Abstract:
A motor main shaft and auxiliary shaft coaxial drive system to provide dual transmission input or output at single end or both ends by having its main shaft made in hollow to receive insertion of an auxiliary shaft coaxially; with separate transmission to link to respective load; the auxiliary shaft may be driven by other dynamic source; a controllable clutch being provided between the main shaft and the auxiliary shaft of the motor; the auxiliary shaft being coupled to the main shaft of the motor either to be driven by the motor main shaft or to drive the motor main shaft; or the motor main shaft to be disengaged from the auxiliary shaft by manipulating the clutch.

Description:
BACKGROUND OF THE INVENTION 
   (a) Field of the Invention 
   The present invention is related to a motor main shaft and auxiliary shaft coaxial drive system, and more particularly, to a compact coaxial dual drive system in a single motor by having axially inserted the auxiliary shaft into the main shaft of the motor and both shafts are respectively provided with transmission at different speed ratios for output or input. 
   (b) Description of the Prior Art 
   In a conventional dual shaft drive system, usually two motors are coaxially provided by having their independent main shaft coaxially connected in series and separately driven, or having a main shaft of a single motor provided separately from the revolving shaft driven by another dynamic drive. Taking the passive bike generally available in the market that is subject to the manual drive or motor drive or simultaneous drive by both for example, both of an auxiliary shaft of the manual drive and a main shaft of a motor are usually separately located in the absence of an coaxial structure. Therefore it has the flaws of consuming more space and being a more complicated structure; and the same flaws are observed with other applications operating on dynamic and manual mixed drive, e.g., moped, light weight wheeled vehicle or any other carrier or mechanical load. 
   SUMMARY OF THE INVENTION 
   The primary purpose of the present invention is to provide a motor main shaft and auxiliary shaft coaxial drive system. The system provides dual transmission input or output at single end or both ends by having its main shaft made in hollow to receive insertion of an auxiliary shaft coaxially adapted with separate transmission to link to respective load. The auxiliary shaft may be driven by other dynamic source, and a controllable clutch being provided between the main shaft and the auxiliary shaft of the motor. The auxiliary shaft is coupled to the main shaft of the motor either to be driven by the motor main shaft or to drive the motor main shaft; or the motor main shaft is disengaged from the auxiliary shaft by manipulating the clutch. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view showing a basic structure of a motor unit of the present invention with motor stator provided externally and motor rotor provided internally. 
       FIG. 2  is a side view of  FIG. 1 . 
       FIG. 3  is a schematic view of a structure of a preferred embodiment of the present invention to jointly drive a load by a motor main shaft and an auxiliary shaft coaxially inserted into the motor main shaft. 
       FIG. 4  is a side view of  FIG. 3 . 
       FIG. 5  is a schematic view showing a basic structure of a motor unit of the present invention with motor rotor provided externally and motor stator provided internally. 
       FIG. 6  is a side view of  FIG. 5 . 
       FIG. 7  is a schematic view of a structure of another preferred embodiment of the present invention to jointly drive a load by a motor main shaft and an auxiliary shaft coaxially inserted into the motor main shaft taken from  FIG. 5 . 
       FIG. 8  is a side view of  FIG. 7 . 
       FIG. 9  is a schematic view showing another preferred embodiment yet of the present invention having provided a controllable clutch at where between the hollow motor main shaft and the auxiliary shaft coaxially inserted into the motor main shaft. 
       FIG. 10  is a side view of  FIG. 9 . 
       FIG. 11  is a schematic view showing another preferred embodiment yet of the present invention with two units of power trains respectively provided with a one-way transmission. 
       FIG. 12  is a schematic view showing another preferred embodiment yet of the present invention having its power chain driven by the main shaft of the motor of the present invention provided with a one-way transmission, and the power chain driven by the auxiliary to directly drive the rotation part of the load. 
       FIG. 13  is a schematic view showing another preferred embodiment yet of the present invention having a one-way transmission provided to the power train driven by the auxiliary shaft and the power chain driven by the motor main shaft to directly drive the rotation part of the load. 
       FIG. 14  is a schematic view showing another preferred embodiment yet of the present invention having a one-way transmission in sequence of a first power train, a second power train and a rotation part of a load. 
       FIG. 15  is a schematic view showing another preferred embodiment yet of the present invention having a one-way transmission in sequence of the second power train, the first power train and the rotation part of the load. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In a conventional dual shaft drive, such as that applied in a carrier of two or more than two wheels driven manually and by motor, the manually driven auxiliary shaft and the motor main shaft are usually separately provided at different places instead of being co-axially provided; they therefore consume comparatively a larger amount of space. The co-axially provided motor main shaft and the auxiliary shaft are specially designed to correct the defects of consuming too much space by inserting the auxiliary shaft into the motor main shaft, with each respectively being provided with a transmission, such as a dual chain gear structure to drive a load, so to save space and reduce the structural complexity. Meanwhile, the auxiliary shaft may be driven manually or by another dynamic source, or alternatively, a controllable clutch may be provided to manipulate the coupling of the auxiliary shaft to the motor main shaft for the transmission or to disengage from the motor main shaft. 
   As illustrated in  FIG. 1  for a schematic view of a basic structure of the present invention, wherein, a motor unit is comprised of a motor stator provide externally and a motor rotor provided internally.  FIG. 2  is a side view of  FIG. 1 . The present invention is essentially comprised of a motor unit  100  provided with a hollow motor main shaft  101 , and an auxiliary shaft  102  co-axially inserted into the hollow motor main shaft  101 . The motor unit  100  is provided externally with a motor stator  103  and internally with a motor rotor  104 . The motor rotor  104  freely revolves inside the motor stator  103  and is provided with the hollow motor main shaft  101  to coaxially receive the insertion of the auxiliary shaft  102 , which in turn freely revolves inside the motor main shaft  101 , and a proper bearing structure is each provided among revolving structures in the motor unit  100 . 
     FIG. 3  is a schematic view of a structure of a preferred embodiment of the present invention to jointly drive a load by a motor main shaft and an auxiliary shaft coaxially inserted into the motor main shaft; and  FIG. 4  is a side view of  FIG. 3 . Wherein, the hollow motor main shaft  101  and the auxiliary shaft  102  in the motor unit  100  illustrated in  FIG. 1  is respectively adapted with a transmission at different speed ratios to drive a common load. That is, two transmission units at different speed ratios are respectively adapted to where between the load rotation part  201  and the motor main shaft  101 , and the load rotation part  201  and the auxiliary shaft to jointly drive the load rotation part  201  that revolves in a bearing structure  202 . Wherein, a first transmission  211  is provided for the motor main shaft  101  to drive the load rotation part  201  thus to form the first power train while the second transmission  212  is provided for the auxiliary shaft  102  to drive the load rotation part  201  thus to form a second power train. Meanwhile, two one-way transmission units  221 ,  222  are respectively provided between the load rotation part  201  and the first transmission  211  and the second transmission  212  depending on the transmission functional desired, so to transmit the revolving power from the motor train shaft  101  or the auxiliary shaft  102  to the load rotation part  201 , which is prevented from engaging the inverse transmission to the motor main shaft  101  or the auxiliary shaft  102  on the prime mover side. 
   Furthermore, if two-way transmission is required between each transmission and the load rotation part  201 , a linkage for direct transmission may be selected; or a one-way transmission is provided between the load rotation part  201  and the transmission  211  or  212  as applicable while the other transmission  211  or  212  is selected for direct transmission linkage. 
   If structural requires, the coaxial drive system of the motor main shaft and the auxiliary shaft may be comprised of a motor unit having the motor rotor provided externally and the motor stator provided internally as illustrated in  FIG. 5  for a schematic view showing a basic structure of a motor unit of the present invention with motor rotor provided externally and motor stator provided internally; and  FIG. 6  for a side view of  FIG. 5 . Wherein, an internal motor stator  303  provided with a through hole of the motor unit  300  is unilaterally fixed with the through hole in the internal motor stator  303  to receive the insertion of an auxiliary shaft  302  while an external motor rotor  304  freely revolves around the internal motor stator  303  and the auxiliary shaft  302 , and the motor main shaft  301  having a hollow structure is driven by the external motor rotor  304 . 
     FIG. 7  is a schematic view of a structure of another preferred embodiment of the present invention to jointly drive a load by a motor main shaft and an auxiliary shaft coaxially inserted into the motor main shaft taken from  FIG. 5 , and  FIG. 8  is a side view of  FIG. 7 . Wherein, the first transmission  211  is provided between the load rotation part  201  and the motor main shaft  301  having a hollow structure driven by the external motor rotor  304  of the motor unit  300 ; while the second transmission  212  is provided between the load rotation part  201  and the auxiliary shaft  302  coaxially penetrating the through hole of the internal motor stator  303 . 
   Furthermore, the coaxial drive system of the motor main shaft and the auxiliary shaft may be adapted with a controllable clutch at where between the motor main shaft and the auxiliary shaft as illustrated in  FIG. 9  for a schematic view showing another preferred embodiment yet of the present invention having provided a controllable clutch at where between the hollow motor main shaft and the auxiliary shaft coaxially inserted into the motor main shaft, and in  FIG. 10 , a side view of  FIG. 9 . The preferred embodiment illustrated in  FIGS. 9 and 10  takes the motor unit  100  provided with an external motor stator and an internal motor rotor as shown in  FIG. 1  while a controllable clutch  500  is provided between the motor main shaft  101  and the auxiliary shaft  102 . The first transmission  211  and the second transmission  212  operate at different speed ratios. To avoid interference of the operation by both transmission units  211 ,  212  at different speed ratios, a one-way transmission to prevent interference is each provided at where between the load rotation part  201  and the first transmission  211  provided in relation to the motor main shaft  101  serving as the prime mover side, and at where between the load rotation part  201  and the second transmission  212  provided in relation to the auxiliary shaft  102 . Accordingly, when the controllable clutch  500  is disengaged, the revolving power from the motor unit  100  drives from the motor main shaft  101  the load rotation part  201  through the first transmission  211 ; or when the controllable clutch  500  is in closed status, the motor unit  100  simultaneously drives the motor main shaft  101  and the auxiliary shaft  102 , and then drives the load rotation part  201  respectively through the separately adapted first transmission  211  and second transmission  212  operating at different speed ratios and the interference resulted from different speed ratios is eliminated by the one-way transmission provided at where between the first transmission  211  or the second transmission  212  adapted in relation to the motor main shaft  101  and the auxiliary shaft  102 , and the load rotation part  201 . 
