JPH0842624A - Bumper spring - Google Patents

Abstract

(57) [Summary] [Object] To provide a bumper spring that does not generate abnormal noise when the opposite end surfaces of a cylinder come into contact with each other and can prevent the cylinder from biting under a heavy load. An end portion of a bumper spring 1 facing and abutting a facing end surface 22a of a cylinder 22 is provided with a ring-shaped flat surface 15 having an outer diameter smaller than an outer diameter of the facing end surface 22a of the cylinder 22 and an axis from the flat surface 15. A plurality of projecting ridges 1 each having a tapered surface 16a that projects in the radial direction, extends in the radial direction, and increases in the axial projection amount toward the outer peripheral side.
6 and.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bumper spring used as a stopper for a shock absorber in a vehicle suspension system.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 3 and 4, in a vehicle suspension device, a piston rod 21 is coaxially attached to the outer periphery of the piston rod 21.
A bumper spring 5 is used that restricts the relative movement between the piston rod 21 and the cylinder 22 by being compressed in the axial direction between the tip end of the cylinder 22 and the facing end surface 22a of the cylinder 22. The bumper spring 5 shown as the conventional example 1 is formed of rubber into a cylindrical shape, and the end portion that faces and abuts the facing end surface 22a of the cylinder 22 is a ring-shaped flat surface 55.

In addition, as shown in FIGS. 5 and 6 as the second conventional example, an end portion which faces and abuts the facing end surface 22a of the cylinder 22 has a flat surface 65 formed in the same manner as in the first conventional example.
A plurality of hemispherical projections 6 projecting from the flat surface 65 in the axial direction
A bumper spring 6 including 5a is also known (Japanese Patent Laid-Open No. 62-35128).

[0004]

However, the bumper spring 5 of the prior art example 1 faces the cylinder 22 when it is axially compressed between the tip end portion of the piston rod 21 and the facing end surface of the cylinder 22. There is a problem that abnormal noise (hit sound) is generated when the end face 22a comes into contact.

On the other hand, the bumper spring 6 of the above-mentioned conventional example 2
Although no abnormal noise is generated, unless the outer peripheral diameter of the opposing end surface of the cylinder 22 is sufficiently larger than the outer peripheral diameter of the flat surface 65 of the bumper spring 6, the end portion of the cylinder 22 will be damaged when a large load is applied. There is a problem that the bumper spring 6 bites into the inner hole 61 of the bumper spring 6 and the effective stopper function of the bumper spring 6 cannot be obtained.

The present invention has been devised in view of the above problems. A bumper spring that does not generate abnormal noise when the opposite end surfaces of the cylinder come into contact with each other and can prevent the cylinder from biting under a heavy load. It is an issue to be solved to provide.

[0007]

A bumper spring according to the present invention for solving the above-mentioned problems is coaxially attached to the outer circumference of a piston rod, and is axially arranged between a tip end portion of the piston rod and a facing end surface of a cylinder. In a rubber cylindrical bumper spring that restricts relative movement between the piston rod and the cylinder by being compressed, an end portion of the bumper spring that opposes and abuts an opposing end surface of the cylinder is an opposing end surface of the cylinder. Has a ring-shaped flat surface having an outer diameter smaller than the outer diameter, and a tapered surface projecting in the axial direction from the flat surface and extending in the radial direction and inclined so that the axial projection amount increases toward the outer peripheral side. It is characterized by comprising a plurality of ridges.

[0008]

In the bumper spring of the present invention, when the piston rod and the cylinder relatively move relatively in the direction of compressing the bumper spring, the ridges provided at the ends of the bumper spring facing the cylinder are brought into contact with the opposite end surface of the cylinder. Abut. As a result, the ridge portion having the tapered surface that extends in the radial direction and inclines so that the amount of projection in the axial direction increases toward the outer peripheral side is such that the tapered surface sequentially faces the opposite end surface of the cylinder from the outer peripheral side to the inner peripheral side. It is compressed while making contact with. At this time, the compressed portion of the ridge bulges in the centrifugal direction and also bulges in the space portions on the flat surfaces formed on both sides in the circumferential direction of the ridge portion. The bulging is suppressed by the bulging in both sides in the circumferential direction and does not become so large. Further, a larger compressive force acts on the ridge portion toward the outer peripheral side, and since the area of the tapered surface of the ridge portion that abuts on the opposite end surface of the cylinder increases in the centripetal direction, it acts on the ridge portion. The slip resistance in the centrifugal direction increases as the compressive force increases. Therefore, such a synergistic action reduces the risk that the cylinder will bite into the inner hole of the bumper spring.

