JP2018121429A - Electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric automobile configured so that four wheels can be driven independently, which can efficiently cool motors or inverters for travelling and driving.SOLUTION: The electric automobile comprises: four motors 5; four inverters 9afor controlling the motors 5; first and second pumps Pand Pfor circulating coolant to the four inverters 9a; and first and second radiators Rand Rfor cooling the coolant. The first pump Pcirculates coolant to individual cooling paths 15 of the two inverters 9aand 9acorresponding to a left front wheel 2L and a right rear wheel 1R, and the first radiator Rcools the coolant. The second pump Pcirculates coolant to individual cooling paths 15 of the two inverters 9aand 9acorresponding to a right front wheel 2R and a left rear wheel 1L, and the second radiator Rcools the coolant.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an electric vehicle capable of independently driving four wheels, and relates to an electric vehicle capable of efficiently cooling each motor or inverter for driving.

  In an electric vehicle equipped with four driving motors, when cooling the four motors or four inverters controlling these motors with a set of radiators and pumps, the individual cooling paths to be cooled are It is conceivable to connect in series or in parallel (Patent Documents 1 and 2).

Japanese Patent No. 3443296 Japanese Patent No. 5417123

When the individual cooling paths of the four motors are connected in series, the cooling water temperature rises on the downstream side of the cooling flow path, so that sufficient cooling performance cannot be obtained on the motor arranged on the downstream side of the cooling flow path. . Therefore, the downstream motor is limited by overheating protection earlier than other upstream motors, and the downstream motor always has a higher temperature than other upstream motors. Becomes worse.
In addition, when the cooling flow path is divided into a plurality of flow paths and the individual cooling paths of the four motors are connected in parallel, a sufficient flow rate cannot be obtained and the cooling performance of all the motors is lowered. In addition to being easily restricted by overheat protection, durability is deteriorated.

  An object of the present invention is to provide an electric vehicle capable of efficiently cooling each motor or each inverter for driving driving in an electric vehicle capable of independently driving four wheels.

An electric vehicle according to the present invention is an electric vehicle in which a motor device having a motor for driving and an inverter for controlling the motor is provided corresponding to each of the four wheels, and the four wheels can be driven independently. ,
A first pump that circulates coolant through individual cooling paths of two motor devices corresponding to the left front wheel and the right rear wheel of the four wheels;
A first radiator for cooling the coolant circulated by the first pump;
A second pump for circulating coolant through the individual cooling paths of the two motor devices corresponding to the right front wheel and the left rear wheel among the four wheels;
A second radiator for cooling the coolant circulated by the second pump.
The “individual cooling path of the motor device” means “individual cooling path formed in the motor”, “individual cooling path formed in the inverter”, or both.

  According to this configuration, the first pump circulates the coolant through the individual cooling paths of the two motor devices corresponding to the left front wheel and the right rear wheel on the diagonal. Further, the first radiator cools the coolant circulated by the first pump. The second pump circulates coolant through the individual cooling paths of the two motor devices corresponding to the diagonally right front wheel and left rear wheel. Further, the second radiator cools the coolant circulated by the second pump.

  As described above, since the cooling system is divided into two systems, that is, a cooling system that is cooled by the first pump and the first radiator, and a cooling system that is cooled by the second pump and the second radiator, a pair of pumps and radiators are used. The temperature rise of the coolant can be distributed more than the conventional example in which the individual cooling paths of the four motors are connected in series or in parallel. Therefore, in each cooling system, the temperature rise of the motor or inverter arrange | positioned downstream can be suppressed, and durability of each motor and each inverter can be improved rather than a prior art example.

  Further, in order to improve the turning performance of the vehicle, there are cases where control is performed to reduce the torque of the two wheels on the turning inner wheel side and increase the torque of the two wheels on the turning outer wheel side among the four wheels. When performing this control, the individual cooling paths corresponding to the diagonal drive wheels are cooled by the two cooling systems, respectively, so that the temperature rise of the coolant can be dispersed and suppressed. Can be simplified. In other words, since there is only one cooling system per diagonal, there is only one motor or inverter on the turning outer ring side in one cooling system, so the temperature rise of the coolant is distributed and suppressed, and the command torque is easily determined Can do. If the above control is performed and there are two motors on the turning outer ring side in one cooling system, the downstream motor on the turning outer ring side has a higher temperature than the downstream motor on the turning inner ring side, The control system for determining the command torque becomes complicated.

