JPH0610509B2 - Method for manufacturing sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention has a sealing device used for sealing between two concentrically assembled two rotating members, in particular, a resin sealing lip provided with a thread groove on the sealing surface. The present invention relates to a method for manufacturing a sealing device.

(Prior Art) Conventionally, as a method of manufacturing a sealing device of this type, there is, for example, one shown in FIGS.
2,255,155). That is, 10 in FIG.
0 indicates a sealing device, and a resin seal ring 1
The outer diameter side of 01 is assembled to the 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. To manufacture such a sealing device 100, as shown in FIG. 11, first, as shown in FIG.
The thread cutting means 1 is provided on the end surface of the resin cylinder 105 such as TFE.
After the thread is cut from the inner diameter side by 04, the end portion of the resin cylindrical body 105 is cut out by the cutting means 106 with a predetermined width to form the thin plate-shaped seal ring 101. Then first
As shown in FIG. 2, the seal ring 101 is formed by pressing.
This is done by bending the inner diameter side of the to a predetermined angle to form the seal lip 103 and assembling the seal ring 101 to the support member 102. In the bending process of the seal ring 101, the lower die 107 is provided with a taper surface 107a for forming the seal lip 103, and the upper die 108 and the lower die 107 are vertically compressed to form the seal ring 101.

(Problems to be Solved by the Invention) However, in the case of such a conventional example, since the seal ring 101 is bent by press working after the thread groove 104a is provided, the thread groove is extended due to the elongation of the seal ring 101 accompanying the bending work. There is a problem in that the predetermined thread groove 104a cannot be obtained due to a change in the shape or depth of 104a. Furthermore, since the thread groove 104a of the seal ring 101 is pressed against the taper surface 107a of the lower die 107 during compression molding by the press, the thread groove 104a may be rubbed and crushed, and the screw pump function is impaired and desired sealing performance is obtained. There was a problem that I could not get.

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 order to achieve the above object, in a method for manufacturing a sealing device according to the present invention, a resin cylindrical body is rotated with a central axis of the resin cylindrical body as a rotation axis, and Cutting and bending in which the end of the resin cylindrical body is cut into a plate shape from the inner diameter side to the outer diameter side partway by the cutting means, and at the same time as the cutting, the inner diameter side of the cutting piece is bent into a substantially L-shaped cross section by the bending means. And a groove processing step of engraving a screw groove on the outer peripheral surface by a groove cutting means while pressing the inner peripheral surface of the bent portion with an inner diameter holding jig, and an outer diameter of the end portion of the resin cylindrical body by the cutting means. Having a cutting step of completely cutting off to the side to form a seal ring, a reversing step of reversing the bent portion of the seal ring, and an assembling step of assembling the outer diameter side of the seal ring with a support member. It consists of.

(Example) Below, this invention is demonstrated based on the Example shown in figure. 1 to 9 showing the method for manufacturing the sealing device according to the embodiment of the present invention, the same sealing device as the conventional example shown in FIG. 10 is manufactured also in this embodiment. FIG. 1 shows the cutting and bending process of the present invention. That is, 1 is 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 the cutting means A, a cutting tool arranged along the central axis of the resin cylindrical body 1 is used as shown in FIG. 2, and the cutting edge 3 is bent in a direction perpendicular to the central axis of the resin cylindrical body 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 cylinder 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 and outer bending rollers that press the cutting pieces 2 cut by the cutting means A are pressed. In this embodiment, the rolls 5 and 5 are arranged symmetrically at two positions. The central axes of the bending rolls 4 and 5 are arranged parallel to the central axis of the resin cylindrical body 1, and rotate in the opposite direction to the moving direction of the cutting piece 2. The inner bending roll 4 moves in the radial direction outward of the resin cylindrical body 1 in conjunction with the cutting means A. On the other hand, the outer bending roll 5 is moved to the inner bending roll 4 side, and the cutting piece 2 is sandwiched by the bending rolls 4 and 5 so as to be extended and projected in parallel with the central axis line while having an approximately L-shaped cross section. Bend and bend part 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 compression load can be increased and The property is improved.

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, FIG. 4 and FIG. 5 show the groove processing step. In this step, the groove groove C is used to engrave the thread groove 7 on the inner peripheral surface 6a of the bent portion 6. As the thread cutting means C, there is used a groove cutting tool which extends along the central axis of the resin cylindrical body 1 and whose tip 8 is directed radially outward. In this groove machining step, the inner peripheral surface of the bent portion 6 of the cutting piece 2 is held by the inner diameter holding jig 9. The inner diameter holding jig 9 has an arcuate holding surface that substantially follows the inner peripheral surface of the substantially bent portion 6, is arranged so as to face the thread cutting means C, and the holding surface is in sliding contact with the inner peripheral surface of the bent portion 6. To be done. At this time, the inner diameter and outer diameter bending rolls 4 and 5 are separated from the resin cylindrical body 1, but the inner diameter bending roll 4 may hold the inner peripheral surface of the bending portion 6.

Grooving is performed by bending the position of the cutting edge of the tip of the thread cutting means C into the bending portion 6
This is done by positioning the groove cutting means C at a position where it digs in a predetermined depth from the inner peripheral surface, and moving the groove cutting means C at a constant width in the central axis direction of the resin cylindrical body 1 by a predetermined width. As the resin cylindrical body 1 is moved and the groove cutting means C is moved together, a single thread groove 7 is engraved in a spiral shape. After engraving the thread groove 7 by a predetermined width, the groove cutting means C is moved. Grooving is completed by moving away from the bent portion 6. The depth of the thread groove 7 is the groove cutting means C.
The shape of the screw groove 7 can be set to any desired shape by the shape of the cutting edge of the groove cutting means C, while adjusting the amount of biting. If a plurality of groove cutting means C are used, a plurality of thread grooves 7 can be formed.

