FR2938132A1 - Rotary electric machine e.g. alternator, for combustion engine of motor vehicle, has electrical connecting body comprising U-shaped electrically conductive element partially drowned by molding in electrically insulating material - Google Patents

Abstract

The machine has a stator (16) including a star-shaped electrical winding (18) provided with a set of electrical conductors. An end of each conductor forms an electrical neutral point of the electrical winding. An electrical connecting body (90) electrically connects two neutral points of the winding of the stator. The electrical connecting body comprises a U-shaped electrically conductive element partially drowned by molding in an electrically insulating material. A crown of the electrical connecting body is made of the electrically insulating material.

Description

Rotating electric machine

The invention relates in particular to a rotating electrical machine, in particular an alternator or an alternator-starter for a motor vehicle. US Pat. No. 7,170,210 discloses an alternator comprising a stator provided with an electric winding forming several phases. Phase inputs are formed on busbars.

On some electrical machines, it may happen that neutral points or outputs or phase inputs of the stator winding are located very close to a bearing of the machine. This can increase the risk of accidental electrical contact between a winding conductor and the bearing. Patent application FR 2 780 828 discloses an alternator comprising a housing, a stator winding and an electrically insulating part interposed between the housing and the winding. The invention aims in particular to provide a new type of conductor winding of the stator winding vis-à-vis a bearing of the machine. The subject of the invention is thus a rotating electrical machine, in particular an alternator or an alternator-starter for a motor vehicle, comprising: at least one bearing provided with at least one opening opening outside the bearing, a stator comprising an electric winding, this winding comprising a plurality of electrical conductors and at least one of these conductors comprising an end forming an electrical neutral point of the winding, - an electrical insulating member arranged to prevent any contact between the bearing and said neutral-point conductor end, this insulating member extending at least partially through the bearing opening and being at least partially outside the bearing.

According to one aspect of the invention, the electrical insulating member is advantageously arranged to be at least partially supported on an outer surface of the bearing. In an exemplary implementation of the invention, the electrical insulating member has a substantially annular shape. The electrical insulating member may have a closed annular shape or, alternatively, interrupted. Preferably, the insulating member comprises at least one tongue extending at least partially through the opening of the bearing and arranged to prevent any contact between the bearing and said neutral point conductor end. Preferably, the insulating member comprises a plurality of tabs advantageously distributed substantially uniformly along an arc of a circle on the insulating member.

In an exemplary implementation of the invention, the insulating member comprises as many insulating tabs as neutral points of the coil, this number being for example equal to seven. If necessary, the insulation tab comprises a substantially semi-cylindrical base connecting to a flat face of the insulating member, preferably inclined with respect to this planar face forming an advantageously non-zero angle. The insulating member may comprise at least one notch arranged to receive a phase output conductor end, this notch being in particular open on an outer periphery of the insulating member.

The insulating member is for example made of plastic. Advantageously, the insulating member is arranged to close at least partially, in particular with the aid of a radially projecting portion, at least one opening, in particular a plurality of openings, of the bearing. The insulating member may, if necessary, completely plug at least one opening of the bearing.

This can make it possible to limit axial air exchanges, in particular by recirculation, in the machine at an electronic unit fixed on the bearing, in order to lower the temperature of the electronic unit and thus to increase the performance of the the machine.

In an exemplary implementation of the invention, the insulating member comprises at least one detent tab arranged to allow the attachment of this insulating member on the bearing. Where appropriate, the machine may comprise at least one electronic unit equipped with a heat sink provided with fins, and the insulating member comprises at least one groove for engaging at least partially a fin of the heat sink. heat. This can make the product mechanically compatible with different types of fasteners available on bearings. For example, the groove is formed between two elastically deformable tabs, these tabs extending in particular on an outer face of the insulating member. In an exemplary implementation of the invention, the insulating member comprises a flange, in particular substantially cylindrical, extending substantially in the extension of a cylindrical wall of a hood of the machine. The invention also relates to a rotating electrical machine, in particular an alternator or an alternator-starter, comprising: a stator comprising an electric winding, this winding comprising a plurality of electrical conductors and at least one of these conductors comprising an end forming an electrical neutral point of the winding, - an electrical insulating member arranged to cover the neutral point forming end of the conductor, this member being in particular arranged in an interior space defined between bearings of the machine. The insulating member may comprise at least one cap, in particular formed by a recess in an insulating strip for example substantially in the shape of an arc of a circle, to cover the end of conductor forming a neutral point.

