JPH0421572B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing an oil seal related to shaft seal technology.

[Conventional technology]

Conventionally, as a type of oil seal, as shown in FIG. 3, a metal reinforcing ring a having a substantially L-shaped cross section has an outer circumferential axial portion b and an inner circumferential free end of an inner radial portion c. It is known that seal members d and e made of rubber-like elastic material are vulcanized and bonded to the rubber-like elastic material. This type of oil seal is inserted into the inner periphery of the shaft hole of various rotating equipment, for example, and seals out various fluids by sliding the seal lip-shaped inner peripheral seal member e with the rotating shaft of the equipment. The inner circumference seal member e, which is in charge of the static seal part, and the outer circumference seal member d, which is in charge of the static seal part, are made of different materials suitable for their respective functions (for example, a fluorine material for the former e and a nitrile material for the latter d). Used selectively.

When manufacturing this type of oil seal using a mold, the reinforcing ring a is placed on the lower mold of the divided mold in the vertical direction, and each of the seal members d and e is placed on the inner and outer peripheries of the reinforcing ring a. The dough for molding is placed, the mold is clamped, and heated to vulcanize and bond each dough to the reinforcing ring a.
Generally, the lower surface of the upper mold is provided with an annular press-contact portion that presses against the reinforcing ring a during mold clamping, and is configured to prevent the doughs from mixing with each other.

[Problem that the invention seeks to solve]

However, according to this conventional manufacturing method,
The cavity shape and reinforcing ring of the mold in which the annular pressure welding part is integrally formed must be molded with high precision, and if the precision is poor, a gap will occur between the annular pressure welding part and the reinforcing ring when the mold is clamped. However, there are problems in that the dough may mix with each other through the gap, or conversely, the two may come into contact too quickly, resulting in incomplete mold clamping.

[Means for solving problems and their effects]

In view of the above-mentioned problems, the manufacturing method of the present invention engages and places the reinforcing ring of the oil seal on the lower die in the cavity of the molding die in a state before being compressed in the axial direction.
Seal member molding dough made of different materials is placed on the inner and outer peripheries of the reinforcing ring on the lower mold, and the mold is clamped while compressing the reinforcing ring in the axial direction to separate the inner and outer peripheries of the cavity. The dough is divided into parts and the dough filled in both parts is vulcanized and adhered to the reinforcing ring without mixing with each other, so that even if there is some variation in the molding accuracy of the inner wall of the mold cavity, the reinforcing ring can be fixed. It deforms into a shape that matches this and absorbs this accuracy error.

〔Example〕

An embodiment of the present invention will be described below, focusing on the configuration of a mold used for carrying out the embodiment.

In FIGS. 1 and 2, the molds indicated by the reference numeral 1 as a whole are an outer upper mold 2, an inner upper mold 3, and an outer mold 4.
and the lower mold 5 are concentrically combined, and the first
As shown in the figure, a ring-shaped cavity 6 is formed at the center of the joint of these split molds, and on the upper surface of the lower mold 5, which forms the lower surface of the cavity 6,
A reinforcing ring support projection 7 having a flat radial surface 8 and an axial surface 9 is integrally provided.

As shown in FIG. 1, this molding die 1 includes a reinforcing ring f having a substantially Z-shaped cross section and having axial portions h and i extending in opposite directions at both ends of a radial portion g.
An oil seal is formed on the outer periphery and inner periphery of the mold 1 by vulcanizing and adhering sealing member molding doughs d' and e' made of different materials.The procedure and operation of the mold 1 are as follows.

The mold 1 is opened, and the reinforcing ring f is engaged and placed on the reinforcing ring support protrusion 7, and the supporting protrusion 7
On the outer mold 4 and the lower mold 5 on the inner and outer peripheries, annular sealing member forming doughs d' and e' are placed, respectively (FIG. 2). The reinforcing ring f is approximately Z as described above.
It is not compressed in the axial direction to a letter-shaped cross section, but is preformed in such a way that the radial portion g is oblique.

When mold closing is started while operating a heating mechanism (not shown), before closing is completed, the lower surface of the outer upper mold 2, which forms the upper surface of the cavity 6, comes into contact with the upper end of the axial portion i of the reinforcing ring f, and then, The mold is closed while compressing the reinforcing ring f, and when the mold is closed, the cavity 6 is divided into an inner peripheral portion and an outer peripheral portion with the reinforcing ring f as a boundary (FIG. 1). The sealing member forming doughs d' and e flow by heating and pressurizing and fill the cavity 6.

After waiting for the adhesion and crosslinking of both fabrics d' and e' to the reinforcing ring f and curing, the mold is opened and the molded product is released.

〔Effect of the invention〕

As explained above, the method for manufacturing an oil seal of the present invention includes mold-clamping the reinforcing ring while compressing it in manufacturing an oil seal in which seal member forming dough is vulcanized and bonded to each of the inner and outer peripheries of a reinforcing ring. Since the cavity is completely divided into an inner circumferential portion and an outer circumferential portion, it is possible to prevent the dough from mixing with each other, and the reinforcing ring is processed and molded into the final product shape at the same time as mold clamping is completed. It has the characteristics of being able to manufacture oil seal products in large quantities with excellent specification accuracy.

[Brief explanation of drawings]

1 and 2 are half-cut sectional views showing the operating state of a mold used in the manufacturing method according to an embodiment of the present invention, and FIG. 3 is a half-cut sectional view of an oil seal. 1...Molding mold, 2...Outer upper mold, 3...Inner upper mold, 4...Outer mold, 5...Lower mold, 6...Cavity, 7...Reinforcement ring support protrusion, f...Reinforcement ring , d′,
e′...Dough for forming sealing members.

Claims (1)

[Claims] 1. A reinforcing ring of an oil seal is engaged and placed on the lower mold in the cavity of the mold in a state before being compressed in the axial direction, and different materials are placed on the inner and outer peripheries of the reinforcing ring on the lower mold. A dough for forming a seal member is placed, and the mold is clamped while compressing the reinforcing ring in the axial direction to divide the cavity into an inner circumferential portion and an outer circumferential portion, and the dough filling both portions is mixed with each other. A method for manufacturing an oil seal, characterized in that the oil seal is vulcanized and bonded to the reinforcing ring without causing any damage.