A New Study on the Parameter Relationships of Planetary Roller Screws

Abstract

As a more powerful transmission device, planetary roller screws (PRSs) recently have received more attention, compared to conventional ball screws. However, due to the complicated and unclear relationships among the PRS components’ parameters, it is difficult to design high-quality PRSs. To facilitate the PRS design, a new study on the parameter relationships of PRS is conducted in this work. New models of the axial stiffness and the frictional moment of PRS are developed, and the relationships of the axial stiffness and the frictional moment in terms of contact angle, helical angle, and tooth number of the roller thread are investigated. This study could contribute to the research of PRS to improve its transmission performance, especially to increase its positioning accuracy.

A Methodology of Designing the Teeth Conjugation in a Planetary Roller Screw

“…Based on the assumption that the rollers cooperate with the screw without slippage, the starts of the screw and the nut's threads are equal n s = n n [2]. An orbit, which includes the axes of the rollers, is concentric with respect to the screw and to the nut.…”

“…1. The rollers (2) cooperate with the screw (1) and the nut (3). The planetary gear transmissions consist of planetary gears (7) and ring gears (5).…”

“…The authors analysed the axial displacement of the roller cooperating with the screw according to the threads' parameters and also described the conditions of slip phenomenon. In the article [2], among other things, geometric parameters and kinematic relationships were analysed. Several authors studied also the load distribution between cooperating elements.…”

The specific dynamic capacity of a planetary roller screw with random deviations of a thread pitch

“…Several authors of previous publications related to the planetary roller screw considered models for determination of the load distribution. Ma et al (2012) adopted a model developed for ball screws given by Xuesong et al (2003) to determine the static load distribution. The rollers were assumed as rigid bodies and only contact deformations of threads were involved in calculations based on the Hertzian theory.…”

Self-stopping actuating mechanism with high coefficient of efficiency of the forward stroke for linear motion drives

“…These mechanisms have a high coefficient of efficiency in backand-forth stroke and the drives that use RSM to hold the load must have different automatic stopping mechanisms, which significantly increases the weight and the dimensions of the drive [6,11,12]. The application in such drives of self-stopping sliding screw-nut transmissions and worm gears with a forward stroke efficiency of <0.5 dramatically reduces the efficiency of the drive [5,6].…”