JP2020150577A - Left and right wheel drive device - Google Patents

Abstract

To provide a left and right wheel drive device which reduces unintended torque difference between left and right wheels.SOLUTION: In a left and right wheel drive device 15 comprising a first motor 1 and a second motor 2 which drive left and right wheels of a vehicle, and a gear mechanism 8 which amplitudes a torque difference therebetween and transmits to the left and right wheels, a mechanical pump 3 is provided on a power transmission path between the first motor 1 and the gear mechanism 8. A refrigerant discharged from the pump 3 is introduced into the first motor 1 via a first refrigerant passage 4, and is introduced into the second motor 2 via a second refrigerant passage 5. A calculation part 11, which calculates a loss torque derived from operation of the pump 3 and a torque addition value of the first motor 1 on the basis of the number of revolutions of the first motor 1, is provided. Further, a control part 12, which controls the first motor 1 so as to generate a torque in which the torque addition value is added to a request torque of the first motor 1, is provided.SELECTED DRAWING: Figure 1

Description

The present invention relates to a left and right wheel drive device for driving the left and right wheels of a vehicle.

Conventionally, in a vehicle drive device in which the left and right wheels of a vehicle are driven by an electric motor, an oil pump for cooling the electric motor is driven by the electric motor. That is, a mechanical oil pump (mechanical pump) is interposed in the power transmission path of the electric motor, and the electric motor is cooled by the cooling oil discharged from the oil pump. The driving force input to such an oil pump increases as the rotation speed of the electric motor increases, and acts to increase the discharge amount of the cooling oil. Therefore, it is possible to secure the cooling performance according to the traveling speed of the vehicle (see Patent Document 1).

Japanese Patent No. 5478595

In the existing technology, when two electric motors are mounted on the vehicle, the oil pump is driven by one of the electric motors. On the other hand, since a drive loss is generated by operating the oil pump, the load and the rotation speed of the two electric motors may become imbalanced, and the driving force of each of the left and right wheels may become unstable. In particular, in a left-right wheel drive device having a gear mechanism (differential mechanism or planetary gear mechanism) that amplifies the torque difference between the two electric motors and transmits them to each of the left and right wheels, the same torque is generated in the two electric motors. Even so, there will be a constant torque difference between the left and right wheels.

One of the purposes of this case is to reduce the unintended torque difference between the left and right wheels with respect to the left and right wheel drive devices, which was created in view of the above problems. Not limited to this purpose, it is also possible to exert an action / effect derived from each configuration shown in the “mode for carrying out the invention” described later, which cannot be obtained by the conventional technique. It can be positioned as a purpose.

(1) The disclosed left and right wheel drive devices amplify the torque difference between the first motor and the second motor that drive the left and right wheels of the vehicle and the first motor and the second motor and transmit the torque difference to each of the left and right wheels. It is a left and right wheel drive device provided with a gear mechanism. The apparatus includes a mechanical pump that is connected to a power transmission path between the first motor and the gear mechanism and discharges the refrigerant supplied to the first motor and the second motor.

Further, it is provided with a calculation unit that calculates a loss torque derived from the operation of the pump and a torque addition value of the first motor for compensating for the loss torque based on the rotation speed of the first motor. Further, a control unit for controlling the first motor is provided so that a torque obtained by adding the torque addition value to the required torque of the first motor is generated.

(2) A first refrigerant passage for introducing the refrigerant discharged from the pump into the first motor and a second refrigerant passage for introducing the refrigerant discharged from the pump into the second motor may be provided. preferable. Further, it is preferable that the first refrigerant passage has a cross section larger than that of the second refrigerant passage.

(3) A first valve that is interposed in the first refrigerant passage and controls the flow rate of the refrigerant that is supplied to the first motor, and a first valve that is interposed in the second refrigerant passage and supplied to the second motor. It is preferable to provide a second valve for controlling the flow rate of the refrigerant. Further, it is preferable that the control unit controls the opening degree of the first valve and the second valve according to the traveling state of the vehicle.

(4) The flow rate of the refrigerant supplied by the control unit to one of the first motor and the second motor, which transmits a larger driving force to the turning outer ring than to the turning inner ring, increases and is supplied to the other. It is preferable to control the opening degree of the first valve and the second valve so that the flow rate of the refrigerant is reduced.

