JP2006351598A - Magnetic-shield blind and its linking structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide magnetic-shield blinds which can be connected magnetically via an air gap, and to provide a linking structure of the blinds. <P>SOLUTION: A plurality of magnetic shield blinds 10a, 10b and 10c where a group of magnetic boards 5 whose short sides with rectangular cross-sections crossing a length-wise direction are set to be board thickness are laminated at prescribed board thickness direction intervals (d), so that lengthwise direction center axes C of the respective magnetic boards 5 are arranged in parallel on the same blind face F are vertically arranged in the lengthwise direction of the magnetic boards 5 of the blinds 10a, 10b and 10c through the prescribed air gap W. Magnetic extension boards 11 extending an area of end edge faces 12 are fitted to the lengthwise direction end edges of the magnetic boards 5 of the blinds 10a, 10b and 10c facing the air gap W. The blinds 10a, 10b and 10c in vertical arrangement with the air gap W are magnetically connected by confrontation of the magnetic extension boards 11. It is desirable that the magnetic extension boards 11 are made into a magnetic angle whose cross section is an L shape or a T shape. or a magnetic angle (magnetic clamp) with the cross section of a U shape. Its both end pieces are brought into face contact with the lengthwise direction end edge of the adjacent magnetic board 5, and an intermediate part extends between the length direction end edges. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic shield housing and a connection structure thereof, and more particularly to a magnetic shield housing used in an open shield structure that is permeable to air and light and a connection method thereof.

  In recent semiconductor-related facilities and medical facilities, EB (Electron Beam) exposure equipment, EB lithography, MRI (Magnetic Resonance Imaging) equipment, NMR (Nuclear Magnetic Resonance) equipment The use of strong magnetic devices such as biomagnetic measuring devices using SQUID (Superconducting Quantum Interference Device) has been increasing, and the strong magnetic devices are protected from environmental magnetic noises and operate normally. In order to guarantee and / or protect the surrounding people and equipment from the magnetic effects of strong magnetic devices, there is an increasing demand for magnetic shield rooms. As disclosed in, for example, Patent Document 1, a conventional magnetic shield room is a microscopic material obtained by crystallizing a directional electrical steel sheet, non-oriented electrical steel sheet, permalloy, soft magnetic steel sheet, amorphous, liquid quenching ribbon with high magnetic permeability. The structure is based on a structure (hereinafter also referred to as a hermetically sealed structure) in which a wall surface of a space to be shielded is covered with a magnetic material plate such as a crystalline magnetic material (hereinafter also referred to as a magnetic plate). However, the hermetic shield structure has a problem in that the shielding performance as expected from the material characteristics of the magnetic plate cannot be obtained easily and there is no air or light permeability.

  On the other hand, the present inventors have developed a magnetic shield structure with a gap (hereinafter sometimes referred to as an open type shield structure) using a group of magnetic plates arranged in a bowl shape (hereinafter referred to as a magnetic shield case). And disclosed in Patent Document 2 and Patent Document 3. The open type shield structure of Patent Document 2 will be described with reference to FIG. 10 to the extent necessary for understanding the present invention. FIG. 10A shows an example of eight strip-shaped magnetic plates 5 having a thickness of 0.35 mm, a width of 25 mm, and a length of 300 mm, for example, such that their longitudinal central axes C are arranged substantially in parallel on the same saddle surface F. An example of the magnetic shield housing 6 formed by being overlapped with a distance d = 30 mm in the thickness direction is shown. For example, the ratio (Sm · μs) of the product (Sm · μs) of the cross sectional area Sm of the magnetic plate 5 and the relative permeability μs of the magnetic plate 5 to the cross sectional area Sa of the interval d in the direction perpendicular to the length direction of each magnetic plate 5 For example, (Sm · μs) / Sa> 1 is selected so that the magnetic flux density in the interval d is sufficiently smaller than the magnetic flux density in the magnetic plate 5.

  A plurality of magnetic shield housings 6 having a plate thickness direction interval d as shown in FIG. 10A are joined to the edge of the magnetic plate 5 of each housing 6 so that the magnetic properties as shown in FIG. Thus, a continuous row 8 of magnetic shield housings 6 (hereinafter sometimes referred to as a row housing) 8 can be formed. In the figure, four casings 6a, 6b, 6c, and 6d are joined in a column by overlapping the edges of the corresponding magnetic plates 5, and the unjoined edges of the magnetic plate 5 on one end side are also connected. This is an example in which a magnetically closed annular columnar housing 8 (internal volume 280 mm × 280 mm × 280 mm) is formed by overlapping and joining with the unjoined edge of the corresponding magnetic plate 5 on the end side. Reference numeral 9 in the drawing indicates an overlapping portion of the edge of the magnetic plate 5.

10B is installed at the center of the annular coil (for example, Helmholtz coil) L shown in FIG. 12A, and the unidirectional magnetic field M of 10 to 100 μT is provided at the center of the coil L. And the magnetic flux density B is measured by a magnetic sensor 34 (for example, a gauss meter) inside the columnar housing 8, and the shield coefficient S of the columnar housing 8 (= the magnetic flux density B ₀ when there is no shield / the shield is The magnetic flux density B) in some cases was calculated. For comparison, a cubic sealed magnetic shield 31 as shown in FIG. 10C is obtained by four rectangular magnetic plates 32a, 32b, 32c and 32d having a thickness of 0.35 mm and a width and length of 280 mm × 280 mm. Was similarly installed in the center of the annular coil L, and the shield coefficient S of the hermetic shield 31 was calculated. The weight of the magnetic material used for the sealed shield body 31 in FIG. 10C is substantially the same as the weight of the magnetic material used in the row housing 8 in FIG.

