Hydraulic control device of working machine
AssigneeKobelco Construction Machinery Co., Ltd.
InventorTatsuya Takeshita
Life of this patent
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Abstract
A rotation prioritizing valve serving as a flow rate control valve of a hydraulic pilot type is provided on the meter-in side of an arm cylinder. At the time of a combined operation of arm pulling and rotation, the rotation prioritizing valve is activated by rotation pilot pressure so that a meter-in flow rate of the arm cylinder is throttled to prioritize rotation movement. On the premise of the above, a switching valve is provided in a pilot line of the rotation prioritizing valve and switched so as to release a throttling effect of the rotation prioritizing valve when boom lowering movement is added to the combined operation of arm pulling and rotation so that a rotation prioritizing function is cancelled.
Claims10
A hydraulic control device of working machine, comprising:
- hydraulic actuators including a rotation motor for rotation movement of an upper rotating body and an arm cylinder for arm pushing and pulling movement;
- a hydraulic pump serving as a hydraulic source;
- control valves for separately controlling an action of each of said hydraulic actuators;
- a rotation prioritizing valve, a rotation prioritizing function for prioritizing the rotation movement being executed by an effect of the rotation prioritizing valve at the time of a combined operation of arm pulling and rotation in which the rotation movement and the arm pulling movement are performed at the same time;
- and
- rotation priority restricting means adapted to restrict the rotation prioritizing function at the time of a specific combined operation in which movement of other hydraulic actuator is further added to the combined operation of arm pulling and rotation.
Dependencies are inferred from the claim text.