Fatigue life analysis of cylindrical roller bearings considering clearance variation
Aiming at the traditional bearing life calculation method which is difficult to investigate the influence of working radial clearance on the life of cylindrical roller bearings,a theoretical calculation model of the working clearance of cylindrical roller bearings and a bearing life calculation model considering the working radial clearance were proposed.Firstly,after studying the influence mechanism of interference fit,centrifugal force,temperature,radial load and dynamic pressure lubricant film on radial clearance,the theoretical calculation model of cylindrical roller bearing working clearance was established.Then,according to the theoretical calculation model of bearing working clearance,the bearing life calculation model considering the working radial clearance was established by linking the maximum rolling element load with the bearing working clearance.Finally,the cylindrical roller bearing SKF N324 on the main shaft of SFW250-8/850 horizontal hydroelectric generator was taken as the research object,five original radial clearance groups defined in the standard were calculated based on the theoretical calculation model of bearing working clearance.Based on the bearing life calculation model considering working radial clearance,the load distribution and life of the five working radial clearance groups were analyzed to determine the optimal working clearance group.Lastly,the model results were compared with the calculation results of ISO/TS 16281:2008 and the simulation results of RomaxDesigner,verifying the reliability of the calculation model.The results indicate that the interference fit has the greatest effect on the radial clearance of bearings under light and medium load conditions,with respective changes of-30.768μm and-16.413μm.Temperature has the greatest effect on the radial clearance of the bearings under heavy load conditions with a variation of-16.866 μm.When the clearance value is-43 μm under light load condition,the number of rollers that can bear the load is 9,and the life reaches the maximum value of 48 187 h,the change of radial clearance will affect the distribution of contact stress and the number of loaded rollers of the bearing,which will affect the life of the bearing,and the optimal working clearance value of the bearing is different under different loads.The calculation results of the bearing life calculation model have an error of 3.48％with the calculation results of ISO/TS 16281:2008 and an error of 4.71％with the Romax simulation results.This model is closer to the actual working conditions,which can provide a reference for the bearing design,and can choose the appropriate clearance according to the actual working conditions to extend the bearing service life.
rolling bearingroller bearingsworking radial clearanceoriginal radial clearanceload distributionbearing life calculation modelinterference fitsshafting temperature fieldRomaxDesigner
NETL
NSTL
万方数据
