FEEDBACK SHAFT EXTENDING BETWEEN SWASHPLATE AND DISPLACEMENT CONTROL VALVE

摘要

FEEDBACK SHAFT EXTENDING BETWEEN AND DISPLACEMENT CONTROL VALVE A hydrostatic pump unit is located within a housing which serves also as a hydraulic fluid sump. A displacement control valve for controlling actuators for adjusting the angular position of a swashplate of the pump unit is mounted on the exterior of the housing. Disposed along the axis about which the swashplate is adjustable and joining the swashplate to a shiftable sleeve of the control valve is a feedback shaft which acts to return the valve to a null condition when the swashplate arrives at a commanded new displacement effecting position. The feedback shaft has a passage extending therethrough which acts as a drain connection between the valve and the sump defined by the housing. A check valve is located in the passage for preventing fluid from draining from the housing when the valve is disconnected from the feedback shaft for service.