Study On Prediction For Rotational Accuracy Of Cylindrical Roller Bearings

Rolling bearing is an indispensable key component in mechanical equipment.Its main function is to support the shaft and parts,to bear load,and to maintain the normal working position and rotary accuracy of the shaft.As modern mechanical equipment is gradually developing towards high precision,high performance and high reliability,which requires higher rotational accuracy of rolling bearings,and it presents stringent requirements on the design level of high-precision rolling bearings.However,due to various factors,the research level about rotational accuracy of rolling bearings has lagged behind the engineering application.The accuracy design of rolling bearings largely depends on the accurate grasp of the influence of geometric errors of bearing parts on rotational accuracy of rolling bearings.Therefore,it has extremely important theoretical value and engineering significance to investigate the transmission mechanism of geometric errors of bearing parts and rotational accuracy of rolling bearings for improving the design level of high-precision rolling bearings.taking cylindrical roller bearings as the research object,this paper,fully considering the influence of geometric errors of bearing parts,carries out prediction study on the rotational accuracy of rolling bearings for the engineering requirements of high-precision bearing design and the existing problems.The work is summarized in detail.(1)The prediction methods of rotational accuracy of the inner and outer rings of rolling bearings are established respectively.Based on the relationship between bearing geometry and motion,considering the geometric errors of the inner raceway,the outer raceway and roller and the influence of the change of contact point between rollers and raceway caused by the geometric errors of bearing parts,the prediction method of rotational accuracy of the inner ring and the prediction method of rotational accuracy of the outer ring are established respectively.It is realized to predict rotational accuracy of rolling bearings through the parameters and geometric errors of bearing parts.(2)The method for measuring rotational accuracy of the inner ring of cylindrical roller bearings is presented.The measuring device for rotational accuracy of the inner ring of cylindrical roller bearings is designed.The measurement technique and experimental flow for rotational accuracy of the inner ring are proposed.The measurement for rotational accuracy of rolling bearing can be realized.Measuring the dimension and geometric errors of bearing parts,the rotational accuracy of rolling bearings is predicted under the same working conditions of test bearings through the proposed prediction method.The theoretical results are compared with the experimental results.The correctness of the proposed prediction method of rotational accuracy of the inner ring are supported by experimental results.(3)The influence of geometric error of bearing parts and number of rollers on rotational accuracy of rolling bearings is discussed.Based on the proposed prediction method,the influence mechanism of rotation accuracy of rolling bearings is investigated under different geometric errors of the inner and outer raceways and rollers and roller number.The mapping relationship between geometric errors of bearing parts and the number of rollers and rotary error of rolling bearings is established.The effect of geometric errors of bearing parts on rotation accuracy of rolling bearings is revealed.(4)The rotary error of the inner ring is investigated under load and geometric error.Considering the geometric errors of bearing parts and change of load action direction between roller and raceway,the calculation method of bearing inner ring rotation error is established.The relationship between geometric error,elastic deformation of bearing parts,number of rollers and rotary error of the inner ring is discussed.The results are compared with the rotary error of the inner ring under no-load condition.The evolution law of rotary error of the inner ring from no-load state to loading state is revealed.(5)The statistical prediction method of rotational accuracy of rolling bearings based on Copula function is presented.The Copula function between distribution of rotary error of bearings and distribution of geometric errors of multi-element bearing parts is constructed.The prediction method of distribution of rotational accuracy of rolling bearings based on Copula function are proposed.The dependence relationship between distribution of geometric errors of bearing parts and distribution of rotary error of bearings is discussed.The study shows that,the single roundness error of the inner raceway,the outer raceway and rollers has significant effects on rotational accuracy of rolling bearings,and the influence level depends on relationship between the roundness errors of bearing parts and the number of rollers,but the roundness error of the rollers with the odd order is excluded.The coupling effect among roundness errors of the inner raceway,the outer raceway and rollers reduces significantly rotational accuracy of rolling bearings,and the decrease level depends on the orders of roundness errors of bearing parts and the number of rollers.Compared with the rotary error of the bearing under no-load condition,the existence of radial load does not change the influence law of geometric error of bearing parts on rotary error of rolling bearings.Only the rotary error of rolling bearings increases or decreases with the change of the orders of roundness error of bearing parts.The geometric errors of the inner raceway,the outer raceway and rollers have a significant positive correlation with the rotational accuracy of rolling bearings.The distribution interval of geometric error of the inner raceway,the outer raceway and rollers has a significant impact on the distribution of rotational accuracy of rolling bearings.When the bearing parts with different geometric accuracy grades are combined,the probability of an accuracy grades of the bearing is higher.In this paper,investigating the relationship between geometric error of cylindrical roller bearing parts and bearing rotation accuracy,the prediction method for the rotational accuracy of rolling bearings is proposed,and the rotational accuracy of roller bearings is predicted by the geometric errors of bearing parts.The correctness of the proposed prediction method is verified by experimental results.The prediction method of distribution of rotational accuracy of rolling bearings based on Copula function is proposed.The statistical analysis method for the distribution of rotational accuracy of rolling bearings is developed.According to the distribution range of geometric errors of bearing parts,the probability of the rotational accuracy of rolling bearings with different precision grades can be predicted.The effects of geometric errors of bearing parts on rotational accuracy of bearings are obtained,and the mapping relationship between geometric errors of bearing parts and the number of rollers and rotational accuracy of rolling bearings is established.The influencing factors of rotational accuracy of rolling bearings are obtained.Especially,the rotational accuracy of rolling bearings can be effectively improved by controlling the roundness error of bearing parts whose order is an integer multiple of the number of rollers.The research results in this paper can not only predict the rotational accuracy and its distribution of rolling bearings,but also provide theoretical basis for the distribution and control of geometric errors and geometric accuracy of bearing parts.It is helpful to improve the design level of high-precision rolling bearings and develop high-precision rolling bearings.