Coil component, power transmitting device, power receiving device, and power transmission system

Abstract

To provide a coil component in which the decrease of coil performance due to an influence of a member around a coil can be suppressed.SOLUTION: A coil component 10A includes a coil 11 and a case 20 with a side wall part 23 existing at an outer periphery of the coil 11. The side wall part 23 includes two kinds of materials. One material of the two kinds of materials is conductive and the other material is magnetic. The one material may be metal and the other material may be ferrite.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In recent years, wireless power transmission systems that transmit power contactlessly have become widespread. Demand for wireless power transmission systems that can transmit large amounts of power is expected to increase in the future.

[0003] When transmitting large amounts of power wirelessly, 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] The skin effect increases AC resistance and consumes power due to heat generation, which can also cause a decrease in transmission efficiency.

[0005] When litz wire is used as a coil, the skin effect is suppressed. However, since litz wire is formed by twisting together a large number of enameled wires, manufacturing costs are high and manufacturing is time-consuming. On the other hand, a technique using a spiral, plate-shaped planar coil is also known (see Patent Document 1). Such a planar coil improves manufacturing efficiency regardless of the coil size. Therefore, planar coils are suitable for high-power systems where the coil size can be large. Note that a planar coil can also be created by winding litz wire in a spiral shape, but this does not improve manufacturing efficiency.

[0006] In a wireless power transmission system for an electric vehicle, a power transmitter is installed on the road surface, such as a parking lot, and a power receiver is installed in the electric vehicle. For example, when a planar coil is used in an electric vehicle, the height dimensions of both the power transmitter and the power receiver can be reduced. Therefore, planar coils are useful in applications where strict space constraints are imposed, such as the automotive field. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-27112 Summary of the Invention [Problem to be solved by the invention]

[0008] When a planar coil is used in a power transmitting device and a power receiving device as described above, the planar coil is incorporated inside each device. When the power transmitting device is installed on the road surface, it is expected that a vehicle will run over the power transmitting device. Therefore, it is desirable to support the upper wall portion that protects the planar coil with side walls extending downward from the upper wall portion or with supports placed inside the device.

[0009] The sidewalls and support pillars described above may be made of metal. In this case, it is easier to ensure the desired strength. However, because metal sidewalls and support pillars are conductive, there is a risk that they may undesirably affect the transmission characteristics of the coil due to, for example, the generation of eddy currents. Furthermore, many metal peripheral parts are located around the power receiving device installed in the vehicle. These metal peripheral parts may also undesirably affect the transmission characteristics of the coil.

[0010] The present disclosure has been made in consideration of the above circumstances, and its objective is to provide a coil component, a power transmitting device, a power receiving device, and a power transfer system that can prevent the performance of a coil from being reduced due to the influence of components surrounding the coil. [Means for solving the problem]

[0011] A coil component according to one embodiment comprises a coil and a case having a side wall portion located on the outer periphery of the coil, the side wall portion including two types of materials, one of which is conductive and the other of which is magnetic or insulating.

[0012] The one material may be a metal, the other material may be magnetic, and the other material may have a higher magnetic permeability than the one material and a higher electrical resistance than the one material.

[0013] The other material may include any one or more of ferrite, silicon steel, soft magnetic iron, and amorphous metal.

[0014] The other material may include particles of one or more of ferrite, silicon steel, soft magnetic iron, and amorphous metal, and a resin containing the particles.

[0015] Furthermore, the one material may be a metal and the other material may be a resin.

[0016] The other material may form a portion including an end of the side wall portion on one side of the coil in the axial direction, and the one material may form a portion of the side wall portion different from the portion including the end.

[0017] Moreover, a coil component according to one embodiment includes a coil and a case having a side wall portion located on the outer periphery of the coil, the side wall portion including two types of materials, one of which is resin and the other of which is magnetic.

[0018] The other material may form an inner circumferential surface of the side wall portion facing the coil.

[0019] In addition, a coil component according to one embodiment may further include a support pillar extending in the axial direction of the coil, the support pillar including two types of materials, one of which, a first support pillar material, is conductive, and the other of which, a second support pillar material, is magnetic or insulating.

[0020] The second strut material may form a portion of the strut that includes an end of the strut on one axial side of the coil, and the first strut material may form a portion of the strut that is different from the portion that includes the end.

[0021] The second strut material may form an outer periphery of the strut, and the portion of the strut formed by the first strut material may be at least partially covered by the second strut material.

[0022] Moreover, the coil component according to one embodiment may further include a magnetic shield member arranged to overlap the coil when viewed in the axial direction of the coil.

[0023] The magnetic shield member may include ferrite.

[0024] Moreover, a power transmitting device according to one embodiment includes the coil component. A power receiving device according to one embodiment includes the coil component. Moreover, a power transfer system according to one embodiment includes a power transmitting device and a power receiving device, and at least one of the power transmitting device and the power receiving device includes the coil component. [Effects of the Invention]

[0025] According to the present disclosure, it is possible to prevent the performance of the coil from being reduced due to the influence of members surrounding the coil. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a diagram schematically illustrating a wireless power transmission system to which a coil component according to an embodiment can be applied. [Figure 2] FIG. 1 is a perspective view of a coil component according to a first embodiment. [Figure 3] FIG. 3 is a cross-sectional view of the coil component taken along line III-III in FIG. 2. [Figure 4] 1 is a perspective view of the periphery of a support pillar included in a coil component according to a first embodiment. [Figure 5] FIG. 10 is a perspective view of a coil component according to a second embodiment, showing the periphery of a support pillar provided in the coil component. [Figure 6]FIG. 10 is a cross-sectional view of a coil component according to a second embodiment. [Figure 7] FIG. 10 is a cross-sectional view of a coil component according to a third embodiment. [Figure 8] FIG. 10 is a perspective view of a coil component according to a fourth embodiment. [Figure 9] FIG. 10 is a perspective view of a central support provided in a coil device according to a fourth embodiment. [Figure 10] 9 is a cross-sectional view of the coil component taken along line XX in FIG. 8. [Figure 11] FIG. 10 is a perspective view of a coil component according to a fifth embodiment. [Figure 12] FIG. 13 is a perspective view of a coil component according to a sixth embodiment. [Figure 13] FIG. 13 is a perspective view of a coil component according to a seventh embodiment, in which a part of the coil component is cut away. [Figure 14] FIG. 13 is a cross-sectional view of a coil component according to a seventh embodiment. [Figure 15] FIG. 13 is a perspective view of a coil and a case included in a coil component according to a seventh embodiment. [Figure 16] FIG. 16 is an exploded view of the coil and case shown in FIG. [Figure 17] FIG. 13 is a graph showing a simulation result regarding performance evaluation (inductance) of the coil component according to the seventh embodiment. [Figure 18] FIG. 13 is a graph showing a simulation result regarding performance evaluation (case loss) of the coil component according to the seventh embodiment. [Figure 19] FIG. 13 is a graph showing a simulation result regarding performance evaluation (coil loss) of the coil component according to the seventh embodiment. [Figure 20] FIG. 13 is a plan view of a coil component according to an eighth embodiment. [Figure 21] FIG. 13 is a perspective view of a coil component according to an eighth embodiment. [Figure 22] FIG. 13 is a side view of a coil device according to an eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] Each embodiment will be described below with reference to the drawings.

