Coil device

Abstract

To provide a magnetic coupling type coil device that has superior inductance characteristics and / or DC superposition characteristics.SOLUTION: A coil device 1 has a core which has a mount surface 15, a first conductor which has a first main body part 31 extending along the mount surface 15 in the core, and a second conductor which has a second main body part 41 extending along the mount surface 15 in the core and facing the first main body part 31. The first main body part 31 has a first side surface which has a first thickness in a direction perpendicular to the mount surface 15 and a first principal surface which has a first width in a direction parallel to the mount surface 15. The second main body part 41 has a second side surface which has a second thickness in the direction perpendicular to the mount surface 15 and a second principal surface which has a second width in the direction parallel to the mount surface 15. The second width is narrower than the first width in the direction in which the first main body part 31 and second main body part 41 face each other.SELECTED DRAWING: Figure 5

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 winding with a first intermediate portion having a flat surface, and a second winding with a second intermediate portion having a flat surface. The first intermediate portion and the second intermediate portion face each other at a predetermined distance and are magnetically coupled.

[0003] In the coil device of Patent Document 1, the first intermediate part and the second intermediate part are arranged parallel to the side surface of the core (the surface perpendicular to the mounting surface). By arranging the first intermediate part and the second intermediate part inside the core in such an orientation, the size of the core is reduced, and the coupled inductor can be made smaller and thinner.

[0004] In recent years, in order to further improve the response speed of voltage regulators, there is a demand for coupled inductors to not only be smaller, but also to have higher performance. In order to improve the response speed of voltage regulators, it is particularly necessary to further improve the inductance characteristics and / or DC superposition characteristics of the coupled inductors. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2018 / 0068778 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a coil device that is excellent in inductance characteristics and / or DC superposition characteristics. [Means for solving the problem]

[0007] In order to achieve the above object, the coil device of the present disclosure is: a core having a mounting surface; a first conductor having a first body portion extending along the mounting surface inside the core; a second conductor extending along the mounting surface inside the core and having a second body portion facing the first body portion; the first body portion has a first side surface having a first thickness in a direction perpendicular to the mounting surface and a first main surface having a first width in a direction parallel to the mounting surface; the second body portion has a second side surface having a second thickness in a direction perpendicular to the mounting surface and a second main surface having a second width in a direction parallel to the mounting surface; In a direction in which the first body portion and the second body portion face each other, the second width is narrower than the first width.

[0008] In the coil device of the present disclosure, the first body has a first side surface having a first thickness in a direction perpendicular to the mounting surface and a first main surface having a first width in a direction parallel to the mounting surface. The second body has a second side surface having a second thickness in a direction perpendicular to the mounting surface and a second main surface having a second width in a direction parallel to the mounting surface. The first body and the second body are disposed inside the core such that the first side surface, the second side surface, the first main surface, and the second main surface are oriented in the above-mentioned directions, thereby reducing the size of the core and making the coil device smaller and lower-profile. In addition, since the first body and the second body are opposed to each other, magnetic coupling between the first body and the second body can be ensured.

[0009] In particular, in the coil device of the present disclosure, the second width is narrower than the first width in the direction in which the first body portion and the second body portion face each other. Therefore, compared to when the first width and the second width are equal, more core arrangement space (space corresponding to the difference between the first width and the second width) is formed around the second body portion. This increases the volume of the core around the second body portion, improving the inductance characteristics and / or DC superposition characteristics of the coil device. In addition, since the first width and the second width are different, the first body portion and the second body portion have resistance values ​​different from each other. This makes it possible to adjust the inductance characteristics and / or DC superposition characteristics of the coil device according to the resistance value of the first body portion or the second body portion.

[0010] The first side surface and the second side surface may be perpendicular to the mounting surface. In this case, the first side surface and the second side surface can be arranged parallel to the side surface of the core (the surface perpendicular to the mounting surface). This makes it possible to form more space for arranging the core around the first side surface and the second side surface. This further improves the inductance characteristics and / or the DC superposition characteristics of the coil device.