This recess may for example have a bowl shape. Advantageously, the isolation member comprises a plurality of caps distributed over the insulating strip. In an exemplary implementation of the invention, the end of neutral-point conductor is welded to an electrically conductive bar, and the electrical insulating member caps the neutral-point conductor end and a portion at the end. less than the busbar. For example, the stator winding comprises a plurality of pin-type conductors.

This stator winding can be star type. In an exemplary implementation of the invention, the stator winding is of heptaphased type, with in particular seven neutral points. The invention also relates to an electrical insulating member of a machine as defined above.

The invention also relates to a rotating electrical machine, in particular an alternator or an alternator-starter, comprising: a stator comprising an electric winding, this winding comprising a plurality of electrical conductors and at least one of these conductors comprising an end forming an electrical neutral point of the winding, - an insulating cap arranged to cover the end of neutral-point conductor, this cap being arranged to be put in place from the outside of bearings of the machine, through an opening of the one of these levels. In an exemplary implementation of the invention, the neutral-point conductor ends are each capped by an individual cap. The invention also relates to a method for manufacturing a rotary electrical machine as defined above, comprising the following step: - cap the end of the neutral point conductor with an electrically insulating cap placed from the outside bearings of the machine, through an opening of one of these bearings.

The object of the invention is, according to another of its aspects, a rotating electrical machine, notably an alternator or an alternator-starter for a motor vehicle, comprising: a stator comprising an electric winding, this winding comprising a plurality of electrical conductors and at least two of these conductors each comprising an end forming, for example, an electric neutral point of the winding, - an electrical connection member arranged to electrically connect two points, in particular two neutral points, of the stator winding, this electrical connection member; comprising at least one partially embedded electrically conductive element, in particular by overmoulding, in an electrically insulating material. Thanks to the invention, the electrical connection between the two points of the winding can be relatively robust.

In an exemplary implementation of the invention, the connection member comprises a ring made of electrically insulating material. Where appropriate, the electrical connection member comprises a plurality of conductive elements, each substantially having a U-shape, at least two of these adjacent conductive elements forming a space for the insertion of a conductor end forming a point neutral electric winding. This can make a weld of the conductive elements easily accessible. Advantageously, the conductor end forming an electrical neutral point of the winding is soldered, in particular by resistance brazing or by electric arcs or by soldering or by laser, to the adjacent conductive elements of the electrical connection member. Preferably, the conductive elements of the electrical connection member each comprise at least one chamfer facing the stator winding arranged to facilitate the insertion of a conductor end forming an electrical neutral point of the winding.

This may make it possible to form a guide for insertion of the conductor, for example cone-shaped. In an exemplary implementation of the invention, the electrical connection member comprises at least one slot, opening in particular around an inner periphery of this connection member, this slot being arranged to at least partially receive the conductor end. forming an electrical neutral point of the winding. If desired, the connecting member has a substantially circular inner periphery, and said slot forms with a diameter of the connecting member a non-zero angle. This inclination of the slot may be advantageous especially for the passage of a solder tool of the winding conductor. Alternatively, the connecting member has a substantially circular inner periphery, and said slot extends parallel to a diameter of the connecting member.

In an exemplary implementation of the invention, the electrical connection member comprises at least one orifice, in particular made in an electrically insulating ring, arranged to allow the passage of an electrical conductor portion of the stator winding, this portion of conductor advantageously forming an input or a phase output of the stator winding. This may be advantageous for stiffening the foot of the portion of conductor passing through the orifice. If desired, the conductive elements of the connection member are made of copper. Advantageously, the conductive elements of the connection member are embedded in the plastic over a major part of their length. The electrical connection member may for example be placed on a top of a bun of the stator winding. The invention can thus allow a satisfactory thermal insulation. Preferably the connection member at least partially blocks an opening of a bearing of the machine, in particular to limit axial air exchange between the inside of the bearings and the rear of an electronic unit of the machine. The invention also relates to an electrical connection member, in particular for a machine as defined above, this electrical connection member being advantageously arranged to make it possible to electrically connect two neutral points of a stator winding, this electrical connection member comprising at least one at least one electrically conductive element partially embedded, in particular by overmolding, in an electrically insulating material.

The subject of the invention is also a rotating electrical machine, in particular an alternator or a starter-alternator for a motor vehicle, comprising: a stator comprising an electric winding, this winding comprising a plurality of electrical conductors and at least two of these conductors comprising each end forming an electrical neutral point of the winding, - an electrical connection member arranged to electrically connect two neutral points of the stator winding, the electrical connection member comprising at least one electrically conductive strip, the conductive strip being bare, by being free of electrically insulating coating or being enamelled and locally bare. Advantageously, the conductive strip comprises at least one U-shaped portion enabling contact with an end forming an electrical neutral point of the winding.

