Research Of Model And Characteristic Of Vibration Noise Of The Hybrid Transmission

At present,the research on NVH(Noise,Vibration,Harshness)performance of dual planetary hybrid electromechanical coupling transmission is relatively few at home,which limits popularization and development of hybrid technology in China.Compared with traditional transmission,hybrid transmission in structure and layout has undergone significant changes,and corresponding NVH performance has also undergone a significant change.Therefore,improving vibration and noise characteristics of hybrid transmission must be paid attention to the process of research and development.Taking dual planetary hybrid system as the research object,this paper designs and analyzes the structure of electromechanical coupling transmission.In order to improve vibration and noise performance of transmission,CAE joint simulation method is used to study vibration noise problem through three-dimensional modeling software,dynamic analysis software,finite element analysis software,acoustic analysis and professional gear optimization software,which can provide the basis for early development and post-optimization of transmission assembly and a new research idea to solve the NVH problem of the hybrid system.Firstly,the structure of hybrid transmission assembly is designed and analyzed,especially structural parameters and meshing parameters of gears of planetary gears in power coupling mechanism.The solid model is carried out by Pro/E software and virtual assembly is established without interference.Secondly,multi-body dynamics model of double-planetary array power coupling mechanism is established with ADAMS software.According to the selected vehicle limit condition,kinetic simulation and dynamic simulation of power coupling mechanism are carried out.The simulation results are compared with the theoretical values to verify the validity of the model.At the same time,the dynamic excitation of the power coupling mechanism in the transmission bearing housing is calculated to provide load excitation for the vibration characteristics analysis of the transmission box.Beside,The finite element model of transmission box is established with Hypermesh software.Modal simulation is carried out with Ansys software as analysisplatform to obtain the inherent characteristics of transmission box structure.On this basis,the transient dynamic analysis is carried out,which analyzes that a large vibration of the transmission box is produced under the limit condition.At the same time,the pure electric mode at 36km/h speed is chosen for harmonic response analysis to calculate the displacement of the transmission box nodes in the frequency domain,and a larger vibration displacement of the transmission box is produced near the fourth as well as the eighth natural frequencies of the box by analysis.Finally,The transmission box boundary element model is established by Virtual Lab Acoustics software.The node displacement of the transmission box which is analyzed by harmonic response is taken as boundary condition,and the radiated noise is predicted and analyzed to obtain sound pressure distribution of the transmission box.In addition,two kinds of noise reduction schemes are proposed: one optimize the design of the gears by using KiSS soft software as the simulation platform and another improves the transmission box designed by thickening and reinforcement.Through the simulation and comparison of the radiation noise before and after improvement,the improved sound pressure of radiated noise is reduced,and the rationality and feasibility of the noise reduction scheme are verified.