Abstract:
One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique gas turbine engine main engine rotor. Still another embodiment is a unique method for assembling a gas turbine engine main engine rotor. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and gas turbine rotors. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application 61/201,656, filed Dec. 31, 2009, and is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to gas turbine engines, and more particularly, to gas turbine engine rotors and the assembly and disassembly of gas turbine engine rotors. 
       BACKGROUND 
       [0003]    Gas turbine engine rotors remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology. 
       SUMMARY 
       [0004]    One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique gas turbine engine main engine rotor. Still another embodiment is a unique method for assembling a gas turbine engine main engine rotor. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and gas turbine engine rotor assemblies. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
           [0006]      FIG. 1  schematically illustrates a non-limiting example of a gas turbine engine in accordance with an embodiment of the present invention. 
           [0007]      FIG. 2  schematically illustrates aspects of a non-limiting example of a gas turbine engine rotor and a non-limiting example of a system for clamping rotor components together in accordance with an embodiment of the present invention. 
           [0008]      FIG. 3  is an enlarged view illustrating some features of the system of  FIG. 2 . 
           [0009]      FIG. 4  schematically illustrates a non-limiting example of additional features that may be employed in embodiments of the present invention. 
           [0010]      FIG. 5  schematically illustrates aspects of the gas turbine engine rotor and system of  FIG. 2  in a state of partial assembly. 
           [0011]      FIGS. 6A and 6B  schematically illustrate aspects of a non-limiting example of a gas turbine engine rotor and a non-limiting example of a system for clamping rotor components together. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the invention is intended by the illustration and description of certain embodiments of the invention. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present invention. Further, any other applications of the principles of the invention, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the invention pertains, are contemplated as being within the scope of the present invention. 
         [0013]    Referring now to the drawings, and in particular,  FIG. 1 , a non-limiting example of a gas turbine engine  10  in accordance with an embodiment of the present invention is schematically depicted. In one form, gas turbine engine  10  is an axial flow machine, e.g., an air-vehicle power plant. In other embodiments, gas turbine engine  10  may be a radial flow machine or a combination axial-radial flow machine. Embodiments of the present invention include various gas turbine engine configurations, for example, including turbojet engines, turbofan engines, turboprop engines, and turboshaft engines having axial, centrifugal and/or axi-centrifugal compressors and/or turbines. 
         [0014]    In one form, gas turbine engine  10  includes a compressor  12  having a compressor rotor  14 ; a diffuser  16 ; a combustion system  18 ; a turbine  20  having a turbine rotor  22 ; and a shaft  24  coupling compressor rotor  14  with turbine rotor  22 . Combustion system  18  is in fluid communication with compressor  12  and turbine  20 . Turbine rotor  22  is drivingly coupled to compressor rotor  14  via shaft  24 . Compressor rotor  14 , turbine rotor  22  and shaft  24  form a main engine rotor  26 , which rotates about an engine centerline  28 . Although only a single spool is depicted, it will be understood that embodiments of the present invention include both single-spool and multi-spool engines. The number of blades and vanes, and the number of stages thereof of compressor  12  and turbine  20  may vary with the application, e.g., the efficiency and power output requirements of a particular installation of gas turbine engine  10 . In various embodiments, gas turbine engine  10  may include one or more fans, additional compressors and/or additional turbines. 
         [0015]    During the operation of gas turbine engine  10 , air is received at the inlet of compressor  12  and compressed. After having been compressed, the air is supplied to diffuser  16 , which reduces the velocity of the pressurized air discharged from compressor  12 . The pressurized air exiting diffuser  16  is mixed with fuel and combusted in combustion system  18 . The hot gases exiting combustion system  18  are directed into turbine  20 . Turbine  20  extracts energy from the hot gases to, among other things, generate mechanical shaft power to drive compressor  12  via shaft  24 . In one form, the hot gases exiting turbine  20  are directed into a nozzle (not shown), which provides thrust output for gas turbine engine  10 . In other embodiments, additional compressor and/or turbine stages in one or more additional rotors upstream and/or downstream of compressor  12  and/or turbine  20  may be employed, e.g., in single or multi-spool gas turbine engines. 
