JPH03121915A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To equalize stress acting on the surface of a coil spring, and simplify and stabilize a spring end support part in a coil spring type suspension device for an automobile by supporting both body and axle sides of the coil spring in such a way as to be freely rotatable about an axial line toward the center axis of the spring. CONSTITUTION:The body side end 31 and axle side end 32 of a coil spring 26 constituting a suspension device 10 are so supported as to be freely rotatable about an axial line A toward a coil center axis C via end support mechanisms 35 and 36 of the same construction respectively installed on the first and second members 27 and 28. Namely, the end support mechanism 35 has a pair of support bodies 41 ana 42 on the base body 40 thereof, and an axis 43 having an axial line A toward the coil center axis C in a freely rotatable state. In addition, a joint member 50 is fitted to the aforesaid axis 43, thereby supporting the body side coil spring end dl. The other end support mechanism 36 is similarly constructed. According to the aforesaid construction, stress acting on the surface of the coil spring 26 can be equalized, and the end support thereof can be simplified and stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle suspension system used in a suspension system of a vehicle such as an automobile.

[Prior art] Compression coil springs used in vehicle suspension springs are
As illustrated in FIG. 5, the terminal waistband parts 2 and 3 of the wire 1 are restrained by spring seats 4 and 5, respectively, and a vertical load is applied via the spring seats 4 and 5. .

When the coil spring with the end turn portion 2°3 restrained by the spring seat 4.5 is compressed in the axial direction,
Since a so-called eccentric load acts, the surface stress of the wire 1 does not take a negative shape in the axial direction of the wire 1 (direction a in the figure) but becomes a waveform.

As an example, when we investigated the distribution state of the maximum shear stress on the surface of the inner diameter side of the coil of a coil spring in a compressed state, we found that
It was found that the waveform distribution was as shown in Figure 6.

[Problem to be solved by the invention] If the stress distribution is wavy like in a conventional coil spring, the stress peak value on the surface of the wire becomes high, and a coil spring that can cope with this stress peak value is a wire. The diameter becomes thicker.

In addition, the coil spring with improved terminal support structure and (7)
Japanese Unexamined Patent Publication No. 60-85003 has been proposed.

In this prior art, one end of the strand is supported rotatably in all directions by a support element such as a steel ball.
The aim is to reduce the bending stress that occurs at the ends of the strands. However, when the ends of the strands are rotatably supported in all directions as in this prior art, the structure of the end support portion of the strands becomes complicated, and the support tends to become unstable.

Therefore, an object of the present invention is to provide a vehicle suspension coil spring that can nearly equalize the stress generated on the surface of the suspension coil spring, and that can stably support the end of the coil spring with a relatively simple support mechanism. The purpose of the present invention is to provide a suspension system.

[Means for Solving the Problems] The present inventors investigated the stress distribution that occurs when a load is applied to a suspension coil spring, and surprisingly found that the ends of the wires could be rotated only in one direction. It has been found that the stress distribution along the axis of the strands approaches equalization by simply supporting the strands freely.

From this point of view, the present invention, which was developed to achieve the above object, consists of a first part (4) located on the vehicle body side;
A suspension device comprising a second member displaceable relative to the member and located on the axle side, and a coil spring provided in a compressed state between the first member and the second member, a first terminal support mechanism that is provided on the first member and rotatably supports one end of the strand of the coil spring about an axis extending toward the coil central axis; and a second terminal support mechanism that is provided at the coil spring and rotatably supports the other end of the strand of the coil spring around the axis of the coil toward the central axis of the coil. .

[Function] Both ends of the coil spring in the suspension system of the present invention are rotatably supported by a first terminal support mechanism and a second terminal support mechanism, respectively, around an axis extending toward the coil center axis. There is. The sprung load of the vehicle acts in a direction that compresses the coil spring. When a load is applied to this coil spring, the wire is bent and both ends of the wire rotate in the above direction, thereby flattening the stress distribution of the wire.

[Example] The first example of the present invention will be described below with reference to Figures 1 to 6.
This will be explained with reference to the figures.

Strut type vehicle suspension system 1 shown in FIG.
0 is provided between a member (referred to as a vehicle body component) 11 that constitutes a part of the vehicle body and a hub carrier 12 .

The hub carrier 12 has an axle 14 that supports the wheel 13.
is provided.

The lower part of the hub carrier 12 is connected to the vehicle body component H20 via a ball joint 17, a lower arm 18, and a pivot 19. The lower arm 18 can rotate vertically about a pivot 19.

