Analysis And Optimization Of The Vibration And Noise Of A Double Planetary Gear Power Coupling System

The power coupling system is one of the main sources of vibration and noise of the hybrid electric vehicle.The research and improvement of the vibration and noise characteristics of the power coupling system is of great practical significance to the improvement of ride comfort and the expansion of market share of hybrid electric vehicles.In this paper,the double planetary gear power coupling system of a kind of hybrid electric vehicle is used as the research object,and the vibration and noise characteristics of the power coupling system under the non-steady condition are investigated,and the specific optimization and improvement measures are put forward for the vibration and noise.The main work of the paper is as follows:Firstly,based on the multi-body dynamics theory and finite element method,the dynamic model with rigid and flexible bodies of the power coupling system is established with software UG,ADAMS and ANSYS,and the multi-body dynamic simulation under the transition condition is carried out.The time-domain and frequency-domain characteristics of the gear meshing force and bearing constraining force of the power coupling system under simulation conditions are obtained and analyzed in detail.Then,the solid model and the finite element model of the housing of the power coupling system are established by using software UG and ANSYS,and the constrained modal analysis and vibration displacement response analysis of the housing are carried out.Then,based on the acoustic boundary element method,the boundary element model of the outer housing of the power coupling system is established with software LMS.Virtual.Lab.The radiated noise of the housing is simulated and analyzed.The frequency spectrum of the housing acoustic power level and the sound pressure level of the housing surface at each peak frequency of the housing acoustic power level are obtained respectively.Next,the number of teeth,modulus,pressure angle,helix angle,displacement coefficient and other macro-geometric parameters of the planetary gear of the power coupling system are optimized with software KISSsoft.After optimization,the strength of gears is improved and the difference of the contact stiffness of each gear pair decreases to some extent,which indicates that the vibration and noise of the gears from the front and rear planet rows have been improved.Then,by using software ADAMS,the dynamic characteristics simulation results of the power coupling system after gear macro-parameter optimization are compared with those before optimization and it is verified that the optimization of macro-parameters of planetary gear is effective to reduce the vibration and noise of the power coupling system.Finally,the solid assembly model of the power coupling system is established by using software Romax Designer,and the micro-parameters of the sun gear,planetary gear and internal gear from the front and rear planet rows of the power coupling mechanism are optimized,which is called gear shape modification.After modification,the gear transmission error,gear meshing impact and gear bias load of the power coupling mechanism are improved,and the vibration and noise characteristics of the power coupling system are optimized.