JPH0425106B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the sealing properties of oil seals, and more specifically to a method for surface treatment of oil seals.

Conventionally, oil seals have a seal lip made of an elastic material such as synthetic rubber, and the tip of the seal lip comes into sliding contact with a mating shaft to prevent lubricating oil from leaking to the outside. However, if the tip of the seal lip is too well finished to the mating shaft, lubricity will be reduced, and the tip will generate heat due to rotational friction, resulting in seizure and poor sealing.
On the other hand, if the tip of the seal lip is rough, it may cause oil leakage and impair sealing performance. In order to maintain the sealing performance of this oil seal, the seal lip surface and the contact surface of the mating shaft need to have an appropriate roughness with a gap in a certain range. In other words, if the roughness is too small, it will cause local heat generation due to sliding, resulting in hardening or seizure, while if the roughness is too large, it will cause leakage or wear. In the case of a rotary seal, a maximum roughness Rmax of about 0.7 to 3.0 s is preferable for sealing, but it varies depending on the usage condition and size of the seal. Therefore, as long as the roughness is within a suitable range, the seal lip contact area has a low coefficient of friction, maintains a good oil film balance, and easily adapts to the mating shaft to provide a strong seal for a long period of time. Therefore, in order to form this appropriate range of roughness on the seal lip, for example, there is a method of cutting the tip of the seal lip with a cutting tool or the like to form a groove, a method of cutting the circumferential tip of the seal lip with a knife, or a method of forming an uneven part on the mold in advance. Attempts have been made to form an appropriate roughness on the seal lip skin surface using a molding method or the like. However, all of the above-mentioned methods have drawbacks such as being extremely poor in mass production, requiring special jigs for exclusive use, and requiring special skill to operate.

The present invention provides a surface treatment method for oil seals that eliminates these drawbacks, provides high sealing performance, and is suitable for mass production.

A detailed description will be given below with reference to the drawings.

As shown in the figures, the present invention is a surface treatment method for an oil seal A formed of an elastic body such as synthetic rubber or synthetic resin and interposed between a rotating side member and a stationary side member. This is a surface treatment method for an oil seal A in which particles 1 made of a hard material such as steel balls or glass balls having an appropriate particle size are sprayed onto the entire surface.

This treatment method has the following features and exhibits an excellent sealing effect. That is, by spraying granules 1 having an appropriate particle size that are jetted in a certain direction onto the sealing surface of oil seal A, the granules 1 reach the surface of the sealing surface and the sealing surface is covered with particles 1. Each of them knocks. At this time, the seal surface succumbs to the impact of the injected particles 1 and gradually destroys the film on the surface that each particle 1 touches, forming an uneven shape. Furthermore, since the sealing surface of the oil seal A is made of an elastic material that alleviates the impact force of the injected particles within a desirable range, the troughs of the uneven portions formed on the surface of the oil seal A reduce the impact force beyond a certain level. It works to slow down the progression of depth and destroy the protruding peaks, forming an ideal finely uneven surface with a satin finish. In addition, by making particles 1 of any size, it is possible to control the uneven shape to a desired roughness, and it is now possible to easily form the optimum roughness for sealing on the sealing surface of oil seal A. .

In the case of oil seal A made of synthetic rubber, etc., the effect of finely destroying the coating on the seal surface is that the end face of the filler compounded in the synthetic rubber is exposed, and each of the exposed fillers is on the rotating side. When the oil seal A is installed at the location to be sealed and is operated, the seal surface always has a well-balanced and moderate oil film. Since it is held in place, it can easily fit into the mating shaft and maintain good sealing performance for a long period of time.

In addition, in this surface treatment method, it is possible to provide a desired roughness and a large amount of processing capacity by changing the shape, particle size, particle amount, ejection time, etc. of the nozzle 2 that ejects the granules 1, and further improve elasticity. Compared to the conventional lip cut method or lip cutting method, many seals can be processed at the same time, allowing for a wider processing work, such as being able to finish the mold marks such as burrs that are unavoidable when forming the body. This greatly improved mass productivity by shortening time and reducing manufacturing costs.

In addition, this surface treatment method allows the formulation of the base material to be given sufficient consideration to many important items such as heat resistance and weather resistance, rather than being limited only to sealing power. Similarly, it is possible to design an optimal shape that satisfies the above-mentioned important items.

As explained above, the present invention is an ideal oil seal that can easily and quickly form a satin-like seal surface that is most suitable for sealing, which has not been seen in conventional oil seals, and in large quantities. This is a surface treatment method for seals.

[Brief explanation of drawings]

The drawing is a perspective view of injecting the granules of the present invention onto an oil seal. A...Oil seal, 1...Particle, 2...Nozzle.

Claims (1)

[Claims] 1 In an oil seal formed of an elastic body such as synthetic rubber or synthetic resin that is interposed between a rotating side member and a stationary side member and sealing both members; particles formed of a hard material on the seal surface or the entire surface of the oil seal. A surface treatment method for oil seals characterized by strongly radiating the body and creating a satin finish with fine irregularities on the surface.