Motor drive assembly for work machine, and work machine

Abstract

This motor drive assembly for a work machine comprises: a motor; a final drive assembly; and a clutch. The final drive assembly includes a gear mechanism and a brake. The gear mechanism transmits rotation from the motor. The brake inhibits the rotation from the motor. The clutch is connected to the motor and the final drive assembly. The clutch connects the motor and the final drive assembly in an engaged state. The clutch releases the motor from the final drive assembly in a disengaged state.

Description

Motor drive assembly for a working machine and a working machine

[0001] It relates to a motor drive assembly for a working machine and a working machine.

[0002] The motor drive assembly for a working machine includes a motor and a final drive assembly. The final drive assembly is connected to the motor. For example, the motor drive assembly of Patent Document 1 includes a brake and a planetary gear mechanism. The brake is connected to the motor. The planetary gear mechanism is connected to a sprocket. The rotation from the motor is transmitted to the sprocket through the brake and the planetary gear mechanism.

[0003] U.S. Patent No. 12,084,132

[0004] In the above-described motor drive assembly, the final drive assembly may be affected by the inertia moment of the motor. For example, when the brake is actuated, the braking distance of the working machine may increase due to the inertia moment of the motor. Or, when the working machine is suddenly decelerated by a load, such as when starting excavation by pushing down the blade during traveling, excessive peak torque may occur in the rotating elements such as the gears or shafts of the final drive assembly due to the inertia moment of the motor. The object of the present disclosure is to reduce the influence on the final drive assembly caused by the inertia moment of the motor in the motor drive assembly for a working machine.

[0005] The motor drive assembly for a working machine according to one aspect of the present disclosure includes a motor, a final drive assembly, and a clutch. The final drive assembly includes a gear mechanism and a brake. The gear mechanism transmits the rotation from the motor. The brake brakes the rotation from the motor. The clutch is connected to the motor and the final drive assembly. The clutch connects the motor to the final drive assembly in an engaged state. The clutch releases the motor from the final drive assembly in a disengaged state.

[0006] A motor drive assembly for a work machine according to another aspect of the present disclosure comprises a motor, a final drive assembly, and a clutch. The final drive assembly is driven by the motor. The clutch is provided between the motor and the final drive assembly and slips when a torque exceeding a predetermined magnitude is applied.

[0007] Other aspects of the present disclosure of work machines include a body and a running gear. The running gear supports the body. The running gear includes the motor drive assembly described above.

[0008] According to this disclosure, in a motor drive assembly for a work machine, the influence on the final drive assembly due to the motor's moment of inertia is reduced.

[0009] This is a perspective view of a work machine according to an embodiment. This is a cross-sectional view of a motor drive assembly according to the first embodiment. This is a skeleton diagram of a motor drive assembly according to the first embodiment. This is an enlarged cross-sectional view of a motor drive assembly according to the first embodiment. This is an enlarged cross-sectional view of a motor drive assembly according to the first embodiment. This is an enlarged cross-sectional view of a motor drive assembly according to the second embodiment. This is a skeleton diagram of a motor drive assembly according to the third embodiment.

[0010] The following description of the working machine according to the embodiment will be made with reference to the drawings. Figure 1 is a perspective view of the working machine 1 according to the embodiment. The working machine 1 according to this embodiment is a bulldozer. As shown in Figure 1, the working machine 1 comprises a body 2, a working machine 3, and left and right traveling devices 4 and 5. The body 2 includes a driver's cab 6 and a power room 7. The power room 7 is located in front of the driver's cab 6. The working machine 3 is operably supported relative to the body 2. The working machine 3 includes a blade 8.

[0011] The running gears 4 and 5 support the vehicle body 2. The left running gear 4 includes a track 11, a motor drive assembly 12A, and a track frame 13. The track frame 13 supports the track 11 via several road wheels (not shown) and idlers. The track 11 is wound around the motor drive assembly 12A. The motor drive assembly 12A is attached to the track frame 13. The axis Ax1 of the motor drive assembly 12A extends in the left-right direction of the work machine 1. In the following description, the direction parallel to axis Ax1 is defined as the axial direction. The configuration of the right running gear 5 is the same as that of the left running gear 4, so its description is omitted.

