Work vehicle

Abstract

To form a structure which can cool a motor and an inverter efficiently in a service vehicle provided with the motor for supplying power to travel devices.SOLUTION: A service vehicle includes: a battery 46; motors 21, 22 which supply power to travel devices; an inverter 45 which operates the motors 21, 22; a first storage part 11 for storing a first refrigerant; a second storage part 61 for storing a second refrigerant; a first pump 15; and a second pump 62. The first refrigerant of the first storage part 11 is supplied to the motors 21, 22 by the first pump 15 and returns from the motors 21, 22 to the first storage part 11. The second refrigerant of the second storage part 61 is supplied to the inverter 45 by the second pump 62 and returns from the inverter 45 to the second storage part 61.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to the configuration of a traveling drive system for a work vehicle. [Background technology]

[0002] BACKGROUND ART As disclosed in Patent Document 1, a tractor, which is an example of a work vehicle, includes a motor and a battery that supply power to a 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 a motor is provided to supply power to the travel device as in Patent Document 1, the motor needs to be cooled, and the inverter that operates the motor also needs to be cooled. The present invention has an object to provide a configuration that allows efficient cooling of the motor and inverter in a work vehicle provided with a motor that supplies power to a traveling device. [Means for solving the problem]

[0005] The work vehicle of the present invention includes a traveling device, a battery, and a power supply for the traveling device. Motor generator and the above Motor generator a first reservoir for storing a first refrigerant, a second reservoir for storing a second refrigerant, a first pump, and a second pump, and the first refrigerant in the first reservoir is pumped to the Motor generator and Motor generator the second refrigerant in the second storage portion is supplied to the inverter by the second pump and returned to the second storage portion from the inverter. The hybrid transmission is configured as follows: an engine is provided separately from the motor generator; the hybrid transmission has an electric transmission unit that houses the motor generator and a gear transmission unit that is provided with a gear transmission mechanism, and changes the speed of the engine's power and outputs it to the traveling device; the first storage unit is the electric transmission unit; the first refrigerant is lubricating oil stored in the electric transmission unit; the electric transmission unit and the gear transmission unit are partitioned, and the lubricating oil is stored in the gear transmission unit; no pump is provided for supplying the lubricating oil of the gear transmission unit to the gear transmission mechanism; and an amount of lubricating oil stored in the gear transmission unit is such that the liquid level of the lubricating oil in the gear transmission unit is higher than the liquid level of the lubricating oil in the electric transmission unit.

[0006] Powers the running gear Motor generator Generally, the inverter is more likely to become hotter than the drive load. Motor generator A relatively large temperature difference occurs between the inverter and the power supply. According to the present invention, a first reservoir for storing a first refrigerant and a second reservoir for storing a second refrigerant are provided, and the first refrigerant in the first reservoir is pumped by a first pump. Motor generator The second refrigerant in the second storage section is supplied to the inverter by the second pump and returns to the second storage section.

[0007] According to the present invention, Motor generator Since the first refrigerant for cooling the inverter and the second refrigerant for cooling the inverter are provided separately, Motor generator The first refrigerant can be set to suit the Motor generator It is possible to set a second refrigerant that is suitable for inverters with lower temperatures than the first refrigerant. This means: Motor generator (first refrigerant) and inverter (second refrigerant) do not affect each other, Motor generator The cooling of the cooling fan and the inverter can be performed efficiently. According to the present invention, by using a cooling oil suitable for the motor generator, which has a relatively high temperature, as the first refrigerant, it is advantageous in that the motor generator and the inverter can be cooled efficiently. According to the present invention, lubricating oil is used as cooling oil, and by supplying lubricating oil to the motor generator, in addition to cooling the motor generator, it is possible to lubricate the bearings and speed increasing / reducing gears for the motor generator. According to the present invention, when an electric transmission section that houses a motor generator is provided, the electric transmission section serves as the first storage section for lubricating oil, 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. According to the present invention, an engine is provided separately from the motor generator, and a hybrid transmission having an electric transmission section and a gear transmission section is provided. This is advantageous in that the motor generator and the inverter can be cooled efficiently in a hybrid work vehicle. In the electric transmission, it is preferable to use lubricating oil with a relatively low viscosity 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 use a lubricating oil with a relatively high viscosity so that a film of lubricating oil is more likely 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.

