Study on the optimum standard parameters of hob optimization for reducing gear tooth root stress

Abstract Optimising the hob used to manufacture gears is an attractive approach for minimizing the gear tooth root stress. However, currently available approaches often require modifying the hob for every gear case, which limits their practical application and increases design and manufacturing costs. In this study, two sets of Bezier curve parameters for gear hobs were developed to minimize the tooth root stress: one for standard hobs and the other for protuberance hobs. The two parameter sets can be used to modify any hob and effectively reduce the gear bending stress, and they are widely applicable to all common gear cases. Calculation with the finite element method indicated that the first-best parameter set for standard hobs reduced the stress of most gear cases by 6%–10%. The second-best parameter set for protuberance hobs reduced the stress of almost all gear cases by 7%–15%. The average optimisation potential was 10.73%. Meanwhile, the manufacturing cost is very low because an optimised hob can be applied to producing other gears. These two parameter sets are a significant contribution to the optimisation and manufacture of gears.