| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic circuit device easily adaptable for two-speed control when necessary by option or the like. SOLUTION: The hydraulic circuit device includes a pair of main circuit systems having a plurality of control valves 2-5, 8-11, a pair of main pumps MP1, MP2 individually connected to the main circuit systems, a sub circuit system different from the pair of main circuit systems, a sub pump SP connected to the sub circuit system, and a joint control valve 14 connected to the sub pump. A control valve 11 for controlling a bucket cylinder C is linked with the joint control valve 14. When the control valve 11 is changed over, the joint control valve 14 is also changed over in linkage therewith to join discharge oil from the sub pump SP to the most upstream side of the main circuit systems. COPYRIGHT: (C)2011,JPO&INPIT |
