先导流的较低的先导压力和用于控制，以便增加所述可变排量泵，控制器的倾斜角度的调节器，都多个用于控制喷墨显著流在所述致动器引起的从可变排量泵操作阀的 电磁阀被设定为打开位置以将可变排量泵的排出油供给到再生液压马达，并将先导流路切换电磁阀设定到关闭位置以使调节器 被减压阀减压。

The lower the pilot pressure in the pilot flow path provided with a regulator for controlling so as to increase the tilting angle of the variable displacement pump, and the controller, the variable displacement pump from both the plurality of operating valves for controlling the ejection significant flow being induced in the actuator regulator in the case where it is determined that the neutral position, and at the same time by setting the electromagnetic valve to an open position supplying the discharge oil of the variable displacement pump to the hydraulic motor for the regeneration, by setting the pilot flow channel switching solenoid valve to the closed position through the pilot flow path a pilot pressure that is guided to it by the pressure-reducing valve.