JP5271143B2 - Magnetic shield body and rectangular tube body thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic shielding body which absorbs a manufacturing error and achieves good magnetic shielding performance, and also to provide a square cylindrical body thereof. <P>SOLUTION: The magnetic shielding body is provided with a plurality of cylindrical layers 13 and 14 of square hollow cylindrical shape formed of a magnetic body and mutually overlapped concentrically. The plurality of cylindrical layers 13 and 14 are configured by combining four magnetic members, each having an L-shaped cross-section perpendicular to the central axes of the cylindrical layers 13 and 14, into the square cylindrical shape. The mutually adjacent positions of the four magnetic members in any one cylindrical layer 13 out of two cylindrical layers 13 and 14, and the mutually adjacent positions of the four magnetic members in the other cylindrical layer 14 out of the two cylindrical layers 13 and 14, do not overlap mutually in the cross-sectional direction. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a magnetic shield body for shielding a magnetic field and a rectangular tube body used for the magnetic shield body.

  Conventionally, in order to shield a magnetic field, a magnetic shield room has been proposed in which a magnetic field generated by the magnetic field generation source is prevented from leaking outside by covering the magnetic field generation source. This magnetic shield room is put into practical use as a room (hereinafter referred to as “MRI room”) for installing an MRI (Magnetic Resonance Imaging) device used in a medical facility, for example. This magnetic shield room is generally configured by embedding magnetic materials in all or part of walls, ceilings, and floors. Magnetic flux that reaches these walls, ceilings, and floors is made of magnetic materials. By detouring through, the magnetic field is prevented from leaking outside.

  In such a magnetic shield room, the magnetic field generation source is surrounded by a wall, a ceiling, and a floor, so that the internal space of the magnetic shield room is sealed, and there is a possibility of giving a sense of pressure to the occupants. In order to eliminate this point, it has also been proposed to configure a magnetic shield room using an open type magnetic shield (see, for example, Patent Document 1). This open-type magnetic shield body is configured by supporting a plurality of cylinders with a frame body. According to this structure, since the inside and the outside of the magnetic shield room are visually opened through the internal space of the cylindrical body, it is possible to reduce the feeling of pressure on the person entering the room.

  However, since the magnetic shield body of Patent Document 1 has a plurality of cylinders in linear contact with each other, there is a problem that stress concentration occurs in the contact portion. In order to solve this problem, the inventors of the present application proposed a magnetic shield body configured by arranging a plurality of cylinders in a non-contact manner with a space between each other (see Patent Document 2). FIG. 10 is a plan view of a conventional magnetic shield room, and FIG. 11 is a perspective view of a conventional magnetic shield body. 10 and 11, the magnetic shield body 100 is configured by mounting a plurality of rectangular cylindrical tubes 103 having magnetic permeability in a plurality of through holes 102 formed in a frame 101. According to this structure, the stress load on the cylinder 103 can be reduced, and the magnetic shield body 100 can be easily assembled and disassembled.

  Furthermore, the inventors of the present application have also proposed to divide the cylinder into a plurality of parts and arrange the plurality of cylinders at intervals (see Patent Document 3; however, Patent Document 3 is the same as when the application was filed). Not yet published). According to this structure, by increasing the magnetic resistance along the axial direction of the plurality of cylinders, it is possible to promote the detour of the magnetic lines of force having the main direction along the axial direction in the adjacent direction of the plurality of cylinder units. It is possible to reduce or prevent magnetic field leakage in the axial direction.

JP-A-6-13781 JP 2008-160027 A Japanese Patent Application No. 2007-299548

  Here, considering the performance of the cylindrical body constituting the magnetic shield body alone, when the corner portion is formed in the cylindrical body, the magnetic characteristics at the corner portion change and the magnetic resistance increases. From the viewpoint of performance, it is preferable to use a spherical or cylindrical shape having no corners rather than a rectangular tube shape such as a rectangular parallelepiped shape or a cubic shape. In addition, the cylindrical shape is preferable because the cylindrical shape is easier to manufacture than the rectangular tube shape. However, considering the performance of the entire magnetic shield body when a plurality of cylindrical bodies are arranged side by side, when a plurality of cylindrical cylindrical bodies are arranged side by side, the gap between the cylindrical bodies increases, which is not preferable.

  For this reason, it is conceivable that the cylindrical body has a rectangular cylindrical shape to reduce the gap between the cylindrical bodies and to compensate for the change in the magnetic characteristics generated at the corner by some method. For example, two U-shaped members are arranged so as to face each other, and the butted portions are welded, and then the entire rectangular tube body is heat-treated in a heat treatment furnace, so that it is possible to correct deterioration of magnetic properties due to welding. . However, when joining by welding in this way, since the magnetic characteristics of this joined portion change due to heat, it is necessary to overlap the members at the joined portion to increase the thickness. When the thickness of the joint portion is increased in this way, as shown in FIG. 12 as a front view, the design of the end portion of the rectangular tube body is deteriorated, and the open type magnetic field in which the end portion is exposed to the room. It is not preferable in configuring the shield body. Furthermore, when manufacturing a square cylinder using a silicon steel plate having a thickness of about 0.35 mm to 0.7 mm, it is necessary to polymerize a plurality of cylindrical layers to obtain a desired magnetic resistance. When the cylindrical layers are polymerized, a gap is generated between the cylindrical layers at the joint portion having an increased thickness, which is not preferable because the magnetic resistance between the cylindrical layers is increased.

  Moreover, the magnetic shield body described in Patent Document 2 has difficulty in concrete production. That is, it is necessary to attach a rectangular tube body to the through hole of the frame member, and when a gap is generated between the frame member and the rectangular tube body, the magnetic shielding performance is reduced. It is preferable to match the outer dimension with the inner dimension of the frame member. However, in reality, manufacturing errors may occur in the frame member and the rectangular tube, and it is difficult to accommodate the rectangular tube in the frame member. In order to avoid such a problem, it is necessary to provide an adjustment margin for absorbing manufacturing errors. In order to provide this adjustment allowance, for example, the cylindrical layer constituting the rectangular tube body is divided into a plurality of members, the plurality of members are inserted into the frame member, and the plurality of members are mutually connected after the insertion. It is also conceivable to form a rectangular tube by connecting by welding or the like. However, when the magnetic bodies are bonded in this way, it is expected that the magnetization characteristics will change greatly and the magnetic resistance will increase at the bonded portion, so it is not preferable to simply divide the cylindrical layer.

  For this reason, as shown in FIG. 13 as a front view, it is also conceivable to provide an adjustment allowance between these flat plates by configuring each cylindrical layer by combining four flat plates. In this case, in order to reduce the magnetic resistance that detours in the adjacent direction of the plurality of cylindrical layers, it is conceivable to form a magnetic path by installing a corner angle material at the corner of each cylindrical layer. . However, in this structure, a gap corresponding to the plate thickness of the angle member is generated between the flat portions of each cylindrical layer, so when a plurality of cylindrical layers are superposed as shown in FIG. Is not preferable because the magnetic resistance between the cylindrical layers increases.

