JP2014197586A - Antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna for a power transmission system capable of improving transmission efficiency without heating a vehicle bottom part.SOLUTION: An antenna comprises: a first substrate; a second substrate; a main coil composed of a conductor wire wound around a first axis so as to be locked to the first substrate; a plurality of sub coils composed of conductor wires wound around a plurality of second axes included in a plane whose normal line is the first axis so as to be locked to the second substrate; and a third substrate 600 sandwiched and held by the main coil and the plurality of sub coils. The plurality of sub coils are connected in series and the main coil is also connected in series to the series connection of the sub coils.

Description

  The present invention relates to an antenna that is used in a magnetic resonance wireless power transmission system and receives power or transmits power.

  In recent years, development of technology for transmitting electric power (electric energy) wirelessly without using a power cord or the like has become active. Among wireless transmission methods, there is a technique called magnetic resonance as a technology that has attracted particular attention. This magnetic resonance method was proposed by a research group of Massachusetts Institute of Technology in 2007, and a technology related to this is disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-501510.

  The magnetic resonance type wireless power transmission system uses an antenna having the same resonance frequency of the power transmission side antenna as that of the power reception side antenna and a high Q value (100 or more), so that the power transmission side antenna is changed to the power reception side antenna. On the other hand, energy transmission is performed efficiently, and one of the major features is that the power transmission distance can be several tens of centimeters to several meters.

Some proposals have been made on the specific configuration of the antenna used in the above-described magnetic resonance type wireless power transmission system. For example, Patent Document 2 (Japanese Patent Application Laid-Open No. 2010-73976) discloses a structure of a communication coil provided in each of the power feeding circuit and the power receiving circuit of a wireless power transmission apparatus that wirelessly transmits power from the power feeding circuit to the power receiving circuit. A printed circuit board made of a material having a relative dielectric constant greater than 1, a primary coil provided on the first layer of the printed circuit board and formed of a conductive pattern forming at least one loop, and a second layer of the printed circuit board And a resonance coil formed of a conductive pattern having a spiral shape. The communication coil structure of the wireless power transmission device is disclosed.
Special table 2009-501510 JP 2010-73976 A

  When the magnetic resonance type power transmission system as described above is used for power supply to vehicles such as an electric vehicle (EV) and a hybrid electric vehicle (HEV), a power transmission antenna is embedded in the ground and receives power. It is assumed that the antenna for use is laid out on the bottom of the vehicle.

  However, when the antenna having the structure described in Patent Document 1 is installed at the bottom of a vehicle made of a metal body, a magnetic field leaked from the antenna during power transmission enters the metal body, and current is induced in the metal body by the magnetic field. There was a problem of heating the bottom of the vehicle.

  Another problem is that the power transmission efficiency of the system is suppressed by the magnetic field that leaks from the antenna and enters the metal body during power transmission.

In order to solve the above problem, an antenna according to the present invention includes a first base material, a second base material, and a first base material.
A main coil composed of a conductor wire wound around the axis and locked to the first base material, and a plurality of second axes included in a plane having the first axis as a normal line And a third base material sandwiched between the plurality of sub-coils, the main coil, and the plurality of sub-coils, and being engaged with the second base material. The plurality of subcoils are connected in series, and the main coil is further connected in series to the series connection of the plurality of subcoils.

  The antenna according to the present invention is characterized in that a conductor constituting the main coil is spiral in the plane.

  Further, the antenna according to the present invention is characterized in that a magnetic core is disposed on the inner peripheral side of the conductor constituting the sub-coil by turning around.

  The antenna according to the present invention is characterized in that a material having a small dielectric loss tangent and high insulation is used for the third base material.

  In the antenna according to the present invention, any one of polycarbonate, polypropylene, and polytetrafluoroethylene is used as the third base material.

  The antenna according to the present invention is an antenna that has a main coil and a plurality of subcoils, and corrects the magnetic field generated by the main coil with the magnetic fields generated by the plurality of subcoils. According to the antenna according to the present invention, Even when the antenna is mounted on the bottom of the vehicle, the magnetic field generated by the entire antenna is directional, so it is possible to reduce the magnetic field that leaks from the antenna during power transmission and enters the metal body at the bottom of the vehicle. The bottom is not heated, and in addition, the power transmission efficiency of the system can be improved.

