Abstract:
The invention relates to an electrical motor ( 10 ), in particular an alternating current generator, having a housing ( 13 ) that has at least one bearing shield ( 13.2 ), having a rectifier device ( 139 ) which has an interconnection unit ( 144 ) that interconnects the current rectifier ( 147, 150 ) to a bridge circuit, characterized in that the interconnection unit ( 144 ) has at least one platform ( 295 ) that is oriented to the bearing shield ( 13.2 ) and the opening ( 40 ) is separated by at least one brace ( 340 ) which holds a hub ( 337 ), wherein the opening ( 40 ) has a niche ( 346 ) that is incorporated on the radial outer edge ( 349 ) of the opening and wherein the platform ( 295 ) projects into said niche ( 346 ) and a connection wire ( 216 ) exiting the platform ( 295 ) extends into the opening ( 40 ).

Description:
BACKGROUND OF THE INVENTION 
     EP 960464 B1 has disclosed an electrical machine in the form of an AC generator. 
     SUMMARY OF THE INVENTION 
     The proposed solution is aimed at a design of the electrical machine which is as compact as possible. By virtue of the fact that the platform extends into a recess and a connecting wire of the interconnection unit, said connecting wire emerging out of the platform, extends in the opening, it is possible for the rectifier device to move closer to the end frame, to reduce the length of the electrical machine and therefore to save a considerable amount of space. In addition, by virtue of this position of the recess and the platform with respect to one another, interface effects (flow) are reduced to the lowest possible level and, as a result, a flow cross section which is undisrupted by interfaces is as great as possible and the cooling is thus optimized. The possibility of saving space applies in particular when the connecting wire, preferably with an integrally formed loop or U-shaped terminal which is used for making contact with diode head wires, also extends, preferably exclusively, in a plane formed from the opening, i.e. in a plane which is largely determined by edges of the opening. The contact point between the connecting wire and the diode head wire should in this case also be in this plane. In order nevertheless to maintain an opening with as large an area as possible and to maintain stability of the border of said opening (fatigue failure), provision is made for a form of the platforms and a form of the recesses to be matched to one another. If the platforms fill the recesses completely or almost completely, the opening with the recess has the best possible configuration under the given circumstances, with the result that the cooling effect is the best possible. In order to improve the stability of the end frame whilst taking into consideration the cooling flow, provision is made for at least one opening to adjoin a planar end-face region, which is lower than other regions in the direction of the axis of rotation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawing: 
         FIG. 1  shows a longitudinal section through an electrical machine, 
         FIG. 2  shows a plan view of a heat sink of a cooling device of a rectifier device in accordance with a first exemplary embodiment, 
         FIG. 3  shows a view from below of the heat sink shown in  FIG. 2 , 
         FIG. 4  shows a three-dimensional view of the heat sink shown in  FIG. 2 , 
         FIG. 5   a  and 
         FIG. 5   b  each show a detail view of a variant of the heat sink shown in  FIG. 2 , 
         FIG. 6  shows a view of a further heat sink of the cooling device of the rectifier device, 
         FIG. 7  shows a further view of the heat sink shown in  FIG. 6 , 
         FIG. 8  shows a plan view of the cooling device and the rectifier device, 
         FIG. 9  shows a view from below of the cooling device and the rectifier device shown in  FIG. 8 , 
         FIG. 10  shows a three-dimensional view of the object shown in  FIG. 8 , 
         FIG. 11  shows a detail side view of the fitted rectifier device, 
         FIG. 12  shows a side view of the rectifier device, 
         FIG. 13  shows a plan view of a heat sink of a cooling device of a rectifier device in accordance with a second exemplary embodiment, 
         FIG. 14   a  and 
         FIG. 14   b  show a three-dimensional view of a further heat sink of the cooling device of a rectifier device in accordance with a second exemplary embodiment and a detail side view, 
         FIG. 15  shows a plan view of the cooling device and the rectifier device in accordance with the second exemplary embodiment, 
         FIG. 16  shows a view from below of the cooling device shown in  FIG. 15 , 
         FIG. 17   a  and 
         FIG. 17   b  show a side view and a plan view of a guide connecting piece in accordance with the two exemplary embodiments, 
         FIG. 18  shows a basic sectional view through the layer structure in accordance with the two exemplary embodiments, 
         FIG. 19  shows a side view of the rectifier device in accordance with the second exemplary embodiment, 
         FIG. 20  shows a three-dimensional view of an end frame, 
         FIG. 21  shows a sectional illustration through a platform in accordance with the two exemplary embodiments, 
         FIG. 22  shows a stator in a side view. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a cross section through an electrical machine  10 , in this case in the form of a generator or an AC generator, in particular, an alternator for motor vehicles. This electrical machine  10  has, inter alia, a two-part housing  13 , which comprises a first end frame  13 . 1  and a second end frame  13 . 2 . The end frame  13 . 1  and the end frame  13 . 2  accommodate a so-called stator  16 , which firstly comprises a stator core  17  substantially in the form of a circular ring and has a stator winding  18  inserted into the slots of said stator, said slots being directed radially inwards and extending axially. This annular stator  16  surrounds, with its slotted surface which points radially inwards, a rotor  20  in the form of a claw-pole rotor. The rotor  20  comprises, inter alia, two claw-pole plates  22  and  23 , with in each case claw-pole fingers  24  and  25  extending in the axial direction being arranged on the outer circumference of said claw-pole plates. In this case, the axial direction is determined by an axis of rotation  26  of the rotor  20 . Both claw-pole plates  22  and  23  are arranged in the rotor  20  in such a way that the claw-pole fingers  24  and  25  thereof, extending in the axial direction, alternate with one another over the circumference of the rotor  20 . This results in magnetically required interspaces between the oppositely magnetized claw-pole fingers  24  and  25 , which are referred to as claw-pole interspaces. The rotor  20  is mounted rotatably in the respective end frames  13 . 1  and  13 . 2  by means of a shaft  27  and in each case one roller bearing  28  located on each rotor side. 
