Patent Publication Number: US-2023147099-A1

Title: Unison ring of gas turbine engine

Description:
TECHNICAL FIELD 
     The present disclosure relates to a unison ring which is located along an outer periphery of a casing of a gas turbine engine including a compressor, a combustor, and a turbine and is coupled to variable stator vanes of the compressor. 
     BACKGROUND ART 
     A gas turbine engine includes a compressor, a combustor, and a turbine which are lined up along a rotating shaft in a casing (see PTL 1, for example). The compressor includes: moving vanes connected to the rotating shaft; and variable stator vanes connected to the casing, A rotating shaft portion of the variable stator vane projects outside the casing. A unison ring is located at an outer periphery side of the casing. A pin in a pin hole of the unison ring is coupled to the rotating shaft portion of the variable stator vane through a lever. When the unison ring is rotated by an actuator along an outer peripheral surface of the casing by a desired angle, this rotation is transmitted through the lever to the rotating shaft portion of the variable stator vane, and this changes an angle of the variable stator vane. 
     CITATION LIST 
     Patent literature 
     PTL 1: Japanese Laid-Open Patent Application Publication No. 2014-47783 
     SUMMARY OF INVENTION 
     Technical Problem 
     When rotating the unison ring by the actuator, pressure received by the variable stator vane from compressed air in the compressor is applied as reaction force to the unison ring through the lever. Therefore, bending stress and torsional stress are generated in the unison ring, and this may deform the unison ring. When the unison ring is deformed, the angle of the variable stator vane deviates from a target angle. When there is an error in the angle of the variable stator vane, the operation of the compressor becomes unstable, and the deterioration of the efficiency of the compressor may occur. 
     An object of the present disclosure is to devise a unison ring to prevent deteriorations of operation stability and efficiency of a compressor of a gas turbine engine. 
     Solution to Problem 
     A unison ring of a gas turbine engine according to one aspect of the present disclosure is a unison ring of a gas turbine engine including a compressor, a combustor, and a turbine. The unison ring is located along an outer periphery of a casing of the gas turbine engine and coupled to variable stator vanes of the compressor. The unison ring includes: an annular body including fiber-reinforced resin or circular-arc bodies including the fiber-reinforced resin, the fiber-reinforced resin including resin and reinforced fibers; and pin holes in which a pin is in a radial direction orthogonal to an axial direction of the unison ring. A main orientation of the reinforced fibers of the fiber-reinforced resin is directed in a circumferential direction of the unison ring. 
     According to the above configuration, the unison ring includes the fiber-reinforced resin, and the main orientation of the reinforced fibers is directed in the circumferential direction of the unison ring. Therefore, the bending rigidity of the unison ring can be improved while reducing the weight of the unison ring. On this account, the error of the angle of the variable stator vane can be reduced, and the deteriorations of the operation stability and efficiency of the compressor of the gas turbine engine can be prevented. 
     Advantageous Effects of Invention 
     The present disclosure can improve the rigidity of the unison ring and prevent the deteriorations of the operation stability and efficiency of the compressor of the gas turbine engine. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic diagram showing a gas turbine according to an embodiment. 
         FIG.  2    is a front view of a unison ring of the gas turbine engine shown in  FIG.  1   . 
         FIG.  3 A  is a sectional view taken along line of  FIG.  2   .  FIG.  3 B  is a sectional view taken along line IIB-IIB of  FIG.  2   . 
         FIG.  4    is a partial perspective view of the unison ring shown in  FIG.  2   . 
         FIG.  5    is a sectional view of major components of the gas turbine engine to which the unison ring shown in  FIG.  2    is applied. 
         FIG.  6    is a diagram for explaining an operation trajectory of a pin hole of the unison ring when the unison ring and the like shown in  FIG.  5    are viewed from an outside in a radial direction. 
         FIG.  7 A  is a sectional view of the unison ring of Modified Example 1.  FIG.  7 B  is a sectional view of the unison ring of Modified Example 2.  FIG.  7 C  is a sectional view of the unison ring of Modified Example 3. 
         FIG.  8    is a graph showing bending rigidity values of the unison rings having respective sectional shapes, 
         FIG.  9    is a graph showing torsional rigidity values of the unison rings having the respective sectional shapes. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment will be described with reference to the drawings. 
