JP5626769B2 - Magnetic shield body - Google Patents

Description

  The present invention relates to a magnetic shield body for shielding a magnetic field.

  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. 54 is a plan view of a conventional magnetic shield room, and FIG. 55 is a perspective view of a conventional magnetic shield body (a part of the magnetic square tube body is shown as an exploded perspective view). 54 and 55, the magnetic shield body 100 is for shielding magnetism leaking from the MRI room, and a plurality of square tubes having magnetic permeability in a plurality of through holes 102 formed in the frame 101. A cylindrical body (magnetic body rectangular cylinder) 103 is mounted. According to this structure, the stress load on the magnetic body rectangular tube 103 can be reduced, and the magnetic shield body 100 can be easily assembled and disassembled.

JP-A-6-13781 JP 2008-160027 A

  However, in order to maintain the desired magnetic shield performance, the magnetic shield body of Patent Document 2 needs to have a depth dimension that is longer than the width dimension of each magnetic body square tube. There is a problem that the field of view is blocked by the square tube, and the feeling of pressure on the room occupant cannot be sufficiently reduced.

  This problem is shown in more detail. 56 is a longitudinal sectional view of the analysis model of the magnetic shield body 100, and FIG. 57 is an elevation view of this analysis model. Here, considering the symmetry of the magnetic shield body 100, only the ¼ region is shown. Represents. FIG. 58 is a perspective view of an analysis model of the magnetic body rectangular tube 103 used in the magnetic shield body 100. As a magnetic field generation source, an MRI electromagnet coil (magnetomotive force = 40000 AT) was assumed, and it was assumed that the magnetic shield body 100 was installed at a location 2000 mm away from the magnetic field generation source. The magnetic body rectangular tube 103 has a height = width = 296 mm, a depth = 300 mm, a thickness = 7 mm, an interval between adjacent magnetic body rectangular tubes 103 = 2 mm, and a relative permeability of the magnetic body rectangular tube 103 in the x direction. The relative permeability μx = 10000, the relative permeability μy = 10000 along the y direction, and the relative permeability μz = 1000 along the z direction. The evaluation surface of the leakage magnetic field was set at a position opposite to the magnetic field generation source across the magnetic shield body 100 and at a position 300 mm from the side surface of the magnetic shield body 100.

  The leakage magnetic flux density on the evaluation surface when a magnetic field generated from a magnetic field generation source was applied to such an analysis model was obtained by three-dimensional magnetic field analysis. The result is shown in FIG. In FIG. 59, as the leakage magnetic flux density in each region of the magnetic shield body 100 increases, the color becomes darker (the same applies to the other drawings illustrating the leakage magnetic flux density). Of this evaluation surface, the maximum magnetic flux density in the central region (the region of height = width = 2400 mm) in the x direction and the y direction was 8.24E-5 (T).

  Next, the results of analysis performed using other analysis models will be described. FIG. 60 is a front view of an analysis model of the magnetic shield body 200. Here, considering the symmetry of the magnetic shield body 200, only the quarter region is shown. In this analysis model, in order to further reduce the feeling of pressure on the occupants, it is assumed that a magnetic body rectangular tube 201 having a large opening is provided in the central region (height = width = 2400 mm) in the x and y directions. . That is, only the magnetic rectangular tube 201 arranged in the central region is configured with height = width = 2400 mm, and the magnetic rectangular tube 202 arranged in other regions is similar to the analysis model of FIG. It was assumed that height = width = 300 mm. Other conditions were the same as in FIG.

  The leakage magnetic flux density on the evaluation surface when a magnetic field generated from a magnetic field generation source was applied to such an analysis model was obtained by three-dimensional magnetic field analysis. The result is shown in FIG. The magnetic flux density distribution on this evaluation surface is different from the magnetic flux density distribution of the analysis model of FIG. 57, and the maximum magnetic flux density of the large-aperture magnetic rectangular tube 201 in the central region is 12.91E-5 (T). This is a significant increase over the 57 analysis models. This is presumably because the magnetic shielding tube 201 having a significantly increased height and width has a significantly reduced magnetic shielding performance compared to the magnetic member rectangular tube 202 whose height and width are not increased.

  As is clear from these analysis results, in order to further reduce the feeling of pressure on the occupants, when some of the magnetic rectangular tubes are simply opened, if the magnetic rectangular tubes are not opened large Compared with this, the magnetic shielding performance is greatly reduced.

  The present invention has been made in view of such problems, and by providing a large opening, it is possible to further reduce the feeling of pressure on a room occupant and to obtain the required magnetic shielding performance. An object of the present invention is to provide a magnetic shield body.

In order to solve the above-described problems and achieve the object, the magnetic shield body according to claim 1 is a magnetic shield body including a plurality of magnetic cylinders arranged in parallel with each other through a support means. From the application region to which the strongest magnetism from the magnetism generation source is applied among the regions in the magnetic shield body and including a part of the plurality of magnetic cylinders, the magnetism Magnetization is induced in a region to be reduced in the region of the shield body where the magnetic leakage to the outside is to be reduced and other than the region to be reduced including the other part of the plurality of magnetic cylinders. This reduces the leakage magnetism from the reduction target area to the outside, or is an application area to which the strongest magnetism is applied from the magnetic source among the areas in the magnetic shield body, and the plurality of magnetic cylinders Body axis A region to be reduced from which the magnetic leakage to the outside is reduced in the region of the magnetic shield body from the application region including a part of the magnetic plate-like member arranged non-parallel to the direction. A magnetic guiding path is provided that reduces magnetic leakage to the outside from the reduction target region by guiding magnetism to a region other than the reduction target region including a part of the magnetic cylinder of the magnetic cylinder , The relative magnetic permeability of a part of the magnetic cylinders in the magnetic cylinder, and the relative permeability along the z direction which is the cylinder axis direction of the magnetic cylinder, or along the direction perpendicular to the z direction. The magnetic induction path is formed by setting at least one of the relative magnetic permeability different from the relative magnetic permeability in the same direction in the other magnetic cylinder among the plurality of magnetic cylinders, In the magnetic cylinder, only a part of the outer periphery of the magnetic cylinder is cut out. A notch formed at the side and corners of the magnetic cylinder, and the relative permeability along the direction perpendicular to the notch is determined by the notch. This is a notch for reducing the relative magnetic permeability in the same direction in a magnetic rectangular tube having the same shape with no part, and is a notch formed with a length and a width corresponding to a required reduction amount of the relative permeability. The relative permeability of the magnetic cylinder was adjusted by providing a portion.

The magnetic shield body according to claim 2 is the magnetic shield body according to claim 1 , wherein the magnetic cylinder is a square rectangular magnetic square cylinder, and the relative permeability of the part of the magnetic cylinders. Among these, the relative permeability along the z direction, the relative permeability along the x direction that is orthogonal to the z direction and orthogonal to one side surface of the magnetic cylinder, or the z direction and the x The magnetic induction path is formed by setting at least one of the relative permeability along the y direction orthogonal to the direction to be different from the relative permeability along the same direction in the other magnetic cylinder. did.

The magnetic shield body according to claim 3 is the magnetic shield body according to claim 1 or 2 , wherein the magnetic cylinder body arranged in the shortest area on the shortest path from the application area to the reduction target area. The magnetic induction path was formed in a region other than the shortest region by making the relative permeability smaller than the relative permeability of other magnetic cylinders.

The magnetic shield body according to claim 4 is the magnetic shield body according to any one of claims 1 to 3 , wherein the relative permeability along the z direction of the magnetic cylinder included in the reduction target region. In contrast, the magnetic induction path is formed in a region other than the surrounding region by reducing the relative permeability along the same direction in the other magnetic cylinders arranged in the surrounding region around the reduction target region. did.

The magnetic shield body according to claim 5 is the magnetic shield body according to any one of claims 1 to 4 , wherein the relative permeability along the z direction of the magnetic cylindrical body included in the reduction target region. On the other hand, by increasing the relative permeability along the same direction in other magnetic cylinders included in the opposite region located on the opposite side of the application region across the reduction target region, the opposite region The magnetic induction path was formed.

A magnetic shield body according to claim 6 is the magnetic shield body according to any one of claims 1 to 5 , wherein a part of the plurality of magnetic cylinders is replaced with another magnetic cylinder. It was formed as a large opening magnetic cylinder having an opening larger than the body, and the reduction target area was an area including the large opening magnetic cylinder.

According to a seventh aspect of the present invention , in the magnetic shield body according to any one of the first to sixth aspects, the support means is formed of a conductive material.

According to the magnetic shield body according to claim 1, magnetic leakage to the outside in the region of the magnetic shield body from the application region to which the strongest magnetism is applied from the magnetic source in the region of the magnetic shield body. By providing a magnetic guide path that reduces the leakage magnetism from the reduction target area to the outside by guiding the magnetism to areas other than the reduction target area where it is desired to reduce the magnetism, the magnetism incident on the magnetic shield body from the magnetic source is Since the magnetic field can be guided to a region other than the reduction target region via the magnetic guide path and the magnetism transmitted to the reduction target region can be reduced, the magnetism leaking from the reduction target region can be reduced. Therefore, even when a large opening is provided in the reduction target area, the magnetism leaking from the large opening can be reduced, and by providing the large opening, the feeling of pressure on the occupant can be reduced, and at the same time, the required magnetism Shielding performance can be ensured.
Further, the relative permeability of a part of the plurality of magnetic cylinders, the relative permeability along the z direction that is the cylinder axis direction of the magnetic cylinder, or orthogonal to the z direction. A magnetic induction path is formed by setting at least one of the relative magnetic permeability along the direction to be different from the relative magnetic permeability in the same direction in the other magnetic cylinders in the plurality of magnetic cylinders. Therefore, it is possible to adjust the relative permeability in a desired direction according to the positional relationship between the application region and the reduction target region, and it is possible to reduce magnetism leaking from the reduction target region in various magnetic shield bodies.
In addition, a notch formed by notching only a part of the outer peripheral portion of the magnetic cylinder to the magnetic cylinder, the notch formed at the side surface and the corner of the magnetic cylinder There is a notch portion for reducing the relative permeability along the direction perpendicular to the notch portion from the relative permeability in the same direction in the magnetic rectangular cylinder of the same shape without the notch portion, Since the relative permeability of the magnetic cylinder was adjusted by providing a notch formed with a length and width corresponding to the required reduction in relative permeability, the required direction (vertical direction, horizontal direction, and The relative permeability in one or more directions selected from the three directions in the depth direction) can be reduced by the required reduction amount, and the relative permeability in each direction for each magnetic rectangular tube can be easily adjusted. can do. In particular, since the relative permeability can be adjusted by forming a notch, the mutual spacing of the magnetic square cylinders, the shape and thickness other than the notch can be made constant, and the manufacture and management of the magnetic square cylinder No increase in labor is required, the assembly of the magnetic shield body is easy, and the design of the magnetic shield body is not lowered. For example, in the magnetic shield body of the MRI room, even if the direction and angle of the magnetic field change with the replacement of the MRI, the height, width, and depth of each magnetic square tube body are the same. The support means can be dealt with by replacing the magnetic rectangular cylinders that differ only in the notch portions.

