System including work machine and load state estimation method for work

Abstract

The work machine (2) is attached to the work machine body (1). The plurality of strain sensors (11a, 11b, 11c, 11d) are disposed along a portion of the work machine (2) that intersects a virtual plane (PS). The controller (20) estimates the load state of the work machine (2) on the basis of the strain data detected by the plurality of strain sensors (11a, 11b, 11c, 11d).

Description

Technical Field

[0001] The present disclosure relates to a system including a work machine and a method for estimating a load state of the work machine. Background Art

[0002] Conventionally, a life prediction system for a working machine is disclosed in, for example, Japanese Patent Application Laid-Open No. 2022-124929 (Patent Document 1). In Patent Document 1, strain of a life prediction target portion is calculated based on operation information detected by an operation detection device.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-124929 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Measuring stress at multiple locations within a working machine during operation requires multiple strain gauges. However, installing multiple strain gauges complicates wiring. Furthermore, long-term strain monitoring requires a large device.

[0008] An object of the present disclosure is to provide a system including a working machine and a method for estimating a load state of the working machine, which are capable of grasping deformation of the entire working machine with a simple device configuration.

[0009] Means for solving problems

[0010] A system including a work machine disclosed herein comprises a work machine body, a work device, multiple strain sensors, and a controller. The work device is mounted on the work machine body. The multiple strain sensors are arranged along a portion of the work device that intersects an imaginary plane. The controller estimates a load state of the work device based on strain data detected by the multiple strain sensors.

[0011] Another system disclosed herein includes a work machine, comprising a work machine body, a work device, multiple strain sensors, and a controller. The work device is mounted on the work machine body. The multiple strain sensors are disposed at at least four locations on the work device. The controller estimates a load state of the work device based on strain data detected by the multiple strain sensors at the at least four locations.

[0012] Another system disclosed herein includes a work machine, comprising a work machine body, a work device, multiple strain sensors, a display device, and a controller. The work device is mounted on the work machine body. The multiple strain sensors are arranged along a portion of the work device that intersects an imaginary plane. The controller determines a load pattern of the work device based on strain data detected by the multiple strain sensors, estimates stress at any portion of the work device, and, if the estimated stress exceeds a predetermined threshold, displays the load pattern and the portion of the work device at which the estimated stress exceeds the predetermined threshold on the display device.

[0013] A method for estimating a load state of a working machine disclosed herein is a method for estimating a load state of a working machine having a working machine body and a working device mounted on the working machine body, and includes the following steps.

[0014] A plurality of strain sensors are arranged along a portion of the working machine that intersects the imaginary plane, and a load state of the working machine is estimated based on strain data detected by the plurality of strain sensors.

[0015] Another method for estimating a load state of a working machine disclosed herein is a method for estimating a load state of a working machine having a working machine body and a working device attached to the working machine body, and includes the following steps.

[0016] A plurality of strain sensors are arranged at at least four locations on the working machine, and a load state of the working machine is estimated based on strain data of the at least four locations detected by the plurality of strain sensors.

[0017] Still another method for estimating a load state of a working machine disclosed herein is a method for estimating a load state of a working machine including a working machine body, a working device attached to the working machine body, and a display device, and includes the following steps.

[0018] Multiple strain sensors are arranged along a portion of the working device that intersects an imaginary plane. A load pattern of the working device is determined based on strain data detected by the multiple strain sensors. Stress at any portion of the working device is estimated. If the estimated stress exceeds a predetermined threshold, the load pattern and the portion of the working device at which the estimated stress exceeds the predetermined threshold are displayed on a display device.

[0019] Effects of the Invention

[0020] According to the present disclosure, it is possible to realize a system including a working machine and a method for estimating a load state of the working machine, which are capable of grasping deformation of the entire working machine with a simple device configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a diagram showing the configuration of a hydraulic excavator as an example of a working machine in one embodiment of the present disclosure.

[0022] Figure 2 As Figure 1 This is a perspective view showing the structure of a boom as an example of a working device of the hydraulic excavator shown.

[0023] Figure 3 This is a cross-sectional view showing a state where a strain sensor is arranged on a cross section of the boom intersecting with an imaginary plane.

[0024] Figure 4 Yes Figure 1 Figure 2 shows the structure of the strain sensor.

[0025] Figure 5 Yes Figure 1 Diagram showing the functional blocks of the controller.

[0026] Figure 6 This is a flowchart showing a method for estimating a load state of a working machine in one embodiment of the present disclosure.

[0027] Figure 7 This is a diagram for explaining the load pattern of the working device and the stress acting on the working device.

[0028] Figure 8 Is used to illustrate Figure 7 Flowchart of the method for determining the load mode in .

[0029] Figure 9 This is a diagram for explaining a virtual plane intersecting the work machine. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present disclosure will be described based on the drawings.

[0031] In the specification and the drawings, the same reference numerals are used for the same or corresponding components, and repeated descriptions are omitted. In addition, in the drawings, the structure may be omitted or simplified for the sake of convenience.

[0032] In the following description, "up", "down", "front", "back", "left", and "right" refer to the person sitting on the Figure 1 The direction shown is based on the operator's seat 4S in the cab 4.

[0033] <Structure of operating machinery>

[0034] use Figure 1 The structure of a hydraulic excavator as an example of a working machine will be described.

[0035] Figure 1FIG is a diagram showing the structure of a hydraulic excavator as an example of a working machine in one embodiment of the present disclosure. Figure 1 As shown, a hydraulic excavator 10 includes a working machine body 1 and a working device 2 that operates hydraulically. The working machine body 1 includes a revolving body 3 and a traveling body 5 .

[0036] The traveling structure 5 includes a pair of crawler belts 5Cr and a traveling motor 5M. The hydraulic excavator 10 can travel by rotating the crawler belts 5Cr. The traveling motor 5M is provided as a driving source for the traveling structure 5.

[0037] The revolving body 3 is arranged on and supported by the traveling body 5. The revolving body 3 can be rotated relative to the traveling body 5 about a rotation axis RX by a revolving motor (not shown). The rotation axis RX is a virtual straight line that serves as the rotation center of the revolving body 3.

