Electric machine rotor with a recess including a groove filled with adhesive component for attaching a permanent magnet

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). Furthermore, each recess (1) in which a permanent magnet (6) is inserted has a groove (4), the groove (4) being filled with adhesive for fixing the permanent magnet (6) in the recess (1). Figure 5 to be published

Description

Title of the invention: Electric machine rotor with a recess comprising a groove filled with adhesive component for attaching a permanent magnet technical field

[0001] The present invention relates to a rotating synchronous-reluctant (assisted by permanent magnets) or buried magnet electric machine and relates more particularly to the particular architecture of a rotor of such a machine.

[0002] Generally, such an electrical machine comprises a stator and a rotor arranged coaxially one inside the other.

[0003] The rotor is formed 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 allowing the magnetic flux from the magnets to be directed 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.

[0004] This rotor is generally housed inside a stator which carries electrical windings to generate a magnetic field to drive the rotor in rotation. Previous technique

[0005] As is better described in particular in patent application WO2020 / 020580, the rotor of a synchronous reluctance machine comprises a plurality of axial recesses which pass through the laminations from one side to the other.

[0006] For the rotor design described in this patent application, a first series of axial recesses, arranged radially one above the other and at a distance from each other, form housings for magnetic flux generators, here permanent magnets in the form of a rectangular bar.

[0007] The other series of recesses consists of perforations in an inclined radial direction, which start from these housings to reach the vicinity of the edge of the sheets, in the vicinity of the air gap.

[0008] The inclined perforations are arranged symmetrically with respect to the magnet housings so as to form, in each case, a geometric figure substantially in the shape of a flattened V, with the flat bottom formed by the magnet housing and the inclined arms of this V formed by the perforations. This creates flux barriers formed by the perforations. The magnetic flux from the permanent magnets can then only pass through the solid parts between the perforations. solid parts are made of a ferromagnetic material.

[0009] As is known, permanent magnets are held in position within the rotor recesses by means of adhesive (also called resin or any other adhesive component that holds the permanent magnet in position within the recess). The recess into which a permanent magnet is inserted is then filled with adhesive, meaning that the volume of the recess containing the permanent magnet(s) is either filled by the permanent magnet itself or by the adhesive, which then fills the space in the recess free of permanent magnets (in other words, the permanent magnet is embedded in the adhesive within the recess into which it is inserted). Consequently, removing the permanent magnet for repair or separating the permanent magnet from the rotor body, particularly for recycling, at best results in damage to the permanent magnet, or at worst makes it impossible to extract it from the rotor.This constitutes a major obstacle for the electrical machine recycling industry, and more specifically 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 providing increased performance density and thus a reduction in other materials composing 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 range.

[0010] US patent application 2013 / 270954 AA, which relates to an electric machine rotor, is known. The rotor of this electric machine comprises a rotor body and permanent magnets located on the surface of the rotor body (and not embedded within it). Grooves are formed on the surface of the rotor body in contact with the permanent magnets to increase the magnetic force that secures the magnets to the rotor body. Furthermore, adhesive may be applied to the interface between the rotor body and the permanent magnets. However, the adhesive force is applied over the entire interface surface. Consequently, removing the permanent magnets is difficult. Moreover, the permanent magnets of this machine are located on the surface of the rotor.However, the solutions suitable for this machine topology cannot be directly transposed to a magnet-assisted synchronous-reluctant machine topology or to a machine with buried magnets.

[0011] To improve the recyclability of electrical machines, and more specifically of 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 reused in the production of electrical machines. It is therefore necessary to improve the method of holding the magnet in position by making it removable. Summary of the invention

[0012] The invention relates to an electric machine rotor comprising: - a rotor body, formed by a stack of laminations, preferably configured to be positioned on a rotor shaft, and - 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.

[0013] In addition, each recess in which a permanent magnet is inserted further has a groove, the groove being filled with adhesive component for fixing the permanent magnet in the recess.

[0014] According to an advantageous embodiment, the groove has a predefined maximum depth, preferably, the groove being defined by a rounded profile in an arc of a circle or by a groove.

