Influence mechanism of asymmetrical support configuration on dynamic load sharing and distribution of planetary gear

Abstract

Asymmetrical support configuration widely exists in the planetary gear transmissions (PGTs), whose coupling deflection introduces position and misalignment errors under external load, causing uneven load sharing among planets and load distribution skew along the tooth width. This problem becomes increasingly important as PGTs with lightweight structures and large carrying capacity are widely applied, and an efficient model incorporating structure coupling deflections, multi-errors, meshing force, and meshing moment is essential. This article presents such a model combining the instantaneous gear geometry and the finite element method (FEM) to evaluate the influence mechanism of asymmetrical support deflections. The predicted uneven load sharing and distribution characteristics are experimentally verified by measuring the tooth root strain distribution along the tooth width at different gear meshes. These methods have not hitherto been reported in the literature. The result indicates that the attributes of load sharing and load distribution pose contrary requirements on the support stiffness, and decoupling the deflection by improving the support symmetry can reach a near-optimal condition that can both improve the load sharing among planets and alleviate the stress concentration caused by edge contact.