Processing apparatus, work machine, backlash amount estimation method, and backlash amount estimation program

Abstract

The present invention provides a processing device that can check changes in backlash amount regardless of the motor characteristics of the motor that inputs torque to the reduction gear. [Solution] The processing unit 100 performs the following: a first acquisition process to acquire the input phase, which is the rotational phase of the rotation input unit 261 that rotates based on the torque input to the reduction gear 220; a second acquisition process to acquire the output phase, which is the rotational phase of the rotation output unit 262 that rotates in the reduction gear 220 based on the torque from the rotation input unit 261; a third acquisition process to acquire the estimated phase based on the input phase and the reduction ratio; a fourth acquisition process to acquire the phase difference, which is the difference between the output phase and the estimated phase; and an output process to output the amount of backlash based on the phase difference.

Description

Technical Field

[0001] The present disclosure relates to a processing device, a work machine, a backlash amount estimation method, and a backlash amount estimation program.

Background Art

[0002] Patent Document 1 discloses a robot diagnosis method for estimating a failure in a transmission device of a robot drive system. Examples of the failure in the transmission device of the robot drive system include an increase in the backlash amount in a speed reducer.

[0003] In the diagnosis method of Patent Document 1, a backlash time during which the output torque is substantially zero is acquired. Further, in the diagnosis method of Patent Document 1, a torque difference between the actual drive torque and the output torque is acquired. Thereafter, failure diagnosis is performed by comparing the backlash time and the torque difference with profile data.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0005] In the diagnosis method of Patent Document 1, it is necessary to prepare profile data corresponding to motor characteristics in advance. Creating such profile data for each motor characteristic is labor-intensive.

Means for Solving the Problems

[0006] A processing device for solving the above problems performs the following: a first acquisition process for acquiring the input phase, which is the rotational phase of a rotating input section that rotates based on the torque input to the reduction gear; a second acquisition process for acquiring the output phase, which is the rotational phase of a rotating output section that rotates based on the torque from the rotating input section to the reduction gear; a third acquisition process for acquiring an estimated phase based on either the input phase or the output phase, and the reduction ratio, which is the ratio of the rotational speed of the rotating input section to the rotational speed of the rotating output section; a fourth acquisition process for acquiring a phase difference, which is the difference between the other of the input phase or the output phase and the estimated phase; and an output process for outputting a backlash amount based on the phase difference.

[0007] In the above configuration, the amount of backlash is output based on the input phase, output phase, and reduction ratio of the gearbox. Therefore, changes in the amount of backlash can be observed regardless of the motor characteristics of the motor that inputs torque to the gearbox.

[0008] In the processing apparatus, in the third acquisition process, the estimated phase may be obtained as the product of the amount of change in the input phase per unit time and the reduction ratio, and in the fourth acquisition process, the difference between the amount of change in the output phase per unit time and the estimated phase may be obtained as the phase difference.

[0009] In the processing device, if the amount of backlash is greater than a predetermined threshold, the output processing may output the amount of backlash based on the phase difference. In the processing apparatus, the rotation input unit may be the input shaft of the reduction gear to which torque from the motor is input, and the rotation output unit may be the output shaft of the reduction gear to which the torque of the reduction gear is output to the drive unit.

[0010] In the processing apparatus, the amount of backlash may be corrected based on a weight parameter relating to the weight of the drive unit. The work machine may also include a motor, a reduction gear to which torque from the motor is input, a drive unit to which the torque reduced by the reduction gear is input, and the processing unit described above.

[0011] The drive unit may be any of the following: a slewing bearing that rotatably connects the lower body and the upper body constituting the body of the work machine; a swing bracket that rotatably connects to the body; a boom that rotatably connects to the swing bracket; an arm that rotatably connects to the boom; and an attachment that rotatably connects to the arm.

[0012] A method for estimating the amount of backlash to solve the above problem is performed by a computer to perform the following: a first process in which a computer obtains the input phase, which is the rotational phase of a rotating input part that rotates based on the torque input to the reduction gear; a second process in which a computer obtains the output phase, which is the rotational phase of a rotating output part that rotates based on the torque from the rotating input part to the reduction gear; a third process in which a computer obtains an estimated phase based on either the input phase or the output phase and the reduction ratio, which is the ratio of the rotational speed of the rotating input part to the rotational speed of the rotating output part; a fourth process in which a computer obtains the phase difference, which is the difference between the other of the input phase or the output phase and the estimated phase; and a fifth process in which a computer outputs the amount of backlash based on the phase difference.

[0013] In the above configuration, the amount of backlash is output based on the input phase, output phase, and reduction ratio of the gearbox. Therefore, changes in the amount of backlash can be observed regardless of the motor characteristics of the motor that inputs torque to the gearbox.

[0014] A backlash amount estimation program for solving the above problem causes a computer to perform the following steps: a first step of causing a computer to acquire the input phase, which is the rotational phase of a rotating input part that rotates based on the torque input to the reduction gear; a second step of causing a computer to acquire the output phase, which is the rotational phase of a rotating output part that rotates based on the torque from the rotating input part to the reduction gear; a third step of causing a computer to acquire an estimated phase based on either the input phase or the output phase and the reduction ratio, which is the ratio of the rotational speed of the rotating input part to the rotational speed of the rotating output part; a fourth step of causing a computer to acquire the phase difference, which is the difference between the other of the input phase or the output phase and the estimated phase; and a fifth step of causing a computer to output a backlash amount based on the phase difference.

[0015] In the above configuration, the amount of backlash is output based on the input phase, output phase, and reduction ratio of the gearbox. Therefore, changes in the amount of backlash can be observed regardless of the motor characteristics of the motor that inputs torque to the gearbox. [Effects of the Invention]

[0016] With the above technical concept, it is possible to check the change in backlash amount regardless of the motor characteristics. [Brief explanation of the drawing]

[0017] [Figure 1] This is the first schematic diagram of an excavator, a type of construction machinery, as an example of working machinery. [Figure 2] Figure 1 is a second schematic diagram of the excavator. [Figure 3] This is a block diagram showing the torque transmission path in the excavator shown in Figure 1. [Figure 4] This is a block diagram showing a configuration for estimating the backlash amount of a gearbox in a work machine according to the first embodiment. [Figure 5] This is a flowchart showing the processing performed by the processing apparatus according to the first embodiment. [Figure 6] This is a flowchart showing the processing performed by the processing apparatus according to the second embodiment. [Figure 7] It is a schematic diagram of the working machine according to Configuration Example 1. [Figure 8] It is a schematic diagram of the conversion device in Figure 7. [Figure 9] It is a schematic diagram of the working machine according to Configuration Example 2. [Figure 10] It is a schematic diagram of the winch mechanism in Figure 9. [Modes for Carrying Out the Invention]

[0018] <First Embodiment> Hereinafter, one embodiment of the working machine will be described. The construction machine in the following description is an example of the working machine. For the purpose of simplifying and clarifying the description, the constituent elements shown in the drawings are not necessarily drawn to a constant scale.

[0019] <Overall Configuration> As shown in Figure 1, a shovel car 10 which is a construction machine includes a lower body 13 and an upper body 14. The upper body 14 is located on the side opposite to the ground G with respect to the lower body 13. In the present embodiment, the direction in which the upper body 14 is positioned as viewed from the lower body 13 is the upward direction, and the opposite direction is the downward direction. Further, a specific direction among the directions orthogonal to the upward direction is the forward direction, and the opposite direction is the rearward direction. Further, one of the directions orthogonal to both the upward direction and the forward direction is the left direction, and the other is the right direction. The forward direction and the rearward direction may be collectively referred to as the X direction. The left direction and the right direction may be collectively referred to as the Y direction. The upward direction and the downward direction may be collectively referred to as the Z direction.

[0020] The lower body 13 and the upper body 14 constitute the body of the excavator 10. The lower body 13 is, for example, rectangular parallelepiped. The upper body 14 comprises a main housing section 14A and a front housing section 14B. The main housing section 14A is, for example, rectangular parallelepiped. The interior of the main housing section 14A is a hollow storage space. The storage space houses various equipment for operating the excavator 10. The front housing section 14B is located on the front side of the main housing section 14A. The front housing section 14B is located approximately in the center of the main housing section 14A in the Y direction. The front housing section 14B is fixed to the front of the main housing section 14A. The front housing section 14B is, for example, a smaller rectangular parallelepiped than the main housing section 14A. The interior of the front housing section 14B is hollow. Although not shown in the figures, the upper body 14 includes a cabin in which an operator sits. The cabin is integrally fixed to the main housing section 14A. The upper body 14 is sometimes referred to as the upper rotating body.

