JP2021005967A - Driving control device - Google Patents

Abstract

To provide a driving control device that can prevent a vehicle whose left and right driving wheels respectively can be driven independently by individual motors from behaving unstably by suppressing a difference in torque between the left and right driving wheels.SOLUTION: A overheating-time torque allocation change part 40, when a detected temperature at one motor side is equal to a first threshold or less, enables one motor 6 to output maximum torque; when the detected temperature at the one motor side is over the first threshold and equal to a second threshold or less, lowers the maximum torque that the one motor 6 can output as the detected temperature rises; and when the detected temperature at the one motor side is over the second threshold, brings torque of the one motor to zero. Even if a detected temperature at the other motor side is not over the first threshold, the part lowers the maximum torque that the other motor 6 can output, in accordance with a restriction on torque of the one motor 6; and when the detected temperature at the one motor side is over the second threshold, brings the torque to a restricted torque value set to a ratio α with respect to the maximum torque that the other motor 6 can output.SELECTED DRAWING: Figure 3

Description

The present invention relates to a drive control device, for example, in a wheel-independent drive type vehicle equipped with a motor for drive wheels such as an in-wheel motor, a motor for drive wheels, an oil for lubrication or cooling of a motor, a speed reducer, or the like. Alternatively, the present invention relates to a technique that enables safe running or provisional evacuation running when a semiconductor or the like of a drive control device is overheated.

Conventionally, a technique has been proposed in which a current limiting condition is set according to the region in which the temperature of the inverter is located and control is performed to limit the current command given to the inverter (Patent Document 1).
As another conventional technique, the current of the motor is limited when one or both of the temperatures detected by the oil temperature sensor and the temperature sensor provided on the motor stator exceed a predetermined threshold value. A technique has been proposed (Patent Document 2).

JP 2013-110926 Japanese Unexamined Patent Publication No. 2015-142415

In a wheel-independent drive type vehicle, for example, when only one wheel is limited by overheating during high-speed turning, a large unintended difference occurs in the torque generated by the left and right drive wheels, resulting in poor vehicle behavior. It may become stable.

An object of the present invention is to provide a drive control device capable of suppressing a torque difference between the left and right and preventing the behavior of the vehicle from becoming unstable in a vehicle in which the left and right drive wheels can be driven independently by individual motors. Is to provide.

The drive control device 16 of the present invention is a drive control device that controls the motors 6 and 6 of a vehicle in which the left and right drive wheels 2 and 2 can be driven independently by individual motors 6 and 6, respectively.
Temperature detecting means Ks for detecting the motor temperature of each of the motors 6 or the temperature of a portion affecting the change in the motor temperature, and
A torque limiting means 40 for limiting the torque of each of the motors 6 based on the detected temperature detected by the temperature detecting means Ks is provided.
The torque limiting means 40 is
When the detected temperature on one motor side detected by the temperature detecting means Ks is equal to or lower than the first threshold value, the one motor 6 can be output up to the maximum torque.
When the detection temperature on the one motor side exceeds the first threshold value and is equal to or lower than the second threshold value larger than the first threshold value, the maximum output possible by the one motor 6 as the detection temperature rises. Perform torque limit to lower the torque,
When the detection temperature on the one motor side exceeds the second threshold value, the torque of the one motor 6 is limited to zero.
Even if the detected temperature on the other motor side does not exceed the first threshold value, the torque limit that lowers the maximum torque that can be output by the other motor 6 is performed according to the torque limit of the one motor 6, and the one is said. When the detected temperature on the motor side of the motor exceeds the second threshold value, the torque limit value is set at a predetermined ratio to the maximum torque that can be output by the other motor 6.
The determined ratio is a ratio arbitrarily determined by design or the like, and is determined by obtaining an appropriate ratio by, for example, the heat resistant temperature of the component to be constructed and one or both of the test and the simulation.

