JPH07106152A - Annular core and method of insulating the core - Google Patents

Abstract

PURPOSE:To provide a handy annular core with stable quality and a method of insulating the core by forming an insulating cover on an annular core surface integrally with injection molding although for use in the insulating cover of the annular core used for a common mode chalk coil a body comprising a resin molded article and a cover are conventionally combined with each other. CONSTITUTION:In an insulating cover including a central partition plate 9 for insulating windings from each other and a partition table 10 there are provided an annular core and a method of insulating the core wherein the annular core is buried and molded in electrically insulating resin after positioning the annular core in a metal mold with pins at a location along the partition table 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating method for an annular core used in a common mode choke coil for preventing electromagnetic noise in an electronic device.

[0002]

2. Description of the Related Art A conventional annular core insulation method in which two windings are separately wound around one annular core when forming a common mode choke coil is as shown in FIG. In this method, the annular core 3, which is usually a toroidal type core or a frame type core, is housed in an insulating cover made of an insulating resin which is divided into a cover plate 2 and a cover plate 2. The main body 1 is provided with an annular bottom between the double cylinders to form a core storage space, and has a required length from both end surfaces of the inner cylinder for equally dividing the inner cylinder space into two parts parallel to the axial direction. Providing a protruding central partition plate 4 integrally with the inner cylinder,
Further, it has a structure in which the protruding portion of the central partition plate 4 is connected to a pair of lower partition plates 5 that are wider than the central partition plate 4 that is integrally provided on the annular bottom in the radial direction and have the same height as the protruding portions. The cover plate 2 is an annular plate that fits into the opening of the double cylinder of the main body 1, and has a pair of upper partition plates 6 corresponding to the lower partition plate 5 of the main body 1 on the surface thereof.
It is a structure that is integrally provided. The insulating cover insulates the two windings wound through the divided space of the inner cylinder from the annular core 3, and the central partition 4, the lower partition plate 5, and the upper partition 6 insulate the windings from each other.

[0003]

In the case of an insulating cover divided into a main body and a cover plate, a gap is formed between the substrate and the main body, which is an extra space for accommodating the annular core.
In order to secure a required insulation distance between the winding wire and the annular core, it is necessary to increase the thickness of the substrate and the depth of the main body. Further, while the insulating cover can be manufactured with a small dimensional tolerance, it is difficult to accurately and inexpensively manufacture the annular core, and the dimensional tolerance is large. Therefore, the annular core may rattle in the insulating cover, and the insulating cover may be distorted by the winding. The present invention is to obtain a resin-molded annular core integrally formed with a resin used for a common mode choke coil, and an insulating method thereof.

[0004]

The present invention focuses on the fact that the insulating cover of the annular core used for the common mode choke coil is provided with the central partition plate and partition for insulating the windings from each other. This is done by supporting the annular core by abutting the tips of two or more pins on the outer peripheral surface corresponding to the partition of the annular core, and embedding the annular core in the resin by injection molding to form the annular core surface. An annular core in which an insulating cover is directly formed on the core and a manufacturing method thereof are characterized.

[0005]

The pin supports the annular core at a place where the trace of the pin does not impair the required insulation distance between the winding and the annular core, and ensures the insulation characteristics by making the thickness of the insulating cover uniform with respect to the annular core.

[0006]

1 is an external perspective view of an embodiment of an insulating cover showing an insulating method for an annular core for a common mode choke coil according to the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. The insulating cover 7 is provided at a position opposite to the inner wall of the injection molding die (not shown) of the annular core 3 so as to be retractable in order to position the annular core in the injection molding die. The pin is made by positioning the annular core with a pin, supporting the annular core in the mold in a suspended state, and embedding the annular core 3 with resin by injection molding. 1 and 2, the small hole 8 on the outer peripheral surface of the insulating cover 7 is
It is a trace of removing the pin. Therefore, the surface of the annular core 3 is closely covered with the insulating cover 7 except for the small holes 8. The small hole 8 is formed integrally with the insulating cover 7, and has a central partition plate 9 on the inner peripheral portion and partition plates 10 on the upper and lower surfaces.
It is in the place corresponding to. The two windings (not shown) of the choke coil are arranged on the insulating cover 7 from the center partition plate 9
It is wound through the spaces on both sides of each of the above, and is not wound around the outer peripheral surface indicated by the arrow in FIG. Since the small hole 8 is located in the center of the portion where the winding does not exist, the insulation distance between the annular core 3 and the winding can be ensured to be equal to or larger than a predetermined dimension. Because of the small holes 8, it is not necessary to increase the wall thickness of the outer peripheral portion, and the wall thickness can be reduced to the minimum moldable thickness. The annular core of this embodiment may be a soft magnetic ferrite core or an annular core made of a wound magnetic core made of an amorphous material.

[0007]

According to the method of insulating a ring-shaped core according to the present invention, the insulating cover can be made compact and the required amount of resin can be reduced. Since the annular core does not rattle in the insulating cover, abnormal noise does not occur during use, and the winding does not distort the insulating cover, so the coil finish is uniform and good, It has the effect of stabilizing the quality. Further, since the annular core wrapped with the insulating cover is easy to handle, it has the effect of improving the efficiency of the winding work.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a vertical cross-sectional view showing an example of a conventional annular core insulating method in a state where the annular core is housed in an insulating cover.

[Explanation of symbols]

 1 Main body 2 Lid plate 3 Annular core 4,9 Central partition plate 5 Lower partition plate 6 Upper partition plate 7 Insulation cover 8 Small hole 10 Partition stand

Claims (2)

[Claims] 1. An insulating cover made of resin having electric insulation properties, which is provided with a central partition plate for insulating the windings from each other and a partition stand extending from the central partition plate, and is uniformly and integrally covered with the insulating cover. Annular core. 2. A resin having electrical insulation characteristics, wherein an insulating cover having a central partition plate and a partition for insulating the windings from each other is positioned in the molding die at a position along the partition so that the annular core is positioned by a pin. An insulating method for an annular core, which is characterized by being embedded and molded in the inside.