Numerical approach to forging process of a gear with inner cam profile using FEM

In this paper, numerical approach to cold forging of non-axisymmetric part, sleeve cam, using FEM combined with equivalent area mapping method is presented. The mechanical element dealt with numerical analysis in this paper is a component of automobile starter motor assembly, which is featured gear tooth outside and cam profile inside. Since forging simulation of the whole part is tremendous due to non-axisymmetric cam profile with respect to outer tooth, a finite element model for the tooth analysis based on the equivalent area mapping method, is constructed. The method implies that the actual complicated profile is simply fitted by an arc with appropriate radius, which makes approximated area and original one the same. With the proposed finite element model, forging simulation for symmetric part of the approximated sleeve cam was carried out. Finally, by comparison with experimental results, it is shown that the numerical approach proposed in this study can successfully predict the strain distribution and metal flow of non-axisymmetric forged part.