Electric machine rotor with a recess comprising an adhesive

Abstract

The invention relates to a rotor and an electric machine, the rotor comprising: - a rotor body (7), and - a plurality of pairs of magnetic poles (P), each magnetic pole (P) comprising at least one flux barrier, each flux barrier comprising at least one recess (1), each magnetic pole (P) comprising at least one permanent magnet (6) in a recess (1). Moreover, each recess (1) in which a permanent magnet (6) is inserted has a groove (4), the groove (4) being filled with glue for fixing the permanent magnet (6) in the recess (1).

Description

[0001] ELECTRIC MACHINE ROTOR WITH A RECESS COMPRISING AN ADHESIVE

[0002] Technical field

[0003] The present invention relates to a rotating synchro-reluctant electrical machine (assisted by permanent magnets) or with buried magnets and more particularly concerns the particular architecture of a rotor of such a machine.

[0004] Typically, such an electrical machine has a stator and a rotor arranged coaxially within each other.

[0005] The rotor consists of a rotor body with a stack of laminations placed on a rotor shaft. These laminations include housings for permanent magnets and perforations to create flux barriers to direct the magnetic flux from the magnets radially towards the stator and to promote the creation of a reluctant torque, and to lighten this rotor to reduce the centrifugal forces that the stack of laminations must withstand.

[0006] This rotor is generally housed inside a stator which carries electrical windings to generate a magnetic field to drive the rotor in rotation.

[0007] Prior art

[0008] As better described in particular in patent application WO2020 / 020580, the rotor of a synchro-reluctant machine comprises a plurality of axial recesses which pass right through the sheets.

[0009] For the rotor design described in this patent application, a first series of axial recesses, arranged radially above each other and at a distance from each other, form housings for magnetic flux generators, here permanent magnets in the form of a rectangular bar.

[0010] The other series of recesses consists of perforations of inclined radial direction, which start from these housings to arrive in the vicinity of the edge of the sheets, in the vicinity of the air gap.

[0011] The inclined perforations are arranged symmetrically with respect to the magnet housings so as to form each time a geometric figure substantially in the shape of a V with a flattened bottom with the flat bottom formed by the magnet housing and with the inclined arms of this V formed by the perforations. This creates flux barriers formed by the perforations. The magnetic flux coming from the permanent magnets can then only pass through the solid parts between the perforations. These solid parts are made of a ferromagnetic material. In a known manner, the permanent magnets are held in position in the rotor recesses using glue (also called resin or any other adhesive component allowing the permanent magnet to be held in position in the recess).The recess in which a permanent magnet is inserted is then filled with glue, which means that the volume of the recess containing the permanent magnet(s) is either filled by the permanent magnet or by the glue which then fills the space of the recess free of permanent magnets (in other words, the permanent magnet is cast in the glue in the recess in which it is inserted). As a result, the extraction of the permanent magnet for repair or the separation of the permanent magnet from the rotor body, for recycling in particular, involves at best the deterioration of the permanent magnet, if not an impossibility of extracting it from the rotor. This constitutes a major obstacle in the recycling industry for electrical machines and more particularly for permanent magnets.Indeed, the magnet is a strategic and critical material because it requires rare materials (also called "rare earths" and "heavy rare earths") while it provides a densification of performance and thus a reduction of other materials making up the machine (copper, magnetic iron, aluminum), a reduction in the size of the inverter (lower current for a given torque), and an increase in the efficiency of the powertrain reducing the size of the battery (for example, lithium battery) for a given autonomy.

[0012] In particular, patent application US 2013 / 270954 AA is known, which relates to an electric machine rotor. The rotor of this electric machine comprises a rotor body and permanent magnets that are on the surface of the rotor body (and not inserted into the rotor body). Grooves are placed on the surface of the rotor body in contact with the permanent magnets to increase the magnetic force allowing the magnets to be held on the rotor body. In addition, glue can be applied to the interface between the rotor body and the permanent magnets. However, the adhesive force is applied to the entire interface surface. As a result, dismantling the permanent magnets is complex. In addition, the permanent magnets of this machine are arranged on the surface of the rotor.However, the solutions suitable for this machine topology cannot be transposed as they are to a magnet-assisted synchro-reluctant machine topology or to a machine with buried magnets.

