SHOCKLESS MECHANISM IN HYDRAULIC CIRCUIT FOR EXCAVATING CONSTRUCTION MACHINE

摘要

PROBLEM TO BE SOLVED: To mitigate an operating shock in a boom or an arm or work attachment connected to a hydraulic circuit, by preventing rapidly rising of oil pressure in the hydraulic circuit of the boom or the arm or the work attachment. SOLUTION: A shockless hydraulic valve 1 is provided between a direction flow switching valve V1 of a hydraulic circuit in an excavating construction machine and a hydraulic cylinder 14 for turn operating a boom 41, arm 42 or work attachment 43 constituting an work arm 40 of the excavating construction machine. The shockless hydraulic valve 1 sets a pressure range cutting a peak pressure in the hydraulic circuit to a range including the lowest value of the peak pressure represented in the hydraulic circuit and the highest value of a steady pressure represented in the hydraulic circuit.