[0021] As shown in Figure 1, the excavator 10 is equipped with a slewing bearing 18. The slewing bearing 18 is located between the lower body 13 and the upper body 14. In Figure 1, the vertical width of the slewing bearing 18 is exaggerated and shown as large with respect to the Z direction. As shown in Figure 2, the slewing bearing 18 comprises an annular inner ring 18A, an annular outer ring 18B, and a plurality of rolling elements. In Figure 2, the rolling elements are not shown. The outer diameter of the inner ring 18A is smaller than the inner diameter of the outer ring 18B. The slewing axis 10J, which is the central axis of the inner ring 18A, approximately coincides with the central axis of the outer ring 18B. The slewing axis 10J extends vertically, parallel to the Z direction, i.e., vertically, of the vehicle body. As shown in Figure 1, the slewing axis 10J passes vertically through both the upper body 14 and the lower body 13. The plurality of rolling elements are located between the inner ring 18A and the outer ring 18B. Multiple rolling elements support the inner ring 18A and the outer ring 18B so that they can rotate relative to each other. As a result, the outer ring 18B is rotatable relative to the inner ring 18A about the pivot axis 10J. The inner ring 18A is fixed to the lower body 13. The outer ring 18B is fixed to the main housing portion 14A of the upper body 14. That is, the upper body 14 is rotatable relative to the lower body 13 about the pivot axis 10J. It can also be said that the upper body 14 rotates relative to the lower body 13.

[0022] As shown in Figures 1 and 2, the excavator 10 is equipped with a pair of running gears 12. The pair of running gears 12 are located on the left and right sides of the lower body 13. Both running gears 12 are connected to the lower body 13. Each pair of running gears 12 includes a crawler for travel and an operating mechanism for rotating the crawler. The crawler is an endless belt shape. The crawler has openings on both the left and right sides. The underside of the crawler is in contact with the ground G. The excavator 10 moves as the crawler rotates. The running gears 12 and the lower body 13 are sometimes collectively referred to as the lower running gear.

[0023] As shown in Figures 1 and 2, the excavator 10 is equipped with a swing bracket 17. The swing bracket 17 is located on the front side of the main housing portion 14A of the upper body 14. The swing bracket 17 comprises a first swing wall 17A and a second swing wall 17B. The first swing wall 17A is located on the upper surface of the front housing portion 14B of the upper body 14. The first swing wall 17A is, for example, disc-shaped. The first swing wall 17A is connected to the front housing portion 14B. The first swing wall 17A is rotatable about the swing axis 61J relative to the front housing portion 14B. The swing axis 61J is approximately parallel to the pivot axis 10J. Details of the swing axis 61J will be described later. The second swing wall 17B protrudes upward from the upper surface of the first swing wall 17A. The second swing wall 17B is, for example, rectangular plate-shaped.

[0024] <Work Attachment> As shown in Figure 1, the excavator 10 is equipped with a work attachment 20. The work attachment 20 comprises a boom 21, an arm 23, and a bucket 25.

[0025] As shown in Figure 1, the boom 21 is located on the front side relative to the main housing portion 14A of the upper body 14. The boom 21 is a long, plate-like or columnar shape. As shown in Figure 2, the first longitudinal end 21A of the boom 21 is aligned with the second swing wall 17B of the swing bracket 17 in the direction along the first axis 31J. The first axis 31J is a virtual axis that is approximately perpendicular to the swing axis 61J. Details of the first axis 31J will be described later. The first end 21A of the boom 21 is rotatably connected to the second swing wall 17B.

[0026] As shown in Figure 1, the arm 23 extends from the second end 21B of the boom 21, opposite to the first end 21A. The arm 23 is a long, plate-like or columnar shape. As shown in Figure 2, the longitudinal first end 23A of the arm 23 is aligned with the second end 21B of the boom 21 in the direction along the second axis 41J. The second axis 41J is a virtual axis that is approximately parallel to the first axis 31J. Details of the second axis 41J will be described later. The first end 23A of the arm 23 is rotatably connected to the second end 21B of the boom 21.

[0027] As shown in Figure 1, the bucket 25 is located near the second end 23B of the arm 23, opposite to the first end 23A. The bucket 25 comprises a bucket body 26, a plurality of claws 27, and a bucket connecting wall 28. The bucket body 26 is box-shaped. That is, as shown in Figure 2, the bucket body 26 has an opening 26A. The claws 27 protrude from one side of the rectangular opening edge of the bucket body 26. The bucket connecting wall 28 protrudes from the outer wall of the bucket body 26, on the opposite side of the opening 26A from the claws 27. As shown in Figure 2, the bucket connecting wall 28 is aligned with the second end 23B of the arm 23 in the direction along the third axis 51J. The third axis 51J is a virtual axis that is substantially parallel to both the first axis 31J and the second axis 41J. Details of the third axis 51J will be described later. The bucket connecting wall 28 is rotatably connected to the second end 23B of the arm 23.

[0028] <Actuator> As shown in Figure 3, the excavator 10 is equipped with a first actuator 31, a second actuator 41, and a third actuator 51. The excavator 10 is also equipped with a first inverter 35, a second inverter 45, a third inverter 55, and a battery 19. Although not shown in the figure, the first inverter 35, the second inverter 45, the third inverter 55, and the battery 19 are housed in the main housing 14A of the upper body 14.

[0029] As shown in Figure 2, the first actuator 31 is located between the second swing wall 17B of the swing bracket 17 and the first end 21A of the boom 21. As shown in Figure 3, the first actuator 31 comprises a first electric motor 32 and a first reduction gear 33. The first electric motor 32 is a three-phase AC motor. The first electric motor 32 is electrically connected to the battery 19 via a first inverter 35. The first electric motor 32 comprises a housing 32A and an output shaft 32B rotatable relative to the housing 32A. The housing 32A is attached to the second swing wall 17B of the swing bracket 17. The output shaft 32B protrudes from the inside to the outside of the housing 32A. The output shaft 32B is cylindrical. The output shaft 32B is rotatable relative to the housing 32A about its own central axis, the first axis 31J. That is, the output shaft 32B outputs torque about the first axis 31J. The output shaft 32B is rotatable in both forward and reverse directions around the first axis 31J. As shown in Figure 2, the first axis 31J passes through both the second swing wall 17B of the swing bracket 17 and the first end 21A of the boom 21.

[0030] As shown in Figure 3, the first reduction gear 33 comprises a housing 33A, a reduction mechanism 33B, and an output member 33C. The housing 33A is attached to the housing 32A of the first electric motor 32. The reduction mechanism 33B is located inside the housing 33A. Torque is input to the reduction mechanism 33B from the output shaft 32B of the first electric motor 32. The reduction mechanism 33B amplifies the torque from the first electric motor 32 at a predetermined ratio and outputs it to the output member 33C. The reduction mechanism 33B is, for example, an eccentric oscillating gear type or a planetary gear type. The output member 33C is cylindrical. The central axis of the output member 33C is approximately coincident with the first axis 31J. The output member 33C is rotatable relative to the housing 33A. The output member 33C rotates about the first axis 31J in accordance with the rotation of the output shaft 32B of the first electric motor 32. The output member 33C is attached to the first end 21A of the boom 21. That is, the output member 33C inputs torque to the boom 21 around the first axis 31J. The boom 21 receives this torque and rotates around the first axis 31J.

[0031] As shown in Figure 2, the second actuator 41 is located between the second end 21B of the boom 21 and the first end 23A of the arm 23. The configuration of the second actuator 41 is basically the same as that of the first actuator 31, except for details such as dimensions, reduction ratio, and output. Therefore, the configuration of the second actuator 41 will be briefly described below.