The invention will be better understood on reading the following detailed description of examples of non-limiting embodiments of the invention, and on examining the appended drawing, in which: FIG. schematically and partially, in longitudinal section, an alternator according to an exemplary implementation of the invention, - Figure 2 illustrates, schematically and partially, the machine of Figure 1, with an electrical insulating member according to a embodiment of the invention, FIG. 3 is a schematic and partially insulated representation of the insulating member of FIG. 2, FIG. 4 is a diagrammatic and partial sectional view of FIG. IV, the isolating member of FIG. 3; FIG. 5 is a diagrammatic and partial perspective view of a detail of the insulating member of FIG. 2, cooperating with a fin of a heat sink. - Figure 6 shows, schematically and partially, an electrical connection member placed on a stator winding according to an exemplary implementation of the invention, - Figures 7 and 8 show, schematically and partially, in isolation, according to two different views 6 and 10 are diagrammatic and partial views, respectively in section along IX-IX and XX, of the connecting member of FIGS. 7 and 8, FIG. illustrates schematically and partially the use of a welding tool throughout Figure 6, - Figure 12 shows schematically and partially an electrical connection member according to another embodiment of the invention, and - the Figures 13 and 14 show, schematically and partially, two other examples of implementation of the invention for a connection member. In the remainder of the description, the arrows "A" and "R" of FIG. 1 respectively indicate axial and radial directions.

FIG. 1 shows a polyphase rotary electric machine 1 forming, in the present embodiment of the invention, an alternator for a motor vehicle. Of course, the electric machine 1 may, if desired, be reversible and form an alternator-starter that can operate in electric motor mode to start the combustion engine of the vehicle and alternator mode to produce electrical energy. This machine 1 comprises a housing 10 and, inside thereof, a rotor 12 rotatably connected to a rotary shaft 14 of X axis, called the rotor shaft, and a stator 16 which surrounds the rotor 12. The stator 16 comprises a body 17 formed of a sheet metal package provided with notches for mounting a stator winding 18 forming buns 30 and 31 on either side of the stator body 17. The rotor 12 comprises two pole wheels 20 and 22, each provided with a transverse flange 24 on the periphery of which are connected a plurality of claws 26 extending substantially in the axial direction A. The claws 26 of a pole wheel form with the claws 26 of the other polar wheel interpolar spaces arranged to each receive a magnet structure, not shown. An excitation coil 34 is placed between the flanges 24 of the pole wheels 20 and 22. Each pole wheel 20; 22 has a bore forming an inner passage 38 for receiving the shaft 14.

The pole wheels 20 and 22 are made for example of steel. The shaft 14 carries at its front end a pulley 40 belonging to a device for transmitting motion through at least one belt (not shown) between the alternator 1 and the combustion engine of the motor vehicle, and its rear end of the slip rings 42 connected by wire links (not shown) to the excitation coil 34 of the rotor 12.

Brushes of a brush holder 44 shown very schematically are arranged to rub on the slip rings 42, to supply the coil 34 with electrical current. When the shaft 14 is rotating and the excitation winding 34 is activated by a power supply, the inductor rotor 12 creates an alternating induced current in the stator 16. The casing 10 comprises, in the example under consideration, two parts, to namely a front bearing 46 and a rear bearing 48 carrying the brush holder 44.

The bearings 46 and 48 each carry a ball bearing respectively 50 and 52 for the rotational mounting of the shaft 14. As can be seen in Figure 2 in particular, the bearings 46 and 48 are provided with radially inner openings 45 and 49 radially outer for particular allow the passage of cooling air within the machine. The rear bearing 48 is capped by a protective cover 61. The latter comprises a cylindrical lateral skirt 62 extending along the axis X. The rotor 12 carries, in the example described, at least at one of its ends. axial a fan to ensure air circulation. A first ventilation element 54 is for example provided on the front transverse face of the rotor 12 and a second ventilation element 56 is provided on the rear face of the rotor 12. Each ventilation element 54 and 56 is provided with a plurality of blades 58 and 60. In the example described, the winding 18 of the stator 16 is of heptaphased type, namely has seven phases, with seven neutral points. Alternatively, the coil 18 may have a different number of phases, for example three, five or six.

The coil 18 is formed, in the example described, by a plurality of pin-type conductors.

