Abstract: A servo valve includes a fluid transfer valve assembly comprising a valve body having a supply port and a control port (C1). The valve body has first and second nozzles and a drive member therebetween, arranged to regulate flow of fluid from the supply port to the control port in response to a control signal. The assembly also includes a drive assembly comprising a magnetic coil and a core passing through the coil and configured to move axially with respect to the coil when the coil is powered by a current dependent on the control signal, the drive assembly arranged to move the drive member relative to the first and second nozzles in response to the control signal.

Abstract: A filter assembly for a servo valve. The filter assembly has a filter body defining a chamber; a first end cap having a first fluid outlet at a first end of the filter body and a second end cap having a second fluid outlet at a second end of the filter body. A flow restrictor restricts fluid flow between the filter body and each of the first and second fluid outlets. A spacer in the chamber spaces the first end cap from the second end cap.

Abstract: An apparatus for monitoring the pressurisation of a control valve for a hydraulic actuator and a control valve. The apparatus including a spool movable along an axis (X), wherein the spool is configured to control the flow of hydraulic fluid through the control valve based on its position along the axis (X), and wherein in an unpressurised state of the control valve the spool occupies a first axial position, and in a pressurised state of the control valve the spool occupies a second, different axial position. The apparatus also including a position sensor configured to monitor the position of the spool within the control valve and detect whether the spool occupies the first axial position or the second axial position, wherein the first axial position and the second axial position correspond to neutral positions of the spool.

Abstract: A filter assembly for a servo valve that includes a first fluid nozzle defining a first fluid passage therethrough between a first fluid inlet and a first fluid outlet and a second fluid nozzle defining a second fluid passage therethrough between a second fluid inlet and a second fluid outlet. The first and second fluid nozzles arranged in end to end abutment with each other to form a tubular fluid nozzle unit in which the first and second fluid inlets are adjacent each other, and the first and second fluid passages align to form a common fluid passage through the tubular fluid nozzle unit. The first fluid outlet is at a first end of the tubular fluid nozzle unit and the second fluid passage being at a second, end of the tubular fluid nozzle unit.

Abstract: A linear feedback travel assembly includes a first tube end, a second tube end, and a longitudinal axis. A drive rod includes a first end and a second end, and a cam includes a first end, a second end, and a wall defining a bore, a first slot, and a second slot. The cam is movable along, and rotatable about, the longitudinal axis. A first pin is movably disposed in the first slot of the cam and is fixed relative to the first tube end. A second pin is movably disposed in the second slot of the cam and connects the drive rod to the cam. When the cam moves along the longitudinal axis, the first pin moves within the first slot and rotates the cam about the longitudinal axis. The second pin rotates the drive rod as the second pin moves within the second slot of the cam.

Abstract: A single stage flapper type servovalve comprises a valve housing comprising a bore, a pair of opposed nozzles arranged in the bore and a flapper element arranged between the pair of nozzles. The valve housing further comprises a plurality of fluid ports for communicating a working fluid to and from the nozzles and in fluid communication with the housing bore. The valve housing and the nozzles are both made from a stainless steel material.

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 method of controlling a hydraulic valve includes putting a first control chamber under pressure and putting a second control chamber to return so as to cause a slide to move into one of two end positions, putting a second control chamber under pressure and putting the first control chamber to return, thereby causing the slide to move into the other one of the two end positions. An intermediate step of applying pressure to the one of the first or second control chamber that was connected to return can be provided so that both control chambers are maintained simultaneously under pressure for a determined length of time.

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 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.

Abstract: A hydraulic cylinder spool valve device, which extends and retracts a cylinder rod of a hydraulic cylinder, includes: a first spool valve having a first dead band and a first opening characteristic; a second spool valve having a second dead band and a second opening characteristic; and a controller performing communication with the hydraulic cylinder by using the first spool valve and positioning the second spool of the second spool valve within the second dead band and performing communication with the hydraulic cylinder by using the second spool valve and positioning the first spool of the first spool valve within the first dead band, and adjusting a characteristic of a switching dead band between the first opening characteristic and the second opening characteristic.

