JPH11274790A - Electromagnetic wave shielding door structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding door structure capable of shielding even electromagnetic waves at low frequencies, without providing a door stop projecting to obstruct a taking in-out of a sample at a floor part of a doorway. SOLUTION: Electromagnetic shield members 4, 5, 6, 7 respectively butted to a right and left vertical frames 1a, an upper frame 1b and a floor part (a) of a doorway 1 in the instant of closing a door 2 are mounted on a right and left stiles 2a, top and bottom rails 2b, 2c respectively of an electromagnetic wave shielding structure door 2 continuously around the door 2 such that the electromagnetic wave shielding members 4, 5 are mounted on the side faces of the right and left stiles 2a, and the top rail 2b continuously along their lengths and also at the joints of the stiles 2a and the top rail 2b and the electromagnetic wave shielding members 6, 7 are mounted on the lower face of the bottom rail 2c continuously along the length thereof, and these shielding members are made from a knitted or entwined mesh material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an electromagnetic wave shielding door which is attached to an entrance having a flat floor, and which can shield particularly low-frequency electromagnetic waves.

[0002]

2. Description of the Related Art Generally, doors having an electromagnetic wave shielding structure are installed at entrances and exits of an anechoic chamber or an electromagnetic wave shielding room, and particularly, around the shield door, electromagnetic waves are generated from gaps which are likely to be generated around the door when the door is closed. An electromagnetic wave shielding member is attached to prevent leakage.

Heretofore, this kind of electromagnetic wave shielding member has been attached to the door side, the entrance side, or both, and especially at the lower end of the door, for example, as shown in FIG. When the door 21 is closed,
A door stop 22 at which the lower end of the door abuts and protrudes is provided, and an electromagnetic wave shielding member 23 is attached to a contact portion between the door stop 22 and the door 21.

[0004]

However, the door stop 22 protrudes from the floor at a certain height so that the door 21 does not go too far when the door 21 is closed, so that the door stop 22 becomes an obstacle. There was a problem that the loading and unloading of the test specimen using a trolley etc. could not be performed smoothly.

Therefore, it is conceivable that the door stop 22 does not protrude from the floor surface. However, in a shield structure in which such a flat door stop (not shown) is formed, the shieldable magnetic field is 60 dB at 150 kHz. To the extent possible, it was extremely difficult to shield electromagnetic waves from low frequency magnetic fields (60 dB or more at 9 kHz).

At this time, it is conceivable that it is inevitable that a gap is linearly formed between the lower end of the door and the floor surface to form a leakage path for electromagnetic waves. Since it is not possible to form an electromagnetic wave shield with fingers or shield gaskets, it is necessary to make the door about four times thicker than the opening width of the doorway, which leads to an increase in the size and weight of the door and the opening and closing of the door. A functional problem has arisen, such as difficulty in performing the operation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In particular, it is possible to provide a low frequency electromagnetic wave without providing a protruding door stop which hinders the entrance and exit of a specimen at an entrance floor. An object of the present invention is to provide a structure of an electromagnetic wave shield door capable of reliably shielding.

[0008]

In order to solve the above problems, the structure of the electromagnetic wave shield door according to the first aspect of the present invention relates to a shield structure of an electromagnetic wave shield door which is attached to an entrance with a flat floor. At the same time, the door is closed around the electromagnetic wave shield door, and at the same time, the electromagnetic wave shield members respectively abutting around the entrance and the floor are continuously attached around the door.

According to a second aspect of the present invention, in the structure of the first aspect, the door is attached so that the door is simultaneously closed and lowered by a predetermined weight under its own weight, and is simultaneously opened and raised to the original position.

According to a third aspect of the present invention, in the structure of the first or second aspect, a plurality of electromagnetic shield members are attached in parallel around the door.

According to a fourth aspect of the present invention, in the structure of the first, second, or third aspect, the electromagnetic wave shielding member is formed of a mesh material knitted or knitted.

According to a fifth aspect of the present invention, there is provided an electromagnetic wave shielding door according to the first, second, third or fourth aspect, wherein the electromagnetic wave absorbing door is closed so that at least a gap between the door and the floor is closed. Attach the member to the door.

[0013]

1 to 4 show an embodiment of the present invention. In the drawings, for example, an electromagnetic wave shielding plate such as a galvanized steel plate is attached to an inner surface or an entire outer surface of a room. A door 2 having an electromagnetic wave shield structure, which is electromagnetically shielded by attaching an electromagnetic wave shield plate such as a galvanized steel plate to the surface, is attached to the entrance 1 of the anechoic chamber A.

