JPH0693335B2 - Rubber contact manufacturing method - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for manufacturing a rubber contact, and more particularly to a method for manufacturing a rubber contact in which a metal contact portion is formed on a rubber contact body made of silicone rubber. is there.

[Technical Background of the Invention] FIG. 1 is a sectional view of a rubber contact. As is clear from this figure, the rubber contact is formed by forming a metal contact portion 2 on the back surface of a button-shaped rubber contact body 1. It has a structure. The rubber contact body 1 has a film portion 11, and the body 1
The head 12 is elastically supported by the film portion 11, and by pressing the head 12, the metal contact portion 2 descends and comes into contact with the other contact (not shown). ing.

When the pressing is released, the elasticity of the film portion 11 restores the original state.

Such rubber contacts are currently used as electric contacts for various electric devices such as keyboards for computers and calculators. The rubber contacts are excellent in weather resistance and durability, and have a feeling of contact when pressed. It is generally made of silicone rubber so that However, as is well known, silicone rubber has poor adhesiveness, and it is difficult to form the metal contact portion 2 with an adhesive when forming the metal contact portion 2.

For this reason, a method is employed in which the metal contact portion 2 is integrally formed at the same time that the rubber contact body 1 is molded by using a mold 3 as shown in FIG. That is, the metal contact portion 2 is laid on the forming portion 32 of the metal contact portion 2 formed on the lower die 31 of the die, the silicone rubber is charged, the upper die 33 is closed, and heat and pressure are applied for integral molding. It was a thing. However, the metal contact portion 2 is a metal contact portion forming portion of the lower die 31.
Since it is laid on 32, it is necessary to make it slightly smaller than the forming portion 32. Therefore, the metal contact portion 2
A slight gap 34 is created between the side surface and the lower die 31. In this state, when the silicone rubber is charged and the rubber contact is molded, the silicone rubber penetrates into the gap 34, and as shown in the left diagram of FIG. There was a drawback that caused. If such burrs 13 are generated, there is a risk that defects such as poor continuity may occur at the rubber contacts.

[Outline of Invention]

The present invention has been made in view of the above points, and in manufacturing a rubber contact having the above-described structure, it is an object of the present invention to provide a method for manufacturing a rubber contact that does not cause burrs on the side surface of the metal contact portion. To aim.

Therefore, the method of manufacturing a rubber contact according to the present invention is a method of manufacturing a rubber contact in which a metal contact portion is formed on a part of a silicone rubber rubber contact body having a predetermined shape, and a laminated body in which a rubber layer is laminated on a metal plate is predetermined. After manufacturing the metal contact part by punching into a shape, the metal contact part is formed on the metal contact part forming part of the mold having a molding part substantially corresponding to the rubber contact body shape so that the metal surface contacts the mold surface. It is characterized in that it is mounted, silicone rubber is charged into a mold and heated and pressed.

According to the method for producing a rubber contact according to the present invention, in producing the rubber contact, a rubber sheet is laminated on a metal plate to be vulcanized and integrated, and then the laminate is cut into a predetermined shape. Since the silicone rubber was prevented from entering the side surface of the metal contact part by using
No flash will occur. That is, when a laminated body of a metal plate and a rubber sheet is punched out, the rubber sheet is compressed and punched out, but when the rubber sheet is restored after the completion of this work, the rubber seal protrudes from the metal plate in the circumferential direction. Will be restored. The present invention utilizes such a phenomenon, and is characterized by using the protruding portion generated in the punching process as a seal for preventing silicone rubber from entering.

[Specific Description of the Invention]

According to the present invention, the rubber contact body 1 as shown in FIG.
The metal contact portion 2 is attached to the metal contact portion forming portion 32 of the die 3 (lower die 31) having a molding portion corresponding to the shape.

In the present invention, the metal contact portion 2 is formed by laminating a rubber layer 22 on a metal plate 21 as shown in FIG. That is, the unvulcanized or semi-vulcanized rubber is laminated on the metal plate 21 and vulcanized and integrated to manufacture the laminate 23.

The metal plate 21 used for manufacturing this laminated body is not basically limited in the present invention, and the metal contact portion conventionally used for this type of rubber contact can be effectively used. For example, nickel silver plated with gold or titanium coated can be used.

The rubber material laminated on the metal plate 21 is the rubber contact body 1
It is clear that it is necessary to select a rubber material that adheres and integrates the silicone rubber that becomes
As such a rubber material, for example, silicone rubber, acrylonitrile butadiene rubber, chloroprene rubber, urethane rubber, butyl rubber, ethylene propylene rubber or the like can be used.

The thickness of the unvulcanized or semi-vulcanized rubber layer is not basically limited. However, when the laminate 23 is manufactured by vulcanization and integrated and then processed into a predetermined shape by punching, the protruding amount Δt of the protruding portion 221 of the rubber layer 22 is slightly larger than the metal contact portion forming portion 32 of the mold 3. Is preferred. Of course, the Δt changes depending on the conditions of punching, the type of rubber, etc., so it cannot be controlled only by the thickness of the rubber layer 22, but it is preferable to stack it to about 0.1 to 3 mm. . If it is less than 0.1 mm, Δt is too small and the effect of providing the rubber layer 22 is too small, and if it is more than 3 mm, Δt is too large and it may not be possible to obtain a rubber contact with good molding. Because there is.

