Abstract:
A liner and attachment structure has an exhaust liner for use in a gas turbine engine. At least one hanger has feet secured to the liner. The hanger has an aperture extending at a central web. A flanged washer is received within the opening in the hanger. The flanged washer allows adjustment relative to the hanger. The flanged washer has a spherical recess. A collet has a plurality of part-spherical fingers separated by slots, and are received in the spherical recess of the flanged washer. A member extends into the collet to hold the part-spherical fingers radially outwardly. The member is also utilized to secure static structure, and to secure the liner to the static structure.

Description:
BACKGROUND OF THE INVENTION 
     This application relates to a spherical collet received in a floating washer to mount a gas turbine nozzle liner to static structure. 
     Gas turbine engines are known, and typically include a compressor compressing air and delivering it into a combustion section where it is mixed with fuel and ignited. Products of this combustion pass downstream over a turbine rotor, driving it to rotate. The turbine rotor in turn drives the compressor rotor. 
     Downstream of the turbine rotors, the products of combustion exit through an exhaust nozzle. A liner typically faces the hot products of combustion, and must be mounted to static structure. Mounting the liner has raised challenges, in that the connection is subject to a number of stresses. 
     As an example, the mounting hardware must accommodate large misalignments between the static structure and the liner due to tolerances, complex shape, restricted physical access, significant pressure loads, high temperatures and resultant thermal growth mismatches. 
     Typically, the mounting hardware which has been utilized has been quite complex, and has not always allowed adequate adjustment. 
     In one known mounting arrangement, a pivot connection secures the liner to the static structure. As the liner is exposed to heat, it can expand in an axial direction. As the liner moves due to this expansion, the pivot connection causes a link arm connected to the static structure to move through an arc. With this movement, the mount structure may be pulled away from the liner. 
     In other challenges, the distance between the static structure and the liner to be accommodated by the mount structure must be precisely sized. This raises challenges due to tolerances on the liner or the static structure. Thus, the mounting structure must be specifically rigged for the particular liner and static structure, which of course raises the labor and machining costs. 
     In other arrangements, shims are necessary to accommodate the specific sizes. 
     SUMMARY OF THE INVENTION 
     In a featured embodiment, a liner and attachment structure has an exhaust liner for use in a gas turbine engine. There is at least one hanger having feet secured to the liner. The hanger has an aperture at a central web. A flanged washer is received within the aperture in the hanger, and is allowed adjustment relative to the hanger. The flanged washer has a spherical recess. A collet has a plurality of part-spherical fingers separated by slots. The part-spherical fingers are received in the spherical recess of the flanged washer. A member extends into the collet to hold the part-spherical fingers radially outwardly. The member is also utilized to be secured to static structure, to secure the liner to the static structure. 
     In another embodiment according to the previous embodiment, the member is one of a bolt or pin. 
     In another embodiment according to any of the previous embodiments, the member is mounted to the static structure and is secured with a lock nut. 
     In another embodiment according to any of the previous embodiments, an end of said flanged washer which faces said liner has an opening, and the member extending through the opening. 
     In another embodiment according to any of the previous embodiments, the flanged washer has an enclosed bore at an end facing the liner, such that the member does not extend through the bore. 
     In another embodiment according to any of the previous embodiments, a second washer is positioned on an opposed side of the hanger from the flanged washer. 
     In another embodiment according to any of the previous embodiments, the collet has threads on an outer periphery which can be adjusted relative to a static structure which is to be connected to the liner. 
     In another embodiment according to any of the previous embodiments, the aperture is received about a surface on the flanged washer with a clearance. The clearance allows the adjustability of the flanged washer relative to the hanger. 
     In another embodiment according to any of the previous embodiments, the feet may be bent relative to the central web to allow the hanger to be attached to a liner at a surface which is non-parallel to the central web. 
     In another featured embodiment, a gas turbine engine has a static structure and an exhaust liner for facing an exhaust duct. The exhaust liner is secured to the static structure by a system including at least one hanger. The hanger has feet secured to the liner. The hanger has an aperture extending at a central web. A flanged washer is received within the opening in the hanger. The flanged washer allows axial adjustment relative to the hanger. The flanged washer has a spherical recess. A collet has a plurality of part-spherical fingers separated by slots, with the part-spherical fingers received in the spherical recess of the flanged washer. A member extends into the collet to hold the part-spherical fingers radially outwardly. The member also is utilized to be secured to static structure, and to secure the liner to the static structure. 
     In another embodiment according to any of the previous embodiments, the member is one of a bolt or pin. 