[0013] To improve the recyclability of electrical machines and more particularly permanent magnets, the technical problem that the invention seeks to solve consists of making the magnets more easily removable, without damaging them, so that they can be reprocessed and put back into the production of electrical machines. It is therefore necessary to improve the process for holding the magnet in position by making it removable.

[0014] Summary of the invention

[0015] The invention relates to an electric machine rotor comprising:

[0016] - a rotor body, formed by a stack of sheets, preferably configured to be positioned on a rotor shaft, and

[0017] - a plurality of pairs of magnetic poles distributed circumferentially on the rotor body, each magnetic pole comprising at least one flux barrier, preferably at least two flux barriers located radially above each other, each flux barrier comprising at least one recess, each magnetic pole comprising at least one permanent magnet in a recess.

[0018] In addition, each recess into which a permanent magnet is inserted further comprises a groove, the groove being filled with an adhesive component for fixing the permanent magnet in the recess.

[0019] According to an advantageous embodiment, the groove has a predefined maximum depth, preferably the groove being defined by a rounded arcuate profile or by a groove.

[0020] Preferably, the width of the groove is less than 50% of the width of the permanent magnet. Advantageously, the predefined maximum depth is between 0.5 and 2 mm, preferably between 0.8 and 1.2 mm.

[0021] According to one implementation of the invention, the groove is positioned on the surface of the recess closest to the axis of rotation of the rotor.

[0022] Depending on a configuration, permanent magnets are prismatic or non-prismatic.

[0023] Advantageously, each magnetic pole comprises a single flux barrier comprising two lateral recesses, each lateral recess comprising a prismatic permanent magnet.

[0024] Preferably, each recess comprises a plurality of grooves, each groove being filled with adhesive component.

[0025] The invention also relates to an electrical machine comprising a stator and a rotor as described, said rotor being housed inside said stator.

[0026] Advantageously, said electric machine is of the synchro-reluctant electric machine type.

[0027] List of figures Other characteristics and advantages of the rotor and the electrical machine according to the invention will appear on reading the following description of non-limiting examples of embodiments, with reference to the figures appended and described below.

[0028] Figure 1 shows an example of a recess for flow barriers with a groove for the placement of the adhesive component, of a rotor for an electric machine according to the invention.

[0029] Figure 2 shows a first embodiment of a glued assembly of a permanent magnet in a flux barrier recess with a groove for the placement of the adhesive component, of a rotor for an electric machine according to the invention.

[0030] Figure 3 shows a second embodiment of a glued assembly of a permanent magnet in a flux barrier recess with a groove for the placement of the adhesive component, of a rotor for an electric machine according to the invention.

[0031] Figure 4 shows a perspective view of a prismatic permanent magnet with the adhesive component intended to be placed in the groove of the recess of a flux barrier, of a rotor for an electrical machine according to the invention.

[0032] Figure 5 shows an embodiment of a rotor for an electrical machine comprising several flux barriers with permanent magnets bonded to each recess via a groove, according to the invention.

[0033] Description of the embodiments

[0034] The invention relates to a rotor for an electrical machine, in particular for an electrical machine, for example of the buried magnet type, and more particularly for a synchro-reluctant type machine assisted by permanent magnets. Furthermore, the present invention relates to an electrical machine, preferably of the synchro-reluctant type, comprising a rotor according to the invention and a stator, the rotor being arranged within the stator, preferably coaxially therewith.

[0035] "Buried magnets" are magnets that are inserted within the rotor itself, unlike surface magnets that are only arranged on the surface of the rotor and are only separated from the stator by an air gap corresponding to the functional clearance between the stator and the rotor (this clearance generally being called "air gap"). According to the invention, the electrical machine rotor comprising:

[0036] - a rotor body, formed by a stack of sheets, preferably configured to be positioned on a rotor shaft, and

[0037] - a plurality of pairs of magnetic poles distributed circumferentially on the rotor body.

