Dynamic And Reliability Analysis Of Pitch Reducer For Megawatt Wind Turbine

As the most popular transmission at present days, multi-stage planetary gear transmission was used widely in many areas. As time went by, improving the reliability and service life of multi-stage planetary gear transmission by means of dynamic optimization had become more and more important. In this thesis, we studied mainly on the dynamic characteristics of pitch reducer for megawatt wind turbine and the dynamic changes of modification model after tooth profile correction. Meanwhile, on the base of reliability theroy, the system reliability of pitch reducer transmission was analysised. The main work of this thesis was completed as follows.The system dynamic model was established with the lumped mass method. Then, we listed out the differential equations of system motion and the coefficient matrixes. And, the Model Analysis Method was introduced to solve the differential equations of system motion.The time–varying mesh stiffness model was established while the mesh stiffness was calculated that based on Ishikawa formula. After that, we got the pitch reducer set's natural frequency and natural vibration type when it worked under the time–varying mesh stiffness. At the same time, using the Fourier Transform to simplify the time–varying mesh stiffness model to lower the difficulty of equation solution, we got the system response both with and without the damping of pitch reducer for megawatt wind-driven generator. The dynamic load was also introduced to measure the changes between different models in ABAQUS.The tooth profile correction theory and methods were discussed. After been corrected by line long correction, line short correction and curve correction, the changes of dynamic response between the non-corrected model and correction's were analysised. With the help of ABAQUS, we compared the dynamic load of different models to research on the influence of tooth profile correction changes on system dynamic characteristics.At last, the system reliability calculation formula was obtained on the basis of the pitch reducer system reliability theroy. After the reliability comparison, we discovered that the manufactured pitch reducers had reached the same level of foreign products in main function.