Electric machine rotor including wedges for holding permanent magnets

Abstract

Rotor (10) for an axial flux electric machine, comprising a star-shaped body (8) including a hub (1) and arms (2) extending radially outwards from the hub, a slot (3) being formed between each pair of adjacent arms, each slot being configured to receive a magnet block (4), each slot being delimited on the bottom by a first wall (7) of the hub, and on each side by a face of the adjacent arms framing the slot, and comprising, in the first wall, a housing (6) receiving an elastomer shim (5), interposed between the first wall and a magnet block, the magnet blocks being radially bounded on the outside by a cylindrical collar (9) configured to exert a radial force on each of said magnet blocks so as to compress the elastomer shim between a magnet block and the hub. (Shorthand figure: Fig. 2)

Description

Title of the invention: Electric machine rotor comprising wedges for holding permanent magnets

[0001] The present invention relates generally to the rotors of electrical machines and more specifically to a permanent magnet rotor, the rotor comprising wedges for retaining the permanent magnets. The present invention also relates to an electrical machine equipped with such a rotor.

[0002] This discussion focuses particularly on electrical machines used in motor vehicles, especially electric and hybrid vehicles. However, the proposed rotor and the electric machine equipped with it can be used in applications other than electric vehicle traction.

[0003] An electric machine generally comprises a rotor forming a rotating part around a machine axis, and a stator forming a complementary non-rotating part, all housed in a casing.

[0004] There are many configurations of machines with so-called 'radial' flux. In this document, however, we are particularly interested in machines with so-called axial flux. The magnetic field in the air gap is oriented mainly parallel to the machine axis.

[0005] In axial flux machine configurations, the rotor has a general shape of a thick disk which has a thickness much smaller than its diameter.

[0006] As illustrated in document WO2020065488, an example of an axial flux rotor includes a star-shaped body, with a hub and radial arms, a magnet being disposed in the available gap between each pair of adjacent arms.

[0007] The electrical machines referred to can reach high rotational speeds, for example at least 12000 revolutions per minute (200 rpm), or even higher speeds.

[0008] Furthermore, to optimize the efficiency of the electric machine, particularly from the point of view of torque, the magnets must be placed as far away from the axis as possible.

[0009] As a result, the level of centrifugal force experienced by the rotor magnets is very high, and at the same time it is essential to ensure and maintain the mechanical cohesion of the rotor throughout the entire life cycle of the electric machine.

[0010] It is known to constrain the rotor magnets by a permanent preload directed radially inwards using a peripheral ring. The radial preload inwards counteracts the effects of the centrifugal force. However, The prestress can decrease over time, particularly due to the thinning of the materials.

[0011] The inventors sought to propose a solution for arranging and holding the magnets in an axial flux rotor, capable of withstanding very high rotational speeds while maintaining good mechanical cohesion, and maintaining satisfactory dynamic balance.

[0012] To this end, a rotor for an axial flux electric machine is proposed, comprising a star-shaped body including a hub and arms extending radially outwards from the hub, a space being formed between each pair of adjacent arms, the rotor comprising magnet blocks, each space being configured to accommodate a magnet block, each space being delimited on the one hand at the bottom by a first wall of the hub, and on the other hand on each side respectively by a face of the adjacent arms framing the space, the magnet blocks being radially bordered on the outside by a cylindrical collar, characterized in that a housing suitable for receiving an elastomer shim, interposed between the first wall and a magnet block, is provided in the first wall.The cylindrical ferrule is configured to exert a radial force on each of said magnet blocks so as to compress the elastomer shim between a magnet block and the hub.

[0013] Advantageously, the elastomer shim is compressed in the radial direction and absorbs part of the radial prestressing forces. Furthermore, the elastomer shim material does not undergo significant creep, and its prestressing force absorption remains constant over the rotor's life cycle.

[0014] This forms a reliable and robust radial alignment, compatible with very high rotation speeds and a very severe mission profile.

[0015] The term 'elastomer wedge' should be understood as a wedge made of elastic or resilient material, the qualifier elastomer being interpreted broadly and covering any type of elastic material.

