| 摘要 |
A hydraulic line slit 20 formed in a valve body 50 of a flow distribution valve 5-1, a control chamber 70, and a hydraulic line 31-1 are connected to a signal transmitting hydraulic line 9. A lap portion 32 is formed in the hydraulic line slit 20, the lap portion 32 having a check valve function with a lap amount X when the valve body 50 is in a cutoff position. A 2-position, 3-way valve 11 is disposed in the hydraulic line 31-1. The valve 11 connects the control chamber 70 of the flow distribution valve 5-1 to only the signal transmitting hydraulic line 9 when an external signal F is not applied, and to both the signal transmitting hydraulic line 9 and a lower-pressure detecting hydraulic line 35, which is connected an outlet passage 5b of a flow distribution valve 5-2 on the side of a hydraulic actuator 3-2, when the external signal F is applied. With such an arrangement, during a combined operation including driving of an inertial body, a pressure on the lower load pressure side can be detected as a signal pressure without cutting off a load-pressure detecting hydraulic line on the higher load pressure side. Further, a portion for detecting a load pressure is simplified and the flow distributing function is not impaired.
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