The strength analysis of a complex planetary gear system for tunnel boring machine reducer

Abstract

          The power train on the reducer of driving cutter head device for a tunnel boring machine makes use of a 3-stages complex planetary gear system. The 3-stages planetary gears are very important parts of the reducer for tunnel boring machine because of the strength problem. The purpose of this study is to calculate the specifications of the 3-stages planetary gears and to analyze the gear bending and compressive stresses of the planetary gears. It is necessary to analyze gear bending and compressive stresses confidently for optimal design of the complex planetary gear system in respect of cost and reliability. In the paper, researchers analyze actual gear bending and compressive stresses of the 3-stages planetary gears using Lewes and Hertz equation and verify the calculated specifications of the complex planetary gear system by evaluating the results with the data of allowable bending and compressive stresses from the Stress - No. of cycles curves of gears. Researchers also analyze PVT factor of gear scoring and evaluate the possibility of scoring failure on the 3-stages planetary gears for the tunnel boring machine reducer.