Microgeometry optimization of spiral bevel gears

This dissertation aims to give a contribution to the optimization of the microgeometry of spiral bevel and hypoid gears. In particular, it focuses on the open problem of optimizing the tooth contact pattern under load in a systematic way. This main problem is split into two identification subproblems: first, to identify the ease-off topography capable of optimizing the contact pattern, second, to identify the machine-tool setting variations required to obtain such ease-off modifications. Both of them are formulated and solved as unconstrained nonlinear optimization problems. As a by-product of the method proposed, an original procedure to quickly approximate the tooth contact pattern under load is presented. The results obtained are very satisfactory in terms of accuracy, robustness and computational speed. The time required to optimize the contact pattern can be reduced from some days to a few hours. In addition, the systematic nature of the proposed method enables to optimize other contact properties simply by defining an adequate objective function. For instance, the method can be applied to optimize the transmission error function, or to reduce the sensitivity of the gear drive to misalignments.