Diagnosis system of construction machine, and diagnosis method of construction machine

Abstract

To efficiently and accurately calculate a natural descent amount of work implements and utilize a calculated amount for repair and maintenance.SOLUTION: A diagnosis system of a work machine comprises: a detection data acquisition unit that acquires detection data of the angle of work implements included in a work machine; and a calculation unit that calculates a natural descent amount of a tip portion of the work implements at the time when a work lever operated for operation of the work implements is in a neutral state on the basis of the angle detection data and dimension data of the work implements.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a diagnostic system for a work machine and a diagnostic method for a work machine. [Background technology]

[0002] BACKGROUND ART In the technical field related to work machines, a work machine having a work implement, such as that disclosed in Patent Document 1, is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-204193 Summary of the Invention [Problem to be solved by the invention]

[0004] The working implement of a work machine may naturally drop. Causes of natural drop include the weight of the work implement itself, the weight of the excavated material held by the work implement, leakage of hydraulic oil from the hydraulic cylinder that operates the work implement, and leakage of hydraulic oil from the control valve that controls the hydraulic oil supplied to the hydraulic cylinder. When the work implement naturally drops, the work efficiency of the work machine may decrease. Therefore, it is necessary to measure the amount of natural drop of the work implement and perform maintenance on the work implement as necessary. If the work machine is stopped from operating to measure the amount of natural drop of the work implement, the availability rate of the work machine will decrease.

[0005] The present disclosure aims to efficiently and accurately calculate the amount of natural descent of a work machine and use the calculated amount for repair and maintenance. [Means for solving the problem]

[0006] According to the present disclosure, there is provided a diagnostic system for a work machine, comprising: a detection data acquisition unit that acquires detection data of the angle of a work implement possessed by the work machine; and a calculation unit that calculates the amount of natural descent of the tip of the work implement when a work lever operated to operate the work implement is in a neutral state, based on the angle detection data and dimensional data of the work implement. [Effects of the Invention]

[0007] According to the present disclosure, the amount of natural descent of a work machine can be calculated efficiently and accurately, and the calculation can be utilized for repair and maintenance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram that schematically shows a management system for a work machine according to a first embodiment. [Figure 2] FIG. 2 is a diagram schematically showing the work machine according to the first embodiment. [Figure 3] FIG. 3 is a diagram showing a hydraulic system of the work machine according to the first embodiment. [Figure 4] FIG. 4 is a diagram schematically showing the operation device of the work machine according to the first embodiment. [Figure 5] FIG. 5 is a hardware configuration diagram showing the controller of the work machine according to the first embodiment. [Figure 6] FIG. 6 is a functional block diagram showing the diagnostic system for a work machine according to the first embodiment. [Figure 7] FIG. 7 is a diagram illustrating the amount of natural descent of the work implement according to the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating a method for evaluating a work machine by the evaluation unit according to the first embodiment. [Figure 9] FIG. 9 is a diagram illustrating a method for evaluating a work machine by the evaluation unit according to the first embodiment. [Figure 10] FIG. 10 is a diagram illustrating a method for evaluating a work machine by the evaluation unit according to the first embodiment. [Figure 11]FIG. 11 is a flowchart showing the diagnostic method for a work machine according to the first embodiment. [Figure 12] FIG. 12 is a flowchart showing the diagnostic method for a work machine according to the first embodiment. [Figure 13] FIG. 13 is a diagram illustrating a method for evaluating a work machine by an evaluation unit according to the second embodiment. [Figure 14] FIG. 14 is a diagram illustrating a method for evaluating a work machine by an evaluation unit according to the second embodiment. [Figure 15] FIG. 15 is a diagram illustrating a method for evaluating a work machine by an evaluation unit according to the second embodiment. [Figure 16] FIG. 16 is a diagram schematically showing a work machine according to a third embodiment. [Figure 17] FIG. 17 is a diagram schematically showing a work machine according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the embodiments. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0010] [First embodiment] A first embodiment will be described.

[0011] <Management system> FIG. 1 is a diagram schematically showing a management system 1 for a work machine 2 according to this embodiment. The management system 1 manages a work machine 2 operating at a work site 101. In this embodiment, the work machine 2 is a hydraulic excavator. The management system 1 has a management server 3. The management server 3 includes a computer system. The management server 3 is located outside the work machine 2. The management server 3 is located in a control room 100 located in a remote location from the work site 101. The management server 3 manages the work machine 2. The work machine 2 has a controller 50. The management server 3 can communicate with the controller 50 of the work machine 2 via a communication system 4. The management server 3 collects operation data of the work machine 2. The management server 3 outputs control commands to the work machine 2.

[0012] The communication system 4 includes a mobile phone communication network. The communication system 4 may also include a satellite communication network. The communication system 4 may also include a public communication line or a specific communication line. The communication system 4 may also include the Internet or a local area network.

[0013] <Work machinery> 2 is a diagram schematically showing a work machine 2 according to this embodiment. As shown in FIGS. 1 and 2, the work machine 2 has a running body 5, a rotating body 6 supported by the running body 5, and a work implement 7 supported by the rotating body 6.

[0014] The running body 5 runs on the work site 101 while supporting the rotating body 6. The running body 5 has a pair of tracks 5A. The work machine 2 runs as the tracks 5A rotate. The rotating body 6 is capable of rotating while being supported by the running body 5.

[0015] The rotating unit 6 is the body of the work machine 2. The rotating unit 6 is disposed higher than the running unit 5. The rotating unit 6 is supported by the running unit 5 so as to be rotatable about a rotation axis RX. The rotation axis RX extends in the up-down direction of the rotating unit 6. The rotating unit 6 has a cab. The operator of the work machine 2 sits in the cab.

[0016] The work implement 7 is supported by the revolving unit 6. The work implement 7 has a boom 8, an arm 9, a bucket 10, a boom cylinder 11, an arm cylinder 12, and a bucket cylinder 13. The boom 8 is rotatably connected to the front of the revolving unit 6. The arm 9 is rotatably connected to the tip of the boom 8. The bucket 10 is rotatably connected to the tip of the arm 9. The bucket 10 has a cutting edge 10A.

[0017] The base end of the boom 8 is connected to the rotating bed 6 via a boom pin 14. The base end of the arm 9 is connected to the tip of the boom 8 via an arm pin 15. The bucket 10 is connected to the tip of the arm 9 via a bucket pin 16. The boom 8 is rotatable around the boom pin 14. The arm 9 is rotatable around the arm pin 15. The bucket 10 is rotatable around the bucket pin 16.

[0018] The rotation axis AX1 of the boom 8 passes through the boom pin 14. The rotation axis AX2 of the arm 9 passes through the arm pin 15. The rotation axis AX3 of the bucket 10 passes through the bucket pin 16. The rotation axis AX1 of the boom 8, the rotation axis AX2 of the arm 9, and the rotation axis AX3 of the bucket 10 each extend in the left-right direction of the rotating structure 6. The rotation axes AX1, AX2, and AX3 are parallel to each other. The boom 8, the arm 9, and the bucket 10 each move along a motion plane perpendicular to the rotation axis AX1.

