Abstract:
A sensor arrangement for a vehicle includes a sensor unit, a cable arrangement, and an elastic cap. The sensor unit has a main support, an electronics part connected to the main support, and a sensor element. The cable arrangement has at least one individual wire, and is configured to electrically contact the electronics part via at least one contact-making member. The main support is an open housing defining at least one insertion opening configured to accommodate the at least one contact-making member and an accommodation pocket configured to at least partially accommodate the electronics part. The elastic cap has a member configured to fasten the sensor unit in the vehicle, is configured to be pushed at least partially over the main support, and closes off the accommodation pocket in a sealed manner.

Description:
This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2012/050717, filed on Jan. 18, 2012, which claims the benefit of priority to Ser. No. DE 10 2011 004 447.7, filed on Feb. 21, 2011 in Germany, the disclosures of which are incorporated herein by reference in their entirety. 
     The disclosure relates to a sensor arrangement for a vehicle. 
     Currently, in the case of two-wheeled vehicles and four-wheeled vehicles sensor arrangements that are arranged in the region of the wheels and are used for example to detect the rotation rate and/or the direction of rotation are encased and/or encapsulated by a synthetic material and are mounted on the vehicle by way of metal inserts that are embodied as mounting bushings. The encapsulation of the sensor units as a protection against environmental influences is generally provided by way of injection molding a mass around a sensor core, which sensor core comprises at least one sensor element and a holding element to hold the sensor element, wherein the sensor element can be contacted in an electrical manner by way of a connecting cable to at least one connecting conductor and/or to a control device. A synthetic material is generally used as a protection against environmental influences, which synthetic material in the hardened state has a more constant effect on the temperature influences and the media influences and as a consequence continues to have an effect over the entire predetermined serviceable life of the sensor elements. This type of encapsulation of special sensor elements is used in the case of connections that are subjected to static, dynamic and/or impact loadings, for example in the case of rotation rate sensor units in the motor vehicle. 
     A method and a device for producing a sensor unit is described in the unexamined German application DE 10 2008 005 315 A1. The described sensor unit is embodied as a magnetic field sensor, in particular as a rotation rate sensor and/or as a direction of rotation sensor for detecting the wheel rotation and/or for detecting rotational movements in the drive train of a motor vehicle. The sensor unit comprises a sensor core that comprises a sensor element having evaluating electronics and a holding element for holding the sensor element, wherein the sensor element can be contacted in an electrical manner by way of a connecting cable to at least one connecting wire. The sensor core and the end of the connecting cable are encased and/or encapsulated with a synthetic material using an injection molding process, wherein the synthetic material casing often comprises polyamide and glass fibers. A fastening clip for fastening the sensor unit to the motor vehicle is injection molded onto the synthetic material casing. During this second injection molding process a metal mounting bushing is preferably injection molded into the fastening clip. The sensor unit is fastened to the motor vehicle by way of this mounting bushing. 
     Furthermore, a rotation rate sensor and/or a direction of rotation sensor for a magnetic field sensor that is embodied for a vehicle wheel is described in the unexamined German application DE 10 2006 050 177 A1, in which a synthetic material is injection molded around a magnetic field-sensitive sensor element together with its holding element. The synthetic material casing also encases in this case the end of a connecting cable and is embodied in such a manner that the injection molding mass forms a fastening clip having a mounting bushing for mounting the sensor. 
     SUMMARY 
     The sensor arrangement in accordance with the disclosure for a vehicle having the features disclosed herein has in contrast thereto the advantage that it is possible to reduce the costs for the production of the sensor arrangement since only one injection molding process is necessary for the production of the main support that is embodied as the housing and said housing is closed in a sealing manner by an elastic cap and is fastened in the vehicle without the use of screws. In this case, the elastic cap assumes the task of sealing the installation site with respect to the environment in an advantageous manner, i.e. the installation site of the sensor arrangement on a wheel and/or on a gear box and/or on an engine is sealed with respect to the environment by way of the elastic cap. Furthermore, the elastic cap comprises means for fastening the sensor unit in the installation position without the use of screws and further comprises means for internally sealing the sensor unit with respect to the wheel and/or the gear box and/or the engine. 
