Patent Document

TECHNICAL FIELD 
       [0001]    The present invention relates to an electric charger (battery charger) and a mounting structure for an electric charger (battery charger attaching structure), and more particularly to an electric charger mounting structure for maintaining the durability, performance, etc. of an electric charger that is separate from a vehicle which incorporates the electric charger therein. 
       BACKGROUND ART 
       [0002]    There has heretofore been available a technology wherein an electric charger for charging the battery of a two-wheeled electric vehicle is disposed below the rider&#39;s seat of the vehicle (Japanese Patent No. 3055706). 
         [0003]    According to another available technology, an electric charger has an appearance jointly provided by a storage unit and a cover, and an AC cord and a DC cord are wound in a recess that is defined by the storage unit and the cover (Japanese Laid-Open Patent Publication No. 2004-079320). 
       SUMMARY OF INVENTION 
       [0004]    According to the technology disclosed in Japanese Patent No. 3055706, the vehicle has a large weight and a low mileage because it moves while carrying the electric charger. Therefore, the electric charger should preferably be separate from the vehicle. When the battery on the vehicle is to be charged by the separate electric charger, the user often places the electric charger on the road. If the road is wet, for example, durability and performance of the electric charger tends to be lowered. If the vehicle is a scooter-type two-wheeled electric vehicle, then the electric charger may be placed on the step floor thereof when it charges the battery on the two-wheeled electric vehicle. If at this time the two-wheeled electric vehicle is supported on its side stand, then the two-wheeled electric vehicle is inclined to the vertical. Accordingly, it is desirable for the two-wheeled electric vehicle to have a structure by which the electric charger can be firmly secured to the step floor. 
         [0005]    If the electric charger that is separate from the vehicle is used, it is necessary to store the electric cord of the electric charger in order to prevent the electric cord from being deteriorated in quality. Though the technology disclosed in Japanese Laid-Open Patent Publication No. 2004-079320 allows the electric cord to be stored, it discloses nothing about the storage of a plug or the like that is connected to an end of the electric cord. When the electric charger is placed in a storage box and carried around, the plug may possibly interfere with other objects stored in the storage box. 
         [0006]    It is an object of the present invention to provide an electric charger which is separate from a vehicle and a mounting structure for such an electric charger, which make it possible to keep the durability and performance of the electric charger. 
         [0007]    To achieve the above object, there is provided, in accordance with claim  1  of the present invention, a mounting structure for installing an electric charger on a vehicle ( 10 ) including a battery ( 18 ), an electric motor ( 16 ) for generating propulsive force to move the vehicle ( 10 ) based on electric power supplied from the battery ( 18 ), and a vehicle frame cover ( 12 ,  54 ,  55 ,  62 ) which covers the vehicle ( 10 ), wherein the electric charger ( 200 ) charges the battery ( 18 ) and is separate from the vehicle ( 10 ), the mounting structure comprising a mount ( 96 ) disposed on the vehicle frame cover, for installing the electric charger ( 200 ) on the vehicle ( 10 ). 
         [0008]    According to claim  2  of the present invention, in the mounting structure for installing an electric charger according to claim  1 , the mount ( 96 ) is disposed on an upper portion of a leg shield ( 55 ). 
         [0009]    According to claim  3  of the present invention, in the mounting structure for installing an electric charger according to claim  1 , the mount ( 96 ) is disposed on a step floor ( 12 ). 
         [0010]    According to claim  4  of the present invention, in the mounting structure for installing an electric charger according to claim  1 , the mount ( 96 ) is disposed on a lower portion of a seat cover ( 62 ). 
         [0011]    According to claim  5  of the present invention, in the mounting structure for installing an electric charger according to any one of claims  1  through  4 , the vehicle ( 10 ) includes a charging connector ( 20 ) for charging the battery ( 18 ), an electric charger ( 200 ) having an electric charging cord ( 203 ) to be connected to the charging connector ( 20 ). 
         [0012]    According to claim  6  of the present invention, in the mounting structure for installing an electric charger according to claim  5 , the electric charging cord ( 203 ) is of such a length that the electric charging cord ( 203 ) is kept out of contact with the ground, when the electric charger ( 200 ) is installed on the mount ( 96 ). 
         [0013]    According to claim  7  of the present invention, in the mounting structure for installing an electric charger according to claim  5  or  6 , the charging connector ( 20 ) is oriented obliquely forwardly and outwardly as viewed from a front end of a vehicle ( 10 ). 
