PATENT ABSTRACT
A device for rectifying the current of a rotary electric machine comprising a bearing ( 50 ) with through openings ( 51 ) for a coolant, that comprises at least one module ( 100 ) including a holder ( 10, 16 ) for holding current rectifying members ( 93, 94 ) having the same phase as the machine, said holder ( 10, 16 ) including a heat sink ( 16 ) with vanes ( 18 ) at least partially covering an opening ( 51 ) in the bearing ( 50 ). A rotary electric machine including such a current rectifying device. Application: alternators of automotive vehicles with internal ventilation.

PATENT DESCRIPTION
CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM TO PRIORITY 
     This application relates to International Application No. PCT/FR2007/052582 filed Dec. 20, 2007, French Patent Application No. 0655844 filed Dec. 22, 2006 and French Patent Application No. 0754188 filed Mar. 30, 2007, of which the disclosures are incorporated herein by reference and to which priority is claimed. 
     DOMAIN OF THE INVENTION 
     The present invention concerns a device for rectifying the current of a rotary electrical machine, such as an alternator for a motor vehicle, containing a current rectifying device and a bearing of the rotary electrical machine provided with through-openings for a flow of coolant, such as air, and a rotary electrical machine, especially an alternator for a motor vehicle with internal ventilation, containing such a device. 
     STATE OF THE ART 
     Such a device and such a machine are described in the document WO 03/009452 (FR 2 827 437). 
     In this document, the rotary electrical machine is a polyphase alternator for a motor vehicle consisting of a casing carrying a stator surrounding a rotor which is integral with a shaft rotatably mounted in the casing. 
     The casing contains at least one front flange and one rear flange, each centrally carrying bearing means, such as a ball bearing, for rotary mounting of the shaft of the rotor. Such flanges are known respectively as the front bearing and the rear bearing. 
     The rotor is a toothed rotor or a salient pole rotor. 
     At least one excitation coil is associated with this rotor, preferably made from ferromagnetic material. 
     The stator consists of a body in the form of a stack of laminations carrying a polyphase stator coil. In one embodiment, the coil has conducting segments, and as a variant has a continuous wire. 
     Each phase of the stator and thus of the machine contains at least one winding. 
     The excitation coil, in one embodiment, is connected by wire connections to collector rings integral to the rear end of the rotor shaft. Brushes are allowed to rub against the rings. These brushes are carried by a brush holder which is usually integral with a voltage regulator. 
     In another embodiment, the excitation coil is fixed, the alternator having no brushes. 
     The extremities of the stator phases are connected to a current rectifying device carried by the rear bearing. A protective hood covers the rectifier device and is integral with the rear bearing. 
     The rectifier device/rear bearing assembly constitutes a rectifier. 
     The hood and the rear bearing are open-worked to allow circulation of a coolant, such as air, to the interior of the casing of the machine. 
     The rear bearing has a hollow form and consists of a bottom which is globally transverse-oriented in relation to the axis of the alternator combined with the axis of the shaft of the rotor. The bottom of the rear bearing contains through-openings for air. 
     This circulation of air is realised with the aid of at least one fan. In one embodiment, this fan is integral with the rotor. 
     As a variant, the fan is an external fan adjacent the front bearing, which is also open-worked. 
     As is known, when the excitation coil of the rotor is supplied with electricity and the shaft of the rotor rotates, the rotor is magnetised and an induced alternating current is generated in the stator coil. 
     This induced current is rectified into a direct current by the current rectifier device, in particular to recharge the battery of the vehicle and to supply the consumers of the on-board network of the vehicle with direct current. 
     The circulation of the air which is generated by the rotation of the fan or fans cools the rectifier device as well as the stator coil. 
     In the document WO 03/009452 the current rectifying device is provided with a current rectifying device containing diodes which are provided with a base, known as a cap, consisting of a solid main part, axially extended by a pedestal having at its free end a fixing face for a semiconductor element interposed between the pedestal and the head of a contact element in the form of a rigid wire, referred to as the tail of the diode or axis of the diode. The head of the tail of the diode and the semiconductor element are sheathed in resin. This resin is integral with the cap of the diode. 
     The current rectifying device carried by the rear bearing contains:
         a plurality of positive diodes supported by a positive holder carrying cooling vanes;   a plurality of negative diodes supported by the bottom of the rear bearing;   a connector to connect the tails of the diodes to the outputs of the stator phases.       

     The diodes constitute the current rectifying members. 
     In another embodiment, they are replaced by transistors of the MOSFET type. 
     The positive holder and the rear bearing are metallic, while the connector consists of a body made of plastic material in which partly uninsulated electrically-conductive tracks are embedded, in particular to create electrical contacts with the tails of the positive and negative diodes. 
     As can be seen in particular in FIG. 5 of this document WO 03/009452, the diodes extend parallel to the axis of the alternator and the connector is implanted radially above the electrically insulated positive holder carried by the rear bearing. 
     This device is satisfactory. 
     In another embodiment described in the document FR 2 729 802, the diodes do not have any tails. 
     As can be seen in  FIG. 1 , which is a frontal view of a rectifier device for an alternator of a motor vehicle without the alternator hood, this document proposes mounting positive diodes  20  and negative diodes  30  on the cooling plates  10 . 
