PROBLEM TO BE SOLVED: To provide a construction machine hydraulic control device capable of reducing a meter-out pressure loss in response to a change in a negative load acting on a hydraulic actuator, and capable of preventing deterioration of operativity even when an abnormal state occurs to a pressure sensor detecting a magnitude of the negative load.SOLUTION: A construction machine hydraulic control device comprises: a meter-out channel in which a pressure oil discharged from a hydraulic actuator flows a variable throttle provided in the meter-out channel a load detector detecting a magnitude of a negative load that is a load applied to the hydraulic actuator by an external force and that is a load in the same direction of an operating direction of the hydraulic actuator and a control unit reducing, when an abnormality of the load detector is not detected, a total value of an opening area of the variable throttle in response to an increase in the magnitude of the negative load detected by the load detector and a manipulated variable of a manipulated variable detector, and reducing, when the abnormality of the load detector is detected, the total value of the opening area of the variable throttle to a value set in advance in response to the manipulation variable of the manipulation variable detector.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2017,JPO&INPIT【課題】油圧アクチュエータに作用する負の負荷の変化に応じてメータアウト圧力損失を低減でき、負の負荷の大きさを検出する圧力センサに異常状態が生じても、操作性の悪化を防止できる建設機械の油圧制御装置を提供する。【解決手段】油圧アクチュエータから排出される圧油が流れるメータアウト流路と、メータアウト流路に設けられた可変絞りと、外力により油圧アクチュエータに加えられる負荷であって、油圧アクチュエータの動作方向と同じ方向の負荷である負の負荷の大きさを検出する負荷検出器と、負荷検出器の異常を検出しないときには、可変絞りの開口面積の合計値を、負荷検出器により検出される負の負荷の大きさの増加と操作量検出器の操作量とに応じて低減し、負荷検出器の異常を検出したときには、可変絞りの開口面積の合計値を、操作量検出器の操作量に応じて予め定めた値まで低減する制御装置とを備える。【選択図】 図3
