JP2017112349A - Coil assembly and circuit structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve connection reliability of a coil assembly and a circuit board.SOLUTION: A coil assembly to be mounted on a circuit board includes a coil having a wound part consisting of a rectangular wire wound edgewise, an extension extending from the wound part in the extension direction, a step bent from the extension in a direction crossing the extension direction, and a connection bent from the step in the extension direction, and a protrusion provided at a position on the opposite side to the connection in the extension direction, and separating a part of the coil on the opposite side to the connection in the extension direction from the circuit board.SELECTED DRAWING: Figure 9

Description

  The technology disclosed in this specification relates to a coil assembly and a circuit structure.

  Conventionally, a coil assembly is known in which a coil is held between a pair of core members. For example, there is known a configuration in which a coil in which a rectangular wire is wound in an annular shape is arranged around columnar protrusions of a pair of ferrite core members called E-type cores. Both ends of the coil are terminals.

JP 2005-45119 A

  When the coil assembly is mounted on the circuit board, for example, the coil assembly is arranged at a predetermined position on the front surface side of the circuit board, and the terminal of the coil is arranged on the back surface side through the connection opening provided on the circuit board. In some cases, soldering may be applied to the bus bar. In such a case, it can be considered that the terminal of the coil led out from the coil assembly is bent toward the bus bar. In this case, a step corresponding to the thickness of the circuit board is generated between the bottom surface of the coil assembly (the surface in contact with the circuit board) and the terminal led out from the coil and bent toward the bus bar.

  However, since the coil has a winding structure and the terminal is bent, it is not easy to increase the dimensional accuracy of the terminal, and it is difficult to accurately contact the terminal with the bus bar on the back side of the circuit board. there were. In addition, since the coil has a spring characteristic in its structure, stress is easily applied to the soldered portion between the coil terminal and the bus bar due to vibrations of the vehicle, etc. There is a concern that the electrical connection reliability is lowered.

  In addition, the coil is relatively large and heavy as an electronic component mounted on the circuit board, and is likely to be displaced due to vibration during traveling. Such misalignment may also cause a decrease in the reliability of electrical connection between the coil terminal and the bus bar.

  The technology disclosed in the present specification has been completed based on the above situation, and aims to improve the connection reliability between the coil assembly and the circuit board.

  The technology disclosed in the present specification is a coil assembly disposed on a base member, which is composed of a flat wire, the winding portion in which the flat wire is wound in an edgewise manner, and the winding portion extending from the winding portion. A coil having a pair of protruding terminal portions, the terminal portion extending from a surface intersecting with the base member, and projecting toward the base member on a facing surface facing the base member. A protrusion is provided.

  Among such coil assemblies, the terminal portion is mounted on a circuit board included in the base member, and the terminal portion extends from the winding portion in the extending direction, and the extension portion extends from the extension portion. A step portion bent in the crossing direction intersecting the extending direction, and a connecting portion bent in the extending direction from the step portion, and the protruding portion includes the connecting portion and the extending portion. Provided at a position on the opposite side of the output direction, and abutting against the circuit board, the part of the coil on the opposite side of the extending direction is separated from the circuit board, There are the following effects.

  That is, according to such a configuration, when the coil assembly is placed on the circuit board, the projecting portion comes into contact with the circuit board. Then, the portion of the coil opposite to the connecting portion and the extending direction receives and holds the force in the direction away from the circuit board when the protruding portion comes into contact with the circuit board. Thereby, the force pressed against a circuit board is added to the connection part of a coil. As a result, a state in which the connection portion and the circuit board are in contact with each other is maintained. Thereby, the connection reliability of a circuit board and the coil assembly mounted in this circuit board can be improved.

  Such a coil assembly may have the following configuration.

  A magnetic core and a bobbin that contacts both the coil and the magnetic core to hold a relative position between the coil and the magnetic core, and the bobbin is provided with the protruding portion. Is preferred.

  According to such a configuration, the coil and the magnetic core can be relatively positioned by the bobbin. Further, since the projecting portion is formed on the bobbin, the number of components can be reduced as compared with the case where the projecting portion is formed on a part different from the bobbin.

