JP2013052768A - In-wheel motor drive unit for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-size compact in-wheel motor drive unit for an electric vehicle, so adapted as to be capable of adding a parking brake function under an attempt of compacting itself in the length in axial direction.SOLUTION: A brake device 40 of drum type is installed within a motor case 11 for an electric motor 10 that rotationally drives a hub wheel 26 for driving a wheel, while during parking, the brake device 40 adds a braking force to the rotor 13 of the electric motor 10 for keeping the state of halt condition. The provision of the brake drum section 42 of the brake device 40 at the side part of the rotor 13 of the electric motor 10 prevents the length in the axial direction of the motor drive unit from being extended even if a parking brake function is added.

Description

  The present invention relates to a motor drive device for an in-wheel electric vehicle that drives wheels of a vehicle.

  FIG. 1 schematically shows an in-wheel electric vehicle. In this electric vehicle, a motor drive device A using an electric motor as a drive source is housed inside a pair of left and right rear wheels 1 as drive wheels, and each of the pair of rear wheels 1 is independently provided by the motor drive device A. To drive.

  As a motor drive device A employed in the in-wheel electric vehicle as described above, one described in Patent Document 1 has been conventionally known. In the motor drive device described in Patent Document 1, the rotation output from the rotor shaft of the electric motor is reduced by the reduction mechanism and output to the hub wheel, and the rotation of the hub wheel is transmitted to the wheel. Yes.

  Here, in the motor drive device described in Patent Document 1, since the braking mechanism is arranged at the end of the wheel opposite to the wheel, the electric motor is arranged close to the wheel of the wheel. Therefore, the support structure for the electric motor can be simplified.

  In addition, since the braking mechanism brakes the rotor shaft on the driving side with a small torque, not on the output side that has been decelerated, a small-sized braking mechanism can be adopted, and the motor driving device can be downsized. It has the feature that can be aimed at.

JP 2000-52788 A

  By the way, although the in-wheel motor drive device described in Patent Document 1 has a braking mechanism, the braking mechanism is a service brake for driving that applies a braking force when the vehicle travels. There is nothing listed.

  Here, in the in-wheel motor drive device, downsizing is required because it is attached to a wheel, and there is a concern about the upsizing by adding a parking brake function for parking, and a compact and compact in-wheel motor with a parking brake function. A drive is required.

  An object of the present invention is to provide a small and compact in-wheel motor drive device for an electric vehicle in which a parking brake function can be added in a state where the axial length is made compact.

  In order to solve the above-described problems, in the present invention, an electric motor having a fixedly arranged stator incorporated in a motor case, a rotor that rotates in the stator by energization of a coil of the stator, and a rotational drive by the electric motor An electric vehicle motor drive device comprising a wheel drive hub wheel for transmitting the rotation to a drive wheel, wherein a parking drum brake device is provided in the motor case, and the brake drum of the brake device is provided. A configuration is adopted in which a portion is provided on a side portion of the rotor to brake the rotor.

  In the in-wheel motor drive device for an electric vehicle configured as described above, the parking brake device is operated to brake the rotor when the electric vehicle is parked. At this time, since the brake device brakes the rotor on the driving side with a small torque, a small brake device can be adopted.

  Moreover, since the brake device is a drum type and the brake drum portion is provided on the side surface of the rotor, the axial length of the motor drive device is greatly increased by assembling the brake device into the motor case. Thus, an in-wheel motor drive device with a compact parking brake device having an axial length can be obtained.

  Here, the in-wheel motor drive device for an electric vehicle may be one that transmits the rotation of the rotor of the electric motor directly to the hub wheel, or between the rotor of the electric motor and the hub wheel. A speed reduction mechanism may be provided to reduce the rotation of the rotor and transmit it to the hub wheel.

  By adopting a planetary gear type reduction mechanism as the reduction mechanism and disposing the planetary gear type reduction mechanism inside the rotor, a compact in-wheel motor drive device for an electric vehicle having an axial length can be obtained. it can.

  As a brake device, a guide pin protruding from the inner surface of the cover of the motor case, and swingable around the guide pin, contact the inner diameter surface of the brake drum portion by swinging outward, and the brake A pair of arc-shaped brake shoes that apply a braking force to the drum portion, a return spring that urges each of the pair of brake shoes inward, and a cover of the motor case to swing the pair of brake shoes. A rotatable camshaft having a cam portion disposed between the side end portions at the inner end portion and swinging each of the pair of brake shoes outward by rotation of the cam portion, and the camshaft A lever having one end connected to an outer end located outside through the cover, and a lever operating wire having one end connected to the swinging end of the lever Then, the cam shaft can be rotated by pulling the wire, and the pair of brake shoes can be swung outwardly by the cam portion and pressed against the inner periphery of the brake drum portion. .

