Abstract:
A method for establishing electrical communication between a control module and a motor/generator in a hybrid electromechanical transmission includes providing a preassembled terminal subassembly including a first plurality of wire terminals sufficiently interconnected for selective, substantially unitary movement with respect to a transmission housing, aligning the preassembled terminal subassembly with a second plurality of wire terminals affixed with respect to at least one electric motor/generator, and establishing electrical communication between each of said first plurality of wire terminals and a respective one of said second plurality of terminals.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/555,270, filed Mar. 22, 2004 and U.S. Provisional Application No. 60/555,141, filed Mar. 22, 2004, each of which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This invention relates to wiring terminal subassemblies for the establishment of electrical communication between a control module and motor/generators in a hybrid electromechanical transmission. 
     BACKGROUND OF THE INVENTION 
     Electrically variable transmissions (EVTs) typically include two electric motor generators each having a respective rotor. EVTs also include a gearing arrangement typically having a plurality of planetary gearsets with respective sun, ring, and planet carrier members. Selectively engageable torque transmitting devices, such as clutches and brakes, selectively interconnect members of the planetary gearsets to each other and to the transmission housing to provide selective power paths from a transmission input shaft to a transmission output shaft. 
     The rotors are connected to a respective planetary gearset member for unitary rotation therewith so that the transmission is capable of establishing a continuously variable speed ratio between the input and output shafts wherein the speed ratio is proportional to the speed of one of the rotors. An EVT typically includes an energy storage device such as a battery, and an electronic controller connected to both the battery and the motor/generators to control the flow of electrical energy to and from the motor/generators. 
     Therefore, in assembling EVTs, electrical connections must be established between the electronic controller and each of the motor/generators. However, establishing the electrical connections between the motor/generators and the electronic controller may be difficult due to the complex nature of an EVT and the placement of the motor/generators inside the transmission housing. Moreover, a large number of parts involved in prior art EVT electrical connections results in the assembly of the EVT being labor-intensive. 
     SUMMARY OF THE INVENTION 
     A method is provided for establishing an electrical connection between a control unit and at least one motor/generator in a hybrid electro-mechanical transmission. The method includes providing a preassembled terminal subassembly having a first plurality of wire terminals sufficiently interconnected with one another to enable selective, substantially unitary movement with respect to a transmission housing. The method also includes aligning the preassembled terminal subassembly with a second plurality of wire terminals affixed with respect to at least one electric motor/generator, and establishing electrical communication between each of said first plurality of wire terminals and respective ones of said second plurality of terminals. 
     The method of the invention provides a rapid and efficient establishment of an electrical connection between a motor/generator and a control unit by eliminating loose pieces that must be hand assembled piecemeal during final transmission assembly. 
     In an exemplary embodiment, a single preassembled terminal subassembly is used to interconnect a control unit and energy storage device with two electric motor/generators, thereby establishing electrical communication between two motor/generators, the control unit, and the energy storage device. The method provided may thus reduce the number of steps involved in transmission assembly and reduce the quantity of parts involved in the assembly process. 
     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 
         FIG. 1  is a schematic fragmentary cross-sectional view of a hybrid electromechanical transmission in accordance with the invention; 
         FIG. 2  is a schematic fragmentary cross-sectional view of a frontward portion of the transmission of  FIG. 1 ; 
         FIG. 3  is a schematic fragmentary cross-sectional view of a rearward portion of the transmission of  FIG. 1 ; 
         FIG. 4  is a schematic perspective view of a housing and attached cover for a motor module with an electrical connector assembly used in the transmission of  FIG. 1 ; 
         FIG. 5  is a schematic, perspective, partially exploded view of the electrical connector assembly and internal motor wiring of  FIG. 4 ; 
         FIG. 6  is a schematic, perspective, partially exploded view of a wiring assembly connecting the electrical connector assemblies of the motor modules of  FIGS. 1-3  with a control module; 
         FIG. 7  is a schematic perspective view of the wiring assembly of  FIG. 6 ; and 
         FIG. 8  is a schematic perspective view of the housing of the transmission of  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, wherein like reference numbers refer to like components,  FIG. 1  shows the upper half of a transmission  10 , in cross sectional view. The lower half of the transmission (not shown) is disposed on the opposite side of center axis  12 . First and second electric motor modules  14 ,  16 , respectively, are disposed about the center axis  12  within the transmission  10 . A main shaft  20  is longitudinally disposed and rotatable about the center axis  12 . A plurality of inner sleeves, such as sleeve  22 , are concentrically disposed about the main shaft  20 , and are likewise rotatable about the center axis  12 . An input shaft  24  is disposed forward of the main shaft  20  and is operable for transferring power from an engine (not shown) to the transmission  10 . Engagement of one or more of a plurality of clutches included in the transmission  10  (first, second, third and fourth clutches,  26 ,  28 ,  30  and  32  respectively, being shown) interconnects one or more of first, second and third planetary gear sets  34 ,  36 , and  38 , respectively, to transfer power at varying ratios to an output member (not shown). As will be readily understood by those skilled in the art, each of the planetary gear sets includes a sun gear member, a planet carrier assembly member and a ring gear member. A fifth clutch, referred to as a lockout clutch  42 , is operable for locking out torsion isolator  44  from surrounding structural elements, and to provide a direct connection between the engine and transmission. 
