Studies on 3-D Tooth-Surface Modification of Helical Gears : Changes in Shaft Angle and Tooth-Bearing Pattern Caused by Bending Deformation of Gear Shafts

It is becoming important to modify three-dimensionally the tooth surfaces of gears in consideration of the machining and mounting errors of the gears in the manufacturing process, and of the elastic and thermal deformations of the gear teeth, gear shafts and gear casing during gear running. In this paper, the meshing characteristics of the gears with the shaft angle errors caused by bending of the gear shafts are analyzed. Firstly, two kinds of shaft angle errors are calculated when the structure and loading conditions of the gear set are given. Secondly, the transmission error and tooth bearing pattern of the gears with the shaft angle errors are calculated, which are used to evaluate whether or not the tooth surface modification is appropriate. To confirm the usefulness of this calculation method, tooth bearing tests using ground gears with modified tooth surfaces were conducted. The experimental results agreed with the calculated ones for the most part.