Work machine and electric power train unit for work machine

Abstract

This work machine comprises a vehicle body, a travel device, a work equipment, and an electric power train unit. The electric power train unit drives the travel device and the work machine. The electric power train unit includes a transmission, a first electric motor for the travel device, a bracket, and a second electric motor for the work equipment. The transmission includes an input shaft, an output shaft, and a housing. The output shaft is connected to the travel device. The housing houses the input shaft and the output shaft. The first electric motor includes a first output shaft and is attached to the housing. The first output shaft is connected to the input shaft. The bracket is attached to the housing. The second electric motor is attached to the bracket and supported by the housing via the bracket.

Description

Work machine and electric powertrain unit for work machine

[0001] The present disclosure relates to work machines and electric powertrain units for work machines.

[0002] Some work machines are equipped with a travelling device and a working implement. The travelling device includes, for example, tires or tracks. The travelling device is driven to allow the work machine to travel. The working implement includes, for example, a working tool such as a bucket. The working implement is driven to allow the work machine to perform work such as excavation. In recent years, electric motors have come to be used as a drive source for driving the travelling device and the working implement. For example, the work machine disclosed in Patent Document 1 is equipped with a first electric motor for driving the travelling device and a second electric motor for driving the working implement.

[0003] Japanese Patent Application Laid-Open No. 2006-233843

[0004] In the above-described work machine, a large space is required within the vehicle body to arrange the first electric motor and the second electric motor. This results in an increased vehicle size. Furthermore, separate structures are required to mount the first electric motor and the second electric motor within the vehicle body. Therefore, it is preferable to appropriately arrange the first electric motor and the second electric motor. An object of the present disclosure is to reduce the vehicle body size in a work machine equipped with multiple electric motors.

[0005] A work machine according to one aspect of the present disclosure includes a vehicle body, a travel device, a work implement, and an electric powertrain unit. The travel device is attached to the vehicle body and drives the vehicle body. The work implement is movably connected to the vehicle body. The electric powertrain unit drives the travel device and the work machine. The electric powertrain unit includes a transmission, a first electric motor for the travel device, a bracket, and a second electric motor for the work implement. The transmission includes an input shaft, an output shaft, and a housing. The output shaft is connected to the travel device. The housing accommodates the input shaft and the output shaft. The first electric motor includes a first output shaft and is attached to the housing. The first output shaft is connected to the input shaft. The bracket is attached to the housing. The second electric motor is attached to the bracket and supported by the housing via the bracket.

[0006] An electric powertrain unit for a work machine according to another aspect of the present disclosure includes a transmission, a first electric motor, a bracket, a second electric motor, and a hydraulic pump. The transmission includes an input shaft, an output shaft, and a housing. The housing accommodates the input shaft and the output shaft. The first electric motor includes a first output shaft and is attached to the housing. The first output shaft is connected to the input shaft. The bracket is attached to the housing. The second electric motor includes a second output shaft and is attached to the bracket and supported by the housing via the bracket. The hydraulic pump is connected to the second output shaft.

[0007] According to the present disclosure, the first electric motor is attached to a housing of the transmission, and the second electric motor is attached to the housing of the transmission via a bracket. This allows the first electric motor, the second electric motor, and the transmission to be unitized as an electric powertrain unit. This allows the first electric motor and the second electric motor to be arranged compactly. Furthermore, structures for mounting the first electric motor and the second electric motor within the vehicle body are either not required or can be made smaller. This allows the vehicle body of the work machine to be made smaller.

[0008] FIG. 1 is a side view of a work machine according to an embodiment. FIG. 2 is a block diagram showing the configuration of a drive system mounted on the work machine. FIG. 3 is a perspective view of an electric powertrain unit. FIG. 4 is a side view of the electric powertrain unit. FIG. 5 is a top view of the electric powertrain unit. FIG. 6 is an exploded perspective view of the electric powertrain unit. FIG. 7 is a perspective view of a transmission and a motor bracket. FIG. 8 is a perspective view of the transmission and the motor bracket. FIG. 9 is a rear view of the transmission and the motor bracket. FIG. 10 is a side view of an electric powertrain unit mounted on a vehicle body. FIG. 11 is a top view of an electric powertrain unit mounted on a vehicle body. FIG. 12 is a front view of an electric powertrain unit mounted on a vehicle body. FIG. 13 is a top view of an electric powertrain unit mounted on a vehicle body according to a modified example. FIG. 14 is a perspective view of an electric powertrain unit according to a modified example.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a side view of a work machine 1 according to an embodiment of the present disclosure. The work machine 1 according to this embodiment is an electric wheel loader. As shown in Fig. 1, the work machine 1 includes a vehicle body 2, a work implement 5, and a traveling device 6.

[0010] The vehicle body 2 includes a front vehicle body 3 and a rear vehicle body 4. The rear vehicle body 4 is connected to the front vehicle body 3 so as to be able to turn left and right. A driver's cab 7, a hydraulic oil tank 8, and a power room 9 are arranged in the rear vehicle body 4. The hydraulic oil tank 8 is arranged behind the driver's cab 7. The power room 9 is arranged behind the hydraulic oil tank 8. A steering cylinder 15 is connected to the front vehicle body 3 and the rear vehicle body 4. The steering cylinder 15 is a hydraulic cylinder. The extension and contraction of the steering cylinder 15 causes the front vehicle body 3 to turn left and right relative to the rear vehicle body 4.

[0011] The traveling device 6 is attached to the vehicle body 2. The traveling device 6 causes the work machine 1 to travel. Figure 2 is a block diagram showing the configuration of a drive system 10 mounted on the work machine 1. As shown in Figures 1 and 2, the traveling device 6 includes front wheels 16A, 16B and rear wheels 17A, 17B. The front wheels 16A, 16B are rotatably supported by the front vehicle body 3. The rear wheels 17A, 17B are rotatably supported by the rear vehicle body 4.

[0012] The work implement 5 is movably connected to the vehicle body 2. The work implement 5 is used for work such as excavation. The work implement 5 is attached to the front vehicle body 3. The work implement 5 includes a boom 11, a bucket 12, a boom cylinder 13, and a bucket cylinder 14. The boom cylinder 13 and the bucket cylinder 14 are hydraulic cylinders. The boom 11 moves when the boom cylinder 13 extends and retracts. The bucket 12 moves when the bucket cylinder 14 extends and retracts.

[0013] As shown in Fig. 2, the drive system 10 includes a battery 21, a power control circuit 22, a first electric motor 23, and a second electric motor 24. The first electric motor 23 includes a first output shaft 231. The second electric motor 24 includes a second output shaft 241. The battery 21 supplies power to the first electric motor 23 and the second electric motor 24. As shown in Fig. 1, the battery 21 is disposed in the power compartment 9.

[0014] The power control circuit 22 controls the power supplied to the first electric motor 23 and the second electric motor 24. The power control circuit 22 includes, for example, an inverter. The first electric motor 23 generates a driving force for driving the traveling device 6. The second electric motor 24 generates a driving force for driving the work implement 5.

[0015] The drive system 10 includes a hydraulic pump 25 and a control valve 26. The hydraulic pump 25 is a variable displacement hydraulic pump. The hydraulic pump 25 is connected to the second output shaft 241 of the second electric motor 24. The hydraulic pump 25 is driven by the second electric motor 24 to supply hydraulic oil to the above-mentioned hydraulic cylinders 13-15. The control valve 26 is connected to the hydraulic pump 25 and the hydraulic cylinders 13-15 via a hydraulic circuit. The control valve 26 includes a plurality of valves. The control valve 26 controls the flow rate of hydraulic oil supplied from the hydraulic pump 25 to the hydraulic cylinders 13-15.

[0016] The traveling device 6 described above includes a drive shaft 27, a front axle 28, and a rear axle 29. The drive shaft 27 is connected to the front axle 28 and the rear axle 29. The front wheels 16A, 16B are connected to the drive shaft 27 via the front axle 28. The rear wheels 17A, 17B are connected to the drive shaft 27 via the rear axle 29.

[0017] The drive system 10 includes a transmission 31. The transmission 31 includes an input shaft 32, a speed change gear set 33, and an output shaft 34. The input shaft 32 of the transmission 31 is connected to a first output shaft 231 of the first electric motor 23. The speed change gear set 33 includes a plurality of speed change gears, and is connected to the input shaft 32 and the output shaft 34. The output shaft 34 of the transmission 31 is connected to a drive shaft 27 of the traveling device 6. The transmission 31 changes the speed of the driving force from the first electric motor 23 and transmits it to the traveling device 6.

[0018] In the work machine 1 according to this embodiment, the above-described transmission 31, first electric motor 23, second electric motor 24, and hydraulic pump 25 are integrated together as an electric powertrain unit 30. As shown in Fig. 1 , the electric powertrain unit 30 is mounted on the vehicle body 2. The electric powertrain unit 30 is disposed below the operator's cab 7.

[0019] Fig. 3 is a perspective view of the electric powertrain unit 30. Fig. 4 is a side view of the electric powertrain unit 30. Fig. 5 is a top view of the electric powertrain unit 30. Fig. 6 is an exploded perspective view of the electric powertrain unit 30. As shown in Figs. 3 to 6, the transmission 31 includes a transmission housing 35. The transmission housing 35 houses the input shaft 32, the output shaft 34, and the transmission gear set 33 described above.

[0020] The transmission housing 35 includes an upper housing portion 36 and a lower housing portion 37. As shown in FIG. 3 , the input shaft 32 is disposed within the upper housing portion 36. The output shaft 34 is disposed within the lower housing portion 37. The upper housing portion 36 is smaller than the lower housing portion 37 in the vehicle front-rear direction. A front surface 361 of the upper housing portion 36 is located rearward of a front surface 371 of the lower housing portion 37. The lower housing portion 37 includes an upper surface 372. The upper surface 372 of the lower housing portion 37 extends forward from the front surface 361 of the upper housing portion 36.

[0021] The first electric motor 23 includes a first motor housing 232. The first motor housing 232 accommodates a first output shaft 231. The first electric motor 23 is attached to the transmission housing 35. The first electric motor 23 is attached to a front surface 361 of the upper housing portion 36. The first motor housing 232 includes a first motor fixing portion 233. The first motor housing 232 is fixed to the transmission housing 35 at the first motor fixing portion 233. The first motor fixing portion 233 has a flange-like shape. The first motor fixing portion 233 is fixed to the transmission housing 35 by a fixing member such as a bolt.

[0022] The electric powertrain unit 30 includes a motor bracket 40. The motor bracket 40 is separate from the transmission 31 and the second electric motor 24. The motor bracket 40 is attached to a transmission housing 35. The motor bracket 40 is detachably attached to the transmission housing 35 by a fastening member such as a bolt. The second electric motor 24 is attached to the motor bracket 40. The second electric motor 24 is supported by the transmission housing 35 via the motor bracket 40.

[0023] 7 and 8 are perspective views of the transmission 31 and the motor bracket 40. Fig. 9 is a rear view of the transmission 31 and the motor bracket 40. As shown in Figs. 7 to 9, the motor bracket 40 includes a bracket main body 41, a first bracket fixing portion 42, and a second bracket fixing portion 43.

[0024] The bracket body 41 is a portion to which the second electric motor 24 is attached. The bracket body 41 has a plate-like shape. The bracket body 41 has a generally circular shape. As shown in FIG. 9 , an upper end 411 of the bracket body 41 is located above an upper end 351 of the transmission housing 35. A lower end 412 of the bracket body 41 is located below an upper end 351 of the transmission housing 35. The bracket body 41 includes an opening 44. The opening 44 penetrates the bracket body 41 in the front-to-rear direction of the vehicle.

[0025] The first bracket fixing portion 42 and the second bracket fixing portion 43 are connected to the bracket main body 41. The first bracket fixing portion 42 extends laterally from the bracket main body 41. The second bracket fixing portion 43 extends downward from the bracket main body 41. The motor bracket 40 is fixed to the transmission housing 35 at the first bracket fixing portion 42 and the second bracket fixing portion 43.

[0026] The transmission housing 35 includes a first transmission fixing portion 38 and a second transmission fixing portion 39. The first transmission fixing portion 38 is connected to the upper housing portion 36. As shown in FIGS. 7 and 9 , the first transmission fixing portion 38 is disposed on an upper surface 362 of the upper housing portion 36. The first bracket fixing portion 42 is fixed to the first transmission fixing portion 38. The second transmission fixing portion 39 is connected to the lower housing portion 37. The second transmission fixing portion 39 is disposed on an upper surface 372 of the lower housing portion 37. The second bracket fixing portion 43 is fixed to the second transmission fixing portion 39.

[0027] The second electric motor 24 includes a second motor housing 242. The second motor housing 242 houses a second output shaft 241. The second electric motor 24 is detachably attached to the bracket body 41. The second electric motor 24 is attached to the bracket body 41 from the front of the bracket body 41. The second motor housing 242 includes a second motor fixing portion 243. The second motor fixing portion 243 has a flange-like shape. The second motor housing 242 is fixed to the transmission housing 35 at the second motor fixing portion 243. The second motor fixing portion 243 is fixed to the transmission housing 35 by a fixing member such as a bolt.

