No abstract

Angular contact bearings are the most popular type of bearings used in the motorized high speed spindle. An initial preload and operating-induced load control are managed to ensure its rigidity, but the centrifugal force and temperature will rise with the rapid increase of spindle speed. Although the centrifugal force and thermo induced bearings load are applied on the spindle assembly. This paper aims to study innovative structure solution of spindle and develop a new type of super precision bearings which will ensure the lifetime and high performance of spindle. Section II proposed an improved inverter output filter, for pulsewidth modulated (PWM) drive system. The proposed filter is shown to effectively reduce the power losses in the spindle. This usage of the filter can improve lifetime of bearings and gain a higher output power of the spindle. The simulations show a 20 KW, 400 Hz PWM drive system with total loss reduced 13.36%, and a 20KW, 800HZ PWM drive system with total loss reduced 15.77%. Therefore, the filter configuration is an excellent contribution for PWM drive system.

No abstract

A dual displacement measurement meter applied as a compensatory device for spindle thermal growth compensation , it can reduce the measurement error dramatically from single measurement device. The result matches the laser inspection report, which is an external direct checking device and been considered as one of the best checking device of spindle thermal growth. However, the non-flat surface of spindle nose, fluctuating measurement distance and the tiny measurement meter can hardly be fitted rectangular to spindle nose surface which create a certain percentage of error when the single displacement measurement meter is applied.The addition of a differential amplifier will greatly enhance the linear output voltage fed back from dual measurement meter to the CPU and provide a high sensitive level of compensation. This new device can reduce the measurement error from 6% down to 1.8%. The machining tolerance can be improved greatly and machining time is reduced. The quality of the machine and the cutting performance can be upgraded.