JP2003194135A - Bumper spring for vehicular suspension - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure that can effectively suppress or prevent generation of abnormal sound, in a bumper spring for a vehicular suspension arranged in a dust cover comprising a hard sleeve. <P>SOLUTION: A hard resin ring 36 is arranged on an outer circumference of a cylindrical bumper spring body 30 formed from urethane foam, and at a height with radially outer projection beyond the resin ring 36, and adjacently to the resin ring 36, a plurality of protrusions 40 integrally protruding from the bumper spring body 30 are spaced at give intervals along the circumference of the bumper spring body 30. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bumper spring for a vehicle suspension, and more particularly to a vehicle suspension that is disposed under an extrapolation state with respect to a piston rod of a shock absorber to elastically limit the working stroke of the shock absorber. Bumper springs.

[0002]

BACKGROUND ART Conventionally, in a shock absorber that constitutes a vehicle suspension, generally, a cylindrical pumper spring formed of an elastic body made of a material such as rubber or urethane foam is externally inserted to a piston rod, When a large load is input, the bumper spring connects the cylinder of the shock absorber (absorber plate) and the member on the vehicle body side or the wheel side (upper support) to which the piston rod of the shock absorber is attached. During this period, the working stroke of the shock absorber is elastically limited by being compressed and deformed in the axial direction.

By the way, the bumper spring has
In order to achieve both good riding comfort and steering stability of the vehicle, a nonlinear spring characteristic is required, which is soft when the stroke of the shock absorber is small and hard enough when the stroke is large, and to other members such as dust covers. It is required to secure a sufficiently large working stroke of the shock absorber while preventing interference.

For this reason, in the past, it has been practically used in the practice of Shokai 60-751.
As disclosed in Japanese Patent Publication No. 09, Japanese Utility Model Laid-Open No. 61-203807, Japanese Patent Laid-Open No. 6-229437, etc., a restraining ring made of synthetic resin or the like is provided on the outer peripheral surface of the bumper spring body. By restricting the outward bulging deformation of the bumper spring body, the deformation of the bumper spring body is restricted when a large load is input, while realizing a hard spring characteristic and preventing buffering of other members, A bumper spring has been proposed in which the deformation stroke amount of the bumper spring body is increased to realize a low spring characteristic when a small load is input.

Further, from the viewpoint of importance of riding comfort in recent years, in order to soften the contact when the bumper spring and the shock absorber plate come into contact with each other, for example, Japanese Utility Model Laid-Open No. 62-1100.
As disclosed in Japanese Patent Publication No. 6 and the like, there is proposed a bumper spring having a structure in which urethane foam is used as the material of the bumper spring body instead of rubber.
Even in that case, from the viewpoint of durability against the arrangement of the above-mentioned restraint ring or the contact (collision) of the absorber plate of the shock absorber, such a bumper spring should be provided near the end on the shock absorber side. A structure in which a hard ring made of resin or the like is fitted is also under study.

On the other hand, as is apparent from Japanese Patent Laid-Open No. 2000-88031, an externally mounted bumper spring is provided to prevent the entry of muddy water or dust into the oil seal portion between the cylinder and piston rod of the shock absorber. Is provided with a thin-walled cylindrical dust cover that surrounds the bumper spring so as to cover the piston rod, and such a dust cover is generally made of rubber. . Then,
Due to the increase in the number of small cars in recent years, there is a tendency to adopt a design in which the space for disposing such a dust cover is as compact as possible. Therefore, if the dust cover is made of rubber, the rigidity itself is weak. In addition to that, the narrow space causes the problem that the dust cover interferes with the peripheral members.
As disclosed in Japanese Patent Laid-Open No. 10-331899, etc., a hard cylindrical member (sleeve) made of a rigid material such as iron has begun to be used as the dust cover.

However, in the case where the dust cover is made of a hard sleeve, the shock absorber is provided with a bumper spring having a restraining ring or a hard ring on the outer peripheral portion as described above. When a large compressive load in the axial direction is applied to the bumper spring by externally inserting it onto the piston rod of the shock absorber and impacting the absorber plate of the shock absorber, the bumper spring falls down diagonally in the axial direction and becomes a meandering shape. It has been clarified that it deforms and abuts or collides with the inner surface of the hard dust cover, which causes a new problem that abnormal noise is generated.

