KR930004698Y1 - Subminiature fuse - Google Patents

Abstract

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Description

Micro Fuse

1 is a perspective view of a micro fuse according to an embodiment of the present invention.

2 is a cross-sectional view of the cut portion of the ultra-small fuse shown in FIG.

Figure 3 is a cross-sectional view of the cut portion of the ultra-fine fuse according to another embodiment of the present invention.

4 and 5 are views showing a method for assembling the micro fuses shown in FIGS. 1 to 3 according to an embodiment of the present invention.

The present invention relates to a very small fuse.

In recent years, electronic devices are becoming smaller and smaller, and as a result, the components of electronic circuits are becoming smaller and smaller. In addition, as the 200V wiring of general households is progressing with respect to the withstand voltage, there is an increasing demand for a small fuse that can be used for a printed circuit board from a low voltage of several volts (V) level to a high voltage exceeding AC 125V.

Various types of small fuses have been developed to meet this need. One example of the small fuse developed so far is that the shape of the resin filled around the fuse wire is useful, making it easy to miniaturize. However, this type of fuse loses Joule heat to the resin around the fuse line when a relatively small overcurrent due to a transistor breakdown, etc. causes the melt time to be delayed or a sufficient number of elements are damaged to blow the fuse. It has a flaw that does not melt until it flows. If the fuse line is completely enclosed by the resin when a large current of more than AC 125V flows due to a short circuit, there is no place to release metal vapor generated by melting, evaporation, or expanded metal components caused by the large current. . As a result, the arc time was delayed, causing a potential risk of rupturing and scattering of the resin around the fuse line.

In order to solve the problem pointed out above, a small pupe has been developed that can be filled with an arcextinguishing agent around the fuse line to protect the resin from breakage by a large current. However, as with the above-mentioned fuses, in the case of a small overcurrent, the problem that the fuse line is not melted without excessive large current flow due to deprivation of Joule heat by the anti-corrosive agent was developed as mentioned above. Small fuses were of low reliability.

Accordingly, an object of the present invention is to solve the above-mentioned general problems, to be very small without the use of an anti-foaming agent, to provide a high breaking performance, and to quickly melt the fuse wire when an abnormal current flows to the associated circuit and It provides ultra-small fuses with the ability to protect components and reduce fluctuations in meltdown time for improved reliability.

It is an object of the present invention to provide a housing with two sealed SOHO chambers adapted to extinguish an arc and a small hole in which the two SOHO chambers communicate with each other, and from an external surface of the housing to determine an external connection adapted for connection to an external electronic circuit. A pair of conductive terminal members mounted in the housing with one end of the pair of terminal members extending outwardly, and two ends of the pair of internally extending terminal members respectively in two sub-chambers in the housing, and a pair of terminal members having both ends It is intended to obtain a very small fuse made of a fusible element adapted to be electrically and mechanically coupled to the other end of the circuit, whereby the circuit can be blocked by SOHO without the use of an anti-foaming agent and the free-arcing time-current characteristics of the fuse. Can be reduced.

In a preferred embodiment of the present invention, the housing is composed of an upper member having a recess and a partition and a lower member for dividing the recess. The conductive terminal member pair is attached to the lower member and has the other end of the pair of terminal members extending from the upper surface of the lower member to determine an external connection connected to an external electronic circuit. The lower member provides a partition projecting upward from the upper surface of the lower member to divide the terminal member pair. The upper member is engaged with the lower member having a concave portion facing downward from the upper surface of the lower member, and the partition of the upper member determines the two sealed SOHO chambers, each containing the other end of each pair of terminal members. Provided to the mesentery.

The lead frame is provided by press working, and has a comb shape in which ends of the plurality of terminal arrangements are continuously connected to the tips of the protrusions shaped like a comb.

Each set of terminal members provided in the lead frame is fixed to the lower member, and consists of two terminal members when the lower member is molded into resin by casting, and at the tip of a series of terminal members protruding from the upper surface of the lower member. Elongated fuse line is extended. The leading end of the terminal member is folded and overlapped to fix the fuse wire, and is firmly soldered immediately after. The fuse line is then cut at a position between adjacent terminal members of each neighboring set of terminal members.

The upper member having a small semi-circular concave portion at the center of the tip of the partition is engaged with the lower member at the side of the fuse line fixed to the lower member, and adjacent portions of the upper and lower members are welded together by ultrasonic welding. The tip of the upper member and the lower member are welded together, and the tip and the lower member of the side wall defining the recess in the upper member are welded together so that the two arc chambers receive the ends of the pair of terminal members for fixing the fuse line respectively. Is formed.

The fuse line extending between the tip portions of the terminal member pairs keeps floating in the air in a small semicircular concave portion provided in the partition of the upper member without contacting the partition of the upper and lower members. Such equipment does not lose Joule heat even when overcurrent occurs, and the fuse can always be melted quickly.

