JP2000081071A - Dust cover for hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate blow molding and prevent the falling from a shock absorber by constituting a dust cover of a thermoplastic elastomer, and integrally providing a reinforcing ring erected upward in the internal circumferential edge of its small diameter opening. SOLUTION: This dust cover 10 is manufactured by blow molding using thermoplastic elastomer as a material, the whole shape is approximately cylindrical, an opening 11 having a smaller diameter than the outer diameter of a cover cap is formed in its upper end, and a reinforcing ring 12 is integrally provided upward along the internal circumferential edge. A bent part 13 and a reinforcing recess 14 followed by the shape of the cover cap are formed in the lower part of the opening 11, a stage part 15 locked with the bottom end of the cover cap is formed thereunder, and an annular reinforcing projection 16 is formed in the bottom end. The use of the thermoplastic elastomer can facilitate the blow molding and reduce the cost and the reinforcing ring is integrally provided so as to prevent the falling from the shock absorber even in using the thermoplastic elastomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dust cover mounted on a hydraulic shock absorber.

[0002]

2. Description of the Related Art If fine dust enters between a piston rod and a rod guide or the like, it may damage the piston rod or enter the inside of a hydraulic shock absorber. Therefore, as disclosed in Japanese Utility Model Laid-Open No. 55-147550, a dust cover is conventionally attached so as to cover the insertion portion of the piston rod into the damper tube.

[0003] Since the dust cover does not constitute a strength member, it is required to be lightweight, non-corrosive and inexpensive, and is often made of synthetic resin as described in the above publication. Then, in order to prevent the dust cover from falling off after being mounted on the hydraulic shock absorber, a part of the dust cover is heated and deformed after being mounted so as to be locked on a cap or the like.

[0004]

However, the resin material constituting the conventional dust cover is inferior in heat resistance and may be deformed when placed near a heat source. For a resin product having a cylindrical shape or a bag shape, blow molding is advantageous. It is conceivable that the dust cover is manufactured by blow molding to form a cylindrical shape. A thermoplastic elastomer is excellent as a material for blow molding.

[0005] However, a dust cover made of a thermoplastic elastomer cannot be fixed to a cap by being partially deformed by heating after molding. In addition, because it is rich in elasticity, in the same shape as the conventional synthetic resin dust cover,
If some force acts, it may come off.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a dust cover of a hydraulic shock absorber is formed of a thermoplastic elastomer, and the dust cover is formed on an inner peripheral edge of the small-diameter opening upward. An upright reinforcing ring portion is provided integrally. The use of a thermoplastic elastomer as a material facilitates blow molding, and the provision of a reinforcing ring can effectively prevent falling off from the hydraulic shock absorber.

[0007] In particular, by providing a neck portion in an intermediate body made by blow molding, and cutting the neck portion so as to leave at least a portion of the neck portion in a main body (a portion serving as a dust cover), no special process is required. , A reinforcing ring portion can be provided.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is an overall view of a hydraulic shock absorber equipped with a dust cover according to the present invention, FIG. 2 is an enlarged sectional view of the dust cover according to the present invention, and FIG. 3 is a sectional view taken along line AA of FIG.

In the hydraulic shock absorber, an inner tube 2 is disposed in an outer tube 1 and these outer tubes 1
An oil reservoir S1 is formed between the inner tube 2 and the inner tube 2. A piston rod 5 is inserted into the inner tube 2 via a rod guide 3 and a seal 4.
A piston 6 is fixed to the lower end of the cylinder, and the interior of the inner tube 2 is defined by the piston 6 into an upper oil chamber S2 and a lower oil chamber S3.
Is communicated through.

A cover cap 9 is provided between the upper end of the piston rod 5 and the joint 8, and the upper end of the dust cover 10 according to the present invention is externally inserted into the cover cap 9.

The dust cover 10 is manufactured by blow molding using a thermoplastic elastomer, has a substantially cylindrical shape as a whole, and has an opening 11 having a diameter smaller than the outer diameter of the cover cap 9 at the upper end. A reinforcing ring portion 12 is integrally provided upward along the inner peripheral edge of the opening 11.

A curved portion 13 following the shape of the cover cap 9 and a concave portion 14 for reinforcement are formed below the small-diameter opening portion 11, and a cover cap 9 is formed below the curved portion 13 and the concave portion 14. A stepped portion 15 is formed at the lower end portion, and an annular reinforcing convex portion 16 is formed at the lower end portion.

Next, the dust cover 1 will be described with reference to FIGS.
0 will be described. FIG. 4 shows a cutting device, in which a cutter 21 is attached to a lever 20 and a driving pulley 22 and a driven pulley 2 are provided at both ends of the lever.
3 and a belt 24 is stretched between the driving pulley 22 and the driven pulley 23.

The intermediate 3 obtained by blow molding
In order to manufacture the dust cover 10 from scratch, the intermediate body 30 is inserted into the ring 25 and held by the bearings 31, and the belt 24 of the cutting device is pressed against the intermediate body 30 in this state, and the belt 24 is caused to run. This causes the intermediate 30 to rotate. Then, the cutting device is further strongly pushed in the direction of the arrow in FIG. 4 to cut and remove the bag portions 30a at both ends of the intermediate body 30 rotated by the cutter 21 in FIG.

By the way, as shown in FIG. 5, a neck portion 30b is formed near one bag portion 30a of the intermediate body 30, and at least a part of the neck portion 30b is removed when the one bag portion 30a is removed. By cutting so as to remain on the main body side (a part to be a dust cover), the remaining part becomes the reinforcing ring portion 12.

[0016]

According to the present invention as described above,
By using a thermoplastic elastomer as a material for the dust cover of the hydraulic shock absorber, blow molding is facilitated and cost can be reduced. In addition, a reinforcing ring that stands upward is provided integrally with the inner peripheral edge of the small-diameter opening at the upper end of the dust cover, effectively preventing falling off from the hydraulic shock absorber even when a thermoplastic elastomer is used as the material. it can.

Further, a neck portion is provided on the intermediate body formed by blow molding, and at least a part of the neck portion is cut so as to remain in the main body (a portion serving as a dust cover), so that a special process is not performed. , A reinforcing ring portion can be provided.

[Brief description of the drawings]

FIG. 1 is an overall view of a hydraulic shock absorber equipped with a dust cover according to the present invention.

FIG. 2 is an enlarged sectional view of a dust cover according to the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a schematic diagram of a cutting device.

FIG. 5 is a diagram showing a state where an intermediate of a dust cover is being cut by a cutting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer tube, 2 ... Inner tube, 3 ... Rod guide, 4 ... Seal, 5 ... Piston rod, 6 ... Piston, 7 ... Bottom valve, 8 ... Joint, 9 ... Cover cap, 10 ... Dust cover, 11 ... Small diameter Opening 12; reinforcing ring 13; curved portion 14;
15 Step, 16 Reinforcement convex, 20 Lever, 21
Cutter, 22: drive pulley, 23: driven pulley, 24
... belt, 25 ... ring, 30 ... intermediate body, 30a ... bag part, 30b ... neck part, 31 ... bearing, S1 ... oil reservoir, S2 ... upper oil chamber, S3 ... lower oil chamber.

Continuation of front page (72) Inventor Yasunobu Takagi 2-32-7 Omori Nishi, Ota-ku, Tokyo F-term product F-term (reference) 3J069 AA50 CC29 CC30

Claims (2)

[Claims] 1. A dust cover of a hydraulic shock absorber having a cylindrical shape and an upper end portion having a small-diameter opening portion, and the small-diameter opening portion is externally attached to a cap and fixed thereto, wherein the dust cover is made of a thermoplastic elastomer. A dust cover for a hydraulic shock absorber, wherein a reinforcing ring portion rising upward is integrally provided on an inner peripheral edge of the small diameter opening of the dust cover. 2. The dust cover according to claim 1, wherein the dust cover is obtained by molding an intermediate by blow molding, and cutting and removing a bag portion from the intermediate.
A dust cover for a hydraulic shock absorber, wherein a neck portion is provided in the intermediate body, and the neck portion is used as a reinforcing ring portion by leaving the neck portion on the main body side during the cutting.