JPH0570247B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] In conventional reed switches, rhodium is deposited on the contact portion of an elastic body made of magnetic material, but if the rhodium layer is thin, the life of the contact will be short and if it is thick, the manufacturing cost will increase. It gets expensive. Therefore, another inexpensive metal was deposited under the thin rhodium layer in order to extend the life of the contact and reduce manufacturing costs.

[Industrial application field]

The present invention relates to a reed switch that can extend the life of contacts and reduce manufacturing costs.

A reed switch in which a reed piece that serves as both a magnetic path and a contact point is sealed in a glass tube together with an inert gas is highly reliable because it is not affected by dust, harmful gases, moisture, etc. in the atmosphere. Since the movable weight and distance traveled during contact operation are very small, operation time and recovery time are faster than electromagnetic relay contacts. It also has many advantages, such as making it possible to reduce the size and weight of devices used as opening/closing elements.

However, in order to stabilize the contact resistance and give sharp breaking characteristics, rhodium is coated on the contact area, and if the rhodium layer is made thinner to reduce manufacturing costs, it will wear out in the depth direction, which is unique to rhodium. Therefore, the life of the contact is short, and if the rhodium layer is made thicker in order to extend the life of the contact, the manufacturing cost increases.

Therefore, it is desired to realize a reed switch that can obtain stable contact resistance and sharp opening characteristics, and can also realize a longer contact life and lower cost.

[Conventional technology]

FIG. 4 is a side sectional view showing a conventional reed switch.

In a conventional reed switch, a pair of reed pieces 2 are inserted from both ends of a glass tube 1, as shown in FIG.
The contact portion 21 of the lead piece 2 is sealed in the glass tube 1 together with an inert gas. At least the contact portions 21 of the pair of lead pieces 2 overlap, and the flat contact portions 21 face each other with a gap 3 interposed therebetween.

The lead piece 2 is made of a magnetic material and serves as both a magnetic path and a contact point. Therefore, when a magnetic flux is applied to the reed switch from the outside, the magnetic flux flows through the reed piece 2 and an attractive force is generated in the contact portion 21, and the contact portions 21 facing each other through the gap 3 are attracted to each other. The contacts become conductive. Furthermore, when the magnetic flux applied from the outside is removed, the attractive force in the contact portion 21 disappears, and the contact becomes open.

Note that the lead piece 2 formed only of magnetic material has a large contact resistance and is unstable even when the contacts are in a conductive state. Further, sharp opening characteristics cannot be obtained when transitioning to the open state. Therefore, a shoulder 22 made of rhodium is attached to the surface of the contact portion 21.

[Problem that the invention seeks to solve]

However, if the rhodium layer is made thinner to reduce manufacturing costs, the life of the contact will be shortened due to the depthwise wear of the rhodium properties, and if the rhodium layer is thickened to extend the life of the contact, the manufacturing cost will be reduced. There was a problem with the price being high.

[Means for solving problems]

FIG. 1 is a side sectional view showing one embodiment of the reed switch according to the present invention, and the same objects are represented by the same symbols throughout the figures.

The above-mentioned problem arises in a reed switch in which a pair of lead pieces are inserted into a glass tube so that the contact points overlap, and the lead piece 4 is made of an elastic body made of a magnetic material. The nickel layer 43 is only on the contact portion 42 of
This problem is solved by the reed switch of the present invention, in which a rhodium layer 45 is deposited after a copper layer 44 and a copper layer 44 are deposited and a contact is formed after a diffusion treatment.

[Effect]

In Fig. 1, a nickel layer and a copper layer are laminated on the contact portion of a lead piece made of an elastic body made of magnetic material, and a layer is deposited on top of the layer by diffusion treatment and forming a contact point. Even if the rhodium layer 45 is thin, the abrasion characteristic of rhodium in the depth direction is diffused to the surroundings, reducing local abrasion. As a result, it is possible to construct a reed switch that has stable contact resistance and sharp release characteristics, and that can simultaneously achieve long life and low cost.

〔Example〕

The lead piece of the above embodiment will be explained in detail below with reference to the accompanying drawings. FIG. 2 is a diagram showing a first lead piece forming method, and FIG. 3 is a diagram showing a second lead piece forming method.

The lead piece is formed by a first method in which a wire-like elastic body 41 made of a magnetic material as shown in FIG. A second method involves applying a nickel layer 43 and a copper layer 44 to a plate-shaped elastic body 41 made of a magnetic material as shown in FIG. 3, performing a diffusion treatment, and then molding individual lead pieces. There is a lead piece formed by.

In Fig. 2, the elastic body 41 is made of 52 alloy (Ni50
The contact portion 42 of the lead piece 4 is a wire such as a round wire or a square wire made of a magnetic material such as ~52% by weight, the remainder Fe), and is formed by shaping an elastic body 41 into a predetermined shape.
Nickel layer 43 of 2μm or more due to glare
After depositing a copper layer 44 of 2 μm or more and performing a diffusion process, an extremely thin rhodium layer 45 of 3 μm or less is plated thereon.

In FIG. 3, the lead piece 4 is formed by plating a plate-shaped elastic body 41 made of a magnetic material such as 52 alloy with nickel and copper in layers, performing a diffusion treatment, and then punching it out using a press or the like. Nickel layer 43
and a copper layer 44 are simultaneously molded, and an extremely thin rhodium layer 45 of 3 μm or less is plated thereon. Note that, instead of plating the nickel layer 43 and the copper layer 44, the same result can be obtained by laminating a nickel foil and a copper foil and performing a diffusion treatment.

By using the reed piece 4 having the above structure, it is possible to construct a reed switch which has stable contact resistance and sharp separation characteristics, and which can simultaneously achieve long life and low cost.

Further, the contact portion 41 on which the nickel layer 42 and the copper layer 43 are deposited and diffused has a sharp separation characteristic, and the stability of the contact resistance is lower than that of rhodium, but higher than that of 52 alloy. Therefore, in reed switches aimed at controlling relatively high-level currents in which "variation" in contact resistance is not a big problem, it is possible to extend the life of a reed switch by using the reed piece 4 in a state before being plated with a rhodium layer. It is possible to achieve lower prices at the same time.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a reed switch which can obtain stable contact resistance and sharp opening characteristics, has a longer contact life, and can realize lower costs.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of the reed switch according to the present invention, FIG. 2 is a view showing a first lead piece forming method, and FIG. 3 is a view showing a second lead piece forming method. FIG. 4 is a side sectional view showing a conventional reed switch. In the figure, 1 is a glass tube, 3 is a gap, 4 is a lead piece, 41
4 is an elastic body, 42 is a contact portion, 43 is a nickel layer, 4
4 represents a copper layer, and 45 represents a rhodium layer.

Claims (1)

[Scope of Claims] 1. A reed switch in which a pair of reed pieces are inserted into a glass tube so that the contact portions overlap and are sealed in the glass tube together with an inert gas, the reed switch being made of an elastic body made of a magnetic material. A nickel layer 43 and a copper layer 4 are formed only on the contact portion 42 of the lead piece 4.
4. A reed switch characterized in that a rhodium layer 45 is deposited after lamination of 4 and subjected to a diffusion treatment to form a contact point.