Method for obtaining a rotor for a rotating electrical machine

Abstract

Title of the invention: Method for obtaining a rotor for a rotating electrical machine. The present invention relates to a method for obtaining a rotor (1) of a rotating electrical machine comprising a rotor body (2), a magnetic element, and a ring (6). The method comprises a step of positioning the rotor body (2) within an injection mold (42) and a step of placing the ring (6) within the injection mold (42) so that the ring (6) is positioned around the rotor body (2), as well as a step of injecting the magnetic element, in the form of a bonded magnet (4), between the rotor body (2) and the ring (6). Abstract figure: Figure 3

Description

Title of the invention: Method for obtaining a rotor for a rotating electrical machine

[0001] The present invention relates to the field of motor vehicles, and more particularly to the electrical machines equipping these motor vehicles.

[0002] Electric or hybrid motor vehicles are equipped with rotating electrical machines, in particular electric motors with at least one stator and one rotor. In some of these rotating machines, windings associated with the stator generate, when electrically powered, a magnetic flux which allows rotation of the rotor equipped with magnets. In a radial flux rotating machine, the magnetic flux is generated in a radial direction relative to an axis of rotation of the electric machine and the rotor rotates around this axis of rotation depending on the orientation of the radial magnetic field.

[0003] The rotors of these rotating machines conventionally comprise a hoop and a magnetic element. This hoop ensures that the magnetic element of the rotor is held in position, in particular by ensuring that it is held when the rotor rotates at high speed. The hoop comprises an inner radial wall, an outer radial wall and a bottom wall which delimit housings open on the top to receive portions of the magnetic element. The magnetic element is thus arranged within the hoop, against a bottom thereof.

[0004] The magnetic element is conventionally a solid magnet, which requires assembly operations to be secured to the hoop. However, both the arrangement of the magnetic element within the hoop and their securing to each other are complex operations. It is indeed difficult to control the dimensional tolerances between these two components. Furthermore, the manufacture of the rotor requires considerable time and investment, due to the multiplication of positioning and assembly operations.

[0005] The present invention falls within this context by proposing a method of manufacturing a rotor by which the production of the rotor is simplified, while reducing the number of operations required.

[0006] The main object of the present invention is thus a method for obtaining a rotor of a rotating electrical machine comprising a rotor body, a magnetic element and a hoop, the method of obtaining comprising the following steps: - positioning the rotor body within an injection mold; - placement of the hoop around the rotor body so as to form an annular chamber, - injection of the magnetic element, in the form of a bonded magnet, into the annular chamber.

[0007] The production method according to the invention corresponds to the manufacture of a rotor intended to be integrated into a rotating electrical machine and in particular into a radial flux rotating machine. The production method involves an injection mold having a cavity, within which a rotor body and a hoop are positioned in turn, respectively during a positioning step and a placement step. Either the rotor body positioning step occurs before the hoop placement step, or conversely the hoop placement step takes place prior to the rotor body positioning step. The rotor body is positioned as close as possible to a central pin of the injection mold while the hoop is placed along an external edge of this injection mold.The rotor body and the hoop are arranged so that they are not in contact with each other; in other words, after the positioning and placement steps, a space remains between these two components. Since the rotor body and the hoop are annular in shape, this space corresponds to an annular chamber.

[0008] Once the rotor body and the hoop are arranged in the mold, the production method comprises an injection step during which a magnetic element of the rotor, here a bonded magnet, is injected into the injection mold in the annular chamber between the rotor body and the hoop. The material constituting the bonded magnet then polymerizes to form, with the rotor body and the hoop, a set of secured components.

[0009] The use of injection makes it possible to easily manage the arrangement of the bonded magnet relative to those of the rotor body and the hoop. Indeed, the bonded magnet matches the shape of both the rotor body and the hoop. Injection also makes it possible to dispense with the bottom wall of the hoop, the bonded magnet being retained by the injection mold during the production process. Furthermore, injection makes it possible to combine positioning and assembly operations which were previously dissociated during the production of rotors of the prior art.

[0010] According to an optional feature of the invention, the rotor body comprises notches, a portion of the bonded magnet being inserted within the notches of the rotor body during the injection step.

[0011] The notches of the rotor body are cutouts which extend at least radially from an edge of the rotor body which is opposite the hoop. The notches are annular in shape. They extend, depending on the embodiments, over an entire circumference of the rotor body or over a portion of this circumference. When the bonded magnet is injected into the injection mold, it fills these notches.