Moreover, the problem of such deformation of the bumper spring in the axial direction and the generation of abnormal noise is more remarkable when it is made of urethane foam material because it is a material softer than rubber. It is a serious problem. Further, even when a hard ring is arranged at the end of the bumper spring, the above-mentioned deformation is likely to occur, and therefore the problem of noise generation is remarkable as in the above case.

[0009]

[MEANS FOR SOLVING PROBLEMS] The present invention has been made in view of such circumstances, and a problem to be solved by the present invention is a bumper spring for a vehicle suspension arranged in a dust cover made of a hard sleeve. The object of the present invention is to provide a structure capable of effectively suppressing or preventing the generation of abnormal noise.

[0010]

In order to solve such a problem, a bumper spring for a vehicle suspension according to the present invention is externally arranged on a piston rod of a shock absorber forming a vehicle suspension in a dust cover made of a hard sleeve. , A bumper spring that elastically limits the operation stroke of the shock absorber by abutting the absorber plate on the shock absorber, and on the outer peripheral portion of the tubular bumper spring body formed of an elastic body, While the hard ring is disposed, a protrusion integrally protruding from the bumper spring main body at a height that projects radially outward from the hard ring is provided adjacent to the hard ring and the bumper spring. The feature is that it is installed intermittently or continuously in the circumferential direction of the main body. It is an.

In short, in the bumper spring for a vehicle suspension according to the present invention, a protrusion having a height that projects radially outward from a hard ring provided on the outer peripheral portion of the tubular bumper spring body. Since the part is integrally provided on the bumper spring body, the bumper spring body is deformed by the load input from the shock absorber, is displaced radially outward, and contacts the inner surface of the dust cover. However, even if there is a possibility that the hard ring will come into contact with the inner surface of the dust cover prior to the hard ring, contact or collision of the hard ring with the inner surface of the dust cover can be effectively avoided or Can be suppressed, so that the generation of abnormal noise due to the collision between them can be advantageously prevented or mitigated. It is.

According to one of the preferred embodiments of the bumper spring for a vehicle suspension according to the present invention, the hard ring is arranged in proximity to the end of the bumper spring body located on the shock absorber side. The provided configuration will be adopted. In particular, in such an arrangement of the hard ring, since the contact with the inner surface of the dust cover is likely to occur, the present invention can be advantageously applied and its characteristics can be effectively exhibited.

According to another preferred aspect of the present invention, a curl portion extending in the circumferential direction is formed on the outer peripheral surface of the bumper spring, and peaks and troughs are arranged alternately in the axial direction. A structure in which the hard ring and the protrusion are provided in one of the peaks is advantageously adopted. In this way, by forming the peaks and troughs in the axial direction of the bumper spring body, when the operation stroke at the initial stage of contact of the shock absorber is small,
A soft spring characteristic can be effectively exhibited, and by providing a hard ring and a protrusion on one of the peaks, the contact of the hard ring with the inner surface of the dust cover is reduced. Such protrusions can be effectively prevented or suppressed.

Further, in the present invention, the structure in which the hard ring is arranged at the one of the peaks closest to the absorber plate of the shock absorber is advantageously adopted. Become.

Further, according to another preferred embodiment of the bumper spring for a vehicle suspension according to the present invention, the hard ring is arranged at a position closer to the absorber plate of the shock absorber than the protrusion. Therefore, it is also possible to adopt a method in which the bumper spring body is molded in the presence of a hard ring, that is, the so-called insert molding operation is not used, but only the bumper spring body is molded and then the hard ring is assembled to it. Therefore, it is possible to improve the assemblability of the bumper spring body and the hard ring.