  Table 1 shows the shield coefficient S of the columnar housing 8 and the sealed shield body 31 with respect to the unidirectional magnetic field M of 10 μT, 50 μT, and 100 μT. Table 1 shows that the shield coefficient S of the columnar housing 8 with respect to the unidirectional magnetic field M of 10 to 100 μT is about 2 to 3 times higher than that of the sealed shield body 31. That is, it can be said that the row-like housing 8 in FIG. 10B has an open shield structure that has less magnetic flux leakage and has higher shielding performance and air permeability and translucency than the sealed shield structure. In addition, there is an advantage that an advanced magnetic shield structure can be constructed economically and efficiently by reducing the magnetic material necessary for obtaining the required shield performance as compared with the hermetic shield.

  When the row-shaped housing 8 of FIG. 10 (B) is applied to an actual magnetic shield room, as shown in FIG. 11 (A), for example, a magnetic plate in which a plurality of magnetic thin plates 7 having a thickness of 0.35 mm are superimposed. 5 is used. The magnetic plate 5 in the illustrated example has a cross-sectional area Sm enlarged by superimposition of the magnetic thin plates 7 and irregularities are formed on the end surfaces in the longitudinal direction with the edges of the magnetic thin plates 7 being uneven. In order to form the row-shaped housing 8 having high shielding performance, it is important to suppress the leakage of magnetic flux from the joint portion of the magnetic plate 5 to a small level. However, as shown in FIG. By joining by fitting, the magnetic flux leakage from the joining part of the magnetic plate 5 can be suppressed extremely small. Further, the magnetic plate 5 with concave and convex end faces can be joined not only in a right angle direction as shown in the illustrated example but also in a straight line shape or an arbitrary angle according to the shape of the shield target surface of the shield room.

JP-A-9-162585 Japanese Patent No. 3633475 International Publication No. 2004/084603 Pamphlet Architectural Institute of Japan “Environmental Magnetic Field Measurement Techniques—In-Situ Measurement Examples” Maruzen Co., Ltd., July 15, 1998, 1st Edition, pp.19-22

  However, the columnar housing 8 in FIG. 10B improves the shielding performance by forming a magnetically closed magnetic circuit surrounding the shield target space. However, if the columnar housing 8 is provided with an opening / closing part. There is a problem that a closed magnetic circuit cannot be formed. The magnetic shield room is often provided with an opening / closing part such as a door or a window, and a gap W for opening / closing needs to be provided around the opening / closing part. When a discontinuous part is generated in the magnetic circuit due to the air gap W, magnetic flux leaks from the discontinuous part and the shielding performance is deteriorated. In order to apply the open type shield structure to an actual magnetic shield room, it is necessary to take measures to reduce the leakage of magnetic flux from the gap W around the opening / closing part.

  FIG. 13 shows an example of a magnetic shield room 41 developed by the present inventors using the row of enclosures 8 (see Japanese Patent Application No. 2004-332380). In the illustrated magnetic shield room 41, magnetic shield housings 6 are arranged on four sides of the magnetic shield walls 42a, 42b, 42c, 42d, and each housing 6 is joined by column members 44 at four corners, and specific shield walls are provided. An opening is provided in 42a. A portal frame 45 comprising a pair of vertical frame 45a and horizontal frame 45b is provided at the periphery of the opening, and the magnetic shield door 43 is installed inside the frame 45. The magnetic shield door 43 includes a group of fixed shield plates 46a and movable shield plates 46b arranged in a bowl shape corresponding to the group of magnetic plates 5 on the adjacent shield wall 42a, and a movable mechanism 48 that moves each movable shield plate 46b. Have. Openings W1 and W2 for opening and closing are provided between the portal frame 45 and the magnetic shield door 43, and through holes (not shown) for inserting the movable shield plate 46b into the vertical frame 45a of the portal frame 45 are shown. Z). When the door is closed, each movable shield plate 46b is inserted into the through hole and joined to each magnetic plate 5 of the adjacent shield wall 42a by the movable mechanism 48, and when the door is opened, the movable shield plate 46b is connected to each magnet of the adjacent shield wall 42a. Separate from plate 5.

  The magnetic shield door 43 in FIG. 13 joins the movable shield plate 46b to the magnetic plate 5 of the adjacent magnetic shield wall 42a when the door is closed, and between the magnetic shield door 43 and the magnetic shield walls 42a, 42b, 42c, 42d. Since a closed magnetic circuit is formed, magnetic flux leakage from the air gaps W1 and W2 around the door can be suppressed to a small level. However, since the magnetic shield door 43 in the illustrated example moves the movable shield plate 46b by using a complicated movable mechanism 48, there are problems that the manufacturing cost increases, the weight becomes very large, and the translucency decreases. Development of technology to magnetically connect the magnetic shield wall 42a and the magnetic shield door 43 without using a movable mechanism in order to take advantage of the open type shield structure that can economically construct a highly transparent magnetic shield structure Is desired.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic shield housing that can be magnetically coupled through a gap and a connection structure thereof.

