JPH11223235A - Bound bumper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the cracking and improve the durability by constituting a bumper body from a hard rubber, and constituting at least outer surface part of a dust cover from a material resistant to ozone deterioration. SOLUTION: A bumper 1 is formed of a bumper body 7 and a dust cover 6. The body 7 has a thick bellows form having a through-hole 8 for pressing a piston rod 3 in the center part, and it is formed of a hard rubber excellent in durability to compression such as a synthetic material of natural rubber with butadiene rubber, natural rubber or the like. The cover 6 has a cylindrical form continued to the outer edge of the bottom part 9 of the body 7 and concentric to the through-hole 8, and it is formed of a material hardly cracked by ozone deterioration such as ethylene propylene rubber, nitrile rubber and the like. It is further formed into a thin bellows having a contact thickness. The body 7 and the cover 6 are integrally molded by injection molding. Thus, the surface of the cover 6 can be prevented from being cracked by ozone deterioration. Further only the outer surface part of the cover 6 may be formed of a material resistant to ozone deterioration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bound bumper mounted on a vehicle shock absorber.

[0002]

2. Description of the Related Art A dust cover is provided on a shock absorber used for a vehicle suspension or the like to protect a sliding surface of a piston rod protruding from a housing of the shock absorber and a sealing surface between the piston rod and the housing. Is provided.

[0003] As such a dust cover, one generally formed integrally with a bound bumper attached to the tip of a piston rod of a shock absorber is known (for example, see Japanese Utility Model Laid-Open No. 59-123736). ).

The above-mentioned bound bumper has a function of absorbing shock by abutting against an upper end surface of a housing of a shock absorber when a piston rod is largely contracted, and a ride comfort due to a bottom displacement by regulating a maximum displacement amount of the piston rod. And a function to prevent the badness of the system. for that reason,
The above-mentioned bound bumper is made of hard rubber such as natural rubber having excellent durability against compression, and the dust cover integrally formed with this bound bumper is also made of hard rubber.

[0005]

However, the above-mentioned hard rubber has low durability against ozone, and unlike a bound bumper, in a dust cover which constantly repeats expansion and contraction due to micro-vibration, the portion where expansion or distortion occurs may occur. Cracks are easily formed on the surface due to ozone deterioration, and there is a problem in durability.

[0006]

According to the present invention, the bumper body attached to the upper end of the piston rod includes:
In a bound bumper that covers an upper end of a housing that houses the piston rod and that is integrally provided with a dust cover that covers an outer peripheral surface of the piston rod protruding from the upper end, the bumper body is made of hard rubber, and At least the outer surface of the dust cover is made of a material resistant to ozone deterioration. As a result, cracks due to ozone hardly occur on the outer surface of the dust cover, and the durability of the dust cover is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the bound bumper 1 includes a bumper body 7 and a dust cover 6.

The bumper body 7 is formed in a thick bellows shape having a through hole 8 in the center portion into which the piston rod 3 is press-fitted. The bumper body 7 is made of a hard rubber having excellent durability against compression, such as a synthetic material of natural rubber and butadiene rubber, a natural rubber, or a synthetic material of natural rubber and styrene-butadiene rubber.

The dust cover 6 is continuous with the outer edge of the bottom portion 9 of the bumper body 7 and has a cylindrical shape coaxial with the through hole 8, and in a state where the piston rod 3 projects maximum from the housing 4. Also has a predetermined length such that the piston rod 3 and the sealing surface 5 between the piston rod 3 and the housing 4 are not exposed.

The dust cover 6 is made of ethylene propylene rubber, nitrile rubber, acrylic rubber, silicon rubber,
Alternatively, it is made of a material such as fluoro rubber that is less likely to crack due to ozone deterioration, and is formed in a constant thickness and thin bellows shape.

As shown in FIG. 2, the bumper main body 7 and the dust cover 6 of the bound bumper 1 are integrally formed by injection molding. That is, in the mold of the bound bumper 1, the cavity 10 of the bumper body 7 is formed.
For example, a synthetic material of natural rubber and butadiene rubber, which are hard rubbers, is injected from the injection port 11, and, for example, ethylene propylene rubber is injected from the injection port 13 into the cavity 12 of the dust cover 6. The bound bumper 1 is injection molded.

According to the configuration of the above embodiment, the dust cover 6 is made of a material that is resistant to ozone degradation, and the bumper body 7 is made of a material that is excellent in durability against compression. For this reason, in the dust cover 6, it is possible to prevent cracks from being generated on the surface of the dust cover 6 due to ozone deterioration.

Further, the bumper body 7 can absorb an impact at the time of contact with the upper end surface of the housing 4 and can prevent a poor ride comfort due to the bottoming.

In the above embodiment, the entire dust cover 6 is formed of a material resistant to ozone deterioration, but only the outer surface portion of the dust cover 6 exposed to ozone is made of a material resistant to ozone deterioration, The side portions may be formed of the same material as the bumper body 7.

[0016]

According to the first aspect of the present invention, the dust cover is made of a material resistant to ozone deterioration, and the bumper body is made of a hard rubber having excellent durability against compression. In addition to preventing the durability of the dust cover from deteriorating due to ozone deterioration, the bumper body can absorb an impact at the time of contact with the upper end surface of the housing, and can prevent poor riding comfort due to bottoming. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view of a bound bumper according to the present invention.

FIG. 2 is a sectional view of a main part in a mold showing an injection molding method of a bound bumper according to the present invention.

[Explanation of symbols]

 1. Bound bumper 6. Dust cover 7. Bumper body

Claims (1)

[Claims] 1. A dust cover which covers an upper end of a housing for accommodating the piston rod and covers an outer peripheral surface of the piston rod protruding from the upper end is integrally provided on a bumper main body attached to an upper end of the piston rod. In the bound bumper, the bumper main body is made of hard rubber, and at least the outer surface portion of the dust cover is made of a material resistant to ozone deterioration.