| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic control device for construction machinery, which can reduce a load imposed on a drive unit of a hydraulic pump of an engine etc., when a vehicle body is turned at a slow speed. SOLUTION: A power shovel vehicle includes a revolving superstructure which is revolvably provided, and a turning motor 19 which drives the revolving superstructure in a revolving manner. The hydraulic control device 18 of the power shovel vehicle includes: the first and second hydraulic pumps P1 and P2 for feeding hydraulic oil; a first hydraulic actuator which is driven by the hydraulic oil discharged from the first hydraulic pump P1; a second hydraulic actuator which includes the turning motor 19 driven by the hydraulic oil discharged from the second hydraulic pump P2; a channel control valve 50 which can open/close a channel for establishing communication between a main channel 20 for connecting the first hydraulic pump and the first hydraulic actuator together, and a sub-channel 30 for connecting the second hydraulic pump P2 and the second hydraulic actuator together; and a low-speed turning switch 54 for operating the opening/closing of the channel of the channel control valve 50. COPYRIGHT: (C)2011,JPO&INPIT
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