Steering Re-Design


Created 12/4/2015

The Shell Eco-marathon has given exciting new challenges to many of our sub-teams, and the Body-Chassis Team is no exception. In particular, Eco-marathon includes requirements for front brakes, a tighter turning radius, and a maximum body height/track-width ratio (track width is the distance between the front wheels). Together, these provided a good opportunity to improve the steering system. Along with the new requirements the team set out to improve the driver’s field of view and vehicle tracking, all while decreasing the weight of the system.

The team gained inspiration from recumbent bicycle steering systems, and performed extensive research on steering geometry. A unique design was synthesized which eliminated the heavy rack and pinion assembly, as well as re-positioned the steering control to the sides of the driver using a carbon steering yoke.

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A prototype axle will be fabricated from aluminum. However, the team is examining the feasibility of fabricating a composite axle of carbon fiber using a pressurized bladder mold. The technique was used successfully last year to produce the intake for the engine, and the axle provides an excellent opportunity to scale up the process.

Another important component is the steering knuckles. Their design considers many factors including the steering axis inclination, castor, ideal Ackerman angle and the space constraints of the car. They also feature removable spindles so the wheel can be removed from the car without dissembling the system or removing the brake calipers. Likewise, the brake calipers are mounted on removable adapters as well to accommodate different size rotors.

Currently the team is finalizing the details of the design, and performing analysis on the components to simulate loads from rough roads, braking and the input from the driver. Next semester, the team will transition to fabrication and integration into the car!