JP6099965B2 - In-wheel motor drive device - Google Patents

Description

  The present invention relates to an in-wheel motor drive device used for drive wheels of, for example, an electric vehicle.

  In an electric vehicle, an abnormality in a motor for driving the vehicle has a significant influence. In particular, in-wheel motor drive devices are reduced in size. As a result, wheel bearings, reduction gears, and motors are accompanied by reductions in material usage and high-speed rotation of motors. It becomes. When a short circuit abnormality occurs in, for example, a motor coil of a motor for driving a vehicle while the vehicle is running, the vehicle is not easily moved by towing by an external vehicle because the motor is rotated and the brake is always applied.

  Conventionally, there has been proposed a technique for dividing the weakest part of a transmission shaft in a power transmission path between a wheel and a motor when a large external force exceeding an assumed range is applied to a traveling wheel (patent) Reference 1).

Japanese Patent No. 4877296

  In the prior art, since it is necessary to replace the transmission shaft itself when repairing the vehicle, there is a problem that the number of work steps is increased and the cost is increased.

  An object of the present invention is to provide an in-wheel motor drive device capable of preventing a wheel from being locked when an abnormality occurs in an electric motor during traveling and reducing the number of work steps required for repairing the wheel. Is to provide.

In-wheel motor drive device of the first invention in this inventions will have an electric motor, a wheel bearing for supporting the wheel, and a speed reducer that transmits by reducing the rotation of the electric motor to the wheel bearing In the in-wheel motor drive device, the electric motor and the speed reducer each have a motor rotating shaft and a speed reducer input shaft that are rotatably supported, and the motor rotating shaft and the speed reducer input shaft are greater than or equal to an allowable value. is consolidated through a torque limiter for blocking the transmission of torque, the electric motor has the speed reducer, and the torque limiter each motor housing, the reducer housing, and a torque limiter housing, said motor housing, said reducer housing, and the torque limiter housing, characterized in that you are combined with one another.

  According to this configuration, since the motor rotation shaft and the reduction gear input shaft are connected via the torque limiter that cuts off the transmission of torque exceeding the allowable value, when the abnormality occurs in the electric motor during traveling of the vehicle, the wheels It is possible to prevent an undesired lock state. Then, the vehicle can be self-propelled using an electric motor or the like in which no abnormality has occurred, or the vehicle can be pulled by an external vehicle. After moving the vehicle to a repair shop or the like, for example, only the electric motor causing the abnormality needs to be replaced with a normal electric motor. For this reason, the work man-hours required for repair can be reduced as compared with the prior art. In this case, for example, the allowable torque can be made smaller than the case where a torque limiter is arranged on the output shaft of the reduction gear, and the entire in-wheel motor drive device can be downsized.

The torque limiter may include a pair of flanges that are in contact with each other and capable of transmitting torque, and a pressing unit that applies a pressing force that presses the pair of flanges against each other. When torque exceeding the allowable value is loaded on the torque limiter, torque transmission can be cut off against the pressing force of the pressing means .
An in-wheel motor drive device according to a second aspect of the present invention includes an electric motor, a wheel bearing that supports a wheel, and a speed reducer that decelerates the rotation of the electric motor and transmits the rotation to the wheel bearing. In the wheel motor driving device, the electric motor and the speed reducer each have a motor rotating shaft and a speed reducer input shaft that are rotatably supported, and the motor rotating shaft and the speed reducer input shaft are not less than an allowable value. The torque limiter is connected via a torque limiter that cuts off torque transmission, the torque limiter being opposed to each other and capable of transmitting torque, and pressing means for applying a pressing force that presses the pair of flanges against each other. has, provided with a bearing for rotatably supporting the front SL motor rotation shaft, said pressing means, Ru serves as a preload generating means for generating a preload on the bearing In this case, it is not necessary to newly provide a preload generating means, the number of parts can be reduced, and the structure can be simplified.
The pressing means may be permanent magnets attached to the pair of flanges and attracting each other, and the torque limiter may block transmission of torque exceeding the attraction force by the permanent magnets. When a torque exceeding the allowable value is applied to the torque limiter, torque transmission from the motor rotation shaft to the speed reducer input shaft can be blocked against the attractive force of the permanent magnet.

  The torque limiter may include a pair of flanges that are capable of transmitting torque in opposition to each other, and a connector that connects the pair of flanges and that is broken when a torque greater than the allowable value is input. When the torque limiter is loaded with a torque less than the allowable value, the torque is transmitted from the motor rotation shaft to the reduction gear input shaft. When torque exceeding the allowable value is applied to the torque limiter, the coupling is broken, so that transmission of torque from the motor rotation shaft to the reduction gear input shaft can be cut off.

The torque limiter may be arranged coaxially to the motor rotating shaft. For this reason, it becomes possible to achieve downsizing of the entire apparatus.
The wheel bearing may be rotated by an output member coaxial with the reduction gear input shaft, and the reduction gear input shaft and the motor rotation shaft may be coaxially arranged. In this case, the entire apparatus can be further downsized.

The speed reducer or the wheel bearing is provided with a rotational speed detecting means for detecting the rotational speed of the wheel, and the torque limiter transmits torque exceeding an allowable value from the rotational speed detected by the rotational speed detecting means. It is good also as a thing provided with the determination means which determines whether it interrupted | blocked. As described above, the determination means determines whether or not the torque limiter has blocked the transmission of the torque exceeding the allowable value, so that the electric motor can be easily and reliably controlled thereafter.

When the torque limiter cuts off transmission of torque exceeding an allowable value, output limiting means for limiting output to the electric motor may be provided . For example, when an abnormality occurs in one of the electric motors that respectively drive the left and right drive wheels, the output restricting means is configured to detect one of the electric motors in which the abnormality has occurred, or one of the other electric motors. Limit output. In this way, by limiting the output of the electric motor, the stability of the vehicle can be improved and the vehicle can be driven to a desired location.

The electric motor, the reduction gear, and having a respective said torque limiter housing, if to combine these housings, by combining the housings can be assembled in-wheel motor drive device easily, the housings By separating them from each other, desired parts can be easily replaced.

In-wheel motor drive device of the first invention in this inventions will have an electric motor, a wheel bearing for supporting the wheel, and a speed reducer that transmits by reducing the rotation of the electric motor to the wheel bearing In the in-wheel motor drive device, the electric motor and the speed reducer each have a motor rotating shaft and a speed reducer input shaft that are rotatably supported, and the motor rotating shaft and the speed reducer input shaft are greater than or equal to an allowable value. is consolidated through a torque limiter for blocking the transmission of torque, the electric motor has the speed reducer, and the torque limiter each motor housing, the reducer housing, and a torque limiter housing, said motor housing, said The reduction gear housing and the torque limiter housing are combined with each other. For this reason, when an abnormality occurs in the electric motor during traveling, the wheels can be prevented from being locked, and the number of work steps required for the repair can be reduced .
An in-wheel motor drive device according to a second aspect of the present invention includes an electric motor, a wheel bearing that supports a wheel, and a speed reducer that decelerates the rotation of the electric motor and transmits the rotation to the wheel bearing. In the wheel motor driving device, the electric motor and the speed reducer each have a motor rotating shaft and a speed reducer input shaft that are rotatably supported, and the motor rotating shaft and the speed reducer input shaft are not less than an allowable value. The torque limiter is connected via a torque limiter that cuts off torque transmission, the torque limiter being opposed to each other and capable of transmitting torque, and pressing means for applying a pressing force that presses the pair of flanges against each other. And the pressing means also serves as a preload generating means for generating a preload on the bearing. For this reason, when an abnormality occurs in the electric motor during traveling, the wheels can be prevented from being locked, and the number of work steps required for the repair can be reduced.

It is sectional drawing of the in-wheel motor drive device which concerns on 1st Embodiment of this invention. It is an expanded sectional view of the principal part of the same in-wheel motor drive device. 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 an accelerator input and command torque in the case of restrict | limiting output of the electric motor of the same in-wheel motor drive device. It is sectional drawing of the in-wheel motor drive device which concerns on other embodiment of this invention. It is sectional drawing of the in-wheel motor drive device which concerns on other embodiment of this invention. It is sectional drawing of the in-wheel motor drive device which concerns on other embodiment of this invention. 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 schematically the electric vehicle carrying any in-wheel motor drive device.

