WO2018146391A1

WO2018146391A1 - Rotor for a rotating electrical machine provided with balancing holes

Info

Publication number: WO2018146391A1
Application number: PCT/FR2018/050065
Authority: WO
Inventors: Khadija El Baraka; Christophe Dugue
Original assignee: Valeo Equipements Electriques Moteur
Priority date: 2017-02-09
Filing date: 2018-01-11
Publication date: 2018-08-16
Also published as: FR3062756B1; FR3062756A1

Abstract

The invention mainly relates to a rotor (12) of a rotating electrical machine for a motor vehicle, characterised in that it comprises: - a body (23) formed by a bundle of magnetic sheets, - a plurality of permanent magnets housed in cavities of the body, - two flanges (27, 28) arranged at each axial end of the body , - the body (23) and the flanges (27, 28) each comprising a central through-opening (31) for the passage of a shaft (13), and - at least one balancing blind hole (38) produced in the body (23) in order to achieve a balancing of the rotor (12).

Description

ROTOR OF ROTATING ELECTRIC MACHINE WITH HOLES

BALANCING

The present invention relates to a rotary electric machine rotor with balancing holes. The invention finds a particularly advantageous, but not exclusive, application with high power reversible electrical machines that can operate in alternator mode and in motor mode coupled with a host element, such as a gearbox.

In known manner, the rotating electrical machines comprise a stator and a rotor secured to a shaft. The rotor may be integral with a driving shaft and / or driven and may belong to a rotating electrical machine in the form of an alternator, an electric motor, or a reversible machine that can operate in both modes.

The stator is mounted in a housing configured to rotate the shaft on bearings by bearings. The rotor comprises a body formed by a stack of sheets of sheet metal held in pack form by means of a suitable fastening system.

The stator comprises a body constituted by a stack of thin sheets forming a ring, the inner face of which is provided with notches open towards the inside to receive phase windings. These windings pass through the notches of the stator body and form buns protruding from both sides 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 connected in star or delta whose outputs are connected to an inverter also operating as a bridge rectifier.

Furthermore, the rotor may comprise a body formed by a bundle of sheets made of a magnetic material, in particular steel, as well as poles formed by a plurality of permanent magnets housed in cavities. from the body. In addition, two flanges are arranged at each axial end of the body to ensure the retention of the magnets.

The balancing is generally performed by the flanges which locally comprise extra thicknesses, which causes an increase in the axial size and the weight of the electric machine.

The present invention aims to effectively remedy this disadvantage by proposing a rotating electric machine rotor for a motor vehicle, characterized in that it comprises:

a body formed by a bundle of magnetic sheets,

a plurality of permanent magnets housed in cavities of the body,

two flanges arranged at each axial end of the body,

- The body and the flanges each having a central through opening for the passage of a tree, and

at least one blind balancing hole made in the body for balancing the rotor.

The invention thus makes it possible, by making blind holes in the rotor body, to reduce the axial length as well as the weight of the rotor by avoiding the use of flanges provided with extra thicknesses.

In one embodiment, the balancing hole opens on an axial end face of the body.

According to one embodiment, at least one flange comprises means for guiding a tool for producing the balancing hole.

According to one embodiment, the flange comprises at least one guide through hole coaxial with the balancing hole. In one embodiment, the flanges comprise an indexing means to be indexed angularly relative to the rotor body. This ensures that the guide holes are in the correct locations to achieve the corresponding balancing holes without damaging the magnets.

According to one embodiment, the indexing means is a fixing hole allowing the passage of a fixing member. In one embodiment, the guide hole has an axis intersecting the rotor body outside the cavities when the flange and the rotor body are indexed angularly relative to each other. This will prevent damage to a permanent magnet when drilling the balancing hole. In one embodiment, said rotor has a plurality of guide holes and corresponding counterbalance holes.

In one embodiment, the balancing holes are located on each axial side of the rotor body.

In one embodiment, the balancing holes on one axial side of the body are diametrically opposed to those made on the other axial side of the rotor body.

In one embodiment, the flanges comprise a plurality of guide holes, only part of which opens into a corresponding balancing hole. According to one embodiment, said rotor comprises a plurality of fasteners, each fastener passing through both the flanges and the body to hold together the flanges and sheets of the sheet package.

In one embodiment, said rotor is of flux concentration type. The permanent magnets are then implanted radially or in a V configuration inside the sheet package.

In one embodiment, the permanent magnets extend ortho-radially inside the cavities of the rotor body.

According to another aspect, the subject of the invention is a rotary electric machine for a motor vehicle, characterized in that it comprises a rotor as previously defined.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given for illustrative but not limiting of the invention. Figure 1 is a longitudinal sectional view of a rotary electric machine according to the present invention;

Figure 2 is a perspective view of the rotor according to the present invention mounted on a shaft of the rotating electrical machine without the magnet holding flanges;

Figure 3 is a perspective view of the rotor according to the present invention mounted on a shaft of the rotating electrical machine with the magnet holding flanges;

Figure 4 is a detailed perspective view of the rotor illustrating the configuration of a flange according to the present invention;

Figures 5a and 5b are perspective views respectively of the front and rear flanges of the rotor according to the present invention.

Identical, similar or similar elements retain the same reference from one figure to another. In the remainder of the description, the term "front" element, an element located on the side of the pinion carried by the machine shaft and by "rear" element an element located on the opposite side.

FIG. 1 shows a rotating electrical machine 10 comprising a polyphase stator 1 1 surrounding a rotor 12 mounted on a shaft 13 of axis X. The stator 11 surrounds the rotor 12 with the presence of an air gap between the inner periphery of the stator 1 1 and the outer periphery of the rotor 12. The stator January 1 is mounted in a housing 14 provided with a front bearing 17 and a rear bearing 18 rotatably supporting the shaft 13. For this purpose, bearings 15 are interposed between the shaft 13 and the bearings 17, 18. The bearing 15 shown in Figure 3 is associated with a target holder 21 integral with the inner ring of the bearing 15 to allow monitoring of the angular position of the rotor 12.

This electric machine 10 can be coupled, via a pinion 16, to a gearbox belonging to a motor vehicle traction chain. To ensure a rotational connection between the shaft 13 and the pinion 16, a spline assembly 22 of complementary shape may intervene between these two elements, as shown in Figures 2 and 3.

The machine 10 is able to operate in an alternator mode to supply, in particular, energy to the battery and to the on-board vehicle network, and in a motor mode, not only to start the engine of the vehicle, but also to participate in pulling the vehicle alone or in combination with the engine. The power of the machine 10 may be between 15kW and 50kW.

More specifically, the stator January 1 comprises a body 19 consisting of a bundle of sheets and a coil 20. The body 19 is formed by a stack of sheets of sheets held in package form by means of a suitable fastening system . This body 19 is provided with teeth defining two by two notches for mounting the winding 20.

The coil 20 comprises a set of phase windings passing through the notches and forming protruding buns on either side of the stator body 19. The phase windings are obtained here from shaped conductor elements. pins connected together for example by welding. These windings are, for example, three-phase windings connected in a star or in a triangle. The outputs of the phase windings are connected to an inverter which can also operate if necessary as a bridge rectifier.

Moreover, as illustrated in FIGS. 2, 3 and 4, the rotor 12 comprises a body 23 formed by a bundle of sheets made of a magnetic material, in particular steel, as well as a plurality of permanent magnets 24 housed in cavities 25 of the body 23. Two flanges 27, 28, advantageously made of non-magnetic steel, are arranged at each axial end of the body 23, as shown in FIG.

Preferably, the sheets 30 of the stack of axially stacked sheets may be glued together to facilitate the handling of the pack during transport before final assembly with the flanges 27, 28 and the shaft 13. The permanent magnets 24 may be implanted inside the cavities 25 in a V-shaped configuration (see FIG. 2) or may be implanted radially inside the pack of sheets 23, the lateral faces opposite two consecutive magnets 24 being of the same polarity. The rotor 12 is then of flux concentration type.

Alternatively, the permanent magnets 24 extend ortho-radially inside the cavities 25 of the body 23. The magnets 24 may be of rare earth or ferrite depending on the applications and the desired power of the machine 10. The rotor body 23 and the flanges 27, 28 each comprise a central opening 31 for the passage of the shaft 13. This shaft 13 comprises a section fitted into the opening of the rotor body 23 to rotate the rotor body 23 to rotate tree 13.

In addition, as can be seen in FIG. 3, the flanges 27, 28 and the rotor body 23 have through holes 34 allowing the passage of corresponding fixing members 35. The fixing holes 34 of the rotor body 23 are located in coincidence with the fixing holes 34 of the corresponding flanges 27, 28.

Each fastener 35 passes axially through both the flanges 27, 28 and the body 23 to hold together the flanges 27, 28 and the sheets 30 of the body 23.

Preferably, the fasteners 35 are rivets. The rivets 35 take the form of an elongated rod provided with a head at one of its ends. The other end of the rod can be crushed, for example by pegging after being threaded through the flange assembly 27, 28 and rotor body 23. Alternatively, the free end is threaded and the flange assembly 27, 28 and rotor body 23 is held by means of a nut screwed onto the threaded end. The fasteners 35 are made of a magnetic material or a non-magnetic material. Moreover, as can be seen in FIGS. 4, 5a, and 5b, each flange 27, 28 has a plurality of guide holes 37 passing through made in advance in the flanges 27, 28 to allow the passage of a drill-type tool, adapted to make a balancing hole 38 blind opening on an axial end face of the body 23.

