Abstract:
A transmission casing adapter ring is provided that enables a transmission having a common outer casing to be operatively connected to an engine, thus enabling different engines to be used with the common transmission outer casing simply by changing the adapter ring. The adapter ring allows a novel method of assembling a powertrain that permits assembly of the transmission with a generic (i.e., common) type of casing prior to a determination of the engine type or types to be used with the transmission. The adapter ring is aluminum, the transmission case is magnesium, and the engine is cast iron.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to an apparatus for connecting a transmission case to an engine, as well as a method of assembling transmissions. 
       BACKGROUND OF THE INVENTION 
       [0002]    Vehicle powertrains are complex assemblies including a multitude of components. One of the principal components of a vehicle powertrain is the transmission, which includes a rugged outer housing or case. Transmissions are often designed and built with the intention of being offered for use by various automotive manufacturers across different applications or vehicle models. Economies of scale and simplification of component handling during vehicle assembly dictate the use of at least some common transmission components across these various applications, and even in different types of transmissions, for example in different transmission families with disparate torque and gear ratio specifications. Engines of varying designs are likely used in the different applications, leading to a less than optimal number of different parts and their associated part numbers necessary to achieve the various combinations of transmissions and engines. 
       SUMMARY OF THE INVENTION 
       [0003]    A transmission case adapter ring is provided that enables an outer transmission housing or case to be connected to an engine, thus enabling use of a common transmission case part number with different engine styles simply by changing the adapter ring. The adapter ring has engine mounting features configured to mount to a predetermined engine mounting face on a specific type or style of engine, and also has a case-side mounting face adapted to mount to a mounting face on the transmission case. The adapter ring is separate from, and mountable to, both the transmission case and the engine. Thus, the adapter ring enables an engine to be connected with any transmission that utilizes the particular type of transmission case. 
         [0004]    The adapter rings are relatively small and easy to store, and may be pre-produced and stored until needed. The adapter rings are constructed of light weight, corrosion-resistant material such as aluminum to reduce overall vehicle weight while minimizing corrosion between the transmission case and a cast engine block. With the adapter ring, it is not necessary to produce a customized transmission case for each vehicle model. 
         [0005]    Accordingly, in one aspect of the invention, an annular adapter ring has a case-side mounting face at one end adapted to mount to a mounting face of a transmission case. The adapter ring also has an engine-side mounting face at an opposite end that is adapted to mount to a predetermined engine mounting face of a particular type of engine. Preferably the case-side mounting face and the engine-side mounting face of the adapter ring are characterized by bolt patterns identical to bolt patterns of the transmission case and of the engine, respectively. 
         [0006]    In another aspect of the invention, because the adapter ring is a separate component from the transmission casing and engine, both may be manufactured separately from the adapter ring, and the adapter ring may be selected from a suitable material independently of the material used for the transmission and engine. For example, the adapter ring may be aluminum, rather than steel, in order to reduce weight and improve fuel economy, while still providing a barrier having sufficient corrosion resistance between potentially incompatible materials, such as a magnesium transmission case and a cast iron engine block. 
         [0007]    Within the scope of the invention, a powertrain is provided that includes a transmission having an outer case. The power train also includes an engine having an engine block with an engine mounting face formed on one side, such as with a specific engine bolt pattern. The powertrain includes an annular adapter ring that has a case-side mounting face adapted to mount to the transmission case and an engine-side mounting face adapted to mount to the engine mounting face, to thereby connect the transmission with the engine. 
         [0008]    The adapter ring allows a novel method of assembling a powertrain that permits assembly of the transmission with a generic (i.e., common) type of outer case prior to a determination of the engine type or types to be used with the transmission. The method includes maintaining an inventory of transmissions of a first type, each contained within an outer transmission case of a first type. The method includes mounting an adapter ring to the outer case of one of the transmissions. The adapter ring has an engine-side mounting face configured with a predetermined engine bolt pattern adapted for connection with a first type of engine that has the predetermined engine bolt pattern. 
         [0009]    Because only the adapter ring has an engine specific feature, i.e. the engine mounting bolt pattern, the method may include mounting a second adapter ring of a second type to the transmission case on a second transmission selected from the inventory, i.e., the second transmission being of identical types as those of the first transmission. The adapter ring of the second type has an engine-side mounting face configured with a second, different, predetermined engine bolt pattern so that the second adapter ring is configured for connection with a second type of engine having the second engine bolt pattern. Thus, the same generic type of transmission case may be used in different applications, such as when different types of engines are to be used with a given type of transmission, simply by utilizing different engine-specific adapter rings. 
         [0010]    Furthermore, the entity that maintains the inventory of transmissions may or may not manufacture the adapter rings, and, in either case, may maintain an inventory of the different types of adapter rings and select the appropriate type of adapter ring for mounting to the transmissions, as described above, based on orders received for use of the transmissions with the specified type or types of engines. This permits flexibility in manufacturing output. 
