Research On Motion Equation And Reliability For Yaw And Blade Bearing In Wind Turbine

Yaw and blade bearing are chooseed as the research object in this article,aiming at movement characteristics of yaw and blade bearing the motion equation is constructed for accurately working out their loads,to provide theoretical basis for calculating their lifetime. The common failure forms of yaw and blade bearing are researched and their reliability are further analyzed. Force analysis about yaw bearing is more complex,especially during the movement process,according to the characteristics that it influenced by axial force, radial force and overturning moments at the same time,the single four-point contact ball bearing is generally used in yaw bearing but the double row four-point contact ball bearing is used in blade bearing.Aimming at the application condition of wind turbine bearing,loads distribution model of positive clearance single four-point contact ball bearing is discussed which forced by axial force,radial force and overturning moments at the same time;Aiming at the design requirements of negative clearance is generally adopted in the blade baring,the relationship between elastic deformation and negative clearance is studied,and the equation of rings deformation is established under the condition of no-load and negative clearance ; The loads distribution are researched during movement of yaw and blade bearing,and two methods are discussed to calculate the lifetime of yaw and blade bearing,one is load curve and the other is equivalent dynamic load and then the two methods are done comparison with each other.The method for estimating yaw and blade bearing fatigue life is researched.Variety invalidation forms of yaw and blade bearing are summarized,and checking method about key position of yaw and blade bearing are given, such as raceway, bolt and gear.Motion equations of yaw and blade bearing are finished to construct in this article,during this process according to different working conditions of yaw and blade bearing their motion equations under no-load and load are separately builted. According to the motion equation we can more accurately calculate the inner load distribution of different yaw and blade bearing and calculate contact stress of the maximum load roller,to establish theoretical foundation for calculating lifetime and analysing reliability of yaw and blade bearing.