Spindle apparatus.

摘要

A spindle apparatus for preventing a bending vibration of a rotary shaft. A magnetic bearing composite motor having a magnetic bearing function for controlling a position of a rotary shaft by magnetic forces and a motor function for imparting a rotational torque to the rotary shaft is provided between a front electromagnets and a rear electromagnet. A control circuit for controlling the magnetic bearing function of said magnetic bearing composite motor is commonly used with a control circuit for the magnetic bearing and is so constructed as to perform the function of the positional control only in the resonance frequency band. Accordingly, even if the rotary shaft is subjected to a bending vibration by using the position of the electromagnets as nodes of vibration, the bending vibration may be suppressed by the magnetic bearing function of the magnetic bearing composite motor located at a position of the middle portion of the vibration.