Patent ID: 9725884
Date: 2017-08-08
CPC Classifications: E02F,F15B

Claim:
1. A hydraulic circuit of a construction machine including a plurality of center bypass passages, into which a pressurized oil discharged from a plurality of hydraulic pumps is supplied, the hydraulic circuit comprising: a directional control valve group including a plurality of 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 wherein each directional control valve includes wherein the center bypass passage 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 passage 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 is arranged on an upstream side of the bleed-off valve and controls an inflow direction of the pressurized oil