Electric drive device for vehicle

Abstract

In an electric drive device for a vehicle having a rear wheel drive mode and a four-wheel drive mode, the rear wheel side of a four-wheel drive vehicle is provided with: a rear wheel drive device including a permanent magnet motor that is powered by a battery, is driven, and transmits a drive rotational force to the rear wheels, and a first power transmission mechanism; and a power conversion module in which a first inverter for operating the rear wheel drive device and a power supply unit connected to the battery and performing power conversion are integrated, the front wheel side of the four-wheel drive vehicle being provided with: a front wheel drive device including a winding excitation motor for transmitting drive rotational force to the front wheels and a second power transmission mechanism; and a heat exchange system having a heat transfer mechanism for using waste heat from the front wheel drive device and the second inverter in the air conditioning device, the rear wheel drive device being integrated with the power conversion module.

Description

Technical Field

[0001] The present disclosure relates to an electric drive device for a vehicle. Background Art

[0002] In recent years, vehicles equipped with electric motors as a driving force, such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs), have become increasingly common. These vehicles (hereinafter collectively referred to as "electric vehicles") are equipped with heat exchange systems for heating and cooling the motors and other components.

[0003] Patent Document 1 discloses a four-wheel drive electric vehicle with a drive unit and an inverter module mounted on the front and rear wheels, respectively. In a four-wheel drive electric vehicle, a battery is mounted in the center of the vehicle, which supplies power to the inverter modules for the front and rear wheels, respectively, to operate the drive unit, thereby driving the front and rear wheel drive motors.

[0004] Patent Document 1: U.S. Patent Application Publication No. 2022 / 0348091

[0005] Patent Document 1 discloses the structure of a four-wheel drive electric vehicle, but does not disclose any information regarding the heat exchange system used to preheat and cool the drive unit, battery, and other components that serve as the electric vehicle's power source. Furthermore, in four-wheel drive electric vehicles, the front and rear wheels are rotated by separate motors. However, particularly in high-output electric vehicles, the rear wheel motor, which provides traction during acceleration, is often the main motor, while the front wheel motor is often the auxiliary motor. In such situations, considering the ease of power supply to the motor and battery charging, the power conversion module, including the inverter and onboard charger, must be optimally positioned. However, Patent Document 1 does not disclose any information regarding the placement of the power conversion module. Furthermore, in electric vehicles, it is also necessary to suppress the deterioration in power and fuel consumption (hereinafter referred to as "power consumption, etc.") caused by heating during winter, but Patent Document 1 also does not disclose any information regarding this aspect. Summary of the Invention

[0006] Therefore, in a four-wheel drive vehicle in which the front and rear wheels are rotated by respective drive motors, a vehicle electric drive device that is configured in a manner suitable for high output and can achieve improvements in power consumption and the like is desired.

[0007] The characteristic structure of the electric drive device for a vehicle disclosed herein is as follows. A vehicle electric drive device includes, on the rear wheel side of a four-wheel drive vehicle having a rear-wheel drive mode and a four-wheel drive mode, a rear-wheel drive device comprising a permanent magnet motor powered and driven by a battery and transmitting drive rotational force to the rear wheels, and a first power transmission mechanism; and a power conversion module integrating a first inverter that operates the rear-wheel drive device and a power supply unit connected to the battery and performing power conversion. On the front wheel side of the four-wheel drive vehicle, a front-wheel drive device comprising a winding-excited motor that transmits drive rotational force to the front wheels, and a second power transmission mechanism; and a heat exchange system comprising a heat transfer mechanism for utilizing waste heat from the front-wheel drive device and the second inverter for an air conditioning device. The rear-wheel drive device is integrated with the power conversion module.

[0008] In high-output four-wheel-drive vehicles, traction is applied to the rear wheels during acceleration. Therefore, in this configuration, smooth acceleration can be achieved by using a permanent magnet motor in the rear-wheel drive unit, which is advantageous at low speeds and low rotations. Furthermore, in this configuration, the rear-wheel drive unit and the power conversion module are located on the rear wheel side of the four-wheel-drive vehicle. This allows for centralized placement of the high-voltage wiring and cooling water wiring required for the rear-wheel drive unit and the power conversion module, respectively, and minimizes the layout of the wiring and piping. This reduces the space occupied by the electric drive unit in the four-wheel-drive vehicle.