According to the magnetic shield body according to claim 2 , the magnetic cylinder is a square cylinder-shaped magnetic square cylinder, and among the relative permeability of some of the magnetic cylinders, the relative permeability along the z direction. The relative permeability along the x direction perpendicular to the z direction and perpendicular to one side of the magnetic cylinder, or the relative permeability along the y direction perpendicular to the z direction and the x direction. In the case where the magnetic cylinder is formed as a magnetic rectangular cylinder because at least one of the other magnetic cylinders has a relative permeability different from the relative permeability along the same direction, the magnetic induction path is formed. In addition, it is possible to adjust the relative permeability in a desired direction according to the positional relationship between the application region and the reduction target region, and it is possible to reduce magnetism leaking from the reduction target region in various magnetic shield bodies.

According to the magnetic shield body according to claim 3 , the relative permeability of the magnetic cylinder disposed in the shortest area on the shortest path from the application area to the reduction target area is set to the relative permeability of the other magnetic cylinder. Since the magnetic guiding path is formed in a region other than the shortest region by making it smaller, the magnetism induced in the shortest route from the application region to the reduction target region can be reduced, and the magnetism induced in the reduction target region can be reduced. Can be reduced.

According to the magnetic shield body of the fourth aspect , with respect to the relative magnetic permeability along the z direction of the magnetic cylinder included in the reduction target region, other magnetic elements arranged in the peripheral region around the reduction target region By reducing the relative permeability along the same direction in the cylindrical body, a magnetic guiding path is formed in a region other than the surrounding region, so that magnetism leaking from the surrounding region to the outside of the magnetic shield body along the z direction can be prevented. It is possible to reduce the magnetism that leaks from the reduction target region along the z direction.

According to the magnetic shield body of the fifth aspect , the relative permeability along the z direction of the magnetic cylinder included in the reduction target region is located on the opposite side to the application region with the reduction target region interposed therebetween. Since the magnetic induction path is formed in the opposite region by increasing the relative permeability along the same direction in the other magnetic cylinders included in the opposite region, the magnetic shield body of the magnetic shield body extends along the z direction from the opposite region. Increasing the magnetism leaking to the outside can reduce magnetism leaking from the reduction target area along the z direction.

According to the magnetic shield body according to claim 6 , a part of the plurality of magnetic cylinders is formed as a large opening magnetic cylinder having an opening larger than that of the other magnetic cylinders, Since the reduction target region is a region including the large opening magnetic cylinder, the magnetism incident on the magnetic shield body from the magnetic source can be guided to a region other than the large opening magnetic cylinder through the magnetic guide path, Since the magnetism transmitted to the large opening magnetic cylinder can be reduced, the magnetism leaking from the large opening magnetic cylinder can be reduced. Therefore, even when a large opening magnetic cylinder is provided, the magnetism leaking from the large opening magnetic cylinder can be reduced, and by providing the large opening magnetic cylinder, it is possible to reduce the feeling of pressure on the occupant. At the same time, the required magnetic shielding performance can be ensured.

According to the magnetic shield body of the seventh aspect , since the supporting means is formed of a conductive material, an electromagnetic wave shielding effect can be obtained, and even when the magnetism from the magnetic source fluctuates, the fluctuation occurs. Magnetism can be reduced by the effect of eddy currents.

It is an elevation view of the magnetic shield body according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of a main part of the magnetic rectangular tube shown in FIG. It is explanatory drawing for demonstrating notionally a magnetic guiding path. It is a perspective view of an actual magnetic square cylinder. It is a perspective view of a homogenization model. It is a perspective view of the magnetic square cylinder in which the relative magnetic permeability μx was adjusted. It is a figure which shows the calculation result with respect to the model of FIG. It is a perspective view of the magnetic square cylinder in which the relative magnetic permeability μy was adjusted. It is a figure which shows the calculation result with respect to the model of FIG. It is a perspective view of the magnetic square cylinder in which the relative magnetic permeability μz was adjusted. It is a figure which shows the calculation result with respect to the model of FIG. FIG. 5 is a perspective view of a magnetic rectangular tube whose relative magnetic permeability μy and μz are adjusted. It is a figure which shows the calculation result with respect to the model of FIG. It is a figure regarding the magnetic square cylinder in which the notch part is not formed. It is a figure regarding the magnetic square cylinder in which the notch part was formed. It is a figure regarding the magnetic square cylinder at the time of cutting all without leaving the connection length Wy. It is a perspective view of the magnetic square cylinder in which the relative magnetic permeability μx was adjusted. It is a figure which shows the calculation result with respect to the model of FIG. It is a perspective view of the magnetic square cylinder in which the relative magnetic permeability μy was adjusted. It is a figure which shows the calculation result with respect to the model of FIG. FIG. 5 is a perspective view of a magnetic rectangular tube with adjusted relative magnetic permeability μx and μy. It is a figure which shows the calculation result with respect to the model of FIG. It is a perspective view of the magnetic square cylinder in which the relative magnetic permeability μz was adjusted. It is a figure which shows the calculation result with respect to the model of FIG. It is an elevational view of a magnetic shield body without a large opening. It is an elevation view of a magnetic shield body provided with a large opening. It is a longitudinal cross-sectional view common to the magnetic shield body of FIG. It is a perspective view of the analysis model of the magnetic shield body of FIG. It is a perspective view of the analysis model of the magnetic shield body of FIG. FIG. 27 is a perspective view of a magnetic prism that constitutes the magnetic shield body of FIGS. 25 and 26. It is a figure which shows the three-dimensional magnetic field analysis result when not forming a magnetic induction path. It is a figure which shows the three-dimensional magnetic field analysis result at the time of forming a magnetic induction path. It is a figure which shows the magnitude | size and direction of magnetic flux distribution when not forming a magnetic induction path. It is a figure which shows the magnitude | size and direction of magnetic flux distribution at the time of forming a magnetic induction path. It is a figure which shows the three-dimensional magnetic field analysis result when not forming a magnetic induction path. It is a figure which shows the three-dimensional magnetic field analysis result at the time of forming a magnetic induction path. It is a figure which shows the magnitude | size and direction of magnetic flux distribution when not forming a magnetic induction path. It is a figure which shows the magnitude | size and direction of magnetic flux distribution at the time of forming a magnetic induction path. FIG. 26 is a perspective view of an analysis model of a magnetic shield body similar to FIG. 25. It is a figure which shows the three-dimensional magnetic field analysis result when not forming a magnetic induction path. It is a figure which shows the three-dimensional magnetic field analysis result at the time of forming a magnetic induction path. 6 is an elevation view of a magnetic shield body according to Embodiment 2. FIG. It is explanatory drawing for demonstrating notionally a magnetic guiding path. It is an elevation view of a magnetic shield body. It is a perspective view of the analysis model of the magnetic shield body of FIG. It is a perspective view of the magnetic body square tube which comprises the magnetic shield body of FIG. It is a perspective view of a homogenization model. It is a figure which shows the three-dimensional magnetic field analysis result when not forming a magnetic induction path. It is a figure which shows the three-dimensional magnetic field analysis result at the time of forming a magnetic induction path. It is a figure which shows the magnitude | size and direction of magnetic flux distribution when not forming a magnetic induction path. It is a figure which shows the magnitude | size and direction of magnetic flux distribution at the time of forming a magnetic induction path. 6 is an elevation view of a magnetic shield body according to Embodiment 3. FIG. It is explanatory drawing for demonstrating notionally a magnetic guiding path. 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 longitudinal cross-sectional view of the analysis model of a magnetic shield body. It is an elevation view of an analysis model. It is a perspective view of the analysis model of the magnetic body square tube used for the magnetic shield body. It is a figure which shows a three-dimensional magnetic field analysis result. It is a front view of the analysis model of a magnetic shield body. It is a figure which shows a three-dimensional magnetic field analysis result.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. However, the present invention is not limited to each embodiment.

[Embodiment 1]
First, the magnetic shield body according to the first embodiment will be described. In this form, a large opening is formed in the central region of the magnetic shield body.

(Constitution)
First, the basic configuration of the magnetic shield body will be described. FIG. 1 is an elevation view of a magnetic shield body according to the present embodiment, and FIG. 2 is a perspective view of a main part of the magnetic rectangular tube body of FIG. 1 (a part of the magnetic rectangular tube body is shown as an exploded perspective view). In the following, the distance in the Z direction in FIGS. 1 and 2 is referred to as “depth”, the distance in the X direction is referred to as “width”, and the distance in the Y direction is referred to as “height”. As shown in FIGS. 1 and 2, the magnetic shield body 1 is configured by a frame 10 that supports a plurality of magnetic rectangular cylinders 20 so as to be spaced from each other.

  The magnetic shield body 1 is arranged around a magnetic field generation source (not shown), so that all or a part of the magnetic field generated by the magnetic field generation source is exposed to the outside via the magnetic shield body 1. This is to prevent leakage. The magnetic field generation source is arbitrary and includes an MRI apparatus, a permanent magnet, an electromagnetic coil, and a superconducting magnet. The magnetic shield room is configured by arranging the magnetic shield body 1 on its wall, ceiling, or floor, but in addition to the structure in which the magnetic shield body 1 is arranged on the entire surface of these walls, etc., part of these walls and the like. The structure which arrange | positions the magnetic shield body 1 only in this is included. However, parts that are not particularly described can be configured in the same manner as in Patent Document 2.

  The frame 10 is a support means for supporting the magnetic rectangular tube body 20 and is formed in a hollow rectangular tube shape. The plurality of frames 10 may be formed side by side after being formed separately, or may be formed integrally. For example, the frame 10 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. A through hole 11 is formed inside the frame 10, and the magnetic rectangular tube 20 can be accommodated in the through hole 11.

  The material of the frame 10 is arbitrary as long as the magnetic resistance is sufficiently larger than that of the magnetic body 12 and has a desired strength for supporting the magnetic rectangular cylinder 20. For example, wood or resin is used. it can. In particular, by using a conductive material as the material of the frame 10, it is possible to obtain an electromagnetic wave shielding effect, and even when the magnetism from the magnetism source varies due to movement of the magnetism source, etc. Magnetism can be reduced by the effect of eddy currents. The vertical cross-sectional shape of the frame 10 in the vertical cross-section perpendicular to the central axis of the frame 10 (ZY plane in FIG. 2, hereinafter the same in the case of simply “vertical cross-section”) is arbitrary. It has a square shape with the same width and width.

  The magnetic rectangular cylinder 20 is disposed in a through hole 11 formed inside the frame 10 and is formed in a hollow rectangular cylinder shape having an outer dimension substantially matching the inner dimension of the frame 10. The magnetic rectangular tube 20 is disposed between adjacent magnetic rectangular tubes 20 with a space corresponding to the thickness of the frame 10. The magnetic rectangular cylinder 20 is made of a magnetic material. Although the specific kind of this magnetic material 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 rectangular tube 20 is formed from a silicon steel plate, the material cost is lower than when the magnetic rectangular tube 20 is formed from permalloy or the like, so that the manufacturing cost of the magnetic rectangular tube 20 can be reduced. For example, the magnetic rectangular tube 20 is manufactured by bending one silicon steel plate or joining two silicon steel plates to each other by welding or bonding. When the magnetic rectangular tube 20 is formed by bending one silicon steel plate, it is preferable to initialize the magnetization characteristics by annealing the bent portion. In addition, you may perform the coating for rust prevention etc. on each side surface of the magnetic square cylinder 20. FIG.

  Here, as the plurality of magnetic rectangular cylinders 20, more specifically, a magnetic rectangular cylinder 20A and a magnetic rectangular cylinder 20B are arranged. The magnetic square cylinder 20A is formed with the same height and width as the conventional one, and the magnetic square cylinder 20B is a large opening cylinder formed with a larger height and width than the magnetic square cylinder 20A. It is. However, when it is not necessary to distinguish between them, they are simply referred to as a magnetic rectangular tube 20.