In the bumper spring of the present invention, no abnormal noise is generated when the opposite end faces of the cylinder come into contact with each other. This is considered to be because the contact area is small because the surface that contacts the opposite end surface of the cylinder is only the tapered surface of the ridge, and the inclined tapered surface smoothly contacts with a time lag.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a portion of the bumper spring according to this embodiment, which corresponds to line II in FIG. 2, and FIG. 2 is a bottom view of the bumper spring according to this embodiment. The bumper spring 1 of the present embodiment is formed in a cylindrical shape having an inner hole 11 into which the piston rod 21 is inserted, and is integrally formed by vulcanizing rubber.
The upper end portion 12 of the bumper spring 1 is a portion fixedly held by the piston rod 21 inserted into the inner hole 11.
A central portion 13 adjacent below the upper end portion 12 is formed in a bellows shape in which large diameter portions and small diameter portions are alternately repeated.

Then, at the center of the lower end portion 14 adjacent to the lower portion of the central portion 13, the facing end surface 22a of the cylinder 22 is formed.
A ring-shaped flat surface 15 having an outer peripheral diameter smaller than the outer peripheral diameter of the facing end surface 22a and a plurality of (12 in this embodiment) axially projecting from the flat surface and extending in the radial direction. The ridge portion 16 is provided. The ridge portion 16 has a tapered surface 16a that is inclined so that the amount of protrusion in the axial direction increases toward the outer peripheral side. In addition,
A bellows cylindrical dust cover (not shown) extending downward so as to cover the cylinder 22 is integrally provided at the lower end peripheral edge portion of the lower end portion 14.

The bumper spring 1 of the present embodiment having the above-described structure is coaxially attached to the outer periphery of the tip end portion of the piston rod 21 in the shock absorber of the vehicle suspension device for use. In this case, a metal plate 24 having a mounting hole 24a having a diameter smaller than that of the inner hole 11 is attached to the upper end 12 of the bumper spring 1, and a tip portion of the piston rod 21 in which a spacer 25 is previously attached to the inner hole 11 of the bumper spring 1. Is inserted so that the male screw portion 21a formed at the tip thereof projects from the mounting hole 24a of the metal plate 24, and the nut 26 is tightened to the male screw portion 21a, whereby the bumper spring 1 is mounted.

In the suspension device thus mounted, the piston rod 21 is used when the vehicle is running.
When the cylinder 22 and the cylinder 22 relatively move in the direction of compressing the bumper spring 1, the bumper spring 1 is axially compressed between the tip end portion of the piston rod 21 and the opposed end surface 22a of the cylinder 22 to cause the piston rod 21 to move. The relative movement between the cylinder 22 and the cylinder 22 is restricted. At this time, the protruding portion 16 of the lower end portion 14 of the bumper spring 1 contacts the facing end surface 22 a of the cylinder 22. This allows
The ridge portion 16 having the tapered surface 16a that extends in the radial direction and is inclined so that the amount of protrusion in the axial direction increases toward the outer peripheral side is such that the tapered surface 16a faces the cylinder 22 sequentially from the outer peripheral side toward the inner peripheral side. It is compressed while contacting the end face 22a.

At this time, the compressed portion of the ridge 16 swells in the centrifugal direction and also bulges in the space portions on the flat surfaces 15 formed on both sides of the ridge 16 in the circumferential direction. Therefore, the bulging in the centrifugal direction is suppressed by the bulging in both sides in the circumferential direction and does not become so large. Further, since a larger compressive force acts on the ridge portion 16 toward the outer peripheral side and the area of the tapered surface 16a of the ridge portion 16 that abuts the facing end surface 22a of the cylinder 22 increases in the centripetal direction, The greater the compressive force acting on the line portion 16, the greater the slip resistance in the centrifugal direction. Therefore, such synergistic action prevents the cylinder 22 from biting into the inner hole 11 of the bumper spring 1.