Moreover, even if arc is generated after the fuse line is melted, the metal vapor which generates arc will be limited to a small hole made in a small semicircular recess.

In this way, it is difficult for the arc to splash between the terminal members, thereby facilitating extinguishing. In addition, it is possible to reduce the occurrence of arc by increasing the dielectric strength between the terminal members by dividing the arc with the diaphragm of these two arc chambers. When welding of the upper and lower members is completed, the end of the terminal member at the terminal member side connected to the comb-shaped protrusions is cut to provide an individual fuse.

According to another embodiment of the present invention, as a fuse for a voltage of AC 125V or higher, a pair of terminal members for fixing a fuse wire to double the distance between the fuse and the terminal member connected to the fuse and to have a high breaking performance. A fuse is provided in which one or more SOHO chambers are provided between two SOHO chambers each containing one end. If a comb-shaped lead frame having a continuously connected terminal member is used for fuse assembly, fixing the terminal member to the lower member by casting molding, fixing the fuse wire to the tip of the terminal member, the upper and lower members By continuously performing the step of welding, mass production can be performed at a low manufacturing cost. These objects and advantages of the present invention will become more apparent by creating the accompanying drawings and claims.

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1 is a perspective view of one embodiment of a micro fuse according to the present invention. The ultra-small fuses are of very small shape with dimensions of approximately 5 mm (width, thickness) and 6.5 mm (height).

FIG. 2 is a cross-sectional view of the micro fuse shown in FIG. 1, which is a cutout that clearly shows the internal structure of the fuse.

With reference to FIGS. 1 and 2, the housing 10 consists of an upper member 12 and a lower member 14. In more detail, the two members are joined so that the two arc chambers 18 and 20 are determined in the housing and connected to each other through the small holes 16.

Lead terminals 22 and 24 made of conductor material are secured in the lower member 14 made of an electrically insulating material. One end of the lead terminals 22, 24 protrudes from the lower surface of the lower member to provide an external connection 26, 28 connected to an external electrical circuit, while the other end of the lead terminals 22, 24 is connected at the tip end. It protrudes from the upper surface of the lower member 14 to provide the connecting portions 30 and 32 for connecting the fuse line. The fuse wire 34 extends between the fuse wire connection portions 30 and 32 of the pair of lead terminals 22 and 24.

Both ends of the fuse wire 34 are electrically connected to the fuse wire connecting portions 30 and 32 and mechanically fixed. Fuse wire connecting portions 30 and 32 are preferred, in which the tip portion is folded and overlapped to fix both ends of the fuse wire and securely fixed by soldering therebetween. The lower member 14 has a partition 36 projecting upward from the center of the upper surface of the lower member 14 to separate the fuse wire connecting portions 30 and 32 of the lead terminals 22 and 24, The tip end surface is slightly lower than the height of the extended fuse line 34 so as not to contact the fuse line 34.

A stepped portion 38 is provided on the side of the lower member 14. It is preferable that the lower member is molded into resin by casting, and at the same time, the central portions of the lead terminals 22 and 24 are fixed in the lower member 14.

The upper member 12 includes a recess 40 and a partition 40 extending downward from the upper inner surface of the recess so that the recess is separated into two parts. A small, concave portion of semi-circular shape is provided toward the center at the tip surface of the membrane 40.

When the upper and lower members 12 and 14 are engaged with the recesses of the upper member 12 which are directed toward the lower member side from which the fuse wire connecting portions of the lead terminals 22 and 24 protrude, the recesses of the upper member 12 The tip of the side wall to be determined is suitably fitted with respect to the end portion 38, and the partition 40 of the upper member 12 is aligned with the partition 36 of the lower member 14, thereby forming both partitions 36 and 40. The leading end faces of) are adjacent to each other.

The upper member 12 is assembled in this way.

After the upper member 12 and the lower member 14 are combined in the same manner as described above, the front end of the side wall that determines the recess of the upper member, and the partitions 36 and 40 of the upper member 12 and the lower member 14. The end face 38 of the lower member 14, as well as the adjacent surface of c), are welded together by ultrasonic welding. Thus, the semicircle of the part formed by the arc chambers 18 and 20 which accommodate the fuse wire connection parts 30 and 32 of each lead terminal 22 and 24, and the recessed part 42 of the upper member 12, respectively. A small hole 16 on the top and a portion of the front end face of the partition 36 of the lower member 14 are provided. The fuse line 34 extends through the small hole 16 without contacting the inner wall of the hole 16 and remains in the air. Due to the above-described structure in which the fuse line is kept in the air without being completely in contact with the upper member 12 and the lower member 14, the Joule heat is transferred to the upper member even though a small abnormal current flows through the fuse line. 12) and the lower member 14, the fuse can be melted quickly and can be secured to protect external components and circuits from abnormal current. In addition, even if a large current exceeding AC 125V causes arcing, such arcs are cleaved by the separation of the partitions 36 and 40 of the upper member 12 and the lower member 14, thereby increasing the insulation strength and providing high breaking performance. You can get it.

