Electric drive system for work machine and work machine

Abstract

This electric drive system for a work machine includes an electric motor, drive wheels, a first gear set, a second gear set, and a brake. The first gear set includes a pair of first parallel-shaft gears and is disposed between the electric motor and the drive wheels. The second gear set is disposed between the first gear set and the drive wheels. The brake is disposed between the first gear set and the second gear set.

Description

Electric drive system for working machine and working machine

[0001] The present disclosure relates to an electric drive system for a working machine and a working machine.

[0002] The electric drive system for a working machine includes a motor and a final drive assembly. The final drive assembly is connected to the motor. For example, the electric drive system 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. Rotation from the motor is transmitted to the planetary gear mechanism via the brake, decelerated, and then transmitted to the sprocket.

[0003] U.S. Pat. No. 12084132

[0004] In electric drive systems, it is desired to achieve size reduction and obtain a large reduction ratio. An object of the present disclosure is to reduce the size of an electric drive system for a working machine and obtain a large reduction ratio.

[0005] The electric drive system for a working machine according to a first aspect of the present disclosure includes an electric motor, a drive wheel, a first gear set, a second gear set, and a brake. The first gear set includes a pair of first parallel shaft gears, and is disposed between the electric motor and the drive wheel. The second gear set is disposed between the first gear set and the drive wheel. The brake is disposed between the first gear set and the second gear set.

[0006] The electric drive system for a working machine according to a second aspect of the present disclosure includes a motor, a drive wheel, a first gear set, a second gear set, and a brake. The first gear set includes a pair of first parallel shaft gears, and is disposed between the motor and the drive wheel. The second gear set is disposed between the first gear set and the drive wheel. The brake is disposed between the first gear set and the second gear set.

[0007] A working machine according to another aspect of the present disclosure includes a vehicle body, a traveling device, and the electric drive system according to the first aspect or the second aspect described above. The traveling device supports the vehicle body. The electric drive system drives the traveling device.

[0008] According to this disclosure, electric drive systems for industrial machinery can be miniaturized while achieving a large reduction ratio.

[0009] This is a perspective view of a work machine according to an embodiment. This is a skeleton diagram of an electric drive system. This is a skeleton diagram of an electric drive system according to a modified example.

[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. 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 gear 4 supports the vehicle body 2. The left running gear 4 includes a track 11 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 wrapped around a drive wheel 21. The drive wheel 21 is a sprocket. The axis of the drive wheel 21 extends in the left-right direction of the work machine 1. In the following description, the direction parallel to the axis is defined as the axial direction. Also, the direction away from the centerline of the vehicle body of the work machine 1 in the axial direction is defined as the outward direction in the axial direction, and the opposite direction is defined as the inward direction in the axial direction. The configuration of the right running gear is the same as that of the left running gear 4, so its description is omitted.

[0012] The work machine 1 is equipped with an electric drive system 12. Figure 2 is a skeleton diagram of the electric drive system 12. The electric drive system 12 includes a motor 20, the aforementioned drive wheel 21, a first parallel shaft gear set 22, a first output shaft 23, a brake 24, a second parallel shaft gear set 25, and a planetary gear set 27. In this embodiment, the motor 20 is an electric motor 20. The first parallel shaft gear set 22, the first output shaft 23, the brake 24, the second parallel shaft gear set 25, and the planetary gear set 27 are arranged in the axial direction.

[0013] The first parallel-axis gear set 22 is a reduction gear. The first parallel-axis gear set 22 is located outside the motor 20 in the axial direction. The first parallel-axis gear set 22 includes a pair of first parallel-axis gears 31 and 32. The pair of first parallel-axis gears 31 and 32 have their axes parallel to each other. The pair of first parallel-axis gears 31 and 32 includes a first input gear 31 and a first output gear 32. The first input gear 31 is connected to the motor 20. The first input gear 31 is rotated by the motor 20. The first output gear 32 meshes with the first input gear 31. The first output shaft 23 is connected to the first output gear 32. The first output shaft 23 rotates integrally with the first output gear 32.

[0014] The brake 24 is located outside the first parallel shaft gear set 22 in the axial direction. The axis of the brake 24 is eccentrically positioned from the axis of the motor 20. The brake 24 is located between the first parallel shaft gear set 22 and the second parallel shaft gear set 25 in the axial direction. The brake 24 brakes the first output shaft 23 by engaging with it.