     The rotor  20  has in total two axial end faces, on which in each case one fan  30  is fastened. This fan  30  substantially comprises a plate-shaped or disk-shaped section, from which fan blades emanate in a known manner. These fans  30  serve the purpose of providing the possibility of air exchange between the outside of the electrical machine  10  and the interior of the electrical machine  10  via openings  40  in the end frames  13 . 1  and  13 . 2 . For this purpose, the openings  40  are provided substantially at the axial ends of the end frames  13 . 1  and  13 . 2 , via which cooling air  41  is sucked in by means of the fans  30  as coolant into the interior of the electrical machine  10 . This cooling air is accelerated radially outward by the rotation of the fans  30 , with the result that it can pass through the winding overhang  45  through which cooling air can pass. Owing to this effect, the winding overhang  45  is cooled. Once it has passed through the winding overhang  45  or once it has flowed over this winding overhang  45 , the cooling air takes a path radially outwards, through openings not illustrated here in this  FIG. 1 . 
     On the right-hand side in  FIG. 1  there is a protective cap  47 , which protects various components from environmental influences. For example, this protective cap  47  covers a so-called slipring assembly  49 , which serves the purpose of supplying field current to a field winding  51 . Arranged around this slipring assembly  49  is a first heat sink  53 , which in this case acts as a positive heat sink. A further heat sink, which is not shown in this variously schematic figure, acts as a so-called negative heat sink. A connecting plate  56  is arranged between the end frame  13 . 2  and the heat sink  53  and serves the purpose of connecting the negative diodes  58  arranged in the negative heat sink and the positive diodes (not shown in this illustration here) in the heat sink  53  to one another and therefore representing a bridge circuit known per se. 
       FIG. 2  depicts a first heat sink  53 . This heat sink  53  has an arcuate heat sink region  60 . This arcuate heat sink region  60  has a central mid-point  63 . In the state in which it is fitted to the housing  13 . 2 , this central mid-point is congruent with the axis of rotation  26 . The heat sink  53  has three receptacles  66 , which are each used for accommodating a current rectifier. The current rectifier is in this case a positive diode, for example. The receptacles  66  in this case have the form of a hole, into which so-called press-in diodes (positive diodes) are later pressed, for example. Alternatively, a depression can also be provided in the surface of the first heat sink  53 , for example, in order to fix a diode in the depression by means of soldering. It is also possible for a diode to be soldered to an intended location in the plane, instead of in a depression. Furthermore, the heat sink  53  has several openings, which serve to allow coolant to flow through the heat sink  53  which is hot during operation. First openings  69  are arranged next to one another in an arcuate row around a receptacle  66 . These first openings  69  are arranged on both sides of a receptacle  66 , i.e. on the right and left when viewed from the mid-point  63 , for example, in the circumferential direction U. At least one elongate second opening  72  is arranged between the receptacles  66  and the central mid-point  63  in the direction towards the central mid-point  63 , the second opening  72  with its elongate form being aligned at least substantially with the central mid-point  63 . As further detail, it can also be stated that a plurality of elongate second openings  72  are arranged between the receptacles  66  with the first openings  69  and the central mid-point  63  in the direction towards the central mid-point  63 , with the second openings  72  with their elongate form being aligned at least substantially with the central mid-point  63 . Elongate means that the openings  72  have a longer extent in the radial direction than in the circumferential direction. 
     Furthermore, three cylindrical countersink regions  75 , each provided with a hole  74 , are provided in the heat sink region  60 . There, the material thickness of the heat sink  53  is reduced to approximately 40% of that which is provided in the receptacles  66 . These countersink regions are used during fitting for fixing the rectifier device to the outer side of the end frame  13 . 2 . A threaded sleeve  78  serves to fix and to produce contact with a further component of the rectifier device. An insertion dome  82  is used for subsequently receiving and fixing a so-called B+ bolt (B-plus bolt), to which a charging cable is fixed in order to be able to supply electrical current to a vehicle battery. 
     As has already been mentioned, preferably a plurality of receptacles  66  is provided which are arranged spaced apart from one another on the circumference  81 , i.e. preferably on or in the region of the outer circumference, of the heat sink  53 . On the outer circumference primarily means in the radially outer half 
       FIG. 2  shows that a preferably integrally formed overhang  92  of the heat sink  53  is arranged in a segment  84  between two receptacles  66 , said overhang in this case in the example being designed to have a plurality of elongate second openings  72 , which extend between two crosspieces  87  with an arcuate extent. The overhang  92  is separated or spaced apart from the receptacles  66  and the first openings  69  therein, on both sides in the circumferential direction U, by large bay-shaped cutouts  94 . A radially inner end of the bay-shaped cutouts  94  is less far removed from the central mid-point  63  than a center  113  of a receptacle  66 . The second openings  72  between two arcuate crosspieces  87  are separated by webs  90 . The webs  90  preferably extend radially. The two crosspieces  87  run at least approximately in the form of a circular arc. 
     In the segment  84  between two receptacles  66 , a conductor-like cooling segment  93 , as an exemplary embodiment of an overhang  92 , which is integrally connected to one crosspiece  87 , extends from the outer of the two just-mentioned crosspieces  87  radially outwards. This conductor-like cooling segment  93  likewise has elongate cooling air openings  96 , which are separated from one another by webs  99 . These cooling air openings  96  are delimited radially outwards by a crosspiece  102 . In the circumferential direction U, the cooling segment  93  has at least one opening  108  towards the lateral edge  105  of said cooling segment, the border  111  of said opening partially having a smaller material thickness than other openings  96  in the conductor-like cooling segment  93 . In particular, provision is made for that lateral part of the border  111  which delimits a cutout  94  and possibly the radially outer of the lateral openings  108  to have a smaller material thickness. 
     A cooling segment  93 , which is configured analogously to the just-described cooling segment  93 , is likewise provided between the receptacles  66  approximately at the one o&#39;clock and the four o&#39;clock positions ( FIG. 2 ). 
     The openings  69  are arranged around the receptacles  66 . In order to improve access to connecting contacts, subsequently shown, which are positioned in the rectifier device next to the openings  69 , provision is made for borders  112  of the openings  69  to have a smaller material thickness in the axial direction (axis of rotation  26 ) or in the direction of a profile axis  115  than is the case between the receptacles  66  and the openings  69  on the side of the opening  69  which are remote from a center  113  of a receptacle  66 . For the same reason, the lateral openings  108  have a smaller material thickness. The profile axis  115  extends along the profile or passage profile of an opening  69 . 