       FIG.  1    is a schematic diagram showing a gas turbine according to the embodiment. As shown in  FIG.  1   ., a gas turbine engine  1  includes a casing  2 . The casing  2  houses a compressor  3 , a combustor  4 , and a turbine  5 . The compressor  3  and the turbine  5  are coupled to each other through a rotating shaft  6 . The compressor  3  rotates in association with the turbine  5  to compress air and supplies the compressed air to the combustor  4 . A combustion gas ejected from the combustor  4  rotates the turbine  5  and is discharged to an outside. The gas turbine engine  1  may be utilized as an aircraft engine, 
     The compressor  3  includes plural pairs of moving vane rows and stator vane rows. At least one of the stator vane rows of the compressor  3  includes variable stator vanes  11  (see  FIG.  5   ) lined up in a circumferential direction of the casing  2  such that angles of attack of the variable stator vanes  11  are adjustable. Unison rings  10  are externally fitted to the casing  2  so as to be lined up in an axial direction of the gas turbine engine  1 . The unison rings  10  are rotatable relative to an outer peripheral surface of the casing  2  in the circumferential direction. When the unison rings  10  are angularly displaced in the the circumferential direction (rotational direction) along the outer peripheral surface of the casing  2 , the angles of attack of the variable stator vanes  11  change. 
       FIG.  2    is a front view of the unison ring  10  of the gas turbine engine  1  shown in FIG. I.  FIG.  3 A  is a sectional view taken along line IIA-IIA of  FIG.  2   .  FIG.  3 B  is a sectional view taken along line of  FIG.  2   .  FIG.  4    is a partial perspective view of the unison ring  10  shown in  FIG.  2   . As shown in  FIGS.  2  to  4   , the unison ring  10  is an annular body made of fiber-reinforced resin by integral molding. The unison ring  10  may include separate circular-arc bodies located circumferentially and have a practically annular shape as a whole. 
     An axis X of the unison ring  10  passes through a center of the unison ring  10  and is orthogonal to a radial direction R of the unison ring  10 . A direction (hereinafter referred to as an “axial direction X”) in which the axis X of the unison ring  10  extends is a direction orthogonal to the radial direction R of the unison ring  10 . A circumferential direction C of the unison ring  10  is a direction along an outer peripheral surface of the unison ring  10 . To be specific, when viewed in the axial direction X, the circumferential direction C of the unison ring  10  is a direction along a circle whose center is the axis X of the unison ring  10 . 
     Regarding a section (section including the axis X of the unison ring  10 ) of the unison ring  10  orthogonal to the circumferential direction C, the unison ring  10  may adopt various sectional shapes. As one example, the unison ring  10  includes an inner plate  21 , an outer plate  22 , a coupling plate  23 , a pair of inner flange plates  24 , and a pair of outer flange plates  25 . Each of the inner plate  21  and the outer plate  22  has a cylindrical shape including main surfaces facing the radial direction R. The outer plate  22  is located concentrically with the inner plate  21  and away from the inner plate  21  outward in the radial direction R. The inner plate  21  includes pin holes  21   a  located at intervals in the circumferential direction, and the outer plate  22  includes pin holes  22   a  located at intervals in the circumferential direction. The pin holes  21   a  of the inner plate  21  and the pin holes  22   a  of the outer plate  22  coincide with each other when viewed in the radial direction R. 
     The coupling plate  23  has an annular flat plate shape including main surfaces facing the axial direction X. The coupling plate  23  couples one end of the inner plate  21  in the axial direction X to one end of the outer plate  22  in the axial direction X. An intermediate space S between the inner plate  21  and the outer plate  22  is open toward a side in the axial direction X which is opposite to a side at which the coupling plate  23  is. In other words, the unison ring  10  includes an opening Q between the other end of the inner plate  21  in the axial direction X and the other end of the outer plate  22  in the axial direction X. 
     Each of the pair of inner flange plates  24  has an annular flat plate shape including main surfaces facing the axial direction X. The pair of inner flange plates  24  are located away from each other in the axial direction X. The pair of inner flange plates  24  project inward in the radial direction R from both ends of the inner plate  21  in the axial direction X, respectively. Each of the pair of outer flange plates  25  has an annular flat plate shape including main surfaces facing the axial direction X. The pair of outer flange plates  25  are located away from each other in the axial direction X. The pair of outer flange plates  25  project outward in the radial direction R from both ends of the outer plate  22  in the axial direction X, respectively. 
