Abstract: A contactless rotary shaft position sensor provides for precision computation of shaft angle for a wide range of input shaft rotational angles. The sensor includes two annular two-pole magnets which are connected by a precision, motion-transmitting gear train. An optional second gear train between one of the magnets and the input shaft can provide additional angular rotation scaling to accurately measure either fractional or a large number of multiple turns of the input shaft. The gear ratios are selected such that one of the magnets does not rotate more than one revolution. Pairs of ratiometric Hall-effect or magnetoresistive sensors provide differential voltage signals which are used for sensing angular position of each magnet over a full 360 degrees of rotation. The single-turn magnet provides an absolute, coarse indication of input shaft rotation with a typical accuracy of 2%. The gear ratio between the magnets produces several turns of the second magnet for each turn of the single-turn magnet.

Abstract: A contactless rotary shaft position sensor provides for precision computation of shaft angle for a wide range of input shaft rotational angles. The sensor includes two annular two-pole magnets which are connected by a precision, motion-transmitting gear train. An optional second gear train between one of the magnets and the input shaft can provide additional angular rotation scaling to accurately measure either fractional or a large number of multiple turns of the input shaft. The gear ratios are selected such that one of the magnets does not rotate more than one revolution. Pairs of ratiometric Hall-effect or magnetoresistive sensors provide differential voltage signals which are used for sensing angular position of each magnet over a full 360 degrees of rotation. The single-turn magnet provides an absolute, coarse indication of input shaft rotation with a typical accuracy of 2%. The gear ratio between the magnets produces several turns of the second magnet for each turn of the single-turn magnet.

Abstract: Paper drive unit instability that includes a variable displacement hydraulic motor (34), a rotary output (48), and a displacement controlling wobbler (36, 40) in the case of an aiding load can be avoided through the use of a double acting hydraulic actuator (42, 44) connected to the wobbler (36, 40) along with a control valve (30) including a single spool (80) connected to the motor (34), and wobbler control pilot valve (62) and to the actuator (42, 44) for a) controlling the speed and direction of rotation of the motor output (48); and b) controlling the actuator (42, 44) to maintain minimum displacement of the motor 34 when an aiding load occurs. System optimization can be achieved by changing the differential pressure setting in response to the available system pressure.

Abstract: A hydromechanical control system for a power drive unit having a hydraulic motor of the axial piston type, including a wobbler to vary the axial displacement of the pistons of the motor. A cylinder block is coupled to a shaft for rotation therewith. The cylinder block defines a plurality reciprocally movable therein. A port plate is provided at one end of the cylinder block, with kidney-shaped ports concentric with the axis of rotation of the cylinder block, in alignment with the cylinders and in communication with fluid supply and return conduits. A solenoid-operated piston-cylinder device rotatably adjusts the position of the port plate to adjust the positions of the ports relative to the incline plane of the wobbler.

Abstract: In order to protect an actuator system for a movable surface in a reliable manner, while also protecting the movable surface in the event of a system failure, the actuator system includes a power drive unit connected to one end of an input shaft. An actuator is disposed on the input shaft having multiple output stages normally driven by the power drive unit through the input shaft with the mutiple output stages being operatively associated with the movable surface for driving movement thereof. In order to provide dual load path shafting together with incorporating fail safe actuator construction, the actuator system also includes a feedback shaft extending from the actuator to the power drive unit and a torque sensor operatively associated with the feedback shaft.

Abstract: In order to enhance performance of an aircraft while at the same time utilizing redundant aircraft hydraulic power in an efficient manner, an actuator system for a nozzle flap of an aircraft engine is provided. The actuator system includes a power drive unit in operatively associated relation with drive transmitting gearing at a single location together with an actuator driven by the power drive unit through the drive transmitting gearing, and the actuator includes output drive gearing operatively associated with the nozzle flap for driving the nozzle flap at spaced apart locations. With this arrangement, the nozzle flap is driven at spaced apart locations by the power drive unit from a single location through the actuator to permit downsizing of components with consequent weight reduction to achieve enhanced performance.

Abstract: A multiple-stage geared rotary actuator having a plurality of balanced compound differentials providing a multiple-stage output and for converting a high-speed, low-torque input to a low-speed, high-torque output for moving a member, such as an aircraft flight control surface. The balanced compound planetary differentials each have a plurality of planet gear shafts with a center gear and outer gears at opposite sides of the center gear and with the tubular planet gear shafts of the planetary differentials being in axial alignment. The maximum deflection resulting from bending forces acting on the tubular planet gear shafts is minimized by changing the boundary conditions at the ends of the planet gear shafts.

Abstract: A hydraulic pressure intensifier for boosting normal system pressure in a hydraulic system to a higher level in order to increase the force provided by a pressure-operated actuator. The hydraulic pressure intensifier has a motor-pump unit with a rotatable cylinder block with cylinders defining piston chambers and each having a movable piston therein. A wobbler controls the stroke of the pistons and the motor-pump unit functions as both a pump and a motor by means of porting to said cylinders including a supply pressure port, an intensified pressure port and a return pressure port. The motor-pump unit has normal maximum and minimum speed limits and when operating at different flow rates the speed thereof varies accordingly. In order to maintain the speed of the motor-pump unit within normal limits, the wobbler is adjustable to vary the stroke of the pistons and thereby vary the speed of rotation of the cylinder block for the same rate of fluid flow.

Abstract: In many aircraft, there are flight control surfaces positioned by mechanical actuation systems that are driven by hydraulic power drive units. There are also devices for transmitting hydraulic power from one aircraft hydraulic system to another in the event that one of the system's pumps fails. An integration of structure to perform both of these functions in a single unit would result in a reduction in cost and weight as well as increased reliability. The integrated power drive and power transfer system has a pair of variable displacement hydraulic devices each in a separate hydraulic circuit and each having a drive shaft connected into a summing gear train connected to an output shaft.

Abstract: A failure detection mechanism for a geared rotary actuator having plural output stages. Each output stage has a planetary gearing set and the failure detection mechanism senses relative movement between planet gear shafts of adjacent planetary gearing sets when there is normal drive through one planetary gearing set and a back-drive through the other. The failure detection mechanism includes structure operable when a failure is sensed to either prevent further drive through the geared rotary actuator, or to activate mechanism to signal a pilot of an airplane that the failure has occurred.

Abstract: A multiple displacement motor driven power drive unit having two separate hydraulic systems each with a variable displacement hydraulic motor having its output connected to a torque summing gear train. A control provides for operation of one or the other of the motors at full displacement while the other motor is at zero displacement and free-wheels. There is a manual mechanical control operation with both motors simultaneously set at one-half of full displacement and driving the torque summing gear train. The change in motor displacements to one-half full displacement accomplishes velocity summing within the hydraulics. The multiple displacement motor driven power drive unit accomplishes the power efficiency of a multiple motor driven power drive unit utilizing a speed summing gear train with fixed displacement motors, but without the complexities associated with the use of a speed summing gear train and brakes.

Abstract: The invention relates to an electro-hydraulic control system for a power drive unit having a wobbler controlled variable displacement hydraulic motor wherein the electro-hydraulic control system causes the displacement of the hydraulic motor to match a load to be driven by a power drive unit output shaft coupled to the motor. The system results in the hydraulic motor displacement matching the load as a combined function of the input command signal, the actual wobbler position, as well as the velocity and position of the power drive unit output shaft.