JP2001313216A - Noise current absorber and conductor therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise current absorber which is disposed around an electric wire to absorb noises penetrating into the electric wire from outside and capable of efficiently removing noises in a high-frequency range without increasing a magnetic material in size. SOLUTION: This noise current absorber 2a is composed of a cylindrical ferrite core 6a and a loop-like conductor 8a disposed spreading over the inner and outer surface of the ferrite core 6a. By this setup, the noise current absorber 2a is capable of displaying its frequency characteristics more excellent than usual.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise current absorbing device which is externally fitted to a wire of an electronic device and absorbs a noise current generated inside the electronic device or a noise current generated outside and flowing into the electronic device through the wire. And a conductor used for the noise current absorber.

[0002]

2. Description of the Related Art Conventionally, as a technique for removing or suppressing a noise current (noise) flowing through an electric wire, a noise substance flowing through the electric wire is attenuated by surrounding the electric wire with a magnetic material (for example, ferrite). Known noise current absorbers are known. Such noise current absorbers are of the non-divided type, which is configured to form an annular closed magnetic circuit only with a magnetic material, or form a closed magnetic circuit when the magnetic material divided into multiple parts surrounds an electric wire. There are various types such as split type. When an annular magnetic flux generated by the noise current is generated in the closed magnetic circuit formed by the magnetic material, the electromagnetic energy of the noise current is converted into heat energy inside the magnetic material.

[0003] This characteristic is usually represented by a Z component value (impedance component) with respect to the frequency, and it is said that among the Z components, the R component largely depends on the noise removing effect. To make the R component a large value in the high frequency region,
A method of enlarging the magnetic material is used.

[0004]

However, it is often difficult to increase the size of the magnetic material because electronic devices have been miniaturized in recent years and the space for mounting the magnetic material is often limited.

The present invention has been made in view of the above problems, and has as its object to enable efficient noise removal in a high frequency range without increasing the size.

[0006]

Means for Solving the Problems and Effects of the Invention A noise current absorbing device according to a first aspect of the present invention, which has been made to solve the above problem, comprises a substantially cylindrical magnetic body surrounding an outer peripheral portion of an electric wire; At least one conductor formed in a loop over the inner and outer circumferences of the magnetic body.

According to a second aspect of the present invention, in the noise current absorbing device according to the first aspect, the conductor is configured as a leaf spring for urging the surrounded electric wire vertically in an axial direction. Characterized in that: According to a third aspect of the present invention, in the noise current absorbing device according to the first or second aspect, the magnetic body is divided into two along a surface along an axial direction, and the conductor is The two-divided magnetic body also serves as a holding tool for holding the magnetic body so as not to be detached from a state surrounding the electric wire.

According to a fourth aspect of the present invention, there is provided the noise current absorbing device according to any one of the first to third aspects, further comprising a storage case for storing the magnetic material, wherein the conductor is formed in the storage case. Wherein the magnetic body is stored in the storage case over the inner circumference and the outer circumference of the magnetic body.

According to a fifth aspect of the present invention, there is provided a conductor for a noise current absorber used together with a substantially cylindrical magnetic material surrounding an outer peripheral portion of an electric wire, wherein a loop is formed over the inner and outer peripheries of the magnetic material. It is characterized by being formed in a shape. According to a sixth aspect of the present invention, there is provided the conductor for a noise current absorber according to the fifth aspect, wherein the conductor is configured as a leaf spring for urging the surrounded electric wire vertically in an axial direction. I do.

According to a seventh aspect of the present invention, in the conductor for a noise current absorber according to the fifth aspect, the magnetic body is used together with the magnetic body divided into two along a surface along an axial direction. Is also used as a holder for holding the electric wire in a state where it cannot be detached from the surrounding state.

The present invention according to claim 8 is the conductor for a noise current absorber according to claim 7, wherein the cross section perpendicular to the axis is rectangular and the plane parallel to any side of the rectangle. And a holding piece for holding the magnetic body from a direction perpendicular to the surface.

[0012]

According to the noise current absorbing device of the present invention, a conductor is formed in a substantially cylindrical magnetic body surrounding the outer peripheral portion of a conventional electric wire in a loop shape over the inner and outer peripheries thereof. It was done. This improves the frequency characteristics of the noise current absorber without increasing the size of the magnetic body (described later in Examples). Note that the conductor only needs to be in a loop shape when used. For example, when the noise current absorber is detached from the electric wire, a part thereof is broken, and when the noise current absorber is attached to the electric wire, the cut may be closed to form a loop.

