Work machine drive system and work machine

Abstract

According to the present invention, a first motor is connected to a first planetary gear mechanism and inputs drive force to the first planetary gear mechanism, a second motor is connected to a second planetary gear mechanism and inputs drive force to the second planetary gear mechanism, and a third motor is offset from one of the first motor and the second motor and inputs drive force to the first planetary gear mechanism and the second planetary gear mechanism.

Description

Drive System for Work Machine and Work Machine

[0001] The present disclosure relates to a drive system for a work machine and a work machine.

[0002] Some drive systems for work machines include a plurality of motors and a plurality of planetary gear mechanisms. For example, the drive system of Patent Document 1 includes three motors and three planetary gear mechanisms. Each motor is respectively connected to a corresponding planetary gear mechanism. The central planetary gear mechanism is connected to each of the left and right planetary gear mechanisms. The left and right planetary gear mechanisms are each connected to an output shaft.

[0003] US Patent Publication No. 2007 / 0049439

[0004] In drive systems, it is desired to simplify the structure and achieve a large reduction ratio. An object of the present disclosure is to simplify the drive system for a work machine and achieve a large reduction ratio.

[0005] A drive system for a work machine according to one aspect of the present disclosure includes a left drive wheel, a right drive wheel, a first planetary gear mechanism, a second planetary gear mechanism, a first motor, a second motor, and a third motor. The first motor is connected to the first planetary gear mechanism and inputs driving force to the first planetary gear mechanism. The second motor is connected to the second planetary gear mechanism and inputs driving force to the second planetary gear mechanism. The third motor is arranged eccentrically from either one of the first motor and the second motor, and inputs driving force to the first planetary gear mechanism and the second planetary gear mechanism.

[0006] A work machine according to another aspect of the present disclosure includes a vehicle body, a traveling device that supports the vehicle body, and the drive system described above. The drive system drives the traveling device.

[0007] According to the present disclosure, the structure of the drive system for a work machine is simplified, and a large reduction ratio can be obtained.

[0008] This is a perspective view of a work machine according to an embodiment. This is a skeleton diagram of the drive system according to the first embodiment. This is a side view showing the arrangement of motors in the drive system. This is a rear view showing the arrangement of motors in the drive system. This is a top view showing the arrangement of motors in the drive system. This is a skeleton diagram of the drive system according to the second embodiment. This is a skeleton diagram of the drive system according to the third embodiment.

[0009] 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. Note that the right traveling device is not shown in Figure 1. 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 on the body 2. The working machine 3 includes a blade 8. The traveling device 4 supports the body 2.

[0010] The left-side running gear 4 includes a track 11 and a track frame 12. The track frame 12 supports the track 11 via several road wheels (not shown) and idlers. Although not shown, the right-side running gear also includes a track and a track frame, similar to the left-side running gear 4.

[0011] The work machine 1 includes a drive system 10. The drive system 10 is supported by the vehicle body 2 and the left and right running gears 4. The drive system 10 includes a left drive wheel 21 and a right drive wheel 31 (see Figure 2). The track 11 of the left running gear 4 is wrapped around the left drive wheel 21. The track of the right running gear is wrapped around the right drive wheel 31. The left drive wheel 21 and the right drive wheel 31 are sprockets. The axes of the left drive wheel 21 and the right drive wheel 31 extend in the left-right direction of the work machine 1. In the following description, the direction parallel to the axes of the left drive wheel 21 and the right drive wheel 31 is defined as the axial direction. Furthermore, 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.

[0012] Figure 2 is a skeleton diagram of the drive system 10 according to the first embodiment. As shown in Figure 2, the drive system 10 comprises a first motor M1, a second motor M2, a third motor M3, the left drive wheel 21 described above, a first planetary gear mechanism 22, a first intermediate shaft 23, a first brake 24, a first final drive assembly 25, the right drive wheel 31 described above, a second planetary gear mechanism 32, a second intermediate shaft 33, a second brake 34, and a second final drive assembly 35.

