Research on Increasing Hob Tip Fillet Radius to Decrease Addendum Modification Coefficient

Abstract

Reasonable design of hob tip fillet and calculation of modification coefficients were researched to avoid undercutting in this paper. The undercut gears were generated in the virtual environment based on Pro / E software. Meanwhile, parametric finite element models of undercut gear, ordinary modified gear generated by standard hob and modified gear generated by hob with tip fillet radius increased,were founded by APDL (ANSYS Parametric Design Language).The results show that the minimum modification coefficients chosen to avoid undercutting by traditional modification method may not meet the requirements of contact ratio or addendum thickness.While through reasonable design of hob tip fillet, modification coefficients calculated not only avoid undercutting to improve the tooth bending strength but also meet the requirements of contact ratio ε>1.2 and addendum thickness δ>0.25m (module) .