[0028] In this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely based on the difference in name. Therefore, for example, "sheet" is a concept that also includes members that can be called films or plates.

[0029] In addition, in this specification, "sheet surface (plate surface, film surface)" refers to a surface that coincides with the planar direction (face direction) of the target sheet-like component when viewed overall and from a global perspective.

[0030] <Wireless power transmission system> 1 schematically shows a wireless power transmission system S to which coil components according to embodiments described below can be applied. First, the wireless power transmission system S (hereinafter abbreviated as power transmission system S) will be described with reference to FIG.

[0031] 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 component 10 and a high-frequency current supply unit 1A. The coil component 10 in the power transmitting device 1 functions as a power transmitting coil. The high-frequency current supply unit 1A supplies a high-frequency current to the coil component 10 serving as a power transmitting coil.

[0032] The power receiving device 2 includes a coil component 10 and a conversion unit 2A. The coil component 10 in the power receiving device 2 functions as a power receiving coil. The conversion unit 2A shapes the high-frequency current generated in the coil component 10. The conversion unit 2A includes a rectifier circuit that converts the high-frequency current into a direct current.

[0033] When transmitting power wirelessly (contactlessly) from the power transmitting device 1 to the power receiving device 2, the power transmitting device 1 supplies a high-frequency current of a predetermined frequency from the high-frequency current supply unit 1A to the coil component 10 serving as a power transmitting coil. At this time, a magnetic field is generated in the coil component 10 due to electromagnetic induction. Then, due to the influence of this magnetic field, a high-frequency current is generated in the coil component 10 serving as a power receiving coil 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).

[0034] 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 be configured as a power transmission system using an electromagnetic induction method. The power transmission system S is also 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.

[0035] However, the use of the power transmission system S is not limited to power transmission to electric vehicles. For example, the power transmission system S may be used to transmit power to flying objects such as drones and robots. The power transmission system S may also be used to transmit power to underwater submersibles and exploration robots. The use of the coil components according to the embodiments is not limited to wireless power transmission systems. For example, the coil components according to the embodiments may be used in transformers, DC-DC converters, antennas, etc.

[0036] Each power transmission system S includes, as the coil component 10, one of the coil components according to each embodiment described below. The same embodiment of the coil component may be used in each of the power transmitting device 1 and the power receiving device 2. Alternatively, different embodiments of the coil component may be used in each of the power transmitting device 1 and the power receiving device 2. Alternatively, a coil component according to an embodiment may be used in one of the power transmitting device 1 and the power receiving device 2, and a coil component of another type may be used in the other. The coil components according to each embodiment will be described below.

[0037] First Embodiment Fig. 2 is a perspective view of a coil device 10A according to the first embodiment. Fig. 3 is a cross-sectional view of the coil device 10A taken along line III-III in Fig. 2. Fig. 4 is a perspective view of the periphery of a support 24 provided in the coil device 10A. Specifically, Fig. 3 is a cross-sectional view of the coil device 10A cut in the direction of the arrow extending from line III-III.

[0038] 2 to 4, the coil device 10A includes a coil 11, a case 20, a magnetic shield member 40, a first connection terminal 51, and a second connection terminal 52. The case 20 includes a bottom wall portion 22 and a side wall portion 23 rising from the bottom wall portion 22. The magnetic shield member 40 and the coil 11 are arranged in this order on the bottom wall portion 22. The magnetic shield member 40 and the coil 11 are also surrounded by the side wall portion 23.

[0039] Coil 11 has a spiral shape and is made of a conductive material. In this embodiment, coil 11 is made of copper, but coil 11 may be made of any conductive material, such as aluminum. Coil 11 is also plate-shaped. As shown in FIG. 3, the cross section of coil 11 in a direction perpendicular to the winding direction of the spiral shape is rectangular.

[0040] The symbol C in Figures 2 and 3 indicates the central axis of the coil 11, which passes through the center of the spiral shape of the coil 11. Hereinafter, the axial direction of the coil 11 refers to a direction extending on the central axis C or a direction parallel to the central axis C. The direction perpendicular to the central axis C is referred to as the radial direction. As shown in Figure 2, the coil 11 is wound so that multiple winding portions (circumferential portions) arranged in the radial direction that form the spiral shape form a rectangular shape. However, the coil 11 may also be wound so that each winding portion (circumferential portion) forms a circle. The spiral shape refers to a planar curve shape wound in a spiral shape. The planar curve referred to here also includes a planar pattern that is bent like a broken line, as shown in the figure. In other words, the spiral shape is a shape that winds around the central axis C of the coil 11 so that it is positioned gradually outward.

[0041] In this embodiment, coil 11 is formed by punching out a copper plate into a spiral shape. The thickness of coil 11 may be, for example, 0.2 mm or more and 1.0 mm or less. Furthermore, the radius of coil 11 (the distance from the central axis C to the radially furthest point) may be 200 mm or more. When transmitting power to an electric vehicle using the magnetic resonance method, it is desirable to be able to transmit 1 kW or more, and 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 coil 11 made of copper is preferably 0.4 mm or more. Note that if coil 11 is too thick, it will increase its weight and is not suitable for in-vehicle use. Therefore, the thickness of coil 11 may be, for example, 1.0 mm or less.

[0042] Alternatively, the coil 11 can be formed by etching copper foil into a spiral shape. In this case, the coil 11 can be formed into a complex spiral pattern. However, it takes time and effort to ensure that the coil 11 is thick enough to transmit high power. Therefore, punching is preferable from the viewpoint of manufacturing efficiency.

[0043] The case 20 supports the coil 11 and the magnetic shield member 40 on the bottom wall portion 22 while being spaced apart in the axial direction of the coil 11. That is, the coil 11 and the magnetic shield member 40 are spaced apart from the coil 11 in the axial direction of the coil 11. The coil 11 and the magnetic shield member 40 may be supported on the bottom wall portion 22 via a plurality of coil supports provided between the bottom wall portion 22 and the magnetic shield member 40. Alternatively, the coil 11 and the magnetic shield member 40 may be supported on the bottom wall portion 22 via a plate member provided between the bottom wall portion 22 and the magnetic shield member 40.

[0044] The side wall portion 23 is located on the outer periphery of the coil 11, and in this example, surrounds the entire circumference of the coil 11. The end of the side wall portion 23 opposite the bottom wall portion 22 is open. In other words, the case 20 has a shape with one end open. Furthermore, the bottom wall portion 22 and the side wall portion 23 are rectangular in plan view, but may be other shapes such as circular.

[0045] Case 20 in this embodiment further includes support pillars 24 at the four corners of bottom wall 22, and each support pillar 24 extends in the axial direction of coil 11. Support pillar 24 extends from bottom wall 22 side to cross side wall 23 in the axial direction of coil 11. As shown in FIG. 3 , the end of support pillar 24 opposite bottom wall 22 side contacts covering wall 25 indicated by a two-dot chain line, thereby supporting covering wall 25. Support pillar 24 has a cylindrical shape, but the shape is not particularly limited.

