JPH08321240A - Manufacture of current limiting fuse - Google Patents

Abstract

PURPOSE: To prevent wire severance of a soluble piece at the time of assembly by installing the soluble piece and an arc extinguisher in a cylinder and subjecting them to a hot joining process, to improve the easiness in works, stabilize the electric performance through making uniform the solder quantity on the joint surfaces at the time of soldering, and enhance the producibility. CONSTITUTION: A circular copper foil as a chip 1 for base board is fitted by pressure in one of the openings 2a in a cylinder 2 made of a heat resistant insulating material such as meramine resin or ceramics. One end of a soluble piece 3 is inserted from outside the central inserting hole 1b of the chip 1 which is fitted by pressure into the opening 2a, and the termination is bent and detained, and an arc extinguisher 4 is put in from the other opening 2b in the cylinder 2. Then the tip of the soluble piece 3 is inserted through the center hole 1b in another chip 1. The chip 1 is fitted by pressure in the opening 2b to seal the extinguisher 4, and the tip of the soluble piece 3 is folded and detained. A minute amount of adhesive 7 is applied to both ends of the cylinder 2 according to necessity, and an intruding force is given to the cylinder 2 in the direction of arrow using a jig B and a cup-shaped base metal piece 5 as melting of a solder disc 6 containing a necessary amount of flux at the inside bottom surface previously. At the same time as pressure fitting, heat is input and fast joining is established.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a fuse used mainly in an electric circuit of 600 V or less, particularly a fusible body is placed in an insulating cylinder together with an arc extinguishing agent, and both ends thereof are fixed to a cup-shaped base. The present invention relates to a method for manufacturing a current limiting fuse having a high breaking capacity.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, a current limiting fuse for an electric circuit of this type has the same outer diameter as the outer diameter of a tube (a) made of a heat-resistant insulating material and has a small hole at its center. Using the conductive washer (c) with (b), the fusible body (d) and arc-extinguishing agent (e) are filled inside the insulating tube (a), and the flux (f) and the adhesive (g) are enclosed together. It is known that a finished product as shown in FIG. 2 in which the solder (H) is covered with a cup-shaped base (R) for welding in advance and alternately heated by a hot plate A to bond and fix the same.

[0003]

As described in the prior art, in the manufacturing method shown in FIG. 1, a fusible body is formed in a state where both ends of the insulating cylinder are covered with conductive washers made of thin plates of good conductor metal. For soldering, if the rated current value is comparatively small, it is easy to break when a fusible body is a wire and a thin wire diameter is used, and it is necessary to hold the conductive washer body together with the fusible body with a finger when soldering. Therefore, the workability is poor, and as shown in FIG. 2, the conductive washer body has good solder wettability, so that the joint surface becomes uneven due to excessive solder diffusion that affects the effective length of the fusible body. When a fuse is blown at a low temperature load current, there is a large variation in the electrical fusing performance of the fuse, and for large currents such as short circuits, the higher the arc circuit voltage, the higher the arc circuit voltage. of There is concern that disables the blocking penetrates sometimes reach washer is a conductive metal end.

The present invention has been made in order to solve the problems caused by the above-described conventional manufacturing method, and a fusible body is provided in a central insertion hole of a circular copper foil board chip press-fitted into one end of a cylinder. Insert it, fill the arc extinguishing agent around it,
With the other end of the cylinder being press-fitted and sealed with a circular copper foil substrate chip and the tip of each fusible body inserted through the central insertion port being bent, the cup-shaped caps are covered from both ends of the cylinder and fixed. This prevents the fusible body from breaking during assembly, improves workability, and evens the amount of solder on the joint surface during soldering.
It is an object of the present invention to provide a method for manufacturing a current limiting fuse that stabilizes electrical performance and improves productivity.

