Coil device

Abstract

To provide a coil device capable of reducing insertion loss due to leakage flux.SOLUTION: A coil device 1 has: a core 10 having a winding core part 11 and a flange part 12a which is formed at an end in an axial direction of the winding core part 11; a plate-like core 30 fitted to the core 10; a first wire 50 wound around the winding core part 11; a second wire 60 which is wound around the winding core part 11 so as to make a pair with the first wire 50; a first terminal electrode 70a which is provided at least on a mounting surface of the flange part 12a; and a second terminal electrode 80a, at least provided on the mounting surface, which is located away from the first terminal electrode 70a. Between the first terminal electrode 70a and the second terminal electrode 80a, the flange part 12a has a recessed part 20a which is recessed from the mounting surface. A bottom surface 200 of the recessed part 20a is flush with an outer peripheral surface 110 of the winding core part 11. The pair of the first wire 50 and the second wire 60 has a plurality of turns which are located away from one another along the axial direction.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to a coil device. [Background technology]

[0002] Patent Document 1 discloses a technique related to a coil device applicable to a common mode filter. The coil device of Patent Document 1 is a surface-mounted electronic component and includes a drum core and a plate-shaped core attached to the drum core. The drum core includes a winding core and a flange formed at the axial end of the winding core. A first wire and a second wire are wound around the winding core. A first terminal electrode and a second terminal electrode are provided spaced apart from each other on the mounting surface of the flange. An end of the first wire is connected to the first terminal electrode, and an end of the second wire is connected to the second terminal electrode. The plate-shaped core is attached to the surface opposite to the mounting surface of the flange.

[0003] In the coil device of Patent Document 1, the magnetic flux generated from the first wire and the second wire ideally passes through a circular path that connects the winding core portion, the flange portion at one axial end of the winding core portion, the plate-shaped core, and the flange portion at the other axial end of the winding core portion in the shortest distance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-99587 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in reality, part of the magnetic flux generated from the first wire and the second wire does not pass through the above-mentioned ideal path, but diffuses to a position deviating from the ideal path. This diffused part of the magnetic flux acts as leakage flux and can be a factor in increasing the insertion loss of the coil device.

[0006] The present disclosure provides a coil device capable of reducing insertion loss caused by leakage magnetic flux. [Means for solving the problem]

[0007] The coil device of the present disclosure is a core having a winding core portion and a flange portion formed at an axial end of the winding core portion; a plate-shaped core attached to the core; a first wire wound around the winding core; a second wire wound around the winding core to form a pair with the first wire; a first terminal electrode provided on at least the mounting surface of the flange; a second terminal electrode provided at least on the mounting surface and spaced apart from the first terminal electrode; the flange portion has a recess recessed from the mounting surface between the first terminal electrode and the second terminal electrode, a bottom surface of the recessed portion is flush with an outer peripheral surface of the winding core portion, The pair of first and second wires has a plurality of turns spaced apart from one another along the axial direction.

[0008] In the coil device of the present disclosure, the flange has a recess recessed from the mounting surface between the first terminal electrode and the second terminal electrode. Therefore, the recess blocks at least a portion of the path that diffuses magnetic flux toward the mounting surface of the flange, making it difficult for the magnetic flux to diffuse toward the mounting surface of the flange. This reduces leakage magnetic flux and increases the amount of magnetic flux passing through the path that connects the winding core, the flange, and the plate-shaped core in the shortest distance. Therefore, the insertion loss of the coil device caused by leakage magnetic flux can be reduced. Furthermore, the bottom surface of the recess is flush with the outer peripheral surface of the winding core. Therefore, no step is formed between the bottom surface of the recess and the outer peripheral surface of the winding core, preventing magnetic flux from concentrating at the step, which is a cause of insertion loss.

[0009] The second wire is wound around the winding core to form a pair with the first wire. The pair of the first and second wires has multiple turns spaced apart from each other along the axial direction. This improves the coupling between the first and second wires and reduces leakage flux. Furthermore, the stray capacitance between adjacent turns along the axial direction is reduced. This further reduces the insertion loss of the coil device due to leakage flux.

[0010] The flange portion may have an inner end surface connected to the winding core portion and an outer end surface opposite the inner end surface along the axial direction, and the recess may extend from the inner end surface to the outer end surface along the axial direction.

[0011] The first wire may have a first lead-out portion drawn from the winding core portion toward the flange portion, and the second wire may have a second lead-out portion drawn from the winding core portion toward the flange portion, the first lead-out portion being drawn from the winding core portion to the first terminal electrode while in contact with the core, and the second lead-out portion being drawn from the winding core portion to the second terminal electrode while in contact with the core.

[0012] The first draw-out portion may have a first straight portion passing through the recess along the axial direction and a first rising portion extending in a direction perpendicular to the axial direction in a plan view and rising from a bottom surface of the recess toward the mounting surface, and the second draw-out portion may have a second straight portion passing through the recess along the axial direction and a second rising portion extending in a direction perpendicular to the axial direction in a plan view and rising from the bottom surface of the recess toward the mounting surface.

[0013] The first lead-out portion may have a straight portion passing through the recess along the axial direction and a first rising portion extending in a direction perpendicular to the axial direction in a plan view and rising from a bottom surface of the recess toward the first terminal electrode, and the second lead-out portion may have an inclined portion passing through the recess obliquely with respect to the axial direction and a second rising portion extending in a direction perpendicular to the axial direction in a plan view and rising from the bottom surface of the recess toward the second terminal electrode.

[0014] The flange portion may have a first inclined surface and a second inclined surface, and the first inclined surface may be inclined from the bottom surface of the recess toward the mounting surface on one side of a direction perpendicular to the axial direction in a planar view, and the second inclined surface may be inclined from the bottom surface of the recess toward the mounting surface on the other side of a direction perpendicular to the axial direction in a planar view.

[0015] The flange portion may have a first inner wall surface and a second inner wall surface, the first inner wall surface rising perpendicularly from a bottom surface of the recess toward the mounting surface on one side in a direction perpendicular to the axial direction in a plan view, and the second inner wall surface rising perpendicularly from the bottom surface of the recess toward the mounting surface on the other side in a direction perpendicular to the axial direction in a plan view, the first inner wall surface being located inside the flange portion in the axial direction and the first inclined surface being located outside the flange portion, and the second inner wall surface being located inside the flange portion in the axial direction and the second inclined surface being located outside the flange portion in the axial direction.

[0016] The flange portion may have an inner end surface connected to the winding core portion and an outer end surface opposite the inner end surface along the axial direction, and a first connection position between the first lead portion and the first terminal electrode may be closer to the inner end surface than to the outer end surface, and a second connection position between the second lead portion and the second terminal electrode may be closer to the inner end surface than to the outer end surface.

[0017] The mounting surface may consist of a first region in which the first terminal electrode is provided and a second region in which the second terminal electrode is provided, the recess is located between the first region and the second region, the first region has a first exposed portion located between the first terminal electrode and the recess, the second region has a second exposed portion located between the second terminal electrode and the recess, and the mounting surface may be exposed in the first exposed portion and the second exposed portion. [Brief explanation of the drawings]

[0018] [Figure 1A] FIG. 1A is a perspective view of a coil device according to a first embodiment. [Figure 1B] FIG. 1B is a plan view of the coil device shown in FIG. 1A. [Figure 1C] FIG. 1C is a side view of the coil device shown in FIG. 1A as viewed from the X-axis direction. [Figure 1D] FIG. 1D is a side view of the coil device shown in FIG. 1A as viewed from the Y-axis direction. [Figure 2] FIG. 2 is a perspective view of a core of the coil device shown in FIG. 1A. [Figure 3A] FIG. 3A is a graph showing frequency characteristics of leakage inductance of the coil device shown in FIG. 1A. [Figure 3B] FIG. 3B is a graph showing frequency characteristics of insertion loss of the coil device shown in FIG. 1A. [Figure 4A] FIG. 4A is a perspective view of a coil device according to the second embodiment. [Figure 4B] FIG. 4B is a plan view of the coil device shown in FIG. 4A. [Figure 5] FIG. 5 is a plan view of the coil device according to the third embodiment. [Figure 6] FIG. 6 is a perspective view of a coil device according to the fourth embodiment. [Figure 7] FIG. 7 is a plan view of a modified example of the coil device of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the contents shown in the drawings are merely schematic and illustrative for understanding the present disclosure, and the appearance and dimensional ratios may differ from the actual product. Furthermore, the present disclosure is not limited to the following embodiments.

