The Study On Load Sharing Properties And Optimization Of Large Scale Wind Turbine Gearbox

The energy shortage and environment pollution become increasingly serious. Wind power, as a clean and renewable energy, is paid great attention by the countries all over the world. In recently years, wind power of our country developed rapidly. But compared with the advanced level in the world, there's still great disparity on the design and manufacturing technology of large scale wind turbine.Wind turbine gearbox is an important component in the wind turbine. At present, the failure rate of wind turbine, especially the large-scale wind turbine which has been installed in our country is high. And the failure of the gearbox takes a large proportion. Therefore, systematic study on the large scale wind turbine gearbox can help reduce the failure rate of the gearbox, improve the performance and reliability of wind turbine. This has important significance for promoting the development of the wind power industry in our country.The large scale wind turbine gearbox generally includes planetary transmission. The load sharing properties directly affect the operating performance, reliability and life of the planetary transmission. So the load sharing properties and the key parts in the large scale wind turbine gearbox are studied. The main work and conclusions are as following.1. The static load sharing analysis model of large scale wind turbine gearbox is built, and the transmission errors are analyzed. The calculation method of static load sharing coefficient and the floating quantity of sun gear is acquired. The results indicate that the load sharing coefficient increase when the eccentric errors increasing. And the gear ring eccentric error has the maxmum influence on the load sharing properties. When equal parameters, the load sharing coefficient increase as the sun gear supporting rigidity rising.2. The dynamic load sharing property model is built, and the motion differential equation is derived. The dynamic load coefficient and dynamic load sharing coefficient is got after solve the motion differential equation with Fourier method. The result indicate that the sun gear ecentric error has the most remarkable effect on dynamic load sharing coefficient, the secondly is gear ring eccentric error, the planet gear eccentric error has the smallest influence.3. The optimal design model of large scale wind turbine is built to reach the objection of contact-fatigue strength of different stage approximately equal. The optimization of transimission parameters is implemented through genetic algorithm program. Compared with traditional design, the optimal design provides a method to obtain integral reasonable transmission parameters of large scale wind turbine gearbox.4. The fuzzy reliability model of planetary carrier is built, and the fuzzy reliability optimal design for planet carrier is carried out. Through the optimum design, the optimum solution of side wall thickness is got. The structure of the connection board between the two side walls is further optimized by finite element method. Compared with the original design, the weight of planet carrier reduced 32Kg. The largest displacement on original design is 0.845mm, the largest stress is 211MPa. After the optimum design, the biggest displacement decrease to 0.55mm, and the maximum stress reduced to 91.7MPa. By the structural optimum design, the deformation and stress is reduced, the rigidity is enhanced, and the influence on tooth engagement state from the deforming of planet carrier is reduced.5. Analyzed the load that acted on the gearbox of large scale wind turbine. The stress and deformation of different assembled gearbox are studied by finite element method. The results indicate that the biggest complex displacement on gearbox reaches 1.17mm, and it appears on the back district of the gearbox, especially near the left supporting hole and the bearing two. The largest stress on the gearbox is 99.68MPa, satisfy the design requirement. Mode analysis of the entire assembled gearbox is carried out, the first ten step natural frequency and corresponding vibrate mode are got. The results indicate that the first ten step natural frequency range from 233.2Hz to 526.8Hz, the natural frequency is higher than the value specified by the standard.6. The profile equations of shaping gear ring are deduced out by profile normal line method. The involute and transition curves are automatically generated through the macro function in Solidworks. And the three-dimension model is built. Based on the three-dimension model, the deformation and dedendum stress is studied. The results indicate that the largest deformation appear on the middle region of the addendum, the position of largest stress appears at the dedendum region of loaded tooth. As the curvature radius of transition curve rising, both the largest deformation and the largest dedendum stress reduce. With unchanged hole structure, the largest displacement and largest stress reduce as the rim thickness increase. And the influence of hole structure to the displacement of the ring gear is small, but the hole structure has significant influence on the largest stress of ring gear.