[0012] Figure 2 is a cross-sectional view of the motor drive assembly 12A according to the first embodiment. Figure 3 is a skeleton diagram of the motor drive assembly 12A according to the first embodiment. The motor drive assembly 12 includes a motor assembly 21 and a final drive assembly 22. The motor assembly 21 is connected to the final drive assembly 22. In this embodiment, the motor assembly 21 is an electric motor.

[0013] The motor assembly 21 includes a motor 40, a motor case 41, and a clutch 46. The motor 40 includes a stator 42, a rotor 43, and a motor shaft 44A. The stator 42 and rotor 43 are located within the motor case 41. The stator 42 is fixed to the inner surface of the motor case 41. The motor shaft 44A extends in the axial direction. The motor shaft 44A is fixed to the rotor 43. The motor shaft 44A rotates integrally with the rotor 43. The motor shaft 44A is rotatably supported in the motor case 41 via bearings 26 and 27.

[0014] The clutch 46 is connected to the motor 40 and the final drive assembly 22. The clutch 46 is positioned between the motor 40 and the final drive assembly 22 in the power transmission path of the motor 40. The clutch 46 is located inside the motor case 41. Figure 4 is an enlarged cross-sectional view of the motor drive assembly 12A according to the first embodiment. As shown in Figure 4, the clutch 46 includes a rotating shaft 44B, a clutch hub 93, a plurality of clutch discs 47A, 47B, and a clutch piston 48.

[0015] The motor shaft 44A includes a hole 82 that extends in the axial direction. The rotating shaft 44B extends in the axial direction through the hole 82 of the motor shaft 44A. The clutch hub 93 is fixed to the rotating shaft 44B. A bush 94 is press-fitted into the clutch hub 93. The clutch hub 93 is supported by the motor shaft 44A in the axial direction via thrust bearings 95 and 96. The clutch hub 93 rotates integrally with the rotating shaft 44B. The rotating shaft 44B and the clutch hub 93 are rotatable relative to the motor shaft 44A. The rotating shaft 44B protrudes axially outward from the motor case 41.

[0016] As shown in Figure 4, the plurality of clutch discs 47A, 47B include a first clutch disc 47A and a second clutch disc 47B. The first clutch disc 47A and the second clutch disc 47B are arranged alternately in the axial direction. The first clutch disc 47A is connected to the motor shaft 44A so as to be non-rotatable and movable in the axial direction relative to the motor shaft 44A. The second clutch disc 47B is connected to the clutch hub 93 so as to be non-rotatable and movable in the axial direction relative to the clutch hub 93. The second clutch disc 47B rotates integrally with the clutch hub 93 and the rotating shaft 44B.

[0017] The clutch piston 48 is arranged facing a plurality of clutch discs 47A, 47B in the axial direction. The clutch piston 48 is supported on the motor shaft 44A so as to be movable in the axial direction. The motor shaft 44A includes a clutch oil chamber 80. Hydraulic fluid is supplied to the clutch oil chamber 80 through an oil passage 84 provided in the motor shaft 44A and the motor case 41. The clutch piston 48 is driven by the supply of hydraulic fluid to the clutch oil chamber 80.

[0018] When no hydraulic fluid is supplied to the clutch oil chamber 80, the clutch piston 48 does not press against the clutch discs 47A and 47B. Therefore, the motor shaft 44A is free from the rotating shaft 44B (hereinafter referred to as the disengaged state). In this case, the rotating shaft 44B is rotatable relative to the motor shaft 44A. Note that the disengaged state is not limited to the case where the first clutch disc 47A and the second clutch disc 47B are completely separated from each other, but may also include the case where the first clutch disc 47A and the second clutch disc 47B are sliding against each other.

