Inspection device, inspection method, and vehicle

Abstract

To estimate a consumption state of a gear of a vehicle with a simple configuration.SOLUTION: An inspection device for inspecting a vehicle in which driving force generated by a motor is transmitted to driving wheels via a plurality of gears, includes: a generation unit for causing the motor to generate each torque in two rotation directions different from each other in a state where the vehicle is stopped; and an estimation unit for estimating a wear state of the plurality of gears based on a rotation amount of the motor according to the torque in the state where the vehicle is stopped.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an inspection device, an inspection method, and a vehicle. [Background technology]

[0002] A vehicle includes gears for transmitting driving force generated by a driving source to driving wheels. The gears wear as the vehicle travels. Gears that are significantly worn out need to be replaced. It is cumbersome to disassemble the vehicle, remove the gears, and check the wear state of the gears. Patent Document 1 proposes a technology for estimating the wear state of the gears using a laser without removing the gears. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-121151 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 uses a laser to estimate the wear state of the gear, which may result in a complex structure. An object of some aspects of the present invention is to estimate the wear state of the gear of a vehicle with a simple structure. [Means for solving the problem]

[0005] According to some embodiments, there is provided an inspection device for inspecting a vehicle in which driving force generated by a motor is transmitted to driving wheels via a plurality of gears, the inspection device comprising: a generating means for generating torque in the motor in each of two different rotational directions when the vehicle is stopped; and an estimation means for estimating the wear state of the plurality of gears based on the amount of rotation of the motor corresponding to the torque when the vehicle is stopped. Effect of the Invention

[0006] According to some embodiments, the wear state of a vehicle's gears can be estimated with a simple configuration. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating an example configuration of a vehicle according to some embodiments. [Diagram 2] FIG. 2 is a schematic cross-sectional view illustrating an example of the configuration of a power unit according to some embodiments. [Diagram 3] 1A to 1C are schematic diagrams illustrating examples of the configuration of gears according to some embodiments. [Figure 4] FIG. 4 is a flow diagram illustrating an example inspection method according to some embodiments. [Diagram 5] 5A to 5C are diagrams illustrating changes over time in torque and rotation amount according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0009] <Vehicle configuration> With reference to FIG. 1, a configuration example of a vehicle V according to some embodiments will be described. In FIG. 1, a plan view and a side view of the vehicle V are shown. The vehicle V may have the components shown in FIG. 1. The vehicle V may further have components not shown in FIG. 1, or may not have some of the components shown in FIG. 1. The vehicle V may be a vehicle having a motor as a drive source. For example, the vehicle V may be an electric vehicle or a hybrid vehicle. The vehicle V may be a four-wheeled vehicle, a two-wheeled vehicle, or other vehicles. The vehicle V may be an autonomous vehicle having a driving assistance function that automatically travels without the need for a driving operation by an occupant, or may be a vehicle that does not have such a driving assistance function. In FIG. 1, a case will be described where the vehicle V is a four-wheeled electric vehicle.

[0010] The electronic control unit 1 functions as a control device that controls multiple components of the vehicle V, including the power unit 2, the hydraulic device 3, etc. The electronic control unit 1 may be configured by one ECU (Electronic Control Unit), or may be configured by multiple ECUs. The multiple ECUs may each control separate components (the power unit 2, the hydraulic device 3, etc.).

[0011] The electronic control unit 1 includes a processor 1a represented by a CPU (Central Processing Unit), a memory 1b such as a semiconductor memory, and an interface (not shown) with other devices. The memory 1b stores programs executed by the processor 1a, data used by the processor 1a for processing, etc. The interface may include an input / output interface and a communication interface.

[0012] The electronic control unit 1 controls the drive (acceleration) of the vehicle V by controlling the power unit 2. The power unit 2 is a driving unit that generates a driving force (torque) to rotate the drive wheels of the vehicle V. The electronic control unit 1 controls the output of the power unit 2 in response to the driving operation of the driver detected by an operation detection sensor 2a provided on the accelerator pedal AP and an operation detection sensor 2b provided on the brake pedal BP. The electronic control unit 1 may measure the speed of the vehicle V based on the rotation speed of the wheels detected by the wheel speed sensor 2c.