  A first circulation path in which each individual cooling path connected to the first pump and the first radiator is connected in series, and each individual cooling path connected to the second pump and the second radiator are connected in series. And a second circulation path. In this case, it is possible to improve the cooling performance by increasing the flow rate of the coolant rather than connecting the individual cooling paths to each circulation path in parallel.

  Any one of the four wheels before and after the four wheels is a main drive wheel and the other two wheels are sub drive wheels, and the two motor devices that drive the main drive wheel are connected to the first circulation path, An upstream individual cooling path with respect to the first pump and an upstream individual cooling path with respect to the second pump in the second circulation path may be provided. In this way, by setting the motor device that drives the main drive wheel upstream of each circulation path, the motor that corresponds to the main drive wheel that is always used is cooled better than the motor that corresponds to the sub drive wheel. be able to. Thereby, torque can be more largely distributed to the main drive wheels than the sub drive wheels, and the acceleration performance of the electric vehicle can be improved.

In the first circulation path, on the upstream side with respect to the first pump, individual cooling paths of two inverters of the motor device corresponding to the left front wheel and the right rear wheel are provided, and in the first circulation path, On the downstream side of the first pump, there are provided individual cooling paths for two motors of the motor device corresponding to the left front wheel and the right rear wheel,
In the second circulation path, on the upstream side with respect to the second pump, individual cooling paths of two inverters of the motor device corresponding to the right front wheel and the left rear wheel are provided, and in the second circulation path, An individual cooling path for two motors of the motor device corresponding to the right front wheel and the left rear wheel may be provided downstream of the second pump.

The switching element of the inverter has a very high rate of temperature rise compared to the temperature rise of the stator and rotor of the motor. For this reason, even if the water temperature of the inverter exceeds the allowable temperature even temporarily, the maximum current cannot flow through the inverter in that state. If the maximum current is allowed to flow through the inverter in that state, the allowable temperature of the switching element will be exceeded and the switching element will be damaged.
According to this configuration, the individual cooling path of the inverter is provided on the upstream side of each circulation path, and the individual cooling path of the motor is provided on the downstream side, so that the inverter having a relatively smaller heat capacity than the motor is preferentially cooled. Can do. Therefore, it is possible to prevent the allowable temperature of the switching element of the inverter from being exceeded.

  The in-wheel motor drive device may be configured by the motor, a wheel bearing that rotatably supports the driving wheel, and a speed reducer that decelerates the rotation of the motor and transmits it to the wheel bearing.

  An electric vehicle according to the present invention is an electric vehicle in which a motor device having a motor for driving and an inverter for controlling the motor is provided corresponding to each of the four wheels, and the four wheels can be driven independently. A first pump that circulates the coolant in the individual cooling paths of the two motor devices corresponding to the left front wheel and the right rear wheel of the four wheels, and a first radiator that cools the coolant circulated by the first pump A second pump that circulates coolant in the individual cooling paths of the two motor devices corresponding to the right front wheel and the left rear wheel of the four wheels, and a second that cools the coolant circulated by the second pump. And the radiator, each motor or each inverter for driving driving can be efficiently cooled.

1 is a block diagram showing a schematic configuration of an electric vehicle according to an embodiment of the present invention. It is sectional drawing which shows an example of the in-wheel motor drive device of the same electric vehicle. It is a block diagram of the inverter apparatus of the same electric vehicle. It is a figure which shows an example of the cooling system of the same electric vehicle. It is sectional drawing which shows the separate cooling path of the inverter of the inverter apparatus. It is a figure which shows the cooling system of the electric vehicle which concerns on other embodiment of this invention. It is a figure which shows the cooling system of the electric vehicle which concerns on further another embodiment of this invention. It is a figure which shows the cooling system of the electric vehicle which concerns on further another embodiment of this invention.

An electric vehicle according to an embodiment of the present invention will be described with reference to FIGS.
<About schematic configuration of electric vehicle>
As shown in FIG. 1, in the electric vehicle according to this embodiment, the left rear wheel 1L and the right rear wheel 1R are each driven by a motor 5 for driving driving, and the left front wheel 2L and the right front wheel 2R are respectively driving for driving. This is a four-wheel drive electric vehicle driven by a motor 5. The left rear wheel 1L, the right rear wheel 1R, the left front wheel 2L, and the right front wheel 2R may be collectively referred to as drive wheels. In this example, the left rear wheel 1L and the right rear wheel 1R among the four wheels are main drive wheels, and the left front wheel 2L and the right front wheel 2R are auxiliary drive wheels. Each motor 5 can be driven independently. This motor 5 is in-wheel together with a wheel bearing 6 that rotates and supports each drive wheel, and a speed reducer 7 that decelerates and transmits the rotation of the motor 5 to an inner member that also serves as a hub-rotating wheel of the wheel bearing 6. The motor drive device 4 is configured.

<About in-wheel motor drive 4>
FIG. 2 is a cross-sectional view showing an example of the in-wheel motor drive device 4. The wheel bearing 6 includes a double row rolling element interposed between an outer member 6a serving as a fixed wheel and an inner member 6b serving as a rotating wheel, and the wheel provided on the inner member 6b. A wheel 11 and a brake disk 12 are attached to the attachment flange 6ba.

  The motor 5 includes a stator 5b fixed to the housing 13 and a rotor 5a that rotates to face the stator 5b. The rotor shaft 5aa of the rotor 5a is rotatably mounted on the housing 13 via bearings 14 and 14. The The motor 5 is, for example, an AC motor such as a synchronous motor in which a stator 5b is provided with a coil (not shown) and a rotor 5a is provided with a permanent magnet (not shown). The speed reducer 7 includes a cycloid speed reducer (not shown) or other gear train that decelerates the rotation of the rotor shaft 5aa of the motor 5 and transmits it to the inner member 6b of the wheel bearing 6.

<About control system>
As shown in FIG. 1, each motor 5 is rotationally driven via each inverter device 9 by electric power of a battery 8. FIG. 3 is a block diagram of the inverter device 9. Each inverter device 9 is composed of a plurality of power devices 9aa composed of switching elements, and converts an inverter 9a that converts DC power of the battery 8 into three-phase AC power, and a motor that is a drive control circuit that controls the inverter 9a. And a control unit 9b. A motor device Ms including each motor 5 and an inverter 9a corresponding to the motor 5 is configured. For example, an IGBT or a MOSFET is applied as the switching element. The motor control unit 9b controls the output of the inverter 9a by PWM control or the like in accordance with a drive command for each motor 5 given from an ECU (electronic control unit) 10 (FIG. 1) serving as a host control means.

  As shown in FIG. 1, the ECU 10 is a means for performing overall control and cooperative control of the entire vehicle, and includes a microcomputer, its control program, and an electronic circuit. The ECU 10 is provided with motor control means 31 for controlling each motor 5 and storage means 35. The motor control unit 31 includes a command torque calculation unit 31 a that calculates a command torque in response to an accelerator input that is a signal indicating the amount of depression of the accelerator operation unit 32 such as an accelerator pedal, and the inverter unit of each motor 5. And a command torque distributing means 31b for distributing the power to 9.

  More specifically, the command torque calculation unit 31a calculates the command torque by taking into account the deceleration input of the brake operation means 33 such as a brake pedal in addition to the accelerator input. The command torque distribution means 31b calculates and outputs the command torque distributed to each inverter 9a according to the command torque calculated by the command torque calculation unit 31a, the steering angle input of the steering 34, and the like. The torque distribution ratio may be obtained by calculation using a calculation formula, or may be calculated from a map provided in the storage unit 35. Parameters necessary for the torque distribution ratio or the calculation formula for obtaining the torque distribution ratio are determined by, for example, simulation or experiment, and are stored in the storage unit 35 so as to be rewritable. The command torque distribution means 31b determines the command torque to be distributed to each inverter 9a based on the torque distribution ratio calculated from the calculation formula or set in the map. The motor-specific command torque output from the command torque distribution means 31b is input to the inverter device 9, and converted into drive currents for the motors 5 by the inverter 9a.

