A servo valve includes a valve housing, a cavity formed in the valve housing defining an axis (X) and an axially moveable member disposed in the cavity. The member comprises flat surfaces parallel to the axis (X). A channel is formed within the cavity and a plurality of ports each forming a fluid passage through the valve housing in fluid communication with a spool and with the channel. The plurality of ports include first and second nozzles with nozzle openings, wherein in a first axial position of the member the first nozzle opening is at least substantially obstructed by the first flat surface, and in a second axial position of the member the second nozzle opening is at least substantially obstructed by the second surface, the member controlling fluid between the spool and the channel.

The present disclosure relates to a nozzle assembly for use in a servo valve. The nozzle assembly comprises three nozzle parts and a housing. The second part is coaxial with the first part and surrounds at least a first portion of the first part. The third part is coaxial with the first part, and a first portion of the third nozzle part surrounds a first portion of the second nozzle part, and a second portion of the third part is attached to a second portion of the first part. First and second nozzle parts are made of materials having approximately the same first coefficient of thermal expansion (TE.sub.1), and third part and housing are made of materials having approximately the same second coefficient of thermal expansion (TE.sub.2). TE.sub.1 is different from TE.sub.2. The interaction between the portions due to the differences in TE.sub.1 and TE.sub.2 allow the nozzle assembly to compensate for temperature fluctuations during and operation whilst remaining firmly held in position.

A servo valve includes first and second nozzles spaced apart from each other, an elongate control member positioned between the nozzles, and a solenoid assembly surrounding at least a portion of the control member. The elongate control member has a first end and an opposing second end. The control member is configured to translate in response to the solenoid assembly being energised, such that the first end is moved towards the first nozzle and the second end is moved away from the second nozzle or the first end is moved away from the first nozzle and the second end is moved towards the second nozzle.

A nozzle with changeable press fit and a method for calibrating a nozzle is described. The nozzle may be used in a nozzle/flapper type servovalve. The method comprises the steps of providing a nozzle within a cylindrical body defining a cylindrical bore, the nozzle having a tubular shape with an outer cylindrical surface and an inner radial surface., the method further comprises the steps of positioning a first, tubular locking member within the nozzle, and axially moving the first, tubular locking member within the nozzle. The first tubular locking member is configured to cause the nozzle to become positionally fixed at a selected position within the bore in response to the first, tubular locking member being axially moved relative to the nozzle. A nozzle positioning system is also described herein.

A torsion bridge for use in a servovalve includes a body extending along and adapted to rotate about a first axis; a passage extending through the body along a second axis substantially perpendicular to the first axis, the passage defining a first cylindrical surface having a radius R.sub.1; an annular groove formed in the first cylindrical surface. The annular groove includes: a second cylindrical surface extending substantially in the direction of the second axis, the second cylindrical surface having first and second ends and a radius R.sub.2, where R.sub.2 is greater than R.sub.1; a first annular surface joining the first cylindrical surface to the first end of the second cylindrical surface; and a second annular surface joining the second end of the second cylindrical surface to the first cylindrical surface.

A valve device with a valve housing, which is penetrated by a fluid channel, which extends from an inlet connection to an outlet opening and in which a valve member is arranged, which is designed to regulate a cross-section of the fluid channel, with an electric drive device to influence a position of the valve member in the fluid channel including a stator that is fixed on the valve housing and an armature arranged so as to be movable relative to the stator wherein the armature and the valve member are arranged on a dimensionally-stable connection part, which is pivotably mounted on the valve housing with a flexure, wherein the flexure is designed for an electric connection of the armature to an electric connection device designed on the valve housing and wherein the connection part forms the valve member or carries the valve member.

A piezoelectric ring bender servo valve assembly reduces mechanical wear by removing mechanical components used in prior art servo valves. The assembly does not use torque motor, flapper, and feedback spring. In this manner, no moving parts are required, which reduces maintenance and costs. A pair of piezoelectric ring benders mount adjacently to a pair of nozzles. The piezoelectric ring benders independently regulate the flow of fluid through the nozzles by moving between an open position to enable flowage, and a closed position to restrict flowage. A linear position sensing device measures and provides feedback about the spool position to a valve controller. The valve controller allows the spool valve to move until valve position achieves command position and the force on the spool valve is in equilibrium with pressure difference across spool valve. An H-bridge operable to switch the polarity of a differential pressure applied across to a load.

A valve body for a servovalve is provided comprising: a first surface adapted to extend parallel and adjacent to a substantially flat pole piece surface of a pole piece in use; and attachment features provided on the first surface for attaching the valve body to the pole piece in use, wherein the first surface is contoured such that, in use, an area of the first surface surrounding the attachment features is in contact with the substantially flat pole piece surface and an area of the first surface removed from the attachment features is not in contact with the substantially flat pole piece surface.

The present disclosure relates to a nozzle assembly for a servo valve. The nozzle assembly comprises a nozzle including a nozzle inlet and a nozzle outlet, and a tubular filter mounted to the nozzle for filtering fluid flowing into the nozzle through the nozzle inlet.

A torque motor for a servovalve, said torque motor comprising a set of pole pieces comprising a first pole piece and a second pole piece. An armature is also provided between the first pole piece and the second pole piece, said armature configured to provide air gaps (AG1-AG4) between the armature and the first pole piece, and the armature and the second pole piece. The armature is configured to rotate about a centre point (CP). The set of pole pieces is also adapted to rotate around the centre point (CP) such that the air gaps (AG1-AG4) can be adjusted.