Analysis And Experiment Of High Horsepower Tractor Gearbox NVH Characteristics

This topic regarded great horsepower tractor gearbox as analysis object,studied the features of the vibration noise.Firstly using the transmission assembly as the subject;Secondly built and verified finite element model,analysis of its dynamics and acoustic properties;Finally used the gearbox shell and gears as an example for the noise reduction design by the finite element analysis software.1)Chose the horsepower tractor transmission as the research object,established three-dimensional model of box by UG three-dimensional modeling software,imported the model into ANSYS Design Modeler and used ANSYS Mesh module to divide the hexahedron mesh,set the material properties,the finite element model of gearbox is established.the modal analysis was carried out on the assembly simulation platform by ANSYS Workbench.Then do the modal test,compared the results with the simulation numerical to verify the accuracy of the simulation model;2)Studied the source and mechanism of the transmission vibration noise,used jiangsu donghua test modal test and analysis system for the vibration response experiment,the test system including DH5922 dynamic signal testing system,DHMA data acquisition and analysis system and DH131 E piezoelectric acceleration sensor,aimed at transmission assembly,testing vibration response analysis.Using UG software to establish finite element model of transmission,using dynamic analysis software ADAMS to different gear transmission gear rotational dynamics simulation,calculates the gear,and import it into the Virtual Lab of Noise & Vibration response analysis in the Vibration module,Vibration characteristics of transmission box.Compared the test results with the simulation results,verified the credibility of the finite element simulation;3)Noise test experiments are used to get the tractor transmission noise value,acoustic test equipments including: PCB acoustic sensors,PXI-1036 data acquisition box and PXI-6221 data acquisition card,embedded acquisition software Lab VIEW Singnal Express;4)transmission noise simulation analysis: imported the simulation results into the finite element model,which was compared with the experimental measured data.Used acoustics module of the acoustic simulation software LMS Virtual Lab,the dynamic simulation results of data as the model input,selected the boundary elementmethod(BEM),set up the corresponding acoustic analysis parameters for the noise simulation analysis of transmission,it is concluded that the vibration of transmission noise characteristic;Combined with the experimental measurement of transmission noise,calculated the transmission acoustic contribution amount in the transmission system by acoustic calculating formula and figure it,which can effectively visually reflect the gearbox inherent frequency and working frequency of the influence of noise;5)The design methods were proposed to reduce the transmission of vibration noise,analyzed the result of the vibration noise contribution,on the basis of theoretical analysis and test,in view of the transmission characteristic of the vibration noise analysis,altered the finite element model for structural modification,and verified the correctness of the noise reduction plan by comparison with the finite element simulation.