Coil unit, power transmission device, power reception device, power transmission system, and mobile

Abstract

To provide a coil unit, a power transmission device, a power reception device, a power transmission system, and a mobile for reducing the size and improving performance to implement efficient power transfer.SOLUTION: A coil unit (5) comprises: a coil (10) including a coil element (10i) formed in a spiral shape around any center axis C; a magnetic material resin layer (20); a first shield member (30); and a second shield member (40). The coil has a first principal surface (10a) and a second principal surface (10b) which is a surface on the opposite side of the first principal surface. The magnetic material resin layer is in direct contact with the second principal surface of the coil. The coil and magnetic material resin layer, the first shield member, and the second shield member are laminated in this order in a direction from the first principal surface to the second principal surface. The first shield member is divided in a plurality of shield small pieces (30P).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a coil unit, a power transmitting device, a power receiving device, a power transfer system, and a moving object. [Background technology]

[0002] Wireless power transmission systems that transmit power contactlessly are becoming more common. JP2021-27112A discloses a coil unit used in a power transmitter and a power receiver of a wireless power transmission system. The coil unit includes a spirally wound coil. When power is supplied to the coil of the power transmitter, a magnetic field is generated in the coil. This magnetic field causes a current to flow in the coil of the power receiver.

[0003] When transmitting large amounts of power without contact, a large high-frequency current flows through a resonant circuit that includes a coil. This increases the amount of heat generated by the coil. The amount of heat generated by the coil increases due to, for example, the skin effect.

[0004] When litz wire is used as a coil, the skin effect is suppressed, which reduces the heat generated by the coil. However, since litz wire is formed by twisting together many enameled wires, the manufacturing cost is high and it takes time and effort. In high-power systems, the coil can become large, which can further increase the manufacturing cost and effort.

[0005] On the other hand, as disclosed in JP2021-27112A, a technique is also known that employs a spiral, plate-shaped planar coil with a rectangular conductor cross section. Such a planar coil can reduce the thickness of the coil.

[0006] In a wireless power transmission system for an electric vehicle, a power transmitter is installed on the road surface, such as in a parking lot, and a power receiver is installed in the electric vehicle. Such a power transmitter and / or power receiver includes a coil unit for generating a magnetic field or generating a current under the influence of the magnetic field. In the field of vehicles, the installation space for the coil unit is severely restricted, so it is desirable to reduce the size of the coil unit. Therefore, the use of the above-mentioned planar coil as the coil unit has been considered. However, simply reducing the thickness of the coil does not sufficiently reduce the size of the coil unit.

[0007] The first invention has been made in consideration of these points, and has as its object to reduce the dimensions of the coil unit.

[0008] Furthermore, in wireless power transmission systems, it is desirable to improve the performance of the coil unit to perform efficient power transmission.

[0009] The second invention has been made in consideration of these points, and has an object to realize efficient power transmission. DISCLOSURE OF THE INVENTION

[0010] <First invention> A first aspect of the present invention aims to reduce the dimensions of a coil unit.

[0011] The coil unit according to the first invention comprises: a coil including coil elements formed in a spiral shape around a central axis, a magnetic resin layer, a first shielding member, and a second shielding member; the coil has a first main surface and a second main surface opposite to the first main surface, the magnetic resin layer is in direct contact with the second main surface of the coil, the coil and the magnetic resin layer, the first shielding member, and the second shielding member are laminated in this order in a direction from the first main surface toward the second main surface, The first shield member is divided into a plurality of shielding pieces.

[0012] In the coil unit according to the first aspect of the present invention, The coil element may include a conductor having a spiral shape; The magnetic resin layer may be in direct contact with the conductor.

[0013] In the coil unit according to the first aspect of the present invention, The first shield member may include ferrite.

[0014] In the coil unit according to the first aspect of the present invention, The distance between the first shielding member and the second shielding member may be 2 mm or less.

[0015] In the coil unit according to the first aspect of the present invention, A heat conducting member may be disposed between the first shielding member and the second shielding member.

[0016] In the coil unit according to the first aspect of the present invention, The coil element may include a first straight line portion group consisting of a plurality of first straight line portions arranged in a radial direction and extending in a first direction, and a second straight line portion group consisting of a plurality of second straight line portions arranged in a radial direction and extending in a second direction non-parallel to the first direction, wherein each second straight line portion is connected to an adjacent first straight line portion, The first shield member may have gaps formed therein that extend linearly between adjacent shield pieces and cross at least a portion of the first group of linear portions when viewed in the axial direction.

[0017] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed between the gap and at least a part of the first group of straight line portions may be 80° to 100°.

[0018] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the gaps and at least some of the first group of straight line portions may be perpendicular to each other.

[0019] In the coil unit according to the first aspect of the present invention, The gap may extend from a position radially inward of the first group of straight line portions to a position radially outward of the first group of straight line portions.

[0020] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the gap may extend between the second group of straight portions and the central axis.

[0021] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the gap or an extension thereof may overlap the central axis.

[0022] In the coil unit according to the first aspect of the present invention, The first shield member may have another gap formed therein that extends linearly between adjacent shield pieces and that extends along the first straight line portions within the first straight line portion group when viewed in the axial direction, The other gap may extend closer to the central axis than the smallest integer-th first straight section, counting from the innermost first straight section among the plurality of first straight sections, that is equal to or greater than the total number of the plurality of first straight sections divided by 3.

[0023] In the coil unit according to the first aspect of the present invention, The first shield member may have another gap formed therein that extends linearly between adjacent shield pieces and that extends along the second straight line portions within the second straight line portion group when viewed in the axial direction, The other gap may extend closer to the central axis than the smallest integer-th second straight section, counting from the innermost second straight section among the plurality of second straight sections, that is equal to or greater than the total number of the plurality of second straight sections divided by 3.

[0024] In the coil unit according to the first aspect of the present invention, The first shield member may have another gap formed therein that extends linearly between adjacent shield pieces and that extends along the first straight line portions within the first straight line portion group when viewed in the axial direction, The other gap may extend on the side opposite the central axis from the smallest integer-th first straight section that is equal to or greater than the total number of the plurality of first straight sections divided by 3, counting from the outermost first straight section among the plurality of first straight sections.

[0025] In the coil unit according to the first aspect of the present invention, The first shield member may have another gap formed therein that extends linearly between adjacent shield pieces and that extends along the second straight line portions within the second straight line portion group when viewed in the axial direction, The other gap may extend on the side opposite the central axis from the smallest integer-th second straight section that is equal to or greater than the total number of the plurality of second straight sections divided by 3, counting from the outermost second straight section among the plurality of second straight sections.

[0026] In the coil unit according to the first aspect of the present invention, The coil element comprises: a first straight line portion group consisting of a plurality of first straight line portions arranged in a radial direction and extending in a first direction; a second straight line portion group including a plurality of second straight line portions arranged in a radial direction and extending in a second direction non-parallel to the first direction; an intermediate curved line portion group arranged between the first straight line portion group and the second straight line portion group and including a plurality of intermediate curved line portions; may further comprise Adjacent ends of the first straight line portion and the second straight line portion may be connected via the intermediate curved portion.

[0027] In the coil unit according to the first aspect of the present invention, The first shield member may have gaps formed therein that extend linearly between adjacent shield pieces and that traverse at least a portion of the group of intermediate curved portions when viewed in the axial direction.

[0028] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed between the gap and the tangent line of at least some of the intermediate curved portions may be 80° to 100°.

[0029] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the gap and the tangent may be perpendicular to each other.

[0030] In the coil unit according to the first aspect of the present invention, The coil element comprises: a first straight line portion group consisting of a plurality of first straight line portions arranged in a radial direction and extending in a first direction; a second straight line portion group including a plurality of second straight line portions arranged in a radial direction and extending in a second direction non-parallel to the first direction; a first intermediate straight line portion group arranged between the first straight line portion group and the second straight line portion group and including a plurality of first intermediate straight line portions; may further comprise Adjacent ends of the first linear portion and the second linear portion may be connected via the first intermediate linear portion.

[0031] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed by the first linear portion and the first intermediate linear portion may be 125° to 145°, When viewed in the axial direction, the angle formed between the second straight portion and the first intermediate straight portion may be 125° to 145°.

[0032] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed by the first linear portion and the first intermediate linear portion may be 135°, When viewed in the axial direction, the angle formed by the second straight portion and the first intermediate straight portion may be 135°.

[0033] In the coil unit according to the first aspect of the present invention, The coil elements may have a generally octagonal shape.

[0034] In the coil unit according to the first aspect of the present invention, The coil element may have an overall regular octagonal shape.

[0035] In the coil unit according to the first aspect of the present invention, The first shield member may have gaps formed therein that extend linearly between adjacent shield pieces and that traverse at least a portion of the first intermediate straight portion group when viewed in the axial direction.

[0036] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed between the gap and the at least part of the first group of intermediate straight portions may be 80° to 100°.

[0037] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the gaps and at least some of the first group of intermediate straight portions may be perpendicular to each other.

[0038] In the coil unit according to the first aspect of the present invention, The coil element comprises: a first straight line portion group consisting of a plurality of first straight line portions arranged in a radial direction and extending in a first direction; a second straight line portion group including a plurality of second straight line portions arranged in a radial direction and extending in a second direction non-parallel to the first direction; a first intermediate straight line portion group arranged between the first straight line portion group and the second straight line portion group and including a plurality of first intermediate straight line portions; a second intermediate straight portion group arranged between the first intermediate straight portion group and the second straight portion group and consisting of a plurality of second intermediate straight portions; may further comprise Adjacent ends of the first linear portion and the second linear portion may be connected via the first intermediate linear portion, Adjacent ends of the first intermediate straight portion and the second straight portion may be connected via the second intermediate straight portion.

[0039] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed by the first linear portion and the first intermediate linear portion may be 140° to 160°, When viewed in the axial direction, the angle formed by the first intermediate straight portion and the second intermediate straight portion may be 140° to 160°, When viewed in the axial direction, the angle formed between the second intermediate straight portion and the second straight portion may be 140° to 160°.

[0040] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed by the first linear portion and the first intermediate linear portion may be 150°, When viewed in the axial direction, the angle formed by the first intermediate straight portion and the second intermediate straight portion may be 150°, When viewed in the axial direction, the angle formed between the second intermediate straight portion and the second straight portion may be 150°.

[0041] In the coil unit according to the first aspect of the present invention, The coil elements may have an overall dodecagonal shape.

[0042] In the coil unit according to the first aspect of the present invention, The coil elements may have an overall regular dodecagonal shape.

[0043] In the coil unit according to the first aspect of the present invention, The first shield member may have a gap extending linearly between adjacent shield pieces, which gap crosses at least a portion of the first intermediate straight section group or at least a portion of the second intermediate straight section group when viewed in the axial direction.

[0044] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed by the gap and the at least a portion of the first group of intermediate straight portions or the at least a portion of the second group of intermediate straight portions may be 80° to 100°.

[0045] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the gap may be perpendicular to the at least part of the first group of intermediate straight portions or the at least part of the second group of intermediate straight portions.

[0046] In the coil unit according to the first aspect of the present invention, The first shield member may be formed with a gap that extends linearly between adjacent shield pieces and crosses at least a part of the coil element when viewed in the axial direction, and the gap may cross at least a part of a plurality of turn portions that form the coil element when viewed in the axial direction, When viewed in the axial direction, at a point where the gap and the turn portion intersect, the angle formed by the gap and the turn portion or a tangent to the turn portion may be 80° to 100°.

[0047] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, at a point where the gap and the turn portion intersect, the gap may be perpendicular to the turn portion or a tangent to the turn portion.

[0048] The coil unit according to the first invention may further include a first connection terminal connected to the coil, The coil may have an inner end proximate the central axis and an outer end distal to the central axis; The first connection terminal may be connected to the inner end portion and extend from the inner side to the outer side of the coil, The first shield member may have a gap extending linearly between adjacent shield pieces, the gap extending from the inside to the outside of the coil, When viewed in the axial direction, the first connection terminal may extend within the gap or within a notch formed in the shield piece.

[0049] In the coil unit according to the first aspect of the present invention, In a side view of the coil unit, the first connection terminal may extend from the inside to the outside of the coil at a height position where it overlaps with the shield piece.

[0050] In the coil unit according to the first aspect of the present invention, The coil element may have a plurality of turn portions arranged in a radial direction, When viewed in the axial direction, at a point where the first connection terminal intersects with each turn portion, the angle formed by the first connection terminal and the turn portion or a tangent to the turn portion may be 80° to 100°.

[0051] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, at a point where the first connection terminal intersects with each turn portion, the first connection terminal may be perpendicular to the turn portion or a tangent to the turn portion.

[0052] In the coil unit according to the first aspect of the present invention, The coil element may further include a group of straight line portions each including a plurality of straight line portions arranged in a radial direction and extending in the same direction, When viewed in the axial direction, the first connection terminal may intersect with the group of straight line portions.

[0053] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed between the first connection terminal and the group of straight line portions may be 80° to 100°.

[0054] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the first connection terminal may be perpendicular to the group of straight line portions.

[0055] In the coil unit according to the first aspect of the present invention, The coil element may further include a group of curved portions consisting of a plurality of curved portions arranged in a radial direction and extending parallel to each other, When viewed in the axial direction, the first connection terminal may intersect with the group of curved portions.

[0056] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the angle formed between the first connection terminal and a tangent to the group of curved portions may be 80° to 100°.

[0057] In the coil unit according to the first aspect of the present invention, When viewed in the axial direction, the first connection terminal may be perpendicular to a tangent to the group of curved portions.

[0058] In the coil unit according to the first aspect of the present invention, A point where the first connection terminal and an outer circumferential edge of the first shield member overlap as viewed in the axial direction may be defined as a first point, A point where a second connection terminal connected to the outer end portion and an outer circumferential edge of the first shield member overlap may be defined as the second point, as viewed in the axial direction; When viewed in the axial direction, the angle formed by a first virtual line connecting the first point and the central axis and a second virtual line connecting the second point and the central axis may be 90° or less.

[0059] In the coil unit according to the first aspect of the present invention, The angle formed between the first virtual line and the second virtual line may be 45° or less.

[0060] In the coil unit according to the first aspect of the present invention, A point where the first connection terminal and an outer circumferential edge of the first shield member overlap as viewed in the axial direction may be defined as a first point, A point where a second connection terminal connected to the outer end portion and an outer circumferential edge of the first shield member overlap may be defined as the second point, as viewed in the axial direction; The distance between the first point and the second point may be 100 mm or less.

[0061] In the coil unit according to the first aspect of the present invention, The distance between the first point and the second point may be 50 mm or less.

[0062] The coil unit according to the first aspect of the present invention may further include a second connection terminal connected to the coil, When viewed in the axial direction, the second shielding member may have a rectangular shape, and the first connection terminal and the second connection terminal may extend from the same side of the second shielding member.

[0063] In the coil unit according to the first aspect of the present invention, The coil element may be wound around the central axis in a first winding direction from an outer end to an inner end thereof, The outer end may be offset from the inner end in the first orbital direction.

[0064] In the coil unit according to the first aspect of the present invention, The coil element may include a first turn portion including the inner end portion, a second turn portion adjacent to the first turn portion in the radial direction and disposed radially outward from the first turn portion, and a third turn portion adjacent to the second turn portion in the radial direction and disposed radially outward from the second turn portion, The distance between the inner end portion and the second turn portion may be greater than the distance between the second turn portion and the third turn portion.

[0065] A power transmitting device according to a first aspect of the present invention includes the coil unit according to the first aspect of the present invention.

[0066] A power receiving device according to a first aspect of the present invention includes the coil unit according to the first aspect of the present invention.

[0067] The power transmission system according to the first invention comprises: The power transmission device includes a power receiving device. At least one of the power transmitting device and the power receiving device includes the coil unit according to the first aspect of the present invention.

[0068] A moving body according to a first aspect of the present invention includes the coil unit according to the first aspect of the present invention.

[0069] According to the first aspect of the present invention, the dimensions of the coil unit can be reduced.

[0070] <Second Invention> A second object of the present invention is to achieve efficient power transmission.

[0071] A coil unit according to a second aspect of the present invention includes a coil including coil elements formed in a spiral shape around a central axis, When viewed axially, the coil elements have a generally octagonal shape.

[0072] In the coil unit according to the second invention, The coil element may include seven straight line segments extending along seven of eight sides of an octagon; The angle formed by the adjacent groups of straight line portions may be 125° to 145°.

[0073] In the coil unit according to the second invention, The angle formed between adjacent groups of straight line portions may be 135°.

[0074] In the coil unit according to the second invention, The coil element may have an overall regular octagonal shape.

[0075] Alternatively, a coil unit according to a second aspect of the present invention includes a coil including coil elements formed in a spiral shape around a given central axis, When viewed in the axial direction, the coil elements have an overall dodecagonal shape.

[0076] In the coil unit according to the second invention, The coil element may include 11 straight line segments extending along 11 of the 12 sides of a dodecagon; The angle formed between adjacent groups of straight line portions may be 140° to 160°.

[0077] In the coil unit according to the second invention, The angle formed between adjacent groups of straight line portions may be 150°.

[0078] In the coil unit according to the second invention, The coil elements may have an overall regular dodecagonal shape.

[0079] The coil unit according to the second invention may further include a first shield member, The first shield member may be divided into a plurality of shield pieces, The first shield member may have a gap formed therein that extends linearly between adjacent shield pieces, The coil element may include a group of straight line portions each including a plurality of straight line portions arranged in a radial direction and extending in the same direction, When viewed in the axial direction, the gap may traverse at least a portion of the group of straight line portions.

[0080] In the coil unit according to the second invention, When viewed in the axial direction, the angle formed between the gap and the at least part of the group of straight line portions may be 80° to 100°.

[0081] In the coil unit according to the second invention, When viewed in the axial direction, the gap may be perpendicular to the at least some of the straight line portions.

[0082] A power transmitting device according to a second aspect of the present invention includes the coil unit according to the second aspect of the present invention.

[0083] A power receiving device according to a second aspect of the present invention includes the coil unit according to the second aspect of the present invention.

[0084] The power transmission system according to the second invention comprises: The power transmission device includes a power receiving device. At least one of the power transmitting device and the power receiving device includes the coil unit according to the second aspect of the present invention.

[0085] A moving body according to a second aspect of the present invention includes the coil unit according to the second aspect of the present invention.

[0086] According to the second aspect of the present invention, efficient power transmission can be achieved. [Brief explanation of the drawings]

[0087] [Figure 1] FIG. 1 is a diagram schematically illustrating a wireless power transmission system to which a coil unit according to an embodiment can be applied. [Figure 2] FIG. 2 is a perspective view of a coil unit used in the wireless power transmission system shown in FIG. [Figure 3] FIG. 3 is an exploded perspective view of the coil unit shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the coil unit taken along line IV-IV in FIG. [Figure 5A] FIG. 5A is a plan view of the coil unit shown in FIG. [Figure 5B] FIG. 5B is a diagram illustrating the coil unit shown in FIG. 5A, showing a first point, a second point, a first virtual line, and a second virtual line. [Figure 6A] FIG. 6A is a diagram corresponding to FIG. 5A, showing a modified coil unit. [Figure 6B] FIG. 6B is a diagram showing the first point, the second point, the first virtual line, and the second virtual line of the coil unit shown in FIG. 6A. [Figure 7] FIG. 7 is a cross-sectional view of the coil unit taken along line VII-VII in FIG. 6A. [Figure 8] FIG. 8 is a diagram corresponding to FIG. 5A, showing another modified example of the coil unit. [Figure 9] FIG. 9 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 10] FIG. 10 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 11]FIG. 11 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 12] FIG. 12 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 13] FIG. 13 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 14] FIG. 14 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 15] FIG. 15 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 16] FIG. 16 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 17] FIG. 17 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 18] 18 is a cross-sectional view of the coil unit taken along line XVIII-XVIII in FIG. [Figure 19] FIG. 19 is an exploded perspective view of the coil shown in FIG. [Figure 20] FIG. 20 is a view corresponding to FIG. 17, showing yet another modified example of the coil unit. [Figure 21] FIG. 21 is a view corresponding to FIG. 17, showing yet another modified example of the coil unit. [Figure 22] FIG. 22 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 23] FIG. 23 is a diagram corresponding to FIG. 17, showing yet another modified example of the coil unit. [Figure 24] FIG. 24 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 25] FIG. 25 is a view corresponding to FIG. 17, showing yet another modified example of the coil unit. [Figure 26]FIG. 26 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 27] FIG. 27 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 28] FIG. 28 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 29] FIG. 29 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 30] FIG. 30 is a view corresponding to FIG. 17, showing yet another modified example of the coil unit. [Figure 31] FIG. 31 is a view corresponding to FIG. 17, showing yet another modified example of the coil unit. [Figure 32] FIG. 32 is a view corresponding to FIG. 17, showing yet another modified example of the coil unit. [Figure 33] FIG. 33 is a view corresponding to FIG. 17, showing yet another modified example of the coil unit. [Figure 34] FIG. 34 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 35] FIG. 35 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 36] FIG. 36 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 37] FIG. 37 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 38] FIG. 38 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 39] FIG. 39 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 40] FIG. 40 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 41] FIG. 41 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 42] FIG. 42 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 43] FIG. 43 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 44] FIG. 44 is a view corresponding to FIG. 17, showing yet another modified example of the coil unit. [Figure 45] FIG. 45 is a diagram corresponding to FIG. 5A, showing yet another modified example of the coil unit. [Figure 46] FIG. 46 is a table showing the Q values and losses of the coil units of Examples 1-1 to 1-7. [Figure 47] FIG. 47 is a table showing the Q values and losses of the coil units of Example 2 and Comparative Examples 2-1 to 2-4. [Figure 48] FIG. 48 is a table showing the evaluation results of the coil unit of Example 3. [Figure 49] FIG. 49 is a table showing the evaluation results of the coil unit of Example 4. [Figure 50] FIG. 50 is a table showing the comparison results between the coil units of Example 3 and Example 4. [Figure 51] FIG. 51 is a table showing the evaluation results of the coil unit of Example 5. [Figure 52] FIG. 52 is a table showing the evaluation results of the coil unit of Example 6. [Figure 53] FIG. 53 is a table showing the comparison results between the coil units of Example 5 and Example 6. [Figure 54] FIG. 54 is a table showing the Q value of the coil unit of Example 7. [Figure 55] FIG. 55 is a table showing the comparison results of the Q values of the coil units of Example 7. [Figure 56] FIG. 56 corresponds to FIG. 17 and is a diagram for explaining the eighth embodiment. [Figure 57] FIG. 57 is a diagram for explaining the shape of the coil of the coil unit of Example 8-1. [Figure 58] FIG. 58 is a diagram for explaining the shape of the coil of the coil unit of Example 8-2. [Figure 59] FIG. 59 is a diagram for explaining the shape of the coil of the coil unit of Example 8-3. [Figure 60] FIG. 60 is a diagram for explaining the shape of the coil of the coil unit of Example 8-4. [Figure 61] FIG. 61 is a graph showing the Q values of the coil units of Examples 8-1 to 8-4. [Figure 62] FIG. 62 is a graph showing the coupling coefficients of the coil units of Examples 8-1 to 8-4. [Figure 63] FIG. 63 is a graph showing the product of the coupling coefficient and the Q value of the coil units of Examples 8-1 to 8-4. DETAILED DESCRIPTION OF THE INVENTION

[0088] Hereinafter, each embodiment will be described with reference to the drawings. In the drawings attached to this specification, the scale and aspect ratios of the actual objects have been appropriately changed and exaggerated for the sake of ease of illustration and understanding.

[0089] Furthermore, in this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely based on differences in names. Therefore, for example, "sheet" is a concept that also includes members that can be called films or plates.

[0090] In addition, in this specification, the term "sheet surface (plate surface, film surface)" refers to a surface that coincides with the planar direction (face direction) of the target sheet-like (plate, film) member when the target sheet-like (plate, film) member is viewed overall and in a broad perspective. Furthermore, in this specification, the normal direction of the sheet-like (plate, film) member refers to the normal direction to the sheet surface (plate surface, film surface) of the target sheet-like (plate, film) member.

[0091] <Wireless power transmission system> 1 schematically shows a wireless power transmission system S to which a coil unit according to an embodiment described later can be applied. First, the wireless power transmission system S (hereinafter abbreviated as power transmission system S) will be described with reference to FIG.

[0092] The power transmission system S includes a power transmitting device 1 and a power receiving device 2. The power transmitting device 1 includes a coil unit 5 and a high-frequency current supply unit 1A. The coil unit 5 in the power transmitting device 1 functions as a power transmitting coil unit. The high-frequency current supply unit 1A supplies a high-frequency current to the coil unit 5 serving as a power transmitting coil unit.

[0093] The power receiving device 2 includes a coil unit 5 and a conversion unit 2A. The coil unit 5 in the power receiving device 2 functions as a power receiving coil unit. The conversion unit 2A shapes the high-frequency current generated in the coil unit 5. The conversion unit 2A includes a rectifier circuit that converts the high-frequency current into a direct current.

[0094] 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 unit 5 serving as a power transmitting coil unit. At this time, a magnetic field is generated in the coil unit 5 due to electromagnetic induction. Then, due to the influence of this magnetic field, a high-frequency current is generated in the coil unit 5 serving as a power receiving coil unit in the power receiving device 2. 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).

[0095] The power transmission system S shown in Fig. 1 employs a magnetic resonance method as a power transmission method. However, the power transmission system S may also be configured as an electromagnetic induction type power transmission system. Here, an example will be described in which 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.

[0096] 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 drones and other flying objects, or robots. The power transmission system S may also be used to transmit power to underwater submersibles and exploration robots. 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 unit according to the embodiment is not limited to wireless power transmission systems. For example, the coil unit according to the embodiment may be used in a transformer, a DC-DC converter, an antenna, etc.

[0097] Each power transmission system S includes, as the coil unit 5, any of the coil units 5 according to the first and second embodiments and their modified examples, which will be described later. The same coil unit 5 may be used in each of the power transmitting device 1 and the power receiving device 2. Alternatively, different coil units 5 may be used in each of the power transmitting device 1 and the power receiving device 2. Alternatively, the coil unit 5 according to the first and second embodiments and their modified examples may be used in one of the power transmitting device 1 and the power receiving device 2, and a coil unit of another type may be used in the other. The coil units 5 according to the first and second embodiments and their modified examples will be described below.

[0098] <<First embodiment>> A first embodiment of the present invention will be described below with reference to the drawings.

[0099] <Coil unit> Fig. 2 is a perspective view of the coil unit 5 according to the first embodiment. Fig. 3 is an exploded perspective view of the coil unit 5. Fig. 4 is a cross-sectional view of the coil unit 5 taken along line IV-IV in Fig. 2. Figs. 5A and 5B are plan views of the coil unit 5. A first connection terminal 46 and a second connection terminal 47, which will be described later, are not shown in Figs. 3 and 5A.

[0100] 2 to 4, the coil unit 5 includes a coil 10, a magnetic resin layer 20, a first shielding member 30, and a second shielding member 40. In the illustrated example, the coil unit 5 further includes a first connection terminal 46 and a second connection terminal 47. As shown in FIG. 2, the first connection terminal 46 and the second connection terminal 47 are connected to one end 10e1 and the other end 10e2 of the coil 10, respectively.

[0101] As shown in Fig. 4, the coil 10 has a first main surface 10a and a second main surface 10b. The second main surface 10b is the surface opposite to the first main surface 10a. The coil 10, the magnetic resin layer 20, the first shield member 30, and the second shield member 40 are arranged in this order in the direction from the first main surface 10a toward the second main surface 10b. Hereinafter, the terms "first side" and "second side" used for the coil unit 5 and its components refer to the side toward which the first main surface 10a faces and the side toward which the second main surface 10b faces, respectively.

[0102] (coil) As shown in FIG. 5A, the coil 10 includes coil elements 10i formed in a spiral shape around an arbitrary central axis C. A spiral shape refers to the shape of a planar curve that moves away from the center as it turns (or moves closer to the center as it turns). The planar curve referred to here also includes a planar pattern that is bent like a broken line. In the illustrated embodiment, the spiral shape is located on an imaginary plane perpendicular to the central axis. The coil elements 10i are formed from a conductive material. In this embodiment, the coil elements 10i are formed from copper, but are not limited to this. The coil elements 10i may also be formed from other conductive materials such as copper alloys, aluminum, and aluminum alloys.

[0103] In the example shown in Figures 2 to 5B, the coil 10 is composed of a single coil element 10i. The coil element 10i is plate-shaped. That is, the coil element 10i is a planar coil. More specifically, the coil element 10i is a planar coil element made of non-litz wire. As shown in Figure 4, the cross section of the conductor of the coil element 10i in a direction perpendicular to the winding direction of the spiral shape is rectangular.

[0104] The symbol C shown in Figures 2 to 5B indicates the central axis of the coil element 10i (or the coil 10) that passes through the center of the spiral shape of the coil element 10i. Hereinafter, the axial direction means a direction extending on the central axis C or a direction parallel to the central axis C. Furthermore, the radial direction means a radial direction of a circle centered on the central axis C. Furthermore, the circumferential direction means a direction along a circle centered on the central axis C (a circumferential direction of the circle).

[0105] The coil element 10i includes a conductor 10E having a spiral shape. The conductor 10E includes a plurality of turn portions 101 to 108 arranged in the radial direction. In the illustrated example, the conductor 10E includes first to eighth turn portions 101 to 108. The first to eighth turn portions 101 to 108 are arranged in this order from the inside to the outside in the radial direction. In other words, the first turn portion 101 is located at the innermost position in the radial direction, and the eighth turn portion 108 is located at the outermost position in the radial direction. In yet other words, the first turn portion 101 forms the innermost portion of the coil element 10i. The eighth turn portion 108 forms the outermost portion of the coil element 10i. Note that "inward in the radial direction of a certain member" means a position closer to the central axis C than that member. Note that "outward in the radial direction of a certain member" means a position farther outward in the radial direction than that member. For example, when we say "radially inward of the coil element 10i," this means a position closer to the central axis C than the innermost turn portion 101. When we say "radially outward of the coil element 10i," this means a position farther outward in the radial direction than the outermost turn portion 108.

[0106] Each of the turn portions 101 to 108 extends on the above-mentioned imaginary plane. The first to eighth turn portions 101 to 108 are connected in this order, thereby forming the coil element 10i in a spiral shape. In the illustrated example, the coil element 10i (electrical conductor 10E) is wound so that each of the turn portions 101 to 108 forms a substantially rectangular shape, but this is not limited thereto. Each of the turn portions 101 to 108 may also be wound so as to form a substantially polygonal shape other than a rectangular shape.

[0107] One end of each of the turn portions 101 to 108 is located radially inward from the other end of the corresponding turn portion 101 to 108. In other words, the other end of each of the turn portions 101 to 108 is located radially outward from the one end of the corresponding turn portion 101 to 108.

[0108] Each of the turn portions 101 to 108 includes a plurality of straight portions 11 to 14 arranged around the central axis C. The straight portions 11 to 14 adjacent in the circumferential direction of a circle centered on the central axis C are connected to each other. In the illustrated example, the straight portions adjacent in the circumferential direction are connected via first intermediate curved portions 151 to 154 that curve along the circumferential direction. In the illustrated example, the first to eighth turn portions 101 to 108 include a first straight portion 11 and a third straight portion 13 that extend in a first direction D1, and a second straight portion 12 and a fourth straight portion 14 that extend in a second direction D2. The first direction D1 and the second direction D2 are not parallel to each other. In the illustrated example, the first direction D1 and the second direction D2 are perpendicular to each other. In each of the turn portions 101 to 108, the first straight portion 11 and the third straight portion 13 are arranged so that the central axis C passes therebetween. In each of the turn sections 101 to 108, the second straight section 12 and the fourth straight section 14 are arranged so that the central axis C passes therebetween. In each of the turn sections 101 to 108, adjacent ends of the first straight section 11 and the second straight section 12 are connected via a 1A intermediate curve section 151. Similarly, in each of the turn sections 101 to 108, adjacent ends of the second straight section 12 and the third straight section 13 are connected via a 1B intermediate curve section 152. In each of the turn sections 101 to 108, adjacent ends of the third straight section 13 and the fourth straight section 14 are connected via a 1C intermediate curve section 153.

[0109] Furthermore, adjacent ends of the fourth straight portion 14 and the first straight portion 11 of radially adjacent turn portions 101, 102;...; 107, 108 are connected via a 1D intermediate curve portion 154. For example, adjacent ends of the fourth straight portion 14 of the first turn portion 101 and the first straight portion 11 of the second turn portion 102 are connected via a 1D intermediate curve portion 154. Also, adjacent ends of the fourth straight portion 14 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103 are connected via a 1D intermediate curve portion 154. As shown in FIG. 2 , a first connection terminal 46 is connected to the first straight portion 11 of the first turn portion 101, which is located in the innermost position. A second connection terminal 47 is connected to the fourth straight portion 14 of the eighth turn portion 108, which is located in the outermost position.

[0110] The first straight line portions 11 of the plurality of turn portions 101-108 are arranged in the radial direction to form a first straight line portion group 11G. The second straight line portions 12 of the plurality of turn portions 101-108 are arranged in the radial direction to form a second straight line portion group 12G. The third straight line portions 13 of the plurality of turn portions 101-108 are arranged in the radial direction to form a third straight line portion group 13G. The fourth straight line portions 14 of the plurality of turn portions 101-108 are arranged in the radial direction to form a fourth straight line portion group 14G. The radially adjacent straight line portions 11,11; 12,12; 13,13; 14,14 are spaced apart from each other in the radial direction. The first to fourth straight line portion groups 11G-14G are groups of parallel straight lines each made up of a plurality of first to fourth straight line portions 11-14.

[0111] The first A intermediate curved portions 151 of the plurality of turn portions 101-108 are arranged in the radial direction to form a first A intermediate curved portion group 151G. The first B intermediate curved portions 152 of the plurality of turn portions 101-108 are arranged in the radial direction to form a first B intermediate curved portion group 152G. The first C intermediate curved portions 153 of the plurality of turn portions 101-108 are arranged in the radial direction to form a first C intermediate curved portion group 153G. The first D intermediate curved portions 154 of the plurality of turn portions 101-108 are arranged in the radial direction to form a first D intermediate curved portion group 154G. The radially adjacent first intermediate curved portions 151, 151; 152, 152; 153, 153; 154, 154 are radially spaced apart from each other. The 1A to 1D intermediate curved line groups 151G to 154G are groups of parallel curved lines made up of a plurality of 1A to 1D intermediate curved line groups 151 to 154, respectively.

[0112] 2 to 5B, the pitches of the plurality of turn portions 101 to 108 are equal. Therefore, the distance between the first turn portion 101 and the second turn portion 102 is equal to the distance between the second turn portion 102 and the third turn portion 103. Furthermore, in each of the straight portion groups 11G to 14G, the pitches of the plurality of straight portions 11 to 14 are equal. Therefore, the distance between the first straight portion 11 of the first turn portion 101 and the first straight portion 11 of the second turn portion 102 is equal to the distance between the first straight portion 11 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103. Furthermore, in each of the first intermediate curve portion groups 151G to 154G, the pitches of the plurality of first intermediate curve portions 151 to 154 are equal. Therefore, the distance between the first intermediate curved portion 151 of the first turn portion 101 and the first intermediate curved portion 151 of the second turn portion 102 is equal to the distance between the first intermediate curved portion 151 of the second turn portion 102 and the first intermediate curved portion 151 of the third turn portion 103.

[0113] The coil element 10i described above is formed, for example, by punching a metal plate such as a copper plate into a spiral shape. Alternatively, the coil element 10i can also be formed by etching a metal foil such as a copper foil into a spiral shape. In this case, the coil element 10i can be formed into a complex spiral pattern. However, etching requires time and effort to ensure that the coil element 10i is thick enough to transmit high power. Therefore, punching is preferable from the viewpoint of manufacturing efficiency.

[0114] The thickness of the conductor 10E in the coil element 10i may be, for example, 0.2 mm or more and 1.0 mm or less. The radius of the coil element 10i (the distance from the central axis C to the radially most distant part) may be 200 mm or more. When the coil 10 is used in a power transmitting coil unit or a power receiving coil unit of a power transmission system S that transmits power to an electric vehicle using a magnetic field resonance method, the radius of the coil element 10i (the distance from the central axis C to the radially most distant part) is typically 200 mm or more and 350 mm or less. In this embodiment, the coil element 10i has a rectangular shape as a whole. In this case, the maximum longitudinal dimension of the coil element 10i may be 300 mm or more and 700 mm or less, and the maximum transverse dimension perpendicular to the longitudinal direction may be 200 mm or more and 650 mm or less. For example, when the coil 10 is used in a power transmitting coil unit, the longitudinal dimension of the coil element 10i may be 550 mm or more and 700 mm or less, and the transverse dimension of the coil element 10i may be 400 mm or more and 550 mm or less. When the coil 10 is used in a power receiving coil unit, the longitudinal dimension of the coil element 10i may be 350 mm or more and 500 mm or less, and the transverse dimension of the coil element 10i may be 200 mm or more and 350 mm or less.

[0115] Furthermore, when transmitting power to an electric vehicle using the magnetic resonance method, it is desirable to be able to transmit 1 kW or more, preferably 5 kW or more, of power in the high-frequency current frequency range of 10 kHz to 200 kHz, particularly 79 kHz to 90 kHz. In this case, the thickness of the coil element 10i made of copper is preferably 0.4 mm or more. However, if the thickness of the coil element 10i is too large, the weight of the coil 10 increases, which is undesirable for, for example, on-board installation. Therefore, the thickness of the coil element 10i may be, for example, 2.0 mm or less, 1.5 mm or less, or 1.0 mm or less.

[0116] The line width of the conductor 10E in the coil element 10i 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 range of, for example, 79 kHz to 90 kHz, the line width of each turn portion 101 to 108 may be 2 mm to 20 mm, 2 mm to 16 mm, 2 mm to 12 mm, or 2 mm to 8 mm. Note that the line width refers to the distance between the inner and outer peripheral surfaces of the conductor 10E in a cross section perpendicular to the direction in which the conductor 10E turns.

[0117] In this specification, the central axis C of the spiral shape described above is defined as follows. First, linear imaginary turn sections similar in shape to the innermost turn section 101 are drawn sequentially from the radially inner end of the innermost turn section 101 in a spiral shape extending radially inward. Drawing is continued until imaginary turn sections that fit within a diameter of 1 cm are drawn. Then, a line that passes radially inward of the imaginary turn sections that fit within a diameter of 1 cm, in a direction perpendicular to the circumferential and radial directions of the spiral shape, is defined as the central axis C.

[0118] The coil 10 has an end 10e1 to which the first connection terminal 46 is connected and an end 10e2 to which the second connection terminal 47 is connected. In the illustrated example, the coil 10 is composed of a single coil element 10i. Therefore, one end 10e1 is an inner end located radially inward of the coil 10. The other end 10e2 is an outer end located radially outward of the coil 10. The inner end 10e1 is an end of the first turn portion 101 of the coil element 10i. The outer end 10e2 is an end of the eighth turn portion 108 of the coil element 10i.

[0119] (Magnetic resin layer) The magnetic substance resin layer 20 is provided to suppress magnetic permeation and / or leakage magnetic field. The magnetic substance resin layer 20 overlaps the coil 10 in the axial direction of the coil 10. In this state, the magnetic substance resin layer 20 is in direct contact with the second main surface 10b of the coil 10. In other words, the magnetic substance resin layer 20 is in direct contact with the conductor 10E. In the illustrated example, the magnetic substance resin layer 20 is in close contact with the second main surface 10b of the coil 10. In other words, the magnetic substance resin layer 20 is in close contact with the conductor 10E. The magnetic substance resin layer 20 covers the second main surface 10b. More specifically, the magnetic substance resin layer 20 is formed so that its outer peripheral edge is located outside the coil 10 when viewed in the axial direction.

[0120] The magnetic resin layer 20 is magnetic. The magnetic field generated in the coil unit 5 spreads in all directions relative to the central axis C of the coil 10. In this case, the magnetic resin layer 20 is magnetic, so that the spreading magnetic flux lines can be oriented toward the central axis C. Furthermore, if the magnetic field generated in the coil unit 5 reaches peripheral components located around the coil unit 5, it may adversely affect the peripheral components. For this reason, the magnetic resin layer 20 is provided to prevent the magnetic lines of force from reaching the peripheral components. As a result, the magnetic resin layer 20 can suppress leakage magnetic fields that do not contribute to the generation of current.

[0121] The magnetic resin layer 20 includes a magnetic material. The magnetic resin layer 20 preferably includes a soft magnetic material. More specifically, the magnetic resin layer 20 includes ferrite, preferably soft ferrite. The magnetic resin layer 20 may also include a nanocrystalline magnetic material.

[0122] The magnetic substance resin layer 20 also contains a resin. For example, a thermosetting resin such as an epoxy resin or polyimide can be used as the resin for forming the magnetic substance resin layer 20. In this case, when the coil 10 and the magnetic substance resin layer 20 are integrated by heat pressing as described below, the resin of the magnetic substance resin layer 20 can be easily deformed to conform to the shape of the coil 10 during the heat curing process. Furthermore, a thermoplastic resin such as nylon can also be used as the resin for forming the magnetic substance resin layer 20. In this case, too, the resin of the magnetic substance resin layer 20 can be easily deformed to conform to the shape of the coil 10.

[0123] As shown in FIGS. 2 and 4, the magnetic resin layer 20 has a spiral-shaped recess 25 that corresponds to the spiral shape of the coil 10. The recess 25 is a portion of the magnetic resin layer 20 that is recessed in the axial direction of the coil 10, in other words, in the thickness direction of the magnetic resin layer 20. The recess 25 has a spiral shape when viewed in the axial direction of the coil 10. At least a portion of the coil 10 is housed in the recess 25 with its spiral shape aligned with the spiral shape of the recess 25. More specifically, the recess 25 houses the entire conductor 10E. Therefore, as shown in FIG. 4, the magnetic resin layer 20 is in direct contact with three surfaces of the coil 10 other than the first main surface 10a.

[0124] In this embodiment, the conductor 10E does not protrude from the magnetic substance resin layer 20. In other words, the first main surface 10a of the coil 10 and the surface of the magnetic substance resin layer 20 facing the first side are flush with each other. However, only a portion of the coil 10 may be housed in the recess 25 so that a portion of the coil 10 protrudes from the magnetic substance resin layer 20. Alternatively, the recess 25 may not be formed in the magnetic substance resin layer 20, and the coil 10 may be provided on the flat surface of the magnetic substance resin layer 20. Alternatively, the conductor 10E may be embedded in the magnetic substance resin layer 20 without being exposed to the outside.

[0125] As described above, in the illustrated example, the magnetic substance resin layer 20 is in close contact with the second main surface 10b of the coil 10. Specifically, the magnetic substance resin layer 20 is welded to the coil 10 at the recess 25. That is, the coil 10 and the magnetic substance resin layer 20 are joined at the recess 25 by the anchor effect. The coil 10 and the magnetic substance resin layer 20 are integrated together by, for example, heat pressing. At this time, part of the magnetic substance resin layer 20 enters the recess on the surface of the coil 10 and then hardens. As a result, the coil 10 and the magnetic substance resin layer 20 are welded together, and the magnetic substance resin layer 20 is in close contact with the coil 10.

[0126] In the illustrated example, the magnetic substance resin layer 20 is divided into a plurality of pieces, similar to the first shield member 30 described later. The magnetic substance resin layer 20 includes a plurality of magnetic substance resin elements 21-24. In the illustrated example, the magnetic substance resin layer 20 includes first to fourth magnetic substance resin elements 21-24. Gaps extending linearly between adjacent magnetic substance resin elements 21, 22; 22, 23; 23, 24; 24, 21 are formed in the magnetic substance resin layer 20. In the illustrated example, the gaps extending between the magnetic substance resin elements 21-24 coincide with gaps 51-54 extending between shield pieces 31-34 described later when viewed in the axial direction. Note that the magnetic substance resin layer 20 does not have to be divided into a plurality of magnetic substance resin elements 21-24. In other words, the magnetic substance resin layer 20 does not have to have gaps formed therein.

[0127] (First shielding member) The first shield member 30 is provided to suppress magnetic transmission and / or leakage magnetic field. The first shield member 30 is formed in a plate shape and extends along a plane perpendicular to the axial direction of the coil 10. The first shield member 30 is sized so that its outer periphery is positioned outside the magnetic resin layer 20 and the coil 10 when viewed in the axial direction. The first shield member 30 is provided between the second shield member 40 and the coil 10 and magnetic resin layer 20.

[0128] The first shield member 30 includes a magnetic material. As described above, the magnetic field generated by the coil unit 5 spreads in all directions relative to the central axis C of the coil 10. In this case, the first shield member 30 is magnetic, and thus can direct the spreading magnetic flux lines toward the central axis C. The first shield member 30 is also provided to prevent magnetic lines from reaching surrounding components. This allows the first shield member 30 to suppress leakage magnetic fields that do not contribute to the generation of current.

[0129] The first shield member 30 preferably includes a soft magnetic material. More specifically, the first shield member 30 includes a ferrite, preferably a soft ferrite. The first shield member 30 may also include a nanocrystalline magnetic material.

[0130] In the example shown in FIG. 4 , the first shield member 30 is disposed at a distance from the magnetic substance resin layer 20, but this is not limiting. The first shield member 30 may be in contact with the magnetic substance resin layer 20. When the first shield member 30 is disposed at a distance from the magnetic substance resin layer 20, a spacer (not shown) may be disposed between the first shield member 30 and the magnetic substance resin layer 20. This allows the distance between the first shield member 30 and the magnetic substance resin layer 20 to be maintained at a predetermined distance. The distance between the first shield member 30 and the magnetic substance resin layer 20 is not particularly limited, but is, for example, 3 mm or less. Note that the longer the distance between the first shield member 30 and the magnetic substance resin layer 20, the more difficult it is for heat to be dissipated from the coil unit 5, which may result in the coil unit 5 becoming too hot. For this reason, the distance between the first shield member 30 and the magnetic substance resin layer 20 is preferably 1 mm or less. The distance between the first shield member 30 and the magnetic substance resin layer 20 may be 0 mm. In other words, the first shield member 30 and the magnetic resin layer 20 may be in direct contact or in close contact with each other. Reducing the distance between the first shield member 30 and the magnetic resin layer 20 is also preferable for reducing the dimensions of the coil unit 5 (particularly the dimensions along the axial direction).

[0131] The first shielding member 30 is dimensioned so that its outer periphery is located outside the coil 10 in the axial direction. Here, in the case of a coil 10 used in a power transmitting coil unit or a power receiving coil unit of a power transmission system S that transmits power to an electric vehicle as described above, the dimensions of the coil 10 in the axial direction (longitudinal dimension × lateral dimension) are typically 200 mm or more × 200 mm or more. Therefore, in this case, the outer dimensions of the first shielding member 30 are also 200 mm or more × 200 mm or more. However, it may be difficult to realize a first shielding member 30 of such dimensions using a single plate. For example, if the first shielding member 30 is a ferrite plate, it is generally difficult to form a single ferrite plate whose longitudinal and lateral dimensions both exceed 150 mm. Even if it were possible to form a single ferrite plate whose longitudinal and lateral dimensions both exceed 150 mm, such a ferrite plate would be prone to cracking. If the first shield member 30 in the coil unit 5 is cracked, the performance of the coil unit 5 may be degraded.

[0132] Taking these points into consideration, the coil unit 5 of this embodiment is devised as described below. First, the first shield member 30 is divided into multiple shield pieces 30P. In other words, the first shield member 30 includes multiple shield pieces 30P arranged in the same plane. The dimensions of each shield piece 30P as viewed in the axial direction may be 150 mm or less × 150 mm or less. This makes it easier to form a large-sized first shield member 30 and also reduces the risk of individual shield pieces 30P cracking.

[0133] 2 to 5B, the first shielding member 30 includes first to fourth shielding pieces 31 to 34. Each of the shielding pieces 31 to 34 has a rectangular shape. In the illustrated example, each of the shielding pieces 31 to 34 includes ferrite. More specifically, each of the shielding pieces 31 to 34 is formed of a ferrite plate.

[0134] Gaps 50 are formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 31. The width of the gaps 50 is arbitrary, but considering the manufacturing tolerances of the shield pieces 31 to 34, the width of the gaps 50 is preferably 1 mm or more. The width of the gaps 50 may be 2 mm or more, 3 mm or more, or 4 mm or more. However, from the viewpoint of suppressing the transmission of magnetic lines of force through the gaps 50, the width of the gaps is preferably 6 mm or less.

[0135] In the illustrated example, a plurality of gaps 50 are formed in the first shielding member 30. Each gap 50 extends linearly. In the illustrated example, first to fourth gaps 51 to 54 are formed in the first shielding member 30.

[0136] The first gap 51 extends between the first shield piece 31 and the fourth shield piece 34 along the second direction D2. The first gap 51 crosses at least a portion of the first straight portion group 11G when viewed in the axial direction. In the example shown in FIG. 5A , the first gap 51 crosses the first straight portions 11 of the second to eighth turn portions 102 to 108 when viewed in the axial direction. In other words, the first gap 51 extends from a position radially inward of the second turn portion 102 to a position radially outward of the eighth turn portion 108 when viewed in the axial direction. By arranging the shield pieces 31 and 34 so that the first gap 51 crosses the first straight portions 11, magnetic field lines formed around each first straight portion 11 are prevented from reaching the second shield member 40 through the first gap 51. This prevents eddy currents from being generated in the second shield member 40 by magnetic field lines formed around the first straight portions 11. This means that it is possible to suppress an increase in loss (heat generation) of the coil unit 5 due to the presence of the first gap 51, and it is possible to suppress a decrease in performance of the cocoil unit 5 due to the presence of the first gap 51.

[0137] When viewed in the axial direction, the angle formed between the first gap 51 and the first linear portions 11 of the second to eighth turn portions 102 to 108 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the first gap 51 can be effectively suppressed, and a decrease in performance of the coil unit 5 due to the presence of the first gap 51 can be effectively suppressed. Furthermore, as can be seen from FIG. 5A , when viewed in the axial direction, the first gap 51 may be perpendicular to the first linear portions 11 of the second to eighth turn portions 102 to 108. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the first gap 51 can be more effectively suppressed, and a decrease in performance of the coil unit 5 due to the presence of the first gap 51 can be more effectively suppressed.

[0138] The second gap 52 extends between the first shield piece 31 and the second shield piece 32 along the first direction D1. The second gap 52 crosses at least a portion of the second straight portion group 12G when viewed in the axial direction. In the example shown in FIG. 5A , the second gap 52 crosses the second straight portions 12 of the first to eighth turn portions 101 to 108 when viewed in the axial direction. In other words, the second gap 52 extends from a position radially inward of the first turn portion 101 to a position radially outward of the eighth turn portion 108 when viewed in the axial direction. By arranging the shield pieces 31 and 32 so that the second gap 52 crosses the second straight portions 12, magnetic field lines formed around each second straight portion 12 are prevented from reaching the second shield member 40 through the second gap 52. This prevents eddy currents from being generated in the second shield member 40 by magnetic field lines formed around the second straight portions 12. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the second gap 52 can be suppressed, and that a decrease in performance of the coil unit 5 due to the presence of the second gap 52 can be suppressed.

[0139] When viewed in the axial direction, the angle formed between the second gap 52 and the second straight portions 12 of the first to eighth turn portions 101 to 108 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the second gap 52 can be effectively suppressed, and a decrease in performance of the coil unit 5 due to the presence of the second gap 52 can be effectively suppressed. Furthermore, as can be seen from FIG. 5A , when viewed in the axial direction, the second gap 52 may be perpendicular to the second straight portions 12 of the first to eighth turn portions 101 to 108. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the second gap 52 can be more effectively suppressed, and a decrease in performance of the coil unit 5 due to the presence of the second gap 52 can be more effectively suppressed.

[0140] The third gap 53 extends between the second shield piece 32 and the third shield piece 33 along the second direction D2. The third gap 53 crosses at least a portion of the third straight portion group 13G when viewed in the axial direction. In the example shown in FIG. 5A , the third gap 53 crosses the third straight portions 13 of the first to eighth turn portions 101 to 108 when viewed in the axial direction. In other words, the third gap 53 extends from a position radially inward of the first turn portion 101 to a position radially outward of the eighth turn portion 108 when viewed in the axial direction. By arranging the shield pieces 32, 33 so that the third gap 53 crosses the third straight portions 13, magnetic field lines formed around each third straight portion 13 are prevented from reaching the second shield member 40 through the third gap 53. This prevents eddy currents from being generated in the second shield member 40 by magnetic field lines formed around the third straight portions 13. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the third gap 53 can be suppressed, and that a decrease in performance of the coil unit 5 due to the presence of the third gap 53 can be suppressed.

[0141] When viewed in the axial direction, the angle formed between the third gap 53 and the third straight portions 13 of the first to eighth turn portions 101 to 108 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the third gap 53 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the third gap 53 can be effectively suppressed. Furthermore, as can be seen from FIG. 5A , when viewed in the axial direction, the third gap 53 may be perpendicular to the third straight portions 13 of the first to eighth turn portions 101 to 108. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the third gap 53 can be more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the third gap 53 can be more effectively suppressed.

[0142] The fourth gap 54 extends between the third shield piece 33 and the fourth shield piece 34 along the first direction D1. The fourth gap 54 crosses at least a portion of the fourth straight portion group 14G when viewed in the axial direction. In the example shown in FIG. 5A , the fourth gap 54 crosses the fourth straight portions 14 of the first to eighth turn portions 101 to 108 when viewed in the axial direction. In other words, the fourth gap 54 extends from a position radially inward of the first turn portion 101 to a position radially outward of the eighth turn portion 108 when viewed in the axial direction. By arranging the shield pieces 33, 34 so that the fourth gap 54 crosses the fourth straight portions 14, magnetic field lines formed around each fourth straight portion 14 are prevented from reaching the second shield member 40 through the fourth gap 54. This prevents eddy currents from being generated in the second shield member 40 by magnetic field lines formed around the fourth straight portions 14. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the fourth gap 54 can be suppressed, and that a decrease in performance of the coil unit 5 due to the presence of the fourth gap 54 can be suppressed.

[0143] When viewed in the axial direction, the angle formed between the fourth gap 54 and the fourth straight portions 14 of the first to eighth turn portions 101 to 108 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the fourth gap 54 can be effectively suppressed, and a decrease in performance of the coil unit 5 due to the presence of the fourth gap 54 can be effectively suppressed. Furthermore, as can be seen from FIG. 5A , when viewed in the axial direction, the fourth gap 54 may be perpendicular to the fourth straight portions 14 of the first to eighth turn portions 101 to 108. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the fourth gap 54 can be even more effectively suppressed, and a decrease in performance of the coil unit 5 due to the presence of the fourth gap 54 can even more effectively suppressed.

[0144] Each of the gaps 51 to 54 extends into a region surrounded by the turn portion 101 that forms the innermost periphery of the coil element 10i. In the illustrated example, the first gap 51 and the third gap 53 are positioned in the first direction D1. Therefore, the first gap 51 and the third gap 53 extend continuously in the second direction D2. Furthermore, the second gap 52 and the fourth gap 54 are positioned in the second direction D2. Therefore, the second gap 52 and the fourth gap 54 extend continuously in the first direction D1. However, this is not limiting. The positions of the first gap 51 and the third gap 53 in the first direction D1 may be different. Furthermore, the positions of the second gap 52 and the fourth gap 54 in the second direction D2 may be different.