  The pulling of the wire may be by manual operation or by actuation of an actuator.

  In the in-wheel motor drive device for an electric vehicle according to the present invention, when the rotation of the rotor is directly transmitted to the hub wheel, a cylindrical concave portion is provided on a side surface of the rotor, and an outer peripheral wall of the concave portion is used as a brake drum portion. Thus, since the rotor serves as a brake drum portion, the number of parts can be reduced. In addition, since the brake shoe is housed inside the rotor, a compact in-wheel motor drive device having an axial length can be obtained.

  Here, when a rotor has a side plate, you may make it provide a cylindrical brake drum part in the side surface of the side plate.

  In the in-wheel motor drive device for an electric vehicle according to the present invention, a parking drum brake device is provided in the motor case, the brake drum portion of the brake device is provided on the side of the rotor, and the rotor is braked. Thus, the parking brake function can be added without significantly increasing the axial length, and a compact and compact motor driving device with a parking brake can be obtained.

Schematic diagram of an electric vehicle The front view which shows embodiment of the in-wheel motor drive device for electric vehicles which concerns on this invention 2 is a longitudinal sectional view of the in-wheel motor drive device shown in FIG. Sectional drawing which expands and shows a part of FIG. Sectional view along line VV in FIG. Schematic of the lever swing drive device shown in FIG. The front view which shows other embodiment of the in-wheel motor drive device for electric vehicles which concerns on this invention FIG. 7 is a longitudinal sectional view of the in-wheel motor driving device shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 2 to 5 show an embodiment of an in-wheel motor drive device for an electric vehicle according to the present invention. As shown in FIG. 2, an in-wheel motor drive device A is provided inside the wheel 2 in the drive wheel 1.

  The in-wheel motor drive device A has an electric motor 10 and a wheel bearing 20 provided on one side of the electric motor 10.

  As shown in FIG. 3, the electric motor 10 includes a motor case 11, a stator 12 incorporated inside the motor case 11, and a rotor 13 incorporated inside the stator 12.

  The motor case 11 includes a cylindrical case main body 14 and a cover 15 that closes an opening at one end of the case main body 14, and the cover 15 has a cylindrical portion 16 that is fitted into the opening end of the case main body 14. The fitting portion between the cylindrical portion 16 and the case main body 14 is sealed by incorporating a seal ring 17.

  As shown in FIG. 4, the rotor 13 is provided with a cylindrical portion 13b on the outer periphery of the disc portion 13a, a flange portion 13c provided at one end portion of the outer periphery of the cylindrical portion 13b, and the other end portion of the cylindrical portion 13b. A permanent magnet 13e provided on the outer periphery of the cylindrical portion 13b is sandwiched from both sides by the attached side plate 13d, and is rotated in the stator 12 by energizing the coil 12a of the stator 12 shown in FIG. It has become.

  As shown in FIGS. 3 and 4, a boss portion 13f is formed at the center of the disc portion 13a of the rotor 13, and the rotor shaft 18 is inserted into the boss portion 13f. The rotor shaft 18 is prevented from rotating around the rotor 13 by a key 19 and rotates together with the rotor 13, and the rotor shaft 18 is rotatably supported by a wheel bearing 20.

  As shown in FIG. 3, the wheel bearing 20 supports a bearing outer ring 21, an inner member 22 inserted into the bearing outer ring 21, and the inner member 22 and the bearing outer ring 21 so as to be relatively rotatable. It consists of the double row rolling elements 23 which do.

  A vehicle body mounting flange 24 is provided on the outer periphery of the bearing outer ring 21, and the vehicle body mounting flange 24 is abutted against an outer surface of an inward flange 14 a provided at the other end of the case body 14, and is in contact with the inward flange 14 a. The case body 14 is attached by tightening a bolt 25 to be screwed.

  The inner member 22 includes a hub ring 26 and a bearing inner ring 27 provided on an inner side end portion of the hub ring 26, and the bearing inner ring 27 is a small-diameter shaft formed at the inner side end portion of the hub ring 26. It is fitted to the part 26a. Each of the hub ring 26 and the bearing inner ring 27 is rotatably supported by the rolling elements 23 incorporated between the bearing outer rings 21 and the seal members 28 incorporated on the outer sides of the rolling elements 23. Both end openings of the bearing space formed at opposite ends of the outer ring 21 and the inner member 22 are closed.

  The hub wheel 26 is fitted to the rotor shaft 18, and the rotor shaft 18 and the hub wheel 26 are relatively prevented from rotating by engagement by the serration 29. For this reason, the rotor shaft 18 is rotatably supported by the bearing outer ring 21 together with the hub ring 26.