  Furthermore, in order to solve this problem, a structure as shown in FIG. 14 can be considered. In this structure, the point that each cylindrical layer is configured by combining four flat plates is the same as the structure of FIG. 13, but by concentrating the corner angle materials at the corners inside the cylindrical layer, It becomes possible to reduce the gap between the plane portions of the layers. However, since the thickness of the corner portion is increased by the corner angle material, the design of the end portion of the rectangular tube body is deteriorated, which is not preferable in configuring an open type magnetic shield body in which the end portion is exposed in the room. . Moreover, since the number of parts increases, there also exists a problem that an effort is required for the heat processing and construction of a square cylinder.

  Next, a structure as shown in FIG. In this structure, each cylindrical layer constituting the rectangular tube body is configured by combining two members having a substantially L-shaped cross section. In this structure, the design of the end portion of the rectangular tube body does not deteriorate, but the plate thickness of the corner portion where the magnetic resistance is originally large becomes half the plate thickness of the flat portion. In particular, when shielding a strong magnetic field such as the magnetic field of the MRI room, the magnetic saturation of the magnetic shield material must be taken into account, so if the permeability decreases due to the magnetic saturation of the rectangular tube, the adjacent direction of the rectangular tube As a result, the magnetic resistance detouring increases, and the shielding performance of the entire magnetic shield body decreases.

  The present invention has been made in view of such problems. 1) Magnetic permeability is reduced by reducing the magnetic resistance generated by the corners of the cylindrical layers and the gaps between the cylindrical layers constituting the rectangular cylindrical body. By avoiding the occurrence of magnetic saturation, which is a cause of deterioration, it is possible to obtain good magnetic shielding performance, 2) by making it possible to absorb manufacturing errors, reducing the number of parts and labor of construction, etc. An object of the present invention is to provide a magnetic shield body that can realize cost reduction and that can also have good end face design, and a rectangular tube body used for the magnetic shield body.

  In order to solve the above-described problems and achieve the object, the present invention according to claim 1 is a hollow rectangular tube-shaped cylindrical layer formed from a magnetic material, and is a plurality of layers that are polymerized concentrically with each other. 4 magnetic members each having at least two cylindrical layers of the plurality of cylindrical layers each having an L-shaped cross section in a cross section perpendicular to the central axis of the cylindrical layers. Are combined in a rectangular tube shape, and the adjacent positions of the four magnetic members in one of the two cylindrical layers and the other cylindrical shape of the two cylindrical layers The positions adjacent to each other of the four magnetic members in the layer were positions where they did not overlap each other in the direction of the cross section.

  According to a second aspect of the present invention, in the first aspect of the present invention, the adjacent positions of the four magnetic members in each of the plurality of cylindrical layers are different from each other adjacent to the respective cylindrical layers. Each of the plurality of cylindrical layers was configured such that the positions adjacent to each other of the four magnetic members in the cylindrical layer were not overlapped with each other in the direction of the cross section.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, at least one of the two cylindrical layers is an unequal side magnetic member in which the lengths of two sides in the cross section are different from each other. Thus, four unequal side magnetic members having the same shape are combined.

  According to a fourth aspect of the present invention, in the first aspect of the present invention according to the first or second aspect, at least one of the two cylindrical layers has two first equilateral sides having the same length of two sides in the cross section. A magnetic member and two second isosceles magnetic members having the same length in the cross section and different in length from the first equilateral magnetic member are alternately combined. did.

  According to a fifth aspect of the present invention, in the first aspect of the present invention according to any one of the first to fourth aspects, the innermost cylindrical layer disposed between the plurality of cylindrical layers is defined as 2 in the cross section. Four equal-sided magnetic members having the same length in one side and having the same shape are combined.

  The present invention according to claim 6 is the present invention according to any one of claims 1 to 5, wherein the magnetic member is made of a silicon steel plate.

  The present invention according to claim 7 is a magnetic shield body including a plurality of square tubes for the magnetic shield body according to any one of claims 1 to 6, wherein the plurality of square tubes and the plurality of square tubes are provided. And supporting means for supporting the plurality of rectangular tubes so that the plurality of rectangular tubes are arranged in parallel with each other at an interval. .

  According to the first or seventh aspect of the invention, since the magnetic body is configured by combining a plurality of magnetic members, the spacing between the plurality of magnetic members is determined by the manufacturing error of the support means and each magnetic member. Because it does not require angle materials, it eliminates the labor of construction at the corners and facilitates the production of the rectangular tube. Cost can be reduced. Further, it is possible to prevent only a part of the thickness from increasing or only the angle material from being exposed to the inner surface, thereby improving the design. In particular, among the at least two cylindrical layers of the plurality of cylindrical layers, the adjacent positions of the four magnetic members in any one of the cylindrical layers and the four magnetic members in the other cylindrical layer Since the positions adjacent to each other are not overlapped with each other, at least one layer of magnetic members can be arranged at any position of the rectangular tube body, and the adjacent positions are usually not positioned at corners where the magnetic resistance is large. Therefore, a magnetic saturation in the magnetic material is difficult to occur, and a local decrease in magnetic shielding performance due to a decrease in magnetic permeability due to the magnetic saturation can be reduced. In addition, since adjacent positions are not provided at corners where the magnetic resistance originally increases, it is possible to further contribute to a reduction in magnetic resistance.

  According to the second aspect of the present invention, the adjacent positions of the magnetic members in the cylindrical layer do not overlap with the adjacent positions of the four magnetic members in the other cylindrical layers adjacent to the cylindrical layer. In addition, since each of the plurality of cylindrical layers is configured, a magnetic saturation of the magnetic material is unlikely to occur at any adjacent position of the cylindrical layer, and the magnetic shielding performance is locally reduced due to a decrease in magnetic permeability due to the magnetic saturation. Reduction can be reduced.

  Since the present invention according to claim 3 is configured by combining four unequal-sided magnetic members having the same shape with each other, the magnetic member can be shared, and the management of the magnetic member and the rectangular tube body Since the manufacturing operation is facilitated, the manufacturing cost of the rectangular tube can be reduced, and at the same time, the rectangular tube can be easily constructed even if the number of layers is different.

  Since the present invention according to claim 4 is configured by combining four equilateral magnetic members having the same shape with each other, the magnetic member can be shared, and the management of the magnetic member and the manufacture of the rectangular tube body Since work becomes easy, the manufacturing cost of a square cylinder can be reduced. In particular, at least a part of the magnetic members can be made common to frames of different sizes, and the management of the magnetic members and the manufacturing work of the rectangular tube can be facilitated, so the manufacturing cost of the rectangular tube can be reduced.

  According to the fifth aspect of the present invention, the inner surface of the innermost rectangular tube that touches the user's eyes can be formed into a symmetrical shape along the adjacent lines of the magnetic member, thereby further improving the design. Can be achieved.

  According to the sixth aspect of the present invention, when the magnetic member is formed from a silicon steel plate, the material cost is lower than when the magnetic member is formed from permalloy or the like, so that the manufacturing cost of the rectangular tube can be reduced. .