[0145] When viewed in the axial direction, the first gap 51 and the third gap 53 are formed so that their extensions pass through the central axis C. In other words, the first gap 51 and the third gap 53 are formed at positions farthest from the second straight portion 12 and the fourth straight portion 14 of the turn portion 101 that form the innermost periphery of the coil element 10i. This effectively prevents magnetic field lines formed around the second straight portion 12 and the fourth straight portion 14 from reaching the second shield member 40 through the first gap 51 and the third gap 53. This effectively prevents an increase in loss (heat generation) of the coil unit 5 due to the presence of the first gap 51 and the third gap 53, and effectively prevents a decrease in performance of the coil unit 5 due to the presence of the first gap 51 and the third gap 53.

[0146] Further, when viewed in the axial direction, the second gap 52 and the fourth gap 54 are formed so that their extensions pass through the central axis C. In other words, the second gap 52 and the fourth gap 54 are formed at positions farthest from the first straight portion 11 and the third straight portion 13 of the turn portion 101 that form the innermost periphery of the coil element 10i. This effectively prevents magnetic field lines formed around the first straight portion 11 and the third straight portion 13 from reaching the second shield member 40 through the second gap 52 and the fourth gap 54. This effectively prevents an increase in loss (heat generation) of the coil unit 5 due to the presence of the second gap 52 and the fourth gap 54, and effectively prevents a decrease in performance of the coil unit 5 due to the presence of the second gap 52 and the fourth gap 54.

[0147] (Second shielding member) The second shielding member 40 is disposed on the second side of the coil 10. The second shielding member 40 shields the electromagnetic waves emitted by the coil 10 from the second side. The electromagnetic waves emitted by the coil unit 5 are blocked by the second shielding member 40, thereby preventing the electromagnetic waves from affecting other electronic components, the human body, etc. The second shielding member 40 can be formed from a metal such as aluminum. When the coil unit 5 is attached to an automobile, the second shielding member 40 may be a metal plate that forms the body of the automobile.

[0148] As shown in FIG. 4 , the second shield member 40 is disposed at a distance from the first shield member 30. A spacer 45 may be disposed between the second shield member 40 and the first shield member 30. This allows the distance between the second shield member 40 and the first shield member 30 to be maintained at a predetermined distance. The spacer 45 is not particularly limited as long as it is an insulating material, but is preferably a thermally conductive material. This allows the spacer 45 to promote heat dissipation from the coil unit 5. The first shield member 30 and the second shield member 40 may be joined via the thermally conductive spacer 45.

[0149] The thermally conductive member serving as the spacer 45 can be formed, for example, from an insulating heat dissipation material prepared by dispersing a highly thermally conductive material in an insulating resin. Furthermore, if high thermal conductivity is required for the spacer 45, the spacer 45 may be prepared using the insulating heat dissipation material and a metal member. For example, a spacer 45 having high thermal conductivity can be prepared by sandwiching a metal block made of a metal such as aluminum between films made of the insulating heat dissipation material. The spacer 45 prepared in this manner is disposed between the first shielding member 30 and the second shielding member 40 so that the films are positioned between the first shielding member 30 and the metal block and between the second shielding member 40 and the metal block. This effectively promotes heat dissipation from the coil unit 5 while ensuring insulation between the first shielding member 30 and the second shielding member 40.

[0150] Here, when the second shield member 40 is disposed close to the first shield member 30, for example, when the distance between the second shield member 40 and the first shield member 30 is set to 10 mm or less, it is believed that magnetic field lines generated in the coil 10 are more likely to reach the second shield member 40, which in turn makes it easier for eddy currents to be generated in the second shield member 40. When eddy currents are more likely to be generated in the second shield member 40, loss in the second shield member 40 increases, resulting in increased loss in the coil unit 5. In particular, in the coil unit 5 of this embodiment, gaps 51-54 are formed in the first shield member 30. Therefore, it is believed that the magnetic field lines reach the second shield member 40 through the gaps 51-54 in the first shield member 30. Therefore, when the second shield member 40 is disposed close to the first shield member 30 in the coil unit 5 of this embodiment, it is believed that loss in the coil unit 5 is greater than in a coil unit in which the gaps 50 are not formed in the first shield member 30.

[0151] However, according to the findings of the present inventors, by including a magnetic resin layer 20 in direct contact (or in close contact) with the second main surface 10b of the coil 10 in the coil unit 5, it is possible to suppress an increase in loss in the coil unit 5 caused by bringing the second shield member 40 closer to the first shield member 30. Furthermore, according to the findings of the present inventors, by setting the positional relationship between the coil 10 and the gaps 51-54 between the shield pieces 31-34 as described above, it is possible to suppress an increase in loss in the coil unit 5 caused by bringing the second shield member 40 closer to the first shield member 30. This contributes to reducing the dimensions of the coil unit 5 (particularly the dimensions along the axial direction).

[0152] When the coil unit 5 is mounted on an automobile, the installation space is limited. For this reason, it is advantageous to reduce the dimensions of the coil unit 5. Therefore, in the present embodiment, when the coil unit 5 is a power receiving coil unit installed in an automobile, the distance L1 between the second shield member 40 and the first shield member 30 may be 10 mm or less, 5 mm or less, 3 mm or less, 2 mm or less, or 1 mm or less. On the other hand, when the coil unit 5 is a power transmitting coil unit installed on a road or in a parking lot, the distance L1 between the second shield member 40 and the first shield member 30 may be 10 mm or more, 15 mm or more, or 20 mm or more. However, the longer the distance L1 between the second shield member 40 and the first shield member 30, the more difficult it is for heat to be dissipated from the coil unit 5, which may cause the coil unit 5 to become hot. For this reason, even when the coil unit 5 is installed on a road or a parking lot, the distance L1 between the second shield member 40 and the first shield member 30 is preferably 10 mm or less, more preferably 5 mm or less, even more preferably 3 mm or less, even more preferably 2 mm or less, and even more preferably 1 mm or less. Furthermore, when the distance L1 between the second shield member 40 and the first shield member 30 is 1 mm or more, it is preferable to use a spacer having high thermal conductivity as described above as the spacer 45.

[0153] By arranging the second shielding member 40 and the first shielding member 30 close to each other, the distance L2 between the first main surface 10a of the coil 10 in this embodiment and the first side surface of the second shielding member 40 can be made 10 mm or less, 5 mm or less, or 3 mm or less.

[0154] (Connection terminal) The first connection terminal 46 and the second connection terminal 47 can be used, for example, when connecting to the high-frequency current supply unit 1A or the conversion unit 2A. The first connection terminal 46 and the first turn portion 101 and the second connection terminal 47 and the eighth turn portion 108 are connected by ultrasonic bonding. However, the connection method is not limited thereto, and for example, a conductive adhesive may be used for connection.

[0155] When the coil unit 5 is used as the power transmission coil unit, the first connection terminal 46 and the second connection terminal 47 are connected to the high-frequency current supply unit 1A or AC power supply as shown in Fig. 1. When a high-frequency current is supplied to the coil unit 5, the current can flow from the first connection terminal 46 to the coil 10, and then from the second connection terminal 47 to the high-frequency current supply unit 1A or AC power supply. Also, the current can flow from the second connection terminal 47 to the coil 10, and then from the first connection terminal 46 to the high-frequency current supply unit 1A or AC power supply. This makes it possible to generate a magnetic field including magnetic field lines along the central axis of the coil 10.

[0156] On the other hand, when the coil unit 5 is used as the power receiving coil unit, a high frequency current can be generated in the coil 10 by receiving a magnetic field including magnetic lines of force along the central axis of the coil 10. Then, this high frequency current can be supplied to an external device from the first connection terminal 46 or the second connection terminal 47.

[0157] In the illustrated example, the first connection terminal 46 is connected to the inner end 10e1 of the coil 10. In other words, the first connection terminal 46 is connected to the first straight portion 11 of the first turn portion 101 that forms the innermost periphery of the coil element 10i. The second connection terminal 47 is connected to the outer end 10e2 of the coil 10. In other words, the second connection terminal 47 is connected to the fourth straight portion 14 of the eighth turn portion 108 that forms the outermost periphery of the coil element 10i.

[0158] As shown in FIG. 2 , the first connection terminal 46 extends from the inner side to the outer side in the radial direction of the coil 10. When viewed in the axial direction, the first connection terminal 46 crosses one of the straight portion groups 11G to 14G of the coil element 10i and extends radially outward of the coil 10. To ensure insulation between the first connection terminal 46 and the coil 10 and the first shielding member 30, an insulating material may be disposed between the first connection terminal 46 and the coil 10 and the first shielding member 30. More specifically, the first connection terminal 46 may be coated with an insulating material. Similarly, an insulating material may be disposed between the second connection terminal 47 and the coil 10 and the first shielding member 30. More specifically, the second connection terminal 47 may be coated with an insulating material. For example, a fluororesin may be used as the insulating material for coating the first connection terminal 46 and / or the second connection terminal 47. This ensures insulation between the first connection terminal 46 and / or the second connection terminal 47 and the coil 10 and the first shielding member 30, while effectively promoting heat dissipation from the first connection terminal 46 and / or the second connection terminal 47.

[0159] As shown in FIG. 6A, when the first connection terminal 46 is connected to the inner end 10e1 of the coil 10, the first connection terminal 46 may extend so as to overlap with a gap 50 extending from the inside to the outside of the coil 10 as viewed in the axial direction. In this case, as shown in FIG. 7, the first connection terminal 46 may extend from the inside to the outside of the coil 10 at a height position where it overlaps with the shield piece 30P in a side view of the coil unit 5. In this case, loss (heat generation) of the first shield member 30 can be suppressed. As can be seen from FIG. 7, the connection terminals 46, 47 may be connected to the coil 10 via a conductive connection portion 48.

[0160] When the first connection terminal 46 extends within the gap 50 extending from the inside to the outside of the coil 10, the angle formed by the first connection terminal 46 and the straight portion 11 across which the first connection terminal 46 crosses when viewed in the axial direction may be, for example, 80° to 100°. Furthermore, as shown in Fig. 6A, the first connection terminal 46 may be perpendicular to the straight portion 11. In this case, the magnetic field lines formed around the straight portion 11 are prevented from reaching the second shield member 40 through the gap 50 through which the first connection terminal 46 passes.

[0161] When the second shielding member 40 has a rectangular shape, it is preferable that the first connection terminal 46 and the second connection terminal 47 extend from the same side of the second shielding member 40 when viewed in the axial direction (see FIG. 2). In this case, it is easy to route the wires connected to the first connection terminal 46 and the second connection terminal 47.

[0162] Furthermore, regardless of the shape of the second shield member 40, routing of the wiring connected to the first connection terminal 46 and the second connection terminal 47 is easy as long as the first connection terminal 46 and the second connection terminal 47 have the following positional relationship. That is, as shown in FIG. 6B , a point where the first connection terminal 46 overlaps with the outer periphery of the first shield member 30 as viewed in the axial direction is defined as a first point IP1. Also, a point where the second connection terminal 47 overlaps with the outer periphery of the first shield member 30 as viewed in the axial direction is defined as a second point IP2. Then, as viewed in the axial direction, an angle θ formed by a first imaginary line IL1 connecting the first point IP1 and the central axis C and a second imaginary line IL2 connecting the second point IP2 and the central axis C is 90° or less, preferably 60° or less, more preferably 45° or less, and even more preferably 30° or less.

[0163] Furthermore, the distance between the first point IP1 and the second point IP2 is preferably 100 mm or less, and more preferably 50 mm or less, regardless of the shape of the second shield member 40. By bringing the first point IP1 and the second point IP2 closer to each other in this manner, it becomes easier to route the wires connected to the first connection terminal 46 and the second connection terminal 47.

[0164] 2 to 5B, the ends 10e1 and 10e2 of the coil element 10i have the following positional relationship. That is, if the direction in which the coil element 10i winds around the central axis C from its outer end 10e2 toward its inner end 10e1 is defined as a first winding direction CD, the outer end 10e2 is shifted from the inner end 10e1 in the first winding direction CD. This allows the first point IP1 and the second point IP2 to be close to each other without intersecting the outer end region of the coil element 10i (in the example shown in FIG. 5B, the fourth straight portion 14 of the eighth turn portion) and the first connection terminal 46, as viewed in the axial direction. Since the outer end region of the coil element 10i and the first connection terminal 46 do not intersect, loss (heat generation) of the coil unit 5 can be reduced.

[0165] In the above-described embodiment and some of the modified examples described below, the first straight portion 11 and the fourth straight portion 14 form the ends of the coil element 10i, but this is not limited to this. Any straight portion among the first to fourth straight portions 11 to 14 may form the end of the coil element 10i.

[0166] <<Modifications>> It should be noted that various modifications can be made to the above-described first embodiment. Modifications of the first embodiment will be described below with reference to Figs.

[0167] First, modified examples of the positional relationship between the coil 10 and the gap 50 will be described with reference to Figures 8 to 16. In Figures 8 to 16, the first connection terminal 46 and the second connection terminal 47 are not shown.

[0168] For example, in the coil unit 5 shown in FIG. 8, the first shield member 30 includes two shield pieces 31-32. Each of the shield pieces 31-32 has a rectangular shape. A gap 50 formed between adjacent shield pieces 31, 32 crosses a part of the first straight portion group 11G and the third straight portion group 13G when viewed in the axial direction. The gap 50 is formed at a position overlapping with the central axis C when viewed in the axial direction. This coil unit 5 can also suppress an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50, and can suppress a decrease in performance of the coil unit 5 due to the presence of the gap 50. Note that in the example shown in FIG. 8, the gap 50 is perpendicular to the first straight portion group 11G and the third straight portion group 13G when viewed in the axial direction.

[0169] In the example shown in FIG. 9 , the first shield member 30 includes six shield pieces 31 to 36. Each of the shield pieces 31 to 36 has a rectangular shape. Two of the seven gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 extend between the first straight portion group 11G and the central axis C when viewed in the axial direction. Two of the seven gaps 50 extend between the third straight portion group 13G and the central axis C when viewed in the axial direction. The gaps 50 extend inward of the first turn portion 101 that forms the innermost periphery of the coil element 10i, thereby suppressing an increase in loss (heat generation) of the coil unit 5 due to the presence of the gaps 50 and suppressing a deterioration in performance of the coil unit 5 due to the presence of the gaps 50. In the example shown in FIG. 9, six of the seven gaps 50 are orthogonal to any of the first to fourth linear portion groups 11G to 14G when viewed in the axial direction.

[0170] 10 and 11, the first shield member 30 includes four shield pieces 31 to 34. Each of the shield pieces 31 to 34 has a rectangular shape. One of three gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34 crosses the first straight line portion group 11G when viewed in the axial direction. This gap 50 is perpendicular to the first straight line portion group 11G when viewed in the axial direction. One of the other two gaps 50 extends along the second straight line portion 12 within the second straight line portion group 12G when viewed in the axial direction. The other of the other two gaps 50 extends along the fourth straight line portion 14 within the fourth straight line portion group 14. In this way, some of the gaps 50 formed in the first shield member 30 may extend, as viewed in the axial direction, within any of the straight line portion groups 11G-14G that form the coil 10, along the straight line portions 11-14 that make up that straight line portion group 11G-14G. In this case, too, it is possible to at least suppress an increase in loss (heat generation) of the coil unit 5 due to the presence of the gaps 50 that cross the first straight line portion group 11G, and it is also possible to suppress a decrease in performance of the coil unit 5 due to the presence of the gaps 50.

[0171] According to the findings of the inventors, when a gap 50 extends within any of the straight line portion groups 11G to 14G along the straight line portions 11 to 14 constituting that straight line portion group 11G to 14G as viewed in the axial direction, the increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50 becomes greater the closer the gap 50 is to the radial center of the straight line portion group 11G to 14G. Therefore, as shown in Fig. 10, it is preferable that the gap 50 extending within the second straight line portion group 12G extend closer to the central axis C (inward in the radial direction) than the smallest integer-th second straight line portion 12, counting from the innermost second straight line portion 12 (the second straight line portion 12 of the first turn portion 101) among the plurality of second straight line portions 12 in the second straight line portion group 12G, that is equal to or greater than the value obtained by dividing the total number of the plurality of second straight line portions 12 by 3. Alternatively, as shown in FIG. 11 , the gaps 50 extending within the second straight portion group 12G preferably extend on the side opposite the central axis C (radially outward) from the smallest integer-th second straight portion 12 that is equal to or greater than the value obtained by dividing the total number of the second straight portions 12, counting from the outermost second straight portion 12 (the second straight portion 12 of the eighth turn portion 108) among the plurality of second straight portions 12 in the second straight portion group 12G, by 3. Specifically, in the example shown in FIGS. 10 and 11 , the total number of second straight portions 12 in the second straight portion group 12G is eight. The smallest integer that is equal to or greater than the value obtained by dividing 8 by 3 is 3. Therefore, as shown in FIG. 10 , the gaps 50 extending within the second straight portion group 12G are preferably located radially inward from the second straight portion 12 of the third turn portion 103. Alternatively, the gaps 50 extending within the second straight portion group 12G are preferably positioned radially outward of the second straight portion 12 of the sixth turn portion 106, as shown in FIG.

[0172] 10, the gaps 50 extending within the fourth straight portion group 14G preferably extend closer to the central axis C (radially inward) than the smallest integer-numbered fourth straight portion 14 that is equal to or greater than the value obtained by dividing the total number of the plurality of fourth straight portions 14 by 3, counting from the innermost fourth straight portion 14 (the fourth straight portion 14 of the first turn portion 101) among the plurality of fourth straight portions 14 in the fourth straight portion group 14G. Alternatively, as shown in FIG. 11, the gaps 50 extending within the fourth straight portion group 14G preferably extend closer to the central axis C (radially outward) than the smallest integer-numbered fourth straight portion 14 that is equal to or greater than the value obtained by dividing the total number of the plurality of fourth straight portions 14 by 3, counting from the outermost fourth straight portion 14 (the fourth straight portion 14 of the eighth turn portion 108) among the plurality of fourth straight portions 14 in the fourth straight portion group 14G. 10 and 11, the total number of fourth straight portions 14 in the fourth straight portion group 14G is eight. The smallest integer equal to or greater than 8 divided by 3 is 3. Therefore, the gaps 50 extending within the fourth straight portion group 14G are preferably located radially inward of the fourth straight portion 14 of the third turn portion 103, as shown in FIG. 10. Alternatively, the gaps 50 extending within the fourth straight portion group 14G are preferably located radially outward of the fourth straight portion 14 of the sixth turn portion 106, as shown in FIG. 11.

[0173] This also applies to the case where the first shield member 30 has gaps 50 extending along the first straight portion 11 in the first straight portion group 11G, as viewed in the axial direction, or the case where the first shield member 30 has gaps 50 extending along the third straight portion 13 in the third straight portion group 13G, as viewed in the axial direction. In the example shown in FIGS. 12 to 16, the first shield member 30 includes six shield pieces 31 to 36. Each of the shield pieces 31 to 36 has a rectangular shape. Three of the seven gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 cross a portion of the first straight portion group 11G and / or a portion of the third straight portion group 13G, as viewed in the axial direction. These three gaps 50 are orthogonal to a part of the first straight line portion group 11G and / or a part of the third straight line portion group 13G when viewed in the axial direction. One of the other gaps 50 extends along the first straight line portion 11 within the first straight line portion group 11G when viewed in the axial direction. The other two of the other gaps extend along the third straight line portion 13 within the third straight line portion group 13G.

[0174] 12 and 13, the gaps 50 extending within the first straight portion group 11G preferably extend closer to the central axis C (radially inward) than the smallest integer-numbered first straight portion 11, counting from the innermost first straight portion 11 (the first straight portion 11 of the first turn portion 101) among the plurality of first straight portions 11 in the first straight portion group 11G, that is equal to or greater than the value obtained by dividing the total number of the plurality of first straight portions 11 by 3. Alternatively, as shown in FIGS. 15 and 16, the gaps 50 extending within the first straight portion group 11G preferably extend closer to the side opposite the central axis C (radially outward) than the smallest integer-numbered first straight portion 11, counting from the outermost first straight portion 11 (the first straight portion 11 of the eighth turn portion 108) among the plurality of first straight portions 11 in the first straight portion group 11G, that is equal to or greater than the value obtained by dividing the total number of the plurality of first straight portions 11 by 3. 12 to 16, the total number of first straight portions 11 in the first straight portion group 11G is eight. The smallest integer equal to or greater than 8 divided by 3 is 3. Therefore, the gaps 50 extending within the first straight portion group 11G are preferably located radially inward of the first straight portion 11 of the third turn portion 103, as shown in FIGS. 12 and 13. Alternatively, the gaps 50 extending within the first straight portion group 11G are preferably located radially outward of the first straight portion 11 of the sixth turn portion 106, as shown in FIGS. 15 and 16.

[0175] 12 and 13, the gaps 50 extending within the third straight portion group 13G preferably extend closer to the central axis C (radially inward) than the smallest integer-numbered third straight portion 13, counting from the innermost third straight portion 13 (the third straight portion 13 of the first turn portion 101) among the plurality of third straight portions 13 in the third straight portion group 13G, that is equal to or greater than the value obtained by dividing the total number of the plurality of third straight portions 13 by 3. Alternatively, as shown in FIGS. 15 and 16, the gaps 50 extending within the third straight portion group 13G preferably extend closer to the side opposite the central axis C (radially outward) than the smallest integer-numbered third straight portion 13, counting from the outermost third straight portion 13 (the third straight portion 13 of the eighth turn portion 108) among the plurality of third straight portions 13 in the third straight portion group 13G, that is equal to or greater than the value obtained by dividing the total number of the plurality of third straight portions 13 by 3. 12 to 16, the total number of third straight portions 13 in the third straight portion group 13G is eight. The smallest integer equal to or greater than the value obtained by dividing eight by three is three. Therefore, the gaps 50 extending within the third straight portion group 13G are preferably located radially inward of the third straight portion 13 of the third turn portion 103, as shown in FIGS. 12 and 13. Alternatively, the gaps 50 extending within the third straight portion group 13G are preferably located radially outward of the third straight portion 13 of the sixth turn portion 106, as shown in FIGS. 15 and 16.

[0176] 17 to 19, the coil 10 may include a plurality of spiral-shaped coil elements 10j, 10jj. In the example shown in Fig. 17 to 19, the coil 10 includes two coil elements, a first coil element 10j and a second coil element 10jj, arranged in the axial direction. The pitch P of the first coil element 10j and the second coil element 10jj along the axial direction is, for example, 5 mm or more and 40 mm or less.

[0177] In the illustrated example, each coil element 10j, 10jj includes a conductor 10E having a spiral shape. The conductor 10E includes a plurality of turn portions 101 to 105 arranged in the radial direction. In the illustrated example, the conductor 10E includes first to fifth turn portions 101 to 105. The first to fifth turn portions 101 to 105 are arranged in this order from the inside to the outside in the radial direction. In other words, the first turn portion 101 is located at the innermost position in the radial direction, and the fifth turn portion 105 is located at the outermost position in the radial direction. In further words, the first turn portion 101 forms the innermost portion of each coil element 10j, 10jj. Furthermore, the fifth turn portion 105 forms the outermost portion of each coil element 10j, 10jj.

[0178] The turn portions 101-105 of each coil element 10j, 10jj extend on an imaginary plane perpendicular to the axial direction. The first to fifth turn portions 101-105 are connected in this order, so that the coil elements 10j, 10jj form a spiral shape around the central axis C. In the illustrated example, each coil element 10j, 10jj (electrical conductor 10E) is wound so that the turn portions 101-105 form a substantially rectangular shape, but this is not limited thereto. The turn portions 101-105 may also be wound so as to form a substantially polygonal shape other than a rectangular shape. As can be seen from FIGS. 17 and 18, the first to fifth turn portions 101-105 of the first coil element 10j are aligned in the axial direction with the first to fifth turn portions 101-105 of the second coil element 10jj, respectively.

[0179] Each turn portion 101-105 of each coil element 10j, 10jj includes a plurality of straight portions 11-13 arranged around the central axis C. The straight portions 11-13 adjacent to each other in the circumferential direction of a circle centered on the central axis C are connected to each other. In the illustrated example, the first to fifth turn portions 101-105 include a first straight portion 11 and a third straight portion 13 extending in a first direction D1, and a second straight portion 12 extending in a second direction D2. Furthermore, the first to fourth turn portions 101-104 of each coil element 10j, 10jj include a turn connection portion 16. The first to fourth turn portions 101-104 are connected to the second to fifth turn portions 102-105 at the turn connection portion 16, respectively.

[0180] The first direction D1 and the second direction D2 are not parallel to each other. In the illustrated example, the first direction D1 and the second direction D2 are perpendicular to each other. In each of the turn sections 101 to 105, the first straight section 11 and the third straight section 13 are arranged so that the central axis C passes therebetween. In each of the turn sections 101 to 105, the second straight section 12 and the turn connecting section 16 are arranged so that the central axis C passes therebetween.

[0181] In each of the turn portions 101 to 105 of the first coil element 10j, adjacent ends of the first straight portion 11 and the second straight portion 12 are connected via a first-A intermediate curved portion 151 that curves along the circumferential direction. Similarly, in each of the turn portions 101 to 105 of the first coil element 10j, adjacent ends of the second straight portion 12 and the third straight portion 13 are connected via a first-B intermediate curved portion 152 that curves along the circumferential direction. In each of the first to fourth turn portions 101 to 104 of the first coil element 10j, adjacent ends of the first straight portion 11 and the turn connection portion 16 are connected via a first-D intermediate curved portion 154 that curves along the circumferential direction. Furthermore, the turn connection portions 16 of the first to fourth turn portions 101 to 104 of the first coil element 10j are each connected to the third straight portions 13 of the second to fifth turn portions 102 to 105 of the first coil element 10j via a first C intermediate curve portion 153 that curves along the circumferential direction.

[0182] In each of the turn portions 101-105 of the second coil element 10jj, adjacent ends of the first straight portion 11 and the second straight portion 12 are connected via a first-A intermediate curve portion 151. Similarly, in each of the turn portions 101-105 of the second coil element 10jj, adjacent ends of the second straight portion 12 and the third straight portion 13 are connected via a first-B intermediate curve portion 152. In each of the first to fourth turn portions 101-104 of the second coil element 10jj, adjacent ends of the third straight portion 13 and the turn connection portion 16 are connected via a first-C intermediate curve portion 153. Furthermore, the turn connection portions 16 of the first to fourth turn portions 101-104 of the second coil element 10jj are connected to the first straight portions 11 of the second to fifth turn portions 102-105 of the second coil element 10jj via first-D intermediate curve portions 154, respectively.

[0183] 17, the first to third straight portions 11 to 13 and the turn connection portion 16 of the first turn portion 101 of the first coil element 10j are respectively aligned in the axial direction with the first to third straight portions 11 to 13 and the turn connection portion 16 of the first turn portion 101 of the second coil element 10jj. Furthermore, the first to third straight portions 11 to 13 and the turn connection portion 16 of the second turn portion 102 of the first coil element 10j are respectively aligned in the axial direction with the first to third straight portions 11 to 13 and the turn connection portion 16 of the second turn portion 102 of the second coil element 10jj. Furthermore, the first to third straight portions 11 to 13 and the turn connection portion 16 of the third turn portion 103 of the first coil element 10j are respectively aligned in the axial direction with the first to third straight portions 11 to 13 and the turn connection portion 16 of the third turn portion 103 of the second coil element 10jj. Furthermore, the first to third straight portions 11 to 13 and the turn connection portion 16 of the fourth turn portion 104 of the first coil element 10j are aligned in the axial direction with the first to third straight portions 11 to 13 and the turn connection portion 16 of the fourth turn portion 104 of the second coil element 10jj, respectively. Furthermore, the first to third straight portions 11 to 13 of the fifth turn portion 105 of the first coil element 10j are aligned in the axial direction with the first to third straight portions 11 to 13 of the fifth turn portion 105 of the second coil element 10jj, respectively.