[0012] According to an optional characteristic of the invention, the hoop comprises notches, a portion of the bonded magnet being inserted into the notches of the hoop during the injection step.

[0013] The notches of the hoop are cutouts which extend at least radially from a face of the hoop which is opposite the rotor body. The notches are not continuous along this internal face of the hoop; thus, there is a plurality of notches arranged at a distance from each other on the same circumference of the hoop inscribed in the internal face of the hoop opposite the rotor body. When the bonded magnet is injected into the injection mold, it fills these notches.

[0014] According to an optional characteristic of the invention, the production method comprises a step of pre-magnetization of the magnet linked within the injection mold, this pre-magnetization step involving coils arranged in the injection mold around a zone for placement of the hoop.

[0015] The coils are arranged equidistant from each other within the injection mold. Their orientation depends on the type of magnetization sought; thus, the coils will be straight, that is to say parallel to the axis of rotation of the rotor, for magnetization according to a Hallbach arrangement, or on the contrary they will be inclined relative to the axis of rotation of the rotor in the case of an inclined or twisted rotor. The purpose of the pre-magnetization step is to orient the magnetic charges of the bonded magnet formed from a polymer material in which particles or grains of magnetic material are embedded. These grains of magnetic material which participate in forming the bonded magnet are thus oriented according to field lines defined within the injection mold, which is in a magnetic field. When the polymer material constituting the bonded magnet polymerizes, the positions of its grains of magnetic material are fixed. The bonded magnet then has a fixed magnetic orientation..

[0016] According to an optional characteristic of the invention, the production method comprises a step of magnetizing the bonded magnet outside the injection mold.

[0017] The bonded magnet is remagnetized so as to give it a magnetic charge while respecting the previously defined orientations. For this purpose, the rotor body comprises indexing means making it possible to facilitate magnetization according to angular sectors defined during pre-magnetization.

[0018] The pre-magnetization and magnetization operations may take place at separate locations. For example, the pre-magnetization may be carried out at a supplier's location and the magnetization at a customer's location, with the bonded magnet then undergoing a demagnetization step between the pre-magnetization step and the magnetization step to facilitate its transportation.

[0019] The invention further relates to a rotor of a rotating electrical machine capable of being produced according to the production method as mentioned above, the rotor having an axis of rotation and comprising a rotor body and a hoop disposed around the rotor body so as to form an annular chamber, and a bonded magnet disposed in said annular chamber.

[0020] The rotor according to the invention is intended to be part of a rotating electrical machine, for example a radial flux motor, for installation within an electric or hybrid motor vehicle. The rotor body makes it possible to secure the linked magnet to a motor shaft element of the rotating electrical machine. The role of the hoop is to hold the linked magnet in position when the rotor rotates at high speed and to avoid a risk of bursting of the linked magnet.

[0021] The rotor body, the bonded magnet and the hoop are arranged in this order around the axis of rotation of the rotor, which is the result of the initial arrangement of the rotor body and the hoop within the injection mold.

[0022] According to an optional characteristic of the invention, the bonded magnet comprises tabs which extend in a plane perpendicular to the axis of rotation of the rotor within the rotor body and / or the hoop.

[0023] In other words, the tabs of the bonded magnet extend radially within the rotor body and / or the hoop.

[0024] According to an optional feature of the invention, the tabs of the bonded magnet extend within notches of the rotor body.

[0025] According to an optional characteristic of the invention, the tabs of the linked magnet extend within notches of the hoop.

[0026] The presence of a portion of the bonded magnet, namely its tabs, within the notches of the rotor body and / or the notches of the hoop makes it possible to limit sliding between the different elements of the rotor during operation of the rotating electrical machine.

[0027] According to an optional characteristic of the invention, the hoop has an annular shape.

[0028] In particular, the hoop according to the invention is, unlike the hoops of the prior art, devoid of a bottom. Such a bottom, the function of which is to retain the bonded magnet, is in fact not necessary since the bonded magnet is injected. Furthermore, during the production process, it is the injection mold which makes it possible to retain the bonded magnet.

[0029] According to an optional characteristic of the invention, the hoop comprises at least one collar, preferably openwork, partially covering the bonded magnet.

[0030] The collar corresponds to an excess thickness of the hoop which extends in the direction of the axis of rotation of the rotor.

[0031] In some embodiments, the collar is discontinuous along a periphery of the hoop, which facilitates the feasibility of the method for obtaining the rotor. This discontinuity is intended to block the rotation of the hoop on the bonded magnet during of the machine's operation. Alternatively, the collar extends around the entire circumference of the fret.

[0032] According to an optional characteristic of the invention, the bonded magnet has an axial end edge which helps to form an axial peripheral edge of the rotor.

[0033] The axial end edge delimits the bonded magnet in a direction parallel to the axis of rotation of the rotor. The axial peripheral edge delimits the rotor in a direction parallel to this axis of rotation of the rotor. It is understood that the bonded magnet is at least partially released within the rotor. In other words, the bonded magnet is not completely covered by the hoop, this hoop being devoid of a bottom wall.

[0034] According to an optional characteristic of the invention, the rotor body comprises a first portion intended to be in contact with a motor shaft element and a second portion in contact with the linked magnet, the rotor body comprising branches extending radially between the first portion and the second portion.

[0035] The first portion and the second portion have annular shapes. They are connected to each other by the branches of the rotor body. In sectional view along a plane perpendicular to the axis of rotation of the rotor, the branches extend in a star shape from the first portion. The presence of branches connecting the first portion and the second portion rather than a solid body makes it possible to limit the weight of the rotor body.

[0036] According to an optional characteristic of the invention, the bonded magnet is made from an alloy of rare earths or ferrites and a non-magnetic bonding material.

[0037] The rare earth alloy comprises, for example, neodymium, iron and boron. The non-magnetic material is in particular a resin such as a thermoplastic based on polyamide or polyphenylene sulfide.

[0038] The invention further relates to a rotating electrical machine comprising a rotor as mentioned above and at least one stator.

[0039] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and examples of embodiment given for informational and non-limiting purposes with reference to the appended drawings on the other hand, in which:

[0040] [Fig.l] schematically illustrates a rotor of a rotating electrical machine according to the invention, comprising a rotor body, a hoop and a bonded magnet having been injected between the rotor body and the hoop.

[0041] [Fig.2] illustrates, schematically and in isolation, the rotor body of [Fig.l];

[0042] [Fig.3] illustrates, schematically, an injection mold within which are arranged the rotor body, the hoop and the injected bonded magnet of [Fig.l].

[0043] The features, variants and different embodiments of the invention may be combined with each other, in various combinations, to the extent that they are not incompatible or mutually exclusive with respect to the others. In particular, it will be possible to imagine variants of the invention comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0044] In the figures, the elements common to several figures retain the same reference.

[0045] In the detailed description which follows, the terms “longitudinal”, “transverse” and “vertical” specify the orientation of the rotor for a rotating electrical machine according to the invention, these terms referring to a reference L, V, T illustrated in the figures.

[0046] Figures 1 to 3 thus illustrate, schematically, a rotor 1 according to the invention. This rotor 1 is intended to be integrated within a rotating electrical machine, for example a radial flux electric motor further comprising at least one stator, in order to equip a hybrid or electric vehicle, for example a car, a truck, a bicycle or an object which moves with its traction system such as a drone. Such a vehicle may further comprise an autonomous driving system.

[0047] The rotating electrical machine is capable of operating in an alternator mode to supply energy in particular to the battery and to the on-board network of the vehicle, and in an engine mode, not only to ensure the starting of the thermal engine of the vehicle, but also to participate in the traction of the vehicle alone or in combination with the thermal engine.

[0048] The power of the machine may be between 4kW and 50kW. Alternatively, the electric machine may be installed on an axle of the motor vehicle, in particular a rear axle. In the example considered, the electric machine advantageously has an operating voltage of less than 60 Volts, and preferably 48 Volts. Typically, the torque supplied by the electric machine is between 30N.m and 150N.m. Alternatively, the electric machine may have an operating voltage of more than 60V, or even more than 80V or more than 100V, in particular 300V or more. In the context of high voltage operation, the machine will typically have an operating voltage of between 400 and 800V, a power of up to 350kW and will provide a torque of up to 400N.m.

[0049] The rotor 1 comprises a rotor body 2, a magnetic element in the form of a bonded magnet 4 as well as a hoop 6. These constituent elements of the rotor 1 are arranged in this order around an axis of rotation X of the rotor 1.

