JPS59211926A - Thermal reed 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] The present invention relates to a thermal reed switch.

Conventional thermal reed switches place a permanent magnet and a temperature-sensitive magnetic material such as temperature-sensitive ferrite near the outer periphery of the reed switch, and the magnetic flux density of the temperature-sensitive magnetic material rapidly decreases at a certain temperature as the temperature rises. Alternatively, the magnetic circuit can be completely constructed or deleted through the two reed pieces of the reed switch, making full use of the magnetic transformation temperature characteristics that rapidly increase as the temperature decreases, thereby closing and opening the contacts. was. However, in a thermal reed switch configured in this manner, the magnet and temperature-sensitive magnetic material are permanently disposed around the outer periphery of the reed switch, so it is difficult to achieve miniaturization, and furthermore, the large number of parts makes it difficult to produce at a low cost.

An object of the present invention is to provide a small and inexpensive thermal reed switch by providing the reed pieces of a self-holding type reed switch with the functions of the permanent magnet and temperature-sensitive magnetic material of a conventional thermal reed switch. .

The thermal reed switch according to the invention includes at least two reed pieces made by polymerizing a magnetic material having residual magnetic properties and a magnetic shunt alloy that reversibly changes into either a ferromagnetic material or a paramagnetic material at a magnetic transformation temperature. The main feature is that it is sealed through the insulating airtight container.

An embodiment of the invention will be described below with reference to one drawing.

FIG. 1 is a sectional view showing a first embodiment of a thermal reed switch according to the present invention, and FIG. 2 is a sectional view showing a second embodiment. First, in Fig. 1, numeral 1 is a reed piece made of a semi-hard or hard magnetic material with residual magnetic properties, and the opposing surfaces of the two reed pieces and the opposite side are each made of a remendal material, etc. Magnetic shunt alloy pieces 2 having special properties are tightly fixed and sealed in a glass tube 3. In FIG. A magnetic shunt alloy 5 is coated on the outer periphery of each core, and these are enclosed in a glass tube 6.

In both the first and second embodiments, at a temperature below the magnetic transformation point of the magnetic shunt alloy, an L-shaped magnetic circuit is formed between the semi-hard or hard magnetic lead pieces 1 or 40, and the contact portions are opened. When the magnetic shunt alloy reaches its magnetic transformation point due to temperature rise, the magnetic shunt alloy in the lead pieces changes from ferromagnetic to paramagnetic.

The magnetic circuit between the semi-hard or hard magnetic material disappears,
The contact portions are made of opposing semi-hard or hard magnetic materials or, in the second embodiment, are attracted to each other by the residual magnetism of the magnetic shunt alloy 5 and are closed. Even when the temperature is lowered from the temperature above the i-transformation point, the @gm alloy changes from paramagnetic to ferromagnetic at the magnetic transformation point, so that it becomes the semi-hard or hard magnetic material of lead piece 1 or lead piece 4 again. A magnetic circuit is formed between the lead pieces and the magnetic shunt alloy, and the contact portions of the reed pieces that do not lose their attractive force are opened. Note that the contact portion can be formed by disposing a noble metal (by electroplating or the like) on the tip of each lead piece.

As explained above, according to non-invention, reed switch σ
] By constructing the reed piece from a semi-hard or hard magnetic material and a magnetic shunt alloy, a small and inexpensive thermal reed switch can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of the invention, and FIG. 2 is a sectional view showing a second embodiment. 1.4...Lead piece, 2,5...Magnetic shunt alloy.

Claims (1)

[Claims] At least two magnets made of a magnetic material having residual magnetic properties and a magnetic shunt alloy that reversibly changes into either a ferromagnetic material or a paramagnetic material at a magnetic transformation temperature. A thermal reed switch characterized by a lead piece sealed through an insulating airtight container.