Redesign of a Differential Housing for a Formula Car (FSAE)

A unique differential assembly was needed for the Lawrence Technological University (LTU) SAE Formula race car. Specifically, a differential was required that had torque sensing capabilities, perfect reliability, high strength, light weight, the ability to withstand inertia and shock loading, a small package, no leaks, the ability to support numerous components. In that regard, an existing differential was selected that had the torque sensing capabilities, but had deficiencies that needed to be fixed. Those deficiencies included the following:

• Differential unit was over 4 kg unmounted, with no housing. This was considered too heavy, when housed properly.
• Bearing surface was provided on only one end of the carrier. This design provides insufficient bearing surface to support either the differential housing or half-shafts
• The internal drive splines integral to the case are not optimized for a perpendicular drive/axle arrangement, such as, a chain drive.
• Differential unit is an open cased frame, lacking in any shields to protect internal gearing.

The differential was re-engineered for the SAE Formula car to address each of the above deficiencies, and helps better achieve an optimized axle that meets all of the race car objectives. To make use of the selected differential, the internal gearing was removed and placed in an all new multipurpose casing. This new casing is the centerpiece for the lightweight final drive assembly. The differential casing and its positioning have been optimized to reduce part count and improve functionality. This design increases reliability and reduces manufacturing time and cost. Design weight of the differential casing is considerably lighter with a dramatically reduced final package size.