JP2005289288A - Motor driving system of automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driving system of an automobile furnished with a motor to drive an axle of a wheel, which improves mounting environment of the motor with the automobile adopting a suspension device unchanging a positional relation of a revolving arm and a knuckle as an object and extends a cabin and/or cargo compartment space without increasing unsprung weight. <P>SOLUTION: The motor 3 to drive a hub shaft 2a of a wheel 1 adopting the trailing arm type suspension device unchanging the positional relation of the trailing arm 6 and the knuckle 7, is mounted on a frame 8a of a car body 8 above an upper surface of a tire 1a, and an output shaft 3a of the motor 3 and the hub shaft 2a are connected to each other through a triport type constant velocity universal joint 4 integrally building a shock absorber mechanism in it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor drive system for an automobile that employs a suspension device that includes a motor that drives an axle of a wheel and that does not change the positional relationship between a rotating arm that supports the motor-driven wheel and a knuckle.

  There are two types of suspension systems for automobiles, one is an independent suspension system in which each wheel connected to a universal joint is independently suspended, and the other is an axle suspension system in which axles of left and right wheels including a differential device are suspended integrally. In addition, a suspension device that does not change the positional relationship between the rotating arm and the knuckle, such as a trailing arm method, is employed for the wheels that are not steered. Usually, these suspension devices incorporate a shock absorber mechanism using an oil damper or the like.

  On the other hand, in a motor drive system of an automobile that drives a wheel axle with a motor, a so-called in-wheel, in which a motor and a gear reduction mechanism are directly connected to the axle, and the motor and the gear reduction mechanism are suspended by a suspension device together with the axle. A drive shaft on the differential device side and a drive shaft on the wheel side (axle) are connected to a motor of the type (for example, see Patent Document 1) or a differential device with a motor and a transmission connected to the differential device. ) Are connected by a universal joint (for example, see Patent Document 2).

  In addition, for a special automobile such as a forklift without a suspension device, a motor is mounted downward on the vehicle body above the upper surface of the wheel tire, and a driving force transmission device having a gear reduction device and a bevel gear device is used. There is also one that drives an axle of a wheel that is rotatable around a heart (see, for example, Patent Document 3).

JP 2002-247713 (page 4-7, Fig. 1-2) JP 2003-72392 A (page 2-4, FIG. 2-3) Japanese Patent Laid-Open No. 2002-37595 (page 2-5, FIG. 1-7)

  The in-wheel type motor drive system described in Patent Document 1 does not require a differential device or a universal joint, and has the advantage that the drive force transmission device can be slimmed down and expansion of the room / loading room space can be expected. Since the gear reduction mechanism is suspended by the suspension device together with the wheels, 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 shocks due to unevenness of the road surface and the water is easily sprayed at a low position of the vehicle body.

  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 does not increase the unsprung weight by adopting the independent suspension type suspension device. There is a problem that the force transmission device becomes large and the room / loading room space cannot be expanded.

  Further, the motor drive system for special automobiles described in Patent Document 3 is not suitable for general automobiles such as passenger cars because it has neither a suspension device nor a shock absorber mechanism and thus has a poor ride comfort.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the motor installation environment and unsprung for an automobile that employs a suspension device that includes a motor that drives the axle of a wheel and that does not change the positional relationship between the rotating arm and the knuckle. It is possible to expand the room / loading space without increasing the weight.

  In order to solve the above problems, the present invention includes a motor that drives a wheel axle, and the positional relationship between a rotating arm that supports the motor-driven wheel and a knuckle that supports the wheel axle changes. In a motor drive system for an automobile that employs a suspension system, the motor is mounted on the vehicle body above the upper surface of the tire of the wheel, and the output shaft of the motor and the axle are connected by a driving force transmission device. .

  That is, a motor for driving a wheel axle that employs a suspension system in which the positional relationship between the rotating arm and the knuckle is not changed is mounted on the vehicle body above the top surface of the wheel tire, and the output shaft and axle of the motor are driven by the driving force. By connecting with a transmission device, the installation environment of the motor was improved, and the living room / loading room space could be expanded without increasing the unsprung weight.

  By integrating the shock absorber mechanism into the driving force transmission portion of the driving force transmission device, the design of the driving force transmission device and the suspension device can be made compact.

  A sliding-type constant velocity universal joint can be used for the driving force transmission portion in which the shock absorber mechanism is integrated. 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 driving force transmission unit in which the shock absorber mechanism is integrated.

  The motor attached to the vehicle body is supported so that the direction of its output shaft can be flexibly changed, and the direction of receiving the driving force transmission shaft from the output shaft side of the motor can be flexibly changed. By supporting the rotating arm in this manner, when the rotating arm rotates while the automobile travels on an uneven road surface, the driving force transmission shaft from the motor output shaft side crosses the rotating arm. It is possible to prevent the bending moment from acting on the driving force transmission portion of the driving force transmission device by allowing the change of the angle.

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

  The motor drive system for an automobile according to the present invention includes a motor for driving a wheel axle that employs a suspension device in which the positional relationship between a rotating arm and a knuckle does not change, and is mounted on the vehicle body above the upper surface of the wheel tire. Since the output shaft and the axle are connected by the driving force transmission device, the motor mounting environment can be improved, and the living room / loading space can be expanded without increasing the unsprung weight.

  By integrating the shock absorber mechanism into the driving force transmission portion of the driving force transmission device, the design of the driving force transmission device and the suspension device can be made compact.

  The motor attached to the vehicle body is supported so that the direction of its output shaft can be flexibly changed, and the direction of receiving the driving force transmission shaft from the output shaft side of the motor can be flexibly changed. By supporting the rotating arm in this manner, when the rotating arm rotates while the automobile travels on an uneven road surface, the driving force transmission shaft from the motor output shaft side crosses the rotating arm. It is possible to prevent the bending moment from acting on the driving force transmission portion of the driving force transmission device by allowing the change of the angle.

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

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show a first embodiment. As shown in FIGS. 1 and 2, the motor drive system for an automobile drives each hub shaft 2a, which is an axle of the left and right wheels 1, by a motor 3, and the driving force of each motor 3 is as follows. The torque is transmitted from the output shaft 3a to the hub shaft 2a through a triport type constant velocity universal joint 4 which is a sliding type constant velocity universal joint and a pair of meshing gears 5a and 5b. Each wheel 1 is a rear wheel that is not steered, and a knuckle 7 that supports the hub shaft 2 a is supported by a trailing arm 6 as a rotating arm of a suspension device. The positions of the trailing arm 6 and the knuckle 7 are The relationship does not change.

  Each of the motors 3 has a speed reduction mechanism using planetary gears, and the case 3b is attached to the frame 8a of the vehicle body 8 by bolting via the elastic member 9 above the upper surface of the tire 1a of the wheel 1. The direction of the output shaft 3a can be changed flexibly. The output shaft 3a is connected to the outer ring 4a of the tripod type constant velocity universal joint 4 by spline coupling. The outer ring 4a is rotatably supported by a cylindrical portion of the case 3b by a tapered roller bearing 10. The tapered roller bearing 10 is preloaded by tightening the nut 11.

  As shown in FIGS. 3 (a) and 3 (b), the triport constant velocity universal joint 4 includes a trunnion 4c in which an inner ring shaft 4b is inserted into a cylindrical outer ring 4a and splined to the tip of the inner ring shaft 4b. Further, the roller 4e is supported via a needle 4d, and the roller 4e slides in the axial direction of the outer ring 4a so that the outer ring 4a and the inner ring shaft 4b expand and contract, and the rotation of the outer ring 4a is applied to the inner ring shaft 4b. Communicated. A shaft provided at the tip of the cylindrical outer ring 4 a is splined to the output shaft 3 a of the motor 3.

  The outer ring 4 a of the tripod type constant velocity universal joint 4 is filled with oil, and one end into which the inner ring shaft 4 b is inserted is closed by a lid 12. Between the inner ring shaft 4b and the lid 12, a slide bearing 13 for guiding the axial movement of the inner ring shaft 4b accompanying sliding with the outer ring 4a is provided, and a seal 14 for preventing oil leakage is attached. . Although not shown, a gasket or the like for preventing oil leakage is attached between the outer ring 4 a and the lid 12.

