Patent Application
20150240827
This invention generally relates actuators typically employed in engine environments, and more particularly to turbine engines incorporating variable stator vanes, and even more particularly to actuators for variable stator vanes.
Contemporary gas turbine engines incorporate an axial compressor section that is comprised of a plurality of airfoil sections, i.e. vanes, extending radially outwardly from a central axis of the gas turbine engine in a circular pattern, and rotatable about the central axis. Multiple circular patterns of rotor vanes are typically arranged sequentially in rows along the central axis. Between adjacent rows of rotor vanes there is also typically a set of vanes, also arranged in a circular pattern and extending radially relative to the central axis of the engine, differing from the rotor vanes in that these vanes do not rotate about the central axis of the turbine engine. These non-rotating vanes are commonly referred to as stator vanes, and each row thereof is commonly referred to as a stage. It is known to incorporate a plurality of rows of rotor vanes, as well as a plurality of rows of stator vanes, in an alternating pattern.
It is known to adjust the orientation of each stator vane about its central, radially extending, longitudinal axis to vary the angle of attack these stator vanes present to air flowing axially along the central axis of the engine and from the upstream rotating set of rotor vanes using an actuator. These variable stator vanes allow for the turbine engine to achieve air flow pressure characteristics for optimal operation in various modes of operation.
Various actuator configurations are known for achieving the aforementioned variable stator vane actuation. Each row of stator vanes, and particularly each vane thereof, is typically connected to a unison ring that is accessible from an exterior of a housing containing the rotor and stator vane rows. Rotation of this unison ring about the central axis of the engine results in the above described stator vane actuation. Each row of stator vanes has its own unison ring. A typical variable stator vane actuator thus manipulates multiple unison rings to govern the orientation of the variable stator vanes of each row of stator vanes. Examples of such actuators may be seen from inspection of U.S. Pat. Nos. 4,755,104, 5,549,448, 6,769,868, and 8,435,000, the entire teachings and disclosures of which are incorporated herein by reference thereto.
A common thread of such actuators, unfortunately, is that they are relatively complex in their construction, relatively large in size and weight, present a significant amount of wear points, and have high reactive loads. Indeed, U.S. Pat. No. 5,549,448 illustrates a conventional bell-crank style actuation arrangement. Such configurations are typically actuated by a linear actuator that is arranged and operates parallel to the central axis of the engine. This style is generally compact given the parallel arrangement of the linear actuator; however, it is also quite complex in its linkage arrangement as it requires multiple individual bell-crank mechanisms driven by a common master bell-crank mechanism, each of which presents a wear point and possible point of failure.
As another example, U.S. Pat. No. 8,435,000 illustrates a more contemporary torque-tube style actuation arrangement, wherein a rotary actuator, typically referred to as a torque tube, is arranged parallel to the central axis of the engine. A plurality of linkage arms extend from the torque tube and are connected respectively to each unison ring. An actuator acts upon the torque tube to rotate the same about its central axis to ultimately rotate the unison rings to achieve a desired stator vane orientation. This style is generally less complex than the bell-crank configuration described above. However, this configuration also utilizes a linear actuator that is arranged transverse to the central axis of the engine, and thus results in an undesirably large footprint within the engine space.
As such, there is a need in the art for a rotary actuator that has a reduced complexity, part count, number of wear points, and size.
The invention provides such a variable stator vane actuator. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.
In one aspect, the invention provides a rotary actuator with a reduced overall space footprint for actuating the variable stator vanes of a compressor section of a turbine engine. An embodiment of the rotary actuator includes a stator assembly centered along a longitudinal axis of the rotary actuator. The rotary actuator also includes a rotor assembly surrounding the stator assembly. The rotor assembly is rotatable about the longitudinal axis relative to the stator assembly. The rotary actuator also includes first and second bearing assemblies mounted at adjacent opposed axial ends of the stator assembly and connected between the stator assembly and rotor assembly to allow for the rotation of the rotor assembly about the longitudinal axis relative to the stator assembly. A hydraulic actuation arrangement is formed between the rotor assembly and the stator assembly. The hydraulic actuation arrangement includes at least one first pressure chamber and at least one second pressure chamber. The at least one first pressure chamber is operable to receive a hydraulic fluid at a first pressure. The at least one second pressure chamber is operable to receive a hydraulic fluid at a second pressure different than the first pressure to create a pressure differential between the at least one first and second pressure chambers to rotate the rotor assembly about the longitudinal axis.
