Coil component, power transmitting device, power receiving device, power transmitting system, movable body, and method for manufacturing coil component

Abstract

To reduce the possibility that the intensity of a coil component may be reduced, and facilitate manufacture of the coil component having a magnetic substance wall.SOLUTION: A coil component includes a planar coil 11, a first holding member 20, and a second holding member 30. The first holding member 20 holds the planar coil 11. The second holding member 30 sandwiches the planar coil 11 with the first holding member 20 to be integrated with the planar coil 11 and the first holding member 20. The first holding member 20 has a contact surface 20S1 in contact with a first surface 11A of the planar coil 11. The contact surface 20S1 has a groove 24 formed. The second holding member 30 has a base part 31 and a wall part 32. The wall part 32 extends into the groove 24 of the first holding member 20 from the base part 31 through between adjacent turn parts of the planar coil 11. The width of a bottom part 24a of the groove 24 is smaller than the width at a height position of the contact surface 20S1 of the groove 24.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a coil component, a power transmitting device, a power receiving device, a power transfer system, a moving body, and a method for manufacturing a coil component. [Background technology]

[0002] In recent years, wireless power transmission systems that transmit power contactlessly from a power transmission device to a power receiving device have become widespread. Patent Document 1 discloses a coil component used in a power transmission device and a power receiving device of a wireless power transmission system. The coil component includes a coil formed in a spiral shape. When power is supplied to the coil of the power transmission device, a magnetic field is generated in the coil. Due to the influence of this magnetic field, a current flows in the coil of the power receiving device. In general, the coil is used while being housed in a hollow case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-88728 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such a wireless power transmission system, it is desirable to improve the performance of the coil components to perform efficient power transmission. Patent Document 1 discusses improving the performance of the coil components by providing a magnetic wall between adjacent turns of the coil.

[0005] Also, it has been considered to form the case integrally with the coil and to have the case hold the coil. In other words, it has been considered to form the case as a holding member that holds the coil. In this case, the inner surface of the holding member has a shape corresponding to the shape of the coil and other parts associated with the coil. For example, when the wall of the magnetic body described above extends from the coil, it is necessary to form a groove that accommodates this wall on the inner surface of the holding member.

[0006] In order to improve the performance of the coil component, it is desirable to increase the height of the magnetic wall. In this case, it is necessary to deepen the grooves in the holding member. However, if the grooves in the holding member are deepened, the thickness of the portion of the holding member where the grooves are formed will become thinner, and there is a concern that the strength of the holding member (and therefore the strength of the coil component) will decrease. In addition, there is a concern that if the grooves in the holding member are deepened, it will become difficult to mold the holding member, and therefore the manufacturing of the coil component will become difficult.

[0007] An embodiment of the present disclosure aims to suppress the possibility that the strength of a coil component may be reduced due to the formation of a magnetic wall, and to facilitate the manufacture of a coil component having a magnetic wall. [Means for solving the problem]

[0008] One embodiment of the present disclosure relates to the following [1] to

[22] .

[0009] [1] a planar coil having a spiral shape and including a first side and a second side opposite the first side; a first holding member that overlaps the planar coil so as to face the first surface and holds the planar coil; a second holding member that sandwiches the planar coil between the first holding member and the second holding member, the planar coil includes a plurality of turn portions arranged in a coil radial direction, which is a radial direction of the planar coil, the first holding member has a contact surface that contacts the first surface, a groove is formed on the contact surface, the groove extending between adjacent turn portions of the planar coil as viewed in a coil axis direction that is an axial direction of the planar coil; the second holding member has a base portion in contact with the second surface of the planar coil, and a wall portion extending from the base portion into the groove of the first holding member through spaces between adjacent turn portions of the planar coil, A coil component, wherein a width of the bottom of the groove is narrower than a width of the groove at a height position of the contact surface.

[0010] [2] a surface of the first holding member that defines the groove has a pair of groove side surfaces that face each other in the coil radial direction, The coil component according to [1], wherein at least one of the pair of groove side surfaces has an inclined surface that is inclined with respect to the coil axis direction.

[0011] [3] The coil component according to [2], wherein one of the pair of groove side surfaces, which is located on the outer side in the coil radial direction, has an inclined surface that is inclined with respect to the coil axial direction.

[0012] [4] The coil component according to [2], wherein one of the pair of groove side surfaces, which is located on the inner side in the coil radial direction, has an inclined surface that is inclined with respect to the coil axial direction.

[0013] [5] The coil component according to [2], wherein each of the pair of groove side surfaces has an inclined surface that is inclined with respect to the coil axis direction.

[0014] [6] the wall portion has a base end portion extending from the base portion along the coil axis direction with a uniform width, The coil component according to any one of [1] to [5], wherein a dimension of the base end along the coil axis direction is larger than a thickness of the planar coil.

[0015] [7] The coil unit according to any one of [1] to [6], wherein the distance between the top of the groove and the contact surface is 2 mm or more.

[0016] [8] The coil component according to any one of [1] to [7], wherein the width of the bottom of the groove is equal to or less than half the width of the groove at a height position of the contact surface.

[0017] [9] The coil component according to any one of [1] to [8], wherein the first holding member includes a fiber.

[0018]

[10] The coil component according to any one of [1] to [9], wherein the first holding member is nonmagnetic and insulating.

[0019]

[11] The coil component according to any one of [1] to

[10] , wherein the second holding member is magnetic.

[0020]

[12] The coil component according to any one of [1] to

[11] , wherein the planar coil is formed into a plate shape.

[0021]

[13] A power transmitting device comprising the coil component according to any one of [1] to

[12] .

[0022]

[14] A power receiving device comprising the coil component according to any one of [1] to

[12] .

[0023]

[15] The power transmission device and the power receiving device are provided. A power transfer system, wherein at least one of the power transmitting device and the power receiving device includes the coil component according to any one of [1] to

[12] .

[0024]

[16] A moving body comprising the coil component according to any one of [1] to

[12] .

[0025]

[17] A method for producing a coil component according to any one of [1] to

[12] , A step of preparing a mold having a main body and a spiral-shaped protrusion extending from the main body; a step of disposing a spiral-shaped planar coil corresponding to the spiral shape of the protrusion on the main body of the mold such that the protrusion extends between adjacent turn portions of the planar coil; a step of pressing a material for producing a first holding member against a die in which the planar coil is disposed to form a first holding member, thereby producing a coil intermediate material in which the first holding member and the planar coil are integrated; removing the die from the coil intermediate material; a step of forming a second holder covering the planar coil on the coil intermediate material after removing the die from the coil intermediate material; Equipped with The manufacturing method, wherein the width of the top of the convex portion of the mold is narrower than the width of the convex portion at a connection position with the main body portion.

[0026]

[18] The protrusion has a pair of die side surfaces facing each other in a die radial direction, which is a radial direction of the protrusion, The manufacturing method described in

[17] , wherein at least one of the pair of mold side surfaces has an inclined surface that is inclined with respect to the mold axis direction, which is the axial direction of the convex portion.

[0027]

[19] The manufacturing method described in

[18] , wherein the mold side surface located radially outward of the pair of mold side surfaces has an inclined surface inclined with respect to the mold axial direction.

[0028]

[20] The manufacturing method described in

[18] , wherein one of the pair of mold side surfaces, which is located radially inward in the mold direction, has an inclined surface inclined with respect to the mold axial direction.

[0029] [twenty one] The manufacturing method described in

[18] , wherein each of the pair of mold side surfaces has an inclined surface inclined with respect to the mold axial direction.

