JP6443358B2 - Coil unit - Google Patents

Description

  The present invention relates to a coil unit, and more particularly to a coil unit mounted in a non-contact charging system.

  As disclosed in Patent Documents 1 to 5, a power transmission device that transmits power to a power reception device in a contactless manner and a power reception device that receives power in a contactless manner from the power transmission device are known.

  The power transmission device described in Patent Literature 6 (Japanese Patent Application Laid-Open No. 2008-120239) includes a power transmission side coil unit, and the power reception device includes a power reception side coil unit. Each coil unit includes a coil and a ferrite plate on which the coil is mounted.

JP2013-154815A JP2013-146154A JP2013-146148A JP 2013-110822 A JP 2013-126327 A JP 2008-120239 A

  Generally, a frequency converter is connected to the power transmission coil. The frequency converter includes a plurality of switching elements, and noise is easily included in the transmission power by the switching operation. In the power receiving device, noise included in the transmitted power may be received, and then the noise may be reflected by a device such as a rectifier and radiated from the power receiving coil to the outside.

  Therefore, there is a case where a filter connected to the power transmission coil is connected in the coil unit of the power transmission device, and further a filter connected to the power reception coil is connected in the coil unit of the power reception device.

  The filter includes a core and a filter coil attached to the core. Here, it is conceivable to reduce the size of the apparatus by disposing the filter on the ferrite plate and utilizing the ferrite plate as a part of the filter.

  However, if the ferrite plate is also used as a part of the filter, the amount of magnetic flux flowing through the ferrite plate increases, and the temperature of the ferrite plate increases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a coil unit in which heat dissipation of the ferrite plate is ensured in a coil unit in which a filter is disposed on the ferrite plate. is there.

  A coil unit according to the present invention is formed in a plate shape and includes a ferrite plate including a first main surface and a second main surface arranged in a thickness direction, a coil disposed on the first main surface, and a plate shape A metal plate that is formed and includes a third main surface and a fourth main surface that are arranged in the thickness direction, the third main surface being disposed on the second main surface, and a fourth metal plate And a filter provided on the main surface. The ferrite plate includes a first protrusion and a second protrusion that are formed on the second main surface and protrude in the thickness direction of the ferrite plate. The metal plate is formed with a first slit into which the first protrusion is inserted and a second slit into which the second protrusion is inserted. The filter includes a core and a filter coil attached to the core. The core includes a top plate portion, and a first wall portion and a second wall portion connected to the top plate portion. The first wall portion is disposed in a first projecting portion projecting from the first slit, and the second wall portion is disposed in a second projecting portion projecting from the second slit. The said filter coil is arrange | positioned so that the circumference | surroundings of the said 2nd wall part or the said 2nd protrusion part may be enclosed.

  According to said coil unit, the metal plate is also arrange | positioned between the 1st protrusion part and the 2nd protrusion part, and the heat from a ferrite plate is favorably transmitted to a metal plate, and cools a ferrite plate well. Can do.

  According to the coil unit of the present invention, the heat dissipation of the ferrite plate can be ensured even in the coil unit in which the filter is disposed on the ferrite plate.

1 is a schematic diagram schematically showing a non-contact charging system 1. FIG. 1 is an electric circuit diagram schematically showing a contactless charging system 1. FIG. 1 is an exploded perspective view showing a power receiving device 10. It is sectional drawing in the IV-IV line in FIG. It is a disassembled perspective view which shows the power receiving apparatus 10A of a comparative example. In power receiving device 10A, it is sectional drawing which shows the filter 28A and the surrounding structure. It is a graph which shows the result of the temperature comparison with the coil unit 12 of the power receiving apparatus 10 and the coil unit 12A of the power receiving apparatus 10A in several positions. It is sectional drawing which shows the modification of the coil unit 12 which concerns on embodiment.

  A non-contact charging system 1 according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, the contactless charging system 1 includes a vehicle 2 including a power receiving device 10 and a power storage device 15, and a power transmission device 20 that transmits power to the power receiving device 10 in a contactless manner.

  FIG. 2 is an electric circuit diagram schematically showing the contactless charging system 1. As illustrated in FIG. 2, the power receiving device 10 includes a coil unit 12, a filter 28 connected to the coil unit 12, a rectifier 11 connected to the filter 28, and a power storage device 15 connected to the rectifier 11. .

