Foundational development, modeling and configuration of state stabilizing mechanism to maintain axial tension in ball screw feed drive systems

Abstract

This study presents a state stabilizing mechanism that can maintain consistent axial tension in the ball screw feed drive systems used within machine tools, even when the screw shaft is elongated due to thermal expansion. The proposed mechanism is structured as an attachable unit for the end of the screw shaft in a feed drive. During a machining cycle, the heat generated from the rotation of bearings within the unit is then used as an intrinsic energy source to expand hydraulic fluid sealed within a pressurized chamber. By minimizing the variation in pressure within the chamber, the mechanism autonomously maintains stable axial tension in the feed drive. After modeling pressure within the chamber and comparing calculated results with trends in actual test data, the proposed mechanism was confirmed to maintain stable axial tension even in the presence of shaft elongation. Results in preliminary tests validate the mechanism as a solution that may be considered during the design stage.