Abstract:
One embodiment of the present invention is a unique turbine engine. Another embodiment is a unique vane actuation system. In one form, the actuation system includes a four bar linkage. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for turbine engines and vane actuation systems. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Patent Application 61/291,529, filed Dec. 31, 2009, and is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to turbine engines, and, in particular, a vane actuation system for a turbine engine. 
     BACKGROUND 
     Actuation systems for variable geometry turbomachinery components, such as compressors in gas turbine engines, remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology. 
     SUMMARY 
     One embodiment of the present invention is a unique turbine engine. Another embodiment is a unique vane actuation system. In one form, the actuation system includes a four bar linkage. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for turbine engines and vane actuation systems. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
         FIG. 1  schematically depicts a gas turbine engine having a four bar linkage vane actuation system in accordance with an embodiment of the present invention. 
         FIG. 2  is a cross section of a compressor having a four bar linkage vane actuation system in accordance with an embodiment of the present invention. 
         FIG. 3  is a schematic illustration of the four bar linkage system of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the invention is intended by the illustration and description of certain embodiments of the invention. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present invention. Further, any other applications of the principles of the invention, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the invention pertains, are contemplated as being within the scope of the present invention. 
     Referring now to the drawings, and in particular,  FIG. 1 , a non-limiting example of a gas turbine engine  10  in accordance with an embodiment of the present invention is schematically depicted. In one form, gas turbine engine  10  is a turbofan engine, e.g., an aircraft propulsion power plant. In other embodiments, gas turbine engine  10  may be any gas turbine engine configuration, such as a turbojet engine, a turboprop engine, and/or a turboshaft engine. In one form, engine  10  is an axial flow engine. In other embodiments, engine  10  may have axial, centrifugal and/or axi-centrifugal compressors and/or turbines. Embodiments of the present invention include both single-spool engines and multi-spool engines. In some embodiments, engine  10  may be a steam turbine engine. 
     In one form, gas turbine engine  10  includes a compressor  12  with outlet guide vane (OGV)  14 , a diffuser  16 , a combustor  18  and a turbine  20 . Diffuser  16  and combustor  18  are fluidly disposed between OGV  14  of compressor  12  and turbine  20 . Turbine  20  is drivingly coupled to compressor  12  via a shaft  22 . 
     Compressor  12  includes a plurality of blades (not shown) and vanes for compressing air. Two stages of vanes are depicted in  FIG. 1  as a vane stage  24  having a plurality of vanes  26 , and a vane stage  28  having a plurality of vanes  30 . During the operation of gas turbine engine  10 , air is drawn into the inlet compressor  12 , and after having been compressed, is discharged via OGV  14  into diffuser  16 . Diffuser  16  reduces the velocity of the pressurized air from compressor  12 , and directs the pressurized air to combustor  18 . Fuel is mixed with the air and combusted in combustor  18 , and the hot gases exiting combustor  18  are directed into turbine  20 , which extracts some of the energy from the hot gases to generate mechanical shaft power to drive compressor  12  via shaft  22 . The hot gases exiting turbine  20  are directed into a nozzle (not shown), which provides the thrust output by gas turbine engine  10 . 
     In order to maximize the efficiency of gas turbine engine  10 , it may be desirable to vary the aerodynamic geometry of turbomachinery components of gas turbine engine  10  with changes in mass flow through the engine and/or changes thrust (power) output. For example, a variable geometry compressor may allow compressor operation closer to the compressor surge line throughout a range of engine operating speeds. Accordingly, embodiments of the present invention include a variable geometry system  32 . In one form, variable geometry system  32  is operative to selectively increase or decrease the angle of attack of compressor vanes  26  and  30 , for example, to enhance compressor  12  performance. In other embodiments, the angles of attack of other vane stages may also be controlled in addition to or in place of compressor vanes  26  and  30 . In still other embodiments, variable geometry system  32  may be operative to selectively increase or decrease the angle of attack of turbine vanes in turbine  20 . 
     Referring now to  FIG. 2  in conjunction with  FIG. 1 , variable geometry system  32  is described further. Variable geometry system  32  includes a vane actuation system  34  for changing the angle of attack of compressor vanes  26  and  30 . Vane actuation system  34  includes a unison ring  36  for vane stage  24 , a unison ring  38  for vane stage  28 , a four bar linkage system  40 , and an actuator  42 . 
     Vane stage  24  and vane stage  28  are housed in a vane case, in particular, a compressor case  44 , which in one form is a single case structure. Compressor case  44  may be formed of one ore more ring cases, e.g., one that houses both vane stage  24  and vane stage  28  or one ring case each for vane stage  24  and vane stage  28 . Compressor case  44  may alternatively be a split case, e.g., split along a gas turbine engine  10  axial line. Compressor case  44  includes a plurality of circumferentially spaced pilot openings  46  for piloting each vane  26  of vane stage  24 . Compressor case  44  also includes a plurality of circumferentially spaced pilot openings  48  for piloting vanes  30  of vane stage  28 . Disposed in each of openings  46  is a bushing  50 . Disposed in each of pilot openings  48  is a bushing  52 . 
