| 摘要 |
<P>PROBLEM TO BE SOLVED: To allow a hydraulic actuator to operate with good response while reducing power consumption. <P>SOLUTION: A machine tool has: a cross rail 6; a W axis servo motor 24 that drives the cross rail 6 for operation; a balance cylinder 27 that supports the cross rail 6 and operates according to the operation of the cross rail 6; a hydraulic circuit 28 that includes a pump 30 and an electronic pump motor 32 which drives the pump 30; a storage means that stores an NC program for controlling the operation of the W axis servo motor 24; a rotation speed calculating section that reads the content of the NC program, calculates required amount of working oil to be supplied to the balance cylinder 27 according to a driving state of the cross rail 6 by the W axis servo motor 24, and determines the number of rotations of the pump corresponding to the amount of oil to be supplied; and a pump motor rotation speed controlling section including an inverter or the like. The pump motor rotation speed controlling section changes the number of rotations of the pump motor 32 based on the number of rotations determined by the rotation speed calculating section. <P>COPYRIGHT: (C)2012,JPO&INPIT |
