JP2000142058A - Suspension device of automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain separation of a spring seat and a crack of a beam by upward inclining the joining seat surface with a torsion beam formed on a coil spring seat joined to an end part of the torsion beam to the inside from the car width outside. SOLUTION: This device has a torsion beam 4 connected between left/right wheels and a lower spring seat 12 joined to the end part. A joining structure of the lower spring seat 12 and the torsion beam 4 is formed so that the upper edge of a rear side flange part 12c inclines upward to the inside from the car width outside to thereby restrain separation by torsional deformation of the torsion beam 4 and the occurrence of a crack by strengthening of joining strength. The occurrence of a crack is restrained by an arm part 12e extended up to a top part of the torsion beam 4 in an inside flange part 12a hardly influenced by the torsional deformation of the torsion beam 4 to enhance joining strength.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension system for an automobile, and more particularly to a torsion beam type rear suspension system.

[0002]

2. Description of the Related Art As a conventional automobile suspension device, a torsion beam connected between left and right rear wheels and a plate-like structure to allow displacement in a vehicle width direction are provided. The trailing arm has two free trailing arms, and the free end of the trailing arm is supported on the vehicle body frame via a bush, and the rear end of each trailing arm is welded to the left and right ends of the torsion beam. There is a torsion beam type rear suspension device formed by joining (see Japanese Patent Application Laid-Open No. 4-283114).

[0003] This torsion beam type rear suspension device has been mounted on a mini car or the like because of its simple structure and low cost. However, the center of the coil diameter of the coil spring is not located directly above the trailing arm or the torsion beam, but the torsion beam. The position of the coil spring is lowered by offsetting it from the vehicle, which has the advantage that the floor height can be lowered and the rear luggage space can be widened. The demand for is increasing.

[0004]

However, according to the technique disclosed in the above publication, when a spring seat or its bracket is formed at a corner portion, the effective effective length of the trailing arm is shortened, so that the torsional elasticity is increased and the riding comfort is increased. Gets worse. For this reason, it is conceivable to lengthen the trailing arm by an amount corresponding to the shortened effective length, but this will deteriorate the layout. In addition, it is conceivable to lengthen the torsion beam, but in this case, the torsional elasticity of the torsion beam becomes too low and the running stability deteriorates,
It is necessary to increase the strength of the portion where the torsional stress of the torsion beam is concentrated, which may increase the cost due to the increase in weight.

In a suspension device in which the center of the coil diameter of the coil spring is offset with respect to the torsion beam, the torsion beam twists to separate the joint surface between the spring seat and the torsion beam. There is a problem that stress is concentrated and a crack is generated at a joint surface of the torsion beam.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to suppress the separation of a spring sheet and the crack of a beam due to the concentration of torsional stress of a torsion beam, and to maintain a suspension performance of an automobile at a light weight and at a low cost. It is to provide.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve the object, a vehicle suspension device according to the present invention comprises a torsion beam type rear suspension device and a torsion beam connected between left and right wheels. And a coil spring seat joined to an end of the torsion beam, and a joint seat surface formed on the coil spring seat with the torsion beam is formed to be inclined upward from the vehicle width outside to the inside.

Preferably, the coil spring seat has a box shape having a rear flange portion erected at a rear end in a vehicle longitudinal direction and inner and outer flange portions erected at both ends in a vehicle width direction. At least the rear surface of the rear flange portion is joined to the front surface of the torsion beam in the vehicle longitudinal direction.

[0009] Preferably, the coil spring seat is cantilevered by the torsion beam only on the rear surface of the rear flange portion.

Preferably, the inner flange portion has an arm portion extending to the top of the torsion beam.

[0011] Preferably, the outer flange portion is joined to a side portion of the torsion beam.

Preferably, the vehicle further includes a plate-shaped trailing arm extending from the torsion beam to a predetermined position in the longitudinal direction of the vehicle body and rotatably supported at the predetermined position. The trailing arm is provided at a predetermined interval in the vehicle width direction.

Preferably, the apparatus further comprises a damper whose lower end is rotatably supported at the predetermined interval.

[0014]

As described above, according to the first aspect of the present invention, the joint seat surface formed on the coil spring seat with the torsion beam is formed so as to be inclined upward from the vehicle width outside to the inside. It is possible to suppress the separation of the spring seat outside the vehicle width and the crack of the beam due to the concentration of the torsional stress of the torsion beam, and it is possible to maintain the suspension performance lightly and inexpensively.

