Abstract:
The invention relates to a bearing shield ( 5 ) for an electrical motor having a rotor and a stator, wherein the bearing shield ( 5 ) has a receptacle ( 25 ) for a bearing ( 400 ) for bearing a shaft of the rotor ( 100 ) and wherein the bearing shield is arranged in a housing ( 35 ) of an electrical motor, wherein the bearing shield has a current carrier ( 13, 23, 24, 60 ) which is configured to connect at least one coil ( 74 ) of the stator to a power connection or to another coil ( 74 ) of the stator.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to an endshield for an electric motor with a rotor and a stator, the endshield having a receptacle for a bearing for the bearing arrangement of a shaft of the rotor, and the endshield being arranged in a housing of the electric motor. 
     A large number of endshields in electric motors are known. DE 201 19 108 U1 has disclosed an electric motor with an endshield which has a bearing face for at least one component, in particular a coil. The coils are connected to a connection plug by means of cables. In this case, the cables are passed through the endshield into the interior of a housing of the electric motor by means of a cable bushing. The endshield also has a bearing face with a disk, the bearing face and the disk serving to fasten further component parts, whereby the ventilation of the electric motor should not be restricted. 
     In addition, EP 1 024 581 B1 has disclosed an electric motor and a method for making contact between windings of an electric motor, the windings being wound in such a way that the wire ends of the windings leave the windings at a rear end side. In addition, a contact carrier is arranged at the end side of the windings, with the wire ends of the windings being guided to said contact carrier and are grasped by a gripper of the contact carrier which is equipped with a receiving device in the form of a comb or a fork as thread-in aid in order to receive the wire ends. In this case, at least two of the wire ends are brought together by the gripper on an end side of the contact carrier. In addition, the ends of the windings on the end side of the contact carrier are conductively connected to one another by means of an insulation displacement contact. In this case, the windings are part of the stator. In addition, the rotor is mounted via a bearing which is arranged in the housing and via a bearing which is arranged in an endshield. 
     SUMMARY OF THE INVENTION 
     The object of the present invention consists in providing an endshield for an electric motor which has a simple design and makes optimum use of the installation space for an electric motor. 
     In accordance with the invention, it has been identified that the endshield can have a particularly simple design and provides an interior of the electric motor which is optimized in terms of installation space by virtue of the endshield having a power supply line, which connects at least one winding of the stator to an electrical connection and/or to a further winding of the stator. 
     This has the advantage that the function of the endshield, namely the bearing arrangement of the shaft of the rotor, and the function of a contact plate, namely interconnecting the individual windings of the stator of the electric motor, are combined in one assembly, with the result that optimum use is made of the installation space in the interior of an electric motor and the fitting time during fitting of the electric motor is reduced. 
     In a further embodiment of the invention, the power supply line has a first contact face and a second contact face, the first contact face being connected to the electrical connection and the second contact face being connected to at least one winding. In this way, the windings can be connected to one another and to the electrical connection in a reliable manner. 
     In a further embodiment of the invention, at least one of the two contact faces is in the form of an insulation displacement contact. This has the advantage that contact can be made between the feed lines of the windings and/or the line of the electrical connection by means of an insulation displacement contact in a quick and reliable manner. 
     In a further embodiment of the invention, the endshield is in the form of a plate, the first contact face being arranged on a first side of the endshield and the second contact face being arranged on a second side of the endshield. This has the advantage that the feed lines to the windings do not need to be guided through the endshield and thus the endshield can be fitted in the electric motor in a quick and reliable manner, with contact being made between the windings likewise in this process. 
     In a further embodiment of the invention, a connection to the electrical connection at the first contact face and/or the connection to the winding at the second contact face is performed by means of a welding process, a soldering process or by means of a crimping process. In this way, a connection of the components of the electric motor can be performed in a quick and reliable manner in the manufacturing process through the endshield. 
     In a further embodiment of the invention, the power supply line is in the form of a rail and/or is fastened to the endshield by means of at least one holding element. In this way, the power supply line can be fastened to the endshield in a reliable manner. 
