EP3662564A1

EP3662564A1 - Rotor for a rotating electrical machine with an improved flange mounting system

Info

Publication number: EP3662564A1
Application number: EP18737291.7A
Authority: EP
Inventors: Hugues Gervais; Michaël HANQUEZ; Virginie Leroy
Original assignee: Valeo Equipements Electriques Moteur SAS
Current assignee: Valeo Equipements Electriques Moteur SAS
Priority date: 2017-08-02
Filing date: 2018-07-12
Publication date: 2020-06-10
Also published as: WO2019025150A1; FR3069974A1

Abstract

The invention mainly relates to a rotor for a rotating electrical machine, particularly for a motor vehicle, comprising: - a body (12) comprising cavities opening axially at least on one side of the rotor body (12), - magnets housed in the cavities, and - at least one flange (24) comprising an opening for the passage of a shaft, - at least one mounting member (28) of the flange (24) on the rotor body (12), characterised in that a blind opening (40) defined by a circumferential face is formed in the body of the rotor (12) and in that - the mounting member (28) is configured to engage, in particular by expansion, with the circumferential face of said blind opening (40) of the rotor body (12).

Description

ROTOR OF ROTATING ELECTRIC MACHINE WITH IMPROVED FLASK MOUNTING SYSTEM

The invention relates to a rotating electric machine rotor with an improved flange fixing system. 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 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. 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 pack of sheets made of a magnetic material, in particular steel, as well as poles formed by a plurality of permanent magnets housed in cavities of the body.

Given the manufacturing tolerances of the various parts, it is ensured that the maximum cumulative length of the magnets is less than or equal to the minimum length of the corresponding cavity, in order to avoid breakage of the magnets during assembly of the closure flanges. However, this dimensional safety margin can lead to bad plating of the magnets inside the cavities which is likely to cause deterioration of the magnets, in particular due to shocks between the magnets and the internal faces of the cavities during the acceleration phases. of the rotor. As illustrated in Figure 1, to compensate for the mounting clearance, it is known to insert in each cavity 2 provided to accommodate the magnets 3, a spring 4 exerting a holding force on the corresponding magnets 3. A flange 5 closing the cavities can also be used to achieve balancing of the rotor. Reference can be made to WO13175117 for more details on this device.

Generally, the closure flange 5 of the cavities 2 is fixed against an end face of the sheet bundle by means of rivets passing right through the rotor body. However, such a configuration induces risks of buckling rivets at high speed and a large weight increasing the inertia of the rotor. There are also important constraints of positioning rivets to minimize electromagnetic interference.

The invention aims to remedy these drawbacks effectively by proposing a rotating electric machine rotor, particularly for a motor vehicle, comprising:

a body formed by a bundle of sheets, said body comprising cavities opening axially at least on one side of the rotor body,

magnets housed in the cavities, and

at least one flange comprising an opening for the passage of a shaft,

at least one fixing member of the flange on the rotor body,

characterized in that a blind aperture delimited by a circumferential face is formed in the rotor body and in that

- The fixing member is configured to bear, in particular by expansion, on the circumferential face of said blind opening of the rotor body.

The invention thus makes it possible to use fasteners which are shorter than the usual rivets, which makes it possible to reduce the weight of the rotor as well as the risks of buckling at high speed. The positioning constraints are also lower given the reduced size of the fasteners. According to one embodiment, the rotor comprises an axis of rotation and the greatest length of the fastener, measured along this axis, is strictly less than the largest length of the rotor body.

In one embodiment, a length of the fastener is less than a length of the rotor body.

In one embodiment, the fastener is an expansion rivet to hit.

In one embodiment, the fastener is a fir-tree.

According to one embodiment, the fastener is an expansion threaded insert.

According to one embodiment, the fastener is formed by at least one tongue of the flange, in particular a plate of the flange, inserted and fixed by deformation in the blind hole. This allows you to have no extra room.

According to an example of this embodiment, the tongue is obtained by cutting and folding, in particular by stamping or striking, a portion of a plate of the flange. During cutting which may be mechanical or laser, the tab is formed comprising an anchoring base integral with the plate. The free end and the longitudinal edges of the tongue are detached from the plate during the cutting operation. The tongue extends axially projecting relative to the corresponding cutting window in the blind hole.

According to an example of this embodiment, the fixing member comprises two tongues opposite inserted into the blind hole.

