Abstract:
A modular electrical plug connector assembly for control units in a motor vehicle includes a module rack and at least first and second plug-in modules that are situated in the module rack and that each includes respective housings shaped to accommodate respective electrical plug connectors. The housings are provided with respective electrically conductive contact elements. The first and second plug-in modules are positioned relative to one each other in a predetermined manner in the module rack, and are inseparably connected to the module rack by a joining process.

Description:
BACKGROUND 
       [0001]    Various functions in motor vehicles today are regulated or controlled by control units. For example, the ignition, fuel injection times and also the electrical power windows or the electrical sunroof are controlled or regulated by such control units. In automotive engineering today, there is an observable trend toward concentrating on a few control units with which numerous functions may be controlled. This concentration on a few control units is associated with a greater number of electrical contacts with which more actuators are controlled or regulated, and also more parameters are detected by sensors. Furthermore, the number of sensors installed is increasing steadily and these in turn require additional electrical contacts on the control units. Control units manufactured in the 1990s had far fewer than 100 contacts, but today it is standard for a control unit to have slightly less than 200 contacts. Efforts are presently underway to furnish control units with approximately 300 contacts. 
         [0002]    Already today multiple contacts are combined to form one plug-in module having a plug housing, so that one control unit includes multiple plug-in modules. Accordingly, multiple electrical connectors which are compatible with the plug-in modules or the plug housings and are connected to a wiring harness are also required for detecting the parameters supplied by the sensors and/or for triggering the actuators. 
         [0003]    The plug-in modules which are integrated into the control unit and connect the control unit to the sensors and actuators are designed in a plug connector assembly in which the plug connector assembly, which includes the plug-in modules, is manufactured in one piece, monolithically, so to speak, by the plastic injection molding method. 
         [0004]    The electrically conductive contacts connecting the printed circuits present in the control unit to the plug connectors of the wiring harnesses are designed as pin contacts made of metal. To manufacture the finished plug connector assembly, the pin contacts are inserted into the injection mold and are sheathed with plastic during the injection molding process. The pin contact protrudes approximately 8 mm out of the plastic surrounding it in the direction of the plug connector. The opposite side of the pin contact is usually bent at an angle for reasons of space and is contacted directly to the printed circuit. Each plug connector assembly is therefore manufactured in accordance with the layout of the printed circuits encompassed by the control units. 
         [0005]    On the part of automobile manufacturers, there are strict requirements on the plug connector assembly to be met by the control unit manufacturers. The individual contacts which extend in the direction of the plug connector and are combined to form a plug-in module must provide a position tolerance of 0.4 mm at their contact tips. On the other side, there is an effort on the part of the control unit manufacturers who want to ensure that the contact tips of the contact elements facing the printed circuits are precisely positioned, so that there is no problem with the tips finding the receptacles provided for them on the printed circuits. 
         [0006]    Unforeseeable warpage may occur with the plug connector assembly because of the large amount of metal due to the electrical contacts and the irregular distribution within the plug connector assembly as well as the associated possibility of differences in cooling of individual areas inside the plug connector assembly. To be able to meet the tolerances as stipulated above and nevertheless be able to manufacture the plug connector assemblies in a fully automated manner, extensive reworking on an injection molding tool is required after it has been manufactured, thus causing substantial costs. 
       SUMMARY 
       [0007]    There may thus be a need for manufacturing such plug connector assemblies less expensively and with greater flexibility in making changes in plug-in modules. 
         [0008]    According to an example embodiment of the present invention, a modular electrical plug connector assembly for control units in a motor vehicle includes a module rack and at least one first and second plug-in module, the first and second plug-in modules being situated side by side and/or in series in the module rack. The first plug-in module includes a first plug housing that is shaped to accommodate a first electrical plug connector. The second plug-in module includes a second plug housing that is shaped to accommodate a second electrical plug connector. The first plug housing includes an electrically conductive first contact element, and the second plug housing includes an electrically conductive second contact element. According to an example embodiment, the modular electrical plug connector assembly is structured for the first plug-in module and the second plug-in module to be positioned in a predetermined position relative to one another in the module rack. In addition, according to an example embodiment, the first and second plug-in modules are each inseparably connected to the module rack by a joining process. 
