Abstract:
An assembly is provided that includes a shaft, a bearing, a stator seal element, a rotor seal element and a shield. The shaft extends along an axis. The bearing supports the shaft and receives lubrication fluid. The stator seal element circumscribes the shaft. The rotor seal element is mounted on the shaft axially between the bearing and the stator seal element. The rotor seal element forms a seal with the stator seal element. The shield substantially prevents the lubrication fluid from traveling axially away from the bearing onto the rotor seal element.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Appln. No. 61/787,334 filed Mar. 15, 2013, which is hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    This disclosure relates generally to rotational equipment and, more particularly, to an assembly including a bearing and a rotating seal element. 
         [0004]    2. Background Information 
         [0005]    A seal assembly is typically used in rotational equipment to provide a seal between regions of high and low fluid pressure and/or temperature. A seal assembly may be used, for example, to provide a gas and/or liquid seal between a stator and a rotor of a turbine engine, a pump, a compressor, a turbine of a hydro-electric or wind generator, as well as various other types of rotational equipment. 
         [0006]    A seal assembly for a turbine engine may include a lift-off face seal that is connected to a seal support. The seal support is connected to a stator with a plurality of fasteners. The seal support includes a plurality of coil springs that bias the face seal axially against a forward side of a seal landing. The seal landing is mounted on a shaft. The seal landing has an aft side that axially contacts an inner race of a bearing, which supports the shaft. 
         [0007]    During turbine engine operation, a side of the face seal and the forward side of the seal landing may be exposed to relatively hot air. A portion of this air may be directed into passages within the face seal to provide a film of air between the face seal and the seal landing. Heat energy may be transferred from the air into the seal landing, which may significantly increase the temperature of the seal landing. A portion of relatively cool lubrication oil may travel axially from the bearing onto the aft side of the seal landing. This lubrication oil may transfer the heat energy out of and thereby cool the seal landing. However, since air and lubrication oil typically have different heat transfer coefficients, the aft side of the seal landing may become significantly cooler than the forward side. The seal landing therefore may be subject to a relatively non-uniform temperature gradient, which may cause the seal landing to cone away from the face seal. Such coning may increase leakage between the face seal and the seal landing. 
         [0008]    There is a need in the art for an improved seal assembly. 
       SUMMARY OF THE DISCLOSURE 
       [0009]    According to an aspect of the invention, a turbine engine assembly is provided that includes a turbine engine shaft, a bearing, a rotor seal element and a shield. The shaft extends along an axis. The bearing includes an inner race and an outer race, where the inner race is mounted on the shaft and is separated from the outer race by a gap. The rotor seal element is mounted on the shaft. The shield substantially blocks an axial line of sight between the gap and the rotor seal element. 
         [0010]    According to another aspect of the invention, another turbine engine assembly is provided that includes a housing which defines an annular chamber, a turbine engine shaft, a bearing, a rotor seal element and a shield. The shaft extends along an axis into the chamber. The bearing supports the shaft within the chamber. The bearing includes an inner race and an outer race that is separated from the inner race by a gap. The rotor seal element is mounted on the shaft within the chamber. The rotor seal element includes a seal surface that faces away from the bearing. The shield includes a sleeve and a flange. The sleeve is mounted on the shaft axially between the bearing and the rotor seal element. The flange extends radially from the sleeve and substantially blocks a line of sight into the gap. 
         [0011]    According to still another aspect of the invention, an assembly is provided that includes a shaft, a bearing, a stator seal element, a rotor seal element and a shield. The shaft extends along an axis. The bearing supports the shaft, and receives lubrication fluid. The stator seal element circumscribes the shaft. The rotor seal element is mounted on the shaft axially between the bearing and the stator seal element. The rotor seal element forms a seal with the stator seal element. The shield substantially prevents the lubrication fluid from traveling axially away from the bearing onto the rotor seal element. 
         [0012]    The rotor seal element may include a seal surface that faces axially and/or radially away from the bearing. 