[0015] Preferably, the width of the throat is less than 50% of the width of the permanent magnet.

[0016] Advantageously, the maximum predefined depth is between 0.5 and 2 mm, preferably between 0.8 and 1.2 mm.

[0017] According to one embodiment of the invention, the groove is positioned on the surface of the recess closest to the axis of rotation of the rotor.

[0018] Depending on a configuration, permanent magnets are prismatic or non-prismatic.

[0019] Advantageously, each magnetic pole comprises a single flux barrier comprising two lateral recesses, each lateral recess comprising a prismatic permanent magnet.

[0020] Preferably, each recess comprises several grooves, each groove being filled with adhesive component.

[0021] The invention also relates to an electrical machine comprising a stator and a rotor as described, said rotor being housed inside said stator.

[0022] Advantageously, said electrical machine is of the synchronous-reluctant electrical machine type. List of figures

[0023] Other features and advantages of the rotor and the electric machine according to the invention will become apparent from the following description of non-limiting examples of embodiments, with reference to the figures attached and described below. [Fig 1]

[0024] Fig. 1 represents an example of a flow barrier recess with a groove for the placement of the adhesive component, of a rotor for an electric machine according to the invention. [Fig 2]

[0025] Figure 2 represents a first embodiment of a glued assembly of a permanent magnet in a flux barrier recess with a groove for the adhesive component, of a rotor for an electric machine according to the invention. [Fig 3]

[0026] Figure 3 shows a second embodiment of a bonded 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. [Figure 4]

[0027] 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 flow barrier, of a rotor for an electric machine according to the invention. [Fig 5]

[0028] Figure 5 represents an embodiment of an electric machine rotor comprising several flux barriers with permanent magnets glued to each recess via a groove, according to the invention. Description of the implementation methods

[0029] The invention relates to a rotor for an electric machine, in particular for an electric machine, for example, of the type with buried magnets, and more particularly for a synchronous-reluctance machine assisted by permanent magnets. Furthermore, the present invention relates to an electric machine, preferably of the synchronous-reluctance type, comprising a rotor according to the invention and a stator, the rotor being arranged within the stator, preferably coaxially therewith.

[0030] Magnets that are inserted within the rotor itself are called "buried magnets", as opposed to surface magnets which 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 being generally called "air gap").

[0031] According to the invention, the electric machine rotor comprises: - a rotor body, formed by a stack of laminations, preferably configured to be positioned on a rotor shaft, and - a plurality of pairs of magnetic poles distributed circumferentially on the rotor body.

[0032] Each magnetic pole comprises at least one flux barrier, preferably at least two flux barriers located radially one above the other and Each flux barrier includes at least one recess. In addition, each magnetic pole includes at least one permanent magnet in a recess.

[0033] The recesses in the flow barriers are axial. In other words, the recesses extend in the axial (longitudinal) direction, that is, along the axis of the rotor, crossing the rotor over its entire axial length.

[0034] Permanent magnets generate a magnetic flux, enabling 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 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 (in particular torque and power) of the electric machine. A pair of magnetic poles comprises two magnetic poles of opposite polarity.

[0035] The recesses in which permanent magnets are inserted are completely embedded in the rotor body: in other words, the magnets are inserted (buried) within the rotor body and are not positioned on the surface of the rotor body. Thus, the performance of the electric machine is improved.

[0036] Furthermore, each recess into which a permanent magnet is inserted has at least one groove, this groove being filled with an adhesive component (in particular, a glue or a resin) for securing the permanent magnet in the recess. In other words, the recess comprises a shape for the insertion of 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 within 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 magnet's surface.Thanks to this reduced bonding surface (limited to at least one groove), the permanent magnet can be more easily removed, for example by local machining of the adhesive component or by applying distributed pressure to the visible surface of the magnet, which would constrain the adhesive component in shear. Therefore, the permanent magnet can be removed from the recess without damaging it.

[0037] 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.

[0038] The groove forms a hollow on the rotor body, allowing the glue to be placed in the groove.

