Analysis of spur gear forms with tapered tooth profile

This paper presents an analysis of the lateral extrusion of spur gear forms and a comparative evaluation of the methods of lateral extrusion and closed die forging of spur gear forms in terms of mechanical properties of the product. An upper bound solution for lateral extrusion of spur gear forms with tapered tooth profile has been developed. A kinematically admissible velocity field has been proposed. From the proposed velocity field the upper bound solution on relative punch pressure and extrusion load are determined with respect to chosen process parameters. The obtained results are compared with experimental results in order to illustrate the validity of the proposed velocity fields. This indicates that the analysis presented here renders better upper bound solution before corner filling occurs. In addition, gear forms of the same dimension have been produced by both lateral extrusion and closed die forging. The fatigue and hardness tests were applied to gear teeth produced by both processes. The fatigue tests were applied in a manner of three point bending tests. The effect of forming method on the fatigue behavior at the roots of gear teeth and hardness distribution along the radial direction of the tooth are investigated.