Abstract:
A system including a sensor and an electrical cable including electrical conductors, which are provided with an electrically insulating sheathing, the sensor being accommodated in a housing, the conductors of the cable are exposed from the sheathing at certain locations and the housing is fastened in an integrally bonded or form-fitting manner on the conductors of the cable at the exposed locations in the sheathing, and an electrically insulating sheathing is provided, which encloses the housing in a form-fitting manner and covers at least the cable in the area of the housing.

Description:
RELATED APPLICATION INFORMATION 
     The present application claims priority to and the benefit of German patent application no. 10 2014 223 356.9, which was filed in Germany on Nov. 17, 2014, the disclosure of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention is directed to a system for mechanically connecting and electrically contacting a sensor to an electrical cable. 
     BACKGROUND INFORMATION 
     The related art describes electronic components having a low number of poles, such as inertial sensors for safety systems, such as ABS or ESP, which are mounted manually by the vehicle manufacturer during final assembly or, alternatively, by the supplier following installation of the cable harness. Assembly usually involves a screw connection of the sensor directly onto the vehicle body or, alternatively, using a preassembly group. The electrical contacting of the sensor is accomplished following its mechanical fixation via a plug system in another work step. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to simplify the production steps mentioned above and to permit a simple integration of the sensor into the electrical cables or the cable harness. 
     The present invention relates to a system including a sensor accommodated in a housing and an electrical cable. One advantage of the present invention is that the conductors of the cable are exposed at certain locations, and the housing including the sensor is fastened on the conductors of the cable in an integrally bonded and/or form-fitting manner at these exposed locations of the cable. Furthermore, an electrically insulating sheathing is provided, which encloses the housing in a form-fitting manner and covers the cable at least in the area of the housing. 
     Due to the integration of the sensor into the cable or cable harness, which is achieved in this way, the plug contacting clamp in the sensor housing and the mating plug housing in the cable harness may be omitted in an advantageous manner. The sensor may be placed at an arbitrary point on the cable or, alternatively, it may also be positioned as the termination of the electrical cable. 
     Additional advantageous embodiments and improvements of the system according to the present invention are stated in the subclaims. 
     In one specific embodiment, the sheathing encloses the cable in the area of the housing in a form-fitting manner, so that the cable is embedded in the sheathing. 
     The integrally bonded connection of the sensor to the cable may be accomplished by soldering, for example, by reflow soldering, a soft soldering method, such as that may be used for soldering so-called SMD (surface-mounted device) components. 
     An alternative form-fitting connection or integration of the sensor with the cable involves providing the conductor of the cable with contacts, which may be with so-called crimp contacts, into which the housing or the so-called package is inserted, mechanically secured and electrically contacted. 
     In one specific embodiment, the electrical contacts of the conductors are implemented as electromagnetic shielding at these connection points, so that effective EMC protection is implementable at the same time. 
     The housing of the sensor is provided with a sheathing, which may be made of a thermomechanically adapted thermosetting material. Thus, on the one hand, a permanently durable and thermally resistant and optionally tight sheathing is established. Furthermore, a complex thermoplastic extrusion may be omitted when using the thermosetting extrusion. 
     In one specific embodiment, straps provided with openings are formed simultaneously during the manufacture of the sheathing and are used to accommodate fastening elements. The latter may be configured as expanding rivets, for example, with the aid of which the housing including the sensor and the cable is fastened on the vehicle body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the basic setup of the system according to the present invention in a first exemplary embodiment. 
         FIG. 2  shows an exploded view of the setup according to  FIG. 1 . 
         FIG. 3  shows the basic setup of the system according to the present invention in a second exemplary embodiment. 
         FIG. 4  shows an exploded view of the setup according to  FIG. 3 . 
         FIG. 5  shows a cross section through the contacts and the housing including the sensor from  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically shows a sensor  4  connected mechanically and electrically to an electrical cable  2 . Sensor  4  is embedded in a housing  18 . Housing  18  is enclosed by a sheathing  20 .  FIG. 2  shows an exploded view of  FIG. 1 . 
     Cable  2 , which is provided with an electrically insulating sheathing  6 , includes four conductors  8 ,  10 ,  12 ,  14  in the present exemplary embodiment. Cable  2  may be part of a cable harness of a vehicle, for example. Two central conductors  10  and  12  are integrally bonded, both electrically and mechanically, to housing  18  of sensor  4  by a soft soldering method, for example, the reflow soldering mentioned above. For this purpose, soldering paste  16  is applied to conductor surfaces  50 , which are open on the cable side, of the two central conductors  10 ,  12 , and then sensor  4 , which is integrated into housing  18 , is connected to the two conductors  10 ,  12 . This entire composite is in turn enclosed tightly with sheathing  20 , which is manufactured by extrusion of cable  2  and housing  18 , which may be done using a thermosetting material. Instead of the thermosetting material, other electrically insulating materials may also be used to manufacture sheathing  20 . Sheathing  20  covers at least cable  2  in the area of housing  18 , so that the space between housing  18  and the top side of cable  2  is sealed. In another specific embodiment, cable  2  including housing  18  and sensor  4  is embedded in sheathing  20 . The top side of cable  2  and the bottom side of cable  2  are then both covered by sheathing  20  in the area of housing  18 . Sheathing  20  may be configured in such a way that at least electrical contacts  51  and contacts  34 ,  36 , and optionally housing  18  including sensor  4  and contacts  34 ,  36 , are enclosed tightly. 
