JPH11214225A - Manufacture of inductance core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a reliable inductance core which is easily manufactured. SOLUTION: A drum core wherein, as integral molding, an almost cylindrical coil winding part 12, an almost disc-like flange 13, and a rounded part at upper end lower edges of a coil lead-out groove 14 are formed is manufactured. The coil lead-out groove 14 is formed on a peripheral surface 13a of the flange 13, with its upper and lower edges formed into R-shape so that no coil is flawed. Thus, the coil is hard to be flawed at coil winding, and short-circuiting is avoided from occurring due to breakdown-strength fall even with a large core which requires high inductance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for manufacturing an inductance core.

[0002]

2. Description of the Related Art As a conventional inductance core, a drum core having a circular coil winding portion and a circular flange is known.

Conventionally, drum-type cores have been manufactured by cutting a cylindrical molded product. In recent years, however, in order to greatly reduce the cutting process, integral molding (parts in the case of powder pressure molding) has been carried out. Are integrally formed).

FIG. 3 shows a drum-shaped inductance core 1 manufactured by integral molding. Core 1 shown in FIG.
Is formed by integrally forming a cylindrical coil winding portion 2, a disk-shaped flange 3, and a coil extraction groove 4.

[0005] Since the integral molding is a method of molding by pressing a pair of dies against each other, an unnecessary molding mark is necessarily generated as the core 1 due to the engagement of the dies.
In the case of the core 1 shown in FIG.
a, molding marks are formed on the peripheral surface 3a of the flange 3 and the inner surface 3b of the flange 3, respectively. The molding mark is the winding part 2
The flat surface 5 and the circumferential surface 2a of the flange 3
6 appears on the inner surface 3b of the flange 3 as a twill line 7.

[0006]

As described above, the use of the above-mentioned integral molding can greatly reduce the number of cutting steps. However, since the angle 4a of the drawing groove 4 is 90 °, it is an acute angle. However, there is a problem that the coil is easily damaged by the corner 4a. In particular, in the case of a large core that requires high inductance, a high voltage is applied to the coil,
If the coil is slightly damaged, the withstand voltage is reduced and a short circuit is caused, leading to a reduction in reliability. Also, its corner 4
Even if a is to be rounded by machining, a chip is generated at that time, and the chip is more likely to be damaged by the chip.

Accordingly, the present invention has been made in view of the above circumstances, and has as its object to provide a method of manufacturing an inductance core which is highly reliable and easy to manufacture.

[0008]

In order to achieve the above object, a method of manufacturing a core according to the present invention comprises the steps of: forming a substantially cylindrical coil winding portion by powder pressure molding; and forming a substantially circular plate provided at both ends thereof. And an upper and lower edge formed on the peripheral surface of the flange, and formed with an R-shaped coil extraction groove integrally therewith.

(Operation) According to the method of manufacturing a core having the above-described structure, the upper and lower edges of the coil extraction groove are formed in an R shape at the time of integral molding, so that the terminal of the wound coil is damaged when the terminal of the wound coil is extracted. , The reliability is improved, and cutting and polishing can be omitted, thereby facilitating manufacturing.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view of an inductance core obtained by using a manufacturing method according to an embodiment of the present invention.

The inductance core 10 obtained by the present embodiment shown in FIG. 1 is manufactured by forming a substantially cylindrical coil winding portion 12, a substantially disk-shaped flange 13 and a coil drawing groove 14 by integral molding. Formed by

The peripheral surface 13a of the flange 13 is formed, for example, in an elliptical shape. Further, the peripheral surface 13a is a pair of flat surfaces 16, 16 opposed to each other as a molding mark, as shown in FIG. 2, the inner side than the diameter D ₁₀ of the virtual circle circumscribing the peripheral surface 13a of the flange 13 Formed. Also, preferably the virtual circle diameter D ₁₀ of the (10 mm) flat surface 16, 16 between the distance L ₁₂ 0.95 more for the ratio of high inductance of the relative. In this embodiment, the length L of the flat surface 16
11 (2 mm) to reduce the distance L ₁₂ between the flat surfaces 16
(9.8 mm) relatively longer possible and have as high as 0.98 the ratio of the distance L ₁₂ to the diameter D _10.

The coil extraction groove 14 is formed on the peripheral surface 13a of the flange 13, and the upper and lower edges of the extraction groove 14 are formed in an R shape so that the coil is not damaged.

The circumferential surface 12a of the coil winding portion 12 has
A flat surface (not shown) having a width of only about 1 mm as a molding mark appears, and a twill wire 7 as a molding mark similar to that shown in FIG. 3 also appears on the inner surface 13b of the flange 13; These are removed by processing and finishing so as not to stick. Further, since the width of the flat surface as a molding mark appearing on the peripheral surface 12a of the coil winding portion 12 is only about 1 mm, it can be easily removed.

According to the method of manufacturing the inductance core 10 of the present embodiment having the above-described structure, the following effects can be obtained.

(1) Coil extraction groove 14 by integral molding
The upper and lower edges are formed in an R shape, and thereafter, a flat surface as a molding mark appearing on the peripheral surface 12a of the coil winding portion 12 and a twill line as a molding mark appearing on the inner surface 13b of the flange 13 are removed. Therefore, when the coil terminal wound around the coil winding unit 12 is pulled out, the coil terminal is hardly damaged, and even in the case of a large core requiring a high inductance, the occurrence of a short circuit due to a decrease in withstand voltage can be avoided. Performance can be improved. In addition, since the upper and lower edges of the extraction groove are formed in an R shape by integral molding, there is no need to perform work finishing in a subsequent step, and an effect that manufacturing is facilitated is obtained.

(2) Since the flat surface 16 formed on the peripheral surface 13a of the flange 13 is formed inside the imaginary circle circumscribing the peripheral surface 13a of the flange 13, chucking for coil winding is performed. At this time, the elliptical peripheral surface 13a of the flange 13 can be chucked without the chuck hitting the corner of the flat surface 16, so that the corner of the flat surface 16 is not lost, so that stable chucking can be performed and the coil winding can be performed. The process can be performed smoothly.

(3) Since the distance L ₁₂ (9.8 mm) between the flat surfaces 16, 16 formed on the peripheral surface 13 a of the flange 13 is increased, the winding diameter of the coil (9.8 mm) can be reduced. And higher inductance can be achieved.

(4) It is also possible to adjust the diameter of the coil winding portion 12 when the flat surface as a molding mark that has appeared on the peripheral surface 12a of the coil winding portion 12 is removed by grinding. Thereby, the linearity of the inductance can be improved.

The present invention is not limited to the above embodiment, but can be variously modified.

[0022]

As described above in detail, according to the present invention, when the terminal of the wound coil is pulled out by adopting integral molding and forming the upper and lower edges of the coil drawing groove in an R shape. The end of the coil is hardly damaged, and even in the case of a large core that requires high inductance, the occurrence of a short circuit due to a decrease in withstand voltage can be avoided. Since no process is required, an easily manufactured inductance core can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of an inductance core obtained according to an embodiment of the present invention.

FIG. 2 is a plan view of a flange according to the embodiment.

FIG. 3 is a perspective view of a conventional inductance core.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Inductance core 12 Coil winding part 13 Flange 13a Flange peripheral surface 14 Coil extraction groove

Claims (1)

[Claims] 1. A substantially disk-shaped flange is formed at both ends of a substantially cylindrical coil winding portion by a powder pressure molding, and coil extraction grooves having upper and lower edges formed in an R-shape on the peripheral surface of the flange. A method of manufacturing an inductance core, which is formed integrally.