Abstract:
A housing for an electrical machine includes a cover with an electrical plug connection. The plug connection includes at least one electrically conductive contact or a plurality of electrically conductive contacts configured to electrically connect the housing to a plug. The contact is routed through an aperture in the cover and forms an electrical plug contact via an end section that projects out of the cover. The plug connection has a securing element that extends in a flat manner. A lateral dimension of the aperture in the cover is formed such that the contact is routed through the aperture via the end section and engages behind a projection in an interlocking manner by virtue of moving transverse to the longitudinal extent in the aperture. The securing element has at least one aperture that is configured to fix the contact in the aperture transverse to a longitudinal extent of the contact.

Description:
This application claims priority under 35 U.S.C. §119 to patent application no. DE 10 2012 223 431.4 filed on Dec. 17, 2012 in Germany, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     The disclosure relates to a housing for an electrical machine. The housing has a cover, wherein the cover has an electrical plug connection comprising at least one electrically conductive contact, in particular a plug contact, or a plurality of electrically conductive contacts for electrically connecting the housing to a plug. 
     In housings for an electrical machine which can come into contact with splash water, it is necessary for both the electrical contacts and also the electrical components in the interior of the housing to be protected against penetrating moisture. 
     In embodiments of the housing in which the electrical plug contacts, which form an outer electrical connection for connecting the housing to a plug and which are routed to the outside through an aperture in the housing, can form a weak point for penetrating moisture in this case, said penetrating moisture being able to pass through a gap between the housing wall in the region of the aperture for the plug contact and the plug contact and into the interior of the housing. 
     SUMMARY 
     According to the disclosure, the at least one contact is routed through an aperture in the cover, wherein the contact forms an electrical plug contact by way of an end section which projects out of the cover. The plug connection has a securing element which extends in a flat manner. 
     A lateral dimension of the aperture in the cover is preferably formed in such a way that the contact can be routed through the aperture by way of the end section and can engage behind a projection in an interlocking manner by virtue of moving transverse to the longitudinal extent in the aperture. 
     The securing element has at least one aperture for the at least one contact and is designed to fix the at least one contact in the aperture transverse to a longitudinal extent of the contact. 
     As a result, the contact can be firmly held in the aperture in a simple manner. 
     In a preferred embodiment, a plug collar is integrally formed on the cover, wherein the end section of the at least one contact projects into a hollow space which is enclosed by the plug collar. The securing element is preferably designed to be supported against the plug collar and in this way to fix the at least one contact in the aperture transverse to its longitudinal extent of the contact. In this way, the securing element advantageously forms a fixing apparatus for the plug contact. 
     The plug contact can be designed, for example, in a T- or L-shaped manner in the region of the cutout. 
     Furthermore, by means of the locking arrangement formed in this way, a force which is as low as possible can advantageously be exerted on the plug contact in its longitudinal direction during insertion and during locking. Therefore, a printed circuit board which is connected to the plug contact can advantageously not be subjected to loading, or will be subjected to only slight loading, when the housing cover is fitted onto the plug contacts. The contact pin can advantageously be held in the locked position by means of the abovementioned contact-pressure element, in particular a contact-pressure plate. 
     The plug connection preferably has an elastic seal which extends in a flat manner, wherein the end section is routed between the cover wall and one end of the end section through an aperture in the seal. 
     The securing element is preferably designed to press the seal against the cover and in this way to seal off the aperture. 
     By virtue of the seal of the housing, which seal is formed in this way, the gap which remains between the plug contact and the wall of the housing in the region of the aperture can advantageously be sealed off in one working step, specifically when the flat seal is pushed onto the end section of the plug contact. In a further step or together with the abovementioned seal, the abovementioned securing element can be pushed onto the plug contact, in particular onto the end section, and press the seal, in its flat extent, against the housing wall in the region of the aperture. In this way, the securing element also forms a constituent part for sealing off the gap between the plug contact and the housing wall in the region of the aperture. 
