Research On Performances And Structural Parameters Of Slewing Bearing With Flexible Supporting Structures

Compared with common rolling bearings, a large slewing bearing have its two notable features—the one is that its working speed is much slower; The other one is that it has insufficient and uneven supporting stiffness, so the deformation of its supporting structure influences its load distribution thus affecting its performance in some degree. Consequently, it is necessary to develop a method and procedure for analyzing the performances of a large slewing bearing specially. Supported by the "Liaoning province science and technology innovation projects (No.201303006)", the research on mechanical characteristics, static capacity, fatigue life of the slewing bearing, structural parameter optimization, and the strength of the connecting bolt in slewing bearing are carried out. The main content of the paper is as follows:In order to get the load distribution more accurately, in this paper, a new analysis model is established to calculate the load distribution of a bearing with flexing ring and supporting structures. Introducing the supporting structures stiffness, the equilibrium equations are derived, thus the static theoretical analysis model is established.A finite element model containing the supporting structures is established. It is necessary to carry out a fine meshing in the ball-raceway contact zone, which results in a large calculating scale. The method deleting original coarse elements then recreating fine meshing elements is adopted. On the guarantee of accuracy, this method greatly reduced the number of element and node in FEM. The load distribution results of the above two methods have been highly correlated, which preliminary verified the correctness of the theoretical analysis model. Additionally, the computational efficiency of the analysis model is much higher than that of the FE contact model.The static capacity and its analysis method are introduced briefly. Based on the analysis model, The effect of the bearing structure parameters on the load distribution is studied, the results of which form the constraint conditions of bearing parameters. Using the constraint conditions and taking the static capacity as objective function, the bearing parameters’ optimization model is established and solved by means of genetic algorithm. The static capacity of the bearing is effectively improved.Based on the load distribution results of the analysis model, according to the international standard, the fatigue life time of the bearing is calculated. The effects of bearing parameters and the flexibility of supporting structures on bearing life time are studied and effective measures to improve the fatigue life of slewing bearing are put forward.Simplified FE model of connecting bolts in slewing bearing considering the deformation of supporting structures and the contact force on the ring’s raceway are established. In the simplified FE model, the ball-raceway contact pair is replaced by a nonlinear spring and the bolt-parts contact pair is replaced by a beam element, which greatly reduces the computational cost. The simplified FE model and traditional formula method are used respectively to obtain the working load of bolts, then the static strength of a single bolt is checked.The analysis method and the results of the research has guiding significance to the design of large slewing bearing.