JP2018046742A - In-wheel motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-wheel motor drive device which concurrently detects temperature of a lubrication oil and temperature of a motor coil and accurately detects abnormality in an entire output range of a motor.SOLUTION: An in-wheel motor drive device includes an electric motor 1, a wheel bearing 5, a speed reducer 2, a lubrication oil supply mechanism, and a control unit U1. The lubrication oil supply mechanism includes a supply oil passage and a pump. An oil temperature sensor Sb is provided at a lubrication oil passage of the speed reducer 2 and a temperature sensor Sa is provided at a motor stator. The control unit U1 includes motor output limiting means 95 which limits current of the electric motor 1 when one of or both of temperature detected by the oil temperature sensor Sb and temperature detected by the temperature sensor Sa exceed set threshold values, respectively.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an in-wheel motor drive device, and relates to a technique for accurately detecting an abnormality of the in-wheel motor drive device using a coil temperature sensor and an oil temperature sensor.

The in-wheel motor drive device includes a speed reducer, a motor, and a wheel bearing. The loss of the in-wheel motor drive device is a loss obtained by adding the losses of the respective parts. The loss of the reducer is mainly due to the rolling resistance of the bearing part and the sliding resistance of the sliding part. In both cases, if the bearing specifications and the clearance inside the reducer are determined, the loss depends on the rotational speed. (FIG. 7).
Motor loss is mainly iron loss, copper loss and mechanical loss. Copper loss depends on the coil current, iron loss depends on the coil current and the rotational speed, and mechanical loss depends on the rotational speed. Therefore, in the loss in the low speed and high torque region, the copper loss occupies most of the loss, and in the high speed and low torque region, the iron loss and the reduction gear loss occupy most of the loss (FIG. 8).

  Therefore, as shown in FIG. 9, the combined unit loss map can be divided into a region A in which losses due to the motor occupy and a region C in which losses due to both the motor and the speed reducer occupy. Region B is a region where the loss of the speed reducer and the motor is small and abnormality detection is not necessary.

  The loss in the low-speed high-torque region shown as region A is mainly due to the copper loss due to the motor. Therefore, the degree of increase in the coil temperature is larger than the degree of increase in the temperature of the lubricating oil. Response delay occurs. On the other hand, in the high-speed low-torque region shown as region C, since the motor iron loss and the reduction gear loss occupy most of the region, the increase in the lubricating oil temperature is larger than the increase in the coil temperature.

  Further, the coil temperature sensor is disposed between the slots of the stator and is difficult to apply the lubricating oil, and it is difficult to directly measure the temperature of the lubricating oil. The temperature of the coil and the stator is increased by the lubricating oil splashed on the coil and the stator core, and the coil temperature sensor reacts to the coil temperature increased by the heat conduction and heat transfer. The response is greatly delayed.

Japanese Patent Application Laid-Open No. 2012-178917

  In detecting an abnormality of a unit, temperature is considered as a detection target, and the item may be a coil or lubricating oil. The coil temperature is arranged between the slots of the stator in order to avoid the influence of the lubricating oil, and the lubricating oil is hardly applied. In addition, the detection of the lubricating oil temperature is indispensable in order to accurately detect the abnormality of the speed reducer, and it is difficult to estimate the coil temperature of the motor.

  Conventionally, regarding a reduction gear of an in-wheel motor drive device, it has been proposed to arrange a temperature sensor for lubricating oil at the most downstream side of the lubricating path (Japanese Patent Application No. 2013-198131). Detecting abnormalities in the entire output area of the in-wheel motor using only the oil temperature sensor means that there is a large delay in the response of the lubricating oil temperature to the coil temperature in the low-speed, high-torque region, and that the unit abnormalities are detected accurately. Is difficult. When the coil temperature rises and exceeds the heat resistance temperature of the coil due to the response delay, there is a risk of overloading the motor.

  As another conventional example, for the motor part of the in-wheel motor drive device, the motor coil temperature is detected, the differential value of the coil temperature change is calculated, and when this differential value exceeds a certain threshold, it is determined as abnormal. The output is controlled. With only the coil temperature, the response of the output of the coil temperature measurement sensor is delayed with respect to the lubricating oil in the high-speed and low-torque region, and it is difficult to accurately detect the abnormality of the unit. Due to the response delay, the lubricating oil temperature rises. For example, when the heat resistance temperature of the resin member constituting the speed reducer is exceeded, the speed reducer may be abnormal.