(5) The flow rate of the refrigerant supplied by the control unit to one of the first motor and the second motor, which transmits more driving force to the turning inner ring than to the turning outer ring, increases and is supplied to the other. It is preferable to control the opening degree of the first valve and the second valve so that the flow rate of the refrigerant is reduced.

In other words, the flow rate of the refrigerant supplied by the control unit to one of the first motor and the second motor, which has a larger output motor torque (or motor driving force), increases, and the other It is preferable to control the opening degree of the first valve and the second valve so that the flow rate of the supplied refrigerant is reduced.

By adding the loss torque derived from the operation of the pump to the required torque of the first motor, the unintended torque difference between the left and right wheels can be reduced.

It is a schematic diagram for demonstrating the structure of the left-right wheel drive device as an embodiment. It is a collinear diagram which shows the relationship between the rotation speed of a motor and the rotation speed of the left and right wheels. It is a graph which shows the relationship between the motor rotation speed and the loss torque. It is a flowchart for demonstrating the control procedure of a motor. It is a flowchart for demonstrating an example of a valve control procedure. It is a flowchart for demonstrating an example of a valve control procedure.

[1. Constitution]
Hereinafter, a left and right wheel drive device as an embodiment will be described with reference to the drawings. This device is applied to the AYC device 15 of the vehicle shown in FIG. The AYC device 15 is a differential device for a vehicle having an AYC (active yaw control) function, and is interposed between the left and right wheels. The AYC function is a function that adjusts the magnitude of the yaw moment by independently controlling the sharing ratio of the driving force (driving torque) in the left and right drive wheels, thereby stabilizing the posture of the vehicle in the yaw direction. The AYC device 15 of the present embodiment has not only the AYC function but also a function of transmitting a rotational force to the left and right wheels to drive the vehicle and a function of passively absorbing the difference in the number of rotations of the left and right wheels generated when the vehicle turns. Also have.

The first motor 1, the second motor 2, and the pump 3 are built in the AYC device 15. The first motor 1 is located on the right side of the vehicle and the second motor 2 is located on the left side. These first motor 1 and second motor 2 are AC motors driven by the electric power of a battery (not shown), and preferably have substantially the same output characteristics. The torque of the left and right drive wheels is variable, and the torque difference between the first motor 1 and the second motor 2 is amplified and transmitted to each of the left and right wheels.

In the present embodiment, each of the first motor 1 and the second motor 2 has a right shaft 13 connected to the right wheel and a left shaft 14 connected to the left wheel via a gear mechanism 8 (differential mechanism, planetary gear mechanism, etc.). Connected to. The first motor 1, the right shaft 13, the left shaft 14, and the second motor 2 are capable of transmitting rotational force to each other. The first motor 1 transmits a larger driving force to the right shaft 13 than the left shaft 14, and the second motor 2 transmits a larger driving force to the left shaft 14 than the right shaft 13.

As shown in FIG. 2, each rotation speed is a value that is linearly arranged in the order of "first motor 1, right axis 13, left axis 14, second motor 2" on the collinear diagram. Therefore, the difference in the number of rotations of the left and right drive wheels is proportional to the difference in the number of rotations of the first motor 1 and the second motor 2. Further, when the rotation speeds of the first motor 1 and the second motor 2 are the same, the rotation speeds of the left and right drive wheels are also the same. Assuming that the loads on the left and right drive wheels are the same, the magnitude relationship between the torques of the first motor 1 and the second motor 2 is directly reflected in the magnitude relationship between the torques of the left and right drive wheels.

Subsequently, the cooling structure of the first motor 1 and the second motor 2 will be described. As shown in FIG. 1, the first motor 1 is interposed in the first cooling oil passage 4 (first refrigerant passage), and the second motor 2 is interposed in the second cooling oil passage 5 (second refrigerant passage). To. These cooling oil passages 4 and 5 are refrigerant passages in which cooling oil that lubricates the first motor 1 and the second motor 2 while being cooled circulates. In FIG. 1, the cooling oil circulates counterclockwise inside the first cooling oil passage 4 and clockwise inside the second cooling oil passage 5. Further, of the first cooling oil passage 4 and the second cooling oil passage 5, the sections in which the return oil from the first motor 1 and the second motor 2 circulate are merged into one.

