Work vehicle

Abstract

To miniaturize a case for storing a transmission device or the like in a hybrid type working vehicle provided with a motor, a generator and the transmission device.SOLUTION: A first transmission system 23 and a 24f capable of transmitting the power of a motor 21 and a second transmission system 2733 capable of transmitting the power of the motor 21 to a traveling device are provided. A transmission device 24 is provided to which the power of the engine 5, the power of the first transmission system 23, and the power of the 24f are transmitted, and which combines the transmitted powers and transmits the combined power to the travel device as forward travel power. A switching device 25,26 is provided which can switch between a forward state in which the power of the transmission device 24 is transmitted to the traveling device and the traveling device is driven forward and a backward state in which the power of the second transmission system 27,33 is transmitted to the traveling device and the traveling device is driven backward.SELECTED DRAWING: Figure 2

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 transmission device and combined, and the combined power is transmitted from the transmission device to the traveling device, making it a hybrid tractor.

[0003] In Patent Document 1, a forward / reverse switching device is provided downstream of a transmission device, and the power of the transmission device is operated by the forward / reverse switching device to move the work vehicle forward and backward. [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] In Patent Document 1, the forward / reverse switching device has two clutches, a forward gear that transmits forward power, a reverse gear that transmits reverse power, etc., and since the two clutches, forward gear, and reverse gear, etc. are arranged in a line along the front-to-rear direction, the forward / reverse switching device has a long front-to-rear length. As a result, the case that houses the transmission device and the like tends to be long in the front-to-rear direction, so there is room for improvement in terms of making the case that houses the transmission device and the like smaller.

[0006] The present invention aims to reduce the size of a case that houses a transmission device and the like in a hybrid type work vehicle equipped with a motor, a generator, and a transmission device. [Means for solving the problem]

[0007] The work vehicle of the present invention is equipped with a traveling device, an engine, a battery, a motor capable of operating in forward and reverse directions, and a generator to which the power of the engine is transmitted, a first transmission system capable of transmitting the power of the motor, a second transmission system capable of transmitting the power of the motor to the traveling device, a transmission device to which the power of the engine and the power of the first transmission system are transmitted, which combines the transmitted power and transmits it to the traveling device as forward power, and a switching device that can switch between a forward state in which the power of the transmission system is transmitted to the traveling device and the traveling device is driven forward, and a reverse state in which the power of the second transmission system is transmitted to the traveling device and the traveling device is driven reverse.

[0008] According to the present invention, the power of the motor is transmitted via the first transmission system, and the power of the engine and the power of the first transmission system are transmitted to the transmission device, where the power is combined. The combined power is then transmitted to the traveling device as forward power, causing the work vehicle to move forward.

[0009] According to the present invention, a second transmission system that transmits power from the motor to the traveling device is provided separately from the first transmission system. When power for reverse travel is output from the motor, this power is not transmitted to the transmission system but is transmitted to the traveling device by the second transmission system, bypassing the transmission system, causing the work vehicle to move in reverse. This allows the first transmission system and the transmission device to be arranged in parallel in the left-right or up-down direction, rather than being arranged in series in the front-rear direction, and the second transmission system to be arranged in parallel in the left-right or up-down direction, etc.

[0010] According to the present invention, by arranging the first transmission system and transmission device and the second transmission system in parallel, the front-to-rear length of the space required to arrange the first transmission system and transmission device and the second transmission system is reduced, making it possible to reduce the size of the case that houses the transmission device, etc. By reducing the size of the case that houses the transmission device, etc., it is possible to prevent an increase in the weight of the work vehicle, thereby improving the driving performance of the work vehicle. According to the present invention, the work vehicle is driven in reverse by motor power, but since work vehicles often work while moving forward, the frequency of reversing is low and the distance traveled in reverse is short, so there is little disadvantage to the work vehicle being driven in reverse by motor power.

[0011] In the present invention, it is preferable that the switching device has a first clutch that can be operated to a transmission state in which the power of the transmission device is transmitted to the traveling device and a disconnection state in which the power is disconnected, and a second clutch that can be operated to a transmission state in which the power of the second transmission system is transmitted to the traveling device and a disconnection state in which the power is disconnected.