[0013] The electronic control unit 1 controls the braking (deceleration) of the vehicle V by controlling the hydraulic device 3. The hydraulic device 3 is an actuator capable of controlling the hydraulic pressure of hydraulic oil supplied to brake devices 3a (e.g., disc brake devices) provided on each of the four wheels based on the hydraulic pressure transmitted from a brake master cylinder BM. The electronic control unit 1 can control the braking of the vehicle V by controlling the drive of solenoid valves and the like provided in the hydraulic device 3.

[0014] The electronic control unit 1 controls the steering of the vehicle V by controlling the electric power steering device 4. The electric power steering device 4 includes a mechanism for steering the front wheels in response to the driving operation (steering operation) of the driver with respect to the steering wheel ST. The electric power steering device 4 may include a drive unit 4a including a motor that generates a driving force for assisting the steering operation, a steering angle sensor 4b, a torque sensor 4c that detects the steering torque borne by the driver, and the like.

[0015] The electronic control unit 1 controls an information output device 5 that notifies the inside of the vehicle of information. The information output device 5 may include, for example, a display device 5a that notifies the driver of information by image and a voice output device 5b that notifies the driver of information by voice. The display device 5a may include, for example, a display device provided on an instrument panel or a display device provided on a steering wheel ST. The display device 5a may include a head-up display. The information output device 5 may notify the occupant of information by vibration or light.

[0016] The electronic control unit 1 accepts instruction input from the driver via the input device 6. The input device 6 is arranged in a position where the driver can operate it, and may include, for example, a switch group 6a through which the driver issues instructions to the vehicle V, a turn signal lever 6b for activating a turn signal (blinker), and a shift lever 6c for indicating a shift position. The switch group 6a may include a switch for instructing operation of an electric parking brake. In response to an instruction from the driver to operate the electric parking brake, the electronic control unit 1 controls an electric parking brake device 3c provided on the rear wheels, thereby maintaining the vehicle V in a stopped state. Instead of the electric parking brake mechanism, the vehicle V may have a parking brake mechanism that operates in response to the driver's operation of a parking lever or a parking pedal.

[0017] The shift positions that can be set by the shift lever 6c may include a drive range used to move the vehicle V forward, a reverse range used to move the vehicle V backward, a parking range used to keep the vehicle V stopped, and a neutral range to prevent the driving force of the power unit 2 from being transmitted to the drive wheels.

[0018] The electronic control unit 1 may use the communication device 7 to communicate with devices outside the vehicle V. The communication by the communication device 7 may be wireless communication or wired communication.

[0019] <Power unit configuration example> A configuration example of the power unit 2 of the vehicle V will be described with reference to Fig. 2 and Fig. 3(a). Fig. 2 is a cross-sectional view of the power unit 2. Fig. 3(a) is a schematic diagram focusing on the relationship between the motor 11, multiple gears, and multiple shafts among the components of the power unit 2. The power unit 2 may have the components shown in Fig. 2. The power unit 2 may further have components not shown in Fig. 2, or may not have some of the components shown in Fig. 2.

[0020] As shown in FIG. 2, the power unit of the vehicle V has a motor 11, a reduction gear 12, and a differential gear 13 inside a housing 14. The motor 11 can be used as a drive source for accelerating the vehicle V, and may also be used as a generator during deceleration, etc. The housing 14 is divided into three parts in the vehicle width direction. The three divided parts are referred to as a left housing 15, a central housing 16, and a right housing 17, in that order from the left side of the vehicle V. An accommodation section 43 is defined between the left housing 15 and the central housing 16. An accommodation section 44 is defined between the central housing 16 and the right housing 17.

[0021] The motor 11 is disposed in the housing portion 43. The motor 11 has a motor shaft 20, a rotor 21, a stator 22, and a resolver 40. The motor shaft 20 is supported by the left housing 15 via a ball bearing 18, and is supported by the central housing 16 via a ball bearing 19. The rotor 21 is fixed to the motor shaft 20. The stator 22 surrounds the outer periphery of the rotor 21, and is fixed to the central housing 16. Oil is stored in the bottom of the housing 14.

