JP2005145122A - Motor driving system of automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assure a comfortable driving feeling or a running performance without damaging a wide degree of freedom for a motor mounting position that is a merit of motor driving operation. <P>SOLUTION: A motor 4 is fixed to a side of a suspension mechanism to a vehicle body 1, and an output shaft 4a of the motor 4 and a hub shaft 3 of each of wheels 2 are connected by a driving force transmission mechanism with the intervention of a tri-port type constant velocity universal joint 8 forming an extension or shrinking part with a rotating shaft 7, thereby a comfortable driving feeling and a running performance are assured without damaging a wide degree of freedom of a motor mounting position that is a merit of motor driving operation. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a motor drive system for an automobile provided with a motor in which an axle is suspended from a vehicle body via a suspension mechanism and drives the axle.

  Automobiles equipped with motors for driving axles include electric vehicles that are driven only by motors, and so-called hybrid vehicles that use different engines and motors. In addition, suspension mechanisms that suspend the axles from the vehicle body are often used in passenger cars, independent suspension systems that independently suspend the axles of each wheel connected to a universal joint, and are often used in trucks, etc. There is an axle suspension system in which the axles of the wheels are integrally suspended.

  In a motor drive system of an automobile having such a suspension mechanism and a drive motor, a so-called motor and a reduction gear mechanism are directly connected to an axle, and the motor and the reduction gear mechanism are suspended by a suspension mechanism together with the axle. A drive shaft on the differential device side and a drive shaft on the wheel side are the same as in-wheel type devices (for example, refer to Patent Document 1) and a motor and a transmission connected to a differential device to drive a conventional engine. (Axes) are connected by a universal joint (for example, see Patent Document 2).

JP 2002-247713 (page 4-7, Fig. 1-2) JP 2003-72392 A (page 2-4, FIG. 2-3)

  The in-wheel type motor drive system described in Patent Document 1 does not require a differential device or a universal joint and has an advantage that the drive force transmission mechanism can be slimmed. However, the motor and the reduction gear mechanism are suspended together with the axle. Therefore, there is a problem that unsprung weight increases and riding comfort and running performance deteriorate. In addition, there is a problem that the mounting environment is bad such that the motor is directly subjected to a shock due to unevenness of the road surface and the water is easily sprayed at a low position.

  On the other hand, the motor drive system of the type in which the motor and the transmission are connected to the differential device described in Patent Document 2 employs an independent suspension type suspension mechanism, so that the unsprung weight does not increase, and the hybrid vehicle However, a wide degree of freedom in the installation position of the drive source (motor), which is a merit of motor drive, is impaired. For this reason, it is not possible to expect a reduction in the size of the driving force transmission device and expansion of the room / loading room space.

  Accordingly, an object of the present invention is to ensure ride comfort and running performance without impairing a wide degree of freedom of the motor installation position, which is a merit of motor driving.

  In order to solve the above-described problems, the present invention provides a motor drive system for an automobile, in which an axle of a wheel is suspended from a vehicle body via a suspension mechanism and includes a motor for driving the axle, and the motor is attached to the vehicle body side. A configuration is adopted in which the output shaft of the motor and the axle are connected by a driving force transmission mechanism having a telescopic portion.

  In other words, by attaching the motor to the vehicle body side and connecting the output shaft and axle of this motor with a driving force transmission mechanism having a telescopic part, without impairing the wide flexibility of the motor installation position, which is the merit of motor driving , To ensure ride comfort and driving performance.

  The installation environment can be improved by installing the motor above the upper surface of the tire of the wheel.

  By making the expansion / contraction part of the driving force transmission mechanism have a shock absorber function, the ride quality of the automobile can be further improved.

  A sliding type constant velocity universal joint can be used for the expansion / contraction part provided with the shock absorber function. Examples of the sliding type constant velocity universal joint include a tripport type constant velocity universal joint and a double offset type constant velocity universal joint.

  A ball spline can also be used for the expansion / contraction part provided with the shock absorber function.

  Both ends of the expansion / contraction part of the driving force transmission mechanism may be supported by a constant velocity universal joint.

  A motor can be reduced in size by providing a gear reduction device in the driving force transmission mechanism.

  Realization of an advanced four-wheel drive system is expected by providing the motor individually on all wheels.

  In the motor drive system for an automobile according to the present invention, the motor is mounted on the vehicle body side of the suspension mechanism, and the output shaft and the axle of the motor are connected by the drive force transmission mechanism having the telescopic portion. Riding comfort and running performance can be ensured without impairing the wide range of freedom of the motor installation position, which can be expected to make the driving force transmission device more compact and expand the room / loading space. In addition, it is possible to prevent the motor from directly receiving a shock due to road surface unevenness or the like.

  The installation environment can be improved by installing the motor above the upper surface of the tire of the wheel.

  By making the expansion / contraction part of the driving force transmission mechanism have a shock absorber function, the ride quality of the automobile can be further improved.

  A motor can be reduced in size by providing a gear reduction device in the driving force transmission mechanism.

