Patent Publication Number: US-9896971-B2

Title: Lug for preventing rotation of a stator vane arrangement relative to a turbine engine case

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This disclosure relates generally to a turbine engine and, more particularly, to a lug for preventing rotation of a stator vane arrangement relative to a turbine engine case. 
     2. Background Information 
     A stator vane arrangement for a typical turbine engine includes a plurality of stator vane airfoils circumferentially arranged around an axial centerline. The airfoils may extend radially between a radial inner platform and a radial outer platform. The outer platform may include a plurality of hooks that are mated with corresponding annular grooves in a turbine engine case. These hooks prevent the stator vane arrangement from moving radially and/or axially relative to the turbine engine case. A plurality of anti-rotation locks are provided to prevent the stator vane arrangement from rotating relative to the turbine engine case. 
     Various types of anti-rotation locks are known in the art. One such anti-rotation lock includes a rectangular lug that is connected to the turbine engine case with a plurality of fasteners. The rectangular lug is mated with a corresponding slot in the outer platform and, thereby, prevents the stator vane arrangement from rotating relative to the turbine engine case. 
     There is a need in the art for an improved anti-rotation lock. 
     SUMMARY OF THE DISCLOSURE 
     According to an aspect of the invention, an assembly is provided for a turbine engine wherein the assembly includes a stator vane arrangement and an anti-rotation lug that is rotatably connected to a turbine engine case. The stator vane arrangement includes a platform, an airfoil and an anti-rotation slot. The platform extends circumferentially around an axial centerline and is engaged with the case. The airfoil extends radially from the platform and is arranged circumferentially around the centerline. The slot extends radially into the platform, and is mated with the lug, which is configured with a substantially equilateral polygonal geometry. 
     According to another aspect of the invention, a turbine engine is provided that includes a core, a casing, a stator vane arrangement and an anti-rotation lug. The core includes a compressor section, a combustor section and a turbine section. The casing houses at least a portion of the core. The stator vane arrangement includes a platform, a plurality of airfoils and an anti-rotation slot. The platform extends circumferentially around an axial centerline and is engaged with the case. The airfoils extend radially from the platform and are arranged circumferentially around the centerline. The slot extends radially into the platform and is mated with the lug, which has a substantially equilateral polygonal geometry. 
     The substantially equilateral polygonal geometry may be a substantially square geometry with or without one or more chamfered corners. 
     The lug may have an axial lug width and a lateral lug width, which is substantially equal to the axial lug width. 
     The lug may include a plurality of platform engagement surfaces. One of the platform engagement surfaces may laterally engage (e.g., contact) a side surface of the slot. 
     A fastener may rotatably connect the lug to the case. The fastener may be axially and laterally centered to the lug. 
     The slot may also extend axially into the platform. The slot, for example, may extend axially into the platform through a hook of the platform. The hook may mate with an annular groove that extends axially into the case. 
     The slot may be one of a plurality of anti-rotation slots that are arranged circumferentially around the centerline. The lug may be one of a plurality of anti-rotation lugs that are respectively mated with the slots. The platform may include a plurality of arcuate platform segments. One or more of the platform segments may each be arranged with one or more of the airfoils and/or one of the slots. 
     The airfoils may extend radially inwards from the platform. Alternatively, the airfoils may extend radially outwards from the platform. 
     The stator vane arrangement may be arranged with the compressor section. Alternatively, the stator vane arrangement may be arranged with the turbine section. 