Abstract: The present disclosure relates to a servovalve assembly comprising a pair of opposed nozzles spaced apart by a first gap. A control element positioned in the first gap (G) between the pair of opposed nozzles. Each nozzle has an outlet opening. The control element has a central control portion and two resiliently deformable end portions at opposite ends of the central control portion. The central control portion is perpendicular to a central axis (C) of each nozzle outlet opening. The control element is configured such that the two resiliently deformable end portions elastically deform when the control element is placed under tension by a force applied parallel to the central control portion, so as to move the control element in a direction parallel to the central axis (C) of each nozzle outlet opening.

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 drive assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The drive assembly includes a steerable member moveable by an amount determined by the control signal to cause corresponding movement of the valve spool. The drive assembly further includes piezoelectric actuator means configured to move said steerable member in response to the control signal.

Abstract: A shift lock-out device is used with a gearbox containing one or more gears and a clutch mechanism that is operable to selectively engage the one or more gears to provide first and second gear ratios. The shift lock-out device includes a housing having an inlet port that communicates with a source of pressurized fluid and an outlet port that communicates with the clutch mechanism. A valve element is supported within the housing for movement between an opened position, wherein fluid communication is permitted from the inlet port to the outlet port, and a closed position, wherein fluid communication is prevented from the inlet port and an outlet port. A pilot control valve selectively permits and prevents the application of pressurized fluid from a pilot fluid source against the valve element to selectively move the valve element between the opened and closed positions.

Abstract: A hydraulic brake mechanism for use in hydraulic systems to provide braking of a hydraulic motor is disclosed. The brake mechanism provides proper braking under a range of operating conditions, including (1) the start of flow from the pump to the brake and motor and braking is not desired; (2) operating conditions in which constant flow is provided from the pump to the brake and motor and braking is not desired; (3) operating conditions in which abrupt decreases of flow from the pump to the brake and the motor occur, for example where flow is reduced due to being drawn by another work element or hydraulic load, but under which a reduced supply flow is still present and braking is not desired; and (4) operating conditions in which the hydraulic flow from the pump to the brake mechanism and the motor is shut off completely and braking is desired.

Abstract: A cleaning device of the present invention simultaneously cleans two different hydraulic oil tubes of an aircraft. The cleaning device has a supply flow path, a return flow path, a valved connection tube, a connection tube on-off valve and a control section. The supply flow path is connected to a supply end of a first hydraulic oil tube. The return flow path is connected to a supply end of a second hydraulic oil tube. The valved connection tube is arranged between a connection end of the first hydraulic oil tube and a connection end of the second hydraulic oil tube and fluidly connects the first and second hydraulic oil tubes. The connection tube on-off valve is arranged in a flow path of the valved connection tube and controls a flow rate of a cleaning agent flowing through the valved connection tube according to an instruction from the control section.

Abstract: An actuator device includes a first and second actuators. The actuator device comprises a control system that is configured to switch the first actuator to a standby state and switch the second actuator to an active state in response to a first condition set wherein a hydraulic value in a first hydraulic system is equal to or less than a predetermined first threshold value and a second hydraulic value in a second hydraulic system is equal to or more than the predetermined second threshold value; and in response to a second condition set wherein the first hydraulic value is equal to or less than the predetermined first threshold value, the second hydraulic value is less than the predetermined second threshold value, and a difference between a current position and target position of a cylinder of the first actuator is equal to or more than a predetermined third threshold value.