     In this  FIG. 1  can be seen the rear alternator bearing  50 , the electrically-insulating parts  40  to insulate the plates  10  of the bearing  50 , the terminal  70 , referred to as terminal B+, of the alternator, which corresponds to the rectified output of the alternator designed to be connected via a cable to the positive terminal of the battery, the reeds  80 , the fixing screws  90  for the plates  10  on the bottom of the bearing  50 , the regulator-brush holder assembly  14 , the through-openings  51  for air and the cylindrical core  52  internally delimiting the openings  51 . 
     Each plate  10  is connected via a contact  11  to one of the phase outputs of the stator coil and is in contact with the anode of the positive diode  20 , which it carries, and with the cathode of its negative diode  30 . 
     The contact  11  passes through the plate  10  by means of an orifice  12  thereof. 
     For further details, please refer to this document FR 2 729 802. 
     This configuration enables the through-openings for air to be left clear and modules to be created in the form of plates carrying positive and negative diodes. 
     In the two aforementioned embodiments, the diodes are oriented axially in relation to the axial axis of symmetry of the alternator bearing. 
     Nevertheless, a problem arises in these aforementioned embodiments, because the alternator is installed under the bonnet in proximity to the thermal engine of the motor vehicle. 
     In fact, in view of the development of thermal engines for vehicles which are more and more confined, the ambient temperature under the bonnet is increasing more and more. 
     In certain cases, this ambient temperature can reach 140° C. 
     So it is desirable to be able to adapt these aforementioned current rectifying devices to these higher temperatures. 
     It is also desirable to increase the power of the rotary electrical machine. 
     The same problem arises when the thermal engine is fixed and is confined to the interior of a compartment. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to meet these requirements. 
     One aim of the present invention is therefore to create a current rectifying device which works at higher ambient temperatures. 
     Another object of the invention is to increase the power of the machine. 
     According to the invention, a current rectifying device for a polyphase rotary electrical machine provided with an axial axis of symmetry, of the type consisting of a current rectifying device and a bearing belonging to the rotary electrical machine and containing a bottom globally transverse-oriented in relation to the axial axis of symmetry of the machine, said bottom being, firstly, provided with through-openings for a coolant, and secondly, carrying the electrically insulated current rectifying device containing at least one module consisting of a holder carrying the current rectifying members having the same phase of the machine, is characterised in that the holder of the module contains a heat sink with vanes and in that the vanes of the heat sink at least partially cover an opening of the bearing. 
     According to the invention, a rotary electrical machine, in particular an alternator for a motor vehicle with internal ventilation of the type indicated above, is characterised in that it contains such a current rectifying device. 
     With the aid of the invention, the current rectifying members are effectively cooled, since the heat sink extends the holder transversely towards the interior and is positioned in the flow of the coolant, such as air. 
     The current rectifying members also have an axis of symmetry which extends transversely so as to enable the axial volume requirement of the machine to be reduced. 
     With the aid of the invention, the bearing of the machine can be standardised. 
     In one embodiment, the heat sink is provided with fine vanes. 
     These vanes extend, in one embodiment, globally perpendicularly to the semiconductor elements of the current rectifying members. 
     The bottom of the current rectifying members, such as the bottom of the bases of the diodes, may thus transmit heat to the heat sink. 
     In one embodiment, this bottom is in direct contact with the heat sink. 
     In another embodiment, the bottom of the current rectifying members, such as the bottom of the bases of the diodes, may be used to assemble the heat sink, for example by gluing or soldering. 
     According to still other characteristics:
         in one embodiment, the heat sink with vanes contains a base;   in one embodiment, the base carries the current rectifying members;   in another embodiment, the base is separate from a part carrying the current rectifying members;   the base may be joined onto this part carrying the current rectifying members by soldering, welding or gluing;   as a variant, the base is fixed to this part with the aid of at least one fixing member, such as a screw, or by crimping, or by latching;   in one embodiment, a thermally-conductive element is interposed between the base and the part carrying the current rectifying members, such as diodes or transistors of the MOSFET type;   in one embodiment, this part consists of a plate;   in one embodiment this plate contains protuberances to receive the bases of the current rectifying members of one phase of the machine.       

     Obviously, all of the aforementioned characteristics can be considered in isolation and/or in combination. 
     In all cases, it is possible to increase the power of the machine, since the current rectifying members are better cooled. The machine can operate in an environment with a higher temperature. 
     Other characteristics and advantages of the invention will become apparent from reading the detailed description which follows, which will be better understood by making reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a frontal view of a current rectifying device for a motor vehicle alternator of prior art; 
         FIG. 2  is a frontal view, similar to  FIG. 1 , of a current rectifying device for a motor vehicle alternator according to the invention; 
         FIG. 3  is a partial sectional view along the line  2 - 2  of  FIG. 2 ; 
         FIG. 4  is a view similar to  FIG. 3  without the rotor and without the winding of the rotary electrical machine; 
         FIG. 5  is a view of the module of the current rectifying device from  FIG. 4 ; 
         FIG. 6  is a perspectival view of the module from  FIG. 5 ; 
         FIG. 7  is a partial view similar to  FIG. 4  showing part of the contact means of the module—to earth and to the phase respectively; 
         FIG. 8  is a diagram of part of the electrical circuit of the current rectifying device; 
         FIG. 9  is a partial view similar to  FIG. 3  for another embodiment; 
         FIG. 10  is a partial top view of a module mounted on its bearing, showing a variant fixation of the heat sink on its module; 
         FIG. 11  is a partial perspectival view of the variant fixation from  FIG. 10 , showing a variant of an electrical contact of a negative diode with the bearing; 
         FIG. 12  is a view similar to  FIG. 11  for yet another embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the figures, common or similar elements will be assigned the same reference numbers. 
     In  FIGS. 2 to 4 , the rotary electrical machine shown is a polyphase alternator for a motor vehicle with internal ventilation, for example of the type as described in the aforementioned documents EP 0 515 259 and WO 03/009452, in which the current rectifying device has been replaced by that of the invention, which takes up less space axially and cools better. 
     The alternator shown in  FIG. 2  contains 6 phases and 6 AC-DC rectifier modules according to the invention at the rate of one module per phase. 
     These modules  100  are carried, here with electrical insulation in the way described below, by the bottom  56  ( FIGS. 3 and 4 ) of the rear bearing  50  of the alternator. 
     This bearing  50  is metallic here, preferably in mouldable material such as aluminium. The bearing  50  is electrically connected to earth. 
     The current rectifying modules belong to the current rectifying device and thus to the current rectifying device according to the invention. 
     This device contains the current rectifying device which is integral with a flange of the alternator, in this case constituted by the alternator rear bearing. 
     The rectifying device-rear bearing assembly thus constitutes the current rectifying device. This device forms a unitary assembly which can be handled and transported. 
     The number of modules  100  is a function of the number of phases. 
     So, for a three-phase alternator, the number of modules is three, for a pentaphase alternator the number of modules is 5. 
     In the example shown, 1 to 6 modules  100  can be mounted, with the presence of the brush holder-voltage regulator assembly  14 . 
     So the current rectifying device according to the invention contains at least one module, and in one embodiment the alternator can be of the monophase type. 
     According to one characteristic, each module  100  contains a holder  10 ,  16  for the current rectifying members  93 ,  94 . 10  associated with one phase of the alternator. 
     Each holder  10 ,  16  is designed to be electrically connected to the output of the phase concerned. 
     The holder  10 ,  16  is electrically and thermally conductive. 
     The holder contains a part carrying the current rectifying members  93 ,  94 . 
     In the embodiment in  FIGS. 2 to 7 , the holder  10 ,  16  contains a plate  10  constituting the supporting part for current rectifying members. 
     The plate  10  is metallic in this case and carries the current rectifying members  94 ,  93  of the phase concerned. 
     In this embodiment these members  93 ,  94  consist of positive and negative diodes as in  FIG. 1 . 
     The positive diode  93  is designed to be electrically connected to the terminal B+, while the negative diode  94  is designed to be connected to earth here ( FIGS. 3 and 4 ) via the bottom  56  of the rear bearing  50 . 
     The anode of the positive diode  93  is in electrical contact with the plate  10  and the same applies for the cathode of the negative diode  94 , as can be seen better in  FIG. 8 . This figure shows three phases P 1 , P 2 , P 3 , triangle-mounted, of the stator of the rotary electrical machine. 
     The machine contains three other triangle or star-mounted phases here, as described in document U.S. Pat. No. 4,163,187. Of course, it is possible to double the number of grooves in the body of the stator. Of course, the machine may consist of just three phases and three modules in the aforementioned manner. 
     An electrically insulating part  40  is inserted between the plate  10  and the bearing  50  ( FIGS. 3 and 4 ). 
     According to one characteristic of this embodiment, the holder  10 ,  16  of a module  100  contains a heat sink  16  which extends towards the centre of the machine, i.e. globally transversely. 
     In this embodiment the plate  10  is prolonged towards the interior by the heat sink  16 , which is integral with the plate  10 . 
     This heat sink  16  is metallic in this case, for example having an aluminium or copper base. 
     This heat sink  16  is integral with the plate  10  and at least partly covers an opening for the passage of air  51  so that the module  100  is well cooled. 
     In one embodiment the heat sink  16  may extend so as to overlap two openings  51  and partly cover these. 
     In this case, the heat sink entirely covers an opening  51  so that it is even better cooled. 
     These openings  51 , in the embodiment from  FIG. 2 , are identical in shape. 
     According to one characteristic, the current rectifying members  93 ,  94 , in this case diodes, and the heat sink  16  extend on either side of the plate  10 . 
     According to one characteristic, the heat sink  16  is arranged in the flow of coolant, in this case air. This flow is generated by the rotation of a fan  57 . 
     This fan  57  can be seen more easily from  FIG. 3 . This figure has arrows representing the circulation of the cooling air generated by the rotation of the fan  57 , which is equipped with blades  570 . 
     In this figure can be seen, as  58 , part of the rotor of the alternator. This rotor  58  is in this case a toothed rotor or as a variant, a salient pole rotor. 
