JPH0646536B2 - Fuse, low melting point chip for fuse, and manufacturing method thereof - Google Patents

Description

The present invention relates to a fuse, a low melting point chip for a fuse, and a method for manufacturing the same, and more particularly, to prevent the flux disposed inside from being exposed to the outside. The present invention relates to a product that is sealed with a low melting point metal to prevent flux from leaking or coming into contact with the outside air.

(Prior Art) As a block type fuse, for example, as shown in FIG. 5, a fusible body portion 100 made of copper or a copper alloy, and tin, a tin alloy, etc. attached to a fusing portion 110 provided in the fusible body portion 100 are used. Low melting point chip 200 and terminal portions 300 arranged vertically at both ends in the longitudinal direction of the fusible body portion 100,
It is known that it is composed of 300 and 300 (Japanese Patent Laid-Open Publication No. 61-61
-66329 gazette).

When an abnormal current flows in the circuit, the fusing part 1 of the fusible part 100
Although 10 melts and cuts off the circuit, in order to lower the melting temperature at the time of this melting to reduce the thermal influence on peripheral equipment, the heat generated by the abnormal current has a lower melting point than the fusible body 100. The melting point chip 200 is melted, and an intermetallic compound is formed between the melting point chip 200 and the low melting point chip 200. When the intermetallic compound is formed in this way, the melting temperature of the fusing part 110 can be made lower than the red heat temperature of the fusible part 100. For example, when the fusing part 110 is formed of copper, the melting temperature can be lowered from 1080 ° C. to about 600 ° C. by forming an intermetallic compound.

During the formation of the intermetallic compound, the fusible portion 100 (fusing portion 110) and the oxide film on the surface of the low melting point chip 200 are removed to activate the boundary surface between the fusing portion 110 and the low melting point chip 200, and the intermetallic compound is formed. The flux 400 is disposed inside the low melting point chip 200 in order to promote the formation of the flux.

(Problems to be Solved by the Invention) In the low melting point chip 200, for example, as shown in FIG. 6 and FIG.
00 is inserted into a hole 610 of a cutting machine 600 such as a shear until it abuts a stopper 620, and a cutting blade 63
However, since the flux 400 is exposed at both axial end surfaces (cut surfaces) of the low melting point chip 200 as shown in FIG. 6, the following problems occur. there were.

That is, when the powder 400 is used as the flux 400 in a compacted state, the low melting point chip 200 is attached to the fusible body 100, the fusible body 100 is assembled to other parts, or the like. And flux 4
There was a problem that 00 collapsed outside.

In addition, when a rosin-based flux is used as the flux 400, it easily absorbs moisture, so that when it comes into contact with the outside air, it absorbs moisture and becomes a liquid, and flows out, or the oxide film removal action deteriorates and the intermetallic The formation of the compound does not proceed well, and the effect of the low melting point chip 200 (the effect of lowering the melting temperature)
However, there is a problem in that the low melting point chip 200 is not utilized, and tin or the like that constitutes the low melting point chip 200 is scattered to the peripheral portion due to the moisture in the flux 400 when the low melting point chip 200 is melted.

In other words, since the flux 400 is exposed on the cut surface of the low-melting point chip 200, the effect of the low-melting point chip 200 is reduced, and there is a problem that melting at a low temperature becomes impossible.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object thereof is to provide a fuse having an effect such that the effect of a low melting point chip does not decrease and the fuse can be blown at a low temperature. Another object of the present invention is to provide a low melting point chip for a fuse and a manufacturing method thereof.

[Structure of Invention]

(Means for Solving the Problems) In order to achieve the above object, in the fuse of the present invention, in the fuse in which the low melting point chip is attached to the fusing part provided in the fusible body part, the low melting point chip is made of a low melting point metal. It is characterized in that a flux is arranged inside the chip, and the entire surface of the flux is covered with a low melting point metal so as to prevent the flux from being exposed to the outside, and the chip is sealed.

Further, in the low melting point chip for a fuse of the present invention, in the low melting point chip arranged in the fusing part provided in the fuse melting body part, the flux is arranged inside the chip made of the low melting point metal, and the flux is discharged to the outside. It is characterized in that the entire surface of the flux is covered with a low melting point metal so as not to be exposed and sealed.

Further, in the method for manufacturing a low melting point chip for a fuse of the present invention, a wire made of a low melting point metal having a flux disposed therein is squeezed to a predetermined length by a pair of cutting blades facing each other with the wire sandwiched therebetween. It is characterized in that the cut surface is closed with the low melting point metal so that the internal flux is not exposed to the outside.

In the fuse and the low melting point chip for a fuse of the present invention, "closing both ends of the chip" means narrowing by closing both ends of the chip made of a flexible low melting point metal such as tin or solder by drawing. Say that. In addition to this, for example, heat may be applied to both end portions to melt and close a part of the chip itself, or both end portions may be closed by melting a melt of the same low melting point metal.