[0011] The first conductor has a first mounting portion continuous with the first body portion, and the second conductor has a second mounting portion continuous with the second body portion, and the cross-sectional area of ​​the first mounting portion or the second mounting portion may be larger than the cross-sectional area of ​​the second body portion and smaller than the cross-sectional area of ​​the first body portion. In this case, it is possible to ensure a contact area between the first mounting portion or the second mounting portion and the mounting board. Therefore, the mounting stability of the coil device is improved.

[0012] The first mounting portion may have a third width in the axial direction of the first body portion and a fourth width in the direction in which the first body portion and the second body portion face each other, the first thickness, the second thickness, and the fourth width being equal, the first thickness, the second thickness, and the fourth width being greater than the second width and less than the third width, and the third width being greater than the first thickness, the second thickness, and the fourth width and less than the first width. In particular, when the third width and the fourth width satisfy the above-mentioned magnitude relationship, the contact area between the first mounting portion and the mounting board is easily secured, and the mounting stability of the coil device is improved. In particular, when the first width and the second width satisfy the above-mentioned magnitude relationship, the volume of the core around the second body portion is easily secured, and the inductance characteristics and / or the DC superposition characteristics of the coil device are improved.

[0013] The first mounting portion may have a third width in the axial direction of the first body portion and a fourth width in the direction in which the first body portion and the second body portion face each other, and the second mounting portion may have a fifth width in the axial direction of the second body portion and a sixth width in the direction in which the first body portion and the second body portion face each other, the third width being equal to the fifth width, and the fourth width being equal to the sixth width. In this case, the cross-sectional area of ​​the first mounting portion and the cross-sectional area of ​​the second mounting portion are equal. Therefore, when the first mounting portion and the second mounting portion are arranged on a mounting board, the mounting stability of the coil device is improved.

[0014] The first body portion and the second body portion may form a magnetic coupling portion that is magnetically coupled to each other, and a center of the magnetic coupling portion may be located at a center of the core in a direction in which the first body portion and the second body portion face each other. In this case, the balance of the volume of the core is improved around the first body portion and the second body portion, and the saturation magnetic flux density of the core is easily made uniform.

[0015] The ratio of the first width to the second width may be 3:1 to 4:1. In this case, the inductance characteristics and / or DC bias characteristics of the coil device are particularly improved.

[0016] The first conductor may have a first mounting portion continuous with the first body portion and exposed from the core, and the second conductor may have a second mounting portion continuous with the second body portion and exposed from the core, and the first mounting portion and the second mounting portion may extend toward the mounting surface of the core while being spaced apart from each other along the direction in which the first body portion and the second body portion face each other. By spaced apart from each other along the direction in which the first body portion and the second body portion face each other, the size of the coil device is reduced in the axial direction of the first body portion or the second body portion. This allows the coil device to be made more compact.

[0017] The first mounting portion has a first base end portion extending along the direction in which the first body portion and the second body portion face each other, and a first leg portion continuing from the first base end portion and extending toward the mounting surface, and the second mounting portion has a second base end portion extending on the opposite side to the first base end portion along the direction in which the first body portion and the second body portion face each other, and a second leg portion continuing from the second base end portion and extending toward the mounting surface, and the first mounting portion may be curved in an L-shape from the first base end portion to the first leg portion, and the second mounting portion may be curved in an L-shape from the second base end portion to the second leg portion. In this case, since the first base end portion and the second base end portion extend in opposite directions from each other along the direction in which the first body portion and the second body portion face each other, the size of the coil device can be reduced in the axial direction of the first body portion or the second body portion. In addition, since the first mounting portion and the second mounting portion are curved in an L-shape, the mounting stability is improved when the coil device is mounted. [Brief description of the drawings]

[0018] [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

[0019] 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.

[0020] 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.

[0021] 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.