[0022] The resolver 40 is a rotation angle sensor for detecting the rotation angle of the rotor 21. Other rotation angle sensors, for example, an encoder, may be used instead of the resolver 40. The rotation angle of the rotor 21 is referred to as the rotation angle of the motor 11. The rotation angle of the rotor 21 is equal to the rotation angle of the motor shaft 20 fixed to the rotor 21. Furthermore, the rotation angle of the rotor 21 is equal to the rotation angle of the reduction gear 23 fixed to the motor shaft 20.

[0023] The reduction gear 12 is disposed in the housing 44. The reduction gear 12 has a reduction gear 23, a reduction shaft 26, a reduction gear 27, a final drive gear 28, and a final driven gear 29. The reduction gear 23 is fixed to the tip of the motor shaft 20 that protrudes to the right beyond the central housing 16. The reduction shaft 26 is supported by the central housing 16 via an angular roller bearing 24, and is supported by the right housing 17 via an angular roller bearing 25. The reduction gear 27 and the final drive gear 28 are each fixed to the reduction shaft 26. The final driven gear 29 is fixed to the outer periphery of the differential gear 13. The reduction gear 27 meshes with the reduction gear 23. The final driven gear 29 meshes with the final drive gear 28.

[0024] The differential gear 13 is disposed in the housing 44. The outer shell of the differential gear 13 is formed by a differential case 30. The differential case 30 is supported by the central housing 16 via an angular roller bearing 31, and is supported by the right housing 17 via an angular roller bearing 32. An inboard joint 34 is provided at the tip of a long left output shaft 33 extending leftward from the differential case 30. The inboard joint 34 protrudes outward from the left housing 15. An inboard joint 36 is provided at the tip of a short right output shaft 35 extending rightward from the differential case 30. The inboard joint 36 protrudes outward from the right housing 17. The left inboard joint 34 is connected to a left rear wheel 41 via a left half shaft (not shown). The right inboard joint 36 is connected to a right rear wheel 42 via a right half shaft (not shown). The right end of the left output shaft 33 is supported by the differential gear 13. The left end of the left output shaft 33 is supported by the left housing 15 via a ball bearing 37 .

[0025] The power unit 2 further includes a parking gear 38 and a parking pole 39. The parking gear 38 is fixed to the differential case 30. The parking pole 39 is fixed to the housing 14. A recess and a protrusion are alternately formed on the outer peripheral surface of the parking gear 38 in the circumferential direction. The parking pole 39 includes a claw portion that can mesh with the recess of the parking gear 38. The parking pole 39 selectively meshes with the parking gear 38. That is, the parking pole 39 can have a state in which it is meshed with the parking gear 38 and a state in which it is not meshed with the parking gear 38. When the shift lever 6c is in the parking range, the electronic control unit 1 meshes the parking pole 39 with the parking gear 38. This suppresses the rotation of the differential case 30, and maintains the stopped state of the vehicle V. The suppression of the rotation of a specific member may mean that the specific member is fixed relatively to the body of the vehicle V. When the shift lever 6c is not in the parking range, the electronic control unit 1 does not mesh the parking pole 39 with the parking gear 38. This allows the differential case 30 to rotate so as to transmit the driving force generated by the motor 11 to the driving wheels.

[0026] In the vehicle V, the driving force generated by the motor 11 is transmitted to the drive wheels (in the example of FIG. 3(a), the left rear wheel 41 and the right rear wheel 42) via multiple gears (in the example of FIG. 3(a), the differential gear 13, the reduction gear 23, the reduction gear 27, the final drive gear 28, and the final driven gear 29).

[0027] FIG. 3(b) illustrates a modified example of the power unit 2. In the configuration shown in FIG. 3(b), the power unit 2 does not have the reduction shaft 26, the reduction gear 27, and the final drive gear 28. The final driven gear 29 meshes with the reduction gear 23. Even in the modified example of FIG. 3(b), the driving force generated by the motor 11 is transmitted to the drive wheels (the left rear wheel 41 and the right rear wheel 42 in the example of FIG. 3(a)) via a plurality of gears (the differential gear 13, the reduction gear 23, and the final driven gear 29).

