Abstract:
The present application is to power an electric vehicle using this compact method of transmitting rotational energy and movement with three main parts, two of which are identical ( 33 ) ( 34 ). But this type of simple design could have nanotechnology applications.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of PPA Ser. No. 60/792,910 filed Apr. 19, 2006 by the present inventor. 

   FEDERALLY SPONSORED RESEARCH 
   Not Applicable 
   SEQUENCE LISTING OR PROGRAM 
   Not Applicable 
   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   This invention relates to mechanical drive systems, the application described is for an electric vehicle. 
   2. Prior Art 
   Vehicles powered by internal combustion engines move several parts in the engine and driveline before providing power to the wheels. Typically, flywheels, clutch assemblies, transmission shafts, gear clusters, differential gears, and final drive shafts are among these parts. Front wheel drive systems can be more efficient and the addition of automatic transmissions can be less efficient. 
   In all cases power and motion are translated from different rotational planes and sometimes directions before finally being used. Much of the energy required to move these parts and translate this motion is lost. 
   Efficiently Transmitting Vehicle Drive Power: One attempt to improve the efficiency of transmitting vehicle drive power to the wheels is U.S. Pat. No. 6,179,078 B1 Belloso (2001). This ‘Fuel Efficient and Inexpensive Automobile’ has independent internal combustion engines mounted at each rear wheel. In this way power is transmitted separately to each of the rear wheels to drive the vehicle forward through chains, belts and torque converters. The vehicle uses electric motors to power it in reverse. Both engines are used for acceleration. To improve fuel efficiency only one engine is used to maintain a desired speed. 
   This theory of operation seems reasonable. But synchronizing the operation of the separate engine drives would be difficult. An overpowered or underpowered engine or, an engine problem could unintentionally steer the vehicle. The power lost in the torque converters and the drive systems could be significant. High load or long distance rear wheel drive may not be possible. 
   Other improvements for efficiently transmitting vehicle drive power are shown in several electric and hybrid systems. In the following examples electric motors are directly coupled to the drive wheels or, are, part of the drive wheels. U.S. Pat. Nos.: 5,418,437 Couture et al, (1995), 5,921,338 Edmondson (1999), 6,880,654 B2 Plishner (2005), US 2005/0045392 Maslov et al. (2005), US 2006/0180365 Handa et al. (2006). But these designs lead to another problem, suspension arms with a high un-sprung weight. 
   High Un-Sprung Weight Suspension Arms: High un-sprung weight suspension arms are slower to move. Once in motion they are more difficult to control. And they are slower to return to their original position and be ready for additional movement. 
   For example, when potholes are driven over in the roadway the suspension arm(s) and drive wheel(s) are slow to move and find the new bottom. When bumps (small hills) are driven over in the roadway the suspension arm(s) and wheel(s) are slow to return to the roadway if they become airborne. 
   The slow movement of the high un-sprung weight suspension arm makes the drive wheel(s) stay in the air for a longer period of time. When wheels are not contacting the roadway they provide no traction. Vehicles with high un-sprung weight suspension arms hold the road poorly. 
   Objects and Advantages 
   The objects and advantages of the present Patent Application are:
     (a) a simplified drive systems with three main parts;   (b) when the vehicle is moving in a straight line the three moving parts are not moving in relation to one another and create no friction between themselves. These parts rotate together as a single drive axle;   (c) these drive system parts can be located on the chassis reducing the un-sprung weight of the suspension arms;   (d) this drive system is a simple assembly with easy assess for inspection, lubrication or adjustment.   

   SUMMARY 
   The present invention is an efficient way to transmit power by reducing the number of moving parts without creating high un-sprung weight in the suspension arms. 

   
     DRAWINGS 
     Figures 
       FIG. 1  the side view and end view of the drive axle assembly. 
       FIG. 2  a cross sectional side view of the drive axle assembly. 
       FIG. 3  an exploded view of the drive axle assembly. 
       FIG. 4  a side view of the drive axle assembly. 
       FIG. 5  a side view of the drive axle assembly with bearings. 
       FIG. 6  is a cross sectional end view of the drive axle assembly with bearings. 
       FIG. 7  an exploded side view of the drive axle assembly with ball bearings and thrust washers. 
       FIG. 8  a straight on view of the drive sprocket (as if it were against an invisible wall). 
       FIG. 9  the side view of the drive sprocket and hub showing the key for securing the sprocket to an external hollow axle half shaft. 
       FIG. 10  a side view of the drive axle assembly with ball bearings and thrust washers. 
       FIG. 11  drive sprockets installed over the drive axle assembly with ball bearings and thrust washers. 
       FIG. 12  the drive axle assembly with ball bearings and thrust washers connected to electric motors with drive sprockets. A separate chain connects each motor drive sprocket to each axle drive sprocket. This is the complete drive assembly. 
       FIG. 13  a side view of the complete drive assembly. 
       FIG. 14  a cross sectional view of the drive axle assembly with the installation of two roller bearings within each external hollow axle half shaft (four roller bearings total). A single ball bearing is between the external axle half shafts replacing the thrust washers. 
       FIG. 15  a cross sectional end view of the drive axle assembly with roller bearings. 
       FIG. 16  view from above of a two wheel drive vehicle using the drive axle assembly without roller bearings. 
       FIG. 17  the side view of the complete drive assembly. 
       FIG. 18  view from above of a four wheel drive vehicle using the basic drive assembly with roller bearings. 
   