  The hub wheel 26 is provided with a wheel mounting flange 30 on the outer periphery of the outer end of the bearing outer ring 21, and a nut 32 is screwed to each of a plurality of bolts 31 provided on the wheel mounting flange 30. The brake rotor 33 that forms a service brake and the wheel 2 of the drive wheel 1 are attached to the wheel mounting flange 30 by tightening the nut 32.

  In the motor case 11, a drum-type brake device 40 for parking is provided. As shown in FIGS. 4 and 5, the brake device 40 is configured such that the disk portion 13 a forming the rotor 13 is positioned at the axial center of the cylindrical portion 13 b provided on the outer periphery of the disk portion 13 a. A cylindrical concave portion 41 is formed on one side facing the cover 15, and an outer peripheral wall of the concave portion 41, that is, a part of the cylindrical portion 13 b is used as a brake drum portion 42.

  Then, a pair of arc-shaped brake shoes 43 are incorporated at opposing positions in the brake drum portion 42, and opposite one end portions of the pair of brake shoes 43 are supported by guide pins 44 protruding from the inner side surface of the cover 15. The pair of brake shoes 43 is urged inward by a return spring 45 stretched between the pair of brake shoes 43 and penetrates the cover 15. A cam portion 48 is provided at an inner end portion of a camshaft 47 that is rotatably supported by a bearing 46 provided in the penetrating portion, and the cam portion 48 is interposed between the swing side end portions of the pair of brake shoes 43. Arranged, connecting one end of the lever 49 to the end located through the cover 15 of the camshaft 47 and connecting the wire 50 to the other end of the lever 49; The cam shaft 47 is rotated by pulling the wire 50, and each of the pair of brake shoes 43 is swung outward by the rotation of the cam portion 48 and pressed against the inner periphery of the brake drum portion 42. .

  Here, the wire 50 may be pulled by manually swinging the operation lever, or the wire 50 may be pulled using an actuator. As the actuator, an electric linear actuator or an electric actuator 51 shown in FIG. 6 can be employed.

  In FIG. 6, the specific configuration of the electric actuator 51 is omitted, but the worm wheel incorporated in the gear case 53 is driven by the motor 52 to rotate the worm wheel meshed with the worm wheel. A wire take-up drum is provided on the same axis, and the wire is taken up by the rotation of the wire take-up drum.

  In the brake device 40, a lining 54 is provided on the outer periphery of the brake shoe 43 in order to enhance the braking effect. Here, the electric motor 10 may be cooled by oil stored in the motor case 11. In that case, as the lining 54, it is preferable to use a lining used in a wet multi-plate clutch.

  The in-wheel motor drive device for an electric vehicle shown in the embodiment has the above-described structure, and when the vehicle travels, the rotor 13 is rotated by energizing the coil 12a of the stator 12 forming the electric motor 10. The rotation of the rotor shaft 18 that rotates with the wheel 13 is transmitted from the hub wheel 26 to the wheel 2 to rotate the drive wheel 1.

  When the vehicle is parked, the wire 50 shown in FIG. 6 is pulled. By pulling the wire 50, the lever 49 swings and the camshaft 47 rotates, and by rotation of the cam portion 48 formed on the camshaft 47, the pair of brake shoes 43 swings outward and the brake A pressing force is applied to the rotor 13 by being pressed against the inner periphery of the drum portion 42.

  As described above, since the rotor 13 can be held in the stopped state by operating the brake device 40, it is not necessary to step on the brake pedal of the service brake and maintain the depressed state during parking. Moreover, since the stop state can be maintained even if the driver gets off, the safety of the vehicle can be improved.

  In order to further enhance safety, in the operating state of the brake device 40, a control unit that controls the electric motor 10 is prevented from outputting a control signal to the electric motor, or a switch incorporated in the motor drive circuit is opened. Thus, it is preferable that the stator 12 of the electric motor 10 is not energized and cannot start.

  In the embodiment, a cylindrical concave portion 41 is provided on the side surface of the rotor 13, the outer peripheral wall of the concave portion 41 is used as the brake drum portion 42, and the rotor 13 serves as the brake drum portion. The number of points can be reduced. Moreover, since the brake shoe 43 is accommodated inside the rotor 13, an in-wheel motor drive device for an electric vehicle having a compact axial length can be obtained.

  7 and 8 show another embodiment of the in-wheel motor drive device for an electric vehicle according to the present invention. In this embodiment, a drive axle 60 is provided coaxially with the rotor shaft 18, the drive axle 60 and the hub wheel 26 are coupled by serrations 29, and the rotor shaft 18 is interposed between the rotor shaft 18 and the drive axle 60. Is provided with a speed reduction mechanism 70 that decelerates the rotation of the motor and transmits it to the drive axle 60.