[0013] The first to third motors M1-M3 are positioned between the left drive wheel 21 and the right drive wheel 31 in the axial direction. The first to third motors M1-M3 are electric motors. Figure 3 is a side view showing the arrangement of the first to third motors M1-M3. Figure 4 is a rear view showing the arrangement of the first to third motors M1-M3. Figure 5 is a top view showing the arrangement of the first to third motors M1-M3. As shown in Figures 3 to 5, the third motor M3 is positioned eccentrically from the first motor M1 and the second motor M2. The first motor M1 and the second motor M2 are positioned eccentrically from each other. As shown in Figure 5, in a top view of the vehicle, the first motor M1 and the second motor M2 are positioned overlapping with the third motor M3. As shown in Figure 4, in a rear view of the vehicle, the first motor M1 and the second motor M2 are positioned overlapping with each other.

[0014] As shown in Figure 2, the third motor M3 includes a first rotation shaft 27 and a second rotation shaft 37. The third motor M3 is arranged such that the rotation shafts 27 and 37 are parallel to each other in the axial direction. The first rotation shaft 27 and the second rotation shaft 37 rotate together as a single unit. The first rotation shaft 27 and the second rotation shaft 37 may be a single unit. Alternatively, the first rotation shaft 27 and the second rotation shaft 37 may be separate units.

[0015] The first rotating shaft 27 extends to the left from the third motor M3. The second rotating shaft 37 extends to the right from the third motor M3. The left drive wheel 21 and the right drive wheel 31 are rotated by the driving force from the first to third motors M1-M3. The track 11 of the left running gear 4 is wrapped around the left drive wheel 21. The track of the right running gear is wrapped around the right drive wheel 31.

[0016] The first planetary gear mechanism 22 is a reduction gear. The first planetary gear mechanism 22 is located to the left of the third motor M3 in the axial direction. The first planetary gear mechanism 22 is located between the third motor M3 and the first brake 24 in the axial direction. The first planetary gear mechanism 22 is located coaxially with the third motor M3. The first planetary gear mechanism 22 includes a first sun gear 41, a first planetary gear 42, a first carrier 43, and a first ring gear 44.

[0017] The first sun gear 41 is connected to the first rotating shaft 27 of the third motor M3. The first sun gear 41 rotates integrally with the first rotating shaft 27. The first planetary gear 42 meshes with the first sun gear 41. The first planetary gear 42 is supported by the first carrier 43 so that it can revolve around the first sun gear 41. The first planetary gear 42 is capable of rotating on its own axis. The first carrier 43 rotates together with the first planetary gear 42. The internal teeth of the first ring gear 44 mesh with the first planetary gear 42. The first ring gear 44 rotates due to the rotation of the first planetary gear 42.

[0018] The first motor M1 is connected to the first planetary gear mechanism 22. The first motor M1 inputs driving force to the first planetary gear mechanism 22. More specifically, the first motor M1 is connected to the first motor gear 45. The first motor gear 45 is rotated by the first motor M1. The first motor gear 45 meshes with the external teeth of the first ring gear 44. The first motor M1 is connected to the first ring gear 44 via the first motor gear 45. The first motor M1 inputs driving force to the first ring gear 44.

[0019] The first intermediate shaft 23 is arranged coaxially with the third motor M3. The first intermediate shaft 23 is connected to the first planetary gear mechanism 22 and the first final drive assembly 25. The first intermediate shaft 23 is connected to the first carrier 43 of the first planetary gear mechanism 22. The first intermediate shaft 23 rotates integrally with the first carrier 43.

[0020] The first brake 24 is positioned in the axial direction between the first final drive assembly 25 and the first planetary gear mechanism 22. In the braking state, the first brake 24 engages with the first intermediate shaft 23, thereby braking the first intermediate shaft 23. In the non-braking state, the first brake 24 releases the first intermediate shaft 23.

[0021] The first final drive assembly 25 is positioned eccentrically from the third motor M3. The first final drive assembly 25 is positioned to the left of the first intermediate shaft 23. In the axial direction, the first final drive assembly 25 is positioned between the left drive wheel 21 and the first planetary gear mechanism 22. The first final drive assembly 25 is positioned between the left drive wheel 21 and the first intermediate shaft 23 in the axial direction. The first final drive assembly 25 receives driving force from the first planetary gear mechanism 22 and outputs driving force to the left drive wheel 21.