[0020] First embodiment 1A, the coil device 1 of the first embodiment is a surface-mounted electronic component that functions as a common mode filter, a pulse transformer, a balun transformer, etc. The coil device 1 is mounted, for example, in a signal circuit of a communication device, etc. The coil device 1 has a core 10, a plate-shaped core 30, a first wire 50, a second wire 60, terminal electrodes 70a and 70b, and terminal electrodes 80a and 80b.

[0021] The first wire 50 and the second wire 60 are, for example, insulated wires, each having a conductive core wire covered with an insulating coating. The first wire 50 and the second wire 60 are well-known wound wires such as AIW (polyamideimide copper wire), UEW (polyurethane copper wire), and PEW (polyester copper wire). The first wire 50 and the second wire 60 are round wires, but may also be square wires, twisted wires, Litz wires, braided wires, etc. The material constituting the first wire 50 and the second wire 60 is not particularly limited, but may be, for example, copper, copper alloy, silver, or nickel. The diameter of the first wire 50 or the second wire 60 is not particularly limited, but may be, for example, 10 to 100 μm. The diameter of the first wire 50 is equal to, or may be different from, the diameter of the second wire 60. The coating is stripped off at both ends of the first wire 50 or the second wire 60, exposing the conductive core wire.

[0022] The first wire 50 has a winding portion 51 and lead-out portions 52a and 52b. The winding portion 51 is formed by spirally winding the first wire 50 around the outer peripheral surface 110 of the winding core 11. The lead-out portion 52a is led out from the winding portion 51 and constitutes one end of the first wire 50. The lead-out portion 52b is led out from the winding portion 51 and constitutes the other end of the first wire 50.

[0023] The winding portion 61 is formed by spirally winding the second wire 60 around the outer peripheral surface 110 of the winding core portion 11. The second wire 60 is wound around the outer peripheral surface 110 to form a pair with the first wire 50. That is, the first wire 50 and the second wire 60 are bifilar wound. The first wire 50 and the second wire 60 may be in close contact with each other or may be spaced apart. The lead-out portion 62a is drawn out from the winding portion 61 and constitutes one end of the second wire 60. The lead-out portion 62b is drawn out from the winding portion 61 and constitutes the other end of the second wire 60.

[0024] The core 10 is formed of a material containing a magnetic material and a resin. The magnetic material constituting the core 10 is not particularly limited, but may be, for example, ferrite (Ni-Zn ferrite, Mn-Zn ferrite, etc.) or a metallic magnetic material (Fe-Ni alloy, Fe-Si alloy, Fe-Si-Cr alloy, Fe-Co alloy, Fe-Si-Al alloy, amorphous iron, etc.). The resin constituting the core 10 is not particularly limited, but may be, for example, epoxy resin, phenol resin, polyester resin, polyurethane resin, polyimide resin, etc. The core 10 may be a sintered body of a metallic magnetic material.

[0025] As shown in Fig. 2, core 10 has winding core 11, flange 12a, and flange 12b. The cross-sectional shape of winding core 11 perpendicular to the axial direction is rectangular, but may be square, hexagonal, octagonal, or any other polygonal shape. Winding core 11 has outer peripheral surface 110 with a flat surface. Flange 12a is formed at one axial end of winding core 11, and flange 12b is formed at the other axial end of winding core 11.

[0026] Flange portion 12a has a mounting surface 13, an attachment surface 14, an inner end surface 15, an outer end surface 16, a first side surface 17, and a second side surface 18. Similarly, flange portion 12b has a mounting surface 13, an attachment surface 14, an inner end surface 15, an outer end surface 16, a first side surface 17, and a second side surface 18. Flanges 12a and 12b have the same shape, but may have different shapes.

[0027] The mounting surface 13 is a surface facing a mounting board (not shown). The attachment surface 14 is a surface facing the mounting surface 13. A plate-shaped core 30 (FIG. 1A) is attached to the attachment surface 14. The inner end surface 15 is a surface connected to the winding core portion 11. The outer end surface 15 is a surface facing the inner end surface 15. The first side surface 17 is a surface perpendicular to the attachment surface 14, the inner end surface 15, and the outer end surface 16. The second side surface 18 is a surface facing the first side surface 17 and perpendicular to the attachment surface 14, the inner end surface 15, and the outer end surface 16.

[0028] In the following, the axis along the direction in which the inner end surface 15 and the outer end surface 16 face each other is referred to as the X-axis. The axis along the direction in which the first side surface 17 and the second side surface 18 face each other is referred to as the Y-axis. The axis along the direction in which the mounting surface 13 and the attachment surface 14 face each other is referred to as the Z-axis. The X-axis is an axis along the axial direction of the winding core 11. The Y-axis is an axis along a direction perpendicular to the axial direction of the winding core 11 in a plan view.

[0029] In this disclosure, the positive side of the Z axis is referred to as "upward," and the negative side of the Z axis is referred to as "downward." However, upward in the Z axis direction does not necessarily coincide with upward in the vertical direction. Also, downward in the Z axis direction does not necessarily coincide with downward in the vertical direction.

[0030] Furthermore, in the present disclosure, "equal" or "identical" does not only refer to a state in which the physical quantities of the multiple objects being compared are strictly equal or identical, but also includes a state in which there is an error of ±Δ% or less (not particularly limited, for example, Δ=7, 5, or 3) between the physical quantities of the multiple objects being compared.

[0031] Furthermore, in the present disclosure, "parallel" does not only refer to strict parallelism, but also includes a state in which there is an error of ±Δθ° (not particularly limited, for example, Δθ=3) or less from strict parallelism. Furthermore, "perpendicular" or "orthogonal" does not only refer to strict perpendicular or orthogonal, but also includes a state in which there is an error of ±Δθ° (not particularly limited, for example, Δθ=3) or less from strict perpendicular or orthogonal.

[0032] The recesses 20a and 20b linearly extend (penetrate) from the inner end face 15 to the outer end face 16 along the X-axis direction. As shown in FIG. 1A, the recess 20a is recessed downward from the mounting surface 13 of the flange portion 12a between the first terminal electrode 70a (substrate connection portion 71a) and the second terminal electrode 80a (substrate connection portion 81a). The recess 20b is recessed downward from the mounting surface 13 of the flange portion 12b between the first terminal electrode 70b (substrate connection portion 71b) and the second terminal electrode 80b (substrate connection portion 81b).

[0033] As shown in FIG. 2, the mounting surface 13 of the flange portion 12a is divided by the recess 20a into a first region 131 which is a region on one side in the Y-axis direction and a second region 132 which is a region on the other side in the Y-axis direction. The recess 20a is located between the first region 131 and the second region 132 of the flange portion 12a. Also, the mounting surface 13 of the flange portion 12b is divided by the recess 20b into a first region 131 which is a region on one side in the Y-axis direction and a second region 132 which is a region on the other side in the Y-axis direction. The recess 20b is located between the first region 131 and the second region 132 of the flange portion 12b.