[0038] The revolving structure 3 includes a cab 4 (cab). A driver's seat 4S is provided within the cab 4 for the operator. The operator (passenger) rides in the cab 4 and can operate the work implement 2, rotate the revolving structure 3 relative to the traveling structure 5, and travel the hydraulic excavator 10 using the traveling structure 5.

[0039] The working device 2 is mounted on the working machine body 1. The working device 2 is supported by the revolving structure 3. The working device 2 includes a boom 6, an arm 7, and a bucket 8. The working device 2 also includes a boom cylinder 9a, an arm cylinder 9b, and a bucket cylinder 9c.

[0040] The boom 6 is rotatably connected to the working machine body 1. Specifically, the base end of the boom 6 is rotatably connected to the revolving body 3 with the boom base pin BF as a fulcrum. The boom 7 is rotatably connected to the boom 6. Specifically, the base end of the boom 7 is rotatably connected to the front end of the boom 6 with the boom top pin BT as a fulcrum. The bucket 8 is rotatably connected to the boom 7. Specifically, the base end of the bucket 8 is rotatably connected to the front end of the boom 7 with the boom top pin AT as a fulcrum.

[0041] The boom 6 can be driven by the boom cylinder 9a relative to the working machine body 1. By this driving, the boom 6 can be rotated in the vertical direction relative to the revolving unit 3 with the boom base pin BF as a fulcrum.

[0042] The arm 7 can be driven by the arm cylinder 9b relative to the boom 6. By this driving, the arm 7 can be rotated relative to the boom 6 in the vertical direction or the front-rear direction with respect to the boom 6 using the boom top pin BT as a fulcrum.

[0043] The bucket 8 can be driven by the bucket cylinder 9c relative to the arm 7. By this driving, the bucket 8 can be rotated in the vertical direction relative to the arm 7 with the arm top pin AT as a fulcrum.

[0044] Load state estimation system for operating machinery

[0045] Next, use Figures 1 to 5 A load state estimation system for a working machine will be described.

[0046] Figure 2 As Figure 1 This is a perspective view showing the structure of a boom as an example of a working device in the hydraulic excavator shown. Figure 3 This is a cross-sectional view showing a state where a strain sensor is arranged on a cross section of the boom intersecting with an imaginary plane. Figure 4 Yes Figure 1 Figure 2 shows the structure of the strain sensor. Figure 5 Yes Figure 1 Diagram showing the functional blocks of the controller.

[0047] like Figure 1 As shown, the load state estimation system for the working machine 10 in this embodiment estimates the load state of the working machine 2 in the working machine 10, for example. The working machine 2 whose load state is estimated is, for example, the working machine 2 of the hydraulic excavator 10, specifically the boom 6 or the arm 7. The load state of the working machine 2 includes the stress and load pattern of the working machine 2.

[0048] It should be noted that the work implement 2 for estimating the load state may be a work implement of another working machine such as a wheel loader other than the hydraulic excavator 10. Hereinafter, the boom 6 will be described as an example of the work implement 2 for estimating the load state.

[0049] The load state estimation system of the working machine 10 in the present embodiment includes a plurality of strain sensors 11 a , 11 b , 11 c , and 11 d , a controller 20 , and an output device 30 .

[0050] The plurality of strain sensors 11a, 11b, 11c, and 11d are, for example, four strain sensors. The plurality of strain sensors 11a, 11b, 11c, and 11d are mounted on the work implement 2 for which the load state is to be estimated. The plurality of strain sensors 11a, 11b, 11c, and 11d are, for example, mounted on the boom 6. The plurality of strain sensors 11a, 11b, 11c, and 11d may also be mounted on the arm 7, for example.

[0051] like Figure 2As shown, multiple strain sensors 11a, 11b, 11c, and 11d are arranged along the portion of the boom 6 that intersects with an imaginary plane PS. The imaginary plane PS is located closer to the working machine body 1 than the center of the boom 6 in the longitudinal direction L. The imaginary plane PS is located closer to the boom base pin hole BFH than an imaginary straight line VL2, which passes through the center C of an imaginary straight line VL1 connecting the boom base pin hole BFH and the boom top pin hole BTH and is perpendicular to the imaginary straight line VL1 when viewed from the side of the boom 6. Furthermore, the imaginary plane PS is located closer to the boom base pin hole BFH than the boom cylinder mounting hole BCH.

[0052] like Figure 3 As shown, the boom 6 has two transverse plates 6a and 6b and two longitudinal plates 6c and 6d. The transverse plates 6a and 6b consist of a lower plate 6a and an upper plate 6b. The longitudinal plates 6c and 6d consist of a left plate 6c and a right plate 6d. The transverse plates 6a and 6b are arranged approximately parallel to each other. The longitudinal plates 6c and 6d are arranged approximately parallel to each other. For example, the longitudinal plates 6c and 6d are sandwiched between the transverse plates 6a and 6b.

[0053] exist Figure 3 shows a cross section of the boom 6 intersecting the imaginary plane PS. The boom 6 has a rectangular frame-like cross section formed by two horizontal plates 6a and 6b and two vertical plates 6c and 6d. The rectangular frame-like cross section of the boom 6 has four corners CO1, CO2, CO3, and CO4.

[0054] Multiple strain sensors 11a, 11b, 11c, and 11d are attached to the outer periphery of the rectangular frame of the boom 6. Multiple strain sensors 11a, 11b, 11c, and 11d may also be attached to the inner periphery of the rectangular frame. For example, the strain sensors 11a and 11b are attached to the lower plate 6a. For example, the strain sensors 11c and 11d are attached to the upper plate 6b. The strain sensors 11a, 11b, 11c, and 11d may also be attached to the vertical plates 6c and 6d. Each of the multiple strain sensors 11a, 11b, 11c, and 11d is secured to the boom 6 using, for example, an adhesive.