[0028] <Gear inspection method> An inspection method for inspecting a vehicle V will be described with reference to the flowchart of FIG. 4. In this inspection method, the wear state of a plurality of gears included in a power unit 2 is inspected. The inspection method of FIG. 4 may be executed by an electronic control unit 1 of the vehicle V. In this case, the electronic control unit 1 functions as an inspection device. Alternatively, the inspection method of FIG. 4 may be executed by an inspection device different from the electronic control unit 1. The inspection device may be mounted on the vehicle V or may be outside the vehicle V. When the inspection device is outside the vehicle V, data used to execute the inspection method of FIG. 4 may be transmitted from the vehicle V to the inspection device. In the following, a case where the electronic control unit 1 of the vehicle V executes the inspection method of FIG. 4 will be described. Each step of the inspection method of FIG. 4 may be performed, for example, by the processor 1a of the electronic control unit 1 executing a program stored in the memory 1b of the electronic control unit 1. Alternatively, some or all of the steps of the inspection method of FIG. 4 may be executed by a dedicated integrated circuit such as an application specific integrated circuit (ASIC). The inspection method of FIG. 4 may be started in response to the power supply (eg, ignition power supply) of the vehicle V being turned on.

[0029] In S401, the electronic control unit 1 determines whether the vehicle V has stopped. If it is determined that the vehicle V has stopped ("YES" in S401), the electronic control unit 1 transitions the process to S402, and otherwise ("NO" in S401) repeats S401. The vehicle V being stopped means that the speed of the vehicle V is zero. The speed of the vehicle V may be calculated based on the output of the wheel speed sensor 2c, for example.

[0030] In S401, the electronic control unit 1 may further determine whether the parking mechanism of the vehicle V has been operated in addition to or instead of the vehicle V being stopped. In this case, the electronic control unit 1 executes the steps from S402 onward in response to the parking mechanism of the vehicle V being operated. The parking mechanism of the vehicle V may include a parking gear 38 and a parking pole 39. Alternatively or in addition to this, the parking mechanism of the vehicle V may include an electric parking brake device 3c. The electronic control unit 1 operates the parking mechanism in response to the shift position of the vehicle V being changed to the parking range. Specifically, the electronic control unit 1 engages the parking pole 39 with the parking gear 38 in response to the shift position of the vehicle V being changed to the parking range. In addition to this, the electronic control unit 1 may operate the electric parking brake in response to the shift position of the vehicle V being changed to the parking range.

[0031] The determination in S401 may be made based on another condition. For example, an additional condition may be that a predetermined time (e.g., 24 hours) has elapsed since the condition in S401 was last satisfied, or that the vehicle V has traveled a predetermined distance (e.g., 10 km). By further determining such a condition, the steps from S402 onward are prevented from being executed excessively frequently.

[0032] In S402, the electronic control unit 1 causes the motor 11 to generate torques in two different rotation directions while the vehicle V is stopped. The two different rotation directions may be clockwise and counterclockwise around the motor shaft 20 of the motor 11. With reference to FIG. 5(a), an example of the torque generated by the motor 11 will be described. The horizontal axis of the graph 501 in FIG. 5(a) represents the elapsed time since the motor 11 starts generating torque. The vertical axis of the graph 501 in FIG. 5(a) represents the torque generated by the motor 11. One of the two different rotation directions is defined as a positive direction, and the value of the torque that rotates the motor 11 in this direction is defined as positive. The other of the two different rotation directions is defined as a negative direction, and the value of the torque that rotates the motor 11 in this direction is defined as negative.

[0033] In the example of Fig. 5(a), the electronic control unit 1 causes the motor 11 to generate torque of a sine wave having a preset period and amplitude. Alternatively, the electronic control unit 1 may cause the motor 11 to generate torque of another waveform. The electronic control unit 1 causes the motor 11 to continue generating torque for a preset time (e.g., 10 seconds) or a preset number of waves (e.g., 10). The electronic control unit 1 causes the motor 11 to generate torque of an amplitude that maintains the vehicle V stopped.

[0034] In S403, the electronic control unit 1 measures the amount of rotation of the motor 11 according to the torque generated in S402 while the vehicle V is stopped. The amount of rotation of the motor 11 may be a range within which the rotation angle of the motor 11 can be taken. The rotation angle of the motor 11 is measured, for example, by the resolver 40. An example of the amount of rotation of the motor 11 will be described with reference to FIG. 5(b). The horizontal axis of the graph 502 in FIG. 5(b) represents the elapsed time since the motor 11 starts generating torque. The vertical axis of the graph 502 in FIG. 5(b) represents the rotation angle of the motor 11. In the graph 502, the rotation angle at the time when the motor 11 starts generating torque is set to zero.