[0034] As shown in FIG. 1B, the width W1 of the recess 20a in the Y-axis direction (the same applies to the recess 20b) is narrower than the width W2 of the bobbin core portion 11 in the Y-axis direction. However, the width W1 of the recess 20a may be equal to the width W2 of the bobbin core portion 11, or may be larger than the width W2 of the bobbin core portion 11. From the viewpoint of effectively reducing the leakage magnetic flux of the coil device 1, it is preferable that W1 > W2 or W1 ≥ W2. On the other hand, from the viewpoint of effectively ensuring the strength of the core 10 (flange portions 12a and 12b), it is preferable that W1 < W2 or W1 ≤ W2.

[0035] The width W1 of the recess 20a is constant along the X-axis direction, but may be different. For example, the width W1 of the recess 20a may become narrower (wider) as it goes toward one side in the X-axis direction. Alternatively, the recess 20a may be provided with a narrow-width portion where the width W1 is relatively narrow and a wide-width portion where the width W1 is relatively wide.

[0036] The ratio W1 / W3 of the width W1 in the Y-axis direction of recess 20a (similarly for recess 20b) to the width W3 in the Y-axis direction of flange 12a is not particularly limited, but may be, for example, 1 / 8≦W1 / W3<1 or 1 / 4≦W1 / W3<1. By setting the value of W1 / W3 within the above range, the magnetic flux of first wire 50 and second wire 60 is less likely to diffuse toward mounting surface 13 of flange 12a, and is more likely to pass through a circular path that connects winding core 11, flange 12a, plate core 30, and flange 12b in the shortest distance. This reduces leakage magnetic flux of coil device 1.

[0037] The length L1 of recess 20a (and similarly for recess 20b) in the X-axis direction is equal to the length of flange portion 12a in the X-axis direction. The ratio L1 / L2 of the length L1 of recess 20a in the X-axis direction to the length (total length) L2 of core 10 in the X-axis direction is not particularly limited, but may be, for example, 1 / 10≦L1 / L2<1 / 2 or 1 / 8≦L1 / L2≦1 / 4. By setting the value of L1 / L2 within the above range, the leakage magnetic flux of coil device 1 can be reduced, as described above.

[0038] In the example shown in FIG. 1C , the depth D of the recess 20a (the same applies to the recess 20b) is smaller than half the height H of the flange portion 12a, but may be half the height H or greater. The depth D of the recess 20a corresponds to the length along the Z axis between the mounting surface 13 of the flange portion 12a and the bottom surface 200 of the recess 20a. In this embodiment, the length along the Z axis between the mounting surface 13 of the flange portion 12a and the bottom surface 200 of the recess 20a is equal to the length along the Z axis between the mounting surface 13 of the flange portion 12a and the outer peripheral surface 110 of the winding core portion 11 (however, the upper surface 111 of the outer peripheral surface 110 shown in FIG. 2).

[0039] As shown in FIG. 2, the bottom surface 200 of the recess 20a is flush with the outer peripheral surface 110 of the winding core 11 (however, the upper surface 111 of the outer peripheral surface 110). Furthermore, the bottom surface 200 of the recess 20b is flush with the outer peripheral surface 110 of the winding core 11 (however, the upper surface 111). That is, the bottom surface 200 and the outer peripheral surface 110 are flat (smoothly) continuous, and no step is formed between the bottom surface 200 and the outer peripheral surface 110. In this embodiment, a continuously flat surface is formed in the region along the X-axis direction from the outer end surface 16 of the flange 12a to the outer end surface 16 of the flange 12b (i.e., the bottom surface 200 of the recess 20a, the outer peripheral surface 110 of the winding core 11, and the bottom surface 200 of the recess 20b). Furthermore, the height position of the bottom surface 200 coincides with the height position of the outer peripheral surface 110 (however, the upper surface 111).

[0040] Although not particularly limited, the upper surface 111 of the outer peripheral surface 110 is a flat surface parallel to the mounting surface 13. The same applies to the lower surface of the outer peripheral surface 110 (the surface facing the upper surface 111). The side surfaces of the outer peripheral surface 111 (surfaces perpendicular to the upper surface 111) are flat surfaces parallel to the first side surface 17 and the second side surface 18. Furthermore, although not particularly limited, the bottom surfaces 200 of the recesses 20a and 20b are flat surfaces parallel to the mounting surface 13.

[0041] The flange portion 12a has a first inclined surface 21a, a second inclined surface 22a, a first inner wall surface 23a, a second inner wall surface 24a, a first protruding surface 25a, and a second protruding surface 26a. These surfaces are located on both sides of the recess 20a in the Y-axis direction. The flange portion 12b has a first inclined surface 21b, a second inclined surface 22b, a first inner wall surface 23b, a second inner wall surface 24b, a first protruding surface 25b, and a second protruding surface 26b. These surfaces are located on both sides of the recess 20b in the Y-axis direction.

[0042] The first inclined surface 21a is inclined (rising obliquely) from the bottom surface 200 of the recess 20a toward the first region 131 of the mounting surface 13 on one side in the Y axis direction. The second inclined surface 22a is inclined (rising obliquely) from the bottom surface 200 of the recess 20a toward the second region 132 of the mounting surface 13 on the other side in the Y axis direction. The first inclined surface 21b is inclined (rising obliquely) from the bottom surface 200 of the recess 20b toward the first region 131 of the mounting surface 13 on one side in the Y axis direction. The second inclined surface 22b is inclined (rising obliquely) from the bottom surface 200 of the recess 20b toward the second region 132 of the mounting surface 13 on the other side in the Y axis direction.

[0043] 1C, the angle θ1 that first inclined surface 21a (similarly to first inclined surface 21b) forms with the Y axis is not particularly limited, but is equal to or greater than 15° and less than 90°. The angle θ2 that first inclined surface 22a (similarly to second inclined surface 22b) forms with the Y axis is not particularly limited, but is equal to or greater than 15° and less than 90°.

[0044] 2, a portion of the first region 131 is cut by the first inclined surface 21a or 21b. Therefore, the shape of the first region 131 is L-shaped in a plan view. Furthermore, a portion of the second region 132 is cut by the first inclined surface 22a or 22b. Therefore, the shape of the second region 132 is L-shaped in a plan view.

[0045] The first inner wall surface 23a rises vertically from the bottom surface 200 of the recess 20a toward the first region 131 of the mounting surface 13 on one side in the Y axis direction. The second inner wall surface 24a rises vertically from the bottom surface 200 of the recess 20a toward the second region 132 of the mounting surface 13 on the other side in the Y axis direction. The first inner wall surface 23b rises vertically from the bottom surface 200 of the recess 20b toward the first region 131 of the mounting surface 13 on one side in the Y axis direction. The second inner wall surface 24b rises vertically from the bottom surface 200 of the recess 20b toward the second region 132 of the mounting surface 13 on the other side in the Y axis direction. The first inner wall surface 23a, the first inner wall surface 23b, the second inner wall surface 24a, and the second inner wall surface 24b are all perpendicular to the mounting surface 13.

[0046] In the X-axis direction, first inner wall surface 23a is located inside flange 12a (toward inner end surface 15), and first inclined surface 21a is located outside flange 12a (toward outer end surface 16). In addition, in the X-axis direction, second inner wall surface 24a is located inside flange 12a, and second inclined surface 22a is located outside flange 12a. In addition, in the X-axis direction, first inner wall surface 23b is located inside flange 12b, and first inclined surface 21b is located outside flange 12b. In addition, in the X-axis direction, second inner wall surface 24b is located inside flange 12b, and second inclined surface 22b is located outside flange 12b.

[0047] The width in the X-axis direction of first inner wall surface 23a (similarly to first inner wall surface 23b) is narrower than the width in the X-axis direction of first inclined surface 21a, but may be the same as or wider. The width in the X-axis direction of second inner wall surface 24a (similarly to second inner wall surface 24b) is narrower than the width in the X-axis direction of second inclined surface 22a, but may be the same as or wider.