[0038] Each magnetic pole comprises at least one flux barrier, preferably at least two flux barriers located radially above each other and each flux barrier comprises at least one recess. In addition, each magnetic pole comprises at least one permanent magnet in a recess.

[0039] The recesses of the flux barriers are axial. In other words, the recesses extend in the axial (longitudinal) direction, i.e. along the rotor axis, crossing the rotor along its entire axial length.

[0040] Permanent magnets generate a magnetic flux, allowing the rotor to rotate by creating a rotating magnetic field that can also be generated by the stator. Flux barriers guide the magnetic field generated by the rotor and by the at least one permanent magnet towards the air gap (the air gap being the space formed between the periphery of the rotor and the stator), so as to limit magnetic flux leakage and increase the performance (particularly torque and power) of the electrical machine. A pair of magnetic poles comprises two magnetic poles of opposite polarity.

[0041] The recesses in which permanent magnets are inserted are fully inserted into the rotor body: in other words, the magnets are inserted (buried) into the rotor body and are not positioned on the surface of the rotor body. Thus, the performance of the electric machine is improved.

[0042] Furthermore, each recess into which a permanent magnet is inserted comprises at least one groove, the at least one groove being filled with an adhesive component (in particular a glue or a resin) for fixing the permanent magnet in the recess. In other words, the recess comprises a shape for inserting a permanent magnet and an additional groove (or notches) for the adhesive component. Thus, the adhesive component used to hold the permanent magnet in position in the recess is limited to the surface of the groove (or grooves) in contact with the permanent magnet. Unlike the prior art, the bonding area of ​​the invention constitutes a reduced area of ​​the surface of the magnet.Thanks to this reduced bonding surface (limited to at least one groove), the permanent magnet can be more easily disassembled, for example by local machining of the adhesive component or by distributed support on the visible surface of the magnet which would constrain the adhesive component in shear. As a result, the permanent magnet can be removed from the recess without damaging the permanent magnet. Subsequently, the term glue is used to designate the adhesive component but it is understood that the glue described could be replaced by another adhesive component such as a resin.

[0043] The groove forms a hollow on the rotor body, allowing the glue to be placed in the groove.

[0044] In an advantageous configuration, the glue used to hold the permanent magnet in the recess can be limited to the groove (or grooves): in other words, the glue can be placed only in the groove (or grooves). There is therefore no glue on the surface of the recess outside the areas where the grooves are located.

[0045] Advantageously, the glue surface (the groove surface at the interface with the permanent magnet) on the permanent magnet can be adapted to the level of vibrations expected on the rotor.

[0046] Advantageously, the groove can extend over the entire longitudinal length (along the rotor axis) of the rotor body. Thus, an adhesive surface of the permanent magnet can be ensured over the entire length in contact with the rotor body.

[0047] Advantageously, each recess may be formed between two lines, for example between an upper line and a lower line. The upper and lower lines delimit the upper and lower edges of the flow barriers and form an upper surface (formed by the upper line and extending along the entire axial length of the rotor body) and a lower surface (formed by the lower line and extending along the entire axial length of the rotor body).

[0048] The terms "upper" and "lower" extend radially from the rotor axis. In other words, the upper line (top edge) and upper surface of a recess is farther from the rotor axis than the lower line (bottom edge) and lower surface of the same recess.

[0049] According to one configuration of the invention, the groove may have a predefined maximum depth so as to optimize the adhesive force.

[0050] The predetermined maximum depth is the greatest value of the depth of the groove in relation to the surface of the recess on which it is installed. This maximum depth therefore corresponds to the maximum thickness of glue that can be placed between the bottom of the groove and the permanent magnet.

[0051] Advantageously, the groove (or at least one groove) can be defined by a rounded profile in an arc of a circle (for example by a predefined radius) and preferably, the groove can have a predefined maximum depth, or by a groove (of rectangular or square section for example or substantially parallelepiped, preferably with rounded edge shapes) of predetermined maximum depth. This rounded profile or this groove allows easy production of the groove by industrial sheet metal cutting tools (laminations) and allows good cohesion to be ensured by the adhesive bonding force.

