JPH06105104B2 - Oil seal and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an oil seal for preventing oil from leaking in a rotary motion part and a reciprocating part, and a manufacturing method thereof.

[Conventional technology]

Conventionally, in order to improve the durability of the oil seal and the sealing function, for example, a thin fluorocarbon resin ring is formed on the surface portion of the seal lip of an annular seal member made of an elastic material such as rubber. Adhesion of the film lip of is performed.

The formation of this film lip and the adhesion to the lip member have been performed as follows.

First, as shown in FIG. 5 (a), a cylindrical or cylindrical billet 1 made of fluororesin, which is a fluororesin such as tetrafluoroethylene resin mixed with a filler such as graphite powder or carbon powder, is fired. To be done. Next, the thin plate 2 made of fluororesin is produced from the billet 1 by cutting. That is, as shown in FIG. 5 (b), the billet 1 is skived to form a thin plate 2 made of fluororesin having a thickness of about 0.1 to 0.5 mm. Next, as shown in FIG. 5 (c), the thin plate 2 is subjected to a drawing process to form a large number of protrusions 3, 3 ... Of substantially the same shape as the coating lip. Next, each convex portion 3 is extracted from the thin plate 2 in a shape substantially similar to that of the film lip, and then the adhesive 7 is applied to the surface of the convex member 3 to be bonded to the surface of the seal lip 6 of the seal member 4. Fig. 5 (d)
As shown in FIG. 5, the mold 5 is installed at a predetermined position in the cavity 10 for molding the seal member 4. At this time, the metallic annular outer shell member 9 is also incorporated in the cavity 10 at a predetermined position. Next, as shown in FIG. 5 (e), a molten rubber member, which is the material of the seal member 4, is pressure-injected into the cavity 10, the coating lip 8 is adhered to the seal lip 6, and these are demolded. After that, unnecessary portions of the rubber member and the upper end of the thin plate 2 are cut off along the cutting line XX.

Further, in the past, in order to obtain the thin plate 2 made of fluororesin from the billet 1, the billet 1 was cut off in the radial direction as required to manufacture the circular thin plate 2.

[Problems to be Solved by the Invention]

However, since the thin plate 2 made of fluororesin, which is the material of the coating lip 8, is manufactured by cutting the billet 1 in the related art, surface roughness due to cutting occurs on the surface of the thin plate 2 and the billet 1 Unevenness occurs due to the particle size of the filler such as graphite powder and carbon powder mixed in the inside, and pinholes also occur in the extreme case. As described above, since the conventional film lip 8 is formed of a material having a large surface roughness and uneven unevenness, the amount of oil stored in the concave portion of the surface of the film lip 8 is the circumference of the actual seal portion. It was uneven in the direction. Therefore, in the seal portion formed by the film lip 8, the oil film for lubrication formed between the film lip 8 and the outer peripheral surface of the shaft becomes uneven in the circumferential direction, and particularly when the shaft reciprocates, the oil is scraped out. The amount will be uneven,
It was an incomplete seal. In addition, the coating lip 8 is worn unevenly in the circumferential direction, and the wear rate is high,
The coating lip 8 had poor durability and a short life.

The present invention has been made in view of these points, the surface of the film lip adhered to the seal member is smooth,
It has excellent conformability at the initial stage of operation, and can form an oil film for lubrication evenly in the circumferential direction of the seal portion of the film lip, and especially during reciprocation, the amount of oil scratched out is also uniform, resulting in a very good seal. It is an object of the present invention to provide an oil seal having excellent wear resistance and a long life, and a method for manufacturing the oil seal that can manufacture the oil seal extremely easily.

[Means for Solving the Problems]

The oil seal of the present invention is an oil seal in which a thin fluororesin annular film lip is adhered to a surface portion of an annular seal lip of a seal member, and a fluororesin, an adhesive and a solvent are applied to the surface of the film lip. The contained fluororesin coating film is formed to have a hardness lower than that of the fluororesin material of the film lip.

The method for producing an oil seal of the present invention comprises forming a thin plate made of a fluororesin into a substantially film-lip shape, and a surface which is one surface of the film lip and which is bonded to the surface portion of the annular seal lip of the seal member. To the other surface, a fluororesin coating containing fluorine resin, an adhesive and a solvent is applied to the other surface, and this film lip is built in a predetermined position in the cavity of the mold for oil seal molding, and then The material forming the seal member is injected under pressure into the cavity and heated to form the seal member, and at the same time, the coating lip is vulcanized and adhered to the surface of the seal lip of the sealing member, and the surface of the coating lip is The fluororesin coating material is fired to form a fluororesin coating film having a hardness lower than that of the fluororesin material of the coating lip.

