The spur planetary gear torsional stiffness and its crack sensitivity under quasi-static conditions

Abstract

The sun-planet and ring-planet tooth mesh stiffness variations and the resulting transmission errors are the main internal vibration generation mechanisms for planetary gear systems. This paper presents the results of torsional stiffness analysis of involute spur planetary gear systems in mesh using finite element methods. A planetary gear model with three planet gears and fixed ring gear and its subsystem models have been developed to study the subsystem and overall torsional stiffnesses. Based on the analysis of torsional mesh stiffness, predictive models for single branch sun-planet-ring and overall planetary gear torsional stiffnesses have been proposed. A crack coefficient was introduced to the sun-planet and ring-planet meshes to predict the effect and sensitivity of changes to the overall torsional mesh stiffness. The resulting mesh stiffness crack sensitivity of the overall gear system was analysed under quasi-static conditions. It was found that the carrier arm stiffness has great influence on the crack sensitivity while the overall stiffness was most sensitive to the crack on the sun-planet mesh.

The diagnostic analysis of the fault coupling effects in planet bearing

“…The tooth mesh stiffness variation of a sun-planet gear pair and the ring-planet gear pair were modelled from the isolated sun-planet FE model and the isolated sun-planet FE model respectively. The detailed steps on how to model the gear finite element model and how to calculate the mesh stiffness using the established models can be found in the previous works [32]. The value of the bearing stiffness can be estimated based on the Hertzian contact theory [33].…”

Vibration response from the planetary gear with flexible ring gear

“…For a planetary gear set, the main internal excitations come from the variation of the sun-planet mesh stiffness and the variation of the ring-planet mesh stiffness. The developed process on how to calculate these stiffnesses can be found in Xue et al (2016) and special care has been given to the effect of the boundary condition on the ring-planet mesh stiffness, which can be found in Xue and Howard (2015). Figure 2 shows the FEA models for the ring gear with uniform supports and 11 pin supports that were used for mesh stiffness estimation.…”

Noise Prediction of Traction Gear in High-Speed Electric Multiple Unit

“…By means of computer-aided modelling and finite element simulation analysis, domestic and foreign scholars have conducted extensive research on the dynamic mechanical characteristics of gear transmission. Xue et al [1] established the spur planetary gear model by using the parametric method, simulated and analysed the gear meshing process, and obtained the contact pressure and stress in a meshing period. Kim et al [2] proposed a new dynamic model of the planetary gear, where the pressure angles and contact ratios change with time.…”