         [0013]    The bearing may include an inner race and an outer race. The inner race may be mounted on the shaft and separated from the outer race by a gap. The shield may substantially block an axial line of sight between the gap and the rotor seal element. 
         [0014]    The bearing may include an inner race and an outer race. The inner race may be mounted on the shaft and separated from the outer race by a gap. The shield may include a sleeve and an annular flange. The sleeve may be mounted on the shaft. The flange may substantially prevent the lubrication fluid from traveling axially from the bearing onto the rotor seal element. 
         [0015]    The bearing may receive lubrication fluid. The flange may substantially prevent the lubrication fluid from traveling out of the bearing onto the rotor seal element. 
         [0016]    The shield may be configured as an annular rotor shield that is mounted on the shaft axially between the inner race and the rotor seal element. 
         [0017]    The inner race may extend radially outward to an outer surface with a first radius. The outer race may extend radially inward to an inner surface with a second radius. The shield may extend radially outward to an outer surface with a third radius that is greater than the first radius and/or less than the second radius. 
         [0018]    The outer race may extend radially inward to an inner surface with a first radius. The shield may extend radially outward to an outer surface with a second radius that is substantially equal to or greater than the first radius. 
         [0019]    The shield may include a sleeve and an annular flange. The sleeve may be mounted on the shaft. The flange may substantially block the axial line of sight between the gap and the rotor seal element. 
         [0020]    The shield may axially engage (e.g., contact) the inner race or the rotor seal element. 
         [0021]    The assembly may include a spacer that is mounted on the shaft axially between the shield and the inner race. In addition or alternatively, the assembly may include a spacer that is mounted on the shaft axially between the shield and the rotor seal element. 
         [0022]    The inner race may extend radially outward to an outer surface with a first radius. The outer race may extend radially inward to an inner surface with a second radius. The shield may be configured as a stator shield that extends radially inward to an inner surface with a third radius that is greater than the first radius and/or less than the second radius. 
         [0023]    The inner race may extend radially outward to an outer surface with a first radius. The shield may be configured as a stator shield that extends radially inward to an inner surface with a second radius that is substantially equal to or less than the first radius. 
         [0024]    The assembly may include an annular stator seal element that axially engages and forms a seal with the rotor seal element. The rotor seal element may be arranged axially between the shield and the stator seal element. 
         [0025]    The stator seal element may be configured as a lift-off face seal. The rotor seal element may be configured as a face seal landing. 
         [0026]    The assembly may include a first rotor and a second rotor that are connected by the shaft. The first rotor may include a plurality of rotor blades that are connected to a rotor disk. The second rotor may include a plurality of rotor blades that are connected to a rotor disk 
         [0027]    The foregoing features and the operation of the invention will become more apparent in light of the following description and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is a side cutaway illustration of a geared turbine engine; 
           [0029]      FIG. 2  is a partial side sectional illustration of a turbine engine assembly for the engine of  FIG. 1  at a first circumferential location; 
           [0030]      FIG. 3  is a partial side sectional illustration of the engine assembly of  FIG. 2  at a second circumferential location; 
           [0031]      FIG. 4  is a side sectional illustration of a bearing for the engine assembly of  FIGS. 2 and 3 ; 
           [0032]      FIG. 5  is a side sectional illustration of a shield for the engine assembly of  FIGS. 2 and 3 ; 
           [0033]      FIG. 6  is a partial side sectional illustration of a portion of an alternate embodiment turbine engine assembly for the engine of  FIG. 1 ; 
           [0034]      FIG. 7  is a partial side sectional illustration of the engine assembly of  FIG. 2  during a mode of operation; 
           [0035]      FIG. 8  is a partial side sectional illustration of a portion of an alternate embodiment turbine engine assembly for the engine of  FIG. 1 ; and 
           [0036]      FIG. 9  is a partial side sectional illustration of a portion of another alternate embodiment turbine engine assembly for the engine of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]      FIG. 1  is a sectional illustration of a geared turbine engine  20  that extends along an axis  22  between a forward airflow inlet  24  and an aft airflow exhaust  26 . The engine  20  includes a fan section  28 , a low pressure compressor (LPC) section  29 , a high pressure compressor (HPC) section  30 , a combustor section  31 , a high pressure turbine (HPT) section  32 , and a low pressure turbine (LPT) section  33 . These engine sections  28 - 33  are arranged sequentially along the axis  22  and housed within an engine case  34 . 
