JPS6367454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an annular packing whose outer periphery is coated with a thin synthetic resin such as Teflon.

Annular packings, which are generally formed by coating the outer periphery of a rubber O-ring or D-ring with a synthetic resin such as Teflon or Fuso, have excellent abrasion resistance and chemical resistance, and are currently widely used. . The method for manufacturing this annular packing is to apply a cylindrical synthetic resin such as Teflon to the outer circumferential surface of a ring-shaped rubber, and then fire and integrate the two through a mold. However, in such conventional methods, the synthetic resin such as Teflon used is formed in advance into a long cylindrical shape with approximately the same diameter as the ring-shaped rubber, and this synthetic resin is The resin cylindrical body must be cut to have the same dimensions as the desired thickness and width of the annular packing. In other words, before firing with a mold, a primary process of forming a synthetic resin such as Teflon into a cylindrical shape and cutting it to the desired width is required, which reduces processing costs and time losses associated with this primary process. The actual situation is that the production cost of the final annular packing increases due to these factors, and the packing becomes expensive.

The present invention is an attempt to improve the conventional situation as described above, and an object of the present invention is to facilitate the manufacture of an annular packing whose outer periphery is coated with a synthetic resin such as Teflon. . That is, in the present invention, a synthetic resin such as Teflon that covers the outer periphery of an annular packing is formed into a flat plate shape in advance, and when the synthetic resin such as Teflon is transformed from a flat plate state to a cylindrical shape, the same deformation process is performed by molding rubber. The invention is characterized in that it is carried out at the same time as processing, and the gist of the present invention is that a flat ring made of synthetic resin such as Teflon is sandwiched between an annular projection formed on a lower mold and a holding ring. After inserting the core into the lower mold and bending the inner periphery of the flat ring downward to form a cylindrical shape, a ring shape is placed on the inner periphery of the synthetic resin such as Teflon formed into the cylindrical shape. The structure is such that the rubber is charged, the upper mold is placed over the mold, the mold is heated under pressure, and the two are fixed and integrated by firing.

Specific embodiments of the present invention will be described below with reference to illustrative drawings. 1 to 7 are drawings showing a first embodiment, and this embodiment has a D-ring shape whose outer peripheral surface side is curved semicircularly as shown in FIGS. 6 and 7. This is an example in which an annular packing 1a is formed. In the drawing, 2a is a mold for heating and forming the annular packing 1a;
is composed of a bottom mold 3, a lower mold 4, a presser ring 5, a core 6, and an upper mold 7. The center part of each of the bottom mold 3, the lower mold 4, and the presser ring 5 has an inner diameter that is approximately the same as the outer diameter of the core 6 and the upper mold 7 so that the core 6 and the upper mold 7 can be fitted therein. Insertion holes 8, 9, and 10 are drilled, respectively. Further, the upper edge of the core 6 and the lower edge of the upper mold 7 have rising surfaces 11a, 11b and horizontal surfaces 12a, respectively.
Recesses 13a and 13b having 12b are formed relative to each other. The inner peripheral surface of the lower mold 4 has the above-mentioned concave portions 13a, 13 in the assembled state of the mold 2a.
A groove 1 having a semicircular cross section at a position corresponding to b
4 is engraved along the circumferential direction. Same concave groove 14
A fitting part 16 of the presser ring 5 is formed with an annular protrusion 15 at the upper position, while a presser part 19 that can be fitted into the fitting part 16 is formed at the lower end of the presser ring 5. It is formed. The mold 2a formed in this manner has a lower mold 4 placed and fixed on a bottom mold 3 as shown in FIG. The shaped ring 17 is placed on the holding part 19 of the holding ring 5.
When the flat ring 17 is fitted into the fitting part 16, the flat ring 17 is held between the annular protrusion 15 and the holding part 19. In this state, when the core 6 is fitted into the insertion holes 9 and 8 from the insertion hole 10 side, the outer peripheral surface of the core 6 is fitted through the fitting operation as shown in FIG. Therefore, the flat ring 17
The inner peripheral edge portion of the tube is bent downward to form a cylindrical shape. In the state in which the flat ring 17 is bent into a cylindrical shape in this manner, the concave portion 13a of the core 6 as shown in FIG.
A separately formed ring-shaped rubber 18 is inserted into the inside,
In addition, by bringing the concave portion 13b of the upper die 7 into contact with the upper half of the ring-shaped rubber 18, and pressing the die 2a from above and below through an appropriate press device (not shown), the fifth As shown in the figure, ring-shaped rubber 18
is compressed and bulges into the groove 14 while pressing the synthetic resin a whose outer peripheral side is cylindrical through the pressing action of the recessed parts 13a and 13b on both the upper and lower surfaces and the circumferential surface. Become. By heating the mold 2a in this state for a certain period of time, the ring-shaped rubber 18 and the synthetic resin a are fixed and integrated, and after that, the unnecessary portion of the synthetic resin a is cut out, as shown in FIG. And an annular packing 1a as shown in FIG. 7 is obtained.

