Servovalve employing a rotatable feedback linkage
AssigneeSargent Controls & Aerospace/Dover Diversified Inc.
InventorStephen B. Currey
Life of this patent
Estimating the term…
Abstract
The invention is a mechanical-type position-sensing and feedback system employed between a main stage spool valve and a pilot stage spool valve of an electro-hydraulic servovalve. The feedback mechanism makes use of a rotatable feedback link that directly senses the position of the slide of the main stage valve and transforms a linear motion of the slide into a linear movement of the sleeve of the pilot stage valve. The feedback link has an elongated body and is adapted for rotation about its body's longitudinal axis.
Claims19
An electro-hydraulic servovalve comprising:
- a main stage that includes a valve having a slide translatable within a complementary ported sleeve, wherein said valve controls delivery of pressurized fluid from a fluid supply to a load dependent on the location of the slide within the sleeve;
- a pilot stage that includes a valve having a slide translatable within a translatable ported sleeve, and wherein said pilot stage is hydraulically connected to the main stage in a manner whereby movement of the pilot stage slide is capable of causing the main stage slide to translate within its associated sleeve;
- an actuator that is operatively connected to and can affect the pilot stage valve;
- and
- a feedback mechanism that is operatively connected to the main stage valve and to the pilot stage valve and functions to cause a change in the pilot stage valve in response to movement of the main stage slide and wherein said feedback mechanism includes a rotatable feedback link having an elongated body portion that has a longitudinal axis, and wherein said feedback link has a first end portion engaged to the main stage slide and a second end portion engaged to the pilot stage sleeve and wherein when said main stage slide translates within its associated sleeve, the feedback link rotates about said longitudinal axis and causes a translation of the pilot stage sleeve.
An improved servovalve of the type having a main stage valve in the form of a spool valve, a pilot stage valve in the form of a spool valve, and an actuator that acts on the pilot stage valve, wherein the improvement comprises:
- a feedback mechanism operatively connected to the main stage valve and to the pilot stage valve and functioning to cause a change in the pilot stage valve in response to movement of a slide of the main stage valve and wherein said feedback mechanism includes a rotatable feedback link that has an elongated body having a longitudinal axis, wherein said feedback link has a first end portion engaged to the slide of the main stage valve and a second end portion engaged to a movable sleeve of the pilot stage valve, and wherein when the slide of the main stage valve translates within an associated sleeve, the feedback link rotates about said longitudinal axis and causes a translation of the sleeve of the pilot stage valve, and wherein translation of the sleeve of the pilot stage valve affects fluid flow to the main stage valve.
Dependencies are inferred from the claim text.