<About the cooling system>
FIG. 4 is a diagram illustrating an example of a cooling system of the electric vehicle. In this example, the individual cooling paths 15 formed in the inverters 9a ₁ , 9a ₃ , 9a ₂ , 9a ₄ are applied as the individual cooling paths 15 of the motor device Ms (FIG. 3). The electric vehicle is provided with a first pump _{P 1} and the first radiator _{R 1,} and a second pump _{P 2} and the second radiator _{R 2.} The individual cooling paths 15 and 15 corresponding to the diagonals of the wheels shown in plan view in FIG. 4 are cooled by two cooling systems. Specifically, the first pump P ₁ supplies the coolant to the individual cooling paths 15 of the two inverters 9a ₁ and 9a ₃ corresponding to the two motors 5 and 5 that respectively drive the left front wheel 2L and the right rear wheel 1R. Circulate. The first radiator R ₁ cools the cooling liquid.

The second pump _{P 2} circulates a cooling fluid to the two inverters _9a 2, 9a ₄ of the individual cooling channels 15 corresponding to the two motors 5, 5 for driving the right front wheel 2R and the left rear wheel 1L, respectively. The second radiator R ₂ cools the coolant. The first and second radiators R ₁ and R ₂ are, for example, installed side by side on the front part of the vehicle body that easily hits the traveling wind. A so-called water pump is applied as the first and second pumps P ₁ and P ₂ .
Although the motor 5 is cooled by air cooling, the inverter 9a _{1 to 4} it is also possible to cool the water-cooled by different cooling systems.

The first pump P ₁ is connected by piping in series with the first downstream radiator R _1, downstream of the first pump P _1, sequentially, individual cooling passage 15 of the inverter 9a ₃ corresponding to the right rear wheel 1R, the left front wheel The individual cooling path 15 of the inverter 9a ₁ corresponding to 2L is piped in series. Further since the first radiator R ₁ in the individual cooling passages 15 of the downstream-side inverter 9a ₁ is connected by piping to constitute a first circulation path J _1. Upstream of the first circulation path J _1, arranged inverters 9a ₃ which is one of the main driving wheels for the right rear wheel 1R, downstream of the first circulation path J _1, one of the auxiliary drive wheels They are arranged a certain inverter 9a ₁ for the left front wheel 2L.

The second pump P ₂ is connected by piping in series downstream of the second radiator R _2, downstream of the second pump P _2, sequentially, individual cooling passage 15 of the inverter 9a ₄ corresponding to the left rear wheel 1L, the right front wheel The individual cooling path 15 of the inverter 9a ₂ corresponding to 2R is piped in series. Further, the second radiator R ₂ is connected by piping to the individual cooling path 15 of the inverter 9 a ₂ on the downstream side, thereby configuring the _second circulation path J ₂ . Upstream of the second circulation path J _2, an inverter 9a ₄ for the left rear wheel 1L, which is one of the main driving wheels arranged, downstream of the second circulation path J _2, one of the auxiliary drive wheels It is arranged inverter 9a ₂ for some right front wheel 2R.

FIG. 5 is a cross-sectional view (cross-sectional view taken along line VV in FIG. 4) showing the individual cooling path 15 of each inverter 9a.
An inverter 9 a is fixed on the cooling unit 16. The inverter 9a in this example is, for example, an IGBT module 17 in which a plurality of semiconductor elements are housed in a single rectangular package. The cooling unit 16 is provided with a coolant reservoir 16a through which coolant is supplied and discharged. On the lower surface of the IGBT module 17, a plurality of radiating fins 17 a for radiating heat generated from the semiconductor element are provided. The IGBT module 17 is fixed on the cooling unit 16 in a state where the heat radiation fins 17 a are inserted into the cooling liquid reservoir 16 a of the cooling unit 16. The cooling liquid reservoir 16a is formed in a rectangular hole shape covered with the lower surface of the IGBT module 17 so as not to interfere with the heat radiating fins 17a corresponding to the locations where the plurality of heat radiating fins 17a are provided.

