Patent Publication Number: US-2003221887-A1

Title: Electric wheel structure capable of being directly driven by power of motor

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to change of the power transmission structure of an electric vehicle and, more particularly, to simplification through common structure of the power transmission structure, the motor, and the wheel axle of a conventional electric vehicle, thereby enhancing the power transmission efficiency, lengthening the lifetime of use of the power system, and simplifying the maintenance.  
       BACKGROUND OF THE INVENTION  
       [0002] The power transmission structure, the motor for outputting power, and the wheel structure for bearing the vehicle weight are separate in a conventional electric vehicle. The extra power transmission structure is used to connect and transmit power between the motor and the wheel. The power transmission structure is exposed outside (e.g., U.S. Pat. Nos. 5,934,401 and 5,937,964). The power transmission structure usually uses a closed ringed belt or chain to transmit power. Combination with the power transmission structure inevitably causes difficult control of alignment accuracy of the X-axle (horizontal) and Y-axle (vertical) of fixing devices for the motor and the wheel. Difficult control of alignment accuracy and transmission structure of belt and chain will affect the power transmission efficiency and result in difficult control of transmission noise. Simultaneously, because the electric vehicle is mobile, the difference in the environment where it works is large. If the power transmission is contaminated by rainwater, dust, and mud, trouble in maintenance and lifetime of use of the power system will arise.  
       SUMMARY OF THE INVENTION  
       [0003] The present invention improves the power transmission structure of a conventional electric vehicle to simplify the power transmission structure and enhance the power transmission efficiency. Moreover, because the accuracy of the power transmission structure can be easily controlled, the power transmission noise can be controlled and the lifetime of use can be lengthened.  
       [0004] The present invention adds in a load bearing as a transmission interface between an axle and a wheel support frame of the wheel structure of a conventional electric vehicle. The outer diameter of the bearing directly contacts a bearing cavity installed at a support frame, and bears the load of the electric vehicle. The inner diameter of the bearing is passed by the axle of a wheel structure to correspondingly support the load and motion force of the electric vehicle and rotate with respect to the outer diameter of the bearing. One end of the wheel axle protrudes out of an end face of the support bearing. The protruding wheel axle end is connected with a power output end of the power transmission system to output power via the wheel axle to the wheel, thereby driving the electric vehicle to move.  
       [0005] The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0006] FIGS.  1 A˜ 1 B are perspective assembly views of a first embodiment of the present invention, wherein a torsion output mounting end  318  of an output portion  317  of a deceleration gear set comprises a unidirectional bearing  319 ;  
     [0007] FIGS.  2 A˜ 2 B are perspective assembly views of a second embodiment of the present invention, wherein a torsion output mounting end  318  of an output portion  317  of a deceleration gear set does not comprise a unidirectional bearing  319 ;  
     [0008] FIGS.  3 A˜ 3 B are perspective assembly views of a third embodiment of the present invention, wherein a central unidirectional bearing match hole  218  of a wheel body  211  comprises a unidirectional bearing  220 ;  
     [0009] FIGS.  4 A˜ 4 B are perspective assembly views of a fourth embodiment of the present invention, wherein a central unidirectional bearing match hole  218  of a wheel body  211  comprises a unidirectional bearing  220  and a wheel support bearing  219 ;  
     [0010] FIGS.  5 A˜ 5 B are perspective views of relative positions of a wheel structure  21  and a motor power transmission structure  31  of the present invention after they are separately assembled;  
     [0011]FIG. 6 is a perspective view of the present invention showing relative positions of a wheel structure  21  installed at an E-scooter and a motor power transmission structure  31 ; and  
     [0012]FIG. 7 is a perspective view of the present invention showing a wheel structure  21  and a motor power transmission structure  31  are separately assembled and then installed at an E-scooter. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0013] As shown in FIGS.  1  to  7 , the present invention provides an electric wheel structure  10  directly driven by power of motor, which comprises a wheel structure  21  and a motor power transmission structure  31 .  
     [0014] The wheel structure  21  comprises a wheel body  211 , a wheel axle  212 , a wheel support frame  214 , and a support frame bearing  215 . The support frame bearing  215  is installed at a bearing cavity  216  of the wheel support frame  214 . The wheel axle  212  passes through the inner diameter of the support frame bearing  215  and a central match hole  217  of the wheel body  211 . The wheel axle  212  at least has an end protruding out of an end face of the support frame bearing  215  as a mounting axle end  213 . The wheel axle  212  bears the vehicle load via the support frame bearing  215  and the support frame  214 . The mounting axle end  213  also corresponds to the motor power transmission structure  31  to synchronously rotate, thereby driving the wheel body  211  to rotate.  
