| 摘要 |
PROBLEM TO BE SOLVED: To prevent the lowering of a work holding force by a centrifugal force produced by the high speed rotation of a spindle and to prevent the lowering of the work holding force due to oil pressure leakage caused by the mutual communication of oil chambers in a chuck device. SOLUTION: In this chuck device 3, in fixing a work 2, oil pressure is generated in a first oil chamber by the advance and retreat movement of a piston member 41 of a hydraulic cylinder 11, the oil pressure is supplied to a second oil chamber 51 of a second hydraulic cylinder 12 via a check valve of a first oil passage 14 and a third oil chamber of a centrifugal cylinder pump 13. The holding force for the work 2 is generated in the second oil chamber 51 and the work 2 is held by a plurality of chuck claws 60, and during the rotation of the spindle 1, the lowering of the work 2 holding force is prevented by the centrifugal cylinder pump 13. In releasing the fixing of the work 2, oil pressures in the second oil chamber 51 and the third oil chamber 64 are forced to flow back to the first oil chamber 42 via a pilot check valve of a second oil passage.
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