FR3053542A1 - DOUBLE EXCITATION ROTOR FOR ROTATING ELECTRICAL MACHINE - Google Patents

Abstract

The invention relates mainly to a rotor (12) of rotating electrical machine, in particular for a motor vehicle, comprising: - two pole wheels (24, 25) each comprising a flange (28) provided at its outer periphery with claws (29), said claws (29) of said pole wheels (24, 25) being interleaved with each other; - a core (30) interposed axially between said flanges (28) of said pole wheels (24, 25), and - a first winding excitation device (31) wound around said core (30), characterized in that said rotor (12) further comprises a second excitation winding (32) extending in part between said claws (29) of said pole wheels ( 24, 25).

Description

Holder (s): VALEO ELECTRIC EQUIPEMENTS MOTOR Simplified joint-stock company.

Extension request (s)

Agent (s): VALEO EQUIPEMENTS ELECTRIQUES MOTOR Simplified joint-stock company.

ROTOR WITH DOUBLE DRIVE FOR ROTATING ELECTRIC MACHINE.

FR 3 053 542 - A1 fü /) The invention relates mainly to a rotor (12) of a rotating electrical machine, in particular for a motor vehicle, comprising:

two pole wheels (24, 25) each comprising a flange (28) provided at its outer periphery with claws (29), said claws (29) of said pole wheels (24, 25) being nested with respect to each other,

a core (30) interposed axially between said flanges (28) of said pole wheels (24, 25), and

- a first excitation winding (31) wound around said core (30), characterized in that said rotor (12) further comprises a second excitation winding (32) extending partly between said claws (29) said pole wheels (24, 25).

DOUBLE DRIVE ROTOR FOR ROTATING ELECTRIC MACHINE

The present invention relates to a double excitation rotor for a rotary electrical machine. The invention finds a particularly advantageous, but not exclusive, application in the field of alternators for motor vehicles capable of transforming mechanical energy into electrical energy and which may be reversible.

Reversible alternators, called alternator-starters, make it possible to transform electrical energy into mechanical energy, in particular to start the engine of the vehicle. The invention can also be implemented with an electric motor.

In a manner known per se, an alternator comprises a casing and, inside thereof, a claw rotor, integral in rotation with a shaft, and a stator which surrounds the rotor with the presence of an air gap.

The stator comprises a body constituted by a stack of thin sheets forming a crown, the inner face of which is provided with notches open towards the inside to receive phase windings. These windings pass through the notches in the stator body and form buns protruding from either side of the stator body. The phase windings are obtained for example from a continuous wire covered with enamel or from conductive elements in the form of pins connected together by welding. These windings are polyphase windings whose ends are connected to an electronic power module comprising in particular a rectifier bridge.

Furthermore, the rotor comprises two pole wheels each having a transverse orientation flange provided at its outer periphery with claws of axial orientation. The claws of the pole wheels are nested relative to each other. A cylindrical core is interposed axially between the flanges of the wheels. This core carries at its outer periphery an excitation winding of the rotor.

The invention aims to provide an improved rotor configuration. To this end, the subject of the invention is a rotor of a rotating electric machine, in particular for a motor vehicle, comprising:

two pole wheels each comprising a flange provided with claws at its outer periphery, said claws of said pole wheels being nested relative to each other,

a core axially interposed between said flanges of said pole wheels, and

- A first excitation winding wound around said core, characterized in that said rotor further comprises a second excitation winding extending partly between said claws of said pole wheels.

The invention thus makes it possible, thanks to the integration of a second excitation winding, to improve the performance of the machine or to reduce its size at iso-performance. The invention also makes it possible to reduce the magnetic noise, as well as the manufacturing cost compared to machines provided with permanent magnets.

According to one embodiment, said second excitation winding comprises a plurality of main portions positioned between the lateral faces of two adjacent claws and a plurality of connecting portions disposed at the ends of said claws, each connecting portion connecting two adjacent main portions.