[0022] The width of the coil device 1 in the X-axis direction is not particularly limited, but is, for example, 2.0 to 20.0 mm. The width of the coil device 1 in the Y-axis direction is not particularly limited, but is, for example, 2.0 to 10.0 mm. The thickness of the coil device 1 in the Z-axis direction is not particularly limited, but is, for example, 2.0 to 10.0 mm.

[0023] 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.

[0024] The first core 10 has a groove 17 formed in the mounting surface 16. The groove 17 is located at the center in the Y-axis direction and extends along the X-axis from one end to the other end of the mounting surface 16 in the X-axis direction.

[0025] The groove portion 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. In this embodiment, "parallel" is not limited to strictly parallel. Furthermore, "vertical" is not limited to strictly vertical.

[0026] 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.

[0027] 3, the second core 20 has a rectangular parallelepiped shape. 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.

[0028] 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.

[0029] The width of the second core 20 in the X-axis direction is, but is not particularly limited to, wider than the 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 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.

[0030] The first conductor 30 and the second conductor 40 shown in Fig. 4 are formed by a metal frame. The first conductor 30 and the second conductor 40 are 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 first conductor 30 and the second conductor 40 have higher rigidity than general wires (round wire, rectangular wire, etc.). The material constituting the first conductor 30 and the second conductor 40 is not particularly limited, but may be, for example, copper, a copper alloy, silver, or nickel.

[0031] A plating film (plating layer) is formed on at least a portion (in this embodiment, the entire surface) of the first conductor 30. Also, a plating film (plating layer) is formed on at least a portion (in this embodiment, the entire surface) of the second conductor 40. 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.

[0032] 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.

[0033] 4, the first conductor 30 has a first body portion 31 and first mounting portions 32a and 32b. The first body portion 31 is elongated and extends linearly along the X-axis. The cross-sectional shape of the first body portion 31 is rectangular, but may be a square, another polygon, or another shape.

[0034] The first main body portion 31 has two side surfaces (first side surfaces) and two main surfaces (first main surfaces). The first main body portion 31 has a first outer side surface 310 and a first inner side surface 311 as the first side surfaces. The first main body portion 31 also has a first top surface 312 and a first bottom surface 313 as the first main surfaces.

[0035] The first outer surface 310 and the first inner surface 311 are located on opposite sides along the Y axis and are parallel to each other. The first outer surface 310 is located outward in the Y axis direction from the first inner surface 311. The first top surface 312 and the first bottom surface 313 are located on opposite sides along the Z axis and are parallel to each other. The first outer surface 310, the first inner surface 311, the first top surface 312, and the first bottom surface 313 are flat surfaces perpendicular to each other.

[0036] However, at least one of the first outer surface 310, the first inner surface 311, the first top surface 312, and the first bottom surface 313 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 first outer surface 310 in this embodiment is perpendicular to the XY plane (i.e., the mounting surface 15 in FIG. 3), but may be an inclined surface inclined at a predetermined angle (for example, 30° or more and less than 90°) with respect to the mounting surface 15.

[0037] 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.

[0038] 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 base end 320, a curved portion 321, and a leg portion 322.

[0039] The base end 320 is continuous with the first main body portion 31 and extends along the Y axis so as to be perpendicular to the first main body portion 31. The curved portion 321 is curved in an L shape between the base end 320 and the leg portion 322. The leg portion 322 extends linearly along the Z axis. The leg portion 322 is perpendicular to the base end portion 320. When viewed from the X axis direction, the leg portion 322 is located outside the first main body portion 31 in the Y axis direction. The cross-sectional shape of the leg portion 322 is rectangular, but may be a square, another polygon, or another shape.

[0040] The second conductor 40 has a second main body portion 41 and second mounting portions 42a and 42b. The second main body portion 41 is elongated and extends linearly along the X-axis. The cross-sectional shape of the second main body portion 41 is rectangular, but may be a square, another polygon, or another shape.

