| 摘要 |
PURPOSE:To effectively utilize the power of a prime mover by controlling connections of the plural number of pressure control valves to excessive oil lines and also to each discharge line of pump. CONSTITUTION:A discharge port of the third variable pump 21 is connected to a pressurized oil supply port 25a of the first control valve 25 through the third discharge line 27, and the pressurized oil is preferentially supplied to a turning motor 9 among the third actuator group through an auxiliary turning selector valve 17. Further, an excessive flow port 25c is connected to a pressurized oil supply port 26a of the second pressure control valve 26, a preferential port 26b of which is connected to a main and selector valve 18 and supplies excessive oil to an arm cylinder 5. The second excessive flow line 29 is connected to the first discharge line 23 and the second discharge line 24. |
