JPH0578711B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a sealing device used to seal between two concentrically assembled members, and in particular to an oil sealing device having a resin sealing lip with a threaded groove on the sealing surface. The present invention relates to a method for manufacturing a seal.

(Prior Art) As a conventional method for manufacturing this type of oil seal, there is a method shown in FIGS. 6 to 8, for example (see Japanese Patent Publication No. 60-56618). That is, in FIG. 6, reference numeral 100 indicates an oil seal, and the outer diameter side of a resin seal ring 101 is assembled to an annular support member 102. The inner diameter side of the seal ring 101 is bent toward the sealed fluid side to form a seal lip 103, and the sealing surface of the seal lip 103 is provided with a thread groove 104a. To manufacture such a sealing device 100, first, as shown in FIG.
A thread is cut from the inner diameter side of the end face of the resin material 105 by a thread cutting means 104, and then the end portion of the resin material 105 is cut out to a predetermined width by a cutting means 106 to form a thin plate-like seal ring 101. Thereafter, as shown in FIG. 8, the seal ring 10 is formed by press working.
The inner diameter side of 1 was bent at a predetermined angle and assembled to the support member 102.

(Problems to be Solved by the Invention) However, in the case of such a conventional example, threading, cutting, and bending must be performed in separate processes to form the seal ring 101, resulting in a problem of poor production efficiency. It was hot. In particular, the bending process is performed using a press machine after the seal ring 101 is cut out, which requires equipment separate from the equipment for thread groove processing and cutting, resulting in the problem of an increase in the size of the production equipment. .

In addition, since the seal ring 101 is bent after being cut out using a press die or the like, it is necessary to center the bent portion with high precision during bending, and the degree of bending of the bent portion must be controlled with high accuracy. When changing, the press mold had to be changed, making processing difficult.

The present invention has been made to solve the problems of the prior art described above, and its purpose is to improve production efficiency by making it possible to perform seal ring cutting, threading, and bending processes in one process. The object of the present invention is to provide a method for manufacturing an oil seal that can be improved.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, the end of a resin material molded into a cylindrical shape is cut into rounds from the inner diameter side to the outer diameter side at a predetermined width. At the same time, forming a thread groove on the cut surface of the cut-out piece in the middle of cutting out, and bending the inner diameter side of the cut-out piece into a cylindrical shape to form a seal ring, and assembling the outer diameter side of the seal ring to a support member. It consists of a step of attaching.

(Example) The present invention will be explained below based on the illustrated example. FIG. 2 shows an oil seal manufactured by an oil seal manufacturing method according to an embodiment of the present invention. That is, 1 is a seal ring made of resin, and the outer diameter side of the seal ring 1 is assembled to an annular support member 2. On the other hand, the inner diameter side of the seal ring 1 is bent toward the sealing fluid side to form a seal lip 1a, and a thread groove 3 is cut on the seal surface of the seal lip 1a by a predetermined width from the tip of the seal lip 1a. The support member 2 consists of an outer cylinder 21 that is fitted into the housing 4 and an inner cylinder 22 that is fitted to the inner periphery of the outer cylinder 21, and includes a flange extending radially inward on the side edge of the outer cylinder 21 to which rubber is baked. The outer diameter side end 1b of the seal ring 1 is sandwiched between the flange 21a and the flange 22a extending radially inward on the side edge of the inner cylinder 22, and the side edge 21b of the outer cylinder 21 on the sealed fluid side is caulked. It is assembled by Further, 5 is a sleeve, which is attached as necessary and fitted onto the shaft 6 to prevent wear on the surface of the shaft 6. Note that 2a is a dust strip.

1 and 3 show a method of manufacturing the oil seal. In the figure, 10 is a resin material molded into a cylindrical shape. The inner diameter and outer diameter of this resin material 10 are pre-molded to predetermined dimensions. Similar to the conventional example, the resin material 10 is rotatably mounted on a lathe or the like with its central axis serving as a rotation axis. In this embodiment, PTFE resin is used as the resin material 10, which has excellent abrasion resistance, weather resistance, oil resistance, chemical resistance, and the like. Motomo
Not limited to PTFE, but also FEP (tetrafluoroethylene hexafluoropropylene copolymer), PFA (tetrafluoroethylene perfluoroalkoxide),
Various resins such as EPFE (ethylene tetrafluoroethylene copolymer), polyetheretherketone, and high-molecular polyethylene may be used, and these resins may also be used with short glass fibers, short carbon fibers, metal fibers, short ceramic fibers, whiskers, etc. Various materials can be applied, such as fillers such as graphite powder, metal powder, glass powder, ceramic powder, resin powder, etc., used alone or in combination of two or more to provide wear resistance and low friction properties. be.

Reference numeral 11 denotes a tool used to carry out the present invention, and the tool is supported by a support means (not shown) and its movement is controlled. As shown in FIG. 4, this tool 11 includes a cut-off part 12 having a knife-like tip, a threaded part 13 protruding in the middle of the cut-off part 12, and a cut-off part 12 cut out by the cut-off part 12. A guide portion 15 for bending the piece 14 into a predetermined shape is provided. The cut-off portion 12 extends perpendicularly to the central axis of the resin material 10, and is disposed on the inner circumferential side of the resin material 10, with the tip of the cut-off portion 12 facing toward the outer circumferential side of the resin material 10. It is being The threaded portion 13 is provided protruding from the side surface of the cut-off portion 12 opposite to the end surface of the resin material 10.
It is provided at a position a predetermined distance L from the tip of the tip. The threaded portion 13 is shaped to match the cross-sectional shape of the threaded groove 3. That is, by appropriately selecting the protrusion width, the depth of the thread groove 3 can be formed to a desired depth. Further, the guide portion 15 is formed into a curved surface corresponding to the degree of bending of the seal ring 1, and the threaded portion 1
3, the resin material 10 is gradually inclined in the direction of the central axis of the resin material 10 to form a curved shape.

