Effect of Coating Materials on Wear in Internal Gears Article in Press

Theoretical and experimental investigation of wear during coupling in internal gears coated with various polymeric coating materials was performed. In the theoretical part of the study, Archard’s wear formulation was adapted to internal gears and wear behaviour in different conditions was determined. Moreover, a fatigue and wear testing apparatus having similar working principle with FZG (Forschungsstelle für Zahnrader und Getreibbau) closed circuit power circulation system was designed and manufactured to experimentally investigate the wear in internal gears. Internal gear-pinion couples manufactured from St50 material were coated with various polymeric materials (PTFE (polytetrafluoroethylene), MoS2 bonded with polyamide, MoS2 bonded with epoxy) in the experimental study. An uncoated internal gear was also investigated to find out the performance of coated gears. Wear values in the teeth profiles of internal gears were determined theoretically and experimentally. Theoretical and experimental studies showed that polymeric coated internal gears have more wear resistance than uncoated ones. It is also observed that coating increases the wear strength of internal gears.