| 摘要 |
PROBLEM TO BE SOLVED: To achieve favorable operability by restraining a speed change in turn by preferentially supplying a pressurized oil to a swivel motor even if a saturated condition arises when the swivel motor and other actuator are simultaneously operated and by restraining a shock at the start of turn even in turn-only operation. SOLUTION: In a hydraulic driving device, a flow control valve 6a for turn comprises a fixed restriction 20 setting a maximum demand flow rate for turn and an open center type directional control valve 40, an output pressure identical to an output pressure introduced from an engine speed detecting valve 13 to a pump tilting control part 17a as a target differential pressure for LS control is introduced to a pressure compensation valve 7a, a target compensated differential pressure is set therefor, and other pressure compensation valves 7b, 7c, ... are set by a differential pressure between a pump discharge pressure which is an output pressure from a detecting valve 11 and the highest load pressure. Shuttle valve 9a, ... detects a pressure between the fixed restriction 20 and the directional control valve 40 as a load pressure of the swivel motor 3a. COPYRIGHT: (C)2011,JPO&INPIT
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