JP2000208343A - Common mode choke coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a common mode choke coil wherein a filter characteristics can be set at will. SOLUTION: Two or more kinds of toroidal core materials are housed and bonded inside three hollow case bodies 4a, 5a, and 6a to form core units 4, 5, and 6. These are stacked to form a composite core 3, with a conductive wire wound to form a common mode choke coil. In short, a conductive wire is wound around the composite core formed by stacking a plurality of core units, wherein a core material is housed in a case body while a magnetic material of core material is different for at least one of the plurality of core units, so that setting the combination of core materials with different characteristics at will allows free setting for filter characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a common mode choke coil used as a noise filter for cutting off or reducing noise passing through a power supply line or the like, and more particularly to a common mode choke whose filter characteristics can be freely set. It relates to coils.

[0002]

2. Description of the Related Art Conventionally, a noise filter composed of a coil and a capacitor is often used in order to cut off and reduce various kinds of noise passing through a power supply line or the like. As a coil of the noise filter, a common mode choke coil is used. As a type of the coil, there are an E-shaped core, a U-shaped core, a toroidal core, and the like when classified according to a shape of a core (magnetic core), and the types are classified according to a material of the core. And a ferrite magnetic material, a nano (ultrafine) crystalline soft magnetic material, an amorphous magnetic material, and the like.

Among the features of the common mode choke coil due to the difference in core material, the advantages of a ferrite core are generally strong against magnetic saturation, low in cost, and large in inductance at a signal of several hundred KHz. The characteristic is that the inductance for signals other than several hundred KHz is small, and particularly the inductance between 1 KHz and about 100 KHz is quite small.

On the other hand, a nano (ultrafine) crystalline soft magnetic material has an ultrafine and uniform grain structure of about 10 nm in grain size.
It is formed by winding a ribbon made of a base alloy, and has high saturation magnetic flux density, high magnetic permeability, and low magnetic core loss characteristics. As a feature, although it has the advantage of high inductance (about 20 times that of ferrite at 1 KHz) due to its high magnetic permeability, it is more easily magnetically saturated than a ferrite core (particularly, it increases when the number of coil turns increases. Some disadvantages are that the cost is three to four times higher than that of the ferrite core, and that the pulse attenuation characteristics when a load current is applied are considerably worse than the ferrite core.

[0005]

As described above, although the filter characteristics greatly differ depending on the core material, when designing and manufacturing a common mode choke coil,
There is no way to select the core material first and then set the other factors, so that the filter characteristics can be set freely, for example, between the ferrite magnetic material and the nano (ultrafine) crystalline soft magnetic material. Even if filter characteristics are desired, it is extremely difficult to realize them.

Accordingly, an object of the present invention is to provide a common mode choke coil capable of freely setting filter characteristics.

[0007]

In order to achieve the above object, a common mode choke coil according to the present invention is configured such that a conductive wire is connected to a composite core formed by stacking a plurality of core units each containing a core material in a case body. While being wound, at least one of the plurality of core units has a different core magnetic material.

The present invention is characterized in that a ferrite magnetic material and a nanocrystalline soft magnetic material are used as the core material.

[0009] Further, the case body at the upper and lower ends when the core units are stacked is characterized by protruding insulating ribs for separating adjacent conductors of different phases.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present embodiment will be described below by taking a toroidal three-phase common mode choke coil as an example. FIG. 1 shows a common mode choke coil 1 of the present invention, in which a conductive wire 2 is formed by dividing a toroidal composite core 3 into three and spirally winding the same.

FIG. 2 shows a composite core 3 before the conductor 2 is wound.
FIG. 3 is an exploded view of the composite core 3. The composite core 3 has core units 4, 5, 6 formed by housing and bonding toroidal core materials (not shown) to be described later in three hollow case bodies 4a, 5a, 6a, respectively.
The core unit 4,
Separators 7 separating the conductors 2 of three circuits are provided on the inner circumference of 5 and 6.
Are engaged.

The case bodies 4a and 6a of the core units 4 and 6 located at the upper and lower ends of the composite core 3 are vertically symmetrical, and different from the shape of the case body 5a of the core unit 5 located at the center, protrude in the vertical direction. Ribs 8 are formed to prevent the conductors 2 of the three circuits from getting too close.

The case members 4a, 5a and 6a are made of an insulating material such as a synthetic resin material which is vertically divided into two parts, and as long as the toroidal core material (not shown) to be accommodated therein conforms to the shape. Any magnetic material such as a ferrite magnetic material (integrated or laminated), a nano (ultrafine) crystalline soft magnetic material (a thin ribbon wound), and an amorphous magnetic material can be applied.

The results of characteristic evaluation of the common mode choke coil 1 of the present invention having the above-described configuration are shown below. The core unit used for this characteristic evaluation is a core unit formed by laminating two ferrite magnetic materials having a diameter of 117 mm, and two nano (ultrafine) crystalline soft magnetic materials (Finemet: registered trademark) having a diameter of 118 mm. The core unit is formed by laminating two core units in any combination and the number of turns of the conductor is five turns. That is, two core units of ferrite magnetic material, two core units of nano (ultrafine) crystalline soft magnetic material, one core unit of ferrite magnetic material and one core unit of nano (ultrafine) crystalline soft magnetic material
The characteristics of the three combinations were evaluated as follows.

