JP2003074710A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device of high reliability, capable of adjusting friction without impairing sealing performance. SOLUTION: A sliding part of a seal lip 3 is provided with a roughened region S in a partial region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device used for a shaft sealing portion of various devices.

[0002]

2. Description of the Related Art Conventionally, as a sealing device of this type,
For example, it is used as a so-called rear cushion oil seal for two-wheeled vehicles or as a gas stay oil seal for four-wheeled vehicles that seals high-pressure gas in a portion where a shaft reciprocates at a relatively high pressure.

A conventional sealing device will be described below with reference to FIGS. 5 and 6.

FIG. 5 is a schematic view showing a state in which the sealing device is applied, and FIG. 6 is a schematic sectional view of a conventional sealing device.

As shown in FIG. 5, the sealing device 100 according to the prior art is reciprocally disposed in an annular gap between a shaft 400 and a cylinder housing 500 concentrically provided on the shaft 400. The purpose of the present invention is to seal high-pressure gas, which is the sealing target fluid, and to prevent fluid such as gas or oil from leaking from the sealing target side O to the atmosphere side A in the figure.

The sealing device 100 prevents the leak of the sealing fluid by sealing the inner circumference of the cylinder housing 500 and the outer circumference of the shaft 400.
The configuration of the seal lip that is in sliding contact with the outer periphery of 00 plays an important role in the sealing performance. As the configuration of this seal lip, there were about three types as shown in FIG. .

The sealing device 100 shown in FIG. 6 (a) has the most basic structure, and the seal lip 101 is a so-called female cut plane lip or mold lip, which is formed by cutting or by molding. It is what is formed.

The seal lip 101 is formed of an elastic member and slides on the shaft 400 to seal it while following the eccentricity of the shaft 400.

Further, the sealing device 200 shown in FIG.
The seal lip 201 of the above has the configuration shown in FIG.
Further, an annular protrusion (parallel or cut protrusion) 202 is formed on the surface of the lip on the atmosphere side A, which is intended to improve the oil retaining ability on the surface.

Further, the sealing device 300 shown in FIG.
The seal lip 301 has the configuration shown in FIG.
Further, a concave portion (or an annular groove or the like) 302 is formed on the surface of the lip on the atmosphere side A, and like the annular projection 202 of the sealing device 200, the oil retaining ability on the surface is improved.

[0011]

However, in the case of the above-mentioned prior art, the following problems have occurred.

In the above-described sealing device, when moving relative to the shaft, the seal lip is deformed by frictional resistance received from the shaft surface and slides on the shaft surface for sealing.

When the sealing device moves to the atmosphere side A relative to the shaft (actually, the shaft moves to the sealing target side O while the sealing device is stationary), the seal lip moves to the sealing target side O. It will be in a state of being deformed to be stretched by being pulled by

At this time, the seal lip is in a state in which the peripheral surface portion extending from the substantially edge portion of the tip thereof to the atmosphere side is in planar contact with the shaft surface.

Then, the seal lip is pressed against the shaft by the pressure from the side O to be sealed, the amount of deformation of the seal lip increases, the contact area with the shaft increases, and the sliding between the seal lip and the shaft. Lubricating oil is pushed out from the part.

As a result, the friction becomes high, and it is easy to induce problems such as accelerated wear.

In the structure shown in FIG. 6B, a closed space is formed by a plurality of annular projections, and oil can be retained between the annular projections, but the projections scratch the oil film on the shaft surface. In such a case, the friction becomes high.

Further, in the structure shown in FIG. 6 (c), oil can be retained in the recesses or the annular grooves, but the peripheral surface on which the recesses or the annular grooves are formed is a smooth surface, so When the surface is pressed against the shaft, the lubricating oil is extruded from the sliding portion between the smooth surface and the shaft, and even in such a case, the friction is increased.

In order to solve these problems, a method of controlling the oil film by adjusting the contact angle of the seal lip with the shaft has been conventionally used. By this method, it is possible to reduce the friction, but in this case, since a large amount of oil is sent by adjusting the angle of the lip, the hermeticity is deteriorated.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is to provide a highly reliable sealing device capable of adjusting friction without impairing the sealing property. Especially.

[0021]

In order to achieve the above-mentioned object, in the present invention, the two moving substantially concentrically with each other.
A sealing device for sealing an annular gap between members, comprising:
In a sealing device including a seal lip having a sliding portion that makes sliding contact with one of the members, the sliding portion includes a roughened region in a partial region. Characterize.

On the peripheral surface of the seal lip on the side opposite to the sealing target side with respect to the lip tip, a roughening process is performed on a region on the side opposite the sealing target side from the lip tip and including at least the sliding portion. It is also preferable that the above is applied.

It is also preferable that the predetermined width and the size of the roughening process in the roughened region are set according to the pressure from the side to be sealed.

