JPS6245657B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD This invention relates to a method of manufacturing a thermal fuse.
More specifically, the present invention relates to an efficient manufacturing method of a non-resettable temperature fuse using a fusible alloy, which is used as an overtemperature rise prevention device for electrical equipment.

BACKGROUND ART Recent electrical equipment has come to have built-in temperature rise prevention devices from the viewpoint of safety. This temperature overrise prevention device includes a resetting type temperature switch using a bimetal and a non-resetting type temperature fuse using a thermosensitive pellet or fusible alloy made of an insulating chemical substance that melts at a specific temperature. be. Among the latter types of temperature fuses, those that use fusible alloys generally have a simpler structure and are cheaper than those that use temperature-sensitive pellets, and are often used in relatively inexpensive electrical equipment. .

FIG. 1 is a sectional view showing a typical conventional example of such a fusible alloy type temperature fuse. In the figure, numerals 1 and 2 are lead wires made of copper and having a circular cross section, the surfaces of which are soldered or otherwise plated, if necessary. Reference numeral 3 denotes a shaft-shaped fusible alloy made of two or more low melting point alloys such as Sn, Pb, In, Bi, and Cd, which is fixed by welding or the like between the ends of the lead wires 1 and 2. Reference numeral 4 denotes a flux for preventing oxidation and for removing an oxide film, which is coated on the surface of the fusible alloy 3 if necessary. Reference numeral 5 denotes a cylindrical insulating case made of ceramic, glass, heat-resistant resin, etc., into which the fusible alloy 3 is inserted. Numerals 6 and 7 are sealing resins made of epoxy resin or the like that close both open ends of the insulating case 5 and fix the lead wires 1 and 2 to the insulating case 5.

In the above configuration, if the ambient temperature rises too much,
Flux 4 first melts and flows onto the exposed surfaces of leads 1 and 2, removing the oxide film, and as the ambient temperature rises further, fusible alloy 3 melts. The molten fusible alloy flows onto the surfaces of the leads 1 and 2, aggregates due to the surface swelling force, and is separated into spheres 3a and 3b as shown in FIG. Therefore, the lead wires 1 and 2 become non-conductive, and the circuit is opened. When the ambient temperature decreases accordingly, the spheres 3a and 3b solidify while remaining fixed to the lead wires 1 and 2, so that the circuit remains open.

By the way, the above-mentioned temperature fuse has conventionally been manufactured by a method as shown in FIG. That is,
Cut a long solder-plated copper wire to an appropriate length,
Lead wires 1 and 2 are manufactured, and a fusible alloy 3 is manufactured by cutting a long fusible alloy wire into an appropriate length. Next, the fusible alloy 3 is fixed and integrated between the tips of the lead wires 1 and 2 by welding or the like to melt the alloy itself. Thereafter, flux 4 is applied to the surface of fusible alloy 3. Alternatively, flux 4 may be formed on the surface of the fusible alloy wire. This fusible alloy 3 is inserted into the insulating case 5,
Sealing resins 6 and 7 are applied to both open ends of the insulating case 5 to seal them.

However, according to the above manufacturing method, the lead wires 1 and 2 and the fusible alloy 3 are manufactured by being fixed together as a set, so this fixing work takes a considerable amount of time, and the processing cost is high despite the simple structure. The problem was that it was expensive.

DISCLOSURE OF THE INVENTION It is therefore a primary object of this invention to provide a less expensive method of manufacturing a fusible alloy type temperature fuse.

In summary, this invention involves manufacturing a bonded body in which a fusible alloy plate is integrally fixed between one end of a pair of lead plates, and cutting this bonded body to produce a bonded body in which a fusible alloy is fixed integrally between a pair of leads. The method is characterized in that it includes a step of manufacturing a strip-shaped combined body and encapsulating the fusible alloy portion in an insulating case.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows a process block diagram for explaining the manufacturing method according to the present invention, and FIGS.
The figure shows a plan view, a front view, and a partial sectional view of each stage. First, lead plates 100 and 110 are manufactured by cutting a solder-plated copper plate to an appropriate size, and a fusible alloy plate 120 with flux (not shown) coated on both sides is manufactured ( Figure 5). Next, the lead plates 100 and 110 are fixed to a pair of opposing sides of the fusible alloy plate 120 by welding or the like to produce the combined body 13 (FIG. 6). Next, the combined body 13 is pressed, and the lead plate 1 is
00, forming a cut 14 in a direction across the fusible alloy plate 120 and the lead plate 110, and connecting portions 15, 1 on the free end side of the lead plates 100, 110.
Holes 17 and 18 are bored at predetermined intervals in 6 (7th hole).
figure). When separated along the cut line 14, a large number of strips are formed in which the fusible alloy 12 is fixedly integrated between the pair of leads 10 and 11, and one end thereof forms a connecting portion 1.
Comb blade-shaped combined body 1 connected and integrated with 5 and 16
9,20 are obtained (Figure 8). This combination 1
9 and 20 are bent every other time up and down near the bases of the connecting portions 15 and 16 to form a stepped shape (FIG. 9). Then, the insulating case 21 is inserted into the free end of each strip-shaped combined body 19, 20 (FIG. 10). next,
Sealing resin 22, 2 is attached to both open ends of each insulating case 21.
3 and seal it (Fig. 11). After this,
By cutting and separating from the dot-dash line position 24 in FIG. 11, a temperature fuse as shown in FIG. 12 is obtained.

