JPH0351536Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a shot absorber, and in particular,
This invention relates to an improvement in a shock absorber having an oil seal and a check seal in a bearing member disposed at the upper end of a cylinder.

[Conventional technology]

As a shock absorber having an oil seal and a check seal in a bearing member disposed at the upper end of a cylinder, a proposal as shown in FIG. 3 has been made in the past, for example.

That is, the upper end side of the piston rod 2 whose lower end is inserted into the cylinder 1 projects to the outside so as to pass through the shaft core of a bearing member 3 disposed so as to close the upper end of the cylinder 1. At the same time, an oil seal 4 and a check seal 5 are disposed on the inner circumferential side of the bearing member 3 so as to come into sliding contact with the outer circumference of the piston rod 2.

That is, the oil seal 4
and an oil lip portion 4b, which are disposed on the inner periphery of the upper end of the bearing member 3 so that the dust lip portion 4a is positioned on the upper, outer side, and the oil lip portion 4b is positioned on the lower, inner side. The check seal 5 is disposed on the inner periphery of the intermediate side of the bearing member 3 such that its lip portion 5a is below the oil lip portion 4b. A bush 6 is disposed on the inner periphery of the lower end of the bearing member 3, and the inner periphery of the bush 6 slides on the outer periphery of the piston rod 2.

Therefore, when the piston rod 2 moves up and down with respect to the cylinder 1, the gas mixed with the operation from the expansion side chamber A, which is inside the cylinder 1 below the bearing member 3, flows into the bush 6, the check seal 5, and the piston rod. 2 into the cavity 3a in the bearing member 3, and
The gas mixed with the hydraulic oil flows into the gas chamber D above the external reservoir chamber through the drain port 3b formed in the bearing member 3.

The oil seal 4 is connected to the dust lip portion 4.
A prevents dust from the outside from adhering to the outer periphery of the piston rod 2 and entering the cavity 3a in the bearing member 3, and the oil lip portion 4b prevents the hydraulic oil accumulated in the cavity 3a from leaking to the outside. prevent

[Problem that the invention attempts to solve]

However, the above-mentioned conventional proposal has disadvantages in that the axial length of the bearing member 3 tends to increase, and the durability of the check seal 5 tends to decrease.

That is, in the conventional proposal, since the check seal 5 is disposed below the oil seal 4, the length for disposing the check seal 5 is the minimum required, i.e. Since the length is ensured as an absolutely necessary length, the axial length of the bearing member 3 tends to be increased accordingly.

Also, the check seal 5 has a lip portion 5a.
Since the piston rod 2 is in sliding contact with the piston rod 2, external forces in the contraction and expansion directions are constantly applied to the lip portion 5a each time the piston rod 2 moves up and down, which accelerates wear and deterioration of the lip portion 5a. There is a fear that this will happen. That is, even if the check seal 5 has the reinforcing member 5b, there is a disadvantage that the original function of the lip portion 5a of the check seal 5 is likely to be impaired, making it difficult to obtain long-term durability.

Therefore, in view of the above-mentioned circumstances, the purpose of the present invention is to provide a new shock absorber that prevents the overall length of the shock absorber from increasing and greatly improves the durability of the check seal. do.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the structure of the present invention is such that a bearing member is provided at the upper end of the cylinder, and an oil seal and a check seal are disposed within this bearing member. The oil seal has a shaft portion extending in the radial direction and an oil lip portion that is connected to the inner peripheral side of the shaft portion and makes sliding contact with the piston rod. In a shock absorber that opens and closes a drain port, a retainer member is disposed below the oil seal, and the retainer member is connected to a flange that contacts the lower surface of the shaft of the oil seal and to the inner peripheral side of this flange. The check seal is comprised of a recess into which the oil lip is inserted along the axial direction, the check seal is disposed below the flange of the retainer member, and the lip of the check seal is brought into contact with the outer periphery of the recess so as to be openable and closable. It is characterized by:

〔Example〕

Hereinafter, the present invention will be explained based on the illustrated embodiments.

