Dynamics And Crack Fault Analysis Of 5MW Wind Turbine Gearbox

Gearbox is an important transmission component in doubly fed wind turbine,and the research of high power unit is the mainstream of today.Aiming at this problem,the design of 5MW wind turbine gearbox is proposed,and the static school nuclear and dynamic performance of the gearbox is analyzed.It is found that the solar gear of the first planetary gear train has a high probability of cracking when the wind turbine gearbox is running.The statics of the first planetary gear train is studied,and the influence of different cracks on the time-varying meshing stiffness of the gear pair is analyzed.First of all,according to the existing information to determine the design requirements of the gear box;Determine the transmission scheme,using two stage2K-H type planetary gear train and fixed shaft gear train combination of the transmission form;According to the design requirements and methods of planetary gear train and fixed shaft gear train,the gear parameters are calculated and theoretically checked.According to the parameters and force requirements of the gear,determine the size of the planetary frame and shaft structure,and choose the bearing type.Secondly,in order to improve the calculation efficiency and accuracy,the planetary frame is set as a flexible body,and the rigid-flexible coupling model is established.Input the load spectrum required by the gearbox design,and conduct static analysis on the transmission system to obtain the contact stress,bending stress and safety factor of each gear pair.Compared with the theoretical calculation,the maximum relative error is less than 10%,which indicates the accuracy of the calculation results.The AGMA6006 standard wind power load spectrum was input into the software,and the results showed that the maximum damage of each bearing in the design life was 80%,indicating that the bearing was properly selected.Thirdly,the dynamics analysis of the gearbox is carried out.The first ten order mode shapes and frequencies of the two planetary frames are obtained.The meshing frequency of the gear of the planetary train is obtained by theoretical calculation.The meshing frequency of the gear is far less than that of the corresponding planetary frame,which shows that the design of the planetary frame is reasonable.The calculation method of transmission error of gear pair is summarized,and the displacement and transmission error of each gear pair along the direction of the meshing line are obtained.It is found that the variation law is related to the parameters and the force of gear pair.The acceleration response curve and change rule of each bearing are obtained.The speed range of the input shaft of the gearbox is less than the speed corresponding to the peak value of the acceleration response,which further explains the rationality of bearing selection.Finally,modeling,hexahedral meshing and statics analysis are carried out for the first planetary gear train.The results show that when the first planetary gear train is running,the stress and strain are concentrated near the end face of the tooth root of the solar gear.Set up 20 different degree of gear crack fault,divided into the penetrability and the penetrability of crack,the crack depth and width with a parabolic fitting respectively,using the method of limited by time-varying meshing stiffness of gears,and found the regularity of crack shape and stiffness degradation,for gear crack fault impact on the meshing characteristics of the research provides the basis.