Quasi-static modeling of long-wave axis deviations in planetary gears for transmission error signal analysis

Abstract Planetary gears are widely used in large transmission applications, such as wind turbines, hydropower plants and industry, due to power density, high gear ratio and efficiency advantages. The advancement of predictive maintenance and gear system design processes is essential to enhance the ratio between durability and used material of gearbox components. Preventing possible downtime due to unforeseen failures in between maintenance intervals also increases resource efficiency. In this paper, a quasi-static FE-based method is presented that calculates the running behavior of planetary gear stages considering time variant and time invariant axis misalignments, tooth flank deviations as well as the influence of coupled meshing areas. A contact algorithm is presented, taking into account load dependent deviations of an adjustable sun gear onto the contact behavior, which is widely used to compensate load-sharing issues. The model can consider these deviations and their influence on the contact behavior hence their characteristic frequency order spectrum. In the future, vibration signatures taking into account manufacturing as well as load dependent deviations can be created to help identifying misalignments in transmission error data. The method can then be used for end of line tests as well as the evaluation of the rest of useful life based on local pressure distributions and tooth root stresses.