| Drive axle is an important part of drive system,it can achieve vehicle slowdown twist,transmission power,and drive in different speed by the driver,le the vehicle in good driving state.Drive axle is also one of the main vibration and noise sources when driving,In addition to the vibration caused by the surface vibration of the axle,the suspension plays a supporting role in the driving axle,the effect of vibration on the suspension,the effect of torsion and the impact of road surface,not only will affect the reliability of the automotive transmission system,but also easily lead to vertical and vertical vibration of the customer comfort sense,which is the most important indicators in customer satisifaction.The traditional method of controlling the noise of drive axle is mainly to carry out a number of tests and put forward the improvement on the basis of the experiment.The disadvantage is that the test items have some uncertainties,the test accuracy and the experimenter's experience is critical to success.Corresponding to the limitations of traditional methods,this paper uses CAD / CAE technology to analyze a popular medium-sized SUV.According to the market it has 90 Km /h-100 Km /h operation Vehicle noise anomaly feedback,combined with the drive axle assembly drive frame and frame modal analysis,the framework of the system components of the modal mode,rive axle parameter parameters were identified to optimize,put forward systematic improvement measures.In this paper,the gear noise mechanism is analyzed,the vibration method of the body and the common noise reduction method are identified.Then,the finite element model of the drive axle and the frame is established,On the basis of ensuring the main component size and assembly relation,simplified the original drive axle assembly model,Based on the theory of frequency response and noise transfer function,the transient response analysis of the drive axle assembly and the frame is carried out,and the state frequency and damping of the main components are analyzed.The excitation of the driving axle is generated by the gear meshing,identified the resonance frequency is around 480 Hz,through the axle and transverse stabilizer bar to the fourth suspension position of the frame,resulting in component frequency coupling;And then identify the drive bridge gear contact area does not meet the requirements of contact,causing the gear of the meshing impact is the vibration of the excitation source,while the vehicle test bench torque curve is unreasonable,failed in the rear axle test to identify the problem,armed with the simulation analysis and field verification to find the root cause of the whistle.On the basis of identifying the squeak cause,a series of optimization method is used to optimize the noise problem of the driving axle,and 13 kinds of intentionality optimization schemes are implemented on the fourth suspension of the frame,and the simulation results are analyzed respectively.From the choice of the fourth suspension position to increase a mass block to avoid the resonance,after NVH test and verification,this action can make the vehicle noise decrease 3d B.For design parameters of the axle improvement,during the development process,the parameters of the torque input parameters of the rear axle gantry are established.The meshing state of area of the drive gear is also optimized by the experimental design(DOE)method,with this actions implement efficiently,the rear axle noise abnormal sound issues get solved,and it is a good example in deal with vehicle squeak issues. |
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