[0055] Multiple strain sensors 11a, 11b, 11c, and 11d are disposed at at least three corners CO1, CO2, and CO3 of the four corners CO1, CO2, CO3, and CO4 of the boom 6. A corner includes an area from the connection between the horizontal plate and the vertical plate to the nearest corner, and an area from the opposite area of ​​the connection across the horizontal plate or the vertical plate to the nearest corner.

[0056] Therefore, the corner CO1 includes an area R1A from the connection CP1 between the lower plate 6a and the left plate 6c to the corner C1, and an area R1B from the area opposite to the connection CP1 to the corner C1. The corner CO2 includes an area R2A from the connection CP2 between the lower plate 6a and the right plate 6d to the corner C2, and an area R2B from the area opposite to the connection CP2 to the corner C2. The corner CO3 includes an area R3A from the connection CP3 between the upper plate 6b and the left plate 6c to the corner C3, and an area R3B from the area opposite to the connection CP3 to the corner C3. The corner CO4 includes an area R4A from the connection CP4 between the upper plate 6b and the right plate 6d to the corner C4, and an area R4B from the area opposite to the connection CP4 to the corner C4. It should be noted that in Figure 4 Corners CO1, CO2, CO3, and CO4 are indicated by thick lines.

[0057] In this embodiment, strain sensor 11a is disposed at corner CO1. Strain sensor 11b is disposed at corner CO2. Strain sensor 11c is disposed at corner CO3. Strain sensor 11d is disposed between corners CO3 and CO4. Strain sensor 11d is disposed, for example, at the center of the width direction of upper plate 6b.

[0058] The plurality of strain sensors 11a, 11b, 11c, and 11d are arranged on at least two different surfaces. The strain sensors 11a and 11b are arranged on the outer peripheral surface of the lower plate 6a, and the strain sensors 11c and 11d are arranged on the outer peripheral surface of the upper plate 6b.

[0059] The strain sensors 11a and 11b may be disposed on, for example, the inner peripheral surface of the lower plate 6a. The strain sensors 11c and 11d may be disposed on, for example, the inner peripheral surface of the upper plate 6b.

[0060] like Figure 4 As shown, strain sensors 11a, 11b, 11c, and 11d each include a strain gauge 12, a bridge circuit 13, and a strain amplifier 14. The strain gauge 12 is connected to the working device 2 (e.g., the boom 6) and expands and contracts along with the working device 2. As the strain gauge 12 expands and contracts, the wire of the strain gauge 12 expands and contracts. This change in cross-sectional area of ​​the wire causes a change in resistance of the wire. The strain sensor detects strain by measuring this change in resistance of the wire.

[0061] The bridge circuit 13 is provided to accurately measure the resistance of the metal wire of the strain gauge 12. The bridge circuit 13 converts changes in the resistance of the metal wire into changes in voltage. Since the voltage converted from the resistance by the bridge circuit 13 is small, a strain amplifier 14 is provided to amplify the voltage.

[0062] In each of the strain sensors 11a, 11b, 11c, and 11d, at least the strain gauge 12 and the bridge circuit 13 are formed of semiconductor devices. The strain gauge 12 and the bridge circuit 13 may be formed of a single semiconductor device that includes both the strain gauge 12 and the bridge circuit 13, or they may be formed of different semiconductor devices. Furthermore, the strain amplifier 14 may also be formed of a semiconductor device. Furthermore, the strain amplifier 14 may be provided in the same semiconductor device as the strain gauge 12 and the bridge circuit 13, or it may be provided in a different semiconductor device from the strain gauge 12 and the bridge circuit 13.

[0063] like Figure 5 As shown, the controller 20 estimates the load state of the work machine 2 based on the strain data detected by the plurality of strain sensors 11a, 11b, 11c, and 11d. The controller 20 estimates the load state of the work machine 2 based on the strain data of at least four locations of the boom 6.

[0064] The controller 20 estimates stress at an arbitrary portion of the work machine 2 based on strain data detected by the plurality of strain sensors 11 a , 11 b , 11 c , and 11 d .

[0065] The controller 20 calculates the amount of damage to the work machine 2 based on the strain data detected by the plurality of strain sensors 11a, 11b, 11c, and 11d. The controller 20 displays the life of the work machine 2 predicted from the cumulative value of the damage on the display device 31.

[0066] When the estimated stress is greater than a predetermined threshold value, the controller 20 outputs an alarm signal to the notification device 32 .

[0067] The controller 20 includes a processor, main memory, and storage. The processor is, for example, a CPU (Central Processing Unit). Main memory includes, for example, nonvolatile memory such as ROM (Read Only Memory) and volatile memory such as RAM (Random Access Memory). The controller 20 reads programs stored in storage, expands them in the main memory, and executes the specified processing according to the programs.

[0068] The controller 20 and the output device 30 may be mounted on the hydraulic excavator 10 or separately located outside the hydraulic excavator 10. If the controller 20 and the output device 30 are separately located outside the hydraulic excavator 10, they may each be wirelessly connected to the strain sensors 11a, 11b, 11c, 11d, etc. The controller 20 may also be stored on a server remote from the hydraulic excavator 10. Furthermore, by removing the output device 30 from the hydraulic excavator 10, an administrator can view the display device 31 remotely from the hydraulic excavator 10 and recognize notification information from the notification device 32. If the output device 30 is mounted on the hydraulic excavator 10, a user on board the hydraulic excavator 10 can view the display device 31 mounted on the hydraulic excavator 10 and recognize notification information from the notification device 32. At least one of the controller 20 and the output device 30 may be mounted on a portable information terminal such as a smartphone, tablet computer, or personal computer.

[0069] The controller 20 includes a strain acquisition unit 21, a load state estimation unit 22, a damage amount calculation unit 23, a life prediction unit 24, a storage unit 25, an output device control unit 26, and a stress determination unit 27. The strain acquisition unit 21 acquires strain data detected by the strain sensors 11a, 11b, 11c, and 11d. The strain acquisition unit 21 outputs the acquired strain data to the load state estimation unit 22.

