| 摘要 |
PROBLEM TO BE SOLVED: To improve fuel safe performance in lowering a load.SOLUTION: A control system of a hybrid construction machine includes: first and second main pumps MP1, MP2; a boom cylinder BC raising a boom by supplying a hydraulic oil to a piston-side chamber 25, and lowering the boom by discharging the hydraulic oil from the piston-side chamber 25; a regenerative control spool valve 26 controlled by a pressure of a pilot pressure oil and adjusting a flow rate of the hydraulic oil discharged from the piston-side chamber 25; a regenerative motor M for regeneration, rotated by the hydraulic oil discharged from the piston-side chamber 25: an electrical rotating machine 35 connected to the regenerative motor M; and a switch valve 60 for fail-safe, switching a pressure of a regeneration passage 27a between the regenerative control spool valve 26 and the regenerative motor M as a pilot pressure, and lowering a pressure of the pilot pressure oil to the regenerative control spool valve 26 to throttle the flow rate of the hydraulic oil discharged from the piston-side chamber 25, when the pressure of the regeneration passage 27a is less than a set pressure. |