1 is a block diagram of a power transmission system in which an antenna according to an embodiment of the present invention is used. It is a figure which shows the inverter part of an electric power transmission system. It is a figure which shows the base material 300 utilized in order to model the coil of the antenna which concerns on embodiment of this invention. 4 is a diagram schematically showing an outline of a main coil formed on a base material 300. FIG. 4 is a diagram schematically showing an outline of a subcoil formed on a base material 300. FIG. It is a figure which shows an example of the pattern at the time of winding the conductor wire 400 around the base material 300. FIG. It is a figure which shows the antenna which concerns on embodiment of this invention. It is a figure explaining the meaning which provides the protrusion 320 for main coil modeling. It is a figure which shows the antenna which concerns on other embodiment of this invention. It is a figure which shows the antenna which concerns on other embodiment of this invention. It is a figure which shows the antenna which concerns on other embodiment of this invention. It is a figure which shows the equivalent circuit of the antenna which concerns on other embodiment of this invention. It is a figure which shows the base material 300 utilized in order to model the coil of the antenna which concerns on other embodiment of this invention. It is a figure explaining attachment of the 2nd substrate 500 in an antenna concerning other embodiments of the present invention. It is a figure which shows an example of the pattern at the time of winding the conductor wire 400 around the base material 300. FIG. It is a disassembled perspective view of the antenna which concerns on other embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a power transmission system in which an antenna according to an embodiment of the present invention is used. The antenna according to the present invention can be applied to both a power receiving antenna and a power transmitting antenna constituting the power transmission system. However, in the following embodiments, the antenna of the present invention is used as the power receiving antenna. The applied example will be described.

  As a power transmission system using the antenna of the present invention, for example, a system for charging a vehicle such as an electric vehicle (EV) or a hybrid electric vehicle (HEV) is assumed. Since the electric power transmission system transmits electric power to the vehicle as described above in a non-contact manner, the electric power transmission system is provided in a stop space where the vehicle can be stopped. The stop space, which is a vehicle charging space, is configured such that the power transmission antenna 105 and the like are buried in the ground. A user of the vehicle stops the vehicle in a stop space where the power transmission system is provided, and makes the power reception antenna 201 mounted on the vehicle and the power transmission antenna 105 face each other to thereby generate power from the power transmission system. Receive power. When the vehicle is stopped in the stop space, the power receiving antenna 201 mounted on the vehicle has a positional relationship with the highest transmission efficiency with respect to the power transmission antenna 105.

  In the power transmission system, when power is efficiently transmitted from the power transmission antenna 105 on the power transmission system 100 side to the power reception antenna 201 on the power reception side system 200 side, the resonance frequency of the power transmission antenna 105 and the resonance frequency of the power reception antenna 201 are By making the same, energy transmission is efficiently performed from the power transmission side antenna to the power reception side antenna.

  The AC / DC conversion unit 101 in the power transmission system 100 is a converter that converts an input commercial power source into a constant direct current. The output from the AC / DC converter 101 is boosted to a predetermined voltage in the high voltage generator 102. Setting of the voltage generated by the voltage adjustment unit 102 can be controlled from the main control unit 110.

The inverter unit 103 generates a predetermined AC voltage from the high voltage supplied from the high voltage generation unit 102 and inputs it to the matching unit 104. FIG. 2 is a diagram illustrating an inverter unit of the power transmission system. For example, as shown in FIG. 2, the inverter unit 103 includes four field effect transistors (FETs) composed of Q _{A to} Q _D connected in a full bridge system.

In the present embodiment, between the connection portion T1 between the switching elements Q _A and Q _B connected in series and the connection portion T2 between the switching elements Q _C and Q _D connected in series. The matching device 104 is connected to the switching element Q _A.
When the switching element Q _D is on, the switching element Q _B and the switching element Q _C are off. When the switching element Q _B and the switching element Q _C are on, the switching element Q _A and the switching element Q _D are off. As a result, a rectangular wave AC voltage is generated between the connection portion T1 and the connection portion T2. In the present embodiment, the range of the frequency of the rectangular wave generated by the switching of each switching element is about 20 kHz to several 1000 kHz.

Drive signals for the switching elements Q _{A to} Q _D constituting the inverter unit 103 as described above are input from the main control unit 110. The frequency for driving the inverter unit 103 can be controlled from the main control unit 110.

The matching unit 104 is composed of passive elements having a predetermined circuit constant, and the inverter unit 10
The output from 3 is input. The output from the matching unit 104 is supplied to the power transmission antenna 105. The circuit constants of the passive elements constituting the matching unit 104 can be adjusted based on a command from the main control unit 110. The main control unit 110 instructs the matching unit 104 so that the power transmitting antenna 105 and the power receiving antenna 201 resonate.

  The power transmission antenna 105 is composed of a coil having an inductive reactance component, and resonates with the vehicle-mounted power reception antenna 201 arranged so as to face each other, so that the electric energy output from the power transmission antenna 105 is received by the power reception antenna. 201 can be sent.

  The main control unit 110 of the power transmission system 100 is a general-purpose information processing unit that includes a CPU, a ROM that holds a program that runs on the CPU, and a RAM that is a work area of the CPU. The main control unit 110 operates in cooperation with the components connected to the main control unit 110 shown in the figure.