  An object of the present invention is to provide an in-wheel motor drive device that can detect the temperature of the lubricating oil and the temperature of the motor coil at the same time, and can detect an abnormality with high accuracy throughout the output range of the motor. Is to provide.

The in-wheel motor drive device according to the present invention includes an electric motor 1 for driving a wheel, a wheel bearing 5 for rotating and supporting the wheel, and a deceleration for reducing the rotation of the electric motor 1 and transmitting it to the wheel bearing 5. An in-wheel motor drive device including a machine 2, a lubricant supply mechanism Jk that supplies lubricant to the speed reducer 2, and a controller U <b> 1 that controls the electric motor 1,
The lubricating oil supply mechanism Jk has a supply oil passage 30 for supplying lubricating oil to the speed reducer 2, and a pump 28 for supplying lubricating oil to the speed reducer 2.
An oil temperature sensor Sb for detecting the temperature of the lubricating oil is provided in the lubricating oil passage 29 of the speed reducer 2, and a temperature sensor Sa for detecting the temperature of the motor coil 78 is provided in the stator 9 of the electric motor 1,
When one or both of the temperature detected by the oil temperature sensor Sb and the temperature detected by the temperature sensor Sa exceed a predetermined threshold, the control device U1 A motor output limiting means 95 for limiting the current is provided.
The “predetermined threshold value” is determined by, for example, experiments or simulations.
Limiting the current of the electric motor includes setting the current of the electric motor to “zero”.

According to this configuration, the oil temperature sensor Sb provided in the lubricating oil passage 29 of the speed reducer 2 detects the temperature of the lubricating oil constantly or periodically. A temperature sensor Sa provided in the stator 9 detects the temperature of the motor coil 78 at all times or regularly. The motor output limiting means 95 of the control device U1 determines whether one or both of the temperature detected by the oil temperature sensor Sb and the coil temperature detected by the temperature sensor Sa exceed a predetermined threshold value. judge. When it is determined that the threshold value has been exceeded, the motor output limiting means 95 limits the current of the electric motor 1.
The heat generated by the loss of the in-wheel motor drive device is mostly due to the copper loss due to the motor in the low speed and high torque region. Therefore, the oil temperature sensor Sb can detect oil temperature relative to the coil temperature only by detecting the temperature of the lubricating oil. Although there is a possibility that a response delay of temperature may occur, in order to limit the current of the electric motor 1 using the coil temperature detected by the temperature sensor Sa, the response delay of the temperature with respect to the coil temperature is eliminated and precise abnormality detection is performed. Can do.
In the high-speed and low-torque region, the motor iron loss and the reduction gear loss account for the majority, so just detecting the coil temperature with the temperature sensor Sa will increase the temperature of the lubricating oil that cools the reduction gear. There is a possibility that the response speed is delayed and the reduction gear temperature rises. However, since the current of the electric motor 1 is limited using the oil temperature detected by the oil temperature sensor Sb, the response delay to the lubricating oil temperature is eliminated. It is possible to prevent the speed reducer 2 from being abnormal.
In this way, an increase in the coil temperature of the electric motor 1 can be suppressed to prevent the electric motor 1 from being overloaded, and an increase in the temperature of the lubricating oil can be suppressed to prevent the speed reducer 2 from becoming abnormal. be able to. Therefore, the abnormality can be detected with high accuracy in the entire range from the low speed high torque region to the high speed low torque region in the output range of the electric motor 1.

Each threshold value of the oil temperature sensor Sb and the temperature sensor Sa includes a first threshold value and a second threshold value greater than the first threshold value,
The motor output limiting means 95 starts the output limitation to the electric motor 1 when the first threshold value is exceeded in any threshold value, and when the second threshold value is exceeded, the motor output limiting means 95 outputs the current of the electric motor 1. It may be zero.
The first and second threshold values are determined by, for example, experiments or simulations.
By thus limiting the output to the electric motor 1 in stages, the vehicle can be smoothly operated without causing the driver to feel a sudden discomfort with respect to the driver's accelerator operation.

The motor output limiting means 95 may decrease the torque command value input to the electric motor 1 at a constant rate determined with respect to the temperature when the first threshold value is exceeded.
The predetermined ratio is appropriately determined by, for example, experimentation or simulation.
Thus, by decreasing the torque command value at a constant rate, it is possible to prevent the torque command value for the accelerator operation from changing sharply.