  The cooling unit 16 is provided with a water supply passage 16b for supplying the coolant to the coolant reservoir 16a and a drain passage 16c for draining the coolant from the coolant reservoir 16a. In this example, a water supply path 16b including a through hole communicating with the coolant pool 16a is formed at one end of the cooling unit 16. An internal thread portion for pipe connection is provided at one end portion of the water supply passage 16b. An inlet hose joint 18 is screwed into the female thread portion. A water supply pipe 19 is connected to the inlet hose joint 18.

At the other end of the cooling unit 16, a drainage channel 16 c formed of a through hole communicating with the coolant pool 16 a is formed. A female thread portion for pipe connection is provided at one end portion of the drainage channel 16c. The outlet hose joint 20 is screwed to the female female part. A drain pipe 19 is connected to the outlet hose joint 20. Therefore, the cooling liquid can be circulated in the circulation paths J ₁ and J ₂ over the cooling liquid pool 16a of each inverter 9a by the pumps P ₁ and P ₂ and the radiators R ₁ and R ₂ to cool the cooling liquid.

<Effect>
According to the electric vehicle described above, second cooling system, a cooling system for cooling the first pump P ₁ and the first radiator R _1, a second pump P ₂ and a second cooling system that cools the radiator R ₂ Since the system is divided, the temperature rise of the coolant can be dispersed with a pair of pumps and radiators, compared to the conventional example in which four individual cooling paths are connected in series or in parallel. Accordingly, in the cooling system, to suppress the temperature rise of the inverter 9a _1, 9a ₂ disposed on the downstream side, the durability of each inverter 9a _{1 to 4} can be made higher than the conventional example.

Further, in order to improve the turning performance of the vehicle, there are cases where control is performed to reduce the torque of the two wheels on the turning inner wheel side and increase the torque of the two wheels on the turning outer wheel side among the four wheels. Specifically, the command torque distribution means 31b (FIG. 1) is configured so that the front and rear of the turning outer wheel side is larger than the total torque of the front and rear wheels on the turning inner wheel side during turning of the vehicle to which the steering angle of the steering 34 (FIG. 1) is input. the total torque of the wheel determines the command torque to be distributed to each inverter 9a _{1 to 4} to be larger.

  In the case of performing the control at the time of turning the vehicle, the temperature increase of the coolant can be dispersed and suppressed by cooling the individual cooling paths 15 corresponding to the diagonals of the drive wheels by the two cooling systems. In addition, the control system can be simplified. Since there is only one inverter corresponding to the motor 5 on the turning outer wheel side in one cooling system, the temperature rise of the coolant can be dispersed and suppressed, and the command torque can be easily determined.

Since the individual cooling paths 15 are connected in series to the first and second circulation paths J ₁ and J ₂ , the flow rate of the coolant is increased as compared to the individual cooling paths connected to the circulation paths in parallel. Thus, the cooling performance can be improved.
By making the inverters 9a ₃ and 9a ₄ corresponding to the main drive wheels upstream of the circulation paths J ₁ and J ₂ , the inverters 9a ₃ and 9a ₄ corresponding to the main drive wheels that are always used correspond to the sub drive wheels. It is possible to cool better than the inverters 9a ₁ and 9a ₂ . Thereby, torque can be more largely distributed to the main drive wheels than the sub drive wheels, and the acceleration performance of the electric vehicle can be improved.

<About other embodiments>
In the following description, the same reference numerals are given to portions corresponding to the matters described in advance in the respective embodiments, and overlapping descriptions are omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

The cooling system shown in FIG. 6 may be used. In this example, the individual cooling paths 15 formed in the motors ₅₁ to ₄ are applied as the individual cooling paths 15 of the motor device Ms (FIG. 3). In FIG. 6, a so-called motor-on-board type in which four motors ₅₁ to ₄ that independently drive the four wheels are installed on the vehicle body. The first pump P ₁ and the first radiator R ₁ circulate the coolant through the individual cooling paths 15 of the two motors 5 ₁ and 5 ₃ that drive the left front wheel 2L and the right rear wheel 1R, respectively, and cool the coolant To do. Second pump P ₂ and the second radiator R ₂ is and is circulated a cooling fluid to the two motors 5 _2, 5 ₄ of the individual cooling channels 15 for driving the right front wheel 2R and the left rear wheel 1L, respectively cooling the cooling liquid To do.