[0012] According to the present invention, when the first clutch is operated to the transmission state and the second clutch is operated to the disengaged state, the power combined in the transmission device is transmitted to the traveling device via the first clutch, and the power of the motor is not transmitted to the traveling device via the second transmission system, so the work vehicle moves forward. When the first clutch is disengaged and the second clutch is engaged, the combined power of the transmission device is not transmitted to the travel device. When reverse power is output from the motor, the motor power is transmitted to the travel device via the second transmission system and the second clutch, causing the work vehicle to move backward. When the first clutch and the second clutch are disengaged, the combined power of the transmission system and the power of the second transmission system are not transmitted to the traveling device, and the work vehicle comes to a halt.

[0013] As a result, by operating the first clutch and second clutch of the switching device to the transmission state and the disconnected state, the work vehicle can be easily moved forward, backward, and stopped, thereby improving the operability of the work vehicle.

[0014] In the present invention, it is preferable that a motor gear mechanism be provided that reduces the power of the motor and transmits it to the first transmission system and the second transmission system, and a generator gear mechanism be provided that increases the power of the engine and transmits it to the generator.

[0015] According to the present invention, the power of the motor is reduced in speed by the motor gear mechanism, transmitted from the first transmission system to the transmission device, and then transmitted to the traveling device. The power of the motor is reduced in speed by the motor gear mechanism, and transmitted from the second transmission system to the traveling device. As a result, by operating the motor at high speed, the high-speed, low-torque power of the motor is converted into low-speed, high-torque power, making it possible to increase the motor's output without increasing the size of the motor core.

[0016] According to the present invention, the power of the engine is accelerated by the generator gear mechanism and transmitted to the generator, which is then rotated at high speed. This allows the generator to have a high output without having to increase the size of its core. This prevents the case housing the motor and generator from becoming larger and prevents increases in the cost of the motor and generator, while enabling the motor and generator to have higher output, which is advantageous in terms of improving the driving performance of the work vehicle.

[0017] In the present invention, the motor and the generator are preferably motor generators.

[0018] 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.

[0019] This allows the motor to operate as a generator, thereby enabling the battery to be charged by the power generated by the generator and the power generated by the motor (generator). By operating the generator as a motor, the power of the engine, the power of the generator (motor), and the power of the motor can be combined by a transmission device and transmitted to the traveling device. By operating the generator as a motor, the power of the generator (motor) and the power of the motor can be combined by the transmission and transmitted to the running gear without transmitting the power of the engine to the transmission.

[0020] According to the present invention, 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. [Brief explanation of the drawings]

[0021] [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. 4 is a schematic view showing the inside of a clutch housing, a gear case, a motor case, and a transmission case in a first alternative embodiment of the invention. [Figure 4] FIG. 10 is a schematic view showing the inside of a clutch housing, a gear case, a motor case, and a transmission case in a second alternative embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] A hybrid tractor, which is an example of a work vehicle, is shown in Figures 1 to 4. In Figures 1 to 4, F indicates the forward direction, B indicates the rearward direction, U indicates the upward direction, and D indicates the downward direction.

[0023] (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.

[0024] 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.

[0025] 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.

[0026] (Outline of the transmission system to front wheel 1 and rear wheel 2) As shown in Fig. 2, a first motor generator 21 (corresponding to a motor) and a second motor generator 22 (corresponding to a generator) are provided side by side in the left-right direction 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. The first motor generator 21 and the second motor generator 22 are capable of operating in both forward and reverse directions.

[0027] A planetary gear 24 (corresponding to the transmission device), a transmission shaft 27 (corresponding to the second transmission system), a first clutch 25 (corresponding to the switching device), a second clutch 26 (corresponding to the switching device), an auxiliary transmission 28, a rear wheel differential device 29, a front wheel transmission 30, etc. are provided inside the transmission case 13.