[0035] As shown in FIG. 4(a), when the parking pole 39 is engaged with the parking gear 38, the rotation of the differential case 30 of the differential gear 13 is suppressed. Therefore, the rotation of the final driven gear 29 fixed relatively to the differential case 30 is also suppressed. On the other hand, since there is a backlash in the meshing between the final drive gear 28 and the final driven gear 29, the final drive gear 28 can rotate within the range of this backlash. The backlash is a gap that is intentionally provided in the rotation direction. Since the final drive gear 28 is rotatable, the reduction gear 27 fixed relatively to the final drive gear 28 can also rotate.

[0036] Backlash also exists in the meshing between the reduction gear 23 and the reduction gear 27. Therefore, the reduction gear 23 can rotate within a range that is the sum of the range in which the reduction gear 27 can rotate and the range of this backlash. Therefore, the motor shaft 20, which is fixed relatively to the reduction gear 23, can also rotate. In the example of FIG. 5(b), as shown in the graph 502, in response to the motor 11 generating torque in the positive direction, the motor 11 can rotate until the rotation angle becomes v1. In response to the motor 11 generating torque in the negative direction, the motor 11 can rotate until the rotation angle becomes v2. The absolute value of v1 and the absolute value of v2 can be different values ​​depending on the positional relationship of the gears at the start of torque generation. The electronic control unit 1 measures the range (v1-v2) in which the motor 11 can rotate while the vehicle V is in a stopped state as the amount of rotation of the motor 11.

[0037] With reference to Fig. 5(c), the amount of rotation of motor 11 when backlash increases due to wear of gears will be described. The horizontal axis of graph 503 in Fig. 5(c) represents the elapsed time from when motor 11 starts generating torque. The vertical axis of graph 503 in Fig. 5(c) represents the rotation angle of motor 11. In graph 503, the rotation angle at the time when motor 11 starts generating torque is set to zero.

[0038] 5(c), as shown in graph 502, in response to the motor 11 generating torque in the positive direction, the motor 11 can rotate until the rotation angle reaches v3. In response to the motor 11 generating torque in the negative direction, the motor 11 can rotate until the rotation angle reaches v4. Due to the increase in backlash, the amount of rotation of the motor 11 in the case shown in graph 503 (v3-v4) is greater than the amount of rotation of the motor 11 in the case shown in graph 502 (v1-v2).

[0039] In S404, the electronic control unit 1 estimates the wear state of the multiple gears included in the power unit 2 based on the rotation amount of the motor 11 measured in S403. For example, the electronic control unit 1 may calculate an index representing the wear state of the multiple gears based on the rotation amount of the motor 11 measured in S403. In the following description, the index representing the wear state of the multiple gears is referred to as a wear index. The electronic control unit 1 may use the rotation amount of the motor 11 measured in S403 as the wear index. Alternatively, the wear index may be a value obtained by subtracting the rotation amount of the motor 11 measured in S403 from the rotation amount of the motor 11 measured in S403. Alternatively, the wear index may be a value obtained by dividing the rotation amount of the motor 11 measured in S403 by the rotation amount of the motor 11 measured in S403. The amount of rotation of the motor 11 measured during inspection of the vehicle V before shipment may be stored, for example, in the memory 1b of the electronic control unit 1, or may be received from a server external to the vehicle V. The amount of rotation of the motor 11 measured during inspection of the vehicle V before shipment is an example of the amount of rotation of the motor 11 in a state where wear on the multiple gears is low, and the amount of rotation of the motor 11 measured at another time point may be used.

[0040] The wear state represented by the wear index based on the rotation amount of the motor 11 measured in S403 represents the wear state of the gears on the torque transmission path from the motor 11 to the parking gear 38 among the multiple gears included in the power unit 2. Specifically, in the configuration example of FIG. 4(a), the reduction gear 23, the reduction gear 27, the final drive gear 28, and the final driven gear 29 are included on the torque transmission path from the motor 11 to the parking gear 38. In the configuration example of FIG. 4(b), the reduction gear 23 and the final driven gear 29 are included on the torque transmission path from the motor 11 to the parking gear 38. In the configuration example of FIG. 4(a) or FIG. 4(b), when the parking gear 38 is fixed to the left output shaft 33 or the right output shaft 35, the differential gear 13 is further included on the torque transmission path from the motor 11 to the parking gear 38.