1 is a perspective view of a magnetic shield body according to Embodiment 1 of the present invention. It is a front view of the rectangular tube body of FIG. It is a perspective view of the magnetic member which comprises the cylindrical layer of the square cylinder of FIG. 6 is a front view of a rectangular tube according to Embodiment 2. FIG. FIG. 10 is a front view of a rectangular tube according to a modification of the second embodiment. FIG. 6 is a front view of a rectangular tube body according to a third embodiment. It is a front view of the square cylinder used for experiment, (a) shows the conventional square cylinder made into the comparison object, (b) shows the square cylinder concerning this invention. It is a graph which shows the experimental result performed using the square cylinder of FIG. It is a figure which shows the front view of the square cylinder which concerns on an Example with the structure data of the magnetic member used for the said square cylinder. It is a top view of the conventional magnetic shield room. It is a perspective view of the conventional magnetic shield body. It is a front view of the square cylinder comprised by collating U-shaped member. It is a front view of the square cylinder body comprised combining 4 flat plates. It is a front view of the square tube body which concentrated and comprised the corner angle material inside the square tube body. It is a front view of the square cylinder formed by combining two members having a substantially L-shaped cross section.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. First, [I] the basic concept common to each embodiment was explained, then [II] the specific contents of each embodiment were explained, and [III] finally, a modification to each embodiment was explained. To do. However, the present invention is not limited to each embodiment.

[I] Basic concept common to the embodiments First, the basic concept common to the embodiments will be described. The magnetic shield body according to each embodiment is arranged around the magnetic field generation source, so that all or part of the magnetic field generated by the magnetic field generation source leaks to the outside through the magnetic shield body. This is to prevent this. The magnetic field generation source is arbitrary and includes an MRI apparatus, a permanent magnet, and an electromagnetic coil. The magnetic shield room is configured by arranging magnetic shield bodies on the walls, ceilings, or floors. However, in addition to the structure in which the magnetic shield bodies are arranged on the entire surface of these walls, only a part of these walls etc. Includes a structure for arranging a magnetic shield. However, since such an overall structure is the same as that of Patent Document 2 and Patent Document 3, the description thereof is omitted.

  Similar to Patent Document 2 and Patent Document 3, the magnetic shield body is configured by mounting a plurality of square cylinders having magnetic permeability in a plurality of through holes formed in a frame that is a support means. In such a configuration, one of the basic features of each embodiment is that each rectangular tube is composed of a hollow rectangular tube-shaped frame and a magnetic body arranged inside the frame, and the magnetic body Comprises a plurality of cylindrical layers polymerized concentrically with the frame. Each of the at least two cylindrical layers of the plurality of cylindrical layers is configured by combining four magnetic members having a L-shaped cross section in a cross section perpendicular to the central axis of the frame in a rectangular tube shape. The adjacent positions of the four magnetic members in any one of the two cylindrical layers and the adjacent positions of the four magnetic members in the other cylindrical layer of the two cylindrical layers In a position where they do not overlap each other in the direction of the cross section. Thus, regarding each cylindrical layer, a manufacturing error can be absorbed by comprising combining four magnetic members. Also, by setting the adjacent positions of the magnetic members of one cylindrical layer and the adjacent positions of the magnetic members of the other cylindrical layer to positions that do not overlap with each other, the magnetization characteristics are large at the adjacent positions. Even if it changes, the influence of the change can be reduced and good magnetic shielding performance can be obtained by arranging the portion where the change has occurred in different locations of one cylindrical layer and the other cylindrical layer. .

[II] Specific Contents of Each Embodiment Next, specific contents of each embodiment will be described.

[Embodiment 1]
First, specific contents of the magnetic shield body and the rectangular tube body according to the first embodiment will be described. 1 is a perspective view of a magnetic shield body according to the present embodiment (a part of the rectangular tube body is shown as an exploded perspective view), FIG. 2 is a front view of the rectangular tube body of FIG. 1, and FIG. It is a perspective view of the magnetic member which comprises the cylindrical layer of a cylinder. In the following, the distance in the Z direction in FIG. 1 is referred to as “height”, the distance in the Y direction is referred to as “width”, and the distance in the X direction is referred to as “depth”.

(Configuration-Magnetic shield and square tube)
As shown in FIG. 1, the magnetic shield body 1 is configured by supporting a plurality of rectangular tube bodies 10 with a frame 11. Each square cylinder 10 is configured to include a magnetic body 12 accommodated in a through hole inside the frame 11.

(Configuration-frame)
The frame 11 is a support means for supporting the rectangular tube body 10 and is formed in a hollow rectangular tube shape. Although FIG. 2 shows only a portion corresponding to one magnetic body 12 as the frame 11, in practice, a plurality of frames 11 are arranged side by side as shown in FIG. The plurality of frames 11 may be formed side by side after being formed separately, or may be formed integrally. For example, the frame 11 can be formed between the flat plates by arranging a plurality of flat plates in the horizontal direction and the vertical direction and combining them in a cross-beam shape. The material of the frame 11 is arbitrary as long as it has a sufficiently higher magnetic resistance than the magnetic body 12 and has a desired strength for supporting the magnetic body 12, and wood or resin can be used, for example. In particular, it is preferable to obtain an electromagnetic wave shielding effect by using a conductive material as the material of the frame 11.

  The cross-sectional shape of the frame 11 is arbitrary in a cross-section orthogonal to the central axis of the frame 11 (the Z-Y plane in FIG. 1 and the surface shown in FIG. 2; hereinafter, the same applies when referred to as “cross-section”). Here, the square cross section has the same height and width.

(Configuration-magnetic material)
The magnetic body 12 is disposed in a through hole formed inside the frame 11 and includes a first cylindrical layer (outer cylindrical layer) 13 and a second cylindrical layer (inner cylindrical layer) 14. The first cylindrical layer 13 is disposed concentrically with the frame 11 and is formed in a hollow rectangular tube shape having an outer dimension that substantially matches the inner dimension of the frame 11. The second cylindrical layer 14 is disposed concentrically with the frame 11 inside the first cylindrical layer 13 and has an outer dimension that substantially matches the inner dimension of the first cylindrical layer 13. It is formed in a hollow rectangular tube shape. In FIG. 2 and the subsequent drawings, there is a slight gap between the frame 11, the first cylindrical layer 13, and the second cylindrical layer 14 for convenience of illustration. These are arranged so as to be in close contact with each other.

(Configuration-Magnetic body-First cylindrical layer)
Here, as shown in FIG. 2, the first cylindrical layer 13 is configured by combining four magnetic members 13 </ b> A to 13 </ b> D into a rectangular tube shape. Each of these magnetic members 13 </ b> A to 13 </ b> D is an L-shaped member having an L-shaped cross section in a cross section orthogonal to the central axis of the frame 11, and is formed to have substantially the same depth as the frame 11. Here, the “L-shape” means a structure in which at least two plate-like members 13a and 13b are arranged in abutment with each other, as shown in FIG. The angle is not limited to a right angle, and includes, for example, an angle of less than 90 degrees, an angle of more than 90 degrees, or a rounded corner having an arbitrary curvature. Moreover, the length of the cross section of the two plate-like members 13a and 13b to be abutted includes not only the case where they are not equal to each other but also the case where they are equal to each other as in Embodiment 2 described later.

  However, the magnetic members 13A to 13D according to the present embodiment are formed so that the lengths of the sides in the cross sections of the two plate-like members 13a and 13b are L-shaped cross sections that are unequal to each other (hereinafter, A plate-like member having a relatively long cross section is referred to as “longitudinal member 13a”, and a plate-like member having a relatively short cross section is referred to as “short member 13b”). That is, as shown in FIG. 3, when the length of the side in the cross section of the longitudinal member 13a is L1, and the length of the side in the cross section of the short member 13b is L2, the magnetic members 13A to 13A are set so that L1> L2. 13D is formed. As described above, the magnetic members 13A to 13D in which the lengths of the two sides in the cross section are different from each other are referred to as “unequal-side magnetic members” as necessary.

