JPH11297545A - Power feeding choke coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to save the space by using two drum chokes each composed of coils mounted between flanges of a drum type core, making parallel the coil winding axial directions of the drum chokes, and making the flange side faces of both ends of each core bonded or placed to each other. SOLUTION: A drum choke 5 having a coil 4 wound around a coil winding part of a drum type core composed of the coil winding part and flanges 2, 3 at both ends thereof and drum choke 10 in the same specification as the drum choke 5 form a choke coil with the their respective flanges 2, 7 and 3 bonded at the side faces. The coil winding part has a round shape such as circular or elliptic to avoid breaking wires at the edges etc., to improve the workability, the flanges at the core both ends have a larger shape than the coil outer diameter to prevent the coil damage or wire breaking. The used two drum cokes are wound in the same direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a choke coil for preventing an AC component of a station power supply circuit mounted on a communication device or the like.

[0002]

2. Description of the Related Art FIG. 7 is a schematic diagram of a station power supply circuit. The DC biased signal 51 is input, and the power supply
2 is a circuit that supplies a direct current and supplies only an AC component to the signal processing unit 53. Before the power supply unit 52, the choke coils 54 and 55 block the AC component, and the signal processing unit 53 DC is blocked by the capacitor 56 and the transformer 57. Note that the power supply section 52 is intended to supply drive voltages to various elements of the signal processing section 53.

A choke coil 54 in front of a power supply section 52,
By inserting 55 for each circuit line, a necessary inductance can always be generated with respect to the AC component in the common mode (between the line and the earth) and the normal mode (between the line and the line). Could be stopped. The shape of the magnetic core used for the choke coils 54 and 55 is generally EE type or EI type, and a gap is provided in a part of the magnetic path to provide DC superimposition characteristics.

[0004]

Heretofore, the above-mentioned choke coils have been used as a set of two pieces, always requiring two choke coil spaces, and space saving has been an important issue. In addition, there is a method in which a single choke coil is wound around a common magnetic core to form a choke coil corresponding to both lines. In this method, only one of the common mode and the normal mode is used. It could not respond, and the AC component rejection was insufficient.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a choke coil in a power supply circuit which saves space and provides a choke coil compatible with a common mode and a normal mode.

[0006]

According to the present invention, there is provided a power supply choke coil comprising a magnetic core made of a magnetic material and a coil wound around the magnetic core, wherein the magnetic core is an open magnetic path drum type magnetic core, A power supply choke coil in which two drum chokes each formed by winding a coil between magnetic core flanges are used, and the coil winding axes of the drum chokes are parallel, and the flange side surfaces at both ends of each magnetic core are joined or approached. .

The present invention also provides a power supply choke coil comprising a magnetic core made of a magnetic material and a coil wound around the magnetic core, wherein the magnetic core has a substantially cylindrical coil winding portion, and the coil winding portion is provided at both ends. An open magnetic circuit core having a plate-shaped portion larger than the magnetic core cross-sectional area of the winding portion, using two choke coils each formed by winding a coil around a substantially cylindrical coil winding portion;
A power supply choke coil in which the side surfaces of the flat plate portions at both ends of each magnetic core are joined or arranged close to each other with the coil winding axis parallel.

The two choke coils used in the present invention are power supply choke coils in which the polarities are set in the same direction and the side surfaces of the flange portions at both ends of the magnetic core are joined or approached.

Further, according to the present invention, a choke coil comprising a magnetic core comprising a substantially cylindrical coil winding portion, flange portions at both ends thereof, and a coil wound around the coil winding portion, is provided with a coil winding axis parallel to the coil winding axis. When the two choke coils are arranged as described above, by making the side surfaces of the respective flange portions face each other, a unique magnetic path is formed for each magnetic core in the common mode, and a common magnetic path is formed in the normal mode. It is a choke coil.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a choke coil of the present invention,
A drum choke 5 in which a coil 4 is wound around a coil winding portion of a drum type magnetic core including a coil winding portion and flange portions 2 and 3 at both ends thereof, and a drum type choke 10 having the same specifications as the drum choke 5, A choke coil is formed by joining and arranging the side surfaces of the respective flanges 2, 7, 3, and 8.