     The fan  57  is integral with the rear end of the rotor  58 . This fan  57  is, in this case, a high-powered fan. This fan  57  contains a large number of blades  570  and in this case is of the type as described in the document WO 2004/106748. It thus contains two basic fans, one on top of the other, each fan containing a flange provided with a plurality of blades  570  preferably distributed at irregular intervals to reduce noise. This fan  57  is attached, for example by welding, to the rear end of the rotor  58 , here with the aid of welding spots belonging, for example, to the flange of the internal basic fan. The basic external fan is attached to the internal fan, for example, using welding points or adhesive. These basic fans are metallic in this case. 
     The fan  57  here is of the centrifuge type. 
     The blades  570  spin past the openings  51  to draw in fresh air and expel the air by means of air outlet openings  53  described below. 
     In this  FIG. 3  can be seen, as  61 , the shaft which is integral with the rotor  58  and as  59  the collector rings carried by the rear end of the shaft  61 . These are the rings rubbed against, in conventional manner, by the brushes carried by the brush holder connected to the voltage regulator of the assembly  14 . 
     The X-X axis constitutes the axial axis of symmetry of the shaft  61  and that of the machine. 
     The heat sink  16  extends transversely in relation to this axis. 
     It can be seen that the rear bearing  50  is hollow in form and contains a bottom  56 , globally transverse-oriented in relation to the X-X axis. This bottom is prolonged at its external periphery by a rim  55  globally axially-oriented in relation to the X-X axis. 
     The openings  51  here are air inlet openings. In this case the openings are globally trapezoidal in shape and are delimited radially towards the interior by the cylindrical core  52  of the axis combined with the X-X axis. 
     The bottom  56  of the bearing  50  contains a continuous part at the exterior of the openings  51  to mount the plates  10  of the modules  100  here. 
     The internal periphery of the core  52  delimits the central opening of the bearing  50 . This opening is used as a passage for the rear end of the shaft  61 . 
     The internal periphery of the core  52  is also used to mount the ball bearing  60  interposed radially between the external periphery of the shaft  61  and the internal periphery of the core  52  for the rotatable mounting of the shaft  61 . A capsule  62  is interposed radially between the internal periphery of the core  52  and the external periphery of the ball bearing  60  to absorb expansion differences. 
     The rim  55  is provided with a plurality of air outlet openings  53 , axially oblong in shape. 
     The number of openings, in this case the air outlet openings  53 , in this embodiment is greater than the air inlet openings  51 . 
     Each series of openings  51 ,  53  consists of a plurality of openings separated from each other by arms, oriented radially for the openings  51  and oriented axially for the openings  53  respectively, which as variants may be inclined axially, bearing in mind that the openings  53  here affect the external periphery of the bottom  56 . 
     For greater clarity, the stator and its coil have not been shown here, so that the course of the air can be seen. 
     As a variant, the rim  55  has no openings  53  and, in the way known in the art, a fan is installed at the front of the alternator, the course of the air in this case being axial. 
     In  FIGS. 2 and 3 , similarly, the protective hood covering the assembly  14  and the current rectifying device with modules  100  have not been shown. 
     Each electrically conductive plate  10  is axially oriented in relation to the X-X axis, as can be better seen in  FIGS. 3 and 4 . 
     The plate is in indirect contact with the bottom  56  via its edge, with interposition of the electrically insulating member  40 , while the bearing  50  is electrically conductive and is connected to earth. 
     According to one characteristic, the lower edge  101  ( FIG. 4 ) of the plate  10  thus extends globally perpendicularly to the bottom  56 . 
     This plate  10  thus extends globally perpendicularly in relation to the bottom  56  of the bearing  50  with the result that, as can be seen in  FIG. 6 , its upper face  103  carries the current rectifying members  93 ,  94  and its lower face  102  the heat sink  16 , arranged in the flow of air generated by the rotation of the fan  57 . 
     The holder  10 ,  16  thus includes a part  10 , which extends perpendicularly in relation to the bottom  56  of the bearing  50 . 
     The heat sink  16  contains a plurality of vanes  18 , as can be better seen in  FIG. 2 . The vanes  18  are integral with a base  19  which the heat sink  16  presents adjacent the lower face  102  of the plate  10 . 
     These vanes  18  are fine. In this case, the vanes  18  have been obtained by moulding with the base  19  presented by the heat sink  16  adjacent the lower face  102  of the plate  10 . 
     This heat sink  16  has a globally trapezoidal shape, the large foundation of which, constituted by the base  19 , is adjacent the plate  10 . 
     The globally trapezoidal shape of the heat sink is obtained, in one embodiment, by means of vanes  18 , which have different lengths, as can be better seen in  FIG. 6 . 
     In one embodiment, the heat sink  16  is all of a piece with the plate  10 . In this case, the holder  10 ,  16  of the current rectifying members  93 ,  94  is all in one piece. The base  19  is merged with the plate  10  and carries the current rectifying members. This base is perpendicular to the bottom  56  of the bearing  50 . 
     This heat sink is, for example, obtained by moulding with the plate  10 . The plate  10  and the heat sink are, for example, made of aluminium. 
