Effects Of Geometric Error Of Elements On Bearing Performance In Deep Groove Ball Bearing

This study is funded by National High-tech Research and Development Program of China (grant no.2009AA044901).As the technology of mechanical manufacture develops, the requirement of bearing accuracy is becoming higher and higher in many mechanical devices. In consideration of the fact that the geometric error of bearing component is inevitable, it is of great importance to have a research on the influence the geometry error of bearing exerts on the load distribution and precision. The following are the works in this thesis:(1) The structural characteristics and important concepts of deep groove ball bearing such as contact angle, curvature, goodness of fit, are introduced. The basic theories of rolling research, including the Hertz contact theory and rigid ring hypothesis, are introduced. Based on the Hertz contact theory, the relationships between contact load and contact stress and between contact deformation and contact stiffness of a rolling bearing are analyzed. These works provide solid theoretical foundation for the establishment of the deep groove ball bearing’s static model.(2) The five-degree of freedom static mechanical model of the deep-groove ball bearing is established, in which the roundness errors of inner and outer raceways and the diameter differences of balls are introduced. However, the geometric errors of bearing components aren’t considered in the traditional model of Harris. The6312bearing is analyzed respectively by two models and the results are very similar, which verifies that the model in this thesis is correct.(3) The emphasis of this thesis is placed on the influence the diameter differences and number of balls, radial clearance, radial and axial loads, roundness errors of inner and outer raceways have on deep-groove ball bearings’contact load as well as radial and axial non-repetitive run-out.The research indicates that the reasonable arrange of rolling elements with diameter differences and selection of harmonic order number of the inner and outer raceways’ roundness error could decrease the maximum contact load, bearing deformation and non-repetitive run-out, leading to an improvement of bearing capacity and accuracy.