According to one embodiment, the fastener is formed by at least one tab of the inserted sheet package and fixed by deformation in the blind hole.

According to an example of this embodiment, the tongue comprises a base located in the blind hole, the closest to the plate of the flange and one end farthest from the plate of the flange and in that the axis or the center of the blind hole is farther away from the end of the tongue than the base of the tongue. Thus the flange is held axially against the rotor body.

According to one example, the fixing member comprises two tongues opposite inserted into the blind hole. In one embodiment, the rotor comprises at least two blind holes in the body and at least two fasteners. This makes it possible to immobilize the flange in rotation with respect to the rotor.

In one embodiment, the sheets are held together by gluing.

In one embodiment, the sheets are held together by welding. In one embodiment, the sheets are held together by riveting.

In one embodiment, the sheets are held together by riveting, and the flange is held on the rotor body by at least one fastener.

In one embodiment, the sheets are held together by buttoning. In one embodiment, the rotor body has relief recesses in its central portion.

In one embodiment, the magnets are implanted in a V configuration.

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, already described, is an exploded perspective view of a rotor provided with holding springs according to the state of the art;

Fig. 2 is a perspective view of a rotary electric machine rotor according to the present invention;

Figure 3 is a perspective view of the rotor of Figure 2 without the closure flange of the cavities; FIG. 4 is a perspective view of a first embodiment of a flange for closing the cavities according to the invention;

Figure 5 is a detailed perspective view of the contact between the spring tongues of the flange of Figure 4 and the end face of a magnet housed in a cavity of the rotor body;

FIG. 6 is a perspective view of a second embodiment of the flange for closing the cavities of the rotor according to the invention incorporating elastic members;

Fig. 7 is a schematic cross-sectional view illustrating the expansion of a rivet to be struck for securing a flange with the rotor body according to the invention;

Figures 8a and 8b are perspective views illustrating different types of fir pions that can be used in the invention to ensure the attachment of a flange with the rotor body; Figure 9 is a perspective view of an expansion rivet that can be used in the invention to secure a flange to the rotor body.

Identical, similar or similar elements retain the same reference from one figure to another. FIGS. 2 and 3 show a rotor 10 mounted on a shaft 11 comprising a body 12 formed by a bundle of sheets 14 made of a magnetic material, in particular steel, and a plurality of permanent magnets 13 intended to be housed in cavities 16 of the body 12.

The axially stacked sheets 14 of the pack may be held by means of rivets 17 passing axially through the rotor 10 through corresponding through holes 20 (see FIG. 3). Alternatively, the sheets 14 are held together by gluing, welding, or buttoning.

The rotor body 12 has a central opening 21 for the passage of the shaft 1 1 extending along the axis X. The shaft 1 1 can be force-fitted inside the opening 21 to connect in rotation the rotor body 12 with the shaft 1 1.

In its central part, the rotor body 12 has recesses 22 for lightening the rotor 10. More specifically, in a cutting plane P orthogonal to the X axis, the cavities 16 extend longitudinally in a direction D1, such that shown in FIG. 3. The cavities 16 may be axially through or of blind configuration, that is to say they open on one axial side of the body 12. The magnetic poles of the rotor 10 are each formed by the magnets 13 housed in two adjacent cavities 16 forming a V in the orthogonal plane P. In a variant, the cavities 16 extend in a radial or orthoradial direction with respect to the X axis.

Each cavity 16 receives a plurality of magnets 13 stacked axially on each other. In this case, each cavity 16 receives four magnets 13 of parallelepipedal shape. Alternatively, the number of magnets 13 may of course be different. A single magnet 13 may also be inserted inside each cavity 16. The permanent magnets 13 may be made of rare earth or ferrite depending on the applications and the desired power of the machine. Closure flanges 24 are each fixed against an axial end face of the rotor body 12. As can be seen in FIG. 4, each flange 24 comprises a plate 25 provided with a central opening 26 for the passage of the flange. tree 1 1. The flanges 24 are made of a non-magnetic material having high mechanical rigidity, for example non-magnetic steel. These flanges 24 can provide a balance of the rotor 10 while allowing good retention of the magnets 13 within their cavity 16. The balancing can be done by adding or removing material. The removal of material may be performed by machining, while the addition of material may be carried out by implanting elements in openings provided for this purpose and distributed along the circumference of the flange 24. As explained in more detail below, the flange 24 has at its outer periphery through-holes 27 for the passage of fasteners 28.

