JPH03167718A - Lead switch - Google Patents

Abstract

PURPOSE:To obtain a lead switch having the increased current capacity and wide usage with high reliability by composing contacts with Cr and Cu and/or Ag and making the mean diameter of Cr specified at a value less than 74mum with the specified composition of Cr. CONSTITUTION:Contacts 7, 8 are made of the alloy, which is composed of Cr and Cu and/or Ag and the mean diameter of Cr is specified at a value less than 74mum and the composition of Cr is specified at 20-80wt.%. The contact surface is highly hardened with the fine distribution effect of Cr to prevent the sticking by specifying the mean diameter of Cr less than 74mum. Since the thinnest (A order) film is formed on the surface of Cr particle where Cr is exposed with the active metal, the weldingproof ability is improved and sticking is prevented. A lead switch having the increased current capacity with wide usage can be thereby obtained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a reed switch used in medium-load and heavy-load circuits, and particularly to a reed switch that prevents the occurrence of the stick phenomenon and improves the current capacity. This relates to improvements in the number of contact points.

(Prior art) As shown in Fig. 2, a conventionally commonly used reed switch has an inert gas 2 sealed inside a glass container l, and a pair of contacts 3 and 4 that can be freely connected and separated. A pair of leads 5 and 6, each provided with a lead 5 and 6, are housed with appropriate gaps and overlaps.

In this configuration, the contacts 3 and 4 are arranged facing each other as shown in FIG.
, 6 by any joining method such as cold welding, brazing, or spot welding.

In addition, such contacts 3 and 4 are formed by plating or cladding the tips of the leads 5 and 6 with Au, Ag, Rh, or Ru, which can be selected as appropriate depending on the intended use of the reed switch. has been done.

In this way, the materials for the contacts 3 and 4 include Au, Ag, and R.
The reason why precious metals such as H, Ru, etc. are used is because the contact pressure of reed switches is weaker than that of wire spring relays, so a material with low contact resistance is required even at low contact pressure.

(Problems to be Solved by the Invention) However, the above-mentioned materials are expensive and have problems in that they cause adhesion, melting, welding, etc., so their range of application is limited in terms of current capacity. Sisters. It was not possible to fully utilize the original characteristics of the reed switch, which is its small size and light weight.

SUMMARY OF THE INVENTION Therefore, an object of the present invention was to eliminate the above-mentioned conventional drawbacks, and particularly to provide a reed switch with increased current capacity, high reliability, and an expanded range of use.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a reed switch in which a pair of contacts that can be freely connected and separated are arranged via leads in a glass container filled with an inert gas. Consisting of Cr, Cu and/or Ag, and the average particle size of Cr is 74 or less, and C
It is formed from an alloy in which the composition of r is 20 to 80 wt%.

(Function) Since the average particle size of Cr is 74 mm or less, the contact surface becomes highly hard due to the fine dispersion effect of Cr, which is preferable for preventing sticking. or. Since Cr is an active metal, an ultra-thin (λ order) film is formed on the exposed Cr particle surface, which has excellent welding resistance and is effective in preventing sticking, increasing current capacity and making it suitable for medium to heavy load circuits. The scope of application can be expanded as a result.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is an enlarged view showing a contact portion of an embodiment of the present invention.

In the second construction drawing, contacts 7 and 8 are provided at the tip portions of each of the leads 5 and 6 so as to be able to freely come into contact and separate from each other. The present invention is characterized by the contacts 7 and 8, and first, a method for manufacturing the materials of the contacts 7 and 8 will be explained.

Methods for manufacturing the materials for the contacts 7 and 8 include (1) liquid phase sintering;
■Solid phase sintering method and (3) melting method.

ω Liquid phase sintering method First, a predetermined amount of Cr is prepared and mixed.

Thereafter, the powder compact is obtained by pressure molding. Subsequently, this powder compact is pre-sintered at a predetermined temperature, e.g. 1100° C.XIHr, in a hydrogen atmosphere with a dew point of -50° C. or less or a degree of vacuum of 1.3×10 −′ Pa or less, to obtain a pre-sintered compact. .

Next, a predetermined amount of Cu is added into the remaining pores of this pre-sintered body.
Infiltrate under the conditions of 50℃ x IHr. A Cu-Cr alloy is obtained. This infiltration is primarily carried out in hydrogen, but it is also possible in vacuum.

In addition, the above-mentioned Cu. The method for producing Cr-based alloys such as Ag or Ag-Cu alloys is almost the same.

(2) Solid phase sintering method First, predetermined amounts of Cu and Cr powders are prepared and mixed. Thereafter, the powder compact is obtained by pressure molding. Subsequently, this powder or shaped body is sintered at a predetermined temperature, e.g., 950° C. obtain.

Next, this sintered body is press-molded to eliminate any remaining pores.

The above-described sintering and post-sintering pressurization are repeated several times to obtain a Cu--Cr alloy having a theoretical density of 96% or more.

The method for producing a Cr-based alloy in which Cu is replaced with Ag or an Ag-Cu alloy is almost the same, but the sintering temperature is 850°C for Ag and 6°C for the Ag-Cu alloy.
It is 00℃.

■Dissolution method First, a predetermined amount of granular C' and Cu are prepared and mixed. Thereafter, the mixture is incorporated into a raw material feeder in the furnace. This mixture is then dissolved in an inert gas under reduced pressure, e.g.
Under an Ar atmosphere with a pressure of
Obtain a Cr alloy.