The "fusible body portion" is formed of, for example, copper, copper alloy, tin-plated copper, aluminum or the like.

Further, as the "flux", a rosin-based flux, which is less corrosive to the terminal metal, has no toxicity and is safe, is used.

Further, in the method for manufacturing a low melting point chip for a fuse of the present invention, "to apply a squeeze to a cutting portion with a cutting blade to cut it to a predetermined length" has, for example, a predetermined tip angle and a sharp tip. The wire rod is sandwiched between a pair of cutting blades formed on the wire, and the wire rod is squeezed by the inclined side surface on the tip side of the cutting blade to close the hole inside the wire rod where the flux is placed, or the tip is almost flat. A wire rod is sandwiched between a pair of cutting blades formed in a shape, the wire rod is squeezed by crushing the wire rod at the flat part at the tip of the cutting blade, and the wire rod is cut by closing the hole inside the wire rod where the flux is arranged. Say.

(Function) Since the periphery of the low melting point chip is closed and the flux placed inside is not exposed to the outside, the flux does not fall outside during assembly. Even if a rosin-based flux is used, there is no risk of absorbing moisture, the flux does not flow out in a liquid state, and the oxide film removing action does not deteriorate.

Therefore, when the low melting point chip is melted by the heat generated by the abnormal current and an intermetallic compound is formed between the low melting point chip and the low melting point chip, the flux is melted into the fusible part (fusing part) or the low melting point chip. It is possible to accelerate the formation of the intermetallic compound by removing the oxide film on the surface of the element and activating the boundary surface between the fusing part and the low melting point chip. That is, the effect of the low melting point chip can be fully utilized.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a low melting point chip for a fuse of the present invention, and FIGS. 2 (a) and 2 (b) are perspective views showing the appearance. In the figure, reference numeral 20 is a low melting point chip, and a rosin-based flux 4 is provided in a hole 22 inside a chip 21 having a circular or rectangular cross section made of a low melting point metal such as tin or solder.
It is configured by filling with 0. Both ends 21a of the tip 21 in the axial direction are tapered and closed by, for example, drawing so that the internal flux 40 is not exposed to the outside.

As means for closing the axial end portions 21a, in addition to tapering by closing by drawing, for example, heat is applied to the axial end portions 21a to melt and close a part of the chip 21 itself, or the axial direction end portions 21a are closed. There is a method in which a low melting point metal melt is fused and closed at both ends 21a.

FIG. 3 (a) is an explanatory sectional view showing an embodiment of a method of manufacturing a low melting point chip for a fuse according to the present invention.

In this embodiment, the tip is sharply formed and the tip angle is 3
A cutting machine equipped with a pair of cutting blades 60, 60 set at 0 ° to 70 ° is used. In addition, the low melting point chip 20
The wire 50 for manufacturing is made of a low melting point metal such as tin or solder having the flux 40 filled therein, and has a circular cross section.

When manufacturing the low melting point chip 20, first, the wire 50 is fed into a cutting machine of a predetermined length (about several mm), and then the cutting blade 6
The wire rod 50 is sandwiched between 0 and 60 and cut. In the process of this cutting, the wire rod 50 is moved by the side surface 61 on the tip side of the cutting blade 60.
A squeezing point is applied to the cutting point of (1) to close the hole 22 filled with the flux 40 inside the wire rod 50. The cutting of the wire rod 50 is performed almost at the same time when the hole 22 is closed in this way. As a result, as shown in FIGS. 1 and 2A, a low melting point chip 20 having a circular cross-section and having both axial ends 21a tapered and closed is manufactured.

FIG. 3 (b) is an explanatory sectional view showing another example of the method of manufacturing the low melting point chip for fuses of the present invention. In this embodiment, the tip angle is set to 30 ° to 70 °, but the pair of cutting blades 6 whose tips are not sharp and are formed in a substantially trapezoidal shape.
I am using 2, 62. Further, the wire rod 50 for manufacturing the low melting point chip 20 is formed in a rectangular cross section, not a circular cross section.

When manufacturing the low melting point chip 20, first, the wire 50 is fed into a cutting machine of a predetermined length (about several mm), and then the cutting blade 6
The wire rod 50 is sandwiched and cut by 2, 62. In the course of this cutting, the tip flat portion 63 of the cutting blade 62 squeezes the cutting portion of the wire rod 50 so that the hole 22 filled with the flux 40 inside the wire rod 50 is closed. The cutting of the wire 50 is performed by the blade portion 64 at the center position of the flat tip portion 63 of the one cutting blade 62 after the hole 22 is closed in this way. As a result, as shown in FIG.
As shown in FIG. 2 (b), it has a rectangular cross section and has two axial ends 2
A low melting point chip 20 in which 1a is tapered and closed is manufactured.