         [0009]    The first and second plug connectors are designed to be complementary to the first and second plug housings and both are connected to a cable, whereby the plug connector includes an electrically conductive contact. The shape of one area of the contact element, provided for contacting with the contact of the plug connector, is complementary to that of the contact of the plug connector. Thus, an electrically conductive connection between the contacts and the contact elements is established by plugging the plug connector into the corresponding plug-in modules. The area of the contact element connected to the plug-in module can be designed as a male contact or as a female contact. It is also possible to include both male and female contacts in one plug-in module. Both the module rack and the plug-in modules are usually made of nonconductive plastic. 
         [0010]    According to an example embodiment, the contact elements are introduced into the corresponding plug housing of the plug-in module during the plug housing manufacturing process. For example, according to an example embodiment, the contact elements are inserted into a plastic injection mold and are inseparably connected to the plug housing during the injection molding process. Alternatively, according to another example embodiment, the contact elements are introduced into the corresponding plug housing of the plug-in module and inseparably connected to it after the plug housing has already been manufactured, for example, by shooting the contact elements into the finished plug housing. After the first plug-in module and the second plug-in module or the first and second contact elements have been positioned in relation to one another, the plug-in modules are connected inseparably to the module rack by a joining process, for example by welding or gluing. The individual plug-in modules need not necessarily be situated in one plane; they may also be situated at a predetermined angle to one another. 
         [0011]    In another example embodiment of the present invention, the module rack of the modular electrical plug connector assembly is delimited by a front side and a rear side opposite the front side, the module rack including a first passage for the first plug-in module, extending between the front side and the rear side in the direction from the front side to the rear side and a second passage for the second plug-in module, extending between the front side and the rear side in the direction from the front side to the rear side. The first passage is designed in such a way that the first plug-in module which is insertable into the first passage is displaceable across a first plug-in direction and is rotatable about a first axis extending in parallel to the first plug-in direction. The second passage is designed in such a way that the second plug-in module which is insertable into the second passage is displaceable across a second plug-in direction and is rotatable about a second axis extending in parallel to the second plug-in direction. 
         [0012]    The plug-in module may be inserted into the module rack from the front side to the rear side of the module rack or from the rear side to the front side of the module rack. The heights of the respective plug-in modules, beyond the front side and beyond the rear side, can be respectively set as needed. The contact elements of the second plug-in module can be positioned accurately in relation to the contact elements of the first plug-in module due to the two or three translational degrees of freedom and the one rotational degree of freedom. 
         [0013]    In another example embodiment of the present invention, the first plug housing of the modular electrical plug connector assembly includes first protrusions, these first protrusions being designed in such a way that the first plug-in module cannot be pushed through the first passage. In addition, the second plug housing includes second protrusions, these second protrusions being designed in such a way that the second plug-in module cannot be pushed through the second passage. 
         [0014]    The plug-in modules may thus be inserted so far into their corresponding passages that the protrusions belonging to the corresponding housing are in contact with the front side or the rear side of the module rack. The front side or rear side of the module rack in combination with the protrusions thus determine the plane in which the individual plug-in modules are positioned. 
         [0015]    In another example embodiment of the present invention, the first protrusions are connected to form a first flange, the first flange being designed in such a way that the first passage is covered by the first flange. The second protrusions are connected to form a second flange, the second flange being designed in such a way that the second passage is covered by the second flange. 
         [0016]    This ensures that, regardless of the position of the plug-in module, the flange will reliably cover the corresponding passage. Thus the flange can at the same time also function as the adhesive surface for connecting the plug-in module to the module rack with the aid of a suitable adhesive. The flange can also be inseparably connected to the module rack at the periphery by welding. The adhesive connection as well as the welded connection ensures that the plug-in module is connected to the module rack in a dustproof, splash water-protected and possibly also waterproof and vibration-proof manner. 
         [0017]    In another example embodiment of the present invention, a seal is inserted between the first and/or second flange and the module rack. 
         [0018]    In another example embodiment of the present invention, the first plug-in module includes first locking elements which are situated on the first plug housing and are inseparably connected to the first plug housing for locking the first plug connector. The second plug-in module includes second locking elements which are situated on the second plug housing and are inseparably connected to the second plug housing for locking the second plug connector. 
         [0019]    The plug connectors are locked in this position to the corresponding plug housing with the aid of the locking elements after attachment to the plug-in module. The locking here is designed to be unlockable. The locking ensures that the plug connector may be connected to the plug-in module in a vibration-proof manner. In the case of plug connectors including a small number of contacts in particular, it is possible to omit locking if the holding forces of the contact elements of the plug-in module, which are designed to be complementary to one another, and the contacts of the plug connector are strong enough so that the plug connector is not able to be detached from the plug-in module due to vibrations. 
         [0020]    In another example embodiment of the present invention, the first contact element and the second contact element each includes a respective first subelement. The first subelement of the first contact element extends beyond the first plug housing. The first subelement of the second contact element extends beyond the second plug housing. The first subelement of the first contact element and the first subelement of the second contact element are positioned in relation to one another. 
         [0021]    The first subelement can also extend in the plug-in direction of the corresponding plug-in module into the module rack as well as against the plug-in direction. The first subelement can also extend across the plug-in direction. The first subelement of the first contact element and the first subelement of the second contact element also need not necessarily extend in the same direction. 
         [0022]    The contact elements situated inside the plug-in module are generally positioned accurately in relation to one another due to the manufacturing process of the individual plug-in module. The first subelements will generally extend against the plug-in direction of the plug-in modules, the first subelements being configured to be connected in an electrically conductive manner to the printed circuit of the control unit. There is also a positioning of the individual plug-in modules in relation to one another through a positioning based on the first subelements. Through the accurate positioning of the first subelements of all plug-in modules in relation to one another, it is possible for an electrically conductive connection of the contact elements to the at least one printed circuit of the control unit to be established with no problem even when there is fully automated manufacturing. The accurate positioning may be created, for example, in that the areas of all subelements of the individual plug-in modules, which are accommodated by the at least one printed circuit of the control unit, are provided with a position tolerance of 0.4 mm in relation to one another. These areas may be accommodated, for example, through openings, such as, for example, boreholes in the at least one printed circuit, these areas being connected to the printed circuit in an electrically conductive manner, for example, by soldering after being inserted into the openings. 
         [0023]    In another example embodiment of the present invention, the first contact element of the modular electrical plug connection and the second contact element each includes one respective second subelement, the second subelements being situated at an angle to the first subelements, the respective first and second subelements being connected to one another in an electrically conductive manner. 
         [0024]    The second subelements are generally connected directly to the printed circuits. The connection may be a soldered connection. The second subelements may also be pressed into the printed circuit. There is also the possibility of connecting the second subelements to plug connectors situated on the printed circuits. Since, for reasons of space, the plug-in modules are generally situated in such a way that the plug-in direction is in parallel to the direction of extension of the circuit board assembled with electrical components, the second subelements generally form a 90° angle to the first subelements, but they may also form any other angle. Depending on the design of the contact points of the printed circuits, the first and/or second subelements may also be designed to be of different lengths within a plug-in module. 
         [0025]    In another example embodiment of the present invention, at least one contact element from the group of the first contact element and the second contact element is formed as an electrically conductive pin. 
         [0026]    Electrically conductive contacts in pin form may be manufactured in a particularly inexpensive manner. The contacts may be manufactured in one piece. Such pins may include a circular, square or rectangular cross section, for example. The cross-sectional area may be determined on the basis of the electrical currents to be transmitted. The cross-sectional areas for triggering actuators, for example, of the ignition, are generally designed to be larger than the cross-sectional areas for the test of sensors. 
         [0027]    In another example embodiment of the present invention, the first plug-in module is different from the second plug-in module. For example, according to an example embodiment, the number of contact elements within the first plug-in module is different than the number of contact elements of the second plug-in module. According to an example embodiment, the plug housings of the particular plug-in modules are also designed differently. 
         [0028]    In another example embodiment of the present invention, a control unit for a motor vehicle is equipped with a modular electrical plug connector assembly. 
         [0029]    Some advantages of the present invention include the following. The modular configuration of the electrical plug connector assembly with the aid of a module rack and plug-in modules provides the possibility of an inexpensive and space-saving integration of the plug-in modules. The shape of the plug-in modules can be designed individually. In addition, the plug-in modules can be situated individually. The warpage and shrinkage problems mentioned at the outset, which are the result of using plastic with regard to shape and load tolerances, have largely no effect, thereby reducing or completely eliminating any tool correction costs with regard to the plug-in module position tolerances. A layout of the contact elements which ensure transmission of signals from the interior of the control unit or from the printed circuits to the plug connectors and the cables connected to them on the outside offers a new freedom of design. In addition, the injection molding tools may have a simpler design and may thus be less expensive. Due to the fact that the plug-in modules are manufactured individually, they can be manufactured with a higher precision and allow the plug forces for the plug connectors to remain within narrower limits. In addition, the modular configuration permits a greater freedom in the design of plug connectors connected to a cable. 