     In a further embodiment of the invention, the endshield has at least one latching cam at the receptacle of the bearing, said latching cam being designed to fasten the bearing and/or a spring washer to the endshield. In this way, the bearing and/or a spring washer can be fixed in the receptacle in a quick and reliable manner. 
     In a further embodiment of the invention, the latching cam has, on the rear side with respect to a latching tab, a receptacle, which receives a spring ring. In this way, an additional holding force can be applied to the latching cam by means of the spring ring in order to fix the bearing and/or the spring washer. This has the advantage that the bearing and/or the spring washer are fixed in the receptacle in a particularly robust manner. 
     In a further embodiment of the invention, the endshield has, circumferentially, at least one latching element, which is designed to fix the endshield in the housing of the electric motor. In this way, the endshield can be fixed in the housing of the electric motor in a simple manner during the production process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in more detail below with reference to the figures, in which: 
         FIG. 1  shows a perspective view of a first endshield; 
         FIG. 2  shows a perspective rear view of the first endshield; 
         FIG. 3  shows a detail of a section through a housing of an electric motor with the first endshield installed; 
         FIG. 4  shows a cross section through the first endshield; 
         FIG. 5  shows a cross section through a second endshield; 
         FIG. 6  shows a cross section through a third endshield; 
         FIG. 7  shows a perspective view of a fourth endshield; 
         FIG. 8  shows a perspective view of a fifth endshield; 
         FIG. 9  shows a perspective view of a power supply line section; and 
         FIG. 10  and  FIG. 11  show a perspective view of a sixth endshield. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a perspective view of a first endshield  10  of a brushless electric motor. The electric motor comprises a rotor and a stator, which are arranged in a housing. The rotor is mounted by means of a first bearing arranged in the housing and by means of a bearing arranged in the first endshield  10 . A plurality of windings inducing an alternating magnetic field are arranged in the stator. 
     The first endshield  10  comprises a mount  11 , which is in the form of a disk. The mount  11  has, centrally, a bearing receptacle  25 , which is arranged on the mount  11 . In addition, the mount  11  comprises, circumferentially, a peripheral first web  300 . A plurality of power supply lines  13 ,  23 ,  24 ,  60  is arranged on the mount  11 . The power supply lines  13 ,  23 ,  24 ,  60  are in this case arranged in different planes partially one above the other on the mount  11 . In this case, through-openings  18  are arranged in the mount  11  in the region of the power supply lines  13 ,  23 ,  24 ,  60 . The power supply lines  13 ,  23 ,  24 ,  60  are in the form of rails and can be produced in a stamping and bending process, for example. 
     The fastening of the power supply lines  13 ,  23 ,  24 ,  60  is performed by means of the holding elements  17 ,  19 ,  20 , with first holding elements  17  having a spacer  160  and a holding tab  16 . The spacer  160  spaces apart the conductor rails  13 ,  23 ,  24 ,  60  from a surface of the mount. The spacer  160  therefore also fixes the fastening plane of the spacer  13 ,  23 ,  24 ,  60 . In order to fasten the power supply lines  13 ,  23 ,  24 ,  60  to the mount  11  in a reliable manner, the holding tabs  16  on the first holding element  17  surround the individual power supply lines  13 ,  24 ,  23 ,  60  and thus fix the position of the power supply line  13 ,  23 ,  24 ,  60 . The holding tabs  16  can in this case be bent back through approximately 90° out of a vertical position in a hot-stamping method once the power supply lines  13 ,  23 ,  24 ,  60  have been inserted, with the result that the holding tabs  16  prevent the power supply lines  13 ,  23 ,  24 ,  60  from moving after cooling. The individual power supply lines  13 ,  23 ,  24 ,  60  can be arranged on different planes owing to the different lengths of the spacer  160 , with the result that the individual conductor rails  13 ,  23 ,  24 ,  60  do not need to be insulated from one another, for example by means of an insulated surface. The distances between the individual planes of the conductor rails  13 ,  23 ,  24 ,  60  are selected such that the conductor rails  13 ,  23 ,  24 ,  60  do not come into touching contact with one another. 