8 to 14 are drawings showing a second embodiment, and this embodiment is a D-ring-shaped annular packing 1b whose inner peripheral surface side is curved as shown in FIGS. 13 and 14. This is an example of forming a . The mold 2b used for this is composed of a lower mold 4', a presser ring 5', a core 6', and an upper mold 7', as shown in the figure. A concave portion 20a is formed in the lower mold 4' and has an inner diameter that is approximately the same as the outer diameter of the core 6' and the upper mold 7' so that the core 6' and the upper mold 7' can be fitted therein. The concave portion 20a has a horizontal surface 21a and an inner circumferential surface 22 that is continuous with the horizontal surface 21a and has a quadrant shape.
a is formed. Further, an annular protrusion 15' is provided at an upper position of the concave portion 20a, and a fitting portion 16' for the presser ring 5' is formed. The inner diameter of the holding ring 5' is set to be approximately the same as the outer diameter of the core 6' so that the core 6' can be fitted therein. On the other hand, a horizontal surface 2 is formed on the lower edge of the upper mold 7' in correspondence with the recessed portion 20a.
1b and a recessed portion 2 having a quadrant-shaped inner circumferential surface 22b.
0b is formed. Similarly to the first embodiment, the mold 2b formed in this way is made of synthetic resin a such as Teflon between the annular protrusion 15' of the lower mold 4' and the presser ring 5', as shown in FIG. When the flat ring 17 is clamped, and in this state the core 6' is fitted into the recessed part 20a via the holding ring 5', the inner peripheral edge of the flat ring 17 as shown in FIG. The portion is bent downward by the core 6' to form a cylindrical shape. With the flat ring 17 bent into a cylindrical shape in this manner, the core 6' and the presser ring 5' are removed as shown in FIG. 11, and the ring rubber 18 is inserted into the concave portion 20a. In this state, the mold 2b is pressed from above and below using an appropriate press device, as shown in FIG. 12. As shown in FIG.
Quadrant inner peripheral surfaces 22a and 2 of 0a and 20b
It will bulge out along line 2b. By heating the mold 2b in this state for a certain period of time, the synthetic resin a formed in the cylindrical shape described above is fixedly integrated with the outer peripheral portion of the ring-shaped rubber 18. Then, by cutting off unnecessary parts of the synthetic resin a, an annular packing 1b as shown in FIGS. 13 and 14 can be obtained.

As described above, the present invention allows a flat ring made of a synthetic resin such as Teflon to be bent into a cylindrical shape through the heat-forming mold during the heat-forming of the annular packing. The flat ring to be used can be obtained extremely easily by punching out a sheet of synthetic resin, so as in the conventional method, the synthetic resin is first formed into a cylindrical shape, and then this is cut to the desired thickness and width of the packing. It is possible to manufacture annular packings without performing such inefficient primary processing. As a result, the manufacturing process of the annular packing can be simplified compared to the conventional method, and the manufacturing time can be shortened.
The excellent effect of reducing manufacturing costs has been achieved.

In addition, in the present invention, as described above, a flat ring made of synthetic resin such as Teflon is bent into a cylindrical shape using a heating mold, and a ring-shaped rubber is applied to the inner peripheral surface of the synthetic resin. By performing pressure firing in the charged state, it was possible to obtain an annular packing whose outer circumferential surface only was coated with synthetic resin.

[Brief explanation of drawings]

1 to 7 are drawings showing the first embodiment, in which FIG. 1 is an exploded sectional view of a mold, and FIGS. 2 to 5 are explanatory views of the manufacturing process of an annular packing using the same mold. , Fig. 6 is an external perspective view of the annular packing, Fig. 7
The figure is a longitudinal cross-sectional view of the same packing. Moreover, FIGS. 8 to 14 are drawings showing the second embodiment, in which FIG. 8 is an exploded sectional view of the mold, and FIGS. 9 to 12 are explanations of the manufacturing process of an annular packing using the same mold. 13 is an external perspective view of the annular packing, and FIG. 14 is a longitudinal sectional view of the same packing. 1a, 1b... Annular packing, 2a, 2b...
Mold, 3... Bottom mold, 4, 4'... Lower mold, 5, 5'...
...Press ring, 6, 6'... Core, 7, 7'... Upper die, 8, 9, 10... Insertion hole, 11a, 11b...
...Rising surface, 12a, 12b...Horizontal surface, 13
a, 13b...Concave portion, 14...Concave groove, 15,1
5'... Annular projection, 16, 16'... Fitting part, 17
... Flat ring, 18 ... Ring-shaped rubber, 19
... Pressing part, 20a, 20b ... Recessed part, 21
a, 21b...Horizontal surface, 22a, 22b...Inner peripheral surface, a...Synthetic resin.

Claims (1)

[Claims] 1. Insert the core into the lower mold with a flat ring made of synthetic resin such as Teflon sandwiched between the annular protrusion formed on the lower mold and the holding ring, and push the inner peripheral edge of the flat ring downward. After bending it into a cylindrical shape, a ring-shaped rubber is inserted into the inner circumferential side of the synthetic resin such as Teflon, which is formed into a cylindrical shape, and an upper mold is placed over it, heated under pressure, and fired. A method for manufacturing an annular packing, characterized in that the synthetic resin is fixed and integrated on the outer peripheral surface of the ring-shaped rubber.