PURPOSE: To prevent the generation of peak pressure in a suction circuit by installing a means for accelerating the output of the valve opening and closing signals for a no-leak valve by a prescribed time by the output of the drive stop signal for a hydraulic pump in the case when the pressure of an accumulator is lowered to a set value.
CONSTITUTION: A pump stop control circuit 36 controls the drive of a hydraulic pump 21 by increasing and decreasing the pressure of an accumulator 26. A signal processing circuit 37 for outputting the drive signal supplied into the hydraulic pump 21 late by a prescribed time in comparison with the valve opening signal supplied to a no-leak valve 28 and the valve closing signal early in the case when the pressure of the accumulator 26 for high pressure is lowered to a set value. Therefore, the generation of peak pressure in the suction circuit, accompanied with the delay of the opening operation of the no-leak valve, is prevented.
HASHIMOTO KOJI
OINUMA YOICHI
YONEKUBO YOSHITAKE