The individual cooling path 15 of each of the motors _{51 to 4} includes, for example, a cooling water path provided spirally in the vicinity of the axial direction in the motor housing where the stator is disposed. Of the four wheels, the left rear wheel 1L and the right rear wheel 1R are main drive wheels, and the left front wheel 2L and the right front wheel 2R are auxiliary drive wheels. The embodiment of FIG. 6 also has the same operational effects as the above-described embodiment.

The cooling system shown in FIG. 7 may be used. As the individual cooling paths 15 of the motor device Ms (FIG. 3) of this example, both the individual cooling paths 15 of the motors and the individual cooling paths 15 of the inverters are applied. The same applies to FIG. 8 described later. In FIG. 7, in the motor-on-board format, the main driving wheels are the left rear wheel 1L and the right rear wheel 1R, and cooling is prioritized over the cooling system of FIG. As shown in FIG. 7, the first circulation path J _1, the first downstream pump P _1, sequentially, individual cooling passage 15 of the inverter 9a ₃ corresponding to the right rear wheel 1R, the inverter corresponding to the left front wheel 2L 9a ₁ of the individual cooling passages 15, the motor _{5 3} separate cooling path 15 corresponding to the right rear wheel 1R, the motor _{5 1} a separate cooling path 15 corresponding to the left front wheel 2L is connected by piping. The first radiator R ₁ is piping connected further to the motor 5 ₁ a separate cooling path 15 corresponding to the downstream of the left front wheel 2L.

In the second circulation path _{J 2,} a second downstream of the pump _{P 2,} sequentially, individual cooling passage 15 of the inverter 9a ₄ corresponding to the left rear wheel 1L, the inverter 9a ₂ corresponding to the right front wheel 2R individual cooling passage 15 , the motor 5 ₄ separate cooling path 15 corresponding to the left rear wheel 1L, motor 5 ₂ separate cooling channels 15 corresponding to the right front wheel 2R is connected by piping. The second radiator R ₂ is a pipe connected to the motor 5 ₂ separate cooling path 15 further corresponding to the most downstream of the right front wheel 2R. The individual cooling path 15 of each of the motors _{51 to 4} includes, for example, a cooling water path provided spirally in the vicinity of the axial direction in the motor housing where the stator is disposed. The same _{applies to} the individual cooling paths 15 of the motors _{51 to 4} in FIG.

The switching element of the inverter has a very high rate of temperature rise compared to the temperature rise of the stator and rotor of the motor. For this reason, even if the water temperature of the inverter exceeds the allowable temperature even temporarily, the maximum current cannot flow through the inverter in that state. If the maximum current flows through the inverter when the inverter water temperature exceeds the allowable temperature, the switching element will be exceeded and the switching element will be damaged, so the inverter water temperature normally exceeds the allowable temperature. If so, apply current limit.
According to the configuration of FIG. 7, the individual cooling paths 15 of the inverters 9a ₃ , 9a ₁ , 9a ₄ , 9a ₂ are provided upstream of the circulation paths J ₁ , J ₂ , and the motors 5 ₃ , 5 ₁ are provided downstream. Since the 5 ₄ and 5 ₂ individual cooling paths 15 are provided, the inverters 9a ₁ to ₄ having a relatively smaller heat capacity than the motors 5 to ₄ can be preferentially cooled. Therefore, it is possible to prevent the allowable temperature of the switching elements of the inverters 9a _{1 to 4} from being exceeded.

In FIG. 8, in the motor-on-board format, the main drive wheels are the left rear wheel 1L and the right rear wheel 1R, and priority is given to wiring and the like over the cooling system of FIG. As shown in FIG. 8, in the first circulation path J _1, the first downstream pump P _1, sequentially, the individual cooling passages 15 inverter 9a ₁ corresponding to the left front wheel 2L, inverter corresponding to the right rear wheel 1R 9a ₃ of the individual cooling passages 15, the motor _{5 3} separate cooling path 15 corresponding to the right rear wheel 1R, the motor _{5 1} a separate cooling path 15 corresponding to the left front wheel 2L is connected by piping. The first radiator R ₁ is piping connected further to the motor 5 ₁ a separate cooling path 15 corresponding to the downstream of the left front wheel 2L.