[0019] When hydraulic fluid is supplied to the clutch oil chamber 80, the clutch piston 48 presses the first clutch disc 47A toward the second clutch disc 47B. As a result, the first clutch disc 47A comes into contact with the second clutch disc 47B, and the motor shaft 44A is connected to the rotating shaft 44B (hereinafter referred to as the engaged state). In this case, the rotating shaft 44B rotates integrally with the motor shaft 44A.

[0020] As shown in Figure 2, the final drive assembly 22 is located outside the motor assembly 21 in the axial direction. The final drive assembly 22 includes a fixed case 23, a final drive housing 24, and a sprocket 25. The final drive assembly 22 is located coaxially with the motor assembly 21. The fixed case 23 is located coaxially with the motor shaft 44A. As will be described in detail later, the final drive housing 24 is rotatably supported by the fixed case 23. The final drive assembly 22 is fixed to the track frame 13 via the fixed case 23. The motor case 41 is attached to the fixed case 23. The motor assembly 21 is fixed to the track frame 13 via the fixed case 23.

[0021] The fixed case 23 includes a fixed case housing 73 and a partition wall 74. The fixed case housing 73 includes a cylindrical portion 75 and a flange 76. The flange 76 protrudes radially outward from the cylindrical portion 75. The cylindrical portion 75 extends axially. The cylindrical portion 75 supports the final drive housing 24 via bearings 77 and 78. The partition wall 74 is a separate component from the fixed case housing 73. The partition wall 74 separates the inside of the motor case 41 from the inside of the fixed case housing 73.

[0022] The final drive housing 24 is positioned coaxially with the fixed case 23. The final drive housing 24 is rotatably supported by the fixed case 23. The sprocket 25 is fixed to the outer circumference of the final drive housing 24. The track 11 is wound around the sprocket 25.

[0023] As shown in Figure 2, the final drive assembly 22 includes a first planetary gear mechanism 51, a central shaft 45, a brake 52, a second planetary gear mechanism 53, and a third planetary gear mechanism 54. The first planetary gear mechanism 51, the central shaft 45, the brake 52, the second planetary gear mechanism 53, and the third planetary gear mechanism 54 are arranged coaxially with the motor shaft 44A.

[0024] The first planetary gear mechanism 51 is located outside the motor assembly 21 in the axial direction. The first planetary gear mechanism 51 is connected to the clutch 46. The first planetary gear mechanism 51 is located between the motor assembly 21 and the brake 52 in the axial direction. The first planetary gear mechanism 51 is located between the clutch 46 and the brake 52 in the power transmission path of the motor 40. The first planetary gear mechanism 51 includes a first sun gear 55, a first planetary gear 56, a first ring gear 57, and a first carrier 58.

[0025] The first sun gear 55 is fixed to the rotating shaft 44B of the clutch 46. The first sun gear 55 rotates integrally with the rotating shaft 44B. The first planetary gear 56 meshes with the first sun gear 55. The first planetary gear 56 is capable of revolving around the first sun gear 55. The first planetary gear 56 is supported by the first carrier 58 so as to be able to rotate. The first ring gear 57 meshes with the first planetary gear 56. The first ring gear 57 is connected to the fixed case 23. The first ring gear 57 is fixed to the fixed case 23 so as not to rotate.

[0026] The first carrier 58 rotatably supports the first planetary gear 56. The first carrier 58 rotates around the first sun gear 55 as the first planetary gear 56 revolves. The central shaft 45 extends in the axial direction. The central shaft 45 is rotatably supported in the fixed case 23 via bearings 49, 50. The first carrier 58 is fixed to the central shaft 45. The central shaft 45 rotates integrally with the first carrier 58.

[0027] The brake 52 is located outside the first planetary gear mechanism 51 in the axial direction. The brake 52 is connected to the first planetary gear mechanism 51 via the central shaft 45. The brake 52 brakes the rotation of the central shaft 45, thereby braking the sprocket 25. Figure 5 is an enlarged cross-sectional view of the motor drive assembly 12. As shown in Figure 5, the brake 52 includes a brake hub 59, a plurality of brake discs 60, 61, a brake piston 62, and a biasing member 63. The brake hub 59 is fixed to the central shaft 45. The brake hub 59 rotates integrally with the central shaft 45.