  Here, among the plurality of magnetic square cylinders 20, some of the magnetic square cylinders 20 are formed with notches 30 to 32. The notches 30 to 32 are formed to adjust the relative magnetic permeability of the magnetic rectangular tube 20, and the side portion 21 along the x direction and the side along the y direction of the magnetic rectangular tube 20. In at least one (all in FIG. 2) of the right-angled corners 23 formed by the part 22 or the side part 21 along the x direction and the side part 22 along the y direction, It is formed as a notch. However, the shape of the notches 30 to 32 is not limited to the slit shape, and may be a hole shape such as a round hole shape or an elliptic hole shape. In addition, as long as a magnetic discontinuous space can be formed by excluding a part of the side portions 21 and 22 and the corner portion 23 of the magnetic rectangular tube body 20, the notch portions 30 to 32 having an arbitrary shape are formed. can do.

  Thus, by forming the notches 30 to 32 in a part of the plurality of magnetic rectangular cylinders 20 constituting the magnetic shield body 1 and adjusting the relative permeability thereof, A difference in relative magnetic permeability can be provided inside the magnetic shield body 1, and a magnetic guiding path 40 described later can be formed. That is, the region for forming the notches 30 to 32, the portion for forming the notches 30 to 32, the width of the notches 30 to 32 (when the notches 30 to 32 are slit-shaped, Dimension in a direction perpendicular to the forming direction) and the length of the cutout portions 30 to 32 (when the cutout portions 30 to 32 are slit-shaped, the direction along the formation direction of the cutout portions 30 to 32) The relative magnetic permeability can be reduced by a required reduction amount, and the magnetic guiding path 40 can be provided in the required path. Hereinafter, the significance of forming the notches 30 to 32 in this way will be described in more detail. In addition, since the relative permeability is decomposed in three directions of the x direction, the y direction, and the z direction, in the following, the relative permeability in the x direction is μx, the relative permeability in the y direction is μy, and the relative permeability in the z direction. The magnetic susceptibility is referred to as μz.

(Configuration-magnetic taxiway)
The magnetic shield body 1 configured as described above includes a magnetic guiding path 40. FIG. 3 is an explanatory diagram for conceptually explaining the magnetic guiding path 40, and here, only the ¼ region is shown in consideration of the symmetry of the magnetic shield body 1. This magnetic guiding path 40 reduces the leakage magnetism from the reduction target region E2 to the outside by guiding magnetism from the application region E1 to a region other than the reduction target region E2.

  The application region E1 is a region to which the strongest magnetism from the magnetic source is applied among the regions in the magnetic shield body 1. For example, the application region E1 is a region located at the shortest distance from the magnetic source, but is not limited to a region located at the shortest distance. Here, the upper and lower and left and right central regions (the leftmost lowermost region in FIG. 3) of the magnetic shield body 1 in FIG. 1 are defined as application regions E1.

  Further, the reduction target area E2 is an area in the magnetic shield body 1 where it is desired to reduce magnetic leakage to the outside. For example, when the evaluation point for evaluating leakage magnetism from the magnetic shield body 1 is set on the side opposite to the magnetic source with the magnetic shield body 1 interposed therebetween, the evaluation point is an area located at the shortest distance from this evaluation point. is there. Here, the region corresponding to the large opening magnetic rectangular cylinder 20B is set as a reduction target region E2.

  In FIG. 3, in order to induce magnetism from the application region E1 to regions other than the reduction target region E2, a plurality of magnetic guide paths 40 indicated by arrows are provided. Each of the plurality of magnetic induction paths 40 is a path that exits from the application area E1 and reaches another area while avoiding the reduction target area E2. By providing such a magnetic guide path 40, the magnetism incident on the magnetic shield 1 from the magnetic source is guided from the application region E1 to a region other than the reduction target region E2, and the magnetism reaching the reduction target region E2 is reduced. Therefore, the magnetism leaking from the reduction target area E2 is reduced, and the magnetism leaking at the evaluation point is reduced.

  Such a method of specifying the formation position of the magnetic guiding path 40 is generally to increase the relative permeability of the magnetic rectangular tube 20 arranged in the region corresponding to each magnetic guiding path 40 (magnetic resistance). Or reducing the relative permeability of the magnetic rectangular tube 20 disposed in a region other than the region corresponding to each magnetic guiding path 40 (increasing the magnetic resistance). By determining the relative relationship of the relative permeability of each magnetic rectangular tube 20 of the magnetic shield body 1 by such a method, the magnetic rectangular tube 20 determined so as to increase the relative permeability is connected. The path becomes the magnetic guiding path 40.

  More specifically, the method for specifying the formation position of the magnetic guide path 40 will be described as the following first to third methods. These first to third methods are mutually independent methods, and the formation position of the magnetic guiding path 40 may be specified by any one method. However, the formation position specified by each of the first to third methods does not prevent the formation of overlapping positions.

  In the first method, the relative magnetic permeability of the magnetic rectangular tube 20 arranged in the shortest region E3 on the shortest path from the application region E1 to the reduction target region E2 is changed to the relative magnetic permeability of the other magnetic rectangular tube 20. In this method, the magnetic guiding path 40 is formed in a region other than the shortest region E3 by making it smaller. That is, in the shortest region E3 of FIG. 3, the relative permeability of the magnetic rectangular tube 20 is set to be smaller than the relative permeability of the other magnetic rectangular tube 20, and thus, the region other than the shortest region E3. A magnetic guiding path 40 is formed on the surface. By forming the magnetic guiding path 40 in this way, it is possible to reduce the magnetism guided to the shortest path from the application area E1 to the reduction target area E2, and to reduce the magnetism induced to the reduction target area E2. . In other words, in the first method, the relative permeability of the magnetic rectangular tube 20 arranged in the avoidance region on the path from the application region E1 to the region other than the reduction target region E2 without passing through the reduction target region E2. It can be said that the magnetic induction path 40 is formed in the avoidance region by making the magnetic permeability larger than the relative magnetic permeability of the other magnetic rectangular tube 20.

  Further, in the second method, with respect to the relative magnetic permeability along the z direction of the magnetic rectangular tube 20 included in the reduction target region E2, another magnetic element arranged in the peripheral region E4 around the reduction target region E2 is used. In this method, the magnetic induction path 40 is formed in the surrounding region E4 by increasing the relative permeability along the same direction in the rectangular tube body 20. That is, in the peripheral region E4 of FIG. 3, the relative permeability μz along the z direction of the magnetic rectangular tube 20 is equal to the relative permeability μz along the z direction of the magnetic rectangular tube 20 included in the reduction target region E2. The magnetic guide path 40 is formed in a region other than the surrounding region E4. By forming the magnetic guiding path 40 in a region other than the surrounding region E4 as described above, the magnetism leaking from the surrounding region E4 to the outside of the magnetic shield body 1 along the z direction can be reduced, and the reduction target region E2 can be reduced in the z direction. It is possible to reduce magnetism that leaks along.

  In the third method, the relative magnetic permeability along the z direction of the magnetic rectangular tube 20 included in the reduction target region E2 is located on the opposite side of the application region E1 with the reduction target region E2 interposed therebetween. In this method, the magnetic induction path 40 is formed in the opposite region E5 by increasing the relative permeability along the same direction in the other magnetic rectangular tube 20 included in the opposite region E5. That is, in the opposite region E5 of FIG. 3, the relative permeability μz along the z direction of the magnetic rectangular tube 20 is equal to the relative permeability μz along the z direction of the magnetic rectangular tube 20 included in the reduction target region E2. The magnetic induction path 40 is formed in the opposite area E5. By forming the magnetic guide path 40 in this way, increasing the magnetism leaking from the opposite area E5 to the outside of the magnetic shield body 1 along the z direction leaks from the reduction target area E2 along the z direction. Magnetism can be reduced.

(Magnetic induction path formation method-homogenization model)
Next, a method for forming such a magnetic guiding path 40 will be described. In describing this method, first, a method for efficiently deriving the relative permeability of the magnetic rectangular tube 20 will be described. In the present embodiment, an actual model (hereinafter referred to as an actual model) of the magnetic rectangular tube 20 is replaced with an equivalent model (hereinafter referred to as a homogenization model) created by homogenizing using a homogenization method. By calculating the relative permeability of the homogenization model, the actual relative permeability of the magnetic rectangular tube 20 is derived. FIG. 4 is a perspective view of an actual magnetic rectangular cylinder 20, and FIG. 5 is a perspective view of a homogenization model. Here, roughly speaking, when a uniform magnetic field is applied to each of the real model and the homogenization model, the magnetic energy of each of the real model and the homogenization model is calculated, and the magnetic energy is mutually calculated. The calculation formula of the relative permeability of the homogenization model is derived on the condition that

  As shown in FIG. 4, the dimensions of the actual magnetic rectangular tube 20 are as follows: width = height = 296 mm, depth = 300 mm, thickness = 3.5 mm, and the gap between other adjacent actual magnetic rectangular tubes 20. = 2 mm, magnetic field magnitude = H, magnetic flux density = B, relative permeability = μ, and magnetic energy per unit volume of the actual magnetic rectangular cylinder 20 = X, this magnetic energy X is expressed by the equation (1 ).

  Here, when the relative permeability in the x direction = μx is derived, the total magnetic energy X (real) of the real model is subjected to a magnetic field analysis in which a uniform magnetic field Bx is applied in the x direction. It is expressed as (2). Here, ne = number of elements of the actual model, ie = value of the element ie, and V = volume of the actual model.

  On the other hand, the magnetic energy X (homo) in the homogenization model of the volume Vh shown in FIG. 5 is expressed as in Equation (3).

  Here, since the total magnetic energy X (real) of the real model and the magnetic energy X (homo) of the homogenization model are equal to each other, the relative permeability in the x direction of the homogenization model = μx is as follows. Equation (4) holds. The relative permeability in the y direction of the homogenization model = μy and the relative permeability in the z direction of the homogenization model = μz can be similarly derived.

(Formation method of magnetic induction path-relative permeability in x direction = adjustment method of μx)
Next, a method for adjusting the relative permeability in the x direction = μx will be described. FIG. 6 is a perspective view of the magnetic rectangular tube 20 (actual model) in which the relative permeability μx is adjusted. The magnetic rectangular cylinder 20 is configured to include a notch 30. This notch 30 is formed in each of the two side parts 21 along the x direction among the side parts 21 and 22 of the magnetic rectangular tube 20, and along the direction orthogonal to the x direction. Is formed.

  Thus, the change of the relative magnetic permeability at the time of forming the notch 30 was calculated using the above-mentioned homogenization model. The dimensions of the actual model shown in FIG. 6 are as follows: width = height = depth = 300 mm, thickness = 7 mm, gap with another adjacent actual magnetic rectangular cylinder 20 = 2 mm, and gap of the notch 30 = 5 mm. It was. Further, the relative magnetic permeability of the magnetic rectangular tube 20 before forming the notch 30 was set to μx = μy = 10000 and μz = 1000. And relative permeability (mu) x, (mu) y, (mu) z was computed about the homogenization model (same as FIG. 5) which homogenized this real model. Here, in the side part 21 in which the notch part 30 is formed, the width in the direction along the notch part 30 and the part that remains without being formed on the extension line of the notch part 30 The relative permeability μx, μy when the width (the length obtained by subtracting the length of the cutout portion 30 from the total length of the side portion 21; hereinafter referred to as the connecting length) is Wx, and the connecting length Wx is changed. , Μz was calculated.