  Further, an end plate 61 is formed in the motor case 11, and a cylindrical bulging portion 62 that enters the rotor 13 is provided at the center of the end plate 61, and an opening of the bulging portion 62 is formed in the bearing outer ring 21. The speed reduction mechanism 70 is incorporated in a speed reduction mechanism accommodation space 63 formed inside the bulging portion 62, and the speed reduction mechanism 70 is assembled with oil accommodated in the speed reduction mechanism accommodation space 63. Lubricated.

  Further, a brake drum portion 64 of the drum brake device 40 is provided on the side plate 13 d of the rotor 13, and a pair of brake shoes 43 are incorporated in the brake drum portion 64.

  Here, the speed reduction mechanism 70 includes a sun gear 71 provided at the shaft end of the rotor shaft 18, an internal gear 72 fitted and fixed to the inner diameter surface of the bulging portion 62, and an internal gear 72. It consists of a planetary gear type composed of a peripheral inner tooth and a planetary gear 73 meshing with each of the outer peripheral teeth of the sun gear 71.

  Since other configurations are the same as those of the embodiment shown in FIG. 3, the same components are denoted by the same reference numerals and description thereof is omitted.

  Also in the embodiment shown in FIG. 7 and FIG. 8, the rotor 13 can be held in a stopped state by operating the brake device 40. Therefore, when parking, the brake pedal of the service brake is depressed, and the depressed state. There is no need to maintain. Moreover, since the stop state can be maintained even if the driver gets off, the safety of the vehicle can be ensured.

  Moreover, since the brake device 40 brakes the rotor shaft 18 on the drive side with a small torque instead of the decelerated output side, a small brake device 40 can be adopted.

  Further, when a planetary gear type is used as the speed reduction mechanism 70 and the planetary gear type speed reduction mechanism 70 is arranged inside the rotor 13, an in-wheel motor drive for an electric vehicle having a compact axial length is provided. A device can be obtained.

DESCRIPTION OF SYMBOLS 1 Drive wheel 10 Electric motor 11 Motor case 12 Stator 13 Rotor 15 Cover 26 Hub wheel 40 Drum type brake device 41 Cylindrical recessed part 42 Brake drum part 43 Brake shoe 44 Guide pin 45 Return spring 47 Camshaft 48 Cam part 49 Lever 50 Wire 64 Brake drum 70 Deceleration mechanism

Claims (7)

An electric motor having a fixedly arranged stator incorporated in a motor case and a rotor that rotates in the stator by energization of a coil of the stator, and a wheel drive that is rotated by the electric motor and transmits the rotation to a driving wheel In-wheel motor drive device for an electric vehicle comprising a hub wheel for
A parking drum brake device is provided in the motor case, and a brake drum portion of the brake device is provided on a side of the rotor to brake the rotor. Wheel motor drive device.   The in-wheel motor drive device for electric vehicles of Claim 1 with which the reduction mechanism which decelerates the rotation of the rotor of the said electric motor, and transmits it to a hub wheel between the said electric motor and the said hub wheel was provided.   The in-wheel motor drive device for electric vehicles according to claim 2 in which said reduction gear mechanism consists of a planetary gear type, and the planetary gear type reduction mechanism is arranged inside said rotor.   The brake device has a guide pin projecting from the inner surface of the cover of the motor case, and is swingable about the guide pin. The brake device contacts the inner diameter surface of the brake drum portion by swinging outward. A pair of arc-shaped brake shoes for applying a braking force to the brake drum portion, a return spring for urging each of the pair of brake shoes inward, and the cover penetrating the pair of brake shoes. A rotatable camshaft having a cam portion disposed between the swinging side end portions at the inner end portion and swinging each of the pair of brake shoes outward by rotation of the cam portion, and the cam A lever having one end connected to an outer end located outside through the cover of the shaft, and a lever operating wire having one end connected to the swinging end of the lever In-wheel motor drive device for an electric vehicle according to any of claims 1 to 3 comprising a.   The in-wheel motor drive device for electric vehicles in any one of Claims 1 thru | or 4 which provided the cylindrical recessed part in the side surface of the said rotor, and made the outer peripheral wall of the recessed part the brake drum part.   The in-wheel motor drive device for electric vehicles in any one of Claims 1 thru | or 4 with which the said rotor has a side plate and provided the cylindrical brake drum part on the side surface of the side plate.   The in-wheel motor drive device for an electric vehicle according to any one of claims 1 to 5, wherein the electric motor is not energized when the brake device is operated.

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