Work vehicle

Abstract

To suppress an increase in the weight of a hybrid type working vehicle equipped with a motor, a generator, a first planetary device and a second planetary device when the output of the motor and the generator is increased.SOLUTION: In a plan view, a motor transmission shaft 21a of the motor 21 and a first input shaft 41 of the first planetary device 23 are provided on one of left and right sides with respect to the engine transmission shaft 18, and a generator transmission shaft 22a of the generator 22 and a second input shaft 42 of the second planetary device 24 are provided on the other of the left and right sides. The first input shaft 41 is provided at a position closer to the engine transmission shaft 18 than the motor transmission shaft 21a. The second input shaft 42 is provided at a position closer to the engine transmission shaft 18 than the generator transmission shaft 22a.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to the configuration of a travel transmission system in a work vehicle. [Background technology]

[0002] As disclosed in Patent Document 1, a tractor is an example of a work vehicle, and in addition to the engine, a motor and a generator are provided, and the power of the engine and the power of the motor are transmitted to a planetary gear and combined, and the combined power is transmitted from the planetary gear to the traveling gear, making it a hybrid tractor.

[0003] It has been proposed to provide two planetary gear units for work vehicles to increase the speed range. In this case, a configuration is considered in which the motor and generator are arranged side by side in the left-right direction, and the first planetary gear unit and the second planetary gear unit are arranged side by side in the left-right direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-177846 Summary of the Invention [Problem to be solved by the invention]

[0005] Unlike ordinary passenger vehicles, low-speed, high-torque power is transmitted to the travel gear of a work vehicle. Therefore, in a hybrid work vehicle equipped with a motor and generator, if the motor and generator are to be made more powerful, the cores of the motor and generator must be enlarged.

[0006] As described above, when the cores of the motor and generator are increased in size, the case that houses the first planetary device and the second planetary device also becomes larger, which leads to an increase in the weight of the work vehicle. For this reason, there is a demand for a configuration that can suppress the increase in weight of the work vehicle even if the cores of the motor and generator are increased in size.

[0007] The present invention aims to reduce the increase in weight of a hybrid work vehicle equipped with a motor, a generator, a first planetary device, and a second planetary device when the motor and generator are increased in output. [Means for solving the problem]

[0008] The work vehicle of the present invention comprises a traveling device, an engine, a battery, an engine transmission shaft provided along the longitudinal direction and to which power from the engine is transmitted, a traveling transmission shaft provided along the longitudinal direction, a motor transmission shaft provided along the longitudinal direction, a motor that transmits power from the motor transmission shaft to the traveling transmission shaft, a generator transmission shaft provided along the longitudinal direction, a generator to which power from the engine transmission shaft is transmitted from the generator transmission shaft, and a first input shaft provided along the longitudinal direction, and the power of the engine transmission shaft and the power of the traveling transmission shaft are transmitted, and the transmitted power is combined to operate the traveling the first planetary device having a first input shaft extending in the front-to-rear direction, through which the power of the engine transmission shaft and the power of the traveling transmission shaft are transmitted and which is capable of combining the transmitted power and transmitting it to the traveling device; and a second planetary device having a second input shaft extending in the front-to-rear direction, through which the power of the engine transmission shaft and the power of the traveling transmission shaft are transmitted and which is capable of combining the transmitted power and transmitting it to the traveling device; in a plan view, the motor transmission shaft and the first input shaft are provided on one right or left side of the engine transmission shaft, and the generator transmission shaft and the second input shaft are provided on the other right or left side, the first input shaft is provided at a position closer to the engine transmission shaft than the motor transmission shaft, and the second input shaft is provided at a position closer to the engine transmission shaft than the generator transmission shaft.

[0009] According to the present invention, the motor and generator are arranged side by side in the left-right direction, and the first planetary device and the second planetary device are arranged side by side in the left-right direction. In this state, if the cores of the motor and generator are enlarged, the motor and generator will be separated to the right and left from the engine transmission shaft.

[0010] According to the present invention, even if the motor and generator are moved to the right and left away from the engine transmission shaft, the first input shaft of the first planetary device is located at a position closer to the engine transmission shaft than the motor transmission shaft of the motor, and the second input shaft of the second planetary device is located at a position closer to the engine transmission shaft than the generator transmission shaft of the generator.

[0011] As a result, even if the cores of the motor and generator are enlarged and the motor and generator move away to the right and left from the engine transmission shaft, the positions of the first planetary device and the second planetary device do not change relative to the engine transmission shaft, or the first planetary device and the second planetary device do not move away very far to the right and left from the engine transmission shaft, and the case that houses the first planetary device and the second planetary device is unlikely to become large. When the motor and generator are increased in output, the case that houses the first planetary device and the second planetary device does not need to be increased in size, which reduces the weight of the work vehicle. By reducing the weight of the work vehicle, the driving performance of the work vehicle can be improved.

[0012] In the present invention, it is preferable that, in a plan view, the left-right distance between the engine transmission shaft and the first input shaft is set to a value larger than the left-right distance between the motor transmission shaft and the first input shaft, and that, in a plan view, the left-right distance between the engine transmission shaft and the second input shaft is set to a value larger than the left-right distance between the generator transmission shaft and the second input shaft.

[0013] The first planetary mechanism has a predetermined outer diameter centered on the first input shaft, and the second planetary device has a predetermined outer diameter centered on the second input shaft. According to the present invention, the first planetary device and the second planetary device are arranged so as not to be too close to the engine transmission shaft, thereby avoiding interference between the first planetary device and the engine transmission shaft, while allowing the first input shaft of the first planetary device to be comfortably arranged at a position closer to the engine transmission shaft than the motor transmission shaft of the motor, and the second input shaft of the second planetary device to be comfortably arranged at a position closer to the engine transmission shaft than the generator transmission shaft of the generator.

[0014] In the present invention, the motor and the generator are preferably motor generators.

[0015] According to the present invention, since the motor and the generator are a motor-generator, the motor can be operated as a generator and the generator can be operated as a motor.

[0016] This allows the motor to operate as a generator, thereby enabling the motor (generator) to generate power and the generator to charge the battery. By operating the generator as a motor, the power of the engine, the power of the motor, and the power of the generator (motor) can be combined by the first planetary device (second planetary device) and transmitted to the traveling device. By operating the generator as a motor, the power of the motor and the power of the generator (motor) can be combined by the first planetary device (second planetary device) and transmitted to the traveling device, without transmitting the power of the engine to the first planetary device (second planetary device).