According to this configuration, when the detection temperature on one motor side exceeds the first threshold value and the torque limit is applied to lower the maximum torque that can be output by the one motor 6, the torque limit of the one motor 6 is followed. Torque limitation is performed to reduce the maximum torque that can be output by the other motor 6. Therefore, it is possible to prevent the torque difference between the left and right drive wheels from becoming too large and the behavior of the vehicle from becoming unstable. When the detected temperature on one motor side exceeds the second threshold value, the minimum driving force is set to the torque limit value set at a specified ratio to the maximum torque that can be output by the other motor 6. Can be secured. As a result, a provisional evacuation run can be performed. By limiting the torque in this way, it is possible to suppress the overload of the motor 6 and stabilize the behavior of the vehicle.
The "one motor side" means one of the left and right drive wheels, which is a motor for driving one of the drive wheels, and a portion that affects a change in the motor temperature of the one motor.
The "parts that affect the change in motor temperature" are parts that change in temperature depending on the degree of heat generation of the motor when the temperature of the motor rises and falls, and parts in which a motor current that raises and lowers the temperature of the motor flows.
The former is, for example, a circulation flow path of a coolant that cools a motor, and the latter is, for example, a circulation flow path of a coolant that cools a switching element of an inverter device and the inverter device.

The inverter 31 is provided with an inverter 31 that converts DC power into AC power used to drive the motor 6 by opening and closing a plurality of switching elements.
The temperature detecting means Ks includes a temperature sensor 42 for a motor that detects the motor temperature of each motor 6, a temperature sensor 34 for an inverter that detects the temperature of each of the inverters 31, and oil for lubrication or cooling. Have at least two of the temperature sensors
In the torque limiting means 40, the detected temperatures detected by a plurality of temperature sensors 42 and 34 that detect at least two temperatures of the motor 6 that drives the same driving wheel, its inverter 31, and oil are measured. When the first threshold value corresponding to each is exceeded, the torque limit value of the motor 6 may be limited by the smallest value among the torque limit values obtained for each temperature sensor. By limiting the torque of the motor 6 in this way, the overload of the motor 6 can be suppressed more reliably.

The torque limiting means 40 has a torque limit value of the left and right drive wheels obtained according to the detection temperature of the temperature detecting means Ks on one motor side when the detected temperatures of both motors both exceed the first threshold value. Of the torque limit values of the left and right drive wheels obtained according to the detection temperature of the temperature detecting means Ks on the other motor side, the torque limit values of both motors 6 and 6 may be limited by a lower torque limit value. By adopting such a low torque limit value, when both motors 6 and 6 that drive the left and right drive wheels overheat, the overload of both motors 6 and 6 can be more reliably suppressed. ..

The torque limiting means 40 may change the predetermined ratio according to the vehicle speed.
In the invention of changing the ratio according to the vehicle speed, the torque limiting means 40 may set the predetermined ratio to be larger as the vehicle speed is lower and the predetermined ratio to be smaller as the vehicle speed is higher. Good. In this case, for example, during low-speed driving where a large torque difference between the left and right drive wheels has little effect, the torque limit value of the other motor 6 remains large, and a large torque difference between the left and right drive wheels has an effect on high speed. The torque limit value of the other motor 6 can be reduced during traveling.

The torque limiting means 40 may keep the predetermined ratio constant regardless of the vehicle speed. In this case, the software of the drive control device 16 can be simplified, and the cost can be reduced.

The torque limiting means 40 has a steering angle detecting means Dk for determining whether or not the vehicle is turning, and the torque limiting means 40 only when the steering angle detecting means Dk determines that the vehicle is turning. The torque of each motor 6 may be limited. In this case, the behavior of the vehicle during turning can be stabilized.

In the invention having the steering angle detecting means Dk, the torque limiting means 40 outputs the driving wheels on the side where the detected temperature does not exceed the first threshold value up to the maximum torque of the motor 6 while the vehicle is traveling straight. It may be possible. In this case, by increasing the driving force of the vehicle while the vehicle is traveling straight, the vehicle can travel on its own on a steep uphill road or the like.

In the invention having the steering angle detecting means Dk, the torque limiting means 40 sets the predetermined ratio α to "1" while the vehicle is traveling straight, and the greater the degree of turning of the vehicle by the steering angle detecting means Dk, the more the said. The defined ratio α may be reduced. By changing the ratio α according to the degree of turning of the vehicle in this way, the behavior of the vehicle during turning can be more reliably stabilized.

The motor 6 is an in-wheel motor drive device IWM including the motor 6, a wheel bearing 4 that supports the drive wheels, and a speed reducer 7 that reduces the rotation of the motor 6 and transmits it to the wheel bearing 4. May be configured. In the case of the in-wheel motor drive device IWM, as a result of compactness, the wheel bearing 4, the reduction gear 7 and the motor 6 are accompanied by a reduction in the amount of material used and a high-speed rotation of the motor 6, so their reliability is ensured. Is an important issue. The reliability of the in-wheel motor drive device IWM can be ensured by limiting the torque of each motor 6 based on the detected temperature and suppressing the overload of each motor 6.

