Investigation on contact behavior of planetary roller screw mechanism considering thermal deformation

Abstract

Previous thermal studies on planetary roller screw mechanism (PRSM) are mainly concentrated on frictional heat without the consideration of external thermal loads. However, the contact behavior of planetary roller screw mechanism varies greatly during the operation process. In this paper, a calculating method for frictional heat of planetary roller screw mechanism based on friction torque is proposed, and a transient thermal model is established to analyze the heat transfer of planetary roller screw mechanism at multiple thermal conditions. Then, an analytical method is introduced to investigate the temperature and the equations of its influences on the thermal deformation are derived. The influences of temperature distribution on the clearances and contact positions of the mating thread surfaces is studied as well. We found that the frictional heat, thermal resistance and thermal loads can significantly alter the temperature distribution consistency. The results indicate that the load-bearing capacity of planetary roller screw mechanism is greatly affected by the temperature differences between the planetary roller screw components. By allowing comprehensive thermal simulation, the proposed model can be utilized for PRSM optimization design.