JP2921049B2 - Electromagnetic interference prevention element - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic interference preventing element for preventing electromagnetic interference (EMI) in electric wires such as signal lines and power lines used in digital equipment and the like. is there.

[Conventional technology]

Electromagnetic interference prevention elements in digital equipment, etc., include a normal mode inductor that removes normal mode noise that occurs in individual signal lines and power supply lines, and a common mode inductor that removes common mode noise that occurs in the entire system. Things have been suggested.

FIG. 4 is an exploded perspective view showing a conventional electromagnetic interference preventing element disclosed in, for example, Japanese Utility Model Publication No. 1-40230. In the figure, (1) is an electric wire (insulated wire) such as a signal line and a power supply line, (2) is a tubular body formed by winding an amorphous magnetic strip into a tube, and (3) is an electric wire (1) and a tubular body. A cylindrical ferrite core through which the combination of (2) is inserted.

In the above-described electromagnetic interference prevention element, the tubular body (2) functions as a normal mode inductor, and the cylindrical ferrite core (3) functions as a common mode inductor, so that normal mode and common mode noise flowing through the electric wire (1) are reduced. Reduce.

[Problems to be solved by the invention]

Since the conventional electromagnetic interference prevention element is configured as described above, there are problems that it takes time and effort to form the tubular body (2) by winding and becomes large, and the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to obtain a small-sized electromagnetic interference prevention element which is easy to manufacture by integrating a normal mode inductor and a common mode inductor.

[Means for solving the problem]

 The present invention is the following electromagnetic interference prevention element.

(1) A magnetic core made of a magnetic material integrally molded, a common mode inductor hole provided in the magnetic core so that a plurality of electric wires are inserted all together, and a plurality of holes inserted in the common mode inductor hole. A normal mode inductor hole provided separately from the magnetic core so as to insert wires one by one, wherein the normal mode inductor hole and the common mode hole form an independent magnetic path for each mode; In the present invention, the electric wires mean all electric wires that generate noise or are externally introduced, such as signal lines and power supply lines. Further, the magnetic material means all magnetic materials having a noise absorption characteristic, such as ferrite.

(Operation)

In the electromagnetic interference prevention element of the present invention, the normal mode inductor is formed by passing one wire at a time through the normal mode inductor hole provided in the integrally formed magnetic core, and all the wires are collectively used for the common mode inductor. By passing through a hole, a common mode inductor is formed, thereby forming an independent magnetic path to reduce normal mode and common mode noise flowing through electric wires such as signal lines and power lines.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1 to 3 are perspective views showing different embodiments.

In FIGS. 1 and 2, (11) is a magnetic core integrally formed of ferrite, and (12) is separated into the magnetic core (11) so that a plurality of electric wires (1) are inserted one by one. It is a provided hole for normal mode inductor,
In FIG. 1, one is provided on each of the left and right sides, and in FIG. 2, three are provided on each of the left and right sides. (13) is a common mode inductor hole provided in the magnetic core (11) so as to collectively insert the plurality of electric wires (1) inserted into the normal mode inductor hole (12). Hole for normal mode inductor (12) and hole for common mode inductor (13)
Are arranged in a direction perpendicular to the direction.

In the electromagnetic interference prevention element configured as described above, the normal mode inductor is formed by passing the electric wires (1) one by one through the normal mode inductor hole (12) provided in the magnetic core (11), By passing all the wires (1) together through the common mode inductor hole (13), a common mode inductor is formed, and the wires (1)
Normal mode and common mode noise flowing through the circuit are reduced.

In FIG. 3, (14) is a conductor, and a magnetic core (11)
By being buried in the inside, a normal mode inductor hole (12) provided separately and a common mode inductor hole (13) provided in parallel and close to each other are formed. The conductor (14) has a hole (1
In 2), they are separated and buried one by one. (15) is a terminal formed at the end of the conductor (14).

The above-mentioned electromagnetic interference prevention element is used by connecting the electric wire (1) or an electronic component to the terminal (15), and can be surface-mounted, and reduces noise as in FIGS. 1 and 2.

In the above embodiment, the rectangular magnetic core (11) is used.
Its shape is not limited. Further, the positions, directions, numbers, and the like of the holes (12) and (13) are not limited to those in the above embodiment, and can be changed.

〔The invention's effect〕

According to the present invention, since the hole for the normal mode inductor and the hole for the common mode inductor are provided in one integrally formed magnetic core, the normal mode inductor and the common mode inductor are integrated, without winding the tubular body. A small electromagnetic interference prevention element that can be easily manufactured is obtained. Also,
Since the holes for the normal mode inductor and the holes for the common mode inductor are arranged at right angles, there is an effect that the magnetic material is not saturated.

[Brief description of the drawings]

1 to 3 are perspective views of another embodiment, and FIG. 4 is an exploded perspective view of a conventional example. In the respective drawings, the same reference numerals indicate the same or corresponding parts, and (1)
Is an electric wire, (11) is a magnetic core, (12) is a hole for a normal mode inductor, (13) is a hole for a common mode inductor, (1
4) is a conductor, and (15) is a terminal.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoto Oka 2-14-40 Ofuna, Kamakura City, Kanagawa Prefecture Inside the Lifestyle Systems Research Laboratories, Mitsubishi Electric Corporation (72) Shoji Fujiwara 2-14, Ofuna, Kamakura City, Kanagawa Prefecture No. 40, Mitsubishi Electric Corporation Living System Laboratory (56) References JP-A-2-91904 (JP, A) JP-A 1-162312 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01F 17 / 06,37 / 00,17 / 04 H01F 27/28 H03H 7/09

Claims (1)

(57) [Claims] 1. A magnetic core made of an integrally molded magnetic material, a common mode inductor hole provided in the magnetic core so that a plurality of electric wires are inserted all at once, and a common mode inductor hole inserted into the common mode inductor hole. A normal mode inductor hole provided separately from the magnetic core so that a plurality of electric wires are inserted one by one; the normal mode inductor hole and the common mode hole form an independent magnetic path for each mode; An electromagnetic interference prevention element, which is arranged in a perpendicular direction so as to form.