JP2007242505A - Contact structure and switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact structure capable of avoiding contact welding; and to provide a switch using it. <P>SOLUTION: Fixed contacts 19 and 20 of fixed pieces 15 and 16 are formed out of a silver alloy, moving contacts 18 of a moving piece 14 contacting to and separating from the fixed contacts 19 and 20 are formed out of a conductive plastic material, and thus they are formed out of different kinds of materials different in property values such as a melting point, whereby contact welding between the fixed contacts 19 and 20 and the moving contacts 18 is avoided, and reliability and a service life are improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a contact structure and a switch including the contact structure.

A switch, for example, a microswitch, switches a contact by quickly moving a movable contact from one fixed contact to the other fixed contact in accordance with an operation of a push button as an actuator (for example, Patent Documents). 1).
JP 2000-215751 A

  In such a microswitch contact structure, both the fixed contact and the movable contact are made of the same kind of metal material as silver alloy. For this reason, when the movable contact contacts and separates from the fixed contact, particularly at the time of separation. There is a problem in that contact welding is likely to occur due to the generated arc and the like, and the contact life is shortened.

  The present invention has been made in view of the above points, and an object thereof is to provide a contact structure that can avoid contact welding and a switch using the contact structure.

  (1) The contact structure of the present invention is a contact structure including a fixed contact and a movable contact contacting and leaving the fixed contact, and one of the fixed contact and the movable contact is made of a conductive plastic material, The other contact is made of a metal material.

  According to the present invention, one of the fixed contact or the movable contact contacting and separating from the fixed contact is made of a conductive plastic material, and the other contact is made of a metal material, that is, a melting point or the like. Since it is composed of dissimilar materials having greatly different physical property values, contact welding does not occur, and reliability and life are greatly improved.

  (2) In one embodiment of the contact structure of the present invention, the metal material is a silver alloy.

  According to this embodiment, the contact resistance and heat resistance are good.

  (3) The switch of the present invention is connected to a movable piece having a movable contact at the free end, a receiving member coupled to the terminal and supporting the base end of the movable piece in a swingable manner, and another terminal. A fixed piece having a fixed contact facing the free end of the movable piece, and a spring member that snaps the movable piece to bring the movable contact into and out of contact with the fixed contact. One of the movable contacts is made of a conductive plastic material, and the other contact is made of a metal material.

  According to the present invention, one of the fixed contact or the movable contact contacting and separating from the fixed contact is made of a conductive plastic material, and the other contact is made of a metal material, that is, a melting point or the like. Since it is composed of dissimilar materials having greatly different physical property values, contact welding does not occur, and the life of the switch is greatly improved.

  (4) In a preferred embodiment of the present invention, the spring member is formed integrally with the movable piece having a spring property.

  According to this embodiment, the number of parts and the number of assembly steps can be reduced.

  (5) In another embodiment of the present invention, the one contact point made of the conductive plastic material is integrated with the fixed piece or the movable piece by insert molding.

  According to this embodiment, it is possible to obtain a fixed piece or a movable piece having good strength and durability.

  According to the present invention, since one contact of the fixed contact or the movable contact contacting and separating from the fixed contact is made of a conductive plastic material and the other contact is made of a metal material, the welding of the contacts Will not occur, and reliability and lifetime will be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a front view of a part of a microswitch according to the present invention, and FIG. 2 is an exploded perspective view thereof.

  The microswitch includes a hollow switch case 1 made of an insulating resin material. As shown in FIG. 2, the switch case 1 includes a case body 1a having three terminals 2, 3, and 4 mounted with inserts, The cover 1b is connected to the case body 1a by pins 5.

  A pair of mounting holes 13 are formed in the main body case 1a.

  The cover 1b is equipped with a switch operating lever 6 supported so as to be swingable around a fulcrum p, an actuator 7 displaced by the lever 6, and a spring 8.

  The switch case 1 includes a snap-action type switching mechanism 9. Below each of the terminals 2, 3 and 4, terminal screws 10, 11 and 12 for connecting wires are provided.

  The switching mechanism 9 includes a movable piece 14 made of a leaf spring in which a base end portion (a left end portion in FIG. 1) is caulked and connected to an inner end portion of a terminal 2 serving as a common terminal, and an inner end of the terminal 3 serving as a normally closed terminal. A fixed piece 15 that is caulked and connected to the inner part, and a fixed piece 16 that is caulked and connected to the inner end of the terminal 4 that is a normally open terminal. A pair of snap-action spring pieces 14 a extending toward the end are elastically curved, and their tips are locked to the front end of the receiving member 17 fixed to the terminal 2.