[0028] As shown in Figures 4 and 5, in the electric powertrain unit 30, the first electric motor 23 is attached to the transmission housing 35 so that the first output shaft 231 and the second output shaft 241 are arranged in parallel to each other, and the second electric motor 24 is attached to the transmission housing 35 via the motor bracket 40.

[0029] Furthermore, the hydraulic pump 25 is attached to the second electric motor 24. The hydraulic pump 25 is not attached to the motor bracket 40, but is supported by the motor bracket 40 via the second electric motor 24. However, the hydraulic pump 25 may be attached to the motor bracket 40.

[0030] The hydraulic pump 25 is disposed coaxially with the second electric motor 24. The motor bracket 40 is disposed between the hydraulic pump 25 and the second electric motor 24. The hydraulic pump 25 and the second electric motor 24 are disposed through an opening 44. The hydraulic pump 25 is disposed rearward of the motor bracket 40. The second electric motor 24 is disposed forward of the motor bracket 40.

[0031] The second electric motor 24 is disposed on the same side of the transmission 31 as the first electric motor 23 in the vehicle longitudinal direction. The hydraulic pump 25 is disposed on the opposite side of the transmission 31 from the first electric motor 23 and the second electric motor 24 in the vehicle longitudinal direction. In other words, the first electric motor 23 and the second electric motor 24 are disposed in front of the transmission 31. The hydraulic pump 25 is disposed behind the transmission 31.

[0032] The first electric motor 23 and the second electric motor 24 are disposed close to each other. As shown in FIG. 4 , the first electric motor 23 and the second electric motor 24 are disposed vertically side by side in a side view of the vehicle. In a side view of the vehicle, an upper surface 244 of the second electric motor 24 is located higher than an upper surface 234 of the first electric motor 23. In a side view of the vehicle, the first electric motor 23 and the second electric motor 24 at least partially overlap each other. As shown in FIG. 5 , in a top view of the vehicle, the first electric motor 23 and the second electric motor 24 are disposed horizontally side by side. In a top view of the vehicle, the first electric motor 23 and the second electric motor 24 at least partially overlap each other.

[0033] 3 , the electric powertrain unit 30 is attached to the vehicle body 2 via mount brackets 51 and 52. The mount brackets 51 and 52 are attached to the transmission housing 35. The mount brackets 51 and 52 include mount members 53 and 54 made of an elastic material. The electric powertrain unit 30 is supported on the vehicle body 2 via the mount members 53 and 54.

[0034] Fig. 10 is a side view showing the electric powertrain unit 30 mounted on the vehicle body 2. Fig. 11 is a top view showing the electric powertrain unit 30 mounted on the vehicle body 2. Fig. 12 is a front view showing the electric powertrain unit 30 mounted on the vehicle body 2. As shown in Figs. 10 to 12 , the vehicle body 2 includes a body frame 60. The electric powertrain unit 30 is supported by the body frame 60. Note that a portion of the body frame 60 is omitted in Figs. 10 to 12 for ease of understanding.

[0035] As shown in Figures 10 to 12, the body frame 60 includes a first side frame 61, a second side frame 62, and a cross frame 63. The first side frame 61 and the second side frame 62 extend in the front-rear direction of the vehicle. The first side frame 61 and the second side frame 62 are spaced apart in the left-right direction of the vehicle. The cross frame 63 extends in the left-right direction of the vehicle. The cross frame 63 is connected to the first side frame 61 and the second side frame 62.

[0036] The electric powertrain unit 30 is disposed between the first side frame 61 and the second side frame 62. As shown in Figure 11, in a top view of the vehicle, at least a portion of the first electric motor 23 is disposed on one side of the center line C1 of the vehicle body 2 extending in the front-to-rear direction of the work machine 1. In a top view of the vehicle, at least a portion of the second electric motor 24 is disposed on the other side of the center line C1 of the vehicle body 2 extending in the front-to-rear direction of the work machine 1. In the present embodiment, in a top view of the vehicle, at least a portion of the first electric motor 23 is disposed on the left side of the center line C1 of the vehicle body 2 extending in the front-to-rear direction of the work machine 1. In a top view of the vehicle, at least a portion of the second electric motor 24 is disposed on the right side of the center line C1 of the vehicle body 2 extending in the front-to-rear direction of the work machine 1.

