JP2011165917A - Magnetic shield box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic shield box, capable of preventing a penetrating external noise from reaching an internal object, even though an introduction opening for wirings or the like as invading ports of the external noise exist, and capable of minimizing effects of external magnetic field. <P>SOLUTION: The magnetic shield box for preventing the invasion of external magnetism or electromagnetic wave from entering inside includes a first shield space surrounded by a magnetic shield material, a second shield space partitioned by a partitioning member mounted in the first shield space and housing the object, a third shield space to which internal wirings are introduced, at least one external communication hole for communicating an outside of the magnetic shield box and the third shield space, and at least one internal communication hole for communicating the second shield space and the third shield space to the partitioning member. The internal communication hole does not overlap the position where an opening shape of the external communication hole is linearly extended along the communication direction of the external communication hole. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnetic shield box.

  Conventionally, when an electronic device such as a computer unit is mounted on a mechanical device or an automobile, in order to protect the electronic device from a magnetic line of force that becomes external noise, a method of blocking the external noise by storing it in a metal box container has been taken. (Patent Document 1).

  However, precise control is required by recent precision electronic devices, and it is required to protect and shield even a slight external noise. A magnetic shield box having a double structure has been proposed as a means for effectively shielding finer external noise (Patent Document 2).

JP 2002-141690 A JP 2008-218729 A

  However, with the configuration of Patent Document 2 described above, even if it is effective for shielding external noise in the double structure portion, it is effective against the penetration of an external magnetic field from the openings provided in the inner wall and the outer wall. It was not an effective means. Furthermore, the double structure increases the weight, and is not suitable as a storage box for a small device that is particularly required to be light.

  Therefore, even though it has an introduction hole (opening) such as a wiring that becomes an entrance for external noise, even if it has a simple structure, the external nozzle that has entered does not reach the internal object and is affected by the external magnetic field. Provide a magnetic shield box that minimizes

  The present invention can be realized as the following forms or application examples so as to solve at least one of the above-described problems.

  Application Example 1 A magnetic shield box of this application example is a magnetic shield box that prevents external magnetism or electromagnetic waves from entering inside, and includes a first shield space surrounded by a magnetic shield material and the first shield space. A second shield space for storing an object and a third shield space into which an internal wiring is introduced, which are separated by a partition member placed on the outside, and communicate with the outside of the magnetic shield box and the third shield space At least one external communication hole, and at least one internal communication hole communicating with the partition member between the second shield space and the third shield space, along the communication direction of the external communication hole Thus, the internal communication hole does not overlap with an extension obtained by linearly extending the opening shape of the external communication hole.

  According to the application example described above, the location of the internal communication hole is not within the projection range of the external communication hole serving as an introduction hole for the wiring from the outside, in other words, at a position that is not visible when the inside is viewed from the external communication hole. An internal communication hole is provided. With this configuration, an external magnetic field (hereinafter referred to as “external noise”) that is an external noise that has entered the first shield space through the external communication hole is confined in the third shield space, and the second shield in which the object is stored. It is possible to prevent external noise from entering the space.

  Application Example 2 In the application example described above, the partition member is a magnetic shield material.

  According to the application example described above, external noise that has entered the third shield space via the external communication hole enters the second shield space that houses the electronic device, electronic device, or the like that is the target object via the partition member. Can be prevented.

  Application Example 3 In the application example described above, the object and the device that evaluates the object are electrically connected by the internal wiring and the external wiring through the internal communication hole and the external communication hole. It is characterized by.

  To obtain result data such as measurement of an object in an environment free from external noise, and to collect, calculate, analyze, or drive the result by an external device, the object and the external device are electrically connected. Wiring is essential. Even if these wirings are connected via the external communication hole and the internal communication hole to connect the object stored in the second shield space to the external device, external noise that enters through the external communication hole passes through the internal communication hole. Therefore, it is possible to acquire or drive the measurement result of an object without external noise.

  Application Example 4 In the application example described above, the partition member is placed in the first shield space by a support member, and a part of the support member is disposed to face at least the external communication hole, and At least all projection ranges of the opening shape of the external communication hole projected in the communication direction of the external communication hole overlap.

  According to the above application example, the partition plate support member placed so as to face the external communication hole has a size exceeding the projection range of the opening shape of the external communication hole in the communication direction of the external communication hole, in other words. When the inside is viewed through the external communication hole, the support member is formed so that the support member appears to overlap all the external communication holes. Thereby, the external noise which invades from the external communication hole is shielded by the support member, and can be prevented from entering the central portion of the third shield space.