[0048] The first protruding surface 25a is a surface perpendicular to the first inner wall surface 23a and the first region 131, and extends (protrudes) in a direction perpendicular to the first inclined surface 21a. The second protruding surface 26a is a surface perpendicular to the second inner wall surface 24a and the second region 132, and extends (protrudes) in a direction perpendicular to the second inclined surface 22a. The first protruding surface 25b is a surface perpendicular to the first inner wall surface 23b and the first region 131, and extends (protrudes) in a direction perpendicular to the first inclined surface 21b. The second protruding surface 26b is a surface perpendicular to the second inner wall surface 24b and the second region 132, and extends (protrudes) in a direction perpendicular to the second inclined surface 22b. When viewed in the X-axis direction, the shapes of the first protruding surface 25a, the first protruding surface 25b, the second protruding surface 26a, and the second protruding surface 26b are, but are not particularly limited to, triangular.

[0049] 1A and 2, the first terminal electrode 70a is provided on at least the mounting surface 13 (in this embodiment, the first region 131 and the outer end surface 16) of the flange portion 12a on one side in the Y-axis direction. The second terminal electrode 80a is provided on at least the mounting surface 13 (in this embodiment, the second region 132 and the outer end surface 16) of the flange portion 12a on the other side in the Y-axis direction, and is spaced apart from the first terminal electrode 70a along the Y-axis direction. The shape of the first terminal electrode 70a is the same as the shape of the first region 131, i.e., an L-shape, in a plan view. The shape of the second terminal electrode 80a is the same as the shape of the second region 132, i.e., an L-shape, in a plan view.

[0050] The first terminal electrode 70b is provided on at least the mounting surface 13 of the flange 12b (in this embodiment, the first region 131 and the outer end surface 16) on one side in the Y-axis direction. The second terminal electrode 80b is provided on at least the mounting surface 13 of the flange 12b (in this embodiment, the second region 132 and the outer end surface 16) on the other side in the Y-axis direction, and is spaced apart from the first terminal electrode 70b along the Y-axis direction. The shape of the first terminal electrode 70b is the same as the shape of the first region 131, i.e., L-shaped, in a plan view. The shape of the second terminal electrode 80b is the same as the shape of the second region 132, i.e., L-shaped, in a plan view.

[0051] The first terminal electrodes 70a and 70b have substrate connection portions 71a and 71b and side portions 72a and 72b, respectively. The second terminal electrodes 80a and 80b have substrate connection portions 81a and 81b and side portions 82a and 82b, respectively. The substrate connection portions 71a, 71b, 81a, and 81b are connected to land patterns on a mounting substrate (not shown), and are connected to the land patterns by, for example, solder or a conductive adhesive.

[0052] As shown in FIGS. 1A and 2, the substrate connection portion 71a or 71b is formed over the entire first region 131, but may be formed only in a part of the first region 131. The substrate connection portion 71a may be formed on the first inclined surface 21a in addition to the first region 131. The substrate connection portion 71b may be formed on the first inclined surface 21b in addition to the first region 131. The substrate connection portion 81a or 81b is formed over the entire second region 132, but may be formed only in a part of the second region 132. The substrate connection portion 81a may be formed on the second inclined surface 22a in addition to the second region 132. The substrate connection portion 81b may be formed on the second inclined surface 22b in addition to the second region 132.

[0053] Side portions 72a and 82a are formed on outer end surface 16 of flange portion 12a. Side portions 72b and 82b are formed on outer end surface 16 of flange portion 12b. Side portion 72a is continuous with board connection portion 71a, side portion 72b is continuous with board connection portion 71b, side portion 82a is continuous with board connection portion 81a, and side portion 82b is continuous with board connection portion 81b. Fillets of solder, conductive adhesive, etc. are formed on sides 72a, 72b, 82a, and 82b.

[0054] The first terminal electrode 70a (similarly for the first terminal electrode 70b, the second terminal electrode 80a, and the second terminal electrode 80b) is configured, for example, by a laminated electrode film of a base electrode film and a plating film formed on the base electrode film. Examples of the base electrode film include a conductive paste film containing metals such as Sn, Ag, Ni, Cu, etc. or alloys thereof. Examples of the plating film include a metal such as Sn, Au, Ni, Pt, Ag, Pd, etc. or alloys thereof. The thickness of the first terminal electrode 70a is, for example, 3 to 100 μm.

[0055] As shown in FIG. 1D , the pair of the first wire 50 and the second wire 60 has multiple turns 40 spaced apart from each other along the X-axis direction. Adjacent turns 40 in the X-axis direction are spaced apart and arranged in the X-axis direction. That is, in this embodiment, the pair of the first wire 50 and the second wire 60 is wound in a so-called spaced-apart fashion. The spacing between adjacent turns 40 in the X-axis direction is not particularly limited, but may be, for example, one or more times or two or more times the diameter of the first wire 50 or the second wire 60. In the example shown in FIG. 1D , the spacing between adjacent turns in the X-axis direction is constant, but may also be different.

[0056] 1B, the first drawn-out portion 52a is drawn out from the winding core 11 toward the flange 12a. The second drawn-out portion 62a is drawn out from the winding core 11 toward the flange 12a. The first drawn-out portion 52b is drawn out from the winding core 11 toward the flange 12b. The second drawn-out portion 62b is drawn out from the winding core 11 toward the flange 12b.

[0057] The first drawn-out section 52a has a straight portion 53 and a rising portion 54. The second drawn-out section 62a has an inclined portion 65 and a rising portion 64. The first drawn-out section 52b has an inclined portion 55 and a rising portion 54. The second drawn-out section 62b has a straight portion 63 and a rising portion 64.

[0058] The straight portion 53 of the first lead portion 52a passes through (extends) the recess 20a along the X-axis direction. The straight portion 53 extends along the first inner wall surface 23a. The straight portion 53 may be in contact with the first inner wall surface 23a or may be spaced apart from the first inner wall surface 23a. The raised portion 54 of the first lead portion 52a extends along the Y-axis direction and rises from the bottom surface 200 of the recess 20a toward the first terminal electrode 70a (board connection portion 71a). The raised portion 54 extends to the end of the mounting surface 13 on the negative Y-axis direction side, although this is not particularly limited. The raised portion 54 extends along the first protruding surface 25a. The raised portion 54 may be in contact with the first protruding surface 25a or may be spaced apart from the first protruding surface 25a.

[0059] The inclined portion 65 of the second lead portion 62a passes through the recess 20a at an angle with respect to the X-axis direction. The inclined portion 65 is inclined in a direction away from the first lead portion 52a as it extends outward in the X-axis direction. The raised portion 64 of the second lead portion 62a extends along the Y-axis direction and rises from the bottom surface 200 of the recess 20a toward the second terminal electrode 80a (board connection portion 81a). The raised portion 64 extends to the end of the mounting surface 13 on the positive side of the Y-axis, although this is not particularly limited. The raised portion 64 extends along the second protruding surface 26a. The raised portion 64 may be in contact with the second protruding surface 26a or may be spaced apart from the second protruding surface 26a.

[0060] The inclined portion 55 of the first lead portion 52b passes through the recess 20b obliquely with respect to the X-axis direction. The inclined portion 55 is inclined in a direction away from the second lead portion 62b as it extends outward in the X-axis direction. The raised portion 54 of the first lead portion 52b extends along the Y-axis direction and rises from the bottom surface 200 of the recess 20b toward the first terminal electrode 70b (board connection portion 71b). The raised portion 54 extends to the end of the mounting surface 13 on the negative Y-axis direction side, although this is not particularly limited. The raised portion 54 extends along the first protruding surface 25b. The raised portion 54 may be in contact with the first protruding surface 25b or may be spaced apart from the first protruding surface 25b.