[0052] According to one implementation of the invention, the width of the groove (or the sum of the widths of the different grooves filled with glue) may be less than 50%, preferably less than 25% and even more preferably less than 10%, of the width of the permanent magnet.

[0053] Groove width means the width of the groove at the interface between the groove and the permanent magnet. When the groove is a rectangular groove (preferably with rounded edges), the width is the width of the groove, width at the interface with the permanent magnet.

[0054] The width of a permanent magnet refers to the dimension of the magnet in the direction parallel to the groove width. For a curved permanent magnet, the width can be considered the length of the chord at the neutral line (also called the neutral fiber) of the permanent magnet.

[0055] Additionally or alternatively, the bonding surface may be limited to a maximum of 50% of the outer surface of the permanent magnet, preferably less than 25% and more preferably less than 10% of the outer surface of the permanent magnet.

[0056] By limiting the bonding surface, the permanent magnet is easier to dismantle and easier to recycle. In addition, the permanent magnet can be dismantled without damaging it.

[0057] According to a variant of the invention, the predefined maximum depth may be between 0.5 and 2 mm, preferably between 0.8 and 1.2 mm. Such a depth makes it possible to ensure a sufficient volume of glue to ensure that the permanent magnet is held in position.

[0058] Alternatively, when the groove is a groove of rectangular section, the depth of the groove may be between 0.5 and 2 mm, preferably between 0.8 and 1.2 mm. Such a depth ensures a sufficient volume of glue to ensure that the permanent magnet is held in position.

[0059] According to one embodiment of the invention, the groove can be positioned on the surface of the recess closest to the axis of rotation of the rotor (lower surface of the recess). Indeed, the recess can be delimited by an upper surface and a lower surface, the upper surface being further from the axis of the rotor than the lower surface. This embodiment allows for easier production.

[0060] Preferably, the groove may be positioned on the surface of the recess furthest from the axis of rotation of the rotor (upper surface of the recess) to allow for facilitated contact between the upper surface of the recess and the magnet using centrifugal force which tends to naturally push the magnet towards the upper surface.

[0061] Advantageously, the permanent magnets can be prismatic or non-prismatic. Prismatic permanent magnets allow simple realization of the invention. Non-prismatic magnets can be produced for example by machining or by powder sintering techniques or by injection. In addition, the non-prismatic magnets can adapt to recesses of complex shape, for example to recesses used to form flux barriers of concave shape (whose center line, i.e. the middle line, is concave and preferably without discontinuities).

[0062] A "center line" is a line that is equidistant from the edges of the flux barrier (which face the center and periphery of the rotor, respectively), this center line is defined in a cross-section of the rotor (i.e. in a plane perpendicular to the rotor axis).

[0063] A line "without discontinuities" means that the line in question is entirely differentiable and that there is no point where the derivative on one side of the point is not equal to the derivative on the other side of the point. When a flux barrier is formed by a plurality of recesses separated in particular by at least one magnetic bridge, the center line also crosses the magnetic bridge. In other words, a magnetic bridge does not form a discontinuity in the center line.

[0064] According to an advantageous embodiment of the invention, each magnetic pole may comprise a single flux barrier comprising two lateral recesses, each lateral recess comprising a prismatic permanent magnet. Each lateral recess extends between two surfaces, an upper surface and a lower surface, the two surfaces preferably being parallel to each other. Thus, the rotor may be a V-shaped rotor with bonding to limit the number of magnets to be placed in the rotor.

[0065] Preferably, each recess may comprise several grooves, each groove being filled with glue, for fixing the permanent magnet in the recess. The use of several grooves filled with glue makes it possible to increase the adhesive strength and to increase the bonding surface between the rotor body and the permanent magnet. Increasing the adhesive strength is particularly advantageous in the event of strong vibrations expected during operation. The glue can then be limited to the individual grooves: there is no glue outside the groove areas, so as to facilitate disassembly and recycling of the permanent magnet.

[0066] When multiple glue-filled grooves are placed on a single recess, the grooves may all be positioned on the recess surface closest to the rotor's axis of rotation (lower recess surface) or on the surface furthest from the rotor's axis of rotation (upper recess surface). Alternatively, at least one groove may be positioned on the recess surface closest to the rotor's axis of rotation (lower recess surface) and at least one other groove may be positioned on the recess surface furthest from the rotor's axis of rotation (upper recess surface).

[0067] Figure 5 illustrates, in a schematic and non-limiting manner, a rotor for an electric machine according to the invention.

[0068] The rotor comprises a rotor body 7 made of rolled sheets of ferromagnetic material. The rotor body 7 comprises four magnetic poles P (but could comprise a different number of magnetic poles, the number of poles being a multiple of two).

[0069] Each magnetic pole P shown in the figure comprises a single flux barrier (but could comprise several flux barriers positioned radially above each other).

[0070] The magnetic flux barrier of each magnetic pole P here comprises two lateral recesses 1 and a permanent magnet 6 is inserted into each of the lateral recesses 1 of each magnetic pole P. Alternatively, the flux barriers could comprise a single recess or more than two recesses and / or some recesses could not comprise permanent magnets.

[0071] Each lateral recess 1 is delimited by an upper surface 2 and a lower surface 3.

[0072] The upper 2 and lower 3 surfaces of the recesses are defined with respect to radial lines (represented by the dot-dash line) passing through the center C (through the axis of rotation of the rotor). The radial line intersects the lower surface at a point 11 and intersects the upper surface at a point 10. We speak of an upper surface when point 10 is at a distance from the center C greater than the distance from point 11 to the center C. Conversely, we speak of a lower surface when point 11 is at a distance from the center C less than the distance from point 10 to the center C.

[0073] The rotor body 7 is delimited by an internal diameter 8, capable of engaging on a rotor axis (not shown) and by an external diameter 9, capable of being introduced into the stator (not shown) coaxial and surrounding the rotor. The stator and the rotor thus form an electrical machine and more particularly an electrical machine of the synchro-reluctant type.

[0074] Each recess 1 in which a permanent magnet 6 is inserted comprises a groove 4, which is filled with glue for holding the permanent magnet 6 in the rotor body 7.

[0075] Apart from the groove 4 filled with glue, the volume of the recess 1 which is not filled by the permanent magnet 6, in particular, the end volumes 12, are not filled with glue and are therefore free areas where air can circulate, facilitating the cooling of the permanent magnets. Thus, the bonding area between each recess 1 and the permanent magnet 6 inserted therein is limited to the groove 4.

[0076] As shown in the figure, each groove 4 is positioned on the upper surface 2 of each recess 1 but could also be located on the lower surface 3 of each recess 1. Similarly, each recess 1 could comprise several grooves 4 located on the upper surface 2 and / or on the lower surface 3.

[0077] Figure 1 illustrates, in a schematic and non-limiting manner, an example of a recess with a groove in a rotor for an electrical machine according to the invention.

[0078] The recess 1 shown comprises an upper surface 2 and a lower surface 3, which are here parallel to each other (they might not be parallel). As shown, the upper 2 and lower 3 surfaces are flat and therefore the recess 1 is suitable for the placement of prismatic permanent magnets. Of course, the upper 2 and lower 3 surfaces could be generated from curved lines, in particular concave ones, extending over the entire axial length of the rotor body, so as to adapt to non-prismatic permanent magnets, thus making it possible to increase the electromagnetic performance of the electrical machine.

[0079] The recess 1 comprises a groove 4 forming a hollow in the rotor body. Here, the groove 4 is positioned on the upper surface 2 but could alternatively be positioned on the lower surface 3.