[0017] As described above, by using a motor-generator as the motor and generator, it is possible to respond to various driving conditions, which is advantageous in terms of improving the driving performance of the work vehicle.

[0018] In the present invention, it is preferable that a motor gear mechanism be provided that reduces the power of the motor transmission shaft and transmits it to the traveling transmission shaft, and a generator gear mechanism be provided that increases the power of the engine transmission shaft and transmits it to the generator transmission shaft.

[0019] According to the present invention, the power of the motor is reduced by the motor gear mechanism and transmitted to the first planetary device (second planetary device). By driving the motor to rotate at high speed, the high-speed, low-torque power of the motor is converted into low-speed, high-torque power and transmitted to the first planetary device (second planetary device), which, combined with an increase in the size of the motor core, enables the motor to have a higher output.

[0020] According to the present invention, the power of the engine is accelerated by the generator gear mechanism and transmitted to the generator, which rotates at high speed. This, combined with the enlargement of the generator core, enables the generator to have a higher output. This, combined with the increased size of the motor and generator, allows for increased output from the motor and generator, which is advantageous in terms of improving the running performance of the work vehicle.

[0021] In the present invention, it is preferable that the travel transmission shaft is formed in a cylindrical shape, and the engine transmission shaft is provided inside the travel transmission shaft.

[0022] According to the present invention, the engine transmission shaft and the traveling transmission shaft are provided in the same position, the space used for arranging the engine transmission shaft and the traveling transmission shaft is kept small, and power is transmitted smoothly from the engine output shaft and the traveling transmission shaft to the first planetary device and the second planetary device.

[0023] This is advantageous in that interference between the first planetary device and the second planetary device and the engine transmission shaft is avoided, while the first input shaft of the first planetary device is positioned closer to the engine transmission shaft than the motor transmission shaft of the motor, and the second input shaft of the second planetary device is positioned closer to the engine transmission shaft than the generator transmission shaft of the generator.

[0024] In the present invention, it is preferable that the first input shaft is provided at a higher position than the motor transmission shaft, the second input shaft is provided at a higher position than the generator transmission shaft, and the engine transmission shaft is provided at a higher position than the first input shaft and the second input shaft.

[0025] According to the present invention, since the engine transmission shaft is located higher than the motor transmission shaft of the motor and the generator transmission shaft of the generator, even if the cores of the motor and generator are increased in size, the motor and generator can be placed closer to each other while avoiding interference with the engine transmission shaft.Similarly, the first planetary device and the second planetary device can be placed closer to each other while avoiding interference with the engine transmission shaft.

[0026] This prevents the case housing the motor and generator from becoming too large, and prevents the case housing the first planetary device and the second planetary device from becoming too large, which is advantageous in terms of preventing an increase in the weight of the work vehicle and improving the driving performance of the work vehicle.

[0027] According to the present invention, the first input shaft of the first planetary mechanism is provided at a position higher than the motor transmission shaft of the motor, and the second input shaft of the second planetary mechanism is provided at a position higher than the generator transmission shaft of the generator, so that the first input shaft and the second input shaft of the first planetary device and the second planetary device are provided at positions close to the engine output shaft, thereby smoothly transmitting power from the engine transmission shaft to the first planetary device and the second planetary device.

[0028] According to the present invention, the motor transmission shaft and generator transmission shaft of the motor and generator, and the first input shaft and second input shaft of the first planetary device and second planetary device are provided at positions lower than the engine output shaft. This allows the motor, generator, first planetary device and second planetary device to be located in low positions, lowering the center of gravity of the work vehicle, which is advantageous in terms of improving the running performance of the work vehicle.

[0029] In the present invention, it is preferable that, when viewed in the front-to-rear direction, the motor transmission shaft and the generator transmission shaft are arranged in symmetrical positions with respect to a virtual vertical line that passes vertically through the engine transmission shaft, and the first input shaft and the second input shaft are arranged in symmetrical positions.

[0030] According to the present invention, the motor transmission shaft of the motor and the generator transmission shaft of the generator are arranged in symmetrical positions, and the first input shaft of the first planetary device and the second input shaft of the second planetary device are arranged in symmetrical positions, thereby achieving a balanced arrangement of the engine transmission shaft, first planetary device, second planetary device, motor, and generator, which is advantageous in terms of improving the driving performance of the work vehicle. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 2 is a left side view of the tractor. [Figure 2] FIG. 2 is a schematic view showing the interior of a clutch housing, a gear case, a motor case, and a transmission case. [Figure 3] FIG. 2 is a front view showing the positional relationship between the motor, the generator, the first planetary device, and the second planetary device. DETAILED DESCRIPTION OF THE INVENTION

[0032] A hybrid tractor, which is an example of a work vehicle, is shown in Figures 1 to 3. In Figures 1 to 3, F indicates the forward direction, B indicates the backward direction, U indicates the upward direction, D indicates the downward direction, R indicates the rightward direction, and L indicates the leftward direction.

[0033] (Overall configuration of the tractor) As shown in Figures 1 and 2, right and left front wheels 1 (corresponding to running devices) are provided at the front of the body 3, and right and left rear wheels 2 (corresponding to running devices) are provided at the rear of the body 3, and the body 3 is supported by the front wheels 1 and the rear wheels 2.

[0034] The machine body 3 has an engine 5, a clutch housing 11 connected to the rear of the engine 5, a motor case 12 connected to the rear of the clutch housing 11, a transmission case 13 connected to the rear of the motor case 12, and a front frame 4 connected to the front of the engine 5. Front wheels 1 are mounted on the front frame 4, and rear wheels 2 are mounted to the rear of the transmission case 13.

[0035] A hood 6 is provided at the front of the aircraft body 3, and an engine 5 is covered by the hood 6. A driver's section 9 is provided at the rear of the aircraft body 3. The driver's section 9 is covered by a cabin 10, and is provided with a driver's seat 7 and a steering wheel 8 for steering the front wheels 1.

[0036] (Outline of the transmission system to front wheel 1 and rear wheel 2) 2, a first motor generator 21 (corresponding to a motor) and a second motor generator 22 (corresponding to a generator) are housed inside the motor case 12. Power from the engine 5 is output mainly by the first motor generator 21, and electricity is generated mainly by the second motor generator 22.

[0037] The first planetary device 23, the second planetary device 24, the first clutch 25, the second clutch 26, the forward / reverse switching device 27, the auxiliary transmission 28, the rear wheel differential device 29, the front wheel transmission 30, etc. are housed inside the transmission case 13.

