Abstract: Differential pressure sensor mechanisms include core members acted upon by pressure sensing plungers at opposite ends of the core members to cause axial movement of the core members relative to a linear variable position sensor when unequal force balances are applied to the respective plungers, and centering springs for centering the core members with respect to the sensor when equal force balances are applied to the respective plungers. The centering springs desirably flex equally in both directions to keep reversing stress levels to a minimum and are essentially unloaded in the null or lower load region of operation to minimize the possibility of induced plunger side loading in the most active and critical region of performance. Carriage members desirably support opposite ends of the core members for coaxial movement relative to the sensor.

Abstract: Linear direct drive motor includes a pair of axially spaced, relatively fixed stator poles and an armature mounted on a motor shaft for axial movement between the stator poles. The ends of the motor shaft are supported by centering springs which permit axial movement of the shaft and thus the armature relative to the stator poles. Positive stops are located between the stator and stator poles for preventing armature overtravel. Extending between the stator poles is a sleeve member which supports a ring magnet in radially spaced relation from the armature. Adjacent opposite ends of thee ring magnet are a plurality of layers of electrical coils, with the layers adjacent one end of the magnet being paired with different layers at the other end to provide redundant electrical channels and symmetric motion behavior.

Abstract: Limited angle torque motor includes a secondary magnetic flux path of relatively small cross-sectional area which increases the rotational and torque gains of the motor in a localized area about the motor null as if the magnetic air gap of the motor were substantially reduced so that when properly matched with a direct drive valve having significant valve overlap, a desired linear valve flow gain can be achieved. As the motor flux increases with applied current, the secondary flux path saturates, whereby further increases in current above a specified level are directed into the main pole structure magnetic flux path as if the secondary flux path did not exist.

Abstract: A flow control valve assembly including a valve having open and closed positions and a limited angle torque motor having two angular rotor positions corresponding to the open and closed valve positions that are stable in the absence of an applied electrical signal. The valve motor includes magnetic pole pieces forming a concentric shell around the motor shaft that include air gaps, disposed generally parallel to the axis of rotation of the shaft. Pole blades adjacent the rotor are magnetically linked to the pole pieces by flanges disposed at the rotor ends. Two alternative minimum reluctance flux paths are provided for a permanent magnet that is mounted on the rotor with its poles transverse to the axis of rotation. The two minimum reluctance paths provide the stable rotor positions. A magnetic flux sensor disposed in or proximate one of the air gaps is employed with a relatively high frequency electrical signal to determine relative rotor and valve positon.

Abstract: Limited angle torque motor includes a rotor assembly having one or more permanent magnets which are magnetized in the diametrical direction and a stator assembly including a pair of circumferentially spaced stator magnetic pole pieces, each having a stator pole flange at the opposite end thereof. Each stator pole piece has a greater circumferential width in the region of the respective stator pole flanges to increase the amount of magnetic material in such region where the flux density is the highest. Surrounding the stator assembly is a magnetic housing which desirably effectively has no air gap therein.

Abstract: Ball drive mechanism includes a ball-like member on an eccentric output shaft of a rotary force motor which is received in a transversely extending cylindrical socket on a valve member. The outer diameter of the ball-like member is substantially the same as the inner diameter of the cylindrical socket to provide line contact therebetween at some distance radially offset from the longitudinal axis of the valve member which is at least as great as the eccentric offset, whereby the rotary output of the rotary force motor is translated into both linear and rotary movement of the valve member.

Abstract: Multiple drive paths are provided between the valve plunger and force motor of a direct drive valve and force motor assembly whereby should one of the drive paths fail, the force motor can still be used to drive the valve plunger through another drive path. One of the drive paths consists of a drive shaft having one end drivingly connected to an eccentric on the motor output shaft and the other end connected to the end of the valve plunger remote from the motor output shaft. The drive shaft is desirably provided with an enlarged head portion having a flat annular surface on the axial inner end thereof in close proximity to a corresponding flat end face on the end of the valve plunger closest to the motor output shaft, whereby should the valve plunger break, the drive shaft will hold the valve plunger together and allow for degraded valve performance.

