NON-CONTACT BEARING SPINDLE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a non-contact bearing spindle device capable of preventing cutting errors by avoiding the conditions of resonance prior to machining. SOLUTION: A main spindle 4 is supported by static pressure and magnetic compound bearings 6 and 7. A signal processing means 32 is provided for analyzing the frequency of an output signal of a displacement detecting means 28 which detects the displacement of the main spindle 4. A natural frequency detecting means 34 is provided for determining the natural frequency of the main spindle 4 during mounting of a tool, based on the result of the frequency analysis by the signal processing means 32. A means 36 for treating at the time of a coincidence on the number of revolutions and the number of tool blades is provided which performs a predetermined process in case that an integer times of a formula; (the number of revolutions)×(the number of tool blades) coincide with the natural frequency with the result of detection by the natural frequency detecting means 34 indicates.