Manufacturing method of coil component, coil component, coil component intermediate, power transmission device, power reception device, and power transmission system

Abstract

To provide a manufacturing method of a coil component capable of suppressing variation in thickness and warping of the coil component.SOLUTION: A manufacturing method of a coil component 10 in an embodiment includes the steps: preparing a mold that has a plate-shaped main body portion 101 and a spiral-shaped protrusion protruding from a surface of the main body portion, and is recessed from a tip of the protrusion, and in which one or more notches opened from an inner side surface of the protrusion located on the center side of the spiral shape formed by the protrusion and an outer side surface opposite to the same; installing a spiral-shaped planar coil on the surface of the main body portion of the mold so as to fit the protrusion; installing a molten molding material so as to cover the planar coil and the mold; and hardening the molding material to produce a first coil holding member 20 that holds the planar coil 11.SELECTED DRAWING: Figure 6B

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a coil component, a coil component, an intermediate body of a coil component, a power transmission device, a power reception device, and a power transmission system.

Background Art

[0002] Wireless power transmission systems that transmit power without contact are becoming increasingly popular.

[0003] For example, a system is known that transmits power without contact by passing a high-frequency current through a resonant circuit including a coil.

[0004] When a high-frequency current flows through a coil, the skin effect can occur. The skin effect increases the AC resistance and thus causes a decrease in the transmission efficiency during power transmission. Considering this, when the coil is formed of Litz wire, the skin effect can be suppressed, and thus a decrease in the transmission efficiency can be suppressed. However, since Litz wire is formed by twisting a large number of enameled wires, the manufacturing cost is high and the manufacturing is time-consuming, and the manufacturing labor increases as the size of the coil increases.

[0005] On the other hand, a technique that employs a planar coil having a spiral shape and a plate shape and a rectangular cross-section of a conductor is also known (see Patent Document 1). Such a planar coil can be formed, for example, by punching out from a plate material. Therefore, according to such a planar coil, the manufacturing efficiency can be improved regardless of the size of the coil. It is also advantageous in terms of thinning and weight reduction of the device incorporating the coil.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Patent Document 1 discloses a structure in which a magnetic body protruding in the axial direction of a planar coil from between turn portions that constitute the planar coil is provided between the turn portions. According to this structure, performance such as the Q value can be improved. On the other hand, when the planar coil is formed from a plate material as described above, the planar coil is likely to warp. Therefore, the planar coil may be held by a plate-shaped coil holding member made of a molding material such as resin to suppress warping. Here, when the magnetic body and the coil holding member as described above are used in combination, a groove for housing the magnetic body may be formed in the coil holding member.

[0008] When providing a groove for housing the protruding portion of the magnetic body in the coil holding member, the groove may be formed in a spiral shape along the spiral planar coil. In this case, for example, the coil holding member may be formed using a mold having a plate-shaped base portion and a spiral convex portion protruding from the base portion, and the groove may be formed by the convex portion.

[0009] However, when forming the coil holding member as described above, the continuous extension of the convex portion in a spiral shape impairs the flow of the molding material, particularly the flow in the radial direction. Due to this, the thickness of the coil holding member may vary. Further, when a continuously extending spiral groove is formed in the coil holding member, the coil holding member is likely to warp during the curing of the molding material. Variations in the thickness and warping of the coil holding member may, for example, form unnecessary gaps, thus potentially degrading the finish of the completed product.

[0010] In view of the above points, an object of the present disclosure is to provide a method for manufacturing a coil component, a coil component, an intermediate body of a coil component, a power transmission device, a power reception device, and a power transmission system that can suppress variations in the thickness and occurrence of warping of the coil component.

Means for Solving the Problems

[0011] Embodiments of the present disclosure relate to the following [1] to

[12] .

[0012] [1] Prepare a mold having a plate-shaped main body portion and a spiral convex portion protruding from the surface of the main body portion, with a recess at the tip of the convex portion and one or more notches formed that open from the inner surface of the convex portion located on the central side of the spiral shape formed by the convex portion and the outer surface on the opposite side thereof. Install a spiral planar coil on the surface of the main body portion of the mold along the convex portion. Install a molten molding material so as to cover the planar coil and the mold. By curing the molding material, a spiral groove corresponding to the convex portion is formed, and at a position corresponding to the notch in the groove, a raised portion is formed that partially fills the groove to divide the groove or partially shallow the depth of the groove, and a step of producing an intermediate body composed of a first coil holding member and the planar coil integrated with the first coil holding member.

[0013] [2] A plurality of the notches are formed in the mold. The plurality of notches include one or more notch groups composed of a plurality of the notches arranged in the radial direction of the spiral shape formed by the convex portion or in a direction parallel to the radial direction. The manufacturing method of the coil component according to [1].

[0014] [3] The plurality of notches include a plurality of notch groups arranged at regular angles in the circumferential direction around the center of the spiral shape formed by the convex portion, and each of the plurality of notch groups is arranged in the radial direction. The manufacturing method of the coil component according to [2].

[0015] [4] When viewed in the axial direction of the spiral shape formed by the convex portion, the convex portion includes a plurality of straight portions extending linearly, and the plurality of straight portions are sequentially connected so that one of the adjacent straight portions is bent with respect to the other to form a spiral shape. The notch is formed between both ends of the straight portion. The manufacturing method of the coil component according to any one of [1] to [3].

[0016] [5] The mold is used in which the ratio of the volume of all the notches to the reference volume obtained by adding the volume of the convex portions and the volume of all the notches is less than 10%, and the method for manufacturing a coil component according to any one of [1] to [4].

[0017] [6] A step of installing a molten magnetic resin material containing a magnetic material and a resin so as to fill the groove of the first coil holding member and cover the planar coil held by the first coil holding member on the intermediate body; By curing the magnetic resin material, a plate-shaped spacer portion extending and expanding in the radial direction of the spiral shape formed by the planar coil, and a spiral wall portion formed from the filling portion of the magnetic resin material into the groove and protruding from the spacer portion are included. A step of manufacturing a second coil holding member; A method for manufacturing a coil component according to any one of [1] to [5], wherein a recess recessed toward the spacer portion side is formed at a position corresponding to the raised portion of the first coil holding member in the wall portion.

[0018] [7] Further comprising a step of overlapping a second coil holding member on a magnetic shield member formed by laying a plurality of ferrite plates; The position of the notch in the mold and the shape of the plurality of ferrite plates are adjusted so that the boundary between adjacent ferrite plates overlaps with the recess in the wall portion. The method for manufacturing a coil component according to [6].

[0019] [8] A first coil holding member in which a spiral groove is formed and a raised portion is formed to partially fill and divide the groove or partially shallow the depth of the groove; A planar coil having a spiral shape disposed in a portion without the groove in the first coil holding member and extending along the groove; A second coil holding member including a plate-shaped spacer portion and a spiral wall portion protruding from the spacer portion, and sandwiching the planar coil between the second coil holding member and the first coil holding member; The wall portion is accommodated in the groove through the planar coil. The wall portion has a recess recessed toward the spacer portion at a position corresponding to the raised portion, and is a coil component.

[0020] [9] A first coil holding member in which a spiral groove is formed and a raised portion is formed to partially fill and divide the groove or to shallower the depth of the groove, and A planar coil having a spiral shape disposed in a portion of the first coil holding member without the groove and extending along the groove, and a coil component intermediate body.

