JPS63276834A - Contact point structure of electromagnetic relay - Google Patents

Abstract

PURPOSE:To secure high contacting property and prevent occurrence of adhesion phenomenon by composing surface material provided on contact base material of a layer of gold and palladium alloy provided on the inner side and a layer of gold plating provided on the layer of gold and palladium. CONSTITUTION:A fixed contact 2 is installed at a fixed contacting piece 1 composed of an iron piece by caulking. The contact 2 is composed of contact base material 3 composed of silver and copper alloy, a layer of gold and palladium alloy 4 applied on the base material 3 and including palladium at the rate of 3-5%, and a layer of gold plating 5 provided along the whole periphery of the alloy layer 4 and having thickness of 1-3mu. At a movable contact piece 6 composed of a flat spring is installed a movable contact 7 composed of contact base material, a layer of gold and palladium alloy and a layer of gold plating as in the contact 2. High contacting property is thus second, while occurrence of adhesion phenomenon can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a contact structure used in an electromagnetic relay for switching small loads.

(Prior art and its problems) FIG. 4 is a side view of a contact of a general electromagnetic relay. In FIG. 4, numeral 101 is a movable contact piece, and 102 is a fixed contact piece. Each contact piece lO! , 102 are attached with contacts 101a and 102a.

Among such contact structures, in the case of those used for electromagnetic relays for switching minute loads, for example, both the contacts 101a and 102a are connected to the contact base material 103.10.
4 and the surface material 1 of a gold/silver alloy composition with a silver content of 10% formed on the surfaces of the contact base materials 103 and 104.
05.106 is used.

When the above-mentioned gold/silver alloy is used as the surface material 105 and 106, high contact properties can be obtained between the contacts 101a and 102a, so that the conduction of a minute current when the contacts are closed is ensured. There are advantages.

However, while the above-mentioned contact structure composed of gold or silver-gold as the surface material has the advantage of being able to maintain high contact performance, it is difficult to use, for example, in a closed type electromagnetic relay with a normally closed contact structure. However, when ultrasonic cleaning is performed with the electromagnetic relay attached to a printed circuit board, both contacts tend to stick together, which is a so-called sticking phenomenon.

When such a phenomenon of adhesion between the contacts occurs, even if an attempt is made to separate the two contacts by energizing the electromagnet in the electromagnetic relay, the contacts will not be able to be separated smoothly with the specified energizing power; Even if the adhesive contacts are separated by increasing the contact area, the surface of the contacts will be damaged after separation, which will impede the reliability of the electromagnetic relay's subsequent operation.

(Object of the Invention) The present invention has been made to solve the above problems, and while it is possible to ensure high contact properties of the contacts, it also prevents the above-mentioned adhesiveness between the contacts by ultrasonic cleaning etc. The purpose is to prevent the phenomenon from occurring.

(Structure and Effects of the Invention) Contacts of the electromagnetic relay of the present invention for achieving the above object (
It consists of a contact base material and a surface material provided on the contact ring, and the surface material includes a gold/palladium alloy layer provided on the inside, and a gold plating provided on the gold/palladium layer. It is composed of layers.

According to the above structure, since the gold plating layer structure constitutes the outermost surface of the contact, high contactability of the contact can be ensured.

In addition, since the gold/palladium alloy layer is located below the gold plating layer, the contact surface hardness is higher than that of conventional contact structures where the surface material is simply a gold/silver alloy layer. (Thus, even if ultrasonic cleaning treatment or the like is performed, the adhesive phenomenon of the contacts will not occur.

Therefore, according to the contact structure of the present invention, high contactability of the contacts can be ensured, and an electromagnetic relay can be subjected to ultrasonic cleaning treatment, etc., without causing contact stickiness. This makes it possible to make the separation movement of the contacts smoother and to effectively prevent damage to the contact surfaces, resulting in a highly reliable contact structure. .

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 are diagrams showing the contact structure of an electromagnetic relay according to an embodiment of the present invention. FIG. 1 is a side view of the contact structure, and FIG. 2 is a partially cutaway perspective view of the contact structure. be.

In these figures, reference numeral 1 denotes a fixed contact piece made of an iron piece, and 2 denotes a fixed contact attached to the fixed contact piece 1 by staking.

