Electric vehicle driving device

Abstract

To obtain an electric vehicle driving device that can be efficiently cooled, decreases weight and size, and facilitates assembling to an electric vehicle.SOLUTION: An electric vehicle driving device is equipped with a motor with a rotary shaft, a gear box that stores a deceleration mechanism coupled to the rotary shaft and a differential mechanism coupled to the deceleration mechanism, a final gear shaft that is coupled to the differential mechanism on one side, a support structure that supports the other side of the final gear shaft and is fixed to the motor, and a radiator that cools the motor. The motor and the final gear shaft are oppositely disposed at an interval. The gear box is provided on one side in an X-direction of the motor and the final gear shaft, and the support structure is provided on the other side in the X-direction of the motor and the final gear shaft. The radiator is provided on any one-way side of the other side in a Y-direction, one side in a Z-direction, and the other side in the Z-direction, with respect to the final gear shaft, or any two-way side thereof.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electric vehicle drive device. [Background technology]

[0002] In recent years, vehicles powered by internal combustion engines that are supplied with fuel from a fuel tank are being rapidly replaced by electric vehicles powered by motors that are supplied with electricity from a battery. In addition, the integration of on-board devices for driving electric vehicles is also progressing. Electric vehicle drive devices for driving electric vehicles are often configured by integrating a motor that generates power, a reduction gear that reduces the speed of the motor and transmits the power to the axles, and an inverter that converts a direct current stored in a battery into an arbitrary alternating current to efficiently drive and control the motor. Each of the motor, the reduction gear, and the inverter generates losses during energy conversion or power transmission. Heat generated by the losses increases the local temperature of each device. An excessive increase in the local temperature of each device can cause a breakdown of the electric vehicle drive device. Therefore, it is necessary to properly cool the electric vehicle drive device.

[0003] A typical cooling configuration for cooling an electric vehicle drive device is composed of an oil cooling system in which oil circulates inside the electric vehicle drive device, and an external water cooling system in which cooling water is supplied from the outside to an oil cooler, which is part of the oil cooling system (for example, Patent Document 1). In the oil cooling system, oil that is retained in the lower part of a housing that houses a reduction gear is supplied to a heat generating part via an oil cooler by an oil pump and one or more oil passages. When the heat generating part comes into contact with the oil directly or indirectly, the oil absorbs heat and cools the heat generating part, and the hot oil flows back to the lower part of the housing. The external water cooling system is composed of a radiator, a water pump, a water-cooled plate of an inverter, and an oil cooler, all connected by piping. The cooling water in the external water cooling system is circulated by the operation of a water pump.

[0004] With this configuration, cooling water is supplied from the external water-cooling system to the oil cooler, and the high-temperature oil circulating in the oil-cooling system exchanges heat with the cooling water in the oil cooler, so that the low-temperature oil can be supplied to the heat generating part. On the other hand, in the external water-cooling system, the cooling water absorbs heat from the high-temperature oil in the oil cooler, and the high-temperature cooling water dissipates heat to the surrounding air in the radiator. The low-temperature cooling water flowing out from the radiator is supplied to the oil cooler again. In the oil circulation of the oil-cooling system and the cooling water circulation of the external water-cooling system, heat is transported from the heat generating part of the electric vehicle drive device to the radiator via the oil and the cooling water, and the heat is dissipated from the radiator to the surrounding air. Note that the external water-cooling system is often provided with a fan that blows air to the radiator to cool the cooling water more efficiently, and a reservoir tank that ensures a sufficient amount of cooling water to prevent air from being mixed into the piping of the external water-cooling system.

[0005] In an electric vehicle, a battery is installed instead of a fuel tank of a conventional vehicle. In order to increase the driving range of an electric vehicle, it is desired to reduce the weight of the electric vehicle and the electric vehicle drive device, increase the battery capacity (expand the battery mounting space), and improve the energy conversion efficiency including reducing power consumption. In the structure of the above-mentioned Patent Document 1, the electric vehicle drive device can be appropriately cooled by providing an oil cooling system and an external water cooling system. However, since the electric vehicle drive device is equipped with both the oil cooling system and the external water cooling system, the electric vehicle drive device becomes larger and the weight of the electric vehicle drive device increases, which causes a problem that the electric vehicle and the electric vehicle drive device cannot be reduced in weight, and a problem that the battery mounting space cannot be expanded. In addition, since an external water cooling system is required, there is a problem that it is not easy to incorporate the electric vehicle drive device into the electric vehicle.

[0006] In order to increase the driving range of an electric vehicle, a configuration in which an electric vehicle drive device is made lighter and smaller has been disclosed (for example, Patent Documents 2, 3, and 4). Patent Document 2 discloses a configuration in which an oil pump using the rotational motion of a reducer is used to circulate oil remaining in the lower part of a housing that accommodates the reducer through the oil pump, motor, cooler, inverter (PDU), and differential mechanism in that order, and a configuration in which a fan using the rotational motion of a motor blows air to the oil cooler to efficiently cool the circulating oil. Patent Document 3 discloses a configuration of an electric vehicle drive device in which an impeller is provided on a drive shaft to which a tire is attached. This configuration air-cools the oil in the motor of the electric vehicle drive device that is provided next to the impeller without increasing costs. Patent Document 4 discloses a configuration of an electric vehicle drive device in which an opening is provided at the rear of the electric vehicle and a passage is provided that allows air to pass from the opening to the underside of the electric vehicle through the oil cooler. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 7140727 [Patent Document 2] Patent No. 4625597 [Patent Document 3] JP 2015-186343 A [Patent Document 4] Patent No. 6926984 Summary of the Invention [Problem to be solved by the invention]

[0008] In the structure of Patent Document 2, an external water cooling system is not required, so that the electric vehicle and the electric vehicle drive device can be made lighter. In addition, the rotational force of the motor is used directly or indirectly via a reduction gear as the driving force of the oil pump and the fan, so that the power consumption can be reduced. However, the maximum rotation speed of the motor used in the electric vehicle is generally 18,000 rpm or more, which is high speed. Therefore, in the structure of Patent Document 2, it is not possible to use a fan with a maximum rotation speed of up to 3,000 rpm, which is often used in consumer and general industrial applications. Since it is necessary to use a fan reinforced with high strength, the fan is expensive and large, so there is a problem that the electric vehicle drive device is not made lighter and is large. In addition, since the fan and the cooler are arranged in series in the axial direction of the motor, the volume efficiency is poor, so there is a problem that the electric vehicle drive device is large.

[0009] The above-mentioned Patent Document 3 has a structure in which an impeller is provided on the drive shaft, and therefore the oil in the motor arranged next to the impeller is air-cooled without increasing costs. However, since the impeller is configured to scoop up the wind passing under the motor, it is difficult to change the flow of the wind even if the impeller rotates in an open space, so there is a problem that the motor of the electric vehicle drive device cannot be efficiently cooled. In addition, the drive shaft is generally attached so as to extend in an oblique direction when viewed in the axial direction of the motor, and plays a role in absorbing the forward / backward or up / down movement of the tire. Therefore, the drive shaft moves significantly and the angle of the oblique direction changes, so there is a risk of contact between the electric vehicle drive device and the impeller, and even the impeller may be damaged.

[0010] In the above Patent Document 4, the oil cooler is ventilated and cooled without using a fan, so that the power consumption of the electric vehicle can be reduced. Also, as in the above Patent Document 2, an external water cooling system is not required, so that the weight of the electric vehicle and the electric vehicle drive device can be reduced. However, since the pressure difference between the opening at the rear of the electric vehicle and the underside of the electric vehicle is used as the ventilation driving force, the ventilation driving force is greatly affected by the driving state (speed, meandering, etc.) and the surrounding environment (weather, surrounding wind speed and direction, influence from surrounding vehicles (distance and relative speed), etc.). Therefore, there is a high uncertainty in the amount of air blown, and it is difficult to obtain a physically large ventilation driving force. Furthermore, high-temperature exhaust air from the electric vehicle drive device itself or from surrounding vehicles may be sucked in from the opening at the rear of the electric vehicle, so that a stable amount of air at a low temperature that can sufficiently cool the electric vehicle drive device cannot be sucked in, and therefore there is a problem that the electric vehicle drive device cannot be efficiently cooled. Furthermore, because it is necessary to blow air with low pressure loss from the rear of the electric vehicle housing the oil cooler to the underside of the electric vehicle, the ventilation passage becomes enlarged and volumetric efficiency becomes poor, resulting in a problem of the electric vehicle drive device becoming larger.

[0011] In view of the above, an object of the present disclosure is to provide an electric vehicle drive device that can be cooled efficiently, is lightweight and compact, and can be easily incorporated into an electric vehicle. [Means for solving the problem]

[0012] The electric vehicle drive device of the present disclosure includes a motor having a rotating shaft, a gearbox that houses a reduction mechanism connected to the rotating shaft and a differential mechanism connected to the reduction mechanism, a final gear shaft connected to the differential mechanism on one side, a support structure that supports the other side of the final gear shaft and is fixed to the motor, and a heat radiator that cools the electric vehicle drive device, in which the motor and the final gear shaft are disposed opposite each other with a gap between them, the direction in which the final gear shaft extends is defined as the X direction, a direction perpendicular to the X direction and in which the motor is provided relative to the final gear shaft is defined as one side in the Y direction, and a direction perpendicular to the X direction and the Y direction is defined as the Z direction, with the gearbox provided on one side of the motor and the final gear shaft in the X direction and the support structure provided on the other side of the motor and the final gear shaft in the X direction, and the heat radiator provided on one or both sides of the final gear shaft in the Y direction, one side in the Z direction, and the other side in the Z direction. Effect of the Invention

[0013] According to the electric vehicle drive device of the present disclosure, the motor and the final gear shaft are disposed facing each other with a gap therebetween, a gear box is provided on one side of the motor and the final gear shaft in the X direction, a support structure is provided on the other side of the motor and the final gear shaft in the X direction, and a radiator is provided on either one or both sides of the other side of the final gear shaft in the Y direction, one side of the Z direction, and the other side of the Z direction. Therefore, an air passage and a radiator are provided around the final gear shaft, and an external water-cooling system is not required, and heat generated inside the electric vehicle drive device can be radiated, so that the electric vehicle drive device can be efficiently cooled. Since an external water-cooling system is not required, the electric vehicle drive device can be made lighter and smaller. Since the electric vehicle drive device is made lighter and smaller, the electric vehicle can be equipped with more batteries, so that the cruising distance of the electric vehicle can be extended. In addition, since no external water-cooling system is required and the cooling mechanism formed by the ventilation passage and the heat sink is integrated into the electric vehicle drive device, the electric vehicle drive device can be easily incorporated into an electric vehicle. [Brief description of the drawings]

[0014] [Figure 1] 1 is a plan view showing an outline of an electric vehicle driving device according to a first embodiment. [Diagram 2] 1 is a front view showing an outline of an electric vehicle driving device according to a first embodiment. [Diagram 3] 1 is a side view showing an outline of an electric vehicle driving device according to a first embodiment. [Figure 4] 2 is a diagram showing a coolant flow path of the electric vehicle driving device according to the first embodiment. FIG. [Diagram 5] 5 is a diagram showing another coolant flow path of the electric vehicle driving device according to the first embodiment. FIG. [Figure 6] 5 is a diagram showing another coolant flow path of the electric vehicle driving device according to the first embodiment. FIG. [Figure 7] 5 is a diagram showing another coolant flow path of the electric vehicle driving device according to the first embodiment. FIG. [Figure 8] 5 is a diagram showing another coolant flow path of the electric vehicle driving device according to the first embodiment. FIG. [Figure 9] 1 is a cross-sectional view showing an outline of an electric vehicle driving device according to a first embodiment. [Figure 10] 11 is a front view showing an outline of an electric vehicle driving device according to a second embodiment. FIG. [Figure 11] 11 is a side view showing an outline of an electric vehicle driving device according to a second embodiment. FIG. [Figure 12] FIG. 11 is a cross-sectional view showing an outline of an electric vehicle driving device according to a third embodiment. [Figure 13] FIG. 11 is a side view showing an outline of an electric vehicle driving device according to a fourth embodiment. [Figure 14] FIG. 11 is a cross-sectional view showing an outline of an electric vehicle driving device according to a fourth embodiment. [Figure 15] FIG. 11 is a cross-sectional view showing an outline of an electric vehicle driving device according to a fourth embodiment. [Figure 16] FIG. 11 is a side view showing an outline of an electric vehicle driving device according to a fourth embodiment. [Figure 17]FIG. 11 is a cross-sectional view showing an outline of an electric vehicle driving device according to a fifth embodiment. [Figure 18] FIG. 13 is a cross-sectional view showing an outline of an electric vehicle driving device according to a sixth embodiment. [Figure 19] FIG. 13 is a cross-sectional view showing an outline of an electric vehicle driving device according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an electric vehicle drive device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the same or equivalent members and parts in each drawing will be described with the same reference numerals. Note that the electric vehicle in this disclosure is not limited to automobiles, but refers to mobility used for transportation, transport, and moving means, including motorcycles.

[0016] Embodiment 1 FIG. 1(a) is a plan view showing an outline of an electric vehicle drive device 1 according to a first embodiment, FIG. 1(b) is a plan view showing an outline of the electric vehicle drive device 1 with a heat sink 10 removed from the electric vehicle drive device 1, FIG. 2(a) is a front view showing an outline of the electric vehicle drive device 1, seen from the direction of travel of an electric vehicle 9, FIG. 2(b) is a front view showing an outline of another electric vehicle drive device 1, seen from the direction of travel of the electric vehicle 9, FIG. 3 is a side view showing an outline of the electric vehicle drive device 1, seen from the other side in the X direction, showing a schematic example of a state in which a support structure 7 has been removed from the electric vehicle drive device 1 and the electric vehicle drive device 1 is mounted on the front side of an electric vehicle 9, FIG. 4 is a diagram showing a coolant flow path 14 of the electric vehicle drive device 1 according to the first embodiment, FIGS. 5 to 8 are diagrams showing other coolant flow paths 14 of the electric vehicle drive device 1, and FIG. 9 is a cross-sectional view showing an outline of the electric vehicle drive device 1, in which the electric vehicle drive device 1 is cut along the YZ plane. The electric vehicle drive device 1 mounted on an electric vehicle 9 is a device that transmits rotation of a rotary shaft 2 a of a motor 2 to a final gear shaft 6 via a reduction mechanism 3 and a differential mechanism 4 .

[0017] <Electric vehicle drive unit 1> As shown in Fig. 2(a), the electric vehicle driving device 1 includes a motor 2 having a rotating shaft, a gearbox 5, a final gear shaft 6, a support structure 7, and a heat sink 10. The electric vehicle driving device 1 may further include an inverter 8 (not shown in Fig. 2) that is electrically connected to the motor 2 and converts electric power. The inverter 8 is fixed to the electric vehicle driving device 1, for example. The fixing point of the inverter 8 is not limited thereto, and the inverter 8 may be fixed to the electric vehicle 9 as a separate entity from the electric vehicle driving device 1.

[0018] 1(b), the motor 2 includes a stator 2d having an iron core and a coil, a rotor 2b disposed inside the stator 2d, and a housing 2c accommodating the stator 2d and the rotor 2b. A rotating shaft 2a of the rotor 2b is rotatably supported by a bearing and disposed so as to rotate coaxially with the stator 2d. The housing 2c is produced, for example, by casting or forging a metal such as aluminum.

[0019] The gear box 5 houses the reduction gear mechanism 3 connected to the rotating shaft 2a, and the differential mechanism 4 connected to the reduction gear mechanism 3. The reduction gear mechanism 3 reduces the rotation of the rotating shaft 2a of the motor 2 and outputs it. The differential mechanism 4 absorbs the speed difference between the left and right tires. The gear box 5 is produced, for example, by casting or forging a metal such as aluminum.

[0020] One side of the final gear shaft 6 is connected to the differential mechanism 4. The support structure 7 rotatably supports the other side of the final gear shaft 6 and is fixed to the motor 2. Tires (not shown) are attached to both sides of the final gear shaft 6 via drive shafts. The support structure 7 is fixed to the motor 2 by, for example, screwing. The support structure 7 is made by casting or forging a metal such as aluminum. By making the housing 2c, the gear box 5, and the support structure 7 from aluminum, they can be made lighter and less expensive, and complex shapes can be easily made. In addition, making these members from the same material provides a measure against electrolytic corrosion. The material of these members is not limited to aluminum, and may be a resin material.

[0021] The heat sink 10 cools the motor 2. The parts of the motor 2 that are cooled by the heat sink 10 are the coil of the stator 2d, the rotor 2b, the magnets, and the bearings that rotatably support the rotating shaft 2a. The parts that are cooled by the heat sink 10 are not limited to the motor 2, and may be multiple parts of the heat generating parts of the electric vehicle drive device 1. The heat generating parts of the electric vehicle drive device 1 are parts that generate heat when the electric vehicle drive device 1 is driven. For example, in the reduction mechanism 3 and the differential mechanism 4, the gear meshing parts and the bearings that rotatably support these rotating shafts (gear shafts), and in the inverter 8, the electric and electronic components (power semiconductor elements, capacitors, reactors, control boards including mounted components), wiring such as bus bars, and wiring connection parts. The details of the heat sink 10 will be described later.

[0022] <Arrangement of components of electric vehicle drive device 1> The arrangement of each member constituting the electric vehicle driving device 1 will be described. The motor 2 and the final gear shaft 6 are arranged facing each other with a gap between them. Directions are defined here. The direction in which the final gear shaft 6 extends is the X direction, the direction perpendicular to the X direction and in which the motor 2 is provided relative to the final gear shaft 6 is one side of the Y direction, and the direction perpendicular to the X direction and the Y direction is the Z direction. In each figure, the direction indicated by the arrow is one side, and the opposite direction to the direction indicated by the arrow is the other side.

[0023] The gear box 5 is provided on one side of the motor 2 and the final gear shaft 6 in the X direction, and the support structure 7 is provided on the other side of the motor 2 and the final gear shaft 6 in the X direction. The heat sink 10 is provided on one or both sides of the final gear shaft 6, the other side of the Y direction, one side of the Z direction, and the other side of the Z direction. In this embodiment, as shown in FIG. 3, the heat sink 10 is provided on one side of the final gear shaft 6 in the Z direction. The arrangement of the heat sink 10 is not limited to this, and the heat sink 10 may be provided on the other side of the Y direction or the other side of the Z direction. The number of heat sinks 10 is not limited to one, and two may be provided. When two heat sinks 10 are provided, for example, as shown in FIG. 2(b), the two heat sinks 10 are provided on two sides of the final gear shaft 6, one side of the Z direction and the other side of the Z direction. Furthermore, the heat sink 10 may be a single heat sink 10 formed in an L-shape extending on one side (or the other side) in the Z direction and on the other side in the Y direction with respect to the final gear shaft 6.

[0024] By arranging the components constituting the electric vehicle drive device 1 in this manner, the space around the final gear shaft 6 can be used as a ventilation passage that allows ventilation, and can be effectively used as an installation space for the heat sink 10. Since the ventilation passage and the heat sink 10 are provided around the final gear shaft 6, no external water-cooling system is required, and heat generated inside the electric vehicle drive device 1 can be dissipated, so the electric vehicle drive device 1 can be efficiently cooled. Since no external water-cooling system is required, the electric vehicle drive device 1 can be made lighter and smaller. Since the electric vehicle drive device 1 is made lighter and smaller, the electric vehicle 9 can be equipped with more batteries, so the cruising distance of the electric vehicle 9 can be extended. In addition, since no external water-cooling system is required and the cooling mechanism formed by the ventilation passage and the heat sink 10 is integrated into the electric vehicle drive device 1, the electric vehicle drive device 1 can be easily incorporated into the electric vehicle 9.

[0025] <Heat sink 10 and heat dissipation configuration> First, the configuration of heat dissipation by the radiator 10 will be described. In this embodiment, heat is dissipated using a coolant circulating between the radiator 10 and the heat generating parts. The coolant directly or indirectly absorbs heat from the heat generating parts of the electric vehicle drive device 1. The coolant, which has become hot by absorbing heat, passes through the radiator 10. During the passage, heat is dissipated from the coolant to the air through the solid wall of the radiator 10 by radiation and convection heat transfer to the surroundings of the radiator 10. The low-temperature coolant 11 sent out from the radiator 10 is supplied again to the heat generating parts. Through this series of actions, the heat generating parts of the electric vehicle drive device 1 can be efficiently cooled.