[0021]

[10] A power transmission device including the coil component according to [8].

[0022]

[11] A power reception device including the coil component according to [8].

[0023]

[12] A power transmission system including a power transmission device and a power reception device, and At least one of the power transmission device and the power reception device includes the coil component according to [8].

Advantages of the Invention

[0024] According to the present disclosure, variations in the thickness and warpage of the coil component can be suppressed.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14A

Figure 14B

Figure 15

MODE FOR CARRYING OUT THE INVENTION

[0026] Hereinafter, an embodiment will be described with reference to the drawings.

[0027] In this specification, terms such as "sheet", "film", and "plate" are not distinguished from each other based only on the difference in name. Therefore, for example, "sheet" is a concept that includes members that can also be called films or plates.

[0028] <Wireless Power Transmission System> FIG. 1 schematically shows a wireless power transmission system S to which a coil component 10 according to an embodiment is applied. First, as an example, the wireless power transmission system S (hereinafter abbreviated as the power transmission system S) to which the coil component 10 is applied will be described with reference to FIG. 1.

[0029] The power transmission system S includes a power transmission device 1 and a power reception device 2. The power transmission device 1 includes a coil component 10 and a high-frequency current supply unit 1A. The coil component 10 in the power transmission device 1 functions as a power transmission coil. The high-frequency current supply unit 1A supplies a high-frequency current to the coil component 10 as a power transmission coil.

[0030] The power reception device 2 includes a coil component 10 and a conversion unit 2A. The coil component 10 in the power reception device 2 functions as a power reception coil. The conversion unit 2A shapes the high-frequency current generated in the coil component 10. The conversion unit 2A has a rectifier circuit or the like that converts the high-frequency current into a direct current. The conversion unit 2A may be configured to include, for example, a full-wave rectifier circuit including a plurality of diodes and a smoothing capacitor.

[0031] In this embodiment, each of the power transmission device 1 and the power reception device 2 includes the coil component 10. However, the coil component 10 may be used only in one of the power transmission device 1 and the power reception device 2, and a different type of coil component may be used in the other.

[0032] When wireless (non-contact) power is transmitted from the power transmission device 1 to the power reception device 2, the power transmission device 1 supplies a high-frequency current of a predetermined frequency from the high-frequency current supply unit 1A to the coil component 10 as a power transmission coil. At this time, a magnetic field is generated in the coil component 10 by electromagnetic induction. Then, due to the influence of this magnetic field, a high-frequency current is generated in the coil component 10 as a power reception coil in the power reception device 2. That is, the power reception device 2 receives the magnetic field from the power transmission device 1 or is affected by the magnetic field in the power transmission device 1, and passes a high-frequency current through electromagnetic induction. The conversion unit 2A converts this high-frequency current into a direct current and supplies the converted direct current to, for example, a battery (not shown).

[0033] The power transmission system S shown in FIG. 1 adopts a magnetic resonance method as the power transmission method. However, the coil component 10 according to the present embodiment may be used in a power transmission system of an electromagnetic induction method. Further, the power transmission system S is configured as a system for wirelessly transmitting power to an electric vehicle. In this case, the power transmission device 1 is installed on a road, a parking lot, or the like. The power reception device 2 is installed on an electric vehicle.

[0034] However, the application of the power transmission system S is not limited to power transmission to an electric vehicle. For example, the power transmission system S may be used for power transmission to a flying object such as a drone or a robot. Further, the power transmission system S may be used for power transmission to a submarine or an exploration robot in the sea. Further, the application of the coil component 10 is not limited to a wireless power transmission system. For example, the coil component 10 may be used for a transformer, a DC-DC converter, an antenna, or the like.

[0035] <Coil component> FIG. 2 is a perspective view of the coil component 10 according to the present embodiment. FIG. 3 is a plan view of the coil component 10. FIG. 4 is a cross-sectional view of the coil component 10 corresponding to the line IV-IV in FIG. 3.

[0036] Referring to FIGS. 2 to 4, the coil component 10 includes a planar coil 11, a first coil holding member 20, a second coil holding member 30, a first magnetic shield member 40, a second magnetic shield member 50, a first connection terminal 61, and a second connection terminal 62.

[0037] The planar coil 11 is held in a state of being sandwiched between the first coil holding member 20 and the second coil holding member 30. In FIG. 2, a state where the first coil holding member 20 is separated from the planar coil 11 and the second coil holding member 30 is shown. In FIG. 3, the illustration of the first coil holding member 20 is omitted. Also, in FIGS. 2 and 3, the illustration of the second magnetic shield member 50 is omitted. Hereinafter, each part of the coil component 10 will be described in detail.

[0038] (Planar Coil) As shown in FIGS. 2 to 4, the planar coil 11 is formed in a spiral shape. Specifically, the planar coil 11 includes a conductor 11E formed in a spiral shape around an arbitrary central axis C. The spiral shape means a shape of a planar curve that moves away from the center (or approaches the center) as it rotates. In the illustrated embodiment, the spiral shape is located on a virtual plane orthogonal to the central axis C.

[0039] Hereinafter, the axial direction means a direction extending on the central axis C or a direction parallel to the central axis C. Also, the radial direction means a radial direction of a circle drawn on a plane orthogonal to the central axis C with an arbitrary point on the central axis C as the center. Further, the circumferential direction means a direction along a circle centered on the central axis C (the circumferential direction of the circle).

[0040] The conductor 11E is formed of a conductive material. In the present embodiment, the conductor 11E is formed of copper, but it is not limited thereto. The conductor 11E may be formed of a copper alloy, aluminum, an aluminum alloy, or the like. In the present embodiment, the planar coil 11 is composed only of the conductor 11E. Therefore, the planar coil 11 is formed of copper, but it may be formed of a copper alloy, aluminum, an aluminum alloy, or the like.

[0041] The planar coil 11 (conductor 11E) is plate-shaped. Specifically, the planar coil 11 is a non-Litz wire planar coil. As shown in FIG. 4, the cross-sectional shape of the conductor in the direction orthogonal to the circumferential direction of the spiral shape of the planar coil 11 (conductor 11E) is rectangular.

[0042] The planar coil 11 includes a plurality of turn portions 11n arranged in a direction orthogonal to the central axis C of the spiral shape. The conductor 11E is composed of the plurality of turn portions 11n. The plurality of turn portions 11n are connected so as to gradually separate from the central axis C toward the outer side in the radial direction from the central axis C. Thereby, the plurality of turn portions 11n form a spiral shape as a whole.

[0043] Basically, the turn portion 11n is shaped such that a linear conductor portion does not form a loop and turns 360 degrees around the central axis C. In the case of a so-called planar coil, both ends of the turn portion 11n are displaced in the radial direction. In the plurality of turn portions 11n, the inner end in the radial direction of another turn portion 11n is connected to the outer end in the radial direction of a certain turn portion 11n. Thereby, the plurality of turn portions 11n extend away from the central axis C as a whole. The inner side in the radial direction means the direction approaching the central axis C in the radial direction. Also, the outer side in the radial direction means the direction away from the central axis C in the radial direction.

[0044] In the present embodiment, the turn portion 11n turns so as to form a polygon. Note that the spiral shape referred to in this specification and the present disclosure means the shape of a planar curve wound in a spiral. The planar curve referred to here includes a planar pattern that repeatedly turns while bending in a polygonal line shape as shown in the figure. In other words, the spiral shape means the shape of a planar curve that moves away from the center (or approaches the center) as it turns.