[0022] The first final drive assembly 25 includes a pair of parallel-axis gears 28A and 28B and a planetary gear mechanism 29. The pair of parallel-axis gears 28A and 28B are a reduction gear. The axes of the pair of parallel-axis gears 28A and 28B are parallel to each other. The pair of parallel-axis gears 28A and 28B mesh with each other. Parallel-axis gear 28A is connected to the first intermediate shaft 23. Parallel-axis gear 28A rotates integrally with the first intermediate shaft 23.

[0023] The planetary gear mechanism 29 is a reduction gear. The planetary gear mechanism 29 is located to the left of a pair of parallel shaft gears 28A and 28B. The planetary gear mechanism 29 is located eccentrically from the third motor M3. The planetary gear mechanism 29 includes a sun gear 46, a planetary gear 47, a carrier 48, and a ring gear 49. The sun gear 46 is connected to the parallel shaft gear 28B. The sun gear 46 rotates integrally with the parallel shaft gear 28B. The planetary gear 47 meshes with the sun gear 46. The planetary gear 47 is capable of orbiting the sun gear 46. The planetary gear 47 is supported by the carrier 48 so that it can orbit the sun gear 46. The ring gear 49 meshes with the planetary gear 47. The ring gear 49 is fixed so as not to rotate. The carrier 48 rotates due to the orbit of the planetary gear 47. The left drive wheel 21 is connected to the carrier 48. The left drive wheel 21 rotates as the carrier 48 rotates.

[0024] The right drive wheel 31, the second planetary gear mechanism 32, the second intermediate shaft 33, the second brake 34, and the second final drive assembly 35 have a structure that is symmetrical to that of the left drive wheel 21, the first planetary gear mechanism 22, the first intermediate shaft 23, the first brake 24, and the first final drive assembly 25, respectively.

[0025] The second planetary gear mechanism 32 is a reduction gear. The second planetary gear mechanism 32 is located to the right of the third motor M3 in the axial direction. The second planetary gear mechanism 32 is located between the third motor M3 and the second brake 34 in the axial direction. The second planetary gear mechanism 32 is located coaxially with the third motor M3. The second planetary gear mechanism 32 includes a second sun gear 51, a second planetary gear 52, a second carrier 53, and a second ring gear 54.

[0026] The second sun gear 51 is connected to the second rotating shaft 37 of the third motor M3. The second sun gear 51 rotates integrally with the second rotating shaft 37. The second planetary gear 52 meshes with the second sun gear 51. The second planetary gear 52 is supported by the second carrier 53 so that it can revolve around the second sun gear 51. The second planetary gear 52 is capable of rotating on its own axis. The second carrier 53 rotates together with the second planetary gear 52. The internal teeth of the second ring gear 54 mesh with the second planetary gear 52. The second ring gear 54 rotates due to the rotation of the second planetary gear 52.

[0027] The second motor M2 is connected to the second planetary gear mechanism 32. The second motor M2 inputs driving force to the second planetary gear mechanism 32. More specifically, the second motor M2 is connected to the second motor gear 55. The second motor gear 55 is rotated by the second motor M2. The second motor gear 55 meshes with the external teeth of the second ring gear 54. The second motor M2 is connected to the second ring gear 54 via the second motor gear 55. The second motor M2 inputs driving force to the second ring gear 54.

[0028] The second intermediate shaft 33 is arranged coaxially with the third motor M3. The second intermediate shaft 33 is connected to the second planetary gear mechanism 32 and the second final drive assembly 35. The second intermediate shaft 33 is connected to the second carrier 53 of the second planetary gear mechanism 32. The second intermediate shaft 33 rotates integrally with the second carrier 53.

