JP2000346206A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit superior sealing performance under a high pressure using conditions by providing a first rubber elastic element fitted in a fitting part in a compacted state relative to one face toward an annular reinforcing ring and a second rubber elastic element having elasticity higher than the first rubber elastic element. SOLUTION: A sealing device 1 which is an oil seal sealing an annular clearance 4 between a shaft hole 2a of a housing 2 and the outer circumferential face 3a of a shaft 3 and provided for preventing leakage of sealed fluid from the seal side M to an atmosphere side O is provided with a fitting part 7 having a first rubber elastic element 6 having an L-shaped-cross-sectional reinforcing ring 5 embedded therein and a seal part 8. A second rubber elastic element 11 having elasticity higher than the first elastic element 6 and a large deformation in receiving a high pressure is provided so as to abut on the end face 6a of the seal side M in the axial direction of the fitting part 7. The second elastic element 11 is held in a region 13 including the internal circumferential face of the axial hole 2a and the end face 6a by an L-shaped-cross-sectional holding member 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device and, more particularly, to a technique for improving the sealing performance of a fitting portion.

[0002]

2. Description of the Related Art Conventionally, in a driving force transmitting portion or the like of a device to which a sealing fluid (hydraulic oil or the like) acts, a sectional configuration explanatory view of FIG. As shown, for example, an inner peripheral surface of a shaft hole 101a of a housing 101 and a shaft 10 inserted through the shaft hole 101a.
2 (rotating shaft) annular gap 103 between outer peripheral surface 102a
And a sealing device 100 (so-called oil seal) is provided to prevent leakage of the sealing fluid from the sealing side M to the atmosphere side O.

[0003] The sealing device 100 has an annular shape, and has an axial portion 105a on the outer peripheral side and a radial portion 105b bent inward from one end of the axial portion 105a (opposite to the sealing fluid 0). It has a U-shaped reinforcement ring 105, a fitting part 106 and a seal part 107 made of a rubber-like elastic body integrally formed so as to employ the periphery of the reinforcement ring 105.

[0004] The seal portion 107 extends from the radial portion 105b of the reinforcing ring 105 to the sealing side M, and the shaft 10 as a sliding surface.
2 main seal portion 107a in contact with outer peripheral surface 102a
And a backup ring 108 made of a resin material that abuts from the side of the main seal portion 107a on the atmosphere side O and maintains the posture. Reference numeral 109 denotes a spring that applies a tension to the main seal portion 107a.

[0005]

SUMMARY OF THE INVENTION A conventional sealing device 100
Then, the adhesion between the fitting portion 106 and the inner peripheral surface of the shaft hole 101a is maintained by the compression of the rubber-like elastic body on the outer periphery of the fitting portion 106 shown in FIG. This adhesion force is substantially proportional to the compression ratio s / h. Here, s is a fitting margin, and h is the thickness of the fitting portion 106.

Accordingly, the adhesion depends on the compressibility of the rubber-like elastic body of the fitting portion 106, and has an upper limit regardless of the environmental conditions (atmospheric pressure on the sealing side M and pressure of the sealing fluid), as shown in FIG. The contact pressure distribution Pv has little change in the axial direction.

Further, the pressure of the sealing fluid is applied to the fitting portion 106.
, The increase Pmax of the contact pressure Pv (distributed in the axial direction) is small, and the adhesion is set sufficiently large with respect to the pressure condition of the sealed fluid in normal use, so that no leakage occurs. However, if the pressure condition of the sealed fluid exceeds a certain value with respect to the adhesion force of the rubber-like elastic body on the outer periphery of the fitting portion 106, oil leakage from the fitting contact portion with the inner peripheral surface of the shaft hole 101a may be concerned.

The compression ratio s / h can be increased by increasing the fitting margin s, that is, the adhesion can be increased to some extent. Therefore, another problem such as a need to increase the rigidity occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a seal at a fitting portion for holding and fixing a sealing device so as to satisfy the conditions of use at high pressure. The purpose is to enhance the nature.

[0010]

In order to achieve the above object, according to the present invention, there is provided a fitting portion fixed to one of two opposite surfaces forming an annular gap, and the fitting portion. A sealing portion that is supported on the other surface and is in contact with the other surface, wherein the sealing portion seals the annular gap, wherein the fitting portion is compressed between the one surface and an annular reinforcing ring. And a second rubber-like elastic body which is higher in elasticity than the first rubber-like elastic body and has a large deformation when subjected to pressure. And

As described above, since the fitting portion is provided with the first and second rubber-like elastic bodies having different elasticities, the sealing device is held by the first rubber-like elastic body, and the second rubber-like elastic body is held. As a result, the fitting portion can exhibit the sealing property, so that the fitting portion can have both stable holding and fixing characteristics and sealing property.

