Title of Invention

BATTERY LAYOUT STRUCTURE IN ELECTRIC VEHICLE

Abstract

A battery layout structure in an electric vehicle is to be provided which can dissipate the heat generated from a battery to the exterior efficiently and which can prevent an increase in size of a front portion of the vehicle body. [Solving Means] The battery layout structure is applied to an electric vehicle having a downtube 4 extending backwardly downward in the longitudinal direction of the vehicle body from a head pipe 3 and also having batteries 74 for the supply of electric power to a motor as a power source, the batteries 74 being supported by a pair of battery holders 90 provided in the downtube. The battery holders 90 are formed integrally with the downtube 4, using the same material as the material of the downtube 4, and have respective extending portions 91 extending in the vehicular transverse direction.

Full Text

[Name of Document] Specification [Title of the Invention] Battery Layout Structure in Electric Vehicle [Technical Field] [0001] The present invention relates to a battery layout structure in an electric vehicle provided with a battery for the supply of electric power to a motor as a power source. [Background Art] [0002] There has been proposed an electric motorcycle having a downtube extending backwardly downward in the longitudinal direction of a body of the vehicle from a head pipe, with a resinous battery box bolted to the downtube, and a battery accommodated within the battery box for the supply of electric power to a motor as a power source (see, for example, Patent Document 1). In this type of an electric motorcycle, since the battery is disposed along the downtube, there accrues an advantage that it is possible to ensure an effective weight balance of the vehicle even when a plurality of relatively heavy batteries are mounted on the vehicle. [Patent Document 1] Japanese Patent No. 3069808 [Disclosure of the Invention] [Problem to be Solved by the Invention] [0003] In the conventional construction, however, since the battery box is made of resin, there is the possibility that the heat generated from the battery will be difficult to be dissipated to the exterior efficiently. Moreover, since the battery box is fixed to the downtube through a connecting member such as a battery bracket, a clearance is apt to occur between the downtube and the connecting member and also between the connecting member and the battery box. In this connection, an increase in size of a front portion of the vehicle body is to be prevented. [0004] Accordingly, it is an object of the present invention to provide a battery layout structure in an electric vehicle which can dissipate the heat generated from a battery to the exterior efficiently and which can prevent an increase in size of a front portion of the vehicle body. [Means for Solving the Problems] According to the present invention, for achieving the above-mentioned object, there is provided a battery layout structure in an electric vehicle having a downtube extending backwardly downward in the longitudinal direction of a body of the vehicle from a head pipe and a battery for the supply of electric power to a motor as a power source, the battery being supported by a battery holder provided in the downtube, wherein the battery holder is formed integrally with the downtube, using the same material as the material of the downtube, and has an extending portion extending in the transverse direction of the vehicle body. In this case, the battery may be supported at an end of the extending portion of the battery holder. [0006] In the present invention, the battery holder is formed integrally with the downtube using the same material as the material of the downtube, therefore, if the material is a metal superior in thermal conductivity, e.g. aluminum alloy, the heat generated from the battery is dissipated efficiently through the battery holder and the downtube. Moreover, since the battery holder has an extending portion extending in the vehicular transverse direction, the heat dissipating surface of the extending portion increases, thus permitting more efficient heat dissipation. Further, since the battery holder is integral with the downtube, in comparison with the case where the battery holder is fixed to the downtube through a connecting member, a wasteful clearance is not formed between the downtube and the connecting member or between the connecting member and the battery holder, whereby it is possible to prevent an increase in size of a front portion of the vehicle body. [0007] The extending portion of the battery holder may be formed with a rib. The rib may be formed in plural rows in a side view of the vehicle body. According to these constructions, since the area of heat dissipation is increased by the rib, a further heat dissipating effect can be expected. Besides, since the rib is formed in the extending portion, it is possible to enhance the rigidity of the downtube