| 摘要 |
PURPOSE:To sufficiently utilize the effective power of an engine by allowing a cut-off valve to be switched when a pump is cut-off, and supplying the output cut-off by the pump, for the output of another pump. CONSTITUTION:When the discharge pressure of the second variable capacity type hydraulic pump 2 increases, and the second cut-off valve 25 is switched to the left position shown on the figure, the second servo-piston 25 shifts leftward on the figure, and the pressurized oil in the second oil-pressure source 27 is introduced into the chamber 35 of the first cylinder 5 through the second cut- off valve 25 and a pilot line 35. Therefore, the first set piston 6 of the first cylinder 5 is shifted leftward on the figure, and the first pilot servo-valve 4 is switched. Therefore, pressurized oil is supplied into the first servo-piston 11, and the discharge amount of the first variable-capacity type hydraulic pump 1 is determined. Therefore, when a pump is cut-off, the cut-off portion of the output can be supplied as the output of other pumps, and the effective power of an engine can be utilized efficiently. |