[0019] The boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13 are hydraulic cylinders driven by hydraulic oil. The boom cylinder 11 operates the boom 8. The arm cylinder 12 operates the arm 9. The bucket cylinder 13 operates the bucket 10.

[0020] The bucket cylinder 13 is attached to the arm 9. The bucket 10 rotates relative to the arm 9 as the bucket cylinder 13 extends and retracts. The work implement 7 has a bucket link. The bucket link connects the bucket cylinder 13 and the bucket 10. The bucket link has a first link member 17 and a second link member 18. The tip end of the first link member 17 and the tip end of the second link member 18 are connected via a bucket cylinder top pin 19 so as to be able to rotate relative to each other. The first link member 17 and the second link member 18 are connected to the tip end of the bucket cylinder 13 by the bucket cylinder top pin 19.

[0021] The base end of the first link member 17 is rotatably connected to the arm 9 by a first link pin 20. The base end of the second link member 18 is rotatably connected to the bracket of the bucket 10 by a second link pin 21.

[0022] The angle of the boom 8 relative to the revolving unit 6 is defined as a boom angle θ1. The boom angle θ1 is the angle between a line passing through the boom pin 14 and the arm pin 15 and a line parallel to the revolving axis RX on the operating plane.

[0023] The angle of the arm 9 relative to the boom 8 is defined as the arm angle θ2. The arm angle θ2 is the angle between a line passing through the boom pin 14 and the arm pin 15 and a line passing through the arm pin 15 and the bucket pin 16 on the operating plane.

[0024] The angle of the bucket 10 relative to the arm 9 is defined as the bucket angle θ3. The bucket angle θ3 is the angle between a line passing through the arm pin 15 and the bucket pin 16 and a line passing through the bucket pin 16 and the cutting edge 10A on the operating plane.

[0025] The length of the boom 8 is defined as a boom length L1. The boom length L1 is the distance between the boom pin 14 and the arm pin 15 on the operating plane.

[0026] The length of the arm 9 is defined as an arm length L2, which is the distance between the arm pin 15 and the bucket pin 16 on the operating plane.

[0027] The length of the bucket 10 is defined as a bucket length L3. The bucket length L3 is the distance between the bucket pin 16 and the cutting edge 10A on the operating plane.

[0028] As shown in Fig. 2, the work machine 2 has an angle sensor 22. The angle sensor 22 detects the angle of the work implement 7. The angle sensor 22 includes a boom angle sensor 221 that detects the angle of the boom 8 relative to the rotating bed 6, an arm angle sensor 222 that detects the angle of the arm 9 relative to the boom 8, and a bucket angle sensor 223 that detects the angle of the bucket 10 relative to the arm 9. In this embodiment, the angle sensor 22 is a potentiometer that detects the angles of the boom 8, the arm 9, and the bucket 10.

[0029] The angle sensor 22 may be a stroke sensor that detects the stroke of each of the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13. The angle sensor 22 may be an inertial measurement unit (IMU) attached to each of the boom 8, the arm 9, and the bucket 10. The IMU can detect the attitude of each of the boom 8, the arm 9, and the bucket 10.

[0030] <Hydraulic system> Fig. 3 is a diagram showing the hydraulic system 23 of the work machine 2 according to this embodiment. As shown in Fig. 3, the hydraulic system 23 has an engine 24, a hydraulic pump 25, a boom control valve 26, an arm control valve 27, a bucket control valve 28, a tank 29, a boom cylinder 11, an arm cylinder 12, and a bucket cylinder 13.

[0031] The engine 24 is a power source for the work machine 2. An example of the engine 24 is a diesel engine. The hydraulic pump 25 discharges hydraulic oil. The hydraulic pump 25 is driven by power generated by the engine 24. In this embodiment, the hydraulic pump 25 is a variable displacement hydraulic pump. The hydraulic pump 25 has a swash plate 25A that is driven to change the displacement of the hydraulic pump 25.

[0032] The spool of boom control valve 26 moves to a bottom chamber supply position that passes hydraulic oil supplied to bottom chamber 11A of boom cylinder 11, a rod chamber supply position that passes hydraulic oil supplied to rod chamber 11B of boom cylinder 11, and a neutral position that does not pass hydraulic oil. In the example shown in Fig. 3, the spool of boom control valve 26 is disposed in the neutral position.

[0033] The spool of the arm control valve 27 moves to a bottom chamber supply position that passes hydraulic oil supplied to the bottom chamber 12A of the arm cylinder 12, a rod chamber supply position that passes hydraulic oil supplied to the rod chamber 12B of the arm cylinder 12, and a neutral position that does not pass hydraulic oil. In the example shown in Fig. 3, the spool of the arm control valve 27 is arranged in the neutral position.

[0034] The spool of the bucket control valve 28 moves to a bottom chamber supply position that passes hydraulic oil supplied to the bottom chamber 13A of the bucket cylinder 13, a rod chamber supply position that passes hydraulic oil supplied to the rod chamber 13B of the bucket cylinder 13, and a neutral position that does not pass hydraulic oil. In the example shown in Fig. 3, the spool of the bucket control valve 28 is disposed in the neutral position.

[0035] The hydraulic oil supplied from the boom cylinder 11 to the boom control valve 26 is discharged into the tank 29. The hydraulic oil supplied from the arm cylinder 12 to the arm control valve 27 is discharged into the tank 29. The hydraulic oil supplied from the bucket cylinder 13 to the bucket control valve 28 is discharged into the tank 29.

[0036] The hydraulic pump 25, the boom control valve 26, the arm control valve 27, and the bucket control valve 28 are connected via a neutral flow path 43. The neutral flow path 43 is connected to the tank 29 via a negative control mechanism 44 that negatively controls the displacement of the hydraulic pump 25. When the spool of the boom control valve 26, the spool of the arm control valve 27, and the spool of the bucket control valve 28 are each positioned in the neutral position, the hydraulic oil discharged from the hydraulic pump 25 is discharged into the tank 29 via the boom control valve 26, the arm control valve 27, the bucket control valve 28, and the neutral flow path 43. Note that although multiple tanks 29 are shown in FIG. 3, only one tank 29 may be used.

[0037] <Operating device> FIG. 4 is a diagram schematically showing an operating device 48 of the work machine 2 according to this embodiment. The work machine 2 has the operating device 48. The operating device 48 is operated to operate the work machine 2. The operating device 48 is arranged in the cab of the rotating unit 6. An operator in the cab operates the work machine 2 by operating the operating device 48. The operator in the cab can operate the traveling unit 5 to travel, the rotating unit 6 to swing, and the work implement 7 to perform work operations by operating the operating device 48. Work operations of the work implement 7 include operation of the boom 8, operation of the arm 9, and operation of the bucket 10. The operating device 48 includes a pair of operating levers 49 that are operated to perform the swing operation of the rotating unit 6 and the work operation of the work implement 7, and a pair of travel levers (not shown) that are operated to perform the travel operation of the traveling unit 5. FIG. 4 schematically shows the pair of operating levers 49. The operating levers 49 include a left operating lever 49L and a right operating lever 49R.

[0038] The working lever 49 is operated to operate the work implement 7. The working lever 49 is operated to any one of the left, right, forward, and backward from a neutral state. The working lever 49 being in a neutral state includes a state in which the working lever 49 is positioned in the center of the movable range of the working lever 49. The working lever 49 is operated to any one of the left, right, forward, and backward from a neutral state.

[0039] When the left working lever 49L is operated leftward from the neutral position, the arm cylinder 12 is retracted and the arm 9 performs a dumping operation. When the left working lever 49L is operated rightward from the neutral position, the arm cylinder 12 is extended and the arm 9 performs an excavation operation. When the left working lever 49L is operated forward from the neutral position, the rotating body 6 rotates to the right. When the left working lever 49L is operated backward from the neutral position, the rotating body 6 rotates to the left.

[0040] When the right working lever 49R is operated leftward from the neutral position, the bucket cylinder 13 extends, causing the bucket 10 to perform an excavation operation. When the right working lever 49R is operated rightward from the neutral position, the bucket cylinder 13 retracts, causing the bucket 10 to perform a dump operation. When the right working lever 49R is operated forward from the neutral position, the boom cylinder 11 retracts, causing the boom 8 to perform a lowering operation. When the right working lever 49R is operated rearward from the neutral position, the boom cylinder 11 extends, causing the boom 8 to perform a raising operation.

[0041] The working lever 49 being in the neutral state includes the spool of the boom control valve 26, the spool of the arm control valve 27, and the spool of the bucket control valve 28 being disposed in their neutral positions. When the left working lever 49L is in the neutral state, the spool of the arm control valve 27 is disposed in its neutral position. When the right working lever 49R is in the neutral state, the spool of the boom control valve 26 and the spool of the bucket control valve 28 are disposed in their neutral positions.

[0042] <controller> FIG. 5 is a hardware configuration diagram showing a controller 50 of a work machine 2 according to this embodiment. The controller 50 includes a computer system. The controller 50 has a processor 51 such as a CPU (Central Processing Unit), a main memory 52 including non-volatile memory such as ROM (Read Only Memory) and volatile memory such as RAM (Random Access Memory), a storage 53, and an interface 54 including an input / output circuit. The functions of the controller 50 are stored in the storage 53 as a computer program. The processor 51 reads the computer program from the storage 53, loads it into the main memory 52, and executes processing in accordance with the computer program. The computer program may be distributed to the controller 50 via a network.

[0043] The management server 3 also includes a computer system. The management server 3 has a processor, a main memory, a storage, and an interface.

[0044] <Diagnostic system> FIG. 6 is a functional block diagram showing a diagnostic system 60 for a work machine 2 according to this embodiment. The diagnostic system 60 diagnoses the work implement 7 of the work machine 2. The diagnostic system 60 diagnoses the free descent of the work implement 7. The diagnostic system 60 diagnoses the work implement 7 when the work machine 2 is operating at a work site 101. The diagnostic system 60 diagnoses the work implement 7 in parallel with the operation of the work machine 2. The diagnostic system 60 has a management server 3, an angle sensor 22, an operating lever 49, an on-board monitor 57, and a controller 50.

[0045] The controller 50 has a work machine data storage unit 61, a detection data acquisition unit 62, an operation data acquisition unit 63, a neutral state determination unit 64, and a calculation unit 65. The management server 3 has a recording unit 66, an evaluation unit 67, and an input / output unit 68.

[0046] An input device 55 and a display device 56 are connected to the management server 3. When the input device 55 is operated by an administrator in the management room 100, input data is generated. Examples of the input device 55 include a touch panel, a computer keyboard, or input buttons. The display device 56 outputs display data and provides it to the administrator. Examples of the display device 56 include a flat panel display such as a liquid crystal display or an organic EL display. Examples of the input data include a threshold value, which will be described later.

[0047] The controller 50 is connected to the angle sensor 22, the working lever 49, and an on-board monitor 57. The on-board monitor 57 is arranged in the cab of the work machine 2. The on-board monitor 57 includes an input device 58 and a display device 59. When the input device 58 is operated by the operator of the work machine 2, input data is generated. Examples of the input device 58 include a touch panel, a computer keyboard, or input buttons. The display device 59 outputs display data and provides it to the operator. Examples of the display device 59 include a flat panel display such as a liquid crystal display or an organic EL display. Examples of the input data include threshold values, which will be described later.

[0048] The work implement data storage unit 61 stores dimensional data of the work implement 7. The dimensional data of the work implement 7 includes a boom length L1 indicating the length of the boom 8, an arm length L2 indicating the length of the arm 9, and a bucket length L3 indicating the length of the bucket 10. The dimensional data of the work implement 7 is known data that can be derived from the design data or specification data of the work machine 2. The dimensional data including the boom length L1, arm length L2, and bucket length L3 is stored in advance in the work implement data storage unit 61.

[0049] The detection data acquisition unit 62 acquires detection data of the angle of the work implement 7 of the work machine 2. The angle of the work implement 7 is detected by the angle sensor 22. The detection data acquisition unit 62 acquires, from the angle sensor 22, detection data of the angle of the work implement 7 detected by the angle sensor 22. The detection data of the angle of the work implement 7 includes boom angle data indicating boom angle θ1, which is the angle of the boom 8 relative to the revolving structure 6, arm angle data indicating arm angle θ2, which is the angle of the arm 9 relative to the boom 8, and bucket angle data indicating bucket angle θ3, which is the angle of the bucket 10 relative to the arm 9. The boom angle θ1 is detected by the boom angle sensor 221, and the arm angle θ2 is detected by the arm angle sensor 222. The bucket angle θ3 is detected by the bucket angle sensor 223.

[0050] The operation data acquisition unit 63 acquires operation data of the working lever 49. The working lever 49 generates operation data when operated by the operator. The operation data of the working lever 49 includes operation data of the left working lever 49L and operation data of the right working lever 49R. The operation data of the working lever 49 includes neutral operation data indicating that the working lever 49 is in the neutral state. The operation data of the working lever 49 includes operation amount data indicating the amount of operation of the working lever 49.

[0051] The neutral state determination unit 64 determines whether the working lever 49 is in a neutral state based on operation data of the working lever 49. The neutral state determination unit 64 determines whether the left working lever 49L is in a neutral state based on operation data of the left working lever 49L. The neutral state determination unit 64 determines whether the right working lever 49R is in a neutral state based on operation data of the right working lever 49R. In this embodiment, the neutral state determination unit 64 determines that the working lever 49 is in a neutral state when it determines that both the left working lever 49L and the right working lever 49R are in a neutral state.

[0052] The neutral state determination unit 64 determines the start time T1a and end time T2a of the neutral state of the working lever 49 based on the operation data of the working lever 49. The start time T1a of the neutral state is the time when the working lever 49 changes from a non-neutral state to the neutral state. The end time T2a of the neutral state is the time when the working lever 49 changes from the neutral state to a non-neutral state after the start time of the neutral state. The neutral state determination unit 64 determines the start time T1a and end time T2a of the neutral state of the left working lever 49L based on the operation data of the left working lever 49L. The neutral state determination unit 64 determines the start time T1a and end time T2a of the neutral state of the right working lever 49R based on the operation data of the right working lever 49R.

[0053] The calculation unit 65 calculates the amount of natural descent of the tip of the work implement 7 when the working lever 49 is in the neutral state, based on the detection data of the angle of the work implement 7 and the dimensional data of the work implement 7. The tip of the work implement 7 may be the tip of the arm 9 or the cutting edge 10A of the bucket 10. In this embodiment, the tip of the work implement 7 is the tip of the arm 9. The tip of the arm 9 includes the bucket pin 16.

[0054] The calculation unit 65 can calculate the position of the tip of the work implement 7 based on the detection data of the angle of the work implement 7 and the dimensional data of the work implement 7. In this embodiment, the position of the tip of the work implement 7 is the relative position of the tip of the work implement 7 with respect to a reference position defined for the revolving unit 6. The reference position defined for the revolving unit 6 is the position of the boom pin 14.

[0055] When the tip of the work implement 7 is the tip of the arm 9, the calculation unit 65 can calculate the position of the tip of the arm 9 using the theorem of trigonometric functions based on the boom angle θ1, the arm angle θ2, the boom length L1, and the arm length L2.

[0056] The calculation unit 65 calculates an initial height H1a of the tip of the work implement 7 based on detection data for the angle of the work implement 7 and dimensional data of the work implement 7 at the start time T1a of the neutral state. The calculation unit 65 calculates a final height H2a of the tip of the work implement 7 based on detection data for the angle of the work implement 7 and dimensional data of the work implement 7 at the end time T2a of the neutral state. In this embodiment, the initial height H1a is the initial height of the tip of the arm 9. The final height H2a is the final height of the tip of the arm 9. The calculation unit 65 calculates a natural descent amount ΔHa of the tip of the work implement 7 based on the difference between the initial height H1a and the final height H2a.

[0057] Fig. 7 is a diagram illustrating the amount of natural descent ΔHa of the work implement 7 according to this embodiment. As shown in Fig. 7, when the work machine 2 loads excavated material excavated with the bucket 10 into the dump body of the dump truck 70, the work machine 2 may enter a standby state in which it waits for the dump truck 70 to enter the loading position LP. In this standby state, there is a high possibility that the working lever 49 will be in the neutral state. The neutral state determination unit 64 determines whether the working lever 49 is in the neutral state based on the operation data of the working lever 49.

[0058] As shown in Figure 7, at the start time T1a of the neutral state, the height of the tip of the work implement 7 is an initial height H1a. As the neutral state continues, there is a possibility that the work implement 7 will naturally descend. At the end time T2a of the neutral state, there is a possibility that the height of the tip of the work implement 7 will become a final height H2a, which is lower than the initial height H1a, due to the natural descent of the work implement 7. The calculation unit 65 can calculate the amount of natural descent ΔHa when the work lever 49 is in the neutral state, based on the difference between the initial height H1a and the final height H2a.

[0059] The calculation unit 65 calculates a recorded value R based on a value obtained by dividing the difference between the initial height H1a and the final height H2a by the neutral state duration ΔT during which the operation lever 49 remains in the neutral state. In this embodiment, the calculation unit 65 calculates a recorded value Ra by multiplying the value obtained by dividing the difference between the initial height H1a and the final height H2a by the neutral state duration ΔT during which the operation lever 49 remains in the neutral state by a unit time Ut. The difference between the initial height H1a and the final height H2a is the amount of natural descent ΔHa. The neutral state duration ΔT is the difference between the start time T1a and the end time T2a. The recorded value Ra is calculated based on the following equation (1).

[0060]

number

[0061] As shown in Figure 7, the neutral state of the working lever 49 may occur in a loaded state in which the bucket 10 holds an excavated object. The neutral state of the working lever 49 may occur in an unloaded state in which the bucket 10 does not hold an excavated object. The natural drop amount ΔHa in a loaded state is greater than the natural drop amount ΔHa in an unloaded state. The calculation unit 65 can calculate the natural drop amount ΔHa in a loaded state and the natural drop amount ΔHa in an unloaded state. The calculation unit 65 can calculate the recorded value Ra in a loaded state and the recorded value Ra in an unloaded state.

[0062] The calculation unit 65 transmits the recorded value Ra to the management server 3. The recorded value Ra is calculated every time the working lever 49 is brought into the neutral state. The calculation unit 65 transmits the recorded value Ra to the management server 3 every time it calculates the recorded value Ra. The calculation unit 65 may store a plurality of recorded values Ra and transmit the plurality of recorded values Ra to the management server 3 at a predetermined timing. The calculation unit 65 may also transmit the largest recorded value Ra of the plurality of recorded values Ra stored during a predetermined period to the management server 3.

[0063] The recording unit 66 records the recorded value Ra transmitted from the calculation unit 65. The recording unit 66 functions as a database of the recorded values Ra.

[0064] The evaluation unit 67 determines the state of the work implement 7 based on the recorded value Ra recorded in the recording unit 66. Determining the state of the work implement 7 includes determining the deterioration state of the work implement 7. Determining the deterioration state of the work implement 7 includes evaluating the amount of natural descent ΔHa of the tip of the work implement 7. One cause of the natural descent of the work implement 7 is deterioration of at least a part of the hydraulic system 23. Deterioration of the hydraulic system 23 may cause hydraulic oil to leak from the hydraulic system 23.

[0065] Deterioration of the hydraulic system 23 includes deterioration of at least one of the boom cylinder 11, the arm cylinder 12, the boom control valve 26, and the arm control valve 27. Deterioration of the boom cylinder 11 may cause hydraulic oil to leak from the boom cylinder 11. Deterioration of the arm cylinder 12 may cause hydraulic oil to leak from the arm cylinder 12. Deterioration of the boom control valve 26 may cause hydraulic oil to leak from the boom control valve 26. Deterioration of the arm control valve 27 may cause hydraulic oil to leak from the arm control valve 27. Causes of hydraulic oil leakage from the boom control valve 26 or the arm control valve 27 include increased clearance due to wear in the valve chamber caused by the intrusion of foreign matter, and erosion due to jets or bubble deposition. Hydraulic oil leakage from the hydraulic system 23 may cause the work implement 7 to naturally descend. If the amount of hydraulic oil leakage increases, the amount of natural descent ΔHa may increase.

[0066] 8, 9, and 10 are diagrams illustrating a method for evaluating the work machine 7 by the evaluation unit 67 according to this embodiment. In the graphs shown in Fig. 8, 9, and 10, the horizontal axis represents the operating time t of the work machine 2. The vertical axis represents the recorded value Ra. The line La represents the recorded value Ra calculated based on the amount of natural descent ΔHa.

[0067] 8, when the recorded value Ra exceeds a predetermined first threshold value Th1 (first threshold value), the evaluation unit 67 determines that the amount of natural descent ΔHa of the work implement 7 indicates an abnormal value, and determines that the condition of the work implement 7 is poor. The poor condition of the work implement 7 includes leakage of hydraulic oil from at least one of the boom cylinder 11, the arm cylinder 12, the boom control valve 26, and the arm control valve 27.