[0016] The presence of the elastomer wedge and its elasticity also makes it possible to take into account the possible dispersions in the chain of ribs between the branches, the magnet block and the cylindrical fret.

[0017] It is noted that the rotor is configured to rotate around a rotor axis denoted A. The rotor has two principal faces which extend perpendicularly to the axis.

[0018] In the present document, a cylindrical spatial frame of reference based on the machine axis coinciding with the rotor axis A is used, as illustrated in [Fig. 2] at the top right. The terms "radially inward" and "radially outward" should be understood with respect to the rotor axis A. "Axially" characterizes a A direction parallel to or coinciding with the axis. "Tangently" characterizes a direction perpendicular to the local radius and perpendicular to the axis.

[0019] According to one embodiment, the elastomer wedge comprises a retaining base and a support head.

[0020] The retaining plate is housed in the housing. The bearing head projects radially outwards from the plate relative to the first wall. The retaining plate does not project beyond the first wall.

[0021] According to one embodiment, the hub includes a groove extending axially in the hub at the level of the first wall, the retaining plate has a shape complementary to said groove so as to allow the insertion of the plate into the groove.

[0022] The complementary shapes provide positive and reliable support of the wedge in the desired position.

[0023] According to one embodiment, the groove has a cylindrical cross-section, at least partially, with an opening facing radially outwards towards the location. The wedge includes a collar between the base and the head. This collar between the base and the head passes through the opening of the groove.

[0024] According to one embodiment, the groove opens onto at least one main face, i.e. one side of the hub, so as to make the elastomer wedge visible when the magnet block is mounted in the location.

[0025] According to an alternative embodiment, the housing includes a dovetail groove to allow the shim's base to expand under compressive stress. In other words, the compression of the shim causes the base to flare out, filling the lateral edges of the dovetail-shaped housing, thus reinforcing the shim's retention within the housing.

[0026] Advantageously, the housing is formed by a single machining stroke.

[0027] The housing comprises a bottom and an opening. The housing is dead-end. The housing comprises a first straight portion with a trapezoidal cross-section and a second bottom portion with a circular shape corresponding to the cutting part of the cutter.

[0028] According to one embodiment, the insertion direction of the wedge is parallel to the machine axis A. Consequently, the effects of centrifugal force are diminished with respect to the insertion direction of the wedge, which is perpendicular to the local radial direction. Indeed, the centrifugal force generated by the rotational speed does not tend to move the wedge backward.

[0029] According to one embodiment, the elastomer wedge is made of silicone.

[0030] This material can withstand a temperature of up to 140°C, without degradation of mechanical properties and without deterioration over the long term.

[0031] According to another embodiment, depending on the more or less demanding temperature resistance requirements, the elastomer wedge can be made of polyurethane.

[0032] According to one embodiment, the support head is symmetrical with respect to a median transverse plane of the rotor. Advantageously, the compression reaction does not create an axial component. The dynamic balance of the rotor is not altered.

[0033] According to one embodiment, the support head is symmetrical with respect to a median axial plane of the location and the housing.

[0034] According to one embodiment, an injected adhesive is provided from an injection point, preferably near the wedge, the injected adhesive being configured to fill at least one available gap between the first wall and the magnet block.

[0035] Cleverly, the presence of the glue prevents the wedge from coming out of its housing. Preferably, the glue is of the thermosetting type; it is noted that once the rotor assembly is complete, the rotor is non-removable, it is formed as a final and durable assembly.

[0036] According to one embodiment, the support head has the shape of a circular disc, preferably with a diameter between 0.4 x El and 0.85 x El, where El is the axial thickness of the hub. Preferably, the diameter of the support head may be between 0.5 x El and 0.85 x El.

[0037] According to one embodiment, the support head may have a diamond shape when viewed from the front. This type of shape can improve the penetration and progression of the adhesive during injection and its path to surround the support head of the wedge.

[0038] According to one embodiment, the glue continuously surrounds the support head at least in a tangential section.

[0039] According to one embodiment, the glue fills all the space left free between the first wall and the magnet block and between the magnet block and the faces of the adjacent branches framing the location.

[0040] The present invention also relates to an electric machine comprising at least one stator and at least one rotor as described above, the electric machine having a machine axis coinciding with the rotor axis, and the electric machine being intended to move a motor vehicle.

