Analysis Of Load Sharing Characteristics Of 2 Input Helicopter Main Reducer Split-torque Transmission System

2-input gear split-torque transmission system with the power split to meet the requirements of high speed and heavy load in the case of less quality of the spare parts. This transmission has a wide application prospect in the main reducer of medium and heavy helicopters with a lot of properties such as higher reliability, lower noise and lower energy loss. However, because of the structural characteristics of the 2-input gear split-torque transmission system, the system can not meet the requirements of the use. Based on the above, study on the dynamics and load characteristics of the 2-input gear split-torque transmission system has great significance. This paper mainly works in four aspects: analysis of static load-sharing characterisitics of 2-input gear split-torque transmission system, establishment of dynamics model, influence of tooth surface friction on the dynamic characteristics and analysis of dynamics load-sharing characterisitics.A static model was established for the transmission system which was in the case of elastic deformation. With the characteristic of closed loop structure, the deformation coordination condition of the system was deduced and the static equation was obtained. Then, the impact of torsional rigidity of dual gear shaft, installation angle between two inputs and gear installation error on static load-sharing characteris of system was analyzed.Calculation model of friction coefficient based on EHL theory was obtained. According to the meshing characteristic of spur gear and herringbone gear, dynamic excitation of friction force and friction torque coefficient was analyzed. Based on this, a dynamic model with the consideration of the time-varying friction coefficient, the time-varying mesh stiffness, the reversing bevel gear drive and the lateral displacement of transmission shaft was established. The dynamic differential equations of the whole drive system were derived.The dynamic response of different tooth surface roughness were acquired through solving of the dynamic equations by the fourier series method. The impact of tooth surface roughness on the dynamic meshing force, the dynamic transmission error and the dynamis bearing force were analyzed.With the dynamic meshing forece of each branch, the dynamic load-sharing characteris were obtained. Then, the impact of torsional rigidity of shaft, support stiffness and gear eccentri error on dynamic load-sharing characteris of system was analyzed. Based on the sensitivity analysis of the average load factor, the influence of structural failure on dynamic load-sharing characteris was analyzed.