[0038] The power of the engine 5 and the power of the first motor generator 21 are transmitted to the first planetary device 23 and the second planetary device 24 and are combined at each of the first planetary device 23 and the second planetary device 24. The first planetary device 23 outputs the combined power at low speed, and the second planetary device 24 outputs the combined power at high speed.

[0039] When the first clutch 25 is operated to the transmission state, the low-speed combined power of the first planetary device 23 is transmitted to the forward / reverse switching device 27 via the first clutch 25. When the second clutch 26 is operated to the transmission state, the high-speed combined power of the second planetary device 24 is transmitted to the forward / reverse switching device 27 via the second clutch 26.

[0040] The combined low-speed and high-speed power is operated to move forward or backward by a forward / reverse switching device 27. The power of the forward / reverse switching device 27 is transmitted to an auxiliary transmission 28, and then transmitted from the auxiliary transmission 28 to the rear wheels 2 via a rear wheel differential device 29. The power branched between the auxiliary transmission 28 and the rear wheel differential device 29 is transmitted to a front wheel transmission 30, and then transmitted from the front wheel transmission 30 to the front wheels 1 via the front wheel differential device 20.

[0041] (Internal configuration of clutch housing 11) As shown in Figure 2, the rear of clutch housing 11 is connected to the front of motor case 12. A wall 14 separates the interior of clutch housing 11 from the interior of motor case 12. The open portion at the front of clutch housing 11 is closed by being connected to engine 5. A wall 15 is connected to the rear of motor case 12, and wall 15 separates the interior of motor case 12 from the interior of transmission case 13.

[0042] A dry clutch 16 and a gear case 17 are housed inside the clutch housing 11, and the clutch 16 is connected to the output shaft 5a of the engine 5. A transmission shaft 18 (corresponding to the engine transmission shaft) is connected to the clutch 16 and provided along the front-to-rear direction, and extends from inside the clutch housing 11, through inside the gear case 17 and inside the motor case 12, and into the inside of the transmission case 13. Power from the engine 5 is transmitted via the clutch 16 and the transmission shaft 18 to a first planetary device 23 and a second planetary device 24, as described below.

[0043] A gear case 17 is attached to a portion of the wall portion 14 opposite the interior of the motor case 12. The interior of the gear case 17 is separated from the area inside the clutch housing 11 where the clutch 16 is located, and is separated from the interior of the motor case 12 by the wall portion 14.

[0044] (Configuration of the first motor generator 21 and the second motor generator 22) 2 and 3, a cylindrical transmission shaft 19 (corresponding to a traveling transmission shaft) is provided along the front-to-rear direction, passes through the interior of the gear case 17 and the interior of the motor case 12, and extends into the interior of the transmission case 13. The transmission shaft 18 is provided inside the transmission shaft 19, and the transmission shafts 18 and 19 are provided so as to be rotatable independently of each other.

[0045] The first motor generator 21 and the second motor generator 22 are arranged side by side in the left-right direction and are provided on the right and left sides inside the motor case 12. A transmission shaft 21a (corresponding to a motor transmission shaft) of the first motor generator 21 is provided along the front-rear direction, extends forward and enters the interior of the gear case 17. A transmission shaft 22a (corresponding to a generator transmission shaft) of the second motor generator 22 is provided along the front-rear direction, extends forward and enters the interior of the gear case 17.

[0046] (Motor gear mechanism configuration) 2, inside the gear case 17, a transmission gear 31 (corresponding to a motor gear mechanism) is connected to the transmission shaft 19. A transmission gear 21b (corresponding to a motor gear mechanism) is connected to the transmission shaft 21a of the first motor generator 21. The transmission gear 31 and the transmission gear 21b of the first motor generator 21 are in mesh with each other, and the transmission gear 31 is configured to have a larger diameter than the transmission gear 21b of the first motor generator 21.

[0047] The power of the first motor generator 21 (transmission shaft 21a) is reduced in speed via the transmission gear 21b and transmission gear 31 of the first motor generator 21, transmitted to the transmission shaft 19, and then transmitted to the first planetary device 23 and the second planetary device 24 as described below.

[0048] (Configuration of generator gear mechanism) 2, inside the gear case 17, a transmission gear 32 (corresponding to the generator gear mechanism) is connected to the transmission shaft 18. A transmission gear 22b (corresponding to the generator gear mechanism) is connected to the transmission shaft 22a of the second motor generator 22. The transmission gear 32 and the transmission gear 22b of the second motor generator 22 are in mesh, and the transmission gear 32 is configured to have a larger diameter than the transmission gear 22b of the second motor generator 22.

[0049] The power of the engine 5 is accelerated from the transmission shaft 18 via the transmission gear 32 and the transmission gear 22b of the second motor generator 22 and transmitted to the second motor generator 22 (transmission shaft 22a), causing the second motor generator 22 to generate electricity.

[0050] (Configuration related to the first motor generator 21 and the second motor generator 22) As shown in FIG. 2, a first inverter 36 is provided for the first motor generator 21, a second inverter 37 is provided for the second motor generator 22, and a battery 33 is provided.

[0051] When the first motor generator 21 (second motor generator 22) operates as a motor and supplies power to the transmission shaft 18 (transmission shaft 19), the DC power of the battery 73 is converted into AC power by the first inverter 36 (second inverter 37) and supplied to the first motor generator 21 (second motor generator 22), causing the first motor generator 21 (second motor generator 22) to operate as a motor (drive mode).

[0052] When the first motor generator 21 (second motor generator 22) is driven to operate as a generator, AC power generated by the first motor generator 21 (second motor generator 22) is converted into DC power by the first inverter 36 (second inverter 37) and charged into the battery 33 (regeneration mode). Note that a capacitor (not shown) may be used as the battery 33.

[0053] A control device (not shown) sets the regeneration mode and drive mode of the first motor generator 21 and the regeneration mode and drive mode of the second motor generator 22 based on the state of the working device (not shown) attached to the machine body 3, the running state of the machine body 3, etc.

[0054] The basic running state is when the first motor generator 21 is set to the drive mode and the second motor generator 22 is set to the regeneration mode. In a basic running state, the power of the engine 5 is transmitted to the first planetary device 23 and the second planetary device 24, as described below, and the power of the first motor generator 21 is transmitted to the first planetary device 23 and the second planetary device 24.

[0055] By operating the clutch 16 to the disengaged state, it is also possible to stop the engine 5 and run the vehicle in the drive mode of the first motor generator 21 and the drive mode of the second motor generator 22.