A vertical frame 1a and an upper frame 1b made of a steel material such as a rectangular steel pipe are attached to the left and right sides and the upper end of the entrance 1, respectively. The floor part a of the entrance 1 is formed flat by, for example, continuously laying an electromagnetic wave shielding plate such as a galvanized steel sheet from the floor part of the anechoic chamber A.

The door 2 is rotated horizontally about the hanging base 2A side and freely opened and closed by opening and closing. When the door 2 is closed, it descends (sets down) by a predetermined amount by its own weight, and when it is opened, it is raised and lowered using a cylinder or a spring. It is mounted so as to rise (float) to the original position by the action of the mechanism 3.

At the same time as the door 2 is closed, the side surfaces of the left and right vertical frames 2a and the upper frame 2b of the door 2 are brought into contact with the side surfaces of the vertical frame 1a and the upper frame 1b of the entrance 1 via electromagnetic wave shielding members 4 and 5, respectively. The lower frame 2c is in contact with the electromagnetic wave shielding members 6 and 7.
And abuts on the floor portion a via the first portion.

In this case, since the door 2 closes and descends (sets down) by a predetermined amount by its own weight at the same time as the door 2 is closed, the electromagnetic wave shielding members 6 and 7 are crushed to some extent and can be reliably brought into contact with the floor portion a.

Further, when the door 2 is closed, the left and right vertical frames 2a and the upper frame 2b and the lower frame 2c have a space between the left and right vertical frames 2a and the left and right vertical frames 1a of the doorway 1, and the upper and lower frames 2b and 2b. Electromagnetic wave absorbing members 8 made of a ferrite plate or the like are attached so as to close gaps formed between the lower frame 1b and the lower frame 2c and the floor portion a, respectively.

In particular, the electromagnetic wave absorbing member 8 attached to the lower frame 2c is attached to both the inside (exit side) and the outside, and the external electromagnetic wave absorbing member 8 is connected to that of the left and right vertical frames 2a via the connecting portion 8a. doing.

The electromagnetic wave absorbing member 8 includes left and right vertical frames 2a,
It is attached to the inside of a holder 9 made of a galvanized steel plate or the like attached to each of the upper frame 2b and the lower frame 2c so as to be easily replaced.

The electromagnetic wave absorbing member 8 may be attached only to the lower frame 2c and not to the left and right vertical frames 2a and the upper frame 2b.

The electromagnetic wave shielding members 4 and 5 are provided on the side surfaces of the vertical frame 2a and the upper frame 2b, and the electromagnetic wave shielding members 6 and 7 are arranged on the lower frame 2a.
On the lower surface portion c, these members are continuous in the longitudinal direction, and in the electromagnetic wave shielding members 4 and 5, they are also continuously mounted on the connecting portion 2d between the left and right vertical frame 2a and the upper frame 2b. .

Further, the electromagnetic wave shielding member 5 is composed of the left and right vertical frames 2.
a and two side walls of the upper frame 2b are attached in parallel, and one electromagnetic wave shielding member 4 is attached between the electromagnetic wave shielding members 5, 5 along the electromagnetic wave shielding members 5, 5, respectively. .

Two electromagnetic wave shield members 7 are attached in parallel to the lower surface of the lower frame 2c, and one electromagnetic wave shield member 6 is attached between the electromagnetic wave shield members 7 along the electromagnetic wave shield member 7. ing. In addition, these electromagnetic wave shielding members can be appropriately increased according to the thickness of the door 2.

Further, the electromagnetic wave shielding members 4 and 5 are attached to the side grooves of the left and right vertical frames 2a and the upper frame 2b in the groove 10 formed continuously in the longitudinal direction of these members. And 7 are attached to a groove 10 formed continuously on the lower surface of the lower frame 2c in the longitudinal direction of the lower frame 2c.

Since the electromagnetic wave shielding members 4, 5, 6, 7 are attached in this manner, the electromagnetic wave shielding members can be easily replaced.

Further, these electromagnetic wave shielding members 4, 5, 6,
7 is made of an elastic rubber or the like having a high elastic modulus as a core, and the outside thereof is formed of a very conductive thin wire, for example, a large number of metal wires such as a thin copper wire. Is a mesh material formed by knitting a large number of metal wires, and the electromagnetic wave shielding members 5 and 7 are respectively formed by mesh materials formed by knitting a large number of metal wires. Note that all of the electromagnetic wave shielding members 4, 5, 6, 7 may be formed of a mesh material knitted in a mesh or knitted.

Since the electromagnetic wave shielding members 4, 5, 6, 7 are formed as described above, the electromagnetic wave shielding member can be made as thick as possible, and the shielding efficiency of the electromagnetic wave can be reduced. Can be significantly increased.

In general, the shielding efficiency of electromagnetic waves is proportional to the thickness and surface area of the shielding member (metal). Therefore, a mesh material knitted or knitted so as to have as many metal parts as possible is used as this type of electromagnetic wave shielding member. Are suitable.