[0184] 17, the third straight portion 13 of the first turn portion 101 located in the innermost position of the first coil element 10j is electrically connected to the first straight portion 11 of the first turn portion 101 located in the innermost position of the second coil element 10jj. A first connection terminal 46 is connected to the first straight portion 11 of the fifth turn portion 105 located in the outermost position of the first coil element 10j. A second connection terminal 47 is connected to the third straight portion 13 of the fifth turn portion 105 located in the outermost position of the second coil element 10jj.

[0185] As shown in FIG. 18, the first coil element 10j forms the first main surface 10a of the coil 10. The second coil element 10jj forms the second main surface 10b of the coil 10. The magnetic substance resin layer 20 is in direct contact with the second main surface 10b of the coil 10. In other words, the magnetic substance resin layer 20 is in direct contact with the conductor 10E of the second coil element 10jj. In the example shown in FIG. 18, the coil 10 is embedded in the magnetic substance resin layer 20. In the example shown in FIG. 18, the magnetic substance resin layer 20 is also in direct contact with or in close contact with the surface of the first coil element 10j facing the second side. However, the present invention is not limited to this, and the magnetic resin layer 20 does not have to be in direct contact with or in close contact with the surface of the first coil element 10j facing the second side.

[0186] 17 to 19, the first shield member 30 includes nine shield pieces 31 to 39. Each of the shield pieces 31 to 39 has a rectangular shape. Two of the twelve gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31; 32, 39; 34, 39; 36, 39; 38, 39 cross the first straight line portion group 11G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction. These two gaps 50 are perpendicular to the first straight line portion group 11G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction. Furthermore, two of the twelve gaps 50 cross the second straight portion group 12G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction. These two gaps 50 are perpendicular to the second straight portion group 12G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction. Furthermore, two of the twelve gaps 50 cross the third straight portion group 13G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction. These two gaps 50 are perpendicular to the third straight portion group 13G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction. Furthermore, four of the twelve gaps 50 are located radially inward of the first turn portion 101, which is located at the innermost position of the coil elements 10j and 10jj when viewed in the axial direction.

[0187] In the example described above, the first shield member 30 includes the gap 50 that crosses any of the straight line portion groups 11G to 14G of the coil elements 10i; 10j, and 10jj, but is not limited to this. The first shield member 30 does not have to include the gap 50 that crosses the straight line portion groups 11G to 14G. In the example shown in Fig. 20, the first shield member 30 does not include the gap 50 that crosses the first to fourth straight line portion groups 11G to 14G of the coil elements 10j and 10jj.

[0188] In the example shown in FIG. 20 , the first shield member 30 includes nine shield pieces 31 to 39. Each of the shield pieces 31 to 39 has a rectangular shape. Two of the twelve gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31; 32, 39; 34, 39; 36, 39; 38, 39 cross the first A intermediate curved portion group 151G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction. Furthermore, two of the twelve gaps 50 cross the first B intermediate curved portion group 152G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction. Moreover, two of the twelve gaps 50 cross the first C intermediate curved portion group 153G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction. Moreover, two of the twelve gaps 50 cross the first D intermediate curved portion group 154G of the first coil element 10j and the second coil element 10jj when viewed in the axial direction.

[0189] Of course, as shown in Figures 21 to 25, the first shield member 30 may include both gaps 50 that cross the first to fourth straight line portion groups 11G to 14G of the coil elements 10i, 10j, and gaps 50 that cross the 1A to 1D intermediate curve portion groups 151G to 154G.

[0190] In the example shown in FIGS. 22 and 23, the first shield member 30 includes eight shield pieces 31-38. Each of the shield pieces 31-38 has a triangular shape. More specifically, each of the shield pieces 31-38 has a right-angled triangular shape. First to eighth gaps 51-58 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31 extend radially from the central axis C. When viewed in the axial direction, the gaps 51, 53, 55, and 57 each cross at least a portion of the 1A-1D intermediate curved portion groups 151G-154G. In the illustrated example, when viewed in the axial direction, the gaps 51, 53, 55, and 57 each cross the 1A-1D intermediate curved portion groups 151G-154G. In other words, when viewed in the axial direction, the gaps 51, 53, 55, and 57 extend radially inward from the 1A to 1D intermediate curved portion groups 151G to 154G, respectively, radially outward.

[0191] By arranging the shield pieces 31, 32 so that the first gaps 51 cross the 1A intermediate curved portions 151, the magnetic field lines formed around each 1A intermediate curved portion 151 are prevented from reaching the second shield member 40 through the second gaps 52. This prevents the magnetic field lines formed around the 1A intermediate curved portions 151 from generating eddy currents in the second shield member 40. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the first gaps 51 can be prevented, and that a decrease in performance of the coil unit 5 due to the presence of the first gaps 51 can be prevented.

[0192] When viewed in the axial direction, the angle formed by the first gap 51 and the tangent line TL1 of the 1A intermediate curved portion group 151G may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the first gap 51 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the first gap 51 can be effectively suppressed. Furthermore, as can be seen from FIGS. 22 and 23 , when viewed in the axial direction, the first gap 51 may be perpendicular to the tangent line TL1 of the 1A intermediate curved portion group 151G. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the first gap 51 can be more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the first gap 51 can be more effectively suppressed.

[0193] Furthermore, by arranging the shield pieces 33, 34 so that the third gaps 53 cross the 1B intermediate curved portions 152, the magnetic field lines formed around each 1B intermediate curved portion 152 are prevented from reaching the second shield member 40 through the third gaps 53. This prevents the magnetic field lines formed around the 1B intermediate curved portions 152 from generating eddy currents in the second shield member 40. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the third gaps 53 can be prevented, and that a decrease in performance of the coil unit 5 due to the presence of the third gaps 53 can be prevented.

[0194] When viewed in the axial direction, the angle formed by the third gap 53 and the tangent TL2 of the 1B intermediate curved portion group 152G may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the third gap 53 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the third gap 53 can be effectively suppressed. Furthermore, as can be seen from FIGS. 22 and 23 , when viewed in the axial direction, the third gap 53 may be perpendicular to the tangent TL2 of the 1B intermediate curved portion group 152G. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the third gap 53 can be more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the third gap 53 can be more effectively suppressed.

[0195] Furthermore, by arranging the shield pieces 35, 36 so that the fifth gap 55 crosses the 1C intermediate curved portions 153, the magnetic field lines formed around each 1C intermediate curved portion 153 are prevented from reaching the second shield member 40 through the fifth gap 55. This makes it possible to prevent eddy currents from being generated in the second shield member 40 by the magnetic field lines formed around the 1C intermediate curved portions 153. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the fifth gap 55 can be prevented, and that a decrease in performance of the coil unit 5 due to the presence of the fifth gap 55 can be prevented.

[0196] When viewed in the axial direction, the angle formed by the fifth gap 55 and the tangent TL3 of the 1C intermediate curve portion group 153G may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the fifth gap 55 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the fifth gap 55 can be effectively suppressed. Furthermore, as can be seen from FIGS. 22 and 23 , when viewed in the axial direction, the fifth gap 55 may be perpendicular to the tangent TL3 of the 1C intermediate curve portion group 153G. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the fifth gap 55 can be more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the fifth gap 55 can be more effectively suppressed.

[0197] Furthermore, by arranging the shield pieces 37, 38 so that the seventh gap 57 crosses the 1D intermediate curved portion 154, the magnetic field lines formed around each 1D intermediate curved portion 154 are prevented from reaching the second shield member 40 through the seventh gap 57. This prevents the magnetic field lines formed around the 1D intermediate curved portion 154 from generating eddy currents in the second shield member 40. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the seventh gap 57 can be prevented, and that a decrease in performance of the coil unit 5 due to the presence of the seventh gap 57 can be prevented.

[0198] When viewed in the axial direction, the angle formed by the seventh gap 57 and the tangent line TL4 of the 1D intermediate curved portion group 154G may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the seventh gap 57 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the seventh gap 57 can be effectively suppressed. Furthermore, as can be seen from FIGS. 22 and 23 , when viewed in the axial direction, the seventh gap 57 may be perpendicular to the tangent line TL4 of the 1D intermediate curved portion group 154G. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the seventh gap 57 can be more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the seventh gap 57 can be more effectively suppressed.

[0199] In this specification, the tangents to a group of curved lines refer to the tangents to the curved lines that make up the group of curved lines when viewed in the axial direction. Therefore, the tangents TL1 to TL4 to the 1A to 1D intermediate curved line groups 151G to 154G are tangents to the 1A to 1D intermediate curved lines 151 to 154, respectively.

[0200] 22 and 23, the gaps 52, 54, 58 each traverse at least a portion of the first to third straight portion groups 11G to 13G when viewed in the axial direction. In the illustrated example, the gaps 52, 54, 58 each traverse the first to third straight portion groups 11G to 13G. In other words, when viewed in the axial direction, the gaps 52, 54, 58 each extend from radially inward to radially outward of the first to third straight portion groups 11G to 13G.

[0201] When viewed in the axial direction, the angle formed between the eighth gap 58 and the first linear portion 11 is 80° to 100°. More specifically, the eighth gap 58 is perpendicular to the first linear portion 11. When viewed in the axial direction, the angle formed between the second gap 52 and the second linear portion 12 is 80° to 100°. More specifically, the second gap 52 is perpendicular to the second linear portion 12. When viewed in the axial direction, the angle formed between the fourth gap 54 and the third linear portion 13 is 80° to 100°. More specifically, the fourth gap 54 is perpendicular to the third linear portion 13.

[0202] 22, the sixth gaps 56 cross at least a portion of the fourth straight portion group 14G when viewed in the axial direction. In the illustrated example, the sixth gaps 56 cross the fourth straight portion group 14G. In other words, when viewed in the axial direction, the sixth gaps 56 each extend from a radially inner side to a radially outer side of the fourth straight portion group 14G. When viewed in the axial direction, the angle formed between the sixth gaps 56 and the fourth straight portion 14 is 80° to 100°. More specifically, the sixth gaps 56 are perpendicular to the fourth straight portion 14.

[0203] 24 and 25, the angles formed by the gaps 50 crossing the first intermediate curved portion groups 151G-154G and the tangents TL1-TL4 of the first intermediate curved portion groups 151G-154G are 80° to 100° when viewed in the axial direction. In the examples shown in Fig. 24 and 25, the gaps 50 crossing the first intermediate curved portion groups 151G-154G are perpendicular to the tangents TL1-TL4 of the first intermediate curved portion groups 151G-154G when viewed in the axial direction. In this way, various layouts (or various division modes) can be adopted for the layout of the multiple shield pieces 30P (or the division mode of the first shield member 30) so that the angle formed between the gap 50 crossing the first intermediate curved portion group 151G to 154G and the tangent lines TL1 to TL4 of the first intermediate curved portion group 151G to 154G is 80° to 100°.

[0204] Next, modified examples shown in Figures 26 to 29 will be described. In the above-described example, the straight line portion groups 11G, 12G; 12G, 13G; 13G, 14G; 14G, 11G adjacent in the circumferential direction are connected via first intermediate curved line portion groups 151G to 154G, but this is not limited to this. In the example shown in Figures 26 to 29, the straight line portion groups 11G, 12G; 12G, 13G; 13G, 14G; 14G, 11G adjacent in the circumferential direction are connected via first intermediate straight line portion groups 161G to 164G.

[0205] 26 to 29, the coil element 10i has an octagonal shape as a whole. The coil element 10i (electrical conductor 10E) is wound so that each of the turn portions 101 to 108 forms a roughly octagonal shape.

[0206] In the example shown in FIGS. 26 to 29, the first to eighth turn portions 101 to 108 include first intermediate straight portions 161 to 164 in addition to the first to fourth straight portions 11 to 14. The 1A intermediate straight portion 161 and the 1C intermediate straight portion 163 extend in a third direction D3. The third direction D3 is non-parallel to any of the first to second directions D1 and D2. The 1B intermediate straight portion 162 and the 1D intermediate straight portion 164 extend in a fourth direction D4. The fourth direction D4 is non-parallel to any of the first to third directions D1 to D3.

[0207] In each of the turn portions 101 to 108, adjacent ends of the first straight portion 11 and the second straight portion 12 are connected via a 1A intermediate straight portion 161. Similarly, in each of the turn portions 101 to 108, adjacent ends of the second straight portion 12 and the third straight portion 13 are connected via a 1B intermediate straight portion 162. Furthermore, in each of the turn portions 101 to 108, adjacent ends of the third straight portion 13 and the fourth straight portion 14 are connected via a 1C intermediate straight portion 163.

[0208] Furthermore, adjacent ends of the fourth straight portions 14 and the first straight portions 11 of the radially adjacent turn portions 101, 102;...; 107, 108 are connected via a 1D intermediate straight portion 164. For example, adjacent ends of the fourth straight portion 14 of the first turn portion 101 and the first straight portion 11 of the second turn portion 102 are connected via the 1D intermediate straight portion 164. Also, adjacent ends of the fourth straight portion 14 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103 are connected via the 1D intermediate straight portion 164.

[0209] The first A intermediate straight portions 161 of the plurality of turn portions 101-108 are arranged in the radial direction to form a first A intermediate straight portion group 161G. The first B intermediate straight portions 162 of the plurality of turn portions 101-108 are arranged in the radial direction to form a first B intermediate straight portion group 162G. The first C intermediate straight portions 163 of the plurality of turn portions 101-108 are arranged in the radial direction to form a first C intermediate straight portion group 163G. The first D intermediate straight portions 164 of the plurality of turn portions 101-108 are arranged in the radial direction to form a first D straight portion group 164G. The radially adjacent first intermediate straight portions 161, 161; 162, 162; 163, 163; 164, 164 are radially spaced apart from each other. The 1A to 1D intermediate straight line portion groups 161G to 164G are groups of parallel straight lines made up of a plurality of 1A to 1D intermediate straight line portions 161 to 164, respectively.

[0210] As described above, the coil element 10i has an octagonal shape as a whole. The coil element 10i (electrical conductor 10E) is wound so that the turn portions 101-108 form a roughly octagonal shape. In other words, the coil element 10i includes eight straight line portion groups 11-14, 161-164 extending along the eight sides of the octagon. In the illustrated example, the angle between the first straight line portion 11 and the 1A intermediate straight line portion 161 is 125° to 145° when viewed in the axial direction. The angle between the 1A intermediate straight line portion 161 and the second straight line portion 12 is 125° to 145° when viewed in the axial direction. The angle between the second straight line portion 12 and the 1B intermediate straight line portion 162 is 125° to 145° when viewed in the axial direction. Furthermore, when viewed in the axial direction, the angle formed between the 1B intermediate straight portion 162 and the third straight portion 13 is 125° to 145°. When viewed in the axial direction, the angle formed between the third straight portion 13 and the 1C intermediate straight portion 163 is 125° to 145°. When viewed in the axial direction, the angle formed between the 1C intermediate straight portion 163 and the fourth straight portion 14 is 125° to 145°. When viewed in the axial direction, the angle formed between the fourth straight portion 14 and the 1D intermediate straight portion 164 is 125° to 145°. When viewed in the axial direction, the angle formed between the 1D intermediate straight portion 164 and the first straight portion 11 is 125° to 145°.

[0211] In particular, in the example shown in FIGS. 26 to 29 , the angle formed between the first straight portion 11 and the 1A intermediate straight portion 161 is 135° when viewed in the axial direction. The angle formed between the 1A intermediate straight portion 161 and the second straight portion 12 is also 135° when viewed in the axial direction. The angle formed between the second straight portion 12 and the 1B intermediate straight portion 162 is also 135° when viewed in the axial direction. The angle formed between the 1B intermediate straight portion 162 and the third straight portion 13 is also 135° when viewed in the axial direction. The angle formed between the third straight portion 13 and the 1C intermediate straight portion 163 is also 135° when viewed in the axial direction. The angle formed between the 1C intermediate straight portion 163 and the fourth straight portion 14 is also 135° when viewed in the axial direction. Furthermore, when viewed in the axial direction, the angle formed between the fourth straight portion 14 and the 1D intermediate straight portion 164 is 135°. Furthermore, when viewed in the axial direction, the angle formed between the 1D intermediate straight portion 164 and the first straight portion 11 is 135°.

[0212] 26 to 29, the coil element 10i has a regular octagonal shape as a whole. The coil element 10i (electrical conductor 10E) is wound so that the turn portions 101 to 108 form a regular octagon. In other words, the coil element 10i includes eight straight line portion groups 11 to 14, 161 to 164 extending along the eight sides of the regular octagon. This can improve the performance of the coil 10.

[0213] The linear portions 11 to 14 and the first intermediate linear portions 161 to 164 that are adjacent to each other in the circumferential direction may be connected by curved portions.

[0214] In the example shown in FIG. 26, the first shielding member 30 includes first to fourth shielding pieces 31 to 34, similar to the examples shown in FIGS. 2 to 5B. Each of the shielding pieces 31 to 34 has a rectangular shape. First to fourth gaps 51 to 54 are formed in the first shielding member 30. The first to fourth gaps 51 to 54 cross at least a portion of the first to fourth straight line portion groups 11G to 14G, respectively, when viewed in the axial direction. In the example shown in FIG. 26, the first to fourth gaps 51 to 54 cross the first to fourth straight line portion groups 11G to 14G, respectively, when viewed in the axial direction.

[0215] 26, the angle formed between the first gap 51 and the first straight portion 11 of the first straight portion group 11G may be, for example, 80° to 100° when viewed in the axial direction. Similarly, the angle formed between the second gap 52 and the second straight portion 12 of the second straight portion group 12G may be, for example, 80° to 100° when viewed in the axial direction. Furthermore, the angle formed between the third gap 53 and the third straight portion 13 of the third straight portion group 13G may be, for example, 80° to 100° when viewed in the axial direction. Furthermore, the angle formed between the fourth gap 54 and the fourth straight portion 14 of the fourth straight portion group 14G may be, for example, 80° to 100° when viewed in the axial direction.

[0216] 26 , the first gap 51 may be perpendicular to the first straight portion 11 of the first straight portion group 11G when viewed in the axial direction. Furthermore, the second gap 52 may be perpendicular to the second straight portion 12 of the second straight portion group 12G when viewed in the axial direction. Furthermore, the third gap 53 may be perpendicular to the third straight portion 13 of the third straight portion group 13G when viewed in the axial direction. Furthermore, the fourth gap 54 may be perpendicular to the fourth straight portion 14 of the fourth straight portion group 14G when viewed in the axial direction.

[0217] In the example shown in FIG. 27, the first shielding member 30 includes 12 shielding pieces 30P. Seventeen gaps 50 are formed in the first shielding member 30. In the example shown in FIG. 27, 14 of the 17 gaps 50 cross at least a portion of the first to fourth straight line portion groups 11G to 14G and / or the 1A to 1D intermediate straight line portion groups 161G to 164G when viewed in the axial direction. Two of the 14 gaps 50 cross the first straight line portion group 11G or the third straight line portion group 13G. In the example shown in FIG. 27, when viewed in the axial direction, the angle formed between the gap 50 crossing the first straight line portion group 11G and the first straight line portion group 11G is 80° to 100°, more specifically, 90°. In the example shown in FIG. 27, the angle formed between the gaps 50 crossing the third straight line group 13G and the third straight line group 13G when viewed in the axial direction is 80° to 100°, and more specifically, 90°.

[0218] 27, one of the 17 gaps 50 extends within and along the second straight portion group 12G. The gap 50 extending within the second straight portion group 12G extends closer to the central axis C (inward in the radial direction) than the smallest integer-th second straight portion 12 that is equal to or greater than the value obtained by dividing the total number of the plurality of second straight portions 12 by 3, counting from the innermost second straight portion 12 (the second straight portion 12 of the first turn portion 101) among the plurality of second straight portions 12 in the second straight portion group 12G.

[0219] 27, one of the 17 gaps 50 extends within the fourth straight portion group 14G along the second straight portion group 14G. The gap 50 extending within the fourth straight portion group 14G extends closer to the central axis C (inward in the radial direction) than the smallest integer-th fourth straight portion 14 that is equal to or greater than the value obtained by dividing the total number of the plurality of fourth straight portions 14 by 3, counting from the innermost fourth straight portion 14 (the fourth straight portion 14 of the first turn portion 101) among the plurality of fourth straight portions 14 in the fourth straight portion group 14G.

[0220] In the example shown in FIG. 27, one of the seventeen gaps 50 does not cross the coil 10 .

[0221] In the example shown in FIG. 28, the first shield member 30 includes eight shield pieces 31 to 38. Each of the shield pieces 31 to 38 has a triangular shape. More specifically, each of the shield pieces 31 to 38 has a right-angled triangle shape. First to eighth gaps 51 to 58 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31 extend radially from the central axis C. When viewed in the axial direction, the gaps 51, 53, 55, and 57 each cross at least a portion of the 1A to 1D intermediate straight portion groups 161G to 164G. In the illustrated example, when viewed in the axial direction, the gaps 51, 53, 55, and 57 each cross the 1A to 1D intermediate straight portion groups 161G to 164G. In other words, when viewed in the axial direction, the gaps 51, 53, 55, 57 extend radially inward from the radially outward of the 1A to 1D intermediate straight portion groups 161G to 164G, respectively.

[0222] By arranging the shield pieces 31, 32 so that the first gaps 51 cross the 1A intermediate straight portions 161, the magnetic field lines formed around each 1A intermediate straight portion 161 are prevented from reaching the second shield member 40 through the first gaps 51. This prevents the magnetic field lines formed around the 1A intermediate straight portions 161 from generating eddy currents in the second shield member 40. This means that it is possible to prevent an increase in loss (heat generation) of the coil unit 5 due to the presence of the second gaps 52, and it is also possible to prevent a decrease in performance of the coil unit 5 due to the presence of the first gaps 51.

[0223] When viewed in the axial direction, the angle formed between the first gap 51 and the 1A intermediate straight portion 161 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the first gap 51 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the first gap 51 can be effectively suppressed. Furthermore, as can be seen from FIG. 28 , when viewed in the axial direction, the first gap 51 may be perpendicular to the 1A intermediate straight portion 161. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the first gap 51 can be even more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the first gap 51 can even more effectively suppressed.

[0224] Furthermore, by arranging the shield pieces 33, 34 so that the third gaps 53 cross the 1B intermediate straight portions 162, the magnetic field lines formed around each 1B intermediate straight portion 162 are prevented from reaching the second shield member 40 through the third gaps 53. This prevents the magnetic field lines formed around the 1B intermediate straight portions 162 from generating eddy currents in the second shield member 40. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the third gaps 53 can be prevented, and that a decrease in performance of the coil unit 5 due to the presence of the third gaps 53 can be prevented.

[0225] As viewed in the axial direction, the angle formed by the third gap 53 and the 1B intermediate straight portion 162 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the third gap 53 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the third gap 53 can be effectively suppressed. Furthermore, as can be seen from FIG. 28 , as viewed in the axial direction, the third gap 53 may be perpendicular to the 1B intermediate straight portion 162. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the third gap 53 can be even more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the third gap 53 can even more effectively suppressed.

[0226] Furthermore, by arranging the shield pieces 35, 36 so that the fifth gap 55 crosses the 1C intermediate straight portion 163, the magnetic field lines formed around each 1C intermediate straight portion 163 are prevented from reaching the second shield member 40 through the fifth gap 55. This makes it possible to prevent eddy currents from being generated in the second shield member 40 by the magnetic field lines formed around the 1C intermediate straight portion 163. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the fifth gap 55 can be prevented, and that a decrease in performance of the coil unit 5 due to the presence of the fifth gap 55 can be prevented.

[0227] When viewed in the axial direction, the angle formed by the fifth gap 55 and the 1C intermediate straight portion 163 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the fifth gap 55 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the fifth gap 55 can be effectively suppressed. Furthermore, as can be seen from FIG. 28 , when viewed in the axial direction, the fifth gap 55 may be perpendicular to the 1C intermediate straight portion 163. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the fifth gap 55 can be even more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the fifth gap 55 can even more effectively suppressed.

[0228] Furthermore, by arranging the shield pieces 37, 38 so that the seventh gap 57 crosses the 1D intermediate straight portion 164, the magnetic field lines formed around each 1D intermediate straight portion 164 are prevented from reaching the second shield member 40 through the seventh gap 57. This prevents the magnetic field lines formed around the 1D intermediate straight portion 164 from generating eddy currents in the second shield member 40. This means that an increase in loss (heat generation) of the coil unit 5 due to the presence of the seventh gap 57 can be suppressed, and that a decrease in performance of the coil unit 5 due to the presence of the seventh gap 57 can be suppressed.

[0229] As viewed in the axial direction, the angle formed by the seventh gap 57 and the 1D intermediate straight portion 164 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the seventh gap 57 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the seventh gap 57 can be effectively suppressed. Furthermore, as can be seen from FIG. 28 , as viewed in the axial direction, the seventh gap 57 may be perpendicular to the 1D intermediate straight portion 164. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the seventh gap 57 can be even more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the seventh gap 57 can even more effectively suppressed.

[0230] 28, the gaps 58, 52, 54, and 56 each traverse at least a portion of the first to fourth straight portion groups 11G to 14G when viewed in the axial direction. In the illustrated example, the gaps 58, 52, 54, and 56 each traverse the first to fourth straight portion groups 11G to 14G. In other words, when viewed in the axial direction, the gaps 58, 52, 54, and 56 each extend radially inward from the first to fourth straight portion groups 11G to 14G to the radially outward.

[0231] When viewed in the axial direction, the angle formed between the eighth gap 58 and the first linear portion 11 is 80° to 100°. More specifically, the eighth gap 58 is perpendicular to the first linear portion 11. When viewed in the axial direction, the angle formed between the second gap 52 and the second linear portion 12 is 80° to 100°. More specifically, the second gap 52 is perpendicular to the second linear portion 12. When viewed in the axial direction, the angle formed between the fourth gap 54 and the third linear portion 13 is 80° to 100°. More specifically, the fourth gap 54 is perpendicular to the third linear portion 13. When viewed in the axial direction, the angle formed between the sixth gap 56 and the fourth linear portion 14 is 80° to 100°. More specifically, the sixth gap 56 is perpendicular to the fourth linear portion 14.

[0232] 29, the angle formed between the gaps 50 crossing the first intermediate straight portion group 161G-164G and the first intermediate straight portions 161-164 is 80° to 100° when viewed in the axial direction. In the example shown in FIG. 28, the gaps 50 crossing the first intermediate straight portion group 161G-164G are perpendicular to the first intermediate straight portions 161-164 when viewed in the axial direction. In this way, various layouts (or various division modes) can be adopted for the layout of the multiple shielding pieces 30P (or various division modes of the first shielding member 30) so that the angle formed between the gaps 50 crossing the first intermediate straight portion group 161G-164G and the first intermediate straight portions 161-164 is 80° to 100°.

[0233] Next, a description will be given of modified examples shown in Figures 30 to 33. In the examples shown in Figures 30 to 33, the coil 10 includes a plurality of spiral-shaped coil elements 10j, 10jj, similar to the coil 10 shown in Figures 17 to 19.

[0234] The coil elements 10j, 10jj shown in Figures 30 to 33 have an octagonal shape overall, similar to the coil element 10i shown in Figures 26 to 29. The coil elements 10j, 10jj (electrical conductor 10E) are wound so that the turn portions 101 to 108 form a roughly octagonal shape.