[0026] Next, the configuration of the heat sink 10 will be described. The heat sink 10 has a pipe through which the cooling liquid can move, and a plurality of plate-like heat sink fins that are stacked and placed with any gaps along the direction in which the pipe extends. Heat is carried throughout the pipe by the movement of the cooling liquid. Heat is transferred from the pipe wall to the heat sink fin by thermal conduction, and the heat is dissipated to the surroundings by radiation and convection heat transfer from the surface of the heat sink fin. The specific configuration of the heat sink 10 is, for example, a pipe configuration in which two headers are connected by a plurality of pipes, a series of meandering pipes, or a pipe structure in which a plurality of heat pipes are arranged in parallel, with a plurality of heat sink fins stacked and fixed in contact with the pipe. The plurality of heat pipes may be arranged with gaps between each other.

[0027] <Cooling liquid flow path 14> The configuration of the coolant flow path 14 through which the coolant 11 circulates will be described with reference to Figs. 4 to 8. In these figures, the coolant 11 circulates in the direction of the arrow. First, the coolant flow path 14 shown in Figs. 4 and 5 will be described. The radiator 10 shown in Figs. 4 and 5 is an air-cooled refrigerant cooler. The electric vehicle drive device 1 includes a coolant pump 12 and a reservoir tank 13 connected in series to the air-cooled refrigerant cooler by a pipe 14a through which the coolant 11 flows, and an inverter 8 electrically connected to the motor 2 and converting electric power. The coolant 11 is a refrigerant such as water, brine (antifreeze), or a fluorocarbon-based refrigerant. The reservoir tank 13 may be an accumulator or a receiver tank. A coolant flow path 14 is formed in which the coolant 11 contained in the reservoir tank 13 circulates through the coolant pump 12, the air-cooled refrigerant cooler, and the reservoir tank 13 in this order. The piping 14a of the coolant flow path 14 between the air-cooled refrigerant cooler and the reservoir tank 13 is provided in series so that the coolant flows through the inverter 8 and the motor 2 in order, or in parallel so that the coolant flows in parallel.

[0028] In Fig. 4, the piping 14a of the coolant flow path 14 between the air-cooled refrigerant cooler and the reservoir tank 13 is provided in series so that the coolant flows sequentially through the inverter 8 and the motor 2. In Fig. 5, the piping 14a of the coolant flow path 14 between the air-cooled refrigerant cooler and the reservoir tank 13 is provided in parallel so that the coolant flows parallelly through the inverter 8 and the motor 2. An example of cooling the reduction mechanism 3 and the differential mechanism 4 will be described. The piping 14a of the coolant flow path 14 contacts the gear box 5 that houses the reduction mechanism 3 and the differential mechanism 4, and indirectly cools the reduction mechanism 3 and the differential mechanism 4 via the lubricating oil or the structure that forms the gear box 5.

[0029] With this configuration, the inverter 8 is connected immediately after the air-cooled refrigerant cooler in the coolant flow path 14, so that the coolant 11 cooled in the air-cooled refrigerant cooler passes through the inverter 8 first, thereby most efficiently cooling the inverter 8. The inverter 8 has, for example, a water-cooled plate having a water passage therein through which the coolant 11 passes. The water-cooled plate has a cooling surface on which a group of electric and electronic devices is mounted. The group of electric and electronic devices is efficiently cooled by the coolant 11. When the coolant 11 is water, water has good thermal properties and only one heat exchange occurs, so that the inverter 8 can be cooled by the water with the lowest temperature.

[0030] Next, the coolant flow path 14 shown in FIG. 6 will be described. The radiator 10 shown in FIG. 6 is an air-cooled refrigerant cooler. The electric vehicle drive device 1 includes a coolant pump 12, a reservoir tank 13, and a refrigerant-oil heat exchanger 15 connected in series to the air-cooled refrigerant cooler by a pipe 14a through which the coolant 11 flows, and an inverter 8 electrically connected to the motor 2 and converting electric power. The coolant 11 is a refrigerant such as water, brine (antifreeze), or a fluorocarbon-based refrigerant. A coolant flow path 14 is formed in which the coolant 11 contained in the reservoir tank 13 circulates through the coolant pump 12, the air-cooled refrigerant cooler, the refrigerant-oil heat exchanger 15, and the reservoir tank 13 in this order. The portion of the pipe 14a of the coolant flow path 14 between the air-cooled refrigerant cooler and the refrigerant-oil heat exchanger 15 is provided so as to pass through the inverter 8.

[0031] The refrigerant-oil heat exchanger 15 has an oil passage that is part of an oil cooling system (not shown) in addition to a water passage that is part of the coolant flow path 14. In the refrigerant-oil heat exchanger 15, heat exchange takes place between the coolant 11 and oil, and the oil is cooled by the coolant 11. The oil cooling system is, for example, a system that circulates oil that has been cooled to a low temperature in the refrigerant-oil heat exchanger 15. The motor 2, the reduction mechanism 3, and the differential mechanism 4 are cooled as the low-temperature oil circulates through the oil cooling system.

[0032] With this configuration, the inverter 8 is connected next to the air-cooled refrigerant cooler in the cooling liquid flow path 14, and the refrigerant-oil heat exchanger 15 is connected next to the inverter 8. The cooling liquid 11 cooled in the air-cooled refrigerant cooler first cools the inverter 8, and then cools the oil in the refrigerant-oil heat exchanger 15, so that the inverter 8, the motor 2, and the gear box 5 can be cooled in a well-balanced manner. The cooled oil directly contacts the gears and bearings inside the gear box 5, and the coil ends and bearings in the motor, and can efficiently cool them. Since heat is exchanged twice, from the air to the water and from the water to the oil, the oil temperature becomes high, but since the oil is non-corrosive and lubricated, the gaps and protrusions of the gears, bearings, and coil ends can be directly cooled by the oil. Since the gaps and protrusions are directly cooled, the gears, bearings, and coil ends can be efficiently cooled.

[0033] Next, the coolant flow path 14 shown in Fig. 7 and Fig. 8 will be described. The radiator 10 shown in Fig. 7 and Fig. 8 is an air-cooled oil cooler. The electric vehicle drive device 1 includes a coolant pump 12 connected in series to the air-cooled oil cooler by a pipe 14a through which the coolant 11, which is a refrigerant, flows, and an inverter 8 electrically connected to the motor 2 and converts electric power. The coolant 11 is oil. The coolant pump 12 is provided in the gear box 5, and a coolant flow path 14 is formed in which the coolant 11 remaining at the bottom of the gear box 5 circulates through the coolant pump 12, the air-cooled oil cooler, and the gear box 5 in this order. The portion of the pipe 14a of the coolant flow path 14 between the air-cooled oil cooler and the gear box 5 is provided in series to flow through the inverter 8 and the motor 2 in order, or in parallel to flow in parallel.

[0034] In Fig. 7, the piping 14a of the coolant flow path 14 between the air-cooled oil cooler and the gear box 5 is provided in series so that the coolant flows sequentially through the inverter 8 and the motor 2. In Fig. 8, the piping 14a of the coolant flow path 14 between the air-cooled oil cooler and the gear box 5 is provided in parallel so that the coolant flows in parallel through the inverter 8 and the motor 2. Oil is supplied from the piping 14a of the coolant flow path 14 to the rotating shaft support structures and gear contact parts of the reduction gear mechanism 3 and the differential mechanism 4 in the gear box 5, and the reduction gear mechanism 3 and the differential mechanism 4 are cooled.

[0035] With this configuration, the inverter 8 and the motor 2 are connected next to the air-cooled oil cooler in the coolant flow path 14, and the gear box 5 is connected next to them. Therefore, the coolant 11 cooled in the air-cooled oil cooler first cools the gears, bearings, coil ends, etc. directly inside the motor 2 together with the inverter 8, and then cools the inside of the gear box 5, so that the motor 2 and the gear box 5 can be cooled most efficiently. The inverter 8 has, for example, an oil-cooled plate provided with an oil passage through which the coolant 11 passes. The oil-cooled plate has a cooling surface on which the electric and electronic equipment group is mounted. The electric and electronic equipment group is efficiently cooled by the coolant 11. Although the thermal properties of oil are worse than those of water, the oil has the lowest temperature because heat exchange occurs only once, and the motor 2 can be cooled efficiently.

[0036] If necessary, a strainer for collecting debris inside the coolant flow path 14, a flow divider for adjusting and switching the amount of coolant 11 distributed, and an additional flow path for lubricating the coolant to another heat generating part may be provided midway through the coolant flow path 14.

[0037] <Configuration example of electric vehicle drive device 1> A configuration example of the electric vehicle drive device 1 will be described with reference to FIG. 9. The electric vehicle drive device 1 includes a plurality of heat pipes 19 each having a heat dissipation section 16 on one side and a heat receiving section 18 on the other side, and an inverter 8 electrically connected to the motor 2 and converting electric power. The radiator 10 is the heat dissipation section 16 having a plurality of heat pipe heat dissipation fins 17. The heat receiving section 18 is thermally connected to one or both of the motor 2 and the inverter 8. In this embodiment, the heat receiving section 18 is thermally connected to both the motor 2 and the inverter 8. The radiator 10 is provided on one side in the Z direction with respect to the final gear shaft 6. The plurality of heat pipes 19 are provided side by side in the X direction, for example, with a gap therebetween. The X direction is a direction perpendicular to the paper surface.

[0038] With this configuration, since the radiator 10 is a part of the multiple heat pipes 19, no external water-cooling system is required, and heat generated inside the electric vehicle drive device 1 can be radiated, so the electric vehicle drive device 1 can be efficiently cooled. Since no external water-cooling system is required, the electric vehicle drive device 1 can be made lighter and smaller. Since the electric vehicle drive device 1 is made lighter and smaller, the electric vehicle 9 can be equipped with more batteries, so the cruising distance of the electric vehicle 9 can be extended. In addition, since no external water-cooling system is required, and the cooling mechanism formed by the ventilation passage and the radiator 10 and the inverter 8 are integrated into the electric vehicle drive device 1, the electric vehicle drive device 1 can be easily incorporated into the electric vehicle 9.