FIG. 4 is a perspective view showing an embodiment of the fuse of the present invention. In the figure, reference numeral 10 is a fusible body portion formed of copper, copper alloy, tin-plated copper, aluminum or the like, and caulking pieces 12 and 1 extending at a substantially central position in a direction perpendicular to the length direction.
A fusion-cutting portion 11 in which two pieces are connected in series is formed, and a low-melting point chip 20 manufactured by, for example, the above method (see FIGS. 3A and 3B) is crimped by the crimping pieces 12, 12. And is fixed. And the fusible body part 10
Both end portions in the length direction are bent downward substantially at right angles, and female terminal portions 30, 30 are connected to the lower end thereof.
The fusible body portion 10 and the low melting point chip 2 configured as described above
0, the female terminal portion 30 is housed in a housing (not shown) to form a block-type fuse.

In the fuse thus configured, when an abnormal current flows, the heat generated thereby melts the low melting point chip 20 and forms an intermetallic compound with the low melting point chip 20 in the fusing part 11.

Here, both ends 21a in the axial direction of the low melting point chip 20 (heat absorbing member 21) are closed, and the flux 40 is not exposed to the outside. Therefore, even if the powder-like compacted flux 40 is used, it does not fall outside during the assembly process. Further, even if the rosin-based flux 40 is used, it does not flow out because it absorbs moisture to become a liquid. Further, there is no possibility that the oxide film removing action is deteriorated by absorbing moisture from the outside air.

Therefore, the flux 40 is soluble in the fusible body portion 10 (fusing portion 1
1) or the oxide film on the surface of the low melting point chip 20 is sufficiently removed to activate the boundary surface between the fusing part 11 and the low melting point chip 20 to promote the formation of an intermetallic compound, and the effect of the low melting point chip 20 is sufficiently exerted. Therefore, it is possible to melt and melt at a temperature sufficiently lower than the red heat temperature of the fusible part 10.

In addition, since the flux 40 does not contain water,
When the low melting point chips 20 are melted, there is no problem that they are scattered around.

[Effects of the Invention] As described above, according to the fuse and the low melting point chip for a fuse of the present invention, the low melting point chip attached to the fusing part of the fusible body part is provided with the flux inside the chip made of the low melting point metal. And, since the entire surface of the flux is covered with a low melting point metal so that this flux is not exposed to the outside and sealed, the effect of the low melting point chip is not reduced,
Can be fused at low temperature. Further, there is no possibility that the low melting point chips will be scattered during the melting due to the water contained in the flux.

Further, according to the method of manufacturing a low melting point chip for a fuse of the present invention, a wire made of a low melting point metal in which a flux is arranged is applied to a cutting point by a pair of cutting blades facing each other while sandwiching the wire. A low melting point chip that cuts to a predetermined length and closes the cutting surface with the low melting point metal so that the internal flux does not leak and does not come into contact with the outside air, so that the effect does not decrease and it can be fused at a low temperature. To
It can be provided without requiring special equipment and at a low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of a low melting point chip for a fuse of the present invention, FIGS. 2 (a) and 2 (b) are perspective views showing the appearance, and FIG. FIGS. 4A and 4B are explanatory sectional views showing an embodiment of a method of manufacturing a low melting point chip for a fuse of the present invention, and FIG. 4 is a perspective view showing an embodiment of a fuse of the present invention. FIG. 5 is a perspective view showing a conventional technique, FIG. 6 is an explanatory sectional view for explaining a conventional method for manufacturing a low melting point chip, and FIG. 7 is a perspective view of a conventional low melting point chip. It is a figure. 10 ... Fusible body part 11 ... Fusing part 20 ... Low melting point chip 21 ... Chip 21a ... Axial both ends 30 ... Terminal part 40 ... Flux 60, 62 ... Cutting blade 61 ... Side surface 63 ... … Flat part

Claims (3)

[Claims] 1. In a fuse in which a low melting point chip is attached to a fusing part provided in a fusible body part, the low melting point chip is
A fuse characterized by arranging a flux inside a chip made of a low melting point metal, and covering the entire surface of the flux with the low melting point metal so as to prevent the flux from being exposed to the outside and sealing it. . 2. A low melting point chip arranged in a fusing part provided in a fuse melting body part, wherein a flux is arranged inside a chip made of a low melting point metal, and the flux is exposed to the outside. A low melting point chip for a fuse, characterized in that the entire surface of the flux is covered with a melting point metal and sealed. 3. A wire rod made of a low melting point metal having a flux disposed inside is cut into a predetermined length by squeezing the cutting point with a pair of cutting blades facing each other with the wire rod sandwiched therebetween,
A method of manufacturing a low melting point chip for a fuse, characterized in that the cut surface is closed with the low melting point metal so that the internal flux is not exposed to the outside.