Abstract:
Aspects of the disclosure are directed to a fitting configured to couple a portion of a frame of a turbine and a bearing housing on an aircraft engine, comprising: a first receptacle configured to seat a tube that is configured to convey oil or air, and at least a second receptacle configured to seat a corresponding at least two bolts associated with the bearing housing, wherein the fitting comprises sections between the first receptacle and the at least a second receptacle that have a material thickness in a range of 3.175 millimeters and 6.35 millimeters.

Description:
BACKGROUND 
       [0001]    On some aircraft engines, a tubing may couple a frame, such as a mid-turbine frame, to a housing, such as a bearing housing, for purposes of conveying fluids (e.g., lubricants, such as oil). The tubing may be exposed to relatively elevated temperatures (e.g., on the order of 1800 degrees Fahrenheit), due to being placed in a gas path. A fitting coupling the tubing to the bearing housing may subjected to a temperature of approximately 500 degrees Fahrenheit. The bearing housing may operate at a temperature of approximately 350 degrees Fahrenheit. 
         [0002]    One or more seals are used in connection with the engines in an effort to ensure that the fluids do not leak. However, due to the large temperature gradients/differences between the various components (e.g., the tubing, the fitting, the bearing housing) during operation, gaps between the mating parts that axial seals connect may develop. If a gap exceeds a threshold, the potential exists for a leak to develop. 
       BRIEF SUMMARY 
       [0003]    The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosure. The summary is not an extensive overview of the disclosure. It is neither intended to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure. The following summary merely presents some concepts of the disclosure in a simplified form as a prelude to the description below. 
         [0004]    Aspects of the disclosure are directed to a fitting configured to couple a portion of a frame of a turbine and a bearing housing on an aircraft engine, comprising: a first receptacle configured to seat a tube that is configured to convey oil or air, and at least a second receptacle configured to seat a corresponding at least two bolts associated with the bearing housing, wherein the fitting comprises sections between the first receptacle and the at least a second receptacle that have a material thickness in a range of 3.175 millimeters and 6.35 millimeters. In some embodiments, the sections are approximately 5.1 millimeters thick thick. In some embodiments, the at least a second receptacle comprises three receptacles configured to seat three corresponding bolts. In some embodiments, the fitting further comprises a seal groove that is substantially located around the perimeter of the fitting. 
         [0005]    Aspects of the disclosure are directed to a system comprising: at least one tube, a bearing housing, and a fitting that includes: a first receptacle configured to seat the at least one tube, and at least a second receptacle configured to seat a corresponding at least one bolt associated with the bearing housing, wherein the fitting comprises sections between the first receptacle and the at least a second receptacle that have a material thickness in a range of 3.175 millimeters and 6.35 millimeters. In some embodiments, the sections are approximately 5.1 millimeters thick. In some embodiments, the at least a second receptacle comprises three receptacles configured to seat three corresponding bolts. In some embodiments, the system further comprises a seal groove that is substantially located around the perimeter of the fitting. In some embodiments, the at least one tube comprises at least two tubes. In some embodiments, a first of the at least two tubes is nested within a second of the at least two tubes. In some embodiments, the at least one tube is configured to convey oil or air. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements. 
           [0007]      FIG. 1  illustrates an exemplary gas turbine engine in accordance with aspects of this disclosure. 
           [0008]      FIG. 2  illustrates an assembly for fluidly coupling a portion of a turbine frame to a bearing housing. 
           [0009]      FIG. 3A  illustrates a first perspective view of a fitting of  FIG. 2 . 
           [0010]      FIG. 3B  illustrates a second perspective view of the fitting of  FIG. 2 . 
           [0011]      FIG. 4A  illustrates a first perspective view of a fitting in accordance with the prior art. 
           [0012]      FIG. 4B  illustrates a second perspective view of the fitting of  FIG. 4A  in accordance with the prior art. 
           [0013]      FIG. 5  illustrates a graph depicting a gap between the fitting of  FIGS. 4A-4B  over a range of temperature gradients/differences in accordance with the prior art. 
