JPS59151724A - Method of producing 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 [Technical Field of the Invention] The present invention relates to a method for manufacturing a high-temperature fuse (150° C. or higher) in which fusible pellets are housed in a cylindrical conductive case.

[Technical background of the invention and its problems] In general, a fusible pellet type temperature fuse, as shown in FIG. A movable conductive plate 4 is disposed via a hold spring 5, and a ceramic insulator 8 supporting an input lead wire 7 via a bushing spring 6 is disposed on the side surface of the movable conductive plate 4. A sealing layer 9 made of thermosetting resin such as epoxy resin is provided on the outer edge of 8.

In the temperature fuse configured in this way, since the soluble pellet 3 is solid at room temperature, the soluble pellet 3 and the movable conductive plate 4 are maintained at a constant distance, and the conductive case 2
A conductive path is formed between the output lead wire 1 and the input lead wire 7 via, etc., but when the temperature rises abnormally, the soluble pellet 3 melts and the hold spring 5 changes from a compressed state to an expanded state. Due to the elastic force of the bushing spring 6, the movable conductive plate 4 moves to the left in the figure and is separated from the tip of the input lead wire 7, thereby interrupting the conductive path.

By the way, conventionally, in order to manufacture such a temperature fuse, each component is assembled in the conductive case 2, a sealing layer 9 of thermosetting resin is provided on the outer edge of the insulator 8, and then the thermosetting resin is placed in a thermostatic oven and heated to high temperature. (100-150℃) for a long time (1-2 hours)
A method is used in which the resin is cured by heating, but in this method, the moisture inside the conductive case 2 escapes outward along the inner and outer peripheral surfaces of the insulator 8 during heating, so that air bubbles are formed in the sealing layer 9. etc., resulting in a decrease in withstand voltage characteristics and poor appearance. Additionally, it takes a long time to completely cure the thermosetting resin, resulting in low productivity.

Roughly speaking, each part assembled into the conductive case 2 is placed in a constant temperature oven and heated at a temperature of 80 to 100°C for about 5 hours to dry the inside of the conductive case 2, and then immediately the outer edge of the insulator 8 is heated. A method has also been developed in which a sealing layer 9 made of a photocurable resin composition is provided thereon and the photocurable resin composition is cured by irradiating it with ultraviolet rays for 15 to 20 minutes.

However, in the temperature fuse obtained by this method, the adhesive strength of the sealing layer 9 is low, especially at high temperatures, and the sealing performance is incomplete, so that the melted soluble pellets 3 bond between the sealing layer 9 and the insulator 8. The problem was that water leaked through the gaps between the pipes.

In addition, at high temperatures, the internal pressure of the conductive case 2 is 0.2 to 0,
3 kg/'c! As a result, the molten soluble pellet 3 moves against the elastic force of the hold spring 5 and moves onto the movable conductive plate 4.
Since the movable conductive plate 4 and the input lead wire 7 are pressed in the right direction, it is difficult to completely separate the movable conductive plate 4 and the input lead wire 7, and there is a drawback that fusing failure is likely to occur.

[Object of the Invention] The present invention has been made in order to eliminate such conventional drawbacks, and it is an object of the present invention to provide a method for efficiently manufacturing a temperature fuse that is completely sealed by a sealing layer and has good appearance and characteristics. With the goal.

``Summary of the Invention'' That is, the method for manufacturing a temperature fuse of the present invention consists of a cylindrical conductive case with an output lead connected to one end, a fusible pellet (~, a hold spring, a movable conductive plate, a bushing spring, and an input After sequentially storing the insulators supporting the lead wires and bringing the opening periphery of the conductive case into close contact with the outer edge of the insulator, heating is performed to dry the inside of the conductive case,
In this state, a metal ion-curable acrylic resin composition is applied to each contact portion between the outer edge of the insulator, the periphery of the opening of the conductive case, and the input lead wire, and cured. The present invention is characterized in that a thermosetting epoxy resin composition is roughly applied onto the periphery of the opening of the conductive case and cured.

