Abstract: 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 (TE1), and third part and housing are made of materials having approximately the same second coefficient of thermal expansion (TE2). TE1 is different from TE2. The interaction between the portions due to the differences in TE1 and TE2 allow the nozzle assembly to compensate for temperature fluctuations during and operation whilst remaining firmly held in position.

Abstract: A plug for sealing a passage extending about a longitudinal axis (A) comprises a shell having a circumferential wall extending between an end wall and an opening, and an internal cavity extending axially within the shell, and an expander having a head and a shank extending axially from the head, the head retained with the cavity and the shank extending axially through the opening of the cavity, wherein the circumferential wall comprises an inner surface having at least a first region and a second region, the second region proximate the opening and the first region adjacent to the second region and extending therefrom towards the end wall, the inner surface in the first region tapering inwardly relative to the longitudinal axis (A) to provide a first angled ramp, and the inner surface in the second region tapering further inwardly to provide a second angled ramp.

Abstract: A torque limiter assembly is disclosed comprising a housing having at least one first engagement member, an input shaft that is rotatable relative to the housing and having at least one second engagement member; and an electromagnet. The electromagnet 10 is arranged and configured such that when activated it generates a magnetic field that moves the at least one first engagement member relative to the at least one second engagement member, such that the first and second engagement members engage each other and stop or inhibit rotation of the input shaft relative to the housing.

Abstract: A nozzle of or for a servo valve comprises a nozzle element having a fluid outlet at a first axial end and a tubular body extending from the first end to an opposed, second axial end. The nozzle further comprises a plug element mounted in and closing the second axial end of the tubular body, thereby defining an internal cavity within the tubular body. One or more openings are formed through the tubular body to fluidly communicate with the internal cavity. A filter may be mounted across the internal cavity at a position axially intermediate the openings and the fluid outlet.

Abstract: A method of manufacturing a hydraulic plug. A shell with a circumferential wall, a sealed end, an open end and an axially extending cavity within is provided in which the cavity is defined by an internal surface with an inner diameter which narrows towards the open end. A head of an expander is inserted into the cavity, the expander further comprising a stem extending from the cavity for applying a tensile force (T) to the head. A sleeve is provided on a stem side of the head extending into the cavity, an end of the sleeve adjacent the head having an inner diameter which is less than a maximum outer diameter of the head. The sleeve is formed by expanding the sleeve by forcing the head into the end of the sleeve through urging the sleeve and/or expander towards the other in an axial direction.

Abstract: A servovalve includes a fluid transfer valve assembly comprising a supply port and a control port and a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal. The servovalve also includes a jet pipe assembly configured to direct fluid to the ends of the spool to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The jet pipe assembly comprises a jet pipe a connector header fluidly connecting the jet pipe to a nozzle. The spool has one or more openings 28 is provided in the spool such that fluid from the supply port flows into the interior of the spool and into the jet pipe.

Abstract: There is provided a method of manufacturing a torsion spring, comprising providing a section of sheet metal, and forming the torsion spring from the section of sheet metal.

Abstract: A transmission shaft comprising: an input side for inputting torque; an output side for outputting torque; a rod extending in a longitudinal direction between the input side and the output side to transfer torque along the transmission shaft, the rod comprising a first end provided at the input side, a second end provided at the output side and a torsional compliant section extending therebetween providing the transmission shaft with a torsional stiffness. A casing extends around the torsional compliant section and is arranged to resist deflection of the rod without increasing the torsional stiffness of the transmission shaft.

Abstract: An electrical assembly comprises a wall having an opening, one or more electrical leads extending through the wall opening and a grommet arranged in the wall opening. The grommet comprises a body of resilient elastomeric material having at least one hole extending axially therethrough for receiving a respective individual electrical lead. The grommet body has a portion with an external diameter Db which, in an uncompressed state of the grommet is greater than the internal diameter (Dop) of the wall opening whereby when the grommet inserted in the wall opening, the grommet body is compressed into sealing and clamping engagement with the electrical lead.

Abstract: A servovalve includes a fluid transfer valve assembly comprising a supply port and a control port a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a jet pipe assembly configured to direct fluid to the ends of the spool to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The jet pipe assembly includes a jet pipe and a connector header fluidly connecting the jet pipe to a nozzle via which fluid is directed to the spool ends. One or more openings is provided in the spool such that fluid from the supply port flows into the interior of the spool and into the jet pipe and to the nozzle via the connector header.