[0029] The second brake 34 is positioned axially between the second final drive assembly 35 and the second planetary gear mechanism 32. In the braking state, the second brake 34 engages with the second intermediate shaft 33, thereby braking the second intermediate shaft 33. In the non-braking state, the second brake 34 releases the second intermediate shaft 33.

[0030] The second final drive assembly 35 is positioned eccentrically from the third motor M3. The second final drive assembly 35 is positioned to the right of the second intermediate shaft 33. In the axial direction, the second final drive assembly 35 is positioned between the right drive wheel 31 and the second planetary gear mechanism 32. The second final drive assembly 35 is positioned between the right drive wheel 31 and the second intermediate shaft 33 in the axial direction. The second final drive assembly 35 receives driving force from the second planetary gear mechanism 32 and outputs driving force to the right drive wheel 31.

[0031] The second final drive assembly 35 includes a pair of parallel-axis gears 38A and 38B and a planetary gear mechanism 39. The pair of parallel-axis gears 38A and 38B are a reduction gear. The axes of the pair of parallel-axis gears 38A and 38B are parallel to each other. The pair of parallel-axis gears 38A and 38B mesh with each other. Parallel-axis gear 38A is connected to the second intermediate shaft 33. Parallel-axis gear 38A rotates integrally with the second intermediate shaft 33.

[0032] The planetary gear mechanism 39 is a reduction gear. The planetary gear mechanism 39 is located to the right of a pair of parallel shaft gears 38A and 38B. The planetary gear mechanism 39 is located eccentrically from the third motor M3. The planetary gear mechanism 39 includes a sun gear 56, a planetary gear 57, a carrier 58, and a ring gear 59. The sun gear 56 is connected to the parallel shaft gear 38B. The sun gear 56 rotates integrally with the parallel shaft gear 38B. The planetary gear 57 meshes with the sun gear 56. The planetary gear 57 is capable of orbiting the sun gear 56. The planetary gear 57 is supported by the carrier 58 so that it can orbit the sun gear 56. The ring gear 59 meshes with the planetary gear 57. The ring gear 59 is fixed so as not to rotate. The carrier 58 rotates due to the orbit of the planetary gear 57. The right drive wheel 31 is connected to the carrier 58. The right drive wheel 31 rotates as the carrier 58 rotates.

[0033] When the work machine 1 is moving, the third motor M3 inputs driving force to the first planetary gear mechanism 22 and the second planetary gear mechanism 32. A portion of the driving force from the third motor M3 and the driving force from the first motor M1 are transmitted to the left drive wheel 21 via the first planetary gear mechanism 22, the first intermediate shaft 23, and the first final drive assembly 25. As a result, the left drive wheel 21 rotates. A portion of the driving force from the third motor M3 and the driving force from the second motor M2 are transmitted to the right drive wheel 31 via the second planetary gear mechanism 32, the second intermediate shaft 33, and the second final drive assembly 35. As a result, the right drive wheel 31 rotates.

[0034] In the work machine 1 according to this embodiment described above, the structure of the drive system 10 is simplified, and a large reduction ratio can be obtained.

[0035] 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.

[0036] 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 and 31 are not limited to sprockets, but may be wheels and tires.

[0037] The structure or arrangement of the drive system 10 is not limited to that of the above embodiment and may be modified. For example, the motors M1-M3 may be hydraulic motors. The configuration or arrangement of the final drive assemblies 25 and 35 is not limited to that of the above embodiment and may be modified. For example, the final drive assemblies 25 and 35 may include other gear sets such as parallel shaft gears instead of the planetary gear mechanisms 29 and 39.

[0038] Figure 6 is a skeleton diagram of the drive system 10 according to the second embodiment. As shown in Figure 6, the drive system 10 may include a pair of first parallel shaft gears 61, 62 and a pair of second parallel shaft gears 63, 64. The pair of first parallel shaft gears 61, 62 and the pair of second parallel shaft gears 63, 64 may be a reduction gear. The pair of first parallel shaft gears 61, 62 are arranged between the third motor M3 and the first planetary gear mechanism 22. The pair of second parallel shaft gears 63, 64 are arranged between the third motor M3 and the second planetary gear mechanism 32.

