Electronic device

Abstract

The present invention is provided with: a first magnetic field generation part in which an electric path, through which a current flows during energization, is formed in a loop shape that generates a magnetic field; a second magnetic field generation part which is provided spaced apart in a first direction from the first magnetic field generation part and in which an electric path, through which a current flows during energization, is formed in a loop shape that generates a magnetic field; and a first magnetic shield member which is disposed within a range of a preset proximity dimension with respect to the first magnetic field generation part. The first magnetic shield member is formed of a conductive material, and has a first conductive part having an opening at a central part when viewed from the first direction. The first conductive part is formed such that at least a part thereof overlaps with the first magnetic field generation part.

Description

Electronic Devices

[0001] This application claims priority to Japanese Patent Application No. 2023-202756, filed on November 30, 2023, the contents of which are incorporated herein by reference.

[0002] It is desirable to suppress the effects of electromagnetic noise emitted from various electrical devices. In response to this, for example, Patent Document 1 discloses a configuration in which a conductive plate is stretched across an opening of a shielding case that houses an electrical device including a circuit that emits electromagnetic noise, as a magnetic shielding member, at a position away from the electrical device. Furthermore, Patent Document 2 discloses a configuration in which a partition having a magnetic shielding effect is provided within the case as a magnetic shielding member to suppress leakage magnetic flux from a reactor or bus bar housed within the case from affecting other electronic components (current sensors).

[0003] JP 2007-88332 A JP 2021-145486 A

[0004] However, due to the layout of multiple elements provided on a circuit board and the circuit patterns connecting these multiple elements on the board, the path (electrical circuit) of current flowing during operation may unintentionally be configured as a loop. A looped current path also generates a magnetic field. When multiple such looped current paths exist within the range of the generated magnetic field, magnetic field coupling may occur between the magnetic field generated by one looped current path and the magnetic field generated by another looped current path. To suppress such magnetic field coupling, it is possible to provide a magnetic shielding member, as disclosed in Patent Documents 1 and 2.

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

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

[0007] In order to solve the above problem, the electronic device of the present disclosure comprises: a first magnetic field generating unit, in which an electric path through which current flows when energized is formed in a loop shape that generates a magnetic field; a second magnetic field generating unit, which is spaced apart from the first magnetic field generating unit in a first direction and in which an electric path through which current flows when energized is formed in a loop shape that generates a magnetic field; and a first magnetic shielding member, which is arranged within a predetermined proximity dimension range of the first magnetic field generating unit, wherein the first magnetic shielding member is formed from a conductive material and has a first conductive portion with an opening in the center when viewed from the first direction, and the first conductive portion is formed so that at least a portion of it overlaps with the first magnetic field generating unit.

[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.

[0009] Fig. 1 is a schematic diagram showing a schematic configuration of an electronic device according to a first embodiment of the present disclosure; Fig. 2 is a cross-sectional view of the electronic device; Fig. 3 is a schematic diagram showing a schematic configuration of an electronic device according to a second embodiment of the present disclosure; Fig. 4 is a schematic diagram showing a schematic configuration of an electronic device as a comparative example used in a study by simulation; Fig. 5 is a schematic diagram showing a schematic configuration of an electronic device as another comparative example used in a study by simulation.

[0010] Hereinafter, embodiments of an electronic device according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to these embodiments. (Configuration of Electronic Device) FIG. 1 is a schematic diagram showing a general 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 electronic devices according to embodiments of the present disclosure include a power converter that converts current between AC and DC, an EMC (Electro Magnetic Compatibility) filter provided in a motor (electric motor), etc. This EMC filter may be for DC current or for three-phase AC current. The electronic device according to embodiments of the present disclosure is not limited to an EMC filter, and may also be an electronic device for other applications or with 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 shield member 5.