         [0014]    According to claim  8  of the present invention, in the mounting structure for installing an electric charger according to any one of claims  5  through  7 , the vehicle ( 10 ) includes a side stand ( 72 ), and the charging connector ( 20 ) is disposed on the same side of the vehicle ( 10 ) as the side stand ( 72 ). 
         [0015]    According to claim  9  of the present invention, in the mounting structure for installing an electric charger according to any one of claims  5  through  8 , the vehicle ( 10 ) includes a seat cover ( 62 ) having a charging lid ( 74 ) on a side surface of a vehicle, and the charging connector ( 20 ) is disposed behind the charging lid ( 74 ). 
         [0016]    To achieve the above object, there is provided, in accordance with claim  10  of the present invention, an electric charger ( 400 ) comprising a storage case ( 402 ) housing a charger unit ( 434 ) therein, a take-up recess ( 406 ) defined in an outer circumferential surface of the storage case ( 402 ), a first charging electric cord ( 408 ) connected to the charger unit ( 434 ) being wound around the take-up recess ( 406 ), and a plug cavity ( 416 ) defined in the storage case ( 402 ) for receiving therein a plug ( 412 ) connected to a distal end of the first charging electric cord ( 408 ). 
         [0017]    According to claim  11  of the present invention, in the electric charger ( 400 ) according to claim  10 , the plug cavity ( 416 ) is disposed at a position corresponding to a position of the plug ( 412 ) at a time when winding of the first charging electric cord ( 408 ) around the storage case ( 402 ) is finished. 
         [0018]    According to claim  12  of the present invention, the electric charger ( 400 ) according to claim  10  or  11  further comprises a magnet ( 418 ,  420 ) disposed in at least one of the plug ( 412 ) and the plug cavity ( 416 ). 
         [0019]    According to claim  13  of the present invention, in the electric charger ( 400 ) according to any one of claims  10  through  12 , the plug ( 412 ) is angularly movable with respect to the first charging electric cord ( 408 ). 
         [0020]    According to claim  14  of the present invention, the electric charger ( 400 ) according to any one of claims  10  through  13  further comprises a cooling fan ( 428 ) for cooling the charger unit ( 434 ), the cooling fan ( 428 ) being disposed in the storage case ( 402 ) above the take-up recess ( 406 ). 
         [0021]    According to claim  15  of the present invention, the electric charger ( 400 ) according to any one of claims  10  through  14 , further comprises a spool ( 432 ) disposed in the storage case ( 402 ), and a second charging electric cord ( 430 ) which is wound around the spool ( 432 ), wherein the spool ( 432 ) is disposed below the take-up recess ( 406 ). 
         [0022]    According to claims  1  and  3  described above, since the electric charger is kept out of contact with the road while it is charging the battery, the durability and performance of the electric charger are maintained. The electric charger is firmly secured to the vehicle. 
         [0023]    According to claim  2  described above, the user of the electric charger is not required to bend over and hence does not have to change its posture when installing the electric charger on the vehicle. 
         [0024]    According to claim  4  described above, the electric charger is prevented from being wetted by rainwater. 
         [0025]    According to claims  5  and  6  described above, the electric charger and the electric charging cord are prevented from contacting the road. 
         [0026]    According to claim  7  described above, the electric charging cord can easily be connected to the charging connector. 
         [0027]    According to claim  8  described above, the electric charger can prevent blockage of the traffic on the road while charging the battery. 
         [0028]    According to claim  9  described above, the electric charging cord is prevented from being wetted by rainwater. 
         [0029]    According to claim  10  described above, the electric charger with the first charging electric cord wound in the take-up recess has a neat and smart appearance and makes itself compact. As the plug is housed in the plug cavity, the plug does not interfere with other objects stored in a storage box in which the electric charger is placed when the user carries the storage box. 
         [0030]    According to claim  11  described above, the electric charger with the first charging electric cord being wound up is rendered more compact. 
         [0031]    According to claim  12  described above, the plug is easily secured in place. 
         [0032]    According to claim  13  described above, the plug can be conveniently placed in the plug cavity when the first charging electric cord is placed in the take-up recess, and the electric charger with the first charging electric cord wound in the take-up recess has a neater and smarter appearance. 
         [0033]    According to claim  14  described above, the cooling fan can easily be positioned when it is to be installed. 