Further, in the present invention, the elastic body forming the bumper spring body is preferably urethane foam, and by using the bumper spring body made of such a material, a soft spring characteristic is advantageous. And the advantageous characteristics as a bumper spring can be easily exerted, while the soft spring characteristic makes it easy to cause the abnormal noise caused by the contact or contact with the inner surface of the dust cover. However, the presence of the protrusion according to the present invention can effectively suppress or prevent the protrusion.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, in order to more specifically clarify the present invention, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows a form in which a specific example of a bumper spring for a vehicle suspension according to the present invention is mounted on a suspension mechanism of an automobile. Here, 10 is a bumper spring, and this bumper spring 10 is externally inserted and arranged on the protruding tip side portion of the piston rod 14 of the shock absorber 12, and the tip end portion of the piston rod 14 is arranged. An upper support 16 is attached to the. The piston rod 14 can be attached to the body of the automobile through the attachment plate 18 of the upper support 16 in the same manner as in the conventional case. Further, in a form hanging from the mounting plate 18 of the upper support 16, a cylindrical dust cover surrounds the bumper spring 10 and further covers at least an upper portion of the shock absorber 12, so that the dust cover is fixed. It is set up.

More specifically, the shock absorber 12
Is a well-known structure, and is a piston rod that protrudes from a cylinder 22 in which oil or the like is enclosed and an absorber plate 24 that is an end plate of the cylinder 22 and that is capable of protruding / retracting in the axial direction. Although not shown, the cylinder 22 is attached to a suspension arm or the like on the base side (the end opposite to the protruding side of the piston rod 14) side, while the piston rod 14 is provided. Is mounted on the body side via the mounting plate 18 of the upper support 16 so that the piston rod 14 is axially actuated in accordance with the swing of the suspension arm so that the piston rod 14 can be mounted on the suspension mechanism of the automobile. Has become. A male screw portion is provided at the projecting tip of the piston rod 14, and a tightening nut 26 for attaching the piston rod 14 to the body is screwed. Further, one end of a cylindrical iron-made dust cover 20 is welded and attached to the lower surface of the attachment plate 18 of the upper support 16, while the dust cover 20 is at least attached to the shock absorber 12. Although not shown, a coil spring is interposed between the hanging end of the dust cover 20 and the base part of the shock absorber 12 so as to cover the protruding side part of the piston rod 14. It is the same as the conventional one.

The bumper spring 10 is arranged in such a form that it is externally inserted into the protruding tip side portion of the piston rod 14 of the shock absorber 12. The bumper spring 10 includes a thick-walled cylindrical bumper spring main body 30 formed of an elastic body made of urethane foam (polyurethane foam), and a holding metal fitting 3 fitted to an end portion of the upper support 16 side.
2 and. Here, the holding metal fitting 32 has a shape in which a cylindrical portion is provided on the inner peripheral portion of the annular plate-shaped portion, and the cylindrical portion is fitted into the inner diameter portion of the bumper spring body 30 as shown in the figure. As a result, it is assembled and is externally fitted to the piston rod 14.

The bumper spring body 30 has a substantially thick cylindrical shape as a whole, and the diameter of the inner hole of the bumper spring body 30 is the piston rod 14 of the shock absorber 12.
The outer diameter of the shock absorber is smaller than the outer diameter of the shock absorber as it goes downward in the axial direction in the figure. It is adapted to be brought into contact with the 12 absorber plates 24. The outer peripheral surface of the bumper spring body 30 has a substantially V-shaped cross section and has a concave groove that is a concave groove extending in the circumferential direction.
However, a plurality (two in this case) are formed so as to be separated in the axial direction, and the peaks and the valleys are alternately arranged in the axial direction, and the curled portion 34 is also provided on the inner peripheral surface. A plurality of shallow-bottomed grooves extending in the circumferential direction are formed in the thick portion that is not formed, whereby the bumper spring body 30 has a substantially bellows shape. When a directional load is applied, buckling deformation is prevented, stable elastic deformation is generated in the axial direction, and stable spring characteristics can be exhibited.

Furthermore, such a bumper spring 10
A hard resin ring 36 is disposed near the end of the bumper spring body 30 located on the shock absorber 12 side. The resin ring 36 is provided from the viewpoint of adjusting the spring characteristics of the bumper spring body 30 and ensuring durability, and here, the bumper spring body 30 has a mountain portion on the lowermost end side in the drawing. It is fixedly mounted by being fitted into the circumferential groove 38 provided in the.

