JP2016066718A - Noise-reducing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress magnetic saturation without reducing an impedance value.SOLUTION: A noise-reducing member 1 comprises: a magnetic material 11 having a through-hole 11a in which a power supply cable 3 is inserted; a conductor line 13 wound around the magnetic material 11 through the through-hole 11a; and a resistor 15 terminating the conductor line 13. The magnetic material 11 is arranged so that its effective cross section is within a range of 42-158 mm, and the effective magnetic path length is within a range of 34-111 mm. The conductor line 13 is wound around the magnetic material 11 by at least one turn, and the resistor 15 has a resistance value within a range of 98-102 Ω. Thus, magnetic saturation can be suppressed without reducing an impedance value at a frequency component of 150 kHz.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a noise reduction member for reducing noise generated from electric wires.

  In Japanese Patent Laid-Open No. 2000-353622 (Patent Document 1), a noise current flowing through a cable by causing a pair of ferrite cores formed in a semi-cylindrical shape to abut each other and inserting a cable of an electronic device or the like inside. A noise reduction member configured to absorb the is described.

  In this noise reduction member, by restricting the relative movement at the contact surfaces of the pair of ferrite cores, the ferrite core prevents the cross-sectional area of the closed circuit from being reduced, thereby realizing a high impedance value and reducing the noise. We are trying to improve.

JP 2000-353622 A

  By the way, in order to obtain a high noise reduction effect, a high impedance value is required, but a magnetic material having a high impedance value is likely to cause magnetic saturation. When the current flowing through the cable is direct current, the magnetic saturation becomes significant. Therefore, in order to reduce the noise superimposed on the direct current, it is necessary to achieve both a high impedance value and suppression of magnetic saturation. The above-mentioned publication does not mention anything in this respect, and there is still room for improvement.

  The present invention has been made in view of the above, and an object of the present invention is to provide a technique capable of suppressing magnetic saturation without reducing the impedance value.

  As a result of diligent research in order to achieve the above-described object, the present inventors have found that in a noise reduction member configured by winding a conductor wire around a magnetic material and connecting a resistor to both ends of the conductor wire, It has been found that magnetic saturation can be suppressed without lowering the impedance value in a predetermined frequency band by setting each of the shape dimension, the number of windings of the conductor wire, and the resistance value of the resistor to a predetermined value. It came to be completed.

According to a preferred embodiment of the noise reducing member of the present invention, a magnetic body having an insertion hole for inserting an electric wire, a conductor wire wound around the magnetic body through the insertion hole, and a resistance for terminating the conductor wire And a body. In the noise reduction member, the magnetic body is configured so that the effective cross-sectional area is in the range of 42 to 158 mm ² and the effective magnetic path length is in the range of 34 to 111 mm. The conductor wire is configured to be wound at least once around the magnetic body. And a resistor is comprised so that it may become the range of 98-102 ohms preferably, so that a resistance value may be in the range of 50-200 ohms. The “electric wire” in the present invention typically corresponds to a power cable, but preferably includes a signal cable and a control cable. The “effective cross-sectional area” in the present invention corresponds to the effective cross-sectional area of the magnetic path as defined in JIS C2560-1992. Furthermore, the “effective magnetic path length” in the present invention corresponds to the effective length of the magnetic path as defined in JIS C2560-1992.

  In general, it is a frequency component on the low frequency side that causes a problem with noise superimposed on a direct current. However, according to the present invention, the lowest frequency component in the frequency band established in the EMC standard for power supplies is used. At a certain 150 kHz, magnetic saturation can be suppressed when the magnetomotive force is in the range of 1 to 2 AT, and the impedance value in the frequency band hardly decreases. Thereby, the noise in the power supply line through which a large current flows, such as an automobile or industrial equipment, an inverter device, or the like can be effectively reduced.

  According to the present invention, it is possible to suppress magnetic saturation without reducing the impedance value.

It is an external view which shows the external appearance of the noise reduction member 1 which concerns on embodiment of this invention. It is the magnetic permeability characteristic figure which measured the magnetic permeability of the noise reduction member 1 which concerns on this Embodiment, and the noise reduction member which does not have a conductor wire or a resistor over 0.01-10AT in the magnetomotive force by a direct current. . It is the impedance characteristic figure which measured the impedance value of the noise reduction member 1 which concerns on this Embodiment, and the noise reduction member which does not have a conductor wire or a resistor over frequency 0.01MHz (10kHz)-1000MHz (1GHz). .

  Next, the form for implementing this invention is demonstrated using an Example.

  The noise reduction member 1 according to the embodiment of the present invention is attached to the outer periphery of the power cable 3 of the power source (battery) of the automobile so as to absorb and reduce noise superimposed on the direct current flowing through the power cable 3. The magnetic body 11, a conductor wire 13 wound around the magnetic body 11, and a resistor 15 that terminates the conductor wire 13 are provided. The noise reduction member 1 corresponds to the “noise reduction member” in the present invention, the magnetic body 11 corresponds to the “magnetic body” in the present invention, the conductor wire 13 corresponds to the “conductor wire” in the present invention, The resistor 15 is an example of an implementation configuration corresponding to the “resistor” in the present invention. Moreover, the power cable 3 is an example of the implementation structure corresponding to the "electric wire" in this invention.