[0046] Coil device 10A may be incorporated into, for example, a power transmission device installed on the road surface. In this case, covering wall portion 25 protects coil 11 by covering it from above. In a power transmission device installed on the road surface, it is expected that a vehicle will run over the power transmission device. In this case, the load of the vehicle received by covering wall portion 25 is transmitted to support pillar 24. Note that a further support pillar may be provided on the central axis C side of support pillar 24, passing through coil 11 in the axial direction, and covering wall portion 25 may be additionally supported by such a support pillar.

[0047] The covering wall portion 25 preferably has high rigidity and strength and is preferably non-conductive. In consideration of these points, the material of the covering wall portion 25 may be fiber-reinforced plastic. However, the material of the covering wall portion 25 is not particularly limited.

[0048] The bottom wall portion 22 is made of a metal material and is conductive. Specifically, the bottom wall portion 22 in this embodiment is made of aluminum. As described above, it is assumed that the coil device 10A will be incorporated into a power transmission device that is installed on the road surface. In this case, it is desirable that the bottom wall portion 22 has high rigidity and strength. Therefore, a metal is used as the material for the bottom wall portion 22. The material for the bottom wall portion 22 is not particularly limited, and may be an aluminum alloy, stainless steel, or the like.

[0049] The sidewall 23 includes two materials, one of which is conductive and the other of which is magnetic. Specifically, the sidewall 23 includes a metal and a material that has a higher magnetic permeability and a higher electrical resistance than the metal. Specifically, the sidewall 23 in this embodiment includes aluminum and ferrite.

[0050] 3 and 4, the side wall 23 has a tip portion 23A including an end portion on one side (upper side in FIG. 3) in the axial direction of the coil 11, and a base portion 23B which is the remaining portion located between the tip portion 23A and the bottom wall 22. The tip portion 23A is made of ferrite, and the base portion 23B is made of aluminum.

[0051] In this embodiment, distal portion 23A is formed of ferrite, but is not limited thereto and may be formed of silicon steel, soft electromagnetic iron, or amorphous metal. Furthermore, distal portion 23A may be formed of a material containing two or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal. Furthermore, distal portion 23A may be formed of a material containing a plurality of particles of one or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal, and a resin containing the plurality of particles.

[0052] On the other hand, the base end portion 23B may be made of an aluminum alloy, stainless steel, etc. The base end portion 23B may be formed integrally with the bottom wall portion 22. Alternatively, the base end portion 23B and the bottom wall portion 22 may be formed separately, and then the base end portion 23B may be joined to the bottom wall portion 22.

[0053] Similarly to the sidewall 23, the support 24 also contains two materials, one of which, a first support material, is conductive and the other, a second support material, is magnetic. Specifically, the support 24 also contains a metal and a material that has a higher magnetic permeability and a higher electrical resistance than the metal. Specifically, the support 24 also contains aluminum and ferrite.

[0054] 3 and 4, the support 24 has a tip-side column portion 24A that includes an end portion on one side (upper side in FIG. 3) in the axial direction of the coil 11, and a base-side column portion 24B that is the remaining portion located between the tip-side column portion 24A and the bottom wall portion 22. The tip-side column portion 24A is made of ferrite, and the base-side column portion 24B is made of aluminum.

[0055] As with the side wall portion 23, the tip column portion 24A is formed of ferrite, but is not limited to this and may be formed of silicon steel, soft electromagnetic iron, or amorphous metal. The tip column portion 24A may also be formed of a material containing two or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal. The tip column portion 24A may also be formed of a material containing a plurality of particles made of one or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal, and a resin containing the plurality of particles.

[0056] On the other hand, the base-side pillar portion 24B may be made of an aluminum alloy, stainless steel, etc. The base-side pillar portion 24B may be formed integrally with the bottom wall portion 22. Alternatively, the base-side pillar portion 24B and the bottom wall portion 22 may be formed separately, and then the base-side pillar portion 24B may be joined to the bottom wall portion 22.

[0057] The magnetic shield member 40 is provided to suppress the transmission of magnetic field lines and / or leakage magnetic fields. The magnetic shield member 40 is sheet-shaped and sized to encompass the coil 11 in a plan view. The magnetic shield member 40 is arranged to overlap the coil 11 when viewed in the axial direction of the coil 11. In this embodiment, the magnetic shield member 40 is in axial contact with the entire coil 11. In this embodiment, the magnetic shield member 40 includes a magnetic material. The magnetic field generated by the coil component 10A spreads in all directions relative to the central axis C of the coil 11. In this case, the magnetic shield member 40 has magnetism, which allows the spreading magnetic flux lines to be directed toward the central axis C. Furthermore, the coil component 10A may be installed in a vehicle. In this case, if the magnetic field generated by the coil component 10A flows toward other vehicle components, adverse effects may occur on the vehicle components. Therefore, the magnetic shield member 40 is provided to suppress the transmission of magnetic field lines. As a result, the magnetic shield member 40 can suppress leakage magnetic fields that do not contribute to the generation of current.

[0058] 2 and 3, the magnetic shield member 40 is in the form of a rectangular sheet, with the four corners of the magnetic shield member 40 chamfered. Through these chamfered portions, the support pillars 24 extend beyond the magnetic shield member 40 toward the coil 11. In addition, in this embodiment, the tip portion 23A of the side wall portion 23 is positioned so as to overlap the coil 11 and the magnetic shield member 40 in the radial direction of the coil 11 when viewed in the radial direction of the coil 11. Similarly, the tip pillar portion 24A of the support pillar 24 is positioned so as to overlap the coil 11 and the magnetic shield member 40 in the radial direction of the coil 11 when viewed in the radial direction of the coil 11.

[0059] The magnetic shield member 40 preferably includes a soft magnetic material. More specifically, the magnetic shield member 40 includes ferrite, preferably soft ferrite. The magnetic shield member 40 may be configured with a material that actively generates eddy currents to suppress the penetration of magnetic lines of force. In this case, the magnetic shield member 40 may be formed from a non-magnetic and conductive material, such as copper or aluminum. However, actively generating eddy currents can cause heat generation problems. Therefore, the use of ferrite is desirable, at least when the coil device 10A is installed in a vehicle.

[0060] As shown in Fig. 2, the first connection terminal 51 is connected to the inner peripheral end 11A of the coil 11. The second connection terminal 52 is connected to the outer peripheral end 11B of the coil 11. The first connection terminal 51 and the second connection terminal 52 can be used, for example, when connecting to the high-frequency current supply unit 1A or the conversion unit 2A. The connection between the first connection terminal 51 and the inner peripheral end 11A and the connection between the second connection terminal 52 and the outer peripheral end 11B are performed by ultrasonic bonding. However, the connection method is not limited thereto, and for example, a conductive adhesive may be used for connection.