[0041] 4(a), when a plurality of meshes (for example, mesh between the reduction gear 23 and the reduction gear 27 and mesh between the final drive gear 28 and the final driven gear 29) are included on the torque transmission path from the motor 11 to the parking gear 38, the electronic control unit 1 may calculate the wear index for each of the plurality of meshes. This calculation method will be specifically described below.

[0042] The ratio of the reduction gear 27 to the reduction gear 23 is i1. The amount of rotation of the reduction gear 27 to the reduction gear 23 is R1. The amount of rotation of the final driven gear 29 to the final drive gear 28 is R2. R1 and R2 can change depending on the wear state of these gears. The results of a preliminary test showed that R1 and R2 change with wear of these gears. R2=a×R1…(Formula 1) It is known that the change satisfies the following. a may be a constant or a function according to the total amount of rotation of the motor 11. In this case, if the amount of rotation of the motor 11 is R, then R=R1+R2×i1…(Formula 2) holds. i1 is determined by the number of teeth of the reduction gear 23 and the number of teeth of the reduction gear 27, a is given by a previous test (and possibly the current total rotation amount of the motor 11), and R is measured in S404. Therefore, the electronic control unit 1 can calculate R1 and R2 by simultaneously solving Equation 1 and Equation 2. After that, the electronic control unit 1 calculates a wear index for the meshing between the reduction gear 23 and the reduction gear 27 based on R1, and calculates a wear index for the meshing between the final drive gear 28 and the final driven gear 29 based on R2. These wear indexes represent the wear state for each of the multiple meshes.

[0043] The electronic control unit 1 may store the estimated wear state (for example, a wear index representing the wear state) in the memory 1b in association with the current time, or may transmit the same to a server outside the vehicle V.

[0044] In S405, the electronic control unit 1 judges whether the wear state estimated in S404 satisfies a predetermined condition. If the wear state is judged to satisfy the predetermined condition ("YES" in S405), the electronic control unit 1 transitions the process to S406, and otherwise ("NO" in S405), transitions the process to S401. The predetermined condition may be a condition indicating that replacement of a gear included in the power unit 2 is recommended. For example, the predetermined condition may be that the wear index calculated in S404 exceeds a predetermined threshold. This threshold may be set in advance and stored in the memory 1b. In the case where a wear index is calculated for each of a plurality of meshes, the predetermined condition may be that at least one of the plurality of wear indexes exceeds a predetermined threshold. A different threshold value may be set for each of the plurality of wear indexes.

[0045] In S406, the electronic control unit 1 notifies that a plurality of gears included in the power unit 2 are worn out. The notification in S406 may be directed to the driver of the vehicle V, for example, using the information output device 5. Alternatively or in addition, the notification in S406 may be directed to the owner or manager of the vehicle V. S406 may be omitted. If it is not determined that the predetermined condition is satisfied in S405, the electronic control unit 1 checks the wear state of the gears again the next time the vehicle V stops.

[0046] According to the above-described embodiment, the wear state of the gears is estimated using the motor 11, which is the drive source of the vehicle V, so that the wear state of the gears can be estimated with a simple configuration. Also, since the motor 11 generates torque when the vehicle V is stopped, the wear state of the gears can be estimated with high accuracy. By estimating the wear state of the gears with high accuracy in this way, the product life of the gears can be extended. Furthermore, according to some embodiments, the wear state of the gears is estimated for each of a plurality of meshes, so that the wear state of the gears can be estimated with even higher accuracy.

