JPS6070611A - Lead switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a non-self-holding reed switch, and more particularly to a reed switch using a reed piece made of a Co--Pe based ferromagnetic material with low electrical resistivity.

(b) Background of the technology Conventional non-self-holding reed switches are generally used in fields that handle small currents of about 0.5A, and the material forming the reed pieces has characteristics such as magnetic material rather than electrical resistivity. That is, materials have been selected by focusing on magnetic flux density, coercive force, coefficient of thermal expansion, tensile strength, etc.

However, if we try to make a reed switch that can flow a large current of 5A or more, which is the current value required for temperature-sensitive reed switches and motorronics devices in the future, the reed switch will not work at all due to the large amount of heat generated by the reed piece itself. However, the problem arises that the shape of the reed switch must be made several times larger than usual, and the material that forms the reed piece must have the characteristics of a magnetic material, such as magnetic flux density, coercive force, and heat. It is desired to develop a ferromagnetic material that has excellent expansion coefficient, tensile strength, etc., and low electrical resistivity.

(C) Prior art and problems FIG. 1 is a sectional view of a reed switch. A normal reed switch has a pair of reed pieces 2.3 from both ends of the glass tube l.
is inserted and sealed in an inert gas atmosphere.

When the excitation coil 4 disposed outside the glass tube 1 is energized, the magnetic flux passing through both reed pieces 2.3 closes the gap 5 between the overlapping contact portions of the reed pieces, turning on the switch. Next, when the excitation coil 4 is de-energized, the magnetic attraction force of the contact gap 5 disappears, the contact gap 5 opens, and the switch is turned off.

Conventionally, 52 alloy has been used as the material for forming the lead piece 2.3 because it has excellent properties as a magnetic material, such as magnetic flux density, coercive force, coefficient of thermal expansion, and tensile strength. Fe (10-18%
)-Co(remainder) alloy ferromagnetic material is used. The Fe
(10-18%) -Co (remainder) Properties of the alloy are shown in Table 1
It is as follows.

That is, although it is slightly inferior to 52 alloy in terms of magnetic flux density and coercive force, its electrical resistivity is much lower than that of 5270 alloy, and its thermal expansion coefficient is 117.
It is about the same as 5±2.5×10-'/"C.

However, although it is not listed in Table 1, 10=18Fe-C.

The alloy has a problem in the sealing strength of the lead pieces 2 and 3. That is, in a low-temperature tensile strength test in which the glass tube 1 was fixed in a low-temperature atmosphere of -55°C and a load of 2 kg/72 br was applied to the lead piece 2 or 3, the leak failure was 0% for 5270I but 10-18Fe. -Approximately 10 for Co alloy
It has been confirmed that 0% causes leak failure.

Td) Purpose of the Invention The purpose of the present invention is to improve the properties of a magnetic material, namely magnetic flux density,
We provide a reed switch that has excellent holding power, coefficient of thermal expansion, tensile strength, etc. to the extent that it does not pose a problem in practical use, and that the reed piece is made of a ferromagnetic material with low electrical resistivity, which solves the above-mentioned problem. It's about doing.

(el Structure of the invention and this purpose is Fe (8-12%), Ni (3-
This is achieved by enclosing a lead piece made of a ferromagnetic material of 6%) and Go (remainder) alloy in an enclosure in an inert gas.

<r+ Embodiments of the Invention Next, examples will explain how the reed switch according to the invention is actually implemented. Figure 2 shows Fe (8 to 12%), Ni (3 to 6%), and Co according to the present invention.
It shows the relationship between the Ni content in the ferromagnetic material of the (remaining) alloy, the coercive force Hc, and the leak failure rate.

In the figure, when the old content is 0%, the leak defect rate is almost 1.
However, when the Ni content becomes 3% or more, the leak defect rate decreases to 0%.

-Blade retention force 1 (c increases as the Ni content increases, but the retention force Hc is allowed up to 50e in non-self-retaining type reed sui-nochi, and when the Ni content is 6
% or less, there is no problem in practice.

Also, the thermal expansion coefficient is about 126±3X10-'/”C, and lθ
~123±3X10-'/”C of 18Fe-Co alloy
Although it is slightly larger than , this is not a problem in practice.

Furthermore, other properties are almost equivalent to those of the 10-18Fe-Co alloy.

Table 2 summarizes the above characteristics.

Table 2 That is, Pe (8~, 12%), N1 (3~, 12%) according to the present invention
6%), Co (residue) alloy is a ferromagnetic material that has a much lower electrical resistivity than 52 alloy and has the same sealing strength.

Effects of the Invention As described above, according to the present invention, the properties as a magnetic material, that is, magnetic flux density, coercive force, coefficient of thermal expansion, tensile strength, etc. are excellent to the extent that there is no problem in practical use, and the electrical resistance is excellent. It is possible to provide a reed switch in which the reed pieces are formed of a ferromagnetic material with a low magnetic flux and have excellent sealing strength.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a reed switch, and FIG. 2 is a diagram showing the relationship between Ni content, coercive force Hc, and leak failure rate in the ferromagnetic material of the present invention. In the figure, 1 is a glass tube, 2 and 3 are a pair of lead pieces, 4 is an excitation coil, and 5 is a gap between contact portions.

Claims (1)

[Claims] A lead piece made of a ferromagnetic material of an alloy of Fe (8 to 12%), N1 (3 to 6%), and Co (the balance) is sealed in an enclosure in an inert gas.