As can be seen in FIGS. 5 and 6, on one axial side of the rotor 10, a flange 24 is situated opposite the end-face faces of the cavities 16. The flange 24 comprises resilient members 30 , 30 'each bearing against an end face of a magnet 13 located inside the corresponding cavity 16. The elastic member 30, 30 'is configured to deform a force in an axial direction on the magnets 13 to maintain them in position within the corresponding cavity 16.

In the embodiment of FIGS. 2, 4 and 5, the resilient member is an elastically deformable tongue 30 made of material with the plate 25, that is to say that there is continuity of material between the tongue 30 and the plate 25.

The tongue 30 is obtained by cutting and folding, in particular by stamping or striking, a portion of the plate 25. During cutting which may be mechanical or laser, the tongue 30 is formed, for example of rectangular shape, having a anchoring end integral with the plate 25. The free end and the longitudinal edges of the tongue are detached from the plate 25 during the cutting operation. The tongue 30 extends axially projecting relative to the corresponding cutting window 32.

For this purpose, during folding, a protruding rounded portion 31 is formed in the tongue 30 which is intended to bear against an end face of the magnet 13. When the flange 24 is placed on the end of the rotor body 12, the tongue 30 is deformed by the end face of the magnet 13, so that the tongue 30 exerts by reaction an axial force on the magnets 13 to maintain them inside the cavity 16 corresponding. In this case, the tongue 30 has a single rounded portion but could alternatively comprise two or more rounded portions depending on the application and in particular the bearing area with the desired magnet 13. In the embodiment of Figure 6, the resilient member is an attached stud 30 'fixed on the plate 25. The stud 30' is for example made of plastic or rubber.

More precisely, the stud 30 'passes through an opening 34 of the plate 25. The insertion of the elastic stud 30 can for example be carried out by pegging.

In the example shown, the stud 30 'has two portions 35, 36 resting on either side of the plate 25 to ensure attachment of the elastic member on the plate 25. These portions 35, 36 are connected between they by a connecting portion 37 through the plate 25 via the opening 34. In other words, the plate 25 is clamped by the two portions 35, 36.

The portion 36 located on the side of the magnet 13 has a convex shape intended to bear against the end face of the magnet 13. The convex portion 36 is advantageously hollow to give it a better elasticity.

When placing the flange 24 on the end of the rotor body 12, the convex portion 36 is deformed by the end face of the magnet 13, so that the curved portion 36 exerts an axial force reaction on the magnets 13 to keep them inside the corresponding cavity 16. In all cases, the elastic member 30, 30 'has a thickness in maximum compressed position less than a distance between the end face of the magnet 13 and the end face of the flange 24.

The method of assembly of the rotor 10 which is simplified with respect to a conventional configuration is described below. This method consists on the one hand in position the lower flange 24 and then to set up the assembly formed by the shaft 1 1 and the rotor body 12. The magnets 13 are then inserted into packages inside cavities 16.

The upper flange 24 is then fixed against an end face of the rotor body 12, so that each elastic member 30 or 30 'comes to bear against a face of a corresponding magnet 13 to apply an axial holding force on the magnets 13. Only one of the flanges 24 can be provided elastic members 30 or 30 ', the other flange 24 being a plate without elastic member 30 or 30'.

The invention thus makes it possible, because of the integration of the elastic members 30, 30 'in one of the flanges 24, to limit as much as possible the number of assembly steps of the rotor 10.

To ensure the attachment of a flange 24 on the corresponding axial end face of the rotor 10, fasteners 28 are each inserted into a fastening hole 27 through the flange 24 and into a blind opening 40 in coincidence formed in the rotor housing 12, as shown in FIG. 3. The blind openings 24 and, if appropriate, the through holes 20 for the rivets 17, may be located along the same circumference of the rotor body 12.

Advantageously, an axial length of the fastener 28 is less than an axial length of the sheet package 14. This limits the magnetic disturbances given the reduced size of the fasteners inside the rotor body 12 .

The fixing member 28 is configured to bear on the circumferential face of the blind opening 40 of the sheet metal pack 14.