[0039] The inverter 8 is thermally connected to one side of the heat receiving portion 18 of the heat pipe 19 in the Z direction, and the motor 2 is thermally connected to the other side of the heat receiving portion 18 of the heat pipe 19 in the Z direction. The heat receiving portion 18 of the heat pipe 19 is sandwiched between the motor 2 and the inverter 8. The arrangement of the inverter 8 and the heat pipe 19 is not limited to this, and the heat pipe 19 may be provided on the other side of the Z direction with respect to the final gear shaft 6 and the motor 2. When the heat pipe 19 is provided on the other side of the Z direction with respect to the final gear shaft 6 and the motor 2, the inverter 8 is, for example, thermally connected to the other side of the heat receiving portion 18 of the heat pipe 19 in the Z direction, and the motor 2 is thermally connected to one side of the heat receiving portion 18 of the heat pipe 19 in the Z direction.

[0040] 9, a plurality of grooves that come into contact with the outer circumferential surfaces of the heat pipes 19 may be provided on the other side of the inverter 8 in the Z direction and on one side of the motor 2 in the Z direction so that the heat pipes 19 can come into contact with each other without any gaps. Alternatively, instead of providing grooves in the inverter 8 and the motor 2, a heat receiving plate that is a separate member may be provided between the inverter 8 and the heat pipes 19 and between the motor 2 and the heat pipes 19, and the outer circumferential surfaces of the heat pipes 19 may come into contact with the plurality of grooves provided in the heat receiving plate. Alternatively, a heat receiving plate having through holes may be provided with the heat pipes 19 inserted into the through holes, and the heat receiving plate with the heat pipes 19 provided therein may be sandwiched between the inverter 8 and the motor 2.

[0041] In addition to the heat pipe 19, an additional heat pipe 20 may be provided. The additional heat pipe 20 is provided in contact with the housing 2c that accommodates the motor 2. With this configuration, the heat of the motor 2 can be uniformed all around, and the heat of the motor 2 can be efficiently transferred to the heat receiving portion 18 of the heat pipe 19 that is in contact with the motor 2. Since the heat of the motor 2 is efficiently transferred, the motor 2 can be further cooled.

[0042] As shown in Fig. 9, when the center portion of the additional heat pipe 20 is disposed on the other side in the Z direction of the motor 2, the additional heat pipe 20 generates a flow of coolant on both sides in the Y direction, so that heat transport can be performed on both sides in the Y direction. Since heat transport can be performed on both sides in the Y direction, the additional heat pipe 20 can transport heat more efficiently. Note that, when the additional heat pipes 20 and the heat receiving parts 18 of the heat pipes 19 provided in the housing 2c are alternately arranged in the X direction, the height in the Z direction of the portion where the heat pipes 19 and the additional heat pipes 20 are provided in the X direction can be reduced, so that the electric vehicle drive device 1 can be made compact.

[0043] As described above, in the electric vehicle drive device 1 according to the first embodiment, the motor 2 and the final gear shaft 6 are disposed facing each other with a gap therebetween, the gear box 5 is provided on one side of the motor 2 and the final gear shaft 6 in the X direction, the support structure 7 is provided on the other side of the motor 2 and the final gear shaft 6 in the X direction, and the radiator 10 is provided on either one side of the other side of the Y direction, one side of the Z direction, or the other side of the Z direction with respect to the final gear shaft 6, or on either two sides. Therefore, a ventilation path and the radiator 10 are provided around the final gear shaft 6, and an external water-cooling system is not required, and heat generated inside the electric vehicle drive device 1 can be radiated, so that the electric vehicle drive device 1 can be efficiently cooled. Since an external water-cooling system is not required, the electric vehicle drive device 1 can be made lighter and smaller. Since the electric vehicle drive device 1 is made lighter and smaller, the electric vehicle 9 can be equipped with more batteries, so that the cruising distance of the electric vehicle 9 can be extended. In addition, since an external water-cooling system is not required and the cooling mechanism formed by the ventilation passage and the heat sink 10 is integrated into the electric vehicle drive device 1, the electric vehicle drive device 1 can be easily incorporated into the electric vehicle 9.

[0044] The radiator 10 is an air-cooled refrigerant cooler, and the electric vehicle drive device 1 includes a coolant pump 12 and a reservoir tank 13 connected in series to the air-cooled refrigerant cooler by a pipe 14a through which the coolant 11 flows, and an inverter 8. A coolant flow path 14 is formed in which the coolant 11 stored in the reservoir tank 13 circulates through the coolant pump 12, the air-cooled refrigerant cooler, and the reservoir tank 13 in that order. When the portion of the pipe 14a of the coolant flow path 14 between the air-cooled refrigerant cooler and the reservoir tank 13 is provided in series to flow through the inverter 8 and the motor 2 in order, or in parallel to flow in parallel, the inverter 8 is connected immediately after the air-cooled refrigerant cooler by the coolant flow path 14, so that the coolant 11 cooled in the air-cooled refrigerant cooler passes through the inverter 8 first, thereby cooling the inverter 8 most efficiently. In addition, when the coolant 11 is water, water has good thermal properties and only one heat exchange occurs, so that the inverter 8 can be cooled by the water with the lowest temperature.

[0045] The radiator 10 is an air-cooled refrigerant cooler, and the electric vehicle drive device 1 includes a coolant pump 12, a reservoir tank 13, and a refrigerant-oil heat exchanger 15 connected in series to the air-cooled refrigerant cooler by piping 14a through which a coolant 11 flows, and an inverter 8. A coolant flow path 14 is formed in which the coolant 11 contained in the reservoir tank 13 circulates through the coolant pump 12, the air-cooled refrigerant cooler, the refrigerant-oil heat exchanger 15, and the reservoir tank 13 in this order, and the air-cooled refrigerant cooler and the refrigerant When the portion of the pipe 14a of the coolant flow path 14 between the oil heat exchanger 15 is provided so as to pass through the inverter, the inverter 8 is connected next to the air-cooled refrigerant cooler in the coolant flow path 14, and the refrigerant-oil heat exchanger 15 is connected next to the air-cooled refrigerant cooler, so that the coolant 11 cooled in the air-cooled refrigerant cooler first cools the inverter 8 and then cools the oil in the refrigerant-oil heat exchanger 15, thereby enabling well-balanced cooling of the inverter 8, motor 2, and gear box 5. In addition, the cooled oil comes into direct contact with the gears and bearings inside the gear box 5, and the coil ends and bearings inside the motor, and can efficiently cool them.

[0046] The radiator 10 is an air-cooled oil cooler, and the electric vehicle drive device 1 includes a coolant pump 12 connected in series to the air-cooled oil cooler by a pipe 14a through which a coolant 11 flows as a refrigerant, and an inverter 8. The coolant pump 12 is provided in the gear box 5, and a coolant flow path 14 is formed in which the coolant 11 remaining at the bottom of the gear box 5 circulates through the coolant pump 12, the air-cooled oil cooler, and the gear box 5 in that order. A portion of the pipe 14a of the coolant flow path 14 between the air-cooled oil cooler and the gear box 5 is When the oil is provided in series, where the oil flows through the inverter 8 and the motor 2 in order, or in parallel, where the oil flows in parallel, the inverter 8 and the motor 2 are connected next to the air-cooled oil cooler in the coolant flow path 14, and then the gear box 5 is connected, so that the coolant 11 cooled in the air-cooled oil cooler first cools the gears, bearings, coil ends, etc. directly inside the motor 2 together with the inverter 8, and then cools the inside of the gear box 5, thereby most efficiently cooling the motor 2 and the gear box 5. Also, although the thermal properties of oil are worse than water, because heat exchange occurs only once, the oil temperature is the lowest and the motor 2 can be cooled most efficiently.

[0047] When the electric vehicle drive device 1 includes a plurality of heat pipes 19 having a heat dissipation section 16 on one side and a heat receiving section 18 on the other side, and an inverter 8, the radiator 10 is the heat dissipation section 16 having a plurality of heat pipe radiating fins 17, and the heat receiving section 18 is thermally connected to one or both of the motor 2 and the inverter 8, the radiator 10 is a part of the plurality of heat pipes 19, so that an external water cooling system is not required and heat generated inside the electric vehicle drive device 1 can be dissipated, so that the electric vehicle drive device 1 can be efficiently cooled. Since an external water cooling system is not required, the electric vehicle drive device 1 can be made lighter and smaller. Since the electric vehicle drive device 1 is made lighter and smaller, the electric vehicle 9 can be equipped with more batteries, so that the cruising distance of the electric vehicle 9 can be extended. In addition, since an external water cooling system is not required and the cooling mechanism formed by the ventilation passage and the radiator 10 and the inverter 8 are integrated into the electric vehicle drive device 1, the electric vehicle drive device 1 can be easily incorporated into the electric vehicle 9.

[0048] Embodiment 2 An electric vehicle driving device 1 according to the second embodiment will now be described. Fig. 10 is a front view showing an outline of the electric vehicle driving device 1 according to the second embodiment, as seen from the traveling direction of the electric vehicle, and Fig. 11 is a side view showing an outline of the electric vehicle driving device 1, as seen from the other side in the X direction with the support structure 7 removed from the electric vehicle driving device 1. In the electric vehicle driving device 1 according to the second embodiment, the final gear shaft 6 has an impeller 21.

[0049] The configuration of the final gear shaft 6 provided with the impeller 21 in this embodiment will be described. The final gear shaft 6 has the impeller 21 that rotates integrally with the final gear shaft 6. The drive shaft of the impeller 21 is the final gear shaft 6. As shown in FIG. 10, the final gear shaft 6 is provided between the gear box 5 and the support structure 7, as in the first embodiment, and extends in the X direction. Each end of the final gear shaft 6 is rotatably attached to the gear box 5 or the support structure 7. The motor 2 and the radiator 10 are fixed to the gear box 5 and the support structure 7, respectively. As shown in FIG. 11, the motor 2 is provided on one side of the final gear shaft 6 in the Y direction, and the radiator 10 is provided on one side of the final gear shaft 6 in the Z direction. The final gear shaft 6 is provided with an arbitrary interval from each of the radiator 10 and the motor 2, and the final gear shaft 6 has a space around it. An impeller 21 that is large enough to be accommodated in this space is fixed to the final gear shaft 6.

