SPINDLE UNIT OF MACHINE TOOL

摘要

A spindle unit of machine tool is provided with a pressure sensor (31) for detecting the pressing force of a rod (18) by a driver (25), a sensor (32) for detecting displacement of the rod (18), a section (33) for detecting the clamping force of a tool (19) by a collet (20) based on the pressing force of the rod (18) and the displacement of the rod (18), and a section (36) for judging the timing of replacing a disc spring (24) based on the clamping force of the tool and a preset urging force characteristic value of the disc spring (24) so that the timing of replacement is judged with high precision by detecting the clamping force of the tool properly.