Drivetrain & Gearbox
Previous gears and gearbox were reviewed to set the new design goals. The previous gearbox had severe uneven pitting on input shaft teeth and plays in the output shaft. The new gearbox had to take additional axial loadings from the half shafts. To resolve the issues from the previous design, the bearing distance was widened and face width was increased for all the gears. Load analysis was redone and new sets of lighter bearings were reselected. The output shaft bearings were reselected as angular contact roller bearings. To ensure there was no axial play in the output shaft, custom spacers were designed to lightly preload the angular contact roller bearings.
The gearbox shells was redesigned to fit the new bearings and oil seals. The support structures was designed to ensure the gearbox shells become a cohesive part of the rear suspension. To ensure the gears are properly lubricated, all the supports were designed to locate on the outside of the gearbox. The gearbox shells are smooth inside so that oil can easily transfer from the bottom to the top. The gearbox was relocated to in the frame to shorten the wheelbase, as it was driven by a custom tuned CVT.
The gearbox shells were machined on VF3 from two blocks of 6061 aluminum. The shafts and gear blanks were manually turned on lathe. The 4340 steel gear blanks were surface grinded to the specific face width and the spokes were CNC machined. The team sponsors helped us to cut the gear teeth. After all the components were machined, two gearboxes were assembled. They were break-in on the lathe and installed to the car for additional testing for competitions.