JPH10205625A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve assembly workability with a simple structure by fitting a first sealing member provided with an oil seal lip into a second sealing member provided with a washer having a back-up part and a dust lip. SOLUTION: A first sealing member 2 is provided on an inner circumferential side with an oil seal lip 21 for preventing leakage of a fluid while being brought into contact with a shaft 20, and is provided on an outer peripheral side with a fitting surface part 22 which is fitted to a second sealing member 3. A second sealing member 3 is constituted by baking a resin seal on a washer 31, and is provided with a bend part 31A as a back-up part on an inner circumferential side. The first sealing member 2 is fitted into the second sealing member 3 integratedly with each other so as to cover the atmosphere side of the first member 2. At this time, Since the root 21A of the seal lip 21 which is provided on the first sealing member 2 is supported by the bend part 31A of the washer 31, it is possible to prevent the seal lip 21 from peeling up even if high pressure and the like are generated. It is thus possible to improve assembly workability by only a handling such that the sealing device to be formed integratedly is fitted into an annular clearance.

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, for example, applied to a shaft sealing portion for sealing between members which reciprocate concentrically under high pressure. is there.

[0002]

2. Description of the Related Art Conventionally, this type of sealing device has
For example, there is a sealing device shown in FIG.

[0003] As shown in the figure, the sealing device 100 includes a shaft 2.
This seals an annular gap between the cylinder housing 00 and the cylindrical housing 300 so that fluid such as oil on the sealed fluid side O does not leak to the atmosphere side A.

The sealing device 100 generally includes a first sealing member 110 provided on the sealing fluid side O, a second sealing member 120 provided on the atmosphere side A, and an oil seal constituting the first sealing member 110. And a backup ring 130 for preventing deformation of the lip 112 due to high pressure or the like.

[0005] Then, these first sealing members 110,
Second sealing member 120 and backup ring 130
Are independent members, and are individually assembled when the shaft 200 and the cylindrical housing 300 are assembled.

Hereinafter, each member will be briefly described.

The first sealing member 110 is slidably in contact with the surface of the shaft 200 to prevent a fluid such as oil from leaking from the sealing fluid side O to the atmosphere side A; A resin seal member such as a seal portion 114 that seals the inner periphery of the housing 300 in close contact therewith is baked on the washer 111.

Then, the first sealing member 110 is
And when assembling to the cylindrical housing 300,
The seal portion 114 is fitted on the inner periphery of the housing 300, and the first sealing member 110 is substantially fixed. In addition, a spring 113 is provided on the outer peripheral side of the oil seal lip 112, so that the oil seal lip 112 is securely brought into contact with the surface of the shaft 200 by the spring force of the spring 113.

In order to prevent the oil seal lip 112 from being deformed due to high pressure or the like and the sealing function being impaired, a backup ring 130 is attached to the root of the oil seal lip 112. The mounting of the backup ring 130 is performed by connecting the first sealing member 110 to the shaft 2.
This is performed before assembly to the housing 300 and the cylindrical housing 300.

[0010] By mounting the backup ring 130, the oil seal lip 11
2 does not turn over to the atmosphere side A and can always be properly sealed.

A second sealing member 120 is slidably in contact with the surface of the shaft 200 to prevent dust such as dust and dirt from entering the sealing fluid side O from the atmosphere side A. Also, a resin sealing member such as a sealing portion 123 that is tightly sealed to the inner periphery of the housing 300 is baked on the washer 121.

Then, the second sealing member 120 is connected to the shaft 200.
And when assembling to the cylindrical housing 300,
The seal portion 123 is fitted on the inner periphery of the housing 300, and the second sealing member 120 is substantially fixed.

With such a configuration, an annular gap between the shaft 200 and the cylindrical housing 300 is sealed.

[0014]

However, in the case of the prior art as described above, a washer is required for each of the first sealing member 110 and the second sealing member 120, and the first sealing member 110 and the second sealing member 120 are also required. The number of components has increased, such as the necessity of a backup ring 130 for preventing deformation of the oil seal lip 112 provided on the member 110.

Further, since the first sealing member 110, the second sealing member 120, and the backup ring 130 must be individually assembled, the number of assembling steps is increased, and the assembling workability is poor.

Further, since the sealing device is constituted by combining the individual parts independently as described above, the device tends to be large-sized (particularly in the axial direction), and the demand for the miniaturization of the device is increasing. It was difficult to answer.

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 sealing device which has a simple structure, improves assembly workability, and has excellent reliability. It is in.

[0018]

According to the present invention, there is provided a sealing device for sealing an annular gap between a shaft and a cylindrical member, which is mounted concentrically and relatively movable relative to each other. A first sealing member having an oil seal lip slidably in contact with said shaft;
A washer provided with a backup portion for supporting the root of an oil seal lip provided on the sealing member, an outer peripheral seal portion that contacts and seals the cylindrical member, and a dust lip that slidably contacts the shaft. And a second sealing member fitted to the first sealing member.