  An in-wheel motor drive apparatus according to a first embodiment of the present invention will be described with reference to FIGS. The following description also includes a description of the control method of the in-wheel motor drive device. As shown in FIG. 1, the in-wheel motor drive device includes an electric motor 1, a speed reducer 2, a torque limiter 3, a wheel bearing 4, and a lubricating oil supply mechanism. The speed reducer 2 decelerates the rotation of the electric motor 1 and transmits it to the wheel bearing 4. The wheel bearing 4 that supports the wheel is rotated by an output member 6 that is coaxial with the speed reducer input shaft 5. The reduction gear 2 is interposed between the wheel bearing 4 and the electric motor 1, and the wheel hub that is a driving wheel supported by the wheel bearing 4 and the motor rotating shaft 7 of the electric motor 1 are coaxially arranged. It is connected.

  The speed reducer 2 and the electric motor 1 have an integrated speed reducer / motor housing 8, and a suspension (not shown) in the vehicle is connected to the speed reducer / motor housing 8. In this specification, the side closer to the outside in the vehicle width direction of the vehicle with the in-wheel motor drive device supported by the vehicle is called the outboard side, and the side closer to the center of the vehicle is called the inboard side. .

The reducer / motor housing 8 includes a large-diameter housing portion 8a on the inboard side and a small-diameter housing portion 8b disposed on the outboard side with a smaller diameter than the large-diameter housing portion 8a.
The electric motor 1 is provided in a large-diameter housing portion 8 a on the inboard side of the speed reducer / motor housing 8. 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 in the same large-diameter housing portion and a motor rotor 10 attached to the motor rotating shaft 7. It is.

An outer pin housing 11 described later is accommodated in the small-diameter housing portion 8b of the reduction gear / motor housing 8, and a pump housing 12 is accommodated in the large-diameter housing portion 8a.
The pump housing 12 is adjacent to the outer pin housing 11 in the axial direction. In addition, the pump housing 12 is disposed in the large-diameter housing portion 8a so as to contact the step surfaces of the large-diameter housing portion 8a and the small-diameter housing portion 8a. The opening end on the inboard side of the large-diameter housing portion 8a is closed with a rear cover 13.

  The pump housing 12 has a cylindrical portion 14 that is coaxial with the motor rotating shaft 7 and extends in the axial direction to a predetermined length. First to third bearings 15, 16, and 17 are fitted and fixed to the inner peripheral surface of the cylindrical portion 14. The rear cover 13 has a cylindrical cover cylinder portion 13a that is coaxial with the motor rotating shaft 7 and extends a predetermined length in the other axial direction. A fourth bearing 18 is fitted on the inner peripheral surface of the cover cylinder portion 13a. It is fixed. The 1st thru | or 4th bearing 15,16,17,18 consists of a deep groove ball bearing of the same size in this example. An annular seal mechanism 19 is provided on the inner peripheral surface of the cover cylinder portion 13 a at the inboard side end with respect to the fourth bearing 18.

  The motor rotating shaft 7 is rotatably supported by the first to fourth bearings 15, 16, 17, and 18. The motor rotating shaft 7 transmits the driving force of the electric motor 1 to the speed reducer 2 via the torque limiter 3. A rotor fixing member 20 and a spacer 21 are provided in the middle in the axial direction on the outer peripheral surface of the motor rotating shaft 7. In other words, the rotor fixing member 20 and the spacer 21 are fitted and fixed between the third bearing inner ring and the fourth bearing inner ring on the outer peripheral surface of the motor rotating shaft 7. A motor rotor 10 is attached to the rotor fixing member 20.

  The reduction gear input shaft 5 has one end in the axial direction extending into the motor rotation shaft and is spline-fitted with the motor rotation shaft 7. The output member 6 has a cup portion 6a provided in the small diameter housing portion 8b, and a fifth bearing 22 is provided in the cup portion 6a. The other axial end of the speed reducer input shaft 5 is supported by the fifth bearing 22. Therefore, the speed reducer input shaft 5 and the motor rotation shaft 7 are supported by the first to fifth bearings 15, 16, 17, 18, and 22 so as to be integrally rotatable. In the small-diameter housing portion 8b, first and second eccentric portions 23 and 24 are provided on the outer peripheral surface near the other axial end of the speed reducer input shaft 5. These first and second eccentric portions 23 and 24 are provided with a 180 ° phase shift so that the centrifugal force due to the eccentric motion is canceled out.

