JPS6341211A - Suspension for vehicle - Google Patents

Abstract

PURPOSE:To ensure the minimum ground clearance of a suspension and to improve the rigidity, by arranging two transverse leaf springs having opposite ends in lateral direction fixed to a supporting member for rear wheels with an internal in the longitudinal direction of a body. CONSTITUTION:Leaf springs 3, 4 extending in the lateral direction of a body are fixed respectively to the front and rear frames 2a, 2b and arranged in parallel in the lateral direction with a predetermined interval longer than the width of motor units 5, 6 at the positions of same height. Then rear wheels 1A, 1B are secured to the output shafts of the motor units 5, 6 secured to the opposite end sections of the leaf springs 3, 4. Consequently, the rigidity against the motion of the rear wheels 1A, 1B in back and forth direction and yawing direction is improved and the ground clearance of the suspension is ensured sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a suspension device for a vehicle, and more particularly to a suspension device equipped with a transverse leaf spring.

(Prior Art) In the past, various types of metal leaf springs have been widely used in vehicle suspension systems, and these leaf springs are generally arranged in the longitudinal direction of the vehicle body.

By the way, Automotive Engineering Handbook Volume 11 Chapter 4, 4
- Fig. 26 of 3.2 shows an independent suspension system in which a pair of metal leaf springs are arranged vertically at a predetermined interval.

(Problem to be Solved by the Invention) In the above-mentioned suspension device equipped with a pair of upper and lower transverse leaf springs, the movement of the wheel in the camber direction cannot be restrained unless a predetermined interval is left between the upper and lower leaf springs. Although it is not possible to obtain the necessary rigidity, the distance from the road surface to the lower leaf spring becomes very small if there is sufficient spacing, so it is necessary to ensure the minimum ground clearance specified by various regulations (laws and regulations). In the case of a wheel motor type electric vehicle, the wheel motor is large in diameter, so it is difficult to apply the above suspension device to this type of electric vehicle.
Since the pair of leaf springs are located above and below and in the same position in the longitudinal direction of the vehicle, they lack the rigidity to restrain the movement of the wheels in the longitudinal direction and in the yaw direction (toe-in/toe-out direction), so they are used as separate suspension arms and tension ronds. There are problems such as the need to provide a pair of functioning left and right links.

(Means for Solving the Problems) A suspension device for a vehicle according to the present invention is a suspension device for a vehicle equipped with a transverse leaf spring, which extends in the vehicle width direction and is attached to rear wheel support members at both ends. Two transverse leaf springs are arranged at a predetermined distance in the longitudinal direction of the vehicle body.

Note that, if necessary, the transverse leaf spring may be constructed of an FRP leaf spring.

(Function) In the vehicle suspension device according to the present invention, 2
Since the transverse leaf springs are arranged at predetermined intervals in the longitudinal direction of the vehicle body, a sufficient distance from the road surface to the leaf springs is ensured. The rigidity that restrains the movement of the wheel in the longitudinal direction and the rigidity that restrains the movement of the wheel in the lateral direction are high.

(Effects of the Invention) According to the vehicle suspension device according to the present invention, as explained above, the ground clearance from the road surface to the suspension device can be sufficiently large, and the rigidity against the longitudinal movement of the wheel and the yaw direction of the wheel can be increased. Effects such as a suspension device with high rigidity against motion and a suspension device applicable to wheel motor type electric vehicles and the like can be obtained.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a suspension device for an electric vehicle will be described below with reference to the drawings.

(First Example) This example relates to a suspension device that suspends the rear wheels of an electric vehicle on the vehicle body, and the rear wheels IA and IB as driving wheels are driven based on FIGS. 1 to 3 below. The wheel motor type drive device and the rear wheel suspension device will be explained, and the other configurations are the same as those of a general electric vehicle, so the explanation will be omitted.