[0068] As shown in Fig. 9, an initial value R0 related to the recorded value Ra is calculated. The initial value R0 is the recorded value Ra at the time when the calculation unit 65 calculates the first recorded value Ra. The initial value R0 is the recorded value Ra when the hydraulic system 23 is in a good condition. If the difference ΔR0 between the initial value R0 and the recorded value Ra exceeds a predetermined second threshold, the evaluation unit 67 may determine that the amount of natural descent ΔHa of the work implement 7 indicates an abnormal value, and may determine that the condition of the work implement 7 is poor.

[0069] 10, the evaluation unit 67 calculates the amount of increase ΔRv of the recorded value Ra per unit time t0. That is, the evaluation unit 67 calculates the rate of increase of the recorded value Ra. If the rate of increase of the recorded value Ra exceeds a predetermined third threshold, the evaluation unit 67 may determine that the amount of natural drop ΔHa of the work implement 7 indicates an abnormal value, and may determine that the condition of the work implement 7 is poor.

[0070] The input / output unit 68 receives input data from the input device 55. The input / output unit 68 causes the display device 56 to display the display data. The input / output unit 68 causes the display device 56 to display the amount of natural drop ΔHa or the recorded value Ra calculated by the calculation unit 65. The input / output unit 68 causes the display device 56 to display the evaluation result by the evaluation unit 67. The input / output unit 68 may transmit the evaluation result by the evaluation unit 67 to the controller 50. The evaluation result by the evaluation unit 67 may be displayed on the display device 59 of the work machine 2. The amount of natural drop ΔHa or the recorded value Ra calculated by the calculation unit 65 may be displayed on the display device 59.

[0071] <Diagnostic method> 11 and 12 are flowcharts showing a method for diagnosing a work machine 2 according to this embodiment. Fig. 11 shows the operation of the controller 50. Fig. 12 shows the operation of the management server 3.

[0072] The work machine 2 operates at a work site 101. As shown in Fig. 11, while the work machine 2 is operating, the detection data acquisition unit 62 acquires detection data of the angle of the work implement 7 from the angle sensor 22 (step SA1). While the work machine 2 is operating, the operation data acquisition unit 63 acquires operation data of the work lever 49 from the work lever 49 (step SA2).

[0073] The neutral state determination unit 64 determines whether the neutral state of the working lever 49 has started based on the operation data of the working lever 49 (step SA3). If it is determined in step SA3 that the neutral state of the working lever 49 has not started (step SA3: No), the process returns to step SA1.

[0074] If it is determined in step SA3 that the neutral state of the working lever 49 has started (step SA3: Yes), the calculation unit 65 calculates the height of the tip of the working implement 7 based on the detection data of the angle of the working implement 7 and the dimensional data of the working implement 7 (step SA4). The calculation unit 65 calculates at least the initial height H1a, which is the height of the tip of the working implement 7 at the start time T1a of the neutral state of the working lever 49.

[0075] The neutral state determination unit 64 determines whether the neutral state of the working lever 49 has ended based on the operation data of the working lever 49 (step SA5). If it is determined in step SA5 that the neutral state of the working lever 49 has not ended (step SA5: No), the process returns to step SA4.

[0076] In step SA5, if it is determined that the neutral state of the working lever 49 has ended (step SA5: Yes), the calculation unit 65 calculates the final height H2a, which is the height of the tip of the working implement 7 at least at the end point T2a of the neutral state of the working lever 49.

[0077] The calculation unit 65 calculates the recorded value Ra based on the above-mentioned formula (1) (step SA6), and transmits the recorded value Ra to the management server 3 via the communication system 4 (step SA7).

[0078] As shown in FIG. 12, the recording unit 66 records the recorded value Ra transmitted from the calculation unit 65 to the management server 3 (step SB1).

[0079] The evaluation unit 67 determines the state of the work implement 7 based on the multiple recorded values Ra recorded in the recording unit 66. The evaluation unit 67 evaluates the amount of natural descent ΔHa of the tip of the work implement 7 based on the multiple recorded values Ra recorded in the recording unit 66 (step SB2).

[0080] As explained with reference to Figures 10, 11, and 12, the evaluation unit 67 uses a predetermined threshold value to determine whether the amount of natural descent ΔHa of the tip of the work implement 7 indicates an abnormal value.

[0081] The evaluation unit 67 determines whether the condition of the work implement 7 is poor based on the evaluation of the amount of natural descent ΔHa (step SB3). As described above, the poor condition of the work implement 7 includes leakage of hydraulic oil from at least one of the boom cylinder 11, the arm cylinder 12, the boom control valve 26, and the arm control valve 27.

[0082] If it is determined in step SB3 that the condition of the work implement 7 is poor (step SB3: Yes), the input / output unit 68 outputs output data indicating that the condition of the work implement 7 is poor (step SB4). The output data includes display data to be displayed on at least one of the display devices 56 and 59. The input / output unit 68 may cause at least one of the display devices 56 and 59 to display the display data indicating that the condition of the work implement 7 is poor.

[0083] If it is determined in step SB3 that the condition of the work implement 7 is not poor (step SB3: No), the input / output unit 68 outputs output data indicating that the condition of the work implement 7 is good (step SB5). The input / output unit 68 may cause at least one of the display devices 56 and 59 to display display data indicating that the condition of the work implement 7 is good.

[0084] <Effects> As described above, the diagnostic system 60 for the work machine 2 according to the embodiment includes a detection data acquisition unit 62 that acquires detection data on the angle of the work implement 7 of the work machine 2, and a calculation unit 65 that calculates the amount of natural descent ΔHa of the tip of the work implement 7 when the work lever 49, which is operated to operate the work implement 7, is in a neutral state, based on the angle detection data and dimensional data of the work implement 7.

[0085] According to this embodiment, the amount of natural descent ΔHa of the tip of the work implement 7 is calculated when the work lever 49 is in the neutral position while the work machine 2 is in operation. The diagnostic system 60 can efficiently calculate the amount of natural descent of the tip of the work implement 7 without causing the work of the work machine 2 to stop.

[0086] The calculation unit 65 calculates the amount of natural descent ΔHa each time the working lever 49 is brought into the neutral position during operation of the working machine 2. The diagnosis system 60 can constantly monitor the state of natural descent of the tip of the working implement 7.

[0087] [Second embodiment] A second embodiment will be described below. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the description of those components will be simplified or omitted.

[0088] In the above embodiment, an example has been described in which deterioration of at least one of the boom cylinder 11, the arm cylinder 12, the boom control valve 26, and the arm control valve 27 is estimated based on the amount of natural descent ΔHa of the tip of the arm 9. In the present embodiment, an example will be described in which a deteriorated component of the hydraulic system 23 is identified.

[0089] In this embodiment, the calculation unit 65 calculates a boom lowering amount ΔHb indicating the amount of natural lowering of the tip of the boom 8, based on the boom angle data and the boom length L1. The tip of the boom 8 includes an arm pin 15. The calculation unit 65 also calculates a natural lowering amount ΔHa of the tip of the arm 9, based on the boom angle data, the arm angle data, the boom length L1, and the arm length L2. In the following description, the natural lowering amount ΔHa of the tip of the arm 9 will be referred to as the work implement lowering amount ΔHa, as appropriate.

