FSAE Steering System

Designing the structure of the steering system is a challenging problem because it has to constrain u joints in a stiff, but servicable fasion. The location of the steering wheel is determined by the ergonomics of the driver, the rack location is determined by the vehicle dynamics of the steering system, and the overall width of the column is constrained by whats called the driver template. So packaging the entire system gets pretty tricky.

Solution

Our U joint choice simply came down to what we already had in the shop. At the time I wasnt able to find U joints compact enough to justify the cost. For the bearings, I specced needle pin roller bearings due to their thin profile, high load rating, and light weight. I fitted them over cut down splines and a sleeve that tied them together and acted as an inner bearing race. The sheet metal column suports were bent out of 14 gauge steel and integrated with the dashboard to stiffen up both structures. Almost every part I designed for this system served multiple purposes, allowing the package to fit efficiently into the provided space and minimize mass. This system is about 20% lighter than the previous years and easily dissassemblable with just 4 bolts. Service time dropped from 25 minutes, to just 5 for a tear down and rebuild. 

What I should have done differently

• Needle pin roller bearings seemed great for this application, however they could not be preloaded so they introduced a small amount of slop to the system. Greased bushings might have been a better solution for this. 

• Angling the steering wheel further forward might have allowed us to make the steering wheel bigger and run one u joint instead of two. This would have helped with compliance and mass, however we would have had to run either progressive or digressive steering.