         [0034]    According to claim  15  described above, the space available in the storage case is efficiently utilized. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0035]      FIG. 1  is a side elevational view showing major structural details of a two-wheeled electric vehicle  10  according to a first embodiment of the present invention; 
           [0036]      FIG. 2  is a perspective view of the two-wheeled electric vehicle  10  shown in  FIG. 1  with a vehicle frame cover being removed; 
           [0037]      FIG. 3  is an enlarged fragmentary perspective view showing a charging connector  20  which is seen when a charging lid  74  is opened, on the two-wheeled electric vehicle  10  shown in  FIG. 1 ; 
           [0038]      FIG. 4  is a view of an electric charger  200  according to the first embodiment of the present invention; 
           [0039]      FIG. 5  is a side elevational view showing the electric charger  200  which is mounted on the two-wheeled electric vehicle  10  and has a connector  203   a  connected to the charging connector  20 ; 
           [0040]      FIG. 6  is a view showing another structure of the charger mount  96 ; 
           [0041]      FIG. 7  is a transverse cross-sectional view of the two-wheeled electric vehicle  10  with the electric charger  200  installed on the charger mount  96 ; 
           [0042]      FIG. 8  is a block diagram of an electric system of the two-wheeled electric vehicle  10 ; 
           [0043]      FIG. 9  is a perspective view of an electric charger  400  according to a second embodiment of the present invention; 
           [0044]      FIG. 10  is a perspective view of the electric charger  400  according to the second embodiment of the present invention; 
           [0045]      FIG. 11  is a fragmentary cross-sectional view taken along line XI-XI of  FIG. 9 ; 
           [0046]      FIG. 12  is a rear elevational view of the electric charger  400  according to the second embodiment of the present invention; 
           [0047]      FIG. 13  is a side elevational view of the electric charger  400  according to the second embodiment of the present invention; and 
           [0048]      FIG. 14  is a cross-sectional view taken along line XIV-XIV of  FIG. 9 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0049]    Electric chargers and mounting structures therefor according to preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. 
       1st Embodiment 
       [0050]      FIG. 1  is a side elevational view showing major structural details of a two-wheeled electric vehicle  10  according to a first embodiment of the present invention, and  FIG. 2  is a perspective view of the two-wheeled electric vehicle  10  shown in  FIG. 1  with a vehicle frame cover being removed. As shown in  FIGS. 1 and 2 , the two-wheeled electric vehicle  10  has a step floor  12  as part of the vehicle frame cover and a swing arm  14  housing therein an electric motor  16  for generating rotational drive power to drive a rear wheel WR. The electric motor  16  is supplied with electric power from a main battery  18  disposed beneath the step floor  12 . The main battery  18  is charged by an electric charger that is connected to a charging connector  20  which is disposed in a vehicle frame assembly of the two-wheeled electric vehicle  10 . The vehicle frame assembly is covered with the vehicle frame cover. 
         [0051]    The vehicle frame assembly includes a main frame  22  supporting, on its upper end, a head pipe  26  by which a steering system  24   a  is rotatably supported. A pair of left and right front forks  28  is connected to the lower end of the steering system  24   a , and by the pair of left and right front forks  28 , a front wheel WF is rotatably supported. The front wheel WF can be steered by a pair of left and right handles  24  mounted on the upper end of the steering system  24   a.    
         [0052]    The vehicle frame assembly also includes a pair of left and right side frames  30  having respective upper ends joined to a substantially vertically central portion of the main frame  22 . The left and right side frames  30  include respective oblique portions extending obliquely downwardly from the upper ends thereof and respective horizontal portions bent at the lower ends of the oblique portions and extending horizontally. The main battery  18 , which has a voltage of 72 V, for example, for supplying electric power to the electric motor  16  is disposed between the horizontal portions of the left and right side frames  30 . The left and right side frames  30  include respective rear oblique portions bent obliquely upwardly at an end of the horizontal portions thereof and joined to respective rear frames  32  extending obliquely upwardly and rearwardly. 
         [0053]    A lower cross front frame  34  extends between and is fixed to the front ends of the horizontal portions of the left and right side frames  30 , and a lower cross rear frame  36  extends between and is fixed to the rear ends of the horizontal portions of the left and right side frames  30 . The main frame  22  has a lower end joined to a horizontally central portion of the lower cross front frame  34 . The main battery  18  is interposed between the lower cross front frame  34  and the lower cross rear frame  36  in a front-back direction. The main battery  18  is thus surrounded by the left and right side frames  30 , the lower cross front frame  34 , and the lower cross rear frame  36  and is firmly mounted on the vehicle frame assembly. 