By using the tool 11 described above, the seal ring 1 is formed in the following manner. First, tool 1
1 is moved to the inner peripheral side of the resin material 10 by a support means (not shown), and the point of the cut-off portion 12 is set at a position recessed by a predetermined width from the end surface of the resin material 10. Next, while rotating the resin material 10 and the tool 11 relative to each other, the cut-off portion 12 is cut off from the resin material 1.
0 from the inner diameter side toward the outer diameter side. Then, the end portion of the resin material 10 is cut out with a predetermined width by the cut-off portion 12, and when the thread cut portion 13 moves to the inner diameter end position of the resin material 10, the cut surface of the cut-out piece 14 of the resin material 10 is cut out. 14
A thread groove 3 is spirally carved from the inner diameter end of the hole a. That is, the cutout piece 14 is pressed against the threaded portion 13 by its elastic force, and the cut surface 14a bites into the threaded portion 13. A desired pitch of the thread groove 3 can be selected by adjusting the moving speed of the tool 11 and the rotational speed of the resin material 10. When the tool 11 further moves outward in the radial direction, the cutout piece 14 in which the thread groove 3 is carved
The inner diameter end portion of the tube is expanded in diameter along the guide portion 15 and bent into a cylindrical shape. Bending portion 1 of seal ring 1
The shape of the guide portion 4b can be arbitrarily set by changing the position and shape of the curved surface of the guide portion 15. When the tip of the cut-off portion 12 of the tool 11 reaches the outer diameter end of the resin material 10, the cut-out piece 14 is cut off and the seal ring 1 as shown in FIG. 5 is formed. When the seal ring 1 is cut off, the threaded portion 13 no longer comes into contact with the cut-out piece 14, so the width of the thread groove 3 is the same as the threaded portion when the tip of the cut-off portion 12 reaches the outer diameter end of the seal ring 1. It will be formed up to the 13th position. In this embodiment, when the cutout piece 14 is in a free state, the thread groove 3 is machined by the elastic force of the cutout piece 14.
3 is inserted into the cutout piece 14,
A guide member that presses the cutout piece 14 toward the end surface of the resin material 10 may be used. In this way, thread groove 3
Since the width of the forming area can be determined by the position of the threaded part 13 from the tip of the cut-off part 12,
It becomes possible to easily set the width of the thread groove 3 forming area.

Therefore, when such a tool 11 is used, cutting, thread groove processing, and even bending can be performed simply by moving the tool 11 from the inner diameter side to the outer diameter side of the resin material 10, and the seal ring 1 can be formed. becomes extremely easy. Of course, it is not necessary to use one tool to perform the thread groove processing and bending processing simultaneously during cutting, using dedicated tools for each.

Next, the seal ring 1 formed in this way is assembled to the support member 2. In the assembly, the seal ring 1 and the inner cylinder 22 are sequentially assembled into the outer cylinder 21 of the support member 2, and the sealing fluid side of the outer cylinder 21 is assembled into the outer cylinder 21 of the support member 2. This is done by caulking the side edges 21b. Various methods such as roller caulking can be applied to this caulking. Once the seal ring 1 is assembled to the support member 2, the final product of the oil seal is completed. Further, a sleeve 5 is attached to the inner periphery of the seal lip 1a as required.

(Effects of the Invention) The present invention has the structure and operation described above, and the cutting, threading, and bending of the seal ring, which were conventionally separate processes, are performed in one process, so production efficiency is greatly improved. At the same time, it becomes extremely easy to mold the seal ring without increasing the size of production equipment. Furthermore, since the bending process is performed at the same time as cutting out the seal ring, there is no need to center the bent part, and various effects such as ease of shaping can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing a method for manufacturing an oil seal according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of essential parts of an oil seal manufactured by the method shown in FIG. The figures are a schematic perspective view of the vicinity of the resin material shown in Fig. 1, Fig. 4 is a schematic perspective view of the tool shown in Fig. 1, and Fig. 5 is a schematic perspective view of the vicinity of the resin material shown in Fig. 1.
The figure is a schematic perspective view of a seal ring formed by the method shown in Figure 1, Figure 6 is a vertical sectional view of the main part of a conventional oil seal, and Figure 7 is a conventional seal ring cut out and thread grooved. FIG. 8 is a longitudinal cross-sectional view of a main part of a press die showing a state of bending and assembly of a conventional seal ring. Explanation of symbols, 1... Seal ring, 2... Support member, 10... Resin material, 11... Tool, 12...
... cut-off part, 13 ... thread cut part, 14 ... cut-out piece, 14a ... cut surface, 15 ... guide part.

Claims (1)

[Claims] 1 The end of a resin material formed into a cylindrical shape is cut into rings with a predetermined width from the inner diameter side to the outer diameter side, and at the same time, a thread groove is formed on the cut surface of the cut piece in the middle of cutting, and the inner diameter side of the cut piece is formed. A method for manufacturing an oil seal, comprising the steps of: bending a seal ring into a cylindrical shape to form a seal ring; and assembling the outer diameter side of the seal ring to a support member.