Alternatively, the coil 18 may be formed by a plurality of electrically conductive wires. The neutral points of the winding 18 are formed on the ends of the conductors of the winding 18.

According to a first aspect of the invention, as illustrated in FIGS. 2 to 5, an electrical insulating member 70 is provided to prevent possible electrical contact between the rear bearing 48 and neutral-point conductor ends. This insulating member 70 extends partially through radially outer openings 49 of the rear bearing 48. This electrical insulating member 70 is placed in abutment on an outer surface 71 of the rear bearing 48. As can be seen in FIGS. FIGS. 2 and 3 in particular, the electrical insulating member 70 has a substantially closed annular shape.

In the example described (see FIG. 3 in particular), the insulating member 70 comprises a plurality of tabs 72 extending through openings 49 of the bearing 48 and arranged to prevent any contact between the bearing 48 and the ends. conductor forming neutral points. These tongues 72 are distributed in a substantially regular manner along an arc of a circle on the insulating member 70. The insulating member 70 has as many isolation tabs 72 as neutral points of the winding, this number being equal to seven in the example described. Each insulating tongue 72 comprises a substantially semicylindrical base 74 connected to a flat face 75 of the insulating member 70, inclined relative to this flat face 75 at a non-zero angle. This enveloping shape of each tongue 72 allows insulation about 180 ° around the conductor forming a neutral point. The insulating member 70 comprises a plurality of notches 76 arranged to each receive a phase output conductor end, each notch 76 being open on an outer periphery 77 of the insulating member 70.

The insulating member 70 is for example made of plastic, by injection. In addition, the insulating member 70 is arranged to plug, by means of a radially projecting portion 79, openings 49 of the rear bearing 48, as can be seen in FIG. 70 comprises a plurality of latching tabs 80 arranged to allow snap-fastening of this insulating member 70 on the bearing 48, as illustrated in FIG. 4. When the machine 1 comprises an electronic unit equipped with a dissipator of heat 81 provided with fins 82 as shown in Figure 5, the insulating member 70 may comprise a groove 84 for partially engaging a fin 82 of the heat sink 81. The groove 84 is formed between two tabs elastically deformable 85, these lugs 85 extending on an outer face 86 of the insulating member 70.

In an exemplary implementation not illustrated, the insulating member 70 may comprise a cylindrical rim extending substantially in the extension of the skirt 62 of the cover 61 of the machine 1. In an exemplary implementation of the In the invention, the insulator 70 may have protuberances extending axially through one or more openings 49, even if these openings do not enclose the neutral-point conductor ends. These protuberances may be substantially of the same shape as these openings 49 and their thickness may be chosen substantially equal to the thickness of the plateau of the bearing. These protuberances preferably do not exceed the outer diameter of the insulating member 70. There is shown in Figures 6 to 11 another example of implementation of the invention. In this example, an electrical connection member 90 is provided to electrically connect several neutral points of the winding 18 of the stator 16.

This member 90 also allows insulation of the stator winding, as well as a closure of the openings of the bearing to limit axial air flows. This electrical connection member 90 comprises a plurality of electrically conductive elements 91 partially embedded by overmoulding in an electrically insulating material 92, as illustrated in FIGS. 8 and 9 in particular. The connection member 90 comprises a ring made of electrically insulating material 92. Each conductive element 91 has a substantially U-shape.

Each pair of two of these adjacent conductive elements 91 forms, between end branches 94 of the U, a space 93 for the insertion of a conductor end 95 forming an electrical neutral point of the winding 18, as can be seen in particular in FIG. see FIG. 11. The end 95 of conductor forming an electrical neutral point of the winding is soldered, in particular by resistance brazing or by electric arcs or by soldering or by laser, to the adjacent conductive elements 91 of the body 70. As shown in FIG. 11, the welding is carried out for example using a tool 96 provided with two electrodes 97.

The conductive elements 91 of the electrical connection member 90 each comprise a chamfer 99 facing the stator winding 18 arranged to facilitate the insertion of a conductor end 95 forming an electrical neutral point of the winding 18 (see FIG. ). The electrical connection member 90 comprises a plurality of slots 100 opening on an inner periphery 101 of this connection member 90 (see in particular Figures 7 and 8). These slots 100 have for example a substantially rectangular shape. Each slot 100 is arranged to at least partially receive the conductor end 95 forming an electrical neutral point of the winding 18.

The inner periphery 101 is substantially circular, and each slot 100 forms with a diameter of the connection member 90 a non-zero angle A (see Figure 8 for example). The angle A is for example chosen between 10 ° and 90 °, being in particular close to 45 °. This inclination A of the slot 100 is advantageous for the passage of the welding tool 96. In a variant, as illustrated in FIG. 12, each slot 100 can extend parallel to a diameter of the connection member 90.

