JPH10275994A - Core for emi countermeasure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to control the effect of the removal of noise arbitrarily and effectively by a core for EMI countermeasure and moreover, to enable the reuse of the core, by a method wherein the core is formed by enabling a high-permeability and high-receptivity magnetic material to mix in an insulate martial, which has a prescribed elasticity and a prescribed viscosity and moreover, is solidified when heat, ultraviolet rays or the like irradiates the insulative material. SOLUTION: In the case where a core for EMI countermeasure is applied to an interface cable, the core 1 is formed by enabling a ferrite to mix a photosetting plastic as a magnetic material. The photosetting plastic is used as a fiber, for example, in a dental treatment, is normally formed into a clay shape, has a feature to solidify when ultraviolet rays irradiates the plastic and is normally an insulator. The ferrite is a magnetic material and the permiability of the ferrite is high, but the receptivity of the ferrite is also high and the ferrite is normally regarded as an insulator. Accordingly, even of ferrite powder is included in a case body for an information processing device or the like, a short-circuit or the like can never be caused in the device or the like. Moreover, as the core 1 is formed into the clay shape, the core can be simply mounted also to any cable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interface cable for an information processing device, a wire harness inside the information processing device, etc., and an interface cable for an information processing device and a wire inside the information processing device. The present invention relates to a core for removing harmful electromagnetic waves radiated from a harness or the like, and particularly to an EMI (ElectroMagnet).
The present invention relates to an EMI countermeasure core suitable for use at the time of cut and try (trial) at a test site (test site) or the like.

[0002]

2. Description of the Related Art Electromagnetic noise (hereinafter simply referred to as "noise") radiated from an interface cable of an information processing device or a wire harness in the information processing device.
In order to remove the noise, a component called a core attached to a cable is used, which is often used when noise suppression of an information processing device is performed at an EMI test site, and is also applied to mass-produced products.

[0003] The principle of the core is that a magnetic material having a high magnetic permeability is wound around an interface cable, a wire harness, or the like.
The magnetic flux generated by the noise current is passed through the magnetic body, and the magnetic resistance of the magnetic body is used to convert the energy of the magnetic field due to the noise current into thermal energy to remove the noise.

Generally, the effect of the core (ie, the noise removing effect) is substantially proportional to the cross-sectional area of the core (the area through which the magnetic flux due to the noise current can pass), and the average magnetic path length of the core (the magnetic flux passes through the core). The length of the case).

In general, it is said that the most effective insertion of a core, such as an interface cable, coming out of a housing of an information processing apparatus or the like into a bushing shape at an outlet of the housing.

[0006] There are roughly the following four methods as conventional techniques for EMI countermeasure cores.

[0007] (1) Method of using a ready-made split core: As shown in a perspective view in FIG. 6, this is a method of taking measures against noise by using a ready-made split core 1 for a cable 2. As shown, the split core 1 has a cylindrical core split into two.

(2) Method using a core with an elastic material inside (see Japanese Utility Model Laid-Open No. 2-122517): As shown in a sectional view in FIG. In this method, the elastic body 12 is provided, and the cable 2 is fixed by the elastic body 12. In the method using an off-the-shelf core, when applied to a cable extremely thinner than the inner diameter of the core, a means (clamp means) for fixing the core to the cable is required. In this method, the elastic body 12 is provided. This eliminates the need for special fixing means.

(3) Method using a tape-shaped core (see Japanese Patent Application Laid-Open No. Hei 5-327265): As shown in a perspective view in FIG. 8, a magnetic material is mixed into a resin such as a tape, and the tape 13 is connected to a cable. This is a method of removing noise by wrapping around two. By changing the width of the tape 13 and the number of windings, the effect of noise removal can be arbitrarily adjusted.

(4) Method using a bushing with a ferrite core (see JP-A-3-224299): FIG.
As shown in FIG. 9, a ferrite core 24 (see FIG. 9C) is built in a nut 30 constituting the bushing 22. 9A is a perspective view, FIG. 9B is a side view, and FIG. 9C is a cross-sectional view taken along line AA in FIG. 9B.

Generally, it is said that it is most effective to insert a core of an interface cable or the like coming out of a housing of an information processing device or the like into a bushing shape at an outlet of the housing, so that a high noise removal effect is obtained. Is obtained. Also, core 2
4 is replaceable, and by replacing the core 24, the effect of noise removal can be adjusted arbitrarily.

[0012]

However, each of the four methods described as the prior art has the following problems.

(1) Method of using a pre-made split core: In this case, the outer diameter of the core and the inner diameter of the hole through which the interface cable and the like pass are determined in advance. Therefore, it is necessary to fix a cable that is extremely thin compared to the inner diameter.
When inserting a core as a measure against noise at a test site or the like, the core must be fixed with a cable tie or the like, which is inconvenient.

Further, since the core cannot be passed through an interface cable or the like that is thicker than the core inner diameter in the first place, in an EMI test site or the like where the types of prepared cores are limited, even if it is desired to insert the core, It may not be possible.

Further, since the outer diameter of the core is predetermined, there is also a problem that the core cannot be inserted depending on the space where the core is inserted.

(2) Method of using a core having an elastic material inside: As in the method of using a ready-made split core in the above (1), the core cannot pass through an interface cable or the like that is thicker than the inner diameter. Therefore, in an EMI test site or the like where the types of prepared cores are limited, it may not be possible to insert a core.

Furthermore, since the outer diameter of the core is predetermined, there is a problem that the core cannot be inserted depending on the space where the core is inserted.

(3) Method using a tape-shaped core: This method can be easily applied by wrapping a tape around a thick cable, but when applying to an extremely thin interface cable or the like, start winding. Sometimes, it is inconvenient to start winding the tape, taking care not to open a gap between the interface cable or the like and the tape.

Also, in order to increase the cross-sectional area of the core, the number of windings must be increased, which is inconvenient in an EMI test site or the like where it is necessary to take quick and efficient noise countermeasures.

Further, the width of the tape is predetermined,
If a wide core is desired to be formed, the tape must be wound further adjacent to the single wound tape, which is inefficient.

And, depending on the properties of the tape adhesive,
There is also a problem that once used for an interface cable or the like, it cannot be reused.

(4) Method using bushing with ferrite core: Since the inner diameter of the nut is determined,
A core larger than the inner diameter of the nut cannot be built.

Further, since the inner diameter of the core (24 in FIG. 9) built in the nut is predetermined, there is a problem that it cannot be applied to an interface cable or the like having a larger diameter than the inner diameter.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and depend on the thickness of an interface cable of an information processing device, a wire harness inside the information processing device, and the space for inserting a core. Without noise, the noise removal effect can be adjusted arbitrarily and efficiently,
Another object of the present invention is to provide a core that is reusable and applicable to mass production.

[0025]

In order to achieve the above object, an EMI countermeasure core according to the present invention is provided with an insulating material having a predetermined elasticity and viscosity and solidifying when irradiated with heat or ultraviolet rays. It is characterized by being mixed with a magnetic material having high magnetic permeability and high resistivity.

In the present invention, the core is used by being attached to an external interface cable of an information processing device or the like, a wire harness inside the information processing device or the like, and further irradiated with heat or ultraviolet rays to be solidified. .

[0027]

Embodiments of the present invention will be described below. The EMI countermeasure core of the present invention, in a preferred embodiment, is a core for removing noise radiated from an interface cable of an information processing device and a wire harness in the information processing device, and has a clay-like elasticity and The present invention is characterized in that a magnetic material having a high magnetic permeability and a high electric resistivity is mixed with an insulating material having a viscosity and solidifying when irradiated with heat, ultraviolet rays, or the like.

In the present invention, the material itself is not particularly limited as long as it is an insulating material that solidifies when irradiated with heat, ultraviolet light, or the like. In a preferred embodiment, for example, a photocurable plastic or A thermosetting plastic or the like can be used.

The magnetic powder used in the present invention is not particularly limited as long as it has magnetism and high electric resistance. In a preferred embodiment, for example, ferrite is used. it can. As a material used for the magnetic powder, a material having high magnetic permeability and magnetic flux density is preferable.

