a work machine provided with the diagnostic device, and a diagnostic system.Background Art

[0002] Patent Document 1 discloses a work machine provided with a controller for controlling the capacities of a first hydraulic pump and a second hydraulic pump according to an operation of a travelling operation device. The controller of the work machine calculates an abnormality determination evaluation value on the basis of a pressure difference between the pressure of the first hydraulic pump and the pressure of the second pump, and determines that there is an abnormality in either one of a left travel device and a right travel device on the basis of a comparison result between the abnormality determination evaluation value and a predetermined determination reference value.Prior Art DocumentPatent Documents

[0003] Patent Document 1: JP-2019-049102-ASummary of the InventionProblem to be Solved by the Invention

[0004] However, the pressure of the first hydraulic pump and the pressure of the second hydraulic pump used for determination of an abnormality are affected by the inclination of a travelling road surface. Therefore, in the invention described in Patent Document 1, there is a risk that an abnormality of the travel device is erroneously detected if the travelling road surface is inclined.

[0005] An object of the present invention is to prevent erroneous detection of an abnormality of a travel device when travelling on an inclined road surface and to appropriately detect an abnormality of the travel device.Means for Solving the Problem

[0006] A diagnostic device according to an aspect of the present invention includes: a first processor for diagnosing an abnormality of a travel device on the basis of a travelling feature amount representing a travelling state of the travel device mounted to a machine body of a work machine and an output device for outputting a result of a diagnosis performed by the first processor. The first processor is configured to: acquire an inclination feature amount representing an inclination state of the machine body; compute a correction amount for canceling an influence of the inclination state of the machine body on the travelling feature amount of the travel device on the basis of the inclination feature amount; compute a corrected travelling feature amount by correcting the travelling feature amount on the basis of the correction amount; compute an abnormality determination evaluation value on the basis of the corrected travelling feature amount; determine whether or not there is an abnormality in the travel device on the basis of the abnormality determination evaluation value, and output, when it is determined that there is an abnormality, relevant determination result to the output device.Advantages of the Invention

[0007] According to the present invention, it is possible to prevent erroneous detection of an abnormality of a travel device when travelling on an inclined road surface and to appropriately detect an abnormality of the travel device.Brief Description of the Drawings

[0008] [Fig. 1] Fig. 1 is a side view of a hydraulic excavator according to a first embodiment of the present invention. [Fig. 2] Fig. 2 is a perspective view of a lower track structure depicted in Fig. 1. [Fig. 3] Fig. 3 is an outline configuration diagram of a hydraulic drive system mounted on the hydraulic excavator depicted in Fig. 1. [Fig. 4] Fig. 4 is a diagram for depicting a travel drive system of the hydraulic excavator. [Fig. 5] Fig. 5 is a diagram for depicting a machine body coordinate system of the hydraulic excavator and a rotation angle of the hydraulic excavator (lower track structure). [Fig. 6] Fig. 6 is a schematic rear view of the hydraulic excavator and depicts a case where a travelling road surface is a horizontal road surface parallel to the horizontal direction. [Fig. 7] Fig. 7 is a schematic rear view of the hydraulic excavator and depicts a case where a travelling road surface is an inclined road surface inclined with respect to the horizontal direction. [Fig. 8] Fig. 8 is a diagram for depicting characteristics of a roll angle φ and loads FL and FR applied to left and right travel devices, respectively. [Fig. 9] Fig. 9 is a rear view of the hydraulic excavator and is a diagram for depicting an attachment position of an inclination angle sensing device. [Fig. 10] Fig. 10 is a functional block diagram of a controller according to the first embodiment. [Fig. 11] Fig. 11 is a diagram for explaining details of correction logic by a differential pressure value calculation section and a correction amount calculation section. [Fig. 12] Fig. 12 is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller according to the first embodiment. [Fig. 13] Fig. 13 is a functional block diagram of a controller according to a second embodiment. [Fig. 14] Fig. 14 is a diagram for depicting an allowable load difference and an allowable roll angle range. [Fig. 15] Fig. 15 is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller according to the second embodiment. [Fig. 16] Fig. 16 is a schematic view for depicting inclination angles (a roll angle φtrv and a pitch angle θtrv) of the lower track structure and inclination angles (a roll angle φswg and a pitch angle θswg) of an upper swing structure. [Fig. 17] Fig. 17 depicts graphs for depicting the relationship between a swing angle ψ and the roll angle φtrv of the lower track structure and the relationship between the swing angle ψ and the pitch angle θtrv of the lower track structure when the roll angle φswg of the upper swing structure is 10°. [Fig. 18] Fig. 18 is a functional block diagram of a controller according to a third embodiment. [Fig. 19] Fig. 19 is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller according to the third embodiment. [Fig. 20] Fig. 20 is a diagram for depicting a configuration of a diagnostic system according to a fourth embodiment. [Fig. 21] Fig. 21 is a functional block diagram of the diagnostic system according to the fourth embodiment. [Fig. 22] Fig. 22 is a conceptual diagram for calculating data by down-sampling after applying a filter for feature extraction. [Fig. 23] Fig. 23 is a flowchart for depicting an example of the flow of abnormality determination processing executed by a controller according to a modified example 1. [Fig. 24] Fig. 24 is a flowchart for depicting an example of the flow of abnormality determination processing executed by a controller according to a modified example 2. Modes for Carrying Out the Invention

[0009] Hereinafter, a hydraulic work machine according to embodiments of the present invention will be described with reference to the drawings by taking a hydraulic excavator as an example. It should be noted that in the drawings, the same reference numerals are given to equivalent members, and redundant descriptions are appropriately omitted.<First Embodiment>

[0010] Fig. 1 is a side view of a hydraulic excavator 100 according to a first embodiment of the present invention.

[0011] As depicted in Fig. 1, the hydraulic excavator 100 is provided with a lower track structure 101, an upper swing structure 102 swingably provided with respect to the lower track structure 101, and a work device 103 attached to the front side of the upper swing structure 102. The lower track structure 101 and the upper swing structure 102 configure a machine body 107 of the hydraulic excavator 100.

[0012] The work device 103 is provided with a boom 104 attached to a right front portion of the upper swing structure 102 so as to be rotatable in the vertical direction, an arm 105 attached to a tip end portion of the boom 104 so as to be rotatable in the vertical and longitudinal directions, a bucket 106 attached to a tip end portion of the arm 105 so as to be rotatable in the vertical and longitudinal directions, a boom cylinder 33 as a hydraulic actuator for driving the boom 104, an arm cylinder 34 as a hydraulic actuator for driving the arm 105, and a bucket cylinder 35 as a hydraulic actuator for driving the bucket 106.

[0013] An operation room 110 is provided at a left front portion of the upper swing structure 102. In the operation room 110, left and right travelling lever devices 6 and 7 (see Fig. 4) as travelling operation devices for operating the lower track structure 101, left and right operation lever devices 8 and 9 (see Fig. 4) as work operation devices for operating the upper swing structure 102 and the work device 103, and the like are arranged.

[0014] An enclosure (engine room) in which hydraulic equipment such as a first hydraulic pump 11 and a second hydraulic pump 21 (see Fig. 3) and an engine 1 (see Fig. 3) are mounted is provided behind the operation room 110.

[0015] As depicted in Fig. 4, the left travelling lever device 6 has a left travelling lever 6a for operating a left travelling motor 31. The right travelling lever device 7 has a right travelling lever 7a for operating a right travelling motor 32. The left operation lever device 8 has a left operation lever 8a for operating the arm cylinder 34 and a swing motor 36 (see Fig. 3). The right operation lever device 9 has a right operation lever 9a for operating the boom cylinder 33 and the bucket cylinder 35.

[0016] Fig. 2 is a perspective view of the lower track structure 101 depicted in Fig. 1.

[0017] As depicted in Fig. 2, the lower track structure 101 is provided with a track frame 41 and left and right travel devices 50 and 60 provided on the left and right sides of the track frame 41, respectively. The left and right travel devices 50 and 60 are provided with left and right travel drive systems 51 and 61, left and right crawlers (track links and shoes) 52 and 62 driven by the left and right travel drive systems 51 and 61, left and right front idlers 53 and 63 for supporting the left and right crawlers 52 and 62, and left and right vertical rollers (not depicted), respectively.

[0018] The left travel drive system 51 is provided with the left travelling motor 31 (see Fig. 3) including a hydraulic motor, a travelling reduction gear 54 (see Fig. 3) for reducing the rotation of the left travelling motor 31 and transmitting the reduced rotation to the crawler, and a brake valve 55 (see Fig. 4) for braking the left travelling motor 31. Similarly, the right travel drive system 61 is provided with the right travelling motor 32 (see Fig. 3) including a hydraulic motor, a travelling reduction gear 64 (see Fig. 3) for reducing the rotation of the right travelling motor 32 and transmitting the reduced rotation to the crawler, and a brake valve 65 (see Fig. 4) for braking the right travelling motor 32.

[0019] A swing ring 42 for swingably coupling the upper swing structure 102 is provided at an upper portion of the track frame 41. A center joint 43 for circulating hydraulic fluid between the lower track structure 101 and the upper swing structure 102 is arranged at the center position of the swing ring 42. The left and right travel drive systems 51 and 61 and the center joint 43 are connected to each other by pipes 44.

[0020] Fig. 3 is an outline configuration diagram of a hydraulic drive system 200 mounted on the hydraulic excavator 100 depicted in Fig. 1.

[0021] As depicted in Fig. 3, the hydraulic drive system 200 is provided with the engine 1 as a prime mover, the first hydraulic pump 11 driven by the engine 1, the second hydraulic pump 21 driven by the engine 1, a first control valve unit 12 for controlling the flow of hydraulic operating fluid supplied from the first hydraulic pump 11 to a plurality of hydraulic actuators (the left travelling motor 31, the arm cylinder 34, the swing motor 36, and an actuator for attachment 37) including the left travelling motor 31, and a second control valve unit 22 for controlling the flow of hydraulic operating fluid supplied from the second hydraulic pump 21 to a plurality of hydraulic actuators (the right travelling motor 32, the boom cylinder 33, and the bucket cylinder 35) including the right travelling motor 32.

[0022] The first control valve unit 12 and the second control valve unit 22 are multiple directional control valves each having a plurality of directional control valves. The first control valve unit 12 has a directional control valve for left travelling 12a that controls the flow of hydraulic fluid between the first hydraulic pump 11 and the left travelling motor 31. The second control valve unit 22 has a directional control valve for right travelling 22a that controls the flow of hydraulic fluid between the second hydraulic pump 21 and the right travelling motor 32.

[0023] Fig. 4 is a diagram for depicting a travel drive system of the hydraulic excavator 100.

[0024] As depicted in Fig. 4, the travel drive system of the travel device of the left (hereinafter, also referred to as a left travel device) 50 is provided with the left travelling motor 31 driven by hydraulic fluid supplied from the first hydraulic pump 11, the directional control valve for left travelling 12a for controlling the flow of the hydraulic fluid supplied from the first hydraulic pump 11 to the left travelling motor 31, and the left brake valve 55 provided in a hydraulic line connecting the directional control valve for left travelling 12a and the left travelling motor 31 to each other. The travel drive system of the travel device of the right (hereinafter, also referred to as a right travel device) 60 is provided with the right travelling motor 32 driven by hydraulic fluid supplied from the second hydraulic pump 21, the directional control valve for right travelling 22a for controlling the flow of the hydraulic fluid supplied from the second hydraulic pump 21 to the right travelling motor 32, and the right brake valve 65 provided in a hydraulic line connecting the directional control valve for right travelling 22a and the right travelling motor 32 to each other.

[0025] The first hydraulic pump 11 and the second hydraulic pump 21 are variable displacement hydraulic pumps. The first hydraulic pump 11 is provided with a pump regulator 11a for adjusting the delivery capacity (displacement volume per one revolution) of the first hydraulic pump 11. The second hydraulic pump 21 is provided with a pump regulator 21a for adjusting the delivery capacity (displacement volume per one revolution) of the second hydraulic pump 21.

[0026] The hydraulic excavator 100 is provided with a first pressure sensor 13, a second pressure sensor 23, a work operation sensor 3, a swing operation sensor 4, a travelling operation sensor 5, and a controller 2. The first pressure sensor 13 is provided in a hydraulic line connecting the first hydraulic pump 11 and the first control valve unit 12 to each other. The first pressure sensor 13 senses a first pump pressure P1 that is the delivery pressure of the first hydraulic pump 11, and outputs a signal (sensor value) representing the sensed result to the controller 2. The second pressure sensor 23 is provided in a hydraulic line connecting the second hydraulic pump 21 and the second control valve unit 22 to each other. The second pressure sensor 23 senses a second pump pressure P2 that is the delivery pressure of the second hydraulic pump 21, and outputs a signal (sensor value) representing the sensed result to the controller 2. The first pump pressure P1 is a travelling state amount representing the travelling state (travel driving force) of the left travel device 50, and the second pump pressure P2 is a travelling state amount representing the travelling state (travel driving force) of the right travel device 60. Therefore, the first pressure sensor 13 and the second pressure sensor 23 function as travelling state sensors for sensing the travelling states of the travel devices 50 and 60.

[0027] The work operation sensor 3 senses operations (work operations) of the boom cylinder 33, the arm cylinder 34, and the bucket cylinder 35 operated by an operator, and outputs work operation signals representing the sensed results to the controller 2. The swing operation sensor 4 senses an operation (swing operation) of the swing motor 36 operated by the operator and outputs a swing operation signal representing the sensed result to the controller 2. The travelling operation sensor 5 senses operations (travelling operations) of the left and right travelling motors 31 and 32 operated by the operator, and outputs travelling operation signals representing the sensed results to the controller 2.

[0028] The controller 2 is configured with a computer provided with a processor 2a such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or a DSP (Digital Signal Processor), a non-volatile memory 2b such as a ROM (Read Only Memory), a flash memory, or a hard disk drive, a volatile memory 2c what is called a RAM (Random Access Memory), an input interface 2d, an output interface 2e, and other peripheral circuits. These pieces of hardware cooperate with each other to operate software and realize a plurality of functions. It should be noted that the controller 2 may be configured with one computer or a plurality of computers. In addition, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), or the like can be used as the processor 2a.

[0029] The non-volatile memory 2b stores programs capable of executing various computations. That is, the non-volatile memory 2b is a storage medium (storage device) capable of reading programs for realizing the functions of the present embodiment. The volatile memory 2c is a storage medium (storage device) for temporarily storing a computation result computed by the processor 2a and a signal input from the input interface 2d. The processor 2a is a device for expanding the program stored in the non-volatile memory 2b into the volatile memory 2c to execute a computation, and performs predetermined computation processing on data taken in from the input interface 2d, the non-volatile memory 2b, and the volatile memory 2c in accordance with the program.

[0030] The input interface 2d converts signals input from various devices (the pressure sensors 13 and 23, the operation sensors 3, 4, and 5, and the like) into data that can be computed by the processor 2a. In addition, the output interface 2e generates an output signal according to the computation result of the processor 2a, and outputs the signal to various devices (the pump regulators 11a and 21a and the like).

[0031] The controller 2 calculates target delivery flow rates of the first hydraulic pump 11 and the second hydraulic pump 21 on the basis of the sensed results of the work operation sensor 3, the swing operation sensor 4, and the travelling operation sensor 5. The controller 2 calculates target capacities (target delivery capacities) of the first hydraulic pump 11 and the second hydraulic pump 21 on the basis of the calculated target delivery flow rates, and outputs command signals according to the calculated target capacities to the pump regulators 11a and 21a. Accordingly, the delivery flow rates of the first hydraulic pump 11 and the second hydraulic pump 21 are controlled so as to coincide with the respective target delivery flow rates. For example, the controller 2 increases the target capacity of the first hydraulic pump 11 as the operation amount of the left travelling lever device 6 increases. In addition, for example, the controller 2 increases the target capacity of the second hydraulic pump 21 as the operation amount of the right travelling lever device 7 increases.

[0032] In the present embodiment, a diagnostic device 80 for diagnosing an abnormality of the travel devices 50 and 60 is mounted on the hydraulic excavator 100. The diagnostic device 80 includes the controller 2 and an output device (a display device 91 and a communication device 92) mounted on the hydraulic excavator 100. The controller 2 diagnoses an abnormality of the left and right travel devices 50 and 60 when the hydraulic excavator 100 is in a predetermined operation state on the basis of the operation amounts sensed by the operation sensors 3 to 5, the first pump pressure P1 sensed by the first pressure sensor 13, and the second pump pressure P2 sensed by the second pressure sensor 23. The result of the diagnosis is output by the display device 91 and the communication device 92 as the output device.

[0033] Incidentally, the first pump pressure P1 and the second pump pressure P2 used for the abnormality diagnosis are affected by the inclination of a travelling road surface. Hereinafter, the causes that affect the first pump pressure P1 and the second pump pressure P2 on a slope will be described.

[0034] Fig. 5 is a diagram for depicting a machine body coordinate system of the hydraulic excavator 100 and a rotation angle of the hydraulic excavator 100 (lower track structure 101).

[0035] As depicted in Fig. 5, for example, the machine body coordinate system that is a coordinate system using the lower track structure 101 as a reference is set to the hydraulic excavator 100. The machine body coordinate system is defined as a right-handed coordinate system using as the origin an arbitrary point on the swing centerline that is the rotation axis of the upper swing structure 102. In the machine body coordinate system, the forward direction of the lower track structure 101 is defined as the positive direction of the X axis. In the machine body coordinate system, the vertically upper direction along the swing centerline is defined as the positive direction of the Z axis. In the machine body coordinate system, the left direction of the lower track structure 101 orthogonal to each of the X axis and the Z axis is defined as the positive direction of the Y axis.

[0036] Rotation in the X-Z plane orthogonal to the Y axis is called pitching, and the rotation angle thereof is represented by a pitch angle θ. Rotation in the X-Y plane orthogonal to the Z axis is called yawing, and the rotation angle thereof is represented by a yaw angle ψ. Rotation in the Y-Z plane orthogonal to the X axis is called rolling, and the rotation angle thereof is represented by a roll angle φ. The X axis is an axis along the advancing direction of the lower track structure 101, and the roll angle φ with the X-axis as the rotation axis corresponds to the lateral inclination angle of the lower track structure 101 with respect to a horizontal plane. Here, the horizontal plane means a virtual plane orthogonal to the gravity direction (vertical direction).

[0037] Fig. 6 and Fig. 7 are schematic rear views of the hydraulic excavator 100. In the drawings, loads acting on the hydraulic excavator 100 are schematically indicated by arrows. Fig. 6 depicts a case where a travelling road surface 109 is a horizontal road surface 109a parallel to the horizontal direction, and Fig. 7 depicts a case where the travelling road surface 109 is an inclined road surface 109b inclined with respect to the horizontal direction. The horizontal direction is the direction orthogonal to the direction of gravity (vertical direction). That is, the roll angle φ is 0° (φ = 0).

[0038] As depicted in Fig. 6, where the hydraulic excavator 100 travels on the horizontal road surface 109a, a load (reaction force) equally acts on each of the left travel device 50 and the right travel device 60 from the ground. That is, a load FL acting on the left travel device 50 is equal to a load FR acting on the right travel device 60. In addition, the loads FL and FR acting on the travel device 50 are half of the deadweight F of the hydraulic excavator 100 (FL = FR = 1 / 2 × F). As depicted in Fig. 6, the posture of the hydraulic excavator 100 when the hydraulic excavator 100 is not inclined is referred to as a horizontal posture. In addition, an intersection point between the swing center axis of the hydraulic excavator 100 in the horizontal posture and the travelling road surface 109 is defined as a reference point O.

[0039] As depicted in Fig. 7, where the hydraulic excavator 100 travels on the inclined road surface 109b in a state of being inclined to the left and right, the load (reaction force) received by the left travel device 50 from the ground and the load (reaction force) received by the right travel device 60 from the ground are different from each other in magnitude (FL ≠ FR). The load acting on the hydraulic excavator 100 will be specifically described with reference to Fig. 7.

[0040] The roll angle (φ of the lower track structure 101 travelling on the inclined road surface 109b is not 0° (φ ≠ 0). In the illustrated example, the left travel device 50 is positioned on the lower side than the right travel device 60. That is, the height of the left travel device 50 is lower than the height of the right travel device 60. Here, the height means a distance in the vertical direction from the horizontal reference plane to the travel device 50 or 60. In addition, as depicted in Fig. 7, the posture of the hydraulic excavator 100 when the hydraulic excavator 100 is inclined to the left or right is referred to as an inclined posture.

[0041] In the horizontal posture depicted in Fig. 6, the centroid position G of the hydraulic excavator 100 is positioned near the centerline of the hydraulic excavator 100 in the lateral width direction. In the inclined posture depicted in Fig. 7, the centroid position G of the hydraulic excavator 100 moves toward the left travel device 50 having a relatively low height between the left and right travel devices 50 and 60 as compared with the horizontal posture (see Fig. 6). Specifically, the centroid position G is positioned on the left side relative to the reference point O. As a result, the load FL acting on the left travel device 50 is larger than the load FR acting on the right travel device 60.

[0042] The load FR acting on the right travel device 60 is calculated by the following equation (1). The load FL acting on the left travel device 50 is calculated by the following equation (2). FR = 1 / 2 − h / B × tanφ × F FL = 1 / 2 + h / B × tanφ × F

[0043] F is the gravity acting on the hydraulic excavator 100. The roll angle φ is the inclination angle of the travelling road surface 109 from the horizontal plane (reference plane). B is the distance from the center of the crawler of the left travel device 50 to the center of the crawler of the right travel device 60, and is hereinafter referred to as a crawler width. In each equation, h is the height from the travelling road surface 109 to the centroid position G (h > 0). That is, the height h corresponds to the distance from the centroid position G to the travelling road surface 109 in a perpendicular line from the centroid position G to the travelling road surface 109.

[0044] The crawler width B, the height h, and the roll angle φ satisfy the following equation (3). − B / 2 h ≤ tanφ ≤ B / 2 h

[0045] Where the travelling road surface 109 is inclined, the load acting on the travel device positioned at a higher position becomes smaller as compared with when the travelling road surface 109 is horizontal. Conversely, the load acting on the travel device positioned at a lower position becomes larger.

[0046] Fig. 8 is a diagram for depicting characteristics of the roll angle φ and the loads FL and FR applied to the left and right travel devices 50 and 60, respectively.

[0047] As depicted in Fig. 8, when the hydraulic excavator 100 is in the horizontal posture, the roll angle φ is 0°. When the hydraulic excavator 100 is in the inclined posture in which the left travel device 50 is positioned on the lower side and the right travel device 60 is positioned on the upper side, the roll angle φ has a positive value. When the hydraulic excavator 100 is in the inclined posture in which the right travel device 60 is positioned on the lower side and the left travel device 50 is positioned on the upper side, the roll angle φ has a negative value. As the roll angle φ becomes larger from 0°, the load FL acting on the left travel device 50 becomes larger and the load FR acting on the right travel device 60 becomes smaller. Conversely, as the roll angle becomes smaller from 0° (becomes larger in the negative direction), the load FR acting on the right travel device 60 becomes larger and the load FL acting on the left travel device 50 becomes smaller.

[0048] Where the hydraulic excavator 100 travels in the inclined posture, the loads acting on the left and right travel devices 50 and 60 change from those in the horizontal posture as described above. Accordingly, the loads acting on driving portions, sliding portions, and the like configuring the travel drive systems 51 and 61 change from those in the horizontal posture. In the inclined posture, frictional force and travelling resistance (loss force) with respect to the ground change from those in the horizontal posture, and the driving force necessary for travel driving of the hydraulic excavator 100 changes. For example, in the inclined posture in which the left travel device 50 is positioned at a positioned lower than the right travel device 60, the amount of the left travel device 50 sinking into the ground becomes larger than that in the horizontal posture. As a result, the road surface resistance acting on the left travel device 50 from the ground becomes larger than that in the horizontal posture. That is, the driving force necessary for travel driving of the left travel device 50 in the inclined posture becomes larger compared with that in the horizontal posture. As a result, the driving pressure of the left travelling motor 31 (the delivery pressure of the first hydraulic pump 11) becomes larger compared with that in the horizontal posture.

[0049] As described above, there is a case where the driving force necessary for travel driving changes due to a change in the loads acting on the left and right travel devices 50 and 60. Therefore, in the present embodiment, in order to appropriately diagnose an abnormality of the travel devices 50 and 60, parameters used for abnormality diagnosis are corrected according to the inclination state of the machine body 107.

[0050] Fig. 9 is a rear view of the hydraulic excavator 100 and is a diagram for depicting an attachment position of an inclination angle sensor 76.

[0051] In the present embodiment, the inclination angle sensor 76 is attached to the track frame 41 of the lower track structure 101 as depicted in Fig. 9 in order to grasp the inclination state of the machine body 107. The inclination angle sensor 76 senses the roll angle φ that is the lateral inclination angle of the lower track structure 101 with respect to the horizontal plane, and outputs a signal (sensor value) representing the sensed result to the controller 2. The controller 2 can grasp the inclination state (rolled state) of the hydraulic excavator 100 on the basis of the sensed result of the inclination angle sensor 76. The inclination angle sensor 76 can employ an IMU (Inertial Measurement Unit) that acquires angular velocities and accelerations of orthogonal three axes as information related to the posture of the lower track structure 101, computes the roll angle φ of the lower track structure 101 on the basis of this information, and outputs a signal representing the roll angle φ to the controller 2. The roll angle φ is an inclination state amount representing the inclination state of the machine body 107 with respect to the horizontal plane. Therefore, the inclination angle sensor 76 functions as an inclination state sensor for sensing the inclination state of the machine body 107 with respect to the horizontal plane.

[0052] Fig. 10 is a functional block diagram of the controller 2.

[0053] The display device 91 such as a liquid crystal monitor installed in the operation room 110, and the communication device 92 installed in an outer frame or the like of the operation room 110 are connected to the controller 2. The display device 91 is an output device that is controlled by the controller 2 and outputs the computation result of the controller 2 as an image. The communication device 92 is a wireless communication device capable of wirelessly communicating with a wireless base station connected to a communication line, and has a communication interface including a communication antenna using a band such as a 2.1 GHz band as a sensitive band. The communication device 92 exchanges information with a server 40 or the like via a communication line. The communication device 92 is an output device that is controlled by the controller 2 and outputs communication data representing the computation result of the controller 2. The server 40 is installed in, for example, a management facility apart from the work site of the hydraulic excavator 100. A vehicle manager and a service person can manage various vehicles that conduct work at the work site on the basis of operation information of the various vehicles (the hydraulic excavator and the like) displayed on a display device such as a liquid crystal monitor connected to the server 40.

[0054] The controller 2 is provided with a differential pressure value calculation section 81, an effective differential pressure value extraction section 82, a correction amount calculation section 83, a state determination section 70, and an abnormality determination section 90. The processor 2a of the controller 2 realizes these functions by executing the programs stored in the non-volatile memory 2b. The state determination section 70 determines whether or not a travelling single operation is being performed on the basis of the travelling operation signal from the travelling operation sensor 5, the work operation signal from the work operation sensor 3, and the swing operation signal from the swing operation sensor 4.

[0055] The state determination section 70 determines whether or not the hydraulic excavator 100 is travelling straight ahead on the basis of a first tilting command value that is a tilting command value of the first hydraulic pump 11 and a second tilting command value that is a tilting command value of the second hydraulic pump 21. When the difference between the first tilting command value and the second tilting command value is equal to or smaller than a volume difference threshold value, the state determination section 70 determines that the hydraulic excavator 100 is travelling straight ahead. When the difference between the first tilting command value and the second tilting command value is larger than the volume difference threshold value, the state determination section 70 determines that the hydraulic excavator 100 is not travelling straight ahead.

[0056] The first tilting command value and the second tilting command value are calculated on the basis of the travelling operation signal from the travelling operation sensor 5, the work operation signal from the work operation sensor 3, and the swing operation signal from the swing operation sensor 4. For example, the first hydraulic pump 11 and the second hydraulic pump 21 are controlled so as to increase in volume as the operation amounts of the left and right travelling levers 6a and 7a and the left and right operation levers 8a and 9a increase. Such control is called positive control. It should be noted that the method of controlling the hydraulic pumps 11 and 21 is not limited to this.

[0057] The state determination section 70 determines whether or not the hydraulic excavator 100 is during the travelling single operation and is travelling straight ahead. Where the state determination section 70 determines that the hydraulic excavator 100 is during the travelling single operation and is travelling straight ahead, it is assumed that diagnostic conditions are satisfied and a valid mode is set to validate a parameter used for abnormality diagnosis. Where the state determination section 70 determines that the hydraulic excavator 100 is during neither the travelling single operation nor the travelling in straight ahead, it is assumed that the diagnostic conditions are not satisfied and an invalid mode is set to invalidate the parameter used for abnormality diagnosis. It should be noted that in the present embodiment, the method of calculating a corrected differential pressure value ΔPc that is a parameter (abnormality determination evaluation value) used for abnormality diagnosis will be described later.

[0058] The differential pressure value calculation section 81 calculates a differential pressure value ΔP obtained by subtracting the second pump pressure (pressure value) P2 sensed by the second pressure sensor 23 from the first pump pressure (pressure value) P1 sensed by the first pressure sensor 13 (ΔP = P1 - P2). In this manner, the differential pressure value calculation section 81 calculates the differential pressure value ΔP as travelling feature amounts of the travel devices 50 and 60 on the basis of the sensor values representing the travelling state sensed by the first pressure sensor 13 and the second pressure sensor 23. The differential pressure value calculation section 81 corrects the differential pressure value ΔP by a correction amount Pc calculated by the correction amount calculation section 83 and calculates the corrected differential pressure value ΔPc that is the differential pressure value after correction. That is, the differential pressure value calculation section 81 calculates the corrected differential pressure value ΔPc as a corrected travelling feature amount by correcting the travelling feature amount (differential pressure value ΔP) on the basis of the correction amount Pc.

[0059] The correction amount calculation section 83 calculates the roll angle φ as an inclination feature amount on the basis of the sensor value representing the inclination angle (inclination state) sensed by the inclination angle sensor 76. In addition, the correction amount calculation section 83 calculates the correction amount Pc on the basis of correction amount parameters (a loss torque coefficient C and a load characteristic table T to be described later) stored in advance in the non-volatile memory 2b and the roll angle φ. The method of calculating the correction amount Pc by the correction amount calculation section 83 will be described later.

