JP2005153557A - Motor driving system for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure ride comfort and traveling performance, without impairment of wide flexibility in a motor installing position that is a merit of motor driving, concerning an automobile motor-driving a wheel which is not steered. <P>SOLUTION: In a driving force transmitting device, a motor 3 for driving a hub shaft 4 of a wheel adopting a suspension of a trailing arm system wherein positional relation between a trailing arm 5 and a knuckle 9 is not changed is attached to a vehicle body 1 side, and driving force of the motor 3 is transmitted to a hub shaft 4. A fixed type constant velocity universal joint 10 positioning a joint center on a rotation shaft 5a of the trailing arm 5 is provided, thereby making a driving force transmitting direction smoothly follow a rotating direction of the trailing arm 5 at a joint center of the fixed type constant velocity universal joint 10. Ride comfort and traveling performance can be ensured without impairment of wide flexibility in the motor installing position that is a merit of motor driving. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  Automobiles equipped with motors that drive wheel axles include electric vehicles that are driven only by motors, and so-called hybrid vehicles that use different engines and motors. In addition, suspensions for suspending the axle on the vehicle body include an independent suspension system for independently suspending the axle of each wheel connected to the universal joint, and an axle suspension system for integrally suspending the axles of the left and right wheels including the differential device. A non-steering wheel is used that does not change the positional relationship between the rotating arm and the knuckle, such as a trailing arm method.

  The motor drive system of an automobile equipped with a drive motor and a suspension is a so-called in-wheel type system in which a motor and a gear reduction mechanism are directly connected to an axle and these motor and gear reduction mechanism are suspended by a suspension together with the axle. (For example, refer to Patent Document 1) Or, by connecting a motor and a transmission to a differential device, the drive shaft on the differential device side and the drive shaft on the wheel side (axle) can be freely set as in the conventional engine drive type. There exists what was connected with the joint (for example, refer to patent documents 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 has the advantage that a differential device and a universal joint are not required, and the drive force transmission device can be slimmed. However, the motor and the gear reduction mechanism are suspended together with the axle. Since it is suspended, the unsprung weight increases, and there is a problem that 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.

  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 system so that the unsprung weight does not increase and the hybrid vehicle is Can be applied, but a wide degree of freedom in the installation position of the drive source (motor), which is a merit of the 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.

  Therefore, an object of the present invention is to ensure riding comfort and running performance without impairing a wide degree of freedom of a motor installation position, which is a merit of motor driving, for an automobile that drives motors of wheels that are not steered. .

  In order to solve the above-described problems, the present invention includes a motor that drives a wheel axle, and a suspension that suspends the motor-driven axle on a vehicle body so that the positional relationship between the rotating arm and the knuckle does not change. In a motor drive system for an automobile adopting the above, the joint center is located on the rotation shaft of the rotation arm in the drive force transmission device that attaches the motor to the vehicle body side and transmits the drive force of the motor to the axle. A configuration with a constant velocity universal joint was adopted.

  In other words, a motor that drives the axle of a wheel that employs a suspension that does not change the positional relationship between the pivoting arm and the knuckle is attached to the vehicle body, and the driving force transmission device that transmits the driving force of this motor to the axle is rotated. By providing a constant velocity universal joint with the joint center located on the pivot axis of the arm, the driving force transmission direction can smoothly follow the rotation direction of the rotary arm at the joint center of the rotatable constant velocity universal joint. The ride comfort and running performance can be secured without losing the wide flexibility of the motor installation position, which is the merit of motor drive.

  The driving force transmission device may include a gear transmission mechanism.

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

  In the motor drive system for an automobile according to the present invention, a motor for driving an axle of a wheel that employs a suspension in which the positional relationship between the rotating arm and the knuckle does not change is attached to the vehicle body, and the driving force of the motor is transmitted to the axle. Since the constant velocity universal joint whose joint center is located on the rotation axis of the rotation arm is provided in the driving force transmission device, the driving force transmission direction of the rotation arm is fixed at the joint center of the constant velocity universal joint. Riding comfort and running performance can be ensured without losing a wide degree of freedom of the motor installation position, which is a merit of motor driving, by smoothly following the rotation direction. In addition, it is possible to prevent the motor from directly receiving shocks due to road surface irregularities or the like, and to improve the mounting environment.

