| 摘要 |
PURPOSE:To provide an effective utilization of all discharged hydraulic oil from the pump by a method wherein a flow rate of a hydraulic actuator connected to an output port of a flow dividing valve is combined with other output port to make a normal operation of the flow dividing valve when the actuator shows a stroke end. CONSTITUTION:A return oil passage (c) in the rolling controlling hydraulic circuit A is connected to a hydraulic oil feeding passage (d) in the lift arm hydraulic circuit B. Hydraulic cylinder 5 has in a piston a valve for communicating the piston chamber with the piston rod chamber when the cylinder shows a stroke end. Thus, if even after the hydraulic cylinder 5 reaches its stroke end and stops there, the rolling control for the direction of stroke end movement is performed, the hydraulic oil from the control port (a) in the flow priority valve 10 is passed through the hydraulic cylinder 5, flowed into the return passage (c) and then combined with a hydraulic oil from the surplus port (b) in the hydraulic circuit B. Since a hydraulic oil is always flowed out from the control port (a), the flowing-out of the hydraulic oil from the surplus port (b) may be kept. |