[0061] (Coil component applications) The coil device 10A according to this embodiment can be used as a power transmitting coil in the power transmitting device 1 of the wireless power transmission system S described above, and as a power receiving coil in the power receiving device 2, for example.

[0062] When the coil component 10A is used as a power transmission coil, the first connection terminal 51 and the second connection terminal 52 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 component 10A, the current can flow from the first connection terminal 51 to the coil 11, and then from the second connection terminal 52 to the high-frequency current supply unit 1A or AC power supply. Alternatively, the current can flow from the second connection terminal 52 to the coil 11, and then from the first connection terminal 51 to the high-frequency current supply unit 1A or AC power supply. This allows a magnetic field including magnetic field lines along the central axis of the coil 11 to be generated.

[0063] On the other hand, when the coil device 10A is used as a receiving coil, a high-frequency current can be generated in the coil 11 by receiving a magnetic field including magnetic lines of force along the central axis of the coil 11. Then, this high-frequency current can be supplied to an external device from the first connection terminal 51 or the second connection terminal 52.

[0064] The coil component 10A can also be used in a transformer, an antenna, etc. For example, when the coil component 10A functions as a primary coil of a transformer, the first connection terminal 51 and the second connection terminal 52 are connected to an AC power source. When a high-frequency current is supplied, magnetic flux can be supplied from the center of the coil 11 to the iron core.

[0065] When a high-frequency current is supplied to the coil device 10A in the various applications described above to generate a magnetic field in the coil device 10A, the magnetic field periodically changes direction. Such a magnetic field can generate eddy currents when it attempts to intersect with metal. Examples of locations where such eddy currents can occur include the metal parts of the case 20 and other metal members located around the coil device 10A.

[0066] Therefore, in this embodiment, the sidewall portion 23 includes two materials, one of which is conductive and the other of which is magnetic. Specifically, the sidewall portion 23 includes a metal and a material having a higher magnetic permeability and a higher electrical resistance than the metal. Specifically, the sidewall portion 23 in this embodiment includes aluminum and ferrite. In this case, the generation of eddy currents is suppressed in the portion of the sidewall portion 23 formed of a material having a high magnetic permeability and a high electrical resistance, specifically ferrite. Therefore, inductance can be improved and loss can be reduced compared to when the entire sidewall portion 23 is formed of a conductive material with a relatively low electrical resistance, such as aluminum.

[0067] Similarly to the sidewall 23, the support 24 also contains two materials, one of which, a first support material, is conductive, and the other, a second support material, is magnetic. Specifically, the support 24 also contains a metal and a material that has a higher magnetic permeability and a higher electrical resistance than the metal. Specifically, the support 24 also contains aluminum and ferrite. In this case, inductance can be improved and loss can be reduced compared to when the entire support 24 is made of a conductive material with a relatively low electrical resistance, such as aluminum.

[0068] Therefore, coil device 10A according to the present embodiment can prevent the performance of coil 11 from being affected by the members around coil 11. Specifically, it is possible to prevent a situation in which inductance is significantly reduced and loss is significantly increased due to the influence of side wall portion 23, support pillar 24, and other surrounding metal members around coil 11, and therefore it is possible to prevent the performance of coil 11 from being affected by the members around coil 11.

[0069] In this embodiment, the tip portion 23A of the side wall portion 23 is made of ferrite, and the base portion 23B is made of aluminum. Also, the tip portion 24A of the support 24 is made of ferrite, and the base portion 24B is made of aluminum. In this case, the side wall portion 23 and the support 24 including two types of materials can be easily manufactured.

[0070] Furthermore, in this embodiment, the tip-side portion 23A of the side wall portion 23 is positioned so as to overlap the coil 11 and the magnetic shielding member 40 in the radial direction when viewed in the radial direction of the coil 11. Similarly, the tip-side column portion 24A of the support 24 is positioned so as to overlap the coil 11 and the magnetic shielding member 40 in the radial direction when viewed in the radial direction of the coil 11. In this case, the distance between the coil 11 and the base-side column portion 23B of the side wall portion 23 and the base-side column portion 24B of the support 24, which are conductive, is increased. Furthermore, the narrowing of the magnetic field path suppresses leakage magnetic flux. This effectively prevents a decrease in the performance of the coil 11.

[0071] In this embodiment, the side wall 23 and the support 24 each contain two types of material, one of which is conductive and the other of which is magnetic. Alternatively, only one of the side wall 23 and the support 24 may contain two types of material, one of which is conductive and the other of which is magnetic, and the other of the side wall 23 and the support 24 may be made of, for example, only a conductive metal material.

[0072] In this embodiment, the tip portion 23A of the side wall portion 23 is made of ferrite, and the base portion 23B is made of aluminum. The tip column portion 24A of the support column 24 is made of ferrite, and the base column portion 24B is made of aluminum. Alternatively, the distal portion 23A of the side wall 23 may be formed of an insulating material such as resin, and the proximal portion 23B may be formed of a conductive metal such as aluminum. Alternatively, the distal column portion 24A of the support 24 may be formed of an insulating material such as resin, and the proximal column portion 24B may be formed of a conductive metal such as aluminum.

[0073] Even with this configuration, no eddy currents are generated in the tip portion 23A of the side wall portion 23 and the tip column portion 24A of the support column 24. This reduces loss compared to when the side wall portion 23 and the support column 24 are entirely made of a conductive material with a relatively low electrical resistance, such as aluminum. This prevents the performance of the coil 11 from deteriorating.

[0074] <Second embodiment> Next, a coil device 10B according to a second embodiment will be described. Fig. 5 is a perspective view of the coil device 10B, specifically a perspective view of the periphery of a support 24 provided in the coil device 10B. Fig. 6 is a cross-sectional view of the coil device 10B corresponding to line III-III in Fig. 2. Components in this embodiment that are the same as those in the first embodiment are designated by the same reference numerals, and redundant description will be omitted.

[0075] 5 and 6, the support pillar 24 in this embodiment has a core portion 24C and an outer peripheral covering portion 24D. The core portion 24C rises from the bottom wall portion 22. The outer peripheral covering portion 24D covers the outer peripheral surface of the core portion 24C and forms the outer peripheral surface of the support pillar 24. As in the first embodiment, the support pillar 24 includes two types of materials, one of which, a first support pillar material, is conductive, and the other, a second support pillar material, is magnetic.

[0076] The magnetic second pillar material forms the outer covering portion 24D, which forms the outer peripheral surface of the pillar 24. On the other hand, the conductive first pillar material forms the core portion 24C. The entire outer peripheral surface of the core portion 24C is covered by the outer covering portion 24D.

[0077] In this embodiment, the outer coating portion 24D is made of ferrite, and the core portion 24C is made of aluminum. However, these materials are not particularly limited. The outer coating portion 24D may be made of silicon steel, soft electromagnetic iron, or amorphous metal. The outer coating portion 24D may also be made of a material containing two or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal. The outer coating portion 24D may also be made of a material containing a plurality of particles made of one or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal, and a resin containing the plurality of particles.

