THERMAL DISPLACEMENT CORRECTING DEVICE OF MAIN SPINDLE IN VERTICAL MACHINING CENTER

摘要

PURPOSE:To automatically correct thermal displacement, by providing a displacement detector in a spindle head and performing feedback of an output signal of the detector as shifting quantity of the original point of an NC device. CONSTITUTION:The relative displacement to a direction Y is detected between a magnetism generating material 8, mounted to the point end of a quartz glass bar 7 fixed to the surface of column sliding guide parts in a main spindle head 4 through a supporter 6, and a detecting head 9, fixed to a main spindle bearing cover 10 through a bracket 11. This relative displacement is amplified, shaped by a detector circuit 12, converted into a digital signal in an AD converter 13, and fed to an NC device 14 as shifting quantity of the original point for the axis Y to move a column 3 to the Y-direction and correct the thermal displacement. The thermal displacement of a main spindle can be automatically corrected exactly and easily by utilizing a small amount of thermal expansion of the quartz glass.