[0008] In the present invention And, in front The second refrigerant is preferably cooling water.

[0009] According to the present invention And, 2As a refrigerant, Motor generatorBy setting the cooling water temperature suitable for the inverter, Motor generator This is advantageous in that the cooling of the cooling unit and the inverter can be performed efficiently.

[0010] In the present invention, Electric transmission lubricant from the first pump to the Motor generator The first supply system supplies Electric transmission lubricant It is preferable that the inverter further includes a cooling unit that cools the cooling water in the second reservoir, and a second supply system through which the cooling water in the second reservoir is supplied from the second pump to the inverter, includes a radiator that cools the cooling water.

[0011] According to the present invention, the cooling section Electric transmission lubricant is cooled, Electric transmission lubricant but Motor generator Because it is supplied to Motor generator This is advantageous in terms of cooling. According to the present invention, the coolant is cooled in the radiator, and low-temperature coolant is supplied to the inverter, which is advantageous in terms of cooling the inverter.

[0012] In the present invention, the cooling unit is provided across the first supply system and the second supply system, Electric transmission lubricant It is preferable that the cooling water supply system has a heat exchanger for exchanging heat between the cooling water and the cooling water.

[0013] According to the present invention, in the heat exchanger, Electric transmission lubricant Heat is exchanged between the cooling water in the first supply system and the cooling water in the second supply system. Electric transmission lubricant The heat of the second supply system is absorbed by the cooling water of the first supply system. Electric transmission lubricant The temperature of the cooling water in the second supply system is suppressed (or the heat of the cooling water in the first supply system is Electric transmission lubricant This keeps the temperature of the cooling water in the second supply system low. Motor generator This is advantageous in that the cooling of the cooling unit and the inverter can be performed efficiently.

[0014] Electric transmission lubricant When an oil cooler that cools the first supply system is installed separately from the heat exchanger, the heat exchanger Electric transmission lubricant Since heat exchange occurs between the cooling water of the first supply system and the cooling water of the second supply system, the load on the oil cooler is reduced, and the oil cooler can be made smaller. The heat exchanger is used to Electric transmission lubricant Heat exchange occurs between the cooling water in the second supply system and the Electric transmission lubricant If is cooled sufficiently, Electric transmission lubricant This eliminates the need for an oil cooler.

[0015] In the present invention, the cooling unit Electric transmission lubricant It is preferable that the engine has an oil cooler for cooling the engine.

[0016] According to the present invention, the oil cooler Electric transmission lubricant is directly cooled, and the low temperature Electric transmission lubricant but Motor generator Because it is supplied to Motor generator This is advantageous in terms of cooling.

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024] [Brief explanation of the drawings]

[0025] [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] 3 is a schematic diagram showing an outline of cooling and lubrication of a first motor generator and a second motor generator, and an outline of cooling of an inverter. FIG. [Figure 4] FIG. [Figure 5] FIG. 2 is a longitudinal sectional left side view of the inverter. DETAILED DESCRIPTION OF THE INVENTION

[0026] A tractor, which is an example of a work vehicle, is shown in Figures 1 to 5. In Figures 1 to 5, 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.

[0027] (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.

[0028] The machine body 1 has an engine 5, a clutch housing 11 (corresponding to an electric transmission section) (corresponding to a first 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.

[0029] 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.

[0030] (Clutch housing configuration) As shown in FIG. 2, inside the clutch housing 11, there are a clutch 13, a hydraulic pump 15 (corresponding to a first pump), a first motor generator 21 (corresponding to a motor generator), and a )、Second motor generator 22 (corresponding to a motor generator) )but It is provided.

[0031] 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.

[0032] (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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] (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.

[0037] 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.

[0038] 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.

[0039] (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.

[0040] 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 meshes with the transmission gear 33a of the transmission shaft 33. The output gear of the reverse clutch 32 meshes with the relay gear 34, and the relay gear 34 meshes with the transmission gear 33b of the transmission shaft 33.

[0041] 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.

[0042] (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.

