| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic driving system of a construction machine capable of reducing pump power for revolving in revolving deceleration.SOLUTION: A hydraulic driving system of a construction machine includes a variable displacement type pump of which a tilting angle is changeable, a pair of revolving supply lines connecting a revolving control valve and a revolving motor, a pair of electromagnetic relief valves disposed in directions opposite to each other in a cross-linking passage connecting the pair of revolving supply lines to each other, and a control device controlling the pair of electromagnetic relief valves so that a relief pressure is kept at a reference pressure at a time excluding a revolving deceleration time, and a relief pressure of the electromagnetic relief valves for making a hydraulic oil escape from the revolving supply line at a discharge side is significantly lowered from the reference pressure as a revolving signal output from a revolving operation valve is increased in the revolving deceleration. The revolving control valve is constituted to be moved according to the revolving signal at the time excluding the revolving deceleration time, and returned to a neutral position at the revolving deceleration time.SELECTED DRAWING: Figure 1 |