[0056] (Configuration of the oil pump 34 that cools the first motor generator 21 and the second motor generator 22) 2, lubricating oil with relatively low viscosity is stored inside motor case 12. An oil pump 34 is provided at the bottom inside gear case 17 so as to be located below transmission shafts 18, 19. A drive shaft 34a of oil pump 34 is provided along the front-rear direction, and a transmission gear 34b is connected to drive shaft 34a of oil pump 34.

[0057] The oil pump 34 is provided at a position lower than the transmission shaft 21a of the first motor generator 21 and the transmission shaft 22a of the second motor generator 22. The oil pump 34 is provided between the transmission shaft 21a of the first motor generator 21 and the transmission shaft 22a of the second motor generator 22 in a plan view.

[0058] A transmission gear 35 is connected to the transmission shaft 18, and the transmission gear 35 is in mesh with a transmission gear 34b of the oil pump 34. The power of the engine 5 is transmitted to the oil pump 34 via the transmission shaft 18 and the transmission gear 35, thereby driving the oil pump 34.

[0059] When the oil pump 34 is driven, the lubricating oil in the motor case 12 is supplied to the oil pump 34 through a filter (not shown), and then from the oil pump 34 through an oil cooler (not shown) to the inside of the first motor generator 21 and the inside of the second motor generator 22. The supplied lubricating oil cools the first motor generator 21 and the second motor generator 22, and returns to the motor case 12 from the first motor generator 21 and the second motor generator 22.

[0060] (Configuration of the first planetary device 23) As shown in FIGS. 2 and 3, the first planetary device 23 and the second planetary device 24 are arranged side by side in the left-right direction and are provided on the right and left sides of the front part inside the transmission case 13.

[0061] The first planetary device 23 has an input shaft 41 (corresponding to the first input shaft), a sun gear 23a, a plurality of planetary gears 23b, a carrier 23c, a ring gear 23d, transmission gears 23e and 23f, and the like.

[0062] An input shaft 41 is provided along the front-rear direction and extends forward. The sun gear 23a and the transmission gear 23f are connected to the input shaft 41. The planetary gear 23b is rotatably supported by the carrier 23c, and the sun gear 23a and the planetary gear 23b mesh with each other, and the ring gear 23d and the planetary gear 23b mesh with each other.

[0063] A transmission gear 23e is connected to the ring gear 23d. A transmission gear 38 is connected to the transmission shaft 18, and the transmission gear 23e of the first planetary device 23 and the transmission gear 38 are in mesh. A transmission gear 39 is connected to the transmission shaft 19, and the transmission gear 23f of the first planetary device 23 and the transmission gear 39 are in mesh.

[0064] The power of the engine 5 (or the power of the second motor generator 22) is transmitted to the ring gear 23d of the first planetary device 23 via the transmission shaft 18 and the transmission gear 38. The power of the first motor generator 21 is transmitted to the input shaft 41 (sun gear 23a) of the first planetary device 23 via the transmission gear 31, the transmission shaft 19, and the transmission gear 39.

[0065] In the first planetary device 23, the power of the engine 5 (or the power of the second motor generator 22) and the power of the first motor generator 21 are combined and changed in speed, and the combined power at low speed is output from the carrier 23c of the first planetary device 23 to the first clutch 25.

[0066] (Configuration of the second planetary device 24) As shown in FIGS. 2 and 3, the second planetary device 24 includes an input shaft 42 (corresponding to the second input shaft), a sun gear 24a, a plurality of planetary gears 24b and a carrier 24c, a ring gear 24d, and transmission gears 24e and 24f.

[0067] An input shaft 42 is provided along the front-rear direction and extends forward. The sun gear 24a and the transmission gear 24f are connected to the input shaft 42. The transmission gear 24e is connected to the carrier 24c. The planetary gear 24b is rotatably supported by the carrier 24c, and the sun gear 24a and the planetary gear 24b mesh with each other, and the ring gear 24d and the planetary gear 24b mesh with each other. The transmission gear 24e of the second planetary device 24 meshes with the transmission gear 38, and the transmission gear 24f of the second planetary device 24 meshes with the transmission gear 39.

[0068] The power of the engine 5 (or the power of the second motor generator 22) is transmitted to the carrier 24c of the second planetary device 24 via the transmission shaft 18 and the transmission gear 38. The power of the first motor generator 21 is transmitted to the input shaft 42 (sun gear 24a) of the second planetary device 24 via the transmission gear 31, the transmission shaft 19, and the transmission gear 39.

[0069] In the second planetary device 24, the power of the engine 5 (or the power of the second motor generator 22) and the power of the first motor generator 21 are combined and changed in speed, and the combined power is output as high-speed combined power from the ring gear 24d of the second planetary device 24 to the second clutch 26.

[0070] (Configuration of the transmission system to the PTO shaft 44) As shown in Fig. 2, inside the transmission case 13, a transmission shaft 45 is connected to the transmission shaft 18, and a PTO clutch 46 is connected to the transmission shaft 45. A PTO speed change device 47 is provided, and a PTO shaft 44 is provided at the rear of the transmission case 13 (see Fig. 1).

[0071] The power of the engine 5 is transmitted to the PTO transmission 47 via the clutch 16, the transmission shafts 18 and 45, and the PTO clutch 46, and then transmitted from the PTO transmission 47 to the PTO shaft 44. When a working device (not shown) is coupled to the rear of the machine body 3, a transmission shaft (not shown) is connected between the PTO shaft 44 and the working device, and the power of the PTO shaft 44 is transmitted to the working device.

[0072] (Configuration of forward / reverse switching device 27) As shown in FIG. 2, the forward / reverse switching device 27 includes a cylindrical shaft 50, a forward clutch 51, a reverse clutch 52, a transmission shaft 53, an intermediate gear 54, and the like.

[0073] A cylindrical shaft 50 is rotatably attached to the transmission shaft 45, and a transmission gear 55 is connected to the cylindrical shaft 50. The transmission gear 55 meshes with the transmission gear 25a of the first clutch 25, and the transmission gear 55 meshes with the transmission gear 26a of the second clutch 26.

[0074] A forward clutch 51 and a reverse clutch 52 are attached to a cylindrical shaft 50. Transmission gears 53a and 53b are connected to a transmission shaft 53, and the output gear of the forward clutch 51 meshes with the transmission gear 53a of the transmission shaft 53. The output gear of the reverse clutch 52 meshes with an intermediate gear 54, and the intermediate gear 54 meshes with the transmission gear 53b of the transmission shaft 53.

