Work vehicle

Abstract

To provide a hybrid-type service vehicle, in which cooling structures of motor generators and of an inverter are simplified.SOLUTION: A service vehicle is provided with a hybrid mission 4 which has an electric mission part 11 provided with motor generators 21 and 22 and a gear mission part 12 provided with gear transmission mechanisms 18, 19, 20, 23, 24 and 25, which changes a speed of power of an engine 5 and outputs the power to a running device, which is further provided an inverter 45 that activates the motor generators 21 and 22 and a pump 15 that supplies refrigerants for cooling the motor generators 21 and 22 to the inverter 45 to cool the inverter 45.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a hybrid work vehicle equipped with a transmission. [Background technology]

[0002] In a tractor, which is an example of a work vehicle, as disclosed in Patent Document 1, there is a hybrid transmission that has an electric transmission unit equipped with a motor generator and a gear transmission unit equipped with a gear transmission mechanism, and that changes the speed of the engine power and outputs it to the traveling device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-65349 Summary of the Invention [Problem to be solved by the invention]

[0004] When an electric transmission unit is provided as in Patent Document 1, it is necessary to cool the motor generator. Since an inverter is provided for the motor generator, it is also necessary to cool the inverter. The present invention aims to simplify the cooling structure of a motor generator and an inverter in a hybrid work vehicle. [Means for solving the problem]

[0005] The work vehicle of the present invention is provided with a hybrid transmission having an engine, a traveling device, a battery, an electric transmission unit provided with a motor generator, a gear transmission unit provided with a gear transmission mechanism, and configured to change the speed of the engine power and output it to the traveling device, and an inverter that operates the motor generator, the electric transmission unit and the gear transmission unit are separated, and lubricating oil is stored in each of the electric transmission unit and the gear transmission unit; For cooling the motor generator Lubricating oil for the electric transmissiona pump that supplies the inverter with the cooling water to cool the inverter. No pump is provided to supply lubricating oil to the gear transmission mechanism, and an amount of lubricating oil is stored in the gear transmission section such that the liquid level of the lubricating oil in the gear transmission section is higher than the liquid level of the lubricating oil in the electric transmission section.

[0006] According to the present invention, the coolant for cooling the motor generator is supplied to the inverter by the pump, and the inverter is cooled by the coolant. This allows the refrigerant used to cool the motor generator to also be used to cool the inverter, eliminating the need to provide separate refrigerants for cooling the motor generator and the inverter, thereby simplifying the structure. According to the present invention, lubricating oil is used as a refrigerant, and by supplying the lubricating oil to the motor generator, in addition to cooling the motor generator, the bearings and speed increasing / reducing gears for the motor generator can also be lubricated. The electric transmission section and the gear transmission section are separated, and the electric transmission section is used as the lubricating oil storage section, so there is no need for a dedicated oil tank or the like for storing lubricating oil, which is advantageous in terms of simplifying the structure. When lubricating oil is used as the refrigerant, it is preferable to use lubricating oil with a relatively low viscosity in the electric transmission section so as not to create resistance to the motor generator and to facilitate cooling of the motor generator. In the gear transmission section, lubrication takes priority over cooling, so it is preferable to store lubricating oil with a relatively high viscosity so that a film of lubricating oil tends to remain on the gears of the gear transmission mechanism. According to the present invention, even if a lubricating oil that is suitable for cooling the motor generator in the electric transmission section and a lubricating oil that is suitable for lubricating the gear transmission mechanism in the gear transmission section are set, the two lubricating oils will not mix, so the cooling performance of the motor generator and the lubrication performance of the gear transmission mechanism can be easily maintained. If fine debris generated in the gear transmission gets mixed into the lubricating oil that cools the motor generator, it could lead to damage to the insulation in the motor generator. According to the present invention, the electric transmission section and the gear transmission section are separated, which makes it difficult for the above-mentioned contamination to occur, and is also advantageous in terms of improving the durability of the motor generator.

[0007] In the present invention, The aforementioned The motor generator Electric transmission lubricant Available supply Department The pump Electric transmission lubricant is supplied to the inverter, is supplied from the inverter to the supply unit, is supplied from the supply unit to the motor generator, and is supplied from the motor generator to Electric Transmission It is preferable to return to

[0008] Between the motor generator and the inverter, the inverter needs to be cooled to a lower temperature. According to the present invention, Electric transmission lubricant is supplied to the inverter to cool it. lubricating oil is supplied from the inverter to the supply unit, and from the supply unit to the motor generator, cooling the motor generator, and Electric Transmission Return to. lubricating oilAs a result, the inverter is cooled before the motor generator, and therefore the inverter can be cooled sufficiently.