         [0054]    Side brackets  38 , each channel-shaped, are mounted respectively on the side frames  30  and on respective sides of the main battery  18 . A strap plate  40  is attached at its ends to the side brackets  38  transversely across the main battery  18  and fastens the main battery  18  with respect to the side frames  30 . 
         [0055]    Pivot plates  44  with respective swing arm pivots  42  formed therein are attached to the rear sides of the rear oblique portions of the left and right side frames  30 . The swing arm  14  is swingably supported at its front end by the swing arm pivots  42 . The swing arm  14  is of a cantilevered structure, in which only an arm on the left side in the transverse direction of the vehicle supports the rear wheel WR. The rear wheel WR is rotatably supported on a rear end portion of the swing arm  14  by an axle  46 . The rear end of the swing arm  14  is suspended from the left one of the rear frames  32  by a rear shock unit  48 . 
         [0056]    A power drive unit  50  which is housed in a cover member  52  is supported on a lower portion of the swing arm  14 . The power drive unit  50  converts a direct current supplied from the main battery  18  into an alternating current and supplies the alternating current to the electric motor  16  via a wire harness L. The electric motor  16  transmits its power to the axle  46  and then the rear wheel WR successively through a first speed reduction gear G 1  and a second speed reduction gear G 2 . The power drive unit  50  includes a smoothing capacitor H. 
         [0057]    The vehicle frame cover includes a front cover  54  disposed in front of the handles  24  and which serves as part of the vehicle frame cover for covering the two-wheeled electric vehicle  10 . A meter unit  56  including a speedometer, etc. is mounted on an upper portion of the front cover  54 . A front headlight  58  and a front luggage carrier  60  are mounted on a front side of the front cover  54 . The vehicle frame cover also includes a leg shield  55  disposed behind the head pipe  26  and contiguous to the front cover  54  and which serves as part of the vehicle frame cover for covering the two-wheeled electric vehicle  1 . The leg shield  55  serves to protect the front portions of the legs of a rider who is seated on a rider&#39;s seat  94 . 
         [0058]    A front fender  98 , which serves as part of the vehicle frame cover, is disposed above the front wheel WF. The step floor  12  for the rider to place its feet thereon is disposed above the main battery  18 . The vehicle frame cover also includes a seat cover  62  disposed around the rear frames  32  and which serves as part of the vehicle frame cover for covering the two-wheeled electric vehicle  10 . The rider&#39;s seat  94  is mounted on the seat cover  62 . A tail lamp  64 , a rear fender  66 , and a rear luggage carrier  68  are attached to a rear end portion of the seat cover  62 . The seat cover  62  has a front lower portion and a front upper portion which slightly projects upwardly in comparison to the front lower portion. 
         [0059]    A central stand  70  having two legs that are spaced from each other in the transverse directions of the vehicle is mounted on the pivot plates  44 . A side stand  72  is mounted on one of the pivot plates  44  provided at left and right sides of the two-wheeled electric vehicle  1 . If the two-wheeled electric vehicle  10  is designed for use in Japan, then the side stand  72  is positioned on the left side of the vehicle frame assembly. 
         [0060]    A charging lid  74  is openably and closably attached to the same side of the seat cover  62  as the side stand  72 . The charging lid  74  can be opened and closed about a hinge  76 . When the charging lid  74  is opened, the charging connector  20  is exposed. The charging connector  20  is disposed on the same side of the vehicle frame assembly as the side stand  72 . 
         [0061]    The electric charger is installed on a mount  96  which is disposed on an upper portion of the leg shield  55 . Since the mount  96  is disposed on the upper portion of the leg shield  55 , the user does not have to bend over and hence does not have to change its posture when installing the electric charger on the mount  96 . The mount  96  may be positioned at such a height that the electric charger will not be held in contact with the step floor  12  when the electric charger is installed on the mount  96 . The mount  96  is in the shape of a hook having a tip end curved and extending upwardly. The mount  96  is located in such a position that the electric charger will not be brought into contact with the road when the electric charger is installed on the mount  96 . 
         [0062]    The mount  96  may be disposed on the seat cover  62 , e.g., a front side of the seat cover  62 , as indicated by the two-dot-and-dash lines in  FIG. 1 . If the mount  96  is disposed on the front side of the seat cover  62 , then since the front upper portion of the seat cover  62  hangs over the electric charger mounted on the mount  96 , and thus the electric charger is not wetted while charging the main battery  18  when it is raining. The mount  96  may be disposed on the same side of the seat cover  62  as the side stand  72 . In this case, since the two-wheeled electric vehicle  10  is inclined to the vertical when it is supported on the side stand  72 , the two-wheeled electric vehicle  10  itself hangs over the electric charger mounted on the mount  96 , thereby preventing the electric charger from being wetted while charging the main battery  18  when it is raining. The electric charger is prevented more effectively from being wetted if the mount  96  is disposed on a lower portion of the seat cover  62 . 