According to the second aspect of the present invention, the coil spring seat has a box having a rear flange portion erected at the rear end in the vehicle longitudinal direction and inner and outer flange portions erected at both ends in the vehicle width direction. Being a body shape, at least the rear surface of the rear flange portion is joined to the front surface of the torsion beam in the vehicle longitudinal direction, so that the coil spring seat can be arranged offset with respect to the torsion beam, and the floor height is reduced, and Separation of the rear flange portion and cracking of the beam due to concentration of torsional stress of the torsion beam can be suppressed.

According to the third aspect of the present invention, the coil spring seat is cantileveredly supported by the torsion beam only on the back surface of the rear flange portion, so that the inner or outer flange portion is joined to increase the strength. The generation of cracks in the beam due to the concentration of torsional stress of the torsion beam can be suppressed.

According to the fourth aspect of the present invention, since the inner flange portion has the arm portion extending to the top of the torsion beam, the concentration of the torsional stress of the torsion beam is suppressed even when the joining strength of the coil spring seat is increased. be able to.

According to the fifth aspect of the present invention, since the outer flange portion is joined to the side surface portion of the torsion beam, the joint strength of the outer flange portion where the torsion stress of the torsion beam tends to concentrate is suppressed, and the beam is cracked. Can be suppressed.

According to the sixth aspect of the present invention, since the coil spring seat is provided at a predetermined distance from the trailing arm in the vehicle width direction, the biasing force of the coil spring acts in the peeling direction of the coil spring seat. Also, since the concentration of torsional stress can be suppressed, there is no need to increase the bonding strength, and the suspension performance can be maintained at a light weight and at low cost.

According to the seventh aspect of the present invention, further comprising a damper having a lower end pivotally supported at a predetermined interval so that the biasing force of the coil spring and the damping force of the damper can be reduced in the direction of peeling the coil spring sheet. Therefore, the concentration of torsional stress can be suppressed, so that it is not necessary to increase the bonding strength, and the suspension performance can be maintained at a light weight and at low cost.

[0021]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a plan view of a vehicle suspension device according to the present embodiment. FIG. 2 is a plan view showing details near the end of the torsion beam. FIG. 3 is a side view showing details near the end of the torsion beam. FIG. 4 is an enlarged view of FIG.

As shown in FIGS. 1 to 4, the present embodiment is exemplified by a plate-shaped trailing arm 1 having elasticity that allows torsion inward of the vehicle width, and a trailing arm 1 extending in the vehicle width direction. A torsion beam 4 (a beam having elasticity in a torsion direction) connected between the left and right wheels 2 and 3, and a torsion beam type rear in which a coil diameter center of a coil spring is offset from an axial center of the torsion beam 4. It is a suspension device.

The torsion beam 4 is inverted U which opens downward.
It has a U-shaped cross section. The trailing arm 1 extends in the front-rear direction of the vehicle body, and its front end 1a is rotatably supported by a floor arm 7 via a support bush 5 and a bracket 6, and its rear end 1b is open rearward when viewed from the side. It is formed in a concave shape, and this concave portion is joined to the front surface slightly inside from both ends of the torsion beam 4 by welding or the like to form a connecting portion 8 between the trailing arm 1 and the torsion beam 4 (see FIG. 3).

Wheel support members 9 are joined to both left and right end portions of the torsion beam 4, and a wheel support 11 having a spindle 10 is bolted up on an upper end surface of the wheel support member 9, and a brake mechanism is provided on the spindle 10. The wheels (that is, the rear wheels) 2 and 3 are attached via these.

A substantially box-shaped lower spring seat 12 is joined to the front surface of the torsion beam 4 by welding or the like at a predetermined distance L (see FIG. 4) from the trailing arm 1 inward of the vehicle width. An upper spring seat 13 is joined to the lower surface of the floor frame 7 by welding or the like so as to face the seat 12, and a coil spring 14 is stretched between the upper and lower spring seats 12, 13.

As shown in FIG. 4, a damper 15 is disposed in the space of the predetermined interval L so as to be substantially parallel to the vertical surface of the trailing arm 1.

The upper end 15a of the damper 15 is supported on the outer surface of the floor frame 7 by a mounting member 16. The lower end 15b of the damper 15 is the trailing arm 1
And the side surface of the lower spring seat 12. The lower end 15 b of the damper 15 is inserted into a bush 17 through a rod 18, and the rod 18 is inserted into a hole 19 formed in the lower end of the trailing arm 1 and a rod mounting piece 12 a provided integrally with the lower spring seat 12. The threaded portion 18a of the rod 18 is inserted through the hole 20 formed.
A nut 21 is screwed into the nut, and the rod 18 is rigidly fixed to the trailing arm 1 and the rod mounting piece 12a of the lower spring seat 12, so that the rod 18 is rotatably supported. Further, the damper 15 is rotatable around a longitudinal axis of the damper 15 orthogonal to the rotation axis of the bush 17, that is, rotatable in the direction of arrow a shown in FIG.

That is, the lower end portion 15b of the damper 15 is disposed within the predetermined interval L, and is rotatably supported across the trailing arm 1 and the lower spring seat 12. A collar 22 is provided on the inner surface of the lower end portion 15b and on the outer peripheral portion of the rod 18 from the trailing arm 1 to the rod mounting piece 12a.

A bump stopper rubber 23 is provided between the torsion beam 4 and the floor frame 7 in the vicinity of the joint of the lower spring seat 12 to the torsion beam 4. The upper support bush 24 extends over one of the floor frames 7 (the upper floor frame 7 in FIG. 1) located behind the torsion beam 4 and the rear surface of the end of the torsion beam 4 remote from the one floor frame 7. A lateral link 26 is stretched in a slant manner via the lower support bush 25 and the lower support bush 25, thereby regulating unnecessary movement of the trailing arm 1 in the vehicle width direction. In FIG. 1, F indicates the front direction of the vehicle body, and R indicates the rear direction of the vehicle body.

As shown in FIG. 4, the lower spring seat 12 has inner flanges in the vertical direction at the rear end in the vehicle longitudinal direction and both ends in the vehicle width direction so that the upper part thereof and the front end in the vehicle longitudinal direction are opened. Part 12a, outer flange part 12b,
The rear flange portion 12c is formed in a box shape in which each is erected,
The rear end edges of the inner and outer flange portions 12a and 12b and the back surface of the rear flange portion 12c are joined along the front surface of the torsion beam 4 in the vehicle longitudinal direction. Note that only the rear flange portion 12c may be joined to the torsion beam 4 to be cantilevered.

The coil spring seat 12 is cantilevered by the torsion beam 4 by an inner flange portion 12a, an outer flange portion 12b, and a rear flange portion 12c.
The inner flange portion 12a has an arm portion 12e extending to the top of the torsion beam 4.

In the suspension device of the present embodiment, the end of the torsion beam 4 is displaced almost directly (slightly inward of the vehicle width) while twisting forward when the rear wheel bounces. As a result, the trailing end 1b of the trailing arm 1 is displaced while being twisted substantially directly above (slightly inward of the vehicle width) along an arc locus with the support bush 5 as a fulcrum.

When the torsion beam 4 is twisted, the inner flange portion 1 of the lower spring seat 12 is
Since the outer flange portion 2a, the outer flange portion 12b, the rear flange portion 12c, and the arm portion 12e have a sufficient beam length against the torsion of the torsion beam 4, peeling due to torsional deformation and cracking of the torsion beam 4 due to torsional stress occur. However, since the outer flange portion 12b and the rear flange portion 12c have a short beam length with respect to the torsion of the torsion beam 4, they are easily separated by torsional deformation,
Even if the joining strength of the joining portion is increased, the torsional stress will be concentrated on the contrary, and a crack will be generated in the corresponding portion of the torsion beam 4. This problem is caused by the rear flange 12
If the upper edge of c is formed horizontally, it is likely to appear remarkably.

Further, since the lower end 15b of the damper 15 is pivotally supported between the trailing arm 1 and the lower spring seat 12, the lower spring seat 12 is attached to the lower spring seat 12 in the direction of extension of the coil spring 14 when the rear wheel bounces. The urging force and the damping force of the damper 15 act on the joint surface between the lower spring seat 12 and the torsion beam 4 as a shear force in the peeling direction. Therefore, it is necessary to increase the fatigue strength of the joint surface of the lower spring seat 12.

Therefore, in the present embodiment, the above-mentioned problem is solved by employing the joining structure described below. [First Joint Structure] FIG.
FIG. 3 is a diagram showing a first joining structure of the torsion beam 4 and a torsion beam 4. FIG. 6 is a front view of FIG.

As shown in FIGS. 5 and 6, in the first joint structure, the upper end edge of the rear flange portion 12c is formed so as to be inclined upward from the outside to the inside of the vehicle width.

With the first joint structure, it is possible to suppress separation due to torsional deformation of the torsion beam 4 at the joint portion of the rear flange portion 12c, and generation of cracks due to increased joining strength to the torsion beam 4. Further, by forming the arm portion 12e extending to the top of the torsion beam 4 on the inner flange portion 12a which is less affected by the torsional deformation of the torsion beam 4, it is possible to suppress the occurrence of cracks and the like and increase the bonding strength.