         [0016]    Referring now to  FIG. 2 , a non-limiting example of a system  30  for clamping together components of main engine rotor  26  is schematically depicted in accordance with an embodiment of the present invention. In the present example, turbine rotor  22  includes a stub shaft  32 . In other embodiments, stub shaft  32  may be formed separately and affixed to turbine rotor  22 . System  30  is operative to clamp shaft  24  and stub shaft  32 . In one form, stub shaft  32  is integral with turbine rotor  22 . System  30  retains turbine rotor  22  and shaft  24  in a coupled arrangement. A splined interface  34  between stub shaft  32  and shaft  24  transmits torque between turbine rotor  22  and shaft  24 . 
         [0017]    System  30  includes a compression washer  36  and a retaining ring  38  positioned in such a way that a preload is maintained between the turbine rotor  22  and shaft  24  during engine  10  operation. The preload is maintained by compression washer  36 , which is placed into a state of compression during the assembly of turbine rotor  22  and shaft  24 . Use of the term, “compression” in the present context indicates that compression washer  36  is compressed in the sense that a spring is compressed, and is not necessarily reflective of the stress field within compression washer  36 . In one form, compression washer  36  is a conical compression washer, otherwise known as, for example, a Bellville spring, a Bellville washer or a disk spring. It will be understood that the shape of compression washer  36  is not limited to being conical; rather, any suitable shape may be employed in various embodiments. In one form, retaining ring  38  is a split retaining ring. In other embodiments, other retaining ring types may be employed, for example, spiral retaining rings. 
         [0018]    Referring now to  FIG. 3 , an enlarged view of system  30  is depicted with turbine rotor  22  and shaft  24  in the assembled state. Each component of rotor  26  that is clamped together with system  30  includes a face through which loads to/from compression washer  36  are transferred into the component. In the depicted example, shaft  24  includes a face  40 , and stub shaft  32  of turbine rotor  22  includes a face  42  opposite face  40 , through which loads to and from compression washer  36  are transferred into the respective shaft  24  and turbine rotor  22 . Compression washer  36  mechanically loads face  40  against face  42 . In some embodiments, an intervening component, such as a spacer or another component, may be placed between compression washer  36  and either or both of face  40  and face  42 . 
         [0019]    Each component of rotor  26  that is clamped together with system  30  also includes another face for reacting the compression washer  36  loads with retaining ring  38 . In one form, the other face is part of an opening in each component that receives therein retaining ring  38 . In the depicted example, shaft  24  includes a shouldered channel  44 , and stub shaft  32  includes a shouldered channel  46 . Channels  44  and  46  are configured to receive retaining ring  38 . In one form, channels  44  and  46  extend circumferentially around a respective inside or outside diameter of each component. In one example, the channels are circumferentially continuous. In other embodiments, discontinuous or interrupted channels may be employed. In one form, channel  44  is a groove, e.g., a circumferential slot, and channel  46  is also a groove. Groove  44  includes a face  48 , and groove  46  includes a face  50  that faces opposite face  48 . Faces  48  and  50  react the compression washer  36  loads through retaining ring  38 , which loads retaining ring  38  in shear. Faces  40  and  42 , and grooves  44  and  46 , or more particularly, faces  48  and  50  of respective grooves  44  and  46 , are positioned so that compression washer  36  is in a state of compression between face  40  and face  42  when retaining ring  38  is positioned in both groove  44  and groove  46 , or more particularly, when retaining ring  38  is positioned between faces  48  and  50 . In other embodiments, other types of channels in addition to or in place of grooves may be employed, so long as those channels include opposing faces such as faces  48  and  50  to react the compression washer  36  loads through retaining ring  38 . 