  The motor output restriction means 95 may release the restriction on the output to the electric motor 1 when the first and second threshold values are exceeded and then falls below the first threshold value after a certain time. The predetermined time is determined by a test or simulation. By canceling the output restriction to the electric motor 1 under such conditions, that is, by inputting all the accelerator command values, it is possible to restore the motor torque and perform the operation according to the driver's will.

The pump 28 may be disposed on the same axis between the electric motor 1 and the speed reducer 2.
The pump 28 may be provided outside an in-wheel motor unit including the electric motor 1, the wheel bearing 5, and the speed reducer 2. In this case, for example, the lubricating oil tank in the apparatus main body can be omitted, and the oil passage to be provided in the apparatus main body can be reduced. Thereby, the apparatus main body can be made compact. Therefore, the in-wheel motor drive device can be mounted on various vehicles, and versatility can be improved.

An in-wheel motor drive device according to the present invention includes an electric motor that drives a wheel, a wheel bearing that rotatably supports the wheel, a speed reducer that decelerates the rotation of the electric motor and transmits the rotation to the wheel bearing, In an in-wheel motor drive device comprising a lubricant supply mechanism for supplying lubricant to a reduction gear and a control device for controlling the electric motor,
The lubricating oil supply mechanism has a supply oil path for supplying lubricating oil to the speed reducer and a pump for supplying lubricating oil to the speed reducer, and the temperature of the lubricating oil is set in the lubricating oil path of the speed reducer. An oil temperature sensor for detecting is provided, and a temperature sensor for detecting the temperature of the motor coil is provided for the stator of the electric motor, and the control device detects the temperature detected by the oil temperature sensor and the temperature sensor. In the in-wheel motor drive device, the temperature of the lubricating oil, the motor coil, and the motor output limiting means for limiting the current of the electric motor when either or both of the temperatures exceed a predetermined threshold value. The temperature can be detected at the same time, and the abnormality can be accurately detected over the entire output range of the motor.

It is sectional drawing of the in-wheel motor drive device which concerns on 1st Embodiment of this invention. It is sectional drawing of the reduction gear part used as the II-II line cross section of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is a block diagram of a control system of the in-wheel motor drive device. It is a figure which shows the relationship between the threshold value of a temperature, and a motor input. It is sectional drawing of the in-wheel motor drive device which concerns on other embodiment of this invention. It is a figure which shows the representative example of the loss map of a reduction gear. It is a figure which shows the typical example of the loss map of a motor. It is a figure which shows the typical example of the loss map of a unit.

  An in-wheel motor drive device according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, this in-wheel motor drive device includes an electric motor 1 that drives wheels, a speed reducer 2 that decelerates the rotation of the electric motor 1, and an input shaft 3 (speed reducer input) of the speed reducer 2. It has a wheel bearing 5 rotated by an output member 4 coaxial with the shaft 3), a lubricating oil supply mechanism Jk, and a control device U1 (FIG. 4). A reduction gear 2 is interposed between the wheel bearing 5 and the electric motor 1, a wheel hub as a driving wheel supported by the wheel bearing 5, a motor rotating shaft 6 of the electric motor 1, and a reduction gear input shaft 3. And the output member 4 are connected on the same axis.

  A suspension (not shown) in the vehicle is connected to the reduction gear housing 7 that houses the reduction gear 2. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle with the in-wheel motor drive device provided in the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side. .

  The electric motor 1 is a radial gap type IPM motor (so-called embedded magnet type synchronous motor) in which a radial gap is provided between a motor stator 9 fixed to a motor housing 8 and a motor rotor 10 attached to the motor rotating shaft 6. . The motor housing 8 is provided with bearings 11 and 12 which are separated from each other in the axial direction, and the motor rotating shaft 6 is rotatably supported by the bearings 11 and 12.

The motor rotating shaft 6 transmits the driving force of the electric motor 1 to the speed reducer 2. A flange portion 6 a extending radially outward is provided near the middle portion in the axial direction of the motor rotating shaft 6. A rotor fixing member 13 is provided on the flange portion 6 a, and the motor rotor 10 is attached to the rotor fixing member 13. Yes.
The motor stator 9 of the electric motor 1 is provided with a temperature sensor Sa that detects the temperature of the motor coil 78. For example, a thermistor is applied as the temperature sensor Sa. The temperature detected by the temperature sensor Sa is used for control for limiting the current of the electric motor 1 as described later.

