JP2002279878A - Thermal fuse and manufacturing method thereof - Google Patents

Abstract

(57) [Problem] To provide a thermal fuse in which heat transfer in a path from an electronic device to a low melting point fusible alloy is improved, and which has excellent quick disconnection property. SOLUTION: In the thermal fuse comprising a pair of flat terminals 11 and a low melting point fusible alloy 12 bridged between the distal ends of the pair of flat terminals 11, the pair of flat terminals 1 is provided.
1, at least one of the peripheral portions is configured to be equal to or not protrude from the central portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal fuse and a method for manufacturing the thermal fuse.

[0002]

In recent years, it has advanced the miniaturization of electronic devices,
For example, a battery pack for a mobile phone is conventionally 6 mm to 5 mm.
Although it is mm thick, a small and thin type battery pack having a thickness of 2.5 to 4 mm has been required. Since the heat capacity of such electronic devices is reduced due to their miniaturization,
There is a tendency for the rate of temperature rise during heat generation to increase.
Thus, fast-acting property of the thermal fuse used in these protection have been desired in the market.

A conventional thermal fuse is disclosed in Japanese Unexamined Patent Publication No. 2-2916.
No. 24 is known.

[0004] FIG. 5 (a) partially cutaway top view of a conventional temperature fuse, FIG. 5 (b) is a sectional view along line A-A in FIGS. 5 (a).

As shown in FIGS. 5A and 5B, a pair of flat terminals 1 are provided on the back surface of an insulating film 2, respectively.
Each tip portion is exposed from the back side to the front side of the insulating film 2. In addition, a low-melting-point fusible alloy 3 to which a flux is applied is connected between the exposed end portions of the pair of flat terminals 1. Further, the insulating film 4 for a cover is formed on the surface of the insulating film 2 so as to cover the low melting point fusible alloy 3.
Is arranged.

[0006] Figure 6 is a flat terminal 1 in FIG. 5 (a) B
FIG. 4 is a cross-sectional view taken along line B. As shown in FIG. 6, when the flat terminal 1 is observed in detail, protrusions 5 such as burrs are formed on the peripheral edge. When the flat terminal 1 is manufactured, a continuous long metal thin plate is used. This is inevitable in the process because the flat terminal 1 is manufactured by cutting into a piece.

FIG. 7A is a perspective view showing a state in which a conventional thermal fuse 6 is attached to an electronic device 7, and FIG. 7B is a sectional view taken along line AA of FIG. 7A.

As shown in FIG. 7 (b), the flat terminal 1 of the thermal fuse 6 is
There was a gap 8 between the electronic device 7 and the electronic device 7.

[0009]

However, in the above-mentioned conventional thermal fuse, as shown in FIGS. 7 (a) and 7 (b), the thermal fuse is electrically connected by the protrusion 5 on the peripheral edge of the flat terminal 1. when mounted to the device 7, since the gap 8 is formed between the flat terminal 1 and the electronic device 7, adhesion between the flat terminal 1 and the electronic device 7 of the thermal fuse is degraded, so that the electronic equipment abnormality In some cases, the heat generated at the time may be delayed from being transmitted to the thermal fuse, and may be delayed from being transmitted to the low melting point fusible alloy 3 of the thermal fuse. There was a problem of poor transmission.

[0010] The present invention is intended to solve the conventional problems described above, the heat transfer property is improved in the path from the electronic device to the low-melting fusible alloy, to provide a temperature fuse and a manufacturing method thereof immediate judgment is excellent The purpose is to.

[0011]

In order to achieve the above object, the present invention has the following arrangement.

[0012] The invention described in claim 1 of the present invention is, in particular,
At least one of the peripheral terminals of the pair of flat terminals is configured to be equal to or not protruded from the central portion compared to the central portion. According to this configuration, between the flat terminal of the thermal fuse and the electronic device. The effect of being able to improve the adhesion is obtained.

[0013] The invention described in claim 2 of the present invention is, in particular,
The flat terminal is provided with a rounded or inclined surface on the periphery.

[0014] The invention according to claim 3 of the present invention particularly provides
An insulating film is provided below the low-melting-point fusible alloy, and an insulating film for a cover that covers the upper part of the low-melting-point fusible alloy is fixed to this insulating film. This configuration prevents the deterioration of the low-melting-point fusible alloy. be able to. Also,
One or both of the insulating film and the cover insulating film have a longitudinal length of 7.5 mm or less, and a height from the lower surface of the insulating film to the upper surface of the cover insulating film of 1.5 mm or less. Therefore, an operational effect that the electronic device can be used for a small electronic device can be obtained.

[0015] The invention described in claim 4 of the present invention is, in particular,
Of the pair of flat plate terminals, which was equipped with a step of removing the burrs of at least one of the peripheral edge, according to this manufacturing method, it is possible to remove the burrs of the flat terminal, flat terminal and an electronic temperature fuse The effect of improving the adhesion to the device is obtained.

