JPH0462737A - Manufacture of temperature fuse - Google Patents

Abstract

PURPOSE:To improve yield by carrying out a process of heating a lead and a case between a process of inserting a soluble alloy with a lead welded into a case, and a process of applying a sealing resin on the opening end of the case. CONSTITUTION:A lead 2 held by a heating chuck 12 is heated by the chuck 12 to a temperature higher than the melting temperature of a soluble alloy 3, on both sides of the soluble alloys 3 held by a chuck 11, and then, each chuck 12 is brought close to one another, so as to press the front end of the lead 2 held by the chuck to both ends of the alloy 3, and to melt it thereby. After a flux is applied on the surface, the soluble alloy is inserted into a cylinder-shaped insulating case 4 held by a chuck 13, and is held by a chuck 14 in such a way that the alloy 3 is situated in the middle of the case 4. Warm air is blasted to these, which are heated to the temperature of 70-80 degrees, while the case 4 is sufficiently heated, and when a sealing resin 5 for which double-fluid epoxy resin is kneaded, is applied to its opening ends, it is ensured that the opening end is sealed, and when the resin 5 is hardened at a room temperature, a temperature fuse 1 is completed. The defective appearance or incomplete sealing can thus be prevented accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a temperature fuse that protects equipment by cutting off a circuit when overheated.

[Conventional technology]

As shown in FIG. 2, the temperature fuse 1 is of a fusible alloy type, in which a fusible alloy 3 is welded between two facing single-tooth wires 2, 2. This fusible alloy 3 is inserted into a cylindrical insulating case 4 made of ceramics or the like. Then, both open ends of the insulating case 4 are sealed with sealing resins δ and 5ζ made of epoxy resin, etc., so that only the wire wire 2°2 protrudes from the second sealing resin 5.5. The fusible alloy 3 is sealed inside. When the temperature fuse 1 having the structure shown in 2 is exposed to a high temperature higher than a set temperature, the fusible alloy 3 melts and the Riet wire 2.
By separating the two, it is possible to break the circuit.

A method of manufacturing the temperature fuse 1 will be explained with reference to FIG. First, as shown in FIG. 3A, the two grate wires 2.2 on both sides of the fusible alloy 3 are placed facing each other. Next, the wires 2.2 are brought close to each other while being heated, and their tips are pressed against the fusible alloy 3. Then, as shown in FIG. 2B, both ends of the fusible alloy 3 are melted and welded to the Riet wire 2.2. When the Riet wires 2, 2 are welded to the fusible alloy 3 as in step 2, the surface of the fusible alloy 3;
After applying this flux, insert it into the cylindrical insulating case 4 as shown in the same figure (c). Then, apply a sealing resin 5 made of epoxy resin or the like to both open ends of the second insulating case 4 and harden it; the temperature fuse 1 shown in FIG. 2 is now complete.

Then, apply the resin 5 as described above;
If the viscosity of the sealing resin 5 is too high, the wires 2 and the insulating case 4 may not be fully absorbed, as shown in Figure 4. . In addition, the viscosity of the sealing resin 5 made of epoxy resin changes over time and depending on temperature, etc., so even if it is manufactured in a somewhat controlled environment, it may change due to differences in temperature and humidity between summer and winter. There will be a difference in the finished state when it is cured.

Conventionally, after the sealing resin 5 is applied, it is heated to a temperature of about 80°C to 130°C, for example by blowing hot air.
A heating process was performed to reduce the viscosity of the sealing resin 5 and make it fit into the Riet wire 2 and the insulating case 4.

[Invention or problem to be solved]

In addition, as described above, when heating is performed after coating the sealing resin 5, this causes the bubbles inside the sealing resin 5 to expand. Then, when it hardens to a certain extent and the viscosity increases, the hole 5a near the surface will rupture due to expansion. : It becomes dull and the appearance of the product becomes defective. Particularly, when using this two-component heating type epoxy resin, air bubbles like the one shown in Fig. 2 are likely to be mixed in, and there will be many defects in appearance. Further, when the above-mentioned heating is continued once, the air inside the sealing resin 5 expands, and as shown in FIG. 6, the sealing resin 5 is pushed outward. For this reason, if the thickness of the sealing resin 5 becomes thin, there is a risk that a through hole 5b will be formed through the air bubbles, and in such a case, the product will be poorly sealed. For this reason, the above-mentioned conventional manufacturing method has had the problem of poor yield when manufacturing the temperature fuse 1.

[Means to solve the problem]

In order to solve the above problems, the present invention involves inserting a welded fusible alloy into the case, applying a sealing resin to the open end of the case, and hardening it. In the method for manufacturing a temperature fuse that seals the inside with It is characterized by a step of heating the Riet wire and the case.

[For production]

From this point on, the fusible alloy with the Riet wire welded to it is inserted into the case, the Riet wire and the case are heated, and then a sealing resin is applied to the open end of the second case. Then, the portion of the sealing resin that is in contact with the heated Riet wire and the case receives heat and reduces its viscosity. For this reason, the sealing resin has a high wettability to the glue wire and the case, and is well adapted to the sealing resin, so there is no need to heat the sealing resin after applying it as in the conventional case. Moreover, since the sealing resin is partially heated during application and is not heated after application, air bubbles mixed inside may expand and burst, or air inside the case may expand. There is no need to push out the second sealing resin to the outside.

