| 摘要 |
PROBLEM TO BE SOLVED: To improve accelerating/decelerating performance of a swing motor in swing regeneration, and to suppress lowering a regeneration amount.SOLUTION: A control system includes a regenerative motor 88 rotated by a working fluid conducted from a swing circuit 75 to drive a swing motor 76, a pressure detector 49 detecting a swing pressure or braking pressure of the swing motor 76, a swing regeneration switch valve 48 which opens when the pressure detected by the pressure detector 49 reaches a predetermined swing regeneration starting pressure to conduct the working fluid from the swing circuit 75 to the regenerative motor 88 to perform swing regeneration, relief valves 28, 29 which open when the swing pressure or braking pressure of the swing motor 76 reaches a set pressure, to permit the working fluid to flow to a low pressure side, and an adjuster 60 capable of adjusting set pressures of the relief valves 28, 29, and the adjuster 60 raises the set pressures of the relief valves 28, 29 from an initial set pressure when the pressure detected by the pressure detector 49 reaches the swing regeneration starting pressure. |