  The magnetic core includes a pair of wall portions that sandwich the coil from the axial direction of the winding portion, and a pillar portion that extends from the wall portion in the axial direction and is inserted inside the winding portion. The bobbin protrudes outward from both ends of the tubular portion between the winding portion and the column portion, and extends between the winding portion and the wall portion. A pair of flanges disposed, and the flange includes a projecting portion that projects outward from the wall of the magnetic core on the opposite side of the extending direction. It is preferable that it is provided in the said overhang | projection part.

  According to said structure, the overhang | projection part protrudes on the opposite side of the extension direction rather than the wall part of a magnetic core. Since the projecting portion is formed on the projecting portion, the projecting portion is provided at a position further away from the connecting portion in the extending direction. As a result, due to the lever principle, the force in the direction of pressing the connecting portion against the circuit board becomes larger. Thereby, the connection reliability of a coil assembly and a circuit board can be improved further.

  The technology disclosed in the present specification is a circuit structure in which the above-described coil assembly is mounted on a circuit board, and the circuit board is disposed on a surface opposite to the surface on which the coil assembly is mounted. Busbars are stacked, the circuit board has an opening from which the busbar is exposed, and the connection is connected to the busbar exposed from the opening.

  A step is formed between the circuit board and the bus bar by the thickness dimension of the circuit board. The above configuration can improve the electrical connection reliability between the coil assembly and the bus bar of the circuit board even when a step is formed between the circuit board and the bus bar.

  Further, the technology disclosed in the present specification includes a rectangular wire, and a coil having a winding portion obtained by winding the flat wire in an edgewise manner and a pair of terminal portions extending from the winding portion. The terminal portion includes a coil assembly that extends from a surface intersecting with the base member, and a protruding portion that protrudes toward the base member is provided on a surface facing the base member. It is a circuit structure, Comprising: The recessed part for inserting a protrusion part in a base member is provided.

  According to such a configuration, in the state where the coil assembly is disposed on the base member, the coil assembly is prevented from being misaligned by fitting the protruding portion into the recess of the base member. Connection reliability between the substrate and the coil assembly is improved.

  Furthermore, when the adhesive is provided between the projecting portion and the recess, the positional deviation is more reliably suppressed, so that the connection reliability between the circuit board and the coil assembly is further improved.

  In addition, the said protrusion part is good also as a structure provided in the coil case which fixed the coil inside. According to such a configuration, the protruding portion can be provided with a simple structure.

  According to the technique disclosed in this specification, the connection reliability between the coil assembly and the circuit board can be improved.

The disassembled perspective view of the coil assembly of 1st Embodiment Perspective view of coil assembly Right side view of coil assembly Rear view of coil assembly Plan view of second divided bobbin body Right side view of the second divided bobbin body Rear view of the second divided bobbin body Perspective view of the back side of the second divided bobbin body Right side sectional view of the coil assembly mounted on the circuit board (circuit structure) Side sectional view of a state (circuit structure) in which the coil assembly of the second embodiment is mounted on a circuit board. Perspective view of the underside of the coil case Bottom view of coil case Side sectional view of a circuit structure according to another embodiment

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

  The coil assembly 1 according to the present embodiment includes a magnetic core 10, a coil 20 formed by winding a winding, and a bobbin 30 (see FIG. 1). For example, an electric vehicle, a hybrid vehicle, and the like. It can be used as a choke coil or the like that is provided in a DC / DC converter of a vehicle and smoothes an output voltage. In the following description, the top in FIGS. 1 and 2 is the top, the bottom is the bottom, the left front is the front, the right back is the back, the right front is the right, and the left back is the left.

(Magnetic core 10)
The magnetic core 10 is a so-called E-type core, and is formed by combining a pair of first core 10A and second core 10B having the same shape and size as shown in FIGS. The first core 10A and the second core 10B each have a rectangular thick plate-like bottom wall portion 11 (an example of a wall portion), and the bottom wall portions 11 face each other with their plate surfaces facing each other. Arranged.

  A pair of side walls 12 extending toward the mating core is provided at the edges of the pair of short sides extending in the front-rear direction of the single bottom wall 11. In addition, a columnar column portion 13 that protrudes in the same direction as the extending direction of the side wall portion 12 is provided at the center portion of the bottom wall portion 11. The rising dimension (height dimension) from the bottom wall part 11 of the side wall part 12 and the column part 13 is made equivalent.

