Electronic device

Abstract

To obtain a sufficient magnetic shielding effect against magnetic field coupling while suppressing an increase in weight.SOLUTION: An electronic device includes a first magnetic field generating unit having an electric path through which current flows when energized, which is formed in a loop shape that generates a magnetic field, a second magnetic field generating unit spaced apart in a first direction from the first magnetic field generating unit, having an electric path through which current flows when energized, which is formed in a loop shape that generates a magnetic field, and a first magnetic shielding member arranged within a predetermined proximity dimension range from the first magnetic field generating unit, and the first magnetic shielding member is formed from a conductive material and includes a first conductive portion with an opening in the center when viewed from the first direction, and the first conductive portion is formed such that at least a portion of it overlaps with the first magnetic field generating unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an electronic device.

Background Art

[0002] It is desired to suppress the influence of electromagnetic noise radiated from various electrical devices. In contrast, for example, Patent Document 1 discloses a configuration in which a conductive plate is stretched as a magnetic shield member at a position away from an electrical device at an opening of a shield case that houses an electrical device including a circuit that radiates electromagnetic noise. Further, Patent Document 2 discloses a configuration in which a partition having a magnetic shielding effect is provided as a magnetic shield member in a housing in order to suppress the leakage magnetic flux from a reactor or a bus bar housed in the housing from affecting other electronic components (current sensors).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, due to the layout on the substrate of a plurality of elements provided on the circuit board and the circuit pattern connecting these plurality of elements, the path (circuit) of the current flowing during driving may unintentionally be configured in a loop shape. A loop-shaped current path also generates a magnetic field. When there are a plurality of such loop-shaped current paths within the range of the generated magnetic field, magnetic field coupling may occur between the magnetic field generated by one loop-shaped current path and the magnetic field generated by another loop-shaped current path. In order to suppress such magnetic field coupling, it is conceivable to provide a magnetic shield member as disclosed in Patent Documents 1 and 2.

[0005] However, the magnetic shield members disclosed in Patent Documents 1 and 2 are formed of a metal material such as iron. Moreover, in order to obtain a sufficient magnetic shielding effect, the magnetic shield member often has a certain thickness, which leads to an increase in the weight of the magnetic shield member and the electronic device provided with the magnetic shield member.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to provide an electronic device that can obtain a sufficient magnetic shielding effect against magnetic field coupling while suppressing an increase in weight.

Means for Solving the Problems

[0007] In order to solve the above problems, the electronic device according to the present disclosure includes a first magnetic field generating portion in which a circuit through which current flows when energized is formed in a loop shape that generates a magnetic field, and a second magnetic field generating portion that is provided at a distance from the first magnetic field generating portion in a first direction and in which a circuit through which current flows when energized is formed in a loop shape that generates a magnetic field, and a first magnetic shield member disposed within a range of a preset proximity dimension with respect to the first magnetic field generating portion. The first magnetic shield member is formed of a conductive material and has a first conductive portion having an opening at the center when viewed from the first direction. At least a part of the first conductive portion is formed so as to overlap the first magnetic field generating portion.

Effects of the Invention

[0008] According to the electronic device of the present disclosure, it is possible to obtain a sufficient magnetic shielding effect against magnetic field coupling while suppressing an increase in weight.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments for implementing an electronic device according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited only to these embodiments. (Configuration of the electronic device) FIG. 1 is a schematic diagram showing a schematic configuration of an electronic device according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view of the electronic device. Examples of the electronic device according to the embodiment of the present disclosure include, for example, an EMC (Electro Magnetic Compatibility) filter provided in a power converter that converts current between alternating current and direct current, a motor (electric motor), and the like. This EMC filter may be for direct current or for three-phase alternating current. The electronic device according to the embodiment of the present disclosure is not limited to an EMC filter, and may be an electronic device for other uses and other structures.

[0011] As shown in FIGS. 1 and 2, the electronic device 1A includes a housing 2, a first magnetic field generating unit 3, a second magnetic field generating unit 4, and a first shielding member 5.

[0012] The housing 2 is formed of a conductive metal material or the like. The housing 2 houses a device main body (not shown) constituting the electronic device 1A. The device main body includes, for example, various electronic components such as resistors, capacitors, coils, bus bars, a circuit board on which these various electronic components are mounted, wiring, and the like. Here, the specific configuration of the device main body is not limited at all and may be any configuration. DC or AC power is supplied to the device main body from a power source (not shown) provided outside the housing 2. The device main body exhibits required functions by the power supplied from the outside.