           [0014]      FIG. 6  illustrates a graph depicting a gap between the fitting of  FIGS. 3A-3B  over a range of temperature gradients/differences in accordance with aspects of this disclosure. 
           [0015]      FIG. 7  illustrates an assembly in accordance with the prior art. 
           [0016]      FIG. 8  illustrates an assembly in accordance with this disclosure. 
           [0017]      FIG. 9  illustrates a perspective view of the assembly of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. 
         [0019]    In accordance with various aspects of the disclosure, apparatuses, systems and methods are described for providing a tube for a lubrication or air system. The system may be used on an aircraft and may be incorporated in connection with one or more engines of the aircraft. Aspects of the disclosure are associated with a fitting of the tube. For example, aspects of the disclosure are associated with a profile of the fitting. 
         [0020]    Aspects of the disclosure may be applied in connection with an aircraft, or portion thereof. For example, aspects of the disclosure may be applied in connection with a gas turbine engine.  FIG. 1  is a side-sectional illustration of an exemplary gas turbine engine  10 . The engine  10  includes a compressor section  12 , a turbine section  14  and one or more engine hot sections. The engine hot sections may include, for example, a first engine hot section  16  configured as a combustor section and a second engine hot section  18  configured as an augmentor section. The compressor section  12 , the first engine hot section  16 , the turbine section  14  and the second engine hot section  18  may be sequentially aligned along an axial centerline  20  between a forward engine airflow inlet  22  and an aft engine airflow exhaust  24 . The second engine hot section  18  may include a first (e.g., annular, radial inner) duct case  26 , a second (e.g., annular, radial outer) duct case  28 , and one or more hot section vanes  30 . 
         [0021]    The engine  10  is illustrative. Aspects of the disclosure may be applied in connection with other engine types or configurations. 
         [0022]    Referring to  FIG. 2 , a system assembly  200  in accordance with aspects of the disclosure is shown. The system  200  includes a tube  202  that may be used to convey fluids (e.g., oil). In some embodiments, the tube  202  may include multiple tubes; for example, the tube  202  may include a first, interior tube nested within a second, exterior tube. 
         [0023]    The tube  202  may couple to a first fitting  204 . The fitting  204  may include one or more receptacles. A first receptacle  204 - 1  may be configured to couple to/seat the tube  202 . A second receptacle  204 - 2  may be configured to couple to/seat a first bolt associated with a bearing housing (not shown in  FIG. 2 , but shown and described below in connection with  FIGS. 7-8 ). A third receptacle  204 - 3  may be configured to couple to/seat a second bolt associated with the bearing housing. Any number of bolts or receptacles may be used in some embodiments. 
         [0024]    The tube  202  may couple to a (portion of a) frame or support structure associated with a turbine (e.g., turbine section  14  of  FIG. 1 ) towards an end  206  of the tube  202 . 
         [0025]    Referring to  FIGS. 3A-3B  (collectively referred to as  FIG. 3 ), a closer view of the fitting  204  is shown. As shown in  FIG. 3 , the fitting may include relatively thin sections of material  314  between receptacles  204 - 1  through  204 - 4  (where receptacle  204 - 4  may be configured to couple to/seat a third bolt associated with the bearing housing). In some embodiments, the sections  314  may be approximately two-tenths of an inch (0.2″) (or approximately 5.1 millimeters) thick. In some embodiments, the thickness may be between approximately one-eighth of an inch (0.125″) (or approximately 3.175 millimeters) and one-quarter of an inch (0.25″) (or approximately 6.35 millimeters). 
         [0026]    As shown in  FIG. 3 , the fitting  204  may include a seal groove  334 . The seal groove  334  may be substantially located around the perimeter of the fitting  204 . The seal groove  334  may be used for coupling/seating the fitting  204  with respect to a surface of the bearing housing. The seal groove  334  may help to ensure that the fitting  204  maintains contact with bearing housing within a threshold amount and potential leakage past the bolts is contained by the seal. 
         [0027]    In contrast to  FIG. 3 ,  FIGS. 4A-4B  (collectively referred to as  FIG. 4 ) illustrate a fitting  404  in accordance with the prior art. The fitting  404  includes a receptacle  404 - 1  for accommodating a tube (e.g., the tube  202  of  FIG. 2 ) and a seal groove  434  for coupling/seating the fitting  404  with respect to a bearing housing. Receptacles  404 - 2 ,  404 - 3 , and  404 - 4  may be used to couple to/seat bolts associated with the bearing housing. 
         [0028]    Unlike the fitting  204  of  FIGS. 2-3 , the fitting  404  does not include thin sections of material  314  between receptacles  404 - 1  through  404 - 4 . Instead, the fitting  404  is manufactured generally in the form of a solid, uniform block with material section  414  thickness of approximately eight-tenths of an inch (0.8″) (or approximately 20.3 millimeters). 
         [0029]    The use of the thin material section  314  may enable the fitting  204  to maintain a more consistent sealing interface relative to the fitting  404  over temperature. This is reflected in the graphs  500  and  600  depicted in  FIGS. 5-6 . In  FIG. 5 , which is indicative of the use of the fitting  404 , a gap  504  (the value of which is reflected on the vertical or y-axis (in inches)) between the fitting  404  and the bearing housing approaches an “allowable gap” threshold  506  (within a margin of 7%) as a temperature gradient/difference (as reflected on the horizontal or x-axis) approaches, or slightly exceeds, 200 degrees Fahrenheit (or approximately 93 degrees Celsius). In  FIG. 6 , which is indicative of the use of the fitting  204 , a gap  604  between the fitting  204  and the bearing housing maintains a margin of approximately 50% with respect to the same “allowable gap” threshold  506  of  FIG. 5 . 
         [0030]    In accordance with aspects of this disclosure, and based on a comparison of  FIG. 3  relative to  FIG. 4 , a seal may be placed on the outside of bolts that are used so that if leaking were to occur by gaps occurring around the location of bolts the fluid would be contained by the seal. 
         [0031]    Referring now to  FIG. 7 , an assembly  700  in accordance with the prior art is shown. The assembly  700  includes the tube  202  coupled to the fitting  404 , and a bearing housing  710  coupled to the fitting  404 . Bolts associated with the bearing housing  710  are inadequate to sufficiently reduce thermal distortion on the fitting  404 , resulting in excessive gapping as reflected via the reference character  704 . The gapping  704  may correspond to the gap  504  of  FIG. 5 . 
         [0032]      FIG. 8  illustrates an assembly  800  in accordance with aspects of this disclosure. In contrast to the assembly  700 /gap  704 , the assembly  800  incurs less, if any, gap  804  (where the gap  804  may correspond to the gap  604  of  FIG. 6 ). This minimization/reduction in the gap may be a function of the stiffness of the bolts in comparison to the fitting  204  allowing for a quality seating of the fitting  204  to the bearing housing  710 . 
         [0033]      FIG. 9  is a perspective view of the assembly  800  of  FIG. 8 . In this perspective view, two bolts (denoted by reference characters  904 - 2  and  904 - 4 ) of the bearing housing  710  that are associated with the receptacles  204 - 2  and  204 - 4  are shown. 
         [0034]    Technical effects and benefits of this disclosure include a fitting that maintains a higher-quality sealing contact/interface with a bearing housing. In accordance with aspects of this disclosure, this enhanced sealing may be obtained by as a result of the use of thin material sections between receptacles (e.g., tube or bolt receptacles) of the fitting. The use of such thin material sections may enable a ratio of bolt loading to fitting stiffness to increase, allowing for more thermal compliance of the fitting to mating hardware associated with the bearing housing. 
         [0035]    Aspects of the disclosure have been described in teens of illustrative embodiments thereof. Numerous other embodiments, modifications, and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps described in conjunction with the illustrative figures may be performed in other than the recited order, and that one or more steps illustrated may be optional in accordance with aspects of the disclosure. One or more features described in connection with a first embodiment may be combined with one or more features of one or more additional embodiments.