[0050] The rotor body 2 is arranged around a motor shaft element 8 which is shown in [Fig.l]. The rotor body 2 is a metal element, for example made of steel. The rotor body 2 is composed of a first annular portion 10, a second annular portion 12 and branches 14 extending radially between the first portion 10 and the second portion 12. The first portion 10 surrounds the motor shaft element 8 while the second portion 12, of a larger diameter than the first portion 10, is arranged in contact with the linked magnet 4. Between the first portion 10 and the second portion 12, the branches 14 extend in a star shape; it is understood that between these branches, the rotor body 1 is devoid of material. The branches 14 are arranged at regular intervals between the first portion 10 and the second portion 12. The rotor body 2 here comprises eight branches 14, but it would be possible, without departing from the scope of the invention, to envisage a rotor body 2 having a different number of branches 14.

[0051] The branches 14 extend over an entire height of the rotor 1, such height being measured along the axis of rotation X of the rotor 1. In other words, the branches 14 extend from a first axial peripheral edge 16 of the rotor body 2 to a second axial peripheral edge 18 thereof, these axial peripheral edges 16, 18 being opposite in a direction parallel to the axis of rotation X of the rotor 1.

[0052] The rotor body 2 has notches 20, visible in [Fig. 2], which are formed within its second portion 12. The notches 20 are more precisely formed within a contact face 22 of the second portion 12 of the rotor body 2 which is intended to be opposite the linked magnet 4 and in contact with it.

[0053] The notches 20, which are particularly visible in [Fig. 2] in which the rotor body 2 is shown in isolation, extend from the contact face 22 in the direction of the axis of rotation X of the rotor 1. The notches 20 do not pass right through the second portion 12. The notches 20 comprise first notches 20A which extend axially, i.e. parallel to the axis of rotation X of the rotor 1, as well as second notches 20B which extend radially around the second portion 12, i.e. along a circumference of the rotor body 2. It is understood that the first notches 20A and the second notches 20B are perpendicular to each other. The grid of notches 20 which is thus formed within the rotor body 2 allows optimal coverage, but one could envisage another arrangement of the notches 20 without departing from the scope of the invention.

[0054] The rotor body 2 radially delimits the rotor 1 as close as possible to the axis of rotation X of the rotor 1 while the hoop 6 radially delimits the rotor 1 for its part furthest from this axis of rotation X. In other words, the rotor body 2 constitutes an internal radial end of the rotor 1 in the vicinity of the axis of rotation X and the hoop 6 constitutes an opposite external radial end of the rotor 1 at a distance from the axis of rotation X.

[0055] The hoop 6 is a non-magnetic annular element which is for example made of stainless steel or carbon. The hoop 6 comprises an external face 24 oriented towards an exterior of the rotor 1 and an internal face 26, radially opposite the external face 24, facing the linked magnet 4 and the rotor body 2.

[0056] The hoop 6 comprises notches 28 formed at least in its internal face 26. These notches 28 are here circumferentially separated from each other; in other words, they are not continuous along the hoop 6. As illustrated in [Fig. 3], the notches 28 are through-cut, that is to say they extend from the internal face 26 of the hoop to its external face 24. In an alternative embodiment not shown here, the notches 28 could extend radially over an entire circumference of the internal face 26, it being understood that they would then not be through-cut, that is to say they would only extend partially in the thickness of the hoop.

[0057] As can be seen in [Fig. 3], which is a sectional view in which both the notches 20 of the rotor body 2 and the notches 28 of the hoop 6 are visible, the second notches 20B and the notches 28 are arranged at different heights along a direction parallel to the axis of rotation X of the rotor 1. In other words, a given second notch 20B of the rotor body 2 is not arranged opposite a given notch 28 of the hoop 6.

[0058] As illustrated in Figures 1 and 3, the hoop 6 has at least one collar 30. This collar 30 extends the annular body of the hoop 6 in the direction of the axis of rotation X of the rotor 1. The collar 30 is arranged along a periphery 32 of the hoop 6. This periphery 32 corresponds to a rim which delimits the hoop 6 with respect to a direction parallel to the axis of rotation X of the rotor 1. There is thus a collar 30 for each of the peripheries 32 which delimit the hoop 6, that is to say at the level of the first axial peripheral edge 16 of the rotor 1 and at the level of its second axial peripheral edge 18.

[0059] As is particularly visible in [Fig.l], the collar 30 is here perforated, that is to say that it extends partially along the periphery 32. The collar 30 is here divided into three portions distributed at regular intervals around the periphery 32. However, without departing from the scope of the invention, embodiments could be envisaged in which the collar 30 would be continuous along the periphery 32.

