JPH0571541U - Sealing device - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the eccentricity tracking capability of the backup ring. [Structure] An elastic backup ring support portion 10 having an elastic force for urging in a radial direction is provided in a holder 7 of a seal lip 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sealing device used for, for example, a power steering rod of an automobile, and more particularly to a sealing device having a backup ring.

[0002]

[Prior Art]

 A conventional sealing device of this type is, for example, one shown in FIG. That is, in this sealing device 100, the lip tip 103 of the annular seal lip 102 formed integrally with the reinforcing ring 101 is brought into sealing contact with the outer peripheral surface of the movable shaft 105 by the spring 104, and the sealing target fluid side O It is configured so that the fluid does not leak to the atmosphere side A. A backup ring 107 is attached to the holder 106 formed by the inner peripheral surface of the seal lip 102 and the reinforcing ring 101, and when the pressure from the fluid O to be sealed is generated, the sealing property caused by the deformation of the seal lip 102. It is possible to prevent the deterioration of

[0003]

[Problems to be solved by the device]

 However, in the case of the above-mentioned conventional technique, since the backup ring 107 has a shape in which the reinforcing ring 101 retains the axial movement, resistance is generated at the contact surface between the backup ring 107 and the reinforcing ring 101. However, it has a drawback that it is difficult to follow the eccentricity of the shaft (especially when it moves toward the outer diameter side and tries to return to the inner diameter side), which causes a problem that the sealing performance becomes unstable.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object thereof is to provide a sealing device capable of improving the eccentricity following property of the backup ring.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, in the present invention, a seal lip that comes into sealing contact with the outer peripheral surface of a movable shaft, a back-up ring that holds the seal lip when it is pressed, and the seal lip. In a sealing device including a holder to which a backup ring is attached, an elastic backup ring supporting portion having an elastic force that urges in a radial direction is provided in the holder.

[0006]

[Action]

 In the sealing device having the above configuration, the elastic backup ring support portion having the elastic force that urges in the radial direction prevents the backup ring from being restored due to the elastic force when the backup ring is pushed in by the shaft eccentricity. Workability and followability are improved.

[0007]

【Example】

 The present invention will be described below based on the illustrated embodiment. 1 to 4 showing a sealing device according to an embodiment of the present invention, reference numeral 1 denotes an annular seal lip integrally formed with a reinforcing ring 3 fitted to the inner circumference of a housing 2, and the seal lip 1 is made of rubber. It is formed of an elastic material such as. Further, the lip tip 4 having a wedge-shaped cross section provided on the inner peripheral side of the seal lip 1 is in sealing contact with the outer peripheral surface of the movable shaft 5, so that the fluid in the fluid to be sealed side O does not leak from the movable shaft 5 side to the atmosphere side A. Is configured. The fitting surface between the inner peripheral surface of the housing 2 and the seal lip 1 is also in a sealed state. A spring 6 is attached to the outer peripheral surface of the lip tip 4 to press the lip tip 4 toward the movable shaft 5.

An annular backup ring 8 is mounted in a holder 7 formed by an inner peripheral surface of the seal lip 1 near the atmosphere A and an end surface of the reinforcing ring 3 extending toward the movable shaft 5 on the fluid target side O to be sealed. Has been done. On the outer peripheral side of the backup ring 8, cutouts 81 having equal distribution of petals are provided. The notch 81 has a concave shape as shown in FIG. 3 (a) when viewed in cross section, and has a substantially rectangular surface on the side opposite to the movable shaft 5 as shown in FIG. 3 (b) when viewed in vertical section. As shown in FIG. 3 (c), the shape of the non-notched portion is a shape that follows the inner peripheral surface of the holder 7 of the seal lip 1. Further, the end surface of the notch portion 81 on the reinforcing ring 3 side projects toward the reinforcing ring 3 side in the axial direction from the end surface of the notch portion on the reinforcing ring 3 side. Then, the protruding portions of the notch 81 form grooves 82 equidistant to the contact surface with the reinforcing ring 3. Further, in the backup ring 8, when pressure is applied to the lip tip 4 from the fluid side O to be sealed, the lip tip 4 is deformed in the atmosphere side A direction and the sealing performance between the lip tip 4 and the movable shaft 5 is deteriorated. This is to prevent this from happening and is made of resin or the like.

On the other hand, ribs 9 that are equidistantly continuous with the seal lip 1 are formed of an elastic material such as rubber on the inner peripheral surface of the holder 7 of the seal lip 1. The surface of the rib 9 on the back-up ring 8 side is shaped along the outer peripheral surface of the cutout portion 81 of the backup ring 8, and the width thereof is almost the same as the width of the cutout portion 81 of the backup ring 8. ing. Then, the backup ring 8 is mounted in the holder 7 so that the ribs 9 in the holder 7 of the seal lip 1 fit into the notches 81 of the backup ring 8. At this time, the contact B between the notch 81 and the rib 9 is designed to have a interference, and the elastic force having an elastic force that urges in the radial direction by the interference and the rib 9 of the elastic material. It is the backup ring support portion 10.

In the sealing device having the above-described structure, the elastic backup ring support portion 10 and the rib 9 and the rib 9 elastically bias the backup ring 8 in the radial direction when the backup ring 8 is pushed in due to eccentricity. As a result, the force to return to the original works and the followability is improved.

Further, the groove 82 formed between the notches 81 reduces the frictional force between the reinforcing ring 3 and the back-up ring 8 and helps improve the followability.

Although the holder 9 of the seal lip 1 is formed by the inner peripheral surface of the seal lip 1 and the reinforcing ring 3 in the above embodiment, the holder 9 is not limited to the reinforcing ring. It can be applied similarly.

[0013]

[Effect of the device]

 The present invention has the above-described configuration and operation, and since the elastic back-up ring support portion is provided in the holder, the backup ring is elastically urged in the radial direction when it is pushed in due to axial eccentricity. Since the force to return is exerted, the followability can be improved and the stable sealing property can be obtained accordingly.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a sealing device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the sealing device of FIG.

3 (a) is a sectional view taken along the line XX of the main part of the sealing device in FIG. 2, and FIG. 3 (b) is a sectional view taken along the line YY of the backup ring in FIG. 3 (a). The figure (c) is the figure (a).
It is a ZZ sectional view of the backup ring of FIG. FIG. 3D is a partially cutaway perspective view of the backup ring.

FIG. 4 is a vertical cross-sectional view of a main part showing a rib.

FIG. 5 (a) is a vertical cross-sectional view of a conventional sealing device, and FIG. 5 (b) is a vertical cross-sectional view of a main part of FIG. 5 (a).

[Explanation of symbols]

 1 Seal Lip 2 Housing 3 Reinforcing Ring 4 Lip Tip 5 Movable Shaft 6 Spring 7 Holder 8 Backup Ring 81 Notch 82 Groove 9 Rib 10 Elastic Backup Ring Support

Claims (1)

[Scope of utility model registration request] 1. A seal lip that comes into sealing contact with an outer peripheral surface of a movable shaft, a backup ring that holds the seal lip when the seal lip is pressed, and a holder that mounts the backup ring provided on the seal lip. The sealing device according to claim 1, wherein an elastic backup ring support portion having an elastic force that urges in a radial direction is provided in the holder.