Therefore, the first sealing member does not require a washer due to the washer provided on the second sealing member due to the fitting of the first sealing member and the second sealing member, and the washer is provided in the backup portion. , The number of parts is reduced, and
It is only necessary to assemble the sealing device in which the first sealing member and the second sealing member are fitted and integrated into the annular gap between the shaft and the cylindrical member, so that the assembling workability is improved. Further, since the base of the oil seal lip is supported by the backup portion of the washer, the oil seal lip always seals properly, so that the reliability is excellent.

The backup unit provided in the washer includes:
It is preferable that the first sealing member has a curved portion curved along a root of an oil seal lip provided on the first sealing member.

Therefore, since the washer has the curved portion, the root of the oil seal lip is supported by the curved portion.

It is preferable that a frictional force reducing means for reducing a frictional force at a contact portion between the washer and the first sealing member is provided.

Therefore, since the sliding can be performed at the contact portion between the washer and the first sealing member, the eccentricity of the sealing device is improved when the shaft and the cylindrical member are eccentric.

The second sealing member may be provided with a regulating portion for regulating the eccentricity of the shaft.

Therefore, the eccentricity of the shaft is regulated by the regulating portion.

It is preferable to provide a frictional force reducing means for reducing the frictional force on the surface of the regulating portion on the shaft side.

Therefore, since the surface of the regulating portion and the shaft can slide, respectively, when the shaft and the cylindrical member are eccentric, the eccentricity followability of the sealing device is improved.

The frictional force reducing means is preferably made of polytetrafluoroethylene coated on the surface of the member.

Therefore, by coating with polytetrafluoroethylene, the friction coefficient of the surface is reduced, and the frictional force is reduced.

[0030]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(Embodiment) FIGS. 1, 2 and 3 show a sealing device according to an embodiment of the present invention. FIG. 1 is a schematic sectional view showing a state where the sealing device is assembled, FIG. 2 is a schematic sectional view showing a first sealing member constituting the sealing device, and FIG. 3 is a second sectional view constituting a sealing device. It is a schematic structure sectional drawing of a sealing member.

As shown in the drawing, the sealing device 1 seals an annular gap between the shaft 20 and a housing 30 which is a cylindrical member, and a fluid such as oil on the sealed fluid side O is supplied to the atmosphere side A.
This is to prevent leakage.

The sealing device 1 generally includes a first sealing member 2 provided on the sealing fluid side O and a second sealing member 2 provided on the atmosphere side A.
And is integrally formed by fitting with the sealing member 3.

First, the first sealing member 2 will be described with reference to FIG.

The first sealing member 2 has an oil seal lip 21 on the inner peripheral side to slidably contact the shaft 20 to prevent leakage of fluid such as oil, and the second sealing member on the outer peripheral side. 3
Is provided with a fitting surface portion 22 that fits into the fitting portion.

Further, a spring 23 for securely bringing the oil seal lip 21 into contact with the shaft 20 is provided.

Next, the second sealing member 3 will be described with reference to FIG.

The second sealing member 3 has a structure in which a resin seal is baked on a washer 31. The washer 31 has a bent portion 31A functioning as a backup portion on the inner peripheral side. The portion 31A has a curved shape that follows the root shape of the oil seal lip 21 described above.

A dust lip 32 slidably in contact with the shaft 20 on the inner peripheral side to prevent the entry of dust such as dust, and a guide 33 as a regulating portion for regulating the eccentricity of the shaft 20.
And

Further, an outer peripheral lip 34, which is an outer peripheral seal portion that slidably contacts the housing 30, is provided on the outer peripheral side, and an outer peripheral dust lip 35 is provided.

In this embodiment, the lip structure in which the outer peripheral side is slidably contacted to improve the eccentricity followability has been described. A configuration for improving the pressure resistance may be adopted as the configuration for making the sealing contact.

The first sealing member 2 and the second sealing member 3 having the above-described structure are combined with the second sealing member 2 so that the atmosphere side A of the first sealing member 2 is covered as shown in FIG. Sealing member 3
And the first sealing member 2 is fitted to the sealing device 1 to form the sealing device 1 integrally.

At this time, since the root 21A of the oil seal lip 21 provided on the first sealing member 2 is supported by the bent portion 31A of the washer 31, the oil seal lip 21 is turned up even if a high pressure is generated. Without this, the oil seal lip 21 can always function properly.

Further, with such a configuration, only one washer is required and the backup ring is not required as a separate part, so that the number of parts can be reduced.

Further, since the integrated sealing device 1 only needs to be fitted into the annular gap between the shaft 20 and the housing 30, the workability in assembling is improved.

The contact portion between the washer 31 and the first sealing member 2 or the surface portion of the guide 33 (see FIG.
By applying friction reducing means (for example, by coating polytetrafluoroethylene (PTFE)) to each part, slipping between the members is improved, and when the shaft 20 and the housing 30 are eccentric, a sealing device is provided. The eccentricity followability of 1 can also be improved.

(Other Embodiments) FIGS. 4, 5 and 6 show other embodiments of the present invention. In the present embodiment, various aspects of the configuration such as the shape of the guide 33 are shown. Other configurations and operations are the same as those of the first embodiment, so that the same components are denoted by the same reference numerals and description thereof will be omitted.