[0061] The straight portion 63 of the second lead portion 62b passes through (extends) the recess 20b along the X-axis direction. The straight portion 63 extends along the second inner wall surface 24b. The straight portion 63 may be in contact with the second inner wall surface 24b or may be spaced apart from the second inner wall surface 24b. The rising portion 64 of the second lead portion 62b extends along the Y-axis direction and rises from the bottom surface 200 of the recess 20b toward the second terminal electrode 80b (board connection portion 81b). The rising portion 64 extends to the end of the mounting surface 13 on the positive side of the Y-axis, although this is not particularly limited. The rising portion 64 extends along the second protruding surface 26b. The rising portion 64 may be in contact with the second protruding surface 26b or may be spaced apart from the second protruding surface 26b.

[0062] The rising portions 54 and 64 extend along the Y-axis direction so as to be spaced apart from each other. The rising portions 54 and 64 are located on the same straight line parallel to the Y-axis direction. However, the position of the rising portions 54 and the position of the rising portions 64 may be offset along the X-axis direction.

[0063] The first lead portion 52a is in direct or indirect contact with the core 10 and is drawn from the winding core 11 to the first terminal electrode 70a. More specifically, the straight portion 53 is in contact with the bottom surface 200 of the recess 20a, and the rising portion 54 is in contact with the first inclined surface 21a. The second lead portion 62a is in direct or indirect contact with the core 10 and is drawn from the winding core 11 to the second terminal electrode 80a. More specifically, the inclined portion 65 is in contact with the bottom surface 200 of the recess 20a, and the rising portion 64 is in contact with the second inclined surface 22a.

[0064] The first lead portion 52b is in direct or indirect contact with the core 10 and is drawn from the winding core 11 to the first terminal electrode 70b. More specifically, the inclined portion 55 is in contact with the bottom surface 200 of the recess 20b, and the rising portion 54 is in contact with the first inclined surface 21b. The second lead portion 62b is in direct or indirect contact with the core 10 and is drawn from the winding core 11 to the second terminal electrode 80b. More specifically, the straight portion 63 is in contact with the bottom surface 200 of the recess 20b, and the rising portion 64 is in contact with the second inclined surface 22b.

[0065] 1A, the first connection position 56 between the first lead portion 52a and the first terminal electrode 70a is closer to the inner end face 15 (FIG. 2) than to the outer end face 16 (FIG. 2) of the flange portion 12a. The second connection position 66 between the second lead portion 62a and the second terminal electrode 80a is closer to the inner end face 15 than to the outer end face 16 of the flange portion 12a. The first connection position 56 between the first lead portion 52b and the first terminal electrode 70b is closer to the inner end face 15 than to the outer end face 16 of the flange portion 12b. The second connection position 66 between the second lead portion 62b and the second terminal electrode 80b is closer to the inner end face 15 than to the outer end face 16 of the flange portion 12b.

[0066] However, the first connection position 56 may be located at a position equidistant from the outer end surface 16 and the inner end surface 15 in the X-axis direction, or may be closer to the outer end surface 16 than to the inner end surface 15. The second connection position 66 may be located at a position equidistant from the outer end surface 16 and the inner end surface 15 in the X-axis direction, or may be closer to the outer end surface 16 than to the inner end surface 15.

[0067] The distance in the X-axis direction between the first connection position 56 and the outer end surface 16 is at least twice the diameter of the first wire 50 or the second wire 60. In addition, the distance in the X-axis direction between the second connection position 66 and the outer end surface 16 is at least twice the diameter of the first wire 50 or the second wire 60.

[0068] The first lead portion 52a (similarly for the first lead portion 52b, the second lead portion 62a and the second lead portion 62b) is connected to the first terminal electrode 70a (substrate connection portion 71a) by, for example, laser welding, solder, conductive adhesive, thermocompression bonding, ultrasonic bonding, resistance brazing, ultraviolet curing resin bonding, etc.

[0069] The plate core 30 has a flat rectangular parallelepiped shape. The material constituting the plate core 30 is the same as the material constituting the core 10, but may be different. As shown in Fig. 1D, the plate core 30 is attached to the mounting surface 14 of the first flange portion 12a and the mounting surface 14 of the second flange portion 12b by, for example, an adhesive.

[0070] Next, a method for manufacturing the coil device 1 will be described. First, a core 10 having recesses 20a and 20b, first inclined surfaces 21a and 21b, and second inclined surfaces 22a and 22b shown in FIG. 2 is prepared. The length of the core 10 in the X-axis direction is not particularly limited, but is, for example, 0.4 mm to 6 mm. The length of the core 10 in the Y-axis direction is not particularly limited, but is, for example, 0.2 mm to 6 mm. The length of the core 10 in the Z-axis direction is not particularly limited, but is, for example, 0.2 mm to 3 mm.

[0071] These recesses and inclined surfaces are formed by cutting the flange of the core and hollowing out a portion of the flange. Next, first terminal electrode 70a and second terminal electrode 80a are formed on mounting surface 13 of flange 12a, and first terminal electrode 70b and second terminal electrode 80b are formed on mounting surface 13 of flange 12b.

[0072] 1D, the first wire 50 and the second wire 60 are wound around the outer peripheral surface 110 of the winding core 11 by bifilar winding and space winding. That is, the pair of the first wire 50 and the second wire 60 are wound around the outer peripheral surface 110 so that a gap is formed between the turns 40 adjacent to each other in the X-axis direction.

[0073] 1A and 1B, first lead portion 52a (straight portion 53) is drawn out from winding core 11 toward recess 20a along first inner wall surface 23a. Furthermore, first lead portion 52a (rising portion 54) is raised obliquely from recess 20a to first terminal electrode 70a along first inclined surface 21a and first protruding surface 25a.

[0074] The second lead portion 62a (inclined portion 65) is drawn out obliquely with respect to the X-axis direction from the winding core portion 11 toward the recessed portion 20a. The second lead portion 62a (rising portion 64) rises obliquely from the recessed portion 20a to the second terminal electrode 80a along the second inclined surface 22a and the second protruding surface 26a.

[0075] Additionally, the second lead portion 52b (inclined portion 54) is drawn out obliquely with respect to the X-axis direction from the winding core portion 11 toward the recessed portion 20b. Additionally, the first lead portion 52b (rising portion 54) is raised from the recessed portion 20b to the first terminal electrode 70b along the first inclined surface 21b and the first protruding surface 25b.

[0076] Additionally, the second lead-out portion 62b (straight portion 63) is led out from the winding core portion 11 toward the recessed portion 20b along the second inner wall surface 24b. Additionally, the second lead-out portion 62b (rising portion 64) is raised from the recessed portion 20b to the second terminal electrode 80b along the second inclined surface 22b and the second protruding surface 26b.

[0077] Next, the rising portion 54 of the first lead portion 52a is connected to the substrate connection portion 71a of the first terminal electrode 70a, for example, by thermocompression bonding. Similarly, the rising portion 64 of the second lead portion 62a is connected to the substrate connection portion 81a of the second terminal electrode 80a. Similarly, the rising portion 54 of the first lead portion 52b is connected to the substrate connection portion 71b of the first terminal electrode 70b. Similarly, the rising portion 64 of the second lead portion 62b is connected to the substrate connection portion 81b of the second terminal electrode 80b.

[0078] 1D, the plate core 30 is attached to the mounting surface 14 of the flange portion 12a and the mounting surface 14 of the flange portion 12b. For example, the plate core 30 may be adhered to the mounting surface 14 with an adhesive. In this manner, the coil device 1 can be manufactured.

