JPS59226431A - High temperature fuse - 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 Field of Industrial Application The present invention relates to equipment and devices used under high temperature conditions;
For example, the present invention relates to a high-temperature fuse that is applied to detect abnormal temperatures inside a catalytic converter of an internal combustion engine.

Structure of the conventional example and its problems As shown in FIG. 1, the conventional high-temperature heater has a pipe-shaped fusible metal tube 2 having a space 1, a metal lead wire 3a,
3b is welded and fixed, and the tip of the metal lead wire 3a is grounded to the metal protection tube 4. After that, the metal protection tube 4 is filled with powder and a conventional electrical insulating material 5, the diameter of the metal protection tube 4 is reduced, and the opening of the metal protection tube 4 is The part was completely sealed with a sealing material 6.

This high-temperature fuse is used to blow out fusible metal pipes, but when used in high-temperature products such as internal combustion engines, which constantly expand and contract due to temperature rises and falls, the metal protection pipe may be damaged. There was a risk that the fusible metal tube with the grounded metal lead wire would break due to tensile and compressive stress caused by the temperature difference inside and outside the metal protection tube.

Purpose of the Invention The present invention provides a high-temperature housing that can maintain vibration resistance and mechanical strength even in locations where vibration is constantly applied at high temperatures and under usage conditions where the ambient temperature repeatedly rises and falls. Dechiru.

Structure of the Invention The present invention forms a fusible metal into a tensile spring shape when melted, welds and fixes metal lead wires from both ends at predetermined positions, and welds and seals the tip end lead wire to a metal protection tube and grounds it. 'It is a high temperature fuse filled with commercially insulating material. Therefore, in the present invention, the fusible metal wire in the shape of a tension spring, which is housed in a metal protection tube and grounded, is constantly subjected to vibrations, and even under severe usage conditions where expansion and contraction are repeated, the fusible metal wire in the shape of a tension spring expands and contracts. Because it is flexible, it is not affected by tensile or compressive stress due to temperature differences between the inside and outside of the metal protection tube, and can satisfy long-term high-temperature durability.

Description of examples FIG. 2 is a sectional view of the high temperature heater according to the present invention.

In this figure, the same numbers as in FIG. 1 indicate the same parts. The metal protection tube is made of stainless steel, Incoloy, Inconel, etc. 7 is a fusible metal wire in the shape of a tension spring, and uses not only noble metals but also general brazing materials such as silver solder and palladium solder, and alloys thereof. Metal lead wire sa, 3
b is welded and fixed at a predetermined position to the tension spring-shaped fusible metal wire 7 made of stainless steel, nickel, or nichrome wire Natkara by plasma welding, spot welding, or the like. In addition, there is magnesia oxide inside the metal protection tube 4.

It is made of a powdery hardening insulating material such as alumina and a powdery reducible insulating phase such as silicon tinide, and it is closely surrounding the fusible metal wire 7 in the shape of a tension spring, and when melted, the volume of the fusible metal wire 7 is smaller than the volume of the fusible metal wire 7. It is filled with an insulating material 6 having a large internal volume. Further, the sealing material 6 is made of a hand poxy resin and a glass adhesive material, and completely seals the opening of the metal protection tube 4, preventing the intrusion of oxygen and moisture, and preventing oxidation of the fusible metal wire 7. .

The figure (,) is a side view of the fusible metal wire 7, and the figure (b) is a side view of the fusible metal wire 7.
-1゛ sectional view. Moreover, FIG. 4 is a diagram showing only the fusible metal wire 7 and the metal lead wires 3a+3b.

FIG. 5 is a state diagram after the tension spring-shaped fusible metal wire 71 is fused due to an abnormal temperature rise, and the fusible metal wire 7'
is in an open state, cutting off electrical continuity between the metal lead wires 3a and 3b.

Effects of the Invention The present invention can withstand repeated durability over long periods of time by expanding and contracting a fusible metal wire in the form of a tension spring that is grounded within a metal protection tube, even under conditions of repeated expansion and contraction due to temperature rise and fall. Moreover, when the temperature rises to an abnormal level, the fusible metal wire is pulled at a predetermined temperature, and the fusible metal wire is melted into the inner volume of the strong electric insulator that is closely surrounding the spring-shaped fusible metal wire.
The surface tension of the fusible metal material can reliably fuse and create an open circuit. In addition, since the fusible metal part is grounded to the metal protection tube, the finished outside diameter of the metal protection tube can be made thinner, resulting in excellent thermal response.Also, since the fusible metal wire itself is in the shape of a tension spring, It is easy to work with and is very cost effective.

[Brief explanation of the drawing]

Figure 1 is a partial sectional view showing a conventional example, Figure 2 is the main diagram, and Figure 4 is a partial sectional view showing a conventional example.
The figure is an enlarged cross-sectional view of main parts of the molten metal wire and the metal lead wire, and FIG. 5 is a partial cross-sectional view of the heater according to the present invention after being fused. 3a, 3b...metal lead wire, 4...
Metal protection tube, 7...fusible metal wire.

Claims (1)

[Claims] A metal protection device that stores a fusible metal body in the shape of a tension spring, a pair of metal lead wires connected to both ends of the fusible metal body, and the fusible metal body and the metal leads via a powdery insulating material. A high temperature fuse having a tube, one of the metal lead wires being electrically connected to the metal protection tube, and the other metal lead wire being electrically insulated from the metal protection tube and led out.