[0012] The housing 2 is made of a conductive metal material or the like. The housing 2 houses a device main body (not shown) that constitutes the electronic device 1A. The device main body is configured to include, for example, various electronic components such as resistors, capacitors, coils, and bus bars, a circuit board on which these various electronic components are mounted, wiring, etc. Here, the specific configuration of the device main body is not limited in any way and may have any configuration. The device main body is supplied with DC or AC power from a power source (not shown) provided outside the housing 2. The device main body performs its required functions using 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 electronic components, circuit board, wiring, etc. described above with power supplied from an external source to the device main body. Specifically, for example, if one of the electronic components constituting the device main body (e.g., a bus bar) is formed in a loop shape, the electrical path through which current flows when energized is formed in a loop shape. Also, for example, in an electrical circuit formed by multiple electronic components constituting the device main body, such as electronic components, circuit boards, and wiring, the electrical path through which current flows when energized may be formed in a loop shape as a whole. More specifically, for example, when current flows through a wiring pattern formed on a circuit board on which multiple electronic components are mounted, the flow path (electrical path) of the current flowing along the wiring pattern may be looped when viewed from a direction perpendicular to the surface of the circuit board.

[0014] As described above, each of the first magnetic field generating unit 3 and the second magnetic field generating unit 4 refers to a part that generates a magnetic field by magnetic flux extending in a direction intersecting the plane on which the loop-shaped electric path is located, as a result of the formation of an electric path through which current flows in a loop when current is applied.

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

[0016] Furthermore, the first magnetic field generating unit 3 and the second magnetic field generating unit 4 are not necessarily formed on a single circuit board. In the device body, even if a loop-shaped electric path is formed as a result of current flowing across multiple circuit boards that are connected to each other and arranged three-dimensionally, the first magnetic field generating unit 3 and the second magnetic field generating unit 4 that generate magnetic fields are generated. Furthermore, the first magnetic field generating unit 3 and the second magnetic field generating unit 4 are not necessarily always formed when current is applied, but may be temporarily generated depending on the state of the electric path when current is applied by switching or the like.

[0017] 1, the first magnetic field generator 3 and the second magnetic field generator 4 are shown, for example, in a schematic rectangular frame shape. As described above, the specific shapes of the first magnetic field generator 3 and the second magnetic field generator 4 vary depending on the component layout of the actual device body. The first magnetic field generator 3 and the second magnetic field generator 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 to be spaced apart in the first direction X within the housing 2. The second magnetic field generating unit 4 is formed to be spaced apart in the first direction X from the first magnetic field generating unit 3. The first magnetic field generating unit 3 and the second magnetic field generating unit 4 are provided within a 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 a first shield member 5 described below is not present.

[0019] In the embodiment of the present disclosure, each of the first magnetic field generation unit 3 and the second magnetic field generation unit 4 is schematically formed along a plane intersecting with the first direction X. In the embodiment of the present disclosure, the plane intersecting with the first direction X is the Y-Z plane that includes both the second direction Y perpendicular to the first direction X and the third direction Z perpendicular to the first direction X and the second direction Y.

[0020] The first shield member 5 is disposed between the first magnetic field generation unit 3 and the second magnetic field generation unit 4 in the first direction X. The first shield member 5 is disposed close to the first magnetic field generation unit 3 in the first direction X. In other words, the first shield member 5 is disposed apart from the first magnetic field generation unit 3 in the first direction X and within a predetermined range of proximity dimension D relative to the first magnetic field generation unit 3.

[0021] Here, the proximity dimension D is preferably set to, for example, 0.5 mmD≦5 mm. By arranging the first shield member 5 close to the first magnetic field generator 3 within this proximity dimension D range, it is possible to prevent the magnetic field generated by the first magnetic field generator 3 from extending to the second magnetic field generator 4, and prevent the magnetic field generated by the second magnetic field generator 4 from extending to the first magnetic field generator 3. If the proximity dimension D is larger than the above range, the shielding performance of the first shield member 5 is rapidly reduced. On the other hand, if the proximity dimension D is smaller than the above range, the first shield member 5 and the first magnetic field generator 3 are likely to come into contact with each other during assembly, reducing the ease of assembly.

[0022] The first shield member 5 is made of a conductive material such as a conductive metal. The first shield member 5 is formed in a plate shape extending along a plane intersecting the first direction X. The first shield member 5 has a first conductive portion 51 having an opening 52 in its center when viewed from the first direction X. The first conductive portion 51 is formed so that at least a portion of it overlaps with the first magnetic field generator 3 when viewed from the first direction X. In an embodiment of the present disclosure, the first conductive portion 51 is formed so that its entirety overlaps with the first magnetic field generator 3 when viewed from the first direction X. For this purpose, it is preferable that the opening 52 has the same shape and size as the inner peripheral edge 3s of the first magnetic field generator 3, which extends in a loop shape, when viewed from the first direction X. Furthermore, it is preferable that the outer peripheral edge 5t of the first shield member 5 is positioned outward relative to the outer peripheral edge 3t of the first magnetic field generator 3 when viewed from the first direction X.

[0023] The first conductive portion 51 does not have to entirely overlap the first magnetic field generator 3 when viewed from the first direction X. The first conductive portion 51 may be formed so that only a portion of it overlaps the first magnetic field generator 3 when viewed from the first direction X. For example, the opening 52 may be formed so as to be located inside or outside the inner peripheral edge 3s of the first magnetic field generator 3 in a direction intersecting the first direction X. For example, the outer peripheral edge 5t of the first conductive portion 51 may be formed so as to be located inside the outer peripheral edge 3t of the first magnetic field generator 3 in a direction intersecting the first direction X. Furthermore, in the first conductive portion 51, the first extension portion 51a extending in the second direction Y and the second extension portion 51b extending in the third direction Z each preferably have a width intersecting the extension direction of 1 mm or more. Furthermore, 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 a current flows through the first conductive portion 51 due to a magnetic field is suppressed.

[0024] (Effects) In the electronic device 1A configured as described above, the first shielding member 5 is provided between the first magnetic field generating unit 3 and the second magnetic field generating unit 4. The first conductive portion 51 of the first shielding member 5 has the opening 52, thereby suppressing an increase in weight. At least a portion of the first conductive portion 51 overlaps with the first magnetic field generating unit 3 when viewed from the first direction X, and is provided within the range of the proximity dimension D relative to the first magnetic field generating unit 3, thereby providing an effective shielding effect against magnetic field coupling between the first magnetic field generating unit 3 and the second magnetic field generating unit 4. As a result, a sufficient shielding effect against magnetic field coupling can be obtained while suppressing an increase in weight.

[0025] In the above embodiment, the first conductive part 51 entirely overlaps the first magnetic field generation part 3 when viewed from the first direction X. This makes it possible to further enhance the shielding effect of the first shield member 5.

[0026] Furthermore, in the above embodiment, the first magnetic field generation unit 3 and the second magnetic field generation unit 4 are formed along a plane intersecting the first direction X. As a result, the first magnetic field generation unit 3, the second magnetic field generation unit 4, and the first shield member 5 disposed between the first magnetic field generation unit 3 and the second magnetic field generation unit 4 are arranged in parallel. This allows the first shield member 5 to be arranged in close proximity and facing each other over the entire circumference of the loop-shaped first magnetic field generation unit 3. Therefore, the shielding effect provided by the first shield 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, components common to the first embodiment will be denoted by the same reference numerals in the drawings, and descriptions thereof will be omitted. The second embodiment differs from the first embodiment in that it includes a second shielding member.

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

[0029] An electronic device 1B according to an embodiment of the present disclosure includes a second shield member 6 in addition to the configuration of the electronic device 1A described in the first embodiment. The second shield member 6 is disposed between the first magnetic field generators 3 in the first direction X. The second shield member 6 is disposed close to the second magnetic field generators 4 in the first direction X. In other words, the second shield member 6 is spaced apart from the second magnetic field generators 4 in the first direction X and is disposed within a predetermined proximity dimension D relative to the second magnetic field generators 4.

