JPH0572033U - Chip fuse - Google Patents

Abstract

(57) [Summary] [Object] To provide a chip fuse having a structure capable of reliably electrically connecting a conductive terminal and a fusible body by preliminary soldering during assembly. A pair of fusible body through-grooves 20 are provided on the side surfaces near both end surfaces 16 of a main body 10 of a prismatic body having a through hole 18, a fusible body 14 is stretched in the through hole, and both ends thereof are flexible. It is locked in the melt passage groove. The conductive terminal 12 preliminarily soldered 24 into the recess 22 is press-fitted from the end surface of the main body while being heated. At this time, the heated and expanded air in the through hole is discharged by the air vent notch 26 formed so as to communicate with the through hole from the side surface of the main body. Therefore, the melted solder is not pushed out from the fitting portion between the conductive terminal and the side surface of the main body, and the conductive terminal and the fusible body are reliably soldered.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a chip fuse, and more particularly, to a structure for securely performing electrical connection between a fusible body and a conductive terminal portion by preliminary soldering when assembling a fuse.

[0002]

[Prior Art]

 As a conventional chip fuse, one having a structure as shown in FIG. 6 is known (see, for example, Japanese Utility Model Laid-Open No. 64-56135).

[0003]

[Problems to be solved by the device]

 In FIG. 6, 10 is a prismatic body, 12 is a conductive terminal, and 14 is a fusible body. The main body 10 is provided with a through hole 18 penetrating between the both end surfaces 16 thereof and a fusible body through groove 20 on the side surface of the both end surfaces 16. The conductive terminal 12 has a recess 22 fitted in the side surfaces of both end surfaces 16 of the main body 10, and an inner surface of the recess 22 is provided with preliminary solder 24. This chip fuse is assembled as follows. The fusible body 14 is passed through the through hole 18 of the main body 10, and both ends of the fusible body 14 are locked in the fusible body passing groove 20. Next, while the one conductive terminal 12 is being heated, the concave portion 22 of the conductive terminal 12 is fitted from one end face 16 of the main body 10 along the side surface thereof, and the concave portion 22 of the conductive terminal 12 is The inner surface and one end of the fusible body 14 are soldered. Further, similarly, the other conductive terminal 12 is fitted from the other end face 16 and the inner surface of the recess 22 of the conductive terminal 12 and the other end of the fusible body 14 are soldered to complete the chip fuse.

Here, when the other conductive terminal 12 is fitted to the other end surface 16 of the main body 10, since the conductive terminal 12 is heated, the air in the through hole 18 of the main body 10 is also heated. The expanded air pushes out the melted preliminary solder 24 from between the side surface of the recess 22 of the fitted conductive terminal 12 and the side surface of the main body 10. Therefore, the conductive terminal 12 and the fusible body 14 may not be reliably soldered, which causes a problem such as a decrease in yield or a decrease in reliability.

The present invention has been made in view of the above problems, and an object thereof is to provide a conductive terminal fitted in a main body having a through hole and a fusible body stretched in the through hole. The purpose is to provide a chip fuse with a structure that can be reliably electrically connected by pre-soldering during assembly.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the chip fuse of the present invention is a main body made of a heat-resistant insulating material and having a shape of a columnar body, and a through hole penetrating between both end faces in the longitudinal direction thereof and the end faces of the both end faces. A main body having an outer peripheral surface of at least one end surface and an opening communicating with the through hole, and a fusible body stretched over the through hole, each end of which is the outer peripheral surface in contact with the both end surfaces. A fusible body that extends along the surface and is locked, and a concave portion that is fitted to the outer peripheral surfaces of the both end surfaces, and when fitted, the concave portion and the end portion of the fusible body Are electrically connected via preliminary solder, and the recess includes a pair of conductive terminal portions that cover the opening of the main body.

[0007]

[Action]

 The chip fuse configured as described above is assembled in the same process as the above-described conventional chip fuse assembly. However, in the step of fitting the pair of conductive terminals to the main body, the fitting on the side having the opening is performed last. The air in the through-hole of the body also heats and expands during the process in which the recess of the conductive terminal that is heated enough to melt the preliminary solder is fitted along the side surface from the end surface on the side with the opening of the body However, the expanded air is released to the outside through the opening. Therefore, the expanded preliminary air does not push the melted preliminary solder from the mating surface between the recess of the conductive terminal and the side surface of the main body, so the conductive terminal and the end of the fusible body can be reliably connected by the preliminary solder. Be touched.