Arrow F in the figure indicates the front, and the front frame 2a and rear frame 2b of the frame 2, which has a cross shape in plan view and is fixed to the vehicle body.
FRP leaf springs 3 and 4 extending in the vehicle width direction are installed at the center of the span, respectively, and a left motor unit 5 is installed at the left end of the front leaf spring 3 and the left end of the carrier leaf spring 4. A right motor unit 6 is attached to the right end of the leaf spring 3 and the right end of the leaf spring 4, and the left rear wheel IA is attached to the output shaft of the left motor unit 5, and the right rear wheel IA is attached to the output shaft of the right motor unit 6. The wheels IB are fixed to each other, the front side of the left motor unit 5 is connected to the vehicle body via an oil damper 7, and the front side of the right motor unit 6 is connected to the vehicle body via an oil damper 8.

The frame 2 has a pair of mounting arms 2c extending left and right, respectively.
2d, a front frame 2a extending horizontally to the front, and a rear frame 2b extending horizontally to the rear. A spring insertion hole is formed in the vicinity of the lower end of the front frame 2a in the vehicle width direction, and the front leaf spring 3, which is sandwiched between a pair of upper and lower reinforcing metal elastic plates 9, is inserted into this spring insertion hole. The center part is inserted and fixed. Similarly, a pair of upper and lower reinforcing metal elastic plates 9 are provided in the spring insertion holes of the rear frame 2b.
The central part of the span of the chaleaf spring 4 is inserted through and fixed.

Both of the above leaf springs 3 and 4 are made of FRP (fiber reinforced plastic) mainly made of glass fiber, have a predetermined width and thickness, and are gently curved in a camber shape. The springs 4 are arranged at the same height in parallel to the vehicle width direction with a predetermined interval greater than the width of the motor units 5 and 6 in the front and rear, and this allows the rear wheels IA and IB to be moved in the toe-in and toe-out directions (in the yaw direction). ) degrees of freedom are elastically constrained.

In order to connect the left and right ends of the front leaf spring 3 to the front lower part of the motor case 10 of the motor units 5 and 6, the front lower part of the motor case IO is provided with a support shaft part II.
are integrally and horizontally protruded forward, and the cylindrical portion of the connecting fitting 12 is externally fitted onto the support shaft portion 11 via an elastic bushing, and the elastic bushing is adhesively fixed to the support shaft portion 11 and the cylindrical portion, A pair of upper and lower clamping parts 12a on the inner side of the connecting fitting 12
The outer ends of the front leaf springs 3 are sandwiched between them, and these are strongly adhered and fixed with fastening bolts 3.

The structure for connecting the left and right ends of the rear leaf spring 4 to the upper rear side of the motor case 10 of the motor units 5 and 6 is also the same as described above.

Furthermore, the lower end portions of the left and right oil dampers 7 and 8 are connected to the vicinity of the outer end of the front side of the corresponding motor case 10 via a bushing, and each of the left and right oil dampers 7 and 8 is The upper end portion is connected to the vehicle body via a pair of upper and lower elastic bodies 14.

The left and right motor units 5 and 6 are similar to the motor unit described in the applicant's previous application (Utility Application No. 60-201917), and the structure thereof will be briefly explained.

Each motor unit 5, 6 is configured as follows.

That is, an electric motor is housed in the motor case IO, a disk plate with a cooling fan fixed to the inner end of its output shaft on the vehicle center side is fixed, and a caliper is provided to press the outer circumference of the disk plate. A planetary gear type speed reducer is connected to the outer end of the output shaft of the motor, and its shaft portion integral with the carrier is fixed to the wheel disk 15. In the reduction gear described above, a sun gear is provided on the output shaft of the motor, and the internal gear is fixed to the motor case 10 side.

In this way, the left and right rear wheels IA and IB are fixed coaxially to the electric motors of the motor units 5 and 6, and are rotationally driven by the rotational driving force from the electric motors via the reducer. .

In the above electric vehicle, each of the rear wheels IA-IB and the motor units 5 and 6 connected thereto are suspended on the vehicle body via the front and rear leaf springs 3 and 4, the frame 2, and the oil dampers 7 and 8. The position of the rear wheels IA and IB in the vehicle width direction is elastically restrained by the front and rear leaf springs 3 and 4, and the position of each rear wheel IA and IB in the front and rear direction is restrained by the front and rear leaf springs 3 and 4. The vertical movement of IA-IB is elastically damped by front and rear leaf springs 3 and 4 and oil dampers 7 and 8.

