| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hydraulic drive device for a hydraulic working machine, which allows a second internal regeneration oil passage to be provided also in a second directional control valve for controlling a hydraulic actuator different from a hydraulic cylinder controlled by a first directional control valve provided with a first internal regeneration oil passage, in securing a high regeneration flow rate. <P>SOLUTION: A first internal regeneration oil passage 31 is provided in a spool in a boom direction control valve 30 so as not to pass through both ends of the spool, and a second internal regeneration oil passage 63 is provided in a spool in a second-arm direction control valve 50 so as not to pass through both ends of the spool. The first boom direction control valve 30 is provided with: a first connection oil passage which connects the first internal regeneration oil passage 31 and an oil passage 141, and a second connection oil passage which connects the first internal regeneration oil passage 31 and an oil passage 151. The second-arm direction control valve 50 is provided with a third connection oil passage which continuously connects the second internal regeneration oil passage 63 and the oil passage 141, and a fourth connection oil passage which continuously connects the second internal regeneration oil passage 63 and the oil passage 151. <P>COPYRIGHT: (C)2012,JPO&INPIT |