[0030] [twenty two] The manufacturing method according to any one of

[17] to

[21] , wherein the width of the top of the protrusion is half or less of the width of the protrusion at the connection position with the main body. Effect of the Invention

[0031] According to an embodiment of the present disclosure, it is possible to suppress the risk of the strength of the coil component being reduced due to the formation of a magnetic wall, and it is also possible to facilitate the manufacture of a coil component having a magnetic wall. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a diagram illustrating a schematic diagram of a wireless power transmission system to which a coil unit according to an embodiment can be applied. [Diagram 2] FIG. 2 is an exploded perspective view of the coil component according to the embodiment. [Diagram 3] FIG. 3 is a cross-sectional view of the coil component shown in FIG. 2 taken along the coil axis direction. [Figure 4] FIG. 4 is a plan view of a coil intermediate material of the coil device shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view illustrating an example of a method for manufacturing the coil component shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view illustrating an example of a method for manufacturing the coil component shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view for explaining an example of a method for manufacturing the coil component shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view for explaining an example of a method for manufacturing the coil component shown in FIG. [Figure 9] FIG. 9 is a diagram corresponding to the partially enlarged view of FIG. 3, and is a diagram for explaining a modified example of the coil component. [Figure 10]FIG. 10 is a diagram corresponding to the partially enlarged view of FIG. 3, and is a diagram for explaining another modified example of the coil component. [Figure 11] FIG. 11 is a diagram corresponding to the partially enlarged view of FIG. 3, and is a diagram for explaining still another modified example of the coil component. [Figure 12] FIG. 12 is a diagram corresponding to the partially enlarged view of FIG. 3, and is a diagram for explaining still another modified example of the coil component. [Figure 13] FIG. 13 is a diagram corresponding to the partially enlarged view of FIG. 3, and is a diagram for explaining still another modified example of the coil component. [Figure 14] FIG. 14 is a table showing the results of the simulation. [Figure 15] FIG. 15 is a graph showing the results of the simulation. [Figure 16] FIG. 16 is a view corresponding to the partially enlarged view of FIG. 3, and is a partially enlarged cross-sectional view of a coil component in which the width of the wall portion is uniform along the coil axial direction. [Figure 17] FIG. 17 corresponds to FIG. 5 and is a diagram for explaining a method of manufacturing the coil component shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, each embodiment will be described with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and understanding.

[0034] In addition, in this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely on the basis of differences in name. Thus, for example, "sheet" is a concept that includes members that may also be called films and plates.

[0035] <Wireless power transmission system> Fig. 1 shows a schematic diagram of a wireless power transmission system S to which a coil component 10 according to an embodiment is applied. First, the wireless power transmission system S (hereinafter, abbreviated as power transmission system S) will be described with reference to Fig. 1. It goes without saying that a coil component different from the coil component 10 according to the present embodiment can be applied to the power transmission system S.

[0036] <Wireless power transmission system> The power transfer system S includes a power transmitting device 1 and a power receiving device 2. The power transmitting device 1 includes a coil component 10 and a high-frequency current supplying unit 1A. The coil component 10 in the power transmitting device 1 functions as a power transmitting coil component. The high-frequency current supplying unit 1A supplies a high-frequency current to the coil component 10 serving as a power transmitting coil component.

[0037] The power receiving device 2 includes a coil component 10 and a conversion unit 2A. The coil component 10 in the power receiving device 2 functions as a power receiving coil component. The conversion unit 2A shapes a high-frequency current generated in the coil component 10. The conversion unit 2A includes a rectifier circuit that converts the high-frequency current into a direct current, and the like. The conversion unit 2A may include, for example, a full-wave rectifier circuit including a plurality of diodes and a smoothing capacitor.

[0038] In this embodiment, each of the power transmitting device 1 and the power receiving device 2 includes a coil component 10. However, the coil component 10 may be used in only one of the power transmitting device 1 and the power receiving device 2, and a different type of coil component may be used in the other.

[0039] When transmitting power wirelessly (contactlessly) from the power transmitting device 1 to the power receiving device 2, the power transmitting device 1 supplies a high-frequency current of a predetermined frequency from the high-frequency current supply unit 1A to the coil component 10 serving as a power transmitting coil component. 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 serving as a power receiving coil component in the power receiving device 2. That is, the power receiving device 2 receives the magnetic field from the power transmitting device 1 or is influenced by the magnetic field, and causes the high-frequency current to flow by 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.

[0040] The power transmission system S shown in Fig. 1 employs a magnetic resonance method as a power transmission method. However, the coil component 10 according to the present embodiment may be used in a power transmission system that employs an electromagnetic induction method. The power transmission system S is configured as a system that wirelessly transmits power to an electric vehicle. In this case, the power transmitting device 1 is installed on a road, a parking lot, or the like. The power receiving device 2 is installed in the electric vehicle.

[0041] However, the use of the power transmission system S is not limited to power transmission to electric vehicles. For example, the power transmission system S may be used to transmit power to flying objects such as drones and robots. The power transmission system S may also be used to transmit power to submersibles and exploration robots in the sea. In this way, the power transmission system S can be used to transmit power to various moving objects such as electric vehicles, flying objects, robots, and submersibles. The use of the coil component 10 is not limited to wireless power transmission systems. For example, the coil component 10 may be used in transformers, DC-DC converters, antennas, and the like.

[0042] <Coil parts> The coil device 10 will be described below. Fig. 2 is an exploded perspective view of the coil device 10. Fig. 3 is a cross-sectional view of the coil device 10 taken along a central axis C10 of a planar coil 11, which will be described later. Fig. 4 is a plan view of a coil intermediate material 10M, which will be described later. Note that hatching in the partially enlarged view of Fig. 4 is added to facilitate identification of components of the coil intermediate material 10M, and does not indicate a cross-section of the components of the coil intermediate material 10M.

[0043] As shown in Figs. 2 and 3, the coil component 10 includes a planar coil 11, a first holding member 20, and a second holding member 30. In the illustrated example, the coil component 10 further includes a first magnetic shield member 40, a second magnetic shield member 50, a first connection terminal 61, and a second connection terminal 62. The first holding member 20, the planar coil 11, the second holding member 30, the first magnetic shield member 40, and the second magnetic shield member 50 are stacked in this order. The first connection terminal 61 and the second connection terminal 62 are simply indicated by two-dot chain lines in Fig. 2. As will be described later, the planar coil 11 and the first holding member 20 form a coil intermediate material 10M shown in Fig. 4. Each part of the coil component 10 will be described in detail below.

[0044] (Planar coil) The planar coil 11 has a spiral shape and is made of a conductive material. In the present embodiment, the planar coil 11 includes copper. Specifically, the planar coil 11 is made of copper. However, the planar coil 11 may be made of a copper alloy, aluminum, an aluminum alloy, or the like.

[0045] As shown in FIG. 2, planar coil 11 is plate-shaped, and as shown in FIG. 3, the cross-sectional shape of planar coil 11 in the direction in which planar coil 11 winds in a spiral shape, in other words, in a direction perpendicular to the direction in which it extends in a spiral shape, is rectangular.

[0046] The reference symbol C10 shown in FIG. 2 to FIG. 4 indicates a central axis (hereinafter also referred to as "coil central axis C10") passing through the center of the spiral shape of the planar coil 11. Hereinafter, the axial direction (hereinafter also referred to as "coil axial direction") of the planar coil 11 means a direction extending on the coil central axis C10 or a direction parallel to the coil central axis C10. In addition, the radial direction (hereinafter also referred to as "coil radial direction") of the planar coil 11 means a radial direction of a circle drawn on a plane perpendicular to the coil central axis C10 with an arbitrary point on the coil central axis C10 as a center. The planar coil 11 includes a first surface 11A and a second surface 11B. The first surface 11A faces the first holding member 20. The second surface 11B is a surface opposite to the first surface 11A and faces the second holding member 30.

[0047] As shown in Fig. 2, the planar coil 11 has a conductor 11E having a spiral shape formed by a plurality of turn portions 11n. The plurality of turn portions 11n of the planar coil 11 are arranged in a direction perpendicular to the coil central axis C10. More specifically, the plurality of turn portions 11n are connected so as to gradually move away from the coil central axis C10 in a radially outward direction of the coil. This forms a spiral shape.

[0048] The turn portion 11n is basically a shape in which a linear conductor portion does not form a loop but goes around the coil central axis C10 360 degrees. In the case of a so-called planar coil, both ends of the turn portion 11n are offset in the coil radial direction. In the case of multiple turn portions 11n, an outer end of one turn portion 11n in the coil radial direction is connected to an inner end of another turn portion 11n in the coil radial direction, and the other turn portions 11n extend away from the coil central axis C10.