and hence of the entire frame. The extending portion of the battery holder may be extended forward of the vehicle body with respect to the position of the downtube and the rib may be formed in the forwardly extending portion. According to this construction, since the extending portion is extended forward of the vehicle body with respect to the position of the downtube, the extending portion becomes so much longer, and by forming the rib in the thus-lengthened extending portion, the area of the rib can be taken large and the heat dissipating efficiency can be so much improved. [0008] An intake port and an exhaust port may be formed in a cover member which covers the battery holder and the intake port may be formed so as to confront the battery. Further, fins may be formed on the surface of the battery holder opposed to the intake port formed in the cover member. According to these constructions, since a cover member which covers the battery holder is provided, it is possible to protect the battery. Besides, since an intake port is formed so as to confront the battery or fins are formed on the surface of the battery holder opposed to the intake port formed in the cover member, the battery cooling effect can be further enhanced. [Effect of the Invention] In the present invention, since the battery holder is formed integrally with the downtube using the same material as the material of the downtube and has an extending portion extending in the vehicular transverse direction, the heat generated from the battery is dissipated efficiently to the exterior through the battery holder and the downtube and an increase in size of a front portion of the vehicle body is prevented. [Best Mode for Carrying out the Invention] [0010] An embodiment of the present invention will be described hereinunder with reference to the accompanying drawings. Fig. 1 is a side view of a hybrid type scooter according to this embodiment. This scooter is driven by a hybrid power of both internal combustion engine and electric motor. In Fig. 1, the numeral 1 denotes the scooter. The scooter 1 includes a head pipe 3 which supports a shaft 2a of a steering handle (hereinafter referred to simply as "handle" ) 2 rotatably. A downtube 4 extending backwardly downward in the longitudinal direction of a body of the vehicle is connected to the head pipe 3 and an intermediate frame 5 branching left and right of the vehicle body and extending backward substantially horizontally is connected to a lower end of the downtube 4. A battery 125 for the supply of a controlling voltage of 12 volts to an engine 9 and lamps is disposed in a front portion of the intermediate frame 5 and a cross member 5a is mounted bridgewise between left and right rear portions of the intermediate frame 5. A pair of left and right rear frames 6 extending backward and obliquely upward of the vehicle body are connected to the cross member 5a. The head pipe 3, downtube 4, intermediate frame 5 and rear frames 6 constitute a body frame of the vehicle. [0011] An upper end of a front fork 7 is connected through a bottom bridge 37 to a lower end of the shaft 2a of the handle 2 which is supported by the head pipe 3, and a front wheel 8 is supported through an axle by a lower end of the front fork 7. A power unit 12 is connected to the rear frames 6 vertically swingably through a link mechanism 13. The power unit 12 includes the engine 9, an electric motor 10, and a belt type continuously variable transmission 11. A rear wheel 15 is connected to the power unit 12 through a reduction mechanism 14. A rear cushion 16 is mounted between a rear portion of the power unit 12 and rear portions of the rear frames 6. A lower end of the rear cushion 16 is pinned to the rear portion of the power unit 12, while an upper end of the rear cushion 16 is pinned to the rear portions of the rear frames 6. [0012] A rider seat 122 is disposed on top of the rear frames 6 and a receptacle space for a helmet, etc. is formed below the rider seat 122. Further, an inverter controller 23 as a driver circuit for the motor 10 and a control unit (ECU) 24 for controlling the engine 9 and a motor generator 10a (Fig. 2) are disposed on the rear frames 6. [0013] Next, a schematic configuration of the power unit 12 will be described below with reference to Fig. 2. The power unit 12 includes the engine 9 as a first power source, the motor generator 10a which not only functions as a starter for starting the engine 9 but also functions as a generator, the belt type continuously variable transmission 11 which converts the power of the engine 9 into a transmission gear ratio proportional to the engine speed and then transmits the power after the conversion to a rear wheel 15 as a driving wheel, a centrifugal clutch 4 0 as a speed-sensing type clutch disposed between the engine 9 and the continuously variable transmission 11 to cut off the transfer of power, a one-way clutch 44 which transmits power from the continuously variable