Fatigue Analysis and Life Prediction of Recirculating Planetary Roller Screw Mechanism

The recirculating planetary roller screw mechanism, as a derivative of planetary roller screw mechanism, is a transmission mechanism that is engaged by the screw or nut thread and multiple circular groove rollers. To study the random vibration fatigue characteristics of the recirculating planetary roller screw mechanism, this paper established a finite element model of the mechanism based on fatigue failure theory, and conducted the dynamic analysis and fatigue life prediction. Firstly, according to the material stress-number of cycles (S-N) curve and Miner’s linear damage accumulation theory, fatigue analysis was carried out on the recirculating planetary roller screw mechanism using the related software, and fatigue results in the contact area and damage values at each node were obtained. Then, based on the developed four fatigue life prediction models, the obtained analytical solutions were compared with the simulated damage values. The results show that the resonance induced by the recirculating planetary roller screw mechanism at 3960 Hz causes the most damage to the mechanism. When the excitation frequency is the same, the area of maximum contact stress and minimum fatigue life is the same. Besides, the corresponding frequencies of the peak stress in the harmonic response analysis and that of the peak power spectral density in the fatigue analysis of the recirculating planetary roller screw mechanism are the same. This study can provide a theoretical guidance for the design and fatigue optimization of the recirculating planetary roller screw mechanism.