Abstract
Gear units have been developed to attain the lower running noise and higher durability under higher revolutions and heavier loads in recent years. It is known that the running noise of gears is reduced and the load carrying capacity is improved through having the high precision and the smooth tooth surfaces. The lapping machine designed and manufactured by the authors is able to make the tooth surfaces of hardened gears smooth like a mirror in a short time. The structure and hardness of surface layer of lapped teeth were researched and residual compression stresses at the lapped surface were measured. In addition, the new lapping device was developed to finish tooth surfaces of pinions with small module for gear reducers. The mechanism of the machine and results of lapping tests were stated.