The electrical connection member 90 comprises a plurality of orifices 104, of rectangular shape, made in the electrically insulating ring 92, and arranged to allow the passage of a portion 105 of electrical conductor of the stator winding 18. 105 of the conductor forms an input or a phase output of the stator winding. This may be advantageous for stiffening the foot of the portion 105 of conductor passing through the orifice 104. The conductive elements 91 of the connection member 90 are made of copper, for example.

As illustrated in FIG. 11, the electrical connection member 90 is placed on the top of the bun 30 of the stator winding 18. An electrical insulating member 110 is provided for capping the neutral conductor ends 95 inserted between the conductors 91, as illustrated in FIG. 6.

This insulating member 110 is disposed in an interior space defined between bearings 46 and 48 of the machine 1. The insulating member 110 comprises a plurality of caps 111 each formed by a recess, in the form of a bowl, in a insulating strip 112 substantially in the shape of an arc.

This allows protection of the welded neutral points of the winding, as well as a limitation of the axial air flows.

In the example described, the insulating member 110 is fixed on the connection member 90 by means of pins 114. FIGS. 13 and 14 show two examples of connection members according to the invention. .

In the example of Figure 13, the electrical connection member 115 is arranged to allow to electrically connect all the neutral points of the winding 18 of the stator. This electrical connection member 115 comprises a single electrically conductive strip 116, this conductive strip being bare, being devoid of electrically insulating coating. The conductive strip 116 has a plurality of U-shaped portions 117 each making it possible to bring the end-piece 95 into contact with an end 95 forming an electrical neutral point of the winding 18. In a variant of the invention illustrated in FIG. 115 comprises two separate conductor strips 116 each provided for three connections only. 20

Claims (10)

Revendications1. Rotating electrical machine (1), in particular an alternator or an alternator-starter for a motor vehicle, comprising: - a stator (16) comprising an electric winding (18), this winding comprising a plurality of electrical conductors and at least two of these conductors each comprising an end (95) forming an electrical neutral point of the winding, - an electrical connection member (90) arranged to electrically connect two neutral points of the stator winding, this electrical connection member comprising at least one electrically conductive element (91) partially embedded, in particular by overmolding, in an electrically insulating material (92). 2. Machine according to the preceding claim, characterized in that the connecting member comprises a ring (92) made of the electrically insulating material. 3. Machine according to one of the preceding claims, characterized in that the electrical connection member comprises a plurality of conductive elements (91), each substantially having a U-shape, at least two of these adjacent conductive elements forming a space (93) for insertion of a conductor end forming an electrical neutral point of the winding. 4. Machine according to the preceding claim, characterized in that the end (95) of conductor forming an electrical neutral point of the winding is welded, in particular by resistance braking or by electric arcs or by soldering or by laser, adjacent conductive elements of the electrical connection member. 5. Machine according to any one of the preceding claims, characterized in that the electrical connection member (90) comprises at least one slot (100), opening in particular on an inner periphery (101) of this connection member, this slot being arranged to at least partially receive the conductor end forming an electrical neutral point of the winding. 6. Machine according to the preceding claim, the connecting member having a substantially circular inner periphery, characterized in that said slot (100) forms with a diameter of the connecting member a non-zero angle (A). 7. Machine according to any one of the preceding claims, characterized in that the electrical connection member comprises at least one orifice (104), in particular made in an electrically insulating ring, arranged to allow the passage of a portion of electrical conductor of the stator winding, this conductor portion advantageously forming an input or a phase output of the stator winding. 8. Electrical connection member (90) in particular for a machine according to any one of the preceding claims, this electrical connection member being advantageously arranged to allow to electrically connect two neutral points of a stator winding, the electrical connection member. comprising at least one partially embedded electrically conductive element, in particular by overmoulding, in an electrically insulating material. 9. A rotating electrical machine, in particular an alternator or an alternator-starter for a motor vehicle, comprising: a stator comprising an electric winding, this winding comprising a plurality of electrical conductors and at least two of these conductors each comprising a end forming a point; electrical neutral winding, - an electrical connection member (115) arranged to allow to electrically connect two neutral points of the stator winding, the electrical connection member having at least one electrically conductive strip (116), the conductive strip being bare. 10. Machine according to the preceding claim, characterized in that the conductive strip (116) comprises at least one portion (117) in U for contacting with an end forming an electrical neutral point of the winding.