     Sensor  4  may additionally have an evaluation circuit, in particular an ASIC circuit, in housing  18 . Furthermore, the housing including sensor  4  may be configured as an LGA sensor, electrical contacts  51  ( FIG. 5 ) for electrical contacting of the sensor and the evaluation circuit being provided on the bottom side of housing  18 . Housing  18  including sensor  4  and the evaluation circuit may thus form a sensor chip set. 
     Soldering pastes  16  may be provided in the form of soldering paste pads. 
     During the manufacture of sheathing  20  with the aid of a corresponding injection mold, straps  22  and  24 , which are provided with corresponding openings for accommodating fastening elements  26  and  28  and are formed in one piece on sheathing  20 , are also manufactured at the same time in the exemplary embodiment shown here. During fastening of cable  2  on the vehicle body, fastening elements  26 ,  28 , which are configured as expanding rivets, engage in corresponding openings in the vehicle body. 
     In a second exemplary embodiment, which is described below on the basis of  FIGS. 3 and 4 , a sensor  4 , which is also integrated into a housing  18 , is secured to an electrical cable  32 , the two central electrical conductors  33  and  35  being provided with contacts  34 ,  36  on one end of the four-core cable  32  in this case, housing  18  of the sensor being inserted into these contacts, mechanically secured and electrically contacted. Contacts  34 ,  36  may be configured as crimp contacts. 
     Housing  18  is in turn provided with a sheathing  20 , which may be manufactured by extrusion using a thermosetting material. Instead of the thermosetting material, other electrically insulating materials may also be used to manufacture sheathing  20 . Sheathing  20  encloses cable  2  and housing  18  including sensor  4 . Sheathing  20  may also enclose the top side and the bottom side of cable  2 . Sheathing  20  in the exemplary embodiment shown here has two straps  40  and  42 , which are manufactured together with sheathing  20  during injection molding. Straps  40 ,  42  have two openings, in which fastening elements in the form of two expanding rivets  44  and  46  are again accommodated, with the aid of which the sensor and cable  32  are fastened on the vehicle body. Sensor  4  may additionally have an evaluation circuit, in particular an ASIC circuit in housing  18 . Furthermore, housing  18  including sensor  4  may be configured as an LGA sensor, whereby electrical contacts  51  ( FIG. 5 ) for electrical contacting of the sensor and the evaluation circuit are provided on the bottom side of housing  18 . Housing  18  including sensor  4  and the evaluation circuit may thus form a sensor chip set. 
       FIG. 5  shows a schematic cross section through housing  18  including sensor  4 , whereby an evaluation circuit, in particular an ASIC circuit, may be provided in housing  18 , depending on the specific embodiment selected. Housing  18  is mechanically secured by contacts  34 ,  36 , and sensor  4  is electrically connected to contacts  34 ,  36  by electrical contacts  51 , which are provided on the bottom side of housing  18 . Furthermore, after assembly of housing  18 , sheathing  20  may be extruded, using a thermosetting material. In the process, contacts  34 ,  36 , and, optionally, housing  18  are enclosed tightly. Instead of a thermosetting material, other electrically insulating materials may also be used to manufacture sheathing  20 . 
     Sheathing  20  may be formed in such a way that at least electrical contacts  51  and contacts  34 ,  36 , and optionally housing  18  including sensor  4  and contacts  34 ,  36 ,  51  are enclosed tightly. 
     In the specific embodiment illustrated here, contacts  34 ,  36  each have a bottom wall  54 , a side wall  52  and a top wall  53 . 
     Side walls  52  are formed at a right angle to bottom wall  54  of conductors  33 ,  35 . Top walls  53  are situated in parallel to bottom wall  54  of conductors  33 ,  35  and facing one another. However, there remains a distance between the two top walls  53  situated in one plane. Contacts  34 ,  36  including bottom walls, side walls  52  and top walls  53 , form a receiving space for receiving housing  18 . With the aid of the receiving space, housing  18  may be held mechanically before being extruded with sheathing  20  and electrical contacts  51  may be electrically contacted to bottom walls  54 . Contacts  51  and contacts  34 ,  36  in particular are electrically insulated and may be sealed against moisture with the aid of sheathing  20 . Contacts  34 ,  36  of the conductors may be configured as crimp contacts  34 ,  36 , the crimp contacts being mechanically secured on and electrically contacted on the cable or corresponding conductors  33 ,  35  via a corresponding crimp assembly. 
     The receiving space also provides EMC protection since housing  18  and thus also sensor  4  and also optionally an evaluation circuit (ASIC), which is provided, are shielded over large areas by bottom walls  54 , side walls  52  and top walls  53 . 
     The sensor may be configured, for example, as a motion sensor, an acceleration sensor or an inertial sensor for measuring an acceleration and a rotation rate, e.g., for safety systems, such as ABS/ESP or airbag systems.