   The structure of the controllable clutch  500  provided between the motor main shaft and the auxiliary shaft may be also applied in the motor unit  300  having an external motor rotor and an internal motor stator as illustrated in  FIG. 5  with the structural principles for the controllable clutch  500 , the first transmission  211 , the second transmission  212  and the load rotation part  201  same as that of the preferred embodiment illustrated in  FIGS. 9 and 10 . 
   If an eccentric type of clutch is used for the controllable clutch  500  of the coaxial drive system of the aforesaid motor main shaft and the auxiliary shaft, an eccentric clutch that is closed in normal condition and is disengaged when the speed increases up to a preset value, or another eccentric clutch that is disengaged in normal condition and is closed when the speed increases up to a preset value depending on the function required. Meanwhile, the relation between the speed ratios of the first transmission  211  and the second transmission  212  and the layout of the one-way transmission may be relatively adapted according to the transmission mechanism. 
   The additional one-way transmission in the power train to eliminate interference due to different ratios during the operation of the first power train and the second power train comprised of two transmission units  211  and  212  operating at different speed ratios and the load rotation part  201  in those preferred embodiments illustrated in  FIGS. 1 through 10  may be provided in the following methods:
     (1) As illustrated in  FIG. 11  for a schematic view showing another preferred embodiment yet of the present invention with two units of power trains respectively provided with a one-way transmission, two one-way transmission units  221 ,  222  are respectively provided at an interference point in the related power transmission operation for two power trains to avoid interference, the first power train is formed between the input side of the first transmission  211  driving by the motor main shaft  101  or  301  and the output side of the first transmission  211 , and the load rotation part  201 ; and the second power train is formed between the input side of the second transmission  212  driving by the auxiliary shaft  102  and the output side of the second transmission  212 , and the load rotation part  201 .   (2) As illustrated in  FIG. 12  for a schematic view showing another preferred embodiment yet of the present invention having its power chain driven by the main shaft of the motor of the present invention provided with a one-way transmission, and the power chain driven by the auxiliary to directly drive the rotation part of the load, the first power train is formed between the first transmission  211  driven by the motor main shaft  101  or  301  and the load rotation part  201  and is provided with the first one-way transmission  221 ; while the second power train is formed by having the second transmission  212  driven by the auxiliary shaft  102  to directly drive the load rotation part  201 .   (3) As illustrated in  FIG. 13  for a schematic view showing another preferred embodiment yet of the present invention having a one-way transmission provided to the power train driven by the auxiliary shaft and the power chain driven by the motor main shaft to directly drive the rotation part of the load, the second power train is formed between the second transmission  212  driven by the auxiliary shaft  102  or  302  and the load rotation part  201  provided with the second one-way transmission  222 ; while the first power train is formed by having the first transmission  211  driven by the motor main shaft  101  to directly drive the load rotation part  201 .   (4) As illustrated in  FIG. 14  for a schematic view showing another preferred embodiment yet of the present invention having a one-way transmission in sequence of a first power train, a second power train and a rotation part of a load, the output side of the second transmission  212  driven by the auxiliary shaft  102  is driven first through the first one-way transmission  221  by the output side of the first transmission  211  driven by the motor main shaft  101  or  301 ; and the load rotation part  201  is driven through the second one-way transmission  222  by the output side of the second transmission  212  driven by the auxiliary shaft  102  for the first power train to drive the second power train in one direction, in turn the second power train drives the load rotation part  201  in the same direction, resulting in a one-way transmission mechanism comprised of the first power train, the second power train and the load rotation part in sequence.   (5) As illustrated in  FIG. 15  for a schematic view showing another preferred embodiment yet of the present invention having a one-way transmission in sequence of the second power train, the first power train and the rotation part of the load, the output side of the first transmission  211  driven by the motor main shaft  101  is driven first through the second one-way transmission  222  by the output side of the second transmission  212  driven by the auxiliary shaft  102  or  302 ; and the load rotation part  201  is driven through the first one-way transmission  221  by the output side of the first transmission  211  driven by the motor main shaft  101  for the second power train to drive the first power train in one direction, in turn the first power train drives the load rotation part  201  in the same direction, resulting in a one-way transmission mechanism comprised of the second power train, the first power train and the load rotation part in sequence.   

   To sum up, the coaxial drive system comprised of the motor main shaft and the auxiliary shaft of the present invention by having the motor main shaft made in a hollow structure to receive co-axially the insertion of the auxiliary shaft in adaptation of the one-way transmission provided at the load rotation part is compact and reduce the complexity of a specific drive, and an optional clutch is provided between the motor main shaft and the coaxially inserted auxiliary shaft as required is innovative and providing specific function. Therefore, this application for patent is duly filed accordingly.