JPH0314969A - Sealing device and its manufacture - Google Patents

Abstract

PURPOSE:To enable seal contact slidably for sealing between a shaft and the inside of housing by providing a taper part gradually reduced in its diameter toward the atmospheric side in the axial direction, at the atmospheric side end of metal ring for fitting an outer circumferential metal face to the inside of housing. CONSTITUTION:A taper part 4 is provided, which is gradually reduced in its diameter toward the axial atmospheric side A, at the atmospheric side end of an outer diameter part 15, and at the tip end of the tapered part 4, an inward flange part 5 is continously formed. The whole atmospheric side end of the inward flange part and the tapered part 4 is coated with a rubber part 7 pro vided at the outer peripheral part of the tapered part 4. A main lip 13 made of rubber resilient member is elongated to a fluid side to be sealed from the inner end of the inward flange part 5. In setting oil sealing, the rubber part 7 is fitted in a housing 16 prior to the outer diameter part 15 of metal face, and thus the outer diameter part 15 can be guidedly inserted by means of the rubber resilient body without generation of biting or scratch groove.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a sealing device such as an oil seal used in various shaft seals, particularly a device in which a metal surface is exposed at the outer circumferential fitting portion, and a method for manufacturing the same. .

(Prior Art) As a conventional sealing device of this type, there is one shown in FIG. 6, for example. That is, 100 is a peripheral metal type oil seal in which the metal surface is exposed at the outer peripheral fitting portion, and is composed of a metal ring 101 and a seal lip 102 made of a rubber-like elastic body that is integrally baked on the metal ring 101. It is configured.

Conventionally, such an oil seal 100 has been generally manufactured by insert molding, in which a metal ring 101 is inserted into a mold, a rubber dough is filled in the mold, and the mold is integrally vulcanized. The metal ring 101 has an L-shaped cross section and is positioned by bringing its outer peripheral surface into contact with the inner wall surface of the oval-shaped cavity.

(Problem to be Solved by the Invention) However, in the case of the above-mentioned prior art, the metal ring 10
A gap was created between the outer periphery of the mold and the inner wall surface of the mold, and the rubber fabric sometimes got into the gap due to the molding pressure.

If such rubber material gets inside, it becomes impossible to obtain a strong metal fitting with the housing, which is a characteristic of the outer metal type seal. Therefore, it is necessary to remove the rubber fabric that has wrapped around the outer periphery of the metal ring 101 after the molding is completed, resulting in a problem of poor production efficiency.

Therefore, it is possible to eliminate the gap by bringing the metal ring 101 into close contact with the inner wall surface of the mold, but it is impossible to eliminate the gap due to variations in dimensional accuracy and the like. Also,
If the fitting force is increased too much, it will be difficult to release the mold, and there is also a risk that the metal ring 101 will be deformed, making it impossible to obtain the desired sealing performance.

The present invention was made in order to solve the problems of the prior art described above, and its purpose is to provide a sealing device and a method for manufacturing the same that can prevent molding material from going around the outer periphery of a metal ring during molding. It is about providing.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a seal between a housing and a shaft that are assembled concentrically and relatively movably, and the outer peripheral metal surface of the housing A sealing device comprising a metal ring fitted on the inner periphery and integrally provided with a sealing member made of a rubber-like elastic body that makes sealing contact with a shaft, the metal ring having an axial direction at an atmospheric side end portion of the metal ring. It is characterized by having a tapered portion that gradually becomes smaller in diameter toward the atmosphere.

Further, in the method for manufacturing a sealing device of the present invention, a metal ring is inserted into an annular cavity provided inside a mold along its central axis direction, and the outer diameter is gradually increased at the tip of the metal ring in the insertion direction. A tapered portion is provided so as to become smaller, and the tapered portion is brought into liquid-tight contact with the inner wall facing the cavity of the mold,
Using the wedge effect of the tapered part, the molding pressure of the molding material filled into the cavity causes the tapered part to bite into the inner wall of the mold, increasing the contact surface pressure and filling the molding material to perform molding. Configured.

(Function) According to the above-mentioned sealing device and its manufacturing method, the wedge action of the tapered part of the metal ring inserted into the mold can prevent the molding material from going around to the outer circumferential side of the metal ring during molding. .