[0037] When viewed from above the vehicle, the central axis A1 of the first electric motor 23 is disposed on one side of the center line C1 of the vehicle body 2 extending in the front-to-rear direction of the work machine 1. When viewed from above the vehicle, the central axis A2 of the second electric motor 24 is disposed on the other side of the center line C1 of the vehicle body 2 extending in the front-to-rear direction of the work machine 1. In the present embodiment, when viewed from above the vehicle, the central axis A1 of the first electric motor 23 is disposed on the left side of the center line C1 of the vehicle body 2 extending in the front-to-rear direction of the work machine 1. When viewed from above the vehicle, the central axis A2 of the second electric motor 24 is disposed on the right side of the center line C1 of the vehicle body 2 extending in the front-to-rear direction of the work machine 1. However, the first electric motor 23 and the second electric motor 24 may be disposed left-to-right.

[0038] 10 , the hydraulic oil tank 8 described above is disposed above the first side frame 61 and the second side frame 62. The hydraulic oil tank 8 is disposed rearward of the transmission 31. The hydraulic pump 25 is disposed below the hydraulic oil tank 8. The hydraulic pump 25 is connected to the hydraulic oil tank 8 via hydraulic piping 64.

[0039] In the work machine 1 according to the present embodiment described above, the first electric motor 23 is attached to the transmission housing 35, and the second electric motor 24 is attached to the transmission housing 35 via the motor bracket 40. As a result, the first electric motor 23, the second electric motor 24, and the transmission 31 are unitized as the electric powertrain unit 30. Therefore, the first electric motor 23 and the second electric motor 24 can be arranged compactly. Furthermore, the structures for attaching the first electric motor 23 and the second electric motor 24 within the vehicle body 2 are either not necessary or can be made smaller. As a result, the vehicle body 2 of the work machine 1 can be made smaller.

[0040] This also improves the ease of assembling the first electric motor 23, the second electric motor 24, and the transmission 31 to the vehicle body 2. For example, by attaching the electric powertrain unit 30 to the vehicle body 2, the first electric motor 23, the second electric motor 24, and the transmission 31 can be attached as a unit to the vehicle body 2. Alternatively, by removing the electric powertrain unit 30 from the vehicle body 2, the first electric motor 23, the second electric motor 24, and the transmission 31 can be removed as a unit from the vehicle body 2.

[0041] Furthermore, by removing the motor bracket 40 from the transmission housing 35, the motor bracket 40, the second electric motor 24, and the hydraulic pump 25 can be removed as a unit from the vehicle body 2. By attaching the motor bracket 40 to the transmission housing 35, the motor bracket 40, the second electric motor 24, and the hydraulic pump 25 can be attached as a unit to the vehicle body 2. This improves maintainability.

[0042] 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 gist of the invention.

[0043] The work machine 1 is not limited to a wheel loader, but may be other machines such as a bulldozer, a motor grader, or a shovel. The configuration of the work machine 1 is not limited to that of the above embodiment and may be modified. For example, the structure of the body frame 60 is not limited to that of the above embodiment and may be modified.

[0044] The location of the hydraulic oil tank 8 is not limited to that in the above embodiment and may be changed. For example, as shown in Fig. 13 , the hydraulic oil tank 8 may be located forward of the transmission 31. In this case, the locations of the second electric motor 24 and the hydraulic pump 25 in the electric powertrain unit 30 may be changed depending on the location of the hydraulic oil tank 8.

[0045] 14 is a perspective view showing an electric powertrain unit 30 according to a modified example. In the electric powertrain unit 30, the hydraulic pump 25 and the second electric motor 24 may be arranged interchangeably with each other on the motor bracket 40. For example, the second electric motor 24 may be attached to the same motor bracket 40 from either the front or the rear. Alternatively, a motor bracket 40 for attaching the second electric motor 24 from the front and a motor bracket 40 for attaching the second electric motor 24 from the rear may be selectively used.

[0046] 13 and 14 , in the electric powertrain unit 30 according to the modified example, the hydraulic pump 25 and the second electric motor 24 are disposed relative to the motor bracket 40 in a manner opposite to the arrangement in the above embodiment. That is, the second electric motor 24 is disposed rearward of the motor bracket 40. The hydraulic pump 25 is disposed in front of the motor bracket 40. As a result, the hydraulic pump 25 is disposed closer to the hydraulic oil tank 8 than when the hydraulic pump 25 is disposed rearward of the motor bracket 40. This makes it easier to route the hydraulic piping 64 from the hydraulic oil tank 8 to the hydraulic pump 25.