  Realization of an advanced four-wheel drive system is expected by providing the motor individually on all wheels.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the motor drive system for an automobile drives a hub shaft 3 as an axle of a wheel 2 suspended by a suspension mechanism on a vehicle body 1 by a motor 4 attached to the vehicle body 1 side. The output shaft 4a of the motor 4 is rotated in order of a shaft joint 5, a fixed type constant velocity universal joint 6, a rotating shaft 7, a sliding type constant velocity universal joint, a triport type constant velocity universal joint 8, and a fixed type constant velocity universal joint. 9, it is transmitted to the bevel gear 11 a via the shaft coupling 10, and further transmitted to the hub shaft 3 via the bevel gear 11 b meshing with the bevel gear 11 a and the shaft coupling 12.

  The motor 4 is fixed to the vehicle body 1 above the upper surface of the tire 2a of the wheel 2 via a rubber mount 4b. The motor 4 has a reduction mechanism using a planetary gear. Instead of providing a reduction mechanism on the motor 4 side, a reduction ratio can be provided between the bevel gears 11a and 11b described later. Although illustration is omitted, the motors 4 are individually provided on all the wheels 2 and are driven by four wheels.

  The shaft joint 5 connects the output shaft 4a of the motor 4 and the outer ring 6a of the fixed type constant velocity universal joint 6 by spline coupling. The outer ring 6a is rotatably supported on the vehicle body 1 by an angular ball bearing 13. Yes. The angular ball bearing 13 is preloaded by tightening the nut 14. One end of the rotating shaft 7 is connected to the inner ring 6b of the fixed type constant velocity universal joint 6 by spline coupling.

  As shown in FIGS. 2A and 2B, the other end of the rotary shaft 7 is connected to the trunnion 8b of the triport type constant velocity universal joint 8 by spline coupling. It is transmitted to the outer ring 8a via the trunnion 8b, needle 8c and roller 8d of the constant velocity universal joint 8. The roller 8d is integral with the trunnion 8b and is slidable in the axial direction of the outer ring 8a. An expansion / contraction portion is formed between the rotating shaft 7 connected to the trunnion 8b and the outer ring 8a.

  The outer ring 8 a of the tripod type constant velocity universal joint 8 is formed in a cylinder shape, filled with oil inside, and one end into which the rotary shaft 7 is inserted is closed by a lid 15. Between the rotary shaft 7 and the lid 15, a slide bearing 16 for guiding the axial movement of the rotary shaft 7 accompanying expansion and contraction with the outer ring 8a is provided, and a seal 17 for preventing oil leakage is attached. Yes. Although not shown, a gasket or the like for preventing oil leakage is also attached between the outer ring 8a and the lid 15.

  A flange 7a is provided at the tip of the rotary shaft 7 inserted into the outer ring 8a, and orifice units 18a, 18b, and 18c forming an orifice 18 are attached between the flange 7a and the trunnion 8b. The orifice 18 restricts the movement of oil in the outer ring 8a accompanying expansion and contraction between the outer ring 8a and the rotating shaft 7, and exhibits a shock absorber function. The orifice unit 18a splined to the rotating shaft 7 and the inner surface of the outer ring 8a and the flange 7a of the rotating shaft 7 are each formed of an elastic member for preventing a short circuit of oil movement. Seals 19a and 19b are attached.

  As shown in FIG. 1, the tapered tip of the outer ring 8a of the triport type constant velocity universal joint 8 is connected to the inner ring 9b of the fixed type constant velocity universal joint 9 by spline coupling, and the outer ring 9a is connected to the shaft by spline coupling. It is connected to the bevel gear 11a through the joint 10. The outer ring 9 a of the fixed type constant velocity universal joint 9 is rotatably supported by a bearing case 20 by an angular ball bearing 21, and the angular ball bearing 21 is preloaded by tightening a nut 22. The bearing case 20 is fixed to a knuckle case 24 described later by bolting.

  The bevel gear 11b meshed with the bevel gear 11a is fixed to the flange of the shaft coupling 12 by bolting. In addition, shims 23a and 23b are respectively bitten on the back sides of the bevel gears 11a and 11b, and by changing the thicknesses of these, the contact degree of the teeth of the bevel gears 11a and 11b is adjusted.

  The shaft coupling 12 is connected to the hub shaft 3 by spline coupling, and the hub shaft 3 is rotatably supported by a knuckle case 24 by an angular ball bearing 25. The angular ball bearing 25 is preloaded by a nut 26 that tightens the shaft coupling 12. Further, the wheel 2 and the brake rotor 27 are fixed to the hub shaft 3 with bolts 28.

  The suspension mechanism adopts an independent suspension type double wishbone type. Pillow balls 29 are fixed to upper and lower arms 24 a and 24 b provided on the knuckle case 24, and base ends thereof are connected to the vehicle body 1. Further, the upper arm 30 and the lower arm 31 are rotatably connected to the pillow balls 29 by a concave spherical surface provided at the tip thereof. The axis connecting the spherical centers of the pillow balls 29 determines the kingpin angle. Further, the coil springs 32 constituting the suspension mechanism are interposed between the downward surface of the vehicle body 1 and the upper surface of the lower arm 31 via the trays 33, respectively.

