After some last minute revisions of our motor and gearbox choices, we were able to move towards finalizing some aspects of the drive system. The main change is the drive housing is now a 1/16″ wall 2024 tube with welded flanges at either end. Additionally, the shaft support is now provided by a ball bearing rather than a solid bushing. The system still has a lip seal to protect the bearings and now also incorporates an additional weldment to support the weathertight Amphenol connector we will be using to make the necessary electrical connections. The entire drive system, including the wheel, currently weighs about 7 pounds per corner.
In addition to the weathertight motor housing, we have also been investigating many different types and options for wheels, including built-up wheels, billet wheels (machined from solid), spoked wheels, and wheels made from commercial components. We believe we have found a potentially very good wheel in components made for high-performance motorsports. We are looking into using the inner section of a 3-piece 13″ racing wheel used on many smaller race cars such as Formula SAE vehicles. After removing the bead and smoothing out the shape, we would glue ribbed neoprene belting to the outside to form a cleated tread surface. Typically, a 3-piece aluminum race wheel is bolted to a forged aluminum hub which bolts to the axle. In our case, we would use a .050″ titanium sheet to connect the wheel to our drive hub. The main advantage to using a prefabricated race wheel is that these wheels are spun from a single sheet rather than machined from billet (time-consuming and expensive) or formed from several components (not particularly strong). The spinning process strengthens the material and provides an excellent starting shape for further machining operations.