In addition, the above-mentioned Cu. A method for producing Cr-based alloys as Ag or Ag-Cu alloys is also provided. Almost the same. Further, the melting by electron beam was almost the same, but in this case, the degree of vacuum was 1.5×10 −4 Pa.

The Cr-based alloy produced by each of the above-mentioned methods was machined into a predetermined contact shape, bonded to the tip of the lead 5.6, and housed in a glass container 1 filled with an inert gas 2. I made a reed switch.

Next, a method for measuring and evaluating switching characteristics will be explained.

A plate-shaped contact piece measuring 3 mm vertically, 3 mm wide, and 1 mm thick is fixed to the tip of the reed with silver brazing, and is housed in a glass tube filled with inert gas as shown in Figure 2 to create a reed switch. Manufactured. DCIOOV-500mA circuit 20X
The number of times sticking occurred when opening and closing 10' times was determined. In addition, 20 reed switches were manufactured for each contact point, and the results are shown in terms of the variation width (minimum and maximum) from the opening/closing test. The occurrence of adhesion was determined by a delay in the opening time of the contact, and as a criterion, a number of times of adhesion of 50 or more times was considered defective.

Changes in the contact resistance of the surveillance board were measured using the west terminal voltage drop method for the reed switch that underwent the opening/closing test above. The current applied was DC12V-10i1A. The measurement results are
Shown as the variation width (minimum and maximum) for 20 reed switches. Moreover, as a judgment criterion, 2Ω or more was determined to be defective.

1 to 3, Comparative Examples 1 and 2 In order to investigate the switching characteristics, reed switches were manufactured using different contact materials. That is, the average particle diameter of Cr particles is 1-, and the amount of Cr is 20. 50, 80 wt% (
Examples 1 to 3) and those with a Cr content of 10,909 t% (Comparative Examples 1 and 2).

Table 1 shows these switching characteristics. According to this result,
When the Cr content was 90 wt% (Comparative Example-2), there was no significant difference in the number of adhesives from each Example, but the contact resistance was significantly inferior. This is considered to be because the large amount of Cr increases the probability of contact between Cr, increasing the contact resistance and deteriorating the switching characteristics.

direction. When the Cr content was 10 wt% (Comparative Example-1), there was no significant difference in contact resistance from each of the Examples, but an increase in the number of adhesion was observed. This is considered to be because the small amount of Cr increases the contact between Cu and increases the number of diameters where adhesion occurs, resulting in a decrease in opening and closing characteristics.

From the above points, it was found that a Cr amount of 20 to 80 vt% is effective.

-4 5, -3 Reed switches were manufactured by changing the contact materials in the same manner as in the above-mentioned Examples and Comparative Examples. That is. Cr amount is 501It%
and the average particle size of Cr particles was 0.5- (Example-4), 74 m (Example-5), 210-
It is a closed one (Comparative Example-3).

Table 1 shows these switching characteristics. As a result, fine Cr
Regarding the opening/closing characteristics due to the dispersion effect of particles, when the average particle diameter of Cr particles was 210, m (Comparative Example-3), there was variation among samples in the number of adhesives, and there was also variation in contact resistance. Stable characteristics could not be obtained. On the other hand, when the average particle diameter of the Cr particles was 74 μs (Example-5), the number of adhesion was small, and the contact resistance was also low and stable characteristics were obtained.

From this result, the optimal average particle size of Cr particles is 0.51 (
It was found that Example 4) exhibited the best properties in terms of adhesive number and contact resistance.

From the above points, the average particle size of Cr particles is limited to 74 μs or less.

Examples 6 and 7 In the above-mentioned Examples and Comparative Examples, contact materials were manufactured by solid phase sintering, but in the case of liquid phase sintering (Example 6) and arc melting (Example 7) As shown in Table 1, the same opening/closing characteristics as those of the above-mentioned Examples were also exhibited. Here, in both Examples, the amount of Cr was 50 wt%, and the average particle size of the Cr particles was 1 p.

It should be noted that the same effect as arc melting was obtained with electron beam melting, and it is clear that a water-cooled copper crucible with a fast cooling rate can be used to manufacture contacts by the melting method.

The above-mentioned Examples 1 to 7 and Comparative Examples 1 to 4 showed examples in which Cu was used as a component of the contact material, but the present invention also uses other highly conductive materials, For example, Ag (Example-8) or Ag
- In the case of the Cu alloy (Example 9), as shown in Table 1, the same opening and closing characteristics as in each of the above-mentioned Examples were exhibited, and it was found to be effective.

(Hereinafter, in the margins) [Effects of the Invention] As explained above, according to the present invention, since the contacts are made of a contact material that is resistant to adhesion and has low contact resistance, it is possible to increase the current capacity and expand the range of use. Accordingly, it is possible to provide a reed switch with the following advantages.

[Brief explanation of the drawing]

Figure 1 is an enlarged view of the contact part of the reed switch of the present invention.
Figure 2 is a vertical cross-sectional view showing the configuration of a conventional reed switch.
FIG. 3 is an enlarged view of the contact portion of a conventional reed switch.

Claims (1)

[Claims] In a reed switch, a pair of contacts that can be freely connected and separated are arranged through leads in a glass container filled with an inert gas, and the contacts are made of Cr, Cu, and/or A.
g, and the average particle size of Cr is 74 μm or less, and Cr
A reed switch characterized in that it is formed from an alloy having a composition of 20 to 80 wt%.