[0050] In this embodiment, four plate-shaped impellers 21 are fixed in contact with the final gear shaft 6. The number, shape, and arrangement of the impellers 21 are not limited to this. For example, the impellers 21 may not be directly contacted with the final gear shaft 6, but may be surrounded by an outer frame to which the impellers 21 are fixed, and the impellers 21 and the outer frame may be fixed to the final gear shaft 6 so that the impellers 21 rotate integrally with the final gear shaft 6. The final gear shaft 6 has the impellers 21 that rotate integrally with the final gear shaft 6, forming a fan 28 as shown in FIG. 10.

[0051] Each end of the final gear shaft 6 is supported by the gear box 5 or the support structure 7, and the final gear shaft 6 and the motor 2 are arranged in parallel, so that the distance between the final gear shaft 6 and the motor 2 is always constant. Therefore, when the impeller 21 is arranged next to the motor 2 while rotating, the distance in the Y direction between the end of the impeller 21 opposite to the side attached to the final gear shaft 6 and the motor 2 is always constant, so that the impeller 21 and the motor 2 do not interfere with each other. Similarly, the distance in the Z direction between the end of the impeller 21 opposite to the side attached to the final gear shaft 6 and the radiator 10 is always constant, so that the impeller 21 and the radiator 10 do not interfere with each other.

[0052] In this embodiment, the rotation of the motor 2 is transmitted to the final gear shaft 6 via the reduction mechanism 3 and the differential mechanism 4, and the impeller 21 fixed to the final gear shaft 6 rotates integrally with the final gear shaft 6. The rotation of the impeller 21 generates an airflow 21a around the final gear shaft 6. In the figure, the direction of the airflow 21a is indicated by an arrow. The airflow 21a passes through the radiator 10 arranged adjacent to the impeller 21. The airflow 21a also flows along the outer surface of the motor 2 arranged adjacent to the impeller 21. The radiator 10 and the motor 2 are forcibly air-cooled by the airflow 21a, so that the electric vehicle drive device 1 can be cooled more efficiently than in the first embodiment.

[0053] The maximum rotation speed of the motor 2 used in an electric vehicle is generally 18,000 rpm or more, and the motor 2 operates at high speed. When the impeller 21 is provided on the rotating shaft 2a of the motor 2, it is necessary to use a fan reinforced with high strength, which makes the fan expensive and large, and therefore there is a problem that the electric vehicle drive device 1 is not lightened and is large. In addition, there is a problem that the noise caused by the rotation of the impeller 21 becomes significantly large because the impeller 21 rotates at high speed. Since the reduction ratio of the reduction mechanism 3 and the differential mechanism 4, which is the rotation speed ratio between the motor 2 and the final gear shaft 6, is about 10, the rotation speed of the final gear shaft 6 is about 2,000 rpm. Since the final gear shaft 6 has the impeller 21, there is no need to particularly reinforce the impeller 21, and the noise does not become significantly large.

[0054] In addition, since the airflow 21a artificially generated by the impeller 21 is used to dissipate heat from the radiator 10 and the motor 2, the influence of the operating state (speed, meandering, etc.) and the surrounding environment (weather, surrounding wind speed and direction, influence from surrounding vehicles (distance and relative speed), etc.) is reduced. Since the influence of the operating state and the surrounding environment is reduced, a stable and sufficient amount of low-temperature air can be supplied to the radiator 10 and the motor 2.

[0055] As described above, in the electric vehicle driving device 1 according to embodiment 2, the final gear shaft 6 has the impeller 21 that rotates integrally with the final gear shaft 6. This makes it possible to effectively utilize the space around the final gear shaft 6 and supply sufficient, low-noise, and stable low-temperature air to the radiator 10 without increasing the volume of the electric vehicle driving device 1, thereby enabling the electric vehicle driving device 1 to be cooled even more efficiently.

[0056] Embodiment 3 An electric vehicle driving device 1 according to embodiment 3 will be described. Fig. 12 is a cross-sectional view showing an outline of the electric vehicle driving device 1 according to embodiment 3, cut along the YZ plane. The electric vehicle driving device 1 according to embodiment 3 has an inverter 8 provided around the final gear shaft 6.

[0057] A configuration in which an inverter 8 is provided around the final gear shaft 6 in this embodiment will be described. The electric vehicle driving device 1 includes an inverter 8 that is electrically connected to the motor 2 and converts electric power. The radiator 10 is provided on one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft 6, and the inverter 8 is provided on one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft 6, on the side where the radiator 10 is not provided. In this embodiment, the inverter 8 is provided on the other side in the Z direction with respect to the final gear shaft 6, and the radiator 10 is provided on one side in the Z direction with respect to the final gear shaft 6. The arrangement of the inverter 8 and the radiator 10 is not limited to this, and the inverter 8 may be provided on one side in the Z direction with respect to the final gear shaft 6, and the radiator 10 may be provided on the other side in the Z direction with respect to the final gear shaft 6. Moreover, either the inverter 8 or the radiator 10 may be provided on the other side in the Y direction with respect to the final gear shaft 6.

[0058] With this configuration, the air flow can be blocked on the side where the inverter 8 is provided, and the intake of air can be suppressed on the side where the radiator 10 is provided, so that the inverter 8 and the radiator 10 can be part of a ventilation path that regulates the air flow, and the remaining side where the inverter 8 and the radiator 10 are not provided can be an opening surface 22 that supplies air to the impeller 21. The opening surface 22 is an intake surface for drawing in low-temperature air around the electric vehicle drive device 1. The inverter 8, the motor 2, the gear box 5, and the support structure 7 form a ventilation path, and the air that flows in from the opening surface 22 passes through the impeller 21 and the radiator 10, so that a unidirectional airflow 21a can be formed. Since the unidirectional airflow 21a is formed, low-temperature air is stably supplied to the radiator 10, so that the electric vehicle drive device 1 can be cooled more efficiently. In the configuration shown in the second embodiment, the remaining two sides not provided with the radiator 10 contribute to both intake and exhaust, and therefore a unidirectional airflow is not formed, resulting in a configuration in which the air around the final gear shaft 6 is disturbed, and the electric vehicle driving device 1 cannot be cooled sufficiently and efficiently.

[0059] In this embodiment, the electric vehicle drive device 1 is provided with a cover 23 having a ventilation opening through which air flows in, on an opening surface 22 that is one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft 6, and is the side on which the radiator 10 and the inverter 8 are not provided. The cover 23 prevents the intrusion of flying stones that may cause damage to the impeller 21 and the radiator 10, and suppresses clogging of the radiator 10 with dirt. The cover 23 is, for example, a filter, a wire mesh, a punching metal, or a plate with an armor window. By providing the cover 23, damage to the impeller 21 and the radiator 10 due to the intrusion of flying stones is prevented, and stable air intake to the electric vehicle drive device 1 is ensured, so that the electric vehicle drive device 1 can be maintained in a good cooling state.

[0060] In this embodiment, the Z direction is the vertical direction, one side in the Z direction is the vertical upper side, and the other side in the Z direction is the vertical lower side. The inverter 8 is provided on the other side in the Z direction with respect to the final gear shaft 6, and the inverter 8 has a removable cover 24 on the other side in the Z direction. When the cover 24 is removed, the other side in the Z direction of the inverter 8 becomes a maintenance work surface for the inverter 8. If the inverter 8 is provided on one side in the Z direction with respect to the final gear shaft 6 or one side in the Z direction of the motor 2, when the inverter 8 breaks down, it is necessary to dismount the electric vehicle driving device 1 itself from the electric vehicle 9 to perform maintenance on the inverter 8. By providing the inverter 8 on the other side in the Z direction with respect to the final gear shaft 6 and having the removable cover 24 on the other side in the Z direction, the cover 24 of the inverter 8 can be removed from the vertical lower side of the electric vehicle 9 without dismounting the electric vehicle driving device 1 itself, and maintenance work on the inverter 8 can be easily performed.

[0061] In this embodiment, one or both of the motor 2 and the inverter 8 have a plurality of heat dissipation fins 25 on the side of the final gear shaft 6. In the configuration shown in FIG. 12, both the motor 2 and the inverter 8 have a plurality of heat dissipation fins 25. The plurality of heat dissipation fins 25 are formed side by side in the X direction in a ventilation passage formed by the inverter 8, the motor 2, the gear box 5, and the support structure 7. With this configuration, in addition to the heat dissipation in the radiator 10, the electric vehicle drive device 1 can also dissipate heat from the heat dissipation fins 25 by the low-temperature air that flows in from the opening surface 22 and passes through the ventilation passage. Since the electric vehicle drive device 1 also dissipates heat from the heat dissipation fins 25, the electric vehicle drive device 1 can be cooled more efficiently.

[0062] The location where the heat dissipation fins 25 are provided is not limited thereto. In this embodiment, the inverter 8 has a plurality of heat dissipation fins 25a on the lid 24, which is the portion opposite to the final gear shaft 6. The plurality of heat dissipation fins 25a are formed, for example, in a plate shape and are arranged in the X direction. With this configuration, the inverter 8 is cooled by the traveling wind passing the other side of the inverter 8 in the Z direction, so that the electric vehicle drive device 1 can be cooled more efficiently.

[0063] In this embodiment, the inverter 8 is provided on one side in the Z direction or the other side in the Z direction with respect to the final gear shaft 6, and a gap is provided between the motor 2 and the inverter 8. In the configuration shown in FIG. 12, the inverter 8 is provided on the other side in the Z direction with respect to the final gear shaft 6, and a gap 26 is provided between the motor 2 and the inverter 8. With this configuration, the air that has flowed into the ventilation passage can be discharged from the gap 26, and the air passes to the portion adjacent to the gap 26 and on the side where the heat dissipation fin 25 abuts against the motor 2 or the inverter 8, so that the electric vehicle drive device 1 can be cooled more efficiently.

