Coil component

Abstract

To provide a coil component which can be improved in magnetic characteristics.SOLUTION: A coil component comprises: a core having a winding core part extended in an axial direction and a first flange part and a second flange part provided at both ends of the winding core part in the axial direction; a coil wound around the winding core part; and a top plate provided in such a manner that it straddles the first flange part and the second flange part. The first flange part has a first facing surface facing the top plate. The top plate has a second facing surface facing the first flange part. In a cross section orthogonal to the axial direction and intersecting the first flange part, a convex part convex toward the top plate side is provided on the first facing surface, and a concave part concave toward an opposite side to the first flange part side is provided on the second facing surface. When the height of the convex part is denoted as A (A>0) and a depth of the concave part is denoted as B (B<0), a sum A+B of the height of the convex part and the depth of the concave part is -6 μm or more and 19 μm or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventional coil components include those disclosed in Patent Documents 1 and 2.

[0003] The coil component disclosed in Patent Document 1 includes a drum core having flanges provided on both ends of a winding core, and a plate-like core having a lower surface facing the upper surfaces of the flanges. The lower surface of the plate-like core is flat. The upper surface of each flange of the drum core is convex.

[0004] The coil component disclosed in Patent Document 2 includes a core having flanges provided at both ends of a winding core, and a top plate provided so as to straddle each flange. The bottom surface of the top plate is concave. The top surface of each flange faces the bottom surface of the top plate, which has a convex top surface.

[0005] In the coil component disclosed in Patent Document 1, the gap between the upper surface of each flange and the lower surface of the plate-like core becomes smaller as the distance approaches the center of the drum core.In the coil component disclosed in Patent Document 2, the gap between the upper surface of each flange and the lower surface of the top plate becomes smaller as the distance approaches the center of the core. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-99587 [Patent Document 2] Japanese Patent Publication No. 2024-7882 Summary of the Invention [Problem to be solved by the invention]

[0007] The coil components disclosed in Patent Documents 1 and 2 have at least one of the opposing upper and lower surfaces that is not flat, resulting in wide and narrow gaps between the upper and lower surfaces. This wide gap may reduce the magnetic properties of the coil components. The coil component disclosed in Patent Document 2, which has a convex upper surface, can reduce the gap compared to the coil component disclosed in Patent Document 1, which has a flat upper surface. However, even the coil component disclosed in Patent Document 2 leaves room for further improvement in magnetic properties.

[0008] An object of the present disclosure is to provide a coil component that can improve magnetic properties. [Means for solving the problem]

[0009] A coil component according to one aspect of the present invention comprises: a core having a winding core portion extending in an axial direction and a first flange portion and a second flange portion provided at both ends of the winding core portion in the axial direction; a coil wound around the winding core; a top plate provided so as to straddle the first flange portion and the second flange portion, the first flange portion has a first opposing surface that faces the top plate, the top plate has a second opposing surface that faces the first flange portion, In a cross section perpendicular to the axial direction and intersecting with the first flange portion, one of the first opposing surface and the second opposing surface is provided with a convex portion having a convex shape that is convex toward the other side of the first opposing surface and the second opposing surface, a recessed portion having a recessed shape that is recessed on the opposite side to one side of the first opposing surface and the second opposing surface is provided on the other of the second opposing surface and the second opposing surface, When the height of the convex portion is A (A>0) and the depth of the concave portion is B (B<0), the sum of the height of the convex portion and the depth of the concave portion, A+B, is greater than or equal to -6 μm and less than or equal to 19 μm. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a coil component that can improve magnetic properties. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing a first embodiment of a coil component as viewed from below. FIG. [Figure 2] FIG. 10 is a view of the coil component as seen from the L direction. [Figure 3] This is a view of the top plate from the bottom side. [Figure 4] FIG. 2 is a view of the core as seen from above the first flange and the second flange. [Figure 5] FIG. 10 is a view of the coil component as seen from the L direction. [Figure 6] FIG. 10 is a view of the coil component as seen from the L direction. [Figure 7] FIG. 2 is a cross-sectional view of FIG. 1 . [Figure 8] 10 is a cross-sectional view illustrating the circle of curvature of the recess of the top plate and the circle of curvature of the protrusion of the first flange. FIG. [Figure 9A] 10A to 10C are diagrams illustrating a method for forming a core molded body. [Figure 9B] 10A to 10C are diagrams illustrating a method for forming a core molded body. [Figure 9C] 10A to 10C are diagrams illustrating a method for forming a core molded body. [Figure 9D] 10A to 10C are diagrams illustrating a method for forming a core molded body. [Figure 9E] 10A to 10C are diagrams illustrating a method for forming a core molded body. [Figure 9F] 10A to 10C are diagrams illustrating a method for forming a core molded body. [Figure 10A] 10A to 10C are diagrams for explaining a method for forming a top plate molding body. [Figure 10B] 10A to 10C are diagrams for explaining a method for forming a top plate molding body. [Figure 10C] 10A to 10C are diagrams for explaining a method for forming a top plate molding body. [Figure 11] FIG. 4 is a cross-sectional view showing a second embodiment of the coil component. [Figure 12]10 is a graph showing the rate of decrease in inductance relative to the sum of the height of the convex portion and the depth of the concave portion. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a coil component and a method for manufacturing the coil component according to one aspect of the present disclosure will be described in detail with reference to the illustrated embodiments. Note that the drawings include some schematic views and may not reflect actual dimensions or proportions.

[0013] [First embodiment] (Overall composition) Fig. 1 is a perspective view from below showing a first embodiment of a coil component. As shown in Fig. 1, the coil component 1 includes a core 10, a first wire 21 and a second wire 22 wound around the core 10, a first terminal electrode 31, a second terminal electrode 32, a third terminal electrode 33, and a fourth terminal electrode 34 provided on the core 10 and electrically connected to the first wire 21 and the second wire 22, and a top plate 15 attached to the core 10. The first wire 21 and the second wire 22 correspond to the "coil" set forth in the claims.

[0014] The core 10 has a winding core portion 13 extending in the direction of the axis AX, and a first flange portion 11 and a second flange portion 12 provided on both ends in the direction of the axis AX of the winding core portion 13. Specifically, the core 10 has the winding core portion 13 that has a shape extending in the direction of the axis AX and around which the first wire 21 and the second wire 22 are wound, the first flange portion 11 that is provided at a first end in the direction of the axis AX of the winding core portion 13 and protrudes in a direction perpendicular to the direction of the axis AX, and the second flange portion 12 that is provided at a second end in the direction of the axis AX of the winding core portion 13 and protrudes in a direction perpendicular to the direction of the axis AX.

[0015] The shape of the winding core 13 is not particularly limited, but in this embodiment, the cross section of the winding core 13 perpendicular to the axis AX is rectangular. The cross section may be another polygonal shape such as a hexagon, a circle, an ellipse, or an appropriate combination of these. The material of the core 10 is preferably a magnetic material such as a sintered ferrite or a molded body of a resin containing magnetic powder, but may also be a non-magnetic material such as alumina or resin.