In another aspect, the invention provides a rotary actuator with a reduced parts count and complexity for actuating the variable stator vanes of a compressor section of a turbine engine. The rotary actuator includes a stator assembly centered along a longitudinal axis of the rotary actuator. The rotary actuator also includes a rotor assembly surrounding the stator assembly. The rotor assembly is rotatable about the longitudinal axis relative to the stator assembly. The rotary actuator also includes first and second bearing assemblies mounted at adjacent opposed axial ends of the stator assembly and connected between the stator assembly and rotor assembly to allow for the rotation of the rotor assembly about the longitudinal axis relative to the stator assembly. A hydraulic actuation arrangement is formed between the rotor assembly and the stator assembly. The hydraulic actuation arrangement includes at least one first pressure chamber and at least one second pressure chamber. At least one of the at least one first pressure chamber and the at least one second pressure chamber has a variable volume.
In certain embodiments according to the foregoing aspects, the rotary actuator includes an inlet manifold. The inlet manifold has a first inlet and a second inlet. The stator assembly includes an internal cavity defining a first inlet chamber and a second inlet chamber. The first inlet chamber is in fluid communication with the first inlet. The second inlet chamber is in fluid communication with the second inlet. An inlet tube extends from the first inlet and fluidly seals the first inlet chamber from the second inlet chamber. The first inlet chamber includes at least one inlet port fluidly communicating the first inlet with the least one first pressure chamber. The second inlet chamber includes at least one inlet port fluidly communicating the second inlet with the at least one second pressure chamber.
In certain embodiments according to the foregoing aspects, the hydraulic actuation arrangement includes at least one stator vane extending radially outward from a center of the stator assembly, and at least one rotor vane extending radially inward from an interior hollow surface of an outer housing of the rotor assembly. The at least one stator vane sealingly engages the interior surface of the rotor housing. The at least one rotor vane sealingly engages an exterior surface of the stator assembly. The at least one first pressure chamber is formed on a first side of the at least one stator vane. The at least one second pressure chamber is formed on a second side of the at least one stator vane.
In certain embodiments according to the foregoing aspects, the hydraulic actuation arrangement includes a core member defining the at least one second pressure chamber and wherein the at least one first pressure chamber is formed between an exterior surface of the core member, and an interior surface of an outer housing of the rotor assembly. The hydraulic actuation arrangement includes at least one piston slidably received within the at least one second pressure chamber. The at least one second pressure chamber includes a seal for sealingly engaging the piston to fluidly seal the at least one second pressure chamber from the at least one first pressure chamber.
In certain embodiments according to the foregoing aspects, the hydraulic actuation arrangement includes a piston element centered along the longitudinal axis and surrounding the stator assembly. The piston element includes a seal therein that radially seals against an interior surface of an outer housing of the rotor assembly, and radially seals against an exterior surface of the stator assembly. The at least one first pressure chamber is formed on one side of the seal. The at least one second pressure chamber is formed on another side of the seal. A portion of the piston element has interior and exterior threads. A portion of the exterior of the stator assembly has threads. A portion of the interior of the outer housing of the rotor assembly has threads. The interior threads threadably engage the threads of the stator assembly. The exterior threads threadably engage the threads of the outer housing of the rotor assembly such that the piston element is linearly and rotationally movable along the longitudinal axis relative to the stator assembly.
The rotary actuator may also include at least one connection element formed on an exterior of the rotor assembly. The at least one connection element is configured to connect the rotor assembly to a unison ring of the compressor section of the turbine engine.
