Abstract:
An exemplary turbine engine assembly includes a first shaft that is rotatably driven by a second shaft of a gas turbine engine and a compressor hub driven by the first shaft. The compressor hub is within a compressor section of the gas turbine engine. An epicyclic gear train is driven by the first shaft. A common attachment point secures the first shaft and the compressor hub to the second shaft.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/718,436, which was filed on 5 Mar. 2010. U.S. patent application Ser. No. 12/718,436 is a divisional of U.S. Pat. No. 7,704,178, which was filed on 5 Jul. 2006. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This disclosure relates to a gas turbine engine architecture. 
         [0003]    Gas turbine engines typically employ an epicyclic gear train connected to a turbine section of the engine, which is used to drive the turbo fan. In a typical epicyclic gear train, a sun gear receives rotational input from a turbine shaft through a compressor shaft. A carrier supports intermediate gears that surround and mesh with the sun gear. A ring gear surrounds and meshes with the intermediate gears. In arrangements in which the carrier is fixed against rotation, the intermediate gears are referred to as “star” gears and the ring gear is coupled to an output shaft that supports the turbo fan. In arrangements in which the ring gear is fixed against rotation, the intermediate gears are referred to as “planetary” gears and the carrier is coupled to the output shaft that supports the turbo fan. 
         [0004]    The epicyclic gear train gears must receive adequate lubrication during operation of the turbine engine. To this end, the carrier includes oil spray bars arranged between the intermediate gears and the sun gear to spray oil directly on those gears. Separate oil baffles, which may be integral with or separate from the carrier, are arranged between the intermediate gears to collect the sprayed oil and retain it in the area of the intermediate gears for prolonged lubrication before the oil is collected in a lubricant gutter associated with the ring gear. 
         [0005]    Prior art carrier arrangements have required multiple components and complicated assembly in order to accommodate the oil baffles. For example, one or both of the side walls of the carrier must be assembled around the intermediate gears resulting in a multi-piece carrier. Furthermore, separate oil spray bars and oil baffles complicate assembly and increase cost. What is needed is a simplified oil baffle and spray bar arrangement that enables a simpler and less expensive carrier design. 
       SUMMARY OF THE INVENTION 
       [0006]    A turbine engine assembly according to an exemplary embodiment of the present disclosure includes, among other things, a first shaft that is rotatably driven by a second shaft of a gas turbine engine, and a compressor hub driven by the first shaft. The compressor hub is within a compressor section of the gas turbine engine. An epicyclic gear train is driven by the first shaft. A common attachment point secures the first shaft and the compressor hub to the second shaft. 
         [0007]    In a further non-limiting embodiment of the foregoing turbine engine assembly, the turbine engine includes an epicyclic gear train that has a carrier and sun gear. Intermediate gears are arranged about, and intermesh with, the sun gear. The intermediate gears are supported by the carrier. 
         [0008]    In a further non-limiting embodiment of either of the foregoing gas turbine engine assemblies, the gas turbine engine includes a baffle secured to the carrier by a fastening member. The baffle includes a lubrication passage near at least one of the sun gear and intermediate gears for directing a lubricant on the at least one of the sun gear and intermediate gears. 
         [0009]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the turbine engine assembly includes a ring gear intermeshing with the intermediate gears and a third shaft interconnected to the ring gear. The first shaft is interconnected to the sun gear. 
         [0010]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the carrier is fixed relative to a housing, the third shaft drives a turbo fan, and the first shaft supports a compressor hub having compressor blades. 
         [0011]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the first shaft is a compressor shaft. 
         [0012]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the epicyclic gear train rotatably drives a third shaft. 
         [0013]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the turbine engine includes roller bearings that support the third shaft. 
         [0014]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the third shaft is a fan shaft. 
         [0015]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the second shaft is turbine shaft. 
         [0016]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the compressor hub includes blades. 
         [0017]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, torque is transferred to the first shaft and the compressor hub exclusively through the common attachment point. 
         [0018]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments, the common attachment point includes a fastener that extends through an aperture established in flange of the compressor hub, and an aperture established in a flange of the first shaft. 