[0016] In the following description, the bottom surface of core 10 is referred to as the surface mounted on a mounting board, and the surface of core 10 opposite the bottom surface is referred to as the top surface of core 10. The axial direction AX of winding core portion 13 is referred to as the L direction, the direction perpendicular to the L direction on the bottom surface of core 10 is referred to as the W direction, and the direction in which the bottom and top surfaces of core 10 face each other is referred to as the T direction. The T direction is perpendicular to the L and W directions. The positive direction of the T direction is referred to as the upward direction, and the negative direction of the T direction is referred to as the downward direction. In other words, the bottom surface of core 10 corresponds to the downward vertical direction, and the top surface of core 10 corresponds to the upward vertical direction. The L direction is also referred to as the length direction of core 10, the W direction is referred to as the width direction of core 10, and the T direction is referred to as the height direction of core 10. The W direction corresponds to "a direction perpendicular to the axial direction and parallel to the top surface of the top plate" as defined in the claims.

[0017] The first flange portion 11 has an inner end surface 111 facing the winding core portion 13, an outer end surface 112 facing the opposite side to the inner end surface 111, a bottom surface 113 connecting the inner end surface 111 and the outer end surface 112 and facing the mounting board side during mounting, an upper surface 114 facing the opposite side to the lower surface 113, and two side surfaces 115 connecting the inner end surface 111 and the outer end surface 112 and connecting the lower surface 113 and the upper surface 114.

[0018] The second flange portion 12 has an inner end surface 121 facing the winding core portion 13, an outer end surface 122 facing the opposite side to the inner end surface 121, a bottom surface 123 connecting the inner end surface 121 and the outer end surface 122 and facing the mounting board side during mounting, an upper surface 124 facing the opposite side to the lower surface 123, and two side surfaces 125 connecting the inner end surface 121 and the outer end surface 122 and connecting the lower surface 123 and the upper surface 124. The lower surface 123 corresponds to the "opposite surface" described in the claims.

[0019] The top plate 15 is fixed so as to straddle the pair of first flange portion 11 and second flange portion 12. The top plate 15 has a bottom surface 151 facing the core 10 and a top surface 152 facing the opposite side of the bottom surface 151. The top plate 15 is arranged so that the top surface 152 is parallel to the WL plane. The shape of the top plate 15 when viewed from the T direction is not particularly limited, but in this embodiment, it is rectangular with long sides parallel to the L direction and short sides parallel to the W direction. The top surface 152 corresponds to the "top surface opposite the second opposing surface" described in the claims. The bottom surface 151 corresponds to the "bottom surface opposite to the top surface and including the second opposing surface" described in the claims.

[0020] The top plate 15 is attached to the upper surface 114 of the first flange 11 and the upper surface 124 of the second flange 12 with an adhesive 51. That is, the adhesive 51 fills the gap formed by the protrusions P and recesses C described below. The adhesive 51 is preferably a thermosetting epoxy resin. To improve thermal shock resistance, the adhesive 51 preferably contains an inorganic filler such as silica filler. Examples of methods for applying the adhesive 51 include the following: When applying the adhesive 51 only to the core 10, the adhesive 51 may be dipped into the upper surface 114 of the first flange 11 and the upper surface 124 of the second flange 12. When applying the adhesive 51 only to the top plate 15, the adhesive 51 may be applied to the top plate 15 using a dispenser, or printed on the top plate 15 using a printer. The adhesive 51 preferably contains magnetic powder. This allows the coil characteristics to be improved compared to when the adhesive 51 does not contain magnetic powder.

[0021] The material of the top plate 15 is, for example, the same as that of the core 10. Since both the core 10 and the top plate 15 are magnetic, they form a closed magnetic circuit, improving the efficiency of obtaining the inductance value. Therefore, the magnetic efficiency is increased, and the desired inductance value can be obtained with a smaller number of wires.

[0022] The bottom surface 151 of the top plate 15 preferably has a notch (resin reservoir) 15n at least at one of both ends in the W direction. This allows the adhesive 51 to be guided and stored in the notch 15n when bonding the core 10 and the top plate 15 together using the adhesive 51. Therefore, even if an excessive amount of adhesive 51 is used, the adhesive 51 can be prevented from spilling out of the coil component 1. In this embodiment, the notch 15n is provided along the entire periphery of the bottom surface 151 of the top plate 15. In other words, the notch 15n is provided along the entire ridge between the bottom surface 151 and the side surface of the top plate 15. The notch 15n may be provided in a part of the periphery of the bottom surface 151 of the top plate 15, or may not be provided on the top plate 15 at all.

[0023] The shape of the first flange 11 is not particularly limited except for the shape of the upper surface 114. In this embodiment, the first flange 11 has two legs on the lower surface 113 side, one of which is provided with a first terminal electrode 31, and the other is provided with a second terminal electrode 32. Similarly, the shape of the second flange 12 is not particularly limited except for the shape of the upper surface 124. In this embodiment, the second flange 12 has two legs on the lower surface 123 side, one of which is provided with the first terminal electrode 31 and the other is provided with a third terminal electrode 33, and the other is provided with the second terminal electrode 32 and the fourth terminal electrode 34. As shown in FIG. 1 , the lower surface 113 and the lower surface 123 each refer to the area extending from the bottom surface of the foot portion through the side surface of the crotch portion between the foot portions and including the bottom surface of the crotch portion.

[0024] The conductive material of the first to fourth terminal electrodes 31 to 34 is not particularly limited, but preferably contains a highly conductive metal such as Ag or Cu. The first to fourth terminal electrodes 31 to 34 can be formed, for example, by applying an Ag paste containing Ag, Si, and resin to the underside 113 of the first flange 11 and the underside 123 of the second flange 12 by a dipping method, followed by baking to form base electrodes. The first to fourth terminal electrodes 31 to 34 can then be formed by plating a thin film of Cu / Ni / Sn or the like. The first to fourth terminal electrodes 31 to 34 may also be formed by attaching a metal plate to the underside 113 and outer end surface 112 of the first flange 11 and the underside 123 and outer end surface 122 of the second flange 12 with an adhesive.

[0025] The first wire 21 and the second wire 22 are preferably insulating coated conductors, which are conductors made of a highly conductive metal such as copper, silver, or gold covered with a coating made of a resin such as polyurethane or polyamideimide. The wire diameter of each of the first wire 21 and the second wire 22 is preferably 20 μm or more and 50 μm or less. One end of the first wire 21 is electrically connected to the first terminal electrode 31, and the other end is electrically connected to the third terminal electrode 33. One end of the second wire 22 is electrically connected to the second terminal electrode 32, and the other end is electrically connected to the fourth terminal electrode 34. The first wire 21 and the second wire 22 are connected to the first to fourth terminal electrodes 31 to 34 by, for example, thermocompression bonding, brazing, welding, or the like.

