JP2003106462A - Oil seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil seal 1 capable of improving an assembling workability of a shaft 5 and so forth and suppressing the peeling of an adhesive, when there is an adhesive part 13 between rubber and a metal in the oil seal 1 in the pressureproof oil seal 1 having a structure backing up the seal lip 6 by a backup ring 8. SOLUTION: This oil seal 1 is provided with the seal lip 6 slidably and closely contacted with the circumferential surface 5a of a counter-member such as the shaft 5 and so forth, a backup ring holder part 7 in the back of the seal lip 6, and the backup ring 8 disposed in the backup ring holder part 7. The backup ring holder part 7 is provided with an elastic projection 11 facing to the backup ring 8 and the elastic projection 11 pushes the backup ring 8 toward the counter-member such as the shaft 5 and so forth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal, which is a type of sealing device, and more particularly to a pressure resistant oil seal having a structure for backing up a seal lip using a backup ring.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a seal lip 53 slidably in contact with a peripheral surface 52a of a mating member such as a shaft 52 is provided, and the seal lip 53 is provided behind the seal lip 53 (upper and lower sides in the drawing).
There is known an oil seal 51 for pressure or high pressure conditions in which a backup ring holder portion 54 for holding a backup ring 55 is provided, and a backup ring 55 for backing up the seal lip 53 is provided in the backup ring holder portion 54.

However, in this conventional technique,
As shown in the figure, the inner diameter of the backup ring 55 is φA.
Is formed to be larger than the outer diameter dimension φB of the shaft 52, and thus a relatively large radial gap c is formed between the backup ring 55 and the shaft 52. Therefore, the oil seal 51 is formed in the radial gap c. When a part of the rubber of (the part on the back side of the seal lip 53, which is the so-called heel portion 53a) is sandwiched by the pressure deformation, heel protrusion occurs, and when the seal lip 53 slides on the shaft 52 in this state. Peeling or gouging wear occurs on the seal lip 53,
The sealability may be impaired.

To solve this problem, as shown in FIG. 7, the inner diameter dimension φA of the backup ring 55 is reduced and formed to be substantially the same as the outer diameter dimension φB of the shaft 52. It is conceivable to prevent the radial gap c from being formed with the shaft 52.

However, in this case, as shown in FIG. 8, there is no escape area on the outer peripheral side of the backup ring 55 when the backup ring 55 is expanded by the shaft 52 when the shaft 52 is inserted. 55 is difficult to spread, and therefore, the workability of assembling the shaft 52 is not so good. Further, as shown in FIG. 9, the backup ring 55 is radially displaced due to the eccentricity of the shaft 52 after the shaft 52 is inserted. When pressed by,
A relatively large load acts on the rubber-to-metal adhesive portion 56 of the oil seal 51, which may cause adhesive peeling.

[0006]

In view of the above points, the present invention can improve the workability of assembling a shaft or the like in an oil seal having a structure for backing up a seal lip using a backup ring. Moreover, it is an object of the present invention to provide an oil seal capable of suppressing the occurrence of peeling of the adhesive when the oil seal has a bonded portion of rubber and metal.

[0007]

In order to achieve the above object, an oil seal according to claim 1 of the present invention has a seal lip slidably in close contact with the peripheral surface of a mating member such as a shaft. In an oil seal in which a backup ring holder part is provided behind the lip and a backup ring is arranged in the backup ring holder part, an elastic protrusion is provided in the backup ring holder part toward the backup ring. is there.

An oil seal according to a second aspect of the present invention has a seal lip slidably in contact with a peripheral surface of a mating member such as a shaft, and a backup ring holder portion is provided behind the seal lip. In an oil seal having a backup ring arranged in the backup ring holder part, an elastic projection is provided on the backup ring holder part toward the backup ring, and the elastic projection presses the backup ring against a mating member such as the shaft. It is a feature.

Like the oil seal according to claim 1 of the present invention having the above structure, when the backup ring holder portion is provided with the elastic projection toward the backup ring, the backup ring is spread by the shaft when the shaft is inserted. Even if the backup ring is crushed, the escape ring can be secured by crushing the elastic protrusion. Further, after the shaft or the like is inserted, even if the backup ring is pressed in the radial direction due to the eccentricity of the shaft or the like, the backup ring can absorb the load by crushing the elastic protrusions.

A second aspect of the present invention having the above structure.
Also in the oil seal by the above, since the backup ring holder part has the elastic projection facing the backup ring, even if the backup ring is expanded by the shaft when inserting the shaft, the backup ring should crush the elastic projection. This makes it possible to secure an escape area. Further, after the shaft or the like is inserted, even if the backup ring is pressed in the radial direction due to the eccentricity of the shaft or the like, the backup ring can absorb the load by crushing the elastic protrusions. In addition, in the oil seal according to the second aspect, since the backup ring is pressed against the shaft or the like by the elastic protrusion provided on the backup ring holder portion, the radial gap is formed between the backup ring and the shaft or the like. Since it is not formed, it is possible to effectively suppress the occurrence of the above-mentioned heel protrusion.

