Improvements in the micro tooth surface topography of hobbed spur and helical gears

Abstract

A new model of the gear hobbing process is presented in this paper to determine the micro tooth surface topography in spur and helical gears. The model is based on the generation of tooth surfaces by successive cuts of the finite number of hob teeth, as they come into interaction with the gear tooth. For every relative position of the hob and the gear, an analysis is carried out to find the active cutting edge points which generate the gear tooth surface. Repeating this procedure for all the selected gear tooth surface points, the micro topography of the gear tooth surface is determined. Therefore, the developed method determines the deviations of the manufactured tooth surface from the theoretical tooth surface of spur and helical gears. The method is applied to improve the micro tooth surface topography of spur and helical gears, namely to reduce the deviations of the hobbed tooth surface. Spur and helical gear examples are used to demonstrate the effectiveness of the method.