[0043] 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.

[0044] 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.

[0045] 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 .

[0046] (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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] (Configuration of the first motor generator and the second motor generator) As shown in FIGS. 2 and 3, an inverter 45 and a battery 46 are provided for the first motor generator 21 and the second motor generator 22.

[0051] 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).

[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 inverter 45 and charged into the battery 46 (charging mode). Note that a capacitor (not shown) may be used as the battery 46.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] (Lubricant for clutch housing and transmission case) As shown in FIG. 3, a lubricating oil having a relatively low viscosity (corresponding to a first refrigerant) is applied to the bottom of the clutch housing 11. )but The amount of lubricating oil stored in the clutch housing 11 is set so that the oil level L1 is low enough not to come into contact with the first motor-generator 21 and the second motor-generator 22.

[0057] 2, 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 11, and the transmission case 12 serves as an oil bath.

[0058] 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) and the lubricating oil stored in the transmission case 12 are set to be different.

[0059] 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.

[0060] (Configuration related to cooling and lubrication of the first motor generator and the second motor generator) 3, a hydraulic pump 15, an oil cooler 48 (corresponding to a cooling unit), an injection pump 49, and an injection nozzle 50 are provided for the first motor generator 21 and the second motor generator 22. A heat exchanger 60 (corresponding to a cooling unit) is provided for the first motor generator 21, the second motor generator 22, and the inverter 45.

[0061] 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 relatively fine filter 47. The lubricating oil sucked into the hydraulic pump 15 is supplied from the hydraulic pump 15 through a path 51 (corresponding to the first supply system) to a heat exchanger 60, and from the heat exchanger 60 through a path 52 (corresponding to the first supply system) to be supplied to an oil cooler 48 where it is cooled.

[0062] The lubricating oil cooled by the oil cooler 48 passes through a path 53 (corresponding to a first supply system) and is supplied to an injection pump 49. A plurality of injection nozzles 50 are provided inside the clutch housing 11 so as to face respective parts of the first motor generator 21 and the second motor generator 22.

[0063] Lubricating oil from the injection pump 49 is supplied to the injection nozzle 50 through a path 54. The lubricating oil is supplied from the injection nozzle 50 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.

[0064] 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.

[0065] With the above configuration, the lubricating oil (first refrigerant) (cooling oil) in the clutch housing 11 (first reservoir) is pumped to the first motor generator 2 by the hydraulic pump 15 (first pump). 1st place and second motor generator 2 2 to Supplied, 1st motor generator 2 1st place and second motor generator 2 2 or Then, the oil returns to the clutch housing 11 (first storage section).

[0066] The lubricating oil (first refrigerant) in the clutch housing 11 (first reservoir) )but From the hydraulic pump 15 (first pump) to the first motor generator 2 1st place and second motor generator 2 2 to An oil cooler 48 for cooling the lubricating oil (first refrigerant) (cooling oil) is provided in the supply paths 51, 52, 53 (first supply system).

[0067] (Inverter cooling configuration) 3, a cooling water tank 61 (corresponding to the second storage section), a water pump 62 (corresponding to the second pump), and a radiator 63 are provided for the inverter 45. Cooling water (corresponding to the second refrigerant) is stored in the cooling water tank 61, and the water pump 62 is driven by the power of the engine 5.

[0068] The cooling water in the cooling water tank 61 is sucked in by the water pump 62, supplied from the water pump 62 to the heat exchanger 60 through a path 64 (corresponding to the second supply system), and then supplied from the heat exchanger 60 to the radiator 63 through a path 65 (corresponding to the second supply system) where it is cooled.

[0069] The cooling water cooled by the radiator 63 passes through a path 66 (corresponding to a second supply system) and is supplied to the inverter 45 to cool the inverter 45. After cooling the inverter 45, the cooling water returns to the cooling water tank 61 through a path 67.

[0070] Lubricating oil in the clutch housing 11 is supplied to the heat exchanger 60 via the hydraulic pump 15 and a passage 51 , and cooling water in a cooling water tank 61 is supplied to the heat exchanger 60 via a water pump 62 and a passage 64 .