[0041] The second main body portion 41 has two side surfaces (second side surfaces) and two main surfaces (second main surfaces). The second main body portion 41 has a second outer side surface 410 and a second inner side surface 411 as the second side surfaces. The second main body portion 41 also has a second top surface 412 and a second bottom surface 413 as the second main surfaces.

[0042] The second outer surface 410 and the second inner surface 411 are located on opposite sides along the Y axis and are parallel to each other. The second outer surface 410 is located outward in the Y axis direction from the second inner surface 411. The second top surface 412 and the second bottom surface 413 are located on opposite sides along the Z axis and are parallel to each other. The second outer surface 410, the second inner surface 411, the second top surface 412, and the second bottom surface 413 are flat surfaces perpendicular to each other.

[0043] However, at least one of the second outer surface 410, the second inner surface 411, the second top surface 412, and the second bottom surface 413 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 second outer surface 410 in this embodiment is perpendicular to the XY plane (i.e., the mounting surface 15 in FIG. 3), but may be an inclined surface inclined at a predetermined angle (for example, 30° or more and less than 90°) with respect to the mounting surface 15.

[0044] 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 dashed lines. The shape of the second mounting portion 42a is the same as the shape of the second mounting portion 42b, but may be different.

[0045] The second mounting parts 42a and 42b have an L-shaped bent shape. The second mounting parts 42a and 42b are connected to a mounting board by solder, conductive adhesive, etc. The second mounting parts 42a and 42b each have a base end 420, a curved part 421, and a leg part 422.

[0046] The base end 420 is continuous with the second main body portion 41 and extends along the Y axis so as to be perpendicular to the second main body portion 41. The curved portion 421 is curved in an L shape between the base end 420 and the leg portion 422. The leg portion 422 extends linearly along the Z axis. The leg portion 422 is perpendicular to the base end portion 420. When viewed from the X axis direction, the leg portion 422 is located outside the second main body portion 41 in the Y axis direction. The cross-sectional shape of the leg portion 422 is rectangular, but may be a square, another polygon, or another shape.

[0047] 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 bottom surface 313 of 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 bottom surface 413 of the second body portion 41 is bonded to the bottom surface 170 of the groove portion 17 by the adhesive 70. However, the first top surface 312 of the first body portion 31 may be bonded to the abutment surface 21 of the second core 20 by the adhesive 70. Also, the second top surface 412 of the second body portion 41 may be bonded to the abutment surface 21 of the second core 20 by the adhesive 70.

[0048] The first inner side surface 311 and the second inner side surface 411 face each other along the Y axis at a predetermined interval. A distance W0 between the first inner side surface 311 and the second inner side surface 411 along the Y axis is not particularly limited, but is, for example, 0.05 to 0.5 mm. The magnetic coupling between the first main body portion 31 and the second main body portion 41 can be adjusted according to the size of the distance W0. A gap 60 is formed between the first inner side surface 311 and the second inner side surface 411.

[0049] The gap 60 is an air gap. However, the gap 60 may be filled with an adhesive. For example, in order to set the interval W0 to a predetermined value, the first inner side surface 311 and the second inner side surface 411 may be bonded with an adhesive (for example, an adhesive containing beads). Alternatively, a part of the first core 10 or the second core 20 may be disposed in the gap 60. Alternatively, a partition member (spacer) or a film formed of a non-conductive member such as a resin may be disposed in the gap 60.

[0050] A gap 61 is formed between the first outer surface 310 and the inner wall 171 of the groove portion 17, but the first outer surface 310 may be in contact with the inner wall 171. Alternatively, the first outer surface 310 and the inner wall 171 may be bonded together with an adhesive.

[0051] Furthermore, a gap 62 is formed between the second outer surface 410 and the inner wall 172 of the groove portion 17, but the second outer surface 410 may be in contact with the inner wall 172. Alternatively, the second outer surface 410 and the inner wall 172 may be bonded together with an adhesive.

[0052] 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. A gap is formed between the first top surface 312 of the first body portion 31 and the abutment surface 21 of the second core 20, but they may be in contact. Also, a gap is formed between the second top surface 412 of the second body portion 41 and the abutment surface 21 of the second core 20, but they may be in contact.