[0039] According to an advantageous configuration, the adhesive used to hold the permanent magnet in the recess can be limited to the groove (or grooves): in other In short, the adhesive may only be applied within the groove(s). Therefore, there is no adhesive on the surface of the recess outside the areas where the grooves are located.

[0040] Advantageously, the adhesive surface (the surface of the groove at the interface with the permanent magnet) on the permanent magnet can be adapted to the level of vibrations expected on the rotor.

[0041] Advantageously, the groove can extend along the entire longitudinal length (along the rotor axis) of the rotor body. This ensures that the permanent magnet has an adhesive surface along its entire length in contact with the rotor body.

[0042] Advantageously, each recess can 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 over the entire axial length of the rotor body) and a lower surface (formed by the lower line and extending over the entire axial length of the rotor body).

[0043] The terms "upper" and "lower" extend radially with respect to the rotor axis. In other words, the upper line (the upper edge) and the upper surface of a recess is further from the rotor axis than the lower line (the lower edge) and the lower surface of the same recess.

[0044] According to one configuration of the invention, the groove can have a predefined maximum depth so as to optimize the adhesive force.

[0045] The predetermined maximum depth is understood to be the greater of the depth of the groove relative to the surface of the recess in which it is embedded. This maximum depth therefore corresponds to the maximum thickness of adhesive that can be placed between the bottom of the groove and the permanent magnet.

[0046] Advantageously, the groove (or at least one groove) can be defined by a rounded profile in the form of a circular arc (for example, with a predefined radius) and preferably, the groove can have a predefined maximum depth, or by a groove (of rectangular or square cross-section, for example, or substantially parallelepiped-shaped, preferably with rounded edges) of a predetermined maximum depth. This rounded profile or groove allows for easy production of the groove using industrial sheet metal cutting tools (for lamination) and ensures good cohesion through the adhesive bonding force.

[0047] According to one embodiment of the invention, the width of the groove (or the sum of the widths of the different grooves filled with glue) can be less than 50%, preferably less than 25% and even more preferably less than 10%, of the width of the permanent magnet.

[0048] By groove width, we mean 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 then the width of the groove at the interface with the permanent magnet.

[0049] The width of the permanent magnet is understood to be the dimension of the magnet in the direction parallel to the width of the throat. For a curved permanent magnet, the width can be considered as the length of the cord at the neutral line (also called the neutral fiber) of the permanent magnet.

[0050] 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 even more preferably less than 10% of the outer surface of the permanent magnet.

[0051] By limiting the bonding surface, dismantling the permanent magnet is facilitated and recycling it is made easier. Furthermore, the permanent magnet can be dismantled without damaging it.

[0052] According to a variant of the invention, the predefined maximum depth can be between 0.5 and 2 mm, preferably between 0.8 and 1.2 mm. Such a depth ensures a sufficient volume of adhesive to maintain the permanent magnet in position.

[0053] Alternatively, when the groove is a rectangular cross-section groove, the groove depth can be between 0.5 and 2 mm, preferably between 0.8 and 1.2 mm. Such a depth ensures a sufficient volume of adhesive to hold the permanent magnet in position.

[0054] According to one embodiment of the invention, the groove can be positioned on the surface of the recess closest to the rotor's axis of rotation (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 rotor's axis than the lower surface. This embodiment allows for easier implementation.

[0055] Preferably, the groove can be positioned on the surface of the recess furthest from the axis of rotation of the rotor (upper surface of the recess) to allow easier contact between the upper surface of the recess and the magnet by means of the centrifugal force which tends to naturally push the magnet towards the upper surface.

[0056] Advantageously, permanent magnets can be prismatic or non-prismatic. Prismatic permanent magnets allow for a simple embodiment of the invention. Non-prismatic magnets can be produced, for example, by machining, powder sintering techniques, or injection molding. Furthermore, non-prismatic magnets can be adapted to complexly shaped recesses, by example to recesses used to form concave flow barriers (whose median line, i.e. the middle line, is concave and preferably without discontinuities).

