| 摘要 |
PROBLEM TO BE SOLVED: To regenerate hydraulic energy which becomes excessive when an actuator for neither a boom cylinder nor a swing motor is in operation.SOLUTION: A control system of a hybrid construction machine includes a regenerative passage changeover valve 58 which can open and close a passage 56 of a circuit system S2 and a high-pressure selecting changeover valve 71 which supplies hydraulic oil from a sub-pump SP to passages 55, 56, and the regeneration passage changeover valve 58 has a normal position for cutting off the hydraulic oil and a regenerative position for allowing the hydraulic oil to flow from a neutral flow passage 18 to a regenerative motor M when the working hydraulic pressure of the neutral flow passage 18 reaches set pressure during the operation of an actuator. The high-pressure selecting changeover valve 71 has a normal position for proportionally dividing the hydraulic oil of an assist passage 68 to the passages 55, 56, a first changeover position for supplying the hydraulic oil of the assist passage 68 more to a neutral flow passage 6 when the working hydraulic pressure of the neutral flow passage 6 is high, and a second changeover position for supplying the hydraulic oil of the assist passage 68 more to the neutral flow passage 18 when the working hydraulic pressure of the neutral flow passage 18 is high. |