The drive control device of the present invention is a drive control device that controls the motor of a vehicle in which the left and right drive wheels can be driven independently by individual motors, and the motor temperature of each motor or a change in the motor temperature. The torque limiting means includes a temperature detecting means for detecting the temperature of a portion affecting the temperature and a torque limiting means for limiting the torque of each motor based on the detected temperature detected by the temperature detecting means. When the detection temperature on one motor side detected by the temperature detecting means is equal to or lower than the first threshold value, the one motor can be output up to the maximum torque, and the detection temperature on the one motor side sets the first threshold value. When the value exceeds the first threshold value and is equal to or lower than the second threshold value, as the detection temperature rises, torque limitation is performed to reduce the maximum torque that can be output by the one motor, and the detection on the one motor side is performed. When the temperature exceeds the second threshold value, the torque of the one motor is limited to zero, and even when the detected temperature on the other motor side does not exceed the first threshold value, the torque limit of the one motor is limited. According to this, torque is limited to reduce the maximum torque that can be output by the other motor, and when the detected temperature on the one motor side exceeds the second threshold value, the maximum torque that can be output by the other motor is applied. Set to the torque limit value set to the specified ratio. Therefore, for a vehicle in which the left and right drive wheels can be driven independently by individual motors, it is possible to suppress the torque difference between the left and right and prevent the behavior of the vehicle from becoming unstable.

It is a block diagram of the conceptual structure which shows the vehicle which mounted the drive control device which concerns on embodiment of this invention in a plan view. It is sectional drawing of the in-wheel motor drive device in the vehicle. It is a block diagram of the control system of the drive control device. It is a figure which shows the example of the case where overheating occurs on the left wheel side. It is a figure which shows the example of the case where overheating occurs in both the left and right wheels. It is a figure which shows the example of the ratio which limits the torque. It is a figure which shows the characteristic of the rotation speed and output torque of a motor. It is a block diagram of the conceptual structure which shows the vehicle which mounted the drive control device which concerns on another Embodiment of this invention in the plan view.

[First Embodiment]
An embodiment of the present invention will be described with reference to FIGS. 1 to 7.
<Conceptual composition of vehicle>
FIG. 1 is a block diagram having a conceptual configuration showing a vehicle equipped with the drive control device according to this embodiment in a plan view. This vehicle is a four-wheel electric vehicle in which wheels 2 serving as left and right rear wheels of the vehicle body 1 are used as driving wheels, and wheels 3 serving as left and right front wheels are used as driving wheels. The wheel 3 serving as the front wheel is a steering wheel. The left and right wheels 2 and 2, which are the driving wheels, are driven by a traveling motor 6 that can be driven independently. Each motor 6 constitutes an in-wheel motor drive device IWM, which will be described later. Brakes are provided on each of the wheels 2 and 3. The wheels 3 and 3, which are the steering wheels that are the left and right front wheels, can be steered via a steering mechanism (not shown), and are steered by a steering means 15 such as a steering wheel.

<About the outline configuration of the in-wheel motor drive device IWM>
As shown in FIG. 2, the left and right in-wheel motor drive devices IWM each have a motor 6, a wheel bearing 4 that supports the wheels, and a speed reducer 7 that reduces the rotation of the motor 6 and transmits it to the wheel bearing 4. And some or all of these are placed in the wheel. The rotation of the motor 6 is transmitted to the wheels 2 which are the driving wheels via the speed reducer 7 and the wheel bearings 4. A brake rotor 5 constituting the brake is fixed to the flange portion of the hub wheel 4a of the wheel bearing 4, and the brake rotor 5 rotates integrally with the wheel 2.

The motor 6 is a three-phase motor, for example, an embedded magnet type synchronous motor in which a permanent magnet is built in the core portion of the rotor 6a. The motor 6 is a motor provided with a radial gap between the stator 6b fixed to the housing 8 and the rotor 6a attached to the rotary output shaft 9. The motor 6 is cooled by oil (coolant) that also lubricates and cools the speed reducer 7. The oil flows through the circulation flow path Jr.