[0075] When the first clutch 25 is operated to the transmission state, the low-speed combined power of the first planetary device 23 is transmitted to the cylindrical shaft 50 via the first clutch 25. When the second clutch 26 is operated to the transmission state, the high-speed combined power of the second planetary device 24 is transmitted to the cylindrical shaft 50 via the second clutch 26.

[0076] When the forward clutch 51 is operated to the transmission state, the power of the cylindrical shaft 50 is transmitted to the transmission shaft 53 in a forward state via the forward clutch 51. When the reverse clutch 52 is operated to the transmission state, the power of the cylindrical shaft 50 is transmitted to the transmission shaft 53 in a reverse state via the reverse clutch 52 and the relay gear 54.

[0077] (Configuration of the auxiliary transmission 28) As shown in FIG. 2, the auxiliary transmission 28 includes a high-speed gear 56, a low-speed gear 57, a transmission shaft 58, a rear wheel output shaft 59, a shift member 60, and the like.

[0078] A high-speed gear 56 is connected to the transmission shaft 53, and a transmission gear 58a of the transmission shaft 58 meshes with the high-speed gear 56. A rear-wheel output shaft 59 is provided concentrically with the transmission shaft 53, and a shift member 60 is slidably attached to the rear-wheel output shaft 59. A low-speed gear 57 is rotatably attached to the rear-wheel output shaft 59, and a transmission gear 58b of the transmission shaft 58 meshes with the low-speed gear 57.

[0079] When the shift member 60 is engaged with the high-speed gear 56, the transmission shaft 53 and the rear wheel output shaft 59 are connected, and the power of the transmission shaft 53 is transmitted to the rear wheel output shaft 59 at high speed, and then from the rear wheel output shaft 59 to the rear wheels 2 via the rear wheel differential device 29.

[0080] When the shift member 60 is engaged with the low-speed gear 57, the power of the transmission shaft 53 is transmitted at low speed to the rear wheel output shaft 59 via the high-speed gear 56, the transmission shaft 58 and the low-speed gear 57, and then transmitted from the rear wheel output shaft 59 to the rear wheels 2 via the rear wheel differential device 29.

[0081] (Configuration of front wheel transmission 30) As shown in FIG. 2, the front wheel transmission 30 includes a standard clutch 61, a speed-increasing clutch 62, a transmission shaft 63, a front wheel output shaft 64, and the like.

[0082] A standard clutch 61 and an accelerating clutch 62 are attached to a transmission shaft 63, and power from the rear wheel output shaft 59 is transmitted to the transmission shaft 63. The output gear of the standard clutch 61 meshes with a transmission gear 64a of the front wheel output shaft 64, and the output gear of the accelerating clutch 62 meshes with a transmission gear 64b of the front wheel output shaft 64.

[0083] A cylindrical partition 40 is connected between the wall 14 and the wall 15 inside the motor case 12. A front wheel output shaft 64 passes through the partition 40 from inside the transmission case 13 and protrudes forward, and a transmission shaft 43 is connected between the front wheel differential device 20 and the front wheel output shaft 64.

[0084] Lubricating oil is stored in the transmission case 13, and the lubricating oil can flow between the transmission case 13 and the gear case 17 by passing through the partition 40. The lubricating oil in the motor case 12 is different from the lubricating oil in the transmission case 13 and the gear case 17.

[0085] The interior of the motor case 12 and the interior of the gear case 17 are separated by a wall 14, the interior of the motor case 12 and the interior of the transmission case 13 are separated by a wall 15, and the area inside the partition 40 is separated from the interior of the motor case 12, so that the lubricating oil in the motor case 12 and the lubricating oil in the transmission case 13 and the gear case 17 do not mix with each other.

[0086] When the front wheels 1 are operated within a set angle range to the right or left from the straight ahead position, the standard clutch 61 is operated to the transmission state. The power of the rear wheel output shaft 59 is transmitted to the front wheel output shaft 64 via the transmission shaft 63 and the standard clutch 61, and then to the front wheels 1 via the transmission shaft 43 and the front wheel differential device 20, so that the front wheels 1 and rear wheels 2 are driven at the same speed.

[0087] When the front wheels 1 are steered to the right or left beyond the set right and left angles, the speed increasing clutch 62 is operated into a transmission state. The power of the rear wheel output shaft 59 is transmitted to the front wheel output shaft 64 via the transmission shaft 63 and the speed-increasing clutch 62, and then transmitted to the front wheels 1 via the transmission shaft 43 and the front wheel differential device 20, so that the front wheels 1 are driven at a higher speed than the rear wheels 2.

[0088] (Positional relationship between the first motor generator 21 and the second motor generator 22 and the first planetary device 23 and the second planetary device 24)-1 As shown in FIG. 3, transmission shafts 18 and 19 are provided at upper portions of the left-right central portions of the motor case 12 and the transmission case 13 along the front-rear direction.

[0089] The front wheel output shaft 64 and the partition 40 are provided along the front-rear direction below the central left-right portions of the motor case 12 and the transmission case 13. When viewed from the front-rear direction, if an imaginary vertical line L1 is assumed to pass vertically through the centers of the transmission shafts 18, 19, the centers of the front wheel output shaft 64 and the partition 40 are located on the imaginary vertical line L1.

[0090] The first motor generator 21 and the second motor generator 22 are arranged side by side in the left-right direction inside the motor case 12. The first planetary device 23 and the second planetary device 24 are arranged side by side in the left-right direction at the front inside the transmission case 13.

[0091] In a plan view (front view), the first motor generator 21 (transmission shaft 21a) and the first planetary device 23 (input shaft 41) are provided on the left side of the transmission shafts 18 and 19. The second motor generator 22 (transmission shaft 22a) and the second planetary device 24 (input shaft 42) are provided on the right side of the transmission shafts 18 and 19.

[0092] As a result, in a plan view, the transmission shafts 18, 19, the front wheel output shaft 64 and the partition section 40 are arranged between the first motor generator 21 (transmission shaft 21a) and the second motor generator 22 (transmission shaft 22a), and between the first planetary device 23 (input shaft 41) and the second planetary device 24 (input shaft 42).

[0093] In a side view, the first motor generator 21 (transmission shaft 21a) and the first planetary gear unit 23 (input shaft 41) are provided between the transmission shafts 18, 19 and the front wheel output shaft 64 and the partition unit 40. The second motor generator 22 (transmission shaft 22a) and the second planetary gear unit 24 (input shaft 42) are provided between the transmission shafts 18, 19 and the front wheel output shaft 64 and the partition unit 40.