[0071] In the heat exchanger 60, heat is exchanged between the lubricating oil in the clutch housing 11 and the cooling water in the cooling water tank 61 (the heat of the lubricating oil in the clutch housing 11 is absorbed by the cooling water in the cooling water tank 61, or the heat of the cooling water in the cooling water tank 61 is absorbed by the lubricating oil in the clutch housing 11).

[0072] With the above configuration, the cooling water (second refrigerant) in the cooling water tank 61 (second storage unit) is supplied to the inverter 45 by the water pump 62 (second pump), and then returned from the inverter 45 to the cooling water tank 61 (second storage unit).

[0073] A radiator 63 for cooling the cooling water (second refrigerant) is provided in paths 64, 65, 66 (second supply system) through which the cooling water (second refrigerant) in the cooling water tank 61 (second storage section) is supplied from the water pump 62 (second pump) to the inverter 45.

[0074] A heat exchanger 60 for exchanging heat between lubricating oil (first refrigerant) (cooling oil) and cooling water (second refrigerant) is provided across paths 51, 52, 53 (first supply system) and paths 64, 65, 66 (second supply system). Lubricating oil (first refrigerant) )of As a cooling configuration, a cooling section having an oil cooler 48 and a heat exchanger 60 is provided.

[0075] When a configuration is used in which heat exchange between the lubricating oil in the clutch housing 11 and the cooling water in the cooling water tank 61 is performed by the heat exchanger 60 (a configuration in which the heat of the lubricating oil in the clutch housing 11 is absorbed by the cooling water in the cooling water tank 61), it is possible to reduce the size of the oil cooler 48. If the above-mentioned heat exchange is performed sufficiently, it is not necessary to provide the oil cooler 48.

[0076] (Inverter configuration) As shown in Figures 4 and 5, 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.

[0077] The case 58 has a base portion 58a and a lid portion 58b. A cooling path 59 through which lubricating oil passes is provided inside the base portion 58a of the case 58, and the cooling path 59 has a first portion 59a, a second portion 59b, and a third portion 59c.

[0078] The first portion 59a of the cooling path 59 is formed in the front-to-rear direction from the front of the base portion 58a of the case 58 to the rear, and a path 66 (see Figure 3) is connected to the front of the first portion 59a of the cooling path 59.

[0079] 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 rearward, and a path 67 (see FIG. 3) is connected to the rear of the third portion 59c of the cooling path 59.

[0080] A capacitor 55 is attached to a substrate portion 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 substrate portion 58a of the case 58 in a portion corresponding to an upper portion of the third portion 59c of the cooling path 59.

[0081] 5, 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.

[0082] 3, 4, and 5, cooling water is supplied from radiator 63 through path 66 to first portion 59a of cooling path 59. As the cooling water passes from first portion 59a to second portion 59b of cooling path 59, condenser 55 is cooled.

[0083] The cooling water flows from the second portion 59b to the third portion 59c of the cooling path 59, and is brought close to the pin fins 56a of the IGBT 56 by the protrusion 59e of the cooling path 59, so that the IGBT 56 is cooled sufficiently.

[0084] The cooling water 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 cooling water that leaves the third portion 59c of the cooling path 59 returns to the cooling water tank 61 through a path 67.

[0085] (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.

[0086] (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) (corresponding to a first storage section) may be provided separately from the clutch housing 11 to store the lubricating oil.

[0087] (Third Alternative Embodiment of the Invention) The injection pump 49 may be eliminated, and lubricating oil may be supplied to each part of the first motor-generator 21 and each part of the second motor-generator 22 from the injection nozzle 50.

[0088] (Fourth Alternative Embodiment of the Invention) The hydraulic pump 15 and the injection pump 49 may be eliminated, and an electric oil pump (not shown) (corresponding to the first pump) may be provided in the paths 53 and 54. According to this configuration, even if the injection pump 49 is not provided, the lubricating oil is supplied from the injection nozzle 50 to each part of the first motor generator 21 and each part of the second motor generator 22 without any difficulty.

[0089] (Fifth Alternative Embodiment of the Invention) A heat exchanger 60 may be configured to be provided across the path 53 and the path 66 . According to this configuration, the heat exchanger 60 is provided between the oil cooler 48 and the injection pump 49 , and between the radiator 63 and the inverter 45 .