<About control system>
FIG. 3 is a block diagram of the control system of the drive control device 16. The drive control device 16 includes a vehicle control ECU 14 which is an electric control unit that controls the entire vehicle, an inverter device 13 that controls the left and right motors 6 and 6 for traveling according to a command torque of the vehicle control ECU 14, and sensors. And have. When the vehicle is an electric vehicle, the vehicle control ECU is also referred to as a VCU (Vehicle Control Unit).

The vehicle control ECU 14 has a command torque calculation unit 47 and a torque distribution means 48. The command torque calculation unit 47 generates acceleration / deceleration commands given to the left and right motors 6 and 6 as command torque from the acceleration command output by the accelerator sensor 51 and the deceleration command output by the brake sensor 53. The accelerator sensor 51 detects the amount of operation of the accelerator operating means 20 such as the accelerator pedal, and outputs an acceleration command according to the detected amount of operation. The brake sensor 53 detects the amount of operation of the brake operating means 21 such as the brake pedal, and outputs a deceleration command according to the detected amount of operation. The torque distribution means 48 outputs the command torque calculated by the command torque calculation unit 47 to the inverter device 13 so as to distribute the command torque to the left and right motors 6 and 6.

The inverter device 13 has power circuit units 28, 28 provided for each motor 6, and a motor control unit 29 that controls these power circuit units 28, 28. The motor control unit 29 includes motor drive control units 30 and 30 corresponding to each motor 6, torque distribution changing unit 40 during overheating as a torque limiting means, switching element temperature detection units 39 and 39, and motor temperature detection units 43 and 43. The oil temperature detecting units 45 and 45 and the speed detecting means 41 are provided. The motor control unit 29 has a function of outputting each information such as detection values and control values of the in-wheel motor drive device IWM (FIG. 1) of the motor control unit 29 to the vehicle control ECU 14.

Each power circuit unit 28 has an inverter 31 that converts the DC power of the battery Bt (FIG. 1) into three-phase AC power used for driving each motor 6, and a PWM driver 32 that drives the inverter 31. Each inverter 31 is composed of a bridge circuit including a plurality of switching elements.
The motor control unit 29 is composed of a computer, a program executed by the computer, and an electronic circuit, and has motor drive control units 30 and 30 as a basic control unit thereof. Each motor drive control unit 30 controls each system individually.

Each motor drive control unit 30 calculates a current command corresponding to a command torque given from the vehicle control ECU 14 via the torque distribution change unit 40 at the time of overheating, and in response to this current command, the detected motor current is transmitted from the current sensor 38. The current feedback control to obtain and follow is performed. Each motor drive control unit 30 calculates a voltage command by current feedback control, and gives a voltage command to the PWM driver 32 of the power circuit unit 28. Further, the motor drive control unit 30 obtains the rotation angle of the rotor 6a (FIG. 2) of the motor 6 from the rotation angle detecting means 33 and performs vector control.

The overheated torque distribution changing unit 40, which is a torque limiting means, limits the torque of each motor 6 based on the detected temperature detected by the temperature detecting means Ks.
The temperature detecting means Ks detects the motor temperature of each motor 6 or the temperature of a portion that affects the change in the motor temperature. Examples of the portion that affects the change in the motor temperature include a circulation flow path of oil (cooling liquid) that lubricates and cools the switching element and the speed reducer. The temperature detection means Ks of this embodiment includes a temperature sensor 42 for each motor, a motor temperature detection unit 43 thereof, a temperature sensor 34 for each inverter 31, a switching element temperature detection unit 39 thereof, and oil for each speed reducer. It has a temperature sensor 44 and an oil temperature detection unit 45 thereof.

The temperature sensor 42 for the motor is provided at a predetermined position in each motor 6, for example, in the stator 6b (FIG. 2), and the motor temperature detection unit 43 measures a measured value including a voltage measured by the temperature sensor 42 as a temperature. Convert to. The temperature sensor 34 for the inverter is provided in any one of the plurality of switching elements in each inverter 31, and the switching element temperature detection unit 39 converts the measured value including the voltage measured by the temperature sensor 34 into the temperature. Convert. The oil temperature sensor 44 is provided in the oil storage unit Tk (FIG. 2) of the speed reducer 7 (FIG. 2), and the oil temperature detection unit 45 measures a measured value including a voltage measured by the oil temperature sensor 44. Convert to temperature.

As the temperature sensors 42 and 34 and the oil temperature sensor 44, for example, a diode for temperature sensing or a thermistor may be applied. As the motor temperature detection unit 43, the switching element temperature detection unit 39, and the oil temperature detection unit 45, for example, a means for linearizing the measured value, an insulator between high voltage and low voltage, an amplifier for voltage amplification, and the like. A filter circuit, an AD converter and the like are included.