A pump 3 is interposed in the confluence section of the first cooling oil passage 4 and the second cooling oil passage 5. The pump 3 is a mechanical pumping device (mechanical pump) that discharges cooling oil (refrigerant) supplied to each of the first motor 1 and the second motor 2. The pump 3 is connected to at least a power transmission path between the first motor 1 and the gear mechanism 8. Preferably, the pump 3 is connected to the rotating shaft of the first motor 1 via a reduction gear (not shown). When the pump 3 is connected to the rotation shaft of the motor 1, the rotation speed of the pump 3 is the same as that of the first motor 1 as shown in the collinear diagram of FIG. When the pump 3 is connected to the rotation shaft of the motor 1 via a reduction gear, the rotation speed of the pump 3 is proportional to the rotation speed of the first motor 1 as shown by the broken line in FIG. Can take the value of.

The power for driving the pump 3 is mainly provided by the first motor 1. As shown in FIG. 3, the relationship between the drive loss torque on the axle derived from the operation of the pump 3 and the rotation speed of the first motor 1 increases as the motor rotation speed increases, and the loss torque increases. The relationship is such that the gradient decreases. In this way, the size of the torque cross generated by driving the pump 3 can be calculated based on the rotation speed of the first motor 1.

A first valve 6 is interposed in the first cooling oil passage 4, and a second valve 7 is interposed in the second cooling oil passage 5. The valves 6 and 7 are arranged near the points where the two cooling oil passages 4 and 5 branch off from the confluence section. The first valve 6 is a flow rate control valve that controls the flow rate of the cooling oil supplied to the first motor 1, and the second valve 7 is a flow rate control that controls the flow rate of the cooling oil supplied to the second motor 2. It is a valve.

The cross-sectional area of the first cooling oil passage 4 is preferably set to a value larger than the cross-sectional area of the second cooling oil passage 5. As a result, the first motor 1 is more easily cooled than the second motor 2, and the torque difference due to the temperature difference between the motors 1 and 2 is less likely to occur. On the other hand, the flow rate of the cooling oil in each of the cooling oil passages 4 and 5 can be controlled by adjusting the opening degrees of the first valve 6 and the second valve 7. Therefore, the cross-sectional area of the first cooling oil passage 4 may be the same as the cross-sectional area of the second cooling oil passage 5. In the configuration in which the first valve 6 and the second valve 7 are omitted, the cross-sectional area of the first cooling oil passage 4 may be set to a large cross-sectional area of the second cooling oil passage 5.

The operating states of the motors 1 and 2 and the valves 6 and 7 are controlled by the control device 10. The control device 10 is an electronic control device (computer) that performs control for reducing an unintended torque difference between the left and right wheels. The control device 10 contains a processor (central processing unit), a memory (main memory), a storage device (storage), an interface device, and the like, and these are connected via an internal bus. Further, an accelerator opening sensor 16, a vehicle speed sensor 17, and a steering angle sensor 18 are connected to the control device 10.

The accelerator opening degree sensor 16 is a sensor that detects the amount of depression of the accelerator pedal (accelerator opening degree). The vehicle speed sensor 17 is a sensor that detects the traveling speed (vehicle speed) of the vehicle, and the steering angle sensor 18 is a sensor that detects the steering angle of the steering wheel. The information detected by these sensors 16 to 18 is used to calculate the torque and output magnitude (that is, required torque, required output, etc.) required for each of the first motor 1 and the second motor 2. To be done.

If the vehicle is equipped with an electronic control unit (AYC-ECU) for controlling the AYC function, the total torque and torque difference between the left and right drive wheels and the rotation of each motor 1 and 2 can be obtained from this electronic control unit. It is also possible to grasp the required torque of each motor 1 and 2 by acquiring information such as the number, energizing current value, voltage value, and frequency. In this case, the above sensors 16 to 18 can be omitted.

As shown in FIG. 1, a calculation unit 11 and a control unit 12 are provided inside the control device 10. These elements are shown by classifying the functions of the control device 10 for convenience, and are provided as software executed by using the hardware resources of the control device 10. Each element may be described as an independent program, or may be described as a composite program having a plurality of functions.

The calculation unit 11 calculates the loss torque (driving loss torque on the axle) derived from the operation of the pump 3 and the torque addition value for compensating for the loss torque (driving loss torque on the axle) based on the rotation speed of the first motor 1. The loss torque can be calculated based on the motor rotation speed of the first motor 1 by using a map or a mathematical formula as shown in FIG. Further, the torque addition value is a value obtained by dividing the loss torque by the reduction gear ratio in the power transmission path from the first motor 1 to the right shaft 13.

