DYNAMIC STIFFNESS MODEL OF PLANETARY ROLLER SCREW MECHANISM WITH CLEARANCE, GEOMETRY ERRORS AND ROLLING-SLIDING FRICTION

摘要

This paper applies the bond graph theory to construct a dynamic stiffness calculation model for the planetary roller screw mechanism with factors such as structural stiffness and contact stiffness of screw, clearances, geometry errors, rolling-sliding friction, and load distributions on the roller threads and a group of rollers under two installation modes. In addition to predicting how dynamic stiffness varies with the load frequency and load amplitude under two installation modes, how does it change with the structural parameters such as screw diameter, helix angle, contact angle and number of roller threads under two installation modes are also investigated. The results can provide theoretical basis for the design of planetary roller screw mechanism considering dynamic stiffness with the influences of clearances, geometry errors, friction and installation modes.