     Each motor module  14 ,  16  includes a motor/generator  46 A,  46 B, respectively. The motor/generators  46 A,  46 B are preferably three-phase electric motors; however, other motor configurations may be employed within the scope of the claimed invention. Each motor/generator  46 A,  46 B includes a rotor  48 A,  48 B, respectively, and a stator  50 A,  50 B, respectively. Rotor  48 A is operatively connected to one of the members of one of the planetary gearsets for unitary rotation therewith, as understood by those skilled in the art. Similarly, rotor  48 B is operatively connected to one of the members of one of the planetary gearsets for unitary rotation therewith, as understood by those skilled in the art. 
     The transmission  10  also includes an electronic controller  51  and an electrical energy storage device  52  such as one or more batteries operatively connected to the controller  51 . A plurality of wires  53  interconnect the motor/generators  46 A,  46 B with the controller  51 , which regulates power flow between the motor/generators  46 A,  46 B, and between the energy storage device  52  and the motor/generators  46 A,  46 B, as understood by those skilled in the art. 
     Referring to  FIGS. 2 and 3 , the first and second motor modules  14 ,  16 , respectively, are each self-contained assemblies. Each module  14 ,  16  includes a respective module housing  54 A,  54 B that is preferably a flow-formed drum that includes a generally axially-oriented segment  56 A,  56 B and a generally radially-oriented segment  58 A,  58 B that cooperate to define a cavity  60 A,  60 B that contains the rotor and stator. A stamped module housing cover  62 A,  62 B is included in each of the modules and is connected to a respective housing  54 A,  54 B to close cavities  60 A,  60 B. The modules  14 ,  16  may be pre-assembled prior to installation in the transmission  10 . 
     Motor module  14  is substantially identical to motor module  16 . Although the motor modules have substantially identical components, they are oriented within the transmission in opposite directions along the centerline  12 . More specifically, the housing covers  62 A,  62 B face opposite directions along the transmission centerline  12 . 
     Each housing  54 A,  54 B includes external mounting tabs  72  radially spaced about the cover at which the housings  54 A,  54 B are bolted to the transmission housing  18  by bolts  73 . The tabs  72  provide easily accessible attachment and assist in aligning the motor modules  14 ,  16  during assembly to the transmission housing  18 . 
     Referring to  FIG. 4 , motor module  14  is schematically depicted, and is representative of motor module  16  of  FIGS. 1-3 . At least one of the mounting tabs  72  on cover  62 A preferably includes an alignment hole  70  to ensure proper alignment during the installation of the motor module  14  to the transmission housing. Housing  54 A defines access ports  75 A,  75 B formed at a peripheral edge thereof with lanced tabs  76 . An electrical connector assembly  78  is integrated into the motor module  14  by attachment at one of the access ports (shown here attached at access port  75 A). More specifically, electrical connector assembly  78  is partially inserted into access port  75 A for retention with respect to the module housing  54 A. 
     Referring to  FIGS. 4 and 5 , the connector assembly  78  includes an isolator  82 . Isolator  82  is a molded piece of highly electrically insulative material, preferably a polymeric material as understood by those skilled in the art. The isolator  82  defines three cavities  86  that are spaced apart from one another and separated by ridges  90 . Each cavity  86  is partially formed by a respective generally flat surface  94 . The connector assembly  78  also includes three nuts  98  that are insert molded in the isolator  82  so as to be nonrotatably affixed to the isolator  82 . Each nut  98  defines a respective threaded hole  100  that aligns with a respective hole  102  formed by the isolator  82  in each of surfaces  94 . 
     The motor module  14  includes three conductive paths which, in the embodiment depicted, are internal wires  104  operatively connected to the stator for transmission of electrical energy to or from the motor module  14 . Each wire  104  includes a terminal  106  connected thereto, each terminal  106  including a flat terminal plate  110  with a hole  114  defined therein. The terminals  106  are depicted as being separate pieces connected to the wires  104  so as to be in electrical communication therewith. However, and within the scope of the claimed invention, the terminals may be integrally formed with the wires  104 . 
     Each terminal plate  110  extends through a respective slot  118  in the isolator  82  such that each terminal plate  110  contacts a respective isolator surface  94  and each hole  114  aligns with a respective isolator hole  102  and a respective nut hole  100 . It may be desirable for the terminal plates  110  to have a snap-fit connection to the isolator  82  for positive retention of the terminal plates  110  with respect to the connector assembly  78 . Each slot  118  is preferably tapered so that a wide end of the slot receives a respective terminal plate  110 , and each slot narrows to guide and capture the plate to a constrained final position, as shown in  FIG. 4 . 
     The isolator  82  also includes a tab  120  and a stop member  124 . Tab  120  includes an inclined surface  122  to allow insertion of the isolator and tab into access port  75 A. The tab  120  is configured to prevent removal of the isolator  82  from the access port, and the stop member  124  is configured to prevent overinsertion of the isolator through the access port, through physical part interface with the housing  54 A. 
     Referring to  FIG. 6 , motor module  16  also includes an electrical connector assembly  78  inserted in an access port  75 B in module housing  54 B. The motor modules  14 ,  16  are arranged inside a cavity  126  formed in the transmission housing  18 , as shown in  FIGS. 1-3  and  8 , such that the connectors  78  of the first and second motor modules  14 ,  16  are adjacent to one another and so that terminal plates  110  face radially outward from the centerline  12 , and the holes  114  formed by plates  110  are arranged generally linearly at the same axial location in the transmission. This arrangement enables the use of a preassembled terminal subassembly  128  that interconnects the external wiring  53  from the controller to the internal wires  104  (shown in  FIG. 4 ) of each of the motor modules  14 ,  16 . 
     Terminal subassembly  128  includes a terminal box housing  136  defining a generally rectangular aperture  140 . Six circular apertures or ports  144  are formed in the housing  136  and extend from the rectangular aperture  140  to an outer surface of the housing. Each of external wires  53  from the electronic controller is routed through a respective port  144  so that wire terminals  148  at the ends of wires  53  are inside aperture  140 . Ports  144  are sealed to prevent moisture or debris from entering the housing  136  when it is attached to the transmission housing. Each terminal  148  includes a flat terminal plate  152  defining a hole  156 . 
     Referring to  FIGS. 6 and 7 , preassembled terminal subassembly  128  includes conductive rods, i.e., cylindrical sleeves  164 . Each sleeve  164  has a respective first end  168  and a respective second end  172 . Each sleeve  164  further defines a cylindrical hole  176  that extends from the first end  168  to the second end  172  of the sleeve  164 . The subassembly  128  includes two sleeve insulators  180 , which may also be referred to as “terminal shields,” and which are formed of a flexible, highly nonconductive material. Each of the insulators  180  defines three cylindrical openings  184  through which a respective sleeve  164  is inserted. The sleeve insulators  180  thus separate and prevent electrical communication between the sleeves, and preferably also provide shock-proofing to the terminal subassembly  128 . Each insulator  180  also includes a portion  186  that partially defines a loop through which one of the terminals  148  or wires  53  extends to retain the insulators  180 , along with the conductive rods and threaded fasteners, to the terminal box housing  136 . 
     Threaded fasteners, i.e., bolts  188 , are used in conjunction with the insulators  180  to connect each sleeve  164  to a respective terminal plate  152  prior to final assembly. More specifically, each of the bolts  188  extends through the hole  156  of one of the terminal plates  152  and through the respective hole  176  of one of the sleeves. Three of the sleeves  164  extend through a respective cylindrical hole  184  in one of the insulators  180 , and another three sleeves  164  extend through a respective cylindrical hole  184  in the other of the insulators  180 . The fit of the cylindrical sleeves  164  in the cylindrical holes of the isolators  180  keeps the bolts  188 , and cylindrical sleeves  164  in place in the terminal assembly  128 . The terminal box housing  136  retains the terminals, bolts, and sleeves  164  so that they are substantially linearly arranged and face the same direction for ease of assembly to connectors  78  of the motor modules  14 ,  16 . The terminal subassembly  128 , being preassembled prior to connection to connectors  78 , facilitates transmission assembly by eliminating loose parts and by forming a module that is selectively movable as a unit with respect to the transmission housing and the motor/generators. 
     As seen in  FIG. 6 , the terminal box spaces each of the terminals so that the bolts are alignable with a respective terminal on one of the connectors of modules  14 ,  16  by sufficiently positioning the terminal subassembly with respect to the modules. To establish the electrical connection between the controller and the motors, the terminal box is aligned with an aperture  190  formed in the transmission housing  18  (shown in  FIG. 8 ) with which the connectors  78  of the motor modules  14 ,  16  are aligned. The terminal box is affixed to the transmission housing via bolts  200 . A gasket is preferably employed with a cover  204  to sealingly close the aperture  190 . Each bolt  188  is torqued so as to extend through the hole  114  of a respective terminal plate  110  and extend through and engage the hole  100  of a respective nut  98  (shown in  FIG. 5 ) thereby causing the first end  168  of each sleeve  164  to contact a respective terminal plate  152  and the second end  172  of each sleeve  164  to contact a respective terminal plate  110  on one of the connectors  78  of motor modules  14 ,  16 . More specifically, three of the wires  53  are in electrical communication with the internal wires of motor module  14 , and three of the wires  53  are in electrical communication with the internal wires of motor module  16 . 
     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.