PRESSURE OIL SUPPLY DEVICE

摘要

PURPOSE:To prevent swirl driving pressure from rapid variation at the time of simultaneously operating a boom and turn. CONSTITUTION:Discharged pressure oil of an oil pressure pump 20 is supplied to a boom cylinder 64 and a turning motor 65 via pressure compensatory valve 25 and a directional control valve 22 composed of a check valve part 23 and a reduction pressure valve part 24. Turning driving pressure can not be rapidly varied even at the time of turning acceleration and turning at a constant speed, by always making the opening area constant when the check valve part 23 in the pressure compensatory valve 25 on the side of the turning 65, in the case of simultaneous-operation.