[0078] In this embodiment, the inductance of coil 11 can be improved and loss can be reduced compared to when all of support pillars 24 are made of a conductive material with a relatively low electrical resistance, such as aluminum. This prevents the performance of coil 11 from being affected by the components surrounding coil 11. Furthermore, core portion 24C contacts covering wall portion 25 and transmits the load received from covering wall portion 25 to bottom wall portion 22, which is advantageous in terms of durability.

[0079] <Third embodiment> Next, a coil device 10C according to a third embodiment will be described. Fig. 7 is a cross-sectional view of the coil device 10C taken along line III-III in Fig. 2. Components in this embodiment that are the same as those in the first and second embodiments are designated by the same reference numerals, and redundant description will be omitted.

[0080] In this embodiment, similar to the second embodiment, the support 24 has a core 24C and an outer circumferential covering 24D. However, only the tip-side portion of the outer circumferential surface of the core 24C is covered by the outer circumferential covering 24D. The core 24C tapers from the midpoint between the base end and the tip to the tip. The outer circumferential covering 24D is provided on this tapered portion of the core 24C. When viewed in the radial direction of the coil 11, the outer circumferential covering 24D is positioned so as to overlap the coil 11 and the magnetic shield member 40 in the radial direction of the coil 11.

[0081] In this embodiment, the inductance of coil 11 can be improved and loss can be reduced compared to when all of support pillars 24 are made of a conductive material with a relatively low electrical resistance, such as aluminum. This prevents the performance of coil 11 from being affected by the components surrounding coil 11. Furthermore, a large cross-sectional area of ​​core portion 24C can be ensured, which is even more advantageous in terms of durability.

[0082] <Fourth embodiment> Next, a coil device 10D according to a fourth embodiment will be described. FIG. 8 is a perspective view of the coil device 10D. FIG. 9 is a perspective view of a central support 26 included in the coil device 10D. FIG. 10 is a cross-sectional view of the coil device 10D taken along line XX in FIG. 8. Components in this embodiment that are the same as those in the first to third embodiments are designated by the same reference numerals, and redundant description will be omitted. More specifically, FIG. 10 is a cross-sectional view of the coil device 10D taken in the thickness direction at a position including line XX in FIG. 8, as viewed in the direction of the arrow extending from line XX.

[0083] In this embodiment, case 20 is provided with a central support pillar 26 at the center of bottom wall 22. Central support pillar 26 extends in the axial direction of coil 11, passing through the center of coil 11. As shown in FIG. 10 , the end of central support pillar 26 opposite bottom wall 22 contacts covering wall 25, indicated by the two-dot chain line, thereby allowing central support pillar 26 to support covering wall 25. Central support pillar 26 has a rectangular cross section with rounded corners, but the shape is not particularly limited. In addition, magnetic shield member 40 is provided with a hole through which central support pillar 26 passes.

[0084] The central support 26 has a core 26C and an outer peripheral covering 26D. The core 26C rises from the bottom wall 22. The outer peripheral covering 26D covers the outer peripheral surface of the core 26C and forms the outer peripheral surface of the central support 26. The central support 26 includes two materials, one of which, a first central support material, is conductive, and the other, a second central support material, is magnetic. The magnetic second central support material forms the outer peripheral covering 26D and forms the outer peripheral surface of the central support 26. Meanwhile, the conductive first central support material forms the core 26C. The entire outer peripheral surface of the core 26C is covered by the outer peripheral covering 26D.

[0085] In this embodiment, the outer covering portion 26D is made of ferrite, and the core portion 26C is made of aluminum. However, these materials are not particularly limited. The outer covering portion 26D may be made of silicon steel, soft electromagnetic iron, or amorphous metal. The outer covering portion 26D may also be made of a material containing two or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal. The outer covering portion 26D may also be made of a material containing a plurality of particles made of one or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal, and a resin containing the plurality of particles.

[0086] The core portion 26C may be formed integrally with the bottom wall portion 22. Alternatively, the core portion 26C and the bottom wall portion 22 may be formed separately and then joined together.

[0087] In this embodiment, the generation of eddy currents in central support 26 can be suppressed compared to when central support 26 is entirely made of a conductive material with a relatively low electrical resistance, such as aluminum. This can improve the inductance of coil 11 and reduce losses. This can prevent the performance of coil 11 from being affected by the components surrounding it.

[0088] <Fifth embodiment> Next, a coil device 10E according to a fifth embodiment will be described. Fig. 11 is a perspective view of the coil device 10E, specifically, a perspective view of a central support 26 included in the coil device 10E. Components in this embodiment that are the same as those in the first to fourth embodiments are designated by the same reference numerals, and redundant description will be omitted.

[0089] As shown in Figure 11, the central support 26 in this embodiment has a core 26C and an outer peripheral covering 26D, similar to the fourth embodiment. However, only the distal end portion of the outer peripheral surface of the core 26C is covered by the outer peripheral covering 26D. The core 26C tapers from the midpoint between the base end and the distal end to the distal end. The outer peripheral covering 26D is provided on the tapered portion of the core 26C.

[0090] In this embodiment, the inductance of coil 11 can be improved and loss can be reduced compared to when central support 26 is entirely made of a conductive material with a relatively low electrical resistance, such as aluminum. This prevents the performance of coil 11 from being affected by the components surrounding coil 11. Furthermore, a large cross-sectional area of ​​core portion 26C can be ensured, which is even more advantageous in terms of durability.

[0091] Sixth Embodiment Next, a coil device 10F according to a sixth embodiment will be described. Fig. 12 is a perspective view of the coil device 10F, specifically, a perspective view of a central support 26 included in the coil device 10F. Components in this embodiment that are the same as those in the first to fifth embodiments are assigned the same reference numerals, and redundant description will be omitted.

[0092] 12, the central support 26 in this embodiment has a tip-side column portion 26A that includes one end of the coil 11 in the axial direction, and a base-side column portion 26B that is the remaining portion located between the tip-side column portion 26A and the bottom wall portion 22. The tip-side column portion 26A is made of ferrite, and the base-side column portion 26B is made of aluminum.

[0093] The distal column portion 26A is formed of ferrite, but is not limited thereto and may be formed of resin, silicon steel, soft electromagnetic iron, or amorphous metal. The distal column portion 26A may also be formed of a material containing two or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal. The distal column portion 26A may also be formed of a material containing a plurality of particles of one or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal, and a resin containing the plurality of particles.

[0094] When the tip side pillar portion 26A is made of only resin, it is desirable to make it of fiber reinforced plastic.

[0095] In this embodiment, the generation of eddy currents in central support 26 can be suppressed compared to when central support 26 is entirely made of a conductive material with a relatively low electrical resistance, such as aluminum. This can improve the inductance of coil 11 and reduce losses. This can prevent the performance of coil 11 from being affected by the components surrounding it.

[0096] Seventh Embodiment Next, a coil device 10G according to a seventh embodiment will be described. Fig. 13 is a perspective view of the coil device 10G, in which a part of the coil device 10G is cut away. Fig. 14 is a cross-sectional view of the coil device 10G. Components in this embodiment that are the same as those in the first to sixth embodiments are designated by the same reference numerals, and redundant description will be omitted.