[0060] Where the valid mode is set by the state determination section 70 (where the hydraulic excavator 100 is during the travelling single operation and is travelling straight ahead), the effective differential pressure value extraction section 82 extracts the corrected differential pressure value ΔPc from the differential pressure value calculation section 81 as the abnormality determination evaluation value, and outputs it to the abnormality determination section 90. Where the invalid mode is set by the state determination section 70 (where the hydraulic excavator 100 is not during the travelling single operation or where the hydraulic excavator 100 is not travelling straight ahead), the effective differential pressure value extraction section 82 sets the abnormality determination evaluation value as 0 (zero) and outputs it to the abnormality determination section 90.

[0061] The abnormality determination section 90 determines whether or not there is an abnormality in either one of the left travel device 50 and the right travel device 60 on the basis of the comparison result between the abnormality determination evaluation value (the corrected differential pressure value ΔPc in the valid mode) from the effective differential pressure value extraction section 82 and a determination reference value ΔP0. Here, the determination reference value ΔP0 is a value that is empirically obtained and is stored in advance in the non-volatile memory 2b. It should be noted that it is preferable that the controller 2 is configured to be capable of changing the determination reference value ΔP0 on the basis of an operation performed by the operator or the like on the input device.

[0062] The abnormality determination section 90 outputs the determination result to the display device 91 and the communication device 92. The display device 91 displays an image representing the determination result of the abnormality determination section 90 on the screen. The communication device 92 transmits the determination result of the abnormality determination section 90 to the server 40. The display device, a printing device, and the like are connected to the server 40. The server 40 outputs the received determination result to the display device or the printing device connected to the server 40. Accordingly, the operator, the vehicle manager, and the service person can quickly grasp an abnormality of the travel devices 50 and 60 of the hydraulic excavator 100.

[0063] Next, a method of calculating the correction amounts Pc1 and Pc2 of the differential pressure value ΔP in consideration of the inclination state of the travelling road surface 109 will be described. First, the relationship between the pump pressure and the travel driving force will be described. In order to establish the conditions of the abnormality diagnosis of the travel devices 50 and 60, it is necessary that the hydraulic excavator 100 is travelling straight ahead. During travelling straight ahead, a pump pressure acts on the travelling motors 31 and 32 as a driving pressure. Thus, the travel driving force by the pump pressure is generated in the travelling motors 31 and 32.

[0064] A left travel driving force TmotL that is the travel driving force by the left travelling motor 31 and a right travel driving force TmotR that is the travel driving force by the right travelling motor 32 are represented by the following equations (4) and (5), respectively. TmotL = P 1 × q 1 / 2 Π × Ratio TmotR = P 2 × q 2 / 2 Π × Ratio

[0065] Here, P1 is the delivery pressure (first pump pressure) of the first hydraulic pump 11, and P2 is the delivery pressure (second pump pressure) of the second hydraulic pump 21. In the equations, q1 is the displacement volume of the left travelling motor 31, and q2 is the displacement volume of the right travelling motor 32. Ratio is a reduction ratio between the travelling reduction gears 54 and 64 of the travelling motors 31 and 32. During travelling straight ahead, the displacement volume q1 of the left travelling motor 31 is equal to the displacement volume q2 of the right travelling motor 32. Therefore, the displacement volume q1 of the left travelling motor 31 and the displacement volume q2 of the right travelling motor 32 are also hereinafter referred to as a motor volume q (q = q1 = q2).

[0066] The driving force of the left travelling reduction gear 54 is represented by the following equation (6), and the driving force of the right travelling reduction gear 64 is represented by the following equation (7). TmotL = P 1 × q / 2 Π × Ratio = TtrvL + TlossL TmotR = P 2 × q / 2 Π × Ratio = TtrvR + TlossR

[0067] Here, TtrvL is a torque (left travel driving effective torque) effectively used for travel driving in the left travelling motor 31, and TtrvR is a torque (right travel driving effective torque) effectively used for travel driving in the right travelling motor 32. TlossL is a loss torque such as a drag resistance force at the time of the travelling operation in the left travelling motor 31, and is hereinafter referred to as a left loss torque. TlossR is a loss torque such as a drag resistance force at the time of the travelling operation in the right travelling motor 32, and is hereinafter referred to as a right loss torque.

[0068] When the hydraulic excavator 100 is travelling straight ahead in the horizontal posture, the left loss torque and the right loss torque are substantially equal to each other (TlossL ≈ TlossR). Therefore, an effective torque difference ΔT that is the difference between the left travel driving force and the right travel driving force is represented by the following equation (8) according to the equations (6) and (7). ΔT = TtrvL − TtrvR = q / 2 Π × Ratio × P 1 − P 2

[0069] According to the equation (8), it is understood that the effective torque difference ΔT at the time of the travel driving can be grasped from the differential pressure value ΔP (= P1 - P2) between the first pump pressure P1 and the second pump pressure P2.

[0070] However, when the hydraulic excavator 100 is travelling straight ahead in the inclined posture, a case where the loss torques TlossL and TlossR acting on the travel devices 50 and 60 are largely different from each other is also assumed. Therefore, where the equation (7) is subtracted from the equation (6) when the hydraulic excavator 100 is travelling straight ahead in the inclined posture, the left loss torque TlossL and the right loss torque TlossR remain without being canceled as represented by the following equation (9).

[0071] Therefore, in order to perform abnormality diagnosis by the differential pressure value ΔP, it is necessary to perform correction in consideration of the loss torques TlossL and TlossR.

[0072] Next, a method of correction will be described in detail. As described above, in a state where the machine body 107 is inclined to the left and right, the loads acting on the left and right travel devices 50 and 60 are different from each other as depicted in Fig. 8. Where the loss torque at the time of the travel driving is assumed to be a force (loss torque) according to a load such as a friction force, an estimated value of the left loss torque (hereinafter, a left loss torque estimated value) TlossL_est and an estimated value of the right loss torque (hereinafter, a right loss torque estimated value) TlossR_est are represented by the following equations (10) and (11), respectively. TlossL_est = C 1 × FL TlossR_est = C 2 × FR

[0073] Here, FL is the load applied to the left travel device 50 and FR is the load applied to the right travel device 60. C1 is the loss torque coefficient (corresponding to a friction coefficient) of the left travel device 50, and C2 is the loss torque coefficient (corresponding to a friction coefficient) of the right travel device 60. The loss torque coefficients C1 and C2 may be basically considered to be substantially equivalent to each other because the left and right travel devices 50 and 60 have equivalent configurations. Therefore, the loss torque coefficients C1 and C2 are also hereinafter referred to as a loss torque coefficient C (C = C1 = C2). The loss torque coefficients C1 and C2 are set from design values, past measurement data, knowledge, and the like, and are stored in advance in the non-volatile memory 2b.

[0074] The controller 2 corrects the differential pressure value ΔP so as to suppress (cancel) the influence (the difference between the left loss torque TlossL and the right loss torque TlossR)) of the inclination state by correcting the amount of change in the differential pressure value ΔP due to inclination.

[0075] Specifically, as depicted in an equation (12), the influence of the inclination state can be canceled by subtracting (TlossL - TlossR) on the right side of the equation (9) by (TlossL_est - TlossR_est). q / 2 π + Ratio × P 1 − P 2 = TtrvL + TlossL − TlossL _ est − TtrvR + TlossR − TlossR _ est

[0076] Here, if the loss torque estimated values TlossL_est and TlossR_est have less error with respect to the loss torques TlossL and TlossR, the following equation (13) is obtained. q / 2 π × Ratio × P 1 − P 2 = TtrvL − TtrvR

[0077] When the equation (13) is arranged in units of pressure, an equation (14) is obtained. P 1 − P 2 = 2 π / q × Ratio × TtrvL − TtrvR

[0078] According to this, even where the travelling loss torques change due to the difference between the loads acting on the travel devices 50 and 60 in the inclined posture, the effective driving force difference excluding the influence of the inclination state can be grasped by sensing the inclination state, estimating the loss torques from the acting loads, and correcting the differential pressure value on the basis of the estimation result.

[0079] Fig. 11 is a diagram for explaining details of correction logic by the differential pressure value calculation section 81 and the correction amount calculation section 83.

[0080] As depicted in Fig. 11, the correction amount calculation section 83 refers to the load characteristic table T and computes the load FL acting on the left travel device 50 and the load FR acting on the right travel device 60 on the basis of the roll angle φ of the lower track structure 101 sensed by the inclination angle sensor 76. The load characteristic table T is a data table for defining the relationship between the roll angle φ and the loads FL and FR described by using Fig. 8. The load characteristic table T is stored in advance in the non-volatile memory 2b.

[0081] The correction amount calculation section 83 multiplies the computed load FL acting on the left travel device 50 by the loss torque coefficient C to calculate the left loss torque estimated value TlossL_est. The correction amount calculation section 83 multiplies the computed load FR acting on the right travel device 60 by the loss torque coefficient C to calculate the right loss torque estimated value TlossR_est.

[0082] The correction amount calculation section 83 computes a first correction amount Pc1 by converting the calculated left loss torque estimated value TlossL_est into a unit of pressure by using the motor volume q and the reduction ratio Ratio. In addition, the correction amount calculation section 83 computes a second correction amount Pc2 by converting the calculated right loss torque estimated value TlossR_est into a unit of pressure by using the motor volume q and the reduction ratio Ratio. The first correction amount Pc1 and the second correction amount Pc2 that are correction amounts of pressure are represented by the following equations (15) and (16). Pc 1 = 2 Π / q × Ratio × TlossL _ est Pc 2 = 2 Π / q × Ratio × TlossR _ est

[0083] The correction amount calculation section 83 outputs the first correction amount Pc1 and the second correction amount Pc2 calculated by the equations (15) and (16) to the differential pressure value calculation section 81.

[0084] The first correction amount Pc1 corresponds to a change in the first pump pressure P1 in the inclined posture relative to the first pump pressure P1 in the horizontal posture (difference between the first pump pressure P1 in the horizontal posture and the first pump pressure P1 in the inclined posture). The first correction amount Pc1 becomes larger as the height of the left travel device 50 becomes lower and the height of the right travel device 60 becomes higher in the inclined posture. In addition, the first correction amount Pc1 becomes smaller as the height of the left travel device 50 becomes higher and the height of the right travel device 60 becomes lower in the inclined posture. The second correction amount Pc2 corresponds to a change in the second pump pressure P2 in the inclined posture relative to the second pump pressure P2 in the horizontal posture (difference between the second pump pressure P2 in the horizontal posture and the second pump pressure P2 in the inclined posture). The second correction amount Pc2 becomes smaller as the height of the left travel device 50 becomes lower and the height of the right travel device 60 becomes higher in the inclined posture. In addition, the second correction amount Pc2 becomes larger as the height of the left travel device 50 becomes higher and the height of the right travel device 60 becomes lower in the inclined posture.

[0085] The differential pressure value calculation section 81 computes the differential pressure value ΔP by subtracting the second pump pressure P2 sensed by the second pressure sensor 23 from the first pump pressure P1 sensed by the first pressure sensor 13. The differential pressure value calculation section 81 corrects the differential pressure value ΔP by using the first correction amount Pc1 and the second correction amount Pc2. Specifically, the differential pressure value calculation section 81 computes the corrected differential pressure value ΔPc that is the differential pressure value after correction, by subtracting the first correction amount Pc1 and adding the second correction amount Pc2 from / to the differential pressure value ΔP. The corrected differential pressure value ΔPc is output to the effective differential pressure value extraction section 82. It should be noted that when the hydraulic excavator 100 is travelling straight ahead in the horizontal posture, the load FL and the load FR become equal to each other. That is, the first correction amount Pc1 and the second correction amount Pc2 become equal to each other. Therefore, the correction amount Pc (= second correction amount Pc2 - first correction amount Pc1) added to the differential pressure value ΔP becomes 0 (zero), and the differential pressure value ΔP (= ΔPc) in a case where the correction is not substantially performed is output to the effective differential pressure value extraction section 82.

[0086] As described above, the controller 2 according to the present embodiment computes the correction amount Pc (= Pc2 - Pc1) for canceling the influence of the inclination state of the lower track structure 101 on the first pump pressure P1 and the second pump pressure P2 on the basis of the inclination angle (roll angle φ) of the lower track structure 101 sensed by the inclination angle sensor 76. The correction amount Pc corresponds to a variation in the differential pressure value ΔP (difference between the differential pressure value in the horizontal posture and the differential pressure value in the inclined posture) due to an increase in the load acting on one of the left travel device 50 and the right travel device 60 and a decrease in the load acting on the other of the left travel device 50 and the right travel device 60 when the lower track structure 101 is inclined in the lateral direction. The controller 2 calculates the corrected differential pressure value ΔPc by canceling the variation in the differential pressure value with the horizontal posture as a difference, which is included in the differential pressure value ΔP computed in the inclined posture, by the correction amount Pc.

[0087] Fig. 12 is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller 2. The flowchart depicted in Fig. 12 is started by, for example, turning on the ignition switch and is repeatedly executed at a predetermined control cycle.

[0088] In Step S2, the differential pressure value calculation section 81 calculates the differential pressure value ΔP obtained by subtracting the second pump pressure P2 from the first pump pressure P1.

[0089] In the next Step S4, the correction amount calculation section 83 refers to the load characteristic table T and computes the load FL of the left travel device 50 and the load FR of the right travel device 60 on the basis of the roll angle φ of the lower track structure 101 sensed by the inclination angle sensor 76. The correction amount calculation section 83 calculates the first correction amount Pc1 and the second correction amount Pc2 on the basis of the loads FL and FR.

[0090] In the next Step S6, the differential pressure value calculation section 81 calculates the corrected differential pressure value ΔPc by adding the correction amount Pc (second correction amount Pc2 - first correction amount Pc1) calculated in Step S4 to the differential pressure value ΔP calculated in Step S2.

[0091] In the next Step S10, the state determination section 70 determines whether there is no work operation on the basis of the work operation signal from the work operation sensor 3. When it is determined in Step S10 that there is no work operation (Yes), the processing proceeds to Step S20, and when it is determined in Step S10 that there is a work operation (No), the invalid mode is set, and the processing depicted in Fig. 12 in the present control cycle is terminated. That is, the processing proceeds to Step S2 of the next control cycle.

[0092] In Step S20, the state determination section 70 determines whether there is no swing operation on the basis of the swing operation signal from the swing operation sensor 4. When it is determined in Step S20 that there is no swing operation (Yes), the processing proceeds to Step S30, and when it is determined in Step S20 that there is a swing operation (No), the invalid mode is set, and the processing depicted in Fig. 12 in the present control cycle is terminated.

[0093] In Step S30, the state determination section 70 determines whether or not there is a travelling operation on the basis of the travelling operation signal from the travelling operation sensor 5. When it is determined in Step S30 that there is a travelling operation (Yes), the processing proceeds to Step S40, and when it is determined in Step S30 that there is no travelling operation (No), the invalid mode is set, and the processing depicted in Fig. 12 in the present control cycle is terminated.

[0094] In Step S40, it is determined whether or not the hydraulic excavator 100 is travelling straight ahead on the basis of the first tilting command value and the second tilting command value. The state determination section 70 calculates the first tilting command value and the second tilting command value on the basis of the work operation signal, the swing operation signal, and the travelling operation signal. It should be noted that the state determination section 70 may acquire the first tilting command value and the second tilting command value calculated by a hydraulic pump control section (not illustrated).

[0095] Where the first tilting command value and the second tilting command value are equal to each other during the travelling single operation, the flow rates supplied from the first hydraulic pump 11 and the second hydraulic pump 21 to the left and right travelling motors 31 and 32 become equal to each other. At this time, the rotational speeds of the left and right travelling motors 31 and 32 become equal to each other, and the left and right travel devices 50 and 60 travel straight ahead. Thus, it is possible to determine whether or not the left and right travel devices 50 and 60 are travelling straight ahead on the basis of whether or not the first tilting command value and the second tilting command value are equal to each other. Specifically, in consideration of manufacturing errors of the first hydraulic pump 11, the second hydraulic pump 21, the left and right travelling motors 31 and 32, and the like, it is determined that the left and right travel devices 50 and 60 are travelling straight ahead when the difference between the first tilting command value and the second tilting command value is equal to or smaller than a predetermined threshold value.

[0096] When it is determined in Step S40 that the left and right travel devices 50 and 60 are travelling straight ahead (Yes), the valid mode is set, and the processing proceeds to Step S50, and when it is determined in Step S40 that the left and right travel devices 50 and 60 are not travelling straight ahead (No), the invalid mode is set, and the processing depicted in Fig. 12 in the present control period is terminated.

[0097] In Step S50, the effective differential pressure value extraction section 82 extracts the corrected differential pressure value ΔPc calculated in Step S6 of the present control cycle as the abnormality determination evaluation value used for abnormality determination. The abnormality determination evaluation value is a feature amount for evaluating abnormality sign states of the travel devices 50 and 60.

[0098] In the next Step S60, the abnormality determination section 90 determines whether or not the corrected differential pressure value ΔPc extracted as the abnormality determination evaluation value is equal to or smaller than a predetermined upper limit value Pu. The determination reference value (positive value) ΔP0 is employed for the predetermined upper limit value Pu. The determination reference value ΔP0 is set in advance in consideration of pressure sensing errors and manufacturing errors, and is stored in the non-volatile memory 2b. The manufacturing errors include, for example, manufacturing errors of the first hydraulic pump 11, the second hydraulic pump 21, and the left and right travel devices 50 and 60. The predetermined upper limit value Pu is a threshold value for determining whether or not there is an abnormality in the left travel device 50.

[0099] For example, where the loss torques of the left and right travel devices 50 and 60 are the same during travelling straight ahead on the horizontal road surface 109a, the left and right travelling motors 31 and 32 are equally driven by the first hydraulic pump 11 and the second hydraulic pump 21. Therefore, the first pump pressure P1 and the second pump pressure P2 become the same, and the corrected differential pressure value ΔPc becomes equal to or smaller than the predetermined upper limit value Pu (ΔPc ≤ Pu). It should be noted that when travelling on the horizontal road surface 109a, the corrected differential pressure value ΔPc corresponds to the differential pressure value ΔP. On the other hand, where the loss torque of the left travel device 50 is larger than the loss torque of the right travel device 60 during travelling straight ahead on the horizontal road surface 109a, the first pump pressure P1 becomes larger than the second pump pressure P2, and the corrected differential pressure value ΔPc (> 0) becomes larger than the predetermined upper limit value Pu (> 0) (ΔPc > Pu).

[0100] Where the hydraulic excavator 100 travels on the inclined road surface 109b, the influence of the pressure difference between the first pump pressure P1 and the second pump pressure P2 caused by the inclined posture is canceled by correction. Therefore, even where the hydraulic excavator 100 is travelling on the inclined road surface 109b, it can be determined, as similar to when travelling on the horizontal road surface 109a, that the pressure difference between the first pump pressure P1 and the second pump pressure P2 becomes larger due to the abnormality of the travel device 50 or 60 by comparing the corrected differential pressure value ΔPc with the upper limit value Pu.

[0101] When it is determined in Step S60 that the corrected differential pressure value ΔPc is larger than the predetermined upper limit value Pu (No), the processing proceeds to Step S70, and when it is determined in Step S60 that the corrected differential pressure value ΔPc is equal to or smaller than the predetermined upper limit value Pu (Yes), the processing proceeds to Step S80.

[0102] In Step S70, the abnormality determination section 90 determines that there is an abnormality in the left travel device 50, and advances the processing to Step S110.

[0103] In Step S80, the abnormality determination section 90 determines whether or not the corrected differential pressure value ΔPc extracted as the abnormality determination evaluation value is equal to or larger than a predetermined lower limit value Pl. For the predetermined lower limit value Pl, a value (-ΔP0) obtained by multiplying the determination reference value ΔP0 by -1 is employed. The predetermined lower limit value Pl is a threshold value for determining whether or not there is an abnormality in the right travel device 60. It should be noted that the present invention is not limited to the case where the absolute value of the lower limit value Pl and the absolute value of the upper limit value Pu are made equal to each other. The absolute value of the lower limit value Pl and the absolute value of the upper limit value Pu may be different from each other.

[0104] For example, where the loss torques of the left and right travel devices 50 and 60 are the same during travelling straight ahead on the horizontal road surface 109a, the left and right travelling motors 31 and 32 are equally driven by the first hydraulic pump 11 and the second hydraulic pump 21. Therefore, the first pump pressure P1 and the second pump pressure P2 become the same, and the corrected differential pressure value ΔPc becomes equal to or larger than the predetermined lower limit value Pl (ΔPc ≥ Pl). It should be noted that when travelling on the horizontal road surface 109a, the corrected differential pressure value ΔPc corresponds to the differential pressure value ΔP. On the other hand, where the loss torque of the right travel device 60 is larger than the loss torque of the left travel device 50 during travelling straight ahead on the horizontal road surface 109a, the second pump pressure P2 becomes larger than the first pump pressure P1, and the corrected differential pressure value ΔPc (< 0) becomes smaller than the predetermined lower limit value Pl (< 0) (ΔPc < Pl).

[0105] Where the hydraulic excavator 100 travels on the inclined road surface 109b, the influence of the pressure difference between the first pump pressure P1 and the second pump pressure P2 caused by the inclined posture is canceled by correction. Therefore, even where the hydraulic excavator 100 is travelling on the inclined road surface 109b, it can be determined, as similar to when travelling on the horizontal road surface 109a, that the pressure difference between the first pump pressure P1 and the second pump pressure P2 becomes larger due to the abnormality of the travel device 50 or 60, by comparing the corrected differential pressure value ΔPc with the lower limit value Pl.

[0106] When it is determined in Step S80 that the corrected differential pressure value ΔPc is smaller than the predetermined lower limit value Pl (No), the processing proceeds to Step S90, and when it is determined in Step S80 that the corrected differential pressure value ΔPc is equal to or larger than the predetermined lower limit value Pl (Yes), the processing proceeds to Step S100.

[0107] In Step S90, the abnormality determination section 90 determines that there is an abnormality in the right travel device 60, and advances the processing to Step S110.

[0108] In Step S100, the abnormality determination section 90 determines that there is no abnormality (that is, normal) in the left and right travel devices 50 and 60, and advances the processing to Step S110.

[0109] In Step S110, the abnormality determination section 90 outputs the determination results in Step S70, S90, or S100 to the display device 91 and the communication device 92. The display device 91 displays an image (an icon or the like) representing the determination results on the display screen. That is, the controller 2 notifies the operator of the determination results via the display device 91. The communication device 92 transmits the determination results to the server 40. The server 40 outputs the received determination results to a display device in the management facility. The display device in the management facility displays an image (an icon or the like) representing the determination results on the display screen. That is, the controller 2 notifies the vehicle manager and the service person in the management facility of the determination results via the communication by the communication device 92. When the output processing of the determination results (Step S110) is completed, the processing depicted in Fig. 12 in the present control cycle is terminated.

[0110] As described above, in the present embodiment, the controller 2 computes the correction amount Pc of the differential pressure value ΔP on the basis of the roll angle (inclination angle) φ of the lower track structure 101, and computes the corrected differential pressure value ΔPc as the abnormality determination evaluation value used for abnormality determination by using the correction amount Pc. The corrected differential pressure value ΔPc corresponds to the differential pressure value obtained by canceling the variation due to the influence of the inclination. Therefore, even where the driving force difference is generated by the inclination, the influence of the inclination state is canceled. As a result, the differential pressure value ΔP equal to that when travelling straight ahead on the horizontal plane is calculated as the corrected differential pressure value ΔPc. Accordingly, the accuracy of the state monitoring of the travel system is improved regardless of the inclination situation.

[0111] According to the first embodiment described above, the following action and effect are exhibited. (1) The diagnostic device 80 is provided with the processor (first processor) 2a that diagnoses an abnormality of the travel devices 50 and 60 on the basis of the travelling feature amount (differential pressure value ΔP) representing the travelling states of the travel devices 50 and 60 mounted to the machine body 107 of the hydraulic excavator (work machine) 100, and the output device (the display device 91 and the communication device 92) that outputs the result of the diagnosis performed by the processor 2a. The processor 2a acquires the inclination feature amount (roll angle φ) representing the inclination state of the machine body 107. The processor 2a computes the correction amount Pc for canceling the influence of the inclination state of the machine body 107 on the travelling feature amounts (differential pressure value ΔP) of the travel devices 50 and 60 on the basis of the inclination feature amount (roll angle φ). The processor 2a computes the corrected travelling feature amount (corrected differential pressure value ΔPc) by correcting the travelling feature amount (differential pressure value ΔP) on the basis of the correction amount Pc. The processor 2a computes the abnormality determination evaluation value (corrected differential pressure value ΔPc in the valid mode) on the basis of the corrected travelling feature amount (corrected differential pressure value ΔPc). The processor 2a determines whether or not there is an abnormality in the travel device 50 or 60 on the basis of the abnormality determination evaluation value, and outputs, when it is determined that there is an abnormality, the determination result to the output device.

[0112] For example, the display device 91 as the output device outputs a notification image for informing the operator that an abnormality has occurred. In addition, the communication device 92 as the output device outputs to the server 40 notification information for informing the vehicle manager and the service person that an abnormality has occurred.

[0113] According to this configuration, it is possible to provide the diagnostic device 80 that prevents erroneous detection of an abnormality of the travel devices 50 and 60 when travelling on the inclined road surface, and is capable of appropriately detecting an abnormality of the travel devices 50 and 60.

[0114] (2) In the first embodiment, the hydraulic excavator 100 is provided with the diagnostic device 80. The hydraulic excavator 100 is provided with the machine body 107, the work device 103 that is attached to the machine body 107, the first hydraulic pump 11 and the second hydraulic pump 21 that are provided in the machine body 107, the left travel device 50 that has the left travelling motor 31 driven by hydraulic fluid supplied from the first hydraulic pump 11, the right travel device 60 that has the right travelling motor 32 driven by hydraulic fluid supplied from the second hydraulic pump 21, the travelling lever devices (travelling operation devices) 6 and 7 that issue instructions of operations of the left travel device 50 and the right travel device 60, the processor (first processor) 2a that controls the volumes (displacement volumes) of the first hydraulic pump 11 and the second hydraulic pump 21 in accordance with the operations of the travelling lever devices 6 and 7, the first pressure sensor 13 that senses the first pump pressure P1 that is the delivery pressure of the first hydraulic pump 11, the second pressure sensor 23 that senses the second pump pressure P2 that is the delivery pressure of the second hydraulic pump 21, and the inclination angle sensor (inclination state sensor) 76 that senses the inclination angle (inclination state) of the machine body 107 with respect to a horizontal plane. The machine body 107 has the lower track structure 101 provided with the left travel device 50 and the right travel device 60, and the upper swing structure 102 swingably provided with respect to the lower track structure 101.

[0115] The processor 2a computes the differential pressure value ΔP between the first pump pressure P1 and the second pump pressure P2 as the travelling feature amount. The processor 2a computes the roll angle φ that is the inclination angle of the machine body 107 in the lateral direction as the inclination feature amount on the basis of a sensor value representing the inclination angle (inclination state) sensed by the inclination angle sensor 76. The processor 2a computes the correction amount Pc (second correction amount Pc2 - first correction amount Pc1) for canceling the influence of the inclination state of the lower track structure 101 configuring the machine body 107 on the first pump pressure P1 and the second pump pressure P2 on the basis of the roll angle (inclination angle) φ of the lower track structure 101.

[0116] The processor 2a computes, as the correction amount Pc, a variation in the differential pressure value ΔP caused by an increase in the load acting on one of the left travel device 50 and the right travel device 60 and a decrease in the load acting on the other of the left travel device 50 and the right travel device 60 due to the inclination of the lower track structure 101 in the lateral direction.

[0117] The processor 2a computes the corrected differential pressure value ΔPc as a corrected travelling feature amount by correcting the computed differential pressure value ΔP on the basis of the correction amount Pc. The processor 2a computes the abnormality determination evaluation value on the basis of the computed corrected differential pressure value ΔPc. It should be noted that in the present embodiment, the corrected differential pressure value ΔPc is employed for the abnormality determination evaluation value. The processor 2a determines whether or not there is an abnormality in either one of the left travel device 50 and the right travel device 60 on the basis of the computed corrected differential pressure value ΔPc as the abnormality determination evaluation value. When it is determined that there is an abnormality, the processor 2a outputs the determination result to the output device (the display device 91 and the communication device 92). According to this configuration, it is possible to prevent erroneous detection of an abnormality of the travel devices 50 and 60 when the hydraulic excavator 100 provided with the hydraulically-driven travel devices 50 and 60 is travelling on the inclined road surface. According to the present embodiment, it is possible to appropriately diagnose the presence or absence of an abnormality of the travel devices 50 and 60 even when the hydraulic excavator 100 is travelling in a state of being inclined to the left and right.

[0118] (3) When it is determined that the left travel device 50 and the right travel device 60 are travelling straight ahead, the processor 2a makes the determination of an abnormality. When the lower track structure 101 is travelling while being swung to the left and right by making a difference between the speeds of the left and right travel devices 50 and 60, there is a risk that the abnormality of the travel devices 50 and 60 cannot be accurately detected depending on the difference between the left and right speeds. Accordingly, in the present embodiment, an abnormality is determined when the left travel device 50 and the right travel device 60 are travelling straight ahead. Therefore, it is possible to accurately detect an abnormality of the left and right travel devices 50 and 60.

[0119] (4) When it is determined that the work device 103 and the upper swing structure 102 are not operated, the processor 2a makes the determination of an abnormality. When at least one of the work device 103 and the upper swing structure 102 is operated, the load balance between the left and right of the machine body 107 changes due to the operation, and there is a risk that the abnormality of the travel devices 50 and 60 cannot be accurately detected. Accordingly, in the present embodiment, an abnormality is determined when the work device 103 and the upper swing structure 102 are not operated. Therefore, it is possible to accurately detect an abnormality of the left and right travel devices 50 and 60.<Modified example of first embodiment>

[0120] In the first embodiment, an example in which the travelling feature amount is the differential pressure value ΔP has been described, but the travelling feature amount is not limited thereto. For example, the travelling feature amount may be a driving force difference that is a difference between the travel driving force of the left travel device 50 and the travel driving force of the right travel device 60. According to this configuration, the present invention can be applied to a travel device of an electrically driven motor driving type. The travel driving force of the electrically driven travel device may be computed on the basis of a torque sensed by a torque sensor, or may be estimated on the basis of a current and a voltage sensed by a current sensor and a voltage sensor, respectively.