         [0063]    An auxiliary battery  80  having a voltage of 12 V for supplying electric power to accessories including the front headlight  58  and an ECU (Engine Control Unit)  86  is disposed on a right side of the head pipe  26  in the transverse directions of the vehicle. The auxiliary battery  80  is charged with electric power from the main battery  18 . Inside the seat cover  62  and behind the main battery  18 , there are disposed a DC-to-DC converter  82  for converting the voltage of 72 V from the main battery  18  into a voltage of 14.5 V and a contactor box  84  housing therein fuses, relays, etc. The ECU  86  which controls the electric motor  16  via the power drive unit  50 , etc. is disposed on an outer side of the left rear frame  32  in the transverse directions of the vehicle. The auxiliary battery  80  may be dispensed with. 
         [0064]    The main battery  18  has an opening defined in a rear portion thereof and associated with a sirocco fan  88 . The main battery  18  also has an opening defined in a front portion thereof and connected to the lower end of an air intake pipe  90  which extends upwardly along the main frame  22 . The air intake pipe  90  has an upper end connected to an air cleaner  92  which is disposed above the step floor  12 . The air intake pipe  90  and the air cleaner  92  are housed in the front cover  54 . The sirocco fan  88  is housed in the seat cover  62 . The air cleaner  92  has an air inlet port defined in the leg shield  55 . The air cleaner  92  introduces ambient air through the air intake pipe  90  into the main battery  18 . The sirocco fan  88  discharges air out of the main battery  18  to the outside. Thus, the heat generated by the main battery  18  can be released so as to cool the main battery  18 . 
         [0065]      FIG. 3  is an enlarged fragmentary perspective view showing the charging connector  20  which is seen when the charging lid  74  is opened, on the two-wheeled electric vehicle  10  shown in  FIG. 1 . The charging lid  74  is omitted from illustration in  FIG. 3  in order to show the charging connector  20  clearly. The charging connector  20  is oriented obliquely forwardly as viewed from the front end of the two-wheeled electric vehicle  10 , and is oriented outwardly of the two-wheeled electric vehicle  10 . That is, the outlet of the charging connector  20  is open obliquely forwardly as viewed from the front end of the vehicle  10 , and is open outwardly of the two-wheeled electric vehicle  10 . The charging connector  20  is oriented outwardly of the side of the two-wheeled electric vehicle  10  where the charging lid  74  is positioned. Therefore, it is easy for the user to insert the electric charging cord of the electric charger into the charging connector  20 . 
         [0066]    As the charging lid  74  and the charging connector  20  are disposed on the same side of the two-wheeled electric vehicle  10  as the side stand  72 , the main battery  18  can be charged through the charging connector  20  without blocking traffic on the road where the two-wheeled electric vehicle  10  is parked, and the user of the two-wheeled electric vehicle  10  can charge the main battery  18  safely without need to worry about any traffic accident. Furthermore, since the charging lid  74  and the charging connector  20  are disposed above the step floor  12  and below the rider&#39;s seat  94 , the user can easily open and close the charging lid  74  and connect the electric charger to the charging connector  20  without bending over. The charging lid  74  and the charging connector  20  may alternatively be disposed directly below the rider&#39;s seat  94 . 
         [0067]      FIG. 4  is a view of an electric charger  200  according to the first embodiment of the present invention. As shown in  FIG. 4 , the electric charger  200  comprises a storage case  201  housing a charger unit therein, an electric charging cord  203 , and an electric charging cord  204 . The storage case  201  has an opening  202  defined in a wall thereof. When the mount  96  engages in the opening  202 , the electric charger  200  is installed on the two-wheeled electric vehicle  10 . The electric charging cord  203  has a connector  203   a  connected to its distal end and has an opposite end electrically connected to the charger unit. The electric charging cord  204  has a plug  204   a  connected to its distal end for connection to a commercial power supply outlet and has an opposite end electrically connected to the charger unit. The electric charger  200  also includes an AC-to-DC converter, not shown, for converting an AC voltage supplied from the commercial power supply outlet into a DC voltage required to charge the main battery  18 . 