[0049] Hereinafter, the turn portion 11n that is closest to the coil central axis C10 may be referred to as the turn portion 1101. Also, the turn portion connected to the turn portion 1101 may be referred to as the turn portion 1102. In this embodiment, the turn portions 11n include twelve turn portions 1101 to 1112. Hereinafter, when describing matters common to each of the turn portions 11n, they will basically be referred to as the turn portion 11n.

[0050] In this embodiment, the turn section 11n goes around to form an octagonal shape. More specifically, the turn section 11n goes around to form a regular octagonal shape. However, the turn section 11n may go around to form a polygonal shape other than an octagonal shape. For example, the turn section 11n may go around to form a dodecagonal shape or a regular dodecagonal shape. The turn section 11n may go around to form a circular shape. Note that the spiral shape referred to in this specification and this disclosure means a planar curve shape wound in a spiral shape. The planar curve here includes a planar pattern that repeatedly goes around while bending in a broken line shape as shown in the figure. In other words, the spiral shape means a planar curve shape that moves away from the center as it turns (or approaches the center as it turns).

[0051] An inner end in the coil radial direction of the turn portion 1101 closest to the coil central axis C10 (the end closest to the coil central axis C10) is electrically connected to the second connection terminal 62. On the other hand, an outer end in the coil radial direction of the turn portion 1112 that is the furthest from the coil central axis C10 among the multiple turn portions 11n (the end away from the coil central axis C10) is connected to the first connection terminal 61.

[0052] Here, the inward radial direction (coil radial direction) of the planar coil 11 (turn portion 11n) means a direction approaching the coil central axis C10 in the radial direction. The outward radial direction (coil radial direction) of the planar coil 11 (turn portion 11n) means a direction moving away from the coil central axis C10 in the radial direction. In the present embodiment, the coil central axis C10 is determined as follows. First, from the inner end of the turn portion 1102 adjacent to the innermost turn portion 1101 in the coil radial direction, linear virtual turn portions having a shape similar to that of the turn portion 1102 are drawn in order to form a spiral shape inward in the radial direction. Then, drawing is continued until a virtual turn portion that fits within a diameter of 1 cm can be drawn. Then, a line that passes through the inner region in the coil radial direction of the virtual turn portion that fits within a diameter of 1 cm in a direction perpendicular to the circumferential and radial directions of the spiral shape is determined as the coil central axis C10.

[0053] The planar coil 11 described above is formed, for example, by punching a metal plate such as a copper plate or an aluminum plate into a spiral shape. Alternatively, 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.

[0054] The thickness of the planar coil 11 (thickness of the conductor 11E) may be, for example, 0.1 mm or more and 1.0 mm or less. The radius of the planar coil 11 (the distance from the coil central axis C10 to the part farthest in the radial direction) may be 80 mm or more, or 80 mm or more and 450 mm or less. The aspect ratio of the planar coil 11 (conductor 11E) having a rectangular cross-sectional shape is determined by dividing the coil radial width (width in the coil radial direction) of the planar coil 11 (conductor 11E) 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 3 or more and 10 or less.

[0055] When transmitting power to an electric vehicle using the magnetic resonance method, it is desirable to be able to transmit power of 1 kW or more, preferably 5 kW or more, in a high-frequency current frequency band of 10 kHz to 200 kHz, particularly 75 kHz to 100 kHz, and further 79 kHz to 90 kHz. In this case, the thickness of the planar coil 11 made of copper is preferably 0.2 mm or more. From this perspective, the lower limit of the thickness of the planar coil 11 may be set to 0.2 mm. Furthermore, when transmitting power to an electric vehicle, it is not desirable for the size to be excessively large, and the size may be limited. From this perspective, it is preferable that the planar coil 11 (conductor 11E) is formed to a size that fits within a square with one side of 800 mm.

[0056] Moreover, the line width of the planar coil 11 (line width of the conductor 11E), i.e., the width in the coil radial direction of each turn portion 11n (width in the coil radial direction) 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 high-frequency current frequency band of, for example, 79 kHz to 90 kHz, the coil radial direction width of the turn portion 11n may be 2 mm or more and 20 mm or less, 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. Moreover, the number of turns of the planar coil 11 is not particularly limited, and may be 11 or less, or 13 or more.

[0057] (First holding member) The first holding member 20 overlaps the planar coil 11 so as to face the first surface 11A of the planar coil 11, and holds the planar coil 11. In the coil device 10, for example, when transmitting power, the magnetic field generated in the planar coil 11 passes through the first holding member 20. Therefore, the first holding member 20 is preferably non-conductive (insulating) and non-magnetic so as not to interfere with the magnetic field and to prevent eddy currents from being generated.

[0058] Considering that it is preferable that the first holding member 20 is non-conductive (insulating) and non-magnetic, the material of the first holding member 20 is, for example, a resin, and may be a fiber-reinforced plastic. More specifically, the material of the first holding member 20 may be a glass fiber-reinforced polyamide. However, the material of the first holding member 20 is not particularly limited. For example, it may not contain glass fiber. Also, a thermoplastic resin or a thermosetting resin other than polyamide may be used. Note that insulating is defined as a material having a volume resistivity of 10 10 It means that the material has a resistance of Ω·m or more. Non-magnetic means that it does not exhibit magnetism.

[0059] First holding member 20 is integrated with planar coil 11 to hold planar coil 11. In this embodiment, after planar coil 11 is placed in first holding member forming dies 201, 202 (see FIG. 5) (see FIG. 6), material 220 for making first holding member is pressed into the dies 201, 202 by hot pressing to form (see FIG. 7), and then cooled and solidified to integrate planar coil 11 and first holding member 20. In this specification, first holding member 20 integrated with planar coil 11 is also referred to as coil intermediate material 10M.

[0060] In this embodiment, the first holding member 20 sandwiches the planar coil 11 with the second holding member 30. In the illustrated example, the first holding member 20 has a first contact surface 20S1 that contacts the first surface 11A of the planar coil 11 and a second contact surface 20S2 that contacts a base 31 of the second holding member 30, which will be described later. The height position (position in the coil axis direction) of the first contact surface 20S1 is the same as the height position of the first surface 11A of the planar coil 11. The height position (position in the coil axis direction) of the second contact surface 20S2 is the same as the height position of the second surface 11B of the planar coil 11. The contact surfaces 20S1 and 20S2 form a part of the inner surface of the first holding member 20. The first holding member 20 also has an outer surface 20S3 that is the surface opposite to the contact surfaces 20S1 and 20S2.

[0061] 4 and 5, a groove 24 for receiving a wall portion 32 of a second holding member 30 (described later) is formed in the first holding member 20. The groove 24 will be described in detail later.

[0062] In the illustrated example, a part of the first holding member 20 forms a covering portion 28 that covers the side surface of each turn portion 11n of the planar coil 11. The covering portion 28 is a portion of the first holding member 20 between the first contact surface 20S1 and the second contact surface 20S2. The covering portion 28 extends from the first contact surface 20S1 in the coil axis direction on both sides of the opening 24b of the groove 24. The covering portion 28 forms the second contact surface 20S2. The space surrounded by the covering portion 28 is in communication with the internal space of the groove 24.

[0063] (Second holding member) 3, second holding member 30 in the present embodiment sandwiches planar coil 11 with first holding member 20. In the illustrated example, second holding member 30 is integrated with planar coil 11 and first holding member 20.

[0064] In detail, the second holding member 30 has a base 31 interposed between the planar coil 11 and the first magnetic shield member 40, and a wall portion 32 protruding from the base 31 toward the first holding member 20 in the coil axial direction. The base 31 faces the second surface 11B of the planar coil 11. The base 31 entirely covers the second surface 11B of the planar coil 11. When viewed in the axial direction of the planar coil 11, the base 31 is formed to a size that encompasses the entire planar coil 11. The base 31 and the first holding member 20 sandwich the planar coil 11 therebetween. In the illustrated example, the base 31 contacts the second surface 11B of the planar coil 11. However, another layer may be disposed between the base 31 and the second surface 11B of the planar coil 11.

[0065] The wall portion 32 extends between adjacent turn portions of the planar coil 11. Thus, the wall portion 32 is formed along the spiral-shaped planar coil 11. In the illustrated example, the wall portion 32 is formed in a spiral shape corresponding to the spiral shape of the planar coil 11. As described above, the wall portion 32 is received in the groove 24 of the first holding member 20. In other words, the wall portion 32 fills the groove 24 in the first holding member 20.

