HYDRAULIC CIRCUIT FOR WORKING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic circuit suited for use in a working machine with a slewing motor and a working arm cylinder independently driven, which can secure a suitable amount of bucket lift in interlocking motion to stabilize truck loading operation and enables quick slewing when solely performing slewing motion.

SOLUTION: A second hydraulic supply means 23 for supplying pressure oil to a slewing mechanism for slewing an upper slewing body is provided separately from first hydraulic supply means 21, 22 for driving an arm mechanism. A control means 50 for controlling output of the second hydraulic supply means performs control that the output of the second hydraulic supply means 23 takes a predetermined, fixed value when the slewing mechanism 40 is solely driven and that the output of the second hydraulic supply means 23 gradually increases to the fixed value according to an elapsed time from the beginning of interlocking when the slewing mechanism 40 and the arm mechanism are interlocked and driven.

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