In the second circulation path _{J 2,} a second downstream of the pump _{P 2,} sequentially, in the right of the individual cooling passages 15 inverter 9a ₂ corresponding to the front wheels 2R, inverter 9a ₄ corresponding to the left rear wheel 1L individual cooling passage 15 , the motor 5 ₄ separate cooling path 15 corresponding to the left rear wheel 1L, motor 5 ₂ separate cooling channels 15 corresponding to the right front wheel 2R is connected by piping. The second radiator R ₂ is a pipe connected to the motor 5 ₂ separate cooling path 15 further corresponding to the most downstream of the right front wheel 2R.
According to the configuration of FIG. 8, it may be positioned proximate the inverters 9a _1-4 and the motor 5 _1-4 corresponding to the drive wheels. Thereby, the power lines between the inverters 9a _{1 to 4} and the motors 5 _{1 to 4} corresponding to the respective drive wheels can be shortened, and accordingly, cost reduction and noise emission can be reduced.

  In an in-wheel motor drive device, a cycloid reducer, a planetary reducer, a parallel two-axis reducer, and other reducers can be applied, and even a so-called direct motor type that does not employ a reducer. Good.

  As mentioned above, although the form for implementing this invention based on embodiment was demonstrated, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1L ... Left rear wheel 1R ... Right rear wheel 2L ... Left front wheel 2R ... Right front wheel 4 ... In-wheel motor drive devices 5, 5 _1-4 ... Motor 6 ... Wheel bearing 7 ... Speed reducers 9a, 9a _1-4 ... Inverter 15 ... individual cooling passage Ms ... motor device _{P 1,} P 2 _... first, second pump _{R 1,} R 2 _... first, second radiator _{J 1,} J 2 _... first, second circulating path

Claims (5)

A motor device having a motor for driving and an inverter for controlling the motor is provided corresponding to each of the four wheels, and in the electric vehicle capable of independently driving the four wheels,
A first pump that circulates coolant in the individual cooling paths of the two motor devices corresponding to the left front wheel and the right rear wheel among the four wheels;
A first radiator for cooling the coolant circulated by the first pump;
A second pump for circulating coolant through the individual cooling paths of the two motor devices corresponding to the right front wheel and the left rear wheel among the four wheels;
An electric vehicle comprising: a second radiator that cools the coolant circulated by the second pump.   2. The electric vehicle according to claim 1, wherein each individual cooling path connected to the first pump and the first radiator is connected in series, and is connected to the second pump and the second radiator. And a second circulation path in which the individual cooling paths are connected in series.   3. The electric vehicle according to claim 2, wherein any one of the four wheels is a main drive wheel and the other two wheels are auxiliary drive wheels, and the two motor devices drive the main drive wheel. And an individual cooling path upstream of the first pump in the first circulation path and an individual cooling path upstream of the second pump in the second circulation path. The electric vehicle according to claim 2 or claim 3,
In the first circulation path, on the upstream side with respect to the first pump, there are provided individual cooling paths for two inverters of the motor device corresponding to the left front wheel and the right rear wheel,
In the first circulation path, on the downstream side of the first pump, two motor individual cooling paths of the motor device corresponding to the left front wheel and the right rear wheel are provided,
In the second circulation path, on the upstream side of the second pump, there are provided individual cooling paths for two inverters of the motor device corresponding to the right front wheel and the left rear wheel,
An electric vehicle in which two motor individual cooling paths of a motor device corresponding to the right front wheel and the left rear wheel are provided on the downstream side of the second circulation path with respect to the second pump. 5. The electric vehicle according to claim 1, wherein the motor, a wheel bearing that rotatably supports the drive wheel, and a deceleration that decelerates the rotation of the motor and transmits the reduced speed to the wheel bearing. 6. Electric vehicle that forms an in-wheel motor drive device with the machine.

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