JPH01278095A - Magnetism-and-electromagnetism shielding body - Google Patents

Abstract

PURPOSE:To display the excellent electromagnetism-shielding performance and magnetism-shielding performance, to be lightweight, to be manufactured and worked easily and to be applied to a wide range by a method wherein a flake- shaped amorphous metal and a good conductive fiber are sandwiched between films in a random state. CONSTITUTION:An amorphous metal 2 is formed to be a flake (thin piece) shape; it is sandwiched between films 4 in a random state together with a conductive fiber 3; a magnetism- and electromagnetism-shielding body having both magnetism-shielding performance and electromagnetic-wave-shielding performance and having flexibility is constituted. Since the magnetism-shielding performance and electromagnetism-shielding performance are shouldered by mutually independent substances, an effect which is excellent in both the magnetism- shielding performance and electromagnetic-wave-shielding performance can be displayed. In addition, this magnetism- and electromagnetism-shielding body 1 formed to be a sheet shape is lightweight; works such as cut, bonding and the like can be effected; accordingly, it is applicable easily.

Description

[Detailed description of the invention] [Industrial application field] The present invention has excellent electromagnetic shielding ability and magnetic shielding ability,
Furthermore, the present invention relates to a magnetic/electromagnetic shield that is easy to manufacture, install, and adjust its shielding ability, and can be applied to any location.

[Conventional technology]

Electromagnetic waves generated by AC power lines and circuits, etc., or leakage magnetic flux from magnetic generating bodies, etc., can have a negative effect on precision electronic equipment, various measuring devices, and sometimes the human body, and if such effects are a problem. It is necessary to shield these electromagnetic waves or magnetism.

As is well known, in order to shield these, for example, if you want to shield electromagnetic waves, you can surround the electromagnetic wave generating body or equipment that dislikes the influence of electromagnetic waves with a good conductor.
Similarly, if magnetic fields are to be shielded, a magnetic material having high permeability may be used to surround a magnetic generating body or a device that is undesirable from the influence of magnetism.

For example, a magnetically shielded room is configured to form a sealed room that houses magnetism generators and equipment that dislikes magnetism, and to shield the room from magnetism by surrounding the entire room with highly magnetic materials such as pure iron plates. Alternatively, there is a coaxial shielded cable configured to block the influence of electric field changes (electromagnetic waves) by covering the core wire with a good conductor such as copper or aluminum via an insulator.

[Problem to be solved by the invention]

Incidentally, in recent years, as the development of superconducting technology has progressed rapidly, the magnetic environment in particular has been worsening.

As mentioned above, leakage magnetic flux from magnetic generators can have a major impact on precision electronic equipment and various measuring devices.
In particular, there is an increasing need to protect signal cables and the like from these magnetic influences. As mentioned above, signal cables are generally constructed to block the effects of electromagnetic waves by covering the core wire with a good conductor, but although copper and aluminum are good conductors, they are magnetic. Since it is not a material, it cannot cope with the magnetic environment and cannot be expected to have a magnetic shielding effect.

On the other hand, since the pure iron etc. that make up the magnetically shielded room can be both highly magnetic and a good conductor, it is possible to use it to shield both electromagnetic waves and magnetism. Even pure iron requires a considerable thickness to shield high magnetic fields, and if it is used as a structural element like the magnetically shielded room mentioned above, it is possible to take measures such as reinforcing the structure, but for example, It is difficult to apply this method to cables that require light weight, such as the above-mentioned cables.

The present invention has been made in view of the above circumstances, and is a magnetic/electromagnetic shield that can exhibit excellent electromagnetic shielding ability and magnetic shielding ability, is lightweight, easy to manufacture and install, and can be applied over a wide range of areas. The purpose is to provide the following.

[Means to solve the problem]

The magnetic/electromagnetic shield according to the present invention is formed into a flexible sheet by randomly sandwiching flaky amorphous metal and highly conductive fibers between films.

[Effect]

As is well known, amorphous metals exhibit extremely high magnetic permeability and are ideal as magnetic shielding materials. By forming this into a flake shape and sandwiching it between films in a random manner along with conductive fibers, a magnetic/electromagnetic shield that has both magnetic shielding ability and electromagnetic wave shielding ability and is flexible. is configured.

