Hydraulisches Ventil mit integriertem Hilfsventil

摘要

A fluid controller (15) is provided of the type having a primary valve member (53) and a follow-up valve member (55). The controller includes a housing (41) defining main fluid ports (27,29) connected to a steering cylinder (19), and also defines auxiliary fluid ports (31,33), connected to an auxiliary fluid motor (21). The spool and sleeve cooperate with the housing to provide main control valving (35) controlling the flow of fluid to the steering cylinder in response to relative rotation of the spool and sleeve, and auxiliary control valving (35), controlling the flow to the auxiliary motor in response to axial motion of the sleeve, relative to the spool and housing. By performing both the main and auxiliary valving in the spool and sleeve, the main valving (35) is automatically given priority over the auxiliary valving (37), without the need for any expensive, complicated controls or interface between the two types of valving.