  The communication unit 120 is configured to perform wireless communication with the vehicle-side communication unit 220 so that data can be transmitted to and received from the vehicle. Data received by the communication unit 120 is transferred to the main control unit 110, and the main control unit 110 can transmit predetermined information to the vehicle side via the communication unit 120.

  Next, a configuration provided on the vehicle side will be described. In the system on the power receiving side of the vehicle, the power receiving antenna 201 receives electric energy output from the power transmitting antenna 105 by resonating with the power transmitting antenna 105. Such a power receiving antenna 201 is adapted to be attached to the bottom portion of the vehicle.

  The AC power received by the power receiving antenna 201 is rectified by the rectification unit 202, and the rectified power is stored in the battery 204 through the charge control unit 203. The charging control unit 203 controls the storage of the battery 204 based on a command from the main control unit 210. In addition, the charging control unit 203 is configured to perform the remaining amount management of the battery 204 and the like.

  The main control unit 210 is a general-purpose information processing unit that includes a CPU, a ROM that holds programs that run on the CPU, and a RAM that is a work area of the CPU. The main controller 210 operates in cooperation with the components connected to the main controller 210 shown in the figure.

  The interface unit 230 is provided in the driver's seat of the vehicle and provides predetermined information to the user (driver) or accepts operation / input from the user. A touch panel, a speaker, and the like. When a predetermined operation by the user is executed, it is sent as operation data from the interface unit 230 to the main control unit 210 and processed. Further, when providing predetermined information to the user, display instruction data for displaying the predetermined information is transmitted from the main control unit 210 to the interface unit 230.

  Further, the vehicle-side communication unit 220 is configured to perform wireless communication with the power transmission-side communication unit 120 and to transmit and receive data to and from the power transmission-side system. Data received by the communication unit 220 is transferred to the main control unit 210, and the main control unit 210 can transmit predetermined information to the power transmission system side via the communication unit 220.

In the power transmission system, a user who wants to receive power inputs the information indicating that charging is performed from the interface unit 230 by stopping the vehicle in the stop space where the power transmission side system as described above is provided. Receiving this, the main control unit 210 obtains the remaining amount of the battery 204 from the charge control unit 203 and calculates the amount of power necessary for charging the battery 204. The calculated amount of power and information to request power transmission are transmitted from the vehicle side communication unit 220 to the communication unit 120 of the power transmission side system. The main control unit 110 of the power transmission side system that has received the information controls the high voltage generation unit 102, the inverter unit 103, and the matching unit 104 to transmit power to the vehicle side.

  Next, a specific configuration of the antenna used in the power transmission system 100 configured as described above will be described. Hereinafter, the antenna of the present invention can be applied to both the power transmitting antenna 105 and the power receiving antenna 201.

  In the following embodiments, the configuration related to the coil constituting the antenna will be described in detail. However, the antenna that performs power transmission by the magnetic resonance method is not limited to the inductance component of the coil, the capacitance component based on the floating capacity, or It also includes a capacitance component based on an intentionally added capacitor.

  The antenna according to the present invention is an antenna including a main coil MC and a plurality of subcoils SC, and has directivity as an antenna by correcting a magnetic field generated by the main coil MC with a magnetic field generated by the plurality of subcoils SC. It comes to let you.

  First, the structure of the base material 300 used for modeling the coil which comprises an antenna is demonstrated. FIG. 3 is a view showing a base material 300 used for modeling an antenna coil according to an embodiment of the present invention. In the present embodiment, the substrate 300 is described as an example of a substantially circular shape, but is not limited thereto.

  The base material 300 is a substrate-like member having a first surface 301 and a second surface 302 that has a front and back relationship with the first surface 301. For example, the base material 300 can be configured using a material having a small dielectric loss tangent such as polycarbonate or polypropylene. preferable.

  The base material 300 includes a base portion 310 that forms a substantially circular flat plate portion, and a plurality of projecting pieces that extend radially from the base portion 310.

  As these protrusions, there are two types of protrusions 320 for main coil formation and protrusions 330 for subcoil formation. The main coil formation protrusions 320 and the subcoil formation protrusions 330 are alternately arranged around the base 310. To be arranged. In the present embodiment, one main coil shaping protrusion 320 and one sub-coil shaping protrusion 330 are described as an example in which they are alternately arranged around the base 310. Not limited to this example, for example, as shown in FIG. 15 to be described later, an arbitrary number of continuous main coil shaping protrusions 320 and one sub-coil shaping protrusion 330 are alternately formed on the base 310. On the contrary, one main coil shaping protrusion 320 and an arbitrary continuous number of sub-coil shaping protrusions 330 are alternately arranged around the base 310. The present invention also relates to a configuration, and further, a configuration in which an arbitrary number of continuous main coil modeling protrusions 320 and an arbitrary number of continuous sub coil modeling protrusions 330 are alternately arranged around the base 310. Included in category Is shall.

