Abstract:
A seal assembly for a gas turbine engine, may be manufactured in two pieces, the first piece is a seal plate with a cavity around its inner wall and the second piece is a sleeve that mounts in the cavity of the seal plate. The sleeve may have oil distribution channels that deliver oil to subsequent components and apertures that deliver oil to the seal plate. The volume of oil delivered to the seal plate can be set by the number of apertures and related radial holes in the sleeve. Because the sleeve delivers oil through the apertures and radial holes to an annulus in the cavity of the seal plate, cooling bores in the seal plate need only be drilled into the annulus and the number of cooling bores can be independent of the number of radial holes in the sleeve.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This Application is a non-provisional patent application claiming priority under 35 U.S.C. §119(e) to US Provisional Patent Application Ser. No. 61/911,161 filed on Dec. 3, 2013. 
    
    
     FIELD OF THE DISCLOSURE 
     The subject matter of the present disclosure generally relates to gas turbine engines. More particularly, the subject matter of the current disclosure relates to a two-piece seal plate of a gas turbine engine. 
     BACKGROUND OF THE DISCLOSURE 
     Seal plates in gear assemblies or elsewhere in gas turbine engines have numerous functions. First, seal plates act as a seal between a shaft and bearing, for example, in a bull gear. Seal plates can also act to distribute oil thrown outward during rotation of the shaft for both cooling and lubrication. In some cases, a seal plate has an annulus connected to slots to allow oil to pool and be distributed in different proportions to components coupled to the seal plate. Lastly, the seal stands inline in the engine component stack as one of the load bearing elements in the stack. 
     However, design pressures continue to limit the space available for prior art implementations of seal plates. Many parts simply need to be smaller, which limits the use of prior art oil distribution techniques for many of the following reasons. Smaller components may make the seals more susceptible to uneven thermal expansion when oil cooling passages are widely spaced in some prior embodiments. The need for more even cooling to minimize these expansion effects leads to increased holes and slots in the seal plates for oil flow. This has at least two effects: One, precise manufacturing controls are required for drilling cooling holes through the seal plates into the oil distribution slots of the inner wall of the seal. Two, the increased number of cooling passages and slots reduces the mechanical strength of the seal to bear the loads of the engine component stack. 
     Further, seals used in different applications may have slightly different requirements for cooling and oil flow distribution. This leads to increased inventory and more customization in the manufacturing processes for different engines. 
     SUMMARY OF THE DISCLOSURE 
     In an aspect of the disclosure, a seal assembly for use in a gas turbine engine may include a seal plate and a sleeve. The seal plate may include an inner wall having an annulus formed therein and a plurality of bores between an outer wall of the seal plate and the annulus. The sleeve may be disposed in the annulus of the seal plate. The sleeve may have a cylindrical shape with an inner wall, an outer wall, a front edge, and a rear edge. The sleeve may also have a front annulus around the inner wall adjacent the front edge, a rear annulus around the inner wall at the rear edge, a dam between the front annulus and the rear annulus formed by a ridge between the front and rear annuli, and a plurality of channels disposed axially in the dam between the front annulus and the rear annulus. The sleeve may also include a plurality of radial holes in the dam and a plurality of apertures disposed axially in the dam from the front annulus to respective radial holes. 
     In another aspect of the disclosure, a sleeve having a generally cylindrical shape for use in a seal assembly of a gas turbine engine may include an outer surface, an inner surface, a front edge, and a rear edge. The sleeve may be disposed in the seal plate of a seal assembly. The sleeve may also include a front annulus disposed around the inner surface adjacent the front edge, a rear annulus disposed around the inner surface at the rear edge and a dam between the front annulus and the rear annulus formed by a ridge between the front and rear annuli. The sleeve may also have an aperture disposed axially in the dam from the front annulus to a radial hole connecting the slot and the outer surface. 
     In yet another aspect of the disclosure, a method of distributing oil in a gas turbine engine may include providing a seal plate, disposing a sleeve at an inner wall of the seal plate, the sleeve having an axial oil path and a radial oil path. The method may include rotating the sleeve and the seal plate during operation of the gas turbine engine. The method may include providing oil at an inner wall of the sleeve and moving the oil through the axial oil path to an adjoining component of the gas turbine engine as a result of rotating the sleeve and seal plate. The method may also include moving the oil through the radial oil path of the sleeve to an annulus of the seal plate. The annulus of the seal plate may be located between an outer wall of the sleeve and the inner wall of the seal plate. The method may also include moving oil through a bore disposed between the annulus of the seal plate and an outer wall of the seal plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited concepts of the present disclosure may be understood in detail, a more particular description is provided by reference to the embodiments which are illustrated in the accompanying drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments and are therefore not to be considered limiting of its scope, for the concepts of the present disclosure may admit to other equally effective embodiments. Moreover, the drawings are not necessarily to scale, emphasis generally being placed upon illustrating the principles of certain embodiments. 
