Analysis Of Contact Stress And Fatigue Life Of Spindle Bearing In MW Wind Turbine

The rapid development of wind power industry has promoted the development of wind power special bearings industry.In recent years,China's wind turbine bearings in the design and manufacture have made great progress,But there is a big gap compared with the world's advanced level in the wind power bearings' life,carrying capacity,reliability and other aspects.Fan spindle bearing is a kind of special bearing for wind power.At present,the research on the contact stress and fatigue life of the spindle bearing is not deep enough in our country.In this paper,we took a MW turbine spindle bearing as the research object and analyze the factors that affect the contact stress and fatigue life of the bearing and explore the methods of improving bearing capacity and fatigue life of spindle bearing in order to provide reference for the design and manufacture of fan spindle bearings.The main contents of the thesis are as follows:1)On the basis of reasonable simplification of the fan model,the mechanical properties of the spindle bearings under load were analyzed.And then,we calculated the spindle bearing force in the rated wind speed,which bearing's radial force is 653660 N and axial force is 33643 N.The results of the force can provide the basis for the analysis of bearing contact stress and fatigue life.2)The spindle bearing static model of contact stress was analyzed based on ANSYS finite element analysis platform.And then,the stress distribution of the inner and outer ring raceway under the rated wind speed was solved,and the dangerous load position of the bearing was defined as the contact between the bottom roller and the bearing inner ring.On this basis,we also analyzed the influence of clearance and contact angle on bearing contact stress and got the conclusion that the appropriate negative clearance and the smaller contact angle can improve the bearing capacity of the spindle bearing.The spindle bearing structure can be optimized according to this conclusion.3)The fatigue life of the spindle bearing was calculated at rated wind speed based on Fe-safe fatigue life software.The life expectancy of the spindle bearing meet the requirement of the fan's 20 years design life of rated.In order to make the spindle bearing can meet the requirements of the service life under the more harsh conditions,this paper further discussed the influence of bearing surface roughness and bearing residual stress on its life.The fatigue life of the bearing under different surface roughness and different residual compressive stress was calculated.The results showed that improving the surface roughness of the bearing and introducing favorable residual compressive stress to the inner and outer ring raceway surface can greatly improve the fatigue life of the bearing.The research contents of this paper can provide appropriate reference for the design and manufacture of fan spindle bearings and have some guiding significance for improving the performance of the spindle bearing and the power efficiency of the entire fan.