Abstract:
In the power supply apparatus ( 100 ), on an upper surface ( 202   a ), which is the surface opposing the power-receiving unit ( 153 ) of a cabinet ( 103   b ), in the portion where a power supply coil ( 103   a ) is projected when the power supply coil ( 103   a ) is projected on the cabinet ( 103   b ) toward the direction of the power-receiving unit ( 153 ), a first inclined part ( 203 ) gradually approaching the power supply coil ( 103   a ) from the top section ( 205 ) toward the inner edge section ( 211 ) of the power supply coil ( 103   a ) is formed in the radial direction of the power supply coil ( 103   a ), and in the portion where the power supply coil ( 103   a ) is projected, a second inclined part ( 204 ) gradually approaching the power supply coil ( 103   a ) from the top section ( 205 ) toward the outer periphery ( 212 ) of the power supply coil ( 103   a ) is formed in the radial direction of the power supply coil ( 103   a ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an electric supply apparatus that contactlessly supplies electric power using electromagnetic induction to an electric reception section provided in a vehicle. 
       BACKGROUND ART 
       [0002]    A typical known contactless electric supply apparatus is one that is placed on a ground surface and supplies electric power to an electric reception section mounted in a vehicle (for example, Patent Literature (hereinafter, abbreviated as PTL) 1). 
         [0003]    In PTL 1, two units, i.e., an electric transmission unit and an electric reception section are provided. The electric transmission unit includes a ring-shaped electric transmission coil and a casing that houses this coil, and is placed on a road surface side position where a vehicle stops, such as a parking space. The electric reception section includes a ring-shaped electric reception coil and a casing that houses this coil, and is placed on the bottom surface of the vehicle at a position that faces the electric transmission unit placed on the ground surface. The surface of the casing that faces the electric reception section of the electric transmission unit (hereinafter referred to as “upper surface”) is formed so as to be in parallel with the radial direction of the electric transmission coil. 
       CITATION LIST 
     Patent Literature 
       [0004]    PTL 1 
         [0005]    Japanese Patent Application Laid-Open No. 2011-10435 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0006]    In the electric supply apparatus according to the related art, however, it is likely that a foreign object is put on the upper surface of the electric transmission unit because the surface of the electric transmission unit is in parallel with the radial direction of the transmission coil. The foreign object on the upper surface involves a problem in that the foreign object is heated to a high temperature by a magnetic flux penetrating the foreign object during electric supply. Moreover, the foreign object heated to a high temperature may cause, for example, a hole at a portion in contact with the foreign object and damage the upper surface. Consequently, the foreign object or the like entering from the damaged portion may affect the electric supply process of the electric transmission coil. 
         [0007]    It is an object of the present invention to provide an electric supply apparatus that can prevent a foreign object from being heated to a high temperature during electric supply. 
       Solution to Problem 
       [0008]    An electric supply apparatus according to an aspect of the present invention is an apparatus that contactlessly supplies electric power using electromagnetic induction to an electric reception section provided in a vehicle, the apparatus including: a ring-shaped electric supply coil that faces the electric reception section and that supplies electric power to the electric reception section; and a casing that houses the electric supply coil, wherein the casing includes a first incline portion, a second incline portion, and a recessed portion on an upper surface of the casing, the upper surface being a surface facing the electric reception section: the first incline portion being formed in a portion of the upper surface where the electric supply coil is projected when the electric supply coil is projected on the casing toward the electric reception section, and gradually approaching the electric supply coil from a top portion on the upper surface toward an inner edge portion of the electric supply coil in a radial direction of the electric supply coil; the second incline portion being formed in the portion of the upper surface where the electric supply coil is projected, and gradually approaching the electric supply coil from the top portion toward an outer circumference of the electric supply coil in the radial direction of the electric supply coil; and a recessed portion being in contact with an end portion of the first incline portion located in a direction different from the top portion. 