[0047] The structure of the electric powertrain unit 30 is not limited to that of the above embodiment and may be modified. For example, the upper end 411 of the bracket body 41 may be located lower than the upper end 351 of the transmission housing 35. The shape of the bracket body 41 is not limited to a circle as in the above embodiment and may be another shape such as a polygon.

[0048] The arrangement of the first electric motor 23 and the second electric motor 24 is not limited to that in the above embodiment and may be changed. For example, the first electric motor 23 and the second electric motor 24 may be arranged so as not to overlap each other when viewed from the side of the vehicle. The first electric motor 23 and the second electric motor 24 may be arranged so as not to overlap each other when viewed from above the vehicle. Another device, such as a speed reducer, may be added between the second electric motor 24 and the hydraulic pump 25.

[0049] According to the present disclosure, the vehicle body can be made smaller in a work machine equipped with multiple electric motors.

[0050] 2: Vehicle body, 5: Work equipment, 6: Traveling device, 23: First electric motor, 24: Second electric motor, 25: Hydraulic pump, 30: Electric power train unit, 31: Transmission, 32: Input shaft, 34: Output shaft, 35: Transmission housing, 40: Motor bracket, 41: Bracket body, 42: First bracket fixing portion, 44: Opening, 53: Mounting member, 231: First output shaft, 241: Second output shaft

Claims

1. A working machine comprising a vehicle body, a traveling device attached to the vehicle body for driving the vehicle body, a working implement movably connected to the vehicle body, and an electric power train unit for driving the traveling device and the working implement, wherein the electric power train unit includes a transmission including an input shaft, an output shaft connected to the traveling device, and a housing for accommodating the input shaft and the output shaft, a first electric motor for the traveling device including a first output shaft connected to the input shaft and attached to the housing, a bracket attached to the housing, and a second electric motor for the working implement attached to the bracket and supported by the housing via the bracket.

2. The working machine according to claim 1, wherein the electric power train unit further includes a hydraulic pump for discharging hydraulic oil for driving the working implement by being driven by the second electric motor, the second electric motor includes a second output shaft, and the hydraulic pump is connected to the second output shaft and arranged coaxially with the second electric motor.

3. The working machine according to claim 2, wherein the bracket is arranged between the hydraulic pump and the second electric motor.

4. The bracket includes a bracket body including an opening, and a fixing portion connected to the bracket body and fixed to the housing, and the hydraulic pump and the second electric motor are arranged through the opening. The working machine according to claim 3.

5. The hydraulic pump and the second electric motor can be arranged by being interchanged with each other with respect to the bracket. The working machine according to claim 3.

6. The second electric motor includes a second output shaft, and the first output shaft and the second output shaft are arranged in parallel with each other. The working machine according to claim 1.

7. In a top view of the vehicle, at least a part of the first electric motor is arranged on one side of the center line of the vehicle body extending in the front-rear direction of the working machine, and in a top view of the vehicle, at least a part of the second electric motor is arranged on the other side of the center line of the vehicle body extending in the front-rear direction of the working machine. The working machine according to claim 1.

8. The working machine according to claim 1, wherein in a top view of the vehicle, the first electric motor and the second electric motor at least partially overlap each other.

9. The working machine according to claim 1, wherein in a side view of the vehicle, the first electric motor and the second electric motor at least partially overlap each other.

10. The working machine according to claim 1, wherein the bracket is detachably attached to the housing.

11. The working machine according to claim 1, wherein the electric power train unit further includes a mounting member made of an elastic body attached to the housing, and the electric power train unit is supported by the vehicle body via the mounting member.

12. An electric power train unit for a working machine, comprising: a transmission including an input shaft, an output shaft, and a housing that houses the input shaft and the output shaft; a first electric motor including a first output shaft connected to the input shaft and attached to the housing; a bracket attached to the housing; a second electric motor including a second output shaft, attached to the bracket, and supported by the housing via the bracket; and a hydraulic pump connected to the second output shaft.

13. The electric power train unit according to claim 12, wherein the hydraulic pump is arranged coaxially with the second electric motor.

14. The electric power train unit according to claim 13, wherein the bracket is arranged between the hydraulic pump and the second electric motor.

15. The electric power train unit according to claim 14, wherein the bracket includes: a bracket body including an opening; and a fixing portion connected to the bracket body and fixed to the housing, and the hydraulic pump and the second electric motor are arranged through the opening.

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