[0070] The load state estimation unit 22 includes a stress estimation unit 22a and a load pattern determination unit 22b. The stress estimation unit 22a estimates stress at any location on the work machine 2 based on the acquired strain data. To estimate stress, the stress estimation unit 22a refers to data representing the stress distribution at various locations on the work machine 2, stored in the storage unit 25. By referring to this stress distribution data, the stress estimation unit 22a can estimate the stress distribution of the entire work machine 2 based on the strain data detected by the strain sensors 11a, 11b, 11c, and 11d. Furthermore, the stress estimation unit 22a can estimate stress values ​​at critical parts of the work machine 2. Critical parts of the work machine 2 are those locations on the work machine 2 where cracks are most common, typically corresponding to welds. The stress estimation unit 22a outputs a signal representing the estimated stress to the damage calculation unit 23 and the stress determination unit 27.

[0071] The load pattern determination unit 22b determines the load pattern of the work machine 2 based on the acquired strain data. When determining the load pattern, the load pattern determination unit 22b refers to a predetermined value stored in the storage unit 25. The load pattern determination unit 22b outputs a signal indicating the determined load pattern to the output device control unit 26.

[0072] The damage calculation unit 23 calculates the damage amount of the working device based on the acquired signal indicating stress. The damage amount is calculated using the rain flow method based on the stress value. The damage calculation unit 23 outputs a signal indicating the calculated damage amount to the life prediction unit 24.

[0073] The life prediction unit 24 predicts the life of the work machine 2 based on the acquired damage amount. The life prediction unit 24 predicts the life of the work machine 2 based on the cumulative value of the damage amount. The life prediction unit 24 outputs a signal indicating the predicted life to the output device control unit 26.

[0074] The stress determination unit 27 determines whether the acquired stress is greater than a predetermined threshold value. When making this determination, the stress determination unit 27 refers to the predetermined threshold value stored in the storage unit 25. The stress determination unit 27 outputs a signal indicating the determination result to the output device control unit 26.

[0075] The output device control unit 26 controls the output device 30 by outputting a control command to the output device 30 based on the received signal. The output device control unit 26 controls the output device 30 so that the lifespan received from the lifespan prediction unit 24 is displayed on the display device 31. When the output device control unit 26 receives a determination result from the stress determination unit 27 that the stress estimated by the stress estimation unit 22a is greater than a predetermined threshold, it outputs an alarm signal to the output device 30. The notification unit 32 of the output device 30 issues an alarm based on this alarm signal.

[0076] In addition, when the output device control unit 26 obtains a judgment result from the stress judgment unit 27 that the stress estimated by the stress estimation unit 22a is greater than a prescribed threshold value, it controls the display device 31 so that the load pattern when the estimated stress is greater than the prescribed threshold value and the part of the working device 2 where the estimated stress is greater than the prescribed threshold value are displayed.

[0077] <Method for estimating the load status of operating machinery>

[0078] Next, use Figure 5 and Figure 6 A method of estimating the load state of a working machine in this embodiment will be described.

[0079] Figure 6 FIG. 1 is a flowchart showing a method for estimating a load state of a working machine in one embodiment of the present disclosure. Figure 5 and Figure 6 As shown, in this embodiment, the strain of the working device 2 (for example, the boom 6) is detected by a plurality of strain sensors 11a, 11b, 11c, and 11d (step S1: Figure 6The strain acquisition unit 21 of the controller 20 acquires the strain data of the boom 6 detected by the plurality of strain sensors 11 a , 11 b , 11 c , and 11 d (step S2 : Figure 6 ).

[0080] The load state estimating unit 22 of the controller 20 estimates the load state of the boom 6 based on the acquired strain data. The load state of the working device 2 includes the stress of the working device 2 and the load pattern of the working device 2. The stress of the working device 2 is estimated by the stress estimating unit 22a of the controller 20 (step S3: Figure 6 ), the load pattern of the working device 2 is determined by the load pattern determination unit 22b of the controller 20 (step S10: Figure 6 ).

[0081] The stress estimating unit 22a of the controller 20 estimates the stress at any part of the working machine 2 based on the acquired strain data. When estimating the stress, the stress estimating unit 22a refers to the data representing the stress distribution of each part of the working machine 2 stored in the storage unit 25. Thus, the stress value of the key part of the working machine 2 is estimated (step S3: Figure 6 The stress estimating unit 22 a outputs a signal indicating the estimated stress to the damage amount calculating unit 23 and the stress determining unit 27 .

[0082] The load pattern determination unit 22b of the controller 20 determines the load pattern of the work machine 2 based on the strain data acquired from the strain acquisition unit 21 (step S10: Figure 6 ). When the load mode determination unit 22b determines the load mode, it follows the Figure 8 The load pattern determination unit 22b refers to the prescribed value stored in the storage unit 25 during the determination. The load pattern determination unit 22b outputs a signal indicating the determined load pattern to the output device control unit 26.

[0083] The damage amount calculation unit 23 of the controller 20 calculates the damage amount of the working machine 2 based on the acquired signal indicating the stress (step S4: Figure 6 The damage amount is calculated based on the stress value using the rain flow method. The damage amount calculation unit 23 outputs a signal indicating the calculated damage amount to the life prediction unit 24.

[0084] The life prediction unit 24 of the controller 20 predicts the life of the working machine 2 based on the acquired damage amount. The life prediction unit 24 predicts the life of the working machine 2 based on the cumulative value of the damage amount (step S5: Figure 6 The life prediction unit 24 outputs a signal indicating the predicted life to the output device control unit 26 .

[0085] The output device control unit 26 displays the life on the display device 31 based on the acquired signal indicating the life (step S6: Figure 6 ).

[0086] The stress determination unit 27 of the controller 20 determines whether the stress value obtained from the stress estimation unit 22a is greater than a predetermined threshold value (step S7: Figure 6 When making this determination, the stress determination unit 27 refers to the predetermined threshold value stored in the storage unit 25. If the stress determination unit 27 determines that the stress value is less than the predetermined threshold value, the stress value estimation (step S3) and stress value determination (step S7) are repeated.

[0087] If the stress determination unit 27 determines that the stress value is greater than a predetermined threshold, the load pattern acting on the work device 2 and the portion of the work device 2 where the stress value is greater than the predetermined threshold are displayed on the display device 31 (step S8a). If the stress determination unit 27 determines that the stress value is greater than the predetermined threshold, the notification device 32 issues an alarm (warning) (step S8b).

