Abstract: A servo valve comprises a member disposed in a cavity and axially-moveable therein. The member includes first and second sections, a central section located between the first and second sections and first and second transition sections respectively between the first and second sections and the central section, forming respective first and second outer surfaces angled relative to the axis (X). At least one of the transition sections comprises a non-circular cross-section having a concave portion forming at least part of the respective first and second surfaces and being at least partially aligned with and facing the respective first or second nozzle opening such that rotating the member in said cavity varies the level of obstruction of the first or second nozzle openings by the first or second outer surfaces.

Abstract: A hydraulic servo valve is described herein comprising a servovalve body with first and second nozzles and a flapper provided therein, wherein said flapper is a bimorph piezoelectric flapper and comprises: a first layer of piezoelectric material and a second layer of piezoelectric material. The servovalve further comprises means for providing a positive voltage to one of said first and second layers and a negative voltage to the other of said first and second layers, and the flapper extends longitudinally between a first end and a second end. The second end of said flapper is positioned so as to be between said first and second nozzles so that said first layer faces said first nozzle and said second layer faces said second layer.

Abstract: A servo valve comprises a valve housing, a cavity formed in the valve housing and a member disposed in the cavity and axially-moveable therein. The servo valve further comprises a piezoelectric actuator configured to axially move the member, relative to the valve housing, between first and second axial positions.

Abstract: A nozzle for a servo valve comprises an annular body defining an outer circumferential surface and an inner circumferential surface of the nozzle. An annular groove is disposed around the circumference of the annular body in the outer circumferential surface. A nozzle assembly (N) for a servo valve comprises the nozzle and a nozzle housing having a nozzle cavity defined by an inner circumferential cavity surface. The nozzle housing has an annular groove disposed around the circumference of the nozzle cavity in the inner circumferential cavity surface. The nozzle is received within the nozzle cavity such that the annular grooves in the nozzle and the nozzle housing are in fluid communication with each other.

Abstract: A servo valve comprising a first fluid supply port, a fluid return port and a conduit therebetween, an elongated flapper having a portion arranged in the conduit, and an actuator configured to move the flapper in a direction orthogonal to a longitudinal axis of the flapper between a first blocking position in which it blocks the conduit such that fluid cannot flow from the first fluid supply port to the fluid return port and an first open position in which the conduit is open such that fluid can flow from the first fluid supply port to the fluid return port.

Abstract: A servo valve comprises 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, wherein the member comprises a portion with first and second cylindrical sections having a first diameter (R1, R2), a central section located between the first and second cylindrical sections and having a second diameter (R3), 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. A plurality of ports, each form a fluid passage through the valve housing and have first and second nozzles with first and second nozzle openings.