     Embodiments of the present disclosure provide a sensor arrangement for a vehicle, which sensor arrangement comprises a sensor unit and a cable arrangement. The sensor unit comprises a main support and an electronic part having a sensor element, which electronic part is connected to the main support. In this case, the electronic part can be contacted in an electrical manner by way of at least one contact-making means to the cable arrangement, which contact-making means comprises at least one single conductor. In accordance with the disclosure, the main support is embodied as an open housing that comprises at least one insertion opening for receiving the at least one contact-making means and a receiving pocket for at least partial receiving the electronic part, wherein an elastic cap having means for fastening the sensor unit in the vehicle is provided, which elastic cap can be at least partially pushed over the main support that is embodied as a housing and which elastic cap closes the receiving pocket in a sealing manner. 
     Advantageous improvements of the sensor arrangement for a vehicle are rendered possible by way of the measures and further developments disclosed herein. 
     It is particularly advantageous, that the main support is embodied as a synthetic material injection molded part having a positioning lug. This renders it possible in an advantageous manner to assemble the sensor arrangement in a positionally-correct manner in the installation site in the vehicle. 
     In an advantageous embodiment of the sensor arrangement in accordance with the disclosure the at least one contact-making means comprises at least one first contact site for contacting the electronic part and at least one second contact site for contacting the cable arrangement. In this case, the at least one first contact site can be embodied by way of example as a welded connection and/or the at least one second contact site can be embodied as a crimped connection. 
     In a further advantageous embodiment of the sensor arrangement in accordance with the disclosure the at least one contact-making means is inserted with an end of a corresponding single conductor into an associated insertion opening, wherein the associated insertion opening is sealed by way of a single conductor seal that is mounted in an axial manner on the single conductor. Conductors having a casing and conductors that are injection molded in a sensor housing harbor the danger that moisture can pass along the conductors and/or the single conductors and penetrate the interior of the sensor unit, as a consequence of which corrosion can occur or malfunctions can arise. The use of individual conductors having single conductor seals prevents in an advantageous manner this type of moisture penetration which occurs as a result of leakage along the conductors. If a sheathed conductor is nonetheless required for reasons of strength and safety, then the casing is arranged around the single conductors at a sufficient distance from the sensor unit and fixed. 
     In a further advantageous embodiment of the sensor arrangement in accordance with the disclosure, the fastening means of the elastic cap comprises a stop surface that in the assembled state lies on an edge of an assembly opening of an assembly region. In addition or as an alternative thereto, the fastening means of the elastic cap can comprise an outwardly open groove that in the assembled state encompasses an edge of an assembly opening in the assembly region. 
     In a further advantageous embodiment of the sensor arrangement in accordance with the disclosure, the elastic cap comprises an internal sealing surface that together with a sealing bead that is arranged on the main support embodies an internal sealing region, in order to seal the sensor arrangement with respect to the installation site and in an advantageous manner to prevent moisture penetrating the receiving pocket of the main support. 
     In a further advantageous embodiment of the sensor arrangement in accordance with the disclosure, the elastic cap comprises an external sealing lip that together with a corresponding surface of an assembly opening embodies an external sealing region in order to seal the installation site with respect to the environment and in an advantageous manner to prevent any leakage on the vehicle equipment assembly in which the sensor arrangement is installed. 
     In a further advantageous embodiment of the sensor arrangement in accordance with the disclosure, the electronic part having the sensor element and a permanent magnet is embodied as an active sensor in the form of an application specific integrated circuit having a Hall element and/or a magneto-resistive element and an evaluating circuit or as a passively inductive sensor having a coil and a pole piece, wherein at least one contact connecting piece is provided for contacting the corresponding sensor element. 
