JPH0338513Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a gas-filled shock absorber having an outer tube and an inner tube.

[Prior art and its problems]

Conventionally, in a shock absorber 1 as shown in FIG. 1, a seal member 5 having a dust lip 3 and a main lip 4 formed thereon is press-fitted into the inner wall of a housing 2, and a valve body 6 is formed at the tip of the main lip 4 of the seal member 5. By bringing the tip into contact with the upper surface of the rod guide 7, the fluid in the inner tube 8 is made to flow only into the outer tube 9.

However, in the case of such a structure, since the main lip 4 and the valve body 6 are integrated, the movement of the main lip 4 as the rod 10 moves is directly transmitted to the valve body 6, resulting in a one-way valve. The problem was that the functionality of the device deteriorated.

To solve this problem, the shock absorber seal shown in FIG. The body 12 is configured to abut against the end surface of the rod guide 7 and allow the fluid in the inner tube 8 to flow only into the outer tube 9. As a result, the movement of the main lip 4 accompanying the movement of the rod 10 is not directly transmitted to the valve body 12, and the function as a one-way valve can be improved.

However, in order to improve the responsiveness of the valve body 12,
When the wall thickness of the valve body 12 is made thinner and the axial length thereof is increased, the pressure acting on the outer circumference of the valve body 12 causes the valve body 12 to collapse toward the inner circumference, as shown by the broken line in FIG. There is a risk of impairing its functions.

In addition, the violent movement of the rod 10 and the rod 1
The entire shock absorber seal moves in the axial direction due to pressure fluctuations on the outer circumferential side of the main lip 4 caused by the movement of the rod guide 7, and the contact pressure of the valve body 12 in contact with the end face of the rod guide 7 fluctuates, causing variations in valve performance. It had the problem of occurring.

Furthermore, as shown in FIGS. 3 and 3A, a protrusion 7a having a conical outer circumference is provided at the axially outer end of the rod guide 7, and a protrusion 7a is provided on the conical outer circumferential surface of the protrusion 7a. The valve body 6 extending in the axial direction contacts the protrusion 7a, and the leg portion 7b provided on the sealing member 5 and extending in the axial direction contacts the protrusion 7a.
A mode of forming an axial gap between the sealing member 5 and the rod guide 7 is known (Japanese Patent Laid-Open No. 52-124585).
issue).

However, in such a configuration seal member,
When a relative misalignment occurs between the seal member 5 and the rod guide 7 in the axial or radial direction, the contact state between the outer circumference of the protrusion 7a of the rod guide 7 and the valve body 6 changes, resulting in a good condition. This makes it impossible for the valve body to function properly.

Further, when high pressure is applied to the outer circumferential portion of the valve body 6, the problem arises that the valve body 6 collapses toward the inner circumference, as explained in connection with the prior art in FIG. In such a state, the leg portion 7b plays the role of forming an axial gap between the seal member 5 and the rod guide 7, but it is difficult to play the role of preventing the valve body 6 from falling inward. It is. Therefore, in order to prevent the valve body 6 from collapsing toward the inner circumferential surface, it is necessary to make the valve body 6 thick and short. As a result, the responsiveness of the valve body 6 is impaired.

This invention solves the problems of the conventional valves as shown in Figs. 1 to 3A, and provides stable valve function even when high pressure is applied, such as with a shock absorber. The present invention provides a shock absorber seal that exhibits excellent performance.

[Means for solving problems]

In order to achieve the above objectives, this invention
A conventional shock absorber seal as shown in Fig. 2 has an outer circumferential surface on the seal side of the rod guide that is close to the conical inner circumferential surface of the valve body, and an axial end of the seal. A protrusion is provided at the axial end of the rod guide so as to come into contact with the end of the rod guide, and a groove is provided on the outer peripheral surface of the protrusion.

[Effect]

By employing the above-mentioned means, this invention can provide a seal that allows fluid to flow from the inner tube side to the outer tube side, but can reliably prevent fluid flow in the opposite direction.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 4 shows an embodiment of the present invention, in which the shock absorber seal according to the present invention includes an inner pipe 8 filled with oil and an annular space arranged outside the inner pipe 8 in the radial direction. It is used in a two-tube type shock absorber having an outer tube 9 containing an oil liquid in the lower part and gas in the upper part. At one end of this two-tube type shock absorber, there is a rod guide 14.
and housings 15 and 16 adjacent to the outside in the axial direction of the rod guide 14 are fitted, and the rod guide 1
A space 17 is formed between the rod 10 extending from the inside of the shock absorber to the outside by penetrating through the shock absorber 4,
A shock absorber seal 1 is provided in this space 17.
3 is stored.