In yet another aspect, the invention provides a method of actuating the unison rings of a compressor section of a turbine engine using a rotary actuator. The method includes a step of supplying fluid at a first pressure to at least one pressure chamber of a hydraulic actuation arrangement of the rotary actuator. The method also includes a step of supplying fluid at a second pressure to at least one second pressure chamber of the hydraulic actuation arrangement of the rotary actuator. The steps of supplying the fluid at first and second pressures creates a force imbalance acting upon the hydraulic actuation arrangement to rotate a rotor assembly of the hydraulic actuation arrangement relative to a stator assembly about a longitudinal axis of the rotary actuator.
Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
Turning now to the drawings, several embodiments of a rotary actuator according to the teachings of the present invention are illustrated therein. As will be understood from the following, the rotary actuator according to the invention herein overcomes existing problems in the art of torque tube style rotary actuators in that it does not require a separate exterior actuator to provide its actuating force. Instead, it utilizes a hydraulic actuation arrangement formed internally therein for rotating a rotor arrangement thereof relative to a stator arrangement thereof ultimately to govern the position of one or more unison rings of a compressor section of a turbine engine. As a result, the invention provides an improvement over other rotary actuators in that it presents a reduction of parts with a retention of function, and also presents a lower cost, smaller footprint, less complex system for actuating one or more unison rings.
With specific reference to
A plurality of connection elements 104 of rotary actuator 100 are connected by linkages to a plurality of unison rings 106 mounted proximal an exterior of compressor housing 102. As is well known in the art, unison rings 106 are respectively mounted to arrays of rotary stator vanes, and are rotatable to govern the position of arrays of these rotary stator vanes which are connected thereto. The unison rings 106 are shown generally schematically, and their connection to the arrays of rotary stator vanes has been omitted for purposes of clarity. Also for purposes of clarity, the additional arrays of rotary stator vanes themselves are not illustrated, and in any event, are in no way limiting on the invention herein. Further, the particular number and angular orientation about axis 118 of connection elements 104 may vary depending upon application. Yet further, it will also be recognized that multiple actuators 100 may be arranged on single compressor section where there is a significant number unison rings 106 to actuate. It will be recognized that the foregoing variations apply equally well to actuators 200, 300 described below.
Rotary actuator 100 is operably connected to a hydraulic supply 108. Hydraulic supply 108 provides the appropriate hydraulic pressure to actuate rotary actuator 100 as described herein. Indeed, the hydraulic pressure provided by hydraulic supply 108 is operable to rotate the rotor arrangement of rotary actuator 100 in first and second rotational directions 110, 112 as illustrated. Hydraulic supply 108 may be a stand-alone hydraulic system, or a sub-module of an existing hydraulic system, such as a fuel supply system as one example. Further, hydraulic supply 108 may be integrated directly with the actuator, for example by way of an integrated Electro-Hydraulic Servo Valve (EHSV). Rotation in first rotational direction 110 results in a corresponding rotation of unison rings 106 in direction 116. Likewise, rotation of the rotor arrangement in second rotational direction 112 results in a rotation of unison rings 106 in direction 114.
Turning to
Inlet manifold 124 is mounted at one axial end of rotor assembly 100. As can be seen from the cross-section in
Second inlet 128 communicates with at least one second inlet port, and in the illustrated embodiment, a plurality of second inlet ports 136 (see
A pair of bearing cap assemblies 140, 142 are mounted at opposed axial end portions of rotary actuator 100. Each bearing cap assembly 140, 142 includes an outer rotatable member 144, 146 which is rigidly connected to rotor assembly 122 such that they are each rotatable therewith. Each bearing cap assembly 140, 142 also includes an internal bearing element 148, 150 formed between an outer wall of stator assembly 120 and an inner wall of outer rotatable members 144, 146 as shown. Each bearing cap assembly 140, 142 also includes seals 152, 154 positioned between the outer wall of stator assembly 120 and an interior wall of outer rotatable members 144, 146. Seals 152, 154 prevent leakage from the hydraulic actuation arrangement formed between stator assembly 120 and rotor assembly 122.