The overheated torque distribution changing unit 40 enables the one motor 6 to be output to the maximum torque when any of the motor temperature, the switching element temperature and the oil temperature among the detected temperatures on the one motor side is equal to or less than the first threshold value. , When the value exceeds the first threshold value and is equal to or less than the second threshold value larger than the first threshold value, the maximum torque (torque limit value) that can be output by the one motor 6 is lowered as the detection temperature rises. I do. When any of the motor temperature, the switching element temperature, and the oil temperature of the detected temperatures on the one motor side exceeds the second threshold value, the overheated torque distribution changing unit 40 reduces the torque of the one motor 6 to zero. Restrict.

The overheated torque distribution changing unit 40 is the maximum torque that can be output by the other motor 6 according to the torque limit of the one motor 6 even when the detected temperature on the other motor side does not exceed the first threshold value. When torque is limited to lower (torque limit value) and the detected temperature on one motor side exceeds the second threshold value, the ratio α (determined to the maximum torque that can be output by the other motor 6) Set to the torque limit value set in 0 to 1).

The maximum torque referred to here may be the maximum torque obtained from the so-called NT curve curve (maximum output curve), which is a characteristic of the rotation speed and output torque of the motor, as shown in FIG. 7, or the motor. It may be its own maximum torque. As shown in FIG. 3, the overheated torque distribution changing unit 40 sets the value obtained by multiplying the maximum torque by the ratio α as the torque limit value.

Since the oil temperature, the stator of the motor 6, and the allowable temperature of the switching element are different, a first threshold value and a second threshold value are set for each temperature. The first and second threshold values in each detection target are determined by, for example, the heat-resistant temperature of the constituent parts and one or both of the test and the simulation. However, in each detection target, the second threshold value is set larger than the first threshold value.
Further, in the motor 6, the inverter 31, and the reduction unit Tk (FIG. 2) for driving the same drive wheels, a plurality of temperatures of the motor temperature, the switching element temperature, and the oil temperature simultaneously exceed the first threshold value. If so, the overheated torque distribution changing unit 40 adopts the lowest torque limit value and limits the torque of the drive wheel motor 6 at this torque limit value.

FIG. 4 is a diagram showing an example when overheating occurs on the left wheel side. Hereinafter, FIG. 3 will be described with reference to the appropriate reference. When overheating occurs in any of the motor 6, the inverter 31, and the storage section on the left wheel side, the overheating torque distribution changing section 40 determines the torque limit value of the left and right wheels when the overheated detection target exceeds the first threshold value. When the second threshold value is exceeded, the torque limit value on the left wheel side is set to zero, and the torque limit value on the right wheel side is set to the value obtained by multiplying the maximum torque by the ratio α. By this method, it is prevented that the torque difference between the left and right wheels becomes excessive due to overheating.

As shown in FIG. 3, the overheated torque distribution changing unit 40 is obtained on the left and right according to the detection temperature of the temperature detecting means Ks on one motor side when the detected temperatures on both motor sides both exceed the first threshold value. Of the torque limit value of the drive wheels of 1 and the torque limit value of the left and right drive wheels obtained according to the detection temperature of the temperature detecting means Ks on the other motor side, the torque limit value of both motors 6 and 6 is the lower torque limit value. I do. As a specific example, FIG. 5 shows an example in which overheating occurs on both the left and right wheels.

As shown in FIGS. 3 and 5, when overheating occurs in any of the motor 6, the inverter 31, and the storage section on the left wheel side, and any of the motor 6, the inverter 31, and the storage section on the right wheel side. The torque limit value A on the left wheel side (FIG. 5 (a)) obtained according to the detected temperature on the left wheel side is larger than the torque limit value A'(FIG. 5 (b)) on the left wheel side obtained according to the detected temperature on the right wheel side. Since it is small (A <A'), A is adopted as the torque limit value on the left wheel side. At the same time, the torque limit value B'(FIG. 5 (b)) on the right wheel side obtained according to the detected temperature on the right wheel side is the torque limit value B'(FIG. 5 (b)) on the right wheel side obtained according to the detected temperature on the left wheel side. Since it is smaller than a)) (B> B'), B'is adopted as the torque limit value on the right wheel side.

