AN APPARATUS FOR PREVENTING THE ECCENTRICITY OF A MAIN SHAFT OF TAIL STOCK

摘要

PURPOSE: An eccentricity preventing device is provided to obtain high degree of precision by preventing eccentricity of a headstock of a tailstock through uniform supply of a fluid to a fluid inlet ring when one end of a long workpiece is held in the tailstock. CONSTITUTION: For holding one end of a workpiece in a tailstock of a CNC machine, a frame(1) is moved close to the workpiece on a bed and a fluid is supplied via a fluid line. The fluid is supplied onto a piston(22a) along a fluid supply hole(22d) of a cover(22c), and a hollow core shaft(2) is advanced by the flow pressure of the fluid. Then, a tailstock center(21) installed in front of the hollow core shaft holds one end of the workpiece. As the fluid is supplied to a fluid inlet port through a hydraulic line connected with a fluid inlet ring(13), the fluid inlet ring formed of a thin sheet is expanded and the outer face of the hollow core shaft is pressurized. Therefore, eccentricity of the hollow core shaft is prevented.