  The main coil shaping protrusion 320 has two side portions 322 substantially parallel to a direction extending radially from the base portion 310, and an edge portion 325 corresponding to the outer edge of the substrate 300. Further, the sub-coil shaping projection piece 330 also has two side portions 332 substantially parallel to the direction extending radially from the base portion 310, and an edge portion 335 corresponding to the outer edge of the substrate 300.

  The main coil shaping protrusion 320 is used to pass the conductor wire 400 on one side of the first surface 301 or the second surface 302 and to lock the conductor wire 400. Thereby, the shape of the main coil MC is maintained by the conductor wire 400. The sub-coil shaping projection piece 330 is used for winding the conductor wire 400, whereby the shape of the sub-coil SC is maintained by the conductor wire 400. Further, a part of the conductor wire 400 wound by the sub-coil shaping projection piece 330 and the conductor wire 400 locked by the sub-coil shaping projection piece 330 also function as the main coil MC.

  An outline of the main coil MC and the subcoil SC formed of the conductor wire 400 using the base material 300 as described above will be described. FIG. 4 is a diagram schematically showing the outline of the main coil MC formed on the base material 300, and FIG. 5 is a diagram schematically showing the outline of the subcoil SC formed on the base material 300.

4 and 5, the plane P is a plane including the first surface 301 of the substrate 300, and the first axis is a normal line of the plane P. The second axis is an axis included in the plane P.

  The main coil MC can be defined as a conductor formed around the first axis.

In the example of FIG. 4, the main coil MC is configured by a spiral conductor in the plane P with the first axis as the center, but the main coil MC is a conductor that circulates around the first axis. As long as it is formed by, what kind of thing may be sufficient. For example, the main coil MC may be a solenoidal coil wound around the first axis. In addition, as the conductive portion of the main coil MC, it is possible to use a conductor printed on the base material 300 instead of a conductor wire.

In the main coil MC configured as described above, a magnetic field Hm having a direction as shown in FIG. 4 is formed by the current I flowing at a certain instant t.

  On the other hand, the subcoil SC can be defined as a conductor formed around the second axis.

  FIG. 5 shows an example in which the subcoil SC is formed by a solenoidal coil centered on the second axis. However, the subcoil SC is formed by a conductor that goes around the second axis. Anything may be used.

  In the antenna according to the present embodiment, eight subcoils SC as described above are provided, but the number of subcoils SC to be provided is not particularly limited.

For the rightmost subcoil SC in the drawing, the magnetic field Hs formed by the current I flowing at a certain instant t is shown. For the other subcoils SC, similarly to the subcoil SC, a magnetic field Hs directed in a direction away from the first axis is formed. Note that the scalar quantity of the magnetic field Hs of any subcoil SC is common.

In the antenna according to the present embodiment, the magnetic field formed by the current I flowing at a certain instant t is formed by combining the magnetic field Hm formed by one main coil MC and the magnetic field Hs formed by eight subcoils SC. A synthesized magnetic field is generated.

In such a composite magnetic field, the magnetic field Hm and the magnetic field Hs cancel each other on the upper surface side of the plane P, and the magnetic field Hm and the magnetic field Hs strengthen each other on the upper surface side of the plane P. Becomes a magnetic field spreading on the lower surface side of the plane P, and is given directivity.

  When such an antenna according to the present invention is applied to the power transmitting antenna 105 and the power receiving antenna 201, the magnetic field leaking from the antenna during power transmission and entering the metal body at the bottom of the vehicle is reduced on the side mounted on the vehicle. Therefore, the bottom of the vehicle is not heated, and in addition, the power transmission efficiency of the system can be improved.

  Next, an example of the winding pattern of the conductor wire 400 when the main coil MC and the subcoil SC defined as described above are formed with the base material 300 will be described with reference to FIG.

  In the present embodiment, after attaching a magnetic core 350 made of a ferromagnetic material such as a ferrite material having a high magnetic permeability and specific resistance to the sub-coil forming projection piece 330, the conductor wire 400 is formed in the pattern shown in FIG. Wind it up. As the conductor wire 400, a stranded wire in which a plurality of conductor wires are assembled is used.

  In FIG. 6, the arrow shown on the conductor wire 400 has shown the order at the time of winding. For example, assuming that the conductor wire 400 starts to be wound from (a) in the drawing, first, the conductor wire 400 is formed on the first surface 301 side of the main coil shaping projection piece 320 from (a) to (b). Lock.

  Subsequently, in the section from (b) to (c), the conductor wire 400 is connected to the second surface of the sub-coil shaping projection piece 330 → the first surface of the sub-coil shaping projection piece 330 → the first of the sub-coil shaping projection piece 330. As in the case of the two surfaces, the coil is wound around the sub-coil forming projection piece 330 over approximately one and a half halves.