<Ratio α setting example>
As shown in FIGS. 3 and 6A, the torque distribution changing unit 40 at the time of overheating may keep the ratio α constant regardless of the vehicle speed. In this case, the software of the drive control device 16 can be simplified, and the cost can be reduced. If the ratio α is set to “1”, the maximum torque can be output without being affected by the overheating of the opposite wheel. If the ratio α is set to “0”, the same torque limit value can be set for both wheels due to overheating of the opposite wheels.

As shown in FIGS. 3 and 6 (b) to 6 (d), the overheated torque distribution changing unit 40 may change the ratio α depending on the vehicle speed. For example, the ratio α may be set to be larger as the vehicle speed is lower, and the ratio α may be set to be smaller as the vehicle speed is higher. In the drive control device 16, for example, a speed sensor 35 that detects the rotation speed of the drive wheels, and a vehicle speed detecting means 41 that obtains the vehicle speed according to a calculation formula or a map determined from the rotation speed detected by the speed sensor 35. The ratio α can be changed from the vehicle speed obtained by the vehicle speed detecting means 41. In this case, the drive wheel on the side opposite to the drive wheel in which the abnormality has occurred can output the maximum output or a value close to the maximum output at low speed, the output can be limited at high speed, and an unintended excessive torque difference does not occur between the left and right wheels. In the case of a four-wheel independent drive vehicle, the torque distributed to one drive wheel is smaller than that of a two-wheel drive vehicle having the same total driving force, so the ratio α can be set larger.

<Effect>
According to the drive control device 16 described above, when the detection temperature on one motor side exceeds the first threshold value and the torque is limited to lower the maximum torque that can be output by the one motor 6, the one motor According to the torque limit of 6, the torque limit that lowers the maximum torque that can be output by the other motor 6 is performed. Therefore, it is possible to prevent the torque difference between the left and right drive wheels from becoming too large and the behavior of the vehicle from becoming unstable. When the detected temperature on one motor side exceeds the second threshold value, the minimum driving force is set to the torque limit value set at a specified ratio to the maximum torque that can be output by the other motor 6. Can be secured. As a result, a provisional evacuation run can be performed. By limiting the torque in this way, it is possible to suppress the overload of the motor 6 and stabilize the behavior of the vehicle.

<About other embodiments>
In the following description, the same reference numerals will be given to the parts corresponding to the matters described in advance in each embodiment, and duplicate description will be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described above unless otherwise specified. It has the same effect from the same configuration. In addition to the combination of the parts specifically described in each embodiment, it is also possible to partially combine the embodiments as long as the combination does not cause any trouble.

As shown in FIG. 3, the drive control device 16 is provided with a steering angle detecting means Dk for determining whether or not the vehicle is turning, and the overheated torque distribution means 40 is used to turn the vehicle by the steering angle detecting means Dk. The torque of each motor 6 may be limited only when it is determined to be inside. As the steering angle detecting means Dk, for example, a steering angle sensor that acquires a steering angle of a steering wheel or the like (not shown) can be applied.

In the configuration provided with the steering angle detecting means Dk, the overheated torque distributing means 40 drives the drive wheels on the side where the detection temperature does not exceed the first threshold value when the steering angle detecting means Dk determines that the vehicle is traveling straight. May be able to output up to the maximum torque of the motor 6. In this case, by increasing the driving force of the vehicle while the vehicle is traveling straight, the vehicle can travel on its own on a steep uphill road or the like.

In the configuration provided with the steering angle detecting means Dk, the overheated torque distributing means 40 sets the ratio α to the maximum “1” when the steering angle detecting means Dk determines that the vehicle is traveling straight, and the steering angle detecting means Dk The ratio α may be reduced as the degree of turning of the vehicle increases. By changing the ratio α according to the degree of turning of the vehicle in this way, the behavior of the vehicle during turning can be more reliably stabilized.

In the in-wheel motor drive device, a cycloid type speed reducer, a planetary speed reducer, a two-axis parallel speed reducer, and other speed reducers can be applied.
In the above-described embodiment, an example in which the drive control device is applied to an electric vehicle provided with an in-wheel motor drive device has been described. However, as shown in FIG. 8, two motors 6 and 6 and each motor are attached to the vehicle body 1. A drive control device may be provided in a two-motor on-board type vehicle in which speed reducers 7 and 7 corresponding to 6 are provided and the wheels 3 and 3 which are the left and right drive wheels are driven by these motors 6 and 6.

