JP2002093625A - Method of rorming depletion layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of forming a depletion layer, without having to polish a hot-type core or usage of an insulating sheet for reducing a man- hours of manufacturing and obtaining a choke coil with sufficient adhering strength and superior appearance. SOLUTION: In the method, a depletion layer is formed into a closed magnetic circuit of a choke coil, made up of an air-cored coil 3 with a wound insulating wire, and upper and lower pot-type manganese-based ferrite cores 1 having an annular recessed part 6 for storing the air-cored coil 3, and lead wire drawing grooves 7 for drawing terminal lead wire of the air-cored coil 3. The pot-type cores 1, having their surfaces treated in insulation with coating layers 2, are overlapped from the upper and the under, and the depletion layer is formed by the coating layers 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a void layer in a closed magnetic circuit of a choke coil containing an air-core coil while overlapping a pot-type core from above and below. The present invention relates to a method for forming a void layer suitable for a choke coil using a pot type core made of a ferrite core.

[0002]

2. Description of the Related Art In recent years, as an inductance element, for example, a closed magnetic circuit type choke coil in which an air-core coil wound with an insulated wire is housed between upper and lower pot-type cores is often used. Generally, in this type of choke coil, a gap layer (hereinafter referred to as a gap) having a different magnetic permeability from that of the pot-type core material is formed in a part of the closed magnetic circuit to adjust electric characteristics such as an inductance value and a current capacity. Means are adopted. Hereinafter, some adjustment means will be specifically described with reference to FIGS. 2 to 6. Each of the pot-type cores 1 and 1 is made of, for example, an Mn-Zn-based ferrite material, and has a central portion. The cylindrical projection 5 has a rectangular parallelepiped structure in which an annular concave portion 6 for accommodating the air-core coil 3 and a lead wire drawing groove 7, 7 for the air-core coil 3 are formed around the columnar projection 5. , And the opposing surfaces are formed in parallel. As shown in FIG. 2, the gap 10 is formed by overlapping the pot-shaped cores 1 and 1 having the polished portions 8 formed by polishing the end face side of the columnar projections 5. As shown in FIG. 3, the columnar projections 5 and a part of the outer periphery thereof are polished linearly to form potted cores 1 and 1 having polished portions 8, 8A and 8A, and the gaps 10 and 10A are overlapped. To form As shown in FIG. 4, the pot-shaped cores 1, 1 are not polished, and an insulating sheet 9 is disposed between the upper and lower pot-shaped cores 1, 1 to form a gap. As shown in FIG. 5, the pot type cores 1 and 1 are not polished, and an insulating sheet 9 is provided only on the end face side of the columnar projection 5 to form a gap. To form As shown in FIG. 6, the pot-shaped cores 1, 1 are not polished, and an insulating sheet 9 is provided on the entire contact surface of the upper and lower pot-shaped cores 1, 1 to form a gap.

[0003]

The above-mentioned adjusting means has advantages and disadvantages, respectively, and does not affect the appearance of the choke coil. However, in order to polish the end face side of the columnar projection 5, the pot type core 1 is used. You have to grind one by one,
There is a problem in that the number of manufacturing steps increases and the pot type core 1 becomes expensive. In this case, a plurality of pot-shaped cores 1 can be polished at a time because the polishing is performed in a straight line, so that the number of manufacturing steps can be significantly reduced. However, the gaps 10A, 10A formed in the polished portions 8A, 8A remain exposed. Is not preferable in terms of appearance. Although the polishing of the pot-shaped cores 1 and 1 is unnecessary and the processing of the insulating sheet 9 is easy, since the pot-shaped cores 1 and 1 do not directly contact each other,
It is necessary to split the air core coil 3 and the pot type cores 1,1
In addition to the problem of the adhesive strength between them, there is also a problem that the number of manufacturing steps increases and the air-core coil 3 becomes expensive. Polishing of the pot type cores 1 and 1 is not required, and processing of the insulating sheet is easy, but if the gaps 10A and 10A formed in the polished portions 8A and 8A are left unexposed, it is not preferable in terms of appearance and reliability. .
Although the polishing of the pot-shaped cores 1 and 1 is unnecessary, the pot-shaped cores 1 and 1 do not directly contact each other, so that there is a problem in adhesive strength, and there is a problem in that the processing of the insulating sheet 9 is complicated and expensive.

[0004] An object of the present invention is to eliminate the difficulties of these adjusting means, and eliminate the need for polishing a pot-type core or an insulating sheet.
It is an object of the present invention to provide a method for forming a void layer that can obtain a choke coil having a sufficient number of manufacturing steps, a sufficient adhesive strength, and an excellent appearance.