         [0011]    Within the scope of the invention, particularly if it is expected that a given type of transmission will be used with two or more different types of engines, the method may include maintaining an inventory of adapter rings of the first and second types, receiving an order for the first type of transmission to be used with the first type of transmission, and, in response to the order, selecting the first type of adapter ring from the inventory for the step of mounting the first adapter ring described above. This allows the transmission to be preassembled, and only the adapter rings need be maintained in a separate, engine specific inventory. Similarly, the method may include receiving an order for the first type of transmission to be used with the second type of engine, and, in response to the order, selecting the second type of adapter ring from the inventory to be used for the step of mounting the second adapter ring described above. 
         [0012]    The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a schematic side view illustration in exploded view of a first powertrain having a transmission with an outer case and first type of engine with an adapter ring to connect the case with the engine; 
           [0014]      FIG. 2  is a schematic side view illustration in exploded view of a second powertrain having a transmission with an outer case each of the same type as the corresponding components of  FIG. 1 , and a second type of engine with another type of adapter ring to connect the transmission case with the second type of engine; 
           [0015]      FIG. 3  is a schematic perspective illustration of the adapter ring of  FIG. 1 ; 
           [0016]      FIG. 4  is a schematic perspective illustration of the adapter ring of  FIG. 2 ; and 
           [0017]      FIG. 5  is a flow chart illustrating a method of assembling a powertrain such as those of  FIGS. 1 and 2 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Referring to the drawings, wherein like reference numbers refer to like components,  FIG. 1  shows a first powertrain  10  that includes a transmission  111  of a first type, and having an outer housing, shell, or case  46 . Case  46  is constructed of a heat resistant and relatively lightweight material, preferably magnesium or a magnesium alloy, but case  46  may also be constructed from other suitable materials within the scope of the invention. Transmission  11  may be configured, for example, as a specific six-speed automatic transmission with numerical speed and torque ratios between a rotatable input member  12  and a rotatable output member  13 , as determined by internal gear tooth ratios. Alternatively, transmission  11  may be a hybrid transmission or other type of transmission. 
         [0019]    Powertrain  10  includes an engine  26 , which may be configured as an internal combustion engine, a fuel cell, or another type of engine sufficient for powering a vehicle (not shown) equipped with transmission  11 , in particular by driving input member  12  of transmission  11  via an engine output member  28 . Engine  26  is a first type of engine having certain characteristic design parameters, such as displacement volume, number and orientation of cylinders, etc., and/or other design parameters depending on the type or style of engine  26 . 
         [0020]    It is desirable to be able to utilize transmission  11  with many different engine applications and associated bolt patterns while maintaining as many generic or common components, such as a singular transmission case  46 , throughout the various applications. Accordingly, powertrain  10  includes an adapter ring  32  adapted to bolt or otherwise connect transmission case  46  with a specific first type of engine  26 . This connection is achieved more specifically between case  46  and an engine block portion  54  of engine  26 , preferably a suitable grade of cast iron. Adapter ring  32  is preferably formed or cast from a high-strength, lightweight grade of aluminum to improve corrosion resistance and reduce the weight of transmission  11 . 
         [0021]    Adapter ring  32  is a first type of adapter ring having a case-side mounting face  34 , i.e. an axial surface facing transmission case  46 , and an engine-side mounting face  36  at an opposing axial surface. Case-side mounting face  34  includes features suitable for adapting the adapter ring  32  for connection to transmission case  46 , such as adapter-to-case bolt openings  38 . Case-side mounting face  34  and adapter-to-case bolt openings  38  correspond to mate up with or fit to a transmission case mounting face  40  on an outer surface of transmission case  46 , and case bolt openings  42  formed, bored, or otherwise provided in transmission case  46 . Adapter-to-case bolt openings  38  and case bolt openings  42  align, and case-side mounting face  34  fits with case mounting face  40  in this manner. Adapter ring  32  is then bolted and doweled (or piloted) to case  46 . 
         [0022]    As shown in  FIGS. 1 and 2 , respectively, an optional torque converter  20 ,  20 A may be provided having a pump portion  22 ,  22 A drivingly connected with a transmission pump (not shown) housed or contained at least partially within transmission case  46 . Pump portion  22 ,  22 A is also drivingly connected with a driving component  24 ,  24 A such as a flywheel or damper assembly, which is operatively connectable to the engine output member  28 . A turbine portion  25 ,  25 A of torque converter  20 ,  20 A is fluidly driven by discharge of fluid (not shown) from pump portion  22 ,  22 A, and operatively connects to transmission input member  12  to thereby power input member  12 , as is known in the art. Therefore, case  46  is preferably configured and/or shaped to allow torque converter  20 ,  20 A to be disposed between transmission  11  and engine  26  if so desired, with adapter ring  32  adapted for use as explained herein without interference with operation of torque converter  20 ,  20 A. 
         [0023]    Engine-side mounting face  36  of adapter ring  32  includes adapter-to-engine bolt openings  50  arranged in a predetermined pattern to align with a particular engine mounting face  51  of engine  26 . Engine  26  has a predetermined engine bolt pattern, as represented by engine bolt openings  52 , that is formed, bored, or otherwise provided in engine block  54  of engine  26 . 
         [0024]    Because adapter ring  32  is the only component of powertrain  10  having engine-specific features, i.e., features specially adapted to connect to a particular mating feature of engine  26 , such as an engine bolt pattern represented by engine bolt openings  52 , identical types of the remaining components of powertrain  10  may be used without modification in powertrains having a different type of engine, and only a different type of adapter ring need be used. This is demonstrated by powertrain  100  of  FIG. 2 , in which a second transmission of the same type as and identical to transmission  11  of  FIG. 1 , is implemented. 
         [0025]    Referring to  FIG. 2 , an alternate powertrain  100  includes a transmission  11 A that may or may not be functionally identical to transmission  11  of  FIG. 1 , but which is enclosed within an identical case  46  as used with transmission  11  of  FIG. 1  as described above. Powertrain  100  includes an engine  126  of a second type which is not identical in configuration to engine  26  of  FIG. 1 , and specifically having an engine mounting face  151  with a second engine bolt pattern in engine block  154  as represented by engine bolt openings  152 . Engine bolt openings  152  differ in number and/or spacing from engine bolt openings  52  of the first type of engine  26  shown in  FIG. 1  and described above. 
         [0026]    Because a second adapter ring  132  of a second type is used that is different than adapter ring  32  shown in  FIG. 1 , and that specifically has an engine-side mounting face  136  with mounting features, such as adapter-to-engine bolt openings  150 , arranged in a predetermined pattern to align with engine mounting face  151  having the second engine bolt pattern, as represented by engine bolt openings  152 . The case-side mounting face  34 A of second adapter ring  132  is the same as the case-side mounting face  34  of the first adapter ring  32 , as it has identically-spaced mounting features represented by adapter-to-case bolt openings  38 A. Adapter-to-case bolt openings  38 A are identical to adapter-to-case bolt openings  38  of  FIG. 1 . Therefore, second adapter ring  132  may be mounted to case mounting face  40 A and to case bolt holes  42 A of case  46 , which are respectively identical to the engine-side mounting face  40  and transmission case bolt openings  42  of transmission case  46  shown in  FIG. 1 . 
         [0027]    Referring to  FIG. 3 , adapter ring  32  of  FIG. 1  is shown in perspective side view having engine-side mounting face  36  with adapter-to-engine bolt openings  50  spaced from one another to establish a first engine bolt pattern corresponding with the engine bolt pattern of engine  26  of  FIG. 1 , as represented by engine bolt openings  52  in  FIG. 1 . Case-side mounting face  34  is at the opposite axial surface of adapter ring  32 , with adapter-to-case bolt openings  38  for connection to transmission case  46  of  FIG. 1  in the manner described above. 
         [0028]    Referring to  FIG. 4 , adapter ring  132  of  FIG. 2  is shown in perspective side view, having engine-side mounting face  136  with adapter-to-engine bolt openings  150  spaced from one another to establish the second engine bolt pattern. This second engine bolt pattern corresponds with an engine bolt pattern of engine  126  of  FIG. 2 , as represented by engine bolt openings  152 . Case-side mounting face  34 A is at the opposite axial surface of adapter ring  132 , with adapter-to-transmission case openings  138  for connection to case  46  of  FIG. 2 . 
         [0029]    Referring to  FIG. 5 , a method of assembling powertrains  200  is illustrated in a flow diagram. The steps of the method  200  will be described with reference to powertrains  10 ,  100  of  FIGS. 1 and 2  and the adapter rings  32 ,  132  of  FIGS. 1-4 , respectively. Method  200  of  FIG. 5  is a preferred embodiment, shows optional steps, and is not intended to be limited to the order of steps shown. 
         [0030]    Method  200  includes step  202 , maintaining an inventory of transmissions of a first type, such as transmissions  11  of  FIGS. 1 and 2 , each having an outer housing or case  46  of a first type. Method  200  may also include step  208 , maintaining an inventory of adapter rings of a first type (i.e. adapter ring  32  of  FIG. 1 ) and of a second type (i.e. adapter ring  132  of  FIG. 2 ), with the first type being adapted for connection to a first type of engine (i.e. engine  26  of  FIG. 1 ) and the second type being adapted for connection to a second type of engine (i.e. engine  126  of  FIG. 2 ). 
         [0031]    Under method  200 , the entity assembling transmissions  11  may receive an order under step  210  for the first type of transmission to be used with a first type of engine. Additionally or alternatively, the entity may receive an order under step  212  for the first type of transmission to be used with a second type of engine. In response to step  210 , method  200  includes step  214 , selecting the first type of adapter ring  32  from the inventory of adapter rings. 
         [0032]    After step  214 , method  200  includes step  216 , mounting the first type of adapter ring  32  to the case  46  of transmission  11  of the first type from the inventory of assembled transmissions. Similarly, in response to step  212 , method  200  includes step  218 , selecting the second type of adapter ring  132  from the inventory of adapter rings. After step  218 , method  200  includes step  220 , mounting the second type of adapter ring  132  to the first type of transmission case  46  on a transmission  11  of the first type from the inventory of transmissions. 
         [0033]    While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.