  Application Example 5 In the application example described above, at least the support member disposed to face the external communication hole is a magnetic shield material.

  According to the application example described above, since the support member is a magnetic shield material, not only shielding external noise but also passing magnetism inside the support member so as not to direct the magnetic force to the inside of the third shield space. A higher magnetic shielding effect can be obtained.

The top view of a 1st embodiment is shown. The A-A 'section sectional view of a 1st embodiment is shown. The B-B 'section sectional view of a 1st embodiment is shown. The conceptual diagram which shows the shield space in embodiment. The plane conceptual diagram which shows the example of arrangement | positioning of the supporting member in 1st Embodiment. (A) is a rectangular shape, (b) a combination of a plate shape and a column shape. Sectional drawing of 2nd Embodiment is shown.

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

(First embodiment)
FIG. 1 is a top view of a first embodiment of the present invention, and a part of the top surface is cut and displayed for convenience of explanation. 2 shows the AA ′ cross section of FIG. 1, and FIG. 3 shows the MM ′ cross section of FIG. FIG. 4 is a conceptual diagram showing the arrangement of the shield space. As shown in FIG. 2, the magnetic shield box 100 of the present embodiment places an object 30 by a base 10 formed of a magnetic shield material and a support member 20 placed and fixed on the base 10. Partition plate 40 to be provided. Furthermore, a shield cover 50 is provided that is formed by a magnetic shield material that covers the object 30 and is fixed to the base 10.

  As shown in FIG. 4, the magnetic shield box 100 configured as described above includes the first shield space 110 formed by the base 10 and the shield cover 50, and the first shield space 110 formed by the shield cover 50 and the partition plate 40. 2 shield space 120, base 10, shield cover 50, and third shield space 130 formed by partition plate 40.

  As shown in FIG. 2, the base 10 and the support member 20, and the base 10 and the shield cover 50 are fixed with screws 60. Similarly, the support member 20 and the partition plate 40 are also fixed with screws. The base 10 and the support member 20 and the support member 20 and the partition plate 40 can be joined by welding or the like, but when using a high magnetic permeability material described later, by applying thermal stress such as welding. In order to cause a decrease in magnetic permeability, heat treatment such as annealing must be performed. Therefore, fixing with screws as shown in this embodiment is preferable.

  Further, on the side surface of the shield cover 50, a shield cover communication hole 51 (corresponding to the external communication hole in the claims) is formed in the shield cover 50 at a position corresponding to a portion where the third shield space 130 shown in FIG. 4 is formed. ) Is formed. The shield cover communication hole 51 is fitted with a connector 81 that can be connected to the connector 71 of the external wiring 70 that is electrically connected to a device (not shown). An internal wiring 80 wired inside the magnetic shield box 100 is connected to the connector 81.

  The support member 20 includes at least a support member 20a disposed at a position facing the shield cover communication hole 51, and a support member 20b disposed at a support point that supports the partition plate 40 together with the support member 20a. The internal wiring 80 is routed through a wiring space 130 a formed by the support member 20 a facing the shield cover communication hole 51, the shield cover 50, and the partition plate 40.

  As described above, the magnetic shield box 100 has to connect the external wiring 70 connected to the external device and the internal wiring 80. In order to arrange the connector 81 for connection, the shield cover communication hole 51 is used. Is necessarily provided on the shield cover 50. Even if the shield cover communication hole 51 is provided with the connector 81, it cannot shield the magnetic field lines from the outside, and even if it is weak through the shield cover communication hole 51, the magnetic field lines penetrate into the magnetic shield box 100. Come.

  By providing the support member 20a so as to oppose the shield cover communication hole 51 against the magnetic force lines entering from the shield cover communication hole 51, the magnetic force lines entering from the shield cover communication hole 51 can be shielded by the support member 20a. it can. Furthermore, by forming the support member 20a from the same magnetic shield material as the base 10 and the shield cover 50, it is possible to reliably shield the magnetic lines of force that enter from the shield cover communication hole 51.

  Further, by drawing the internal wiring 80 into the wiring space 130 a of the third shield space 130, the magnetic lines of force that can also be generated from the internal wiring 80 enter the second shield space 120 in which the object 30 is stored by the partition plate 40. Can also be shielded. Furthermore, by forming the partition plate 40 with a magnetic shield material, the wiring space 130a becomes a space surrounded by the magnetic shield material, and the shielding of the lines of magnetic force can be made more reliable.