[0121] In addition, in the first embodiment, an example in which the inclination feature amount is the roll angle φ has been described, but the inclination feature amount is not limited thereto. For example, the inclination feature amount may be a distance difference that is a difference between a distance of the left travel device 50 from the reference plane in the vertical direction and a distance of the right travel device 60 from the reference plane in the vertical direction. Since the width of the travel device (the distance between the left travel device 50 and the right travel device 60) is known, the distance difference can be said to be a parameter representing the inclination state. It should be noted that in the following embodiment, an example in which the travelling feature amount is the differential pressure value ΔP and the inclination feature amount is the roll angle φ as similar to the first embodiment will be described. However, the travelling feature amount may be a parameter representing the travelling state, and the inclination feature amount may be a parameter representing the inclination state, as similar to the modified example.<Second Embodiment>

[0122] A hydraulic excavator 100 according to a second embodiment of the present invention will be described with reference to Fig. 13 to Fig. 15. It should be noted that the same reference symbols are given to the configurations same as or corresponding to those described in the first embodiment, and differences will be mainly described.

[0123] Fig. 13 is a diagram similar to that of Fig. 10 and is a functional block diagram of a controller 202 according to the second embodiment. The controller 202 has an inclination state determination section 277 instead of the correction amount calculation section 83 of the controller 2 according to the first embodiment. In addition, the controller 202 has a differential pressure value calculation section 281, an effective differential pressure value extraction section 282, and an abnormality determination section 290 instead of the differential pressure value calculation section 81, the effective differential pressure value extraction section 82, and the abnormality determination section 90 of the controller 2 according to the first embodiment. The processor 2a of the controller 202 realizes these functions by executing the programs stored in the non-volatile memory 2b.

[0124] In the second embodiment, the correction of the differential pressure value described in the first embodiment is not performed. Therefore, where the difference (hereinafter, also referred to as a load difference due to inclination) ΔF of the loads FL and FR on the inclined road surface 109b from the loads FL and FR on the horizontal road surface 109a becomes larger than a predetermined value (hereinafter, also referred to as an allowable load difference) ΔFt, there is a risk that the abnormality detection on the basis of the differential pressure value ΔP cannot be accurately performed. Thus, the controller 2 according to the second embodiment is configured not to execute the abnormality determination based on the differential pressure value ΔP in a case where the load difference ΔF due to inclination becomes larger than the allowable load difference ΔFt.

[0125] Fig. 14 is a diagram for depicting an allowable load difference and an allowable roll angle range.

[0126] As depicted in Fig. 14, in the present embodiment, the magnitude of the roll angle φ (the absolute value of the roll angle φ) of the lower track structure 101 when the ratio of the smaller load between the loads FL and FR is 90% to the loads FL and FR on the horizontal road surface 109a is defined as an allowable roll angle φt. In addition, a range of a lower limit angle (-φt) or larger and an upper limit angle (+φt) or smaller is defined as an allowable roll angle range. The upper limit angle (+φt) corresponds to the allowable roll angle φt (positive value). The lower limit angle (-φt) corresponds to a value obtained by multiplying the allowable roll angle φt by -1. Where the roll angle φ is within the allowable roll angle range depicted in Fig. 14, the accuracy of the abnormality determination can be secured.

[0127] Fig. 15 is a diagram similar to that of Fig. 12 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller 202 according to the second embodiment. In the flowchart of Fig. 15, the processing of Steps S4 and S6 of the flowchart of Fig. 12 is omitted. That is, the differential pressure value calculation section 281 depicted in Fig. 13 outputs the computed differential pressure value ΔP to the effective differential pressure value extraction section 82 without correction. In addition, in the flowchart of Fig. 15, processing of Steps S250, S260, and S280 is executed instead of the processing of Steps S50, S60, and S80 of the flowchart of Fig. 12. Further, in the second embodiment, when positive determination is made in Step S40, inclination state determination processing (Step S245) is executed.

[0128] As depicted in Fig. 15, when positive determination is made in Step S40, the processing proceeds to Step S245. In Step S245, the inclination state determination section 277 determines whether or not the roll angle φ sensed by the inclination angle sensor 76 is within the allowable roll angle range. Where the roll angle φ is equal to or larger than the lower limit angle (-φt) and equal to or smaller than the upper limit angle (+φt), it is determined that the roll angle φ is within the allowable roll angle range. When it is determined that the roll angle φ is within the allowable roll angle range (Yes), the valid mode is set, and the processing proceeds to Step S250. Where the roll angle φ is smaller than the lower limit angle (-φt) or the roll angle φ is larger than the upper limit angle (+φt), it is determined that the roll angle φ is not within the allowable roll angle range. When it is determined that the roll angle φ is not within the allowable roll angle range (No), the invalid mode is set, and the processing depicted in Fig. 15 in the present control cycle is terminated.

[0129] In Step S250, the effective differential pressure value extraction section 282 extracts the differential pressure value ΔP calculated in Step S2 of the present control cycle as the abnormality determination evaluation value used for abnormality determination.

[0130] In the next Step S260, the abnormality determination section 290 determines whether or not the differential pressure value ΔP extracted as the abnormality determination evaluation value is equal to or smaller than the predetermined upper limit value Pu. When it is determined in Step S260 that the differential pressure value ΔP is larger than the predetermined upper limit value Pu (No), the processing proceeds to Step S70, and when it is determined in Step S260 that the differential pressure value ΔP is equal to or smaller than the predetermined upper limit value Pu (Yes), the processing proceeds to Step S280.

[0131] In Step S280, the abnormality determination section 290 determines whether or not the differential pressure value ΔP extracted as the abnormality determination evaluation value is equal to or larger than the predetermined lower limit value Pl. When it is determined in Step S280 that the differential pressure value ΔP is smaller than the predetermined lower limit value Pl (No), the processing proceeds to Step S90, and when it is determined in Step S280 that the differential pressure value ΔP is equal to or larger than the predetermined lower limit value Pl (Yes), the processing proceeds to Step S100.

[0132] As described above, in the second embodiment, when the absolute value of the roll angle φ (the magnitude of the roll angle φ) of the lower track structure 101 is larger than the predetermined angle φt, the abnormality determination processing is not executed because the abnormality determination processing is affected. The predetermined angle φt is a threshold value of the roll angle φ for determining whether or not the inclination state affects the abnormality determination processing of the travel devices 50 and 60. The predetermined angle φt corresponds to the roll angle φ of, for example, ±10% (in the present embodiment, -10%) with respect to the balanced load when there is no inclination (φ = 0°). Therefore, the abnormality determination processing is executed only in a case where the change in the load due to inclination is within ±10%.

[0133] According to the second embodiment described above, the following action and effect are exhibited.

[0134] The processor 2a of the controller 202 computes the abnormality determination evaluation value on the basis of the differential pressure value ΔP between the first pump pressure P1 and the second pump pressure P2. It should be noted that in the present embodiment, the differential pressure value ΔP is employed for the abnormality determination evaluation value. Where the absolute value |φ| of the roll angle (the inclination angle of the machine body 107) φ of the lower track structure 101 is equal to or smaller than the predetermined angle φt and the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is larger than the determination reference value ΔP0, the processor 2a of the controller 202 determines that there is an abnormality in either one of the left travel device 50 and the right travel device 60. When it is determined that there is an abnormality, the processor 2a of the controller 202 outputs the determination result to the output device (the display device 91 and the communication device 92). When the absolute value |φ| of the roll angle (the inclination angle of the machine body 107) φ of the lower track structure 101 is larger than the predetermined angle φt, or when the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is equal to or smaller than the determination reference value ΔP0, the processor 2a of the controller 202 does not determine that there is an abnormality in either one of the left travel device 50 and the right travel device 60.

[0135] According to this configuration, where the inclination angle of the inclined road surface 109b, that is, the roll angle φ of the lower track structure 101 is equal to or smaller than the predetermined angle φt, the abnormality determination processing is executed on the basis of the differential pressure value ΔP. On the other hand, where the roll angle φ of the lower track structure 101 is larger than the predetermined angle φt, the abnormality determination processing based on the differential pressure value ΔP is not executed. Accordingly, it is possible to suppress erroneous detection of an abnormality caused by execution of the abnormality determination processing in a situation that is easily affected by the inclination angle of the inclined road surface 109b. That is, in the second embodiment, it is possible to provide the hydraulic excavator 100 capable of preventing erroneous detection of an abnormality of the travel devices 50 and 60 when travelling on the inclined road surface 109b as similar to the first embodiment. According to the present embodiment, the influence of the inclination on the abnormality determination processing can be eliminated, and the abnormality of the travel devices 50 and 60 can be accurately detected.<Third Embodiment>

[0136] A hydraulic excavator 100 according to a third embodiment of the present invention will be described with reference to Fig. 16 to Fig. 19. It should be noted that the same reference symbols are given to the configurations same as or corresponding to those described in the second embodiment, and differences will be mainly described.

[0137] In the first embodiment and the second embodiment, an example in which the roll angle φ of the lower track structure 101 is sensed by the inclination angle sensor 76 attached to the lower track structure 101 has been described. On the other hand, in the third embodiment, the roll angle φ of the lower track structure 101 is indirectly sensed on the basis of a sensed result of a swing structure inclination angle sensor 376a attached to the upper swing structure 102 and the swing angle of the upper swing structure 102 with respect to the lower track structure 101. That is, the swing structure inclination angle sensor 376a and the swing angle sensor 376b configure an inclination angle sensing device 376 of the lower track structure 101. The upper swing structure 102 has the operation room 110 and the enclosure for storing the engine and the like, and is better in installation property of sensors and the like compared with the lower track structure 101. In addition, it is also excellent in environment resistance.

[0138] Fig. 16 is a schematic view for depicting inclination angles (a roll angle φtrv and a pitch angle θtrv) of the lower track structure 101 and inclination angles (a roll angle φswg and a pitch angle θswg) of the upper swing structure 102.

[0139] As depicted in Fig. 16, in the hydraulic excavator 100, for example, a track structure reference coordinate system that is a coordinate system using the lower track structure 101 as a reference and a swing structure reference coordinate system that is a coordinate system using the upper swing structure 102 as a reference are set. Fig. 16 schematically depicts the relationship between the track structure reference coordinate system and the swing structure reference coordinate system.

[0140] The track structure reference coordinate system corresponds to the machine body coordinate system described in the first embodiment. The track structure reference coordinate system is defined as a right-handed coordinate system using as the origin an arbitrary point on the swing centerline that is the rotation axis of the upper swing structure 102. In the track structure reference coordinate system, the forward direction of the lower track structure 101 is defined as the positive direction of the Xtrv axis. In the track structure reference coordinate system, the vertically upper direction along the swing centerline is defined as the positive direction of the Z axis. In the track structure reference coordinate system, the left direction of the lower track structure 101 orthogonal to each of the Xtrv axis and the Z axis is defined as the positive direction of the Ytrv axis.

[0141] The swing structure reference coordinate system is defined as a right-handed coordinate system using as the origin an arbitrary point on the swing centerline that is the rotation axis of the upper swing structure 102. In the swing structure reference coordinate system, the front direction of the upper swing structure 102 is defined as the positive direction of the Xswg axis. In the swing structure reference coordinate system, the vertically upper direction along the swing centerline is defined as the positive direction of the Z axis. In the swing structure reference coordinate system, the left direction of the upper swing structure 102 orthogonal to each of the Xswg axis and the Z axis is defined as the positive direction of the Ysyg axis.

[0142] The Z axis of the track structure reference coordinate system and the Z axis of the swing structure reference coordinate system are common. The rotation angle in the Xtrv-Z plane orthogonal to the Ytrv axis is represented by the pitch angle θtrv of the lower track structure 101. The rotation angle in the Xtrv-Ytrv plane orthogonal to the Z axis is represented by the yaw angle ψtrv of the lower track structure 101. The rotation angle in the Ytrv-Z plane orthogonal to the Xtrv axis is represented by the roll angle φtrv of the lower track structure 101. The Xtrv axis is an axis along the advancing direction of the lower track structure 101, and the roll angle φtrv with the Xtrv axis as the rotation axis corresponds to the lateral inclination angle of the lower track structure 101 with respect to the horizontal plane. The Ytrv axis is an axis parallel to the rotation axes of the travelling motors 31 and 32, and the pitch angle θtrv with the Ytrv axis as the rotation axis corresponds to the longitudinal inclination angle of the lower track structure 101 with respect to the horizontal plane.

[0143] The rotation angle in the Xswg-Z plane orthogonal to the Yswg axis is represented by the pitch angle θswg of the upper swing structure 102. The rotation angle in the Xswg-Yswg plane orthogonal to the Z axis is represented by the yaw angle ψswg of the upper swing structure 102. The rotation angle in the Yswg-Z plane orthogonal to the Xswg axis is represented by the roll angle φ of the upper swing structure 102. The Xswg axis is an axis along the front of the upper swing structure (the front of the operation room 110), and the roll angle φ with the Xswg axis as the rotation axis corresponds to the lateral inclination angle of the upper swing structure 102 with respect to the horizontal plane. The Yswg axis is an axis parallel to the rotation axis of the boom 104, and the pitch angle θswg with the Yswg axis as the rotation axis corresponds to the longitudinal inclination angle of the upper swing structure 102 with respect to the horizontal plane. It should be noted that the difference between the yaw angle ψtrv of the lower track structure 101 and the yaw angle ψswg of the upper swing structure 102 corresponds to the swing angle ψ.

[0144] The upper swing structure 102 rotates relative to the lower track structure 101. Therefore, when the direction of the upper swing structure 102 and the direction of the lower track structure 101 do not coincide with each other, the inclination angle of the upper swing structure 102 and the inclination angle of the lower track structure 101 are not equal to each other. For example, when the roll angle φswg of the upper swing structure 102 is 10°, the relationship between the swing angle ψ and the roll angle φtrv of the lower track structure 101 and the relationship between the swing angle ψ and the pitch angle θtrv of the lower track structure 101 are represented by graphs depicted in Fig. 17.

[0145] The roll angle (hereinafter, also referred to as a track structure roll angle) φtrv of the lower track structure 101 is represented by an equation (17). In addition, the pitch angle (hereinafter, also referred to as a track structure pitch angle) θtrv of the lower track structure 101 is represented by an equation (18). φtrv = φswg × cosψ + θswg × sinψ φtrv = φswg × sinψ + θswg × cosψ

[0146] As depicted in Fig. 16, φswg is the roll angle (hereinafter, also referred to as a swing structure roll angle) of the upper swing structure 102, θswg is the pitch angle (hereinafter, also referred to as a swing structure pitch angle) of the upper swing structure 102, and ψ is the swing angle.

[0147] Fig. 18 is a diagram similar to that of Fig. 13 and is a functional block diagram of a controller 302 according to the third embodiment. The controller 302 has an inclination state determination section 377 instead of the inclination state determination section 277 of the controller 202 according to the second embodiment. A processor 2a of the controller 302 realizes these functions by executing the programs stored in the non-volatile memory 2b.

[0148] The inclination angle sensing device (inclination state sensor) 376 has a swing structure inclination angle sensor 376a, a swing angle sensor 376b, and an inclination calculation section 378. The swing structure inclination angle sensor 376a senses the inclination angle of the upper swing structure 102 with respect to a reference plane (for example, a horizontal plane) and outputs a signal representing the sensed result to the inclination calculation section 378. The swing angle sensor 376b is provided in the machine body 107, senses the swing angle ψ that is the rotation angle of the upper swing structure 102 with respect to the lower track structure 101, and outputs a signal representing the sensed result to the inclination calculation section 378. The swing structure inclination angle sensor 376a can employ an IMU (Inertial Measurement Unit) that acquires angular velocities and accelerations of orthogonal three axes as information related to the posture, computes the inclination angles (the swing structure roll angle φswg and the swing structure pitch angle θswg) on the basis of the information, and outputs signals representing the inclination angles φswg and θswg to the inclination calculation section 378. The inclination calculation section 378 calculates the track structure roll angle φtrv on the basis of the information (the swing structure roll angle φswg, the swing structure pitch angle θswg, and the swing angle ψ) representing the posture of the upper swing structure 102. The inclination calculation section 378 is configured with a microcomputer (computation device) having a processor such as a CPU, and a memory such as a ROM and a RAM. It should be noted that the function of the inclination calculation section 378 may be provided in the controller 302 that is a computation device.

[0149] Fig. 19 is a diagram similar to that of Fig. 15 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller 302 according to the third embodiment. In the flowchart of Fig. 19, processing of Step S307 is added between Step S2 and Step S10 of the flowchart of Fig. 15.

[0150] As depicted in Fig. 19, when the differential pressure calculation processing (Step S2) is terminated, the processing proceeds to Step S307. In Step S307, the inclination state determination section 377 acquires the track structure roll angle φ calculated by the inclination calculation section 378. It should be noted that the inclination calculation section 378 acquires the swing structure roll angle φswg, the swing structure pitch angle θswg, and the swing angle ψ sensed by the inclination angle sensing device 376 at a predetermined computation cycle, calculates the track structure roll angle φtrv, and outputs it to the controller 302.

[0151] According to the third embodiment described above, the following action and effect are exhibited in addition to the similar action and effect of the second embodiment.

[0152] The inclination angle sensing device (inclination state sensor) 376 includes the swing structure inclination angle sensor 376a that is attached to the upper swing structure 102 and senses the inclination angles (the roll angle φswg and the pitch angle θswg) of the upper swing structure 102 with respect to the horizontal plane, the swing angle sensor 376b that senses the swing angle ψ of the upper swing structure 102 with respect to the lower track structure 101, and the inclination calculation section (computation device) 378 that computes the roll angle φtrv that is the inclination angle of the lower track structure 101 in the lateral direction with respect to the horizontal plane on the basis of the inclination angles φswg and θswg of the upper swing structure 102 sensed by the swing structure inclination angle sensor 376a and the swing angle ψ of the upper swing structure 102 sensed by the swing angle sensor 376b. When the absolute value |φtrv| of the roll angle φtrv of the lower track structure 101 sensed by the inclination angle sensing device 376 is equal to or smaller than the predetermined angle φt and the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is larger than the determination reference value ΔP0, the processor 2a of the controller 302 determines that there is an abnormality in either one of the left travel device 50 and the right travel device 60. Where the absolute value |φtrv| of the roll angle φtrv of the lower track structure 101 sensed by the inclination angle sensing device 376 is larger than the predetermined angle φt or where the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is equal to or smaller than the determination reference value ΔP0, the processor 2a of the controller 302 does not determine that there is an abnormality in either one of the left travel device 50 and the right travel device 60.

[0153] The lower track structure 101 has a mechanism for rotatably coupling the upper swing structure 102, and it is not easy to install a sensor and the like. In the third embodiment, it is not necessary to install the inclination angle sensor 76 in the lower track structure 101. Therefore, the configuration of the hydraulic excavator 100 can be simplified and the manufacturing cost can be reduced.<Fourth Embodiment>

[0154] A diagnostic system 410 according to a fourth embodiment of the present invention will be described with reference to Fig. 20 and Fig. 21. It should be noted that the same reference symbols are given to the configurations same as or corresponding to those described in the first embodiment, and differences will be mainly described.

[0155] The hardware configuration of a hydraulic excavator 400 is similar to that of the hydraulic excavator 100 described in the first embodiment. In the first embodiment, an example in which the diagnostic device 80 includes the controller 2 mounted on the hydraulic excavator 100 and the output device (the display device 91 and the communication device 92) has been described. On the other hand, in the fourth embodiment, a diagnostic device 480 includes a server 440 provided in a management facility and an output device (a display device 462 and a communication device 498). That is, in the fourth embodiment, the server 440 diagnoses an abnormality of the travel devices 50 and 60 of the hydraulic excavator 400 on the basis of feature amounts acquired from one or more hydraulic excavators 100. Therefore, a controller 402 of the hydraulic excavator 400 has a function of computing feature amounts but does not have a function of diagnosing an abnormality.

[0156] In the fourth embodiment, processing of collecting feature amounts from a plurality of hydraulic excavators 100 and performing analysis, comparison, and judgement can be handled simultaneously or in combination. Therefore, it is possible to analyze and diagnose data overviewing the entirety.

[0157] Fig. 20 is a diagram for depicting a configuration of the diagnostic system 410 according to the fourth embodiment. The diagnostic system 410 includes one or more hydraulic excavators 400 for conducting work at a work site and the diagnostic device 480 provided in a management facility. The management facility is provided at a place away from the work site. The hydraulic excavator 400 and the diagnostic device 480 are configured to be capable of performing bidirectional communication via a communication line NT of a wide area network. That is, the hydraulic excavator 400 and the diagnostic device 480 can transmit and receive information (data) via the communication line NT. The communication line NT is a mobile phone communication network (mobile communication network) developed by a mobile carrier and the like, a satellite communication network, the Internet, or the like. The diagnostic device 480 includes the server 440, an input device 461, the display device 462, and the communication device 498.

[0158] The controller 402 mounted on the hydraulic excavator 400 and the server 440 installed in the management facility are computers provided with processors 402a and 440a such as CPUs, non-volatile memories 402b and 440b that are storage devices (memories), and volatile memories 402c and 440c, respectively, as similar to the controller 2 of the first embodiment. In addition, the controller 402 and the server 440 are provided with input interfaces 402d and 440d and output interfaces 402e and 440e, respectively. It should be noted that each of the controller 402 and the server 440 may be configured by one computer or a plurality of computers.

[0159] The server 440 collects feature amounts (a travelling feature amount and an inclination feature amount) from the hydraulic excavator 400 via the communication device 498 as a receiver. The server 440 analyzes the tendency of the operation and deterioration of the hydraulic excavator 400 from time-series behaviors of the feature amounts, compares the feature amounts with a threshold value, and makes various determinations. In addition, the server 440 compares the feature amounts of the plurality of hydraulic excavators 400 with each other to identify a hydraulic excavator 400 that is transmitting a feature amount deviated from the average feature amount, and conducts various analyses on the basis of the degree of the deviation of the feature amount. Further, the server 440 can make various determinations using other statistical analysis methods or the like.

[0160] The display device 462 such as a liquid crystal monitor, the input device 461 such as a keyboard, and the communication device 498 for exchanging information with each hydraulic excavator 400 via the communication line NT are connected to the server 440. The display device 462 is an output device that is controlled by the server 440 and outputs a computation result of the server 440 as an image. The communication device 498 is an output device that is connected to the communication line NT and outputs the computation result of the server 440 to the hydraulic excavator 400.

[0161] In the first embodiment depicted in Fig. 10, the controller 2 may calculate the abnormality determination evaluation value (corrected differential pressure value ΔPc) from the first pump pressure P1, the second pump pressure P2, and the machine body roll angle φ, and transmit the abnormality determination evaluation value to the server 40 via the communication device 92. In addition, the server 40 according to the first embodiment may have an analysis function of performing storing, analysis, comparison, and determination regarding the acquired data. If an abnormality is found by analysis, the server 40 displays information of the hydraulic excavator 100 in which the abnormality has been found on the display device such as a liquid crystal monitor. Accordingly, the vehicle manager can easily identify the hydraulic excavator 100 in which the abnormality has occurred. In addition, the server 40 may transmit information for informing that the abnormality has occurred to the hydraulic excavator 100 in which the abnormality has been found, or may transmit information for informing that the abnormality has occurred to the vehicle manager, the operator, or the like by using notification means such as an e-mail. However, where such a system is used, handling in operation management may be complicated.

[0162] For example, in the first embodiment, the abnormality determination evaluation value and the determination reference value are compared with each other and the presence or absence of an abnormality is determined, in each of the plurality of hydraulic excavators 100. Here, the correction amount Pc according to the roll angle φ of the hydraulic excavator 100 is used for calculation of the abnormality determination evaluation value. Although the coefficient (for example, the loss torque coefficient C) and the load characteristic table T used for calculation of the correction amount Pc may be set in advance on the basis of design values or the tendency of past measurement data as in the first embodiment, it is preferable to acquire and adjust actual operation information of the hydraulic excavator 100. Therefore, the correction amount parameters (for example, the loss torque coefficient C and the load characteristic table T) necessary for calculating the correction amount Pc may be reviewed while confirming the operation information of the hydraulic excavator 100 in the early stage of operation.

[0163] This review work of the correction amount parameters is useful because an appropriate correction amount PC can be obtained. However, in the first embodiment, the calculation of the correction amount Pc and the correction processing using the correction amount Pc are performed by the controller 2 of each hydraulic excavator 100. Therefore, in order to modify the correction amount parameters necessary for calculating the correction amount Pc or to change the correction logic (correction method), modification work (rewriting work) of software is necessary for each of the plurality of the hydraulic excavators 100. For example, where the correction amount parameters need to be modified in a certain model of the hydraulic excavator 100, software needs to be similarly modified for all of the corresponding hydraulic excavators 100, which requires a lot of time and effort. In addition, it becomes necessary to monitor the operation of the hydraulic excavator 100 with the correction amount parameters modified to confirm whether the modification is appropriate in each of the plurality of hydraulic excavators 100, which requires a lot of time and effort for management work.

[0164] In contrast, in the diagnostic system 410 according to the fourth embodiment, the work of modifying the correction amount parameters and changing the correction logic (correction method) can be easily conducted, and further, management after the modification can be easily performed. The details thereof will be described below.

[0165] Fig. 21 is a functional block diagram of the diagnostic system 410 according to the fourth embodiment. As depicted in Fig. 21, the controller 402 has a state determination section 70, a travelling state amount calculation section 495, an inclination state amount calculation section 496, and a feature amount computation section 482. A processor 402a of the controller 402 realizes these functions by executing the programs stored in the non-volatile memory 402b. In addition, the server 440 has a correction amount calculation section 483, a feature amount correction section 481, an analysis section 490, and a modification section 499. The processor 440a of the server 440 realizes these functions by executing the programs stored in the memory 440b.

[0166] The travelling state amount calculation section 495 stabilizes the pressure sensor values (sensor data representing the first pump pressure P1 and the second pump pressure P2) output from the first pressure sensor 13 and the second pressure sensor 23 by a stabilizing filter or the like, and calculates a travelling state amount equivalent to the travel driving force on the basis of the stabilized pressure sensor values.

[0167] The inclination state amount calculation section 496 stabilizes the inclination angle sensor value (sensor data representing the roll angle φ) output from the inclination angle sensor 76 by a stabilizing filter or the like, and calculates an inclination state amount equivalent to the roll angle φ of the machine body 107 on the basis of the stabilized inclination angle sensor value.

[0168] It is necessary to synchronize the travelling state amount and the inclination state amount with each other. Therefore, the characteristics of the stabilizing filters used in the travelling state amount calculation section 495 and the inclination state amount calculation section 496 have equal response characteristics. The travelling state amount calculation section 495 and the inclination state amount calculation section 496 output the travelling state amount and the inclination state amount in synchronization with each other.

[0169] The feature amount computation section 482 computes the travelling feature amount and the inclination feature amount on the basis of the travelling state amount calculated by the travelling state amount calculation section 495, the inclination state amount calculated by the inclination state amount calculation section 496, and the determination result by the state determination section 70. The feature amount computation section 482 extracts, as the travelling feature amount, the travelling state amount calculated at the time when the valid mode is set by the state determination section 70. That is, in the fourth embodiment, the travelling feature amount indicates a travelling state amount to be transmitted to the server 440. Similarly, the feature amount computation section 482 extracts, as the inclination feature amount, the inclination state amount calculated at the time when the valid mode is set by the state determination section 70. That is, in the fourth embodiment, the inclination feature amount indicates an inclination state amount to be transmitted to the server 440.

[0170] The feature amount computation section 482 transmits feature amount data in which the travelling feature amount and the inclination feature amount, the time at which the sensor values used for computing them have been acquired, and a vehicle ID for identifying the hydraulic excavator 400 are associated with each other to the server 440 via the communication device (transmitter) 92. The server 440 acquires feature amount data from each hydraulic excavator 400 via the communication device (receiver) 498.

[0171] The travelling feature amount may be sensor data itself output from the travelling state sensor provided in the hydraulic excavator 400 or calculation data calculated on the basis of the sensor data. Similarly, the inclination feature amount may be sensor data itself output from the inclination state sensor or calculation data calculated on the basis of the sensor data.

[0172] The correction amount calculation section 483 calculates a correction amount related to the travelling feature amount from the inclination feature amount, and outputs it. When each of the inclination state amount and the inclination feature amount is the roll angle φ, the correction amount calculation section 483 calculates the correction amount Pc by the method similar to the method used by the correction amount calculation section 83 of the first embodiment.

[0173] The feature amount correction section 481 corrects the travelling feature amount on the basis of the correction amount Pc and outputs it. When each of the travelling state amount and the travelling feature amount is the differential pressure value ΔP between the first pump pressure P1 and the second pump pressure P2, the feature amount correction section 481 calculates the corrected differential pressure value ΔPc as the abnormality determination evaluation value by the method similar to the method used by the differential pressure value calculation section 81 of the first embodiment.

[0174] The analysis section 490 acquires the corrected differential pressure value ΔPc that is the corrected travelling feature amount and analyzes it. For example, the analysis section 490 makes the abnormality determination by the method similar to the method used by the abnormality determination section 90 described in the first embodiment. When it is determined that there is an abnormality in the travel device 50 or 60, the analysis section 490 outputs the vehicle ID of the hydraulic excavator 400 provided with the travel device 50 or 60 and notification information for informing that an abnormality has occurred in the travel device 50 or 60 to the display device 491 and the sound output device 492.

[0175] The display device 491 displays a notification screen for informing that an abnormality has occurred. The notification screen includes information of the vehicle ID of the hydraulic excavator 400 in which the abnormality has occurred and the travel device (the left travel device 50 or the right travel device 60) in which the abnormality has occurred. The notification screen may include information on the travelling feature amount and the inclination feature amount. The sound output device 492 is, for example, a speaker for outputting the notification information by using voice. It should be noted that the sound output device 492 may be a device for outputting an alarm sound in a preset output pattern according to the notification information.