[0041] According to one embodiment, the electric machine can be intended to move a land vehicle of any kind, e.g. a railway vehicle, or even an aeronautical vehicle, or a maritime vehicle.

[0042] The present invention also relates to a method for mounting a rotor as described above, said method comprising the steps: - Mounting at least one elastomer shim at one bottom edge of the hub, - Mounting a magnet block in the hub housing so that the magnet block comes into contact with at least one elastomer shim, and - Mounting the cylindrical ring around the hub, said cylindrical ring exerting radial pressure on the magnet block so as to compress the elastomer shim between the hub and the magnet block, thus holding the magnet block in place between the hub and the cylindrical ring.

[0043] According to one embodiment, the process may further include a step of compressing the elastomer wedge prior to mounting the cylindrical collar, said collar allowing the elastomer wedge to be held compressed.

[0044] According to one embodiment, the method may further include a step of injecting glue between the hub and the magnet block so as to fix the magnet block to the hub or at least to fill the spaces between the magnet block and the hub, the elastomer shim being at least partly covered by said glue.

[0045] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.l] illustrates in a very schematic way an axial flux electrical machine; - [Fig.2] shows, schematically, according to a cross-section to the axis, a first example of an embodiment of the rotor according to the invention, two blocks of magnets being missing, figures 2 to 10 illustrating said first example of embodiment; - [Fig.3] schematically illustrates in perspective and partially the rotor body with a single magnet block in place; - [Fig.4] illustrates an area of ​​the hub with the mounting of an elastomer shim, seen from the front (section 4A) and seen from the side (section 4B); - [Fig. 5] illustrates, in a transverse view to the axis, the assembly of an elastomer shim, before assembly of the wedge; - [Fig. 6] illustrates in perspective view and partially an example of a rotor with a missing magnet block, after assembly of the wedge and compression; - [Fig. 7] illustrates in perspective view and partially an example of a rotor with a missing magnet block; - [Fig.8] illustrates in perspective view and partially an example of a rotor with a missing magnet block, according to another point of view; - [Fig.9] illustrates a cross-sectional view of a lateral slice of a magnet block received in branch grooves, along the cutting line IX-IX shown in the [Fig.2] view; - [Fig. 10] illustrates a variant where the support head of the wedge has a diamond shape, - [Fig. 11] shows, partially, according to a cross-section to the axis, a second embodiment of a rotor according to the invention, with a single block of magnet shown, figures 11 to 14 illustrating said second embodiment, - [Fig. 12] is similar to [Fig. 11] and illustrates in perspective view and partially the second example of a rotor with a magnet block, - [Fig. 13] illustrates in perspective view the hub with the locations for the magnet blocks and the housings for the wedges, - [Fig. 14] illustrates in perspective view an example of an elastomer wedge.

[0046] In the various figures, the same reference numerals designate identical or similar elements. For the sake of clarity, some elements are not necessarily shown to scale.

[0047] This document focuses on electrical machines used in motor vehicles. These may be machines of considerable power belonging to an electromotor unit capable of propelling the vehicle, i.e., so-called traction machines.

[0048] The electrical machine in question can operate in motor mode or in generator mode according to certain operating phases.

[0049] It should be noted, however, that the principle and technical solution advanced in this document can be applied to electrical machines other than traction machines or even outside of use in a motor vehicle.

[0050] The machine of interest can be installed on a land vehicle of any kind, e.g. a railway vehicle, or even an aeronautical vehicle, or a maritime vehicle.

[0051] General architecture (1st and 2nd examples of implementation)

[0052] As already mentioned in the introductory part and visible in [Fig.1], an axial flux electric machine identified as 100 generally comprises a rotor 10 forming a rotating part around a machine axis A, and at least one stator forming a complementary non-rotating part.

[0053] In the illustrated example, two stators 91,92 are provided, namely one stator on either side of the rotor.

[0054] The rotor 10 is rigidly connected to a machine shaft, denoted 11, as will be seen later. The rotor shaft is mounted for rotation about the axis A, relative to the housing, by means of bearings as known per se.