   REFERENCE NUMERALS 
   
       
         31 A side view of the drive axle assembly from any side. 
         31 B side view of the drive axle assembly from any side with thrust washers shown over inner drive shaft between external hollow axle half shafts. 
         31 C cross sectional side view of the drive axle assembly from any side. Ball bearing between axle half shafts replacing thrust washers and roller bearings installed within the external half shaft axles supporting the inner axle. 
         32  end view of the drive system assembly from either end. 
         33  inner axle shaft 
         34  external hollow axle half shafts. 
         35  bearings surrounding each of the external axle half shafts. 
         36  bearing housing with bolt heads shown. In the exploded view these housings are rotated 90 degrees from their assembled position. 
         37  thrust washers 
         38  drive sprocket 
         39  key (within keyway of drive sprocket) 
         40  assembly: drive sprockets keyed to axles 
         41  drive chain 
         42  drive assembly: electric motors connected to axle drive sprockets with chains 
         42 / 31 B assembly: electric motors connected to axle drive sprockets with chains. Inner axle assembly has thrust washers between external axle half shafts and no inner roller bearings. 
         42 / 31 C assembly: electric motors connected to axle drive sprockets with chains. Inner axle assembly has ball bearing between external axle half shafts and roller bearings within external axle half shafts supporting the inner axle. 
         43  ball bearing 
         44  roller bearing 
         45  two wheel drive vehicle 
         46  rotating wheel: arrow represents the drive motion transmitted to the vehicle 
         47  axle shaft connecting drive assembly to wheel 
         48  four wheel drive vehicle 
     
  
   DETAILED DESCRIPTION 
   FIG.  1  thru  11   
   Preferred Embodiment 
   A preferred embodiment of the drive axle assembly for the present invention is described in  FIG. 1 ,  FIG. 2  and  FIG. 3 .  FIG. 3  is an exploded view of the basic drive axle assembly. 
   This assembly consists of 3 main pieces. The inner axle shaft ( 33 ) is surrounded by two external hollow axle half shafts ( 34 ). The external hollow axle half shafts are identical. This complete assembly is a single axle of 3 parts ( 31 A). All these parts are coated with a dry lubricant when assembled. 
     FIG. 4 ,  FIG. 5  and  FIG. 6  show the basic axle assembly ( 31 A) with bearings ( 35 ) and bearing housings ( 36 ). 
     FIG. 7  shows an exploded view of the assembly ( 31 B) with the addition of thrust washers ( 37 ) over the inner axle shaft ( 33 ) and between the two external hollow axle half shafts ( 34 ). This complete drive axle assembly rests within two ball bearing assemblies ( 36 ). These bearings are placed just inside the outside flanges of the external hollow axle half shafts ( 34 ). These flanges (with four bolts holes in each) are where drive axles to the wheels are connected ( 47 ). 
   The drive sprocket shown in  FIG. 8  &amp;  FIG. 9  is keyed to and placed over the drive axle assembly ( 31 B) shown in  FIG. 7 . This complete assembly ( 40 ) is shown in  FIG. 11 . 
   Assembly ( 40 ) is connected to electric motors and drive sprockets with chains ( 41 ) in  FIG. 12 . This is the complete drive assembly ( 42 ). The side view is shown in  FIG. 13 . 
   Operation 
   Preferred Embodiment 
   FIG.  12 , FIG.  16   
   Assembly ( 42 ) using the inner axle assembly ( 31 B) is for an axle drive where both external hollow axle half shafts move in the same direction at the same or similar speeds. This combination is represented by the reference number  42 / 31 B in  FIG. 16 . In this configuration Parts  33  and  34  are moving together and there is little or no movement between them. This would be the most common use of this axle assembly when powering a vehicle ( 45 ).  FIG. 16  shows a rear wheel drive vehicle powered in this manner and ( 46 ) represents the direction the wheels power the vehicle. 
   DESCRIPTION 
   Additional Embodiment 
   FIG.  12 , FIG.  16 . FIG.  18   
   This embodiment is identical to the one described in the previous Preferred Embodiment section with the exchange of Assembly  31 C for Assembly  31 B. This exchange of assemblies is represented by the reference number  42 / 31 C in  FIG. 18 . 
   Operation 
   Additional Embodiment 
   FIG.  12 , FIG.  14   
   The exchange of assemblies  31 B for  31 C allows each of the external hollow half shafts ( 34 ) to rotate in different directions or at much different speeds for prolonged periods of time around the common inner axle shaft ( 33 ). Motors could also be removed from operation and their external hollow half shafts stopped. 
     FIG. 18  shows the use of this axle assembly when powering a vehicle ( 48 ). This type of vehicle with four wheel steering could turn around within the diameter of its own length. In  FIG. 18  Reference Number  46  represents the direction of wheels in this type of turn around. 
   This configuration would also allow the vehicle to move with different orientations of the body. Not necessarily just forward, backward, or turning.