[0090] The calculation unit 65 can calculate the recorded value Ra based on the above-mentioned formula (1). The calculation unit 65 can calculate the recorded value Rb based on the following formula (2).

[0091]

number

[0092] In equation (2), the start time T1b of the neutral state of the working lever 49 is the same as the start time T1a in equation (1). In equation (2), the end time T2b of the neutral state of the working lever 49 is the same as the end time T2a in equation (1). In equation (2), the initial height H1b of the tip of the boom 8 is calculated based on the detection data of the angle of the boom 8 at the start time T1b of the neutral state and the dimensional data of the boom 8. In equation (2), the final height H2b of the tip of the boom 8 is calculated based on the detection data of the angle of the boom 8 at the end time T2b of the neutral state and the dimensional data of the boom 8.

[0093] The evaluation unit 67 determines the state of the boom 8 and the state of the arm 9 based on the recorded values Ra and Rb recorded in the recording unit 66. The determination of the state of the boom 8 includes a determination of deterioration of the components of the hydraulic system 23 that operates the boom 8. The determination of the state of the arm 9 includes a determination of deterioration of the components of the hydraulic system 23 that operates the arm 9.

[0094] The components of hydraulic system 23 that operate boom 8 are components of hydraulic system 23 through which hydraulic oil supplied to boom 8 or hydraulic oil discharged from boom 8 flows. The components of hydraulic system 23 that operate boom 8 include boom cylinder 11 and boom control valve 26. In the following description, the components of hydraulic system 23 that operate boom 8 will be collectively referred to as a boom operation circuit as appropriate.

[0095] The components of the hydraulic system 23 that operate the arm 9 are components of the hydraulic system 23 through which hydraulic oil supplied to the arm 9 or hydraulic oil discharged from the arm 9 flows. The components of the hydraulic system 23 that operate the arm 9 include the arm cylinder 12 and an arm control valve 27. In the following description, the components of the hydraulic system 23 that operate the arm 9 will be collectively referred to as an arm operating circuit as appropriate.

[0096] In this embodiment, the diagnostic system 60 determines whether the boom operating circuit and the arm operating circuit have deteriorated based on the boom lowering amount ΔHb and the work implement lowering amount ΔHa.

[0097] 13, 14, and 15 are diagrams illustrating a method for evaluating the work implement 7 by the evaluation unit 67 according to this embodiment. In the graphs shown in FIGS. 13, 14, and 15, the horizontal axis represents the operating time t of the work machine 2. The vertical axis represents the recorded values Ra and Rb. Line La represents the recorded value Ra calculated based on the work implement lowering amount ΔHa. Line Lb represents the recorded value Rb calculated based on the boom lowering amount ΔHb.

[0098] As shown in FIG. 13 , the evaluation unit 67 determines that the state of the boom operation circuit and the state of the arm operation circuit are good when the rate of change in the recorded value Rb calculated based on the boom lowering amount ΔHb is small and the rate of change in the recorded value Ra calculated based on the work implement lowering amount ΔHa is small. That is, the evaluation unit 67 determines that the state of the boom 8 and the state of the arm 9 are good when the rate of change in the boom lowering amount ΔHb is equal to or less than a predetermined boom threshold (fourth threshold) and the rate of change in the work implement lowering amount ΔHa is equal to or less than a predetermined work implement threshold (fifth threshold). That is, since the rate of change in the recorded value Rb (boom lowering amount ΔHb) is smaller than the line Lb shown in FIG. 13 , it is estimated that there is little leakage of hydraulic oil from the boom operation circuit. Since the line Lb and the line La shown in FIG. 13 overlap and the rate of change in the recorded value Rb (boom lowering amount ΔHb) and the rate of change in the recorded value Ra (work implement lowering amount ΔHa) are substantially the same, it is estimated that there is little leakage of hydraulic oil from the arm operation circuit.

[0099] 14, if the rate of change in recorded value Rb calculated based on boom lowering amount ΔHb is large and the rate of change in recorded value Ra calculated based on work implement lowering amount ΔHa is large, evaluation unit 67 determines that the condition of the boom operation circuit is poor and the condition of the arm operation circuit is good. That is, if the rate of change in boom lowering amount ΔHb exceeds a predetermined boom threshold (fourth threshold) and the rate of change in work implement lowering amount ΔHa exceeds a predetermined work implement threshold (fifth threshold), evaluation unit 67 determines that the condition of boom 8 is poor and the condition of arm 9 is good. That is, because the rate of change in recorded value Rb (boom lowering amount ΔHb) is large compared to line Lb shown in FIG. 14, it is estimated that there is a large amount of hydraulic oil leaking from the boom operation circuit. Since the lines Lb and La shown in Figure 14 overlap, and the rate of change of the recorded value Rb (boom descent amount ΔHb) and the rate of change of the recorded value Ra (work implement descent amount ΔHa) are substantially the same, it is estimated that there is little leakage of hydraulic oil from the arm operating circuit.

[0100] As shown in FIG. 15 , if the rate of change in the recorded value Rb calculated based on the boom lowering amount ΔHb is small and the rate of change in the recorded value Ra calculated based on the work implement lowering amount ΔHa is large, the evaluation unit 67 determines that the condition of the arm operation circuit is poor and the condition of the boom operation circuit is good. That is, if the rate of change in the boom lowering amount ΔHb is equal to or less than a predetermined boom threshold (fourth threshold) and the rate of change in the work implement lowering amount ΔHa exceeds a predetermined work implement threshold (fifth threshold), the evaluation unit 67 determines that the condition of the arm 9 is poor and the condition of the boom 8 is good. That is, because the rate of change in the recorded value Rb (boom lowering amount ΔHb) is smaller than the line Lb shown in FIG. 15 , it is estimated that there is little leakage of hydraulic oil from the boom operation circuit. Because the lines La and Lb shown in FIG. 15 do not overlap and the rate of change in the recorded value Ra (work implement lowering amount ΔHa) is greater than the rate of change in the recorded value Rb (boom lowering amount ΔHb), it is estimated that there is a lot of leakage of hydraulic oil from the arm operation circuit.

[0101] [Third embodiment] A third embodiment will be described below. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description of these components will be simplified or omitted.

[0102] In the above embodiment, an example has been described in which the work machine 2 is a hydraulic excavator and the amount of natural descent of the work implement 7 of the hydraulic excavator is calculated. In the present embodiment, an example will be described in which the work machine 102 is a wheel loader.

[0103] Figure 16 is a diagram schematically showing a work machine 102 according to this embodiment. The work machine 102 is a wheel loader. The work machine 102 comprises a vehicle body 112, an articulating device 113, a traveling device 115 including wheels 114, and a work implement 116. The work machine 102 travels around the work site using the traveling device 115. The work machine 102 performs work at the work site using the work implement 116. Examples of work that the work machine 102 can perform include excavation work, loading work, and transporting work.