  The inventor paid attention to the area of the edge in the longitudinal direction of each magnetic body 5 of the magnetic shield housing 6. As described above, since the casing 6 has a larger plate thickness direction interval d than the thickness of the magnetic plate 5, the plurality of casings 6 are arranged in the length direction of the magnetic body 5 through the gaps W as shown in FIG. 13. Are arranged in tandem, the cross-sectional area of the magnetic plate 5 at the edge of each opposing housing 6 is smaller than the cross-sectional area of the interval d. The inventor suppresses magnetic flux leakage from the gap W between the opposing housings 6 by making the cross-sectional area of the magnetic plate 5 at the edge of the housing 6 larger than the cross-sectional area of the interval d, It was experimentally found that the housing 6 can be magnetically coupled through the gap W (see Experimental Example 1 described later). The present invention has been completed based on this finding.

  Referring to the embodiment of FIG. 1, a magnetic shield housing 10 according to the present invention includes a group of magnetic plates 5 having a short side of a rectangular cross section that intersects the length direction as a plate thickness. Stacked in a bowl shape with a predetermined thickness direction interval d so that the central axes C are arranged in parallel on the same bowl surface F, the area of the edge face 12 is set at one edge or both edges in the length direction of each magnetic plate 5. A magnetic expansion plate 11 extending in the thickness direction is attached.

  Referring to the embodiment of FIG. 1, the connecting structure of magnetic shield housings according to the present invention is a group of magnetic plates 5 each having a short side of a rectangular cross section that intersects the length direction. A plurality of magnetic shield housings 10a, 10b, 10c, which are stacked at a predetermined thickness direction interval d so that the central axis C in the length direction is arranged in parallel on the same housing surface F, are magnetic plates of the housings 10a, 10b, 10c. 5 are arranged in a row in a longitudinal direction through a predetermined gap W, and the area of the edge surface 12 is defined in the thickness direction at the edge in the length direction of the magnetic plate 5 of each of the housings 10a, 10b, 10c facing the gap W. A magnetic expansion plate 11 is attached to the magnetic expansion plate 11, and the casings 10a, 10b, 10c arranged in a column with a gap W are magnetically coupled to each other by facing the magnetic expansion plate 11.

  For example, as shown in FIGS. 2 (B) and 2 (C), the magnetic expansion plate 11 has one piece a in surface contact with the longitudinal edge of the magnetic plate 5 and the other piece b extending from the edge in the plate thickness direction. A magnetic angle 11a having an L-shaped cross section extending or as shown in FIG. 4D, the central leg a is in surface contact with the longitudinal edge of the magnetic plate 5, and the top ends b are plate thicknesses from the edge. A magnetic angle 11b having a T-shaped cross section extending on both sides in the direction can be obtained.

  Preferably, as shown in FIG. 3 (A), the magnetic extension plate 11 has both end pieces a in surface contact with the longitudinal edge of the adjacent magnetic plate 5 and the intermediate part b is the longitudinal edge. A magnetic angle 11c having a U-shaped cross section extending therebetween is used. More preferably, as shown in FIG. 7 (A), a magnetic rod 16 or a magnetic frame 17 is provided which is in surface contact with the end face 12 extended by each magnetic extension plate 11 and connects the end faces 12 to each other. .

  The magnetic shield housing 10 of the present invention is formed by laminating a group of magnetic plates 5 having a short side of a rectangular cross section with a thickness in the thickness direction at a predetermined interval d, and laminating the magnetic plates 5 in the length direction. Since the magnetic expansion plate 11 that expands the area of the end surface 12 in the thickness direction is attached to one end edge or both end edges, the following remarkable effects can be obtained.

(A) By expanding the area of the lengthwise edge surface 12 of the magnetic plate 5, the cross-sectional area of the magnetic plate 5 at the lengthwise edge of the housing 10 is made larger than the cross-sectional area of the interval d. be able to.
(B) When the casings 10 are arranged in tandem through the gap W in the length direction of the magnetic plate 5, a large opposing area of the magnetic plate 5 is secured, and magnetic flux leakage from the gap W is suppressed to be small. Can be magnetically coupled.
(C) If the gap W between the casings 10 is 5 mm or less, the magnetic flux leakage from the gap W can be suppressed to 0.5 mT or less.
(D) Since only the edge surface 12 of the magnetic body 5 is expanded in the plate thickness direction, high translucency of the housing 10 can be ensured by the plate thickness interval d in the portion other than the edge.
(E) Since the casings 10 arranged in tandem via the gap W can be magnetically coupled, it can be used when constructing an open type shield structure having an opening / closing part such as a door or a window.

  FIG. 1 shows an embodiment of a magnetic shield room 1 constructed using a magnetic shield housing 10 of the present invention. In the illustrated magnetic shield room 1, magnetic shield housings 10a, 10b, and 10c of the present invention are arranged in tandem on one wall 2a via gaps W1 and W2, and the other three walls 2b, 2c, and 2d are arranged. The magnetic shield housings 6 shown in FIG. 10 are joined together in a row, and the edges of the housings 10a and 10c not facing the gaps W1 and W2 are joined in rows with the housings 6 of the walls 2b and 2d. It is a thing. Hereinafter, the present invention will be described with reference to FIG. 1, but the magnetic shield housing 10 of the present invention is not limited to application to the shield room 1, and can be applied to any shield target surface. As shown in FIG. 7D, the magnetic shield housing 10 of the present invention can be combined with a magnetic plate 32 of a conventional sealed magnetic shield to form a shield room or a shield surface.