[0088] <Load mode determination method>

[0089] Next, use Figure 7 and Figure 8 A method of determining a load pattern in this embodiment will be described.

[0090] Figure 7 This is a diagram for explaining the load pattern of the working device and the stress acting on the working device. Figure 8 Is used to illustrate Figure 6 Flowchart of the method for determining the load mode in .

[0091] Mining mode in load mode ( Figure 7 (A)) assumes that the boom 6 or arm 7 is lowered. The lateral pressure mode in the load mode ( Figure 7 (B)) assumes that the revolving body 3 rotates to the right or left and the side of the bucket 8 contacts an object. Figure 7 (C) Assume that the boom 6 is lowered while the arm 7 is extended forward, the revolving unit 3 is rotated to the right or left, and the side surface of the bucket 8 contacts an object.

[0092] It should be noted that in Figure 7 In (D), (E), and (F), the symbol “-(negative)” indicates compressive stress, and the symbol “+(positive)” indicates tensile stress. Figure 7In (D), (E), and (F), the hollow area represents the magnitude of the compressive stress acting on the working device 2 , and the dotted hatched area represents the magnitude of the tensile stress acting on the working device 2 .

[0093] The present inventors have conducted in-depth research on methods for estimating the stress of the entire working device 2 using a relatively small number of strain sensors. The inventors focused on the fact that bending and torsion acting on the working device 2 produce different characteristics in the cross section of the working device 2 under different load modes. Here, as examples of load modes, excavation mode, extension and lateral pressure mode are listed. However, load modes are not limited to these and may also include high-altitude surface impact mode, crushing mode, and the like.

[0094] First, in the case where the upper and lower bending acts on the working device 2, as shown in FIG. Figure 7 As shown in (D), in a cross section of the working device intersecting the imaginary plane 2, high stresses (denoted by the same reference numerals) act on both the corners and the center of the plates, while stresses (denoted by different reference numerals) are generated on the upper and lower plates 6a and 6b. In this case, for example, high tensile stress acts across the entire width of the lower surface (outer peripheral surface) of the lower plate 6a, while high compressive stress acts across the entire width of the upper surface (outer peripheral surface) of the upper plate 6b. In cases where vertical bending occurs, for example, high compressive stress acts across the entire width of the lower surface of the lower plate 6a, while high tensile stress acts across the entire width of the upper surface of the upper plate 6b.

[0095] In addition, when the torsion acts on the working device 2, as shown in FIG. Figure 7 As shown in (E), in a cross section of the working device 2 intersecting the imaginary plane, stresses with different reference numerals act on the left and right sides of the upper and lower plates 6a and 6b, while stresses with the same reference numerals act on the diagonal corners of the upper and lower plates. In this case, for example, a stress that transitions from tensile stress to compressive stress acts on the lower surface of the lower plate 6a from the left end to the right end, while a stress that transitions from compressive stress to tensile stress acts on the upper surface of the upper plate 6b from the left end to the right end. In the case of torsion, for example, a stress that transitions from compressive stress to tensile stress acts on the lower surface of the lower plate 6a from the left end to the right end, while a stress that transitions from tensile stress to compressive stress acts on the upper surface of the upper plate 6b from the left end to the right end.

[0096] In addition, when left and right bending acts on the working device 2, as shown in FIG. Figure 7As shown in (F), in a cross section of the working device intersecting an imaginary plane 2, stresses with different reference numerals act on the left and right sides of the upper and lower plates, and stresses with different reference numerals act on the diagonals of the upper and lower plates. In this case, for example, a stress transitioning from tensile stress to compressive stress acts on the lower surface of lower plate 6a and the upper surface of upper plate 6b, respectively, from the left end to the right end. In the case of left-right bending, for example, a stress transitioning from compressive stress to tensile stress acts on the lower surface of lower plate 6a and the upper surface of upper plate 6b, respectively, from the left end to the right end.

[0097] In mining mode, Figure 7 As shown in (A), the vertical load acts strongly on the load point P. Therefore, in the excavation mode, Figure 7 As shown in (D), the influence of the upper and lower bending becomes stronger in the upper and lower plates 6a and 6b. In the cross section of the working device 2, high stresses with the same reference numerals act on both the corners and the center of the upper and lower plates 6a and 6b, and stresses with different reference numerals are generated in the upper and lower plates 6a and 6b.

[0098] In addition, in the horizontal pressure mode, if Figure 7 As shown in (B), the load in the left and right directions acts on the load point P, so the torsion acts on the left and right of the upper and lower plates. Figure 7 As shown in (E), stresses with different reference numerals act on the left and right sides of the upper and lower plates 6a and 6b, respectively, and stresses with the same reference numerals act on diagonal corners of the upper and lower plates 6a and 6b.

[0099] In addition, in the stretch-side pressure mode, if Figure 7 As shown in (B), when the working device 2 is fully extended, the left and right loads act on the load point P, so the left and right bending and torsion act on the left and right of the upper and lower plates. Figure 7 As shown in (E), stresses with different reference numerals act on the left and right sides of the upper and lower plates 6a and 6b, respectively, while stresses with the same reference numerals act on the diagonal corners of the upper and lower plates 6a and 6b. Furthermore, in the extension and lateral compression mode of the working device 2, the stress on the upper surface of the upper plate 6b is lower than in the lateral compression mode due to the influence of lateral bending.

[0100] Based on the above, in the cross section of the working device 2 intersecting the imaginary plane PS, if the Figure 3 Since the stress at the shown point B2 is a compressive stress and a high stress (large absolute value), it can be determined that the load mode is the excavation mode.

[0101] In addition, in the cross section of the working device 2 intersecting the imaginary plane PS, the Figure 3) is not a compressive stress or is not a high stress, it can be determined whether the load mode is a lateral compression mode or an extension lateral compression mode.