  The reduction gear input shaft 3 has one end in the axial direction extending into the motor rotation shaft 6 and is splined to the motor rotation shaft 6. A bearing 14a is fitted in the cup portion 4a of the output member 4, and a bearing 14b is fitted in a cylindrical connecting member 26 connected to the cup portion 4a via an inner pin 22. The reduction gear input shaft 3 is rotatably supported by bearings 14a, 14b, 11, and 12. Eccentric portions 15 and 16 are provided on the outer peripheral surface of the speed reducer input shaft 3 in the speed reducer housing 7. These eccentric portions 15 and 16 are provided with a 180 ° phase shift so that the centrifugal force due to the eccentric motion is canceled out from each other.

The reducer 2 is a cycloid reducer having an outer pin housing Ih, a reducer input shaft 3, curved plates 17 and 18, a plurality of outer pins 19, inner pins 22, and a counterweight 21.
2 is a cross-sectional view of the speed reducer portion taken along the line II-II in FIG. In the speed reducer 2, two curved plates 17 and 18 formed with wavy trochoid curves having a gentle outer shape are attached to the eccentric portions 15 and 16 via bearings 85, respectively. A plurality of outer pins 19 for guiding the eccentric movements of the curved plates 17 and 18 on the outer peripheral side are provided on the outer pin housing Ih on the inner side of the reducer housing 7, respectively, and are attached to the cup portion 4a (FIG. 1). The inner pin 22 is engaged with a plurality of circular through holes 89 provided in the curved plates 17 and 18 in an inserted state.

  As shown in an enlarged view in FIG. 3, needle roller bearings 92 and 93 are attached to each outer pin 19 and each inner pin 22. Each outer pin 19 is supported at both ends by needle roller bearings 92 and is in rolling contact with the outer peripheral surface of each curved plate 17, 18. Further, in each inner pin 22, the outer ring 93 a of the needle roller bearing 93 is in rolling contact with the inner periphery of each through-hole 89 of each curved plate 17, 18. Therefore, the contact resistance between the outer pin 19 and the outer periphery of each curved plate 17, 18 and the contact resistance between each inner pin 22 and the inner periphery of each through hole 89 are reduced.

  Therefore, as shown in FIG. 1, the eccentric motions of the curved plates 17 and 18 can be smoothly transmitted to the inner member 5a of the wheel bearing 5 as a rotational motion. That is, when the motor rotating shaft 6 rotates, the curved plates 17 and 18 provided on the speed reducer input shaft 3 rotating integrally with the motor rotating shaft 6 perform an eccentric motion. At this time, the outer pin 19 is engaged so as to be in rolling contact with the outer peripheral surfaces of the curved plates 17 and 18 that are eccentrically moved, and the curved plates 17 and 18 are connected to the inner pin 22 and the through hole 89 (FIG. 3). Due to the engagement, only the rotational motion of the curved plates 17 and 18 is transmitted to the output member 4 and the inner member 5a as rotational motion. The rotation of the inner member 5a is decelerated with respect to the rotation of the motor rotating shaft 6.

  The lubricating oil supply mechanism Jk is an axial oil supply mechanism that supplies lubricating oil used for both the lubrication of the speed reducer 2 and the cooling of the electric motor 1 from the inside of the motor rotating shaft 6. The lubricating oil supply mechanism Jk includes a lubricating oil passage 29, a supply oil passage 30, a discharge oil passage 38, and a pump 28. The lubricating oil path 29 is a lubricating oil path 29 in the speed reducer housing 7 in the speed reducer 2, and the lubricating oil path 29 includes a lubricating oil tank 29a. The lubricating oil tank 29 a is provided at the lower portion of the speed reducer housing 7, stores lubricating oil, and communicates with the lower portion of the motor housing 8.

  The supply oil passage 30 supplies lubricating oil to the electric motor 1 and the speed reducer 2 from the lubricating oil tank 29a. The supply oil passage 30 includes a suction-side oil passage 30a, a discharge-side oil passage 30b, a housing outer peripheral-side oil passage 30c, a communication passage 30d, a motor rotation shaft oil passage 30e, and a reduction gear oil passage 30f. The suction-side oil passage 30 a communicates with the suction port in the lubricating oil tank 29 a and the suction port of the pump 28, and includes a lower portion of the speed reducer housing 7 and a lower portion of the motor housing 8. The discharge-side oil passage 30 b communicates with the discharge port of the pump 28 and extends substantially radially outward in the motor housing 8.

