Servovalve

专利名称：Servovalve发明人：Herbert Lembke申请号：US06/693756申请日：19850124公开号：US04624284A公开日：19861125

摘要：A servovalve includes a flow-control valve connectable between a source offluid pressure and a load and having a spool displaceable between an open positionpermitting fluid flow between the load and the source and a closed position axially offsettherefrom and blocking such flow. A pilot valve has an impact plate and a pair of nozzlesoperatively axially oppositely effective on the spool and oppositely flanking the plate.Thus when the plate is closer to one of the nozzles than to the other the spool is axiallydisplaced into one of its positions and when the plate is closer to the other nozzle thespool is urged axially oppositely. A solenoid-type servomotor is connected to the impactplate to move same between the nozzles so that when it is close to one nozzle it blocksflow therefrom and allows pressure to build up on the corresponding end of the spool,while the other nozzle is opened to reduce pressure at the corresponding spool end. Afeedback spring is attached to the impact plate, extends generally radially of the spool,and has a free end projecting into a recess formed in the spool. A force- transmitting ballis fixed to the free end of the spring and fitted in the recess and has an outer surfaceengageable with the inner surface of the recess. The outer surface of the ball is ofcorundum and the inner surface of the bore is of steel or vice versa.

申请人：MANNESMANN REXROTH GMBH

代理人：Andrew Wilford

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