  Here, although each magnetic member 13A-13D is arrange | positioned inside the said flame | frame 11 so that the longitudinal direction of the said magnetic members 13A-13D may follow the longitudinal direction of the flame | frame 11, each magnetic member 13A-13D is arrange | positioned. The arrangement directions in the frame 11 are different from each other. Specifically, as shown in FIG. 2, the longitudinal member 13a of the magnetic member 13A is the left side of the frame 11, the longitudinal member 13a of the magnetic member 13B is the top side of the frame 11, and the longitudinal member 13a of the magnetic member 13C is the right side of the frame 11. The longitudinal member 13a of the magnetic member 13D is disposed along the lower side of the frame 11, respectively.

  In such an orientation, each of the magnetic members 13A to 13D is affixed to the inner surface of the frame 11 by, for example, a double-sided adhesive sheet (not shown), or joined by welding or the like, and is attached to the inner surface of the frame 11. They are arranged in close contact so that the magnetic resistance generated when a gap is generated between them is made as small as possible. Thus, when each magnetic member 13A-13D is arrange | positioned, with respect to each inner surface of the flame | frame 11, the longitudinal member 13a of any one magnetic member 13A-13D and the other any one magnetic member 13A-13D of The short member 13b always comes into contact with the double-sided PSA sheet. Here, the inner dimension of one side of the frame 11 is F, and the length of the gap between the long member 13a of one of the magnetic members 13A to 13D adjacent to the short member 13b of the other magnetic member 13A to 13D is L3. Then, F = L1 + L2 + L3 (here, the thickness of the double-sided PSA sheet is ignored). The length L3 functions as an adjustment allowance for absorbing the manufacturing error of the frame 11 and the magnetic members 13A to 13D, and is determined in consideration of the manufacturing error of the inner dimension F and the lengths L1 and L2. . For example, the length L3 of the adjustment allowance is 1 mm or more. However, the length of the gap can be ideally zero, or after the magnetic members 13A to 13D are arranged inside the frame 11, the adjacent magnetic members 13A to 13D are directly or You may weld mutually etc. via the joint material which is not shown in figure.

  Each of the magnetic members 13A to 13D is made of a magnetic material, and has a magnetic permeability that can bypass the magnetic flux inside the magnetic members 13A to 13D. Although the specific kind of these magnetic members 13A-13D is arbitrary, a silicon steel plate (directional silicon steel plate, non-oriented silicon steel plate), a permalloy, an electromagnetic steel plate, or an amorphous plate can be used, for example. In particular, when the magnetic members 13 </ b> A to 13 </ b> D are formed from a silicon steel plate, the material cost is lower than when the magnetic members 13 </ b> A to 13 </ b> D are formed from permalloy or the like, and thus the manufacturing cost of the rectangular tube 10 can be reduced. More specifically, the magnetic members 13A to 13D can be manufactured by bending one silicon steel plate or joining two silicon steel plates to each other by welding or bonding. Preferably, the magnetic members 13 </ b> A to 13 </ b> D are formed by bending a single silicon steel plate, and the magnetic properties are initialized by annealing the bent portion. In addition, you may perform the coating for rust prevention etc. on each side surface of each magnetic member 13A-13D.

(Configuration-magnetic material-second cylindrical layer)
On the other hand, the second cylindrical layer 14 is configured by combining four magnetic members 14A to 14D in a rectangular tube shape, and each of the magnetic members 14A to 14D includes a long member 14a and a short member 14b. . However, since the structure, shape, arrangement method, and manufacturing method of each of the magnetic members 14A to 14D are the same as those of the magnetic members 13A to 13D of the first cylindrical layer 13, the description thereof is omitted. However, since the 2nd cylindrical layer 14 is arrange | positioned inside the 1st cylindrical layer 13, the cross-sectional dimension of each magnetic member 14A-14D of the 2nd cylindrical layer 14 is at least of the 1st cylindrical layer 13. The thickness of each magnetic member 13A to 13D is smaller than the cross-sectional dimension of each magnetic member 13A to 13D of the first tubular layer 13. Alternatively, magnetic members 13A to 13D and 14A to 14D having completely the same dimensions are used in the first cylindrical layer 13 and the second cylindrical layer 14, and the dimensions of the first cylindrical layer 13 and the second cylindrical layer 14 are the same. The difference may be absorbed by slightly increasing the mutual spacing of the magnetic members 13A to 13D in the first cylindrical layer 13 to be larger than the mutual spacing of the magnetic members 14A to 14D in the second cylindrical layer 14. Each of these magnetic members 14A to 14D is affixed to the inner surface of the first cylindrical layer 13 by, for example, a double-sided adhesive sheet (not shown) or joined by welding or the like. Are arranged in close contact with each other so that the magnetic resistance generated when a gap is generated between them is minimized.

(Configuration-Arrangement of first cylindrical layer and second cylindrical layer)
Here, as shown in FIG. 2, the adjacent positions of the four magnetic members 13 </ b> A to 13 </ b> D in the first cylindrical layer 13 and the adjacent positions of the four magnetic members 14 </ b> A to 14 </ b> D in the second cylindrical layer 14. Are positions that do not overlap each other in the cross-sectional direction (the direction from the axial center of the frame 11 to each side of the frame 11). For example, as shown in FIG. 2, the adjacent position P1 of the magnetic member 13A and the magnetic member 13B of the first cylindrical layer 13 and the adjacent position P2 of the magnetic member 14A and the magnetic member 14B of the second cylindrical layer 14 are: They are separated from each other by a distance L4 (where L4 ≠ 0). Specifically, such a structure is such that the short members 14b of the magnetic members 14A to 14D of the second cylindrical layer 14 are in contact with the long members 13a of the magnetic members 13A to 13D of the first cylindrical layer 13. In addition, the magnetic members 13A of the second cylindrical layer 14 are in contact with the short members 13b of the magnetic members 13A to 13D of the first cylindrical layer 13 so that the long members 14a of the second cylindrical layer 14 are in contact with each of the magnetic members 13A. It is achieved by determining the position and orientation of the arrangement of ˜13D, 14A-14D.

  According to such a structure, the magnetic shielding performance is lowered at positions adjacent to each other of the magnetic members 13A to 13D of the first cylindrical layer 13, and the magnetic members 14A to 14D of the second cylindrical layer 14 are mutually connected. Even if the magnetic shielding performance is lowered at the adjacent position, it is possible to avoid the portion where the magnetic shielding performance is lowered from overlapping, and further, at least the magnetic members 13A to 13D of the first cylindrical layer 13 or the second part are included in the portion. Since any one of the magnetic members 14 </ b> A to 14 </ b> D of the cylindrical layer 14 can be arranged in parallel to perform magnetic shielding, the degree of local decrease in the magnetic shielding performance in the magnetic body 12 can be reduced.

(Effect of Embodiment 1)
As described above, according to the first embodiment, since the magnetic body 12 is configured by combining the plurality of magnetic members 13A to 13D and 14A to 14D, the plurality of magnetic members 13A to 13D and 14A to 14D are mutually connected. The interval can be used as an adjustment allowance for absorbing the manufacturing error of the frame 11 and each of the magnetic members 13A to 13D and 14A to 14D, so that the rectangular tube body 10 can be easily manufactured.