Abstract: A direct drive valve and force motor assembly including interchangeable stator assembly and method for accurately setting the magnetic spring null of the motor with respect to the servo valve hydraulic null independent of the actual motor stator assembly, whereby the motor stator assembly may be configured as an interchangeable plug-in module with interface electrical connector. This is accomplished by using a simple fixture which simulates the motor stator assembly and senses rotor magnet position. The stator simulating fixture may be used to rotatably adjust the position of the rotor casing so that the magnetic spring null corresponds to the hydraulic valve null. Both the stator simulating fixture and motor stator assembly include an index pin engageable with a stator alignment keyway in the rotor casing for maintaining the desired orientation therebetween. Also, rotor over-travel stops keyed to the rotor casing may be centered during the nulling process.

Abstract: A two-pole limited angle torque motor including a rotor assembly having one or more permanent rotor magnets and a stator assembly including a stator coil and a pair of circumferentially spaced stator pole structures. Each pole structure includes a generally axially extending stator pole blade about which the stator coil circumferentially extends. A radially outwardly extending flange is at one end of one of the stator pole structures and at the opposite end of the other stator pole structure. The stator pole blades have a greater radial thickness adjacent the flanges thereof than at the opposite end of the blade to reduce the magnetic flux density of the stator pole structures in the region of the blades adjacent the flanges thereof. Also, the axial outer end faces of the flanges desirably protrude axially outwardly adjacent the radial inner ends thereof to make use of the fringing fields of the rotor magnet at the ends of the rotor assembly to increase the reluctance torque of the motor.

Abstract: Limited angle torque motor includes a rotor assembly having one or more permanent magnets which are magnetized in the diametrical direction and a stator assembly having a plurality of axially spaced pairs of stator pole pieces, each pair having a stator coil extending circumferentially therearound. Each stator pole piece includes a generally axially extending pole blade and a radially outwardly extending flange portion at one end only of each pole piece, said flange portions being at opposite ends of the pole pieces of each pair. One or more of the stator coils and associated pairs of pole pieces may be rotationally offset with respect to one or more other coils and associated pairs of pole pieces to provide for the reshaping or widening of the resulting magnetic reluctance and interaction of magnetic fields torques versus rotation characteristics for a given motor design.

Abstract: Limited angle torque motor includes a motor power section comprising a rotor assembly having one or more permanent rotor magnets which are magnetized in a diametrical direction and a stator assembly surrounding the rotor assembly. The magnetic flux in the motor power section produces an inherent magnetic centering spring rate tending to keep the rotor assembly at the midpoint of its rotational angle range. However, when a direct or pulse width modulated current is applied to the stator windings, a cross flux is produced through the stator and rotor assemblies of the motor power section which produces the desired limited rotational angle range for the rotor assembly. The motor also includes a separate magnetic centering spring section which provides another centering spring function in addition to the basic centering spring function inherent in the motor power section.

Abstract: An electro-mechanical direct drive valve servo system for an aircraft including a drive mechanism that couples the rotary output motion of a rotary force motor to linear motion at a sliding-type valve. The drive mechanism includes a pair of axially spaced rotary members connected to the force motor and a wobble member journaled between and canted by the rotary members with axial thrust bearings interposed between axially aligned opposed planar faces of the rotary and wobble members. A radial output arm on the wobble member is connected to the valve and is constrained for arcuate nutating movement whereby controlled rotation of the rotary member effects nutating movement of the wobble member and output arm which movement effects controlled linear movement of the valve. Additional control inputs such as braking and recentering function inputs are accommodated by the drive mechanism at its input end to take advantage of the mechanism's inherent gearing force ratio.

Abstract: A control actuation system for an aircraft including an electromechanically controlled, hydraulically powered actuator for driving a main control valve of a dual hydraulic servo-actuator control system. The actuator includes a tandem piston connected to the main control valve which is controllably positioned by a staged valve of relatively short stroke whereby a force motor of minimum size and energy requirements may be used to directly drive the valve. The staged valve includes a linearly movable valve plunger for simultaneously controlling the differential application of fluid pressure from respective hydraulic systems on opposed pressure surfaces of respective piston sections to cause movement of the piston in response to relatively short axial movement of the valve plunger as long as at least one hydraulic system remains operative.

Abstract: A two pole stationary coil rotary magnet motor which provides for increased work and reduced rotary inertia. The motor consists of two main assemblies, a rotor assembly contained within a rotor casing and a stator and housing assembly surrounding the rotor casing. One end of the casing is closed, whereas the other end is open to eliminate the need for a dynamic shaft seal. Fluid enters the casing at the open end thereof to provide a lubricating fluid for the rotor bearings and a heat conductive path. The rotor casing isolates the critical movement of the rotor from the contaminated atmosphere of the stator environment and allows replacement of the stator assembly without disturbing the rotor assembly. A permanent magnet rotor may be formed using one or more rare earth magnets which may be suitably bonded to the rotor shaft. A protective cover surrounds the rotor magnets to eliminate potential rotor magnet breakage contamination.