         [0068]      FIG. 5  is a side elevational view showing the electric charger  200  which is mounted on the two-wheeled electric vehicle  10  and has the connector  203   a  connected to the charging connector  20 . When the plug  204   a  is inserted into the commercial power supply outlet, the electric power from the commercial power supply outlet is supplied through the electric charging cord  204  to the electric charger  200 , which charges the main battery  18 . The electric charging cord  203  is of such a length that it does not touch the road when the electric charger  200  is installed on the mount  96  and the connector  203   a  is connected to the charging connector  20 . The storage case  201  stores therein the electric charging cord  204  in a take-up manner. The storage case  201  may also store therein the electric charging cord  203  in a take-up manner. Though the mount  96  is in the shape of a hook in the illustrated embodiment, it may be any of various other shapes insofar as the electric charger  200  can be installed thereon. 
         [0069]      FIG. 6  is a view showing another structure of the mount  96 . In  FIG. 6 , the mount  96  comprises a plurality of recesses  96   a  defined in the step floor  12 . The electric charger  200  has a plurality of teeth  205  on its bottom. When the teeth  205  are fitted respectively in the recesses  96   a , the electric charger  200  is installed on the two-wheeled electric vehicle  10 . 
         [0070]    Since the mount  96  is disposed on the vehicle frame cover of the two-wheeled electric vehicle  10 , the electric charger  200  is held out of contact with the road while the main battery  18  is being charged by the electric charger  200 . Therefore, durability and performance of the electric charger  200  can be maintained. As the electric charger  200  is securely installed on the mount  96 , the electric charger  200  does not fall off during its usage and is prevented from being broken or damaged. The electric charger  200  shown in  FIG. 6  may be free of the opening  202 . 
         [0071]      FIG. 7  is a transverse cross-sectional view of the two-wheeled electric vehicle  10  with the electric charger  200  installed on the mount  96 , the view being taken along a line extending across the step floor  12 . The mount  96  has a plurality of recesses  96   a  defined in the step floor  12  which are spaced from each other in the transverse directions of the vehicle. The electric charger  200  has a plurality of teeth  205  on its lower surface which is of the largest surface area thereof. In other words, the teeth  205  are disposed on the surface of the electric charger  200  which is held in contact with the step floor  12  when the electric charger  200  lies on the step floor  12 . As described above, the recesses  96   a  in which the teeth  205  of the electric charger  200  are fitted respectively, are provided as the mount  96 , the recesses  96   a  being defined in the step floor  12  and being spaced from each other in the transverse directions of the vehicle  10 . Thus, the electric charger  200  is firmly held on the two-wheeled electric vehicle  10  even when the two-wheeled electric vehicle  10  is supported on the side stand  72  while being inclined to the vertical as shown in  FIG. 7 . 
         [0072]      FIG. 8  is a block diagram of an electric system of the two-wheeled electric vehicle  10 . Reference numerals shown in  FIG. 8  which are identical to those shown in  FIGS. 1 through 4  denote identical or equivalent parts. The two-wheeled electric vehicle  10  includes the main battery  18 , the DC-to-DC converter  82 , the auxiliary battery  80 , the electric motor  16 , the ECU  86 , the power drive unit  50 , and a contactor  300 . The electric charger  200  comprises a DC power supply  310  and a controller  311 . In  FIG. 8 , thick solid lines represent the flow of electric power, and thin solid lines represent the flow of signals. 
         [0073]    The main battery  18  comprises a battery module  304 , an SOC detector  306 , and a BMU (Battery Management Unit)  308 . The battery module  304  is made up of a plurality of battery cells. The SOC detector  306  detects the SOC (State Of Charge) of each of the battery cells. The SOC detector  306  has a shunt resistor and detects the SOC of each battery cell by detecting an electric current discharged from the battery cell and an electric current supplied to charge the battery cell. Alternatively, the SOC detector  306  may detect the SOC of each battery cell by detecting the voltage across the battery cell. The SOC detector  306  sends the detected SOC of each battery cell to the BMU  308 . Based on the SOC of each battery cell, the BMU  308  checks whether each battery cell is over-charged and over-discharged or not, and manages SOC information of each battery cell. The BMU  308  outputs the SOC information of each battery cell to the ECU  86 . 
         [0074]    The contactor  300  connects to the main battery  18 . The DC-to-DC converter  82  lowers the voltage of the battery module  304  that is supplied through the contactor  300 , and applies the lowered voltage to the auxiliary battery  80 , thereby charging the auxiliary battery  80 . The DC-to-DC converter  82  also applies the lowered voltage to the ECU  86 . The auxiliary battery  80  supplies its electric power to the BMU  308 . 