[0047] <Summary of the embodiment> [Item 1] An inspection device (1) for inspecting a vehicle (V) in which driving force generated by a motor (11) is transmitted to driving wheels (41, 42) via a plurality of gears (23, 27, 28, 29), comprising: A generating means (S402) for generating torques in two different rotation directions in the motor while the vehicle is stopped; and an estimation means (S404) for estimating a wear state of the plurality of gears based on an amount of rotation of the motor corresponding to the torque when the vehicle is stopped. According to this item, the wear condition of the gear can be estimated with a simple configuration. [Item 2] 2. The inspection device according to claim 1, wherein the generating means causes the motor to generate the torque in response to operation of a parking mechanism (38, 39, 3c) of the vehicle. According to this item, unintended movement of the vehicle can be suppressed. [Item 3] 3. The inspection device according to item 2, wherein the parking mechanism operates in response to a change in the shift position of the vehicle to a parking range. This item identifies that the parking mechanism is operating. [Item 4] The inspection device according to item 2 or 3, wherein the parking mechanism includes a parking gear (38) and a parking pole (39) selectively meshed with the parking gear. According to this item, the vehicle can be reliably maintained in a stopped state. [Item 5] 5. The inspection device according to item 4, wherein the estimation means estimates a wear state of a gear among the plurality of gears that is on a torque transmission path from the motor to the parking gear. According to this item, the gears for which the wear state can be estimated are clarified. [Item 6] The plurality of gears are provided on the transmission path. A first gear (23); a second gear (27) meshing with the first gear; A third gear (28); a fourth gear (29) meshing with the third gear, 6. The inspection device according to item 5, wherein the estimation means estimates a wear state for each of the meshing between the first gear and the second gear and the meshing between the third gear and the fourth gear. According to this item, the wear state of the gear can be estimated with high accuracy. [Item 7] The inspection device according to any one of items 1 to 6, further comprising a notification means (S406) for notifying that the plurality of gears are worn in response to the estimated wear state satisfying a predetermined condition. This item allows the user to understand the wear condition of the gears. [Item 8] A vehicle (V) equipped with an inspection device according to any one of items 1 to 7. According to this item, the above-mentioned effects are provided in the form of a vehicle. [Item 9] 1. A method for inspecting a vehicle (V) in which driving force generated by a motor (11) is transmitted to driving wheels (41, 42) via a plurality of gears (23, 27, 28, 29), comprising the steps of: A generating step (S402) of causing the motor to generate torques in two different rotation directions while the vehicle is stopped; and an estimation step (S404) of estimating a wear state of the plurality of gears based on an amount of rotation of the motor corresponding to the torque when the vehicle is stopped. According to this item, the wear condition of the gear can be estimated with a simple configuration.

[0048] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention. [Explanation of symbols]

[0049] V vehicle, 1 electronic control unit, 2 power unit, 11 motor

Claims

1. An inspection device for inspecting a vehicle in which a driving force generated by a motor is transmitted to a driving wheel via a plurality of gears, a generating means for causing the motor to generate torques in two different rotation directions while the vehicle is stopped; and an estimation means for estimating a wear state of the plurality of gears based on an amount of rotation of the motor corresponding to the torque when the vehicle is stopped.

2. 2. The inspection device according to claim 1, wherein the generating means causes the motor to generate the torque in response to an operation of a parking mechanism of the vehicle.

3. 3. The inspection device according to claim 2, wherein the parking mechanism operates in response to a shift position of the vehicle being changed to a parking range.

4. The inspection device according to claim 2 , wherein the parking mechanism includes a parking gear and a parking pole selectively meshed with the parking gear.

5. 5. The inspection device according to claim 4, wherein the estimation means estimates the wear state of a gear, among the plurality of gears, that is located on a torque transmission path from the motor to the parking gear.

6. The plurality of gears are provided on the transmission path. A first gear; a second gear meshing with the first gear; A third gear; a fourth gear meshing with the third gear, 6. The inspection device according to claim 5, wherein the estimation means estimates a wear state for each of the meshing between the first gear and the second gear and the meshing between the third gear and the fourth gear.

7. 2. The inspection device according to claim 1, further comprising a notification unit that notifies the user that the plurality of gears are worn when the estimated wear state satisfies a predetermined condition.

8. A vehicle comprising an inspection device according to any one of claims 1 to 7.

9. 1. A method for inspecting a vehicle in which a driving force generated by a motor is transmitted to a driving wheel via a plurality of gears, comprising the steps of: a generating step of causing the motor to generate torques in two different rotation directions while the vehicle is stopped; and an estimation step of estimating a wear state of the plurality of gears based on an amount of rotation of the motor corresponding to the torque when the vehicle is stopped.

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