As described above, in the preferred embodiment, the EMI countermeasure core of the present invention is made of an insulating material having clay-like elasticity and viscosity and solidifying when irradiated with heat or ultraviolet rays. It is made by mixing magnetic material with high magnetic susceptibility and high electric resistivity. It has clay-like elasticity and viscosity, so it can be easily attached to the interface cable of information processing equipment and the wire harness in information processing equipment. And the number of cores can be easily increased or decreased according to the noise removal effect. Also, depending on the insertion space, a thin core or a wide core can be formed,
It is also possible to create a core having an arbitrary shape other than a cylindrical shape such as a quadrangular prism or a triangular prism.

In the preferred embodiment, the EMI countermeasure core of the present invention has a feature that it solidifies when irradiated with ultraviolet light or heat. After being attached to a harness and solidified, mass production can be easily applied after confirming the effect at an EMI test site or the like.

Further, the solidification does not occur unless irradiated with heat or ultraviolet rays. Therefore, if no noise removing effect is recognized, it can be removed and reused.

[0033]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

FIG. 1 is a perspective view showing the appearance when the present invention is applied to an interface cable as a first embodiment to which the EMI countermeasure core of the present invention is applied.

Referring to FIG. 1, core 1 is made of a photocurable plastic mixed with ferrite as a magnetic material. Photocurable plastics are used, for example, as fillers for dental treatment, and are usually clay-like, have the characteristic of solidifying when irradiated with ultraviolet light, and are usually insulators. Ferrite is a magnetic substance and has high magnetic permeability but high resistivity, and is generally regarded as an insulator. Therefore, even if ferrite powder enters the housing of an information processing device or the like, a short circuit or the like cannot occur.

As shown in FIG. 1, first, the core 1 is attached to the cable 2.

(A) Since the core 1 is clay-like,
It can be easily attached to thick or thin cables.

(B) In order to increase the noise removing effect, when it is desired to increase the cross-sectional area or to form a wide core, it is possible to easily add or extend the core.

(C) In order to reduce the size of the core in terms of cost, it is easy to cut off the core to reduce the cross-sectional area and width.

(D) Further, according to the insertion space, not only a cylindrical shape but also a quadrangular prism shape or a triangular prism shape is possible.

(E) Since the solidification does not occur unless irradiated with ultraviolet rays, the core 1 can be removed and reused if there is no noise removing effect.

These features (a) to (e) are particularly effective at an EMI test site where cut and try are frequently performed.

As shown in FIG. 2, when the cable 2 is pulled out from the opening 4 of the housing 3, the core 1 is inserted into the opening 3.
By mounting the in the form of a bushing, a theoretically great noise removal effect is exhibited. Since the core 1 is made of a clay, a core matching the size of the opening 3 can be easily formed.

At the EMI test site, when noise suppression is performed using the core of the present invention, if the noise removal effect can be confirmed, as shown in FIG.
Thus, the core 1 can be solidified by irradiating the core 1 with ultraviolet rays.

Therefore, the EMI countermeasure core of the present invention can be mass-produced as it is (it can be mass-produced by solidifying after molding), and the core of the present invention is E-type.
It may be used only for the cut and try phase at the MI test site, and a conventional split core may be used for mass production.

Next, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 4 shows a second example of the EMI countermeasure core of the present invention.
FIG. 2 is a diagram illustrating an appearance when the present invention is applied to an interface cable as an example of (1).

In FIG. 4, the core 1 is obtained by mixing ferrite as a magnetic material in a thermosetting plastic.
Thermosetting plastics are usually clay-like, solidify when heated, and are usually insulators. Ferrite is a magnetic substance, has high magnetic permeability but high resistivity, and is generally regarded as an insulating part. Therefore, even if ferrite powder enters the housing of an information processing device or the like, a short circuit or the like cannot occur.

As shown in FIG. 4, the core 1 is attached to the interface cable 2 '.

In this case, (a) Since the core 1 is made of clay, it can be easily attached to a thick cable or a thin cable.

(B) In order to increase the noise removing effect, when it is desired to increase the cross-sectional area or to form a wide core, it is possible to easily add or extend the core.

(C) Further, when it is desired to reduce the size of the core due to the cost, it is easy to cut off the core to reduce the cross-sectional area and width.

