Frictionless spool valve

Claim 1

In a valve, the combination of a housing having a bore therein, a conduit communicating with the bore for supplying pressurized fluid thereto, a spool, having a land integral therewith, mounted within the bore for axial movement therein, the periphery of the land having a plurality of peripherally spaced recessed surfaces respectively defining a plurality of recessed spaced around the land and a plurality of axially extending, peripherally space, relieved portions respectively defining a plurality of axially extending orifices, the orifices being respectively contiguous with the recesses at the axial ends thereof and being adapted to direct flows of pressurized fluid thereto, means to communicating with the supply conduit to supply equal pressure to the orifices, means producing flow from the recesses through clearance path means defined by the periphery of the spool and the housing and whereby displacement of the spool to an eccentric position with respect to the bore will selectively vary the pressures in the recesses to produce a differential pressure acting on the recessed surfaces which will generate a force tending to restore the spool to concentricity within the bore.