         [0019]    A turbine engine assembly according to an exemplary embodiment of the present disclosure includes, among other things, a turbine shaft that is rotated by a turbine of a gas turbine engine, at least one compressor hub that is rotated by the turbine shaft. The at least one compressor hub within a compressor section of the gas turbine engine. The assembly includes a compressor shaft that is rotatably driven by the turbine shaft, and a epicyclic gear train that is driven by the compressor shaft. The at least one compressor hub and the compressor shaft are rotatably coupled to the turbine shaft at a common attachment point. 
         [0020]    In a further non-limiting embodiment of the foregoing gas turbine engine embodiment, the epicyclic gear train includes a carrier having spaced apart walls with circumferentially spaced mounts interconnecting the walls. The mounts provide circumferentially spaced apart apertures between the mounts at an outer circumference of the carrier. A sun gear and intermediate gears are arranged about and intermeshing with the sun gear. The intermediate gears are supported by the carrier. 
         [0021]    In a further non-limiting embodiment of either of the foregoing gas turbine engine embodiments, baffles are arranged between the walls near the mounts. The baffles are secured to at least one of the walls and the mounts by a fastening element, gear pockets are provided between the baffles, and the baffles including a lubrication passage terminating at least one of the gear pockets. 
         [0022]    In a further non-limiting embodiment of any of the foregoing gas turbine engine embodiments. The epicyclic gear train rotatably drives a fan shaft. Torque is transferred from the turbine shaft to the compressor shaft and from the turbine shaft to the compressor hub exclusively through the common attachment point. 
         [0023]    A method of operating a gas turbine engine according to an exemplary aspect of the present disclosure includes, among other possible things, applying torque to an epicyclic gear train of a gas turbine engine by rotating a turbine shaft using a turbine section of a gas turbine engine, rotating a compressor hub using the turbine shaft, and rotating a compressor shaft with the turbine shaft. The compressor shaft is configured to rotate an epicyclic gear train. The first shaft is secured to the compressor hub and the compressor shaft at a common attachment point. 
         [0024]    In a further non-limiting embodiment of the foregoing method, the method includes rotating a fan shaft with the epicyclic gear train. 
         [0025]    These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a partial cross-sectional view of a front portion of a gas turbine engine illustrating a turbo fan, epicyclic gear train and a compressor section. 
           [0027]      FIG. 2  is a cross-sectional view of the epicyclic gear train shown in  FIG. 1 . 
           [0028]      FIG. 3  is an end view of the epicyclic gear train taken along line  3 - 3  in  FIG. 2  with a pair of star gears shown in phantom in an installation position. 
           [0029]      FIG. 4  is an enlarged view of a portion of the epicyclic gear train shown in  FIG. 3  with a sun gear and star gears shown in phantom. 
           [0030]      FIG. 5  is an enlarged view of a portion of the epicyclic gear train shown in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0031]    A portion of a gas turbine engine  10  is shown schematically in  FIG. 1 . The turbine engine  10  includes a fixed housing  12  that is constructed from numerous pieces secured to one another. A compressor section  14  having compressor hubs  16  with blades are driven by a turbine shaft (not shown) about an axis A. A turbo fan  18  is supported on a turbo fan shaft  20  that is driven by a compressor shaft  24 , which supports the compressor hubs  16 , through an epicyclic gear train  22 . 
         [0032]    In the example arrangement shown, the epicyclic gear train  22  is a star gear train. Of course, the claimed invention also applies to other epicyclic gear trains such as a planetary arrangement. Referring to  FIG. 2 , the epicyclic gear train  22  includes a sun gear  28  that is connected to the compressor shaft  24 , which provides rotational input, by a splined connection  30 . 
         [0033]    In the example arrangement shown, the compressor shaft is a two-part shaft having a first shaft  24   a  and a second shaft  24   b . The first shaft  24   a  is connected to the second shaft  24   b  via a connection member  31 , which is a bolt and nut in this example. 
         [0034]    A carrier  34  is fixed to the housing  12  by a torque frame  36 . The carrier  34  supports intermediate gears (which are star gears  32  in the arrangement shown) that are coupled to the sun gear  28  by meshed interfaces  26  between the teeth of the sun and star gears  28 ,  32 . A ring gear  38  surrounds the carrier  34  and is coupled to the star gears  32  by meshed interfaces  44 . The ring gear  38 , which provides rotational output, is secured to the turbo fan shaft  20  by connection  42 . 