  The reduction gear 2 may have a reduction ratio of 6 or more, for example. The speed reducer 2 is a cycloid speed reducer having curved plates 25 and 26, a plurality of outer pins 27, a motion conversion mechanism 28, and counterweights 29 and 29. The curved plates 25 and 26 are curved so that the outer circumference curves alternately inward and outward in the radial direction, and are rotatably provided in the first and second eccentric portions 23 and 24, respectively. A plurality of outer pins 27 are supported on the outer pin housing 11 accommodated in the small-diameter housing portion 8b, and these outer pins 27 are brought into rolling contact with the outer circumferences of the curved plates 25 and 26.

  The motion conversion mechanism 28 is a mechanism for transmitting the rotational motion of the curved plates 25 and 26 to the output member 6. The motion conversion mechanism 28 includes a plurality of inner pins 30 provided in the cup portion 6 a of the output member 6 and through holes provided in the curved plates 25 and 26. The inner pins 30 are arranged at equal intervals in the circumferential direction around the rotation axis of the output member 6. Counterweights 29 and 29 are provided at axial positions adjacent to the first and second eccentric portions 23 and 24 in the speed reducer input shaft 5, respectively.

  FIG. 2 is an enlarged cross-sectional view of a main part of the in-wheel motor drive device. The torque limiter 3 connects the motor rotating shaft 7 and the speed reducer input shaft 5 and interrupts transmission of torque exceeding an allowable value. In this example, the motor rotating shaft 7 includes first and second motor rotating shafts 7a and 7b. The first and second motor rotating shafts 7a and 7b are provided coaxially and are in contact with each other. And a pair of flanges 31 and 31 capable of transmitting torque. The torque limiter 3 includes the pair of flanges 31 and 31 and pressing means 32 that applies a pressing force that presses the pair of flanges 31 and 31 against each other.

  The pressing means 32 is provided between the flange 31 of the second rotating shaft 7b and the second bearing inner ring 16a, and is made of a spring such as a disc spring, for example. The allowable value of the torque when the electric motor 1 (FIG. 1) is abnormal is determined by testing and simulation. Based on the allowable value of the torque, the spring constant of the spring, the surface area of the pair of flanges 31, 31 facing each other, and the like can be defined. When the electric motor is normal, the torque limiter transmits torque by the frictional force generated at the flanges 31, 31 when the pair of flanges 31, 31 are pressed against each other by the pressing means 32.

  When the electric motor 1 (FIG. 1) in which the torque limiter 3 is loaded with a torque exceeding the allowable value is abnormal, the torque limiter 3 can block the transmission of torque against the pressing force by the pressing means 32. In other words, the torque limiter 3 can cut off the torque exceeding the frictional force generated in the flanges 31 and 31. The pressing means 32 also serves as preload generating means for generating preload on the first and second bearings 15 and 16. A retaining ring 33 is provided on the inner peripheral surface of the cylindrical portion 14 of the pump housing 12, and the end surface of the first bearing outer ring 15 a is brought into contact with the retaining ring 33. Further, an outer ring spacer 34 is provided between the first bearing outer ring 15a and the second bearing outer ring 16b, and an inner ring spacer is provided between the first bearing inner ring 15b and the second bearing inner ring 16a. 35 is provided. When the electric motor is normal, the rigidity of the first and second bearings 15 and 16 can be increased by applying a certain preload to the first and second bearings 15 and 16 by the preload generating means.

  As shown in FIG. 1, the wheel bearing 4 includes an outer member 36 having a double-row raceway surface on the inner periphery, an inner member 37 having a raceway surface facing each of the raceway surfaces on the outer periphery, The outer member 36 and the inner member 37 have double row rolling elements interposed between the raceway surfaces. The inner member 37 also serves as a hub for mounting the drive wheel. The wheel bearing 4 is a double-row angular ball bearing, and the rolling elements are balls and are held by a cage for each row.

  The outer member 36 is a stationary raceway, and is fitted and fixed to a housing 38 with a flange 38a attached to the outboard side end of the small diameter housing portion 8b. The flange 38a is provided with bolt insertion holes at a plurality of locations in the circumferential direction. The small diameter housing portion 8b is provided with a through hole at a position corresponding to the bolt insertion hole, and the outer pin housing 11 is provided with a bolt screw hole made of an internal thread at a position corresponding to the bolt insertion hole. The outer member 36 and the housing 38 are fixed to the small diameter housing portion 8b by screwing the fixing bolt inserted into the bolt insertion hole of the flange 38a and the through hole of the small diameter housing portion 8b into the bolt screw hole.