[0055] The rotor carries a series of permanent magnets, also referred to here as magnet blocks 4, while a series of coils is carried by the stators.

[0056] When the coils are supplied with an electric current, the rotor, which is fixed to the machine shaft 11, is subjected to a torque resulting from the field magnetic (the magnetic flux created being an axial flux for an axial flux electrical machine).

[0057] The rotor 10 has a general shape of a thick disc centered on the machine axis A.

[0058] The rotor has a thickness denoted El much smaller than its diameter D9. D9 can take a value between 150 mm and 450 mm.

[0059] In practice, the axial dimension of the rotor El can be chosen from 7 mm to 25 mm. According to a particular embodiment, El can be between 12 mm and 15 mm.

[0060] The rotor 10 has two main faces, designated 17 and 18 respectively, which are circular and opposite. Each of these faces 17, 18 is flat except in the central area of ​​the hub where it may have through holes.

[0061] Figures 2 to 10 illustrate a first embodiment of the invention, in which glue is injected in addition to the elastic spacer as described later. The term "glue" also refers to an agent used to fill gaps between the hub and the magnet.

[0062] Figures 11 to 14 illustrate a second embodiment of the invention. It should be noted that in this second embodiment, the presence of the glue is optional; the glue may be entirely absent.

[0063] As shown in Figures 1 to 3, the rotor 10 comprises a star-shaped body designated 8. The star-shaped body 8 comprises a hub 1 and arms 2 extending radially outwards from the body. The axial thickness of the hub is substantially the same as the axial thickness of the arms, which also corresponds substantially to the axial thickness El of the rotor.

[0064] According to one example, the star-shaped body 8 is made of composite material, for example, based on glass fibers embedded in a polymer resin.

[0065] It is not excluded to manufacture the star-shaped body in metal or in high mechanical performance synthetic material.

[0066] A location 3 is formed between each pair of adjacent branches.

[0067] The rotor 10 includes magnet blocks 4. Each location 3 is configured to accommodate one magnet block 4.

[0068] The number of magnet blocks 4 is identical to the number of arms 2 and the number of locations. In the illustrated example, this is a configuration with 12 magnet locations and 12 arms. The number in question could also be 16. It is possible that this number could be less than 12 or greater than 16.

[0069] The magnet blocks 4 are radially bordered on the outer side by a cylindrical collar 9. It is noted that the collar 9 may or may not be in contact with the distal ends 23 of the arms. The collar 9 exerts a radial compressive force. FC. The fret 9 absorbs the radial forces generated by the inertial forces exerted on the magnet blocks 4.

[0070] According to a preferred embodiment, the fret 9 is made of tension-wound carbon fibers.

[0071] According to one variant, the fret could be made of steel, aluminum alloy or titanium alloy, for example heated prior to assembly.

[0072] Each location 3 is delimited on the one hand at the bottom by a first wall 7 of the hub, and on the other hand on each side respectively by a face 21, 22 of the adjacent arms framing the location. In cross-section, each location 3 has a generally trapezoidal, or more complex, shape suitable for receiving a magnet block 4 by complementary shapes.

[0073] Each magnet block 4 is encapsulated in a plastic housing.

[0074] Each magnet block can comprise a plurality of juxtaposed unit magnets.

[0075] As can be seen more particularly from [Fig. 3], each magnet block 4 here has a generally trapezoidal shape. Each magnet block 4 thus comprises two principal faces 46, 47 of substantially trapezoidal shape, extending transversely to the axis A.

[0076] Each magnet block 4 comprises two lateral faces 41,42. Within the rotor 10, each lateral face 41,42 faces a branch 21,22.

[0077] Each magnet block 4 also includes an inner face 48, facing the hub 1. Finally, each magnet block 4 includes an outer face 49. The outer face 49 is located on the periphery of the rotor 10 and generally has an arc-shaped curvature. The outer face 49 is subjected to pressure by the collar 9.

[0078] According to one option, all the magnet blocks 4 are identical. A mechanical keying device 74 may be provided to prevent the magnet block from being mounted upside down.