[0009] In this configuration, a coil-excited motor is used as the drive motor for the front-wheel drive system. When using a coil-excited motor, the field coil and armature coil are energized without generating a rotating magnetic field, allowing the coil-excited motor to generate heat without rotating. This allows the cooling water used to cool the coil-excited motor to be heated and used to heat the vehicle cabin even when the four-wheel drive vehicle is parked.

[0010] Typically, the cabin air conditioning system is located at the front of the vehicle. Therefore, by placing the heat exchange system on the front wheel side of a four-wheel drive vehicle, as in this configuration, the length of the piping used to circulate cooling water and refrigerant from the heat exchange system to the air conditioning system can be shortened. This allows the cooling water heated by the heat generated by the front-wheel drive system to be used for heating, rather than being cooled. This improves heat utilization efficiency and reduces power consumption.

[0011] Furthermore, integrating the rear-wheel drive system with the power conversion module reduces the overall volume and improves space efficiency compared to separate configurations. Furthermore, high-voltage wiring and cooling water wiring used by the rear-wheel drive system and the power conversion module can be shared.

[0012] As described above, in a four-wheel drive vehicle in which the front and rear wheels are rotated by respective drive motors, it is possible to provide a vehicle electric drive device that is configured in a manner suitable for high output and that can achieve improvements in power consumption and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 1 is a diagram showing a schematic configuration of a vehicle electric drive device according to the present embodiment.

[0014] Figure 2 It is a perspective view showing the rear-wheel drive device and the power conversion module.

[0015] Figure 3 It is a perspective view showing a front-wheel drive device.

[0016] Figure 4 It is a diagram showing the structure of a heat exchange system.

[0017] Figure 5 It is a perspective view showing a heat exchange module. DETAILED DESCRIPTION

[0018] The following describes in detail embodiments of the electric drive device for a vehicle according to the present disclosure, based on the accompanying drawings. The embodiments described below are merely illustrative examples of the present disclosure and are not limited to these embodiments. Therefore, the present disclosure may be implemented in various ways without departing from its scope.

[0019] [Overall structure]

[0020] Figure 1 The structure of a four-wheel drive vehicle 1 equipped with a vehicle electric drive device 2 according to this embodiment is shown. The four-wheel drive vehicle 1 is an automobile that generates driving force for both the rear wheels 3 and the front wheels 4. The four-wheel drive vehicle 1 according to this embodiment is an electric vehicle (such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a battery electric vehicle (BEV), or a fuel cell electric vehicle (FCEV)) equipped with wheel drive motors as a driving source for travel. The vehicle electric drive device 2 is configured to include a rear-wheel drive device 10, a power conversion module 20, a front-wheel drive device 30, and a heat exchange system 40. The four-wheel drive vehicle 1 according to this embodiment has a rear-wheel drive mode in which the rear wheels 3 are driven by the rear-wheel drive device 10, and a four-wheel drive mode in which the front-wheel drive device 30 and the rear-wheel drive device 10 drive the front wheels 4 and the rear wheels 3. In this case, the rear-wheel drive device 10 serves as the main engine, and the front-wheel drive device 30 serves as the auxiliary engine.

[0021] [Structure of the rear-wheel drive system and power conversion module]

[0022] like Figure 2 As shown, the rear-wheel drive device 10 and the power conversion module 20 are housed together in a housing 13, forming an integrated structure. The rear-wheel drive device 10 includes a permanent magnet motor 11 and a first power transmission mechanism 12. The permanent magnet motor 11 is a well-known motor that generates excitation using permanent magnets, and therefore a detailed description thereof is omitted. The power conversion module 20 includes a first inverter 21 and a power supply unit 22. The rear-wheel drive device 10 and the power conversion module 20 are arranged near the rear wheels 3 (at the rear side of the four-wheel drive vehicle 1).

[0023] The housing 13 has a first space 13a, a second space 13b, and a third space 13c. The second and third spaces 13b and 13c are located laterally relative to the first space 13a. The first space 13a houses the power conversion module 20, the second space 13b houses the permanent magnet motor 11 of the rear-wheel drive system 10, and the third space 13c houses the first power transmission mechanism 12.

[0024] The first inverter 21 of the power conversion module 20, housed in the first space 13a, includes a motor drive substrate 21a mounted with a switching element 21b. The switching element 21b controls the drive current for the permanent magnet motor 11. Power is supplied to the power conversion module 20 from the battery 6. In other words, the permanent magnet motor 11 is driven by the power supplied by the battery 6. The structure of the first inverter 21 is well known, and therefore a detailed description thereof will be omitted.

[0025] The power supply unit 22 of the power conversion module 20 is connected to the battery 6 and performs power conversion. The battery 6 is a high-voltage battery that drives the permanent magnet motor 11. The power supply unit 22 includes an OBC (On Board Charger) substrate 22a on which a power converter 22b is mounted. The power converter 22b includes at least an AC-DC converter that converts externally input alternating current into direct current, and a DC-DC converter that converts direct current voltage into a DC voltage suitable for charging the battery 6. The structures of the AC-DC converter and the DC-DC converter are well known, so a detailed description will be omitted.

[0026] The first inverter 21 and the power supply unit 22 are integrated within the first space 13a of the housing 13. The term "integrated" not only includes a configuration in which the first inverter 21 and the power supply unit 22 are arranged in the same housing 13, but also includes a configuration in which the housings of the first inverter 21 and the power supply unit 22 are separate and fixed to each other to form an integrated structure.

[0027] The power conversion module 20 includes a control board 23 that controls the first inverter 21 and the power supply unit 22. The motor drive board 21a, the OBC board 22a, and the control board 23 are separate boards, and the motor drive board 21a and the control board 23, as well as the OBC board 22a and the control board 23, are connected via connectors 23a. In addition to the above, the power conversion module 20 includes a film capacitor 24, which is used for both smoothing the first inverter 21 and smoothing the secondary side of the DC-DC converter of the power converter 22b; and a cooling plate 25, which allows cooling water to flow through the internal space. The housing 13 has an opening at the top of the first space 13a, and the power conversion module 20 is housed within the first space 13a through this opening. The opening is closed by a cover 27, making the first space 13a a sealed space. The cooling water in this embodiment refers to, for example, antifreeze liquid primarily containing ethylene glycol or extended life coolant (LLC), etc.

[0028] The second space 13b houses the permanent magnet motor 11 of the rear-wheel drive system 10, driven by the first inverter 21 of the power conversion module 20. The third space 13c houses the first power transmission mechanism 12, which reduces and outputs the rotation of the permanent magnet motor 11. Within the housing 13, the second space 13b houses the permanent magnet motor 11 from the side and is enclosed by a motor cover 11b secured by bolts (not shown). The motor shaft 11a extends from the permanent magnet motor 11 to both sides along the rotation axis. One motor shaft 11a passes through the motor cover 11b and is exposed outside the housing 13. The other motor shaft 11a passes through the third space 13c.

[0029] The third space 13c accommodates the first power transmission mechanism 12 from the side, and is closed by the gear cover 12b fastened by bolts not shown in the figure to form a closed space. Another motor shaft 11a extending from the second space 13b is connected to the first power transmission mechanism 12, and the rotation of the permanent magnet motor 11 is input through the motor shaft 11a. The first power transmission mechanism 12 reduces the speed of the rotation of the permanent magnet motor 11 and outputs it from the gear shaft 12a. The gear shaft 12a passes through the gear cover 12b and is exposed to the outside of the housing 13. The driving force of the permanent magnet motor 11 output from the gear shaft 12a is transmitted to the axle 3a and drives the rear wheel 3 (refer to Figure 1 ).

[0030] [Structure of the front-wheel drive system]

[0031] like Figure 3 As shown, the front wheel drive device 30 is housed in a housing 39. The front wheel drive device 30 includes a coil excitation motor 31 and a second power transmission mechanism 32. The coil excitation motor 31 is a well-known motor that generates excitation through an excitation coil, so detailed description thereof is omitted. The front wheel drive device 30 is arranged near the front wheel 4 (on the front side of the four-wheel drive vehicle 1) (see Figure 1 ).

[0032] The housing 39 has a first space 39a, a second space 39b, and a third space 39c. The second and third spaces 39b and 39c are located below the first space 39a. The first space 39a houses the second inverter 33 and the power converter 34, the second space 39b houses the coil-excited motor 31 of the front-wheel drive system 30, and the third space 39c houses the second power transmission mechanism 32.

[0033] The second inverter 33 accommodated in the first space 39a includes an armature coil drive substrate 33a on which a switching element 33b is mounted. The switching element 33b controls the drive current of the armature coil of the drive winding excitation motor 31. The structure of the second inverter 33 is well known, and therefore a detailed description thereof is omitted.