(Example) The present invention will be explained below based on the illustrated example. Fourth
A sealing device according to an embodiment of the present invention is shown in the figures and FIG. This sealing device is a so-called peripheral metal type oil seal similar to the conventional example, and is generally composed of a metal ring 1 and a main lip 13 constituting a sealing member made of a rubber-like elastic body. The metal ring 1 has a substantially L-shaped cross section, and has an outer diameter part 15 on its outer periphery with an exposed metal surface that metal-fits into the mating housing 16. Tapered portion 4 that gradually becomes smaller in diameter toward the atmosphere side A in the axial direction
Further, an inward flange portion 5 is continuously formed at the tip of the tapered portion 4. A rubber portion 7 serving as a sealing member that is in fluid-tight contact with the housing 16 is provided around the entire outer periphery of the tapered portion 4 . This rubber portion 7 has an R portion 9 between the tapered portion 4 and the outer diameter portion 15.
An annular recess 8 is formed at a portion where the outer periphery of the recess 8 extends from a tangent to the tapered portion 4 . The rubber portion 7 covers the entire circumference of the tapered portion 4 and the end face of the inward flange portion 5 on the atmosphere side, and a dust lip 14 as a sealing member is continuously formed on the inner circumference as necessary. Ru. Furthermore, the above-described main lip l3 made of a rubber-like elastic body extends from the inner end of the inward flange portion 5 to the side O of the fluid to be sealed. A spring 12 is attached to this main lip 13 as necessary. On the other hand, the O end edge of the outer diameter portion 15 on the fluid side to be sealed is bent inward. This bent end 3
and the outer diameter portion l5 are continuous at R, and the metal housing 1
6.It has a smooth shape that prevents galling with the inner circumference. A gasket portion 10 made of a rubber-like elastic material is provided on the outer periphery of this bent end portion 3 as a sealing member that fits fluid-tightly into the inner periphery of the housing 16. In addition, all parts of the metal ring l that face the fluid to be sealed are covered with a rubber-like elastic material to enhance corrosion resistance. This anti-corrosion rubber part 11 is continuous with the gasket part 10, and is also continuous with the main lip 13 mentioned above. Therefore, in this oil seal, only the outer diameter portion 15 of the outer periphery of the metal ring 1 has a metal surface exposed, and the rest is entirely covered with a rubber-like elastic body. In this way, since everything except the fitting part is covered with a rubber-like elastic material, it is possible to provide a seal with excellent corrosion resistance. In addition, since it is protected by a rubber-like elastic body, corrosion resistance is not required for the material of the metal ring 1, and general materials such as carbon steel plates can be used, realizing a low-cost seal with excellent corrosion resistance. can. In such an oil seal, a metal ring 1 is fitted and fixed on the inner periphery of the housing 16 around the outer periphery. Then, the main lip 13 and the dust lip 14 on the inner circumferential side are slidably and sealed in contact with the shaft 17, and the gap between the shaft 17 and the inner circumference of the housing 16 is sealed. Here, the fitting part with the inner periphery of the housing 16 is the outer diameter part 15 with an exposed metal surface and the housing 1
Strong fitting force can be obtained by metal fitting with 6, and good fixing and sealing performance can be obtained against the effects of internal pressure, external pressure, etc. Furthermore, since the gasket part 10 and the rubber part 7 are provided at both ends of the metal ring 1, the airtightness of the outer periphery is also high. Furthermore, when installing the oil seal, the metal Fjll
In either case, when installing from the fluid side ○ end to be sealed to the inner periphery of the housing 16 or from the atmosphere side A end, the gasket part lO or the rubber part 7 must first be attached to the outer diameter part of the metal surface. It is fitted into the housing 16 prior to the housing 15. Therefore, the outer diameter portion 15 where the metal surfaces fit together is guided by the rubber-like elastic body, and the housing 1 is guided by the rubber-like elastic body.
6 and can be smoothly inserted into the inner periphery of the housing 16 to prevent galling or scratch grooves from occurring with the housing 16.

Figures 1 and 2 show a method of manufacturing the above-mentioned sealing device. That is, a mold 20 is used to vulcanize and mold a rubber material as a molding material, and the metal ring 1 is inserted and integrally molded with the rubber material. The mold 20 is a three-piece type that is divided into an upper mold 21, a middle mold 22, and a lower mold 23.
1. The middle mold 22 and the lower mold 23 are assembled by stacking each other on top of each other. A fitting hole 25 is provided in the center of the lower die 23, into which the core portion 24 is fitted in a liquid-tight manner. On the other hand, medium size 2
2 is also provided with a through hole 26 in the center that is approximately equal to the outer diameter of the oil seal, and this through hole 26 is connected to the core portion 24.
An annular recess 27 is formed between the lower mold 23, the middle mold 22, and the core part 24. When the upper mold 21 is closed, the annular recess 27 is closed to form an annular cavity 28.

The upper die 21 has an annular protrusion 29 inserted into the recess 27.
is formed protrudingly and forms the side surface of the U-shaped recessed seal on the side of the fluid to be sealed. A space for the main lip L3 shape is formed between the annular protrusion 29 and the core part 24, and a space for the outer periphery fitting part is formed between the annular protrusion 29 and the middle mold 22. The tapered portion 4 of the metal ring 1 is provided on the inner peripheral wall surface of the medium 22.
The engaging base portion 3o, which has a rectangular cross section and is engaged with, protrudes over the entire circumference, and the portion 3l that the tapered portion 4 abuts has a right-angled edge shape.

