| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of a conventional hydraulic circuit for small- sized excavating revolving working vehicle, or a poor efficiency in the drive of a boom, arm, bucket or the like that is a working machine by a hydraulic actuator by use of two hydraulic pumps. SOLUTION: In this hydraulic circuit for driving the actuator for driving a boom 6, a bucket 4, a revolving superstructure 8, an arm 5, a blade 10 and lateral traveling devices 1 by the two hydraulic pumps P1 and P2, directional selector valves 50R and 50L for lateral traveling motors are arranged on the upstream side from directional control valves for boom, bucket, revolving superstructure, arm and blade 51, 52, 54, 55, and 53, and a parallel oil passage 33 is branched from a feed oil passage communicating with each hydraulic pump. Check valves 40 and 41 are interposed in the rear of the positions branched to the inlet sides of the lateral traveling motor directional selector valves of the parallel oil passage to form a combined oil passage 33c from both the hydraulic pumps. The combined oil passages are connected to the primary side of each directional selector valve for boom, bucket, revolving superstructure, arm and blade through throttle valves, respectively.
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