[0016] The invention described in claim 5 of the present invention, in particular,
The method includes a step of chamfering at least one peripheral edge of the pair of flat terminals. According to this manufacturing method, there is no projecting portion on the peripheral edge of the flat terminal. The effect of improving the adhesion to the device is obtained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thermal fuse according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a thermal fuse according to an embodiment of the present invention.

As shown in FIG. 1, a thermal fuse according to an embodiment of the present invention comprises a pair of flat terminals 11 and a low melting point fusible alloy 12 bridged between the tip portions of the pair of flat terminals 11. And a configuration in which at least one of the pair of flat terminals 11 (not shown in the drawing) is equal to or not protruded from the central portion.

Since the pair of flat terminals 11 are provided at both ends of the back surface of the insulating film 13 having two through holes, the flat terminals 11 are made of a highly conductive plate-like metal such as iron, copper, nickel, and the like. Its surface is plated with solder plating, tin plating, copper plating or the like. Further, the flat terminal 11 is configured such that the burrs on the peripheral edge are removed so that the peripheral edge does not protrude from the center. With this configuration,
When the flat terminal 11 of the thermal fuse is attached to the electronic device, the adhesion between the flat terminal 11 and the electronic device can be improved. Further, a bulging portion 11a is provided at one end of the flat terminal 11, and the bulging portion 1a is provided.
1 a is exposed from the back surface of the insulating film 13 to the upper surface through the through hole of the insulating film 13.

Since the plated flat terminal 11 is usually manufactured by cutting a continuous long metal thin plate into individual pieces, as described in the prior art, a protrusion such as a burr is formed on the peripheral edge. However, by removing the projections such as burrs or chamfering the peripheral edge, the peripheral edge is configured to be equal to or not protrude from the central portion. .

The low melting point fusible alloy 12 comprises an insulating film 13
And is bridged so as to be electrically connected between the tip portions of the pair of flat terminals 11, that is, between the bulging portions 11a, and is formed of two of tin, lead, bismuth, indium, cadmium and the like. are those composed of an alloy having the above metals. Note that a flux (not shown) is applied around the low melting point fusible alloy 12.

Here, the heat generated in the electronic equipment is conducted to the low melting point fusible alloy 12 through the flat plate terminal 11, and when the temperature of the low melting point fusible alloy 12 becomes higher than a certain level, the low melting point fusible alloy 12 Melts and breaks, and no current flows to the electronic device.

Accordingly, in one embodiment of the present invention, the burrs of the flat terminal 11 are removed as described above, and the burrs of the flat terminal 11 are removed because the peripheral portion does not protrude from the central portion. When the surface is attached to the electronic device,
Adhesion between the flat terminal 11 of the thermal fuse and the electronic device is good, thereby obtaining an effect of obtaining a thermal fuse with excellent quick disconnection.

[0025] On the upper surface of the insulating film 13, the cover insulating film 14 covering the upper side of the low-melting fusible alloy 12 is attached, This prevents such deterioration of the low-melting fusible alloy 12.

The insulating film 13 and the insulating film 14 for a cover are made of a thermoplastic resin such as polyethylene, polyethylene terephthalate and polyethylene naphthalate.

The insulating film 13 and the cover insulating film 14 have a longitudinal length L shown in FIG.
1 is not more than 7.5 mm, and a height L from the lower surface of the insulating film 13 to the upper surface of the insulating film 14 for a cover.
2 is 1.5 mm or less. This is, L1 is 7.5
If L2 is 1.5 mm or more and L2 is 1.5 mm or more, it becomes difficult to use it for small electronic devices, for example, small portable battery packs. The insulating film 13 and the cover insulating film 14 have a longitudinal length L1.
Are the same, but when the lengths are different, it is only necessary to set the longer length L1 to 7.5 mm or less.

[0028] Figure 2 is a manufacturing process diagram showing a manufacturing process of a thermal fuse in one embodiment of the present invention. Incidentally, FIG. 2 (a), (c), (d), (e), (f), (g) is a sectional view, FIG. 2 (b) is a perspective view.

First, as shown in FIG. 2A, a thin metal plate as a raw material of the flat terminal 11 is cut into a predetermined size.
At this time, burrs 16 are formed on the peripheral portion 15.

Next, as shown in FIG. 2 (b), crushing processing a sheet metal using a rolling roller 17. By this step, the burrs 16 are removed, and the flat terminal 11 whose peripheral portion 15 is equal to or not protruded from the central portion as shown in FIG. 2C is obtained.

Next, as shown in FIG. 2D, a bulging portion 11a is provided at the tip of the flat terminal 11. In this case, the flat terminal 11 has a surface on which the burrs are removed so that the peripheral portion 15 does not protrude from the central portion, is a surface opposite to the bulging portion 11a.

