Coil device

Abstract

To provide a coil device which can prevent a short-circuiting failure caused at the time of mounting.SOLUTION: A coil device 1 has: a core having a mounting surface 15; a first conductor 30 made of a wire; and a second conductor 40 made of a conductor plate. The first conductor 30 has a first body part 31 which extends along the mounting surface 15 inside the core. The second conductor 40 has a second body part 41 which extends along the mounting surface 15 inside the core and faces the first body part 31. In a direction where the first body part 31 faces the second body part 41, the first body part 31 is located on one side of the core, and the first body part 31 and the second body part 41 are offset toward the one side of the core where the first body part 31 is located.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a coil device that can be used, for example, as a coupled inductor. [Background technology]

[0002] For example, in the power supply circuit of a server, a coil device called a coupled inductor may be used to improve the response speed of a voltage regulator or to reduce the number of components in the power supply circuit. As an example of this type of coil device, Patent Document 1 discloses a coil device having a core, a first conductor, and a second conductor. The first conductor and the second conductor are composed of conductive plates formed by bending a copper plate into a predetermined shape. The first conductor and the second conductor face each other at a predetermined distance inside the core and are magnetically coupled.

[0003] In recent years, with the progress of miniaturization of coil devices, the distance between the conductors tends to become narrower. For example, in the coil device of Patent Document 1, if an attempt is made to further miniaturize the device, the first conductor and the second conductor are brought closer to each other, and the distance between the first conductor and the second conductor becomes narrower. Therefore, when the coil device is mounted on a mounting board, solder or the like may be attached so as to straddle the first conductor and the second conductor, which may cause a short circuit between the first conductor and the second conductor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-117676 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a coil device capable of preventing short circuit defects during mounting. [Means for solving the problem]

[0006] In order to achieve the above object, the coil device of the present disclosure is: a core having a mounting surface; A first conductor formed of a wire; A second conductor formed of a conductor plate, the first conductor has a first body portion extending along the mounting surface inside the core, the second conductor extends along the mounting surface inside the core and has a second body portion facing the first body portion; In the direction in which the first body portion and the second body portion oppose each other, the first body portion is located on one side of the core, and the first body portion and the second body portion are offset to the one side of the core where the first body portion is located.

[0007] In the coil device of the present disclosure, the first conductor is made of a wire, and the second conductor is made of a conductive plate. Therefore, for the first conductor, punching or bending of the conductive plate is not required. This makes it possible to easily manufacture the coil device and reduce costs.

[0008] In addition, in the direction in which the first body portion and the second body portion face each other, the first body portion and the second body portion are offset to one side of the core where the first body portion is located. Therefore, a space is formed on the other side of the core according to the offset amount of the first body portion and the second body portion. By utilizing this space and arranging a part of the second conductor (for example, a mounting portion) so as to be separated from the first conductor, it is possible to prevent the occurrence of a short circuit defect between the first conductor and the second conductor.

[0009] Moreover, on the other side of the core, the volume of the core increases according to the offset amount between the first body portion and the second body portion, thereby improving the inductance characteristics and / or the DC bias characteristics of the coil device.

[0010] In the direction in which the first body portion and the second body portion face each other, the first body portion and the second body portion may be located on one side of the core from the center of the core. In this case, a space for arranging a part of the second conductor (e.g., a mounting portion) is formed at least on the other side of the core from the center of the core. By arranging a part of the second conductor (e.g., the mounting portion) in this space so as to be separated from the first conductor, it is possible to effectively prevent the occurrence of a short circuit defect between the first conductor and the second conductor.

[0011] The first conductor has a first mounting portion exposed from the core, and the second conductor has a second mounting portion exposed from the core, and the second mounting portion extends to the other side of the core so as to be spaced apart from the first mounting portion. In this case, the second mounting portion is disposed at a position spaced apart from the first mounting portion. Therefore, when the coil device is mounted on a mounting board, solder or the like is less likely to adhere across the first mounting portion and the second mounting portion. This makes it possible to effectively prevent short circuit defects from occurring between the first conductor and the second conductor.

[0012] The first mounting portion and the second mounting portion may be disposed inside the outer edge of the core when viewed from a direction perpendicular to the mounting surface. Such a configuration can be obtained, for example, by miniaturizing the first mounting portion and the second mounting portion or by increasing the volume of the core. In the former case, the coil device can be miniaturized. In the latter case, the inductance characteristics of the coil device can be improved.

[0013] The core has a recess formed on a side surface of the core perpendicular to the mounting surface, and the first mounting portion and the second mounting portion are housed in the recess. In this case, the first mounting portion and the second mounting portion are unlikely to be exposed from the outer edge of the core when viewed from the direction perpendicular to the mounting surface. This makes it possible to reduce the size of the coil device.

