Abstract:
An electrical motor connection, in particular of an electrical cooling fan motor for a motor vehicle, has a connected cable harness whose cable ends are connected to a motor-end connecting terminal. A connecting housing has two housing parts, which are joined together in the assembled state to form a cavity, and which hold connection-end cable ends of the cable harness. One of the housing parts has at least one filling opening, which opens into the cavity, for filling with a curable encapsulation compound, and with the cured encapsulation compound surrounding the cable ends in the area of the connecting terminal, and being joined to the housing parts.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation, under 35 U.S.C. §120, of copending international application No. PCT/EP2011/001497, filed Mar. 25, 2011, which designated the United States; this application also claims the priority, under 35 U.S.C. §119, of German patent application No. DE 20 2010 006 401.5, filed May 4, 2010; the prior applications are herewith incorporated by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The invention relates to an electrical assembly connection for a motor vehicle having a connected cable harness, the cable ends of the cable harness being connected to an assembly-end connection terminal. In this context, an assembly connection is understood to mean, in particular, an electrical motor connection, for example for a radiator fan motor of the motor vehicle. 
         [0003]    An assembly which is to be electrically connected to the on-board electrical supply system of a motor vehicle usually has a connection terminal (assembly interface) which is routed out of the housing of the assembly, the connection contacts (connection points) of the connection terminal being electrically insulated from one another and from the surrounding area. The assembly is generally electrically connected to the on-board electrical supply system of the motor vehicle by cables of a cable harness which is routed into an on-board electrical supply system cable, one cable or cable harness end of the cable harness having a plug connection, and the other cable or cable harness end thereof being electrically conductively connected to the assembly, which is to be supplied with power, by the connection terminals thereof. The electrical assembly connection of the individual cables of the cable harness with the connection terminal can be established by a welded connection, a solder connection, a clamping connection or a crimped connection. 
         [0004]    An assembly connection of this kind is also provided, in particular, in an electric motor which has connection cables and which is used, for example, as a drive for a radiator fan (radiator fan motor) for the motor vehicle. The radiator fan motor is operated by an electrical or electronic control circuit in order to adjust the required cooling power. The radiator fan motor is supplied with power by an on-board electrical supply system cable which is connected to a DC source (vehicle battery) of the motor vehicle. In this case, the cable ends of the cable harness, which is routed from the on-board electrical supply system cable, are connected to the connection terminal which virtually forms the motor interface to the electric motor used, this electric motor usually being electronically controlled. In this case, the cable harness generally contains, in addition to the power supply cables, that is to say the positive pole and the negative pole of the supply voltage, control cables and/or signal cables of an electronics system which controls the electric motor and/or processes detected motor data. During production of the electrical assembly connection or motor connection, electrical contact is usually made between the contacts (connection parts) of the connection terminal and the cable ends by welded connections. 
         [0005]    One problem with an assembly or motor connection of this kind is mechanical loading, in particular tensile loading, between the on-board electrical supply system cable, which contains the cable harness, and the connection terminal of the electric motor. Tensile loading of this kind can lead to damage or disconnection of the electrical contact at the assembly or motor connection. 
         [0006]    A further problem is presented by environmental influences such as temperature fluctuations and moisture which can lead to corrosion at the assembly or motor connection (connection terminal) with a high contact resistance or mechanical instability (loose contact). A short circuit which may occur across the assembly or motor connection can lead to damage in the on-board electrical supply system or in the assembly. Furthermore, the usually prescribed shock protection may be compromised. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention is based on the object of specifying a particularly secure and reliable assembly or motor connection which has a long service life. 
         [0008]    According to the invention, this object is achieved by the features of the claims. Advantageous refinements, developments and variants are the subject matter of the dependent claims which refer back to the main claim. 
         [0009]    Accordingly, an electrical assembly connection, in particular a motor connection of an electrical radiator fan motor, for a motor vehicle, having connected cables is provided, the cable ends of the cable being covered by a connection housing. In this case, the connection housing has two housing parts which are combined so as to form a hollow space in the assembled state and accommodate the connection-end cable ends of the cables of the cable harness. One of the housing parts, in particular a cover-like housing upper part, has at least one filling opening, which issues into the hollow space in the assembled state, for pouring in a curable encapsulation compound. 