  The magnetic shield housings 10a, 10b, and 10c in the illustrated example have a rectangular cross section that intersects with the length direction, like the magnetic shield housing 6 in FIG. A plurality of strip-shaped magnetic plates 5 each having a plate width are stacked at a required interval d in the plate thickness direction so that the longitudinal center axes C of the magnetic plates 5 are arranged in parallel on the same saddle surface F. 5, the magnetic expansion plate 11 is attached to one end edge or both end edges in the length direction facing the gaps W1 and W2, and the area of the edge surface 12 is expanded in the plate thickness direction. It is desirable that the magnetic plates 5 constituting the casing 10 have the same width and length. If necessary, the central axis C of each magnetic plate 5 may be a curved line, and the flange surface F may be a curved surface. Each magnetic plate 5 only needs to have the central axis C on the same saddle surface F, and the angular position around the central axis C may be different for each magnetic plate 5.

  The thickness d interval of the magnetic plates 5 of the respective housings 10a, 10b, 10c is determined by the cross sectional area Sm of the magnetic plate 5 and the magnetic plate 5 with respect to the cross sectional area Sa of the interval d according to the shielding performance given to the respective housings 10. The ratio (Sm · μs / Sa) of the product (Sm · μs) with the relative permeability μs is selected to be greater than 1. By setting (Sm · μs / Sa)> 1, the easiness of magnetic flux in the magnetic plate 5 (permeance of the magnetic plate) is made larger than the easiness of magnetic flux in the interval d (permeance of the interval), and the interval The magnetic flux density at d can be reduced, and the shield performance can be imparted to the housing 10. Further, by increasing the thickness direction interval d of the magnetic plate 5 to be larger than the width of the magnetic plate 5 (long side of the rectangular cross section), the magnetic body 5 can be saved as compared with the hermetic shield (see FIG. 10C). In addition, high translucency can be obtained. In order to obtain high shielding performance and high translucency at the same time, it is desirable that both (Sm · μs / Sa) and the distance d be sufficiently large. The thicknesses d of the magnetic plates 5 of the respective housings 10a need not be the same in the thickness direction, and the intervals d may be different depending on the positions of the magnetic plates 5.

  For example, as shown in FIGS. 2B and 2C, the magnetic expansion plate 11 attached to the edge of the magnetic plate 5 of each housing 10a, 10b, 10c can be a magnetic angle 11a having an L-shaped cross section. . In FIG. 5B, one piece a of the L-shaped magnetic angle 11a is placed on the surface of the edge of the magnetic plate 5 and brought into surface contact, and the other piece b is extended from the edge in the thickness direction of the magnetic plate 5. The area of the edge surface 12 is expanded. FIG. 11C shows a magnetic plate 5 with concave and convex end surfaces (see FIG. 11) in which a plurality of magnetic thin plates 7 are superimposed, and a piece a of L-shaped magnetic angle 11a is fitted to the concave and convex end surfaces of the magnetic plate 5. The other end b is extended from the end edge in the plate thickness direction. The width of the L-shaped magnetic angle 11a is preferably matched with the width of the magnetic plate 5 (long side of the rectangular cross section).

  By bringing the piece a of the magnetic angle 11a into surface contact with the edge of the magnetic plate 5, the leakage of magnetic flux from the joint between the magnetic plate 5 and the magnetic angle 11a can be kept small. Further, by fitting the magnetic angle 11a with the concave and convex end face of the magnetic plate 5, it can be expected that the angle 11a and the magnetic plate 5 are brought into surface contact with each other to further reduce the leakage of magnetic flux from the joint. The length of the other piece b of the magnetic angle 11 can be appropriately selected. However, for example, the length can be substantially the same as the distance d so that the area of the end face 12 of the magnetic plate 5 is as large as possible.

  Further, the magnetic expansion plate 11 has a T-shaped magnetic angle 11b as shown in FIG. 2 (D), its central leg a is brought into surface contact with the edge of the magnetic plate 5, and both ends b of the top portion from the edge. The area of the edge surface 12 of the magnetic plate 5 can be expanded by extending both sides in the plate thickness direction. The width of the T-shaped magnetic angle 11b is preferably matched with the width of the magnetic plate 5. In the illustrated example, a pair of L-shaped angles 11a are combined back to back to form a T-shaped magnetic angle 11b, and the center leg a is fitted to the uneven end surface of the magnetic plate 5 and brought into surface contact with the magnetic plate 5. . For example, the area of the edge surface 12 of the magnetic plate 5 can be maximized by using a T-shaped magnetic angle 11b in which the length of the top end b is about ½ of the distance d.

