Mechanism of vibration suppression induced by roller pitch diameter modification in planetary roller screw mechanism

To elucidate the intrinsic mechanism of vibration suppression induced by roller pitch diameter modification in planetary roller screw mechanism (PRSM), a coupled dynamic model incorporating modification effects is developed. The influence of different modification magnitudes on the vibration response of key components is systematically investigated. First, based on helical surface contact theory, a thread contact model considering roller modification is established. The clearance distribution induced by the modification is introduced into the load distribution analysis as the initial condition. Subsequently, Hertzian contact theory is employed to obtain the non-uniform load distribution. A lubricated sliding friction model for the roller–screw interface is further established and incorporated into the dynamic equations as an excitation source. By analyzing the spatiotemporal evolution of friction forces under different modification levels, the vibration suppression mechanism is clarified. Finally, the proposed model is validated through model degeneration analysis and experimental comparisons, confirming its reliability and accuracy. However, the synergistic vibration suppression effect of gear pair modification and thread pair modification was not considered in the present study. Future work will focus on establishing a coupled modification model of the thread pair and gear pair to further reveal the vibration suppression mechanism and vibration characteristics of PRSM.