     In a preferred embodiment of the housing, the at least one contact has a recess in a longitudinal section, wherein the cover has a projection region in the region of the aperture, said projection region corresponding to the recess. The projection region is designed to engage in the cutout and to secure the contact in an interlocking manner against moving along the longitudinal extent in the aperture. In this way, the plug contact can advantageously be locked after the end section is inserted into the aperture, wherein the projection engages in the cutout in the plug contact during locking. 
     In a preferred embodiment of the housing, the seal is connected to the securing element. The seal is adhesively bonded to the securing element by means of an adhesive for example. 
     In another embodiment, the seal is plug-connected to the securing element. To this end, the securing element preferably has a projection region which extends transverse to the flat extent of the contact-pressure element and which is designed to engage in a cutout and/or in an aperture in the seal which extends in a flat manner, and in this way to form a connection with the seal in a force-fitting and/or interlocking manner. 
     In a preferred embodiment of the housing, the seal is extruded onto the securing element. In this way, one production step, specifically that of fitting the contact-pressure element onto the at least one contact after the seal is fitted, can advantageously be saved. 
     In a preferred embodiment of the housing, the cover has a tapering insertion funnel in the region of the aperture, said insertion funnel being designed to receive the end section of the contact when it is inserted into the aperture and to route said end section—in particular by way of a component which is transverse to its longitudinal extent—into the aperture. In this way, it is advantageously made easier to fit the cover onto the plug contact, in particular onto a plurality of plug contacts which are connected to the abovementioned printed circuit board. 
     The disclosure also relates to a method for fixing at least one contact, in particular a plug contact in a cover for a housing, in which method an end section of the contact is routed through an aperture in the cover and is moved transverse to its longitudinal extent in the aperture, wherein a projection region in the aperture engages in a cutout in the contact and locks the contact in an interlocking manner against moving along the longitudinal extent in the aperture. 
     In the method, the end section, after being routed through the cover, is preferably further routed through an aperture for the end section of an elastic seal which extends in a flat manner. Furthermore, the end section is routed through a securing element which extends in a flat manner, in particular a contact-pressure plate, and has an aperture for the end section at the end section, wherein the securing element presses the seal against the cover and in this way seals off the aperture of the cover—in particular against penetrating moisture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will now be described below with reference to figures and further exemplary embodiments. Further advantageous variant embodiments are disclosed by the features described in the figures and in the dependent claims. 
         FIG. 1  shows an exemplary embodiment of a housing comprising a sealed-off plug connection comprising a flat seal and a flat contact-pressure plate as a securing element for the flat seal; 
         FIG. 2  shows a plan view of the plug connection, said plan view also showing the apertures for the contacts, which are illustrated in  FIG. 1 , of the plug connection in cross section; 
         FIG. 3  shows a sectional illustration through the plug connection which is illustrated in  FIG. 1 , wherein insertion of the contact into the aperture as the first method step for generating the plug connection is also shown; 
         FIG. 4  shows further method steps in which the seal and the contact-pressure plate are fitted onto the contact; and 
         FIG. 5  shows a portion of the contact-pressure plate which is shown in  FIGS. 1 and 4  and of the flat seal in detail. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an exemplary embodiment of a housing  1  for an electric motor. The electric motor is, for example, an electric motor for a power-steering system. The housing  1  has a cover  2 . The cover  2  is, for example, a plastic cover. A plug collar  3  is integrally formed on the cover  2 . The plug collar  3 , together with a base  4 , forms a plug connection for a plug  39 , which is partially illustrated, in the region of a hollow space which is enclosed by the plug collar  3 . 
     The electric motor is designed to be electrically connected toward the outside by means of the plug connection. To this end, the plug connection has at least one electrically conductive contact, in this exemplary embodiment three electrically conductive contacts  7 ,  8  and  9 . The electrically conductive contacts  7 ,  8  and  9  each project by way of an end section  50 , which extends along a longitudinal section  10 , into the hollow space which is enclosed by the plug collar  3 . The contacts  7 ,  8  and  9  are each routed through an aperture  22 ,  23 , and  24 , respectively, (shown in  FIG. 2 ) in the base  4 . The apertures in the base  4  are illustrated in greater detail in  FIG. 2 . 
