JPS584228B2 - Oil seal manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an oil seal, and more specifically, to a method of manufacturing an oil seal that improves sealing performance by improving the contact surface condition with a mating shaft by changing the cutting position.

Oil seals are used as leak prevention devices for lubricating oil, etc. in various rotating equipment.

This oil seal 1 usually has a lip portion 2 made of synthetic rubber, and is required to have stable sealing performance over a long period of time.

The surface of the lip portion 2 of the oil seal 1 that faces the mating shaft 4 usually consists of an oil side surface 7 and a seal surface 8 that are inclined in opposite directions.
is in sliding contact with the mating shaft 4 to prevent lubricating oil etc. from leaking to the outside.

The outer periphery of the lip portion 2 is provided with a spring shaft 6 into which a garter spring is inserted.

FIG. 1 is a cross-sectional view of the lip portion of an oil seal produced by a conventional manufacturing method. FIG. 2 is a cross-sectional diagram of the lip portion of an oil seal produced by the manufacturing method of the present invention. In the figure, the left side of oil seal 1 is the oil side; The right side is the atmosphere side.

In other words, oil tends to leak from the left to the right in the diagram.

To maintain the sealing performance of the oil seal, use Lip Edge 3.
In order to maintain the balance of the oil film interposed between the mating shaft 4 and the mating shaft 4, the sliding surface is rough, so-called satin-like, and the coefficient of friction is small, so that it easily adapts to the surface condition of the mating shaft 4, that is, unevenness. This is necessary.

The conventional method for manufacturing an oil seal shown in FIG. 1 is that when an oil seal 1 is molded and vulcanized using a mold, a burr 5 is formed to protrude from the tip of the oil side surface 7 of the lip portion 2 after the molding process. During the finishing step, the lip edge 3 is formed by cutting off the burr 5 using a cutting tool or the like.

Therefore, the cutting surface 9 where the rubber skin formed in the molding process is cut off as the burr 5 during the finishing process is formed at the tip of the oil side.

Therefore, since the sliding surface that contacts the shaft 4 is made of a rubber skin formed during the molding process, the sealing performance is unstable.

In the embodiment of the oil seal of the present invention, as shown in FIG. 2, when forming the lip portion 2, the mold structure of the tip of the lip portion is changed so that the burr 5 protrudes from the tip of the sealing surface 8. Using this as a conventional example, the lip edge 3 is formed by cutting off the burr 5 using a cutting tool or the like in the finishing process after the molding process.

Therefore, the cutting surface 9 where the rubber skin formed in the molding process is cut off as the burr 5 during the finishing process is formed at the tip of the sealing surface side 8.

Since the cutting surface 9 is configured as a contact surface with the mating shaft 4, a finely uneven surface can be formed on the sliding surface where the end surface of the filler compounded in the synthetic rubber is exposed.

As a result, the balance of the oil film interposed with the mating shaft 4 is maintained, and the sealing performance is improved.

Generally, the contact width of an oil seal is about 0.2 mm when new, and the contact width increases due to wear and deformation.
Since the direction in which wear progresses matches the cutting surface, stable sealing can be maintained over a long period of time.

In the embodiment, a radial lip type oil seal that contacts the shaft has been described, but the present invention is not limited to this, and the present invention is not limited to this. It is easy to understand that the present invention can also be applied to so-called side lip seals.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of an oil seal manufactured using a conventional manufacturing method.
FIG. 2 is a sectional view of an oil seal manufactured by the manufacturing method of the present invention. 1... Oil seal, 2... Lip portion, 3... Lip edge, 4... Mating shaft, 5... Burr, 6・・・・・・Spring groove, 7...
...Oil side, 8...Seal surface, 9...
...Cutting surface.

Claims (1)

[Claims] 1. During the molding process, a lip is provided at the tip of the oil seal lip so as to protrude from the tip on the seal surface side, and in the finishing process after the molding process, the lip edge is cut by cutting the lip edge to form a lip edge. A method for producing an oil seal, characterized in that the tip portion has a surface from which a rubber skin formed during a molding process has been removed.