Abstract:
A turbine assembly is provided. The turbine assembly includes a turbocharger drive having a first threaded portion and a turbine wheel assembly. The turbine wheel assembly includes a turbine wheel and a second threaded portion adapted to engage the first threaded portion of the turbocharger drive. The turbine assembly may be utilized in a turbocharger assembly, wherein a compressor is connected to a second end of the turbocharger drive.

Description:
U.S. GOVERNMENT RIGHTS  
       [0001]     This invention was made with government support under the terms of Contract No. DE-SC05-00OR-22810 awarded by the Department of Energy. The government may have certain rights in this invention. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention is directed to a turbocharger assembly and, more particularly, to a turbocharger assembly that provides for removably connecting a turbine wheel assembly to a turbocharger drive.  
       BACKGROUND  
       [0003]     Internal combustion engines such as, for example, diesel engines, gasoline engines, or natural gas engines may be operated to generate a power output. In order to maximize the power generated by the internal combustion engine, the engine may be equipped with a turbocharged air induction system.  
         [0004]     A turbocharged air induction system may include a turbocharger that compresses the air flowing into the engine to thereby force more air into a combustion chamber. The increased supply of air allows for increased fuelling, which may result in increased power. A turbocharged engine typically produces more power than the same engine without turbocharging.  
         [0005]     A turbocharger may include a turbine wheel that is connected to a compressor. The expansion of hot exhaust gases over the turbine wheel drives the compressor wheel to force compressed air into a combustion chamber. A typical turbocharger includes a housing, a shaft, a turbine wheel attached to one end of the shaft, and a compressor connected by threaded fastening to the other end of the shaft. The turbine, shaft, and compressor may be assembled into the housing as described in U.S. Pat. No. 5,193,989 issued to Fleury et al. on Mar. 16, 1993. The &#39;989 patent to Fleury et al. describes assembly of a turbocharger having the turbine wheel permanently attached to the shaft. The shaft and turbine wheel may be inserted from one side of the housing and the compressor wheel may be fastened to the other end of the shaft.  
         [0006]     However, the turbocharger of Fleury et al. does not allow for the design flexibility required for more complex turbocharging systems that require additional components. Adding the additional components to the turbocharger systems of Fluery et al. may be difficult because the turbocharger components may only be assembled from one end of the turbocharger shaft. Additionally, the turbocharger of Fleury et al. may be too expensive to maintain when combined with more complex air induction systems because the turbine wheel and shaft are inseparable.  
         [0007]     The turbocharger assembly of the present invention solves one or more of the problems set forth above.  
       SUMMARY OF THE INVENTION  
       [0008]     A first aspect of the present disclosure is directed to a turbine assembly. The turbine assembly includes a turbocharger drive having a first threaded portion and a turbine wheel assembly. The turbine wheel assembly includes a turbine wheel and a second threaded portion adapted to engage the first threaded portion of the turbocharger drive.  
         [0009]     A second aspect of the present disclosure is directed to a method of assembling a turbocharger. The method includes inserting a drive into a main housing, wherein the turbocharger drive includes a first end having a first threaded portion and a second end. A second threaded portion of a turbine wheel assembly is engaged with the first threaded portion of the turbocharger drive. A compressor is connected to the second end of the turbocharger drive.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a cross-sectional illustration of a turbine assembly in accordance with an exemplary embodiment of the present invention.  
         [0011]      FIG. 2  is a cross-sectional illustration of a turbine assembly in accordance with an exemplary embodiment of the present invention.  
         [0012]      FIG. 3  is a cross-sectional illustration of a turbocharger in accordance with an exemplary embodiment of the present invention.  
         [0013]      FIG. 4  is a diagrammatic and schematic illustration of an engine system in accordance with an exemplary embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0014]     An exemplary embodiment of a turbine wheel assembly  10  is illustrated in  FIG. 1 . The turbine wheel assembly  10  includes a turbine wheel  11  having a turbine wheel base  12  and a plurality of turbine blades  13 . The plurality of turbine blades  13  may be disposed on the outer periphery of the turbine wheel base  12  and may be adapted to rotate the turbine wheel base  12  when driven by the expansion of hot exhaust gases. The plurality of turbine blades  13  may be rigidly fixed to the turbine wheel base  12  using conventional means or they may be movable with respect to the turbine wheel base  12  such as, for example, by providing variable pitch turbine blades or variable geometry turbine blades. The plurality of turbine blades  13  may also be integral with the turbine wheel base  12 .  
         [0015]     The turbine wheel assembly  10  may also include a connecting means such as for example, a threaded portion  14 . The threaded portion  14  may be integral to turbine wheel base  12  or may be connected to the base through any means known in the art such as, for example, inertia welding. The threaded portion  14  may be adapted to transmit power from the turbine wheel assembly  10  to a corresponding connecting member.  
         [0016]     In the embodiment of  FIG. 1 , the threaded portion  14  of the turbine wheel assembly  10  is adapted to engage a corresponding connecting means of a turbocharger drive  18 . In this embodiment, the connecting means is a threaded portion  16 . When the threaded portion  14  of the turbine wheel assembly  10  is engaged with the threaded portion  16  of the turbocharger drive  18 , the turbine wheel assembly  10  is connected to the turbocharger drive  18  so that a rotation of the turbine wheel assembly  10  will cause a corresponding rotation of the turbocharger drive  18 .  
         [0017]     In the exemplary embodiment of  FIG. 1 , the threaded portion  14  of turbine wheel assembly  10  has male threads and the threaded portion  16  of the turbocharger drive  18  has female threads. The male threads of the turbine wheel assembly  10  may be engaged with the female threads to connect the turbine wheel assembly  10  to the turbocharger drive  18 . The turbine wheel assembly  10  may alternatively have a female threaded portion adapted to engage a male threaded portion of the turbocharger drive  18 .  
         [0018]     Another exemplary embodiment of a turbine wheel assembly  10  is illustrated in  FIG. 2 . The turbine wheel assembly  10  of this embodiment includes a turbine wheel  11  and a stub shaft  20  having a threaded portion  22 . The stub shaft  20  may be integral to turbine wheel base  12  or may be connected to turbine wheel base  12  by any manner known in the art such as, for example, inertia welding. The stub shaft  20  may include a female threaded portion  22  adapted to engage a male threaded portion  16  located on the turbocharger drive  18  (referring to  FIG. 1 ), thereby connecting the turbine wheel assembly  10  to the turbocharger drive  18 . Alternatively, the stub shaft  20  may include a male threaded portion adapted to engage a female threaded portion located on the turbocharger drive  18 .  
         [0019]     It is contemplated that the turbine wheel assembly  10  may be incorporated in a turbocharger assembly. An exemplary embodiment of a turbocharger  23  is illustrated in  FIG. 3 . In this embodiment, the turbocharger  23  includes a stator housing  24  in which a pre-assembled drive assembly  26  may be inserted.  
         [0020]     The pre-assembled drive assembly  26  may have a stator  28  and a rotor  29  held by end plate retainers  34  between bearings  30 . The stator  28 , rotor  29 , end plate retainers  34 , and bearings  30  are assembled to the turbocharger drive  18 . The pre-assembled drive assembly  26  may be adapted to generate power when the turbocharger drive  18  is rotated and direct the power to a crankshaft of an engine  46  (referring to  FIG. 4 ) to which the turbocharger  23  is attached.  
         [0021]     A turbine housing  40  is assembled to stator housing  24  to enclose turbine wheel assembly  10 . The turbine housing  40  is adapted to direct hot expanding exhaust gases through a turbine exhaust inlet  41  to the plurality of turbine blades  13  disposed on the turbine wheel base  12  to cause the turbine wheel assembly  10  and associated turbocharger drive  18  to rotate. After passing through the turbine wheel assembly  10 , the exhaust gases are released to the atmosphere through a turbine exhaust outlet  42 .  
         [0022]     A compressor assembly  37  may be connected to the other end of the turbocharger drive  18  and be adapted to rotate with the turbocharger drive  18 . The compressor assembly  37  may include a compressor wheel base  38  and a plurality of compressor blades  39  disposed around the outer periphery of the compressor wheel base  38 . Compressor assembly  37  may also include a stub shaft (not shown) having a fastening means such as for example, threads, similar to stub shaft  20  connected to turbine wheel  11 . The stub shaft of compressor assembly  37  may be adapted to connect the compressor assembly  37  to the turbocharger drive  18 .  
         [0023]     A compressor housing  43  may be assembled to the stator housing  24  that encloses compressor assembly  37 . Compressor housing  43  is adapted to direct ambient air from a compressor air inlet  44  to the plurality of compressor blades  39  attached to the rotating compressor wheel base  38 . The plurality of compressor blades  39  may be operable to compress the air and force the compressed air out of the turbocharger  23  through a compressor air outlet  45  (referring to  FIG. 4 ).  
         [0024]     As illustrated in  FIG. 4 , the turbocharger  23  of the present disclosure may be used with an engine  46  in an engine assembly  48 . The engine  46  may be a diesel engine, a gasoline engine, a natural gas engine, or any other engine known in the art. Hot exhaust gases from the engine  46  are directed into the turbine exhaust inlet  41  where the gases drive the rotation of the turbine assembly  10  resulting in a corresponding rotation of compressor assembly  37 . The rotation of compressor assembly  37  compresses inlet air and forces the compressed air into the engine  46  through compressor air outlet  45 .  
         [0000]     Industrial Applicability  
         [0025]     As will be apparent from the foregoing description, the present disclosure provides a system and method that allows for design flexibility and low cost maintenance of a turbocharger  23 .  
         [0026]     The turbocharger  23  of the present disclosure may be assembled from both ends of the turbocharger drive  18 . The pre-assembled drive assembly  26  (having stator  28 , rotor  29 , end plate retainers  34 , bearings  30 , and turbocharger drive  18 ) is balanced and then inserted into stator housing  24 . Turbine wheel assembly  10  is connected to one end of the turbocharger drive  18  by engaging threaded portion  14  of the turbine wheel assembly  10  with threaded portion  16  of the turbocharger drive  18 . Turbine housing  40  is assembled to one side of the stator housing  24  and encloses the turbine wheel assembly  10 . Compressor assembly  37  may be connected to the other end of the turbocharger drive  18  and enclosed by compressor housing  43  assembled to the other side of the stator housing  24 .  
         [0027]     Because the turbocharger  23  can be assembled from both sides of the turbocharger drive  18 , design flexibility is expanded. Design is no longer limited to components capable of assembly from only one direction. Likewise, methods of assembly are no longer limited to only one direction of assembly.  
         [0028]     In addition to increased design flexibility, maintenance costs of the turbocharger  23  may be reduced by the ability to remove both the turbine wheel assembly  10  and the compressor assembly  37  from the turbocharger drive  18 . For example, when maintaining a turbocharger having a turbine wheel permanently secured to a turbocharger drive, replacement of a damaged turbine wheel required the entire turbocharger be taken apart. Both turbine and compressor housings had to be removed and the compressor assembly had to be disconnected from the turbocharger drive. The pre-assembled drive assembly had to be removed from the stator housing along with the turbine wheel and the turbocharger drive. The pre-assembled drive assembly had to be separated from the turbocharger drive. Finally the turbine wheel and turbocharger drive could be replaced.  
         [0029]     With the turbine wheel assembly  10  detachable from the turbocharger drive  18  as described in the present disclosure, the maintenance process is simplified. For example, when replacing a broken or damaged turbine wheel assembly  10 , the turbine housing  40  is removed and the turbine wheel assembly  10  is detached. Not only is the process simplified saving time and labor cost, but part cost is also reduced.  
         [0030]     It will be apparent to those skilled in the art that various modifications and variations can be made in the turbine wheel assembly  10  of the present disclosure without departing from the scope of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the invention being indicated by the following claims and their equivalents.