| 摘要 |
PROBLEM TO BE SOLVED: To provide a preload mechanism for improving work machining position accuracy, wherein depending on the size of a carried load, a substantially optimal preload force is applied to each end part supporting bearing of an X/Y axis ball screw for carrying a plate material work such as an NC turret punch press. SOLUTION: In the outer end part of each end part supporting bearing 12 of each ball screw 6 made of a pair of ball bearings 12, a load cell 16 is provided for detecting axial displacement changed according to the size of a load on each ball screw 6. In addition, a preload mechanism P is provided, which is composed of a compression coil spring 19 having a specified spring constant, where preload force is changed corresponding to the outer value thereof, a ball screw shaft 18 for driving a motor 25, and a spring reception moving nut 20, and others.
|