[0009]

[0010]

[0011]

[0012]

[0013]

[0014] In the present invention, it is preferable that an oil cooler is provided in a supply path of lubricating oil from the electric transmission to the inverter.

[0015] According to the present invention, the lubricating oil for the electric transmission is cooled by the oil cooler before being supplied to the inverter, which is advantageous in terms of cooling the inverter and also in terms of cooling the motor generator. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a left side view of the tractor. [Figure 2] FIG. 1 is a schematic diagram showing the interior of a hybrid mission. [Figure 3] FIG. [Figure 4] FIG. 2 is a longitudinal sectional left side view of the inverter. DETAILED DESCRIPTION OF THE INVENTION

[0017] A 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 backward direction, U indicates the upward direction, D indicates the downward direction, R indicates the rightward direction, and L indicates the leftward direction.

[0018] (Overall configuration of the tractor) As shown in Figure 1, the vehicle body 1 is supported by right and left front wheels 2 (corresponding to the running gear) and right and left rear wheels 3 (corresponding to the running gear), a hood 6 is provided at the front of the vehicle body 1, and a driver's section 9 is provided at the rear of the vehicle body 1.

[0019] The machine body 1 has an engine 5, a clutch housing 11 (corresponding to an electric transmission section) (corresponding to a storage section) connected to the rear of the engine 5, a transmission case 12 (corresponding to a gear transmission section) connected to the rear of the clutch housing 11, a front frame 14 connected to the front of the engine 5, etc. The clutch housing 11 and the transmission case 12 form a hybrid transmission 4.

[0020] The front wheels 2 are supported by a front frame 14, and the rear wheels 3 are supported at the rear of a transmission case 12. An engine 5 is covered by a bonnet 6. A 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 2.

[0021] (Clutch housing configuration) As shown in FIG. 2, inside the clutch housing 11, there are provided a clutch 13, a hydraulic pump 15 (corresponding to a pump), a first motor generator 21 (corresponding to a motor generator), and a second motor generator 22 (corresponding to a motor generator).

[0022] A clutch 13 is connected to the output shaft 5a of the engine 5, and a transmission shaft 16 is connected to the clutch 13 and extends from inside the clutch housing 11 to the rear part of the interior of the transmission case 12. A cylindrical shaft 17 is rotatably attached to the transmission shaft 16 and extends from inside the clutch housing 11 to the front part of the interior of the transmission case 12. A hydraulic pump 15 and a first motor-generator 21 are attached to the transmission shaft 16, and a second motor-generator 22 is attached to the cylindrical shaft 17.

[0023] (Transmission case configuration) As shown in FIG. 2, inside the transmission case 12, a planetary gear 18 (corresponding to a gear transmission mechanism), a forward / reverse switching device 19 (corresponding to a gear transmission mechanism), an auxiliary transmission 20 (corresponding to a gear transmission mechanism), a rear wheel differential device 23 (corresponding to a gear transmission mechanism), a front wheel transmission 24 (corresponding to a gear transmission mechanism), a PTO clutch 30, a PTO transmission 25 (corresponding to a gear transmission mechanism), and a PTO shaft 26 are provided.

[0024] The power of the engine 5 (or the power of the first motor generator 21) is transmitted to the planetary gear unit 18, where it is changed in speed, and then transmitted from the forward / reverse switching unit 19 to the auxiliary transmission unit 20, and then transmitted to the rear wheels 3 via the rear wheel differential unit 23. The power branched off just before the rear wheel differential unit 23 is transmitted to the front wheel transmission unit 24, transmitted from the transmission shaft 28 to the front wheel differential unit 29, and transmitted to the front wheels 2 via the front wheel differential unit 29.

[0025] The power of the engine 5 (or the power of the first motor generator 21) is transmitted to the PTO transmission device 25 via the transmission shaft 16 and the PTO clutch 30, where it is changed in speed, and then transmitted to the PTO shaft 26 provided at the rear of the transmission case 12.

[0026] The interior of the clutch housing 11 is separated from the interior of the transmission case 12 by a rear wall 11a of the clutch housing 11 and a front wall 12a of the transmission case 12. A transmission shaft 16 and a cylindrical shaft 17 pass through the wall 11a of the clutch housing 11 and the wall 12a of the transmission case 12.

