Abstract:
Disclosed is a gas turbine engine configured to include a propulsor section having a fan drive geared architecture. The gas turbine engine includes a gas generator section that includes a compressor section having a first rotor rotationally mounted to a first spool. The engine further includes a bearing package adapted for rotationally supporting the first spool. The bearing package is configured for supporting the first rotor during at least one of (1) a period prior to installation of the fan drive geared architecture into the engine and (2) a period after removal of the fan drive geared architecture from the engine.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present disclosure claims the benefit of U.S. Provisional Application No. 61/789,224, filed Mar. 15, 2013. Further, the present disclosure is a continuation of U.S. patent application Ser. No. 13/732,647, filed Jan. 22, 2013, which is a continuation of U.S. patent application Ser. No. 13/282,919, filed on Oct. 27, 2011, which is a continuation-in-part application of U.S. patent application Ser. No. 13/087,579, filed 15 Apr. 2011, and of U.S. patent application Ser. No. 13/275,286, filed 17 Oct. 2011. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to a gas turbine engine, and in particular, to a case structure therefor. 
         [0003]    Gas turbine engines typically include one or more rotor shafts that transfer power and rotary motion from a turbine section to a compressor section and fan section. The rotor shafts are supported within an engine static structure which is typically constructed of modules with individual case sections which are joined together at bolted flanges. The flanges form a joint capable of withstanding the variety of loads transmitted through the engine static structure. An ongoing issue for gas turbine engines is the ease and speed at which they can be serviced. 
       SUMMARY 
       [0004]    In one exemplary embodiment, a gas turbine engine is configured to include a propulsor section having a fan drive geared architecture. The engine includes a gas generator section that includes a compressor section having a first rotor rotationally mounted to a first spool. Further included is a bearing package rotationally supporting the first spool. The bearing package supports the first spool during at least one of (1) a period prior to installation of the fan drive geared architecture into the engine and (2) a period after removal of the fan drive geared architecture from the engine. 
         [0005]    In a further embodiment of any of the above, the first spool is a low spool of the engine. 
         [0006]    In a further embodiment of any of the above, the fan drive geared architecture drives a fan section at a speed different than a speed of the low spool. 
         [0007]    In a further embodiment of any of the above, a front center body support is defined around an engine longitudinal axis. 
         [0008]    In a further embodiment of any of the above, the bearing package is mounted to the front center body support and the low spool. 
         [0009]    In a further embodiment of any of the above, an engine static structure is included. 
         [0010]    In a further embodiment of any of the above, the bearing package is adapted for rotationally supporting the first spool against the static structure. 
         [0011]    Another exemplary embodiment includes a method of supporting a first rotor of a gas turbine engine. The engine is configured to include a propulsor section having a fan drive geared architecture. The engine further includes a gas generator section that includes a compressor section having a first rotor rotationally mounted to a first spool, an engine static structure, and a bearing package adapted for rotationally supporting the first spool against the engine static structure. The method includes supporting the first rotor with the bearing package during at least one of (1) a period prior to installation of the fan drive geared architecture into the engine and (2) a period after removal of the fan drive geared architecture from the engine. 
         [0012]    In a further embodiment of any of the above, the compressor section includes a low pressure compressor. 
         [0013]    In a further embodiment of any of the above, the bearing package supports the first rotor during each of (1) before the fan drive geared architecture into the engine and (2) after the fan drive geared architecture is removed from the engine. 
         [0014]    In a further embodiment of any of the above, the fan drive geared architecture includes a gearbox. 
         [0015]    In a further embodiment of any of the above, the bearing package supports a low rotor of the engine. 
         [0016]    In a further embodiment of any of the above, the geared architecture is serviced while removed from the engine. 
         [0017]    Another exemplary embodiment a method of partially disassembling a gas turbine engine. The engine includes a propulsor section having a fan drive geared architecture, a gas generator section that includes a compressor section having a first rotor rotationally mounted to a first spool, an engine static structure, and a bearing package adapted for rotationally supporting the first spool relative to the static structure. The method includes removing the propulsor section without otherwise supporting the first rotor, whereby the bearing package disposed within the engine supports the first rotor. 
         [0018]    In a further embodiment of any of the above, the compressor section includes is a low pressure compressor. 
         [0019]    In a further embodiment of any of the above, the bearing package is provided in a bearing compartment of the engine. 
         [0020]    In a further embodiment of any of the above, the geared architecture includes a gearbox. 
         [0021]    In a further embodiment of any of the above, the first rotor is the low rotor of the engine. 
         [0022]    In a further embodiment of any of the above, the geared architecture is serviced while removed from the engine. 
         [0023]    In a further embodiment of any of the above, the bearing package is adapted for rotationally supporting the first spool against the static structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiment. The drawings that accompany the detailed description can be briefly described as follows: 
           [0025]      FIG. 1  is a schematic cross-section of an embodiment of a gas turbine engine; 
           [0026]      FIG. 2  is an enlarged cross-section of a portion of the gas turbine engine which illustrates a front center body assembly; 
           [0027]      FIG. 3  is an enlarged cross-section of the geared architecture of the gas turbine engine; 
           [0028]      FIG. 4  is an exploded perspective view of a front center body assembly; 
           [0029]      FIG. 5  is an enlarged perspective partial cross-section of a front center body support of the front center body assembly; 
           [0030]      FIG. 6  is an enlarged sectional view of the front center body support; 
           [0031]      FIG. 7  is an exploded view of the front center body support; and 
           [0032]      FIG. 8  is a schematic view of a forward gearbox removal from the gas turbine engine. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]      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 propulsor section that includes a fan section  22 , and a gas generator section that includes 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 flowpath while the compressor section  24  drives air along a core flowpath 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. 
         [0034]    The engine  20  generally includes a low spool  30  and a high spool  32  mounted for rotation about an engine central longitudinal axis A relative to an engine static structure  36  via several bearing supports  38 . The low 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  drives the fan  42  through a geared architecture  48  to drive the fan  42  at a lower speed than the low spool  30 . For purposes of relating to the disclosed embodiments, the geared architecture is considered part of the propulsor section. The high 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 . The inner shaft  40  and the outer shaft  50  are concentric and rotate about the engine central longitudinal axis A which is collinear with their longitudinal axes. 
         [0035]    Core airflow is compressed by the low pressure compressor  44  then the high pressure compressor  52 , mixed with the fuel and burned in the combustor  56 , then expanded over the high pressure turbine  54  and low pressure turbine  46 . The turbines  54 ,  46  rotationally drive the respective low spool  30  and high spool  32  in response to the expansion. 
         [0036]    The main engine shafts  40 ,  50  are supported at a plurality of points by the bearing system  38  within the static structure  36 . In one non-limiting embodiment, bearing system  38  includes a #2 bearing support  38 A located within the compressor section  24 . 
         [0037]    With reference to  FIG. 2 , the engine static structure  36  proximate the compressor section  24  includes a front center body assembly  60  adjacent a #2 bearing support  38 A. The front center body assembly  60  generally includes a front center body support  62 . The #2 bearing support  38 A generally includes a seal package  64 , a bearing package  66 , a flex support  68  and a centering spring  70 . 
         [0038]    With reference to  FIG. 3 , the flex support  68  provides a flexible attachment of the geared architecture  48  within the front center body support  62  (also illustrated in  FIG. 4 ). The flex support  68  reacts the torsional loads from the geared architecture  48  and facilitates vibration absorption as well as other support functions. The centering spring  70  is a generally cylindrical cage-like structural component with a multiple of beams which extend between flange end structures (also illustrated in  FIG. 4 ). The centering spring  70  resiliently positions the bearing package  66  with respect to the low spool  30 . In one embodiment, the beams are double-tapered beams arrayed circumferentially to control a radial spring rate that may be selected based on a plurality of considerations including, but not limited to, bearing loading, bearing life, rotor dynamics, and rotor deflection considerations. 
         [0039]    The front center body support  62  includes a front center body section  72  and a bearing section  74  defined about axis A with a frustro-conical interface section  76  therebetween ( FIG. 5 ). The front center body section  72  at least partially defines the core flowpath into the low pressure compressor  44 . The front center body section  72  includes an annular core passage with a multiple of front center body vanes  72 A,  72 B. The bearing section  74  is defined radially inward of the front center body section  72 . The bearing section  74  locates the bearing package  66  and the seal package  64  with respect to the low spool  30 . The frustro-conical interface section  76  combines the front center body section  72  and the bearing section  74  to form a unified load path, substantially free of kinks typical of a conventional flange joint, from the bearing package  66  to the outer periphery of the engine static structure  36 . The frustro-conical interface section  76  may include a weld W ( FIG. 5 ) or, alternatively, be an integral section such that the front center body support  62  is a unitary component. 
         [0040]    The integral, flange-less arrangement of the frustro-conical interface section  76  facilitates a light weight, reduced part count architecture with an increased ability to tune the overall stiffness and achieve rotor dynamic requirements. Such an architecture also further integrates functions such as oil and air delivery within the bearing compartment which surrounds bearing package  66 . 
         [0041]    With reference to  FIG. 6 , the front center body support  62  includes mount features to receive the flex support  68 . In one disclosed non-limiting embodiment, the mount features of the front center body support  62  includes an internal spline  78  and a radial inward directed fastener flange  80  on the front center body section  72 . The flex support  68  includes a corresponding outer spline  82  and radially outwardly directed fastener flange  84 . The flex support  68  is received into the front center body support  62  at a splined interface  86  formed by splines  78 ,  82  and retained therein such that fastener flange  84  abuts fastener flange  80 . A set of fasteners  88  such as bolts are threaded into the fastener flanges  80 ,  84  to mount the flex support  68  within the front center body support  62 . 
         [0042]    With reference to  FIG. 7 , the fasteners  88  are directed forward to provide access from a forward section of the front center body assembly  60  opposite the bearing package  66  of the number two bearing system  38 A. The fasteners  88  are thereby readily removed to access a gearbox  90  of the geared architecture  48 . 
         [0043]    A front wall  102  aft of the fan  42  is mounted to a forward section of the front center body support  62  to provide access to the geared architecture  48  from the front of the engine  20 . The front wall  102  includes a flange  103  mountable to the front center body support  62  at the flange  60  by a multiple of fasteners  105 , which fasteners  105  may in one non-limiting embodiment be bolts. The front wall  102  and the front center body support  62  define a bearing compartment  100  (also shown in  FIG. 2 ) which mounts to the bearing package  66 . The front wall  102  is removable such that the gearbox  90  may be accessed as a module. The gearbox  90  may thereby be accessed to facilitate rapid on-wing service. 
         [0044]    It should be appreciated that various bearing structures  104  (illustrated schematically and in  FIG. 2 ) and seals  106  (illustrated schematically and in  FIG. 2 ) may be supported by the front wall  102  to contain oil and support rotation of an output shaft  108 . The output shaft  108  connects with the geared architecture  48  to drive the fan  42 . Fan blades  42 B extend from a fan hub  110  which are mounted to the output shaft  108  for rotation therewith. It should be appreciated that the bearing structures  104  and seals  106  may, in the disclosed non-limiting embodiment may be disassembled with the front wall  102  as a unit after removal of the fan hub  110 . 
         [0045]    The gearbox  90  is driven by the low spool  30  ( FIG. 1 ) through a coupling shaft  112 . The coupling shaft  112  transfers torque through the bearing package  66  to the gearbox  90  as well as facilitates the segregation of vibrations and other transients. The coupling shaft  112  generally includes a forward coupling shaft section  114  and an aft coupling shaft section  116  which extends from the bearing package  66 . The forward coupling shaft section  114  includes an interface spline  118  which mates with an aft spline  120  of the aft coupling shaft section  116 . An interface spline  122  of the aft coupling shaft section  116  connects the coupling shaft  112  to the low spool  30  through, in this non limiting embodiment, splined engagement with a spline  124  on a low pressure compressor hub  126  of the low pressure compressor  44 . 
         [0046]    To remove the gearbox  90 , the fan hub  110  is disassembled from the output shaft  108 . The multiple of fasteners  105  are then removed such that the front wall  102  is disconnected from the front center body support  62 . The multiple of fasteners  88  are then removed from the front of the engine  20 . The geared architecture  48  is then slid forward out of the front center body support  62  such that the interface spline  118  is slid off the aft spline  120  and the outer spline  82  is slid off the internal spline  78 . The geared architecture  48  is thereby removable from the engine  20  as a module ( FIG. 8 ; illustrated schematically). It should be appreciated that other componentry may need to be disassembled to remove the geared architecture  48  from the engine  20 , however, such disassembly is relatively minor and need not be discussed in detail. It should be further appreciated that other components such as the bearing package  66  and seal  64  are also now readily accessible from the front of the engine  20 . 
         [0047]    Removal of the gearbox  90  from the front of the engine  20  as disclosed saves significant time and expense. The geared architecture  48 , is removable from the engine  20  as a module and does not need to be further disassembled. Moreover, although the geared architecture  48  must be removed from the engine to gain access to the bearing package  66  and the seal  64 , the geared architecture  48  does not need to be removed from the engine  20  to gain access to the engine core itself. Further, as one would appreciate from the above, in an example where a portion of the geared architecture  48  itself requires service, the bearing package  66  can remain in place to support the low spool  30 , and in turn a low rotor, of the gas turbine engine  20  while the geared architecture  48  is removed for service. 
         [0048]    It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom. 
         [0049]    Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention. 
         [0050]    Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples. 
         [0051]    One of ordinary skill in this art would understand that the above-described embodiments are exemplary and non-limiting. That is, modifications of this disclosure would come within the scope of the claims. Accordingly, the following claims should be studied to determine their true scope and content.