Further, the bumper spring 1 has the cylinder 22.
No abnormal noise is generated when it comes into contact with the facing end surface 22a of the above.
This is because the contact surface of the cylinder 22 is the taper surface 16a of the protrusion 16 only, and the contact area is small, and the inclined taper surface 16a smoothly contacts with a time lag. As described above, in the bumper spring 1 of the present embodiment, the end portion that opposes and abuts the facing end surface 22a of the cylinder 22 has a ring-shaped flat surface 15 having an outer diameter smaller than the outer diameter of the facing end surface 22a of the cylinder 22. And a plurality of ridges 1 having a tapered surface 16a that projects in the axial direction from the flat surface 15, extends in the radial direction, and is inclined so that the amount of projection in the axial direction increases toward the outer peripheral side.
No. 6 makes it possible to prevent abnormal noise from being generated when the facing end surface 22a of the cylinder 22 comes into contact with the cylinder 22, and to prevent the cylinder 22 from being bitten even under a heavy load.

[Test] In order to confirm the effect of the bumper spring according to the present invention, the state of occurrence of bite in the cylinder of the bumper spring 1 of the above-mentioned embodiment and the bumper springs 5 and 6 of the conventional example 1 and the conventional example 2 was examined. A test to find out was done. In this test, the opposite end face of the cylinder is 20 to 50 m at the end of each bumper spring attached to the tip of the piston rod in the same manner as in the above embodiment.
When each bumper spring is pressed at a pressing speed of m / min in the axial direction between the tip end portion of the piston rod and the opposite end surface of the cylinder, the cylinder bites into the inner hole of the bumper spring. It measures static load.

In each bumper spring used in this test, the end portion of the bumper spring 5 of the conventional example 1 has only a flat surface, and the end portion of the bumper spring 6 of the conventional example 2 has a flat surface and a plurality of hemispherical shapes. The bumper spring 1 according to the embodiment has the same configuration except that the end portion of the bumper spring 1 has a flat surface and a plurality of ridges.

As a result, the load value when the bite of the cylinder occurs is 13 in the case of the bumper spring 5 of the conventional example 1.
00 kg, 1000 kg in the case of the bumper spring 6 of the conventional example 2, and the bumper spring 1 of the example.
In the case of, it was 1300 kg. As a result, it was found that the bumper spring 6 of Conventional Example 2 is likely to bite into the cylinder, whereas the bumper spring 1 of the embodiment is less likely to bite into the cylinder as well as the bumper spring of Conventional Example 1. .

Since this test was carried out by applying a static load, a better result of the bumper spring according to the present invention can be obtained in consideration of the fact that a dynamic load is applied in an actual vehicle. Can be expected.

[0020]

According to the bumper spring of the present invention, the end portion of the bumper spring facing and abutting the facing end surface of the cylinder has a ring-shaped flat surface having an outer diameter smaller than the outer diameter of the facing end surface of the cylinder. It consists of a plurality of ridges that project in the axial direction from a flat surface, extend in the radial direction, and are inclined so that the amount of projection in the axial direction increases toward the outer peripheral side. In this case, no abnormal noise is generated, and it is possible to prevent the cylinder from biting under a heavy load.

[Brief description of drawings]

FIG. 1 is a diagram of a bumper spring according to an embodiment of the present invention.
6 is a cross-sectional view of a portion corresponding to line I-I in FIG.

FIG. 2 is a bottom view of the bumper spring according to the embodiment of the present invention.

3 is a sectional view of a portion of the bumper spring according to Conventional Example 1 corresponding to line IV-IV in FIG.

FIG. 4 is a bottom view of a bumper spring according to Conventional Example 1.

5 is a sectional view of a portion corresponding to VI-VI in FIG. 7 of the bumper spring according to Conventional Example 2. FIG.

FIG. 6 is a bottom view of a bumper spring according to Conventional Example 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bumper spring 11 ... Inner hole 12 ... Upper end part 13 ... Central part 14 ... Lower end part 15 ... Flat surface 16 ... Ridge part 1
6a ... tapered surface 21 ... piston rod 22 ... cylinder 22a ...
Opposite end face

Front page continued (72) Inventor Kazuhito Imaizumi 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (1)

[Claims] 1. A piston rod is coaxially attached to the outer periphery of the piston rod, and is axially compressed between a tip end portion of the piston rod and an opposite end surface of the cylinder to thereby relatively move the piston rod and the cylinder. In the rubber-made cylindrical bumper spring to be regulated, the end of the bumper spring facing and abutting the facing end surface of the cylinder has a ring-shaped flat surface having an outer diameter smaller than the outer diameter of the facing end surface of the cylinder, A bumper spring, comprising: a plurality of projecting ridges that project in the axial direction from the flat surface, extend in the radial direction, and are inclined so that the amount of projection in the axial direction increases toward the outer peripheral side. .