[0014] In a direction in which the first body portion and the second body portion face each other, a first width of the first body portion may be different from a second width of the second body portion. In this case, the magnetic coupling between the first body portion and the second body portion can be adjusted according to the difference between the first width and the second width. Also, a large current can be passed through the conductor having the larger of the first width and the second width.

[0015] The first width may be greater than the second width, allowing a large current to flow through the first conductor.

[0016] The height position of the first body part from the mounting surface may be different from the height position of the second body part from the mounting surface. In this case, the magnetic coupling between the first body part and the second body part can be adjusted according to the difference between the height position of the first body part from the mounting surface and the height position of the second body part from the mounting surface.

[0017] The first body portion may be in contact with the second body portion, thereby enhancing magnetic coupling between the first body portion and the second body portion.

[0018] The second conductor may have a plating layer formed on at least a part of the second conductor. For example, by forming a plating layer on an end (mounting portion) of the second conductor in an extending direction, the second conductor can be easily connected to a mounting board by solder or the like.

[0019] The first conductor may have an insulating coating layer formed on at least a part of the first conductor. In this case, the insulating coating layer can insulate the first conductor from the second conductor. Therefore, a short circuit between the first conductor and the second conductor can be effectively prevented. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a coil device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a perspective view of the first core shown in FIG. [Diagram 3]FIG. 3 is an exploded perspective view of the coil device shown in FIG. [Figure 4] FIG. 4 is a perspective view of the first conductor and the second conductor shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV of the coil device shown in FIG. [Figure 6] FIG. 6 is a plan view of the first core to which the first conductor and the second conductor shown in FIG. 3 are attached. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that the contents shown in the drawings are merely shown in a schematic and illustrative manner for understanding the present disclosure, and the appearance and dimensional ratios may differ from the actual product. In addition, the present disclosure is not limited to the following embodiments.

[0022] 1 functions as a coupled inductor and is provided, for example, in a power supply circuit of a server. The coil device 1 has a first core 10, a second core 20, a first conductor 30, and a second conductor 40. In this embodiment, the coil device 1 is configured with two cores, the first core 10 and the second core 20, but may be configured with one core or three or more cores.

[0023] In FIG. 1 to FIG. 6, the X-axis is an axis along the axial direction of the first conductor 30 (first main body portion 31) or the second conductor 40 (second main body portion 41). The Y-axis is an axis along the direction in which the first conductor 30 and the second conductor 40 face each other. The Z-axis is an axis perpendicular to the X-axis and the Y-axis. The X-axis, the Y-axis, and the Z-axis are perpendicular to each other. In the following, for each of the X-axis, the Y-axis, and the Z-axis, the direction away from the center of the coil device 1 is referred to as the "outside" and the direction approaching the center of the coil device 1 is referred to as the "inside". In addition, the positive side of the Z-axis is referred to as the "upper side", and the negative side of the Z-axis is referred to as the "lower side". However, the upper side in the Z-axis direction does not necessarily coincide with the upper side in the vertical direction. In addition, the lower side in the Z-axis direction does not necessarily coincide with the lower side in the vertical direction.

[0024] The width of the coil device 1 in the X-axis direction is not particularly limited, but is, for example, 3.0 to 20.0 mm. The width of the coil device 1 in the Y-axis direction is not particularly limited, but is, for example, 3.0 to 10.0 mm. The thickness of the coil device 1 in the Z-axis direction is not particularly limited, but is, for example, 3.0 to 10.0 mm.

[0025] As shown in FIG. 2, the first core 10 has a first side surface 11, a second side surface 12, a third side surface 13, a fourth side surface 14, a mounting surface 15, and a mounting-facing surface 16. The first side surface 11 and the second side surface 12 have the same shape and are located on opposite sides along the Y axis. The first side surface 11 and the second side surface 12 are rectangular in shape, but may be square or other polygonal. The third side surface 13 and the fourth side surface 14 have the same shape and are located on opposite sides along the X axis. The mounting surface 15 and the mounting-facing surface 16 are located on opposite sides along the Z axis. The first core 10 has a flat shape in which the width in the Z axis direction is smaller than the width in the X axis direction and the width in the Y axis direction.

[0026] The first core 10 has a groove 17 formed in the mounting surface 16. The groove 17 is located on one side in the Y-axis direction of the first core 10 (the second side surface 12 side) and extends along the X-axis. The groove 17 has a bottom surface 170 and inner walls 171 and 172. The bottom surface 170 is a flat surface parallel to the mounting surface 15. The inner walls 171 and 172 are surfaces perpendicular to the bottom surface 170. The inner walls 171 and 172 face each other along the Y-axis.

[0027] In this embodiment, "parallel" is not limited to strictly parallel, and "perpendicular" is not limited to strictly perpendicular.

[0028] The first core 10 has a recess 18a formed on the third side surface 13 and a recess 18b formed on the fourth side surface 14. Both the third side surface 13 and the fourth side surface 14 are perpendicular to the mounting surface 15. The recess 18a is recessed inward from the third side surface 13 along the X-axis. The recess 18b is recessed inward from the fourth side surface 14 along the X-axis. The recesses 18a and 18b have a side bottom surface 180. The side bottom surface 180 is a flat surface and perpendicular to the mounting surface 15. The groove portion 17 extends along the X-axis from the side bottom surface 180 of the recess 18a to the side bottom surface 180 of the recess 18b.

[0029] The first core 10 is formed of a composite material containing a magnetic material and a resin. The first core 10 is formed, for example, by powder compaction, injection molding, or cutting. The magnetic material constituting the first core 10 is not particularly limited, but may be, for example, ferrite (Ni-Zn ferrite, Mn-Zn ferrite, etc.) or a metallic magnetic body. The resin constituting the first core 10 is not particularly limited, but may be, for example, an epoxy resin or a phenol resin.

[0030] As shown in Fig. 3, the second core 20 has a rectangular parallelepiped shape. The second core 20 has a flat shape in which the width in the Z-axis direction is smaller than the width in the X-axis direction and the width in the Y-axis direction. The second core 20 is formed by, for example, powder molding, injection molding, or cutting. The second core 20 has an abutment surface 21 that abuts against the mounting surface 16 of the first core 10. The second core 20 (abutment surface 21) is adhered to the first core 10 (mounting surface 16) by, for example, an adhesive.

[0031] The material constituting the second core 20 may be the same as or different from the material constituting the first core 10. The relative permeability of the second core 20 may be the same as or different from the relative permeability of the first core 10.

[0032] The width of the second core 20 in the X-axis direction is, but is not particularly limited to, equal to the maximum width of the first core 10 in the X-axis direction. The width of the second core 20 in the Y-axis direction is, but is not particularly limited to, equal to the width of the first core 10 in the Y-axis direction. The thickness of the second core 20 in the Z-axis direction is, but is not particularly limited to, thinner than the thickness of the first core 10 in the Z-axis direction.

[0033] The first conductor 30 shown in FIG. 4 is made of a wire (rectangular wire in this embodiment). The first conductor 30 has flexibility (lower rigidity than the second conductor 40) and is configured to be freely deformed (flexible). The first conductor 30 is formed by bending a wire into a shape (C-shape) shown in FIG. 4. The first conductor 30 is an insulating coated wire in which a conductive core wire such as a rectangular wire is coated with an insulating coating (insulating coating layer) 33. More specifically, the first conductor 30 is a known winding wire such as AIW (polyamideimide copper wire), UEW (polyurethane copper wire), PEW (polyester copper wire), etc. The material constituting the first conductor 30 is not particularly limited, and may be, for example, copper, copper alloy, silver, or nickel. The first conductor 30 may not have the coating 33.

[0034] The first conductor 30 is a primary coil, and the second conductor 40 is a secondary coil. However, the first conductor 30 may be a secondary coil, and the second conductor 40 may be a primary coil. The first conductor 30 and the second conductor 40 form a coupled coil that is magnetically coupled to each other.

[0035] As shown in Fig. 4, the first conductor 30 has a first main body portion 31 and first mounting portions 32a and 32b. The first main body portion 31 is elongated and extends linearly along the X-axis. The cross-sectional shape of the first main body portion 31 is rectangular, but may be a square, trapezoid, other polygonal shape, or other shape. The first width W1 in the Y-axis direction of the first conductor 30 is not particularly limited, but is 0.1 to 2.0 mm.

[0036] The first main body portion 31 has a top surface, a bottom surface, and two side surfaces. These surfaces are flat surfaces perpendicular to each other. The top surface and the bottom surface are located on opposite sides along the Z axis and are parallel to each other. The two side surfaces are located on opposite sides along the Y axis and are parallel to each other. The top surface and the bottom surface are parallel to the XY plane (mounting surface 15 in FIG. 3), and the two side surfaces are perpendicular to the XY plane (mounting surface 15 in FIG. 3).

[0037] At least one of the two side surfaces, the top surface, and the bottom surface of the first main body portion 31 does not have to be a flat surface, and may be, for example, an inclined surface, an uneven surface, a curved surface, or a bent surface. For example, the side surface of the first main body portion 31 is perpendicular to the XY plane (i.e., the mounting surface 15 in FIG. 3), but may be an inclined surface that is inclined at a predetermined angle (for example, 30° or more and less than 90°) with respect to the mounting surface 15.

[0038] The first mounting portion 32a is continuous with one axial end of the first main body portion 31, and the first mounting portion 32b is continuous with the other axial end of the first main body portion 31. In Fig. 4, the boundary between the first main body portion 31 and the first mounting portion 32a and the boundary between the first main body portion 31 and the first mounting portion 32b are indicated by dashed dotted lines. The shape of the first mounting portion 32a is the same as the shape of the first mounting portion 32b, but may be different.

[0039] The first mounting portions 32a and 32b are bent in an L-shape. The first mounting portions 32a and 32b are connected to a mounting board by solder, conductive adhesive, etc. The first mounting portions 32a and 32b each have a curved portion 321 and a leg portion 322.

[0040] The curved portion 321 is continuous with the first main body portion 31, and is curved in an L-shape (C-shape) between the first main body portion 31 and the leg portion 322. The leg portion 322 extends linearly along the Z-axis. The leg portion 322 is perpendicular to the first main body portion 31. The cross-sectional shape of the leg portion 322 is rectangular, but may be a square, another polygon, or another shape.

[0041] The coating 33 covers the first main body portion 31, the curved portion 321, and a part of the leg portion 322. The coating 33 is peeled off from a part of the leg portion 322 so that solder, a conductive adhesive, or the like can be easily attached. However, the coating 33 may cover the entire leg portion 322. The coating 33 covers the entire first main body portion 31, but may also cover only a part of the first main body portion 31.

[0042] The second conductor 40 has a second body portion 41 and second mounting portions 42a and 42b. The second body portion 41 is elongated and extends linearly along the X-axis. The second body portion 41 is disposed in parallel with the first body portion 31. The cross-sectional shape of the second body portion 41 is rectangular, but may be a square, a trapezoid, another polygon, or another shape. The second width W2 of the second conductor 40 in the Y-axis direction is not particularly limited, but is 0.1 to 2.0 mm.

[0043] The second conductor 40 is formed by a metal frame. The second conductor 40 is formed, for example, by machining (for example, punching, bending, cutting, pressing, sheet metal processing, casting, or forging) a metal plate (conductor plate) or a metal piece (conductor piece) into the shape shown in FIG. 4. The second conductor 40 has higher rigidity than general wires (round wire, rectangular wire, etc.). The rigidity of the second conductor 40 is higher than the rigidity of the first conductor 30. The material constituting the second conductor 40 is not particularly limited, but is, for example, copper, copper alloy, silver, or nickel.

[0044] A plating film (plating layer) is formed on at least a part of the second conductor 40. In this embodiment, the plating film is formed on the entire second conductor 40, but the plating film may be formed only on a part of the second conductor 40 (for example, the second mounting parts 42a and 42b). By forming the plating layer on the second mounting parts 42a and 42b, the solder wettability of the second mounting parts 42a and 42b is improved. Therefore, it becomes easier to connect the second conductor 40 to the mounting board by solder, conductive adhesive, etc. The plating film may be a single layer or multiple layers. The plating film is not particularly limited, but may be, for example, Cu plating, Ni plating, Sn plating, Ni-Sn plating, Cu-Ni-Sn plating, Ni-Au plating, or Au plating.

[0045] The second main body portion 41 has a top surface, a bottom surface, and two side surfaces. These surfaces are flat surfaces perpendicular to each other. The top surface and the bottom surface are located on opposite sides along the Z axis and are parallel to each other. The two side surfaces are located on opposite sides along the Y axis and are parallel to each other. The top surface and the bottom surface are parallel to the XY plane (mounting surface 15 in FIG. 3), and the two side surfaces are perpendicular to the XY plane (mounting surface 15 in FIG. 3).

[0046] At least one of the two side surfaces, the top surface, and the bottom surface of the second main body portion 41 does not have to be a flat surface, and may be, for example, an inclined surface, an uneven surface, a curved surface, or a bent surface. For example, the side surface of the second main body portion 41 is perpendicular to the XY plane (i.e., the mounting surface 15 in FIG. 3), but may be an inclined surface that is inclined at a predetermined angle (for example, 30° or more and less than 90°) with respect to the mounting surface 15.

[0047] In the direction in which the first body portion 41 and the second body portion 42 face each other (the Y-axis direction), the first width W1 of the first body portion 31 is different from the second width W2 of the second body portion 41. Therefore, it is possible to adjust the magnetic coupling between the first body portion 31 and the second body portion 41 according to the difference between the first width W1 and the second width W2. Also, it is possible to pass a large current through the conductor having the larger of the first width W1 and the second width W2 (the first conductor 30 in this embodiment).

[0048] The first width W1 is larger than the second width W2. The ratio W1 / W2 of the first width W1 to the second width W2 is not particularly limited, but 1 < W1 / W2 ≤ 4, or 1 < W1 / W2 ≤ 2, or 2 ≤ W1 / W2 ≤ 3. In this case, the inductance characteristics and / or the DC superposition characteristics of the coil device 1 are improved.

