JPH11257409A - Hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent positional dislocation of an assembled part obstructing smooth assembly from generating at assembling a hydraulic shock absorber. SOLUTION: On the way of a piston rod extending outward from a shock absorber main body, a flange part 3t gradually spreading the diameter toward the shock absorber main body 2 side, and after reaching the maximum diameter, returning to the original diameter through a step part is formed, the piston rod 3 is partitioned into an invasion part 3a and a mount part 3m defining the flange part 3t to be the boundary, and a stopper rubber 10 is fitted to the position contacted with the flange part 3t in the invasion part 3s. In this case, the invasion part 3s and the mount part 3m are separated members from each other, and the flange part 3t can be formed on either end part of the invasion part 3s or the mount part 3m.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber constituting, for example, a vehicle suspension mechanism.

[0002]

2. Description of the Related Art Conventionally, a type shown in FIG. 3 is known as a hydraulic shock absorber used for a suspension mechanism of a vehicle. The hydraulic shock absorber 51 has a shock absorber main body 52 whose inner oil chamber is vertically defined by a piston and whose lower end is attached to a wheel, and which protrudes from the upper end side of the shock absorber main body 52 and whose tip end is attached to the vehicle body side. Piston rod 53
The piston rod 53 has a tapered portion t
53m of large diameter penetration part and 53m of small diameter mounting part via
The mount 53m is connected to the vehicle body. Then, the invading portion 53 near the tapered portion t
A stopper rubber 54 is fitted to s, a periphery of the stopper rubber 54 is covered with a dust cover 55, and a cover plate 56 is fitted around the tapered portion t.

In such a hydraulic shock absorber 51, a damping force is generated by sliding of a piston in an oil chamber of a shock absorber main body 52 in accordance with advance and retreat of a piston rod 53, and a damper effect is obtained. When the piston rod 53 contracts, the stopper rubber 54 is brought into contact with the bump stopper cap 57 at the end of the shock absorber main body 52 to absorb the impact at the end of the stroke.

[0004]

By the way, in assembling such a hydraulic shock absorber 51, a piston integrated with a piston rod 53 is inserted into a shock absorber main body 52, and a piston insertion opening of this shock absorber main body 52 is inserted. After covering with the bump stopper cap 57, the stopper rubber 54 is fitted to the large-diameter entry portion 53s of the piston rod 53, and then the cover plate 56 and the dust cover 55 are assembled. When the fitting position is returned in the pushing direction due to the elasticity of the stopper rubber 54 when the fitting is performed from the side of the portion 53m, for example, as shown in FIG. There is a problem in that it is difficult to assemble due to interference when trying to fit it. Also, the piston rod 53
If the diameter of the intruding portion 53s and the diameter of the mounting portion 53m are made equal to each other, the mounting position of the cover plate 56 becomes unclear, and means for separately fixing the stopper rubber 54 and the like to a predetermined position is required. This increases the number of parts and the number of assembling steps.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cap member mounted on one end side of a shock absorber main body, and a cap member penetrating through a rod insertion hole from the inside of the shock absorber main body to the outside. In a hydraulic shock absorber provided with a piston rod extending to the outside and a stopper rubber fitted to a predetermined portion of the external extension of the piston rod, in the vicinity of the fitting portion of the stopper rubber, toward the shock absorber main body side After the diameter gradually increases, the diameter is sharply reduced and a maximum diameter is formed as a flange portion smaller than the diameter of the rod insertion hole of the cap member. The intrusion portion and the mount portion on the extension end side are partitioned so that the stopper rubber is fitted on the intrusion portion side of the piston rod and at a position in contact with the flange portion.

To assemble such a hydraulic shock absorber, a piston integrated with a piston rod is inserted from one end side of the shock absorber main body, and the cap member is connected to the shock absorber through a rod insertion hole of the cap member from the distal end of the piston rod. Move to the piston insertion opening of the main body and fix it so as to cover the piston insertion hole. Next, by inserting the stopper rubber from the distal end side of the piston rod, pushing it toward the shock absorber main body, and moving it to a position beyond the flange, the stopper rubber can always be fitted at a predetermined position. The subsequent assembly of the components can be easily performed. For this reason, the fitting hole of the stopper rubber is made smaller than the maximum diameter of the flange portion, and is set to a diameter that can abut the step portion of the flange portion when fitted to a predetermined position. In addition, since the diameter of the flange gradually widens toward the shock absorber main body side, the stopper rubber can be moved smoothly when it is moved to the back of the flange.