[0094] The first motor generator 21 (transmission shaft 21a) and the second motor generator 22 (transmission shaft 21a) are provided at a position higher than the front wheel output shaft 64 and the partition portion 40. The first planetary device 23 (input shaft 41) is provided at a position higher than the first motor generator 21 (transmission shaft 21a). The second planetary device 24 (input shaft 42) is provided at a position higher than the second motor generator 22 (transmission shaft 22a). The transmission shafts 18, 19 are provided at a higher position than the first planetary device 23 (input shaft 41) and the second planetary device 24 (input shaft 42).

[0095] (Positional relationship between the first motor generator 21 and the second motor generator 22 and the first planetary device 23 and the second planetary device 24)-2 As shown in FIG. 3, when intervals W21, W22, W23, W24, W25, and W26 are assumed in a plan view (front view), the following state is achieved.

[0096] The distance W21 is the distance between the transmission shafts 18, 19 and the transmission shaft 21a of the first motor generator 21 in the left-right direction. The distance W22 is the distance between the transmission shafts 18, 19 and the transmission shaft 22a of the second motor-generator 22 in the left-right direction.

[0097] The distance W23 is the distance between the transmission shafts 18, 19 and the input shaft 41 of the first planetary device 23 in the left-right direction. The distance W24 is the distance between the transmission shafts 18, 19 and the input shaft 42 of the second planetary device 24 in the left-right direction.

[0098] The distance W25 is the distance between the transmission shaft 21a of the first motor generator 21 and the input shaft 41 of the first planetary device 23 in the left-right direction. The distance W26 is the distance between the transmission shaft 22a of the second motor-generator 22 and the input shaft 42 of the second planetary device 24 in the left-right direction.

[0099] The distance W23 is set to a value smaller than the distance W21. As a result, the input shaft 41 of the first planetary device 23 is located closer to the transmission shafts 18 and 19 than the transmission shaft 21a of the first motor generator 21.

[0100] The distance W24 is set to a value smaller than the distance W22. As a result, the input shaft 42 of the second planetary device 24 is located closer to the transmission shafts 18 and 19 than the transmission shaft 22a of the second motor-generator 22.

[0101] The intervals W21 and W22 are set to the same value, and the intervals W23 and W24 are set to the same value. The interval W23 is set to a value larger than the interval W25. The interval W24 is set to a value larger than the interval W26. The intervals W25 and W26 are set to the same value.

[0102] (Positional relationship between the first motor generator 21 and the second motor generator 22 and the first planetary device 23 and the second planetary device 24)-3 As shown in FIG. 3, when viewed from the front, assuming vertical spacing H21, vertical spacing H22, vertical spacing H23, vertical spacing H24, first virtual line L21, and second virtual line L22, the following state is achieved.

[0103] The vertical distance H21 is the distance between the transmission shafts 18, 19 and the transmission shaft 21a of the first motor generator 21 in the vertical direction. The vertical distance H22 is the distance between the transmission shafts 18, 19 and the transmission shaft 22a of the second motor-generator 22 in the vertical direction.

[0104] The vertical distance H23 is the distance between the transmission shafts 18, 19 and the input shaft 41 of the first planetary device 23 in the vertical direction. The vertical distance H24 is the distance between the transmission shafts 18, 19 and the input shaft 42 of the second planetary device 24 in the vertical direction.

[0105] The first imaginary line L21 is an imaginary straight line that passes through the centers of the transmission shafts 18 and 19 and the center of the transmission shaft 21a of the first motor generator 21. The second imaginary line L22 is an imaginary straight line that passes through the centers of the transmission shafts 18 and 19 and the center of the transmission shaft 22a of the second motor-generator 22.

[0106] The vertical distance H23 is set to a value smaller than the vertical distance H21. The center of the input shaft 41 of the first planetary device 23 is located above (to the left of) the first imaginary line L21. The vertical distance H24 is set to a value smaller than the vertical distance H22. The center of the input shaft 42 of the second planetary device 24 is located above (to the right of) the second imaginary line L22. The vertical spacing H21 and the vertical spacing H22 are set to the same value. The vertical spacing H23 and the vertical spacing H24 are set to the same value.

[0107] (Positional relationship between the first motor generator 21 and the second motor generator 22 and the first planetary device 23 and the second planetary device 24)-4 3, in a front view (front-rear view), the transmission shaft 21a of the first motor-generator 21 and the transmission shaft 22a of the second motor-generator 22 are provided at positions symmetrical with respect to the imaginary vertical line L1. In a front view (front-rear view), the input shaft 41 of the first planetary device 23 and the input shaft 42 of the second planetary device 24 are provided at positions symmetrical with respect to the imaginary vertical line L1.

[0108] The outer diameter R21 of the first motor generator 21 is larger than the outer diameter R23 of the first planetary device 23. The outer diameter R22 of the second motor generator 22 is larger than the outer diameter R24 ​​of the second planetary device 24. The outer diameters R21 and R22 are set to the same value. The outer diameters R23 and R24 are set to the same value.

[0109] The motor case 12 that houses the first motor generator 21 and the second motor generator 22 has a large width W12. In this case, the width W13 of the front part of the transmission case 13 (the part that houses the first planetary device 23 and the second planetary device 24) is smaller than the width W12.

[0110] (Configuration of transmission gear 39 of transmission shaft 19) 2, the motor case 12 and the transmission case 13 are produced in a state where they are separated from each other. The motor case 12 and the transmission case 13 are connected together with the first motor generator 21 and the second motor generator 22 housed in the motor case 12 and the first planetary device 23 and the second planetary device 24 housed in the transmission case 13.

[0111] In this case, the transmission gear 39 is configured to have a relatively large front-to-rear width, and a chamfer 39a is machined on the rear end of the transmission gear 39. The input shaft 42 of the second planetary device 24 is configured to be slightly longer than the input shaft 41 of the first planetary device 23, and the transmission gear 24f of the second planetary device 24 is located slightly forward of the transmission gear 23f of the first planetary device 23.

[0112] When the motor case 12 and the transmission case 13 are connected in the above-described state, as the motor case 12 and the transmission case 13 approach each other, the transmission gear 39 and the transmission gear 24f of the second planetary device 24 come into contact with each other, and the chamfer 39a of the transmission gear 39 smoothly initiates engagement between the transmission gear 39 and the transmission gear 24f of the second planetary device 24.