[0064] As described above, in the electric vehicle drive device 1 according to the third embodiment, the radiator 10 is provided on one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft 6, and the inverter 8 is provided on one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft 6, on the side on which the radiator 10 is not provided. Therefore, a ventilation passage is formed by the inverter 8, the motor 2, the gear box 5, and the support structure 7, and the air flowing in from the opening surface 22 passes through the impeller 21 and then the radiator 10, so that a unidirectional airflow 21a can be formed. Since the unidirectional airflow 21a is formed, low-temperature air is stably supplied to the radiator 10, so that the electric vehicle drive device 1 can be cooled more efficiently.

[0065] When the inverter 8 is provided on the other side in the Z direction with respect to the final gear shaft 6, and the inverter 8 has a removable cover 24 on the other side in the Z direction, the cover 24 of the inverter 8 can be removed from the vertically lower side of the electric vehicle 9 without dismounting the electric vehicle drive device 1 itself from the electric vehicle 9, and maintenance work on the inverter 8 can be easily performed. Furthermore, when the electric vehicle drive device 1 is provided with a cover 23 having a ventilation opening through which air flows in, on an opening surface 22 that is on one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft 6 and is the side on which the radiator 10 and the inverter 8 are not provided, damage to the impeller 21 and the radiator 10 due to the intrusion of flying stones is prevented, and stable air intake to the electric vehicle drive device 1 is ensured, so that a good cooling state of the electric vehicle drive device 1 can be maintained.

[0066] When one or both of the motor 2 and the inverter 8 have a plurality of heat dissipation fins 25 on the side of the final gear shaft 6, in addition to the heat dissipation in the radiator 10, the electric vehicle drive device 1 can also dissipate heat from the heat dissipation fins 25 by the low-temperature air flowing in from the opening surface 22 and passing through the ventilation passage, so that the electric vehicle drive device 1 can be cooled more efficiently. Furthermore, when the inverter 8 is provided on one side in the Z direction or the other side in the Z direction with respect to the final gear shaft 6, and the motor 2 and the inverter 8 are provided with a gap 26 therebetween, the air that has flowed into the ventilation passage can be caused to flow out from the gap 26, so that the air passes to the part adjacent to the gap 26 and on the side of the heat dissipation fins 25 that abut against the motor 2 or the inverter 8, so that the electric vehicle drive device 1 can be cooled more efficiently. Furthermore, if the inverter 8 has a plurality of heat dissipation fins 25a on the lid 24, which is the part opposite the final gear shaft 6, the inverter 8 is cooled by the traveling wind passing through the other side of the inverter 8 in the Z direction, so that the electric vehicle driving device 1 can be cooled even more efficiently.

[0067] Embodiment 4 An electric vehicle driving device 1 according to a fourth embodiment will be described. Fig. 13 is a side view showing an outline of the electric vehicle driving device 1 according to the fourth embodiment, as viewed from the other side in the X direction, Fig. 14 is a cross-sectional view showing an outline of the electric vehicle driving device 1, as cut along the YZ plane, Fig. 15 is a cross-sectional view showing an outline of the electric vehicle driving device 1, as cut along the YZ plane, and Fig. 16 is a side view showing an outline of the electric vehicle driving device 1, as viewed from the other side in the X direction. The electric vehicle driving device 1 according to the fourth embodiment has a configuration in which an air flow path is formed around the impeller 21 by a casing 27.

[0068] The electric vehicle drive device 1 includes a casing 27 that covers the periphery of the impeller 21 and forms a flow path for air flowing in and out of the impeller 21. As described above, the inverter 8, motor 2, gearbox 5, and support structure 7 form a ventilation path, and air flowing in from opening surface 22 passes through impeller 21 and then radiator 10. By further including the casing 27 in the electric vehicle drive device 1, the flow path for air flowing in and out of the impeller 21 is further defined, improving the blowing efficiency of the fan 28 and enabling the electric vehicle drive device 1 to be cooled even more efficiently.

[0069] The type of fan 28 that rotates the impeller 21 to form an air flow path is generally classified into axial flow type, diagonal flow type, centrifugal type, and cross flow type. In each type, the flow path of the air flowing into the impeller 21 and the flow path of the air flowing out from the impeller 21 are different. Therefore, the electric vehicle drive device 1 is provided with a casing 27 suited to each type. An example configuration of an electric vehicle drive device 1 provided with a casing 27 will be described below.

[0070] The type of fan 28 shown in FIG. 13 is a centrifugal type (sirocco fan). In a centrifugal type, air flows into the impeller from one or both of the sides in the direction in which the drive shaft extends. The air that flows into the impeller flows outward in the radial direction from the fan. In the configuration shown in FIG. 13, the impeller 21 is not in direct contact with the final gear shaft 6, but an outer frame portion that surrounds the periphery of the impeller 21 and to which the impeller 21 is fixed comes into contact with the final gear shaft 6, and the impeller 21 rotates integrally with the final gear shaft 6 together with the outer frame portion.

[0071] The configuration of the casing 27 shown in FIG. 13 will be described. The electric vehicle driving device 1 includes casings 27 on both one side in the Y direction and the other side in the Y direction with respect to the final gear shaft 6. The casing 27 is provided on the other side in the Y direction with respect to the final gear shaft 6, which is the drive shaft, at an arbitrary distance from the gear box 5 side and the support structure 7 side so that an air intake port 29 for sucking air is formed on the gear box 5 side and the support structure 7 side of the final gear shaft 6, which is the drive shaft. The casing 27 has a throat 30 protruding on one side in the Y direction between the radiator 10 and the impeller 21. The throat 30 adjusts the direction of the air flow 21a. The air intake port 29 may be provided only on either one side, not on both the gear box 5 side and the support structure 7 side. The casing 27 on one side in the Y direction with respect to the final gear shaft 6 is provided along the periphery of the impeller 21 and extends toward one side of the radiator 10 in the Y direction.

[0072] By fixing the casing 27 to the electric vehicle drive device 1 in this manner, a typical centrifugal fan 28 is configured, and the airflow 21a shown in Fig. 13 is formed, thereby improving the air blowing efficiency of the fan 28. Since the air blowing efficiency of the fan 28 is improved, the electric vehicle drive device 1 can be cooled even more efficiently.

[0073] The type of the fan 28 shown in FIG. 14 is a cross-flow fan. In the cross-flow type, air flows into the impeller 21 from the radial outside of the fan 28. The air that flows into the impeller 21 flows outward in the radial direction from the fan 28. In the configuration shown in FIG. 14, the impeller 21 does not directly contact the final gear shaft 6, but an outer frame portion that surrounds the periphery of the impeller 21 and to which the impeller 21 is fixed contacts the final gear shaft 6, and the impeller 21 rotates integrally with the final gear shaft 6 together with the outer frame portion. The impeller 21 is provided in a portion between the gear box 5 and the support structure 7.

[0074] The configuration of the casing 27 shown in Fig. 14 will be described. The electric vehicle driving device 1 includes two casings 27. A casing 27 that covers the other portion between the radiator 10 and the impeller 21 in the Y direction is provided in a portion between the radiator 10 and the impeller 21. The casing 27 has a throat 30 that protrudes to one side in the Y direction on the other side in the Z direction. Another casing 27 is further provided on one side in the Y direction and on the other side in the Z direction with respect to the final gear shaft 6, around the impeller 21 and in contact with the motor 2.

[0075] By providing the casing 27 in this way, a smooth ventilation passage through which the airflow 21a passes is formed between the motor 2 and the impeller 21. In the cross-flow type, air is taken in from the circumferential portion on the other side of the impeller 21 in the Y direction with the throat 30 as a boundary, and exhausted from the circumferential portion on one side of the impeller 21 in the Y direction, so that a two-dimensional unidirectional airflow can be generated, and an efficient ventilation form can be formed with very low pressure loss. In addition, since there is no stagnation portion (accumulation portion) inside the casing 27, rainwater and dust can be easily discharged to the outside of the casing 27. In particular, even if it is difficult to discharge rainwater and dust when the electric vehicle 9 travels forward, there are cases in which the rainwater and dust can be easily discharged when the impeller 21 rotates in reverse during reverse travel. In addition, in the casing 27 in a form in which rainwater and dust accumulate inside the casing 27, it is desirable to provide an opening for discharging the rainwater and dust at the bottom of the casing 27.

[0076] The type of the fan 28 shown in FIG. 15 is a cross-flow type (cross-flow fan), and is a cross-flow type configuration different from the configuration shown in FIG. 14. The configurations in FIG. 14 and FIG. 15 are different in the position where the inverter 8 is provided. In FIG. 15, the inverter 8 is provided on the other side in the Z direction with respect to the final gear shaft 6. A ventilation path is formed by the inverter 8, the motor 2, the gear box 5, the support structure 7, and the casing 27. The portion on one side in the Z direction of the inverter 8 shown in FIG. 15 plays the role of a part of the casing 27 abutting against the motor 2 shown in FIG. 14. When the type of the fan 28 is the cross-flow type shown in FIG. 14 or FIG. 15, the throat 30 plays an important role in terms of the air blowing capacity of the fan 28.

[0077] The type of fan 28 shown in FIG. 16 is an axial flow type. In an axial flow type, air flows into the impeller from one side in the direction in which the drive shaft extends. The air that flows into the impeller flows out from the other side in the direction in which the drive shaft extends. In the configuration shown in FIG. 16, multiple impellers 21 are provided in direct contact with the final gear shaft 6, and the impellers 21 rotate integrally with the final gear shaft 6. The support structure 7 has openings around the portion that supports the final gear shaft 6. The openings are intake ports 29 for air flowing into the impellers 21.

[0078] The configuration of the casing 27 shown in Fig. 16 will be described. The electric vehicle driving device 1 includes two casings 27. The inverter 8 is provided on the other side in the Z direction with respect to the final gear shaft 6. A casing 27 is provided that covers the portion between the heat radiator 10 and the inverter 8 on the other side in the Y direction with respect to the final gear shaft 6. A casing 27 is further provided that covers the gap between the inverter 8 and the motor 2.

[0079] By providing the casing 27 in this manner, a ventilation passage is formed around the final gear shaft 6, which is a space surrounded by the casing 27, the inverter 8, and the motor 2. The air taken in from the air intake 29 is pressurized by the rotation of the impeller 21, and is sent to a portion of the ventilation passage that is a rear section of the impeller 21. A pressure difference is generated between the portion of the ventilation passage and the air around the electric vehicle drive device 1, and an airflow 21a that passes through the radiator 10 is generated using this pressure difference as a driving force, so that the radiator 10 can be cooled efficiently.