After the groove processing, the inner diameter holding jig 9 and the groove cutting means C are separated from the resin cylindrical body 1. 6 and 7 show the cutting process. In this step, the cutting means A is again moved outward in the radial direction of the resin cylindrical body 1 and completely cut off to form the seal ring 101.

Next, FIGS. 6 to 8 show the reversing step.
In this step, the bent portion 6 is inverted. Ie 10
Indicates a check, and the outer diameter side of the seal ring 101 is checked. 1 in FIGS. 6 and 7
Reference numeral 1 denotes a first reversing jig, which is a seal ring 101.
The arm 11a extending in the radial direction has a rod-shaped roll 11b attached to the tip thereof. Roll 11b
The base end of the arm is rotatably attached to the arm 11a, and the end of the arm 11a is bent toward the seal ring 101. Further, a flexible protective cover 11c made of rubber or the like is attached to the outer circumference of the roll 11b, and the seal ring 101
While rotating, the bending portion 6 is pressed in the reversing direction by the roll 11b to be reversed over the entire circumference. The roll 11b is pressed against the thread groove 7 portion of the bent portion 6, but the roll 11b rolls along the surface of the bent portion 6, so that the thread groove 7 is not crushed by rubbing. Roll 11
Since the protective cover 11c is attached to b, the roll 11
There is no risk of the screw groove 7 being crushed by the pressing force of b.

FIG. 8 shows a second reversing jig 12, which can adjust the tilt angle of the reversed bent portion 6 to a predetermined angle. The second reversing jig 12 is a rod-shaped roll 12a rotatable about a central axis, and a protective cover 12b similar to that of the first reversing jig 11 is attached to the tip end portion thereof.
After turning over, the seal ring 101 is removed from the chuck 10.

Next, the removed seal ring 101 is assembled to the support member 102 on the outer diameter side as shown in FIG. 10 (assembling step), and the sealing device having the inverted bent portion 6 as the seal lip 103 is completed. That is, in the assembling, the seal ring 101 is fitted from the end of the outer cylinder 102a constituting the support member 102 on the side of the sealed fluid, and the inner cylinder 102b is further fitted so that the outer diameter side end of the seal ring 101 is fitted to the outer cylinder 102.
a and the atmosphere side flanges 102c, 10 of the inner cylinder 102b
The pressure is applied by 2d, and the end of the outer cylinder 102a on the side of the sealed fluid is caulked inward in the radial direction for assembly.

The steps of reversing and assembling may be reversed after assembling the seal ring 101, and the order is not limited.

In the sealing device manufactured by such a method, since the thread groove 7 can be formed into a desired shape and depth by the groove cutting means C, the thread groove 7 having a sharp edge can be realized. By forming the thread groove 7 with a sharp edge, the sealing fluid can be cut off well, the thread pump function of the thread 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 tetrafluoride) Various resins such as ethylene copolymer), polyether ether ketone, and high molecular weight polyethylene may be used, and glass short fibers, carbon short fibers, metal fibers, ceramic short fibers, whiskers, graphite powder, metal Powder, 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 and then thread groove processing is performed, the thread groove is formed by stretching or deformation of the seal ring by bending as in the conventional case. The depth and shape of the groove can be prevented from changing, a thread groove having a desired depth and shape can be processed, and 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 cylindrical body showing a cutting and bending step of a method for manufacturing a sealing device according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a cutting state of FIG. Three
1 is a schematic sectional view showing a bending state of FIG. 1, FIG. 4 is a schematic sectional view in the vicinity of a resin cylinder showing a groove processing step of this embodiment, FIG. 5 is a schematic perspective view of FIG. FIG. 6 is a schematic cross-sectional view showing a state where the resin cylindrical body according to the cutting process of the present embodiment is cut off, FIGS. 7 to 9 show the reversing process of the present embodiment, and FIG. FIG. 8 is a schematic sectional view showing an inverted state by an inversion jig, FIG. 8 is a schematic perspective view of FIG. 7, FIG. 9 is a schematic sectional view showing an inverted state by a second inversion jig, and FIG. 10 is a conventional sealing device. Fig. 11 is a schematic perspective view showing a seal ring molding state of a conventional sealing device, and Fig. 12 is a press type main section longitudinal view showing a conventional seal ring bending process and an assembled state. Is. 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: Grooving means

Claims (1)

[Claims] 1. A resin cylindrical body is rotated about a central axis of the resin cylindrical body as a rotating shaft, and an end portion of the resin cylindrical body is cut by a cutting means from an inner diameter side to an outer diameter side to a plate shape partway. ,
Simultaneously with the cutting, a cutting and bending step of bending the inner diameter side of the cutting piece into a substantially L-shaped cross section by a bending means, and a thread groove on the outer peripheral surface by a groove cutting means while pressing the inner peripheral surface of the bent portion with an inner diameter holding jig. A groove forming step, a cutting step of completely cutting the end of the resin cylindrical body to the outer diameter side by the cutting means to form a seal ring, and a reversing step of reversing the bent part of the seal ring. A method of manufacturing a sealing device, comprising: a step and an assembling step of assembling the outer diameter side of the seal ring with a support member.