     Each of the pair of outer flange plates  25  includes a support  25   a  partially projecting in the radial direction R. The support  25   a  is integrally molded as a part of the outer flange plate  25 . The support  25   a  includes a support hole H penetrating in the axial direction X. The support  25   a  is a portion to which driving power of a below-described actuator  18  is input to angularly displace the unison ring  10  relative to the casing  2  around the axis X. 
     In the present embodiment, the section of the unison ring  10  orthogonal to the circumferential direction C has a π shape when the axial direction X is set to an upper-lower direction. The section of the unison ring  10  orthogonal to the circumferential direction C has such a shape that a dimension L 1  of the unison ring  10  in the radial direction R is larger than a dimension L 2  of the unison ring  10  in the axial direction X regardless of the position of the section in the circumferential direction C,  1   b  be specific, “L 1 &gt;L 2 ” is satisfied in not only the section shown in  FIG.  3 B  but also the section shown in  FIG.  3 A . 
     As described above, the unison ring  10  is made of fiber-reinforced resin containing resin and reinforced fibers. The resin is a resin material selected from bismaleimide, epoxy, polyimide, and the like. The reinforced fibers are fibrous materials selected from carbon fibers, glass fibers, aramid fibers, and the like. The unison ring  10  is manufactured by laminating prepregs and subjecting the prepregs to pressing. The prepregs are prepared by impregnating reinforced fiber sheets with the resin. 
     The reinforced fiber sheets include, for example, a sheet made of a UD material in which reinforced fibers are oriented in one direction and a sheet made of a fabric material in which reinforced fibers are oriented in two directions. The orientation of the UD material extends in the circumferential direction C of the unison ring  10 . One of the orientations of the fabric material extends in the circumferential direction C of the unison ring  10 . For example, a ratio of the reinforced fibers extending in the circumferential direction C of the unison ring  10  to all the reinforced fibers of the fabric material may be 50% or more. 
     The most common orientations among all the orientations of the reinforced fibers in the entire unison ring  10  extend in the circumferential direction C of the unison ring  10 . To be specific, a main orientation of the reinforced fibers of the fiber-reinforced resin is directed in the circumferential direction C of the unison ring  10 . 
     The reinforced fiber sheets include first reinforced fiber sheets, second reinforced fiber sheet, and third reinforced fiber sheets. Two sheets among the first to third reinforced fiber sheets are partially laminated on each other. In the section of the unison ring  10  orthogonal to the circumferential direction C, the first to third reinforced fiber sheets are located so as to partially extend in different directions. 
     Therefore, there is a gap surrounded by the first to third reinforced fiber sheets. A reinforced fiber filler impregnated with the resin is in the gap. Therefore, the decrease in strength due to the gap is prevented. For example, a reinforced fiber sheet rounded in a tubular shape may be used as the reinforced fiber filler. It is preferable that the main orientation of the reinforced fibers of the reinforced fiber filler be directed in the circumferential direction C of the unison ring  10 . 
       FIG.  5    is a sectional view showing major components of the gas turbine engine  1  to which the unison ring  10  shown in  FIG.  2    is applied. As shown in  FIG.  5   , a pin  13  is in the pin holes  21   a  and  22   a  of the inner and outer plates  21  and  22  of the unison ring  10  in the radial direction R in a state where the pin  13  is prevented from coming out. The pin  13  is in a first end portion  14   a  of a lever  14  so as to be rotatable. The first end portion  14   a  of the lever  14  is in connection with the pin  13  in the intermediate space S of the unison ring  10  so as to be rotatable and extends through the opening Q of the unison ring  10  in the axial direction X to an outside of the intermediate space S. 
     The variable stator vane  11  includes a stator vane main body  11   a  and a shaft  11   b . The stator vane main body  11   a  is a blade that contacts and rectifies a fluid in the compressor  3 . The shaft  1   b  projects from the stator vane main body  11  a outward in the radial direction R to an outside of the casing  2 . A second end portion  14   b  of the lever  14  is fixed to the shaft  11   b  of the variable stator vane  11  by a fastener  15  so as not to be rotatable. A rotation axis Y of the variable stator vane  11  is an axis of the shaft  11   b . When the first end portion  14   a  of the lever  14  is displaced in the circumferential direction C, the second end portion  14   b  of the lever  14  angularly displaces the variable stator vane  11  around the axis Y. 