[0079] As shown in FIG. 1A , in the coil device 1 of this embodiment, the flange portion 12a has a recess 20a recessed from the mounting surface 13 between the first terminal electrode 70a and the second terminal electrode 80a. Therefore, at least a portion of the path that diffuses magnetic flux toward the mounting surface 13 of the flange portion 12a is blocked by the recess 20a, making it difficult for the magnetic flux to diffuse toward the mounting surface 13. This reduces leakage magnetic flux and increases the amount of magnetic flux passing through the path that connects the winding core portion 11, the flange portion 12a, the plate core 30, and the flange portion 12b over the shortest distance. This reduces the insertion loss of the coil device 1 due to leakage magnetic flux. Furthermore, the bottom surface 200 of the recess 20a is flush with the outer circumferential surface 110 of the winding core portion 11. Therefore, no step is formed between the bottom surface 200 of the recess 20a and the outer circumferential surface 110 of the winding core portion 11, preventing magnetic flux from concentrating at the step, which is a cause of insertion loss.

[0080] 1D, the second wire 60 is wound around the winding core 11 to form a pair with the first wire 50. The pair of the first wire 50 and the second wire 60 has a plurality of turns 40 spaced apart from each other along the X-axis direction. This improves the coupling between the first wire 50 and the second wire 60, reducing leakage flux. Furthermore, the stray capacitance between adjacent turns 40 along the X-axis direction is reduced. This further reduces the insertion loss of the coil device 1 due to leakage flux.

[0081] In Fig. 3A, the graph indicated by the solid line shows the simulation results of the frequency characteristics of leakage inductance of the coil device 1 of this embodiment, and the graph indicated by the dashed line shows the simulation results of the frequency characteristics of leakage inductance of a conventional coil device. The conventional coil device differs from the coil device 1 of this embodiment in that it does not have recesses 20a and 20b. As can be seen from Fig. 3A, the coil device 1 of this embodiment has a smaller leakage inductance than the conventional coil device, at least in the frequency band of 3500 MHz or less.

[0082] 3B, the graph indicated by the solid line shows the simulation results of the frequency characteristics of insertion loss for the coil device 1 of this embodiment, and the graph indicated by the dashed line shows the simulation results of the frequency characteristics of insertion loss for a conventional coil device. The conventional coil device differs from the coil device 1 of this embodiment in that it does not have recesses 20a and 20b. As can be seen from FIG. 3B, the coil device 1 of this embodiment has a smaller insertion loss than the conventional coil device, at least in the frequency band of 4000 MHz or less.

[0083] 2, flange portion 12a has an inner end surface 15 connected to winding core portion 11 and an outer end surface 16 opposite inner end surface 15 along the X-axis direction. Recess 20a extends from inner end surface 15 to outer end surface 16 along the X-axis direction. Therefore, in a wide range between first terminal electrode 70a and second terminal electrode 80a, recess 20a blocks at least a portion of the path that diffuses magnetic flux toward mounting surface 13 of flange portion 12a. This effectively reduces leakage magnetic flux.

[0084] 1A, the first wire 50 has a first lead portion 52a drawn from the winding core 11 toward the flange 12a. The second wire 60 has a second lead portion 62a drawn from the winding core 11 toward the flange 12a. The first lead portion 52a is drawn from the winding core 11 to the first terminal electrode 70a while in contact with the core 10. The second lead portion 62a is drawn from the winding core 11 to the second terminal electrode 80a while in contact with the core 10. This makes it difficult for the first lead portion 52a and the second lead portion 62a to be wired in the air, thereby preventing breakage of the first lead portion 52a and the second lead portion 62a.

[0085] 1B, first lead portion 52a has a straight portion 53 that passes through recess 20a along the X-axis direction and a rising portion 54 that extends along the Y-axis direction and rises from bottom surface 200 of recess 20a toward first terminal electrode 70a. Second lead portion 62a has an inclined portion 65 that passes through recess 20a obliquely with respect to the X-axis direction and a rising portion 64 that extends along the Y-axis direction and rises from bottom surface 200 of recess 20a toward second terminal electrode 80a. Therefore, first lead portion 52a (straight portion 53) can be drawn out along the X-axis direction from winding core 11 to a predetermined position in recess 20a (the rising position of first lead portion 52a) in the shortest distance. Furthermore, the second drawn-out portion 62a (inclined portion 65) can be drawn out in the shortest distance from the winding core 11 to the predetermined position of the recess 20a (the rising position of the second drawn-out portion 62a) while avoiding bending of the second drawn-out portion 62a.

[0086] The flange portion 12a has a first inclined surface 21a and a second inclined surface 22a. The first inclined surface 21a is inclined from the bottom surface 200 of the recess 20a toward the mounting surface 13 on one side in the Y-axis direction. The second inclined surface 22a is inclined from the bottom surface 200 of the recess 20a toward the mounting surface 13 on the other side in the Y-axis direction. This allows the first lead portion 52a to be extended to the mounting surface 13 along the first inclined surface 21a while preventing excessive bending of the first lead portion 52a. Furthermore, the second lead portion 62a can be extended to the mounting surface 13 along the second inclined surface 22a while preventing excessive bending of the second lead portion 62a. This prevents breakage of the first lead portion 52a and the second lead portion 62a due to bending.

[0087] 2, the flange 12a has a first inner wall surface 23a and a second inner wall surface 24a. The first inner wall surface 23a rises vertically from the bottom surface 200 of the recess 20a toward the mounting surface 13 on one side in the Y-axis direction. The second inner wall surface 24a rises vertically from the bottom surface 200 of the recess 20a toward the mounting surface 13 on the other side in the Y-axis direction. In the X-axis direction, the first inner wall surface 23a is located inside the flange 12a, and the first inclined surface 21a is located outside the flange 12a. In the X-axis direction, the second inner wall surface 24a is located inside the flange 12a, and the second inclined surface 22a is located outside the flange 12a. 1B, first drawn-out portion 52a can be drawn out along first inner wall surface 23a to first inclined surface 21a, and then further drawn out along first inclined surface 21a to mounting surface 13. Alternatively, second drawn-out portion 62b can be drawn out along second inner wall surface 24b to second inclined surface 22b, and then further drawn out along second inclined surface 22b to mounting surface 13. This prevents variation in the drawn-out positions of first drawn-out portion 52a and second drawn-out portion 62b.

[0088] The flange portion 12a has an inner end surface 15 connected to the winding core portion 11 and an outer end surface 16 opposite the inner end surface 15 along the X-axis direction. As shown in FIG. 1A , a first connection position 56 between the first lead portion 52a and the first terminal electrode 70a is closer to the inner end surface 15 than the outer end surface 16. A second connection position 66 between the second lead portion 62a and the second terminal electrode 80a is closer to the inner end surface 15 than the outer end surface 16. Therefore, a connection surface between the first terminal electrode 70a and the mounting board can be secured between the first connection position 56 and the outer end surface 16. A connection surface between the second terminal electrode 80a and the mounting board can be secured between the second connection position 66 and the outer end surface 16. These connection surfaces have good adhesive properties for solder, conductive adhesive, or the like, thereby increasing the mounting strength between the coil device 1 and the mounting board.

[0089] Second embodiment 4A has the same configuration as the coil device 1 of the first embodiment, except for the following points. The same reference numerals are used to designate parts that overlap with the coil device 1 of the first embodiment, and detailed descriptions thereof will be omitted.

[0090] The coil device 1A has a core 10A. The core 10A has flanges 12aA and 12bA. The flange 12aA differs from the flange 12a of the first embodiment in that it does not have the first inclined surface 21a or the second inclined surface 22a. The flange 12bA differs from the flange 12b of the first embodiment in that it does not have the first inclined surface 21b or the second inclined surface 22b.

[0091] The first inner wall surface 23a extends continuously along the X-axis direction from the inner end surface 15 to the outer end surface 16 of the flange portion 12aA. The second inner wall surface 24a extends continuously along the X-axis direction from the inner end surface 15 to the outer end surface 16 of the flange portion 12aA.

[0092] The first inner wall surface 23b extends continuously along the X-axis direction from the inner end surface 15 to the outer end surface 16 of the flange portion 12bA. The second inner wall surface 24b extends continuously along the X-axis direction from the inner end surface 15 to the outer end surface 16 of the flange portion 12bA.