[0028] The multiple brake discs 60, 61 include a first brake disc 60 and a second brake disc 61. The first brake disc 60 is connected to the brake hub 59 so as to be non-rotatable and axially movable relative to the brake hub 59. The first brake disc 60 rotates integrally with the brake hub 59. The second brake disc 61 is positioned axially opposite to the first brake disc 60. The second brake disc 61 is supported by a fixed case 23 so as to be axially movable.

[0029] The brake piston 62 is positioned axially opposite the brake discs 60 and 61. The brake piston 62 is supported by a fixed case 23 so as to be movable in the axial direction. The biasing member 63 is, for example, a coil spring. Alternatively, the biasing member 63 may be another type of spring, such as a leaf spring. The biasing member 63 biases the brake piston 62 in a direction that presses against the brake discs 60 and 61.

[0030] The fixed case 23 includes a brake fluid chamber 64. When hydraulic fluid is supplied to the brake fluid chamber 64, the brake piston 62 is driven. When hydraulic fluid is not supplied to the brake fluid chamber 64, the brake piston 62 presses against the brake discs 60 and 61 by the biasing force of the biasing member 63. As a result, the first brake disc 60 and the second brake disc 61 press against each other, and the brake 52 brakes the central axis 45 (hereinafter referred to as the braking state). When hydraulic fluid is supplied to the brake fluid chamber 64, the brake piston 62 moves away from the brake discs 60 and 61 against the biasing force of the biasing member 63. As a result, the first brake disc 60 and the second brake disc 61 move away from each other, and the brake 52 releases the central axis 45 (hereinafter referred to as the unbraked state). In other words, the brake 52 is a negative brake in which the braking state is released by the supply of hydraulic fluid.

[0031] As shown in Figure 2, the second planetary gear mechanism 53 is arranged coaxially with the central shaft 45. The second planetary gear mechanism 53 is connected to the first planetary gear mechanism 51 via the central shaft 45. The second planetary gear mechanism 53 is located outside the brake 52 in the axial direction. The second planetary gear mechanism 53 includes a second sun gear 65, a second planetary gear 66, a second ring gear 67, and a second carrier 68.

[0032] The second sun gear 65 is fixed to the central axis 45. The second sun gear 65 rotates integrally with the central axis 45. The second planetary gear 66 meshes with the second sun gear 65. The second planetary gear 66 is capable of revolving around the second sun gear 65. The second planetary gear 66 is supported by the second carrier 68 so as to be able to rotate. The second ring gear 67 meshes with the second planetary gear 66. The second ring gear 67 is fixed to the inner surface of the final drive housing 24. The second ring gear 67 rotates together with the final drive housing 24. The second carrier 68 rotatably supports the second planetary gear 66. The second carrier 68 rotates around the second sun gear 65 along with the revolving of the second planetary gear 66.

[0033] The third planetary gear mechanism 54 is arranged coaxially with the central axis 45. The third planetary gear mechanism 54 is connected to the second planetary gear mechanism 53. In the axial direction, the third planetary gear mechanism 54 is located outside the brake 52. In the axial direction, the third planetary gear mechanism 54 is located inside the second planetary gear mechanism 53. The third planetary gear mechanism 54 includes a third sun gear 69, a third planetary gear 70, and a third ring gear 71.

[0034] The third sun gear 69 is positioned on the outer circumference of the central axis 45. The third sun gear 69 includes a hole 72, which extends axially through the third sun gear 69. The central axis 45 extends through the hole 72 of the third sun gear 69. The third sun gear 69 is rotatable relative to the central axis 45. The third sun gear 69 is fixed to the second carrier 68. The third sun gear 69 rotates together with the second carrier 68.

[0035] The third planetary gear 70 meshes with the third sun gear 69. The third planetary gear 70 is supported by the fixed case 23 so as to be able to rotate on its own axis but not be able to revolve around the third sun gear 69. The third ring gear 71 meshes with the third planetary gear 70. The third ring gear 71 is fixed to the inner surface of the final drive housing 24. The third ring gear 71 rotates together with the final drive housing 24.