         [0035]    In one example, the torque frame  36  grounds the carrier  34  to the housing  12  in a known manner. For example, mounts  53  have apertures  56  receiving fingers of the torque frame  36 , as shown in  FIGS. 2 and 3 . Pins  48  that extend through spherical bearings  46  and bushings  52  secure the fingers to the carrier  34 . Fasteners  50  retain the pins  48  to the carrier  34 . 
         [0036]    The carrier  34  is a unitary structure manufactured from one piece for improved structural rigidity and ease of assembly. The carrier  34  includes spaced apart side walls  60  that are interconnected by the mounts  54 , which are generally wedge-shaped members, as best shown in  FIG. 3 . The mounts  54  and side walls  60  are unitary with one another. The mounts  54  have opposing curved surfaces  58  that are in close proximity to the star gears  32  and generally follow the curvature of the teeth of the star gears  32  so that any oil on the curved surfaces  58  will likely find its way to the star gears  32  for additional lubrication. 
         [0037]    The mounts  54  are circumferentially spaced about the carrier  34  to provide apertures  98  through which the star gears  32  extend to engage the ring gear  38 . Returning to  FIG. 2 , the side walls  60  include holes  62  for receiving a journal bearing  64  that supports each of the star gears  32 . Each journal bearing  64  is retained within the carrier  34  by retainers  66  fastened to the side walls  60 . 
         [0038]    Oil baffles  68  are arranged between the side walls  60  near each of the mounts  54 , best shown in  FIG. 2 . Referring to  FIGS. 4 and 5 , the baffles  68  include ends  72  that abut the mounts  54 , in the example shown. The baffles  68  also include opposing curved surfaces  70  arranged in close proximity to the star gears  28 . The curved surfaces  58 ,  70  are contiguous with and adjoin one another, in the example shown, and provide gear pockets  102  that receive the star gears  32 . A gear pocket  104 , which receives the sun gear  28 , is also provided between a surface  73  on each of the baffles  68  opposite the ends  72 . 
         [0039]    In one example, one of the side walls  60  includes holes  74  that receive fasteners  76  which secure each of the baffles  68  to the carrier  34 . The baffles  68  include a lubrication passage provided by a primary passage  86  that fluidly communicates with a lubricant distributor  78 . The lubricant distributor  78  is fed oil from a lubricant supply  96 . In one example, the baffles  68  include openings  82  that receive a tube  80  extending through a hole  83  in the side wall  60 . Seals  84  seal the tube  80  to the opening  82  and lubricant distributor  78 . Other tubes  92  having seals  84  are used to provide oil to an external spray bar  94  through another lubrication passage (spray bar passage  93  that extends through one of the baffles  68 ). The external spray bar  94  is secured to the carrier  34  and sprays oil in the vicinity of the sun gear  28  near the splined connection  30  (shown in  FIGS. 2 and 5 ). 
         [0040]    The primary passage  86  is in communication with first and second passages  88 ,  90  that spray oil on the teeth of the sun and star gears  28 ,  32 . In the example shown, the first and second passages  88 ,  90  are arranged ninety degrees from one another. 
         [0041]    With the example baffles  68 , lubricant distribution is integrated into the baffle so that separate components are eliminated. The baffles  68  can be constructed from a different, lighter weight material than the carrier  34 . 
         [0042]    The example carrier  34  can be constructed from one piece, which improves the structural integrity of the carrier. A central opening  100  is machined in at least one of the side walls  60  and provides the gear pocket  104 . Gear pockets  102  are machined between the side walls  60  and mounts  54  for each of the star gears  32  and form apertures  98  at an outer circumference of the carrier  34 . Referring to  FIG. 3 , the star gears  32  are inserted into the central opening  100  and moved radially outwardly so that they extend through the apertures  98  and are preferably in abutment with the mounts  54  (position indicated by dashed lines in  FIG. 3 ). In this position, there is an adequate gap, t, between the teeth of adjacent star gears  32  to accommodate a width, w, of the end  72  of the baffles  68 . Once the baffles  68  have been inserted, the star gears  32  can be repositioned, as shown by the solid lines, and the sun gear  28  can be inserted into the central opening  100  so that it meshes with the star gears  32 . The baffles  68  are secured to the carrier  34  using fasteners  76 . The tubes  80 ,  92  can be inserted and the rest of the lubricant distribution system can be connected. 
         [0043]    Although a preferred 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.