〔Example〕

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

FIGS. 1(A) to 1(D) show one embodiment of the present invention, and are longitudinal cross-sectional views showing each step of a method for manufacturing a temperature fuse. Components having the same functions as the temperature fuses shown in FIGS. 2 and 3 to 6 are given the same numbers.

The method for manufacturing the temperature fuse of this embodiment is as shown in FIG.
On both sides of the fusible alloy 3 held in place, also a suitable length:
This is cut and held in a heating chuck 12° 12, and a tow wire 2, 2 is placed thereon. At the second time, the Riet wires 2, 2 are heated by the heating chuck 12.12 to a temperature higher than the melting temperature of the fusible alloy 3. Next, the heating chuck 12.1
Move 2 closer to each other; from here,
(Hold the tips of the wires 2 and 2 with the fusible alloy 3
Press it on both ends. Then, as shown in Figure (b); here, the pressed part of the fusible alloy 3 glue -) wires 2 and 2 melts, and the two welded It becomes.

As shown in Figure 2, the fusible alloy 3 is welded to the Riet wires 2, 2, 2 and 2 by applying flux to the surface of the fusible alloy 3. As shown, the chuck 13;
This is inserted into the cylindrical insulating case 4 in which it is held, and the chuck 14 is used to hold the fusible alloy 3 so that it is located at the center of the insulating case 4.

This insulating case 4 is made of ceramics or the like having insulating properties and heat resistance. In addition, when the fusible alloy 3 is welded in this way, or when the tow wires 2, 2 and the insulating case 4 are held, for example, by blowing hot air A onto them,
Heat to a temperature of about 70°C to 80°C. Fusible alloy 3
Usually has a melting point higher than 80°C, so there is a risk that the second Riet wire 2.2 and the insulating case 4 will melt due to heating.

As I said above, when the Riet wire 2.2 and the insulating case 4 are sufficiently heated, the same figure (d): As shown in this figure, both opening ends of the second insulating case J: This two liquid Apply a sealing resin δ prepared by kneading Epoquin resin. Then, the precision will decrease due to moderate heat (partial force in contact with the Riet wires 2, 2 and the insulating case J). For two, Kei 1
0 Resin 5: Well, since the wettability to these wires 2.2 and the insulating case 1 becomes high and they blend well, the open end can be reliably sealed as shown in the figure. Then, by hardening the second seal 5 at room temperature, the temperature fuse 1 shown in FIG. 2 is completed.

The problem with the manufacturing method of this embodiment explained above is that the resin 5 is only partially heated during coating, so the battery inside the sealing resin 5 may expand due to heating after coating, and the insulation case may be heated. This prevents the air inside 4 from expanding. Therefore, when the sealing resin 5 hardens, the air bubbles near the surface may burst and open, resulting in poor appearance of the product or the sealing resin 5.
is pushed by the air inside the insulating case 4, the wall thickness becomes thinner, a through hole opens, and there is no possibility of sealing failure.

The manufacturing method according to the above embodiment and the conventional manufacturing method: As a result of actually manufacturing the temperature fuse 1, it was found that the conventional method caused poor appearance of the product and i! While sealing defects occurred in about 0.5%, the method of this embodiment was able to reduce these defects to 0.2%.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the Riet wire and the case are heated before the sealing resin is applied, so that the sealing resin is well adapted to the wire and the case, and heating after application is prevented. Even if this is not done, the interior can be reliably sealed. Moreover, the sealing resin heats only the parts that come into contact with the wire and the case, so the air bubbles mixed inside may expand and burst, or the air inside the case may expand and cause the sealing resin to heat up. This eliminates the possibility of pushing out the through hole and opening the through hole.

Therefore, the method for manufacturing a temperature fuse of the present invention not only stably seals the inside of the case with the sealing resin, but also has the following effects: play.

[Brief explanation of drawings]

FIGS. 1(A) to 1(D) show one embodiment of the present invention, and are longitudinal cross-sectional views showing each step of a method for manufacturing a temperature fuse. FIG. 2 is a longitudinal sectional view showing the structure of the temperature fuse. 3 to 6 show conventional examples, and FIGS. 3(a) to 3(c) are vertical cross-sectional views showing each step of the method for manufacturing a temperature fuse, respectively, and FIG. 4 is a clever resin resin. Fig. 5 is a vertical cross-sectional view of the temperature fuse showing the state after application of the sealing resin; FIG. 2 is a partial vertical cross-sectional view of a thermal fuse that has failed in sealing due to an open through hole. 1...Temperature fuse, 2...Leet wire, 3...Fusible alloy, 4...Insulation case (case), 5...Kei J mouth fat. Patent applicant Kansai NEC Co., Ltd. Figure 4 Now M5

Claims (1)

[Claims] (1) A method for manufacturing a thermal fuse in which a fusible alloy welded to a lead wire is inserted into a case, and a sealing resin is applied to the open end of the case and cured to seal the inside. A process of heating the lead wire and the case is provided between the process of inserting the fusible alloy welded to the case into the case and the process of applying sealing resin to the front end of the case. Method of manufacturing fuses.