[0235] In the example shown in FIGS. 30 to 33, the first to fifth turn portions 101 to 105 of each coil element 10j, 10jj include first intermediate straight portions 161 to 164 in addition to the first to third straight portions 11 to 13 and the plurality of turn connection portions 16. The 1A intermediate straight portion 161 and the 1C intermediate straight portion 163 extend in a third direction D3. The third direction D3 is non-parallel to any of the first to second directions D1 to D2. The 1B intermediate straight portion 162 and the 1D intermediate straight portion 164 extend in a fourth direction D4. The fourth direction D4 is non-parallel to any of the first to third directions D1 to D3.

[0236] In each of the turn portions 101-105 of each of the coil elements 10j, 10jj, adjacent ends of the first straight portion 11 and the second straight portion 12 are connected via a first-A intermediate straight portion 161. Similarly, in each of the turn portions 101-105 of each of the coil elements 10j, 10jj, adjacent ends of the second straight portion 12 and the third straight portion 13 are connected via a first-B intermediate straight portion 162. Furthermore, in each of the turn portions 101-105 of each of the coil elements 10j, 10jj, adjacent ends of the third straight portion 13 and the plurality of turn connection portions 16 are connected via a first-C intermediate straight portion 163. Furthermore, in each of the turn portions 101-105 of each of the coil elements 10j, 10jj, adjacent ends of the first straight portion 11 and the plurality of turn connection portions 16 are connected via a first-D intermediate straight portion 164.

[0237] In the examples shown in FIGS. 30 to 33, the first A intermediate straight portions 161 of the plurality of turn portions 101 to 105 are also radially arranged to form a first A intermediate straight portion group 161G. The first B intermediate straight portions 162 of the plurality of turn portions 101 to 105 are also radially arranged to form a first B intermediate straight portion group 162G. The first C intermediate straight portions 163 of the plurality of turn portions 101 to 105 are also radially arranged to form a first C intermediate straight portion group 163G. The first D intermediate straight portions 164 of the plurality of turn portions 101 to 105 are also radially arranged to form a first D straight portion group 164G. The radially adjacent first intermediate straight portions 161, 161; 162, 162; 163, 163; 164, 164 are radially spaced apart from each other. The 1A to 1D intermediate straight line portion groups 161G to 164G are groups of parallel straight lines made up of a plurality of 1A to 1D intermediate straight line portions 161 to 164, respectively.

[0238] As described above, the coil elements 10j, 10jj have an octagonal shape as a whole. The coil elements 10j, 10jj (electrical conductor 10E) are wound so that the turn portions 101-105 form a roughly octagonal shape. In other words, the coil elements 10j, 10jj include seven straight line portion groups 11-13, 161-164 extending along seven of the eight sides of the octagon. In the illustrated example, the angle between the first straight line portion 11 and the 1A intermediate straight line portion 161 is 125° to 145° when viewed in the axial direction. The angle between the 1A intermediate straight line portion 161 and the second straight line portion 12 is 125° to 145° when viewed in the axial direction. The angle between the second straight line portion 12 and the 1B intermediate straight line portion 162 is 125° to 145° when viewed in the axial direction. Furthermore, when viewed in the axial direction, the angle formed between the 1B intermediate straight portion 162 and the third straight portion 13 is 125° to 145°. When viewed in the axial direction, the angle formed between the third straight portion 13 and the 1C intermediate straight portion 163 is 125° to 145°. When viewed in the axial direction, the angle formed between the 1D intermediate straight portion 164 and the first straight portion 11 is 125° to 145°.

[0239] In particular, in the example shown in FIGS. 30 to 33 , the angle formed between the first straight portion 11 and the 1A intermediate straight portion 161 is 135° when viewed in the axial direction. The angle formed between the 1A intermediate straight portion 161 and the second straight portion 12 is also 135° when viewed in the axial direction. The angle formed between the second straight portion 12 and the 1B intermediate straight portion 162 is also 135° when viewed in the axial direction. The angle formed between the 1B intermediate straight portion 162 and the third straight portion 13 is also 135° when viewed in the axial direction. The angle formed between the third straight portion 13 and the 1C intermediate straight portion 163 is also 135° when viewed in the axial direction. The angle formed between the 1D intermediate straight portion 164 and the first straight portion 11 is also 135° when viewed in the axial direction.

[0240] 30 to 33, the coil elements 10j, 10jj have a regular octagonal shape as a whole. The coil elements 10j, 10jj (electrical conductor 10E) are wound so that the turn portions 101 to 105 form a regular octagon. In other words, the coil elements 10j, 10jj include seven straight line portion groups 11 to 13, 161 to 164 that extend along seven of the eight sides of the regular octagon. This can improve the performance of the coil 10.

[0241] 30 to 33, the circumferentially adjacent straight portions 11-13 and the first intermediate straight portions 161-164 may be connected by a curved portion. Also, the circumferentially adjacent firstC intermediate straight portion 163 and the turn connecting portion 16 may be connected by a curved portion. Also, the circumferentially adjacent firstD intermediate straight portion 164 and the turn connecting portion 16 may be connected by a curved portion.

[0242] 30, the first shield member 30 includes nine shield pieces 30P. Twelve gaps 50 are formed in the first shield member 30. In the example shown in Fig. 30, when viewed in the axial direction, the 12 gaps 50 traverse at least a portion of the first to third straight portion groups 11G to 13G and / or the 1A to 1D intermediate straight portion groups 161G to 164G of each coil element 10j, 10jj.

[0243] In the example shown in FIG. 31 , the first shield member 30 includes 12 shield pieces 30P. Seventeen gaps 50 are formed in the first shield member 30. In the example shown in FIG. 31 , 13 of the 17 gaps 50 cross at least a portion of the first to third straight portion groups 11G to 13G and / or the 1A to 1D intermediate straight portion groups 161G to 164G of each coil element 10j, 10jj when viewed in the axial direction. One of the 13 gaps 50 crosses the second straight portion group 12G of each coil element 10j, 10jj. In the example shown in FIG. 31 , when viewed in the axial direction, the angle formed between the gap 50 crossing the second straight portion group 12G and the second straight portion group 12G is 80° to 100°, more specifically, 90°.

[0244] 31 , one of the 17 gaps 50 extends along the first straight portion group 11G within the first straight portion group 11G of each coil element 10j, 10jj. The gap 50 extending within the first straight portion group 11G extends closer to the central axis C (inward in the radial direction) than the smallest integer-th first straight portion 11, counting from the innermost first straight portion 11 (the first straight portion 11 of the first turn portion 101) among the plurality of first straight portions 11 in the first straight portion group 11G, that is equal to or greater than the value obtained by dividing the total number of the plurality of first straight portions 11 by 3.

[0245] 31 , one of the 17 gaps 50 extends along the third straight portion group 13G within the third straight portion group 13G of each coil element 10j, 10jj. The gap 50 extending within the third straight portion group 13G extends closer to the central axis C (inward in the radial direction) than the smallest integer-th third straight portion 13 that is equal to or greater than the value obtained by dividing the total number of the plurality of third straight portions 13 by 3, counting from the innermost third straight portion 13 (the third straight portion 13 of the first turn portion 101) among the plurality of third straight portions 13 in the third straight portion group 13G.

[0246] In the example shown in FIG. 32, similar to the example shown in FIG. 28, the first shield member 30 includes eight shield pieces 31 to 38. Each of the shield pieces 31 to 38 has a triangular shape. More specifically, each of the shield pieces 31 to 38 has a right-angled triangular shape. First to eighth gaps 51 to 58 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31 extend radially from the central axis C. When viewed in the axial direction, the gaps 51, 53, 55, and 57 cross at least a portion of the 1A-1D intermediate straight portion groups 161G to 164G of each coil element 10j, 10jj, respectively. In the illustrated example, the gaps 51, 53, 55, and 57 cross the 1A-1D intermediate straight portion groups 161G-164G of each coil element 10j, 10jj, respectively, when viewed in the axial direction. In other words, the gaps 51, 53, 55, and 57 extend radially inwardly and radially outwardly of the 1A-1D intermediate straight portion groups 161G-164G of each coil element 10j, 10jj, respectively, when viewed in the axial direction. This prevents magnetic field lines formed around each of the first intermediate straight portions 161-164 of each coil element 10j, 10jj from reaching the second shield member 40 through the gaps 51, 53, 55, or 57 that cross the first intermediate straight portions 161-164.

[0247] When viewed in the axial direction, the angle formed between the first gap 51 and the 1A intermediate straight portion 161 of each coil element 10j, 10jj may be, for example, 80° to 100°. Furthermore, as can be seen from Fig. 32, when viewed in the axial direction, the first gap 51 may be perpendicular to the 1A intermediate straight portion 161 of each coil element 10j, 10jj.

[0248] When viewed in the axial direction, the angle formed by the third gap 53 and the 1B intermediate straight portion 162 of each coil element 10j, 10jj may be, for example, 80° to 100°. Furthermore, as can be seen from Fig. 32, when viewed in the axial direction, the third gap 53 may be perpendicular to the 1B intermediate straight portion 162 of each coil element 10j, 10jj.

[0249] When viewed in the axial direction, the angle formed by the fifth gap 55 and the first C intermediate straight portion 163 of each coil element 10j, 10jj may be, for example, 80° to 100°. Furthermore, as can be seen from Fig. 32, when viewed in the axial direction, the fifth gap 55 may be perpendicular to the first C intermediate straight portion 163 of each coil element 10j, 10jj.

[0250] When viewed in the axial direction, the angle formed by the seventh gap 57 and the 1D intermediate straight portion 164 of each coil element 10j, 10jj may be, for example, 80° to 100°. Furthermore, as can be seen from Fig. 32, when viewed in the axial direction, the seventh gap 57 may be perpendicular to the 1D intermediate straight portion 164 of each coil element 10j, 10jj.

[0251] 32, the gaps 58, 52, 54 cross at least a portion of the first to third straight portion groups 11G to 13G of each of the coil elements 10j, 10jj, respectively, as viewed in the axial direction. In the illustrated example, the gaps 58, 52, 54 cross the first to third straight portion groups 11G to 13G of each of the coil elements 10j, 10jj, respectively. In other words, the gaps 58, 52, 54 extend radially inward to radially outward from the first to third straight portion groups 11G to 13G of each of the coil elements 10j, 10jj, respectively, as viewed in the axial direction.

[0252] When viewed in the axial direction, the angle formed between the eighth gap 58 and the first linear portion 11 of each coil element 10j, 10jj is 80° to 100°. More specifically, the eighth gap 58 is perpendicular to the first linear portion 11 of each coil element 10j, 10jj. When viewed in the axial direction, the angle formed between the second gap 52 and the second linear portion 12 of each coil element 10j, 10jj is 80° to 100°. More specifically, the second gap 52 is perpendicular to the second linear portion 12 of each coil element 10j, 10jj. When viewed in the axial direction, the angle formed between the fourth gap 54 and the third linear portion 13 of each coil element 10j, 10jj is 80° to 100°. More specifically, the fourth gap 54 is perpendicular to the third linear portion 13 of each coil element 10j, 10jj.

[0253] 33, the angle formed by the gaps 50 crossing the first intermediate straight portion groups 161G-164G of each of the coil elements 10j, 10jj and the first intermediate straight portions 161-164 is 80° to 100° when viewed in the axial direction. In the example shown in FIG. 33, the gaps 50 crossing the first intermediate straight portion groups 161G-164G of each of the coil elements 10j, 10jj are perpendicular to the first intermediate straight portions 161-164 when viewed in the axial direction. In this way, various layouts (or various division modes) can be adopted for the layout of the multiple shield pieces 30P (or various division modes of the first shield member 30) so that the angle formed by the gaps 50 crossing the first intermediate straight portion groups 161G-164G of each of the coil elements 10j, 10jj and the first intermediate straight portions 161-164 is 80° to 100°.

[0254] Next, a description will be given of a modified example shown in Figures 34 and 35. In the example shown in Figures 34 and 35, first intermediate straight portion groups 161G, 162G, 163G, and 164G are connected to straight portion groups 12G, 13G, 14G, and 11G via second intermediate straight portion groups 171G, 172G, 173G, and 174G.

[0255] In the example shown in FIGS. 34 and 35, the coil element 10i includes a conductor 10E having a spiral shape. The conductor 10E includes a plurality of turn portions 101 to 107 arranged in the radial direction. In the example shown, the conductor 10E includes first to seventh turn portions 101 to 107. The first to seventh turn portions 101 to 107 are arranged in this order from the inside to the outside in the radial direction. In other words, the first turn portion 101 is located at the innermost position in the radial direction, and the seventh turn portion 107 is located at the outermost position in the radial direction. In yet other words, the first turn portion 101 forms the innermost portion of the coil element 10i. Furthermore, the seventh turn portion 107 forms the outermost portion of the coil element 10i.

[0256] The turn portions 101 to 107 of the coil element 10i extend on an imaginary plane perpendicular to the axial direction. The first to seventh turn portions 101 to 107 are connected in this order, so that the coil element 10i forms a spiral shape around the central axis C.

[0257] 34 and 35, the coil element 10i has a dodecagonal shape as a whole. The coil element 10i (electrical conductor 10E) is wound so that the turn portions 101 to 107 form a roughly dodecagonal shape.

[0258] Each of the turn portions 101 to 107 of the coil element 10i includes a plurality of straight portions 11 to 14 arranged around the central axis C. The straight portions 11 to 14 that are adjacent in the circumferential direction of a circle centered on the central axis C are connected to each other. In the illustrated example, the first to seventh turn portions 101 to 107 include a first straight portion 11 and a third straight portion 13 that extend in a first direction D1, and a second straight portion 12 and a fourth straight portion 14 that extend in a second direction D2.

[0259] The first direction D1 and the second direction D2 are not parallel to each other. In the example shown in Figures 34 and 35, the first direction D1 and the second direction D2 are perpendicular to each other. In each of the turn sections 101 to 107, the first straight section 11 and the third straight section 13 are arranged so that the central axis C passes therebetween. In each of the turn sections 101 to 107, the second straight section 12 and the fourth straight section 14 are arranged so that the central axis C passes therebetween.

[0260] In the example shown in FIGS. 34 and 35 , the first to seventh turn portions 101 to 107 include first intermediate linear portions 161 to 164 and second intermediate linear portions 171 to 174 in addition to the first to fourth linear portions 11 to 14. The 1A intermediate linear portion 161 and the 1C intermediate linear portion 163 extend in a third direction D3. The third direction D3 is non-parallel to any of the first to second directions D1 to D2. The 1B intermediate linear portion 162 and the 1D intermediate linear portion 164 extend in a fourth direction D4. The fourth direction D4 is non-parallel to any of the first to third directions D1 to D3. The 2A intermediate linear portion 171 and the 2C intermediate linear portion 173 extend in a fifth direction D5. The fifth direction D5 is non-parallel to any of the first to fourth directions D1 to D4. The secondB intermediate straight portion 172 and the secondD intermediate straight portion 174 extend in a sixth direction D6. The sixth direction D6 is not parallel to any of the first to fifth directions D1 to D5.

[0261] In each of the turn portions 101 to 107, adjacent ends of the first straight portion 11 and the second straight portion 12 are connected via a first intermediate straight portion 161. In each of the turn portions 101 to 107, adjacent ends of the first intermediate straight portion 161 and the second straight portion 12 are connected via a second intermediate straight portion 171.

[0262] In each of the turn portions 101 to 107, adjacent ends of the second straight portion 12 and the third straight portion 13 are connected via a first intermediate straight portion 162. In each of the turn portions 101 to 107, adjacent ends of the first intermediate straight portion 162 and the third straight portion 13 are connected via a second intermediate straight portion 172.

[0263] In each of the turn portions 101 to 107, adjacent ends of the third straight portion 13 and the fourth straight portion 14 are connected via a first intermediate straight portion 163. In each of the turn portions 101 to 107, adjacent ends of the first intermediate straight portion 163 and the fourth straight portion 14 are connected via a second intermediate straight portion 173.

[0264] Furthermore, adjacent ends of the fourth straight portions 14 and the first straight portions 11 of the radially adjacent turn portions 101, 102;...; 106, 107 are connected via a first-dimensional intermediate straight portion 164. Also, adjacent ends of the first straight portions 164 and the first straight portions 11 of the radially adjacent turn portions 101, 102;...; 106, 107 are connected via a second-dimensional intermediate straight portion 174. For example, adjacent ends of the fourth straight portion 14 of the first turn portion 101 and the first straight portion 11 of the second turn portion 102 are connected via the first-dimensional intermediate straight portion 164 and the second-dimensional intermediate straight portion 174. Also, adjacent ends of the fourth straight portion 14 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103 are connected via the first-dimensional intermediate straight portion 164 and the second-dimensional intermediate straight portion 174.

[0265] The first A intermediate straight portions 161 of the plurality of turn portions 101-107 are arranged in the radial direction to form a first A intermediate straight portion group 161G. The first B intermediate straight portions 162 of the plurality of turn portions 101-107 are arranged in the radial direction to form a first B intermediate straight portion group 162G. The first C intermediate straight portions 163 of the plurality of turn portions 101-107 are arranged in the radial direction to form a first C intermediate straight portion group 163G. The first D intermediate straight portions 164 of the plurality of turn portions 101-107 are arranged in the radial direction to form a first D straight portion group 164G. The radially adjacent first intermediate straight portions 161, 161; 162, 162; 163, 163; 164, 164 are radially spaced apart from each other. The 1A to 1D intermediate straight line portion groups 161G to 164G are groups of parallel straight lines made up of a plurality of 1A to 1D intermediate straight line portions 161 to 164, respectively.

[0266] The second A intermediate straight portions 171 of the plurality of turn portions 101-107 are arranged in the radial direction to form a second A intermediate straight portion group 171G. The second B intermediate straight portions 172 of the plurality of turn portions 101-107 are arranged in the radial direction to form a second B intermediate straight portion group 172G. The second C intermediate straight portions 173 of the plurality of turn portions 101-107 are arranged in the radial direction to form a second C intermediate straight portion group 173G. The second D intermediate straight portions 174 of the plurality of turn portions 101-107 are arranged in the radial direction to form a second D straight portion group 174G. Radially adjacent second intermediate straight portions 171, 171; 172, 172; 173, 173; 174, 174 are radially spaced apart from each other. The 2A to 2D intermediate straight line portion groups 171G to 174G are groups of parallel straight lines made up of a plurality of 2A to 2D intermediate straight line portions 171 to 174, respectively.

[0267] As described above, the coil element 10i in FIGS. 34 and 35 has a dodecagonal shape as a whole. The coil element 10i (electrical conductor 10E) is wound so that the turn portions 101 to 107 form a roughly dodecagonal shape. In other words, the coil element 10i includes 12 straight line portion groups 11 to 14, 161 to 164, and 171 to 174 extending along 12 sides of the dodecagon. In the illustrated example, the angle between the first straight line portion 11 and the 1A intermediate straight line portion 161 is 140° to 160° when viewed in the axial direction. The angle between the first A intermediate straight line portion 161 and the 2A intermediate straight line portion 171 is 140° to 160° when viewed in the axial direction. The angle between the 2A intermediate straight line portion 171 and the 2A intermediate straight line portion 12 is 140° to 160° when viewed in the axial direction. Furthermore, when viewed in the axial direction, the angle formed between the second straight portion 12 and the first-B intermediate straight portion 162 is 140° to 160°. When viewed in the axial direction, the angle formed between the first-B intermediate straight portion 162 and the second-B intermediate straight portion 172 is 140° to 160°. When viewed in the axial direction, the angle formed between the second-B intermediate straight portion 172 and the third straight portion 13 is 140° to 160°. When viewed in the axial direction, the angle formed between the third straight portion 13 and the first-C intermediate straight portion 163 is 140° to 160°. When viewed in the axial direction, the angle formed between the first-C intermediate straight portion 163 and the second-C intermediate straight portion 173 is 140° to 160°. When viewed in the axial direction, the angle formed between the second-C intermediate straight portion 173 and the fourth straight portion 14 is 140° to 160°. Furthermore, when viewed in the axial direction, the angle formed between the fourth straight portion 14 and the first-D intermediate straight portion 164 is 140° to 160°. When viewed in the axial direction, the angle formed between the first-D intermediate straight portion 164 and the second-D intermediate straight portion 174 is 140° to 160°. When viewed in the axial direction, the angle formed between the second-D intermediate straight portion 174 and the first straight portion 11 is 140° to 160°.

[0268] In particular, in the example shown in FIGS. 34 and 35 , the angle formed between the first straight portion 11 and the 1A intermediate straight portion 161 is 150° when viewed in the axial direction. Furthermore, the angle formed between the 1A intermediate straight portion 161 and the 2A intermediate straight portion 171 is 150° when viewed in the axial direction. Furthermore, the angle formed between the 2A intermediate straight portion 171 and the second straight portion 12 is 150° when viewed in the axial direction. Furthermore, the angle formed between the second straight portion 12 and the 1B intermediate straight portion 162 is 150° when viewed in the axial direction. Furthermore, the angle formed between the 1B intermediate straight portion 162 and the 2B intermediate straight portion 172 is 150° when viewed in the axial direction. Furthermore, the angle formed between the 2B intermediate straight portion 172 and the third straight portion 13 is 150° when viewed in the axial direction. Furthermore, when viewed in the axial direction, the angle formed by the third straight portion 13 and the 1C intermediate straight portion 163 is 150°. When viewed in the axial direction, the angle formed by the 1C intermediate straight portion 163 and the 2C intermediate straight portion 173 is 150°. When viewed in the axial direction, the angle formed by the 2C intermediate straight portion 173 and the fourth straight portion 14 is 150°. When viewed in the axial direction, the angle formed by the fourth straight portion 14 and the 1D intermediate straight portion 164 is 150°. When viewed in the axial direction, the angle formed by the 1D intermediate straight portion 164 and the 2D intermediate straight portion 174 is 150°. When viewed in the axial direction, the angle formed by the 2D intermediate straight portion 174 and the first straight portion 11 is 150°.

[0269] 34 and 35, the coil element 10i may have a regular dodecagonal shape as a whole. The coil element 10i (electrical conductor 10E) may be wound so that the turn portions 101-107 form a regular dodecagon. In other words, the coil element 10i may include 12 straight line portion groups 11-14, 161-164, 171-174 extending along 12 sides of the regular dodecagon. In this case, the performance of the coil 10 can be improved.

[0270] 30 etc., when the coil 10 includes coil elements 10j, 10jj and the coil elements 10j, 10jj have a dodecagonal shape as a whole, each of the coil elements 10j, 10jj only needs to include eleven groups of straight line portions 11-13, 161-164, 171-174 extending along eleven of the twelve sides of the dodecagon. Similarly, when the coil 10 includes coil elements 10j, 10jj and the coil elements 10j, 10jj have a regular dodecagonal shape as a whole, each of the coil elements 10j, 10jj only needs to include eleven groups of straight line portions 11-13, 161-164, 171-174 extending along eleven of the twelve sides of the regular dodecagon.

[0271] In the examples shown in FIGS. 34 and 35, the straight line portions 11 to 14, the first intermediate straight line portions 161 to 164, and the second intermediate straight line portions 171 to 184 that are adjacent to each other in the circumferential direction may also be connected by curved lines.

[0272] 34, the first shield member 30 includes 18 shield pieces 30P. Each shield piece 30P has a rectangular shape. Twenty-four gaps 50 are formed in the first shield member 30. Twenty of the 24 gaps 50 cross at least a portion of the straight line portion groups 11G to 14G, the first intermediate straight line portion groups 161G to 164G, and / or the second intermediate straight line portion groups 171G to 174G when viewed in the axial direction.

[0273] In the example shown in FIG. 35, the first shield member 30 includes 24 shield pieces 30P. 28 gaps 50 are formed in the first shield member 30. 16 of the 28 gaps extend radially from the central axis C. Four of the 16 gaps cross at least a portion of the second intermediate straight portion group 171G-174G when viewed in the axial direction. In the example shown in FIG. 35, the four gaps 50 cross the second intermediate straight portion group 171G-174G when viewed in the axial direction. In other words, the four gaps 50 extend from radially inward to radially outward of the second intermediate straight portion group 171G-174G when viewed in the axial direction.

[0274] By arranging the shield pieces 30P so that one of the four gaps 50 crosses the second A intermediate straight portion 171, the magnetic field lines formed around each second A intermediate straight portion 171 are prevented from reaching the second shield member 40 through the gap 50. This prevents the magnetic field lines formed around the second A intermediate straight portion 171 from generating eddy currents in the second shield member 40. This means that it is possible to prevent an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50, and it is also possible to prevent a decrease in performance of the coil unit 5 due to the presence of the gap 50.

[0275] When viewed in the axial direction, the angle formed by the gap 50 crossing the 2A intermediate straight portion 171 and the 2A intermediate straight portion 171 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the gap 50 can be effectively suppressed. Furthermore, as can be seen from FIG. 35 , when viewed in the axial direction, the gap 50 may be perpendicular to the 2A intermediate straight portion 171. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50 can be even more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the gap 50 can even more effectively suppressed.

[0276] Furthermore, by arranging the shield pieces 30P so that one of the four gaps 50 crosses the secondB intermediate straight portion 172, the magnetic field lines formed around each secondB intermediate straight portion 172 are prevented from reaching the second shield member 40 through the gap 50. This makes it possible to prevent eddy currents from being generated in the second shield member 40 by the magnetic field lines formed around the secondB intermediate straight portion 172. This means that it is possible to prevent an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50, and it means that it is possible to prevent a decrease in performance of the coil unit 5 due to the presence of the gap 50.

[0277] When viewed in the axial direction, the angle formed by the gap 50 crossing the 2B intermediate straight portion 172 and the 2B intermediate straight portion 172 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the gap 50 can be effectively suppressed. Furthermore, as can be seen from FIG. 35 , when viewed in the axial direction, the gap 50 may be perpendicular to the 2B intermediate straight portion 172. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50 can be even more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the gap 50 can even more effectively suppressed.

[0278] Furthermore, by arranging the shield pieces 30P so that one of the four gaps 50 crosses the second-C intermediate straight portion 173, the magnetic field lines formed around each second-C intermediate straight portion 173 are prevented from reaching the second shield member 40 through the gap 50. This prevents the magnetic field lines formed around the second-C intermediate straight portion 173 from generating eddy currents in the second shield member 40. This means that it is possible to prevent an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50, and it is also possible to prevent a decrease in performance of the coil unit 5 due to the presence of the gap 50.

[0279] When viewed in the axial direction, the angle formed by the gap 50 crossing the second-C intermediate straight portion 173 and the second-C intermediate straight portion 173 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the gap 50 can be effectively suppressed. Furthermore, as can be seen from FIG. 35 , when viewed in the axial direction, the gap 50 may be perpendicular to the second-C intermediate straight portion 173. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50 can be even more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the gap 50 can even more effectively suppressed.

[0280] Furthermore, by arranging the shield pieces 30P so that one of the four gaps 50 crosses the second-dimensional intermediate straight portion 174, the magnetic field lines formed around each second-dimensional intermediate straight portion 174 are prevented from reaching the second shield member 40 through the gap 50. This prevents the magnetic field lines formed around the second-dimensional intermediate straight portion 174 from generating eddy currents in the second shield member 40. This means that it is possible to prevent an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50, and it is also possible to prevent a decrease in performance of the coil unit 5 due to the presence of the gap 50.

[0281] When viewed in the axial direction, the angle formed by the gap 50 crossing the 2D intermediate straight portion 174 and the 2D intermediate straight portion 174 may be, for example, 80° to 100°. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50 can be effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the gap 50 can be effectively suppressed. Furthermore, as can be seen from FIG. 35 , when viewed in the axial direction, the gap 50 may be perpendicular to the 2D intermediate straight portion 174. In this case, an increase in loss (heat generation) of the coil unit 5 due to the presence of the gap 50 can be even more effectively suppressed, and a deterioration in performance of the coil unit 5 due to the presence of the gap 50 can even more effectively suppressed.