[0049] The second mounting portion 42a is continuous with one axial end of the second main body portion 41, and the second mounting portion 42b is continuous with the other axial end of the second main body portion 41. In FIG. 4, the boundary between the second main body portion 41 and the second mounting portion 42a and the boundary between the second main body portion 41 and the second mounting portion 42b are indicated by a dashed-dotted line. The shape of the second mounting portion 42a may be the same as or different from the shape of the second mounting portion 42b.

[0050] The second mounting portions 42a and 42b have a bent shape. The second mounting portions 42a and 42b are connected to the mounting substrate by solder, a conductive adhesive, or the like. The second mounting portions 42a and 42b each have a curved portion 421, a leg portion 422, and an intermediate portion 423.

[0051] The curved portion 421 is continuous with the second main body portion 41 and is curved in an L shape (C shape) between the second main body portion 41 and the intermediate portion 423. The intermediate portion 423 is located between the curved portion 421 and the leg portion 422. The intermediate portion 423 is orthogonal to the curved portion 421 and the leg portion 422. The intermediate portion 423 extends linearly along the Y axis so as to be separated from the leg portion 322 of the first conductor 30. The leg portion 422 extends linearly along the Z axis. The cross-sectional shape of the leg portion 422 is rectangular, but it may be square, another polygon, or another shape.

[0052] As shown in FIG. 3, the first body portion 31 and the second body portion 41 are disposed inside the groove portion 17. The first body portion 31 extends along the mounting surface 15 inside the groove portion 17. The second body portion 41 extends along the mounting surface 15 inside the groove portion 17 in parallel with the first body portion 31. The depth of the groove portion 17 is equal to or greater than the thickness in the Z-axis direction of the first body portion 31 or the second body portion 41 so that the first body portion 31 and the second body portion 41 are not exposed from the groove portion 17. As shown in FIG. 5, the first body portion 31 is bonded to the bottom surface 170 of the groove portion 17 by the adhesive 70. In addition, the second body portion 41 is bonded to the bottom surface 170 by the adhesive 70. However, the upper surface of the first body portion 31 may be bonded to the abutting surface 21 of the second core 20 by the adhesive 70. In addition, the upper surface of the second main body portion 41 may be adhered to the contact surface 21 of the second core 20 by an adhesive 70.

[0053] The first body portion 31 and the second body portion 41 face each other along the Y-axis. In addition, the side surface of the first body portion 31 (the side surface facing the second body portion 41) is in contact with the side surface of the second body portion 41 (the side surface facing the first body portion 31). This can enhance the magnetic coupling between the first body portion 31 and the second body portion 41. Since the first body portion 31 has a coating (insulating coating layer) 33, the first body portion 31 can be insulated from the second body portion 41 by the coating 33. This can prevent a short circuit failure between the first body portion 31 and the second body portion 41.

[0054] A gap may be formed between the first body portion 31 and the second body portion 41. In this case, the magnetic coupling between the first body portion 31 and the second body portion 41 can be adjusted according to the size of the gap. The gap may be an air gap. Alternatively, the inside of the gap may be filled with adhesive (for example, adhesive containing beads). Alternatively, a part of the first core 10 or the second core 20 may be disposed in the gap. Alternatively, a partition member (spacer) or a film formed of a non-conductive member such as a resin may be disposed in the gap.

[0055] A gap 61 is formed between the first body portion 31 and the inner wall 171 of the groove portion 17, but the first body portion 31 may abut against the inner wall 171. Alternatively, the first body portion 31 and the inner wall 171 may be bonded together by an adhesive.

[0056] Furthermore, a gap 62 is formed between the second body portion 41 and the inner wall 172 of the groove portion 17, but the second body portion 41 may be in contact with the inner wall 172. Alternatively, the second body portion 41 and the inner wall 172 may be bonded together with an adhesive.

[0057] The first body portion 31 and the second body portion 41 are housed in a space defined by the groove portion 17 so as to be sandwiched from above and below by the first core 10 and the second core 20. The upper surface of the first body portion 31 and the abutment surface 21 of the second core 20 are in contact with each other, but a gap may be formed therebetween. Also, the upper surface of the second body portion 41 and the abutment surface 21 of the second core 20 are in contact with each other, but a gap may be formed therebetween.

[0058] The height position of the first body portion 31 (including the coating 33) from the mounting surface 15 is equal to the height position of the second body portion 41 from the mounting surface 15. Therefore, the top surface of the first body portion 31 (including the coating 33) is flush with the top surface of the second body portion 41, and the bottom surface of the first body portion 31 is flush with the bottom surface of the second body portion 41.