The control unit 12 has a function of controlling the operating state of the first motor 1 and the second motor 2 based on at least the torque addition value calculated by the calculation unit 11. Here, the first motor 1 is controlled so that a torque having a magnitude obtained by adding a torque addition value to the required torque of the first motor 1 is generated. On the other hand, the second motor 2 is controlled so that the required torque of the second motor 2 is generated. The control states of the first motor 1 and the second motor 2 are illustrated below.

As shown in Table 1, in the present embodiment, the loss torque derived from the operation of the pump 3 is compensated by the first motor 1. For example, when the required torque of the second motor 2 is a predetermined value A during straight running, the required torque of the first motor 1 is also set to the predetermined value A in the conventional example. As a result, an axle torque difference having a magnitude obtained by multiplying the on-axle drive loss torque by the torque difference amplification factor (reduction gear ratio in the power transmission path from the pump 3 to the right shaft 13) is generated. On the other hand, in the present embodiment, in order to make the drive torque difference (axle torque difference) between the left and right wheels 0, the torque corresponding to the sum of the predetermined value A and the torque addition value (axle drive loss torque / reduction gear ratio). Is generated in the first motor 1. This reduces at least the unintended torque difference between the left and right wheels. Further, the drive torque difference (axle torque difference) between the left and right wheels becomes 0 when the vehicle travels straight.

Further, the control unit 12 also has a function of controlling the opening degree of the first valve 6 and the second valve 7 according to the traveling state of the vehicle. The opening degree of the first valve 6 and the second valve 7 is the flow rate of the cooling oil supplied to one of the first motor 1 and the second motor 2 which transmits more driving force to the turning outer ring than to the turning inner ring. Controlled to increase. For example, when the vehicle turns to the right, the opening degree of the second valve 7 is controlled in the opening direction so that the flow rate on the second motor 2 side increases. At this time, the opening degree of the first valve 6 is controlled in the closing direction. Preferably, the opening degree of the first valve 6 and the second valve 7 is controlled so that the flow rate of the cooling oil supplied to the first motor 1 is larger than the flow rate of the cooling oil supplied to the second motor 2. Will be done.

On the contrary, when the vehicle turns to the left, the opening degree of the first valve 6 is controlled in the opening direction, and the opening degree of the second valve 7 is controlled in the closing direction. Preferably, the opening degree of the first valve 6 and the second valve 7 is controlled so that the flow rate of the cooling oil supplied to the first motor 1 is smaller than the flow rate of the cooling oil supplied to the second motor 2. Will be done. These controls make it difficult for torque differences due to heat generation and temperature differences between the motors 1 and 2 to occur.

Since the output of the first motor 1 is slightly larger than the output of the second motor 2 when the vehicle is traveling straight, the amount of hydraulic oil supplied to the first motor 1 is supplied to the second motor 2. It is conceivable to increase the amount of hydraulic oil slightly. However, when the calorific value difference and the temperature difference due to the output difference between the first motor 1 and the second motor 2 are sufficiently small, the first valve 6 and the second valve are made so that the hydraulic oil amounts are almost the same. The opening degree of 7 may be controlled.

[2. flowchart]
FIG. 4 is a flowchart for explaining the control procedure of the motors 1 and 2 by the control device 10. This flow is repeatedly executed at a predetermined cycle during the operation of the motors 1 and 2. The calculation unit 11 calculates the loss torque (axle drive loss torque) derived from the operation of the pump 3 based on the rotation speed of the first motor 1 (step A1).

Further, the torque loss value is calculated by dividing the loss torque by the reduction gear ratio in the power transmission path from the first motor 1 to the right shaft 13 (step A2). After that, the control unit 12 controls the first motor 1 and the second motor 2 so that the loss torque is compensated. At this time, the output of the second motor 2 is controlled so that the required torque is generated as usual. On the other hand, the output of the first motor 1 is controlled so that a torque obtained by adding a torque addition value to the required torque is generated (step A3).

FIG. 5 is a flowchart for explaining the control procedure of the valves 6 and 7 by the control device 10. This flow is also repeatedly executed at a predetermined cycle during the operation of the motors 1 and 2. Here, the operating states of the valves 6 and 7 are classified into three types [when turning left, when turning right, and when not (when traveling straight or when stopped)] according to the turning condition of the vehicle. The turning state of the vehicle can be determined based on, for example, the steering angle of the steering wheel and the slip state of the left and right wheels (steps B1 and B2).

