| 摘要 |
PURPOSE: A hydraulic circuit of construction equipment is provided to reduce consumption of energy. CONSTITUTION: In a hydraulic circuit of construction equipment, a directional selecting valve(4) feeding hydraulic oil to an actuator is installed to an unload passage(3) communicating with a pump(1). The directional selecting valve has a communicating port connected to the unload passage; a pump port(P) branching off from the upper stream side of the unload passage; a tank port(T) communicating with a tank(2); and two actuator ports(A,B) communicating with the actuator. The directional selecting valve has a neutral position(4a) for connecting the communicating port and shutting off the actuator ports, and conversion positions(4b,4c) for connecting the pump port with one of the actuator ports and connecting the other of the actuator ports with the tank port while tightening the communicating port. A flow reduction unit(6) is installed to the downstream side of the unload passage of the directional selecting valve. The flow reduction unit reduces a flow if the pressure of a downstream-side unload passage(3a) is under a predetermined value when the directional selecting valve is positioned at the conversion position.
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