  The coil wound as described above in the sub-coil shaping projection piece 330 forms a magnetic field as the sub-coil SC as a whole, and the conductor wire 400 wound on the second surface side of the sub-coil shaping projection piece 330. This also forms a magnetic field as the main coil MC.

  By the winding pattern as described above, winding is sequentially performed in the order of (c) → (d) → (e) →. When all the projecting pieces of the base material 300 are wound in the winding pattern as described above for one circumference around the base material 300, and when returning to (a) again, the projecting pieces extend from the base portion 310. Shift in the direction you want to go and proceed with the winding.

  FIG. 7 shows a case where approximately five turns are wound around the base material 300 as described above. FIG. 7 is a diagram showing an antenna according to an embodiment of the present invention. Note that the number of windings around the substrate 300 is not limited to this.

  The antenna according to the present invention as described above is an antenna having a main coil MC and a plurality of subcoils SC, and corrects the magnetic field generated by the main coil MC with the magnetic fields generated by the plurality of subcoils SC. According to such an antenna according to the present invention, even when the antenna is mounted on the bottom surface of the vehicle, the magnetic field generated by the entire antenna has directivity, so that it leaks from the antenna during power transmission and becomes a metal body at the bottom of the vehicle. The entering magnetic field can be reduced, the vehicle bottom is not heated, and the power transmission efficiency of the system can be improved.

Here, in the antenna according to the present invention, the inductance Lm formed by the contribution of the main coil MC and the inductance Ls formed by all the contributions of the plurality of subcoils SC (eight subcoils SC in the illustrated example). It is preferable to have a relationship of Ls ≦ Lm ≦ 2.5Ls between them.

  This is because when the antenna according to the present invention is mounted on the bottom of a vehicle and the power transmitting antenna 105 and the power receiving antenna 201 are faced to each other in a practical range, an inductance Lm and an inductance Ls that can obtain a power transmission efficiency of a predetermined level or more are obtained. It is a relationship.

  In order to establish the above relationship, as a first method, it is possible to adjust the arrangement of the conductor wire 400 that circulates in the main coil MC. If it demonstrates with the winding pattern shown in FIG. 7, the inductance Lm will be changed by variously adjusting the distance (r in FIG. 7) between the approximate center O of the base material 300 and the conductor wire 400, and the said relationship will be satisfy | filled. Like that.

  Moreover, as a 2nd method, adjusting arrangement | positioning of the conductor wire 400 to circulate which comprises the subcoil SC can be mentioned. More specifically, by adjusting the shape and size of the sub-coil shaping projection piece 330 in various ways, the winding shape of the conductor wire 400 in the sub-coil shaping projection piece 330 is changed, the inductance Ls is changed, and the above relationship is established. Try to meet.

  In addition, as a third method, the relationship can be satisfied by adjusting the number of turns of the main coil MC and the number of turns of the subcoil SC.

  Further, as a fourth method, the relationship can be satisfied by adjusting the number of turns of either the main coil MC or the subcoil SC.

  A method of adjusting the number of turns of the subcoil SC with the winding pattern shown in FIG. 6 will be described. For example, in the winding pattern shown in FIG. 6, in the sections (b) to (c), when the conductor wire 400 is wound around the sub-coil forming projection piece 330, the conductor wire 400 is wound approximately half a turn. However, for example, when the inductance Ls of the subcoil SC is to be increased, the conductor wire 400 wound around the subcoil shaping projection piece 330 is set to approximately two and a half halves so that the inductance Ls of the subcoil SC is obtained. Can be adjusted.

  Further, as a fifth method, the inductance Ls is changed by providing the magnetic core 350 on the inner peripheral side of the conductor constituting the subcoil SC or by omitting it, so that the above relationship is satisfied. Can be mentioned.

  Furthermore, as a sixth method, a magnetic core 350 is provided on the inner peripheral side of the conductor constituting the subcoil SC, and the magnetic permeability of the magnetic core 350 is adjusted, and the size and shape of the magnetic core 350 are adjusted. By changing the inductance Ls, the above relationship can be satisfied.

  Next, the merit of providing the main coil shaping protrusion 320 will be described. FIG. 8 is a diagram for explaining the significance of providing the main coil shaping protrusion 320. FIG. 8A is a view for explaining the winding pattern of the antenna according to the present invention in which the main coil shaping protrusion 320 is provided, and FIG. 8B is the main coil shaping protrusion 320 provided. It is a figure explaining the winding pattern of the antenna which concerns on the comparative example which is not.

  FIG. 8C illustrates the definition of each part in the substrate 300. A perpendicular to a line passing through the approximate center O of the substrate 300 and the intermediate point of the edge 335 of the main coil shaping protrusion 320 (or subcoil shaping protrusion 330) is the main coil shaping protrusion 320 (or subcoil). The length across the shaping protrusion 330) is defined as the “width” of the protrusion.