  Desirably, as shown in FIG. 3 (A), the magnetic expansion plate 11 has a U-shaped magnetic cross section (sharp shape) magnetic angle 11c, and both end pieces a face the edge in the longitudinal direction of the adjacent magnetic plate 5, respectively. The intermediate portion d is extended between the edges of the adjacent magnetic plates 5 to expand the area of the edge surface 12 of the magnetic plate 5. When the L-shaped or T-shaped magnetic angles 11a and 11b are used, a gap or a joint is formed between the edge surfaces 12 of the adjacent magnetic plates 5 as shown in FIG. 1, but the U-shaped magnetic angle 11c is used. As a result, the end surface 12 of each magnetic plate 5 can be integrated to form an end surface 12 having no gap or joint. The width of the U-shaped magnetic angle 11c is desirably matched with the width of the magnetic plate 5.

  As shown in FIG. 1, the magnetic shield housings 10a, 10b, and 10c are arranged in tandem through the air gaps W1 and W2, so that the housing 10b having the air gaps W1 and W2 around them is used as the opening / closing part of the magnetic shield room 1. be able to. FIG. 7A shows an embodiment in which the housing 10b is an opening / closing door. In this embodiment, magnetic flanges 16 are provided on both ends of the casing 10b facing the gaps W1 and W2 so as to make contact with the extended edge surfaces 12 of the magnetic extension plates 11 and connect the edge surfaces 12 to each other. In addition, a magnetic frame 17 is provided on the end edges of the housings 10a and 10c facing the gaps W1 and W2 to connect the extended end face surfaces 12 to each other by surface contact. Further, the top end of the magnetic frame 17 is magnetically joined to the magnetic beam 18 above the housings 10a and 10c to form a magnetic gate frame, and the bottom end of the gate frame is fixed to the floor 19 to surround the door. A four-sided frame is formed. A gap is interposed between the four-sided frame and the casing 10b, and the casing 10b can be opened and closed by connecting the casing 10b to the adjacent magnetic frame 17 with, for example, a hinge 24.

[Experiment 1]
In order to confirm the shielding performance of the magnetic shield housing 10 of the present invention, the magnetic shield room of FIG. In the experiment, as shown in FIG. 11, a magnetic plate 5 with an uneven end face having a thickness of 6.3 mm and a width of 50 mm, in which 18 magnetic thin plates 7 having a thickness of 0.35 mm are overlapped, is joined to obtain an appropriate length. Six magnetic shield housings 6a, 6b, 6c, 6d, 6e, 6f are produced in the thickness direction with an interval d = 300 mm, and each housing 6a, 6b, 6c, as shown in FIG. 6d, 6e, 6f are joined at the uneven edges of each magnetic plate 5 so as to surround the space to be shielded, or arranged in tandem via the gaps W1, W2, so that the magnetic shield room (frontage 3.6m x depth 2.7m x A height of 1.8 m was formed.

  12B, the L-shaped, T-order or U-shaped magnetic angles 11a, 11b or 11c are placed on the uneven edges facing the gaps W1 and W2 of the magnetic plates 5, respectively. Alternatively, the magnetic shield housings 10a, 10b, and 10c shown in FIG. Magnetic angle 11a, 11b, or 11c, 0.35mm thick, 50mm wide, each piece a, b = 100mm L-shaped angle made of magnetic thin plate overlapped, 0.35mm thick, 50mm wide, both ends a = 3 mm of U-shaped angle made of magnetic thin plate with an intermediate part d = 300 mm was used.

  As shown in FIG. 12B, an annular coil L is installed inside the prototype magnetic shield room, and a direct current of the same level as that of the MRI apparatus is passed through the coil L in the direction of arrow I to form a direct current magnetic field M. The leakage magnetic flux density outside the gap W1 in the shield room 1 was measured by the magnetic sensor 34. The measurement of the leakage magnetic flux density was repeated while moving the magnetic sensor 34 in the direction perpendicular to the rows 6a, 6b, 6c of the row arrangement, and the shielding performance was confirmed from the relationship between the horizontal distance from the gap W1 and the leakage magnetic flux density. First, check the shielding performance of the magnetic shield room with the gaps W1 and W2 between the housings 6a, 6b, and 6c set to W1 = 20mm and W2 = 5.0mm, and then maintain the gap W2 at 5.0mm. However, the shielding performance of the magnetic shield room with the gap W1 of 5.0 mm and 3.0 mm was confirmed.

  FIG. 4 shows the shielding performance of the magnetic shield room with the gap W1 = 20 mm and W2 = 5.0 mm. In the graph A in the figure, when the magnetic angle 10 is not attached to the edge of the magnetic plate 5 of the housings 6a, 6b, 6c (see FIG. 2A), the graph B shows the L-shaped magnetic angle 11a of the magnetic plate 5 When the surface is brought into surface contact (see (B) in the same figure), the graph C is obtained when the L-shaped magnetic angle 11a is fitted to the uneven edge of the magnetic plate 5 (see (C) in the same figure), and the graph D is obtained. When the T-shaped magnetic angle 11b is fitted to the uneven edge of the magnetic plate 5 (see FIG. 4D), the graph E shows the case where the U-shaped magnetic angle 11c is fitted to the uneven edge of the magnetic plate 5. Each of the shielding performances (see FIG. 3A) is represented. For comparison, graph G shows the shielding performance of a shield room (see FIG. 3C) formed by the row housing 8 of FIG. 10B without the gaps W1 and W2.

