This paper presents a gear design optimization approach that was applied to reduce both tooth contact
temperature and noise excitation of a high-speed spur gear pair running without lubricant. The optimum gear
design search was done using the RMC (Run Many Cases) program from The Ohio State University. Over
480 thousand possible gear designs were considered, which were narrowed down to the 31 best candidates
based on low contact temperature and low transmission error. The best gear design was selected
considering, also, its manufacturability. The selected optimum gear design was compared to an existing gear
set using LDP (L oad Distribution Program) from The Ohio State University. Tooth contact temperature was
calculated for both designs using dry a steel-on-steel coefficient of friction. Predicted contact temperature
correlated well with results observed on dynamometer tests with the existing gear set. Predictions with the
optimized design showed a 48% contact temperature reduction and a 79% noise excitation reduction. The
low contact temperature of the optimized design will significantly contribute to preventing tooth surface
damage under no lubricant operating conditions.