In this way, the unvulcanized or semi-vulcanized rubber layer is heated and pressurized to be vulcanized, and is integrated with the metal plate 21 and the rubber layer 22 is laminated. The conditions applied to the metal-rubber layer lamination can be effectively used. For example, the laminate 23 can be manufactured by heating and pressurizing at a temperature of 150 to 170 ° C. and a pressure of 50 to 150 kg / cm ² for 4 minutes or more.

The manufacturing method of such a laminated body 23 is not sinusoidal to the above-described method, and can be manufactured by, for example, applying an adhesive to the metal plate 21 and laminating rubber sheets. it is obvious.

The laminated body 23 is punched into an electric contact shape to manufacture the electric contact portion 2.

The type of punching is basically not limited in the present invention. For example, conventional punching techniques such as die set punching can be effectively used.

It will be apparent that the pressure in this punching process is a major factor in controlling Δt. This punching process compresses the rubber layer 22 without changing the shape of the metal plate 21, and when the rubber layer 22 is restored, the protruding portion 22 is formed.
To form one. Therefore, the punching process is performed by cutting the laminated body 23 from the rubber layer 22 toward the metal layer 21. By thus cutting from the direction of the rubber layer 22, the protruding portion 221 is formed in the rubber layer 22 after the laminate 23 is cut. That is, in the case of removing the die set,
The rubber layer 22 is on the blade side, and the metal layer 21 is on the punch side.

The metal contact portion 2 manufactured as described above is connected to the lower mold 31 of the mold 3.
The metal plate 21 is attached to the electric contact portion forming portion 32 formed in the above. In this case, the protruding portion
Since 221 has elasticity, the metal contact portion forming portion 3
It should be slightly larger than the inner circumference of 2. This is because the gap 34 is completely sealed by slightly increasing the size. In this case, Δt is preferably set to be larger by 0.01 to 0.3 mm than the inner circumference of the forming portion 32.

As described above, the metal contact portion 2 is formed on the forming portion 22 by the metal plate 21.
Is attached so that it contacts the mold 3, silicone rubber is placed in the mold 3, and the upper mold 33 is closed and heated and pressed.

This heating / pressurizing step (which also serves as vulcanization) can be performed in the same manner as the conventional manufacturing method. For example, at a temperature of 150-170 ℃, a pressure of 50-150 kg / cm ² , heat and pressurize for 4 minutes or more,
Manufacture rubber contacts.

Example A metal plate having a thickness of 0.7 mm and plated with gold was prepared, and unvulcanized silicone rubber was laminated on the metal plate to a thickness of 2 mm and vulcanized at 140 ° C. for 6 minutes. The thus produced laminated plate was die-set removed at a pressure of 1500 kg / cm ² or more to produce a circular metal contact portion. In this case, Δt of the protruding portion was 0.05 to 0.06 mm.

Next, as shown in the right diagram of FIG. 1, the metal contact portion 2 is attached to the metal contact portion forming portion 32 (inner diameter 4.07 mmφ) of the lower mold 32 so that the metal plate 21 is located below, and then the silicone is used. After charging rubber and closing the upper mold 33, heating and pressurizing was performed at 160 ° C. for 6 minutes to manufacture a rubber contact.

The rubber contact thus manufactured was integrally bonded to the silicone rubber as shown in the right drawing of FIG. 1, and the flash 13 did not occur on the side surface of the metal contact portion 2.

〔The invention's effect〕

As described above, according to the method for producing a rubber contact according to the present invention, a metal contact portion is produced by punching a laminated body in which a metal plate and a rubber layer are laminated, and a rubber layer produced by the punching process. Since the rubber contact is manufactured by using the protruding portion as a seal, there is an advantage that burrs do not occur on the side surface of the metal contact portion. Therefore, there is an advantage that the manufacturing yield of the rubber contact is improved and the reliability is also improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a conventional rubber contact and a rubber contact manufactured in one embodiment of the present invention, and FIG. 2 is a sectional view of a conventional rubber contact manufacturing method and a mold used in one embodiment of the present invention. FIG. 3 and FIG. 3 are a cross-sectional view of the laminate and a cross-sectional view of the electrical contact portion. 1 ... rubber contact body, 2 ... metal contact part, 21 ... metal plate, 22 ...
A rubber layer, 221, a protruding portion, 3 ... a mold, 32 ... a metal contact forming portion, 34 ... a gap.

Continuation of the front page (56) Reference JP-A-56-132717 (JP, A) JP-A-57-103218 (JP, A) JP-A-59-157924 (JP, A) JP-A-60-235317 (JP , A) JP 61-214314 (JP, A) JP 63-96821 (JP, A) JP 63-96823 (JP, A) JP 63-96824 (JP, A) 56-152122 (JP, U)

Claims (1)

[Claims] 1. A method for manufacturing a rubber contact in which a metal contact portion is formed on a part of a rubber contact body made of a silicone rubber having a predetermined shape, and a metal contact portion is formed by punching out a laminate having a rubber layer laminated on a metal plate into a predetermined shape. After manufacturing, the metal contact part is attached to a metal contact part forming part of a mold having a molding part substantially corresponding to the shape of the rubber contact body so that the metal surface is in contact with the mold surface, and the silicone rubber is molded into a metal mold. A method for producing a rubber contact, which comprises charging in a mold and applying heat and pressure.