  FIGS. 3A and 3B show a first modification of the telescopic part having the shock absorber function. This modification employs a double offset type constant velocity universal joint 34 which is a sliding type constant velocity universal joint, and an inner ring 34b is connected to the tip of the rotary shaft 7 by spline coupling. Is transmitted to the outer ring 34a via balls 34d held in the cage 34c in which the centers of the inner and outer spherical surfaces are offset. The ball 34d is slidable in the axial direction of the outer ring 34a, and an expansion / contraction part is formed between the rotating shaft 7 and the outer ring 34a. The orifice units 18a, 18b, and 18c for exhibiting the shock absorber function are the same as those in the embodiment.

  4 (a) and 4 (b) show a second modification of the telescopic part having the shock absorber function. This modification employs a ball spline 35 instead of a sliding constant velocity universal joint, and an inner ring 35b is connected to the tip of the rotating shaft 7 by spline coupling, and the rotation of the rotating shaft 7 is connected to the outer ring 35a. It is transmitted to the outer ring 35a via balls 35c arranged between the spline grooves of the inner ring 35b. The ball 35c is slidable in the axial direction of the outer ring 35a, and an expansion / contraction part is formed between the rotating shaft 7 and the outer ring 35a. Also in this modified example, the orifice units 18a, 18b, and 18c are the same as those in the embodiment.

  In the above-described embodiment and its modification, the triport type constant velocity universal joint and the double offset type constant velocity universal joint are employed as the sliding type constant velocity universal joint that forms the expansion and contraction part having the shock absorber function. A type of sliding constant velocity universal joint can also be adopted.

  In the above-described embodiment, a double wishbone type suspension mechanism is used, but any type of suspension mechanism can be used. The brake mechanism is not limited to the disc brake using the brake rotor of the embodiment, and a drum brake can also be adopted.

Longitudinal sectional view showing an embodiment of an automobile motor drive system a is an enlarged longitudinal sectional view showing the stretchable portion of FIG. 1, and b is a sectional view taken along line IIb-IIb of a. a is a longitudinal sectional view showing a first modification of FIG. 2, and b is a sectional view taken along line IIIb-IIIb of a. a is a longitudinal sectional view showing a second modification of FIG. 2, and b is a sectional view taken along line IVb-IVb of a.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Car body 2 Wheel 2a Tire 3 Hub shaft 4 Motor 4a Output shaft 4b Rubber mount 5 Shaft joint 6 Fixed constant velocity universal joint 6a Outer ring 6b Inner ring 7 Rotating shaft 7a 鍔 8 Triport type constant velocity universal joint 8a Outer ring 8b Trunnion 8c Needle 8d Roller 9 Fixed type constant velocity universal joint 9a Outer ring 9b Inner ring 10 Shaft joint 11a, 11b Bevel gear 12 Shaft joint 13 Angular ball bearing 14 Nut 15 Lid 16 Slide bearing 17 Seal 18 Orifice 18a, 18b, 18c Orifice unit 19a, 19b Seal 20 Bearing case 21 Angular ball bearing 22 Nut 23a, 23b Shim 24 Knuckle case 24a, 24b Arm 25 Angular ball bearing 26 Nut 27 Brake rotor 28 Bolt 29 Pillow ball 30 Upper arm 31 Lower arm 32 Coil spring 33 Receptacle 34 Double offset type constant velocity universal joint 34a Outer ring 34b Inner ring 34c Cage 34d Ball 35 Ball spline 35a Outer ring 35b Inner ring 35c Ball

Claims (8)

  In a motor drive system of an automobile having a motor in which an axle of a wheel is suspended on a vehicle body via a suspension mechanism and drives the axle, the motor is attached to the vehicle body side, and the output shaft of the motor and the axle are expanded and contracted. A motor drive system for an automobile, which is connected by a drive force transmission mechanism having a portion.   The motor drive system for an automobile according to claim 1, wherein the motor is installed above the upper surface of the tire of the wheel.   The motor drive system for an automobile according to claim 1 or 2, wherein the expansion / contraction part of the driving force transmission mechanism has a shock absorber function.   4. The motor drive system for an automobile according to claim 3, wherein a sliding type constant velocity universal joint is used for the expansion / contraction portion having the shock absorber function.   4. The motor drive system for an automobile according to claim 3, wherein a ball spline is used for the expansion / contraction portion having the shock absorber function.   The motor drive system for an automobile according to any one of claims 1 to 5, wherein both ends of the expansion / contraction part of the driving force transmission mechanism are supported by a constant velocity universal joint.   The motor drive system for an automobile according to any one of claims 1 to 6, wherein a gear reduction device is provided in the drive force transmission mechanism.   The motor drive system for an automobile according to any one of claims 1 to 7, wherein the motor is individually provided for all wheels.

Images