(Coil 20)
The coil 20 of 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. 1, the coil 20 is wound from the upper end and the lower end of the wound portion 21 that forms a cylindrical shape as a whole, and both ends of the rectangular wire are directed in the same direction (forward), and It extends in parallel and is bent in a crank shape downward.

  In the following, in FIG. 1, an end portion extending from the upper side of the winding portion 21 is referred to as a first end portion 22A (an example of a terminal portion), and an end portion extending from the lower side is referred to as a second end portion 22B (terminal). Part). Further, a portion of the first end portion 22A extending from the winding portion 21 toward the front (an example of the extending direction) is connected downward to the first extending portion 23A and the first extending portion 23A (extended). A portion extending toward an example of a crossing direction that intersects with the outgoing direction is defined as a first step portion 24A, and a tip portion extending forward and connected to the first step portion 24A is defined as a first connection portion 25A. Similarly, a portion of the second end portion 22B extending forward from the winding portion 21 is connected to the second extending portion 23B and the second extending portion 23B is extended downward. A tip end portion extending to the front in a row from the stepped portion 24B and the second stepped portion 24B is referred to as a second connecting portion 25B.

  The first connection part 25A and the second connection part 25B are arranged in parallel with the first extension part 23A and the second extension part 23B. In addition, the first connection portion 25 </ b> A and the second connection portion 25 </ b> B are disposed at the same height (equal to each other), and are disposed below the lower end edge of the winding portion 21.

(Bobbin 30)
A bobbin 30 is disposed between the magnetic core 10 and the coil 20. The bobbin 30 is made of an insulating resin, and as shown in FIG. 1, a first divided bobbin body 31 and a second divided bobbin body 41 that are divided into two in a direction orthogonal to the axial direction of the winding part 21 of the coil 20. Combined.

  The first divided bobbin body 31 is disposed on the upper side of the coil 20, and a pair of sides extending in the front-rear direction among the rectangular plate-shaped first bottom wall portion 32 (an example of a flange portion) and the first bottom wall portion 32. And a pair of first side wall portions 33 extending downward from the edges of the first side wall portion 33. A first hole 34 that penetrates the plate surface is provided at the center of the first bottom wall 32.

  The length dimension in the front-rear direction of the first bottom wall portion 32 is set to be larger than the length dimension in the front-rear direction (short side side) of the bottom wall portion 11 of the magnetic core 10. The bottom wall portion 32 protrudes in the front-rear direction from the bottom wall portion 11 of the first core 10A (see FIG. 3).

  Moreover, the width dimension (length dimension in the left-right direction) of the first bottom wall portion 32 is set to be slightly smaller than the dimension between the pair of side wall portions 12 of the magnetic core 10 (inner side). The first bottom wall portion 32 is adapted to fit between the pair of side wall portions 12 of the first core 10A (see FIGS. 2 and 4).

  The height dimension of the pair of first side wall parts 33 is set to be the same as the protruding dimension of the side wall part 12 of the magnetic core 10 from the bottom wall part 11, and the lower end surface of the first side wall part 33 in the assembled state is The magnetic core 10 is flush with the lower end surface of the side wall 12 (see FIGS. 2 to 4). Further, the first hole portion 34 is set to have a slightly larger diameter than the column portion 13 so as to penetrate the column portion 13 of the magnetic core 10 (first core 10A).

  On the other hand, the second divided bobbin body 41 includes a substantially rectangular plate-like second bottom wall part 42 (an example of a flange) having the same dimensions as the first bottom wall part 32 of the first divided bobbin body 31, and a second bottom wall. The pair of second side walls 43 extending upward from the edges of the pair of sides extending in the front-rear direction of the portion 42 and the other pair of sides extending in the width direction (left-right direction) of the second bottom wall 42. A pair of support wall portions 45, 46 extending downward from the edges of the first and second support walls. In addition, a second hole portion 44 penetrating the plate surface is provided at the center portion of the second bottom wall portion 42, and a cylindrical portion 47 extending upward from the hole edge of the second hole portion 44 is provided. Yes.

  The height dimension of the pair of second side wall parts 43 is set to be equal to the projecting dimension of the side wall part 12 of the magnetic core 10 from the plate surface of the bottom wall part 11. The upper end surface is flush with the upper end surface of the side wall 12 of the magnetic core 10 (see FIGS. 2 to 4).

