Research On The Process Of Press-fit And Retention Of Bearings Based On Finite Element Simulation

Bearing assembly quality affects its performance directly. There are many factors having influence on bearing assembly quality including material properties, interference, the precision of parts’ size, geometric tolerances, surface quality and so on. Currently, most process designers rely on manual process design experience to determine the process parameters. With respect to the problems of press-fit and retention affected by multiple factors, it is important to carry out the analysis on the procedure of press-fit process based on Finite Element Simulation for rational design of the press-fit process to assure assembly quality.The basic theory of bearing interference fit has been introduced. Analogy to two thick walled cylinder deformation and based on elasticity theory, equations of the interference range between bearing and housing under meeting elastic deformation conditions have been deduced. Through finite element model of bearing press-fit assembly, the change of press-fit force and radial displacements of parts have been predicted, the influences of material properties, friction coefficient and the amount of interferences on the press-fit force have also been analyzed.A special press-fit fixture and a press-fit bearing test rig have been designed. Press-fit test on bearing of 6201 with housing of 6063, Q235 and 45 has been carried out and the maximum press-fit force is tested. Based on Finite Element Simulation, the influences of press-fit force and stress between bearing and housing have been analyzed when shape error of the bearing’s outer ring or angle deviation of axes between housing and bearing exist.Analysis of balls’ motion rule on the retention tool has been analyzed by using dynamic simulation software. Finite element models of the process of retention and pull-off have been built. Dynamic simulation results of the balls have been applied as the boundary conditions of finite element simulation and the variation of normal pressure and Pull-off force in the retention of type A have been calculated through finite element simulation. The influences of different materials and different amount of interference on normal pressure have also been analyzed. Finite element models of the retention of type B and type C have been built to study the variation of stresses and radial displacement of assembles, Pulled off force with the change of time has also been attained.