The operation of the choke coil of FIG. 1 in each mode is shown in FIGS. FIG. 2 is a diagram showing the operation in the common mode. In each of the drum cores, magnetic fluxes 11 and 13 in the same direction are generated by the coils 4 and 9. The magnetic flux tries to flow to the one with high conductivity,
The magnetic flux 11 indicates the direction to the other magnetic core near the joint 15 of the flange 3, but the magnetic flux 11 also indicates the direction of the joint 1 of the flange 8 at the other magnetic core.
Since a magnetic flux opposing the magnetic flux 11 is generated around 5,
For the magnetic flux 11, the other magnetic core has a lower conductivity than the atmosphere, so that the magnetic flux 11 occupies at least half of the magnetic path 1 occupied by the atmosphere.
Form 2 Similarly, the magnetic flux 13 forms a magnetic path 14 in the other magnetic core. As a result, each of the drum chokes 5 and 10 has substantially the same inductance as that of the drum choke alone, and the distance between AB Is 1/2 the value of the drum choke when used alone.

FIG. 3 is a diagram showing the operation in the normal mode.
As a result, magnetic fluxes 11 and 13 are generated in opposite directions, and the directions of the magnetic fluxes generated in the flanges near the respective magnetic core joints 15 become the same, and the respective magnetic fluxes 11 and 14 share a common magnetic path 16 extending over the adjacent magnetic cores. To form In addition, since the gap length between the magnetic path 16 and the inductance between C and D at this time was small, the inductance could be larger than that of the drum choke when used alone.

In the normal mode, it is necessary to always generate an inductance with respect to a direct current.
There are two ways to obtain a high inductance value by joining the flanges of adjacent magnetic cores like the drum type magnetic core shown in Fig. 1, and to improve the DC current resistance by providing an arbitrary gap between the flange side surfaces.

[0014]

FIG. 4 shows a first embodiment of the choke coil of the present invention. The choke coil of the present invention was housed in a case 17 made of a heat-resistant resin provided with a plurality of surface mounting terminals 18 and a plurality of lead connection terminals 19 which are extensions of the terminals. The drum chokes 5 and 10 have a drum-type magnetic core having a Ni-based ferrite material NB65S (manufactured by Hitachi Metals) having a coil winding part core diameter of 2.6 mmφ, a flange diameter at both ends of 5 mmφ, and a total length of 9 m.
m, the coil was 320 turns with a wire diameter of 0.1 mmφ, and the coil winding direction was the same direction.

Table 1 shows the inductance characteristics in each mode with the choke coil of the first embodiment shown in FIG. 4 at a measurement frequency of 10 KHz. The flange portions at both ends of the magnetic cores of the adjacent drum chokes 5 and 10 are shown. This is a measured value when the side facing distances of 2, 7, 3 and 8 are 0 mm (joining) and a gap of 75 μm is provided.

[0016]

[Table 1]

In the choke coil according to the first embodiment of the present invention, it is possible to obtain about 13 times the inductance in the normal mode at the distance of opposing flange side surfaces of 0 mm and about 5 times the inductance in the gap of 75 μm in the normal mode as compared with the inductance of the drum choke alone. did it. The common mode showed a stable inductance irrespective of the distance between the flange side surfaces.

FIG. 5 shows a normal mode DC superimposition characteristic when the distance between the side faces of the flange portion is 0 mm. The inductance has a characteristic that decreases substantially linearly with respect to the DC superimposed current, and this characteristic is due to the fact that the collar shape of the magnetic core is circular.

In the choke coil of the first embodiment, the coil can be wound directly around the magnetic core using Ni-based ferrite having a low conductivity, and an insulator such as a bobbin is not required.
The outer shape of the choke coil of Example 1 of the present invention enclosed in the case shown in FIG.
mm choke coil.

In the second embodiment, a magnetic permeability material of Mn-based ferrite was used as the magnetic core material. As the ferrite material, MD70D (manufactured by Hitachi Metals) having an initial permeability of 7000 is used, and the magnetic core has a cylindrical shape with the coil winding portion 20 shown in FIG. Using the magnetic core composed of the flat plate portion 21 having a cross-sectional area, the coils 23 were wound respectively, and the same inductance measurement as in Example 1 was performed. (The coil 23 in FIG. 6 is abbreviated as a broken line)

[0021]

[Table 2]

In the second embodiment, the inductance in the normal mode is 100 times or more larger than the inductance of a single unit. However, the influence of the side facing distance of the flat plate portions 21 at both ends of the magnetic core is large, and the inductance is 75 μm. To 1/8. This is because the side surface 22 facing the flat plate portion of the magnetic core other than the flat plate portion 21 of the magnetic core is flat.

