A comprehensive sliding wear prediction method for planetary roller screw mechanism

The thread-pairs wear has a significant role in the transmission accuracy, operational stability and service life of planetary roller screw mechanism (PRSM). Nevertheless, the previous literatures still lack the investigation on the wear evolution of roller, nut and screw. Hence, an accumulative wear depth (AWD) prediction model is proposed for PRSM with reciprocating motion. The presented model is validated by the measured wear phenomena of thread pairs and the experimental results in the literature. The equivalent sliding wear experiment of PRSM is designed and the sliding wear coefficient of PRSM material is obtained by the equivalent sliding wear experiment. Considering the thread profile error caused by AWD of roller, nut and screw, the load distribution (LD) and sliding velocities on screw-roller (SR) and nut-roller (NR) sides are calculated. More importantly, the interactions between the AWD, LD and sliding velocity are investigated. Furthermore, the effects of axial load on the AWD, sliding velocities in contact regions and load distribution coefficient are analyzed.