[0013] Each of the first magnetic field generating unit 3 and the second magnetic field generating unit 4 is generated by energizing the above-described electronic components, circuit board, wiring, etc. with the power supplied from the outside with respect to the device main body as described above. Specifically, for example, when one electronic component (for example, a bus bar) among the electronic components constituting the device main body is formed in a loop shape, a current path through which current flows during energization is formed in a loop shape. Also, for example, in an electric circuit constituted by a plurality of electronic components such as electronic components, a circuit board, and wiring constituting the device main body, a current path through which current flows during energization may be formed in a loop shape as a whole. More specifically, for example, as a result of current flowing through a wiring pattern formed on a circuit board on which a plurality of electronic components are mounted, when viewed from a direction orthogonal to the surface of the circuit board, the current path (current path) flowing along the wiring pattern may be in a loop shape.

[0014] Each of the first magnetic field generating unit 3 and the second magnetic field generating unit 4 refers to a portion that generates a magnetic field by magnetic flux extending in a direction intersecting the plane in which the loop-shaped current path is located as a result of the loop-shaped current path being formed when energized as described above.

[0015] Here, the loop shape refers to a shape such as a circular shape or a C-shaped shape in which the circuit extends in the circumferential direction. In an electric circuit, the wiring pattern through which current flows extends so as to connect the input-side terminal and the output-side terminal. Therefore, the circuit formed in a loop shape is not continuous over the entire circumference, but extends as a whole in a circular shape, C-shaped shape, etc. from the input side to the output side. Furthermore, as long as the circuit formed in a loop shape is formed in a loop shape as a whole, it is not limited to an arc shape, but may be a rectangular shape, a polygonal shape, etc., or may extend in a zigzag shape or the like along the shape of the wiring pattern on the circuit board.

[0016] Also, each of the first magnetic field generating unit 3 and the second magnetic field generating unit 4 is not necessarily formed on a single circuit board. In the device body, as a result of current flowing across a plurality of circuit boards that are connected to each other and arranged three-dimensionally, even a circuit formed in a loop shape generates the first magnetic field generating unit 3 and the second magnetic field generating unit 4 that generate a magnetic field. Also, the first magnetic field generating unit 3 and the second magnetic field generating unit 4 are not necessarily always formed when energized, and may be temporarily generated depending on the state of the circuit energized by switching or the like.

[0017] In FIG. 1, the first magnetic field generating unit 3 and the second magnetic field generating unit 4 are schematically shown as a rectangular frame shape, for example. As described above, the specific shapes of the first magnetic field generating unit 3 and the second magnetic field generating unit 4 vary depending on the component layout of the actual device body. The first magnetic field generating unit 3 and the second magnetic field generating unit 4 are housed in the housing 2.

[0018] The first magnetic field generating unit 3 and the second magnetic field generating unit 4 are formed spaced apart in the first direction X within the housing 2. The second magnetic field generating unit 4 is formed spaced apart from the first magnetic field generating unit 3 in the first direction X. The first magnetic field generating unit 3 and the second magnetic field generating unit 4 are provided within the range where the magnetic field generated by the first magnetic field generating unit 3 and the magnetic field generated by the second magnetic field generating unit 4 are magnetically coupled when the first shielding member 5 described later does not exist.

[0019] In an embodiment of the present disclosure, each of the first magnetic field generating unit 3 and the second magnetic field generating unit 4 is schematically formed along a plane intersecting the first direction X. The plane intersecting the first direction X is, in the embodiment of the present disclosure, the Y-Z plane including both the second direction Y orthogonal to the first direction X and the third direction Z orthogonal to the first direction X and the second direction Y.

[0020] The first shielding member 5 is disposed between the first magnetic field generating unit 3 and the second magnetic field generating unit 4 in the first direction X. The first shielding member 5 is disposed close to the first magnetic field generating unit 3 in the first direction X. That is, the first shielding member 5 is separated from the first magnetic field generating unit 3 in the first direction X and is disposed within a preset proximity dimension D with respect to the first magnetic field generating unit 3.

[0021] Here, the proximity dimension D is preferably set such that, for example, 0.5 mm ≤ D ≤ 5 mm. By disposing the first shielding member 5 close to the first magnetic field generating unit 3 within the range of such a proximity dimension D, it is possible to suppress the magnetic field generated by the first magnetic field generating unit 3 from reaching the second magnetic field generating unit 4 side and the magnetic field generated by the second magnetic field generating unit 4 from reaching the first magnetic field generating unit 3 side. If the proximity dimension D is larger than the above range, the shielding performance by the first shielding member 5 rapidly deteriorates. Further, if the proximity dimension D is smaller than the above range, the first shielding member 5 and the first magnetic field generating unit 3 are likely to come into contact during assembly or the like, resulting in a decrease in assemblability.

[0022] The first shielding member 5 is formed of a conductive material such as a metal having conductivity. The first shielding member 5 is formed in a plate shape extending along a plane intersecting the first direction X. The first shielding member 5 has a first conductive portion 51 having an opening 52 at the central portion when viewed from the first direction X. When viewed from the first direction X, at least a part of the first conductive portion 51 is formed so as to overlap with the first magnetic field generating portion 3. In the embodiment of the present disclosure, when viewed from the first direction X, the entire first conductive portion 51 is formed so as to overlap with the first magnetic field generating portion 3. For this, it is preferable that the opening 52 has the same shape and the same size as the inner peripheral edge 3s of the first magnetic field generating portion 3 extending in a loop shape when viewed from the first direction X. Also, it is preferable that the outer peripheral edge 5t of the first shield member 5 is positioned outside the outer peripheral edge 3t of the first magnetic field generating portion 3 when viewed from the first direction X.

[0023] Note that the entire first conductive portion 51 does not necessarily have to overlap with the first magnetic field generating portion 3 when viewed from the first direction X. The first conductive portion 51 may be formed such that only a part thereof overlaps with the first magnetic field generating portion 3 when viewed from the first direction X. For example, the opening 52 may be formed so as to be positioned inside or outside in a direction intersecting the first direction X with respect to the inner peripheral edge 3s of the first magnetic field generating portion 3. For example, the outer peripheral edge 5t of the first conductive portion 51 may be formed so as to be positioned inside in a direction intersecting the first direction X with respect to the outer peripheral edge 3t of the first magnetic field generating portion 3. Also, in the first conductive portion 51, it is preferable that each of the first extension portion 51a extending in the second direction Y and the second extension portion 51b extending in the third direction Z has a width intersecting the extension direction of 1 mm or more. Also, the thickness of the first conductive portion 51 in the first direction X is preferably 0.1 mm or more. In this way, heat generation when current flows through the first conductive portion 51 due to a magnetic field is suppressed.

[0024] (Function and effect) In the electronic device 1A having the above configuration, a first shielding member 5 is provided between the first magnetic field generating portion 3 and the second magnetic field generating portion 4. Since the first conductive portion 51 of the first shielding member 5 has the opening 52, an increase in weight is suppressed. Since at least a part of the first conductive portion 51 overlaps with the first magnetic field generating portion 3 when viewed from the first direction X and is provided within the range of the proximity dimension D with respect to the first magnetic field generating portion 3, an effective shielding effect can be obtained for the magnetic field coupling between the first magnetic field generating portion 3 and the second magnetic field generating portion 4. As a result, it is possible to obtain a sufficient shielding effect against magnetic field coupling while suppressing an increase in weight.

[0025] Also, in the above embodiment, when viewed from the first direction X, the entire first conductive portion 51 overlaps with the first magnetic field generating portion 3. Thereby, the shielding effect by the first shielding member 5 can be further enhanced.

[0026] Also, in the above embodiment, the first magnetic field generating portion 3 and the second magnetic field generating portion 4 are formed along a plane intersecting the first direction X. Thereby, the first magnetic field generating portion 3, the second magnetic field generating portion 4, and the first shielding member 5 disposed between the first magnetic field generating portion 3 and the second magnetic field generating portion 4 are arranged in parallel. Thereby, the first shielding member 5 can be disposed to face in a state of being close to the entire circumference of the loop-shaped first magnetic field generating portion 3. Therefore, the shielding effect by the first shielding member 5 can be efficiently exhibited.

[0027] (Second Embodiment) Next, a second embodiment of the electronic device according to the present disclosure will be described. In the second embodiment described below, the same reference numerals are given to the configurations common to the first embodiment, and the description thereof is omitted. The second embodiment is different from the first embodiment in that it has a second shielding member.

[0028] FIG. 3 is a schematic configuration diagram showing a schematic configuration of an electronic device according to the second embodiment of the present disclosure. As shown in FIG. 3, the electronic device 1B includes a housing 2, a first magnetic field generation unit 3, a first magnetic field generation unit 3, a second shield member 6, and a second shield member 6.

[0029] The electronic device 1B according to the embodiment of the present disclosure includes a second shield member 6 in addition to the configuration of the electronic device 1A shown in the first embodiment. The second shield member 6 is disposed between the first magnetic field generation units 3 in the first direction X. The second shield member 6 is disposed close to the second magnetic field generation unit 4 in the first direction X. That is, the second shield member 6 is separated from the second magnetic field generation unit 4 in the first direction X and is disposed within a preset proximity dimension D with respect to the second magnetic field generation unit 4.

[0030] By disposing the second shield member 6 close to the second magnetic field generation unit 4 within the range of the proximity dimension D, it is possible to suppress the magnetic field generated by the second magnetic field generation unit 4 from reaching the first magnetic field generation unit 3 side and the magnetic field generated by the first magnetic field generation unit 3 from reaching the second magnetic field generation unit 4 side.

[0031] The second shield member 6 is formed of a conductive material such as a metal having conductivity. The second shield member 6 is formed in a plate shape extending along a plane intersecting the first direction X. The second shield member 6 has a second conductive portion 61 having an opening 62 at the center when viewed from the first direction X. The second conductive portion 61 is formed such that at least a part of it overlaps the second magnetic field generation unit 4 when viewed from the first direction X. In the embodiment of the present disclosure, the second conductive portion 61 is formed such that its entirety overlaps the second magnetic field generation unit 4 when viewed from the first direction X.

[0032] (Function and effect) In the electronic device 1B having the above configuration, similar to the first embodiment, a first shield member 5 is provided between the first magnetic field generation unit 3 and the second magnetic field generation unit 4. Thereby, it is possible to obtain a sufficient shielding effect against magnetic field coupling while suppressing an increase in weight. Furthermore, the electronic device 1B of the present embodiment includes a second shielding member 6. Since the second conductive portion 61 of the second shielding member 6 has an opening 62, an increase in weight is suppressed. At least a part of the second conductive portion 61 overlaps with the second magnetic field generating portion 4 when viewed from the first direction X and is provided within a range of a proximity dimension with respect to the second magnetic field generating portion 4, so that while suppressing an increase in weight, a sufficient shielding effect against magnetic coupling can be obtained.

[0033] (Other Embodiments) As described above, the embodiments of the present disclosure have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within a range not departing from the gist of the present disclosure are also included. In the above embodiment, the first magnetic field generating portion 3 and the second magnetic field generating portion 4 have been mentioned. However, since the configuration is merely schematically shown as described above, the specific configuration can be appropriately changed according to the actual configuration of the device body.

[0034] (Consideration Example) Regarding the configuration shown in the second embodiment above, a study by simulation was conducted, and the results are shown below. The model as an example was as shown in FIG. 3. For comparison, as shown in FIG. 4, a model M1 without the first shielding member 5 and the second shielding member 6 was prepared between the first magnetic field generating portion 3 and the second magnetic field generating portion 4 (Comparative Example 1). Also, for comparison, as shown in FIG. 5, a model M2 including a shielding member 9 made of a conductive material that partitions the inside of the housing 2 into one side and the other side in the first direction X was prepared at an intermediate position between the first magnetic field generating portion 3 and the second magnetic field generating portion 4 (Comparative Example 2).

[0035] For each of the models of the example, Comparative Example 1, and Comparative Example 2, a direct current with the same current value was supplied by simulation, and the magnetic coupling strength between the first magnetic field generating portion 3 and the second magnetic field generating portion 4 generated at that time was calculated. As a result, in Comparative Example 1 without the first shielding member 5 and the second shielding member 6, the magnetic coupling strength was 0.178 (nH), whereas in Comparative Example 2 with the shielding member 9, the magnetic coupling strength was 0.072 (nH). Thus, it was confirmed that a shielding effect on magnetic coupling by the shielding member 9 can be obtained. On the other hand, in the embodiment including the first shielding member 5 and the second shielding member 6, the magnetic coupling strength was 0.073 (nH). Thus, it was confirmed that even in the first shielding member 5 and the second shielding member 6, which are lightened by providing the openings 52 and 62, a shielding effect on magnetic coupling equivalent to that of the shielding member 9 can be obtained.

[0036] <Appendix> The electronic devices 1A and 1B described in each embodiment are understood as follows, for example.

[0037] (1) The electronic devices 1A and 1B according to the first aspect include a first magnetic field generating portion 3 in which a circuit through which current flows when energized is formed in a loop shape that generates a magnetic field, and a second magnetic field generating portion 4 that is provided at a distance in the first direction X from the first magnetic field generating portion 3 and in which a circuit through which current flows when energized is formed in a loop shape that generates a magnetic field. The electronic devices 1A and 1B also include a first shielding member 5 disposed within a range of a preset proximity dimension D with respect to the first magnetic field generating portion 3. The first shielding member 5 is formed of a conductive material and has a first conductive portion 51 having an opening 52 at the center when viewed from the first direction X. At least a part of the first conductive portion 51 is formed so as to overlap the first magnetic field generating portion 3 when viewed from the first direction X.