[0005]

According to a first aspect of the present invention, there is provided an air-core coil 3 on which an insulated wire is wound, an annular recess 6 for accommodating the air-core coil 3, and a terminal lead wire of the air-core coil 3. A method for forming an air gap layer in a closed magnetic circuit of a choke coil comprising upper and lower pot-shaped cores 1, 1 made of a manganese-based ferrite material having lead wire drawing grooves 7, 7 for deriving a polyimide resin Coating layer 2,2
A method of forming a void layer, comprising: stacking pot-type cores 1 and 1 whose surfaces have been insulated from above and from below, and forming a void layer by the coating layers 2 and 2. In the method of forming the void layer according to the first aspect, the pot-type cores 1, 1 made of a manganese-based ferrite material having a low resistivity are used.
The pot-type cores 1, 1 having a polyimide resin coating layer 2 formed on the surface thereof and subjected to insulation treatment are overlapped from above and below, and the coating layers 2, 2 are used as void layers. The polishing of the portion and the insulating sheet 9 become unnecessary, and the number of manufacturing steps is reduced. Further, since the pot-type cores 1 and 1 are in direct contact with each other, a sufficient adhesive strength can be obtained, and a method of forming a void layer that can provide a choke coil excellent in appearance can be obtained.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings. Note that the present invention is not limited by this.

First Embodiment FIG. 1 is an explanatory view of a method of forming a void layer according to the present invention. FIG. 1A is a plan view showing the configuration of a pot-type core, and FIG. FIG. 2 is a cross-sectional view of a main part showing a configuration of a choke coil using the pot-shaped core of FIG. In the figure, each of 1, 1 is a pot-shaped core made of a manganese-based ferrite material, and is formed in a rectangular parallelepiped shape having an outer diameter of 11.6 mm in width, 12.5 mm in length, and 2.25 mm in height. A cylindrical projection 5 having a diameter of 4.7 mm is formed at the center of the pot-shaped core 1. An air-core coil 3 formed by edgewise winding a flat rectangular insulated wire around the cylindrical projection 5 is formed. An annular concave portion 6 having a depth of 1.25 mm for accommodating therein is formed. The annular recess 6 is formed at a radius of 2.35 mm to 4.8 mm from the center of the pot type core 1. In addition, an end of a U-shaped terminal (not shown) is inserted into one side of the pot-shaped core 1 and a lead wire lead-out groove for leading out a terminal lead wire of the air-core coil 3.
7, 7 are formed with a depth of 1.0 mm.

Reference numerals 2 and 2 denote a coating layer made of a polyimide-based fluororesin which is a feature of the present invention. The coating layer is formed on the entire surface of the pot type cores 1 and 1 to a thickness of 0.1 mm and subjected to an insulation treatment. The opposing surfaces that are in direct contact with each other when the pot-shaped cores 1 and 1 are overlapped from above and below are configured to have a particularly small tolerance and a uniform thickness by a full-surface coating coating technique. The reason is that the manganese-based ferrite material has a low resistivity, so that the pot type core 1,
This is because 1 itself is not an insulator and cannot be used as a core. Therefore, the coating layers 2 and 2 are provided for insulation treatment, and the pot-shaped cores 1 and 1 are superimposed on each other from above and below, and a gap of 0.2 mm in thickness is uniform over the entire contact surface between the pot-shaped cores 1 and 1. Can be formed.

In the method of forming the void layer according to the present invention, it is not necessary to polish a specific portion of the pot-shaped core and the insulating sheet 9 is not required, so that the number of manufacturing steps can be significantly reduced as compared with the conventional adjusting method. it can. Further, since the pot-shaped cores are in direct contact with each other, a choke coil having sufficient adhesive strength and excellent appearance can be obtained.

[0010]

According to the present invention, it is not necessary to polish a specific portion of the pot-type core for forming a gap, and an insulating sheet is not required, so that the number of manufacturing steps is greatly reduced and sufficient adhesive strength is obtained. And a choke coil excellent in appearance can be provided. The practical effect is large.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a method of forming a void layer according to the present invention, wherein FIG. 1 (a) is a plan view showing the configuration of a pot-type core, and FIG. 1 (b) uses the pot-type core of FIG. FIG. 3 is a sectional view of a main part showing a configuration of a choke coil taken.

FIG. 2 is an explanatory diagram showing an example of a conventional example.

FIG. 3 is an explanatory view showing another example of the conventional example.

FIG. 4 is an explanatory view showing another example of the conventional example.

FIG. 5 is an explanatory view showing another example of the conventional example.

FIG. 6 is an explanatory view showing another example of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pot type core 2 Coating layer 3 Air core coil 5 Cylindrical protrusion 6 Annular concave part 7 Lead wire lead-out groove 8,8A, 8A Polishing part 9 Insulating sheet 10,10A Gap

Claims (1)

[Claims] 1. An air-core coil 3 on which an insulated wire is wound, an annular recess 6 for accommodating the air-core coil 3, and lead wire leading grooves 7, 7 for leading terminal wires of the air-core coil 3. A method of forming an air gap layer in a closed magnetic circuit of a choke coil composed of upper and lower pot type cores 1 and 1 made of a manganese-based ferrite material, wherein the pot is insulated with a coating layer 2 and 2 of a polyimide resin. A method for forming a void layer, comprising: laminating mold cores 1, 1 from above and below; and forming a void layer with the coating layers 2, 2.