| 摘要 |
PURPOSE:To correct the positioning error due to the advance of a feed screw by obtaining the correction value in accordance with the detected angle of the screw by an encoder and outputting said value into a servoamplifier and transmitting the differential pressure on the basis of the correction value supplied from a servovalve onto a thrust static-pressure bearing. CONSTITUTION:A correction-signal generator 17 reads-out the error registered in a memory from the signal supplied from a rotary encoder 15 and the distance signal supplied from a controler 16, and outputs said error as correction signal into a differential amplifier 18. Said amplifier 18 amplifies the output difference between the correction signal and a displacement meter 14, and said amplified value is further amplified in a servoamp 20 through a compensation circuit 19, and sent into a servovalve 21. Said valve 21 distributes the supplied pressure so that the control pressure is proportional to the error signal, and when the supplied pressures of static-pressure pockets 12 and 13 vary, a feed screw 5 shifts to the lower pressure side, and said displacement is detected by the displacement meter 14 and feedback-sent into the amplifier 18, and when the output of the displacement meter 14 becomes equal to the signal supplied from the signal generator 17, the feed screw 5 stops, and the correction of error is correctly performed. |