The magnetic body 11 is constituted by a substantially cylindrical ferrite core, and a through hole 11a penetrating in the axial direction is formed inside. The magnetic body 11 has an outer diameter of 20 mm, an inner diameter of 10 mm, and a length of 10 mm. That is, the magnetic body 11 is configured to have an effective cross-sectional area of 42 to 54 mm ² and an effective magnetic path length of 43 to 44 mm. The through-hole 11a is an example of the implementation structure corresponding to the "insertion hole" in this invention.
The effective area and the effective magnetic path length are calculated from the outer diameter, inner diameter and length of the magnetic material, as is clear from the definition of JIS C2560-1992. In the present invention, the outer diameter and inner diameter of the magnetic material are calculated. Since the maximum length has a tolerance of 0.6 mm, the effective area and the effective magnetic path length have a certain width.

  The conductor wire 13 is mainly composed of a copper wire and has a wire diameter of 0.5 mm. As shown in FIG. 1, the conductor wire 13 is inserted through the through hole 11 a of the magnetic body 11 and is wound once in a loop over the inner periphery and the outer periphery of the magnetic body 11.

  The resistor 15 is connected to both ends of the conductor wire 13. The resistor 15 has a resistance value of 100Ω.

Next, the magnetic permeability characteristic and the impedance characteristic in the noise reduction member 1 thus configured will be described. FIG. 2 shows the magnetic permeability obtained by measuring the magnetic permeability of the noise reducing member 1 according to the present embodiment and the noise reducing member having no conductor wire or resistor over a magnetomotive force of 0.01 to 10 AT due to a direct current. FIG. 3 is a characteristic diagram, and FIG. 3 shows that the impedance value between the noise reduction member 1 according to the present embodiment and the noise reduction member having no conductor wire or resistor is set to a frequency of 0.01 MHz (10 kHz) to 1000 MHz (1 GHz). It is the impedance characteristic figure measured over it.
In FIG. 2 and FIG. 3, “Noise reduction member 1 according to the present embodiment” is represented by “A”, and “Noise reduction member having no conductor wire or resistor” is “B”. Represented by

  As shown in FIG. 2, the magnetic permeability μ of the noise reduction member (B) that does not have the conductor wire 13 and the resistor 15 is gradually reduced from the value of about 0.1 AT. On the other hand, in the noise reduction member 1 (A) according to the present embodiment, as described above, the magnetic permeability μ starts to decrease in magnetomotive force from a value of about 0.1AT, but has a high magnetic permeability over a value of 0.1 to 2AT. As shown, the decreasing tendency of the magnetic permeability μ temporarily stops in the range of the value 1 to 2AT. That is, the decrease in the magnetic permeability μ is suppressed when the magnetomotive force is in the range of 1 to 2AT. FIG. 2 shows the magnetic permeability characteristics at 150 kHz, which is the lowest frequency component in the frequency band established by the EMC standard relating to the power supply.

  On the other hand, the noise reduction member (B) that does not have the conductor wire 13 and the resistor 15 and the noise reduction member 1 (A) according to the present embodiment do not show a large difference as shown in FIG. That is, the impedance value does not decrease depending on the presence or absence of the conductor wire 13 or the resistor 15.

That is, according to the noise reduction member 1 (A) according to the present embodiment, magnetic saturation can be suppressed within a frequency range of 1 to 2 AT at a frequency component of 150 kHz, and in the frequency band. The impedance value hardly decreases. Thereby, the noise in the power supply line through which a large current flows, such as an automobile or an industrial device, an inverter device, or the like can be effectively reduced.
In addition, although the conductor wire 13 in the noise reduction member 1 described above is wound around the magnetic body once, it may be wound twice or three times. In this case, the magnetic saturation can be most suppressed when the number of windings is one.
Moreover, although the above-mentioned resistor 15 is set to 100Ω, in the present invention, it has also been confirmed that the same result can be obtained in the range of 50 to 200Ω. Furthermore, it was confirmed that if the resistance value is in the range of 98 to 102Ω, it is possible to suppress the magnetic saturation without substantially reducing the impedance value.
In addition, when it deviated from the above-mentioned range, it was not possible to suppress the magnetic saturation without reducing the impedance value.

(Correspondence between each component of the embodiment and each component of the present invention)
This embodiment shows an example for carrying out the present invention. Therefore, the present invention is not limited to the configuration of the present embodiment.

In the above embodiment, the magnetic body 11 has an outer diameter of 20 mm, an inner diameter of 10 mm, and a length of 10 mm, an effective cross-sectional area of 42 to 54 mm ² , and an effective magnetic path length of 43 to 44 mm. However, in the present invention, in addition to this, a magnetic body having an outer diameter of 16 mm, an inner diameter of 8 mm, a length of 16 mm, an effective cross-sectional area of 54 to 69 mm ² , and an effective magnetic path length of 34 to 35 mm, The same effect as described above was confirmed for a magnetic body having an outer diameter of 47 mm, an inner diameter of 27 mm, a length of 15 mm, an effective cross-sectional area of 134 to 158 mm ² , and an effective magnetic path length of 109 to 111 mm.

DESCRIPTION OF SYMBOLS 1 Noise reduction member 3 Power supply cable 11 Magnetic body 11a Through hole (insertion hole)
13 Conductor wire 15 Resistor

Claims (2)

A magnetic body having an insertion hole for inserting an electric wire;
A conductor wire wound around the magnetic body through the insertion hole;
A resistor for terminating the conductor wire;
With
The magnetic body is configured to have an effective area of 42 to 158 mm ² and an effective magnetic path length of 34 to 111 mm.
The conductor wire is configured to be wound at least once around the magnetic body,
The resistor is configured to have a resistance value in a range of 50 to 200Ω.   The noise reducing member according to claim 1, wherein the resistance value of the resistor is in a range of 98 to 102Ω.

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