HYDRAULIC CIRCUIT OF CONSTRUCTION MACHINE

摘要

PROBLEM TO BE SOLVED: To suppress the amount of pilot oil leaked from a throttle path while assuring damping action at sudden operation.

SOLUTION: A throttle path 16 for returning part of pilot oil to a tank is formed by a tank path 19 provided in a valve block 17 of a control valve 3 and a notch 20 provided in a spool 18 thereof. The throttle path 16 is opened within a section from a vicinity of a stroke where a hydraulic actuator starts to move to right before a stroke end among a spool stroke of the control valve 3. An opening area of the path 16 is slowly reduced in accordance with an increase in the stroke at a final phase of the section.

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