3 is a cross sectional view of a micro fuse used for a circuit using a voltage of AC 125V or higher. Similar components described in connection with FIG. 2 are denoted by the same reference numerals. Compared with the embodiment shown in FIG. 2, the difference is that two SOHO chambers 44 have two membranes for SOHO chambers in which each fuse wire connection portion 30, 32 of the lead terminals 22, 24 is housed. It is installed between. Thereby, a high blocking performance can be further achieved.

4 and 5 illustrate some of the steps of assembling the fuse according to the embodiment of the present invention. The comb-shaped lead frame 46 in which the external connecting portions 26 and 28 of the plurality of lead terminals 22 and 24 are continuously connected at the tips of the protrusions of the comb-shaped lead frame 46 is prepared in advance by pressing. do.

The ends 48, 50 of the fuse wire connecting portions 30, 32, which are applied to firmly fix the fuse wires 34 of the lead terminals 22, 24, are bent in the "L" shape by press working. It is done. Both ends of the bends 52, 54 are provided in narrow portions 56, 58 to facilitate bending. Grooves 60 and 62 are formed in the center of the narrow portions 56 and 58 so that the L-shaped ends 48 and 50 of the fuse line connecting portions 30 and 32 are folded and folded around the fuse line 34. It is provided to protect the fuse line 34 from damage when compressed to contact the fuse line. The L-shaped bends 52 and 54 are bent in a U shape so that the fuse wire 34 is retained after the fuse wire 31 is provided and securely fixed by soldering. The extension, fixation, and assembly of the fuse wire 3B can be performed using a continuous lead frame, thereby enabling mass production. Immediately after each part of the fuse wire 34 extended between the terminal members fixed by casting molding to the adjacent lower member, respectively.

The upper member is suitably fitted to the lower member 14 together with the recess of the upper member 12 directed toward the lower member 14 to which the fuse line 34 is fixed, and the upper member 12 and the lower member 14 are fitted. Adjacent parts of) are welded together by ultrasonic welding.

Then, the stages of the external connections 26, 28 of the terminal members 22, 24, which are continuously connected to the comb-shaped protrusions of the comb-shaped leadframe 46, are prepared to provide individual fuses.

Instead of providing the recessed portion 42 of the partition 40 of the upper member 12, the recessed portion may be formed into the partition 36 of the lower member 14 or both partitions of the lower and upper members 14, 12 ( 36, 40 may be provided.

As described above, the present invention has an effect that can be mass-produced at low cost, with excellent cut-off performance and low fluctuation of the response time even at high voltage of AC 125V or more by installing SOHO chamber.

Claims (5)

A housing having two closed arc chambers adapted to arc the arc and a small hole for communicating the two arc chambers with each other; An opposing constitution comprising an end of a pair of terminal members extending outward from an outer surface of the housing to define an external connection to be connected to an external electrical circuit and the other ends of the pair of terminal members each extending into the two arc chambers of the housing; A pair of conductive terminal members having an end portion and fixed to the housing; Fusible with opposing ends and extending through the small holes provided in the housing in a manner so as to be spaced apart from the inner wall of the small holes, the opposing ends being electrically and mechanically connected to the other ends of the pair of terminal members respectively; An elementary fuse, characterized in that the circuit can be interrupted by extinguishing without the use of an extinguishing agent, and the fluctuations in the melting properties of the fuse can be reduced. 2. The method of claim 1, wherein one or more closed arc chambers are additionally disposed in series between the pair of arc chambers in the housing, and the one or more additional arc chambers are in communication with the pair of arc chambers continuously through the small holes. And extend through the small hole and the added one or more arc chambers in a manner such that the soluble element is spaced apart from the inner wall of the small hole. The micro fuse of claim 1, wherein the housing is made of resin, and the terminal member pair is fixed to the housing by casting the housing. 2. The housing of claim 1, wherein the housing includes a lower member and an upper member to which the terminal member pair is fixed and having a partition for separating the other end of the terminal member pair; The upper member has a recess separating the recess and the recess, and when the upper member and the lower member are coupled to each other, the partition of the upper member is arranged adjacent to the partition of the lower member. And a concave portion of the upper member adjacent to the partition of the lower member provided on its surface to connect the SOHO chamber pair and to form the small hole such that the fusible element extends through the hole. Tiny fuse made with. The micro fuse according to claim 4, wherein a cross-sectional shape of the concave portion is semicircular.