JPH072676U - Sealing device - Google Patents

Abstract

(57) [Summary] [Purpose] To extend the life of the seal and reduce friction between the movable shaft and the seal lip. [Structure] The backup ring 5 is characterized in that an inner peripheral surface is provided with a large roughness portion 51 having a roughened surface.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

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

[0002]

[Prior art]

 As a conventional sealing device of this type, for example, there is one shown in FIG. That is, the sealing device 100 seals a gap between the movable shaft 101 and the housing 102 which are concentrically assembled with each other, and is formed integrally with a reinforcing ring 103 fitted in the housing 102. The lip tip 105 of the seal lip 104 is brought into sealing contact with the outer peripheral surface of the movable shaft 101 by a spring 106 so that the fluid on the sealed fluid side O does not leak to the atmosphere side A.

A backup ring 107 is attached to the inner peripheral surface of the seal lip 104, so that when the pressure from the sealing fluid side O is generated, it is possible to prevent the deterioration of the sealing property caused by the deformation of the seal lip 104. It has become.

[0004]

[Problems to be solved by the device]

 However, there are many high-pressure sealing devices 100 with a backup ring 107 configured as described above from the past, and they have been mass-produced for power steering rods and the like by each automobile manufacturer. When acting on the lip 104, the backup ring 107 is compressed and contracted toward the inner diameter side by the force, and the movable shaft 101 is hugged. As a result, the sliding friction between the movable shaft 101 and the lip tip 105 becomes high, or The minute oil film on the surface of the movable shaft 101 was cut off, leading to poor lubrication, leading to a reduction in seal life.

The present invention was made in order to solve the above-mentioned problems of the prior art. The purpose of the present invention is to extend the life of the seal and reduce the friction between the movable shaft and the seal lip. It is to provide a sealing device to obtain.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, in the present invention, a sealing device having a seal lip that makes sealing contact with the outer peripheral surface of a movable shaft and a back-up ring that holds the seal lip when it is pressurized. In the above, the inner peripheral surface of the backup ring is provided with a large roughness portion having a roughened surface.

[0007]

[Action]

 In the sealing device configured as described above, since a large roughness is provided on the inner peripheral surface of the backup ring, a high pressure acts on the seal lip, and the force causes the backup ring to be pressed against the movable shaft. Most of the surface roughness plays the role of an oil sump, and an oil film is always maintained between the movable shaft and the backup ring. As a result, good lubricity can be maintained, and since good lubricity also prevents the backup ring from clinging to the movable shaft, the life of the seal is extended and friction between the movable shaft and the seal lip is prevented. It can be reduced.

[0008]

【Example】

 The present invention will be described below based on the illustrated embodiment. 1 shows a sealing device according to an embodiment of the present invention, 1 denotes a sealing device, which is an oil seal for a power steering ring rod of an automobile, rods which are concentrically and relatively movable to each other. The gap between the movable shaft 2 and the housing 3 is sealed.

The sealing device 1 is generally composed of a seal lip 4 and a backup ring 5 provided on the inner circumference of the seal lip 4.

The seal lip 4 is annular and is formed of an elastic material such as rubber, and is integrally provided with a reinforcing ring 6 that fits on the inner circumference of the housing 3. The lip tip 7 having a wedge-shaped cross section provided on the inner peripheral side of the seal lip 4 is in sealing contact with the outer peripheral surface of the movable shaft 2 so that the fluid on the sealing fluid O side does not leak to the atmosphere side A. Further, a spring 8 is mounted on the outer peripheral side of the lip tip 7, and the spring 8 presses the lip tip 7 toward the movable shaft 2.

The reinforcing ring 6 is a cylindrical member having a flange portion 61 extending inward in the radial direction, has an L-shaped cross section, and the rubber-like elastic body 9 is integrally provided on the outer peripheral surface of the cylindrical portion 62. Has been.