[0079] Each magnet block 4 is held between two adjacent arms by means of sliding joints, here of the groove-rib type, which serve to retain the magnet block subjected to forces along axis A

[0080] To achieve sliding connections, in the example illustrated here, in particular illustrated in [Fig.9], each branch face includes a recessed groove 25 which extends along an extension direction of the branch 2, along the respective face 21,22.

[0081] In return, each magnet block 4 comprises, on each of its lateral faces 41, 42, a rib 45, configured to fit into one of the aforementioned grooves 25. Such an assembly limits the position of the magnet blocks 4 in translation along the axis A. The position is subsequently locked by injecting a spacer element between the magnet block 4 and the hub 1, as will be described later.

[0082] Of course, it would be possible to use reverse shapes, namely a rib on the arm and a groove on the magnet block.

[0083] Wedges (1st example of implementation)

[0084] Fig. 5 is a more detailed view of the area of ​​wedge 5 and its mounting in housing 6.

[0085] The elastomer wedge 5 comprises a retaining sole 51 and a support head 52.

[0086] According to one example, the elastomer wedge 5 is made of silicone. According to another example, the elastomer wedge can be made of polyurethane or any other thermoplastic material.

[0087] The support sole 51 is parallelepiped-shaped with a thickness E6. The thickness E6 can be between 1 mm and more than 3 mm, preferably between 1 mm and 3 mm. The support sole is generally parallelepiped-shaped. The support sole has a length H5 and a width L5.

[0088] The width L5 can, for example, be between 0.4 x El and 0.85 x El. The length H5 can, for example, be between 0.7 x El and 0.85 x El.

[0089] The wedge is inserted in the direction W, parallel to A, over a stroke substantially equal to H5. The housing being in a cul-de-sac, the insertion ends when the semi-circular part of the sole comes to rest against the bottom of the dovetail housing.

[0090] The support head 52 is symmetrical with respect to a median transverse plane of the PTM rotor. This is particularly evident in [Fig. 4]. The median transverse plane is located midway through the thickness of the rotor, equidistant from the main faces of the rotor.

[0091] The support head 52 has a thickness E7 which can be between 1 mm and more than 3 mm, preferably between 1 mm and 3 mm. The total thickness of the shim, denoted E5, is equal to the sum of E6 and E7.

[0092] Under a compressive stress of 500 Newton, the total thickness of the wedge 5 can decrease by 0.7 mm (in the case of a thickness less than 3 mm) due to its partial crushing.

[0093] When the wedge is compressed, as seen in [Fig.6], the base flares inside the dovetail profile 61.

[0094] Furthermore, the support head is symmetrical with respect to a median axial plane of the PAM location. The median axial plane PAM passes through axis A and separates the magnet block into two symmetrical parts.

[0095] According to the illustrated example, the support head has a circular disc shape, preferably with a diameter E2 between 0.4 x El and 0.85 x El, El being the axial thickness of the hub 1.

[0096] Preferably, a diameter E2 of the support head can be between 0.5 x El and 0.8 x El.

[0097] The housing 6 includes a dovetail groove 61, to allow the base of the wedge to expand under stress.

[0098] Glue (1st example of implementation)

[0099] According to the present configuration, it is planned to use an adhesive designated GF, also known in the trade as 'gap filler'. The adhesive is injected while in a paste-like phase, with sufficient fluidity to fill all the available spaces in the cavity defined by an injection mold in which the rotor is placed.

[0100] The GF glue is injected from an injection point 16 near the wedge, with an injection channel 15. Of course, the rotor 10 is placed in an injection mold so that the glue cannot overflow from the main faces 17,18 of the rotor.

[0101] The injected adhesive is configured to fill at least one available gap between the first wall 7 and the magnet block 4. From the injection channel 15, the GF adhesive continues its progression within the spaces left empty on either side of the support head via the channels 72 provided for this purpose. A vent may be provided to allow the air expelled by the advancing adhesive to escape.

[0102] Preferably, according to one embodiment, as seen in figures 7 and 8, the glue fills all the space left free between the first wall 7 and the magnet block 4 and the glue fills all the space left free between the magnet block 4 and the faces 21,22 of the adjacent branches framing the location.

[0103] In general, the injected GF glue is configured to fill at least one available gap between the first wall 7 and the magnet block 4.