  The coil unit 12 includes a power receiving coil 16 and a capacitor 17 connected in series to the power receiving coil 16. The filter 28 includes a filter coil 13 connected to the capacitor 17 and a filter coil 14 connected to the power receiving coil 16.

  The power transmission device 20 includes a coil unit 22, a filter 29 connected to the coil unit 22, and a converter 21 connected to the filter 29. The converter 21 is connected to the power source 23. The coil unit 22 includes a power transmission coil 26 and a capacitor 27 connected in series to the power transmission coil 26. Filter 29 includes a filter coil 24 connected to capacitor 27 and a filter coil 25 connected to power transmission coil 26.

  The converter 21 adjusts the frequency and voltage of the AC power supplied from the power source 23 and supplies it to the filter 29. The filter 29 removes AC power noise supplied from the converter 21 and supplies it to the coil unit 22.

  The coil unit 12 receives electric power from the coil unit 22 in a contactless manner. The filter 28 removes noise from the power supplied from the coil unit 12 and supplies it to the rectifier 11. The rectifier 11 converts the supplied AC power into DC power and supplies it to the power storage device 15.

  FIG. 3 is an exploded perspective view showing the power receiving device 10. In FIG. 3, the capacitor 17 and the rectifier 11 are not shown. As illustrated in FIG. 3, the power receiving device 10 includes a coil unit 12, a metal plate 18 disposed on the coil unit 12, a filter 28, and a housing 30.

  The housing 30 accommodates the filter 28, the metal plate 18, the coil unit 12, the rectifier 11 and the capacitor 17 (not shown) inside.

  The housing 30 includes a metal case 31 in which an opening that opens downward is formed, and a resin lid 32 that is provided so as to close the opening of the metal case 31. The metal case 31 is made of a metal such as aluminum.

  The coil unit 12 includes a ferrite plate 33 formed in a plate shape and a power receiving coil 16. The power receiving coil 16 is a hollow spiral coil. The power receiving coil 16 is formed so as to surround the winding axis O2 extending in the vertical direction.

  The ferrite plate 33 is formed in a plate shape, and a hollow portion is formed at the center. Ferrite plate 33 includes a lower surface (first main surface) 35 and an upper surface (second main surface) 36 arranged in the thickness direction. The power receiving coil 16 is disposed on the lower surface 35, and the metal plate 18 and the filter 28 are disposed on the upper surface 36.

  The ferrite plate 33 includes a plurality of divided ferrites 34. The ferrite plate 33 includes a plurality of corner portions 37, and notches 38 are formed in the sides between the corner portions 37. The divided ferrite 34 is formed so as to extend in the radial direction of the power receiving coil 16.

  Of the plurality of divided ferrites 34, one divided ferrite 34A is formed with projecting portions 40, 41, and 42. The protrusions 40, 41, 42 are formed on the upper surface 36, and the protrusions 40, 41, 42 are formed so as to protrude from the upper surface 36 in the thickness direction of the ferrite plate 33.

  The metal plate 18 is formed in a plate shape, and is formed of a metal such as aluminum, for example. The metal plate 18 includes a lower surface (third main surface) 47 and an upper surface (fourth main surface) 48 arranged in the thickness direction of the metal plate 18.

  The metal plate 18 is disposed on the upper surface 36 of the ferrite plate 33, and the lower surface 47 of the metal plate 18 is disposed on the upper surface 36 of the ferrite plate 33.

  The metal plate 18 is larger than the ferrite plate 33, and the ferrite plate 33 is hidden by the metal plate 18 when viewed in plan from above the ferrite plate 33 and the metal plate 18.

  In the metal plate 18, slits 44, 45 and 46 are formed. The protrusions 40, 41, 42 are inserted into the slits 44, 45, 46.

  The filter 28 includes a core 50 and filter coils 13 and 14 attached to the core 50. The core 50 includes a top plate portion 51, and a side wall portion 52 and a side wall portion 54 that are connected to the outer peripheral edge portion of the top plate portion 51 and face each other. The side wall 52 (first wall) and the side wall 54 are arranged in a direction perpendicular to the radial direction of the power receiving coil 16.

