Balanced rotary servovalve

• US 6,470,913 B1
• Filed: 06/19/2000
• Issued: 10/29/2002
• Est. Priority Date: 12/22/1998
• Status: Expired due to Fees

• Current Assignee: Raymond D. Woodworth
• Original Assignee: Raymond D. Woodworth
• Inventors: Woodworth, Raymond D.
• Primary Examiner(s): RIVELL, JOHN A
• Application Number:
  US09/595,997
• Time in Patent Office: 862 Days
• Field of Search: 137/625.21, 137/625.22, 137/625.23, 137/625.24, 137/625.47, 251/283
• US Class Current: 137/625.23
• CPC Class Codes: F15B 13/0406 for rotary valves
• CPC Class Codes: F15B 2013/0409 Position sensing or feedback of the valve member
• CPC Class Codes: F16K 11/085 with cylindrical plug
• CPC Class Codes: F16K 31/041 for rotating valves F16K31/055 takes precedence
• CPC Class Codes: Y10T 137/86654 For plural lines

Abstract

A rotory servovalve is constructed with a cylindrical annular housing and a cylindrical valve element rotatable therewithin. The valve housing has at least two inlet orifices, at least two outlet orifices, at least two first fluid transfer control orifices, and at least two second fluid transfer control orifices. At least two orifices of each type are located on opposite sides of the valve housing from each other. Preferably there is a first end orifice, a central orifice, and a second end orifice of each type. The end orifices of each type are angularly and longitudinally aligned with each other and are angularly offset 180 degrees from a central orifice of the same type. The end orifices of each type have an area equal to one-half the area of the central orifice of the same type and are equally spaced in opposite longitudinal directions from the central orifice of the same type. An imbalance of fluid forces within the servovalve mechanism is thereby avoided, both in a direction perpendicular to the valve axis and in planes passing through and containing the valve axis. By eliminating force imbalances within the valve in high-pressure applications the electrical current requirement and the mass of the components required for the driving motor or rotory solenoid that operates the valve are reduced.

Claims

1. In a rotary valve including a hollow, cylindrical housing defining a longitudinal axis and having inlet and outlet ports defined therethrough and a valve core of a cylindrical configuration having transverse passageways defined therethrough and rotatably mounted within said valve housing, the improvement wherein said ports are aligned on said valve housing and said passageways are alignable with said ports by rotation of said valve core within said housing so that rotational bending moments upon said valve core produced by fluid pressure in said passageways are balanced at all times and wherein said valve housing and said valve core both have first and second ends, and said ports are comprised of a first end inlet port, a second end inlet port, a central inlet port, a first end outlet port, a second end outlet port, and a central outlet port;

and said end inlet and outlet ports are each equal in area to each other and are each half the area of each of said central ports, and said first end inlet port, said central outlet port and said second end inlet port are angularly aligned with each other and said central outlet port lies midway between said end inlet ports in a longitudinal direction, and said first end outlet port, said central inlet port and said second end outlet port are angularly aligned with each other and said central inlet port lies midway between said end outlet ports, and said first and second end inlet ports are angularly displaced 180 degrees from said first and second end outlet ports and said central inlet port is angularly displaced 180 degrees from said central outlet port.

2. A rotory valve according to claim 1 wherein said first and second end inlet ports are respectively located diametrically opposite said first and second end outlet ports.

3. A force balanced rotory valve comprising:

a hollow cylindrical valve housing having a longitudinal axis and first and second opposite ends and defining a central radial inlet port therein and a central radial outlet port therein equal in area to each other and located in axial alignment and one hundred eighty degrees in angular displacement from each other, first end and second end radial inlet ports respectively located in said first and second ends of said valve housing in angular alignment with each other and with said central outlet port and longitudinally displaced equidistantly from said central outlet port, and first end and second end radial outlet ports respectively located in said first and second ends of said valve housing in angular alignment with each other and with said central inlet port and axially displaced equidistantly from said central inlet port, and each of said first and second end inlet and outlet ports has an area half that of each of said central ports, and

a valve closure element of cylindrical configuration rotatably mounted within said valve housing and defining central, first end and second end transverse passages therethrough which are respectively longitudinally aligned with said central ports, said first end ports, and said second end ports, and said first end passageways and said second end passageways are each of a cross-sectional area one-half that of each of said central passageways, and said passageways extend in a transverse direction.

4. A valve according to claim 3 wherein said passageways are straight and parallel to each other.

5. A valve according to claim 4 wherein each of said ports has a rectangular shape and all of said ports are of equal angular width.