According to one embodiment, said second excitation winding is formed by a single wire.

According to one embodiment, said second excitation winding is formed by a plurality of wires.

According to one embodiment, the plurality of wires is contained in a housing.

According to one embodiment, the plurality of wires is coated in a layer of bonding material.

According to one embodiment, each claw has at its outer periphery two lips for radially retaining said second excitation winding.

According to one embodiment, said rotor comprises laminettes.

According to one embodiment, each strip is placed between two consecutive claws and kept wedged between two lips of two adjacent claws and the wires of the second excitation winding.

According to one embodiment, the faces of two adjacent claws facing each other define a housing of trapezoidal shape.

According to one embodiment, said rotor further comprises at least one magnet positioned between two adjacent claws.

According to another aspect, the invention relates to a rotary electrical machine, in particular for a motor vehicle, characterized in that it comprises a rotor as defined above.

According to one embodiment, said first excitation winding and said second excitation winding are electrically connected in parallel with one another.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given only by way of illustration but in no way limit the invention.

Figure 1 is a longitudinal sectional view of an alternator according to the present invention;

Figure 2 is a perspective view in partial section of the rotor according to the invention showing the layout of the second rotor excitation winding;

Figure 3 is a schematic representation illustrating the direction of the magnetic field in the claws of the rotor generated by the second excitation winding;

Figure 4 is a schematic cross-sectional view of the rotor provided with a second excitation winding formed by several wires positioned inside a housing;

FIG. 5a is a partial cross-sectional view of the rotor illustrating the production of lips formed in the claws for retaining the second excitation winding;

Figure 5b is a partial cross-sectional view of the rotor 5 illustrating an alternative embodiment using laminates;

Figure 6 is a partial cross-sectional view of the rotor illustrating an inter-claw space of trapezoidal shape to ensure retention of the second excitation winding;

FIG. 7 is an electrical diagram of the assembly of the phases and of the rotor excitation windings of the electric machine.

Identical, similar, or analogous elements keep the same reference from one figure to another.

FIG. 1 shows a compact, multi-phase alternator 10, in particular for a motor vehicle. The alternator 10 is able to transform mechanical energy into electrical energy and may be reversible. Such a reversible alternator, called an alternator-starter, makes it possible to transform electrical energy into mechanical energy in particular for starting the thermal engine of the vehicle.

This alternator 10 comprises a casing 11 and, inside thereof, a claw rotor 12 mounted on a shaft 13, and a stator 16, which surrounds the rotor 12 with the presence of an air gap between the outer periphery of the rotor 12 and the internal periphery of the stator 16. The axis X along which the shaft 13 extends forms the axis of rotation of the rotor 12.

The casing 11 has front 17 and rear 18 bearings carrying the stator 16. The bearings 17, 18 are hollow in shape and each carry a ball bearing centrally for the rotational mounting of the shaft 13.

More specifically, the rotor 12 comprises two pole wheels 24, 25 each having a flange 28 of transverse orientation provided at its outer periphery with claws 29 for example of trapezoidal shape and axial orientation. The claws 29 of one wheel 24, 25 are directed axially towards the flange 28 of the other wheel. The claws 29 of a pole wheel 24, 25 penetrate into a space existing between two claws 29 adjacent to the other pole wheel, so that the claws 29 of the pole wheels 24, 25 are nested relative to each other.

A cylindrical core 30 is interposed axially between the flanges 28 of the wheels 24, 25. In this case, the core 30 consists of two half-cores each belonging to one of the flanges 28.

A first excitation winding 31 is wound around the external periphery of the core 30. An insulating element can be inserted radially between the core 30 and the winding 31. The excitation winding 31 comprises a winding having a plurality of turns formed preferably from a single continuous wire. In FIG. 2, the schematic representation of the winding 31 in the form of a strip has been made to facilitate understanding of the figure.