[Action]

In the oil seal of the present invention, a fluororesin coating film containing a fluororesin, an adhesive and a solvent on the surface of the film lip adhered to the surface side of the seal lip of the seal member is lower than the hardness of the fluororesin material of the film lip. Since it is formed with hardness, the surface of the film lip is smooth, there is no unevenness or pinhole as in the past, and it makes uniform contact with the outer peripheral surface of the shaft and the inner peripheral surface of the cylinder in the circumferential direction. In the initial stage of exercise, the fluororesin coating film is worn so as to maintain good conformability, and the thin plate fluororesin material portion which is the base material of the coating lip and the outer peripheral surface of the shaft or the inner peripheral surface of the cylinder are The initial familiarity with is extremely excellent. In addition, the oil film for lubrication formed between the film lip and the outer peripheral surface of the shaft is also uniform in the circumferential direction, and especially during reciprocating movement, the amount of oil scraped out is also uniform in the circumferential direction, and a good seal is provided. It In addition, since uneven wear of the coating lip does not occur, durability is improved and life is extended.

Further, according to the manufacturing method of the present invention, a film lip to be adhered to the surface of the seal lip of the seal member, an adhesive is applied to the surface to be adhered to the seal lip, and a fluororesin is applied to the surface side of the film lip. The coating material is built into the mold cavity, and the material of the seal member is injected under pressure into the cavity to form a highly effective fluororesin coating film on the surface of the film lip as described above. can do.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

1 to 3 show the case where the oil seal of the present invention is applied to the valve stem seal 11.

This valve stem seal 11 is used as an oil seal for the valve stem 12 portion of the intake and exhaust valves arranged in the cylinder head of the engine. The valve stem 12 is reciprocally inserted into a stem guide 13 fitted to the cylinder head, and a valve stem seal 11 is attached to the upper end of the stem guide 13 to provide an outer circumference of the valve stem 12. Prevents oil from leaking from the part.

Explaining this valve stem seal 11 further, the outermost metal outer shell member 14 has a substantially cylindrical shape with an inner flange 15 formed at the upper end thereof, and the rubber is provided inside the outer shell member 14. A seal member 16 made of an elastic material such as is baked to be integrally formed. An annular projection 18 that engages with an annular engagement groove 17 formed at the upper end of the stem guide 13 is provided at a position of the seal member 16 that contacts the inner side of the outer shell member 14. A substantially cylindrical seal lip 19 is formed so as to extend upward from the inner end position of the inner flange 15 of the member 14. A lip end portion 20 is formed on the inner peripheral surface near the upper end portion of the seal lip 19 so as to project inward in a mountain shape and make the strongest contact with the outer peripheral surface of the valve stem 12. Then, the valve stem of the seal lip 19 of the seal member 16
A coating lip 21 made of a fluororesin is adhered to the inner peripheral surface portion which is to come into contact with 12. A fluororesin coating film 22 is formed on the surface side of the film lip 21, that is, the surface that contacts the valve stem 12.

Next, a method of manufacturing the valve stem seal 11 configured as above will be described.

First, as shown in FIG. 4 (a), a thin plate made of fluororesin
Prepare 2a. As the thin plate 2a, a thin plate 2a made of a fluororesin billet 1 mixed with various fillers by a cutting means such as skiving or parting is used as in the conventional case.

Next, as shown in FIG. 4 (b), the thin plate 2 is subjected to a drawing process, and a large number of convex portions having substantially the same shape as the coating lip 21 are formed.
Form 3a, 3a.

Next, as shown in FIG. 4 (c), of the both surfaces of the convex portion 3a, the surface to be adhered to the seal lip 19 portion of the seal member 16 (the upper surface side in the figure) is In order to improve the adhesive performance with the seal lip 19, the entire surface is uniformly roughened by etching or the like.

Next, as shown in FIG. 4 (d), a fluororesin coating agent 23 composed of a mixture of fluororesin powder, an adhesive and a solvent is uniformly applied to the other surface of both sides of the convex portion 3a, Convex part 3a
The unevenness of the surface is covered with the fluororesin coating agent 23 to form a smooth surface.

