Thermal stress effects on the surface durability of gear teeth

Abstract The current standards and design relationships for the surface durability of gears are based on contact stress considerations. Thermal effects are considered only for scoring failures resulting from the destruction of the lubricating film owing to temperature rise. This paper investigates the effect of thermal shock and thermal stress cycling on pitting, micropitting and wear for different gear geometries, materials, operating conditions, machining processes and surface treatments. Because of the current interest in applying surface coating technology to gears, special attention is given to illustrating the potential benefits of this technology in improving the performance and extending the life of gears.