Furthermore, the degree of freedom in one direction of each rear wheel IA and IB is restrained by the front and rear leaf springs 3 and 4.
The degree of freedom in the camber direction is mainly restricted by the oil dampers 7 and 8.

Low-frequency vibrations propagating from the road surface to the left and right rear wheels IA-IB are absorbed by the pair of front and rear leaf springs 3 and 4, so the strut is an oil damper for shock absorption that functions as a link without a coil spring. 7
・It is only necessary to provide 8.

In addition, since the FRP leaf springs 3 and 4 have high-frequency vibration absorption characteristics, high-frequency vibrations generated from the electric motor are effectively absorbed by the leaf springs 3 and 4.

In the parts where the leaf springs 3 and 4 are attached to the front frame 2a and the rear frame 2b, the leaf springs 3 and 4 are reinforced with a pair of upper and lower elastic plates 9, which alleviates local stress and improves durability. I will do it.

In the above embodiment, the front and rear leaf springs 3 and 4 were each made up of one leaf spring, but each of the front and rear leaf springs 3 and 4 was made up of a pair of left and right leaf springs, with each inner end It may be fixed to the front frame 2a or the rear frame 2b.

Note that the leaf springs 3 and 4 mentioned above do not necessarily have a constant thickness.
It is not necessary to have a constant width, and modifications such as making it thicker or wider at the center of the span may be applied.

The leaf springs 3 and 4 may be made of an FRP material other than the above-mentioned glass fibers, which is mainly made of strong synthetic resin fibers such as carbon fibers, high-tensile metal fibers, or the like.

(Second Embodiment) Next, a second embodiment of the present invention will be described based on FIGS. 4 and 5.

In this embodiment, leaf springs made of the same material and having a different shape from the leaf springs 3 and 4 are used, and a pair of upper lateral links 20 are provided on the left and right sides in place of the oil dampers 7 and 8. This is different from the first embodiment in this point.

That is, both the front leaf spring 3A and the rear leaf spring 4A have a substantially dogleg shape in plan view, and the left and right rear wheels IA-IB are arranged so that the distance between the leaf springs 3A and 4A at the center of the span is maximum. They are arranged approximately symmetrically with respect to the axial center line at a predetermined interval and at the same height in the front and rear.

A fixed portion 3a parallel to the vehicle width direction that is fixed to the front frame 2a by a fixing fitting 21 is formed at the center of the span of the front leaf spring 3A, and a left half portion and a right half portion of the leaf spring 3A are are bent rearward by approximately 15 degrees at both ends of the fixed portion 3a and extend to the left and right, respectively, and their respective outer ends are connected to the corresponding motor case 10.
is connected to.

The fixed part 3a is sandwiched between the front frame 2a of the same width and the fixing fittings 21, and is fastened and fixed with bolts 22. Since the fixed part 3a is bent at both ends, the front leaf The spring 3A does not move in the vehicle width direction with respect to the vehicle body. The rear leaf spring 4A has the same shape as the front leaf spring 3A, and its fixed portion 4a is attached to the rear frame 4A in the same manner as above.
b, and both ends of the rear leaf spring 4A are connected to the corresponding motor cases 10, respectively.

Furthermore, in order to restrict the degree of freedom of the rear wheels IA and IB in the camber direction, elastic bushings are attached to the outer ends of the pair of front and rear upper lateral links 20 on the brackets 23 at the top of the outer ends of each motor case IO. The inner end portion of each upper lateral link 20 is connected to the support shaft on the vehicle body side via an elastic bushing. 1 on the left
Both the pair of upper lateral links 20 and the pair of upper lateral links 20 on the right side have a V-shape in plan view, and are inclined upward toward the center of the vehicle body. Note that the configuration other than the above is substantially the same as that of the first embodiment, so the same members are given the same reference numerals and explanations will be omitted.

In the above configuration, as described above, the distance between the front and rear leaf springs 3A and 4A at the center of the span is increased, so that the rigidity that restrains the movement of the rear wheels IA and IB in one direction is increased.

The position of the rear wheels IA and IB in the vehicle width direction is regulated by the front and rear leaf springs 3A and 4A and the upper lateral link 20, and the longitudinal position of the rear wheels IA and IB is mainly regulated by the front and rear leaf springs 3A and 4A. Ring IA
・The vertical movement of IB is carried out by the front and rear leaf springs 3A.
It is buffered by the elastic deformation of 4A and the torsional elastic deformation of the elastic bushes at both ends of upper lateral link 20, and the rear wheel IA.
Movement of the IB in one direction and in the camber direction is carried out by the front and rear leaf springs 3A and 4A and the upper lateral link 2.
0.

(Third Embodiment) As shown in FIGS. 6 and 7, this embodiment is a leaf spring 24 in which the front leaf spring 3 and the rear leaf spring 4 of the first embodiment are integrated into a V-shape in plan view.
The second embodiment operates in substantially the same manner as the first embodiment, except that the oil dampers 7 and 8 are connected to the top of the motor case 10.

The leaf spring 24 is made of FRP and is formed by integrally molding a front leaf spring part 3B, a carrier leaf spring part 4B, and a center spring part C, and the center spring part C is located between the left and right motor units 5 and 6. The center spring part C is fixed to the front frame 2a and the rear frame 2b of the frame 2 via the presser fittings 12A, and the connection part between the center spring part C and the front and rear leaf spring parts 3B and 4B is is rounded with a small curvature to alleviate stress concentration.

This leaf spring 24 has a sufficiently high rigidity at the center of the span, so it is excellent in terms of structure and strength. Note that the configuration other than the above is the same as that of the first embodiment.

(Fourth Embodiment) In this embodiment, as shown in FIGS. 8 and 9, a pair of left and right upper arms 25 each having a 7-shape in plan view are provided in place of the oil dampers 7 and 8 of the first embodiment. However, this upper arm 25 functions similarly to the upper lateral link 20 in the second embodiment.

However, the outer end of each upper arm 25 is connected to the top of the outer end of the motor case 10 via an elastic body 26, and the inner end is connected to the bracket 2 of the frame 2 via an elastic bushing.
7 by a longitudinal support shaft. Note that the other configurations are the same as those in the first embodiment.

The first to fourth embodiments described above are all cases in which the present invention is applied to a suspension device for an electric vehicle, but the present invention can also be applied to a suspension device for an ordinary engine-equipped vehicle or automobile other than the above. It goes without saying that the invention can be applied.

In that case, the leaf springs 3, 4, 3A, 4A,
24, the lower ends of the oil dampers 7 and 8, and the outer ends of the upper lateral link 20 and the upper arm 25,
It is connected to a rear wheel support member that rotatably supports the rear wheels IA and IB.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a perspective view of a rear wheel suspension device for an electric vehicle according to the first embodiment, FIG. 2 is a front view thereof, and FIG. 4 is a plan view of the rear wheel suspension device of an electric vehicle according to the second embodiment, FIG. 5 is a front view thereof, and FIG. 6 is a rear view of the electric vehicle according to the third embodiment. FIG. 7 is a plan view of the wheel suspension device, FIG. 8 is a plan view of the rear wheel suspension device of an electric vehicle according to the fourth embodiment, and FIG. 9 is a front view thereof. IA-IB...Rear wheel, 3.3A...Front leaf spring, 4.4A...Rear leaf spring, 5
・6...Motor unit, 24...Leaf spring. Figure 5 1B 1A Figure 7

Claims (2)

[Claims] (1) In a suspension system for a vehicle equipped with transverse leaf springs, two transverse leaf springs extending in the vehicle width direction and attached to rear wheel support members at both ends are spaced at a predetermined interval in the longitudinal direction of the vehicle body. A suspension device for a vehicle, characterized in that: (2) The suspension device for a vehicle according to claim 1, wherein the transverse leaf spring is a leaf spring made of FRP.