  4 is a cross-sectional view taken along line IV-IV in FIG. As shown in FIG. 4, the core 50 includes a central wall portion (second wall portion) 53 that protrudes downward from the lower surface of the top plate portion 51. The central wall portion 53 is disposed between the side wall portion 52 and the side wall portion 54.

  The protruding portion 40 passes through the slit 44 and protrudes above the upper surface 48 of the metal plate 18. Similarly, the protruding portions 41 and 42 pass through the slits 45 and 46 and protrude above the upper surface 48.

  The side wall 52 of the core 50 is disposed on the upper surface of the protrusion 40, and the side wall 54 is disposed on the upper surface of the protrusion 42. The central wall portion 53 is located above the protruding portion 41, and a gap is formed between the lower surface of the central wall portion 53 and the upper surface of the protruding portion 41.

  The filter coil 13 and the filter coil 14 are disposed so as to surround the central wall 53 or the protrusion 41. The filter coils 13 and 14 are spiral coils, and the filter coils 13 and 14 are formed so as to surround a winding axis O3 extending in the vertical direction.

  The metal case 31 includes a top plate portion 55 and partition walls 56 and 57 formed on the lower surface of the top plate portion 55. The filter 28 is disposed in a space formed by the top plate portion 55, the partition wall 56 and the partition wall 57.

  The metal plate 18 is disposed on the upper surface 36, the lower end portion of the partition wall 56 of the metal case 31 is in contact with the upper surface 48 of the metal plate 18, and the lower end portion of the partition wall 57 is also in contact with the upper surface 48. Are arranged.

  When power is transmitted from the power transmitting device 20 to the power receiving device 10 in a contactless manner, AC power is supplied to the coil unit 22, and magnetic flux is generated around the power transmitting coil 26.

  When the magnetic flux is linked to the power transmission coil 26, the coil unit 12 receives power. The AC power received by the coil unit 12 is supplied to the filter 28, and an AC current flows through the filter coils 13 and 14. Thus, an alternating current flows through the power receiving coil 16 and the filter coils 13 and 14 during power reception.

  In FIG. 4, when an alternating current flows through the power receiving coil 16, the magnetic flux MF1 formed around the power receiving coil 16 also flows in the divided ferrite 34A. Further, when an alternating current flows through the filter coils 13 and 14, a magnetic flux MF <b> 2 is also formed around the filter coils 13 and 14.

  The magnetic flux MF1 proceeds mainly in the radial direction of the power receiving coil 16, and in FIG.

  The magnetic flux MF2 is a magnetic path passing through the protruding portion 41, the central wall portion 53, the top plate portion 51, the side wall portion 52, the protruding portion 40, and the protruding portion 41, or the protruding portion 41 and the central wall portion. 53, the top plate part 51, the side wall part 54, the projecting part 42, and the projecting part 41.

  Thus, the magnetic flux MF1 and the magnetic flux MF2 flow through the divided ferrite 34A. In the divided ferrites 34 other than the divided ferrite 34A among the plurality of divided ferrites 34, the magnetic flux MF2 hardly flows.

  Since the amount of magnetic flux flowing in the divided ferrite 34A is large, the iron loss generated in the divided ferrite 34A is larger than the iron loss generated in the other divided ferrite 34. For this reason, the temperature of the divided ferrite 34 </ b> A is likely to be higher than that of the other divided ferrite 34.

  The metal plate 18 is disposed on the upper surface 36 of the divided ferrite 34A. While the metal plate 18 is formed with slits 44, 45, 46, the opening area of the slits 44, 45, 46 is smaller than the installation area of the filter 28.

  The metal plate 18 is also disposed on the portion of the upper surface 36 of the divided ferrite 34 </ b> A located between the protruding portion 41 and the protruding portion 40 and the portion positioned between the protruding portion 41 and the protruding portion 42. .

  For this reason, the contact area between the upper surface 36 of the divided ferrite 34 </ b> A and the lower surface 47 of the metal plate 18 is wide, and the heat of the divided ferrite 34 </ b> A is transmitted to the metal plate 18 satisfactorily. The heat transmitted to the metal plate 18 is transmitted to the metal case 31 through the partition walls 56 and 57.