FIG. 4 shows the frequency characteristics of the inductance of the three common mode choke coils described above. In the case of a core made of only a ferrite magnetic material, the inductance has a low value independent of the frequency.
1 KHz or more for a core made of only nano (ultrafine) crystalline soft magnetic material
Ferrite magnetic material and nano (ultra-fine) while inductance at about 100 KHz is large and extremes
The composite core combining the crystalline soft magnetic material shows a much larger inductance between 1 KHz and about 100 KHz, though not as large as the nano (ultra-fine) crystalline soft magnetic material, as compared to the core made of ferrite magnetic material alone.

FIG. 5 shows a saturation proof characteristic (1K) represented by inductance with respect to the number of turns in the DC superposition test (1A) in the three common mode choke coils described above.
Hz), the core having only a ferrite magnetic material has a positive characteristic in which the inductance increases as the number of turns increases, and the core having only a nano (ultrafine) crystalline soft magnetic material has a small inductance when the number of turns exceeds three. On the other hand, a composite core combining a ferrite magnetic material and a nano (ultra-fine) crystalline soft magnetic material shows a moderate positive characteristic between the ferrite magnetic material and the nano (ultrafine) crystalline soft magnetic material.

FIG. 6 shows pulse decay characteristics (at 0.9 A DC superimposition) represented by an output voltage with respect to an input voltage. A composite core combining a ferrite magnetic material and a nano (ultra-fine) crystalline soft magnetic material has a ferrite magnetic material. It can be seen that the material has characteristics between the core composed of only the material and the core composed of only the nano (ultra-fine) crystalline soft magnetic material.

According to the above-described characteristic evaluation, the common mode choke coil of the present invention using a composite core in which a ferrite magnetic material and a nano (ultra-fine) crystalline soft magnetic material are combined is compared with a ferrite magnetic material alone. As a result, about 15 times the inductance is obtained (FIG. 4), and the magnetic saturation proof strength is increased (FIG. 5). Further, the pulse attenuation characteristic is superior to that of the nano (ultra-fine) crystalline soft magnetic material alone (FIG. 6), and the cost can be reduced to about 2/3.

Although it is physically possible to stack and house two or more types of core materials inside one case body, a nano (ultra-fine) crystalline soft magnetic material is formed by winding a ribbon. Since it is fragile and formed, it is not suitable because it may be damaged or distorted if it is superimposed directly on a ferrite magnetic material or the like.

Further, in the above-described embodiment, the shape of the core material has been described as a toroidal shape. Of course, core materials having other shapes may be used. In addition to magnetic materials and nano (ultra-fine) crystalline soft magnetic materials, it is possible to use amorphous magnetic materials, and different types of ferrite magnetic materials with different characteristics even with the same ferrite magnetic material. Since it can be set freely, as a designer of the common mode choke coil, the degree of freedom of design for obtaining desired filter characteristics is greatly increased.

[0021]

As described above in detail, according to the common mode choke coil of the present invention, the conductor is wound on a composite core formed by stacking a plurality of core units each containing a core material in a case body. In addition, at least one of the plurality of core units has a different magnetic material of the core material, so that the filter characteristics can be freely set by freely setting combinations of core materials having different characteristics. .

Further, by using a ferrite magnetic material and a nanocrystalline soft magnetic material as the core material, a large inductance can be obtained as compared with the ferrite magnetic material alone,
The magnetic saturation strength increases. Furthermore, compared with only the nano (ultra-fine) crystalline soft magnetic material, the pulse attenuation characteristics are excellent and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a common mode choke coil according to the present invention.

FIG. 2 is a perspective view showing a composite core of the common mode choke coil of the present invention.

FIG. 3 is an exploded explanatory view showing a composite core of the common mode choke coil of the present invention.

FIG. 4 is a graph comparing characteristics of a common mode choke coil.

FIG. 5 is a graph comparing characteristics of a common mode choke coil.

FIG. 6 is a graph comparing the characteristics of a common mode choke coil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Common mode choke coil 2 Conductor 3 Composite core 4,5,6 Core unit 4a, 5a, 6a Case body 7 Separator 8 Rib

Claims (3)

[Claims] 1. A conductive wire is wound around a composite core formed by stacking a plurality of core units each containing a core material in a case body, and at least one of the plurality of core units is formed of a core material. A common mode choke coil characterized by using different magnetic materials. 2. The common mode choke coil according to claim 1, wherein a ferrite magnetic material and a nanocrystalline soft magnetic material are used as the core material. 3. The common mode choke coil according to claim 1, wherein the upper and lower case bodies at the time of stacking the core units are provided with projecting insulating ribs for separating conductive wires of different phases.