Abstract:
A powertrain includes a rotary input member such as an engine crankshaft, a torque coupling such as a hydraulic torque converter, a drive plate, such as a flex plate or spider, connecting the input member to the coupling, and an annular generator rotor having an electrical power annulus, such as an annular induction member extending around the coupling, and a mounting ring fixed to the power annulus and including means extending inward for securing the mounting ring to the coupling and to the drive plate. Several embodiments of mounting rings and assemblies are disclosed which improve methods for assembly of the powertrain.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates to a powertrain including an electric motor generator and to the manner of mounting the generator rotor.  
         BACKGROUND OF THE INVENTION  
         [0002]    U.S. Pat. No. 5,103,127 Peter, assigned to the assignee of the present invention, describes a torque converter mounted starter/generator for a motor vehicle in which the rotor of the starter/generator machine is formed on the outer circumference of an input shell of a vehicle torque converter. The arrangement provides a compact assembly but substantially increases the complexity of the combined torque converter shell and generator rotor.  
           [0003]    U.S. Pat. No. 6,208,036 Evans et al., commonly assigned, describes a vehicle powertrain with integrated motor generator wherein the generator rotor and the vehicle torque converter shell are independently connected with an engine crankshaft with the generator rotor essentially surrounding the torque converter. This arrangement substantially reduces manufacturing complexity although the difficulty of assembling the transmission and converter assembly to the engine is somewhat increased.  
           [0004]    An improved arrangement providing both manufacturing simplicity and relative ease of assembly is accordingly desired.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention provides an improved powertrain including a rotary input member such as an engine crankshaft, a torque coupling such as a hydraulic torque converter, a drive plate such as an automotive flex plate or connecting spider, and an annular generator rotor at least partially surrounding the torque coupling and connected with the coupling and the drive plate by a mounting ring forming a part of the rotor. The generator rotor includes an electrical power annulus, such as an annular induction member, and the mounting ring which is fixed to the power annulus for supporting the annulus and connecting it with the coupling and the drive plate.  
           [0006]    In a preferred embodiment, the generator rotor is of the induction motor or generator type, although other forms of generator rotors could be utilized with the invention. The mounting ring, which forms a part of the generator rotor and supports the electrical power annulus, preferably includes two integral portions, namely an annular support and an annular connector. The annular support is a cylindrical portion on which the power annulus is mounted in any suitable manner, such as by a shrink fit. The annular connector may be formed as an inwardly directed flange which includes a plurality of openings for connection of the mounting ring with the converter and with the mounting plate.  
           [0007]    Three examples of mounting ring configurations are disclosed including an angle ring, a T-ring and a C-ring, all referring to cross-sectional configurations of the various ring embodiments. In the angle ring, the annular connector or flange extends more or less radially inward from one end of the annular support or cylindrical portion. In the T-ring, the flange extends inward from a point between the ends of the cylindrical portion but closer to one end, and in the C-ring, the flange extends inward from the one end of the cylindrical portion.  
           [0008]    In the angle ring and the T-ring, the flange is generally provided with three, or more, equiangularly-spaced openings which mate with openings in the drive plate and with drive lugs on the front of the torque converter shell. A peripheral flange on the drive plate may be used to assist in aligning the components during assembly. The drive plate is connected with both the generator rotor and the torque converter by bolts inserted through the three spaced openings in the flange and threaded into recesses in the torque converter lugs.  
           [0009]    In the case of the C-ring, the flange is provided with two groups of three, or more, equiangularly-spaced openings alternating with one another around the ring. A first group has threaded nuts tack welded to the interior of the flange and bolts are inserted therein from the front or input member side of the drive plate to connect the rotor with the drive plate. A re-entrant rim on the interior edge of the flange guides on the torque converter lugs and assists in aligning the torque converter shell with the rotor during assembly of these components.  
           [0010]    The mounting ring is connected to the converter lugs through the second alternate group of three, or more, openings in the mounting ring flange through which additional bolts are inserted from the input member or crankshaft side of the mounting plate through the mounting ring openings into threaded openings in the converter lugs. The arrangement simplifies connection of the generator rotor to the torque converter when the transmission is assembled to the engine.  
