WO2020066563A1

WO2020066563A1 - Coil device and electrical junction box

Info

Publication number: WO2020066563A1
Application number: PCT/JP2019/035327
Authority: WO
Inventors: 一輝増田
Original assignee: 株式会社オートネットワーク技術研究所; 住友電装株式会社; 住友電気工業株式会社
Priority date: 2018-09-28
Filing date: 2019-09-09
Publication date: 2020-04-02
Also published as: JP2020053625A

Abstract

A coil device 20 that comprises: a core 30 that is a magnetic body that has a pair of facing walls 32A, 32B that are arranged so as to face and a plurality of leg parts 40 that protrude toward the sides toward which the facing walls 32A, 32B face at different areas of the facing walls 32A, 32B; and a plurality of windings 21 that are wound on the plurality of leg parts 40. In an area that is between the adjacent plurality of windings 21, the facing walls 32A, 32B of the coil device 20 comprise a reduced-diameter part 38 at which the cross-sectional area of the facing walls 32A, 32B in a cross-section that is orthogonal to the direction of the magnetic flux ϕ1 that is generated inside the facing walls 32A, 32B as a result of energization of the windings 21 is smaller.

Description

Coil device and electrical junction box

技術 This specification discloses a technique relating to a coil device and an electric junction box.

Conventionally, a coil device in which a plurality of windings are wound around a magnetic core is known. In the coupling transformer of Patent Literature 1, windings are wound around two cores arranged to face each other. Specifically, each core has an E-shape having a central leg and a pair of side legs projecting from the plate-shaped portion to the other core side. A gap is provided.

Japanese Patent Application Laid-Open No. 2013-198211 (FIG. 7)

By the way, if it is attempted to shorten the length of both sides of each core of the above-described coupling transformer to reduce the overall height, the distance between the plate-shaped portions of the two cores facing each other becomes short, and the gap portion is reduced. Leakage magnetic flux is likely to be generated at locations where it is not provided. When the leakage flux increases, the magnetic flux density of the center leg increases, and there is a concern that magnetic saturation occurs in the core.

技術 The technology described in this specification has been completed based on the above circumstances, and aims to suppress magnetic saturation while suppressing an increase in the size of the coil device.

A coil device described in the present specification is a magnetic body including a pair of opposed walls arranged to face each other and a plurality of legs protruding to a side where the opposed walls face each other in different regions of each of the opposed walls. And a plurality of windings wound around the plurality of legs, wherein the winding is provided in a region between the plurality of adjacent windings of the opposing wall. And a small-diameter portion having a reduced cross-sectional area in a cross section that intersects with the direction of the magnetic flux generated inside the opposed wall due to the current supply.
According to this configuration, the portion where the cross-sectional area of the opposing wall of the core is reduced increases the magnetic resistance, so that the magnetic saturation can be suppressed.

The coil device described in the present specification includes a magnetic core having a pair of opposing walls arranged opposite to each other and a plurality of legs protruding in a direction in which the pair of opposing walls are opposed to each other; And a plurality of windings wound around the legs of the coil device, wherein the opposing wall has a notch cut out so that a path of a magnetic flux passing between the pair of opposing walls becomes longer. Have.
According to this configuration, since the path of the magnetic flux passing outside the core is extended by the cutout portion, the magnetic resistance increases, and the magnetic saturation can be suppressed.

The following embodiments are preferable as embodiments of the technology described in this specification.
The notch is provided at a peripheral edge of the opposing wall.
The notch is formed in a region between the adjacent windings.
The notch is formed on the surface on the winding side.

The winding is a flat wire having a turn portion extending in an annular shape and a terminal portion protruding outward from an end of the turn portion and connectable to the outside.

The terminal portion is disposed inside a position on an outer periphery of the turn portion that intersects a first direction connecting central axes of the plurality of windings.

対向 The opposing wall is sized to include the entire area of the turn part.

電気 An electric connection box including the coil device, a circuit board connected to the winding, and a case covering the coil device and the circuit board.

電流 The plurality of windings are configured to flow currents having different phases.

According to the technology described in this specification, it is possible to suppress magnetic saturation while suppressing an increase in the size of the coil device.

Longitudinal sectional view showing the electric junction box of the first embodiment. Top view showing coil device Front view showing coil device Plan view showing a state where a winding is assembled to one of the divided members Plan view showing one divided member Front view showing core FIG. 4 is a plan view showing a coil device according to a second embodiment. FIG. 4 is a plan view showing a coil device according to a third embodiment. AA sectional view of FIG. Sectional drawing which shows the coil device as a comparative example of FIG. Sectional drawing which shows the coil device of Embodiment 4. Plan view showing one divided member Sectional drawing which shows the coil device of Embodiment 5. Plan view showing one divided member

<First embodiment>
Embodiment 1 will be described with reference to FIGS.
The electric connection box 10 is disposed on a power supply path between a power supply such as a battery of a vehicle and a load including a vehicle-mounted electric component such as a lamp and a wiper and a motor, and is used for a DC-DC converter and an inverter, for example. be able to. Although the electric junction box 10 can be arranged in any orientation, the following description will be made assuming that the X direction in FIG. 2 is forward, the Y direction is left, and the Z direction in FIG. 1 is upward.

As shown in FIG. 1, the electric connection box 10 includes a circuit board 11, a coil device 20 mounted on the circuit board 11, and a case 13 that houses the circuit board 11 and the coil device 20. The circuit board 11 has a rectangular shape, for example, and uses a printed board in which a conductive path made of a copper foil or the like is formed by a printed wiring technique on an insulating plate made of an insulating material. Note that a circuit board may be configured by attaching a bus bar made of a metal plate material such as copper or a copper alloy to a printed board with an adhesive or the like. A plurality of terminal insertion holes 12 through which the respective terminal portions 23 of the coil device 20 are inserted are formed in the circuit board 11, and the respective terminal portions 23 are soldered while being inserted into the terminal insertion holes 12. It is electrically connected to the conductive path of the circuit board 11.

As shown in FIGS. 3 and 4, the coil device 20 includes two (plural) windings 21 and a magnetic core 30 around which the two windings 21 are wound. Each winding 21 is made of, for example, copper or a copper alloy, and is a so-called edgewise coil, and has a flat rectangular wire having a flat rectangular cross section, and has a central axis such that the short side is an inner diameter surface and an outer diameter surface. It is formed by spirally winding around A1 and A2, and a coating such as enamel is formed on the outer surface. The winding 21 has an annular turn portion 22 and a pair of terminal portions 23 connected to the outside. The number of turns of the turn portion 22 is generally two in this embodiment, but is not limited to this, and the number of turns can be changed as appropriate.

The pair of terminal portions 23 are connected to the turn portion 22, are led out of the core 30, and are bent in an L-shape at the front side of the core 30. 12 and soldered. As shown in FIG. 4, the inner terminal part 23 of the pair of terminal parts 23 of each winding 21 is connected to a first straight line D1 passing through both the center axis A1 and the center axis A2 on the outer periphery of the turn part 22. At the intersecting position P2, it extends linearly forward in the tangential direction of the turn portion 22 (the center axis A1, A2 and the second direction D2 orthogonal to the first direction D1). The outer terminal portion 23 of the pair of terminal portions 23 is positioned such that the terminal portion 23 is located on the inner side (the other winding 21 side) of the outer periphery of the turn portion 22 at a position P1 intersecting with the first straight line D1. A bent portion 24 is provided so as to extend to the side (the direction along the tangential direction of the turn portion 22 at the position P1). The two windings 21 are arranged on the same plane in a direction inverted by 180 degrees, and when the windings 21 are energized by PWM (Pulse Width Modulation) control of a circuit formed by the circuit board 11, the two windings 21 are connected to each other. Since a current of the opposite phase flows, a magnetic flux is generated from the winding 21 in the same direction (vertical direction) of the central axes A1 and A2.

The core 30 is made of a magnetic material having a high magnetic permeability such as ferrite and has a shape that covers the outside of the winding 21. As shown in FIG. 6, the core 30 is configured by combining a pair of upper and lower split members 31 A and 31 B. I have. Each of the divided

members

31A and 31B has a pair of

opposing walls

32A and 32B arranged opposite to each other, and a pair of (plural) cylindrical first legs protruding in a direction in which the pair of

opposing walls

32A and 32B oppose each other. 40, which are integrally formed. Each of the

opposing walls

32A and 32B has a rectangular plate shape and, as shown in FIGS. 2 and 5, a winding opposing portion in a region where the winding 21 is arranged (a region inside the outer periphery of the winding 21). 33, an extension 34 extending outside the two windings 21, and a bridge 39 connecting between the regions of the two windings 21.

The extension 34 is provided at a position including the corners of the opposing

walls

32A, 32B. A second leg 35 is provided at the edge of the extension 34 (at the four corners of the pair of opposing

walls

32A, 32B) to project toward the other opposing wall 32B (32A). The second leg 35 has a pentagonal (polygonal) shape including end faces of the corners of the opposing

walls

32A and 32B, and the surface on the winding 21 side is notched.

The front and rear end surfaces (side surfaces in the direction in which the windings 21 are arranged) of the

opposed walls

32A and 32B have a large-diameter portion 37 and a cross-sectional area having a smaller width dimension (dimension in the front-rear direction) than the large-diameter portion 37. (A cross-sectional area of the XZ plane). Between the large-diameter portion 37 and the small-diameter portion 38, the area outside the two windings 21 is curved along the outer circumference of the winding 21, and is directed toward the middle side in the left-right direction (bridge 39 side). The width is gradually reduced. The bridge portion 39 is provided at an intermediate portion (between the adjacent windings 21) of the opposing

walls

32A, 32B in the left-right direction, and has a constant width dimension (dimension in the front-rear direction). The cross-sectional area (width dimension and height dimension) of the bridge portion 39 is, for example, the sum of a magnetic flux caused by a two-phase DC current difference of at least two windings 21 and a magnetic flux generated by a two-phase PWM phase difference. The cross-sectional area is not magnetically saturated. The lower limit of the cross-sectional area of the bridge 39 is, for example, a cross-sectional area that is not saturated with the AC component while securing a path of the DC component from the first leg 40 to the second leg 35 of the extension 34. .

As shown in FIG. 6, a gap between a pair of upper and lower first legs 40 protruding from upper and lower opposing

walls

32A and 32B is a first gap G1, and a pair of second upper and lower opposing

walls

32A and 32B is formed. The gap between the

legs

35, 35 is a second gap G2. The size of the first gap G1 is smaller than the size of the second gap G2.

In addition, in this embodiment, since the division member 31A and the division member 31B have a relationship in which they are not in contact with each other by providing the gap portions G1 and G2, the relative position between the division member 31A and the division member 31B is For example, a spacer made of a synthetic resin or the like is sandwiched between the divided

members

31A and 31B (for example, the gap portions G1 and G2), or a potting material (for example, a silicone resin or the like) is placed inside the core 30 (to which the winding 21 is assembled). By filling and solidifying, the space between the divided

members

31A and 31B may be maintained at a predetermined interval. The holding of the relative position between the divided

members

31A and 31B is not limited to this. For example, a positioning unit (not shown) for individually positioning both the divided member 31A and the divided member 31B with respect to the circuit board 11 and the case 13. (Shown).

The case 13 is made of metal or synthetic resin, and is configured by fitting an upper case 14 and a lower case 15 as shown in FIG. 1, and is screwed with, for example, screws (not shown).

Next, a method for manufacturing the electric junction box 10 will be described.
As shown in FIG. 4, a pair of first leg portions 40 of one core 30 are inserted into the insides of the two windings 21, and the other core 30 is opposed to the one core 30. The coil device 20 is formed by inserting the pair of first leg portions 40 of the other core 30 inside (FIG. 3).

Next, an electronic component EP (see FIG. 1) such as a field effect transistor (FET) as a switching element is surface-mounted on the circuit board 11 by, for example, reflow soldering. Further, the terminal unit 23 of the coil device 20 is inserted into the terminal insertion hole 12 of the circuit board 11, and the coil device 20 is positioned by positioning means such as a leaf spring while the coil device 20 is mounted on the circuit board 11. Then, the terminal portion 23 is soldered to the conductive path of the circuit board 11 by, for example, flow soldering. By housing the circuit board 11 on which the coil device 20 is mounted between the upper case 14 and the lower case 15, the electric connection box 10 (FIG. 1) is formed. In order to hold the position of the coil device 20 in the electric connection box 10, for example, a holding piece (not shown) made of a metal plate for holding the coil device 20 with an elastic force is fixed to the case 13, and the elasticity of the holding piece is adjusted. The coil device 20 may be pressed against the circuit board 11 by force.

According to the present embodiment, the following operations and effects are achieved.
The coil device 20 includes a pair of opposing

walls

32A and 32B arranged opposite to each other, and a plurality of first legs 40 projecting to the side where the opposing

walls

32A and 32B oppose each other in different regions of the opposing

walls

32A and 32B. And a plurality of windings 21 wound around the plurality of first legs 40. The coil device 20 includes a plurality of adjacent windings among the opposing

walls

32A and 32B. In a region between the wires 21, a small-diameter portion 38 having a reduced cross-sectional area of a cross section orthogonal (intersecting) to the direction of the magnetic flux Φ1 generated inside the opposed walls 32 A and 32 B due to the conduction of the plurality of windings 21 is provided.
When the distance between the upper and lower opposing

walls

32A, 32B is reduced to reduce the height in the direction of the central axes A1, A2 of the winding 21, magnetic saturation occurs in the core due to the leakage magnetic flux between the opposing

walls

32A, 32B. There is a concern about defects such as current. According to the shape of the core 30 according to the present embodiment, the magnetic resistance R is equal to L / μS (L is the length of the magnetic circuit, S is the cross-sectional area, and μ is the magnetic permeability) [A / Wb]. Therefore, the magnetic resistance of the small-diameter portion 38 in which the cross-sectional area of the opposing

walls

32A and 32B of the core 30 is reduced can be increased. Therefore, magnetic saturation can be suppressed due to an increase in magnetic resistance, and defects such as overcurrent can be suppressed.

The winding 21 is a flat wire including a turn portion 22 extending annularly and a terminal portion 23 protruding outward from an end of the turn portion 22 and connectable to the outside.
By doing so, it is possible to reduce the size in the direction of the central axes A1 and A2 while increasing the allowable current for the winding 21.

Further, the terminal portion 23 is disposed inside a position P1 on the outer periphery of the turn portion 22 that intersects the first direction D1 connecting the central axes A1 and A2 of the plurality of windings 21.
In this way, a space for disposing the second leg 35 in the extension 34 can be formed.

The pair of (plural) windings 21 are configured to flow currents having opposite phases (currents having different phases).
By doing so, the magnetic flux of the DC component passing through the pair of first legs 40 can be canceled. In addition, since the DC component of the magnetic flux mainly passes through the closed magnetic path passing through the second leg 35, the magnetic saturation can be suppressed by providing the second gap G2.

<Embodiment 2>
Next, a second embodiment will be described with reference to FIG. The coil device 50 according to the second embodiment is different from the coil device 20 according to the first embodiment in that the front and rear end surfaces of the pair of opposing

walls

32A and 32B have different shapes. In the following, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The large-diameter portion 37 at the front and rear end surfaces of the pair of opposing walls 51 and the small-diameter portion 52 whose cross-sectional area is reduced by making the width dimension (dimension in the front-rear direction) of the opposing wall 51 smaller than the large-diameter portion 37. A linear inclined surface is formed between. Thereby, part of the outer periphery of the turn portion 22 of the two windings 21 is exposed above and below the pair of opposing walls 51. The cross-sectional area and the length of the bridge portion 53 provided in the small-diameter portion 52 are the same as the cross-sectional area and the length of the bridge portion 39 of the first embodiment. The value may be different from one bridge portion 39.

<Embodiment 3>
Next, a third embodiment will be described with reference to FIGS. The coil device 60 of the third embodiment has a pair of

opposed walls

61A and 61B provided with

cutouts

62A and 62B at the peripheral edges. In the following, the same components as those in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

切 Notch portions

62A, 62B are provided at the peripheral portions of the opposing

walls

61A, 61B, with four end surfaces cut out. The

notches

62A and 62B are formed continuously over the entire circumference of the opposing

walls

61A and 61B except for the four corners 63 where the

second legs

35 and 35 are formed, and the rectangular opposing wall 61A is formed. , 61B, the notch 62B is formed in a path longer than the notch 62A. The

notches

62A and 62B extend the path through which the magnetic flux leaking from the end surfaces of the opposing

walls

61A and 61B passes through the air, thereby increasing the magnetic resistance. The dimensions of the

notches

62A and 62B are set to dimensions that do not cause magnetic saturation due to magnetic flux generated when a DC current of the same value is applied to each phase of at least two windings 21.

According to the third embodiment, the following operations and effects are achieved.
The coil device 60 includes a magnetic core 30 having a pair of opposing

walls

61A and 61B disposed opposite to each other and a plurality of first legs 40 projecting in a direction in which the pair of opposing

walls

61A and 61B oppose each other. , A plurality of windings 21 wound around the plurality of first legs 40, wherein the opposing

walls

61A, 61B have a path of the magnetic flux Φ1 passing between the pair of opposing

walls

61A, 61B. Have

notches

62A and 62B cut out so as to be longer.
As shown in FIG. 10, when the distance between the pair of opposing

walls

65A, 65B is short, the magnetic flux ΦBB passing through the opposing

walls

65A, 65B generates a leakage magnetic flux ΦBA between the pair of opposing

walls

65A, 65B. There is a concern that the magnetic flux ΦB increases the magnetic flux density of the main magnetic flux ΦA passing through the first leg 40, and magnetic saturation occurs. On the other hand, according to the present embodiment, as shown in FIG. 9, the path of the magnetic flux Φ1 passing through the air outside the

opposed walls

65A and 65B by the

notches

62A and 62B is lengthened by the

notches

62A and 62B. As a result, the magnetic resistance of the magnetic flux Φ1 (the dotted arrow in FIG. 9) passing outside the opposed walls 65A and 65B0 increases, so that the magnetic saturation can be suppressed.

<Embodiment 4>
Next, a fourth embodiment will be described with reference to FIGS. The coil device 70 according to the fourth embodiment differs from the coil device 70 according to the third embodiment in that

notches

72A and 72B are provided on the opposing surfaces of the pair of opposing

walls

71A and 71B so that the thickness of the perimeters of the opposing

walls

71A and 71B. Is made thinner. In the following, the same components as those of the third embodiment are denoted by the same reference numerals, and description thereof is omitted.

切 As shown in FIG. 12,

cutouts

72A and 72B are formed in the periphery of the opposing

walls

71A and 71B on the opposing surface side. The

cutouts

72A and 72B are continuous over the entire periphery of the

opposed walls

71A and 71B except for the four corners 63 where the

second legs

35 and 35 are formed, similarly to the

cutouts

62A and 62B of the third embodiment. Is formed. The depths (vertical dimensions) of the

notches

72A and 72B are set to values that do not cause magnetic saturation due to magnetic resistance when a DC current having the same value is applied to at least two phases of the two windings 21.

According to the present embodiment, as shown in FIG. 11, the path of the magnetic flux Φ1 passing through the air outside the opposing

walls

71A, 71B (core) is extended by the

notches

72A, 72B by the

notches

72A, 72B. Accordingly, the magnetic resistance of the magnetic flux Φ1 (the portion indicated by the dotted arrow in FIG. 11) passing outside the opposing

walls

71A and 71B increases, so that the magnetic saturation can be suppressed.

<Embodiment 5>
Next, a fifth embodiment will be described with reference to FIGS. In the coil device 80 according to the fifth embodiment, the range of the notch 82 that cuts the pair of

opposed walls

81A and 81B from the fourth embodiment is a region between the two windings 21. In the following, the same components as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 14, the notch 82 formed on the surface of the pair of

opposed walls

81A and 81B on the side of the winding 21 extends in a band shape in the front-back direction (the direction orthogonal to the direction in which the two windings 21 are arranged). The notch 82 has a notch on the opposite surface side to reduce the thickness dimension, and a left and right end of the notch 82 is formed with a stepped portion 82 A that continues from the opposing surface 81 C to the bottom surface of the notch 82. This increases the distance between the bottom surfaces of the notches 82 in the upper and lower opposing

walls

81A and 81B, so that the magnetic resistance of the magnetic flux passing between the bottom surfaces of the notches 82 can be increased. The depth (vertical dimension) and size (area) of the notch 82 are set to values that do not cause magnetic saturation due to magnetic resistance when the same value of DC current is applied to each phase of at least two windings 21. You.

According to the present embodiment, as shown in FIG. 13, the path of the magnetic flux Φ1 passing through the air between the opposing

walls

81A and 81B (core) by the notch 82 is equal to the depth cut by the upper and lower notches 82. By increasing the length, the magnetic resistance of the magnetic flux Φ1 (the portion indicated by the dotted line in FIG. 13) passing between the opposing

walls

81A and 81B increases, so that the magnetic saturation can be suppressed.

<Other embodiments>
The technology described in this specification is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the technology described in this specification.
(1) The winding 21 is an edgewise coil, but is not limited to this. For example, the winding 21 formed by winding a wire (a round wire or the like) or a pattern winding 21 may be laminated on a laminated substrate. Further, although two windings 21 are provided in the coil device, three or more windings 21 may be provided in the coil device. Further, for example, when there are three windings 21, the phase of the switching cycle of each winding 21 by PWM control may be different by 120 degrees.

(2) The opposed wall has a rectangular shape, but is not limited to this. For example, a shape having a curved surface on the outer periphery such as a polygon other than a rectangle or an ellipse may be used. Further, the shapes of the small diameter portion and the notch portion are not limited to the shapes of the above embodiment, and can be appropriately changed.

(3) Although the bent portion 24 is provided between the turn portion 22 and the terminal portion 23, the bent portion 24 is not provided, and both of the pair of terminal portions 23 have a shape extending in a tangential direction on the outer periphery of the turn portion 22. Is also good. In addition, although the terminal portion 23 is L-shaped, the terminal portion 23 is not limited thereto, and may be a linearly extending terminal portion 23. In this case, for example, the coil device 20 stands upright (upright) with respect to the circuit board 11. May be arranged.

(4) The small-diameter portion and the notch in the above embodiment may be configured to include any combination of a plurality of notches, the small-diameter portion and the notch. For example, a cutout may be formed on the side of the opposite wall on which the small-diameter portion is not formed, and one opposed wall may include a small-diameter portion and a cutout.

10: Electric connection box 11: Circuit board 13:

Case

20, 50, 60, 70, 80: Coil device 21: Winding 22: Turn part 23: Terminal part 24: Bend part 30:

Core

31A, 31B: Dividing

member

32A , 32B, 51, 61A, 61B, 71A, 71B, 81A, 81B: opposing wall 34: extension 35: second leg 37: large diameter 38, 52: small diameter 39, 53: bridge 40: 1st leg (leg)
62A, 62B, 72A, 72B, 82: Notch G1: First gap G2: Second gap

Claims

A magnetic core having a pair of opposing walls arranged opposite to each other and a plurality of legs protruding to a side where the opposing walls oppose each other in different regions of the opposing walls,
A plurality of windings wound around the plurality of legs, a coil device comprising:
In the area between the adjacent windings of the opposing wall, a small-diameter portion having a reduced cross-sectional area in a cross section that intersects with a direction of a magnetic flux generated inside the opposing wall by energization of the windings is provided. Equipped coil device.
A magnetic core having a pair of opposed walls arranged opposite to each other and a plurality of legs protruding in a direction in which the pair of opposed walls are opposed to each other;
A plurality of windings wound around the plurality of legs, a coil device comprising:
A coil device, wherein the opposing wall has a notch cut out such that a path of a magnetic flux passing between the pair of opposing walls becomes longer.
The coil device according to claim 2, wherein the notch is provided at a peripheral edge of the opposing wall.
The coil device according to claim 3, wherein the notch is formed in a region between the adjacent windings.
The coil device according to claim 3, wherein the notch is formed on a surface on the winding side.
The said winding is a flat wire provided with the turn part extended in an annular shape, and the terminal part which protrudes outward from the edge part of the said turn part, and can be connected with the exterior, The Claims 1 to 5 characterized by the above-mentioned. The coil device according to claim 1.
The coil device according to claim 6, wherein the terminal portion is disposed inside a position on an outer periphery of the turn portion that intersects a first direction connecting central axes of the plurality of windings.
The coil device according to claim 6, wherein the opposed wall has a size including an entire area of the turn portion.
A coil device according to any one of claims 1 to 8,
A circuit board connected to the winding,
An electric connection box, comprising: a case that covers the coil device and the circuit board.
The electrical junction box according to claim 9, wherein currents having different phases flow through the plurality of windings.