JPS6114113Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a temperature fuse using a fusible alloy.

Electrical equipment has come to have built-in temperature rise prevention devices for safety reasons. This temperature rise prevention device includes a resetting type such as a bimetal switch, and a non-resetting type temperature fuse using a temperature-sensitive pellet made of a fusible alloy or an insulating organic chemical substance. The former type, which can be reset, returns to its original state once the ambient temperature drops, so it is convenient for controlling the temperature below a predetermined value, but it is not recommended as a final safety device. If you think about it, even if it is activated and opens the circuit due to an abnormal rise in ambient temperature, it will close the circuit again when the ambient temperature drops, so as long as the cause of the abnormal temperature rise is not removed, the circuit will repeat the opening and closing operation, and eventually This is dangerous as it may cause contact welding. Therefore, temperature control is generally performed using a resettable switch such as a bimetallic switch, and a dual safety mechanism using a non-resettable temperature fuse is adopted as the final safety device.

Among these types of temperature fuses, those that use temperature-sensitive pellets made of insulating organic chemicals generally have a complex structure and are expensive, while those that use fusible alloys generally have a simple structure and are inexpensive. . There is a structure using the latter fusible alloy as shown in FIG. Reference numerals 1 and 2 denote a pair of lead wires, and a fusible alloy 3 is fixed between the opposite ends of the lead wires. If necessary, a flux 4 is applied to the circumferential surface of the fusible alloy 3, and the fusible alloy 3 is coated with glass or ceramic. , is inserted into an insulating cylinder 5 made of resin or the like, and the openings at both ends of the insulating cylinder 5 and the lead wires 1 and 2 are sealed with a sealing resin 6 such as epoxy resin.
It is sealed by 7.

In the above configuration, when the ambient temperature exceeds the melting point of the fusible alloy 3, the fusible alloy 3 melts and the flux 4
The melted fusible alloy 3 is spherically fused to the tips of the lead wires 1 and 2 due to the action of the lead wires 1 and 2.
The circuit becomes non-conductive and the circuit is opened. When the ambient temperature decreases, the fusible alloy that has been fused to the tips of the lead wires 1 and 2 solidifies and becomes fixed, so that the circuit remains open.

By the way, in the conventional temperature fuse, the tips of the lead wires 1 and 2 are flat surfaces as in the above structure, so if the lead wires 1 and 2 and the fusible alloy 3 are not firmly fixed, transportation may be difficult. The fusible alloy 3 may fall off from the lead wires 1 and 2 during use or during use, and the fusible alloy 3 may fall off due to an abnormal rise in ambient temperature.
When the lead wires 1 and 2 were melted, the strength of the welding of the melted fusible alloy to the tips of the lead wires 1 and 2 was weak, and they sometimes separated due to vibration or impact.

Therefore, in order to solve such problems,
For example, in Japanese Utility Model Application Publication No. 55-14224, the tip of the lead wire is formed into a cylindrical shape that is thinner and longer than the diameter of the fusible alloy, and the cylindrical part is connected to the fusible alloy. It is disclosed that a bulge part that is thicker and longer than the diameter of the fusible alloy is formed following the connection part. According to this temperature fuse, the intended purpose can be achieved, but the outer diameter of the fusible alloy needs to be larger than the outer diameter of the lead wire, which increases the amount of expensive fusible alloy used and increases the material cost. It is bulky, and it is difficult to align and fix the axes of lead wires with different outer diameters and the fusible alloy, resulting in high costs.

Therefore, this idea was proposed to solve the above problem.The opposing end surfaces of each lead wire are formed into a conical tapered surface, and this tapered surface is embedded in the end of the fusible alloy. It is characterized by:

Examples of this invention will be described below with reference to the drawings.

FIG. 2 shows a cross-sectional view of the first embodiment. In the figure, 11 and 12 are lead wires, the opposing end surfaces of which are formed into conical tapered surfaces 13 and 14, and the tapered surfaces 13 and 14 are connected to each other. , lead wire 1
A fusible alloy 15 having the same outer diameter as 1 and 12 is fixed with the tapered surfaces 13 and 14 embedded in the ends of the fusible alloy 15, and a flux 16 is adhered to the surface of the fusible alloy 15. It has been done. The fusible alloy 15 is inserted into an insulating cylinder 17 made of glass, ceramic, resin, etc., and a sealing resin 18 such as epoxy resin is inserted between the openings at both ends of the insulating cylinder 17 and the lead wires 11, 12. It is sealed by 19.