The present technical proposal includes the following technical matters.

In other words, in order to achieve the above object, one oil seal proposed by the present application has a projection on the backup ring holder portion, and the backup ring is constantly pressed against the shaft to minimize the gap between the shaft and the backup ring. This prevents the rubber from entering the gap between the backup ring and the shaft. Further, the backup ring can be expanded to the outside by using a protrusion as a mechanism for pressing the backup ring onto the shaft. Therefore, it is possible to maintain the ease of assembling the seal and avoid the adverse effects of the shaft eccentricity.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross section (cut end surface) of an oil seal 1 according to an embodiment of the present invention.

In the oil seal 1 according to this embodiment, the seal lip 6 which is the constituent element of the oil seal 1 is attached to the backup ring 8.
An oil seal for pressure-resistant or high-pressure condition having a structure for backing up by means of the following structure.

That is, first, the rubber 4 is attached to the metal mounting ring 3.
The oil seal main body 2 is provided by vulcanizing and adhering to the oil seal main body 2.
A seal lip 6 that slidably and closely adheres to the oil seal 1 and the shaft 5, and a backup ring 8
A backup holder portion 7 that holds the oil seal 1 and an outer peripheral seal portion 9 that seals between the oil seal 1 and a housing (not shown) in which the oil seal 1 is mounted are integrally formed. A garter spring 10 for adjusting contact pressure is fitted on the seal lip 6.

The backup ring holder portion 7 provided on the axial rear side of the seal lip 6 (upper and lower sides in the drawing) is
The rubber 4 and the mounting ring 3 are formed into an annular groove shape that opens inward in the radial direction, and a backup ring 8 that backs up the seal lip 6 is fitted to the groove-shaped holder portion 7. There is. Further, an elastic projection 11 is integrally formed on the inner surface of the holder portion 7 toward the inner side in the radial direction, and a backup ring 8 is arranged on the inner peripheral side of the elastic projection 11 and the elastic projection 11 is formed. Due to its elasticity, the backup ring 8 is slidably pressed against the peripheral surface 5a of the shaft 5. An annular space 12 is formed between the inner surface of the holder portion 7 and the backup ring 8.

As shown in FIG. 2, a plurality of protrusions 11 are formed equidistantly on the circumference at predetermined intervals, but they may be formed in an annular shape. The cross-sectional shape of the protrusion 11 is not particularly limited.

The backup ring 8 is made of a material such as resin having a hardness higher than that of the rubber 4 of the oil seal body 2, and has an inner diameter φA in its initial state.
Is formed to have substantially the same size as the outer diameter dimension φB of the shaft 5.
Further, as shown in FIG. 3, the backup ring 8 has a bias cut 8 formed by obliquely cutting one place on the circumference.
a is provided, so that it is possible to increase the diameter dimension by transforming the initial state of FIG. 3 (A) as shown in FIG. 3 (B), and the initial state of FIG. 3 (A). Therefore, it is possible to reduce the diameter dimension by deforming as shown in FIG.

In the oil seal 1 having the above structure, the elastic projection 11 is provided on the inner surface of the backup ring holder portion 7 of the oil seal body 2 inward in the radial direction, and the backup ring 8 is provided on the inner diameter side of the elastic projection 11. Are arranged, as shown in FIG.
When the backup ring 8 is pushed apart by the shaft 5 when the shaft 5 is inserted, the backup ring 8 is elastically protruded.
It is possible to escape outward in the radial direction by temporarily crushing. Therefore, since the escape area of the backup ring 8 is secured when the shaft 5 is inserted in this way, the workability of the assembly when the shaft 5 is inserted can be improved.

Further, as shown in FIG. 5, after inserting the shaft 5,
When the backup ring 8 is pushed in the radial direction by the eccentricity of the shaft 5, the backup ring 8 can temporarily crush the elastic protrusions 11 to absorb the load due to the eccentricity of the shaft 5. Therefore, by absorbing the load in this way, it is possible to prevent the load from acting on the adhesive portion 13 between the rubber 4 and the mounting ring 3 in the oil seal body 2, and thus to prevent the adhesive peeling. Can be suppressed.

Further, since the backup ring 8 is pressed against the peripheral surface 5a of the shaft 5 by the elastic projection 11, according to this structure, a radial gap is formed between the backup ring 8 and the shaft 5 as in the prior art. Never formed. Therefore, it is possible to suppress the occurrence of heel protrusion in which the heel portion 6a of the seal lip 6 is sandwiched in the radial gap, and thus it is possible to prevent the seal lip 6 from being peeled or gouged.

When the backup ring 8 is cut as described above, since the elastic projection 11 is provided, the adhesion of the cut portion is kept good and the eccentricity followability and the adhesion of the shaft 5 are maintained. Can be improved.