[0093] The rising portion 54 of the first lead-out portion 52a rises from the bottom surface 200 of the recess 20a while making contact with the first inner wall surface 23a. The rising portion 54 rises perpendicular to the bottom surface 200, along the first inner wall surface 23a. The rising portion 54 is also drawn out along the mounting surface 13 (first region 131) and connected to the first terminal electrode 70a (board connection portion 71a). The rising portion 54 extends parallel to the Z axis, but may be inclined in the XZ plane with respect to the Z axis.

[0094] The rising portion 64 of the second lead-out portion 62a rises from the bottom surface 200 of the recess 20a while making contact with the second inner wall surface 24a. The rising portion 64 rises perpendicular to the bottom surface 200, along the second inner wall surface 24a. The rising portion 64 is also drawn out along the mounting surface 13 (second region 132) and connected to the second terminal electrode 80a (substrate connection portion 81a). The rising portion 64 extends parallel to the Z axis, but may be inclined in the XZ plane with respect to the Z axis.

[0095] The rising portion 54 of the first lead-out portion 52b rises from the bottom surface 200 of the recess 20b while making contact with the first inner wall surface 23b. The rising portion 54 rises perpendicular to the bottom surface 200, along the first inner wall surface 23b. The rising portion 54 is also drawn out along the mounting surface 13 (first region 131) and connected to the first terminal electrode 70b (board connection portion 71b). The rising portion 54 extends parallel to the Z axis, but may be inclined in the XZ plane with respect to the Z axis.

[0096] The rising portion 64 of the second lead-out portion 62b rises from the bottom surface 200 of the recess 20b while making contact with the second inner wall surface 24b. The rising portion 64 rises perpendicular to the bottom surface 200, along the second inner wall surface 24b. The rising portion 64 is also drawn out along the mounting surface 13 (second region 132) and connected to the second terminal electrode 80b (substrate connection portion 81b). The rising portion 64 extends parallel to the Z axis, but may be inclined in the XZ plane with respect to the Z axis.

[0097] 4B, the rising portions 54 and 64 extend along the Y-axis direction so as to be spaced apart from each other. The rising portions 54 and 64 are located on the same straight line parallel to the Y-axis direction. However, the positions of the rising portions 54 and 64 may be offset from each other along the X-axis direction.

[0098] In this embodiment, the same effects as in the first embodiment can be obtained. In addition, in this embodiment, the flange portion 12a does not have the first inclined surface 21a and the second inclined surface 22a (FIG. 2), and a portion of the mounting surface 13 is not cut by the first inclined surface 21a and the second inclined surface 22a. Therefore, the area of ​​the mounting surface 13 (the first region 131 and the second region 132) increases accordingly, and the areas of the first terminal electrode 70a and the second terminal electrode 80a also increase. This can increase the mounting strength between the coil device 1 and the mounting board (not shown).

[0099] Third embodiment The coil device 1B of the third embodiment shown in Fig. 5 has the same configuration as the coil device 1 of the first embodiment, except for the following points. The same reference numerals are used to designate parts that overlap with the coil device 1 of the first embodiment, and detailed descriptions thereof will be omitted.

[0100] 5, in this embodiment, the first lead portion 52a has a straight portion 53 that passes through the recess 20a along the X-axis direction. The first lead portion 52a also has a rising portion 54 that extends along the Y-axis direction and rises from the bottom surface 200 of the recess 20a toward the mounting surface 13 (first region 131). In the example shown in FIG. 5, the straight portion 53 is perpendicular to the rising portion 54.

[0101] The second lead-out portion 62a has a straight portion 63 that passes through the recess 20a along the X-axis direction. The second lead-out portion 62a also has a rising portion 64 that extends along the Y-axis direction and rises from the bottom surface 200 of the recess 20a toward the mounting surface 13 (second region 132). In the example shown in FIG. 5, the straight portion 63 is perpendicular to the rising portion 64.

[0102] The first lead-out portion 52b has a straight portion 53 that passes through the recess 20b along the X-axis direction. The first lead-out portion 52b also has a rising portion 54 that extends along the Y-axis direction and rises from the bottom surface 200 of the recess 20b toward the mounting surface 13 (first region 131). In the example shown in FIG. 5, the straight portion 53 is perpendicular to the rising portion 54.

[0103] The second lead-out portion 62b has a straight portion 63 that passes through the recess 20b along the X-axis direction. The second lead-out portion 62b also has a rising portion 64 that extends along the Y-axis direction and rises from the bottom surface 200 of the recess 20b toward the mounting surface 13 (second region 132). In the example shown in FIG. 5, the straight portion 63 is perpendicular to the rising portion 64.

[0104] 5, the straight portions 53 and 63 extend parallel to each other along the X-axis direction. The distance between the straight portions 53 and 63 in the Y-axis direction is not particularly limited, but is equal to or greater than the diameter of the first wire 50 or the second wire 60. However, the straight portions 53 and 63 may be in contact with each other.

[0105] The present embodiment also achieves the same effects as the first embodiment. Additionally, as described above, in the present embodiment, both the first lead portion 52a and the second lead portion 62a have straight portions (straight portions 53 and 63). Therefore, the first lead portion 52a and the second lead portion 62a are extended from the winding core portion 11 to the mounting surface 13 so as to be symmetrical with respect to the X-axis direction. This allows the lengths of the first lead portion 52a and the second lead portion 62a to be similar, thereby reducing the insertion loss of the coil device 1. Furthermore, the first raised portion 54 and the second raised portion 64 are extended from the bottom surface 200 of the recess 20a to the mounting surface 13 parallel to the outer end surface 16 of the flange portion 12a so as not to extend toward the outer end surface 16. Therefore, the first lead portion 52a can be connected to the first terminal electrode 70a (substrate connection portion 71a) at a position away from the outer end surface 16, ensuring a sufficient mounting area for the first terminal electrode 70a. Furthermore, the second lead portion 62a can be connected to the second terminal electrode 80a (substrate connection portion 81a) at a position away from the outer end surface 16, making it possible to ensure a mounting area for the second terminal electrode 80a.

[0106] Fourth embodiment The coil device 1C of the fourth embodiment shown in Fig. 6 has the same configuration as the coil device 1 of the second embodiment, except for the following points. The same reference numerals are used to designate parts that overlap with the coil device 1 of the first embodiment, and detailed descriptions thereof will be omitted.

[0107] 6, in the flange portion 12aA, the first region 131 of the mounting surface 13 has an exposed portion 133 located between the first terminal electrode 70a (substrate connecting portion 71a) and the recess 20a. The second region 132 of the mounting surface 13 has an exposed portion 133 located between the second terminal electrode 80a (substrate connecting portion 81a) and the recess 20a. In the exposed portion 133 of the first region 131, the mounting surface 13 is not covered by the first terminal electrode 70a and is exposed to the outside. In the exposed portion 133 of the second region 132, the mounting surface 13 is not covered by the second terminal electrode 80a and is exposed to the outside.

[0108] In addition, in the flange portion 12bA, the first region 131 of the mounting surface 13 has an exposed portion 133 located between the first terminal electrode 70b (substrate connecting portion 71b) and the recess 20b. In addition, the second region 132 of the mounting surface 13 has an exposed portion 133 located between the second terminal electrode 80b (substrate connecting portion 81b) and the recess 20b. In the exposed portion 133 of the first region 131, the mounting surface 13 is not covered by the first terminal electrode 70b and is exposed to the outside. In the exposed portion 133 of the second region 132, the mounting surface 13 is not covered by the second terminal electrode 80b and is exposed to the outside.