When turning to the left, the opening degrees of the first valve 6 and the second valve 7 are controlled so that the flow rate of the cooling oil supplied to the first motor 1 is larger than the flow rate of the cooling oil supplied to the second motor 2. Is done (step B3). On the other hand, when turning to the right, the first valve 6 and the second valve 7 are opened so that the flow rate of the cooling oil supplied to the second motor 2 is larger than the flow rate of the cooling oil supplied to the first motor 1. The degree is controlled (step B4). Further, in the case of neither left turn nor right turn, the flow rate of the cooling oil supplied to the first motor 1 is larger than the flow rate of the cooling oil supplied to the second motor 2, as in step B3. In addition, the opening degrees of the first valve 6 and the second valve 7 are controlled (step B5). By such control, the torque difference due to the heat generation amount and the temperature difference of the motors 1 and 2 is less likely to occur.

FIG. 6 is a modified example in which the determination conditions in steps B1 and B2 of FIG. 5 are changed. Here, instead of determining the turning direction of the vehicle, the magnitude relationship between the torque output from the first motor 1 (right motor torque) and the torque output from the second motor 2 (left motor torque) is determined. Toque. In step C1, it is determined whether or not the left motor torque is smaller than the right motor torque. On the contrary, in step C2, it is determined whether or not the left motor torque is larger than the right motor torque.

For example, even when the vehicle is turning left, the left motor torque may be larger than the right motor torque due to the occurrence of slip. In such a case, the condition of step C2 is satisfied, and the flow rate of the cooling oil supplied to the second motor 2 is larger than the flow rate of the cooling oil supplied to the first motor 1. The opening degree of the second valve 7 is controlled (step C4).

On the contrary, when the vehicle is turning to the right, the left motor torque may be smaller than the right motor torque. In such a case, the condition of step C1 is satisfied, and the flow rate of the cooling oil supplied to the first motor 1 is larger than the flow rate of the cooling oil supplied to the second motor 2. The opening degree of the second valve 7 is controlled (step C3). When the left and right motor torques are the same, the flow rate of the cooling oil supplied to the first motor 1 is larger than the flow rate of the cooling oil supplied to the second motor 2, as in the control of FIG. In addition, the opening degrees of the first valve 6 and the second valve 7 are controlled (step C5). By such control, the torque difference due to the heat generation amount and the temperature difference of the motors 1 and 2 is less likely to occur.

[3. effect]
(1) In the above-described embodiment, the loss torque and the torque addition value are calculated based on the rotation speed of the first motor 1, and the torque obtained by adding the torque addition value to the required torque of the first motor 1 is generated. , The first motor 1 is controlled. In this way, by adding the loss torque derived from the operation of the pump 3 to the required torque of the first motor 1, the unintended torque difference between the left and right wheels can be reduced. Further, when the drive torques of the left and right wheels are the same, the theoretical torque difference can be set to 0.

(2) By making the cross section of the first cooling oil passage 4 larger than the cross section of the second cooling oil passage 5, the flow path resistance of the first cooling oil passage 4 can be reduced, and the pump 3 is connected. It is possible to make the first motor 1 to be cooled more easily than the second motor 2. Therefore, the torque difference due to the temperature difference between the motors 1 and 2 can be reduced.

It should be noted that a large cross-sectional area of the first cooling oil passage 4 means that it is advantageous in improving the cooling performance when turning left rather than when turning right. In general, although there is no big difference in the frequency of right-turning and left-turning, the turning radius when turning left is smaller than the turning radius when turning left on a road traveling on the left side, and the first motor 1 (turning left) The amount of heat generated by the right motor, which transmits a large amount of driving force to the right wheel, which is the outer ring for turning at the time, tends to increase. Therefore, in countries such as Australia, the United Kingdom, Southeast Asia, and India where the road network for left-hand traffic is widespread, including Japan, the left and right motors 1 and 2 can be increased by increasing the cross-sectional area of the first cooling oil passage 4. Can be cooled efficiently.

(3) Each motor 1 is provided by interposing a first valve 6 and a second valve 7 in the first cooling oil passage 4 and the second cooling oil passage 5 and controlling the valve opening degree according to the traveling state of the vehicle. The flow rate of the cooling oil supplied to, and 2 can be adjusted accurately, and the left and right motors 1 and 2 can be cooled efficiently. Further, even if the cross-sectional areas of the first cooling oil passage 4 and the second cooling oil passage 5 are the same, the flow rate of the cooling oil flowing through the respective cooling oil passages 4 and 5 can be freely adjusted.

