Hydraulic servo valve for hydraulic servo steering system that provides steering assistance force for driver of motor vehicle, has shaft and sleeve defining closable fluid connection between pressure-control groove and valve return line

摘要

The valve (10) has a valve shaft (12) rotatable around a valve axis (A). A valve sleeve (14) is rotated relative to the valve shaft. The sleeve and shaft control a valve flow rate. Control grooves (24, 24') are formed in the shaft and the sleeve. One of the grooves (24') is formed as a pressure-control groove that is in connection with a valve inlet (26). The shaft and the sleeve define a closable fluid connection (28) between the pressure-control groove and a valve return line (22), where the connection is provided in the form of a circular gap between the sleeve and a closure element (30).