     Exemplary embodiments are illustrated in the drawings and are further explained in the following description. In the drawings, like reference numerals indicate components and/or elements that perform like and/or similar functions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a schematic sectional view of a first exemplary embodiment of a sensor arrangement in accordance with the disclosure. 
         FIG. 2  illustrates a schematic illustration of a cable arrangement for the sensor unit in  FIG. 1  in accordance with the disclosure. 
         FIG. 3  illustrates a schematic illustration of the cable arrangement in  FIG. 2  having a mounted plug connector. 
         FIG. 4  illustrates a schematic lateral view of a main support for the sensor unit in accordance with the disclosure in accordance with  FIG. 1 . 
         FIG. 5  illustrates a schematic front view of the main support in  FIG. 4 . 
         FIG. 6  illustrates a schematic illustration of individual components of the sensor arrangement in accordance with the disclosure in  FIG. 1  prior to assembly. 
         FIG. 7  illustrates a schematic illustration of the sensor arrangement in accordance with the disclosure prior to mounting the elastic cap. 
         FIG. 8  illustrates a schematic sectional view of a second exemplary embodiment of a sensor arrangement in accordance with the disclosure. 
         FIG. 9  illustrates a schematic sectional view of a first installation region for the exemplary embodiments of a sensor arrangement in accordance with the disclosure in  FIG. 1 or 8 . 
         FIG. 10  illustrates a schematic sectional view of a second installation region for the exemplary embodiments of a sensor arrangement in accordance with the disclosure in  FIG. 1 or 8 . 
     
    
    
     DETAILED DESCRIPTION 
     As is evident in  FIGS. 1 to 7 , the illustrated first exemplary embodiment of a sensor arrangement  1  in accordance with the disclosure for a vehicle comprises a sensor unit  10 , a plug connector  40  and a cable arrangement  50 . The sensor unit  10  comprises a main support  12  and an electronic part  30  that is connected to the main support  12  and comprises a sensor element  34 . The electronic part  30  is contacted in an electrical manner by way of at least one contact-making means  37 ,  53  to the cable arrangement  50  that comprises at least one single conductor  52 ,  54 . 
     In accordance with the disclosure, the main support  12  is embodied as an open housing, which housing comprises at least one insertion opening  14  for receiving the at least one contact-making means  37 ,  53  and a receiving pocket  16  for at least partially receiving the electronic part  30 . Furthermore, an elastic cap  20  having means  24  for fastening the sensor unit  10  in the vehicle is provided, which elastic cap  20  is at least partially pushed over and/or pressed on to the main support  12  that is embodied as a housing and which elastic cap closes the receiving pocket  16  in a sealing manner. In the illustrated exemplary embodiment, the main support  12  is embodied as a synthetic material injection molded part having a positioning lug  18 , which positioning lug renders it possible to assemble the sensor arrangement  1  in a positionally-correct manner in the vehicle. 
     In the illustrated first exemplary embodiment, the electronic part  30  of the sensor arrangement  1  is embodied as an active sensor in the form of an application-specific integrated circuit (ASIC)  34  having a sensor element that is embodied as a Hall element and comprises an integrated evaluating circuit for preparing the measurement signals and outputting the measured value. The magnetic field for generating measurement signals is provided by a cylindrical permanent magnet  38  that is arranged according to the requirements of the magnetic circuit immediately adjacent to the ASIC-component  34 . Two conductors that are embodied as contact connecting pieces  36  are by-passed by a capacitor  32  in order to reduce signal spikes and are connected in an electrical manner by way of the at least one contact-making means  37 ,  53  to the single conductors  52 , 54  of the cable arrangement  50 . As a consequence, the electronic part  30  of the first exemplary embodiment of the sensor arrangement  1  is embodied as an ASIC-component  34  having two conductor connectors  37 ,  53 . The ASIC-component  34  is fastened by way of a “hot dip melting process” so that a hot dip melting spot  39  fastens the ASIC-component  34  to the main support  12  that is embodied as an open housing. The assembled permanent magnet  38  is preferably embodied as an NdFeB-magnet (neodymium iron boron magnet). 