According to a second aspect of the present invention, in the noise current absorbing device, the conductor is configured as a leaf spring for urging the enclosed electric wire vertically in the axial direction. In this case, the relative position between the noise current absorber and the electric wire can be maintained. Claim 3
According to the present invention, the magnetic body is divided into two parts by a surface along the axial direction, and the conductor holds the magnetic body divided into two parts so as not to be detached from the state surrounding the electric wire. Also serves as. In this case, it is not necessary to separately provide a component corresponding to the holder, and the configuration can be simplified.

According to a fourth aspect of the present invention, there is provided a storage case for storing a magnetic material, and the conductor is formed in the storage case. When the magnetic body is stored in the storage case, the conductor is located over the inner and outer circumferences of the magnetic body. According to this noise current absorber, when the magnetic body is covered with the storage case, the magnetic body can be made to have excellent frequency characteristics.

The conductors for noise current absorbers according to the fifth, sixth and seventh aspects (also referred to simply as conductors) are applied to the noise current absorbers according to the first, second and third aspects, respectively. Corresponds to conductor. That is, when these conductors are applied to the corresponding magnetic bodies, excellent frequency characteristics and the above-described effects are exhibited. The conductor for a noise current absorber according to claim 8 is a specific example of the conductor of claim 7. In other words, this conductor has a rectangular cross section perpendicular to the axis, and has a plane parallel to any side of the rectangle.
It is used together with the divided magnetic body, and has a holding piece for holding the magnetic body from a direction perpendicular to the divided surface. Thereby, it can hold | maintain from the state which surrounds an electric wire so that it cannot be detached.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1A is a perspective view showing a state in which a noise current absorber 2a according to an embodiment of the present invention is attached to a cable 4. FIG. The noise current absorber 2a is obtained by attaching a wire-shaped conductor 8a to a cylindrical ferrite core 6 in a loop shape. By the conductor 8a, the inner periphery and the outer periphery of the ferrite core 6 are connected by a conductor. According to such a noise current absorber 2a, the conductor 8
As compared with the conventional noise current absorber having no a, the noise absorption characteristics are excellent.

To confirm this, the following experiment was conducted. As samples, the noise current absorber 2a of the present invention shown in FIG. 1 (b) and the conventional noise current absorber 12 shown in FIG. 1 (c) were connected to an impedance analyzer via a measuring cable 10, respectively. , The frequency characteristic (impedance characteristic) of both impedances is 1 MHz to
Measured over 1800 MHz. As a result, a graph as shown in FIG. 2 was obtained. The horizontal axis is frequency and the vertical axis is impedance. The sample of the present invention is represented by ○, the conventional sample is represented by □, and the hatched portion is the Z component, and the uncoated portion is the R component.

As shown in this graph, both the Z component and the R component show larger values in FIG. 1B, that is, the sample of the present invention. Thereby, according to the noise current absorber 2a, compared with the conventional noise current absorber without the conductor 8a,
About 200 MH without increasing the size of the ferrite core 6
Excellent frequency characteristics can be obtained at frequencies after z.

Embodiments 2 and 3 FIG. 3A shows an example in which the shape of the conductor is changed. In this embodiment, the conductor 8b acts as a leaf spring. As a result, the cable 4 is urged in a direction perpendicular to its axial direction, and the relative position between the noise current absorber 2b and the cable 4 is maintained. And excellent frequency characteristics can be obtained similarly to the noise current absorber 2a.

This embodiment may be configured as shown in FIG. In the noise current absorber 2c shown in this figure, the ferrite core is divided into two parts, a ferrite core 6a and a ferrite core 6b, which are respectively covered by the storage cases 18a and 18b. This takes into consideration ease of attachment to the cable 4. In this figure, the cable 4 is seen through. And the conductor 8c is the conductor 8b
Similarly to the case described above, the plate spring has the function of a leaf spring, and the urging force acts in a direction to separate the ferrite core 6b from the storage case 18b.

As a result, the bonding pressure of the ferrite cores 6a and 6b is applied, and the ferrite cores 6a and 6b exhibit a desired noise removing effect. Further, the cable can be held by the pressure of the conductor 8c. Also, noise current absorbers 2a, 2b
Similarly to the above, the conductor 8c has excellent frequency characteristics.

Although the conductive pairs 8b and 8c of the noise current absorbers 2b and 2c are partially disconnected, the cuts are closed by attaching the noise current absorbers 2b and 2c to the cable 4. In a state. Fourth Embodiment FIG. 4A shows a noise current absorber 2d according to a fourth embodiment of the present invention. In the noise current absorber 2d, the magnetic material is divided into a ferrite core 6c and a ferrite core 6d, and is protected by the storage case 20a and the storage case 20b during use. And this storage case 20
A conductor 8d 'and a conductor 8d''each having a substantially U-shape are provided on the inside of each of the storage cases 20a and 20b.
When the ferrite cores 6c and 6d are covered with b, the conductor 8d '
8d '' comes into contact to form a loop.