  From the comparison of the graphs A to E in FIG. 4, by attaching the magnetic angles 11a, 11b, 11c to the end edges of the magnetic shield housings 6a, 6b facing the air gap W1 to expand the area of the end face 12, the air gap W1 It can be seen that the magnetic flux leakage from can be reduced. For example, in an MRI room in a medical institution, it is desired that the external leakage magnetic flux in the MRI room be suppressed to 0.5 mT or less so as not to adversely affect an outdoor pacemaker wearer (see Non-Patent Document 1). The experimental results in FIG. 4 show that the MRI chamber formed by the magnetic shield housing 6 has an air gap W1 of about 20 mm and the end surface 12 of each magnetic body 5 of the housing 6 is not expanded. In order to make the external leakage magnetic flux from the chamber 0.5 mT or less, it is necessary to move away from the housing 6 by about 175 mm (see graph A), but when the end face 12 is expanded by the U-shaped magnetic angle 11c, the separation distance is This shows that it can be shortened to about 125 mm (see graph E). However, in the range where the horizontal separation distance from the housing 6 is 100 mm or less, it is difficult to suppress the leakage magnetic flux from the air gap W1 to 0.5 mT or less only by expanding the end face 12. To further reduce the leakage magnetic flux It is necessary to provide magnetic scales 21 and 22 to be described later in the gap W1 (see graph F).

  FIG. 5 shows the shielding performance of the magnetic shield room with the gap W1 = 5.0 mm and W2 = 5.0 mm, and FIG. 6 shows the shielding performance with the gap W1 = 3.0 mm and W2 = 5.0 mm. The graphs A to E and the graph G in the same figure show the shielding performance in the state where the end face 12 is the same as the graphs A to E and the graph G in FIG. As can be seen from the graphs of FIGS. 5 and 6, if the size of the air gap W1 is about 5 to 3 mm, the leakage magnetic flux is expanded by the extension of the end face 12 even when the horizontal separation distance from the housing 6 is 100 mm or less. The magnetic flux leakage from the gap W can be effectively suppressed. Graph F in FIG. 6 shows the shielding performance in a state in which magnetic scales 21 and 22 to be described later are provided in the gap W1, but the graph E and the graph F attached with the U-shaped magnetic angle 11c almost overlap with each other. When the size of W1 is about 3 mm, it can be seen that the leakage of magnetic flux from the air gap W1 can be suppressed to the same level as when the magnetic weatherings 21 and 22 are provided in the air gap W1 by expanding the edge surface 12.

  That is, according to the magnetic shield casing 10 of the present invention, even if there is a gap W between the casings 10, the effective area of the lengthwise edge surface 12 of each magnetic plate 5 of the casing 10 is reduced. By expanding, the magnetic flux leakage from the air gap W can be reduced. If the size of the air gap W is about 5 to 3 mm, the magnetic flux leakage from the air gap W is suppressed to 0.5 mT or less and the The body 10 can be magnetically coupled. Further, since only the edge surface 12 of the magnetic body 5 is expanded in the plate thickness direction, and the plate thickness interval d of the portion other than the edge is kept sufficiently large, high translucency equivalent to that of the housing 6 in FIG. It can be secured. Furthermore, magnetic flux leakage from the gap W can be suppressed economically and efficiently simply by attaching the magnetic expansion plate 11 without using a movable mechanism as in the embodiment of FIG. Therefore, effective use can be expected when an open shield structure is applied to a magnetic shield room having an opening / closing part such as a door or a window.

  Thus, it is possible to provide the “magnetic shield housing that can be magnetically coupled through the air gap and its connecting structure”, which is an object of the present invention.

  FIGS. 7B and 7C show an embodiment in which a magnetic cover 21 or 22 is provided to cover the gap W1 between the magnetic shield housings 10a and 10b arranged in a column from the direction perpendicular to the column direction. As described above, the present invention can suppress magnetic flux leakage from the gap W by sufficiently expanding the end face 12 of each magnetic plate 5 of the housing 10, but the gap W is relatively large and the end face 12 When the leakage magnetic flux cannot be made sufficiently small only by the expansion of, it is effective to provide the magnetic struts 21 and 22 in the gap W. FIG. 5B shows an embodiment in which the entire area of the air gap W1 is covered with a belt-shaped magnetic strip 21 having the same height as the height of the magnetic shield housing 10 (stacking height of the magnetic plates 5), and FIG. This is an embodiment in which the portions of the gap W1 facing the magnetic expansion plate 11 are discretely covered with chip-shaped magnetic strips 22 having a size corresponding to the expansion edge surface 12 of the expansion plate 11.

  Since the magnetic shield housing 10 of the present invention is magnetically coupled via the extended edge surface 12 of the magnetic expansion plate 11, it is considered that magnetic flux leakage from the air gap W1 mainly occurs from the extended edge surface 12. Therefore, even if the entire area of the gap W is not covered with the belt-shaped magnetic strips 21, it is expected that the magnetic flux leakage from the gap W can be sufficiently suppressed by preferentially covering the portion where the magnetic flux leakage is large with the chip-shaped magnetic strips 22. . If the magnetic flux leakage from the air gap W can be sufficiently suppressed by the chip-shaped magnetic strips 22, the magnetic material can be saved as compared with the case where the strip-shaped magnetic strips 21 are used. When the casing 10b is used as an open / close door as shown in FIG. 7A, the magnetic weather covers 21 and 22 can be installed on the door tips and the four-sided frame of the door.

[Experiment 2]
In order to confirm the shielding performance by the magnetic weathering 21, as shown in FIG. 7 (B), the gap W1 of the magnetic shield room used in the experimental example 1 is covered with the belt-shaped magnetic weathering 21 and shielded by the same method as in the experimental example 1. Performance was measured. The shield performance in the case where the magnetic weathering 21 is provided is shown in a graph G in FIGS. 4 to 6 (see FIG. 3B). As can be seen from the graph G in FIGS. 4 and 5, by installing the magnetic cover 21, the magnetic flux leakage from the air gap W1 can be made sufficiently small, and the horizontal separation distance from the air gap W1 at which the leakage magnetic flux is 0.5 mT or less is 75 mm. Can be as short as However, when the size of the air gap W1 is about 3 mm, the magnetic flux from the air gap W1 is increased by increasing the end surface 12 of each magnetic plate 5 of the magnetic shield housing 10 as described above with reference to FIG. Leakage can be minimized and the installation of the magnetic weathering 21 can be omitted.

[Experiment 3]
Next, in order to confirm the shielding performance by the chip-shaped magnetic strip 22, the gap W 1 of the magnetic shield room having the gap W 1 = 20 mm used in Experimental Example 1 is covered with the strip-shaped magnetic strip 21 and the chip-shaped magnetic strip 21. The shield performance was measured using the same method as above, and the shield performance was compared. In this experiment, as shown in FIG. 8A, the magnetic shields 21 and 22 are provided on the arrival side of the magnetic field to be shielded (inside the magnetic shield room) of the magnetic shield housing 10 with a gap Q = 5.0 mm. Covered the gap W1. The shield performance of the chip-shaped magnetic strip 22 is shown in graph 1 of FIG. 9, and the shield performance of the strip-shaped magnetic strip 21 is shown in graph 2 of FIG. From comparison between graphs 1 and 2, the chip-shaped magnetic strips 22 can provide almost the same shielding performance as that of the strip-shaped magnetic strips 21. In the magnetic shield housing 10 of the present invention, the chip-shaped magnetic strips 22 can eliminate the gap W. It was confirmed that the leakage of magnetic flux can be controlled economically and efficiently.

[Experimental Example 4]
Further, in order to confirm the change in the shield performance depending on the installation position of the magnetic weathering 21, as shown in FIGS. 8B and 8C, the side opposite to the arrival side of the magnetic field to be shielded of the magnetic shield housing 10 (magnetic shield) Measure the shielding performance when the gap W1 is covered by the strip-shaped magnetic strips 21 arranged outside the room with a gap Q = 5.0mm, and the shielding performance when the both sides of the gap W1 are covered by the strip-shaped magnetic strips 21. did. The shield performance when covering the gap W1 from the outside of the magnetic shield room is shown in graph 3 of FIG. 9, and the shield performance when covering both sides of the gap W1 is shown in graph 4 of FIG. Since the shielding performance of Graph 3 is considerably superior to that of Graph 2, the knowledge that it is effective to install the strip-shaped magnetic weathering 21 in the gap W outside the magnetic shield room is obtained. It was. Further, since the graph 3 and the graph 4 have substantially the same shielding performance, it can be seen that it is sufficient that the belt-shaped magnetic strip 21 is installed outside the gap W.

  The reason why it is effective to install the magnetic cover 21 outside the magnetic shield room in this experiment is that the magnetic field lines generated from the coil L installed at the center of the magnetic shield room tend to bulge outward. This is presumably because the leakage magnetic flux from the magnetic shield housing 10 also tends to bulge outward. Although the shielding performance of FIG. 9 is due to the strip-shaped magnetic strips 21, it can be considered from the results of Experimental Example 3 that it is effective to install the chip-shaped magnetic strips 21 outside the magnetic shield room. That is, in the magnetic shield housing 10 of the present invention, the magnetic flux leakage from the air gap W is economically and efficiently suppressed by mainly covering the outside of the air gap W where the magnetic flux leakage is large by the chip-shaped magnetic strips 22. I can expect that.