         [0038]    Each of the engine sections  28 - 30 ,  32  and  33  includes a respective rotor  36 - 40 . Each of the rotors  36 - 40  includes a plurality of rotor blades arranged circumferentially around and connected (e.g., mechanically fastened, welded, brazed, adhered or otherwise attached) to one or more respective rotor disks. The fan rotor  36  is connected to a gear train  42 . The gear train  42  and the LPC rotor  37  are connected to and driven by the LPT rotor  40  through a low speed shaft  44 . The HPC rotor  38  is connected to and driven by the HPT rotor  39  through a high speed shaft  45 . The low and high speed shafts  44  and  45  are rotatably supported by a plurality of bearings  46 . Each of the bearings  46  is connected to the engine case  34  by at least one stator  48  such as, for example, an annular support strut. 
         [0039]    Air enters the engine  20  through the airflow inlet  24 , and is directed through the fan section  28  and into an annular core gas path  50  and an annular bypass gas path  52 . The air within the core gas path  50  may be referred to as “core air”. The air within the bypass gas path  52  may be referred to as “bypass air” or “cooling air”. The core air is directed through the engine sections  29 - 33  and exits the engine  20  through the airflow exhaust  26 . Within the combustion section  31 , fuel is injected into and mixed with the core air and ignited to provide forward engine thrust. The bypass air is directed through the bypass gas path  52  and out of the engine  20  to provide additional forward engine thrust or reverse thrust via a thrust reverser. The bypass air may also be utilized to cool various turbine engine components within one or more of the engine sections  29 - 33 . 
         [0040]      FIGS. 2 and 3  illustrate a turbine engine assembly  54  included in the engine  20  of  FIG. 1 . The engine assembly  54  includes one of the shafts  44 ,  45 , a seal assembly  56 , one of the bearings  46 , and an annular shield  58  (e.g., a rotor shield). The seal assembly  56  is adapted to seal a gap between one of the stators  48  and the respective shaft  44 ,  45 . The seal assembly  56  includes an annular seal support  60 , an annular stator seal element  62 , and an annular rotor seal element  64 . The stator seal element  62  may be configured as a hydrostatic seal such as a lift-off face seal. The rotor seal element  64  may be configured as a face seal landing. 
         [0041]      FIG. 4  illustrates the bearing  46  included in the engine assembly  54  of  FIGS. 2 and 3 . The bearing  46  extends axially between a bearing forward end  66  and a bearing aft end  68 . The bearing  46  includes an annular inner race  70 , an annular outer race  72 , and a plurality of bearing elements  74  (e.g., cylinders, cones or balls). These bearing elements  74  are arranged circumferentially around the axis  22 , and radially between the inner and the outer races  70  and  72 . 
         [0042]    The inner race  70  extends radially outward to a race outer surface  76  having a radius  78 . The outer race  72  circumscribes the inner race  70 , and extends radially inward to a race inner surface  80  having a radius  82  that is greater than the radius  78 . In the bearing  46  of  FIG. 4 , the radiuses  78  and  82  are measured at (e.g., on, adjacent or proximate) the forward end  66  for ease of illustration. One or both of these radiuses  78  and  82 , however, may alternatively be measured at another location along the outer and inner surfaces  76  and  80 . The radius  78 , for example, may be measured at a radial outer most location where the outer surface  76  has the largest radius. In another example, the radius  82  may be measured at a radial inner most location where the inner surface  80  has the smallest radius. An annular gap  84  extends radially between the inner and the outer surfaces  76  and  80  at the forward end  66 . 