[0045] In the illustrated example, the planar coil 11 (conductor 11E) includes first to eighth turn portions 111 to 118. The first to eighth turn portions 111 to 118 are arranged in this order from the inner position in the radial direction toward the outer side. In other words, the first turn portion 111 is located at the innermost position in the radial direction, and the eighth turn portion 118 is located at the outermost position in the radial direction. More specifically, the first turn portion 111 forms the innermost peripheral portion of the planar coil 11 (conductor 11E). Also, the eighth turn portion 118 forms the outermost peripheral portion of the planar coil 11 (conductor 11E). When explaining matters common to each of the plurality of turn portions 11n below, they are referred to as turn portion 11n or turn portions 111 to 118.

[0046] Each of the turn portions 111 to 118 extends on the virtual plane. The first to eighth turn portions 111 to 118 are connected in this order, and thereby the planar coil 11 (conductor 11E) forms a spiral shape. In the illustrated example, the conductor 11E is octagonal as a whole. The conductor 11E is wound such that each of the turn portions 111 to 118 generally forms an octagon. However, the shape of the conductor 11E is not limited to this. The conductor 11E may be a polygon other than octagonal as a whole (for example, a quadrilateral, a hexagon, a dodecagon). In this case, each of the turn portions 111 to 118 may be wound so as to generally form a polygon other than octagonal (for example, a quadrilateral, a hexagon, a dodecagon). Also, the conductor 11E may be circular as a whole. In this case, each of the turn portions 111 to 118 may be wound so as to generally form a circle.

[0047] One end of each of the turn portions 111 to 118 is located more inward in the radial direction than the other end of the turn portion 111 to 118. In other words, the other end of each of the turn portions 111 to 118 is located more outward in the radial direction than the one end of the turn portion 111 to 118.

[0048] As shown in FIG. 3, each turn portion 111 to 118 includes a plurality of straight portions st1 to st9 arranged around the central axis C. The straight portions st1 to st9 each extend linearly when viewed in the axial direction. The straight portions st1 to st9 adjacent to each other in the circumferential direction of a circle centered on the central axis C are connected to each other. In each of the turn portions 111 to 118, a spiral planar coil 11 is formed by sequentially connecting the plurality of straight portions st1 to st9 such that one of the adjacent straight portions bends with respect to the other. In the illustrated example, the first to seventh turn portions 111 to 117 include the first to ninth straight portions st1 to st9. In contrast, the eighth turn portion 118 includes the first to eighth straight portions st1 to st8, but does not include the ninth straight portion st9. In the first to seventh turn portions 111 to 117, the first to ninth straight portions st1 to st9 are arranged in this order along the circumferential direction. In the eighth turn portion 118, the first to eighth straight portions st1 to st8 are arranged in this order along the circumferential direction.

[0049] The end portion of the first straight portion st1 on the side not connected to the second straight portion st2 forms the radially inner end portion of each of the turn portions 111 to 118. In the first to seventh turn portions 111 to 117, the end portion of the ninth straight portion st9 on the side not connected to the eighth straight portion st8 forms the radially outer end portion of the first to seventh turn portions 111 to 117. The ninth straight portion st9 extends parallel to the first straight portion st1 outside the first straight portion st1 in the radial direction. In the eighth turn portion 118, the end portion of the eighth straight portion st8 on the side not connected to the seventh straight portion st7 forms the radially outer end portion. The first to seventh turn portions 111 to 117 connect their respective radially outer end portions to the radially inner end portions of the second to eighth turn portions 118 adjacent to each other on the radially outer side.

[0050] The planar coil 11 (conductor 11E) described above is formed, as an example, by punching out a spiral shape from a metal plate such as a copper plate or an aluminum plate. On the other hand, the planar coil 11 can also be formed by etching a metal foil such as a copper foil or an aluminum foil into a spiral shape.

[0051] The radius of the planar coil 11 (the distance from the central axis C to the portion farthest in the radial direction) may be 80 mm or more and may be 450 mm or less. When the coil component 10 is used as a power transmission coil component or a power reception coil component of a power transmission system S that transmits power to an electric vehicle by a magnetic resonance method, the radius of the planar coil 11 may be 200 mm or more and 350 mm or less.

[0052] The thickness of the planar coil 11 (conductor 11E) is measured along the axial direction of the planar coil 11. The thickness of the planar coil 11 (the thickness of the conductor 11E) may be, for example, 0.1 mm or more and 2.0 mm or less, may be 0.2 mm or more and 1.0 mm or less, or may be 0.3 mm or more and 0.7 mm or less. The thickness of the planar coil 11 (conductor 11E) may be, for example, 0.15 mm or more and 0.35 mm or less. When transmitting power to an electric vehicle by a magnetic resonance method, it is desirable to be able to transmit power of 1 kW or more, preferably 5 kW or more, in a frequency range of a high-frequency current of 10 kHz to 200 kHz, particularly 79 kHz to 90 kHz. In this case, the thickness of the planar coil 11 formed of copper is preferably 0.4 mm or more.

[0053] The line width of the planar coil 11 (conductor 11E) is not particularly limited. However, considering that it is possible to transmit power of 1 kW or more, preferably 5 kW or more, in a frequency range of a high-frequency current of, for example, 79 kHz to 90 kHz, the line width of each turn portion 111 to 118 may be 2 mm or more and 20 mm or less, may be 2 mm or more and 16 mm or less, 2 mm or more and 12 mm or less, or 2 mm or more and 8 mm or less. Note that the line width means the distance between the inner peripheral surface and the outer peripheral surface of the linear portion of the planar coil 11 (conductor 11E) in a cross section orthogonal to the direction in which the planar coil 11 (conductor 11E) turns.

[0054] In addition, the aspect ratio of the planar coil 11 (conductor 11E) having a rectangular cross-sectional shape is determined by dividing the line width of the planar coil 11 (conductor 11E) (the width in the radial direction of each turn portion 11n) by the thickness of the planar coil 11 (conductor 11E). The aspect ratio of the planar coil 11 (conductor 11E) may be 2 or more and 12 or less, or may be 3 or more and 10 or less.

[0055] The thickness and line width of the planar coil 11 (conductor 11E) may be measured by measuring each part of the planar coil 11 (conductor 11E) with a ruler or the like on a cross section obtained by axially cutting the coil component 10 to expose the planar coil 11 (conductor 11E), or may be measured by analyzing a cross-sectional image.

[0056] Note that the central axis C is defined as follows in the present embodiment. First, a linear virtual turn portion having a shape similar to that of the innermost turn portion 111 is sequentially drawn inward in the radial direction from the inner end portion in the radial direction of the innermost turn portion 111 in a spiral shape. Then, the drawing is continued until a virtual turn portion that can be accommodated within a diameter of 1 cm is drawn. And a region inward in the radial direction of the virtual turn portion that can be accommodated within a diameter of 1 cm is defined as the central axis C by a line passing through the circumferential direction and the direction orthogonal to the radial direction of the spiral shape.

