JPS6396822A - Manufacture of rubber contact - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method of manufacturing a rubber contact, and more particularly to a method of manufacturing a rubber contact in which a metal contact portion is formed on a rubber contact body made of silicone rubber. be.

[Technical background of the invention]

FIG. 1 is a sectional view of the rubber contact, and as is clear from this figure, the rubber contact has a structure in which a metal contact portion 2 is formed on the back surface of a button-shaped rubber contact body 1. The rubber contact main body 1 has a membrane part 1), and the head part 12 of the main body 1 is elastically supported by the membrane part 1), and by pressing the head part 12, the metal contact part 2 is lowered to contact the other contact (not shown).

When the pressure is released, the elasticity of the membrane portion 1) restores the original state.

Such rubber contacts are currently used as electrical contacts in various electrical devices, such as keyboards for computers, calculators, etc., but the rubber contacts have excellent weather resistance and durability, and also have a good contact feel when pressed. It is generally manufactured from silicone rubber, which has good properties. However, as is well known, silicone rubber has poor adhesive properties, and it is difficult to form the metal contact portion 2 using an adhesive.

For this reason, a method has been adopted in which the rubber contact body 1 is molded using a mold 3 as shown in FIG. 2, and at the same time the metal contact portion 2 is integrally formed. That is, the metal contact portion 2 is placed on the forming portion 32 of the metal contact portion 2 formed in the lower mold 31 of the mold, silicone rubber is charged, the upper mold 33 is closed, and integral molding is performed by heating and pressurizing. It was something. However, since the metal contact portion 2 is placed on the metal contact portion forming portion 32 of the lower mold 31, it is necessary to have a size slightly smaller than the forming portion 32. Therefore, there is a slight gap 3 between the metal contact part 2 (MJI surface and the lower die 31).
4 will result. When silicone rubber is charged in this state and a rubber contact is molded, the silicone rubber infiltrates into the gap 34 and as shown in the first drawing,
There was a drawback that burrs 13 were formed on the side surfaces of the metal contact portions 2 and the like. If such burrs 13 are formed, there is a risk that defects such as poor conductivity may occur in the rubber contacts.

[Summary of the Invention] The present invention has been made in view of the above points, and provides a method for manufacturing a rubber contact that does not cause burrs on the side surface of the metal contact portion when manufacturing a rubber contact having the above-described structure. The purpose is to provide

Therefore, the method for manufacturing a rubber contact according to the present invention is 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 silicone rubber having a predetermined shape. After manufacturing a metal contact portion by punching it into a shape, the metal contact portion is placed in the metal contact forming portion of a mold having a molding portion that approximately corresponds to the shape of the rubber contact body so that the metal surface is in contact with the mold surface. The silicone rubber is placed in a mold and heated and pressurized.

According to the method for manufacturing a rubber contact according to the present invention, in manufacturing the rubber contact, a rubber sheet is laminated on a metal plate and integrated by vulcanization, and then the laminate is cut into a predetermined shape. By using the silicone rubber, the silicone rubber is prevented from penetrating into the side surface of the metal contact portion, thereby eliminating the occurrence of burrs. That is, when punching out a laminate of a metal plate and a rubber sheet, the rubber sheet is compressed and punched out, but when the rubber sheet is restored after this work is completed, the rubber seal protrudes from the metal plate in the circumferential direction. will be restored. The present invention takes advantage of such a phenomenon, and its major feature is that the protruding portion generated during the punching process is used as a seal to prevent silicone rubber from penetrating.

[Detailed description of the invention]

According to the invention, a 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 mold 3 (lower mold 31) having a molding portion corresponding to the shape.

In the present invention, the metal contact portion 2 is made by laminating a rubber layer 22 on a metal plate 21, as shown in FIG. That is, the laminate 23 is manufactured by laminating unvulcanized or semi-vulcanized rubber on the metal plate 21 and vulcanizing the rubber in an integrated manner.

The metal plate 21 used for manufacturing this laminate is not fundamentally limited in the present invention, and metal contact portions conventionally used in this type of rubber contact can be effectively used. For example, it is possible to use nickel silver that is fully plated or coated with titanium.

It is clear that the rubber material to be laminated on the metal plate 21 needs to be selected so as to adhere well to the silicone rubber that will become the rubber contact body 1 and to integrate it. As such a rubber material, for example, silicone rubber, acrylonitrile butadiene rubber, chloroprene rubber, urethane rubber, butyl rubber, ethylene propylene rubber, etc. can be used.

The thickness of this unvulcanized or semi-vulcanized rubber layer is basically not limited. However, when the laminate 23 is manufactured by vulcanization and integrated and then processed into a predetermined collapsed shape by punching, the protruding portion 22 of the rubber layer 22
The protrusion amount Δt of 1 is the metal contact forming portion 32 of the mold 3.
It is preferable to make it slightly larger. Of course, the above ΔL depends on the conditions of the punching process, the type of rubber, etc.
cannot be controlled only by the thickness of the rubber layer 22, but it is preferably 0.1 to 3.
It is preferable to laminate the layers to a thickness of about mm. If it is less than 0.1 mm, Δt will be too small and the effect of providing the rubber layer 22 will be too small; if it exceeds 31M1l+, Δt will be too large and a well-molded rubber contact cannot be replaced. This is because there is a risk that it will disappear.