  The calculation results are shown in FIG. As can be seen from this result, it was confirmed that μx decreases as the connecting length Wx decreases (the length of the cutout 30 increases). It was also confirmed that μy and μz did not change regardless of the connection length Wx. From these, by forming the notch portion 30 along the direction orthogonal to the x direction in the side portion 21 along the x direction among the side portions 21 and 22 of the magnetic rectangular tube body 20, x Only the relative permeability in the direction = μx can be adjusted, and μx can be adjusted to a desired value by changing the length of the notch 30. Further, as can be seen from the result of FIG. 7, the connecting length Wx and the relative permeability μx are not simply proportional, and as the connecting length Wx becomes shorter (as the notch 30 becomes longer). The relative magnetic permeability μx decreases to a quadratic curve. Such a relationship also applies to, for example, the relationship between the number of locations and widths that form the notch 30 and the relative permeability μx. That is, regarding the number of locations, in FIG. 6, the notch 30 is formed on each of the two side portions 21 along the x direction, but in the case of being formed on each of the two side portions 21 in this way. The relative magnetic permeability μx is not simply halved and is reduced by 20 to 30% compared to the relative magnetic permeability μx formed only on one side portion 21. Further, regarding the width, in FIG. 6, the width of the notch 30 is set to 5 mm. However, even if this width is doubled, the relative permeability μx is not simply halved but is reduced to a quadratic curve. However, if the total volume of the cutout portion 30 (length × width × thickness of the cutout portion 30) is constant, the cutout portion 30 is cut out as compared with the case where the length of the cutout portion 30 is increased. It has been confirmed that the relative permeability μx is reduced smoothly (with a small change) when the width of the portion 30 is increased so that the relative permeability μx changes slightly. It is preferable at the point which can be made. The tendency regarding the number of points and the width is the same for the y direction and the z direction.

(Method for forming magnetic induction path-y-direction relative permeability = μy adjustment method)
Next, a method for adjusting the relative permeability in the y direction = μy will be described. FIG. 8 is a perspective view of the magnetic rectangular tube 20 (actual model) in which the relative permeability μy is adjusted. The magnetic rectangular cylinder 20 is configured to include a notch 31. This notch portion 31 is formed in each of the two side portions 22 along the y direction among the side portions 21 and 22 of the magnetic rectangular tube 20, and along the direction perpendicular to the y direction. Is formed.

  Thus, the change of the relative magnetic permeability when the notch 31 was formed was calculated using the homogenization model described above. The dimensions of the actual model shown in FIG. 8, the relative permeability of the magnetic rectangular tube 20 before forming the notch 31, and the calculation conditions for the relative permeability μx, μy, μz are the same as those of the actual model shown in FIG. The relative permeability μx, μy, μz was calculated for a homogenized model obtained by homogenizing this real model (similar to FIG. 5). Here, the relative magnetic permeability μx, μy, μz was calculated when the connecting length Wy was changed.

  The calculation results are shown in FIG. As can be seen from this result, it was confirmed that μy becomes smaller as the connecting length Wy becomes smaller (as the length of the notch 31 becomes larger). It was also confirmed that μx and μz did not change regardless of the connection length Wy. From these, by forming the notch 31 along the direction orthogonal to the y direction in the side part 22 along the y direction among the side parts 21 and 22 of the magnetic rectangular tube 20, y Only the relative permeability of the direction = μy can be adjusted, and μy can be adjusted to a desired value by changing the length of the notch 31.

(Method of forming magnetic induction path--method of adjusting relative permeability in z direction = μz)
Next, a method for adjusting the relative permeability in the z direction = μz will be described. FIG. 10 is a perspective view of the magnetic rectangular tube 20 (actual model) in which the relative permeability μz is adjusted. The magnetic rectangular cylinder 20 is configured to include a notch 32. The notch 32 is formed in each of the four corners 23 of the magnetic rectangular cylinder 20 and is formed along a direction orthogonal to the z direction.

  Thus, the change of the relative magnetic permeability when the notch 32 was formed was calculated using the above-mentioned homogenization model. The dimensions of the actual model shown in FIG. 10, the relative permeability of the magnetic rectangular tube 20 before forming the notch 32, and the calculation conditions for the relative permeability μx, μy, μz are the same as those of the actual model shown in FIG. 6. The relative permeability μx, μy, μz was calculated for a homogenized model obtained by homogenizing this real model (similar to FIG. 5). Here, the relative magnetic permeability μx, μy, and μz were calculated when the connection length Wz was changed.

  The calculation results are shown in FIG. As can be seen from this result, it was confirmed that μz decreases as the connecting length Wz decreases (the length of the notch 32 increases). It was also confirmed that μx and μy did not change regardless of the connection length Wz. From these facts, only the relative permeability in the z direction = μz can be adjusted by forming the notch 32 along the direction orthogonal to the z direction at the corner 23 of the magnetic rectangular tube 20. By changing the length of the notch 32, μz can be adjusted to a desired value.

(Method of forming magnetic induction path-adjusting method of relative permeability in multiple directions)
Next, a method for simultaneously adjusting the relative permeability in a plurality of directions will be described. FIG. 12 is a perspective view of the magnetic rectangular tube 20 (actual model) in which the relative magnetic permeability μy and μz are adjusted. This magnetic rectangular tube 20 is configured to have the same notches 31 and 32 as those shown in FIGS.

  Thus, the change of the relative magnetic permeability when the notches 31 and 32 were formed was calculated by the same method as that when the relative magnetic permeability μy and μz were individually adjusted.

  The calculation results are shown in FIG. As can be seen from this result, even when the notch 31 and the notch 32 are formed at the same time, the characteristic of the relative permeability μy is the same as that when only the notch 31 is formed, and the relative permeability is the same. The characteristics of μz are the same as when only the notch 32 is formed, and the connecting length Wy does not affect μx and μz, and the connecting length Wz does not affect μx and μy. Was confirmed. For these reasons, when the notch 31 and the notch 32 are simultaneously formed in the magnetic rectangular cylinder 20, only the relative permeability in the y direction = μy and the relative permeability in the z direction = μz should be adjusted. By changing the length of the notches 31 and 32, μy and μz can be adjusted to desired values.

  Although the illustration of the results is omitted, the same results were confirmed when the same cutout portions 30 to 32 as those shown in FIGS. That is, also in this case, the characteristic of the relative permeability μx is the same as that when only the notch 30 is formed, and the characteristic of the relative permeability μy is the same as when only the notch 31 is formed. The characteristics of the relative magnetic permeability μz are the same as when only the notch 32 is formed, the connecting length Wx does not affect μy and μz, and the connecting length Wy is μx, μz. It was confirmed that the connecting length Wz does not affect μx and μy. For these reasons, when the notches 30 to 32 are simultaneously formed in the magnetic rectangular cylinder 20, the relative permeability in the x direction = μx, the relative permeability in the y direction = μy, and the relative permeability in the z direction. = [Mu] z can be adjusted, and [mu] x, [mu] y, [mu] z can be adjusted to desired values by changing the lengths of the notches 30-32.

(Method of forming magnetic induction path-Principle of adjusting relative permeability)
The principle that the relative permeability can be adjusted by forming the notches 30 to 32 as described above will be described. As an example, the flow of magnetic flux inside the magnetic rectangular cylinder 20 in which the notch 31 formed along the direction orthogonal to the y direction is formed in each of the two side portions 22 along the y direction will be described. To do. 14-16 is the figure which showed typically the flow of the magnetic flux in each of the some magnetic square cylinder 20 from which the formation state of the notch part 31 differs, and these some magnetic square cylinders 20, 14 is a diagram relating to the magnetic rectangular tube 20 in which the notch 31 is not formed, FIG. 15 is a diagram relating to the magnetic rectangular tube 20 in which the notch 31 is formed, and FIG. It is a figure regarding the magnetic square cylinder 20 at the time of cutting all. Here, it is assumed that a magnetic flux entering from the lower side to the upper side in the figure is incident.

  As shown in FIG. 14A, in the magnetic rectangular tube 20 in which the notch 31 is not formed, as shown in FIG. 14B, the magnetic flux is the entire area of the side portion 22 along the y direction. It flows through. On the other hand, as shown in FIG. 15A, in the magnetic rectangular tube 20 in which the notch 31 is formed, the magnetic flux is on the side along the y direction as shown in FIG. 15B. Of the portion 22, air does not flow through the notched portion 31 having a high magnetic resistance but flows only through a magnetic body portion (a portion other than the notched portion) having a low magnetic resistance. Further, as shown in FIG. 16 (a), in the completely cut magnetic square cylinder 20, as shown in FIG. 16 (b), the magnetic flux of the side portion 22 along the y direction is the magnetic resistance. Since there is no low magnetic part (a part other than the notch 31), the air flows and attenuates through the notch 31 having air and high magnetic resistance. From these facts, the wider the notch portions 30 to 32 and the longer the notch portions 30 to 32, the less the magnetic flux flows and the higher the magnetic resistance, thereby reducing the relative permeability. I understand that I can do it. In other words, the relative permeability in the desired direction can be reduced by forming the notches 30 to 32 in the specific direction and the specific location with the width and length that match the desired reduction amount of the relative permeability. It can be seen that the amount can be reduced.

(Relative permeability adjustment method of magnetic square tube)
Next, a method for adjusting the relative permeability of such a magnetic rectangular tube 20 will be described. The magnetic rectangular cylinder 20 is formed, for example, by bending a plate-like body of magnetic material by a method similar to the conventional method (preparation step). Then, in the stage before or after the folding, the slit-shaped notch is formed by pressing the cutter against the side portions 21 and 22 and the corner 23 of the plate-like body or the magnetic rectangular tube 20. (Cut part) 30-32 is put (notch part formation process). However, the notches 30 to 32 can be formed by other methods. For example, when the magnetic rectangular tube 20 is formed by casting, the notches 30 to 32 are also formed at the time of casting. Can do. Alternatively, the notches 30 to 32 may be formed by punching at a stage before the plate-like body of the magnetic material is bent or at a stage after the magnetic rectangular tube 20 is formed. Further, it is preferable that annealing is performed after the formation of the cutout portions 30 to 32 to improve the deterioration of the magnetic characteristics due to the distortion generated at the time of the cutout, and the relative permeability of each portion of the magnetic rectangular tube 20 is made uniform. .

(Magnetic induction path forming method-Modified example 1 of relative permeability adjustment)
Next, Modification Example 1 for adjusting the relative permeability will be described. The relative permeability in the x direction = μx and the relative permeability in the y direction = μy can be adjusted by adjusting the interval between the magnetic rectangular cylinders 20 in addition to forming the notch. it can.

  First, a method for adjusting the relative permeability in the x direction = μx will be described. FIG. 17 is a perspective view of the magnetic rectangular tube 20 (actual model) in which the relative permeability μx is adjusted. Here, the relative magnetic permeability μx in the x direction is adjusted by the interval (gap size Gx) between the magnetic rectangular cylinders 20 adjacent in the x direction. In addition, the space | interval between the magnetic square cylinders 20 adjacent along the y direction is fixed to a fixed value (here 2 mm). In the actual model shown in FIG. 17, the width of the magnetic rectangular tube 20 = height = depth = 300 mm, thickness = 7 mm, relative permeability μx = μy = 10000, and μz = 1000. And the relative magnetic permeability of 3 directions at the time of changing the gap dimension Gx in the homogenization model (similar to FIG. 5) with respect to this real model was calculated.