In FIGS. 1 and 8, the left and right drive wheels driven by the motor 6 may be either front or rear wheels. It may also be a four-wheel drive. The motor 6 may be a direct motor that drives the drive wheels without interposing a speed reducer.

Although the embodiments for carrying out the present invention have been described above based on the embodiments, the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

2 ... Wheels (driving wheels), 4 ... Wheel bearings, 6 ... Motors, 7 ... Reducers, 16 ... Drive control devices, 31 ... Inverters, 40 ... Overheated torque distribution changing unit (torque limiting means), 34, 42 ... Temperature sensor, Dk ... Steering angle detecting means, Ks ... Temperature detecting means, IWM ... In-wheel motor drive device

Claims (10)

A drive control device that controls the motors of a vehicle in which the left and right drive wheels can be driven independently by individual motors.
A temperature detecting means for detecting the motor temperature of each of the motors or the temperature of a portion that affects the change in the motor temperature, and
A torque limiting means for limiting the torque of each of the motors based on the detected temperature detected by the temperature detecting means is provided.
This torque limiting means
When the detection temperature on one motor side detected by the temperature detecting means is equal to or lower than the first threshold value, the one motor can be output up to the maximum torque.
When the detection temperature on the one motor side exceeds the first threshold value and is equal to or lower than the second threshold value larger than the first threshold value, the maximum torque that can be output by the one motor as the detection temperature rises. Perform torque limit to lower
When the detection temperature on the one motor side exceeds the second threshold value, the torque of the one motor is limited to zero.
Even if the detected temperature on the other motor side does not exceed the first threshold value, the torque limit that lowers the maximum torque that can be output by the other motor is performed according to the torque limit of the one motor, and the one motor A drive control device that sets a torque limit value set at a predetermined ratio to the maximum torque that can be output by the other motor when the detected temperature on the side exceeds the second threshold value. The drive control device according to claim 1 includes an inverter that converts DC power into AC power used to drive the motor by opening and closing a plurality of switching elements.
The temperature detecting means is at least one of a temperature sensor for a motor that detects the motor temperature of each motor, a temperature sensor for an inverter that detects the temperature of each inverter, and an oil temperature sensor for lubrication or cooling. Have two
In the torque limiting means, the first is that the detection temperature detected by a plurality of temperature sensors that detect at least two temperatures of the motor for driving the same drive wheel, its inverter, and oil corresponds to each other. A drive control device that limits the torque of the motor with the smallest torque limit value obtained for each temperature sensor when the threshold value of is exceeded. In the drive control device according to claim 1 or 2, the torque limiting means means that when the detection temperatures of both motors both exceed the first threshold value, the detection temperature of the temperature detecting means on one motor side. Of the torque limit values of the left and right drive wheels obtained according to the above and the torque limit values of the left and right drive wheels obtained according to the detection temperature of the temperature detecting means on the other motor side, both motors have the lower torque limit value. Drive control device that limits the torque of. In the drive control device according to any one of claims 1 to 3, the torque limiting means is a drive control device that changes the predetermined ratio according to the vehicle speed. In the drive control device according to claim 4, the torque limiting means sets the predetermined ratio to be larger as the vehicle speed is lower, and is set to be smaller as the vehicle speed is higher. apparatus. In the drive control device according to any one of claims 1 to 3, the torque limiting means is a drive control device that keeps the predetermined ratio constant regardless of the vehicle speed. The drive control device according to any one of claims 1 to 3, has a steering angle detecting means for determining whether or not the vehicle is turning, and the torque limiting means is the steering angle. A drive control device that limits the torque of each of the motors only when the detection means determines that the vehicle is turning. In the drive control device according to claim 7, the torque limiting means enables the drive wheels on the side where the detected temperature does not exceed the first threshold value to output up to the maximum torque of the motor while the vehicle is traveling straight. Drive control device. In the drive control device according to any one of claims 1 to 3, the torque limiting means sets the predetermined ratio α to "1" while the vehicle is traveling straight, and the vehicle is driven by the steering angle detecting means. A drive control device that reduces the predetermined ratio α as the degree of turning of the vehicle increases. In the drive control device according to any one of claims 1 to 9, the motor is a motor, a wheel bearing that supports the drive wheels, and a wheel bearing that reduces the rotation of the motor. A drive control device that constitutes an in-wheel motor drive device including a speed reducer that transmits to bearings.

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