[0027] (Configuration of planetary gear) As shown in FIG. 2, the planetary device 18 includes a sun gear 18a, a plurality of planetary gears 18b, a carrier 18c, a ring gear 18d, and the like.

[0028] In the planetary device 18, a sun gear 18a is connected to the cylindrical shaft 17. A carrier 18c is connected to the transmission shaft 16, a planetary gear 18b is rotatably supported by the carrier 18c, and the sun gear 18a and the planetary gear 18b are in mesh with each other. A cylindrical shaft 27 is rotatably attached to the transmission shaft 16. A ring gear 18d is connected to the cylindrical shaft 27, and the planetary gear 18b and the ring gear 18d are in mesh with each other.

[0029] The power of the engine 5 (or the power of the first motor generator 21) is transmitted to the carrier 18c of the planetary device 18, and the power of the second motor generator 22 is transmitted to the sun gear 18a of the planetary device 18. In the planetary device 18, the power of the engine 5 (or the power of the first motor generator 21) and the power of the second motor generator 22 are combined and the speed is changed, and this power is transmitted from the ring gear 18d of the planetary device 18 to the cylindrical shaft 27.

[0030] (Configuration of forward / reverse switching device) As shown in FIG. 2, the forward / reverse switching device 19 includes a forward clutch 31, a reverse clutch 32, a transmission shaft 33, an intermediate gear 34, and the like.

[0031] A forward clutch 31 and a reverse clutch 32 are attached to the cylindrical shaft 27. A transmission shaft 33 is provided parallel to the cylindrical shaft 27, and transmission gears 33a and 33b are connected to the transmission shaft 33. The output gear of the forward clutch 31 is engaged with the transmission gear 33a of the transmission shaft 33. The output gear of the reverse clutch 32 is engaged with the relay gear 34, and the relay gear 34 is engaged with the transmission gear 33b of the transmission shaft 33.

[0032] In the forward / reverse switching device 19, when the forward clutch 31 is operated to the transmission state, the power of the cylindrical shaft 27 is transmitted to the transmission shaft 33 in the forward state via the forward clutch 31. When the reverse clutch 32 is operated to the transmission state, the power of the cylindrical shaft 27 is transmitted to the transmission shaft 33 in the reverse state via the reverse clutch 32 and the relay gear 34.

[0033] (Configuration of the auxiliary transmission) As shown in FIG. 2, the sub-transmission device 20 includes a high-speed gear 35, a low-speed gear 36, a cylindrical shaft 37, a transmission shaft 38, a shift member 39, and the like.

[0034] A high-speed gear 35 is connected to the transmission shaft 33. A cylindrical shaft 37 is rotatably attached to the transmission shaft 16, and transmission gears 37a and 37b are connected to the cylindrical shaft 37, with the high-speed gear 35 and the transmission gear 37a of the cylindrical shaft 37 meshing with each other.

[0035] A transmission shaft 38 is provided concentrically with the transmission shaft 33 and the high-speed gear 35, and a shift member 39 is provided on the transmission shaft 38. A low-speed gear 36 is rotatably attached to the transmission shaft 38, and the low-speed gear 36 and a transmission gear 37b of the cylindrical shaft 37 are in mesh with each other.

[0036] In the auxiliary transmission 20, when the shift member 39 is slid and engages with the high-speed gear 35, the transmission shaft 33 and the transmission shaft 38 are connected, and the power of the transmission shaft 33 is transmitted at high speed to the transmission shaft 38. When the shift member 39 is slid and engages with the low-speed gear 36, the power of the transmission shaft 33 is transmitted at low speed to the transmission shaft 38 via the high-speed gear 35, the cylindrical shaft 37, and the low-speed gear 36. The power transmitted to the transmission shaft 38 is transmitted from the rear wheel output shaft 40 to the rear wheel differential device 23 and from the rear wheel differential device 23 to the rear wheels 3 .

[0037] (Front wheel transmission configuration) As shown in FIG. 2, the front wheel transmission 24 includes a standard clutch 41, a speed-increasing clutch 42, a transmission shaft 43, a front wheel output shaft 44, and the like.

[0038] A standard clutch 41 and an accelerating clutch 42 are attached to a transmission shaft 43, and power from the rear wheel output shaft 40 is transmitted to the transmission shaft 43. A front wheel output shaft 44 is provided parallel to the transmission shaft 43, and transmission gears 44a and 44b are connected to the front wheel output shaft 44. The output gear of the standard clutch 41 meshes with the transmission gear 44a of the front wheel output shaft 44, and the output gear of the accelerating clutch 42 meshes with the transmission gear 44b of the front wheel output shaft 44.

