Analysis of ballscrew stiffness owing to contact deformation in leadscrew systems

Abstract

Positioning error of ballscrew driven feeddrives depends upon stiffness of leadscrew systems. Total axial stiffness of the leadscrew system consists of stiffnesses of the nut, the screw shaft, the support bearings, and the nut bracket. The nut stiffness depends upon screw characteristics, preload and operating conditions. This should be thoroughly studied according to the contact deformation between balls and grooves. In this paper, ballscrew nut stiffness due to contact deformation between balls and grooves according to the preload and operating conditions is studied. Positioning accuracy estimation method is also proposed.