Abstract: A pressure reducer valve includes a first chamber having a first spring and a first volume for receiving an output fluid having an actual output pressure that equals the desired output pressure in response to the pressure reducer valve achieving equilibrium and a second chamber having a second spring and a second volume for receiving a return fluid having a return pressure that is less than the desired output pressure and the input pressure of an input fluid. The pressure reducer valve further includes a main shaft exposed to the first spring and the output fluid from the first chamber and the second spring and the return fluid from the second chamber such that the main shaft may move relative to the first chamber and the second chamber based on forces applied by the first spring, the output fluid, the second spring, and the return fluid.

Abstract: Hydraulic servo valve (1) comprising: a power stage (3) comprising a power distribution member able to move between two extreme positions in order to place one or more service portions (C1, C2) in communication with a feed port (P) supplying hydraulic fluid and with a return port (R); a control stage (4) for controlling the position of the power distribution member, the control stage (4) comprising a torque motor (MC) that can be operated in such a way as to actuate a fluid ejection member secured to an elastically deformable element and designed to cause a control pressure of the power distribution member to vary; characterized in that the fluid ejection member comprises a first and a second fluid injector (60, 63) which are fed by fluid feed means able to feed either just one of the first and second fluid injectors (60, 63) or both injectors simultaneously.

Abstract: A hydraulic servovalve having two stages and feedback members in which the movable power distribution member has clamp means for clamping the feedback member, while allowing a clamped portion of the feedback member at least one freedom of movement relative to the movable distribution member.

Abstract: Armature springs configured to be coupled to and bias an armature of a torque motor valve actuator to a null position are provided. The armature spring comprises a rigid central portion, opposed end portions, and a flexible portion intermediate the rigid central portion and each end portion. The rigid central portion, the opposed end portions, and the flexible portions define a variable cross section torsion bar with the flexible portions comprising reduced cross-sectional portions of the torsion bar relative to the rigid central portion and opposed end portions. Armature assemblies and torque motor valve actuators are also provided.

Abstract: A servo valve includes a valve housing, a piston cylinder disposed in the housing, a piston disposed within the piston cylinder and fluidly connected on a first end to a first fluid pressure pathway and on a second end to a second fluid pressure pathway, a flapper assembly, and a flow control element disposed in the piston cylinder in a portion of the first fluid pressure pathway. The piston is configured to translate axially within the piston cylinder in response to a pressure differential between the first fluid pressure pathway and the second fluid pressure pathway. The fluid flow control element is configured to stop a flow of fluid through the first fluid pressure pathway when the piston engages the third fluid control element.

Abstract: A servovalve torque motor includes first and second pole pieces and an armature. Each of the first and second pole pieces includes an armature face that opposes the armature. The area of the armature face of the second pole piece is smaller than the area of the armature face of the first pole piece. The unequal areas of the first and second armature faces create a bias in the servovalve torque motor while allowing the first and second pole pieces to be disposed at equal distances from the armature to define substantially equal air gaps. The inclusion of substantially equal air gaps between the pole pieces and the armature reduces the maximum flux in the armature for the same bias and torque output, compared to conventional servovalve torque motors. The reduction in maximum armature flux decreases armature saturation and improves linearity during operation.

Abstract: A control device for controlling a hydraulic consumer, is equipped with a distributing valve having a control pressure chamber and a control slide that can be displaced against the force of a spring by the build-up of a control pressure in the control pressure chamber. A pilot control valve controls the supply and discharge of control fluid into and out of the control pressure chamber. A release device is used to drive the control fluid out of the control pressure chamber, bypassing the pilot control valve.

Abstract: A valve unit 1 includes a first valve body 14 which is slidable in a valve housing 11 and a second valve body 13 which is slidable with respect to the first valve body 14, and the valve housing 11 has a first passage 11a and a second passage 11b in both of which pressure fluid flows to slide the second valve body 13, a pump port 11c, a tank port 11e, a first cylinder port 11d, and a second cylinder port 11f. A first state 1a, a third state 1c, a second state 1b, and a fourth state 1d are realized by a combination of a position of the first valve body 14 after sliding and a position of the second valve body 13 after sliding with respect to the first valve body 14.