     Each vane  26  includes a pivot shaft  54  that extends approximately radially outward from the tip of vane  26  into bushing  50 . Disposed radially inward of each vane  26  is a vane support structure  56  having a plurality of circumferentially spaced pilot openings  58 . Disposed in each pilot opening  58  is a bushing  60 . 
     Each vane  26  includes a pivot shaft  62  that extends approximately radially inward into bushing  60 . Pivot shaft  54  and pivot shaft  62 , in conjunction with bushings  50 ,  60  and pilot openings  46 ,  58  define an axis of rotation  64 . Each vane  26  is pivotable about axis of rotation  64  to increase or decrease the angle of attack of vane  26 . Bushings  50  and  60  may reduce friction and wear of pivot shaft  54 , pivot shaft  62 , and pilot openings  46  and  58 . Although the depicted embodiment includes bushings  50  and  60 , other embodiments may not include bushings. Also, it will be noted that other schemes for piloting and positioning vanes  26  within compressor case  44  may be employed in other embodiments of the present invention. 
     Each vane  30  includes a pivot shaft  66  that extends approximately radially outward from the tip of vane  30  into bushing  52 . Disposed radially inward of each vane  30  is a vane support structure  68  having a plurality of circumferentially spaced pilot openings  70 . Disposed in each pilot opening  70  is a bushing  72 . Each vane  30  includes a pivot shaft  74  that extends approximately radially inward into bushing  60 . 
     Pivot shaft  66  and pivot shaft  74 , in conjunction with bushings  52 ,  72  and pilot openings  48 ,  70  define an axis of rotation  76 . Each vane  30  is pivotable about axis of rotation  76  to increase or decrease the angle of attack of vane  30 . Bushings  52  and  72  may reduce friction and wear of pivot shaft  66 , pivot shaft  74 , and pilot openings  48  and  70 . Although the depicted embodiment includes bushings  52  and  72 , other embodiments may not include bushings. Also, it will be noted that other schemes for piloting and positioning vanes  30  within compressor case  44  may be employed in other embodiments of the present invention. 
     Four bar linkage system  40  includes a plurality of links, designated as links R 1 , R 2 , R 3  and R 4 . A plurality of links R 1  are pivotably coupled to unison ring  36 , e.g., at one end. Each of the links R 1  is also coupled to a vane  26  of vane stage  24 , e.g., at the other end. Each link R 1  is operable to rotate the vane  26  to which it is coupled. Links R 1  may be, for example, sheet metal stampings. Rotational motion of unison ring  36  is transmitted through links R 1  to each vane  26 , whereby a rotation of unison ring  36  results in a rotation of each vane  26 . Hence, a rotation of unison ring  36  in one direction increases the angle of attack of vanes  26 , and a rotation of unison ring  36  in the opposite direction decreases the angle of attack of vanes  26 . 
     A plurality of links R 2  are pivotably coupled to unison ring  38 , e.g., at one end. Each of the links R 2  is also coupled to a vane  30  of vane stage  28 , e.g., at the other end. Each link R 2  is operable to rotate the vane  30  to which it is coupled. Links R 2  may be, for example, sheet metal stampings. Rotational motion of unison ring  38  is transmitted through links R 2  to each vane  30 , whereby a rotation of unison ring  38  results in a rotation of each vane  30 . Hence, a rotation of unison ring  38  in one direction increases the angle of attack of vanes  30 , and a rotation of unison ring  38  in the opposite direction decreases the angle of attack of vanes  30 . 
     A plurality of links R 3  are pivotably coupled to unison ring  36 , e.g., at one end. In one form, each link R 3  is coupled to unison ring  36  at the same circumferential location as link R 1  is coupled to unison ring  36 , although different coupling locations may be employed in other embodiments. Each link R 3  is also pivotably coupled to unison ring  38 , e.g., at the other end. In one form, each link R 3  is coupled to unison ring  38  at the same circumferential location as link R 2  is coupled to unison ring  38 , although different coupling locations may be employed in other embodiments. In one form, there is one link R 3  for each vane  30  in vane stage  28 . In other embodiments, greater or lesser numbers of links R 3  may be utilized. The number of links R 3  may vary with the loads anticipated during gas turbine engine  10  operations. 
     A plurality of links R 4  are pivotably coupled to vanes  26  and pivotably coupled to vanes  30 . In one form, links R 4  are stationary. In the present embodiment, compressor case  44  functions as plurality of links R 4  by being pivotably coupled with each vane  26  and each vane  30 . In other embodiments, links R 4  may take other forms. 