  The dimension between the pair of support wall portions 45 and 46 (inside) is set to be slightly larger than the length dimension of the bottom wall portion 11 of the magnetic core 10 in the front-rear direction. The bottom wall portion 11 of the magnetic core 10 is fitted between the support wall portions 45 and 46 (see FIGS. 2 and 3). That is, in the assembled state, the pair of support wall portions 45 and 46 protrude outward from the bottom wall portion 11 of the magnetic core 10. Further, the projecting dimension of the pair of support wall parts 45 and 46 from the plate surface of the second bottom wall part 42 is set to be equal to the height dimension (thickness dimension) of the bottom wall part 11 of the magnetic core 10. In the assembled state, the lower end surfaces of the support wall portions 45 and 46 are flush with the lower surface of the bottom wall portion 11 of the magnetic core 10 (see also FIGS. 2 to 4).

  Further, the second hole portion 44 is set to have a slightly larger diameter than the column portion 13 so as to penetrate the column portion 13 of the magnetic core 10 (second core 10B). In other words, the cylindrical portion 47 is set to have an inner diameter dimension through which the column portion 13 can be inserted. Further, the projecting dimension of the tubular part 47 from the second bottom wall part 42 is the same as the projecting dimension of the second side wall part 43 from the second bottom wall part 42 (see FIG. 7).

  The winding portion 21 of the coil 20 described above is fitted around the cylindrical portion 47. In other words, the inner diameter dimension of the winding part 21 is set to be slightly larger than the outer diameter dimension of the cylindrical part 47.

  Of the pair of support wall portions 45, 46 of the second divided bobbin body 41, a pair of fitting grooves 48 are cut out on the front surface of the front support wall portion 45 arranged on the front side so as to extend in the vertical direction. Is provided. The pair of fitting grooves 48 are provided at a width dimension and a position where the first stepped portion 24A and the second stepped portion 24B of the coil 20 described above can be fitted in the state where the coil assembly 1 is assembled. Thereby, the first end 22A and the second end 22B of the coil 20 are stably held.

  Further, of the pair of support wall portions 45, 46 of the second divided bobbin body 41, the lower surface of the rear support wall portion 46 (an example of the overhang portion) disposed on the rear side (an example of the opposing surface) A protruding portion 49 that protrudes toward the surface is provided. The projecting portion 49 is provided at a position that is deviated slightly toward the front side of the center portion in the width direction of the rear support wall portion 46 and in the front-rear thickness direction (see FIGS. 6 and 7).

(Circuit structure 53)
As shown in FIG. 9, the coil assembly 1 described above is placed at a predetermined position on a circuit board 50 (an example of a base member), and the pair of connection portions 25 </ b> A and 25 </ b> B are exposed from the opening 51. The bus bar 52 is electrically connected by soldering (circuit structure 53).

(Function and effect)
According to the coil assembly 1 of the present embodiment described above, the protrusion 49 is held at a position away from the circuit board 50 by contacting the circuit board 50, and the entire coil assembly 1 is directed forward. Tilt. Therefore, the first connection portion 25 </ b> A and the second connection portion 25 </ b> B of the coil 20 are pressed toward the bus bar 52. Thereby, even when the dimensional accuracy of the first end portion 22A and the second end portion 22B derived from the winding portion 21 of the coil 20 is not high, the first connection portion 25A and the second connection portion 25B are securely connected to the bus bar 52. Therefore, the electrical connection reliability between the two is improved.

  Moreover, since the coil assembly 1 includes the bobbin 30, the coil 20 and the magnetic core 10 can be relatively positioned by the bobbin 30. Further, since the protrusion 49 is provided on the rear support wall 46 of the bobbin 30, the number of parts can be reduced as compared with the case where the protrusion 49 is formed on a part different from the bobbin 30. it can.

  Further, a step is formed between the circuit board 50 and the bus bar 52 by the thickness dimension of the circuit board 50. According to the coil assembly 1 of the present embodiment, there is such a step. Even in this case, the electrical connection reliability between the connection portions 25A and 25B of the coil 20 and the bus bar 52 can be improved.

  Thus, according to the coil assembly 1 of the present embodiment, the connection reliability between the coil 20 and the bus bar 52 can be improved.

Second Embodiment
A second embodiment will be described with reference to FIGS.

  In the coil assembly 2 of this embodiment, a coil (not shown in its entirety) having a form substantially similar to that of the first embodiment is housed in a coil case 70 together with a magnetic core (not shown) and filled with a potting material. And fixed form.