[0036] In the final drive assembly 22 described above, the first planetary gear mechanism 51 reduces the rotation of the motor shaft 44A and transmits it to the central shaft 45. The second planetary gear mechanism 53 and the third planetary gear mechanism 54 reduce the rotation of the central shaft 45 and transmit it to the final drive housing 24. In detail, the rotation of the motor shaft 44A is transmitted to the central shaft 45 in the first planetary gear mechanism 51 via the first sun gear 55, the first planetary gear 56, and the first carrier 58.

[0037] The rotation of the central shaft 45 is transmitted to the final drive housing 24 via the second sun gear 65, second planetary gear 66, and second ring gear 67 in the second planetary gear mechanism 53. The revolution of the second planetary gear 66 causes the second carrier 68 to rotate, and the rotation of the second carrier 68 is transmitted to the final drive housing 24 via the third sun gear 69, third planetary gear 70, and third ring gear 71 in the third planetary gear mechanism 54. As a result, the sprocket 25 rotates together with the final drive housing 24.

[0038] As shown in Figure 3, the work machine 1 includes an engine 14, a generator 15, a PTO 16, a hydraulic pump 17, a control valve 18, and a controller 19. The generator 15 generates electricity when driven by the engine 14. The electricity generated by the generator 15 is supplied to the motor 40 via an inverter / converter (not shown).

[0039] The PTO 16 transmits the driving force from the engine 14 to the hydraulic pump 17. The hydraulic pump 17, driven by the driving force from the engine 14, discharges hydraulic fluid to the hydraulic circuits 91 and 92. The control valve 18 controls the hydraulic fluid supplied from the hydraulic circuits 91 and 92 to the clutch 46 and the brake 52. The controller 19 includes, for example, a processor and memory. The controller 19 controls the clutch 46 and the brake by electrically controlling the control valve 18.

[0040] In detail, the controller 19 switches the clutch 46 between an engaged and disengaged state by controlling the hydraulic fluid supplied to the clutch oil chamber 80. When hydraulic fluid is supplied to the clutch oil chamber 80, the clutch 46 becomes engaged. As a result, the motor shaft 44A is connected to the first planetary gear mechanism 51 via the rotating shaft 44B of the clutch 46, and the rotation of the motor shaft 44A is transmitted to the final drive assembly 22. When the supply of hydraulic fluid to the clutch oil chamber 80 is stopped, the clutch 46 becomes disengaged. As a result, the motor shaft 44A is released from the first planetary gear mechanism 51, and the rotation of the motor shaft 44A is not transmitted to the final drive assembly 22.

[0041] The controller 19 switches the brake 52 between a braking state and a non-braking state by controlling the hydraulic oil supplied to the brake oil chamber 64. When the hydraulic oil is supplied to the brake oil chamber 64, the brake 52 becomes a non-braking state. Thereby, the brake 52 releases the central axis 45. When the supply of the hydraulic oil to the brake oil chamber 64 is stopped, the brake 52 becomes a braking state. Thereby, the brake 52 brakes the central axis 45.

[0042] For example, when the power supply is lost due to an abnormality in the working machine 1, the operation of the controller 19 stops. Therefore, by stopping the supply of the hydraulic oil to the brake oil chamber 64, the brake 52 becomes a braking state. Thereby, even when the power supply is lost due to an abnormality in the working machine 1, the working machine 1 can be braked (hereinafter referred to as an emergency brake).

[0043] Also, when the operation of the controller 19 stops, the supply of the hydraulic oil to the clutch oil chamber 80 also stops. Therefore, at the time of the emergency brake, when the clutch 46 becomes a disengaged state, the motor 40 is released from the final drive assembly 22. Therefore, by not transmitting the inertia moment of the motor 40 to the final drive assembly 22, the braking distance of the working machine 1 at the time of the emergency brake can be shortened.