[0104] The vehicle body 112 supports the work machine 116. The vehicle body 112 includes a front vehicle body portion 112F and a rear vehicle body portion 112R. The front vehicle body portion 112F is disposed forward of the rear vehicle body portion 112R.

[0105] The traveling device 115 supports the vehicle body 112. The traveling device 115 travels on the ground of a work site. The traveling device 115 includes wheels 114. The wheels 114 are attached to each of the front vehicle body 112F and the rear vehicle body 112R.

[0106] The work implement 116 is supported by the vehicle body 112. The work implement 116 is connected to the vehicle body front portion 112F. The work implement 116 has a boom 118, a bucket 119, a bell crank 120, a bucket link 121, a lift cylinder 122, and a bucket cylinder 123.

[0107] The base end of the boom 118 is rotatably connected to the front vehicle body 112F. The bucket 119 is a working member that excavates an excavation target. The base end of the bucket 119 is rotatably connected to the tip end of the boom 118. The middle portion of the bell crank 120 is rotatably connected to a bracket 124 of the boom 118. The lower end of the bell crank 120 is rotatably connected to the base end of a bucket link 121. The tip end of the bucket link 121 is rotatably connected to a bracket 125 of the bucket 119. The bell crank 120 is connected to the bucket 119 via the bucket link 121.

[0108] The boom 118 is operated by a lift cylinder 122. The lift cylinder 122 is a hydraulic cylinder. The base end of the lift cylinder 122 is connected to the front vehicle body 112F. The tip end of the lift cylinder 122 is connected to the boom 118. The bucket 119 is operated by a bucket cylinder 123. The bucket cylinder 123 is a hydraulic cylinder. The base end of the bucket cylinder 123 is connected to the front vehicle body 112F. The tip end of the bucket cylinder 123 is connected to the upper end of the bell crank 120.

[0109] As shown in Figure 16, when the work machine 102 loads excavated material into the dump body of the dump truck 170, the work machine 102 moves forward toward the dump truck 170 with the work implement 116 raised. When the work machine 102 moves forward toward the dump truck 170, the work lever that is operated to operate the work implement 116 is often in a neutral position. Even in the work machine 102 which is a wheel loader, the amount of natural descent of the tip of the work implement 116 when the work lever is in a neutral position is calculated.

[0110] [Fourth embodiment] A fourth embodiment will be described below. In the following description, the same or equivalent components as those in the above-described embodiments are denoted by the same reference numerals, and the description of these components will be simplified or omitted.

[0111] 17 is a diagram schematically showing a work machine 202 according to this embodiment. In this embodiment, an example will be described in which the work machine 202 is a bulldozer. The work machine 202 comprises a vehicle body 207, a traveling device 208, an excavator 209, and a ripper 210.

[0112] The excavation work machine 209 performs excavation work, earth-dozing work, or ground leveling work on a work target. The excavation work machine 209 is attached to the vehicle body 207. At least a portion of the excavation work machine 209 is disposed in front of the vehicle body 207.

[0113] The excavator 209 has an excavator blade 218 , a lift frame 219 , a tilt cylinder 216 , and a lift cylinder 217 .

[0114] The excavating blade 218 is disposed in front of the vehicle body 207. The excavating blade 218 has a cutting edge 218A.

[0115] The lift frame 219 supports the excavating blade 218. One end of the lift frame 219 is connected to the back of the excavating blade 218 via a pivoting mechanism. The other end of the lift frame 219 is connected to the vehicle body 207 via a pivoting mechanism. The other end of the lift frame 219 may be connected to the traveling device 208 via a pivoting mechanism.

[0116] The tilt cylinder 216 and the lift cylinder 217 each operate the excavation blade 218. The tilt cylinder 216 is driven to tilt the excavation blade 218. The lift cylinder 217 is driven to lift the excavation blade 218. The tilt operation of the excavation blade 218 refers to the operation of changing the tilt angle of the excavation blade 218. The lift operation of the excavation blade 218 refers to the operation of moving the excavation blade 218 in the up and down direction.

[0117] One end of the tilt cylinder 216 is connected to the back surface of the excavating blade 218 via a rotation mechanism. The other end of the tilt cylinder 216 is connected to the upper surface of the lift frame 219. The extension and contraction of the tilt cylinder 216 causes the excavating blade 218 to tilt.

[0118] One end of the lift cylinder 217 is connected to the lift frame 219 via a rotating mechanism. The other end of the lift cylinder 217 is connected to the vehicle body 207 via a rotating mechanism. The excavating blade 218 is lifted by the extension and contraction of the lift cylinder 217.

[0119] The ripper work machine 210 performs ripping work on a work object. The work object of the ripper work machine 210 includes the ground surface at the work site. The ripper work machine 210 is attached to the vehicle body 207. At least a portion of the ripper work machine 210 is disposed behind the vehicle body 207.

[0120] The ripper work machine 210 has a shank 232 , a ripper arm 234 , a tilt cylinder 235 , a lift cylinder 236 , and a beam 237 .

[0121] The shank 232 is disposed rearward of the vehicle body 207. The shank 232 has a ripper point 233. The ripper point 233 is provided at the lower end of the shank 232.

[0122] The ripper arm 234 supports the shank 232. The ripper arm 234 connects the vehicle body 207 and the shank 232. One end of the ripper arm 234 is connected to the rear of the vehicle body 207 via a rotating mechanism. The other end of the ripper arm 234 is connected to a beam 237.

[0123] The beam 237 is pivotally connected to the ripper arm 234. The shank 232 is connected to the ripper arm 234 via the beam 237.

[0124] The tilt cylinder 235 and the lift cylinder 236 each operate the shank 232. The tilt cylinder 235 and the lift cylinder 236 are each connected to the vehicle body 207. The tilt cylinder 235 is driven to perform a tilt operation on the shank 232. The lift cylinder 236 is driven to perform a lift operation on the shank 232. The tilt operation of the shank 232 refers to an operation that changes the tilt angle of the shank 232. The lift operation of the shank 232 refers to an operation that moves the shank 232 in the up and down direction.

[0125] One end of the tilt cylinder 235 is connected to the beam 237 via a rotation mechanism. The other end of the tilt cylinder 235 is connected to the rear of the vehicle body 207. The extension and contraction of the tilt cylinder 235 causes the shank 232 to tilt.

[0126] One end of the lift cylinder 236 is connected to the beam 237 via a rotation mechanism. The other end of the lift cylinder 236 is connected to the rear of the vehicle body 207. The extension and contraction of the lift cylinder 236 causes the shank 232 to perform a lifting operation.

[0127] The ripper work machine 210 rips the work target. In this embodiment, ripping by the ripper work machine 210 means that the traveling device 208 travels with the ripper point 233 stuck into the work target.

[0128] The work object is crushed by the traveling device 208 traveling in a ripping execution state in which the ripper point 233 rips the work object. Note that while the traveling device 208 is traveling, the shank 232 may perform a tilt operation or a lift operation.

[0129] Before the ripper work implement 210 rips the work object, the work lever that is operated to operate the ripper work implement 210 is often in a neutral position. In the work machine 202 that is a bulldozer, too, the amount of natural descent of the tip of the ripper work implement 210 when the work lever is in the neutral position is calculated.