       Advantageous Effects of Invention 
       [0009]    According to the present invention, it is possible to prevent a foreign object from being heated to a high temperature during electric supply. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]      FIG. 1  is a block diagram illustrating an example of the configuration of a charging system according to Embodiment 1 of the present invention; 
           [0011]      FIG. 2  is a perspective view of an electric supply section according to Embodiment 1 of the present invention; 
           [0012]      FIG. 3  is a plane view of  FIG. 2 ; 
           [0013]      FIG. 4  is a sectional view taken along line A-A in  FIG. 2 ; 
           [0014]      FIG. 5  is a sectional view taken along line B-B in  FIG. 2 ; and 
           [0015]      FIG. 6  is a sectional view taken along line C-C in  FIG. 2 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0016]    Hereafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
       Embodiment 1 
       [0017]    &lt;Configuration of Charging System&gt; 
         [0018]      FIG. 1  is a block diagram illustrating an example of the configuration of charging system  10  in Embodiment 1 of the present invention. 
         [0019]    Charging system  10  includes electric supply apparatus  100 , vehicle  150 , storage battery  154 , and charging apparatus  170 . 
         [0020]    Electric supply apparatus  100  is placed on a ground surface or buried so that electric supply section  103  is exposed from land surface g. Electric supply apparatus  100  is provided, for example, in a parking space and supplies electric power to charging apparatus  170  while facing electric reception section  153 , during parking of vehicle  150 . The configuration of electric supply apparatus  100  will be described below. 
         [0021]    Vehicle  150  includes storage battery  154  and charging apparatus  170 , and runs with storage battery  154  as a power source. Vehicle  150  is, for example, an automobile that can run with the electric power of storage battery  154  such as an HEV (Hybrid Electric Vehicle), a PHEV (Plug-in Hybrid Electric Vehicle), or an EV (Electric Vehicle). 
         [0022]    Storage battery  154  stores the electric power supplied from charging apparatus  170 . 
         [0023]    Charging apparatus  170  includes vehicle side control section  151  and electric reception apparatus  160 , and supplies the electric power supplied from electric supply apparatus  100 , to storage battery  154 . The configuration of charging apparatus  170  will be described below in detail. 
         [0024]    Vehicle side control section  151  controls electric reception apparatus  160  to perform various processes associated with charging or various processes associated with the stop of charging. 
         [0025]    Electric reception apparatus  160  supplies the electric power supplied from electric supply apparatus  100 , to storage battery  154  according to the control of vehicle side control section  151 . The configuration of electric reception apparatus  160  will be described below. 
         [0026]    &lt;Configuration of Electric Supply Apparatus&gt; 
         [0027]    Electric supply apparatus  100  includes electric supply side communication section  101 , electric supply side control section  102 , and electric supply section  103 . 
         [0028]    Electric supply side communication section  101  receives an electric supply start signal or an electric supply stop signal from vehicle side communication section  152 . Electric supply side communication section  101  outputs the received electric supply start signal or electric supply stop signal to electric supply side control section  102 . 
         [0029]    Electric supply side control section  102  controls electric supply section  103  to start electric supply according to the electric supply start signal inputted from electric supply side communication section  101 . Electric supply side control section  102  controls electric supply section  103  to stop electric supply according to the electric supply stop signal inputted from electric supply side communication section  101 . 
         [0030]    Electric supply section  103  includes electric supply coil  103   a.  Electric supply section  103  supplies the current having a predetermined frequency to electric supply coil  103   a  according to the control of electric supply side control section  102  to thereby supply electric power using electromagnetic induction to electric reception section  153 . This electric supply is performed in an electromagnetic induction system or a magnetic resonance system, for example. The configuration of electric supply section  103  will be described below in detail. 
         [0031]    &lt;Configuration of Electric Reception Apparatus&gt; 
         [0032]    Electric reception apparatus  160  includes vehicle side communication section  152  and electric reception section  153 . 
         [0033]    Vehicle side communication section  152  generates a charging start signal or a charging stop signal according to control of vehicle side control section  151 , and transmits the generated charging start signal or charging stop signal to electric supply side communication section  101 . 
         [0034]    Electric reception section  153  is provided at the bottom portion of vehicle  150 . Electric reception section  153  includes electric reception coil  153   a  and contactlessly faces electric supply section  103  when storage battery  154  is charged. Electric reception section  153  supplies the electric power, which is supplied from electric supply section  103  to electric reception coil  153   a,  to storage battery  154  according to the control of vehicle side control section  151 . 