[0039] When the front wheels 2 are operated within a set angle range to the right or left from the straight ahead position, the standard clutch 41 in the front wheel transmission 24 is operated to a transmission state. The power of the rear wheel output shaft 40 is transmitted to the front wheel output shaft 44 via the transmission shaft 43 and the standard clutch 41, and then transmitted to the front wheels 2 via the transmission shaft 28 and the front wheel differential device 29, so that the front wheels 2 and rear wheels 3 are driven at the same speed.

[0040] When the front wheels 2 are steered to the right or left beyond the right or left set angle, the speed increasing clutch 42 in the front wheel transmission 24 is operated into a transmission state. The power of the rear wheel output shaft 40 is transmitted to the front wheel output shaft 44 via the transmission shaft 43 and the speed-increasing clutch 42, and then transmitted to the front wheels 2 via the transmission shaft 28 and the front wheel differential device 29, so that the front wheels 2 are driven at a higher speed than the rear wheels 3.

[0041] (Configuration of the first motor generator and the second motor generator) As shown in FIG. 2, an inverter 45 and a battery 46 are provided for the first motor generator 21 and the second motor generator 22.

[0042] When the first motor generator 21 (second motor generator 22) operates as a motor and supplies power to the transmission shaft 16 (cylindrical shaft 17), the DC power of the battery 46 is converted to AC power by the inverter 45 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).

[0043] When the first motor generator 21 (second motor generator 22) is driven to operate as a generator, the AC power generated by the first motor generator 21 (second motor generator 22) is converted into DC power by the inverter 45 and charged into the battery 46 (charging mode).

[0044] A control device (not shown) sets the charging mode and driving mode of the first motor generator 21 and the charging mode and driving mode of the second motor generator 22 based on the state of the working device (not shown) attached to the machine body 1, the running state of the machine body 1, etc.

[0045] In this case, the basic running state is one in which the first motor generator 21 is set to the charging mode and the second motor generator 22 is set to the driving mode. In the basic driving state, the power of the engine 5 is transmitted to the carrier 18c of the planetary gear 18, and the power of the second motor generator 22 is transmitted to the sun gear 18a of the planetary gear 18. In the planetary gear 18, the power of the engine 5 and the power of the second motor generator 22 are combined and changed in speed, and this power is transmitted from the ring gear 18d of the planetary gear 18 to the cylindrical shaft 27.

[0046] By operating the clutch 13 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 second motor generator 22.

[0047] (Lubricant for clutch housing and transmission case) 2, a lubricating oil (corresponding to a refrigerant) with a relatively low viscosity is stored in the bottom of the clutch housing 11. The amount of the lubricating oil is set so that the oil level L1 of the lubricating oil stored in the clutch housing 11 is low enough not to come into contact with the first motor-generator 21 and the second motor-generator 22.

[0048] Lubricating oil having a higher viscosity than the lubricating oil in the clutch housing 11 is stored in the transmission case 12. A sufficient amount of lubricating oil is stored in the transmission case 12 so that the oil level of the lubricating oil stored in the transmission case 12 is higher than the oil level L1 of the lubricating oil in the clutch housing, and the transmission case 12 serves as an oil bath.

[0049] With the above configuration, the lubricating oil stored in the clutch housing 11 (lubricating oil for cooling the first motor generator 21 and the second motor generator 22) is set to be different from the lubricating oil stored in the transmission case 12.

[0050] The interior of the clutch housing 11 is separated from the interior of the transmission case 12 by a rear wall 11a of the clutch housing 11 and a front wall 12a of the transmission case 12. This prevents the lubricating oil stored in the clutch housing 11 (lubricating oil for cooling the first motor-generator 21 and the second motor-generator 22) from mixing with the lubricating oil stored in the transmission case 12.

[0051] (Configuration related to cooling and lubrication of the first motor generator and the second motor generator) As shown in FIG. 2, the hydraulic pump 15 is driven by the transmission shaft 16, and the lubricating oil in the clutch housing 11 is sucked into the hydraulic pump 15 through a filter 47 with relatively fine mesh.

[0052] The lubricating oil sucked into the hydraulic pump 15 is supplied from the hydraulic pump 15 through a supply path 48 to an oil cooler 50 where it is cooled. The lubricating oil cooled in the oil cooler 50 is supplied to the inverter 45 through a supply path 49 where it cools the inverter 45.

