Abstract
A multibody dynamics method has been developed to evaluate effects of bearing clearances on a planetary gear vibration. The numerical method solves the equation of motion by modal superposition using local floating frame. Gear mesh is calculated by numerical surfaces considering surface modification. Bearing clearance is modeled by nonlinear springs and dampers. Numerical examinations reveal that the radial clearance of the carrier affects the torsional vibration of the carrier. The clearance of the carrier should be small to reduce the excitation force of the carrier of the meshing frequency. Numerical results show that the unbalanced load sharing of the pinions increases the torsional vibration of the carrier.