     Further elongate openings  72  adjoin the two outer crosspieces  87  radially inwards in another row and radially inwards, delimited by a further crosspiece  86  radially inwards. 
     The receptacle  66 , the first openings  69  and the at least one elongate second opening  72  are located in a sector  116  starting from the central mid-point  63 , the sector  116  having an angular width of between 25° and 40° (all exemplary embodiments). 
       FIG. 3  shows the rear side of the heat sink  53 , which is not shown in  FIG. 2 . Regions of both sides are substantially parallel to one another. Subsequently, a B+ bolt with its round head is plugged through into a depression  114  in such a way that the round head finds its position in the depression  114  and a screw thread is visible from the side shown in  FIG. 2 . 
       FIG. 4  shows a heat sink  53  in a three-dimensional view from the side illustrated in  FIG. 2 . Here, the overhangs  92  or conductor-like cooling segments  93  are shown clearly. This applies particularly to the openings  108  and the lateral edge  105  thereof, the border  111  of said edge partially having a smaller material thickness than other openings  96  in the overhang  92  or the conductor-like cooling segment  93 . 
       FIGS. 5   a  and  5   b  show various details and therefore also alternatives to fastening with a B+ bolt. In  FIG. 5   a , an alternative or additional insertion dome  82  is provided in comparison with the illustration in  FIG. 2  next to the countersink region  75  located at the “9 o-clock” position, with it being possible for an additional or alternative B+ bolt to be inserted into said insertion dome. In  FIG. 5   b , an insertion dome  82  is provided in bent-back form. A B+ bolt can be inserted into the insertion dome  82  from the right on the lower side of the heat sink  53 . 
       FIG. 6  depicts a further heat sink  117 . The heat sink  117  has three receptacles  120 , which serve the purpose of receiving in each case one current rectifier. The current rectifier is in this case a negative diode, for example. The receptacles  120  in this case have the form of a hole, into which so-called press-in diodes (negative diodes) are later pressed, for example. Alternatively, a depression can also be provided in the surface of the further heat sink  117 . Furthermore, the heat sink  120  has several openings  123 , which serve to allow coolant to flow through the heat sink  120 , which is hot during operation. 
     In this case, too, a preferably integrally formed overhang  127  in the form of a conductor-like cooling segment  129  is located at at least one circumferential point  126 . This conductor-like cooling segment  129  has openings  132 , which extend longitudinally and radially outwards. The cooling segment  129  extends over a defined circumferential region in each case between two receptacles  120 . The heat sink  117  is beveled on the inner circumference  135  (bevel  138 ). As can be seen in  FIG. 7 , that surface  138  which later points towards the first heat sink  53  is substantially planar. An outer contour  128  of the further heat sink  117  has in each case one bay-shaped cutout  130  on both sides of the overhang  127 , for example directly adjacent to said overhang. In turn, these bay-shaped cutouts  130 , when viewed in the circumferential direction, are each located between the overhang  127  and a respective further cutout  131 . In the direction of the provided axis of rotation  26 , it can furthermore be seen that the overhang  127 , the cutout  130  and the cutout  131  are each located on an identical radius with respect to the axis of rotation  26 . 
     In the assembly of the cooling device, provision is made for the two heat sinks  53  and  117  to be layered one on top of the other at a distance from one another in such a way that a flow can pass through and between them, and the conductor-like cooling segment  129  of the further heat sink  117  is arranged above the conductor-like cooling segment  93  of the first heat sink  53 . Accordingly, the invention discloses a cooling device  141 , said cooling device having a heat sink  117 , which has further holes  123  and is substantially in the form of a ring segment, a conductor-like cooling segment  129  being located at at least one circumferential point  126 , the two heat sinks  53 ,  117  being layered one on top of the other at a distance from one another in such a way that a flow can pass through and between them, and the conductor-like cooling segment  129  of the further heat sink  117  is arranged above the conductor-like cooling segment  93  of the first heat sink  53 . 
       FIG. 8  shows the cooling device  141  which is assembled to form the rectifier device  139  and comprises a first heat sink  53  (positive heat sink), a second heat sink  117  (negative heat sink), the interconnection unit  144 , positive current rectifiers  147  (positive diodes), negative current rectifiers  150  (negative diodes), B+ bolts  153 , insulating sleeves  156  and rivets  159  (tubular rivets). Furthermore, spacers are used (not shown here). The view of the cooling device  141  corresponds to the view from the right in direction of the axis of rotation  26  in respect of  FIG. 1  with the protective cap  47  removed. 
     The interconnection unit  144  has, in a known manner, a plurality of conductor sections  162 ,  165  and  168  which serve the purpose of interconnecting in each case one pair  171 ,  174  and  177  of in each case one positive current rectifier  147  (positive diode) and in each case one negative current rectifier  150  such that the stator windings which are connected to the connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195  (via the circumferential arc  198 ) and the AC voltage produced thereby is rectified. The connecting contacts  180  and  183  are connected to the pair  171 , the connecting contacts  186  and  189  are connected to the pair  174  and the connecting contacts  192  and  195  are connected to the pair  177  (via the circumferential arc  198 ). 
       FIG. 9  shows the assembled cooling device  141  from the other side, namely the side not shown in  FIG. 8 . From this side, connecting contacts  201  and  204 , connecting contacts  207  and  210  and connecting contacts  213  and  216  are shown, which each interconnect a pair  171 ,  174  and  177  of in each case one positive current rectifier  147  (positive diode) and in each case one negative current rectifier  150 . This interconnection corresponds to a conventional bridge rectifier circuit. The positive current rectifiers  147  (positive diodes), press-in diodes and the negative current rectifiers  150  (negative diodes), are electrically conductively connected to the first heat sink  53 , with the result that during operation (in the switched-on state, field current, rotating rotor  20 ), a positive voltage is applied to the B+ bolt  153  via the current rectifier  150 . 