           [0011]    These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a side view partially in cross section showing a portion of a powertrain including an electrical generator rotor partially surrounding a torque converter at the connection between an engine crankshaft and a connected transmission;  
         [0013]    [0013]FIG. 2 is a cross-sectional view of a portion of the connection between the crankshaft, the torque converter and the rotor of the powertrain of FIG. 1;  
         [0014]    [0014]FIG. 3 is a cross-sectional view of an alternative angle ring;  
         [0015]    [0015]FIG. 4 is a rear view of a C-ring formed according to the invention; and  
         [0016]    [0016]FIG. 5 is a cross-sectional view of the connection between the crankshaft and the rotor through the C-ring of FIG. 4. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    Referring first to FIG. 1 of the drawings in detail, numeral  10  generally indicates an engine transmission assembly including an engine  12  having a crankshaft  14  forming an engine output shaft and a transmission  16  having an input shaft  18  connected by a powertrain  20  according to the invention.  
         [0018]    Powertrain  20  includes a housing  22  which is mounted between the engine and the transmission and is assembled first to the transmission and subsequently bolted to the engine upon assembly of the transmission to the engine. The housing  22  internally mounts a stator  24  which forms a part of a motor generator  26  that forms a portion of the powertrain  20 .  
         [0019]    Within the housing  22 , the powertrain further includes a drive plate  28  bolted to the end of the crankshaft  14  and connected by bolts  30  to annularly spaced drive lugs  32  welded to the input shell  34  of a conventional vehicle torque converter  36 . The input shell  34  has a central protrusion that extends into a guide opening  40  at the end of the crankshaft  14  for supporting and maintaining alignment of the torque converter with the engine crankshaft. The torque converter  36  acts as a coupling between the crankshaft  14  with attached drive plate  28  and the input shaft  18  of the transmission.  
         [0020]    In accordance with the invention, the motor generator  26  also includes an annular rotor  42  which, in the illustrated embodiment, includes an electrical power annulus  44  of the induction motor type, although other forms of generator rotors could be utilized in accordance with the invention. Rotor  42  further includes a mounting ring  46 , shown also in FIG. 2 with other related portions of the powertrain.  
         [0021]    As shown in FIG. 2, mounting ring  46  includes a generally cylindrical annular support  48  connected with a flange  50  which defines an annular connector. The power annulus  44  is preferably mounted on the cylindrical support by an interference fit so that the mounting ring  46  and the power annulus  44  are joined to form the annular rotor  42 .  
         [0022]    In the illustrated embodiment, the torque converter input shell  34  is conventionally provided with three drive lugs  32 , each having a threaded bore  52  opening through a surface engaging the flange  50  of the mounting ring  46 . Flange  50  also includes three equiangularly-spaced openings  54  which are aligned with the threaded bores  52  and with three equiangularly-spaced openings  56  formed near the outer periphery of the drive plate  28 . Bolts  30  are installed from the input member or crankshaft side of the drive plate  28  and extend through the openings  56  and  54  of the drive plate and flange  50  to engage the threaded bores  52  of the drive lugs  32 . Thus, in this embodiment, bolts  30  connect the drive plate with both the annular rotor  42  and the input shell  34  of the torque converter.  
         [0023]    The embodiment of FIGS. 1 and 2 illustrates a first embodiment of mounting ring  46  referred to as a T-ring, since the connection of the flange  50  with the annular support  48  is spaced inwardly from the forward end of the cylindrical support  48  so as to form a T-shape in cross section. FIG. 3 illustrates an alternative embodiment of mounting ring  58 . This ring may be referred to as an angle ring because the connection of its annular connecter or flange  60  with its annular support or cylindrical portion  62  comes at adjoining ends of both elements so as to form in cross section an angle configuration. Three equiangularly-located openings  64  are provided in the flange  60  so that the mounting ring  58  could be substituted for mounting ring  46  in the embodiment of FIGS. 1 and 2 and the resulting rotor would be formed by mounting the power annulus  44  with an interference fit on the cylindrical annular support  62  of the mounting ring  58 .  
         [0024]    Referring to FIGS. 4 and 5, a third alternative embodiment of mounting ring  68  is illustrated. FIG. 4 shows a rear view of the mounting ring  68  itself while FIG. 5 shows mounting ring  68  at a section indicated by the lines  5 - 5  of FIG. 4 and assembled with other elements of the drive train. These include the crankshaft  14  and an electrical power annulus  44  which is joined with mounting ring  68  to form an annular generator rotor  70 . Mounting ring  68  is referred to as a C-ring in view of its cross-sectional configuration, which includes an annular support or cylinder  72 , an annular connector or flange  74  extending inwardly at a right angle from the cylinder  72  and a re-entrant annular guide flange  76  extending rearward from the connector flange  74 .  
         [0025]    As shown in FIG. 4, mounting ring  68  is provided with six equiangularly-spaced openings formed in two groups of three openings each, including openings  78  positioned alternately with openings  80  comprising first and second groups of openings. Openings  78  are positioned to align with threaded bores  52  of the drive lugs  32 , shown in FIG. 2 of the drawings, and with cutouts, not shown, in the drive plate  82 . The mounting ring  68  is thus connected with the torque converter  36  in the same manner as in the embodiment of FIG. 2 except that the drive plate  82  is not connected to the mounting ring  68  at these locations.  
         [0026]    Openings  80  are positioned to align with openings  84  of the drive plate  82  and also to align with threaded bores  86  of nuts  88  which are welded to the flange  74  of the mounting ring. Bolts  90  are installed through openings  84  of the drive plate  82  and openings  80  of the flange  74  to engage the threaded bores  86  of nuts  88  so as to secure the drive plate to the flange  74  of the mounting ring or C-ring  68 .  
         [0027]    In assembly of a transmission having a drivetrain connection to an engine, the drive plate  28 ,  82  is first bolted to the end of the engine crankshaft  14 . In the embodiments of FIGS. 2 and 3, the annular rotor  42  is mounted to the torque converter  36  with the openings  54  or  64  of the mounting ring flanges  50 ,  60  aligned with the threaded bores  52  of the drive lugs  32 . The transmission and attached powertrain housing  22  and torque converter  36  are then secured to the engine and the bolts  30  are inserted through the opening  56  of the drive plate  28 ,  82  and then tightened by threading them into bores  52  of the drive lugs  32  on the torque converter input shell  34 .  
         [0028]    In order to reach the bolts  30 , the assembler must reach through an opening  92 , not shown, in either side of the lower portion of the housing  22 . The heads of bolts  30  are located on the input member or crankshaft side of the mounting plate  28  so that the assembler can reach the bolt heads to tighten them in position. Completion of the operation requires rotation of the engine crankshaft and transmission in order that each of the bolts can be tightened in consecutive order.  
         [0029]    Assembly of the embodiment of FIG. 5 differs somewhat and is more convenient. The drive plate  82  is bolted to the crankshaft  14  as before. However, the annular rotor  70  is first bolted to the torque converter  36  by inserting bolts  30  through openings  78  of the mounting ring  68  and tightening the bolts  30  into the threaded bores  52  of the drive lugs  32 . Thus, the rotor  70  is fixed in place on the converter  36  before the transmission assembly is attached to the engine. Prior to installation of the bolts  30 , the annular guide ring  76  on the C-ring or mounting ring  68  extends inside the drive lugs  32  of the torque converter and thus helps align the torque converter shell and the attached lugs with the drive plate  82 . Installation of the bolts  30  is again accomplished by reaching through the opening  92  of the rotor housing  22 .  
         [0030]    Thereafter, the transmission housing  22  is attached to the engine and the openings  80  in the mounting ring are aligned with openings  84  in the drive plate. Bolts  90  are then installed from the crankshaft side of the drive plate and tightened into threaded bores  86  of nuts  88  of the mounting ring  68  to connect the drive plate  82  with the rotor  70  and the torque converter  36 . The assembly method substantially simplifies the alignment and connection of the crankshaft to the rotor and converter and reduces the time required for installing the transmission at an assembly station.  
         [0031]    While the invention has been described by reference to certain preferred embodiments, it should be understood that numerous changes could be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the disclosed embodiments, but that it have the full scope permitted by the language of the following claims.