[0028] (Internal configuration of clutch housing 11 and motor case 12) As shown in Figure 2, clutch housing 11 and motor case 12 are integrally formed. A wall 14 separates the interior of clutch housing 11 from the interior of motor case 12. An open portion at the front of clutch housing 11 is closed by being connected to engine 5. A wall 15 separates the interior of motor case 12 from the interior of transmission case 13.

[0029] A dry clutch 16 and a gear case 17 are provided inside the clutch housing 11, and the clutch 16 is connected to the output shaft 5a of the engine 5. A transmission shaft 18 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 planetary gear unit 24, as will be described later.

[0030] 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.

[0031] A cylindrical transmission shaft 19 is provided along the front-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 to be rotatable independently of each other.

[0032] The first motor generator 21 and the second motor generator 22 are arranged side by side in the left-right direction and provided in the right and left parts inside the motor case 12. A transmission shaft 21a of the first motor generator 21 extends forward and enters the inside of the gear case 17. A transmission shaft 22a of the second motor generator 22 extends forward and enters the inside of the gear case 17.

[0033] (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.

[0034] The forward and reverse rotation power of the first motor generator 21 (transmission shaft 21a) is reduced in speed via the transmission gear 21b of the first motor generator 21 and the transmission gear 31, and is then transmitted to the transmission shaft 19.

[0035] (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.

[0036] The power of the engine 5 is accelerated and transmitted from the transmission shaft 18 via the transmission gear 32 and the transmission gear 22b of the second motor generator 22 to the second motor generator 22 (transmission shaft 22a), causing the second motor generator 22 to operate to generate electricity.

[0037] (Configuration of the oil pump 34 that cools the first motor generator 21 and the second motor generator 22) 2, lubricating oil with a relatively low viscosity is stored in the motor case 12. An oil pump 34 is provided at the bottom inside the gear case 17. A drive shaft 34a of the oil pump 34 is provided along the front-rear direction, and a transmission gear 34b is connected to the drive shaft 34a of the oil pump 34.

[0038] A transmission gear 35 is connected to the transmission shaft 18, and the transmission gear 35 is engaged 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.

[0039] When the oil pump 34 is driven, the lubricating oil in the motor case 12 is supplied to the oil pump 34, passes from the oil pump 34 through an oil cooler (not shown), and is supplied 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.

[0040] (Configuration of planetary device 24) 2, the planetary gear 24 is provided on one of the right and left sides of the front part inside the transmission case 13. The planetary gear 24 has an input shaft 23 (corresponding to the first transmission system), a sun gear 24a, a plurality of planet gears 24b and a carrier 24c, a ring gear 24d, a transmission gear 24e, a transmission gear 24f (corresponding to the first transmission system), and the like.

[0041] An input shaft 23 is provided along the front-rear direction and extends forward, and a sun gear 24a and a transmission gear 24f are connected to the input shaft 23. A transmission gear 24e is connected to a carrier 24c. A 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 a ring gear 24d and the planetary gear 24b mesh with each other.

[0042] A transmission gear 38 is connected to the transmission shaft 18, and a transmission gear 39 is connected to the transmission shaft 19. The transmission gear 24e of the planetary device 24 and the transmission gear 38 mesh together, and the transmission gear 24f of the planetary device 24 and the transmission gear 39 mesh together.

[0043] The power of the engine 5 (or the power of the second motor generator 22) is transmitted to the carrier 24c of the planetary gear 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 23 (sun gear 24a) of the planetary gear 24 via the transmission gear 31, the transmission shaft 19, and the transmission gear 39.

[0044] In the planetary gear 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 the speed is changed. A first clutch 25 is provided behind the planetary gear 24, and a ring gear 24d of the planetary gear 24 is connected to the first clutch 25. The combined power in the planetary gear 24 is transmitted from the ring gear 24d of the planetary gear 24 to the first clutch 25 as forward power.

[0045] The transmission gear 31, the transmission shaft 19, the transmission gear 39, the input shaft 23 of the planetary gear 24, and the sun gear 24a are driven in the forward and reverse directions by the forward and reverse rotation of the first motor generator 21. The ring gear 24d of the planetary gear 24 is driven only in the forward direction by the power combined in the planetary gear 24.