  The calculation result is shown in FIG. As can be seen from this result, it was confirmed that μx decreases as the gap dimension Gx increases. It was also confirmed that μy and μz did not change regardless of the gap dimension Gx. From these facts, μx can be adjusted to a desired value by changing the interval between the adjacent magnetic rectangular cylinders 20 along the x direction.

  Next, a method for adjusting the relative permeability in the y direction = μy will be described. FIG. 19 is a perspective view of the magnetic rectangular tube 20 (actual model) in which the relative permeability μy is adjusted. Here, the relative permeability μy in the y direction is adjusted by the interval (gap dimension Gy) between the magnetic square cylinders 20 adjacent in the y direction. In addition, the space | interval between the magnetic square cylinders 20 adjacent along the x direction is fixed to a fixed value (here 2 mm). Other conditions are the same as in FIG. And the relative magnetic permeability of 3 directions at the time of changing the gap dimension Gy in the homogenization model (similar to FIG. 5) with respect to this real model was calculated.

  The calculation results are shown in FIG. As can be seen from the results, it was confirmed that the larger the gap dimension Gy, the smaller μy. It was also confirmed that μx and μz did not change regardless of the gap dimension Gy. From these facts, μy can be adjusted to a desired value by changing the interval between the adjacent magnetic rectangular cylinders 20 along the y direction.

  Next, a method for simultaneously adjusting the relative permeability in a plurality of directions will be described. FIG. 21 is a perspective view of the magnetic rectangular tube 20 (actual model) in which the relative magnetic permeability μx and μy are adjusted. Here, the relative permeability μx in the x direction is adjusted by the interval (gap dimension Gx) between the magnetic rectangular cylinders 20 adjacent in the x direction, and at the same time, the relative permeability μy in the y direction is changed to the y direction. Is adjusted by the interval (gap dimension Gy) between the magnetic rectangular cylinders 20 adjacent to each other. Other conditions are the same as in FIG. Then, the relative permeability in three directions when the gap dimensions Gx and Gy were changed in the homogenization model (similar to FIG. 5) with respect to the actual model was calculated.

  The calculation result is shown in FIG. As can be seen from this result, even when the gap dimension Gx and the gap dimension Gy are simultaneously increased, the characteristic of the relative permeability μx is the same as that of the case where only the gap dimension Gx is increased, and the characteristic of the relative permeability μy. Is the same as when only the gap dimension Gy is increased, and it was confirmed that the gap dimension Gx does not affect μy and μz, and the gap dimension Gy does not affect μx and μz. Therefore, when the gap dimension Gx and the gap dimension Gy of the magnetic rectangular tube 20 are increased simultaneously, only the relative permeability in the x direction = μx and the relative permeability in the y direction = μy can be adjusted. By changing the gap dimensions Gx and Gy, μx and μy can be adjusted to desired values.

  As a specific structure for adjusting the gap dimension Gx and the gap dimension Gy in this way, for example, the thickness of each frame 10 is changed, or a nonmagnetic material is used between each frame 10 and the magnetic rectangular cylinder 20. A sandwiched structure can be adopted.

  According to the method according to the second modification example, by adjusting the gap dimension between the plurality of magnetic rectangular cylinders 20 constituting the magnetic shield body 1, a desired degree of ratio in the x direction and the y direction is achieved. The magnetic shield body 1 having magnetic permeability can be configured, the magnetism to be guided to a specific area of the magnetic shield body 1 can be reduced, and the magnetism leaking from the specific area of the magnetic shield body 1 can be reduced.

(Magnetic induction path forming method-Modified example 2 of relative permeability adjustment)
Next, a modified example 2 of the relative permeability adjustment will be described. The adjustment of the relative permeability in the z direction = μz can be performed by adjusting the thickness of the magnetic rectangular tube 20 in addition to forming the notch.

  FIG. 23 is a perspective view of the magnetic rectangular tube 20 (actual model) in which the relative permeability μz is adjusted. Here, the relative permeability μz in the z direction is adjusted by the thickness of the magnetic rectangular tube 20. In the actual model shown in FIG. 23, the width of the magnetic rectangular cylinder 20 = height = depth = 300 mm, the thickness = tmm, and the interval between the adjacent magnetic rectangular cylinders 20 along the x direction (gap dimension Gx). = Interval (gap dimension Gy) between adjacent magnetic square cylinders 20 along the y direction = 2 mm, relative permeability μx = μy = 10000, and μz = 1000. And the relative magnetic permeability of 3 directions when thickness t was changed in the homogenization model (similar to FIG. 5) with respect to this real model was calculated.

  The calculation results are shown in FIG. As can be seen from this result, it was confirmed that μz increases as the thickness t increases. It was also confirmed that μy and μz did not change regardless of the thickness t. From these facts, μz can be adjusted to a desired value by changing the thickness t of the magnetic rectangular tube 20.

  As a specific structure for adjusting the thickness t of the magnetic rectangular tube 20, for example, when the magnetic rectangular tube 20 is formed, the magnetic rectangular tube 20 is formed using magnetic plate materials having different thicknesses t. In this case, it is possible to adopt a structure in which the thickness t is changed at the time of casting or a magnetic body is attached to the side surface or the inner surface after the magnetic rectangular tube 20 having a standard thickness t is formed.

  According to the method according to the second modification, the magnetic shield body 1 having a desired degree of relative permeability in the z direction is obtained by adjusting the thicknesses of the plurality of magnetic rectangular cylinders 20 constituting the magnetic shield body 1. It is possible to reduce the magnetism induced to a specific region of the magnetic shield body 1 and to reduce the magnetism leaking from the specific region of the magnetic shield body 1.

(Effect of magnetic guiding path in magnetic shield body)
Next, the result of verifying the effect of forming the magnetic guiding path 40 on the magnetic shield body 1 by three-dimensional magnetic analysis will be described. Here, an analysis model is created for each of the magnetic shield body 1 that is not provided with a large opening and the magnetic shield body 1 that is provided with a large opening in order to reduce the feeling of pressure on the occupant, and using this analysis model, When the magnetic induction path 40 is not formed (when the relative permeability of the magnetic rectangular tube is not optimized), the leakage magnetic flux density on the evaluation surface when the magnetism generated from the magnetic source is applied is determined. When formed (when the relative magnetic permeability of the magnetic rectangular tube was optimized), it was determined respectively.

  25 is an elevation view of the magnetic shield body 1 without a large opening, FIG. 26 is an elevation view of the magnetic shield body 1 with a large opening, and FIG. It is a longitudinal cross-sectional view. These magnetic shield bodies 1 show only a quarter region in consideration of symmetry. The magnetic shield body 1 in FIG. 25 is configured only by the magnetic square cylinder 20 with height = width = depth = 300 mm, and the magnetic shield body 1 in FIG. 26 has a magnetic angle with height = width = depth = 300 mm. In addition to the cylindrical body 20A, a magnetic square tube 20B having a large opening with height = width = 2400 mm and depth = 300 mm is used. Here, as shown in FIG. 27, the magnetic shield body 1 is arranged 2300 mm apart from the magnetic generation source (electromagnetic coil having magnetomotive force of 40000 AT), and on the opposite side of the magnetic generation source with the magnetic shield body 1 interposed therebetween. An evaluation surface is set at a position 300 mm away.

  FIG. 28 is a perspective view of an analysis model of the magnetic shield body 1 of FIG. 25, and FIG. 29 is a perspective view of an analysis model of the magnetic shield body 1 of FIG. These analysis models are created as ¼ area models in consideration of symmetry. Here, as the reduction target region E2, a region corresponding to the large opening magnetic cylinder 20A in FIG. 25 is set in each region on the evaluation surface.

  Further, the relative permeability μx, μy, μz in the three directions of the magnetic rectangular tube 20 is derived by the homogenization method described above. FIG. 30 is a perspective view of a magnetic rectangular tube (actual model) constituting the magnetic shield body 1 of FIGS.

  Specifically, the relative permeability in the three directions derived by the homogenization method using the homogenization model (similar to FIG. 5) is used as the ratio of each direction of each magnetic body rectangular tube 20 in the analysis models of FIGS. Set to the initial value for permeability. Then, an iterative analysis was performed to optimize (minimize) the relative permeability of each magnetic material rectangular tube so that the leakage magnetic flux density in the reduction target region E2 is reduced with the relative permeability of each part as a maximum value.

  The leakage magnetic flux density on the evaluation surface when a magnetic field generated from a magnetic field generation source was applied to the analysis model of FIG. 28 was determined by three-dimensional magnetic field analysis. FIG. 31 shows the result when the magnetic guiding path 40 is not formed, and FIG. 32 shows the result when the magnetic guiding path 40 is formed. As is apparent from FIGS. 31 and 32, the maximum leakage magnetic flux density (about 5E-5 (T)) in the reduction target region E2 when the magnetic guide path 40 is formed is reduced when the magnetic guide path 40 is not formed. It is smaller than the maximum leakage magnetic flux density (about 8E-5 (T)) in the target region E2.

  Further, FIG. 33 shows the magnitude and direction of the magnetic flux distribution when the magnetic guiding path 40 is not formed, and FIG. 34 shows the magnitude and direction of the magnetic flux distribution when the magnetic guiding path 40 is formed. In FIGS. 33 and 34, the magnitude of the magnetic flux distribution is indicated by the length of the arrow, and the direction of the magnetic flux distribution is indicated by the direction of the arrow (the same applies to the drawings showing the magnitude and direction of the magnetic flux distribution). As is apparent from FIGS. 33 and 34, when the magnetic guide path 40 is formed, the magnetic flux generated from the magnetic field generation source and incident on the magnetic shield body 1 is smaller than when the magnetic guide path 40 is not formed. It can be seen that the flow is made to avoid the reduction target area E2. From this, it was confirmed that by forming the magnetic guiding path 40, the density of the magnetic flux flowing in the reduction target region E2 can be reduced, and the maximum leakage magnetic flux density in the reduction target region E2 can be reduced.

  Further, the leakage magnetic flux density on the evaluation surface when a magnetic field generated from a magnetic field generation source was applied to the analysis model of FIG. 29 was obtained by three-dimensional magnetic field analysis. FIG. 35 shows the result when the magnetic guiding path 40 is not formed, and FIG. 36 shows the result when the magnetic guiding path 40 is formed. As is clear from FIGS. 35 and 36, even when a large opening is formed, the maximum leakage magnetic flux density (about 7E-5 (T)) in the reduction target region E2 when the magnetic guiding path 40 is formed is This is smaller than the maximum leakage magnetic flux density (about 13E-5 (T)) in the reduction target region E2 when the magnetic guiding path 40 is not formed.

  Further, FIG. 37 shows the magnitude and direction of the magnetic flux distribution when the magnetic guiding path 40 is not formed, and FIG. 38 shows the magnitude and direction of the magnetic flux distribution when the magnetic guiding path 40 is formed. As is apparent from FIGS. 37 and 38, even when the large opening is formed, the magnetic induction path 40 is generated from the magnetic field generation source as compared with the case where the magnetic induction path 40 is not formed. Thus, it can be seen that the magnetic flux incident on the magnetic shield body 1 flows so as to avoid the magnetic opening 20B having a large opening. From this, it was confirmed that by forming the magnetic guiding path 40, the density of the magnetic flux flowing through the magnetic rectangular cylinder 20B having a large opening can be reduced, and the maximum leakage magnetic flux density in the reduction target region E2 can be reduced.

