HYDRAULIC CONTROL VALVE Russian patent published in 1999 - IPC

FIELD: applicable in hydraulic systems of various machines, for example, in hydraulic systems of construction manipulators. SUBSTANCE: the hydraulic control valve has a number of working sections 1 with pressure (2) and drain (3) feed lines, working discharge lines 4, pressure (5) and drain (6) lines passing through the working sections and connected parallel to the respective pressure and drain feed lines, and loading line 7, as well as unloading throttling- valve 8 and pressure-controlled normally- closed valve 9 with control feed line 10 connected to loading line 7; the valve inlet is connected to the pressure line, and the valve outlet - to the drain line, and unloading throttling-valve 8 is cut in between the pressure line and control feed line 10 of valve 9. The loading line of the hydraulic control valve at least through one working section is connected to the drain line in the working position of the slide valve and disconnected from it in the neutral position of the slide valve. Valve 11 limits the maximum pressure. The hydraulic control valve may have working sections through which the loading line is not connected to and disconnected from the drain line at a change of the slide valve position, for example, two-position section 1 (2). EFFECT: enhanced reliability. 1 dwg