JPH0610508B2 - Method for manufacturing sealing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sealing device used for sealing between concentric two rotating members, and more particularly to a resin sealing lip having a thread groove on a sealing surface. The present invention relates to a method of manufacturing a sealing device having the same.

(Prior Art) Conventionally, as a method of manufacturing a sealing device of this type, there is, for example, one shown in FIGS. 9 to 11 (US Pat.
2,255,155). That is, reference numeral 100 denotes a sealing device, and an 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 to the sealed fluid side to form a seal lip 103, and a thread groove 104a is formed on the sealing surface of the seal lip 103. In order to manufacture such a sealing device 100, first, as shown in FIG. 10, a thread is formed on a single surface of a resin cylindrical body 105 such as PTFE having an inner diameter and an outer diameter formed into predetermined dimensions by a thread cutting means 104 from the inner diameter side. After cutting, the end portion of the resin cylindrical body 105 is cut with a predetermined width by the cutting means 106 to form the thin plate-shaped seal ring 101. After that, as shown in FIG. 11, the inner diameter side of the seal ring 101 is bent at a predetermined angle by pressing to form the seal lip 103 and the seal ring 101 is assembled to the support member 102. The lower ring 107 is used for bending the seal ring 101.
A taper surface 107a for molding the seal lip 103 is provided on the above, and the upper lip 108 and the lower die 107 are used to compress in the vertical direction.

(Problems to be Solved by the Invention) However, in the case of such a conventional example, there is a problem that a bending step is required after the thread groove 104a is provided, and there are many manufacturing steps, resulting in poor production efficiency.

Further, since the seal ring 101 is bent by press working after providing the thread groove 104a, the shape of the thread groove 104a can be changed by the extension of the seal ring 101 accompanying the bending work
Alternatively, there is a problem in that the predetermined screw groove 104a cannot be obtained due to a change in depth. Further, during compression molding by pressing, the thread groove 104a of the seal ring 101 is
Of the thread groove 104 because the taper surface 107a of the
There is a problem that a may be rubbed and crushed, the screw pump function may be impaired, and desired sealing performance may not be obtained.

The present invention has been made in order to solve the above-mentioned problems of the prior art. The object of the present invention is to form a predetermined thread groove by performing bending while cutting and then providing a thread groove. It is an object of the present invention to provide a method of manufacturing a sealing device that can be manufactured and can shorten the manufacturing process.

(Means for Solving Problems) In the method for manufacturing a sealing device according to the present invention in order to achieve the above object, a resin cylindrical body is rotated with a central axis of the resin cylindrical body as a rotation axis, and The end portion of the resin cylindrical body is cut into a plate shape from the inner diameter side to the outer diameter side by cutting means, and at the same time as the cutting, the cutting means bends the inner diameter side of the cutting piece into a substantially L-shaped cross section, and thereafter, While pressing the outer peripheral surface of the bent portion with the outer diameter holding ring, a thread groove is formed on the inner peripheral surface by the thread cutting means, and then the cutting piece is completely cut off by the cutting means to form a seal ring. It is configured by assembling the outer diameter side of the with a support member.

(Example) Below, this invention is demonstrated based on the Example shown in figure. 1 to 8 showing the method of manufacturing the sealing device according to the embodiment of the present invention, the same sealing device as the conventional example shown in FIG. 9 is manufactured also in this embodiment. In FIG. 1, reference numeral 1 denotes a resin cylindrical body made of PTFE (tetrafluoroethylene resin), which is rotatably attached to a lathe or the like with its central axis as a rotation axis. The inner diameter and the outer diameter of the resin cylindrical body 1 are preliminarily molded into predetermined dimensions. Around the resin cylinder 1, there are a cutting means A for cutting the end of the resin cylinder 1 into a thin plate shape, and a bending means B for bending the cutting piece 2 cut by the cutting means A into a substantially L-shaped cross section. It is arranged. As shown in FIG. 2, the cutting means A uses a cutting tool arranged along the central axis of the resin cylinder 1, and the cutting edge 3 is bent in a direction perpendicular to the central axis of the resin cylinder 1. The end portion of the resin cylindrical body 1 is cut out in a thin plate shape from the inner diameter side to the outer diameter side. That is, the cutting means A is movable in the central axis direction of the resin cylindrical body 1 and in the direction perpendicular to the central axis, and is moved in the central axis direction by a predetermined thickness from the end surface of the resin cylindrical body 1 by a control mechanism (not shown). The thin plate is cut out by moving from the inner diameter side of the resin cylindrical body 1 to the outer diameter direction.

On the other hand, the bending means B is arranged along the radial direction of the resin cylindrical body 1 as shown in FIG. 3, and a pair of inner bending rolls 4 for pressing the cutting piece 2 cut by the cutting means A.
And the outer bending roll 5, and in this embodiment, they are symmetrically arranged at two places. Both bending rolls 4,
The central axis of 5 is arranged in parallel with the central axis of the resin cylinder 1, and is adapted to rotate in the direction opposite to the moving direction of the cutting piece. The outer peripheral surface of the tip end portion of the inner bending roll 4 is a taper portion 4a that is sharply inclined outward in the radial direction toward the end portion, and the taper portion 4a is arranged to face the end surface of the outer bending roll 5. That is, the inner bending roll 4 moves outward in the radial direction of the resin cylinder 1 in conjunction with the cutting means A, and the tapered portion 4a bites into the gap between the cutting pieces 2 on the inner diameter side cut by the cutting means A. The cutting piece 2 is scooped along the tapered portion 4a. Further, the outer bending roll 5 is moved to the inner bending roll 4 side, and the cutting piece 2 is compressed by each of the bending rolls 4 and 5 to be expanded and bent into a substantially L-shaped section so as to project in parallel with the central axis. The bent portion 6 is formed. When the cutting piece 2 is compressed by the pair of bending rolls 4 and 5 as described above, the contact between each bending roll 4 and 5 and the cutting piece 2 becomes a line contact, so that the compressive load can be increased and the workability is improved. improves.

The cutting by the cutting means A and the bending step by the bending means B are performed at the same time, and the cutting is stopped in the middle without being completely cut as shown in FIG.

Next, as shown in FIG. 4 and FIG.
Thus, the thread groove 7 is formed on the inner peripheral surface 6a of the bent portion 6.
As the thread cutting means C, there is used a thread cutting tool which extends along the central axis of the resin cylindrical body 1 and whose tip 8 is directed outward in the radial direction. In this thread cutting step, the outer peripheral side of the bent portion 6 of the cutting piece 2 is held by the outer diameter holding ring 9
Held by. The outer diameter retaining ring 9 is a cylindrical body having a stepped shape on the inner diameter side, and the inner peripheral surface is provided coaxially with the large diameter hole portion 9a fitted to the outer periphery of the end of the resin cylindrical body 1 and the large diameter hole portion 9a. And a small diameter hole portion 9b
The inner peripheral surface is brought into contact with the outer peripheral surface of the bent portion 6. At this time, the inner diameter and outer diameter bending rolls 4 and 5 are separated from the resin cylinder 1, but the inner diameter bending roll 4 may hold the inner peripheral surface of the bending portion 6.

In the thread cutting, the position of the cutting edge of the tip of the thread cutting means C is positioned at a position where it bites into the inner peripheral surface of the bent portion 6 by a predetermined depth, and the cutting means A is moved at a constant width in the central axis direction of the resin cylinder 1 by a predetermined width. It is done by moving to. As it is moved, the rotation of the resin cylinder 1 and the movement of the thread cutting means C are combined to form a single thread groove 7 in a spiral shape. After the thread groove 7 is formed by a predetermined width, the thread cutting means C is bent. The threading is completed by separating from 6. The depth of the thread groove 7 can be adjusted by the biting amount of the thread cutting means C, and the shape of the thread groove 7 can be set to any desired shape by the shape of the cutting edge of the thread cutting means C. If a plurality of thread cutting means C are used, a plurality of thread grooves 7 can be formed.

FIG. 6 shows another mode of the thread cutting means C,
A pressing member 10 that presses the springback of the bent portion 6 of the cutting piece 2 is provided. The pressing member 10 has a disk-shaped portion 10a whose outer peripheral surface abuts the bent portion 6, and a shaft portion 10b which is rotatably mounted in a mounting hole 11 provided at the tip of the cutting means A.
And the contact portion of the disc-shaped portion 10a with the bent portion 6 rolls. The outer peripheral surface of the disk-shaped portion 10a is located inside the cutting edge position of the cutting means A.

