Periodic flank modifications for optimal excitation behavior of practical gear geometries

The design of modern transmissions faces new challenges regarding the main design principles efficiency, service life and noise emissions. These challenges are further intensified by the progressing electrification of vehicle drive systems and the associated trend towards higher rotational speeds. In order to achieve the design objectives at the level of flank modifications, the microgeometry has to satisfy partially competing requirements. Most present gears are designed with combinations of standard modifications to obtain the best possible compromise between the competing goals. The application of periodic modifications provides a possibility to avoid particularly the trade-off between the two design principles load carrying capacity and excitation. The periodic modifications directly compensate the alternating part of the elastic deformations in the mesh without changing the load distribution. They can be used to optimize the excitation behavior independently of the load carrying capacity. Theoretical studies show the potential of periodic modifications to optimize the excitation behavior for a special target load or even for broad load ranges. Experimental investigations at two test rigs of the Gear Research Center (FZG) verify the effectiveness of these flank forms to optimize the excitation behavior for different practical gear main geometries.