[0102] Furthermore, if the value obtained by dividing the stress value at point B1 by the average of the absolute values ​​of the stress values ​​at points B3 and B4 in the cross section of the work machine 2 intersecting the imaginary plane PS is equal to or less than a predetermined value, it can be determined that the load mode is the extension-lateral compression mode.

[0103] Furthermore, if the stress value at point B1 in the cross section of the work machine 2 intersecting the imaginary plane PS is greater than a predetermined value, divided by the average of the absolute stress values ​​at points B3 and B4, the load mode can be determined to be the lateral pressure mode.

[0104] As mentioned above, it is possible to Figure 8 The load mode is determined by the process shown in the figure. Figure 8 As shown, the load mode determination unit 22b determines whether the stress value at point B2 is a compressive value (step S11a). If the stress value at point B2 is a compressive value, the load mode determination unit 22b determines whether the stress value at point B2 is greater than or equal to a predetermined value (step S11b). If the stress value at point B2 is greater than or equal to the predetermined value, the load mode determination unit 22b determines that the load mode is the excavation mode (step S11c).

[0105] On the other hand, if the stress value at point B2 is not a compressive value or is less than a predetermined value, the load mode determination unit 22b determines whether the value obtained by dividing the stress value at point B1 by the average of the absolute values ​​of the stress values ​​at points B3 and B4 is less than or equal to a predetermined value (step S11d). If the value obtained by dividing the stress value at point B1 by the average of the absolute values ​​of the stress values ​​at points B3 and B4 is less than or equal to a predetermined value, the load mode determination unit 22b determines that the load mode is the extension-compression mode (step S11e). Furthermore, if the value obtained by dividing the stress value at point B1 by the average of the absolute values ​​of the stress values ​​at points B3 and B4 is greater than a predetermined value, the load mode determination unit 22b determines that the load mode is the compression mode (step S11f).

[0106] Effects

[0107] Next, the effects of this embodiment will be described.

[0108] In this embodiment, if Figure 5As shown, the controller 20 estimates the load state of the work machine 2 based on strain data detected by multiple strain sensors 11a, 11b, 11c, and 11d. This allows users or administrators to determine the load state of the work machine 2 using a relatively small number of strain sensors 11a, 11b, 11c, and 11d. This allows users or administrators to understand the overall load state of the work machine 2 using a simple device configuration. Furthermore, the used vehicle valuation of the hydraulic excavator 10 can be calculated based on the estimated load state. This allows for appropriate used vehicle valuations, such as reducing the valuation of hydraulic excavators 10 that frequently experience heavy loads. Furthermore, based on the estimated load state, information about service procedures, such as inspections of the work machine 2 itself and grease supply to each axis of the work machine 2, can be automatically sent to the user or administrator. Furthermore, by effectively utilizing this data, service personnel can provide driving guidance and crack inspection recommendations to the driver, thereby reducing downtime and preventing driving that places excessive loads on the work machine 2.

[0109] In this embodiment, if Figure 5 As shown, the controller 20 estimates the load state of the working device 2 based on the strain data of at least four parts detected by multiple strain sensors 11a, 11b, 11c, and 11d. In this way, the load pattern of the working device 2 can be estimated, and the stress acting on the working device 2 can be estimated. Therefore, the deformation of the working device 2 as a whole can be grasped with a simple device structure. In addition, the second-hand vehicle valuation of the hydraulic excavator 10 can also be calculated based on the estimated load state. In this way, the valuation of the hydraulic excavator 10 that is frequently subjected to heavy loads can also be reduced. In addition, based on the estimated load state, information on service procedures such as inspection of the working device 2 itself and grease supply to each axis of the working device 2 can be automatically sent to the user or manager. In addition, service personnel can also effectively use the obtained data to shorten downtime through recommendations such as driving guidance and crack inspection.

[0110] In this embodiment, if Figure 5 As shown, the load pattern includes at least excavation. Thus, the user or manager can know the load pattern acting on the working device 2.

[0111] In this embodiment, if Figure 5 As shown, the load pattern includes at least lateral pressure and extension lateral pressure. Thus, the user or manager can know the load pattern acting on the working device 2.

[0112] In this embodiment, if Figure 5As shown, the controller 20 estimates stress at any location on the work machine 2 based on strain data detected by multiple strain sensors 11a, 11b, 11c, and 11d. This allows users or administrators to determine the overall stress of the work machine 2 using a relatively small number of strain sensors 11a, 11b, 11c, and 11d. Furthermore, users or administrators can determine stress acting on key components of the work machine 2. The stress at these key components can be used for registration, setting target lifespans during design, or setting specific stresses based on intended use.

[0113] In this embodiment, if Figure 3 As shown, a plurality of strain sensors 11a, 11b, and 11c are arranged at at least three corners CO1, CO2, and CO3 of the work machine 2. This enables determination of the load pattern.

[0114] In this embodiment, if Figure 3 As shown, the plurality of strain sensors 11a, 11b, 11c, and 11d are arranged on at least two different surfaces.

[0115] In this embodiment, if Figure 2 As shown, the imaginary plane PS is located closer to the work machine body 1 than the center of the longitudinal direction L of the work implement 2 (the imaginary straight line VL2). Consequently, even when multiple strain sensors 11a, 11b, 11c, and 11d are arranged along the imaginary plane PS1, the wiring path is shortened, thereby preventing wire breakage. Furthermore, damage or malfunction of the multiple strain sensors 11a, 11b, 11c, and 11d during operation can be prevented.

[0116] In this embodiment, if Figure 5 As shown, the controller 20 calculates the amount of damage to the work machine 2 based on the strain data detected by the plurality of strain sensors 11a, 11b, 11c, and 11d, and displays the life of the work machine 2 predicted based on the cumulative value of the damage on the display device 31. This allows a user or administrator to easily check the life of the work machine 2.

[0117] In this embodiment, if Figure 5 As shown, the controller 20 outputs an alarm signal when the estimated stress exceeds a predetermined threshold. This allows the user or administrator to easily detect stresses exceeding the threshold acting on the work machine 2. Furthermore, the alarm allows the user or administrator to detect the possibility of abnormal use or dangerous driving of the hydraulic excavator 10. Furthermore, in the event of abnormal use or dangerous driving, an alarm can be issued in real time based on the stress.

