JP2003086043A - Make break contact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low resistance type make break contact capable of greatly contributing to enhancement of durability and reliability of an electronic apparatus and to expansion of its applicable range, by suppressing arc discharge without making the apparatus complicated and large-sized and increasing its cost. SOLUTION: A movable contact 10 is composed of an elastic body 11 having conductivity and a metallic linear bodies 12 neatly arranged in a crossing direction at a prescribed pitch and embedded in the elastic body 11, and the elastic body 11 is slightly more protruded than each linear body 12 on the surface side in contact with a fixed contact. When this contact is closed, a contact resistance is lowered by forcing the linear body 12 into metallic contact with the fixed contact by the deflection of the elastic body 11, and when it is dissociated, the linear body 12 is separated from the fixed contact prior to the elastic body 11 to suppress the arc discharge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching contact used for opening and closing an electric circuit, and more particularly to a low resistance type switching contact having a low contact resistance between the contacts.

[0002]

2. Description of the Related Art For example, as shown in FIG. 5, in a push button switch, a movable contact 4 is arranged on a convex seat 3 provided on the inner bottom of a hat-shaped rubber holder 2 having a thin flexible portion 1. Using the elastic deformation of the flexible portion 1, for example, the movable contact 4 is brought into contact with and separated from the fixed contact 6 provided on the substrate 5.

By the way, in consideration of the moldability of the movable contact 4 itself and the bondability with the rubber holder 2,
A so-called conductive rubber obtained by adding conductive carbon black or metal particles to a rubber-based material is often used. However, when such a conductive rubber is used, the contact resistance (electrical resistance) between the movable contact 4 and the fixed contact 6 becomes high, and under a use condition in which a high current flows, heat generation becomes severe and melting occurs. Combustion or the like occurs, and therefore its application is limited to ON, OFF, etc.

Therefore, various types of low resistance type open / close contacts in which a metal is arranged on the contact surface of the movable contact with the fixed contact have been conventionally developed, for example, Japanese Patent Laid-Open Nos. 8-276435 and 2001-184964. Japanese Patent Laid-Open No. 11-238423 describes a laminated structure in which a rubber layer is laminated on a metal plate, and a sandwich structure in which a woven or non-woven fabric of metal fibers is laminated on both surfaces of the rubber layer.

[0005]

However, as described above, according to the low resistance type opening / closing contact using the rubber laminated metal as the movable contact, the arc discharge is generated when the contact is opened / closed, especially when the contact is opened. The phenomenon that occurs often occurs and there is a problem that durability reliability is poor. In order to suppress this arc discharge, some measures have been taken such as making the contacts larger, arranging two contacts in series, or sealing the contacts in an inert gas. According to the countermeasures, it causes an increase in the complexity and size of electric devices,
The cost burden also increases. The present invention has been made in view of the above-described conventional problems, and the problem is that it is possible to suppress the arc discharge without increasing the size and cost of the electronic device, durability durability reliability. It is to provide a low resistance type switching contact which greatly contributes to the improvement of

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, one of a pair of contact members that can be opened and closed has a conductive elastic body and a metal linear body alternately in a cross section. It is characterized in that the elastic body is slightly projected from the linear body on the contact surface side with the counterpart contact. In the switching contact thus configured, when the contact is closed, the elastic body bends so that the linear body makes metal contact with the counterpart contact, thereby sufficiently lowering the contact resistance. On the other hand, when the contact is opened, the metal linear body separates from the mating contact ahead of the elastic body, and at this time, since the conductive elastic body maintains conduction, arc discharge does not occur, and During this period, a voltage drop occurs from the conductive elastic body toward the mating contact, so that arc discharge does not occur even when the conductive elastic body subsequently separates from the mating contact.

According to the present invention, the linear body of the above metal is 5 to 10 μm.
It is preferable that the elastic bodies are arranged with a gap of m and the elastic body is filled in the gap of the linear body. If the gap between the metal linear objects is smaller than the above range, the amount of elastic material will be insufficient relative to this, and the preferential opening of the linear objects will be incomplete when the contacts are opened, resulting in arc discharge. On the other hand, when the gap between the linear bodies is larger than the above range, the amount of the conductive elastic body increases relative to this and the contact resistance increases. In the present invention, the conductive elastic body may be composed of a composite material in which a conductive material is dispersed in a polymer material, but the types of the polymer material and the conductive material used here are arbitrary. The polymer materials include, for example, silicone rubber, butyl rubber, chloroprene rubber, urethane rubber, etc., as well as low density polyethylene, acrylic resin having PTC characteristics, etc., and the conductive materials include carbon, silver, copper, etc. It is possible to use a simple substance or an alloy thereof.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show one embodiment of a switching contact according to the present invention. The open / close contact is incorporated in the push button switch. In FIGS. 1 and 2, reference numeral 10 denotes a movable seat arranged on the convex seat 3 (FIG. 5) provided on the inner bottom of the rubber holder 2. Represents a contact. The movable contact 10 includes an elastic body 1 having conductivity.
1 and a metal linear body 12 which is embedded in the elastic body 11 in such a manner as to be arranged in order in a transverse direction at a predetermined pitch.

The elastic body 11 having conductivity is made of a composite material in which conductive particles such as carbon, silver, copper and the like or alloys thereof are added to silicone rubber. In this case, the amount of the conductive particles added is equal to that of the elastic body 11
The electrical resistance (specific resistance) is set to 1 to 10 Ωcm as a guide. On the other hand, the linear bodies 12 have a diameter of 25 to 100 μm here and are arranged with a gap of 5 to 10 μm. As the metal forming the linear body 12, not only silver simple substance but also tin, nickel, copper, etc.
Alloys with 0.1-1.0 wt% addition, gold, nickel,
Although alloys such as copper and palladium can be used, it is preferable to use silver alloys because they have good conductivity and excellent strength.