  Further, the leakage magnetism in the application region E1 in the magnetic shield body 1 not provided with the large opening was also analyzed. FIG. 39 is a perspective view of an analysis model of the magnetic shield body 1 similar to FIG. 25, and shows a state in which the application region E1 of height = width = 1200 mm is set as the reduction target region E2. The leakage magnetic flux density on the evaluation surface when a magnetic field generated from a magnetic field generation source was applied to this analysis model was determined by three-dimensional magnetic field analysis. FIG. 40 shows the result when the magnetic guiding path 40 is not formed, and FIG. 41 shows the result when the magnetic guiding path 40 is formed. As apparent from FIGS. 40 and 41, the maximum leakage magnetic flux density (about 14E-5 (T)) in the application region E1 when the magnetic induction path 40 is formed is the application region when the magnetic induction path 40 is not formed. It is about 40% smaller than the maximum leakage magnetic flux density at E1 (about 24E-5 (T)). From this, it was confirmed that the maximum leakage magnetic flux density in the application region E1 can be reduced by forming the magnetic guiding path 40.

(Effect of Embodiment 1)
As described above, according to the first embodiment, the magnetic field from the application region E1 to which the strongest magnetism from the magnetic source is applied in the region in the magnetic shield body 1 to the outside in the region in the magnetic shield body 1 is applied. Since the magnetic guide path 40 for reducing the leakage magnetism from the reduction target region E2 to the outside by guiding the magnetism to the region other than the reduction target region E2 where leakage is desired to be reduced, the magnetic shield body 1 is provided with the magnetic shield. The incident magnetism can be guided to a region other than the reduction target region E2 via the magnetic guide path 40, and the magnetism transmitted to the reduction target region E2 can be reduced, so that the magnetism leaking from the reduction target region E2 can be reduced. Therefore, even when a large opening is provided in the reduction target area E2, magnetism leaking from the large opening can be reduced, and providing the large opening can reduce the feeling of pressure on the occupant and at the same time Magnetic shielding performance can be ensured.

  Further, the relative permeability of a part of the plurality of magnetic rectangular cylinders 20 and the magnetic permeability along the z direction that is the cylinder axis direction of the magnetic rectangular cylinder 20, or , At least one of the relative magnetic permeability along the direction orthogonal to the z direction is different from the relative magnetic permeability in the same direction in the other magnetic rectangular cylinders 20 among the plurality of magnetic rectangular cylinders 20. Thus, since the magnetic guiding path 40 is formed, the relative permeability in a desired direction according to the positional relationship between the application region E1 and the reduction target region E2 can be adjusted. Magnetism leaking from the target region E2 can be reduced.

  Further, out of the relative magnetic permeability of some of the magnetic rectangular cylinders 20, the relative magnetic permeability along the z direction, the direction orthogonal to the z direction and the x direction orthogonal to one side surface of the magnetic rectangular cylinder 20 The relative permeability along the same direction in the other magnetic rectangular cylinder 20 is the relative permeability along the z direction and the relative permeability along the y direction orthogonal to the x direction. Since the magnetic induction path 40 is formed by setting the relative permeability to be different, even when the magnetic rectangular tube 20 is formed as the magnetic rectangular tube 20, a desired response according to the positional relationship between the application region E1 and the reduction target region E2 The relative magnetic permeability in the direction can be adjusted, and in various magnetic shield bodies 1, the magnetism leaking from the reduction target region E2 can be reduced.

  Further, the relative magnetic permeability of the magnetic rectangular tube 20 arranged in the shortest region E3 on the shortest path from the application region E1 to the reduction target region E2 is made smaller than the relative magnetic permeability of the other magnetic rectangular tube 20. Thus, since the magnetic guiding path 40 is formed in a region other than the shortest region E3, the magnetism induced in the shortest route from the application region E1 to the reduction target region E2 can be reduced, and the magnetism induced in the reduction target region E2 Can be reduced.

  Further, the relative magnetic permeability in the z direction of the magnetic rectangular tube 20 included in the reduction target region E2 is the same in the other magnetic rectangular tubes 20 arranged in the peripheral region E4 around the reduction target region E2. Since the magnetic induction path 40 is formed in a region other than the surrounding region E4 by reducing the relative permeability along the direction, magnetism that leaks from the surrounding region E4 to the outside of the magnetic shield body 1 along the z direction. It can reduce, and the magnetism which leaks from the reduction object field E2 along the z direction can be reduced.

  Further, the relative permeability along the z direction of the magnetic rectangular tube 20 included in the reduction target region E2 is included in the opposite region E5 located on the opposite side of the application region E1 across the reduction target region E2. Since the magnetic induction path 40 is formed in the opposite region E5 by increasing the relative magnetic permeability along the same direction in the other magnetic rectangular cylinder 20 to be magnetically shielded, the magnetic shield body 1 extends from the opposite region E5 along the z direction. Increasing the magnetism leaking to the outside of the magnet can reduce magnetism leaking from the reduction target area E2 along the z direction.

  In addition, the magnetic square cylinder 20 has cutout portions 30 to 32 formed on the side surfaces 21 and 22 or the corner portions 23 of the magnetic square cylinder body 20 in a direction orthogonal to the cutout portions 30 to 32. Is a cutout portion 30 to 32 for reducing the relative permeability along the relative permeability in the same direction in the magnetic rectangular tube 20 having the same shape without the cutout portions 30 to 32, and the relative permeability Since the relative permeability of the magnetic rectangular tube 20 is adjusted by providing the notches 30 to 32 formed with the length and width corresponding to the required reduction amount, the required direction (vertical direction, horizontal direction, And one or more directions arbitrarily selected from the three directions in the depth direction) can be reduced by a required reduction amount, and the relative permeability in each direction for each magnetic rectangular tube 20 can be easily achieved. Can be adjusted. In particular, since the relative permeability can be adjusted by forming the notches 30 to 32, the mutual spacing of the magnetic rectangular cylinders 20, the shape other than the notches 30 to 32, the thickness, etc. can be made constant. There is no increase in manufacturing and management effort of the rectangular tube body 20, the assembly of the magnetic shield body is easy, and the design of the magnetic shield body 1 is not lowered.

  Further, a part of the magnetic rectangular cylinders 20 is formed as a large opening magnetic rectangular cylinder 20B having an opening larger than that of the other magnetic rectangular cylinders 20, and is applied from the application region E1 to a region other than the large opening magnetic rectangular tube 20B. Since the magnetic induction path 40 for reducing the leakage magnetism from the large opening magnetic rectangular tube 20B to the outside by inducing magnetism is provided, the magnetism incident on the magnetic shield body 1 from the magnetic source is converted into the magnetic induction path 40. Thus, it is possible to guide to a region other than the large opening magnetic rectangular cylinder 20B, and to reduce the magnetism transmitted to the large opening magnetic rectangular cylinder 20B, thereby reducing the magnetism leaking from the large opening magnetic rectangular cylinder 20B. . Therefore, even when the large opening magnetic rectangular tube 20B is provided, the magnetism leaking from the large opening magnetic rectangular tube 20B can be reduced, and by providing the large opening magnetic rectangular tube 20B, A feeling of pressure can be reduced and at the same time required magnetic shielding performance can be ensured.

  In addition, since the frame 10 is formed of a conductive material, an electromagnetic wave shielding effect can be obtained, and even when the magnetism from the magnetic source fluctuates, the fluctuation magnetism can be reduced by the effect of eddy current. it can.

[Embodiment 2]
Next, the magnetic shield body according to the second embodiment will be described. This form is a form in which large openings are continuously formed. However, the configuration not particularly described is the same as the configuration of the first embodiment, and the same configuration as that of the first embodiment is denoted by the same reference numerals as those used in the first embodiment, as necessary. Description is omitted.

(Constitution)
FIG. 42 is an elevation view of the magnetic shield body according to the present embodiment. This magnetic shield body 2 is configured by continuously arranging magnetic square cylinders 20B having large openings along the width direction (x direction).

(Configuration-magnetic induction path 40)
The magnetic shield body 2 configured as described above includes a magnetic guiding path 40. FIG. 43 is an explanatory diagram for conceptually explaining the magnetic guiding path 40, and here, only the ¼ region is shown in consideration of the symmetry of the magnetic shield body 2. This magnetic guiding path 40 reduces the leakage magnetism from the reduction target region E2 to the outside by guiding magnetism from the application region E1 to a region other than the reduction target region E2.

  Here, the formation position of the magnetic guiding path 40 is specified by the first to third methods. That is, the relative permeability of the magnetic rectangular tube 20 arranged in the shortest region E3 on the shortest path from the application region E1 to the reduction target region E2 is made smaller than the relative permeability of the other magnetic rectangular tubes 20. Yes. Further, the relative magnetic permeability of the magnetic square cylinder 20 arranged in the avoidance area on the path from the application area E1 to the area other than the reduction target area E2 without passing through the reduction target area E2 is set to the other magnetic square cylinder 20. The relative permeability is larger. In addition, in the relative magnetic permeability μz along the z direction of the magnetic rectangular tube 20 included in the reduction target region E2, in the other magnetic rectangular tube 20 disposed in the peripheral region E4 around the reduction target region E2. The relative magnetic permeability μx and μy along the same direction are reduced. Furthermore, with respect to the relative magnetic permeability μz along the z direction of the magnetic rectangular tube 20 included in the reduction target region E2, the reduction target region E2 is located on the opposite side of the application region E1. The relative magnetic permeability along the same direction in the other magnetic rectangular tube 20 included in the opposite region E5 is increased.

(Effect of magnetic guiding path in magnetic shield body)
Next, the result of verifying the effect of forming the magnetic guiding path 40 on the magnetic shield body 2 by three-dimensional magnetic analysis will be described. FIG. 44 is an elevational view of the magnetic shield body 2. This magnetic shield body 2 shows only a quarter region in consideration of symmetry. The magnetic shield body 2 is configured by using a magnetic square tube having a large opening with height = width = 600 mm and depth = 300 mm in addition to a magnetic square tube with height = width = depth = 300 mm. Other conditions are the same as in FIG.

  FIG. 45 is a perspective view of an analysis model of the magnetic shield body 2 of FIG. This analysis model is created as a ¼ area model in consideration of symmetry. Here, as the reduction target region E2, a region corresponding to the large-diameter magnetic body rectangular tube 20B in FIG. 44 is set in each region on the evaluation surface.

  Further, the relative permeability μx, μy, μz in the three directions of the magnetic rectangular tube 20 is derived by the homogenization method described above. 46 is a perspective view of the magnetic body rectangular tube 20 (actual model) constituting the magnetic shield body 2 of FIG. 44, and FIG. 47 is a perspective view of the homogenization model.

  Specifically, the relative permeability in three directions derived by the homogenization method using the homogenization model in FIG. 47 is used as the initial value of the relative permeability in each direction of each magnetic body rectangular tube 20 in the analysis model in FIG. Set to. Then, iterative analysis was performed to optimize (minimize) the relative permeability of each magnetic body rectangular tube 20 so that the leakage magnetic flux density in the reduction target region E2 is reduced with the relative permeability of each part as a maximum value. .

