Analysis Of Gearbox Vibration And Noise And Its Optimization

With the rapid development of shipbuilding industry,the transmission of gearbox is developing in the direction of high speed,high efficiency and strength.The power transmitted by the gear transmission system is increasing continuously and the gear speed is accelerating,which makes the vibration and noise of the gearbox more prominent.The vibration and noise generated during operation of the gearbox not only affect the working performance and working life of the ship but also endanger the physical and mental health of the workers on the ship.Therefore,it is of great research significance and practical value to reduce the vibration and noise of the marine gearbox by establishing the dynamic model of the gearbox to analyze its dynamic performance,finding out the vibration and noise sources during gearbox operation,and taking corresponding improvement measuresIn order to accurately simulate the gear transmission process,this paper uses the ADAMS collision contact function to establish the contact dynamics model of the gear.In order to make the gearbox model better reflect the performance of the gearbox,this paper considers the bearing excitation and gearbox.The dynamic model of the rigid-flexible coupling of the gearbox is established based on the contact dynamics model.The dynamic analysis of the rigid-flexible coupling model of the gearbox is carried out to analyze the influence of the rotation speed,meshing force and bearing support force.And other time-domain data,and through the discrete Fourier transform to convert it to frequency domain results,in the frequency domain through the gear meshing frequency to verify the peak position of each parameter curve.In order to study the influence of external load on the performance of gearboxes,this paper analyzes the changes of gear meshing force,input shaft torque under several different load changing conditions.In order to avoid the resonance of the gearbox during the working process,this paper establishes the finite element model of the gearbox and analysis the modal of the gearbox,obtains the natural frequency and natural vibration mode of the gearbox,and compares the gear input,output shaft frequency with the gear meshing frequency.In order to analyze the vibration response of gear box,this paper solves the harmonic response of gearbox based on modal superposition method in ANSYS Workbench,and gets the vibration velocity andvibration acceleration curve of each measuring point on the gearbox surface.In order to evaluate the vibration magnitude of the gearbox,this paper calculates the vibration intensity of the gearbox system through the vibration velocity of the measuring point and calculates the acceleration-level structure noise through the vibration acceleration of the measuring point.In order to analyze the radiation noise generated by the gear box,this paper establishes the acoustic boundary element model of the gearbox in Virtual.Lab Acoustics to solve the surface pressure and radiation air noise of the gearbox,and obtains the relationship between the noise size and the frequency.In order to find out the noise source of gearbox radiation noise,this paper divides the acoustics panel according to the structural characteristics of the gearbox.Through the analysis results of the contribution of the sound pressure panel and the acoustic power panel of the gearbox,the panel with larger noise contribution provides the basis for noise reduction optimization design of the following gearbox.In order to reduce the vibration of the gearbox,this paper aims to optimize the vibration of the gearbox by changing the wall thickness of gearbox structure based on multi-objective optimization method in ANSYS Workbench.In order to verify that the vibration of the gearbox is reduced after the vibration optimization,the vibration speed of the optimized measuring points is compared with original noise result.In this paper,the effect of the vibration reduction optimization model on noise reduction is verified by comparing the radiated noise at the site of the original model with the vibration reduction optimization model.In order to further reduce the radiation noise of the gearbox,based on the analysis of the contribution of the acoustic panel and the optimization model of the gearbox vibration,this paper puts forward two optimization gearbox structures program by reinforcing the walls and increasing the wall thickness.A better set of solutions is obtained by comparing the noise sizes of the two programs.The radiation noise of the program is compared with the original model noise to verify the noise reduction effect of the gearbox after the vibration reduction optimization and structural optimization.