As shown in FIG. 1, the shock absorber according to a preferred embodiment of the present invention includes a piston portion 11 housed in a cylinder 10, and a piston rod 12 disposed at the lower end of the piston portion 11.
is a bearing member 13 disposed at the upper end of the cylinder 10.
It is formed so that it penetrates through the shaft core and its upper end extends to the outside.

The inside of the cylinder 10 is divided into a growth side chamber A and a compression side chamber B by the piston part 11, and both side chambers A and B are separated by the piston part 11.
The piston portion 11 is configured so that a desired damping force is generated when hydraulic oil passes through the piston portion 11.

In this embodiment, an outer tube 14 is disposed outside the cylinder 10 to form a so-called double-tube type shock absorber, and there is a gap between the cylinder 10 and the outer tube 14. is designated as reservoir chamber C. Although not shown, the reservoir chamber C and the pressure side chamber B are formed so as to communicate with each other via a base valve portion disposed at the lower bottom inside the cylinder 10. Further, above the reservoir chamber C is a gas chamber D.

The upper end, which is the extension side end, of the cylinder 10 is closed by a bearing member 13.
Inside, there is an oil seal 15 and a check seal 1.
6 are included. Further, the bearing member 13 is formed with a drain port 13a that allows communication between the inner circumferential side and the outer circumferential side thereof, and the outer circumferential opening of the drain port 13a is connected to the gas above the reservoir chamber C. It opens into room D. Furthermore, a bush 1 is provided on the inner circumferential side of the bearing member 13.
7 is provided to allow the piston rod 12 to come into sliding contact.

The bearing member 13 is formed so as to be fixed at a predetermined position by bending the upper end of the outer tube 14 inward.

As shown in FIG. 2, the oil seal 15 has a reinforcing member 15b inside its shaft portion 15a, and the upper end of the outer cylinder 14 is bent inward to fix the bearing member 13 in a predetermined position. sometimes,
The shaft portion 15a is arranged so as to be fixed together with the outer cylinder 14 by bending the upper end thereof. The oil seal 15 has a dust lip part 15c and an oil lip part 15d that are connected to each other on the inner circumferential side of the shaft part 15a. They are each positioned on the lower, inner side and are each formed to come into sliding contact with the outside of the piston rod 12.

The dust lip portion 15c is connected to the oil seal 1.
5 Cavity 13b formed in the lower bearing member 13
The oil lip portion 15d prevents dust from entering from the outside, and the oil lip portion 15d prevents gas-containing hydraulic oil from flowing into the cavity 13b from the extension side chamber A through the sliding contact portion between the piston rod 12 and the bush 17. A tightening ring 1 is attached to the outer periphery of the oil lip portion 15d.
5e is interposed.

A retainer member 18 is disposed below the oil seal 15, and the retainer member 18
is a flange portion 18a formed such that its upper surface is in contact with the lower surface of the shaft portion 15a of the oil seal 15;
and a recess 18b formed in a continuous manner on the inner peripheral side of the flange 18a and into which the oil lip 15d can be inserted. An opening 18c is formed at the bottom of the recess 18b, and the piston rod 12 is inserted into the opening 18c.

The retainer member 18 has a protrusion 18d on the lower surface of the flange 18a, and the formation of the protrusion 18 creates a passage 18e that is a gap between the retainer member 18 and other members below. It is something that forms. The passage 18e communicates with a drain port 13a formed in the bearing member 13.

The check seal 16 is positioned below the flange 18a of the retainer member 18 and outside the recess 18b, that is, radially outside the oil lip 15d of the oil seal 15. The check sticker 16 is
It has a lip portion 16a on its inner periphery side, and the lip portion 16a is arranged so as to come into contact with the outer periphery of the recessed portion 18b of the retainer member 18. In the present invention, the check seal 16 does not need to have the reinforcing member 5b as a core material, unlike the check seal 5 of the conventional example.

The check seal 16 allows the gas-containing hydraulic oil that has flowed into the empty chamber 13b from the expansion side chamber A below to pass toward the passage 18e in the retainer 18, but prevents its reverse flow. It is arranged so that it can be obtained.