[0034] The power converter 34, housed in the first space 39a, includes an excitation coil drive substrate 34a on which is mounted a power converter 34b. This power converter 34b controls the drive current for the excitation coils of the winding excitation motor 31. The power converter 34b includes a DC-DC converter that converts the DC voltage of the battery 6 into a DC voltage suitable for supplying power to the excitation coils of the winding excitation motor 31. The structure of the DC-DC converter is well known, and therefore a detailed description thereof will be omitted.

[0035] The front-wheel drive system 30 includes a control board 35 that controls the second inverter 33 and the power converter 34. The armature coil drive board 33a, the field coil drive board 34a, and the control board 35 are separate boards, and the armature coil drive board 33a and the control board 35, as well as the field coil drive board 34a and the control board 35, are connected via connectors 35a. In addition to the above, the front-wheel drive system 30 includes a film capacitor 36, which is used for both smoothing the second inverter 33 and smoothing the secondary side of the DC-DC converter of the power converter 34, and a cooling plate 37 for circulating cooling water within the internal space. The housing 39 has an opening at the top of the first space 39a, through which the second inverter 33 and the power converter 34 are housed. The opening is closed by a cover 38, making the first space 39a a sealed space.

[0036] The second space 39b houses the coil-excitation motor 31 of the front-wheel drive system 30, which is driven by the second inverter 33 and power converter 34. The third space 39c houses the second power transmission mechanism 32, which reduces the speed of the rotation of the coil-excitation motor 31 and outputs the power. Within the housing 39, the second space 39b houses the coil-excitation motor 31 from the side and is enclosed by a motor cover 31b secured with bolts (not shown). Motor shafts 31a extend from the coil-excitation motor 31 to either side along the rotation axis. One motor shaft 31a passes through the motor cover 31b and is exposed outside the housing 39. The other motor shaft 31a passes through the third space 39c.

[0037] The third space 39c accommodates the second power transmission mechanism 32 from the side, and is closed by the gear cover 32b fastened by bolts not shown in the figure to form a closed space. Another motor shaft 31a extending from the second space 39b is connected to the second power transmission mechanism 32, and the rotation of the winding excitation motor 31 is input through the motor shaft 31a. The second power transmission mechanism 32 reduces the rotation of the winding excitation motor 31 and outputs it from the gear shaft 32a. The gear shaft 32a passes through the gear cover 32b and is exposed to the outside of the housing 39. The driving force of the winding excitation motor 31 output from the gear shaft 32a is transmitted to the axle 4a and drives the front wheel 4 (refer to Figure 1 ).

[0038] [Structure of heat exchange system]

[0039] like Figure 1 As shown, the heat exchange system 40 is arranged on the front wheel 4 side of the four-wheel drive vehicle 1. Figure 4 As shown, the heat exchange system 40 includes a cooling water circuit 41 through which cooling water flows, and a refrigerant circuit 42 through which refrigerant flows. The cooling water circuit 41 includes a radiator 43, a water-cooled capacitor 44 (an example of a condenser), a heater core 45, a cooler 46 (an example of an evaporator), and an electric pump 47. The refrigerant circuit 42 includes a water-cooled capacitor 44, a cooler 46, an indoor capacitor 48, an evaporator 49, a accumulator 50, and a compressor 51. Heat is exchanged between the cooling water and the refrigerant in the water-cooled capacitor 44 and the cooler 46. The refrigerant may be, for example, a hydrofluorocarbon (HFC) or a hydrofluoroolefin (HFO).

[0040] The cooling water circuit 41 includes a looped first cooling water flow path 41a (an example of a cooling water flow path) that sequentially circulates cooling water through the radiator 43, the water-cooled capacitor 44, the heater core 45, and the cooler 46. Cooling water cooled by the radiator 43 flows through the first cooling water flow path 41a and flows into the water-cooled capacitor 44. The cooling water flowing into the water-cooled capacitor 44 removes heat from the refrigerant and is heated. The cooling water flowing out of the water-cooled capacitor 44 is further heated by the heater core 45 and flows into the cooler 46. The cooling water flowing into the cooler 46 removes heat from the refrigerant and is cooled. The cooling water flowing out of the cooler 46 flows back to the radiator 43 and is cooled by the radiator 43.