With this structure, the region not roughened comes into close contact with one member, so that the sealing performance can be secured, and in the region roughened. Since it is possible to hold the lubricant, it is possible to improve the lubricity.

Then, by adjusting the size of the roughening process in the roughened region, the holding force of the lubricant in the valley part can be obtained in the valley part and the peak part formed by the roughening process. It is possible to adjust the balance with the contact state of the mountain portion with one member.

Therefore, by adjusting the predetermined width from the lip tip and the size of the roughening process in the roughened region according to the pressure from the side to be sealed,
Friction can be adjusted without impairing the hermeticity.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
The material, the shape, and the relative arrangement of them should be appropriately changed depending on the configuration of the device to which the invention is applied and various conditions, and the scope of the invention is not limited to the following embodiments.

A sealing device according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic configuration diagram of a sealing device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing a mounted state of the sealing device according to the embodiment of the present invention, and FIG. It is a principal part enlarged view of the sealing device which concerns on embodiment of this invention.

The sealing device according to the embodiment of the present invention can be used for sealing various fluids by being used as a shaft sealing portion of various devices, for example, a so-called two-wheeled vehicle for sealing high pressure gas. It is suitable to be used as a rear cushion oil seal or a gas stay oil seal for a four-wheeled vehicle at a portion where the shaft reciprocates at a relatively high pressure.

As shown in FIG. 1, the sealing device 1 according to the present embodiment has an annular gap between a shaft 20 as one member and a cylinder housing 30 concentrically provided on the shaft 20. It is reciprocally arranged so as to seal a high-pressure gas that is a sealing fluid.
To prevent the fluid such as gas or oil from leaking from the side to the atmosphere side A which is the side opposite to the hermetically sealed side.

The sealing device 1 according to this embodiment is roughly
The sealing device 1 is a so-called U packing having a substantially U-shaped cross section, which is composed of an outer peripheral lip 2 and a seal lip 3.

Then, the sealing device 1 configured as described above
Is mounted in an annular gap between the shaft 20 and the cylinder housing 30, so that the outer peripheral lip 2 seals the inner periphery of the cylinder housing 30, and the seal lip 3 seals the shaft 20.
By sealing the outer circumference of, the side between the sealing target side O and the atmosphere side A is sealed.

Next, the seal lip, which is a feature of this embodiment, will be described.

The seal lip 3 of the present embodiment has the structure shown in FIG.
As shown in FIG. 6, in the peripheral surface extending from the lip tip toward the atmosphere side A, in the area S excluding the area T having a predetermined width t (width in the axial direction from the lip tip to the atmosphere side A) from the lip tip. , Roughened. The seal lip 3 constitutes a sliding portion that slides on the shaft 20 by the regions T and S.

Here, the region T is not roughened and constitutes a sliding surface which comes into close contact with the shaft 20 and exhibits sealing performance, and is constituted by a smooth surface.

Further, the area on the atmosphere side A of the roughened area S is at least an area constituting the sliding portion of the seal lip 3 which is in sliding contact with the shaft 20. That is, even if the sliding portion is not configured in the initial mounting state, roughening is performed in a range where the sliding portion can be formed due to deformation or wear due to relative movement with the shaft.

FIG. 3 is an enlarged view for explaining the roughened region S.

As shown in FIG. 3, the region S of the seal lip 3 is roughened so that the valleys 4 and the peaks 5 are formed.
And are formed.

As a result, only the ridges 5 are in contact with the shaft 20, and the valleys 4 hold a lubricant such as oil or grease. Since the mountain portion 5 is formed by roughening, the contact area with the shaft 20 is small, and the contact state with the shaft 20 can be adjusted by the size of roughening.

With the above configuration, the sealing device 1 is
Since the region T of the seal lip 3 is in close contact with the shaft 20, the sealing performance can be ensured.

In the region S of the seal lip 3, since the roughening process is performed, it is possible to hold a lubricant such as oil or grease in the valley portion 4, and the roughening process is performed. Since the formed ridges 5 are in contact with the shaft 20, it is possible to improve the lubricity for the shaft 20 and reduce the sliding torque.

That is, in the sealing device 1, the regions T and S constituting the sliding portion of the seal lip 3 with respect to the shaft 20 are adjusted (the length of the predetermined width t from the lip tip to the atmosphere side A is adjusted. Area T which is a smooth surface
And the size (ratio of the contact area with respect to the shaft 20) with the region S to which the roughening process is applied), the pressure from the sealing target side O under the environment to which the sealing device 1 is applied. Accordingly, the friction can be adjusted without impairing the hermeticity.

Further, by adjusting the size of the roughening process in the region S, the holding force of the lubricant in the valley part 4 in the valley part 4 and the peak part 5 formed by the roughening process,
It is possible to adjust the balance between the mountain portion 5 and the contact state with the shaft 20, and it is possible to optimally adjust the friction.