[0032] As shown in Figure 3, the second actuator 41 comprises a second electric motor 42 and a second reduction gear 43. The second electric motor 42 is electrically connected to the battery 19 via a second inverter 45. The housing 42A of the second electric motor 42 is attached to the second end 21B of the boom 21. The output shaft 42B of the second electric motor 42 outputs torque around its own central axis, the second axis 41J. As shown in Figure 2, the second axis 41J passes through both the second end 21B of the boom 21 and the first end 23A of the arm 23. The output member 43C of the second reduction gear 43 is attached to the first end 23A of the arm 23. As shown in Figure 3, the output member 43C outputs torque around the second axis 41J. The arm 23 rotates around the second axis 41J in response to the torque from the output member 43C. Furthermore, the functions of the housing 43A and reduction mechanism 43B of the second reduction gear 43 are the same as those of the housing 33A and reduction mechanism 33B of the first reduction gear 33.

[0033] As shown in Figure 2, the third actuator 51 is located between the second end 23B of the arm 23 and the bucket connecting wall 28 of the bucket 25. The configuration of the third actuator 51 is basically the same as that of the first actuator 31, except for details such as dimensions, reduction ratio, and output. Therefore, the configuration of the third actuator 51 will be briefly described below.

[0034] As shown in Figure 3, the third actuator 51 comprises a third electric motor 52 and a third reduction gear 53. The third electric motor 52 is electrically connected to the battery 19 via a third inverter 55. The housing 52A of the third electric motor 52 is attached to the second end 23B of the arm 23. The output shaft 52B of the third electric motor 52 outputs torque around its own central axis, the third axis 51J. As shown in Figure 2, the third axis 51J passes through both the second end 23B of the arm 23 and the bucket connecting wall 28. The output member 53C of the third reduction gear 53 is attached to the bucket connecting wall 28. As shown in Figure 3, the output member 53C outputs torque around the third axis 51J. The bucket 25 rotates around the third axis 51J in response to the torque from the output member 53C. Furthermore, the functions of the housing 53A and reduction mechanism 53B of the third reduction gear 53 are the same as those of the housing 33A and reduction mechanism 33B of the first reduction gear 33.

[0035] As shown in Figure 3, the excavator 10 is equipped with a swing actuator 61 and a fourth inverter 65. As shown in Figure 1, the swing actuator 61 is housed in the front part 14B of the housing of the upper body 14. Although not shown in the figure, the fourth inverter 65 is housed in the main part 14A of the housing of the upper body 14. The configuration of the swing actuator 61 is basically the same as that of the first actuator 31, except for details such as dimensions, reduction ratio, and output. Therefore, the configuration of the swing actuator 61 will be briefly described below.

[0036] As shown in Figure 3, the swing actuator 61 comprises a fourth electric motor 62 and a fourth reduction gear 63. The fourth electric motor 62 is electrically connected to the battery 19 via a fourth inverter 65. The housing 62A of the fourth electric motor 62 is attached to the front part 14B of the housing of the upper body 14. The output shaft 62B of the fourth electric motor 62 outputs torque around its own central axis, the swing axis 61J. The output member 63C of the fourth reduction gear 63 is attached to the first swing wall 17A of the swing bracket 17. The output member 63C outputs torque around the swing axis 61J. The swing bracket 17 rotates around the swing axis 61J in response to the torque from the output member 63C. The functions of the housing 63A and reduction mechanism 63B of the fourth reduction gear 63 are the same as those of the housing 33A and reduction mechanism 33B of the first reduction gear 33.

[0037] As shown in Figure 3, the excavator 10 is equipped with a slewing actuator 71 and a fifth inverter 75. The slewing actuator 71 and the fifth inverter 75 are housed in the main housing 14A of the upper body 14. The configuration of the slewing actuator 71 is basically the same as that of the first actuator 31, except for details such as dimensions, reduction ratio, and output. Therefore, the configuration of the slewing actuator 71 will be briefly described below.

[0038] As shown in Figure 3, the slewing actuator 71 comprises a fifth electric motor 72 and a fifth reduction gear 73. The fifth electric motor 72 is electrically connected to the battery 19 via a fifth inverter 75. The housing 72A of the fifth electric motor 72 is attached to the main housing portion 14A of the upper body 14. The output shaft 72B of the fifth electric motor 72 outputs torque centered on the slewing axis 10J. Multiple teeth are formed on the output member 73C of the fifth reduction gear 73. These teeth mesh with the teeth formed on the inner ring 18A of the slewing bearing 18. The output member 73C outputs torque coaxial with the fifth electric motor 72. In response to this torque, the upper body 14 rotates with respect to the inner ring 18A and, consequently, the lower body 13, together with the housing 72A of the fifth electric motor 72. In other words, the slewing actuator 71 causes the upper body 14 to rotate relative to the lower body 13. Furthermore, the functions of the housing 73A and reduction mechanism 73B of the fifth reduction gear 73 are the same as those of the housing 33A and reduction mechanism 33B of the first reduction gear 33.

[0039] <Sensor> As shown in Figure 3, the excavator 10 is equipped with a first angle sensor 38, a second angle sensor 48, a third angle sensor 58, and a fourth angle sensor 68. The first angle sensor 38 detects the angular position 38S of the first electric motor 32. The angular position 38S of the first electric motor 32 is, strictly speaking, the angular position of the output shaft 32B of the first electric motor 32. For the other electric motors, the output shaft is omitted from the description of the angular position. The second angle sensor 48 detects the angular position 48S of the second electric motor 42. The third angle sensor 58 detects the angular position 58S of the third electric motor 52. The fourth angle sensor 68 detects the angular position 68S of the fourth electric motor 62. The angular position detected by each angle sensor is a value in the range of "0 degrees to 360 degrees", with a predetermined reference position of "0 degrees". In other words, each angular position represents the absolute angle of the respective electric motor. Each angle sensor repeatedly outputs a signal corresponding to the information it has detected to the processing unit 100, which will be described later.

[0040] Although not shown in the diagram, the excavator 10 is equipped with various sensors necessary for its operation, in addition to the sensors mentioned above. For example, the excavator 10 is equipped with sensors that detect the current flowing through each electric motor, and sensors that detect the temperature of the battery 19.

[0041] <Processing device> As shown in Figure 3, the excavator 10 is equipped with a processing unit 100. The processing unit 100 is a computer equipped with a processing circuit. The processing circuit includes a CPU 101 and a memory 102. The memory 102 includes three types: RAM, ROM, and electrically rewritable nonvolatile memory. In this embodiment, these three types are collectively referred to as memory 102. The memory 102 pre-stores various control programs 102A that describe the processing to be executed by the CPU 101. The memory 102 pre-stores various data 102B necessary for the CPU 101 to execute the control programs 102A. The processing circuit includes a communication circuit for wireless communication with the outside.

[0042] <Estimation of backlash amount> As described above, the excavator 10 is equipped with multiple electric motors, multiple reduction gears, and multiple drive units operated by torque from the reduction gears. Hereafter, when there are common characteristics among the multiple electric motors and there is no need to distinguish between them, they will be collectively referred to as motors 210. Similarly, when necessary, the reduction gears 220 and drive units 230 will be collectively referred to as such.

[0043] Incidentally, backlash occurs in the reduction gear 220. The amount of backlash in the reduction gear 220 increases as components such as gears, shafts, pins, and cases that make up the reduction gear 220 wear down or deform. In this embodiment, backlash is the delay between the rotation of the rotation output unit 262 and the rotation of the rotation input unit 261, which will be described later. The amount of backlash is defined as the difference between the rotation phase of the rotation input unit 261 and the rotation phase of the rotation output unit 262, or the time from when the rotation input unit 261 starts rotating until when the rotation output unit 262 starts rotating. Below, we will explain how the processing unit 100 estimates the amount of backlash in the reduction gear 220 in the work machine.

[0044] As shown in Figure 4, the excavator 10, as a work machine, is equipped with a motor 210, a reduction gear 220, and a drive unit 230. Furthermore, as described above, the excavator 10 is equipped with a processing unit 100.

[0045] Motor 210 outputs torque to the reduction gear 220. As shown in Figure 3, motor 210 is, for example, one of the first electric motor 32, the second electric motor 42, the third electric motor 52, the fourth electric motor 62, and the fifth electric motor 72.