Then, the bumper spring body 30
2, a plurality of protrusions 40 in the shape of a long mountain extending in the axial direction and reaching the curled portion 34 are formed in the circumferential direction so as to be located immediately above the resin ring 36. The bumper spring body 30 is provided with a predetermined interval and integrally protrudes from the bumper spring body 30 at a predetermined height. It should be noted that each of the plurality of protrusions 40 has a height that projects radially outward from the resin ring 36, in other words, the diameter of the circumscribed circle of the plurality of protrusions 40 is greater than the outer diameter of the resin ring 36. Is provided at a height that also increases, and here, when a tangent line is drawn to the adjacent protrusions 40, 40, the resin ring 36 is located radially inward of the bumper spring body 30 with respect to the tangent line. The height of the protrusion 40 is adjusted so as to be positioned.

Therefore, in the bumper spring 10 having such a structure, when the shock absorber 12 pulls in the piston rod 14 to bring the absorber plate 24 into contact with the bumper spring 24 and the load is axially input, The spring body 30 is axially buckled or thrusted, and the resin ring 36 is
Even when the dust cover 20 is displaced in the left-right direction and may come into contact with or collide with the inner surface of the dust cover 20, the plurality of protrusions 40 may protrude outward in the radial direction more than the resin ring 36. Since the resin ring 36 comes into contact with the inner surface of the dust cover 20 before coming into contact with the inner surface of the dust cover 20, the displacement of the resin ring 36 is reduced. The contact with or the collision with can be effectively prevented or suppressed, and thus the generation of abnormal noise can be advantageously eliminated or suppressed.

In this way, the plurality of protrusions 4 arranged in the circumferential direction
By the presence of 0, the interference between the hard dust cover 20 and the resin ring 36 fitted in the bumper spring body 30 can be effectively suppressed or prevented, and the vehicle suspension can be made compact. It can greatly contribute to

Further, since the resin ring 36 is arranged at the outer peripheral surface position of the bumper spring main body 30 closer to the absorber plate 24 of the shock absorber 12 than the plurality of protrusions 40 arranged in the circumferential direction, The bumper spring 10 is completed if the spring body 30 is foam-molded in advance, and then the resin ring 36 is fitted into and fixed to the circumferential groove 38 provided in the foam-molded product. Therefore, such bumper spring 10 is completed. The manufacturability of 10 can be further enhanced as compared with the insert molding method in which the bumper spring body 30 is foam-molded in the presence of the resin ring 36.

The above has described in detail one typical embodiment of the present invention, which is a literal example.
It goes without saying that the present invention should not be construed as being limited to such specific examples.

For example, in the illustrated specific example, a plurality of protrusions 40 are provided on the outer peripheral surface of the bumper spring body 30.
The bumper spring body 30 is provided integrally with the bumper spring body 30 at predetermined intervals in the circumferential direction to intermittently provide circumferentially in the circumferential direction of the bumper spring body 30. It is also possible to form such a protrusion by a protrusion provided continuously in the direction. In particular, since the continuous ridge is formed over the entire circumference of the bumper spring body 30, the action of the resin ring 36 when it interferes (abuts) with the dust cover 20 is more effectively suppressed. Has features that can be mitigated.

The ridges in place of the illustrated protrusions 40 are resin rings 36 as in the arrangement of the protrusions 40 in FIG.
It is desirable to be disposed closer to the upper support 16 in the axial direction than the axial direction. This has the advantage that the force that enters the resin ring 36 through the absorber plate 24 can be easily transmitted to the upper portion of the bumper spring body 30. is doing.

Further, as the disposition position of the resin ring 36,
In the illustrated specific example, the vicinity of the end of the shock absorber 12 of the bumper spring body 30 on the absorber plate 24 side where the interference with the dust cover 20 is likely to occur is set. There is a case where it is also provided on the outer peripheral surface of the portion, and in that case, the protrusion is also provided adjacent to the resin ring 36 arranged at such an axially central portion.