Since magnetic shielding and electromagnetic shielding are performed by independent substances, it is possible to exhibit excellent effects in both magnetic shielding ability and electromagnetic wave shielding ability. Furthermore, this magnetic/electromagnetic shield formed in a sheet shape is lightweight and can be processed by cutting, gluing, etc., so it is extremely easy to construct. In addition, a plurality of magnetic/electromagnetic shields can be stacked together by adhesion or the like.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are cross-sectional views showing an example of a magnetic/electromagnetic shielding body according to the present invention. This magnetic/electromagnetic shielding body 1 consists of a flaky amorphous metal 2 and a conductive fiber 3 arranged in a random pattern. It is formed into a sheet shape by sandwiching the film 4 in this state. Here, FIG. 2 shows amorphous metal 2 and conductive fiber 3 to help understand the structure.
is represented in a sparser state than the actual state.

As is well known, amorphous metal is an amorphous metal in which atoms are arranged irregularly without a regular lattice structure, and is produced by means such as rapid cooling of a melt, electrodeposition, vapor deposition, and sputtering. Due to their unique atomic structure, amorphous metals have various characteristics not found in conventional materials. Among them, iron-based alloys or cobalt-based alloys have high magnetic permeability and low coercivity that surpass those of permalloy. The magnetic permeability per unit weight is 5 to 8 times that of pure iron, making it optimal as a magnetic shielding material. Amorphous metal is usually supplied in the form of a ribbon with a speed of several tens of microns and a width of about 100+ am, and the amorphous metal 2 used in the present invention can be prepared by cutting the ribbon or by a known melt extraction method. However, it is desirable to apply the cavitation method (Japanese Unexamined Patent Publication No. 58-6907) which was previously invented and provided by the present applicant. In the cavitation method, molten metal is supplied to the surface of a roll that has a small leakage property and is rotating at high speed. After dividing the molten metal into fine molten metal droplets, Subsequently, the molten metal droplets are made to collide with a metal rotating body rotating at high speed to rapidly solidify them.

The conductive fiber 3 is made of a metal or the like having good conductivity and is formed into an extremely thin and arbitrary length. In this embodiment, the conductive fiber 3 is made of aluminum and has a diameter of about several μm to more than ten μm.

It is assumed that the length is approximately 1111 to several an.

The film 4 can be made of a synthetic resin such as acrylic resin, vinyl chloride, epoxy resin, or phenol resin, so that it has flexibility, weather resistance, and durability.

The magnetic/electromagnetic shield 1 may be obtained by uniformly dispersing the amorphous metal 2 and the conductive fibers 3 between the films 4 in the desired shape and fixing them with the film 4. A well-known paper machine may be used to lay the amorphous metal 2 and conductive fibers 3 on one of the films 4 in a uniform plane in a random state. In addition, as a fixing means, an adhesive, a hot melt method, or a vacuum packing method in which the amorphous metal 2 and the conductive fiber 3 are uniformly dispersed between two films 4 and then the films are brought into close contact by reducing the pressure between them. This can be done by any appropriate method.

The weight of the magnetic/electromagnetic shield in this embodiment is such that the amorphous metal 2 is 0.25 kg/s and the conductive fiber 3 is 0.01 to 0.1 Okg/s. , the total thickness of one sheet is approximately 0.
, 5 ml11.

According to the magnetic/electromagnetic shield 1 having the above structure, it is possible to exhibit both the magnetic shielding ability by the amorphous metal 2 and the electric field shielding ability by the conductive fiber 3 at a high level, and it is lightweight and flexible. Because of its richness, it can be applied to various things by taking advantage of its properties. The amount of amorphous metal 2 and conductive fiber 3 to be mixed is completely arbitrary as they do not interfere with each other, and by increasing the amount of amorphous metal 2 used, the magnetic shielding ability can be increased. The electromagnetic shielding ability can be increased by increasing the amount of . However, in these flaky amorphous metals 2 and conductive fibers 1 and 3, each piece of the amorphous metal 2 or each conductive fiber 3 is in contact with each other without being separated from each other. Needless to say, it is necessary to write the density to the extent that it becomes a state.

Furthermore, since the magnetic/electromagnetic shielding weight according to the present invention is formed in the form of a sheet with the film 4 forming the front and back sides, it can be cut and bonded, and a plurality of these sheet-like objects can be laminated. It can also be used as a layer, and by stacking layers, it is possible to increase the magnetic and electromagnetic wave shielding ability. In order to increase the magnetic/electromagnetic shielding ability, it is possible to increase the amount of amorphous metal 2 and the amount of conductive fiber 3 used to form two sheets, but it is possible to increase the amount of amorphous metal 2 and conductive fiber 3 used to form two sheets. Amorphous metal 2 layered between
If the conductive fibers 3 are layered quickly, not only will it be difficult to form them into a sheet shape, but flexibility will also be lost. It is preferable to use it.