  The leakage magnetic flux density on the evaluation surface when a magnetic field generated from a magnetic field generation source was applied to the analysis model of FIG. 47 was determined by three-dimensional magnetic field analysis. FIG. 48 shows the result when the magnetic guiding path 40 is not formed, and FIG. 49 shows the result when the magnetic guiding path 40 is formed. As is apparent from FIGS. 48 and 49, the maximum leakage magnetic flux density (about 6E-5 (T)) in the reduction target region E2 when the magnetic guiding path 40 is formed is reduced when the magnetic guiding path 40 is not formed. It is smaller than the maximum leakage magnetic flux density (about 11E-5 (T)) in the target region E2.

  Further, FIG. 50 shows the magnitude and direction of the magnetic flux distribution when the magnetic guiding path 40 is not formed, and FIG. 51 shows the magnitude and direction of the magnetic flux distribution when the magnetic guiding path 40 is formed. As is apparent from FIGS. 50 and 51, when the magnetic guiding path 40 is formed, the magnetic flux generated from the magnetic field generation source and incident on the magnetic shield body 2 is smaller than when the magnetic guiding path 40 is not formed. It can be seen that the flow is made to avoid the reduction target area E2. From this, it was confirmed that by forming the magnetic guiding path 40, the density of the magnetic flux flowing in the reduction target region E2 can be reduced, and the maximum leakage magnetic flux density in the reduction target region E2 can be reduced. In FIG. 51, although it seems that a part of the magnetic flux also flows in the reduction target region E2 in the reduction target region E2, here, the ratio of the magnetic body rectangular tube 20 in the reduction target region E2 in the z direction Since the magnetic permeability is reduced, the magnetic flux that has flowed in the reduction target region E2 does not flow in the z direction, and further flows toward the opposite region E5 (the region above the reduction target region E2). It was confirmed that the magnetism leaked from E2 could be reduced.

(Effect of Embodiment 2)
Thus, according to the second embodiment, the same effect as in the first embodiment can be obtained. Particularly, since the magnetic shield body 2 is configured by continuously arranging the large-sized magnetic square cylinders 20 along the width direction, the feeling of pressure is further increased than the magnetic shield body 1 of the first embodiment. Can be provided.

[Embodiment 3]
Next, the magnetic shield body according to Embodiment 3 will be described. In this form, a cylindrical shield constituted by a magnetic cylinder and a plate shield constituted by a magnetic plate are arranged so as to contact each other. However, the configuration not particularly described is the same as the configuration of the first embodiment, and the same configuration as that of the first embodiment is denoted by the same reference numerals as those used in the first embodiment, as necessary. Description is omitted.

(Constitution)
FIG. 52 is an elevation view of the magnetic shield body according to the present embodiment. This magnetic shield body 3 includes a cylindrical shield 50 constituted by a plurality of magnetic square cylinders 20 arranged in parallel with each other through a frame 10, and a plate constituted by a magnetic plate-like body 51. The shields 52 are arranged so as to be in contact with each other. Since the cylindrical shield 50 can be configured in the same manner as the magnetic shield 1 of the first embodiment, the basic description thereof is omitted. The plate-like shield 52 is configured by arranging a plurality of horizontally oriented directional silicon steel plates having the x direction as a longitudinal direction. The plurality of grain-oriented silicon steel plates are connected to each other by welding or the like. In addition, in order to improve the designability, a decorative plate may be fixed to the outside of the plurality of directional silicon steel plates.

(Configuration-magnetic taxiway)
The magnetic shield body 3 configured as described above includes a magnetic guiding path 40. FIG. 53 is an explanatory diagram for conceptually explaining the magnetic guiding path 40, and here, only the ½ region is shown in consideration of the symmetry of the magnetic shield body 3. This magnetic guiding path 40 reduces the leakage magnetism from the reduction target region E2 to the outside by guiding magnetism from the application region E1 to a region other than the reduction target region E2.

  Here, the formation position of the magnetic guiding path 40 is specified by the first to third methods. That is, the relative permeability of the magnetic rectangular tube 20 arranged in the shortest region E3 on the shortest path from the application region E1 to the reduction target region E2 is made smaller than the relative permeability of the other magnetic rectangular tubes 20. Yes. Further, the relative magnetic permeability of the magnetic square cylinder 20 arranged in the avoidance area on the path from the application area E1 to the area other than the reduction target area E2 without passing through the reduction target area E2 is set to the other magnetic square cylinder 20. The relative permeability is larger. Further, the relative magnetic permeability in the z direction of the magnetic rectangular tube 20 included in the reduction target region E2 is the same in the other magnetic rectangular tubes 20 arranged in the peripheral region E4 around the reduction target region E2. The relative permeability along the direction is reduced. However, in this magnetic shield body 3, since there is no opposite region E5 located on the opposite side of the application region E1 across the reduction target region E2, the setting of the relative magnetic permeability for the opposite region E5 is omitted. .

  However, unlike the first and second embodiments, the magnetic guiding path 40 in the present embodiment is formed on the plate-shaped shield 52. Specifically, the magnetic guiding path 40 is formed by using a directional silicon steel plate. That is, the grain-oriented silicon steel sheet is formed by aligning the axial direction of crystal grains by adjusting rolling conditions and heat treatment conditions, and has a large relative permeability in a specific direction. And the magnetic induction path 40 is formed by arrange | positioning a directional silicon steel plate so that the direction where this relative permeability is large follows ax direction. According to such a configuration, since the magnetism incident on the plate-like shield 52 from the magnetic source is guided along the x direction, the magnetism transmitted from the plate-like shield 52 to the cylindrical shield 50 can be reduced. The magnetism leaking from the reduction target area E2 can be reduced.

(Effect of Embodiment 3)
As described above, according to the third embodiment, the cylindrical shield 50 constituted by the plurality of magnetic rectangular cylinders 20 and the plate-like shield 52 constituted by the magnetic plate-like body 51 are brought into contact with each other. The magnetic guide path 40 is provided in the plate-shaped shield 52, and the magnetic guide path 40 allows magnetism to be applied from the application region E 1 in the plate-shaped shield 52 to a region other than the cylindrical shield 50. Since induction is performed, the magnetism incident on the plate-shaped shield 52 from the magnetic source can be guided to a region other than the cylindrical shield 50 via the magnetic guide path 40, and the magnetism transmitted to the cylindrical shield 50 can be reduced. Therefore, the magnetism leaking from the cylindrical shield 50 can be reduced. Therefore, even when the cylindrical shield 50 is provided with a large opening, the magnetism leaking from the large opening magnetic rectangular cylinder 20 can be reduced.

[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. For example, as a magnetic cylinder for constituting the magnetic shield body, a cylindrical magnetic cylinder as described in Patent Document 1 may be used instead of the square cylinder-shaped magnetic square cylinder 20. Good. In this case, the relative permeability of a part of the plurality of magnetic cylinders, the relative permeability along the z direction that is the cylinder axis direction of the magnetic cylinder, or in the z direction By setting at least one of the relative permeability along the orthogonal direction to be different from the relative permeability in the same direction in the other magnetic cylinders of the plurality of magnetic cylinders, What is necessary is just to form. Similarly, even when the magnetic cylinder is a rectangular cylinder, a triangular prism, a hexagonal cylinder, or various shapes of the magnetic rectangular cylinder 20 can be used.