     The power supply lines  13 ,  23 ,  24  each have a first contact point  12 , which is in the form of an insulation displacement contact connection. This has the advantage that the first contact point  12  can be connected permanently to a line of the electrical connection in a quick and reliable manner during fitting of the endshield  10 . 
     The power supply lines  13 ,  23 ,  24 ,  60  also have differently arranged second contact points  15 , the second contact points  15 , in the same way as the first contact points  12 , being aligned parallel to a rotor shaft axis  101  of the electric motor. The second contact points  15  are arranged in a region of the through-openings  18 . In each case individual lines  14  of the windings are guided by the mount  11  through the through-openings  18 . The lines  14  can be fastened to the second contact points  15  by means of a welding, soldering or crimping process. This has the advantage that there is a reliable connection between the lines  14  of the windings and the power supply lines  13 ,  23 ,  24 ,  26 . However, it is also conceivable for the lines  14  or the wires of the windings, in the same way as at the first contact points  12 , to be fastened to the second contact faces  15  by means of an insulation displacement region. 
     The individual power supply lines  13 ,  23 ,  24 ,  60  are configured corresponding to their function of distributing the current flow through the windings connected thereto. The windings are energized by means of a three-phase current connection, with the result that the power supply lines  13 ,  23 ,  24 ,  60  therefore have three electrical connections with the first contact points  12 . The individual windings are connected to one another by means of the first power supply lines  60 , which conduct the current from a first winding to a second winding. The second contact points  15  arranged at the first power supply lines  60  serve to connect the winding. 
     Circumferentially, a first web  300  is arranged on the mount  11 . The first web  300  has a plurality of shoulders  22 ,  220  and notches  21  in order to fix the mount  11  in a housing of the electric motor. The notches  21  serve the purpose of receiving a pinch rib (not illustrated) arranged on the housing. As the endshield  10  is pushed into the housing of the electric motor, the pinch ribs are plastically deformed by means of the notches being pushed onto the pinch ribs and, by virtue of a form-fitting connection, fix the position of the endshield  10 . An axial movement of the endshield  10  is fixed by a first shoulder  22  on the first web  300 , which prevents any further movement during fitting of the endshield  10  in the direction of the windings. A rotary movement is also prevented by a plurality of first cutouts  33  arranged on the shoulder  22  by virtue of the first cutouts  33  receiving a protrusion of the housing of the electric motor. 
       FIG. 2  shows a perspective rear view of the first endshield  10 . A bearing receptacle  25  is arranged centrally in the plate-shaped first endshield  10 . The endshield  10  has a plurality of second webs  29  in order to support the bearing forces, said second webs connecting the first web  300  to the bearing receptacle  25 . In each case through-openings  18  are arranged between the individual segments formed of the individual second webs  29 . In order to make it easier for the wires of the windings to be passed through, the through-openings  18  have a chamfered region  32 . 
     The bearing receptacle  25  has, at its inner circumferential surface, a first latching element  28  with a latching tab  44  and a latching spring  43 . The first latching element  28  is designed to hold a spring washer. This has the advantage that no additional tool is required during fitting of the endshield  10  in order to secure the spring washer, which is required for the bearing arrangement, so as to prevent it from falling out of the bearing receptacle  25 . 
       FIG. 3  shows a detail of a section through a housing  35  of the electric motor with the first endshield  10 . A hot-stamping die  34  is arranged on the first endshield  10  on the inside with respect to the first web  300 . The hot-stamping die  34  is designed to be positioned on a stamping face  39  of the first endshield  10  and to heat the stamping face  39 . The housing  35  of the electric motor has a second cutout  37 . Once the first web  300  has been heated in the region of the stamping face  39 , the hot-stamping die  34  pushes the first web  300  circumferentially outwards in the direction of the housing  35  of the electric motor. As a result, the first web  300  is pressed outwards and is matched to the contour of the second cutout  37  in the housing  35 . 
