Work machine hydraulic system control method, work machine hydraulic system and work machine

摘要

To surely switch a hydraulic selector valve.SOLUTION: A control method of a hydraulic system of a working machine includes: a step for detecting switching of a direction selector valve 64 capable of changing a pilot pressure applied to a hydraulic selector valve 263 switchable to a plurality of switching positions according to the pilot pressure as a pressure of a pilot oil to a first position 64a having a prescribed opening, and a second position 64b having an opening larger than the prescribed opening corresponding to the first position; a step for detecting a rate of change of the pilot pressure; a step for determining whether the direction selector valve is held at the second position or not based on the rate of change of the pilot pressure; and a step for switching the direction selector valve from the second position to the first position when the rate of change is smaller than a predetermined determination value.SELECTED DRAWING: Figure 1