The suspension system 10 of this embodiment includes a damper 25 and a compression coil spring 2 mounted so as to surround the outer periphery of the damper 25.
6. This coil spring 26 includes a first member 27 located on the heavy object side and a second member 27 located on the axle side.
8. The damper 25, like a well-known shock absorber, contains fluid such as hydraulic oil and damping force generating means therein. This damper 25 is expandable and retractable in the axial direction, and is configured to attenuate the expansion and contraction movement in the axial direction by the damping force generating means. An example of the first member 27 located on the upper end side of the damper 25 is an upper mount, which is rotatable around the C-axis.

A first member 27 is provided at an axially intermediate portion of the damper 25 .

The coil spring 26 is formed by winding a wire 30 made of spring steel in a spiral shape. The wire 30 may be solid,
It doesn't matter if it's hollow. The element 4130 has an end 31 located on the upper side in the figure and an end 32 located on the lower side in the figure. And one end 31 is a first terminal support mechanism 35
It is supported by the first member 27 by. other end 3
2 is attached to the second part It by the second terminal support mechanism 36
It is supported by 28. The terminal support mechanisms 35 and 36 have the same configuration.

As shown in FIGS. 4 and 5 as a representative of one terminal support mechanism 35, a pair of supports 41 and 41 are provided on the base body 40. The base body 40 is fixed to the first member 35 by suitable means such as screwing or welding. Note that the support body 41.41 is directly attached to the first member 2 without using the base body 40.
It may be fixed to 7.

The shaft 43 is inserted into the hole 42.42 made in the support 41.41.
is inserted rotatably. This axis 43 is along the axis A that goes toward the coil center axis C.

A joint member 50 is rotatably supported by the shaft 43. The joint member 50 includes a cylindrical base portion 51 into which the shaft 43 is inserted, and a wire holding portion 52 that protrudes in the radial direction of the base portion 51. The wire holding portion 52 includes a hole 53 into which the end portion 31 of the wire is inserted. The end portion 31 is formed into a flat shape, and a hole 5 into which the end portion 31 is inserted is formed.
3 is shaped in such a way that the end portion 31 can be just fitted into it. By doing this, the end portion 31 of the strand
Relative rotation of the cable wire holding portion 52 around the axis is prevented. The end portion 31 may be fixed by being press-fitted into the hole 53, or the end portion 31 may be welded to the cable holding portion 52.

The second terminal support mechanism 36 is also configured similarly to the support mechanism 35 described above.

The sprung load applied to the suspension system 10 acts in a direction that compresses the coil spring 26, and the load is elastically supported by the repulsive force of the coil spring 26. The coil spring 26 bends depending on the magnitude of the load, and the end 3 of the strand
1 and 32 respectively rotate around an axis A directed toward the coil center axis C. Coil spring 26 that operates in this way
When the stress distribution (maximum shear stress on the inner diameter side of the coil) was investigated, it was confirmed that the stress was almost flat as shown in FIG. In this case, the maximum stress value is the conventional product (
(see Figure 15), so it is less likely to break than conventional products. Further, if the average stress is made equal to that of the conventional product, the wire diameter of the cable wire 30 can be reduced, leading to a reduction in the weight of the coil spring 26.

Moreover, since the suspension device 10 of this embodiment can support the coil spring 26 by the terminal support mechanisms 35 and 36, which are more compact than conventional spring seats, mounting the coil spring 26 is also advantageous in terms of securing space.

Note that the ends 31 and 32 of the cable wire are connected to the joint member 50.5.
0, a serration or a spline is provided on the end 31 as shown in FIG. It may be provided in the portion 52.

Joint member 6 of terminal support mechanism 35 shown in FIG.
0, a cylindrical strand holder 52 is provided on a U-shaped leg 61, and the end 31 of the strand is inserted into the strand holder 52 in a non-rotatable manner as in the previous embodiment.

The terminal support mechanism 35 shown in FIG. 9 has a rod 65 welded to the end 31 of the wire 30 in a direction perpendicular to the wire 30, and
This rod 65 is rotatably supported in the holes 42 and 42 of the supports 41 and 41. The structure of each of the above embodiments may be adopted for the second terminal support mechanism 36.

In the strut type suspension device 70 shown in FIG. 10, a damper 25 and a coil spring 26 are installed separately. In this case, a coil spring 26 is provided between the vehicle body component 71 and the lower arm 18.

The upper end 31 of the wire 30 of the coil spring 26 is connected to the first support member 72 by the first terminal support mechanism 35, and the lower end 32 of the wire 30 is connected to the second support member 73 by the second terminal support mechanism 36. connected to.