Next, the seal member 16 is applied to the surface of the convex portion 3a that is uniformly roughened.
Adhesive 24 for adhering to the seal lip 19 is applied, and each convex portion 3a is extracted from the thin plate 2a in the same shape as the coating lip 21, and the fourth
As shown in FIG. 6E, the seal member 16 of the mold 25 is installed at a predetermined position in the cavity 26 for molding. At this time, the outer shell member 14 is also incorporated in the cavity 26 at a predetermined position. Next, as shown in FIG.
A rubber member, which is a material of the seal member 16, is melted and pressurized and injected therein, and is heated to 150 to 350 ° C., for example. As a result, the adhesive 24 between the seal lip 19 and the convex portion 3a injection-molded in the cavity 26 and the seal lip 19 itself are vulcanized and both are extremely vulcanized and bonded, and at the same time, the convex portion 3a is formed. The fluororesin coating agent 23 applied to the surface of the is baked to form the fluororesin coating film 22. The hardness of the fluororesin coating film 22 may be set lower than the hardness of the fluororesin material of the coating lip 21 in order to improve the initial conformability.

Next, these are released from the mold 25, and unnecessary portions of the rubber member and the upper end portion of the thin plate 2a are cut off along the cutting line YY to manufacture the valve stem seal 11.

Next, the operation of the valve stem seal 11 of this embodiment manufactured in this way will be described.

In this embodiment, as shown in FIG. 1, since the fluororesin coating film 22 is formed on the surface of the film lip 21 adhered to the surface side of the seal lip 19 of the seal member 16, the film lip is formed. The surface of 21 is smooth, and there is no unevenness or pinhole as in the past. When this valve stem seal 11 is attached to the stem guide 13 and the valve stem 12 is inserted, it comes into uniform contact with the outer peripheral surface of the valve stem 12 in the circumferential direction. At the beginning of the reciprocating movement of the valve stem 12 for the first time after assembly, the fluororesin coating film 22 is worn so as to maintain good conformability and becomes as shown in FIG. The initial compatibility between the fluororesin material portion of the thin plate 2a, which is a material, and the valve stem 12 is extremely excellent. Also, the film lip 21
The oil film for lubrication that is formed between the outer surface of the bubble stem 12 and the bubble stem 12 is also uniform in the circumferential direction, and the amount of oil scratched out when the hubble stem seal 12 reciprocates is also uniform in the circumferential direction. Is applied. Further, uneven wear does not occur on the film lip 21, so that durability is improved and life is extended.

The oil seal of the above embodiment is a bubble stem seal 11 that seals against a reciprocating bubble stem 12.
However, the present invention can also be used as a seal for a rotating shaft, and can also be favorably applied to an oil seal having a seal lip formed radially outward.

The present invention is not limited to the above embodiment,
It can be changed if necessary.

〔The invention's effect〕

Since the oil seal and the method for producing the same of the present invention are configured and operate as described above, the surface of the film lip adhered to the seal member is smooth and excellent in the conformability at the initial stage of operation. An oil film for lubrication can be formed evenly in the circumferential direction of the seal part of, and especially when the shaft or the like reciprocates, the amount of oil scraped out is also uniform, and extremely good sealing can be performed, and wear resistance can be improved. The oil seal has excellent properties and has a long life, and the oil seal can be manufactured very easily.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 3 are vertical sectional views of an embodiment in which the oil seal of the present invention is applied to a valve stem seal, and FIG.
FIG. 3 is an enlarged view of the II part of the figure, FIG. 3 is a view similar to FIG. 2 after initial familiarization, and FIGS. 5A to 5E are views showing steps of the conventional manufacturing method. 11 …… Bubble stem seal, 12 …… Bubble stem, 16…
… Seal member, 19 …… Seal lip, 20 …… Lip end, 21 …… Film lip, 22 …… Fluorocarbon resin coating, 23 ……
Fluororesin coating, 24 ... Adhesive, 25 ... Mold, 26 ...
cavity.

Claims (2)

[Claims] 1. An oil seal in which a thin fluororesin annular film lip is adhered to a surface portion of an annular seal lip of a seal member, and fluorine containing a fluororesin, an adhesive and a solvent is applied to the surface of the film lip. An oil seal, wherein the resin coating film has a hardness lower than that of the fluororesin material of the coating lip. 2. A thin plate made of fluororesin is formed into a substantially film-lip shape, and an adhesive is applied to one surface of the film lip, which is bonded to the surface portion of the annular seal lip of the seal member. Then, the other surface is coated with a fluororesin coating containing a fluororesin, an adhesive and a solvent, and this film lip is built in a predetermined position in the cavity of the oil seal molding die, and then the sealing member is formed. The material to be pressurized is injected into the cavity and heated to form a sealing member and at the same time vulcanize and bond the coating lip to the surface of the sealing lip of the sealing member, and to coat the surface of the coating lip with the fluororesin coating agent. A method for producing an oil seal, comprising forming a fluororesin coating film by baking to a hardness lower than that of the fluororesin material of the film lip.