The rod guide 14 is located between the outer tube 9 and the inner tube 8.
A passage 18 communicating between the space 17 and the passage 17 is formed, and a protrusion 21 having a groove 20 for allowing fluid to flow in the radial direction on the axially outer end face 19 thereof is formed. The shock absorber seal 13 is
A valve body 1 is formed such that an outer circumferential portion 11 is fitted onto an inner circumferential surface of a housing 15, an end portion 22 of the outer circumferential portion 11 is brought into contact with a protrusion 21, and is formed so as to protrude from the end portion 22.
2 is in contact with 19 on the end face of the rod guide.
Therefore, the shock absorber seal 13 is reliably positioned in the axial direction, and the valve body 1
2 functions as a one-way valve that only allows fluid to flow from the inner tube 8 side to the outer tube 9 side.

[Effect of idea]

By adopting the above-described configuration of the present invention, the following effects can be expected.

(1) Even though the valve body 12 is relatively thin and has a shape with good responsiveness, the protrusion 21 is provided, so the valve body 1
Even when high pressure is applied to the outer circumference of the second part, the valve body 12 is supported by the outer circumferential surface of the protrusion 21.
Unlike the prior art shown in the figure, the valve body 12 does not fall inward.

(2) Since the valve body 12 is in elastic contact with the end face of the rod guide, stable valve body function and sealing function can be achieved even if the relative positions of the shock absorber seal 13 and the rod guide 14 in the radial direction are misaligned. It is possible. Also,
The relative axial position of the seal 13 and rod guide 14 is determined in such a way that the axial end of the rod guide 14 comes into contact with the end of the seal, which prevents deterioration in sealing performance due to deviation in the relative axial position. It is something.

(3) Furthermore, since an annular space is usually formed between the outer circumferential surface of the protrusion 21 and the inner circumferential surface of the valve body 12, the pressure of the fluid flowing into the annular space from the groove 20 is
Since it acts uniformly on the inner circumferential surface of the protrusion 21, its responsiveness is good.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a shock absorber using a conventional shock absorber oil seal.
Fig. 2 is a sectional view of another conventional example of a seal for a shock absorber, Fig. 3 is a sectional view of another conventional example of a seal for a shock absorber, Fig. 3A is a partially enlarged view of Fig. 3, and Fig. 4 is a sectional view of another conventional example of a seal for a shock absorber. The figure shows a sectional view of a shock absorber seal that is an embodiment of the present invention. 1...Shock absorber, 2...Housing, 3...Dust lip, 4...Main lip, 5...
... Seal member, 6 ... Valve body, 7 ... Rod guide, 7a ... Protrusion, 7b ... Leg part, 8 ... Inner pipe,
9... Outer pipe, 10... Rod, 11... Outer circumference,
12...Valve body, 13...Shock absorber seal, 14...Rod guide, 15...Housing, 16...Housing, 17...Space, 18...
... Passage, 19 ... End face, 20 ... Groove, 21 ... Protrusion, 22 ... End, 23 ... Inner circumference lip, 24
……Oil seal.

Claims (1)

[Scope of utility model registration request] An inner tube 8 and an outer tube 9 that are combined concentrically with each other to form an annular space, a rod 10 that passes through the inner tube and moves back and forth, a rod guide 14 that is held on the outer tube side and supports the rod, and Housings 15 and 16 are located on the outer side in the axial direction adjacent to the rod guide and are held on the outer tube side, the outer circumferential portion 11 thereof is held on the inner circumferential surface of the housing, and the axial end of the outer circumferential portion on the rod guide side 22 is provided with a valve body 12 having a conical shape that widens at the end, and by bringing the valve body into elastic contact with the end face of the rod guide, fluid flow is allowed from the inner tube side to the outer tube side, but the flow is prevented in the opposite direction. A seal for a shock absorber configured to prevent flow, which has an outer circumferential surface on the seal side of the rod guide that is close to the conical inner circumferential surface of the valve body, and whose axial end portion is close to the outer circumferential surface. A seal for a shock absorber, characterized in that a protrusion 21 is provided so as to come into contact with the end of the part, and a groove 20 is provided that opens on the outer peripheral surface of the protrusion.