[0046] (Configuration of transmission shaft 27) 2, the transmission shaft 27 is provided along the front-rear direction in the other of the right and left parts of the front part inside the transmission case 13. The planetary gear unit 24 and the transmission shaft 27 are provided side by side in the left-right direction in the front part of the inside of the transmission case 13.

[0047] A transmission gear 33 (corresponding to the second transmission system) is connected to the transmission shaft 27, and a transmission gear 39 is in mesh with the transmission gear 33. A second clutch 26 is provided behind the transmission shaft 27, and the transmission shaft 27 is connected to the second clutch 26. The first clutch 25 and the second clutch 26 are arranged side by side in the left-right direction and are provided in the right and left parts of the front part inside the transmission case 13.

[0048] When forward and reverse power is output from the first motor generator 21, the forward and reverse power of the first motor generator 21 is transmitted to the second clutch 26 via the transmission gear 31, the transmission shaft 19 and the transmission gear 39, the transmission gear 33 and the transmission shaft 27.

[0049] (Operating state of first motor generator 21) As shown in Figure 2, when the first clutch 25 is operated to a transmission state, the second clutch 26 is operated to a disengaged state, and the first motor generator 21 is activated, the power of the engine 5 and the power of the first motor generator 21 are transmitted to the planetary gear 24 as described above, and the power combined by the planetary gear 24 is transmitted to the first clutch 25 as forward power.

[0050] The forward power is transmitted to the auxiliary transmission 28 via the first clutch 25 as described below, and is then transmitted from the auxiliary transmission 28 to the rear wheels 2 via the rear wheel differential device 29. The forward power branched between the auxiliary transmission 28 and the rear wheel differential device 29 is transmitted to the front wheel transmission 30, and is then transmitted from the front wheel transmission 30 to the front wheels 1 via the front wheel differential device 20. This causes the work vehicle to move forward. The speed change region of the power combined by the planetary gear 24 corresponds to a relatively high speed forward region.

[0051] When the first clutch 25 is operated to a disengaged state, the second clutch 26 is operated to a transmission state, and the first motor generator 21 outputs reverse power, the reverse power of the first motor generator 21 is transmitted from the transmission shaft 27 to the second clutch 26 as described above.

[0052] The reverse power is transmitted to the auxiliary transmission 28 via the second clutch 26 as described below, and is then transmitted from the auxiliary transmission 28 to the rear wheels 2 via the rear wheel differential device 29. The reverse power branched off between the auxiliary transmission 28 and the rear wheel differential device 29 is transmitted to the front wheel transmission 30, and is then transmitted from the front wheel transmission 30 to the front wheels 1 via the front wheel differential device 20. This causes the work vehicle to move backward. The speed change range of the reverse power transmitted from the first motor generator 21 via the second clutch 26 corresponds to a relatively low speed reverse range.

[0053] When the first clutch 25 is operated to a disengaged state, the second clutch 26 is operated to a transmission state, and the first motor generator 21 outputs forward power, the forward power of the first motor generator 21 is transmitted from the transmission shaft 27 to the second clutch 26, as described above, and transmitted to the rear wheels 2 via the sub-transmission device 28 and the rear wheel differential device 29, and then transmitted to the front wheels 1 via the front wheel transmission device 30 and the front wheel differential device 20. This causes the work vehicle to move forward. The speed change range of the forward power transmitted from the first motor generator 21 via the second clutch 26 corresponds to a relatively low forward speed range.

[0054] When the first clutch 25 and the second clutch 26 are disengaged, the combined power of the planetary gear 24 and the power of the first motor generator 21 are not transmitted to the auxiliary transmission 28, and the work vehicle comes to a halt.

[0055] (Configuration related to the first motor generator 21 and the second motor generator 22) As shown in FIG. 2, a first inverter 41 is provided for the first motor generator 21, a second inverter 42 is provided for the second motor generator 22, and a battery 43 is provided.

[0056] When the first motor generator 21 (second motor generator 22) operates as a motor and transmits power to the transmission shaft 18 (transmission shaft 19), the DC power of the battery 43 is converted into AC power by the first inverter 41 (second inverter 42) 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).