     In another embodiment, the base  19  is distinct from the plate  10 . The base  19  is attached to the plate  10 . 
     So, as a variant, the heat sink  16  is attached by means of its base  19  to the plate  10 . 
     In one embodiment, the heat sink  16  is attached to the plate  10  by means of at least one fixing member  92 , such as a screw, a bolt or a pin. 
     In the embodiment shown, this is realised by means of three screws  92  inserted in the form of a triangle and screwed into the base  19 . 
     As a variant, the base  19  of the heat sink is welded, soldered or glued onto the lower face of the plate  10 . The adhesive is thermoconductive. 
     In another variant, the heat sink is attached by latching onto the plate. For example, the base  19  contains hooked fasteners, which each pass through an opening of the plate to engage with the upper face of the plate. 
     In yet another variant, the base  19  of the heat sink is attached to the plate by means of crimping. 
     In the embodiment shown, a heat-conducting member  17  is interposed between the plate  10  and the heat sink  16 . In this case, the member  17  is interposed between the lower face  102  of the plate and the upper face of the base  19  and is tightened using means of fixation  92 . 
     The member  17  may consist of thermoconductive adhesive. 
     As a variant, the member  17  consists of a sheet of thermally conductive plastic material known as a thermal pad. 
     In general, the electrical function of the module  100  is realised by means of the plate  10 , constituted as a variant by the base  19 , and the current rectifying members  93 ,  94 , while the function of dissipation of heat is realised by the heat sink  16  positioned in the airflow. 
     In the embodiments described, the heat sink is not electrically insulated with respect to the plate  10  carrying the current rectifying members  93 ,  94  and good thermal conduction is effected between the current rectifying members  93 ,  94 , carried by the plate  10  which is also thermally conductive, and the heat sink  16 . 
     Of course, the heat sink may be electrically insulated in relation to the plate equipped with the members  93 ,  94  while still having good thermal conduction. 
     So in one embodiment, the member  17  is also electrically insulating. 
     In one embodiment, this member consists of electrically insulating and thermally conductive adhesive. 
     As a variant, the member  17  is a thermal pad, which is electrically insulating. 
     This pad is, for example, covered on each of its faces by a layer of electrically insulating and thermally conductive adhesive to fix it onto the plate  10  and the base  19 . 
     In one embodiment, this pad is clamped between the base  19  and the lower face  102  of the plate, this clamping being effected by means of at least one fixing member  92 , such as a screw, a bolt or a pin fixing the plate to the base. 
     In this case, electrically insulating base portions must be provided, of the type which can be seen as  199  in  FIG. 3 . 
     More precisely, as can be seen in  FIG. 9 , this base portion  399  includes a head  499  in the form of a washer as a rest for the head of the fixing member  92 , such as a screw or a bolt, prolonged by a sleeve  599  penetrating into a through-hole of the plate (no reference number) to electrically insulate the shank of the fixing member with respect to the plate. The base then includes a hole  119  which is threaded when the fixing member  92  is a screw or smooth when the fixing member is a bolt. Three screws  92  may be provided and inserted as can be seen in  FIG. 6 .  FIG. 9  shows a partial view of the body  155  of the stator carrying the stator coil  156 , projecting in relation to the body  155  to form a coil end  156  at each axial end of the body  155 . 
     Obviously, it is possible to invert the structures, the head of the fixing member being situated alongside the lower face of the base, the threaded hole or the hole through which passes the shank of the organ  92  being created in the plate. This structural inversion is applicable in all cases, with or without the member  17 . 
     As a variant, this pad  17  may be clamped and fixed by means of elastic electrically insulating clips resting on the upper face of the plate  10  and on the lower face of the base  19 . 
     This mode of fixation is applicable in all cases, with or without the member  17 . 
     The plate  10 , and thus the holder  10 ,  16 , contains at least one protuberance  15  to fix it onto the rotary electrical machine, in this case on the bottom  56  of the bearing  50 . 
     Here the protuberance extends in the opposite direction to the heat sink  16 . 
     This protuberance  15  extends here perpendicularly to the plate  10 . 
     The protuberance  15  consists of a perforated disc through which passes a fixing member  91 , here in the form of a screw. The disc  15  extends centrally from the bottom part of the plate, which in this case is globally rectangular in shape. 
     The base  19  also has a globally rectangular shape. 
     The disc  15  extends parallel to the bottom  56  of the bearing  50 . 
     The plate  10  equipped with its disc  15  is obtained, for example, by cutting and folding. 
     An electrically insulating part  40  is interposed between the module  100  and the bottom  56  of the bearing  50 . 
     This part  40  is provided with an opening  41  which is identical in shape to that of the opening  51  associated with the module  100 . This part exhibits a variation in thickness forming an indentation  42  corresponding to the shape of the module  100  to accommodate the module and hold it by wedging. 
     The part  40  thus contains an indentation to receive the disc  15 . 
     The base  19  and the plate  10  are in contact with the part  40  by their edge. This part  40  may be separate, being associated with each module. In this case, the part  40  is common to all the modules  100 , as can be seen in  FIG. 2 . So it is also interposed between the assembly  14  and the bottom  56  and has openings corresponding to those of the bottom  56 . 
