| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress cavitation in a meter-in flow fluid passage and hunting of the rotation speed of a hydraulic actuator and to suppress the change in speed of a hydraulic actuator according to the weight of load. <P>SOLUTION: The hydraulic control apparatus includes: a meter-in flow control device 62 which controls the flow rate of the meter-in fluid passage 30; a meter-out orifice 71 disposed at a meter-out fluid passage 40; a meter-out flow control device 72 which controls the flow rate of the meter-out fluid passage 40 to keep the inlet-outlet pressure difference of the meter-out orifice 71 constant; a back pressure valve 81 for generating a set back pressure Pbk at an upstream side position; and a regeneration fluid passage 50 branched from the meter-out fluid passage 40 at a position upstream of the back pressure valve 81 and merged with the meter-in fluid passage 30. A meter-out flow rate Qmo controlled by the meter-out flow control device 72 is controlled so as to make the meter-out flow rate Qmo be greater than the meter-in flow rate Qmi controlled by the meter-in flow control device 62. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