  The inner member 37 is provided with a wheel mounting flange 39. A spline hole is formed in the hollow portion of the wheel mounting flange 39, and the output member 6 is spline-fitted into the hollow portion. A female thread is formed at the tip of the output member 6, and the nut 40 is screwed onto the tip of the output member 6 protruding from the hollow portion, thereby connecting the output member 6 and the wheel mounting flange 39. Yes.

  The lubricating oil supply mechanism 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, and includes a lubricating oil flow path, an oil pump 41, and an oil sump 42. And have. The lubricating oil flow path includes a first flow path 43 provided in the pump housing 12, a second flow path 44 provided in the large diameter housing portion 8a, and a third flow path 45 provided in the rear cover 13. And a fourth flow path described later. The oil sump 42 is a reservoir for storing lubricating oil, and is provided below the small-diameter housing portion 8b.

  The oil pump 41 is provided in the pump housing 12 and forcibly circulates lubricating oil. The oil pump 41 includes, for example, an unillustrated inner rotor that rotates as the output member 6 rotates, an outer rotor that rotates following the rotation of the inner rotor, a pump chamber, a suction port, and a discharge port. It is a cycloid pump having. When the inner rotor is rotated by the rotation of the inner member 37, 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 oil sump 42 is sucked up and flows in from the suction port, and is pumped from the discharge port to the first flow path 43 in the pump housing 12. The second flow path 44 communicates with the first and third flow paths 43 and 45, and the third flow path 45 communicates with the fourth flow path. The lubricating oil pumped to the first channel 43 is sequentially pumped to the fourth channel via the second and third channels 44 and 45.
The fourth flow path includes a motor rotation shaft oil passage 46 provided in the motor rotation shaft 7, a motor oil passage 47, a through hole, an annular gap, and an input shaft oil passage 48 provided in the speed reducer input shaft 5. And oil supply ports 49 and 49 and an oil discharge port 50.

The motor rotation shaft oil passage 46 communicates with the downstream portion of the third passage 45 in the hydraulic pressure feeding direction, and is provided along the shaft center in the motor rotation shaft. The input shaft oil passage 48 communicates with the motor rotation shaft oil passage 46 and extends in the axial direction from the inboard end side to the outboard side in the reducer input shaft 5. The oil supply ports 49 and 49 extend radially outward from the axial position where the eccentric portions 23 and 24 are provided in the input shaft oil passage 48.
The small-diameter housing portion 8 b of the speed reducer / motor housing 8 is provided with an oil discharge port 50 for discharging the lubricating oil used for lubricating the speed reducer 2 to the oil reservoir 42. Therefore, the lubricating oil sent from the third flow path 45 to the motor rotation shaft oil passage 46 is used for lubricating the speed reducer 2 from the oil supply ports 49, 49 of the input shaft oil passage 48. The lubricating oil moves radially outward and downward by centrifugal force and gravity, and is returned to the oil sump 42.

  A plurality of through holes penetrating in the radial direction are provided at the axial position of the motor rotating shaft 7 where the rotor fixing member 20 is provided. The rotor fixing member 20 is provided with a motor oil passage 47 that communicates with the plurality of through holes and extends radially outward. The motor oil passage 47 communicates with an annular gap between the rotor fixing member 20 and the inner peripheral surface of the motor rotor 10. Lubricating oil guided to the through hole from the motor rotating shaft oil passage 46 is guided to the annular gap via the motor oil passage 47 to be used for cooling the electric motor 1. The lubricating oil used for this cooling is discharged from the discharge port formed in the flange of the rotor fixing member 20, moves downward by centrifugal force and gravity, and returns to the oil sump.

FIG. 3 is a block diagram of a control system of the in-wheel motor drive device.
An electronic control unit (ECU) 51, an inverter device 52, and a battery 53 are mounted on the vehicle body. The ECU 51 is a high-order control means that performs overall control and cooperative control of the entire vehicle and gives commands to the inverter device 52, and is connected to each other via a controller area network (abbreviation: CAN) or the like. The ECU 51 includes a microcomputer, its control program, an electronic circuit, and the like.