[0057] (First Coil Holding Member) The first coil holding member 20 is a member that overlaps the planar coil 11 in the axial direction and holds the planar coil 11. In the present embodiment, the first coil holding member 20 is formed by curing a molding material in a molten state. The molding material in the molten state is cured from a state in contact with the planar coil 11. Thereby, the first coil holding member 20 is integrated with the planar coil 11 and holds the planar coil 11. The structure in which the first coil holding member 20 and the planar coil 11 are integrated may be hereinafter referred to as an intermediate body 10M.

[0058] In the coil component 10, for example, when transmitting power, the magnetic field generated in the planar coil 11 is passed through the first holding member 20. Therefore, the first coil holding member 20 is preferably non-conductive (insulating) and non-magnetic in order not to interfere with the magnetic field and not to generate eddy currents.

[0059] Considering the preferable points of being non-conductive (insulating) and non-magnetic, the material of the first coil holding member 20 is, for example, an insulating resin or may be a fiber-reinforced plastic. More specifically, the material of the first coil holding member 20 may be a glass fiber-reinforced polyamide. However, the material of the first coil holding member 20 is not particularly limited. For example, it may not contain glass fibers. Also, a thermoplastic resin or a thermosetting resin other than polyamide may be used. Note that the insulating property means that the volume resistivity is 10 10 Ω·m or more. The non-magnetic property means not showing magnetism.

[0060] FIG. 5A is a plan view of the first coil holding member 20. FIG. 5B shows a partial perspective view of the first coil holding member 20. The shape of the first coil holding member 20 in plan view is a quadrangular shape, and when the first coil holding member 20 overlaps with the planar coil 11 in the axial direction, it covers the entire planar coil 11.

[0061] As shown in FIGS. 4, 5A, and 5B, a spiral groove 21 is formed in the first coil holding member 20. Further, a plurality of ridges 22 are formed in the groove 21 to partially fill the groove 21 to divide the groove 21 or to partially shallower the depth of the groove 21. The groove 21 is formed so as to be recessed from the surface of the first coil holding member 20 that overlaps with the planar coil 11. An installation area 23 for holding the planar coil 11 is formed in a portion of the surface of the first coil holding member 20 that overlaps with the planar coil 11 where the groove 21 is not formed.

[0062] Although details will be described later, a wall portion 32 that protrudes toward the first coil holding member 20 beyond the planar coil 11 is formed in the second coil holding member 30. The groove 21 forms a space for accommodating the wall portion 32. A recess 33 that is recessed from the tip is formed in the wall portion 32. The ridge 22 that fills the groove 21 in the first coil holding member 20 to divide the groove 21 or shallower the depth of the groove 21 is positioned so as to enter the recess 33 of the wall portion 32.

[0063] In this embodiment, the raised portion 22 fills the groove 21 and divides the groove 21. The state where the raised portion 22 fills the groove 21 and divides the groove 21 means a state where the raised portion 22 completely fills a part of the groove 21. The raised portion 22 is formed so as to connect the opposing side surfaces of a part of the groove 21. The "between the side surfaces" means between the side surface at a position close to the center of the spiral shape in a part of the groove 21 and the side surface facing this. The raised portion 22 can function as a rib that reinforces the strength and rigidity that can be reduced by the groove 21. Thereby, it becomes difficult for the first coil holding member 20 to bend, and the shape retention performance is improved.

[0064] In this embodiment, as shown in FIG. 5A, a plurality of raised portion groups 22G each composed of a plurality of raised portions 22 arranged in the radial direction are formed in the first coil holding member 20. Specifically, four raised portion groups 22G are formed at regular angles (90 degrees) in the circumferential direction of the spiral shape. However, the number and position of the raised portions 22 are not particularly limited.

[0065] As described above, the first coil holding member 20 is formed by curing a molten molding material. Specifically, although it will be described in detail later, the first coil holding member 20 is formed by supplying a molten molding material to a mold 100 (see FIGS. 6A and 6B) having a convex portion 102 in a spiral shape and curing it. A notch 103 that is recessed from the tip is formed in the convex portion 102 of the mold 100. The groove 21 is formed by the convex portion 102, and the raised portion 22 is formed by the notch 103. Here, the notch 103 of the convex portion 102 in the mold 100 ensures good fluidity of the molding material and enables the molding material to be uniformly spread on the mold 100. Thereby, the finish of the first coil holding member 20 becomes good.

[0066] Note that the raised portion 22 of the first coil holding member 20 is formed corresponding to the notch 103 formed in the mold 100 to improve the fluidity of the molding material. However, as described above, the raised portion 22 exhibits a reinforcing function in the first coil holding member 20. Therefore, the raised portion 22 is not formed merely for the convenience of the manufacturing process, but exhibits technical effects independent of the manufacturing process.

[0067] (Second Coil Holding Member) The second coil holding member 30 is a member that sandwiches the planar coil 11 between it and the first coil holding member 20 and holds the planar coil 11. The second coil holding member 30 overlaps the planar coil 11 in the axial direction of the planar coil 11.

[0068] As shown in FIGS. 2 to 4 and FIG. 5B, the second coil holding member 30 includes a plate-like spacer portion 31 that extends and spreads in the radial direction of the planar coil 11, and a spiral wall portion 32 that protrudes from the surface of the spacer portion 31 that overlaps the planar coil 11.

[0069] The second coil holding member 30 has magnetism and has the function of suppressing magnetic field penetration and / or leakage magnetic field. Specifically, the second coil holding member 30 has magnetism and insulation. The magnetic field generated in the coil component 10 is generated so as to spread in all directions with respect to the central axis C of the planar coil 11. At this time, since the second coil holding member 30 has magnetism, the magnetic flux lines that attempt to spread can be oriented toward the central axis C side. Also, when the magnetic field generated in the coil component 10 reaches the peripheral components located around the coil component 10, it may have an adverse effect on the peripheral components. Therefore, the second coil holding member 30 is provided to suppress the reach of the magnetic force lines to the peripheral components. Thereby, the second coil holding member 30 can suppress the leakage magnetic field that does not contribute to the generation of current.

[0070] The second coil holding member 30 is in contact with the planar coil 11 in a region where there is no wall portion 32 on the surface overlapping with the planar coil 11 of the spacer portion 31. And the wall portion 32 protrudes toward the first coil holding member 20 side, which is the direction away from the spacer portion 31 beyond the planar coil 11. In the second coil holding member 30, the wall portion 32 also has magnetism. Such a wall portion 32 can improve the performance such as the coupling coefficient and Q value of the coil component 10.

[0071] Referring to FIGS. 4 and 5B, the wall portion 32 is accommodated in the groove 21 in the first coil holding member 20. And a recess 33 that is recessed from the tip toward the spacer portion 31 side is formed in the wall portion 32. The wall portion 32 has the recess 33 at a position corresponding to the raised portion 22 in the first coil holding member 20. And when the first coil holding member 20, the planar coil 11, and the second coil holding member 30 are integrated, the raised portion 22 is positioned so as to enter into the recess 33 of the wall portion 32. The arrangement pattern of the recesses 33 is the same as the arrangement pattern of the raised portions 22. Therefore, the plurality of recesses 33 include a plurality of recess groups 33G each composed of a plurality of recesses 33 arranged in the radial direction as shown in FIG. 3. Specifically, four recess groups 33G are formed at regular angles (90 degrees) in the circumferential direction of the spiral shape. However, the number and position of the recesses 33 are not particularly limited.