[0080] The groove 4 is a rounded profile, forming an arc of a circle, of predetermined radius R and predetermined maximum depth Lp. The predetermined maximum depth corresponds to the distance between the bottom of the groove 4 forming an arc of a circle and the upper surface 2 (but could be the lower surface if the groove 4 were positioned there). For example, the predetermined maximum depth Lp is between 0.5 mm and 2 mm. Alternatively, the groove could be made by a groove of rectangular or square section in particular or substantially parallelepipedal, preferably, with rounded edge shapes. The predetermined maximum depth would then be the distance between the bottom of the groove and the upper surface of the recess (but could be the lower surface if the groove were positioned there).In addition, the width L of the groove at the interface with the permanent magnet forms a reduced bonding zone, i.e. a bonding surface which represents less than 50% of the external surface of the permanent magnet.

[0081] Figure 2 illustrates, in a schematic and non-limiting manner, a first example of mounting a permanent magnet 6 in a recess 1 of a rotor for an electrical machine according to the invention.

[0082] The recess 1 shown comprises an upper surface 2 and a lower surface 3, which are here parallel to each other but could not be parallel. As shown, the upper 2 and lower 3 surfaces are flat and therefore the recess 1 is suitable for the placement of prismatic permanent magnets. Of course, the upper 2 and lower 3 surfaces could be generated from curved lines, in particular concave ones, extending over the entire axial length of the rotor body, so as to adapt to non-prismatic permanent magnets, thus making it possible to increase the electromagnetic performance of the electrical machine.

[0083] The recess 1 comprises a groove 4 forming a hollow in the rotor body. Here, the groove 4 is positioned on the upper surface 2 but could alternatively be positioned on the lower surface 3.

[0084] The groove 4 is a rounded profile, forming an arc of a circle, of predetermined radius R and of predetermined maximum depth Lp. The predetermined maximum depth corresponds to the distance between the bottom of the groove 4 forming an arc of a circle and the upper surface 2 (but could be the lower surface if the groove 4 were positioned there) and therefore to the maximum distance between the bottom of the groove 4 and the permanent magnet 6. For example, the predetermined maximum depth Lp is between 0.5 mm and 2 mm. Alternatively, the groove could be made by a groove of rectangular or square section in particular or substantially parallelepipedal, preferably, with rounded edge shapes.The predetermined maximum depth would then be the distance between the bottom of the groove and the upper surface of the recess (but could be the lower surface if the groove were positioned there) and then corresponds to the maximum distance between the bottom of the groove and the permanent magnet 6.

[0085] In addition, the width L of the groove at the interface with the permanent magnet forms a reduced bonding area. The width of the groove L is less than 50% of the width of the permanent magnet L2. Thus, the bonding surface represents less than 50% of the outer surface, preferably less than 50% of the upper surface or the lower surface on which the groove is located.

[0086] The permanent magnet 6, here prismatic, is inserted into the recess 1 and glue 5 is placed in the groove 4 to hold the permanent magnet 6 in position in the recess 1. Alternatively, glue could be placed in the groove of the recess and then the permanent magnets inserted into the recess.

[0087] The glue zone 5 is limited to the groove 4. In particular, there is no glue in the end volumes 12 of the recess 1, located on either side of the permanent magnet 6.

[0088] Figure 3 illustrates, in a schematic and non-limiting manner, a second example of mounting a permanent magnet 6 in a recess 1 of a rotor for an electrical machine according to the invention.

[0089] The recess 1 shown comprises an upper surface 2 and a lower surface 3, which are parallel to each other (but which might not be parallel). As shown, the upper 2 and lower 3 surfaces are planar and therefore the recess 1 is suitable for the placement of prismatic permanent magnets. Of course, the upper 2 and lower 3 surfaces could be generated from curved lines, in particular concave ones, extending along the entire axial length of the rotor body, so as to accommodate non-prismatic permanent magnets, thus increasing the electromagnetic performance of the electrical machine.

[0090] The recess 1 comprises a groove 4 forming a hollow in the rotor body. Here, the groove 4 is positioned on the lower surface 3.

[0091] Groove 4 is a rounded profile, forming an arc of a circle, with a predetermined radius R and a predetermined maximum depth Lp.

