Elastohydrodynamic lubrication analysis with eccentric errors for planetary roller screw mechanism

The lubrication characteristics of planetary roller screw mechanism (PRSM) with eccentric errors are investigated in this work. And the formulas of entrainment velocities with eccentric errors are derived. The film thickness and pressure distributions of screw-roller (SR) and nut-roller (NR) thread pairs are analyzed. It finds that the film thickness of SR thread pair is larger than that of NR thread pair. Moreover, the effects of eccentric errors on comprehensive meshing radius, entrainment velocities and lubrication characteristics of SR and NR thread pairs are discussed. The results show that the eccentric errors have significant effects on lubrication characteristics of PRSM.