Kinematics of Planetary Roller Screw Mechanism considering Helical Directions of Screw and Roller Threads

Abstract

Based on the differential principle of thread transmission, an analytical model considering helical directions between screw and roller threads in planetary roller screw mechanism (PRSM) is presented in this work. The model is critical for the design of PRSM with a smaller lead and a bigger pitch to realize a higher transmission accuracy. The kinematic principle of planetary transmission is employed to analyze the PRSM with different screw thread and roller thread directions. In order to investigate the differences with different screw thread and roller thread directions, the numerical model is developed by using the software Adams to validate the analytical solutions calculated by the presented model. The results indicate, when the helical direction of screw thread is identical with the direction of roller thread, that the lead of PRSM is unaffected regardless of whether sliding between screw and rollers occurs or not. Only when the direction of screw thread is reverse to the direction of roller thread, the design of PRSM with a smaller lead can be realized under a bigger pitch. The presented models and numerical simulation method can be used to research the transmission accuracy of PRSM.

Bond graph-based dynamic model of planetary roller screw mechanism with consideration of axial clearance and friction

“…In this study, the bond graph model of the PRSM was implemented using the 20-sim software package which is a general bond graph simulation software developed by the control laboratory of Twente University in Holland, and the results were compared with those of a numerical model developed using the Adams software (the modeling method and analysis steps of Adams model can be found in reference 19 ). Straightforward model validation could be a very difficult task because of the many parameters involved in the bond graph model of the PRSM.…”

Fatigue lifespan of a planetary roller-screw mechanism

“…(ii) It also gives the amount of rolling-to-sliding ratio in the mechanism. An approximate based on kinematic arguments only was proposed by Velinsky et al [3] and Ma et al [12]. In a different manner, Sandu et al [9] defined the optimal rolling ratio * , equation (13) for standard PRS mechanisms and equation (14) for inverted PRS mechanisms.…”

Investigation on the uncertain factors of the elastic–plastic contact characteristics of the planetary roller screw mechanism

“…Then, the sensitivity of the random variables is calculated. All the data points are scaled as follow expression (11) into [0, 1] for the purpose of comparing more fairly.…”

“…Those works were mainly focused on the structural design, 5 contact positions, 6 stiffness, and load distribution. [7][8][9][10] Besides, the researches on the analysis of the kinematics, 11,12 dynamics, 13 frictional heat, and thermal effects 14,15 also attract interests in these years. As some of the representative studies, Velinsky et al 16 studied the kinematics and efficiency of the PRSM and then provided a fundamental basis supporting various applications.…”