     [0015] The motor power transmission structure  31  comprises a motor  311  and a deceleration gear set  312 . The motor  31  comprises a gear of a motor axle  313  for torsion output. The gear engages a gear at the input end of the deceleration gear set  312  to rotate correspondingly. The deceleration gear set  312  has an output portion  317  of reduced rotation speed but correspondingly enlarged torsion. The output portion  317  has a torsion output mounting end  318 , which is slipped with the mounting axle end  213  of the wheel axle  212 . The torsion output mounting end  318  and the mounting axle end  213  are mounted together for transmission output of torsion of the motor.  
     [0016] The torsion output mounting end  318  of the deceleration gear output portion  317  comprises a tightly installed unidirectional rotation bearing  319 . The mounting axle end  213  of the wheel axle  212  should be slipped into the inner diameter of the unidirectional rotation bearing  319 . The unidirectional rotation bearing  319  only transmits torsion output of the motor. But when the motor does not generate torsion or the rotation speed of the deceleration gear output portion  317  is lower than the rotation speed of the wheel  211 , the wheel axle  212  corresponding to the deceleration gear output portion  317  will idle and will not transmit torsion output of the motor.  
     [0017] The geometrical structure of the torsion output mounting end  318  of the deceleration gear output portion  317  corresponds to that of the mounting axle end  213 . The torsion output mounting end  318  and the mounting axle end  213  can be mounted and slipped together. Motor power is outputted via the mounted and slipped end to the wheel body  211 .  
     [0018] The wheel body  211  can comprise a wheel&#39;s unidirectional rotation bearing  220 , which is concentrically and tightly installed in the central unidirectional bearing hole  218  of the wheel body  211 . The wheel axle  212  passes through and is positioned at the inner diameter of the wheel&#39;s unidirectional rotation bearing  220 . Motor power is transmitted by the transmission structure to let the wheel axle  212  and the wheel&#39;s unidirectional rotation bearing  220  drive the wheel body  211  to rotate. But when the motor does not generate torsion or the rotation speed of the wheel axle  212  is lower than the rotation speed of the wheel  211 , the wheel axle  212  corresponding to the wheel body  211  will idle and will not transmit torsion output of the motor.  
     [0019] The wheel body  211  can comprise a wheel&#39;s unidirectional rotation bearing  220  and a wheel support rotation bearing  219 . The wheel&#39;s unidirectional rotation bearing  220  is concentrically and tightly installed in the central unidirectional bearing hole  218  of the wheel body  211 . The wheel support rotation bearing  219  is concentrically slipped at the outside end of the wheel&#39;s unidirectional rotation bearing  220 . The wheel axle  212  passes through the inner diameter of the wheel&#39;s unidirectional rotation bearing  220  and the inner diameter of the wheel support rotation bearing  220 . The wheel&#39;s unidirectional rotation bearing  220  only transmits torsion output of the motor. But when the motor does not generate torsion or the rotation speed of the wheel axle  212  is lower than the rotation speed of the wheel  211 , the wheel axle  212  corresponding to the wheel body  211  will idle and will not transmit torsion output of the motor.  
     [0020] The mounting axle end  213  of the wheel axle  212  and the torsion output mounting end  318  of the deceleration gear output portion  317  are tightly joined together.  
     [0021] The deceleration gear set  31  is a planetary gear module. The torsion output bearing gear is a solar gear  314 . The solar gear  314  equiangularly engages a plurality of planetary gears  315 . The planetary gears  315  then equiangularly engage inner gears  316  at the outer edge. The solar gear  314 , the planetary gears  315 , and the inner gears  316  equiangularly engage one another to decelerate the rotation speed and enlarge the torsion output of motor.  
     [0022] The wheel support frame  214  is installed between the wheel body  211  and the motor power transmission structure  31  to let the wheel body  211  be a unilaterally supported structure. Another wheel support frame  214  can also be installed at the other side of the wheel body  211  to let the wheel body  211  be a bilaterally supported structure. The geometrical structure of the wheel support frame  214  is not limited to a specific type, and can be varied according to the matching requirement of the whole structure of an electric vehicle.  
     [0023] The magnitude of outer diameter and the shape of the wheel body  211  are not limited. Moreover, it is not restricted that the wheel structure  21  be installed at any specific electric vehicle.  
     [0024] Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.