That is, in the choke coil of the present invention, the opposing surfaces of the flange portions at both ends of the magnetic core are made smaller as the linear surfaces of the first embodiment, so that the variation is suppressed even if they are incompletely joined. By providing a gap between the side surfaces of the flange in advance, a choke coil having improved DC superimposition characteristics in the normal mode can be obtained.

In addition, it is necessary to insulate the coil and the magnetic core by using the Mn-based ferrite having a low conductivity of the embodiment 2 as the magnetic core, but the magnetic permeability is higher than that of the Ni-based ferrite, and the magnetic core is small. And the effect of reducing the number of coil turns is obtained.

The shape of the magnetic core is such that the coil winding portion is circular,
The rounded shape such as an ellipse prevents breakage due to edges, etc., and improves workability. Since it does not come into contact with, the coil flaw and disconnection can be prevented beforehand.

The use of Ni-based ferrite as the magnetic core material does not require components such as a coil bobbin, so that the number of components is reduced, the assembling work can be reduced, and the labor for component management can be reduced.

In the choke coil of the present invention, the winding directions of the two drum chokes used are described as being the same. However, when the winding directions of the drum chokes are combined in the opposite direction, the characteristics opposite to those of the present invention are obtained. And high inductance is obtained in common mode,
In the normal mode, the inductance becomes low.
Since the low inductance in the normal mode becomes further lower due to the DC superimposition characteristic, it is not suitable as a power supply choke coil, and the present invention capable of generating a high inductance even when DC is superimposed is most preferable.

[0028]

According to the choke coil of the present invention, by combining two choke coils using the open magnetic core, it is possible to prevent the AC component of the common mode and the normal mode, and the high inductance is provided in the normal mode. And improved DC current resistance. Further, the space for two choke coils required for the power supply circuit can be reduced by half, and significant effects such as downsizing of the station power supply circuit, reduction in the number of parts, and cost reduction can be obtained. In addition, as a choke coil, winding work is easy, and low-conductivity Ni is used for the core material.
The use of system ferrite eliminates the need for various insulators, reducing the number of parts and reducing the number of work steps.
An inexpensive choke coil corresponding to the common mode and the normal mode can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a choke coil according to the present invention.

FIG. 2 shows the operation of the choke coil of the present invention in a common mode.

FIG. 3 shows the operation of the choke coil of the present invention in a normal mode.

FIG. 4 is a first embodiment of a choke coil according to the present invention.

FIG. 5 is a diagram of a DC superposition characteristic of the first embodiment.

FIG. 6 shows a second embodiment of the choke coil of the present invention.

FIG. 7 is a diagram of a station power supply circuit.

[Explanation of symbols]

 2, 3, 7, 8 Flange 4, 9 Coil 5, 10 Drum choke

Claims (4)

[Claims] 1. A power supply choke coil comprising a magnetic core made of a magnetic material and a coil wound around the magnetic core, wherein the magnetic core is a drum-shaped magnetic core having an open magnetic path, and the coil is wound between flanges of the drum-shaped magnetic core. A choke coil for power supply, characterized in that two drum chokes are used, the coil winding axes of the drum chokes are parallel to each other, and the flange side surfaces at both ends of the respective magnetic cores are joined or close to each other. 2. A power supply choke coil comprising a magnetic core made of a magnetic material and a coil wound on the magnetic core, wherein the magnetic core has a substantially cylindrical coil winding portion, and the coil winding portion is provided at both ends thereof. An open-magnetic-path magnetic core having a plate-shaped portion having a larger cross-sectional area than a magnetic core, and two choke coils each formed by winding a coil around a substantially cylindrical coil winding portion are used. A choke coil for power supply, characterized in that the flat plate side surfaces at both ends of the magnetic core are joined or arranged close to each other. 3. The power supply choke coil according to claim 1, wherein the two choke coils have the same polarity and are combined. 4. A choke coil comprising a substantially cylindrical coil winding portion, a magnetic core comprising flange portions at both ends thereof, and a coil wound around said coil winding portion, wherein said choke coil is wound parallel to a coil winding axis. When two coils are arranged, the side faces of the respective flange portions are opposed to each other, so that a unique magnetic path is formed for each magnetic core in the common mode, and a common magnetic path is formed in the normal mode. Power supply choke coil.