The noise current absorbing device 2d also exhibits excellent frequency characteristics, similarly to the noise current absorbing devices 2a to 2c. Fifth Embodiment FIG. 4B shows a noise current absorber 2e according to a fifth embodiment of the present invention. In the noise current absorber 2e,
The magnetic material is divided into a vertically long U-shaped ferrite core 6e and a ferrite core 6f. The two conductors 8e sandwich the ferrite cores 6e and 6f so as not to separate from each other. As shown in FIG. 4C, the conductor 8e is a holding piece 24 for holding the ferrite cores 6e and 6f.
a and 24b, and an arm 22 connecting the inner and outer circumferences of the ferrite cores 6e and 6f is provided between them. Although the arm 22 has a notch, they are in contact with each other and form a loop-shaped conductor that connects the inner and outer circumferences of the ferrite cores 6e and 6f.

Such a noise current absorber 2e also exhibits excellent frequency characteristics, similarly to the noise current absorbers 2a to 2d. The noise current absorber 2e is used for absorbing noise of a flat cable. [Others] The embodiments of the present invention have been described above. However, the present invention is not limited to these embodiments and can be implemented in various embodiments.

For example, the conductor has a wire or sheet metal bent structure, but various forms and forming methods can be applied if a conductive material is formed in a loop shape. Specifically, it may be realized by a conductive tape, a paint, an adhesive, or a conductive material may be formed on a magnetic material by sputtering.

The number of conductors is also determined by noise current absorbers 2a to 2d.
It is not limited to one such as described above or two such as the noise current absorber 2e. For example, three or more conductors 8f may be provided like the noise current absorber 2f in FIG. FIG.
The area occupied by the conductor 8g may be increased in accordance with the high-frequency countermeasure effect desired to be obtained like the noise current absorber 2g of (b). Alternatively (or in addition to the above), the conductor 8h and the variable resistor 28 are combined to change the resistance of the conductor as shown in the noise current absorber 2h in FIG. It can be changed.

The magnetic material may be other than ferrite. For example, a ferrite powder mixed with plastic, synthetic rubber, or the like, a metal core of silicon steel, a dust core of molybdenum, or the like can be used, but not limited to this.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a noise current absorber 2a of the present invention and a sample used in an experiment.

FIG. 2 is a graph for comparing frequency characteristics of the noise current absorber of the present invention and a conventional noise current absorber.

FIG. 3 is a perspective view showing a second embodiment and a third embodiment of the present invention.

FIG. 4 is a perspective view showing a fourth embodiment and a fifth embodiment of the present invention.

FIG. 5 is a perspective view showing another embodiment of the present invention.

[Explanation of symbols]

 2a to 2h: Noise current absorber 4: Cable (electric wire) 6, 6a to 6f: Ferrite core (magnetic material) 8a to 8h: Conductor (conductor for noise current absorber) 20a, 20b: Storage case 24a, 24b … Nipping piece

Claims (8)

[Claims] 1. A substantially cylindrical magnetic body surrounding an outer peripheral portion of an electric wire, and at least an integral conductor formed in a loop shape over the inner and outer circumferences of the magnetic body. Noise current absorber. 2. The noise current absorber according to claim 1, wherein the conductor is configured as a leaf spring for urging the surrounded electric wire vertically in an axial direction. Noise current absorber. 3. The noise current absorbing device according to claim 1, wherein the magnetic body is divided into two by a surface along an axial direction, and the conductor is divided into two. A noise current absorbing device characterized in that the magnetic material also serves as a holding device for holding the magnetic body in a state in which it can not be detached from a state surrounding the electric wire. 4. The noise current absorbing device according to claim 1, further comprising a storage case for storing the magnetic material, wherein the conductor is formed in the storage case. A noise current absorber, wherein when the magnetic body is stored in a storage case, the magnetic body is positioned over an inner circumference and an outer circumference of the magnetic body. 5. A conductor for a noise current absorber used together with a substantially cylindrical magnetic body surrounding an outer peripheral portion of an electric wire, wherein the conductor is formed in a loop shape over an inner periphery and an outer periphery of the magnetic body. 6. The noise current absorber according to claim 5, wherein the conductor is configured as a leaf spring for urging the surrounded electric wire vertically in an axial direction. Conductor. 7. The conductor for a noise current absorber according to claim 5, wherein the conductor is used together with the magnetic body divided into two along a surface along an axial direction, and the magnetic body surrounds the electric wire. A conductor for a noise current absorbing device, which also serves as a holding device for holding the noise current absorbing device. 8. The conductor for a noise current absorber according to claim 7, wherein a cross section perpendicular to the axis is rectangular, and the magnetic field is divided into two by the surface parallel to any side of the rectangle. A conductor for a noise current absorber, which is used together with a body and comprises a holding piece for holding the magnetic body from a direction perpendicular to the surface.