[0030] By positioning the second shielding member 6 close to the second magnetic field generating unit 4 within the range of the proximity dimension D, the magnetic field generated by the second magnetic field generating unit 4 is prevented from extending to the first magnetic field generating unit 3 side, and the magnetic field generated by the first magnetic field generating unit 3 is prevented from extending to the second magnetic field generating unit 4 side.

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

[0032] (Effects) In the electronic device 1B configured as described above, as in 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. This makes it possible to obtain a sufficient shielding effect against magnetic field coupling while suppressing weight increase. Furthermore, the electronic device 1B of this embodiment includes a second shield member 6. The second conductive portion 61 of the second shield member 6 has an opening 62, thereby suppressing weight increase. At least a portion of the second conductive portion 61 overlaps with the second magnetic field generation unit 4 when viewed from the first direction X, and is provided within the range of proximity dimensions relative to the second magnetic field generation unit 4. This makes it possible to obtain a sufficient shielding effect against magnetic field coupling while suppressing weight increase.

[0033] (Other Embodiments) Although the embodiments of the present disclosure have been described above in detail with reference to the drawings, the specific configurations are not limited to these embodiments and include design changes and the like within the scope of the gist of the present disclosure. Note that, although the first magnetic field generation unit 3 and the second magnetic field generation unit 4 have been mentioned in the above embodiments, as described above, the configurations thereof are merely shown schematically, and therefore the specific configurations thereof can be changed as appropriate depending on the actual configuration of the device body.

[0034] (Study Example) A simulation study was conducted on the configuration described in the second embodiment, and the results are shown below. A model as shown in FIG. 3 was used as an example. For comparison, a model M1 was prepared (Comparative Example 1) in which the first shield member 5 and the second shield member 6 were not provided between the first magnetic field generation unit 3 and the second magnetic field generation unit 4, as shown in FIG. 4. Also for comparison, a model M2 was prepared (Comparative Example 2) in which a shield member 9 made of a conductive material was provided at a position intermediate the first magnetic field generation unit 3 and the second magnetic field generation unit 4, dividing the interior of the housing 2 into one side and the other side in the first direction X, as shown in FIG. 5.

[0035] A simulation was performed to supply a direct current of the same current value to each model of the example, comparative example 1, and comparative example 2, and the magnetic coupling strength between the first magnetic field generating unit 3 and the second magnetic field generating unit 4 was calculated. As a result, the magnetic coupling strength was 0.178 (nH) in comparative example 1, which did not include the first shield member 5 and the second shield member 6, while the magnetic coupling strength was 0.072 (nH) in comparative example 2, which included the shield member 9. This confirmed that the shielding effect against magnetic coupling provided by the shield member 9 was achieved. In contrast, the magnetic coupling strength was 0.073 (nH) in the example, which included the first shield member 5 and the second shield member 6. This confirmed that the first shield member 5 and the second shield member 6, which were lighter due to the provision of the openings 52 and 62, also achieved a shielding effect against magnetic coupling equivalent to that of the shield member 9.

[0036] <Additional Notes> The electronic devices 1A and 1B described in the respective embodiments can be understood, for example, as follows.

[0037] (1) The electronic devices 1A and 1B according to a first aspect include a first magnetic field generating unit 3, in which an electric path through which a current flows when a current is applied is formed in a loop shape that generates a magnetic field; a second magnetic field generating unit 4, which is spaced apart from the first magnetic field generating unit 3 in a first direction X and in which an electric path through which a current flows when a current is applied is formed in a loop shape that generates a magnetic field; and a first shielding member 5, which is arranged within a predetermined proximity dimension D from the first magnetic field generating unit 3, wherein the first shielding member 5 is made of a conductive material and has a first conductive portion 51 having an opening 52 in its center when viewed from the first direction X, and the first conductive portion 51 is formed so that at least a portion of it overlaps with the first magnetic field generating unit 3 when viewed from the first direction X.

[0038] In the electronic devices 1A and 1B, a first shielding member 5 is provided between the first magnetic field generating unit 3 and the second magnetic field generating unit 4. The first conductive portion 51 of the first shielding member 5 has an opening 52, which prevents an increase in weight. At least a portion of the first conductive portion 51 overlaps with the first magnetic field generating unit 3 when viewed from the first direction X, and is provided within a proximity dimension range relative to the first magnetic field generating unit 3, thereby achieving a sufficient shielding effect against magnetic field coupling. As a result, a sufficient shielding effect against magnetic field coupling can be obtained while preventing 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), in which the first conductive portion 51 is formed so that its entirety overlaps with the first magnetic field generating portion 3 when viewed from the first direction X.

[0040] As a result, when viewed from the first direction X, the entire first conductive portion 51 overlaps with the first magnetic field generating portion 3, thereby further enhancing the shielding effect of the first shielding member 5.

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

[0042] As a result, the first magnetic field generating unit 3, the second magnetic field generating unit 4, and the first shielding member 5 arranged between the first magnetic field generating unit 3 and the second magnetic field generating unit 4 are arranged in parallel. This allows the first shielding members 5 to be arranged closely facing each other around the entire circumference of the loop-shaped first magnetic field generating unit 3. The shielding effect of the first shielding member 5 can be efficiently exerted.

[0043] (4) The electronic device 1B according to a fourth aspect is any one of the electronic devices 1B of (1) to (3), and further includes a second shielding member 6 arranged within a predetermined proximity dimension D relative to the second magnetic field generating unit 4, the second shielding member 6 being made of a conductive material and having a second conductive portion 61 having an opening 62 in the center when viewed from the first direction X, and the second conductive portion 61 being formed so that at least a portion thereof overlaps with the second magnetic field generating unit 4.

[0044] As a result, in addition to the first shielding member 5, a second shielding member 6 is provided between the first magnetic field generating unit 3 and the second magnetic field generating unit 4. The second conductive portion 61 of the second shielding member 6 has an opening 62, which prevents an increase in weight. At least a portion of the second conductive portion 61 overlaps with 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 relative to the second magnetic field generating unit 4, thereby enhancing the shielding effect against magnetic field coupling. As a result, an even more sufficient shielding effect against magnetic field coupling can be obtained while preventing an increase in weight.

[0045] 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.

[0046] DESCRIPTION OF REFERENCE NUMERALS 1A, 1B...Electronic device 2...Housing 3...First magnetic field generating section 3s...Inner peripheral edge 3t...Outer peripheral edge 4...Second magnetic field generating section 5...First shielding member 5t...Outer peripheral edge 6...Second shielding member 9...Shielding member 51...First conductive section 51a...First extension section 51b...Second extension section 52...Opening 61...Second conductive section 62...Opening D...Proximity dimension

Claims

1. An electronic device comprising: a first magnetic field generating unit, the electric path through which current flows when energized being formed into a loop shape that generates a magnetic field; a second magnetic field generating unit, the second magnetic field generating unit being spaced apart in a first direction from the first magnetic field generating unit, the electric path through which current flows when energized being formed into a loop shape that generates a magnetic field; and a first magnetic shielding member arranged within a predetermined proximity dimension range of the first magnetic field generating unit, the first magnetic shielding member being formed from a conductive material and having a first conductive portion having an opening in the center when viewed from the first direction, and the first conductive portion being formed so that at least a portion of it overlaps with the first magnetic field generating unit when viewed from the first direction.

2. The electronic device according to claim 1, wherein the first conductive portion is formed so that its entirety overlaps with the first magnetic field generating portion when viewed from the first direction.

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

4. The electronic device according to claim 1 or 2, further comprising a second magnetic shielding member arranged within a predetermined proximity dimension range with respect to the second magnetic field generating unit, the second magnetic shielding member being formed from a conductive material and having a second conductive portion with an opening in the center when viewed from the first direction, and the second conductive portion being formed so that at least a portion of it overlaps with the second magnetic field generating unit.

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