[0072] Here, when the number or volume of the raised portions 22 increases, the number or volume of the recesses 33 increases, and the volume of the wall portion 32 decreases. When the volume of the wall portion 32 decreases, the performance improvement effects such as the coupling coefficient and Q value by the wall portion 32 decrease. Therefore, it is not desirable that the number or volume of the raised portions 22 becomes excessively large. Also, it is not desirable that the raised portions 22 are concentrated and formed in a specific range. As a result of intensive research, the inventor of the present invention has found that the ratio of the volume of the raised portions 22 to the volume of the groove 21 in a state where there are no raised portions 22 is desirably less than 10%. In this case, the performance improvement effect by the wall portion 32 can be obtained favorably, and good moldability, strength, and rigidity of the first coil holding member 20 can be ensured.

[0073] The second coil holding member 30 includes, as an example, a holding material containing resin and a plurality or innumerable magnetic particles made of a magnetic material. The magnetic particles are held by the holding material. The holding material is insulating, specifically non-magnetic and insulating. Note that the term "insulating" means that the volume resistivity is 10 10

[0074] As the resin for forming the holding material of the second coil holding member 30, for example, thermosetting resins such as epoxy resin and polyimide can be adopted. Also, as the resin for forming the second coil holding member 30, thermoplastic resins such as nylon, polyethylene, and polypropylene can also be adopted. Further, the holding material may include, for example, fiber-reinforced plastic or may be formed from fiber-reinforced plastic. For example, the holding material may include glass fiber-reinforced polyamide or may be formed from glass fiber-reinforced polyamide.

[0075] The magnetic particles of the second coil holding member 30 may be formed from any one or two or more of ferrite, particularly ferrite of a soft magnetic material, nanocrystalline magnetic material, silicon steel, electromagnetic soft iron, and amorphous metal.

[0076] The relative permeability of the second coil holding member 30 is preferably 2.0 or more, and may be 2.0 or more and 20.0 or less. The relative permeability of the second coil holding member 30 is more preferably 5.0 or more, and may be 5.0 or more and 20.0 or less. The relative permeability of the second coil holding member 30 is not particularly limited, but if it is too large, the flexibility and strength of the second coil holding member 30 may be undesirably impaired. Therefore, the relative permeability of the second coil holding member 30 may be 30 or less.

[0077] (The first magnetic shielding member) The first magnetic shielding member 40 is provided for magnetic transmission and / or suppression of leakage magnetic fields. As shown in FIG. 4, the first magnetic shielding member 40 is overlapped on the surface opposite to the surface overlapping the planar coil 11 in the second coil holding member 30. The first magnetic shielding member 40 is formed in a plate shape and extends along the radial direction of the planar coil 11. The first magnetic shielding member 40 has a size such that, when viewed in the axial direction, its outer peripheral edge is located outside the second coil holding member 30 and the planar coil 11. In the illustrated example, the first magnetic shielding member 40 is rectangular when viewed in the axial direction.

[0078] The first magnetic shielding member 40 contains a magnetic material. As described above, the magnetic field generated in the coil component 10 is generated so as to spread in all directions with respect to the central axis C of the planar coil 11. At this time, since the first magnetic shielding member 40 has magnetism, the magnetic flux lines trying to spread can be oriented toward the central axis C side. Further, the first magnetic shielding member 40 suppresses the magnetic field from reaching the peripheral components. Thereby, the first magnetic shielding member 40 can suppress the leakage magnetic field that does not contribute to the generation of current.

[0079] The first magnetic shielding member 40 preferably contains a soft magnetic material. More specifically, the first magnetic shielding member 40 contains ferrite, preferably soft ferrite. Further, the first magnetic shielding member 40 may contain a nanocrystalline magnetic material.

[0080] The relative permeability of the first magnetic shielding member 40 is not particularly limited, but is preferably 100 or more, and may be 100 or more and 10,000 or less. The relative permeability of the first magnetic shielding member 40 may be 1000 or more, may be 2000 or more, or may be 3000 or more. The relative permeability of the first magnetic shielding member 40 may be 8000 or less, may be 6000 or less, or may be 4000 or less.

[0081] In the example shown in FIG. 4, the first magnetic shield member 40 is in contact with the second coil holding member 30, but it is not limited thereto. The first magnetic shield member 40 may be separated from the second coil holding member 30. When the first magnetic shield member 40 is arranged to be separated from the second coil holding member 30, the distance between the first magnetic shield member 40 and the second coil holding member 30 is not particularly limited, but for example, it is 3 mm or less. Note that, the longer the distance between the first magnetic shield member 40 and the second coil holding member 30 is, the more difficult it is for the heat from the coil component 10 to be dissipated, and there is a risk that the coil component 10 becomes high temperature. For this reason, the distance between the first magnetic shield member 40 and the second coil holding member 30 is preferably 1 mm or less.

[0082] (Second magnetic shield member) The second magnetic shield member 50 is overlapped on the surface of the first magnetic shield member 40 opposite to the surface overlapping the second coil holding member 30. The second magnetic shield member 50 is formed in a plate shape and extends along the radial direction of the planar coil 11. The second magnetic shield member 50 has a size such that, when viewed in the axial direction, its outer peripheral edge is located outside the second coil holding member 30 and the planar coil 11, and outside the first magnetic shield member 40. In the illustrated example, the first magnetic shield member 40 is square when viewed in the axial direction.

[0083] The second magnetic shield member 50 is non-magnetic and has conductivity. Thereby, the second magnetic shield member 50 suppresses magnetic permeation and / or leakage magnetic field. And it is possible to suppress the magnetic or electromagnetic wave generated in the coil component 10 from affecting other electronic components, the human body, etc. As a material for forming the second magnetic shield member 50, for example, metals such as aluminum and aluminum alloy can be adopted.

[0084] (Connection terminal) As shown in FIGS. 2 and 3, the first connection terminal 61 is connected to the radially inner end of the first turn portion 111 located on the innermost circumferential side of the planar coil 11. Although not shown in the figure, the first connection terminal 61 passes between the second coil holding member 30 and the first magnetic shielding member 40 in the radially outward direction and extends from the second coil holding member 30. The second connection terminal 62 is connected to the radially outer end of the eighth turn portion 118 located on the outermost circumferential side of the planar coil 11. The first connection terminal 61 and the second connection terminal 62 can be used, for example, when connecting to the high-frequency current supply unit 1A or the conversion unit 2A.

[0085] When the coil component 10 is used as the power transmission coil, the first connection terminal 61 and the second connection terminal 62 are connected to the high-frequency current supply unit 1A or the AC power supply as shown in FIG. 1. When a high-frequency current is supplied to the coil component 10, the current can flow from the first connection terminal 61 to the planar coil 11 and then from the second connection terminal 62 to the high-frequency current supply unit 1A or the AC power supply. Also, the current can flow from the second connection terminal 62 to the planar coil 11 and then from the first connection terminal 61 to the high-frequency current supply unit 1A or the AC power supply. Thereby, a magnetic field including magnetic force lines along the central axis of the planar coil 11 can be generated.

[0086] On the other hand, when the coil component 10 is used as the power reception coil, a high-frequency current can be generated in the planar coil 11 by receiving a magnetic field including magnetic force lines along the central axis of the planar coil 11. Then, this high-frequency current can be supplied from the first connection terminal 61 or the second connection terminal 62 to an external device.