         [0035]    &lt;Configuration of Electric Supply Section&gt; 
         [0036]      FIG. 2  is a perspective view of electric supply section  103 , and  FIG. 3  is a plane view of electric supply section  103  viewed from the direction of electric reception section  153 .  FIG. 4  is a sectional view taken along line A-A in  FIG. 2 ,  FIG. 5  is a sectional view taken along line B-B in  FIG. 2 , and  FIG. 6  is a sectional view taken along line C-C in  FIG. 2 . Hereinafter, the configuration of electric supply section  103  will be described mainly with reference to  FIG. 2  and  FIG. 4 . 
         [0037]    Electric supply section  103  includes electric supply coil  103   a  and casing  103   b.    
         [0038]    Electric supply coil  103   a  is of a hollow ring shape and placed on inner bottom surface (base)  201  of casing  103   b.  Electric supply coil  103   a  is connected, for example, to a commercial power source and supplies electric power to electric reception section  153  by supplying a current from this power source. Electric supply coil  103   a  is formed, for example, by winding a metallic thin wire. 
         [0039]    Casing  103   b  includes base  201  and cover  202 . Base  201  is formed, for example, in a square flat plate shape (for example, see  FIG. 3 ). Base  201  is formed of a material, such as aluminum. Electric supply coil  103   a  is placed on base  201 , and cover  202  is attached to base  201 . 
         [0040]    Cover  202  is formed of, for example, a nonmetallic material, such as a reinforced plastic. Cover  202  includes upper surface  202   a  that is a surface facing electric reception section  153  in casing  103   b,  flat portion  202   b  that is a portion other than upper surface  202   a  in the surface facing electric reception section  153  in casing  103   b,  and outer wall portion  202   c  that is the side portion of cover  202 . When cover  202  is attached to base  201 , casing  103   b  has first incline portion  203 , second incline portion  204 , and recessed portion  206  on upper surface  202   a.  More specifically, casing  103   b  has first incline portion  203  and second incline portion  204  in a portion on which electric supply coil  103   a  is projected when electric supply coil  103   a  is projected on casing  103   b  toward electric reception section  153  on upper surface  202   a.    
         [0041]    First incline portion  203  is formed so as to incline downward from circular top portion  205  toward inner edge portion  211  of electric supply coil  103   a  in the radial direction of electric supply coil  103   a,  i.e., so as to incline while gradually approaching electric supply coil  103   a.  Herein, the radial direction of electric supply coil  103   a  is a direction orthogonal to central axis P 1  of electric supply coil  103   a.  First incline portion  203  is formed so as to have one end connected to top portion  205  and the other end connected to recessed portion  206  (side portion  206   a ). 
         [0042]    Second incline portion  204  is formed so as to incline downward from circular top portion  205  toward outer circumference  212  of electric supply coil  103   a  in the radial direction of electric supply coil  103   a,  i.e., so as to incline while gradually approaching electric supply coil  103   a.  Second incline portion  204  is formed so as to have one end connected to top portion  205  and the other end connected to flat portion  202   b.    
         [0043]    Recessed portion  206  is placed at a position corresponding to the hollow portion of electric supply coil  103   a.  Recessed portion  206  is formed so as to have side portion  206   a  connected to first incline portion  203  and bottom portion  206   b  that faces and is connected to base  201 . 
         [0044]    Trench  207  is formed at bottom portion  206   b  of recessed portion  206 . Trench  207  is provided for housing a foreign object sliding down from first incline portion  203 . Trench  207  may have a shape capable of housing a foreign object and preventing a human finger or the like from touching the housed foreign object. 
         [0045]    Reinforcement member  208  supports first incline portion  203 . Reinforcement member  208  is formed, for example, of an insulator. This can secure the withstand load when the tires of vehicle  150  pass on casing  103   b.    