  The inverter device 52 includes a power circuit unit 54 provided for each electric motor 1 and a motor control unit 55 that controls the power circuit unit 54. The motor control unit 55 may be provided in common for each power circuit unit 54 or may be provided separately, but even if provided in common, each power circuit unit 54. For example, can be controlled independently so that the motor torque is different from each other. The motor control unit 55 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 55 to the ECU 51.

  The power circuit unit 54 includes an inverter 56 that converts the DC power of the battery 53 into three-phase AC power that is used to drive the electric motor 1, and a PWM driver 57 that controls the inverter 56. The electric motor 1 is composed of a three-phase synchronous motor. The inverter 56 is composed of a plurality of semiconductor switching elements (not shown), and the PWM driver 57 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 55 includes a computer, a program executed on the computer, and an electronic circuit, and includes a motor drive control unit 58 as a basic control unit. The motor drive control unit 58 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 51 that is the host control unit, and gives the current command to the PWM driver 57. The motor drive control unit 58 obtains a motor current value to be passed from the inverter 56 to the electric motor 1 from the current detection unit 59 and performs current feedback control. Further, the motor drive control unit 58 obtains the rotation angle of the motor rotor (FIG. 1) of the electric motor 1 from the angle sensor 60 and performs vector control.

In this embodiment, the motor control unit 55 having the above-described configuration is provided with the following output limiting means 61, and the speed reducer 2 or the wheel bearing 4 is provided with a rotational speed detecting means Sa that detects the rotational speed of the wheel 62. . The output limiting means 61 limits the output to the electric motor 1 when the torque limiter 3 (FIG. 2) cuts off the transmission of torque exceeding the allowable value. The output limiting means 61 is a determination means 63, a storage section 64, a current And a control unit 65.
The determination means 63 determines whether or not the torque limiter 3 (FIG. 2) has blocked the transmission of torque exceeding the allowable value from the rotation speed detected by the rotation speed detection means Sa. The determination means 63 is, for example, when the difference between the rotational speeds of the left and right wheels 62 exceeds a predetermined threshold due to the occurrence of an abnormality in one of the electric motors 1 or the angle sensor 60 and the rotational speed detection means. When the difference in rotational speed of Sa is equal to or greater than a predetermined threshold value, it is determined that the torque limiter has blocked transmission of torque exceeding the allowable value. The threshold value is appropriately determined by experiment, simulation, or the like. This threshold value is stored in the storage unit 64 so as to be rewritable, and is read at the time of determination by the determination unit 63 and used for calculation.

  If it is determined by the determination means 63 that the torque limiter has blocked the transmission of the torque exceeding the allowable value, the current control unit 65 is connected to the power circuit unit via the motor drive control unit 58 so as to reduce the current value of the electric motor 1. 54. Specifically, the current control unit 65 commands the power circuit unit 54 via the motor drive control unit 58 so that the motor torque is, for example, 10% or more and 90% or less of the maximum torque at normal time. Note that the current control unit 65 may decrease the current at a predetermined rate, or may decrease the current to a predetermined value.

  FIG. 4 is a diagram showing the relationship between the accelerator input and the command torque when the output of the electric motor of the in-wheel motor drive device is limited. An example in which the output is not limited is also shown in FIG. According to the figure, the accelerator input and the command torque are in a proportional relationship in which the command torque increases as the accelerator input increases. When an abnormality occurs in one of the electric motors and the torque limiter cuts off the transmission of torque exceeding the allowable value, the output limiting means limits the output to the electric motor regardless of the accelerator input.

The effect will be described.
According to the in-wheel motor drive apparatus described above, the motor rotating shaft 7 and the speed reducer input shaft 5 are connected via the torque limiter 3 that cuts off transmission of the torque exceeding the allowable value, so that the electric motor is driven during the traveling of the vehicle. When an abnormality occurs in 1, the vehicle can be prevented from being undesirably locked. Then, the vehicle can be self-propelled using an electric motor or the like in which no abnormality has occurred, or the vehicle can be pulled by an external vehicle. After moving the vehicle to a repair shop or the like, for example, only the electric motor 1 causing the abnormality needs to be replaced with a normal electric motor 1. For this reason, the work man-hours required for repair can be reduced as compared with the prior art. Further, in this case, for example, the allowable torque can be made smaller than when a torque limiter is arranged on the output shaft of the speed reducer 2, and the entire in-wheel motor drive device can be reduced in size. Since the torque limiter 3 can be used repeatedly, it is more advantageous in running cost than the conventional one.