         [0010]    The encapsulation compound is expediently a material with good adhesion properties, for example a silicone, polyurethane or a casting resin. Furthermore, one housing part has a venting opening. When pouring in the encapsulation compound, two or three filling openings, for example, allow the encapsulation compound to be distributed in the hollow space in the connection housing in a quick and uniform manner. Furthermore, one housing part has a venting opening. The venting opening allows rapid filling without disadvantageous air bubbles forming in the encapsulation compound. In the cured state, the encapsulation compound surrounds the electrical assembly or motor connection within the connection housing and is joined to the housing parts in a virtually undetachable manner—in the sense of adhesive bonding. The connection housing therefore advantageously remains permanently on the assembly or motor connection, that is to say is a permanent constituent part thereof. 
         [0011]    In an advantageous development, one of the housing parts contains at least one cable bushing which has a conical guide inner contour which opens in the direction of the connection terminal, a clamping part resting against the guide inner contour. As a result of tensile loading on the cable harness, the clamping part slides along the corresponding guide inner contour, with the result that the clamping action on the corresponding cable increases as the tensile loading increases. The corresponding housing part preferably has two cable bushings of this kind for the current-carrying cables (positive pole cables and negative pole cables) with conical guide inner contours which interact with corresponding clamping parts. 
         [0012]    In an expedient refinement of the assembly or motor connection, only one of the housing parts is in the form of a shell, while the other housing part is then configured as a housing cover. In addition, both housing parts can be configured as housing half-shells. The housing lower part, which has the guide inner contours, is preferably in the form of a shell, while a cover-like housing upper part is fitted with the corresponding clamping parts. Whereas the number of guide inner contours and clamping parts appropriately corresponds to the number of supply cables, the control or signal cables can be situated, at the connection end, in the connection housing without cable guidance of this kind. To this end, the control or signal cables are configured to be longer, and therefore project further into the connection housing than the power supply cables which are relieved of tensile load by clamping parts, and are thus protected on account of tensile forces being absorbed by the cables which are relieved of load by the clamping parts. 
         [0013]    The clamping part rests against the respective cable and has a conical or wedge-like outer contour which tapers away from the connection terminal, that is to say in the opposite direction to the connection terminal, and rests against the guide inner contour. Furthermore, one of the housing parts has at least one fixing element which engages in an interlocking manner in a corresponding collar contour of the assembly or motor housing in the region of the connection terminal in the assembled state. 
         [0014]    Insertion of the cables of the cable harness is simplified by virtue of the shell-like and cover-like configuration of the housing parts. The connection between the connection housing-end fixing element and the assembly-end collar contour ensures that the connection housing is held on the assembly or on the motor housing in a particularly simple and effective manner, in particular in the event of tensile loading between them. Furthermore, the interlocking connection between the two-part connection housing and the assembly facilitates uniform and correct positioning of the connection housing by providing guidance when fitting the housing lower part. 
         [0015]    The guide inner contour and the clamping part, which are configured in a conical or wedge-shaped manner in particular, create a particularly effective force-fitting or frictional connection since the holding forces act radially on the cables in the event of tensile loading and increase as the tensile force increases. In particular, the combination and arrangement of the interlocking connection between the connection housing and the assembly and the tensile force-dependent cable clamping ensure reliable relief of tensile loading, with the result that electrical contact between the cables and the electrical assembly by the on-board electrical supply system cable is reliably maintained in the event of tensile loading. 
         [0016]    The housing parts are locked to one another in the assembled state, wherein the assembled housing parts at least partially engage over the assembly or motor connection and, in this case, in particular the connection terminal with the cable ends with which contact is made at the connection points of the connection terminal. Furthermore, one of the housing parts, in particular the shell-like housing lower part, has spacer elements which project into the hollow space. The cables of the cable harness are arranged between the spacer elements in the assembled state of the connection housing. The spacer elements prevent unintentional movement of the cables. On account firstly of the housing parts being locked and secondly of the assembled housing parts being engaged over in the region of the connection terminal, the hollow space which is formed from the housing parts is tightly surrounded, as a result of which the encapsulation compound is prevented from leaking during filling and curing. As a result of leakage being prevented, further process or processing steps can be performed as early as during curing of the encapsulation compound, as a result of which the cycle time and the costs of production of the assembly or of the radiator fan motor are reduced. 