[0057] 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 41 (second inverter 42) and charged into the battery 43 (regeneration mode). Note that a capacitor (not shown) may be used as the battery 43.

[0058] 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.

[0059] 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 and the power of the first motor generator 21 are transmitted to the planetary gear 24. The power of the first motor generator 21 is transmitted to the transmission shaft 27.

[0060] By operating the clutch 16 to the disengaged state, the engine 5 can be stopped and the vehicle can move forward in the drive mode of the first motor generator 21 and the drive mode of the second motor generator 22.

[0061] (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).

[0062] 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.

[0063] (Configuration of the confluence of forward and reverse power) 2, a cylindrical transmission shaft 50 is rotatably attached to the transmission shaft 45, and a transmission gear 55 and a transmission gear 36 are connected to the transmission 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.

[0064] As described above, the power combined by the planetary gear 24 is transmitted as forward power from the planetary gear 24 and the first clutch 25 to the transmission shaft 50. As described above, the forward and reverse powers of the first motor-generator 21 are transmitted to the transmission shaft 50 from the transmission shaft 27 and the second clutch 26.

[0065] (Configuration of the auxiliary transmission 28) As shown in FIG. 2, the auxiliary transmission 28 includes a transmission shaft 53, a transmission gear 37, 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.

[0066] The transmission gear 37 and the high-speed gear 56 are connected to the transmission shaft 53, and the transmission gear 36 and the transmission gear 37 are in mesh. The power combined by the planetary gear 24 is transmitted from the transmission shaft 50 to the transmission shaft 53 as forward power. The forward and reverse powers of the first motor-generator 21 are transmitted from the transmission shaft 50 to the transmission shaft 53.

[0067] The high-speed gear 56 is in mesh with a transmission gear 58a of the transmission shaft 58. 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. The low-speed gear 57 is rotatably attached to the rear wheel output shaft 59, and the low-speed gear 57 is in mesh with a transmission gear 58b of the transmission shaft 58.

[0068] 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 forward (reverse) power of the transmission shaft 53 is transmitted to the rear wheel output shaft 59 at high speed, and then transmitted from the rear wheel output shaft 59 to the rear wheels 2 via the rear wheel differential device 29.

[0069] When the shift member 60 is engaged with the low-speed gear 57, the forward (reverse) 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.

[0070] (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.

[0071] A standard clutch 61 and an accelerating clutch 62 are attached to a transmission shaft 63, and the forward (reverse) power of 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.

[0072] A cylindrical partition 48 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 48 from inside the transmission case 13 and protrudes forward, and a transmission shaft 49 is connected between the front wheel differential device 20 and the front wheel output shaft 64.

[0073] 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 48. The lubricating oil in the motor case 12 is different from the lubricating oil in the transmission case 13 and the gear case 17.

[0074] 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 48 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.

[0075] When the work vehicle is moving forward or backward, if 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 into a transmission state. The forward (reverse) 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 transmitted to the front wheels 1 via the transmission shaft 49 and the front wheel differential device 20, so that the front wheels 1 and rear wheels 2 are driven at the same speed.

[0076] When the work vehicle is moving forward, if 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 the transmission state. The forward 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 49 and the front wheel differential device 20, so that the front wheels 1 are driven at a higher speed than the rear wheels 2.

[0077] (First Alternative Embodiment of the Invention) FIG. 3 shows a configuration in which the transmission shaft 27, transmission gear 33, first clutch 25, second clutch 26, etc. shown in FIG. 2 are eliminated, and a forward / reverse switching device 67 is provided.

[0078] As shown in Fig. 3, the transmission gear 36 (see Fig. 2) of the transmission shaft 50 is eliminated, and the transmission gear 55 of the transmission shaft 50 is engaged with a transmission gear 65 connected to the ring gear 24d of the planetary gear 24. The power combined in the planetary gear 24 is transmitted to the transmission shaft 50 via the transmission gear 65 and the transmission gear 55.