  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 and 2 show a first embodiment. This motor drive system of an automobile is driven by motors 3 having left and right wheels 1 attached to the body 2 side, and a hub shaft 4 that is an axle of each wheel 1 has a trailing arm 5 and a coil spring 6. The suspension is suspended on the vehicle body 2 by a trailing arm type suspension using the oil damper 7. The left and right trailing arms 5 are connected by a torsion beam 8. Each wheel 1 is a rear wheel that is not steered, and the positional relationship between the trailing arm 5 as a rotating arm and the knuckle 9 that rotatably supports the hub shaft 4 does not change.

  Each of the motors 3 is equipped with a speed reduction mechanism using planetary gears, and its output shaft 3a is directed backward in a direction crossing the hub shaft 4 and attached to the vehicle body 2 via a rubber mount 3b. . The driving force of each motor 3 is transmitted from the output shaft 3a to the hub shaft 4 through a gear transmission mechanism using a fixed type constant velocity universal joint 10, a rotating shaft 11, and bevel gears 12a and 12b. Yes. Instead of providing a reduction mechanism on the motor 3 side, a reduction ratio can be provided between the bevel gears 12a and 12b.

  As shown in FIG. 3, the output shaft 3a of the motor 3 is connected to the outer ring 10a of the fixed constant velocity universal joint 10 by flange connection, and one end of the rotary shaft 11 is connected to the inner ring 10b by spline connection. . The other end of the rotary shaft 11 is connected to the bevel gear 12a by spline coupling, and the bevel gear 12b meshing with the bevel gear 12a at a right angle is coupled to the hub shaft 4 via a spline-coupled shaft coupling 13. The bevel gear 12 a and the hub shaft 4 are rotatably supported by the knuckle 9 by angular ball bearings 14 and 15, respectively. The wheel 1 and the brake rotor 16 are fixed to the hub shaft 4 by bolts 17.

  The left and right trailing arms 5 are rotatably supported on a coaxial rotation shaft 5 a via rubber bushes 18, and are joints of a fixed type constant velocity universal joint 10 that transmits the driving force of each motor 3. The center is located on the rotation shaft 5 a of the left and right trailing arms 5. Therefore, the rotating shaft 11 connected to the inner ring 10b of the fixed type constant velocity universal joint 10 smoothly follows the rotating direction of the trailing arm 5 and is supported by the knuckle 9 whose positional relationship with the trailing arm 5 does not change. A driving force is transmitted to each of the bevel gears 12 a and 12 b and the hub shaft 4.

  FIG. 4 shows a second embodiment. The motor drive system of this automobile has the same basic configuration as that of the first embodiment, and uses a sliding constant velocity universal joint 20 to connect the output shaft 3a of the motor 3 and the rotary shaft 11. Only the difference. This sliding type constant velocity universal joint 20 is a double offset type constant velocity universal joint, and a joint center between an outer ring 20a flange-coupled to the output shaft 3a and an inner ring 20b spline-coupled to one end of the rotary shaft 11. Thus, the ball 20d is held by the cage 20c in which the centers of the spherical surfaces of the inner and outer diameters are offset. The ball 20d can slide in the axial direction of the outer ring 20a, but does not slide much in this embodiment. Other types of sliding constant velocity universal joints such as tripod type constant velocity universal joints can also be used.

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

The notch top view which shows the motor drive system of the motor vehicle of 1st Embodiment Sectional view along the line II-II in FIG. FIG. 1 is an enlarged plan view showing the main part of FIG. The notched top view which expands and shows the principal part of the motor drive system of the motor vehicle of 2nd Embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel 2 Car body 3 Motor 3a Output shaft 3b Rubber mount 4 Hub shaft 5 Trailing arm 5a Rotating shaft 6 Coil spring 7 Oil damper 8 Torsion beam 9 Knuckle 10 Fixed constant velocity universal joint 10a Outer ring 10b Inner ring 11 Rotating shafts 12a and 12b Bevel gear 13 Shaft coupling 14, 15 Angular contact ball bearing 16 Brake rotor 17 Bolt 18 Rubber bush 20 Sliding constant velocity universal joint 20a Outer ring 20b Inner ring 20c Cage 20d Ball

Claims (3)

  A motor drive system for an automobile, which includes a motor for driving a wheel axle, and employs a suspension that suspends the motor-driven axle on a vehicle body so that a positional relationship between a rotating arm and a knuckle does not change. Is mounted on the vehicle body side, and a constant velocity universal joint having a joint center located on the rotation shaft of the rotation arm is provided in the driving force transmission device that transmits the driving force of the motor to the axle. Automotive motor drive system.   The motor drive system for an automobile according to claim 1, wherein the driving force transmission device includes a gear transmission mechanism.   The motor drive system for an automobile according to claim 1 or 2, wherein a gear reduction mechanism is provided in the driving force transmission device.

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