| 摘要 |
PROBLEM TO BE SOLVED: To provide a chuck opening/closing device for a numerically controlled lathe, for opening/closing a chuck by driving a servo motor, while holding the workpiece gripping force of a chuck pawl constant even when a spindle is rotated. SOLUTION: When the spindle 2 is rotated, the rotating speed of the spindle 2 is detected and the position of the chuck pawl 4 is detected, centrifugal force to be received by the chuck pawl 4 is calculated in accordance with the detection results, and the rotation of the servo motor 12 is controlled to apply force resisting to the centrifugal force to the workpiece gripping force of the chuck pawl 4. Thus, even if the chuck pawl 4 receives the centrifugal force when the spindle 2 is rotated, the set workpiece gripping force is held constant without being changed. COPYRIGHT: (C)2009,JPO&INPIT
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