[0039] The first parallel shaft gear 61 is connected to the first rotating shaft 27 of the third motor M3. The first parallel shaft gear 61 rotates integrally with the first rotating shaft 27. The first parallel shaft gear 62 is connected to the first sun gear 41. The first sun gear 41 rotates integrally with the first parallel shaft gear 62. The second parallel shaft gear 63 is connected to the second rotating shaft 37 of the third motor M3. The second parallel shaft gear 63 rotates integrally with the second rotating shaft 37. The second parallel shaft gear 64 is connected to the second sun gear 51. The second sun gear 51 rotates integrally with the second parallel shaft gear 64. The other configurations are the same as those of the drive system 10 according to the first embodiment.

[0040] Figure 7 is a skeleton diagram of the drive system 10 according to the third embodiment. As shown in Figure 7, in the drive system 10 according to the third embodiment, the first motor M1 is connected to the first sun gear 41 via the first motor gear 45. The second motor M2 is connected to the second sun gear 51 via the second motor gear 55. The drive system 10 according to the third embodiment further includes an input shaft 71 and a third planetary gear mechanism 72. The input shaft 71 is arranged coaxially with the third motor M3 and extends through the third motor M3. The input shaft 71 extends through the rotation axis 73 of the third motor M3 and is rotatable relative to the rotation axis 73 of the third motor M3.

[0041] The third planetary gear mechanism 72 is a reduction gear. The third planetary gear mechanism 72 is located axially between the third motor M3 and the second planetary gear mechanism 32. Alternatively, the third planetary gear mechanism 72 may be located axially between the third motor M3 and the first planetary gear mechanism 22. The third planetary gear mechanism 72 is located coaxially with the third motor M3. The third planetary gear mechanism 72 includes a third sun gear 74, a third planetary gear 75, a third carrier 76, and a third ring gear 77.

[0042] The third sun gear 74 is connected to the rotating shaft 73 of the third motor M3. The third sun gear 74 rotates integrally with the rotating shaft 73. The third planetary gear 75 meshes with the third sun gear 74. The third planetary gear 75 is supported by the third carrier 76 so as to be able to revolve around the third sun gear 74. The third planetary gear 75 is able to rotate on its own axis. The third carrier 76 rotates together with the third planetary gear 75. The third ring gear 77 meshes with the third planetary gear 75. The third ring gear 77 is fixed so as not to rotate. The third carrier 76 is connected to the input shaft 71. The third carrier 76 rotates integrally with the input shaft 71. The input shaft 71 is connected to the first ring gear hub 49 and the second ring gear hub 59. The first ring gear hub 49 and the second ring gear hub 59 rotate integrally with the input shaft 71. The first ring gear hub 49 is connected to the first ring gear 44. The second ring gear hub 59 is connected to the second ring gear 54. The other configurations are the same as those of the drive system 10 according to the first embodiment.

[0043] In the drive system 10 according to the third embodiment, the driving force of the third motor M3 is transmitted to the first planetary gear mechanism 22 and the second planetary gear mechanism 32 via the third planetary gear mechanism 72 and the input shaft 71. The driving force is transmitted to the left drive wheel 21 via the first planetary gear mechanism 22 and the first final drive assembly 25, causing the left drive wheel 21 to rotate. The driving force is also transmitted to the right drive wheel 31 via the second planetary gear mechanism 32 and the second final drive assembly 35, causing the right drive wheel 31 to rotate.

[0044] According to the present disclosure, the structure of the drive system for a working machine is simplified, and a large reduction ratio can be obtained.