         [0075]    The ECU  86  controls various parts of the two-wheeled electric vehicle  10 . Based on the SOC information sent from the BMU  308 , the ECU  86  controls the discharging and charging of the battery module  304 . The power drive unit  50  has a PWM inverter which converts a direct current from the battery module  304  into three-phase alternating currents to energize the electric motor  16  according to a control signal from the ECU  86 . 
         [0076]    The DC power supply  310  has a DC-to-DC converter which converts AC electric power from the commercial power supply outlet into DC electric power according to a control signal from the controller  311 . The DC power supply  310  outputs the converted DC electric power to the contactor  300 . The controller  311  controls the voltage and current output from the DC power supply  310  according to a control signal from the ECU  86 . 
         [0077]    When the battery module  304  is charged, the contactor  300  supplies electric power output from the DC power supply  310  to the battery module  304  according to a control signal from the ECU  86 . When the SOC of the battery cells detected by the SOC detector  306  increases to a certain value, the contactor  300  disconnects the DC power supply  310  and the battery module  304  from each other, i.e., does not supply the electric power from the DC power supply  310  to the battery module  304 , according to a control signal from the ECU  86 . 
         [0078]    When the two-wheeled electric vehicle  10  is running, the contactor  300  supplies the electric power from the battery module  304  to the power drive unit  50  to energize the electric motor  16  according to a control signal from the ECU  86 . When the electric motor  16  produces regenerative energy, the contactor  300  charges the battery module  304  with the regenerative energy according to a control signal from the ECU  86 . 
         [0079]    In the first embodiment of the present invention, the two-wheeled electric vehicle  10  has been illustrated as a vehicle whose battery is charged by the electric charger  200 . However, the principles of the present invention are not limited to an electric charger for charging the battery of a two-wheeled electric vehicle, but are applicable to an electric charger for charging the battery of any vehicle. 
       2nd Embodiment 
       [0080]      FIGS. 9 and 10  are perspective views of an electric charger  400  according to a second embodiment of the present invention. 
         [0081]      FIG. 9  shows the electric charger  400  with a first charging electric cord  408  and a plug  412  stored therein, and  FIG. 10  shows the electric charger  400  with the first charging electric cord  408  and the plug  412  extended therefrom, i.e., not stored therein. The electric charger  400  has a storage case  402  housing a charger unit therein and a grip  404  on an upper end of the storage case  402 . The first charging electric cord  408  has an end connected to the charger unit and an opposite distal end connected to the plug  412 . The storage case  402  has a take-up recess  406  defined in an outer circumferential surface thereof, and the first charging electric cord  408  can be wound up in the take-up recess  406 . The storage case  402  has a hole  410  defined in the bottom of the take-up recess  406 , and the first charging electric cord  408  extends through the hole  410  out of the storage case  402 . As the first charging electric cord  408  extends through the hole  410  defined in the recess  406 , out of the storage case  402 , the user can easily and neatly place the first charging electric cord  408  into the take-up recess  406  in a take-up manner. 
         [0082]    The plug  412  is connected to the distal end of the first charging electric cord  408  through a support  414 . The plug  412  can be connected to a connector of a vehicle, such as the charging connector  20  (see  FIG. 5 ), which is connected to the main battery  18 . The storage case  402  has a plug cavity  416  defined therein for storing the plug  412 . The plug cavity  416  partly overlaps the take-up recess  406 . The plug cavity  416  is disposed at a position corresponding to a position of the plug  412  at the time when neatly winding of the first charging electric cord  408  around the take-up recess  406  is finished. Therefore, when the first charging electric cord  408  has been neatly wound up in the take-up recess  406  and the plug  412  is placed in the plug cavity  416 , the first charging electric cord  408  does not slack. The first charging electric cord  408  can thus be nearly and compactly stored in the take-up recess  406 . Also, as the plug  412  is housed in the plug cavity  416 , the plug  412  does not interfere with other objects stored in a storage box, etc. in which the electric charger  400  is placed, when the user carries the storage box. 
         [0083]    As indicated by the two-dot-and-dash lines in  FIG. 10 , the plug  412  is angularly movably supported on the support  414  by a hinge or a joint, not shown, for angular movement with respect to the first charging electric cord  408 . Therefore, the plug  412  can be oriented freely with respect to the first charging electric cord  408  and hence can be conveniently placed in the plug cavity  416 . The plug  412  that is angularly movable with respect to the first charging electric cord  408  can easily be connected to the connector of the vehicle. As shown in  FIG. 9 , the plug cavity  416  holds therein the plug  412  when it is oriented vertically toward the grip  404  in perpendicular to the longitudinal direction of the first charging electric cord  408 . 