In addition, a second excitation winding 32 extends partly between the claws 29 of the pole wheels 24, 25. As is clearly visible in FIG. 2, the second excitation winding 32, of generally annular shape, comprises a plurality of main portions 33 positioned between lateral faces 34 of two adjacent claws 29 and a plurality of connecting portions 36 disposed at the ends of the claws 29.

Each connecting portion 36 connects two adjacent main portions 33. The main portions 33 follow the inclination of the lateral faces 34 of the claws 29 with respect to the axis X, while the connecting portions 36 extend in a substantially circumferential direction. The second excitation winding 32 thus surrounds the first excitation winding 31.

As can be seen in FIG. 3, for a current flowing inside the second excitation winding 32 in the direction indicated by the arrows F1, the magnetic field penetrates inside the claws 29 of a pole wheel 24 (see arrow F2) and leaves the claws 29 of the other pole wheel 25 (see arrow F3).

In the embodiment of FIG. 2, the second excitation winding 32 is formed by a single wire 37.

In the embodiment of FIGS. 4, 5a, 5b, and 6, the second excitation winding 32 is formed by a plurality of wires 37.

As shown in Figure 4, the plurality of son 37 may be contained in a housing 42 ensuring its retention. The housing 42 has a shape corresponding to that of the excitation winding 32. In fact, the housing 42 has hollow parts extending between the lateral faces 34 of two adjacent claws and containing the main portions 33 of the winding 32, thus only hollow parts disposed at the ends of the claws 29 and containing the connecting portions 36 of the winding 32.

In order to link the wires 37 of the winding 32 together, the plurality of wires 37 may be coated in a layer of bonding material 44, as shown in FIGS. 5a, 5b and 6. The layer 44 may also have a function of electrical insulator. The layer 44 may for example be made of a silicone-based material in order to dissipate by conduction the heat generated by the winding 32. The layer 44 may if necessary be loaded with additives promoting thermal dissipation. The layer 44 covers all of the wires 37 of the second excitation winding 32, so that the wires 37 of the winding 32 are completely embedded in the bonding material.

As illustrated by Figures 5a and 5b, each claw 29 may have two lips 45 at its outer periphery. These lips 45 extend circumferentially on either side of each claw 29. These lips 45 make it possible to radially retain the winding 32 subjected to the centrifugal force during the high speed rotation of the rotor 12.

According to a particular embodiment shown in Figure 5b, the strips 48 are each disposed between two claws 29 consecutive. Each strip 48 is held wedged between the lips 45 of two adjacent claws 29 and the wires 37 of the second winding 32. Each strip 48 takes the form of a wafer made for example from a material based on glass fibers embedded in a material pre-impregnated plastic. The strip 48 is flat rectangular and has the same dimensions and the same shape as the main portions 33 of the second coil 32 which it covers. A layer of adhesive may be interposed between the second coil 32 and the laminates 48.

Alternatively, in the embodiment of FIG. 6, the lateral faces 34 of two adjacent claws 29 opposite one another define a housing 49 of trapezoidal shape. The section of the housing 49 is such that it decreases when one moves from the internal face towards the external face of the claws 29 in order to ensure the radial retention of the wires 37 of the second winding 32. The wires 37 may possibly be coated with the layer of bonding material 44.

It will also be possible to provide magnets 54 positioned between two adjacent claws 29 of the rotor, as shown in FIG. 5b. This further improves the magnetic performance of the rotating electrical machine.

As shown in FIG. 1, the shaft 13 may be force-fitted into the central bore of the pole wheels 24, 25. On the side of its front end, the shaft 13 may include a threaded part for fixing the 'A pulley 35. The pulley 35 belongs to a movement transmission device with at least one belt between the alternator 10 and the engine of the motor vehicle.

The rear bearing 18 carries a brush holder 38 provided with brushes 39 intended to rub against rings 40 of a collector 41 to supply the winding of the rotor 12.