[0045] 2: vehicle body, 4: traveling device, 10: drive system, 21: left drive wheel, 22: first planetary gear mechanism, 23: first intermediate shaft, 24: first brake, 25: first final drive assembly, 31: right drive wheel, 32: second planetary gear mechanism, 33: second intermediate shaft, 34: second brake, 35: second final drive assembly, 41: first sun gear, 42: first planetary gear, 43: first carrier, 44: first ring gear, 51: second sun gear, 52: second planetary gear, 53: second carrier, 54: second ring gear, 61, 62: pair of first parallel shaft gears, 63, 64: pair of second parallel shaft gears, 74: third sun gear, 75: third planetary gear, 76: third carrier, 77: third ring gear, M1: first motor, M2: second motor, M3: third motor

Claims

1. A drive system for a work machine, comprising: a left drive wheel; a right drive wheel; a first planetary gear mechanism; a second planetary gear mechanism; a first motor connected to the first planetary gear mechanism and inputting driving force to the first planetary gear mechanism; a second motor connected to the second planetary gear mechanism and inputting driving force to the second planetary gear mechanism; and a third motor eccentrically positioned from either the first motor or the second motor and inputting driving force to the first planetary gear mechanism and the second planetary gear mechanism.

2. The drive system according to claim 1, wherein the first motor and the second motor are arranged eccentrically to each other.

3. The drive system according to claim 1, wherein the third motor is arranged eccentrically from the first motor and the second motor.

4. The drive system according to claim 1, comprising: a first final drive assembly that receives a driving force from the first planetary gear mechanism and outputs a driving force to the left drive wheel; and a second final drive assembly that receives a driving force from the second planetary gear mechanism and outputs a driving force to the right drive wheel.

5. The drive system according to claim 4, further comprising: a first brake disposed between the first final drive assembly and the first planetary gear mechanism; and a second brake disposed between the second final drive assembly and the second planetary gear mechanism.

6. The drive system according to claim 4, further comprising: a first intermediate shaft connected to the first final drive assembly; and a second intermediate shaft connected to the second final drive assembly, wherein the first brake engages with the first intermediate shaft and the second brake engages with the second intermediate shaft.

7. The drive system according to claim 1, wherein the first planetary gear mechanism includes a first sun gear, 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, the first motor being connected to the first ring gear via a first motor gear, and the second planetary gear mechanism includes a second sun gear, 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, the second motor being connected to the second ring gear via a second motor gear.

8. The drive system according to claim 1, further comprising: a pair of first parallel-axis gears disposed between the third motor and the first planetary gear mechanism; and a pair of second parallel-axis gears disposed between the third motor and the second planetary gear mechanism.

9. The drive system according to claim 1, wherein the first planetary gear mechanism includes a first sun gear, 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 planetary gear mechanism includes a second sun gear, 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 drive system according to claim 9, wherein the first motor is connected to the first sun gear via a first motor gear, and the second motor is connected to the second sun gear via a second motor gear.

11. The drive system according to claim 1, further comprising a third planetary gear mechanism disposed between the three motors and the second planetary gear mechanism.

12. The drive system according to claim 11, wherein the third planetary gear mechanism includes a third sun gear, a third planetary gear meshing with the third sun gear, a third ring gear meshing with the third planetary gear, and a third carrier connected to the third planetary gear, and the third motor is connected to the third sun gear.

13. The drive system according to claim 12, further comprising an input shaft connected to the third carrier, wherein the first planetary gear mechanism includes a first sun gear, a first planetary gear meshing with the first sun gear, a first ring gear meshing with the first planetary gear, a first carrier connected to the first planetary gear, and a first ring gear hub connected to the first ring gear, wherein the second planetary gear mechanism includes a second sun gear, a second planetary gear meshing with the second sun gear, a second ring gear meshing with the second planetary gear, a second carrier connected to the second planetary gear, and a second ring gear hub connected to the second ring gear, and the input shaft is connected to the first ring gear hub and the second ring gear hub.

14. The drive system according to claim 13, wherein the input shaft is arranged to pass through the third motor.

15. The drive system according to claim 1, wherein the first motor, the second motor, and the third motor are electric motors.

16. The drive system according to claim 1, wherein, in a plan view of the vehicle, the first motor and the second motor are arranged to overlap with the third motor.

17. The drive system according to claim 1, wherein, when viewed from the rear of the vehicle, the first motor and the second motor are arranged to overlap each other.

18. A work machine comprising: a vehicle body; a running device supporting the vehicle body; and a drive system according to claim 1 for driving the running device.

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