A novel topological modification method for the pinion of the face gears with large contact areas

Face gear assemblies transfer motion between intersecting axes using a cylindrical pinion paired with a face gear. Tooth surface modification is a common way to increase the contact area ratio, reduce maximum contact stress, and improve the reliability of face gear drives. Currently, modification methods focus on individual manufacturing processes for the cylindrical and face gears, without considering their interaction during meshing. This leads to unclear mapping between surface modification and meshing performance, making it hard to control the contact area. To tackle this issue, this paper presents a method for topologically modifying the cylindrical gear tooth surface, taking into account both meshing performance and extensive contact areas. First, the contact lines on both gears’ tooth surfaces are determined. A mathematical model for topological modification is created based on the cylindrical gear’s theoretical tooth surface, focusing on the contact trajectory and direction. The modification amount is applied to the cylindrical gear’s tooth surface to achieve the topologically corrected gear. Finally, a finite element method is used to compare the traditional and proposed modification methods. Results show that the new method increases the contact area ratio by 40% and 50% and reduces the maximum contact stress by 26% and 10%, respectively, compared to the traditional method.