HOLDING VALVE OF HYDRAULIC SYSTEM FOR CONTROLLING WORK DEVICE OF EXCAVATOR AND HYDRAULIC SYSTEM FOR CONTROLLING WORK DEVICE OF EXCAVATOR WITH THE SAME

摘要

According to the present invention, the main poppet that moves to open and close the valve-side connector connected to the control valve side; A piston unit positioned opposite the valve-side connector with the main poppet interposed therebetween and movable toward the main poppet by a pilot pressure applied to a control valve; A poppet sheet member positioned between the main poppet and the piston unit and spaced apart from the main poppet to form a back pressure chamber communicating with the hydraulic cylinder side between the main poppet and the main poppet; A first pilot poppet disposed in the back pressure chamber and seated on the poppet sheet member; And a second pilot poppet disposed in the back pressure chamber and seated on the first pilot poppet, wherein the poppet sheet member has a through hole in communication with the back pressure chamber and blocked by the sheet of the first pilot poppet. 1 In the pilot poppet, a passage hole is formed in which the back pressure chamber and the through hole are communicated, and the second pilot poppet is sheeted, and an end of the second pilot poppet is greater than the end of the first pilot poppet in the through hole. A holding valve of a hydraulic system for controlling an excavator working device is provided, which is formed to protrude, and the piston unit pushes while sequentially in contact with the end of the second pilot poppet and the end of the first pilot poppet as it moves toward the main poppet. .