[0176] Accordingly, the vehicle manager can quickly grasp the hydraulic excavator 400 in which the abnormality has occurred. It should be noted that the analysis section 490 may transmit the notification information via the communication device 498 to the hydraulic excavator 400 in which the abnormality has occurred or an information terminal (for example, a tablet terminal, a smartphone, or a laptop) possessed by the operator of the hydraulic excavator 400.

[0177] The modification section 499 judges the necessity of the modification of the correction amount parameters on the basis of the travelling feature amount, the inclination feature amount, the current correction amount parameter, and the analysis result. The modification section 499 modifies the correction amount parameters when it is judged that the modification of the correction amount parameters is necessary. For example, where a deviation occurs to some extent after checking the appropriateness of the analysis result, the modification section 499 judges that the correction amount parameters need to be altered and adjusted, and performs adjustment processing of the correction amount parameters. For example, the characteristics of the travelling feature amount and the inclination feature amount closer to the true value and matching the actual condition can be obtained by increasing or recalculating the number of data parameters.

[0178] Accordingly, where it is necessary to modify the correction amount parameters, it can be handled by modifying software of the server 440. Accordingly, it is not necessary to conduct work such as modification of software for each of the plurality of hydraulic excavators 400, and the correction amount parameters can be easily modified on the server 440 side. In addition, by only partially modifying the software of the server 440, it is possible to cope with all the hydraulic excavators 400 to be diagnosed, and there is no need to perform rewriting management for each hydraulic excavator 400, which is preferable.

[0179] It should be noted that, although an example in which the server 440 performs automatic modification has been described above, the vehicle manager or the service person may manually modify the correction amount parameters as necessary by using the input device 461.

[0180] As described above, the diagnostic device 480 according to the fourth embodiment is provided with the server 440 provided with the processor (first processor) 440a for diagnosing an abnormality of the travel devices 50 and 60 on the basis of the travelling feature amount (differential pressure value ΔP) representing the travelling states of the travel devices 50 and 60 mounted to the machine body 107 of the hydraulic excavator 400, and the output device (the display device 462 and the communication device 498) for outputting the result of the diagnosis by the processor 440a. The processor 440a acquires the inclination feature amount (roll angle φ) representing the inclination state of the machine body 107. The processor 440a computes the correction amount Pc for canceling the influence of the inclination state of the machine body 107 on the travelling feature amounts (differential pressure value ΔP) of the travel devices 50 and 60 on the basis of the inclination feature amount (roll angle φ). The processor 440a computes the corrected travelling feature amount (corrected differential pressure value ΔPc) by correcting the travelling feature amount (differential pressure value ΔP) on the basis of the correction amount Pc. The processor 440a computes the abnormality determination evaluation value on the basis of the corrected travelling feature amount (corrected differential pressure value ΔPc). The processor 440a determines whether or not there is an abnormality in the travel devices 50 and 60 on the basis of the abnormality determination evaluation value. When it is determined that there is an abnormality, the processor 440a outputs the determination result to the output device (display device 462).

[0181] According to the diagnostic system 410, an abnormality of the hydraulic excavator 400 is diagnosed by the server 440, and an image representing the diagnosis result is output by the display device (output device) 462. Therefore, the vehicle manager can easily identify the hydraulic excavator 400 in which an abnormality has occurred and can quickly and appropriately make a maintenance plan for eliminating the abnormality.

[0182] The diagnostic system 410 according to the fourth embodiment includes the diagnostic device 480 and the hydraulic excavator (work machine) 400. The diagnostic device 480 is provided with the communication device (receiver) 498 and the server 440. The communication device 498 receives the travelling feature amount (differential pressure value ΔP) and the inclination feature amount (roll angle φ) transmitted from the hydraulic excavator 400. The server 440 has the processor (first processor) 440a for diagnosing an abnormality of the travel devices 50 and 60 of the hydraulic excavator 400 on the basis of the travelling feature amount and the inclination feature amount received by the communication device 498, and the non-volatile memory (memory) 402b for storing the correction amount parameters (the loss torque coefficient C and the load characteristic table T) used for computation of the correction amount Pc. The hydraulic excavator 400 is provided with the travelling state sensor (the first pressure sensor 13 and the second pressure sensor 23) for sensing the travelling states of the travel devices 50 and 60, the inclination state sensor (inclination angle sensor 76) for sensing the inclination state of the machine body 107, the processor (second processor) 402a for computing the travelling feature amount (differential pressure value ΔP) on the basis of a sensor value representing the travelling state sensed by the travelling state sensor and computing the inclination feature amount (roll angle φ) on the basis of a sensor value representing the inclination state sensed by the inclination state sensor, and the communication device (transmitter) 92 for transmitting the travelling feature amount (differential pressure value ΔP) and the inclination feature amount (roll angle φ) computed by the processor 402a to the server 440. The processor 402a computes the travelling feature amount (differential pressure value ΔP) and the inclination feature amount (roll angle φ) in synchronization with each other. The processor 440a computes the correction amount Pc on the basis of the correction amount parameters (the loss torque coefficient C and the load characteristic table T) stored in the non-volatile memory 402b and the inclination feature amount (roll angle φ).

[0183] In this configuration, since the correction amount parameters are stored in the server 440, the service person can easily modify the correction amount parameters. In other words, in the present embodiment, it is not necessary for the service person to modify the correction amount parameters in each of the plurality of hydraulic excavators.<Modified example of fourth embodiment>

[0184] In a modified example of the fourth embodiment, a configuration in a case where the communication cycle of data is slow will be described. Various types of communication cycles of data are assumed according to data. For example, where data is transmitted in real time, the communication cycle of the data is set to approximately several tens of Hz. In addition, where daily report data is transmitted, the communication cycle of the data is set to one day. In the modified example of the fourth embodiment, an example suitable for a case where the transmission cycle of data of the hydraulic excavator 400 is long will be depicted.

[0185] In monitoring diagnosis of a machine state such as abnormality diagnosis of the travel device of the hydraulic excavator 400, the condition of the machine body can be sufficiently expressed even if the state is grasped once a day such as a daily report because of being familiar with the daily inspection of the machine body 107. Where the communication cycle of data is approximately once a day, the amount of communication can be largely reduced as compared with a case where data is transmitted in real time. For example, where data is transmitted as a daily report, the data is thinned to one data per day for each item, and the data is transmitted at a frequency of once a day. In this case, the communication cycle from the communication device (transmitter) 92 to the communication device (receiver) 498 is one day (24 hours), and the data on the server 440 side becomes daily down-sampled data.

[0186] On the other hand, there is a demand to perform statistical processing, filter processing, and the like by the analysis section 490 of the server 440 for the purpose of analysis such as confirmation of the behavior and tendency of data such as the acquired feature amount. However, the sampling frequency of data may have an adverse effect (influence of aliasing). Specifically, when sampling a signal, it is necessary to consider the relationship of the Nyquist frequency, and there is a restriction that "only half the sampling frequency can be reproduced." Therefore, in the case of a characteristic including a band to be restricted, it is necessary to perform filtering processing (corresponding to an anti-aliasing filter) for suppressing the influence before down-sampling. The anti-aliasing filter is a low-pass filter that attenuates frequencies above half the sampling frequency with high attenuation characteristics. By sampling a signal having passed through the anti-aliasing filter, the occurrence of aliasing is prevented.

[0187] Fig. 22 is a conceptual diagram for calculating data by down-sampling after applying a filter for feature extraction. The feature amount computation section 482 (see Fig. 21) performs down-sampling after an output value of a filter or the like is appropriately calculated. The feature amount computation section 482 down-samples the output value at three types of cycles. As depicted in Fig. 22, the three types of cycles include a first cycle (hereinafter, a short term) S, a second cycle (hereinafter, a medium term) M, and a third cycle (hereinafter, a long term L), and the magnitude relationship is "short term S < medium term M < long term L."

[0188] As depicted in Fig. 22, a dynamic response for feature extraction from original data is generated and output by a dynamic filter that acquires tendencies in the short term S, the medium term M, and the long term L. Each of these output values is down-sampled as a daily report and output to the server 440. According to the configuration of the modified example of the fourth embodiment, for example, an appropriate value can be calculated even for a behavior in a relatively short term and used for analysis.

[0189] The controller 402 according to the modified example of the fourth embodiment calculates the travelling feature amounts on the basis of sensor data sampled at the respective cycles of the short term S, the medium term M, and the long term L in accordance with a dynamic response characteristic required at the time of analysis, and transmits the respective calculated values to the server 440. It should be noted that since the inclination data is also similarly treated as explanatory variables, the inclination feature amount having the similar response characteristic is calculated and is similarly transmitted as a daily report so that the response is synchronized. That is, the controller 402 calculates the inclination feature amounts on the basis of sensor data sampled at the respective cycles of the short term S, the medium term M, and the long term L, and transmits the respective calculated values to the server 440.

[0190] The controller 402 calculates the travelling feature amount and the inclination feature amount that are synchronized with each other in the short term S and transmits them to the server 440. In addition, the controller 402 calculates the travelling feature amount and the inclination feature amount that are synchronized with each other in the medium term M and transmits them to the server 440. Further, the controller 402 calculates the travelling feature amount and the inclination feature amount that are synchronized with each other in the long term L and transmits them to the server 440.

[0191] Accordingly, in the analysis section 490 of the server 440, the travelling feature amount and the inclination feature amount having a desired response characteristic can be used in a synchronized manner, and thus they can be used as excellent feature amounts without causing phase shift of each data or the like.

[0192] As described above, in the modified example of the fourth embodiment, the processor (second processor) 402a of the hydraulic excavator 400 computes the travelling feature amount and the inclination feature amount for each of the plurality of cycles (the short term S, the medium term M, and the long term L). The processor (first processor) 440a of the server 440 can compute the abnormality determination evaluation value for each of the plurality of cycles (the short term S, the medium term M, and the long term L) on the basis of the travelling feature amount and the inclination feature amount for each of the plurality of cycles (the short term S, the medium term M, and the long term L).

[0193] According to this configuration, the abnormality diagnosis can be performed by using the abnormality determination evaluation value computed on the basis of the travelling feature amount and the inclination feature amount having a desired response characteristic. That is, the convenience of the diagnostic device 480 can be improved.

[0194] According to the configurations of the fourth embodiment and the modified example of the fourth embodiment, since the condition judgement logic can be performed on the server side, the feature amount can be computed and updated regardless of the inclination condition, and the correction amount parameters can be easily adjusted while checking the degree of the feature amount. In addition, the rewriting work or the like of the software of the controller 402 is unnecessary, and the repair work and maintenance management work for the machine body are largely reduced.

[0195] In addition, since it is possible to collect the travelling feature amounts and the inclination feature amounts of the plurality of hydraulic excavators 400 and analyze the behaviors of these feature amounts, it is possible to appropriately and easily set correction conditions such as the necessity of modification of the correction amount parameters and the correction logic (correction method) and the modification amount of the correction parameters. Further, the appropriateness of the setting of the correction conditions can be easily judged by monitoring the behaviors of the travelling feature amounts and the inclination feature amounts collected after the setting of the correction conditions.

[0196] The following modified examples are also within the scope of the present invention, and it is possible to combine the configurations to be depicted in the modified examples with the configurations described in the above embodiments, to combine the configurations described in the above different embodiments with each other, and to combine the configurations to be described in the following different modified examples with each other.<Modified example 1>

[0197] In the first embodiment, the abnormality determination of the travel devices 50 and 60 is executed by performing correction regardless of the roll angle φ of the lower track structure 101. However, if the roll angle φ is too large, there is a risk that the abnormality determination cannot be accurately made even where correction has been performed. Thus, in a modified example 1, the correction processing described in the first embodiment is executed only in a case where the inclination angle is within a predetermined angle range, and the abnormality determination of the travel devices 50 and 60 is performed on the basis of the corrected differential pressure value ΔPc as the abnormality determination evaluation value. The modified example 1 corresponds to an example obtained by combining the first embodiment and the second embodiment with each other.

[0198] Fig. 23 is a diagram similar to those of Fig. 12 and Fig. 15 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by a controller 2 according to the modified example 1. In the flowchart depicted in Fig. 23, the processing of Step S245 of the flowchart of Fig. 15 is added between Step S40 and Step S50 of the flowchart of Fig. 12. The processing of Steps S2 to S40 and Steps S50 to S110 is similar to that of the first embodiment, and the processing of Step S245 is similar to that of the second embodiment.

[0199] Where the absolute value |φ| of the roll angle φ of the lower track structure 101 sensed by the inclination angle sensor 76 is equal to or smaller than the predetermined angle φt and the absolute value |ΔPc| of the corrected differential pressure value ΔPc as the abnormality determination evaluation value is larger than the determination reference value ΔP0, the processor 2a of the controller 2 according to the modified example 1 determines that there is an abnormality in either one of the left travel device 50 and the right travel device 60. Where the absolute value |φ| of the roll angle φ of the lower track structure 101 sensed by the inclination angle sensor 76 is larger than the predetermined angle φt and the absolute value |ΔPc| of the corrected differential pressure value ΔPc as the abnormality determination evaluation value is equal to or smaller than the determination reference value ΔP0, the processor 2a of the controller 2 does not determine that there is an abnormality in either one of the left travel device 50 and the right travel device 60. According to this configuration, it is possible to more appropriately prevent erroneous detection of an abnormality of the travel devices 50 and 60.<Modified example 2>

[0200] Although an example in which the inclination angle sensor 76 is provided in the lower track structure 101 has been described in the second embodiment, the swing structure inclination angle sensor 376a described in the third embodiment may be provided in the upper swing structure 102, and the inclination angle sensor 76 of the lower track structure 101 may be omitted. If the direction (for example, the longitudinal direction) of the upper swing structure 102 is substantially the same as the direction (for example, the longitudinal direction) of the lower track structure 101, the roll angle φswg sensed by the swing structure inclination angle sensor 376a of the upper swing structure 102 can be regarded as the roll angle φtrv of the lower track structure 101.

[0201] Fig. 24 is a diagram similar to that of Fig. 15 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by a controller 202 according to a modified example 2. In the flowchart of Fig. 24, processing of Step S543 is added between Step S40 and Step S245 of the flowchart of Fig. 15.

[0202] As depicted in Fig. 24, when positive determination is made in Step S40, the processing proceeds to Step S543. In Step S543, the controller 202 determines whether or not the swing angle ψ sensed by the swing angle sensor 376b is within a predetermined swing angle range. When the hydraulic excavator 100 is in a reference posture, the swing angle ψ is 0°. The reference posture corresponds to a posture in which the direction of the lower track structure 101 and the direction of the upper swing structure 102 coincide with each other. When the upper swing structure 102 swings to the right from the state of the reference posture, the swing angle ψ increases from 0° to 180° according to the swing. When the upper swing structure 102 swings to the left from the state of the reference posture, the swing angle ψ decreases from 0° to -180° according to the swing (the absolute value increases).

[0203] Where the roll angle φswg of the upper swing structure 102 is set to the roll angle φtrv of the lower track structure 101, the predetermined swing angle range is set to such an angle range that erroneous detection of an abnormality of the travel devices 50 and 60 does not occur. That is, the predetermined swing angle range is set in order to determine that it is in the reference posture, and is set to, for example, -10° or more and +10° or less.

[0204] As described above, the hydraulic excavator 100 according to the modified example 2 is provided with the swing angle sensor 376b for sensing the swing angle ψ of the upper swing structure 102 with respect to the lower track structure 101, and the swing structure inclination angle sensor (the inclination state sensor and the inclination angle sensor) 376a attached to the upper swing structure 102 to sense the roll angle (inclination angle) φ of the upper swing structure 102 with respect to the horizontal plane. It should be noted that, when the directions of the upper swing structure 102 and the lower track structure 101 coincide with each other, the roll angle φswg of the upper swing structure 102 coincides with the roll angle φtrv of the lower track structure 101. The processor 2a of the controller 202 determines whether or not the swing angle ψ sensed by the swing angle sensor 376b is within a predetermined swing angle range (-ψt ≤ ψ ≤ ψt) including the swing angle (0°) at which the direction of the lower track structure 101 and the direction of the upper swing structure 102 coincide with each other. Where the swing angle ψ is within the predetermined swing angle range, the absolute value |φ| of the roll angle (inclination angle) φ of the upper swing structure 102 sensed by the swing structure inclination angle sensor 376a is equal to or smaller than the predetermined angle φt and the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is larger than the determination reference value ΔP0, the processor 2a of the controller 202 determines that there is an abnormality in either one of the left travel device 50 and the right travel device 60. Where the swing angle ψ is not within the predetermined swing angle range or where the absolute value |φ| of the roll angle φ of the upper swing structure 102 is larger than the predetermined angle φt, the processor 2a of the controller 202 does not determine that there is an abnormality in either one of the left travel device 50 and the right travel device 60.

[0205] According to this configuration, since the abnormality determination of the travel devices 50 and 60 can be made by regarding the roll angle φswg of the upper swing structure 102 as the roll angle φtrv of the lower track structure 101, it is not necessary to execute the calculation processing of the track structure roll angle φtrv based on the inclination angles (φswg and θswg) of the upper swing structure 102 and the swing angle ψswg described in the third embodiment. Therefore, it is possible to appropriately make the abnormality determination of the travel devices 50 and 60 while reducing the calculation load.<Modified example 3>

[0206] In the first embodiment, the inclination calculation section 378 may compute the track structure roll angle φ on the basis of the swing structure roll angle φswg, the swing structure pitch angle θswg, and the swing angle ψ as described in the third embodiment.

[0207] In a modified example 3, the inclination angle sensing device (inclination state sensor) 376 includes the swing structure inclination angle sensor 376a that is attached to the upper swing structure 102 to sense the inclination angles (the roll angle φswg and the pitch angle θswg) of the upper swing structure 102 with respect to the horizontal plane, the swing angle sensor 376b that senses the swing angle ψ of the upper swing structure 102 with respect to the lower track structure 101, and the inclination calculation section (computation device) 378 that computes the roll angle φtrv, which is an inclination angle in the lateral direction of the lower track structure 101 with respect to the horizontal plane, on the basis of the inclination angles (the roll angle φswg and the pitch angle θswg) of the upper swing structure 102 sensed by the swing structure inclination angle sensor 376a and the swing angle ψ of the upper swing structure 102 sensed by the swing angle sensor 376b. The processor 2a of the controller 2 computes the correction amount Pc on the basis of the roll angle φtrv of the lower track structure 101.

[0208] According to this configuration, in addition to the action and effect similar to those in the first embodiment, it is possible to simplify the configuration of the hydraulic excavator 100 and reduce the manufacturing cost by omitting the installation of the inclination angle sensor in the lower track structure 101.<Modified example 4>

[0209] In the above embodiments, an examples in which the differential pressure value (the second embodiment and the third embodiment) and the corrected differential pressure value (the first embodiment and the fourth embodiment) are employed as the abnormality determination evaluation values has been described, but the present invention is not limited thereto. The integrated value of the differential pressure values and the integrated value of the corrected differential pressure values may be employed as the abnormality determination evaluation values. For example, in the second embodiment, after the processing of Step S2 in Fig. 15, the controller 202 adds a plurality of differential pressure values calculated in the past Step S2 to the differential pressure value calculated in Step S2 to compute the integrated value of a certain number (for example, N pieces) of differential pressure values. In Step S250, the controller 202 extracts the integrated value of the differential pressure values as the abnormality determination evaluation value. It should be noted that a value (ΔP0 × N) obtained by multiplying the determination reference value described in the second embodiment by a certain number (for example, N pieces) is set to a determination reference value ΔP0' to be compared with the integrated value of the differential pressure values (ΔP0' = ΔP0 × N). The upper limit value Pu corresponds to ΔP0' (Pu = ΔP0') and the lower limit value Pl corresponds to -ΔP0' (Pl = -ΔP0').

[0210] By using the differential pressure integrated value as the abnormality determination evaluation value, the influence of the road surface conditions can be eliminated and an abnormality of the left and right travel devices 50 and 60 can be appropriately sensed.<Modified example 5>

[0211] The low-pass filter processing may be performed on the first pump pressure P1 sensed by the first pressure sensor 13 and the second pump pressure P2 sensed by the second pressure sensor 23, and the abnormality determination evaluation value may be calculated on the basis of the differential pressure value between the first pump pressure P1 and the second pump pressure P2 after the low-pass filter processing. The low-pass filter processing removes pressure fluctuations in the first pump pressure P1 and the second pump pressure P2 that occur when the left and right travel devices 50 and 60 accelerate, and moving average processing is cited as an example.

[0212] When the controller performs the low-pass filter processing on the respective pressure values from the first pressure sensor 13 and the second pressure sensor 23, the transitional fluctuation components included in the respective pressure values are removed, and thus the abnormality determination accuracy of the left and right travel devices 50 and 60 can be maintained in an unsteady travelling state such as a state during acceleration.<Modified example 6>

[0213] Although an example in which the work machine is the hydraulic excavator 100 has been described in the above embodiments, the present invention is not limited thereto. The present invention is applicable to various work machines provided with the hydraulically-driven or electrically-driven left travel device 50 and right travel device 60.

[0214] Although the embodiments of the present invention have been described above, the above-described embodiments merely depict some application examples of the present invention, and it is not intended to limit the technical scope of the present invention to the specific configurations of the above-described embodiments.Description of Reference Characters

[0215] 1: engine 2: controller 2a: processor (first processor) 2b: non-volatile memory (memory) 3: work operation sensor 4: swing operation sensor 5: travelling operation sensor 6: travelling lever device (travelling operation device) 11: first hydraulic pump 13: first pressure sensor (travelling state sensor) 21: second hydraulic pump 23: second pressure sensor (travelling state sensor) 31: left travelling motor (hydraulic motor, hydraulic actuator) 32: right travelling motor (hydraulic motor, hydraulic actuator) 33: boom cylinder (hydraulic actuator) 34: arm cylinder (hydraulic actuator) 35: bucket cylinder (hydraulic actuator) 36: swing motor (hydraulic actuator) 37: actuator for attachment (hydraulic actuator) 50: left travel device 51: travel drive system 60: right travel device 61: travel drive system 70: state determination section 76: inclination angle sensor (inclination state sensor) 80: diagnostic device 81: differential pressure value calculation section 82: effective differential pressure value extraction section 83: correction amount calculation section 90: abnormality determination section 91: display device (output device) 92: communication device (output device, transmitter) 100: hydraulic excavator (work machine) 101: lower track structure 102: upper swing structure 103: work device 107: machine body 110: operation room 200: hydraulic drive system 202: controller 277: inclination state determination section 281: differential pressure value calculation section 282: effective differential pressure value extraction section 290: abnormality determination section 302: controller 376: inclination angle sensing device 376a: swing structure inclination angle sensor (inclination state sensor, inclination angle sensor) 376b: swing angle sensor 377: inclination state determination section 378: inclination calculation section (computation device) 400: hydraulic excavator 402: controller 402a: processor (second processor) 410: diagnostic system 440: server 440a: processor (first processor) 440b: non-volatile memory (memory) 461: input device 462: display device (output device) 480: diagnostic device 481: feature amount correction section 482: feature amount computation section 483: correction amount calculation section 490: analysis section 491: display device (output device) 492: sound output device (output device) 495: travelling state amount calculation section 496: inclination state amount calculation section 498: communication device (output device, receiver) FL, FR: load G: centroid position P1: first pump pressure P2: second pump pressure Pc: correction amount Pc1: first correction amount Pc2: second correction amount Pl: lower limit value (negative determination reference value) Pu: upper limit value (positive determination reference value) ΔP: differential pressure value (abnormality determination evaluation value) ΔP0: determination reference value ΔPc: corrected differential pressure value (abnormality determination evaluation value) θ, θtrv: track structure pitch angle θswg: swing structure pitch angle φ, φtrv: track structure roll angle φswg: swing structure roll angle ψ: swing angle φt: allowable roll angle (predetermined angle) ψ: swing angle

Examples

first embodiment

[0010]Fig. 1 is a side view of a hydraulic excavator 100 according to the present invention.

[0011]As depicted in Fig. 1, the hydraulic excavator 100 is provided with a lower track structure 101, an upper swing structure 102 swingably provided with respect to the lower track structure 101, and a work device 103 attached to the front side of the upper swing structure 102. The lower track structure 101 and the upper swing structure 102 configure a machine body 107 of the hydraulic excavator 100.

[0012]The work device 103 is provided with a boom 104 attached to a right front portion of the upper swing structure 102 so as to be rotatable in the vertical direction, an arm 105 attached to a tip end portion of the boom 104 so as to be rotatable in the vertical and longitudinal directions, a bucket 106 attached to a tip end portion of the arm 105 so as to be rotatable in the vertical and longitudinal directions, a boom cylinder 33 as a hydraulic actuator for driving the boom 104, an arm cylin...

second embodiment

[0132]As described above, in the second embodiment, when the absolute value of the roll angle φ (the magnitude of the roll angle φ) of the lower track structure 101 is larger than the predetermined angle φt, the abnormality determination processing is not executed because the abnormality determination processing is affected. The predetermined angle φt is a threshold value of the roll angle φ for determining whether or not the inclination state affects the abnormality determination processing of the travel devices 50 and 60. The predetermined angle φt corresponds to the roll angle φ of, for example, ±10% (in the present embodiment, -10%) with respect to the balanced load when there is no inclination (φ = 0°). Therefore, the abnormality determination processing is executed only in a case where the change in the load due to inclination is within ±10%.

[0133]According to the second embodiment described above, the following action and effect are exhibited.

[0134]The processor 2a of the con...

third embodiment

[0149]Fig. 19 is a diagram similar to that of Fig. 15 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller 302 according to the In the flowchart of Fig. 19, processing of Step S307 is added between Step S2 and Step S10 of the flowchart of Fig. 15.

[0150]As depicted in Fig. 19, when the differential pressure calculation processing (Step S2) is terminated, the processing proceeds to Step S307. In Step S307, the inclination state determination section 377 acquires the track structure roll angle φ calculated by the inclination calculation section 378. It should be noted that the inclination calculation section 378 acquires the swing structure roll angle φswg, the swing structure pitch angle θswg, and the swing angle ψ sensed by the inclination angle sensing device 376 at a predetermined computation cycle, calculates the track structure roll angle φtrv, and outputs it to the controller 302.

[0151]According to the third ...

Technical Field

[0001] The present invention relates to a diagnostic device, a work machine provided with the diagnostic device, and a diagnostic system.Background Art

[0002] Patent Document 1 discloses a work machine provided with a controller for controlling the capacities of a first hydraulic pump and a second hydraulic pump according to an operation of a travelling operation device. The controller of the work machine calculates an abnormality determination evaluation value on the basis of a pressure difference between the pressure of the first hydraulic pump and the pressure of the second pump, and determines that there is an abnormality in either one of a left travel device and a right travel device on the basis of a comparison result between the abnormality determination evaluation value and a predetermined determination reference value.Prior Art DocumentPatent Documents

[0003] Patent Document 1: JP-2019-049102-ASummary of the InventionProblem to be Solved by the Invention

[0004] However, the pressure of the first hydraulic pump and the pressure of the second hydraulic pump used for determination of an abnormality are affected by the inclination of a travelling road surface. Therefore, in the invention described in Patent Document 1, there is a risk that an abnormality of the travel device is erroneously detected if the travelling road surface is inclined.

[0005] An object of the present invention is to prevent erroneous detection of an abnormality of a travel device when travelling on an inclined road surface and to appropriately detect an abnormality of the travel device.Means for Solving the Problem

[0006] A diagnostic device according to an aspect of the present invention includes: a first processor for diagnosing an abnormality of a travel device on the basis of a travelling feature amount representing a travelling state of the travel device mounted to a machine body of a work machine and an output device for outputting a result of a diagnosis performed by the first processor. The first processor is configured to: acquire an inclination feature amount representing an inclination state of the machine body; compute a correction amount for canceling an influence of the inclination state of the machine body on the travelling feature amount of the travel device on the basis of the inclination feature amount; compute a corrected travelling feature amount by correcting the travelling feature amount on the basis of the correction amount; compute an abnormality determination evaluation value on the basis of the corrected travelling feature amount; determine whether or not there is an abnormality in the travel device on the basis of the abnormality determination evaluation value, and output, when it is determined that there is an abnormality, relevant determination result to the output device.Advantages of the Invention

[0007] According to the present invention, it is possible to prevent erroneous detection of an abnormality of a travel device when travelling on an inclined road surface and to appropriately detect an abnormality of the travel device.Brief Description of the Drawings

[0008] [Fig. 1] Fig. 1 is a side view of a hydraulic excavator according to a first embodiment of the present invention. [Fig. 2] Fig. 2 is a perspective view of a lower track structure depicted in Fig. 1. [Fig. 3] Fig. 3 is an outline configuration diagram of a hydraulic drive system mounted on the hydraulic excavator depicted in Fig. 1. [Fig. 4] Fig. 4 is a diagram for depicting a travel drive system of the hydraulic excavator. [Fig. 5] Fig. 5 is a diagram for depicting a machine body coordinate system of the hydraulic excavator and a rotation angle of the hydraulic excavator (lower track structure). [Fig. 6] Fig. 6 is a schematic rear view of the hydraulic excavator and depicts a case where a travelling road surface is a horizontal road surface parallel to the horizontal direction. [Fig. 7] Fig. 7 is a schematic rear view of the hydraulic excavator and depicts a case where a travelling road surface is an inclined road surface inclined with respect to the horizontal direction. [Fig. 8] Fig. 8 is a diagram for depicting characteristics of a roll angle φ and loads FL and FR applied to left and right travel devices, respectively. [Fig. 9] Fig. 9 is a rear view of the hydraulic excavator and is a diagram for depicting an attachment position of an inclination angle sensing device. [Fig. 10] Fig. 10 is a functional block diagram of a controller according to the first embodiment. [Fig. 11] Fig. 11 is a diagram for explaining details of correction logic by a differential pressure value calculation section and a correction amount calculation section. [Fig. 12] Fig. 12 is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller according to the first embodiment. [Fig. 13] Fig. 13 is a functional block diagram of a controller according to a second embodiment. [Fig. 14] Fig. 14 is a diagram for depicting an allowable load difference and an allowable roll angle range. [Fig. 15] Fig. 15 is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller according to the second embodiment. [Fig. 16] Fig. 16 is a schematic view for depicting inclination angles (a roll angle φtrv and a pitch angle θtrv) of the lower track structure and inclination angles (a roll angle φswg and a pitch angle θswg) of an upper swing structure. [Fig. 17] Fig. 17 depicts graphs for depicting the relationship between a swing angle ψ and the roll angle φtrv of the lower track structure and the relationship between the swing angle ψ and the pitch angle θtrv of the lower track structure when the roll angle φswg of the upper swing structure is 10°. [Fig. 18] Fig. 18 is a functional block diagram of a controller according to a third embodiment. [Fig. 19] Fig. 19 is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller according to the third embodiment. [Fig. 20] Fig. 20 is a diagram for depicting a configuration of a diagnostic system according to a fourth embodiment. [Fig. 21] Fig. 21 is a functional block diagram of the diagnostic system according to the fourth embodiment. [Fig. 22] Fig. 22 is a conceptual diagram for calculating data by down-sampling after applying a filter for feature extraction. [Fig. 23] Fig. 23 is a flowchart for depicting an example of the flow of abnormality determination processing executed by a controller according to a modified example 1. [Fig. 24] Fig. 24 is a flowchart for depicting an example of the flow of abnormality determination processing executed by a controller according to a modified example 2. Modes for Carrying Out the Invention

[0009] Hereinafter, a hydraulic work machine according to embodiments of the present invention will be described with reference to the drawings by taking a hydraulic excavator as an example. It should be noted that in the drawings, the same reference numerals are given to equivalent members, and redundant descriptions are appropriately omitted.<First Embodiment>

[0010] Fig. 1 is a side view of a hydraulic excavator 100 according to a first embodiment of the present invention.