[0080] In the configuration of electric vehicle driving device 1 shown in Fig. 13, casing 27 is provided so that intake ports 29 for sucking in air are formed on the gear box 5 side of final gear shaft 6, which is the drive shaft, and on the support structure 7 side, but this is not limited to this. In the configuration of electric vehicle driving device 1 shown in Fig. 13, intake ports 29 for air flowing into impeller 21 may be provided around the portion of support structure 7 that supports final gear shaft 6, as in the configuration shown in Fig. 16.

[0081] As described above, in the electric vehicle driving device 1 according to embodiment 4, the casing 27 is provided which covers the surrounding portion of the impeller 21 and forms a flow path for air flowing in and out of the impeller 21. This further defines the flow path for air flowing in and out of the impeller 21 and improves the blowing efficiency of the fan 28, thereby enabling the electric vehicle driving device 1 to be cooled even more efficiently.

[0082] When the support structure 7 has an opening around the portion supporting the final gear shaft 6, and the opening is an intake port 29 for air flowing into the impeller 21, an axial flow fan 28 is formed, and an air flow 21a passing through the radiator 10 is generated using the pressure difference as a driving force, thereby efficiently cooling the radiator 10.

[0083] Embodiment 5. An electric vehicle driving device 1 according to embodiment 5 will be described. Fig. 17 is a cross-sectional view showing an outline of the electric vehicle driving device 1 according to embodiment 5, cut along the YZ plane. The electric vehicle driving device 1 according to embodiment 5 has a configuration in which a pipe 14a and a wiring 33 are arranged around the final gear shaft 6.

[0084] In the electric vehicle drive device 1 shown in this embodiment, the motor 2 and the inverter 8 are electrically connected by a wiring 33. One or both of the pipes 14a1 and 14a2, which are the pipes 14a, and the wiring 33 are arranged in a portion around the final gear shaft 6 between the gear box 5 and the support structure 7. The electric vehicle drive device 1 shown in FIG. 17 has the cooling flow path shown in FIG. 4. The electric vehicle drive device 1 has a pipe 14a1 that connects the radiator 10 and the inverter 8, and a pipe 14a2 that connects the inverter 8 and the motor 2. The portion around the final gear shaft 6 between the gear box 5 and the support structure 7 is a space 31, and the pipes 14a1 and 14a2 are accommodated in the space 31. In the electric vehicle drive device 1 shown in FIG. 17, the wiring 33 that connects the motor 2 and the inverter 8 is further accommodated in the space 31. The configuration is not limited to one in which both the pipe 14a and the wiring 33 are accommodated in the space 31, and one of them may be accommodated in the space 31. Furthermore, the wiring 33 housed in the space 31 is not limited to the wiring that connects the motor 2 and the inverter 8 .

[0085] In the present embodiment, the space 31 is a portion surrounded by the gear box 5, the support structure 7, the heat sink 10, the inverter 8, the motor 2, and the cover 23. The configuration of the space 31 is not limited thereto, and in a case where the electric vehicle driving device 1 further includes a casing 27, the space 31 may be a portion surrounded by the casing 27 as well.

[0086] The space 31 has a portion connected to the outside space by a gap and a ventilation opening in the cover 23. However, since the space 31 is surrounded by various members and has a structure that protects the inside, the space 31 is not in contact with external devices or people, and therefore the pipes 14a and wiring 33 housed in the space 31 are unlikely to break due to contact or the like. Therefore, by arranging the pipes 14a and wiring 33 in the space 31, the pipes 14a and wiring 33 can be protected from breakage due to contact.

[0087] Furthermore, when weak parts such as the pipes 14a and the wiring 33 are housed in the space 31, there is no risk of contact with workers, work equipment, and tools when attaching the electric vehicle drive device 1 to the electric vehicle 9, and on-board work can be easily performed. Furthermore, the pipes 14a and the wiring 33 can be reliably protected from the external environment while traveling. Furthermore, since vibrations become smaller closer to the center of the electric vehicle drive device 1, the vibration force applied to the pipes 14a and the wiring 33 in the space 31 becomes smaller, and therefore, damage to the pipes 14a and the wiring 33 due to vibration can be reduced. Furthermore, since the number of members for suppressing the vibration force can be reduced, the electric vehicle drive device 1 can be made lighter and more compact.

[0088] Embodiment 6 An electric vehicle driving device 1 according to the sixth embodiment will be described. Fig. 18 is a cross-sectional view showing an outline of the electric vehicle driving device 1 according to the sixth embodiment, cut along the YZ plane, and Fig. 19 is a cross-sectional view showing an outline of the electric vehicle driving device 1, cut along the YZ plane. In Fig. 18, one side in the Y direction is the traveling direction of the electric vehicle, and in Fig. 19, the other side in the Y direction is the traveling direction of the electric vehicle. In each drawing, there is a road surface (not shown) on the other side in the Z direction. The electric vehicle driving device 1 according to the sixth embodiment is configured to include an air guide plate 32 at the lower end on the downstream side in the traveling direction of the electric vehicle.

[0089] When the electric vehicle drive device 1 is mounted on the electric vehicle, the electric vehicle drive device 1 includes an air guide plate 32 having an inclined portion 32a on a road surface side opposite to the traveling direction of the electric vehicle, which inclines toward the road surface as the electric vehicle travels in the opposite direction to the traveling direction of the electric vehicle. With this configuration, the air flow 32b, which is the traveling wind passing through the other side of the Z direction of the electric vehicle in the downstream direction, is pushed toward the road surface, so that the rear flow of the air guide plate 32 can be made negative pressure. Since the rear flow of the air guide plate 32 is made negative pressure, the air around the electric vehicle drive device 1, particularly the air vertically above the air guide plate 32 and behind the electric vehicle drive device 1, is drawn to the rear of the air guide plate 32, so that the air can be easily discharged to the downstream side of the electric vehicle.

[0090] An example of the configuration of an electric vehicle drive device 1 provided with a baffle plate 32 will be described. In the electric vehicle drive device 1 shown in FIG. 18, the motor 2 is provided in the traveling direction of the electric vehicle, the radiator 10 is provided on one side in the Z direction with respect to the final gear shaft 6, the inverter 8 is provided on the other side in the Z direction with respect to the final gear shaft 6, and the other side in the Y direction with respect to the final gear shaft 6 is open. The baffle plate 32 is provided on the other side in the Z direction of the inverter 8 and on the other side in the Y direction. The electric vehicle drive device 1 includes a casing 27 on the other side in the Y direction of the portion between the impeller 21 and the radiator 10. The type of the fan 28 is a cross-flow type.

[0091] With this configuration, the air flow can be blocked on the side where the inverter 8 is provided, and the side where the radiator 10 is provided can be used as the air intake side. Air is exhausted from the opening on the other side in the Y direction with respect to the final gear shaft 6. A ventilation path is formed by the inverter 8, the motor 2, the gear box 5, and the support structure 7, and a unidirectional airflow 21a can be formed. Because the unidirectional airflow 21a is formed, low-temperature air is stably supplied to the radiator 10, and the electric vehicle drive device 1 can be cooled even more efficiently.

[0092] In the electric vehicle driving device 1 shown in FIG. 19, the motor 2 is provided on the opposite side to the traveling direction of the electric vehicle, the radiator 10 is provided on one side in the Z direction relative to the final gear shaft 6, the inverter 8 is provided on the other side in the Z direction relative to the final gear shaft 6, and the other side in the Y direction relative to the final gear shaft 6 is the opening surface 22. The air guide plate 32 is provided on the other side in the Z direction of the motor 2 and on one side in the Y direction. Other configurations of the electric vehicle driving device 1 in FIG. 19 are similar to those of the electric vehicle driving device 1 shown in FIG. 15.

[0093] The direction of the airflow 21a passing through the radiator 10 is different between the electric vehicle driving device 1 in Fig. 18 and the electric vehicle driving device 1 in Fig. 19, but the direction of the airflow 21a may be either as long as a unidirectional airflow 21a is formed. Also, the side on which the opening is provided in the ventilation passage may be the side in the traveling direction of the electric vehicle or the side opposite the traveling direction. Also, the mounting position of the electric vehicle driving device 1 may be the front side or the rear side of the electric vehicle.

[0094] Additionally, while the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not exemplified are assumed within the scope of the technology disclosed in the present specification, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment.