  As a magnetic shield material used for the base 10, the shield cover 50, the support member 20, and the partition plate 40, it is desirable to use a material having high magnetic permeability. Although it is common to use an iron-based metal for the magnetic shield, it is more preferable to use a material having high magnetic permeability.

  For example, permalloy, which is an alloy of iron and nickel, or pure iron is known as a material having high magnetic permeability, but permalloy can be preferably used. Permalloy has a magnetic permeability of about 60,000 to 200,000, which is extremely high when applied to the magnetic shield box 100 of the present invention against an external magnetic field, while the magnetic permeability of a general steel sheet is about 2100. Magnetic shielding can be realized. Therefore, as a material applied to the magnetic shield box of the present invention, a material having a permeability equivalent to permalloy is preferably used.

  As shown in FIG. 1, the partition plate 40 is formed with a partition plate communication hole 41 that communicates the third shield space and the second shield space 120. As shown in FIG. 3, the partition plate communication hole 41 connects the internal wiring 80 to the object 30 and the internal wiring 80 accommodated in the second shield space 120 via the connector 82 and the connector 31. 2 It is provided for drawing into the shield space 120. Therefore, the partition plate communication hole 41 is not limited to the circular through-hole shown in FIG. 1, and may be a polygonal shape or a notch shape.

  The position where the partition plate communication hole 41 is provided is set to a large distance H from the plane distance L shown in FIG. 1 or the virtual space Q shown in FIGS. 1 and 3 in which the opening shape of the shield cover communication hole 51 is extended in the communication direction. It is preferable to do. In particular, it is preferable that the virtual space Q and the partition plate communication hole 41 do not overlap. By arranging the partition plate communication hole 41 in this way, the external noise that has entered from the shield cover communication hole 51 is shielded by the support member 20a disposed opposite to the shield cover communication hole 51. Even if it occurs, it is possible to prevent external noise from passing through the partition plate communication hole 41 and to exhibit high shielding properties against external noise.

  Further, the internal wiring 80 is routed through the third shield space 130 so as to be introduced into the partition plate communication hole 41. Therefore, the magnetic lines of force that may be generated from the internal wiring 80 are also shielded from entering the second shield space 120 by the partition plate 40, and the influence of magnetism on the object can be prevented.

  FIG. 5 is a plan view schematically showing the arrangement of the support member 20 as another embodiment of the support member 20. FIG. 5A is a plan view when arranged in a rectangular shape, and FIG. 5B is a plan view when the support member 20b is arranged in a columnar shape. As shown in FIG. 5A, when the support member 20 is arranged in a rectangular shape and the support member 20 is formed of a magnetic shield material, the magnetic lines of force from the internal wiring 80 can be reliably shielded. That is, by making the wiring space 130a in FIG. 4 an independent shield space, a double shield effect can be obtained.

  Further, as shown in FIG. 5B, the support member 20a facing the shield cover communication hole 51 can be formed in a plate shape, and the opposite support member 20b can be formed in a column shape, for example. That is, as described above, since the external noise entering from the shield cover communication hole 51 can be shielded by the support member 20a, the support member 20b which is not on the shield cover communication hole 51 side can be used in a simple form. The effect can be. Further, in the case of a simple shape such as a columnar shape, the support member 20b need not be formed of a magnetic shield material. For example, you may form with aluminum and resin.

In the case of the form of the support member 20 shown in FIG. 5B, the set value W of the width of the support member 20a facing the shield cover communication hole 51 is set to be wider than at least w determined by the following calculation formula: External noise entering from the shield cover communication hole 51 can be reliably shielded. That is, the set value W is determined so that an intrusion of external noise intersects the support member 20a with a virtual line L that connects the outer end p of the shield cover communication hole 51 and the inner end q opposite to the outer end p. By doing so, the magnetic field lines of external noise can be blocked.
w = E × (D / t)
E: Shield cover communication hole opening diameter D: Distance between shield cover and support member t: Shield cover plate thickness

(Second Embodiment)
In the first embodiment described above, the shield cover 50 is provided with a communication hole for connecting to the external wiring 70, but an embodiment in which the external communication hole is provided in the base will be described as a second embodiment. Since the second embodiment differs from the first embodiment only in the arrangement of the external communication holes, the description of the parts common to the first embodiment is omitted, and the same reference numerals are given to the common components. A description will be given.

