Kinematics Modeling and Pitch Diameter Modification of the Standard Planetary Roller Screw Mechanism

Aiming at the problem of precise parameter matching of the planetary roller screw mechanism (PRSM), kinematics modeling and pitch diameter modification methods of the screw are studied in this paper. Firstly, the kinematics model of the standard PRSM is established using algebraic methods, which reveals the matching relationship of screw parameters among the screw, the roller and the nut. And the design criterion of the standard PRSM is established. Based on the meshing principle of space cross threads between the screw and the roller, constraint equations are further completed, and the exact pitch diameter of the screw is determined. Finally, the motion and static simulations of the PRSM are performed. The results show that the kinematics model and the pitch diameter modification method can effectively ensure the stable transmission and assembly process of the standard PRSM.