     The foregoing features and the operation of the invention will become more apparent in light of the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional illustration of a turbine engine; 
         FIG. 2  is an enlarged sectional illustration of a portion of the turbine engine of  FIG. 1 ; 
         FIG. 3  is an enlarged side illustration of a portion of the turbine engine of  FIG. 1 ; 
         FIG. 4  is a perspective illustration of a segment of a stator vane arrangement included in the turbine engine of  FIG. 1 ; 
         FIG. 5  is an illustration of a side of an anti-rotation lug included in the turbine engine of  FIG. 1 ; 
         FIG. 6  is an illustration of an end of the anti-rotation lug of  FIG. 5 ; and 
         FIG. 7  is an illustration of a side of an alternate embodiment anti-rotation lug. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a turbine engine  10  that extends along an axial centerline  12  between an upstream, airflow inlet  14  and a downstream, airflow exhaust  16 . The turbine engine  10  includes a plurality of sections such as, for example, a fan section  18 , one or more (e.g., low and high pressure) compressor sections  19  and  20 , a combustor section  21 , and one or more (e.g., high and low pressure) turbine sections  22  and  23 , which are sequentially arranged along the centerline  12 . The one or more compressor sections  19  and  20 , the combustor section  21  and the one or more turbine sections  22  and  23  collectively form a core  24  of the turbine engine  10 . 
     The turbine engine  10  also includes one or more stator assemblies (e.g.,  26  and  28 ). At least one of the stator assemblies may be configured to guide gas between two of the turbine engine sections  18 - 23 . The stator assembly  26 , for example, is configured to guide core gas from a rotor stage  29  of the compressor section  19  to an axially adjacent rotor stage  30  of the compressor section  20 . At least one of the stator assemblies may also or alternatively be configured to guide gas between adjacent rotor stages of a respective one of the turbine engine sections  18 - 23 . The stator assembly  28 , for example, is configured to guide core gas between adjacent rotor stages  31  and  32  of the compressor section  20 . 
     Referring to  FIGS. 2 and 3 , one or more of the stator assemblies (e.g., the stator assembly  28 ) includes a stator vane arrangement  34 , one or more anti-rotation lugs  36  (e.g., anti-rotation locks), and a turbine engine case  38  that may house, for example, at least a portion of the core  24  (see  FIG. 1 ). The stator vane arrangement  34  includes an annular outer vane arrangement platform  40 , a plurality of stator vane airfoils  42 , and one or more anti-rotation slots  44 . 
     The platform  40  extends axially between a first (e.g., upstream) platform end  46  and a second (e.g., downstream) platform end  48 . The platform  40  extends radially between a first platform surface  50  (e.g., a radial inner gaspath surface) and a second platform surface  52  (e.g., a radial outer surface). The platform  40  also extends circumferentially around the centerline  12  (see  FIG. 1 ). The platform  40  may include a plurality of arcuate platform segments  54 , one of which is illustrated in  FIG. 4 . The platform segment  54  embodiment of  FIG. 4  includes a first hook  56  and a second hook  58 . The first hook  56  includes an arcuate, axially extending flange arranged at (e.g., adjacent or proximate) the first platform end  46 . The second hook  58  includes an arcuate, axially extending flange arranged at the second platform end  48 . 
     One or more of the airfoils  42  extend radially (e.g., inwards) from the respective platform segment  54 , and are arranged circumferentially about the centerline  12  (see  FIG. 1 ). Each of the airfoils  42  extends axially between a leading edge  60  and a trailing edge  62 . Each of the vane airfoils  42  also extends laterally (e.g., generally circumferentially or tangentially) between a concave surface and a convex surface. In the embodiment of  FIG. 4 , the airfoils  42  and the respective platform segment  54  are formed (e.g., cast) as a unitary body. 
     Each of the slots  44  extends axially into a respective one of the platform segments  54  and through the second hook  58  to a distal end surface  64 . Each of the slots  44  extends radially into the respective platform segment  54  from the second platform surface  52  to a distal end surface  66 . Each of the slots  44  extends laterally between a first side surface  68  and a second side surface  70 , which defines a lateral slot width  72  as illustrated in  FIG. 3 . 
