JPH0513024U - Transformer core - Google Patents

Abstract

(57) [Abstract] [Purpose] When assembling a transformer core by integrating a pair of ferrite cores with tightening members, prevent cracks in parts other than the tightening groove during molding and firing of each ferrite core. To [Structure] Tightening groove portions 4 (4a, 4b, 4c) and 5 (5a, 5) formed on the circumferential surfaces of the ferrite cores 2, 3
Molding is performed so that the density of the portion where b, 5c) is formed and the density of the other portion are substantially equal. by this,
At the time of molding and firing the ferrite cores 2 and 3, the force is not particularly concentrated on the portions other than the tightening groove portions 4 and 5, so that the generation of cracks at these portions can be prevented.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a transformer core formed by integrating a pair of ferrite cores with a fastening member.

[0002]

[Prior Art]

 As a conventional transformer core, there is known a structure in which a pair of U-shaped ferrite cores are prepared and each ferrite core is integrated by a fastening member to form a closed magnetic circuit.

In assembling the ferrite core having such a structure, a mounting groove for mounting the tightening member is formed in advance on the outer peripheral surface of each ferrite core. The formation of the mounting groove is performed at the same time when each ferrite core is compression-molded into a U-shape by using a raw material powder in a mold. Each ferrite core is obtained by firing after molding.

[0004]

[Problems to be solved by the device]

 By the way, in the conventional transformer core, there is a difference in the density between the mounting groove part formed on each ferrite core and the other part, so cracks easily occur in the part other than the mounting groove part during molding and firing. There is a problem. That is, as shown in FIG. 7, when molding the ferrite cores 2 and 3 between the upper mold 9 and the lower mold 10, the mounting groove A portion is deeply pressed from the top, but other than the A portion. Since the pressure is shallower than that of A in part B, the density does not increase. Since the density of the portion B 2 other than this is smaller than that of the mounting groove portion A, the force is concentrated particularly on the portion other than the mounting groove portion during molding and firing, and cracking is likely to occur.

The present invention has been made to address the above problems, and an object of the present invention is to provide a transformer core in which cracks do not occur in parts other than the mounting grooves during molding and firing of the ferrite core. It is a thing.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention forms a closed magnetic circuit with a pair of U-shaped ferrite cores, and has a groove for mounting a fastening member that integrates the ferrite cores formed on the outer peripheral surface of the ferrite core. In the transformer core, the mounting groove is provided over two sides of the U-shaped ferrite core, each tip communicates with the outside, and the mounting groove forms a positioning step for the tightening member. It is characterized by having.

[0007]

[Action]

 The mounting groove is formed by arranging the mounting groove over two sides of the U-shaped ferrite core, allowing each tip to be inserted to the outside, and having a step for positioning the tightening member. It is possible to reduce the difference in density between the formed portion and other portions. Therefore, during molding and firing of the ferrite core, the force is not concentrated particularly on the portion other than the mounting groove portion. Therefore, it is possible to provide a transformer core in which cracks do not occur in the ferrite core during molding and firing.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

1 to 4 show a first embodiment of a transformer core according to the present invention. FIG. 1 is a front view, FIGS. 2 and 3 are plan views, and FIG. 4 is a sectional view.

The transformer core 1 is assembled by assembling a pair of U-shaped ferrite cores 2 and 3 by a tightening member 6 to form a closed magnetic circuit. FIG. 1 shows the arrangement of the pair of ferrite cores 2 and 3 and the fastening member 6 before they are integrated.

The first ferrite core 2 has legs 2a and 2b, and mounting grooves 4 (4a, 4b and 4c) are formed on the outer peripheral surface of the legs 2a and 2b, extending over two sides. The ferrite core 3 has legs 3a and 3b, and mounting grooves 5 (5a, 5b and 5c) are formed on the outer peripheral surface thereof over two sides. The attachment member 6 has an elongated shape and is made of a spring material. The tip portions 6a and 6b bent at both ends are constantly urged inward in the arrow direction X by a spring force. The mounting member 6 can be fitted in the outer peripheral surfaces 4a, 4b, 4c and 5a, 5b, 5c of the ferrite cores 2, 3 in the arrow direction Z. In order to facilitate the fitting of the mounting member 6 at the time of fitting, a taper portion 7 is formed in the groove 4b on the outer peripheral surface of the ferrite core 2 as shown in FIG. 2, and although not shown, the outer circumference of the ferrite core 3 is similarly formed. A taper portion is also formed in the groove portion 5b of the surface. A step is formed between the mounting groove portions 4a and 4b, 5a and 5b so that the mounting member 6 can be positioned when it is fitted.

