1. Technical Field
The disclosure generally relates to gas turbine engines.
2. Description of the Related Art
Many gas turbine engines incorporate variable stator vanes, the angle of attack of which can be adjusted. Conventionally, implementation of variable vanes involves providing an annular array of vanes, with each of the vanes being attached to a spindle. The spindles extend radially outward through holes formed in the engine casing in which the vanes are mounted. Each of the spindles is connected to a lever arm that engages a unison ring located outside the engine casing. In operation, movement of the unison ring pivots the lever arms, thereby rotating the spindles and vanes.
Gas turbine engine systems involving gear-driven variable vanes are provided. In this regard, an exemplary embodiment of a gas turbine engine system comprises: a ring gear assembly operative to be mounted within an engine casing; and a vane module having a first vane airfoil and a first gear, the first gear being operative to engage the ring gear assembly such that movement of the ring gear alters a position of the first vane airfoil.
An exemplary embodiment of a gas turbine engine comprises: a compressor; a combustion section operative to receive compressed air from the compressor; a turbine operative to drive the compressor; a casing operative to encase the turbine; and a gear-driven variable vane system having a ring gear assembly and a vane module, the ring gear assembly being mounted within an interior of the casing, the vane module having a first vane airfoil and a first gear, the first gear being operative to engage the ring gear assembly such that movement of the ring gear alters a position of the first vane airfoil.
An exemplary embodiment of a vane module for a gas turbine engine comprises: an inner platform, an outer platform, a first vane airfoil and a first gear, the first vane airfoil extending between the inner platform and the outer platform, the vane module being operative to rotate the first vane airfoil relative to the inner platform and the outer platform, responsive to rotation of the first gear.
Other systems, methods, features and/or advantages of this disclosure will be or may become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features and/or advantages be included within this description and be within the scope of the present disclosure.
Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Gas turbine engine systems involving gear-driven variable vanes are provided, several exemplary embodiments of which will be described in detail. In some embodiments, the vanes are incorporated into rotatable vane modules. Gears of the vane modules are engaged between opposing gear teeth of annular ring gears that are positioned within the engine casing.
As shown in the partially cut-away, schematic diagram of
Each vane module engages a ring gear assembly 130. Notably, the ring gear assembly is positioned within the engine casing. A motor assembly 140 also is provided that includes a motor 142 (positioned outside the engine casing), a shaft 144 and a drive gear 146. In the embodiment of
Shaft 144 extends from the motor into the interior of the engine casing via a penetration 148. A distal end of the shaft is attached to drive gear 146, which engages the ring gear assembly so that operation of the motor rotates the drive gear, thereby actuating the ring gear assembly. Actuation of the ring gear assembly rotates the module gears, thereby positioning the vanes.
Another embodiment is depicted schematically in
Vane module 202 also includes a spindle 218 that extends radially outwardly from the outer platform. In this embodiment, the spindle includes a spindle feature 220 (e.g., an annular recess) that mates with a corresponding feature 222 (e.g., a ridge) of the mounting assembly. The spindle supports the first vane module gear 224 that extends into a track 226 of the mounting assembly.
In this regard, mounting assembly 204 is provided in a split-ring configuration that includes a forward annular member 230 and an aft annular member 232. The annular members include split apertures that engage about the vane module spindles. For instance, member 230 includes a split aperture 234 and member 232 includes a split aperture 236 that engage each other to form an aperture in which a spindle is received. As another example, spindle 218 is received by split aperture 238 of member 232 and a corresponding split aperture of member 230 (not shown).
The mounting assembly also includes outwardly extending tabs (e.g., tab 244) that facilitate attachment of the mounting assembly to the interior of an engine casing. So mounted, the engine casing, the tabs and respective outer surfaces 246, 248 of the annular members 230, 232 form track 226 within which the opposing ring gears 250, 252 of the ring gear assembly 206 are located.