[0011] As depicted in Fig. 1, the hydraulic excavator 100 is provided with a lower track structure 101, an upper swing structure 102 swingably provided with respect to the lower track structure 101, and a work device 103 attached to the front side of the upper swing structure 102. The lower track structure 101 and the upper swing structure 102 configure a machine body 107 of the hydraulic excavator 100.

[0012] The work device 103 is provided with a boom 104 attached to a right front portion of the upper swing structure 102 so as to be rotatable in the vertical direction, an arm 105 attached to a tip end portion of the boom 104 so as to be rotatable in the vertical and longitudinal directions, a bucket 106 attached to a tip end portion of the arm 105 so as to be rotatable in the vertical and longitudinal directions, a boom cylinder 33 as a hydraulic actuator for driving the boom 104, an arm cylinder 34 as a hydraulic actuator for driving the arm 105, and a bucket cylinder 35 as a hydraulic actuator for driving the bucket 106.

[0013] An operation room 110 is provided at a left front portion of the upper swing structure 102. In the operation room 110, left and right travelling lever devices 6 and 7 (see Fig. 4) as travelling operation devices for operating the lower track structure 101, left and right operation lever devices 8 and 9 (see Fig. 4) as work operation devices for operating the upper swing structure 102 and the work device 103, and the like are arranged.

[0014] An enclosure (engine room) in which hydraulic equipment such as a first hydraulic pump 11 and a second hydraulic pump 21 (see Fig. 3) and an engine 1 (see Fig. 3) are mounted is provided behind the operation room 110.

[0015] As depicted in Fig. 4, the left travelling lever device 6 has a left travelling lever 6a for operating a left travelling motor 31. The right travelling lever device 7 has a right travelling lever 7a for operating a right travelling motor 32. The left operation lever device 8 has a left operation lever 8a for operating the arm cylinder 34 and a swing motor 36 (see Fig. 3). The right operation lever device 9 has a right operation lever 9a for operating the boom cylinder 33 and the bucket cylinder 35.

[0016] Fig. 2 is a perspective view of the lower track structure 101 depicted in Fig. 1.

[0017] As depicted in Fig. 2, the lower track structure 101 is provided with a track frame 41 and left and right travel devices 50 and 60 provided on the left and right sides of the track frame 41, respectively. The left and right travel devices 50 and 60 are provided with left and right travel drive systems 51 and 61, left and right crawlers (track links and shoes) 52 and 62 driven by the left and right travel drive systems 51 and 61, left and right front idlers 53 and 63 for supporting the left and right crawlers 52 and 62, and left and right vertical rollers (not depicted), respectively.

[0018] The left travel drive system 51 is provided with the left travelling motor 31 (see Fig. 3) including a hydraulic motor, a travelling reduction gear 54 (see Fig. 3) for reducing the rotation of the left travelling motor 31 and transmitting the reduced rotation to the crawler, and a brake valve 55 (see Fig. 4) for braking the left travelling motor 31. Similarly, the right travel drive system 61 is provided with the right travelling motor 32 (see Fig. 3) including a hydraulic motor, a travelling reduction gear 64 (see Fig. 3) for reducing the rotation of the right travelling motor 32 and transmitting the reduced rotation to the crawler, and a brake valve 65 (see Fig. 4) for braking the right travelling motor 32.

[0019] A swing ring 42 for swingably coupling the upper swing structure 102 is provided at an upper portion of the track frame 41. A center joint 43 for circulating hydraulic fluid between the lower track structure 101 and the upper swing structure 102 is arranged at the center position of the swing ring 42. The left and right travel drive systems 51 and 61 and the center joint 43 are connected to each other by pipes 44.

[0020] Fig. 3 is an outline configuration diagram of a hydraulic drive system 200 mounted on the hydraulic excavator 100 depicted in Fig. 1.

[0021] As depicted in Fig. 3, the hydraulic drive system 200 is provided with the engine 1 as a prime mover, the first hydraulic pump 11 driven by the engine 1, the second hydraulic pump 21 driven by the engine 1, a first control valve unit 12 for controlling the flow of hydraulic operating fluid supplied from the first hydraulic pump 11 to a plurality of hydraulic actuators (the left travelling motor 31, the arm cylinder 34, the swing motor 36, and an actuator for attachment 37) including the left travelling motor 31, and a second control valve unit 22 for controlling the flow of hydraulic operating fluid supplied from the second hydraulic pump 21 to a plurality of hydraulic actuators (the right travelling motor 32, the boom cylinder 33, and the bucket cylinder 35) including the right travelling motor 32.

[0022] The first control valve unit 12 and the second control valve unit 22 are multiple directional control valves each having a plurality of directional control valves. The first control valve unit 12 has a directional control valve for left travelling 12a that controls the flow of hydraulic fluid between the first hydraulic pump 11 and the left travelling motor 31. The second control valve unit 22 has a directional control valve for right travelling 22a that controls the flow of hydraulic fluid between the second hydraulic pump 21 and the right travelling motor 32.

[0023] Fig. 4 is a diagram for depicting a travel drive system of the hydraulic excavator 100.

[0024] As depicted in Fig. 4, the travel drive system of the travel device of the left (hereinafter, also referred to as a left travel device) 50 is provided with the left travelling motor 31 driven by hydraulic fluid supplied from the first hydraulic pump 11, the directional control valve for left travelling 12a for controlling the flow of the hydraulic fluid supplied from the first hydraulic pump 11 to the left travelling motor 31, and the left brake valve 55 provided in a hydraulic line connecting the directional control valve for left travelling 12a and the left travelling motor 31 to each other. The travel drive system of the travel device of the right (hereinafter, also referred to as a right travel device) 60 is provided with the right travelling motor 32 driven by hydraulic fluid supplied from the second hydraulic pump 21, the directional control valve for right travelling 22a for controlling the flow of the hydraulic fluid supplied from the second hydraulic pump 21 to the right travelling motor 32, and the right brake valve 65 provided in a hydraulic line connecting the directional control valve for right travelling 22a and the right travelling motor 32 to each other.

[0025] The first hydraulic pump 11 and the second hydraulic pump 21 are variable displacement hydraulic pumps. The first hydraulic pump 11 is provided with a pump regulator 11a for adjusting the delivery capacity (displacement volume per one revolution) of the first hydraulic pump 11. The second hydraulic pump 21 is provided with a pump regulator 21a for adjusting the delivery capacity (displacement volume per one revolution) of the second hydraulic pump 21.

[0026] The hydraulic excavator 100 is provided with a first pressure sensor 13, a second pressure sensor 23, a work operation sensor 3, a swing operation sensor 4, a travelling operation sensor 5, and a controller 2. The first pressure sensor 13 is provided in a hydraulic line connecting the first hydraulic pump 11 and the first control valve unit 12 to each other. The first pressure sensor 13 senses a first pump pressure P1 that is the delivery pressure of the first hydraulic pump 11, and outputs a signal (sensor value) representing the sensed result to the controller 2. The second pressure sensor 23 is provided in a hydraulic line connecting the second hydraulic pump 21 and the second control valve unit 22 to each other. The second pressure sensor 23 senses a second pump pressure P2 that is the delivery pressure of the second hydraulic pump 21, and outputs a signal (sensor value) representing the sensed result to the controller 2. The first pump pressure P1 is a travelling state amount representing the travelling state (travel driving force) of the left travel device 50, and the second pump pressure P2 is a travelling state amount representing the travelling state (travel driving force) of the right travel device 60. Therefore, the first pressure sensor 13 and the second pressure sensor 23 function as travelling state sensors for sensing the travelling states of the travel devices 50 and 60.

[0027] The work operation sensor 3 senses operations (work operations) of the boom cylinder 33, the arm cylinder 34, and the bucket cylinder 35 operated by an operator, and outputs work operation signals representing the sensed results to the controller 2. The swing operation sensor 4 senses an operation (swing operation) of the swing motor 36 operated by the operator and outputs a swing operation signal representing the sensed result to the controller 2. The travelling operation sensor 5 senses operations (travelling operations) of the left and right travelling motors 31 and 32 operated by the operator, and outputs travelling operation signals representing the sensed results to the controller 2.

[0028] The controller 2 is configured with a computer provided with a processor 2a such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or a DSP (Digital Signal Processor), a non-volatile memory 2b such as a ROM (Read Only Memory), a flash memory, or a hard disk drive, a volatile memory 2c what is called a RAM (Random Access Memory), an input interface 2d, an output interface 2e, and other peripheral circuits. These pieces of hardware cooperate with each other to operate software and realize a plurality of functions. It should be noted that the controller 2 may be configured with one computer or a plurality of computers. In addition, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), or the like can be used as the processor 2a.

[0029] The non-volatile memory 2b stores programs capable of executing various computations. That is, the non-volatile memory 2b is a storage medium (storage device) capable of reading programs for realizing the functions of the present embodiment. The volatile memory 2c is a storage medium (storage device) for temporarily storing a computation result computed by the processor 2a and a signal input from the input interface 2d. The processor 2a is a device for expanding the program stored in the non-volatile memory 2b into the volatile memory 2c to execute a computation, and performs predetermined computation processing on data taken in from the input interface 2d, the non-volatile memory 2b, and the volatile memory 2c in accordance with the program.

[0030] The input interface 2d converts signals input from various devices (the pressure sensors 13 and 23, the operation sensors 3, 4, and 5, and the like) into data that can be computed by the processor 2a. In addition, the output interface 2e generates an output signal according to the computation result of the processor 2a, and outputs the signal to various devices (the pump regulators 11a and 21a and the like).

[0031] The controller 2 calculates target delivery flow rates of the first hydraulic pump 11 and the second hydraulic pump 21 on the basis of the sensed results of the work operation sensor 3, the swing operation sensor 4, and the travelling operation sensor 5. The controller 2 calculates target capacities (target delivery capacities) of the first hydraulic pump 11 and the second hydraulic pump 21 on the basis of the calculated target delivery flow rates, and outputs command signals according to the calculated target capacities to the pump regulators 11a and 21a. Accordingly, the delivery flow rates of the first hydraulic pump 11 and the second hydraulic pump 21 are controlled so as to coincide with the respective target delivery flow rates. For example, the controller 2 increases the target capacity of the first hydraulic pump 11 as the operation amount of the left travelling lever device 6 increases. In addition, for example, the controller 2 increases the target capacity of the second hydraulic pump 21 as the operation amount of the right travelling lever device 7 increases.

[0032] In the present embodiment, a diagnostic device 80 for diagnosing an abnormality of the travel devices 50 and 60 is mounted on the hydraulic excavator 100. The diagnostic device 80 includes the controller 2 and an output device (a display device 91 and a communication device 92) mounted on the hydraulic excavator 100. The controller 2 diagnoses an abnormality of the left and right travel devices 50 and 60 when the hydraulic excavator 100 is in a predetermined operation state on the basis of the operation amounts sensed by the operation sensors 3 to 5, the first pump pressure P1 sensed by the first pressure sensor 13, and the second pump pressure P2 sensed by the second pressure sensor 23. The result of the diagnosis is output by the display device 91 and the communication device 92 as the output device.

[0033] Incidentally, the first pump pressure P1 and the second pump pressure P2 used for the abnormality diagnosis are affected by the inclination of a travelling road surface. Hereinafter, the causes that affect the first pump pressure P1 and the second pump pressure P2 on a slope will be described.

[0034] Fig. 5 is a diagram for depicting a machine body coordinate system of the hydraulic excavator 100 and a rotation angle of the hydraulic excavator 100 (lower track structure 101).

[0035] As depicted in Fig. 5, for example, the machine body coordinate system that is a coordinate system using the lower track structure 101 as a reference is set to the hydraulic excavator 100. The machine body coordinate system is defined as a right-handed coordinate system using as the origin an arbitrary point on the swing centerline that is the rotation axis of the upper swing structure 102. In the machine body coordinate system, the forward direction of the lower track structure 101 is defined as the positive direction of the X axis. In the machine body coordinate system, the vertically upper direction along the swing centerline is defined as the positive direction of the Z axis. In the machine body coordinate system, the left direction of the lower track structure 101 orthogonal to each of the X axis and the Z axis is defined as the positive direction of the Y axis.

[0036] Rotation in the X-Z plane orthogonal to the Y axis is called pitching, and the rotation angle thereof is represented by a pitch angle θ. Rotation in the X-Y plane orthogonal to the Z axis is called yawing, and the rotation angle thereof is represented by a yaw angle ψ. Rotation in the Y-Z plane orthogonal to the X axis is called rolling, and the rotation angle thereof is represented by a roll angle φ. The X axis is an axis along the advancing direction of the lower track structure 101, and the roll angle φ with the X-axis as the rotation axis corresponds to the lateral inclination angle of the lower track structure 101 with respect to a horizontal plane. Here, the horizontal plane means a virtual plane orthogonal to the gravity direction (vertical direction).

[0037] Fig. 6 and Fig. 7 are schematic rear views of the hydraulic excavator 100. In the drawings, loads acting on the hydraulic excavator 100 are schematically indicated by arrows. Fig. 6 depicts a case where a travelling road surface 109 is a horizontal road surface 109a parallel to the horizontal direction, and Fig. 7 depicts a case where the travelling road surface 109 is an inclined road surface 109b inclined with respect to the horizontal direction. The horizontal direction is the direction orthogonal to the direction of gravity (vertical direction). That is, the roll angle φ is 0° (φ = 0).

[0038] As depicted in Fig. 6, where the hydraulic excavator 100 travels on the horizontal road surface 109a, a load (reaction force) equally acts on each of the left travel device 50 and the right travel device 60 from the ground. That is, a load FL acting on the left travel device 50 is equal to a load FR acting on the right travel device 60. In addition, the loads FL and FR acting on the travel device 50 are half of the deadweight F of the hydraulic excavator 100 (FL = FR = 1 / 2 × F). As depicted in Fig. 6, the posture of the hydraulic excavator 100 when the hydraulic excavator 100 is not inclined is referred to as a horizontal posture. In addition, an intersection point between the swing center axis of the hydraulic excavator 100 in the horizontal posture and the travelling road surface 109 is defined as a reference point O.

[0039] As depicted in Fig. 7, where the hydraulic excavator 100 travels on the inclined road surface 109b in a state of being inclined to the left and right, the load (reaction force) received by the left travel device 50 from the ground and the load (reaction force) received by the right travel device 60 from the ground are different from each other in magnitude (FL ≠ FR). The load acting on the hydraulic excavator 100 will be specifically described with reference to Fig. 7.

[0040] The roll angle (φ of the lower track structure 101 travelling on the inclined road surface 109b is not 0° (φ ≠ 0). In the illustrated example, the left travel device 50 is positioned on the lower side than the right travel device 60. That is, the height of the left travel device 50 is lower than the height of the right travel device 60. Here, the height means a distance in the vertical direction from the horizontal reference plane to the travel device 50 or 60. In addition, as depicted in Fig. 7, the posture of the hydraulic excavator 100 when the hydraulic excavator 100 is inclined to the left or right is referred to as an inclined posture.

[0041] In the horizontal posture depicted in Fig. 6, the centroid position G of the hydraulic excavator 100 is positioned near the centerline of the hydraulic excavator 100 in the lateral width direction. In the inclined posture depicted in Fig. 7, the centroid position G of the hydraulic excavator 100 moves toward the left travel device 50 having a relatively low height between the left and right travel devices 50 and 60 as compared with the horizontal posture (see Fig. 6). Specifically, the centroid position G is positioned on the left side relative to the reference point O. As a result, the load FL acting on the left travel device 50 is larger than the load FR acting on the right travel device 60.

[0042] The load FR acting on the right travel device 60 is calculated by the following equation (1). The load FL acting on the left travel device 50 is calculated by the following equation (2). FR = 1 / 2 − h / B × tanφ × F FL = 1 / 2 + h / B × tanφ × F

[0043] F is the gravity acting on the hydraulic excavator 100. The roll angle φ is the inclination angle of the travelling road surface 109 from the horizontal plane (reference plane). B is the distance from the center of the crawler of the left travel device 50 to the center of the crawler of the right travel device 60, and is hereinafter referred to as a crawler width. In each equation, h is the height from the travelling road surface 109 to the centroid position G (h > 0). That is, the height h corresponds to the distance from the centroid position G to the travelling road surface 109 in a perpendicular line from the centroid position G to the travelling road surface 109.

[0044] The crawler width B, the height h, and the roll angle φ satisfy the following equation (3). − B / 2 h ≤ tanφ ≤ B / 2 h

[0045] Where the travelling road surface 109 is inclined, the load acting on the travel device positioned at a higher position becomes smaller as compared with when the travelling road surface 109 is horizontal. Conversely, the load acting on the travel device positioned at a lower position becomes larger.

[0046] Fig. 8 is a diagram for depicting characteristics of the roll angle φ and the loads FL and FR applied to the left and right travel devices 50 and 60, respectively.

[0047] As depicted in Fig. 8, when the hydraulic excavator 100 is in the horizontal posture, the roll angle φ is 0°. When the hydraulic excavator 100 is in the inclined posture in which the left travel device 50 is positioned on the lower side and the right travel device 60 is positioned on the upper side, the roll angle φ has a positive value. When the hydraulic excavator 100 is in the inclined posture in which the right travel device 60 is positioned on the lower side and the left travel device 50 is positioned on the upper side, the roll angle φ has a negative value. As the roll angle φ becomes larger from 0°, the load FL acting on the left travel device 50 becomes larger and the load FR acting on the right travel device 60 becomes smaller. Conversely, as the roll angle becomes smaller from 0° (becomes larger in the negative direction), the load FR acting on the right travel device 60 becomes larger and the load FL acting on the left travel device 50 becomes smaller.

[0048] Where the hydraulic excavator 100 travels in the inclined posture, the loads acting on the left and right travel devices 50 and 60 change from those in the horizontal posture as described above. Accordingly, the loads acting on driving portions, sliding portions, and the like configuring the travel drive systems 51 and 61 change from those in the horizontal posture. In the inclined posture, frictional force and travelling resistance (loss force) with respect to the ground change from those in the horizontal posture, and the driving force necessary for travel driving of the hydraulic excavator 100 changes. For example, in the inclined posture in which the left travel device 50 is positioned at a positioned lower than the right travel device 60, the amount of the left travel device 50 sinking into the ground becomes larger than that in the horizontal posture. As a result, the road surface resistance acting on the left travel device 50 from the ground becomes larger than that in the horizontal posture. That is, the driving force necessary for travel driving of the left travel device 50 in the inclined posture becomes larger compared with that in the horizontal posture. As a result, the driving pressure of the left travelling motor 31 (the delivery pressure of the first hydraulic pump 11) becomes larger compared with that in the horizontal posture.

[0049] As described above, there is a case where the driving force necessary for travel driving changes due to a change in the loads acting on the left and right travel devices 50 and 60. Therefore, in the present embodiment, in order to appropriately diagnose an abnormality of the travel devices 50 and 60, parameters used for abnormality diagnosis are corrected according to the inclination state of the machine body 107.

[0050] Fig. 9 is a rear view of the hydraulic excavator 100 and is a diagram for depicting an attachment position of an inclination angle sensor 76.

[0051] In the present embodiment, the inclination angle sensor 76 is attached to the track frame 41 of the lower track structure 101 as depicted in Fig. 9 in order to grasp the inclination state of the machine body 107. The inclination angle sensor 76 senses the roll angle φ that is the lateral inclination angle of the lower track structure 101 with respect to the horizontal plane, and outputs a signal (sensor value) representing the sensed result to the controller 2. The controller 2 can grasp the inclination state (rolled state) of the hydraulic excavator 100 on the basis of the sensed result of the inclination angle sensor 76. The inclination angle sensor 76 can employ an IMU (Inertial Measurement Unit) that acquires angular velocities and accelerations of orthogonal three axes as information related to the posture of the lower track structure 101, computes the roll angle φ of the lower track structure 101 on the basis of this information, and outputs a signal representing the roll angle φ to the controller 2. The roll angle φ is an inclination state amount representing the inclination state of the machine body 107 with respect to the horizontal plane. Therefore, the inclination angle sensor 76 functions as an inclination state sensor for sensing the inclination state of the machine body 107 with respect to the horizontal plane.

[0052] Fig. 10 is a functional block diagram of the controller 2.

[0053] The display device 91 such as a liquid crystal monitor installed in the operation room 110, and the communication device 92 installed in an outer frame or the like of the operation room 110 are connected to the controller 2. The display device 91 is an output device that is controlled by the controller 2 and outputs the computation result of the controller 2 as an image. The communication device 92 is a wireless communication device capable of wirelessly communicating with a wireless base station connected to a communication line, and has a communication interface including a communication antenna using a band such as a 2.1 GHz band as a sensitive band. The communication device 92 exchanges information with a server 40 or the like via a communication line. The communication device 92 is an output device that is controlled by the controller 2 and outputs communication data representing the computation result of the controller 2. The server 40 is installed in, for example, a management facility apart from the work site of the hydraulic excavator 100. A vehicle manager and a service person can manage various vehicles that conduct work at the work site on the basis of operation information of the various vehicles (the hydraulic excavator and the like) displayed on a display device such as a liquid crystal monitor connected to the server 40.

[0054] The controller 2 is provided with a differential pressure value calculation section 81, an effective differential pressure value extraction section 82, a correction amount calculation section 83, a state determination section 70, and an abnormality determination section 90. The processor 2a of the controller 2 realizes these functions by executing the programs stored in the non-volatile memory 2b. The state determination section 70 determines whether or not a travelling single operation is being performed on the basis of the travelling operation signal from the travelling operation sensor 5, the work operation signal from the work operation sensor 3, and the swing operation signal from the swing operation sensor 4.

[0055] The state determination section 70 determines whether or not the hydraulic excavator 100 is travelling straight ahead on the basis of a first tilting command value that is a tilting command value of the first hydraulic pump 11 and a second tilting command value that is a tilting command value of the second hydraulic pump 21. When the difference between the first tilting command value and the second tilting command value is equal to or smaller than a volume difference threshold value, the state determination section 70 determines that the hydraulic excavator 100 is travelling straight ahead. When the difference between the first tilting command value and the second tilting command value is larger than the volume difference threshold value, the state determination section 70 determines that the hydraulic excavator 100 is not travelling straight ahead.

[0056] The first tilting command value and the second tilting command value are calculated on the basis of the travelling operation signal from the travelling operation sensor 5, the work operation signal from the work operation sensor 3, and the swing operation signal from the swing operation sensor 4. For example, the first hydraulic pump 11 and the second hydraulic pump 21 are controlled so as to increase in volume as the operation amounts of the left and right travelling levers 6a and 7a and the left and right operation levers 8a and 9a increase. Such control is called positive control. It should be noted that the method of controlling the hydraulic pumps 11 and 21 is not limited to this.

[0057] The state determination section 70 determines whether or not the hydraulic excavator 100 is during the travelling single operation and is travelling straight ahead. Where the state determination section 70 determines that the hydraulic excavator 100 is during the travelling single operation and is travelling straight ahead, it is assumed that diagnostic conditions are satisfied and a valid mode is set to validate a parameter used for abnormality diagnosis. Where the state determination section 70 determines that the hydraulic excavator 100 is during neither the travelling single operation nor the travelling in straight ahead, it is assumed that the diagnostic conditions are not satisfied and an invalid mode is set to invalidate the parameter used for abnormality diagnosis. It should be noted that in the present embodiment, the method of calculating a corrected differential pressure value ΔPc that is a parameter (abnormality determination evaluation value) used for abnormality diagnosis will be described later.

[0058] The differential pressure value calculation section 81 calculates a differential pressure value ΔP obtained by subtracting the second pump pressure (pressure value) P2 sensed by the second pressure sensor 23 from the first pump pressure (pressure value) P1 sensed by the first pressure sensor 13 (ΔP = P1 - P2). In this manner, the differential pressure value calculation section 81 calculates the differential pressure value ΔP as travelling feature amounts of the travel devices 50 and 60 on the basis of the sensor values representing the travelling state sensed by the first pressure sensor 13 and the second pressure sensor 23. The differential pressure value calculation section 81 corrects the differential pressure value ΔP by a correction amount Pc calculated by the correction amount calculation section 83 and calculates the corrected differential pressure value ΔPc that is the differential pressure value after correction. That is, the differential pressure value calculation section 81 calculates the corrected differential pressure value ΔPc as a corrected travelling feature amount by correcting the travelling feature amount (differential pressure value ΔP) on the basis of the correction amount Pc.

[0059] The correction amount calculation section 83 calculates the roll angle φ as an inclination feature amount on the basis of the sensor value representing the inclination angle (inclination state) sensed by the inclination angle sensor 76. In addition, the correction amount calculation section 83 calculates the correction amount Pc on the basis of correction amount parameters (a loss torque coefficient C and a load characteristic table T to be described later) stored in advance in the non-volatile memory 2b and the roll angle φ. The method of calculating the correction amount Pc by the correction amount calculation section 83 will be described later.

[0060] Where the valid mode is set by the state determination section 70 (where the hydraulic excavator 100 is during the travelling single operation and is travelling straight ahead), the effective differential pressure value extraction section 82 extracts the corrected differential pressure value ΔPc from the differential pressure value calculation section 81 as the abnormality determination evaluation value, and outputs it to the abnormality determination section 90. Where the invalid mode is set by the state determination section 70 (where the hydraulic excavator 100 is not during the travelling single operation or where the hydraulic excavator 100 is not travelling straight ahead), the effective differential pressure value extraction section 82 sets the abnormality determination evaluation value as 0 (zero) and outputs it to the abnormality determination section 90.

[0061] The abnormality determination section 90 determines whether or not there is an abnormality in either one of the left travel device 50 and the right travel device 60 on the basis of the comparison result between the abnormality determination evaluation value (the corrected differential pressure value ΔPc in the valid mode) from the effective differential pressure value extraction section 82 and a determination reference value ΔP0. Here, the determination reference value ΔP0 is a value that is empirically obtained and is stored in advance in the non-volatile memory 2b. It should be noted that it is preferable that the controller 2 is configured to be capable of changing the determination reference value ΔP0 on the basis of an operation performed by the operator or the like on the input device.

[0062] The abnormality determination section 90 outputs the determination result to the display device 91 and the communication device 92. The display device 91 displays an image representing the determination result of the abnormality determination section 90 on the screen. The communication device 92 transmits the determination result of the abnormality determination section 90 to the server 40. The display device, a printing device, and the like are connected to the server 40. The server 40 outputs the received determination result to the display device or the printing device connected to the server 40. Accordingly, the operator, the vehicle manager, and the service person can quickly grasp an abnormality of the travel devices 50 and 60 of the hydraulic excavator 100.

[0063] Next, a method of calculating the correction amounts Pc1 and Pc2 of the differential pressure value ΔP in consideration of the inclination state of the travelling road surface 109 will be described. First, the relationship between the pump pressure and the travel driving force will be described. In order to establish the conditions of the abnormality diagnosis of the travel devices 50 and 60, it is necessary that the hydraulic excavator 100 is travelling straight ahead. During travelling straight ahead, a pump pressure acts on the travelling motors 31 and 32 as a driving pressure. Thus, the travel driving force by the pump pressure is generated in the travelling motors 31 and 32.

[0064] A left travel driving force TmotL that is the travel driving force by the left travelling motor 31 and a right travel driving force TmotR that is the travel driving force by the right travelling motor 32 are represented by the following equations (4) and (5), respectively. TmotL = P 1 × q 1 / 2 Π × Ratio TmotR = P 2 × q 2 / 2 Π × Ratio

[0065] Here, P1 is the delivery pressure (first pump pressure) of the first hydraulic pump 11, and P2 is the delivery pressure (second pump pressure) of the second hydraulic pump 21. In the equations, q1 is the displacement volume of the left travelling motor 31, and q2 is the displacement volume of the right travelling motor 32. Ratio is a reduction ratio between the travelling reduction gears 54 and 64 of the travelling motors 31 and 32. During travelling straight ahead, the displacement volume q1 of the left travelling motor 31 is equal to the displacement volume q2 of the right travelling motor 32. Therefore, the displacement volume q1 of the left travelling motor 31 and the displacement volume q2 of the right travelling motor 32 are also hereinafter referred to as a motor volume q (q = q1 = q2).

[0066] The driving force of the left travelling reduction gear 54 is represented by the following equation (6), and the driving force of the right travelling reduction gear 64 is represented by the following equation (7). TmotL = P 1 × q / 2 Π × Ratio = TtrvL + TlossL TmotR = P 2 × q / 2 Π × Ratio = TtrvR + TlossR

[0067] Here, TtrvL is a torque (left travel driving effective torque) effectively used for travel driving in the left travelling motor 31, and TtrvR is a torque (right travel driving effective torque) effectively used for travel driving in the right travelling motor 32. TlossL is a loss torque such as a drag resistance force at the time of the travelling operation in the left travelling motor 31, and is hereinafter referred to as a left loss torque. TlossR is a loss torque such as a drag resistance force at the time of the travelling operation in the right travelling motor 32, and is hereinafter referred to as a right loss torque.