Next, as shown in FIG. 2E, a pair of swelling portions 11a are formed in the insulating film 13 having two through holes so that the bulging portions 11a are exposed from the back surface of the insulating film 13 to the upper surface through the through holes. The flat terminal 11 is set on the insulating film 13.

Next, as shown in FIG. 2 (f), the bulging part 1
A low melting point fusible alloy 12 is bridged between 1a, and a flux (not shown) is applied around the low melting point fusible alloy 12 of the bracket.

Next, FIG. 2 (g), the insulating film 1 cover so as to cover the upper side of the low-melting fusible alloy 12
4 is placed on the upper surface of the insulating film 13, and the periphery thereof is sealed using thermocompression bonding, ultrasonic welding, or the like.

The flat terminal 11 may be provided with a rounded or inclined surface by removing the burr 16 by chamfering the peripheral portion 15 by polishing or the like as shown in FIG. Things.

Further, one side of the flat terminal 11 which is not in contact with the electronic device or one of the two flat terminals 11 is not necessarily subjected to chamfering of the peripheral portion 15 or to a burr. They do not need to be removed.

A description will be given below of the results of comparison between the conventional thermal fuse and the thermal fuse according to one embodiment of the present invention in terms of quick disconnection.

As a sample, the same temperature fuse as that of the example was used except that ten thermal fuses according to one embodiment of the present invention were used as an example and a flat terminal that was not crushed was used as a comparative example. with 10 each.
In addition, a low melting point fusible alloy having a melting point of 95 ° C is used,
As shown in FIG. 4, each sample 18 was brought into close contact with the heat-generating component 19. At this time, in the example product, since the burr 16 does not exist on the flat terminal 11, the flat terminal 11 completely adheres to the heat generating component 19, but in the comparative example product, it does not completely adhere because of the burr existing in the flat terminal. .

The experimental method is as follows.
The temperature was set to 20 ° C., and the time from when the heat generating component 19 started generating heat to when the thermal fuse was blown was measured.

As a result, the product of the example was blown out in 12 to 15 seconds, whereas the product of the comparative example was blown out in 18 to 27 seconds. From these experimental results, it can be seen that a thermal fuse with excellent quick disconnection properties can be obtained by removing the burrs of the flat plate terminal as in the present invention.

[0041]

According to the present invention as described above, according to the present invention, a pair of flat plate terminals, since at least one of the peripheral portion than the central portion, configured so as not to protrude from the same or a central portion, the temperature fuse This makes it possible to improve the adhesiveness between the flat terminal and the electronic device, thereby providing an effect of obtaining a thermal fuse having an excellent quick disconnection property.

[Brief description of the drawings]

FIG. 1 is a sectional view of a thermal fuse according to an embodiment of the present invention.

FIGS. 2A to 2G are manufacturing process diagrams showing a manufacturing process of a thermal fuse.

FIG. 3 is a sectional view showing another example of the flat terminal.

FIG. 4 is a perspective view of a thermal fuse according to an embodiment of the present invention and a conventional thermal fuse adhered to a heat-generating component.

[5] (a) A-A line cross-sectional view of a partially cut away top view of a conventional thermal fuse (b) FIGS. 5 (a)

FIG. 6 is a sectional view taken along line BB of FIG.

7A is a perspective view showing a state in which the same temperature fuse is attached to a heat-generating component. FIG. 7B is a cross-sectional view taken along the line AA in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Flat terminal 12 Low melting point fusible alloy 13 Insulating film 14 Covering insulating film 15 Peripheral part 16 Burr

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masatoshi I ▲ zaki ▼ 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5G502 AA02 BA04 BC01 JJ01

Claims (5)

[Claims] 1. A thermal fuse comprising a pair of flat terminals and a low melting point fusible alloy bridged between the ends of the pair of flat terminals, wherein at least one of the pair of flat terminals has a peripheral edge. A thermal fuse whose part is equal to or does not protrude from the center compared to the center. 2. The thermal fuse according to claim 1, wherein a peripheral surface of the flat terminal is provided with a rounded or inclined surface. 3. An insulating film is provided below the low melting point fusible alloy, and a cover insulating film covering above the low melting point fusible alloy is fixed to the insulating film. 2. The thermal fuse according to claim 1, wherein one or both of the lengths in the longitudinal direction are 7.5 mm or less, and the height from the lower surface of the insulating film to the upper surface of the insulating film for a cover is 1.5 mm or less. . 4. A method of manufacturing a thermal fuse comprising a pair of flat terminals and a low melting point fusible alloy bridged between the tip portions of the pair of flat terminals, wherein at least one of the pair of flat terminals has a peripheral portion. A method for manufacturing a thermal fuse comprising a step of removing burrs. 5. A method for manufacturing a thermal fuse comprising a pair of flat terminals and a low-melting-point fusible alloy bridged between tips of the pair of flat terminals, wherein at least one of the pair of flat terminals has a peripheral portion. A method for manufacturing a thermal fuse, comprising a step of chamfering a surface.