CONTROL VALVE FOR CONTROLLING FLOW OF HYDRAULIC FLUID

摘要

The present invention relates to a control valve for controlling flow of hydraulic fluid. The control valve comprises: a valve housing ( 10 ); a sleeve ( 11 ) slidable in a valve chamber in the valve housing ( 10 ); a first fluid conduit ( 12 ) for connecting the valve chamber to a source of pressurised hydraulic fluid; a second fluid conduit ( 14 ) for connecting the valve chamber to a fluid return for returning hydraulic fluid to a reservoir; and a third fluid conduit ( 16 ) for connecting the valve chamber to deliver hydraulic fluid to and receive hydraulic fluid from apparatus which uses the hydraulic fluid flow controlled by the control valve. The sleeve ( 11 ) is a tubular sleeve having, a tubular passage therethrough. The valve housing has a pair of spaced apart valve seat surfaces ( 22, 23 ), a first valve seat surface ( 22 ) which is engageable by a first end of the tubular sleeve ( 11 ) and a second valve seat surface ( 23 ) which is engageable by a second end of the tubular sleeve ( 11 ). The third fluid conduit ( 16 ) opens on to the valve chamber by way of a port which is surrounded by the first valve seat surface ( 22 ).