[0044] Next, the motor drive assembly 12B according to the second embodiment will be described. FIG. 6 is an enlarged cross-sectional view of the motor drive assembly 12B according to the second embodiment. As shown in FIG. 6, the clutch 46 includes a biasing member 85 instead of the hydraulic oil chamber 80. The biasing member 85 biases the clutch piston 48 in a direction in which the clutch disks 47A and 47B contact each other. The biasing member 85 is, for example, a leaf spring. However, the biasing member 85 may be another spring such as a coil spring.

[0045] The clutch 46 connects the motor to the final drive assembly 22 by the biasing force of the biasing member 85. The clutch 46 is configured such that the clutch discs 47A and 47B slide against each other when the torque applied to the clutch 46 exceeds a predetermined value. At least one of the diameters of the clutch discs 47A and 47B, the friction coefficients of the clutch discs 47A and 47B, and the biasing force of the biasing member 85 are set accordingly. Therefore, the clutch 46 releases the motor 40 from the final drive assembly 22 when the torque applied to the clutch 46 exceeds a predetermined value. Other configurations of the motor drive assembly 12B according to the second embodiment are the same as those of the motor drive assembly 12A according to the first embodiment described above.

[0046] In the motor drive assembly 12B according to the second embodiment, when excessive torque is applied to the final drive assembly 22, the clutch 46 releases the motor from the final drive assembly 22. For example, when the work machine 1 is rapidly decelerated at the start of excavation, the moment of inertia of the motor 40 causes an excessive peak torque to act on the gears or shafts of the final drive assembly 22. In such cases, the clutch 46 releases the motor 40 from the final drive assembly 22, thereby reducing the load on the rotating elements of the final drive assembly 22.

[0047] Next, a motor drive assembly 12C according to the third embodiment will be described. Figure 7 is a skeleton diagram of the motor drive assembly 12C according to the third embodiment. As shown in Figure 7, the motor drive assembly 12C according to the third embodiment includes a motor 40, a clutch 46, a first planetary gear mechanism 51, a brake 52, a parallel shaft gear 86, and a second planetary gear mechanism 53.

[0048] The clutch 46 and the first planetary gear mechanism 51 are arranged coaxially with the motor shaft 44A. The clutch 46 is connected to the motor 40 and the first planetary gear mechanism 51. The configurations of the motor 40, the clutch 46, and the first planetary gear mechanism 51 of the motor drive assembly 12C according to the third embodiment are the same as the configurations of the motor and the clutch 46 of the motor drive assembly 12A according to the first embodiment, respectively.

[0049] The brake 52 is arranged coaxially with the motor shaft 44A. The brake 52 is arranged on the outer periphery of the first ring gear 57. The brake 52 brakes the first ring gear 57. The parallel shaft gear 86 reduces the rotation of the first planetary gear mechanism 51 and transmits it to the second planetary gear mechanism 53. The parallel shaft gear 86 includes a first gear 87 and a second gear 88. The first gear 87 is fixed to the first ring gear 57. The first gear 87 rotates integrally with the first ring gear 57. The second gear 88 meshes with the first gear 87.

[0050] The configuration of the second planetary gear mechanism 53 is the same as that of the second planetary gear mechanism 53 of the motor drive assembly 12A according to the first embodiment. However, the second sun gear 65 is fixed to the second gear 88. The second sun gear 65 rotates integrally with the second gear 88. The second carrier 68 is fixed to the sprocket 25. The sprocket 25 rotates integrally with the second carrier 68. The second planetary gear mechanism 53 reduces the rotation of the parallel shaft gear 86 and transmits it to the sprocket 25. Other configurations of the motor drive assembly 12C according to the third embodiment are the same as those of the motor drive assembly 12A according to the first embodiment.

[0051] Also in the motor drive assembly 12C according to the third embodiment, similar to the motor drive assembly 12A according to the first embodiment, during an emergency brake, the clutch 46 is disengaged, so that the motor 40 is released from the final drive assembly 22. Therefore, the braking distance of the working machine 1 during an emergency brake can be shortened because the inertia moment of the motor 40 is not transmitted to the final drive assembly 22.