[0015] The second parallel shaft gear set 25 is a reduction gear. The second parallel shaft gear set 25 is located outside the brake 24 in the axial direction. The second parallel shaft gear set 25 is located between the brake 24 and the planetary gear set 27 in the axial direction. The second parallel shaft gear set 25 includes a pair of second parallel shaft gears 33 and 34. The pair of second parallel shaft gears 33 and 34 have their axes parallel to each other. The pair of second parallel shaft gears 33 and 34 includes a second input gear 33 and a second output gear 34. The second input gear 33 is connected to the first output shaft 23. The second input gear 33 rotates integrally with the first output shaft 23. The second output gear 34 meshes with the second input gear 33. The second output shaft 26 is connected to the second output gear 34. The second output shaft 26 rotates integrally with the second output gear 34.

[0016] The planetary gear set 27 is a reduction gear. The planetary gear set 27 is located outside the second parallel shaft gear set 25 in the axial direction. The planetary gear set 27 is located between the second parallel shaft gear set 25 and the drive wheel 21 in the axial direction. The axis of the planetary gear set 27 is eccentrically positioned from the axis of the motor 20. The axis of the planetary gear set 27 is eccentrically positioned from the axis of the brake 24. The planetary gear set 27 is located coaxially with the drive wheel 21.

[0017] The planetary gear set 27 includes a sun gear 41, a planetary gear 42, a carrier 43, and a ring gear 44. The sun gear 41 is connected to the second output shaft 26. The sun gear 41 rotates integrally with the second output shaft 26. The planetary gear 42 meshes with the sun gear 41. The planetary gear 42 is capable of revolving around the sun gear 41. The planetary gear 42 is supported by the carrier 43 so as to be rotatable. The ring gear 44 meshes with the planetary gear 42. The ring gear 44 is fixed so as not to rotate. The carrier 43 is connected to the drive wheel 21. The drive wheel 21 is rotatable with the carrier 43.

[0018] In the electric drive system 12 described above, the rotation of the motor 20 is transmitted to the first output shaft 23 via a pair of first parallel shaft gears 31 and 32 of the first parallel shaft gear set 22. The rotation of the first output shaft 23 is transmitted to the second output shaft 26 via a pair of second parallel shaft gears 33 and 34 of the second parallel shaft gear set 25. The rotation of the second output shaft 26 is transmitted to the drive wheel 21 via the sun gear 41, planetary gear 42, and carrier 43. As a result, the drive wheel 21 rotates.

[0019] In the electric drive system 12 according to this embodiment described above, a first parallel shaft gear set 22, a brake 24, and a second parallel shaft gear set 25 are arranged on the output side of the motor 20. As a result, the electric drive system 12 for the work machine can be made smaller and a large reduction ratio can be obtained.

[0020] 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.

[0021] 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 running gear 4 is not limited to that of the above embodiment and may be changed. For example, the running gear 4 may include tires instead of tracks. The drive wheels 21 are not limited to sprockets, but may be wheels and tires.

[0022] The structure or arrangement of the electric drive system 12 is not limited to that of the embodiment described above and may be modified. For example, Figure 3 is a skeleton diagram of an modified electric drive system 12. As shown in Figure 3, the electric drive system 12 may include a planetary gear set 28 (hereinafter referred to as the first planetary gear set 28) instead of the second parallel shaft gear set 25 of the embodiment described above. Hereinafter, the planetary gear mechanism 27 described above and its components, the sun gear 41, planetary gear 42, carrier 43, and ring gear 44, will be referred to as the second planetary gear set 27, the second sun gear 41, the second planetary gear 42, the second carrier 43, and the second ring gear 44, respectively.

[0023] The first planetary gear set 28 is a reduction gear. The first planetary gear set 28 includes a first sun gear 51, a first planetary gear 52, a first carrier 53, and a first ring gear 54. The first sun gear 51 is connected to the first output shaft 23. The first sun gear 51 rotates integrally with the first output shaft 23. The first planetary gear 52 meshes with the first sun gear 51. The first planetary gear 52 is capable of revolving around the first sun gear 51. The first planetary gear 52 is supported by the first carrier 53 so as to be rotatable. The first ring gear 54 meshes with the first planetary gear 52. The first ring gear 54 is fixed so as not to rotate. The first carrier 53 is connected to the second output shaft 26. The configuration of the second planetary gear set 27 is the same as that of the embodiment described above.