[0118] In this embodiment, if Figure 5As shown, the controller 20 determines the load pattern of the hydraulic excavator 10 based on strain data and estimates stress at any location on the work implement 2 (e.g., the boom 6). Furthermore, if the estimated stress exceeds a predetermined threshold, the controller 20 displays the load pattern and the location on the work implement 2 where the estimated stress exceeded the threshold on the display device 31. This allows users or administrators to easily identify the load pattern and the locations where stresses exceeding the threshold are acting. This allows for the understanding of overall deformation of the work implement with a simple device configuration. Furthermore, the used vehicle valuation of the hydraulic excavator 10 can be calculated based on the estimated load status. This can also reduce the valuation of hydraulic excavators 10 that are frequently subjected to heavy loads. Furthermore, based on the estimated load status, information about service procedures, such as inspections of the work implement 2 itself and grease supply to each axis of the work implement 2, can be automatically sent to users or administrators. Furthermore, service personnel can effectively utilize the resulting data to provide recommendations such as driving guidance and crack inspections, thereby reducing downtime.

[0119] In this embodiment, if Figure 4 As shown, each of the plurality of strain sensors 11a, 11b, 11c, and 11d includes a strain gauge 12 and a bridge circuit 13. The strain gauge 12 and the bridge circuit 13 are formed of semiconductor devices, thereby enabling miniaturization of the strain gauge.

[0120] <Other>

[0121] like Figure 9 As shown, the imaginary plane PS intersecting the work machine 2 may be a plane PS1 parallel to the short side direction W of the work machine 2 or a plane PS2 not parallel to the short side direction W of the work machine 2 .

[0122] <Note>

[0123] The above description includes the following additional features.

[0124] (Note 1)

[0125] A system comprising a work machine, wherein:

[0126] The system has:

[0127] The main body of the operating machinery;

[0128] A working device installed on the working machine body;

[0129] a plurality of strain sensors arranged along a portion of the working device intersecting the imaginary plane; and

[0130] A controller estimates a load state of the working device based on strain data detected by the plurality of strain sensors.

[0131] (Note 2)

[0132] A system comprising a work machine, wherein:

[0133] The system has:

[0134] The main body of the operating machinery;

[0135] A working device installed on the working machine body;

[0136] a plurality of strain sensors disposed at at least four locations of the working device; and

[0137] A controller estimates a load state of the working device based on the strain data of the at least four locations detected by the plurality of strain sensors.

[0138] (Note 3)

[0139] The system including the working machine according to Supplement 1 or Supplement 2, wherein:

[0140] The working device is a boom or a dipper arm,

[0141] The load state of the working device includes a load mode of the working device,

[0142] The load pattern includes at least excavation.

[0143] (Note 4)

[0144] The system including the working machine according to any one of Supplementary Notes 1 to 3, wherein:

[0145] The working machine includes a rotary body,

[0146] The load state of the working device includes a load mode of the working device,

[0147] The load mode includes at least lateral compression and extensional lateral compression.

[0148] (Note 5)

[0149] The system including the working machine according to any one of Supplementary Notes 1 to 4, wherein:

[0150] The working device is a boom or a dipper arm,

[0151] The load state of the working device includes the stress of the working device,

[0152] The controller estimates stress at an arbitrary portion of the working device based on strain data detected by the plurality of strain sensors.

[0153] (Note 6)

[0154] The system including the working machine according to any one of Supplementary Notes 1 to 5, wherein:

[0155] The working device is a boom or a dipper arm,

[0156] The plurality of strain sensors are disposed at at least three corners of the working device.

[0157] (Note 7)

[0158] The system including the working machine according to any one of Supplementary Notes 2 to 6, wherein:

[0159] The working device is a boom or a dipper arm,

[0160] The plurality of strain sensors are arranged on at least two different surfaces.

[0161] (Note 8)

[0162] The system including the working machine according to any one of Supplementary Notes 1 to 7, wherein:

[0163] The working device is a boom or a dipper arm,

[0164] The imaginary plane is located closer to the working machine body than the center in the longitudinal direction of the working device.

[0165] (Note 9)

[0166] The system including the working machine according to any one of Supplementary Notes 1 to 8, wherein:

[0167] The system further comprises a display device,

[0168] The controller calculates an amount of damage to the working device based on strain data detected by the plurality of strain sensors, and displays a lifespan of the working device predicted based on a cumulative value of the amount of damage on the display device.

[0169] (Note 10)

[0170] The system including the working machine according to Supplementary Note 5, wherein:

[0171] The controller outputs an alarm signal when the estimated stress is greater than a predetermined threshold value.

[0172] (Note 11)

[0173] A system comprising a work machine, wherein:

[0174] The system has:

[0175] The main body of the operating machinery;

[0176] A working device installed on the working machine body;

[0177] a plurality of strain sensors disposed along a portion of the working device intersecting the imaginary plane;

[0178] display device; and

[0179] A controller that determines a load pattern of the working device based on strain data detected by the plurality of strain sensors and estimates stress at any portion of the working device. When the estimated stress is greater than a predetermined threshold, the controller displays the load pattern and the portion of the working device at which the estimated stress is greater than the predetermined threshold on the display device.

[0180] (Note 12)

[0181] The system including the working machine according to any one of Supplementary Notes 1 to 11, wherein:

[0182] The plurality of strain sensors respectively include a strain gauge and a bridge circuit.

[0183] The strain gauge and the bridge circuit are formed of semiconductor devices.

[0184] (Note 13)

[0185] A method for estimating a load state of a working machine is provided, wherein:

[0186] The load state estimation method of the working machine includes:

[0187] a step of disposing a plurality of strain sensors along a portion of the working device intersecting the imaginary plane; and

[0188] The step of estimating a load state of the working device based on strain data detected by the plurality of strain sensors.

[0189] (Note 14)

[0190] A method for estimating a load state of a working machine is provided, wherein:

[0191] The load state estimation method of the working machine includes:

[0192] The step of disposing a plurality of strain sensors at at least four locations of the working device; and

[0193] The step of estimating a load state of the working device based on the strain data of the at least four locations detected by the plurality of strain sensors.

