Modeling, Analysis and Testing of Load Distribution for Planetary Gear Trains with 3D Carrier Pinhole Position Errors

A discrete model to study the load distribution behavior of helical planetary gear trains (PGTs) is developed, in which 3D planet position errors, induced by carrier pinhole position errors and tooth modifications, are duly considered. The model adopts a discrete approach with which the planetary gear train is discretized into a series of slice-units in order to ease the problem of gear meshing in 3D cases. In the modelling, compatibility conditions and discrete equilibrium are developed for the coupling among 3D planet position errors, tooth modifications, instantaneous meshing situations, elastic deformations and rigid body spatial motions. Upon the discrete model, a method for analysis of the load distribution is further developed. The influence of 3D planet position errors and tooth modifications on the load distribution was simulated for a helical PGT having three and four planets. Tests on the actual wind turbine PGTs were conducted with results agreed with the simulations obtained, which validate the proposed method.