[0026] The first wire 21 and the second wire 22 are wound in the same direction around the winding core 13. As a result, in the coil device 1, when an opposite-phase signal, such as a differential signal, is input to the first wire 21 and the second wire 22, the magnetic fluxes generated by the first wire 21 and the second wire 22 cancel each other out, weakening their function as inductors and allowing the signal to pass. On the other hand, when an in-phase signal, such as external noise, is input to the first wire 21 and the second wire 22, the magnetic fluxes generated by the first wire 21 and the second wire 22 reinforce each other, strengthening their function as inductors and blocking the passage of the noise. Therefore, the coil device 1 functions as a common-mode choke coil that reduces the passage loss of differential-mode signals, such as differential signals, while attenuating common-mode signals, such as external noise.

[0027] When coil component 1 is mounted on a mounting board, lower surface 113 of first flange portion 11 and lower surface 123 of second flange portion 12 face the mounting board. At this time, the axis AX direction of winding core portion 13 and the main surface of the mounting board are parallel. In other words, coil component 1 is a horizontally wound type in which the winding axes of first wire 21 and second wire 22 are parallel to the mounting board.

[0028] (Detailed configuration of the bottom surface of the top plate and the top surfaces of the first and second flanges) Next, the detailed configuration of the bottom surface 151 of the top plate 15 and the top surfaces 114, 124 of the first and second flange portions 11, 12 will be described. Fig. 2 is a view of the coil device 1 seen from the L direction. Fig. 3 is a view of the top plate 15 seen from the bottom surface 151 side. Fig. 4 is a view of the core 10 seen from the top surfaces 114, 124 sides of the first flange portion 11 and the second flange portion 12.

[0029] 2, 3, and 4, the first flange 11 and the top plate 15 each have opposing surfaces that face each other. Specifically, the top surface 114 of the first flange 11 has a first opposing surface 11f that faces the top plate 15. The first opposing surface 11f is a portion of the top surface 114 of the first flange 11 that overlaps with the top plate 15 when viewed from the T direction. In this embodiment, the first opposing surface 11f is the entire top surface 114 of the first flange 11.

[0030] The bottom surface 151 of the top plate 15 has a second opposing surface 15f1 that faces the first flange portion 11. The second opposing surface 15f1 is a portion of the bottom surface 151 of the top plate 15 that overlaps with the first flange portion 11 when viewed from the T direction. In this embodiment, the second opposing surface 15f1 is an end portion of the bottom surface 151 of the top plate 15 on the first flange portion 11 side.

[0031] The first opposing surface 11f on the first flange 11 side is provided with a convex portion P having a convex shape that convex toward the top plate 15 side (in other words, toward the second opposing surface 15f1 side) in a cross section perpendicular to the axis AX direction and intersecting with the first flange 11. The convex shape of the convex portion P is a convex curved surface that is an arc shape that convex toward the top plate 15 side when viewed from the axis AX direction. In this embodiment, the convex portion P is provided on the entire upper surface 114 of the first flange 11. In other words, the entire upper surface 114 of the first flange 11 is a convex curved surface that is an arc shape that convex toward the top plate 15 side when viewed from the axis AX direction. However, the present invention is not limited to this, and the convex portion P may be a convex curved surface that is not an arc shape. The convex portion P may also be provided on a part of the upper surface 114 of the first flange 11. For example, both ends of the upper surface 114 of the first flange portion 11 in the W direction may be flat surfaces, and the portion other than the both ends may be convexly curved.

[0032] The protrusion P has a top portion P1 when viewed from the axis AX direction. The top portion P1 is the uppermost portion of the protrusion P. In this embodiment, the top portion P1 extends in the L direction when viewed from the T direction. That is, the protrusion P has the same shape in any cross section perpendicular to the axis AX direction. However, this is not limited to this, and the protrusion P may have different shapes depending on the cross section perpendicular to the axis AX direction. Note that in FIG. 4, for convenience, the position where the protrusion P exists is shaded. Also, the top portion P1 extends in the L direction. Therefore, the top portion P1 extends in the WL plane and is therefore configured to be parallel to the lower surface 123 extending in the L direction. In other words, the top portion P1 is configured substantially parallel to the lower surface 123. The top portion P1 corresponds to a "flat portion" described in the claims. Note that the top portion P1 is not limited to a linear shape extending in the L direction as shown in FIG. 4, but may also be a planar shape extending in the WL plane.

[0033] The second opposing surface 15f1 on the top plate 15 side is provided with a recess C having a concave shape corresponding to the convex shape of the convex portion P of the first flange portion 11. The concave shape corresponding to the convex shape of the convex portion P refers to a concave shape in which the entire inner surface of the recess C comes into contact with the surface of the convex portion P when the recess C and the convex portion P are brought closer in the T direction, or a concave shape in which the inner surface shape of the recess C follows the surface shape of the convex portion P, and in which, when the recess C and the convex portion P are brought closer in the T direction, a part of the inner surface of the recess C comes into contact with a part of the surface of the convex portion P and another part of the inner surface of the recess C is separated from the surface of the convex portion P by a small distance. The small distance is, for example, more than 0 μm and not more than 10 μm, and more specifically, not less than 1 μm and not more than 5 μm.

[0034] In this embodiment, the concave shape of the recess C is a concave curved surface that is concave inward of the top plate 15 (in other words, the side opposite to the first opposing surface 11f) and has an arc shape when viewed from the axis AX direction. The second opposing surface 15f1 has notches 15n at both ends in the W direction and at the end on the first flange portion 11 side in the L direction, and the recess C is provided over the entire portion other than the notches 15n. In other words, the entire portion of the second opposing surface 15f1 other than the notches 15n is a concave curved surface that is concave inward of the top plate 15 when viewed from the axis AX direction. However, this is not limited thereto, and the recess C may be a concave curved surface that is not arc-shaped. Furthermore, the recess C may be provided in a part of the second opposing surface 15f1 other than the notches 15n. If the notches 15n are not provided in the top plate 15, the recess C may be provided over the entire second opposing surface 15f1.

[0035] The inner surface of the recess C has a top portion C1 when viewed from the direction of the axis AX. The top portion C1 is the uppermost portion of the inner surface of the recess C. In this embodiment, the top portion C1 extends in the direction L when viewed from the direction T. That is, the recess C has the same shape in any cross section perpendicular to the direction of the axis AX. However, this is not limited to this, and the recess C may have different shapes depending on the cross section perpendicular to the direction of the axis AX. Note that in FIG. 3, the position where the recess C exists is shaded for convenience.

[0036] In Figure 2, the height of the convex portion P is indicated by A. Here, height is the length in the T direction. Furthermore, height A is indicated by a positive value, i.e., A > 0. Therefore, the higher the height of the convex portion P, the larger the value of height A. Also, in Figure 2, the depth of the concave portion C is indicated by B. Here, depth is the length in the T direction. Furthermore, depth B is indicated by a negative value, i.e., B < 0. Therefore, the deeper the depth of the concave portion C, the smaller the value of depth B. In other words, the deeper the depth of the concave portion C, the larger the absolute value of depth B.

