JP2669146B2 - Fuse for semiconductor element protection - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a semiconductor element, and more particularly to a fuse for protecting a semiconductor element used for protecting a large-capacity flat semiconductor element.

[Conventional technology]

FIG. 5 is a vertical sectional view of a conventional fuse 26 for protecting a semiconductor element used for protecting a large-capacity flat semiconductor element having a current capacity of about 1,000 A or more, and FIG. 6 is a front view thereof. Insulator 1
The electrode 2 is provided on one end face of the substrate, and the electrode 3 is provided on the other end face. The electrode 2 is a member having a diameter smaller than the inner diameter of the porcelain bushing 1, and has a convex portion, for example, a rectangular convex portion 2A, provided on the inner surface thereof. The electrode 3 is made of a member having an outer peripheral shape substantially the same as the outer periphery of the porcelain bushing 1, and a convex portion 3A having the same shape as the convex portion 2A of the electrode 2 is provided on the inner surface. The fusible member 4 is joined between the side surface of the projection 2A of the electrode 2 and the side surface of the projection 3A of the electrode plate 3 by a method such as welding. In the figure, the convex portions 2A and 3A are square, and a total of four fusible members are joined to each side surface. The fusible body 4 is often provided with a large number of small holes in order to improve the fusing property.

To assemble such a fuse 26, first, the electrodes 2,
The combined body of 3 and the fusible member 4 is inserted from the other end face of the insulator tube 1 with the electrode 2 first, and the electrode 3 is fixed to the other end face of the insulator tube 1 with screws 12. Next, an arc extinguishing material, for example, arc extinguishing sand 5, is enclosed from the one end surface of the porcelain tube 1 so as to embed the fusible body 4. After that, the cover plate 6 is fixed to the electrode 2 with the screw 13, and the cover plate 6 is further fixed to one end surface of the porcelain tube 1 with the screw 12. Numerals 7 and 8 are packings for preventing leakage of the arc extinguishing 5, and numeral 11 is a display contact mount of the fusing indicator 11A.

FIG. 7 shows the connection between the protective fuse 26 and the flat semiconductor element 21. The flat semiconductor element 21 and the connection conductors 22 and 23 provided on both end surfaces thereof are pressed and contacted by a pressing mechanism composed of a holding plate 24 and a screw 25 to be connected. One connecting conductor 23 is connected to one electrode 2 of the protective fuse 26 with a screw 27 by using a screw hole 2B provided in the central portion of this electrode 2. A connection conductor 29 is formed on the other electrode 3 of the protective fuse 26 by using a screw hole 3B provided at the center of the electrode 3.
Are connected using screws 28.

[Problems to be solved by the invention]

In the above-described protective fuse, the connection conductor 23 between the flat semiconductor element and the protective fuse needs to have a cross-sectional area that allows a current flowing through the flat semiconductor element. The connecting conductors occupy a very large space. This is a serious problem particularly in a large-capacity semiconductor converter using a large number of semiconductor elements. Therefore, as shown in FIG. 8, the electrodes of the flat semiconductor element 21 and the electrodes of the protective fuse are arranged so as to face each other, and are connected by pressure contact by a pressure mechanism composed of a holding plate 24 and a screw 25. However, in this case, the pressing force is required to be 4,000 to 5,000 kg for a flat semiconductor element having a current capacity of about 1,000 A. In the above-mentioned protective fuse, the cover plate 6 or the peripheral portion of the electrode 3 is It will be bent and damaged by the applied pressure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a protective fuse for a semiconductor device that can withstand a large pressing force applied to an electrode.

[Means for solving the problem]

In order to solve the above-mentioned problems, in a fuse for protecting a semiconductor element of the present invention, a porcelain bushing, electrodes provided on both end surfaces of the porcelain bushing, a fusible body joined between these electrodes, and the porcelain bushing And an arc-extinguishing material sealed so as to embed the fusible material in the space formed by the respective electrodes, and one of the electrodes is disposed so as to face one electrode of the semiconductor element. In a fuse for protecting a semiconductor element connected by pressure contact, an electrode has a peripheral portion having an outer peripheral shape substantially the same as the outer peripheral surface of a porcelain tube, and the peripheral portion is formed to be the highest. Also, each electrode has an inner hole at the center,
A fusible body is bonded between the side surfaces of these inner holes.
Furthermore, the outer peripheral shape of the porcelain bushing is square.

[Action]

In the fuse for protecting a semiconductor element according to the present invention, the electrode has substantially the same outer peripheral shape as the outer periphery of the porcelain bushing and is formed so that the peripheral portion becomes highest when fixed to the end face of the porcelain bushing. Pressure is applied to the end face of the insulator tube without applying bending stress to the electrode. Therefore, the electrode portion is not damaged. In addition, these electrodes have an inner hole in the center, and after fixing these electrodes to both end surfaces of the porcelain tube, the fusible body was joined to the side surface of the inner hole from the inside. A fusible body can be joined to the electrode of the present invention having substantially the same outer peripheral shape as that of the embodiment. Furthermore, since the outer peripheral shape of the porcelain insulator is square, it is possible to remove the flesh of the porcelain insulator, excluding the electrode fixing screw portions at the corners, and to reduce the size of the porcelain insulator and the electrode, thus reducing the cost. .