  The movable piece 14 is cantilevered so as to be able to be bent and swung up and down with a connection point with the terminal 2 as a fulcrum, and the pair of fixed pieces 15 and 16 are opposed to the free end of the movable piece 14 from above and below. Has been deployed.

  Fixed contacts 19, 20 facing the upper and lower movable contacts 18 provided at the free end of the movable piece 14 are provided on the respective fixed pieces 15, 16, and the movable piece 14 swings up and down to move the movable contact 18. However, the contact state between the terminal 2 and the terminal 3 or the conduction state between the terminal 2 and the terminal 4 can be obtained by contacting the fixed contact 19 or the fixed contact 20. The inner end of the actuator 7 is the operation end facing the movable piece 14 from the upper surface to the base end side.

  The switching mechanism 9 is configured as described above. Normally, as shown in FIG. 1, the movable contact 18 of the movable piece 14 is pressed against the fixed contact 19 of the fixed piece 15 so that the terminals 2 and 3 are electrically connected. Stable.

  When the lever 6 is swung downward from the state shown in FIG. 2 and the actuator 7 is displaced, the movable piece 14 returns, and the movable contact 18 of the movable piece 14 contacts the fixed contact 20 of the fixed piece 16 and becomes conductive. Then, contact switching is performed.

  When the swinging operation of the lever 6 is released, the movable piece 14 returns to the original posture shown in FIG.

  In the contact structure of this embodiment, the movable contact 18 of the movable piece 14 is made of a conductive plastic material, and the fixed contact 19 of the fixed piece 15 and the fixed contact 20 of the fixed piece 16 are made of a silver alloy. .

  Examples of the conductive plastic material include a conductive polymer such as polyacetylene, a plastic mixed with metal powder as a conductive filler, or an ion conductive polymer.

  Such a conductive plastic material has the advantage that it is cheap because it uses petroleum as a raw material, and is light and easy to process, in addition to the advantage that it does not rot or rust.

  The movable contact 18 is integrated with the movable piece 14 by insert molding, for example.

  The fixed contacts 19 and 20 are not limited to a silver alloy, and may be composed of other metal materials such as a copper alloy and a gold alloy.

  As described above, the movable contact 18 and the fixed contacts 19 and 20 that are brought into and out of contact with each other are made of different materials having greatly different physical properties such as melting points, so that contact welding does not occur and reliability is improved. , Lifespan is greatly improved.

  Therefore, it is particularly suitable for severe applications where cutting failure due to contact welding is not allowed.

In the above embodiment, the movable contact 18 is made of a conductive plastic material and the fixed contacts 19 and 20 are made of a metal material. However, as another embodiment, the movable contact 18 is made of a metal material and the fixed contact 19 is made. , 20 may be made of a conductive plastic material.
In the above-described embodiment, the spring piece 14a is integrated with the movable piece 14. However, as another embodiment, the spring piece 14a may be formed of a separate member.

  The present invention is useful for micro switches, limit switches, and the like.

It is a partial longitudinal section front view of a switch concerning one embodiment of the present invention. FIG. 2 is an exploded perspective view of FIG. 1.

Explanation of symbols

1 Switch case 14 Movable piece 15, 16 Fixed piece 18 Movable contact 19, 20 Fixed contact

Claims (5)

In a contact structure comprising a fixed contact and a movable contact contacting and separating from the fixed contact,
One of the fixed contact and the movable contact is made of a conductive plastic material, and the other contact is made of a metal material.   The contact structure according to claim 1, wherein the metal material is a silver alloy. A movable piece having a movable contact at the free end, a receiving member connected to the terminal and supporting the base end of the movable piece in a swingable manner, and connected to another terminal and the free end of the movable piece A fixed piece provided with a fixed contact opposite to the movable piece, and a spring member that snaps the movable piece to bring the movable contact into and out of contact with the fixed contact,
One of the fixed contact and the movable contact is made of a conductive plastic material, and the other contact is made of a metal material.   The switch according to claim 3, wherein the spring member is formed integrally with the movable piece having a spring property.   The switch according to claim 3, wherein the one contact point made of the conductive plastic material is integrated with the fixed piece or the movable piece by insert molding.

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