  The coil case 70 is made of insulating resin, and has a box shape in which a coil winding portion can be accommodated and one side surface is opened by an opening 71 as shown in FIGS. 11 and 12. . At the four corners of the lower surface 70A (an example of the opposing surface) of the coil case 70, cylindrical positioning protrusions 72 (an example of the protrusions) that protrude downward are integrally provided. In addition, a pair of plate-like fixing pieces 73 are erected vertically on the pair of side walls sandwiching the opening 71 toward the outside. Each of the fixing pieces 73 is formed with a fixing hole 74 through which a fixing bolt for attaching to a coil base (not shown) passes.

  The coil is substantially the same as that of the above embodiment, except that the lower surface of the connecting portion 65 is set at a position where it is flush with the lower surface 70A of the coil case 70, and the connecting through hole 66 is provided in the connecting portion 65. The provided point is different from the coil 20 of the above embodiment (see FIG. 10).

  The coil assembly 2 of the present embodiment is accommodated in the coil case 70 in a direction in which the pair of terminal portions 62 of the coil described above protrudes outward from the opening 71, and the potting material is filled and solidified. can get.

  Such a coil assembly 2 of this embodiment is arranged on a base member. The base member in the present embodiment is a heat radiating plate 85, and a positioning recess 86 (an example of a recess) for fitting the positioning protrusion 72 of the coil assembly 2 is provided at a predetermined position of the heat radiating plate 85. . The positioning recess 86 is set to have an inner diameter slightly larger than the outer diameter of the positioning protrusion 72 of the coil case 70, and the adhesive 90 can be filled between the positioning protrusion 72. .

  A receiving recess 87 for fitting the nut 91 is provided at a predetermined position of the heat radiating plate 85. A connection portion of the bus bar 82 led out from the circuit board 80 fixed on the heat sink 85 is arranged on the nut 91 accommodated in the receiving recess 87, and the connection bolt 92 and the nut 91 are fastened. The coil connection portion 65 and the bus bar 82 (circuit board 80) are electrically connected.

  According to the circuit configuration body 83 of this embodiment, in the state where the coil assembly 2 is disposed on the heat sink 85, the coil assembly 2 has the positioning protrusion 72 in the positioning recess 86 of the heat sink 85. Since the displacement is suppressed by being fitted, the connection reliability between the circuit board 80 and the coil assembly 2 is improved.

  In addition, since the adhesive 90 is provided between the positioning projection 72 and the positioning recess 86, the displacement is more reliably suppressed, and the connection reliability between the circuit board 80 and the coil assembly 2 is further improved. To do.

  Further, since the positioning protrusion 72 is provided integrally with the coil case 70, the positioning protrusion 72 can be provided with a simple structure.

<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 first embodiment, the protruding portion 49 is integrally provided on the rear support wall portion 46 of the bobbin 30, but the protruding portion presses the connecting portion against the bus bar by incorporating another member into the coil assembly. It is good also as a structure which provides a part. Alternatively, the magnetic core 10 may be provided with a protruding portion.

  (2) The projecting portion is not limited to the projecting portion, and may be in any form such as a plate shape in which the coil assembly is tilted forward.

  (3) In the first embodiment, only one protrusion 49 is provided. However, a plurality of protrusions 49 may be provided.

  (4) The form of the magnetic core 10 and the bobbin 30 is not limited to the above embodiment. For example, as the magnetic core, other types of cores such as a PQ core, an EI core, an EER core, and an EPC core may be used in addition to the E type core.

  (5) In the first embodiment, the first connection portion 25A and the second connection portion 25B are arranged at the same height (on the same plane), and both are connected to the bus bar 52 on the back side through the opening 51 of the circuit board 50. Although it was set as a structure, it is good also as a structure connected to the bus-bar distribute | arranged to different height. For example, one connecting portion may be connected to the bus bar 52 disposed on the surface of the circuit board 50.

  (6) In the second embodiment, the example in which the terminal portion 62 of the coil is bent in a crank shape is shown, but the form of the terminal portion is not limited to the above embodiment. For example, as shown in FIG. 13, the terminal part 162 may be extended straight from the winding part. In such a case, for example, a terminal block 188 having a predetermined height is provided on the base member (heat radiating plate 185), and the bus bar 182 extended from the circuit board is placed on the terminal block 188, and the terminal block 162 is shared. By fastening, the circuit structure 183 in which the coil assembly 3 and the circuit board are connected can be obtained.

  (7) Although the coil case 70 is made of an insulating resin in the second embodiment, it may be a metal coil case. In this case, an insulating sheet or the like may be provided between the radiator plate 85 and the like.

  (8) In the second embodiment, the coil assembly 2 is arranged on the heat radiating plate 85, but may be arranged on the circuit board 80. In this case, a hole for allowing the positioning protrusion 72 to pass through the circuit board 80 can be provided, and the hole can be positioned by being fitted into the positioning recess 86 of the heat radiating plate 85 disposed on the lower surface side of the circuit board 80.

  (9) The heat dissipation plate 85 is not necessarily required, and the base member may be only a circuit board.

1, 2, 3 ... Coil assembly 10 ... Magnetic core 10A ... First core 10B ... Second core 11 ... Bottom wall (wall)
DESCRIPTION OF SYMBOLS 12 ... Side wall part 13 ... Column part 20 ... Coil 21 ... Winding part 22A ... 1st edge part (terminal part)
22B ... Second end (terminal part)
23A ... 1st extension part 23B ... 2nd extension part 24A ... 1st level | step-difference part 24B ... 2nd level | step-difference part 25A ... 1st connection part 25B ... 2nd connection part 30 ... Bobbin 31 ... 1st division | segmentation bobbin body 32 ... 1st bottom wall (buttock)
41 ... 2nd divided bobbin body 42 ... 2nd bottom wall part (saddle part)
45 ... Front support wall 46 ... Back support wall (overhang)
47 ... cylindrical part 48 ... fitting groove 49 ... projecting part 50, 80 ... circuit board 51 ... opening parts 52, 82, 182 ... bus bars 53, 83, 183 ... circuit structure 62 ... terminal part 66 ... connection part 70 ... Coil case 72 ... Positioning protrusion (protruding part)
85 ... Heat sink (base member)

Claims (8)

A coil assembly disposed on a base member,
A coil comprising a flat wire, and having a winding portion in which the flat wire is wound edgewise, and a pair of terminal portions extending from the winding portion,
The terminal portion extends from a surface intersecting the base member;
A coil assembly, wherein a projecting portion projecting toward the base member is provided on a facing surface facing the base member. Mounted on a circuit board included in the base member,
The terminal portion includes an extending portion extending in an extending direction from the winding portion, a step portion bent in an intersecting direction intersecting the extending direction from the extending portion, and the step portion from the step portion. A connecting portion bent in the extending direction,
The projecting portion is provided at a position opposite to the connecting portion and the extending direction, and contacts the circuit board, and the portion of the coil opposite to the connecting portion and the extending direction is connected to the circuit. The coil assembly of claim 1, wherein the coil assembly is spaced from the substrate. A magnetic core and a bobbin that contacts both the coil and the magnetic core to hold the relative position of the coil and the magnetic core;
The coil assembly according to claim 2, wherein the protrusion is provided on the bobbin. The magnetic core includes a pair of wall portions that sandwich the coil from the axial direction of the winding portion, and a pillar portion that extends from the wall portion in the axial direction and is inserted inside the winding portion. ,
The bobbin is disposed between the winding portion and the wall portion, and a tubular portion disposed between the winding portion and the column portion, and projecting outward from both ends of the tubular portion. And a pair of collars
The flange portion includes an overhanging portion that projects outward from the wall portion of the magnetic core on the opposite side of the extending direction,
The coil assembly according to claim 3, wherein the protruding portion is provided on the projecting portion. A circuit assembly in which the coil assembly according to any one of claims 2 to 4 is mounted on a circuit board,
The circuit board has a bus bar laminated on a surface opposite to a surface on which the coil assembly is mounted,
The circuit board has an opening through which the bus bar is exposed;
The connection part is a circuit structure connected to the bus bar exposed from the opening. The coil assembly according to claim 1, wherein the coil is fixed in a coil case, and the protrusion is provided on the coil case. A circuit structure comprising the coil assembly according to claim 1 or 6,
The base member is a circuit structure having a recess for fitting the protruding portion. The circuit structure according to claim 7, wherein an adhesive is provided between the protruding portion and the concave portion.

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