To manufacture an oil seal using the mold 20,
First, the mold is opened and the metal ring 1 is inserted into the annular recess 27 formed by the middle mold 22, the lower mold 23 and the core part 24 with the inward flange 5 facing downward. The outer diameter portion 15 of the metal ring 1 is guided by the inner circumferential wall surface of the medium mold 22 and moves downward, and is positioned at a position where the tapered portion 4 abuts the engagement seat portion 30. In this position, the inward flange portion 5 of the metal Ell must not come into contact with the bottom surface of the annular recess 29.

Next, the rubber dough is set, the mold is closed, and the mold is pressurized and heated.

Then, the fluidized rubber fabric 32 flows downward along the side surface of the core part 24 as shown by the arrow in the figure due to the oval pressure, and a part of the rubber fabric 32 that reaches the bottom of the annular recess 27 is
The rubber fabric 32 flows upward into the inner circumferential side of the metal ring 1, and the other rubber fabric 32 flows to the outside of the tapered part 4 of the metal ring 1.
At this time, the metal ring 1 is pressed downward by the pressure of the rubber fabric 32, and as shown in FIG. The contact surface pressure with the pedestal part 30 increases, and it is possible to prevent the rubber fabric 32 from wrapping around the outer circumferential side of the metal ring 1 as much as possible. In particular, in this embodiment, since the contact portion 31 is edge-shaped, the contact portion becomes a line contact, and overflow of the rubber fabric 32 can be easily stopped.

On the other hand, the tip side of the metal ring 1 is pressed outward by the molding pressure of the rubber dough 32 and the contact surface pressure with the inner circumferential wall surface of the medium mold 22 is high, so that the rubber dough 32 is prevented from wrapping around from the tip side. ing. The forming method may be compression molding as described above, or injection molding such as transfer molding or injection molding. Above upper mold 2
1 is provided with a hole 40 which functions as an air vent during compression molding and an injection hole during injection molding.

The mold used for this production is not a three-piece type as in this example, but a two-piece mold consisting of an upper mold 33 and a lower mold 34 as shown in FIG. 3 may be used. In this example, the joint surface between the lower die 34 and the upper die 33 is set to be near the center of the outer diameter portion 15 of the metal ring 1 when the metal ring 1 is inserted. An engaging pedestal portion 3o is provided on the inner circumferential wall surface of the lower die 34, with which the tapered portion 15 of the metal ring 1 engages. Other structures and functions are the same as those of the mold 20, so the same components are given the same reference numerals and their explanations will be omitted.

(Effects of the Invention) The present invention has the above-described configuration and operation, and includes providing a tapered portion on the outer periphery of the metal ring, and pressing the tapered portion against the inner wall surface of the mold by the pressure of the molding material using a wedge effect. As a result, the molding material can be completely sealed at this pressure-welded area, and it is possible to prevent the molding material from going around to the outer peripheral surface of the metal ring. Therefore, it is possible to obtain a metal surface on the outer periphery without performing post-processing, etc., and production efficiency can be improved.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a main part of a mold used in carrying out the manufacturing method of a sealing device according to an embodiment of the present invention, Fig. 2 is a partially enlarged view of Fig. FIG. 4 is a vertical cross-sectional view of a main part of another mold to which the manufacturing method of a sealing device of the present invention is applied; FIG. , FIG. 5 is a vertical cross-sectional view of the main part of the sealing device shown in FIG. 4, and FIG. 6 is a vertical cross-sectional view of the main part of the conventional sealing device. Explanation of symbols 3...Bending portion 5...Inward flange portion 8...Annular recessed portion 10...Gasket portion l3...Main lip l5...Outer diameter portion 17...Shaft 2l. ...Upper mold 23...Lower mold 26...Through hole 28...Cavity 3o...Engagement pedestal part 1...Metal ring 4...Tapered part 7...Rubber part 9... R part l1...Anti-corrosion rubber part l4...Dust lip 16...Housing 20...Mold 22...Middle mold 24...Core part 27...Annular recess 29...Annular convexity Part 31... Contact part 32... Rubber dough (molding material) 33... Upper mold 34... Lower mold Fig. 5 Fig. 6 lOO (ot to2

Claims (2)

[Claims] (1) A device that seals between a housing and a shaft that are assembled concentrically and movably relative to each other, and includes a metal ring whose outer peripheral metal surface is fitted to the inner circumference of the housing, and which makes sealing contact with the shaft. A sealing device integrally provided with a sealing member made of a rubber-like elastic body, characterized in that a tapered portion whose diameter gradually decreases toward the atmosphere side in the axial direction is provided at the atmosphere side end of the metal ring. Device. (2) A metal ring is inserted into the annular cavity provided inside the mold along its central axis, and a tapered part is provided at the tip of the metal ring in the insertion direction so that the outer diameter gradually decreases. , the tapered part is brought into fluid-tight contact with the inner wall facing the cavity of the mold, and the tapered part is bitten into the inner wall of the mold by the molding pressure of the molding material filled into the cavity using the wedge action of the tapered part. , a method for manufacturing a sealing device in which molding is performed by filling molding material while increasing contact surface pressure.