It is explanatory drawing of the Example of the magnetic shield room using the magnetic shield housing of this invention. It is explanatory drawing of an example of the magnetic expansion board attached to a magnetic shield housing. It is explanatory drawing of the other example of the magnetic expansion board attached to a magnetic shield housing. It is an experimental result which shows the shielding performance of the magnetic shielding housing of this invention connected via the space | gap 20mm. It is an experimental result which shows the shielding performance of the magnetic shielding housing of this invention connected via the space | gap 5mm. It is an experimental result which shows the shielding performance of the magnetic shield housing of the present invention connected through a gap of 3 mm. It is explanatory drawing of the magnetic shielding housing of this invention which installed the magnetic weathering in the space | gap. It is explanatory drawing of the installation method of the magnetic weathering with respect to a space | gap. It is an experimental result which shows the shielding performance of the magnetic shielding housing of this invention which installed the magnetic weathering in the space | gap. It is explanatory drawing of the open type shield structure using the conventional magnetic shield housing. It is explanatory drawing of an example of the magnetic board which comprises a magnetic shield housing. It is explanatory drawing of the shield performance measuring method of a magnetic shield housing. It is explanatory drawing of the conventional magnetic shield room using a magnetic shield housing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Magnetic shield room 2 ... Magnetic shield wall 3 ... Magnetic shield opening / closing part 5 ... Magnetic material board (magnetic board)
6 ... Magnetic shield housing 7 ... Magnetic material thin plate (magnetic thin plate)
8 ... Linear housing 9 ... Overlapping part
10, 10a, 10b ... Magnetic shield housing 11 ... Magnetic expansion plate
11a ... Magnetic angle with L-shaped cross section 11b ... Magnetic angle with T-shaped cross section
11c… Magnetic angle with U-shaped cross section
12 ... Edge 16 ... Magnetic cage
17 ... Magnetic frame 18 ... Magnetic beam
19… Floor 21… Magnetic cover
22 ... chip-shaped magnetic cover 24 ... hinge
31 ... Sealed magnetic shield body 32 ... Square magnetic plate
34… Magnetic sensor 41… Magnetic shield room
42… Magnetic shield wall 43… Magnetic shield door
44: Column material 45, 45a, 45b ... Frame
46, 46a, 46b ... Magnetic shield plate 48 ... Movable mechanism a, b ... Length of angle W ... Gap R ... Depth of unevenness on edge of material plate C ... Center axis F in the length direction of material plate ... Rough surface d ... Thickness direction interval of material plate I ... Current L ... Current carrier (coil)
M ... Magnetic field S ... Shielding factor H ... Magnetic weathering position P ... Magnetic weathering width Q ... Gap between magnetic shield housings arranged in tandem and magnetic weathering

Claims (12)

  A group of magnetic plates whose thickness is the short side of a rectangular cross section that intersects the length direction is formed in a bowl shape at predetermined intervals in the thickness direction so that the central axes in the length direction of each magnetic plate are arranged in parallel on the same saddle surface. A magnetic shield housing that is laminated and attached to one end edge or both end edges in the length direction of each magnetic plate with a magnetic expansion plate that expands the area of the end face surface in the plate thickness direction.   2. The magnetic shield housing according to claim 1, wherein the magnetic extension plate has an L-shaped cross section in which one piece is in surface contact with the longitudinal edge of the magnetic plate and the other piece extends from the edge in the plate thickness direction. Magnetic shield housing.   2. The magnetic shield housing according to claim 1, wherein the magnetic expansion plate has a T-shaped cross section in which a central leg portion is in surface contact with a longitudinal edge of the magnetic plate and both ends of the top portion extend from the edge to both sides in the plate thickness direction. Magnetic shield housing as a magnetic angle.   2. The magnetic shield housing according to claim 1, wherein both ends of the magnetic expansion plate are in surface contact with the longitudinal edges of the adjacent magnetic plates, and an intermediate portion extends between the longitudinal edges. Magnetic shield housing with a U-shaped magnetic angle.   5. The magnetic shield housing according to claim 1, further comprising a magnetic rod or a magnetic frame that is in surface contact with the edge surfaces expanded by the respective magnetic expansion plates and connects the edge surfaces to each other. Magnetic shield housing.   A magnetic group consisting of a group of magnetic plates whose thickness is the short side of a rectangular cross-section that intersects the length direction, with the lengthwise central axes aligned in parallel on the same surface, with a predetermined thickness direction interval. A plurality of shield housings are arranged in tandem in the length direction of the magnetic plate of each housing via a predetermined gap, and the area of the edge surface is defined on the edge in the length direction of the magnetic plate of each housing facing the gap. A connecting structure of magnetic shield housings, in which magnetic expansion plates extending in the thickness direction are attached, and the vertically arranged housings with gaps are magnetically coupled by facing the magnetic expansion plates.   7. The connecting structure according to claim 6, wherein the magnetic expansion plate is formed as a magnetic angle having an L-shaped cross section in which one piece is in surface contact with the longitudinal edge of the magnetic plate and the other piece extends from the edge in the plate thickness direction. Magnetic shield housing connection structure.   7. The connecting structure according to claim 6, wherein the magnetic extension plate is formed of a T-shaped magnetic section in which a central leg portion is in surface contact with a longitudinal edge of the magnetic plate and both top ends extend from the edge to both sides in the plate thickness direction. Connecting structure of magnetic shield housing as an angle.   7. The connection structure according to claim 6, wherein both ends of the magnetic expansion plate are in surface contact with lengthwise edges of adjacent magnetic plates of the housing, and an intermediate portion extends between the lengthwise edges. Connecting structure of magnetic shield housings as a U-shaped magnetic angle.   The connection structure according to any one of claims 6 to 9, wherein a magnetic ridge or a magnetic frame is provided that is in surface contact with the end edge surfaces expanded by the magnetic extension plates of the casing and connects the end edge surfaces to each other. A connecting structure of magnetic shield casings, wherein the gap-arranged casings with gaps are magnetically coupled by facing the magnetic casing or the magnetic frame.   11. The magnetic shield housing according to claim 6, wherein magnetic shields are provided to cover the gaps between the cascade-arranged housings from one side or both sides in a direction perpendicular to the longitudinal direction via a required gap. Connection structure.   12. The connection structure according to claim 11, wherein the magnetic cover has a size corresponding to the extended end face of the magnetic extension plate and is discretely provided in a space where the extended end face faces. Construction.