[0053] In this embodiment, a plurality of injection nozzles 53 (corresponding to supply units) are provided inside the clutch housing 11 so as to face each part of the first motor generator 21 and each part of the second motor generator 22, and an injection pump 52 (corresponding to the supply unit) is provided for the injection nozzles 53. In this case, it is also possible to configure the system so that the injection pump 52 is not provided and lubricating oil is supplied from the injection nozzles 53 to each part of the first motor generator 21 and each part of the second motor generator 22.

[0054] The lubricating oil that has cooled the inverter 45 is supplied to the injection pump 52 through a supply path 51, and is then supplied from the injection pump 52 to an injection nozzle 53 through a supply path 54. The lubricating oil is supplied from the injection nozzle 53 to each part of the first motor generator 21 and each part of the second motor generator 22, thereby cooling and lubricating the first motor generator 21 and the second motor generator 22.

[0055] The lubricating oil that has cooled and lubricated the first motor generator 21 and the second motor generator 22 naturally falls from the first motor generator 21 and the second motor generator 22 and returns to the bottom of the clutch housing 11.

[0056] With the above configuration, the hydraulic pump 15 supplies lubricating oil for the clutch housing 11 (electric transmission portion) to the inverter 45, and then from the inverter 45 to the injection pump 52 (supply portion) and the injection nozzle 53 (supply portion). Lubricating oil is supplied from the injection pump 52 (supply section) and the injection nozzle 53 (supply section) to the first motor generator 21 and the second motor generator 22, and then returned from the first motor generator 21 and the second motor generator 22 to the clutch housing 11 (electric transmission section). An oil cooler 50 for cooling the lubricating oil is provided in supply paths 48 and 49 for the lubricating oil from the clutch housing 11 (electric transmission section) to the inverter 45.

[0057] (Inverter configuration) As shown in Figures 3 and 4, the inverter 45 has a capacitor 55, an IGBT 56 which is an example of a power transistor, a resistor 57, etc., and the capacitor 55, the IGBT 56, the resistor 57, etc. are housed in a case 58.

[0058] The case 58 has a base member 58a and a lid portion 58b. A cooling path 59 through which lubricating oil passes is provided inside the base member 58a of the case 58, and the cooling path 59 has a first portion 59a, a second portion 59b, and a third portion 59c.

[0059] The first portion 59a of the cooling path 59 is formed along the front-to-rear direction from the front of the base member 58a of the case 58 to the rear, and the supply path 49 (see Figure 2) is connected to the front of the first portion 59a of the cooling path 59.

[0060] The second portion 59b of the cooling path 59 is formed in the front-to-rear direction, turning 180 degrees from the rear of the first portion 59a of the cooling path 59 and extending forward. The third portion 59c of the cooling path 59 is formed in the front-to-rear direction, turning 180 degrees from the front of the second portion 59b of the cooling path 59 and extending backward, and the supply path 51 (see FIG. 2) is connected to the rear of the third portion 59c of the cooling path 59.

[0061] A capacitor 55 is attached to a substrate member 58a of the case 58 in a portion corresponding to an upper portion of the first portion 59a and the second portion 59b of the cooling path 59. An IGBT 56 and a resistor 57 are attached to a portion corresponding to an upper portion of the third portion 59c of the cooling path 59 of the substrate member 58a of the case 58.

[0062] 4, an opening 59d is formed in the upper part of a third portion 59c of the cooling path 59, and the IGBT 56 is provided in the opening 59d of the cooling path 59. A large number of pin fins 56a serving as a heat sink are provided below the IGBT 56 and face downward, and the pin fins 56a of the IGBT 56 extend from the opening 59d of the cooling path 59 into the third portion 59c. A protrusion 59e that protrudes upward is provided in the lower part of the third portion 59c of the cooling path 59 at a portion facing the opening 59d of the cooling path 59.

[0063] 2, 3, and 4, the lubricating oil is supplied from the oil cooler 50 through the supply path 49 to the first portion 59a of the cooling path 59. The lubricating oil passes from the first portion 59a to the second portion 59b of the cooling path 59, thereby cooling the condenser 55.

[0064] The lubricating oil enters the third part 59c from the second part 59b of the cooling path 59, and the protrusion 59e of the cooling path 59 brings the lubricating oil close to the pin fins 56a of the IGBT 56, thereby sufficiently cooling the IGBT 56 (absorbing heat from the IGBT 56 by the lubricating oil).