     As is further evident in  FIG. 1 , the contact-making means in the illustrated exemplary embodiment comprises two first contact sites  37  for contacting the electronic part  30  and two second contact sites  53  for contacting the cable arrangement  50 , wherein the two first contact sites  37  are embodied as a welded connection and the two second contact sites  53  are embodied as a crimped connection. The contact connecting pieces  36  and the crimp connectors  55  of the second contact sites  53  preferably comprise the same material thickness, so that the ASIC-component  34  is welded by way of the contact connecting pieces  36  directly to the crimp connectors  55 . A strain relief is already integrated in the crimp connectors  55 , so that the loadings on the weld sites are reduced. The contact-making means  37 ,  53  in each case are inserted with an end of a corresponding single conductor  52 ,  54  into an associated insertion opening  14  of the main support  12 , wherein the associated insertion opening  14  is sealed by way of a single conductor seal  58  that is mounted in an axial manner on the single conductor  52 ,  54 . In a similar manner, the other ends of the single conductors  52 ,  54  are connected to corresponding crimp connectors  55  by way of crimped connections  53  and inserted and retained in corresponding insertion openings  44  in a housing  42  of the plug connector  40 . The single conductors  52 ,  54  are also sealed on the plug connector side in the insertion openings  44  in the housing  42  of the plug connector  40  by way of single conductor seals  58  that are mounted in an axial manner. In the illustrated exemplary embodiment, the single conductors  52 ,  54  of the cable arrangement  50  are twisted and are encased by a casing  56  that is illustrated by the dashed line and comprises a sufficiently large spacing with respect to the sensor unit  10  and the plug connector  40  in order to avoid moisture penetrating the sensor unit  10 . 
     As is further evident in  FIG. 1 , the elastic cap  20  comprises an internal sealing surface  23  that together with a sealing bead  19  that is arranged on the main support  12  embodies an internal sealing region D 1  in order to prevent moisture penetrating the receiving pocket  16 . 
     As is further evident in  FIG. 1 , the fastening means  24  of the elastic cap  20  comprises a stop surface  24 . 1  that in the assembled state lies on an edge of an assembly opening  5 . 1  of an assembly region  5  and embodies a fastening region B, as is evident in  FIG. 9 . Furthermore, the elastic cap  20  comprises an external sealing lip  22  that together with a corresponding surface of an assembly opening  5 . 1  embodies an external sealing region D 2 . The assembly region  5  illustrated in  FIG. 9  represents by way of example the assembly site on a vehicle wheel or on a vehicle motor. The second sealing region D 2  as a consequence seals the vehicle wheel and/or the vehicle motor with respect to the environment. 
     Alternatively, the fastening means  24  of the elastic cap  20  can comprise an outwardly open receiving groove  28  that in the assembled state encompasses an edge of an assembly opening  5 . 1 ′ in the assembly region  5 ′ and embodies a fastening region B′, as is evident in FIG.  10 . The outwardly open receiving groove  28  together with corresponding surfaces of the assembly opening  5 . 1 ′ simultaneously embodies an external sealing region D 2 ′. The assembly region  5  illustrated in  FIG. 10  represents by way of example the assembly site on a vehicle gear box. As a consequence, the second sealing region D 2 ′ seals the gear box with respect to the environment. 
     Embodiments of the present disclosure render possible a simple, cost-effective production process in an advantageous manner, which is described later with reference to  FIGS. 2 to 7 . 