  Further, since the four magnetic members 13A to 13D of the first cylindrical layer 13 and the four magnetic members 14A to 14D of the second cylindrical layer 14 have the same shape, the magnetic members 13A to 13D and 14A to 14D While commonality can be achieved, the management of the magnetic members 13A to 13D and 14A to 14D and the manufacturing work of the rectangular tube 10 are facilitated, so that the manufacturing cost of the rectangular tube 10 can be reduced.

  In addition, the mutually adjacent positions of the four magnetic members 13A to 13D in the first cylindrical layer 13 and the mutually adjacent positions of the four magnetic members 14A to 14D in the second cylindrical layer 14 are positions that do not overlap each other. Therefore, the degree of local deterioration of the magnetic shielding performance in the magnetic body 12 can be reduced.

  Furthermore, when the magnetic members 13A to 13D and 14A to 14D are formed from silicon steel plates, the material cost is lower than when the magnetic members 13A to 13D and 14A to 14D are formed from permalloy or the like. it can.

[Embodiment 2]
Next, a second embodiment will be described. This form is a form using an equilateral magnetic member in which the lengths of two sides in the cross section are the same. The configuration of the second embodiment is substantially the same as the configuration of the first embodiment unless otherwise specified, and the same configuration as that of the first embodiment is the same as that used in the first embodiment. The reference numerals and / or names are attached as necessary, and the description thereof is omitted (the same applies to the third and later embodiments described later).

  FIG. 4 is a front view of the rectangular tube according to the second embodiment. The magnetic shield body according to the second embodiment is configured by supporting a rectangular tube 20 with a frame 21. The frame 21 is configured similarly to the frame 11 of the first embodiment. The rectangular cylinder 20 includes a magnetic body 22, and the magnetic body 22 includes a first cylindrical layer 23 (outer cylinder) and a second cylindrical layer (inner cylinder) 24. The first cylindrical layer 23 is arranged concentrically with the frame 21 and is formed in a hollow rectangular tube shape having an outer dimension that substantially matches the inner dimension of the frame 21. The second cylindrical layer 24 is disposed concentrically with the frame 21 inside the first cylindrical layer 23, and has an outer dimension that substantially matches the inner dimension of the first cylindrical layer 23. It is formed in a hollow rectangular tube shape.

(Configuration-Magnetic body-First cylindrical layer)
Here, the first cylindrical layer 23 is configured by combining four magnetic members 23A to 23D into a rectangular tube shape. Each of these magnetic members 23 </ b> A to 23 </ b> D is an L-shaped member having an L-shaped cross section in a cross section orthogonal to the central axis of the frame 21, and is formed to have substantially the same depth as the frame 21. However, in the four magnetic members 23A to 23D according to the present embodiment, two of the magnetic members 23A and 23C have the same cross-sectional shape, and the other two magnetic members 23B and 23D are the same. The cross-sectional shape of the former two magnetic members 23A and 23C and the cross-sectional shape of the latter two magnetic members 23B and 23D are different from each other. Further, the lengths of the sides in the cross section of the two plate-like members 23a and 23b constituting the magnetic members 23A and 23C are equal to each other, and the two plate-like members 23c and 23d constituting the magnetic members 23B and 23D. The lengths of the sides in the cross section are equal to each other. Hereinafter, in the present embodiment, as necessary, magnetic members having the same length of two sides in a cross section are collectively referred to as an “equilateral magnetic member”, and the magnetic members 23A and 23C having a smaller cross-sectional shape are referred to as “equilateral magnetic members”. The “first equilateral magnetic members 23A and 23C” and the magnetic members 23B and 23D having a larger cross-sectional shape are referred to as “second equilateral magnetic members 23B and 23D”.

(Configuration-magnetic material-second cylindrical layer)
On the other hand, the second cylindrical layer 24 is configured by combining four magnetic members 24A to 24D into a rectangular tube shape. Two of the magnetic members 24A and 24C have the same cross-sectional shape, the other two magnetic members 24B and 24D have the same cross-sectional shape, and the former two magnetic members 24A, The cross-sectional shape of 24C and the cross-sectional shapes of the latter two magnetic members 24B and 24D are different from each other. Further, the lengths of the sides in the cross section of the two plate-like members 24a and 24b constituting each magnetic member 24A and 24C are equal to each other, and the two plate-like members 24c and 24d constituting each magnetic member 24B and 24D. The lengths of the sides in the cross section are equal to each other. Hereinafter, in the present embodiment, the magnetic members 24B and 24D having a smaller cross-sectional shape are referred to as “first equilateral magnetic members 24B and 24D” and the magnetic members 24A and 24C having a larger cross-sectional shape are They are referred to as isosceles magnetic members 24A and 24C ". Since the other structures, shapes, arrangement methods, and manufacturing methods of the magnetic members 24A to 24D are the same as those of the magnetic members 23A to 23D of the first cylindrical layer 23, description thereof is omitted. However, since the 2nd cylindrical layer 24 is arrange | positioned inside the 1st cylindrical layer 23, naturally the cross-sectional dimension of each magnetic member 24A-24D of the 2nd cylindrical layer 24 is at least 1st. By the thickness of each magnetic member 23A-23D of the cylindrical layer 23, it becomes smaller than the cross-sectional dimension of each magnetic member 23A-23D of the 1st cylindrical layer 23. Alternatively, the first cylindrical layer 23 and the second cylindrical layer 24 use magnetic members 23A to 23D and 24A to 24D having the same dimensions, and the dimensions of the first cylindrical layer 23 and the second cylindrical layer 24 are the same. The difference may be absorbed by slightly increasing the mutual distance between the magnetic members 23A to 23D in the first cylindrical layer 23 to be larger than the mutual distance between the magnetic members 24A to 24D in the second cylindrical layer 24.

(Configuration-Arrangement of first cylindrical layer and second cylindrical layer)
Here, as shown in FIG. 4, the adjacent positions P <b> 3 of the four magnetic members 23 </ b> A to 23 </ b> D in the first cylindrical layer 23 and the adjacent positions of the four magnetic members 24 </ b> A to 24 </ b> D in the second cylindrical layer 24. The position P4 is a position where they do not overlap each other in the direction of the cross section. Such a structure is such that the second equilateral magnetic members 24A, 24C of the second tubular layer 24 are in contact with the first equilateral magnetic members 23A, 23C of the first tubular layer 23, and the first tubular shape. The positions of the magnetic members 23A to 23D and 24A to 24D are arranged so that the first equilateral magnetic members 24B and 24D of the second cylindrical layer 24 are in contact with the second equilateral magnetic members 23B and 23D of the layer 23. This is achieved by determining the orientation.

(Configuration-Modification)
In particular, in the present embodiment, there is an advantage that at least a part of the magnetic members 23A to 23D and 24A to 24D can be used even when the overall size of the rectangular tube 20 changes. FIG. 5 is a front view of a rectangular tube body 25 according to a modification of the present embodiment. This rectangular tube 25 is obtained by increasing the height and width of the rectangular tube 20 of FIG. 4 by about 1.2 times, and includes a frame 26 and a magnetic body 27. The magnetic body 27 includes a first cylindrical layer (outer cylindrical layer) 28 and a second cylindrical layer (inner cylindrical layer) 29.