[0046] The reduction gear 220 receives torque from the motor 210. The reduction gear 220 reduces the rotational torque of the motor 210. As shown in Figure 3, the reduction gear 220 is one of the first reduction gear 33, the second reduction gear 43, the third reduction gear 53, the fourth reduction gear 63, and the fifth reduction gear 73. If the motor 210 is the first electric motor 32, the reduction gear 220 is the first reduction gear 33. If the motor 210 is the second electric motor 42, the reduction gear 220 is the second reduction gear 43. If the motor 210 is the third electric motor 52, the reduction gear 220 is the third reduction gear 53. If the motor 210 is the fourth electric motor 62, the reduction gear 220 is the fourth reduction gear 63. If the motor 210 is the fifth electric motor 72, the reduction gear 220 is the fifth reduction gear 73.

[0047] As shown in Figure 4, the gearbox 220 has an input shaft 221, a reduction unit 222, and an output shaft 223. Torque from the motor 210 is input to the input shaft 221. The torque input to the input shaft 221 is input to the reduction unit 222. The reduction unit 222 reduces the rotational speed of the torque input from the input shaft 221. The reduction unit 222 outputs the torque with reduced rotational speed to the output shaft 223. The output shaft 223 outputs the torque of the gearbox 220 to the drive unit 230.

[0048] For example, if the reduction gear 220 is the first reduction gear 33, the input shaft 221 is the shaft connected to the output shaft 32B of the first electric motor 32 within the first reduction gear 33. The torque of the first electric motor 32 is input to the reduction unit 222 via the shaft that is the input shaft 221. The shaft that is the input shaft 221 may also be part of the reduction unit 222. If the reduction gear 220 is the first reduction gear 33, the reduction unit 222 is the reduction mechanism 33B, and the output shaft 223 is the output member 33C. The same correspondence between the reduction gear 220 and the first reduction gear 33 applies when the reduction gear 220 is the second reduction gear 43, the third reduction gear 53, the fourth reduction gear 63, or the fifth reduction gear 73.

[0049] The drive unit 230 receives torque reduced by the reduction gear 220. The drive unit 230 is driven to rotate by the torque reduced by the reduction gear 220. The drive unit 230 is, for example, one of the swing bracket 17, slewing bearing 18, boom 21, arm 23, and attachment. The swing bracket 17 is rotatably connected to the body of the work machine. The slewing bearing 18 rotatably connects the lower body 13 and the upper body 14 that constitute the body of the work machine. The boom 21 is rotatably connected to the swing bracket 17. The arm 23 is rotatably connected to the boom 21. The bucket 25 is rotatably connected to the arm 23. The attachment is a member rotatably connected to the arm 23. In this embodiment, the attachment is the bucket 25.

[0050] If motor 210 is the first electric motor 32, the drive unit 230 is the boom 21. If motor 210 is the second electric motor 42, the drive unit 230 is the arm 23. If motor 210 is the third electric motor 52, the drive unit 230 is the bucket 25 as an attachment. If motor 210 is the fourth electric motor 62, the drive unit 230 is the swing bracket 17. If motor 210 is the fifth electric motor 72, the drive unit 230 is the slewing bearing 18.

[0051] The work machine includes an input encoder 251 and an output encoder 252. The input encoder 251 acquires the input phase. The input phase is the rotation phase of the rotation input section 261. The rotation input section 261 is a part that rotates based on the torque input to the reduction gear 220. In this embodiment, the rotation input section 261 is the input shaft 221 of the reduction gear 220. The input encoder 251 is, for example, an angle sensor. For example, if the reduction gear 220 is a first reduction gear 33, the input encoder 251 acquires the angular position of the shaft connected to the output shaft 32B of the first electric motor 32 of the first reduction gear 33 as the input phase. In this case, the input encoder 251 may be a first angle sensor 38. The first angle sensor 38 as the input encoder 251 may acquire the angular position of the output shaft 32B of the first electric motor 32 as the input phase. The input encoder 251 outputs the acquired input phase to the processing unit 100.

[0052] The output encoder 252 acquires the output phase. The output phase is the rotation phase of the rotary output unit 262. The rotary output unit 262 is the part of the reduction gear 220 that rotates based on the torque from the rotary input unit 261. In this embodiment, the rotary output unit 262 is the output shaft 223 of the reduction gear 220. The output encoder 252 is, for example, an angle sensor. For example, if the reduction gear 220 is the first reduction gear 33, the output encoder 252 acquires the angular position of the output member 33C of the first reduction gear 33, which is the output shaft 223, as the output phase. The output encoder 252 outputs the acquired output phase to the processing unit 100.

[0053] The work machine is equipped with an output device 270. The output device 270 outputs information about the work machine. The information about the work machine is, for example, information about the backlash of the reduction gear 220. Note that the information about backlash is not limited to the amount of backlash itself, but may also indicate a determination result showing whether the amount of backlash is within an acceptable range or an unacceptable range. The output device 270 is, for example, a display that can be viewed by the operator. The display, which is the output device 270, is located in the cabin of the excavator 10.

[0054] <Processing flow by the processing unit> The processing flow by the processing unit 100 will be explained with reference to Figure 5. The processing in Figure 5 is executed at predetermined intervals when the drive unit 230 is driven by the torque output by the motor 210.

[0055] The processing unit 100 executes the first acquisition process P11, the second acquisition process P12, the third acquisition process P13, the fourth acquisition process P14, the output process P15, and the determination process P16. In other words, the processing unit 100, acting as a computer, executes the first acquisition process P11, the second acquisition process P12, the third acquisition process P13, the fourth acquisition process P14, the output process P15, and the determination process P16 to realize a series of backlash amount estimation methods. Furthermore, in the processing unit 100 as the processing unit 100, the control program 102A stored in the memory 102 includes the execution programs for the first acquisition process P11, the second acquisition process P12, the third acquisition process P13, the fourth acquisition process P14, the output process P15, and the determination process P16, i.e., the backlash amount estimation program.

[0056] The first acquisition process P11 is the process of acquiring the input phase. The process in step S11 corresponds to the first acquisition process P11. The processing unit 100 acquires the input phase from the input side encoder 251. For example, the processing unit 100 takes the state in which the rotation input unit 261 is at a specific rotation position as the reference rotation position, and acquires the difference in angular position with respect to that reference rotation position as the input phase in the form of a value of 0 degrees or more and less than 360. After acquiring the input phase, the processing unit 100 proceeds to step S12.

[0057] The second acquisition process P12 is the process of acquiring the output phase. The process in step S12 corresponds to the second acquisition process P12. The processing unit 100 acquires the output phase from the output side encoder 252. For example, the processing unit 100 takes the state in which the rotation output unit 262 is at a specific rotation position as the reference rotation position, and acquires the difference in angular position with respect to that reference rotation position as the output phase in the form of a value of 0 degrees or more and less than 360. After acquiring the output phase, the processing unit 100 proceeds to step S13.

[0058] The third acquisition process P13 is a process that acquires an estimated phase based on the input phase and the reduction ratio. The process in step S13 corresponds to the third acquisition process P13. The reduction ratio is the ratio of the rotational speed of the rotational input unit 261 to the rotational speed of the rotational output unit 262. The reduction ratio is a value greater than 0 and less than 1. The reduction ratio is a value unique to each reduction gear 220. For example, if the reduction gear 220 is the first reduction gear 33, the reduction ratio is the reduction ratio of the first reduction gear 33. The processing unit 100 stores the reduction ratio between the rotational input unit 261 and the rotational output unit 262 in advance.

[0059] In this embodiment, the estimated phase acquired in the third acquisition process P13 is an estimated value of the output phase estimated based on the input phase. The processing unit 100 acquires the estimated phase by calculating the estimated phase based on the input phase and the reduction ratio.

[0060] Specifically, in the third acquisition process P13, the processing unit 100 acquires the estimated phase as the product of the input phase change per unit time and the reduction ratio. Based on the detection result of the input side encoder 251, the processing unit 100 acquires a predetermined input phase change per unit time. Then, based on the product of this input phase change and the reduction ratio, it calculates the estimated change in the output phase of the rotation output unit 262 per unit time as the estimated phase. In this embodiment, the angular position of the rotation output unit 262 at the beginning of the unit time is set to zero, and the angular position of the rotation output unit 262 at the end of the unit time is calculated as the estimated phase. Note that the unit time here may be the control cycle in which the series of processes shown in Figure 5 are repeated. After acquiring the estimated phase, the processing unit 100 proceeds to step S14.