(4) The valve opening of the first valve 6 and the second valve 7 is such that the flow rate of the cooling oil supplied to the motors 1 and 2 which transmit more driving force to the turning outer ring than to the turning inner ring increases. Is controlled by. In this way, by increasing the amount of cooling oil to the motors 1 and 2 on the turning outer ring side where the temperature tends to rise, the temperature difference between the motors 1 and 2 can be reduced, and the drive torque difference can be reduced. .. Therefore, the unintended torque difference between the left and right wheels can be reduced, and the torque stability can be improved.

(5) Further, the drive torque of the left and right motors 1 and 2 is not always larger on the turning outer ring side than on the turning inner ring side. For example, if slipping occurs during turning, the drive torque on the turning inner ring side may increase or the driving torque on the turning outer ring side may decrease, and the driving torque on the turning inner ring side may be greater than the driving torque on the turning outer ring side. May also grow temporarily. In such a case, the temperature difference between the motors 1 and 2 should be reduced by increasing the flow rate of the cooling oil supplied to the motors 1 and 2 which transmit more driving force to the turning inner ring than the turning outer ring. And the drive torque difference can be reduced. Therefore, the unintended torque difference between the left and right wheels can be reduced, and the torque stability can be improved.

[4. Modification example]
The above embodiment is merely an example, and there is no intention of excluding the application of various modifications and techniques not specified in the present embodiment. Each configuration of the present embodiment can be variously modified and implemented without departing from the gist thereof. In addition, it can be selected as needed, or can be combined as appropriate. In the above-described embodiment, the cooling device is described using the cooling oil as the refrigerant, but the type of the refrigerant does not matter. For example, cooling water may be used instead of cooling oil.

1 1st motor 2 2nd motor 3 Pump 4 1st cooling oil passage 5 2nd cooling oil passage 6 1st valve 7 2nd valve 8 Gear mechanism 10 Control device 11 Calculation unit 12 Control unit 15 AYC device

Claims (5)

A left and right wheel drive device including a first motor and a second motor for driving the left and right wheels of a vehicle, and a gear mechanism for amplifying a torque difference between the first motor and the second motor and transmitting the torque difference to each of the left and right wheels. In
A mechanical pump connected to a power transmission path between the first motor and the gear mechanism and discharging a refrigerant supplied to the first motor and the second motor.
A calculation unit that calculates the loss torque derived from the operation of the pump and the torque addition value of the first motor for compensating for the loss torque based on the rotation speed of the first motor.
A left and right wheel drive device including a control unit that controls the first motor so that a torque obtained by adding the torque addition value to the required torque of the first motor is generated. A first refrigerant passage for introducing the refrigerant discharged from the pump into the first motor,
A second refrigerant passage for introducing the refrigerant discharged from the pump into the second motor is provided.
The left and right wheel drive device according to claim 1, wherein the first refrigerant passage has a cross section larger than that of the second refrigerant passage. A first refrigerant passage for introducing the refrigerant discharged from the pump into the first motor,
A second refrigerant passage for introducing the refrigerant discharged from the pump into the second motor,
A first valve interposed in the first refrigerant passage and controlling the flow rate of the refrigerant supplied to the first motor.
It is provided with a second valve interposed in the second refrigerant passage and controlling the flow rate of the refrigerant supplied to the second motor.
The left and right wheel drive device according to claim 1 or 2, wherein the control unit controls the opening degree of the first valve and the second valve according to the traveling state of the vehicle. The flow rate of the refrigerant supplied by the control unit to one of the first motor and the second motor to transmit a larger driving force to the turning outer ring than to the turning inner ring is increased, and the refrigerant is supplied to the other. The left and right wheel drive device according to claim 3, wherein the opening degree of the first valve and the second valve is controlled so that the flow rate of the refrigerant is reduced. The flow rate of the refrigerant supplied by the control unit to one of the first motor and the second motor to transmit a larger driving force to the turning inner ring than to the turning outer ring is increased, and the refrigerant is supplied to the other. The left and right wheel drive device according to claim 3, wherein the opening degree of the first valve and the second valve is controlled so that the flow rate of the refrigerant is reduced.

Images