Appreciable Improvements in Oil Film Formation and Surface Durability of Gears with Tooth Profile Modification

抄録

The influence of tooth profile modification on the surface durability of spur gears has been studied using mirror-like finished gears with a high accuracy (≒0.1 μm R_max, JIS M 00 class). In order to explain the effectiveness of tooth profile modification, the durations of the elastohydrodynamic lubrication (EHL) condition at the point of contact were measured utilizing an electric resistance method. The results clearly show that the duration of the EHL condition on gear pairs with tooth profile modification have been improved, especially at the beginning and the end points of contact. Even when low hardness gears are used, it is necessary to modify the tooth profile in order to form the lubricating oil film between the meshing teeth and to reduce the surface distress.