[0061] The fourth acquisition process P14 is a process for acquiring the phase difference. The process in step S14 corresponds to the fourth acquisition process P14. The phase difference is the difference between the output phase and the estimated phase. In the fourth acquisition process P14, the processing unit 100 acquires the difference between the amount of change in the output phase per unit time and the estimated phase as the phase difference. The phase difference is calculated, for example, by subtracting the amount of change in the output phase per unit time detected by the output-side encoder 252 from the estimated phase calculated in step S13. The difference between the output phase actually acquired from the rotation output unit 262 and the estimated phase, which is an estimated value of the output phase estimated based on the input phase, arises from the delay in the rotation of the rotation output unit 262 relative to the rotation of the rotation input unit 261.

[0062] The phase difference includes, for example, a first phase difference and a second phase difference. The first phase difference is the phase difference obtained when the motor 210 rotates in a first rotational direction. The second phase difference is the phase difference obtained when the motor 210 rotates in a second rotational direction. The second rotational direction is the opposite direction of rotation to the first rotational direction. When the motor 210 rotates in the first rotational direction, the values ​​of the input encoder 251 and the output encoder 252 increase. When the motor 210 rotates in the second rotational direction, the values ​​of the input encoder 251 and the output encoder 252 decrease.

[0063] The absolute value of the change in output phase based on the detected value of the output encoder 252 tends to be smaller than the absolute value of the estimated phase due to the effect of backlash. When the motor 210 rotates in the first rotational direction, the input phase and output phase become positive values. Therefore, when calculating the first phase difference by subtracting the change in output phase from the estimated phase, the first phase difference becomes a positive value. When the motor 210 rotates in the second rotational direction, the input phase and output phase become negative values. Therefore, when calculating the second phase difference by subtracting the change in output phase from the estimated phase, the second phase difference becomes a negative value.

[0064] If the motor 210 is rotating in the first rotational direction, the phase difference calculated in step S14 is the first phase difference. If the motor 210 is rotating in the second rotational direction, the phase difference calculated in step S14 is the second phase difference. After obtaining the phase difference, the processing unit 100 proceeds to step S15.

[0065] The determination process P16 is a process that determines whether or not to output a backlash amount based on the phase difference. Steps S15 to S21 correspond to the determination process P16. The processing unit 100 outputs a backlash amount based on the phase difference in output processing P15 when the backlash amount is greater than a predetermined threshold. The threshold is set to a value that determines, for example, when it is necessary to output the backlash amount. An example of when it is necessary to output the backlash amount is when the backlash amount of the reducer 220 reaches an amount that requires maintenance such as inspection, repair, or replacement of the work machine.

[0066] In step S15, the processing unit 100 determines whether the first phase difference is greater than the first value. The first value is the largest first phase difference among all the first phase differences calculated in step S14 of the processing shown in Figure 5 that have been performed in the past. At the time of factory shipment of the work machine, the first value is pre-set to a value of the first phase difference that is expected based on the structure of the reducer 220.

[0067] The processing unit 100 proceeds to step S16 if the first phase difference is greater than the first value. If the first phase difference is less than or equal to the first value, the processing unit 100 skips step S16 and proceeds to step S17. Also, if the first phase difference is not calculated in step S14, the processing unit 100 considers the first phase difference to be zero. Therefore, in this case, the processing unit 100 proceeds to step S17 without executing the process in step S15. Note that the case in which the first phase difference is not calculated is when the motor 210 is rotating in the second rotation direction.

[0068] In step S16, the processing unit 100 stores the first phase difference calculated in S14 as a new first value. After storing the first phase difference as a first value, the processing unit 100 proceeds to step S17.

[0069] In step S17, the processing unit 100 determines whether the second phase difference is smaller than the second value. The second value is the smallest second phase difference calculated in step S14 of the processing shown in Figure 5 that was performed in the past. At the time of factory shipment of the work machine, the second value is pre-set to a value of the second phase difference that is assumed based on the structure of the reducer 220.

[0070] The processing unit 100 proceeds to step S18 if the second phase difference is less than the second value. If the second phase difference is greater than or equal to the second value, the processing unit 100 skips step S18 and proceeds to step S19. Also, if the second phase difference is not calculated in step S14, the processing unit 100 considers the second phase difference to be zero. Therefore, in this case, the processing unit 100 proceeds to step S19 without executing the process in step S17. Note that the case where the second phase difference is not calculated is when the motor 210 is rotating in the first rotation direction.

[0071] In step S18, the processing unit 100 stores the second phase difference calculated in S14 as a new second value. After storing the second phase difference as a second value, the processing unit 100 proceeds to step S19.

[0072] In step S19, the processing unit 100 estimates the amount of backlash. Specifically, the processing unit 100 estimates the amount of backlash based on the difference between the first value and the second value. The difference between the first value and the second value is, that is, the difference between the largest first phase difference obtained up to the processing shown in Figure 5 and the smallest second phase difference. The processing unit 100 then converts the difference between the first value and the second value into the amount of backlash by applying it to a predetermined relationship, such as a relational expression or map. The amount of backlash is calculated as a distance, such as in millimeters or micrometers.

[0073] The value obtained by subtracting the second value from the first value reflects the combined amount of wear that occurs when the input shaft 221 rotates in the first rotational direction and the amount of wear that occurs when the input shaft 221 rotates in the second rotational direction. This takes into account that in a working machine, the input shaft 221 rotates in both directions with roughly the same frequency, not just in a specific direction.

[0074] In step S21, the processing unit 100 determines whether the amount of backlash is greater than a threshold. If the amount of backlash is greater than the threshold, the processing unit 100 proceeds to step S22. If the amount of backlash is less than or equal to the threshold, the processing unit 100 terminates the series of processes shown in Figure 5.

[0075] Output process P15 is a process that outputs the amount of backlash based on the phase difference. The process in step S22 corresponds to output process P15. For example, the processing unit 100 outputs the amount of backlash estimated in S19 to the output device 270. The output device 270, upon receiving the amount of backlash, displays that amount of backlash. The processing unit 100 causes the output device 270 to output the amount of backlash by outputting a signal related to the amount of backlash to the processing unit 100. After outputting the amount of backlash, the processing unit 100 terminates the process shown in Figure 5.

[0076] <Operation of this embodiment> In the configuration of the work machine, the processing unit 100 estimates the amount of backlash from the output of the input encoder 251, the output of the output encoder 252, and the reduction ratio of the reducer 220. Profile data for each characteristic of the motor 210 is not required for this series of backlash estimations.

[0077] <Effects of this embodiment> (1-1) The processing unit 100 obtains an estimated phase based on the input phase and reduction ratio. The processing unit 100 obtains a phase difference, which is the difference between the output phase and the estimated phase. The processing unit 100 outputs a backlash amount based on the phase difference. With this configuration, the processing unit 100 can check changes in the backlash amount without requiring detailed profile data representing the motor characteristics of the motor 210. As a result, the degree of deterioration of the reduction gear 220 can be easily determined based on the backlash amount.

[0078] (1-2) The processing unit 100 obtains the estimated phase as the product of the amount of change in the input phase per unit time and the reduction ratio. The processing unit 100 also obtains the difference between the amount of change in the output phase per unit time and the estimated phase as the phase difference. By obtaining the phase difference based on the change per unit time in this way, the phase difference can be easily calculated without, for example, converting it to the absolute angular position of the input shaft 221 and the output shaft 223.

[0079] (1-3) The processing unit 100 outputs a backlash amount based on the phase difference when the backlash amount is greater than a predetermined threshold. Since the phase difference is output when the backlash amount is greater than a predetermined threshold, the operator and manager of the work machine can understand that maintenance, etc., is required for the reduction gear 220.

