Rotary servovalve

A rotary servovalve comprising:

• (a) a valve sleeve having a plurality of sleeve lands on an inner peripheral surface;
• (b) a rotor having a plurality of rotor lands on an outer peripheral surface and relatively rotatably fitted in said valve sleeve;
• (c) first and second fluid supply inlets opening into a space between said valve sleeve and said rotor;
• (d) a plurality of fluid discharge outlets opening in said space;
• (e) a pressure control section composed of selected ones of said sleeve lands and said rotor lands, said selected sleeve and rotor lands being angularly spaceable from each other when the rotary servovalve is in a neutral condition to allow communication between said first fluid supply inlet and at least a first one of said fluid discharge outlets;
• (f) a pressure characteristic adjusting section composed of other selected ones of said sleeve lands and said rotor lands, said other selected sleeve and rotor lands being positionable in overlapping relation to each other when the rotary servovalve is in the neutral condition to prevent communication between said second fluid supply inlet and said at least a first one of said fluid discharge outlets;
• (g) first chamfers formed on at least one of the sleeve and rotor lands constituting said pressure control section, said first chamfers comprising means for gradually reducing the area of communication between said first fluid supply inlet and said first one of said fluid discharge outlets when said valve sleeve and said rotor are relatively rotated;
• (h) second chamfers formed on at least one of the sleeve and rotor lands constituting said pressure characteristic adjusting section, said second chamfers comprising means for gradually increasing the area of communication between said second fluid supply inlet and said first one of said fluid discharge outlets when said valve sleeve and said rotor are relatively rotated;
• and
• (i) third chamfers formed on at least one of the sleeve and rotor lands constituting said pressure characteristic adjusting section, said third chamfers comprising means for gradually reducing the area of communication between said second fluid supply inlet and said first one of said fluid discharge outlets, with a delay from the action of said second chamfers, when said valve sleeve and said rotor are relatively rotated.