  The housing outer peripheral side oil passage 30 c communicates with the discharge side oil passage 30 b and extends along the axial direction from the outboard side to the inboard side in the motor housing 8. The communication passage 30d is formed at the inboard side end of the motor housing 8, the inlet of the communication passage 30d communicates with the housing outer peripheral oil passage 30c, and the outlet of the communication passage 30d communicates with the motor rotating shaft oil passage 30e. Communicate.

  The motor rotation shaft oil passage 30 e is provided along the axis in the motor rotation shaft 6. Part of the lubricating oil guided from the communication passage 30d to the motor rotation shaft oil passage 30e is formed inside the rotor fixing member 13 via a through hole extending radially outward of the motor rotation shaft 6 and the flange portion 6a. The motor rotor 10 is cooled by passing through the oil passage extending radially outward. Further, the coil 78 is cooled by injecting lubricating oil from the oil outlet of the oil passage to the inner peripheral surface of each coil end by the centrifugal force of the motor rotor 10 and the pressure of the pump 28.

The speed reducer oil passage 30 f is provided in the speed reducer 2 and supplies lubricating oil to the speed reducer 2. The speed reducer oil passage 30 f includes an input shaft oil passage 36 and an oil supply port 37. The input shaft oil passage 36 communicates with the motor rotation shaft oil passage 30e and extends in the axial direction from the inboard side end inside the reduction gear input shaft 3 to the outboard side. The oil supply port 37 extends radially outward from the axial position where the eccentric portions 15 and 16 are provided in the input shaft oil passage 36.
The reduction gear housing 7 is provided with a discharge oil passage 38 for discharging the lubricating oil used for lubricating the reduction gear 2 to the lubricating oil tank 29a.

  The pump 28 sucks up the lubricating oil stored in the lubricating oil tank 29a from the suction port in the lubricating oil tank 29a via the suction side oil passage 30a, and sequentially discharges the oil passage 30b and the housing outer periphery side oil passage 30c. Then, it is circulated through the communication passage 30d to the motor rotation shaft oil passage 30e and the reduction gear oil passage 30f. The pump 28 is disposed on the same axis between the electric motor 1 and the speed reducer 2, for example, an inner rotor (not shown) that is rotated by the rotation of the output member 4, and a follower that is driven by the rotation of the inner rotor. A cycloid pump having a rotating outer rotor, a pump chamber, a suction port, and a discharge port (all not shown).

  When the inner rotor is rotated by the rotation of the output member 4 driven by the electric motor 1, the outer rotor is driven to rotate. At this time, the inner rotor and the outer rotor rotate about different rotation centers, so that the volume of the pump chamber changes continuously. Thereby, the lubricating oil stored in the lubricating oil tank 29a is sucked up from the suction port via the suction side oil passage 30a and flows in from the suction port, and from the discharge port to the discharge side oil passage 30b, the housing outer peripheral side. The oil is sequentially sent to the oil passage 30c and the communication passage 30d.

  The lubricating oil is guided from the communication passage 30d to the motor rotation shaft oil passage 30e. Part of the lubricating oil cools the motor rotor 10 and the coil 78 as described above, and then moves below the motor housing 8 due to gravity and flows into the lubricating oil tank 29 a communicating with the lower portion of the motor housing 8.

  Lubricating oil guided to the oil supply port 37 from the motor rotation shaft oil passage 30 e via the input shaft oil passage 36 is discharged from the outer diameter side opening end of the oil supply port 37. Due to the centrifugal force and the pressure of the pump 28 acting on the lubricating oil, the lubricating oil moves radially outward in the speed reducer housing 7 while lubricating each part in the speed reducer 2. Thereafter, the lubricating oil moves downward by gravity and is stored in the lubricating oil tank 29a from the oil discharge port 38. The lubricating oil tank 29a is provided with an oil temperature sensor Sb that detects the temperature of the lubricating oil. For example, a thermistor is applied as the oil temperature sensor Sb. The temperature detected by the oil temperature sensor Sb is used for control for limiting the current of the electric motor 1 as described later.