In this case, the guide holes 37 are arranged in the same circumference and angularly spaced between them regularly. The guide holes 37 are made to a diameter smaller than the one in which the fixing holes 34 are made. Any other arrangement of the guide holes 37 adapted to the application could, however, be envisaged.

Depending on the balancing need, some of the guide holes 37 of the set will be used to make corresponding blind holes 38 in the rotor body 23, as shown in FIG. 4. Thus, once the balancing of the rotor 12 made, each balancing hole 38 is coaxial with the corresponding guide hole 37. In addition, on all the guide holes 37, only one part opens into a corresponding balancing hole 38, the other guide holes 37 having not been used for balancing the rotor 12.

The balancing holes 38 are located on each axial side of the rotor body 23 being diametrically opposed to those formed on the other axial side of the rotor body 23. The flanges 27, 28 also preferably comprise an indexing means 40 to be indexed angularly with respect to the rotor body 23. When the flange 27, 28 and the body 23 are angularly indexed relative to each other, the Y axes of the guide holes 37 cut the body 23 to outside the cavities 25 for receiving the magnets 24. This makes it possible to avoid damaging the permanent magnets 24 during the drilling of the balancing holes 38.

The indexing means 40 is preferably constituted by the fixing holes 34 allowing the passage of the rivets 35 for fixing the flanges 27, 28 to the rotor body 23. Indeed, when the fixing holes 34 are crossed by the corresponding fixing members, correct angular positioning of the flanges 27, 28 is ensured, avoiding interference between the balancing holes 38 and the permanent magnets 24. As shown in FIG. 5a, the front flange 27 may also comprise shapes 41 for receiving the holding springs of the permanent magnets 24.

In a variant, the means for guiding the tool for producing the balancing holes 38 may consist of marks made on an external face of the flanges 27, 28.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention which would not be overcome by replacing the different elements by any other equivalent.

In addition, the various features, variations, and / or embodiments of the present invention may be associated with each other in various combinations, to the extent that they are not incompatible or exclusive of each other.

Claims

1. Rotor (12) for a rotary electric machine (10) for a motor vehicle, characterized in that it comprises:

a body (23) formed by a bundle of magnetic sheets (30), a plurality of permanent magnets (24) housed in cavities (25) of the body (23),

two flanges (27, 28) arranged at each axial end of the body,

- the body (23) and the flanges (27, 28) each having a central opening (31) through for the passage of a shaft (13), and

- At least one blind hole (38) made in the body (23) for balancing the rotor (12).

2. Rotor according to claim 1, characterized in that the balancing hole (38) opens on an axial end face of the body (23).

3. Rotor according to claim 1 or 2, characterized in that at least one flange (27, 28) comprises a guide means (37) of a tool for producing the balancing hole (38).

4. Rotor according to claim 3, characterized in that the flange (27, 28) comprises at least one guide through hole (37) coaxial with the balancing hole (38).

5. Rotor according to any one of claims 1 to 4, characterized in that the flanges (27, 28) comprise an indexing means (40) to be indexed angularly relative to the rotor body (23).

6. Rotor according to claim 5, characterized in that the indexing means (40) is a fixing hole (34) allowing the passage of a fixing member (35).

7. Rotor according to claims 4 and 5, characterized in that the guide hole (37) has an axis (Y) intersecting the rotor body (23) outside the cavities (25) when the flange (27, 28) and the rotor body (23) are angularly indexed relative to one another.

8. Rotor according to claim 4, characterized in that it comprises a plurality of guide holes (37) and corresponding balancing holes (38).

9. Rotor according to claim 8, characterized in that the balancing holes (38) are located on each axial side of the rotor body (23).

10. Rotor according to claim 9, characterized in that the balancing holes (38) on one axial side of the body (23) are diametrically opposed to those made on the other axial side of the rotor body (23).

1 1. Rotor according to any one of claims 1 to 10, characterized in that the flanges (27, 28) comprise a plurality of guide holes (37), only part of which opens into a corresponding balancing hole (38).

12. Rotor according to any one of claims 1 to 1 1, characterized in that it comprises a plurality of fasteners (35), each fastener passing through both the flanges (27, 28) and the body (23) for holding together the flanges (27, 28) and the sheets of the sheet bundle (30).

13. Rotor according to any one of claims 1 to 12, characterized in that it is of flux concentration type.

14. Rotor according to any one of claims 1 to 12, characterized in that the permanent magnets (24) extend ortho-radially inside the cavities (25) of the rotor body (23).

15. Rotary electrical machine for a motor vehicle, characterized in that it comprises a rotor (12) as defined in any one of the preceding claims.