[0068] When the hydraulic excavator 100 is travelling straight ahead in the horizontal posture, the left loss torque and the right loss torque are substantially equal to each other (TlossL ≈ TlossR). Therefore, an effective torque difference ΔT that is the difference between the left travel driving force and the right travel driving force is represented by the following equation (8) according to the equations (6) and (7). ΔT = TtrvL − TtrvR = q / 2 Π × Ratio × P 1 − P 2

[0069] According to the equation (8), it is understood that the effective torque difference ΔT at the time of the travel driving can be grasped from the differential pressure value ΔP (= P1 - P2) between the first pump pressure P1 and the second pump pressure P2.

[0070] However, when the hydraulic excavator 100 is travelling straight ahead in the inclined posture, a case where the loss torques TlossL and TlossR acting on the travel devices 50 and 60 are largely different from each other is also assumed. Therefore, where the equation (7) is subtracted from the equation (6) when the hydraulic excavator 100 is travelling straight ahead in the inclined posture, the left loss torque TlossL and the right loss torque TlossR remain without being canceled as represented by the following equation (9).

[0071] Therefore, in order to perform abnormality diagnosis by the differential pressure value ΔP, it is necessary to perform correction in consideration of the loss torques TlossL and TlossR.

[0072] Next, a method of correction will be described in detail. As described above, in a state where the machine body 107 is inclined to the left and right, the loads acting on the left and right travel devices 50 and 60 are different from each other as depicted in Fig. 8. Where the loss torque at the time of the travel driving is assumed to be a force (loss torque) according to a load such as a friction force, an estimated value of the left loss torque (hereinafter, a left loss torque estimated value) TlossL_est and an estimated value of the right loss torque (hereinafter, a right loss torque estimated value) TlossR_est are represented by the following equations (10) and (11), respectively. TlossL_est = C 1 × FL TlossR_est = C 2 × FR

[0073] Here, FL is the load applied to the left travel device 50 and FR is the load applied to the right travel device 60. C1 is the loss torque coefficient (corresponding to a friction coefficient) of the left travel device 50, and C2 is the loss torque coefficient (corresponding to a friction coefficient) of the right travel device 60. The loss torque coefficients C1 and C2 may be basically considered to be substantially equivalent to each other because the left and right travel devices 50 and 60 have equivalent configurations. Therefore, the loss torque coefficients C1 and C2 are also hereinafter referred to as a loss torque coefficient C (C = C1 = C2). The loss torque coefficients C1 and C2 are set from design values, past measurement data, knowledge, and the like, and are stored in advance in the non-volatile memory 2b.

[0074] The controller 2 corrects the differential pressure value ΔP so as to suppress (cancel) the influence (the difference between the left loss torque TlossL and the right loss torque TlossR)) of the inclination state by correcting the amount of change in the differential pressure value ΔP due to inclination.

[0075] Specifically, as depicted in an equation (12), the influence of the inclination state can be canceled by subtracting (TlossL - TlossR) on the right side of the equation (9) by (TlossL_est - TlossR_est). q / 2 π + Ratio × P 1 − P 2 = TtrvL + TlossL − TlossL _ est − TtrvR + TlossR − TlossR _ est

[0076] Here, if the loss torque estimated values TlossL_est and TlossR_est have less error with respect to the loss torques TlossL and TlossR, the following equation (13) is obtained. q / 2 π × Ratio × P 1 − P 2 = TtrvL − TtrvR

[0077] When the equation (13) is arranged in units of pressure, an equation (14) is obtained. P 1 − P 2 = 2 π / q × Ratio × TtrvL − TtrvR

[0078] According to this, even where the travelling loss torques change due to the difference between the loads acting on the travel devices 50 and 60 in the inclined posture, the effective driving force difference excluding the influence of the inclination state can be grasped by sensing the inclination state, estimating the loss torques from the acting loads, and correcting the differential pressure value on the basis of the estimation result.

[0079] Fig. 11 is a diagram for explaining details of correction logic by the differential pressure value calculation section 81 and the correction amount calculation section 83.

[0080] As depicted in Fig. 11, the correction amount calculation section 83 refers to the load characteristic table T and computes the load FL acting on the left travel device 50 and the load FR acting on the right travel device 60 on the basis of the roll angle φ of the lower track structure 101 sensed by the inclination angle sensor 76. The load characteristic table T is a data table for defining the relationship between the roll angle φ and the loads FL and FR described by using Fig. 8. The load characteristic table T is stored in advance in the non-volatile memory 2b.

[0081] The correction amount calculation section 83 multiplies the computed load FL acting on the left travel device 50 by the loss torque coefficient C to calculate the left loss torque estimated value TlossL_est. The correction amount calculation section 83 multiplies the computed load FR acting on the right travel device 60 by the loss torque coefficient C to calculate the right loss torque estimated value TlossR_est.

[0082] The correction amount calculation section 83 computes a first correction amount Pc1 by converting the calculated left loss torque estimated value TlossL_est into a unit of pressure by using the motor volume q and the reduction ratio Ratio. In addition, the correction amount calculation section 83 computes a second correction amount Pc2 by converting the calculated right loss torque estimated value TlossR_est into a unit of pressure by using the motor volume q and the reduction ratio Ratio. The first correction amount Pc1 and the second correction amount Pc2 that are correction amounts of pressure are represented by the following equations (15) and (16). Pc 1 = 2 Π / q × Ratio × TlossL _ est Pc 2 = 2 Π / q × Ratio × TlossR _ est

[0083] The correction amount calculation section 83 outputs the first correction amount Pc1 and the second correction amount Pc2 calculated by the equations (15) and (16) to the differential pressure value calculation section 81.

[0084] The first correction amount Pc1 corresponds to a change in the first pump pressure P1 in the inclined posture relative to the first pump pressure P1 in the horizontal posture (difference between the first pump pressure P1 in the horizontal posture and the first pump pressure P1 in the inclined posture). The first correction amount Pc1 becomes larger as the height of the left travel device 50 becomes lower and the height of the right travel device 60 becomes higher in the inclined posture. In addition, the first correction amount Pc1 becomes smaller as the height of the left travel device 50 becomes higher and the height of the right travel device 60 becomes lower in the inclined posture. The second correction amount Pc2 corresponds to a change in the second pump pressure P2 in the inclined posture relative to the second pump pressure P2 in the horizontal posture (difference between the second pump pressure P2 in the horizontal posture and the second pump pressure P2 in the inclined posture). The second correction amount Pc2 becomes smaller as the height of the left travel device 50 becomes lower and the height of the right travel device 60 becomes higher in the inclined posture. In addition, the second correction amount Pc2 becomes larger as the height of the left travel device 50 becomes higher and the height of the right travel device 60 becomes lower in the inclined posture.

[0085] The differential pressure value calculation section 81 computes the differential pressure value ΔP by subtracting the second pump pressure P2 sensed by the second pressure sensor 23 from the first pump pressure P1 sensed by the first pressure sensor 13. The differential pressure value calculation section 81 corrects the differential pressure value ΔP by using the first correction amount Pc1 and the second correction amount Pc2. Specifically, the differential pressure value calculation section 81 computes the corrected differential pressure value ΔPc that is the differential pressure value after correction, by subtracting the first correction amount Pc1 and adding the second correction amount Pc2 from / to the differential pressure value ΔP. The corrected differential pressure value ΔPc is output to the effective differential pressure value extraction section 82. It should be noted that when the hydraulic excavator 100 is travelling straight ahead in the horizontal posture, the load FL and the load FR become equal to each other. That is, the first correction amount Pc1 and the second correction amount Pc2 become equal to each other. Therefore, the correction amount Pc (= second correction amount Pc2 - first correction amount Pc1) added to the differential pressure value ΔP becomes 0 (zero), and the differential pressure value ΔP (= ΔPc) in a case where the correction is not substantially performed is output to the effective differential pressure value extraction section 82.

[0086] As described above, the controller 2 according to the present embodiment computes the correction amount Pc (= Pc2 - Pc1) for canceling the influence of the inclination state of the lower track structure 101 on the first pump pressure P1 and the second pump pressure P2 on the basis of the inclination angle (roll angle φ) of the lower track structure 101 sensed by the inclination angle sensor 76. The correction amount Pc corresponds to a variation in the differential pressure value ΔP (difference between the differential pressure value in the horizontal posture and the differential pressure value in the inclined posture) due to an increase in the load acting on one of the left travel device 50 and the right travel device 60 and a decrease in the load acting on the other of the left travel device 50 and the right travel device 60 when the lower track structure 101 is inclined in the lateral direction. The controller 2 calculates the corrected differential pressure value ΔPc by canceling the variation in the differential pressure value with the horizontal posture as a difference, which is included in the differential pressure value ΔP computed in the inclined posture, by the correction amount Pc.

[0087] Fig. 12 is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller 2. The flowchart depicted in Fig. 12 is started by, for example, turning on the ignition switch and is repeatedly executed at a predetermined control cycle.

[0088] In Step S2, the differential pressure value calculation section 81 calculates the differential pressure value ΔP obtained by subtracting the second pump pressure P2 from the first pump pressure P1.

[0089] In the next Step S4, the correction amount calculation section 83 refers to the load characteristic table T and computes the load FL of the left travel device 50 and the load FR of the right travel device 60 on the basis of the roll angle φ of the lower track structure 101 sensed by the inclination angle sensor 76. The correction amount calculation section 83 calculates the first correction amount Pc1 and the second correction amount Pc2 on the basis of the loads FL and FR.

[0090] In the next Step S6, the differential pressure value calculation section 81 calculates the corrected differential pressure value ΔPc by adding the correction amount Pc (second correction amount Pc2 - first correction amount Pc1) calculated in Step S4 to the differential pressure value ΔP calculated in Step S2.

[0091] In the next Step S10, the state determination section 70 determines whether there is no work operation on the basis of the work operation signal from the work operation sensor 3. When it is determined in Step S10 that there is no work operation (Yes), the processing proceeds to Step S20, and when it is determined in Step S10 that there is a work operation (No), the invalid mode is set, and the processing depicted in Fig. 12 in the present control cycle is terminated. That is, the processing proceeds to Step S2 of the next control cycle.

[0092] In Step S20, the state determination section 70 determines whether there is no swing operation on the basis of the swing operation signal from the swing operation sensor 4. When it is determined in Step S20 that there is no swing operation (Yes), the processing proceeds to Step S30, and when it is determined in Step S20 that there is a swing operation (No), the invalid mode is set, and the processing depicted in Fig. 12 in the present control cycle is terminated.

[0093] In Step S30, the state determination section 70 determines whether or not there is a travelling operation on the basis of the travelling operation signal from the travelling operation sensor 5. When it is determined in Step S30 that there is a travelling operation (Yes), the processing proceeds to Step S40, and when it is determined in Step S30 that there is no travelling operation (No), the invalid mode is set, and the processing depicted in Fig. 12 in the present control cycle is terminated.

[0094] In Step S40, it is determined whether or not the hydraulic excavator 100 is travelling straight ahead on the basis of the first tilting command value and the second tilting command value. The state determination section 70 calculates the first tilting command value and the second tilting command value on the basis of the work operation signal, the swing operation signal, and the travelling operation signal. It should be noted that the state determination section 70 may acquire the first tilting command value and the second tilting command value calculated by a hydraulic pump control section (not illustrated).

[0095] Where the first tilting command value and the second tilting command value are equal to each other during the travelling single operation, the flow rates supplied from the first hydraulic pump 11 and the second hydraulic pump 21 to the left and right travelling motors 31 and 32 become equal to each other. At this time, the rotational speeds of the left and right travelling motors 31 and 32 become equal to each other, and the left and right travel devices 50 and 60 travel straight ahead. Thus, it is possible to determine whether or not the left and right travel devices 50 and 60 are travelling straight ahead on the basis of whether or not the first tilting command value and the second tilting command value are equal to each other. Specifically, in consideration of manufacturing errors of the first hydraulic pump 11, the second hydraulic pump 21, the left and right travelling motors 31 and 32, and the like, it is determined that the left and right travel devices 50 and 60 are travelling straight ahead when the difference between the first tilting command value and the second tilting command value is equal to or smaller than a predetermined threshold value.

[0096] When it is determined in Step S40 that the left and right travel devices 50 and 60 are travelling straight ahead (Yes), the valid mode is set, and the processing proceeds to Step S50, and when it is determined in Step S40 that the left and right travel devices 50 and 60 are not travelling straight ahead (No), the invalid mode is set, and the processing depicted in Fig. 12 in the present control period is terminated.

[0097] In Step S50, the effective differential pressure value extraction section 82 extracts the corrected differential pressure value ΔPc calculated in Step S6 of the present control cycle as the abnormality determination evaluation value used for abnormality determination. The abnormality determination evaluation value is a feature amount for evaluating abnormality sign states of the travel devices 50 and 60.

[0098] In the next Step S60, the abnormality determination section 90 determines whether or not the corrected differential pressure value ΔPc extracted as the abnormality determination evaluation value is equal to or smaller than a predetermined upper limit value Pu. The determination reference value (positive value) ΔP0 is employed for the predetermined upper limit value Pu. The determination reference value ΔP0 is set in advance in consideration of pressure sensing errors and manufacturing errors, and is stored in the non-volatile memory 2b. The manufacturing errors include, for example, manufacturing errors of the first hydraulic pump 11, the second hydraulic pump 21, and the left and right travel devices 50 and 60. The predetermined upper limit value Pu is a threshold value for determining whether or not there is an abnormality in the left travel device 50.

[0099] For example, where the loss torques of the left and right travel devices 50 and 60 are the same during travelling straight ahead on the horizontal road surface 109a, the left and right travelling motors 31 and 32 are equally driven by the first hydraulic pump 11 and the second hydraulic pump 21. Therefore, the first pump pressure P1 and the second pump pressure P2 become the same, and the corrected differential pressure value ΔPc becomes equal to or smaller than the predetermined upper limit value Pu (ΔPc ≤ Pu). It should be noted that when travelling on the horizontal road surface 109a, the corrected differential pressure value ΔPc corresponds to the differential pressure value ΔP. On the other hand, where the loss torque of the left travel device 50 is larger than the loss torque of the right travel device 60 during travelling straight ahead on the horizontal road surface 109a, the first pump pressure P1 becomes larger than the second pump pressure P2, and the corrected differential pressure value ΔPc (> 0) becomes larger than the predetermined upper limit value Pu (> 0) (ΔPc > Pu).

[0100] Where the hydraulic excavator 100 travels on the inclined road surface 109b, the influence of the pressure difference between the first pump pressure P1 and the second pump pressure P2 caused by the inclined posture is canceled by correction. Therefore, even where the hydraulic excavator 100 is travelling on the inclined road surface 109b, it can be determined, as similar to when travelling on the horizontal road surface 109a, that the pressure difference between the first pump pressure P1 and the second pump pressure P2 becomes larger due to the abnormality of the travel device 50 or 60 by comparing the corrected differential pressure value ΔPc with the upper limit value Pu.

[0101] When it is determined in Step S60 that the corrected differential pressure value ΔPc is larger than the predetermined upper limit value Pu (No), the processing proceeds to Step S70, and when it is determined in Step S60 that the corrected differential pressure value ΔPc is equal to or smaller than the predetermined upper limit value Pu (Yes), the processing proceeds to Step S80.

[0102] In Step S70, the abnormality determination section 90 determines that there is an abnormality in the left travel device 50, and advances the processing to Step S110.

[0103] In Step S80, the abnormality determination section 90 determines whether or not the corrected differential pressure value ΔPc extracted as the abnormality determination evaluation value is equal to or larger than a predetermined lower limit value Pl. For the predetermined lower limit value Pl, a value (-ΔP0) obtained by multiplying the determination reference value ΔP0 by -1 is employed. The predetermined lower limit value Pl is a threshold value for determining whether or not there is an abnormality in the right travel device 60. It should be noted that the present invention is not limited to the case where the absolute value of the lower limit value Pl and the absolute value of the upper limit value Pu are made equal to each other. The absolute value of the lower limit value Pl and the absolute value of the upper limit value Pu may be different from each other.

[0104] For example, where the loss torques of the left and right travel devices 50 and 60 are the same during travelling straight ahead on the horizontal road surface 109a, the left and right travelling motors 31 and 32 are equally driven by the first hydraulic pump 11 and the second hydraulic pump 21. Therefore, the first pump pressure P1 and the second pump pressure P2 become the same, and the corrected differential pressure value ΔPc becomes equal to or larger than the predetermined lower limit value Pl (ΔPc ≥ Pl). It should be noted that when travelling on the horizontal road surface 109a, the corrected differential pressure value ΔPc corresponds to the differential pressure value ΔP. On the other hand, where the loss torque of the right travel device 60 is larger than the loss torque of the left travel device 50 during travelling straight ahead on the horizontal road surface 109a, the second pump pressure P2 becomes larger than the first pump pressure P1, and the corrected differential pressure value ΔPc (< 0) becomes smaller than the predetermined lower limit value Pl (< 0) (ΔPc < Pl).

[0105] Where the hydraulic excavator 100 travels on the inclined road surface 109b, the influence of the pressure difference between the first pump pressure P1 and the second pump pressure P2 caused by the inclined posture is canceled by correction. Therefore, even where the hydraulic excavator 100 is travelling on the inclined road surface 109b, it can be determined, as similar to when travelling on the horizontal road surface 109a, that the pressure difference between the first pump pressure P1 and the second pump pressure P2 becomes larger due to the abnormality of the travel device 50 or 60, by comparing the corrected differential pressure value ΔPc with the lower limit value Pl.

[0106] When it is determined in Step S80 that the corrected differential pressure value ΔPc is smaller than the predetermined lower limit value Pl (No), the processing proceeds to Step S90, and when it is determined in Step S80 that the corrected differential pressure value ΔPc is equal to or larger than the predetermined lower limit value Pl (Yes), the processing proceeds to Step S100.

[0107] In Step S90, the abnormality determination section 90 determines that there is an abnormality in the right travel device 60, and advances the processing to Step S110.

[0108] In Step S100, the abnormality determination section 90 determines that there is no abnormality (that is, normal) in the left and right travel devices 50 and 60, and advances the processing to Step S110.

[0109] In Step S110, the abnormality determination section 90 outputs the determination results in Step S70, S90, or S100 to the display device 91 and the communication device 92. The display device 91 displays an image (an icon or the like) representing the determination results on the display screen. That is, the controller 2 notifies the operator of the determination results via the display device 91. The communication device 92 transmits the determination results to the server 40. The server 40 outputs the received determination results to a display device in the management facility. The display device in the management facility displays an image (an icon or the like) representing the determination results on the display screen. That is, the controller 2 notifies the vehicle manager and the service person in the management facility of the determination results via the communication by the communication device 92. When the output processing of the determination results (Step S110) is completed, the processing depicted in Fig. 12 in the present control cycle is terminated.

[0110] As described above, in the present embodiment, the controller 2 computes the correction amount Pc of the differential pressure value ΔP on the basis of the roll angle (inclination angle) φ of the lower track structure 101, and computes the corrected differential pressure value ΔPc as the abnormality determination evaluation value used for abnormality determination by using the correction amount Pc. The corrected differential pressure value ΔPc corresponds to the differential pressure value obtained by canceling the variation due to the influence of the inclination. Therefore, even where the driving force difference is generated by the inclination, the influence of the inclination state is canceled. As a result, the differential pressure value ΔP equal to that when travelling straight ahead on the horizontal plane is calculated as the corrected differential pressure value ΔPc. Accordingly, the accuracy of the state monitoring of the travel system is improved regardless of the inclination situation.

[0111] According to the first embodiment described above, the following action and effect are exhibited. (1) The diagnostic device 80 is provided with the processor (first processor) 2a that diagnoses an abnormality of the travel devices 50 and 60 on the basis of the travelling feature amount (differential pressure value ΔP) representing the travelling states of the travel devices 50 and 60 mounted to the machine body 107 of the hydraulic excavator (work machine) 100, and the output device (the display device 91 and the communication device 92) that outputs the result of the diagnosis performed by the processor 2a. The processor 2a acquires the inclination feature amount (roll angle φ) representing the inclination state of the machine body 107. The processor 2a computes the correction amount Pc for canceling the influence of the inclination state of the machine body 107 on the travelling feature amounts (differential pressure value ΔP) of the travel devices 50 and 60 on the basis of the inclination feature amount (roll angle φ). The processor 2a computes the corrected travelling feature amount (corrected differential pressure value ΔPc) by correcting the travelling feature amount (differential pressure value ΔP) on the basis of the correction amount Pc. The processor 2a computes the abnormality determination evaluation value (corrected differential pressure value ΔPc in the valid mode) on the basis of the corrected travelling feature amount (corrected differential pressure value ΔPc). The processor 2a determines whether or not there is an abnormality in the travel device 50 or 60 on the basis of the abnormality determination evaluation value, and outputs, when it is determined that there is an abnormality, the determination result to the output device.

[0112] For example, the display device 91 as the output device outputs a notification image for informing the operator that an abnormality has occurred. In addition, the communication device 92 as the output device outputs to the server 40 notification information for informing the vehicle manager and the service person that an abnormality has occurred.

[0113] According to this configuration, it is possible to provide the diagnostic device 80 that prevents erroneous detection of an abnormality of the travel devices 50 and 60 when travelling on the inclined road surface, and is capable of appropriately detecting an abnormality of the travel devices 50 and 60.

[0114] (2) In the first embodiment, the hydraulic excavator 100 is provided with the diagnostic device 80. The hydraulic excavator 100 is provided with the machine body 107, the work device 103 that is attached to the machine body 107, the first hydraulic pump 11 and the second hydraulic pump 21 that are provided in the machine body 107, the left travel device 50 that has the left travelling motor 31 driven by hydraulic fluid supplied from the first hydraulic pump 11, the right travel device 60 that has the right travelling motor 32 driven by hydraulic fluid supplied from the second hydraulic pump 21, the travelling lever devices (travelling operation devices) 6 and 7 that issue instructions of operations of the left travel device 50 and the right travel device 60, the processor (first processor) 2a that controls the volumes (displacement volumes) of the first hydraulic pump 11 and the second hydraulic pump 21 in accordance with the operations of the travelling lever devices 6 and 7, the first pressure sensor 13 that senses the first pump pressure P1 that is the delivery pressure of the first hydraulic pump 11, the second pressure sensor 23 that senses the second pump pressure P2 that is the delivery pressure of the second hydraulic pump 21, and the inclination angle sensor (inclination state sensor) 76 that senses the inclination angle (inclination state) of the machine body 107 with respect to a horizontal plane. The machine body 107 has the lower track structure 101 provided with the left travel device 50 and the right travel device 60, and the upper swing structure 102 swingably provided with respect to the lower track structure 101.

[0115] The processor 2a computes the differential pressure value ΔP between the first pump pressure P1 and the second pump pressure P2 as the travelling feature amount. The processor 2a computes the roll angle φ that is the inclination angle of the machine body 107 in the lateral direction as the inclination feature amount on the basis of a sensor value representing the inclination angle (inclination state) sensed by the inclination angle sensor 76. The processor 2a computes the correction amount Pc (second correction amount Pc2 - first correction amount Pc1) for canceling the influence of the inclination state of the lower track structure 101 configuring the machine body 107 on the first pump pressure P1 and the second pump pressure P2 on the basis of the roll angle (inclination angle) φ of the lower track structure 101.

[0116] The processor 2a computes, as the correction amount Pc, a variation in the differential pressure value ΔP caused by an increase in the load acting on one of the left travel device 50 and the right travel device 60 and a decrease in the load acting on the other of the left travel device 50 and the right travel device 60 due to the inclination of the lower track structure 101 in the lateral direction.

[0117] The processor 2a computes the corrected differential pressure value ΔPc as a corrected travelling feature amount by correcting the computed differential pressure value ΔP on the basis of the correction amount Pc. The processor 2a computes the abnormality determination evaluation value on the basis of the computed corrected differential pressure value ΔPc. It should be noted that in the present embodiment, the corrected differential pressure value ΔPc is employed for the abnormality determination evaluation value. The processor 2a determines whether or not there is an abnormality in either one of the left travel device 50 and the right travel device 60 on the basis of the computed corrected differential pressure value ΔPc as the abnormality determination evaluation value. When it is determined that there is an abnormality, the processor 2a outputs the determination result to the output device (the display device 91 and the communication device 92). According to this configuration, it is possible to prevent erroneous detection of an abnormality of the travel devices 50 and 60 when the hydraulic excavator 100 provided with the hydraulically-driven travel devices 50 and 60 is travelling on the inclined road surface. According to the present embodiment, it is possible to appropriately diagnose the presence or absence of an abnormality of the travel devices 50 and 60 even when the hydraulic excavator 100 is travelling in a state of being inclined to the left and right.

[0118] (3) When it is determined that the left travel device 50 and the right travel device 60 are travelling straight ahead, the processor 2a makes the determination of an abnormality. When the lower track structure 101 is travelling while being swung to the left and right by making a difference between the speeds of the left and right travel devices 50 and 60, there is a risk that the abnormality of the travel devices 50 and 60 cannot be accurately detected depending on the difference between the left and right speeds. Accordingly, in the present embodiment, an abnormality is determined when the left travel device 50 and the right travel device 60 are travelling straight ahead. Therefore, it is possible to accurately detect an abnormality of the left and right travel devices 50 and 60.

[0119] (4) When it is determined that the work device 103 and the upper swing structure 102 are not operated, the processor 2a makes the determination of an abnormality. When at least one of the work device 103 and the upper swing structure 102 is operated, the load balance between the left and right of the machine body 107 changes due to the operation, and there is a risk that the abnormality of the travel devices 50 and 60 cannot be accurately detected. Accordingly, in the present embodiment, an abnormality is determined when the work device 103 and the upper swing structure 102 are not operated. Therefore, it is possible to accurately detect an abnormality of the left and right travel devices 50 and 60.<Modified example of first embodiment>

[0120] In the first embodiment, an example in which the travelling feature amount is the differential pressure value ΔP has been described, but the travelling feature amount is not limited thereto. For example, the travelling feature amount may be a driving force difference that is a difference between the travel driving force of the left travel device 50 and the travel driving force of the right travel device 60. According to this configuration, the present invention can be applied to a travel device of an electrically driven motor driving type. The travel driving force of the electrically driven travel device may be computed on the basis of a torque sensed by a torque sensor, or may be estimated on the basis of a current and a voltage sensed by a current sensor and a voltage sensor, respectively.

[0121] In addition, in the first embodiment, an example in which the inclination feature amount is the roll angle φ has been described, but the inclination feature amount is not limited thereto. For example, the inclination feature amount may be a distance difference that is a difference between a distance of the left travel device 50 from the reference plane in the vertical direction and a distance of the right travel device 60 from the reference plane in the vertical direction. Since the width of the travel device (the distance between the left travel device 50 and the right travel device 60) is known, the distance difference can be said to be a parameter representing the inclination state. It should be noted that in the following embodiment, an example in which the travelling feature amount is the differential pressure value ΔP and the inclination feature amount is the roll angle φ as similar to the first embodiment will be described. However, the travelling feature amount may be a parameter representing the travelling state, and the inclination feature amount may be a parameter representing the inclination state, as similar to the modified example.<Second Embodiment>

[0122] A hydraulic excavator 100 according to a second embodiment of the present invention will be described with reference to Fig. 13 to Fig. 15. It should be noted that the same reference symbols are given to the configurations same as or corresponding to those described in the first embodiment, and differences will be mainly described.

[0123] Fig. 13 is a diagram similar to that of Fig. 10 and is a functional block diagram of a controller 202 according to the second embodiment. The controller 202 has an inclination state determination section 277 instead of the correction amount calculation section 83 of the controller 2 according to the first embodiment. In addition, the controller 202 has a differential pressure value calculation section 281, an effective differential pressure value extraction section 282, and an abnormality determination section 290 instead of the differential pressure value calculation section 81, the effective differential pressure value extraction section 82, and the abnormality determination section 90 of the controller 2 according to the first embodiment. The processor 2a of the controller 202 realizes these functions by executing the programs stored in the non-volatile memory 2b.

[0124] In the second embodiment, the correction of the differential pressure value described in the first embodiment is not performed. Therefore, where the difference (hereinafter, also referred to as a load difference due to inclination) ΔF of the loads FL and FR on the inclined road surface 109b from the loads FL and FR on the horizontal road surface 109a becomes larger than a predetermined value (hereinafter, also referred to as an allowable load difference) ΔFt, there is a risk that the abnormality detection on the basis of the differential pressure value ΔP cannot be accurately performed. Thus, the controller 2 according to the second embodiment is configured not to execute the abnormality determination based on the differential pressure value ΔP in a case where the load difference ΔF due to inclination becomes larger than the allowable load difference ΔFt.

[0125] Fig. 14 is a diagram for depicting an allowable load difference and an allowable roll angle range.

[0126] As depicted in Fig. 14, in the present embodiment, the magnitude of the roll angle φ (the absolute value of the roll angle φ) of the lower track structure 101 when the ratio of the smaller load between the loads FL and FR is 90% to the loads FL and FR on the horizontal road surface 109a is defined as an allowable roll angle φt. In addition, a range of a lower limit angle (-φt) or larger and an upper limit angle (+φt) or smaller is defined as an allowable roll angle range. The upper limit angle (+φt) corresponds to the allowable roll angle φt (positive value). The lower limit angle (-φt) corresponds to a value obtained by multiplying the allowable roll angle φt by -1. Where the roll angle φ is within the allowable roll angle range depicted in Fig. 14, the accuracy of the abnormality determination can be secured.

[0127] Fig. 15 is a diagram similar to that of Fig. 12 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller 202 according to the second embodiment. In the flowchart of Fig. 15, the processing of Steps S4 and S6 of the flowchart of Fig. 12 is omitted. That is, the differential pressure value calculation section 281 depicted in Fig. 13 outputs the computed differential pressure value ΔP to the effective differential pressure value extraction section 82 without correction. In addition, in the flowchart of Fig. 15, processing of Steps S250, S260, and S280 is executed instead of the processing of Steps S50, S60, and S80 of the flowchart of Fig. 12. Further, in the second embodiment, when positive determination is made in Step S40, inclination state determination processing (Step S245) is executed.