     In addition, the housing  35  has a second shoulder  220 , which is associated with the first shoulder  22 . The two shoulders  22 ,  220  serve the purpose of enabling the first endshield  10  to be inserted not too deeply into the housing  39  of the electric motor during fitting in the direction of the windings. A circumferential face  231  of the first endshield  10  serves to support the bearing forces transmitted via the second webs  29  on an inner side  230  of the housing  35 . 
       FIG. 4  shows a cross section through the first endshield  10 . In addition, a rolling bearing  400  and the spring washer  44  are arranged on the first endshield  10 . The rolling bearing  400  supports the rotor shaft  100 . The rolling bearing  400  has an inner ring  45 , which is associated with the rotor shaft  100 , and an outer ring  46 , which is associated with the bearing receptacle  25 . The bearing receptacle  25  in this case comprises a circumferentially arranged bearing face  48  and the first latching element  28 . The spring washer  44  is arranged on the left-hand side with respect to the rolling bearing  400 . The spring washer  44  bears both against the outer ring  46  and against a third shoulder  31 , which delimits the bearing face  48  in the axial direction. 
     The rotor shaft  100  is supported by means of the rolling bearing  400 . For this purpose, the rotor shaft  100  is pressed into the inner ring  45  of the rolling bearing  400 . The outer ring  46  has a sliding fit on the bearing face  48 . The bearing face  48  is provided in good time with a chamfer  47  in order to facilitate the insertion of the pressed-on rolling bearing with the rotor shaft into the endshield. The first latching element latches with the latching tab  42  on the spring washer  44  and thus ensures simple fitting of the spring washer  44  in the first endshield  10 . 
       FIG. 5  shows a cross section through a second endshield  9 . The second endshield  9  has a similar design to the first endshield  10 . However, the receiving region  25  of the bearing differs from the embodiment shown in  FIG. 1  to  FIG. 4  of the first endshield  10 . In order to fasten the rolling bearing  400  in a second mount  90  of the second endshield  9 , the second mount  90  has a multiplicity of second latching elements  51  along the bearing face  48 . On the opposite side, the bearing face  48  is delimited by the third shoulder  31 . The latching elements  51  have a second latching spring  53  and a second latching tab  54 . On that side of the latching spring  53  which is remote from the rolling bearing  400 , the latching spring  53  has a receptacle  52  for a spring ring  50 . The receptacle  52  is formed peripherally around the second latching elements  51 . The second latching tab  54  delimits the bearing face  48  and prevents the outer ring  46  of the rolling bearing  400  from being moved out of the bearing face  48 . 
     The second latching elements  51  have the advantage that the rolling bearing  400  can be introduced into the second mount  90  simply and quickly during fitting. If the rolling bearing  400  is pressed in the direction of its bearing position, the latching tabs  54  are pressed by means of the sprung suspension by virtue of the second latching springs  53  out of the movement path of the rolling bearing. If the rolling bearing is located at the stop, the outer ring  46  bears with a side face against the third shoulder  31 . A movement in the opposite direction to the fitting direction is prevented by the second latching elements  51 , which snap in again after fitting, with the second latching tabs  54 . 
       FIG. 6  shows a cross section through a third endshield  8 . In contrast to the embodiment shown in  FIG. 5 , the rolling bearing  400  is fastened on the outer ring  46  of a third mount  80  of the third endshield  8  by means of a press fit. The third endshield  8  has a sleeve  480  in the region of the bearing face  48  of the third mount  80 , said sleeve being manufactured from a metal material, for example. The sleeve  480  has been encapsulated by injection molding with the material, for example plastic, of the third mount  80  in the further production process of the third endshield  8 . The sleeve  480  serves a purpose of ensuring that the rolling bearing  400  has a reliable press fit on the outer ring  46 . The rotor shaft  100  is arranged on the inner ring  45  by means of a sliding fit. However, it is also conceivable for the rolling bearing  400  to be encapsulated by injection molding with material even during the production of the third mount  80 . Likewise, a press fit on the outer ring  46  of the rolling bearing without the sleeve  480  shown is possible. In the case of the press fit of the rolling bearing  400 , the third shoulder  31  serves a purpose of fixing the axial position during fitting of the rolling bearing  400  in the third endshield  8 . 
