KR20010028537A - Apparatus of Magnetic Field Shielding - Google Patents

Abstract

PURPOSE: An apparatus for shielding a magnetic field is provided to prevent magnetic filed energy from being entered or escaped toward and away from a specific space. CONSTITUTION: An apparatus for shielding a magnetic field has a magnetic field shielding part(40) for bypassing the magnetic filed entering in a specific space and for absorbing the magnetic filed escaping from the specific space. The magnetic filed shielding part is made of an alloy of Fe, Co, Cu, and Ni, so that the magnetic filed has a high transmissivity. The magnetic field shielding part is formed as hollow type. The empty center portion of the hollow typed magnetic field shielding part is not affected by the magnetic filed, and the magnetic flux of the magnetic filed is concentrated in the rest of the hollow typed magnetic field shielding part. Therefore, the shielding effect of the magnetic filed is achieved. The apparatus for shielding the magnetic field is wound along a winding direction(30) of a potential transformer and an axial direction(20) of core.

Description

Magnetic shielding device {Apparatus of Magnetic Field Shielding}

The present invention relates to a magnetic shield device that prevents magnetic energy from entering a certain space and leaking to the outside.

In general, shielding means shielding electron energy from entering a predetermined space or leaking to the outside. This principle is applied to reduce noise applied from the outside. An example of this is a transformer. A transformer is a device that receives AC power from one circuit and supplies power to another circuit by electromagnetic induction. At this time, even if noise is included in the primary side of the transformer, the signal from which the noise is removed is output to the secondary side. That is, the shielding by the noise is made in the transformer.

Referring to FIG. 1, a conventional transformer includes a core 10 generating electromotive force by an electromagnetic induction phenomenon, a first coil wound around the core 10 by a first winding number n1, and a core 10. ) Is provided with a second coil wound by the second winding number n2. The first voltage V1 is applied to the first coil wound around the core 10 to form a primary side, and the second voltage V2 is output to the second coil wound around the core 10 to form a secondary side. . At this time, the relationship between the number of turns, the voltage ratio, the current ratio is shown in equation (1).

Where a is the number of turns, n1 is the number of turns of the first coil, n2 is the number of turns of the second coil, V1 is the primary voltage, V2 is the secondary voltage, I1 is the primary current, and I2 is the secondary current. Each means.

On the other hand, a shield case is provided around the coil wound around the core 10 of the transformer to cover what needs to be shielded from the influence of an external electric field in a coil part or the like. The shield case is mainly composed of a metal container to shield the electric field formed perpendicular to the current. On the other hand, the shield case can shield the electric field, but there is a difficulty in shielding the magnetic field. Accordingly, noise caused by a magnetic field is included to cause distortion of the signal, and there is a problem of causing electromagnetic interference (hereinafter referred to as "EMI").

Accordingly, an object of the present invention is to provide a magnetic shield device that prevents magnetic energy from entering a certain space and leaking to the outside.

1 is a diagram illustrating a configuration of a transformer.

2 is a view showing a magnetic shield device of the present invention.

<Description of the code | symbol about the principal part of drawing>

10,20: core 30: winding

40: shield part

In order to achieve the above object, the magnetic field shielding apparatus of the present invention includes magnetic field shielding means for bypassing a magnetic field entering an arbitrary space and absorbing a magnetic field emitted to the outside.

Other objects and features of the present invention other than the above object will become apparent from the description of the embodiments with reference to the accompanying drawings.

Referring to Figure 2 will be described a preferred embodiment of the present invention.

Referring to FIG. 2, the magnetic shield device of the present invention includes a magnetic shield portion 40 for bypassing a magnetic field entering an arbitrary space and absorbing a magnetic field emitted to the outside.

In the magnetic field shield portion 40 of the present invention, the middle region of the material having a high permeability is formed into an empty space so that the magnetic flux is focused on the material of the magnetic field shield portion, and the magnetic field is not affected by the magnetic field in the middle region. In other words, the magnetic field shielding becomes possible. The effect of this magnetic field shielding is shown in Table 1.

Magnetic field blocking rate 30 cm 30 cm left Right 30 cm Top 30 cm Rear 30 cm Power off 0 0 0 0 0 Power on 9.5 mG 40mG 50mG 27mG 0.8mG Magnetic shield part 1.12mG 1.73mG 2.73mG 1.2mG 0mG Block rate () 89 96 97 91 91

To this end, the magnetic shield portion 40 is made of an alloy of iron (Fe), cobalt (Co), copper (Cu) and nickel (Ni) has a high permeability (μ). Permeability μ satisfies the condition of Equation 2.

Here, B means magnetic flux density and H means magnetic field strength. That is, the magnetic permeability mu is proportional to the magnetic flux density B and inversely proportional to the strength H of the magnetic field. In this case, the magnetic shield part material of the present invention is configured to have a high magnetic flux density, and thus has a high permeability μ.

On the other hand, when the magnetic shield device of the present invention is applied to a transformer, not only the electric field is shielded by the magnetic field shield portion made of a metal material, but also the magnetic field can be shielded by the high permeability of the metal material. In this case, it is preferable to mount the magnetic field shielding device in the winding 30 direction and the core 20 direction of the transformer. In addition, the magnetic field shield may be of a built-in type that is mounted inside the chassis (not shown) of the transformer according to the designer's intention, or may be configured of an external type installed outside. In addition, the magnetic shield device of the present invention will be applicable to other fields that need to shield the magnetic field according to the designer's intention.

As described above, the magnetic field shielding apparatus of the present invention has an advantage of not only reducing noise caused by the magnetic field but also minimizing the influence of EMI.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (4)

And a magnetic shield means for bypassing a magnetic field entering an arbitrary space and absorbing a magnetic field emitted to the outside. The method of claim 1, The magnetic field shielding device has a high magnetic permeability and a central area of the magnetic field shielding means. The method of claim 1, Magnetic field shielding device, characterized in that the material of the magnetic shield means is an alloy of iron, cobalt, copper and nickel. The method of claim 1, And the magnetic field shielding means is used as a shield case of a transformer.