     The heat sink  117  having holes  123  is substantially in the form of a ring segment, wherein an overhang  127  or conductor-like cooling segment  129  is located at at least one circumferential point  126 , the two heat sinks  53  and  117  being layered one on top of the other at a distance from one another in such a way that a flow can pass through and between them, and the conductor-like cooling segment  129  of the further heat sink  117  is arranged above the conductor-like cooling segment  93  of the first heat sink  53 . A greatest outer diameter of the overhang  127  or cooling segment  129  is smaller than an outer diameter of the overhang  92  of the cooling segment  93 . The circumferential arc  198  is located, with respect to the axis of rotation  26 , at the same axial position as an outer edge  219  and, with respect to  FIG. 9 , over the overhang  92 . As can be seen from  FIG. 9 , the circumferential arc  198  of the conductor section  168  has a plurality of bends  222 . Some of these bends  222  are at an identical circumferential position to that of the connecting contacts  201 ,  207  and  213 . The bends  222  result in a distance (not denoted any further here) between a bend  222  and a connecting contact  201 ,  207  and  213  being greater than when a simple circular arc is provided at the position of the bend  222 . A bend angle determined at the bend  222  is thus arranged such that the bend angle is located on the radial inner side of the circumferential arc. The outer angle complementary to the bend angle is greater than the bend angle. The circumferential arc  198  extends, with respect to the mid-point (axis of rotation  26 ), over an angular dimension that is greater than the angle over which the current rectifiers  147  and  150  together extend in the heat sink  53  and  117 . In other words, the circumferential arc  198  extends over approximately 225° of the circumference, with respect to the mid-point (axis of rotation  26 ). The circumferential arc  198  is supported on the guide connecting piece  225  by means of integrally formed eyelets  223 . In a side view, the rectifier device  139  can be described as follows: 
     an overhang  92  has initially one cutout  94  on the right and the left in the circumferential direction U, with a guide connecting piece  225  resting in said cutout. Initially a cutout  130 , in which a guide connecting piece  225  rests, is located next to an overhang  127  on the right and left in the circumferential direction U. Starting from the overhang  127 , a further cutout  131 , into which connecting contacts  239  (diode head wires) protrude, is located on the other side of the cutout  130 . 
     The interconnection unit  144  has guide connecting pieces  225  at in total six positions, in the example shown in  FIGS. 8 and 9 . These guide connecting pieces  225  have the task of receiving, with their funnel-shaped ends directed towards the viewer in  FIG. 9 , some conductor ends of the stator winding  18  and of guiding said conductor ends in a targeted manner to (U-shaped or loop-shaped) connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195 , which emerge out of the guide connecting pieces and extend at an angle over said guide connecting pieces, in order that it is easily possible for contact to be made between the conductor ends and the connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195 , preferably by machine. Four of the tubular guide connecting pieces  225  and in each case one connecting contact  183 ,  186 ,  189  and  192  of the interconnection unit  144  are located between a conductor-like cooling segment  93  and a receptacle  66 . The two other guide connecting pieces  225 , at the “4 o&#39;clock” and approximately “5 o&#39;clock” positions in  FIG. 8 , are outside the outer contour of the first heat sink  53 . The guide connecting piece  225  which is located between the end frame  13 . 2  and the controller  231  in the direction of the axis of rotation  26 , is arranged outside the outer contour of the first heat sink  53 , when viewed in the direction of the axis of rotation  26 . 
     While the guide connecting piece  225  at the “4 o&#39;clock” position is configured in terms of its size and configuration substantially like the other four guide connecting pieces  225 , the guide connecting piece  225  at the “5 o&#39;clock” position is different. Said guide connecting piece  225 , which is referred to below as the “small” guide connecting piece  225 , does also have a connecting contact  195 . However, the guide connecting piece  225  itself is a small guide connecting piece  225  and is therefore shorter than the other guide connecting pieces  225  with respect to the axis of rotation  26  (see also  FIG. 10 ). The guide connecting pieces  225  are integrally connected to one another by webs  226 . The conductor section  162  is located in the web  226  between the guide connecting piece  225  at the “2 o&#39;clock” position ( FIG. 9 ) and the guide connecting piece  225  at the “4 o&#39;clock” position. There is no conductor section embedded in the web  226  between the “4 o&#39;clock” position and the “6 o&#39;clock” position, but in turn, there is one located in the web  226  between the “6 o&#39;clock” position and the “7 o&#39;clock” position. A further conductor section  162  is embedded between the guide connecting piece  225  at the “9 o&#39;clock” position and that end  227  of the interconnection unit  144  which then merges with the circumferential arc  198  of the conductor section  168  and leads to the small guide connecting piece  225 . The conductor sections, with the exception of the circumferential arc  198 , are each embedded in the polymer material of the interconnection unit  144 . 
     The interconnection unit  144  is to a large extent located in a region around which there is little or no flow of cooling air (flow dead-area). This region is in the radially outer region (axis of rotation  26 ) below the first heat sink  53  (positive heat sink). In any case, this applies to the webs  226  and the circumferential arc  198 , which are both arranged, in respect of the radial extent of the first heat sink  53  (positive heat sink) beneath an outer half of the radial extent thereof “Beneath” an outer half means that the webs  226  and the circumferential arc  198  are located between the end frame and the heat sink  53  (positive heat sink). Furthermore, the circumferential arc  198  and a radially outer edge of the receptacles  66  are preferably congruent (see also  FIG. 9 ). 
     The purpose of this arrangement is shown in  FIG. 11 : as is the case for all of the other guide connecting pieces  225 , the small guide connecting piece  225  is also arranged or plugged into an opening  228  in the end frame  13 . 2 . Conductor ends  228  of the stator winding  18  are plugged in through the small guide connecting piece  225  and are electrically conductively connected at their upper end to the connecting contact  195 . A welded joint or else a soldered joint is preferably provided at this point. It is likewise also possible in an alternative configuration for a screw connection to be provided here. By virtue of this small guide connecting piece  225  being designed to be so short, it is possible for said small guide connecting piece to be arranged between the stator winding  18  and a controller  231  in a space-saving manner in the axial direction (axis of rotation  26 ). The controller  231  serves the purpose of generating a field current and, by means of brushes (not illustrated here), supplying field current to the field winding  51  via the abovementioned slipring assembly  49  and thereby electromagnetically exciting the rotor  20 . An arm  234 , in which the conductor section  168  is embedded and which physically connects the two guide connecting pieces  225  to one another, said guide connecting pieces being located outside the outer contour of the first heat sink  53 , likewise reaches beneath the controller  231  and therefore into an interspace  237 , which is located between a lower side  240  of the controller  231 , said lower side being directed in the axial direction (axis of direction  26 ) towards the end frame  13 . 2 , and the end frame  13 . 2  itself. The arm  234 , which integrally connects the short guide connecting piece  225  to the other guide connecting pieces  225 , in the process engages around a fixing connecting piece  238  radially from the inside ( FIG. 20 ). 
     The invention therefore discloses an electrical machine  10 , in particular an AC generator, with a rotor  20 , which has an axis of rotation  26 , with a stator  16  comprising a stator core  17  and a stator winding  18  inserted therein which has conductor ends  228 , which are interconnected by a rectifier device  139 , with a controller  231  for controlling a field current and a cooling device in the rectifier device  139 , with a first heat sink  53 , which has at least one receptacle  66  at which a current rectifier  147  is received, with a second heat sink  117 , the heat sink  117  having at least one receptacle  120  at which a current rectifier  150  is received, with an interconnection unit  144 , which interconnects the current rectifiers  147 ,  150  to form a bridge circuit, wherein the interconnection unit  144  has a plurality of integrally formed guide connecting pieces  225 , in which conductor ends  228  of the stator winding  18  are received, a guide connecting piece  225  being arranged between the end frame  13 . 2  and the controller  231  in the direction of the axis of rotation  26 . 
       FIG. 12  shows a side view of the cooling device  141 . Spacers  246  between the first heat sink  53  and the further heat sink  117  ensure a distance A between the two heat sinks  53  and  117 . The guide connecting pieces  225  are plugged into the openings  228  in the end frame  13 . 2 , with the result that the webs  226  rest on the end frame  13 . 2 . The heat sink  117  is arranged with part of its body between in each case two directly adjacent guide connecting pieces  225 ; furthermore, part of the heat sink  117  is surrounded by the webs  226 .  FIG. 12  shows a few connecting contacts  239  (diode head wires) of the current rectifiers  147  and  150 . 
       FIG. 13  depicts a further exemplary embodiment of a first heat sink  53 . This heat sink  53  has an arcuate heat sink region  60 . This arcuate heat sink region  60  has a central mid-point  63 . This central mid-point  63  is congruent with the axis of rotation  26  in the state in which the heat sink is fitted to the housing  13 . 2 . The heat sink  53  has three receptacles  66 , which serve the purpose of receiving in each case one current rectifier. The current rectifier is in this case a positive diode, for example. In this case, the receptacles  66  have the configuration of a hole, into which so-called press-in diodes (positive diodes) are later pressed in, for example. Instead of a hole, it is alternatively also possible, for example, for a depression to be provided in the surface of the first heat sink  53  in order to fix the diode; cf. also the description relating to the previously-mentioned exemplary embodiment. Furthermore, the heat sink  53  has several openings, which are used for allowing a flow of coolant to pass through the heat sink  53  which is hot during operation. First openings  69  arranged next to one another in an arcuate row are arranged around a receptacle  66 . These first openings  69  are arranged on both sides of a receptacle  66  in the circumferential direction U. In the direction towards the central mid-point  63 , at least one elongate second opening  72  is arranged between the receptacles  66  and the central mid-point  63 , the second opening  72  with its elongate form being aligned at least substantially with the central mid-point  63 . On closer look, it can also be seen that a plurality of elongate second openings  72  are arranged between the receptacles  66  with the first openings  69  and the central mid-point  63  in the direction towards the central mid-point  63 , the second openings  72  with their elongate form being aligned at least substantially with the central mid-point  63 . Two openings  229 , that is to say in the second row around the respective receptacle  66 , are used for fixing the heat sink  53  to the interconnection unit  144 , by virtue of an optional, preferably clamping, pin (press-fit between pin and opening  229 ) or snap-action hook of the interconnection unit  144  engaging in the respective opening  229 . 
     Furthermore, three cylindrical countersink regions  75  provided in each case with a hole  74  are provided in the heat sink region  60 . There, the material thickness of the heat sink  53  is reduced to approximately 40% of that which is provided for the receptacles  66 . These countersink regions  75  serve during fitting for fixing the rectifier device  139  to the end frame  13 . 2 . A threaded sleeve  78  is used for fixing and making contact with a further component of the rectifier device  139  and is integrally formed on the heat sink  53 , as is already the case in the first exemplary embodiment. An insertion dome  82  is used for subsequently receiving an fixing a so-called B+ bolt (B-plus bolt) on which a charging cable is fixed in order to be able to supply electrical current to a vehicle battery. 
     As has already been mentioned, a plurality of receptacles  66  is provided which are arranged spaced apart from one another on the circumference  81  of the heat sink  53 . 
     It can be seen from  FIG. 13  that a plurality of elongate second openings  72  are arranged in a segment  84  between two receptacles  66 , said openings extending between two crosspieces  87  with an arcuate extent. The second openings  72  between the two arcuate crosspieces  87  are separated by webs  90 . The webs  90  preferably extend radially. The two crosspieces  87  run at least approximately in the form of a circular arc. 
     The openings  69  are arranged around the receptacles  66 . In order to improve access to subsequently shown connecting contacts which are positioned in the rectifier device  139  next to the openings  69 , provision is made for borders  112  of the openings  69  to have a smaller material thickness in the axial direction (axis of rotation  26 ) on the side of the openings  69  which are remote from a center  113  of a receptacle  66  than is the case between the receptacles  66  and the openings  69 . 
     By way of example, eight hook elements  235  are located over the outer circumference  232  of the heat sink  53 . In each case two hook elements  235  arranged in pairs are positioned opposite one another such that said two hook elements, together with the outer circumference  232 , form an undercut, which will be described in more detail further below. 
       FIG. 14   a  shows a three-dimensional view of a further heat sink  117  of the second exemplary embodiment. The heat sink  117  has three receptacles  120 , which serve the purpose of receiving in each case one current rectifier. The current rectifier is in this case a negative diode, for example. Here, the receptacles  120  have the form of a hole, into which so-called press-in diodes (negative diodes) are later pressed in, for example. Alternatively, a depression can also be provided in the surface of the further heat sink  120 , for example; see also the explanations previously as regards various fixing possibilities for diodes. Furthermore, the heat sink  120  has several openings  123 , which are used for allowing a flow of coolant to pass through the heat sink  120  which is hot during operation. Furthermore, three cylindrical depressions  238  are introduced in the surface of the heat sink  117  and serve the purpose of centering cylindrical spacers. Various ribs are illustrated at the outer circumference  241  of the heat sink  117 . The ribs  244  and  247  are directly adjacent ribs which can also be referred to as very flat cooling ribs of the laminated heat sink  117 , which is 4 mm thick, for example. A stepped recess  250  is located between these two ribs  244  and  247 . This stepped recess  250  comprises a small sub-recess  253 , which is closer to a center (not illustrated here) of the heat sink  117  than a larger outer recess  256 , which opens radially further outwards and is also part of the recess  250 . Such a stepped recess  250  is provided on the outer circumference  241  in total two times. A further special recess  256 , likewise delimited by ribs  259  and  262 , is likewise located on the outer circumference  241 . Round holes  265  are likewise shown, by way of example, four times over the outer circumference  241  of the heat sink  117  and therefore directly above the webs of an interconnection means (not yet shown in this example), said holes being countersunk on the side on which the depressions  238  are located. Ribs  268  are arranged distributed over the inner circumference of the heat sink  117 . 
     A view of a depression  238  can be seen in  FIG. 14   b , which shows a view of the ribs  268 . The depression  238  is opposite a platform  271  which has a slightly larger diameter. 
       FIG. 15  shows a plan view of the rectifier device  139  or assembled cooling device  141  comprising the first heat sink  53  (positive heat sink), the second heat sink  117  (negative heat sink), the interconnection unit  144 , the positive current rectifiers  147  (positive diodes), the negative current rectifiers  150  (negative diodes), the B+ bolts  153 , the insulating sleeves  156  and the rivets  159  (tubular rivets). Furthermore, spacers (not shown here) are used. The view of the cooling device  141  corresponds to the view from the right in direction of the axis of rotation  26  of  FIG. 1  with the protective cap  47  removed. 
     The interconnection unit  144  has, in a known manner, a plurality of conductor sections  162 ,  165  and  168 , which serve the purpose of interconnecting in each case one pair  171 ,  174  and  177  of in each case one positive current rectifier  147  (positive diode) and in each case one negative current rectifier  150  in such a way that the stator windings connected to the connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195  (connecting arc) and the AC voltage produced thereby is rectified. The connecting contacts  180  and  183  are connected to the pair  171 , the connecting contacts  186  and  189  are connected to the pair  174  and the connecting contacts  192  and  195  (via the circumferential arc  198 ) are connected to the pair  177 . 
       FIG. 15  also shows that, as is already the case in the first exemplary embodiment, the elongate openings  72  are arranged axially (axis of rotation  26 ) above the negative current rectifiers  150  (negative diodes). The negative current rectifiers  150  (negative diodes) are in this case also, in relation to the axis of rotation  26  as the center, on a smaller radius than the positive current rectifiers  147  (positive diodes). That part of the heat sink  53  which is delimited by the inner of the two crosspieces  87  is arranged on a larger radius than that region of the heat sink  117  which is arranged at this circumferential point. 
     The rectifier arrangement is connected to the stator windings at the connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195  (connecting arc). For this purpose, as shown in  FIG. 11 , provision is made for conductor ends  228  (stator connecting wires) to be pushed through the guide connecting pieces  225  and the loop-shaped connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195 . The actual fixing and contact-making between the connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195  and the conductor ends  228  is performed by virtue of the connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and thus the lateral wire regions (see example and contact point C) of the conductor section  165  being pressed above the guide connecting piece  225  in the direction of the arrows illustrated there and being welded to one another once contact has been made with the conductor ends  228 . Alternatively, contact-making by means of soldering is also possible here, for example. In order that the lateral wire regions of the conductor section  165  can be moved towards one another at all, a correspondingly shaped (welding) tongue is required, for example. The tongue parts thereof need to be introduced between a lateral wire region of a connecting contact and the borders  112  of the openings  69  on the side of the openings  69  which are remote from a center  113  of a receptacle  66 . This makes it possible for the material thickness of the border  112  to be smaller in the axial direction (axis of rotation  26 ) than is the case between the receptacles  66  and the openings  69 . The heat sink  53  is less thick there.  FIG. 15  shows the pins  274  which have already been mentioned with respect to  FIG. 13 , showing the way in which said pins protrude through the opening  229  and connect the heat sink  53  to the interconnection unit  144  in clamping fashion in the opening  229 . A conductor in the form of a circumferential arc  198  emanates integrally from a connecting contact  195  which is directly associated with the short guide connecting piece  225 , a section of said conductor being arranged beneath an outer edge of a receptacle  66 , in the direction of the axis of rotation  26 . The circumferential arc  198  is arranged between the end frame  13 . 2  and the heat sink  53 . 
     A screw-on connecting piece  275  bears a contact loop  276 , which covers beneath it a screw nut  278  which is encapsulated by injection molding and is embedded in the polymer of the screw-on connecting piece. The contact loop  276  acts as a so-called “V terminal”. The screw-on connecting piece  275  has the same design in all of the exemplary embodiments. 
       FIG. 16  shows the assembled cooling device  141  from the other side, namely the side not shown in  FIG. 15 . From this side, connecting contacts  201  and  204 , connecting contacts  207  and  210  and connecting contacts  213  and  216  can be seen, which each interconnect a pair  171 ,  174  and  177  of in each case one positive current rectifier  147  (positive diode) and in each case one negative current rectifier  150 . This interconnection corresponds to a conventional bridge rectifier circuit. The positive current rectifiers  147  (positive diodes), press-in diodes and also the negative current rectifiers  150  (negative diodes) are electrically conductively connected to the first heat sink  53  with the result that, during operation (in the switched-on state, field current, rotating rotor  20 ) a positive voltage is present at the B+ bolt  153  via the current rectifier  150 . 
     The heat sink  117  having holes  123  is substantially in the form of a ring segment, the two heat sinks  53  and  117  being layered one on top of the other at a distance from one another in such a way that a flow can pass through and between them. As can also be seen from  FIG. 9 , the circumferential arc  198  of the conductor section  168  has a plurality of bends  222 . Some of these bends  222  are at an identical circumferential position to the connecting contacts  201 ,  207  and  213 . The bends  222  result in a distance (not described in any further detail here) between a bend  222  and a connecting contact  201 ,  207  and  213  which is greater than if a simple circular arc were to be provided at the position of the bend  222 . This improves the accessibility to the connecting contacts  201 ,  207  and  213 , for example, which need to be connected to the connecting contacts of the current rectifiers  147  (diode head wires). 