A pair of bracket members 156, 158 are exposed axially beyond each of bearing cap assemblies 142, 144. Bracket members 156, 158 are rigidly connected to stator assembly 120, and are operable to mount rotary actuator 100 to a compressor section of a turbine engine as generally illustrated at
A rotational position sensor 160 is formed between stator assembly 120 and rotor assembly 122. Rotational position sensor 160 is operable to detect and provide an associated signal with respect to the angular position of rotor assembly 122 relative to stator assembly 120. Although not illustrated, it will be immediately recognized that rotational position sensor 160 may be connected to a controller which provides the appropriate modulation of the hydraulic pressures provided at inlets 126, 128 to govern the angular position of rotor assembly 122 relative to stator assembly 120, ultimately to govern the position of unison rings 106 shown in
Turning now to
Stator assembly 120 is generally cross-shaped and includes a plurality of stator vanes 176 which project therefrom to make contact with interior surface 174 of outer housing 170. These stator vanes 176 are shown at the 12 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock angular positions relative to longitudinal axis 118 (See
The above introduced plurality of first and second pressure chambers 180, 182 are formed between the rotor and stator vanes 172, 176. More specifically, one of the first pressure chambers is formed on one side of each stator vane, while the second pressure chamber 182 is formed on the other side of each stator vane 176. A plurality of rotor seals 184, and stator seals 186 are mounted on each of rotor vanes 172 and stator vanes 176 so as to fluidically seal each first pressure chamber 180 from each second pressure chamber 182.
Still referring to
Similarly, and turning now to
Turning now to
Accordingly, movement into the orientation shown at
Turning now to
With brief reference back to
Turning now to
Rotary actuator 200 includes bearing cap assemblies 240, 242 which are identical in function and structure as that described above relative to bearing cap assemblies 140, 142, with one exception relative to bearing cap assembly 240 discussed below. Likewise, rotary actuator 200 employs bracket members 256, 258 which are identical in the function and structure as that described above relative to bracket members 156, 158. Rotary actuator 200 also includes a manifold 224 which is fluidly coupled to a hydraulic supply 208. Manifold 224 is also identical in function and structure as that described above relative to manifold 124. The same holds true for hydraulic supply 208 relative to hydraulic supply 108.
With the above-described similarity established, a structural description will be provided for the particular actuation arrangement of rotary actuator 200. With particular reference now to
More specifically, and still referring to
Also as shown in
More specifically, and turning now to
As stated above, stator assembly 220 includes a plurality of pistons 276 which are pivotally mounted thereto and received in second pressure chambers 282. Second pressure chambers 282 are sealed with respect to pistons 276 by way of core member seals 286 as shown.
First pressure chamber 280 is formed generally around an exterior of stator assembly 220 and core member 272. This first pressure chamber 280 is continuous, however, segregation of this first pressure chamber to create multiple first pressure chambers 280 is entirely contemplated herein. As discussed above, first pressure chamber 280 receives pressurized fluid from hydraulic supply 208 via first inlet 226, inlet tube 230, and first inlet ports 232. Second pressure chambers 282 receive pressurized fluid from second inlet 228 via second inlet ports 236, and cross passages 284 as described above. In the same manner as that described relative to rotary actuator 100, hydraulic supply 208 is operable to supply pressurized fuel at a first pressure to first pressure chambers 280, and pressurized fluid to second pressure chambers 282 at a second pressure which is different than the first pressure. As a result, there is a pressure imbalance and thus a resultant force imbalance between first and second pressure chambers 280, 282 which will ultimately cause core member 272 thus the remainder of rotor assembly 222 in one of first and second rotational directions 210, 212 as shown in
As such, the hydraulic actuation arrangement of rotary actuator 200 formed by way of first and second pressure chambers 280, 282 overcomes existing rotary actuators by not requiring an external actuator to provide the force required to rotate rotor assembly 222. It will be recognized that although a number of pressure chambers 282 and corresponding pistons 276 have been described, rotary actuator 200 could perform equally well with only a single second pressure chamber 282 and associated piston 276, or a greater number of second pressure chambers 282 and associated pistons 276 than that shown. As such, the particular number of second pressure chambers 282 should be taken by way of example only.