       Thus, for further understanding of these concepts and embodiments, reference may be made to the following detailed description, read in connection with the drawings in which: 
         FIG. 1  is a section view of a prior art seal plate; 
         FIG. 2  is a section view of a seal assembly in accordance with the current disclosure; 
         FIG. 3  is a another section view of the seal assembly of  FIG. 2 ; 
         FIG. 4  is a plan view of the seal assembly of  FIG. 2 ; 
         FIG. 5  a flow chart of a method of distributing oil using a seal assembly. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a section view of a prior art seal plate  10 . The seal plate  10  may include axial oil passages  12  that direct oil to an adjacent component, such as a bearing (not depicted) and radial holes  14  that direct oil up through the seal plate  10  to cool the seal plate  10 . As discussed above, when the spacing between the radial holes  14  are spaced too far apart, the seal plate  10  can heat unevenly causing the seal plate  10  to distort. The number of axial oil passages  12  to radial holes  14  sets the ratio of oil that will be delivered to the bearing versus cooling the seal. Because this ratio may change from application to application, a large number of seal plates must be manufactured to accommodate each different application. 
     The number of radial holes  14  can be increased to meet cooling and distortion requirements for the seal plate  10 . However, when the number of radial holes  14  and their associated apertures  16 , are increased, in combination with the axial oil passages  12 , the physical integrity of the seal plate  10  can suffer when placed under high loads when the rotating engine stack is assembled or in operation. 
     Lastly, the process for creating the radial hole  14  requires precise measurements so that when the hole is drilled, it actually contacts the aperture  16 . 
       FIG. 2  illustrates a section view of a seal assembly  100  that may be used in a gas turbine engine  101  (see  FIG. 4 ). The seal assembly  100  includes a seal plate  102  and a sleeve  104 . The seal plate  102  may include an annulus  106  and a bore  108  that connects the annulus  106  to an outer wall  130  of the seal plate  102 . A dam  109  formed by the annulus  106  allows oil to accumulate or pool to help even distribution of oil to bore  108  and other similar bores used to cool the seal plate  102 . 
     The sleeve  104  may include a first annulus  110  at a front edge  111  of the sleeve  104 . The sleeve  104  may also include a second annulus  112  at a rear edge  113  of the sleeve  104 . A dam  114  may be formed between the first annulus  110  and the second annulus  112 . The dam  114  may include a channel or at least one channel  116  that axially connect the first annulus  110  to the second annulus  112 . 
     An aperture  118  connects the first annulus  110  to a radial hole  120  in the sleeve  104 . Unlike the channel  116 , the aperture  118  does not connect the first annulus  110  to the second annulus  112 . Instead, the aperture  118  connects the first annulus  110  to the radial hole  120 . 
     The channel  116  and aperture  118  may be tapered slightly to encourage the flow of oil axially. The dam  114  allows oil to accumulate or pool in the first annulus  110  to help to ensure even distribution of oil through the channel  116  and the aperture  118 . 
     As illustrated, there may be a number of channels  116  and apertures  118  with corresponding radial holes  120 . The number of channels  116  affects the amount of oil that is moved to an adjacent component, such as a bearing. The number of apertures  118  affects the amount of oil that is moved to the seal plate  102  for cooling via the bores  108 . The number of channels  116  and apertures  118  may be selected to obtain the desired ratio of flow to the seal plate  102  and a component located adjacent to the second annulus  112 . 
     In terms of manufacturing, the relatively short length of the radial hole  120  makes the alignment of a tool (not depicted) creating the radial hole  120  with the aperture  118  much simpler. In some cases, the short length of the bit needed to make the radial hole  120  may allow the radial hole  120  to be drilled from inside the sleeve  104 , making alignment with the aperture  118  extremely straightforward. Similarly, because the bore  108  can penetrate anywhere in the annulus  106 , manufacturing of the seal plate  102  is greatly simplified over the prior art seal plate  10 , which required precise alignment of the radial hole  14  with the aperture  16 . 
     Further, because the number of bores  108  is independent of the number of radial holes  120 , the seal plate  102  can be designed to meet its cooling requirement independently from the design of the sleeve  104 . That is, the number of bores  108  is not a function of the number of radial holes  120  in the sleeve  104 . Similarly, the ratio of channels  116  to apertures  118 /radial holes  120  is independent of the number of bores  108 . Thus, the overall number of stocking kits for sleeves  104  and seal plates  102  may be reduced, compared to the integral unit of  FIG. 1 . 
     Due to the manner in which the seal plate  102  is constructed and how the sleeve  104  fits inside the seal plate  102 , the sleeve  104  is not load bearing with respect to a component stack of engine components that includes the seal plate  102 . This allows the sleeve  104  to have more channels  116  and apertures  118 /radial holes  120  than would be possible if these structures had to be accommodated in a prior art unitary seal plate  10 . 
       FIG. 3  is another section view of the seal assembly  100 . The section view of  FIG. 3  illustrates a tab  124  of the sleeve  104  that is inserted into a slot  126  of the seal plate  102 . The tab  124  and slot  126  arrangement may be part of a press-fit assembly process to hold the elements of the seal assembly  100  together and to cause the sleeve  104  to rotate in unison with the seal plate  102  while the gas turbine engine  101  is operating. The sleeve  104  may further comprise one or more tabs  124  configured to engage a corresponding one or more slots  126  in an adjoining component of the seal assembly. The one or more tabs  124  may be disposed on the front edge of the sleeve  104 . 
       FIG. 4  is a cross section of the seal assembly  100 . The seal assembly  100  may include seals  122  and  123  to provide a tight radial fit between the sleeve  104  and the seal plate  102 . The seals  122  and  123  may minimize unbalance, vibration, fretting, etc., to encourage uniform rotation with the seal plate and shaft, in combination with the tab  124  and slot  126 . The seals  122  and  123  or at least one seal may be located at distal portions of the annulus  106  and between an inner wall  132  of the sleeve  104  and an outer wall  134  of the seal plate  102 .  FIG. 4  also illustrates an inner wall  136  of the sleeve  104 . Oil may be supplied by conduit  138  in another adjacent component, such as a shaft. Oil that reaches the second annulus  112  via the channels  116  may flow out of the second annulus  112  through an opening  128  in an adjacent component, such as a bearing. 
       FIG. 5  is a flow chart of a method  200  of distributing oil in a gas turbine engine  101  using a seal assembly  100  including a seal plate  102  and a sleeve  104 . At a block  202 , the seal plate  102  may be provided. At a block  204 , the sleeve  104  may be disposed at an inner wall  132  of the seal plate  102 . The sleeve  104  may have an axial oil path  116  and a radial oil path  120 . At a block  206 , the seal assembly  100  may be rotated during operation of the gas turbine engine. The rotation may, among other effects, cause oil to move through the seal assembly  100 . In an embodiment, the seal plate  102  and sleeve  104  may be coupled so that the seal plate  102  and the sleeve  104  move in unison. 
     At a block  208 , oil may be provided at an inner wall  136  or an annulus  110  of the sleeve  104 . In an embodiment, the oil may be provided via a conduit  138  in a component of the gas turbine engine. At a block  210 , the rotation may also cause oil to move through the axial oil path  116  to an adjoining component of the gas turbine engine  101 , such as a bearing. 
     At a block  212 , the rotation may cause oil to move through the radial oil path  120  of the sleeve  104  to an annulus  106  of the seal plate  102 . The annulus  106  of the seal plate  102  may be located between an outer wall  134  of the sleeve  104  and the inner wall  132  of the seal plate  102 . 
     At a block  214 , oil may be moved by the rotation of the seal assembly  100  through a bore  108  disposed between the annulus  106  of the seal plate  102  and an outer wall  130  of the seal plate  102 . The oil moving through the bore  108  may provide cooling to the seal plate  102 . In an embodiment, there may be a plurality of axial oil paths  116 , radial oil paths  120 , and bores  108 , although the number of bores  108  in the seal plate  102  can be independent of the number of radial oil paths  120  in the sleeve  104 . 
     While the present disclosure has shown and described details of exemplary embodiments, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the disclosure as defined by claims that may be supported by the written description and drawings. Further, where these exemplary embodiments (and other related derivations) are described with reference to a certain number of elements it will be understood that other exemplary embodiments may be practiced utilizing either less than or more than the certain number of elements.