6. A rotory valve comprising:

a hollow cylindrical valve housing having a longitudinal axis and first and second opposite ends and defining a central inlet port and a central outlet port equal in area to each other and longitudinally aligned and angularly displaced one hundred eighty degrees from each other, a first end inlet port and a first end outlet port equal in area to each other and each equal to half the area of each of said central ports and longitudinally aligned and angularly displaced one hundred eighty degrees from each other and located in said first end of said valve housing at a longitudinal offset distance from said central ports, a second end inlet port and a second end outlet port equal in area to each other and each equal to half the area of each of said central ports and longitudinally aligned and angularly displaced one hundred eighty degrees from each other and located in said second end of said valve housing at said same longitudinal offset distance from said central ports, and

a valve core of cylindrical configuration rotatably mounted within said valve housing and having central, first end, and second end passageways defined therethrough which are respectively longitudinally aligned with said central, first end and second end ports, and said first end and second end passageways each have a cross-sectional area half that of said central passageway, and said passageways are oriented so as to provide concurrent fluid flow through said passageways through all of said ports when said valve core is rotated to an open position within said valve housing and so as to concurrently block all of said passageways when said valve core is rotated to a closed position within said valve housing.

7. A rotory valve according to claim 6 wherein all of said ports are of equal angular width and have a rectangular shape.

8. A rotory servovalve comprising:

a fluid transfer valve housing having a wall of annular cross section and a plurality of fluid inlet ports coupled to a common fluid inlet line, a plurality of fluid outlet ports coupled to a common fluid outlet line, a plurality of first fluid control ports coupled to a common first fluid control line, and a plurality of second fluid control ports coupled to a common second fluid control line, and at least two of said inlet ports are angularly displaced from each other by one hundred eighty degrees and are longitudinally offset from each other in said housing, at least two of said outlet ports are angularly displaced from each other by one hundred eighty degrees and are longitudinally offset from each other in said housing, at least two of said first fluid control ports are angularly displaced from each other by one hundred eighty degrees and are longitudinally offset from each other in said housing, and at least two of said second fluid control ports are angularly displaced from each other by one hundred eighty degrees and are longitudinally offset from each other in said housing, and said inlet and outlet ports are each angularly displaced from said control ports by ninety degrees.

9. A rotory servovalve comprising:

a valve housing of a cylindrical shape and having a valve cavity of circular cross section defined therewithin and defining at least two rectangular inlet ports to said valve cavity, and at least one of said fluid inlet ports is angularly offset one hundred eighty degrees from at least one other of said fluid inlet ports, at least two rectangular outlet ports from said valve cavity and at least one of said fluid outlet ports is angularly offset one hundred eighty degrees from at least one other of said fluid outlet ports, and at least two first rectangular fluid control ports in communication with said valve cavity and at least one of said first fluid control ports is angularly offset one hundred eighty degrees from at least one other of said first fluid control ports, and at least two second rectangular fluid control ports in communication with said valve cavity and at least one of said second control ports is angularly offset one hundred eighty degrees from one other of said second fluid control ports and said first and second fluid control ports are all angularly offset equidistantly from all of said inlet and outlet ports,

a bidirectional valve closure element having a gate portion with at least two pairs of two mutually parallel, flow directing faces of rectangular shape, and said pairs of flow directing faces are longitudinally offset from each other and are longitudinally aligned with said ports and said flow directing faces in each pair are longitudinally aligned with each other and laterally spaced from each other, whereby pairs of longitudinally offset parallel flow paths are established through said valve housing and through said gate portion of said valve closure element, and said valve closure element is located within said valve cavity and is coaxially aligned and rotatable therewithin to, in the alternative;

(1) permit concurrent fluid flow therethrough in opposite directions within each pair of mutually parallel flow paths, and (2) concurrently block all of said inlet ports and all of said outlet ports.

10. In a rotory servovalve system in which fluid is directed through an inlet port, an outlet port, a first fluid control port, and a second fluid control port in a valve housing as directed by a movable valve gate element rotatable within said housing in opposite directions of angular rotation from a position prohibiting fluid flow through any of said ports to alternative positions permitting fluid flow in alternative opposite directions through each of said first and second fluid control ports, the improvement comprising a plurality of each of said ports as aforesaid, and at least two of said inlet ports are located on opposite sides of said valve housing from each other, at least two of said outlet ports are located on opposite sides of said valve housing from each other, at least two of said first fluid control ports are located on opposite sides of said valve housing from each other, and at least two of said second fluid control ports are located on opposite sides of said valve housing from each other, and said ports are located in said valve housing such that offsetting bending forces are created on said movable valve element by fluid pressure within said valve.