[0066] The second holding member 30 is magnetic as a whole. That is, the base 31 and the wall 32 are each magnetic. The second holding member 30 suppresses eddy current loss and leakage flux by magnetism, and increases the coupling coefficient, thereby improving coil performance. The relative permeability of the second holding member 30 is preferably 2.0 or more, and may be 2.0 or more and 10.0 or less. The relative permeability of the second holding member 30 is more preferably 5.0 or more, and may be 5.0 or more and 10.0 or less. The relative permeability of the second holding member 30 is not particularly limited, but if it is too large, the flexibility and strength of the second holding member 30 may be undesirably impaired. Therefore, the relative permeability of the second holding member 30 may be 200 or less.

[0067] Furthermore, the second holding member 30 includes the wall portion 32, which can effectively improve the coil performance. The height 32H of the wall portion 32 (the distance between the top 32a of the wall portion 32 and the second surface 11B of the planar coil 11 along the axial direction of the planar coil 11) is not particularly limited, and may be, for example, 0.5 mm or more, or 1.0 mm or more. The higher the height 32H of the wall portion 32, more specifically, the higher the protruding height 32Ha of the wall portion 32 from the planar coil 11, the higher the effect of suppressing eddy current loss and the higher the coupling coefficient tend to be. On the other hand, the higher the wall portion 32, the more likely it is to be broken starting from its base. Therefore, the protruding height 32Ha of the wall portion 32 may be, for example, 10 mm or less. The protruding height 32Ha of the wall portion 32 from the planar coil 11 is the distance between the top 32a of the wall portion 32 and the first surface 11A. The wall portion 32 will be described in more detail later.

[0068] The second holding member 30 in the present embodiment includes, for example, a resin and a plurality or an infinite number of magnetic particles made of a magnetic material. The magnetic particles are held by the resin as a holding material.

[0069] The magnetic particles may be made of any one or more of ferrite, particularly soft magnetic ferrite, nanocrystalline magnetic material, silicon steel, soft magnetic iron, and amorphous metal. The resin as the holding material may be glass fiber reinforced polyamide. That is, the resin may be made of a material containing polyamide as a thermoplastic resin (thermoplastic material) and glass fiber. However, the molding material of the second holding member 30 is not particularly limited.

[0070] (First magnetic shield member) The first magnetic shield member 40 is provided to suppress magnetic transmission and / or leakage magnetic field. The first magnetic shield member 40 is a sheet-like member separate from the planar coil 11, the first holding member 20, and the second holding member 30. The first magnetic shield member 40 being separate from the planar coil 11, the first holding member 20, and the second holding member 30 means that the first magnetic shield member 40 is not integrated with the planar coil 11, the first holding member 20, and the second holding member 30. However, the first magnetic shield member 40 and the second holding member 30 may be joined via an adhesive layer or the like. The first magnetic shield member 40 is formed to a size that includes the planar coil 11 and the second holding member 30 in a plan view. The first magnetic shield member 40 overlaps the planar coil 11 and the second holding member 30. The first magnetic shield member 40 may be in direct contact with the second holding member 30. Alternatively, between the first magnetic shield member 40 and the second holding member 30, another layer formed of a heat dissipation material or the like may be disposed.

[0071] The first magnetic shield member 40 in this embodiment has magnetism and includes or is made of a magnetic material. In the coil component 10, a magnetic field is generated when a current is supplied to the planar coil 11. The magnetic field generated in such a coil component 10 is generated so as to spread in all directions with respect to the coil central axis C10. At this time, the first magnetic shield member 40 has magnetism, so that the spreading magnetic flux lines can be oriented toward the coil central axis C10. In addition, the coil component 10 may be installed in a vehicle, and in this case, if the magnetic field generated by the coil component 10 flows toward other vehicle components, the vehicle components may be adversely affected. In such a case, the first magnetic shield member 40 can suppress the leakage magnetic field that does not contribute to the generation of current.

[0072] The first magnetic shield member 40 preferably includes a soft magnetic material or a nanocrystalline magnetic material. More specifically, the first magnetic shield member 40 includes a ferrite, preferably a soft ferrite.

[0073] The relative permeability of the first magnetic shield member 40 may be equal to or greater than 500, or equal to or greater than 1000. The relative permeability of the first magnetic shield member 40 may be equal to or greater than 500 and equal to or less than 3000, or equal to or greater than 1000 and equal to or less than 3000. Note that the relative permeability in this specification is a value measured at a frequency of 85 kHz and an environmental temperature of 23 degrees.

[0074] (Second magnetic shield member) The second magnetic shield member 50 is provided so as to cover the first magnetic shield member 40. The second magnetic shield member 50 may be in direct contact with the first magnetic shield member 40. Alternatively, another layer formed of a heat dissipation material or a spacer may be disposed between the second magnetic shield member 50 and the first magnetic shield member 40. The second magnetic shield member 50 is formed of a metal material and has electrical conductivity. Specifically, the second magnetic shield member 50 in the present embodiment is formed of aluminum. In this case, leakage of magnetism from the planar coil 11 through the second magnetic shield member 50 is suppressed. The second magnetic shield member 50 may be formed of an aluminum alloy, copper, stainless steel, or the like. When the coil component 10 is attached to an automobile, the second magnetic shield member 50 may be a metal plate constituting the body of the automobile.

[0075] (Connection terminal) As shown in Fig. 2, the first connection terminal 61 is connected to a radially outer end of the turn portion 1112 of the planar coil 11. The second connection terminal 62 is connected to a radially inner end of the turn portion 1101 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. The connection between the first connection terminal 61 and the turn portion 1112 and the connection between the second connection terminal 62 and the turn portion 1101 may be performed by ultrasonic bonding. However, the connection method is not limited, and for example, a connection using a conductive adhesive may be adopted.

[0076] (grooves and walls) As described above, the groove 24 of the first holding member 20 receives the wall portion 32 of the second holding member 30. The wall portion 32 extends between adjacent turn portions of the planar coil 11. Correspondingly, the groove 24 is formed between adjacent turn portions of the planar coil 11 as viewed in the coil axial direction. In the illustrated example, the wall portion 32 is also formed on the outer side of the outermost turn portion 1112 in the coil radial direction. Correspondingly, the groove 24 is also formed on the outer side of the outermost turn portion 1112 in the coil radial direction. In the illustrated example, the wall portion 32 is also formed on the inner side of the innermost turn portion 1101 in the coil radial direction. Correspondingly, the groove 24 is also formed on the inner side of the innermost turn portion 1101 in the coil radial direction.

[0077] Moreover, in the illustrated example, the wall portion 32 is formed along the spiral shape of the planar coil 11. Therefore, the groove 24 is also formed along the spiral shape of the planar coil 11. Moreover, in the illustrated example, the wall portion 32 is formed in a spiral shape corresponding to the spiral shape of the planar coil 11. Therefore, the groove 24 is also formed in a spiral shape corresponding to the spiral shape of the planar coil 11.

[0078] The groove 24 opens at the first contact surface 20S1. In other words, the groove 24 has an opening 24b formed in the first contact surface 20S1. The wall portion 32 extends into the groove 24 through the opening 24b. The groove 24 has a bottom 24a. The surface defining the groove 24 includes a side surface 24c (hereinafter also referred to as "groove side surface 24c") between the opening 24b and the bottom 24a. The groove side surface 24c includes a pair of groove side surfaces 24ca, 24cb facing each other in the coil radial direction. The pair of groove side surfaces 24ca, 24cb includes an inner groove side surface 24ca located on the inner side in the coil radial direction and an outer groove side surface 24cb located on the outer side in the coil radial direction.