[0113] As the meshing between the transmission gear 39 and the transmission gear 24f of the second planetary device 24 progresses, the transmission gear 39 then comes into contact with the transmission gear 23f of the first planetary device 23, and the chamfer 39a of the transmission gear 39 smoothly initiates meshing between the transmission gear 39 and the transmission gear 23f of the first planetary device 23.

[0114] As described above, the transmission gear 39 meshes with the transmission gears 23f, 24f of the first planetary device 23 and the second planetary device 24, and the motor case 12 and the transmission case 13 come into contact with each other, thereby connecting the motor case 12 and the transmission case 13.

[0115] (First Alternative Embodiment of the Invention) In plan view (front view), the first motor generator 21 (transmission shaft 21a) and the first planetary device 23 (input shaft 41) may be provided on the right side of the transmission shafts 18, 19, and the second motor generator 22 (transmission shaft 22a) and the second planetary device 24 (input shaft 42) may be provided on the left side of the transmission shafts 18, 19.

[0116] (Second Alternative Embodiment of the Invention) The first planetary device 23 may be configured to output a high-speed combined power, and the second planetary device 24 may be configured to output a low-speed combined power.

[0117] (Third Alternative Embodiment of the Invention) The center of the input shaft 41 of the first planetary device 23 may be located on the first imaginary line L21, and the center of the input shaft 42 of the second planetary device 24 may be located on the second imaginary line L22. In this configuration, too, the transmission shaft 21a of the first motor generator 21 and the transmission shaft 22a of the second motor generator 22 are arranged in symmetrical positions with respect to the virtual vertical line L1, and the input shaft 41 of the first planetary device 23 and the input shaft 42 of the second planetary device 24 are arranged in symmetrical positions.

[0118] (Fourth Alternative Embodiment of the Invention) In the configuration shown in FIG. 3, the transmission shaft 21a of the first motor generator 21 and the transmission shaft 22a of the second motor generator 22 may be disposed in asymmetric positions with respect to the virtual vertical line L1 by the configurations described in the following (4-1) to (4-8).

[0119] (4-1) The vertical distance H21 is set to a value larger than the vertical distance H22. (4-2) The vertical distance H22 is set to a value greater than the vertical distance H21. (4-3) The interval W21 is set to a value greater than the interval W22. (4-4) The interval W22 is set to a value greater than the interval W21.

[0120] (4-5) It has both the configuration of (4-1) and the configuration of (4-3) mentioned above. (4-6) It has both the configuration of (4-1) and the configuration of (4-4) mentioned above. (4-7) It has both the configuration of (4-2) and the configuration of (4-3) mentioned above. (4-8) It has both the configuration of (4-2) and the configuration of (4-4) mentioned above.

[0121] (Fifth Alternative Embodiment of the Invention) In the configuration shown in Figure 3, the input shaft 41 of the first planetary device 23 and the input shaft 42 of the second planetary device 24 may be arranged in asymmetric positions with respect to the virtual vertical line L1 by the configurations described in the following (5-1) to (5-8).

[0122] (5-1) The vertical distance H24 is set to a value greater than the vertical distance H23. In this case, the center of the input shaft 42 of the second planetary device 24 may be located on the second imaginary line L22 or below (to the left of) the second imaginary line L22.

[0123] (5-2) The vertical distance H23 is set to a value greater than the vertical distance H24. In this case, the center of the input shaft 41 of the first planetary device 23 may be located on the first imaginary line L21 or may be located below (to the right of) the first imaginary line L21.

[0124] (5-3) The distance W24 is set to a value smaller than the distance W23. In this case, the center of the input shaft 42 of the second planetary device 24 may be located on the second imaginary line L22 or below (to the left of) the second imaginary line L22.

[0125] (5-4) The distance W23 is set to a value smaller than the distance W24. In this case, the center of the input shaft 41 of the first planetary device 23 may be located on the first imaginary line L21 or may be located below (to the right of) the first imaginary line L21.

[0126] (5-5) It has both the configuration of (5-1) and the configuration of (5-3) described above. (5-6) It has both the configuration of (5-1) and the configuration of (5-4) described above. (5-7) It has both the configuration of (5-2) and the configuration of (5-3) mentioned above. (5-8) It has both the configuration of (5-2) and the configuration of (5-4) described above.

[0127] (Sixth Alternative Embodiment of the Invention) The input shaft 41 of the first planetary device 23 may be provided at a position lower than the transmission shaft 21 a of the first motor generator 21 . The input shaft 42 of the second planetary device 24 may be provided at a position lower than the transmission shaft 22 a of the second motor-generator 22 .

[0128] (Seventh Alternative Embodiment of the Invention) In the configuration described above (sixth variant of the invention), the configuration described above (fourth variant of the invention) or the configuration described above (fifth variant of the invention) may be adopted.

[0129] (Correspondence to claims)-1 The vehicle is equipped with a running device (front wheels 1, rear wheels 2), an engine 5, and a battery 33. The vehicle is provided with an engine transmission shaft (transmission shaft 18) that is provided along the front-rear direction and to which the power of the engine 5 is transmitted, and a traveling transmission shaft (transmission shaft 19) that is provided along the front-rear direction.

[0130] The vehicle is provided with a motor (first motor generator 21) that has a motor transmission shaft (transmission shaft 21a) that is provided along the front-rear direction and transmits power from the motor transmission shaft (transmission shaft 21a) to a traveling transmission shaft (transmission shaft 19). The vehicle is equipped with a generator (second motor generator 22) having a generator transmission shaft (transmission shaft 22a) arranged along the front-to-rear direction, to which the power of the engine transmission shaft (transmission shaft 18) is transmitted from the generator transmission shaft (transmission shaft 22a).

[0131] The vehicle has a first input shaft (input shaft 41) along the longitudinal direction, and is provided with a first planetary device 23 that transmits the power of the engine transmission shaft (transmission shaft 18) and the power of the traveling transmission shaft (transmission shaft 19), and combines the transmitted power and transmits it to the traveling device (front wheels 1, rear wheels 2). The vehicle is provided with a second planetary device 24 that has a second input shaft (input shaft 42) along the longitudinal direction, through which the power of the engine transmission shaft (transmission shaft 18) and the power of the traveling transmission shaft (transmission shaft 18) are transmitted, and that combines the transmitted power and transmits it to the traveling device (front wheels 1, rear wheels 2).

[0132] In a plan view, the motor transmission shaft (transmission shaft 21a) and the first input shaft (input shaft 41) are provided on one side of the engine transmission shaft (transmission shaft 18), and the generator transmission shaft (transmission shaft 22a) and the second input shaft (input shaft 42) are provided on the other side.

