Research On Factors Influencing Accuracy Life Of Four-point Contact Ball Bearing

Rolling bearing is not only an irreplaceable important equipment in advanced manufacturing industry,but also an important indicator to measure the quality and technology level of manufacturing industry.Its performance directly affects the safety and stability of the whole machine.Four-point contact ball bearing is widely used in automobile,mining machinery,machine tools,robots,spacecraft,precision instruments,electronic computers,construction machinery and textile machinery.With the rapid development of modern industry,all walks of life put forward higher requirements for bearing capacity,dynamic characteristics,reliability,accuracy and so on.Therefore,it is of great significance to study the factors influencing precision life of four-point contact ball bearing.The rotation accuracy,dynamic performance,dynamic accuracy and precision life of four point contact ball bearing are studied in this paper.It provides some theoretical reference and experimental guidance for the important problems such as rotation accuracy prediction,dynamic accuracy evaluation and accuracy life research of four-point contact ball bearing.Firstly,the factors that affect the rotation accuracy of four-point contact ball bearing were studied.The mathematical model of the transformation from three-dimensional contact curve of steel ball and inner and outer rings of four-point contact ball bearing to two-dimensional plane contact curve of that was established.A numerical method for calculating the rotation accuracy of the bearing considering the roundness errors of inner and outer raceway was proposed based on the mathematical model.The numerical calculation program was compiled with MATLAB to realize the simulation solution of the rotation accuracy of the four-point contact ball bearing.The influence of amplitude and harmonic order of roundness error of the inner ring,amplitude and harmonic order of roundness error of the outer ring,diameter deviation of steel ball and the number of ball on rotation accuracy of the bearing was studied.Secondly,the dynamic performance of four-point contact ball bearing was studied experimentally.According to the drawing of RU110 S four-point contact ball bearing,the test fixture was designed.The single factor control variable method was used to test the influence of rotational speed of spindle,axial load and radial load on the radial vibration of bearing,temperature rise of outer ring of bearing and the average torque of spindle.The relationship between the working condition parameters and the dynamic performance index of the bearing under the specific test conditions was obtained by using the Origin curve fitting.The dynamic performance orthogonal test of four-point contact ball bearing was carried out by using the self-made test machine of dynamic performance of rolling bearing in the laboratory.Thirdly,the comprehensive evaluation of dynamic accuracy of four-point contact ball bearing was carried out.Based on the test data of dynamic performance of four-point contact ball bearing,the principal component analysis method was used to extract the characterization quantity of dynamic accuracy of bearing.The range analysis and variance analysis were carried out to study the influence of rotational speed of spindle,axial load and radial load on the characterization quantity of dynamic accuracy of bearing.Finally,the accuracy life of four-point contact ball bearing was studied experimentally.Based on the definition of bearing accuracy and bearing life,a relatively comprehensive evaluation method of accuracy life of bearing was put forward.According to the results of bearing dynamic performance test,the judgment criteria of accuracy life of bearing was formulated.Using the orthogonal test method to design the experiment,the precision life of four-point contact ball bearing was studied experimentally,and the range analysis and variance analysis were carried out for the test data of precision life of bearing.