Vibration Noise Analysis Of Gearbox Based On EMI Technology

The vibration and noise generated by gearboxes not only has a detrimentaleffect on its service life,but also detrimentally affects the environment and lif e around it;thus,it is essential to investigate the vibration and noise of gearbo xes.The focus of this paper is a particular type of gearbox,with the purpose ofconstructing a gearbox dynamics model,finite element model,and acoustic bou ndary element model to analyze its vibration and noise characteristics,uncoverin g the vibration and noise sources in its operation,and implementing correspondi ng improvement measures to reduce the vibration and radiation noise.In this pape r,the following aspects of work are carried out:(1)The piezoelectric effect of PZT-4,the piezoelectric equation,and the electrical conductance and impedance equations of the SMD system driven by PZT-4were derived,and the coupling model of the gearbox and PZT was established;the basic principle of vibration noise and noise transmission path of the gearbox were introduced,and the vibration characteristic equation of the gearbox was analyzed theoretically.(2)The vibration characteristics of the gearbox are analyzed.To begin,a thorough examination of the fundamentals of modal analysis is conducted,followed by the formation of a finite element model and the execution of modal analysis.Utilizing finite element analysis software to ascertain its inherent frequency and vibration cloud,thus circumventing the resonance of the gearbox during operation,a dynamics simulation analysis of the internal gear transmission system is conducted.This simulation is based on Herz theory in the dynamics analysis software,and the gear mesh force and bearing support reaction force are then determined.The peak frequency points of the mesh frequency of the gear,along with the frequency domain outcomes of each parameter,were all taken into account during the transmission of the gear.obtained from the dynamics simulation are compared and analyzed to verify the a ccuracy of the simulation model;finally,the harmonic response analysis of the finite ele ment model is carried out by the modal superposition method to obtain the vibration sp eed and vibration acceleration of the gearbox.(3)Theradiated noise of the gearbox is analyzed.Using the acoustic module in the simulation software,an acoustic finite element model of the gearbox was established.Subsequently,acoustic simulation analysis was conducted to determine the alteration in the surface sound pressure level of the gearbox.The analysis revealed that the surface sound pressure and the radiated noise of the gearbox reached their peak near 2250HZ(triplemeshing frequency).Afterwards,the acoustic panel’s contribution was computed and scrutinized to determine which panel had a bigger acoustic contribution,which supplied the data foundation for the succeeding gearbox vibration and noise reduction optimization experiments.(4)The Fast Fourier Transform module of LABVIEW processes the data signal from the acoustic pressure frequency domain image,which has been designed and constructed to conduct acoustic excitation experiments on the gearbox’s acoustic test platform.The impedance analyzer is then used to conduct impedance modal experiment s on the gearbox,and the experimental results are compared with the simulation experi mental results to verify the correctness of the simulation model and determine the reso nance band range of the gearbox.