[0282] 35, eight of the 16 gaps 50 cross at least a portion of any of the first to fourth straight portion groups 11G to 14G when viewed in the axial direction. In the illustrated example, the eight gaps 50 cross any of the first to fourth straight portion groups 11G to 14G. In other words, when viewed in the axial direction, the eight gaps 50 extend from radially inward to radially outward of any of the first to fourth straight portion groups 11G to 14G.

[0283] When viewed in the axial direction, the angle formed between the gap 50 crossing the first linear portion 11 and the first linear portion 11 is 80° to 100°. More specifically, the gap 50 is perpendicular to the first linear portion 11. When viewed in the axial direction, the angle formed between the gap 50 crossing the second linear portion 12 and the second linear portion 12 is 80° to 100°. More specifically, the gap 50 is perpendicular to the second linear portion 12. When viewed in the axial direction, the angle formed between the gap 50 crossing the third linear portion 13 and the third linear portion 13 is 80° to 100°. More specifically, the gap 50 is perpendicular to the third linear portion 13. When viewed in the axial direction, the angle formed between the gap 50 crossing the fourth linear portion 14 and the fourth linear portion 14 is 80° to 100°. More specifically, the gap 50 is perpendicular to the fourth linear portion 14 .

[0284] 35, four of the 16 gaps 50 cross at least a portion of any one of the 1A to 1D intermediate straight portion groups 161G to 164G when viewed in the axial direction. In the illustrated example, the four gaps 50 cross any one of the 1A to 1D intermediate straight portion groups 161G to 164G. In other words, when viewed in the axial direction, the four gaps 50 extend from radially inward to radially outward of any one of the 1A to 1D intermediate straight portion groups 161G to 164G.

[0285] When viewed in the axial direction, the angle formed by the gap 50 crossing the 1A intermediate straight portion 161 and the 1A intermediate straight portion 161 is 80° to 100°. More specifically, the gap 50 is perpendicular to the 1A intermediate straight portion 161. When viewed in the axial direction, the angle formed by the gap 50 crossing the 1B intermediate straight portion 162 and the 1B intermediate straight portion 162 is 80° to 100°. More specifically, the gap 50 is perpendicular to the 1B intermediate straight portion 162. When viewed in the axial direction, the angle formed by the gap 50 crossing the 1C intermediate straight portion 163 and the 1C intermediate straight portion 163 is 80° to 100°. More specifically, the gap 50 is perpendicular to the 1C intermediate straight portion 163. Further, when viewed in the axial direction, the angle formed by the gap 50 crossing the 1D intermediate straight portion 164 and the 1D intermediate straight portion 164 is 80° to 100°. More specifically, the gap 50 is perpendicular to the 1D intermediate straight portion 164.

[0286] The layout of the multiple shielding pieces 30P (or the division mode of the first shielding member 30) such that the angles formed between the gaps 50 crossing the second intermediate straight portion group 171G-174G and the second intermediate straight portions 171-174 are 80° to 100° is not limited to the layout (or the division mode) shown in Fig. 35. Even when the coil elements 10i; 10j, 10jj have a dodecagonal shape as a whole, various layouts (or various division modes) can be adopted as the layout of the multiple shielding pieces 30P (or the division mode of the first shielding member 30) such that the angles formed between the gaps 50 crossing the second intermediate straight portion group 171G-174G and the second intermediate straight portions 171-174 are 80° to 100°.

[0287] Next, modified examples shown in Fig. 36 and Fig. 37 will be described. In the example shown in Fig. 6A, when the first connection terminal 46 is connected to the inner end 10e1 of the coil element 10i, the first connection terminal 46 extends within the gap 50 when viewed in the axial direction, but this is not limited to this. As shown in Fig. 34 and Fig. 35, the first connection terminal 46 may extend within a notch N formed in the shield piece 30P when viewed in the axial direction. In this case as well, as shown in Fig. 7, the first connection terminal 46 may extend from the inside to the outside of the coil 10 at a height position where it overlaps with the shield piece 30P when viewed from the side of the coil unit 5.

[0288] Even when the first connection terminal 46 extends within the notch N formed in the shield piece 30P, the angle formed by the first connection terminal 46 and the straight portion 11 across which the first connection terminal 46 crosses when viewed in the axial direction may be, for example, 80° to 100°. Furthermore, as shown in Figures 36 and 37, the first connection terminal 46 may be perpendicular to the straight portion 11. In this case, magnetic field lines formed around the straight portion 11 are prevented from reaching the second shield member 40 through the notch N.

[0289] Next, modified examples shown in FIGS. 38 and 39 will be described. In the example shown in FIG. 38, compared to the example shown in FIG. 24, the overlap length between the shield piece 31 closest to the inner end 10e1 of the coil element 10i and the inner end region (the first straight portion 11 of the first turn portion 101 in the examples shown in FIGS. 24 and 38) is longer when viewed in the axial direction. In this case, the loss (heat generation) of the first shield member 30 in FIG. 38 (particularly, the loss of the shield piece 31) can be more effectively reduced than the loss (heat generation) of the first shield member 30 in FIG. 24 (particularly, the loss of the shield piece 31). Note that the loss of the first shield member 30 here includes loss (so-called "iron loss") caused by the magnetic flux of the first shield member 30.

[0290] 39, compared to the example shown in Fig. 29, the overlap length between the inner end region including the inner end 10e1 of the coil element 10i (the first straight portion 11 of the first turn portion 101 in the examples shown in Figs. 29 and 39) and the shield piece 3130P closest to the inner end 10e1 is longer when viewed in the axial direction. In this case, the loss (heat generation) of the first shield member 30 in Fig. 39 (particularly the loss of the shield piece 31) can be made smaller effectively than the loss (heat generation) of the first shield member 30 in Fig. 29 (particularly the loss of the shield piece 31).

[0291] Next, modifications shown in FIGS. 40 and 41 will be described. In the example shown in FIGS. 2 to 5B, the first connection terminal 46 connected to the inner end 10e1 of the coil element 10i extends radially outward from the coil 10, crossing one of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. However, this is not limited to this. As shown in FIG. 40, the first connection terminal 46 may extend radially outward from the coil 10, crossing one of the 1A to 1D intermediate curved line groups 151G to 154G when viewed in the axial direction. In this case, it is easy to bring the first connection terminal 46 close to the second connection terminal 47. In other words, it is easy to set the distance between the first point IP1 and the second point IP2 to 100 mm or less, or 50 mm or less. Therefore, it is easy to set the angle θ between the first virtual line IL1 and the second virtual line IL2 to 90° or less, or 60° or less, 45° or less, or 30° or less.

[0292] 40, the angle formed between the first connection terminal 46 and the tangent line TL4 of the first intermediate curved portion group 154G, which the first connection terminal 46 crosses, may be, for example, 80° to 100°, as viewed in the axial direction. Furthermore, as can be seen from Fig. 40, the first connection terminal 46 may be perpendicular to the tangent line TL4 of the first intermediate curved portion group 154G, as viewed in the axial direction. In this case, the magnetic field lines formed around the turn portions 101 to 108 of the coil 10 are prevented from reaching the second shield member 40 through the gap 50 or notch N through which the first connection terminal 46 passes.

[0293] 41, the first connection terminal 46 may extend radially outward from the coil 10, crossing one of the intermediate straight portion groups 161G-164G or 171G-174G when viewed in the axial direction. In this case, it is easy to bring the first connection terminal 46 close to the second connection terminal 47. In other words, it is easy to set the distance between the first point IP1 and the second point IP2 to 100 mm or less, or 50 mm or less. Therefore, it is easy to set the angle θ between the first imaginary line IL1 and the second imaginary line IL2 to 90° or less, or 60° or less, 45° or less, or 30° or less.

[0294] 41, the angle formed between the first connection terminal 46 and the intermediate straight portion group 164G across which the first connection terminal 46 crosses may be, for example, 80° to 100° when viewed in the axial direction. Furthermore, as can be seen from Fig. 41, the first connection terminal 46 may be perpendicular to the intermediate straight portion group 164G when viewed in the axial direction. In this case, the magnetic field lines formed around each of the turn portions 101 to 108 of the coil 10 are prevented from reaching the second shield member 40 through the gap 50 or notch N through which the first connection terminal 46 passes.

[0295] Next, a modified example shown in Fig. 42 will be described. In the example shown in Figs. 2 to 5B, the pitches of the multiple turn portions 101 to 108 are equal. Therefore, the distance between the inner end portion 10e1 of the coil element 10i and the first straight portion 11 of the second turn portion 102 is equal to the distance between the first straight portion 11 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103. In contrast, in the example shown in Fig. 42, the distance between the inner end portion 10e1 of the coil element 10i and the first straight portion 11 of the second turn portion 102 is greater than the distance between the first straight portion 11 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103. More specifically, the distance between the inner end region of the coil element 10i including the inner end 10e1 (in the example shown in FIG. 42, the first straight portion 11 of the first turn portion 101) and the first straight portion 11 of the second turn portion 102 is greater than the distance between the first straight portion 11 of the second turn portion 102 and the first straight portion 11 of the third turn portion 103. In an example in which the first connection terminal 46 is connected to the inner end 10e1 of the coil element 10i, the distance between the inner end 10e1 and the second turn portion 102 can suppress loss (heat generation) (loss including so-called iron loss) in the first shield member 30. In particular, the loss (heat generation) in the shield piece 30P (in the example shown in FIG. 42, the shield piece 31) that overlaps the inner end region of the coil element 10i (in the example shown in FIG. 42, the first straight portion 11 of the first turn portion 101) when viewed in the axial direction can be effectively suppressed.

[0296] <<Second embodiment>> Next, a second embodiment and its modified examples will be described with reference to Fig. 43. The coil unit 5 shown in Fig. 43 differs from the coil unit 5 shown in Fig. 26 in that the first shield member 30 is not divided into multiple shield pieces 30P. The other configurations are substantially the same as those of the coil unit 5 shown in Fig. 26. In the second embodiment shown in Fig. 43, parts that are the same as those of the coil unit 5 shown in Fig. 26 are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0297] 43, similar to the example shown in FIG. 26, the coil element 10i is octagonal as a whole. More specifically, the coil element 10i includes eight straight line portion groups (straight line portion groups 11G-14G and intermediate straight line portion groups 161G-164G) extending along the eight sides of the octagon. This improves the performance of the coil unit 5 compared to when the coil element 10i has the shape shown in FIGS. 2 to 5B. In other words, the performance of the coil unit 5 including the coil element 10i having an octagonal shape as a whole is higher than that of the coil unit 5 including the coil element 10i having a rectangular shape as a whole and including the first intermediate curved line portion groups 151G-154G.

[0298] In the example shown in Fig. 43, the angle formed by adjacent straight line portion groups 11G, 161G; 161G, 12G; 12G, 162G; 162G, 13G; 13G, 163G; 163G, 14G; 14G, 164G; 164G, 11G may be 125° to 145°. In the example shown in Fig. 43, the angle formed by adjacent straight line portion groups 11G, 161G; 161G, 12G; 12G, 162G; 162G, 13G; 13G, 163G; 163G, 14G; 14G, 164G; 164G, 11G may be 135°. In addition, in the example shown in Fig. 43, the coil element 10i may be a regular octagon as a whole. According to the knowledge obtained by the inventors of the present invention, the performance of the coil unit 5 can be effectively improved by forming the coil 10 in a regular octagonal shape.

[0299] In the example shown in FIG. 43, the first shield member 30 is not divided into multiple shield pieces 30P. Therefore, no gaps 50 are formed in the first shield member 30. Of course, when the coil elements 10i are octagonal as a whole, the first shield member 30 may be divided into multiple shield pieces 30P as shown in FIGS. 26 to 29. Even when the first shield member 30 is divided into multiple shield pieces 30P, the performance of a coil unit 5 including coil elements 10i having an octagonal shape as a whole is higher than that of a coil unit 5 including coil elements 10i having the shapes shown in FIGS. 2 to 5B, provided that all conditions other than the shape of the coil elements 10i are the same. For example, the performance of the coil unit 5 shown in FIG. 28 is higher than that of the coil unit 5 shown in FIG. 22. Furthermore, the performance of the coil unit 5 shown in FIG. 29 is higher than that of the coil unit 5 shown in FIG. 24.

[0300] <<Modifications>> Various modifications can be made to the second embodiment described above. Modifications of the second embodiment will be described below with reference to Figures 44 and 45.

[0301] In the example shown in Fig. 44, similar to the examples shown in Figs. 30 to 33, the coil elements 10j, 10jj are octagonal as a whole. More specifically, the coil elements 10j, 10jj include seven straight line portion groups (straight line portion groups 11G to 13G and intermediate straight line portion groups 161G to 164G) extending along seven of the eight sides of the octagon. This improves the performance of the coil unit 5 compared to when the coil elements 10j, 10jj have the shapes shown in Figs. 17 to 21. In other words, the performance of the coil unit 5 including the coil elements 10j, 10jj that are octagonal as a whole is higher than that of the coil unit 5 including the coil elements 10j, 10jj that are rectangular as a whole and include first intermediate curved portions 151G to 154G.

[0302] In the example shown in Fig. 44, the angle formed by adjacent straight line portion groups 11G, 161G; 161G, 12G; 12G, 162G; 162G, 13G; 13G, 163G; 164G, 11G may be 125° to 145°. In the example shown in Fig. 44, the angle formed by adjacent straight line portion groups 11G, 161G; 161G, 12G; 12G, 162G; 162G, 13G; 13G, 163G; 164G, 11G may be 135°. In addition, in the example shown in Fig. 44, the coil elements 10j, 10jj may be a regular octagon as a whole. More specifically, the coil elements 10j, 10jj may include seven straight line portion groups (straight line portion groups 11G-13G and first intermediate straight line portion groups 161G-164G) extending along seven of the eight sides of the regular octagon. According to the findings of the present inventors, the regular octagonal shape of the coil 10 can effectively improve the performance of the coil unit 5.

[0303] In the example shown in FIG. 44, the first shield member 30 is not divided into multiple shield pieces 30P. Therefore, no gaps 50 are formed in the first shield member 30. Of course, when the coil elements 10j, 10jj have an octagonal shape as a whole, the first shield member 30 may be divided into multiple shield pieces 30P as shown in FIGS. 30 to 33. Even when the first shield member 30 is divided into multiple shield pieces 30P, if the conditions other than the shape of the coil elements 10j, 10jj are the same, the performance of a coil unit 5 including coil elements 10j, 10jj having an octagonal shape as a whole is higher than the performance of a coil unit 5 including coil elements 10j, 10jj having the shapes shown in FIGS. 17 to 19. For example, the performance of the coil unit 5 shown in FIG. 31 is higher than the performance of the coil unit 5 shown in FIG. 21.

[0304] In the example shown in FIG. 45, similar to the examples shown in FIGS. 34 and 35, the coil element 10i has a dodecagonal shape as a whole. More specifically, the coil element 10i includes eleven straight line portion groups (straight line portion groups 11G to 13G, first intermediate straight line portion groups 161G to 164G, and second intermediate straight line portion groups 171G to 174G) extending along eleven of the twelve sides of the dodecagon. In the example shown in FIG. 45, the coil element 10i includes straight line portion groups (straight line portion groups 11G to 14G, first intermediate straight line portion groups 161G to 164G, and second intermediate straight line portion groups 171G to 174G) extending along the twelve sides of the dodecagon. This can improve the performance of the coil unit 5 compared to when the coil element 10i has the shape shown in FIGS. 2 to 5B. That is, the performance of the coil unit 5 including the coil elements 10i that are dodecagonal as a whole is higher than that of the coil unit 5 including the coil elements 10i that are quadrangular as a whole and include the first intermediate curved portions 151G to 154G.

[0305] In the example shown in Fig. 45, the angle formed by adjacent straight line portion groups 11G, 161G; 161G, 171G; 171G, 12G; 12G, 162G; 162G, 172G; 172G, 13G; 13G, 163G; 163G, 173G; 164G, 174G; 174G, 11G may be 125° to 145°. In the example shown in Fig. 45, the angle formed by adjacent straight line portion groups 173G, 14G; 14G, 164G may also be 125° to 145°. In the example shown in Fig. 45, the angle formed by adjacent straight line portion groups 11G, 161G; 161G, 171G; 171G, 12G; 12G, 162G; 162G, 172G; 172G, 13G; 13G, 163G; 163G, 173G; 164G, 174G; 174G, 11G may be 135°. In the example shown in Fig. 45, the angle formed by adjacent straight line portion groups 173G, 14G; 14G, 164G may also be 135°. Furthermore, in the example shown in Fig. 45, the coil element 10i may be a regular dodecagon as a whole. More specifically, the coil element 10i may include 11 straight line portion groups (straight line portion groups 11G-13G, first intermediate straight line portion groups 161G-164G, and second intermediate straight line portion groups 171G-174G) extending along 11 of the 12 sides of the regular dodecagon. According to the findings of the present inventors, the coil 10 having a regular dodecagon shape can effectively improve the performance of the coil unit 5.

[0306] 45, the first shield member 30 is not divided into multiple shield pieces 30P. Therefore, no gaps 50 are formed in the first shield member 30. Of course, when the coil elements 10i have a dodecagonal shape as a whole, the first shield member 30 may be divided into multiple shield pieces 30P as shown in FIGS. 34 and 35. Even when the first shield member 30 is divided into multiple shield pieces 30P, if the conditions other than the shape of the coil elements 10i are the same, the performance of a coil unit 5 including coil elements 10i having a dodecagonal shape as a whole is higher than the performance of a coil unit 5 including coil elements 10i having the shapes shown in FIGS. 2 to 5B.

[0307] 45, the coil element 10i includes 12 straight line portion groups (straight line portion groups 11G-14G, first intermediate straight line portion groups 161G-164G, and second intermediate straight line portion groups 171G-174G) extending along the 12 sides of the dodecagon. However, when the coil 10 includes coil elements 10j, 10jj as shown in FIG. 30 and other figures, and the coil elements 10j, 10jj have a dodecagonal shape as a whole, each of the coil elements 10j, 10jj only needs to include 11 straight line portion groups 11-13, 161-164, 171-174 extending along 11 of the 12 sides of the dodecagon. Similarly, when coil 10 includes coil elements 10j, 10jj, and the coil elements 10j, 10jj have an overall regular dodecagonal shape, each coil element 10j, 10jj may include 11 groups of straight line portions 11-13, 161-164, 171-174 extending along 11 of the 12 sides of the regular dodecagon.

[0308] <<Example 1>> Next, the difference in loss of the coil unit 5 due to the difference in the position of the gap 50 formed in the first shield member 30 will be described.

[0309] <Example 1-1> As the coil unit 5 of Example 1-1, a coil unit 5 was prepared, which consisted of a spirally formed coil 10, a magnetic resin layer 20, a first shielding member 30, and a second shielding member 40, as shown in Figures 2 to 5B. The coil 10 was formed similarly to the coil 10 shown in Figures 2 to 5B. The coil 10 was formed of copper, and had a line width of 6 mm and a thickness of 0.5 mm. The distance between adjacent turn portions 101, 102;...; 107, 108 was 6 mm. The dimensions of the coil 10 along the first direction D1 and the second direction D2 were 295 mm and 295 mm, respectively. The magnetic resin layer 20 was formed by curing a two-component curing epoxy resin mixed with magnetic powder. The coil 10 was housed in a recess 25 of the magnetic resin layer 20 as shown in FIG. 4, and the second main surface 10b of the coil 10 was in close contact with the magnetic resin layer 20. The first shielding member 30 was formed by dividing it into four shielding pieces 31 to 34. Each of the shielding pieces 31 to 34 was a ferrite plate. The dimensions of the first shielding member 30 in the first direction D1 and the second direction D2 were 300 mm and 300 mm, respectively. The distance between the magnetic resin layer 20 and the first shielding member 30 was 1 mm. The width of the gaps 50 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 31 was 5 mm. One of the four gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 31 (first gap 51) crossed the first linear portions 11 of the second to eighth turn portions 102 to 108 when viewed in the axial direction. This gap 50 was perpendicular to the first linear portions 11 of the second to eighth turn portions 102 to 108 when viewed in the axial direction. The other three gaps 50 (second to fourth gaps 52 to 54) crossed the second to fourth linear portions 12 to 14 of the first to eighth turn portions 101 to 108, respectively, when viewed in the axial direction. When viewed in the axial direction, these three gaps 50 were perpendicular to the second to fourth straight portions 12 to 14 of the first to eighth turn portions 101 to 108, respectively. The four gaps 50 (first to fourth gaps 51 to 54) were formed so that their extension lines passed through the central axis C. The second shielding member 40 was made of aluminum. The dimensions of the second shielding member 40 in the first direction D1 and the second direction D2 were 320 mm and 320 mm, respectively. The distance between the first shielding member 30 and the second shielding member 40 was 1 mm.

[0310] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Example 1-1 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Example 1-1 were 121.0 and 87.7 W, respectively.

[0311] <Example 1-2> A coil unit 5 of Example 1-2 was produced in the same manner as in Example 1-1, except that the first shield member 30 was formed by dividing it into six shield pieces 31 to 36, similar to the example shown in FIG. Each of the shielding pieces 31 to 36 was a ferrite plate. The width of the gap 50 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 was 5 mm. Two of the seven gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 crossed the first straight portions 11 of the second to eighth turn portions 102 to 108 or the third straight portions 13 of the first to eighth turn portions 101 to 108 when viewed in the axial direction. These two gaps 50 were perpendicular to the first straight portions 11 of the second to eighth turn portions 102 to 108 or the third straight portions 13 of the first to eighth turn portions 101 to 108 when viewed in the axial direction. Furthermore, these two gaps 50 were formed so that their extensions passed through the central axis C. One of the seven gaps 50 extends along the second direction D2 within the region surrounded by the first turn portion 101. This gap 50 overlaps with the central axis C when viewed in the axial direction. The remaining four gaps 50 crossed the second straight portions 12 or the fourth straight portions 14 of the first to eighth turn portions 101 to 108 when viewed in the axial direction. These four gaps 50 were perpendicular to the second straight portions 12 or the fourth straight portions 14 of the first to eighth turn portions 101 to 108 when viewed in the axial direction. Two of these four gaps 50 extended between the first straight portion group 11G and the central axis C when viewed in the axial direction. The other two of these four gaps 50 extended between the third straight portion group 13G and the central axis C when viewed in the axial direction.

[0312] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Example 1-2 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Example 1-2 were 115.0 and 91.3 W, respectively.

[0313] <Examples 1-3> As shown in FIG. 12, the coil unit 5 of Example 1-3 was fabricated in the same manner as in Example 1-1, except that the first shield member 30 was formed by dividing it into six shield pieces 31 to 36. Each of the shielding pieces 31 to 36 was a ferrite plate. The width of the gap 50 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 was 5 mm. Two of the seven gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 crossed the first straight portions 11 of the second to eighth turn portions 102 to 108 or the third straight portions 13 of the first to eighth turn portions 101 to 108 when viewed in the axial direction. These two gaps 50 were perpendicular to the first straight portions 11 of the second to eighth turn portions 102 to 108 or the third straight portions 13 of the first to eighth turn portions 101 to 108 when viewed in the axial direction. Furthermore, these two gaps 50 were formed so that their extensions passed through the central axis C. One of the seven gaps 50 extends along the second direction D2 within the region surrounded by the first turn portion 101. This gap 50 overlaps with the central axis C when viewed in the axial direction. Furthermore, three of the remaining four gaps 50 extended along the second direction D2 when viewed in the axial direction, and overlapped with the first straight portion 11 or the third straight portion 13 of the first turn portion 101. Furthermore, the other of these four gaps 50 extended on an extension of the first straight portion 11 when viewed in the axial direction.

[0314] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Example 1-3 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of the coil 10 of Example 1-3 were 102.0 and 99.5 W, respectively.

[0315] <Examples 1-4> As shown in FIG. 13, the coil unit 5 of Example 1-4 was fabricated in the same manner as in Example 1-1, except that the first shield member 30 was formed by dividing it into six shield pieces 31 to 36. Each of the shielding pieces 31 to 36 was a ferrite plate. The width of the gap 50 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 was 5 mm. Of the seven gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35, three of these gaps 50 crossed a portion of the first linear portion 11 of the second to eighth turn portions 102-108 and / or a portion of the third linear portion 13 of the first to eighth turn portions 101-108 when viewed in the axial direction. These three gaps 50 were perpendicular to a portion of the first linear portion 11 of the second to eighth turn portions 102-108 and / or a portion of the third linear portion 13 of the first to eighth turn portions 101-108 when viewed in the axial direction. One of these three gaps 50 overlapped with the central axis C when viewed in the axial direction. The other two of these three gaps 50 were formed so that their extensions passed through the central axis C. Furthermore, two of the remaining four gaps 50 extended along the first straight portion 11 within the first straight portion group 11G when viewed in the axial direction. More specifically, these gaps 50 extended between the first straight portion 11 of the second turn portion 102 and the third turn portion 103. Furthermore, the other two of the four gaps 50 extended along the third straight portion 13 within the third straight portion group 13G when viewed in the axial direction. More specifically, these gaps 50 extended between the third straight portion 13 of the second turn portion 102 and the third turn portion 103.

[0316] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Example 1-4 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Example 1-4 were 94.5 and 104.0 W, respectively.

[0317] <Examples 1-5> As shown in FIG. 14, the coil unit 5 of Example 1-5 was fabricated in the same manner as in Example 1-1, except that the first shield member 30 was formed by dividing it into six shield pieces 31 to 36. Each of the shielding pieces 31 to 36 was a ferrite plate. The width of the gap 50 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 was 5 mm. Of the seven gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35, three of these gaps 50 crossed a portion of the first linear portion 11 of the second to eighth turn portions 102-108 and / or a portion of the third linear portion 13 of the first to eighth turn portions 101-108 when viewed in the axial direction. These three gaps 50 were perpendicular to a portion of the first linear portion 11 of the second to eighth turn portions 102-108 and / or a portion of the third linear portion 13 of the first to eighth turn portions 101-108 when viewed in the axial direction. One of these three gaps 50 overlapped with the central axis C when viewed in the axial direction. The other two of these three gaps 50 were formed so that their extensions passed through the central axis C. Furthermore, two of the remaining four gaps 50 extended along the first straight portion 11 within the first straight portion group 11G when viewed in the axial direction. More specifically, these gaps 50 extended between the first straight portion 11 of the third turn portion 103 and the fourth turn portion 104. Furthermore, the other two of the four gaps 50 extended along the third straight portion 13 within the third straight portion group 13G when viewed in the axial direction. More specifically, these gaps 50 extended between the third straight portion 13 of the third turn portion 103 and the fourth turn portion 104.

[0318] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Example 1-5 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Example 1-5 were 89.7 and 103.0 W, respectively.

[0319] <Examples 1-6> As shown in FIG. 15, the coil unit 5 of Example 1-6 was fabricated in the same manner as in Example 1-1, except that the first shield member 30 was formed by dividing it into six shield pieces 31 to 36. Each of the shielding pieces 31 to 36 was a ferrite plate. The width of the gap 50 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 was 5 mm. Of the seven gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35, three of these gaps 50 crossed a portion of the first linear portion 11 of the second to eighth turn portions 102-108 and / or a portion of the third linear portion 13 of the first to eighth turn portions 101-108 when viewed in the axial direction. These three gaps 50 were perpendicular to a portion of the first linear portion 11 of the second to eighth turn portions 102-108 and / or a portion of the third linear portion 13 of the first to eighth turn portions 101-108 when viewed in the axial direction. One of these three gaps 50 overlapped with the central axis C when viewed in the axial direction. The other two of these three gaps 50 were formed so that their extensions passed through the central axis C. Furthermore, two of the remaining four gaps 50 extended along the first straight portion 11 within the first straight portion group 11G when viewed in the axial direction. More specifically, these gaps 50 extended between the first straight portion 11 of the sixth turn portion 106 and the seventh turn portion 107. Furthermore, the other two of the four gaps 50 extended along the third straight portion 13 within the third straight portion group 13G when viewed in the axial direction. More specifically, these gaps 50 extended between the third straight portion 13 of the sixth turn portion 106 and the seventh turn portion 107.