Abstract: A 2-pole limited angle torque motor including a rotor assembly having one or more permanent magnets which are magnetized in the diametrical direction and a stator assembly having a pair of stator magnetic pole blades surrounded by a high density layer wound stator coil, with stator pole flanges at opposite ends of the stator magnetic pole blades which create a cross flux through the stator and rotor assemblies that produces a limited angle turning torque in the motor. The permanent rotor magnets along with stator magnetic poles and magnetic housing produce a magnetic reluctance torque that can be controlled to obtain a desired magnetic centering or de-centering spring rate for the rotor at a particular torque or power level. A magnetically saturating flux path may also be made to occur in the motor at the end of the rotational design stroke of the motor to provide a magnetic stop for the rotor shaft.

Abstract: Motor includes an internal torsion spring which provides for null centering of the rotor assembly while minimizing bearing load reactions and related friction. Two such centering springs may be provided whereby in the event one spring should fail, the other spring will still be operative to perform the desired null centering function. Also, an internal leaf spring interiorly of the rotor casing absorbs the full stroke rotor inertia without part damage or deformation. The null position bias of a motor driven valve may be established by adjustment of a pair of set screws which adjust the rotor assembly off null without inducing undesirable friction. The stator electrical torque null of the motor may also be set by providing an adjustable eccentric pin in the stator housing which is engageable in a notch in the rotor casing.

Abstract: A redundant control actuation system for an aircraft including an electro-mechanically controlled, hydraulically powered actuator for driving a main control valve of a servo-actuator control system. The actuator includes a tandem piston connected to the main control valve and a force motor driven tandem pilot valve axially movable in the piston for simultaneously controlling the differential application of fluid pressure from respective hydraulic systems on opposed pressure surfaces of respective piston sections to cause movement of the piston in response to relative axial movement of the pilot valve as long as at least one hydraulic system remains operative. The piston pressure surfaces are sized and arranged to minimize force unbalance on the piston due to pressure variations in the hydraulic systems. Also, a pilot valve centering spring device may be provided to minimize undesirable transient motions during system turn on and shut down.

Abstract: An electro-mechanical direct drive valve servo system for an aircraft including a drive mechanism that couples the rotary output motion of a rotary force motor to linear motion at a sliding-type valve. The drive mechanism includes a pair of axially spaced rotary members connected to the force motor and a wobble member journaled between and canted by the rotary members with axial thrust bearings interposed between axially aligned opposed planar faces of the rotary and wobble members. A radial output arm on the wobble member is connected to the valve and is constrained for arcuate nutating movement whereby controlled rotation of the rotary member effects nutating movement of the wobble member and output arm which movement effects controlled linear movement of the valve. Additional control inputs such as braking and recentering function inputs are accommodated by the drive mechanism at its input end to take advantage of the mechanism's inherent gearing force ratio.

Abstract: A free piston engine pump (FPEP) converts combustion energy into hydraulic power in an efficient, controlled and relatively uncomplicated manner, for example, for vehicle propulsion, auxiliary system power, etc. The FPEP is substantially naturally mass balanced having opposed engine pistons driving respective in-line hydraulic pumps. An adjustable accumulator with a deformable fluid-tight chamber containing a compressible fluid stores and delivers energy for compression, and an arrangement of control valves and check valves enables selective operation of the FPEP in primary (high flow) and secondary (high pressure) modes. Plural FPEP's may be interfaced for parallel operation sharing common elements and functions. Cycle rate, intermittent operation and start-up also may be controlled. Electronic monitoring and control of one or more operational parameters of a FPEP also are disclosed.

Abstract: In a free piston engine pump means are provided for obtaining a variable energy rate output and for controlling acceleration and deceleration of the piston masses. In particular a second high output work rate phase is obtained at the end of the power stroke helping to decelerate the piston masses, and a high input work rate phase is provided at the beginning of the return compression stroke to accelerate the piston masses while maintaining the total input energy of the return stroke relatively constant from cycle to cycle and substantially independent of the total output energy of the power stroke.