The control system will be described.
FIG. 4 is a block diagram of a control system of the in-wheel motor drive device.
The control device U1 includes an ECU 43 that is an electric control unit that performs overall control of the automobile, and an inverter device 44 that controls the electric motor 1 for traveling in accordance with a command to the ECU 43. The inverter device 44 includes a power circuit unit 45 provided for each electric motor 1 and a motor control unit 46 that controls the power circuit unit 45. The motor control unit 46 has a function of outputting information such as detection values and control values relating to the in-wheel motor drive device of the motor control unit 46 to the ECU 43.

  The power circuit unit 45 includes an inverter 45a that converts the DC power of the battery 47 into three-phase AC power used to drive the electric motor 1, and a PWM driver 45b that controls the inverter 45a. The inverter 45a is composed of a plurality of semiconductor switching elements (not shown), and the PWM driver 45b performs pulse width modulation on the input current command and gives an on / off command to each of the semiconductor switching elements.

  The motor control unit 46 includes a computer, a program executed on the computer, and an electronic circuit, and includes a motor drive control unit 48 as a basic control unit. The motor drive control unit 48 is a unit that converts the current command into a current command in accordance with an acceleration / deceleration command by a torque command or the like given from the ECU 43 that is a host control unit, and gives a current command to the PWM driver 45b. The motor drive control unit 48 obtains a motor current flowing from the inverter 45a to the electric motor 1 from the current detection means 35, and performs current feedback control. The motor drive control unit 48 obtains the rotation angle of the motor rotor of the electric motor 1 from the angle sensor 49 and performs vector control.

  The motor control unit 46 is provided with motor output limiting means 95, abnormality report means 41, and storage means 50. The motor output limiting means 95 is a coil temperature detected by a temperature sensor Sa that detects a temperature detected by the oil temperature sensor Sb (referred to as “oil temperature”) and a temperature of the motor coil (referred to as “coil temperature”). When either or both of these exceed a predetermined threshold value, the current of the electric motor 1 is limited. The motor output limiting unit 95 includes a determination unit 39 and a control unit 40.

  The determination unit 39 always determines whether or not the oil temperature and the coil temperature exceed the predetermined threshold values. The threshold value of the oil temperature is determined based on, for example, the relationship between the oil temperature and the viscosity of the lubricating oil, the relationship between the viscosity of the lubricating oil and the rotational resistance of the electric motor 1 and the like by experiments and simulations. The threshold value of the coil temperature is determined as appropriate based on, for example, the relationship between the coil temperature and time that causes insulation in the motor coil, through experiments and simulations.

Each threshold value is stored in the storage unit 50 so as to be rewritable. In this example, each threshold value of the oil temperature sensor Sb and the temperature sensor Sa includes a first threshold value and a second threshold value that is larger than the first threshold value.
If it is determined that either one of the detected oil temperature and coil temperature exceeds a predetermined threshold value, the control unit 40 causes the motor drive control unit 48 to reduce the current of the electric motor 1. To the power circuit unit 45.

  FIG. 5 is a diagram showing the relationship between the coil temperature threshold and the motor input. Although not shown, the relationship between the oil temperature threshold and the motor input has the same relationship as in FIG. This will be described with reference to FIG. The control unit 40 starts limiting the output to the electric motor 1 when the first threshold value in any one of the threshold values is exceeded. Specifically, the control unit 40 outputs a torque command value to be input to the electric motor 1 at a constant rate (a constant inclination) determined with respect to the temperature when the first threshold value in any threshold value is exceeded. The power circuit unit 45 is commanded via the motor drive control unit 48 so as to decrease the power circuit unit.

  The control unit 40 instructs the power circuit unit 45 via the motor drive control unit 48 to set the current of the electric motor 1 to zero when the second threshold value in any one of the threshold values is exceeded. In addition, after exceeding the first and second thresholds, the control unit 40 releases the restriction on the output to the electric motor 1 when it falls below the first threshold after a certain time.

  As shown in FIG. 4, the abnormality reporting unit 41 outputs abnormality occurrence information to the ECU 43 when the determination unit 39 determines that the first threshold value of any one of the threshold values has been exceeded. The abnormality display means 42 provided in the ECU 43 receives the abnormality occurrence information output from the abnormality report means 41 and causes the display device 27 such as a console panel of the vehicle to perform a display notifying the abnormality.