[0087] The first connection terminal 61 and the second connection terminal 62 are formed of a conductive material, needless to say. In the present embodiment, the first connection terminal 61 and the second connection terminal 62 are formed of copper, which is the same material as the conductor 11E of the planar coil 11, but is not limited thereto. The first connection terminal 61 and the second connection terminal 62 may be formed of a copper alloy, aluminum, an aluminum alloy, or the like.

[0088] <Manufacturing method of coil component> Next, an example of the manufacturing method of the coil component 10 will be described.

[0089] FIG. 6A is a plan view of the mold 100 used in this example, and FIG. 6B is a perspective view of the mold 100. When manufacturing the coil component 10, first, the mold 100 is prepared. The mold 100 has a plate-shaped main body portion 101 and a spiral convex portion 102 protruding from the surface of the main body portion 101. And, one or a plurality (a plurality in this example) of notches 103 that are recessed from the tip of the convex portion 102 are formed in the mold 100. The notch 103 is open from the inner surface 102A of the convex portion 102 located on the central side of the spiral shape formed by the convex portion 102 and the outer surface 102B on the opposite side thereof.

[0090] In this example, the plurality of notches 103 include one or a plurality (a plurality in this example) of notch groups 103G each composed of a plurality of notches 103 arranged in the radial direction. Specifically, in the mold 100, four notch groups 103G are arranged at regular angles (90 degrees in this example) in the circumferential direction.

[0091] The convex portion 102 in the mold 100 includes first to eighth turn groove forming portions 121 to 128. The first to eighth turn groove forming portions 121 to 128 are arranged in this order from the inner position in the radial direction toward the outer side. Each turn groove forming portion 121 to 128 extends on the virtual plane. The first to eighth turn groove forming portions 121 to 128 are connected in this order, thereby forming a spiral shape. In the illustrated example, since the convex portion 102 has a shape along the planar coil 11, it is octagonal as a whole. Each turn groove forming portion 121 to 128 includes a plurality of first straight portions st11 to ninth straight portions st19 arranged around its central axis. The straight portions st11 to st19 each extend linearly when viewed in the axial direction. In each turn groove forming portion 121 to 128, a spiral shape is formed by sequentially connecting the plurality of straight portions st11 to st19 so that one of the adjacent straight portions is bent with respect to the other.

[0092] The notch group 103G is provided at the first straight portions st11, the third straight portions st13, the fifth straight portions st15, and the seventh straight portions st17 in each turn groove forming portion 121 to 128. Further, each notch 103 is formed between both ends of each of the first straight portion st11, the third straight portion st13, the fifth straight portion st15, and the seventh straight portion st17. In other words, the notch 103 is not formed at the bent portion.

[0093] Also, in the mold 100, it is desirable that the notch 103 be formed such that the ratio of the volume of all the notches 103 to the reference volume obtained by adding the volume of the convex portion 102 and the volume of all the notches 103 is less than 10%. In the present embodiment, the notch 103 is formed such that the ratio of the volume of all the notches 103 to the reference volume is less than 10%. Thereby, when the coil component 10 is completed, the volume of the wall portion 32 of the second coil holding member 30 having magnetism is sufficiently ensured, and the effect of improving the coil performance by the wall portion 32 is suitably obtained. However, the number and position of the notches 103 are not particularly limited.

[0094] After the mold 100 as described above is prepared, a spiral planar coil 11 is installed on the surface of the main body portion 101 of the mold 100 along the convex portion 102. FIGS. 6A and 6B show a state in which the planar coil 11 is installed in the mold 100.

[0095] Thereafter, a molten molding material is installed so as to cover the planar coil 11 and the mold 100. In this example, the molding material is supplied to the center side of the mold 100, and the molding material flows outward in the radial direction as shown by the arrow in FIG. 7A. Here, the mold 100 is formed with notches 103 that are recessed from the tip to the convex portion 102. The notch 103 allows the flow of the molding material as shown by the arrow in FIG. 7B. Thereby, the notch 103 ensures good fluidity of the molding material and enables the molding material to be uniformly developed on the mold 100.

[0096] Thereafter, by curing the above-described molding material, an intermediate body 10M is produced, which includes a first coil holding member 20 made of the molding material and a planar coil 11 integrated with the first coil holding member 20. A spiral-shaped groove 21 corresponding to the convex portion 102 is formed in the first coil holding member 20, and at a position corresponding to the notch 103 in the groove 21, a raised portion 22 is formed that partially fills the groove 21 to divide the groove 21 or partially shallow the depth of the groove 21. Here, in the present embodiment, the molding material is uniformly spread on the mold 100 by the notch 103, so that the thickness of the molding material becomes uniform. As a result, the thickness of the first coil holding member 20 can also be uniformly formed.

[0097] After the intermediate body 10M is produced, the intermediate body 10M is removed from the mold 100. Then, a molten magnetic resin material containing a magnetic material and a resin is placed on the intermediate body 10M so as to fill the groove 21 of the first coil holding member 20 and cover the planar coil 11 held by the first coil holding member 20. Then, by curing the magnetic resin material, a second coil holding member 30 is produced. The second coil holding member 30 is formed with a plate-shaped spacer portion 31 extending and expanding in the radial direction, and a spiral-shaped wall portion 32 formed from the filling portion of the magnetic resin material into the groove 21 and protruding from the spacer portion 31. The wall portion 32 has a recess 33 that is recessed toward the spacer portion 31 at a position corresponding to the raised portion 22 of the first coil holding member 20.

[0098] Thereafter, a first connection terminal 61 and a second connection terminal 62 are provided, and the first magnetic shield member 40 and the second magnetic shield member 50 are sequentially stacked on the second coil holding member 30, thereby manufacturing the coil component 10.

[0099] In the present embodiment described above, a first coil holding member 20 for holding the planar coil 11 is created using a mold 100 in which a notch 103 that is recessed from the tip is formed in the spiral-shaped convex portion 102. The notch 103 is formed so as to open from the inner surface 102A of the convex portion 102 located on the central side of the spiral shape formed by the convex portion 102 and the outer surface 102B on the opposite side thereof.

[0100] The notch 103 as described above allows the flow of the molding material. Thereby, the notch 103 ensures good fluidity of the molding material and enables the molding material to be uniformly spread on the mold 100. As a result, the thickness of the molding material on the mold 100 becomes uniform, and the thickness of the first coil holding member 20 can also be formed uniformly. Further, in the first coil holding member 20 formed by curing the molding material, a spiral groove 21 corresponding to the convex portion 102 of the mold 100 is formed, and at a position corresponding to the notch 103 in the groove 21, a raised portion 22 that partially fills the groove 21 to divide the groove or partially shallow the depth of the groove 21 is formed. Here, the raised portion 22 can function as a rib that reinforces the strength and rigidity that can be reduced by the groove 21. Thereby, it becomes difficult for the first coil holding member 20 to bend, and the shape retention performance is improved. Therefore, according to the present embodiment, variations in the thickness and warpage of the coil component 10 can be suppressed.

[0101] <Modification example> Next, a plurality of modification examples of the coil component 10 according to the above-described embodiment will be described with reference to FIGS. 8 to 13, FIGS. 14A and 14B. The same components as those in the above-described embodiment in the modification examples described below are denoted by the same reference numerals, and redundant descriptions are omitted. In FIGS. 8 to 13 and 14A, the illustration of the first coil holding member 20 is omitted.