〔Example〕

FIG. 1 is a vertical sectional view of a fuse 30 for protecting a semiconductor element according to an embodiment of the present invention, and FIG. 2 is a front view of the same. An electrode 2 is provided on one end face of the insulator tube 1, and an electrode 3 is provided on the other end face. Each of the electrodes 2 and 3 is made of a member having an outer peripheral shape substantially the same as the outer periphery of the porcelain bushing 1. Inner hole in the center, for example square inner hole 2C or 3C
Is provided. The electrodes 2 and 3 are first fixed to one end surface and the other end surface of the insulator tube 1 by screws 12, and then a fusible member 4 is welded from the inside to the side surfaces of the inner holes of the electrodes 2 and 3 respectively. And the like. In the figure, the inner holes 2C and 3C are quadrangular, and a total of four fusible members are joined to the side surfaces of each inner hole. Next, the cover 3D is fixed to the inner hole 3C of the other electrode 3 with the screw 13, and the inner hole is closed. Next, an arc-extinguishing material, for example, arc-extinguishing sand, is sealed from the inner hole 2C of the electrode 2 so as to embed the fusible body 4, and then the cover 2D is fixed to the inner hole 2C of the electrode 2 with a screw 13.
This inner hole is closed. Reference numerals 7 and 8 denote packings for preventing the extinguishing sand 5 from leaking, and reference numeral 11 denotes a display contact mount for the display 11A. When the electrodes 2 and 3 are fixed to the end face of the insulator tube 1, the structure is such that the periphery of these electrodes is the highest. That is, covers 2C, 2D or screws 12,
13 is the plane 2E and the plane defined by the periphery of the electrode
A recess is provided at the center of the electrode to which these covers or screws are attached so as not to protrude from 3E.

FIG. 3 is a cross-sectional view of the porcelain insulator 1 of the protective fuse 30, showing an example in which the outer peripheral shape of the porcelain insulator is rectangular. By making it square, the electrode fixing screw at the corner is removed,
By removing the extra thickness of the insulator tube, the size of the insulator tube and the electrode can be reduced, and the cost can be reduced.

FIG. 4 shows the connection between the protective fuse 30 and the flat semiconductor element 21. FIG. 4 is the same as FIG. 8, except that the protective fuse 30 of the present invention is used as a protective fuse. That is, one electrode of the flat semiconductor element 21 and one electrode of the protective fuse of the present invention are arranged to face each other, and the connection conductor 22 is arranged to face the other electrode of the flat semiconductor element 21; A connection conductor 29 is arranged to face the other electrode of the protection fuse 30, and these are connected under pressure by a pressure mechanism including a holding plate 24 and a screw 25. In this case, the pressing force is required to be 4,000 to 5,000 kg for a flat semiconductor element having a current capacity of about 1,000 A. This pressing force does not apply bending stress to the electrode 2 or the electrode 3,
Since it is applied to the end surface of the porcelain bushing 1 from the peripheral portion of the electrode, the electrode portion is not damaged. According to the calculation results, the insulator 1 has a pressure resistance of 10 Ton or more, and is sufficiently safe against breakage.

〔The invention's effect〕

In the protective fuse for a semiconductor element of the present invention, the electrode has a peripheral portion having an outer peripheral shape substantially the same as the outer peripheral of the insulator tube,
Since this peripheral part is formed so as to be the highest,
Even if the electrodes of the flat semiconductor element and the electrodes of the protective fuse are arranged opposite to each other and connected by pressure contact, this pressure will be received by the porcelain insulator through the electrodes, withstanding large pressure,
Conventional connection conductors can be eliminated, and the size of the semiconductor conversion device can be significantly reduced. Further, by making the outer peripheral section of the porcelain bushing square, the electrode fixing screw portions at the corners can be removed, and the fleshstone of the porcelain bushing can be removed to reduce the size of the porcelain bushing and the electrodes, thus reducing the cost.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a fuse for protecting a semiconductor element according to an embodiment of the present invention, FIG. 2 is a front view of the same, and FIG.
FIG. 4 is a cross-sectional view of the insulator tube in FIG. 2 and FIG. 4 is a side view of the case where the flat semiconductor element and the protective fuse of the present invention shown in FIG. 1 and FIG. 5 is a longitudinal sectional view of a conventional flat semiconductor device, FIG. 6 is a front view of the same, and FIG. 7 is a case where the flat semiconductor device is connected to the conventional protective fuse shown in FIGS. 5 and 6. Side view of the
FIG. 8 is a side view on the assumption that the flat semiconductor device and the conventional protective fuse shown in FIGS. 5 and 6 are connected by pressure contact. 1: Insulator pipe, 2, 3: Electrode, 2C, 3C: Inner hole, 4: Soluble, 5: Arc extinguishing sand,
21: flat semiconductor element, 24: holding plate, 25: screw, 30: protective fuse in the present invention.

Claims (3)

(57) [Claims] 1. A porcelain insulator, electrodes provided on both end faces of the porcelain insulator, a fusible body joined between the electrodes, and the fusible body in a space formed by the porcelain insulator and the respective electrodes. In a fuse for protection of a semiconductor element, which comprises an arc extinguishing material enclosed so as to be embedded, and one of the electrodes is arranged to face one electrode of the semiconductor element and is connected by pressure contact, the electrode is A fuse for protecting a semiconductor element, which has a peripheral portion having an outer peripheral shape substantially the same as the outer periphery of the porcelain bushing, and is formed so that the peripheral portion has the highest height. 2. The protective fuse for a semiconductor device according to claim 1, wherein each electrode has an inner hole at a central portion, and a fusible material is joined between side surfaces of the inner hole. Fuse for semiconductor device protection. 3. The fuse for protecting a semiconductor element according to claim 1) or 2, wherein the outer peripheral shape of the porcelain insulator is square.