[0128] As depicted in Fig. 15, when positive determination is made in Step S40, the processing proceeds to Step S245. In Step S245, the inclination state determination section 277 determines whether or not the roll angle φ sensed by the inclination angle sensor 76 is within the allowable roll angle range. Where the roll angle φ is equal to or larger than the lower limit angle (-φt) and equal to or smaller than the upper limit angle (+φt), it is determined that the roll angle φ is within the allowable roll angle range. When it is determined that the roll angle φ is within the allowable roll angle range (Yes), the valid mode is set, and the processing proceeds to Step S250. Where the roll angle φ is smaller than the lower limit angle (-φt) or the roll angle φ is larger than the upper limit angle (+φt), it is determined that the roll angle φ is not within the allowable roll angle range. When it is determined that the roll angle φ is not within the allowable roll angle range (No), the invalid mode is set, and the processing depicted in Fig. 15 in the present control cycle is terminated.

[0129] In Step S250, the effective differential pressure value extraction section 282 extracts the differential pressure value ΔP calculated in Step S2 of the present control cycle as the abnormality determination evaluation value used for abnormality determination.

[0130] In the next Step S260, the abnormality determination section 290 determines whether or not the differential pressure value ΔP extracted as the abnormality determination evaluation value is equal to or smaller than the predetermined upper limit value Pu. When it is determined in Step S260 that the differential pressure value ΔP is larger than the predetermined upper limit value Pu (No), the processing proceeds to Step S70, and when it is determined in Step S260 that the differential pressure value ΔP is equal to or smaller than the predetermined upper limit value Pu (Yes), the processing proceeds to Step S280.

[0131] In Step S280, the abnormality determination section 290 determines whether or not the differential pressure value ΔP extracted as the abnormality determination evaluation value is equal to or larger than the predetermined lower limit value Pl. When it is determined in Step S280 that the differential pressure value ΔP is smaller than the predetermined lower limit value Pl (No), the processing proceeds to Step S90, and when it is determined in Step S280 that the differential pressure value ΔP is equal to or larger than the predetermined lower limit value Pl (Yes), the processing proceeds to Step S100.

[0132] As described above, in the second embodiment, when the absolute value of the roll angle φ (the magnitude of the roll angle φ) of the lower track structure 101 is larger than the predetermined angle φt, the abnormality determination processing is not executed because the abnormality determination processing is affected. The predetermined angle φt is a threshold value of the roll angle φ for determining whether or not the inclination state affects the abnormality determination processing of the travel devices 50 and 60. The predetermined angle φt corresponds to the roll angle φ of, for example, ±10% (in the present embodiment, -10%) with respect to the balanced load when there is no inclination (φ = 0°). Therefore, the abnormality determination processing is executed only in a case where the change in the load due to inclination is within ±10%.

[0133] According to the second embodiment described above, the following action and effect are exhibited.

[0134] The processor 2a of the controller 202 computes the abnormality determination evaluation value on the basis of the differential pressure value ΔP between the first pump pressure P1 and the second pump pressure P2. It should be noted that in the present embodiment, the differential pressure value ΔP is employed for the abnormality determination evaluation value. Where the absolute value |φ| of the roll angle (the inclination angle of the machine body 107) φ of the lower track structure 101 is equal to or smaller than the predetermined angle φt and the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is larger than the determination reference value ΔP0, the processor 2a of the controller 202 determines that there is an abnormality in either one of the left travel device 50 and the right travel device 60. When it is determined that there is an abnormality, the processor 2a of the controller 202 outputs the determination result to the output device (the display device 91 and the communication device 92). When the absolute value |φ| of the roll angle (the inclination angle of the machine body 107) φ of the lower track structure 101 is larger than the predetermined angle φt, or when the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is equal to or smaller than the determination reference value ΔP0, the processor 2a of the controller 202 does not determine that there is an abnormality in either one of the left travel device 50 and the right travel device 60.

[0135] According to this configuration, where the inclination angle of the inclined road surface 109b, that is, the roll angle φ of the lower track structure 101 is equal to or smaller than the predetermined angle φt, the abnormality determination processing is executed on the basis of the differential pressure value ΔP. On the other hand, where the roll angle φ of the lower track structure 101 is larger than the predetermined angle φt, the abnormality determination processing based on the differential pressure value ΔP is not executed. Accordingly, it is possible to suppress erroneous detection of an abnormality caused by execution of the abnormality determination processing in a situation that is easily affected by the inclination angle of the inclined road surface 109b. That is, in the second embodiment, it is possible to provide the hydraulic excavator 100 capable of preventing erroneous detection of an abnormality of the travel devices 50 and 60 when travelling on the inclined road surface 109b as similar to the first embodiment. According to the present embodiment, the influence of the inclination on the abnormality determination processing can be eliminated, and the abnormality of the travel devices 50 and 60 can be accurately detected.<Third Embodiment>

[0136] A hydraulic excavator 100 according to a third embodiment of the present invention will be described with reference to Fig. 16 to Fig. 19. It should be noted that the same reference symbols are given to the configurations same as or corresponding to those described in the second embodiment, and differences will be mainly described.

[0137] In the first embodiment and the second embodiment, an example in which the roll angle φ of the lower track structure 101 is sensed by the inclination angle sensor 76 attached to the lower track structure 101 has been described. On the other hand, in the third embodiment, the roll angle φ of the lower track structure 101 is indirectly sensed on the basis of a sensed result of a swing structure inclination angle sensor 376a attached to the upper swing structure 102 and the swing angle of the upper swing structure 102 with respect to the lower track structure 101. That is, the swing structure inclination angle sensor 376a and the swing angle sensor 376b configure an inclination angle sensing device 376 of the lower track structure 101. The upper swing structure 102 has the operation room 110 and the enclosure for storing the engine and the like, and is better in installation property of sensors and the like compared with the lower track structure 101. In addition, it is also excellent in environment resistance.

[0138] Fig. 16 is a schematic view for depicting inclination angles (a roll angle φtrv and a pitch angle θtrv) of the lower track structure 101 and inclination angles (a roll angle φswg and a pitch angle θswg) of the upper swing structure 102.

[0139] As depicted in Fig. 16, in the hydraulic excavator 100, for example, a track structure reference coordinate system that is a coordinate system using the lower track structure 101 as a reference and a swing structure reference coordinate system that is a coordinate system using the upper swing structure 102 as a reference are set. Fig. 16 schematically depicts the relationship between the track structure reference coordinate system and the swing structure reference coordinate system.

[0140] The track structure reference coordinate system corresponds to the machine body coordinate system described in the first embodiment. The track structure reference coordinate system is defined as a right-handed coordinate system using as the origin an arbitrary point on the swing centerline that is the rotation axis of the upper swing structure 102. In the track structure reference coordinate system, the forward direction of the lower track structure 101 is defined as the positive direction of the Xtrv axis. In the track structure reference coordinate system, the vertically upper direction along the swing centerline is defined as the positive direction of the Z axis. In the track structure reference coordinate system, the left direction of the lower track structure 101 orthogonal to each of the Xtrv axis and the Z axis is defined as the positive direction of the Ytrv axis.

[0141] The swing structure reference coordinate system is defined as a right-handed coordinate system using as the origin an arbitrary point on the swing centerline that is the rotation axis of the upper swing structure 102. In the swing structure reference coordinate system, the front direction of the upper swing structure 102 is defined as the positive direction of the Xswg axis. In the swing structure reference coordinate system, the vertically upper direction along the swing centerline is defined as the positive direction of the Z axis. In the swing structure reference coordinate system, the left direction of the upper swing structure 102 orthogonal to each of the Xswg axis and the Z axis is defined as the positive direction of the Ysyg axis.

[0142] The Z axis of the track structure reference coordinate system and the Z axis of the swing structure reference coordinate system are common. The rotation angle in the Xtrv-Z plane orthogonal to the Ytrv axis is represented by the pitch angle θtrv of the lower track structure 101. The rotation angle in the Xtrv-Ytrv plane orthogonal to the Z axis is represented by the yaw angle ψtrv of the lower track structure 101. The rotation angle in the Ytrv-Z plane orthogonal to the Xtrv axis is represented by the roll angle φtrv of the lower track structure 101. The Xtrv axis is an axis along the advancing direction of the lower track structure 101, and the roll angle φtrv with the Xtrv axis as the rotation axis corresponds to the lateral inclination angle of the lower track structure 101 with respect to the horizontal plane. The Ytrv axis is an axis parallel to the rotation axes of the travelling motors 31 and 32, and the pitch angle θtrv with the Ytrv axis as the rotation axis corresponds to the longitudinal inclination angle of the lower track structure 101 with respect to the horizontal plane.

[0143] The rotation angle in the Xswg-Z plane orthogonal to the Yswg axis is represented by the pitch angle θswg of the upper swing structure 102. The rotation angle in the Xswg-Yswg plane orthogonal to the Z axis is represented by the yaw angle ψswg of the upper swing structure 102. The rotation angle in the Yswg-Z plane orthogonal to the Xswg axis is represented by the roll angle φ of the upper swing structure 102. The Xswg axis is an axis along the front of the upper swing structure (the front of the operation room 110), and the roll angle φ with the Xswg axis as the rotation axis corresponds to the lateral inclination angle of the upper swing structure 102 with respect to the horizontal plane. The Yswg axis is an axis parallel to the rotation axis of the boom 104, and the pitch angle θswg with the Yswg axis as the rotation axis corresponds to the longitudinal inclination angle of the upper swing structure 102 with respect to the horizontal plane. It should be noted that the difference between the yaw angle ψtrv of the lower track structure 101 and the yaw angle ψswg of the upper swing structure 102 corresponds to the swing angle ψ.

[0144] The upper swing structure 102 rotates relative to the lower track structure 101. Therefore, when the direction of the upper swing structure 102 and the direction of the lower track structure 101 do not coincide with each other, the inclination angle of the upper swing structure 102 and the inclination angle of the lower track structure 101 are not equal to each other. For example, when the roll angle φswg of the upper swing structure 102 is 10°, the relationship between the swing angle ψ and the roll angle φtrv of the lower track structure 101 and the relationship between the swing angle ψ and the pitch angle θtrv of the lower track structure 101 are represented by graphs depicted in Fig. 17.

[0145] The roll angle (hereinafter, also referred to as a track structure roll angle) φtrv of the lower track structure 101 is represented by an equation (17). In addition, the pitch angle (hereinafter, also referred to as a track structure pitch angle) θtrv of the lower track structure 101 is represented by an equation (18). φtrv = φswg × cosψ + θswg × sinψ φtrv = φswg × sinψ + θswg × cosψ

[0146] As depicted in Fig. 16, φswg is the roll angle (hereinafter, also referred to as a swing structure roll angle) of the upper swing structure 102, θswg is the pitch angle (hereinafter, also referred to as a swing structure pitch angle) of the upper swing structure 102, and ψ is the swing angle.

[0147] Fig. 18 is a diagram similar to that of Fig. 13 and is a functional block diagram of a controller 302 according to the third embodiment. The controller 302 has an inclination state determination section 377 instead of the inclination state determination section 277 of the controller 202 according to the second embodiment. A processor 2a of the controller 302 realizes these functions by executing the programs stored in the non-volatile memory 2b.

[0148] The inclination angle sensing device (inclination state sensor) 376 has a swing structure inclination angle sensor 376a, a swing angle sensor 376b, and an inclination calculation section 378. The swing structure inclination angle sensor 376a senses the inclination angle of the upper swing structure 102 with respect to a reference plane (for example, a horizontal plane) and outputs a signal representing the sensed result to the inclination calculation section 378. The swing angle sensor 376b is provided in the machine body 107, senses the swing angle ψ that is the rotation angle of the upper swing structure 102 with respect to the lower track structure 101, and outputs a signal representing the sensed result to the inclination calculation section 378. The swing structure inclination angle sensor 376a can employ an IMU (Inertial Measurement Unit) that acquires angular velocities and accelerations of orthogonal three axes as information related to the posture, computes the inclination angles (the swing structure roll angle φswg and the swing structure pitch angle θswg) on the basis of the information, and outputs signals representing the inclination angles φswg and θswg to the inclination calculation section 378. The inclination calculation section 378 calculates the track structure roll angle φtrv on the basis of the information (the swing structure roll angle φswg, the swing structure pitch angle θswg, and the swing angle ψ) representing the posture of the upper swing structure 102. The inclination calculation section 378 is configured with a microcomputer (computation device) having a processor such as a CPU, and a memory such as a ROM and a RAM. It should be noted that the function of the inclination calculation section 378 may be provided in the controller 302 that is a computation device.

[0149] Fig. 19 is a diagram similar to that of Fig. 15 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller 302 according to the third embodiment. In the flowchart of Fig. 19, processing of Step S307 is added between Step S2 and Step S10 of the flowchart of Fig. 15.

[0150] As depicted in Fig. 19, when the differential pressure calculation processing (Step S2) is terminated, the processing proceeds to Step S307. In Step S307, the inclination state determination section 377 acquires the track structure roll angle φ calculated by the inclination calculation section 378. It should be noted that the inclination calculation section 378 acquires the swing structure roll angle φswg, the swing structure pitch angle θswg, and the swing angle ψ sensed by the inclination angle sensing device 376 at a predetermined computation cycle, calculates the track structure roll angle φtrv, and outputs it to the controller 302.

[0151] According to the third embodiment described above, the following action and effect are exhibited in addition to the similar action and effect of the second embodiment.

[0152] The inclination angle sensing device (inclination state sensor) 376 includes the swing structure inclination angle sensor 376a that is attached to the upper swing structure 102 and senses the inclination angles (the roll angle φswg and the pitch angle θswg) of the upper swing structure 102 with respect to the horizontal plane, the swing angle sensor 376b that senses the swing angle ψ of the upper swing structure 102 with respect to the lower track structure 101, and the inclination calculation section (computation device) 378 that computes the roll angle φtrv that is the inclination angle of the lower track structure 101 in the lateral direction with respect to the horizontal plane on the basis of the inclination angles φswg and θswg of the upper swing structure 102 sensed by the swing structure inclination angle sensor 376a and the swing angle ψ of the upper swing structure 102 sensed by the swing angle sensor 376b. When the absolute value |φtrv| of the roll angle φtrv of the lower track structure 101 sensed by the inclination angle sensing device 376 is equal to or smaller than the predetermined angle φt and the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is larger than the determination reference value ΔP0, the processor 2a of the controller 302 determines that there is an abnormality in either one of the left travel device 50 and the right travel device 60. Where the absolute value |φtrv| of the roll angle φtrv of the lower track structure 101 sensed by the inclination angle sensing device 376 is larger than the predetermined angle φt or where the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is equal to or smaller than the determination reference value ΔP0, the processor 2a of the controller 302 does not determine that there is an abnormality in either one of the left travel device 50 and the right travel device 60.

[0153] The lower track structure 101 has a mechanism for rotatably coupling the upper swing structure 102, and it is not easy to install a sensor and the like. In the third embodiment, it is not necessary to install the inclination angle sensor 76 in the lower track structure 101. Therefore, the configuration of the hydraulic excavator 100 can be simplified and the manufacturing cost can be reduced.<Fourth Embodiment>

[0154] A diagnostic system 410 according to a fourth embodiment of the present invention will be described with reference to Fig. 20 and Fig. 21. It should be noted that the same reference symbols are given to the configurations same as or corresponding to those described in the first embodiment, and differences will be mainly described.

[0155] The hardware configuration of a hydraulic excavator 400 is similar to that of the hydraulic excavator 100 described in the first embodiment. In the first embodiment, an example in which the diagnostic device 80 includes the controller 2 mounted on the hydraulic excavator 100 and the output device (the display device 91 and the communication device 92) has been described. On the other hand, in the fourth embodiment, a diagnostic device 480 includes a server 440 provided in a management facility and an output device (a display device 462 and a communication device 498). That is, in the fourth embodiment, the server 440 diagnoses an abnormality of the travel devices 50 and 60 of the hydraulic excavator 400 on the basis of feature amounts acquired from one or more hydraulic excavators 100. Therefore, a controller 402 of the hydraulic excavator 400 has a function of computing feature amounts but does not have a function of diagnosing an abnormality.

[0156] In the fourth embodiment, processing of collecting feature amounts from a plurality of hydraulic excavators 100 and performing analysis, comparison, and judgement can be handled simultaneously or in combination. Therefore, it is possible to analyze and diagnose data overviewing the entirety.

[0157] Fig. 20 is a diagram for depicting a configuration of the diagnostic system 410 according to the fourth embodiment. The diagnostic system 410 includes one or more hydraulic excavators 400 for conducting work at a work site and the diagnostic device 480 provided in a management facility. The management facility is provided at a place away from the work site. The hydraulic excavator 400 and the diagnostic device 480 are configured to be capable of performing bidirectional communication via a communication line NT of a wide area network. That is, the hydraulic excavator 400 and the diagnostic device 480 can transmit and receive information (data) via the communication line NT. The communication line NT is a mobile phone communication network (mobile communication network) developed by a mobile carrier and the like, a satellite communication network, the Internet, or the like. The diagnostic device 480 includes the server 440, an input device 461, the display device 462, and the communication device 498.

[0158] The controller 402 mounted on the hydraulic excavator 400 and the server 440 installed in the management facility are computers provided with processors 402a and 440a such as CPUs, non-volatile memories 402b and 440b that are storage devices (memories), and volatile memories 402c and 440c, respectively, as similar to the controller 2 of the first embodiment. In addition, the controller 402 and the server 440 are provided with input interfaces 402d and 440d and output interfaces 402e and 440e, respectively. It should be noted that each of the controller 402 and the server 440 may be configured by one computer or a plurality of computers.

[0159] The server 440 collects feature amounts (a travelling feature amount and an inclination feature amount) from the hydraulic excavator 400 via the communication device 498 as a receiver. The server 440 analyzes the tendency of the operation and deterioration of the hydraulic excavator 400 from time-series behaviors of the feature amounts, compares the feature amounts with a threshold value, and makes various determinations. In addition, the server 440 compares the feature amounts of the plurality of hydraulic excavators 400 with each other to identify a hydraulic excavator 400 that is transmitting a feature amount deviated from the average feature amount, and conducts various analyses on the basis of the degree of the deviation of the feature amount. Further, the server 440 can make various determinations using other statistical analysis methods or the like.

[0160] The display device 462 such as a liquid crystal monitor, the input device 461 such as a keyboard, and the communication device 498 for exchanging information with each hydraulic excavator 400 via the communication line NT are connected to the server 440. The display device 462 is an output device that is controlled by the server 440 and outputs a computation result of the server 440 as an image. The communication device 498 is an output device that is connected to the communication line NT and outputs the computation result of the server 440 to the hydraulic excavator 400.

[0161] In the first embodiment depicted in Fig. 10, the controller 2 may calculate the abnormality determination evaluation value (corrected differential pressure value ΔPc) from the first pump pressure P1, the second pump pressure P2, and the machine body roll angle φ, and transmit the abnormality determination evaluation value to the server 40 via the communication device 92. In addition, the server 40 according to the first embodiment may have an analysis function of performing storing, analysis, comparison, and determination regarding the acquired data. If an abnormality is found by analysis, the server 40 displays information of the hydraulic excavator 100 in which the abnormality has been found on the display device such as a liquid crystal monitor. Accordingly, the vehicle manager can easily identify the hydraulic excavator 100 in which the abnormality has occurred. In addition, the server 40 may transmit information for informing that the abnormality has occurred to the hydraulic excavator 100 in which the abnormality has been found, or may transmit information for informing that the abnormality has occurred to the vehicle manager, the operator, or the like by using notification means such as an e-mail. However, where such a system is used, handling in operation management may be complicated.

[0162] For example, in the first embodiment, the abnormality determination evaluation value and the determination reference value are compared with each other and the presence or absence of an abnormality is determined, in each of the plurality of hydraulic excavators 100. Here, the correction amount Pc according to the roll angle φ of the hydraulic excavator 100 is used for calculation of the abnormality determination evaluation value. Although the coefficient (for example, the loss torque coefficient C) and the load characteristic table T used for calculation of the correction amount Pc may be set in advance on the basis of design values or the tendency of past measurement data as in the first embodiment, it is preferable to acquire and adjust actual operation information of the hydraulic excavator 100. Therefore, the correction amount parameters (for example, the loss torque coefficient C and the load characteristic table T) necessary for calculating the correction amount Pc may be reviewed while confirming the operation information of the hydraulic excavator 100 in the early stage of operation.

[0163] This review work of the correction amount parameters is useful because an appropriate correction amount PC can be obtained. However, in the first embodiment, the calculation of the correction amount Pc and the correction processing using the correction amount Pc are performed by the controller 2 of each hydraulic excavator 100. Therefore, in order to modify the correction amount parameters necessary for calculating the correction amount Pc or to change the correction logic (correction method), modification work (rewriting work) of software is necessary for each of the plurality of the hydraulic excavators 100. For example, where the correction amount parameters need to be modified in a certain model of the hydraulic excavator 100, software needs to be similarly modified for all of the corresponding hydraulic excavators 100, which requires a lot of time and effort. In addition, it becomes necessary to monitor the operation of the hydraulic excavator 100 with the correction amount parameters modified to confirm whether the modification is appropriate in each of the plurality of hydraulic excavators 100, which requires a lot of time and effort for management work.

[0164] In contrast, in the diagnostic system 410 according to the fourth embodiment, the work of modifying the correction amount parameters and changing the correction logic (correction method) can be easily conducted, and further, management after the modification can be easily performed. The details thereof will be described below.

[0165] Fig. 21 is a functional block diagram of the diagnostic system 410 according to the fourth embodiment. As depicted in Fig. 21, the controller 402 has a state determination section 70, a travelling state amount calculation section 495, an inclination state amount calculation section 496, and a feature amount computation section 482. A processor 402a of the controller 402 realizes these functions by executing the programs stored in the non-volatile memory 402b. In addition, the server 440 has a correction amount calculation section 483, a feature amount correction section 481, an analysis section 490, and a modification section 499. The processor 440a of the server 440 realizes these functions by executing the programs stored in the memory 440b.

[0166] The travelling state amount calculation section 495 stabilizes the pressure sensor values (sensor data representing the first pump pressure P1 and the second pump pressure P2) output from the first pressure sensor 13 and the second pressure sensor 23 by a stabilizing filter or the like, and calculates a travelling state amount equivalent to the travel driving force on the basis of the stabilized pressure sensor values.

[0167] The inclination state amount calculation section 496 stabilizes the inclination angle sensor value (sensor data representing the roll angle φ) output from the inclination angle sensor 76 by a stabilizing filter or the like, and calculates an inclination state amount equivalent to the roll angle φ of the machine body 107 on the basis of the stabilized inclination angle sensor value.

[0168] It is necessary to synchronize the travelling state amount and the inclination state amount with each other. Therefore, the characteristics of the stabilizing filters used in the travelling state amount calculation section 495 and the inclination state amount calculation section 496 have equal response characteristics. The travelling state amount calculation section 495 and the inclination state amount calculation section 496 output the travelling state amount and the inclination state amount in synchronization with each other.

[0169] The feature amount computation section 482 computes the travelling feature amount and the inclination feature amount on the basis of the travelling state amount calculated by the travelling state amount calculation section 495, the inclination state amount calculated by the inclination state amount calculation section 496, and the determination result by the state determination section 70. The feature amount computation section 482 extracts, as the travelling feature amount, the travelling state amount calculated at the time when the valid mode is set by the state determination section 70. That is, in the fourth embodiment, the travelling feature amount indicates a travelling state amount to be transmitted to the server 440. Similarly, the feature amount computation section 482 extracts, as the inclination feature amount, the inclination state amount calculated at the time when the valid mode is set by the state determination section 70. That is, in the fourth embodiment, the inclination feature amount indicates an inclination state amount to be transmitted to the server 440.

[0170] The feature amount computation section 482 transmits feature amount data in which the travelling feature amount and the inclination feature amount, the time at which the sensor values used for computing them have been acquired, and a vehicle ID for identifying the hydraulic excavator 400 are associated with each other to the server 440 via the communication device (transmitter) 92. The server 440 acquires feature amount data from each hydraulic excavator 400 via the communication device (receiver) 498.

[0171] The travelling feature amount may be sensor data itself output from the travelling state sensor provided in the hydraulic excavator 400 or calculation data calculated on the basis of the sensor data. Similarly, the inclination feature amount may be sensor data itself output from the inclination state sensor or calculation data calculated on the basis of the sensor data.

[0172] The correction amount calculation section 483 calculates a correction amount related to the travelling feature amount from the inclination feature amount, and outputs it. When each of the inclination state amount and the inclination feature amount is the roll angle φ, the correction amount calculation section 483 calculates the correction amount Pc by the method similar to the method used by the correction amount calculation section 83 of the first embodiment.

[0173] The feature amount correction section 481 corrects the travelling feature amount on the basis of the correction amount Pc and outputs it. When each of the travelling state amount and the travelling feature amount is the differential pressure value ΔP between the first pump pressure P1 and the second pump pressure P2, the feature amount correction section 481 calculates the corrected differential pressure value ΔPc as the abnormality determination evaluation value by the method similar to the method used by the differential pressure value calculation section 81 of the first embodiment.

[0174] The analysis section 490 acquires the corrected differential pressure value ΔPc that is the corrected travelling feature amount and analyzes it. For example, the analysis section 490 makes the abnormality determination by the method similar to the method used by the abnormality determination section 90 described in the first embodiment. When it is determined that there is an abnormality in the travel device 50 or 60, the analysis section 490 outputs the vehicle ID of the hydraulic excavator 400 provided with the travel device 50 or 60 and notification information for informing that an abnormality has occurred in the travel device 50 or 60 to the display device 491 and the sound output device 492.

[0175] The display device 491 displays a notification screen for informing that an abnormality has occurred. The notification screen includes information of the vehicle ID of the hydraulic excavator 400 in which the abnormality has occurred and the travel device (the left travel device 50 or the right travel device 60) in which the abnormality has occurred. The notification screen may include information on the travelling feature amount and the inclination feature amount. The sound output device 492 is, for example, a speaker for outputting the notification information by using voice. It should be noted that the sound output device 492 may be a device for outputting an alarm sound in a preset output pattern according to the notification information.

[0176] Accordingly, the vehicle manager can quickly grasp the hydraulic excavator 400 in which the abnormality has occurred. It should be noted that the analysis section 490 may transmit the notification information via the communication device 498 to the hydraulic excavator 400 in which the abnormality has occurred or an information terminal (for example, a tablet terminal, a smartphone, or a laptop) possessed by the operator of the hydraulic excavator 400.

[0177] The modification section 499 judges the necessity of the modification of the correction amount parameters on the basis of the travelling feature amount, the inclination feature amount, the current correction amount parameter, and the analysis result. The modification section 499 modifies the correction amount parameters when it is judged that the modification of the correction amount parameters is necessary. For example, where a deviation occurs to some extent after checking the appropriateness of the analysis result, the modification section 499 judges that the correction amount parameters need to be altered and adjusted, and performs adjustment processing of the correction amount parameters. For example, the characteristics of the travelling feature amount and the inclination feature amount closer to the true value and matching the actual condition can be obtained by increasing or recalculating the number of data parameters.

[0178] Accordingly, where it is necessary to modify the correction amount parameters, it can be handled by modifying software of the server 440. Accordingly, it is not necessary to conduct work such as modification of software for each of the plurality of hydraulic excavators 400, and the correction amount parameters can be easily modified on the server 440 side. In addition, by only partially modifying the software of the server 440, it is possible to cope with all the hydraulic excavators 400 to be diagnosed, and there is no need to perform rewriting management for each hydraulic excavator 400, which is preferable.

[0179] It should be noted that, although an example in which the server 440 performs automatic modification has been described above, the vehicle manager or the service person may manually modify the correction amount parameters as necessary by using the input device 461.

[0180] As described above, the diagnostic device 480 according to the fourth embodiment is provided with the server 440 provided with the processor (first processor) 440a for diagnosing an abnormality of the travel devices 50 and 60 on the basis of the travelling feature amount (differential pressure value ΔP) representing the travelling states of the travel devices 50 and 60 mounted to the machine body 107 of the hydraulic excavator 400, and the output device (the display device 462 and the communication device 498) for outputting the result of the diagnosis by the processor 440a. The processor 440a acquires the inclination feature amount (roll angle φ) representing the inclination state of the machine body 107. The processor 440a computes the correction amount Pc for canceling the influence of the inclination state of the machine body 107 on the travelling feature amounts (differential pressure value ΔP) of the travel devices 50 and 60 on the basis of the inclination feature amount (roll angle φ). The processor 440a computes the corrected travelling feature amount (corrected differential pressure value ΔPc) by correcting the travelling feature amount (differential pressure value ΔP) on the basis of the correction amount Pc. The processor 440a computes the abnormality determination evaluation value on the basis of the corrected travelling feature amount (corrected differential pressure value ΔPc). The processor 440a determines whether or not there is an abnormality in the travel devices 50 and 60 on the basis of the abnormality determination evaluation value. When it is determined that there is an abnormality, the processor 440a outputs the determination result to the output device (display device 462).

[0181] According to the diagnostic system 410, an abnormality of the hydraulic excavator 400 is diagnosed by the server 440, and an image representing the diagnosis result is output by the display device (output device) 462. Therefore, the vehicle manager can easily identify the hydraulic excavator 400 in which an abnormality has occurred and can quickly and appropriately make a maintenance plan for eliminating the abnormality.

[0182] The diagnostic system 410 according to the fourth embodiment includes the diagnostic device 480 and the hydraulic excavator (work machine) 400. The diagnostic device 480 is provided with the communication device (receiver) 498 and the server 440. The communication device 498 receives the travelling feature amount (differential pressure value ΔP) and the inclination feature amount (roll angle φ) transmitted from the hydraulic excavator 400. The server 440 has the processor (first processor) 440a for diagnosing an abnormality of the travel devices 50 and 60 of the hydraulic excavator 400 on the basis of the travelling feature amount and the inclination feature amount received by the communication device 498, and the non-volatile memory (memory) 402b for storing the correction amount parameters (the loss torque coefficient C and the load characteristic table T) used for computation of the correction amount Pc. The hydraulic excavator 400 is provided with the travelling state sensor (the first pressure sensor 13 and the second pressure sensor 23) for sensing the travelling states of the travel devices 50 and 60, the inclination state sensor (inclination angle sensor 76) for sensing the inclination state of the machine body 107, the processor (second processor) 402a for computing the travelling feature amount (differential pressure value ΔP) on the basis of a sensor value representing the travelling state sensed by the travelling state sensor and computing the inclination feature amount (roll angle φ) on the basis of a sensor value representing the inclination state sensed by the inclination state sensor, and the communication device (transmitter) 92 for transmitting the travelling feature amount (differential pressure value ΔP) and the inclination feature amount (roll angle φ) computed by the processor 402a to the server 440. The processor 402a computes the travelling feature amount (differential pressure value ΔP) and the inclination feature amount (roll angle φ) in synchronization with each other. The processor 440a computes the correction amount Pc on the basis of the correction amount parameters (the loss torque coefficient C and the load characteristic table T) stored in the non-volatile memory 402b and the inclination feature amount (roll angle φ).

[0183] In this configuration, since the correction amount parameters are stored in the server 440, the service person can easily modify the correction amount parameters. In other words, in the present embodiment, it is not necessary for the service person to modify the correction amount parameters in each of the plurality of hydraulic excavators.<Modified example of fourth embodiment>

[0184] In a modified example of the fourth embodiment, a configuration in a case where the communication cycle of data is slow will be described. Various types of communication cycles of data are assumed according to data. For example, where data is transmitted in real time, the communication cycle of the data is set to approximately several tens of Hz. In addition, where daily report data is transmitted, the communication cycle of the data is set to one day. In the modified example of the fourth embodiment, an example suitable for a case where the transmission cycle of data of the hydraulic excavator 400 is long will be depicted.

[0185] In monitoring diagnosis of a machine state such as abnormality diagnosis of the travel device of the hydraulic excavator 400, the condition of the machine body can be sufficiently expressed even if the state is grasped once a day such as a daily report because of being familiar with the daily inspection of the machine body 107. Where the communication cycle of data is approximately once a day, the amount of communication can be largely reduced as compared with a case where data is transmitted in real time. For example, where data is transmitted as a daily report, the data is thinned to one data per day for each item, and the data is transmitted at a frequency of once a day. In this case, the communication cycle from the communication device (transmitter) 92 to the communication device (receiver) 498 is one day (24 hours), and the data on the server 440 side becomes daily down-sampled data.

[0186] On the other hand, there is a demand to perform statistical processing, filter processing, and the like by the analysis section 490 of the server 440 for the purpose of analysis such as confirmation of the behavior and tendency of data such as the acquired feature amount. However, the sampling frequency of data may have an adverse effect (influence of aliasing). Specifically, when sampling a signal, it is necessary to consider the relationship of the Nyquist frequency, and there is a restriction that "only half the sampling frequency can be reproduced." Therefore, in the case of a characteristic including a band to be restricted, it is necessary to perform filtering processing (corresponding to an anti-aliasing filter) for suppressing the influence before down-sampling. The anti-aliasing filter is a low-pass filter that attenuates frequencies above half the sampling frequency with high attenuation characteristics. By sampling a signal having passed through the anti-aliasing filter, the occurrence of aliasing is prevented.

[0187] Fig. 22 is a conceptual diagram for calculating data by down-sampling after applying a filter for feature extraction. The feature amount computation section 482 (see Fig. 21) performs down-sampling after an output value of a filter or the like is appropriately calculated. The feature amount computation section 482 down-samples the output value at three types of cycles. As depicted in Fig. 22, the three types of cycles include a first cycle (hereinafter, a short term) S, a second cycle (hereinafter, a medium term) M, and a third cycle (hereinafter, a long term L), and the magnitude relationship is "short term S < medium term M < long term L."

[0188] As depicted in Fig. 22, a dynamic response for feature extraction from original data is generated and output by a dynamic filter that acquires tendencies in the short term S, the medium term M, and the long term L. Each of these output values is down-sampled as a daily report and output to the server 440. According to the configuration of the modified example of the fourth embodiment, for example, an appropriate value can be calculated even for a behavior in a relatively short term and used for analysis.

[0189] The controller 402 according to the modified example of the fourth embodiment calculates the travelling feature amounts on the basis of sensor data sampled at the respective cycles of the short term S, the medium term M, and the long term L in accordance with a dynamic response characteristic required at the time of analysis, and transmits the respective calculated values to the server 440. It should be noted that since the inclination data is also similarly treated as explanatory variables, the inclination feature amount having the similar response characteristic is calculated and is similarly transmitted as a daily report so that the response is synchronized. That is, the controller 402 calculates the inclination feature amounts on the basis of sensor data sampled at the respective cycles of the short term S, the medium term M, and the long term L, and transmits the respective calculated values to the server 440.

[0190] The controller 402 calculates the travelling feature amount and the inclination feature amount that are synchronized with each other in the short term S and transmits them to the server 440. In addition, the controller 402 calculates the travelling feature amount and the inclination feature amount that are synchronized with each other in the medium term M and transmits them to the server 440. Further, the controller 402 calculates the travelling feature amount and the inclination feature amount that are synchronized with each other in the long term L and transmits them to the server 440.

[0191] Accordingly, in the analysis section 490 of the server 440, the travelling feature amount and the inclination feature amount having a desired response characteristic can be used in a synchronized manner, and thus they can be used as excellent feature amounts without causing phase shift of each data or the like.

[0192] As described above, in the modified example of the fourth embodiment, the processor (second processor) 402a of the hydraulic excavator 400 computes the travelling feature amount and the inclination feature amount for each of the plurality of cycles (the short term S, the medium term M, and the long term L). The processor (first processor) 440a of the server 440 can compute the abnormality determination evaluation value for each of the plurality of cycles (the short term S, the medium term M, and the long term L) on the basis of the travelling feature amount and the inclination feature amount for each of the plurality of cycles (the short term S, the medium term M, and the long term L).

[0193] According to this configuration, the abnormality diagnosis can be performed by using the abnormality determination evaluation value computed on the basis of the travelling feature amount and the inclination feature amount having a desired response characteristic. That is, the convenience of the diagnostic device 480 can be improved.

[0194] According to the configurations of the fourth embodiment and the modified example of the fourth embodiment, since the condition judgement logic can be performed on the server side, the feature amount can be computed and updated regardless of the inclination condition, and the correction amount parameters can be easily adjusted while checking the degree of the feature amount. In addition, the rewriting work or the like of the software of the controller 402 is unnecessary, and the repair work and maintenance management work for the machine body are largely reduced.

[0195] In addition, since it is possible to collect the travelling feature amounts and the inclination feature amounts of the plurality of hydraulic excavators 400 and analyze the behaviors of these feature amounts, it is possible to appropriately and easily set correction conditions such as the necessity of modification of the correction amount parameters and the correction logic (correction method) and the modification amount of the correction parameters. Further, the appropriateness of the setting of the correction conditions can be easily judged by monitoring the behaviors of the travelling feature amounts and the inclination feature amounts collected after the setting of the correction conditions.

[0196] The following modified examples are also within the scope of the present invention, and it is possible to combine the configurations to be depicted in the modified examples with the configurations described in the above embodiments, to combine the configurations described in the above different embodiments with each other, and to combine the configurations to be described in the following different modified examples with each other.<Modified example 1>

[0197] In the first embodiment, the abnormality determination of the travel devices 50 and 60 is executed by performing correction regardless of the roll angle φ of the lower track structure 101. However, if the roll angle φ is too large, there is a risk that the abnormality determination cannot be accurately made even where correction has been performed. Thus, in a modified example 1, the correction processing described in the first embodiment is executed only in a case where the inclination angle is within a predetermined angle range, and the abnormality determination of the travel devices 50 and 60 is performed on the basis of the corrected differential pressure value ΔPc as the abnormality determination evaluation value. The modified example 1 corresponds to an example obtained by combining the first embodiment and the second embodiment with each other.

[0198] Fig. 23 is a diagram similar to those of Fig. 12 and Fig. 15 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by a controller 2 according to the modified example 1. In the flowchart depicted in Fig. 23, the processing of Step S245 of the flowchart of Fig. 15 is added between Step S40 and Step S50 of the flowchart of Fig. 12. The processing of Steps S2 to S40 and Steps S50 to S110 is similar to that of the first embodiment, and the processing of Step S245 is similar to that of the second embodiment.

[0199] Where the absolute value |φ| of the roll angle φ of the lower track structure 101 sensed by the inclination angle sensor 76 is equal to or smaller than the predetermined angle φt and the absolute value |ΔPc| of the corrected differential pressure value ΔPc as the abnormality determination evaluation value is larger than the determination reference value ΔP0, the processor 2a of the controller 2 according to the modified example 1 determines that there is an abnormality in either one of the left travel device 50 and the right travel device 60. Where the absolute value |φ| of the roll angle φ of the lower track structure 101 sensed by the inclination angle sensor 76 is larger than the predetermined angle φt and the absolute value |ΔPc| of the corrected differential pressure value ΔPc as the abnormality determination evaluation value is equal to or smaller than the determination reference value ΔP0, the processor 2a of the controller 2 does not determine that there is an abnormality in either one of the left travel device 50 and the right travel device 60. According to this configuration, it is possible to more appropriately prevent erroneous detection of an abnormality of the travel devices 50 and 60.<Modified example 2>

[0200] Although an example in which the inclination angle sensor 76 is provided in the lower track structure 101 has been described in the second embodiment, the swing structure inclination angle sensor 376a described in the third embodiment may be provided in the upper swing structure 102, and the inclination angle sensor 76 of the lower track structure 101 may be omitted. If the direction (for example, the longitudinal direction) of the upper swing structure 102 is substantially the same as the direction (for example, the longitudinal direction) of the lower track structure 101, the roll angle φswg sensed by the swing structure inclination angle sensor 376a of the upper swing structure 102 can be regarded as the roll angle φtrv of the lower track structure 101.

[0201] Fig. 24 is a diagram similar to that of Fig. 15 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by a controller 202 according to a modified example 2. In the flowchart of Fig. 24, processing of Step S543 is added between Step S40 and Step S245 of the flowchart of Fig. 15.

[0202] As depicted in Fig. 24, when positive determination is made in Step S40, the processing proceeds to Step S543. In Step S543, the controller 202 determines whether or not the swing angle ψ sensed by the swing angle sensor 376b is within a predetermined swing angle range. When the hydraulic excavator 100 is in a reference posture, the swing angle ψ is 0°. The reference posture corresponds to a posture in which the direction of the lower track structure 101 and the direction of the upper swing structure 102 coincide with each other. When the upper swing structure 102 swings to the right from the state of the reference posture, the swing angle ψ increases from 0° to 180° according to the swing. When the upper swing structure 102 swings to the left from the state of the reference posture, the swing angle ψ decreases from 0° to -180° according to the swing (the absolute value increases).

[0203] Where the roll angle φswg of the upper swing structure 102 is set to the roll angle φtrv of the lower track structure 101, the predetermined swing angle range is set to such an angle range that erroneous detection of an abnormality of the travel devices 50 and 60 does not occur. That is, the predetermined swing angle range is set in order to determine that it is in the reference posture, and is set to, for example, -10° or more and +10° or less.

[0204] As described above, the hydraulic excavator 100 according to the modified example 2 is provided with the swing angle sensor 376b for sensing the swing angle ψ of the upper swing structure 102 with respect to the lower track structure 101, and the swing structure inclination angle sensor (the inclination state sensor and the inclination angle sensor) 376a attached to the upper swing structure 102 to sense the roll angle (inclination angle) φ of the upper swing structure 102 with respect to the horizontal plane. It should be noted that, when the directions of the upper swing structure 102 and the lower track structure 101 coincide with each other, the roll angle φswg of the upper swing structure 102 coincides with the roll angle φtrv of the lower track structure 101. The processor 2a of the controller 202 determines whether or not the swing angle ψ sensed by the swing angle sensor 376b is within a predetermined swing angle range (-ψt ≤ ψ ≤ ψt) including the swing angle (0°) at which the direction of the lower track structure 101 and the direction of the upper swing structure 102 coincide with each other. Where the swing angle ψ is within the predetermined swing angle range, the absolute value |φ| of the roll angle (inclination angle) φ of the upper swing structure 102 sensed by the swing structure inclination angle sensor 376a is equal to or smaller than the predetermined angle φt and the absolute value |ΔP| of the differential pressure value ΔP as the abnormality determination evaluation value is larger than the determination reference value ΔP0, the processor 2a of the controller 202 determines that there is an abnormality in either one of the left travel device 50 and the right travel device 60. Where the swing angle ψ is not within the predetermined swing angle range or where the absolute value |φ| of the roll angle φ of the upper swing structure 102 is larger than the predetermined angle φt, the processor 2a of the controller 202 does not determine that there is an abnormality in either one of the left travel device 50 and the right travel device 60.

[0205] According to this configuration, since the abnormality determination of the travel devices 50 and 60 can be made by regarding the roll angle φswg of the upper swing structure 102 as the roll angle φtrv of the lower track structure 101, it is not necessary to execute the calculation processing of the track structure roll angle φtrv based on the inclination angles (φswg and θswg) of the upper swing structure 102 and the swing angle ψswg described in the third embodiment. Therefore, it is possible to appropriately make the abnormality determination of the travel devices 50 and 60 while reducing the calculation load.<Modified example 3>

[0206] In the first embodiment, the inclination calculation section 378 may compute the track structure roll angle φ on the basis of the swing structure roll angle φswg, the swing structure pitch angle θswg, and the swing angle ψ as described in the third embodiment.

[0207] In a modified example 3, the inclination angle sensing device (inclination state sensor) 376 includes the swing structure inclination angle sensor 376a that is attached to the upper swing structure 102 to sense the inclination angles (the roll angle φswg and the pitch angle θswg) of the upper swing structure 102 with respect to the horizontal plane, the swing angle sensor 376b that senses the swing angle ψ of the upper swing structure 102 with respect to the lower track structure 101, and the inclination calculation section (computation device) 378 that computes the roll angle φtrv, which is an inclination angle in the lateral direction of the lower track structure 101 with respect to the horizontal plane, on the basis of the inclination angles (the roll angle φswg and the pitch angle θswg) of the upper swing structure 102 sensed by the swing structure inclination angle sensor 376a and the swing angle ψ of the upper swing structure 102 sensed by the swing angle sensor 376b. The processor 2a of the controller 2 computes the correction amount Pc on the basis of the roll angle φtrv of the lower track structure 101.

[0208] According to this configuration, in addition to the action and effect similar to those in the first embodiment, it is possible to simplify the configuration of the hydraulic excavator 100 and reduce the manufacturing cost by omitting the installation of the inclination angle sensor in the lower track structure 101.<Modified example 4>

[0209] In the above embodiments, an examples in which the differential pressure value (the second embodiment and the third embodiment) and the corrected differential pressure value (the first embodiment and the fourth embodiment) are employed as the abnormality determination evaluation values has been described, but the present invention is not limited thereto. The integrated value of the differential pressure values and the integrated value of the corrected differential pressure values may be employed as the abnormality determination evaluation values. For example, in the second embodiment, after the processing of Step S2 in Fig. 15, the controller 202 adds a plurality of differential pressure values calculated in the past Step S2 to the differential pressure value calculated in Step S2 to compute the integrated value of a certain number (for example, N pieces) of differential pressure values. In Step S250, the controller 202 extracts the integrated value of the differential pressure values as the abnormality determination evaluation value. It should be noted that a value (ΔP0 × N) obtained by multiplying the determination reference value described in the second embodiment by a certain number (for example, N pieces) is set to a determination reference value ΔP0' to be compared with the integrated value of the differential pressure values (ΔP0' = ΔP0 × N). The upper limit value Pu corresponds to ΔP0' (Pu = ΔP0') and the lower limit value Pl corresponds to -ΔP0' (Pl = -ΔP0').

[0210] By using the differential pressure integrated value as the abnormality determination evaluation value, the influence of the road surface conditions can be eliminated and an abnormality of the left and right travel devices 50 and 60 can be appropriately sensed.<Modified example 5>

[0211] The low-pass filter processing may be performed on the first pump pressure P1 sensed by the first pressure sensor 13 and the second pump pressure P2 sensed by the second pressure sensor 23, and the abnormality determination evaluation value may be calculated on the basis of the differential pressure value between the first pump pressure P1 and the second pump pressure P2 after the low-pass filter processing. The low-pass filter processing removes pressure fluctuations in the first pump pressure P1 and the second pump pressure P2 that occur when the left and right travel devices 50 and 60 accelerate, and moving average processing is cited as an example.

[0212] When the controller performs the low-pass filter processing on the respective pressure values from the first pressure sensor 13 and the second pressure sensor 23, the transitional fluctuation components included in the respective pressure values are removed, and thus the abnormality determination accuracy of the left and right travel devices 50 and 60 can be maintained in an unsteady travelling state such as a state during acceleration.<Modified example 6>

[0213] Although an example in which the work machine is the hydraulic excavator 100 has been described in the above embodiments, the present invention is not limited thereto. The present invention is applicable to various work machines provided with the hydraulically-driven or electrically-driven left travel device 50 and right travel device 60.

[0214] Although the embodiments of the present invention have been described above, the above-described embodiments merely depict some application examples of the present invention, and it is not intended to limit the technical scope of the present invention to the specific configurations of the above-described embodiments.Description of Reference Characters

[0215] 1: engine 2: controller 2a: processor (first processor) 2b: non-volatile memory (memory) 3: work operation sensor 4: swing operation sensor 5: travelling operation sensor 6: travelling lever device (travelling operation device) 11: first hydraulic pump 13: first pressure sensor (travelling state sensor) 21: second hydraulic pump 23: second pressure sensor (travelling state sensor) 31: left travelling motor (hydraulic motor, hydraulic actuator) 32: right travelling motor (hydraulic motor, hydraulic actuator) 33: boom cylinder (hydraulic actuator) 34: arm cylinder (hydraulic actuator) 35: bucket cylinder (hydraulic actuator) 36: swing motor (hydraulic actuator) 37: actuator for attachment (hydraulic actuator) 50: left travel device 51: travel drive system 60: right travel device 61: travel drive system 70: state determination section 76: inclination angle sensor (inclination state sensor) 80: diagnostic device 81: differential pressure value calculation section 82: effective differential pressure value extraction section 83: correction amount calculation section 90: abnormality determination section 91: display device (output device) 92: communication device (output device, transmitter) 100: hydraulic excavator (work machine) 101: lower track structure 102: upper swing structure 103: work device 107: machine body 110: operation room 200: hydraulic drive system 202: controller 277: inclination state determination section 281: differential pressure value calculation section 282: effective differential pressure value extraction section 290: abnormality determination section 302: controller 376: inclination angle sensing device 376a: swing structure inclination angle sensor (inclination state sensor, inclination angle sensor) 376b: swing angle sensor 377: inclination state determination section 378: inclination calculation section (computation device) 400: hydraulic excavator 402: controller 402a: processor (second processor) 410: diagnostic system 440: server 440a: processor (first processor) 440b: non-volatile memory (memory) 461: input device 462: display device (output device) 480: diagnostic device 481: feature amount correction section 482: feature amount computation section 483: correction amount calculation section 490: analysis section 491: display device (output device) 492: sound output device (output device) 495: travelling state amount calculation section 496: inclination state amount calculation section 498: communication device (output device, receiver) FL, FR: load G: centroid position P1: first pump pressure P2: second pump pressure Pc: correction amount Pc1: first correction amount Pc2: second correction amount Pl: lower limit value (negative determination reference value) Pu: upper limit value (positive determination reference value) ΔP: differential pressure value (abnormality determination evaluation value) ΔP0: determination reference value ΔPc: corrected differential pressure value (abnormality determination evaluation value) θ, θtrv: track structure pitch angle θswg: swing structure pitch angle φ, φtrv: track structure roll angle φswg: swing structure roll angle ψ: swing angle φt: allowable roll angle (predetermined angle) ψ: swing angle

Examples

first embodiment

[0010]Fig. 1 is a side view of a hydraulic excavator 100 according to the present invention.

[0011]As depicted in Fig. 1, the hydraulic excavator 100 is provided with a lower track structure 101, an upper swing structure 102 swingably provided with respect to the lower track structure 101, and a work device 103 attached to the front side of the upper swing structure 102. The lower track structure 101 and the upper swing structure 102 configure a machine body 107 of the hydraulic excavator 100.

[0012]The work device 103 is provided with a boom 104 attached to a right front portion of the upper swing structure 102 so as to be rotatable in the vertical direction, an arm 105 attached to a tip end portion of the boom 104 so as to be rotatable in the vertical and longitudinal directions, a bucket 106 attached to a tip end portion of the arm 105 so as to be rotatable in the vertical and longitudinal directions, a boom cylinder 33 as a hydraulic actuator for driving the boom 104, an arm cylin...

second embodiment

[0132]As described above, in the second embodiment, when the absolute value of the roll angle φ (the magnitude of the roll angle φ) of the lower track structure 101 is larger than the predetermined angle φt, the abnormality determination processing is not executed because the abnormality determination processing is affected. The predetermined angle φt is a threshold value of the roll angle φ for determining whether or not the inclination state affects the abnormality determination processing of the travel devices 50 and 60. The predetermined angle φt corresponds to the roll angle φ of, for example, ±10% (in the present embodiment, -10%) with respect to the balanced load when there is no inclination (φ = 0°). Therefore, the abnormality determination processing is executed only in a case where the change in the load due to inclination is within ±10%.

[0133]According to the second embodiment described above, the following action and effect are exhibited.

[0134]The processor 2a of the con...

third embodiment

[0149]Fig. 19 is a diagram similar to that of Fig. 15 and is a flowchart for depicting an example of the flow of abnormality determination processing executed by the controller 302 according to the In the flowchart of Fig. 19, processing of Step S307 is added between Step S2 and Step S10 of the flowchart of Fig. 15.

[0150]As depicted in Fig. 19, when the differential pressure calculation processing (Step S2) is terminated, the processing proceeds to Step S307. In Step S307, the inclination state determination section 377 acquires the track structure roll angle φ calculated by the inclination calculation section 378. It should be noted that the inclination calculation section 378 acquires the swing structure roll angle φswg, the swing structure pitch angle θswg, and the swing angle ψ sensed by the inclination angle sensing device 376 at a predetermined computation cycle, calculates the track structure roll angle φtrv, and outputs it to the controller 302.

[0151]According to the third ...

Claims

1. A diagnostic device comprising: a first processor for diagnosing an abnormality of a travel device on a basis of a travelling feature amount representing a travelling state of the travel device mounted to a machine body of a work machine; and an output device for outputting a result of a diagnosis performed by the first processor, wherein the first processor is configured to acquire an inclination feature amount representing an inclination state of the machine body, compute a correction amount for canceling an influence of the inclination state of the machine body on the travelling feature amount of the travel device on a basis of the inclination feature amount, compute a corrected travelling feature amount by correcting the travelling feature amount on a basis of the correction amount, compute an abnormality determination evaluation value on a basis of the corrected travelling feature amount, determine whether or not there is an abnormality in the travel device on a basis of the abnormality determination evaluation value, and output, when it is determined that there is an abnormality, relevant determination result to the output device.

2. A work machine provided with the diagnostic device according to claim 1, wherein the work machine includes: the machine body; a work device that is attached to the machine body; a first hydraulic pump and a second hydraulic pump that are provided in the machine body; a travelling operation device that issues an instruction of an operation of the travel device; a left travel device that is the travel device having a left travelling motor driven by hydraulic fluid supplied from the first hydraulic pump; a right travel device that is the travel device having a right travelling motor driven by hydraulic fluid supplied from the second hydraulic pump; the first processor that controls capacities of the first hydraulic pump and the second hydraulic pump according to an operation of the travelling operation device; a first pressure sensor that senses a first pump pressure that is a delivery pressure of the first hydraulic pump; a second pressure sensor that senses a second pump pressure that is a delivery pressure of the second hydraulic pump; and an inclination state sensor that senses an inclination state of the machine body with respect to a horizontal plane, and the first processor is configured to compute a differential pressure value between the first pump pressure and the second pump pressure as the travelling feature amount, compute a roll angle that is an inclination angle in a lateral direction of the machine body as the inclination feature amount on a basis of a sensor value representing the inclination state sensed by the inclination state sensor, compute a correction amount for canceling an influence of the inclination state of the machine body on the first pump pressure and the second pump pressure on a basis of the roll angle of the machine body, compute a corrected differential pressure value as the corrected travelling feature amount by correcting the differential pressure value on a basis of the correction amount, compute the abnormality determination evaluation value on a basis of the corrected differential pressure value, determine whether or not there is an abnormality in either one of the left travel device and the right travel device on a basis of the abnormality determination evaluation value, and output, when it is determined that there is an abnormality, relevant determination result to the output device.

3. The work machine according to claim 2, wherein the first processor is configured to compute, as the correction amount, a variation in the differential pressure value caused by an increase in a load acting on one of the left travel device and the right travel device and a decrease in a load acting on other one of the left travel device and the right travel device, the increase and the decrease being due to an inclination of the machine body in the lateral direction.

4. The work machine according to claim 2, wherein the first processor is configured to determine that there is an abnormality in either one of the left travel device and the right travel device when the roll angle is equal to or smaller than a predetermined angle and the abnormality determination evaluation value is larger than a determination reference value.

5. The work machine according to claim 2, wherein the machine body has: a lower track structure that is provided with the left travel device and the right travel device; and an upper swing structure that is swingably provided with respect to the lower track structure, the inclination state sensor includes: a swing structure inclination angle sensor that is attached to the upper swing structure and senses an inclination angle of the upper swing structure with respect to the horizontal plane; a swing angle sensor that senses a swing angle of the upper swing structure with respect to the lower track structure; and a computation device that is configured to compute a roll angle that is an inclination angle of the lower track structure in the lateral direction with respect to the horizontal plane, on a basis of the inclination angle of the upper swing structure sensed by the swing structure inclination angle sensor and the swing angle of the upper swing structure sensed by the swing angle sensor, and the first processor is configured to compute the correction amount on the basis of the roll angle of the lower track structure.

6. A diagnostic system including the diagnostic device and the work machine according to claim 1, wherein the diagnostic device is provided with: a receiver that receives the travelling feature amount and the inclination feature amount transmitted from the work machine; and a server that has the first processor for diagnosing an abnormality of the travel device of the work machine on a basis of the travelling feature amount and the inclination feature amount received by the receiver, and a memory for storing a correction amount parameter used for computing the correction amount, the work machine is provided with: a travelling state sensor that senses a travelling state of the travel device; an inclination state sensor that senses an inclination state of the machine body; a second processor that is configured to compute the travelling feature amount on a basis of a sensor value representing the travelling state sensed by the travelling state sensor, and compute the inclination feature amount on a basis of a sensor value representing the inclination state sensed by the inclination state sensor; and a transmitter that transmits the travelling feature amount and the inclination feature amount computed by the second processor to the server, the second processor is configured to compute the travelling feature amount and the inclination feature amount in synchronization with each other, and the first processor is configured to compute the correction amount on a basis of the correction amount parameter stored in the memory and the inclination feature amount.

7. The diagnostic system according to claim 6, wherein the second processor of the work machine is configured to compute the travelling feature amount and the inclination feature amount for each of a plurality of cycles, and the first processor of the server is configured to be capable of computing the abnormality determination evaluation value for each of the plurality of cycles on the basis of the travelling feature amount and the inclination feature amount for each of the plurality of cycles.

8. A work machine comprising: a machine body; a work device that is attached to the machine body; a first hydraulic pump and a second hydraulic pump that are provided in the machine body; a left travel device that has a left travelling motor driven by hydraulic fluid supplied from the first hydraulic pump; a right travel device that has a right travelling motor driven by hydraulic fluid supplied from the second hydraulic pump; a travelling operation device that issues instructions of operations of the left travel device and the right travel device; a processor that controls capacities of the first hydraulic pump and the second hydraulic pump according to an operation of the travelling operation device; a first pressure sensor that senses a first pump pressure that is a delivery pressure of the first hydraulic pump; a second pressure sensor that senses a second pump pressure that is a delivery pressure of the second hydraulic pump; an inclination angle sensing device that senses an inclination angle of the machine body with respect to a horizontal plane; and an output device that outputs a computation result of the processor, wherein the processor is configured to compute an abnormality determination evaluation value on a basis of a differential pressure value between the first pump pressure and the second pump pressure, determine that there is an abnormality in either one of the left travel device and the right travel device when the inclination angle of the machine body sensed by the inclination angle sensing device is equal to or smaller than a predetermined angle and the abnormality determination evaluation value is larger than a determination reference value, and output, when it is determined that there is an abnormality, relevant determination result to the output device.

9. The work machine according to claim 8, wherein the machine body has: a lower track structure that is provided with the left travel device and the right travel device; and an upper swing structure that is swingably provided with respect to the lower track structure, the inclination angle sensing device includes: a swing structure inclination angle sensor that is attached to the upper swing structure and senses an inclination angle of the upper swing structure with respect to the horizontal plane; a swing angle sensor that senses a swing angle of the upper swing structure with respect to the lower track structure; and a computation device that is configured to compute a roll angle that is an inclination angle of the lower track structure in a lateral direction with respect to the horizontal plane on a basis of the inclination angle of the upper swing structure sensed by the swing structure inclination angle sensor and the swing angle of the upper swing structure sensed by the swing angle sensor, and the processor is configured to determine that there is an abnormality in either one of the left travel device and the right travel device when the roll angle of the lower track structure is equal to or smaller than the predetermined angle and the abnormality determination evaluation value is larger than the determination reference value.

10. The work machine according to claim 8, wherein the machine body has: a lower track structure that is provided with the left travel device and the right travel device; an upper swing structure that is swingably provided with respect to the lower track structure; and a swing angle sensor that senses a swing angle of the upper swing structure with respect to the lower track structure, the inclination angle sensing device is a swing structure inclination angle sensor that is attached to the upper swing structure and senses an inclination angle of the upper swing structure with respect to the horizontal plane, and the processor is configured to determine whether or not the swing angle sensed by the swing angle sensor is within a predetermined swing angle range including a swing angle at which a direction of the lower track structure and a direction of the upper swing structure coincide with each other, and determine that there is an abnormality in either one of the left travel device and the right travel device when the swing angle is within the predetermined swing angle range, the inclination angle of the upper swing structure sensed by the swing structure inclination angle sensor is equal to or smaller than the predetermined angle, and the abnormality determination evaluation value is larger than the determination reference value.

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