[0102] FIG. 8 is a plan view of the coil component according to the first modification. In the first modification, the plurality of recesses 33 formed in the wall portion 32 of the second coil holding member 30 include eight recess groups 33G each composed of a plurality of recesses 33 arranged in the radial direction. Specifically, the eight recess groups 33G are formed at regular angles (45 degrees) in the circumferential direction of the spiral shape. Each recess group 33G is formed between both ends of the straight portions st1 to st9. The formation positions of the eight recess groups 33G correspond to the positions of the eight arrows in FIG. 8. The mold used for manufacturing the first modification has the same shape as the second coil holding member 30. The formation pattern of the raised portion 22 in the first coil holding member 20 formed by such a mold is the inversion of the formation pattern of the recess 33.

[0103] FIG. 9 is a plan view of the coil component according to the second modification. In the second modification, the plurality of recesses 33 formed in the wall portion 32 of the second coil holding member 30 include four recess groups 33G each composed of a plurality of recesses 33 arranged in the radial direction. Such four recess groups 33G extending in the radial direction are formed at regular angles (90 degrees) in the circumferential direction of the spiral shape. Further, on both sides of each of the recess groups 33G arranged in the radial direction in the wall portion 32, recess groups 33G arranged parallel to each recess group 33G are formed. That is, in this modification, twelve recess groups 33G are formed. A set of one recess group 33G extending in the radial direction and two recess groups 33G parallel thereto are formed in the first straight portion st1, the third straight portion st3, the fifth straight portion st5, and the seventh straight portion st7, and are formed between both ends of each straight portion. The formation positions of the twelve recess groups 33G correspond to the positions of the twelve arrows in FIG. 9. The mold used for manufacturing the second modification has the same shape as the second coil holding member 30. The formation pattern of the raised portion 22 in the first coil holding member 20 formed by such a mold is the inversion of the formation pattern of the recess 33.

[0104] FIG. 10 is a plan view of a coil component according to a third modification. In the third modification, eight recess groups 33G each consisting of a plurality of radially aligned recesses 33 are included in a plurality of recesses 33 formed in the wall portion 32 of the second coil holding member 30. Such eight radially extending recess groups 33G are formed at regular angles (45 degrees) in the circumferential direction of the spiral shape. Further, on both sides of each of the recess groups 33G aligned radially in the wall portion 32, recess groups 33G parallel to each recess group 33G are formed. That is, in this modification, 24 recess groups 33G are formed. A set of one radially extending recess group 33G and two recess groups 33G parallel thereto are formed in each of the straight portions st1 to st8 and are formed between both ends of each straight portion. The formation positions of the 24 recess groups 33G correspond to the positions of the 24 arrows in FIG. 10. The mold used for manufacturing the third modification has the same shape as the second coil holding member 30. The formation pattern of the raised portions 22 in the first coil holding member 20 formed by such a mold is the reverse of the formation pattern of the recesses 33.

[0105] FIG. 11 is a plan view of a coil component according to a fourth modification. The formation pattern of the plurality of recesses 33 formed in the wall portion 32 of the second coil holding member 30 in the fourth modification is the same as that in the above-described embodiment. That is, the plurality of recesses 33 include four recess groups 33G each consisting of a plurality of radially aligned recesses 33. However, the width of the recesses 33 in the four recess groups 33G is larger than the width of the recesses 33 in the above-described embodiment. The formation positions of the four recess groups 33G correspond to the positions of the four arrows in FIG. 11. The mold used for manufacturing the fourth modification has the same shape as the second coil holding member 30. The formation pattern of the raised portions 22 in the first coil holding member 20 formed by such a mold is the reverse of the formation pattern of the recesses 33.

[0106] FIG. 12 is a plan view of a coil component according to a fifth modification. The formation pattern of the plurality of recesses 33 formed in the wall portion 32 of the second coil holding member 30 in the fifth modification is the same as that in the first modification. That is, the plurality of recesses 33 include eight recess groups 33G each composed of a plurality of recesses 33 arranged in the radial direction. However, the width of the recesses 33 in the eight recess groups 33G is larger than the width of the recesses 33 in the first modification. The formation positions of the eight recess groups 33G correspond to the positions of the eight arrows in FIG. 12. The mold used for manufacturing the fifth modification has the same shape as the second coil holding member 30. The formation pattern of the raised portions 22 in the first coil holding member 20 formed by such a mold is the inversion of the formation pattern of the recesses 33.

[0107] FIG. 13 is a plan view of a coil component according to a sixth modification. In the sixth modification, similar to the first modification, the plurality of recesses 33 formed in the wall portion 32 of the second coil holding member 30 include eight recess groups 33G each composed of a plurality of recesses 33 arranged in the radial direction. And the eight recess groups 33G are formed at regular angles (45 degrees) in the circumferential direction of the spiral shape. However, each of the eight recess groups 33G is formed at the bent portion where adjacent straight portions are connected in the straight portions st1 to st9. The formation positions of the eight recess groups 33G correspond to the positions of the eight arrows in FIG. 8. The mold used for manufacturing the sixth modification has the same shape as the second coil holding member 30. The formation pattern of the raised portions 22 in the first coil holding member 20 formed by such a mold is the inversion of the formation pattern of the recesses 33.

[0108] FIG. 14A is a plan view of a coil component according to a seventh modification. FIG. 14B is a view showing the arrangement of the ferrite plate 40P constituting the first magnetic shield member 40 in the coil component according to the seventh modification.

[0109] In the seventh modification, as shown in FIG. 14B, the first magnetic shield member 40 is configured by laying a plurality of ferrite plates 40P. Then, the second coil holding member 30 is stacked on the first magnetic shield member 40. And the boundary BL between adjacent ferrite plates 40P overlaps with the recess 33 of the wall portion 32 of the second coil holding member 30. The position of the notch in the mold and the shape of the plurality of ferrite plates are adjusted so as to form such an overlapping state.

[0110] In the seventh modification, 12 ferrite plates 40P are laid, and 12 boundaries are formed between adjacent ferrite plates 40P. In the seventh modification, 12 groups of recesses 33G are formed side by side while overlapping on each boundary between 12 pairs of adjacent ferrite plates 40P. The formation positions of the 12 groups of recesses 33G correspond to the positions of the 12 arrows in FIG. 14A. The mold used for manufacturing the seventh modification has the same shape as the second coil holding member 30. The formation pattern of the protrusion 22 in the first coil holding member 20 formed by such a mold is the inversion of the formation pattern of the recess 33.

[0111] <Performance Evaluation Simulation> Next, the evaluation results of evaluating the performance of the coil component 10 according to the above-described embodiment and the coil components according to a plurality of modifications by simulation will be described. In the performance evaluation described here, the Q value of each coil component was calculated by simulation.

[0112] FIG. 15 shows a graph for explaining the performance evaluation results of the embodiment and a plurality of modification examples. The volume of the wall portion 32 of the second coil holding member 30, in other words, the volume of the groove 21 of the first coil holding member 20, becomes smaller in the order of the embodiment, the first modification example, the sixth modification example, the seventh modification example, the second modification example, the third modification example, the fourth modification example, and the fifth modification example, which have the same volume. On the horizontal axis (groove volume ratio) in FIG. 15, 100% indicates a configuration (ref) in which the raised portion 22 is not formed in the groove 21. The volume of the groove 21 of the embodiment and each modification example is smaller than that of the configuration (ref) in which the raised portion 22 is not formed in the groove 21. The horizontal axis (groove volume ratio) indicates the ratio of the volume of the groove 21 of the embodiment and each modification example to the volume of the groove 21 of the configuration (ref) in which the raised portion 22 is not formed in the groove 21. The larger the groove volume ratio, the larger the volume of the wall portion 32 means.