[0053] The first body 31 and the second body 41 constitute a magnetic coupling unit 50 that is magnetically coupled to each other. The magnetic coupling unit 50 is a virtual structure in which the first body 31 and the second body 41 are regarded as one configuration. In the Y-axis direction, the center C of the magnetic coupling unit 50 is located at the center of the first core 10 and / or the second core 20. However, the position of the center C of the magnetic coupling unit 50 in the Y-axis direction does not have to completely match the position of the center of the first core 10 and / or the second core 20 in the Y-axis direction. The center C of the magnetic coupling unit 50 may be located within a range of a predetermined length along the Y-axis from the center of the first core 10 and / or the second core 20. However, the predetermined length is 5% of the width of the first core 10 or the second core 20 in the Y-axis direction.

[0054] In this embodiment, the center of the magnetic coupling part 50 is located at the center of the first core 10. Therefore, the balance of the volume of the first core 10 is improved around the first main body part 31 (for example, the outside in the Y-axis direction of the first outer side surface 310) and around the second main body part 41 (for example, the outside in the Y-axis direction of the second outer side surface 410), and the saturation magnetic flux density of the first core 10 is easily made uniform.

[0055] 6, the first mounting portion 32a is disposed on the outer side of the first core 10 in the X-axis direction and adjacent to the third side surface 13. The first mounting portion 32b is disposed on the outer side of the first core 10 in the X-axis direction and adjacent to the fourth side surface 14. The first mounting portions 32a and 32b are disposed on both sides of the first core 10 in the X-axis direction so as to sandwich the first core 10 from both sides in the X-axis direction.

[0056] The first mounting portions 32a and 32b are exposed from the first core 10 and the second core 20. The first mounting portions 32a and 32b are covered from above by the second core 20, which is indicated by a 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.

[0057] Moreover, the second mounting portion 42a is disposed on the outside of the first core 10 in the X-axis direction and adjacent to the third side surface 13. Moreover, the second mounting portion 42b is disposed on the outside of the first core 10 in the X-axis direction and adjacent to the fourth side surface 14. The second mounting portions 42a and 42b are disposed on both sides of the first core 10 in the X-axis direction so as to sandwich the first core 10 from both sides in the X-axis direction.

[0058] The second mounting portions 42a and 42b are exposed from the first core 10 and the second core 20. The second mounting portions 42a and 42b are covered from above by the second core 20, which is indicated by a 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.

[0059] 5, 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.

[0060] 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.

[0061] 4 and 5, the first outer surface 310 has a first thickness T1 in a direction (Z-axis direction) perpendicular to the XY plane (mounting surface 15). The first inner surface 311 also has a first thickness T1 in the same direction. The first top surface 312 has a first width W1 in a direction (Y-axis direction) parallel to the XY plane (mounting surface 15). The first bottom surface 313 also has a first width W1 in the same direction.

[0062] The second outer surface 410 has a second thickness T2 in a direction (Z-axis direction) perpendicular to the XY plane (mounting surface 15). The second inner surface 411 also has a second thickness T2 in the same direction. The second top surface 412 has a second width W2 in a direction (Y-axis direction) parallel to the XY plane (mounting surface 15). The second bottom surface 413 also has a second width W2 in the same direction.

[0063] In the direction in which the first body portion 31 and the second body portion 41 face each other (the Y-axis direction), the second width W2 is narrower than the first width W1. Therefore, compared to when the first width W1 and the second width W2 are equal, a larger arrangement space for the first core 10 (a space corresponding to the difference between the first width W1 and the second width W2) is formed around the second body portion 41. As a result, the volume of the first core 10 is increased around the second body portion 41 (for example, outside the second outer surface 410 in the Y-axis direction), and the inductance characteristics and / or the DC superposition characteristics of the coil device 1 are improved.