         [0017]    This is advantageously achieved by the two-part, assembled connection housing remaining on the electrical assembly or on the electric motor, with the result that the encapsulation is shaped during curing without additional tools. The material of the connection housing, which virtually serves as a container for the encapsulation compound, and the material of the insulation of the connection terminal of the assembly or of the electric motor should have good adhesion properties in relation to the encapsulation material used. The material of the connection housing (container) should ideally correspond to the encapsulation material of the connection terminal. 
         [0018]    The impermeability of the connection or of the connection points to moisture is ensured by virtue of the components (connection housing and connection terminal) being adhesively bonded to one another. At the same time, this determines the mechanical stability and the shape of the encapsulation material. On account of the encapsulation compound which has an appropriately low viscosity being poured into the connection housing which surrounds the connection region, the assembly can be transported further when the encapsulation compound is still in the largely highly fluid, uncured state, with the result that the further process steps can be executed as the curing time elapses. This means that it is not necessary to wait until the encapsulation compound is dimensionally stable in the further process sequence. This leads to a significant reduction in the manufacturing time required for the encapsulation and the further processing of the assembly. At the same time, reliable relief of tensile loading on the connection points of the cables is provided by the configuration of the connection housing in conjunction with the configuration of the connection region of the assembly or of the electric motor or of a drive which contains one of these elements. 
         [0019]    Surrounding the assembly or motor connection with encapsulation compound in the manner of a seal and joining the housing parts of the connection housing to the cured encapsulation compound ensure particularly effective protection against environmental influences and mechanical loading. The fluid encapsulation compound being distributed around the connection terminal and the cable ends which make contact with the connection terminal and, in the process, within the connection housing provides a high degree of flexibility virtually independently of the shape of the assembly or motor connection. 
         [0020]    Other features which are considered as characteristic for the invention are set forth in the appended claims. 
         [0021]    Although the invention is illustrated and described herein as embodied in an electrical assembly connection of a motor vehicle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0022]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0023]      FIG. 1  is a diagrammatic, perspective view of a motor connection of an electric radiator fan motor, having cables of a on-board electrical supply system cable which are connected to the motor connection and having a connection housing which is filled or can be filled with encapsulation compound according to the invention; 
           [0024]      FIG. 2  is a diagrammatic, perspective view of the radiator fan motor with a view of a connection terminal without a connection housing; 
           [0025]      FIG. 3  is a diagrammatic, exploded perspective view of the connection housing containing a cover-like housing upper part and a shell-like housing lower part; 
           [0026]      FIG. 4  is a perspective view of the connection housing containing the cover-like housing upper part and the shell-like housing lower part in an assembled state; 
           [0027]      FIG. 5  is a diagrammatic, plan view of the motor connection with cable ends with which contact is made at contact points of the connection terminal and with the housing lower part mounted; 
           [0028]      FIG. 6  is a diagrammatic, plan view of the motor connection with the cable harness connected in accordance with  FIG. 5  in a view of the mounted connection housing from below; and 
           [0029]      FIG. 7  is a diagrammatic, sectional view which is sectioned parallel to the plane of the drawing of  FIG. 6 , of the motor connection with the connection housing attached and with individual cables clamped as a tensile loading-relief arrangement. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    Parts which correspond to one another are provided with the same reference symbols in all the figures. 
         [0031]      FIG. 1  shows a perspective illustration of an electrical motor connection  1  of a DC radiator fan motor (electric motor)  2  having power supply cables  3  and signal or control cables  4  of a cable harness  5  of an on-board electrical supply system  6  connected to it. The on-board electrical supply system  6  is fitted with a plug connector  7  at an end which is remote from the radiator fan motor  2 . A connection housing  8  which is filled with encapsulation compound surrounds a connection terminal (not shown here) of the radiator fan motor  2 . Due to the required current-carrying capability, the power supply cables  3  have a comparatively large cable diameter in relation to the control or signal cables  4 . Instead of the radiator fan motor  2 , a different electrical assembly with connected cables can also form the connection as the assembly connection  1 . 