         [0084]      FIG. 11  is an enlarged fragmentary cross-sectional view taken along line XI-XI of  FIG. 9 . As shown in  FIG. 11 , the plug  412  is received in the plug cavity  416 . The plug  412  has a magnet  418  disposed therein and the storage case  402  has a magnet  420  disposed on a wall which partly defines the plug cavity  416 . The magnets  418 ,  420  are positioned respectively in the plug  412  and the storage case  402  such that the magnets  418 ,  420  confront each other when the plug  412  is placed in the plug cavity  416 . Either one of the magnets  418 ,  420  may be replaced with a magnetic metal member. For example, the plug  412  may have a magnetic metal member, and the storage case  402  may have the magnet  420 . The magnets  418 ,  420  may be disposed in positions other than the positions illustrated in  FIG. 11  insofar as the plug  412  is firmly fixed in the plug cavity  416  and is hard to separate away from the plug cavity  416  under magnetic attraction thereof. 
         [0085]      FIG. 12  is a rear elevational view of the electric charger  400  according to the second embodiment of the present invention. The storage case  402  of the electric charger  400  has a hole defined therein below the take-up recess  406  for passage therethrough of a second charging electric cord (not shown) of AC 100 V, the hole being covered with a cap  422 . The storage case  402  houses therein the second charging electric cord beneath the take-up recess  406 . The second charging electric cord has a plug on its distal end for connection to a commercial power supply outlet. When the cap  422  is removed, the second charging electric cord with the plug can be pulled out of the storage case  402  through the hole. 
         [0086]      FIG. 13  is a side elevational view of the electric charger  400  according to the second embodiment of the present invention. As shown in  FIG. 13 , the electric charger  400  has a cooling fan for cooling the charger unit. The storage case  402  has an air outlet port  424  for discharging air from the cooling fan out of the storage case  402 . The air outlet port  424  is defined in a left side wall of the electric charger  400  as shown in  FIG. 9  and above the take-up recess  406 . 
         [0087]      FIG. 14  is a cross-sectional view taken along line XIV-XIV of  FIG. 9 . As shown in  FIG. 14 , the storage case  402  comprises the cooling fan, denoted by  428 , and the charger unit, denoted by  434 . The cooling fan  428  and the charger unit  434  are disposed above the take-up recess  406 . The charger unit  434  may have a circuit board for controlling the cooling fan  428 . The storage case  402  includes a spool  432  disposed in a storage space below the take-up recess  406 , with the second charging electric cord, denoted by  430 , wound around the spool  432  and disposed in the storage space. The storage case  402  may stores therein the second charging electric cord  430  in an automatic take-up manner. 
         [0088]    As described above, the electric charger  400  according to the second embodiment includes the take-up recess  406  defined in an outer circumferential surface of the storage case  402  for winding the first charging electric cord  408  around the storage case  402  and the plug cavity  416  defined in the storage case  402  for storing therein the plug  412  connected to the distal end of the first charging electric cord  408 . When the first charging electric cord  408  and the plug  412  are placed respectively in the take-up recess  406  and the plug cavity  416 , the electric charger  400  has a neat and smart appearance and makes itself compact as the first charging electric cord  408  and the plug  412  are snugly received respectively in the take-up recess  406  and the plug cavity  416 . As the plug  412  is housed in the plug cavity  416 , the plug  412  does not interfere with other objects stored in a storage box (not shown) in which the electric charger  400  is placed when the user carries the storage box. 
         [0089]    The electric charger  200  according to the first embodiment may be replaced with the electric charger  400  according to the second embodiment. In this case, an opening  436  which is defined by the storage case  402  and the grip  404  of the electric charger  400  may be regarded as the opening  202  of the electric charger  200  according to the first embodiment. In other words, the opening  436  may be hooked on the mount  96  of the two-wheeled electric vehicle  10 . The electric charger  400  according to the second embodiment may have teeth corresponding to the teeth  205  on its bottom, and the teeth of the electric charger  400  may be fitted respectively in the recesses  96   a  defined in the step floor  12  of the two-wheeled electric vehicle  10 , thereby installing the electric charger  400  on the two-wheeled electric vehicle  10 . 
         [0090]    Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.

Technology Category: 5