[0005]

In order to achieve the above object, in the present invention, a thickness of 0.035 mm to 0.07 m is formed on one surface that matches the inner diameters of the openings on both sides of the cylinder.
m copper foil is electrodeposited, and a circular copper foil substrate chip having an insertion hole for inserting a fusible body in the center and a total thickness of 2 to 3 mm is press-fitted into one opening of the insulating cylinder, and this opening is formed. After sealing the meltable body through the central insertion port of the copper foil substrate chip and filling the arc-extinguishing agent from the other opening, this opening is press-fitted with the copper foil substrate chip and sealed in advance. A method for manufacturing a current limiting fuse, characterized in that a cup-shaped mouthpiece having a solder welded to an inner bottom surface thereof is press-fitted from both sides of the cylinder and heated at the same time to fix the same.

[0006]

[Function] The circular copper foil board chip press-fitted and sealed in the openings at both ends of the cylinder has an outer end because the end of the fusible body inserted through the central insertion opening is almost in plane contact with the copper foil plate by bending. A reliable joint can be obtained at the inner bottom surface of the cup-shaped die that is press-fitted from.

In the manufacturing process as well, after the arc extinguishing agent is filled in the cylinder, the openings at both ends of the cylinder can be completely sealed with the circular copper foil substrate chips, so that the arc extinguishing agent does not leak at all. It can have a closed shape.

Further, even in the step of covering the cup-shaped mouthpiece from the outside of the cylinder and fixing it, it is not necessary to alternately heat the fusible body and the conductive washer with fingers as in the conventional case, so that the workability is extremely efficient. And productivity is improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the manufacturing method of the present invention will be described below with reference to the drawings. In FIG. 3, 1 is a copper foil 1a having a thickness of 0.035 mm to 0.07 mm only on one surface.
FIG. 2 is a perspective view of a circular copper foil substrate chip that has been electrodeposited, has the remainder as an insulating material 1c, and has a through hole 1b in the center and a total thickness of 2 to 3 mm and is pressed to the same outer diameter as a cylinder. is there.

FIG. 4 is a sectional view showing the steps of the method for manufacturing a current limiting fuse according to the present invention. In FIG. 4 (a), a tube made of a heat-resistant insulating material such as melamine resin or ceramic. 1 through the opening 2a on one side of FIG.
Then, the circular copper foil substrate chip is pressed in as shown in FIG.

Next, as shown in FIG. 1C, one end of the fusible body 3 is inserted from the outside of the insertion hole 1b at the center of the circular copper foil substrate chip 1 press-fitted into the opening 1a, and the end is bent to engage. Then, the arc extinguishing agent 4 is filled from the other opening 2b of the cylinder 2.

Subsequently, as shown in FIG. 1D, the tip of the fusible body 3 is inserted into the insertion hole 1b at the center of the circular copper foil substrate chip 1, and the arc-extinguishing agent 4 is press-fitted into the other opening 2b of the cylinder 2. And the tip of the fusible body 3 is bent and locked as shown in FIG.

Further, as shown in FIG. 2 (f), the solder disk 6 in which a required amount of flux has been contained in advance on the inner bottom surface is melted while the rare adhesive 7 is applied to both ends of the cylinder 2 as required. Using a jig B equipped with a cup-shaped base 5 and a heating device capable of holding the cup-shaped base 5, a pressing force is applied to the cylinder 2 in the direction of the arrow shown in the figure, and the cylinder 2 is heated and pressed at the same time to bond and fix.

FIG. 5 is a sectional view of the current limiting fuse of the present invention completed through the above manufacturing steps. As shown in this figure, the fusible body 3 and the cup-shaped caps 5 at both ends are joined together. The state is securely joined via the solder 6 on the inner bottom surface of the cup-shaped base 5 and the copper foil portion 1a of the circular copper foil substrate chip 1 press-fitted into both ends of the tube 2.

[0015]

Since the present invention is constituted by the manufacturing method as described above, it has the following effects.

A fusible body and an arc-extinguishing agent are arranged inside the cylinder, the openings at both ends of the cylinder are sealed with circular copper foil substrate chips, and the cup-shaped mouthpiece is covered from the outside and heated at the same time as press-fitting. Since the process of joining and fixing is made extremely easy.

The amount of solder for soldering the fusible body to the cup-shaped mouthpiece can be freely adjusted by the size of the insertion hole of the circular copper foil substrate chip and the volume of the solder disk, and therefore can be always quantified. Moreover, the joined state is also finished neatly.

As in the conventional case, the overall length of the cylinder to be soldered from the inside must be considered in consideration of the dimensions including the thickness of the conductive metal fittings. The dimensions of the tubes to be soldered from the inside could not be used in common, though the diameters were the same), and a tube with at least two total length dimensions had to be required. However, by pressing the circular copper foil substrate chip into the opening of the cylinder as in the case of the present invention, considering the size of the cylinder to be soldered from the outside, it is irrelevant to the overall length of the cylinder. Since the length of the fusible body soldered on the outside of the tube and the size of the fusible body soldered from the inside can be the same, only one type of tube, which is commonly used, is sufficient.

Since the back surface of the circular copper foil substrate chip used in the present invention is an insulating material, at the time of heat-bonding with a cup-shaped die through a fusible body, unlike the conventional metal conductive washer, the whole is due to heat conduction. Since the heat storage property is low, the solder and the flux that melt at the time of joining flow only to the copper foil side of the circular copper foil substrate chip and can be completely welded and joined to the cup-shaped die.

At this time, since the conductive washer is not used, there is no excess solder flowing into the effective length side of the fusible body, and the effective length of the fusible body is 100% utilized. The variation of can be greatly reduced.

Also, in the case of interruption due to the passage of a short-circuit large current, which is the characteristic feature of the current limiting fuse, when the arc is promoted, the insulator of the circular copper foil substrate chip press-fitted and sealed at both ends of the cylinder becomes the stopper. By playing a role, the duration of the arc can be suppressed.

Further, in the manufacture of a current limiting fuse using a ceramic having a mechanical strength in a cylinder, a cup-shaped mouthpiece having a diameter equal to or slightly smaller than the both ends of the cylinder is directly applied to a predetermined pressing force without using an adhesive. It can also be manufactured by press-fitting and heating for a short time.

[Brief description of drawings]

FIG. 1 Method of manufacturing a conventional current limiting fuse

2 is a sectional view of a current limiting fuse completed by the manufacturing method of FIG.

FIG. 3 is a perspective view of a circular copper foil substrate chip used in an embodiment of the present invention.

FIG. 4 is a method of manufacturing a current limiting fuse of the present invention.

5 is a sectional view of a current limiting fuse completed by the manufacturing method of FIG.

[Explanation of symbols]

1 circular copper foil substrate chip 2 cylinder 3 fusible body 4 arc extinguishing agent 5 cup-shaped base 6 solder 7 adhesive A hot plate
B jig

Claims (1)

[Claims] 1. A current limiting fuse comprising a tube made of a heat-resistant insulating material, a fusible body arranged in the tube, and both ends of the tube fixed from outside with metal cup-shaped caps. Electrodeposited a copper foil with a thickness of 0.035 mm to 0.07 mm on one surface that matches the inner diameter of the openings on both sides, and has a through hole for inserting the fusible body in the center to a total thickness of 2 to 3 mm. The circular copper foil board chip is press-fitted into one of the openings of the cylinder, the opening is sealed and a fusible body is inserted through the central insertion opening of the circular copper foil board chip, and the other opening is further provided. After filling with an arc extinguishing agent, this opening is press-fitted and sealed with a circular copper foil substrate chip, and a cup-shaped mouthpiece with solder previously welded to the inner bottom surface is heated at the same time as press-fitting from both sides of the cylinder. A current limiting fuse characterized in that Manufacturing method.