         [0032]      FIG. 2  shows a perspective view of the radiator fan motor  2  with a view of a connection terminal  9  of the radiator fan motor having a number of connection contacts (connection points)  10  and  11  which corresponds to the number of power supply and signal or control cables  3  and  4 . The connection terminal  9  forms a kind of motor interface which is firstly connected to an electronics system  12  of the radiator fan motor  2 , the connection contacts  10 ,  11  of the connection terminal or motor interface being formed by a stamped sheet-metal comb which is composed of sheet copper. The conductor ends of the cables  3 ,  4 , which conductor ends are connected to the connection contacts or points  10 ,  11  and therefore to the connection terminal  9 , in particular which are electrically conductively contacted by welding, form the motor connection  1 . 
         [0033]    During operation of the radiator fan, the radiator fan motor  2  is supplied with direct current by the power supply cables  3  which are connected to the vehicle battery in a manner which is not described in any detail. The control or signal cables  4  are used to control the motor  2  or to interchange data with the radiator fan electronics system  12  and a vehicle electronics system. For example, control instructions are transmitted from the motor vehicle electronics system to the radiator fan motor  2  or operating information about the radiator fan motor  2 , for example the rotation speed, is transmitted to the motor vehicle electronics system  12  by the control and signal cables  4  during operation of the radiator fan. 
         [0034]    Adjacent to the cable ends of the cables  3 ,  4 , the connection terminal  9  is provided in regions with an insulating encapsulation  13  comprising polybutylene terephthalate (PBT) which surrounds the connection contacts  10 ,  11  in a subregion. The encapsulation  13  has a collar or interlocking contour  14  on both sides of the connection terminal  9 . 
         [0035]      FIGS. 3 and 4  show perspective views of a connection housing  8  with a cover-like housing upper part  8   a  and a shell-like housing lower part  8   b  in the unattached state and, respectively, in the assembled state. The two housing parts  8   a  and  8   b  are produced from a thermoplastic, for example from polybutylene terephthalate (PBT). The shell-like housing lower part  8   b  has conical guide inner contours  16  in the region of cable bushings  15  for the power supply cables  3 . 
         [0036]    Two cable bushings  17  for the control and signal cables  4  in the housing lower part  8   b  are located between the two outer cable bushings  15  for the power supply cables  3  along the x-direction with respect to the illustrated coordinate system. In addition, three dome-like spacer elements  18  are integrally formed on the floor of the housing lower part  8   b  in the insertion directions, which run in the y-direction, for the cables  3 ,  4  in the exemplary embodiment. In the case of cable ends of the cables  3 ,  4  being situated in the connection housing  8 , the spacer elements run between the cable ends and project into a hollow space  19  which is formed between the housing upper part  8   a  and the housing lower part  8   b.    
         [0037]    Furthermore, the housing lower part  8   b  has fixing elements  20 , which are integrally formed on the inside of that housing face which is situated opposite the cable bushings  15 ,  17 , on those housing walls  21  of the housing lower part  8   b  which are situated opposite in the x-direction. The housing lower part  8   b  also has two latching recesses  22  on the housing walls  21  which are situated opposite one another. Latching hooks  23  which are integrally formed on the housing cover  8   a  engage in the latching recesses  22 .  FIG. 4  shows the state of the connection housing  8  in which it has been assembled by the latching connection  22 ,  23  so as to form the hollow space  19 . 
         [0038]    Recesses  24  which are integrally formed in the housing upper part  8   a  form a continuation of the cable bushings  15  to form a circular shape in the assembled state of the connection housing  9  which is shown in  FIG. 4 . A recess  26  which is integrally formed between the recesses  24  and is angular in the exemplary embodiment closes off the cable bushing  17  for the control or signal cables  4  in order to form a bushing  17  which is closed at the circumference. 
         [0039]    The housing upper part  8   a  additionally has three filling openings  26  which are arranged approximately centrally and also a venting opening  27  in the region of each of the latching hooks  23 . The filling openings  26  are used to fill the hollow space  19  of the connection housing  8  with an encapsulation compound when cable ends of the cables  3 ,  4  are situated in the hollow space and are connected to the connection terminal  9 . The venting openings  27  allow the air which is displaced when the encapsulation compound is poured in to escape rapidly. Clamping parts  28  are integrally formed, such that they can pivot at least slightly, on the housing upper part  8   a  in the region between the latching hooks  23  and the cable bushings  15  in the x-direction at the housing edge. 