On the contact surface side of the movable contact 10 with the fixed contact 6 (FIG. 5), the end face 11a of the elastic body 11 projects slightly from the end face 12a of each linear body 12 by a height δ, The contact surface of the movable contact 10 with the fixed contact 6 has a shape having fine irregularities. Therefore, the protruding height δ of the elastic body 11 is a minute height of about several μm, which allows the movable contact 1 to close the contact now.
When 0 is brought into contact with the fixed contact 6, the elastic body 11 first comes into contact with the fixed contact 6 to cause bending, and the bending causes the linear body 1 to move.
The end surface of 2 is exposed at the contact surface and comes into contact with the fixed contact 6.

The movable contact 10 can be manufactured by utilizing, for example, a technique for manufacturing a semiconductor substrate or a technique for manufacturing an anisotropic conductive film used for a continuity test. The manufacturing technique of this anisotropic conductive film is to fill a large number of fine holes formed in an insulating film with a metal substance by electrolytic plating or electroless plating. For example, JP-A-3-266306 and JP-A-6-306306. No. 232222. In order to manufacture the movable contact 10, in the technique for manufacturing an anisotropic conductive film described above, a conductive elastic sheet in which conductive particles are added to silicone rubber is prepared in place of the insulating film. After forming a large number of fine holes in the hole, the fine holes are filled with the metal forming the linear body 12 by the above-mentioned electrolytic plating or electroless plating, and then the movable contact 10 can be punched out. Good. Further, in order to form minute irregularities on the contact surface side of the fixed contact 6, it suffices to slightly elute the end portion of the linear body 12 by etching, whereby the movable contact 10 is completed. The movable contact 10 thus obtained is set in a mold and integrally molded with the rubber holder 2 (FIG. 5) to be incorporated into a push button switch.

The operation of the switching contacts having the movable contact 10 as a constituent element will be described below with reference to FIG. First, when the rubber holding body 2 is pushed in to close the contact to bring the movable contact 10 into contact with the fixed contact 6, the end of the conductive elastic body 11 constituting the movable contact 10 is bent, and the movable contact 10 is Full contact with the fixed contact 6 (Fig. 3). Therefore, in this state, the linear body 12 makes metal contact with the fixed contact 6 at multiple points, whereby the contact resistance (electrical resistance) is sufficiently low (10 to 100 Ω as an example), and heat generation at the contact interface is suppressed. Therefore, the conduction state is stably maintained. On the other hand, when the contact is opened, the metal linear body 12 separates from the fixed contact 6 prior to the elastic body 11 as shown in the figure, and in this state, the conductive elastic body 11 maintains the conduction of the contact. Arc discharge does not occur. Further, in this state, a voltage drop occurs from the conductive elastic body 11 toward the fixed contact 6, and the potential difference between the contacts is reduced. Therefore, after that, when the movable contact 10 is completely separated from the fixed contact 6 as shown in FIG. As described above, according to the present opening / closing contact, arc discharge at the time of opening / closing is suppressed, so that the durability reliability is significantly improved, and it can be widely applied as a low resistance type. Further, since the elastic body 11 forming the movable contact 10 functions as a cushioning material that suppresses bounce when the contact is opened and closed, unnecessary noise is reduced.

Here, as a method of manufacturing the movable contact 10, various methods can be adopted other than the use of the above-mentioned technology for manufacturing an anisotropic conductive film. FIG. 4 shows one such method, in which slits 21 are formed in a grid pattern on one surface of a metal disk 20 prepared in advance by etching, and conductive particles are added to a polymer material in the slits 21. The rubber-based composite material 22 is filled. As a result, the rubber-based composite material 22 is used as it is as a conductive elastic body, and the remaining portion of the metal disk 20 divided by the slit 21 is directly used as a linear body, and the movable contact 10 of the composite structure is provided.
Will be obtained. The movable contact 10 is completed by slightly eluting the linear body by etching, as in the above embodiment. Although not shown, it is also possible to adopt a method of filling the gaps between the bundles of thin metal wires arranged at a predetermined pitch with the conductive composite material.

[0014]

As described above, according to the switching contact according to the present invention, the arc discharge at the time of switching the contact can be suppressed, which greatly contributes to the improvement of the durability and reliability.
Also, since it has only a composite structure in which elastic bodies having conductivity and metal linear bodies are alternately laminated in the transverse direction, it is possible to widely use it as a low resistance type without inviting complicated and large electronic devices. Becomes

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a movable contact that constitutes a switching contact according to an embodiment of the present invention in a half-divided state.

FIG. 2 is an enlarged cross-sectional view showing a main part structure of the movable contact shown in FIG.

FIG. 3 is a cross-sectional view showing a usage mode of the main opening / closing contacts in order.

FIG. 4 is a perspective view showing one method of manufacturing a movable contact.

FIG. 5 is a cross-sectional view showing the structure of a push button switch to which the main opening / closing contact is applied.

[Explanation of symbols]

2 rubber holder 6 fixed contacts 10 movable contacts 11 Conductive elastic body 12 Metal linear objects

Claims (3)

[Claims] 1. One of a pair of openable and closable contact members has a composite structure in which an elastic body having conductivity and a metal linear body are alternately laminated in a transverse direction, and at a contact surface side with a counterpart contact. An opening / closing contact, wherein the elastic body is slightly protruded from the linear body. 2. The metal linear body is arranged with a gap of 5 to 10 μm, and the elastic body is filled in the gap of the linear body. Switching contact. 3. The elastic body is made of a composite material in which a conductive material is dispersed in a polymer material.
Or the switching contact described in 2.