[0092] The predetermined maximum depth corresponds to the distance between the bottom of the groove 4 forming an arc of a circle and the upper surface 2 (but could be the lower surface if the groove 4 were positioned there) and therefore to the maximum distance between the bottom of the groove 4 and the permanent magnet 6. For example, the predetermined maximum depth Lp is between 0.5 mm and 2 mm. Alternatively, the groove could be made by a groove of rectangular or square section in particular or substantially parallelepipedal, preferably, with rounded edge shapes. The predetermined maximum depth would then be the distance between the bottom of the groove and the upper surface of the recess (but could be the lower surface if the groove were positioned there) and then corresponds to the maximum distance between the bottom of the groove and the permanent magnet 6.

[0093] In addition, the width L of the groove at the interface with the permanent magnet forms a reduced bonding area. The width of the groove L is 50% inside the width of the permanent magnet L2. Thus, the bonding surface represents less than 50% of the outer surface, preferably less than 50% of the upper surface or the lower surface on which the groove is installed. The permanent magnet 6, here prismatic, is inserted into the recess 1 and glue 5 is placed in the groove 4 to hold the permanent magnet 6 in position in the recess 1.

[0094] The glue zone 5 is limited to the groove 4. In particular, there is no glue in the end volumes 12 of the recess 1, located on either side of the permanent magnet 6.

[0095] Figure 4 illustrates, in a schematic and non-limiting manner, a permanent magnet with its bonding zone according to the invention.

[0096] The permanent magnet 6 shown is prismatic but it could be of non-prismatic shape to increase the electromagnetic performance of the electric machine. The permanent magnet 6 is coated with glue 5 on the area shown in black in the figure, this area extending over the entire length of the permanent magnet (which corresponds to the axial length of the rotor body along the axis of rotation of the rotor). This area of ​​glue 5 is reduced and does not cover the entire outer surface of the magnet. The width of glue L at the interface between the groove (in which the glue is placed) and the permanent magnet 6 is less than the width L2 of the magnet. The width L of glue 5 represents less than 50% of the width L2 of the permanent magnet 6 and here it represents less than 25% of the width L2 of the permanent magnet 6.

[0097] It goes without saying that the invention is not limited to the embodiments described above as examples; on the contrary, it encompasses all variant embodiments.

Claims

Claims 1. Electric machine rotor comprising: - a rotor body (7), formed by a stack of sheets, preferably configured to be positioned on a rotor shaft, and - a plurality of pairs of magnetic poles (P) distributed circumferentially on the rotor body (7), each magnetic pole (P) comprising at least one flux barrier, preferably at least two flux barriers located radially above each other, each flux barrier comprising at least one recess (1), each magnetic pole (P) comprising at least one permanent magnet (6) in a recess (1), characterized in that each recess (1) in which a permanent magnet (6) is inserted further comprises a groove (4), the groove (4) being filled with adhesive component (5) for fixing the permanent magnet (6) in the recess (1).

2. Rotor according to claim 1, wherein the groove has a predefined maximum depth (Lp), preferably the groove (4) being defined by a rounded arcuate profile or by a groove.

3. Rotor according to one of the preceding claims for which the width (L) of the groove (4) is less than 50% of the width (L2) of the permanent magnet (6).

4. Rotor according to one of the preceding claims, in which the predefined maximum depth (Lp) is between 0.5 and 2 mm, preferably between 0.8 and 1.2 mm.

5. Rotor according to one of the preceding claims, wherein the groove (4) is positioned on the surface of the recess closest to the axis of rotation of the rotor (2).

6. Rotor according to one of the preceding claims, in which the permanent magnets (6) are prismatic or non-prismatic.

7. Rotor according to one of the preceding claims, in which each magnetic pole (P) comprises a single flux barrier comprising two lateral recesses (1), each lateral recess (1) comprising a prismatic permanent magnet (6).

8. Rotor according to one of the preceding claims, in which each recess (1) comprises several grooves (4), each groove (4) being filled with adhesive component (5).

9. Electrical machine comprising a stator and a rotor according to one of the preceding claims, said rotor being housed inside said stator.

10. Electric machine according to claim 9, wherein said electric machine is of the synchro-reluctant electric machine type.

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