Furthermore, the stator 16 comprises a body 43 in the form of a packet of sheets provided with notches equipped with insulating notches for mounting the phases of the stator 16. Each phase comprises at least one phase winding passing through the notches of the stator body 43 and forms, with all the phases, a front bun 46 and a rear bun 47 on either side of the stator body 43.

The phase windings are obtained for example from a continuous wire covered with enamel or from conductive elements in the form of pins electrically connected to each other for example by welding. The phase windings are electrically connected to an electronic power module. This module notably includes a rectifier bridge 52.

FIG. 7 represents the electrical diagram of a three-phase rotary electrical machine, for example with six poles. The phase windings U, V, W, in this case coupled in a triangle, are each connected to a bridge arm 51 corresponding to a rectifier bridge 52. Each bridge arm 51 comprises two rectifier elements 55, such as diodes or to MOSFET type transistors. The rectifier bridge 52 is electrically connected to the terminals of the battery 53 of the motor vehicle.

The two excitation windings 31, 32 of the rotor are electrically connected in parallel with one another. The windings 31, 32 are supplied by the vehicle battery 53.

Alternatively, the U, V, W phase windings can be star-coupled. As a variant, the two excitation windings 31, 32 of the rotor are electrically connected in series with one another.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention from which one would not depart by replacing the various elements with any other equivalent.

Furthermore, the various features, variants, and / or embodiments of the present invention can be combined with one another in various combinations, insofar as they are not incompatible or mutually exclusive of one another.

Claims (13)

1. Rotor (12) of a rotary electrical machine (10), in particular for a motor vehicle, comprising: two pole wheels (24, 25) each comprising a flange (28) 5 provided at its outer periphery with claws (29), said claws (29) of said pole wheels (24, 25) being nested relative to each other, a core (30) interposed axially between said flanges (28) of said pole wheels (24, 25), and - A first excitation winding (31) wound around said core (30), characterized in that said rotor (12) further comprises a second excitation winding (32) extending partly between said claws (29 ) of said pole wheels (24, 25). 2. Rotor according to claim 1, characterized in that said second excitation winding (32) comprises a plurality of main portions (33) 15 positioned between lateral faces (34) of two adjacent claws (29) and a plurality of connecting portions (36) arranged at the ends of said claws (29), each connecting portion (36) connecting two main main portions (33) adjacent . 3. Rotor according to claim 1 or 2, characterized in that said 20 second excitation winding (32) is formed by a single wire (37). 4. Rotor according to claim 1 or 2, characterized in that said second excitation winding (32) is formed by a plurality of wires (37). 5. Rotor according to claim 4, characterized in that the plurality of wires (37) is contained in a housing (42). 25 6. Rotor according to claim 4, characterized in that the plurality of wires (37) is coated in a layer of bonding material (44). 7. Rotor according to any one of claims 1 to 6, characterized in that each claw (29) has at its outer periphery two lips (45) for radial retention of said second excitation winding (32). 8. Rotor according to any one of claims 1 to 7, characterized in that it comprises laminettes (48). 9. Rotor according to claims 7 and 8, characterized in that each strip (48) is arranged between two claws (29) consecutive and maintained 5 wedged between two lips (45) of two adjacent claws (29) and the wires (37) of the second excitation winding (32). 10. Rotor according to any one of claims 1 to 9, characterized in that the faces (34) of two claws (29) adjacent opposite each other define a housing (49) of trapezoidal shape. îo 11. Rotor according to any one of claims 1 to 10, characterized in that it further comprises at least one magnet (54) positioned between two adjacent claws (29). 12. Rotating electric machine (10), in particular for a motor vehicle, characterized in that it comprises a rotor (12) as defined 15 according to any one of the preceding claims. 13. Rotating electric machine according to claim 12, characterized in that said first excitation winding (31) and said second excitation winding (32) are electrically connected in parallel with each other. 2/4 3/4