  The metal case 31 is exposed to the outside, and the heat transmitted to the metal case 31 is radiated to the outside air. When the metal case 31 is disposed on the floor panel of the vehicle 2, heat is also radiated to the floor panel.

  Further, when the power storage device 15 is disposed on the lower surface of the floor panel and the power receiving device 10 is disposed on the lower surface of the power storage device 15, the heat of the metal case 31 is radiated to the power storage device 15.

  Thus, according to the power receiving device 10 according to the present embodiment, the heat of the divided ferrite 34A can be radiated well.

  Next, heat dissipation between the power receiving device 10 according to the present embodiment and the power receiving device 10A according to the comparative example will be compared. FIG. 5 is an exploded perspective view showing a power receiving device 10A of a comparative example. As shown in FIG. 5, in the power receiving device 10 </ b> A, the split ferrite 34 </ b> B is not provided with the protruding portions 40 to 42. Further, a hole 60 is formed in the metal plate 18A in place of the slits 44, 45, 46. The opening area of the hole 60 is larger than the opening area of the slits 44, 45, 46 and the installation area of the filter 28. In the power receiving device 10 </ b> A, the filter 28 </ b> A is inserted into the hole 60.

  FIG. 6 is a cross-sectional view showing the configuration of the filter 28A and its surroundings in the power receiving device 10A. As shown in FIG. 6, the filter 28A includes a core 50A and filter coils 13 and 14 attached to the core 50A.

  The core 50A includes a top plate portion 51A, side wall portions 52A and 54A connected to the side portions of the top plate portion 51A, and a central wall portion 53A formed on the lower surface of the top plate portion 51A. The lower end portions of the side wall portions 52A and 54A are in contact with the upper surface of the divided ferrite 34B.

  While the filter 28A is disposed on the upper surface of the divided ferrite 34B, the hole 60 of the metal plate 18A is located on the upper surface of the divided ferrite 34B. For this reason, the metal plate 18A is not disposed in the portion of the upper surface of the divided ferrite 34B where the filter 28A is disposed.

  Therefore, as shown in FIGS. 3 and 5, the contact area between the metal plate 18 and the divided ferrite 34A is larger than the contact area between the metal plate 18A and the divided ferrite 34B.

  Also in the power receiving device 10A, the magnetic flux MF1 and the magnetic flux MF2 flow through the split ferrite 34B. The heat generated in the split ferrite 34B is transmitted to the metal plate 18A, but the contact area between the split ferrite 34B and the metal plate 18A is small. Therefore, the heat dissipation of the split ferrite 34B is that of the split ferrite 34A of the power receiving device 10. It is worse than heat dissipation.

  FIG. 7 is a graph showing the results of temperature comparison between the coil unit 12 of the power receiving device 10 and the coil unit 12A of the power receiving device 10A at a plurality of positions.

  The vertical axis of the graph shown in FIG. 7 indicates the temperature, and the horizontal axes P1 to P12 indicate the temperature measurement positions. “P3” indicates the temperature of the divided ferrite immediately below the filter. A graph with hatched hatching is the temperature of the coil unit 12A according to the comparative example, and a graph without hatching is the temperature of the coil unit 12 according to the embodiment.

  As is apparent from FIG. 7, the coil unit 12 has a lower temperature than the coil unit 12A at most observation positions, and the coil unit 12A has a lower temperature at the measurement position. It can be seen that there is almost no difference between the temperature and the temperature of the coil unit 12.

  That is, it can be seen that the heat dissipation of the coil unit 12 according to the present embodiment is ensured as compared with the coil unit 12A.

  Here, in FIG. 4, the filter coil 13 is formed so as to surround the periphery of the protruding portion 41, and the filter coil 14 is formed so as to surround the periphery of the central wall portion 53. And the central wall part 53, the side wall part 52, the side wall part 54, the protrusion part 41, the protrusion part 40, and the protrusion part 42 are formed so that it may become substantially symmetrical with respect to a horizontal surface. For this reason, a difference is hardly generated between the inductance of the filter coil 13 and the inductance of the filter coil 14.

  On the other hand, in FIG. 6, the configuration of the divided ferrite 34 </ b> A and the core 50 </ b> A is not symmetrical with respect to the horizontal plane, and a difference is easily generated between the inductances of the filter coil 13 and the filter coil 14. As described above, in the coil unit 12 according to the present embodiment, a difference in inductance between the filter coils 13 and 14 is suppressed.

  In FIG. 4, the protruding portion 41 protrudes upward from the slit 45, and the gap between the central wall portion 53 and the protruding portion 41 is located at the center of the laminated filter coils 13 and 14.

  For example, the vector of the magnetic flux MF2 is directed upward in the process from the lower end of the protrusion 41 toward the upper end of the protrusion 41. And when it radiate | emits from the upper end part of the protrusion part 41, magnetic flux MF2 radiate | emits upwards. Similarly, when the magnetic flux MF2 is emitted from the lower end portion of the central wall portion 53, the magnetic flux MF2 is emitted downward. Thus, in the coil unit 12 according to the present embodiment, the magnetic flux MF2 is prevented from leaking to the surroundings.

  On the other hand, in the example shown in FIG. 6, when the magnetic flux MF2 is emitted from the lower end portion of the central wall portion 53A, it is likely to be emitted so as to spread toward the upper surface of the divided ferrite 34B. For this reason, the magnetic flux MF2 emitted from the lower end portion of the central wall portion 53A is easily interlinked with the filter coil 13.

  As described above, in the coil unit 12 according to the present embodiment, it is easy to ensure the heat dissipation of the divided ferrite 34A, and further, the variation in inductance of the filter coils 13 and 14 and the generation of leakage magnetic flux are suppressed. You can plan.

  In the above embodiment, the example in which the protruding portion 40 and the protruding portion 42 are integrally formed on the upper surface of the divided ferrite 34A has been described. However, the protruding portion 40 and the protruding portion 42 may be separated.

  FIG. 8 is a cross-sectional view showing a modification of the coil unit 12 according to the embodiment. As shown in FIG. 8, in the coil unit 12B according to the modification, the protrusions 40A and 42A are separate from the divided ferrite 34A, and the protrusions 40A and 42A are made of ferrite. In addition, also in this coil unit 12B, the effect | action and effect similar to the coil unit 12 can be acquired.

  In the above embodiment, the coil unit 12 of the power receiving device 10 has been mainly described, but the present invention can also be applied to the coil unit 22 of the power transmitting device 20.

  It should be understood that the embodiments and modifications disclosed this time are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be applied to a coil unit.

DESCRIPTION OF SYMBOLS 1 Non-contact charging system, 2 Vehicle, 10, 10A power receiving device, 11 Rectifier, 12, 12A, 22 Coil unit, 13, 14, 24, 25 Filter coil, 15 Power storage device, 16 Power receiving coil, 17, 27 Capacitor, 18 , 18A Metal plate, 20 Power transmission device, 21 Converter, 23 Power source, 26 Power transmission coil, 28, 28A, 29 Filter, 30 Housing, 31 Metal case, 32 Resin lid, 33 Ferrite plate, 34, 34A, 34B Split ferrite 35, 47 bottom surface, 36, 48 top surface, 37 corners, 38 notches, 40, 41, 42 protrusions, 44, 45, 46 slits, 50, 50A core, 51, 51A, 55 top plate portion, 52, 52A, 54, 54A Side wall part, 53, 53A Central wall part, 56, 57 Partition wall, 60 hole part.

Claims (1)

A ferrite plate formed in a plate shape and including a first main surface and a second main surface arranged in the thickness direction;
A coil disposed on the first main surface;
A metal plate that is formed in a plate shape and includes a third main surface and a fourth main surface that are arranged in the thickness direction, and the third main surface is disposed on the second main surface;
A filter provided on the fourth main surface of the metal plate;
With
The ferrite plate includes a first protrusion and a second protrusion that are formed on the second main surface and protrude in the thickness direction of the ferrite plate,
The metal plate is formed with a first slit into which the first protrusion is inserted and a second slit into which the second protrusion is inserted,
The filter includes a core and a filter coil attached to the core,
The core includes a top plate portion, a first wall portion and a second wall portion connected to the top plate portion,
The first wall portion is disposed in the first projecting portion projecting from the first slit, and the second wall portion is disposed in the second projecting portion projecting from the second slit,
The said filter coil is a coil unit arrange | positioned so that the circumference | surroundings of the said 2nd wall part or the said 2nd protrusion part may be enclosed.

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