[0059] However, the height position of the first body portion 31 from the mounting surface 15 may be different from the height position of the second body portion 41 from the mounting surface 15. The height position of the first body portion 31 from the mounting surface 15 may be higher than the height position of the second body portion 41 from the mounting surface 15. Alternatively, the height position of the second body portion 41 from the mounting surface 15 may be higher than the height position of the first body portion 31 from the mounting surface 15. In either case, the magnetic coupling between the first body portion 31 and the second body portion 41 can be adjusted depending on the difference between the height position of the first body portion 31 from the mounting surface 15 and the height position of the second body portion 41 from the mounting surface 15.

[0060] When viewed from the X-axis direction, the leg 322 of the first mounting portion 32b is located more inward in the Y-axis direction than the second side surface 12 of the first core 10. Although detailed illustration is omitted, the same applies to the leg 322 of the first mounting portion 32a. Furthermore, when viewed from the X-axis direction, the leg 422 of the second mounting portion 42b is located more inward in the Y-axis direction than the first side surface 11 of the first core 10. Although detailed illustration is omitted, the same applies to the leg 422 of the second mounting portion 42a.

[0061] The lower part of leg 322 protrudes downward from mounting surface 15 of first core 10. In addition, the lower part of leg 422 protrudes downward from mounting surface 15 of first core 10. Therefore, mounting surface 15 is located above the bottom surfaces of legs 322 and 422.

[0062] As shown in Fig. 1, the first mounting portions 32a and 32b are exposed from the first core 10 and the second core 20. Furthermore, the second mounting portions 42a and 42b are exposed from the first core 10 and the second core 20. More specifically, the curved portion 321 and the leg portion 322 shown in Fig. 4 are exposed from the first core 10 and the second core 20 at the recessed portion 18a or 18b shown in Fig. 1. Furthermore, the curved portion 421, the leg portion 422, and the middle portion 423 shown in Fig. 4 are exposed from the first core 10 and the second core 20 at the recessed portion 18a or 18b shown in Fig. 1.

[0063] The second mounting portion 42a (middle portion 423) extends toward the first side surface 11 of the first core 10 so as to be separated from the first mounting portion 32a. Although detailed illustration is omitted, the second mounting portion 42b (middle portion 423) extends toward the first side surface 11 of the first core 10 so as to be separated from the first mounting portion 32b. Therefore, the second mounting portion 42a is disposed at a position separated from the first mounting portion 32a in the Y-axis direction. As a result, when the coil device 1 is mounted on a mounting board, solder, conductive adhesive, etc. are less likely to adhere across the first mounting portion 32a and the second mounting portion 42a. This makes it possible to prevent a short circuit failure from occurring between the first conductor 30 and the second conductor 40.

[0064] The first mounting portions 32a and 32b are disposed on both sides in the X-axis direction of the first core 10 so as to sandwich the first core 10 from both sides in the X-axis direction. Also, as shown in Fig. 6, the second mounting portions 42a and 42b are disposed on both sides in the X-axis direction of the first core 10 so as to sandwich the first core 10 from both sides in the X-axis direction.

[0065] The first mounting portion 32a and the second mounting portion 42a are disposed inside the outer edge of the second core 20 when viewed from a direction perpendicular to the mounting surface 15 (Z-axis direction). The first mounting portion 32b and the second mounting portion 42b are disposed inside the outer edge of the second core 20 when viewed from a direction perpendicular to the mounting surface 15 (Z-axis direction). The first mounting portion 32a and the second mounting portion 42a are miniaturized so that the first mounting portion 32a and the second mounting portion 42a are not exposed to the outside from the outer edge of the second core 20, thereby making it possible to miniaturize the coil device 1. The inductance characteristics of the coil device 1 can be improved by increasing the volume of the second core 20 so that the first mounting portion 32a and the second mounting portion 42a are not exposed to the outside from the outer edge of the second core 20.

[0066] The first mounting portions 32a and 32b are covered from above by the second core 20 shown by the two-dot chain line in Fig. 6. Therefore, when viewed from above, the first mounting portions 32a and 32b are hidden by the second core 20. In addition, the second mounting portions 42a and 42b are covered from above by the second core 20 shown by the two-dot chain line in Fig. 6. Therefore, when viewed from above, the second mounting portions 42a and 42b are hidden by the second core 20.

[0067] The first mounting portion 32a and the second mounting portion 42a are housed in the recess 18a. The first mounting portion 32b and the second mounting portion 42b are housed in the recess 18b. Therefore, the first mounting portion 32a, the first mounting portion 32b, the second mounting portion 42a, and the second mounting portion 42b are less likely to be exposed from the outer edge of the second core 20, and the coil device 1 can be made more compact.

