Coil Unit

Abstract

To provide a coil unit capable of improving a cooling efficiency while suppressing an increase in weight.SOLUTION: A coil unit for a vehicle, comprises: a housing body 11; a coil 13 that receives an AC power transmitted in a non-contact manner from a power transmission device T; and a support member 31. The housing 11 includes a front surface 11A which is exposed to an external part below a vehicle body and in which a groove 11a along a flow direction of wind received at traveling is formed. The coil 13 arranged inside the housing body 11 comes into direct contact with the housing body 11 via a heat radiation member 11b provided at an internal surface 11B of the housing body 11. The support member 31 comes into contact with the internal surface 11B of the housing body 11 and the heat radiation member 11b, and covers the front surface of the coil 13. A width of the support member 31 in an orthogonal direction to a projection direction of the heat radiation member 11b is changed to an increase inclination as directing toward the internal surface 11B from a tip end side of the heat radiation member 11b along the projection direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In recent years, research and development has been conducted into charging vehicles equipped with secondary batteries that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy. Conventionally, in a contactless power transfer system that supplies power from outside the vehicle to the vehicle by contactless power transfer, a device is known in which each coil for transmitting and receiving power is covered with a thermally conductive resin to ensure mechanical strength and heat dissipation (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-87733 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology for charging and supplying power to a vehicle equipped with a secondary battery, it is desirable to suppress an increase in weight while ensuring cooling of the coil unit on the vehicle side. In the non-contact power supply device of the above-mentioned conventional technology, it is desirable to improve the cooling efficiency by reducing the thermal resistance of the housing against the coil and heat-generating components, without requiring a configuration that increases the weight of a cooling device, for example.

[0005] An object of the present invention is to provide a coil unit capable of improving cooling efficiency while suppressing an increase in weight, which in turn contributes to improving energy efficiency. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above object, the present invention employs the following aspects. (1): A coil unit according to one aspect of the present invention (e.g., coil unit 10 in the embodiments) includes a housing (e.g., housing 11 in the embodiments) having a surface (e.g., surface 11A in the embodiments) exposed to the outside under the vehicle body, a heat dissipation member (e.g., heat dissipation member 11b in the embodiments) protruding inward from an inner surface (e.g., inner surface 11B in the embodiments) of the housing on the back side opposite the surface of the housing, a coil (e.g., coil 13 in the embodiments) that is disposed inside the housing and receives AC power transmitted contactlessly from a power transmission device (e.g., power transmission device T in the embodiments), and a support member (e.g., support member 31 in the embodiments) that contacts the inner surface of the housing and the heat dissipation member and covers at least a portion of the surface of the coil, and the width of the support member in a direction perpendicular to the protruding direction of the heat dissipation member tends to increase as it moves from the tip side of the heat dissipation member toward the inner surface along the protruding direction.

[0007] (2) In the coil unit described in (1) above, the support member may be made of a material having predetermined electrical insulation properties and thermal conductivity.

[0008] (3): In the coil unit described in (2) above, the thickness of the support member covering the tip surface of the coil in the protruding direction (e.g., tip surface 13A in the embodiment) may be set in accordance with the electrical insulation, and the thickness of the support member covering the surface opposite the heat dissipation member side of the coil in the orthogonal direction (e.g., end surface 13B in the embodiment) may be set in accordance with the thermal conductivity.

[0009] (4): In the coil unit described in any one of (1) to (3) above, the housing may have a surface on which a groove (e.g., groove 11a in the embodiment) is formed along the direction of the wind flow received during driving. Effect of the Invention

[0010] According to the above (1), the width of the support member increases from the tip of the heat dissipation member toward the inner surface of the housing along the protruding direction, thereby increasing the amount of heat transfer on the inner surface side and improving the cooling efficiency. For example, compared to when the width of the support member is constant along the protruding direction, the weight and volume of the support member can be prevented from increasing.