  FIG. 6 is a cross-sectional view of a magnetic shield box 200 according to the second embodiment. The magnetic shield box 200 includes support legs 90 on the side opposite to the fixed side of the shield cover 50 of the base 10. The base 10 is provided with a base communication hole 11 for disposing a connector 81 of an internal wiring 80 for connection with a connector 71 of an external wiring 70 connected to an external device. The base communication hole 11 communicates with the third shield space 130 and the outside, but is preferably provided at a position where the wiring space 130a formed by the base 10, the shield cover 50, and the support member 20a communicates with the outside. . Further, the partition plate communication hole 41 is provided in a range of a virtual space Q ′ obtained by extending the opening shape of the base communication hole 11 in the communication direction so that the partition plate communication hole 41 (not shown) does not overlap.

  In the second embodiment configured as described above, the object 30 has a double shielding structure by the base 10 formed by the magnetic shield material and the partition plate 40 with respect to the magnetic lines of force from the lower side of the base 10 in the drawing, A reliable magnetic shielding effect can be exhibited even against extremely strong lines of magnetic force. Furthermore, even if the magnetic force lines enter through the base communication hole 11, the partition plate communication hole 41 is not disposed on the opening extension of the base communication hole 11, thereby allowing the partition plate 40 to enter the second shield space 120. The shielding effect to prevent can be acquired. In addition, by routing the internal wiring 80 in the wiring space 130a, the magnetic flux generated from the internal wiring 80 is also shielded from entering the second shield space 120 by the partition plate 40, and the magnetic effect on the object 30 is prevented. Can be suppressed.

(Application examples)
As described above, the magnetic shield box 100 is formed by forming the base 10, the support member 20, the partition plate 40, and the shield cover 50 with a magnetic shield material, so that an external magnetic field, that is, an external magnetic field line is transferred to the inside of the magnetic shield box 100. However, by applying this configuration, an electromagnetic shield box that shields electromagnetic waves (electromagnetic rays) can also be formed. That is, it can be realized by using the electromagnetic shield material instead of the magnetic shield material for the base 10, the support member 20, the partition plate 40 and the shield cover 50.

  As the electromagnetic shielding material, for example, aluminum, copper or the like is a material suitable for electromagnetic shielding. By using the same configuration as that of the magnetic shield box of the first embodiment or the second embodiment with these materials, an electromagnetic shield box having high electromagnetic shielding properties can be realized.

  Furthermore, at least the base 10 and the shield cover 50 of the first embodiment and the second embodiment are made of a multilayer material in which an electromagnetic wave shielding material is attached to a magnetic shielding material, thereby shielding both magnetic lines and electromagnetic rays. A shield box can be obtained.

  DESCRIPTION OF SYMBOLS 10 ... Base, 20 ... Support member, 30 ... Object, 40 ... Partition plate, 50 ... Shield cover, 51 ... Shield cover communication hole, 60 ... Screw, 70 ... External wiring, 71 ... Connector, 80 ... Internal wiring, 81: Connector.

Claims (5)

A magnetic shield box that prevents external magnetism or electromagnetic waves from entering inside,
A first shield space surrounded by a magnetic shield material;
A second shield space for storing an object divided by a partition member placed in the first shield space, and a third shield space for introducing an internal wiring;
Comprising at least one external communication hole communicating the outside of the magnetic shield box and the third shield space;
The partition member includes at least one internal communication hole that communicates the second shield space and the third shield space;
The internal communication hole does not overlap with an extension obtained by linearly extending the opening shape of the external communication hole along the communication direction of the external communication hole;
Magnetic shield box characterized by that. The partition member is a magnetic shield material;
The magnetic shield box according to claim 1. The object and the device for evaluating the object are electrically connected by the internal wiring and the external wiring through the internal communication hole and the external communication hole,
The magnetic shield box according to claim 1, wherein the magnetic shield box is a magnetic shield box. The partition member is placed in the first shield space by a support member,
A part of the support member is arranged to face at least the external communication hole,
And at least all of the projection range of the opening shape of the external communication hole projected in the communication direction of the external communication hole overlaps,
The magnetic shield box according to claim 1, wherein the magnetic shield box is a magnetic shield box. At least the support member disposed to face the external communication hole is a magnetic shield material;
The magnetic shield box according to claim 1, wherein the magnetic shield box is a magnetic shield box.

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