Vickers, Inc.

Albert Blatter

Robert E Davis

Richard Scott Leemhuis

Melvin A Rode

James A Kessler

Gene Y Wen

Ronald E Chipp

Jeffrey P Cherry

John A Miller

An electrohydraulic servovalve comprising a torque motor which receives an electrical signal and positions a flapper between a pair of opposed nozzles to control a spool valve and a feedback spring connected to the flapper and to the spool of the spool valve. The flapper is connected to an armature of the torque motor. The joint between the armature and the flapper comprises a one part, heat cured thermosetting adhesive.

Power transmission

An electrohydraulic servovalve comprising a torque motor which receives an electrical signal and position a flapper of a spring tube and flapper subassembly between a pair of opposed nozzles to control a spool valve and includes a feedback spring connected to the flapper and to the spool of the spool valve. A method of obtaining torque motor air gap symmetry is provided which comprises forming the pole piece/magnet subassembly to provide a desired total pole air gap on both ends of the armature, forming the armature ends so that they are equal to the total pole gap minus twice the desired nominal air gap, assembling the torque motor before attaching the spring tube and flapper subassembly, positioning the spring tube and flapper subassembly and the pole piece/magnets in a relative position to one another, providing spacers between the lower edges of the armature and the gap of the pole pieces, providing wedges between the upper surfaces of the ends of the armatures and the gap of the upper pole piece, providing a joint between the tube and the armature by a hardenable material to bond the armature and the spring tube, and permitting the joint to harden and set.

An electrohydraulic system includes a plurality of electrohydraulic devices individually controlled by on-board microprocessor-based control electronics. Each individual device controller is connected to and addressable by a master controller for coordinating operation of the various devices. An electrohydraulic servo valve assembly includes a hydraulic manifold having a valve spool variably positionable therein under control of a torque motor. A microprocessor-based controller is connected to the torque motor and is mounted on the manifold by a cover which encloses and protects both the controller and the torque motor. A watchdog timer in the microprocessor-based controller monitors pulsewidth modulated signals to the torque motor for terminating operation in the event of signal loss. In a preferred embodiment of the invention, the servo valve assembly is coupled to a linear actuator which has its position monitored by an electroacoustic transducer. Improved electronics couple the transducer to the control microprocessor.

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Highland, MI, United States of America

Albert Blatter