JPH0341162Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an improvement of a bump cushion used as an auxiliary spring in a vehicle shock absorber.

(Prior art) Shock absorbers for motorcycles or automobiles are
They are used in conjunction with springs in suspension parts of vehicle bodies to dampen vehicle body vibrations caused by road irregularities, improve wheel contact with the road, and ensure driving stability. As shown in FIG. 4, which is a front view of the main part of the suspension section, a bump cushion 3 is attached to the upper end of the sliding rod 1 of the shock absorber. The bump cushion 3 is made of a highly elastic material such as foamed urethane elastomer and has a cylindrical shape, and is compressed by the outer cylinder 5 of the shock absorber at the time of impact, and is elastically deformed to generate a coil spring. 7, it absorbs the impact energy that cannot be absorbed completely and acts as a kind of auxiliary spring.

Incidentally, in recent years, the proportion of energy that should be absorbed by bump cushions has been increasing from the viewpoint of weight reduction. For this reason, coil springs and the like have been designed so that the bump cushion is compressively deformed by even the slightest unevenness of the road surface, and the energy absorption due to the compressive deformation is added to the energy absorption by the coil spring. As a result, when the bump cushion starts to compress and deform, that is, when the bump cushion starts absorbing energy,
The elastic restoring force of the bump cushion is added to the restoring force of the coil spring alone, so if the initial deformation hardness (spring properties) of the bump cushion is high, the car's springs will suddenly become stiff. Increasingly, this causes passengers to feel as if they have lost their vehicle, resulting in a sense of discomfort in the ride.

In order to reduce this discomfort, conventionally,
The following three measures are being taken. The means is
As in the bump cushion shown in the sectional view of FIG. 3, which lowers the hardness of the entire bump cushion, one end 9 of the shock absorber that contacts the outer cylinder 5 is bent, and the bent portion is made thin. The degree of bending described above is increased.

(Problem to be solved by the invention) However, in this case, there is a problem that the energy absorption by the bump cushion decreases.
In this case, if you try to reduce the thickness of the bent part until the ride comfort is no longer felt, there is a problem that defects such as lack of thickness will occur in that part. The more difficult it becomes to remove the mold during molding, the more difficult it becomes.

The object of this invention is to provide a bump cushion that solves the above problems and improves riding comfort.

(Means for Solving the Problems) In order to solve the above-mentioned problems, this invention provides a notch at the end of the bent portion at one end of the bump cushion.

(Function) When the bump cushion is compressed and deformed, the bent portion at one end is pressed by the outer cylinder of the shock absorber and bent. At this time, the notch provided at the end of the bump cushion reduces the pressure-receiving area of the bending portion, making it easier to bend, resulting in small initial spring characteristics. As a result, the overall spring characteristics do not change drastically due to the start of compressive deformation of the bump cushion, so there is no risk of discomfort in riding comfort.

In the bump cushion, after the bent portion is bent, the portion following the bent portion is also compressed and absorbs impact energy. Therefore, the amount of energy absorbed is determined by the hardness, shape, etc. of the portion following the bent portion, and is hardly affected by the presence of the notch in the bent portion.

(Embodiment) FIG. 1 is a perspective view of an embodiment of a bump cushion according to this invention, and FIG. 2 is a sectional view of the bump cushion taken along line A--A.

This bump cushion 10 is made of a highly elastic material such as foamed urethane elastomer and has a cylindrical shape, one end of which is bent, and a notch 13 is provided at the end of the bent portion 11 to facilitate compression deformation. It has a bellows-like external shape.

The thickness of the bent portion 11 is made thinner than other portions in order to reduce the initial spring characteristics. The thickness is usually preferably 2 to 3 mm, but due to the spring characteristics of the combination with the coil spring,
Or it is determined by the moldability of the bump cushion. If the thickness of the bent portion 11 is made too thin, defects such as insufficient thickness and air pockets are likely to occur during molding of the bump cushion. The degree of bending is determined by taking into consideration the thickness of the bent portion 11, the hardness of the material constituting the bump cushion, and the demoldability during molding.

The number and shape of the notches 13 are optimally selected depending on the thickness and material of the bent portion 11, the desired initial spring characteristics, and the like. Generally, the number of notches is three or more, the bottom part 13a has an arc shape with a radius of 3 mm or more, and the position of the bottom part 13a is set to a curved line 11a.
It is preferable to set the position at least 1 to 2 mm above from the point of initial deterioration of spring characteristics and durability (prevention of tearing at the notch 13, etc.).

This bump cushion 10 has a bent shape portion 11.
It is used by being attached to a shock absorber so that it faces the outer cylinder 5 of the shock absorber shown in FIG.

(Effects of the invention) This invention provides a notch at the end of the bent portion at one end of the bump cushion, which reduces the initial spring characteristics and prevents discomfort from occurring in the ride comfort. It was made. Further, since the initial spring characteristics can be reduced by the notch, there is no need to make the thickness of the bent portion extremely thin, and problems such as underfilling and air pockets do not occur during molding. Furthermore, even if the degree of bending of the bent portion is increased, the presence of the notch has the effect of facilitating demolding during molding. Furthermore, since the hardness of the bump cushion itself is not reduced, there is no risk that the energy absorbability of the entire bump cushion will be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a bump cushion according to an embodiment of this invention, and FIG. 2 is a sectional view taken along line A-A.
Figure 3 is a sectional view of a conventional bump cushion;
The figure is a front view of the main parts of the vehicle body suspension section. 11...bent shape part, 13... notch.

Claims (1)

[Scope of utility model registration request] 1. A bump cushion for a vehicle shock absorber, characterized in that one end of a cylindrical bump cushion made of a highly elastic material is bent, and a notch is provided at the end of the bent portion.