Engineered Surface Features for Brake Discs to Improve Performance in Fade Conditions 2013-01-2039
Driving on the race track is an especially grueling situation for the automotive brake system. Temperatures can exceed the phase transition temperature of the disc material, wear rates of friction material can be orders of magnitude higher than during street use, and hydraulic pressures and mechanical stresses on components can approach their design limits. It is a given that friction material under these conditions will wear unevenly - causing taper and cupping wear - and an associated set of performance degradations will occur, including an increase in fluid consumption (pedal travel increase) and loss of mechanical efficiency (pedal force increase). Some high performance vehicles use surface features on brake discs, such as crossdrilling or slotting, to improve apparent friction levels in aggressive use (as well as to add marketing appeal), and generally accept a significant degradation in lining wear characteristics (both in overall wear rates and in the exacerbation of uneven wear behaviors) in order to achieve this. This paper proposes a method of using the elevated wear rates caused by brake disc surface features to partially correct the uneven wear characteristics inherent in the brake corner design. This in turn results in improved fade and fluid consumption characteristics during aggressive usage, even relative to a baseline disc without surface features.