     It will be noted that the means of fixation  91 , such as screws, are electrically insulated in relation to the plate  10 . Thus, one can see as  199  in  FIG. 3  an electrically insulating base portion enabling the screw  91  to be insulated from the plate  10 . This base portion has an annular head on which rests the head of the screw  91  which is screwed into the threaded hole  150  of the bottom  56  and a sleeve penetrating into the hole through which passes the shank of the screw  91 , said hole being created in the disc  15  in order to insulate the shank of the screw from the disc. The shank of the screw passes through the part  40  provided with an opening for this purpose. 
     In one embodiment, the part or parts  40  are also thermally insulating when the bearing  50  is hotter, while functioning, than the module  100 . As a variant, the part or parts  40  are thermally conductive when the bearing is colder, while functioning, than the module  100 . 
     Everything depends on the temperature attained during functioning by the stator, which in one variant may be carried by an intermediate part of the casing of the machine interposed between the front and rear bearings, said intermediate part being cooled by circulation of the coolant fluid. 
     In the light of  FIG. 6 , the compactness of the solution can be appreciated, the diodes  93 ,  94  each being installed between two means of fixation  92 , while the disc  15  is long enough to avoid any interference between the diodes  93 ,  94  and the fixing member  91  extending in a plane perpendicular to the diodes  93 ,  94 . 
     It will be noted that each diode  93 ,  94  has a tail  96 ,  97 , which extends in the opposite direction to the heat sink  16 . 
     These tails  96 ,  97  are, in this case, identical in length and extend parallel to the fine vanes  18 , as can be better seen in  FIG. 6 . 
     These vanes  18  extend perpendicularly to the base  19  and have decreasing lengths at the ends of the base  19  to provide the heat sink with a globally trapezoidal shape. 
     These diodes have a cap  98  provided with a bottom  99 . The heat sink  16  has vanes  18  extending perpendicularly to the plate  10  and to the bottoms  99  of the caps  98  of the diodes  93 ,  94 . 
     Improved evacuation of heat is thus effected, since the bottoms  99  contribute to the evacuation of heat by the fact that they are in contact with the thermally conductive member  17 , or as a variant, directly with the heat sink  16 . This heat is evacuated by the heat sink which is positioned in the air flow. 
     So there is better evacuation of heat by positioning the heat sink  16  on one side of the plate and the current rectifying members on the other side. 
     Moreover, the solution is more compact axially than that in the document WO 03/009452, since the tails  96 ,  97  of the diodes  93 ,  94  are oriented transversely towards the exterior and not axially. 
     The axis of symmetry  95  of the tails  96 ,  97  and of the diodes  93 ,  94  also extends perpendicularly in relation to the plate  10  and to the base  19 . The axes  95  are oriented transversely in relation to the X-X axis. 
     The caps  98  of the diodes in this case are milled for a forced fit in the associated opening  198  of the plate  10 , this type of diode being known as a “pressfit diode”. 
     As a variant, the diodes may be soldered or glued onto the plate. 
     Obviously, the opening  198 , as a variant, is a blind hole so that the bottoms  99  of the diodes are in contact with the plate  10  and also with the heat sink when the latter is all in one piece with the plate. 
     As a variant, the opening  198  may be prolonged by a blind hole made in the base  19  of the heat sink  16  as can be seen in dotted outline as  298  in  FIG. 5 . 
     The milled part of the diode then extends into this blind hole  298  and participates in fixing the heat sink  16 . 
     As a variant, the opening  198  is a through-hole, but the bottom  99  is at a distance from the heat sink  16 . 
     All combinations are possible. For example, in one embodiment, the cap  98  of the diode projects in relation to the lower face  102  of the plate  10  so that a space exists between the base  19  of the heat sink  16  and the plate  10 , the bottoms  99  of the diodes integral with the plate  10  serving, for example by gluing or soldering, to fix the heat sink  16 . 
     The space serves to provide effective cooling. 
     The diodes which are integral with the plate may thus serve to fix the heat sink. 
     Of course, the pad  17  may be perforated in the area of the bottoms of the diodes for direct contact with the base of the heat sink, the assembly of the plate with the base being created by the aforementioned means, for example, by crimping, latching, clamping, gluing, welding or soldering. All combinations are possible. 
     Obviously, the tails  96 ,  97  of the diodes  93 ,  94  may have a different length in order to utilise diodes of prior art. 
     As a variant, the diodes have no tails. 
     In general the diodes  93 ,  94  are better cooled due to the fact that they are associated with the vanes  18  of the heat sink  16  which are transversely long and the axial volume requirement is reduced due to the orientation of the diodes. 
     These diodes can be replaced by MOSFET transistors so that the current rectifying members are not necessarily diodes. These members always contain a semiconductor member  200 , represented by dotted lines in  FIG. 6 , which extends perpendicularly to the vanes  18  and parallel to the plate  10 . 
     As will be apparent from the description and from the drawings, the current rectifying members are installed at the external periphery of the bottom  56  of the rear bearing  50 , at the exterior of the air inlet openings  51  so that these openings or louvres of the rear bearing are clear and the radial length of the vanes  18  of the heat sink is as long as possible transversely. 