FIG. 3 is a sectional view showing a cable constructed with the magnetic/electromagnetic shield 1 described above. The cable 6 has a conductor 7
, an insulator 8 covering the outside of the conductor 7, and an insulator 8
A magnetic/electromagnetic shield 1 is provided to further cover the magnetic field. In this case, the magnetic/electromagnetic shield 1 is coated on the insulator 8 by adhesion. However, covering by other means such as fusion is of course also a skill.

Now, assuming that the cable 6 is a large power cable, its operation will be explained.

When an alternating current flows through the conductor 7, electromagnetic waves (radio waves) are generated around the conductor 7. Naturally, the larger the current flowing, the stronger the electromagnetic waves become, and those with high power (large current) generate considerably strong electromagnetic waves.

In conventional concentric shielded cables in which the conductor 7 is surrounded by a conductor, the conductor can shield electromagnetic waves and block the influence of electromagnetic waves on the outside. It wasn't what I expected.

On the other hand, according to the cable 6, electromagnetic waves are transmitted to the film 4.
While being shielded by the conductive fibers 3 provided in between,
Magnetic flux is also shielded by the amorphous metal 2. In other words, an electric cable that eliminates the influence of both electromagnetic waves and magnetism is realized.

On the other hand, if this cable 6 is a signal cable, even if the cable 6 is placed in a strong magnetic field,
The magnetic flux is shielded by the magnetic/electromagnetic shield l and does not reach the conducting wire 7, so that no magnetic noise is picked up.

In this way, according to the cable 6 as described above, it is possible to realize an ideal cable that does not have the influence of magnetism and electromagnetic waves on the surrounding environment and reliably eliminates the influence of magnetism and electromagnetic waves from the surrounding environment. This makes it ideal for cables used in high magnetic and strong electric field environments, such as linear motors, superconducting devices, MHI (magnetic resonance imaging) devices, magnetic propulsion vessels, and magnetic refrigerators.

Further, FIG. 4 shows another example of the structure in which the magnetic/electromagnetic shield 1 of the present invention is similarly applied to a cable. This cable 6' is the cable 6 shown in FIG.
An insulating layer 9 is further formed on the outside of the magnetic/electromagnetic shield 1, which has an outer layer formed thereon.This protects the magnetic/electromagnetic shield I and makes it more durable. In this insulating layer 9, it is possible to arrange a conductor 7' whose influence on or from the surrounding environment can be ignored. Of course, it is also possible to further cover the outside of the insulating layer 9 with the magnetic/electromagnetic shielding body 1, and in that case, the influence of the magnetic and electromagnetic waves of the conductive wire 7' disposed within the insulating layer 9 is also eliminated. You will be able to do this.

Incidentally, as an application example of the magnetic/electromagnetic shield l according to the present invention, only the cables 6 and 6' are shown here, but it goes without saying that the present magnetic/electromagnetic shield l can be applied to such cables. The present invention is not limited to, but can be applied to any field that requires shielding of electromagnetic waves and magnetic fields.

For example, if a sealed space is surrounded by the present magnetic/electromagnetic shield l instead of an iron plate, a magnetically shielded room (electromagnetic shielded room) with higher performance than conventional ones can be easily constructed.

〔Effect of the invention〕

As explained above, the magnetic/electromagnetic shielding body according to the present invention not only can exhibit both magnetic shielding ability and electromagnetic shielding ability at a high level, but also is lightweight, highly flexible, By taking advantage of its characteristics of being cuttable and adhesive, it can be applied to all kinds of things that require magnetic and electromagnetic shielding. Furthermore, by adjusting the composition of the amorphous metal and conductive fibers or laminating the magnetic/electromagnetic shielding material, magnetic shielding ability or electric field shielding ability depending on the purpose can be easily obtained, and furthermore, it is easy to manufacture. It has excellent effects such as

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a magnetic/electromagnetic shield according to one embodiment. FIG. 2 is a partial plan view showing the magnetic/electromagnetic shield according to the same embodiment. 3 and 4 are both sectional views of a cable to which the magnetic/electromagnetic shield according to the present invention is applied. ! ...Magnetic/electromagnetic shielding body, 2...Amorphous metal, 3...Conductive fiber, 4.
·····film.

Claims (1)

[Claims] A magnetic/electromagnetic shield formed into a flexible sheet by randomly sandwiching flaky amorphous metal and highly conductive fibers between films.