Theoretical investigation and experimental validation of dynamic excitations and vibration characteristics in double-helical planetary gear transmission systems with journal bearings

Journal bearings are essential in improving torque density in the double-helical planetary gear transmission system within a compact volume. However, such a configuration has a particularly pronounced multi-field coupling effect. Considering the impact of journal bearings and the multifield coupling effect, this paper investigates the mesh stiffness of the gear pair, as well as the dynamic characteristics of the gear system. Further, the vibration response of the gear system is assessed based on the finite element (FE) method, and the accuracy of the theoretical analysis is verified by experimental study. The results indicate that, in comparison to the traditional analysis model, the gear system that incorporates the multi-field coupling effect exhibits a significant enhancement in internal dynamic excitations and housing vibration. Furthermore, the influence of the structural parameters of the journal bearing, input loads, and input speeds on the internal dynamic excitations of the gear system and the housing vibration is also examined. Finally, a vibration response test platform for the gear system is constructed, wherein the dynamic excitations and vibration response under a test condition are analyzed and compared.