JPS58192236A - 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 In addition to the miniaturization and higher density of electronic equipment, there is an increasing demand for equipment safety. SUMMARY OF THE INVENTION An object of the present invention is to provide a small fuse suitable for being attached to a circuit board or the like to protect circuits in blocks.

Conventional fuses are generally made by enclosing a fusible metal thin wire in a glass tube, connecting metal caps to both ends, or having leads 1fiAf drawn out from both ends. But the former? In addition, all types are limited to axial types with terminals pulled out from both ends of the glass tube, and they have a large space inside the glass tube and are thick in shape so that they can be incorporated into circuit boards, etc. It is difficult to make it into a small chip shape.The present invention connects metal terminals f to both ends of a thin plate or thin wire of a fusible metal such as Pb-Sn alloy, copper, Pb, Sn, etc. that can be used as a fuse. Fusible metal plate or metal #i
The exterior is formed by molding with resin such as epoxy resin in close contact with lK.

As mentioned above, when the resin is tightly molded and a current exceeding a certain limit is passed through the fusible metal, the temperature of the fusible metal rises and expands, and at the same time the resin surrounding it expands. softens and expands due to Joule heat. As a result, the softened resin expands outward due to internal pressure, creating a space at the interface with the fusible metal, causing the soft resin inside to move and melting the fusible metal. This is based on the principle that f8 is cut off by movement.

Therefore, when melting occurs, it does not occur instantly and explosively;
A fuse that is extremely safe because it takes only a few seconds to cause molten metal to explode and scatter. Obtainable. Additionally, since this fuse has no space between the fusible metal and the exterior, and is entirely solid, it can be made smaller than conventional fuses, and there is no risk of damage due to vibration or impact. In addition, it has the feature that it is possible to freely create various shapes of blades, such as axial type where the terminal is pulled out from both ends of the terminal tube exterior, radial type where the terminal is pulled out in the same direction, square shape, cylindrical shape, etc. It is.

Next, the present invention will be described in detail with reference to the drawings.

Figure 1 shows the internal structure of the rectangular chip-shaped fuse according to the present invention. Figure 2 is a side sectional view (a) and a bottom view (
b). (1) is Pb-8n alloy or Pb, S,
A thin plate or thin string of fusible metal that spans a fuse such as 0.1 mm on both ends. A pair of terminals (2+, (3)) soldered on a steel plate with a thickness of A sheath (4) is molded to form a sheath (4) in close contact with the fusible metal, and then the metal terminal (2+, (3)) pulled out from the end face of the sheath is bent downward at an almost right angle along the end face of the sheath. Furthermore, it is constructed by bending the bottom part inward at almost a right angle.In factory production, a pair of terminals f21. A so-called comb terminal is made by punching it into a comb shape, and a fusible metal is welded between a pair of facing terminals of the comb terminal to continuously make the comb terminal. Terminal (z+, (3) Ice, Figure 2 (a) K
As shown, if you pull it out above the center in the height direction M It is very difficult to solder as it is close to the
[This is convenient because good products are made.

I[! Figure 3 shows the next state when a large current is passed through the above-mentioned fuse, and the fusible metal (11) is fused. At the fused part (5), the resin becomes soft due to Joule heat, the metal melts, and its surface tension increases. Thick parts are formed on both sides of the fusing part by being pulled on both sides.

The exterior resin is preferably a heat-resistant thermosetting resin such as an epoxy resin or a silicone resin, and a heat-resistant thermoplastic resin such as PP5 (polyphenylene sulfide) resin is also preferable. Also, if you use transparent epoxy resin,
This is convenient because it allows you to visually check the melting state of the fusible metal inside. Furthermore, the resin is preferably flame retardant or nonflammable. In addition, K that melts in a short time is
In order to prevent the rapid heat generated by Joule heat from escaping to the outside, it is best to use a material with poor thermal conductivity, and use one whose exterior resin has a thermal conductivity of 20 x 1 "6" cab, sec-cm or less. When doing so, it is possible to obtain a material with very good characteristics that can be fused and cut without increasing the surface temperature tL1r of the outer casing.

FIG. 4 shows another embodiment of the present invention having the same shape as a general discrete component; (a) is a perspective view showing the internal structure; (a) is a perspective view showing the internal structure;
b) is a side sectional view, and (e) is a bottom view. In this example, two parallel metal lead wires (ell, (7
) of Seki KEJ fusible metals (1)? The embodiment shown in Fig. 1 is described and connected in the same manner as shown below.
1. (7)! A radial type resin molded fuse is formed by molding the exterior (41Yr) so that it can be pulled out in the same direction. Figure 5 shows the fuse in Figure 4 in a blown state.

Fig. 6 shows the present invention in which the ends of the lead wires +6) and (7) of the radial resin molded fuse shown in Fig. 4 are processed to form external terminals (8) and 79) f to form a chip-shaped fuse. Other examples? (a) is a perspective view showing its internal structure, (c) is a side sectional view, and (c) is a bottom view.

As described above, according to the present invention, it is possible to freely create a fuse that is small, safe, suitable for mounting on a circuit board, strong against imaging and external impact, and has an arbitrary shape.

[Brief explanation of drawings]

FIG. 1 is an fA view showing the internal structure of an embodiment of a fuse according to the present invention, and FIG. 2 is a side sectional view (a) and a bottom view (
Figures b) and 4) are IP4 perspective views showing nine-shaped fuses in Figure 1 that are blown, and Figure 4 is a perspective view (a) and a side sectional view (b) showing the internal structure of another embodiment of the present invention. ) and bottom view (c)
, FIG. 5 is a perspective view showing a state in which the fuse shown in FIG. 4 is blown, and FIG. 6 is a perspective view (a) and a side sectional view (b) showing the internal structure of still another embodiment of the present invention. And bottom view (c) 〇 (1) -- Fusible metal, (21, (3), (1N,
f9j・-・Terminal, (4)...Resin exterior, (5)・
-・Fusion part, +61. (7)...Lead wire. Name of agent Patent attorney Etsuji Yoshizaki Saba 1 Figure 7'1'', ----Figure a 4 Figure (b) 5 Figure 6 (G) 7, ゛・~ Figure 146 (C)

Claims (1)

[Claims] 1. Both ends of a thin plate-like or thin wire-like fusible metal [a pair of metal terminals are connected, and this is molded in a resin mold in close contact with the fusible metal so that the pair of metal terminals is pulled out to the outside. And the resin exterior? In formation, f should be less than 5ec-σ
A fuse according to claim 1, characterized in that: