| 摘要 |
<p>PROBLEM TO BE SOLVED: To select the set pressure of an upstream actuator circuit, without using an external solenoid selector valve. SOLUTION: A relief valve 15 provided for an outrigger circuit A of an upstream actuator circuit having a lower maximum set pressure. is constituted as a variable set pressure relief valve in which set pressure may be varied corresponding to a pilot pressure. The valve 15 is fed the pressure in a working actuator circuit B of a downstream actuator circuit having a higher maximum set pressure through a pilot line 19 as the pilot pressure to rise the set pressure.</p> |