       FIG.  6    is a diagram for explaining an operation trajectory T of the pin hole  22   a  of the unison ring  10  when the unison ring  10  and the like shown in  FIG.  5    are viewed from an outside in the radial direction R. As shown in  FIG.  6   , both end portions of a pin  16  are in the support holes H (also see  FIG.  2   ) of the pair of outer flange plates  25  in a state where the pin  16  is prevented from coming out. The pin  16  is in a tip portion of a rod  17  so as to be rotatable. The rod  17  is driven by the actuator  18  so as to advance or retreat in the circumferential direction C along the outer peripheral surface of the unison ring  10 . For simplicity,  FIG.  2    shows that the actuator  18  is in direct connection with the rod  17 . However, as in PTL 1, a crank structure (not shown) and the like may be located between the actuator  18  and the rod  17 . 
     When the rod  17  advances or retreats by the driving power of the actuator  18 , the unison ring  10  is angularly displaced in the circumferential direction C around the axis X. With this, the pin  13  moves in the circumferential direction C, the lever  14  turns around the axis Y, and the variable stator vane  11  is angularly displaced around the axis Y. At this time, the driving power of the actuator  18  is input to the supports  25   a  of the unison ring  10 . Thus, a load is input to a part of the unison ring  10  in the circumferential direction C ( FIG.  2    shows two load input portions (supports  25   a )). Therefore, stress that causes bending deformation in the radial direction R is generated in the unison ring  10 . 
     Moreover, since the lever  14  has a fixed length, the pin  13  and the pin hole  22   a  move on the trajectory T having a circular-arc shape about the axis Y of the variable stator vane  11 . Therefore, in accordance with the advancing or retreating of the rod  17 , the unison ring  10  moves in the circumferential direction C and also moves slightly in the axial direction X. In this case, an advance-retreat direction of the rod  17  slightly deviates from the circumferential direction C of the unison ring  10 . Therefore, stress that causes torsional deformation around the circumferential direction C is generated in the unison ring  10 . 
     The sectional shape of the unison ring  10  is not limited to the above, and various sectional shapes may be adopted.  FIG.  7 A  is a sectional view of a unison ring  110  of Modified Example 1.  FIG.  7 B  is a sectional view of a unison ring  210  of Modified Example 2.  FIG.  7 C  is a sectional view of a unison ring  310  of Modified Example 3. The same reference signs are used for components common to the components of the unison ring  10 , and the repetition of the same explanation is avoided. 
     As shown in  FIG.  7 A , unlike the unison ring  10  shown in  FIG.  3 A , the unison ring  110  of Modified Example I does not include the opening Q that opens the intermediate space S between the inner plate  21  and the outer plate  22 . To be specific, in the unison ring  110 , one of the pair of coupling plates  23  couples one end of the inner plate  21  in the axial direction X to one end of the outer plate  22  in the axial direction X, and the other of the pair of coupling plates  23  couples the other end of the inner plate  21  in the axial direction X to the other end of the outer plate  22  in the axial direction X. Since the other components are the same as those of the unison ring  10 , explanations thereof are omitted. 
     As shown in  FIG.  7 B , the unison ring  210  of Modified Example 2 does not include the outer flange plates  25 . It is preferable that a dimension of the unison ring  210  in the radial direction R be larger than a dimension of the unison ring  210  in the axial direction X. Since the other components are the same as those of the unison ring  10 , explanations thereof are omitted, 
     As shown in  FIG.  7 C , the unison ring  310  of Modified Example 3 does not include the inner flange plates  24 . It is preferable that a dimension of the unison ring  310  in the radial direction R be larger than a dimension of the unison ring  310  in the axial direction X. Since the other components are the same as those of the unison ring  10 , explanations thereof are omitted. 
     Next, differences of bending rigidity and torsional rigidity between the unison rings having different sectional shapes will be discussed. Calculation results of bending rigidity values and torsional rigidity values of the unison rings having different sectional shapes were obtained by using computer simulation. In the present simulation, “Inspire” that is software produced by Altair Engineering was used. In the present simulation, conditions other than the sectional shape are set to be the same among the unison rings. 