The cylindrical portion 62 of the reinforcing ring 6 is fitted and fixed to the inner peripheral surface of the housing 3 via the rubber-like elastic body 9, and the lip tip of the seal lip 4 integrally provided on the reinforcing ring 6 The end 7 is in sealing contact with the outer peripheral surface of the movable shaft 2 and is mounted between the housing 3 and the movable shaft 2.

Further, in the holder 10 formed by the inner peripheral surface of the seal lip 4 near the atmosphere side A and the end surface of the flange portion 61 of the reinforcing ring 6 extending toward the movable shaft 2 on the sealed fluid side O, An annular backup ring 5 is attached. In the backup ring 5, when the pressure from the sealed fluid side O is applied to the lip tip 7, the lip tip 7 is deformed in the atmosphere side A direction and the sealing property between the lip tip 7 and the movable shaft 2 is deteriorated. Is being prevented.

Then, on the inner peripheral surface of the backup ring 5, a roughened large portion 51 that has been subjected to a roughening process (pear-like texture) with a surface roughness of about 20 μm (preferably 10 to 40 μm) is provided near the sealed fluid side O. Further, there is provided a tapered portion 52 that expands from the large roughness portion 51 toward the atmosphere side A.

In the sealing device having the above-described configuration, the large roughness portion 51 is provided on the inner peripheral surface of the backup ring 5, and the taper portion 52 having a diameter increasing toward the atmosphere side A is provided on the atmosphere side A thereof. Therefore, when the high pressure acts on the seal lip 4 from the sealing fluid side O and the back-up ring 5 is pressed against the movable shaft 2 by the force, the large roughness portion 51 stores the oil which is the sealing fluid. The oil film is always maintained between the movable shaft 2 and the backup ring 5 to improve the lubricity.

Further, since the tapered portion 52 does not come into contact with the movable shaft 2, the contact width between the backup ring 5 and the movable shaft 2 is small and the oil film is less likely to run out, so that no lubrication failure occurs.

Further, since the diameter of the taper portion 52 is expanded toward the atmosphere side A, the oil is directed to the sealed fluid side O, so that both the lip tip 7 and the backup ring 5 are lubricated. It is possible to maintain good sex.

As described above, good lubricity can be maintained, and since good lubricity also prevents the backup ring 5 from being hugged by the movable shaft 2, the seal life can be extended and the movable shaft 2 can be prevented. The friction between the lip tip 7 and the lip tip 7 can be reduced.

In the above-described embodiment, the backup ring 5 is provided with the taper portion 52 on the inner peripheral surface thereof, but even if the taper portion is not provided, the lubricity is better than that of the prior art. Therefore, the taper portion may not be provided. .

[0020]

[Effect of device]

 The present invention has the above-described configuration and operation. Since the roughened portion is provided on the inner peripheral surface of the backup ring, high pressure acts on the seal lip, and the force pushes the back-up ring against the movable shaft. At this time, the large roughness of the inner peripheral surface plays the role of an oil sump, so that an oil film is always maintained between the movable shaft and the backup ring. As a result, good lubricity can be maintained, and since good lubricity eliminates the clinging of the back-up ring to the movable shaft, the life of the seal is extended and the friction between the movable shaft and the seal lip is reduced. It can be reduced.

[Brief description of drawings]

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

FIG. 2 is a vertical cross-sectional view of a conventional sealing device.

[Explanation of symbols]

 1 Sealing device 2 Movable shaft 3 Housing 4 Seal lip 5 Backup ring 51 Roughness part 52 Tapered part 6 Reinforcement ring 61 Flange part 62 Cylindrical part 7 Lip tip 8 Spring 9 Rubber-like elastic body 10 Holder

Claims (1)

[Scope of utility model registration request] 1. A sealing device comprising: a seal lip that comes into sealing contact with an outer peripheral surface of a movable shaft; and a backup ring that holds the seal lip when the seal lip is pressed. A sealing device provided with a large roughness portion having a roughened surface.