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).