Carrying Capacity Analysis Of Single-row Four-point Contact Ball Slewing Bearing

Single-row four-point contact ball slewing bearing, a kind of large bearing,can carry simultaneously axial load, radial load and overturning moment, whichis widely used in all kinds of engineering machineries, military equipments,recreational facilities and other fields with the characteristics of compactstructure, stable motion, high precision and strong carrying capacity. The loadsand motion are transferred through the point contact among inner ring, outerring and rolling element. Because of the large loads and small contact area, thestress of contact area is very large. The carrying capacity and service life ofslewing bearing depend on the contact capacity which is the basis of researchingon slewing bearing. In this paper, the capacity of slewing bearing has beenanalyzed by its contact capacity. The main works are as follows:Based on Hertz contact theory, the length of the semi-major and semi-minoraxis of the contact ellipse, the contact area and the maximum contact stressamong inner ring, outer ring and rolling element are calculated. The elasticfinite element contact model and the elastic-plastic finite element contact modelof slewing bearing are built and solved. The stress and strain neph ograms ofvarious parts are got at the same time. Combined with the actual workingconditions, the failure reasons of the raceway are analyzed. The contact analysisof slewing bearing does not meet the basic assumptions of Hertz theory. Bigerrors by using Hertz theory analysis are found by analyzing the results of threecontact analysis methods. The elastic-plastic finite element contact model havea more outstanding performance than the elastic finite element contact model,for taking layering of raceway material properties and plastic deformation intoaccount, closer to reality. Therefore, it is the elastic-plastic finite elementcontact model which should be used for the contact analysis of slewing bearing.Considering the different results of different analysis approachs, theallowable contact stress, which is calculated based on Hertz contact theory, isnot suitable for evaluation of finite element calculation results. The allowablecontact stresses, which are suitable to evaluate the results of Hertz t heory,elastic finite element model and the elastic-plastic finite element model, are gotby the pressure experiment between ball and plate. Furthermore, in order to improve the efficiency and accuracy ofthree-dimensional modeling, a fast modeling software of single-row four-pointcontact ball slewing bearing is developed by using Visual Basic6.0for CATIA.In order to make the finite element analysis results more reliable, the slewingbearing is fully divided into hexahedron meshes by the technology of a utomatictransition encryption of hexahedral mesh, which is developed in HYPERMESH.It can reduce the calculation of the model and improve the accuracy of themodel.