[0320] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Example 1-6 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Examples 1-6 were 95.4 and 100.0 W, respectively.

[0321] <Examples 1-7> As shown in FIG. 16, the coil unit 5 of Example 1-7 was fabricated in the same manner as in Example 1-1, except that the first shield member 30 was formed by dividing it into six shield pieces 31 to 36. Each of the shielding pieces 31 to 36 was a ferrite plate. The width of the gap 50 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35 was 5 mm. Of the seven gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 31; 32, 35, three of these gaps 50 crossed a portion of the first linear portion 11 of the second to eighth turn portions 102-108 and / or a portion of the third linear portion 13 of the first to eighth turn portions 101-108 when viewed in the axial direction. These three gaps 50 were perpendicular to a portion of the first linear portion 11 of the second to eighth turn portions 102-108 and / or a portion of the third linear portion 13 of the first to eighth turn portions 101-108 when viewed in the axial direction. One of these three gaps 50 overlapped with the central axis C when viewed in the axial direction. The other two of these three gaps 50 were formed so that their extensions passed through the central axis C. Furthermore, two of the remaining four gaps 50 extended along the first straight portion 11 within the first straight portion group 11G when viewed in the axial direction. More specifically, these gaps 50 overlapped with the first straight portion 11 of the eighth turn portion 108. Furthermore, the other two of the four gaps 50 extended along the third straight portion 13 within the third straight portion group 13G when viewed in the axial direction. More specifically, these gaps 50 overlapped with the third straight portion 13 of the eighth turn portion 108.

[0322] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Example 1-7 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Example 1-7 were 120.5 and 88.0 W, respectively.

[0323] FIG. 46 shows the Q values and losses of the coil units 5 of Examples 1-1 to 1-7.

[0324] 46, the number of gaps 50 in the first shielding member 30 in the coil unit 5 of Example 1-2 is greater than the number of gaps 50 in the first shielding member 30 in the coil unit 5 of Example 1-1, but there was no significant difference in the Q value and loss between the coil units 5 of Examples 1-1 and 1-2. From this result, it can be understood that when the gaps 50 in the first shielding member 30 are arranged so as to cross the group of straight portions of the coil element 10i when viewed in the axial direction, the presence of these gaps 50 does not significantly impair the performance of the coil 10, and does not significantly increase the loss of the coil unit 5.

[0325] Furthermore, from the results of Examples 1-1 to 1-7, it can be seen that the Q value of a coil unit (coil unit 5 of Examples 1-1 and 1-2) in which, when viewed in the axial direction, all of the gaps 50 in the first shielding member 30 are formed to cross one of the straight section groups 11G to 14G tends to be higher than the Q value of a coil unit (coil unit 5 of Examples 1-3 to 1-7) in which some of the gaps 50 in the first shielding member 30 extend within one of the straight section groups 11G to 14G parallel to the straight sections 11 to 14 that make up that straight section group 11G to 14G.

[0326] Furthermore, from the results of Examples 1-3 to 1-7, it can be understood that when the gap 50 formed in the first shielding member 30 extends within any of the straight section groups 11G to 14G when viewed in the axial direction along the straight sections 11 to 14 that constitute that straight section group 11G to 14G, the Q value of the coil unit 5 becomes lower as the gap 50 approaches the radial center of the straight section group 11G to 14G.

[0327] Furthermore, from the results of Examples 1-2 to 1-7, it can be seen that the Q value of a coil unit (coil unit 5 of Example 1-2) in which, when viewed in the axial direction, the gap 50 in the first shielding member 30 is formed so as to extend between the first turn portion 101 that forms the innermost periphery of the coil 10 and the central axis C tends to be higher than the Q value of a coil unit (coil unit 5 of Examples 1-3 to 1-7) in which the gap 50 in the first shielding member 30 is formed so as to extend outward beyond the first turn portion 101 that forms the innermost periphery of the coil 10.

[0328] Furthermore, from the results of Examples 1-1 to 1-7, it can be seen that the Q value of a coil unit (coil unit 5 of Example 1-1) formed so that the extension line of the gap 50 of the first shielding member 30 overlaps with the central axis C when viewed in the axial direction tends to be higher than the Q value of a coil unit (coil unit 5 of Examples 1-2 to 1-7) formed so that the extension line of the gap 50 of the first shielding member 30 deviates from the central axis C.

[0329] <<Example 2>> Next, the difference in loss of the coil unit 5 due to the difference in the distance between the second main surface 10b of the coil 10 and the magnetic resin layer 20 will be described.

[0330] <Example 2-1> As the coil unit 5 of Example 2-1, a coil unit 5 was prepared, which consisted of a coil 10 including spirally formed coil elements 10j, 10jj, a magnetic resin layer 20, a first shielding member 30, and a second shielding member 40, as shown in Figures 17 to 19. The coil 10 was formed similarly to the coil 10 shown in Figures 17 to 19. The coil elements 10j, 10jj were formed of copper, with a line width of 6 mm and a thickness of 0.5 mm. In each coil element 10j, 10jj, the distance between adjacent turn portions 101, 102;...; 104, 105 was 6 mm. The dimensions of the coil 10 along the first direction D1 and the second direction D2 were 295 mm and 295 mm, respectively. The magnetic resin layer 20 was formed by curing a two-component curing epoxy resin mixed with magnetic powder. The coil 10 was embedded in the magnetic resin layer 20, as shown in FIG. 18, and the second main surface 10b of the coil 10 was in close contact with the magnetic resin layer 20. The first shielding member 30 was formed by dividing it into nine small shielding pieces 31 to 39. Each of the small shielding pieces 31 to 39 was a ferrite plate. The dimensions of the first shielding member 30 in the first direction D1 and the second direction D2 were 300 mm and 300 mm, respectively. The distance between the magnetic substance resin layer 20 and the first shielding member 30 was 0 mm. That is, the magnetic substance resin layer 20 and the first shielding member 30 were in close contact with each other. The width of the gaps 50 between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31; 32, 39; 34, 39; 36, 39; 38, 39 was 5 mm. Two of the twelve gaps 50 formed between adjacent shield pieces 31, 32; 32, 33; 33, 34; 34, 35; 35, 36; 36, 37; 37, 38; 38, 31; 32, 39; 34, 39; 36, 39; 38, 39 crossed the first straight portions 11 of the first to fifth turn portions 101 to 105 when viewed in the axial direction. These two gaps were perpendicular to the first linear portions 11 of the first to fifth turn portions 101 to 105 when viewed in the axial direction. Two of the twelve gaps 50 crossed the second linear portions 12 of the first to fifth turn portions 101 to 105 when viewed in the axial direction. These two gaps 50 were perpendicular to the second linear portions 12 of the first to fifth turn portions 101 to 105 when viewed in the axial direction. Two of the twelve gaps 50 crossed the third linear portions 13 of the first to fifth turn portions 101 to 105 when viewed in the axial direction. These two gaps 50 were perpendicular to the third linear portions 13 of the first to fifth turn portions 101 to 105 when viewed in the axial direction. Two of the twelve gaps 50 crossed the turn connection portions 16 of the first to fourth turn portions 101 to 104 when viewed in the axial direction. Furthermore, four of the twelve gaps 50 extend in the first direction D1 or the second direction D2 radially inward of the first turn portion 101 located at the innermost position when viewed in the axial direction. The second shielding member 40 was made of aluminum. The dimensions of the second shielding member 40 in the first direction D1 and the second direction D2 were 320 mm and 320 mm, respectively. The distance between the first shielding member 30 and the second shielding member 40 was 1 mm.

[0331] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Example 2-1 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Example 2-1 were 121.2 and 87.7 W, respectively.

[0332] <Example 2-2> The coil unit 5 of Example 2-2 was fabricated in the same manner as in Example 2-1, except that the distance between the magnetic resin layer 20 and the first shield member 30 was set to 1 mm.

[0333] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Example 2-2 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Example 2-2 were 122.0 and 85.0 W, respectively.

[0334] <Comparative Example 2-1> The coil unit 5 of Comparative Example 2-1 was produced in the same manner as in Example 2-1, except that the magnetic resin layer 20 was disposed at a distance from the coil 10. The distance between the second main surface 10b of the coil 10 and the magnetic resin layer 20 was 0.1 mm.

[0335] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Comparative Example 2-1 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Comparative Example 2-1 were 90.5 and 116.3 W, respectively.

[0336] <Comparative Example 2-2> The coil unit 5 of Comparative Example 2-2 was produced in the same manner as in Comparative Example 2-1, except that the distance between the second main surface 10b of the coil 10 and the magnetic resin layer 20 was set to 1 mm.

[0337] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Comparative Example 2-2 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Comparative Example 2-2 were 96.6 and 106.4 W, respectively.

[0338] <Comparative Example 2-3> A coil unit 5 of Comparative Example 2-3 was produced in the same manner as in Example 2-1, except that the magnetic resin layer 20 was not provided.

[0339] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Comparative Example 2-3 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Comparative Example 2-3 were 97.0 and 105.2 W, respectively.

[0340] <Comparative Example 2-4> Coil unit 5 of Comparative Example 2-4 was fabricated in the same manner as in Comparative Example 2-3, except that the distance between first shield member 30 and second shield member 40 was set to 6 mm.

[0341] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Comparative Example 2-4 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Comparative Example 2-4 were 104.0 and 100.9 W, respectively.

[0342] <Comparative Example 2-5> Coil unit 5 of Comparative Example 2-5 was fabricated in the same manner as in Comparative Example 2-3, except that the distance between first shield member 30 and second shield member 40 was set to 10 mm.

[0343] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Comparative Example 2-5 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Comparative Example 2-5 were 106.0 and 99.6 W, respectively.

[0344] <Comparative Example 2-6> Coil unit 5 of Comparative Example 2-6 was fabricated in the same manner as in Comparative Example 2-3, except that the distance between first shield member 30 and second shield member 40 was set to 15 mm.

[0345] (evaluation) Next, a high frequency current of 85 kHz was applied to the coil 10 of the coil unit 5 of Comparative Example 2-6 thus fabricated, and the Q value and loss of the coil unit 5 were measured. The Q value and loss of the coil unit 5 of Comparative Example 2-6 were 108.0 and 98.3 W, respectively.

[0346] FIG. 47 shows the Q values and losses of the coil units of Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-6.

[0347] As can be seen from FIG. 47, the loss of the coil unit 5 of Example 2-1 was significantly lower than the loss of the coil units 5 of Comparative Examples 2-1 and 2-2. This shows that the loss of the coil unit 5 can be significantly reduced by closely contacting the second main surface 10b of the coil 10 and the magnetic resin layer 20. In other words, when the second main surface 10b of the coil 10 and the magnetic resin layer 20 are spaced apart, the loss of the coil unit 5 increases significantly even if the distance between the second main surface 10b and the magnetic resin layer 20 is as small as 0.1 mm. Furthermore, there was no significant difference in the loss of the coil unit 5 between Example 2-1 and Example 2-2. This shows that when the second main surface 10b of the coil 10 and the magnetic resin layer 20 are closely contacted, the increase in loss of the coil unit 5 caused by bringing the first shield member 30 closer to the coil 10 can be suppressed. By comparing the losses of the coil units 5 of the comparative examples 2-3 to 2-6, it is clear that the loss of the coil unit 5 increases when the second shield member 40 is brought closer to the first shield member 30.

[0348] <<Examples 3 to 6>> Next, differences in the performance of the coil unit 5 due to differences in the shape of the coil 10 will be described.

[0349] <Example 3-1> As the coil unit 5 of Example 3-1, a coil unit 5 was prepared, which consisted of a spirally formed coil 10, a magnetic resin layer 20, a first shielding member 30, and a second shielding member 40, as shown in Figures 2 to 5B. The coil 10 was formed similarly to the coil 10 shown in Figures 2 to 5B. The coil 10 was formed of copper, and had a line width of 6 mm and a thickness of 0.5 mm. The distance between adjacent turn portions 101, 102;...; 107, 108 was 6 mm. The dimensions of the coil 10 along the first direction D1 and the second direction D2 were 295 mm and 295 mm, respectively. The magnetic resin layer 20 was formed by curing a two-component curing epoxy resin mixed with magnetic powder. The coil 10 was housed in a recess 25 of the magnetic resin layer 20 as shown in FIG. 4, and the second main surface 10b of the coil 10 was in close contact with the magnetic resin layer 20. The first shielding member 30 was not divided into multiple shielding pieces 30P. In other words, no gaps 50 were formed in the first shielding member 30. The first shielding member 30 was a ferrite plate. The dimensions of the first shielding member 30 in the first direction D1 and the second direction D2 were 300 mm and 300 mm, respectively. The distance between the magnetic resin layer 20 and the first shielding member 30 was 1 mm. The second shielding member 40 was made of aluminum. The dimensions of the second shielding member 40 in the first direction D1 and the second direction D2 were 320 mm and 320 mm, respectively. The distance between the first shielding member 30 and the second shielding member 40 was 1 mm.

[0350] <Example 3-2> The coil unit 5 of Example 3-2 was fabricated in the same manner as in Example 3-1, except that the first shielding member 30 was divided into nine shielding pieces 30P as in the example shown in Fig. 36. The first shielding member 30 was divided into three in the first direction D1 and three in the second direction D2. Each shield piece 30P was a ferrite plate. All nine shield pieces 30P were rectangular. The dimensions of the nine shield pieces 30P in the first direction D1 were equal to each other. The dimensions of the nine shield pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Eight of the twelve gaps 50 formed between adjacent shield pieces 30P crossed any of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13. When viewed in the axial direction, the gaps 50 crossing the fourth straight line portion group 14G were perpendicular to the fourth straight line portion 14. The remaining four gaps 50 extend between any of the first to fourth straight portion groups 11G to 14G and the central axis C along the first direction D1 or the second direction D2 when viewed in the axial direction.

[0351] <Example 3-3> The coil unit 5 of Example 3-3 was fabricated in the same manner as in Example 3-1, except that the first shielding member 30 was divided into 12 shielding pieces 30P. The first shielding member 30 was divided into four in the first direction D1 and into three in the second direction D2. Each shielding piece 30P was a ferrite plate. All twelve shielding pieces 30P were rectangular. The dimensions of the twelve shielding pieces 30P in the first direction D1 were equal to each other. The dimensions of the twelve shielding pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Two of the 17 gaps 50 formed between adjacent shield pieces 30P crossed the first straight line portion group 11G or the third straight line portion group 13G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13. Twelve of the 17 gaps 50 partially crossed any one of the 1A to 1D intermediate curved portions 151G to 154G when viewed in the axial direction. When viewed in the axial direction, the angle formed between the gap 50 crossing the first intermediate curved portion group 151G and a tangent line TL1 to the 1A intermediate curved portion group 151G was 45°. When viewed in the axial direction, the angle formed between the gap 50 crossing the 1B intermediate curved portion group 152G and a tangent line TL2 to the 1B intermediate curved portion group 152G was 45°. When viewed in the axial direction, the angle formed between the gap 50 crossing the 1C intermediate curved portion group 153G and a tangent line TL3 to the 1C intermediate curved portion group 153G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing the first-dimensional intermediate curved portion group 154G and the tangent line TL4 of the first-dimensional intermediate curved portion group 154G was 45°. Two of the 17 gaps 50 extended along the second direction D2 within the second straight portion group 12G or the fourth straight portion group 14G when viewed in the axial direction. These gaps 50 overlapped with the second straight portion 12 or the fourth straight portion 14 of the second turn portion 102. The remaining gap 50 extended along the second direction D2 between the second straight portion group 12G and the fourth straight portion group 14G as viewed in the axial direction. This gap 50 overlapped with the central axis C as viewed in the axial direction.

[0352] <Example 3-4> 2, the coil unit 5 of Example 3-4 was fabricated in the same manner as in Example 3-1, except that the first shielding member 30 was divided into four shielding pieces 30P. The first shielding member 30 was divided into two in the first direction D1 and two in the second direction D2. Each shielding piece 30P was a ferrite plate. All four shielding pieces 30P were rectangular. The dimensions of the four shielding pieces 30P in the first direction D1 were equal to each other. The dimensions of the four shielding pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. The four gaps 50 formed between adjacent shield pieces 30P crossed any of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. The gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11 when viewed in the axial direction. The gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12 when viewed in the axial direction. The gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13 when viewed in the axial direction. The gaps 50 crossing the fourth straight line portion group 14G were perpendicular to the fourth straight line portion 14 when viewed in the axial direction. The four gaps 50 were formed so that their extensions passed through the central axis C.

[0353] <Examples 3-5> 22, the coil unit 5 of Example 3-5 was fabricated in the same manner as in Example 3-1, except that the first shielding member 30 was divided into eight shielding pieces 30P. The eight gaps 50 formed in the first shielding member 30 extended radially from the central axis C when viewed in the axial direction. Each shield piece 30P was a ferrite plate. All eight shield pieces 30P were right-angled triangles. The dimensions of the eight shield pieces 30P in the first direction D1 were equal to each other. The dimensions of the eight shield pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Four of the eight gaps 50 formed between adjacent shield pieces 30P crossed any of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. The gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11 when viewed in the axial direction. The gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12 when viewed in the axial direction. The gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13 when viewed in the axial direction. The gaps 50 crossing the fourth straight line portion group 14G were perpendicular to the fourth straight line portion 14 when viewed in the axial direction. These four gaps 50 were formed so that their extensions passed through the central axis C. The remaining four gaps crossed one of the 1A to 1D intermediate curve portion groups 151G to 154G when viewed in the axial direction. The gap 50 crossing the 1A intermediate curve portion group 151G was perpendicular to the tangent TL1 of the 1A intermediate curve portion group 151G when viewed in the axial direction. The gap 50 crossing the 1B intermediate curve portion group 152G was perpendicular to the tangent TL2 of the 1B intermediate curve portion group 152G when viewed in the axial direction. The gap 50 crossing the 1C intermediate curve portion group 153G was perpendicular to the tangent TL3 of the 1C intermediate curve portion group 153G when viewed in the axial direction. The gap 50 crossing the 1D intermediate curve portion group 154G was perpendicular to the tangent TL4 of the 1D intermediate curve portion group 154G when viewed in the axial direction. These four gaps 50 were formed so that their extensions passed through the central axis C.

[0354] <Examples 3-6> As shown in FIG. 38, the coil unit 5 of Example 3-6 was fabricated in the same manner as in Example 3-1, except that the first shield member 30 was divided into 12 shield pieces 30P. Each shield piece 30P was a ferrite plate. Four of the 12 shield pieces 30P were square. The remaining eight shield pieces 30P were right-angled triangles. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Eight of the 13 gaps 50 formed between adjacent shield pieces 30P crossed any of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. The gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11 when viewed in the axial direction. The gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12 when viewed in the axial direction. The gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13 when viewed in the axial direction. The gaps 50 crossing the fourth straight line portion group 14G were perpendicular to the fourth straight line portion 14 when viewed in the axial direction. These four gaps 50 were formed so that their extensions passed through the central axis C. Four of the thirteen gaps 50 crossed any of the 1A to 1D intermediate curved portion groups 151G to 154G when viewed in the axial direction. The gaps 50 crossing the 1A intermediate curved portion group 151G were perpendicular to the tangent TL1 of the 1A intermediate curved portion group 151G when viewed in the axial direction. The gaps 50 crossing the 1B intermediate curved portion group 152G were perpendicular to the tangent TL2 of the 1B intermediate curved portion group 152G when viewed in the axial direction. The gaps 50 crossing the 1C intermediate curved portion group 153G were perpendicular to the tangent TL3 of the 1C intermediate curved portion group 153G when viewed in the axial direction. The gaps 50 crossing the 1D intermediate curved portion group 154G were perpendicular to the tangent TL4 of the 1D intermediate curved portion group 154G when viewed in the axial direction. The remaining gap 50 extended along the second direction D2 between the second straight portion group 12G and the fourth straight portion group 14G as viewed in the axial direction. This gap 50 overlapped with the central axis C as viewed in the axial direction.

[0355] <Examples 3-7> As shown in FIG. 24, the coil unit 5 of Example 3-7 was fabricated in the same manner as in Example 3-1, except that the first shield member 30 was divided into 13 shield pieces 30P. Each shield piece 30P was a ferrite plate. Five of the thirteen shield pieces 30P were square. The remaining eight shield pieces 30P were right-angled triangles. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Nine of the 14 gaps 50 formed between adjacent shield pieces 30P crossed any of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13. When viewed in the axial direction, the gaps 50 crossing the fourth straight line portion group 14G were perpendicular to the fourth straight line portion 14. Four of the 14 gaps 50 crossed any of the 1A to 1D intermediate curved portion groups 151G to 154G when viewed in the axial direction. The gaps 50 crossing the 1A intermediate curved portion group 151G were perpendicular to the tangent TL1 of the 1A intermediate curved portion group 151G when viewed in the axial direction. The gaps 50 crossing the 1B intermediate curved portion group 152G were perpendicular to the tangent TL2 of the 1B intermediate curved portion group 152G when viewed in the axial direction. The gaps 50 crossing the 1C intermediate curved portion group 153G were perpendicular to the tangent TL3 of the 1C intermediate curved portion group 153G when viewed in the axial direction. The gaps 50 crossing the 1D intermediate curved portion group 154G were perpendicular to the tangent TL4 of the 1D intermediate curved portion group 154G when viewed in the axial direction. The remaining gap 50 extended along the second direction D2 between the second straight portion group 12G and the fourth straight portion group 14G as viewed in the axial direction. This gap 50 overlapped with the central axis C as viewed in the axial direction.

[0356] (Evaluation of Example 3) An 85 kHz high-frequency current was passed through the coil 10 of the coil units 5 of Examples 3-1 to 3-7 fabricated in this manner, and the Q value, loss, impedance, and inductance of the coil units 5 were measured. The measurement results are shown in FIG. 48. In FIG. 48, "Q value," "impedance," and "inductance" refer to the Q value, impedance, and inductance of the coil unit 5. "SLD2" refers to the second shield member 40. "Joule loss" refers to the loss caused by the current in the coil 10 or the second shield member 40. "Iron loss" refers to the loss caused by the magnetic flux of the first shield member 30. "Total loss" is the sum of "Joule loss" and "Iron loss." "NP" refers to the number of divisions of the first shield member 30 (the number of shield pieces 30P included in the first shield member 30). For example, "NP9" means that the first shield member 30 is divided into nine pieces, and "NP12" means that the first shield member 30 is divided into twelve pieces. However, "NP1" means that the first shield member 30 is not divided.

[0357] <Example 4-1> The coil unit 5 of Example 4-1 was fabricated in the same manner as in Example 3-1, except that the coil elements 10i were formed into a regular octagonal shape as a whole, as in the example shown in Fig. 43. The first shielding member 30 was not divided into a plurality of shielding pieces 30P. In other words, no gaps 50 were formed in the first shielding member 30. The coil 10 was made of copper and had a wire width of 6 mm and a thickness of 0.5 mm. The distance between adjacent turn portions 101, 102;...; 107, 108 was 6 mm. The dimensions of the coil 10 along the first direction D1 and the second direction D2 were 295 mm and 295 mm, respectively. The first shielding member 30 was a ferrite plate. The dimensions of the first shielding member 30 in the first direction D1 and the second direction D2 were 300 mm and 300 mm, respectively.

[0358] <Example 4-2> The coil unit 5 of Example 4-2 was fabricated in the same manner as in Example 4-1, except that the first shielding member 30 was divided into nine shielding pieces 30P in the same manner as in Example 3-2. The first shielding member 30 was divided into three in the first direction D1 and three in the second direction D2. Each shield piece 30P was a ferrite plate. All nine shield pieces 30P were rectangular. The dimensions of the nine shield pieces 30P in the first direction D1 were equal to each other. The dimensions of the nine shield pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. The 12 gaps 50 formed between adjacent shield pieces 30P crossed at least a portion of any of the first to fourth straight portion groups 11G to 14G and the 1A to 1D intermediate straight portion groups 161G to 164G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing at least a portion of the first straight portion group 11G were perpendicular to the first straight portion 11. When viewed in the axial direction, the gaps 50 crossing at least a portion of the second straight portion group 12G were perpendicular to the second straight portion 12. When viewed in the axial direction, the gaps 50 crossing at least a portion of the third straight portion group 13G were perpendicular to the third straight portion 13. When viewed in the axial direction, the gaps 50 crossing at least a portion of the fourth straight portion group 14G were perpendicular to the fourth straight portion 14. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1A intermediate straight portion group 161G and the 1A intermediate straight portion group 161G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1B intermediate straight portion group 162G and the 1B intermediate straight portion group 162G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1C intermediate straight portion group 163G and the 1C intermediate straight portion group 163G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1D intermediate straight portion group 164G and the 1D intermediate straight portion group 164G was 45°.

[0359] <Example 4-3> The coil unit 5 of Example 4-3 was fabricated in the same manner as in Example 4-1, except that the first shielding member 30 was divided into 12 shielding pieces 30P in the same manner as in Example 3-3. The first shielding member 30 was divided into four in the first direction D1 and into three in the second direction D2. Each shielding piece 30P was a ferrite plate. All twelve shielding pieces 30P were rectangular. The dimensions of the twelve shielding pieces 30P in the first direction D1 were equal to each other. The dimensions of the twelve shielding pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Of the 17 gaps 50 formed between adjacent shield pieces 30P, 16 crossed at least a portion of either the first to fourth straight portion groups 11G to 14G or the 1A to 1D intermediate straight portion groups 161G to 164G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing at least a portion of the first straight portion group 11G were perpendicular to the first straight portion 11. When viewed in the axial direction, the gaps 50 crossing at least a portion of the second straight portion group 12G were perpendicular to the second straight portion 12. When viewed in the axial direction, the gaps 50 crossing at least a portion of the third straight portion group 13G were perpendicular to the third straight portion 13. When viewed in the axial direction, the gaps 50 crossing at least a portion of the fourth straight portion group 14G were perpendicular to the fourth straight portion 14. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1A intermediate straight portion group 161G and the 1A intermediate straight portion group 161G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1B intermediate straight portion group 162G and the 1B intermediate straight portion group 162G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1C intermediate straight portion group 163G and the 1C intermediate straight portion group 163G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1D intermediate straight portion group 164G and the 1D intermediate straight portion group 164G was 45°. The remaining gap 50 extended along the second direction D2 between the second straight portion group 12G and the fourth straight portion group 14G as viewed in the axial direction. This gap 50 overlapped with the central axis C as viewed in the axial direction.

[0360] <Example 4-4> The coil unit 5 of Example 4-4 was fabricated in the same manner as in Example 4-1, except that the first shielding member 30 was divided into four shielding pieces 30P in the same manner as in Example 3-4. The first shielding member 30 was divided into two in the first direction D1 and two in the second direction D2. Each shielding piece 30P was a ferrite plate. All four shielding pieces 30P were rectangular. The dimensions of the four shielding pieces 30P in the first direction D1 were equal to each other. The dimensions of the four shielding pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. The four gaps 50 formed between adjacent shield pieces 30P crossed any of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13. When viewed in the axial direction, the gaps 50 crossing the fourth straight line portion group 14G were perpendicular to the fourth straight line portion 14. The four gaps 50 were formed so that their extensions passed through the central axis C.