The fixed contact 2 includes a contact base material 3 made of a silver-copper alloy,
A gold-palladium alloy layer 4 stuck on the contact base material 3 and having a palladium content of 3 to 5%, and a layer 1 provided on the entire outer periphery from above the gold-palladium alloy layer 4.
It is composed of a gold plating layer 5 having a thickness of ~3μ.

6 is a movable contact piece made of a spring plate. A movable contact 7 is attached to the movable contact piece 6, which, like the fixed contact 2, is composed of a contact base material, a gold-palladium alloy layer, and a gold plating layer.

The contact structure of this embodiment is used as a normally closed contact mechanism of an electromagnetic relay 8, as shown in FIG. In FIG. 3, 9 is a base, 10 is a yoke, 11 is an electromagnet, 12 is a movable body, 13 is a card, and 14 is a sealing case.

In the electromagnetic 1 m electric appliance 8 having such a structure, when the electromagnet 11 is not energized, the spring force of the movable contact piece 6 causes
The movable contact 7 and the fixed contact 2 are in contact with each other. The contact is closed in this contact state (normally closed state).

Next, when the electromagnet 11 is excited and the movable body 12 is attracted by the electromagnet 11 and rotates about its fulcrum in the direction of the arrow (clockwise in the drawing), the movable contact piece 6 is pushed by the card 13. As a result, the movable contact 7 is moved a distance M from the fixed contact 2.

Ultrasonic cleaning of the electromagnetic relay 8 having such a structure and operation is performed with the movable contact 7 and the fixed contact 2 in contact with each other.

Table 1 below shows samples of 20 electromagnetic relays using the contact structure of the example and 20 samples using the contact structure of the conventional example.
The adhesion state of the contacts was compared and measured before and after ultrasonic cleaning with samples of electromagnetic relays. However, in Table 1, the adhesion state is expressed by the voltage value applied to the electromagnetic coil required to separate the movable contact 7 and the fixed contact 2.

Further, the cleaning conditions such as cleaning frequency and ultrasonic output in Table 1 are as follows.

Cleaning frequency: 36-42KHz Ultrasonic output: 600 Wsax Cleaning tank area: 330 aoa x 400 mm Watt density: 0
, 455 W/as Cleaning liquid Freon cleaning time 5 minutes (blank below) Table 1 As is clear from Table 1, for electromagnetic relays using conventional contact structures, in many samples, the The increase in applied voltage after cleaning is large. this is,
This shows that a considerably strong adhesion state has occurred between the movable contact 7 and the fixed contact 2.

In contrast, in the electromagnetic relay using the contact structure of the present invention, the increase in applied voltage is zero or small in most samples. This indicates that there was almost no occurrence of an adhesive state between the movable contact 7 and the fixed contact 2.

Table 2 shows the resistance between the contacts 2°7 (inter-contact resistance) CR (+aΩ) of the present invention and the conventional example. As is clear from Table 2, there is almost no difference in the resistance OR between the contacts. This means that in the present invention, both the movable contact 7 and the fixed contact 2 have a gold-palladium alloy layer 4 on the inside of the surface material.
The structure is such that the gold plating layer 5 is provided on top of the gold plating layer 5, and therefore, it is possible to ensure high contact properties comparable to those of the conventional example. (Left below) Table 2

[Brief explanation of the drawing]

1 to 3 relate to the present invention; FIG. 1 is a side view of the contact structure of the embodiment, FIG. 2 is a partially cutaway perspective view of a fixed contact, and FIG. 3 is the contact structure of the embodiment. It is a side sectional view of the electromagnetic relay used. FIG. 4 is a perspective view of a conventional contact structure. In the figure, l... fixed contact piece, 2... fixed contact, 3...
- Contact base material, 4... First surface material, 5... Second surface material, 6... Movable contact piece, 7... Movable contact.

Claims (2)

[Claims] (1) Consisting of a contact base material and a surface material provided on the contact base material, the surface material is provided on a gold/palladium alloy layer located inside and on the gold/palladium layer. A contact structure of an electromagnetic relay characterized by being composed of a gold-plated layer. (2) The contact of the electromagnetic relay according to claim 1, wherein the gold-palladium alloy layer has a palladium content of 3 to 5%, and the gold plating layer is formed to have a thickness of 1 to 3 μm. structure.