     The interconnection unit  144  has guide connecting pieces  225  at in total six positions, in the example shown in  FIGS. 15 and 16 . These guide connecting pieces  225  have the task, as already mentioned, of receiving some conductor ends of the stator winding  18  with their funnel-shaped ends directed towards the viewer in  FIG. 16  and of guiding said conductor ends in a targeted manner to the connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195 , in order that it is easily possible for contact to be made between the conductor ends and the connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195 , preferably by machine. While the guide connecting piece  225  at the “7 o&#39;clock” position has substantially the same configuration in terms of its size and configuration as the other four guide connecting pieces  225  (“9 o&#39;clock”, “10 o&#39;clock”, “12 o&#39;clock” and “2 o&#39;clock” positions, position indications with reference to  FIG. 16 ), the guide connecting piece  225  at the “6 o&#39;clock” position is different. This guide connecting piece  225 , which is referred to below as the “small” guide connecting piece  225 , does also have a connecting contact  195 . However, the guide connecting piece  225  itself is a small guide connecting piece  225  and is therefore shorter than the other guide connecting pieces  225  in respect of the axis of rotation  26  (see also  FIG. 10 ). The guide connecting piece  225  between the end frame  13 . 2  and the controller  231  is shorter than the other guide connecting pieces  225  in the direction of the conductor ends  228  arranged in the guide connecting piece  225 . The guide connecting pieces  225  are integrally connected to one another by webs  226 . The conductor section  162  is located in the web  226  between the guide connecting piece  225  at the “6 o&#39;clock” position and the guide connecting piece  225  at the “7 o&#39;clock” position. There is no conductor section embedded in the web  226  between the “12 o&#39;clock” position and the “2 o&#39;clock” position but in turn there is one in the web  226  between the “12 o&#39;clock” position and the “10 o&#39;clock” position. A further conductor section  162  is embedded between the guide connecting piece  225  at the “2 o&#39;clock” position and that end  227  of the interconnection unit  144  which then merges with the circumferential arc  198  of the conductor section  168  and is guided over the circumference towards the “small” guide connecting piece  225 .  FIG. 16  shows the connecting contacts  239  (diode head wires) of the current rectifiers  147  and  150 . 
     In  FIG. 15 , the significance of the abovementioned hook elements  235  becomes clear: the eight hook elements  235  located at the outer circumference  232  of the heat sink  53  lead to a clear positional assignment between the heat sink  53  and the received current rectifiers  147 . This provides the possibility of reliably precise positioning of the connecting contacts  239  (diode head wires) of the positive current rectifiers  147  with respect to the connecting contacts  201 ,  207  and  213  of the interconnection unit  144 . In each case two hook elements  235  arranged in pairs are positioned opposite one another such that the two hook elements together with the outer circumference  232  form an undercut. Two mutually opposite hook elements  235  engage behind two undercuts  277 , which are integrally formed on the guide connecting piece  225  and, in the plan view shown in  FIG. 15 , are located on each of the two sides of a connecting contact  183 ,  186 ,  189 ,  192  and  195 . With respect to the axis of rotation  26  the undercuts  277  are at least partially at the same axial position as the guide connecting pieces  225 . 
     At least part of the guide connecting pieces  225  or the next respective environment thereof has other functions in addition to the task of holding the connecting contacts  180 ,  183 ,  186 ,  189 ,  192  and  195 . Thus, firstly the heat sink  117  needs to be centered with respect to the interconnection unit  144  and held or gripped in the circumferential direction in the correct position. Furthermore, a correct position of the heat sink  117  with respect to the interconnection unit  144  needs to be ensured in the axial direction (axis of rotation  26 ). This makes it possible, firstly, for the current rectifiers  150  (negative diodes) already located in the receptacles  66  in this fitting step to be brought into the correct position, i.e. to supply the connecting contacts  204 ,  210  and  216  of the interconnection unit  144  in the correct position. This is achieved by virtue of the fact that a centering shoulder  280  is integrally formed on the guide connecting pieces  225  on a radial inner side of the guide connecting pieces  225  (see also  FIGS. 17   a  and  17   b ). When the heat sink  117  is fitted onto the interconnection unit  144 , this centering shoulder  280  or centering stub protrudes into the stepped recess  250  and very particularly into the small sub-recess  253  (see also  FIG. 16 ). This centering takes effect before the connecting contacts  239  (diode head wires) of the current rectifiers  150  (negative diodes) are supplied into the connecting contacts  204 ,  210  and  216  of the interconnection unit  144  in the correct positions. Preferably, the centering by means of the centering shoulder  280  or centering stub takes effect even when the heat sink  117  has assumed its end position on the platform  283 ; but this does not necessarily need to be the case any more because diode head wires have then usually already been threaded into the corresponding connecting contacts. In this end position, the ribs  244  and  247  are arranged on the right and left, respectively, of a guide connecting piece  225  and bring about a positionally correct assignment of the heat sink  117  with respect to the guide connecting piece  225  in the circumferential direction. Optional pins and/or snap-action hooks on the interconnection unit  144  or the webs  226  are directed towards the heat sink  117  and additionally engage in openings in order to keep the heat sink  117  on the interconnection unit  144  at least with frictional engagement and/or form-fitting engagement. 
     A structural unit  284  comprising the heat sink  53 , in the example three insulating sleeves  156 , three spacers  246  and three rivets  159  (tubular rivets), together with, in the example, three positive current rectifiers  147  (positive diodes) and the B+ bolt  153  is preassembled. In this case, first the positive current rectifiers  147  (positive diodes) are brought close to the receptacles  66  in order to be received (press-in diodes are pressed into the receptacles  66  in the form of cylindrical holes). The connecting contacts  239  (diode head wires) therefore protrude through the holes  74 . Preferably, the three spacers  246  are then positioned onto that side of the heat sink  53  on which the connecting contacts  239  (diode head wires) can be seen and on which contact is to be made with said connecting contacts. The stepped insulating sleeves  156  are plugged into the holes  74  from the other side (upper side) and then in each case one spacer  246 , one insulating sleeve  156  and one rivet  159  (tubular rivet) are fastened to one another at or in a hole  74 . A collar  286  of the rivet  159  then bears against a step  289  of the insulating sleeve  156  or against an end face  292  of a spacer  246 . This structural unit  284  is then positioned on the heat sink  117 , with the result that the collar  286  of the rivet  159  comes to bear in a cylindrical depression  238  in the heat sink  117 . The hook elements  235  in the process engage in each case around the undercuts  277  integrally formed on the guide connecting piece  225  in the described manner. At the same time, the connecting contacts  239  (diode head wires) of the positive current rectifiers  147  are guided towards the connecting contacts  201 ,  207  and  213  of the interconnection unit  144  and connected thereto. 