[0008]

【Example】

 Preferred embodiments of the present invention will be described below with reference to the drawings. The components designated by the same reference numerals as those in FIG. 6 have the functions corresponding to those of the conventional chip fuse shown in FIG.

FIG. 1 is a perspective view of a completed chip fuse of the present invention. In FIG. 1, 10 is a main body and 12 is a pair of conductive terminals.

FIG. 2 is a perspective view of the body 10 shown in FIG. The main body 10 is made of, for example, a heat-resistant insulating material such as ceramic, has a prismatic shape, and has a cylindrical through hole 18 penetrating between the both end faces 16 along the longitudinal direction thereof. In the main body 10, a fusible body through groove 20 is formed in a diagonal position on opposite side surfaces in the vicinity of both end surfaces 16 of the main body 10. Both sides from the side surface facing the side surface where the fusible material through groove 20 is provided to the through hole 18 A slit-shaped air vent notch 26 is formed along the surface 16.

FIG. 3 is a component configuration diagram of the chip fuse shown in FIG. 1 before assembling. In FIG. 3, reference numeral 14 designates a fusible body having an elongated shape. FIG. 4 is a cross-sectional view of the chip fuse after the components of the chip fuse shown in FIG. 3 have been assembled, as seen from a plane including the fusible body 14, the fusible body passing groove 20, and the air vent notch 26. At the time of assembly, the fusible body 14 is stretched through the through holes 18 of the main body 10, and both ends of the fusible body 14 are locked in the respective fusible body passage grooves 20 of the main body 10. The conductive terminal 12 is composed of, for example, a base terminal, has an outer shape of a rectangular parallelepiped, and has a recess 22 on one surface thereof, which is fitted from the end surface 16 of the main body 10 along the side surface thereof by press fitting. When the conductive terminal 12 is press-fitted, the fusible body through groove 20 damages the end of the fusible body 14 by the inner wall of the recess 22 and the side surface of the main body 10, or extends the fusible body 14 in the press-fitting direction. It works to prevent this. Preliminary solder 24 is applied to the inner surface of the recess 22. The conductive terminal 12 has a function of electrically connecting to an external circuit on the printed circuit board, and four outer surfaces of the conductive terminal 12 which are orthogonal to the recessed portion 22 form a surface to be mounted on the printed circuit board. .. One of the conductive terminals 12 is heated so as to melt the preliminary solder 24, and the recess 22 thereof is press-fitted from one end face 16 of the main body 10 on which the fusible body 14 is stretched along the side face thereof. The recess 22 of the conductive terminal 12 and the end of the fusible body 14 are soldered by the preliminary solder 24 and electrically connected. At this time, the air in the through hole 18 of the main body 10 is also heated and expanded by the heated conductive terminal 12, but since the other end face 16 side of the through hole 18 is open, the expanded air escapes from there. Next, the other conductive terminal 12 is press-fitted from the other end surface 16 of the main body 10 in the same manner as the previous conductive terminal 12, while being heated. At this time, the air in the through-hole 18 of the main body 10 is heated and expanded by the other heated conductive terminal 12. This expanded air is released to the outside through the air vent notch 26. Therefore, the pre-solder 24 that has melted in the recess 22 of the conductive terminal 12 is moved to the outside from between the inner wall of the recess 22 of the conductive terminal 12 and the side surface of the main body 10 that is fitted by the expanded air. Since it is not pushed out, the melted preliminary solder 24 remains in the recess 22 of the conductive terminal 12 in a molten state. Therefore, the end portions of the conductive terminal 12 and the fusible body 14 are reliably soldered by the preliminary solder 24 as shown in FIG. The notch depth of the air vent notch 26 is such that the air vent notch 26 is recessed in the conductive terminal 12 so that the through hole 18 is sealed when the press fitting of the conductive terminal 12 is completed as shown in FIG. It is designed to be covered by the inner wall of 22.

In the above embodiment, a pair of air vent notches 26 are provided in the main body 10 in order to facilitate the assembly work by making the order of press-fitting the pair of conductive terminals 12 into the main body 10 unequal. One is provided on each end face 16 side of each, but the air vent notch 26 is provided only on one end face 16 side, and the conductive terminal 12 is first press-fitted to the end face 16 where the air vent notch is not provided. Then, the conductive terminal 12 may be press-fitted into the end surface 16 on which the air vent notch is provided. Further, a plurality of air vent notches may be provided on one end face 16 or both end faces 16.