The effect of preventing the heel from protruding is that the backup ring 8 is attached to the shaft 5 by the elastic projection 11.
Not only when it is pressed against the peripheral surface 5a, but also when the elastic projection 11 functions as a kind of spacer and the contact pressure of the backup ring 8 with respect to the shaft 5 is set to zero. Therefore, axis 5
However, the backup ring 8 may be configured so as to contact the shaft 5 with the contact pressure just zero, instead of being pressed against the shaft 5 by the elastic protrusions 11 in a state where it is not yet eccentric.

[0025]

The present invention has the following effects.

That is, first, in the oil seal according to claim 1 of the present invention having the above structure, since the backup ring holder portion is provided with the elastic projection toward the backup ring, the shaft is inserted when the shaft or the like is inserted. When the backup ring is spread out by, for example, the backup ring can escape in the radial direction by crushing the elastic protrusion. Therefore, since the backup ring can escape when the shaft or the like is inserted, the workability of assembling when the shaft or the like is inserted can be improved.

When the backup ring is pushed in the radial direction by the eccentricity of the shaft or the like after insertion of the shaft or the like, the backup ring can absorb the load due to the eccentricity of the shaft or the like by crushing the elastic protrusions. Therefore, since it is possible to absorb the load in this way, it is possible to prevent the load from acting on the adhesive portion when the oil seal has the adhesive portion between the rubber and the metal, and therefore the adhesive peels off. It can be suppressed from occurring.

A second aspect of the present invention having the above structure.
Also in the oil seal by the above, since the backup ring holder part is provided with the elastic projection toward the backup ring, when the backup ring is expanded by the shaft etc. when inserting the shaft etc., the backup ring crushes the elastic projection. As a result, it is possible to escape in the radial direction. Therefore, since the backup ring can escape when the shaft or the like is inserted, the workability of assembling when the shaft or the like is inserted can be improved.

When the backup ring is pushed in the radial direction by the eccentricity of the shaft or the like after insertion of the shaft or the like, the backup ring can absorb the load due to the eccentricity of the shaft or the like by crushing the elastic protrusion. Therefore, since it is possible to absorb the load in this way, it is possible to prevent the load from acting on the adhesive portion when the oil seal has the adhesive portion between the rubber and the metal, and therefore the adhesive peels off. It can be suppressed from occurring.

Further, since the backup ring is pressed against the peripheral surface of the shaft or the like by the elastic protrusions provided on the backup ring holder portion, a radial gap is formed between the backup ring and the shaft or the like as in the prior art. Never be done. Therefore, it is possible to suppress the occurrence of heel protrusion in which the heel portion of the seal lip is sandwiched in the radial gap, and thereby to prevent peeling and gouging wear of the seal lip.

[Brief description of drawings]

FIG. 1 is a half-cut end view of an oil seal according to an embodiment of the present invention.

FIG. 2 is a partial sectional view of an oil seal body in the oil seal.

3A is a partial cross-sectional view showing an initial state of a backup ring in the oil seal, FIG. 3B is a partial cross-sectional view showing a radially expanded deformation state of the backup ring, and FIG.
Is a partial cross-sectional view of the backup ring showing the reduced diameter deformation state

FIG. 4 is a half-cut end view showing a state where the oil seal is inserted into a shaft.

FIG. 5 is a half-cut end view showing a state of the oil seal when the shaft is eccentric.

FIG. 6 is a half-cut end view of an oil seal according to a conventional example.

FIG. 7 is a half-cut end view of an oil seal according to a comparative example.

FIG. 8 is a half-cut end view showing a state where the oil seal is inserted into a shaft.

FIG. 9 is a half-cut end view showing a state of the oil seal when the shaft is eccentric.

[Explanation of symbols]

1 oil seal 2 Oil seal body 3 mounting ring 4 rubber 5 axes 5a circumference 6 seal lip 6a heel part 7 Backup ring holder 8 backup ring 8a Bias cut 9 Outer peripheral seal 10 Garter spring 11 Elastic protrusion 12 voids 13 Adhesive part

Claims (2)

[Claims] 1. A backup ring holder part (7) has a seal lip (6) slidably in close contact with a peripheral surface (5a) of a mating member such as a shaft (5), and behind the seal lip (6). ) Is provided, and in the oil seal (1) in which the backup ring (8) is arranged on the backup ring holder part (7), an elastic protrusion (11) is provided on the backup ring holder part (7) toward the backup ring (8). ) Is provided, the oil seal. 2. A backup ring holder part (7) has a seal lip (6) slidably in contact with a peripheral surface (5a) of a mating member such as a shaft (5), and behind the seal lip (6). ) Is provided, and in the oil seal (1) in which the backup ring (8) is arranged on the backup ring holder part (7), an elastic protrusion (11) is provided on the backup ring holder part (7) toward the backup ring (8). ) Is provided, and the backup ring (8) is pressed against a mating member such as the shaft (5) by the elastic protrusion (11).