Hr Textron, Inc.

Other

Woodward Hrt, Inc.

Stephen J Tranovich

James L Coakley

Kumaraguru Poonamalli Palani

A torque motor has a mechanical reference member, an armature, and a field assembly. The field assembly includes field pole pieces defining a pole opening, and the armature is mounted to the mechanical reference member for rotation about a motor axis and extends into the pole opening with respective gaps to the field pole pieces. The field assembly is secured to the mechanical reference member and spaced therefrom by elastically deformable flexures, deformed sufficiently to locate the armature at a predetermined position within the pole openings with corresponding lengths of the gaps. During manufacture, a load can be applied to move the field assembly relative to the mechanical reference member against the deformation force of the flexures to locate the pole opening relative to the armature pole piece such that the gaps of desired lengths are formed.

Torque motor with mechanical flexures establishing armature-to-field gaps

A control system is provided for a limited angle torque motor used as a rotary position control device. A motor for which the system is intended would consist of a rotor and a stator. The system uses an analog Hall-effect sensor to sense the position of the rotor. Rather than attempting to shield the Hall-effect sensor from the influences of magnetic fields generated by the field windings in the stator during motor operation, the system allows the output signal from the Hall effect sensor to contain elements of both the angular position and the extraneous magnetic field generated by the field windings of the motor. Current feedback from a circuit which independently senses the motor current is then combined with this signal to eliminate the influence of the motor coil magnetic field. The system is applicable to a number of limited angle torque motor designs. A preferred embodiment is shown wherein a unique sandwich construction of the rotor magnets on a soft iron rotor core provides a highly linear angular position signal for the system to process. Furthermore, a means of fixturing the Hall-effect sensor within the motor end windings to facilitate the position sensing for the preferred embodiment is described. Finally, a detailed description of the electronic circuit used to implement the system in the preferred embodiment is provided, and a number of alternate analog and digital implementations of the circuit are discussed.

Method of controlling rotary position of a torque motor

A rotary servovalve having a cylindrical spool (18), which rotates through a limited angle, positioned within a housing (16). The spool and housing have transverse holes through both parts with matching position and diameter. The holes in the housing form cylinder ports (21) and (24) for connection to a load. A metering pin (22) is fixed in the opening in the spool and its end surfaces conform to the surface of the spool. These end surfaces block the opposed load ports (21) and (24) when the valve is in the null position. Fluid under pressure and exhaust are applied through the inlet port (20) and return (11) ports to circumferential grooves (23) and (25) on opposite sides of the metering pin, which are narrower than the diameter of the pin. When the spool is rotated, pressure is connected to one of the load ports and return to the opposite port and the resulting flow is proportional to the angle of rotation. The valve is manufactured by positioning the spool, with the groove pre-formed, at the desired point in the housing and clamping them together. A hole is then bored simultaneously through both parts. The metering pin is then sized, inserted into the spool, fixed in place, and its ends are ground to conform to the clindrical surfaces of the spool and the housing.

Rotary metering-pin servovalve and method of manufacturing the same

An integrated compliance electrohydraulic servovalve system connected to a load such as a simulated living being to provide more realistic movement thereto. The system includes a pressure transducer for sensing the pressure appearing at the output of the electrohydraulic servovalve and which is applied to an actuator connected to the load. The pressure as sensed is developed into a corresponding electrical signal which is used as a feed back signal to the drive motor of the electrohydraulic servovalve. The actuator position signal is also provided and is summed with the position command input signal to provide the command signal which is also summed with the pressure signal prior to application to the drive motor. The utilization of the pressure feed back signal provides compliance to the over all system resulting in a realistic movement of the simulated living being.

Integrated compliance servovalve

A control valve including a second stage spool for controlling flow of fluid from a source thereof to a load. The valve includes one additional pressure slot and one additional return slot on each side thereof and separated by a land on the spool from the usual pressure and return slots respectively. Each of the spool lands separating the pressure and return slots defines and opening therethrough to interconnect the slots so that upon movement of the spool to connect the source to the load, a greater flow of fluid is provided and would be possible with the same size spool without the additional pressure and return slots.

High flow control valve

A method of manufacturing a moving coil force motor particularly adapted for utilization with a hydraulic servovalve. The method includes aligning a flexure spring with respect to the permanent magnet structure and thereafter securing the permanent magnet structure and flexure spring within a case for the force motor. Subsequently, the coil structure is aligned with respect to the gap provided in the permanent magnet pole pieces by relatively moving the motorcase with respect to the coil until the appropriate position is attained and thereafter securing the case against further movements.

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Valencia, CA, United States of America

Stephen J Tranovich