| 摘要 |
PROBLEM TO BE SOLVED: To optimally restrict a drive speed of a hydraulic actuator (a hydraulic motor for slewing motion) in cargo suspension work. SOLUTION: In this hydraulic circuit for slewing a crane, a solenoid proportional pressure reducing valve 7 is provided between pilot valves 6A, 6B operated by a pilot pump 4 and an operation lever 5, and a pressure reducing characteristic of the pressure reducing valve 7 is controlled such that a secondary pressure P2 by the pressure reducing valve 7 is reduced as a working moment m increases. Thereby, the secondary pressure P2 is regulated according to the working moment m to restrict a maximum slewing speed of a revolving superstructure 63.
|
