| 摘要 |
PROBLEM TO BE SOLVED: To provide a collet chuck capable of highly accurately processing by restraining deformation of a workpiece by grasping by uniform grasping force, even in the thin annular ring-shaped workpiece nonuniform in an inner peripheral surface. SOLUTION: A draw bar is constituted of a first draw bar 3a sliding in a through-hole 7 arranged in a chuck body 2 and a second draw bar 3b sliding in a through-hole 13 arranged in the first draw bar 3a, and respective sliding contact parts A and B between tapered surfaces 15a and 15b of the respective draw bars and a tapered surface 25 of a collet 4 and a workpiece gripping part 24 are respectively dividedly limited to a local range of the circumference. While setting a clearance Sa between a sliding shaft part 12a of the first draw bar 3a and the through-hole 7 as a minimum clearance capable of sliding the first draw bar 3a, a clearance Sb between a sliding shaft part 12b of the second draw bar 3b and the through-hole 13 is set as a clearance larger than a nonuniform quantity of a workpiece inner peripheral surface, and the respective draw bars 3a and 3b are respectively independently operated. COPYRIGHT: (C)2011,JPO&INPIT |