[0037] In this embodiment, when the height of the convex portion P is A (A>0) and the depth of the concave portion C is B (B<0), the sum A+B of the height A of the convex portion P and the depth B of the concave portion C is -6 μm or more and 19 μm or less. When the magnitude (in other words, the absolute value) of the height A of the convex portion P is greater than the magnitude of the depth B of the concave portion C, the difference between the height A and the depth B is a maximum of 19 μm. Furthermore, when the magnitude of the depth B of the concave portion C is greater than the height A of the convex portion P, the difference between the depth B and the height A is a maximum of 6 μm.

[0038] Like Fig. 2, Fig. 5 and Fig. 6 are views of the coil component viewed from the L direction. Fig. 2 shows a coil component 1 configured such that the height A of the convex portion P is greater than the depth B of the concave portion C. On the other hand, Fig. 5 shows a coil component 1 configured such that the depth B of the concave portion C is greater than the height A of the convex portion P. Fig. 6 also shows a coil component 1 configured such that the height A of the convex portion P is equal to the depth B of the concave portion C.

[0039] The shapes of the convex portions P and concave portions C of the coil component 1 may be any of those shown in FIG. 2, FIG. 5, and FIG. 6. For example, when the coil component 1 has a configuration as shown in FIG. 2, the sum A+B of the coil component 1 is greater than 0 μm. Also, for example, when the coil component 1 has a configuration as shown in FIG. 6, the sum A+B of the coil component 1 is 0 μm. In other words, the sum A+B can be 0 μm or greater. Also, for example, when the coil component 1 has a configuration as shown in FIG. 5, the sum A+B of the coil component 1 is less than 0 μm.

[0040] The convex shape of the convex portion P and the concave shape of the concave portion C can be confirmed by non-contact optical measurement using, for example, a hybrid laser microscope (OPTELICS HYBRID+) manufactured by Lasertec Corp. The optical measurement may be, for example, phase shift interferometry.

[0041] In this embodiment, the top surface 152 of the top plate 15 is a flat surface, but it does not have to be a flat surface. For example, the top surface 152 may be a concave curved surface that is recessed inward of the top plate 15. In this case, the "top surface" in the "direction parallel to the top surface of the top plate" described in the claims may be an imaginary plane connecting the periphery of the top surface 152 of the top plate 15. Also, for example, if the periphery of the top surface 152 of the top plate 15 is provided with a notch or is rounded, the "top surface" in the "direction parallel to the top surface of the top plate" described in the claims may be the portion of the top surface 152 excluding the portion with the notch or the rounded portion.

[0042] The above-described configuration is also true for the second flange 12. That is, the second flange 12 and the top plate 15 each have opposing surfaces that face each other. A first opposing surface 12f on the second flange 12 side is provided with a convex protrusion P that is convex toward the top plate 15 side when viewed from the direction of the axis AX. A second opposing surface 15f2 on the top plate 15 side is provided with a concave recess C that is concave in shape corresponding to the convex shape of the convex protrusion P of the second flange 12.

[0043] In the coil device 1, the convex shape of the convex portion P on the first flange 11 and the second flange 12 corresponds to the concave shape of the concave portion C on the top plate 15. This allows for a smaller distance between the second opposing surfaces 15f1 and 15f2 on the top plate 15 side and the first opposing surfaces 11f and 12f on the first flange 11 and second flange 12 side than when a core having convex portions on the upper surfaces of the first flange 11 and the second flange is combined with a top plate having a flat bottom. As a result, the magnetic resistance generated by the space between the second opposing surfaces 15f1 and 15f2 on the top plate 15 side and the first opposing surfaces 11f and 12f on the first flange 11 and second flange 12 side is reduced, thereby increasing the effective magnetic permeability and improving the coil characteristics. The coil characteristics include, for example, inductance and common-mode noise attenuation characteristic Scc21.

[0044] (Other preferred configurations) Fig. 7 is a VV cross-sectional view of Fig. 1. Fig. 7 is a cross-sectional view of the coil device 1 cut along the WT plane. The cross-section of Fig. 7 corresponds to "a cross-section perpendicular to the axial direction and intersecting with the first flange" as recited in the claims. For convenience, the adhesive 51 is omitted from Fig. 7.

[0045] 7, the uppermost portion P1 of the protrusion P of the first flange 11 is preferably disposed in the center of the first flange 11 in the W direction. With this configuration, even if the first flange 11 is disposed offset in the W direction with respect to the top plate 15, the distance between the second opposing surface 15f1 on the top plate 15 side and the first opposing surface 11f on the first flange 11 side can be more reliably reduced at the uppermost portion P1 of the protrusion P. Similarly, the uppermost portion P1 of the protrusion P of the second flange 12 may be disposed in the center of the second flange 12 in the W direction when viewed from the direction of the axis AX.

[0046] Preferably, (i) the uppermost portion C1 of the inner surface of the recess C, (ii) the uppermost portion P1 of the protrusion P, and (iii) at least one of both end portions of the recess C in the W direction are arranged in this order from the top plate 15 side. Specifically, in the T direction, the uppermost portion C1 of the inner surface of the recess C, the uppermost portion P1 of the protrusion P, and the first end portion CE1 of the recess C in the W direction are arranged in this order from the top plate 15 side. Also, in the T direction, the uppermost portion C1 of the inner surface of the recess C, the uppermost portion P1 of the protrusion P, and the second end portion CE2 of the recess C in the W direction are arranged in this order from the top plate 15 side. With this configuration, the distance between the second opposing surface 15f1 on the top plate 15 side and the first opposing surface 11f on the first flange 11 side can be more reliably reduced across the W direction.

[0047] Preferably, when viewed from the T direction, each of the convex portion P and the concave portion C has an area where they overlap each other, and the distance between the convex portion P and the concave portion C at both ends of the overlapping area in the W direction is greater than the distance between the convex portion P and the concave portion C at the center of the overlapping area in the W direction.

[0048] Specifically, the recess C has a region R1 that overlaps with the protrusion P when viewed from the T direction. The protrusion P has a region R2 that overlaps with the recess C when viewed from the T direction. The distance D2 between the protrusion P and the recess C at one end of the regions R1 and R2 in the W direction is greater than the distance D1 between the protrusion P and the recess C at the center of the regions R1 and R2 in the W direction. Furthermore, the distance D3 between the protrusion P and the recess C at the other end of the regions R1 and R2 in the W direction is greater than the distance D1 between the protrusion P and the recess C at the center of the regions R1 and R2 in the W direction. The distance D1 is, for example, 0 μm or more and 2 μm or less. A distance D1 of 0 μm means that the top plate 15 and the first flange portion 11 are in contact with each other at the center of the regions R1 and R2 in the W direction. The distances D2 and D3 are, for example, greater than 0 μm and equal to or less than 10 μm, more specifically, equal to or greater than 1 μm and equal to or less than 5 μm. With this configuration, the distance between the second opposing surface 15f1 on the top plate 15 side and the first opposing surface 11f on the first flange portion 11 side can be more reliably reduced at the centers of the regions R1 and R2 in the W direction. In particular, when the distances D2 and D3 are set to 10 μm or less, the coil characteristics of the coil device 1 can be further improved.