  A flange is provided at the tip of the inner ring shaft 4b inserted into the outer ring 4a, and orifice units 15a, 15b, 15c forming an orifice 15 are attached between the flange and the trunnion 4c. Seals 16a and 16b are attached between the orifice unit 15a splined to the inner ring shaft 4b and the inner surface of the outer ring 4a and the flange of the inner ring shaft 4b to prevent short circuit of oil movement. Accordingly, a shock absorber mechanism is formed by restricting the movement of oil in the outer ring 4a accompanying expansion and contraction of the outer ring 4a and the inner ring shaft 4b, and the shock absorber mechanism is integrally incorporated in the driving force transmission portion.

  As shown in FIGS. 1 and 2, the inner ring shaft 4b of the triport type constant velocity universal joint 4 is connected to the gear 5a by spline coupling, and the gear 5a is supported on the knuckle 7 by the angular ball bearing 17, and the hub shaft. It meshes with a gear 5b fixed to 2a at a predetermined crossing angle. The angular ball bearing 17 is preloaded by tightening the nut 18. Note that a reduction ratio may be provided between the gears 5a and 5b instead of the motor 3 having a reduction mechanism.

  The knuckle 7 is supported by a flange member 20 attached to the tip of the trailing arm 6 via an elastic member 19, and receives a driving force transmission shaft via the tripod type constant velocity universal joint 4 from the output shaft 3 a of the motor 3. The direction can be changed flexibly. Accordingly, the case 3b of the motor 3 is attached to the frame 8a of the vehicle body 8 via the elastic member 9, and when the trailing arm 6 is rotated, the motor 3 comes from the output shaft 3a side. A change in the crossing angle between the driving force transmission shaft and the trailing arm 6 can be allowed, and a bending moment can be prevented from acting on the driving force transmission portion of the tripart type constant velocity universal joint 4 or the like.

  The hub shaft 2a is supported on the knuckle 7 by an angular ball bearing 21 via a hub 2 splined to the outer periphery of the hub shaft 2a. A wheel 1 and a brake rotor 22 for disc brake are fixed to the hub 2 with bolts 23. Yes. The angular ball bearing 21 is preloaded via the hub 2 by a nut 24 screwed onto the hub shaft 2a.

  As shown in FIG. 2, the left and right trailing arms 6 are rotatably supported by a rotating shaft 26 attached to the vehicle body 8 via rubber bushes 25 and are supported at the front ends thereof. In order to improve the followability of the tire 1a to the road surface, the tire 1a is biased downward by a coil spring (not shown).

  4 (a) and 4 (b) show a first modification of the driving force transmission unit in which the shock absorber mechanism is integrated. This modification employs a double offset type constant velocity universal joint 27, which is also a sliding type constant velocity universal joint, instead of the triport type constant velocity universal joint 4, and the outer ring 27a and the inner ring shaft 27b can be expanded and contracted. It is a thing. The front end portion of the inner ring shaft 27b is connected to the inner ring 27c by spline coupling, and the rotation of the outer ring 27a is performed on the inner ring shaft 27b via a ball 27e held on the inner ring 27c by a cage 27d in which the centers of the inner and outer diameter spherical surfaces are offset. The ball 27e slides in the axial direction of the outer ring 27a while being transmitted. The orifice units 15a, 15b, and 15c are the same as those in the embodiment.

  FIGS. 5A and 5B show a second modification of the driving force transmission unit in which the shock absorber mechanism is integrated. In this modification, a ball spline 28 is used instead of the sliding type constant velocity universal joint, and the outer ring 28a and the inner ring shaft 28b can be expanded and contracted. The tip of the inner ring shaft 28b is connected to the inner ring 28c by spline coupling, and the rotation of the outer ring 28a is transmitted to the inner ring shaft 28b via a ball 28d arranged between the spline grooves of the outer ring 28a and the inner ring 28c. 28d slides in the axial direction of the outer ring 28a. Also in this modification, the orifice units 15a, 15b, and 15c are the same as those in the embodiment.

  6 and 7 show a second embodiment. The motor drive system of this automobile has the same basic configuration as that of the first embodiment. The knuckle 7 is directly attached to the tip of the trailing arm 6, and the gear 5a is angularly attached to a separate gear case 29. The only difference is that the ball bearing 17 supports the gear case 29 and the ball bearing 30 rotatably supports the knuckle 7. Therefore, in this embodiment, the direction of receiving the driving force transmission shaft from the output shaft 3 a of the motor 3 via the tripod type constant velocity universal joint 4 can be flexibly changed by the rotation of the gear case 29.