[0011] In the above case of (2), the supporting member has a predetermined electrical insulation property and thermal conductivity for the heat-generating coil, so that the desired withstand voltage and heat dissipation property can be ensured.

[0012] In the above case (3), it is possible to ensure the desired voltage resistance and heat dissipation properties while suppressing an increase in the weight and volume of the support member.

[0013] In the case of (4) above, the coil can be cooled from the surface of the housing by the groove that efficiently guides the wind while the vehicle is moving. The coil comes into contact with the housing via the support member, thereby reducing thermal resistance and improving cooling efficiency. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is an exploded perspective view showing a configuration of a coil unit according to an embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view of the coil unit according to the embodiment of the present invention, taken along the ZX plane at the position of line AA shown in FIG. 1. [Diagram 3] FIG. 2 is an enlarged view showing a coil and a housing in the coil unit according to the embodiment of the present invention. [Figure 4] 6A to 6C are diagrams showing a process of integrating a coil and a housing in a coil unit according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a coil unit according to an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is an exploded perspective view showing the configuration of a coil unit 10 according to an embodiment. Fig. 2 is a cross-sectional view of the coil unit 10 according to the embodiment taken along the ZX plane at the position of line AA shown in Fig. 1. In the following, the directions of the X-axis, Y-axis, and Z-axis, which are mutually orthogonal in a three-dimensional space, are parallel to each other. For example, as shown in Fig. 1 and Fig. 2, the Z-axis direction is parallel to the up-down direction of a moving body such as a vehicle on which the coil unit 10 is mounted, 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 forward direction of the moving body, and the positive direction of the Y-axis is the rightward direction of the moving body.

[0016] The coil unit 10 of the embodiment is mounted on, for example, a vehicle that receives electric power from the outside through contactless power transmission. The vehicle is, for example, an electric vehicle such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle. The coil unit 10 is fixed, for example, to the lower part of a frame-shaped subframe provided on the lower part of the vehicle body. The coil unit 10 constitutes a part of a power receiving device that receives AC power from an external power transmitting device T through contactless power transmission. As shown in FIGS. 1 and 2, the coil unit 10 includes, for example, a housing 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.

[0017] The outer shape of the housing 11 is formed, for example, in a rectangular frame shape. The housing 11 is formed, for example, from a material such as resin having a predetermined thermal conductivity. The housing 11 includes, for example, a first housing section 21 and a second housing section 22. The first housing section 21 includes a coil 13, an insulating member 14, and a core member 15, which will be described later. The second housing section 22 includes boards 23, 26, and 27, a capacitor 24, and a semiconductor element 28, which will be described later. The first housing section 21 is provided, for example, so as to surround the lower side in the vertical direction and the inner side and the outer side in the direction perpendicular to the vertical direction with respect to the coil 13, the insulating member 14, and the core member 15, which will be described later. The second housing section 22 is provided, for example, behind the first housing section 21 in the front-rear direction. The second housing section 22 is provided, for example, so as to surround the lower side in the vertical direction and the outer side in the direction perpendicular to the vertical direction with respect to the boards 23, 26, and 27, the capacitor 24, and the semiconductor element 28, which will be described later.

[0018] The housing 11 has a surface 11A on which, for example, a plurality of grooves 11a are formed. The surface 11A of the housing 11 (i.e., the lower surface, which is the surface on the lower side in the up-down direction) is exposed to the outside below the vehicle body. The plurality of grooves 11a are formed, for example, along the front-rear direction so as to be aligned with the flow direction of the wind (traveling wind) received while the vehicle is traveling. The housing 11 includes, for example, a plurality of heat dissipation members 11b protruding inward from an inner surface 11B on the rear side opposite to the front surface 11A. The outer shape of the heat dissipation members 11b is, for example, a plate-like fin type. The plurality of heat dissipation members 11b contact the coil 13.

[0019] The outer shape of the first cover 12 is formed, for example, in the shape of a rectangular plate with through holes 12a formed in the thickness direction. The first cover 12 is provided, for example, so as to surround the upper side in the vertical direction of the coil 13, the insulating member 14, and the core member 15 described below. The first cover 12 forms an accommodation space between itself and an inner surface 11B of the housing 11 in which the coil 13, the insulating member 14, and the core member 15 are accommodated. The first cover 12 closes an open end of a first accommodation section 21 of the housing 11 in which the coil 13, the insulating member 14, and the core member 15 are accommodated.

[0020] The outer shape of coil 13 is formed, for example, in a rectangular spiral shape along inner surface 11B of housing 11. Coil 13 is disposed, for example, on the upper side of inner surface 11B. The wire of coil 13 is in direct contact with a plurality of heat dissipation members 11b. The insulating member 14 has an outer shape of, for example, a rectangular sheet with through holes 14a formed in the thickness direction. The insulating member 14 is made of an electrically insulating material. The insulating member 14 is disposed above the coil 13, for example. The outer shape of the core member 15 is formed, for example, in a rectangular plate shape with through holes 15a formed in the thickness direction. The core member 15 is formed of a magnetic material with relatively high 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. The core member 15 is disposed, for example, above the insulating member 14.

[0021] The outer shape of the back member 16 is, for example, a rectangular plate with a through hole formed in the thickness direction. The outer shape of the inner member 17 is, for example, a box shape with a rectangular frame-shaped wall and a lid that closes the lower open end of the wall. The inner member 17 protrudes downward in the up-down direction, for example, from the peripheral edge surrounding the through hole of the back member 16. The back member 16 and the inner member 17 are integrally formed from a magnetic material with a relatively high magnetic permeability, for example, an electromagnetic steel plate such as a silicon steel plate.

[0022] The back member 16 is disposed, for example, on the upper side in the up-down direction with respect to the first cover 12. The inner member 17 is inserted, for example, into the through holes 12a, 15a, 14a of the first cover 12, the core member 15, and the insulating member 14, the hollow-core region 13a of the coil 13, and the through hole 11c in the thickness direction of the housing 11. The inner member 17 protrudes downward from the surface 11A of the housing 11, for example.

[0023] The outer shape of second cover 18 is formed, for example, into a hipped roof type. Between second cover 18 and inner surface 11B of housing 11, an accommodation space is formed in which each of substrates 23, 26, 27, capacitor 24, and semiconductor element 28 are accommodated. Second cover 18 closes the open end of second accommodation section 22 of housing 11 in which each of substrates 23, 26, 27, capacitor 24, and semiconductor element 28 are accommodated.

[0024] The capacitor substrate 23 has a plurality of capacitors 24, such as film capacitors, fixed thereto. The capacitors 24 are, for example, resonance capacitors (condensers) connected to the coil 13. The plurality of capacitors 24 are fixed to the capacitor substrate 23 and are in contact with the inner surface 11B of the housing 11 via a thermally conductive material 25, such as a thermal compound.

[0025] The control board 26 is disposed, for example, above the capacitor board 23. The control board 26 controls, for example, power conversion of the power receiving device and communication with an external power transmitting device T. The control board 26 is a software function unit that functions when a processor such as a CPU (Central Processing Unit) executes a predetermined program. The software function unit is an ECU (Electronic Control Unit) that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. At least a part of the control board 26 may be an integrated circuit such as an LSI (Large Scale Integration). The control board 26 generates a control signal to be input to the gate drive board 27 in accordance with, for example, a target output of the power receiving device. The control signal is, for example, a signal indicating the timing to turn on (conductive) / off (cutoff) a plurality of switching elements constituting a power conversion unit of the power receiving device. For example, the control signal is a pulse-width modulated signal.

[0026] The gate drive board 27 is disposed, for example, above the control board 26. The gate drive board 27 is connected to the gates of a plurality of switching elements constituting a power conversion unit of the power receiving device, and includes, for example, an integrated circuit and a plurality of gate resistors. The gate drive board 27 generates gate signals for actually driving each switching element to turn on (conductive) / off (cut-off) based on the control signals received from the control board 26. For example, the gate drive board 27 performs amplification and level shifting of the control signals to generate the gate signals.

[0027] The semiconductor elements 28 are, for example, switching elements and rectifying elements constituting a power conversion unit of the power receiving device. The switching elements are, for example, transistors such as SiC (Silicon Carbide) MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The rectifying elements are, for example, free wheel diodes connected in parallel to each transistor. The multiple semiconductor elements 28 are, for example, fixed to the upper part of the gate drive substrate 27 and disposed between the gate drive substrate 27 and the inner surface 18A of the second cover 18. The second cover 18 includes a heat sink 29 disposed on an outer surface (front surface) 18B opposite to the inner surface 18A. The heat sink 29 is, for example, a heat sink including a plurality of fin members protruding outward.

[0028] In the coil unit 10, the coil 13, the insulating member 14, and the core member 15 are arranged in the first housing portion 21 of the housing 11 while being stacked in order in the vertical direction. FIG. 3 is an enlarged view of the coil 13 and the housing 11 in the coil unit 10 of the embodiment. As shown in FIG. 3, the coil 13 is fixed to the heat dissipation member 11b of the housing 11 via, for example, a support member 31. The support member 31 is formed of, for example, a material such as a resin having predetermined electrical insulation and thermal conductivity. Examples of the predetermined material include polyarylate (PAR), polyphenylene sulfide (PPS), polyurethane (PU), and the like. The dielectric breakdown voltage of the predetermined material is, for example, about 10 to 20 kV / mm. The thermal conductivity of the predetermined material is, for example, about 0.2 to 4 W / mK. The support member 31 is formed of a material such as a thermosetting resin by a process such as so-called potting, such as vacuum casting, or injection molding.

[0029] FIG. 4 is a diagram showing a process (potting process) of integrating the coil 13 and the housing 11 in the coil unit 10 of the embodiment. As shown in FIG. 4, first, the spiral coil 13 is inserted between a plurality of heat dissipation members 11b inside the housing 11, and is disposed so as to be spaced a predetermined distance from the inner surface 11B and each of the heat dissipation members 11b (step S01). Next, the multiple cores 32 are inserted between the multiple heat dissipation members 11b and arranged at a predetermined distance from the coil 13 (step S02). The shape of each core 32 is formed according to the shape of the support member 31 described later. Next, a material such as a thermosetting resin is injected by so-called potting into the inner surface 11B of the housing 11 and the spaces around the coil 13 formed by the heat dissipation members 11b and the cores 32 (step S03). Next, each core 32 is removed from inside the housing 11 after the material, such as a thermosetting resin, injected into the space around the coil 13 is hardened to form the support member 31 (step S04).

[0030] As shown in FIG. 3, the outer shape of the support member 31 covering the coil 13 has a shape in which, for example, the thickness in a direction perpendicular to the protruding direction tends to increase as the heat dissipation members 11b protrude from the inner surface 11B of the housing 11 in a direction (Z-axis direction) along the protruding direction. The outer shape of the support member 31 is a shape determined by, for example, a first thickness Wa and a second thickness Wb. The first thickness Wa is set, for example, according to the electrical insulation of the support member 31, and is a thickness (for example, several mm, etc.) required to ensure a predetermined electrical insulation (for example, a dielectric strength voltage of several tens of kV, etc.). The second thickness Wb is set, for example, according to the thermal conductivity of the support member 31, and is a thickness required to ensure a predetermined thermal conductivity (for example, a heat transfer amount, etc.).

[0031] The first thickness Wa is, for example, the thickness of a portion covering the tip end surface 13A of the coil 13 on the tip side of the heat dissipation member 11b in the direction along the protruding direction (Z-axis direction). The second thickness Wb is, for example, the thickness of a portion from the surface (end surface 13B) opposite the heat dissipation member 11b side of the coil 13 in a direction perpendicular to the protruding direction (for example, the X-axis direction) to the end of the support member 31, that is, the thickness of the portion covering the end surface 13B of the coil 13, among the portion in contact with the inner surface 11B of the housing 11.

[0032] In the support member 31, the thickness of the portion between the coil 13 and the heat dissipation member 11b and the portion between the coil 13 and the inner surface 11B is a constant thickness such as a first thickness Wa. In the support member 31, the thickness of the portion covering the end face 13B of the coil 13 in the perpendicular direction tends to increase from a first thickness Wa, etc. to a second thickness Wb, for example, as it moves from the tip side of the heat dissipation member 11b toward the inner surface 11B in a direction along the protrusion direction (Z-axis direction).

[0033] As described above, according to the coil unit 10 of the embodiment, the width of the support member 31 in the direction perpendicular to the protruding direction tends to increase as it moves from the tip side of the heat dissipation member 11b toward the inner surface 11B of the housing 11 along the protruding direction, thereby increasing the amount of heat transfer on the inner surface 11B side and improving the cooling efficiency. Since the second thickness Wb is set on the inner surface 11B side, where the amount of heat transfer is relatively large, it is possible to suppress an increase in the weight and volume of the support member 31 while ensuring the desired thermal conductivity, compared to, for example, a case where a constant thickness such as the second thickness Wb is set along the protrusion direction.

[0034] The supporting member 31 has a predetermined electrical insulation property and thermal conductivity for the heat-generating coil 13, so that the desired voltage resistance and heat dissipation property can be ensured. It is possible to prevent the weight and volume of the support member 31 from increasing, while ensuring the desired voltage resistance and heat dissipation properties.

[0035] Groove 11a efficiently guides the wind generated when the vehicle is moving, allowing coil 13 to be cooled from surface 11A of housing 11. Coil 13 comes into contact with housing 11 via support member 31, thereby reducing thermal resistance and improving cooling efficiency.

[0036] (Modification) In the above-described embodiment, the support member 31 is formed by vacuum casting using a thermosetting resin as a material, but this is not limited to this, and the support member 31 may be formed by other processes such as injection molding and by materials other than thermosetting resin.

[0037] The embodiments of the present invention are presented 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 modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as the scope and spirit of the invention. [Explanation of symbols]

[0038] 10...coil unit, 11...housing, 11a...groove, 11c...through hole, 12...first cover, 12a...through hole, 13...coil, 13a...air-core region, 14...insulating member, 14a...through hole, 15...core member, 15a...through hole, 16...back member, 17...inner member, 18...second cover, 23...capacitor board, 24...capacitor, 25...thermal conductive material, 26...control board, 27...gate drive board, 28...semiconductor element, 29...heat sink, 31...support member, T...power transmission device.

Claims

1. A housing having a surface exposed to the outside under a vehicle body; a heat dissipation member protruding inward from an inner surface on a back side of the housing relative to the front surface; a coil that is disposed inside the housing and receives AC power transmitted from a power transmitting device in a non-contact manner; a support member that contacts the inner surface of the housing and the heat dissipation member and covers at least a portion of a surface of the coil; Equipped with The width of the support member in a direction perpendicular to the protruding direction of the heat dissipating member increases from the tip side of the heat dissipating member toward the inner surface along the protruding direction. Coil unit.

2. The support member is made of a material having a predetermined electrical insulation property and thermal conductivity. The coil unit according to claim 1 .

3. a thickness of the support member covering the tip surface of the coil in the protruding direction is set according to the electrical insulation property, The thickness of the support member covering the surface of the coil opposite to the heat dissipation member in the orthogonal direction is set according to the thermal conductivity. The coil unit according to claim 2 .

4. The housing has a surface on which grooves are formed along the direction of wind flow received during driving. The coil unit according to any one of claims 1 to 3.

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