Spool servo valve

A servo valve comprising:

• a valve housing;
• a cavity formed in the valve housing and defining a longitudinal axis (X);
• a member disposed in the cavity and axially moveable therein along said longitudinal axis, wherein the member comprises:
• first and second cavity sealing sections, having first and second cross-sectional areas, for engaging an inner surface of the valve housing defining the cavity;
• first and second nozzle obstructing sections arranged between the first and second cavity sealing sections;
• a middle portion located between the first and second cavity sealing sections and having a third cross-sectional area smaller than both the first and second cross-sectional areas so as to form a channel within the cavity bounded by the first and second nozzle obstructing sections;
• and
• first and second surfaces formed respectively on the first and second nozzle obstructing sections;
• a plurality of ports, each forming a fluid passage through the valve housing in fluid communication with the channel, the plurality of ports comprising first and second ports having first and second nozzles with first and second nozzle openings for providing fluid communication between the channel and a spool, wherein in a first axial position of the member the first nozzle opening is at least substantially obstructed by the first surface and the second nozzle opening is at least substantially unobstructed by the second surface, and in a second axial position of the member the second nozzle opening is at least substantially obstructed by the second surface and the first nozzle opening is at least substantially unobstructed by the first surface;
• at least one actuator configured to axially move the member within the cavity;
• and
• a spring arranged between first and second axial ends of the valve housing, the spring operatively connected with the member to bias the member towards a neutral position.