In the sealing device 300 shown in FIG. 6 (c) in the section of the prior art, although the lubricant is held in the recess 302, the region in which the recess 302 is formed is a smooth surface. This smooth surface was in close contact with the shaft to increase the friction, but in the present embodiment, the peak portion 5 formed by roughening is brought into contact with the shaft 20 and the peak portion 5 is The contact area with the oil film or the shaft 20 can be adjusted by the balance with the valley portion 4 that holds the lubricant (size of roughening).

Here, in the sealing device 1, the width t of the region T and the size Rz of roughening (ten-point average roughness) are: t = 0.3 to 2.0 mm Rz = 2 to 50 , The material of the sealing device 1, the pressure of the fluid to be sealed, the type of fluid to be sealed, the type of lubricant (grease, etc.), etc.
It is preferable to set it appropriately according to the tightening margin set by these.

As described above, according to the present embodiment, it is possible to provide a highly reliable sealing device capable of adjusting friction without impairing the sealing property. For example, a rear cushion, a gas stay or By being suitably applied to a shock absorber or the like, it becomes possible to improve the operability of these mechanisms.

In the present embodiment, the region S except the region T having the predetermined width t is roughened from the tip of the lip, but the present invention is not limited to this, and one portion of the sliding portion of the seal lip 3 is used. It is sufficient that the partial region is roughened.

In the above description, the so-called U-packing has been described as the sealing device 1. However, the present invention is not limited to this, and sliding contact is made with either one of the two members that move relatively concentrically relative to each other. It suffices that a seal lip having a sliding portion is provided, and it can be suitably applied to the sealing device 10 as shown in FIG. 4, for example.

A sealing device 10 according to another embodiment will be described below with reference to FIG. FIG. 4 is a schematic configuration diagram of a sealing device according to another embodiment. Since the sealing device 10 is similar to the above-described sealing device 1 in its function and the like, description thereof will be omitted.

As shown in FIG. 4, the sealing device 10 is a seal composed of a reinforcing ring 15 having a substantially L-shaped cross section and a rubber-like elastic body integrally formed so as to cover the periphery of the reinforcing ring 15. And a section 14.

The reinforcing ring 15 is composed of an axial portion 15a on the outer peripheral side and a radial portion 15b bent from the one end on the atmosphere side A of the axial portion 15a to the inner diameter side.

The seal portion 14 is formed so as to extend from the fitting portion 12 fitted in the cylinder housing 30 and the radial direction portion 15b of the reinforcing ring 15 to the sealing target side O, and is in sliding contact with the shaft 20. And a seal lip 13 that does.

Similar to the seal lip 3 described above, the seal lip 13 is also provided with the roughened region S in the sliding portion with respect to the shaft, and the above-described effect can be obtained.

[0055]

As described above, according to the present invention, since the region not subjected to the roughening process closely contacts one member,
The sealing performance can be ensured, and the lubricant can be retained in the roughened region, so that the lubricity can be improved.

Then, by adjusting the size of the roughening process in the roughened region, the holding force of the lubricant in the valley part can be obtained in the valley part and the peak part formed by the roughening process. It is possible to adjust the balance with the contact state of the mountain portion with one member.

Therefore, by adjusting the predetermined width from the lip tip and the size of the roughening process in the roughened region according to the pressure from the side to be sealed,
Friction can be adjusted without impairing the hermeticity.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a sealing device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a mounted state of the sealing device according to the embodiment of the present invention.

FIG. 3 is an enlarged view of a main part of the sealing device according to the embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a sealing device according to another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a mounted state of a sealing device according to a conventional technique.

FIG. 6 is a schematic configuration diagram of a sealing device according to a conventional technique.

[Explanation of symbols]

1 Sealing device 2 outer lip 3 seal lip 4 Tanibe 5 Yamabe 10 Sealing device 12 Fitting part 13 seal lip 14 Seal part 15 Reinforcement ring 15a axial part 15b radial part 20 axes 30 cylinder housing S roughened area T Smooth surface (area not roughened) O Side to be sealed A atmosphere side

Claims (3)

[Claims] 1. A sealing device for sealing an annular gap between two members that move substantially concentrically relative to each other, and has a sliding portion that is in sliding contact with one of the two members. A sealing device including a seal lip, wherein the sliding portion includes a roughened region in a partial region. 2. On the peripheral surface of the seal lip on the side opposite to the sealing target side with respect to the lip tip, the rough surface is provided in a region including at least the sliding portion on a side opposite to the sealing target side from a predetermined width from the lip tip. The sealing device according to claim 1, wherein the sealing device is processed. 3. The predetermined width and the size of the roughening process in the roughened region are set according to the pressure from the side to be sealed. The sealing device according to 2.