[0079] The wall portion 32 has an apex 32a and a base end 32b. The wall portion 32 is connected to the base portion 31 at the base end 32b. The wall portion 32 has a side surface 32c (hereinafter also referred to as "wall side surface 32c") between the apex portion 32a and the base end 32b. The apex portion 32a faces the bottom portion 24a of the groove 24. In the illustrated example, the apex portion 32a is in contact with the bottom portion 24a. The wall side surface 32c includes an inner wall side surface 32ca facing inward in the coil radial direction and an outer wall side surface 32cb facing outward in the coil radial direction. The inner wall side surface 32ca and the outer wall side surface 32cb of the wall portion 32 face the inner groove side surface 24ca and the outer groove side surface 24cb of the groove 24, respectively. In the illustrated example, the inner wall side surface 32ca and the outer wall side surface 32cb of the wall portion 32 contact the inner groove side surface 24ca and the outer groove side surface 24cb of the groove 24, respectively.

[0080] Here, when the width (dimension along the coil radial direction) of the wall portion 32 is uniform in its protruding direction (coil axial direction) like the wall of the magnetic material disclosed in Patent Document 1, the width (dimension along the coil radial direction) of the groove 24 of the first holding member 20 also needs to be uniform in its depth direction (coil axial direction) as shown in FIG. 16. Such a first holding member 20 is formed by pushing the material 220 for making the first holding member into dies 301, 302 as shown in FIG. 17. The die 302 has a main body portion 303 and a protruding portion 304 extending from the main body portion 303. The protruding portion 304 is formed in a spiral shape corresponding to the groove 24. The width (dimension in the radial direction of the protruding portion 304) of the protruding portion 304 is uniform in the protruding direction of the protruding portion 304. Here, the radial direction of the protrusion 304 means the radial direction of a circle drawn on a plane perpendicular to the central axis C302 and centered at an arbitrary point on the central axis C302 of the protrusion 304. The central axis C302 of the protrusion 304 is a line passing through the center of the spiral shape.

[0081] As described above, the higher the height of the wall portion 32, the higher the effect of suppressing eddy current loss and the higher the coupling coefficient tend to be. The higher the height of the wall portion 32, the deeper the groove 24 of the first holding member 20 must be. The deeper the groove 24, the more difficult it is to form a groove 24 having a uniform width in the depth direction in the first holding member 20. Specifically, the deeper the convex portion 304 of the mold 302 is pressed into the material 220, the more difficult it becomes for the material 220 at the portion into which the convex portion 304 is pressed to flow. Furthermore, if the material 220 contains glass fibers, when the mold 302 is pressed into the material 220, the glass fibers in the material 220 come into contact with the top surface of the convex portion 304, preventing the mold 302 from entering the material 220. If the mold 302 is forcibly pressed into the material 220, the mold 302 may be damaged. 17, it is difficult to form deep grooves 24 in first holding member 20. The depth of grooves 24 that can be formed in first holding member 20 by die 302 is at most 2 mm.

[0082] Furthermore, the higher the wall portion 32 is, the less material 220 remains between the bottom 24a of the groove 24 of the first holding member 20 and the outer surface 20S3, which may reduce the strength of the first holding member 20. If the strength of the first holding member 20 is reduced, the strength of the coil device 10 will also be reduced.

[0083] Considering the above points, in this embodiment, the width (dimension along the coil radial direction) of the bottom 24a of the groove 24 of the first holding member 20 is narrower than the width (dimension along the coil radial direction) at the height position of the first contact surface 20S1 of the groove 24. Correspondingly, the width (dimension along the coil radial direction) of the top 32a of the wall portion 32 of the second holding member 30 is narrower than the width (dimension along the coil radial direction) at the height position of the first contact surface 20S1 of the wall portion 32.

[0084] The first holding member 20 having such a groove 24 can be formed using a mold 202 as shown in FIG. 5. That is, the mold 200 has a main body 203 and a protruding portion 204 extending from the main body 203. The protruding portion 204 has a spiral shape corresponding to the spiral shape of the groove 24. Therefore, the protruding portion 204 corresponds to the shape of the gap extending between adjacent turn portions of the planar coil 11. The protruding portion 204 has an apex 204a and a base end 204b. The protruding portion 204 is connected to the main body 203 at the base end 204b.

[0085] 5 indicates a central axis (hereinafter also referred to as "mold central axis C202") passing through the center of the spiral shape of the protruding portion 204. Hereinafter, the axial direction of the protruding portion 204 (hereinafter also referred to as "mold axial direction") means a direction extending on the mold central axis C202 or a direction parallel to the mold central axis C202. In addition, the radial direction of the protruding portion 204 (hereinafter also referred to as "mold radial direction") means a radial direction of a circle drawn on a plane centered on an arbitrary point on the mold central axis C202 and perpendicular to the mold central axis C202.

[0086] In this embodiment, the width of the top 204a (dimension along the die radial direction) is narrower than the width of the base end 204b (dimension along the die radial direction). By having the convex portion 204 of the die 202 have such a shape, when the convex portion 204 is pressed into the material 220, the material 220 in the portion into which the convex portion 204 is pressed can be guided in the width direction of the convex portion 204. In other words, the shape of the convex portion 204 can promote the flow of the material 220 in the portion into which the convex portion 204 is pressed. Therefore, it becomes easy to press the convex portion 204 deeply into the material 220. In addition, when the material 220 contains glass fiber, the width of the top 204a of the convex portion 204 is narrower than the width of the base end 204b, so that the area of ​​the portion of the convex portion 204 that contacts the glass fiber (top portion 204a) is smaller than that shown in FIG. 17. As a result, the risk of damage to the protrusions 204 is reduced even if the protrusions 204 are pressed deeply into the material 220. As described above, according to the die 202 of the present embodiment, deep grooves 24 can be easily formed in the first holding member 20. This makes it easier to mold the first holding member 20. Furthermore, by deepening the grooves 24 in the first holding member 20, the height 32H of the wall portions 32 can be increased, and the performance of the coil device 10 is improved.

[0087] From the viewpoint of effectively concentrating the pressing force applied to the mold 200 on the apex 204a, the width of the apex 204a is preferably not more than half, and more preferably not more than one third, of the base end 204b.

[0088] Furthermore, even if a deep groove 24 is formed in the first holding member 20, since the width of the bottom 24a is narrow, a larger amount of material 220 can remain between the groove 24 and the outer surface 20S3 of the first holding member 20. This prevents a decrease in the strength of the first holding member 20, and also prevents a decrease in the strength of the coil component 10.

[0089] 5, the protruding portion 204 also forms a space surrounded by the covering portion 28 in the first holding member 20. In order to make the width of this space (the dimension along the coil radial direction) uniform in the coil axial direction, the width of a portion 204d (hereinafter also referred to as "base end portion 204d") continuing from the base end 204b of the protruding portion 204 is uniform in the mold axial direction.

[0090] Since the space surrounded by the covering portion 28 is uniform in the coil axial direction, the width of a portion 32d (hereinafter, also referred to as "base end portion 32d") continuing to the base end 32b of the wall portion 32 is also uniform in the coil axial direction. In the illustrated example, the base end portion 32d continues to the height position of the first surface 11A of the planar coil 11.

[0091] In the illustrated example, at least one of the pair of groove side surfaces 24ca, 24cb that define the groove 24 has an inclined surface 24s that is inclined with respect to the coil axial direction (hence, with respect to the coil central axis C10). Correspondingly, at least one of the pair of wall side surfaces 32ca, 32cb of the wall portion 32 has an inclined surface 32s that is inclined with respect to the coil axial direction (hence, with respect to the coil central axis C10). The first holding member 20 having such a groove 24 can be molded by the following mold 202. That is, as shown in FIG. 5, the convex portion 204 of the mold 202 has a side surface 204c (hereinafter also referred to as "mold side surface 204c") between the top portion 204a and the base end 204b. The mold side surface 204c includes a pair of mold side surfaces 204ca, 204cb that face each other in the mold radial direction. The pair of mold side surfaces 204ca, 204cb includes an inner mold side surface 204ca located on the inner side in the mold radial direction and an outer mold side surface 204cb located on the outer side in the mold radial direction. At least one of the pair of mold side surfaces 204ca, 204cb has an inclined surface 204s inclined with respect to the mold axial direction (hence, with respect to the mold central axis C202).

