The emission quantity of goal

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic circuit of a construction machine having no risk of advancing in a bending shape, when a controller causes failure during straight-traveling.;SOLUTION: Pump control circuits 20 and 30 are provided with regulators 21 and 31 for controlling a delivery quantity of hydraulic pumps 11 and 12, horsepower reducing regulators 22 and 32 for reducing input horsepower, and a low flow rate priority selecting part. A horsepower reducing circuit 40 is arranged for connecting a first switching valve 41 and a second switching valve 42 in a cascade. A pilot pump 13 and an oil tank are connected to the primary side of the first switching valve 41, and output of the first switching valve 41 and the pilot pump 13 are connected to the primary side of the second switching valve 42, and output of respective solenoid valves 25 and 35 is connected to a control port of the first switching valve 41 and the second switching valve 42, and output of the second switching valve 42 is connected to horsepower reducing ports 22c and 32c of the respective horse power reducing regulators 22 and 32.;COPYRIGHT: (C)2010,JPO&INPIT