     The plug  39  has a mating contact  40 ,  41  and, respectively,  42  for each of the contacts  7 ,  8  and  9 , wherein the mating contact is designed to make sliding electrical contact with the end section  50 . 
     The contacts  7 ,  8  and  9  each have a recess  51  in a longitudinal section  11  which adjoins the end section  10 . In this way, the contacts  7 ,  8  and  9  can—as illustrated in greater detail in  FIG. 2 —be moved transverse to their longitudinal extent after the end section is routed through the aperture in the base  4  and said contacts can be secured in an interlocking manner against moving back through the aperture. 
     In this exemplary embodiment, the contacts  7 ,  8  and  9  are in the form of plug contacts which are to be connected to a plug, in particular to the plug  39 . The contacts  7 ,  8  and  9  each have a meandering section  18  which extends between the longitudinal section  11  and an end section  15  which is designed to be electrically connected to a printed circuit board. The meandering section  18  of the contact  9  and the end section  15  of the contact  9  are identified by way of example. The contact  9  is soldered in the printed circuit board  6  by way of the end section  15  for example. In this exemplary embodiment, the printed circuit board  6  forms a circuit mount for the control electronics system of the abovementioned electric motor. A microprocessor  13  and a capacitor  14  are connected to the printed circuit board by way of example. 
     The electric motor has a motor housing  20  and a rotor  21  which is accommodated by the motor housing  20 . The rotor  21  is, for example, of permanent-magnet design and is connected to a rotor shaft  19  which can be connected to a gear mechanism by way of an end section which projects out of the housing  20 . 
     The printed circuit board  6  is accommodated in a hollow space  5  which is enclosed by the cover  2 . 
     The contacts  7 ,  8  and  9  are each routed through an elastic seal  16  which extends in a flat manner, for example a silicone rubber seal, at the end section  50 . The housing  1  also has a securing element  17  which extends in a flat manner and which is in the form of a contact-pressure plate in this exemplary embodiment. The contacts  7 ,  8  and  9  are at least partially routed through the securing element  17  by way of the end section  50 , so that the seal  16  and the securing element  17  are arranged along a longitudinal extent  30  of the contact element between one end  12  of the end section  50  and the base  4  of the plug connection. 
     The seal  16  and the securing element  17  each have an aperture—illustrated in greater detail in  FIG. 4  and in  FIG. 5 —for the end sections  10  of the contacts  7 ,  8  and  9 . 
     The meander  18  is designed to counteract a force, which acts along a longitudinal extent of the contact  9 , in a spring-like manner, so that the electrical connection between the end section  15  and the printed circuit board  6  can be relieved of force. 
       FIG. 2  shows a plan view of the plug connection of the housing  2  which has already been illustrated in  FIG. 1 , in particular the plug collar  3  and the base  4  of the plug connection. The base  4  of the cover  2  has three apertures  22 ,  23  and  24 . The contact  7  illustrated in  FIG. 1  is routed through the aperture  22 , the contact  8  is routed through the aperture  23 , and the contact  9  is routed through the aperture  24 . The apertures  22 ,  23  and  24  each have at least one projection region, in this exemplary embodiment two projection regions, wherein the projection regions  28  and  29  on the aperture  22  are identified by way of example. The contact  7  can be fitted when the cover  2  is fitted onto the contacts  7 ,  8  and  9  which are already connected to the printed circuit board  6 . In the process, the end section  50  of the contact  7  passes through the aperture  22  in the region  26  of the aperture. Once the end section  50  has been routed through the aperture  22  in the region  26 , the contact  7  can be moved into a region  25  of the aperture  22  by way of the end section  50 , as a result of which the contact  7 —by virtue of its T-shape—is secured in an interlocking manner against moving back through the aperture  22 . 