[0092] In the example shown in FIG. 3, the outer groove side surface 24cb of the groove 24 has an inclined surface 24s. Correspondingly, the outer wall side surface 32cb of the wall portion 32 has an inclined surface 32s. Also, the outer mold side surface 204cb of the mold 200 has an inclined surface 204s (see FIG. 5). More specifically, as shown in FIG. 3, the inclined surface 24s of the outer groove side surface 24cb is inclined with respect to the coil axial direction so as to approach the coil central axis C10 from the opening 24b toward the bottom 24a. Similarly, the inclined surface 32s of the outer wall side surface 32cb is inclined with respect to the coil axial direction so as to approach the coil central axis C10 from the base end 32b toward the top 32a. Also, as shown in FIG. 5, the inclined surface 204s of the outer mold side surface 204cb is inclined with respect to the mold axial direction so as to approach the mold central axis C202 from the base end 204b toward the top 204a.

[0093] 3, the inner groove side surface 24ca is parallel to the coil axis direction from the opening 24b to the bottom 24a. Also, the inclined surface 24s of the outer groove side surface 24cb is continuous from the opening 24b to the bottom 24a.

[0094] In the example shown in FIG. 3, the inner side wall 32ca of the wall 32 is parallel to the coil axis direction from the base end 32b to the apex 32a. In the outer side wall 32cb of the wall 32, the region between the base end 32b and the inclined surface 32s is parallel to the coil axis direction. This region corresponds to the base end 32d described above. In the example shown in FIG. 3, the inclined surface 32s is continuous from the height position of the first surface 11A of the outer side wall 32cb to the apex 32a. Therefore, the outer side wall 32cb is parallel to the coil axis direction from the base end 32b to the height position of the first surface 11A. That is, in the example shown in FIG. 3, the dimension along the coil axis direction of the base end 32d of the wall 32 (the portion connected to the base end 32b and having a uniform width in the coil axis direction) is the same as the thickness of the planar coil 11. Therefore, the base end 32d does not protrude from the first surface 11A of the planar coil 11.

[0095] In this example, as shown in FIG. 5, the inner mold side surface 204ca of the protrusion 204 is parallel to the mold axis direction from the base end 204b to the apex 204a. In addition, the region 204cd between the base end 204b and the inclined surface 204s of the outer mold side surface 204cb of the protrusion 204 is parallel to the mold axis direction. This region corresponds to the base end portion 204d described above. The dimension of this region 204cd along the mold axis direction is the same as the thickness of the planar coil 11. The inclined surface 204s is continuous from the edge of the region 204cd opposite the base end 204b to the apex 32a.

[0096] <Method of manufacturing coil component 10> Next, an example of a method for manufacturing the coil device 10 will be described.

[0097] First, molds 201 and 202 shown in Fig. 5 are prepared, and the planar coil 11 is placed on the main body 203 of the mold 202 as shown in Fig. 6. At this time, the planar coil 11 is placed on the main body 203 so that the protruding parts 204 of the mold 202 extend out from between adjacent turn parts of the planar coil 11.

[0098] Also, a material 220 for producing the first holding member is prepared. In the illustrated example, the material 220 is a molding material formed into a plate shape as a whole. Next, the molding material 220 is heated, and as shown in FIG. 6, the molding material 220 is placed on the mold 202 and the planar coil 11. Next, as shown in FIG. 7, the planar coil 11 and the molding material 220 are heat-pressed between the mold 202 and another mold 201.

[0099] The molding material 220 softens and melts between the molds 201 and 202. As a result, a groove 24 corresponding to the protrusion 204 of the mold 202 is formed on one surface of the molding material 220. In this manner, the first holding member 20 having the groove 24 is formed. When viewed in the coil axial direction, the groove 24 is formed between adjacent turn portions of the planar coil 11. In addition, the first holding member 20 is cooled and solidified, so that the first holding member 20 and the planar coil 11 are integrated together. In this manner, the coil intermediate material 10M shown in FIG. 4 is produced.

[0100] After removing the mold 200 from the coil intermediate material 10M, the second holding member 30 is formed on the coil intermediate material 10M (more specifically, on the second surface 11B of the planar coil 11) as shown in FIG. 8. At this time, the groove 24 is filled with the second holding member 30. The second holding member 30 is integrated with the coil intermediate material 10M. Thereafter, the first magnetic shield member 40 and the second magnetic shield member 50 are disposed on the second holding member 30. In this manner, the coil component 10 is manufactured.

[0101] <Applications of coil components> The coil component 10 according to this embodiment can be used as a power transmitting coil in the power transmitting device 1 of the wireless power transmission system S described above, and can be used as a power receiving coil in the power receiving device 2.

[0102] When the coil component 10 is used as a 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 an AC power supply as shown in Fig. 1. When a high frequency current is supplied to the coil component 10, the current can be passed 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 be passed 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. This makes it possible to generate a magnetic field including magnetic field lines along the coil central axis C10.

[0103] On the other hand, when the coil component 10 is used as a receiving coil, a high-frequency current can be generated in the planar coil 11 by receiving or generating a magnetic field including magnetic lines of force that pass through the inside of the planar coil 11. Then, this high-frequency current can be supplied to an external device from the first connection terminal 61 or the second connection terminal 62.

[0104] The coil component 10 can also be used in a transformer, an antenna, etc. For example, when the coil component 10 functions as a primary coil in a transformer, the first connection terminal 61 and the second connection terminal 62 are connected to an AC power source. When a high-frequency current is supplied, a magnetic flux can be supplied from the center of the planar coil 11 to the iron core.

[0105] <Modification> It should be noted that various modifications can be made to the above-described embodiment. For example, the coil component 10 may include a plurality of planar coils. More specifically, the coil component 10 may include another planar coil between the planar coil 11 and the first magnetic shield member 40. The number of planar coils included in the coil component 10 is not particularly limited. When the coil component 10 includes the other planar coil, the planar coil 11 and the other planar coil may be stacked along the coil axis direction of the planar coil 11. In this case, the other planar coil may be embedded in the base 31 of the second holding member 30. In this case, one of the connection terminals 61 and 62 may be connected to the planar coil 11, and the other of the connection terminals 61 and 62 may be connected to the other planar coil. In this case, the planar coil 11 and the other planar coil may be electrically connected to each other.

[0106] In addition, the shapes of the groove 24, the wall portion 32, and the protrusion 204 are not limited to the above-mentioned shapes. For example, as shown in Fig. 9, the inner groove side surface 24ca of the groove 24 may have an inclined surface 24s inclined with respect to the coil axis direction. Correspondingly, the inner wall side surface 32ca of the wall portion 32 may have an inclined surface 32s inclined with respect to the coil axis direction. In addition, although not shown, the inner mold side surface 204ca of the mold 202 may have an inclined surface 204s inclined with respect to the mold axial direction.

[0107] In this case, the inclined surface 24s of the inner groove side surface 24ca is inclined with respect to the coil axial direction so as to move away from the coil central axis C10 from the opening 24b toward the bottom 24a. Similarly, the inclined surface 32s of the inner wall side surface 32cb is inclined with respect to the coil axial direction so as to move away from the coil central axis C10 from the base end 32b toward the apex 32a. Moreover, the inclined surface 204s of the inner mold side surface 204ca is inclined with respect to the mold axial direction so as to move away from the mold central axis C202 from the base end 204b toward the apex 204a.

[0108] Furthermore, according to the findings of the inventors, the performance of the coil device 10 is improved when the inner wall side surface 32ca has an inclined surface 32s and the outer wall side surface 32cb does not have an inclined surface 32s, as shown in FIG. 9, compared to when the outer wall side surface 32cb has an inclined surface 32s and the inner wall side surface 32ca does not have an inclined surface 32s, as shown in FIG. 3.

[0109] Of course, as shown in Fig. 10, both the inner wall side surface 32ca and the outer wall side surface 32cb of the wall portion 32 may have the inclined surface 32s. In this case, both the inner groove side surface 24ca and the outer groove side surface 24cb of the groove 24 may have the inclined surface 24s. Also, although not shown, both the inner mold side surface 204ca and the outer mold side surface 204cb of the mold 202 may have the inclined surface 204s.