As a result, it is not necessary to improve the joining strength (welding strength) of the lower spring seat, and it is possible to reduce the unsprung weight without increasing the rigidity excessively, and to improve running stability. Becomes [Second Joining Structure] FIG.
FIG. 4 is a diagram showing a second joint structure between the torsion beam 4 and the torsion beam 4.

As shown in FIG. 7, the second joint structure has an edge portion 4a bent substantially horizontally inside the torsion beam 4.
In particular, a portion where torsional stress is likely to concentrate, that is, a portion corresponding to the inner flange portion 12a and the arm portion 12e of the lower spring seat 12 is formed to be expanded as compared with the other portions, and the strength of the torsion beam 4 against torsional stress is formed. Is increasing. The extension 4b may be formed at a location corresponding to the outer flange 12b.

In the second joint structure, the strength of the torsion beam 4 at a portion where the torsional stress tends to concentrate can be increased.

[Third Joint Structure] FIG. 8 is a view showing a third joint structure between the lower spring seat 12 and the torsion beam 4. FIG. 9 is a sectional view taken along line XX of FIG.

As shown in FIGS. 8 and 9, the third joint structure is torsional deformation of the torsion beam 4 in the vehicle width direction at a position corresponding to the rear end edge of the inner flange portion 12 a and the joint surface on the front surface of the torsion beam 4. Is formed, and a concave portion of the uneven portion 4c forms a non-welded portion with the inner flange portion 12a.
The uneven portion 4c may be formed at a position corresponding to the joint surface of the outer flange portion 12a.

In the third joining structure, the uneven portion 4c
Thus, torsional deformation of the torsion beam 4 where the torsional stress tends to be concentrated can be allowed, so that cracking due to the torsion deformation of the torsion beam 4 and the increase in bonding strength can be suppressed.

Instead of forming the uneven portion 4c, a gap that is not welded is formed at the joint between the torsion beam 4 and the inner flange portion 12a (or the outer flange portion 12b) to allow torsion deformation of the torsion beam 4. You may.

It should be noted that the present invention can be applied to a modification or change of the above embodiment without departing from the spirit thereof.

For example, the first to third joining structures may be appropriately combined.

[0048]

[Brief description of the drawings]

FIG. 1 is a plan view of a vehicle suspension device according to an embodiment.

FIG. 2 is a plan view showing details in the vicinity of an end of a torsion beam.

FIG. 3 is a side view showing details near the end of the torsion beam.

FIG. 4 is an enlarged view of FIG. 2;

FIG. 5 is a view showing a first joining structure of the lower spring seat 12 and the torsion beam 4.

FIG. 6 is a front view of FIG. 5;

FIG. 7 is a view showing a second joining structure of the lower spring seat 12 and the torsion beam 4.

FIG. 8 is a view showing a third joining structure of the lower spring seat 12 and the torsion beam 4.

FIG. 9 is a sectional view taken along line XX of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Trailing arm 2, 3 Wheel 4 Torsion beam 8 Connecting part 12 Lower spring seat 15 Damper 17 Bush L Interval

Claims (7)

[Claims] 1. A torsion beam type rear suspension device, comprising: a torsion beam connected between left and right wheels; and a coil spring seat joined to an end of the torsion beam, wherein the torsion beam is formed on the coil spring seat. A suspension device for an automobile, characterized in that a joint seat surface with the vehicle is formed so as to be inclined upward from the outside of the vehicle width to the inside. 2. The coil spring seat is formed in a box shape having a rear flange portion erected at a rear end in a vehicle longitudinal direction and inner and outer flange portions erected at both ends in a vehicle width direction. The vehicle suspension device according to claim 1, wherein a rear surface of the rear flange portion is joined to a front surface of the torsion beam in a vehicle longitudinal direction. 3. The vehicle suspension device according to claim 1, wherein the coil spring seat is cantilevered by the torsion beam only on the back surface of the rear flange portion. 4. The suspension apparatus according to claim 1, wherein the inner flange has an arm extending to a top of the torsion beam. 5. The suspension apparatus according to claim 4, wherein the outer flange portion is joined to a side surface of the torsion beam. 6. A plate-shaped trailing arm extending from the torsion beam to a predetermined position in the longitudinal direction of the vehicle body and rotatably supported at the predetermined position, further comprising: The vehicle suspension device according to any one of claims 1 to 5, wherein the vehicle suspension device is provided at a predetermined distance from the vehicle in the vehicle width direction. 7. The vehicle suspension device according to claim 6, further comprising a damper whose lower end is rotatably supported at the predetermined interval.