Coil unit

Abstract

The invention provides a coil unit. A coil unit (10) is provided with a coil (13) and an iron core member (15). The coil (13) receives AC power transmitted in a non-contact manner from a power transmission device. The core member (15) is formed in a sheet shape by means of a directional magnetic material. When the power transmission device faces the coil (13), the iron core member (15) is disposed on the rear side of the coil (13) when viewed from the power transmission device. The coil (13) and the core member (15) each have a rectangular ring-shaped outer shape. The orientation direction of the iron core member (15) is orthogonal to the direction along the winding direction of the coil (13) in the mutually facing linear portions (13b, 15b) of the coil (13) and the iron core member (15).

Description

Technical Field

[0001] The present invention relates to a coil unit. Background Art

[0002] In recent years, more and more people have been conducting research and development related to charging and power supply in vehicles equipped with secondary batteries in order to ensure convenient, reliable, sustainable and advanced energy use, which contributes to energy efficiency.

[0003] Conventionally, in contactless power transmission systems that supply power to a vehicle from outside the vehicle through contactless power transmission, there is a known system that includes a back plate formed of a magnetic material in order to guide the magnetic flux around each coil on the power transmitting side and the power receiving side (for example, see Japanese Patent Gazette No. 7232960). Summary of the invention

[0004] In the technology related to charging and supplying power in a vehicle equipped with a secondary battery, when non-contact power transmission is performed on the vehicle, it is desired to ensure the desired robustness in the vehicle-mounted receiving-side unit and reduce the magnetic flux (leakage magnetic flux) other than the main magnetic flux interlinked with each coil on the power transmission side and the power reception side, so as to improve the coupling coefficient. For example, in the case of a non-contact power transmission system of the above-mentioned prior art having a back plate formed of a magnetic material such as a ferrite core, there is a possibility of damage such as cracking or defect of the back plate due to vibration of the vehicle body, and there is a problem of increasing the weight of the receiving-side unit.

[0005] An object of the aspect of the present invention is to provide a coil unit that can suppress the occurrence of damage to a magnetic member and reduce leakage flux to improve the coupling coefficient. In addition, the aspect of the present invention further contributes to energy efficiency.

[0006] The coil unit of the first scheme of the present invention comprises: a coil, which receives AC power transmitted by non-contact from a power transmission device; and an iron core component, which is formed into a sheet shape by a directional magnetic material, and when the power transmission device and the coil are facing each other, the iron core component is arranged on the rear side of the coil when viewed from the power transmission device, wherein the orientation direction of the iron core component is orthogonal to the direction of the coil along the winding direction.

[0007] The second scheme may be based on the coil unit described in the above-mentioned first scheme, and the outer shapes of the coil and the core component may be rectangular rings, and in at least the straight line portions facing each other of the coil and the core component, the orientation direction is orthogonal to the direction along the winding direction.

[0008] According to a third aspect, in the coil unit according to the first or second aspect, the core member may be formed by combining at least four isosceles trapezoidal members having a base angle of 45° obtained by cutting a sheet-like belt-like member.

[0009] According to the first scheme, the orientation direction of the core member formed of the directional magnetic material is orthogonal to the direction along the winding direction of the coil, so that the magnetic flux around the coil can be guided to the main magnetic flux, and the leakage magnetic flux (magnetic flux other than the main magnetic flux) can be reduced, thereby improving the coupling coefficient. By the orientation direction of the core member 15, even if it is in a sheet shape, the increase of iron loss can be suppressed, and the so-called Q value can be improved to ensure the desired output.

[0010] In the case of the above-mentioned second scheme, since the outer shapes of the coil and the core component are respectively rectangular ring-shaped, the orientation direction of the core component can be easily made orthogonal to the direction of the coil along the winding direction in the straight line parts facing each other, which can easily achieve the reduction of leakage magnetic flux and the improvement of coupling coefficient.

[0011] In the case of the third aspect, the rectangular ring-shaped core member is formed by combining at least four isosceles trapezoidal members obtained from the belt-shaped member, thereby suppressing a decrease in yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is an exploded perspective view showing the structure of the coil unit in the embodiment of the present invention.

[0013] Figure 2 The coil unit in the embodiment of the present invention is Figure 1 The position of the line AA shown is a cross-sectional view obtained by cutting along the ZX plane.

[0014] Figure 3 The diagram shows a core member formed of a directional magnetic material in a coil unit according to an embodiment of the present invention and a belt-shaped member for obtaining four members forming the core member.

[0015] Figure 4 It is a diagram showing magnetic flux around the coil unit and the coil unit of the power transmission device according to the embodiment of the present invention.

[0016] Figure 5 The graph shows an example of the correspondence relationship between the inter-coil distance (distance in a direction orthogonal to the opposing direction) and the KQ product (product of coupling coefficient and quality factor) between the coil unit according to the embodiment of the present invention and the coil unit of the comparative example and the coil unit of the power transmission device. DETAILED DESCRIPTION

[0017] Hereinafter, a coil unit according to an embodiment of the present invention will be described with reference to the drawings.

[0018] Figure 1 It is an exploded perspective view showing the structure of coil unit 10 in the embodiment. Figure 2 The coil unit 10 in the embodiment is Figure 1 The position of the line AA shown is a cross-sectional view obtained by cutting along the ZX plane.

[0019] Hereinafter, the directions of the X-axis, Y-axis, and Z-axis that are orthogonal to each other in three-dimensional space are directions parallel to the axes. Figure 1 and Figure 2 As shown, the Z-axis direction is parallel to the up-down direction of a moving body such as a vehicle equipped with the coil unit 10, the X-axis direction is parallel to the front-rear direction of the moving body, and the Y-axis direction is parallel to the left-right direction of the moving body. For example, the positive direction of the Z-axis is the upward direction of the moving body, the positive direction of the X-axis is the front direction of the moving body, and the positive direction of the Y-axis is the right direction of the moving body.

[0020] The coil unit 10 of the embodiment is mounted on, for example, a vehicle that receives power from the outside through contactless power transmission. The coil unit 10 is fixed to, for example, the lower part of a frame-shaped subframe provided at the lower part of the vehicle body. The coil unit 10 constitutes a power transmission device T (see below) that receives power from the outside through contactless power transmission. Figure 4 ) The part of a power receiving device that receives AC power.

[0021] like Figure 1 and Figure 2 As shown, the coil unit 10 includes, for example, a frame 11 , a first cover 12 , a coil 13 , an insulating member 14 , a core member 15 , a back member 16 , an inner member 17 , and a second cover 18 .

[0022] The outer shape of the frame 11 is formed in a rectangular frame shape, for example. The frame 11 includes, for example, a first housing portion 21 in which the coil 13, the insulating member 14, and the core member 15 described later are arranged, and a second housing portion 22 in which the substrate 23 and the capacitor 24 described later are arranged. The first housing portion 21 is provided, for example, in a manner of surrounding the lower side in the up-down direction and the inner side and the outer side in the direction perpendicular to the up-down direction with respect to the coil 13, the insulating member 14, and the core member 15 described later. The second housing portion 22 is provided, for example, at a position closer to the rear side than the first housing portion 21 in the front-to-back direction. The second housing portion 22 is provided, for example, in a manner of surrounding the lower side in the up-down direction and the outer side in the direction perpendicular to the up-down direction with respect to the substrate 23 and the capacitor 24 described later.

[0023] The frame 11 includes, for example, a surface 11A having a plurality of grooves 11a formed thereon. The surface 11A of the frame 11 (i.e., the surface on the lower side in the up-down direction, i.e., the lower surface) is exposed to the outside below the vehicle body. The plurality of grooves 11a are formed, for example, along the front-rear direction, along the flow direction of the wind (travel wind) received by the vehicle when it is traveling.

[0024] The frame 11 includes, for example, a plurality of heat dissipation members 11 b protruding inward from an inner surface 11B that is on the back side relative to the surface 11A. The outer shape of the heat dissipation members 11 b is, for example, a plate-like fin type. The plurality of heat dissipation members 11 b are in contact with the coil 13 .

[0025] The outer shape of the first cover 12 is, for example, a rectangular plate having a through hole 12a formed in the thickness direction. The first cover 12 is provided, for example, in a manner of surrounding the upper side in the vertical direction with respect to the coil 13, the insulating member 14, and the core member 15 described later. The first cover 12 forms a housing space for housing the coil 13, the insulating member 14, and the core member 15 between the first cover 12 and the inner surface 11B of the frame 11. The first cover 12 closes the open end of the first housing portion 21 of the frame 11 housing the coil 13, the insulating member 14, and the core member 15.

[0026] The outer shape of the coil 13 is formed, for example, in a rectangular spiral shape along the inner surface 11B of the frame 11. The wire of the coil 13 is in direct contact with the plurality of heat dissipating members 11b.

[0027] The insulating member 14 has an outer shape of, for example, a rectangular sheet having through holes 14 a formed in the thickness direction. The insulating member 14 is formed of a material having electrical insulation properties.

[0028] The outer shape of the core member 15 is formed, for example, in a rectangular sheet shape with a through hole 15a formed in the thickness direction. The core member 15 is formed of a magnetic material with a relatively large magnetic permeability, such as a non-directional (isotropic) magnetic material such as ferrite, or a directional (anisotropic) magnetic material such as an electromagnetic steel sheet such as a silicon steel sheet, or a soft magnetic material such as a nanocrystalline soft magnetic material.

[0029] Figure 3 The diagram shows core member 15 formed of a directional magnetic material in coil unit 10 according to the embodiment and belt-shaped member 30 for obtaining four members 31 forming core member 15 .

[0030] like Figure 3 As shown, the core member 15 formed of the directional magnetic material is obtained, for example, from a strip member 30 of a sheet-like laminated body, which is formed by laminating a plurality of thin-film-like magnetic sheets formed of the directional magnetic material in the thickness direction. The orientation direction D of the strip member 30 is, for example, parallel to a direction (width direction) orthogonal to the thickness direction and the length direction of the strip member 30.

[0031] For example, the rectangular ring-shaped iron core member 15 is formed by combining four members 31 obtained from the sheet-shaped belt-shaped member 30. The four members 31 are obtained by, for example, cutting the belt-shaped member 30 in the thickness direction along a plurality of cutting lines 30a set at an inclination of 45° relative to the orientation direction D of the belt-shaped member 30. The outer shape of each member 31 is an isosceles trapezoidal shape having a base angle of 45° when viewed from the thickness direction. The four members 31 are joined together at the waists of adjacent members 31 to form a rectangular sheet-shaped iron core member 15 having a through hole 15a formed in the thickness direction.

[0032] like Figure 1 and Figure 2 As shown in FIG. 1 , the outer shape of the back member 16 is, for example, a rectangular plate having a through hole formed in the thickness direction. The outer shape of the inner member 17 is, for example, a box-shaped shape having a rectangular frame-shaped wall portion and a cover portion closing the lower open end of the wall portion. The inner member 17 protrudes downward in the vertical direction from the peripheral edge portion surrounding the through hole of the back member 16. The back member 16 and the inner member 17 are integrally formed of a magnetic material having a relatively large magnetic permeability, such as an electromagnetic steel sheet such as a silicon steel sheet.

[0033] The back member 16 is disposed, for example, on the upper side in the up-down direction with respect to the first cover 12 .

[0034] The inner member 17 is inserted into the through holes 12a, 15a, 14a of the first cover 12, the core member 15, and the insulating member 14, the hollow region 13a of the coil 13, and the through hole 11c in the thickness direction of the frame 11. The inner member 17 protrudes downward from the surface 11A of the frame 11, for example.

[0035] The second cover 18 has a hip roof shape, for example. The second cover 18 closes the open end of the second housing portion 22 of the housing 11 housing electrical devices such as a substrate 23 and a capacitor 24.

[0036] The substrate 23 fixes a plurality of electronic components constituting a part of the power receiving device, such as the capacitor 24 .

[0037] The capacitor 24 is, for example, a resonance capacitor connected to the coil 13. The plurality of capacitors 24 are fixed to the substrate 23 and are in contact with the inner surface 11B of the housing 11 via a heat conductive material such as heat conductive paste.

[0038] In the coil unit 10 , the coil 13 , the insulating member 14 , and the core member 15 are sequentially stacked in the up-down direction and arranged in the first housing portion 21 of the frame body 11 .

[0039] The orientation direction D of the core member 15 formed of a directional magnetic material is orthogonal to the direction along the winding direction of the coil 13. For example, when the outer shapes of the coil 13 and the core member 15 are each rectangular ring-shaped, the coil 13 has a straight portion 13b, and the core member 15 has a straight portion 15b, and at least in the straight portions 13b and 15b facing each other in the up-down direction, the orientation direction D is orthogonal to the direction along the winding direction.

[0040] Figure 4 1 is a diagram showing magnetic flux around the coil unit 10 and the coil unit of the power transmission device T according to the embodiment. Figure 4 In the illustrated coil unit 10 , the inner member 17 inserted into the hollow region 13 a of the coil 13 is omitted.

[0041] Figure 4 The coil unit of the power transmission device T shown in the figure includes, for example, a coil 41, a core member 42, and an inner member 43. The outer shape of the coil 41 is, for example, a rectangular spiral shape. The outer shape of the core member 42 is, for example, a rectangular plate shape. The outer shape of the inner member 43 is, for example, a rectangular box shape.

[0042] In a state where the coil 13 of the coil unit 10 of the embodiment faces the coil 41 of the power transmission device T, the core member 15 of the coil unit 10 is arranged on the rear side of the coil 13 when viewed from the power transmission device T, and the core member 42 is arranged on the rear side of the coil 41 when viewed from the coil unit 10 of the embodiment. The inner member 43 protrudes from the core member 42 toward the coil unit 10 side and is inserted into the hollow core region of the coil 41, for example.

[0043] The core members 15, 42 and the inner members 17, 43 of the coil unit 10 and the power transmission device T guide the magnetic flux around the coils 13, 41 to the main magnetic flux F. The core member 15 of the coil unit 10, which is formed of a directional magnetic material, guides the magnetic flux in an orientation direction D that is orthogonal to the direction C along the winding direction of the coil 13.

[0044] Figure 5 The graph shows an example of the correspondence relationship between the inter-coil distance (the distance in the direction orthogonal to the opposing direction) and the KQ product (the product of the coupling coefficient and the quality factor) between the coil unit on the power receiving side and the coil unit of the power transmitting device T in the embodiment and the comparative example.

[0045] exist Figure 5In the illustrated embodiment, the core member 15 of the coil unit 10 is in the form of a sheet formed of a nanocrystalline soft magnetic material, and the core member 42 of the power transmission device T is in the form of a plate formed of ferrite. In the comparative example, the core member on the power receiving side and the core member 42 of the power transmission device T are in the form of a plate formed of ferrite. The core member 15 of the embodiment is, for example, a laminate formed by stacking five thin-film magnetic sheets each having a thickness of 0.5 mm in the thickness direction. The core member on the power receiving side of the comparative example is, for example, a plate-shaped magnetic body with a thickness of 5 mm. The weight of the core member 15 of the embodiment is, for example, less than half the weight of the core member on the power receiving side of the comparative example (approximately 1 / 2.66).

[0046] like Figure 5 As shown, it can be seen that the KQ product of the embodiment and the comparative example has substantially the same characteristic change.

[0047] As described above, according to the coil unit 10 of the embodiment, the orientation direction D of the core member 15 formed of the directional magnetic material is orthogonal to the direction C along the winding direction of the coil 13, so that the magnetic flux around the coil 13 can be guided to the main magnetic flux. The leakage magnetic flux (magnetic flux other than the main magnetic flux) can be reduced, thereby improving the coupling coefficient. Through the orientation direction D of the core member 15, the increase of iron loss can be suppressed even in a sheet shape, and the so-called Q value can be improved to ensure the desired output.

[0048] The core member 15 is formed, for example, by a stack of thin film magnetic sheets formed from nanocrystalline soft magnetic materials, etc., thereby being able to suppress the occurrence of damage such as cracks or chips, and ensuring the desired output while reducing the weight to less than half, compared to a case where the core member is formed from a plate-shaped magnetic material such as ferrite.

[0049] Since the coil 13 and the core member 15 each have a rectangular ring shape, the orientation direction D of the core member 15 can be easily orthogonal to the direction C along the winding direction of the coil 13 in the straight line portion 13b of the coil 13 and the straight line portion 15b of the core member 15 that face each other, thereby easily achieving a reduction in leakage magnetic flux and an improvement in the coupling coefficient.

[0050] The rectangular ring-shaped core member 15 is formed by combining at least four isosceles trapezoidal members 31 obtained from the belt-shaped member 30 , thereby suppressing a decrease in yield.

[0051] The embodiments of the present invention are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the scope of the main purpose of the invention. These embodiments and their variations are included in the scope and main purpose of the invention, and are also included in the invention described in the technical solution and its equivalent scope.

Claims

1. A coil unit, wherein: The coil unit comprises: a coil that receives AC power transmitted by a non-contact method from a power transmission device; and a core member formed into a sheet shape by a directional magnetic material, and arranged on the rear side of the coil when viewed from the power transmission device when the power transmission device faces the coil; The orientation direction of the core member is orthogonal to the direction along the winding direction of the coil.

2. The coil unit according to claim 1, wherein: The coil and the core member each have a rectangular ring shape. In at least mutually facing linear portions of the coil and the core member, the orientation direction is orthogonal to a direction along the winding direction.

3. The coil unit according to claim 2, wherein: The core member is formed by combining at least four isosceles trapezoidal members having a base angle of 45° obtained by cutting a sheet-like belt-like member.

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