In addition, the second rubber-like elastic body is held between the first rubber-like elastic body and the one surface, and the second rubber-like elastic body is moved by an axial or radial direction under the pressure of a sealing fluid. It is also preferable to provide an annular holding member for pressing the elastic body against the one surface.

By pressing the second rubber-like elastic body against the one surface by the holding member, the contact pressure of the second rubber-like elastic body against one surface can be increased, and the sealing property can be further improved. Can be.

It is also preferable that the second rubber-like elastic body is formed by injecting a liquid into an annular tube having elasticity.

It is preferable that the second rubber-like elastic body is arranged between the one surface and an annular reinforcing ring.

With this configuration, the pressure exerted by the second rubber-like elastic body in the axial direction by the sealing fluid can be applied to the contact surface between one surface and the annular reinforcing ring, and the sealing property can be improved. Can be enhanced.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 is a view for explaining the configuration of a sealing device 1 according to a first embodiment (since it has an axially symmetrical shape, only one side section is shown in accordance with customary practice). The sealing device 1 has a shaft hole 2a (one surface) of the housing 2 as an opposing surface and an outer peripheral surface 3a (the other surface) of the shaft 3.
And an oil seal for sealing the annular gap 4 between the sealing side M and the atmosphere side O to prevent leakage of the sealed fluid.

The sealing device 1 has an annular shape, and has an axial portion 5a on the outer peripheral side and one end of the axial portion 5a (a radial portion 5b which is bent inward from the anti-sealing side (O) and serves as a support portion).
And a fitting portion 7 and a seal portion 8 having a first rubber-like elastic body 6 integrally formed so as to cover the periphery of the reinforcing ring 5. .

The rubber-like elastic body 6 is formed integrally with the seal portion 8 and is fitted into the shaft hole 2a in a compressed state with the reinforcing ring 5 to fix the sealing device to the housing 2. keeping.

The sealing portion 8 is arranged on the sealing side M from the radial portion 5b.
Main seal portion 8a extending to the main seal portion 8a
And a backup ring 9 made of a resin material that abuts from the side of the atmosphere side O and holds the posture.
Reference numeral 10 denotes a spring that applies a tension to the main seal portion 8a.

Further, in this embodiment, when the pressure is higher than the first rubber-like elastic body 6 and pressure is applied so as to abut on the end face 6a of the fitting side 7 on the sealing side M in the axial direction. Annular second rubber-like elastic body 1 having a large deformation amount
1 is arranged.

The second rubber-like elastic body 11 is formed by an annular holding member 12 having an L-shaped cross section.
a is held in a region 13 surrounded by the inner peripheral surface and the end surface portion 6a.

The holding member 12 is provided on the inner peripheral surface 7 of the fitting portion 7.
a, a cylindrical portion 12a capable of sliding connection (loose fitting) with
A flange portion 12b projecting outward from an end of the cylindrical portion 12a on the sealing side M, and is formed of a metal or resin material having a certain degree of rigidity.

In the first embodiment configured as described above, the fitting portion 7 is provided with the first and second rubber-like elastic members 6 and 11 having different elasticities, so that the first rubber-like elastic member is provided. 6, the sealing device 1 can be held, and the second rubber-like elastic body 11 can exert the sealing property of the fitting portion 7, so that the fitting portion 7 has both stable holding and fixing characteristics and sealing performance. Can be provided.

This is because, as shown in FIG. 2A, the holding member 12 is pressurized (FIG.
In response to the arrow p) in (a), the piston 13 is pushed like a piston and moves in the axial direction to reduce the volume of the region 13.

Then, the second compressive force in the region 13
The rubber-like elastic body 11 increases the contact pressure Pv1 on the inner peripheral surface of the shaft hole 2a while being deformed. The contact pressure Pv1 of the second rubber-like elastic body 11 changes according to the pressure of the sealing fluid, and when the pressure is high, the first rubber-like elastic body 6
The contact pressure Pmax is higher than the contact pressure Pv of the contact portion 7, and the sealing performance of the fitting portion 7 can be improved.

As the second rubber-like elastic body 11, any structure can be used as long as it has a higher elasticity than the first rubber-like elastic body 6 and a large amount of deformation when subjected to pressure. be able to.

For example, as shown in FIG. 2 (b), a gel-like pressure receiving member 11b as a liquid is injected into a ring-shaped tube 11a having elasticity of a rubber-like elastic body, so that large deformation and damping occur. It is possible to perform pressure transmission with less pressure, which is preferable.

In addition, a rubbery elastic body having high elasticity such as silicone rubber, a hollow tube, or the like can be used.

The holding member 12 preferably holds the rubber-like elastic body 11 in a compressed state even when the pressure of the sealing fluid is low, in order to prevent the sealing fluid from entering the region 13. .

(Embodiment 2) FIG. 3A is a view for explaining the configuration of a sealing device 21 according to a second embodiment. In the sealing device 21, the same components as those in the sealing device 1 according to the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

The sealing device 21 includes a second rubber-like elastic body 6b constituting the fitting portion 7 and a first rubber-like elastic body 6 disposed between the reinforcing ring 5 and the inner peripheral surface of the shaft hole 2a. Are integrally formed on the sealing side M by so-called two-color molding.

The second rubber-like elastic body 6b is formed of a material having a higher elasticity than the first rubber-like elastic body 6 and having a large deformation when subjected to pressure. In addition, the adhesiveness is higher than that of the first rubber-like elastic body 6.

As described above, in addition to the first rubber-like elastic body 6 for holding and fixing the sealing device 21, the second rubber-like elastic body 6
b, the pressure between the reinforcing ring 5 and the inner peripheral surface of the shaft hole 2a when the pressure of the sealed fluid (arrow p in FIG. 3B) is applied to the second rubber-like elastic body 6b. 2 rubbery elastic body 6b
Is deformed and tries to move in the axial direction (left direction in the figure).

At this time, since the first rubber-like elastic body 6 having high rigidity is continuously present on the atmosphere side O, deformation due to movement is suppressed, and the second rubber-like elastic body 6b and the inner periphery of the shaft hole 2a are formed. The contact pressure Pv2 with the surface increases with the pressure, and the contact pressure Pv2 increases.
max, and stable sealing properties can be obtained even under high pressure conditions.

Further, the configuration of the second embodiment is a simple configuration that does not require a holding member for the rubber-like elastic body 6b.
In addition, the object can be achieved without increasing the size of the sealing device.

[0037]

As described above, according to the sealing device to which the present invention is applied, the sealing performance of the fitting portion for holding and fixing the sealing device is enhanced, and it is possible to use the device under higher pressure conditions.

That is, by providing the first and second rubber-like elastic bodies having different elasticity in the fitting portion, the sealing device is held by the first rubber-like elastic body and fitted by the second rubber-like elastic body. Since it is possible to demonstrate the sealing properties of the joint,
The fitting portion can have both stable holding and fixing characteristics and sealing performance.

By pressing the second rubber-like elastic body against the one surface by the holding member, the contact pressure on the one surface of the second rubber-like elastic body can be increased, and the sealing property can be further improved. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional configuration explanatory view of a sealing device according to a first embodiment.

FIG. 2 is a diagram illustrating a contact surface pressure and a configuration of a second rubber-like elastic body of the sealing device according to the first embodiment.

FIG. 3 is a diagram illustrating a cross-sectional configuration of a sealing device according to a second embodiment and a diagram illustrating a contact surface pressure of the sealing device.

FIG. 4 is a cross-sectional configuration explanatory view of a sealing device according to a conventional technique.

FIG. 5 is a view for explaining fitting of a sealing device according to the related art.

FIG. 6 is a diagram illustrating a contact surface pressure of a sealing device according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing device 2 Housing 2a Shaft hole 3 Shaft 3a Outer peripheral surface 4 Annular gap 5 Reinforcement ring 5a Axial portion 5b Radial portion 6 First rubber-like elastic body 7 Fitting portion 8 Seal portion 8a Main seal portion 9 Backup ring 10 Spring 11 Second rubber-like elastic body 12 Holding member 12a Cylindrical part 12b Flange part 13 Area M Sealed side O Atmospheric side (anti-sealed side)

Claims (4)

[Claims] 1. An annular fitting comprising: a fitting portion fixed to one of two opposing surfaces forming an annular gap; and a seal portion supported by the fitting portion and in contact with the other surface. A sealing device for sealing a gap, wherein the first rubber-like elastic body fitted to the fitting portion in a compressed state between the one surface and an annular reinforcing ring; A second rubber-like elastic body having a higher elasticity than the rubber-like elastic body and having a large deformation when subjected to pressure. 2. A second rubber-like elastic body which holds the second rubber-like elastic body between itself and the one surface, and is displaced in the axial or radial direction by receiving a pressure of a sealing fluid. The sealing device according to claim 1, further comprising an annular holding member that presses an elastic body against the one surface. 3. The sealing device according to claim 1, wherein the second rubber-like elastic body is formed by injecting a liquid into an elastic annular tube. 4. The sealing device according to claim 1, wherein the second rubber-like elastic body is disposed between the one surface and an annular reinforcing ring.