[0064] In addition, since the first width W1 and the second width W2 are different, the first body portion 31 and the second body portion 41 have different resistance values. This makes it possible to adjust the inductance characteristics and / or the DC superposition characteristics of the coil device 1 according to the resistance value of the first body portion 31 or the second body portion 41.

[0065] 4 and 5, the size of the first core 10 is reduced, and the coil device 1 can be made smaller and lower in height. Moreover, since the first body portion 31 and the second body portion 41 are opposed to each other, magnetic coupling between the first body portion 31 and the second body portion 41 can be ensured.

[0066] The ratio of the first width W1 to the second width W2 is not particularly limited, but is 2:1 to 5:1, or 3:1 to 4:1. In this case, the inductance characteristics and / or DC superposition characteristics of the coil device 1 are particularly improved.

[0067] Moreover, the first side surface 310 and the second side surface 410 are perpendicular to the mounting surface 15. Therefore, the first outer side surface 310 is arranged parallel to the second side surface 12 (a surface perpendicular to the mounting surface 15) of the first core 10. Furthermore, the second outer side surface 410 is arranged parallel to the first side surface 11 (a surface perpendicular to the mounting surface 15) of the first core 10. This makes it possible to form more arrangement space for the first core 10 around the first outer side surface 310 and the second outer side surface 410. Therefore, the inductance characteristics and / or DC superposition characteristics of the coil device 1 are further improved.

[0068] The first mounting portion 32a (leg portion 322) has a third width W3 along the axial direction (X-axis direction) of the first main body portion 31. In addition, the first mounting portion 32a (leg portion 322) has a fourth width W4 along the direction in which the first main body portion 31 and the second main body portion 41 face each other (Y-axis direction). The first mounting portion 32b is similar and has the third width W3 and the fourth width W4 in the same direction.

[0069] The second mounting portion 42a (leg portion 422) has a fifth width W5 along the axial direction (X-axis direction) of the second main body portion 41. Moreover, the second mounting portion 42b (leg portion 422) has a sixth width W6 along the direction in which the first main body portion 31 and the second main body portion 41 face each other (Y-axis direction). Similarly, the second mounting portion 42b has a fifth width W5 and a sixth width W6 in the same direction.

[0070] The third width W3 is equal to the fifth width W5. The fourth width W4 is equal to the sixth width W6. Therefore, the cross-sectional area of ​​the first mounting portion 32a is equal to the cross-sectional area of ​​the second mounting portion. This improves the mounting stability of the coil device 1 when the first mounting portion 32a and the second mounting portion 42a are arranged on a mounting board.

[0071] The first thickness T1, the second thickness T2, and the fourth width W4 are equal. Moreover, the first thickness T1, the second thickness T2, and the fourth width W4 are greater than the second width W2 and are equal to or less than the third width W3. Moreover, the third width W3 is equal to or greater than the first thickness T1, the second thickness T2, and the fourth width W4, and is equal to or less than the first width W1. In particular, when the third width W3 and the fourth width W4 satisfy the above-mentioned magnitude relationship, the contact area between the first mounting portion 32a and the mounting board is easily secured, and the mounting stability of the coil device 1 is improved. In particular, when the first width W1 and the second width W2 satisfy the above-mentioned magnitude relationship, the volume of the first core 10 around the second main body portion 41 is easily secured, and the inductance characteristics and / or the DC superposition characteristics of the coil device 1 are improved.

[0072] The first thickness T1, the second thickness T2, and the sixth width W6 are equal. Moreover, the first thickness T1, the second thickness T2, and the sixth width W6 are greater than the second width W2 and are equal to or less than the fifth width W5. Moreover, the fifth width W5 is equal to or greater than the first thickness T1, the second thickness T2, and the sixth width W6, and is equal to or less than the first width W1. In particular, when the fifth width W5 and the sixth width W6 satisfy the above-mentioned magnitude relationship, the contact area between the second mounting portion 42a and the mounting board is easily secured, and the mounting stability of the coil device 1 is improved. In particular, when the first width W1 and the second width W2 satisfy the above-mentioned magnitude relationship, the volume of the first core 10 around the second main body portion 41 is easily secured, and the inductance characteristics and / or the DC superposition characteristics of the coil device 1 are improved.