In the present invention, there are various methods for heating the inside of the conductive case for dehydration and drying. It is preferable to insert it into a holder, and it is appropriate to hold it at a temperature of 70 to 80° C. for 3 to 5 minutes in this state.

The metal ion-curable acrylic resin used for the primary seal of the present invention includes, for example, #1360 manufactured by ThreeBond. The thermosetting 1-boxy resin used for the secondary seal is a high-temperature epoxy resin that is cured with an acid anhydride, such as ThreeBond Inc. #2062.

The reason why a metal ion-curable acrylic resin is used for the primary seal and a thermosetting epoxy resin is used for the secondary seal in the present invention is that such a structure improves adhesion and heat resistance in particular.

“Embodiments of the invention” Next, examples of the present invention will be described.

Embodiment As shown in FIG. 2, a fusible pellet 1 is placed in a cylindrical metal conductive case 11 with an output lead wire 10 connected to one end.
2. Hold spring 13, movable conductive plate 14, bushing spring 15, and ceramic insulator 17 that supported input lead wire 16 are sequentially housed in conductive case 11.
After bringing the periphery of the opening into close contact with the outer edge of the insulator 17, the whole is inserted into a heating holder (not shown) maintained at a temperature of 70 to 80°C, and heated for 3 to 5 minutes to form a conductive case. Dry the inside of the insulator 11, and in this state, apply #1360 (manufactured by Three Bond, anaerobic metal ion hardening type) on each contact area between the outer edge of the insulator 17, the opening periphery of the conductive case 11, and the input lead wire 16. After the first sealing layer 18 was provided by depositing an acrylic resin composition (trade name), the first sealing layer 18 was cured by ultraviolet irradiation.

Next, #2 is further placed on the outer edge of the insulator 17 and on the front junction.
062 (trade name of a high-temperature thermosetting epoxy resin composition manufactured by ThreeBond) to form the second sealing layer 19, the second sealing layer 19 is completely heated by heating in a thermostatic oven. hardened to.

The temperature fuse obtained in this way has no air bubbles or minute holes in the primary and secondary sealing layers 18.19, has a good appearance, and has been tested in the prescribed withstand voltage test (immediately after the pellet fusing test). It completely passed the test of withstanding a voltage of 1.5 kV for 1 minute.

In addition, the soluble pellets 12 melted even in a high temperature atmosphere.
There was no leakage to the outside, and no fusing defects occurred.

[Effects of the Invention] As is clear from the above examples, according to the present invention, a temperature fuse with good appearance and characteristics can be manufactured with good productivity without leakage of the melt of the soluble pellets during fusing. .

[Brief explanation of drawings]

FIG. 1 is a sectional view for explaining a conventional method of manufacturing a temperature fuse, and FIG. 2 is a sectional view for explaining an embodiment of the present invention. 1.10... Output lead wire 2.11... Conductive case 3.12... Fusible pellet 4.14... Movable conductive plate 5.13... Hold spring 6.15... Item Spring 7.16 Input lead wire 8.17 Insulator 9 Seal layer

Claims (1)

[Claims] (1) In a cylindrical conductive case with an output lead wire connected to one end, a fusible pellet, a hold spring, a movable floor plate, a push spring lug, and an insulator supporting an input lead wire are sequentially stored, and After bringing the opening edge of the conductive coupe into close contact with the outer edge of the insulator, the inside of the conductive case is dried by heating, and in this state, the outer edge of the insulator, the opening edge of the conductive case, and the input lead wire are connected to each other. A metal ion-curable acrylic resin composition is applied to the contact portion and cured, and then a thermosetting epoxy resin composition is further applied and cured to the outer edge of the insulator and the periphery of the opening of the conductive case. A method for manufacturing a temperature fuse, characterized by: