JP2000251610A - Micro-fuse inserted in substrate and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuse which prevents a fuse construction from being destroyed by reducing and eliminating arc energy through the method of fixing a terminal lead to an insulation base, instead of using an insert injection method of high cost. SOLUTION: This microfuse comprises a base 110 with two openings, leads 120, 130 fitted to the openings of the base 110, a fusible body 140 soldered to the leads 120, 130, wherein the openings are formed in an eleptical shape, terminal ends of the leads 120, 130 are formed into an elliptical shape under a compressed state, with a specified thickness and insertion fitted in the openings 120, 130, and the microfuse has a cap 100 with a recessed groove 100a engaged with an engaging flange 112 of the base to shut out the inside of the base 110 from the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microfuse for inserting a substrate, and more particularly to a fuse or a protector which is indispensable as a safety protection element for a product in accordance with the necessity of miniaturization of internal parts due to reduction in size and weight of electronic products. The present invention relates to a board-inserting microfuse made to be directly mounted on a circuit board of a mother product in order to cope with the trend of the trend, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A microfuse is a device mainly used for a printed circuit board, but is required to be physically small. Such a microfuse happens to cut off a surge current in an extremely short transient time. Must be designed. Currently used fuses have two leads connected to both ends of a fusible body fixed to a plastic base at the center of the lead, and the two opposite ends of the fixed lead are inserted into holes of a printed circuit board. In order to achieve this, a lead and base integrated part is manufactured using a method commonly known as insert injection, and then the fuse is assembled.

[0003]

However, according to the insert injection method, a lead cut to a predetermined length is attached to a specially manufactured precision ultra-small injection mold, and then this mold is further attached to an injector. Since it must be mounted and plastic injected, the production cost of this special mold is high,
This is inefficient because the life is short and the productivity per hour is significantly inferior to that of general injection.

[0004] Furthermore, regarding the reliability problem, which is an important key from the viewpoint of the production of electronic products, insert injection significantly reduces the solderability of the leads, resulting in a great loss of the reliability of the entire product. There is. However, in spite of these problems, if the leads are not firmly fixed to the base, the movement of the leads will lead to a reduction in the role of the product and the overall reliability, so the leads must be fixed firmly. The problem is that the use of an insert injection method is inevitable.

The present invention has been devised to solve the above-mentioned problems, and replaces a high-cost insert injection method by fixing a terminal lead to an insulating base in a method of manufacturing a microfuse for inserting a substrate. Accordingly, it is an object of the present invention to provide a microfuse for substrate insertion and a method for manufacturing the same, which reduce arc energy and prevent a fuse structure from being destroyed.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a base having two openings, a lead mounted in the opening of the base, and a solderable lead. Wherein the opening is formed in a conical shape, and the terminal end of the lead is formed in an elliptical shape in a state of being pressed to a predetermined thickness, and the conical opening is formed. And a cap having a concave groove that is inserted and mounted in the portion and that is fitted with a fitting flange of the base to block the inside of the base from the outside.

In order to manufacture a microfuse according to the present invention, a base having two conical openings is injection-molded and a cap is injection-molded; Inserting a lead prepared beforehand into the opening of the base;
Squeezing a predetermined portion of the terminal end to a predetermined thickness to fix the lead inserted in the lead insertion step to the base to form an elliptical squeezed portion; and forming the squeezed portion. A fixing step of soldering and fixing a previously prepared fusible body to the end of the squeezing portion; and mounting in which the fusible body is fixed to the lead in the fixing step until both leads are mounted on the base. And a completion step of: when the lead is mounted on the base, inserting a protrusion of the base into a concave groove of a cap to complete a product.

Further, in order to manufacture a microfuse according to the present invention, an injection molding step of injection molding a base having two conical openings and an injection molding of a cap; Inserting a lead prepared in advance into the opening of the base; and pressing a predetermined portion of the terminal end to a predetermined thickness in order to fix the lead inserted in the lead inserting step to the base. A pressing step of forming an oval-shaped pressing portion; a mounting step of pulling both leads having the pressing portion formed in the pressing step until the lead is mounted on the base; A fixing step of soldering and fixing a previously prepared fusible body to the ends of both leads; and a projection on the base in a state where the fusible body is fixed to the lead in the fixing step. It is characterized with a complete step to complete the product is inserted into the groove portion of the cap.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a structure and a manufacturing method of a microfuse for inserting a substrate according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. First, FIG.
The structure of the micro fuse according to the present invention will be described with reference to FIGS.

[0010] Cap 100 made of plastic injection material
And a concave groove 100a formed on the inner peripheral surface of the cap 100,
Base 110 made of plastic injection material and has insulating function
And a pair of openings 110a, 110 formed in the base 110.
b, a pair of leads 120, 130 inserted into the openings 110a, 110b, respectively, and a fusible body 140, which is fixed by soldering to the end of the leads 120, 130 and melted when an overcurrent flows, Become.