  Here, the first equilateral magnetic members 28A and 28C in the magnetic members 28A to 28D constituting the first tubular layer 28 are the same as the first equilateral magnetic members 23A and 23C of the first tubular layer 23 of FIG. The first equilateral magnetic members 29B and 29D in the magnetic members 29A to 29D constituting the second cylindrical layer 29 are the same as the first equilateral magnetic members 24B and 24D of the rectangular cylinder 24 in FIG. Only the second equilateral magnetic members 28B and 28D of the first cylindrical layer 28 and the second equilateral magnetic members 29A and 29C of the second tubular layer 29 are different from those in FIG. For example, the height and width of the rectangular tube 20 of FIG. 4 is 10 cm, the length of the side in the cross section of the first equilateral magnetic members 23A, 23C, 24B, 24D is 4 cm, and the second equilateral magnetic members 23B, 23D, 24A. The length of the side in the cross section of 24C is 6 cm. On the other hand, the height and width of the rectangular cylinder 25 in FIG. 5 is 12 cm, the length of the side in the cross section of the first equilateral magnetic members 28A, 28C, 29B, and 29D is 4 cm, the second equilateral magnetic member 28B, The length of the side in the cross section of 28D, 29A, and 29C is 8 cm. As described above, the first equilateral magnetic members 23A, 23C, 24B, 24D, 28A, 28C, 29B, and 29D are made common to the frames 21 and 26 having different sizes, and the second equilateral magnetic members 23B, The size can be adjusted by changing only the sizes of 23D, 24A, 24C, 28B, 28D, 29A, and 29C (however, conversely, the second equilateral magnetic members 23B, 23D, 24A, and 24C can be adjusted). , 28B, 28D, 29A, 29C may be used in common, and the dimensions may be adjusted by changing the sizes of the first equilateral magnetic members 23A, 23C, 24B, 24D, 28A, 28C, 29B, 29D).

(Effect of Embodiment 2)
As described above, according to the second embodiment, by forming the rectangular cylindrical bodies 20 and 25 using the equilateral magnetic members 23A to 23D, 24A to 24D, 28A to 28D, and 29A to 29D, the frames 21 having different sizes are formed. , 26, at least some of the magnetic members 23A, 23C, 24B, 24D, 28A, 28C, 29B, and 29D can be shared, so that these magnetic members 23A, 23C, 24B, 24D, 28A, 28C, 29B, The management of 29D and the manufacturing work of the rectangular cylinders 20 and 25 are facilitated, and the manufacturing cost of the rectangular cylinders 20 and 25 can be reduced.

[Embodiment 3]
Next, Embodiment 3 will be described. This form is a form in which the unequal side magnetic member and the equilateral magnetic member are alternately combined to form a square cylinder, and in particular, the second cylindrical layer is constituted by the equilateral magnetic member.

  FIG. 6 is a front view of a rectangular tube body according to the third embodiment. The magnetic shield body according to the third embodiment is configured by supporting a rectangular tube 30 with a frame 31. The frame 31 is configured similarly to the frame 11 of the first embodiment. The rectangular cylindrical body 30 includes a magnetic body 32, and the magnetic body 32 includes a first cylindrical layer (outer cylindrical layer) 33 and a second cylindrical layer (inner cylindrical layer) 34. The first cylindrical layer 33 is disposed concentrically with the frame 31 and is formed in a hollow rectangular tube shape having an outer dimension that substantially matches the inner dimension of the frame 31. The second cylindrical layer 34 is disposed concentrically with the frame 31 inside the first cylindrical layer 33 and has an outer dimension that substantially matches the inner dimension of the first cylindrical layer 33. It is formed in a hollow rectangular tube shape.

(Configuration-Magnetic body-First cylindrical layer)
Here, the first cylindrical layer 33 is configured by combining four magnetic members 33A to 33D in a rectangular tube shape. Each of these magnetic members 33A to 33D is configured similarly to the magnetic members 13A to 13D in the first cylindrical layer 13 of the first embodiment, and is configured as an unequal side magnetic member.

(Configuration-magnetic material-second cylindrical layer)
On the other hand, the second cylindrical layer 34 is configured by combining four magnetic members 34A to 34D in a rectangular tube shape. The lengths of the sides in the cross section of the two plate-like members 34 a and 34 b constituting the magnetic members 34 </ b> A to 34 </ b> D are equal to each other, and this length is about half the inner dimension of one side of the frame 31. Yes. Accordingly, the adjacent positions of the magnetic members 34 </ b> A to 34 </ b> D coincide with the substantially central position of each side of the frame 31.

(Configuration-Arrangement of first cylindrical layer and second cylindrical layer)
Here, as shown in FIG. 6, the adjacent positions P5 of the four magnetic members 33A to 33D in the first cylindrical layer 33 and the adjacent positions of the four magnetic members 34A to 34D in the second cylindrical layer 34. The position P6 is a position where they do not overlap each other in the direction of the cross section. In such a structure, since the first cylindrical layer 33 is configured by combining the magnetic members 33A to 33D which are unequal sides magnetic members, the adjacent positions of the magnetic members 33A to 33D are the respective positions of the frame 31. In contrast to the non-center position of the side, the adjacent positions of the magnetic members 34 </ b> A to 34 </ b> D of the second cylindrical layer 34 are achieved by matching the approximate center position of each side of the frame 31.

  Here, contrary to FIG. 6, the first cylindrical layer 33 may be constituted by four equilateral magnetic members and the second cylindrical layer 34 may be constituted by unequal magnetic members, but as shown in FIG. 6. By configuring as above, the adjacent positions P6 of the magnetic members 34A to 34D of the second cylindrical layer 34 can be matched with the center positions of the respective sides of the frame 31. Therefore, the inner surface of the second cylindrical layer 34 that can be seen by the user can be formed into a symmetrical shape along the adjacent lines of the magnetic members 34A to 34D, and the design can be improved. .

(Effect of Embodiment 3)
As described above, according to the third embodiment, the rectangular cylindrical body 30 is configured by alternately combining the unequal side magnetic members 33A to 33D and the equal side magnetic members 34A to 34D, and in particular, the second cylindrical layer 34 is mutually identical. By configuring with the equilateral magnetic members 34 </ b> A to 34 </ b> D having the cross-sectional shape, it is possible to improve the design of the inner surface of the second cylindrical layer 34 that touches the user's eyes.

〔Experimental result〕
Next, experimental results by the inventors will be described. FIG. 7 is a front view of a rectangular cylinder used in the experiment, in which (a) shows a conventional rectangular cylinder as a comparison object, and (b) shows a rectangular cylinder according to the present invention. As a conventional rectangular tube shown in FIG. 7A, a rectangular tube formed by abutting a pair of equilateral magnetic members at the corners and having a four-layer polymerization was used. As the rectangular tube according to the present invention shown in FIG. 7 (b), a rectangular tube made of four unequal-side magnetic members as shown in Embodiment 1 and having four layers is used. Here, with respect to each of the square tube body of FIG. 7A and the square tube body of FIG. 7B, the heat treatment is not performed after the formation of the corner portion, and the heat treatment is performed after the formation of the corner portion. The experiment was conducted using the following two types of rectangular cylinders. Each of the square cylinders was formed so that a cylindrical layer was formed using a directional silicon steel sheet having a thickness of about 0.35 mm, and the cross-sectional shape was about 150 mm and the length was 90 mm as a whole. Each square cylinder has an exciting coil wound around each of the four sides, applied with a magnetic field of 10 Hz, and a magnetic flux density B is measured by a B coil formed by winding the coil around any one side about 10 times. The curve of magnetic flux density B and magnetic field H was measured, and the relative permeability μr−magnetic flux density B was shown in the graph.