[0049] Preferably, the top of the inner surface of cutout 15n, the top C1 of the inner surface of recess C, the top P1 of protrusion P, and the ends CE1 and CE2 on the side where cutout 15n is provided, of both ends of recess C in the W direction, are arranged in this order from the top plate 15 side. The top of the inner surface of cutout 15n is the portion located at the uppermost position on the inner surface of cutout 15n.

[0050] Specifically, the inner surface of the notch 15n has an inner top surface 15n1 extending along the WL plane and an inner side surface 15n2 extending along the LT plane. In this embodiment, the inner top surface 15n1 is the uppermost part of the inner surface of the notch 15n. In the T direction, the inner top surface 15n1, the uppermost part C1 of the inner surface of the recess C, the uppermost part P1 of the protrusion P, and the ends CE1 and CE2 of both ends of the recess C in the W direction on the side where the notch 15n is provided are arranged in this order from the top plate 15 side. The shape of the inner surface of the notch 15n is not particularly limited. With this configuration, the size of the notch 15n can be increased, allowing more adhesive to be guided and stored in the notch 15n, thereby more reliably preventing the adhesive from spilling out of the coil component 1.

[0051] Preferably, when viewed from the T direction, the notch 15n overlaps with the protrusion P of the first flange 11. With this configuration, compared to a case where the notch 15n does not overlap with the protrusion P of the first flange 11, it is possible to prevent the adhesive 51 from leaking out of the coil device 1 from the ends CE1, CE2 of the recess C in the W direction, and it is possible to more reliably guide the adhesive 51 to the notch 15n.

[0052] 3, the recess C of the top plate 15 preferably extends to a region R3 of the bottom surface 151 of the top plate 15 that overlaps with the winding core portion 13 when viewed from the T direction. Specifically, the recess C of the top plate 15 extends in the L direction from the portion of the recess C provided in the second opposing surface 15f1 when viewed from the T direction, and is connected to the portion of the recess C provided in the second opposing surface 15f2.

[0053] According to the above configuration, even when first flange 11 is arranged shifted relative to top plate 15 toward region R3 overlapping with winding core 13, the distance between second opposing surface 15f1 on the top plate 15 side and first opposing surface 11f on the first flange 11 side can be reduced, thereby improving coil characteristics. Similarly, even when second flange 12 is arranged shifted relative to top plate 15 toward region R3 overlapping with winding core 13, the distance between second opposing surface 15f2 on the top plate 15 side and first opposing surface 12f on the second flange 12 side can be reduced, thereby improving coil characteristics.

[0054] FIG. 8 is a cross-sectional view illustrating the circle of curvature of the recess C of the top plate 15 and the circle of curvature of the protrusion P of the first flange portion 11. FIG. 8 is the same cross-section as FIG. 7. For convenience, the adhesive 51 and terminal electrodes 31 and 32 are omitted from FIG. 8. The radius of curvature r1 of the recess C of the top plate 15 is different from the radius of curvature r2 of the protrusion P of the first flange portion 11. As shown in FIG. 8, the radius of curvature r1 of the recess C of the top plate 15 is preferably larger than the radius of curvature r2 of the protrusion P of the first flange portion 11. The radius of curvature r1 is, for example, 70 mm. The radius of curvature r2 is, for example, 60 mm.

[0055] According to the above configuration, the distance between the second opposing surface 15f1 on the top plate 15 side and the first opposing surface 11f on the first flange 11 side can be more reliably reduced at the uppermost part P1 of the protrusion P in the T direction compared to when the radius of curvature r1 of the recess C of the top plate 15 is smaller than the radius of curvature r2 of the protrusion P of the first flange 11. Similarly, on the second flange 12 side, the radius of curvature of the recess C of the top plate 15 may be larger than the radius of curvature of the protrusion P of the second flange 12 when viewed from the direction of the axis AX. Note that the radius of curvature r1 of the recess C of the top plate 15 may be equal to or smaller than the radius of curvature r2 of the protrusion P of the first flange 11.

[0056] Preferably, the center CC1 of the circle of curvature CC of the recess C of the top plate 15 is located outside the first flange 11. With this configuration, the radius of curvature r1 of the recess C of the top plate 15 can be made larger compared to when the center CC1 of the circle of curvature CC of the recess C of the top plate 15 is located inside the first flange 11. This makes it easier to control the depth of the recess C when forming the top plate 15, and reduces the variation in the depth of the recess C. As a result, the variation in the coil characteristics can also be reduced. Similarly, on the second flange 12 side, the center of the circle of curvature of the recess C of the top plate 15 may be located outside the second flange 12 when viewed from the direction of the axis AX.

[0057] Preferably, the center PC1 of the circle of curvature PC of the convex portion P of the first flange 11 is located outside the first flange 11. With this configuration, the radius of curvature r2 of the convex portion P of the first flange 11 can be made larger compared to when the center PC1 of the circle of curvature PC of the convex portion P of the first flange 11 is located inside the first flange 11. This makes it easier to control the height of the convex portion P when molding the core 10, and reduces variation in the height of the convex portion P. As a result, variation in the coil characteristics can also be reduced. Similarly, on the second flange 12 side, the center of the circle of curvature of the convex portion P of the second flange 12 may be located outside the second flange 12 when viewed from the direction of the axis AX.

[0058] (Manufacturing method) Next, a method for manufacturing the coil component 1 will be described. a step of first press-molding a core material to form a core molded body, and firing the core molded body to form a core 10 having a protrusion P on a first flange 11; A step of forming a top plate 15 having a recess C by second press-molding the top plate material to form a top plate molded body and firing the top plate molded body; a step of winding a first wire 21 and a second wire 22 around a winding core portion 13 of a core 10; and combining the core 10 around which the first wire 21 and the second wire 22 are wound with the top plate 15.

[0059] Preferably, the first press molding compresses the core compact with one upper punch and one lower punch. This configuration makes it possible to easily form a convex portion on the first flange portion 11 of the core 10. Furthermore, the manufacturing cost can be reduced compared to when the core compact is compressed with multiple upper punches and multiple lower punches.

[0060] Preferably, the second press molding compresses the top plate molded body using one upper punch and one lower punch. This configuration allows the top plate molded body to be easily manufactured. Also, the manufacturing cost can be reduced compared to when the top plate molded body is compressed using multiple upper punches and multiple lower punches.

[0061] An example of a method for manufacturing the coil device 1 will be described in detail with reference to FIGS. 9A to 9F and 10A to 10C. FIGS. 9A to 9F are diagrams for explaining a method for forming a core molded body. FIGS. 10A to 10C are diagrams for explaining a method for forming a top plate molded body. FIGS. 9A to 9F correspond to the "first press molding" set forth in the claims. FIGS. 10A to 10C correspond to the "second press molding" set forth in the claims. Note that the method described below is an example, and the method for manufacturing the coil device 1 is not limited to the method described below.

[0062] <Core formation> As shown in FIG. 9A, a feeder (raw material supply unit) 61 filled with a core material 1010 is moved above a die 62. A lower punch 711 is disposed at the lower opening of the die 62. The upper surface of the lower punch 711 has a shape corresponding to the shape of the core 10 to be formed. The core material 1010 is, for example, ferrite powder.

[0063] As shown in FIG. 9B, the core material 1010 is filled into the die 62. As shown in FIG. 9C, after the feeder 61 has been removed after filling with the core material 1010, the upper punch 71u is placed on the die 62. The lower surface of the upper punch 71u has a shape corresponding to the shape of the core 10 to be formed. In addition, the lower surface of the upper punch 71u has a concave shape for forming the convex shape of the convex portion P of the first flange portion 11 and the second flange portion 12.

[0064] As shown in FIG. 9D , an upper punch 71u is inserted into the die 62, and the core material 1010 is compressed. This forms a core molded body 10m that will become the core 10. In this manner, the core molded body 10m is compressed using one upper punch 71u and one lower punch 71l. That is, the portion that will become the winding core 13, and the portions that will become the first flange 11 and the second flange 12 are simultaneously formed using one upper punch 71u and one lower punch 71l. However, this is not limited thereto, and the core molded body 10m may be compressed using multiple upper punches. Specifically, the portion that will become the winding core 13 may be formed using a first upper punch, and the portions that will become the first flange 11 and the second flange 12 may be formed using a second upper punch that is different from the first upper punch.

[0065] As shown in FIG. 9E, the upper punch 71u is moved upward. As shown in FIG. 9F, after removing the upper punch 71u, the lower punch 71l is moved upward to remove the core molded body 10m. The core molded body 10m has a first portion 11a that will become the first flange portion 11, a second portion 12a that will become the second flange portion 12, and a third portion 13a that will become the winding core portion 13. A protrusion P0 that will become the protrusion P is formed on the upper surface of the first portion 11a and the upper surface of the second portion 12a. The core molded body 10m is then fired to form the core 10 having the protrusions P on the first flange portion 11 and the second flange portion 12. Then, barrel polishing is performed to remove burrs. The bottom side of the core 10 is then dipped in Ag paste and fired, and then plated with a thin film of Cu / Ni / Sn to form the first to fourth terminal electrodes 31 to 34.

[0066] The method for forming the protrusions P is not limited to the above. For example, the powder density may be made non-uniform in the core molded body 10m, and the protrusions P may be formed after firing. Specifically, for example, in the core molded body 10m, the powder density of the first portion 11a that will become the first flange portion 11 and the powder density of the second portion 12a that will become the second flange portion 12 are made lower than the powder density of the third portion 13a that will become the winding core portion 13. The portion with lower powder density has a higher shrinkage rate after firing than the portion with higher powder density. Therefore, the shrinkage rate after firing is higher in the first portion 11a and the second portion 12a, and the protrusions P are formed in the first flange portion 11 and the second flange portion 12.

[0067] <Forming the top plate> As shown in Fig. 10A, the die 63 is filled with a top plate material 1015. A lower punch 72l is disposed in the opening on the lower side of the die 63. The upper surface of the lower punch 72l is shaped to correspond to the shape of the top plate 15 to be formed. The top plate material 1015 is, for example, ferrite powder.

[0068] As shown in FIG. 10B, the upper punch 72u is inserted into the die 63, and the top plate material 1015 is compressed. This forms a top plate formed body 15m that will become the top plate 15. In this manner, the top plate formed body 15m is compressed by one upper punch 72u and one lower punch 72l. The lower surface of the upper punch 72u has a shape corresponding to the shape of the top plate 15 to be formed. In addition, the lower surface of the upper punch 72u has a convex shape for forming the concave shape of the recess C of the top plate 15.

[0069] 10C, after removing the upper punch 72u, the lower punch 72l is moved upward to remove the top plate molded body 15m. A recess C0 that will become the recess C of the top plate 15 is formed on the top surface of the top plate molded body 15m. The top plate molded body 15m is then fired to form the top plate 15 having the recess C.

[0070] <Coil winding and coil component assembly> Thereafter, the first wire 21 and the second wire 22 are wound around the winding core portion 13 of the core 10 using a nozzle. Thereafter, the first wire 21 and the second wire 22 are crimped to the first to fourth terminal electrodes 31 to 34 using a heater tip. Thereafter, the top plate 15 is attached to the core 10 using adhesive 51, and the coil component 1 is manufactured.

[0071] [Second embodiment] Fig. 11 is a cross-sectional view showing a coil device according to a second embodiment. Fig. 11 corresponds to Fig. 7 of the first embodiment. The second embodiment differs from the first embodiment in that a convex portion is provided on the top plate side and concave portions are provided on the first flange side and the second flange side. The other configurations are the same as those of the first embodiment, and the same reference numerals as those of the first embodiment are used, and the description thereof will be omitted.

[0072] 11 , in coil component 1A of the second embodiment, second opposing surface 15f1 on the top plate 15A side is provided with convex portions P that are convex toward first flange 11A when viewed from the direction of axis AX. First opposing surface 11f on the first flange 11A side is provided with concave portions C that are concave corresponding to the convex shape of convex portions P of top plate 15A. Similarly, on the second flange side, second opposing surface 15f1 on the top plate 15A side is provided with convex portions P that are convex toward the second flange when viewed from the direction of axis AX, and first opposing surface 15f2 on the second flange side is provided with concave portions C that are concave corresponding to the convex shape of convex portions P of top plate 15A.

[0073] According to the above configuration, the convex shape of the convex portion P on the top plate 15A corresponds to the concave shape of the concave portion C on the first flange 11A and the second flange, so the distance between the second opposing surface on the top plate 15A side and the first opposing surfaces on the first flange 11A side and the second flange side can be made smaller than when a core having convex portions on the upper surface of the first flange 11A and the upper surface of the second flange is combined with a top plate having a flat bottom surface. As a result, the magnetic resistance generated by the space between the second opposing surface on the top plate 15A side and the first opposing surfaces on the first flange 11A side and the second flange side can be reduced, thereby improving the coil characteristics.

[0074] The present disclosure is not limited to the above-described embodiments, and design modifications are possible within the scope of the present disclosure.

[0075] In the above embodiment, the coil component has two wires, but may have one wire or three or more wires. Also, in the above embodiment, the coil component is used as a common mode choke coil, but may be used as a wire-wound coil in which the wire of a transformer, a coupled inductor, or the like is wound around a winding core.