[0080] (1-4) The rotary input unit 261 is the input shaft 221 of the reduction gear 220, which inputs torque from the motor 210 to the reduction gear 220. The rotary output unit 262 is the output shaft 223 of the reduction gear 220, which outputs the torque of the reduction gear 220 to the drive unit 230. The phase difference can be obtained by acquiring the rotational phase of the input shaft 221 and the rotational phase of the output shaft 223 in the reduction gear 220. With this configuration, sensors that are commonly attached to the work machine can be used as the input side encoder 251 and the output side encoder 252, thus preventing an increase in the number of parts required for the configuration to estimate the amount of backlash.

[0081] (1-5) The work machine comprises a motor 210, a gearbox 220, a drive unit 230, and a processing unit 100. The amount of backlash of the gearbox 220 serves as an indicator for the timing of maintenance such as inspection, servicing, and replacement of the work machine and the gearbox 220. In work machines such as construction machinery, the frequency of use and load vary greatly depending on the usage situation, so the lifespan and failure rate differ. The processing unit 100 allows for appropriate maintenance of the gearbox 220 based on the amount of backlash, thereby maintaining the work machine in good condition.

[0082] (1-6) The drive unit 230 is one of the swing bracket 17, the slewing bearing 18, the boom 21, the arm 23, and the attachment. With this configuration, the drive state of any of the swing bracket 17, the slewing bearing 18, the boom 21, the arm 23, and the attachment can be maintained in good condition in the work machine.

[0083] <Second Embodiment> The working machine of the second embodiment will be described with reference to Figures 4 and 6. In the second embodiment, the same configuration as in the first embodiment will be omitted or simplified in its description.

[0084] In addition to estimating the amount of backlash in the first embodiment, the processing unit 100 of this embodiment corrects the amount of backlash based on weight parameters related to the weight of the drive unit 230. The weight parameters include the weight or type of the drive unit 230. The weight parameters may also include the product name, part number, etc., of the drive unit 230. The processing unit 100 corrects the amount of backlash so that the larger the weight of the drive unit 230, the smaller the estimated amount of backlash with respect to the output phase.

[0085] As shown in Figure 6, the processing unit 100 of this embodiment performs a correction process P21. The correction process P21 is a process that corrects the amount of backlash that is ultimately output. The correction of the amount of backlash is performed, for example, by correcting at least one of the output phase, estimated phase, phase difference, and backlash amount. In this embodiment, a method of correcting the backlash value by correcting the output phase will be described.

[0086] The processing unit 100 corrects the estimated phase by, for example, correcting the output phase acquired in the second acquisition process P12 to a smaller value. Here, correcting the output phase to a smaller value means correcting the absolute value of the output phase to a smaller value. That is, when the motor 210 rotates in the first rotational direction, "correcting the output phase to a smaller value" means correcting the output phase, which is a positive value, to a smaller positive value. Also, when the motor 210 rotates in the second rotational direction, "correcting the output phase to a smaller value" means correcting the output phase, which is a negative value, to a larger negative value.

[0087] The processing unit 100 corrects the output phase to a smaller value by multiplying the output phase acquired in the second acquisition process P12 by a first correction value. This also corrects the estimated phase to a smaller value. The first correction value is predetermined to be greater than 0 and less than 1. The larger the weight of the drive unit 230, the smaller the value of the first correction value set to. The processing unit 100 stores a plurality of first correction values ​​corresponding to the weight of the drive unit 230.

[0088] By correcting the output phase to a smaller value, the phase difference, which is the estimated phase minus the change in output phase, becomes smaller. Here, when motor 210 rotates in the first rotational direction, "the phase difference becomes smaller" indicates that the positive value, the first phase difference, becomes smaller. When motor 210 rotates in the second rotational direction, "the phase difference becomes smaller" indicates that the negative value, the second phase difference, becomes larger. As the phase difference decreases, the amount of backlash based on the phase difference also decreases.

[0089] In this embodiment, at least a portion of the work attachment 20 of the excavator 10 as a work machine is replaceable. In one example, the bucket 25 of the work attachment 20 is replaceable. The work attachment 20 can, for example, select one from a plurality of buckets 25 with different weights. A correction value is set for each of the plurality of buckets 25 as a first correction value. The processing unit 100 acquires the correction value set for the attached bucket 25 as the first correction value. The weight or type of the attached bucket 25 is entered as a weight parameter by the worker when the bucket 25 is replaced. The processing unit 100 stores a plurality of first correction values ​​corresponding to each of the plurality of weight parameters.

[0090] The processing flow of the processing device 100 of this embodiment will be explained with reference to Figure 6. In the processing in Figure 6, step S31 is added to the processing in Figure 5. The explanation of processes common to the processing in Figure 6 will be omitted. Also, in Figure 6, the description from step S15 onwards is omitted. In the example in Figure 6, step S31 is added between step S12 and step S13.

[0091] In step S31, the processing unit 100 corrects the output phase. The processing unit 100 corrects the output phase by multiplying the output phase acquired in step S12 by a first correction value set based on the weight parameter. After correcting the output phase acquired in step S12, the processing unit 100 proceeds to step S13.

[0092] <Operation of this embodiment> The heavier the drive unit 230, the more torsion occurs in the output shaft 223 as the drive unit 230 rotates. This torsion causes a lag between the rotation of the output shaft 223 and the rotation of the input shaft 221. The heavier the drive unit 230, the larger the output phase and the larger the phase difference. This may lead to an overestimation of the backlash amount. Therefore, an appropriate backlash amount can be obtained by correcting the backlash amount based on the weight parameter of the drive unit 230.

[0093] <Effects of this embodiment> According to the second embodiment, in addition to the effects of the first embodiment, the following effects are achieved. (2-1) The processing unit 100 corrects the amount of backlash based on weight parameters related to the weight of the drive unit 230. Since the phase difference as the amount of backlash is corrected based on the weight parameters of the drive unit 230, an appropriate amount of backlash corresponding to the weight of the drive unit 230 can be obtained.

[0094] <Example of changes> The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0095] • Motor 210 may be an electric motor, an air motor, or a fluid motor that rotates due to the pressure of a fluid. In this embodiment, the rotation input section 261 is the input shaft 221 and the rotation output section 262 is the output shaft 223, but the configuration is not limited to this as long as the rotation output section 262 is located downstream of the rotation input section 261 in the reduction gear 220. The rotation input section 261 may be the first gear and the rotation output section 262 may be the second gear located downstream of the first gear. The rotation input section 261 may be the input shaft 221 and the rotation output section 262 may be the third gear located downstream of the input shaft 221. The rotation input section 261 may be the fourth gear located upstream of the output shaft 223 and the rotation output section 262 may be the output shaft 223. The first gear, second gear, third gear, and fourth gear are all components of the reduction gear 220.

[0096] In this embodiment, the processing unit 100 was described as a computer installed in the excavator 10, but the processing unit 100 may also be a maintenance computer connected to the excavator 10 when performing maintenance on the excavator 10.

[0097] The processing unit 100 may acquire an estimated phase based on the output phase and the reduction ratio in the third acquisition process P13. The processing unit 100 acquires the estimated phase as the value obtained by dividing the output phase by the reduction ratio in the third acquisition process P13. The processing unit 100 acquires the phase difference as the difference between the input phase and the estimated phase in the fourth acquisition process P14.

[0098] The judgment process P16 may be omitted. In this modified example, in the series of processes shown in Figure 5, after obtaining the phase difference in step S14, the amount of backlash based on the phase difference may be output in step S22. The calculation of the amount of backlash follows the example in step S19.

[0099] The processing unit 100 may calculate the amount of backlash from only one of the first or second values ​​in the fourth acquisition process P14. The backlash amount output in output processing P15 may be an indicator of the backlash amount. Examples of indicators of the backlash amount include values ​​that show the magnitude of the backlash amount in stages, and warning messages. Values ​​that show the magnitude of the backlash amount in stages may be set to values ​​such as a first value that shows a small amount of backlash and a second value that shows a large amount of backlash. The warning message is a message that informs the operator of the increase in backlash amount for maintenance of the reducer 220.

[0100] In a second embodiment, the processing unit 100 may obtain the weight of the bucket 25 based on the motor current of the motor 210 when the first operation is performed with the bucket 25 attached. The processing unit 100 stores the first motor current when the first operation is performed with the first bucket 25 attached. The processing unit 100 obtains the second motor current when the first operation is performed with the second bucket 25 attached. If the second bucket 25 is heavier than the first bucket 25, the second motor current will be greater than the first motor current. The processing unit 100 obtains the weight of the second bucket 25 as a weight parameter based on the difference between the first motor current and the second motor current.

