Development of High Speed Spindle for Machine Tool with Magnetic Bearings

Abstract

Most of spindles for machine tool are supported by ball bearings, and there are problems in the limits of high speed and high power as well as the cumbersome maintenance due to the short life time. In order to overcome these problems of the conventional spindles, the high speed spindle with magnetic bearings is developed in this study. Magnetic bearings for 60 000 r/min class high-speed spindle are designed, and high speed spindle with magnetic bearings are fabricated. Based on the running test up to 60 000 r/min, it is verified that the spindle is stably supported by the magnetic bearings, and the magnitude of the unbalance response at 60 000 r/min is less than 3 μm.

Design and Analysis of a Permanent Magnet Synchronous Motor Considering Axial Asymmetric Position of Rotor to Stator

“…To consider the maximum load on both bearings, we used the case where the direction of gravity to the rotor coincides with the direction of rotational force. The radial load was calculated by multiplying the sum of these two loads by a load factor of 1.2 (the value for the environment with little external impact on the shaft [19]). The load acting on each bearing was calculated using the moment equilibrium equation [19,20].…”

“…The radial load was calculated by multiplying the sum of these two loads by a load factor of 1.2 (the value for the environment with little external impact on the shaft [19]). The load acting on each bearing was calculated using the moment equilibrium equation [19,20]. We chose deep groove ball bearings in this study because they can carry both axial and radial loads and have outstanding noise and vibration characteristics.…”