Additionally, the vane outer platform 212 has a mating feature 254 that is in close contact with the mating surface 256 on the split ring member 232 to prevent the vane module 202 from rotating relative to the split ring mounting assembly 204. The mounting assembly 204 is located within the case 101 such that the axial and tangential loads created during the operation of the engine are transmitted from the vane module 202, through the spindle feature 220, into the mount assembly 204. The mount assembly 204 can move radially relative to the case 101 so that thermally induced loads are not transmitted into the case 101.
The mounting assembly 204, supports the vane modules 202 in the radial direction by the restraint of the outer platform 212 through interaction between spindle feature 220 and feature 238. In this embodiment, the radial growth of the inner platform 210 is not constrained by the mount assembly 204, thus avoiding adverse loading. The inner platform 210 relative position to the outer platform 212 is maintained by the first vane airfoil 214 and the second vane airfoil 216.
Various techniques and/or mechanisms can be used for promoting desired engagement between the opposing ring gears. In this regard, reference is made to the schematic diagrams of
In
Notably, in this embodiment, slot 316 is longer in the circumferential direction than the protrusion 314 to allow the ring 304 to move concentrically with ring 306 about axis 121. However, slot 316 is not substantially larger in radial thickness than the protrusion 314 to prevent relative motion of the center of ring 304 and the center of ring 306. The relative difference in length between slot 316 and the protrusion 314 may be used to restrict the overall rotation of ring 304 relative to ring 306, about axis 121.
The fastener 320 is held in position by bore 322, and uses a spring feature 324 (
The spring 332 is mounted to rings 334 and 336 such that the rings are free to rotate relative to each other about axis 121. The spring 332 rotates as needed, within rings 334 and 336, and applies an increasing load, pulling the rings 334 and 336 together as the relative distance between the end points of spring 332 increase, i.e., the spring is always pulling the two rings 334 and 336 together.
In contrast to the embodiments of
The connector 384 extends through ball joint 392, and can move relative to the ball joint 392 about an axis defined by the longitudinal axis of the connector 384. A spring assembly 394, attached to the end of connector 384, applies a load to the ball joint 392. The spring pulls upon connector 384, which also applies a load on socket 380. Thus, opposing forces created by spring preload act upon socket 380 and ball joint 392, through connector 384, such that rings 374 and 376 are pulled together.
The relative rotation of rings 374 and 376, about axis 121, causes the connector 384 to rotate in the ball joint 382 in socket 380 and ball joint 392 in socket 390. The increase in distance between the center of ball joints 382 and 392 results in the compression of the spring mounted to connector 384, and a corresponding increase in the load pulling rings 374 and 376 together. Selection of the spring strength (spring rate) and the length of connector 384 will allow rotation motion of the rings 374 and 376 to occur as desired, without causing binding, or excessive loads in connector 384.
In some embodiments, the shape of the contact surface between ball joints 380, 382, 390 and 392 may be spherical, cylindrical, or a combination of the two, as desired to control the relative motion of rings 374 and 376.
It should be emphasized that the above-described embodiments are merely possible examples of implementations set forth for a clear understanding of the principles of this disclosure. Many variations and modifications may be made to the above-described embodiments without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the accompanying claims.
Number | Name | Date | Kind |
---|---|---|---|
2819732 | Paetz | Jan 1958 | A |
3352537 | Alexander | Nov 1967 | A |
4430043 | Knight et al. | Feb 1984 | A |
4979874 | Myers | Dec 1990 | A |
5277544 | Naudet | Jan 1994 | A |
5630701 | Lawer | May 1997 | A |
6039534 | Stoner et al. | Mar 2000 | A |
6435821 | Nicolson et al. | Aug 2002 | B1 |
6767183 | Schilling et al. | Jul 2004 | B2 |
6984104 | Alexander et al. | Jan 2006 | B2 |
7155222 | Jain et al. | Dec 2006 | B1 |
7223066 | Rockley | May 2007 | B2 |
20070020090 | Giaimo et al. | Jan 2007 | A1 |
Number | Date | Country |
---|---|---|
1466613 | Mar 1977 | GB |
1505858 | Mar 1978 | GB |
Number | Date | Country | |
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20090104022 A1 | Apr 2009 | US |