[0101] In the second embodiment, the processing unit 100 may correct the amount of backlash to a smaller value by correcting the estimated phase to a smaller value. For example, the processing unit 100 corrects the phase difference to a smaller value by multiplying the estimated phase acquired in the third acquisition process P13 by a second correction value. The second correction value is a value greater than 0 and less than 1. The correction value is set to a smaller value as the weight of the drive unit 230 increases. The processing unit 100 stores a plurality of second correction values ​​corresponding to each of the plurality of weight parameters.

[0102] In the second embodiment, the processing unit 100 may correct the amount of backlash to a small value by correcting the phase difference to a small value. For example, the processing unit 100 corrects the phase difference to a small value by multiplying the phase difference acquired in the fourth acquisition process P14 by a third correction value. The third correction value is a value greater than 0 and less than 1. The third correction value is set to a small value as the weight of the drive unit 230 increases. The processing unit 100 stores a plurality of third correction values ​​corresponding to each of a plurality of weight parameters.

[0103] In the second embodiment, the processing unit 100 may correct the amount of backlash to a smaller value by multiplying the amount of backlash estimated in the determination process P16 by a fourth correction value. The fourth correction value is a value greater than 0 and less than 1. The fourth correction value is set to a smaller value as the weight of the drive unit 230 increases. The processing unit 100 stores a plurality of fourth correction values ​​corresponding to each of the plurality of weight parameters.

[0104] The torsion occurring in the reducer 220 may be estimated based on the phase difference. The processing unit 100 determines that the larger the phase difference, the greater the amount of torsion occurring in the reducer 220. For example, if the working machine is an excavator, the external torque may be estimated from the amount of torsion. The excavator first receives the excavation reaction force with the brake. The excavator releases the brake before the external torque exceeds the allowable brake torque, and receives the excavation reaction force with the motor torque.

[0105] In the second embodiment, the output phase correction may be performed by subtracting a correction value from the output phase. In the above embodiment, if multiple functions are provided in a distributed manner, some or all of those multiple functions may be consolidated and provided together. Conversely, if multiple functions are consolidated and provided together, some or all of those multiple functions may be distributed and provided together. Regardless of whether the functions are consolidated or distributed, it is sufficient that the device is configured to achieve the objective of the invention.

[0106] <Example of a work machine configuration 1> The working machines of each of the above embodiments may be configured as shown in Figures 7 and 8. In this configuration example, the configuration of the arm 23 as the first member 310, which will be described later, differs from that of each embodiment. Note that Figure 7 shows the portion of the upper body 14 of the excavator 10 that is located on the arm 23 side of the front part 14B of the housing, and other parts are omitted.

[0107] Japanese Patent Publication No. 2008-202364 discloses a hydraulic excavator. This hydraulic excavator comprises a boom extending from an upper slewing body, an arm extending from the boom, and a bucket attached to the arm.

[0108] In hydraulic excavators such as those disclosed in Japanese Patent Publication No. 2008-202364, making the length of components such as the boom and arm variable offers advantages such as expanding the working range and making the machine more compact when stored. For this reason, some work machines employ hydraulic cylinders to make the length of components such as the boom and arm variable. However, since the hydraulic cylinder is fixed to components such as the boom and arm, it is difficult to shorten components such as the boom 21 and arm 23 to a length shorter than the length of the hydraulic cylinder. Thus, there are limitations to the extension and retraction of telescopic structures that employ hydraulic cylinders.

[0109] In this configuration example, the rotational motion of the electric motor 330 is used as linear motion, making it possible to vary the lengths of components such as the boom 21 and arm 23. This overcomes the constraint that it is difficult to make components such as the boom 21 and arm 23 shorter than the length of the hydraulic cylinder.

[0110] As shown in Figure 7, the work machine in this modified example comprises a first member 310, a second member 320, an electric motor 330, and a conversion mechanism 340. The first member 310 is connected to the body of the work machine. The first member 310 is one selected from a boom 21, an arm 23, and a bucket 25. In this configuration example, the first member 310 is a boom 21 connected to the body of the excavator 10 via a swing bracket 17.

[0111] The second member 320 is rotatably connected to the first member 310. The second member 320 is one of the boom 21, arm 23, and bucket 25 that is different from the first member 310. In this example configuration, the second member 320 is the arm 23.

[0112] The electric motor 330 is the power source for the relative rotation of the first member 310 and the second member 320. The electric motor 330 is selected from the first electric motor 32, the second electric motor 42, and the third electric motor 52. In this configuration example, the second electric motor 42 rotates the arm 23, which is the second member 320, around the second axis 41J relative to the boom 21, which is the first member 310.

[0113] In the example shown in Figure 7, the conversion mechanism 340 is provided on the second member 320, which is the arm 23. The conversion mechanism 340 converts the rotational motion output by the electric motor 330 into linear motion and outputs it. In this embodiment, the second member 320, which is the arm 23, is extendable and retractable by the linear motion output by the conversion mechanism 340. Extending and retracting of the second member 320, which is the arm 23, means that the distance from the first end 23A to the second end 23B of the arm 23 increases or decreases. Alternatively, the conversion mechanism 340 may be provided on the first member 310, which is the boom 21, and the first member 310, which is the boom 21, may be extendable and retractable by the linear motion output by the conversion mechanism 340.

[0114] Figure 8 schematically shows the configuration around the conversion mechanism 340 of the second member 320. The work machine is equipped with a changeover gear device 350. The changeover gear device 350 can connect the electric motor 330 and the conversion mechanism 340. The changeover gear device 350 can switch the transmission state of the rotational motion of the electric motor 330 between a first transmission state and a second transmission state. In the first transmission state, the changeover gear device 350 connects the electric motor 330 and the conversion mechanism 340. In the first transmission state, the changeover gear device 350 transmits the rotational motion of the electric motor 330 to the conversion mechanism 340. In the second transmission state, the changeover gear device 350 connects the electric motor 330 and the second member 320. In the second transmission state, the changeover gear device 350 rotates the second member 320 relative to the first member 310 by the rotational motion of the electric motor 330.

[0115] The switching gear device 350 is configured as a reduction gear. The switching gear device 350 includes, for example, a second reduction gear 43 that transmits the rotational motion of a second electric motor 42, which is an electric motor 330, to the boom 21.

[0116] As shown in Figure 7, the second member 320 has a first portion 321 and a second portion 322. The first portion 321 includes the first end 21A of the second member 320 in the longitudinal direction. The second portion 322 includes the second end 21B of the second member 320 in the longitudinal direction.

[0117] In the example shown in Figure 8, the sides of the second member 320 are omitted to illustrate the inside of the second member 320. As shown in Figure 8, the conversion mechanism 340 includes, for example, an electric cylinder 341. The electric cylinder 341 is positioned along the longitudinal direction of the second member 320. One end of the electric cylinder 341 is connected to the first portion 321, and the other end of the electric cylinder 341 is connected to the second portion 322. As the electric cylinder 341 extends and retracts, the second portion 322 moves relative to the first portion 321 in the longitudinal direction of the second member 320. As the second portion 322 moves relative to the first portion 321, the second member 320 extends and retracts.

[0118] The electric cylinder 341 has a ball screw 342. The ball screw 342 extends and retracts due to the rotational motion output by the electric motor 330. The electric cylinder 341 extends and retracts as a result of the extension and retraction of the ball screw 342. The linear motion output by the conversion mechanism 340 is the extension and retraction of the electric cylinder 341. In Figure 8, two multi-stage ball screws 342 are used.

[0119] The conversion mechanism 340 may extend and retract by a structure other than the electric cylinder 341 having a ball screw 342. Examples of other conversion mechanisms 340 include a pantograph structure and a rack and pinion structure.

[0120] The conversion mechanism 340 has an outer casing 343. The outer casing 343 forms the outer surface of the second member 320. The outer casing 343 connects the first part 321 and the second part 322 of the second member 320. The outer casing 343 is box-shaped. The conversion mechanism 340 is housed in the internal space of the outer casing 343. The outer casing 343 has a telescopic structure. The telescopic structure can suppress the intrusion of dust into the interior of the outer casing 343. If the conversion mechanism 340 has resistance to dust and sufficient rigidity, the outer casing 343 may be omitted.