[0110] In the above-mentioned example, the groove 24 and the inclined surfaces 24s, 32s of the wall portion 32 extend from the height position of the first surface 11A of the planar coil 11 to the bottom portion 24a or the top portion 32a, but are not limited thereto. In the example shown in Fig. 11 to Fig. 13, the groove 24 and the inclined surfaces 24s, 32s of the wall portion 32 extend from a height position different from the height position of the first surface 11A of the planar coil 11 to the bottom portion 24a or the top portion 32a.

[0111] More specifically, in the example shown in FIG. 11 to FIG. 13, the dimension of the base end 32d of the wall portion 32 along the coil axis direction is larger than the thickness of the planar coil 11. That is, the base end 32d extends from the first surface 11A of the planar coil 11 toward the outer surface 20S3 of the first holding member 20. According to the knowledge obtained by the inventor, the performance of the coil component 10 is improved as the amount 32dH of the base end 32d extending from the first surface 11A of the planar coil 11 toward the outer surface 20S3 (hereinafter, also referred to as "the protruding height 32dH of the base end 32d from the planar coil 11") increases. In the example shown in FIG. 2 to FIG. 8, the protruding height 32dH of the base end 32d from the planar coil 11 is 0 mm. In contrast, in the example shown in FIG. 11 to FIG. 13, the protruding height 32dH of the base end 32d from the planar coil 11 is larger than 0 mm. The protruding height 32dH in the examples shown in FIGS. 11 to 13 is not particularly limited, but from the viewpoint of effectively improving the performance of the coil device 10, it is preferably 1 mm or more.

[0112] <Coil component performance evaluation simulation> The following describes the simulations carried out to evaluate the performance of the coil components according to Examples 1 to 9 and Comparative Examples 1 to 5. The simulations were carried out using Femtet (registered trademark) manufactured by Murata Software Corporation.

[0113] The common conditions for the simulations of Examples 1 to 9 and Comparative Examples 1 to 5 are as follows. The coil component 10 includes a spirally formed planar coil 11, a first holding member 20, a second 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, similar to the example shown in Figures 2 to 5. The coil component 10 has a single planar coil 11. The planar coil 11 is wound in a generally regular octagonal shape. The planar coil 11 has first to twelfth turn portions 1101 to 1112. The distance between adjacent turn portions 1101, 1102, 1111, 1112 is 3 mm. However, the distance between the inner end portion in the coil radial direction of the first turn portion 1101 and the inner end portion in the coil radial direction of the second turn portion 1102 is 6 mm. The planar coil 11 is made of copper. The line width of the planar coil 11 is 7.5 mm, and the thickness is 1.0 mm. The diameter of the planar coil 11 is 295 mm. The first holding member 20 is made of glass fiber reinforced polyamide. The width of the opening 24b of the groove 24 is 2.5 mm. The second holding member 30 is made of a resin containing a magnetic material. The second holding member 30 has a relative magnetic permeability of 10. The first magnetic shield member 40 is made of a ferrite plate. The first magnetic shield member 40 has a relative magnetic permeability of 3,000. The second magnetic shield member 50 is made of aluminum. The first connection terminal 61 and the second connection terminal 62 are connected to the inner end and the outer end of the planar coil 11 in the coil radial direction. The high frequency current supplied to the planar coil 11 is 40 A and has a frequency of 85 KHz.

[0114] The common conditions for the simulations in Examples 1 to 9 are as follows. At least one of the pair of wall side surfaces 32ca, 32cb of the wall portion 32 has an inclined surface 32s.

[0115] The individual conditions in the simulations of Examples 1 to 9 are as follows. <Example 1> The wall portion 32 and the groove 24 have the shapes shown in FIG. The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 2 mm. The protruding height 32dH of the base end 32d from the planar coil 11 is 0 mm. <Example 2> The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 4 mm. The other conditions are the same as in Example 1. <Example 3> The wall portion 32 and the groove 24 have the shapes shown in FIG. The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 2 mm. The protruding height 32dH of the base end 32d from the planar coil 11 is 0 mm. <Example 4> The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 4 mm. The other conditions are the same as in Example 3. <Example 5> The wall portion 32 and the groove 24 have the shapes shown in FIG. The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 2 mm. The protruding height 32dH of the base end 32d from the planar coil 11 is 0 mm. <Example 6> The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 4 mm. The other conditions were the same as in Example 5. <Example 7> The wall portion 32 and the groove 24 have the shapes shown in FIG. The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 4 mm. The protruding height 32dH of the base end 32d from the planar coil 11 is 2 mm. <Example 8> The wall portion 32 and the groove 24 have the shapes shown in FIG. The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 4 mm. The protruding height 32dH of the base end 32d from the planar coil 11 is 2 mm. <Example 9> The wall portion 32 and the groove 24 have the shapes shown in FIG. The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 4 mm. The protruding height 32dH of the base end 32d from the planar coil 11 is 2 mm.

[0116] The common conditions in the simulations of Comparative Examples 1 to 5 are as follows: Neither of the pair of wall side surfaces 32ca, 32cb of the wall portion 32 has the inclined surface 32s. In other words, the wall portion 32 is constituted only by the base end portion 32d of the wall portion 32 of the first to ninth embodiments.

[0117] The individual conditions in the simulations of Comparative Examples 1 to 5 are as follows. <Comparative Example 1> The wall portion 32 and the groove 24 have the shapes shown in FIG. The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 0 mm. <Comparative Example 2> The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 1 mm. The other conditions are the same as those in Comparative Example 1. <Comparative Example 3> The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 2 mm. The other conditions are the same as those in Comparative Example 1. <Comparative Example 4> The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 3 mm. The other conditions are the same as those in Comparative Example 1. <Comparative Example 5> The protruding height 32Ha of the wall portion 32 from the planar coil 11 is 4 mm. The other conditions are the same as those in Comparative Example 1.

[0118] <Evaluation> The results of the simulation are shown in Fig. 14 and Fig. 15. In Fig. 14 and Fig. 15, "Q value", "L" and "Z" mean the Q value, inductance and impedance of the coil device 10.

[0119] 14 and 15, the Q values ​​of the coil components 10 in Examples 1, 3, and 5 are equivalent to the Q value of the coil component in Comparative Example 2. Here, in Examples 1, 3, and 5, the protruding height 32dH of the base end 32d from the planar coil 11 is 0 mm. In contrast, in Comparative Example 1, the protruding height 32H of the wall portion 32 from the planar coil 11 is 1 mm.

[0120] 14 and 15, the Q values ​​of the coil components 10 in Examples 2, 4, and 6 are equivalent to the Q value of the coil component in Comparative Example 3. Here, in Examples 2, 4, and 6, the protruding height 32dH of the base end 32d from the planar coil 11 is 0 mm. In contrast, in Comparative Example 2, the protruding height 32H of the wall portion 32 from the planar coil 11 is 2 mm.

[0121] 14 and 15, the Q value of the coil components 10 of Examples 7 to 9 is equivalent to the Q value of the coil components of Comparative Example 4 or Comparative Example 5. In Examples 7 to 9, the protruding height 32dH of the base end 32d from the planar coil 11 is 2 mm. In contrast, in Comparative Example 4 and Comparative Example 5, the protruding height 32H of the wall 32 from the planar coil 11 is 3 mm and 4 mm, respectively. Note that the width of the wall 32 of Comparative Example 4 and Comparative Example 5 is uniform in the protruding direction, and the protruding height 32H from the planar coil 11 is greater than 2 mm. For this reason, as described above, it is actually difficult to form the groove 24 that accommodates the wall 32 of Comparative Example 4 and Comparative Example 5 in the first holding member 20.

[0122] Furthermore, as can be understood by comparing Examples 2 and 7, Examples 4 and 8, and Examples 6 and 9, the Q value of the coil device 10 improves as the protruding height 32dH of the base end 32d from the planar coil 11 increases.

[0123] Furthermore, as can be understood by comparing Examples 1 and 3, Examples 2 and 4, and Examples 7 and 8, when only one of the pair of wall side surfaces 32ca, 32cb of the wall portion 32 has an inclined surface 32s, the Q value of the coil device 10 including the inclined surface 32s on the inner wall side surface 32ca of the wall portion 32 tends to be improved compared to the coil device 10 including the inclined surface 32s on the outer wall side surface 32cb of the wall portion 32.