[0052] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention.

[0053] The work machine 1 is not limited to a bulldozer, but may be other machines such as an excavator, wheel loader, grader, or dump truck. The configuration of the travel devices 4 and 5 is not limited to that of the above embodiment and may be changed. For example, the travel devices 4 and 5 may include tires instead of tracks. The structure or arrangement of the motor assembly 21 and the final drive assembly 22 is not limited to that of the above embodiment and may be changed. For example, the motor assembly 21 is not limited to an electric motor, but may be a hydraulic motor.

[0054] In the motor drive assembly 12A according to the first embodiment, if the torque applied to the clutch 46 exceeds a predetermined value, the controller 19 may control the hydraulic pressure of the clutch oil chamber 80 so that the clutch discs 47A and 47B slide against each other. As a result, similar to the motor drive assembly 12B according to the second embodiment, when excessive torque is applied to the final drive assembly 22, the clutch 46 releases the motor 40 from the final drive assembly 22. This reduces the load on the rotating elements of the final drive assembly 22.

[0055] In the motor drive assembly 12C according to the third embodiment, the clutch 46 may have a biasing member 85 similar to that of the motor drive assembly 12B according to the second embodiment. In that case, similar to the motor drive assembly 12B according to the second embodiment, when excessive torque is applied to the final drive assembly 22, the clutch 46 releases the motor 40 from the final drive assembly 22. This reduces the load on the rotating elements of the final drive assembly 22.

[0056] According to this disclosure, in a motor drive assembly for a work machine, the influence on the final drive assembly due to the motor's moment of inertia is reduced.

[0057] 2: Body, 4: Running gear, 12A, 12B, 12C: Motor drive assembly, 22: Final drive assembly, 40: Motor, 46: Clutch, 51: First planetary gear mechanism, 52: Brake

Claims

1. A motor drive assembly for a work machine, comprising: a motor; a final drive assembly including a motor; a gear mechanism for transmitting rotation from the motor; and a brake for braking the rotation from the motor; and a clutch connected to the motor and the final drive assembly, which connects the motor to the final drive assembly when engaged and releases the motor from the final drive assembly when disengaged.

2. The motor drive assembly according to claim 1, wherein the clutch releases the motor from the final drive assembly when the brake is braking the rotation from the motor.

3. The motor drive assembly according to claim 1, wherein the clutch releases the motor from the final drive assembly when the power supply to the work machine is lost.

4. The motor drive assembly according to claim 1, wherein the brake is a negative brake that brakes the rotation from the motor when no hydraulic pressure is acting on the brake, and the clutch releases the motor from the final drive assembly when no hydraulic pressure is acting on the clutch.

5. The motor drive assembly according to claim 1, wherein the clutch includes a biasing member, and the motor is connected to the final drive assembly by the biasing force of the biasing member.

6. The motor drive assembly according to claim 1, wherein the clutch releases the motor from the final drive assembly when the torque applied to the clutch is greater than or equal to a predetermined value.

7. The motor drive assembly according to claim 1, wherein the clutch includes a biasing member and a clutch disc, and the motor is connected to the final drive assembly by the biasing force of the biasing member, and the clutch is configured such that the clutch disc slips when the torque applied to the clutch is greater than or equal to a predetermined value, wherein the diameter of the clutch disc, the friction coefficient of the clutch disc, and the biasing force of the biasing member are set to such an extent.

8. The motor drive assembly according to claim 1, further comprising a controller for controlling the clutch, wherein the clutch connects the motor to the final drive assembly by hydraulic pressure, and the controller controls the hydraulic pressure of the clutch to release the motor from the final drive assembly when the torque applied to the clutch is greater than or equal to a predetermined value.

9. A motor drive assembly for a work machine, comprising: a motor; a final drive assembly driven by the motor; and a clutch provided between the motor and the final drive assembly, which slips when a torque exceeding a predetermined magnitude is applied.

10. A work machine comprising a vehicle body and a running device that supports the vehicle body, wherein the running device includes the motor drive assembly described in claim 1.

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