Abstract: There is disclosed a pilot valve, especially for a servo valve, comprising an actuating motor and a hydraulic preamplifier via which a control pressure difference can be created that acts upon a main slide of a main stage. According to the invention, a blocking mechanism is embodied in the flow path of the control oil. A control duct that is connected, either directly or via a branch, to a control chamber of the main stage can be blocked by manually actuating said blocking mechanism, while the other control duct remains open. The other control duct can be blocked by actuating the blocking mechanism in the opposite direction while the first control duct remains open. A control pressure difference by means of which the main slide can be displaced into a predetermined position can be created manually by actuating said blocking mechanism.

Abstract: A servovalve assembly includes a motor having a flapper shaft. A flapper couples to a first end of the flapper shaft such that the flapper shaft orients the flapper between a first nozzle and a second nozzle of the servovalve assembly. An adjustment assembly adjusts a position of the flapper relative to the nozzles of the servovalve. The adjustment assembly enables a servovalve manufacturer to set the flapper of the servovalve at a null position without disassembling the servovalve. Rather, the manufacturer is capable of simply installing the adjustment assembly and deforming an arm portion of the adjustment assembly for proper null position calibration.

Abstract: A servovalve assembly includes a motor having a flapper shaft. A flapper couples to a first end of the flapper shaft such that the flapper shaft orients the flapper between a first nozzle and a second nozzle of the servovalve assembly. An adjustment assembly adjusts a position of the flapper relative to the nozzles of the servovalve. The adjustment assembly enables a servovalve manufacturer to set the flapper of the servovalve at a null position without disassembling the servovalve. Rather, the manufacturer is capable of simply installing the adjustment assembly and deforming an arm portion of the adjustment assembly for proper null position calibration.

Abstract: A servovalve has a sleeve having both a first metering aperture and a second metering aperture in fluid communication with a single port cavity defined by the servovalve. A spool oriented within the sleeve has a first land and a second land and defines a channel oriented between the first land and the second land. When the spool orients in a null position within the sleeve, the first land overlaps the first metering aperture and the second land overlaps the second metering aperture. As a low viscosity fluid within the servovalve assembly leaks across the first land and enters the channel, the overlap of the first and second lands with the first and second metering apertures minimizes flow of the fluid from the channel into the port cavity associated with the metering apertures. The configuration of the sleeve assembly, therefore, maintains a relatively large pressure gain within the servovalve assembly.

Abstract: A method and apparatus to attenuate a flapper valve from oscillating is presented. An inertia tube is added to the flow path of the flapper valve nozzle, which effectively produces a stabilizing pressure force on the flapper at its natural frequency. The inertia tube has a length to area ratio of greater than approximately 1000 in/in2. The addition of an inertia tube to the nozzle makes the fixed size orifice of the nozzle behave like an orifice having a size that is a function of flow frequency. The inertia tube may be a straight tube, a coiled tube, a thread passage and the like.

Abstract: A hydraulic control valve has a valve block provided with a plurality of ports, a valve body formed with ports corresponding to the ports of the valve block, and a plate disposed between the valve block and the valve body. The plate has a flow passage for providing communication between the ports of the valve block and the ports of the valve body. A filter is disposed in the flow passage.

Abstract: The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

Abstract: A high pressure fuel system includes tapped high pressure flows (22,24) with restrictors (44,46) to provide low pressure flows with which, via a valve (50) to enable either a low pressure flow to bias a main, high pressure fuel cut off valve (16) to close at a steady given rate, or a high pressure flow across a further valve (30), to close the valve (16) at a faster rate.

Abstract: A thruster valve has a continuously positionable piston between a closed position and a maximum open position. The piston moves in response to the difference in pressure between the pressure in the intermediate annulus and the pressure behind the piston. A pivotable flapper valve regulates this pressure difference. When a change in thrust is required, the position of the flapper is changed causing a change in this pressure difference which causes the piston to move until the desired thrust level is obtained.