JP2000009236A - Oil seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil seal that holds improved adhesion of a lubricative resin layer made of fluororesin to its seal lip part and thus avoids peeling of the lubricative resin layer to the utmost even when used under severe conditions. SOLUTION: A seal lip part 2 is provided with a fluorinated layer 6 on its surface coated with a lubricative resin layer 5. This improves the wettability between the elastic material of the seal lip part 2 and the lubricative resin layer 5 of fluororesin and causes the fluorinated layer 6 having an intermediate characteristic between the elastic material and fluororesin to act as a gradient effect layer to thereby suppress the effect of swelling and temperature on them and avoid their peeling to the utmost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal, and more particularly to an oil seal having a seal lip coated with a lubricating resin.

[0002]

2. Description of the Related Art In an oil seal, generally, a seal lip portion made of an elastic material such as rubber comes into contact with a mating member to obtain a sealing property. Conventionally, as shown in a sectional view of FIG. , Seal lip 2 and mating member S
In order to reduce the friction torque with the seal lip 2 and coat the lubricating resin layer 5 on the seal lip 2 in order to improve the wear resistance (for example, Japanese Utility Model Publication No.
7-27961).

The resin forming the lubricating resin layer 5 includes:
Fluorine-based resins such as polytetrafluoroethylene (PTFE) resin are frequently used.

[0004]

Incidentally, in the oil seal coated with the lubricating resin layer 5 as described above, if the degree of adhesion of the lubricating resin layer 5 is insufficient, it may be peeled off depending on the use conditions. Sometimes. In particular, oil that easily swells the rubber that is the material of the seal lip portion 2,
There is a problem that the oil containing an additive that reacts with rubber easily peels off when used at a high temperature. Conventionally, in order to increase the degree of adhesion of the lubricating resin layer 5 to the seal lip portion 2, the coated surface of the seal lip portion 2 is washed with a solvent or the like prior to the coating process of the lubricating resin layer 5. However, the above-mentioned problems have not been completely solved.

It is an object of the present invention to improve the degree of adhesion of a lubricating resin layer made of a fluororesin to a seal lip.
Accordingly, it is an object of the present invention to provide an oil seal in which the lubricating resin layer is hardly peeled off even when used under severe conditions or the like.

[0006]

The structure for achieving the above object will be described with reference to FIG. 1 showing an embodiment. The oil seal according to the present invention comprises a seal lip 2 made of an elastic material. An oil seal coated with a lubricating resin layer 5 made of a fluororesin is characterized in that a fluorinated layer 6 is formed on a surface of the seal lip portion 2 to be coated with the lubricating resin layer 5.

According to the present invention, the wettability between the two materials is achieved by forming an intermediate material layer between the elastic material forming the seal lip portion 2 and the lubricating resin layer 5 therebetween. At the same time, the intended effect is to be achieved by obtaining the intervening effect of the functionally graded layer.

That is, by forming the fluorinated layer 6 on the surface of the elastic material forming the seal lip portion 2,
The joint surface with the lubricating resin layer 5 has similar characteristics to the fluorine-based resin forming the resin layer 5, so that the wettability is improved and the adhesion after coating is improved.

Further, the fluorinated layer 6 obtained by fluorinating the elastic material forming the seal lip portion 2 has a material layer having an intermediate characteristic between the elastic material as the base and the lubricating resin layer 5 with respect to the fluorine component. Therefore, it functions as a functionally graded layer, and the effects of external factors such as swelling of the elastic material by oil and changes in environmental temperature are reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main part showing a configuration of an embodiment of the present invention.

An inwardly protruding seal lip 2 is integrally formed with a seal body 1 formed of an elastic material such as rubber into an annular shape, and a reinforcing metal core 3 is fixed thereto. A garter spring 4 is fitted around the outer periphery of the seal lip 2.

The sliding surface of the seal lip portion 2 with the mating member S is coated with a lubricating resin layer 5 made of a fluorine-based resin such as PTFE. A fluorinated layer 6 is formed on the surface of the seal lip 2 to be coated with the lubricating resin layer 5. Therefore, the lubricating resin layer 5 comes into contact with the seal lip portion 2 via the fluorine treatment layer 6.

The fluorine-treated layer 6 is formed, for example, by reacting a desired portion of the seal body 1 with a fluorine gas in a fluorine atmosphere while exposing the required portion of the seal body 1 or by spraying a fluorine gas on the required portion of the seal body 1. Can be formed by The thickness of the fluorine treatment layer 6 is several μm.
Degree.

The lubricating resin layer 5 comprises a fluorine-treated layer 6
Can be formed by bonding a PTFE sheet to the surface of the resin, or by applying and curing a molten PTFE resin.

According to the above-described embodiment of the present invention, the fluorine-treated layer 6 has a higher affinity for the fluorine-based resin than the elastic material itself such as rubber forming the seal lip portion 2. In addition, the wettability between the two is improved, and the lubricating resin layer 5 is highly adhered to the seal lip portion 2 and hardly peels off.

The fluorine treatment layer 6 has an intermediate property between the elastic material forming the seal lip portion 2 and the lubricating resin layer 5 with respect to the fluorine component. Therefore, it is possible to alleviate the influence of oil swelling and environmental temperature between them.

In the above embodiment, the radial type oil seal has been described. However, the present invention is not limited to this, and is widely applied to an oil seal having a seal lip portion which is in sliding contact with a mating member. Needless to say, the shape of the seal body and the core metal, the presence or absence of the garter spring, and the like are not particularly limited.

[0018]

As described above, according to the present invention, since the fluorine-treated layer is formed on the surface of the seal lip to be coated with the lubricating resin layer made of the fluororesin, the lubricity of the seal lip is improved. Improved wettability of the resin layer,
At the same time as the degree of adhesion between the two increases, the fluororesin layer acts as a functionally graded layer, and if the elastic material forming the seal lip swells with oil or expands due to use at high temperatures, the effect is not affected. Since the lubricating resin layer is relaxed, the lubricating resin layer is less likely to peel off as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a conventional oil seal in which a lubricating resin layer is formed on a seal lip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Seal main body 2 Seal lip part 3 Core 4 Garter spring 5 Lubricity resin layer (fluorine resin) 6 Fluorine treatment layer

Claims (1)

[Claims] 1. An oil seal in which a seal lip portion made of an elastic material is coated with a lubricating resin layer made of a fluororesin, a fluorine-treated layer is formed on a surface of the seal lip portion to be coated with the lubricating resin layer. An oil seal characterized in that: