JP2018117012A - Multi-stage coil and circuit component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil capable of miniaturizing a circuit component.SOLUTION: A multi-stage coil comprises: at least two or more winding parts that include a winding part formed by winding a winding and a connection part extended from the winding part; and a magnetic core including an axis part distributed along an axial direction of the winding part in a center of a radial direction of the winding part and a wall part extended along the radial direction of the winding part. The plurality of coils is arranged along the axial direction. The magnetic core comprises: a pair of end parts distributed in both end parts in the axial direction of the plurality of coils; and intermediate cores distributed between the plurality of adjacent coils one by one.SELECTED DRAWING: Figure 13

Description

  The technology disclosed in the present specification relates to a multistage coil and a circuit structure to which the multistage coil is connected.

  Conventionally, a circuit structure in which various electronic components are mounted on a circuit board having a conductive circuit is known. In such a circuit structure, a coil may be used as an electronic component mounted on a circuit board.

Japanese Patent Laying-Open No. 2015-104183

  However, since the coil is relatively large, it is necessary to provide a wide area for mounting the coil on the circuit board, and it is necessary to route the conductive circuit while avoiding that area. In particular, when a plurality of coils are mounted, there is a problem that the circuit board, and thus the circuit structure, is enlarged.

  The technology disclosed in this specification has been completed based on the above-described circumstances, and aims to reduce the size of a circuit structure.

  The technology disclosed in the present specification includes at least two or more coils each having a winding part formed by winding a winding, and a connection part extending from the winding part, and the winding A plurality of magnetic cores including: a shaft portion disposed along an axial direction of the winding portion at a center in a radial direction of the winding portion; and a wall portion extending along the radial direction of the winding portion. The coils are arranged along the axial direction, and the magnetic core is between a pair of end cores arranged at both ends in the axial direction of the plurality of coils and the plurality of adjacent coils. It is the multistage coil provided with the intermediate core arranged one by one.

  According to such a configuration, a plurality of coils conventionally connected individually to the circuit board can be collectively handled as one multistage coil. That is, the number of parts can be reduced. Further, in the conventional arrangement in which a plurality of individual coils are arranged side by side, the magnetic core of one coil and the magnetic core of the other coil are arranged between adjacent coils. Since it can be set as the form which shares the magnetic core of an adjacent coil, the arrangement | positioning area of a coil can be made small compared with the case where a several separate coil is arranged. That is, the circuit structure to which the coil is connected can be reduced in size.

  The multistage coil may have the following configuration.

  The multi-stage coil may be housed in a coil case, and the coil case may be filled with a potting material.

  According to such a configuration, air vibration due to magnetostriction is eliminated and abnormal noise is less likely to occur. Further, rattling of the multistage coil in the coil case is suppressed. Further, since it is not necessary to separately provide a holding structure for holding the multistage coil in an assembled state, the configuration can be simplified and the size can be reduced.

  The connecting portion may extend in the extending direction from the winding portion and bend in the intersecting direction intersecting the extending direction. According to such a configuration, when the intersecting direction is set in the same direction as the axial direction of the winding portion, the axial direction of the winding portion is in a vertically placed state parallel to the plate surface of the circuit board, Multistage coils can be placed on the circuit board.

  Further, the connection portion may extend from the winding portion and be bent in a crank shape. According to such a configuration, the multi-stage coil can be disposed between the pair of circuit boards in a horizontal state in which the axial direction of the winding portion is perpendicular to the plate surface of the circuit board. That is, the distance between the pair of circuit boards can be reduced as compared with the conventional one.

  Furthermore, the technology disclosed in the present specification includes a winding portion formed by winding a winding, and a connection portion extended from the winding portion, and is along the axial direction of the winding portion. A plurality of coils arranged side by side, a shaft portion arranged along the axial direction of the winding portion at the radial center of the winding portion, and along the radial direction of the winding portion A pair of end cores disposed at both ends in the axial direction of the plurality of coils, and an intermediate core disposed one by one between the plurality of adjacent coils, A multi-stage coil including a magnetic core including the circuit core is connected to the conductive circuit of the circuit board.

  According to the technique disclosed in this specification, the circuit structure can be reduced in size.

The perspective view of the coil assembly of Embodiment 1 Exploded perspective view of coil assembly Exploded perspective view of choke coil Exploded bottom view of choke coil Plan view of the intermediate core Bottom view of choke coil Top view of choke coil Choke coil front view Choke coil side view Bottom view of coil assembly without potting material Top view of coil assembly Front view of coil assembly Conceptual diagram of a circuit assembly with a coil assembly mounted The perspective view of the coil assembly of Embodiment 2. Sectional drawing of the state which connected the coil assembly of Embodiment 3 to the conductive circuit Plan view of a two-stage choke coil of another embodiment Plan view of a two-stage choke coil of another embodiment Sectional view of a state where two conventional coils are aligned and connected to a conductive circuit

<Embodiment 1>
A first embodiment will be described with reference to FIGS.

  A coil assembly 10 (an example of a multistage coil) according to the first embodiment accommodates a two-stage choke coil 11 (an example of a multistage coil) in a coil case 30 as shown in FIGS. 30 is filled with a potting material 36.

  As shown in FIGS. 3 and 4, the two-stage choke coil 11 includes a magnetic core 12 and two coils 20. The magnetic core 12 of the present embodiment is between a pair of first cores 12A (an example of an end core) and a second core 12B (an example of an end core) that are called the so-called PQ-type cores. The intermediate core 12C is combined.

  The first core 12 </ b> A and the second core 12 </ b> B include a slightly thick flat plate-like wall portion 13, a columnar shaft portion 14 protruding from the center of one surface side of the wall portion 13 to one side, and one wall portion 13. And a pair of plate-like leg portions 15 projecting in the same direction as the shaft portion 14 from a pair of side edges facing each other.

  Of the side edges of the wall portion 13, the pair of side edges where the leg portions 15 are not provided are cut out in a substantially triangular shape from the vicinity of both end portions toward the shaft portion 14. As a substantially ribbon shape (see FIG. 8). The wall portion 13 is not limited to a ribbon shape, and other shapes such as a rectangle may be used.

  The intermediate core 12C is disposed between the first core 12A and the second core 12B, and has the same shape and the same size as the wall portion 13 of the first core 12A and the second core 12B and has an equivalent thickness. From the wall portion 13C, the columnar intermediate shaft portion 14C protruding from the center of both surfaces of the intermediate wall portion 13C toward the first core 12A and the second core 12B, and a pair of side edges facing the intermediate wall portion 13C A plate-like intermediate leg portion 15C protruding toward the first core 12A and the second core 12B.

  The intermediate core 12C abuts the shaft portions 14 and 14C and the leg portions 15 and 15C with the first core 12A and the second core 12B aligned with the wall portion 13 (intermediate wall portion 13C). Are superimposed. In this state, a space is formed between the first core 12A and the intermediate core 12C, and between the intermediate core 12C and the second core 12B, and a coil 20 described later is arranged in this space. (See FIGS. 6 and 7).

  The coil 20 used in this embodiment is an edgewise coil formed by winding a rectangular wire in an edgewise shape and in an annular shape. As shown in FIG. 3, one coil 20 is wound to form both ends of a rectangular wire (referred to as connecting portions 22 </ b> A and 22 </ b> B) from both ends in the axial direction L of the winding portion 21 that is wound and forms a cylindrical shape as a whole. Are extended in the same direction (extending direction X) orthogonal to the axial direction L and in parallel with each other, and L along the axial direction L (intersecting direction Y intersecting the extending direction X). It is shaped like a letter.

  The distal end side of the flat wire is a connection end portion 23 connected to the conductive circuit. As shown in FIG. 4, the pair of connection portions 22 </ b> A and 22 </ b> B of one coil 20 extends from different heights in the axial direction L of the winding portion 21. In addition, the pair of connection portions 22 </ b> A and 22 </ b> B of one coil 20 is set to a dimension such that the tips (connection end portions 23) thereof have the same height in the axial direction L of the winding portion 21. Each of the pair of connection portions 22A and 22B (connection end portion 23) is formed with a connection hole 26 so as to be connected to the conductive circuit by bolt fastening.

  The two coils 20 are arranged one by one in the space between the first core 12A and the intermediate core 12C and between the intermediate core 12C and the second core 12B. That is, the winding portion 21 of the first coil 20A is arranged around the shaft portions 14 and 14C of the first core 12A and the intermediate core 12C, and the winding portion 21 of the first coil 20A is the intermediate core. 12C and the second core 12B are arranged around the shaft portions 14C and 14 (see FIG. 8).

  3 and 4, the winding direction of the rectangular wire of the first coil 20A on the upper side and the second coil 20B on the lower side is the same direction. Further, both ends of the flat wire of the first coil 20A are bent so that the connecting portions 22A and 22B extend upward, and both ends of the flat wire of the second coil 20B are connected to the connecting portions 22A and 22B. It is bent so as to extend downward. That is, the first coil 20A and the second coil 20B are arranged so that the winding direction of the flat wire is the same, while the connecting portions 22A and 22B face the opposite side.

  In addition, the leg portions 15 and 15C of the magnetic core 12 described above have an inner surface that follows the side edge portion of the coil 20. That is, as shown in FIG. 5 and FIG. 8, the lower side in the figure is a shape along the extending direction of both ends of the flat wire, and the upper side is a shape along the winding part 21.

  Such magnetic cores 12A, 12B, and 12C and the two coils 20A and 20B form a two-stage choke coil 11 (see FIGS. 6 to 9).

  The two-stage choke coil 11 is accommodated in the coil case 30.

  The coil case 30 is made of a synthetic resin material, and as shown in FIG. More specifically, the coil case 30 includes a pair of first side walls 32 along the outer surface of the wall portion 13 of the two-stage choke coil 11 and a pair of second side walls along the outer surface of the leg portion 15 of the two-stage choke coil 11. 33 and the bottom wall 34 of the two-stage choke coil 11 along the surface opposite to the surface from which the connecting portions 22A and 22B are extended. Among the edges of the opening 31 of the coil case 30, ribs 35 project outward from the edge on the second side wall 33 side.

  Of the pair of first side walls 32, the side edges on the rear side are notched obliquely toward the inside in the vicinity of the center along the side edges of the wall 13 of the two-stage choke coil 11 ( (See FIG. 12). Further, the region of the bottom wall 34 corresponding to the first coil 20A and the second coil 20B of the two-stage choke coil 11 swells in a cross-section arc shape toward the rear side along the outer periphery of the winding portion 21. The protruding bulging portion 34A is used (see FIGS. 11 and 12).

  Further, on the inner surface side of the bottom wall 34, a positioning protrusion (not shown) for positioning the magnetic core 12 of the two-stage choke coil 11 inserted in the coil case 30 and the first coil 20A and the second coil 20B. The portion is provided so as to protrude forward. That is, the magnetic core 12, the first coil 20A, and the second coil 20B are held at the proper assembly position in a state where the two-stage choke coil 11 is accommodated in the coil case 30 by the positioning protrusion. ing.

  As shown in FIGS. 1 and 2, the two-stage choke coil 11 includes a pair of connection portions 22 </ b> A and 22 </ b> B (four in total) of each coil 20 in the coil case 30 so as to protrude toward the outside of the opening 31. Is housed in. In this state, the outer surface of the magnetic core 12 is in contact with a plurality of contact ribs (not shown) provided inside the coil case 30, and there is a slight gap between the outer surface of the magnetic core 12 and the inner surface of the coil case 30. A gap is formed (see FIG. 10). A gap is also formed between the magnetic core 12 and the coil 20. These gaps are filled with a potting material 36, and the coil assembly 10 is integrated as a whole. In addition, as the potting material 36, an epoxy resin etc. can be used, for example.

  As shown in FIG. 13, the coil assembly 10 described above is disposed at a predetermined position on the circuit board 41 and is conductively connected to the conductive circuit. Details will be described later.

  Next, a method for manufacturing the coil assembly 10 and a method for attaching the coil assembly 10 to the circuit board 41 (a method for manufacturing the circuit structure 40) will be described.

  In order to manufacture the coil assembly 10, first, the two-stage choke coil 11 in an assembled state is inserted into the coil case 30 so that the two pairs of connection portions 22 </ b> A and 22 </ b> B protrude from the opening 31. The outer surface of the two-stage choke coil 11 is inserted into the back while being in contact with a contact rib (not shown) provided inside the coil case 30 and positioned by a positioning projection (not shown).

  In this state, a slight gap is formed between the outer surface of the magnetic core 12 and the inner surface of the coil case 30 and between the magnetic core 12 and the coil 20.

  When the two-stage choke coil 11 is inserted into the normal position of the coil case 30 and positioned, the coil case 30 is placed so that the opening 31 of the coil case 30 faces upward, and the potting material 36 is filled from the opening 31. The potting material 36 is filled in a gap between the two-stage choke coil 11 and the coil case 30 and a gap between the magnetic core 12 and the coil 20 and gradually hardens. Thereby, the coil assembly 10 in which the two-stage choke coil 11 is fixed in the coil case 30 is completed (see FIG. 1).

  In this state, both ends of the rectangular wire of the coil 20 are extended outward (in the same direction) from the opening 31 of the coil case 30, and the connection portions 22A and 22B of the first coil 20A and the second coil 20B are connected. The portions 22A and 22B are bent toward the opposite side. Further, the extended portion from the coil case 30 at the end of the coil 20 is firmly fixed by the potting material 36 so that the proximal end side does not move.

  Such a coil assembly 10 is connected to the circuit board 41. As shown in FIG. 13, the circuit board 41 has a plurality of bus bars 43 (an example of a conductive circuit) arranged on the back side of an insulating board on which a printed circuit (not shown) is printed on the front side. A plurality of connection holes 42 for connecting the connection portions 22 </ b> A and 22 </ b> B of the coil assembly 10 disposed on the front surface side to the bus bar 43 are provided at predetermined positions of the circuit board 41.

  In the coil assembly 10, the surface in which the connection portions 22 </ b> A and 22 </ b> B are extended faces in the direction facing the circuit board 41, i.e., the axial direction L of the winding portion 21 is parallel to the plate surface of the circuit board 41. As a state, the circuit board 41 is arranged at a predetermined position, and the connection holes 26 of the connection portions 22A and 22B (connection end portions 23) are overlapped with the connection holes 44 of the bus bar 43 exposed from the connection holes 42 of the circuit board 41. Then, the bolt 45 and the nut 46 are fastened (screwed) to connect to the bus bar 43 (conductive circuit) on the back side of the circuit board 41.

  According to the configuration of the first embodiment as described above, a plurality of coils (coils 20A and 20B of the present embodiment) that have been individually connected to the circuit board 41 are collectively formed as one coil assembly 10. It can be handled. That is, the number of parts can be reduced.

  Also, in the conventional arrangement in which a plurality of individual coils are arranged side by side, the magnetic core of one coil and the magnetic core of the other coil are arranged between adjacent coils. According to the embodiment, the magnetic core 12 (the first core 12A and the second core 12B) disposed between the adjacent coils 20A and 20B can be used as one intermediate core 12C. Therefore, the configuration is simplified as compared with the configuration in which two coils are arranged, and the coil assembly 10 can be downsized. As a result, the circuit structure 40 to which the coil assembly 10 is connected can be reduced in size.

  Further, since the two-stage choke coil 11 is accommodated in the coil case 30 and the potting material 36 is filled in the coil case 30, there is no air vibration due to magnetostriction, and noise is less likely to occur. Further, rattling of the two-stage choke coil 11 in the coil case 30 is suppressed. Further, since it is not necessary to separately provide a holding structure for holding the two-stage choke coil 11 in the assembled state, the configuration is simplified, and the coil assembly 10 and thus the circuit structure 40 can be downsized.

  Furthermore, the ends (connection portions 22A, 22B) of the coils 20A, 20B are extended from the winding portion 21 in the extending direction X, and the direction along the axial direction L of the winding portion 21 (intersection intersecting with the extending direction X). Since the structure is bent in the direction Y), the coil assembly 10 can be disposed on the circuit board 41 in a vertically placed state in which the axial direction L of the winding portion 21 is parallel to the plate surface of the circuit board 41. .

<Embodiment 2>
A coil assembly 50 according to the second embodiment will be described with reference to FIG. In the following description, only the configuration different from that of the first embodiment will be described, and the same configuration as that of the first embodiment will be denoted by the reference numeral obtained by adding 40 to the reference numeral of the first embodiment, and redundant description will be omitted. .

  The coil assembly 50 of the present embodiment is different from the first embodiment in the form of a pair of connection portions 62A and 62B extending from the winding portion 61. The connecting portions 62A and 62B are extended from both ends in the axial direction L of the winding portion 61 having a cylindrical shape as a whole in the same direction (extending direction X) and straight and parallel to each other. . A connecting hole 66 is formed through each of the tips of the connecting portions 62A and 62B so as to be connected to the conductive circuit by bolt fastening.

  The coil assembly 50 of the present embodiment is different from the first embodiment in that the coil case 70 is provided with an elastic fixing piece 76 for attaching to a coil base (not shown) provided on the circuit board side. Yes.

  The elastic fixing piece 76 has a plate shape and is integrally provided on the pair of second side walls 73 of the coil case 70. The elastic fixing piece 76 is erected vertically from the second side wall 73 toward the outside so that the plate surface thereof is parallel to the pair of first side walls 72. Each elastic fixing piece 76 is formed with a through hole 77 for attaching to a fixing hole of a coil base (not shown).

  Further, both end portions on the base end side of the elastic fixing piece 76 are integrally connected to a pair of reinforcing walls 78 extending up and down on the second side wall 73. The pair of elastic fixing pieces 76 can be slightly elastically deformed with respect to the coil case 70.

  Such a coil assembly 50 of the present embodiment is connected to the conductive circuit in a lateral state in which the connecting portions 62A and 62B are parallel to the circuit board.

<Embodiment 3>
A coil assembly 80 according to the third embodiment will be described with reference to FIG. In the following description, only the configuration different from that of the first embodiment will be described, and the same configuration as that of the first embodiment will be denoted by the reference numeral obtained by adding 70 to the reference numeral of the first embodiment, and redundant description will be omitted.

  The coil assembly 80 of the present embodiment is different from the first embodiment in the form of the end portion of the flat wire that extends from the coil 90. A pair of end portions (connecting portions 92A, 92B) of the flat wire are directed in the same direction (extending direction X) perpendicular to the axial direction L from both ends in the axial direction L of the winding portion 91 having a cylindrical shape as a whole. And extending in parallel with each other and bent into a crank shape in the same direction.

  More specifically, for example, the lower coil 90B in FIG. 15 will be described. A pair of ends (connecting portions 92A and 92B) of the flat wire are directed from the winding portion 91 to the right side (extending direction X) in the drawing. An extended portion 93 that extends in an extended manner, a stepped portion 94 that extends downward (intersection direction Y intersecting the extending direction X and axial direction L of the winding portion 91), and a stepped portion 94. And a connecting end portion 95 extending rightward (extending direction X). The height of the pair of connection end portions 95 of one coil 90 is set to be flush with each other. Each of the pair of connection end portions 95 is formed with a connection hole 96 so as to be connected to the conductive circuit by bolt fastening.

  The coil assembly 80 according to the present embodiment is electrically conductive in a horizontal state in which the connection end portion 95 is parallel to the circuit board, in other words, the axial direction L of the winding portion 91 is perpendicular to the plate surface of the circuit board. Connected to the circuit. For example, although the circuit board is omitted in FIG. 15, the pair of connection portions 92A and 92B (connection end portions 95) of the upper first coil 90A in the drawing are along the plate surface of the circuit board disposed on the upper side. It is connected to a bus bar 123A (conductive circuit). In addition, the pair of connection portions 92A and 92B (connection end portion 95) of the second coil 90B on the lower side in the drawing are connected to a bus bar 123B (conductive circuit) along the plate surface of the circuit board disposed on the lower side. Yes. That is, the coil assembly 80 is disposed between a pair of circuit boards and is connected to the bus bars 123A and 123B (conductive circuit) of the respective circuit boards.

  The connection end 95 of the first coil 90A and the connection end 95 of the second coil 90B are arranged so as to face each other, and an insulating mounting base 130 is provided between these facing surfaces. ing. A nut 126 is embedded in the mounting base 130 at a position corresponding to the connection hole 96 of the coil 90 and the connection hole 124 of the bus bar 123, and the connection hole 96 and the connection hole 124 are passed through the nut 126. By fastening the bolt 125, the coil 90 and the bus bar 123 (conductive circuit) are connected.

  According to such a coil assembly 80 of the present embodiment, the distance between a pair of circuit boards arranged in parallel to each other can be reduced as compared with the prior art. For example, FIG. 18 shows a state in which two coil assemblies having a conventional configuration are arranged side by side, but the one in FIG. 15 showing the connection state of this embodiment is a bus bar compared to the conventional one. The distance between 123A and 123B (between conductive circuits) can be reduced.

<Other embodiments>
The technology disclosed in this specification is not limited to the embodiment described with reference to the above description and drawings, and for example, the following embodiments are also included in the technical scope.

  (1) In the above embodiment, an example of a two-stage choke coil in which two coils are combined has been described. However, a multi-stage coil in which three or more coils are combined may be used.

  (2) Although the two-stage choke coil is housed in the coil case and the coil assembly is filled with the potting material in the above embodiment, the coil case and the potting material may be omitted. For example, the choke coil may be integrally fixed and held by a synthetic resin material, or an adhesive or other holding member may be used. The configuration is limited to the above embodiment as long as the magnetic core and the coil are fixed. It is not a thing.

  (3) Further, when the two-stage choke coil is accommodated in the coil case, the form of the coil case is not limited to the above-described embodiment, and can be appropriately changed, for example, the bottom wall 34 has a flat plate shape.

  (4) In the embodiment described above, the winding direction of the flat wire of the two coils is the same direction, but the winding direction may be opposite.

  (5) In the above-described embodiment, the example in which the connection portion of the two coils extends in the same direction from the winding portion has been described, but the connection portion may extend in different directions. For example, as shown in FIG. 16, it is good also as a structure by which the connection parts 142A and 142B of the two coils 140 are extended to the opposite side.

  (6) Moreover, in the said embodiment, the extension direction of a pair of connection part 22A, 22B of the one coil 20 is the same direction (extension direction X of embodiment) orthogonal to the axial direction L of the winding part 21. For example, as shown in FIG. 17, the connection portions 152 </ b> A and 152 </ b> B of the coil 150 extend in different directions orthogonal to the axial direction L, that is, cross each other in plan view. It may be a form.

  (7) In the said Embodiment 1, a pair of connection part of one coil is extended toward the same direction (extension direction X) orthogonal to the axial direction L of a winding part, and a direction along the axial direction L Although the form bent in the (intersection direction Y of Embodiment 1) is shown, the form bent in the direction intersecting the axial direction L may be used.

  (8) In the above embodiment, an example in which a PQ type core is used as the magnetic core has been shown, but other magnetic cores such as an E type core and a pot core may be used.

  (9) The coil is not limited to the edgewise coil, and other types of coils may be used.

  (10) In the above embodiment, the coil and the conductive circuit (bus bar) are electrically connected by bolt fastening. However, the present invention is not limited to this, and may be connected by soldering, for example.

10, 50, 80: Coil assembly (multi-stage coil)
11: Two-stage choke coil (multi-stage coil)
12: Magnetic core 12A: First core (end core)
12B: Second core (end core)
12C: Intermediate core 13: Wall part 14: Shaft part 20, 60, 90, 140, 150: Coil 21.61, 91: Winding part 22, 62, 92, 142, 152: Connection part 23, 95: Connection end Parts 30, 70, 110: coil case 35, 105: potting material 40: circuit component 41: circuit board 43, 123: bus bar (conductive circuit)
L: Axial direction X: Extension direction Y: Crossing direction

Claims (7)

A plurality of coils having at least two or more coils each having a winding part formed by winding a winding, and a connection part extending from the winding part;
A magnetic core having a shaft portion arranged along an axial direction of the winding portion at a center in a radial direction of the winding portion, and a wall portion extending along the radial direction of the winding portion. ,
The plurality of coils are arranged along the axial direction,
The magnetic core includes a pair of end cores disposed at both ends in the axial direction of the plurality of coils, and an intermediate core disposed one by one between the plurality of adjacent coils. Multi-stage coil. The multistage coil according to claim 1, wherein the multistage coil is housed in a coil case and filled with a potting material. 3. The multistage coil according to claim 1, wherein the connecting portion extends from the winding portion in an extending direction and is bent in a crossing direction intersecting the extending direction. The multi-stage coil according to claim 1, wherein the connection portion extends from the winding portion and is bent in a crank shape. A plurality of coils having a winding part formed by winding a winding and a connection part extending from the winding part and arranged along the axial direction of the winding part; When,
A plurality of coils, comprising: a shaft portion arranged along an axial direction of the winding portion at a center in a radial direction of the winding portion; and a wall portion extending along a radial direction of the winding portion. A multi-stage coil comprising: a magnetic core comprising a pair of end cores arranged at both ends in the axial direction; and an intermediate core arranged one by one between the plurality of adjacent coils. A circuit structure connected to the conductive circuit of the circuit board. The multi-stage coil is bent in a crossing direction in which the connection portion extends from the winding portion in the extending direction and intersects the extending direction,
The circuit structure according to claim 5, wherein the circuit configuration body is disposed on the circuit board in a vertically placed state in which the axial direction is parallel to a plate surface of the circuit board. In the multistage coil, the connection portion extends from the winding portion and is bent in a crank shape,
The circuit configuration body according to claim 5, wherein the circuit configuration body is disposed between the pair of circuit boards in a lateral state in which the axial direction is perpendicular to a plate surface of the circuit board.

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