[0041] The cooling water circuit 41 further includes a second cooling water flow path 41b (an example of a cooling water flow path) that branches from the first cooling water flow path 41a and merges with the first cooling water flow path 41a. The second cooling water flow path 41b branches from the middle of the first cooling water flow path 41a, connecting the cooler 46 and the radiator 43. The second cooling water flow path 41b branching from the first cooling water flow path 41a is pumped by an electric pump 47.

[0042] like Figure 1 As shown, cooling water pumped by the electric pump 47 and flowing out of the heat exchange system 40 flows into the water heater 52. The water heater 52 heats the cooling water as needed, such as in extremely low temperatures, and branches the second cooling water flow path 41b into two. One of the branched second cooling water flow paths 41b extends toward the rear of the four-wheel drive vehicle 1 and is connected to the power conversion module 20 and the rear-wheel drive system 10. In other words, the cooling water flowing out of the water heater 52 flows toward the rear of the vehicle and flows into the power conversion module 20 and the rear-wheel drive system 10, thereby cooling the power conversion module 20 and the rear-wheel drive system 10. The cooling water flowing out of the rear-wheel drive system 10 flows through the second cooling water flow path 41b and flows into the battery 6, thereby cooling the battery 6. The cooling water flowing out of the battery 6 flows through the second cooling water flow path 41b and merges midway in the first cooling water flow path 41a, which connects the radiator 43 and the water-cooled capacitor 44.

[0043] The other portion of the second cooling water flow path 41b, which branches off from the water heater 52, flows into the front-wheel drive system 30, cooling the front-wheel drive system 30. In the front-wheel drive system 30, heat generated by energizing the coils (at least one of the field coil and the armature coil) of the winding excitation motor 31 is transferred through the motor shaft 31a, the housing 39, and the cooling plate 37. Heat is exchanged with the cooling water flowing through the interior of the cooling plate 37, raising the temperature of the cooling water. The heated cooling water then flows out of the front-wheel drive system 30, merges with the second cooling water flow path 41b, which also contains cooling water flowing from the battery 6, and flows into the heat exchange system 40. In other words, the heat generated by energizing the winding excitation motor 31 of the front-wheel drive system 30 is supplied to the heat exchange system 40. Thus, the second cooling water flow path 41b, which cools the front-wheel drive system 30, does not extend toward the rear of the four-wheel drive vehicle 1 but is located only in front of the vehicle. Hereinafter, the second cooling water flow path 41b flowing out of the water heater 52, circulating in the front wheel drive device 30, and before merging with the second cooling water flow path 41b through which the cooling water flows out of the battery 6 is circulated may be sometimes referred to as the third cooling water flow path 41c (an example of a cooling water flow path).

[0044] like Figure 4 As shown, the refrigerant circuit 42 includes an annular refrigerant flow path 42a that sequentially circulates the refrigerant through the compressor 51, water-cooled capacitor 44, cooler 46, interior capacitor 48, evaporator 49, and accumulator 50. The refrigerant, compressed by the compressor 51 and converted into a high-temperature compressed gas, flows into the water-cooled capacitor 44, where the cooling water removes heat and condenses and liquefies the refrigerant. The refrigerant flowing out of the water-cooled capacitor 44 removes heat from the cooling water and evaporates, becoming vaporized, in the cooler 46. The refrigerant flowing out of the cooler 46 heats the air in the interior capacitor 48. The heated air becomes warm air and is used to heat the vehicle interior. When heating the vehicle interior, the evaporator 49 is not used. The refrigerant flowing out of the interior capacitor 48, still in its vaporized state, flows into the accumulator 50. In the accumulator 50, if the vaporized refrigerant contains liquid, the liquid refrigerant is separated. Thereafter, the vaporized refrigerant flows out of the accumulator 50 and flows back to the compressor 51 , where it is compressed again to become a high-temperature compressed gas.

[0045] On the other hand, when cooling the vehicle interior, interior capacitor 48 is not used, but evaporator 49 is used. Specifically, the refrigerant vaporized in cooler 46 flows into evaporator 49, where it removes heat from the air. The refrigerant, having removed heat from the air, flows out of evaporator 49, flows into accumulator 50, and then returns to compressor 51. The air from which heat has been removed becomes cold air and is used to cool the vehicle interior.