       ADVANTAGEOUS EFFECT OF PRESENT EMBODIMENT 
       [0046]    In the present embodiment, two incline portions formed on upper surface  202   a  of casing  103   b,  i.e., first incline portion  203  that gradually approaches electric supply coil  103   a  toward the center of electric supply coil  103   a  and second incline portion  204  that gradually approaches electric supply coil  103   a  toward outer circumference  212  of electric supply coil  103   a  in the radial direction of electric supply coil  103   a.  Thereby, a foreign object on first incline portion  203  slides down to recessed portion  206  provided in the center portion of electric supply section  103 . In this configuration, recessed portion  206  corresponds to the hollow portion of electric supply coil  103   a,  as described above. Meanwhile, heat generation of a foreign object in recessed portion  206  is small in comparison with that in the vicinity of electric supply coil  103   a.  As a result, a foreign object on first incline portion  203  slides down to recessed portion  206  and can therefore be prevented from being heated to a high temperature. A foreign object on second incline portion  204  also slides down to the exterior of electric supply section  103  and can therefore be prevented from being heated to a high temperature. 
         [0047]    Moreover, in the present embodiment, the two incline portions, i.e., first incline portion  203  and second incline portion  204  are formed in a portion of casing  103   b  of electric supply section  103 , the portion facing electric reception section  153 . Generally, in the present embodiment, large electric power is supplied to electric reception section  153  at the bottom portion of vehicle  150 , so that the shape of electric supply coil  103   a  becomes large, and casing  103   b  of electric supply section  103  cannot be provided with a sufficient curved surface due to the relation with the clearance between electric supply section  103  and the bottom portion of vehicle  150 . With regard to this problem, according to the present embodiment, forming the two incline portions in a portion of casing  103   b,  which faces electric reception section  153 , allows for a reduction in the thicknesses of the incline portions (first incline portion  203  and second incline portion  204 ) in comparison with the case of forming one incline portion in a portion of casing  103   b,  which faces electric reception section  153 . Therefore, the height of electric supply section  103  toward the bottom surface of vehicle  150  can be reduced to thereby maintain the clearance between electric supply section  103  and the bottom portion of vehicle  150 . 
         [0048]    In the present embodiment, as illustrated in  FIG. 4 , it is preferable that top portion  205  on casing  103   b  be located at intermediate position  213  between inner edge portion  211  and outer circumference  212  of electric supply coil  103   a  in the direction of central axis P 1  of electric supply coil  103   a.  This is because a foreign object at a position corresponding to intermediate position  213  in the radial direction of electric supply coil  103   a  is heated most readily. Locating top portion  205  that is most distant from electric supply coil  103   a  in the direction of central axis P 1  on casing  103   b  at a position corresponding to the intermediate position  213  where a foreign object is heated most readily allows for minimizing heat generation of the foreign object even when the foreign object remains without sliding down. 
         [0049]    Moreover, in the present embodiment, first incline portion  203  and second incline portion  204  may be covered with a protective cover coated with a material having a frictional coefficient less than a predetermined value. For example, the predetermined value may be set to approximately a value that makes a foreign object on each incline portion slidable. This enables a foreign object to readily slide on first incline portion  203  and second incline portion  204  and to surely slide down to recessed portion  206  or to the exterior of electric supply section  103 . 
         [0050]    In the above-described embodiment, a through-hole may be provided at bottom portion  206   b  of recessed portion  206  instead of trench  207 . The through-hole is provided for ejecting a foreign object sliding down from first incline portion  203  to the exterior. 
         [0051]    Moreover, in electric supply section  103  according to the above-described embodiment, recessed portion  206  may be provided with a distributing water pipe for discharging water. This can prevent water from accumulating in recessed portion  206 . 
         [0052]    The disclosure of the specification, drawings, and abstract in Japanese Patent Application No. 2012-073709 filed on Mar. 28, 2012, is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0053]    An electric supply apparatus according to the present invention is suitable for contactlessly supplying electric power to an electric reception section provided in a vehicle. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           103  Electric supply section 
           103   a  Electric supply coil 
           103   b  Casing 
           153  Electric reception section 
           201  Base 
           202  Cover 
           202   a  upper surface 
           202   b  Flat portion 
           202   c  Outer wall portion 
           203  First incline portion 
           204  Second incline portion 
           205  Top portion 
           206  Recessed portion 
           207  Trench 
           208  Reinforcement member 
           211  Inner edge portion 
           212  Outer circumference 
           213  Intermediate position