       FIG. 7  shows a perspective view of a fourth endshield  7 . The fourth endshield  7  has a similar design to the first endshield  10  shown in  FIG. 1  to  FIG. 4 . The fourth endshield  7  has third contact points  61 . The third contact points  61 , which replace the first contact points  12  shown in  FIG. 1 , are designed for contact to be made by means of a contact shoe. This has the advantage, in particular when making contact between lines with a relatively large cross section, of it being possible for said lines to be fastened in a reliable manner on the third contact point  61 , with a contact shoe. The rail-shaped design of the power supply lines  13 ,  23 ,  24 ,  60  also ensures a cross section which is required at high currents. 
       FIG. 8  shows a perspective view of a fifth endshield  6 . In addition to the fifth endshield  6 , a coil former  77  with a pole shoe  75  and a winding  74  is illustrated. The fifth endshield  6  has power supply lines  13 ,  24 ,  23 ,  60 ,  78  both on the side directed towards the inner side of the electric motor and on the outer side of the endshield, the power supply lines  13 ,  24 ,  23 ,  60 ,  78  being fastened to the fifth endshield  6  by means of a second holding element  76 . Two pin-shaped contact elements  73  are arranged on the pole shoe  75 . In each case one contact element  73  is connected to one end of the winding  74 . The second power supply lines  78  arranged on the inside have third contact points  72 , which protrude inwards into the housing of the electric motor and each have a contact receptacle  70 . The contact element  73  of the coil former  77  engages in the contact receptacle  70 . The second power supply lines  78  are connected to the power supply lines  13 ,  23 ,  24  located on the outer side via a power supply line element  71 . This has the advantage that the windings are automatically connected to one another by the pole shoes when the fifth endshield  6  is inserted into the electric motor by virtue of the contact points  72  engaging in the pin-shaped contact elements  73 . In this way, it is possible to avoid passing lines of the windings through the fifth endshield  6 , as shown in  FIG. 1  to  FIG. 7 , and then connecting the wires to the contact faces. In this way, the fifth endshield  6  can be built into the electric motor in a simple and quick manner, possibly also using automatic manufacturing systems. 
       FIG. 9  shows a perspective view of a power supply line section  91 . The power supply line section has three power supply lines  86 ,  87 ,  88 , which merge into a common connection  800 . The individual power supply lines  86 ,  87 ,  88  are spaced apart by power supply line holding elements  81  and fastened on a sixth endshield  5  shown in  FIG. 11  by means of the fastening elements  82  on the sixth endshield  5 . The connection  800  has a supporting element  900  laterally in order to fasten the connection  800  by means of fastening elements  82  in the sixth endshield  5  and to support the forces for pushing a jack onto the connection  800  in a reliable manner. 
       FIG. 10  and  FIG. 11  show a perspective view of the sixth endshield  5 . The sixth endshield  5  serves to receive the power supply line section  91  shown in  FIG. 10 . The fastening elements  82  of the power supply line section  91  engage in fastening openings  83  for this purpose. Contact is made between the power supply lines  92 ,  93 ,  94  by virtue of the lines of the windings being passed through the through-openings  18  and fastened on the contact faces  15 . In this way, the windings can be interconnected corresponding to the interconnection scheme. 
     It is of course familiar to a person skilled in the art that the embodiments shown of the endshields are exemplary. However, it is essential here that the endshield has, in addition to the conventional receptacle for a bearing arrangement, power supply lines which are connected to the windings and to the electrical connection. In this way, it is possible to dispense with separate interconnection of the windings via an interconnection plate. This results in a shorter fitting time for the electric motor and in a design of the electric motor which is optimized in terms of installation space.