[0109] The exposed portion 133 extends along the X-axis from the inner end surface 15 to the outer end surface 16. The width of the exposed portion 133 in the Y-axis direction is narrower than the width of the first terminal electrode 70a (substrate connecting portion 71a) in the Y-axis direction. The width of the exposed portion 133 in the Y-axis direction is not particularly limited, but is less than 1 / 2 or 1 / 3 of the width of the first terminal electrode 70a (substrate connecting portion 71a) in the Y-axis direction. The width of the exposed portion 133 in the Y-axis direction is constant along the X-axis direction, but may vary.

[0110] In this embodiment, the same effects as those of the second embodiment can be obtained. Additionally, in this embodiment, the first region 131 has an exposed portion 133 located between the first terminal electrode 70a and the recess 20a. The second region 132 has an exposed portion 133 located between the second terminal electrode 80a and the recess 20a. The mounting surface 13 is exposed at these exposed portions 133. Because the first terminal electrode 70a is not formed at the exposed portion 133 of the first region 131, the stray capacitance between the first wire 50 (first lead portion 52a) and the first terminal electrode 70a is reduced, thereby reducing the insertion loss of the coil device 1C. Furthermore, because the second terminal electrode 80a is not formed at the exposed portion 133 of the second region 132, the stray capacitance between the second wire 60 (second lead portion 62a) and the second terminal electrode 80a is reduced, thereby reducing the insertion loss of the coil device 1C.

[0111] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0112] As shown in Fig. 7, the technology of the third embodiment may be applied to the second embodiment. That is, both the first drawer section 52a and the second drawer section 62a may have straight portions (straight portions 53 and 63). Also, both the first drawer section 52b and the second drawer section 62b may have straight portions (straight portions 53 and 63).

[0113] In each of the above embodiments, the first terminal electrode 70a (the same applies to the first terminal electrode 70b, the second terminal electrode 80a, and the second terminal electrode 80b) may be formed of a terminal fitting obtained by bending and / or cutting a metal plate.

[0114] In each of the above embodiments, first flange 12a may be formed with only one of first inclined surface 21a and second inclined surface 22a, and first flange 12b may be formed with only one of first inclined surface 21b and second inclined surface 22b.

[0115] In the second to fourth embodiments shown in FIGS. 4B, 5, 6, and 7, the connection position between the first lead portion 52a and the first terminal electrode 70a is equidistant from the outer end surface 16 and the inner end surface 15, but may be closer to the inner end surface 15 than to the outer end surface 16. The connection position between the second lead portion 62a and the second terminal electrode 80a is equidistant from the outer end surface 16 and the inner end surface 15, but may be closer to the inner end surface 15 than to the outer end surface 16. The connection position between the first lead portion 52b and the first terminal electrode 70b is equidistant from the outer end surface 16 and the inner end surface 15, but may be closer to the inner end surface 15 than to the outer end surface 16. Furthermore, the connection position between the second lead portion 62b and the second terminal electrode 80b is located at a position equidistant from the outer end face 16 and the inner end face 15, but may be closer to the inner end face 15 than to the outer end face 16. [Explanation of symbols]

[0116] 1, 1A to 1C... Coil device 10,10A...Core 11...Core 110...Outer surface 111…Top surface 12a,12b,12aA,12bA…Trim part 13...Mounting surface 131...First area 132…Second area 133...Exposed part 14...Mounting surface 15...Inner end surface 16...Outer end surface 17…First side 18…Second side 20a, 20b...recessed portion 200...Bottom 21a, 21b...first slope 22a, 22b…Second slope 23a, 23b…First inner wall surface 24a, 24b…Second inner wall surface 25a, 25b...first protruding surface 26a, 26b…Second protruding surface 30...Plate core 40...Turn 50...First wire 51...winding section 52a, 52b...Drawer part 53...Straight section 54...Rising section 55…Slope part 56...Connection position 60...Second wire 61...winding section 62a, 62b…Drawer part 63...Straight section 64...Rising section 65…Slope part 66...Connection position 70a,70b,80a,80b…Terminal electrode 71a, 71b, 81a, 81b...Board connection parts 72a, 72b, 82a, 82b...side

Claims

1. a core having a winding core portion and a flange portion formed at an axial end of the winding core portion; a plate-shaped core attached to the core; a first wire wound around the winding core; a second wire wound around the winding core to form a pair with the first wire; a first terminal electrode provided on at least the mounting surface of the flange; a second terminal electrode provided at least on the mounting surface and spaced apart from the first terminal electrode; the flange portion has a recess recessed from the mounting surface between the first terminal electrode and the second terminal electrode, a bottom surface of the recessed portion is flush with an outer peripheral surface of the winding core portion, A coil device in which the pair of first and second wires have a plurality of turns spaced apart from each other along the axial direction.

2. the flange portion has an inner end surface connected to the winding core portion and an outer end surface opposite to the inner end surface along the axial direction, The coil device according to claim 1 , wherein the recess extends from the inner end surface to the outer end surface along the axial direction.

3. the first wire has a first drawn-out portion drawn out from the winding core portion toward the flange portion, the second wire has a second drawn-out portion drawn out from the winding core portion toward the flange portion, the first lead portion is drawn from the winding core portion to the first terminal electrode while being in contact with the core, The coil device according to claim 1 or 2, wherein the second lead portion is led from the winding core portion to the second terminal electrode while being in contact with the core.

4. the first lead-out portion has a first straight portion that passes through the recess along the axial direction, and a first rising portion that extends along a direction perpendicular to the axial direction in a plan view and rises from a bottom surface of the recess toward the mounting surface, 4. The coil device according to claim 3, wherein the second lead-out portion has a second straight portion that passes through the recess along the axial direction, and a second rising portion that extends along a direction perpendicular to the axial direction in a plan view and rises from a bottom surface of the recess toward the mounting surface.

5. the first lead portion has a straight portion that passes through the recess along the axial direction, and a first rising portion that extends along a direction perpendicular to the axial direction in a plan view and rises from a bottom surface of the recess toward the first terminal electrode, 4. The coil device according to claim 3, wherein the second lead-out portion has an inclined portion that passes through the recess obliquely with respect to the axial direction, and a second raised portion that extends along a direction perpendicular to the axial direction in a plan view and rises from a bottom surface of the recess toward the second terminal electrode.

6. The flange portion has a first inclined surface and a second inclined surface, the first inclined surface is inclined from a bottom surface of the recess toward the mounting surface on one side in a direction perpendicular to the axial direction in a plan view, The coil device according to claim 1 , wherein the second inclined surface is inclined from a bottom surface of the recess toward the mounting surface on the other side in a direction perpendicular to the axial direction in a plan view.

7. The flange portion has a first inner wall surface and a second inner wall surface, the first inner wall surface rises vertically from a bottom surface of the recess toward the mounting surface on one side in a direction perpendicular to the axial direction in a plan view, the second inner wall surface rises vertically from a bottom surface of the recess toward the mounting surface on the other side in a direction perpendicular to the axial direction in a plan view, In the axial direction, the first inner wall surface is located inside the flange portion, and the first inclined surface is located outside the flange portion, The coil device according to claim 6 , wherein the second inner wall surface is located inside the flange portion and the second inclined surface is located outside the flange portion in the axial direction.

8. the flange portion has an inner end surface connected to the winding core portion and an outer end surface opposite to the inner end surface along the axial direction, a first connection position between the first lead portion and the first terminal electrode is closer to the inner end surface than to the outer end surface; The coil device according to claim 1 or 2, wherein a second connection position between the second lead portion and the second terminal electrode is closer to the inner end surface than to the outer end surface.

9. the mounting surface includes a first region in which the first terminal electrodes are provided and a second region in which the second terminal electrodes are provided; The recess is located between the first region and the second region, the first region has a first exposed portion located between the first terminal electrode and the recess, the second region has a second exposed portion located between the second terminal electrode and the recess, The coil device according to claim 1 or 2, wherein the mounting surface is exposed at the first exposed portion and the second exposed portion.

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