     Referring to  FIG. 5 , one or more (e.g., each) of the lugs  36  is configured with a substantially equilateral polygonal geometry. Each of the lugs  36 , for example, includes a plurality of platform engagement surfaces (e.g.,  73 - 76 ) with substantially equal widths (e.g.,  77  and  78 ). In the embodiment of  FIG. 5 , each of the lugs  36  has a substantially square geometry with one or more chamfered corners, and each lug  36  extends axially between the platform engagement surfaces  75  and  76 , which defines an axial lug width  79 . Each of the lugs  36  extends laterally between the platform engagement surfaces  73  and  74 , which defines a lateral lug width  80 . The lateral lug width  80  may be substantially equal to the axial lug width  79  as well as less than the lateral slot width  72  (see  FIG. 3 ). Referring to  FIG. 6 , each of the lugs  36  extends radially between a first (e.g., radial inner) end surface  81  and a second (e.g., radial outer) end surface  82 . Referring now to  FIGS. 5 and 6 , each of the lugs  36  includes a fastener aperture  84  that is axially and laterally centered between the engagement surfaces  73 - 76 . The fastener aperture  84  extends radially through the respective lug  36  between the first and the second end surfaces  81  and  82 . 
     Referring to  FIG. 2 , each of the lugs  36  is rotatably connected to the case  38  with a respective fastener  86  (e.g., rivet, bolt, etc.), which is mated with the fastener aperture  84 . Each of the lugs  36  is mated with (e.g., arranged in or extends into) a respective one of the slots  44 . Each of the second hooks  58  is mated with an annular groove  88  that extends axially into the case  38 . Each of the first hooks  56  is arranged radially between an annular air seal  90  and the case  38 . In this manner, the first and second hooks  56  and  58  may axially and/or radially constrain movement of the stator vane arrangement  34  relative to the case  38 . The lugs  36  may circumferentially constrain movement of the stator vane arrangement  34  relative to the case  38 . Referring to  FIG. 3 , for example, one of the platform engagement surfaces  73 - 76  (e.g., engagement surface  73 ) may engage (e.g., contact) one of the side surfaces  68  and  70  (e.g., the first side surface  68 ) to prevent the stator vane arrangement  34  from rotating relative to the case  38 . 
     The equilateral polygonal geometry of the lugs  36  may reduce the complexity and/or cost of manufacturing the turbine engine  10 . The equilateral polygonal geometry, for example, enables the lugs  36  to be connected to the case  38  without concern for which ones of the platform engagement surfaces  73 - 76  are adjacent to the side surfaces  68  and  70 . In addition, a misalignment between the platform engagement surface  73  and the first side surface  68  may be self-corrected when the respective lug  36  initially engages the platform  40  since the lug  36  may rotate about the fastener  86 . The equilateral polygonal geometry of the lugs  36  may also or alternatively reduce the complexity and/or cost of maintaining the turbine engine  10 . Instead of replacing the lug  36  when the platform engagement surface  73  has become worn, for example, the lug  36  may be rotated about the fastener  86  a quarter, a half or three-quarters of a turn, for example, such that another one of the platform engagement surfaces  74 - 76  engages the first side surface  68 . The equilateral polygonal geometry therefore may increase the service life of the lug  36  by four times. 
       FIG. 7  illustrates an alternate embodiment anti-rotation lug  92 . In contrast to the lug  36  of  FIG. 5 , the substantially equilateral polygonal geometry of the lug  92  is square without chamfered corners. The present invention, of course, is not limited to any particular equilateral polygonal geometry. 
     In some embodiments, the stator vane arrangement may also include an annular inner vane arrangement platform. The airfoils may extend radially between the inner and outer vane arrangement platforms. The present invention, however, is not limited to any particular stator vane arrangement configuration. 
     While various embodiments of the present invention have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. For example, the present invention as described herein includes several aspects and embodiments that include particular features. Although these features may be described individually, it is within the scope of the present invention that some or all of these features may be combined within any one of the aspects and remain within the scope of the invention. Accordingly, the present invention is not to be restricted except in light of the attached claims and their equivalents.