[0133] The first input shaft (input shaft 41) is provided at a position closer to the engine transmission shaft (transmission shaft 18) than to the motor transmission shaft (transmission shaft 21a). The second input shaft (input shaft 42) is provided at a position closer to the engine transmission shaft (transmission shaft 18) than to the generator transmission shaft (transmission shaft 22a).

[0134] (Correspondence to claims)-2 In plan view, the left-right distance W23 between the engine transmission shaft (transmission shaft 18) and the first input shaft (input shaft 41) is set to a value larger than the left-right distance W25 between the motor transmission shaft (transmission shaft 21a) and the first input shaft (input shaft 41).

[0135] In plan view, the left-right distance W24 between the engine transmission shaft (transmission shaft 18) and the second input shaft (input shaft 42) is set to a value larger than the left-right distance W26 between the generator transmission shaft (transmission shaft 22a) and the second input shaft (input shaft 42).

[0136] (Correspondence to claims) - 3 The motor (first motor generator 21) and the generator (second motor generator 22) are motor generators. A motor gear mechanism (transmission gears 21b, 31) is provided to reduce the power of the motor transmission shaft (transmission shaft 21a) and transmit it to the traveling transmission shaft (transmission shaft 19). A generator gear mechanism (transmission gears 22b, 32) is provided to increase the speed of the power of the engine transmission shaft (transmission shaft 18) and transmit it to the generator transmission shaft (transmission shaft 22a). The traveling transmission shaft (transmission shaft 19) is formed in a cylindrical shape. The engine transmission shaft (transmission shaft 18) is provided inside the traveling transmission shaft (transmission shaft 19).

[0137] (Correspondence to claims)-4 The first input shaft (input shaft 41) is provided at a higher position than the motor transmission shaft (transmission shaft 21a). The second input shaft (input shaft 42) is provided at a higher position than the generator transmission shaft (transmission shaft 22a). The engine transmission shaft (transmission shaft 18) is provided at a higher position than the first input shaft (input shaft 41) and the second input shaft (input shaft 42).

[0138] (Correspondence to claims) - 5 When viewed from the front-to-rear direction, the motor transmission shaft (transmission shaft 21a) and the generator transmission shaft (transmission shaft 22a) are arranged symmetrically with respect to a virtual vertical line L1 that passes vertically through the engine transmission shaft (transmission shaft 18), and the first input shaft (input shaft 41) and the second input shaft (input shaft 42) are arranged symmetrically with respect to the virtual vertical line L1. [Industrial Applicability]

[0139] The present invention can be applied not only to tractors, but also to work vehicles that carry and transport loads, work vehicles that tow carts, and construction work vehicles such as wheel loaders, and can also be applied to work vehicles equipped with crawler-type running devices instead of the front wheels 1 and rear wheels 2. [Explanation of symbols]

[0140] 1 Front wheel (running gear) 2 Rear wheels (running gear) 5 Engine 18 Transmission shaft (engine transmission shaft) 19 Transmission shaft (traveling transmission shaft) 21 First motor generator (motor) (motor generator) 21a Transmission shaft (motor transmission shaft) 21b Transmission gear (motor gear mechanism) 22 Second motor generator (generator) (motor generator) 22a Transmission shaft (generator transmission shaft) 22b Transmission gear (generator gear mechanism) 23 First Planetary Gear 24 Second Planetary Gear 31 Transmission gear (motor gear mechanism) 32 Transmission gear (generator gear mechanism) 33 Battery 41 Input shaft (first input shaft) 42 Input shaft (second input shaft) L1 Virtual vertical line W23 Spacing W24 spacing W25 spacing W26 spacing

Claims

1. A running device, an engine, a battery, an engine transmission shaft provided along the front-rear direction and through which power of the engine is transmitted; a travel transmission shaft provided along the front-rear direction; a motor having a motor transmission shaft provided along the front-rear direction and transmitting power from the motor transmission shaft to the traveling transmission shaft; a generator having a generator transmission shaft provided along the front-rear direction, and power of the engine transmission shaft is transmitted from the generator transmission shaft; a first planetary device having a first input shaft along a front-rear direction, to which power of the engine transmission shaft and power of the traveling transmission shaft are transmitted, and which is capable of combining the transmitted power and transmitting the combined power to the traveling device; a second planetary device having a second input shaft along the front-rear direction, to which power from the engine transmission shaft and power from the traveling transmission shaft are transmitted, and which combines the transmitted power and transmits it to the traveling device; In a plan view, the motor transmission shaft and the first input shaft are provided on one right or left side of the engine transmission shaft, and the generator transmission shaft and the second input shaft are provided on the other right or left side, the first input shaft is provided at a position closer to the engine transmission shaft than the motor transmission shaft, The second input shaft is provided at a position closer to the engine transmission shaft than to the generator transmission shaft.

2. a distance between the engine transmission shaft and the first input shaft in the left-right direction is set to a value larger than a distance between the motor transmission shaft and the first input shaft in the left-right direction in a plan view, 2. The work vehicle according to claim 1, wherein, in a plan view, the distance in the left-right direction between the engine transmission shaft and the second input shaft is set to a value greater than the distance in the left-right direction between the generator transmission shaft and the second input shaft.

3. 2. The work vehicle according to claim 1, wherein the motor and the generator are a motor generator.

4. a motor gear mechanism that reduces the power of the motor transmission shaft and transmits it to the traveling transmission shaft; 2. The work vehicle according to claim 1, further comprising a generator gear mechanism that increases the speed of the power of the engine transmission shaft and transmits it to the generator transmission shaft.

5. The traveling transmission shaft is formed in a cylindrical shape, 2. The work vehicle according to claim 1, wherein the engine transmission shaft is provided inside the travel transmission shaft.

6. The first input shaft is provided at a position higher than the motor transmission shaft, the second input shaft is provided at a position higher than the generator transmission shaft, 2. The work vehicle according to claim 1, wherein the engine transmission shaft is provided at a higher position than the first input shaft and the second input shaft.

7. 2. The work vehicle according to claim 1, wherein, when viewed in the front-to-rear direction, the motor transmission shaft and the generator transmission shaft are disposed symmetrically with respect to an imaginary vertical line that passes vertically through the engine transmission shaft, and the first input shaft and the second input shaft are disposed symmetrically with respect to an imaginary vertical line that passes vertically through the engine transmission shaft.

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