FIG. 4 shows a configuration in which a notch 33A is provided in the guide 33 in order to reduce the frictional force between the guide 33 and the shaft 20.

With such a configuration, sliding resistance is reduced, the movement of the shaft 20 becomes smoother, and the followability of the sealing device 1 is further improved.

FIG. 5 shows that the guide 33 has a parallel projection 33 in the circumferential direction in order to reduce the frictional force between the guide 33 and the shaft 20.
B shows the configuration provided.

With such a configuration, similarly, the sliding resistance is reduced, the movement of the shaft 20 becomes smoother, and the followability of the sealing device 1 is further improved.

FIG. 6 shows that the guide 3 is in the normal state.
3 is set so as to have a gap G between the shaft 20 and
The configuration in which the guide 33 and the shaft 20 come into contact with each other due to the eccentricity of the shaft 20 is shown.

With such a structure, the shaft 2
When 0 is not eccentric, there is no sliding resistance due to the guide 33, the sliding resistance is further reduced, the movement of the shaft 20 becomes smoother, and the followability of the sealing device 1 is further improved.

The configurations shown in FIGS. 4, 5, and 6 can be appropriately combined with each other.

[0055]

According to the present invention, the first sealing member does not require a washer due to the washer provided on the second sealing member by fitting the first sealing member and the second sealing member. Also,
Since the washer has the backup portion, the number of components can be reduced, and the configuration can be simplified and the device can be downsized.

In addition, the sealing device in which the first sealing member and the second sealing member are fitted and integrated into one body only needs to be assembled into the annular gap between the shaft and the cylindrical member, so that the assembly workability is improved. Is improved.

Further, since the root of the oil seal lip is supported by the backup portion of the washer, the oil seal lip always seals properly, so that the reliability is excellent.

The backup unit provided in the washer is provided in the first
By supporting the root of the oil seal lip with a curved portion that curves along the root of the oil seal lip provided on the sealing member, it is possible to prevent the oil seal lip from being turned up by pressure or the like.

If the frictional force reducing means for reducing the frictional force at the contact portion between the washer and the first sealing member is provided, the contact portion between the washer and the first sealing member becomes slippery at each, and the shaft and the cylinder When the member is eccentric, the eccentricity followability of the sealing device is improved.

If the second sealing member is provided with a regulating portion for regulating the eccentricity of the shaft, the eccentricity of the shaft can be regulated.

If the frictional force reducing means for reducing the frictional force is provided on the surface of the regulating portion on the shaft side, the respective members become slippery.
When the shaft and the cylindrical member are eccentric, the eccentricity followability of the sealing device is improved.

The frictional force reducing means can reduce the frictional force by coating the surface of the member with polytetrafluoroethylene to reduce the frictional coefficient of the surface.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a state where a sealing device according to an embodiment of the present invention is assembled.

FIG. 2 is a schematic sectional view of a first sealing member constituting the sealing device according to the embodiment of the present invention.

FIG. 3 is a schematic sectional view of a second sealing member constituting the sealing device according to the embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing an example of a form of a guide of a second sealing member constituting a sealing device according to another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing an example of a form of a guide of a second sealing member constituting a sealing device according to another embodiment of the present invention.

FIG. 6 is a schematic configuration diagram showing an example of a form of a guide of a second sealing member constituting a sealing device according to another embodiment of the present invention.

FIG. 7 is a schematic configuration sectional view showing a state where a sealing device according to a conventional technique is assembled.

[Explanation of symbols]

 Reference Signs List 1 sealing device 2 first sealing member 21 oil seal lip 21A root (of oil seal lip 21) 3 second sealing member 31 washer 31A bent part (backup part) 32 dust lip 33 guide 34 outer lip 35 outer dust lip 20 Shaft 30 Housing

Claims (6)

[Claims] 1. A sealing device for sealing an annular gap between a shaft and a cylindrical member, which is assembled so as to be concentrically movable relative to each other, comprising an oil seal lip slidably contacting the shaft. A sealing member, a washer provided with a backup portion for supporting a root of a lip provided on the first sealing member, an outer peripheral sealing portion for sealing by contacting the cylindrical member, and slidably on the shaft. And a second sealing member having a dust lip in contact with the first sealing member, the second sealing member being fitted with the first sealing member. 2. A backup unit provided in the washer,
The sealing device according to claim 1, further comprising a curved portion that curves along a root of an oil seal lip provided in the first sealing member. 3. The sealing device according to claim 1, further comprising a frictional force reducing unit configured to reduce a frictional force at a contact portion between the washer and the first sealing member. 4. The sealing device according to claim 1, wherein the second sealing member is provided with a regulating portion for regulating eccentricity of the shaft. 5. The sealing device according to claim 1, wherein a frictional force reducing means for reducing a frictional force is provided on a surface of the regulating portion on the shaft side. 6. The sealing device according to claim 3, wherein the frictional force reducing means is polytetrafluoroethylene coated on the surface of the member.