[0057] A "median line" is a line that is equidistant from the edges of the flux barrier (which respectively face the center and the periphery of the rotor), this median line is defined in a cross-section of the rotor (i.e. in a plane perpendicular to the axis of the rotor).

[0058] By a line "without discontinuities," it is understood 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 of a plurality of recesses separated, in particular, by at least one magnetic bridge, the median line also passes through the magnetic bridge. In other words, a magnetic bridge does not form a discontinuity in the median line.

[0059] According to an advantageous embodiment of the invention, each magnetic pole may comprise a single flux barrier including 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.

[0060] Preferably, each recess may include several grooves, each groove being filled with adhesive, for securing the permanent magnet within the recess. The use of several glue-filled grooves increases the adhesive strength and the bonding surface area between the rotor body and the permanent magnet. Increasing the adhesive strength is particularly advantageous in cases of expected high vibrations during operation. The adhesive can then be limited to the individual grooves: there is no adhesive outside the groove areas, thus facilitating the removal and recycling of the permanent magnet.

[0061] When several glue-filled grooves are placed on the same recess, the grooves can all be positioned on the surface of the recess closest to the rotor's axis of rotation (lower surface of the recess) or on the surface furthest from the rotor's axis of rotation (upper surface of the recess). Alternatively, at least one groove can be positioned on the surface of the recess closest to the rotor's axis of rotation (lower surface of the recess) and at least one other groove can be positioned on the surface of the recess furthest from the rotor's axis of rotation (upper surface of the recess).

[0062] Figure 5 illustrates, schematically and without limitation, a rotor for a machine electric according to the invention.

[0063] 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).

[0064] Each magnetic pole P shown in the figure comprises a single flux barrier (but could comprise several flux barriers positioned radially one above the other).

[0065] The magnetic flux barrier of each magnetic pole P here comprises two lateral recesses 1 and a permanent magnet 6 is inserted in 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.

[0066] Each lateral recess 1 is delimited by an upper surface 2 and a lower surface 3.

[0067] The upper surface 2 and lower surface 3 of the recesses are defined with respect to radial lines (represented by the dashed 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 the upper surface at a point 10. A surface is referred to as the upper surface when point 10 is located at a distance from the center C greater than the distance from point 11 to the center C. Conversely, a surface is referred to as the lower surface when point 11 is located at a distance from the center C less than the distance from point 10 to the center C.

[0068] The rotor body 7 is delimited by an internal diameter 8, suitable for engaging on a rotor shaft (not shown), and by an external diameter 9, suitable for entering the stator (not shown), which is coaxial with and surrounds the rotor. The stator and the rotor thus form an electrical machine, and more particularly a synchronous-reluctance electrical machine.

[0069] Each recess 1 into which a permanent magnet 6 is inserted includes a groove 4, which is filled with glue for retaining the permanent magnet 6 in the rotor body 7.

[0070] Apart from the glue-filled groove 4, the volume of the recess 1 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.

[0071] 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 include several grooves 4 implanted on the upper surface 2 and / or on the lower surface 3.

[0072] Fig. 1 illustrates, schematically and not in a limiting manner, an example of a recess with a groove in a rotor for an electric machine according to the invention.

[0073] The recess 1 shown comprises an upper surface 2 and a lower surface 3, which are parallel to each other (they could be non-parallel). As shown, the upper surface 2 and lower surface 3 are flat, and therefore the recess 1 is suitable for mounting prismatic permanent magnets. Of course, the upper surface 2 and lower surface 3 could be generated from curved lines, in particular concave lines, extending along the entire axial length of the rotor body, so as to accommodate non-prismatic permanent magnets, thereby increasing the electromagnetic performance of the electric machine.

[0074] The recess 1 includes 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.

[0075] The groove 4 is a rounded profile, forming an arc of a circle, with a predetermined radius R and a 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 formed by a groove with a rectangular or square cross-section, in particular, or substantially parallelepiped-shaped, preferably with rounded edges. 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).

[0076] Furthermore, the width L of the throat at the interface with the permanent magnet forms a reduced bonding area, i.e. a bonding surface which represents less than 50% of the outer surface of the permanent magnet.