Further, as the elastic body forming the bumper spring main body 30, urethane foam is used in the illustrated specific example, but any conventional rubber material may be used. The resin ring 36 may be a hard ring made of a metal material such as iron, and the dust cover 20 may be made of a hard sleeve made of a resin material or the like in addition to the metal material such as the iron material. It is also possible to use.

In addition, the shape and structure of the bumper spring body 30 can be appropriately selected, and for example, the curled portion 34 as illustrated does not necessarily have to be provided. Further, even in the case of forming such a curled portion 34, it is possible to adopt a curled portion having a cross-sectional shape such as a semicircular shape or a U shape other than the V-shaped cross section as illustrated. Therefore, as a concrete shape of the bumper spring body 30,
The present invention is not limited to the example, and it is possible to have a bellows shape over the entire length in the axial direction, or a straight tube shape without a bellows-like portion.

Although not listed one by one, the present invention is
The present invention can be carried out in a mode in which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art, and in addition, as long as such a mode does not depart from the spirit of the present invention, It goes without saying that the invention is included in the scope of the invention.

[0034]

As is apparent from the above description, in the bumper spring for a vehicle suspension according to the present invention, the bumper spring for a vehicle is adjacent to the hard ring disposed on the outer peripheral portion of the bumper spring body, and is closer to the hard ring than the hard ring. Since the protrusion protruding outward is provided integrally with the bumper spring main body, the hard ring comes into contact with or collides with a hard dust cover arranged so as to surround the bumper spring main body. However, such protrusions can be effectively prevented or suppressed,
Thus, the generation of abnormal noise caused by the interference of the hard ring with the dust cover can be advantageously eliminated or alleviated.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional explanatory view showing an example of a disposition structure of a bumper spring for a vehicle suspension as an embodiment of the present invention.

2 is a cross-sectional view taken along the line AA in FIG.

[Explanation of symbols] 10 Bumper spring 12 shock absorber 14 Piston rod 16 Upper support 18 Mounting plate 20 dust cover 22 cylinders 24 absorber plate 26 Tightening nut 30 Bumper spring body 32 retaining bracket 34 Currant 36 resin ring 38 circumferential groove 40 protrusions

Continued front page    F term (reference) 3J059 AA03 AE10 BA41 BA54 BB01                       BC06 BD01 DA16 DA18 GA02                       GA03                 3J066 AA07 AA22 AA26 BA01 BB01                       BC01 BD05 BE01                 3J069 AA50 CC06 DD26

Claims (6)

[Claims] 1. A dust cover formed of a hard sleeve is externally arranged on a piston rod of a shock absorber that constitutes a vehicle suspension, and an operating stroke of the shock absorber is elastically caused by contact of an absorber plate of the shock absorber. The bumper spring is configured to be limited to the above, and a hard ring is arranged on the outer peripheral portion of the tubular bumper spring body formed of an elastic body, while protruding outward in the radial direction from the hard ring. At a height that the bumper spring main body integrally protrudes from the bumper spring main body, adjacent to the hard ring, intermittently or continuously in the circumferential direction of the bumper spring main body. Bumper spring for suspension. 2. The bumper spring for a vehicle suspension according to claim 1, wherein the hard ring is arranged in proximity to an end portion of the bumper spring body located on the shock absorber side. 3. The outer peripheral surface of the bumper spring body,
A curled portion extending in the circumferential direction is formed, and a mountain portion and a valley portion are alternately arranged in the axial direction, and the hard ring and the protrusion are provided in one of the mountain portions. The bumper spring for vehicle suspension according to claim 1 or 2. 4. The bumper spring for a vehicle suspension according to claim 3, wherein the hard ring is arranged at a portion of the peak portion that is closest to the absorber plate of the shock absorber. 5. The bumper spring for a vehicle suspension according to claim 1, wherein the hard ring is arranged at a position closer to the absorber plate of the shock absorber than the protrusion. 6. The bumper spring for a vehicle suspension according to claim 1, wherein the elastic body is urethane foam.