[0046] [Structure of heat exchange module]

[0047] like Figure 4 、 Figure 5 As shown, the heat exchange system 40 of this embodiment includes a heat exchange module 60. The heat exchange module 60 is an integrated module that integrates a water-cooled capacitor 44, a cooler 46, an electric pump 47, and a accumulator 50 mounted on a manifold 61. This manifold 61 internally defines a first cooling water flow path 41a, a second cooling water flow path 41b, and a portion of the refrigerant flow path 42a. The structures of the water-cooled capacitor 44, the cooler 46, the electric pump 47, and the accumulator 50 are well known, and therefore a detailed description thereof will be omitted.

[0048] [Effects of this embodiment]

[0049] In this embodiment, the rear-wheel drive system 10 and the power conversion module 20 are integrated. This reduces the overall volume and improves space efficiency compared to separate configurations. Furthermore, by aligning the rear-wheel drive system 10 and the power conversion module 20 horizontally and integrating them, the overall height can be reduced, allowing for placement near the rear wheels 3. Furthermore, the high-voltage wiring and cooling water wiring (second cooling water flow path 41b), which were previously used by the rear-wheel drive system 10 and the power conversion module 20, can be shared.

[0050] In this embodiment, a coil-excitation motor 31 is used as the drive motor for the front-wheel drive device 30. Therefore, for example, when the four-wheel drive vehicle 1 is stopped and the temperature of the cooling water cooling the coil-excitation motor 31 is below a predetermined temperature, the coil-excitation motor 31 is used to energize the field coil and armature coils, generating heat without generating a rotating magnetic field. This allows the coil-excitation motor 31 to generate heat without rotating. Consequently, even when the four-wheel drive vehicle 1 is stopped, the cooling water flowing through the third cooling water flow path 41c can be heated to raise its temperature. The heat contained in the cooling water can then be supplied to the battery 6 to preheat it or to an air conditioner (not shown) to heat the vehicle interior.

[0051] Furthermore, the use of the coil-excited motor 31 can reduce drag loss compared to a permanent magnet motor and improve energy efficiency during regenerative braking compared to an induction motor.

[0052] The permanent magnet motor 11 is advantageous at low speeds and low rotations, while the coil-excitation motor 31 is advantageous at high speeds and high rotations. In this embodiment, the permanent magnet motor 11 is used in the rear-wheel drive system 10, and the coil-excitation motor 31 is used in the front-wheel drive system 30, thereby ensuring driving performance from low speeds to high speeds.

[0053] Typically, the cabin air conditioning system is located at the front of the vehicle. Therefore, by placing the heat exchange system 40 near the front wheels 4 of the four-wheel drive vehicle 1, the length of the piping used to circulate the cooling water and refrigerant from the heat exchange system 40 to the air conditioning system can be shortened. As a result, particularly during heating, the cooling water heated by the heat (waste heat) generated by the front-wheel drive system 30 and the second inverter 33 is used for heating without being cooled. This improves heat utilization efficiency and reduces power consumption.

[0054] The heat exchange system 40 of this embodiment includes a heat exchange module 60 including a manifold 61. A first cooling water flow path 41a, a second cooling water flow path 41b, and a portion of a refrigerant flow path 42a are integrated within the manifold 61. This eliminates the need for separate piping for the first cooling water flow path 41a, the second cooling water flow path 41b, and the refrigerant flow path 42a, thereby reducing the manufacturing effort and miniaturization of the heat exchange system 40.

[0055] The heat exchange system 40 of this embodiment includes a heat exchange module 60 in which a water-cooled capacitor 44, a cooler 46, an electric pump 47, and a accumulator 50 are mounted on a manifold 61 to form an integrated structure.

[0056] The heat exchange system 40 of this embodiment includes a heat exchange module 60 that integrates the functions of the accumulator 50 by attaching the water-cooled capacitor 44, the cooler 46, and the electric pump 47 to a manifold 61. This allows the heat exchange system 40 to be miniaturized.

[0057] [Other Implementation Methods]

[0058] (1) In the above embodiment, the power converter 34 and the second inverter 33 are arranged on the front side of the vehicle, but the power converter 34 can also be integrated into the power supply unit 22 located on the rear side of the four-wheel drive vehicle 1, or part of the circuit of the power converter 34 and the second inverter 33 can be integrated into the power supply unit 22.

[0059] (2) The heat exchange module 60 may have a structure in which the function of the accumulator 50 is formed in the manifold 61 , and the manifold 61 and the accumulator 50 are integrated.