     Obviously, by using discs  15 , the plate  10  can be installed lower down towards the centre, the vanes  18  then being shortened. 
     The external periphery of the bottom  56  may have an inclined portion. 
     The module or modules  100  are well cooled so that the rectifier device, containing the modules  100  and the bearing  50 , can operate at higher temperatures. 
     The power of the machine can be increased due to the improved cooling of the module or modules  100 . 
     A very good thermal equilibrium of the rectifier device containing the bearing  50  equipped with several modules  100  is achieved, because standardised modules  100  are used. 
     The invention makes it possible to omit phase connectors. 
     So, in one embodiment, the output of the phase associated with the module  100  concerned is connected directly to the plate, for example being fixed by welding onto the plate. 
     Likewise, the tail of a negative diode may be connected by a wire contact to the bearing  50  which is earthed. 
     In another embodiment ( FIG. 7 ), part of the annular head  299  of the base portion  199  is drawn out in order to fit a first metallic washer  301  in contact with the head of the screw  91  either side of this head and a second washer  302  in contact with the disc  15  which is electrically insulated from the bottom  56  of the bearing by the part  40 . 
     The washers  301 ,  302  are electrically insulated from each other by the head of the base portion  199 . 
     In one embodiment, the first washer  301  belongs to a first electrical contact  310  with a short length ( FIG. 8 ) connected to the diode tail  97  of the negative diode  94 . This washer  301  is earthed via the screw  91 . The second washer  302 , in contact with the disc  15  of the plate  10 , belongs to a second electrical contact  110  ( FIG. 8 ) connected to the phase P 1 , P 2 , P 3  concerned. 
     The disc  15  and the fixing member  91  thus also act as electrical contact of the module  100 , with the phase and earth respectively. 
     As shown in diagram form in  FIG. 8 , the tail  96  of each positive diode  93  can be electrically connected to the terminal B+ via an arc-shaped electrically conductive member  320 . 
     This member  320  is integral with the terminal B+, not shown for the sake of simplicity in  FIG. 2 . Reeds  321  or other rigid contacts connect each tail  97  electrically to the member  320  of the rigid type. 
     Obviously the reeds  321  and the member  320  can be embedded in plastic material in order to be electrically insulated, while being uninsulated locally at the level of the tails  97  and of the terminal B+. 
     Obviously, the present invention is not limited to the embodiments described. So, as a variant, the machine may be brushless so that there is no need for a brush holder, which may allow a seventh module to be fitted. The voltage regulator may even be mounted elsewhere and thus supplementary modules may be mounted. 
     The bearing  50  may be standardised and receive a number of modules depending on the applications. 
     As a variant, the modules can be supported by the bottom of the front bearing of the machine. A module can be created to rectify the neutral point when the phase outputs are star-connected. 
     The plate  10 , which is rectangular in shape in the figures, may have a different shape, preferably oblong. The same applies for the base  19 , which advantageously matches the shape of the plate  10 . 
     The disc  15  can be replaced by lugs installed at the ends of the plate. 
     Slight inclinations may be provided. Thus the plate extends globally perpendicularly to the bottom  56  and the vanes  18  extend globally perpendicularly to the plate  10 . 
     Obviously, in the aforementioned way, the diodes or other current rectifier members may serve to fix the heat sink  16  or participate in the fixation of the heat sink, for example using means of fixation  92 . 
     The diodes may extend either side of the plate and serve to fix the heat sink. 
     The heat sink is attached to the plate or at a slight distance therefrom. 
     The structures may be inverted, so in the embodiment shown in  FIG. 10  the heat sink  16  is made integral with the plate  10  of the module  100  by latching using at least one hooked fastener separate from the heat sink  16 . 
     More precisely, in the embodiment shown in  FIG. 10 , the plate  10  of the module  100  is made integral with the heat sink  16  by latching using an electrically insulating plate  400 , which rests on the external face of the plate  10  of the module and has at least one deployable hooked fastener  401 . The hook of this fastener is designed to engage with the external edge  280  of an aperture  180  delimited by two consecutive vanes  18  of the heat sink  16 . 
     As can be seen from  FIG. 11 , this electrically insulating plate  400  has a clearance  402  for the current rectifying members  93 ,  94  of the module  100 . This clearance is in the form of an oblong hole in this case. 
     Here the plate  400  has two hooked fasteners  401  extending above the heat sink  16  to engage by their hook with the external edge  280  of an aperture  180 . The fasteners are installed in proximity to the lateral edges of the plate  400 , which in this case covers the plate  10  of the module  100 . 
     As will have been understood, the plate  400  with hooked fasteners  401  allows the plate  10  of the module in contact with the member  17 , such as thermoconductive adhesive or a thermoconductive pad, to be tightened. 
     The first electrical contact  310 , as a variant, includes, as can be seen in  FIG. 11 , a projection  250  carried by the bearing  50 . In this embodiment, the bottom  56  of the bearing  50  has axially oriented projections  250  to form an electrical contact of the tails  97  of the negative diodes  94  with the bearing  20 . 