According to the above configuration, since the opposing end surfaces of each lead wire 11, 12 are formed into conical tapered surfaces 13, 14, when the lead wires 11, 12 and the fusible alloy 15 are fixed, the leads lines 11, 12
Even if the lead wires 11, 12 and the fusible alloy 15 have the same outer diameter, the tips of the tapered surfaces 13, 14 of the lead wires 11, 12 are used to projection weld the lead wires 11, 12 and the fusible alloy 15. and can be easily fixed without using low-temperature solder or the like. Further, as the fusible alloy 15, the lead wire 11,
Since a material having the same outer diameter as No. 12 can be used, the amount of expensive fusible alloy used can be reduced, and material costs can be reduced. Further, the fusible alloy 15 is connected to the lead wires 11 and 12.
When the outer diameter is the same as that of the outer diameter, the axes of the two can be easily and reliably aligned and fixed. In addition, since the tapered surfaces 13 and 14 of each lead wire 11 and 12 bite into the end surface of the fusible alloy 15, the adhesion between the lead wires 11 and 12 and the fusible alloy 15 is reliable and strong, and is not easily damaged by vibration or impact. The molten alloy 15 is the lead wire 11,
There is no chance of dropping out from 12. Furthermore, when the fusible alloy 15 melts due to an abnormal rise in ambient temperature, the tips of the lead wires 11 and 12
3 and 14, not only will the fusion area between the lead wires 11 and 12 and the melted fusible alloy 15 become large, but also the fusion between the two will become complicated, so that vibrations and shocks may cause damage. There is no possibility that the molten alloy will separate from the tips of the lead wires 11, 12 and cause problems.

FIG. 3 shows a sectional view of a second embodiment of the invention. In this embodiment, the lead wires 26 and 27 have enlarged portions 28 and 29 near their tips, and a tapered surface 3 at the tips.
0,31, the insulating cylinder 32 is fixed to the enlarged portions 28, 29, and the insulating cylinder 32 is filled with flux 33. This example uses lead wire 26.2.
7 is more complicated, but it has the advantage of being able to reduce the overall maximum outer diameter.

FIG. 4 shows a cross-sectional view of a third embodiment of the temperature fuse of the invention. In this example, lead wire 3
4 and 35 are bent in an L-shape, and tapered surfaces 36 and 37 are formed at the tips; a flux 38 is applied including the bent portions of the lead wires 36 and 37; It is characterized in that the surface thereof is covered with a sealing resin 39 such as epoxy resin. In this embodiment, since the flux 38 and the sealing resin 39 can be formed by dipping, there is an advantage that both material costs and processing costs can be reduced.

In each of the above embodiments, the fusible alloy 15 may be fixed to the lead wire through solder having a lower melting point than the fusible alloy 15. As shown in FIG. 1, lead wires 1,
When the opposing end surfaces of wires 2 and 2 are flat, if the fusible alloy 3 is fixed to the lead wires 1 and 2 via the low melting point solder as described above, the low melting point solder will melt before the fusible alloy 3 melts. This is impossible because the fusible alloy 3 would fall off from the lead wires 1 and 2, and therefore a fixing method such as welding would have to be used. However, with this idea, even if the low melting point solder melts, Since the protruding end surface of the lead wire can prevent the fusible alloy 15 from falling off, there is an advantage that there is a wider range of options for fixing the fusible alloy 15 and the lead wire.

As described above, this invention is based on a temperature fuse in which a fusible alloy is fixed between the opposing ends of a pair of lead wires, in which the opposing end surfaces of the lead wires are formed into conical tapered surfaces, and this tapered surface is made into a fusible alloy. Because it is embedded and fixed in the end of the alloy, the outer diameter of the fusible alloy can be made the same as the outer diameter of the lead wire, which not only reduces material costs, but also allows the lead wire and the fusible alloy to be connected to the axis. It can be easily, reliably and firmly fixed by aligning the hearts,
It is inexpensive, the fusible alloy does not separate from the lead wire due to vibration or impact, and it has the effect of providing a temperature fuse with high withstand voltage after operation.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional temperature fuse, and FIGS. 2 to 4 are sectional views of temperature fuses of different embodiments of this invention. 11, 12, 26, 27, 34, 35... Lead wire, 13, 14, 30, 31, 36, 37...
Tapered surface, 15... Fusible alloy, 16, 33, 3
8...Flux, 17, 32...Insulating cylinder, 1
8, 19, 39...Sealing resin.

Claims (1)

[Claims for Utility Model Registration] (1) In a temperature fuse formed by fixing a fusible alloy between opposing ends of a pair of lead wires, the opposing end surfaces of the lead wires are formed into conical tapered surfaces, and the tapered A temperature fuse characterized by having a face embedded in the end of a fusible alloy. (2) The temperature fuse according to claim 1, wherein the temperature fuse and the fusible alloy have substantially the same outer diameter.