  Further, a line passing through the approximate center O of the substrate 300 and the intermediate point of the edge 335 of the main coil shaping protrusion 320 (or the sub coil shaping protrusion 330) extends from the end of the base 310 to the edge 335. The distance traveled is defined as the “length” of the protrusion.

  As can be seen from a comparison between FIG. 8A and FIG. 8B, in the antenna according to the present invention in which the main coil shaping protrusion 320 is provided, the conductor wire 400 is substantially at the center of the substrate 300. The shape is closer to a circle centered on O. Thereby, when the main coil shaping protrusion 320 is provided, the inductance Lm generated due to the contribution of the main coil MC can be further increased.

  Further, in the present embodiment, as shown in FIG. 8C, the width of the main coil shaping protrusion 320 and the sub coil shaping protrusion 330 is configured to become wider as the outer peripheral edge of the base material 300 is closer. It is preferable to do. By configuring in this way, it is possible to further reduce the component of the magnetic field radiated in a direction other than the direction perpendicular to the main surface of the substrate 300, and the conductor wire 400 is substantially at the center of the substrate 300. Since a force in the direction of O is generated, the vibration intensity of the antenna can be increased.

  Next, another embodiment of the present invention will be described. FIG. 9 is a diagram showing an antenna according to another embodiment of the present invention.

  So far, in the embodiment described above, the magnetic core 350 is not longer than the length of the sub-coil shaping projection piece 330. However, in this embodiment, the length of the magnetic core 350 is the length of the sub-coil shaping projection piece 330. It is set longer than the length, and is attached to the sub-coil forming projection piece 330 so as to extend toward the base portion 310 side of the base material 300. A portion of the magnetic core 350 extending to the base portion 310 side of the substrate 300 is a portion indicated as P in FIG.

  According to the length and arrangement of the magnetic core 350 as described above, the directivity of the antenna can be further improved by reducing the leakage of the magnetic field in the portion close to the center of the substrate 300.

  FIG. 10 is a diagram showing an antenna according to another embodiment of the present invention. In the embodiment shown in FIG. 10, the length of the magnetic core 350 is set to be longer than the length of the sub-coil shaping projection piece 330 and extends from the edge 335 of the sub-coil shaping projection piece 330. It is characterized by being attached to the projecting piece 330. A portion of the magnetic core 350 extending from the edge portion 335 of the sub-coil shaping projection piece 330 is a portion indicated as Q in FIG.

  According to the length and arrangement of the magnetic core 350 as described above, the directivity of the antenna can be further improved by reducing the leakage of the magnetic field in the portion near the outer peripheral edge of the substrate 300.

  Note that the effect of increasing the directivity of the antenna as described above can be expected even more by the embodiment in which the embodiment shown in FIG. 9 and the embodiment shown in FIG. 10 are combined.

  Further, in the antenna according to the present invention, it is preferable to prepare a plurality of magnetic cores 350 as independent separate bodies, and attach the individual magnetic cores 350 to the respective sub-coil forming protrusions 330. It is not preferable to use an integral-side magnetic core that is connected at the center of the material 300.

Next, another embodiment of the present invention will be described. FIG. 11 is a diagram showing an antenna according to another embodiment of the present invention. FIG. 11 (A) shows a portion constituting the main coil MC of the antenna according to another embodiment, and FIG. 11 (B) shows another antenna. The part which comprises the subcoil SC of the antenna of embodiment is shown, respectively. The antenna according to this embodiment is obtained by superimposing FIGS. 11A and 11B.

  FIG. 12 is a diagram showing an equivalent circuit of an antenna according to another embodiment of the present invention. In FIG. 12, Lm is an inductance formed by the main coil MC, and Ls is an inductance formed by each individual subcoil SC.

In the embodiments described so far, the single substrate 300 is used to form the antenna main coil MC and the subcoil SC simultaneously with the winding pattern shown in FIG.

  In contrast, in the embodiment shown in FIGS. 11 and 12, the two base materials 300 are used, and the main coil MC and the subcoil SC are independently formed on each base material 300.

  In FIG. 11 (A), the conductor wire 400 is spirally wound while being locked to the main coil shaping projection piece 320 and the sub coil shaping projection piece 330, and is exactly shown in the schematic diagram of FIG. The main coil MC is formed.

  On the other hand, only the sub-coil forming projection piece 330 is used to form the sub-coil SC. In this embodiment, as shown in FIG. 11 (B), the conductor coil 400 is wound around the sub-coil shaping projection piece 330 to which the magnetic core 350 is attached, and each sub-coil shaping projection piece 330 has an independent sub-coil SC. Form. These subcoils SC are typically equivalent to those shown in FIG. Further, these subcoils SC are connected in series as shown in FIG.

  Furthermore, as shown in FIG. 12, the series connection of the subcoil SC is also connected in series with the main coil MC. In addition, when connecting each coil as shown in FIG. 12, this is performed so that the magnetic field as demonstrated in FIG.4 and FIG.5 may generate | occur | produce. Furthermore, the antenna according to another embodiment is configured by overlapping the main coil MC of FIG. 11A and the subcoil SC of FIG. Even with the antennas according to the other embodiments as described above, it is possible to receive the same effects as those of the embodiments described so far.

  Next, another embodiment of the present invention will be described. FIG. 13 is a view showing a base material 300 used for modeling an antenna coil according to another embodiment of the present invention. In FIG. 13, the same reference numerals as those in the previous embodiment are the same as those in the previous embodiment, and a description thereof will be omitted.

  The first point that the antenna according to the other embodiment differs from the antenna according to the first embodiment is that, in the antenna according to the first embodiment described above, the main coil shaping protrusion is formed around the base material 300. While the pieces 320 and the sub-coil shaping projection pieces 330 are alternately arranged, in the antenna according to another embodiment, a plurality of continuous main coil shaping projection pieces are provided around the base material 300. 320 and one sub-coil shaping projection piece 330 are alternately arranged.

  In particular, in an antenna according to another embodiment, it is desirable that the number of main coil shaping protrusions 320 continuously arranged around the base material 300 is an odd number. In the embodiment shown in FIG. 13, the number of main coil shaping protrusions 320 that are continuously arranged is three.

  As described above, when the number of main coil shaping protrusions 320 arranged continuously around the base material 300 is an odd number, the conductor wire 400 is wound when the conductor wire 400 is wound as shown in FIG. Since the pattern passed from the first surface 301 to the second surface 302 and from the second surface 302 to the first surface 301 is uniform over the entire circumference of the substrate 300, the antenna 400 is manufactured. Efficiency is improved.

  In addition, the second point that the antenna according to the other embodiment is different from the antenna according to the first embodiment is that the second base material 500 is used. FIG. 14 is a view for explaining attachment of the second base material 500 in an antenna according to another embodiment of the present invention.

  Similar to the base material 300, the second base material 500 is a substrate-like member having a first surface 501 and a second surface 502 in a front-back relationship with the first surface 501 and is a material having a small dielectric loss tangent, such as polycarbonate or polypropylene. It is preferable to configure using

  The second base material 500 includes a base portion 510 that forms a substantially central flat plate portion, and a plurality of sub-coil shaping projection pieces 530 that extend radially from the base portion 510. The sub-coil shaping projection piece 530 of the second base material 500 is used for sandwiching the magnetic core 350 with the sub-coil shaping projection piece 330 of the base material 300 and winding the conductor wire 400.

  As shown in FIG. 14, a magnetic coil 350 made of a ferromagnetic material such as a ferrite material having a high magnetic permeability and specific resistance is attached to the sub-coil forming projection piece 330 of the substrate 300, and then the second coil The base material 500 is attached on the magnetic core 350, and the magnetic core 350 is sandwiched between the sub-coil shaping projection piece 330 of the base material 300 and the sub-coil shaping projection piece 530 of the second base material 500.

  Furthermore, in the antenna according to another embodiment, the conductor wire 400 is wound around the outer periphery of the sub-coil shaping projection piece 330 of the base material 300 and the sub-coil shaping projection piece 530 of the second base material 500, The shape of the subcoil SC is maintained. Thereby, the distance between the conductor wire 400 constituting the sub-coil SC to be shaped and the second axis is increased as compared with the case where only the base material 300 is used, and as a result, the inductance component also increases.

  Next, in an antenna according to another embodiment, refer to FIG. 15 for an example of a winding pattern of the conductor wire 400 when forming the main coil MC and the subcoil SC with the base material 300 and the second base material 500. I will explain.

  In FIG. 15, the arrows shown on the conductor wire 400 indicate the order of winding. For example, assuming that the conductor wire 400 starts to be wound from (a) in the drawing, first, the conductor wire 400 is formed on the first surface 301 side of the main coil shaping projection piece 320 from (a) to (b). Lock.

  Subsequently, in the sections (b) to (c), the conductor wire 400 is connected to the second surface of the sub-coil shaping projection piece 330 of the base material 300 → the first of the sub-coil shaping projection pieces 530 of the second base material 500. Surface → Sub-coil shaping projection piece 330 of the base material 300 and the sub-coil shaping projection piece 530 of the second base material 500, like the second surface of the sub-coil shaping projection piece 330 of the base material 300. Rolled over.

  The coil wound as described above in the sub-coil shaping projection piece 330 forms a magnetic field as the sub-coil SC as a whole, and the conductor wire 400 wound on the second surface side of the sub-coil shaping projection piece 330. This also forms a magnetic field as the main coil MC.

  Subsequently, from (c) to (d), the conductor wire 400 is locked on the first surface 301 side of the main coil shaping projection piece 320.

  Subsequently, from (d) to (e), the conductor wire 400 is locked on the second surface 302 side of the main coil shaping protrusion 320.

  Subsequently, from (e) to (f), the conductor wire 400 is locked on the first surface 301 side of the main coil shaping protrusion 320.

  By the winding pattern as described above, winding is further sequentially performed in the order of (g) → (h) → (i) →. When all the projecting pieces of the base material 300 and the second base material 500 are wound in the winding pattern as described above for one circumference around the base material 300, and when returning to (a) again, the projecting pieces Is shifted in the direction extending from the base 310 and the winding proceeds.

  In the antenna according to another embodiment configured as described above, it is possible to enjoy the same effect as the antenna described so far, and the magnetic core 350 is sandwiched between the two projecting pieces. Manufacturability is good, and it is also possible to increase the inductance component as compared with the case where only the substrate 300 is used.

  As described above, the antenna according to the present invention includes the main coil MC and the plurality of subcoils SC, and corrects the magnetic field generated by the main coil MC with the magnetic field generated by the plurality of subcoils SC. According to such an antenna, even when the antenna is mounted on the bottom surface of the vehicle, the magnetic field generated by the entire antenna has directivity, so that the magnetic field leaking from the antenna during power transmission and entering the metal body at the bottom of the vehicle is reduced. Therefore, the bottom of the vehicle is not heated, and in addition, the power transmission efficiency of the system can be improved.

  Next, another embodiment of the present invention will be described. FIG. 16 is an exploded perspective view of an antenna according to another embodiment of the present invention. The embodiment shown in FIG. 16 is an improvement of the embodiment described with reference to FIGS. 11 and 12.

  In the embodiment described with reference to FIGS. 11 and 12, the base material 300 that constitutes the main coil MC and the base material 300 that constitutes the subcoil SC are formed so as to overlap each other, and the inductance Lm by the main coil MC, All of the inductances Ls due to the SC are connected in series.

  However, in the antenna shown in FIGS. 11 and 12 as described above, the electrical insulation between the base material 300 constituting the main coil MC and the base material 300 constituting the subcoil SC is vulnerable. There is a problem.

  Therefore, in the antenna according to the present embodiment, the base material 300 constituting the main coil MC and the base material constituting the subcoil SC are provided by arranging the third base material 600 which is the third insulating substrate. The electrical insulation with 300 is strengthened. The third base material 600 may be made of a material having a low dielectric loss tangent and high insulation properties such as polycarbonate, polypropylene, polytetrafluoroethylene, and the like. In the present embodiment, the third base material 600 uses the same shape as the base material 300 constituting the main coil MC and the subcoil SC, but is not limited to this, and the main coil MC, Any material can be used as the third base material 600 as long as the insulation between the base materials 300 constituting the subcoil SC can be achieved.

  According to the embodiment as described above, the same effects as those of the embodiments described so far can be enjoyed, and the characteristics of the antenna can be further improved.

DESCRIPTION OF SYMBOLS 100 ... Power transmission system 101 ... AC / DC conversion part 102 ... Voltage adjustment part 103 ... Inverter part 104 ... Matching device 105 ... Power transmission antenna 110 ... Main control part 120- ..Communication unit 201 ... Receiving antenna 202 ... Rectification unit 203 ... Charge control unit 204 ... Battery 210 ... Main control unit 220 ... Communication unit 230 ... Interface unit 300 ... Base material 301 ... first surface 302 ... second surface 310 ... base 320 ... projection piece 322 for main coil shaping ... side portion 325 ... edge 330 ... sub-coil shaping Protruding piece 332... Side portion 335... Edge portion 350... Magnetic core 400... Conductor wire 500. ... Base 530 ... Subcoy Shaped projecting piece 600 ... third base material

Claims (5)

A first substrate;
A second substrate;
A main coil consisting of a conductor wire wound around the first axis and locked to the first base material;
A plurality of subcoils made of a conductor wire wound around a plurality of second axes included in a plane having the first axis as a normal, and being locked to the second base material;
An antenna having a third base material sandwiched between the main coil and the plurality of sub-coils,
The antenna is characterized in that the plurality of subcoils are connected in series, and the main coil is further connected in series to the series connection of the plurality of subcoils. The antenna according to claim 1, wherein a conductor constituting the main coil is spiral in the plane. The antenna according to claim 1 or 2, wherein a magnetic core is disposed on an inner peripheral side of the conductor constituting the sub-coil by turning around. The antenna according to any one of claims 1 to 3, wherein the third base material is made of a material having a small dielectric loss tangent and a high insulating property. The antenna according to any one of claims 1 to 4, wherein any one of polycarbonate, polypropylene, and polytetrafluoroethylene is used as the third base material.

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