transmission 11 to the rear wheel 15 but does not transmit power from the rear wheel 15 to the continuously variable transmission 11, the reduction mechanism 14 located between a rear wheel 15-side output portion (driven shaft 60) of the one-way clutch 44 and an axle 68 of the rear wheel 15 to decelerate the output to be transmitted to the rear wheel 15, the electric motor 10 connected to an input side of the reduction mechanism 14 and functioning not only as a motor as a second power source but also as a generator, the inverter controller 23 for controlling both the electric motor 10 and the motor generator 10a, and the control unit 24 for controlling both the inverter controller 23 and the engine 9. [0014] The power unit 12 basically has two drive systems. One of the drive systems transmits the power of the engine 9 to the rear wheel 15 through the centrifugal clutch 40, continuously variable transmission 11, one-way clutch 44, driven shaft 60 and reduction mechanism. The other drive system transmits the power of the electric motor 10 to the rear wheel 15 through the driven shaft 60 and the reduction mechanism 14. A battery 74 is connected to both motor generator 10a and electric motor 10. When the motor generator 10a and the electric motor 10 function as a starter or motor, they are supplied with electric power from the battery 74, while when the motor generator 10a and the electric motor 10 function as a generator, their regenerated power is charged to the battery 74. [0015] The engine 9 is constructed so as to introduce and burn an air-fuel mixture. A throttle valve 117 for controlling the amount of air is disposed pivotably within the intake pipe 116. The throttle valve 117 is adapted to turn in accordance with the amount of operation of a throttle grip which the rider operates. In Fig. 2, the numeral 85 denotes a throttle angle sensor provided in the throttle grip. A fuel injector 118 and a negative pressure sensor for detecting an internal negative pressure of the intake pipe 116 are disposed between the throttle valve 117 and the engine 9. Fig. 3 is a sectional view of the power unit 12. As noted above, the power unit 12 includes the engine 9 as the first power source. In the engine 9, a piston 25 is slidably received within a cylinder 27 of a cylinder block 26. A connecting rod 24 is connected to the piston 25 and a crank shaft 22 is connected to the connecting rod 24. The cylinder block 2 6 is disposed so that the axis of the cylinder 27 becomes substantially horizontal, and a cylinder head 28 is fixed to the head of the cylinder block 26 so as to close one end of the cylinder 27. A combustion chamber 2 0a for burning the air-fuel mixture is formed between the cylinder head 28 and the piston 25. [0017] A valve (not shown) for controlling the intake or exhaust of the air-fuel mixture to or from the combustion chamber 20a, as well as a spark plug 29, are disposed in the cylinder head 28. Opening and closing of the aforesaid valve are controlled by rotation of a cam shaft 3 0 supported in the cylinder head 28. The cam shaft 30 is provided on one end side with a driven sprocket 31, and an endless cam chain 33 is stretched between the driven sprocket 31 and a driving sprocket 32 mounted on one end of the crank shaft 22 so as to be entrained on both sprockets. The cam shaft 30 is interlocked with rotation of the crank shaft 22 through the cam chain 33. A water pump 34 for cooling the engine 9 is mounted on one end of the cam shaft 30. A rotary shaft 35 of the water pump 34 is mounted so as to rotate integrally with the cam shaft 30. Therefore, when the cam shaft 3 0 rotates, the water pump 34 is actuated with the rotational force of the cam shaft. [0018] The crank shaft 22 is supported in a crank case 48. A stator case 4 9 is connected to the right side in the vehicular transverse direction of the crank case 4 8 and the motor generator 10a is accommodated within the stator case 49. The motor generator 10a is what is called an outer rotor type motor and its stator is constituted by a coil 51 which comprises teeth 50 fixed to the stator case 49 and a conductor wound round the teeth 50. On the other hand, an outer rotor 52 is fixed to the crank shaft 22 and has a generally cylindrical shape which covers the outer periphery of the stator. A magnet 53 is fixed to the inner periphery surface of the outer rotor 52. A centrifugal fan 54 for cooling the motor generator 10a is attached to the outer rotor 52. When the centrifugal fan 54 rotates in synchronism with the crank shaft 22, the outside air is introduced from a cooling air intake port formed in a side face 55a of a cover 55 of the stator case 49. [0019] A left end portion of the crank shaft 22 projects in the vehicular transverse direction from the crank case 48 and a driving pulley 58 of the continuously variable transmission 11 is attached to the projecting left end portion of the crank shaft 22 through the centrifugal clutch 40. The continuously variable