Considering the influence of fluid structure interaction and cavitation on the actual deformation of hydrodynamic spherical bearing, the fluid-solid coupling analysis and multiphase flow simulation of spherical bearing for multi-degree-of-freedom motors are realized in this paper. The finite element simulation analysis of the model is carried out by using multi-physical field coupling software. In the study of bearings with and without effects of cavitation, the analysis shows that the peak value of oil film pressure and elastic deformation of spherical bearing decrease when cavitation effect is considered. The oil film pressure increases with the increase of eccentricity, rotation speed, viscosity and the decrease of the clearance between stator and rotor, which improves the bearing capacity of the bearing, but also intensifies the cavitation in the oil film divergence area and increases the gas volume fraction. And the oil film pressure test platform with different rotational speeds of the spherical rotor is set up, the measured experimental data are in good agreement with the numerical results. In the practical application of the motor, appropriate parameters should be selected, which is helpful to improve the working condition of spherical bearings, ensure the stable operation of bearings and prolong the service life.
