| With the continuous development of wind power generation technology and the increase of maintenance and downtime costs,the requirements for the motion accuracy,stability,reliability and service life of gear transmission mechanism are becoming higher and higher.The influence of the dynamic parameters of the mechanism on the non-linear dynamic characteristics of the transmission system has become a research hotspot at present.The comprehensive performance of the output high-speed shaft in the wind power gearbox transmission system also affects the transmission accuracy and reliability of the system.For the gearbox of wind turbine,in the high altitude environment of random wind speed,the comprehensive performance of dynamic parameters of transmission system and output high-speed shaft is particularly important to the stability and accuracy of transmission system.Based on the first planetary two-stage parallel gearbox,this paper takes two-stage parallel helical gears and output high-speed shaft as the research object,studies the influence of dynamic parameters on the non-linear dynamic characteristics of transmission system and the comprehensive performance of output high-speed shaft,and provides theoretical reference for the design and optimization of this type of wind power gearbox.The main research contents and results are as follows:Firstly,the mechanism of various excitations in the transmission system is elaborated,the calculation formula of the time-varying meshing stiffness of spur gears is improved,the formula of calculating the average meshing stiffness of helical gears is established,and the average meshing stiffness of two pairs of helical gears is obtained.Then,the time-varying meshing stiffness is numerically simulated by Fourier counting.Error and damping are analyzed simply and approximated by numerical simulation.Secondly,a two-stage pure torsion nonlinear dynamic model of helical gears with backlash,time-varying meshing stiffness,damping and error is established.Based on the model,a dynamic differential equation is established by Newton's law and solved by Newmark numerical method.The results of the system's non-linear dynamic response are obtained.The influence of backlash,damping and error on the non-linear dynamic characteristics of the system is analyzed by using the time history diagram of meshing force and displacement,phase diagram and FFT diagram,and the law of the influence of dynamic parameters on the force and motion state of the gear is obtained.Thirdly,the influence of speed,clearance and clearance variation on contact force of two helical gears is discussed.The contact force variation of two gears from start-up stage to stable stage is analyzed with three speeds: low speed,medium speed and high speed.There are single pair of gear clearance change and two pairs of gear clearance change at the same time in transmission system.According to the clearance change mode and clearance dynamic response analysis of transmission system,the influence law of clearance change on gear contact force,the influence law of different clearance change mode on gear contact force and the influence law of different clearance change mode on gear contact force with the change of clearance are obtained.Two pairs of gears with different clearances are analyzed by Ansys,and the reasonable meshing clearance range of gears is determined by simulation results,which can provide reference for the design and processing of gearboxes.Finally,in the analysis of the comprehensive performance of the output high-speed shaft of the transmission system,the influence of bearing support stiffness on the frequency and modal of the shaft and the influence of speed on the whirl of the shaft node are studied.Combining with the modal analysis of the high-speed shaft in Ansys,the range of support stiffness,the range of speed and the position prone to deformation are reasonably selected.According to the results,the basis for the optimal design of the shaft is provided. |
PDF Full Text Request