transmission 11 includes, in addition to the driving pulley 58, a driven pulley 62 mounted through the one-way clutch 44 to a driven shaft 60 which is disposed so as to have an axis parallel with the crank shaft 22, and an endless V belt 63 which transmits a rotational power from the driving pulley 58 to the driven pulley 62. [0020] As shown in Fig. 4, the driving pulley 58 is mounted on the crank shaft 22 rotatably through a sleeve 58d and includes a fixed driving pulley half 58a fixed onto the sleeve 58d and a movable driving pulley half 58c mounted slidably in the axial direction of the sleeve 5 8d but unrotatably in the circumferential direction. A weight roller 58b is secured to the movable driving pulley half 58c to displace the pulley half 58c toward the fixed driving pulley half 58a in accordance with a centrifugal force. The driven pulley 62 includes a fixed driven pulley half 62a mounted on the driven shaft 60 so as to be unslidable in the axial direction of the driven shaft 6 0 but rotatable in the circumferential direction and a movable driven pulley half 62b mounted axially slidably on a boss portion 62c of the fixed driven pulley half 62a. On a back side (on the left side in the vehicular transverse direction) of the movable driven pulley half 62b is provided a spring 64 which urges the movable driven pulley half 62b constantly toward the fixed driven pulley half 62a. [0021] The V belt 63 is entrained on a belt groove of a generally V-shaped section formed between the fixed driving pulley half 58a and the movable driving pulley half 58c and a like belt groove formed between the fixed driven pulley half 62a and the movable driven pulley half 62b. [0022] In the continuously variable transmission 11, when the number of revolutions of the crank shaft 22 increases, a centrifugal force acts on the weight roller 58b in the driving pulley 58 and the movable driving pulley half 58c slides toward the fixed driving pulley half 58a. At this time, the movable driving pulley half 58c approaches the fixed driving pulley half 5 8a by an amount corresponding to the above slide movement and hence the groove width in the driving pulley 58 decreases, so that the position of contact between the driving pulley 58 and the V belt 63 shifts radially outside the driving pulley 58 and hence the winding diameter of the V belt 63 increases. Consequently, in the driven pulley 62, the groove width defined by both fixed driven pulley half 62a and movable driven pulley half 62b increases. That is, in accordance with the number of revolutions of the crank shaft 22, the winding diameter (transfer pitch diameter) of the V belt 63 changes continuously and the transmission gear ratio changes automatically and steplessly. [0023] The centrifugal clutch 40 is mounted on an end portion of the crank shaft 22, the said end portion being located on the left side of the vehicle body and extending through the fixed driving pulley half 58a in the continuously variable transmission 11. The centrifugal clutch 4 0 includes a cup-like outer case 4 0a fixed to the sleeve 58d, an inner plate 40b fixed to the left end portion of the crank shaft 22 extending through the outer case 4 0a, a shoe 4 0d secured to a surface of the inner plate 40b which surface faces the interior of the outer case 40a, the shoe 40d being mounted so as to face radially outward through a weight 40c, and a spring 40e which urges the shoe 40d radially inward. According to this construction, the inner plate 4 0b, the weight 40c and the shoe 40d constitute an inner rotor of the centrifugal clutch 40, while the outer case 40a constitutes an outer rotor. The centrifugal fan 54 is attached to an outer end face of the inner plate of the centrifugal clutch 40. The outside air introduced from an intake port 59a of a transmission case 59 is allowed to flow into the case 59 by a blow-off action of the centrifugal fan 54. [0024] With a balance between the centrifugal force of the weight 4 0c and the biasing force of the spring 4 0e, the centrifugal clutch 40 makes and breaks the supply of power. When the rotational speed of the crank shaft 22 is lower than a preset value (e.g., 300 rpm) , the transfer of power is cut off by the biasing force of the spring 40e. Then, when the rotational speed of the crank shaft 22 exceeds the above preset value, the centrifugal force of the weight 4 0c overcomes the biasing force of the spring 40e, so that the weight 40e moves radially outwards, whereby the shoe 4 0d is pressed against the inner periphery surface of the outer case 40a. At this time, a frictional slide occurs between the shoe 4 0d and the outer case 4 0a and in the meantime the transfer of power is performed gradually. As a result, the rotational force of the crank shaft 2 2 is transmitted to the sleeve 58d through the centrifugal clutch 40, whereby the driving pulley 58 fixed to the sleeve 58d is operated. [0025] The one-way clutch 44 includes a cup-like outer clutch 44a, an inner