[0073] The cross-sectional area (W3×W4) of the first mounting portion 32a is larger than the cross-sectional area (T2×W2) of the second main body portion 41 and is equal to or smaller than the cross-sectional area (T1×W1) of the first main body portion 31. The same applies to the cross-sectional area of ​​the first mounting portion 32b. The cross-sectional area (W5×W6) of the second mounting portion 42a is larger than the cross-sectional area (T2×W2) of the second main body portion 41 and is equal to or smaller than the cross-sectional area (T1×W1) of the first main body portion 31. The same applies to the cross-sectional area of ​​the second mounting portion 42b. Therefore, the contact area between the first mounting portion 32a and / or the second mounting portion 42a and the mounting board can be secured. This improves the mounting stability of the coil device 1.

[0074] As shown in FIG. 3, the first mounting portion 32a and the second mounting portion 42a extend toward the mounting surface 15 of the first core 10 while being spaced apart from each other along the direction in which the first body portion 31 and the second body portion 41 face each other (i.e., the Y-axis direction). The first mounting portion 32b and the second mounting portion 42b extend toward the mounting surface 15 of the first core 10 while being spaced apart from each other along the direction in which the first body portion 31 and the second body portion 41 face each other (i.e., the Y-axis direction). By spaced apart from each other along the Y-axis direction, the size of the coil device 1 is reduced in the axial direction (X-axis direction) of the first body portion 31 or the second body portion 41. This allows the coil device 1 to be made smaller.

[0075] 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 first bottom surface 313 (FIG. 4) of the first main body portion 31 is bonded to the groove portion 17 of the first core 10 by an adhesive. Also, the second bottom surface 413 (FIG. 4) of the second main body portion 41 is bonded to the groove portion 17 by an adhesive. At this time, a space is provided between the first main body portion 31 and the second main body portion 41 so that a gap 60 shown in FIG. 5 is formed between the first main body portion 31 and the second main body portion 41. Also, as shown in FIG. 3, the first mounting portions 32a and 32b are disposed on the outer side of the first core 10 in the X-axis direction, and the second mounting portions 42a and 42b are disposed on the outer side of the first core 10 in the X-axis direction. Next, the contact surface 21 of the second core 20 shown in Fig. 3 is bonded with an adhesive to the opposing mounting surface 16 of the first core 10 shown in Fig. 2. In this manner, the coil device 1 shown in Fig. 1 can be manufactured.

[0076] 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.

[0077] For example, 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.

[0078] 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.

[0079] 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.

[0080] As long as the second width W2 shown in FIG. 4 is smaller than the first width W1, the dimensions of the first conductor 30 and the second conductor 40 are not particularly limited. For example, in the above embodiment, the first thickness T1, the second thickness T2, and the fourth width W4 are equal, but the first thickness T1 and the second thickness T2 may be different from the fourth width W4. Also, the first thickness T1 and the second thickness T2 may be different. In this case, the same effect as in the above embodiment can be obtained.

[0081] In the above embodiment, the first thickness T1, the second thickness T2, and the fourth width W4 are greater than the second width W2 and less than the third width W3, but the first thickness T1, the second thickness T2, and the fourth width W4 may be less than the second width W2. The first thickness T1, the second thickness T2, and the fourth width W4 may be greater than or equal to the third width W3. In this case, the same effect as in the above embodiment can be obtained.

[0082] In the above embodiment, the third width W3 is equal to or larger than the first thickness T1, the second thickness T2, and the fourth width W4, and is equal to or smaller than the first width W1. However, the third width W3 may be smaller than the first thickness T1, the second thickness T2, and the fourth width W4. The third width W3 may be larger than the first width W1. In this case, the same effect as in the above embodiment can be obtained.