[0060] (3) In the heat exchange module 60, at least one of the water-cooled capacitor 44, the cooler 46, the electric pump 47, and the accumulator 50 may not be mounted on the manifold 61. Furthermore, in the heat exchange module 60, at least one of the heater core 45, the interior capacitor 48, the evaporator 49, the compressor 51, and the water heater 52 may be mounted together with or in place of at least one of the water-cooled capacitor 44, the cooler 46, the electric pump 47, and the accumulator 50 to form an integrated system.

[0061] (4) In the above embodiment, the cooling water flowing through the second cooling water flow path 41 b is used for preheating and cooling the battery 6 . However, the refrigerant flowing through the refrigerant flow path 42 a or insulating oil such as paraffin may be used.

[0062] [Overview of the above embodiment]

[0063] Hereinafter, the above-described vehicle electric drive device 2 will be described.

[0064] In one embodiment of the electric drive device 2 for a vehicle, a rear wheel 3 side of a four-wheel drive vehicle 1 having a rear-wheel drive mode and a four-wheel drive mode is provided with: a rear-wheel drive device 10, which includes a permanent magnet motor 11 driven by power from a battery 6 and transmitting a driving rotational force to the rear wheel 3, and a first power transmission mechanism 12; and a power conversion module 20, which integrates a first inverter 21 that operates the rear-wheel drive device 10 and a power supply unit 22 connected to the battery 6 and performing power conversion. On the front wheel 4 side of the above-mentioned four-wheel drive vehicle 1, a front-wheel drive device 30 is provided, which includes a winding-excited motor 31 that transmits a driving rotational force to the front wheel 4 and a second power transmission mechanism 32; and a heat exchange system 40, which has a heat transfer mechanism for utilizing waste heat from the front-wheel drive device 30 and the second inverter 33 for an air conditioning device, and the rear-wheel drive device 10 and the power conversion module 20 are integrated.

[0065] In a high-output four-wheel drive vehicle 1, traction is applied to the rear wheels 3 during acceleration. Therefore, in this embodiment, by using a permanent magnet motor 11, which is advantageous at low speeds and low rotations, in the rear-wheel drive device 10, smooth acceleration can be achieved. Furthermore, in this embodiment, the rear-wheel drive device 10 and the power conversion module 20 are arranged at the rear of the four-wheel drive vehicle 1. This allows the high-voltage wiring and cooling water wiring required for the rear-wheel drive device 10 and the power conversion module 20, respectively, to be centrally arranged, minimizing the layout of wiring and piping. This reduces the space occupied by the vehicle electric drive device 2 in the four-wheel drive vehicle 1.

[0066] In this embodiment, a coil-excitation motor 31 is used as the drive motor for the front-wheel drive system 30. When using the coil-excitation motor 31, the field coil and armature coil are energized so as not to generate a rotating magnetic field. This allows the coil-excitation motor 31 to generate heat without rotating. This allows the cooling water used to cool the coil-excitation motor 31 to be heated and used to heat the vehicle cabin even when the four-wheel drive vehicle 1 is parked.

[0067] Typically, the cabin air conditioning system is located at the front of the vehicle. Therefore, by placing the heat exchange system 40 at the front of the four-wheel drive vehicle 1, as in this embodiment, the length of the piping used to circulate the cooling water and refrigerant from the heat exchange system 40 to the air conditioning system can be shortened. As a result, particularly during heating, the cooling water heated by the heat (waste heat) generated by the front-wheel drive system 30 and the second inverter 33 is not cooled but used for heating. This improves heat utilization efficiency and reduces power consumption.

[0068] Furthermore, integrating the rear-wheel drive system 10 and the power conversion module 20 can reduce the overall volume and improve space efficiency compared to separate configurations. Furthermore, high-voltage wiring and cooling water wiring used in the rear-wheel drive system 10 and the power conversion module 20 can be shared.

[0069] As described above, in the four-wheel drive vehicle 1 in which the front and rear wheels are rotated by respective drive motors, it is possible to provide the vehicle electric drive device 2 that is configured in a manner suitable for high output and can achieve improvements in power consumption and the like.

[0070] Furthermore, the heat exchange system 40 preferably includes a heat exchange module 60 including a manifold 61 integrating cooling water flow paths 41 a and 41 b through which cooling water flows and a refrigerant flow path 42 a through which refrigerant flows.

[0071] As in this method, if the heat exchange system 40 has a heat exchange module 60, and the heat exchange module 60 includes a manifold 61 that integrates the cooling water flow paths 41a, 41b for the circulation of cooling water and the refrigerant flow path 42a for the circulation of refrigerant, there is no need for additional piping of the flow paths, thereby reducing the manufacturing time of the heat exchange system 40 and miniaturizing the heat exchange system 40.

