Patent ID: 6269838
Filing Date: 2001-08-07
Classification: F15B,F16K,Y10T

Abstract:
A rotary servovalve system comprising:a pressurized fluid supply source,a fluid reservoir having a fluid pressure lower than that of said fluid supply source,a fluid transfer valve housing having a wall of annular cross section and at least one fluid inlet port coupled to said fluid supply source, at least one fluid outlet port coupled to said fluid reservoir and located diametrically opposite said fluid inlet port and at least one first fluid control port and at least one second fluid control port located diametrically opposite each other and equidistant from said inlet and outlet ports,a movable valve member located within said valve housing and alternatively rotatable in opposite angular directions from a closed position in which flow through all of said ports is blocked to positions in which each of said first and second fluid control ports alternatively permits flow therethrough from said fluid inlet port while the other of said first and second fluid control ports concurrently permits flow therethrough to said reservoir,a rotary magnetic solenoid having an electrically activated stator and an armature with at least one permanent magnet thereon alternatively rotatable relative to said stator in opposing angular directions from a null position and said at least one permanent magnet returns said armature to said null position when said stator is deactuated, and said armature drives said movable valve member so that said movable valve member is in said closed position when said armature is in said null position,a position sensor located proximate to said rotary magnetic solenoid to provide a feedback signal indicative of the position and direction of rotation of said armature relative to said null position, anda control circuit responsive to said position sensor to provide a feedback electrical signal having an electrical frequency response bandwidth of at least about one hundred twenty hertz to said stator to move said movable valve member co a target angular orientation relative to said valve housing.