HYDRAULIC CIRCUIT FOR CONSTRUCTION MACHINE, AND PRESSURE REDUCING VALVE IN USE FOR THE SAME

摘要

<P>PROBLEM TO BE SOLVED: To prevent a stopping delay of a hydraulic cylinder caused by a restoring delay of the spool of a pressure reducing valve when restored into a neutral state from the elongating operation of the hydraulic cylinder. Ž<P>SOLUTION: In the hydraulic circuit, the pressure reducing valve 11 is held between a second pilot oil path 75c connecting a secondary side port 78b of the pressure reducing valve 11 to one pilot port 73a and a first pilot oil path 75a connecting a primary side port 78a of the pressure reducing valve 11 to the output port of one remote control valve 90, parallel branch oil paths 11c are provided in the pressure reducing valve 11, and a check valve 12 is mounted between the parallel branch oil paths 11c in such a direction that pilot pressure oil flows from the pilot port 73a to the output port of the remote control valve 90. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž