| 摘要 |
A liquid-pressure control device 1 includes a switching valve 26, a manipulation valve 36, a first back pressure output mechanism 42, and a second shuttle valve 41. When a manipulation lever 37 is manipulated, the manipulation valve 36 outputs a first output pressure P01 corresponding to a manipulation amount of the manipulation lever 37. When a predetermined operation state is satisfied, the first back pressure output mechanism 42 outputs a first back pressure pb1. The first output pressure P01 its input as a first pilot pressure P1 to the switching valve 26, and the first back pressure pb1 is input as a second pilot pressure P2 to the switching valve 26. The switching valve 26 supplies a liquid pressure to a boom cylinder 7 at a flow rate corresponding to a differential pressure between the first and second pilot pressures P1 and P2. |