In this way, the unvulcanized or semi-vulcanized rubber layer is heated and pressurized to vulcanize it, and is integrated with the metal plate 21, and the rubber layer 22 is laminated thereon. The conditions commonly used for laminating metal-rubber layers can be effectively used. For example, a temperature of 150-170℃, a temperature of 50-170℃
The laminate 23 can be manufactured by heating and pressing at a pressure of 150 Kg/cut for 4 minutes or more.

The method of manufacturing such a laminate 23 is not limited to the method described above; for example, it can also be manufactured by applying adhesive to the metal plate 21 and laminating rubber sheets. it is obvious.

This laminate 23 is punched into the shape of an electrical contact, and the electrical contact portion 2
Manufacture.

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

It is clear that the pressure in this punching process is a major factor in controlling the Δt. This punching process compresses the rubber layer 22 without changing the shape of the metal plate 21 and forms a protruding portion 221 when the rubber layer 22 is restored. For this reason, the punching process is performed by cutting the laminate 23 from the rubber layer 22 toward the metal layer 21. After cutting the laminate 23 by cutting from the direction of the rubber layer 22 in this way,
A protruding portion 221 is formed in the rubber layer 22. That is, in the case of punching, the rubber layer 22 is on the blade side and the metal layer 21 is on the punch side.

The gold bait contact part 2 manufactured in this way is placed in the lower mold 3 of the mold 3.
The metal plate 21 is attached so as to be in contact with the electrical contact forming portion 32 formed in the metal plate 1 . In this case, since the protruding portion 221 has elasticity, it is preferable that the protruding portion 221 be slightly larger than the inner circumference of the metal contact forming portion 32. By making the gap a little larger in this way, the gap 3
4 will be completely sealed. In this case, Δt is preferably 0 than the inner circumference of the forming portion 32.
．． It is preferable to set it to be approximately 01 to 0.3n+m larger.

As described above, after the metal contact portion 2 is attached to the forming portion 22 so that the metal plate 21 is in contact with the mold 3, silicone rubber is placed in the mold 3, and the upper mold 33 is closed and heated and pressurized.

This heating and pressing step (which also serves as vulcanization) can be performed in the same manner as in conventional manufacturing methods. For example, 150-170
At a temperature of ℃, a pressure of 50-150 Kg/cal, 4
Rubber contacts are manufactured by heating and pressurizing for more than a minute.

Example A metal plate made of fully plated nickel silver with a thickness of 0.7 mm was prepared, and unvulcanized silicone rubber was applied to the metal plate to a thickness of 21 mm.
)1) Laminated in step 1) and vulcanized at 140°C for 6 minutes.

The N slope thus manufactured was punched out at a pressure of 1500 Kg/cd or higher to manufacture a circular metal contact portion. In this case, Δt of the protruding part is 0.05>0.0
Next, as shown in the first canvas drawing, the metal plate 2
Attach the metal contact part 2 so that 1 faces down, then insert silicone rubber, close the upper mold 33, and heat to 160°C.
Heat and pressure was applied for 6 minutes to produce a rubber contact.

As shown in the first drawing, the rubber contact manufactured in this manner was integrally bonded to the silicone rubber, and no burrs 13 were formed on the side surface of the metal contact portion 2.

〔Effect of the invention〕

As explained above, according to the method for manufacturing a rubber contact according to the present invention, a metal contact is manufactured by punching a laminate in which a metal plate and a rubber layer are laminated, and the rubber layer produced by this punching process is Since the rubber contact is manufactured using the protruding portion as a seal, there is an advantage that burrs are not generated on the side surface of the metal contact portion. This has the advantage of improving the manufacturing yield of rubber contacts and also improving reliability.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional rubber contact and a rubber contact manufactured in an embodiment according to the present invention, and FIG. 2 is a cross-sectional view of a conventional rubber contact manufacturing method and a mold used in an embodiment of the present invention. 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
... Gold B slope, 22 ... Rubber layer, 221 ... Protrusion part, 3 ... Mold, 32 ... Metal contact forming part, 34 ... Gap.

Claims (1)

[Claims] (1) In a method for manufacturing a rubber contact in which a metal contact portion is formed in a part of a rubber contact body made of silicone rubber having a predetermined shape,
After manufacturing a metal contact part by punching out a laminate in which a rubber layer is laminated on a metal plate into a predetermined shape, this metal contact part is placed in the metal contact part forming part of a mold having a molding part that approximately corresponds to the shape of the rubber contact body. 1. A method for manufacturing a rubber contact, which comprises attaching a silicone rubber so that its metal surface is in contact with a mold surface, charging silicone rubber into the mold, and heating and pressurizing it.