  This graph is shown in FIG. Further, in order to show the target performance, the graph of FIG. 8 shows the relative permeability μr−magnetic flux density B when the directional silicon steel sheet having a thickness of about 0.35 mm is used as it is. As is clear from FIG. 8, in the flat plate, the relative permeability μr increases from about 10,000 to about 60,000 without magnetic saturation until the magnetic flux density B increases from 0 to about 1.2 T. When the magnetic flux density B is further increased, the magnetic permeability μr gradually decreases due to magnetic saturation. As a manufacturer guarantee value of the magnetic shield body in the MRI room, it is generally required that the relative permeability μr is 10,000 or more when the magnetic flux density B is about 1.5T.

  On the other hand, in the case of using the rectangular tube of FIG. 7A, when the heat treatment is not performed, the magnetic flux density B is magnetically saturated at about 0.3 T and the heat treatment is performed. However, when the magnetic flux density B is approximately 0.7 T, the magnetic saturation is achieved, and at the magnetic flux density B higher than that, the relative permeability μr is drastically decreased, and the magnetic flux density, which is an action point as a magnetic shield body in the MRI room. When B = 1.5T, the relative magnetic permeability μr is almost 0, and the desired magnetic shielding performance cannot be obtained.

  On the other hand, when the rectangular tube of FIG. 7B is used, both the case where the heat treatment is not performed and the case where the heat treatment is performed are compared with the case where the square tube of FIG. 7A is used. Since the magnetic flux density B at which magnetic saturation occurs can be increased, and the magnetic flux density B = 1.5T, which is the point of action as a magnetic shield in the MRI room, the relative permeability μr = 10,000 can be secured. It was confirmed that the desired magnetic shielding performance can be obtained.

〔Example〕
Next, an example of a rectangular tube will be described. FIG. 9: is a figure which shows the front view of the square cylinder which concerns on an Example with the structure data of the magnetic member used for the said square cylinder. In this example, similarly to the third embodiment, a first cylindrical layer configured by combining four L-shaped unequal magnetic members and a second cylindrical layer configured by combining four equal-side magnetic members. Is an example in which However, the first cylindrical layer is not a single layer but is formed by polymerizing 12 cylindrical layers. The second cylindrical layer, the first cylindrical layer, and each layer of the first cylindrical layer were attached to each other with a double-sided tape. Hereinafter, the 12 cylindrical layers of the first cylindrical layer are referred to as 1 to 12 layers in order from the outside to the inside, and the second cylindrical layer is referred to as 13 layers. The outer dimension of the rectangular cylinder was 197 mm square. Triangular marks in the first cylindrical layer and the second cylindrical layer indicate the connection positions of the unequal side magnetic member and the equilateral magnetic member.

  In addition, on the right side of the figure, the dimensions of the odd-numbered magnetic members among the first to twelve layers constituting the first cylindrical layer are shown. For example, the outermost layer indicates that an unequal side magnetic member having a side of 80 mm and an unequal side magnetic member having a side of 105 mm are arranged with a gap of 12 mm. The dimensions of the even-numbered magnetic members in the first to twelfth layers constituting the first cylindrical layer are the upper and lower dimensions of the odd-numbered magnetic members shown on the right side of the figure (left and right with respect to the side along the horizontal direction). For example, in the two layers, an unequal side magnetic member having a side of 105 mm and an unequal side magnetic member having a side of 80 mm are arranged with a gap of 12 mm. Moreover, the dimension of the magnetic member which comprises a 2nd cylindrical layer is shown inside a square cylinder. Here, an equilateral magnetic member having a side of 92 mm is disposed with a gap of 4.6 mm.

  Furthermore, the right side of the figure shows the thickness when 1 to 12 layers are laminated (however, the thickness of the second cylindrical layer, which is 13 layers, and the thickness of the double-sided tape between each layer). For example, the thickness of 1-4 layers + 13 layers = 1.4 mm, the thickness of 1-8 layers + 13 layers = 2.8 mm, the thickness of 1-10 layers + 13 layers = 3.5 mm, 1-12 layers + 13 layers Thickness = 4.55 mm.

  Further, below these thicknesses, the number of the thinnest portions at each position is shown. For example, between the 4th layer and the 5th layer, since the connection positions of the unequal side magnetic member and the equal side magnetic member are not superposed on each other from the 1st layer to the 4th layer, the number of layers in the thinnest part is equal to the total number of layers. , The number of thinnest layers is four. Even between the 8th layer and the 9th layer, since the connection positions of the unequal side magnetic member and the equal side magnetic member do not overlap each other from the 1st layer to the 8th layer, the number of layers in the thinnest part is equal to the total number of layers. The number of laminated thin portions = 8. On the other hand, in the 9th layer, the connection position of the unequal side magnetic member is superposed on the connection position of the unequal side magnetic member in the 1st layer, and in the 10th layer, the connection position of the unequal side magnetic member is in the 2nd layer. Therefore, between the 10th layer and the 11th layer, the number of layers in the thinnest part is equal to the total number of layers minus 1, and the number of layers in the thinnest part = 9. Similarly, at the outer position of the 12 layers, the number of layers in the thinnest part is equal to the total number of layers minus 1, and the number of layers in the thinnest part is 11.

  Here, when it is known from experiments and calculations that the total number for obtaining the desired magnetic shielding performance is 10 layers, the structure as shown in FIG. 9 is adopted, and the thinnest layer is laminated at the outermost position. It can be seen that the number can be 11 (> 10), and the desired magnetic shielding performance can be secured. As described above, the number of stacked thinnest portions can be adjusted by the connection position of the unequal side magnetic member or the equal side magnetic member. Alternatively, by setting the connection position in the second cylindrical layer as a position that does not overlap with any of the connection positions in the first cylindrical layer, the number of layers of the thinnest portion in the outermost position is the layer of the second cylindrical layer It is possible to adjust the number of the thinnest layers by increasing the number (here, 1).

  The effect of the present invention is particularly noticeable when 10 layers or more layers are laminated as in the embodiment shown in FIG. 9, and when the angle material is arranged at the corner as in the prior art. Compared with the case where the angle material has about 10 layers and the magnetic shielding performance and designability are significantly reduced, the magnetic shielding performance and designability can be remarkably improved.

[III] Modifications to Each Embodiment While the embodiments of the present invention have been described above, the specific configuration and means of the present invention are within the scope of the technical idea of each invention described in the claims. It can be arbitrarily modified and improved within. Hereinafter, such a modification will be described.

(About problems to be solved and effects of the invention)
In addition, the problems to be solved by the invention and the effects of the invention are not limited to the above-described contents, and the present invention solves the problems not described above or has the effects not described above. There are also cases where only some of the described problems are solved or only some of the described effects are achieved.

(About shape and numerical values)
The shapes and numerical values shown in the above embodiments are examples, and each dimension value can be arbitrarily changed.