[0083] 4, in the above embodiment, the third width W3 is equal to the fifth width W5, but the third width W3 may be different from the fifth width W5. Also, the fourth width W4 is equal to the sixth width W6, but the fourth width W4 may be different from the sixth width W6. [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 20…Second core 21...Abutment surface 30…First conductor 31...First main body part 310…First outer surface 311…First inner surface 312...1st top surface 313...1st bottom surface 32a, 32b…First mounting section 320…Proximal end 321…Bend 322...legs 40…Second conductor 41...Second body part 410…First outer surface 411…First inner surface 412...1st top surface 413...1st bottom surface 42a, 42b…First mounting section 420...Proximal end 421…Bend 422...legs 50...Magnetic coupling part 60~62…Gap 70…Adhesive

Claims

1. a core having a mounting surface; a first conductor having a first body portion extending along the mounting surface inside the core; a second conductor extending along the mounting surface inside the core and having a second body portion facing the first body portion, the first body portion has a first side surface having a first thickness in a direction perpendicular to the mounting surface and a first main surface having a first width in a direction parallel to the mounting surface; the second body portion has a second side surface having a second thickness in a direction perpendicular to the mounting surface and a second main surface having a second width in a direction parallel to the mounting surface; A coil device, wherein the second width is narrower than the first width in a direction in which the first body portion and the second body portion face each other.

2. The coil device according to claim 1 , wherein the first side surface and the second side surface are perpendicular to the mounting surface.

3. the first conductor has a first mounting portion continuous with the first body portion, the second conductor has a second mounting portion continuous with the second body portion, The coil device according to claim 1 or 2, wherein a cross-sectional area of ​​the first mounting portion or the second mounting portion is larger than a cross-sectional area of ​​the second main body portion and is equal to or smaller than a cross-sectional area of ​​the first main body portion.

4. the first mounting portion has a third width in an axial direction of the first body portion and a fourth width in a direction in which the first body portion and the second body portion face each other; the first thickness, the second thickness, and the fourth width are equal; the first thickness, the second thickness, and the fourth width are greater than the second width and less than or equal to the third width; The coil device according to claim 3 , wherein the third width is greater than or equal to the first thickness, the second thickness and the fourth width, and is less than or equal to the first width.

5. the first mounting portion has a third width in an axial direction of the first body portion and a fourth width in a direction in which the first body portion and the second body portion face each other; the second mounting portion has a fifth width in an axial direction of the second body portion and a sixth width in a direction in which the first body portion and the second body portion face each other; the third width is equal to the fifth width; The coil device according to claim 3 , wherein the fourth width is equal to the sixth width.

6. The first body portion and the second body portion configure a magnetic coupling portion that is magnetically coupled to each other, The coil device according to claim 1 , wherein a center of the magnetic coupling portion is located at a center of the core in a direction in which the first body portion and the second body portion face each other.

7. 3. The coil device according to claim 1, wherein a ratio of the first width to the second width is 3:1 to 4:

1.

8. the first conductor has a first mounting portion that is continuous with the first body portion and is exposed from the core, the second conductor has a second mounting portion that is continuous with the second body portion and is exposed from the core, The coil device according to claim 1 or 2, wherein the first mounting portion and the second mounting portion extend toward the mounting surface side of the core while being spaced apart from each other along the direction in which the first main body portion and the second main body portion face each other.

9. the first mounting portion has a first base end portion extending along a direction in which the first main body portion and the second main body portion face each other, and a first leg portion continuing from the first base end portion and extending toward the mounting surface, the second mounting portion has a second base end portion extending on an opposite side to the first base end portion along a direction in which the first main body portion and the second main body portion face each other, and a second leg portion continuing from the second base end portion and extending toward the mounting surface, the first mounting portion is curved in an L-shape from the first base end portion to the first leg portion, The coil device according to claim 8 , wherein the second mounting portion is curved in an L-shape from the second base end portion to the second leg portion.

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