As shown in FIG. 3, the leg portions 2a and 3a of the ferrite cores 2 and 3 are formed in a columnar joint surface, and a bobbin (not shown) around which a coil is wound is formed on the joint surface. Can be fitted. The connecting surfaces of the other leg portions 2b and 3b of the ferrite cores 2 and 3 are formed in a square shape as shown in FIG. 3, and the groove portions 4 and 5 are formed in the central portions thereof. .. Further, the sectional shape of each of the ferrite cores 2 and 3 shown in FIG. 1 taken along the line BB is as shown in FIG.

Such a pair of ferrite cores 2 and 3 is formed by compression-molding a U-shaped material in a die using ferrite raw material powder as appropriate, and by firing after molding, each ferrite core 2 and 3 is formed. can get. Here, when forming the ferrite cores 2 and 3, the density of the mounting groove portions 4 (4a, 4b, 4c) and 5 (5a, 5b, 5c) and the other portions should be substantially equal. Mold into This molding method can be performed by providing the mounting grooves 4 and 5 over the two sides of the ferrite cores 2 and 3 as described above, and molding so that the respective tips are inserted to the outside. That is, to explain with reference to FIG. 7, the molding is performed so that the pressing force is applied to the portion B higher than the portion A for the mounting groove. Therefore, by performing firing after molding, it is possible to substantially reduce the difference in density between the mounting groove portions 4 (4a, 4b, 4c) and 5 (5a, 5b, 5c) and other portions. it can.

According to the present embodiment as described above, the portions of the mounting groove portions 4 (4a, 4b, 4c) and 5 (5a, 5b, 5c) of the ferrite cores 2 and 3 and the other portions are Since the difference in the density is made small, the force is not concentrated particularly on the portions other than the mounting groove portions 4 and 5 during the molding and firing of the ferrite cores 2 and 3. Therefore, it is possible to provide a transformer core in which cracks do not occur in portions other than the mounting groove portions 4 and 5.

5 and 6 show a second embodiment of the present invention. FIG. 5 is a front view and FIG. 6 is a plan view. FIG. 5 corresponds to FIG. 1 of the above-described embodiment, and FIG. 6 shows an arrangement corresponding to FIG. 2, and the same parts as those of the first embodiment are designated by the same reference numerals.

In this embodiment, when the taper portions 7a and 7b (not shown) are formed in the groove portions 4a and 5a of the outer peripheral surfaces of the ferrite cores 2 and 3 in order to facilitate the fitting of the mounting member 6, , An example applied to a structure in which the tapered portions 7a and 7b are formed so as to extend from the introduction ports of the groove portions 4a and 5a toward the terminal end portion 8. That is, in such a structure, the densities of the mounting groove portions 4 (4a, 4b, 4c) and 5 (5a, 5b, 5c) and the other portions are made substantially equal. ..

According to the second embodiment as described above, as in the first embodiment, the mounting groove portions 4 (4a, 4b, 4c) and 5 (5a, 5b, 5c) of the ferrite cores 2 and 3 are also provided. Since the density of the part) and the density of the other parts are formed to be almost equal, the same action and effect can be obtained.

In each of the embodiments of the present invention, the shape of each ferrite core, the width and the length of the mounting groove, etc. are shown by way of example, and can be appropriately changed according to the purpose, application, etc. Is.

[0019]

[Effect of the device]

 As described above, according to the present invention, the density of the portions where the mounting grooves of each ferrite core are formed and the portions other than this are made substantially equal, so that it is particularly important when molding and firing the ferrite core. The force is not concentrated on the parts other than the mounting groove, and it is possible to prevent cracks from occurring.

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of a transformer core of the present invention.

FIG. 2 is a plan view showing a mounting groove portion of each ferrite core of the transformer core of the first embodiment.

FIG. 3 is a plan view showing a joint surface of each ferrite core of the transformer core of the first embodiment.

FIG. 4 is a BB of FIG. 1 of the transformer core of the first embodiment.
It is a line sectional view.

FIG. 5 is a front view showing a second embodiment of the present invention.

FIG. 6 is a plan view showing a mounting groove portion of each ferrite core of the transformer core of the second embodiment.

FIG. 7 is a conceptual diagram illustrating a method for molding each ferrite core of a conventional transformer core.

[Explanation of symbols]

1 transformer core 2,3 ferrite core 4 (4a, 4b, 4c), 5 (5a, 5b, 5c) mounting groove 6 tightening member 7 taper

Claims (1)

[Scope of utility model registration request] 1. A transformer core comprising a pair of U-shaped ferrite cores forming a closed magnetic circuit, and a groove for mounting a fastening member for integrating the ferrite cores formed on the outer peripheral surface of the ferrite core. In the transformer, the mounting groove is provided over two sides of the U-shaped ferrite core, each tip is communicated with the outside, and the mounting groove has a step for positioning the tightening member. For core.