[0124] The coil component 10 according to the embodiment described above includes a planar coil 11, a first holding member 20, and a second holding member 30. The planar coil 11 has a spiral shape and includes a first surface 11A and a second surface 11B opposite to the first surface 11A. The first holding member 20 overlaps the planar coil 11 so as to face the first surface 11A, and holds the planar coil 11. The second holding member 30 sandwiches the planar coil 11 between the first holding member 20. The planar coil 11 includes a plurality of turn portions 11n arranged in a coil radial direction, which is a radial direction of the planar coil 11. The first holding member 20 has a contact surface 20S1 that contacts the first surface 11A. A groove 24 is formed in the contact surface 20S1. The groove 24 extends between adjacent turn portions of the planar coil 11 when viewed in a coil axis direction, which is an axial direction of the planar coil 11. The second holding member 30 has a base 31 and a wall 32. The base 31 contacts the second surface 11B of the planar coil 11. The wall 32 extends from the base 31 through between the adjacent turn portions of the planar coil 11 into the groove 24 of the first holding member 20. The width of the bottom 24a of the groove 24 is narrower than the width of the groove 24 at the height position (position in the coil axis direction) of the contact surface 20S1. According to such a coil component 10, it is easy to deepen the depth of the groove 24, so that it is easy to increase the height of the wall 32 and improve the performance of the coil component 10. Moreover, according to such a coil component 10, it is possible to leave more material 220 between the groove 24 of the first holding member 20 and the outer surface 20S3 of the first holding member 20. Therefore, the reduction in strength of the first holding member 20 due to the formation of the groove 24 is suppressed, and the reduction in strength of the coil component 10 is also suppressed.

[0125] The manufacturing method of the coil component 10 according to the embodiment described above includes the steps of preparing a mold 202, arranging the planar coil 11 in the mold 202, fabricating the coil intermediate material 10M, removing the mold 202 from the coil intermediate material 10M, and forming the second holding member 30. The mold 202 has a main body 203 and a spiral-shaped protruding portion 204 extending from the main body 203. The planar coil 11 has a spiral shape corresponding to the spiral shape of the protruding portion 204. The planar coil 11 is arranged on the main body 204 such that the protruding portion 204 extends from between adjacent turn portions of the planar coil 11. In the step of fabricating the coil intermediate material 10M, the first holding member 20 is formed by pressing a material 220 for fabricating the first holding member against the mold 202 in which the planar coil 11 is arranged, and the first holding member 20 and the planar coil 11 are integrated together. The width of the top 204a of the protruding portion 204 of the mold 202 is narrower than the width of the protruding portion 204 at the connection position with the main body portion 203 (i.e., the width of the base end 204b). According to such a manufacturing method for the coil component 10, it is easy to form a deep groove 24 in the first holding member 20, and as a result, it is possible to easily manufacture a coil component 10 including a high-height wall portion 32. Therefore, it is possible to easily manufacture a coil component 10 with high performance. Furthermore, in the coil component 10 manufactured by such a manufacturing method, it is possible to leave more material 220 between the groove 24 of the first holding member 20 and the outer surface 20S3 of the first holding member 20. Therefore, the decrease in strength of the first holding member 20 caused by the formation of the groove 24 is suppressed, and the decrease in strength of the coil component 10 is also suppressed.

[0126] Although several modifications to the above-mentioned embodiment have been described, it is of course possible to apply a plurality of modifications in appropriate combination. [Explanation of symbols]

[0127] S…Power transmission system 1...Power transmission device 1A…High frequency current supply 2...Power receiving device 2A…Conversion section 10...Coil parts 10M...Coil intermediate material 11...Planar coil 11A…First side 11B...Second side 11n…Turn section 11E…Conductor 20...First holding member 24...Groove 24s...Slope 30...Second holding member 31...Base 32...Wall part 32s…Slope surface 40...First magnetic shield member 50...Second magnetic shield member 61…First connection terminal 62…Second connection terminal 202...Mold 203…Main body 204…Convex part 204s…Slope surface 220…molding material C10: Coil central axis C202: Die center axis

Claims

1. a planar coil having a spiral shape and including a first surface and a second surface opposite the first surface; a first holding member overlapping the planar coil so as to face the first surface and holding the planar coil; a second holding member that sandwiches the planar coil between the first holding member and the second holding member, the planar coil includes a plurality of turn portions arranged in a coil radial direction, which is a radial direction of the planar coil, the first holding member has a contact surface that contacts the first surface, a groove is formed on the contact surface, the groove extending between adjacent turn portions of the planar coil as viewed in a coil axis direction that is an axial direction of the planar coil; the second holding member has a base portion in contact with the second surface of the planar coil, and a wall portion extending from the base portion through spaces between adjacent turn portions of the planar coil and into the groove of the first holding member, A coil component, wherein a width of the bottom of the groove is narrower than a width of the groove at a height position of the contact surface.

2. a surface of the first holding member that defines the groove has a pair of groove side surfaces that face each other in the coil radial direction, The coil component according to claim 1 , wherein at least one of the pair of groove side surfaces has an inclined surface that is inclined with respect to the coil axial direction.

3. The coil component according to claim 2 , wherein one of the pair of groove side surfaces located on an outer side in the coil radial direction has the inclined surface.

4. The coil component according to claim 2 , wherein one of the pair of groove side surfaces located on an inner side in the coil radial direction has the inclined surface.

5. The coil component according to claim 2 , wherein each of the pair of groove side surfaces has an inclined surface that is inclined with respect to the coil axial direction.

6. the wall portion has a base end portion extending from the base portion along the coil axis direction with a uniform width, The coil component according to claim 1 , wherein a dimension of the base end along the coil axial direction is greater than a thickness of the planar coil.

7. The coil component according to claim 1 , wherein the distance between the top of the groove and the contact surface is 2 mm or more.

8. The coil component according to claim 1 , wherein the width of the bottom of the groove is equal to or smaller than half the width of the groove at a height position of the contact surface.

9. The coil component according to claim 1 , wherein the first retaining member includes a fiber.

10. The coil component according to claim 1 , wherein the first holding member is non-magnetic and insulating.

11. The coil component according to claim 1 , wherein the second holding member is magnetic.

12. The coil component according to claim 1 , wherein the planar coil is formed in a plate shape.

13. A power transmitting device comprising the coil component according to claim 1.

14. A power receiving device comprising the coil component according to claim 1.

15. The power transmission device and the power receiving device are provided. A power transfer system, wherein at least one of the power transmitting device and the power receiving device comprises the coil component according to claim 1 .

16. A moving body comprising the coil component according to claim 1.

17. A method for manufacturing a coil component according to claim 1, A step of preparing a mold having a main body and a spiral-shaped protrusion extending from the main body; a step of disposing a spiral-shaped planar coil corresponding to the spiral shape of the protrusion on the main body of the mold such that the protrusion extends between adjacent turn portions of the planar coil; a step of pressing a material for manufacturing a first holding member against a die in which the planar coil is disposed, thereby forming a first holding member, and manufacturing a coil intermediate material in which the first holding member and the planar coil are integrated; removing the die from the coil intermediate material; a step of forming a second holder covering the planar coil on the coil intermediate material after removing the die from the coil intermediate material; Equipped with The manufacturing method, wherein the width of the top of the convex portion of the mold is narrower than the width of the convex portion at a connection position with the main body portion.

18. The protrusion has a pair of die side surfaces facing each other in a die radial direction, which is a radial direction of the protrusion, The manufacturing method according to claim 17 , wherein at least one of the pair of mold side surfaces has an inclined surface that is inclined with respect to a mold axial direction that is an axial direction of the protrusion.

19. The manufacturing method according to claim 18 , wherein one of the pair of mold side surfaces located on the outer side in the mold radial direction has an inclined surface inclined with respect to the mold axial direction.

20. The manufacturing method according to claim 18 , wherein one of the pair of mold side surfaces located radially inward in the mold has an inclined surface inclined with respect to the mold axial direction.

21. The manufacturing method according to claim 18 , wherein each of the pair of mold side surfaces has an inclined surface inclined with respect to the mold axial direction.

22. The method according to claim 17 , wherein the width of the top of the protrusion is equal to or smaller than half the width of the protrusion at the connection position with the main body.

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