| 摘要 |
PURPOSE:To increase an amount of recovered energy, by a method wherein a pressure accumulator, a variable relief valve, and a check valve are coupled to the chamber on the bottom side of an auxiliary cylinder mounted in parallel to a boom cylinder. CONSTITUTION:An auxiliary cylinder 11 is situated in parallel to a boom cylinder 5, and a pressure accumulator 12, a variable relief valve 15, and a check valve 14 are coupled to a chamber 11a on the boom side of the auxiliary cylinder through a line 13. During an excavation work, a signal equivalent to the holding pressure of the boom cylinder 5 is guided to the variable relief valve 15, and since the set pressure of the valve 15 is automatically changed according to drop moment of a working machine, the efficiency of energy recovery is improved and it serves to save energy. |
