HYDRAULIC CIRCUIT, ENERGY RECOVERY DEVICE, AND HYDRAULIC CIRCUIT FOR WORK MACHINE

摘要

A hydraulic circuit that enables smooth absorption of the energy of a return fluid from a hydraulic actuator by means of an energy recovery motor. A return fluid passage to which the fluid discharged from a boom cylinder is branched is provided at the tank passage side of a solenoid valve of a boom control circuit. The return fluid passage comprises two return passages, which are provided with a flow rate ratio control valve for controlling a ratio of fluid that branches off into the return passages. The flow rate ratio control valve is comprised of a solenoid valve disposed in the return passage, which is provided with an energy recovery motor, and a solenoid valve disposed in the return passage, which branches off the upstream side of the solenoid valve.