That is, in the present invention, the piston rod 12
Instead of arranging the check seal 16 below the oil seal 15 in sliding contact with the piston rod 12, the check seal 16 is placed radially outward of the oil seal 15 and in sliding contact with the piston rod 12.
The check seal 16 is disposed without sliding contact with the piston rod 2, whereas the oil seal 4 and check seal 5 in the conventional proposal are disposed directly in the axial direction of the piston rod 2 (see Fig. 3). ), in the case of this invention, oil seal 1
5 and the check seal 16 are arranged parallel to each other in the axial direction of the piston rod 2. And check sticker 1
6 is a concave portion 1 of a retainer member 18 which is immovably disposed such that its lip portion 16a isolates the check seal 16 and the oil seal 15.
8b.

Therefore, the absolute length (third
(see figure) can be omitted.
In addition, the lip portion 16a of the check seal 16 is
This eliminates the need for sliding contact with the piston rod 12 that moves up and down.

In addition, in this embodiment, as shown in FIG. 1, the extension side oil lock mechanism is formed.
The extension side oil lock mechanism is connected to the cylinder 10.
A sleeve 19 disposed on the inner periphery of the upper end, and a floating valve 21 formed to be held with an appropriate gap between the outer periphery of a stopper 20 fixed to the outer periphery of the piston rod 12. The outer periphery of the floating valve 21 comes into sliding contact with the inner periphery of the sleeve 19 at the end of the extension stroke when the piston rod 12 ascends within the cylinder 10. , a desired oil lock chamber is formed on the inner peripheral side of the sleeve 19.

[Effect of idea]

As described above, according to the present invention, the oil lip is inserted into the recess of the retainer member along the axial direction, and the lip of the check seal is brought into contact with the outer periphery of the recess. Since they are arranged outward in parallel, the axial length of the bearing member housing the oil seal and check seal can be greatly reduced, reducing the overall length of the shock absorber. This has the advantage of making it possible to shorten the piston rod and increasing the effective stroke of the piston rod.

Furthermore, according to the present invention, the lip portion of the check seal is in contact with the outer periphery of the recess of the retainer member, and is not subject to repeated expansion and contraction when the piston rod moves up and down, thereby preventing wear and tear on the check seal. This has the advantage that the seal performance is less likely to deteriorate due to deterioration, and the durability of the check seal is greatly improved.

Furthermore, according to the present invention, the durability of the check seal is improved, so there is no need to provide a reinforcing member, and the entire check seal can be made of rubber alone, which has the advantage of contributing to lower costs. be.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing a shock absorber according to a preferred embodiment of the present invention, Fig. 2 is a partial sectional view showing an enlarged view of the main part, and Fig. 3 is a main part of a conventional shock absorber. FIG. 2 is a diagram similar to FIG. 2; 10...Cylinder, 11...Piston part, 12
...Piston rod, 13...Bearing section, 13a...
...Drain port, 13b...Vacancy, 14...Outer cylinder, 15...Oil seal, 15c...Dust lip section, 15d...Oil lip section, 16...Check seal, 16a...Lip section, 18...Retainer Member, 18a... collar part, 18b... recessed part,
18c...opening, 18d...protrusion, 18e...passage, 19...sleeve, 20...stopper, 21
...Idling valve, A...growth side chamber, B...pressure side chamber,
C...Reservoir room, D...Gas chamber.

Claims (1)

[Claims for Utility Model Registration] (1) A bearing member is provided at the upper end of the cylinder, an oil seal and a check seal are provided within this bearing member, and the oil seal is connected to a shaft portion extending in the radial direction and In a shock absorber, an oil lip part is connected to the inner circumference of the oil seal and makes sliding contact with the piston rod, and the lip part of the check seal opens and closes the expansion side chamber of the cylinder and the drain port on the reservoir side. The retainer member includes a flange portion that contacts the lower surface of the shaft portion of the oil seal, and a recess portion that is connected to the inner peripheral side of the flange portion and into which the oil lip portion is inserted along the axial direction. A shock absorber characterized in that the check seal is disposed below the flange of the retainer member, and the lip portion of the check seal is brought into contact with the outer periphery of the recess so as to be openable and closable. (2) A utility model in which the upper end of the check seal is brought into contact with a protrusion on the lower surface of the collar of the retainer member to form a passage, and the passage is connected to a drain port bored in the bearing member. A shock absorber according to claim 1.