| 摘要 |
PURPOSE:To enable control of preload during operation, in a ball screw feed mechanism where a preload spacer is placed between a pair of nuts mounted axially over the threaded shaft of ball screw, by employing such spacer as controllable of deformation externally. CONSTITUTION:In a ball screw feed mechanism to be employed for table feeding of machine tool, a pair of splitted nuts 5, 5' are fitted at the outside of ball screw shaft 1 while a plurality of balls 7... are provided circulatably between spiral screw grooves 6, 6' at the inside of nuts 5, 5' and spiral screw grooves 2, 2' of ball screw shaft 1. Here, an electric distortion element 11' is employed as a spacer to be placed between the facing surfaces of nuts 5, 5'. Said element 11 is displacable axially in proportion to the input voltage to be applied externally through a lead wire (not shown) thus to apply preload between the ball 7 and the screw grooves 6, 6', 2, 2'. |