Since the torque limiter 3 is disposed coaxially with the motor rotation shaft 7, the entire apparatus can be made compact. Since the wheel bearing 4 is rotated by an output member 6 coaxial with the speed reducer input shaft 5, and the speed reducer input shaft 5 and the motor rotating shaft 7 are coaxially arranged, the overall device can be further reduced in size. It becomes possible.
By determining whether or not the torque limiter 3 has blocked the transmission of the torque exceeding the allowable value by the determination means 63, the electric motor 1 can be easily and reliably controlled thereafter.
The output restricting means 61 is, for example, one of the electric motors 1 and 1 that drives the left and right drive wheels 62 and 62, respectively. Alternatively, the output of one and the other electric motors 1 and 1 is limited. In this way, by limiting the output of the electric motor 1, the vehicle stability can be improved and the vehicle can travel to a desired location.

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 the enlarged portion of FIG. 5, the torque limiter 3 includes a pair of flanges 31, 31, and a coupling tool 66 that is connected when the pair of flanges 31, 31 are connected and a torque exceeding a predetermined allowable value is input. It is good also as what has. For example, the connector 66 includes a plurality of pins arranged at regular intervals in the circumferential direction. When torque less than the allowable value is applied to the torque limiter 3, torque is transmitted from the motor rotation shaft 7 to the reduction gear input shaft 5. When torque exceeding the allowable value is applied to the torque limiter 3, the coupling 66 is broken, so that transmission of torque from the motor rotation shaft 7 to the reduction gear input shaft 5 can be cut off. In this case, the surface area of the flange 31 of the torque limiter 3 can be made smaller than that of the first embodiment, and thus the torque limiter 3 can be downsized in the radial direction.

  As shown in FIG. 6, the pressing means 32 </ b> A of the torque limiter 3 may be a permanent magnet that is attached to each of the pair of flanges 31 and 31 and attracts each other. An annular groove is formed on the surface of each flange 31 facing each other, and a permanent magnet is fitted into and fixed to the annular groove via an adhesive or the like. The torque limiter 3 cuts off the transmission of torque exceeding the attractive force by the permanent magnet. When torque exceeding the allowable value is loaded on the torque limiter 3, transmission of torque from the motor rotation shaft 7 to the reduction gear input shaft 5 can be blocked against the attractive force of the permanent magnet.

  As shown in FIG. 7, the rotational speed detection means 67 is provided in the hub, and the determination means 63 (FIG. 3) determines that the torque limiter 3 has a torque exceeding the allowable value based on the rotational speed detected by the rotational speed detection means 67. It is good also as what determines whether transmission is interrupted | blocked.

As shown in FIG. 8, the electric motor 1, the speed reducer 2, and the torque limiter 3 each have a motor housing Hm, a speed reducer housing Hg, and a torque limiter housing Ht, and these housings Hm, Hg, and Ht are combined. It may be configured.
In each of the above embodiments, the pump housing is accommodated in the large-diameter housing portion of the reduction gear / motor housing, but in this example, the pump housing is omitted. The motor housing Hm is provided with an oil pump 41 and a torque limiter housing Ht. In this example, the motor rotation shaft 7 includes first to third motor rotation shafts 7a, 7b, and 7c provided coaxially, and the outer peripheral surface of the third motor rotation shaft 7c is the first motor rotation shaft 7a. It is spline-fitted to the inner peripheral surface.

Further, the outer member 36 of the wheel bearing 4 has a flange 36a attached to the outboard side end of the reduction gear housing Hg. A step portion is formed on the outer peripheral surface on the inboard side of the hollow portion through which the output member 6 is inserted in the inner member 37, and the inner ring is fitted and fixed to the step portion. A row of raceway surfaces is integrally formed on the outer circumferential surface of the inner member 37, and another row of raceway surfaces is formed on the outer circumferential surface of the inner ring.
In the configuration of FIG. 8, the in-wheel motor drive device can be easily assembled by combining the housings Hm, Hg, and Ht, and desired parts can be easily separated by separating the housings Hm, Hg, and Ht from each other. Can be replaced.

