Improved Wear Profile Modeling of Planetary Roller Screw Mechanism With Thread Optimization

Abstract

A systematic process of matrices-based wear profile modeling and a new optimization approach for planetary roller screw mechanism (PRSM) was proposed in this paper to improve the anti-wear performance with varied thread geometries. The wear evolution characteristics of thread surfaces for convex–concave contact and convex–straight contact were captured by incorporating updated axial clearances originated from accumulated thread wear, which provides a new perspective to predict the wear process of PRSM. The results show that the wear depth in convex–concave contact is 22% shallower than convex–straight contact with 105 numbers of cycles, which suggests thread wear can be limited with plausible geometrical parameters. Further analysis showed that as the surface roughness increases, the true equivalent pressure, the plastic strain, and the maximum wear depth become larger. In addition, the effect of the surface textures on the tribological properties of threads is also discussed to improve the applicability of the proposed methodology.