       FIG. 3  shows a sectional illustration through the plug connection which has already been illustrated in  FIGS. 1 and 2 . Said figure shows the contact  7  which is routed through the aperture  22  in the base  4  of the cover  2  by way of its end section  50 . The cover  2  is designed to make it easier to insert the end section  50  of the contact  7  through the aperture  22 . To this end, the cover  2  has an insertion funnel  27  in the region of the plug connection, in particular in the region of the base  4 . The insertion funnel  27  is of tapering design along a longitudinal extent of the aperture  22  which extends transverse to a flat extent of the base  4 . As illustrated in  FIG. 3 , the end section  50  of the contact  7  can be routed through the aperture  22  in a method step in order to be connected to the cover  2 . 
       FIG. 4  shows further method steps for connecting the cover  2  to the contact  7  and for sealing off the aperture  22 . After the end section  50  of the contact  7  has been routed through the aperture  22 , the contact  7  can be pivoted transverse to its longitudinal extent  30  in direction  33 . In the process, the end section  50  engages behind the projection regions  28  and  29 . After said contact has been pivoted transverse to the longitudinal extent  30  in direction  33 , the seal  16  can be fitted onto the contact  7 . To this end, the end section  50  of the contact  7  is routed through an aperture  32  in the seal  16 . In this exemplary embodiment, the aperture  32  has a smaller diameter than the contact  7  in the region of the end section  50 . In this way, the seal  16  is elastically expanded in the region of the aperture  32  and can provide sealing in relation to the contact  7 . After the seal  16  is fitted onto the contact  7 , the securing element  17  which has already been described in  FIG. 1  and which has on the aperture  31  for the plug contact  7  can be plugged onto the plug contact  7 . To this end, the contact  7  is routed through the aperture  31  by way of the end section  50 . 
     The securing element  17 , which is in the form of a contact-pressure plate in this exemplary embodiment, can be pressed against the seal  16 , for example, by virtue of the plug  39  which is illustrated in  FIG. 1  being fitted onto the plug connection or locked—by way of the plug collar  3 , in particular cutouts in the plug collar  3 . After the contact-pressure element  17  is fitted, the contact  7  is secured against moving back counter to the direction  33 , that is to say from the region  25  of the aperture  22  to the region  26  of the aperture  22 . Therefore, the securing element  17  advantageously has two different functions, specifically that of pressing the seal  16  against the base  4  in order to seal off the aperture  22 , and of securing the contact  7  in an interlocking manner against moving out of the aperture  22 . 
       FIG. 5  shows portions of the seal  16  which has already been illustrated in  FIGS. 1 and 4  and of the securing element  17 . The seal  16  which extends in a flat manner has a sealing lip  35  which can provide sealing in relation to the plug collar  3 . Said figure also shows the aperture  32  in the seal  16  and the aperture  31  in the securing element  17 . In this exemplary embodiment, the securing element  17  has projection regions which extend toward the outside radially in the flat extent, the projection  34  of said projection regions being identified by way of example. In this exemplary embodiment, the projections like the projection  34  can serve as positioning aids for the contact-pressure element  17  or—in addition to or independently of the function as a positioning aid—can lock in a corresponding cutout  36 , which is illustrated in  FIG. 4 , in the plug collar  3 . 
     In this exemplary embodiment, the securing element  17  has an aperture  37  which is designed to receive a cam  38  of the seal  16 , wherein the cam  38  is integrally formed on the seal  16  and extends transverse to the flat extent of the seal  16 . In this way, the seal  16  can be connected in a force-fitting manner to the securing element  17  after the cam  38  engages in the aperture  37 . 
     In contrast to the illustration in  FIG. 5 , the seal  16  can be extruded onto the securing element  17 . As a result, one production step, specifically that of additionally fitting the contact-pressure element  17  onto the contacts  7 ,  8  and  9 , can be dispensed with.