JPH05114517A - Magnetic material core for signal line filter - Google Patents

Abstract

PURPOSE:To make noise elimination effect almost uniform, by making almost uniform impedance characteristics in the vicinity of a pin insertion hole formed at each position of a magnetic material core which is mounted on a terminal connector of a signal line cable and forms a signal line filer. CONSTITUTION:A plurality of pin insertion holes into which connector pins are inserted are formed in a magnetic material core 1 to be mounted on a connector for signal line. The diameters of pin insertion holes 2a, 2b at the end portion are made larger than those of the insertion holes 2c on the central part side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mounted on a connector of a terminal portion of a signal line cable for connecting electronic equipment to form a signal line filter for absorbing noise flowing through the signal line cable from inside and outside the electronic equipment. The present invention relates to a magnetic core for signal line filters.

[0002]

2. Description of the Related Art As a method of absorbing noise flowing in a signal line cable, a porous magnetic material core made of ferrite or the like is attached to a terminal connector of the signal line cable, and the high impedance characteristic of this magnetic material is utilized. Techniques for absorbing noise are known (for example, Shokai 6
2-171173).

FIG. 6A is a plan view showing a magnetic core for a signal line filter to be attached to a conventional connector,
(B) is a sectional view taken along the line AA. In the figure, 1 is a magnetic core made of a magnetic material such as ferrite, and has a large number of pin insertion holes 2 in the thickness direction.

FIG. 2 is a sectional view corresponding to BB in FIG. 6A showing a signal line filter in which this porous magnetic core is mounted on a connector. In the figure, 3 is a signal line filter, in which the magnetic core 1 is mounted so that the connector pin 5 of the signal line connector 4 is inserted into the pin insertion hole 2 of the magnetic core 1.

Conventionally, when the noise flowing in such a signal line cable is absorbed by using a magnetic material such as ferrite, the same number of pin insertion holes 2 as the connector pins 5 are formed in the connector 4 of the signal line cable terminal portion. A high impedance is provided by mounting the porous magnetic core 1 having the same. And this impedance against noise current,
Since it acts as a resistance component, the magnetic core 1 absorbs noise and dissipates it as heat, thereby acting as a signal line filter.

[0006]

However, the magnetic core 1 as described above is used by being incorporated in the signal line connector 4 to form the signal line filter 3, but the position of the pin insertion hole 2 is not limited to this. There is a difference in the noise removing effect, and it is not possible to obtain a uniform noise removing effect.

That is, when a noise current flows through the connector pin 5 inserted into the pin insertion hole 2 of the magnetic core 1, a magnetic path is formed in the magnetic core 1 around the pin insertion hole 2,
Although noise is absorbed, when a noise current flows through the plurality of connector pins 5 at the same time, the magnetic paths centering on the pin insertion holes 2 interfere with each other. The interference of the magnetic path is large near the pin insertion hole 2 on the center side and small near the pin insertion hole 2 at the end. Therefore, the pin insertion hole 2 on the center side has a small effective magnetic path length, and the pin insertion hole 2 on the end has a large effective magnetic path length, which causes different impedance characteristics and different noise removal effects. It was

The present invention has been made to solve the above problems, and a signal line filter capable of making the impedance characteristics in the vicinity of the pin insertion holes formed at each position substantially uniform and making the noise removal effect substantially the same. The purpose is to obtain a magnetic core for use.

[0009]

The present invention is the following magnetic core for signal line filters. (1) In a magnetic core for mounting on a terminal connector of a signal line cable to form a signal line filter, the magnetic core has a plurality of pin insertion holes into which connector pins are inserted, and pin insertion at an end is performed. The hole is a magnetic core for signal line filters that has a larger diameter than the pin insertion hole on the center side. (2) In a magnetic core for attaching to a terminal connector of a signal line cable to form a signal line filter, the magnetic core has a plurality of pin insertion holes into which connector pins are inserted, and each pin insertion hole is A magnetic core for a signal line filter, wherein a taper is formed in the thickness direction of the magnetic core, and the small diameter portion of the pin insertion hole at the end has a larger diameter than the small diameter portion of the pin insertion hole on the central side.

[0010]

In the magnetic core for a signal line filter according to claim 1 of the present invention, since the pin insertion hole at the end portion has a larger diameter than the pin insertion hole at the central portion side, the inserted pin from the connector pin The distance to the magnetic core increases, which changes the impedance characteristics and reduces the noise removal effect. On the other hand, the pin insertion hole on the center side has a short magnetic path length due to interference, and the noise removing effect is small. Therefore, these cancel each other out, the impedance characteristics become substantially uniform, and the noise removing effect is almost averaged.

In the magnetic core for a signal line filter according to claim 2 of the present invention, since the pin insertion hole is tapered in the thickness direction, it is easy to insert the connector pin and the mountability is excellent. Since the diameter of the small diameter portion of the pin insertion hole at the end portion is large, the impedance characteristic becomes substantially uniform, and the noise removal effect is almost averaged.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. Example 1 FIG. 1 shows a magnetic core of Example 1, (a) is a plan view,
2B is a sectional view taken along line CC of FIG. 2, and FIG. 2 is a sectional view taken along line D-D showing the usage thereof. In the figure, the same reference numerals as those in FIG.

The magnetic core 1 has the same structure as the conventional one.
A large number of pin insertion holes 2 are formed in the thickness direction and are arranged in two rows in a staggered pattern. Of these pin insertion holes 2, the pin insertion holes 2a and 2b located at the ends are formed with a diameter 1.1 to 1.2 times larger than the diameter of the pin insertion hole 2c located on the center side. Has been done. The pin insertion hole 2a located at the end is formed to have a larger diameter than the pin insertion hole 2b located near the center. These pin insertion holes 2 are formed with different diameters so that the noise absorbing effect is substantially constant.

The magnetic core 1 formed as described above is
As shown in FIG. 2, the connector pin 5 of the signal line connector 4 is mounted so as to be inserted into the pin insertion hole 2 so as to provide impedance, and is used for noise removal.

When a noise current flows through the connector pin 5 in this state, a magnetic path is formed around the pin insertion hole 2 in the magnetic core 1 and the noise is absorbed. At this time, since the magnetic paths centering on the pin insertion holes 2 interfere with each other, the effective magnetic paths formed around the pin insertion holes 2 are different, and the magnetic paths of the pin insertion holes 2a and 2b located at the ends are different. The path, especially the magnetic path of the pin insertion hole 2a located at the extreme end is long because there is little interference.

On the other hand, the pin insertion holes 2a, 2 located at the ends.
Since b has a larger diameter than the pin insertion hole 2c located on the center side, the distance from the connector pin to the magnetic core 1 becomes large, the impedance characteristic changes, and the noise removal effect decreases. Therefore, these cancel each other out, the impedance characteristics become substantially uniform, and the noise removal effect of the entire pin insertion hole 2 is almost averaged.

Since the noise removing effect is proportional to the magnetic path length and inversely proportional to the square of the diameter, the diameters of the pin insertion holes 2a and 2b at the ends are generally the diameters of the pin insertion holes 2c at the center side. Although it is 1.1 to 1.2 times the actual value, it depends on the size and shape of the hole, the material of the magnetic substance, the current value, etc. It is desirable to check with.

Example 2 FIG. 3 shows a magnetic core of Example 2, (a) is a plan view,
FIG. 4B is a sectional view taken along line EE, and FIG. 4 is a sectional view taken along line FF showing the usage state. In this embodiment, the pin insertion hole 2 is tapered in the thickness direction of the magnetic core 1. The small diameter part of the pin insertion holes 2a, 2b at the end has a diameter 1.1 to 1.2 times larger than the small diameter part of the pin insertion hole 2c at the central part side. The diameter of the large diameter portion of each pin insertion hole 2 is the same.

As shown in FIG. 4, the magnetic core 1 configured as described above is mounted by inserting the connector pin 5 into the pin insertion hole 2 from the large diameter portion side. At this time, the connector pin 5 can be easily inserted, and the mountability becomes good even in the case of a small connector. And the pin insertion hole 2a at the end,
Since the small diameter portion of 2b has a larger diameter than the small diameter portion of the pin insertion hole 2c on the center side, the impedance characteristics are substantially uniform and the noise removal effect is almost averaged.

Example 3 FIG. 5 shows the magnetic core of Example 3 and the line EE in FIG.
FIG. In this embodiment, the pin insertion hole 2 is configured similarly to the second embodiment except that the taper is formed in the vicinity of the opening portions on both sides, and has the same operation and effect.

In the above description, the magnetic core 1
Also, the shape, structure, material and the like of the pin insertion hole 2 are not limited to those of the embodiment and can be changed.

[0022]

In the magnetic core for a signal line according to claim 1 of the present invention, the diameter of the pin insertion hole at the end portion is made larger than the diameter of the pin insertion hole at the central portion side. The impedance characteristics in the vicinity can be made substantially uniform, and the noise removal effect can be almost averaged.

In the magnetic core for a signal line according to claim 2 of the present invention, the pin insertion hole has a taper, and the diameter of the small diameter portion of the pin insertion hole at the end is the same as that of the small diameter portion of the pin insertion hole on the central side. Since the diameter is larger than the diameter, in addition to the above effect, the mountability can be improved even when mounted on a small-sized or multi-pin connector.

[Brief description of drawings]

1A and 1B show a magnetic core of Example 1, where FIG. 1A is a plan view and FIG. 1B is a sectional view taken along line CC.

FIG. 2 is a cross-sectional view corresponding to DD of FIG. 1 and BB of FIG. 6 showing a usage state of magnetic cores of Example 1 and a conventional example.

3A and 3B show a magnetic core of Example 2, where FIG. 3A is a plan view and FIG. 3B is a sectional view taken along line EE.

FIG. 4 is a cross-sectional view taken along line FF of FIG. 3 showing a usage state of a magnetic core of Example 2.

5 is a cross-sectional view taken along line EE of FIG. 3 showing a magnetic core of Example 3. FIG.

FIG. 6 shows a conventional magnetic core, (a) is a plan view,
(B) is the AA sectional view.

[Explanation of symbols] 1 magnetic core 2, 2a, 2b, 2c pin insertion hole 3 signal line filter 4 signal line connector 5 connector pin

Claims (2)

[Claims] 1. A magnetic core for mounting on a terminal connector of a signal line cable to form a signal line filter, wherein the magnetic core has a plurality of pin insertion holes into which connector pins are inserted. The magnetic core for a signal line filter, wherein the pin insertion hole has a larger diameter than the pin insertion hole on the center side. 2. A magnetic core for mounting on a terminal connector of a signal line cable to form a signal line filter, wherein the magnetic core has a plurality of pin insertion holes into which connector pins are inserted, and each pin is inserted. The hole is tapered in the thickness direction of the magnetic core, and the small diameter part of the pin insertion hole at the end has a larger diameter than the small diameter part of the pin insertion hole at the center side. For magnetic core.