  8 and 9 show a third embodiment. In this motor drive system of an automobile, the knuckle 7 is directly attached to the tip of the trailing arm 6, and the gear 5 a is supported by the angular ball bearing 17 on a separate gear case 32 that supports the gear 5 b by the angular ball bearing 31. Further, a separate gear case 33 is fixed with a bolt 34, and a driving force transmission shaft through the tripod type constant velocity universal joint 4 is received from the output shaft 3a of the motor 3 by the rotation of both gear cases 32 and 33 with respect to the gear 5b. The direction is changed flexibly.

  Further, in this embodiment, the hub 2 is formed integrally with the shaft, the gear 5 b is fixed to the shaft portion, and the angular ball bearing 31 that supports the gear 5 b on the gear case 32 is preloaded by the nut 35. Other parts are the same as those of the first embodiment.

  In each of the above-described embodiments and modified examples, 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 of the driving force transmission portion integrally incorporating the shock absorber mechanism. Other types of sliding constant velocity universal joints can also be adopted.

  In each of the above-described embodiments, the trailing arm type suspension device is used. However, the suspension device may be any device as long as the positional relationship between the rotating arm and the knuckle does not change. You can also. 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.

1 is a longitudinal sectional view showing a motor drive system of an automobile according to a first embodiment. Notched side view of FIG. a is an enlarged longitudinal sectional view showing the stretchable part of FIG. 1, and b is a sectional view taken along line III-III of a. a is a longitudinal sectional view showing a first modification of FIG. 3, and b is a sectional view taken along line IV-IV of a. a is a longitudinal sectional view showing a second modification of FIG. 3, and b is a sectional view taken along line VV of a. Partially omitted vertical sectional view showing a motor drive system of an automobile according to a second embodiment Notched side view of FIG. Partially omitted vertical sectional view showing a motor drive system of an automobile according to a third embodiment Notched side view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel 1a Tire 2 Hub 2a Hub shaft 3 Motor 3a Output shaft 3b Case 4 Triport type constant velocity universal joint 4a Outer ring 4b Inner ring shaft 4c Trunnion 4d Needle 4e Roller 5a, 5b Gear 6 Trailing arm 7 Knuckle 8 Car body 8a Frame 9 Elasticity Member 10 Tapered roller bearing 11 Nut 12 Lid 13 Slide bearing 14 Seal 15 Orifice 15a, 15b, 15c Orifice unit 16a, 16b Seal 17 Angular ball bearing 18 Nut 19 Elastic member 20 Flange member 21 Angular ball bearing 22 Brake rotor 23 Bolt 24 Nut 25 Rubber bush 26 Rotating shaft 27 Double offset type constant velocity universal joint 27a Outer ring 27b Inner ring shaft 27c Inner ring 27d Cage 27e Ball 28 Ball spline 28a Outer ring 28b Inner ring shaft 28c Inner ring 2 d ball 29 gear case 30 ball bearing 31 angular contact ball bearings 32, 33 the gear case 34 bolt 35 nut

Claims (6)

  In a motor drive system for an automobile that includes a motor that drives a wheel axle and that employs a suspension device that does not change the positional relationship between a rotating arm that supports the motor-driven wheel and a knuckle, the motor is connected to the wheel tire. A motor drive system for an automobile, which is mounted on a vehicle body above an upper surface and the output shaft of the motor and the axle are connected by a driving force transmission device.   The motor drive system for an automobile according to claim 1, wherein a shock absorber mechanism is integrally incorporated in a drive force transmission portion of the drive force transmission device.   The motor drive system for an automobile according to claim 2, wherein a sliding constant velocity universal joint is used for a driving force transmission unit in which the shock absorber mechanism is integrated.   3. The motor drive system for an automobile according to claim 2, wherein a ball spline is used for a driving force transmission unit in which the shock absorber mechanism is integrated.   The motor attached to the vehicle body is supported so that the direction of its output shaft can be flexibly changed, and the direction of receiving the driving force transmission shaft from the output shaft side of the motor can be flexibly changed. The motor drive system for an automobile according to any one of claims 1 to 4, wherein the motor drive system is supported by the rotating arm.   The motor drive system for an automobile according to any one of claims 1 to 4, wherein a gear reduction mechanism is provided in the drive force transmission device.

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