[0079] The forward / reverse switching device 67 has a forward clutch 51, a reverse clutch 52, an intermediate gear 54, etc. The forward clutch 51 and the reverse clutch 52 are attached to the transmission shaft 50. The output gear of the forward clutch 51 meshes with the transmission gear 37 of the transmission shaft 53. A transmission gear 66 is connected to the transmission shaft 53, and the output gear of the reverse clutch 52 meshes with the intermediate gear 54, which meshes with the transmission gear 66.

[0080] When the forward clutch 51 is operated to the transmission state, the power of the transmission shaft 50 is transmitted in a forward state via the forward clutch 51 to the transmission shaft 53, and then transmitted from the transmission shaft 53 to the auxiliary transmission device 28. This causes the work vehicle to move forward.

[0081] When the reverse clutch 52 is operated to the transmission state, the power of the transmission shaft 50 is transmitted in reverse to the transmission shaft 53 via the reverse clutch 52 and the relay gear 54, and then transmitted from the transmission shaft 53 to the auxiliary transmission device 28. This causes the work vehicle to move backward.

[0082] (Second Alternative Embodiment of the Invention) Figure 4 shows a configuration in which the planetary gear 24, transmission shaft 27, first clutch 25, second clutch 26, transmission shaft 50, transmission gears 36, 55, etc. shown in Figure 2 are eliminated. In the configuration shown in Figure 4, the first motor generator 21 performs forward and reverse rotation operations.

[0083] As shown in FIG. 4, a transmission gear 33 that meshes with the transmission gear 39 (see FIG. 2) is connected to a transmission shaft 53. When the first motor generator 21 outputs forward power, the forward power of the first motor generator 21 is transmitted to the auxiliary transmission 28 via the transmission gear 31, the transmission shaft 19, the transmission gear 39, the transmission gear 33, and the transmission shaft 53. This causes the work vehicle to move forward.

[0084] When the first motor generator 21 outputs reverse power, the reverse power of the first motor generator 21 is transmitted to the auxiliary transmission 28 via the transmission gear 31, the transmission shaft 19, the transmission gear 39, the transmission gear 33, and the transmission shaft 53. This causes the work vehicle to move backward.

[0085] (Third Alternative Embodiment of the Invention) In the configuration shown in FIG. 2, when the first clutch 25 is operated to a disengaged state and the second clutch 26 is operated to a transmission state, the first motor generator 21 may be configured to output reverse power but not forward power.

[0086] (Fourth Alternative Embodiment of the Invention) In the configuration shown in FIG. 2, the first clutch 25 may be provided between the transmission gear 39 and the transmission gear 24f of the planetary gear 24, and the second clutch 26 may be provided between the transmission gear 39 and the transmission gear 33.

[0087] In the above-described configuration, when the first clutch 25 is operated into a transmission state, the power of the first motor generator 21 is transmitted to the transmission gear 24f of the planetary device 24 via the transmission gear 31, the transmission shaft 19, the transmission gear 39 and the first clutch 25. When the second clutch 26 is operated to the transmission state, the power of the first motor generator 21 is transmitted to the transmission gear 33 and the transmission shaft 27 via the transmission gear 31, the transmission shaft 19, the transmission gear 39 and the second clutch 26.

[0088] (Fifth Alternative Embodiment of the Invention) In the configuration shown in FIG. 2, the planetary gear 24 and the first clutch 25 may be provided in the upper part of the interior of the transmission case 13, and the transmission shaft 27 and the second clutch 26 may be provided in the lower part of the interior of the transmission case 13. The planetary device 24 and the first clutch 25 may be provided in the lower part inside the transmission case 13, and the transmission shaft 27 and the second clutch 26 may be provided in the upper part inside the transmission case 13. According to the above-described configuration, the planetary device 24 and the first clutch 25, and the transmission shaft 27 and the second clutch 26 are arranged side by side in the vertical direction.

[0089] (Correspondence to claims)-1 The vehicle is equipped with a running device (front wheels 1, rear wheels 2), an engine 5, and a battery 43. The vehicle is provided with a motor (first motor generator 21) that can operate in both forward and reverse directions, and a generator (second motor generator 22) to which the power of the engine 5 is transmitted.