In particular, the braided net has a larger number of metal wires and a larger amount of metal than the knitted braid, and therefore has a high shield shielding ratio for a low-frequency magnetic field.

The electromagnetic wave shielding characteristic is determined by the absorption loss and the reflection loss of the electromagnetic wave, and the absorption loss is proportional to the thickness of the electromagnetic wave shielding member. Therefore, the large number of metal wires of the electromagnetic wave shielding member increases the contact area on the surface of the electromagnetic wave shielding member, and thus the electromagnetic wave shielding member is more closely attached to the object (door frame and entrance / exit frame) with which the electromagnetic wave shielding member contacts, that is, the electric resistance. Decreases (conductivity increases), so that both absorption loss and reflection loss of electromagnetic waves increase.

In the propagation of an electromagnetic wave, reflection and absorption occur in a portion where the impedance of a propagating medium changes. Therefore, by laminating materials having different impedances such as an electromagnetic wave shielding member (metal), an electromagnetic wave absorbing member (ferrite absorber), and air, electromagnetic waves are shielded each time they pass through these members.

[0033]

The present invention has the above-described structure, and particularly, when the door is closed around the electromagnetic wave shielding door, a plurality of electromagnetic wave shielding members respectively contacting around the doorway and the floor portion are provided in parallel around the door. Since these electromagnetic wave shielding members are attached continuously and have many metal parts, and are formed of a mesh material knitted or mesh-knitted so as to have a very large contact area with a door and an entrance, the periphery of the door is formed. Can be reliably shielded even to low-frequency electromagnetic waves.

In particular, at the lower end of the door, an electromagnetic wave shield is provided so that the door is closed at the lower end of the lower frame and at the same time it comes into contact with the floor at the doorway, without providing a door stop projecting on the floor. It is only necessary to attach the member, and the door is closed so that it descends at the same time by its own weight by a predetermined amount, so the electromagnetic wave shielding member is crushed to some extent and it comes into contact with the floor part more securely and electrically The electromagnetic wave at the lower end of the door can be more reliably shielded.

Further, since there is no protruding door stop at the floor of the entrance, it is possible to smoothly carry out and carry in the specimen by using a cart or the like.

Further, since the electromagnetic wave absorbing member for closing the door around the door and closing the gap between the door, the entrance and the floor and the floor portion is continuously attached around the door, the electromagnetic wave shield around the door is closed. It can be performed more reliably.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an entrance and exit of an anechoic chamber having an electromagnetic wave shielding door of the present invention.

FIG. 2 is a longitudinal sectional view of an entrance having an electromagnetic wave shielding door of the present invention.

FIG. 3 is a partially enlarged view of an entrance having an electromagnetic wave shielding door of the present invention, in which (a) is a longitudinal sectional view showing an upper part of an entrance having an electromagnetic shielding door, and (b) is a longitudinal sectional view showing a lower part. It is.

FIG. 4 is a perspective view of the electromagnetic wave shield door of the present invention.

FIG. 5 is a longitudinal sectional view showing a lower part of an entrance having a conventional electromagnetic wave shielding door.

[Explanation of symbols]

 Reference Signs List A Anechoic chamber 1 Doorway 1a Left and right vertical frame 1b Upper frame 2 Door with electromagnetic shield structure 2a Left and right vertical frame 2b Upper frame 2c Lower frame 3 Lifting device 4 Electromagnetic wave shield member 5 Electromagnetic wave shield member 6 Electromagnetic wave shield member 7 Electromagnetic wave shield member 8 Electromagnetic wave absorption Member 8a Connecting part 9 Holder 10 Concave groove

Claims (5)

[Claims] 1. An electromagnetic wave shield door structure having a floor portion attached to a flat entrance, wherein the door is closed around the electromagnetic wave shield door, and at the same time, an electromagnetic wave shield member which comes into contact with the periphery of the entrance and the floor portion is provided on the door. The structure of the electromagnetic wave shielding door, which is continuously attached to the periphery. 2. The structure of the electromagnetic wave shielding door according to claim 1, wherein the door is mounted so as to descend by a predetermined amount while closing and to rise to an original position while opening. 3. The structure of the electromagnetic wave shielding door according to claim 1, wherein a plurality of electromagnetic wave shielding members are attached in parallel around the door. 4. The structure of the electromagnetic wave shielding door according to claim 1, wherein the electromagnetic wave shielding member is made of a knitted or net-meshed mesh material. 5. The electromagnetic wave absorbing member is attached to the door so as to close at least a gap between the door and a floor portion at the same time as closing the electromagnetic wave shielding door. The structure of the electromagnetic shield door.