Vibration-noise Analysis And Optimization Design Of Automobile Drive Axle

As one of the main vibration and noise sources of the automotive transmission system,the vibration and noise level of the drive axle has always been an important consideration in the automobile development and design.Therefore,the vibration and noise mechanism of drive axle and vibration and noise reduction technology have been researched by domestic and foreign scholars.This paper takes the drive rear axle assembly of a front-engine-and-rear-wheeldrive car as the specific reserch object,firstly,the vibration and noise mechanism and transfer path of drive axle are analyzed briefly.Then,based on the lumped parameter method,the coupling vibration theory model of gear-bearing system considering the influence of internal and external excitation and the bearings contact vibration is established.The dynamic response of the drive axle gears and the outer ring of each supporting bearing is obtained by numerical solution of the coupled vibration model of the gear-bearing system.Secondly,the Adams virtual prototype model of drive axle gear-bearing system is established,the correctness of the coupling vibration theory model of gear-bearing system and the numerical solution is verified by the dynamic simulation.The dynamic simulation also provides another way for the dynamic performance analysis and development of the drive axle.Thirdly,the finite element model of drive axle housing is established,and the natural frequencies and modes of drive axle housing within 2000 Hz are obtained by the constraint modal analysis.On the basis of modal analysis,the dynamic response of each bearing outer ring is applied to the bearing position of the drive axle housing.Through frequency response analysis,the vibration response of the drive axle housing is obtained and the dynamic characteristics of the drive axle housing are analyzed.On the basis of the frequency response analysis,the boundary element method is used to simulate the radiated noise of the drive axle,the value and distribution of the acoustic radiation of the drive axle housing under the gear meshing impact and main modal frequency are predicted.In addition,the sound insulation performance of the drive axle housing is analyzed,and it is shown that the transmission noise of the drive axle cannot be neglected at some specific frequencies.Finally,through the test of the vibration and noise of the drive axle,the coupling vibration theory model of the gear-bearing system and the numerical simulation model of the drive axle housing acoustic radiation are verified in this paper,and according to the vibration and noise prediction flow of the drive axle,the gear clearance and the bearing preload parameters and the drive axle housing are optimally designed.The results show that the vibration and noise of the drive axle can be reduced effectively by properly reducing the gear clearance and increasing the bearing preload and the thickness of the rear cover.In a word,this paper establishes the complete and reliable coupling vibration model of drive axle gear-bearing system and an acoustic radiation prediction model of drive axle,that makes it possible to predict the drive axle dynamic characteristics and radiated noise at the beginning of the design and development and then to design reasonable gear system parameters and the drive axle housing.The research results provide a reference for the development and design of the drive axle and the vibration and noise reduction.