JPS61142433A - Temperature fuse sensor for high temperature - Google Patents

Abstract

PURPOSE:To achieve a quick burning out above the melting point with a high resistance to impact and vibration, by connecting one end of a heat resistant metal wire to the bottom surface of a heat resistant metal case through a meltable metal body while the other end thereof is connected to a coil spring in such a manner as to apply a tension stress thereon. CONSTITUTION:One end of a heat resistant metal wire 2 is connected to the bottom surface of a heat resistant metal case 7 through a meltable metal body 8 while one end of a coil spring 9a is connected to the other end of the metal wire 2 and the other end thereof 9a connected 11 sealed to a terminal 10 as stretched in such a manner that the tension stress thereof acts on the metal wire 2. With such an arrangement, when the temperature rises above the melting point or the solid phase temperature of the meltable metal body 8, a stress acts on the metal wire due to the spring 9a and hence, the bottom surface of the metal case 7 separates from the connection with the metal wire 2 quickly to form an electrically open circuit. This also permits the coil spring to absorb the stress due to thermal expansion, contraction and impact and vibration thereby preventing disconnection at the meltable metal body section.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-temperature fuse used for detecting abnormally high temperatures of 800'C or more in automobile exhaust gas purification devices used in vibration and thermal shock environments. It is related to sensors.

2. Description of the Related Art Hitherto, this type of high-temperature fuse sensor has had a structure as shown in FIG. 2, as shown in, for example, Japanese Patent Application Laid-open No. 143857/1983.

That is, heat-resistant metal wires 22L are provided at both ends of the fusible metal wire 1.

2b is connected, the fusible metal wire 1 is stored in the heat-resistant metal tube 6 with a gap 4 formed inside the insulating tube 3, and one of the heat-resistant metal wires 2b and the heat-resistant metal tube 6 are connected. Insulator 6 is filled and fixed inside heat-resistant metal tube 5.
It was.

Problems to be Solved by the Invention This conventional configuration has the following problems.

(1) Under the environment of high temperature-low temperature thermal shock at a temperature lower than the melting point of the fusible metal wire 1 and shock/vibration at high temperature, the fusible metal wire 1 is exposed to stress due to thermal expansion/contraction and shock/vibration. is concentrated, and the fusible metal wire 1 is disconnected.

(2) With respect to the outer diameter of the fusible metal wire 1, the length less than the total length of the fusible metal wire 1 excluding the connection part is called the effective length. ) is not sufficient, even if the temperature rises above the melting point of the fusible metal wire 1, the natural fusing properties of the fusible metal wire 1 will be extremely poor.

The present invention solves these problems by ensuring that the fusible metal wire does not break even under thermal shock, shock, and vibration environments at temperatures lower than the melting point of the fusible metal wire. The purpose is to quickly melt and cut the molten metal wire when the temperature rises above the melting point of the molten metal wire.

Means for Solving the Problem In order to solve this problem, the present invention connects one end of the heat-resistant metal wire to the bottom of the heat-resistant metal case via a fusible metal body, and connects the other end of the heat-resistant metal wire to the bottom of the heat-resistant metal case. One end of a coiled spring is connected to a heat-resistant metal wire in a state where tensile stress is applied by the coiled spring.

Function: Even in environments with thermal shock, shock, and vibration at temperatures lower than the melting point of the fusible metal, the coiled spring connected to the heat-resistant metal wire prevents thermal expansion, contraction, and shock.・Because the coiled spring absorbs the stress caused by vibration, there is no possibility of wire breakage in the fusible metal body.

In addition, when the temperature rises above the melting point or solidus temperature of the fusible metal body, tensile stress is applied to the heat-resistant metal wire by the coiled spring, so the connection between the bottom surface of the heat-resistant metal case and the heat-resistant metal wire quickly separate, creating an electrical open circuit.

Embodiment FIG. 1 is a sectional view of a high temperature temperature fuse sensor according to an embodiment of the present invention. In FIG. 1, one end of a heat-resistant metal wire 2 is connected to the bottom surface of a heat-resistant metal case 7 via a fusible metal body 8, and one end of a coiled spring 91L is connected to the other end of the heat-resistant metal wire 2. The other end of the spring 91L is sealed and connected 11 to the terminal 1o in a stretched state so that the tensile stress of the coiled spring 9a acts on the heat-resistant metal wire 2.

Further, an insulating tube 121L is arranged around the heat-resistant metal wire 2, and an insulating tube 12b is arranged around the coiled spring 9a to maintain insulation. By fixing the plate 14, the coiled spring 9
The insulating tube 12 & is fixed under pressure by b. Further, the opening end of the heat-resistant metal case is sealed with a heat-resistant sealing material 16.

Effects of the Invention As described above, according to the present invention, one end of a heat-resistant metal wire is connected to the bottom surface of a heat-resistant metal case via a fusible metal body, and one end of a coiled spring is connected to the other end of the heat-resistant metal wire. If the temperature rises above the melting point or solidus temperature of the fusible metal body by connecting the metal wire with tensile stress applied by the coiled spring, the tensile stress due to the coiled spring will act on the heat-resistant metal wire. Therefore, the connection between the bottom of the heat-resistant metal case and the heat-resistant metal wire quickly separates, resulting in an electrical open circuit.

In addition, even in environments with thermal shock, shock, and vibration at temperatures lower than the melting point of fusible metal objects, by connecting a coiled spring to a heat-resistant metal wire, stress caused by thermal expansion, contraction, shock, and vibration can be reduced. Since the coiled spring absorbs this, there is no possibility of wire breakage at the fusible metal body, resulting in excellent reliability.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a high temperature temperature fuse sensor according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional high temperature temperature fuse sensor. 7... Heat-resistant metal case, 8... Fusible metal body, 2... Heat-resistant metal wire, 9 &... Coiled knot.

Claims (1)

[Claims] One end of a heat-resistant metal wire is connected to the bottom of a heat-resistant metal case via a fusible metal body, one end of a coiled spring is connected to the other end of the heat-resistant metal wire, and the tensile stress caused by the coiled spring is applied to the heat-resistant metal wire. A high-temperature thermal fuse sensor that features a structure that creates an electrically closed circuit by connecting in a high-temperature state.