Design And Load Sharing Analysis Of Twice Split-Torque Transmission System With Face Gears And Cylindrical Gears

Cylindrical gear and face gear split-torque transmission system have wide application prospect in the aviation field with considerable advantages.It is a key technology to ensure the load of each branch of the system equal.This paper conducts research on twice split-torque transmission system with face gears and cylindrical gears,including optimization and tooth matching,research on static and dynamic load-sharing characteristics.Firstly,an optimization model with objective of minimum quality is established and solved by SQP.Thus optimal values of design parameters of system are obtained.Based on optimization results,tooth matching conditions are introduced,and feasible tooth matching schemes are proposed.Results show that influence of tooth matching results on total volume and load sharing performance should be taken into account when selecting tooth matching schemes.Secondly,statics model of the system is established,and static equilibrium equations of the system are deduced and solved.Thus,load-sharing coefficients of each branch of the system are obtained.Influences of torsional stiffness,supporting stiffness and general transmission errors on static load-sharing characteristic are analyzed.Results show that torsional stiffness of spilt-torque shafts and support stiffness of input shaft have a great influence on load sharing performance of input stage,that torsional stiffness of double gear shafts and general transmission errors have significant influence on load sharing performance of the system.Thirdly,considering time-varying meshing stiffness,torsional stiffness,supporting stiffness,eccentricity errors and backlash,bending-torsional coupled dynamic model of the system is developed based on theory of lumped parameter method.With characteristic of closed loop structure,rigid body displacements of the dynamic equations are eliminated,and non-dimensional equations is obtained.Through solving the dynamic equations using Runge-Kutta method,dynamic load-sharing coefficients are acquired.Influence of backlash,eccentricity errors,torsional stiffness and supporting stiffness on dynamic load-sharing characteristics were analyzed.Results show that radial fluctuation of input shaft can effectively improve dynamic load sharing performance of input stage,that increasing backlash,reducing eccentricity errors or rationally configuring the torsional stiffness of transmission shafts can improve dynamic load sharing performance of system.