According to the above manufacturing method, the lead plate 100,1
10 and the fusible alloy plate 120 are fixed and cut to produce the strip-shaped combined bodies 19 and 20.
Compared to the conventional method in which a pair of lead wires 1, 2 and a shaft-shaped fusible alloy 3 are manufactured and then fixed one by one, the leads 10, 11 and the fusible alloy 12 can only be fixed at one time. No, lead 10,
11 and the fusible alloy 12 can be cut and separated at the same time, so processing costs can be significantly reduced. Further, by connecting and integrating one end of the strip-like combined bodies 19 and 20 with the connecting portions 15 and 16, the work of fitting and inserting the insulating case 21 into each of the strip-like combined bodies 19 and 20 can be automated. At this time, the connecting portion 15,
Through holes 17 and 18 bored in 16 serve as guides for positioning and intermittent feeding.

In the above embodiment, the case where the fusible alloy plate 120 is manufactured and fixed to the lead plates 100 and 110 has been described.
A molten alloy is poured into a mold in which lead plates 100 and 110 are arranged with a predetermined gap, and lead plates 100 and 11 are formed.
The fusible alloy plate 120 may be formed simultaneously with the fixation of the 0. Therefore, in FIG. 4, the fusible alloy plate 1
Only the blocks showing the 20 manufacturing steps are shown with broken lines.

Further, in the above embodiment, a case was described in which flux is applied to both sides of the fusible alloy plate 120 in advance, but the fusible alloy plate 120 may also contain flux, or may have a thin strip shape. Flux may be applied to the surface of the fusible alloy 12 after the combined bodies 19 and 20 are manufactured.

Further, by forming a film having poor wettability with the melted fusible alloy on the inner surface of the insulating case 21, there is an advantage that the melting of the fusible alloy 12 when it melts becomes more reliable. The coating can be formed of, for example, epoxy or polyurethane resin.

FIG. 13 shows a cross-sectional view of another construction of a fusible alloy type temperature fuse that can be made in accordance with the present invention.
This temperature fuse is connected to the insulating case 21 in FIG.
Instead of sealing with the sealing resins 22 and 23, the halved resin molded case 25 is sealed with adhesive or ultrasonic bonding.

BEST MODE FOR CARRYING OUT THE INVENTION The lead plates 100 and 110 are made of copper and solder plated on both sides, and the fusible alloy plate 120 is made of copper.
is coated with flux on both sides,
The solder plating layer allows the lead plates 100, 110 and the fusible alloy plate 120 to be easily and firmly bonded, and at the stage of manufacturing the strip-shaped joints 19, 20, flux is applied to each fusible alloy 12. is coated, and further a strip-like bonded body 19,
Reference numeral 20 denotes a structure that is integrally manufactured by connecting parts 15 and 16.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional fusible alloy type temperature fuse, Fig. 2 is a sectional view showing its state after operation, and Fig. 3 is a process block diagram for explaining the manufacturing method of the temperature fuse shown in Fig. 1. It is a diagram. Fig. 4 is a process block diagram for explaining the method of manufacturing a temperature fuse of the present invention, and Figs. 5 to 12 are plan views showing parts at each stage or partially in cross section according to the necessity of the temperature fuse, and a front view. It is a diagram. FIG. 13 is a cross-sectional view of another construction of a thermal fuse that can be made in accordance with the present invention. 100, 110... Lead plate, 120... Fusible alloy plate, 10, 11... Lead, 12... Fusible alloy, 13... Combined body, 14... Cut, 15, 16
... Connecting part, 17, 18 ... Through hole, 19, 20 ...
...Strip-shaped combined body, 21, 25...Insulating case,
22, 23...Sealing resin.

Claims (1)

[Claims] 1. A step of manufacturing a combined body in which a fusible alloy plate is integrally fixed between one end of a pair of lead plates, and a process of cutting the combined body and fixing the fusible alloy integrally between the pair of leads. 1. A method for manufacturing a temperature fuse, comprising the steps of: manufacturing a strip-shaped composite body fixed to a material; and enclosing a fusible alloy of the strip-shaped composite body in an insulating case. 2. The strip-shaped combined body is a comb blade-shaped body in which a plurality of strip-shaped combined bodies are connected at a predetermined interval and at one end, and is cut and separated after being sealed in an insulating case. How to make fuses. 3. The method of manufacturing a temperature fuse according to claim 1, wherein the fusible alloy plate is manufactured by casting between a pair of lead plates.