INFLUENCE OF GEAR TOOTH GEOMETRY ON TOOTH STRESS OF EXTERNAL AND INTERNAL GEARS

Type and geometry of the cutter influence the generated fillet in a gear tooth. Thus optimization of the cutter dimensions is an important step in minimizing gear stress. Gear tooth geometry of external and internal involute gears can be described by the same equations, if we apply the following rule: The number of teeth is positive in external gears and negative in internal gears; the rack has an infinite number of teeth. We demonstrate that both gear geometry and tooth stress, i.e., the location of maximum tangential stress, the amount of tooth stress and the stress concentration factor, change continuously from external to internal gears. The results obtained by FEM computations are verified by photoelastic experiments. Data for calculation of gears, especially internal gears, are presented and discussed.