[0068] As shown in FIG. 6, in the direction in which the first body portion 31 and the second body portion 41 face each other (Y-axis direction), the first body portion 31 and the second body portion 41 are integrally offset to one side (the second side surface 12 side) of the first core 10 where the first body portion 31 is located. The direction in which the first body portion 31 and the second body portion 41 are offset is the side on which the first body portion 31 is located, in other words, the opposite side to the side on which the second body portion 41 is located. In this embodiment, both the first body portion 31 and the second body portion 41 are offset to one side of the first core 10. In addition, both the first body portion 31 and the second body portion 41 are offset to one side of the second core 20 (the negative Y-axis direction side). In addition, the first mounting portions 32a and 32b are offset to one side of the first core 10 and the second core 20.

[0069] In a direction in which the first body portion 31 and the second body portion 41 face each other (Y-axis direction), the first body portion 31 and the second body portion 41 are located on one side of the first core 10 (the second side surface 12 side) of the center C1 of the first core 10. In this embodiment, the entire first body portion 31 is located on one side of the first core 10 from the center C1 of the first core 10 in the Y-axis direction. Also, the entire second body portion 41 is located on one side of the first core 10 from the center C1 of the first core 10 in the Y-axis direction. However, a part of the second body portion 41 may be located on the other side of the first core 10 (the first side surface 11 side) from the center C1 of the first core 10 in the Y-axis direction.

[0070] The position of the center C1 of the first core 10 is equal to the position of the center of the second core 20. Here, "equal" does not only mean that these positions exactly match, but also includes a state in which these positions are shifted by a few percent (e.g., 5%) or less in the Y-axis and / or X-axis directions.

[0071] The first body portion 31 and the second body portion 41 are magnetically coupled to each other to form a magnetic coupling portion 50. The magnetic coupling portion 50 is a virtual structure in which the first body portion 31 and the second body portion 41 are regarded as a single configuration. The magnetic coupling between the first body portion 31 and the second body portion 41 can be adjusted according to the distance between the first body portion 31 and the second body portion 41 along the Y axis.

[0072] The central axis C2 of the magnetic coupling unit 50 is spaced a distance D in the Y-axis direction from the center C1 of the first core 10. The ratio D / W3 of the distance D between the central axis C2 of the magnetic coupling unit 50 and the center C1 of the first core 10 to the width W3 in the Y-axis direction of the first core 10 or the second core 20 is not particularly limited, but is 1 / 10≦D / W3≦1 / 3 or 1 / 8≦D / W3≦1 / 4.

[0073] As described above, in the coil device 1 of this embodiment, the first conductor 30 is made of a wire, and the second conductor 40 is made of a conductive plate. Therefore, for the first conductor 30, there is no need to perform processes such as punching or bending a conductive plate. This makes it possible to facilitate the manufacture of the coil device 1 and reduce costs.

[0074] In addition, in the direction in which the first body portion 31 and the second body portion 41 face each other (Y-axis direction), the first body portion 31 and the second body portion 41 (magnetic coupling portion 50) are offset toward the second side surface 12 of the first core 10. Therefore, a space is formed on the first side surface 11 of the first core 10 according to the offset amount of the first body portion 31 and the second body portion 41. By utilizing this space, a part of the second conductor 40 (in this embodiment, the second mounting portions 42a and 42b) is disposed so as to be separated from the first conductor 30. This makes it possible to prevent the occurrence of a short circuit failure between the first conductor 30 and the second conductor 40 (particularly, the second mounting portions 42a and 42b).

[0075] Furthermore, on the first side surface 11 side of the first core 10, the volume of the first core 10 increases according to the offset amount of the first body portion 31 and the second body portion 41 (magnetic coupling portion 50). As a result, the inductance characteristics and / or the DC superposition characteristics of the coil device 1 are improved.

[0076] In addition, in the direction in which the first body portion 31 and the second body portion 41 face each other (Y-axis direction), the first body portion 31 and the second body portion 41 (magnetic coupling portion 50) are located closer to the second side surface 12 of the first core 10 than the center C1 of the first core 10. Therefore, a space for arranging a part of the second conductor 40 (in this embodiment, the second mounting portions 42a and 42b) is formed on the first side surface 11 side of the center C1 of the first core 10. In this space, a part of the second conductor 40 (in this embodiment, the second mounting portions 42a and 42b) is arranged so as to be spaced apart from the first conductor 30. This makes it possible to effectively prevent the occurrence of a short circuit failure between the first conductor 10 and the second conductor 40 (particularly, the second mounting portions 42a and 42b).

[0077] 4, the second width W2 in the Y-axis direction of the second body portion 41 is narrower than the first width W1 in the Y-axis direction of the first body portion 31. Therefore, compared to the case where the first width W1 and the second width W2 are equal, more arrangement space for the first core 10 (space corresponding to the difference between the first width W1 and the second width W2) is formed around the second body portion 41 shown in FIG. 6. As a result, the volume of the first core 10 increases around the second body portion 41, and the inductance characteristics and / or DC superposition characteristics of the coil device 1 are improved.