         [0040]      FIG. 5  shows a plan view of the motor or assembly connection  1  in the region of the connection terminal  9  with cable ends of the cables  3  and  4  with which contact is made at the connection contacts  10 ,  11 —for example by welded connections—when the housing lower part  8   b  is fitted but the housing upper part  8   a  is not. It can be seen that the fixing elements  20  engage in an interlocking manner in the collar contour  14  of the connection terminal  9 . As can likewise been seen, the spacer elements  18  which project upward between the connection cables  3 ,  4  ensure reliable positioning of the cable ends of the cables  3  and  4  and reliably prevent the cable ends unintentionally coming into contact with one another. The guide inner contours which taper conically in the y-direction and are also open in the direction of the connection terminal  9  rest against the cables  3 . 
         [0041]      FIG. 6  shows the motor or assembly connection  1  in a view of the connection housing  8  from below, the hollow space  19  in the connection housing being completely filled with encapsulation compound (not shown). The power supply cables  3  and the signal cables  4  are completely surrounded by the cable bushings  15  and  17 . The connection housing  8  is closed off in the region of the connection terminal  9  by way of its encapsulation  13 . 
         [0042]      FIG. 7  shows the motor or assembly connection  1  with the mounted connection housing  8  in section in the y-direction along the center plane of the power supply cables  3 . It can be seen that the fixing elements  20  of the housing lower part  8   b  engage in the corresponding collar contour  14  of the encapsulation  13  of the connection terminal  9 . The clamping parts  28  which are integrally formed on the housing upper part  8   a  are provided with a conical or wedge-like outer contour  29  on that face of the housing upper part  8   a  which faces the respective guide inner contour  16 , the respective clamping part  28  resting on the corresponding guide inner contour  16  by way of the outer contour. In addition, the respective clamping part  28  rests in a force-fitting or frictional manner on the corresponding power supply cable. 
         [0043]    The guide inner contours  16  of the housing lower part  8   b,  which guide inner contours tapers in the y-direction and therefore in the opposite direction to the connection terminal  9 , and clamping part outer contours  29  of the housing upper part  8   a  slide on one another in the manner of a ramp, that is to say in the manner of an oblique plane, in the y-direction when the cable harness  3 ,  4  or the on-board electrical supply system cable  6  is subjected to tensile loading. On account of the resulting force component, which is produced as a result of the tensile loading in the y-direction transverse to this in the x-direction, an action of force which increases as the tensile force increases is exerted on the cables  3 , with the result that the power supply cables  3  are held virtually immobile by the connection housing  8  virtually in the conductor longitudinal direction y. 
         [0044]    This relief of tensile loading is effective and therefore particularly advantageous at least for as long as the encapsulation compound which is poured into the connection housing  8  has not yet cured or has not yet completely cured. This in turn has the considerable advantage that, even while the curing process for the encapsulation compound is not yet completed, the assembly or the radiator fan motor  2  with the cable harness  3 ,  4  already connected and contacted, and therefore with the on-board electrical supply system cable  6  connected, can be supplied to a further production or manufacturing process without the resulting movement having a disadvantageous effect on the attached connection  1 . After the encapsulation compound has cured, it is reliably attached to the connection terminal  9  and to the connection housing  8  with a good adhesive bond and is protected against moisture and other environmental influences with a particularly long service life against operation-related mechanical loading. 
       LIST OF REFERENCE SYMBOLS 
       [0000]    
       
           1  Motor/assembly connection 
           2  Radiator fan motor 
           3  Power supply cable 
           4  Signal cable 
           5  Cable harness 
           6  On-board electrical supply system cable 
           7  Plug connector 
           8  Connection housing 
           8   a  Housing upper part 
           8   b  Housing lower part 
           9  Connection terminal 
           10  Connection contact/point 
           11  Connection contact/point 
           12  Motor/assembly electronics system 
           13  Encapsulation 
           14  Collar contour 
           15  Cable bushing 
           16  Guide inner contour 
           17  Cable bushing 
           18  Spacer elements 
           19  Hollow space 
           20  Fixing element 
           21  Housing wall 
           22  Latching recess 
           23  Latching hook 
           24  Recess 
           25  Recess 
           26  Filling opening 
           27  Venting opening 
           28  Clamping part 
           29  Clamping wedge outer contour