The effect will be described.
The determination unit 39 in the motor output limiting means 95 determines whether one or both of the detected oil temperature and coil temperature exceeds a predetermined threshold value. When it is determined that the threshold value has been exceeded, the control unit 40 commands the power circuit unit 45 via the motor drive control unit 48 so as to decrease the torque command value input to the electric motor 1.
The heat generated by the loss of the in-wheel motor drive device is mostly due to the copper loss due to the motor in the low speed and high torque region. Therefore, the oil temperature sensor Sb can detect oil temperature relative to the coil temperature only by detecting the temperature of the lubricating oil. Although there is a possibility that a response delay of temperature may occur, in order to limit the current of the electric motor 1 using the coil temperature detected by the temperature sensor Sa, the response delay of the temperature with respect to the coil temperature is eliminated and precise abnormality detection is performed. Can do.
In the high-speed and low-torque region, the motor iron loss and the reduction gear loss account for the majority, so just detecting the coil temperature with the temperature sensor Sa will increase the temperature of the lubricating oil that cools the reduction gear. There is a possibility that the response speed is delayed and the reduction gear temperature rises. However, since the current of the electric motor 1 is limited using the oil temperature detected by the oil temperature sensor Sb, the response delay to the lubricating oil temperature is eliminated. It is possible to prevent the speed reducer 2 from being abnormal.
By limiting the electric current of the electric motor 1 in this way, it is possible to prevent an increase in the coil temperature of the electric motor 1 and prevent the electric motor 1 from being overloaded, and suppress the temperature increase of the lubricating oil to reduce the speed reducer 2. It is possible to prevent abnormalities from occurring in advance. Therefore, the abnormality can be detected with high accuracy in the entire range from the low speed high torque region to the high speed low torque region in the output range of the electric motor 1.

  The motor output limiting means 95 starts the output limitation to the electric motor 1 when the first threshold value is exceeded in any threshold value, and when the second threshold value is exceeded, the current to the electric motor 1 is set to zero. To do. By thus limiting the output to the electric motor 1 in stages, the vehicle can be smoothly operated without causing the driver to feel a sudden discomfort with respect to the driver's accelerator operation. The motor output limiting means 95 can prevent the torque command value for the accelerator operation from changing sharply by decreasing the torque command value at a constant rate when the first threshold value is exceeded.

Another embodiment will be described.
In the following description, the same reference numerals are given to the portions corresponding to the matters described in the preceding forms in each embodiment, and the overlapping description is 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.

  As shown in FIG. 6, a pump 28 is provided outside the in-wheel motor unit including the electric motor 1, the wheel bearing 5, and the speed reducer 2, and the pump 28 is driven separately from the in-wheel motor drive device. It may be driven by a source. In this case, the lubricating oil tank of the reduction gear housing 7 can be omitted, and the oil passage to be provided in the motor housing 8 can be reduced. Thereby, the apparatus main body can be made compact. Therefore, the in-wheel motor drive device can be mounted on various vehicles, and versatility can be improved.

The motor output limiting means may limit the motor current at a predetermined ratio (for example, 90%) with respect to the current motor current when the first threshold is exceeded, or reduce the predetermined value. Also good.
The motor output limiting means reduces the motor current with a constant slope when the first threshold is exceeded, and reduces the motor current with a steeper slope than the constant slope when the second threshold is exceeded. Anyway. The slope of the motor current may be a slope that draws a quadratic curve or the like instead of a straight line.

You may provide an oil temperature sensor in lubricating oil paths other than a lubricating oil tank among the lubricating oil paths of a reduction gear.
In this embodiment, although the example which employ | adopted the cycloid type reduction gear was shown, it is not restricted to this, A planetary reduction gear, a 2 axis | shaft parallel reduction gear, and other reduction gears are applicable.

DESCRIPTION OF SYMBOLS 1 ... Electric motor 2 ... Reduction gear 5 ... Wheel bearing 28 ... Pump 29 ... Lubricating oil path 30 ... Supply oil path 38 ... Discharge oil path 95 ... Motor output restriction means Jk ... Lubricating oil supply mechanism U1 ... Control apparatus Sa ... Temperature Sensor Sb ... Oil temperature sensor