[0007] It is preferable that the penetration portion of the piston rod and the mount portion have the same diameter. If the diameter of the intruding portion of the piston rod and the diameter of the mounting portion are made the same, no trouble is required when, for example, the intruding portion and the mounting portion are integrally formed, and the intruding portion and the mounting portion are manufactured separately. Even when the same material can be used, it is convenient.

Further, the intruding portion of the piston rod and the mounting portion are formed of separate members, and a flange portion is formed at one end of the member on one of the intruding portion and the mounting portion. The members may be joined. In this case, the production of the flange portion is facilitated. In particular, if the flange portion is formed on the mount portion side, the shaping becomes further simple because the shaft diameter becomes wider toward the distal end side.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall view of a hydraulic shock absorber, in which a piston rod is fully extended, and FIG. 2 is an enlarged view of a main part of FIG. As shown in FIG. 1, a hydraulic shock absorber 1 according to the present invention includes a shock absorber main body 2 and a piston rod 3 extending from one end of the shock absorber main body 2. , And the upper end of the piston rod 3 can be connected to the vehicle body.

The shock absorber main body 2 includes a cylinder 5 built in a bottom tube 4 and a piston 6 slidable in the cylinder 5, and a space in the cylinder 5 is moved upward by the piston 6. The upper chamber is partitioned into a chamber a (the upper chamber has a very small volume because the shock absorber is fully extended in the figure) and a lower chamber b, and the upper chamber a and the lower chamber b are filled with oil. ing.

The space between the cylinder 5 and the bottom tube 4 is formed as a reservoir chamber c. The reservoir chamber c is filled with oil and gas, and the oil in the reservoir chamber c and the oil in the cylinder 5 are transferred to the bottom. The connection is made via a valve 7.

A bump stopper cap 8 as a cap member is mounted on the upper end side of the shock absorber main body 2.
This bump stopper cap 8 has a piston rod 3
Is provided with a rod insertion hole 8h through which the rod is inserted.

A lower end of the piston rod 3 is connected to a piston 6, and a flange portion 3t is formed at a predetermined position in the middle of extending to the outside through the bump stopper cap 8. The flange portion 3t has a diameter that expands in a tapered shape toward the shock absorber main body 2 side (the lower side in the figure), and finally narrows rapidly through the step portion to return to the original diameter. Has a smaller diameter than the rod insertion hole 8h of the bump stopper cap 8, and with the flange 3t as a boundary,
The shock absorber main body 2 side is the intrusion portion 3s, and the opposite side is the mount portion 3m. The diameter of the intrusion portion 3s and the diameter of the mount portion 3m are the same, and the mount portion 3m is connected to the vehicle body.

The intruding portion 3s of the piston rod 3 has
As shown also in FIG. 2, the stopper rubber 10 is fitted, and is in contact with the step of the flange 3t. The diameter of the fitting hole of the stopper rubber 10 is slightly smaller than the maximum diameter of the flange 3t. A cover plate 11 having a fitting hole having substantially the same shape as the outer shape of the flange 3t is fitted over the stopper rubber 10 and around the flange 3t,
A dust cover 12 is attached around the cover plate 11 so as to cover the periphery of the stopper rubber 10 and the entrance 3s.

A joint collar 13 is fitted to the mount 3m of the piston rod 3, and a mount rubber 14 is mounted around the joint collar 13 to reduce an impact applied to a joint on the vehicle body side. I have.

The hydraulic shock absorber 1 as described above absorbs the shock transmitted from the road surface to the vehicle body during running of the vehicle by the movement of oil and the compression of gas when the piston 6 slides.
At the stroke terminal in the contraction direction of the stopper rubber 10
Abuts on the bump stop cap 8 to absorb the impact. The method of assembling the hydraulic shock absorber 1 is performed in the following procedure.

First, the piston 6 integrated with the piston rod 3 is inserted into the cylinder 5 of the shock absorber main body 2. Then, the rod insertion hole 8h of the bump stopper cap 8 is inserted from the tip of the piston rod 3 and moved to the end of the shock absorber main body 2, and the bump stopper cap 8 is moved to the shock absorber main body 2.
To join.

Next, the stopper rubber 10 is fitted from the end of the piston rod 3 and is pushed inward. At the time of passing through the flange 3t, the fitting hole of the stopper rubber 10 expands by elasticity, and the fitting hole of the stopper rubber 10 that has expanded when passing through the location of the maximum diameter contracts with a sense of moderation. It is fitted to the invading portion 3s while being in contact with the step portion.

Next, when the cover plate 11 having the fitting hole of the same shape as the flange 3t is fitted, the stopper rubber 10 does not protrude around the flange 3t and interfere therewith. Can be. Thereafter, the joint collar 13 and the mount rubber 14 are attached.

The intruding portion 3s of the piston rod 3 and the mounting portion 3m may be constituted by different members. In this case, the flange 3t is connected to the end of the intruding portion 3s or the mount 3
It is provided at one of the m-side end portions, and the two are joined by welding or the like via, for example, a flange portion 3t. In particular, if the flange portion 3t is provided at the end portion on the mount portion 3m side, the shaft diameter is simply increased. Since it becomes a form spreading toward the side, it can be easily molded.

When the intruding portion 3s and the mounting portion 3m are integrally formed, if the flange 3t is also integrally formed, the number of parts does not increase and the assembling procedure becomes easy, but the flange 3t is formed separately. It may be configured so as to be fitted and fixed at a predetermined location.

[0022]

According to the present invention as described above,
In the middle of the piston rod extending from the shock absorber main body to the outside, a flange portion whose diameter gradually increases toward the shock absorber main body, then sharply decreases and the maximum diameter is smaller than the diameter of the rod insertion hole of the cap member. The piston rod is partitioned into the entry portion and the mount portion with the flange portion as a boundary, and the stopper rubber is fitted on the entry portion side and at a position in contact with the flange portion. It can be fitted to the position and can be easily assembled.

If the intruding portion of the piston rod and the mounting portion are made to have the same diameter, for example, when the intruding portion and the mounting portion are integrally formed, no trouble is required, and the intruding portion and the mounting portion are manufactured separately. Even when the same material can be used, it is convenient. Furthermore, if the invading portion and the mounting portion are formed of different members, and the flange portion is formed at one end of the member on either side of the invading portion and the mounting portion, the forming of the flange portion can be performed easily.

[Brief description of the drawings]

FIG. 1 is an overall view of a hydraulic shock absorber with a piston rod fully extended.

FIG. 2 is an enlarged view of a main part of FIG. 1;

FIG. 3 is a main part view of a conventional hydraulic shock absorber;

FIG. 4 is an explanatory diagram illustrating a failure state of a conventional assembly.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hydraulic shock absorber, 2 ... Shock absorber main body, 3 ... Piston rod, 3m ... Mount part, 3s ... Penetration part, 3t ... Flange part, 8
... Bump stopper cap, 8h ... Rod insertion hole, 10
... stopper rubber.

Claims (3)

[Claims] A cap member attached to one end of the shock absorber main body; a piston rod extending from the inside of the shock absorber main body to the outside through a rod insertion hole of the cap member;
A hydraulic shock absorber having a stopper rubber fitted to a predetermined portion of the outer extension of the piston rod, wherein the diameter gradually increases toward the shock absorber main body near the fitting portion of the stopper rubber. After that, a flange portion is sharply reduced in diameter and a maximum diameter is formed to be smaller than the diameter of the rod insertion hole of the cap member, and the piston rod is extended from the entrance portion on the shock absorber main body side with the flange portion as a boundary. A hydraulic shock absorber, wherein the stopper rubber is partitioned into an end-side mount portion, and the stopper rubber is fitted at a position where the stopper rubber comes into contact with the flange portion on the intruding portion side of the piston rod. 2. The hydraulic shock absorber according to claim 1, wherein
A hydraulic shock absorber characterized in that a penetration portion of the piston rod and a mount portion have the same diameter. 3. The hydraulic shock absorber according to claim 1, wherein the intruding portion of the piston rod and the mounting portion are formed of different members, and an end of a member on either one of the intruding portion and the mounting portion. A hydraulic shock absorber, wherein the flange portion is formed in a portion, and both members are joined at the position of the flange portion.