[0065] The lubricating oil that has passed through the protruding portion 59e of the cooling path 59 reaches the position of the resistor 57 and cools the resistor 57. The lubricating oil that comes out of the third portion 59c of the cooling path 59 is supplied to the injection pump 52 through the supply path 51.

[0066] (First Alternative Embodiment of the Invention) Instead of providing the first motor generator 21 and the second motor generator 22, a single motor generator (not shown) may be provided in the clutch housing 11. In this configuration, the motor generator may be provided on the transmission shaft 16.

[0067] (Second Alternative Embodiment of the Invention) Instead of storing the lubricating oil at the bottom of the clutch housing 11, an oil tank (not shown) may be provided separately from the clutch housing 11 to store the lubricating oil.

[0068] (Third Alternative Embodiment of the Invention) A case (not shown) covering the first motor generator 21 (second motor generator 22) may be provided separately from the clutch housing 11, and the first motor generator 21 (second motor generator 22) may be cooled by passing a refrigerant through the inside of the case. According to this configuration, the cooling water can be used as a refrigerant for cooling the first motor generator 21 (second motor generator 22) and the inverter 45.

[0069] (Fourth Alternative Embodiment of the Invention) The hydraulic pump 15 and the injection pump 52 may be eliminated, and an electric oil pump (not shown) (corresponding to a pump) may be provided in the supply path 49. With this configuration, the pressure of the lubricating oil can be set to a high pressure downstream from the supply path 49, so that the lubricating oil flows smoothly through the cooling path 59 of the inverter 45, and even without the injection pump 52, the lubricating oil is supplied effortlessly from the injection nozzle 53 to each part of the first motor generator 21 and each part of the second motor generator 22.

[0070] (Fifth Alternative Embodiment of the Invention) A pump (not shown) and a supply path (not shown) that supplies the lubricating oil stored in the clutch housing 11 to the inverter 45 for cooling purposes, and a pump (not shown) and a supply path (not shown) that supplies the lubricating oil stored in the clutch housing 11 to the first motor generator 21 and the second motor generator 22 for cooling purposes may be provided separately and independently of each other. As a result, the lubricating oil stored in the clutch housing 11 is used in common to cool the inverter 45 and the first motor-generator 21 and the second motor-generator 22. [Industrial Applicability]

[0071] The present invention can be applied not only to tractors, but also to work vehicles that carry and transport cargo, 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 front and rear wheels. [Explanation of symbols]

[0072] 2 Front wheels (running gear) 3 Rear wheels (running gear) 4 Hybrid Mission 5 Engine 11 Clutch housing (electric transmission part) (storage part) 12 Transmission case (gear transmission section) 15 Hydraulic pump (pump) 18 Planetary gear (gear transmission mechanism) 19 Forward / reverse switching device (gear transmission mechanism) 20 Sub-transmission device (gear transmission mechanism) 21 First motor generator (motor generator) 22 Second motor generator (motor generator) 23 Rear wheel differential (gear transmission mechanism) 24 Front wheel transmission (gear transmission mechanism) 25 PTO transmission (gear transmission mechanism) 45 inverter 46 Battery 48 Supply Channels 49 Supply Channels 50 Oil cooler 52 Injection pump (supply section) 53 Injection nozzle (supply section)

Claims

1. An engine, a running gear, a battery, a hybrid transmission having an electric transmission section provided with a motor generator and a gear transmission section provided with a gear transmission mechanism, which changes the speed of the power of the engine and outputs it to the traveling device; an inverter that operates the motor generator, The electric transmission unit and the gear transmission unit are separated, Lubricating oil is stored in each of the electric transmission unit and the gear transmission unit, a pump that supplies lubricating oil for the electric transmission unit, which is used to cool the motor generator, to the inverter to cool the inverter; A work vehicle in which a pump for supplying lubricating oil to the gear transmission mechanism is not provided, and a quantity of lubricating oil is stored in the gear transmission section such that the liquid level of the lubricating oil in the gear transmission section is higher than the liquid level of the lubricating oil in the electric transmission section.

2. The motor generator is provided with a supply unit capable of supplying lubricating oil to the electric transmission unit, 2. The work vehicle according to claim 1, wherein the pump supplies lubricating oil for the electric transmission to the inverter, from the inverter to the supply unit, from the supply unit to the motor generator, and from the motor generator to the electric transmission.

3. 3. The work vehicle according to claim 2, wherein an oil cooler is provided in a supply path of lubricating oil from the electric transmission to the inverter.

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