The effect of the above-described pressure differential is shown in greater detail in
Turning now to
Turning now to
Rotor actuator 300 includes first and second bearing cap assemblies 340, 342 which are substantially the same in their function and structure but for the exceptions discussed in the following. Likewise, rotary actuator 300 incorporates bracket members 356, 358 which are substantially the same in their structure and function as those discussed above. Bracket members 356, 358 mount rotary actuator 300 to a compressor housing of a compressor section of a turbine engine as discussed above relative to
Turning now to
Second inlet 328 fluidly communicate fluid provided by hydraulic supply 308 with at least one second inlet port, and in the illustrated embodiment, a plurality of second inlet ports 336 formed in a second inlet chamber 338 of rotor assembly 320. This plurality of second inlet ports provides pressurized fuel from second inlet 328 to a second pressure chamber 382 which also has a variable volume as described in the following. It should be noted that in the configuration shown in
These first and second pressure chambers 380, 382 are formed on opposing sides of a piston element 372 of rotor assembly 322. A piston seal 384 fluidly seals first pressure chamber 380 from second pressure chamber 382. A plurality of helical threads 376 are formed on an exterior portion of stator assembly 320. A plurality of helical threads 386 are formed on an interior portion of a rotor housing 370 of rotor assembly 322. Piston element 372 includes interior and exterior threads 374, 378 formed thereon which respectively mesh with threads 376, 386. As will be discussed in greater detail below, as the pressure increases in second pressure chamber 382, piston element 372 will linearly move from right to left relative to
The threaded engagement between piston element 372, stator assembly 320, and rotor housing 370 of rotor assembly 322 is a splined arrangement such that the revolution ratio between piston assembly 372 and rotor housing 370 is 1:2. In other words, rotor housing 370 will rotate twice as much relative to axis 318 as piston element 372. Those skilled in the art will immediately recognize that other ratios are entirely possible depending on particular configuration of the threads discussed above.
The above-described rotation of rotor housing 370 is detected by a sensor 360 which is identical to the sensors discussed above. This information is fed to a controller for control of actuator 300.
Turning now to
As a result, the angular orientation of connection elements 304 relative to axis 318 has changed to ultimately rotate the unison rings of the compressor section discussed above. In the same manner as described above, hydraulic supply 308 is operable to modulate the pressures in first and second pressure chambers 380, 382 to govern the position of piston member 372. Also in a like manner as discussed above, it will be recognized that appropriate cross passages are formed through bearing cap assembly 340 so as to fluidly communicate second pressure chamber 382 with second inlet ports 336 via annular passage 390. Accordingly, the hydraulic actuation arrangement formed by first and second pressure chambers 380, 382 of rotary actuator 300 advantageously provides the actuating force to rotationally actuate rotary actuator 300 unlike prior designs which require an exterior actuator to provide the actuating force.
While those skilled in the art will immediately discern the method of operating the embodiments of the rotary actuator described herein from the structural description provided above, the following provides an exemplary embodiment of a method of operating the rotary actuator. The following description utilizes rotary actuator 100 for purposes of explanation, although it will be recognized that the method described in the following applies equally well to rotary actuators 200, 300.
Referring back to
As described herein, embodiments of the rotary actuator according to the invention overcome existing problems in the art with torque-tube style rotary actuators by entirely eliminating the need for an external actuator to provide a force to rotate the actuator. Instead, this actuation force is provided by way of the inventive hydraulic actuation arrangement formed between the stator and rotor assemblies.
All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
