TURNING HYDRAULIC CONTROL DEVICE FOR WORKING MACHINE

PROBLEM TO BE SOLVED: To improve control responsiveness in hydraulic control for reducing a relief loss in turning acceleration regarding a turning hydraulic control device for a working machine. SOLUTION: The working machine includes a hydraulic pump 1, a turning motor 2 and turning relief valves 3a, 3b. A turning operation amount P1related to the turning operation of the turning motor 2 is detected, and an operating fluid pressure P2supplied to the turning motor from the hydraulic pump 1 is detected. Based on the turning operation amount P1, the demand flow rate FRof an operating fluid demanded to the turning motor 1 is set. Further, a relief amount FEis estimated from the operating fluid pressure P2based on override characteristics of the turning relief valves 3a, 3b. The discharge flow rate of the hydraulic pump 1 is controlled based on a value obtained by subtracting the relief amount FEfrom the demand flow rate FR. COPYRIGHT: (C)2011,JPO&INPIT