[0072] In addition, the heat exchange module 60 preferably includes a liquid reservoir 50 integrated with the manifold 61 .

[0073] As in this embodiment, if the heat exchange module 60 includes the accumulator 50 integrated with the manifold 61 , the heat exchange system 40 can be miniaturized.

[0074] In addition, the heat exchange module 60 preferably includes the condenser 44 and the evaporator 46 integrated with the manifold 61 .

[0075] As in this embodiment, if the heat exchange module 60 includes the condenser 44 and the evaporator 46 integrated with the manifold 61 , the heat exchange system 40 can be miniaturized.

[0076] In addition, it is preferred that when the four-wheel drive vehicle 1 stops, when the temperature of the cooling water cooling the winding excitation motor 31 is below the specified temperature, the winding excitation motor 31 is energized to generate heat, thereby raising the temperature of the cooling water, and supplying the heat of the rising cooling water to the battery 6 and the air conditioning device.

[0077] According to this embodiment, the battery 6 can be preheated or the vehicle interior can be heated without driving the four-wheel drive vehicle 1 .

[0078] Furthermore, it is preferable that the heat generated by energizing the coil-excited motor 31 is transferred through the motor shaft 31 a , the housing 39 , and the cooling plate 37 and supplied to the heat exchange system 40 .

[0079] According to this embodiment, heat generated by energizing the coil-excited motor 31 can be supplied to the heat exchange system 40 and effectively utilized.

[0080] [Possibility of Industrial Application]

[0081] The present disclosure can be utilized in an electric drive device for a vehicle.

[0082] Description of Reference Numerals

[0083] 1...four-wheel drive vehicle; 2...vehicle electric drive device; 3...rear wheel; 4...front wheel; 10...rear-wheel drive device; 11...permanent magnet motor; 12...first power transmission mechanism; 20...power conversion module; 21...first inverter; 22...power supply unit; 30...front-wheel drive device; 31...winding-field motor; 31a...motor shaft; 32...second power transmission mechanism; 33...second inverter; 37...cooling plate; 39...housing; 40...heat exchange system; 41a...first cooling water flow path (cooling water flow path); 41b...second cooling water flow path (cooling water flow path); 41c...third cooling water flow path (cooling water flow path); 42a...refrigerant flow path; 44...water-cooled capacitor (condenser); 46...cooler (evaporator); 50...liquid reservoir; 60...heat exchange module; 61...manifold.

Claims

1. A vehicle electric drive device, wherein: On the rear wheel side of a four-wheel drive vehicle having a rear-wheel drive mode and a four-wheel drive mode, there are: A rear wheel drive device including a permanent magnet motor powered and driven by a battery and transmitting driving rotational force to the rear wheels, and a first power transmission mechanism; and a power conversion module that integrates a first inverter for operating the rear-wheel drive device and a power supply unit connected to the battery and performing power conversion; The four-wheel drive vehicle is provided with: A front wheel drive device including a winding-excited motor that transmits driving rotational force to the front wheels and a second power transmission mechanism; and a heat exchange system having a heat transfer mechanism for utilizing waste heat from the front wheel drive device and the second inverter for an air conditioner, The rear wheel drive device is integrated with the power conversion module.

2. The electric drive device for a vehicle according to claim 1, wherein: The heat exchange system includes a heat exchange module including a manifold that integrates a cooling water flow path through which cooling water flows and a refrigerant flow path through which refrigerant flows.

3. The electric drive device for a vehicle according to claim 2, wherein: The heat exchange module has a reservoir integrated with the manifold.

4. The electric drive device for a vehicle according to claim 2, wherein: The heat exchange module has a condenser and an evaporator integrated with the manifold.

5. The electric drive device for a vehicle according to claim 1, wherein: When the four-wheel drive vehicle stops, when the temperature of the cooling water cooling the winding excitation motor is below a specified temperature, the winding excitation motor is energized to generate heat, thereby raising the temperature of the cooling water, and the heat of the cooling water with a raised temperature is supplied to the battery and the air conditioning device.

6. The electric drive device for a vehicle according to claim 1 or 5, wherein: Heat generated by energizing the winding-excited motor is supplied to the heat exchange system through the motor shaft, the housing, and the cooling plate.

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