JPS6118595Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a fusible alloy type temperature fuse.

Electrical equipment has come to have built-in temperature rise prevention devices for safety reasons. This type of overheat prevention device includes resetting types such as bimetallic switches and non-resetting types such as temperature fuses using temperature-sensitive pellets made of fusible alloys or insulating organic chemicals. There is. The former type, which can be reset, is convenient when controlling the temperature below a certain value because even if it is activated once the ambient temperature rises abnormally, it will return to its original state when the ambient temperature drops. However, when viewed as a final safety device, even if it activates and opens the circuit when the ambient temperature rises abnormally, the circuit will close again when the ambient temperature drops, so the cause of the abnormal temperature rise will not be removed. As a result of repeated opening and closing operations, the contacts will eventually weld and the circuit will remain closed, which is dangerous. On the other hand, the latter non-reset type has the advantage of being safe because it does not return to its original state once it is activated, but it is safe because it does not return to its original state once it is activated. If it seems to work, there is the inconvenience of having to replace it with a new one. Therefore, a double safety mechanism is generally adopted in which temperature control is performed by a resettable bimetal switch, and ultimate safety is ensured by a non-resettable temperature fuse.

Among the above-mentioned temperature fuses, those using temperature-sensitive pellets made of insulating organic chemical substances generally have complicated structures including springs, movable contacts, etc., and are expensive. On the other hand, those using fusible alloys generally have a simple structure and are inexpensive. An example of the latter fusible alloy type temperature fuse has the structure shown in FIG. In the figure, numerals 1 and 2 are lead wires, and a fusible alloy 3 is fixed between their opposing ends. This fusible alloy 3 has a cylindrical shape, and a cavity 4 inside thereof is filled with flux 5. The tips of the lead wires 1 and 2 and the fusible alloy 3 are housed in an insulating cylinder 6 made of glass, porcelain, heat-resistant shaft fat, etc. , 2 is a sealing resin 7, 8 such as epoxy resin.
It is sealed by.

In the above configuration, when the ambient temperature rises excessively, first the flux 5 melts, and then the fusible alloy 3 melts, so that the melted fusible alloy aggregates at the tip of each lead wire 1, 2. , lead wire 1,
However, in the conventional fusible alloy 3, as is clear from FIG.
Since the fusible alloy 3 has a sealed structure that is completely isolated from the outside of the fusible alloy 3, it will not flow out unless the fusible alloy 3 is melted, as described above. Therefore, if an oxide film were to be formed on the surface of the fusible alloy 3, there was a problem that the melting point of the fusible alloy 3 would become high.

This invention was proposed to solve the above problems, and examples thereof will be described below with reference to the drawings.

Figure 3 shows the first fusible alloy, which is the main part of this invention.
FIG. 3A is a side view, and FIG. 3B is a side view.
is a sectional view. In the figure, reference numeral 10 denotes a fusible alloy, which has a cylindrical shape and has a cavity 11 inside. It communicates with the outside of the molten alloy 10. The cavity 11 is filled with flux 13. Other structures are the same as, for example, in FIG. 1, so illustrations are omitted.

In the above configuration, if the ambient temperature rises too much,
First, the flux 13 melts and flows out through the slits 12 to the surface of the fusible alloy 10. Therefore, even if an oxide film is formed on the surface of the fusible alloy 10, the oxide film is removed by the flux 13 and the fresh surface of the fusible alloy 10 is exposed.
Since the melting point of the fusible alloy 10 does not rise due to the presence of the oxide film, and the fusible alloy 10 reliably melts at a predetermined operating temperature, a highly reliable temperature fuse is obtained.

FIG. 4 shows another embodiment of the fusible alloy which is the essential part of the temperature fuse of this invention, with FIG. 4A being a side view and FIG. 4B being a sectional view. In the figure, 20
is a fusible alloy, and has a cavity 21 with a V-shaped cross section cut out at a predetermined angle along its longitudinal direction, and this cavity 21 is filled with flux 22. A temperature fuse using such a fusible alloy also exhibits the same effects as those of the above embodiment.

FIG. 5 shows the fusible alloy which is the main part of the temperature fuse of the third embodiment of this invention, FIG. 5A is a side view, and FIG. 5B is a sectional view. In the figure, 3
0 is a fusible alloy, which has a plurality of cavities 31 with semicircular cross sections along its longitudinal direction, and each cavity 31
is filled with flux 32. Even in a temperature fuse including such a fusible alloy, the same effects as in the above embodiment can be obtained. In addition, since the flux 32 is arranged at multiple locations along the circumferential direction of the fusible alloy 30, there is an advantage that the oxide film removal effect by the flux 32 can be reliably obtained regardless of the mounting direction of the temperature fuse. be.

FIG. 6 shows the fusible alloy which is the main part of the temperature fuse of the fourth embodiment of this invention, FIG. 6A is a side view, and FIG. 6B is a sectional view. The feature of this embodiment is that a cavity 41 is provided in the middle of the fusible alloy 40 in the longitudinal direction and penetrates to the opposite side, and this cavity 41 is filled with flux 42. In a temperature fuse including such a fusible alloy, not only can the same effects as in the above embodiment be obtained, but also there is only one cavity 41, which has the advantage that filling the flux 42 is easy.

Note that although the above embodiments have been described with reference to specific structural examples, those skilled in the art will easily understand that various structures can be devised without departing from the spirit of the present invention.

As described above, this invention provides a temperature fuse using a fusible alloy having flux, in which the fusible alloy has a cavity at least partially communicating with the outside, and this cavity is filled with flux. Since the flux flows to the surface of the fusible alloy before it melts and removes the oxide film on the surface of the fusible alloy, a reliable temperature fuse with the correct operating temperature is obtained. It has the effect of being covered.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional fusible alloy type temperature fuse, Fig. 2 is an enlarged sectional view taken along the - line in Fig. 1, and Figs. 3 to 6 are the first to fourth implementations of this invention. Showing the temperature fuse, which is the main part of the example,
3A to 6A are side views, and FIGS. 3B to 6B are sectional views. 10, 20, 30, 40...fusible alloy, 11,
21, 31, 41...Cavity, 12...Slit, 1
3, 22, 32, 42...Flux.

Claims (1)

[Scope of utility model registration request] 1. A temperature fuse using a fusible alloy having flux, wherein the fusible alloy has a cavity at least partially communicating with the outside, and the cavity is filled with flux.