[0078] Next, a manufacturing method of the coil device 1 will be described. First, the first core 10, the second core 20, the first conductor 30, and the second conductor 40 shown in FIG. 3 are prepared. Next, the bottom surface of the first body portion 31 shown in FIG. 3 is adhered to the bottom surface 170 of the groove portion 17 shown in FIG. 2 by an adhesive, and the bottom surface of the second body portion 41 is adhered to the bottom surface 170. At this time, as shown in FIG. 6, the first body portion 31 and the second body portion 41 are closely attached so that they are in contact with each other. In addition, the first mounting portions 32a and 32b are disposed inside the recess 18a, and the second mounting portions 42a and 42b are disposed inside the recess 18b. Next, the abutment surface 21 of the second core 20 shown in FIG. 3 is adhered to the mounting facing surface 16 of the first core 10 by an adhesive. In this manner, the coil device 1 shown in FIG. 1 can be manufactured.

[0079] It should be noted that the present disclosure is not limited to the above-described embodiments, and various modifications can be made within the scope of the present disclosure.

[0080] 6, in the above embodiment, the second body portion 41 extends linearly along the X-axis, but may be bent or curved. For example, the second body portion 41 may be bent or curved so as to be spaced apart from the first body portion 31. In this case, a gap is formed between the first body portion 31 and the second body portion 41, and the magnetic coupling between the first body portion 31 and the second body portion 41 can be reduced.

[0081] In the above embodiment, an example of application of the present disclosure to a coupled inductor has been described, but the present disclosure may also be applied to other electronic components.

[0082] 3, the core in the above embodiment is composed of two cores, the first core 10 and the second core 20, but it may be composed of one core. Such a core can be formed, for example, by (1) placing the first conductor 30 and the second conductor 40 in a mold, (2) filling the mold with a core material that constitutes the core, and (3) compressing and hardening the core material.

[0083] 3, in the above embodiment, the groove 17 for accommodating the first body portion 31 and the second body portion 41 is formed in the first core 10. However, the groove for accommodating the first body portion 31 and the second body portion 41 may be formed in the second core 20. [Explanation of symbols]

[0084] 1...Coil device 10…First core 11…1st side 12…Second side 13…Third side 14…Fourth side 15...Mounting surface 16…Mounting surface 17…Groove 170…Bottom 171,172…Inner wall 18a, 18b...Concave portion 180...Side bottom surface 20…Second core 21...Abutment surface 30…First conductor 31...First main body part 32a, 32b…First mounting section 321…Bend 322...legs 33...Coating 40…Second conductor 41...Second body part 42a, 42b...Second mounting section 421…Bend 422...legs 423…Middle section 50...Magnetic coupling part 61,62…Gap 70…Adhesive

Claims

1. a core having a mounting surface; A first conductor formed of a wire; A second conductor formed of a conductor plate, the first conductor has a first body portion extending along the mounting surface inside the core, the second conductor extends along the mounting surface inside the core and has a second body portion facing the first body portion; A coil device in which, in a direction in which the first body portion and the second body portion oppose each other, the first body portion is located on one side of the core, and the first body portion and the second body portion are offset to the one side of the core where the first body portion is located.

2. The coil device according to claim 1 , wherein in a direction in which the first body portion and the second body portion face each other, the first body portion and the second body portion are located on one side of the core relative to a center of the core.

3. the first conductor has a first mounting portion exposed from the core, the second conductor has a second mounting portion exposed from the core, The coil device according to claim 1 , wherein the second mounting portion extends to the other side of the core so as to be spaced apart from the first mounting portion.

4. The coil device according to claim 3 , wherein the first mounting portion and the second mounting portion are disposed inside an outer edge of the core when viewed in a direction perpendicular to the mounting surface.

5. the core has a recess formed on a side surface of the core perpendicular to the mounting surface, The coil device according to claim 4 , wherein the first mounting portion and the second mounting portion are housed in the recess.

6. The coil device according to claim 1 , wherein a first width of the first body portion is different from a second width of the second body portion in a direction in which the first body portion and the second body portion face each other.

7. The coil device of claim 6 , wherein the first width is greater than the second width.

8. The coil device according to claim 1 , wherein a height position of the first body portion from the mounting surface is different from a height position of the second body portion from the mounting surface.

9. The coil device according to claim 1 , wherein the first body portion is in contact with the second body portion.

10. The coil device according to claim 1 , wherein the second conductor has a plating layer formed on at least a portion of the second conductor.

11. The coil device according to claim 1 , wherein the first conductor has an insulating coating layer formed on at least a portion of the first conductor.

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