| 摘要 |
PROBLEM TO BE SOLVED: To enable surplus energy of a revolving motor to be efficiently utilized for a hydraulic motor.SOLUTION: A hydraulic control circuit of a construction machine includes a revolving motor RM, a hydraulic pump P being a pressure source of this revolving motor RM, and an operation valve 1 arranged between the revolving motor and the hydraulic pump, having the upstream side connected to the hydraulic pump or a tank and having the downstream side connected to the revolving motor. The upstream side of a variable throttle valve 7 of a circuit pressure control device S described in claim 1, is connected to connecting passages 3 and 4 for connecting the operation valve 1 and the revolving motor RM, and the downstream side of a relief valve 8 is connected to a supply passage 15 connected to a hydraulic motor M for rotating a generator G. |