     Actuator  42  is configured to provide mechanical power to vane actuation system  34  to rotate vanes  26  and  30  in a controlled manner. In one form, actuator  42  is a hydraulic actuator. In other embodiments, actuator  42  may take other forms, and may be, for example, an electric actuator and/or a pneumatic actuator. In one form, actuator  42  is coupled directly to unison ring  36 , and is operable to supply an actuator force to impart rotation to unison ring  36 , e.g., a rotation in a circumferential direction  78 . In other embodiments, actuator  42  may be coupled directly to unison ring  38 , and may be operable to supply an actuator force to impart rotation to unison ring  38 , e.g., in circumferential direction  78 . In still other embodiments, actuator  42  may be coupled to indirectly to both unison ring  36  and unison ring  38 , e.g., via one or more links R 3 . In yet other embodiments, actuator  42  may be coupled to one or both of unison rings  36  and  38  by any convenient means in addition to or in place of arrangements set forth herein. 
     Referring now to  FIG. 3 , the operation of vane actuation system  34  is described. The operation of vane actuation system  34  begins with actuator  42  supplying an actuator force to impart rotation of unison ring  36 . Rotation of unison ring  36  in circumferential direction  78  imparts a rotation to each vane  26  via links R 1 , e.g., resulting in an angle  80  between link R 1  and a line  82  extending between axis of rotation  64  and axis of rotation  76 , which in one form may represent link R 4 . Rotation of unison ring  36  also imparts a rotation to unison ring  38  via link R 3 , e.g., also in circumferential direction  78 , which imparts a rotation to each vane  30  via links R 2 , e.g., resulting in an angle  84  between link R 2  and line  82 . Compressor case  44  functions as links R 4 . Angles  80  and  84  may be readily determined using four-bar linkage calculations. 
     Embodiments of the present invention include a vane actuation system for a turbine engine. The vane actuation system may include a unison ring for a vane stage of the turbine engine; a plurality of first links, each first link being coupled to a vane of the vane stage, and each first link being pivotably coupled to the unison ring; an other unison ring for an other vane stage of the turbine engine; a plurality of second links, each second link being coupled to an other vane of the second vane stage, and each second link being pivotably coupled to the other unison ring; a third link pivotably coupled to each unison ring; and a fourth link pivotably coupled to the vane and the other vane. 
     In one refinement, the vane actuation system further comprises an actuator operable to supply an actuator force to at least one of the unison ring and the other unison ring. The actuator may be coupled to one of the unison ring and the other unison ring. 
     In another refinement, a rotation of the first link is operable to rotate the vane; and a rotation of the second link is operable to rotate the other vane. 
     In yet another refinement, the fourth link is stationary. The fourth link may be a vane case of the turbine engine. The vane case may a compressor vane case. 
     In still another refinement, the third link is pivotably coupled to the unison ring at a same circumferential location as one of the first links. 
     In yet still another refinement, the third link is pivotably coupled to the other unison ring at a same circumferential location as one of the second links. 
     In a further refinement, the vane actuation may further comprise a plurality of third links pivotably coupled to each of the unison ring and the other unison ring. 
     Another embodiment of the present invention may be a turbine engine. The turbine engine may comprise at least one of a fan section, a compressor section and a turbine section; a vane stage, the vane stage being at least one of a fan stage, a compressor stage and a turbine stage; an other vane stage, the other vane stage being at least one of an other fan stage, an other compressor stage and an other turbine stage; and a vane actuation system. The vane actuation may include: a unison ring for the vane stage; a plurality of first links, each first link being coupled to a vane of the vane stage, and each first link being pivotably coupled to the unison ring; an other unison ring for the other vane stage; a plurality of second links, each second link being coupled to an other vane of the other vane stage, and each second link being pivotably coupled to the other unison ring; a third link pivotably coupled to each unison ring; and a fourth link pivotably coupled to a vane of the vane stage and a vane of the other vane stage. 
     In one refinement, the turbine engine may further comprise an actuator operable to supply an actuator force to at least one of the unison ring and the other unison ring. The actuator may be coupled to one of the unison ring and the other unison ring. 
     In another refinement, a rotation of the first link is operable to rotate the vane; and a rotation of the second link is operable to rotate the other vane. 
     In yet another refinement, the fourth link is stationary. In an additional refinement, the turbine engine may include a vane case for the at least one of the fan section, the compressor section and the turbine section, wherein the vane case serves as the fourth link. The vane case may be a compressor vane case. 
     In still another refinement, the third link may be pivotably coupled to the unison ring at a same circumferential location as one of the first links. 
     In a further refinement, the third link is pivotably coupled to the other unison ring at a same circumferential location as one of the second links. 
     In yet still another refinement, the turbine engine may further comprise a plurality of third links pivotably coupled to each of the unison ring and the other unison ring. 
     Yet another embodiment may include a turbine engine. The turbine engine may comprise at least one of a fan section, a compressor section and a turbine section; a vane stage, the vane stage being at least one of a fan stage, a compressor stage and a turbine stage; an other vane stage, the other vane stage being at least one of an other fan stage, an other compressor stage and an other turbine stage; and a vane actuation system. The vane actuation system may include means for coupling the rotation of the vanes of the vane stage with the rotation of the vanes of the other vane stage. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.