[0076] In the first embodiment, a convex portion was provided on each of the first flange and the second flange, but the convex portion may be provided on only one of the first flange and the second flange. In this case, the concave portion only needs to be provided on at least the surface of the bottom surface of the top plate that faces the upper surface of the flange on the side where the convex portion is provided. Similarly, in the second embodiment, a concave portion was provided on each of the first flange and the second flange, but the concave portion only needs to be provided on only one of the first flange and the second flange. In this case, the convex portion only needs to be provided on at least the surface of the bottom surface of the top plate that faces the upper surface of the flange on the side where the concave portion is provided.

[0077] In the first embodiment, in a cross section perpendicular to the axial direction and intersecting with the first flange portion, the top of the inner surface of the recess, the top of the convex portion, and both end portions of the recess in a direction parallel to the top surface of the top plate were arranged in this order from the top plate side, but (i) the top of the inner surface of the recess, (ii) the top of the convex portion, and (iii) either end of both end portions of the recess in a direction parallel to the top surface of the top plate may also be arranged in this order from the top plate side.

[0078] In the first embodiment, the bottom surface of the top plate had notches at both ends perpendicular to the axial direction and parallel to the top surface of the top plate, but the bottom surface of the top plate may have a notch at only one of both ends perpendicular to the axial direction and parallel to the top surface of the top plate. [Example]

[0079] Multiple coil components were manufactured using the method described above. Each coil component had the configuration described above. The specific configuration of each coil component was as follows: The outer dimensions of the core 10 of each coil component were 3.2 mm × 2.5 mm × 1.5 mm. That is, in each coil component, the length in the L direction was 3.2 mm, the length in the W direction was 2.5 mm, and the length in the T direction was 1.5 mm. The thickness of the first flange portion 11 and the second flange portion 12 of each coil component was 0.7 mm. The cross section of the winding core portion 13 of the core 10 of each coil component was 1.0 mm × 1.0 mm. The size of the top plate 15 of each coil component was 3.2 mm × 2.5 mm × 0.7 mm. That is, in each coil component, the length in the L direction was 3.2 mm, the length in the W direction was 2.5 mm, and the length in the T direction was 0.7 mm. The relative permeability of the material constituting the core 10 and top plate 15 of each coil component was 1000. Each of the first wire 21 and the second wire 22 is wound around the core 10 30 times.

[0080] Each coil component has a different sum A+B. That is, while each coil component has a common configuration in terms of external size and the like, each coil component has a different sum A+B.

[0081] The inductance of each coil component was calculated by simulation. The results of the calculation are shown in FIG. 12. FIG. 12 is a graph showing the rate of decrease in inductance versus the combined value of the height of the convex portion and the depth of the concave portion. In FIG. 12, the horizontal axis represents the combined value A+B of the height of the convex portion and the depth of the concave portion. The rate of decrease in inductance indicates the percentage decrease in inductance relative to a coil component in which the combined value A+B=0 μm. For example, in the graph shown in FIG. 12, when the combined value of the height of the convex portion and the depth of the concave portion is 5 μm, the rate of decrease in inductance is −14.6%. This indicates that the inductance of a coil component in which the combined value A+B is 5 μm is 14.6% lower than the inductance of a coil component in which the combined value A+B is 0 μm.

[0082] As shown in Figure 12, the inductance of a coil component where the sum A+B is 0 μm is the highest. Also, the larger the sum A+B (in other words, the more positive the sum A+B), the lower the inductance. Also, the smaller the sum A+B (in other words, the more negative the sum A+B), the lower the inductance.

[0083] Here, in a plurality of coil components in which the rate of decrease in inductance is within 30%, the sum A+B is in the range RG1. In the range RG1, the sum A+B is not less than −6 μm and not more than 19 μm.

[0084] Furthermore, in a plurality of coil components in which the rate of decrease in inductance is within 20%, the sum A+B is in the range RG2, where the sum A+B is not less than −3 μm and not more than 8 μm.

[0085] Furthermore, in a plurality of coil components in which the rate of decrease in inductance is within 10%, the sum A+B is in the range RG3, where the sum A+B is not less than −1 μm and not more than 3 μm.

[0086] It is desirable that the rate of decrease in inductance is small. That is, in the above-described embodiment, the sum A+B is not less than −6 μm and not more than 19 μm, but is preferably not less than −3 μm and not more than 8 μm, and more preferably not less than −1 μm and not more than 3 μm.

[0087] The coil components described above can provide the following effects.

[0088] According to the embodiment, the rate of decrease in inductance can be reduced compared to coil components in which the sum A+B is less than -6 μm and coil components in which the sum A+B is greater than 19 μm. In other words, the inductance of the coil component can be increased. That is, the magnetic properties of the coil component can be improved.

[0089] In a configuration in which the sum A+B is greater than or equal to -3 μm and less than or equal to 8 μm, the rate of decrease in inductance can be made lower than in coil components in which the sum A+B is less than -3 μm and coil components in which the sum A+B is greater than 8 μm.

[0090] In a configuration where the sum A+B is greater than or equal to -1 μm and less than or equal to 3 μm, the rate of decrease in inductance can be made lower than in coil components where the sum A+B is less than -1 μm and coil components where the sum A+B is greater than 3 μm.

[0091] In a configuration in which the sum A+B is greater than 0 μm, the gap between the first and second opposing surfaces at their outer edges is larger than the gap at their central portions, making it easier to inject adhesive from the outer edges.

[0092] In a configuration in which the sum A+B is 0 μm, the gap between the first opposing surface and the second opposing surface can be made small, and therefore the inductance of the coil component can be made high.

[0093] In a configuration in which the sum A+B is less than 0 μm, the gap between the first and second opposing surfaces at the outer edges of the first and second opposing surfaces is smaller than the gap at the center of the first and second opposing surfaces. This increases the area where the gap is small, thereby increasing the inductance of the coil component.

[0094] According to the embodiment, the uppermost part P1 of the protrusion P is disposed in the center of the first flange 11 in the direction parallel to the top surface 152 of the top plate 15. In this case, even if the first flange 11 is disposed offset with respect to the top plate 15 in a direction perpendicular to the axis AX direction and parallel to the top surface 152 of the top plate 15, the distance between the second opposing surface 15f1 and the first opposing surface 11f can be more reliably reduced at the uppermost position of the protrusion P in the direction perpendicular to the top surface 152 of the top plate 15.

[0095] According to the embodiment, the convex portion P and the concave portion C have an arc shape. In this case, it is possible to reduce the variation in the gap between the first opposing surface 11f and the second opposing surface 15f1 depending on the position of the first opposing surface 11f on the WL plane.

[0096] According to the above embodiment, the distance between the second opposing surface 15f1 and the first opposing surface 11f can be more reliably reduced at the top P1 of the convex portion P in a direction perpendicular to the top surface 152 of the top plate 15, compared to when the radius of curvature r1 of the concave portion C of the top plate 15 is smaller than the radius of curvature r2 of the convex portion P of the first flange portion 11.