[0024] In the modified electric drive system 12, the rotation of the motor 20 is transmitted to the first output shaft 23 via a pair of first parallel shaft gears 31 and 32 of the first parallel shaft gear set 22. The rotation of the first output shaft 23 is transmitted to the second output shaft 26 via the first sun gear 51, first planetary gear 52, and first carrier 53 of the first planetary gear set 28. The rotation of the second output shaft 26 is transmitted to the drive wheel 21 via the second sun gear 41, second planetary gear 42, and second carrier 43 of the second planetary gear set 27. As a result, the drive wheel 21 rotates.

[0025] According to this disclosure, electric drive systems for industrial machinery can be miniaturized while achieving a large reduction ratio.

[0026] 1: Working machine, 2: Body, 4: Running gear, 12: Electric drive system, 20: Motor, 21: Drive wheel, 22: First parallel shaft gear set, 23: First output shaft, 24: Brake, 25: Second parallel shaft gear set, 26: Second output shaft, 31, 32: First parallel shaft gear, 33, 34: Second parallel shaft gear, 41: Second sun gear, 42: Second planetary gear, 43: Second carrier, 44: Second ring gear, 51: First sun gear, 52: First planetary gear, 53: First carrier, 54: First ring gear

Claims

1. An electric drive system for a work machine, comprising: an electric motor; a drive wheel; a first gear set including a pair of first parallel shaft gears, disposed between the electric motor and the drive wheel; a second gear set disposed between the first gear set and the drive wheel; and a brake disposed between the first gear set and the second gear set.

2. The electric drive system according to claim 1, further comprising an output shaft connected to the first gear set, wherein the brake is configured to engage with the output shaft.

3. The electric drive system according to claim 1, wherein the second gear set includes a planetary gear mechanism.

4. The electric drive system according to claim 1, further comprising a third gear set disposed between the brake and the second gear set.

5. The electric drive system according to claim 1, wherein the third gear set includes a pair of second parallel shaft gears.

6. The electric drive system according to claim 5, further comprising: a first output shaft connecting the first gear set and the third gear set; and a second output shaft connecting the third gear set and the second gear set, wherein the second gear set includes: a sun gear connected to the second output shaft; a planetary gear meshing with the sun gear; a ring gear meshing with the planetary gear; and a carrier connected to the planetary gear.

7. The electric drive system according to claim 6, wherein the drive wheels are connected to the carrier.

8. The electric drive system according to claim 1, wherein the third gear set includes a planetary gear mechanism.

9. The electric drive system according to claim 8, further comprising: a first output shaft connecting the first gear set and the third gear set; and a second output shaft connecting the third gear set and the second gear set, wherein the third gear set includes: a first sun gear connected to the first output shaft; a first planetary gear meshing with the first sun gear; a first ring gear meshing with the first planetary gear; and a first carrier connected to the first planetary gear; and the second gear set includes: a second sun gear connected to the first carrier via the second output shaft; a second planetary gear meshing with the second sun gear; a second ring gear meshing with the second planetary gear; and a second carrier connected to the second planetary gear.

10. The electric drive system according to claim 9, wherein the drive wheel is connected to the second carrier.

11. A work machine comprising: a vehicle body; a running gear that supports the vehicle body; and an electric drive system that drives the running gear.

12. An electric drive system for a work machine, comprising: a motor; a drive wheel; a first gear set including a pair of first parallel shaft gears, disposed between the motor and the drive wheel; a second gear set disposed between the first gear set and the drive wheel; and a brake disposed between the first gear set and the second gear set.

13. The electric drive system according to claim 12, further comprising an output shaft connected to the first gear set, wherein the brake is configured to engage with the output shaft.

14. The electric drive system according to claim 12, wherein the second gear set includes a planetary gear mechanism.

15. The electric drive system according to claim 12, further comprising a third gear set disposed between the brake and the second gear set.

16. The electric drive system according to claim 12, wherein the third gear set includes a pair of second parallel shaft gears.

17. The electric drive system according to claim 16, further comprising: a first output shaft connecting the first gear set and the third gear set; and a second output shaft connecting the third gear set and the second gear set, wherein the second gear set includes: a sun gear connected to the second output shaft; a planetary gear meshing with the sun gear; a ring gear meshing with the planetary gear; and a carrier connected to the planetary gear.

18. The electric drive system according to claim 17, wherein the drive wheels are connected to the carrier.

19. The electric drive system according to claim 12, wherein the third gear set includes a planetary gear mechanism.

20. A work machine comprising: a vehicle body; a running gear that supports the vehicle body; and an electric drive system that drives the running gear.

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