clutch 44b inserted coaxially into the outer clutch 44a, and a roller 44c which permits the transfer of power in only one direction from the inner clutch 44b to the outer clutch 44a. The outer clutch 44a also serves as an inner rotor body in the electric motor 10 and is constituted by the same member as the inner rotor body. The inner periphery portion of the inner clutch 44b and the left end of the boss portion 62c of the fixed driven pulley half 62a are splined to each other. [0026] The one-way clutch 44 transmits the power of the engine 9 which has been transmitted to the driven pulley 62 in the continuously variable transmission 11, to the rear wheel 15 through the driven shaft 60 and the reduction mechanism 14, but does not transmit the power which has been inputted from the rear wheel 15 through the reduction mechanism 14 and the driven shaft 60, to the continuously variable transmission 11. Therefore, when the rider walks while pushing the vehicle or in regenerating operation, the power on the rear wheel 15 side merely causes the outer clutch 44a to race with respect to the inner clutch 44b and is not transmitted to the continuously variable transmission 11 and the engine 9. [0027] As shown in Fig. 3, the reduction mechanism 14 includes an intermediate shaft 73 which is supported in parallel with both driven shaft 60 and axle 68 of the rear wheel 15, a pair of first reduction gears 71 formed respectively at a right end position of the driven shaft 60 and at a central position of the intermediate shaft 73, and a pair of second reduction gears 72 formed at left end positions of the intermediate shaft 73 and the axle 68. In the reduction mechanism 14, the rotation of the driven shaft 60 is reduced to a predetermined reduction ratio and is then transmitted to the axle 6 8 of the rear wheel 15 which is supported in parallel with the driven shaft 60. [0028] As shown in Fig. 4, the electric motor 10 is an inner rotor type motor using the driven shaft 60 as a motor output shaft. The inner clutch 44b described above constitutes an inner rotor body of an inner rotor 80. A stator 83 of the electric motor 10 is fixed to the inside of the transmission case 5 9 through a stator case 83a and teeth 83b with a coil 83c wound thereon are provided in the stator 83. The outer clutch 44a is formed in the shape of a cup and a boss portion 80b projected centrally of the outer clutch 44a is splined to the driven shaft 60. A magnet 8 0c is mounted to the outer periphery surface on an opening side of the outer clutch 44a so as to confront the teeth 83b of the stator 83. A plurality of to-be-detected pieces 82 to be detected by a rotor sensor 81 attached to an inner wall 59A of the transmission case 59 are attached to the outer periphery surface on a bottom side of the outer clutch 44a. [0029] The electric motor 10 not only functions as a motor which assists starting and also assists the output of the engine 9 but also functions as a generator which converts the rotation of the driven shaft 6 0 into electrical energy and stores the regenerated power in the battery 74 shown in Fig. 2. [0030] Next, a description will be given below about a support structure for supporting the battery 74 to the vehicle. Fig. 5 is a perspective view of a principal front portion of the scooter 1 as seen the left rear side and Fig. 6 is a side view thereof. As the battery 74 there are provided a plurality of, for example, columnar nickel hydrogen batteries. As shown in Fig. 5, the plural batteries 74 are arranged in a row on both left and right side in the vehicular transverse direction with the downtube 4 therebetween. The downtube 4 is made of aluminum alloy. As shown in Fig. 7, the downtube 4 has a generally an angular U-shaped section and includes a front wall portion 4a and a pair of side wall portions 4b. Battery holders 90 extending integrally in the vehicular transverse direction are formed respectively at lower edges 4c of the pair of side wall portions 4b, using the same material as the material of the downtube 4. The battery holders 90 are respectively provided with extending portions 91 which are integrally contiguous to the lower edges 4c of the side wall portions 4b. As shown in Fig. 5, based on portions 191 which are contiguous to nearly the whole area of the lower edges 4c, the extending portions 91 are curved substantially symmetrically in the vehicular transverse direction and extend so as to expands the skirts, with battery receptacles 92 (see Fig. 7) being integrally formed at ends of the extending portions 91, the battery receptacles 92 being declined backward from above to receive the batteries 74 therein. [0032] Each battery receptacle 92, which is formed using the same material as the material of the downtube 4, is provided an upper battery receptacle portion 92a and a lower battery receptacle portion 92b, as shown in Figs. 5 and 6. Of the battery receptacle portions 92a and 92b, the lower battery receptacle portion 92b is integrally formed at an end of the extending portion 91, while the upper battery receptacle portion 92a is bent from an upper end of the lower battery receptacle portion 92b and extends vertically upward. [0033] As shown in Fig. 8, the lower battery receptacle portion 92b extends wider in the vehicular transverse direction than the upper battery receptacle portion 92a and is positioned distantly away from the head pipe 3. The spacing between the left and right lower battery receptacle portions 92b is set larger than the width of the front fork 7. According to this layout, even if the battery receptacles 92 are positioned close to the front side of the vehicle body, there is no fear of interference of the bent portions of the battery receptacles 92 with the bottom bridge 37 (see Fig. 1). Thus, it becomes possible to dispose the battery receptacles 92 at positioned close to the front side of the vehicle body along a leg shield 129. [0034] As shown in Fig. 8, a pair of recesses 138 (see Fi 6) are formed in the extending portions 91 of the battery holders 90 on both sides of the downtube 4 and symmetrically left and right. The top of the front fork 7, i.e., the position of the bottom bridge 37, corresponds to the recesses 138. According to this layout, when the battery receptacles 92 are disposed at positions close to the front side of the vehicle body, the bottom bridge 37 is received within the two recesses 13 8 and hence never comes into abutment against the extending portions 91. [0035] According to this construction, as is seen also from Fig. 9, plural batteries 74 can be arranged efficiently in the wide area from around the head pipe 3 to around the downtube 4 and therefore sufficient electric power can be fed to the driving motor in the electric motorcycle. Since the batteries 74 are arranged along the bent shape of the head pipe 3 and downtube 4 and near the left and right ends of the leg shield 129 to avoid interference with the front fork 7, it is possible to position the batteries 74 fully close to the front side of the vehicle body. As a result, a space margin can be created around the rider's legs. As shown in Fig., 7, plural batteries 74 and bandlike holders 93 for holding both ends of the batteries 74 are accommodated within each battery receptacle 92, and a battery cover 94 is applied to cover them. More specifically, as shown in Fig. 10, the bottom of each battery receptacle 92 is formed with a portion 92c comprising a series of semicircular waves, and the batteries 74 are accommodated in the portion 92c. Then, a battery cover 94 comprising a series of semicircular waves like the bottom of the battery receptacle 92 is applied to the batteries. A certain gap is formed between the batteries 74 and each of the portions 92c and 94c comprising a series of semicircular waves to prevent interference. [0037] The battery receptacle 92 and the battery cover 94 are provided with mounting bosses 181 and 182, respectively. After the battery cover 94 has been applied so as to cover the batteries 74 and the band-like holders 93, the mounting bosses 181 and 182 are aligned with each other and are fixed together with clamping screws 183. In this case, the battery cover 94 may be formed as a separate member or may be formed integrally by molding so as to include a hinge portion. In the following description, a battery assembly comprising the plural batteries 74 accommodated in the upper receptacle portion 92a is designated an upper battery assembly 127, while a battery assembly comprising the plural batteries 74 accommodated in the lower battery receptacle portion 92b is designated a lower battery assembly 128. [0038] As shown in Fig. 5, the front wall portion 4a of the downtube 4 is formed in such a manner that the width W thereof becomes gradually larger from an upper end portion 4d joined to the head pipe 3 toward a lower end portion 4e which extends backwardly downward. Therefore, the extending portion 91 of each battery holder 90 is larger in its projection length near the upper end portion 4d of the downtube 4 than in its projection length near the lower end 4e of the downtube. A center cover 141 is disposed at a midway position in the longitudinal direction of the front wall portion 4a and it is secured to a retaining piece 133 extending integrally from the front wall portion 4a of the downtube 4. A conductor unit 134 is disposed inside the center cover 141. The conductor unit 134 is secured to the front wall portion 4a of the downtube 4 with plural set-screws 140. As shown in Fig. 11, a fuse 149 and a relay unit 151 connected in series to the fuse 14 9 are accommodated within the conductor unit 134. The upper and lower battery assemblies 127, 128 arranged left and right of the vehicle body are connected together in series and thereafter a positive-side cord 152 drawn out from the relay unit 151 and a negative-side cord 153 drawn out from the lower battery assembly 128 located on the left side in the figure are connected with each other through a coupler 154. [0040] As shown in Fig. 7, the leg shield 129 (cover member) constituting a part of a front cowl 15 0 (see Fig. 1) which covers the front side of the vehicle body is disposed in front of the vehicle body, and plural intake ports 143 are formed in both end portions in the vehicular transverse direction of the leg shield 129 so as to confront substantially the whole area in the longitudinal direction of the lower battery receptacle portions 92b. Plural fins 143a for controlling the wind direction are integrally formed near the intake ports 143. The plural fins 143a are formed so that the air flowing from the vehicular front side can be introduced into the leg shield 129 from the vehicular center side toward the outside in the vehicular transverse direction. Outer surfaces of the lower battery receptacle portions 92b are positioned in opposition to the intake ports 143 and plural fins 92c are integrally formed on the outer surfaces (surfaces) of the lower battery receptacle portions 92b so as to permit dissipation of the heat from the batteries 74. [0041] An inner cover (rear cover) 142 is disposed behind the upper and lower battery assemblies 127, 128 so as to cover the battery assemblies from the rear side of the vehicle body. Air exhaust ports 144 are formed in both end portions in the vehicular transverse direction of the inner cover 142 (cover member). [0042] According to this construction, with travel of the scooter 1, air is guided by the plural fins 143a and flows into the leg shield 12 9 through the intake port 143, as indicated with arrows W. The air flows while cooling the outer surfaces of the lower battery receptacle portions 92b and the plural fins 92c and is discharged through the exhaust ports 144 while rolling up therein the air present around the downtube 4 and the extending portions 91, as indicated with arrows Z. [0043] In this embodiment, since the battery holders 90 are formed integrally with the downtube 4 using aluminum alloy superior in thermal conductivity which is the same material as the material of the downtube 4, the heat generated from the batteries 74 is dissipated efficiently to the exterior through the battery holders 90 and the downtube 4. Moreover, since the battery holders 90 have the respective extending portions 91 extending largely in the vehicular transverse direction and the extending portions 91 are curved to increase the area, the heat dissipating area of each extending portion 91 increases and the dissipation of heat can be done more efficiently. The battery holders 90 are formed integrally with the downtube 4, so in comparison with the conventional structure wherein the battery holders 90 are fixed to the downtube 4 through connecting members, any wasteful clearance does not occur between the downtube 4 and the connecting members or between the connecting members and the battery holders 90, whereby an increase in size of the front portion of the vehicle body is prevented. [0044] Since the leg shield 129 and the inner cover 142 are disposed respectively before and behind the battery holders 90 so as to cover the battery holders, it is possible to protect the batteries 74. Further, the intake ports 143 are formed in the leg shield 129, the exhaust ports 144 are formed in the inner cover 142, and the fins 92c are formed on the surfaces of the battery holders 90 opposed to the intake ports 143. Consequently, the battery cooling effect can be further enhanced. [0045] Figs. 12 (a) and 12 (b) illustrate another embodiment of the present invention. In this embodiment, extending portions 91 of battery holders 90 are extended to the front side of the vehicle body with respect to the position of the downtube 4 and ribs 95 are integrally formed respectively in the extending portions 91 extending to the front side of the vehicle body, using the same material as the material of the extending portions 91. The ribs 95 extend between the downtube 4 and the battery receptacles 92 and each comprise a front rib 95a and a rear rib 95b projecting behind the associated extending portion 91. The height of each rib 95 is set such that, in terms of the height H including the extending portion 91, the height H on the downtube 4 side is the largest and the height H becomes gradually smaller toward the associated battery receptacle 92. Each rib 95 is formed so as to extend within a horizontal plane. Preferably, as shown in Fig. 12b, plural ribs are formed in parallel and spacedly at suitable intervals of L. Such ribs 95 are provided in plural rows in a side view of the vehicle body. [0046] According to this construction, since the area of heat dissipation is increased by the ribs 95, a further heat dissipating effect can be expected. Besides, since the ribs 95 are provided in the extending portions 91, it is possible to enhance the rigidity of the downtube 4 and hence of the entire frame. In this construction, by extending the extending