[0097] The coil components according to the first to sixth embodiments described above have a structure suitable for the power transmitter 1 when used in a wireless power transmission system S. On the other hand, a coil component 10G according to a seventh embodiment described below has a structure suitable for the power receiver 2. However, the coil components according to the first to sixth embodiments may be used on the power receiver 2 side, and the coil component 10G according to this embodiment may be used on the power transmitter 1 side.

[0098] As shown in FIG. 13 , the coil device 10G includes a coil 11, a case 120, a first heat dissipation member 31, a second heat dissipation member 32, a magnetic shield member 40, and a covering wall portion 125. Similar to the above-described embodiments, the case 120 includes a bottom wall portion 122 and a side wall portion 123 rising from the bottom wall portion 122. However, the configuration of the components disposed on the bottom wall portion 122 differs from the above-described embodiments. That is, the coil 11, the first heat dissipation member 31, the magnetic shield member 40, the second heat dissipation member 32, and the covering wall portion 125 are disposed on the bottom wall portion 22 in this order. Note that components corresponding to the first connection terminal 51 and the second connection terminal 52 shown in FIG. 2 are not shown.

[0099] 14, in this embodiment, the coil 11 is in contact with the bottom wall portion 122. The coil 11 is disposed on the flat surface of the bottom wall portion 122, but may be embedded in the bottom wall portion 122. The side wall portion 123 is located on the outer periphery of the coil 11 disposed on the bottom wall portion 122.

[0100] The side wall portion 123 has an outer peripheral portion 123A and an inner peripheral portion 123B located radially inward of the outer peripheral portion 123A, and the inner peripheral portion 123B forms the inner peripheral surface of the side wall portion 123. In this embodiment, the outer peripheral portion 123A and the bottom wall portion 122 are integrally formed and made of the same material. On the other hand, the inner peripheral portion 123B is separate from the outer peripheral portion 123A and the bottom wall portion 122 and made of a different material from the outer peripheral portion 123A and the bottom wall portion 122. In other words, the side wall portion 123 includes two types of materials, one of which forms the outer peripheral portion 123A and the other of which forms the inner peripheral portion 123B.

[0101] Specifically, the material forming outer circumferential portion 123A is a resin, and the material forming inner circumferential portion 123B is a magnetic material. Specifically, in this embodiment, the resin forming outer circumferential portion 123A is a fiber-reinforced plastic, but there is no particular limitation as long as it is insulating.

[0102] On the other hand, the magnetic material forming the inner circumferential portion 123B is ferrite. That is, the inner circumferential surface of the sidewall portion 123 is formed of ferrite. However, the magnetic material forming the inner circumferential portion 123B is not limited to ferrite and may be formed of silicon steel, soft magnetic iron, or amorphous metal. Furthermore, the inner circumferential portion 123B may be formed of a material containing two or more of ferrite, silicon steel, soft magnetic iron, and amorphous metal. Furthermore, the inner circumferential portion 123B may be formed of a material containing a plurality of particles made of one or more of ferrite, silicon steel, soft magnetic iron, and amorphous metal, and a resin containing the plurality of particles. Furthermore, the entire sidewall portion 123 may be formed of a material containing a plurality of particles made of one or more of ferrite, silicon steel, soft magnetic iron, and amorphous metal, and a resin containing the plurality of particles.

[0103] FIG. 15 is a perspective view of the coil 11 and the case 120. FIG. 16 is an exploded view of the coil 11 and the case 120 shown in FIG. 15. In this embodiment, as shown in FIG. 16, the case 120 is formed from a sheet base material 120M having a bottom wall portion 122 and side wall forming portions 123M integrally formed therewith, each of which is connected along each of the four sides of the bottom wall portion 122. Specifically, the sheet base material 120M is press-molded using a mold to raise the side wall forming portions 123M, and adjacent side wall forming portions 123M are connected to form a case shape with one open end. Here, before this press molding, inner surface forming sheets 123N made of ferrite are placed on the side wall forming portions 123M, respectively, and extend along the side wall forming portions 123M. As a result, after press molding, the inner peripheral portions 123B of the side wall portions 123 are formed by the inner surface forming sheets 123N, as shown in FIG. 15. The method for forming the case 120 is not limited to the example described above, and it may be formed by other methods.

[0104] The first heat dissipation member 31 and the second heat dissipation member 32 are provided to dissipate heat from the coil 11. The first heat dissipation member 31 and the second heat dissipation member 32 may be formed from a material in which a resin contains a non-magnetic inorganic material, such as ceramics, that has a relatively high thermal conductivity. The first heat dissipation member 31 is formed in a sheet shape and is disposed between the coil 11 and the magnetic shield member 40. In this embodiment, the coil 11 and the magnetic shield member 40 are separated in the axial direction of the coil 11 by the first heat dissipation member 31. The second heat dissipation member 32 is disposed between the magnetic shield member 40 and the covering wall portion 125. In this embodiment, the second heat dissipation member 32 is columnar, and a plurality of second heat dissipation members 32 are disposed between the magnetic shield member 40 and the covering wall portion 125. Furthermore, when viewed in the radial direction of the coil 11, the inner circumferential portion 123B overlaps with the coil 11 and the magnetic shielding member 40 in the radial direction of the coil 11, and in the example shown, the inner circumferential portion 123B contacts the coil 11 and the magnetic shielding member 40 in the radial direction of the coil 11.

[0105] The covering wall portion 125 is made of aluminum, but the material is not particularly limited. In this embodiment, the covering wall portion 125 is made of a conductive metal, so that the covering wall portion 125 functions as a magnetic shield and also has excellent heat dissipation properties. Heat from the coil 11 is conducted from the first heat dissipation member 31 to the second heat dissipation member 32 via the magnetic shield member 40, and then from the second heat dissipation member 32 to the covering wall portion 125, and is then dissipated to the outside.

[0106] In the present embodiment described above, the side wall portion 123 contains two types of materials, one of which is resin and the other of which is magnetic. Specifically, the side wall portion 123 contains fiber-reinforced plastic and ferrite. In this case, eddy currents are not generated in the side wall portion 123. Furthermore, the ferrite forming the inner circumferential surface of the side wall portion 123 prevents the magnetic field generated by the coil 11 from escaping to the outside. This can improve inductance and reduce loss.

[0107] Therefore, coil device 10G according to the present embodiment can prevent performance degradation of coil 11 due to the influence of members around coil 11. Specifically, it is possible to prevent a situation in which inductance is significantly reduced and loss is significantly increased due to the influence of side wall portion 123 around coil 11 and other surrounding metal members, and therefore it is possible to prevent performance degradation of coil 11 due to the influence of members around coil 11.

[0108] <Evaluation by simulation> Next, we will explain the results of a simulation evaluation of the coil performance of the above embodiment. The simulation was performed by setting various conditions such as the dimensions and materials of each part of the coil component, and the frequency of the supplied high-frequency current, and then analyzing the magnetic field using the finite element method. Then, based on the simulated magnetic field, the Q value, inductance (L), impedance (Z), loss (LOSS), etc. were derived.

[0109] The simulation was performed using Femtet (registered trademark) manufactured by Murata Software Co., Ltd.

[0110] In the simulations described below, eight patterns of magnetic field simulations were performed on the coil component according to the embodiment (Simulation Examples 1 to 8), and the results were compared with Comparative Examples 1 and 2.

[0111] The following conditions were set as common conditions for Simulation Examples 1 to 8 and Comparative Examples 1 and 2. The coils 11 are of the same spiral shape. The supplied high frequency current is 40 A and the frequency is 85 KHz. The coil material is copper, and the electrical conductivity is 6.45 x 10 7 [S / m]. The coil and air layer were divided into 300,000 to 500,000 meshes and the simulation was carried out.

[0112] In Simulation Examples 1 to 8, the shape of the case 20 was changed in various ways as follows, and the Q value, inductance, impedance, and loss (LOSS) were derived from an analysis of the simulated magnetic field. The loss is the total of losses that can occur in the coil components, such as loss in the coil and loss due to the case shape.

[0113] Simulation example 1 (SIM-1) Simulation example 1 is a simulation of a coil device 10F (FIG. 12) according to the sixth embodiment. The case 20 has only a central support 26, and does not have support columns 24 at the four corners. The tip-side support portion 26A shown in FIG. 12 is formed of resin, and the base-side support portion 26B is formed of aluminum. The bottom wall portion 22 of the case 20 is formed of aluminum. Furthermore, although the side wall portion 23 of the case 20 contains ferrite and aluminum, this was removed for simplicity of the simulation.

[0114] Simulation example 2 (SIM-2) Simulation example 2 is a simulation of the coil device 10F according to the sixth embodiment, but the materials are changed from those in simulation example 1. Specifically, the distal column portion 26A is made of ferrite, and the proximal column portion 26B is made of aluminum. The other conditions are the same as those in simulation example 1.

[0115] Simulation example 3 (SIM-3) Simulation example 3 is a simulation of a coil device 10D (FIG. 8) according to the fourth embodiment. The case 20 has only a central support 26, and does not have support columns 24 at the four corners. The outer covering portion 26D shown in FIG. 8 is made of ferrite, and the core portion 26C is made of aluminum. The relative magnetic permeability of ferrite is 3000. The other conditions are the same as those of simulation example 1.

[0116] Simulation example 4 (SIM-4) Simulation example 4 is a simulation of coil device 10D according to the fourth embodiment. In simulation example 4, the magnetic permeability of ferrite forming outer covering portion 26D is 10 (H / m). Other conditions are the same as in simulation example 3.

[0117] Simulation example 5 (SIM-5) Simulation example 5 is a simulation of a modified example in which support posts 24 are removed from coil device 10A according to the first embodiment. In simulation example 5, tip end portion 23A of side wall 23 of case 20 is formed from resin, and base end portion 23B is formed from aluminum. Case 20 does not have support posts. Bottom wall 22 of case 20 is formed from aluminum.

[0118] Simulation example 6 (SIM-6) Simulation example 6 is a simulation of a configuration in which support columns 24 are added to the four corners of Simulation example 5. However, the support columns 24 are entirely made of aluminum. The other conditions are the same as those of Simulation example 5.

[0119] Simulation example 7 (SIM-7) In Simulation Example 7, the material of the pillars 24 at the four corners is different from that in Simulation Example 6, but the other conditions are the same as in Simulation Example 6. In Simulation Example 7, the tip-side pillar portion 24A of the pillar 24 is made of resin, and the base-side pillar portion 24B is made of aluminum.

[0120] Comparison Example 1 Comparative Example 1 is a simulation of Simulation Example 1 in which the central support 26 is entirely made of aluminum.

[0121] Comparative Example 2 Comparative Example 2 is a simulation of Simulation Example 5 in which the side wall portion 23 is entirely made of aluminum.

[0122] The simulation results of the Q value, inductance L, impedance Z, and loss LOSS for each of Simulation Examples 1 to 8 and Comparative Examples 1 and 2 are shown in Table 1 below.

[0123] [Table 1]

[0124] Comparing Simulation Examples 1 to 4, which relate to an embodiment with the same basic case shape, with Comparative Example 1, it can be seen that Simulation Examples 1 to 4 have better performance than Comparative Example 1. That is, the Q values ​​and inductances of Simulation Examples 1 to 4 are higher than Comparative Example 1. The impedances and losses of Simulation Examples 1 to 4 are lower than Comparative Example 1. This confirms the effect of the present embodiment, that is, the ability to prevent the performance of the coil from being degraded by the influence of the members surrounding the coil.

[0125] Comparing Simulation Examples 5 to 7, which relate to an embodiment with the same basic case shape, with Comparative Example 2, it can be seen that Simulation Examples 5 to 7 have better performance than Comparative Example 2. That is, the Q values ​​and inductances of Simulation Examples 5 to 7 are higher than Comparative Example 2. It can also be seen that the impedances and losses of Simulation Examples 5 to 7 are lower than Comparative Example 2. This confirms the effect of this embodiment, that is, the ability to prevent the performance of the coil from being affected by the components around the coil from deteriorating.

[0126] Next, the results of a simulation evaluation of the coil performance of the coil device 10G according to the seventh embodiment will be described. The simulation was performed by setting various conditions, such as the dimensions and materials of each part of the coil device and the frequency of the supplied high-frequency current, and then analyzing the magnetic field using the finite element method. Then, based on the simulated magnetic field, the inductance (L), case loss, and coil loss were derived.

[0127] The simulation was performed using Femtet (registered trademark) manufactured by Murata Software Co., Ltd., as in the above-mentioned simulation.

[0128] In a simulation of coil device 10G according to the seventh embodiment, resin was used to form bottom wall 122 and outer peripheral portion 123A of side wall 123 of case 120. Ferrite was used as a magnetic material to form inner peripheral portion 123B of side wall 123. Aluminum was used to form covering wall 125. In this simulation, the conditions regarding the coil material and mesh size used for division were the same as those in Simulation Examples 1 to 7. Meanwhile, the supplied high-frequency current was varied between 20 kHz and 200 kHz, and the inductance, case loss, and coil loss were derived from an analysis of the simulated magnetic field. Note that case loss is the total loss generated in case 120 and covering wall 125. The simulation results for coil device 10G were compared with those of Comparative Example 3, in which the entire side wall 123 was formed of resin.

[0129] Fig. 17 is a graph showing simulation results related to inductance. Fig. 18 is a graph showing simulation results related to case loss. Fig. 19 is a graph showing simulation results related to coil loss. The horizontal axis of each graph indicates frequency (KHz). The vertical axis of Fig. 17 indicates inductance (μH). The vertical axes of Figs. 18 and 19 indicate loss (W). The simulation results for coil device 10G are indicated by "◯" in each graph, and the simulation results for the comparative example are indicated by "X".

[0130] In Fig. 17, the inductance of the embodiment is higher than that of Comparative Example 3 over a wide frequency range (50 KHz to 200 KHz). In Fig. 18, the loss (case) of the embodiment is lower than that of Comparative Example 3 over the entire frequency range. In Fig. 19, the difference between the loss (coil) of the embodiment and Comparative Example 3 is small. From the above results, it can be seen that the reduction in loss in the case suppresses the decrease in inductance. From the above simulations, it can be confirmed that this embodiment has the effect of suppressing the decrease in coil performance due to the influence of the members around the coil.

[0131] In the above simulations, the relative permeability of the magnetic material forming the inner circumferential portion 123B was set to 10, but the trends shown in Fig. 17 to Fig. 19 were observed in the range of relative permeability from 10 to 50. Therefore, it is estimated that even if the relative permeability is a relatively small value, the effect of suppressing the deterioration of the coil performance can be obtained.

[0132] <Eighth embodiment> Next, a coil device 10H according to an eighth embodiment will be described. Fig. 20 is a plan view of the coil device 10H. Fig. 21 is a perspective view of the coil device 10H. Fig. 22 is a side view of the coil device 10H. Components in this embodiment that are the same as those in the first to seventh embodiments are given the same reference numerals, and redundant description will be omitted.

[0133] As shown in FIGS. 20 to 22 , a coil device 10H according to this embodiment includes an intermediate support 240 that passes through the coil 11 between its inner and outer peripheral portions. The coil 11 has a plurality of winding portions that are arranged radially and connected to form a spiral shape. In the coil 11, the gap between adjacent winding portions at a position toward the center in the radial direction is larger than the gap between other adjacent winding portions. The intermediate support 240 passes between the adjacent winding portions where this gap is larger. A hole is formed in the magnetic shield member 40 to allow the intermediate support 240 to pass through.

[0134] The coil 11 has a rectangular shape in a plan view. The intermediate supports 240 are provided on diagonal lines of the coil 11, and more specifically, are provided at four positions on the diagonal lines that are equidistant from the central axis C of the coil 11. However, the positions and number of the intermediate supports 240 are not particularly limited. The intermediate supports 240 may be formed together with the supports 24 and the central support 26 described in the above embodiment.

[0135] The structure of the intermediate support 240 may be the same as the structure of the support 24 described in the first to third embodiments. That is, the intermediate support 240 may include two types of materials, one of which, the first support material, is conductive and the other, the second support material, is magnetic. The intermediate support 240 may also include two types of materials, one of which, the first support material, is conductive and the other, the second support material, is insulating.

[0136] Although the embodiments of the present disclosure have been described above, various modifications may be made to the above-described embodiments, and such modifications are also within the technical scope of the present disclosure. [Explanation of symbols]

[0137] S...Power transmission system 1...Power transmission device 1A...High frequency current supply unit 2...Power receiving device 2A...Conversion unit 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H... Coil parts 11...Coil 11A...Inner circumference end 11B...Outer edge 20,120…case 22,122...Bottom wall 23,123...Side wall 23A…Tip side part 23B…Proximal part 123A…Outer peripheral part 123B...Inner circumference 123M…Side wall forming part 24...post 24A…Tip side column part 24B…Proximal column part 24C…core part 24D…Outer sheathing part 240...Intermediate support 25,125…Coated wall part 26...Central pillar 26A…Tip side pillar part 26B…Proximal column part 26C…core part 26D...Outer covering part 120M...sheet base material 123M…Side wall forming part 123N...Inner surface forming sheet 31...First heat dissipation member 32...Second heat dissipation member 40...Magnetic shielding member 51...First connection terminal 52...Second connection terminal C…Central axis line

Claims

1. A coil and a case having a side wall portion positioned on an outer periphery of the coil, the sidewall portion comprises two materials; One of the two materials is electrically conductive and the other is magnetic; the other material forms a portion including an end portion of the side wall portion on one side in the axial direction of the coil, A coil component, wherein the one material forms a portion of the side wall portion that is different from a portion including the end portion.

2. the one material is a metal; 2. The coil component according to claim 1, wherein the other material has a higher magnetic permeability and a higher electrical resistance than the one material.

3. The coil component according to claim 2 , wherein the other material includes at least one of ferrite, silicon steel, soft magnetic iron, and amorphous metal.

4. 3. The coil component according to claim 2, wherein the other material includes particles made of one or more of ferrite, silicon steel, soft electromagnetic iron, and amorphous metal, and a resin containing the particles.

5. A coil, a case having a side wall portion positioned on an outer periphery of the coil, the sidewall portion comprises two materials; One of the two materials is conductive and the other is insulating; the other material forms a portion including an end portion of the side wall portion on one side in the axial direction of the coil, A coil component, wherein the one material forms a portion of the side wall portion that is different from a portion including the end portion.

6. the one material is a metal; The coil component according to claim 5 , wherein the other material is a resin.

7. A coil, a case having a side wall portion positioned on an outer periphery of the coil; a support extending in the axial direction of the coil; the sidewall portion comprises two materials; one of the two materials of the sidewall portion is electrically conductive and the other is magnetic; The strut comprises two materials; A coil component, wherein one of the two materials of the support pillars, a first support pillar material, is electrically conductive, and the other, a second support pillar material, is magnetic.

8. A coil, a case having a side wall portion positioned on an outer periphery of the coil; a support extending in the axial direction of the coil; the sidewall portion comprises two materials; one of the two materials of the sidewall portion is conductive and the other is insulating; The strut comprises two materials; A coil component, wherein one of the two materials of the support pillars, a first support pillar material, is electrically conductive, and the other, a second support pillar material, is magnetic.

9. A coil, a case having a side wall portion positioned on an outer periphery of the coil; a support extending in the axial direction of the coil; the sidewall portion comprises two materials; one of the two materials of the sidewall portion is electrically conductive and the other is magnetic; The strut comprises two materials; A coil component, wherein one of the two materials of the support pillars, a first support pillar material, is conductive, and the other, a second support pillar material, is insulating.

10. A coil; a case having a side wall portion positioned on an outer periphery of the coil; a support extending in the axial direction of the coil; the sidewall portion comprises two materials; One of the two materials is conductive and the other is insulating; The strut comprises two materials; A coil component, wherein one of the two materials, the first strut material, is conductive, and the other, the second strut material, is insulating.

11. the second strut material forms a portion including an end of the strut on one axial side of the coil; The coil component according to claim 7 , wherein the first strut material forms a portion of the strut that is different from a portion including the end portion.

12. the second strut material forms an outer periphery of the strut; The coil component of claim 11 , wherein the portion of the strut formed by the first strut material is at least partially covered by the second strut material.

13. The coil component according to claim 1 , further comprising a magnetic shield member arranged to overlap the coil when viewed in the axial direction of the coil.

14. The coil component according to claim 13 , wherein the magnetic shielding member includes ferrite.

15. The coil component according to claim 1 , wherein the coil has a spiral shape.

16. The coil component according to claim 1 , wherein the coil is plate-shaped.

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

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

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

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