Abstract:
In various embodiments, a lubricating shaft assembly may comprise a shaft, a front seal, a front seat, an inner race, a spacer, a lubricating fitting and a nut. The front seat may define a first portion of a fluid conduit. The front seat may be part of a first load path. The inner race may define a second portion of the fluid conduit. The inner race may be installed about the shaft. The inner race may be part of the first load path. The spacer may define an internal diameter of a third portion of the fluid conduit. The lubricating fitting may be installed about at least a portion of the spacer. The lubricating fitting may define an outer diameter of the third portion of the fluid conduit. The lubricating fitting may be outside the first load path.

Description:
FIELD 
       [0001]    The present disclosure relates to systems and methods for load distribution and, more particularly, to systems and methods for load diversion around load sensitive parts through alternative load paths. 
       BACKGROUND 
       [0002]    A gas turbine engine may include a shaft with multiple components stacked axially together to form a shaft stack. The shaft stack components may be under relatively high axial loading. Where the stack components include a radial oil scoop, the large openings in the radial oil scoop may cause distortions to the other components in the stack. 
       SUMMARY 
       [0003]    In various embodiments, a lubricating shaft assembly may comprise a shaft, a front seal, a front seat, an inner race, a spacer, a lubricating fitting and a nut. The front seal installed about the shaft. The front seat may define a first portion of a fluid conduit. The front seat installed about the shaft. The front seat may be installed adjacent to the front seal. The front seat may be part of a first load path. The inner race may define a second portion of the fluid conduit. The inner race may be installed about the shaft. The inner race may be installed adjacent to the front seat. The inner race may be part of the first load path. The spacer may define an internal diameter of a third portion of the fluid conduit. The spacer may be installed about the shaft. The spacer may be installed adjacent to the inner race. The lubricating fitting may be installed about at least a portion of the spacer. The lubricating fitting may define an outer diameter of the third portion of the fluid conduit. The lubricating fitting may be outside the first load path and may be in a second load path. The nut may be configured to exert a load along the first load path. 
         [0004]    In various embodiments, a gas turbine engine may comprise a fan, a compressor, a combustor, a turbine, a shaft, a front seal, a front seat, a spacer, a lubricating, and a nut. The fan may be configured to create a fan flow. The combustor may be in fluid communication with the compressor. The turbine may be in fluid communication with the combustor. The turbine may be configured to drive the fan. The shaft may be installed through at least a portion of the fan, the compressor, and the turbine. The turbine may be configured to drive the shaft. The shaft may be configured to conduct power form the turbine to at least a portion of the compressor of the fan. A front seal installed about the shaft. The front seat may define a first portion of a fluid conduit. The front seat may be installed about the shaft and adjacent to the front seal. The front seat may be part of a first load path. The spacer may define an internal diameter of a second portion of the fluid conduit. The spacer may be installed about the shaft and aft the front seat. The lubricating fitting may be installed about at least a portion of the spacer. The lubricating fitting may define an outer diameter of the second portion of the fluid conduit. The lubricating fitting may be outside the first load path and being in a second load path. The nut may be configured to exert a load along the first load path and create a second load path. 
         [0005]    In various embodiments, a lubricating shaft assembly may comprise a spacer, a lubricating fitting, a wave spring, and a nut. The spacer may define an internal diameter of a first portion of a fluid conduit. The spacer may be installed about a shaft. The lubricating fitting may be installed about at least a portion of the spacer. The lubricating fitting may define an outer diameter of the first portion of the fluid conduit. The lubricating fitting may be outside the first load path and being in a second load path. The wave spring may be installed about the spacer and aft the lubricating fitting. The nut may be configured to define a first load path loaded through the spacer. The nut may also be configured to define a second load path through the wave spring and the lubricating fitting. 
         [0006]    The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, the following description and drawings are intended to be exemplary in nature and non-limiting. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0007]    The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures, wherein like numerals denote like elements. 
           [0008]      FIG. 1  is a cross-sectional view of an exemplary gas turbine engine in accordance with various embodiments; 
           [0009]      FIG. 2A  is a cross-sectional view of shaft stack configuration, in accordance with various embodiments; 
           [0010]      FIG. 2B  is an isometric view of shaft stack configuration, in accordance with various embodiments; and 
           [0011]      FIG. 3  is a cross-sectional view of an anti-rotating feature, in accordance with various embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the exemplary embodiments of the disclosure, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this disclosure and the teachings herein. Thus, the detailed description herein is presented for purposes of illustration only and not limitation. The scope of the disclosure is defined by the appended claims. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. 
         [0013]    Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Surface shading lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials. 
         [0014]    As used herein, “aft” refers to the direction associated with the tail (e.g., the back end) of an aircraft, or generally, to the direction of exhaust of the gas turbine. As used herein, “forward” refers to the direction associated with the nose (e.g., the front end) of an aircraft, or generally, to the direction of flight or motion. 
         [0015]    In various embodiments and with reference to  FIG. 1 , a gas turbine engine  100  (such as a turbofan gas turbine engine) is illustrated according to various embodiments. Gas turbine engine  100  is disposed about axial centerline axis A-A, which may also be referred to as axis of rotation A-A. Gas turbine engine  100  may comprise a fan  102 , compressor section  104 , a combustion section  106 , and a turbine section  108 . Air compressed in compressor section  104  may be mixed with fuel and burned in combustion section  106  and expanded across turbine section  108 . Fan  102 , compressor section  104 , and turbine section  108  may each contain rotating components that are adjacent to static components. Seals may be used to prevent air flow between rotating and static components. 
         [0016]    A plurality of bearings  105  may support spools in the gas turbine engine  100 . A main shaft  110  may enclose the axis of rotation A-A in the gas turbine engine  100 .  FIG. 1  provides a general understanding of the sections in a gas turbine engine, and is not intended to limit the disclosure. The present disclosure may extend to all types of turbine engines, including turbofan gas turbine engines and turbojet engines, for all types of applications. 
         [0017]    The forward-aft positions of gas turbine engine  100  lie along axis of rotation A-A. For example, fan  102  may be referred to as forward of turbine section  108  and turbine section  108  may be referred to as aft of fan  102 . Typically, during operation of gas turbine engine  100 , air flows from forward to aft, for example, from fan  102  to turbine section  108 . As air flows from fan  102  to the more aft components of gas turbine engine  100 , axis of rotation A-A may also generally define the direction of the air stream flow. 
         [0018]    In various embodiments and with reference to  FIG. 2A  and  FIG. 2B , a shaft stack  220  (also referred to as a lubricating shaft assembly) may be installable on shaft  210 . Shaft stack  220  may be configured to conduct one or more load paths. Shaft stack  220  may also be configured to distribute fluids. In this regard, shaft stack  220  may comprise a fluid flow path E. Fluid flow path E and/or shaft stack  220  may be in fluid communication with a fluid source or fluid reservoir. 
         [0019]    In various embodiments, shaft stack  220  may comprise a front seat  222 , an inner race  224 , a lubrication fitting  226 , a spacer  230 , a wave spring  240 , an aft seat  234  and a nut  232 . Shaft stack  220  may also comprise a front seal  236  and an aft seal  238 , which are shown in  FIG. 2A  but are not shown  FIG. 2B . Shaft  210  may comprise a shaft lip  212 . Shaft stack  220  may be installable on shaft  210 . In this regard. shaft stack may be installable about shaft  210  and may be seated on shaft lip  212 . 
         [0020]    In various embodiments, front seat  222  may be installed about shaft  210  and may seat against shaft lip  212 . Inner race  224  may be installed about shaft  210  adjacent to and aft of front seat  222 . Spacer  230  may be installed about shaft  210  adjacent to and aft of inner race  224 . Lubrication fitting  226  may be installed about shaft  210  on spacer  230 . Spacer  230  may comprise a spacer lip  231 . Wave spring  240  may be installable between spacer  230  and lubrication fitting  226  in gap D, as shown in  FIG. 2B . Wave spring may be retained between lubrication fitting  226  and spacer lip  231  and spacer  230 . Aft seat  234  may be installed on shaft  210  adjacent to and aft of spacer  230 . Nut  232  may be installed on shaft  210  adjacent to and aft of aft seat  234 . 
         [0021]    In various embodiments and with specific momentary reference to  FIG. 2A , shaft stack  220  may include front seal  236  installed adjacent to and forward of front seat  222 . Shaft stack  220  may include aft seal  238  installed adjacent to and aft of aft seat  234 . Front seal  236  and aft seal  238  may be configured to seal the forward and aft ends of shaft stack  220 . In this regard, front seal  236  and/or aft seal  238  may be configured to seal portions of fluid flow path E. The sealing may prevent leakage of fluid (e.g., cooling fluid, oil, and/or the like) outside the shaft stack  220  and/or fluid flow path E. 
         [0022]    In various embodiments and with reference to  FIGS. 2A and 2B , nut  232  may be configured to create an axial load G. Axial load G may be conducted along shaft  210  through aft seat, spacer  230 , inner race  224 , and front seat  222  to shaft lip  212 . Axial load G may be configured to load shaft stack  220  to minimize movement of shaft stack  220  and/or the movement between individual components of shaft stack  220 . Moreover, shaft stack  220  may be configured to conduct load G around lubrication fitting  226 . Nut  232  may also be configured to create an axial load F. Axial load F may be conducted to aft seat  234 , spacer  230 , wave spring  240  and lubrication fitting  226 . Axial load F may be generally less than axial load G. Moreover, axial load F may be configured to load and restrain the movement of lubrication fitting  226 , for example axial load F may constrain lubrication fitting  226  from rotation with respect to shaft  210 . 
         [0023]    In various embodiments, lubrication fitting may comprise one or more ports  228 . 
         [0024]    The geometry of lubrication fitting  226  and, more specifically, the ports  228  may make lubrication fitting  226  subject to deflection if the load on lubrication fitting  226  exceeded a threshold. For example, axial load G may be sufficiently high to cause lubrication fitting  226  to deflect and/or deform. The deflection and/or deformation of lubrication fitting  226  may also cause other components of shaft stack  220  to deform if lubrication fitting  226  is in the primary load path and subjected to axial load G. To avoid damage lubrication fitting  226  and/or other components of shaft stack  220 , lubrication fitting  226  is removed from the primary load path. 
         [0025]    In various embodiments, lubrication fitting may be loaded in a secondary load path by axial load F. The secondary load path may originate at nut  232  and be conducted through wave spring  240 . When loaded by axial load F, wave spring  240  may be compressed and gap D may be reduced and/or closed. Wave spring  240  may further translate axial load F to lubrication fitting  226 . Axial load F may be designed to load lubrication fitting  226  with sufficient force to restrain lubrication fitting  226  but not significantly deform lubrication fitting  226 . 
         [0026]    In various embodiments and with reference to  FIG. 3 , lubrication fitting  326  may include a retaining feature  327  (e.g., a tab or boss). Retaining feature  327  may be installable in a channel, hole, of slot defined in spacer  330 . In this regard, lubrication fitting  326  may be restrained by retaining feature  327  and an axial load (e.g., axial load F, as shown in  FIG. 2A ). 
         [0027]    Benefits and advantages have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, such benefits, advantages, and any elements that may cause any benefit or advantage to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. Reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. 
         [0028]    Systems, methods and apparatus are provided herein. In the detailed description herein, references to “various embodiments”, “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will he apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments. 
         [0029]    Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f), unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.