JPH0446130Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an oil seal disposed between two members that are assembled concentrically with each other to make relative rotational motion. Regarding an oil seal equipped with.

(Prior art) 2 which are combined concentrically with each other to make relative rotational movement
2. Description of the Related Art Oil seals that are disposed between members and that provide a suction function for the fluid to be sealed by a screw action accompanying relative rotation are widely used.

The one shown in FIG. 4 is an example of this type of oil seal, in which a substantially triangular shape is placed on the sliding surface 2 of the seal portion 1 made of a rubber-like elastic material, as shown in detail in FIG. It has a cross-sectional shape of 1, and has screw-like protrusions 7 arranged at an angle with respect to the edge 3 of the sealing part 1, and the fluid to be sealed is sealed by the screw action of the screw-like protrusions 7 when the two members rotate relative to each other. This indicates the function of moving the cursor upward.

The one shown in FIG. 6 is another example of an oil seal with a suction function by screw action, in which a rubber-like elastic material such as tetrafluoroethylene resin material is used on the sliding surface 2 side of the seal portion 1. It is made of a material that is slightly harder and has excellent abrasion resistance and low friction compared to the threaded protrusion 7 shown in Fig. 7a or threaded thin threaded protrusion 7 shown in Fig. 7b. A thin sheet 8 with grooves 9 is attached, and the fluid to be sealed is moved upward in FIG. 6 by the screw action of the threaded protrusion 7 or threaded thin groove 9 when the two members rotate relative to each other. It is something.

(Problems to be Solved by the Invention) Among the threaded oil seals according to the conventional technology described above, in the example shown in FIG. Because it is molded with rubber-like elastic material,
Under severe wear conditions, the threaded protrusion 7
is worn out, resulting in a decline in sealing performance.

In the example shown in FIG. 6, a thin sheet 8 made of a material with excellent wear resistance is attached to the sliding surface 2 side of the seal portion 1. However, on the other hand, the thin sheet 8 is hard and the convex threaded projection 7 or the concave threaded narrow groove 9 does not cause premature wear on the sliding partner periphery. Since a gap is formed between the sealing surface and the surface, there is an unavoidable possibility that the fluid to be sealed may leak.

The object of the present invention is to solve the above-mentioned problems and provide an oil seal structure that can maintain good threading action over a long period of time without wear.

(Means for Solving the Problems) In view of the problems with the conventional oil seals described above, the oil seal of the present invention has a rubber-like elastic material on the sliding surface of the seal part. The rubber-like material is made of a harder material than the rubber-like elastic material, and has screw-like pieces arranged on the circumference at an angle to the edge of the seal part, and is sandwiched between the adjacent screw-like pieces. The surface of the elastic material portion and the surface of the threaded piece are formed on the same plane.

For the material of the screw-shaped piece embedded in the sliding surface of the seal part, a material with excellent wear resistance and low friction properties, such as tetrafluoroethylene resin material, is suitable. To embed the screw-shaped piece in the sliding surface, for example, prepare a material in which a strip-shaped piece, a rod-shaped piece, etc. is attached at an angle to the ring by punching a disc-shaped sheet or by injection molding. However, when forming the seal part, this can be easily carried out by superimposing a rubber-like elastic material for the seal part on the raw material and applying pressure and heating.

(Function) In the oil seal having the above configuration, the screw-like pieces and the rubber-like elastic material portions arranged alternately on the sliding surface of the seal part have a sliding effect caused by the difference in hardness between them. Due to the difference in contact pressure with the target circumferential surface and the difference in surface roughness, a screw action occurs during relative rotation and a suction action on the fluid to be sealed, and the screw-shaped piece made of a hard material
Prevents wear of rubber-like elastic material parts due to sliding.

(Embodiment) In the embodiment shown in FIG. 1, the sliding surface 2 of the seal part 1 is made of a rubber-like elastic material, and the sliding surface 2 of the seal part 1 is made of a tetrafluoroethylene resin material. Screw-shaped pieces 4 arranged circumferentially at an angle with respect to the edge 3 are embedded.

Sliding surface 2 of seal portion 1 in the above embodiment
As shown in FIG. 2, a large number of threaded pieces 4 are attached to the ring 5 at an angle with respect to the circumferential direction from a tetrafluoroethylene resin sheet. When preparing and molding an oil seal using a rubber-like elastic material, the above-mentioned tetrafluoroethylene resin material is applied to the mold for forming the sliding surface 2, and the rubber-like elastic material is further layered and the mold is pressurized.・By heating, as shown in Figure 3,
This can be easily carried out by embedding a material made of tetrafluoroethylene resin material in the sliding surface 2 of the seal part 1 and cutting off the remaining material as shown by the two-dot chain line in the figure. The piece 4 and the rubber-like elastic material portion sandwiched between the threaded pieces 4 share the same surface.

(Effects of the invention) As described above, the oil seal of the invention is made of a material that is harder than the rubber-like elastic material on the sliding surface of the seal portion that is molded from the rubber-like elastic material. By having a structure in which screw-like pieces arranged obliquely with respect to the edge of the seal part are buried, the screw-like pieces and the rubber-like elastic material are alternately arranged on the sliding surface of the seal part. The difference in contact pressure against the sliding surface caused by the difference in hardness between the parts and the difference in surface roughness between the two parts causes a screw action during relative rotation between the sliding surface of the seal part and the mating peripheral surface. Since the suction function for the fluid to be sealed is ensured, and since the threaded pieces and the rubber-like elastic material parts arranged alternately share the same surface, the rubber-like elastic material part of low hardness is attached to the hard screw. Since it comes to be supported by the shaped piece, abrasion of the sliding surface is prevented and normal sealing function is maintained over a long period of time.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of one embodiment of the present invention, Figure 2 is a plan view of the material used to manufacture the embodiment of Figure 1, and Figure 3 shows the manufacturing process of the embodiment. 4 is a sectional view of an example of a conventional oil seal, FIG. 5 is a partial sectional view at the position indicated by an arrow in FIG. 4, and FIG. 6 is a sectional view of an example of a conventional oil seal. Cross-sectional view of other examples of oil seals according to technology,
FIG. 7 is a partial sectional view at the position indicated by the arrow in FIG. 6. 1...Seal part, 2...Sliding surface, 3...Edge,
4... Threaded piece, 5... Ring, 7... Threaded projection 7, 8... Thin sheet, 9... Threaded thin groove.

Claims (1)

[Scope of utility model registration request] Seal part 1 molded with rubber-like elastic material
The sliding surface 2 is made of a material harder than the rubber-like elastic material, and the edge 3 of the seal portion 1 is made of a material harder than the rubber-like elastic material.
The screw-like pieces 4 arranged on the circumference at an angle to Oil seal formed on the surface.