portions to the front side of the vehicle body with respect to the position of the downtube 4, the extending portions 91 become so much longer, and by forming the ribs 95 on the thus-lengthened extending portions 91, the area of the ribs 95 can be taken large and the heat dissipating efficiency can be so much improved. [0047] Although the present invention has been described by way of the above embodiments, it is evident that the present invention is not limited thereto. For example, although in the above embodiments the present invention is applied to a two-wheel scooter, the present invention is also applicable to three- and four-wheel vehicles insofar as the vehicles have a frame member (corresponding to the downtube) extending backward and obliquely downward from a head pipe. Further, the present invention is applicable not only to hybrid vehicles but also to electric vehicles wherein the wheels are driven by only an electric motor. [Brief Description of the Drawings] [0048] [Fig. 1] Fig. 1 is a side view of an electric vehicle in a first embodiment of the present invention. [Fig. 2] Fig. 2 is a functional block diagram showing a schematic system configuration of the vehicle of Fig. 1. [Fig. 3] Fig. 3 is a sectional view of a power unit used in the vehicle of Fig. 1. [Fig. 4] Fig. 4 is a partial enlarged view of Fig. 3. [Fig. 5] Fig. 5 is a perspective view showing a principal portion of a front portion of a vehicle body as seen from the left rear side. [Fig. 6] Fig. 6 is a side view of the front portion of the vehicle body. [Fig. 7] Fig. 7 is a sectional view taken on line B-B in Fig 1. [Fig. 8] Fig. 8 is a front view of the front portion of the vehicle body. [Fig. 9] Fig. 9 is a rear view of the front portion of the vehicle body. [Fig. 10] Fig. 10 is a sectional view taken on line A-A in Fig. 9. [Fig. 11] Fig. 11 is a rear view of the front portion of the vehicle body with covers removed. [Fig. 12] Fig. 12(a) is a sectional view of a front portion of a vehicle body according to a modification and Fig. 12(b) is a sectional view of an extending portion. [Description of Reference Numerals] [0049] 1 scooter 3 head pipe 4 downtube 74 battery 90 battery holder 91 extending portion 92 battery receptacle 92a upper battery receptacle portion 92b lower battery receptacle portion 95 rib 129 leg shield (cover member) 142 inner cover (cover member) 143 intake port 144 exhaust port [Name of Document] Claims [Claim 1] A battery layout structure in an electric vehicle having a downtube extending backwardly downward in the longitudinal direction of a body of the vehicle from a head pipe and a battery for the supply of electric power to a motor as a power source, said battery being supported by a battery holder provided in said downtube, wherein said battery holder is formed integrally with said downtube, using the same material as the material of the downtube, and has an extending portion extending in the transverse direction of the vehicle body. [Claim 2] The battery layout structure in an electric vehicle according to claim 1, wherein said battery is supported at an end of the extending portion of said battery holder. [Claim 3] The battery layout structure in an electric vehicle according to claim 1 or claim 2, wherein the extending portion of said battery holder is formed with a rib. [Claim 4] The battery layout structure in an electric vehicle according to claim 3, wherein said rib is formed in plural rows in a side view of the vehicle body. [Claim 5] The battery layout structure in an electric vehicle according to claim 3 or claim 4, wherein the extending portion of said battery holder is extended forward of the vehicle body with respect to the position of said downtube and said rib is formed in said forwardly extending portion. [Claim 6] The battery layout structure in an electric vehicle according to any of claims 1 to 5, wherein an intake port and an exhaust port are formed in a cover member which covers said battery holder, said intake port being formed so as to confront said battery. [Claim 7] The battery layout structure in an electric vehicle according to claim 6, wherein fins are formed on the surface of said battery holder opposed to said intake port formed in said cover member.

Documents:

1725-CHE-2005 AMENDED PAGES OF SPECIFICATION 09-12-2011.pdf

1725-CHE-2005 AMENDED CLAIMS 09-12-2011.pdf

1725-CHE-2005 CORRESPONDENCE OTHERS 13-08-2012.pdf

1725-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 09-12-2011.pdf

1725-CHE-2005 FORM-3 09-12-2011.pdf

1725-CHE-2005 OTHER PATENT DOCUMENT 09-12-2011.pdf

1725-CHE-2005 POWER OF ATTORNEY 09-12-2011.pdf

1725-CHE-2005 CORRESPONDENCE OTHERS 13-06-2012.pdf

1725-che-2005-abstract.pdf

1725-che-2005-claims.pdf

1725-che-2005-correspondnece-others.pdf

1725-che-2005-description(complete).pdf

1725-che-2005-drawings.pdf

1725-che-2005-form 1.pdf

1725-che-2005-form 3.pdf

1725-che-2005-form 5.pdf

1725-che-2005-others document.pdf

abs-1725-che-2005.jpg