       FIG.  8    is a graph showing the bending rigidity values of the unison rings having the respective sectional shapes,  FIG.  9    is a graph showing the torsional rigidity values of the unison rings having the respective sectional shapes. The sectional shape of “Base” is a rectangular shape that is the sectional shape of a conventional unison ring. The sectional shape of “Case  1 ” is an annular shape. The sectional shape of “Case 2” is an I shape. The sectional shape of “Case 3” is a horseshoe shape. The sectional shape of “Case 4” is the sectional shape shown in  FIG.  7 A . The sectional shape of “Case 5” is the sectional shape shown in  FIG.  3 A . The sectional shape of “Case 6” is the sectional shape shown in  FIG.  7 B . The sectional shape of “Case 7” is the sectional shape of  FIG.  7 C . Each of vertical axes of the graphs of  FIGS.  8  and  9    denotes a relative value based on a value of the sectional shape of Base. 
     It is clear from  FIG.  8    that the bending rigidity of the unison ring in each of Cases 2 to 7 is superior to the bending rigidity of the unison ring in each of Base and Case 1. Moreover, it is clear from  FIG.  9    that the torsional rigidity of the unison ring in each of Base and Cases 4 to 7 is superior to the torsional rigidity of the unison ring in each of Cases 2 and 3. Therefore, it is clear that both the bending rigidity and torsional rigidity of the unison ring in each of Cases 4 to 7 are superior. 
     According to the above configuration, the unison ring  10  includes the fiber-reinforced resin, and the main orientation of the reinforced fibers is directed in the circumferential direction C of the unison ring  10 . Therefore, the bending rigidity of the unison ring  10  can be improved while reducing the weight of the unison ring  10 . On this account, the error of the angle of the variable stator vane  11  can be reduced, and the deteriorations of the operation stability and efficiency of the compressor  3  of the gas turbine engine  1  can be prevented. 
     Moreover, the section of the unison ring  10  orthogonal to the circumferential direction C has such a shape that the dimension L 1  of the unison ring  10  in the radial direction R is larger than the dimension L 2  of the unison ring  10  in the axial direction X. Therefore, the bending rigidity of the unison ring  10  in the radial direction R can be further improved. 
     Moreover, the torsional rigidity can be improved by the flange plate portions  24  and  25  while reducing the weight and improving the bending rigidity by the coupling plate  23 . Furthermore, the intermediate space S between the inner plate  21  and the outer plate  22  is open toward a side in the axial direction X which is opposite to a side at which the coupling plate  23  is. Therefore, the lever  14  coupled to the variable stator vane  11  can be connected to the pin  13  in the intermediate space S between the inner plate  21  and the outer plate  22 . Thus, the degree of freedom of the layout can be improved. 
     Moreover, the resin used in the unison ring  10  is selected from bismaleimide, epoxy, polyimide, and the like, and the reinforced fibers used in the unison ring  10  are selected from carbon fibers, glass fibers, aramid fibers, and the like. Therefore, the unison ring  10  having high specific strength and high heat resistance can be realized. 
     The present disclosure is not limited to the above embodiment. Modifications, additions, and eliminations may be made with respect to the configuration of the embodiment. The sectional shape of the unison ring may be any shape as long as the unison ring is made of the fiber-reinforced resin, and the main orientation of the reinforced fibers is directed in the circumferential direction of the unison ring. For example, the sectional shape of the unison ring may be any of the shapes shown in  FIGS.  8  and  9   . The unison ring does not have to include the inner flange plates  24  and the outer flange plates  25 . When the unison ring does not include the inner flange plates  24  and the outer flange plates  25 , the lever  14  may be in connection with the pin  13  at an outside of the outer plate  22  in the radial direction R, or the lever  14  may be in connection with the pin  13  at an inside of the inner plate  21  in the radial direction R. The section of the unison ring  10  orthogonal to the circumferential direction C may have such a shape that the dimension of the unison ring  10  in the radial direction R is smaller than the dimension of the unison ring  10  in the axial direction X. 
     REFERENCE SIGNS LIST 
       1  gas turbine engine 
       2  casing 
       3  compressor 
       4  combustor 
       5  turbine 
       10 ,  110 ,  210 ,  310  unison ring 
       11  variable stator vane 
       21  inner plate 
       21   a  pin hole 
       22  outer plate 
       22   a  pin hole 
       23  coupling plate 
       24  inner flange plate 
       25  outer flange plate 
     C circumferential direction 
     G gap 
     Q opening 
     R radial direction 
     S intermediate space 
     T trajectory 
     X axial direction 
     Y axis