Servo valve

A servo valve comprising:

• a valve housing;
• a cavity formed in the valve housing and defining a longitudinal axis (X);
• and
• a member disposed in the cavity and axially-moveable therein, the member comprising:
• first and second cylindrical sections having a first radius (R1, R2);
• a central cylindrical section located between the first and second cylindrical sections and having a second radius (R3) smaller than the first radius (R1, R2);
• and
• first and second frusto-conical sections connecting the first and second sections to the central section and forming respective first and second frusto-conical surfaces,
• wherein the member defines an annular channel radially between the member and the valve housing, and the annular channel is bounded by the first and second cylindrical sections,
• wherein the valve housing comprises a plurality of ports, each forming a fluid passage through the valve housing in fluid communication with the annular channel, the plurality of ports comprising first and second ports each defining a diameter and having first and second nozzles with first and second nozzle openings for providing fluid,
• wherein the first and second nozzle openings each having diameters smaller than the diameter of their respective port,
• wherein, in a first axial position of the member the second nozzle opening is at least partially engaged with and at least substantially obstructed by the second frusto-conical surface and the first nozzle opening is at least substantially unobstructed by the first frusto-conical surface, and in a second axial position of the member the first nozzle opening is at least partially engaged with and at least substantially obstructed by the first frusto-conical surface and the second nozzle opening is at least substantially unobstructed by the second frusto-conical surface.