| 摘要 |
PROBLEM TO BE SOLVED: To provide a counter balance valve enabling the saving of energy by reducing a pressure loss less than that of a conventional valve even if a flow rate is increased. SOLUTION: This counter balance valve 1 having a spool 11 is installed, together with check valves 3 and 3', between two supply/discharge passages 4 and 4' connecting hydraulic pumps P1 and P4 to a hydraulic motor 2. The spool comprises a center land 11a cutting off the two supply/discharge passages at a neutral position and side lands 11b and 11b'. The side lands 11b and 11b' are formed at intervals from the center land in the axial direction of the spool, and recessed parts 11c and 11c' allowing the inflow of an oil in the supply/discharge passage are formed between the side lands. Also, circular grooves 11d or chamfered parts 11e are formed on the anti-center land sides of the side lands. COPYRIGHT: (C)2006,JPO&NCIPI
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