Steering Play Reduction Project
Redesigned the lower steering column, and implemented a lightweight steering column support, reducing free play by more than 90%.
Problem
In our team’s previous design cycle (2024/25), we had excessive free play in our steering system (>7 degrees measured by judges). One of my goals this year was to reduce this free play significantly, by both manufacturing an additional column support, as well as redesigning and remanufacturing the lower steering column.
Prototyping & Initial Testing
The first step in prototyping was to design a “mock” additional support, to see how much an additional support would help in reducing free play, which I decided to test with our previous setup.
As the play was along the lateral axis prior to adding the support, I decided to design the mock support with a high lateral resistance (from the 3/4″ steel tubing), using PA12-CF 3D-Printed pipe-clamp like supports that grab onto the chassis tubes & heat insert-set screws to keep everything held in place.
Result: This additional support did work, and reduced free play by over 50% (longitudinal play from the u-joint still remained). This led our team to proceed with the additional support.
Design & More Testing
The design of the the following support was not done by myself, but due to rules and driver interface constraints, this was the proposed design:
However, I still needed to validate this design, and was worried that a welded support may lock up the steering and/or dramatically increase steering effort, so I decided to manufacture another mock support and support housing.
Ball Bearing Support Housing – Drawing
This testing yielded interesting results – the steering did lock up, and steering effort rocketed in one direction – which I determined after was from the steering column being slightly bent (caused by warping from welding the shaft to the steering rack coupler) – Onto the lower steering column rebuild.
Lower Column Rebuild
As the previous column was warped from welding, adding this support also warranted a full rebuild of the lower column.
Major Changes:
- Reduced the number of components to 2 (hollow splined shaft + steering rack coupler)
- Previous columns used a solid spline + hollow shaft + coupler
- Reduced cost, weight, and manufacturing difficulty in doing so
- Used retaining compound & an aligning press-fit adapter to ensure coaxial relation
- Added a pin as a mechanical backstop (adhesive failure case)
Lower Steering Column – Assembly Drawing
Conclusion
Reduced the free play in the steering wheel by over 90%, all while rebuilding a lighter, simplified, and reduced-cost lower steering column in the process.