     In another embodiment according to any of the previous embodiments, if the member is mounted to the static structure, it is secured with a lock nut. 
     In another embodiment according to any of the previous embodiments, an end of the flanged washer which faces the liner has an opening, and the member extends through the opening. 
     In another embodiment according to any of the previous embodiments, the flanged washer has an enclosed bore at an end facing the liner, such that the member does not extend through the bore. 
     In another embodiment according to any of the previous embodiments, a second washer is positioned on an opposed side of the hanger from the flanged washer. 
     In another embodiment according to any of the previous embodiments, the collet has threads on an outer periphery which can be adjusted relative to the static structure and liner. 
     In another embodiment according to any of the previous embodiments, the aperture is received about a surface on the flanged washer with a clearance. The clearance allows the adjustability of the flanged washer relative to the hanger. 
     In another embodiment according to any of the previous embodiments, at least one of the feet is bent relative to the central web to allow the hanger to be attached to the liner at a surface which is non-parallel to the central web. 
     In another featured embodiment, a method of attaching a liner to static structure includes the steps of attaching a hanger to a liner, and attaching mount structure to the hanger and to a static structure in a gas turbine engine, and adjusting the length of the mount structure by threadably adjusting the position of a portion of the mount structure to accommodate a distance between the liner and static structure. 
     In another embodiment according to the previous embodiment, the mount structure includes a collet which is threadably adjustable within a nut associated with the static structure. The collet extends into a flanged washer which receives the hanger. 
     These and other features may be best understood from the following specification and drawings, the following which is a brief description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically shows a gas turbine engine. 
         FIG. 2A  shows the mounting of a liner. 
         FIG. 2B  shows an alternative detail. 
         FIG. 3  shows a collet as incorporated into the  FIG. 2A  structure. 
         FIG. 4  is a cross-sectional view through  FIG. 2A . 
         FIG. 5  shows an alternative embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically illustrates a gas turbine engine  20 . The gas turbine engine  20  is disclosed herein as a two-spool turbofan that generally incorporates a fan section  22 , a compressor section  24 , a combustor section  26  and a turbine section  28 . Alternative engines might include an augmentor section (not shown) among other systems or features. The fan section  22  drives air along a bypass flow path B in a bypass duct defined within a nacelle  15 , while the compressor section  24  drives air along a core flow path C for compression and communication into the combustor section  26  then expansion through the turbine section  28 . Although depicted as a turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures. 
     The engine  20  generally includes a low speed spool  30  and a high speed spool  32  mounted for rotation about an engine central longitudinal axis A relative to an engine static structure  36  via several bearing systems  38 . It should be understood that various bearing systems  38  at various locations may alternatively or additionally be provided. 
     The low speed spool  30  generally includes an inner shaft  40  that interconnects a fan  42 , a low pressure compressor  44  and a low pressure turbine  46 . The inner shaft  40  is connected to the fan  42  through a geared architecture  48  to drive the fan  42  at a lower speed than the low speed spool  30 . The high speed spool  32  includes an outer shaft  50  that interconnects a high pressure compressor  52  and high pressure turbine  54 . A combustor  56  is arranged between the high pressure compressor  52  and the high pressure turbine  54 . A mid-turbine frame  57  of the engine static structure  36  is arranged generally between the high pressure turbine  54  and the low pressure turbine  46 . The mid-turbine frame  57  further supports bearing systems  38  in the turbine section  28 . The inner shaft  40  and the outer shaft  50  are concentric and rotate via bearing systems  38  about the engine central longitudinal axis A which is collinear with their longitudinal axes. 
     The core airflow is compressed by the low pressure compressor  44  then the high pressure compressor  52 , mixed and burned with fuel in the combustor  56 , then expanded over the high pressure turbine  54  and low pressure turbine  46 . The mid-turbine frame  57  includes airfoils  59  which are in the core airflow path. The turbines  46 ,  54  rotationally drive the respective low speed spool  30  and high speed spool  32  in response to the expansion. 
     The engine  20  in one example is a high-bypass geared aircraft engine. In a further example, the engine  20  bypass ratio is greater than about six (6), with an example embodiment being greater than ten (10), the geared architecture  48  is an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3 and the low pressure turbine  46  has a pressure ratio that is greater than about 5. In one disclosed embodiment, the engine  20  bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor  44 , and the low pressure turbine  46  has a pressure ratio that is greater than about 5:1. Low pressure turbine  46  pressure ratio is pressure measured prior to inlet of low pressure turbine  46  as related to the pressure at the outlet of the low pressure turbine  46  prior to an exhaust nozzle. The geared architecture  48  may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.5:1. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present invention is applicable to other gas turbine engines including direct drive turbofans. 