[0113] Table 1 below shows the relationship between the above-mentioned ref, the volume ratios of the embodiment and each modification example, and the Q value.

[0114]

Table 1

[0115] Referring to FIG. 15 and Table 1, in the first modification example, the sixth modification example, the seventh modification example, the second modification example, and the third modification example with a groove volume ratio of 90% or more, a large volume of the wall portion 32 is ensured, so that a high Q value can be maintained. In the mold 100, it is desirable that the notch 103 is formed so that the ratio of the notch portion volume to the reference volume obtained by adding the volume of the convex portion 102 and the notch portion volume of all the notches 103 is less than 10%. This means that the groove volume ratio becomes 90% or more, and it means that the volume of the wall portion 32 becomes 90% or more compared to the case where there is no recess 33. The results shown in FIG. 15 and Table 1 support that the above-described formation conditions for the notch 103 are desirable conditions.

[0116] Comparing the first modification example with the sixth modification example, although the groove volume ratio is the same, the Q value of the sixth modification example is lower than that of the first modification example. Considering this result, it is considered undesirable to form the recess 33 in the bent portion. Also, for the seventh modification example, no noticeable performance change is observed with respect to other similar conditions (the second modification example, the sixth modification example, etc.). Considering this result, the positional relationship between the boundary of the recess 33 and the ferrite plate 40P is considered to be irrelevant to the performance change.

[0117] As described above, the embodiments of the present disclosure have been explained, but various modifications may be added to the above-described embodiments. Such modification examples may also be included in the technical scope of the present disclosure. For example, in the above-described embodiment, the raised portion 22 of the first coil holding member 20 partially fills the groove 21 and divides the groove 21, but the raised portion 22 may partially shallower the depth of the groove 21. In this case, the notch 103 formed in the convex portion 102 of the mold 100 is formed such that the bottom surface does not reach the starting point of the convex portion 102 and is recessed halfway along the convex portion 102.

Description of Reference Numerals

[0118] S… Power transmission system 1… Power transmission device 1A… High-frequency current supply unit 2… Power receiving device 2A… Conversion unit 10… Coil component 10M… Intermediate body 11… Planar coil 11E… Conductor 11n… Turn portion 111… First turn portion 112… Second turn portion 113… Third turn portion 114… Fourth turn portion 115… Fifth turn portion 116… Sixth turn portion 117… Seventh turn portion 118… Eighth turn portion st1~st9… Straight portion st1… First straight portion st2… Second straight portion st3…The 3rd straight part st4…The 4th straight part st5…The 5th straight part st6…The 6th straight part st7…The 7th straight part st8…The 8th straight part st9…The 9th straight part 20…The 1st coil holding member 21…Groove 22…Raised part 22G…Group of raised parts 30…The 2nd coil holding member 31…Spacer part 32…Wall part 33…Recessed part 33G…Group of recessed parts 40…The 1st magnetic shield member 40P…Ferrite plate 50…The 2nd magnetic shield member 61…The 1st connection terminal 62…The 2nd connection terminal 100…Mold 101…Body part 102…Protrusion 102A…Inner surface 102B…Outer surface 103…Notch 103G…Group of notches C…Central axis

Claims

1. Preparing a mold having a plate-shaped body portion and a spiral convex portion protruding from the surface of the body portion, with a recess at the tip of the convex portion, and one or more notches formed that open from the inner surface of the convex portion located on the central side of the spiral shape formed by the convex portion and the outer surface on the opposite side thereof; Installing a spiral planar coil on the surface of the body portion of the mold along the convex portion; Installing a molten molding material so as to cover the planar coil and the mold; A first coil holding member in which, by curing the molding material, a spiral groove corresponding to the convex portion is formed, and at a position corresponding to the notch in the groove, a raised portion is formed that partially fills the groove to divide the groove or partially shallows the depth of the groove, and a step of producing an intermediate body composed of the first coil holding member and the planar coil integrated with the first coil holding member. A method for manufacturing a coil component.

2. A plurality of the notches are formed in the mold; The method for manufacturing a coil component according to claim 1, wherein the plurality of notches include one or more notch groups composed of a plurality of the notches arranged in the radial direction of the spiral shape formed by the convex portion or in a direction parallel to the radial direction.

3. The method for manufacturing a coil component according to claim 2, wherein the plurality of notches include a plurality of notch groups arranged at regular angles in the circumferential direction around the center of the spiral shape formed by the convex portion, and each of the notch groups is arranged in the radial direction.

4. When viewed in the axial direction of the spiral shape formed by the convex portion, the convex portion includes a plurality of linearly extending straight portions, and the plurality of straight portions are sequentially connected so that one of the adjacent straight portions is bent with respect to the other to form a spiral shape. The method for manufacturing a coil component according to claim 1, wherein the notch is formed between both ends of the straight portion.

5. The method for manufacturing a coil component according to claim 1, wherein the mold is used in which the ratio of the volume of all the notches to the reference volume obtained by summing the volume of the convex portion and the volume of all the notches is less than 10%.

6. A step of installing a molten magnetic resin material containing a magnetic body and a resin on the intermediate body so as to fill the groove of the first coil holding member and cover the planar coil held by the first coil holding member. By curing the magnetic resin material, a plate-like spacer portion extending and expanding in the radial direction of the spiral shape formed by the planar coil, and a spiral wall portion formed from the filling portion of the magnetic resin material into the groove and protruding from the spacer portion are produced. The method for manufacturing a coil component according to any one of claims 1 to 5, wherein a recess recessed toward the spacer portion side is formed at a position corresponding to the raised portion of the first coil holding member in the wall portion.

7. The method further includes a step of overlapping a second coil holding member on a magnetic shield member configured by laying a plurality of ferrite plates. The method for manufacturing a coil component according to claim 6, wherein the position of the notch and the shapes of the plurality of ferrite plates in the mold are adjusted so that the boundary between adjacent ferrite plates overlaps with the recess in the wall portion.

8. A first coil holding member in which a spiral groove is formed and a raised portion that partially fills and divides the groove or partially shallows the depth of the groove is formed. A planar coil having a spiral shape disposed in a portion of the first coil holding member where there is no groove and extending along the groove. A second coil holding member including a plate-like spacer portion and a spiral wall portion protruding from the spacer portion, and sandwiching the planar coil between the second coil holding member and the first coil holding member. The wall portion passes through the planar coil and is accommodated in the groove. The wall portion has a recess recessed toward the spacer portion side at a position corresponding to the raised portion. A coil component.

9. A first coil holding member in which a spiral groove is formed and a raised portion that partially fills and divides the groove or shallows the depth of the groove is formed. A coil component intermediate body, comprising a planar coil having a spiral shape disposed in a portion of the first coil holding member where there is no groove and extending along the groove.

10. A power transmission device including the coil component according to claim 8.

11. A power receiving device including the coil component according to claim 8.

12. A power transmission device and a power receiving device are provided. A power transmission system, wherein at least one of the power transmission device and the power receiving device includes the coil component according to claim 8.

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