JPH09320850A - Fixed coil - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To increase the inductance value of a fixed coil, by having a collar (13a, 13b) on the upper and lower parts,
A drum core (1) in which a coil (14) is wound between both collars.
In the fixed coil in which 3) is arranged, the upper and lower parts of the ferrite core (13) are brought into close contact with the upper and lower flanges (13a, 13b).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed coil structure suitable for obtaining a high inductance value in a fixed coil.

[0002]

2. Description of the Related Art FIGS. 6, 7 and 8 are views showing a conventional fixed coil. 6 is a plan view and FIG. 7 is a sectional view. In these drawings, 1 is a terminal, 2 is a substrate on which the terminal 1 is fixed, and 3
Is a drum core provided with an upper collar 3a and a lower collar 3b, 4 is a coil wound around the drum core 3, and between the lower collars 3a and 3b, and 5 is a ring-shaped ferrite core arranged around the drum core 3. .

[0003]

However, in the fixed coil having the above-mentioned structure, the gaps 6 and 7 are formed between the upper and lower flanges of the drum core 3 and the ferrite core 5, respectively, as shown in FIG. There is a problem that the leakage of the magnetic flux 8 occurs and the inductance value becomes low.

[0004]

The above problems can be solved by closely contacting the upper and lower flanges of the drum core and the upper and lower parts of the ferrite core.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a fixed coil according to the present invention will be described with reference to FIGS. 1, 2 and 3. 1 and 2 are a plan view and a side view, respectively. In these drawings, 11 is a terminal, 12 is a substrate made of an insulating material to which the terminal 11 is fixed, 13 is fixed to the substrate 12, and an upper collar 13a,
A drum core 14 made of a magnetic material provided with a lower collar 13b,
Is a coil wound between the upper flange 13a and the lower flange 13b of the drum core 13, and 15 is a ferrite core disposed around the drum core 13 and fixed to the substrate 12 and made of a magnetic material.

In the fixed coil having the above structure, the upper flange 13a and the lower flange 13b of the drum core 13 and the upper and lower parts of the ferrite core 15 are in close contact with each other. As shown in FIG. There is no leakage of magnetic flux as it flows through 15. This increases the inductance value of the fixed coil.

In FIGS. 1 and 2, reference numeral 16 is an epoxy adhesive, and by using this adhesive 16, the drum core 13 and the ferrite core 15 are more closely attached. Here, when the adhesive 16 is interposed between the drum core 13 and the ferrite core 15 and fixed to each other, a gap is substantially created, and leakage of magnetic flux occurs. As shown in FIG. 2, the adhesive 16 is applied from outside not after the drum core 13 and the ferrite core 15 but after the drum core 13 and the ferrite core 12 are brought into close contact with each other.

FIG. 4 is a diagram showing a second embodiment of the fixed coil according to the present invention. In the figure, portions corresponding to those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 4 is a plan view of an essential part. In the figure, the ferrite core 15 is arranged not in the entire circumference of the drum core 13 but in a part of the half circumference. This is to adjust the inductance value of the fixed coil. In the close contact between the drum core 13 and the ferrite core 15, the first
It is similar to the embodiment.

FIG. 5 is a view showing a third embodiment of the fixed coil according to the present invention. In the figure, portions corresponding to those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 5 is a plan view of an essential part. In the figure, the ferrite cores 15 are arranged not at the entire circumference of the drum core 13 but at three parts of the circumference. This is also for adjusting the inductance value of the fixed coil. The close contact between the drum core 13 and the ferrite core 15 is the same as in the first embodiment.

[0010]

As described above, the fixed coil according to the present invention has the upper and lower flanges, and the ferrite core is arranged around the drum core around which the coil is wound. In the fixed coil, since the upper and lower flanges are closely attached to the upper and lower flanges, respectively,
There are advantages such as an increased inductance value.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of a fixed coil according to the present invention.

FIG. 2 is a side view showing a first embodiment of a fixed coil according to the present invention.

FIG. 3 is a diagram showing the flow of magnetic flux in the first embodiment of the fixed coil according to the present invention.

FIG. 4 is a plan view of a main part showing a second embodiment of the fixed coil according to the present invention.

FIG. 5 is a plan view of a main part showing a third embodiment of the fixed coil according to the present invention.

FIG. 6 is a plan view showing a conventional fixed coil.

FIG. 7 is a cross-sectional view showing a conventional fixed coil.

FIG. 8 is a diagram showing a flow of magnetic flux in a conventional fixed coil.

[Explanation of Codes] 1, 11 Terminals 2, 12 Substrate 3, 13 Drum core 3a, 13a Upper collar 3b, 13b Lower collar 4, 14 Coil 5, 15 Ferrite core 16 Adhesive

Claims (2)

[Claims] 1. A fixed coil having upper and lower flanges, wherein a ferrite core is arranged around a drum core in which a coil is wound between the both flanges, wherein the ferrite core is provided on the upper and lower flanges. A fixed coil characterized in that the upper part and the lower part are closely attached. 2. The fixed coil according to claim 1, wherein an adhesive is applied to the drum core and the ferrite core without interposing an adhesive between the drum core and the ferrite core.