[0077] Fig. 2 illustrates, schematically and not in a limiting manner, a first example of mounting a permanent magnet 6 in a recess 1 of a rotor for an electric machine according to the invention.

[0078] The recess 1 shown comprises an upper surface 2 and a lower surface 3, which are parallel to each other here but could be otherwise. As shown, the upper surface 2 and lower surface 3 are flat, and therefore the recess 1 is suitable for mounting prismatic permanent magnets. Of course, the upper surface 2 and lower surface 3 could be generated from curved lines, in particular concave lines, extending along the entire axial length of the rotor body, so as to accommodate non-prismatic permanent magnets, allowing thus increasing the electromagnetic performance of the electrical machine.

[0079] The recess 1 includes 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, with a predetermined radius R and a 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 with a rectangular or square cross-section, in particular, or substantially parallelepiped-shaped, preferably with rounded edges.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 was positioned there) and then corresponds to the maximum distance between the bottom of the groove and the permanent magnet 6.

[0081] Furthermore, 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 area represents less than 50% of the surface

[0082] exterior, preferably less than 50% of the upper or lower surface on which the groove is implanted.

[0083] 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 put in the groove of the recess and then the permanent magnets inserted into the recess.

[0084] 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.

[0085] Fig. 3 illustrates, schematically and not in a limiting manner, a second example of mounting a permanent magnet 6 in a recess 1 of a rotor for an electric machine according to the invention.

[0086] The recess 1 shown comprises an upper surface 2 and a lower surface 3, which are parallel to each other (but could be otherwise). As shown, the upper surface 2 and lower surface 3 are planar, and therefore the recess 1 is suitable for mounting prismatic permanent magnets. Of course, the upper surface 2 and lower surface 3 could be generated from curved lines, including concave ones, extending along the entire axial length of the rotor body, so as to accommodate non-prismatic permanent magnets, thereby increasing the electromagnetic performance of the electric machine.

[0087] The recess 1 includes a groove 4 forming a hollow in the rotor body. Here, the groove 4 is positioned on the lower surface 3.

[0088] The groove 4 is a rounded profile, forming an arc of a circle, of predetermined radius R and of predetermined maximum depth Lp.

[0089] 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 formed by a groove with a rectangular or square cross-section, in particular, or substantially parallelepiped-shaped, preferably with rounded edges. 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 thus corresponds to the maximum distance between the bottom of the groove and the permanent magnet 6.

[0090] Furthermore, 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 or lower surface on which the groove is embedded.

[0091] The permanent magnet 6, here prismatic, is inserted into the recess 1 and glue 5 is placed in the groove 4 for holding the permanent magnet 6 in position in the recess 1.

[0092] 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.

[0093] [Fig.4] illustrates, schematically and not in a limiting manner, a permanent magnet with its bonding area according to the invention.

[0094] The permanent magnet 6 shown is prismatic but it could be of non-prismatic shape to increase the electromagnetic performance of the electrical machine.

[0095] The permanent magnet 6 is coated with glue 5 over 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 adhesive zone 5 is small and does not cover the entire outer surface of the magnet. The adhesive width L at the interface between the groove (where the adhesive is placed) and the permanent magnet 6 is less than the width L2 of the magnet. The adhesive width L of 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.

[0096] As can be understood, the invention is not limited to the embodiments described above by way of example, but on the contrary encompasses all variant embodiments.

Claims

Demands

1. An electric machine rotor comprising: - a rotor body (7), formed by a stack of laminations, 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 an adhesive component (5) for fixing the permanent magnet (6) in the recess (1), the groove having a predefined maximum depth (Lp), the predefined maximum depth (Lp) being between 0.5 and 2 mm.

2. Rotor according to claim 1, wherein the groove (4) is defined by a rounded profile in an arc of a circle or by a groove.

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

4. Rotor according to any one of the preceding claims, wherein the predefined maximum depth (Lp) is between 0.8 and 1.2 mm.

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

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

9. An electrical machine comprising a stator and a rotor according to one of the re- previous sales, the said rotor being housed inside the said stator.

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

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