[0130] [Other embodiments] In the first and second embodiments described above, the tip of the work implement 7 is the tip of the arm 9. The tip of the work implement 7 may be the cutting edge 10A of the bucket 10. When the tip of the work implement 7 is the cutting edge 10A of the bucket 10, the calculation unit 65 can calculate the position of the cutting edge 10A of the bucket 10 based on the boom angle θ1, the arm angle θ2, the bucket angle θ3, the boom length L1, the arm length L2, and the bucket length L3.

[0131] In the above-described embodiment, at least some of the functions of the controller 50 may be provided in the management server 3, or at least some of the functions of the management server 3 may be provided in the controller 50. For example, at least one of the recording unit 66, the evaluation unit 67, and the input / output unit 68 may be provided in the controller 50. At least one of the work machine data storage unit 61, the detection data acquisition unit 62, the operation data acquisition unit 63, the neutral state determination unit 64, and the calculation unit 65 may be provided in the management server 3.

[0132] In the above-described embodiment, each of the work machine data memory unit 61, the detection data acquisition unit 62, the operation data acquisition unit 63, the neutral state determination unit 64, the calculation unit 65, the recording unit 66, the evaluation unit 67, and the input / output unit 68 may be configured as separate hardware (computer systems).

[0133] In the above-described embodiment, the operator may operate the work machine 2 from a remote location at the work site 101, rather than being on board the work machine 2 to operate it. The remote control lever for remotely operating the work machine 2 may be located, for example, in the control room 100, or in a location different from the control room 100. When the work machine 2 is remotely operated, operation data of the remote operation lever at the remote location may be used to calculate the amount of natural descent of the work implement 7, instead of operation data of the work lever 49 of the work machine 2. [Explanation of symbols]

[0134] 1...management system, 2...work machine, 3...management server, 4...communication system, 5...traveling body, 5A...track, 6...swivel body, 7...work machine, 8...boom, 9...arm, 10...bucket, 10A...cutting edge, 11...boom cylinder, 11A...bottom chamber, 11B...rod chamber, 12...arm cylinder, 12A...bottom chamber, 12B...rod chamber, 13...bucket cylinder, 13A...bottom chamber, 13B...rod chamber, 14...boom pin, 15...arm pin, 16...bucket pin, 17...first link member, 18...second link member, 19...bucket cylinder top pin, 20...first link pin , 21...second link pin, 22...angle sensor, 23...hydraulic system, 24...engine, 25...hydraulic pump, 25A...swash plate, 26...boom control valve, 27...arm control valve, 28...bucket control valve, 29...tank, 43...neutral flow path, 44...negative control mechanism, 48...operation device, 49...working lever, 49L...left working lever, 49R...right working lever, 50...controller, 51...processor, 52...main memory, 53...storage, 54...interface, 55...input device, 56...display device, 57...on-board monitor, 58...input device, 59...display device, 60...diagnosis System, 61...work machine data storage unit, 62...detection data acquisition unit, 63...operation data acquisition unit, 64...neutral state determination unit, 65...calculation unit, 66...recording unit, 67...evaluation unit, 68...input / output unit, 70...dump truck, 100...control room, 101...work site, 102...work machine, 112...vehicle body, 112F...front body, 112R...rear body, 113...articulation device, 114...wheel, 115...traveling device, 116...work machine, 118...boom, 119...bucket, 120...bell crank, 121...bucket link, 122...lift cylinder, 123...bucket shelf Linda, 124...bracket, 125...bracket, 170...dump truck, 202...work machine, 207...body, 208...traveling device, 209...excavation work machine, 210...ripper work machine, 216...tilt cylinder, 217...lift cylinder, 218...digging blade, 219...lift frame, 221...boom angle sensor, 222...arm angle sensor, 223...bucket angle sensor, 232...shank, 233...ripper point, 234...ripper arm, 235...tilt cylinder, 236...lift cylinder, 237...beam, AX1...rotating axis, AX2...rotating axis,AX3...rotating axis, RX...swivel axis, θ1...boom angle, θ2...arm angle, θ3...bucket angle, L1...boom length, L2...arm length, L3...bucket length, LP...loading position.

Claims

1. a detection data acquisition unit that acquires detection data of the angle of a work implement of the work machine; a calculation unit that calculates a natural drop amount of the tip of the working machine when a working lever that is operated to operate the working machine is in a neutral state based on the angle detection data and dimensional data of the working machine, Diagnostic systems for work machines.

2. an operation data acquisition unit that acquires operation data of the operating lever; a neutral state determination unit that determines a start time and an end time of the neutral state based on the operation data, the calculation unit calculates an initial height of the tip of the work machine based on the angle detection data at the start time point, calculates a final height of the tip of the work machine based on the angle detection data at the end time point, and calculates the amount of natural descent based on the difference between the initial height and the final height. The diagnostic system for a work machine according to claim 1 .

3. the calculation unit calculates a recorded value based on a value obtained by dividing a difference between the initial height and the final height by a neutral state duration during which the neutral state continues; an evaluation unit that determines the state of the work machine based on the recorded value; The diagnostic system for a work machine according to claim 2.

4. The evaluation unit determines that the condition of the work machine is poor when the recorded value exceeds a first threshold value. The diagnostic system for a work machine according to claim 3.

5. the work implement includes a boom connected to a vehicle body of the work machine and an arm connected to the boom, The tip of the work machine is the tip of the arm.

2. The diagnostic system for a work machine according to claim 1.

6. the angle detection data includes boom angle data indicating an angle of the boom with respect to the vehicle body, and arm angle data indicating an angle of the arm with respect to the boom, the dimension data of the work machine includes a boom length indicating the length of the boom and an arm length indicating the length of the arm, The calculation unit calculating a boom lowering amount indicating a natural lowering amount of the tip of the boom based on the boom angle data and the boom length; calculating a work implement lowering amount indicating a natural lowering amount of the tip of the arm based on the boom angle data, the arm angle data, the boom length, and the arm length; an evaluation unit that determines a state of the boom and a state of the arm based on the boom lowering amount and the work implement lowering amount, The diagnostic system for a work machine according to claim 5.

7. The evaluation unit when the rate of change of the boom lowering amount is equal to or less than a second threshold value and the rate of change of the work implement lowering amount is equal to or less than a third threshold value, it is determined that the condition of the boom and the condition of the arm are good; When the rate of change of the boom lowering amount exceeds a second threshold value and when the rate of change of the work implement lowering amount exceeds a third threshold value, it is determined that the boom condition is poor; When the rate of change of the boom lowering amount is equal to or less than a second threshold value and the rate of change of the work implement lowering amount exceeds a third threshold value, it is determined that the condition of the arm is poor.

7. A diagnostic system for a work machine according to claim 6.

8. Obtaining detection data of the angle of a work implement of the work machine; and calculating a natural drop amount of the tip of the working machine when an operating lever operated to operate the working machine is in a neutral state based on the angle detection data and the dimensions of the working machine. A method for diagnosing a work machine.

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