[0361] <Example 4-5> The coil unit 5 of Example 4-5 was produced in the same manner as in Example 4-1, except that the first shielding member 30 was divided into eight shielding pieces 30P in the same manner as in Example 3-5. The eight gaps 50 formed in the first shielding member 30 extended radially from the central axis C when viewed in the axial direction. Each shield piece 30P was a ferrite plate. All eight shield pieces 30P were right-angled triangles. The dimensions of the eight shield pieces 30P in the first direction D1 were equal to each other. The dimensions of the eight shield pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Four of the eight gaps 50 formed between adjacent shield pieces 30P crossed any of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. The gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11 when viewed in the axial direction. The gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12 when viewed in the axial direction. The gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13 when viewed in the axial direction. The gaps 50 crossing the fourth straight line portion group 14G were perpendicular to the fourth straight line portion 14 when viewed in the axial direction. These four gaps 50 were formed so that their extensions passed through the central axis C. The remaining four gaps crossed any of the 1A to 1D intermediate straight portion groups 161G to 164G when viewed in the axial direction. The gap 50 crossing the 1A intermediate straight portion group 161G was perpendicular to the 1A intermediate straight portion group 161G when viewed in the axial direction. The gap 50 crossing the 1B intermediate straight portion group 162G was perpendicular to the 1B intermediate straight portion group 162G when viewed in the axial direction. The gap 50 crossing the 1C intermediate straight portion group 163G was perpendicular to the 1C intermediate straight portion group 163G when viewed in the axial direction. The gap 50 crossing the 1D intermediate straight portion group 164G was perpendicular to the 1D intermediate straight portion group 164G when viewed in the axial direction. These four gaps 50 were formed so that their extensions passed through the central axis C.

[0362] <Examples 4-6> The coil unit 5 of Example 4-6 was fabricated in the same manner as in Example 4-1, except that the first shield member 30 was divided into 12 shield pieces 30P in the same manner as in Example 3-6. Each shield piece 30P was a ferrite plate. Four of the 12 shield pieces 30P were square. The remaining eight shield pieces 30P were right-angled triangles. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Eight of the 13 gaps 50 formed between adjacent shield pieces 30P crossed any of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. The gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11 when viewed in the axial direction. The gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12 when viewed in the axial direction. The gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13 when viewed in the axial direction. The gaps 50 crossing the fourth straight line portion group 14G were perpendicular to the fourth straight line portion 14 when viewed in the axial direction. These four gaps 50 were formed so that their extensions passed through the central axis C. Four of the thirteen gaps 50 crossed any of the 1A to 1D intermediate straight portion groups 161G to 164G when viewed in the axial direction. The gaps 50 crossing the 1A intermediate straight portion group 161G were perpendicular to the 1A intermediate straight portion group 161G when viewed in the axial direction. The gaps 50 crossing the 1B intermediate straight portion group 162G were perpendicular to the 1B intermediate straight portion group 162G when viewed in the axial direction. The gaps 50 crossing the 1C intermediate straight portion group 163G were perpendicular to the 1C intermediate straight portion group 163G when viewed in the axial direction. The gaps 50 crossing the 1D intermediate straight portion group 164G were perpendicular to the 1D intermediate straight portion group 164G when viewed in the axial direction. The remaining gap 50 extended along the second direction D2 between the second straight portion group 12G and the fourth straight portion group 14G as viewed in the axial direction. This gap 50 overlapped with the central axis C as viewed in the axial direction.

[0363] <Examples 4-7> The coil unit 5 of Example 4-7 was fabricated in the same manner as in Example 4-1, except that the first shield member 30 was divided into 13 shield pieces 30P in the same manner as in Example 3-7. Each shield piece 30P was a ferrite plate. Five of the thirteen shield pieces 30P were square. The remaining eight shield pieces 30P were right-angled triangles. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Nine of the 14 gaps 50 formed between adjacent shield pieces 30P crossed any of the first to fourth straight line portion groups 11G to 14G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13. When viewed in the axial direction, the gaps 50 crossing the fourth straight line portion group 14G were perpendicular to the fourth straight line portion 14. Four of the 14 gaps 50 crossed any of the 1A to 1D intermediate curved portion groups 151G to 154G when viewed in the axial direction. The gaps 50 crossing the 1A intermediate curved portion group 151G were perpendicular to the tangent TL1 of the 1A intermediate curved portion group 151G when viewed in the axial direction. The gaps 50 crossing the 1B intermediate curved portion group 152G were perpendicular to the tangent TL2 of the 1B intermediate curved portion group 152G when viewed in the axial direction. The gaps 50 crossing the 1C intermediate curved portion group 153G were perpendicular to the tangent TL3 of the 1C intermediate curved portion group 153G when viewed in the axial direction. The gaps 50 crossing the 1D intermediate curved portion group 154G were perpendicular to the tangent TL4 of the 1D intermediate curved portion group 154G when viewed in the axial direction. The remaining gap 50 extended along the second direction D2 between the second straight portion group 12G and the fourth straight portion group 14G as viewed in the axial direction. This gap 50 overlapped with the central axis C as viewed in the axial direction.

[0364] (Evaluation of Example 4) An 85 kHz high-frequency current was passed through the coil 10 of the coil units 5 of Examples 4-1 to 4-7 fabricated in this manner, and the Q value, loss, impedance, and inductance of the coil units 5 were measured. The measurement results are shown in FIG. 49. In FIG. 49, "Q value," "impedance," and "inductance" refer to the Q value, impedance, and inductance of the coil unit 5. "SLD2" refers to the second shield member 40. "Joule loss" refers to the loss caused by the current in the coil 10 or the second shield member 40. "Iron loss" refers to the loss caused by the magnetic flux of the first shield member 30. "Total loss" is the sum of "Joule loss" and "Iron loss." "NP" refers to the number of divisions of the first shield member 30 (the number of shield pieces 30P included in the first shield member 30). For example, "NP9" means that the first shield member 30 is divided into nine pieces, and "NP12" means that the first shield member 30 is divided into twelve pieces. However, "NP1" means that the first shield member 30 is not divided.

[0365] (Comparison of Example 3 and Example 4) FIG. 50 shows the Q values of the coil units 5 of Examples 3-1 to 3-7 and Examples 4-1 to 4-7. In FIG. 50, E3-1 to E3-7 refer to Examples 3-1 to 3-7, respectively. Also, in FIG. 50, E4-1 to E4-7 refer to Examples 4-1 to 4-7, respectively. It can be seen from FIG. 50 that, other conditions being the same, the Q value of a coil unit 5 including a coil 10 that is octagonal as a whole is higher than the Q value of a coil unit 5 including a coil 10 that is rectangular as a whole and includes first intermediate curved portions 151G to 154G.

[0366] <Example 5-1> Next, as the coil unit 5 of Example 5-1, a coil unit 5 was prepared, which consisted of a coil 10 including spirally formed coil elements 10j, 10jj, a magnetic resin layer 20, a first shielding member 30, and a second shielding member 40, as shown in Figures 17 to 19. The coil 10 was formed similarly to the coil 10 shown in Figures 17 to 19. The coil elements 10j, 10jj were formed of copper, with a line width of 6 mm and a thickness of 0.5 mm. In each coil element 10j, 10jj, the distance between adjacent turn portions 101, 102;...; 104, 105 was 6 mm. The dimensions of the coil 10 along the first direction D1 and the second direction D2 were 295 mm and 295 mm, respectively. The magnetic resin layer 20 was formed by curing a two-component curing epoxy resin mixed with magnetic powder. The coil 10 was embedded in the magnetic resin layer 20, as shown in FIG. 18, and the second main surface 10b of the coil 10 was in close contact with the magnetic resin layer 20. The first shielding member 30 was not divided into multiple shielding pieces 30P. In other words, no gaps 50 were formed in the first shielding member 30. The first shielding member 30 was a ferrite plate. The dimensions of the first shielding member 30 in the first direction D1 and the second direction D2 were 300 mm and 300 mm, respectively. The distance between the magnetic substance resin layer 20 and the first shielding member 30 was 0 mm. That is, the magnetic substance resin layer 20 and the first shielding member 30 were in close contact with each other. The second shielding member 40 was made of aluminum. The dimensions of the second shielding member 40 in the first direction D1 and the second direction D2 were 320 mm and 320 mm, respectively. The distance between the first shielding member 30 and the second shielding member 40 was 1 mm.

[0367] <Example 5-2> The coil unit 5 of Example 5-2 was fabricated in the same manner as in Example 5-1, except that the first shielding member 30 was divided into nine shielding pieces 30P as in the example shown in Fig. 20. The first shielding member 30 was divided into three in the first direction D1 and three in the second direction D2. Each shield piece 30P was a ferrite plate. All nine shield pieces 30P were rectangular. The dimensions of the nine shield pieces 30P in the first direction D1 were equal to each other. The dimensions of the nine shield pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Six of the twelve gaps 50 formed between adjacent shield pieces 30P crossed any of the first to third straight line portion groups 11G to 13G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13. Two of the twelve gaps 50 crossed multiple turn connections 16 . The remaining four gaps 50 extended between any of the first to fourth straight portion groups 11G to 14G and the central axis C when viewed in the axial direction.

[0368] <Example 5-3> The coil unit 5 of Example 5-3 was fabricated in the same manner as in Example 5-1, except that the first shielding member 30 was divided into 12 shielding pieces 30P. The first shielding member 30 was divided into three in the first direction D1 and into four in the second direction D2. Each shielding piece 30P was a ferrite plate. All twelve shielding pieces 30P were rectangular. The dimensions of the twelve shielding pieces 30P in the first direction D1 were equal to each other. The dimensions of the twelve shielding pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. One of the 17 gaps 50 formed between adjacent shield pieces 30P crossed the second straight portion group 12G when viewed in the axial direction. When viewed in the axial direction, the gap 50 crossing the second straight portion group 12G was perpendicular to the second straight portion 12. Twelve of the 17 gaps 50 crossed at least a portion of any of the 1A to 1D intermediate curved portions 151G to 154G when viewed in the axial direction. When viewed in the axial direction, the angle formed between the gap 50 crossing at least a portion of the 1A intermediate curved portion group 151G and a tangent line TL1 to the 1A intermediate curved portion group 151G was 45°. When viewed in the axial direction, the angle formed between the gap 50 crossing at least a portion of the 1B intermediate curved portion group 152G and a tangent line TL2 to the 1B intermediate curved portion group 152G was 45°. When viewed in the axial direction, the angle formed between the gap 50 crossing at least a portion of the 1C intermediate curved portion group 153G and a tangent line TL3 to the 1C intermediate curved portion group 153G was 45°. When viewed in the axial direction, the angle formed by the gap 50 that crosses at least a part of the first-dimensional intermediate curved portion group 154G and the tangent line TL4 of the first-dimensional intermediate curved portion group 154G was 45°. One of the 17 gaps 50 crossed a plurality of turn connection portions 16 when viewed in the axial direction. Two of the 17 gaps 50 extended along the first direction D1 within the first straight portion group 11G or the third straight portion group 13G when viewed in the axial direction. These gaps 50 overlapped with the first straight portion 11 or the third straight portion 13 of the second turn portion 102. The remaining gap 50 extended along the first direction D1 between the first straight portion group 11G and the third straight portion group 13G as viewed in the axial direction. This gap 50 overlapped with the central axis C as viewed in the axial direction.

[0369] <Example 5-4> 23, the coil unit 5 of Example 5-4 was fabricated in the same manner as in Example 5-1, except that the first shielding member 30 was formed by dividing it into eight shielding pieces 30P. The eight gaps 50 formed in the first shielding member 30 extended radially from the central axis C when viewed in the axial direction. Each shield piece 30P was a ferrite plate. All eight shield pieces 30P were right-angled triangles. The dimensions of the eight shield pieces 30P in the first direction D1 were equal to each other. The dimensions of the eight shield pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Of the eight gaps 50 formed between adjacent shield pieces 30P, three crossed any of the first to third straight line portion groups 11G to 13G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13. These four gaps 50 were formed so that their extensions passed through the central axis C. One of the eight gaps 50 crossed a plurality of turn connection portions 16 when viewed in the axial direction. This gap 50 was formed so that its extension line passed through the central axis C. The remaining four gaps crossed one of the 1A to 1D intermediate curve portion groups 151G to 154G when viewed in the axial direction. The gap 50 crossing the 1A intermediate curve portion group 151G was perpendicular to the tangent TL1 of the 1A intermediate curve portion group 151G when viewed in the axial direction. The gap 50 crossing the 1B intermediate curve portion group 152G was perpendicular to the tangent TL2 of the 1B intermediate curve portion group 152G when viewed in the axial direction. The gap 50 crossing the 1C intermediate curve portion group 153G was perpendicular to the tangent TL3 of the 1C intermediate curve portion group 153G when viewed in the axial direction. The gap 50 crossing the 1D intermediate curve portion group 154G was perpendicular to the tangent TL4 of the 1D intermediate curve portion group 154G when viewed in the axial direction. These four gaps 50 were formed so that their extensions passed through the central axis C.

[0370] <Example 5-5> As shown in FIG. 33, the coil unit 5 of Example 5-5 was fabricated in the same manner as in Example 5-1, except that the first shield member 30 was formed by dividing it into 12 shield pieces 30P. Each shield piece 30P was a ferrite plate. Four of the 12 shield pieces 30P were square. The remaining eight shield pieces 30P were right-angled triangles. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Six of the 13 gaps 50 formed between adjacent shield pieces 30P crossed any of the first to third straight line portion groups 11G to 13G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13. Two of the thirteen gaps 50 crossed a plurality of turn connection portions 16 when viewed in the axial direction. Four of the thirteen gaps 50 crossed at least a portion of the 1A to 1D intermediate curved portion groups 151G to 154G when viewed in the axial direction. The gap 50 crossing the 1A intermediate curved portion group 151G was perpendicular to the tangent TL1 of the 1A intermediate curved portion group 151G when viewed in the axial direction. The gap 50 crossing the 1B intermediate curved portion group 152G was perpendicular to the tangent TL2 of the 1B intermediate curved portion group 152G when viewed in the axial direction. The gap 50 crossing the 1C intermediate curved portion group 153G was perpendicular to the tangent TL3 of the 1C intermediate curved portion group 153G when viewed in the axial direction. The gap 50 crossing the 1D intermediate curved portion group 154G was perpendicular to the tangent TL4 of the 1D intermediate curved portion group 154G when viewed in the axial direction. The remaining gap 50, as viewed in the axial direction, extended along the second direction D2 between the second straight portion group 12G and the plurality of turn connection portions 16. This gap 50 overlapped with the central axis C, as viewed in the axial direction.

[0371] (Evaluation of Example 5) An 85 kHz high-frequency current was passed through the coil 10 of the coil units 5 of Examples 5-1 to 5-5 fabricated in this manner, and the Q value, loss, impedance, and inductance of the coil units 5 were measured. Figure 51 shows the measurement results. In Figure 51, "Q value," "impedance," and "inductance" refer to the Q value, impedance, and inductance of the coil unit 5. "SLD2" refers to the second shield member 40. "Joule loss" refers to the loss caused by the current in the coil 10 or the second shield member 40. "Iron loss" refers to the loss caused by the magnetic flux of the first shield member 30. "Total loss" is the sum of "Joule loss" and "Iron loss." "NP" refers to the number of divisions of the first shield member 30 (the number of shield pieces 30P included in the first shield member 30). For example, "NP9" means that the first shield member 30 is divided into nine pieces, and "NP12" means that the first shield member 30 is divided into twelve pieces. However, "NP1" means that the first shield member 30 is not divided.

[0372] <Example 6-1> The coil unit 5 of Example 6-1 was fabricated in the same manner as in Example 5-1, except that the coil elements 10j, 10jj were formed into a regular octagonal shape as a whole, as in the example shown in Fig. 45. The first shielding member 30 was not divided into a plurality of shielding pieces 30P. In other words, no gaps 50 were formed in the first shielding member 30. The coil 10 was made of copper and had a wire width of 6 mm and a thickness of 0.5 mm. The distance between adjacent turn portions 101, 102;...; 104, 105 was 6 mm. The dimensions of the coil 10 along the first direction D1 and the second direction D2 were 295 mm and 295 mm, respectively. The first shielding member 30 was a ferrite plate. The dimensions of the first shielding member 30 in the first direction D1 and the second direction D2 were 300 mm and 300 mm, respectively.

[0373] <Example 6-2> The coil unit 5 of Example 6-2 was fabricated in the same manner as in Example 6-1, except that the first shielding member 30 was divided into nine shielding pieces 30P in the same manner as in Example 5-2. The first shielding member 30 was divided into three in the first direction D1 and three in the second direction D2. Each shield piece 30P was a ferrite plate. All nine shield pieces 30P were rectangular. The dimensions of the nine shield pieces 30P in the first direction D1 were equal to each other. The dimensions of the nine shield pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. The 12 gaps 50 formed between adjacent shield pieces 30P crossed at least a portion of any of the first to third straight portion groups 11G to 13G and the 1A to 1D intermediate straight portion groups 161G to 164G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing at least a portion of the first straight portion group 11G were perpendicular to the first straight portion 11. When viewed in the axial direction, the gaps 50 crossing at least a portion of the second straight portion group 12G were perpendicular to the second straight portion 12. When viewed in the axial direction, the gaps 50 crossing at least a portion of the third straight portion group 13G were perpendicular to the third straight portion 13. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1A intermediate straight portion group 161G and the 1A intermediate straight portion group 161G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1B intermediate straight portion group 162G and the 1B intermediate straight portion group 162G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1C intermediate straight portion group 163G and the 1C intermediate straight portion group 163G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1D intermediate straight portion group 164G and the 1D intermediate straight portion group 164G was 45°.

[0374] <Example 6-3> The coil unit 5 of Example 6-3 was fabricated in the same manner as in Example 6-1, except that the first shielding member 30 was divided into 12 shielding pieces 30P of Example 5-3. The first shielding member 30 was divided into three parts in the first direction D1 and four parts in the second direction D2. Each shielding piece 30P was a ferrite plate. All twelve shielding pieces 30P were rectangular. The dimensions of the twelve shielding pieces 30P in the first direction D1 were equal to each other. The dimensions of the twelve shielding pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. One of the 17 gaps 50 formed between adjacent shield pieces 30P crossed the second straight portion group 12G when viewed in the axial direction. When viewed in the axial direction, the gap 50 crossing the second straight portion group 12G was perpendicular to the second straight portion 12. Twelve of the seventeen gaps 50 crossed at least a part of any of the first to third straight portion groups 11G to 13G and the 1A to 1D intermediate straight portion groups 161G to 164G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing at least a portion of the first straight portion group 11G were perpendicular to the first straight portion 11. When viewed in the axial direction, the gaps 50 crossing at least a portion of the second straight portion group 12G were perpendicular to the second straight portion 12. When viewed in the axial direction, the gaps 50 crossing at least a portion of the third straight portion group 13G were perpendicular to the third straight portion 13. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1A intermediate straight portion group 161G and the 1A intermediate straight portion group 161G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1B intermediate straight portion group 162G and the 1B intermediate straight portion group 162G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1C intermediate straight portion group 163G and the 1C intermediate straight portion group 163G was 45°. When viewed in the axial direction, the angle formed by the gap 50 crossing at least a portion of the 1D intermediate straight portion group 164G and the 1D intermediate straight portion group 164G was 45°. Two of the 12 gaps 50 extended along the first direction D1 within the first straight portion group 11G or the third straight portion group 13G when viewed in the axial direction. These gaps 50 overlapped with the first straight portion 11 or the third straight portion 13 of the second turn portion 102. One of the 17 gaps 50 crossed a plurality of turn connection portions 16 when viewed in the axial direction. The remaining gap 50 extended along the first direction D1 between the first straight portion group 11G and the third straight portion group 13G as viewed in the axial direction. This gap 50 overlapped with the central axis C as viewed in the axial direction.

[0375] <Example 6-4> The coil unit 5 of Example 6-4 was produced in the same manner as in Example 6-1, except that the first shielding member 30 was divided into eight shielding pieces 30P in the same manner as in Example 5-4. The eight gaps 50 formed in the first shielding member 30 extended radially from the central axis C when viewed in the axial direction. Each shield piece 30P was a ferrite plate. All eight shield pieces 30P were right-angled triangles. The dimensions of the eight shield pieces 30P in the first direction D1 were equal to each other. The dimensions of the eight shield pieces 30P in the second direction D2 were also equal to each other. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Three of the eight gaps 50 formed between adjacent shield pieces 30P cross any of the first to third straight line portion groups 11G to 13G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G are perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the second straight line portion group 12G are perpendicular to the second straight line portion 12. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G are perpendicular to the third straight line portion 13. One of the eight gaps 50 crossed a plurality of turn connection portions 16 when viewed in the axial direction. The remaining four gaps crossed one of the 1A to 1D intermediate straight portion groups 161G to 164G when viewed in the axial direction. When viewed in the axial direction, the gap 50 crossing the 1A intermediate straight portion group 161G was perpendicular to the 1A intermediate straight portion group 161G. When viewed in the axial direction, the gap 50 crossing the 1B intermediate straight portion group 162G was perpendicular to the 1B intermediate straight portion group 162G. When viewed in the axial direction, the gap 50 crossing the 1C intermediate straight portion group 163G was perpendicular to the 1C intermediate straight portion group 163G. When viewed in the axial direction, the gap 50 crossing the 1D intermediate straight portion group 164G was perpendicular to the 1D intermediate straight portion group 164G.

[0376] <Example 6-5> The coil unit 5 of Example 6-5 was fabricated in the same manner as in Example 6-1, except that the first shield member 30 was divided into 12 shield pieces 30P in the same manner as in Example 5-5. Each shield piece 30P was a ferrite plate. Four of the 12 shield pieces 30P were square. The remaining eight shield pieces 30P were right-angled triangles. The width of the gap 50 between adjacent shield pieces 30P was 5 mm. Six of the 13 gaps 50 formed between adjacent shield pieces 30P crossed any of the first to third straight line portion groups 11G to 13G when viewed in the axial direction. When viewed in the axial direction, the gaps 50 crossing the first straight line portion group 11G were perpendicular to the first straight line portion 11. When viewed in the axial direction, the gaps 50 crossing the second straight line portion group 12G were perpendicular to the second straight line portion 12. When viewed in the axial direction, the gaps 50 crossing the third straight line portion group 13G were perpendicular to the third straight line portion 13. Two of the thirteen gaps 50 crossed a plurality of turn connection portions 16 when viewed in the axial direction. Four of the thirteen gaps 50 crossed any of the 1A to 1D intermediate straight portion groups 161G to 164G when viewed in the axial direction. The gaps 50 crossing the 1A intermediate straight portion group 161G were perpendicular to the 1A intermediate straight portion group 161G when viewed in the axial direction. The gaps 50 crossing the 1B intermediate straight portion group 162G were perpendicular to the 1B intermediate straight portion group 162G when viewed in the axial direction. The gaps 50 crossing the 1C intermediate straight portion group 163G were perpendicular to the 1C intermediate straight portion group 163G when viewed in the axial direction. The gaps 50 crossing the 1D intermediate straight portion group 164G were perpendicular to the 1D intermediate straight portion group 164G when viewed in the axial direction. The remaining gap 50 extended along the first direction D1 between the first straight portion group 11G and the third straight portion group 13G as viewed in the axial direction. This gap 50 overlapped with the central axis C as viewed in the axial direction.

[0377] (Evaluation of Example 6) An 85 kHz high-frequency current was passed through the coil 10 of the coil unit 5 of Examples 6-1 to 6-5 fabricated in this manner, and the Q value, loss, impedance, and inductance of the coil unit 5 were measured. The measurement results are shown in FIG. 52. In FIG. 52, "Q value," "impedance," and "inductance" refer to the Q value, impedance, and inductance of the coil unit 5. "SLD2" refers to the second shield member 40. "Joule loss" refers to the loss caused by the current in the coil 10 or the second shield member 40. "Iron loss" refers to the loss caused by the magnetic flux of the first shield member 30. "Total loss" is the sum of "Joule loss" and "Iron loss." "NP" refers to the number of divisions of the first shield member 30 (the number of shield pieces 30P included in the first shield member 30). For example, "NP9" means that the first shield member 30 is divided into nine pieces, and "NP12" means that the first shield member 30 is divided into twelve pieces. However, "NP1" means that the first shield member 30 is not divided.

[0378] (Comparison of Example 5 and Example 6) FIG. 53 shows the Q values of the coil units 5 of Examples 5-1 to 5-5 and Examples 6-1 to 6-5. In FIG. 53, E5-1 to E5-5 represent Examples 5-1 to 5-5, respectively. Also, in FIG. 53, E6-1 to E6-5 represent Examples 6-1 to 6-5, respectively. It can be seen from FIG. 53 that, other conditions being the same, the Q value of a coil unit 5 including a coil 10 that is octagonal as a whole is higher than the Q value of a coil unit 5 including a coil 10 that is rectangular as a whole and includes first intermediate curved portions 151G to 154G.

[0379] <<Example 7>> Next, the difference in performance of the coil unit 5 between when the coil 10 is plate-shaped and when it is a litz wire coil will be described.

[0380] <Example 7-1> Coil unit 5 of Example 7-1 was fabricated in the same manner as in Example 3-2. The distance between first shield member 30 and second shield member 40 was 1 mm, the same as in Example 3-2. <Example 7-2> Coil unit 5 of Example 7-2 was fabricated in the same manner as in Example 7-1, except that the distance between first shield member 30 and second shield member 40 was set to 10 mm. <Example 7-3> Coil unit 5 of Example 7-3 was fabricated in the same manner as in Example 3-5. The distance between first shield member 30 and second shield member 40 was 1 mm, the same as in Example 7-1. <Example 7-4> Coil unit 5 of Example 7-4 was fabricated in the same manner as in Example 7-3, except that the distance between first shield member 30 and second shield member 40 was set to 10 mm. <Comparative Example 7-1> The coil unit 5 of Comparative Example 7-1 was fabricated in the same manner as in Example 7-1, except that the coil 10 was formed from a litz wire. The litz wire used was made by twisting together 1,600 enameled wires with a diameter of 0.05 mm. The coil 10 consisted of a single coil element having eight turn portions 101 to 108. The thickness (diameter) of the litz wire was 3.0 mm. The distance between adjacent turn portions 101, 102; 107, 108 was 6 mm. The dimensions of the coil 10 along the first direction D1 and the second direction D2 were 295 mm and 295 mm, respectively. The magnetic substance resin layer 20 was in direct contact with the litz wire. However, because the litz wire is made of an enameled wire, the magnetic substance resin layer 20 was not in direct contact with the conductor of the litz wire. The distance between the first shielding member 30 and the second shielding member 40 was 1 mm, as in Example 7-1. When viewed in the axial direction, the shape and dimensions of the contour of the coil 10 of Comparative Example 7-1 were approximately the same as the contour of the coil 10 of Example 7-1. <Comparative Example 7-2> Coil unit 5 of Comparative Example 7-2 was produced in the same manner as in Comparative Example 7-1, except that the distance between first shield member 30 and second shield member 40 was set to 10 mm. <Comparative Example 7-3> The coil unit 5 of Comparative Example 7-3 was produced in the same manner as in Example 7-3, except that the coil 10 was formed from a litz wire. The coil 10 was produced in the same manner as the coil 10 of Comparative Example 7-1. The distance between the first shielding member 30 and the second shielding member 40 was 1 mm, as in Example 7-1. <Comparative Example 7-4> Coil unit 5 of Comparative Example 7-4 was produced in the same manner as in Comparative Example 7-3, except that the distance between first shield member 30 and second shield member 40 was set to 10 mm.

[0381] (evaluation) A high-frequency current of 85 kHz was passed through the coil 10 of the coil unit 5 of Examples 7-1 to 7-4 and Comparative Examples 7-1 to...

Claims

[Claim 1] a coil including a coil element formed in a spiral shape around a central axis, a magnetic resin layer, a first shielding member, and a second shielding member; the coil has a first main surface and a second main surface that is a surface opposite to the first main surface, the magnetic resin layer is in direct contact with the second main surface of the coil, the coil and the magnetic resin layer, the first shielding member, and the second shielding member are laminated in this order in a direction from the first main surface toward the second main surface, The first shield member is divided into a plurality of small shield pieces.

Images