METHOD OF MEASURING SYNCHRONIZATION ACCURACY OF SYNCHRONOUSLY ROTATING ROTARY SHAFT OF NC MACHINE TOOL

摘要

PURPOSE:To measure the accuracy of synchronization of the rotation of two shafts simply and accurately, by converting outputs into the pulses of the same frequency by means of frequency dividers and inputting the difference in phase between these pulses into a rotation accuracy measuring instrument. CONSTITUTION:Optical encoders 61, 62 are installed in motors for driving a hob spindle and a table shaft. Feedback signals outputted from the encoders 61, 62 are inputted into a frequency dividers 7, 8 so as to make the frequencies of pulses of these signals agree. After being amplified by differential amplifiers 9, 10, these signals are converted into a phase difference pulse signal C of the both pulse signals by means of a phase difference signal generator 11. A clock pulse generated by a crystal oscillator 12 is counted by an arithmetic unit 13, which also operates its reciprocal. The product of the operated result with the time of the phase difference is calculated by an arithmetic unit 14 and stored in a memory 15. This result is converted into an analog value by means of a D-A convertor, with the resultant output being proportionate to the phase difference between the rotation of a hob spindle and the rotation of a table shaft.