[0121] The second member 320 may have a communication device. The communication device is a wireless communication device. The communication device receives, for example, a first signal to extend the second member 320, or a second signal to retract the second member 320. Based on the received first or second signal, the second member 320 switches the transmission state of the switching gear device 350 to the first transmission state and outputs torque from the electric motor 330. This drives the conversion mechanism 340, causing the second member 320 to extend or retract. Since the extension and retraction of the second member 320 is performed by the communication device, there is no need to extend a communication line from the second member 320, thus simplifying the electrical configuration of the work machine.

[0122] <Example of a work machine configuration 2> As shown in Figures 9 and 10, in this configuration example, in the excavator 10, which is a construction machine, a winch mechanism 410 is located near the second end 23B of the arm 23, instead of a bucket 25. Note that Figure 9 shows the portion of the upper body 14 of the excavator 10 that is located on the arm 23 side of the front part 14B of the housing, and other parts are omitted.

[0123] Japanese Patent Publication No. 2014-213994 discloses a crane. This crane comprises a slewing body, a boom extending from the slewing body, and a hoisting drum. The crane also comprises a crane wire attached to the boom and a crane hook attached to the crane wire. Heavy objects are sometimes moved using cranes at work sites, but it may not be possible to install a crane in confined work sites.

[0124] In this configuration example, the excavator 10 is fitted with a winch mechanism 410 to add crane functionality. This allows heavy objects to be moved by the excavator 10 in confined work sites where a crane cannot be installed.

[0125] As shown in Figure 9, the construction machine comprises a boom 21, an arm 23, an electric motor 330, and a winch mechanism 410. The boom 21 is connected to the vehicle body. The arm 23 is rotatably connected to the boom 21. The electric motor 330 is mounted on the arm 23. In this example configuration, the electric motor 330 is, for example, a third electric motor 52.

[0126] The winch mechanism 410 shown in Figure 10 is attached to the output shaft of the electric motor 330 and can wind up or unwind the wire 414 as the output shaft of the electric motor 330 rotates. The output shaft of the third electric motor 52, which is the electric motor 330, is, for example, the output member 53C of the third reduction gear 53, which rotates due to the torque of the third electric motor 52, as shown in Figure 3.

[0127] The winch mechanism 410 includes a first pulley 411, a second pulley 412, a drum 413, and a wire 414. The first pulley 411 is mounted on the output shaft of the electric motor 330. The rotating shaft of the first pulley 411 is attached to the output shaft of the electric motor 330 by a coupling 416. The first pulley 411 rotates integrally with the output shaft of the electric motor 330. The second pulley 412 meshes with the first pulley 411. The second pulley 412 rotates integrally with the drum 413. The wire 414 is wound around the drum 413. A hook 415, for example, is attached to the end of the wire 414. The drum 413 is supported by a support member 417 on the second end 23B of the arm 23. The support member 417 is fixed to the arm 23 by a fixing member 418 such as a screw or bolt. The second pulley 412 is integrated with the drum 413.

[0128] The rotation of the output shaft of the electric motor 330 is transmitted to the drum 413 via the first pulley 411 and the second pulley 412. The rotation of the drum 413 causes the wire 414 to be wound up or unwound.

[0129] The winch mechanism 410 is detachable from the output shaft of the electric motor 330. By removing the coupling 416 from the output shaft of the electric motor 330, the first pulley 411 is removed from the output shaft of the electric motor 330. By loosening the fixing member 418, the support member 417 is removed from the arm 23. Along with the support member 417, the second pulley 412 and the drum 413 are removed from the arm 23.

[0130] If the winch mechanism 410 is removed from the output shaft of the electric motor 330, the bucket 25 is mounted on the output shaft of the electric motor 330 in its place. Since the winch mechanism 410 is powered by the torque of the electric motor 330, which powers the bucket 25, no additional power source other than the electric motor 330 is required.

[0131] This specification discloses the following technical concepts. [Note 1] A work machine comprising: a first member connected to a vehicle body; a second member rotatably connected to the first member; an electric motor which is a power source for the relative rotation of the first member and the second member; and a conversion mechanism which converts the rotational motion output by the electric motor into linear motion and outputs it, wherein one or more selected from the first member and the second member are extendable and retractable by the linear motion output by the conversion mechanism.

[0132] [Note 2] A construction machine comprising a boom connected to a vehicle body, an arm rotatably connected to the boom, an electric motor attached to the arm, and a winch mechanism attached to the output shaft of the electric motor, capable of winding up or unwinding a wire as the output shaft rotates, wherein the winch mechanism is detachable from the output shaft. [Explanation of symbols]

[0133] 100… Processing equipment 210...motor 220...Reducer 221...Input axis 223... Output shaft 230…Drive unit 261... Rotation input section 262... Rotation output section

Claims

1. A first acquisition process in which the input phase, which is the rotational phase of a rotating input part that rotates based on the torque input to the reduction gear, The reduction gear includes a second acquisition process for acquiring the output phase, which is the rotational phase of the rotational output unit that rotates based on the torque from the rotational input unit, A third acquisition process for acquiring an estimated phase based on either the input phase or the output phase, and a reduction ratio which is the ratio of the rotational speed of the rotational input unit to the rotational speed of the rotational output unit, A fourth acquisition process to acquire a phase difference, which is the difference between the other of the input phase and the output phase and the estimated phase, The output process outputs the amount of backlash based on the phase difference, and executes the following: Processing device.

2. In the third acquisition process, the estimated phase is obtained as the product of the amount of change in the input phase per unit time and the reduction ratio. In the fourth acquisition process, the difference between the amount of change in the output phase per unit time and the estimated phase is acquired as the phase difference. The apparatus according to claim 1.

3. If the amount of backlash is greater than a predetermined threshold, the output process outputs the amount of backlash based on the phase difference. The apparatus according to claim 1.

4. The aforementioned rotation input section is the input shaft of the reduction gear to which torque from the motor is input. The aforementioned rotational output unit is the output shaft of the reduction gear, which outputs the torque of the reduction gear to the drive unit. The apparatus according to claim 1.

5. The amount of backlash is corrected based on the weight parameter relating to the weight of the drive unit. The apparatus according to claim 4.

6. Motor and, A reduction gear to which torque from the aforementioned motor is input, A drive unit to which the torque reduced by the aforementioned reduction gear is input, The apparatus comprises the apparatus according to any one of claims 1 to 5. Agricultural machinery.

7. The drive unit is one of the following: a slewing bearing that rotatably connects the lower and upper parts of the vehicle body of the work machine; a swing bracket that rotatably connects to the vehicle body; a boom that rotatably connects to the swing bracket; an arm that rotatably connects to the boom; or an attachment that rotatably connects to the arm. The work machine according to claim 6.

8. Computers A first process in which the input phase, which is the rotational phase of a rotating input part that rotates based on the torque input to the reduction gear, The reduction gear includes a second process for acquiring the output phase, which is the rotational phase of the rotating output unit that rotates based on the torque from the rotating input unit, A third process for obtaining an estimated phase based on either the input phase or the output phase, and a reduction ratio which is the ratio of the rotational speed of the rotational input unit to the rotational speed of the rotational output unit; A fourth process to obtain a phase difference, which is the difference between the other of the input phase and the output phase and the estimated phase, A fifth process is performed which outputs the amount of backlash based on the phase difference. Method for estimating backlash amount.

9. On the computer, A first step in which the input phase, which is the rotational phase of the rotating input part that rotates based on the torque input to the reduction gear, is obtained in the reduction gear, The second step involves obtaining the output phase, which is the rotational phase of the rotational output unit that rotates based on the torque from the rotational input unit, in the reduction gear, A third step of obtaining an estimated phase based on either the input phase or the output phase, and the reduction ratio which is the ratio of the rotational speed of the rotational input unit to the rotational speed of the rotational output unit, A fourth step involves obtaining a phase difference, which is the difference between the other of the input phase and the output phase and the estimated phase. The fifth step involves outputting the amount of backlash based on the phase difference, and then executing the following: A program for estimating backlash amount.

Images