(About the mutual relationship of each embodiment)
The configurations described in the embodiments may be combined with each other. For example, in the magnetic shield body constituted by the cylindrical shield 50 and the plate shield 52 as in the third embodiment, the magnetic guide path 40 is provided in the plate shield 52 as described in the third embodiment. In addition, the magnetic guide path 40 may be formed in the cylindrical shield 50 as in the first and second embodiments. Further, when the magnetic guiding path 40 is formed in the cylindrical shield 50, in addition to the provision of notches in some of the magnetic rectangular cylinders 20 as in the first embodiment, a modification of the first embodiment 1 may be combined with changing the interval between some of the magnetic square cylinders 20 or changing the thickness of some of the magnetic square cylinders 20 as in the second modification of the first embodiment.
(Appendix)
In order to solve the above-described problems and achieve the object, the magnetic shield body described in Supplementary Note 1 is a magnetic shield body including a plurality of magnetic cylinders arranged in parallel with each other through a supporting means. From the application region where the strongest magnetism from the magnetic source is applied in the region of the magnetic shield body, the region other than the reduction target region in the region of the magnetic shield body where the magnetic leakage to the outside is to be reduced In addition, a magnetic guide path is provided for reducing the leakage magnetism from the reduction target area to the outside by inducing magnetism.
The magnetic shield body described in appendix 2 is the magnetic shield body according to appendix 1, wherein the magnetic shield body has a relative permeability of a part of the plurality of magnetic cylinders, and the cylinder axis of the magnetic cylinder At least one of the relative permeability along the z direction, which is the direction, or the relative permeability along the direction orthogonal to the z direction, in the same direction in the other magnetic cylinders of the plurality of magnetic cylinders. The magnetic induction path was formed by setting the relative permeability different from the relative permeability.
The magnetic shield body according to appendix 3 is the magnetic shield body according to appendix 2, in which the magnetic cylinder is a square cylinder-shaped magnetic square cylinder, of the relative permeability of the part of the magnetic cylinders The relative magnetic permeability along the z direction, the relative magnetic permeability along the x direction that is orthogonal to the z direction and orthogonal to one side surface of the magnetic cylinder, or the z direction and the x direction The magnetic induction path was formed by setting at least one of the relative permeability along the orthogonal y direction to be different from the relative permeability along the same direction in the other magnetic cylinder.
The magnetic shield body according to appendix 4 is the magnetic shield body according to appendix 2 or 3, wherein the relative permeability of the magnetic cylinder disposed in the shortest area on the shortest path from the application area to the reduction target area. The magnetic induction path was formed in a region other than the shortest region by making the magnetic permeability smaller than the relative magnetic permeability of other magnetic cylinders.
The magnetic shield body according to appendix 5 is the magnetic shield body according to any one of appendices 2 to 4, with respect to the relative magnetic permeability along the z direction of the magnetic cylinder included in the reduction target region. Thus, the magnetic induction path is formed in a region other than the surrounding region by reducing the relative permeability along the same direction in the other magnetic cylinders arranged in the surrounding region around the reduction target region.
The magnetic shield body according to appendix 6 is the magnetic shield body according to any one of appendices 2 to 5, with respect to the relative permeability along the z direction of the magnetic cylinder included in the reduction target region. By increasing the relative permeability along the same direction in the other magnetic cylinder included in the opposite region located on the opposite side of the application region across the reduction target region, the opposite region is A magnetic induction path was formed.
The magnetic shield body according to appendix 7 is the magnetic shield body according to any one of appendices 2 to 6, wherein the magnetic cylinder includes a notch formed on a side surface or a corner of the magnetic cylinder. And a notch portion for reducing a relative permeability along a direction orthogonal to the notch portion from a relative permeability in the same direction in a magnetic rectangular tube having the same shape without the notch portion. The relative permeability of the magnetic cylinder was adjusted by providing a notch portion formed with a length and a width corresponding to a required reduction amount of the relative permeability.
The magnetic shield body according to appendix 8 is the cylindrical shield body constituted by the plurality of magnetic cylinders arranged in parallel with each other through the support means in the magnetic shield body according to appendix 1. And a plate-shaped shield constituted by a magnetic plate-like body are arranged so as to contact each other, the magnetic shield path is provided in the plate-like shield body, and the plate-like shield is formed by the magnetic guide path. Magnetism is induced from the application region in the shield to a region other than the cylindrical shield.
The magnetic shield body according to appendix 9 is a magnetic shield body including a plurality of magnetic cylinders arranged in parallel with each other through a support means, and a part of the plurality of magnetic cylinders The magnetic cylinder is formed as a large-aperture magnetic cylinder having an opening larger than that of the other magnetic cylinder, and the application area where the strongest magnetism from the magnetic source is applied among the areas in the magnetic shield body, A magnetic induction path is provided that reduces the leakage magnetism from the large opening magnetic cylinder to the outside by inducing magnetism in an area other than the large opening magnetic cylinder in the area of the magnetic shield body.
The magnetic shield body according to appendix 10 is the magnetic shield body according to any one of appendices 1 to 9, wherein the support means is formed of a conductive material.
(Additional effects)
According to the magnetic shield body described in appendix 1, magnetic leakage from the application area where the strongest magnetism from the magnetic source is applied in the area of the magnetic shield body to the outside in the area of the magnetic shield body. A magnetic guide path that reduces leakage magnetism from the reduction target area to the outside by guiding the magnetism to areas other than the reduction target area to be reduced is provided. Since it can be guided to a region other than the reduction target region via the guide path and the magnetism transmitted to the reduction target region can be reduced, the magnetism leaking from the reduction target region can be reduced. Therefore, even when a large opening is provided in the reduction target area, the magnetism leaking from the large opening can be reduced, and by providing the large opening, the feeling of pressure on the occupant can be reduced, and at the same time, the required magnetism Shielding performance can be ensured.
According to the magnetic shield body described in appendix 2, the relative permeability of a part of the plurality of magnetic cylinders and the ratio along the z direction that is the cylinder axis direction of the magnetic cylinder. At least one of the magnetic permeability and the relative magnetic permeability along the direction orthogonal to the z direction is different from the relative magnetic permeability in the same direction in other magnetic cylinders in the plurality of magnetic cylinders. Since the magnetic induction path is formed, the relative permeability in a desired direction can be adjusted according to the positional relationship between the application region and the reduction target region, and leakage from the reduction target region can be achieved in various magnetic shield bodies. The magnetism to be reduced can be reduced.
According to the magnetic shield body according to appendix 3, the magnetic cylinder is a square cylinder-shaped magnetic square cylinder, and among the relative permeability of some of the magnetic cylinders, the relative permeability along the z direction, At least a relative permeability along the x direction perpendicular to the z direction and perpendicular to one side surface of the magnetic cylinder, or at least a relative permeability along the y direction perpendicular to the z direction and the x direction. Since the magnetic induction path is formed by setting one to a relative permeability different from the relative permeability along the same direction in the other magnetic cylinder, even when the magnetic cylinder is formed as a magnetic square cylinder The relative permeability in a desired direction can be adjusted according to the positional relationship between the application region and the reduction target region, and the magnetism leaking from the reduction target region can be reduced in various magnetic shield bodies.
According to the magnetic shield body described in appendix 4, the relative permeability of the magnetic cylinder disposed in the shortest area on the shortest path from the application area to the reduction target area is more than the relative permeability of other magnetic cylinders. By reducing the size, a magnetic guiding path is formed in a region other than the shortest region. Therefore, the magnetism induced in the shortest route from the application region to the reduction target region can be reduced, and the magnetism induced in the reduction target region is reduced. can do.
According to the magnetic shield body described in appendix 5, with respect to the relative magnetic permeability along the z direction of the magnetic cylinder included in the reduction target area, the other magnetic cylinders arranged in the surrounding area around the reduction target area By reducing the relative permeability along the same direction in the body, a magnetic guiding path is formed in a region other than the surrounding region, thereby reducing magnetism leaking from the surrounding region to the outside of the magnetic shield body along the z direction. It is possible to reduce the magnetism that leaks from the reduction target region along the z direction.
According to the magnetic shield body described in appendix 6, the relative permeability along the z direction of the magnetic cylinder included in the reduction target region is located on the opposite side of the application region with the reduction target region interposed therebetween. By increasing the relative permeability along the same direction in the other magnetic cylinders included in the opposite region, a magnetic induction path is formed in the opposite region, so that the outside of the magnetic shield body extends from the opposite region along the z direction. Increasing the magnetism leaking to the magnetic field can reduce the magnetism leaking from the reduction target region along the z direction.
According to the magnetic shield body described in appendix 7, the magnetic cylinder has a notch portion formed on a side surface or a corner portion of the magnetic cylinder body, and the relative permeability along the direction orthogonal to the notch portion. This is a notch for reducing the magnetic permeability from the relative permeability in the same direction in a magnetic rectangular tube of the same shape without the notch, and the length and width corresponding to the required amount of reduction of the relative permeability. Since the relative permeability of the magnetic cylindrical body is adjusted by providing the notch portion formed in the above, one or more arbitrarily selected from the required direction (vertical direction, horizontal direction, and depth direction) The relative magnetic permeability in the respective directions can be easily adjusted for each magnetic rectangular tube. In particular, since the relative permeability can be adjusted by forming a notch, the mutual spacing of the magnetic square cylinders, the shape and thickness other than the notch can be made constant, and the manufacture and management of the magnetic square cylinder No increase in labor is required, the assembly of the magnetic shield body is easy, and the design of the magnetic shield body is not lowered. For example, in the magnetic shield body of the MRI room, even if the direction and angle of the magnetic field change with the replacement of the MRI, the height, width, and depth of each magnetic square tube body are the same. The support means can be dealt with by replacing the magnetic rectangular cylinders that differ only in the notch portions.
According to the magnetic shield body described in appendix 8, the cylindrical shield body constituted by a plurality of magnetic cylinder bodies and the plate shield body constituted by the magnetic plate bodies are arranged so as to be in contact with each other. Constructed, a magnetic guide path is provided in the plate-shaped shield, and the magnetic guide path induces magnetism from the application area in the plate-shaped shield to an area other than the cylindrical shield. The magnetism incident on the shield can be guided to a region other than the cylindrical shield via the magnetic guiding path, and the magnetism transmitted to the cylindrical shield can be reduced, thereby reducing the magnetism leaking from the cylindrical shield. Can do. Therefore, even when a large opening is provided in the cylindrical shield, the magnetism leaking from the large opening magnetic cylinder can be reduced.
According to the magnetic shield body of appendix 9, a part of the magnetic cylinders is formed as a large opening magnetic cylinder having an opening larger than that of the other magnetic cylinders, and the area other than the large opening magnetic cylinder from the application area In addition, by providing a magnetic induction path that reduces the leakage magnetism from the large aperture magnetic cylinder to the outside by inducing magnetism, the magnetism incident on the magnetic shield body from the magnetic source through the magnetic induction path, Since it can be guided to a region other than the large opening magnetic cylinder and the magnetism transmitted to the large opening magnetic cylinder can be reduced, the magnetism leaking from the large opening magnetic cylinder can be reduced. Therefore, even when a large opening magnetic cylinder is provided, the magnetism leaking from the large opening magnetic cylinder can be reduced, and by providing the large opening magnetic cylinder, it is possible to reduce the feeling of pressure on the occupant. At the same time, the required magnetic shielding performance can be ensured.
According to the magnetic shield body described in appendix 10, since the support means is formed of a conductive material, an electromagnetic wave shielding effect can be obtained, and even when the magnetism from the magnetic source fluctuates, the variable magnetism Can be reduced by the effect of eddy current.

1, 2, 3 Magnetic shield body 10 Frame 11 Through-hole 20, 20A, 20B Magnetic square tube body 21, 22 Side portion 23 Corner portion 30-32 Notch portion 40 Magnetic guide path 50 Cylindrical shield body 51 Magnetic plate body 52 Plate-shaped shield E1 Application area E2 Reduction target area E3 Shortest area E4 Surrounding area E5 Opposite area

Claims (7)

A magnetic shield body comprising a plurality of magnetic cylinders arranged in parallel with each other through a support means,
From the application region to which the strongest magnetism from the magnetic source is applied among the regions in the magnetic shield body, including the partial magnetic cylinder of the plurality of magnetic cylinders, the magnetic shield body By inducing magnetism in a region other than the reduction target region including the other part of the plurality of magnetic cylinders, which is a reduction target region in which magnetic leakage to the outside is desired to be reduced, Reducing leakage magnetism from the reduction target area to the outside,
Alternatively, a magnetic plate shape that is an application region to which the strongest magnetism from a magnetic source is applied among the regions in the magnetic shield body and is arranged non-parallel to the axial direction of the plurality of magnetic cylinders A reduction target region including a magnetic cylinder part of the plurality of magnetic cylinders in which the magnetic leakage to the outside is reduced in the magnetic shield body from the application region including a part of the body. By reducing the leakage magnetism from the reduction target area to the outside by inducing magnetism in an area other than the area,
With a magnetic taxiway ,
The relative permeability of a part of the plurality of magnetic cylinders, the relative permeability along the z direction being the cylinder axis direction of the magnetic cylinder, or orthogonal to the z direction. The magnetic induction path is formed by setting at least one of the relative permeability along the direction to be different from the relative permeability in the same direction in the other magnetic cylinder among the plurality of magnetic cylinders. And
The magnetic cylinder is a cutout part formed by cutting out only a part of the outer peripheral part of the magnetic cylinder, and is a cutout part formed on the side surface and the corner of the magnetic cylinder. There is a notch portion for reducing the relative permeability along the direction perpendicular to the notch portion from the relative permeability in the same direction in the magnetic rectangular cylinder of the same shape without the notch portion, The relative permeability of the magnetic cylinder was adjusted by providing a notch formed with a length and a width corresponding to a required reduction amount of the relative permeability,
Magnetic shield body. The magnetic cylinder is a square cylinder-shaped magnetic square cylinder,
Of the relative permeability of the part of the magnetic cylinders, the relative permeability along the z direction, the ratio along the x direction that is perpendicular to the z direction and perpendicular to one side surface of the magnetic cylinder. At least one of the magnetic permeability and the relative magnetic permeability along the y direction orthogonal to the z direction and the x direction is different from the relative magnetic permeability along the same direction in the other magnetic cylinder. By forming the magnetic induction path,
The magnetic shield body according to claim 1. By making the relative permeability of the magnetic cylinder disposed in the shortest area on the shortest path from the application area to the reduction target area smaller than the relative permeability of other magnetic cylinders, other than the shortest area The magnetic induction path was formed in the area of
The magnetic shield body according to claim 1 or 2. The relative magnetic permeability along the z-direction of the magnetic cylinder included in the reduction target area is the ratio along the same direction in the other magnetic cylinders arranged in the peripheral area around the reduction target area By reducing the magnetic permeability, the magnetic induction path was formed in a region other than the surrounding region,
The magnetic shield body as described in any one of Claim 1 to 3. Other relative to the relative permeability along the z direction of the magnetic cylinder included in the reduction target region is included in the opposite region located on the opposite side of the application region across the reduction target region. By increasing the relative permeability along the same direction in the magnetic cylinder, the magnetic induction path was formed in the opposite region,
The magnetic shield body as described in any one of Claim 1 to 4. Of the plurality of magnetic cylinders, some of the magnetic cylinders are formed as large opening magnetic cylinders having larger openings than the other magnetic cylinders,
The reduction target region is a region including the large opening magnetic cylinder,
The magnetic shield body as described in any one of Claim 1 to 5. The support means is formed of a conductive material.
The magnetic shield body as described in any one of Claim 1 to 6.

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