         [0020]    In one form, at assembly, retaining ring  38  is displaced inward into groove  44 , and once assembled, retaining ring  38  is displaced radially outward and expanded into groove  46 , which locks shaft  24  and turbine rotor  22  together axially. Faces  40  and  42 , and compression washer  36  are positioned such that when retaining ring  38  is in the expanded state, occupying both grooves  44  and  46  between faces  48  and  50 , conical compression washer  36  is in a compressed state. Loads from the compressed compression washer  36  tend to drive shaft  24  and turbine rotor  22  axially apart, which is prevented by retaining ring  38 . In one form, the force exerted by compression washer  36  is selected to provide a preload on the mated components during all operating conditions of engine  10 . The force is based primarily on the spring characteristics of compression washer  36 , the axial dimensions of compression washer  36  and retaining ring  38 , and the locations of faces  40 ,  42 ,  48  and  50 . In other embodiments, the force exerted by compression washer  36  may be selected to maintain a preload only under some engine  10  operating conditions. 
         [0021]    Referring now to  FIG. 4 , a non-limiting example of some additional features that may be included in various embodiments of system  30  is depicted. Additional features may include, for example, a spring  52  disposed adjacent to retaining ring  38 . Spring  52  is operative to provide a load to retaining ring  38  in order to assist retaining ring  38  in expanding from groove  44  into groove  46 . In other embodiments, spring  52  may be operative to assist retaining ring in collapsing from groove  46  into groove  44 . In one form, spring  52  is a circumferential wave washer. In other embodiments, other types of springs may be employed. 
         [0022]    Additional features may also include one or more openings in one or both components of rotor  26  to facilitate the assembly and/or disassembly of rotor  26  components. In the embodiment of  FIG. 4 , stub shaft  32  of turbine rotor  22  includes a plurality of openings in the form of holes  54 . Holes  54  are configured to receive a tool  56 , such as one or more tooling pins. Tool  56  may be used to compress retaining ring  38  (and spring  52  for those embodiments that employ spring  52 ) so that turbine rotor  22  may be removed from shaft  24 . In other embodiments, shaft  24  may include openings such as holes  54  to aid in expanding retaining ring  38  using a tool such as tool  56 . In various embodiments, either or both components of rotor  26  may include openings such as holes  54  to aid in compressing and/or expanding retaining ring  38  to aid in the assembly and/or disassembly of rotor  26 . 
         [0023]    The assembly and disassembly of rotor components such as turbine rotor  22  and shaft  24  may be accomplished in more than one manner. In one form, assembly may include positioning compression washer  36  between face  40  of shaft  24  and face  42  of stub shaft  32  of turbine rotor  22 ; positioning retaining ring  38  in groove  44 ; assembling stub shaft  32  of turbine rotor  22  onto shaft  24 ; applying a clamp load to force compression washer  36  into a state of compression between face  40  of shaft  24  and face  42  of stub shaft  32  of turbine rotor  22 ; and displacing retaining ring  38  so that retaining ring  38  is positioned in both grooves  44  and  46 . The displacement of retaining ring  38  may include self-displacement from a compressed state, and/or forced displacement. Other assembly steps in addition to or in place of those described herein may likewise be employed. 
         [0024]    Disassembly of turbine rotor  22  from shaft  24  may be performed by repositioning retaining ring  38  from being in both groove  44  and groove  46  to being in only one of groove  44  and groove  46 , and by removing sliding turbine rotor  22  off of shaft  24 . In the illustrated embodiment, retaining ring  38  is displaced from groove  46  into groove  44  in order to disassemble rotor  36 . In other embodiments, retaining ring  38  may be displaced from groove  44  into groove  46  in order to disassembly rotor  36 . In either case, a tool such as tool  56  may be inserted into an opening such as hole  54  and be used to apply force to retaining ring  38  in order to displace retaining ring  38  to disassemble rotor  36 . 
         [0025]    Referring now to  FIG. 5 , a convenient method of assembling turbine rotor  22  and shaft  24  is described. In one form, assembly is accomplished by first installing retaining ring  38  in groove  44  in shaft  24 . Next, retaining ring  38  is compressed, and compression washer  36  is installed atop retaining ring  38 . This displaces the retaining ring  38  into groove  44 , and allows the forward edge of stub shaft  32  to pass over retaining ring  38 . In some embodiments, stub shaft  32  is heated to expand the pilot diameters thereby eliminating any interference at the mating surfaces. Likewise, in some embodiments shaft  24  is cooled. Stub shaft  32  is then slid onto shaft  24 , engaging drive splines  34 . As turbine rotor  22  is further engaged, the forward edge of the stub shaft  32  displaces compression washer  36  off of retaining ring  38 . A chamfer  58  on the inner edge of stub shaft  32  allows stub shaft  32  to pass smoothly over retaining ring  38 . An axial clamping load is then applied between turbine rotor  22  and shaft  24 , rotor displacing compression washer  36  until groove  46  in stub shaft  32  shaft aligns with retaining ring  38 . With the components thus aligned, retaining ring  38  expands outward into groove  46  of stub shaft  32 . The assembly of shaft  24  and turbine rotor  22  is now complete. In embodiments that employ spring  52 , spring  52  assists retaining ring  38  in expanding into groove  46 . In some embodiments, no special tooling is required to join the mating parts. 
         [0026]    Disassembly is accomplished by first applying an axial clamp load to the mated components such that the preload is removed from retaining ring  38 . Tool  56  is then employed via holes  54  to reposition retaining ring  38  out of groove  46  and further into groove  44 . Displacing retaining ring  38  inward with the tooling pins allows stub shaft  32  to disengage from shaft  24 . In other embodiments, other types of tools may be employed to disassemble rotor  26 . 
         [0027]    In the depiction of  FIGS. 2-5  aspects of the present invention are illustrated and described relative to assembling a shaft to a rotor. Embodiments of the present invention are equally applicable to other rotor assembly configurations, such as for clamping together rotor disks and/or spacers of a turbine rotor or compressor rotor. 
         [0028]    For example, referring now to  FIGS. 6A and 6B , a non-limiting example of a four stage compressor rotor  60  in accordance with an embodiment of the present invention is depicted. Rotor  60  includes four disks  62 , three of which include an integral spacer  64 . In other embodiments, spacers  64  may be separately formed and attached to disks  62  using any convenient method, such as that described herein. In the embodiment of  FIGS. 6A and 6B , a system  70  for clamping components of compressor rotor  60  together includes a compression washer  72  and a retaining ring  74 . 
         [0029]    Similar to the embodiments described in  FIG. 2-5 , compression washer  72  is disposed between opposite faces  76  and  78  of the mating adjacent components; and retaining ring  74  is disposed in opposite channels  80  and  82  with opposite faces  84  and  86 . As with the embodiment of  FIGS. 2-5 , compression washer  72  and a retaining ring  74  are positioned in such a way that a preload is maintained between each adjacent disk/spacer during engine operation. The preload is generated by compression washer  72 , which is placed into a state of compression during the assembly of rotor  60  in a manner similar to that set forth above with respect to rotor  26 . Faces  76  and  78 , and channels  80  and  82 , or more particularly, faces  84  and  86 , are positioned so that compression washer  72  is in a state of compression between faces  76  and  78  when retaining ring  74  is positioned in both of channels  80  and  82 , or more particularly, when retaining ring  74  is positioned between faces  84  and  86 . The assembly and disassembly of rotor  60  may be performed similarly to that described above with respect to the embodiment of  FIGS. 2-5 . Torque may be transmitted between each disk/spacer by means (not shown), such as splines, pins or keys, for example. 
         [0030]    In addition to the above, embodiments of the present invention include similar systems having compression washers, retaining rings, and two groups of two opposing faces that may be used to assemble static components, such as engine case structures, without the use of threaded joints or threaded fasteners. 
         [0031]    Embodiments of the present invention include a gas turbine engine, comprising: a main engine rotor having a first rotor component and a second rotor component, wherein the first rotor component includes a first face and a first channel; and wherein the second rotor component includes a second face and a second channel; a compression washer disposed between the first face and the second face, wherein the compression washer is operative to mechanically load the first face against the second face; and a retaining ring, wherein the first face, the first channel, the second face and the second channel are positioned so that the compression washer is in a state of compression between the first face and the second face when the retaining ring is positioned in both the first channel and the second channel; and wherein the retaining ring reacts the mechanical loading produced by the compression of the compression washer. 
         [0032]    In a refinement, the main engine rotor includes a turbine rotor and a compressor rotor, and wherein the first rotor component is one of the turbine rotor and the compressor rotor. 
         [0033]    In another refinement, the main engine rotor includes a shaft operative to transmit power from the turbine rotor to drive the compressor rotor, and wherein the second rotor component is the shaft. 
         [0034]    In yet another refinement, the compressor rotor includes a plurality of compressor stages, and wherein the first rotor component is a first compressor stage and wherein the second rotor component is a second compressor stage. 
         [0035]    In still another refinement, at least one of the first rotor component and the second rotor component includes an opening extending into the respective at least one of the first channel and the second channel. 
         [0036]    In yet still another refinement, the opening is structured to admit a tool therein for displacement of the retaining ring. 
         [0037]    In a further refinement, the engine includes a spring disposed in one of the first channel and the second channel, wherein the spring is positioned to place a spring load on the retaining ring. 
         [0038]    In a yet further refinement, the spring is a circumferential wave washer. 
         [0039]    Embodiments include a method for assembly and disassembly of a main engine rotor of a gas turbine engine, comprising: positioning a compression washer between at least one of a first face of a first rotor component of the main engine rotor and a second face of a second rotor component of the main engine rotor; positioning a retaining ring in one of a first groove of the first rotor component and a second groove of the second rotor component; assembling the first rotor component to the second rotor component; applying a clamp load to force the compression washer into a state of compression between the first face and the second face; and displacing the retaining ring so that the retaining ring is positioned in both the first groove and the second groove. 
         [0040]    In a refinement, the method further includes releasing the clamp load, wherein the retaining ring reacts the compression of the compression washer and retains the first rotor component in assembly with the second rotor component. 
         [0041]    In another refinement, the first rotor component is clamped to the second rotor component without the use of threads. 
         [0042]    In yet another refinement, the method also includes disassembling the first rotor component from the second rotor component by repositioning the retaining ring from being in both the first groove and the second groove to being in the one of the first groove and the second groove, and removing the first rotor component from the second rotor component. 
         [0043]    In still another refinement, the repositioning of the retaining ring includes inserting a tool into an opening in one of the first groove and the second groove, and applying force to the retaining ring using the tool to displace the retaining ring. 
         [0044]    In yet still another refinement, the method includes positioning a spring in one of the first groove and the second groove, wherein the spring is positioned to place a spring load on the retaining ring. 
         [0045]    In a further refinement, the main engine rotor includes a shaft operative to transmit power from a turbine rotor to drive a compressor rotor, and wherein one of the first rotor component and the second rotor component is the shaft. 
         [0046]    In a yet further refinement, the main engine rotor includes a plurality of compressor stages, and wherein the first rotor component is one compressor stage and wherein the second rotor component is an other compressor stage. 
         [0047]    In a still further refinement, the main engine rotor includes a compressor disk and a compressor spacer, and wherein the first rotor component is the disk and wherein the second rotor component is the spacer. 
         [0048]    Embodiments of the present invention include a system, comprising: a first component having a first face and a second face; a second component having a third face and a fourth face, wherein the third face is opposite the first face, and wherein the fourth face is opposite the third face; a compression washer disposed between the first face and the third face, wherein the compression washer is operative to mechanically load the first face against the third face; and a retaining ring, wherein the first face, the second face, the third face and the fourth face are positioned so that the compression washer is in a state of compression between the first face and the third face when the retaining ring is positioned between the second face and the fourth face; and wherein the retaining ring reacts the mechanical loading produced by the compression of the compression washer. 
         [0049]    Embodiments of the present invention include a gas turbine engine main engine rotor, comprising: a first rotor component; a second rotor component; and means for clamping the first rotor component to the second rotor component. 
         [0050]    In a refinement, the means for clamping includes a compression washer and a split retaining ring that jointly clamp together the first rotor component and the second rotor component. 
         [0051]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.