         [0043]      FIG. 5  illustrates the shield  58  included in the engine assembly  54  of  FIGS. 2 and 3 . The shield  58  extends axially between a shield forward end  86  and a shield aft end  88 . The shield  58  includes a tubular sleeve  90  and an annular disk  92  (e.g., an annular flange). The sleeve  90  extends axially between the forward and the aft ends  86  and  88 , thereby defining an axial sleeve width  94 . The sleeve  90  extends radially from a shield inner surface  96  to the disk  92 , thereby defining a radial sleeve thickness  98  that may be less than the sleeve width  94 . The disk  92  is axially offset from the forward end  86  and/or the aft end  88 . The disk  92  extends axially between opposing surfaces  100 , thereby defining an axial disk width  102  that is less than the sleeve width  94 . The disk  92  extends radially out from the sleeve  90  to a shield outer surface  104 , thereby defining a radial disk thickness  106 . This disk thickness  106  may be greater than the disk width  102  and/or the sleeve thickness  98 . The outer surface  104  has a radius  108  that is greater than the radius  78  (see  FIG. 4 ). This radius  108 , for example, may be substantially equal to the radius  82  as illustrated in  FIGS. 2 and 3 . Alternatively, the radius  108  may be less than or greater than the radius  82 . In addition or alternatively, the radius  108  may be greater than a radius  110  of a radial outer surface  112  of the rotor seal element  64  as illustrated in  FIG. 2 . 
         [0044]    Referring to  FIGS. 2 and 3 , the rotor seal element  64 , the shield  58  and the inner race  70  are mounted on the shaft  44 ,  45 . The shield forward end  86  axially engages (e.g., contacts) the rotor seal element  64 . The shield aft end  88  axially engages the inner race  70 . The disk  92  therefore substantially blocks a line of sight (e.g., an axial line of sight) into the gap  84  as well as a line of sight (e.g., an axial line of sight) between the gap  84  and the rotor seal element  64 . 
         [0045]    The outer race  72  is connected to the stator  48 . The stator seal element  62  is connected to the seal support  60 , and circumscribes the shaft  44 ,  45 . The seal support  60  is connected to the stator  48 . The seal support  60  and the stator  48  may form an annular housing  114 . The housing  114  defines an annular chamber  116  into (e.g., through) which the shaft  44 ,  45  extends, and in which the seal elements  62  and  64 , the shield  58  and the bearing  46  are arranged. The seal support  60  biases the stator seal element  62  towards a seal surface  118  of the rotor seal element  64  that faces axially away from the bearing  46 . The stator seal element  62  therefore axially engages and fauns a seal with the rotor seal element  64 . Alternatively, as illustrated in  FIG. 6 , the seal surface  118  may face radially away from the inner race  70  and/or the bearing  46 . The stator seal element  62  therefore may radially engage and form a seal with the rotor seal element  64 . 
         [0046]      FIG. 7  illustrates the engine assembly  54  during a mode of engine operation where the seal elements  62  and  64  are exposed to relatively hot gas  120  within a plenum  122  located outside of the housing  114 . A portion of this gas  120  may be directed into passages  124  within the stator seal element  62  to provide a film of air (e.g., a buffer) and reduce wear between the seal elements  62  and  64 . Heat energy may be transferred from the gas  120  into the rotor seal element  64 . Concurrently, the bearing  46  may receive relatively cool lubrication fluid (e.g., oil) to lubricate and/or cool the races  70  and  72  as well as the bearing elements  74 . Various methods are known in the art for providing lubrication fluid to a bearing and therefore will not be discussed in further detail. A first portion  126  of the lubrication fluid may travel out of the bearing  46  in an axially aft and radially outward direction. A second portion  128  of the lubrication fluid may travel out of the gap  84  in an axially forward and radially outward direction. The disk  92  may substantially prevent some or all of the second portion  128  of the lubrication fluid from traveling towards (e.g., directly axially to) the rotor seal element  64 . The disk  92  therefore may significantly reduce the quantity of lubrication fluid that would otherwise contact and transfer heat energy out of the rotor seal element  64 . The rotor seal element  64  therefore may be subject to a relatively uniform temperature gradient, which may reduce coning of the rotor seal element  64 . 
         [0047]      FIG. 8  illustrates an alternate embodiment turbine engine assembly  130  for the engine  20  of  FIG. 1 . In contrast to the engine assembly  54  of  FIGS. 2 and 3 , the engine assembly  130  includes one or more spacers  132  and  134  (e.g., tubular sleeves) and an alternate embodiment shield  136 . The first spacer  132  is mounted on the shaft  44 ,  45  axially between the rotor seal element  64  and the shield  136 . The second spacer  134  is mounted on the shaft  44 ,  45  axially between the shield  136  and the inner race  70 . In contrast to the shield  58  of  FIGS. 2 and 3 , the shield  136  includes a disk  138  that extends radially between the shield inner surface  96  and the shield outer surface  104 . The surface  100  engages the first spacer  132 , and the second surface  100 ′ engages the second spacer  134 . 
         [0048]      FIG. 9  illustrates another alternate embodiment turbine engine assembly  140  for the engine  20  of  FIG. 1 . In contrast to the engine assembly of  FIGS. 2 and 3 , the engine assembly  140  includes a spacer  142  (e.g., a tubular sleeve) and an alternate embodiment shield  144  (e.g., a stator shield). The spacer  142  is mounted on the shaft  44 ,  45 , and axially engages the rotor seal element  64  and the inner race  70 . In contrast to the shield  58  of  FIGS. 2 and 3 , the shield  144  includes a base  146  that circumscribes an annular disk  148  (e.g., an annular flange), which may include one or more apertures  149  (e.g., drainage apertures) that extend axially through the disk  148 . The base  146  is connected to the stator  48 . The disk  148  extends axially between opposing surfaces  150 , thereby defining an axial disk width. The disk  148  extends radially inward from the base  146  to a shield inner surface  154 , thereby defining a radial disk thickness that may be greater than the disk width. The inner surface  154  has a radius  158  that is less than the radius  82  (see  FIG. 4 ) of the inner surface  80 . This radius  158 , for example, may be substantially equal to the radius  78  of the outer surface  76  as illustrated in  FIG. 9 . Alternatively, the radius  158  may be less than or greater than the radius  78 . 
         [0049]    The terms “forward”, “aft”, “inner” and “outer” are used to orientate the components of the engine assemblies  54 ,  130  and  140  described above relative to the turbine engine  20  and its axis  22 . A person of skill in the art will recognize, however, one or more of these components such as the shields  58 ,  136  and  144  may be utilized in other orientations than those described above. The shield  58 ,  136  or  144 , for example, may be arranged axially downstream of the inner race  70 . The present invention therefore is not limited to any particular engine assembly or shield spatial orientations. 
         [0050]    One or more of the foregoing engine assemblies and/or their components may have various configurations other than those illustrated in the drawings and described above. For example, a control gap may be defined between the stator seal element  62  and the rotor seal element  64 . The stator seal element  62  may be configured as a ring seal element. One of the elements  62 ,  64  may include one or more knife edge seals that radially and/or axially engage an (e.g., abradable) portion of the other one of the elements  64 ,  62 . The shield may also or alternatively be utilized to prevent lubrication fluid from directly contacting other components other than the rotor seal element. The shield may also or alternatively be configured, for example, to prevent lubrication oil from directly contacting temperature sensitive equipment such as telemetric electronics that may be housed within the chamber. The present invention therefore is not limited to any particular engine assembly or assembly component configurations. 
         [0051]    A person of skill in the art will recognize the foregoing engine assemblies may be included in various turbine engines other than the one described above. A person of skill in the art will also recognize the engine assemblies may be included in various types of rotational equipment other than a turbine engine. The present invention therefore is not limited to any particular types or configurations of rotational equipment. 
         [0052]    While various embodiments of the present invention have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. For example, the present invention as described herein includes several aspects and embodiments that include particular features. Although these features may be described individually, it is within the scope of the present invention that some or all of these features may be combined within any one of the aspects and remain within the scope of the invention. Accordingly, the present invention is not to be restricted except in light of the attached claims and their equivalents.