Spindle drive system of machine tool.

摘要

A spindle drive system of a machine tool, wherein a control mode changeover section of a control unit selects one of both a speed control mode for controlling a rotational speed of a spindle through negative feedback of the rotational speed of the spindle and a position control mode for controlling a rotational position of the spindle through negative feedback of the rotational position of the spindle, and a gain changeover section changes speed loop and position loop gains to a greater value during cutting operation than during non-cutting rapid feed operation when the position control mode has been selected.