HYDRAULIC CYLINDER APPARATUS FOR CONSTRUCTIONAL MACHINE PROVIDED WITH DAMAGE PROTECTION STRUCTURE OF CHECK VALVE

摘要

A hydraulic cylinder device for a constructional machine with a check valve damage prevention structure given in the present invention includes: a hollow cylinder which is placed at an angle from the ground; a rod which is installed to be able to slide inside the hollow cylinder; a piston which is fixed in the lower part of the rod, is in touch with the inner circumferential surface of the cylinder, and is able to slide; a head cover which is fixed in the lower part of the cylinder and has a passage to supply pressure oil from the outside to the piston; and a rod cover which is fixed in the upper part of the cylinder and has a penetration hole for the rod to appear; an oil recovery passage which penetrates through the piston in the longitudinal direction of the rod; and a check valve which is placed on the oil recovery passage and allows the oil to move only from the rod to the head cover. The device further includes a pipe member for preventing damage to the check valve one end of which is connected to the check valve in order to prevent foreign substances in the oil supplied from the rod to the check valve from flowing into the check valve, the other end of which is extended in the longitudinal direction of the rod, and which is accommodated inside the rod. The rod includes an accommodating groove unit which accommodates the upper part of the pipe member protruding above the top of the piston.