       FIG. 19  shows a side view (perpendicular to the axis of rotation  26 ) of the design of the cooling device or the rectifier. This side view shows, in the case of the interconnection unit  144 , emanating from the webs  226  and protruding downward, i.e. protruding away from the heat sink  117  on the side remote from the heat sink  117 , platforms  295 , which can also be seen in the view from below in  FIG. 16 . While the connecting contacts  201 ,  207  and  213  extend radially outwards and emanate from the webs  226  in the plane of said webs, the wire is bent back (downward) in the axial direction (direction of rotation  26 ) and in the direction pointing away from the heat sink  53  in the webs  226  in order to extend radially inwards and so as to emerge out of the platforms  295  after a certain distance. 
       FIG. 20  shows a three-dimensional illustration of the end frame  13 . 2 . This end frame  13 . 2  shows three fixing connecting pieces  298  (screw-type connecting pieces with an internal thread) which are used for receiving the rectifier device  139  for fixing to the end frame  13 . 2 . For this purpose, the resting faces  301 ,  304  and  307  illustrated in  FIG. 16  which are round and have a hole in the center (insert parts consisting of metal; see also  FIG. 18 ) are positioned onto in each case one fixing connecting piece  298 . In this case, the resting face  301  which is positioned next to the threaded sleeve  78  is placed onto the fixing connecting piece  298  which is depicted on the right in  FIG. 20 . The resting face  304  which is arranged between the two other resting faces  301  and  307  is positioned onto the central of the three fixing connecting pieces  298 . Several slot-shaped air exit openings  308  are located over the outer circumference of the end frame  13 . 2 . 
     The guide connecting pieces  225  illustrated in  FIGS. 15 and 16  are inserted into openings  228 ,  313 ,  316 ,  319 ,  322  and  325  as follows, with reference to  FIG. 16 : as already described in relation to  FIG. 11 , the small guide connecting piece  225  is inserted into the opening  228  which is arranged axially (axis of rotation  26 ) beneath the controller. This opening is introduced between a fixing connecting piece  328  (screw-type connecting piece with internal thread) and a dam  331  in the end region  334  of the end frame  13 . 2 . The controller  231  is held by the fixing connecting piece  328 . Correspondingly, the other guide connecting pieces  225  are inserted into said openings successively. 
     A hub  337  is integrally formed centrally on the end frame  13 . 2 , with the bearing  28  being inserted into said hub (see  FIG. 1 ). This hub is in this case connected with four struts  340  to the end region  334  of the end frame  13 . 2 . Four large openings  40  are located between the struts  340  and the end region  334 , through which openings cooling air is sucked, caused by the movement of the fan  30  during operation of the generator or the electrical machine  10 . Three of these openings  40  are provided with continuous recesses  346 , which are introduced on the radially outer edge  349 . The platforms  295  of the interconnection unit  144  protrude into these recesses  346  in such a way that they are at a common axial level (axis of rotation  26 ). That is to say that the platform  295  and possibly the connecting wire  216  extend in a plane formed from the openings (main openings)  40 , said connecting wire  216  then extending exclusively in this plane, for example. The form of the platforms  295  and the form of the recesses  346  are matched to one another. This means that the platforms  295  fill the recesses  346  completely or almost completely. One advantage of this arrangement is a usable opening  40  which is as large as possible with, where possible, a small effective edge proportion of the opening  40 . This has the effect that boundary effects induced by flow mechanics, such as interfaces reducing the cooling air throughput, for example, are formed to a lesser extent. Furthermore, at least one opening  40  (in this case three) adjoins a planar end-face region  352 , which is lower than other end-face regions  355 , when viewed axially from the outside. This has the advantage that, despite the web  226  possibly resting thereon, a relatively large gap is produced between the web  226  and the end frame  13 . 2 , with this gap reducing the flow resistance and thereby increasing the air throughput. In the case of a three-phase electrical machine  10 , three recesses  346  would be populated by corresponding platforms  295 , as in the case described here. In the case of a five-phase machine, five recesses  346  would be occupied by corresponding platforms  295 . However, it is not necessarily the case that one recess  346  needs to be provided per platform  295 . 
     The short guide connecting piece  225  already mentioned above necessitates a markedly shorter, preferably axial extent (axis of rotation  26 ) or length than the other stator terminals  364  on the side of the stator  16  with its stator core  17 , in whose slot a stator winding  18  with individual phase windings  358  is inserted ( FIG. 22 ) at one stator terminal  361 . Markedly shorter means, for example, 20 mm difference in length (for example installed state in the electrical machine). In the context of the present design, there is therefore a stator terminal  361  in the short guide connecting piece  225  beneath the controller  231 , while the other, in this case five, stator terminals  364  are inserted into the other (long) guide connecting pieces  225 . All of the stator terminals  361  and stator terminals  364  extend in the axial direction (axis of rotation  26 ), for example in the guide connecting pieces  225 . 
     The second exemplary embodiment described from  FIG. 13  onwards has an inner crosspiece  87 , which is arranged with respect to the axis of rotation  26  and at the same circumferential position on a larger radius than the inner edge  367 . This means that a central opening  370  of the rectifier device  139  is enlarged in the manner of a funnel away from the end frame  13 . 2  axially outwards. 
     In all of the exemplary embodiments, the bases  373  shown of the current rectifiers  147  and  150  illustrated by way of example as press-in diodes are directed away from the end frame  13 . 2 . 
     The heat sink  53  is produced integrally from a metal or a metal alloy by means of a pressure casting process. Aluminum or an aluminum alloy is used for this purpose. The same materials are used for the heat sink  117 .