FIG. 9 is a diagram schematically showing an electric vehicle on which any one of the in-wheel motor driving devices is mounted. This electric vehicle is a four-wheeled vehicle in which the wheels 62 that are the left and right rear wheels of the vehicle body 68 are drive wheels, and the wheels 62 that are the left and right front wheels are driven wheels. The front wheel 62 is a steering wheel. The electric vehicle of this example includes drive units that drive the left and right wheels 62 and 62 that are drive wheels by independent electric motors 1 and 1, respectively. The rotation of the electric motor 1 is transmitted to the wheel 62 via the speed reducer 2 and the wheel bearing 4. In the drive unit, a part or the whole of the electric motor 1 is disposed in the wheel 62 to constitute an in-wheel motor drive device including the electric motor 1, the speed reducer 2, and the wheel bearing 4.
Since any one of the in-wheel motor driving devices is mounted on this electric vehicle, it is possible to prevent the wheels from being locked when an abnormality occurs in the electric motor during traveling, and to reduce the work man-hours required for repairing the wheels. Can be achieved.

DESCRIPTION OF SYMBOLS 1 ... Electric motor 2 ... Reduction gear 3 ... Torque limiter 4 ... Wheel bearing 5 ... Reduction gear input shaft 7 ... Motor rotating shaft 31 ... Flange 32, 32A ... Pressing means 61 ... Output restriction means 62 ... Wheel 63 ... Determination means 67 ... Rotation speed detection means

Claims (8)

In an in-wheel motor drive device comprising: an electric motor; a wheel bearing that supports a wheel; and a speed reducer that decelerates rotation of the electric motor and transmits the reduced speed to the wheel bearing.
The electric motor and the speed reducer each have a motor rotation shaft and a speed reducer input shaft that are rotatably supported,
These motor rotation shaft and the reduction gear input shaft, is consolidated through a torque limiter for cutting off transmission of more than the allowable value of the torque,
The electric motor, the speed reducer, and the torque limiter each have a motor housing, a speed reducer housing, and a torque limiter housing, and the motor housing, the speed reducer housing, and the torque limiter housing are combined with each other. in-wheel motor drive device comprising a call.   2. The in-wheel motor drive device according to claim 1, wherein the torque limiter includes a pair of flanges that are opposed to each other and can transmit torque, and a pressing unit that applies a pressing force that presses the pair of flanges against each other. In-wheel motor drive device. In an in-wheel motor drive device comprising: an electric motor; a wheel bearing that supports a wheel; and a speed reducer that decelerates rotation of the electric motor and transmits the reduced speed to the wheel bearing.
The electric motor and the speed reducer each have a motor rotation shaft and a speed reducer input shaft that are rotatably supported,
These motor rotation shaft and reduction gear input shaft are connected via a torque limiter that cuts off the transmission of torque exceeding the allowable value,
The torque limiter has a pair of flanges that are in contact with each other and capable of transmitting torque, and a pressing unit that applies a pressing force to press the pair of flanges against each other,
Comprising a bearing for rotatably supporting the motor rotation shaft, said pressing means, in-wheel motor drive device serving as a preload generating means for generating a preload to the bearing.   3. The in-wheel motor drive device according to claim 2, wherein the pressing means is a permanent magnet that is attached to each of the pair of flanges and attracts each other, and the torque limiter transmits torque exceeding the attractive force of the permanent magnet. An in-wheel motor drive device that cuts off the motor.   The in-wheel motor drive device according to claim 1, wherein the torque limiter includes a pair of flanges capable of transmitting torque in opposition to each other, and a connecting tool that is connected when the pair of flanges are connected and a torque exceeding the allowable value is input. And an in-wheel motor drive device. In-wheel motor drive device according to any one of claims 1 to 5, in-wheel motor drive device disposed coaxially the torque limiter in the motor rotational shaft.   The in-wheel motor drive device according to any one of claims 1 to 6, wherein the wheel bearing is rotated by an output member coaxial with the reducer input shaft, and further, the reducer input shaft and the An in-wheel motor drive device in which the motor rotation shaft is arranged coaxially. The in-wheel motor drive device according to any one of claims 1 to 7, wherein the reduction gear or the wheel bearing is provided with a rotation speed detection means for detecting a rotation speed of the wheel, and the rotation speed. from the rotational speed detected by the detection means, when said torque limiter comprises a judging device for judging whether or not to block the transmission of more than the allowable value of the torque, the torque limiter is cut off the transmission of more than the allowable value of the torque , in-wheel motor drive device provided with an output limiting means for limiting the output to the electric motor.

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