Since the chip fuse for mounting on the printed circuit board shown in FIG. 1 has a small size, the ceramic body 10 is manufactured by the steps of powder molding, compression and sintering. In this manufacturing process, the air vent notch 26 has a structure in which the end surface 16 of the main body 10 is notched in order to facilitate manufacturing. However, the point is that when the conductive terminal 12 to be press-fitted later is press-fitted from the end surface 16 of the main body 10 while being heated, it is a ventilation path through which the thermally expanded air in the through hole 18 escapes to the outside. It suffices to have a structure in which the outlet of the ventilation passage is covered by the side wall of the recess 22 of the conductive terminal 12 when the press-fitting is completed. Therefore, instead of the air vent notch 26 as shown in FIGS. 2 to 4, an opening communicating with the side surface near the end face 16 to the through hole 18 may be used. Further, such a ventilation path may be provided near the end surface 16 at a position on a side surface that does not overlap the fusible body passage groove 20.

Further, the shape of the main body of the chip fuse described with reference to FIG. 1 as a preferred embodiment of the present invention is a prismatic body, but the present invention is not limited to this, and any shape such as a cylindrical body may be used. It may be a columnar body. Further, the outer shape of the conductive terminal is not limited to the rectangular shape as shown in FIG. 1, and may be circular, as long as the recess of the conductive terminal fits in the main body without any gap. ..

FIG. 5 is a component diagram of another embodiment of the chip fuse of the present invention having a structure in which the fusible body through groove extends to the other end surface. The chip fuse shown in FIG. 5 differs from the embodiment of FIG. 3 in that the fusible body through groove extends to the other end face in order to facilitate the manufacture of the small ceramic body 10. Other points are the same.

[0016]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects. That is, since the air vent opening that communicates with the through hole is formed on the side surface near the end surface of the main body, when the heated conductive terminal is fitted from the end surface, the air that has been heated and expanded in the through hole is discharged from the opening. Since it can be discharged, the preliminary solder for electrically connecting the concave portion of the conductive terminal and the fusible body is not pushed out by the air that has expanded from the inner surface of the concave portion of the conductive terminal to the outer peripheral surface of the main body. Therefore, the electric connection between the conductive terminal and the fusible material is surely made, and the yield is improved and the reliability of the chip fuse is increased.

[Brief description of drawings]

FIG. 1 is a perspective view of a finished chip fuse of the present invention.

FIG. 2 is a perspective view of the main body 10 shown in FIG.

FIG. 3 is a component configuration diagram of the chip fuse shown in FIG. 1 before assembling.

4 is a cross-sectional view of the chip fuse after the components of the chip fuse shown in FIG. 3 have been assembled, viewed from a surface including a fusible body 14, a fusible body passing groove 20 and an air vent notch 26. FIG.

FIG. 5 is a structural view of components of another embodiment of the chip fuse of the present invention having a structure in which a fusible body through groove extends to the other end surface.

FIG. 6 is a component configuration diagram of a conventional chip fuse.

[Explanation of symbols]

10: body, 12: conductive terminal, 14: fusible body, 16:
End surface, 18: through hole, 20: fusible material through groove, 22: concave portion, 24: preliminary solder, 2
6: Air vent notch

Claims (4)

[Scope of utility model registration request] 1. A main body made of a heat-resistant insulating material and having a shape of a columnar body, the through-hole penetrating between both end faces in the longitudinal direction, and the penetrating hole on the outer peripheral surface of at least one end face of the both end faces. A body having an opening communicating with the hole, and a fusible body stretched over the through hole, each end of which extends along the both end surfaces and the outer peripheral surface in contact therewith. The fusible body is stopped, and the recesses are fitted to the outer peripheral surfaces of the both end surfaces, and when fitted, the recess and the end of the fusible body are electrically connected via preliminary solder. And a pair of conductive terminal portions in which the recess covers the opening of the main body. 2. The chip fuse according to claim 1, wherein the opening of the main body is a notch formed in the end surface. 3. The chip fuse according to claim 1, wherein the opening is formed on the outer peripheral surface of the both end surfaces. 4. The chip fuse according to claim 1, wherein a fusible body through groove is formed on outer peripheral surfaces of both end surfaces of the main body, and the end of the fusible body is locked in the fusible body through groove. A chip fuse in which an opening is arranged at a position different from that of the fusible body through groove.