     This contact is created by welding, crimping, latching or clamping the tails in the projections which have an aperture  260  for this purpose at their free ends to receive the tail concerned. 
     As a variant, the projection  250  consists of a conduit obtained by moulding with the bottom  56  and carrying an attached copper member, for example in the form of a nail sunk into the conduit, for connection by welding or any other means, of the end of the tail  97  of the negative diode  94  with the head of the nail. 
     As a variant, the projection is attached to the bottom  56  of the bearing  50 , for example by welding, riveting, screwing or any other means. This projection consists, for example, of a copper member joined to the bottom  56 , for example by riveting or welding, and having a head affixed, for example by welding, to the end of the tail  97  of the negative diode  94 . 
     As a variant, as can be seen in  FIG. 12 , the second electrical contact with the phase concerned contains an electrically conductive reed  240 , in this case L-shaped or as a variant, T-shaped, fixed onto the upper face  103  of the plate  10  of the module  100 , for example, by welding or gluing. 
     As a variant, as can be seen in  FIG. 9 , the electrically conductive reed  302  is retained and the electrically conductive reed  302  from  FIG. 7  is omitted. In this case, the hole in the disc  15  is threaded to screw in the screw which passes through an opening of the electrically insulating member. The bottom  56  then presents, in correspondence with the holes in the disc  15  and the member  40 , a clearance of greater diameter, such as a blind hole  225  or in this case, a through-hole to avoid any contact of the screw  91  with the bearing  50 . 
     The contact between the tails  97  of the diodes  94  and the bearing can be realised using projections of the type shown in  FIG. 12 . 
     All combinations are possible. 
     The fan  57  may be of the centripetal type, so that the openings  51  are, in this case, outlet openings and the openings  53  are air inlet openings. 
     In another embodiment, the fan is a simple fan. 
     It may have axial and radial action. 
     Two internal fans may be provided, as in the previously cited document EP 0515 259. 
     As a variant, a single internal fan is provided. 
     As will be apparent from the description and the drawings, the external periphery of the bottom  56  is recessed, because it does not receive any diodes. This external periphery may have an inclined portion in order to direct air towards the stator coil, more precisely towards the projecting end referred to as the coil end of this coil, by means of the openings  53 . 
     Obviously, as a variant, the module  100  may carry a different electronic component. 
     Equally, the thermal engine may, as a variant, be a fixed thermal engine. 
     This engine may be confined in a compartment. 
     The alternator is, in one variant, reversible. This type of alternator is called an alternator-starter and in particular is used to start the thermal engine. 
     In this case, MOSFET type transistors are used instead of the diodes  93 ,  94 . 
     Obviously, in  FIGS. 10 to 12 , the heat sink-module assembly may be attached with electrically insulating glue to the bottom of the bearing so that the presence of the protuberance or protuberances  15  is not obligatory. 
     As a variant, electrically insulating screws may be used to affix this assembly to the bearing concerned of the casing of the machine using one or more protuberances  15 . 
     As a variant, the plate  10 , and thus the holder  10 ,  16 , contains protuberances. 
     For example the plate contains two protuberances each facing a milled cap of a diode  93 ,  94  fitted by force into a blind hole of the relevant protuberance of the plate  10 , so that the bottom of the cap is in contact with the bottom of the blind hole and transmits heat in the aforementioned manner. 
     In one embodiment the protuberances receiving the caps of the diodes project in relation to the upper face of the plate. 
     In another embodiment the protuberances receiving the caps of these diodes project in relation to the internal face of the plate while staying in contact with the member  17 . There is thus a clearance between the protuberances. 
     In this case the member  17  may be in two parts, each part being associated with one protuberance. 
     The clearance may be arc-shaped. 
     Hence, the part  10  carrying the current rectifying members need not necessarily be in the form of a plate. 
     Obviously, as a variant, the bearing  50  carrying the module(s) has a flat shape and constitutes a cover closing off the other part of the casing of the machine. 
     The heat sink  16 -modules  100  assembly or assemblies may, instead of projecting towards the exterior in relation to the front or rear bearing  50  concerned, project towards the interior in relation to the bearing concerned. 
     The heat sink-module assembly or assemblies may thus extend to the interior of the machine. 
     The hood of the machine is, as a variant, constituted by the rear bearing. 
     Obviously, the different modes of fixation of the heat sink  16  with its plate may be combined. 
     So at least one of the fixing members  92  may be replaced by fixation using a diode or partial gluing. The diodes may be used to fix the heat sink in the aforementioned manner in combination with gluing or fixing by crimping, or using clips or latching with a single hooked fastener. 
     The fixing members may consist of rivets. 
     Fixation by gluing may be realised in several parts in combination, for example, with fixation by means of a fixing member. 
     Equally, a pad may be combined with gluing of several parts. 
     It will be appreciated that the holder  10 ,  16  carries the current rectifying members  93 ,  94  having the same phase, which enables the volume requirement of the current rectifying device to be reduced and cuts down on the number of parts, because there is no need to provide one heat sink for the positive diode and another for the negative diode. The heat sink according to the invention is common to both diodes. Moreover, the existing openings  51  are used, without the need to create other openings and damage the mechanical strength of the bearing.