         [0030]    Example embodiments of the present invention are described herein in conjunction with a modular electrical plug connector assembly including a module rack and plug-in modules as well as with a control unit. It will be clear to those skilled in the art that the individual features described herein can be combined in various ways to arrive at different embodiments of the present invention. 
         [0031]    Specific example embodiments of the present invention are described below with reference to the accompanying figures. The figures are only schematic and are not drawn to scale. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1  shows a modular electrical plug connector assembly including a module rack and plug-in modules in a perspective view, according to an example embodiment of the present invention. 
           [0033]      FIG. 2  shows a cross section of the module rack including two plug-in modules, according to an example embodiment of the present invention. 
           [0034]      FIG. 3  shows a cross section of the module rack including one plug-in module and a seal, according to an example embodiment of the present invention. 
           [0035]      FIG. 4  shows a rear side of the module rack assembled with plug-in modules in a top view, according to an example embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]      FIG. 1  shows a perspective view of a modular electrical plug connector assembly  2  including a module rack  4 , a first plug-in module  6 , a second plug-in module  8 , and a third plug-in module  10 . First plug-in module  6 , second plug-in module  8 , and third plug-in module  10  are situated either side by side or in series. First plug-in module  6  includes a first plug housing  12 , second plug-in module  8  includes a second plug housing  14 , and third plug-in module  10  includes a third plug housing  16 . All plug housings  12 ,  14 ,  16  are shaped to accommodate one electrical plug connector (not shown here) in a plug-in direction S marked with an arrow. In addition, a first contact element  18  is situated in first plug-in module  6 , a second contact element  20  is situated in second plug-in module  8 , and a third contact element  22  is situated in third plug-in module  10 . Contact elements  18 ,  20 , and  22  are designed to be electrically conductive. All contact elements  18 ,  20 , and  22  extend in plug-in direction S beyond corresponding plug housing  12 ,  14 , and  16 . Plug-in modules  6 ,  8 , and  10  are situated in module rack  4 , in such a way that corresponding plug housings  12 ,  14 , and  16  extend from a front side  24  of module rack  4  against plug-in direction S. A rear side  26  opposite front side  24  of module rack  4  faces an interior of a control unit (not shown here). All contact elements  18 ,  20 , and  22  are designed as one-piece pin contacts in the example embodiment described here. The portion beyond plug housing  12 ,  14 , and  16  with respect to plug-in direction S is divided into a first subelement  50  and a second subelement  52 . First subelement  50  extends in plug-in direction S. Second subelement  52  is at an angle to the first subelement, first subelement  50  and second subelement  52  forming an angle α. In the illustrated example embodiment, the angle a is 90°. First subelement  50  and second subelement  52  may also be of different lengths within a plug-in module  6 ,  8 ,  10 . The at least one second subelement  52  is provided for being accommodated in and/or on a printed circuit (not shown here). In the present example embodiment, the at least one second subelement  52  is shaped for insertion into boreholes in a circuit board of the printed circuit and soldered there. Second subelements  52  are aligned in parallel to one another and extend all in the same direction. Second subelements  52  are positioned in relation to one another in such a way that the position tolerance at all ends provided for soldering to the circuit board is 0.4 mm. In addition, the position tolerance of second subelements  52  to rear side  26  of module rack  4  may also be 0.4 mm. 
         [0037]    First plug housing  12  delimits a first interior space  13 , second plug housing  14  delimits a second interior space  15 , and third plug housing  16  delimits a third interior space  17 . Third subelements  54  (shown in  FIG. 2  with respect to plug-in module  6 ), designed as pins, protrude approximately  8  mm into interior spaces  13 ,  15 , and  17  of plug housings  12 ,  14 , and  16 . First locking element  46  and second locking element  48  are formed on the narrow sides of plug-in modules  6 ,  8 , and  10 . Locking elements  46  and  48  lock the plug connectors inserted into plug housings  12 ,  14 , and  16  (not shown here). To remove the plug connectors from plug housings  12 ,  14 , and  16 , locking elements  46  are  48  are unlockable, the release mechanism mostly being formed on the plug connectors. Locking elements  46  and  48  prevent the plug connectors from being unlockable automatically from plug-in modules  6 ,  8 , and  10  due to vibrations, for example. Plug-in modules  6 ,  8 , and  10  are inseparably connected to module rack  4 . 
         [0038]      FIG. 2  shows a cross section through module rack  4  including first plug-in module  6  and third plug-in module  10 , according to an example embodiment of the present invention. A first passage  28 , a second passage  30  and a third passage  32  are formed in module rack  4 . First passage  28  is designed to accommodate first plug-in module  6 , second passage  30  is designed to accommodate third plug-in module  10 , and third passage  32  is designed to accommodate second plug-in module  8  (not shown here). Passages  28 ,  30 , and  32  extend between front side  24  and rear side  26  of module rack  4  in the direction from front side  24  to rear side  26 . It is clearly apparent that first plug-in module  6  is different from third plug-in module  10 . In the present example embodiment, first plug-in module  6  and third plug-in module  10  are inserted from rear side  26  of module rack  4  along a plug-in direction E to front side  24  of module rack  4 . Plug-in direction E extends in parallel to passages  28 ,  30 , and  32 . Plug-in direction E of plug-in modules  6  and  10  is against plug-in direction S of the plug connectors (not shown here). It is clearly apparent that passages  28  and  30  are larger than corresponding plug-in modules  6  and  10 . Plug-in modules  6  and  10  here may be displaced across plug-in direction E for more accurate positioning. In addition, a first axis  34  extends in parallel to plug-in direction E, about which first plug-in module  6  is rotatable at a predetermined angle. A second axis  36  also extends in parallel to plug-in direction E about which third plug-in module  10  is also rotatable at a predetermined angle. The rotatability of plug-in modules  6  and  10  is indicated by curved double arrows  56 . To prevent plug-in modules  6  and  10  from being insertable through passages  28  and  30 , respectively, first plug housing  12  includes a first peripheral flange  38  and third plug housing  16  includes a second peripheral flange  40 . According to an example embodiment, the flanges  38  and  40  are designed like disks, and in such a way that they cover passages  28  and  30 , regardless of the position within passages  28  and  30  assumed by plug-in modules  6  and  10 . 
         [0039]    Plug-in modules  6  and  10  are positioned by the fact that first subelements  50  protruding beyond plug housings  12  and  16  are set at a predetermined distance from one another. In this condition, individually manufactured plug-in modules  6  and  10  are inseparably connected to module rack  4 , which is designed in one piece with the aid of a joining process. In the example embodiment shown here, third plug-in module  10  has been welded to module rack  4 , the weld seam being represented by a welding bead  42 . The peripheral weld seams ensure that plug-in modules  6  and  10  are connected to module rack  4  in such a way that neither dust nor splashed water is able to migrate between (a) plug-in modules  6  and  10  and (b) passages  28  and  30  from front side  24  to rear side  26  and thus possibly be able to penetrate into an interior unit at rear side  26 . 
         [0040]      FIG. 3  shows a cross section through module rack  4  including first plug-in module  6 , according to an example embodiment of the present invention. In this example embodiment, a seal  44  covering first passage  28  is situated between first flange  38  and rear side  26  of module rack  4 . 
         [0041]      FIG. 4  shows rear side  26  of module rack  4  including plug-in modules  6 ,  8  and  10  in a top view. Rear side  26  faces the printed circuit (not shown here). Contact elements  18 ,  20 , and  22  of corresponding plug-in modules  6 ,  8  and  10  are shown to be of different thicknesses. This is also continued in a cross-sectional area of individual contact elements  18 ,  20  and  22 , so that a cross-sectional area of second contact element  20  is larger than a cross-sectional area of first contact element  18 , for example. Thus, second contact element  20  is able to transmit higher currents than first contact element  18 , for example to control or regulate actuators such as, for example, the ignition or the fuel injection, while, for example, parameters detected by sensors are transmitted with the aid of contact elements  18  and  22  including the smaller cross section(s). In the example embodiment shown here, all second subelements  52  end at the same height. All contact elements  18 ,  20 , and  22  of corresponding plug-in modules  6 ,  8 , and  10  are electrically conductively connected to the printed circuit. The electrical conductivity in the example shown here is ensured, for example, by a soldering process. For this purpose, the second subelements are therefore inserted into boreholes located in a circuit board of the printed circuit.