     A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The fan section  22  of the engine  20  is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet. The flight condition of 0.8 Mach and 35,000 ft, with the engine at its best fuel consumption—also known as “bucket cruise Thrust Specific Fuel Consumption (‘TSFC’)”—is the industry standard parameter of lbm of fuel being burned divided by lbf of thrust the engine produces at that minimum point. “Low fan pressure ratio” is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.45. “Low corrected fan tip speed” is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram° R)/(518.7° R)] 0.5 . The “Low corrected fan tip speed” as disclosed herein according to one non-limiting embodiment is less than about 1150 ft/second. 
     A mounting structure  80  for mounting an exhaust liner  84  to a static structure  82  is shown in  FIG. 2A . The liner faces hot products of combustion in a radially inner chamber  400 . As mentioned above, it has been challenging to mount such liners  84  to static structures  82 . 
     The inventive mounting features include a hanger  86  having two or more legs  88  which are attached with studs and collars  90  to the liner  84 . An opening in a central web  200  receives a washer  98 , as described below. 
     A pair of floating washers  98  and  100  allow axial and side-to-side misalignment between the hanger and the static structure  82  as will be explained below. 
     The flanged washer  98  includes a spherical cavity, as will be explained below, receiving a plurality of part-spherical fingers  96  on collet  92 . Slots  94  separate the fingers  96 . An upper end  99  of the collet  92  receives a self-locking nut  102 , and a bolt or pin  104  is driven into the collet  92  to ensure that the part-spherical fingers  96  are moved and/or remain outwardly in the recess within the flanged washer  98 . 
     The spherical connection allows angular misalignment and adjustment between the static structure  82  and the liner  84 , and the flanged washers  98 / 100  allow axial alignment. 
     As shown in  FIGS. 2A and 2B , a corner  305  connects the leg  88  to liner  84 . As shown in  FIG. 2A , the liner  84  is generally parallel to the central web  200 . However, as shown in  FIG. 2B , by bending the leg as shown at  310 , and at the corner  305 , the hanger  86  can be mounted to a liner  312  that has a more complex surface which is not parallel to the central web  200 . 
     Further, a bend at  306  can be adjusted to provide for a varying spring rate between the hanger  86  and the liner  84 . A collar  90  is shown to be received on a stud  201 . An opening  202  in the leg  88  is shown to be larger than the stud  201 , and this also allows some adjustment. This type of mount arrangement has been utilized in the prior art, but provides synergistic benefits in combination with the other adjustability as disclosed in this application. 
       FIG. 3  is a detail of the collet  92  and shows the slots  94  separating the part-spherical fingers  96 . Threads  300  are formed on an outer surface. 
       FIG. 4  is a cross-sectional view and shows details of the collet  92 , and the spherical recess  112  within the flanged washer  98 . As can be seen, there is clearance  190  between radially inner ends of the hanger  86 , and an outer surface of the washer  98 . This allows adjustment between the washer  98  and the hanger  86 , and hence adjustment between the washer  98  and the liner  84 . 
     As shown in  FIG. 4 , the collet  92  is threaded into the nut  102 . Thus, it can be tightened or loosened relative to the nut  102  to accommodate the tolerances or other variations between the location of the central web  200 , the washer  98 , and the static structure  82 . Thus, the problems mentioned above with regard to the necessity of rigging or shimming to accommodate the distances between the liner  84  and the static structure  82  are overcome by the adjustability of the collet  92 . 
     In addition, due to the clearance  190 , the liner  84  can adjust in its plane, and simply move within the clearance  190 . Thus, the problem mentioned above with regard to arcuate movement, and the mount structure being pulled away from the liner are overcome. 
     The washer  100  is threaded onto the washer  98 , capturing the central web  200 . Afterward, the threaded connection may be deformed in some manner such that the two washers  98  and  100  will not become loose. 
     As shown in  FIG. 4 , the bolt  104  has been driven inwardly such that the part-spherical fingers  96  are held outwardly within the recess  112 , and there is ability for relative adjustment between static structure  82  and the liner  84  via  92 , as mentioned above. 
     As shown in the  FIG. 4  embodiment, a bottom end  116  of the washer  98  is open, and a bottom end  114  of the pin  104  extends through that opening. 
       FIG. 5  shows an alternative embodiment wherein the washer  199  has a bottom bore  208 , and the bolt or the pin  204  has a bottom end  207  which is received within the bore  200 . There is clearance  190 , as in the prior embodiment. A stop  301  on washer  199  abuts a surface on washer  100 . 
     Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.