[0194] (Note 15)

[0195] A method for estimating a load state of a working machine includes a working machine body, a working device mounted on the working machine body, and a display device, wherein:

[0196] The load state estimation method of the working machine includes:

[0197] a step of disposing a plurality of strain sensors along a portion of the working device intersecting the imaginary plane;

[0198] a step of determining a load pattern of the working device based on strain data detected by the plurality of strain sensors;

[0199] a step of estimating stress at any portion of the working device; and

[0200] The step of displaying, on the display device, a load pattern and a portion of the working device when the estimated stress is greater than a predetermined threshold value.

[0201] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The scope of the present invention is indicated by the claims rather than the above description, and includes all modifications within the meaning and scope equivalent to the claims.

[0202] Description of reference numerals:

[0203] 1. Machine body; 2. Work mechanism; 3. Swinging structure; 4. Operator's cab; 4. Operator's seat; 5. Traveling structure; 5. Crawler track; 5. Travel motor; 6. Boom; 6.a, 6.b Horizontal plate; 6.c, 6.d Vertical plate; 7. Arm; 8. Bucket; 9.a Boom cylinder; 9.b Arm cylinder; 9.c Bucket cylinder; 10. Hydraulic excavator; 11.a, 11.b, 11.c, 11.d Strain sensor; 12. Strain gauge; 13. Bridge circuit; 14. Strain amplifier; 20. Controller; 21. Strain acquisition unit; 22. Load state estimation unit; 22a. Stress estimation unit; 22b. Load pattern determination unit; 23. Damage calculation unit; 24. Life prediction unit; 25. Storage unit; 26. Output device control unit; 27. Stress determination unit; 30. Output device; 31. Display unit; 32. Notification unit; AT arm top pin; BCH Boom cylinder mounting hole; BF boom base pin; BFH boom base pin hole; BT boom top pin; BTH boom top pin hole; C center; C1, C2, C3, C4 corners; CO1, CO2, CO3, CO4 corners; CP1, CP2, CP3, CP4 connections.

Claims

1. A system comprising a work machine, wherein: The system has: The main body of the operating machinery; A working device installed on the working machine body; a plurality of strain sensors disposed along a portion of the working device intersecting the imaginary plane; as well as A controller estimates a load state of the working device based on strain data detected by the plurality of strain sensors.

2. A system comprising a working machine, wherein: The system has: The main body of the operating machinery; A working device installed on the working machine body; a plurality of strain sensors disposed at at least four locations of the working device; as well as A controller estimates a load state of the working device based on the strain data of the at least four locations detected by the plurality of strain sensors.

3. The system comprising a working machine according to claim 1 or 2, wherein: The working device is a boom or a dipper arm, The load state of the working device includes the load mode of the working device, The load pattern includes at least excavation.

4. The system comprising a working machine according to claim 1 or 2, wherein: The working machine includes a rotating body, The load state of the working device includes the load mode of the working device, The load mode includes at least lateral compression and extensional lateral compression.

5. The system including the working machine according to claim 1 or 2, wherein: The working device is a boom or a dipper arm, The load state of the working device includes the stress of the working device, The controller estimates stress at an arbitrary portion of the working device based on strain data detected by the plurality of strain sensors.

6. The system comprising a work machine according to claim 1, wherein: The working device is a boom or a dipper arm, The plurality of strain sensors are disposed at at least three corners of the working device.

7. The system comprising a work machine according to claim 2, wherein: The working device is a boom or a dipper arm, The plurality of strain sensors are arranged on at least two different surfaces.

8. The system comprising a work machine according to claim 1, wherein: The working device is a boom or a dipper arm, The imaginary plane is located closer to the working machine body than the center in the longitudinal direction of the working device.

9. The system including a working machine according to claim 1 or 2, wherein: The system further comprises a display device, The controller calculates an amount of damage to the working device based on strain data detected by the plurality of strain sensors, and displays a lifespan of the working device predicted based on a cumulative value of the amount of damage on the display device.

10. The system comprising a work machine according to claim 5, wherein: The controller outputs an alarm signal when the estimated stress is greater than a predetermined threshold value.

11. A system comprising a work machine, wherein: The system has: The main body of the operating machinery; A working device installed on the working machine body; a plurality of strain sensors disposed along a portion of the working device intersecting the imaginary plane; display device; as well as A controller that determines a load pattern of the working device based on strain data detected by the plurality of strain sensors and estimates stress at any portion of the working device. When the estimated stress is greater than a predetermined threshold, the controller displays the load pattern and the portion of the working device at which the estimated stress is greater than the predetermined threshold on the display device.

12. The system comprising a working machine according to any one of claims 1, 2 and 11, wherein: The plurality of strain sensors respectively include a strain gauge and a bridge circuit. The strain gauge and the bridge circuit are formed of semiconductor devices.

13. A method for estimating a load state of a working machine, comprising: a working machine body and a working device mounted on the working machine body; The load state estimation method of the working machine includes: a step of disposing a plurality of strain sensors along a portion of the working device intersecting the imaginary plane; and The step of estimating a load state of the working device based on strain data detected by the plurality of strain sensors.

14. A method for estimating a load state of a working machine, comprising: a working machine body and a working device mounted on the working machine body; The load state estimation method of the working machine includes: The step of disposing a plurality of strain sensors at at least four locations of the working device; and A step of estimating a load state of the working device based on the strain data of the at least four locations detected by the plurality of strain sensors.

15. A method for estimating a load state of a working machine, comprising a working machine body, a working device mounted on the working machine body, and a display device, wherein: The load state estimation method of the working machine includes: a step of disposing a plurality of strain sensors along a portion of the working device intersecting the imaginary plane; a step of determining a load pattern of the working device based on strain data detected by the plurality of strain sensors; a step of estimating stress at any portion of the working device; and The step of displaying, on the display device, a load pattern and a portion of the working device when the estimated stress is greater than a predetermined threshold value.

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