| 摘要 |
<p>A control system employed in a machine tool of the type in which a gear mechanism 9 disposed between the spindle 7 and spindle motor 4 transmits the rotational motion of the motor 4 to the spindle 7, the system enabling the spindle 7 to be brought to a stop at a predetermined rotational position in a shorter period of time when the gear mechanism 9 is set in low gear, that is, while the rotational speed of the motor 4 is being reduced by the gear mechanism 9 as it is being transferred to the spindle 7. This permits the spindle 7 to be stopped at the predetermined position in the same amount of time which is required when no reduction in speed takes place between the motor 4 and spindle 7. When the spindle 7 arrives at a region where it is to be controlled in order to stop at the predetermined rotational position, the arrangement is such that a position deviation signal for guiding the spindle to said position is applied as an input signal to a speed control loop for controlling spindle rotation, the position deviation signal being variable in accordance with the gear ratio of the spindle gear mechanism 9. Positioning gain, which is obtained by dividing the speed of the spindle motor 4 by an amount of spindle motor rotation that depends upon the position deviation of the spindle 7; is so controlled as to remain constant regardless of the speed change ratio between the spindle 7 and spindle motor 4 as determined by the gear mechanism 9. </p> |