After the thread cutting, the outer diameter retaining ring 9 and the thread cutting means C are separated from the resin cylindrical body 1, and the cutting means A is again moved outward in the radial direction of the resin cylindrical body 1 as shown in FIGS. 7 and 8. Completely cut off to form the seal ring 101. The seal ring 101 has a taper shape in which the bent portion 6 formed in the bending process has a tip portion that is reduced in diameter by springback and gradually reduced toward the tip.

The cut-off seal ring 101 is assembled to the support member 102 on the outer diameter side as shown in FIG. 9, and the sealing device 100 having the bent portion 6 as the seal lip 103 is completed. That is, the seal ring 101 is fitted from the end of the outer cylinder 102a forming the support member 102 on the side of the sealed fluid, and the inner cylinder 102b is further fitted to the outer diameter side end of the seal ring 101 to the outer cylinder 102a and the inner cylinder 102b. The atmosphere side flanges 102c and 102d are pressed against each other, and the outer fluid side edge of the outer cylinder 102a is caulked inward in the radial direction to assemble.

In the sealing device manufactured by such a method, the thread groove 7 can be formed into a desired shape and depth by the thread cutting means C, so that the thread groove 7 having a sharp edge can be realized. By making the thread groove 7 a sharp edge,
The sealing fluid is well cut off, the screw pump function of the screw groove 7 is high, and a sealing device with high sealing performance can be obtained.

As the material of the resin cylinder 1, in addition to PTFE, FEP (tetrafluoroethylene hexafluoropropylene copolymer), PFA (tetrafluoroethylene / perfluoroalcooxide), EPFE (ethylene tetrafluoroethylene) Various resins such as copolymers), polyether ether ketone, high molecular weight polyethylene, etc. may be used, and glass short fibers, carbon short fibers, metal fibers, ceramic short fibers, whiskers, graphite powder, metal powder, Filler such as glass powder, ceramic powder, resin powder, etc. alone or 2
A mixture of more than one type that has been given wear resistance and low friction, etc.
Various materials can be applied.

(Effects of the Invention) The present invention has the above-described configuration and action. Since the cutting piece is bent into a substantially L shape by the bending means at the same time as cutting, it is necessary to bend after forming the seal ring as in the conventional case. Can be eliminated and the manufacturing process can be shortened. Also, after bending the cutting piece, we made thread groove processing, so
The depth and shape of the thread groove does not change due to the expansion and deformation of the seal ring due to bending as in the past, and it is possible to machine the thread groove with the desired depth and shape.
A sealing device having excellent sealing performance can be manufactured.

[Brief description of drawings]

FIG. 1 is a schematic perspective view in the vicinity of a resin cylinder showing a cutting and bending process of a method for manufacturing a sealing device according to the present invention, FIG. 2 is a schematic sectional view showing a cutting state of FIG. 1, and FIG. 1 is a schematic sectional view showing a bending state, FIG. 4 is a schematic sectional view in the vicinity of a resin cylinder showing a thread cutting step of the present invention, FIG. 5 is a schematic perspective view of FIG. 4, and FIG. FIG. 7 is a schematic cross-sectional view showing another aspect of the thread cutting means of the figure, FIG. 7 is a schematic cross-sectional view showing a cut-off state of the resin cylindrical body, and FIG. 8 is a schematic perspective view of the cut-off seal ring of FIG. FIG. 9 is a longitudinal sectional view of a main part of a conventional sealing device, FIG. 10 is a schematic perspective view showing a seal ring molding state of the conventional sealing device, and FIG. 11 shows a conventional seal ring bending process and an assembled state. It is a longitudinal cross-sectional view of a main part of a press die. DESCRIPTION OF SYMBOLS 1 ... Resin cylindrical body, 2 ... Cutting piece 4, 5 ... Inner / outer bending roll, 6 ... Bending portion 7 ... Thread groove, 9 ... Outer diameter retaining ring A ... Cutting means, B ... Bending means C ... Thread cutting means

Claims (1)

[Claims] 1. A resin cylindrical body is rotated about a central axis of the resin cylindrical body as a rotation axis, and an end portion of the resin cylindrical body is cut into a plate shape by a cutting means from an inner diameter side to an outer diameter side partway. ,
Simultaneously with the cutting, the inner diameter side of the cutting piece is bent into a substantially L-shaped section by the bending means, and thereafter, the outer peripheral surface of the bent portion is pressed by the outer diameter retaining ring, and a thread groove is formed on the inner peripheral surface by the thread cutting means. Then, the cutting piece is completely cut off by the cutting means to form a seal ring, and the outer diameter side of the seal ring is assembled to a support member.