[0097] According to the embodiment, the top plate 15 has the cutout 15n, and therefore, when the core 10 and the top plate 15 are bonded together using the adhesive 51, the adhesive 51 can be guided and pooled in the cutout 15n. Therefore, even if an excessive amount of adhesive 51 is used, the adhesive 51 can be prevented from spilling out of the coil device 1.

[0098] According to the embodiment, when the first opposing surface 11f and the second opposing surface 15f1 are in contact with each other, the position of one of the core 10 and the top plate 15 can be stabilized relative to the other.

[0099] According to the embodiment, the core 10 and the top plate 15 can be fixed to each other.

[0100] The coil components described above can also be expressed as follows.

[0101] (1) A coil component according to one aspect of the present disclosure includes: a core having a winding core portion extending in an axial direction and a first flange portion and a second flange portion provided at both ends of the winding core portion in the axial direction; a coil wound around the winding core; a top plate provided so as to straddle the first flange portion and the second flange portion, the first flange portion has a first opposing surface that faces the top plate, the top plate has a second opposing surface that faces the first flange portion, In a cross section perpendicular to the axial direction and intersecting with the first flange portion, one of the first opposing surface and the second opposing surface is provided with a convex portion having a convex shape that is convex toward the other side of the first opposing surface and the second opposing surface, a recessed portion having a recessed shape that is recessed on the opposite side to one side of the first opposing surface and the second opposing surface is provided on the other of the second opposing surface and the second opposing surface, When the height of the convex portion is A (A>0) and the depth of the concave portion is B (B<0), the sum of the height of the convex portion and the depth of the concave portion, A+B, is greater than or equal to -6 μm and less than or equal to 19 μm.

[0102] (2) In the coil component of (1), The sum A+B may be equal to or greater than −3 μm and equal to or less than 8 μm.

[0103] (3) In the coil part of (2), The sum A+B may be equal to or greater than −1 μm and equal to or less than 3 μm.

[0104] (4) In any one of the coil components (1) to (3), The sum A+B may be 0 μm or more.

[0105] (5) In any one of the coil components (1) to (3), The sum A+B may be less than 0 μm.

[0106] (6) In any one of the coil components (1) to (5), The top plate may have a top surface opposite to the second opposing surface, In the cross section, the top of the protrusion may be located at the center of the first flange in a direction parallel to the top surface of the top plate.

[0107] (7) In any one of the coil components (1) to (6), In the cross section, the convex portion and the concave portion may have an arc shape.

[0108] (8) In any one of the coil components (1) to (7), In the cross section, the radius of curvature of the arc shape of the convex portion and the radius of curvature of the arc shape of the concave portion may be different.

[0109] (9) In any one of the coil components (1) to (8), The top plate may have a top surface opposite to the second opposing surface, and a bottom surface opposite to the top surface and including the second opposing surface, The bottom surface of the top plate may have a notch on at least one of both end portions in a direction perpendicular to the axial direction and parallel to the top surface of the top plate.

[0110] (10) In any one of the coil components (1) to (9), The core may have an opposing surface opposite to the first opposing surface, The top of the convex portion may be a flat portion configured substantially parallel to the opposite surface of the core.

[0111] (11) In any one of the coil components (1) to (10), A gap formed between the protrusion and the recess may be filled with adhesive.

[0112] (12) In any one of the coil components (1) to (11), The coil may include a first wire and a second wire.

[0113] Any of the various embodiments described above may be combined appropriately to achieve the effects of each of them.

[0114] While the present invention has been fully described in connection with preferred embodiments, with appropriate reference to the drawings, various changes and modifications will become apparent to those skilled in the art, and it is to be understood that such changes and modifications are included within the scope of the present invention as defined by the appended claims unless they depart therefrom. [Explanation of symbols]

[0115] 1. 1A coil parts 10 cores 10m core molding 11, 11A 1st collar part 11f: First opposing surface on the first flange side 12 Second flange 12f First opposing surface on the second flange side 13 Winding core 15, 15A top plate 15m top plate molding 15f1, 15f2 2nd opposing surface 15n notch 151 Bottom of the top plate 152 Top of the tabletop 21 First Wire 22 Second Wire 31 1st terminal electrode 32 2nd terminal electrode 33 3rd terminal electrode 34 4th terminal electrode 51 Adhesive 71l, 72l lower punch 71u, 72u upper punch 1010 Core Material 1015 Top plate material r1, r2 radius of curvature C recess C1 Top of the recess CE1, CE2 1st end, 2nd end D1~D3 distance P convex part P1 Top of the convex part CC, PC curvature circle CC1, PC1 Center of curvature circle R1 and R2 overlapping area R3 Area overlapping with the core AX Core shaft

Claims

1. a core having a winding core portion extending in an axial direction and a first flange portion and a second flange portion provided at both ends of the winding core portion in the axial direction; a coil wound around the winding core; a top plate provided so as to straddle the first flange portion and the second flange portion, the first flange portion has a first opposing surface that faces the top plate, the top plate has a second opposing surface that faces the first flange portion, In a cross section perpendicular to the axial direction and intersecting the first flange portion, a convex portion having a convex shape that is convex toward the other side of the first opposing surface or the second opposing surface is provided on one of the first opposing surface and the second opposing surface, a recessed portion having a recessed shape that is recessed on the opposite side to one side of the first opposing surface and the second opposing surface is provided on the other of the second opposing surface and the second opposing surface, When the height of the convex portion is A (A>0) and the depth of the concave portion is B (B<0), the sum A+B of the height of the convex portion and the depth of the concave portion is -6 μm or more and 19 μm or less.

2. The coil component according to claim 1, wherein the sum A+B is not less than −3 μm and not more than 8 μm.

3. The coil component according to claim 2, wherein the sum A+B is not less than −1 μm and not more than 3 μm.

4. The coil component according to claim 1 , wherein the sum A+B is equal to or greater than 0 μm.

5. The coil component according to claim 1 , wherein the sum A+B is less than 0 μm.

6. the top plate has a top surface opposite to the second opposing surface, The coil component according to claim 1 , wherein in the cross section, the uppermost portion of the protrusion is disposed at the center of the first flange in a direction parallel to the top surface of the top plate.

7. The coil component according to claim 1 , wherein the convex portion and the concave portion have an arc shape in the cross section.

8. The coil component according to claim 1 , wherein a radius of curvature of the arc shape of the convex portion and a radius of curvature of the arc shape of the concave portion are different in the cross section.

9. the top plate has a top surface opposite to the second opposing surface and a bottom surface opposite to the top surface and including the second opposing surface, The coil component according to claim 1 , wherein the bottom surface of the top plate has a notch on at least one of both end portions in a direction perpendicular to the axial direction and parallel to the top surface of the top plate.

10. the core has an opposing surface opposite to the first opposing surface, The coil component according to claim 1 , wherein the uppermost portion of the protrusion is a flat portion that is configured to be substantially parallel to the opposite surface of the core.

11. The coil component according to claim 1 , wherein a gap formed between the protrusion and the recess is filled with an adhesive.

12. The coil component according to claim 1 , wherein the coil includes a first wire and a second wire.

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