(Basic structure of rectangular tube)
Further, the present invention may be applied to a rectangular tube having a basic structure different from the above embodiments. For example, as in Patent Document 3 described above, the present invention is applied to a structure in which a rectangular tube is divided into a plurality of portions at a plurality of positions in the longitudinal direction, and the plurality of rectangular tubes are arranged at intervals. May be. That is, in each of the above embodiments, the case where the first cylindrical layer and the second cylindrical layer are longitudinal structures having the same length as the frame has been described. However, the first cylindrical layer and the second cylindrical layer are described. The layer may be divided at one or more locations in the longitudinal direction, and these divided bodies may be arranged at intervals.

(About multiple structures)
In each of the embodiments described above, the magnetic member is doubled by arranging the second cylindrical layer inside the first cylindrical layer, but the magnetic member is further arranged inside the second cylindrical layer. In addition, a magnetic member can be further arranged outside the first cylindrical layer, and a 13-layer structure as shown in the embodiment or a multiple structure with any other number of layers can be taken. Thus, when taking the multiple structure by a some cylindrical layer, the mutual adjacent position of the four magnetic members in each of a some cylindrical layer is in other cylindrical layers adjacent to the said each cylindrical layer. It is preferable to configure each of the plurality of cylindrical layers so that the positions adjacent to each other of the four magnetic members are not overlapped with each other in the cross-sectional direction. However, the adjacent positions are not necessarily allowed to be superposed. For example, in the case of adopting a 10-layer structure, the adjacent positions of the first to fifth layers do not overlap each other, and the adjacent positions of the sixth layer are Superimpose with the adjacent position of the first layer, superimpose the adjacent position of the seventh layer with the adjacent position of the second layer, and similarly, the adjacent positions of the eighth to tenth layers are adjacent to the third to fifth layers. Each position may be superposed, and even in this case, the adjacent positions adjacent to each other are not superposed, so that a magnetic detour path can be secured and magnetic saturation can be avoided. More preferably, since it is desirable that at least two layers of magnetic members are provided in any part of the rectangular tube, in this case, it is desirable to employ a multilayer structure of four or more layers.

(Assembly method of rectangular tube)
In each embodiment, the first cylindrical layer is affixed and fixed to the inside of the frame as the support means, and the second cylindrical layer is affixed to the inside of the first cylindrical layer and fixed. Thus, an example of assembling a rectangular tube was shown. However, in addition to assembling the rectangular cylinder using the frame as a support frame in this way, it is also possible to assemble the rectangular cylinder using a support frame prepared separately from the frame.

  For example, a support frame having a hollow rectangular tube-shaped through-hole is prepared, and a first cylindrical layer is attached and fixed to the inside thereof, and further a second cylindrical layer is formed inside the first cylindrical layer. A rectangular tube body can also be assembled by sticking and fixing. Similarly, in the case where the rectangular cylindrical body is composed of three or more layers, the cylindrical layer disposed on the innermost side from the cylindrical layer disposed on the outermost side among the plurality of cylindrical layers is similarly formed on the inner side of the support frame. The plurality of cylindrical layers may be fixed to each other or to the support frame while arranging the plurality of cylindrical layers in order.

  Alternatively, the second cylindrical layer is stuck and fixed to the outside of the support frame, and the first cylindrical layer is stuck and fixed to the outside of the second cylindrical layer, thereby fixing the rectangular tube body. It may be assembled. Similarly, in the case where the rectangular cylindrical body is composed of three or more layers, the cylindrical layer disposed on the outermost side from the cylindrical layer disposed on the innermost side among the plurality of cylindrical layers is similarly formed on the outer side of the support frame. The plurality of cylindrical layers may be fixed to each other or to the support frame while arranging the plurality of cylindrical layers in order.

  Further, a plurality of cylindrical layers may be sequentially arranged on both the inside and the outside of the support frame. In this case, the plurality of cylindrical layers can be more easily multilayered around the support frame.

  When the square cylinder is assembled using the support frame in this way, the square cylinder may be accommodated in the frame together with the support frame, or a plurality of cylindrical layers may be removed from the support frame to form a plurality of cylinders. Only the layer (that is, the rectangular tube) may be accommodated in the frame.

DESCRIPTION OF SYMBOLS 1,100 Magnetic shield body 10, 20, 25, 30 Rectangular cylinder 11, 21, 26, 31, 101 Frame 12, 22, 27, 32 Magnetic body 13, 23, 28, 33 1st cylindrical layer 13A-13D , 14A-14D, 33A-33D Magnetic member (unequal-sided magnetic member)
23A, 23C, 24B, 24D, 28A, 28C, 29B, 29D Magnetic member (first equilateral magnetic member)
23B, 23D, 24A, 24C, 28B, 28D, 29A, 29C Magnetic member (second equilateral magnetic member)
34A-34D Magnetic member (Equilateral magnetic member)
13a, 14a Plate member (longitudinal member)
13b, 14b Plate member (short member)
23a-23d, 24a-24d, 34a, 34b Plate member 14, 29, 34 Second cylindrical layer 102 Through-hole 103 Cylindrical layer P1-P6 Adjacent position

Claims (7)

A hollow rectangular tube-shaped cylindrical layer formed from a magnetic body, comprising a plurality of cylindrical layers polymerized concentrically with each other,
Each of at least two cylindrical layers of the plurality of cylindrical layers is formed by combining four magnetic members having a L-shaped cross-section in a cross section perpendicular to the central axis of the cylindrical layer into a rectangular tube shape. Configured,
The adjacent positions of the four magnetic members in one of the two cylindrical layers, and the mutual positions of the four magnetic members in the other cylindrical layer of the two cylindrical layers. Adjacent positions were positions where they did not overlap each other in the direction of the cross section
Square tube for magnetic shield. The adjacent positions of the four magnetic members in each of the plurality of cylindrical layers are relative to the adjacent positions of the four magnetic members in the other cylindrical layers adjacent to the respective cylindrical layers. , Each of the plurality of cylindrical layers is configured so as not to overlap each other in the direction of the cross section,
The square cylinder for magnetic shield bodies according to claim 1. At least one of the two cylindrical layers is an unequal side magnetic member in which the lengths of two sides in the cross section are different from each other, and configured by combining four unequal side magnetic members having the same shape.
The square cylinder for magnetic shield bodies according to claim 1 or 2. At least one of the two cylindrical layers is composed of two first equilateral magnetic members having the same length of two sides in the cross section and a member having the same length of the two sides in the cross section. The two first equilateral magnetic members having different side lengths from the first equilateral magnetic member were alternately combined.
The square cylinder for magnetic shield bodies according to claim 1 or 2. The cylindrical layers disposed on the innermost side among the plurality of cylindrical layers are equilateral magnetic members having the same length of two sides in the cross section and having the same shape. Composed of four
The rectangular tube body for magnetic shield bodies as described in any one of Claim 1 to 4. The magnetic member is composed of a silicon steel plate,
The square cylinder for magnetic shield bodies according to any one of claims 1 to 5. A magnetic shield body comprising a plurality of rectangular tubes for the magnetic shield body according to any one of claims 1 to 6,
The plurality of rectangular cylinders;
Support means for supporting the plurality of rectangular tubes so that end surfaces of the plurality of rectangular tubes are arranged in the same plane, and the plurality of rectangular tubes are arranged in parallel with each other at intervals. ,
Magnetic shield body comprising

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