     As is evident in  FIG. 2 , single cable seals  58  are arranged on the single conductors  52 ,  54  on the plug connector side end of the cable arrangement  50  for assembling the twisted cable arrangement  50 . The male crimp connectors  55  and the plug connector-side ends of the single conductors  52 ,  54  of the cable arrangement  50  are then crimped in order to produce corresponding crimped connections  53 . In a similar manner, single cable seals  58  are arranged on the sensor side end of the cable arrangement  50  on the single conductors  52 ,  54  of the cable arrangement  50 . The female crimp connectors  55  and the sensor-side ends of the single conductors  52 ,  54  of the cable arrangement  50  are then crimped in order to produce corresponding crimped connections  53 . 
     As is evident in  FIG. 3 , the male crimp connectors  55  for assembling the plug connectors  40  are inserted and retained in the insertion openings  44  in the housing  42  of the plug connector  40 . 
     As is further evident in  FIGS. 4 and 5 , the main support of the sensor unit  10  comprises two insertion openings  14 , the sealing bead  19 , the positioning lug  18  and the receiving pocket  16 , which main support is embodied as an open housing. 
     As is further evident in  FIG. 6 , the permanent magnet  38  is mounted in the main support  12  by way of being pressed into a corresponding receiving device. The cable arrangement  50  is assembled in the main support  12  by way of inserting the cable ends of the single conductors  52 ,  54  with the contact-making means  53  and crimp connectors  55  into the corresponding insertion openings  14  in the main support  12 , wherein the cable ends are inserted so far into the insertion openings  14  until said insertion orifices are sealed by way of the single conductor seals  58 . The bent-over ASIC component  34  having contacting connecting pieces  36  that have been cut to length are subsequently placed in a corresponding receiving pocket  16  and said ASIC component  34  is fastened by means of a hot dip melting process. Furthermore, the contact connecting pieces  36  of the ASIC-component  34  are welded to the female crimp connectors  55 . 
     As is evident in  FIG. 7 , the sensor unit  10  is sealed in a fluid-tight manner by means of pushing and/or pressing the elastic cap  30 , which is embodied for example as a rubber cap, on to the main support  12  that is embodied as an open housing. 
     As is evident in  FIG. 8 , the illustrated second exemplary embodiment of a sensor arrangement  1 ′ in accordance with the disclosure for a vehicle comprises a sensor unit  10 ′, a plug connector  40  and a cable arrangement  50 . The sensor unit  10 ′ comprises a main support  12 ′ and an electronic part  60  having a sensor element  64 , which electronic part  60  is connected to the main support  12 ′. The electronic part  60  is contacted in an electrical manner by way of at least one contact-making means  67 ,  53  to the cable arrangement  50  that comprises at least one single conductor  52 ,  54 . In the second exemplary embodiment, the main support  12 ′ is also embodied as an open housing that comprises at least one insertion opening  14 ′ for receiving the at least one contact-making means  67 ,  53  and a receiving pocket  16 ′ for at least partial receiving the electronic part  60 . In a similar manner to the first exemplary embodiment, an elastic cap  20 ′ having means  24 ′ for fastening the sensor unit  10 ′ in the vehicle is provided in the second exemplary embodiment, which elastic cap is at least partially pushed over and/or pressed on to the main support  12 ′ that is embodied as a housing and which elastic cap closes the receiving pocket  16 ′ in a sealing manner. In the illustrated exemplary embodiment, the main support  12 ′ is likewise embodied as a synthetic material injection molded part having a positioning lug  18 ′ that renders it possible to assemble the sensor arrangement  1 ′ in a positionally-correct manner in the vehicle. 
     In the illustrated second exemplary embodiment, the electronic part  60  of the sensor arrangement  1 ′ is embodied as a passive inductive sensor that comprises a sensor element, which is embodied as a coil  64  with a pole piece  62 , and a permanent magnet  68 . In this case, two contact connecting pieces  66  render it possible to connect the coil  64  in an electrical manner to the single conductors  52 ,  54  of the cable arrangement  50 . The assembled permanent magnet  68  is likewise preferably embodied as an NdFeB magnet (neodymium iron boron magnet). 
     As is further evident in  FIG. 8 , the contact-making means in the illustrated second exemplary embodiment in a similar manner to the first exemplary embodiment comprises two first contact sites  67  for contacting the electronic part  60  and two second contact sites  53  for contacting the cable arrangement  50 , wherein the two first contact sites  67  are likewise embodied as a welded connection and the two second contact sites  53  are embodied as a crimped connection. The contact connecting pieces  66  and the crimp connectors  55  of the second contact sites  53  comprise the same material thickness, so that the wires of the coil  64  are welded directly to the crimp connectors  55  by way of the contact connecting pieces  66 . A strain relief is already integrated into the crimp connectors  55 , so that the loads on the weld sites are reduced. The cable arrangement  50  and the plug connector  40  correspond in construction, in mode of operation and assembly fundamentally to the embodiments of the first exemplary embodiment and will therefore not be discussed in more detail here. 
     As is further evident in  FIG. 8 , the elastic cap  20 ′ comprises an internal sealing surface  23 ′ that in a similar manner to the first exemplary embodiment together with a sealing bead  19 ′ that is arranged on the main support  12 ′ embodies an internal sealing region D 1  in order to prevent moisture penetrating the receiving pocket  16 ′. In addition, the elastic cap  20 ′ comprises an inner adhesive site  26 ′ by means of which the pole piece  62  is adhered to the elastic cap  20 ′. 
     As is further evident in  FIG. 8 , the fastening means  24 ′ of the elastic cap  20 ′ comprise a stop surface  24 . 1 ′ that in the assembled state lies on an edge of an insertion opening  5 . 1  of an assembly region  5  and embodies a fastening region B, as is evident in  FIG. 9 . Furthermore, the elastic cap  20 ′ comprises an external sealing lip  22 ′ that together with a corresponding surface of an insertion opening  5 . 1  embodies an external sealing region D 2 . As a consequence, the second sealing region D 2  in the case of the second exemplary embodiment also seals the vehicle wheel and/or the vehicle motor with respect to the environment. 
     Alternatively, the fastening means  24 ′ of the elastic cap  20 ′ can comprise an outwardly open receiving groove  28  that in the assembled state encompasses an edge of an assembly opening  5 . 1 ′ in the assembly region  5 ′ and embodies a fastening region B′, as is evident in  FIG. 10 . The outwardly open receiving groove  28  together with corresponding surfaces of the assembly opening  5 . 1 ′ simultaneously embodies an external sealing region D 2 ′. As a consequence, in a similar manner to the first exemplary embodiment the second sealing region D 2 ′ seals the gear box with respect to the environment. 
     Embodiments of the present disclosure use simple components that are already commercially available. Thus, the housing that is used for the sensor unit is a housing that requires only one injection molding process for the production process. In addition, contact is provided by means of a welding process that welds corresponding contact connecting pieces of the sensor element directly to the crimp connections. It is thus in an advantageous manner not necessary to provide conductor rails in order to produce the electrical connection between the sensor element and the cable arrangement and/or the plug connector. The conductor inside the sensor unit is used to adjust the length for variations that have different functional extensions. Single conductor seals are used to seal the conductors with respect to the sensor housing, as a consequence of which it is possible to avoid the danger of moisture penetrating the sensor unit by way of leakages along the conductor. The elastic cap assumes the task of sealing of the engine, gear box and/or wheel with respect to the environment, and the tasks of fastening the sensor unit in the assembly position without the use of screws and internally sealing the sensor unit with respect to the engine, gear box and/or wheel. Embodiments of the present disclosure render it possible to reduce the production costs of the sensor arrangement by way of using the simplest production processes and connection techniques. As a consequence, embodiments of the present disclosure provide a sensor arrangement that in an advantageous manner can be produced using a simple cost-effective production process and can be mounted in the vehicle by way of a simple assembly process by the vehicle manufacturer without the use of a screwdriver. Furthermore, embodiments of the present disclosure use a housing for which only one injection molding process is required, and inexpensive, mass-produced sub-components.