Abstract:
The present invention directly utilizes a transmission device as a hub of a wheel to prevent falling off a roller chain and be kept from annoying sounds out of rustiness while having a simple structure, a light weight, a small size and a steady transmission.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to an assembly method of use; more particularly, relates to directly utilizing a transmission device as a hub of a wheel while having a simple structure, a light weight, a small size and a steady transmission.  
       DESCRIPTION OF THE RELATED ARTS  
       [0002]     Transmission devices according to prior arts can be divided into two categories. A transmission device from one of the categories, as shown in  FIG. 9 , can comprise a small gear  73  deposed at a side of an axle  72  which is at the center of a wheel  71  of a vehicle  7 ; a driving motor  75  which is located at a proper place of the vehicle  7  and is comprised with a big gear  74 ; and a roller chain  76  which is being circled around the big gear  74  and the small gear  73  to connect both. When the driving motor  75  rolls, the big gear  74  is jointly rolled to roll the roller chain  76  which rolls the small gear  73  as well to roll the wheel  71 .  
         [0003]     A transmission device from the other category, as shown in  FIG.10 , can comprise a small gear  73  deposed at a side of an axle  72  which is at the center of a wheel  71  of a vehicle  7 ; a motor  77  which is deposed at a place of the vehicle  7  near the wheel  71 ; and a transmitting gear  79  which is engaged with the small gear  73  on the axle  78  of the motor  77 . When the motor  77  is powered by an outside electric power source to roll the axle  78 , the transmitting gear  79  is rolled to roll the small gear  73  so that the wheel  71  is engaged to roll as well.  
         [0004]     Although the above wheel structures for transmission devices can roll the wheel  71 , the transmitting methods with the coordination of the big and the small gears  74 , 73  and the roller chain  76  is apt to make the roller chain  76  fall off while the roller chain  76  needs to be oiled periodically to be kept from annoying sounds out of rustiness. Because the transmission is done by rolling the small gear  73  which is engaged with the roller chain  79  on the axle  79  of the motor  77 , abrasion happens between the roller chain  79  and the small gear  73  so that a striping-off and a speed error may happen between the roller chain  79  and the small gear  73 . In addition, the above wheel structures are complex and add weight to the vehicle  7  so that the prior arts do not fulfill users&#39; requests on actual use.  
       SUMMARY OF THE INVENTION  
       [0005]     Therefore, the main purpose of the present invention is to provide a transmission device to be used as a hub of a wheel while having a simple structure, a light weight, a small size and a steady transmission.  
         [0006]     To achieve the above purpose, the present invention is an assembly method of use for an electric wheel structure, comprising a wheel and a transmission device which is comprised with a sensor unit and is set at the center of the wheel. Therein, the transmission device comprises a case fixed on the inner end surface of the wheel; an axle of movability penetrates the case at the center; a coreless wound stator is deposed on the axle  22  and is connected with a coil for obtaining an outside power source; a collar plate is deposed in the case and is respectively corresponding to each end surface of the core less wound stator; a permanent magnet corresponding to the coreless wound stator is deposed on the collar plate; and the sensor unit is to sense the state of the magnetic pole of the core less wound stator.  
     
    
     BRIEF DESCRIPTIONS OF THE DRAWINGS  
       [0007]     The present invention will be better understood from the following detailed descriptions of the preferred embodiments according to the present invention, taken in conjunction with the accompanying drawings, in which  
         [0008]      FIG. 1  is a perspective view according to a preferred embodiment of the present invention;  
         [0009]      FIG. 2  is an explosive view of a first preferred embodiment of a transmission device according to the present invention;  
         [0010]      FIG. 3  is a cross-sectional view of the first preferred embodiment of a transmission device according to the present invention;  
         [0011]      FIG. 4  is a cross-sectional view of a second preferred embodiment of a transmission device according to the present invention;  
         [0012]      FIG. 5  is a perspective view showing a sensor unit for back electromotive force according to another preferred embodiment of the present invention;  
         [0013]      FIG. 6  is a view of an assembly according to the present invention;  
         [0014]      FIG. 7  is a view of an open loop control according to the present invention;  
         [0015]      FIG. 8  is a view of a close loop control according to the present invention;  
         [0016]      FIG. 9  is a perspective view according to a prior art; and  
         [0017]      FIG. 10  is a perspective view according to an other prior art. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     The following descriptions of the preferred embodiments are provided to understand the features and the structures of the present invention.  
         [0019]     Please refer to  FIG. 1  till  FIG. 5 , which are a perspective view of a preferred embodiment, an explosive view of a first preferred embodiment of a transmission device, cross-sectional views of a first and a second preferred embodiments of a transmission device, and a perspective view of another preferred embodiment showing a sensor unit for back electromotive force, according to the present invention. As shown in the figures, the present invention is an assembly method of use for an electric wheel structure, comprising obtaining a wheel  1  and a transmission device  2  with a sensor unit  3 , where the transmission device  2  can be used directly as a hub for the wheel  1  while having a simple structure, a light weight, a small size and a steady transmission.  