[0038] In these electronic devices 1A and 1B, a first shielding member 5 is provided between a first magnetic field generating portion 3 and a second magnetic field generating portion 4. Since the first conductive portion 51 of the first shielding member 5 has an opening 52, an increase in weight is suppressed. At least a part of the first conductive portion 51 overlaps with the first magnetic field generating portion 3 when viewed from the first direction X, and is provided within a range of a proximity dimension with respect to the first magnetic field generating portion 3, so that a sufficient shielding effect against magnetic field coupling can be exerted. As a result, it is possible to obtain a sufficient shielding effect against magnetic field coupling while suppressing an increase in weight.

[0039] (2) The electronic devices 1A and 1B according to the second aspect are the electronic devices 1A and 1B of (1), wherein the first conductive portion 51 is formed so as to entirely overlap with the first magnetic field generating portion 3 when viewed from the first direction X.

[0040] Thereby, when the first conductive portion 51 entirely overlaps with the first magnetic field generating portion 3 when viewed from the first direction X, the shielding effect by the first shielding member 5 can be further enhanced.

[0041] (3) The electronic devices 1A and 1B according to the third aspect are the electronic devices 1A and 1B of (1) or (2), wherein the first magnetic field generating portion 3 and the second magnetic field generating portion 4 are formed along a plane intersecting the first direction X.

[0042] Thereby, the first magnetic field generating portion 3, the second magnetic field generating portion 4, and the first shielding member 5 disposed between the first magnetic field generating portion 3 and the second magnetic field generating portion 4 are arranged in parallel. Thereby, the first shielding member 5 can be disposed opposite in a state of being close to the entire circumference of the loop-shaped first magnetic field generating portion 3. The shielding effect by the first shielding member 5 can be efficiently exerted.

[0043] (4) The electronic device 1B according to the fourth aspect is any one of the electronic devices 1B of (1) to (3), and includes a second shield member 6 disposed within a range of a preset proximity dimension D with respect to the second magnetic field generating unit 4. The second shield member 6 is formed of a conductive material and has a second conductive portion 61 having an opening 62 at the center when viewed from the first direction X. At least a part of the second conductive portion 61 is formed so as to overlap the second magnetic field generating unit 4.

[0044] As a result, in addition to the first shield member 5, a second shield member 6 is provided between the first magnetic field generating unit 3 and the second magnetic field generating unit 4. Since the second conductive portion 61 of the second shield member 6 has the opening 62, an increase in weight is suppressed. At least a part of the second conductive portion 61 overlaps the second magnetic field generating unit 4 when viewed from the first direction X and is provided within the range of the proximity dimension D with respect to the second magnetic field generating unit 4, thereby enhancing the shielding effect against magnetic field coupling. As a result, it is possible to obtain a sufficient shielding effect against magnetic field coupling while suppressing an increase in weight.

Explanation of Reference Numerals

[0045] 1A, 1B... Electronic devices 2... Housing 3... First magnetic field generating unit 3s... Inner peripheral edge 3t... Outer peripheral edge 4... Second magnetic field generating unit 5... First shield member 5t... Outer peripheral edge 6... Second shield member 9... Shield member 51... First conductive portion 51a... First extension 51b... Second extension 52... Opening 61... Second conductive portion 62... Opening D... Proximity dimension

Claims

1. A first magnetic field generating portion in which a circuit through which current flows when energized is formed in a loop shape that generates a magnetic field, a second magnetic field generating portion that is provided at a distance from the first magnetic field generating portion in a first direction and in which a circuit through which current flows when energized is formed in a loop shape that generates a magnetic field, and a first magnetic shielding member disposed within a range of a preset proximity dimension with respect to the first magnetic field generating portion. The first magnetic shielding member is formed of a conductive material and has a first conductive portion having an opening at a central portion when viewed from the first direction. The first conductive portion is formed such that at least a part thereof overlaps the first magnetic field generating portion when viewed from the first direction. An electronic device.

2. The first conductive portion is formed such that its entirety overlaps the first magnetic field generating portion when viewed from the first direction. The electronic device according to Claim 1.

3. The first magnetic field generating portion and the second magnetic field generating portion are formed along a plane intersecting the first direction. The electronic device according to Claim 1 or 2.

4. and a second magnetic shielding member disposed within a range of a preset proximity dimension with respect to the second magnetic field generating portion. The second magnetic shielding member is formed of a conductive material and has a second conductive portion having an opening at a central portion when viewed from the first direction. The second conductive portion is formed such that at least a part thereof overlaps the second magnetic field generating portion. The electronic device according to Claim 1 or 2.

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