Abstract: There is provided a method of assembling a torque motor. The method comprises fastening the torque motor to a support such that any magnetic elements of the torque motor are substantially fixed in position with respect to the support, but without securing an armature to the torque motor, locating the armature of the torque motor around a fixed element of the torque motor such that the armature is able to move with respect to the fixed element, moving the armature with respect to the fixed element whilst the magnetic elements of the torque motor are substantially fixed in position with respect to the support, so as to position the armature in an in use orientation or position, and then attaching the armature to the fixed element in the in use orientation or position.

Abstract: The disclosure provides a method of securing a feedback spring relative to a spool of a servovalve, the method comprising inserting the feedback spring at least partially into an internal cavity of the spool, inserting two fixing members into the internal cavity such that they each oppose a portion of the feedback spring, bringing the fixing members into respective set positions, such that the fixing members clamp the feedback spring and prevent relative movement between the feedback spring and the spool, and securing the fixing members in their respective set positions, such that the fixing members remain in their clamping positions and prevent relative movement between the feedback spring and the spool.

Abstract: The present disclosure relates to coupling assemblies for drive shaft assemblies. The coupling assembly comprises a first portion and a second portion which are configured to couple to one another such that the second portion is capable of rotationally driving the first portion about an axis of rotation. The first portion is provided with a first magnet and the second portion is provided with a second magnet. The first and second magnets are arranged to repel each other such that the first and second portions are biased away from each other in an axial direction that is parallel to the axis of rotation.

Abstract: The present disclosure provides a heat exchanger system for a servovalve, comprising a base comprising a supply port in fluid communication with a return port, a first passage for fluid connection to a source of cooling fluid, and a second passage in fluid communication with the return port. The system further comprises one or more pipes located over a surface of the base, the one or more pipes fluidly connected between the first passage and the second passage, such that in use cooling fluid may flow from the first passage to the second passage via the network of pipes.

Abstract: A spool for a spool valve having a longitudinal axis (L). The spool comprising: a plurality of lands each having a substantially radially extending metering edge and an axially extending circumferential surface; a plurality of grooves separating each of the plurality of the lands; and a guiding section located axially between at least one land and an adjacent groove. The guiding section comprising a plurality of circumferentially spaced guiding surfaces being substantially flush and contiguous with the circumferential surface of the land, wherein the guiding section allows fluid communication between the groove and the metering edge of the land.

Abstract: A valve assembly includes a valve housing having a bore formed therein. The bore has an axis A and comprises a circumferentially extending groove formed at an end portion. An axially outer wall of the groove includes at least two circumferentially spaced radially inwardly extending retaining elements defining an axial slot therebetween. An end cap is received in the end portion of the bore and closes the end of the bore. The end cap includes a retaining portion that includes at least one radially outwardly extending retaining element which is shaped to be insertable through the axial slot into the groove and rotatable therein to a retaining position in which the radially outwardly extending retaining element aligns with one of the radially inwardly extending retaining elements to prevent axial withdrawal of the end cap from the bore.

Abstract: A torque motor for a servovalve is provided, the torque motor comprising an armature and a first pole piece. The first pole piece has a first portion and a second portion that is selectively moveable relative to the first portion such that a size of an air gap formed between the second portion and the armature is adjusted in response to the movement of the second portion relative to the first portion.

Abstract: A valve body for a servovalve is provided, the valve body comprising: a first surface; a second surface offset from the first surface; a first passage extending through the body between the first and second surfaces from a first side of the body to a second side thereof; a second passage extending from the first surface towards the second surface and intersecting the first passage; a supply port joined with the first passage; a control port joined with the first passage; a return port joined with the first passage, wherein the return port comprises a third passage extending through the body between the first and second surfaces from a third side of the body to a fourth side thereof and intersecting with the first passage.

Abstract: A coupling for allowing torque transmission between a first and second shaft, the coupling comprising: a cup-shaped portion provided at a first end of said first shaft and a first end of said second shaft being positioned within said cup-shaped portion; and said coupling further comprising a biasing means positioned between said first and second shafts, such that said biasing means is in contact with both of said first and second shafts. A shaft system can include the first coupling in combination with a third shaft and a second coupling that is provided between the third shaft and either a second end of said first shaft or a second end of said second shaft. The second coupling is identical to the first coupling.

Abstract: A method of manufacturing a hydraulic plug includes providing a shell comprising a circumferential wall, a sealed end, an open end and a cylindrical cavity opening to the open end is provided. The open end of the shell is wider externally than the sealed end. A head of an expander is inserted into the cavity. The head of the expander has a convex contact surface which is rounded in an axial direction (A) of the cavity. A region of the shell adjacent its open end is plastically deformed causing material from the circumferential wall of the shell to be displaced radially inward around the head of the expander to form a constricted opening retaining the expander within the cavity. The deforming reshapes an internal surface of the cavity from a cylindrical to a non-linear shaped ramp leading up to a constricted opening.