The end portions 31 and 32 of the cable wire are supported rotatably around an axis A extending toward the coil central axis C, and this axis A is parallel to the pivot axis 19 of the lower arm 18, as in the previous embodiment. It is set up like this. According to such a configuration, when the lower arm 18 rotates in the vertical direction, the ends 31 and 32 of the strands can rotate around the axis A that is parallel to one pivot. Therefore, when the lower arm 18 rotates in the vertical direction, it is possible to prevent the coil spring 26 from curving inward as shown by the two-dot chain line 0 in the drawing (occurrence of so-called body bending). This allows the coil spring 26 to be deflected almost straight.

In the double wishbone type suspension system 8 shown in FIG. The upper part of the hub carrier 12 is supported by an upper arm 81 on a vehicle body component 82.The lower arm 18 and the upper 7'-m 81 are
Each can be rotated vertically around a pivot 19°83. The upper end portion 31 of the wire 30 of the coil spring 26 is supported by the first support member 27 by the same first terminal support mechanism 35 as in each of the embodiments described above. The lower end portion 32 of the wire 30 is supported by the second member 28 by a second terminal support mechanism 36 .

In the double wishbone type suspension system 90 shown in FIG. 12, a damper 25 and a coil spring 26 are installed separately, and the coil spring 26 is installed between the lower arm 18 and the vehicle body component 71. ing. The ends 31 and 32 of the wire are as in each of the above embodiments,
The coil is rotatably supported around an axis A directed toward the center axis C of the coil, and this axis A is aligned with the pivot 19 of the lower arm 18 and the pivot 83 of the upper arm 81. There is. In this case as well, the first
Similarly to the embodiment shown in FIG. 0, the occurrence of body bending of the coil spring 26 can be suppressed.

13 and 14 show yet another embodiment of the invention. Both ends 31 of the wire 30 of the coil spring 26 in this embodiment. ．． 32 is bent almost straight along its length toward the coil center axis C. These both ends 31.32 are connected to the axis A by means of terminal support mechanisms 35.36.
It is designed to be rotatably supported around the axis. The length may be set appropriately. The support members 95 and 96 of this embodiment have holes 97 and 98 into which the ends 31 and 32 of the strands are rotatably inserted. These holes 97 and 98 are along the axis A towards the central axis C of the coil. The support members 95 and 96 are located near the coil center axis C. Holes 97 are provided at the ends 31 and 32 of the wire.
．． A low friction component 99 such as a sliding bearing or an oil bushing is installed in order to smooth rotation relative to the inner surface of the shaft 98 and to reduce wear.

In this illustrated example (FIG. 13), when a compressive load is applied to the coil spring 26, the ends 31, 32 rotate around the axis A, depending on the amount of deflection of the coil spring 26. . This embodiment also makes it possible to flatten the surface stress of the coil spring 26.

[Effects of the Invention] According to the present invention, the stress distribution of the strands of the suspension coil spring can be equalized, contributing to weight reduction. Moreover, since it is only necessary to support the ends of the strands rotatably in one direction, a stable end support state can be obtained.

[Brief explanation of drawings]

1 to 6 show an embodiment of the present invention, in which FIG. 1 is a front view of the suspension device, FIG. 2 is a perspective view showing a part of the suspension device, and FIG. 3 is a perspective view of the suspension device. FIG. 4 is a perspective view showing the end of the cable and the terminal support mechanism; FIG. 5 is an exploded perspective view showing the end of the cable and the terminal support mechanism; FIG. Figures 7 to 9 are perspective views showing modified examples of the terminal support mechanism, and Figures 10 to 12 are diagrams showing different embodiments of the present invention. FIG. 14 is a front view of a suspension device showing an example, FIG. 13 is a perspective view of a suspension coil spring showing yet another embodiment of the present invention, and FIG. 15 is a sectional view showing a conventional coil spring and a spring seat, and FIG. 16 is a diagram showing stress distribution of the conventional coil spring shown in FIG. 15. 10... Suspension III, 26... Coil spring, 27.
... first member, 28 ... second member, 30 ... strand,
31... - end, 32... other end, 35.
...First terminal support mechanism, 36...Second terminal support mechanism, 50°60...Ji4 ind member, 70...Suspension device, 72...4 First support part shrine, 7 3...Second support part shrine, 80°...Suspension device, C...Coil center axis, A...Line segment toward the coil center axis.

Claims (1)

[Claims] A first member located on the vehicle body side, a second member displaceable with respect to the first member and located on the axle side, and a compressed state between the first member and the second member. A vehicle suspension system comprising a coil spring provided in the first member, wherein one end of the strand of the coil spring is rotatable about an axis directed toward the coil center axis. a first terminal support mechanism that is provided on the second member and that supports the other end of the strand of the coil spring rotatably around an axis that extends toward the coil center axis; A vehicle suspension system comprising a terminal support mechanism.