| 摘要 |
A hydraulic circuit of a construction machine including center bypass passages, into which a pressurized oil discharged from hydraulic pumps is supplied, includes a directional control valve group including directional control valves that are arranged in tandem with the center bypass passages; a bleed-off valve arranged on a downstream side of each center bypass passage relative to the directional control valve group; and a merging circuit that merges the pressurized oil supplied into one center bypass passage and the pressurized oil in another center bypass passage, wherein each directional control valve includes a first internal passage that flows the pressurized oil supplied into the directional control valve out into the center bypass passages, and a second internal passage that supplies the pressurized oil supplied to the directional control valve to a hydraulic actuator of the construction machine, wherein the center bypass passages and the first internal passage form a parallel passage where the first internal passage flows the pressurized oil discharged from the hydraulic pump out onto downstream sides of the center bypass passages relative to the directional control valve, wherein the bleed-off valve performs a bleed-off control for the pressurized oil supplied through the parallel passage by changing an opening area of the bleed-off valve, wherein the merging circuit includes a merging directional control valve that controls an inflow direction of the pressurized oil to be merged. |
