Twin-rotor Coaxial Surface Gear Shunt Drive System Design Method And Vibration Characteristics Study

Structural design of double-rotor coaxial-face gear shunt drive system is carried out to improve dynamic load sharing performance and realize lightweight.Based on the characteristics of closed-loop power flow and virtual restraint configuration design of the system,the teeth matching conditions of the system are established,and the basic parameters of the gears satisfying the load-sharing layout of the system and the synchronous meshing of each branch are calculated.Based on the lumped mass parameter method and combined with the calculation results of gear matching,a 45-degree-of-freedom bending-torsion coupling dynamic model of the system was established considering factors such as manufacturing and installation errors,and the influence of each factor on the dynamic load-sharing performance of the system was analyzed.A multi-objective dynamic load sharing optimization design model with the best dynamic load sharing performance and the lowest system quality as the objective function is established by combining the influence and variation rule of each factor.Through weighted combination method,the global optimum solution of system optimization design is determined,the influence rule of each parameter on optimization objective function is analyzed,and the correctness of the result is verified by genetic algorithm based on Pareto frontier distribution.The results show that the system dynamic load sharing characteristics become worse with the increase of errors and torsional rigidity,especially the influence of each error parameter is more sensitive.The optimization process mainly considers the geometric parameters such as module,number of teeth,pressure angle and tooth width of each gear,which can reflect the degree of influence on the system dynamic load sharing and lightweight.The dynamic load sharing coefficient of the optimized system is reduced by 3.33%and the overall geometric volume of the system is reduced by 16.01%.The actual system has little error tolerance,so the principle of load sharing design is put forward.Based on this principle,considering cost and actual installation and maintenance costs,flexible members are selected as the load sharing design method.The specific configuration of CGi double coupling of cylindrical gear is designed.The load sharing performance of the system with flexible shaft structure is analyzed and it is pointed out that the load sharing coefficient of the system after load sharing design will remain within 0.97-1.03.It also ensures that the load-sharing capacity of the system can be increased by 0.6%under the actual manufacturing and installation requirements compared with the previous one.By using multi-body dynamic simulation technology,the definition of double coupling flexibility is defined in system simulation model.The real dynamic load sharing coefficient B_a=1.030 and the theoretical load sharing coefficient B_{fg FGi}=1.027 are calculated from the meshing force time-domain curve of each gear in the bus stage after simulation.Release the flexibility of the dual coupling of the system,simulate the system before load sharing design,calculate the actual dynamic load sharing coefficient B_b=1.033 by analyzing the engagement force time-domain curve,which is better than the system after load sharing design in practical application.By calculating the theoretical engagement force frequency and observing the frequency domain curves of each gear in the confluence stage of the system,the frequency response of each gear is obtained and the natural frequency of the system is explored.This study provides reasonable design method and feasible analysis means for the design and research of new helicopter power transmission system with compact structure and high reliability.