[0090] A first transmission system (input shaft 23, transmission gear 24f) capable of transmitting the power of a motor (first motor generator 21) is provided. A second transmission system (transmission shaft 27, transmission gear 33) is provided that can transmit the power of the motor (first motor generator 21) to the traveling device (front wheels 1, rear wheels 2). The power of the engine 5 and the power of the first transmission system (input shaft 23, transmission gear 24f) are transmitted, and a transmission device (planetary gear 24) is provided that combines the transmitted power and transmits it to the traveling device (front wheels 1, rear wheels 2) as forward power. The vehicle is provided with a switching device (first clutch 25, second clutch 26) that can switch between a forward state in which the power of the transmission device (planetary device 24) is transmitted to the running device (front wheels 1, rear wheels 2) to drive the running device (front wheels 1, rear wheels 2) forward, and a reverse state in which the power of the second transmission system (transmission shaft 27, transmission gear 33) is transmitted to the running device (front wheels 1, rear wheels 2) to drive the running device (front wheels 1, rear wheels 2) backward.

[0091] (Correspondence to claims)-2 The switching device (first clutch 25, second clutch 26) has a first clutch 25 that can be operated to a transmission state in which the power of the transmission device (planetary device 24) is transmitted to the traveling device (front wheels 1, rear wheels 2) and a disconnection state in which the power is disconnected, and a second clutch 26 that can be operated to a transmission state in which the power of the second transmission system (transmission shaft 27, transmission gear 33) is transmitted to the traveling device (front wheels 1, rear wheels 2) and a disconnection state in which the power is disconnected.

[0092] (Correspondence to claims) - 3 A motor gear mechanism (transmission gear 21b, transmission gear 31) is provided to reduce the power of the motor (first motor generator 21) and transmit it to the first transmission system (input shaft 23, transmission gear 24f) and the second transmission system (transmission shaft 27, transmission gear 33). A generator gear mechanism (transmission gear 22b, transmission gear 32) is provided to increase the speed of the power of the engine 5 and transmit it to a generator (second motor generator 22). The motor (first motor generator 21) and the generator (second motor generator 22) are motor generators. [Industrial Applicability]

[0093] 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]

[0094] 1 Front wheel (running gear) 2 Rear wheels (running gear) 5 Engine 21 First motor generator (motor) (motor generator) 21b Transmission gear (motor gear mechanism) 22 Second motor generator (generator) (motor generator) 22b Transmission gear (generator gear mechanism) 23 Input shaft (first transmission system) 24 Planetary gear (transmission gear) 24f Transmission gear (first transmission system) 25 First clutch (switching device) 26 Second clutch (switching device) 27 Transmission shaft (second transmission system) 31 Transmission gear (motor gear mechanism) 32 Transmission gear (generator gear mechanism) 33 Transmission gear (second transmission system) 43 Battery

Claims

1. The vehicle is equipped with a traveling device, an engine, a battery, a motor that can operate in forward and reverse directions, and a generator to which the power of the engine is transmitted, a first transmission system capable of transmitting power of the motor; a second transmission system capable of transmitting power of the motor to the traveling device; a transmission device to which the power of the engine and the power of the first transmission system are transmitted, which combines the transmitted powers and transmits the combined power to the traveling device as forward power; A work vehicle equipped with a switching device that can switch between a forward state in which the power of the transmission device is transmitted to the traveling device to drive the traveling device forward, and a reverse state in which the power of the second transmission system is transmitted to the traveling device to drive the traveling device backward.

2. The switching device is a first clutch operable to be in a transmission state in which the power of the transmission device is transmitted to the traveling device and in a disconnection state in which the power is disconnected; 2. A work vehicle according to claim 1, further comprising a second clutch operable to switch between a transmission state in which power from said second transmission system is transmitted to said traveling device and a disconnection state in which power is disconnected.

3. a motor gear mechanism that reduces the power of the motor and transmits it to the first transmission system and the second transmission system; 2. The work vehicle according to claim 1, further comprising a generator gear mechanism for increasing the speed of the engine power and transmitting it to the generator.

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

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