[0104] The adhesive can be of the thermosetting type. After injection and filling of the empty spaces, the rotor is placed in the oven to solidify the GF adhesive.

[0105] Then the solidified glue confines the wedge in its position.

[0106] It is noted that GF glue can be subject to a fining phenomenon with time and prolonged exposure to inertial forces in a high temperature environment (100°C or more).

[0107] Wedges and housings (2nd example of implementation)

[0108] As apparent in Figures 11 to 13, the rotor hub 1 includes, at each location 3 for magnet block 4, a groove 6 which extends parallel to the axis of the rotor. This groove forms a housing to receive at least part of the elastic shim which is shown in [Fig. 14].

[0109] The groove has a cylindrical cross-section, at least in part, with an opening 64 open towards the opposite location 3. In other words, the opening 64 opens the groove along its length, radially outwards.

[0110] The groove opens axially through an opening 67 at least onto at least one main face 17 or 18, i.e., one side of the hub. It is through this axial opening, denoted 67, that the shim 5 is inserted.

[0111] It is noted that the elastomer shim remains visible when the magnet block 4 is mounted in the location 3. It is thus possible to check the presence and correct positioning of the shim once their rotor is fully equipped.

[0112] The groove may be open on one side only, in which case a groove bottom 60 is provided opposite the mouth 67.

[0113] The retaining base 51 of the wedge has a diameter D8, for example between 3 mm and 8 mm, the height of the wedge is uniform on the retaining base and the head, it is noted H8, H8 can be between 5 mm and 12 mm.

[0114] The support head has a thickness E7. E7 can be between 1 mm and 3 mm.

[0115] The support head has a width W8. W8 can be between 10 mm and 25 mm.

[0116] E7 + D8 represents the total dimension of the wedge in the radial direction.

[0117] The wedge 5 includes a collar 54 between the sole 51 and the head 52. Said collar 54 between the sole and head pass into opening 64 of the groove, and are housed there without play, which contributes to the locking of wedge 5. The dimension D7 of the neck can be, according to an evaluation example, close to half the diameter D8.

[0118] The hollow shape identified as 68 in [Fig. 13] allows, if necessary, for the injection of glue into the remaining gap between the magnet block and the hub 1. However, as already mentioned above, the presence of glue is not an obligatory option.

[0119] Additional features and miscellaneous characteristics

[0120] Regarding the assembly of the rotor, the shims 5 are first placed in the housings 6 (one shim per housing and per location, twelve in total in the illustrated example).

[0121] The shims stay firmly in place because, for the first embodiment, a width L5 slightly larger than the width of the upper opening of the dovetail joint can be chosen (resulting in a slight tightening during insertion). For the second embodiment, a diameter D8 slightly larger than the diameter of groove 6 can be chosen.

[0122] Then we place the magnet blocks 4 in the slots 3 (one per slot).

[0123] Then the fret 9 is placed or formed. The radial stress may result from the assembly even of the fret or a subsequent operation.

[0124] Then, for the first embodiment, the glue injection step explained above is carried out.

[0125] It is noted that it is not excluded to proceed with the step of injecting the glue before the installation of the fret 9.

[0126] In addition, it may be provided that the process includes a step of compressing the elastomeric shims prior to mounting the cylindrical collar, said collar allowing the elastomeric shim to be kept compressed.

[0127] The shaft can be fixed to the rotor via a flange by bolting using the holes 14 visible in [Fig.7]. This assembly is known per se and therefore not described in detail here.

[0128] Alternatively or in addition, the transmission of torque between the hub 1 and the shaft 11 can be done by means of a key 13 as shown in [Fig.2].

[0129] We note in [Fig.5], that the branch 2 socket includes a fillet 78 which reduces local stresses and increases resistance to stress and reduces a possible phenomenon of fatigue.

[0130] Regarding radial dimensions, the radius RI of the hub bore can typically be between 10 mm and 90 mm. These radial dimensions must be adapted according to the design, e.g., the desired power for the electric machine, the number of rotors, and the thickness of these rotors.