(D) Further, according to the insertion space, not only a cylindrical shape but also a quadrangular prism shape or a triangular prism shape is possible.

(E) Since the solidification does not occur unless heated, the core 1 can be removed and reused if there is no noise removing effect.

The features (a) to (e) are effective at an EMI test site where cut and try is frequently performed.

In this embodiment, as in the first embodiment, it is also possible to mount it in a bushing shape on the opening of the housing.

At the EMI test site, when noise suppression was performed using the core of the present invention, if the noise removal effect was confirmed, as shown in FIG. Can be solidified.

Accordingly, the EMI countermeasure core of the present invention can be applied to mass production as it is, and the core of the present invention is used only for the cut-and-try phase at the EMI test site. A certain split core may be used.

Further, as still another embodiment of the present invention,
Ferrite powder may be mixed into the rubber latex. In this case, it solidifies by heating and drying.

[0060]

As described above, the EM according to the present invention is used.
According to the I countermeasure core, the following effects can be obtained.

(1) The first effect of the present invention is that the cable can be freely and easily mounted without being affected by the thickness or insertion space of the interface cable of the information processing device or the wire harness in the information processing device. In addition, the cross-sectional area and the width of the core can be easily increased or decreased according to the noise removal effect, cost, and the like.

Further, when the noise removing effect is not recognized, there is an effect that it can be easily removed and reused.

The reason is that, in the present invention, the EMI countermeasure core is usually clay-like. Due to the above effects, the EMI countermeasure core of the present invention can perform efficient noise countermeasures at the EMI test site.

(2) The second effect of the present invention is that
If the noise reduction effect is recognized with the MI countermeasure core attached, mass production can be applied.

The reason is that the EMI countermeasure core of the present invention has a feature of solidifying when irradiated with ultraviolet rays or heat.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a EMI countermeasure core according to a first embodiment of the present invention.

FIG. 2 is a plan view showing an appearance when the EMI countermeasure core is mounted in a bushing shape in the first embodiment of the present invention.

FIG. 3 is a view for explaining a solidification method of the core in the first embodiment of the EMI countermeasure core according to the present invention.

FIG. 4 is a perspective view showing the appearance of a second embodiment of an EMI countermeasure core according to the present invention.

FIG. 5 is a view for explaining a core solidification method in a second embodiment of the EMI countermeasure core according to the present invention.

FIG. 6 is a perspective view showing an appearance when a split core is used among conventional EMI countermeasure cores.

FIG. 7 is a cross-sectional view of a conventional EMI countermeasure core having an elastic material inside.

FIG. 8 is a perspective view showing an appearance when a tape-shaped core is used among conventional EMI countermeasure cores.

9A and 9B are views showing an appearance when a bushing with a ferrite core is used among conventional EMI countermeasure cores, wherein FIG. 9A is a perspective view, FIG. 9B is a side view of a nut side,
(C) is a sectional view taken along line AA of (b).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core 2 Cable 3 Housing 4 Housing opening 5 Ultraviolet irradiation device 6 Dryer 12 Elastic body 13 Tape 22 Bushing 24 Ferrite core 26 Sleeve 27 Collar 28 Bushing main body 30 Nut 31 Nut main body

Claims (3)

[Claims] 1. An insulating material which has clay-like elasticity and viscosity and which solidifies when irradiated with heat or ultraviolet rays, is mixed with a magnetic material having a high magnetic permeability and a high resistivity. An EMI countermeasure core characterized by the following. 2. The core according to claim 1, which is attached to an external interface cable of an information processing device, a wire harness inside the information processing device, and the like, and further irradiated with heat or ultraviolet rays to solidify the core. An EMI countermeasure core characterized by the following. 3. An EMI countermeasure core mounted on a cable, a wire harness, or the like, is an insulating member containing a high-permeability high-resistance magnetic material powder mixed therein, as long as it is not heated or irradiated with ultraviolet rays. , Add, tear, extend,
An EMI countermeasure core, wherein the core is made of a clay-like material that can be freely changed in shape including deformation and the like and detached from the cable or the like, and is solidified by heating or ultraviolet irradiation.