The in-wheel motor drive device according to the present invention includes an electric motor 1 for driving a wheel, a wheel bearing 5 for rotating and supporting the wheel, and a deceleration for reducing the rotation of the electric motor 1 and transmitting it to the wheel bearing 5. An in-wheel motor drive device including a machine 2, a lubricant supply mechanism Jk that supplies lubricant to the speed reducer 2, and a controller U <b> 1 that controls the electric motor 1,
The lubricating oil supply mechanism Jk has a supply oil passage 30 for supplying lubricating oil to the speed reducer 2, and a pump 28 for supplying lubricating oil to the speed reducer 2.
The lubricating oil passage 29 of the speed reducer 2 is provided with an oil temperature sensor Sb that detects the temperature of the lubricating oil, the stator 9 of the electric motor 1 is provided with a temperature sensor Sa that detects the temperature of the motor coil 78,
When the coil temperature detected by the temperature sensor Sa exceeds a threshold value determined for the coil temperature in the low speed and high torque region, the control device U1 detects the oil temperature sensor Sb in the high speed and low torque region. in the detected oil temperature is at this time the oil exceeds the threshold value is constant because against temperature, and having a motor output limiting means 95 for limiting the current of the electric motor 1.
Before SL Each "determined threshold" is, for example, it is determined by experiment or simulation or the like.
Limiting the current of the electric motor includes setting the current of the electric motor to “zero”.

An in-wheel motor drive device according to the present invention includes an electric motor that drives a wheel, a wheel bearing that rotatably supports the wheel, a speed reducer that decelerates the rotation of the electric motor and transmits the rotation to the wheel bearing, In an in-wheel motor drive device comprising a lubricant supply mechanism for supplying lubricant to a reduction gear and a control device for controlling the electric motor,
The lubricating oil supply mechanism has a supply oil path for supplying lubricating oil to the speed reducer and a pump for supplying lubricating oil to the speed reducer, and the temperature of the lubricating oil is set in the lubricating oil path of the speed reducer. comprising an oil temperature sensor for detecting the electric motor stator, comprising a temperature sensor for detecting the temperature of the motor coil, wherein the control device, coil temperature the coil temperature detected by the temperature sensor is in the low speed high torque range when exceeding the threshold value determined for, in the high speed low torque range can the oil temperature detected by the oil temperature sensor exceeds a threshold value is constant because for this oil temperature, respectively before Symbol electric Since the motor output limiting means for limiting the motor current is provided, the in-wheel motor drive device detects the temperature of the lubricating oil and the temperature of the motor coil at the same time, and accurately differs over the entire motor output range. Detection can be performed.

Claims (6)

An electric motor for driving the wheel; a wheel bearing for rotating and supporting the wheel; a speed reducer for decelerating the rotation of the electric motor and transmitting it to the wheel bearing; and a lubricating oil for supplying lubricating oil to the speed reducer In an in-wheel motor drive device comprising a supply mechanism and a control device for controlling the electric motor,
The lubricating oil supply mechanism has a supply oil path for supplying lubricating oil to the speed reducer, and a pump for supplying lubricating oil to the speed reducer,
An oil temperature sensor that detects the temperature of the lubricating oil is provided in the lubricating oil path of the speed reducer, and a temperature sensor that detects the temperature of the motor coil is provided in the stator of the electric motor,
The control device limits the current of the electric motor when one or both of a temperature detected by the oil temperature sensor and a temperature detected by the temperature sensor exceed a predetermined threshold. An in-wheel motor drive device comprising motor output limiting means. The in-wheel motor drive device according to claim 1, wherein each of the threshold values of the oil temperature sensor and the temperature sensor includes a first threshold value and a second threshold value that is larger than the first threshold value,
The motor output limiting means starts the output limitation to the electric motor when the first threshold value is exceeded in any threshold value, and sets the current of the electric motor to zero when the second threshold value is exceeded. In-wheel motor drive device.   3. The in-wheel motor drive device according to claim 2, wherein when the first threshold value is exceeded, the motor output limiting unit outputs a torque command value to be input to the electric motor at a constant ratio determined with respect to temperature. Reduce in-wheel motor drive.   4. The in-wheel motor drive device according to claim 2, wherein the motor output limiting unit is configured to output the electric motor when the first and second threshold values are exceeded and then fall below the first threshold value after a predetermined time. An in-wheel motor drive device that releases the output restriction to the motor.   The in-wheel motor drive device according to any one of claims 1 to 4, wherein the pump is disposed on the same axis between the electric motor and the speed reducer. .   5. The in-wheel motor drive device according to claim 1, wherein the pump is provided outside an in-wheel motor unit including the electric motor, the wheel bearing, and the speed reducer. In-wheel motor drive device.

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