[0131] The radius R2 of the hub can typically be between 20 mm and 100 mm. The radius R3 at the end of the spokes can typically be between 80 mm and 200 mm. The radius R9 (D9 / 2) outside the flange 9 can typically be between R3 plus the thickness of the flange, which can range from less than 6 mm to 35 mm, preferably from 6 mm to 35 mm.

[0132] As illustrated in [Fig.8], it is planned to be possible to check the correct presence of the wedge 5 in the housing 6 even after filling the gaps with glue GF, thanks to the flush end 53 of the base 51 of the wedge 5.

[0133] The axial thickness E4 of the ribs 45 can be between 1 / 5 and 1 / 3 of El.

[0134] As illustrated in [Fig. 10], the support head 52 may, instead of a circular cross-section, have a diamond or square shape when viewed from the front. Depending on the viscosity of the adhesive, this arrangement may facilitate the flow of the adhesive and the filling of all available volume gaps.

[0135] Other forms of support head are of course possible, preferably with symmetry with respect to the median transverse plane PTM as well as symmetry with respect to the median axial plane PAM.

[0136] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the features of the different embodiments of the invention envisaged in this application can be combined to carry out the invention, provided that these embodiments are not incompatible with each other.

[0137] It should be noted that with regard to the second embodiment example, everything that is not described again is assumed to be identical or similar to what was described for the first embodiment example.

Claims

Demands

1. Rotor (10) for an axial flux electric machine, comprising a star-shaped body (8) including a hub (1) and arms (2) extending radially outwards from the hub, a slot (3) being formed between each pair of adjacent arms, the rotor comprising magnet blocks (4), each slot being configured to receive a magnet block (4), each slot being delimited on the one hand at the bottom by a first wall (7) of the hub, and on the other hand on each side respectively by a face of the adjacent arms framing the slot, the magnet blocks being radially bordered on the outside by a cylindrical collar (9), characterized in that a housing (6) adapted to receive an elastomer shim (5), interposed between the first wall and a magnet block,said cylindrical fret (9) being configured to exert a radial force on each of said magnet blocks (4) so ​​as to compress the elastomer wedge (5) between a magnet block (4) and the hub (1), and in that the elastomer wedge comprises a retaining plate (51) and a support head (52).

2. Rotor according to the preceding claim, wherein the hub includes a groove extending axially at the level of the first wall (7), the retaining plate has a shape complementary to said groove so as to allow the insertion of the plate into the groove.

3. Rotor according to claim 2, characterized in that the groove opens onto at least one side of the hub, so as to make the elastomer wedge visible when the magnet block is mounted in the location.

4. Rotor according to any one of claims 1 to 3, characterized in that the housing includes a dovetail groove (61) to allow the wedge retaining base to expand under compressive stress.

5. Rotor according to any one of claims 1 to 4, characterized in that the insertion direction (W) of the wedge is parallel to the rotor axis (A).

6. Rotor according to any one of claims 1 to 5, wherein the elastomer wedge is made of silicone.

7. Rotor according to any one of claims 1 to 6, wherein an injected adhesive is provided from an injection point (16), preferably near the wedge, the injected adhesive being configured to fill at least one available gap between the first wall and the magnet block.

8. An electric machine comprising at least one stator and at least one rotor according to any one of claims 1 to 7, the electric machine having a machine axis coinciding with the rotor axis, and the electric machine being intended to move a motor vehicle.

9. A method for mounting a rotor according to any one of claims 1 to 7, said method comprising the steps of: - Mounting at least one elastomer shim (5) at a bottom edge of the hub (1), the elastomer shim comprising a support plate housed in a housing of the hub, - Mounting a magnet block (4) in the housing of the hub (1) such that the magnet block (4) comes into contact with at least one elastomer shim (5), and - Mounting the cylindrical ring (9) around the hub (1), said cylindrical ring (9) exerting radial pressure on the magnet block (4) so ​​as to compress the elastomer shim (5) between the hub (1) and the magnet block (4), thus holding the magnet block (4) in place between the hub (1) and the cylindrical ring (9).

10. Method according to the preceding claim, further comprising a step of compressing the elastomer wedge prior to mounting the cylindrical collar, said collar allowing the elastomer wedge to be held compressed.