[0090] A heat exchanger 60 may be configured to be provided across the path 54 and the path 67 . According to this configuration, the heat exchanger 60 is provided between the injection pump 49 and the injection nozzle 50 , and between the inverter 45 and the cooling water tank 61 .

[0091] The heat exchanger 60 may be configured to be provided between the paths 51 and 52 and the path 66, or between the paths 51 and 52 and the path 67. The heat exchanger 60 may be configured to be provided between the path 53 and the paths 64 and 65, or between the path 53 and the path 67. The heat exchanger 60 may be configured to be provided between the path 54 and the paths 64 and 65, or between the path 54 and the path 66.

[0092] (Sixth 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 first refrigerant through the inside of the case.

[0093] According to this configuration, the cooling water can be used as the first refrigerant that cools the first motor generator 21 (second motor generator 22). When cooling water is used as the first refrigerant, it is preferable to provide the heat exchanger 60 between any one of the paths 51 to 54 and the path 67.

[0094] As described above, when cooling water is used as the first refrigerant to cool the first motor generator 21 (second motor generator 22), cooling water containing an additive different from that of the first refrigerant may be used as the second refrigerant to cool the inverter 45, thereby making the first refrigerant (cooling water) and the second refrigerant (cooling water) different. In this configuration, cooling oil may be used as the second refrigerant instead of cooling water.

[0095] (Seventh Alternative Embodiment of the Invention) The engine 5 may be eliminated, and one or more motors (not shown) may be provided instead of the first motor generator 21 and the second motor generator 22, thereby forming an electric tractor. According to this configuration, it is also possible to configure the transmission case 12 so that the planetary gear 18 and the forward / reverse switching device 19 are not provided. [Industrial Applicability]

[0096] 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]

[0097] 2 Front wheels (running gear) 3 Rear wheels (running gear) 4 Hybrid Mission 5 Engine 11 Clutch housing (electric transmission section) (first storage section) 12 Transmission case (gear transmission section) 15 Hydraulic pump (first 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 48 Oil cooler (cooling section) Route 51 (1st supply system) Route 52 (1st supply system) Route 53 (1st supply system) 60 Heat exchanger (cooling section) 61 Cooling water tank (second storage section) 62 Water pump (second pump) 63 Radiator 64 Route (Second Supply System) Route 65 (Second Supply System) Route 66 (Second Supply System)

Claims

1. a traveling device, a battery, a motor generator that supplies power to the traveling device, and an inverter that operates the motor generator; The cooling system includes a first reservoir for storing a first refrigerant, a second reservoir for storing a second refrigerant, a first pump, and a second pump, the first refrigerant in the first reservoir is supplied to the motor generator by the first pump and returned from the motor generator to the first reservoir; the second refrigerant in the second storage portion is supplied to the inverter by the second pump and returned from the inverter to the second storage portion, an engine is provided separately from the motor generator, a hybrid transmission having an electric transmission section that houses the motor generator and a gear transmission section that is provided with a gear transmission mechanism, and that changes the speed of the power of the engine and outputs it to the traveling device; the first storage section is the electric transmission section, the first refrigerant is lubricating oil stored in the electric transmission unit, The electric transmission unit and the gear transmission unit are separated, and lubricating oil is stored in the gear transmission unit. 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. A work vehicle as described in claim 1, wherein the second refrigerant is cooling water.

3. a first supply system through which the lubricating oil for the electric transmission unit is supplied from the first pump to the motor generator, and a cooling unit that cools the lubricating oil for the electric transmission unit is provided in the first supply system; 3. The work vehicle according to claim 2, wherein a second supply system through which the cooling water in the second reservoir is supplied from the second pump to the inverter is provided with a radiator that cools the cooling water.

4. The cooling unit is 4. The work vehicle according to claim 3, further comprising a heat exchanger provided across the first supply system and the second supply system, for exchanging heat between the lubricating oil of the electric transmission and the cooling water.

5. The cooling unit is 5. The work vehicle according to claim 3, further comprising an oil cooler for cooling lubricating oil in the electric transmission.

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