[0011] The leads 120 and 130 are formed by pressing the pressing portions 120a and 130a which are squeezed in an elliptical shape so as to have a predetermined thickness at the end portions.
Consists of The openings 110a and 110b of the base 110 are formed in a conical shape so as to have a predetermined space when the pressing parts 120a and 130a of the leads 120 and 130 are inserted and mounted. The base 110 includes a separation adjusting protrusion 114 at a lower end thereof to maintain a space between the leads 120 and 130.

Further, the base 110 and the cap 100 are
It can be manufactured by selecting a square and a circle. FIG. 4 shows a method of manufacturing a microfuse having the above structure.
The following is a description with reference to FIG. First, the plastic base 110 and the cap 100 are injection-molded (S
1).

At this time, the base 110 to be injection molded is 2
One opening 110a, 110b is formed, the openings 110a, 110b are formed in a conical shape, and a concave groove 100a is formed inside the cap 100. When the base 110 and the cap 100 are molded in S1, a wound type fuse fusible body 140 and leads 120, 130 in which a fusible body corresponding to the rated current is wound around the outer peripheral surface of the asbestos thread are prepared.

The openings 110a, 1 of the base 110 molded in S1
After inserting and penetrating the leads 120, 130 prepared in advance into 10b (S2), the leads 120, 130 inserted in S2 are connected to the base 11
In order to fix to 0, a certain portion of the lead end portion is squeezed to a predetermined thickness to form elliptical squeezed portions 120a, 130a
(S3). The fusible body 140 is soldered to the ends of the lead squeezed portions 120a, 130a squeezed in S3, and the fusible body 140 and the leads 120, 1 are soldered.
30 is fixed (S4).

With the leads 120, 130 and the fusible member 140 fixed in S4, physical force is applied to both the leads 120, 130 until they are attached to the base 110 using scissors (eg, pneumatic scissors). Then, the leads 120 and 130 are pulled to compress the elliptical compressed portions 120 and 130 into the openings 110a and 110b so that the compressed portions 120 and 130 are attached to the openings 110a and 110b (S5). Thereafter, the fitting flange 112 of the base 110 is fitted into the concave groove 100a formed on the inner surface of the cap 100 and inserted so as to be fixed in position, thereby completing the product (S6).

Note that (S4) and (S5) may be reversed.

[0017]

As described above, according to the present invention, it is not necessary to use the insert injection method having the highest cost ratio in the manufacturing process of the insulating base for fixing the lead, so that the manufacturing cost can be reduced, and the inner wall of the base hole and the lead can be reduced. This is a very effective invention in the electric and electronic parts manufacturing industry, since it has a function of forming a space between them to significantly reduce the air pressure expanded by the arc energy and improving short-circuit breaking performance.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a microfuse according to an embodiment of the present invention.

FIG. 2 is a schematic exploded perspective view of a micro fuse according to an embodiment of the present invention.

FIG. 3 is a sectional view of a micro fuse according to one embodiment of the present invention.

FIG. 4 is a flow chart relating to the microfuse manufacturing method of the present invention.

[Explanation of symbols]

 100 Cap 100a Concave groove 110 Base 110a, 110b Opening 112 Mating collar 114 Separation adjusting protrusion 120, 130 Lead 120a, 130a Squeezed part 140 Soluble

Claims (3)

[Claims] 1. A board-inserting microfuse comprising: a base having two openings; a lead mounted in the opening of the base; and a fusible member soldered to the lead. Is formed in a conical shape, and the end of the lead is formed into an elliptical shape in a state of being squeezed to a predetermined thickness, and is inserted and mounted in the conical opening, so as to block the inside of the base from the outside. And a cap having a concave groove fitted with the fitting flange of the base. 2. An injection molding step in which a base having two openings formed in a conical shape is injection-molded, and a cap is injection-molded; and a lead prepared in advance in an opening of the base molded in the injection molding step. Inserting a lead;
Squeezing a predetermined portion of the terminal end to a predetermined thickness to fix the lead inserted in the lead insertion step to the base to form an elliptical squeezed portion; and forming the squeezed portion. A fixing step of soldering and fixing a previously prepared fusible body to the end of the squeezing portion; and mounting in which the fusible body is fixed to the lead in the fixing step until both leads are mounted on the base. And a step of inserting the protrusion of the base into the concave groove of the cap when the lead is mounted on the base to complete a product, the method comprising the steps of: 3. An injection molding step in which a base having two openings formed in a conical shape is injection-molded, and a cap is injection-molded; and a lead prepared in advance in the opening of the base molded in the injection molding step. Inserting a lead;
Squeezing a predetermined portion of the terminal end to a predetermined thickness to fix the lead inserted in the lead insertion step to the base to form an elliptical squeezed portion; and forming the squeezed portion. A mounting step of pulling both leads having a squeezed portion until the leads are mounted on the base; and fixing the prepared fusible material to the ends of the both leads by soldering when the leads are mounted on the base. A step of inserting a protrusion of a base into a groove of a cap with the fusible body fixed to the lead in the fixing step to complete a product, the microfuse being inserted into a substrate. Production method.