         [0020]     Therein, the transmission device  2  is deposed at center of the wheel  1 ; the transmission device  2  comprises a case  21  fixed on the inner end surface of the wheel  1 ; an axle  22  of movability penetrates the case  21  at the center; a bearing  221 , 221   a  is located respectively between the case  21  and each end of the axle  22 ; a coreless wound stator  23  is deposed on the axle  22  and is connected with a coil  231  for obtaining an outside power source; a collar plate  24 , 24   a  is deposed in the case  21  and is respecttively corresponding to each end surface of the coreless wound stator  23 ; a permanent magnet  241  corresponding to the coreless wound stator  23  is deposed on one collar plate  24 (as shown in  FIG. 4 ), or two permanent magnets  241 , 241   a  on both collar plates  24 , 24   a  (as shown in  FIG. 2  and  FIG. 3 ), to keep a shortest magnetic circuit to the axle; and, the transmission device  2  can be connected to a control unit  4  so that a loop is formed to control the rotation speed of the transmission device  2 .  
         [0021]     The sensor unit  3  can be set on the coreless wound stator  23  (as shown in  FIG. 3  and  FIG. 4 ) for sensing the state of the magnetic pole of the coreless wound stator  23  which is corresponding to the permanent magnet  241 (, 241   a ). The sensor unit can be a positioning sensor, such as a Hall element or a photo positioning sensor. The inverter  5  is connected to the sensor unit  3  to obtain the state of the magnetic pole of the coreless wound stator  23  sensed by the sensor unit  3  to control the field commutating time of the coreless wound stator  23 . Or, the sensor unit  3   a  can sense a commutation of a coreless wound stator  23  by a back electromotive force (as shown in  FIG. 5 ); and an inverter  5  is comprised with a detecting unit  51  to be informed of the back electromotive force. Accordingly, a novel assembly method of use for an electric wheel structure is obtained.  
         [0022]     Please refer to  FIG. 3  and  FIG. 6 , which are a cross-sectional view of a transmission device and a view of an assembly, according to the first preferred embodiment of the present invention. As shown in the figures, when assembling, a transmission device  2  fixed in a wheel  1  can be set on a supportive frame  61  of a vehicle  6  and a coil  231  of the transmission device  2  is connected to an electric power source  62  of the vehicle  6  so that the vehicle  6  having the wheel  1  and the transmission device  2  is assembled. When operating, a power from the electric power source  62  is applied to the transmission device  2  where a coreless wound stator  23  is kept being commutated according to a sensor unit  3  to continuously produce repulsive phases to a magnet  241 (, 241   a ). As a result, a case  21  of the transmission device  2  is kept rolling while rolling the wheel  1  jointly.  
         [0023]     Please refer to  FIG. 7 , which is a view of an open loop control according to the present invention. As shown in the figure, when the present invention is applied to a vehicle  6 , a control unit  4  can be set which comprises a plurality of switchers  41  with setup values for rotation speed, such as speeds of 300rpm (revolutions per minute), 600 rpm and 1200 rpm, where an open loop control can be formed by the transmission device  2 , an inverter  5  and the control unit  4 . When operating, a user turns on a required switcher  41  to form a loop by the transmission device  2 , the inverter  5  and the switcher  41  so that the transmission device  2  can reach the required rotation speed according to the switcher  41  the user turns on. So, the changes in speed can be achieved.  
         [0024]     Please refer to  FIG. 8 , which is a view of a close loop control according to the present invention. As shown in the figure, except forming an open loop control as shown in  FIG. 7 , a control unit  4  can comprise a tachometer  42  connected with an axle  22  of a transmission device  2 , and a differential amplifier  43  connected to the tachometer  42  and an inverter  5 , so that a close loop control is formed by the transmission device  2 , the inverter  5  and the control unit  4 . When operating, a value for rotation speed is setup in the differential amplifier  43 . As the transmission device  2  is turned on and powered, it is rotated in a speed according to the setup value. According to the rotation speed of the transmission device  2  reported promptly and continuously in the feedbacks of the tachometer  42  to the differential amplifier  43 , the rotation speed error to the setup rotation speed is analyzed. If the error amount is getting smaller, the commutation speed is turned smaller by the inverter  5  so that the rotation speed can reach the set up value. On the contrary, if the error amount is getting bigger, the commutation speed is turned greater by the inverter  5  so that the rotation speed can reach the setup value.  
         [0025]     To sum up, the present invention is an assembly method of use for an electric wheel structure, where a transmission device can be used directly as a hub for a wheel while having a simple structure, a light weight, a small size and a steady transmission.  
         [0026]     The preferred embodiments herein disclosed are not intended to unnecessarily limit the scope of the invention. Therefore, simple modifications or variations belonging to the equivalent of the scope of the claims and the instructions disclosed herein for a patent are all within the scope of the present inventtion.