In the embodiment of FIG. 7, the fixing member is a striking rivet 41. The depression along the arrow F1 of the protruding portion 42 has the effect of radially spreading, according to the arrows F2, the end of the rivet 41 which thus abuts by expansion on the circumferential face of the blind opening 40 of the body rotor 12.

In the embodiment of FIGS. 8a and 8b, the fixing member 28 is a fir-tree pin 43 provided with flanges 44 intended to bear against the circumferential face of the blind opening 40 of the rotor body 12. For this purpose , the outer diameter of the flanges 44 in the unconstrained state is greater than the internal diameter of the blind opening 40 of the rotor body 12. The fir-tree pin 43 may comprise two parts separated from each other by a slot, as shown in FIG. Figure 8b. In the embodiment of Figure 9, the fastener 28 is an expansion threaded insert 45 having teeth 46 at its outer periphery. Its expansion inside the opening of the rotor body 12 is achieved by means of a screwing tool. According to another embodiment not shown, the fixing member is formed by at least one tongue of the flange, in particular a flange plate, inserted and fixed by deformation in the blind hole. This allows you to have no extra room. According to one example, the fixing member comprises two tongues opposite inserted into the blind hole. According to an example of this embodiment, the tongue is obtained by cutting and folding, in particular by stamping or striking, a portion of a plate of the flange. During cutting which may be mechanical or laser, the tab is formed comprising an anchoring base integral with the plate. The free end and the longitudinal edges of the tongue are detached from the plate during the cutting operation. The tongue extends axially projecting relative to the corresponding cutting window in the blind hole.

For example to fix the tongue or tongues in the blind hole, a tool can enter the blind hole once the tongue or tongues inserted (s) and move away by compressing the tongue or tabs in the circumferential face of said blind opening so as to deform this surface. The tongue and the surface of the hole may be deformed.

In one example, the tongue comprises a base located in the blind hole closest to the plate of the flange and one end farthest from the plate of the flange and in that the axis or the center of the blind hole is farther from the end of the tongue as the base of the tongue. Thus the flange is held axially against the rotor body.

For example, to deform the tongues in this way, a tool includes one or more rods that enter the blind hole once the tongue or tabs are inserted and the rod deviates from the axis or center of the hole. more importantly at its end (i.e., the downhole side) by compressing the tongue (s) in the circumferential face of said blind opening only at the base of the rod in the one-eyed hole.

Of course, these examples are in no way exhaustive and it will be possible to use any other type of similar device for fixing the flange 24 by insertion into a blind hole. Furthermore, the rotating electrical machine comprises a stator (not shown) surrounding the rotor 10 with the presence of an air gap. This stator comprises a body 12 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. 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. 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 (10) of a rotary electrical machine, in particular for a motor vehicle, comprising:

a body (12) formed by a bundle of sheets (14), said body (12) comprising cavities (16) opening axially at least on one side of the rotor body (12),

magnets (13) housed in the cavities (16), and

at least one flange (24) comprising an opening (26) for the passage of a shaft (1 1),

- at least one fastener (28) of the flange (24) on the rotor body (12),

characterized in that a blind opening (40) delimited by a circumferential face is formed in the rotor body (12) and in that

- The fixing member (28) is configured to bear, in particular by expansion, on the circumferential face of said blind opening (40) of the rotor body (12).

2. Rotor according to claim 1, characterized in that a length of the fastener (28) is less than a length of the rotor body (12).

3. Rotor according to claim 1 or 2, characterized in that the fastener (28) is a striking expansion rivet (41).

4. Rotor according to claim 1 or 2, characterized in that the fixing member (28) is a fir-tree (43).

5. Rotor according to claim 1 or 2, characterized in that the fastener (28) is an expansion threaded insert (45).

6. Rotor according to claim 1 or 2, characterized in that the fastener is formed by at least one tab of the inserted plate package and fixed by deformation in the blind hole.

7. Rotor according to any one of the preceding claims, characterized in that the sheets (14) are held together by welding or gluing.

8. Rotor according to any one of claims 1 to 6, characterized in that the sheets (14) are held together by riveting.

9. Rotor according to any one of claims 1 to 6, characterized in that the sheets (14) are held together by buttoning.

10. Rotor according to any one of claims 1 to 9, characterized in that the rotor body (12) has relief recesses (22) in its central portion.

1 1. Rotor according to one of Claims 1 to 10, characterized in that the magnets (13) are implanted in a V configuration.