[0095] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) A motor having a rotating shaft; a gear box that accommodates a reduction mechanism connected to the rotating shaft and a differential mechanism connected to the reduction mechanism; a final gear shaft, one side of which is connected to the differential mechanism; a support structure supporting the other side of the final gear shaft and fixed to the motor; a heat sink for cooling the motor, The motor and the final gear shaft are disposed opposite to each other with a gap therebetween, a direction in which the final gear shaft extends is defined as an X direction, a direction perpendicular to the X direction and in which the motor is provided with respect to the final gear shaft is defined as one side of a Y direction, and a direction perpendicular to the X direction and the Y direction is defined as a Z direction, the gear box is provided on one side of the motor and the final gear shaft in the X direction, and the support structure is provided on the other side of the motor and the final gear shaft in the X direction; An electric vehicle drive device in which the heat radiator is provided on one or both of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft. (Appendix 2) The radiator is an air-cooled refrigerant cooler, a coolant pump and a reservoir tank connected in series to the air-cooled refrigerant cooler by a pipe through which a coolant flows; an inverter electrically connected to the motor and configured to convert electric power; A coolant flow path is formed so that the coolant contained in the reservoir tank circulates through the coolant pump, the air-cooled refrigerant cooler, and the reservoir tank in this order; 2. The electric vehicle drive device according to claim 1, wherein the piping portion of the coolant flow path between the air-cooled refrigerant cooler and the reservoir tank is provided in series to flow sequentially through the inverter and the motor, or in parallel to flow in parallel through the inverter and the motor. (Appendix 3) The radiator is an air-cooled refrigerant cooler, A coolant pump, a reservoir tank, and a coolant-oil heat exchanger connected in series to the air-cooled refrigerant cooler by piping through which a coolant, which is a refrigerant, flows; an inverter electrically connected to the motor and configured to convert electric power; A coolant flow path is formed through which the coolant contained in the reservoir tank circulates through the coolant pump, the air-cooled refrigerant cooler, the refrigerant-oil heat exchanger, and the reservoir tank in this order; 2. The electric vehicle drive device according to claim 1, wherein the portion of the piping of the coolant flow path between the air-cooled refrigerant cooler and the refrigerant-oil heat exchanger is arranged to pass through the inverter. (Appendix 4) The radiator is an air-cooled oil cooler, a coolant pump connected in series to the air-cooled oil cooler by a pipe through which a coolant flows; an inverter electrically connected to the motor and configured to convert electric power; The coolant pump is provided in the gear box, A cooling liquid flow path is formed in which the cooling liquid remaining at the bottom of the gear box circulates through the cooling liquid pump, the air-cooled oil cooler, and the gear box in this order; 2. The electric vehicle drive device according to claim 1, wherein the piping portion of the coolant flow path between the air-cooled oil cooler and the gearbox is provided in series so as to flow sequentially through the inverter and the motor, or in parallel so as to flow in parallel. (Appendix 5) A plurality of heat pipes each having a heat dissipation portion on one side and a heat receiving portion on the other side; an inverter electrically connected to the motor and configured to convert electric power; the heat sink is a heat dissipation unit having a plurality of heat pipe heat dissipation fins, 2. The electric vehicle driving device according to claim 1, wherein the heat receiving portion is thermally connected to one or both of the motor and the inverter. (Appendix 6) 6. The electric vehicle driving device according to any one of claims 1 to 5, wherein the final gear shaft has an impeller that rotates integrally with the final gear shaft. (Appendix 7) an inverter electrically connected to the motor for converting electric power; The heat radiator is provided on one of the other side in the Y direction, the one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft, An electric vehicle drive device according to any one of claims 1 to 6, wherein the inverter is provided on one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft, on a side on which the radiator is not provided. (Appendix 8) The Z direction is a vertical direction, one side of the Z direction is a vertical upper side, and the other side of the Z direction is a vertical lower side, The inverter is provided on the other side in the Z direction with respect to the final gear shaft, 8. The electric vehicle driving device according to claim 7, wherein the inverter has a removable cover on the other side in the Z direction. (Appendix 9) 9. The electric vehicle drive device according to claim 7 or 8, further comprising a cover having a ventilation opening through which air flows in, on one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft, where the radiator and the inverter are not provided. (Appendix 10) The electric vehicle drive device according to any one of appendixes 7 to 9, wherein one or both of the motor and the inverter have a plurality of heat dissipation fins on a portion on the side of the final gear shaft. (Appendix 11) The inverter is provided on one side in the Z direction or the other side in the Z direction with respect to the final gear shaft, 11. The electric vehicle driving device according to claim 10, wherein the motor and the inverter are provided with a gap therebetween. (Appendix 12) 12. The electric vehicle driving device according to any one of claims 7 to 11, wherein the inverter has a plurality of heat dissipation fins on a portion opposite to the final gear shaft. (Appendix 13) 7. The electric vehicle drive device according to claim 6, further comprising a casing that covers a periphery of the impeller and forms a flow path for air flowing in and out of the impeller. (Appendix 14) the support structure has an opening around a portion that supports the final gear shaft, 14. The electric vehicle drive device according to claim 13, wherein the opening is an intake port for air flowing into the impeller. (Appendix 15) The motor and the inverter are electrically connected by wiring, 5. The electric vehicle drive device according to any one of claims 2 to 4, wherein one or both of the piping and the wiring are arranged in a portion around the final gear shaft between the gearbox and the support structure. (Appendix 16) 16. The electric vehicle drive device according to any one of appendixes 1 to 15, further comprising an air guide plate having an inclined portion that approaches the road surface as the electric vehicle travels in the opposite direction to the traveling direction, when the electric vehicle drive device is mounted on the electric vehicle. [Explanation of symbols]

[0096] 1 electric vehicle drive device, 2 motor, 2a rotating shaft, 2b rotor, 2c housing, 2d stator, 3 reduction mechanism, 4 differential mechanism, 5 gearbox, 6 final gear shaft, 7 support structure, 8 inverter, 9 electric vehicle, 10 radiator, 11 coolant, 12 coolant pump, 13 reservoir tank, 14 coolant flow path, 14a, 14a1, 14a2 piping, 15 refrigerant-oil heat exchanger, 16 heat dissipation section, 17 heat pipe heat dissipation fin, 18 heat receiving section, 19 heat pipe, 20 additional heat pipe, 21 impeller, 21a air flow, 22 opening surface, 23 cover, 24 lid, 25, 25a heat dissipation fin, 26 gap, 27 casing, 28 fan, 29 intake port, 30 throat, 31 space, 32 Air guide plate, 32a inclined portion, 32b air flow, 33 wiring

Claims

1. A motor having a rotating shaft; a gear box that accommodates a reduction mechanism connected to the rotating shaft and a differential mechanism connected to the reduction mechanism; a final gear shaft, one side of which is connected to the differential mechanism; a support structure supporting the other side of the final gear shaft and fixed to the motor; a heat sink for cooling the motor, The motor and the final gear shaft are disposed opposite to each other with a gap therebetween, a direction in which the final gear shaft extends is defined as an X direction, a direction perpendicular to the X direction and in which the motor is provided with respect to the final gear shaft is defined as one side of a Y direction, and a direction perpendicular to the X direction and the Y direction is defined as a Z direction, the gear box is provided on one side of the motor and the final gear shaft in the X direction, and the support structure is provided on the other side of the motor and the final gear shaft in the X direction; An electric vehicle drive device in which the heat radiator is provided on one or two of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft.

2. The radiator is an air-cooled refrigerant cooler, A coolant pump and a reservoir tank connected in series to the air-cooled refrigerant cooler by a pipe through which a coolant flows; an inverter electrically connected to the motor and configured to convert electric power; A coolant flow path is formed so that the coolant contained in the reservoir tank circulates through the coolant pump, the air-cooled refrigerant cooler, and the reservoir tank in this order; 2. The electric vehicle drive device according to claim 1, wherein the piping portion of the coolant flow path between the air-cooled refrigerant cooler and the reservoir tank is provided in series so as to flow sequentially through the inverter and the motor, or in parallel so as to flow in parallel.

3. The radiator is an air-cooled refrigerant cooler, A coolant pump, a reservoir tank, and a coolant-oil heat exchanger connected in series to the air-cooled refrigerant cooler by piping through which a coolant, which is a refrigerant, flows; an inverter electrically connected to the motor and configured to convert electric power; A coolant flow path is formed through which the coolant contained in the reservoir tank circulates through the coolant pump, the air-cooled refrigerant cooler, the refrigerant-oil heat exchanger, and the reservoir tank in this order; 2. The electric vehicle drive device according to claim 1, wherein the portion of the piping of the coolant flow path between the air-cooled refrigerant cooler and the refrigerant-oil heat exchanger is provided so as to pass through the inverter.

4. The radiator is an air-cooled oil cooler, a coolant pump connected in series to the air-cooled oil cooler by a pipe through which a coolant flows; an inverter electrically connected to the motor and configured to convert electric power; The coolant pump is provided in the gear box, A cooling liquid flow path is formed in which the cooling liquid remaining at the bottom of the gear box circulates through the cooling liquid pump, the air-cooled oil cooler, and the gear box in this order; 2. The electric vehicle drive device according to claim 1, wherein the piping portion of the coolant flow path between the air-cooled oil cooler and the gearbox is provided in series so as to flow sequentially through the inverter and the motor, or in parallel so as to flow in parallel through the inverter and the motor.

5. A plurality of heat pipes each having a heat dissipation portion on one side and a heat receiving portion on the other side; an inverter electrically connected to the motor and configured to convert electric power; the heat sink is a heat dissipation unit having a plurality of heat pipe heat dissipation fins, The electric vehicle driving device according to claim 1 , wherein the heat receiving portion is thermally connected to one or both of the motor and the inverter.

6. The electric vehicle drive device according to claim 1 , wherein the final gear shaft has an impeller that rotates integrally with the final gear shaft.

7. an inverter electrically connected to the motor for converting electric power; the heat radiator is provided on one of the other side in the Y direction, the one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft, 7. The electric vehicle drive device according to claim 1, wherein the inverter is provided on one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft, on a side on which the heat radiator is not provided.

8. The Z direction is a vertical direction, one side of the Z direction is a vertical upper side, and the other side of the Z direction is a vertical lower side, The inverter is provided on the other side in the Z direction with respect to the final gear shaft, The electric vehicle drive device according to claim 7 , wherein the inverter has a detachable cover on the other side in the Z direction.

9. 8. The electric vehicle drive device according to claim 7, further comprising a cover having a ventilation opening through which air flows in, on one of the other side in the Y direction, one side in the Z direction, and the other side in the Z direction with respect to the final gear shaft, where the radiator and the inverter are not provided.

10. The electric vehicle drive device according to claim 7 , wherein one or both of the motor and the inverter have a plurality of heat dissipation fins on a portion on the side of the final gear shaft.

11. The inverter is provided on one side in the Z direction or the other side in the Z direction with respect to the final gear shaft, The electric vehicle driving device according to claim 10 , wherein the motor and the inverter are provided with a gap therebetween.

12. The electric vehicle drive device according to claim 7 , wherein the inverter has a plurality of heat dissipation fins on a portion opposite to the final gear shaft.

13. The electric vehicle drive device according to claim 6 , further comprising a casing that covers a peripheral portion of the impeller and defines a flow path for air flowing in and out of the impeller.

14. the support structure has an opening around a portion that supports the final gear shaft, The electric vehicle drive device according to claim 13 , wherein the opening is an intake port for air flowing into the impeller.

15. The motor and the inverter are electrically connected by wiring, 5. The electric vehicle drive device according to claim 2, wherein one or both of the piping and the wiring are arranged in a portion around the final gear shaft between the gearbox and the support structure.

16. 2. The electric vehicle drive device according to claim 1, further comprising an air guide plate having an inclined portion that approaches the road surface as the electric vehicle travels in the opposite direction to the traveling direction, when the electric vehicle drive device is mounted on the electric vehicle.

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