[0060] The collar 30 partially covers the bonded magnet 4. The bonded magnet 4 has a generally annular shape. It extends radially between the contact face 22 of the second portion 12 of the rotor body 2 and the internal face 26 of the hoop 6 and it extends, along a direction parallel to the axis of rotation X of the rotor 1, between a first axial end edge 34 and a second axial end edge 36. Between the first axial end edge 34 and the second axial end edge 36, the bonded magnet 4 comprises a central zone 38. One of the collars 30 more particularly covers a portion of the first axial end edge 34 and the other of the collars 30 covers a portion of the second axial end edge 36. It is therefore understood that at the level of the collar 30, the linked magnet 4 has a height, measured along a direction parallel to the axis of rotation X of the rotor 1, less than a height of the linked magnet 4 measured in the vicinity of the rotor body 2.

[0061] Furthermore, due to the collar 30, a radial dimension of the first axial end edge 34 of the linked magnet 4 and / or a dimension of the second axial end edge 36, measured in a plane perpendicular to the axis of rotation X of the rotor 1 opposite the collar 30, is less than a dimension of the central zone 38 measured in this perpendicular plane.

[0062] As mentioned previously, the collar 30 only partially covers the bonded magnet 4. As a result, the bonded magnet 4 is uncovered, at least partially, within the rotor 1. In other words, with the exception of the collar 30, the first axial end edge 34 of the bonded magnet 4 forms the first axial peripheral edge 14 of the rotor 1 and the second axial end edge 36 of the bonded magnet 4 forms the second axial peripheral edge 16 of the rotor 1.

[0063] As is particularly visible in [Fig. 3], the bonded magnet 4 has tabs 40. The tabs 40 correspond to a point increase in a radial dimension of the bonded magnet 4 measured in a plane perpendicular to the axis of rotation X of the rotor 1. These tabs 40 extend radially from the central zone 38 of the bonded magnet 4, both in the direction of the rotor body 2 and the hoop 6. The tabs 40 are more precisely positioned within the notches 20 of the rotor body 2 and the notches 28 of the hoop 6. Such positioning of the tabs 40 results from the injection of the bonded magnet 4 into an annular chamber between the rotor body 2 and the hoop 6 during a production process which will now be detailed.

[0064] The method for obtaining the rotor 1 according to the invention results in the manufacture of a rotor 1 as described above. The method of obtaining requires the use of an injection mold 42 in the general shape of a rounded base cylinder. The injection mold 42 comprises an annular cavity which is delimited radially by a central pin 46 and by an annular rim 48. The cavity is delimited axially by a bottom wall 50 and by a cover 44. Windings 52 are arranged around the cavity, for example within the annular rim 48 as can be seen in [Fig. 3].

[0065] The production method begins with steps of manufacturing the rotor body 2 and the hoop 6. The rotor body 2 is for example made of steel, while the hoop 6 is made of stainless steel. Each of the rotor body 2 and the hoop 6 are manufactured so as to have their respective notches 20 and slots 28.

[0066] The method of obtaining comprises a step of positioning the rotor body 2 within the injection mold 42. The rotor body 2 is more precisely arranged against the bottom wall 50 and around the central pin 46 of the injection mold 42, the diameter of which is substantially identical to that of the drive shaft element 8 mentioned previously. Thus, the first portion 10 of the rotor body 2 is in contact with the central pin 46.

[0067] During a placement step, the hoop 6 is in turn arranged within the cavity of the injection mold 42, in contact with its bottom wall 50 and its annular rim 48. More precisely, the external face 24 of the hoop 6 is placed in contact with the annular rim 48. The method continues with a closing step during which the injection mold 42 is closed by the cover 44, which delimits a radial end of the rotor 1. The cover 44 rests on the rotor body 2 and on the hoop 6. It is understood from the above that the rotor body 2 and the hoop 6 are arranged at a radial distance from each other within the injection mold 42, so as to form an annular chamber between them. According to the invention, during an injection step the bonded magnet 4 is injected into this annular chamber between the rotor body 2 and the hoop 6.

[0068] The material composing the bonded magnet 4, here a rare earth alloy and a non-magnetic polymer material, is thus injected into the injection mold 42 using injection nozzles 54. The material composing the bonded magnet 4 is deposited against the bottom wall 50 of the cavity of the injection mold 42. It fills the annular chamber as well as the notches 20 of the rotor body 2 and the notches 28 of the hoop 6. The material composing the bonded magnet 4 is injected into the cavity of the injection mold 42 up to the level of the first axial peripheral edge 16 of the rotor 1, and opposite the collar 30 up to the periphery 32 of the hoop 6.

[0069] Once the bonded magnet 4 has been injected between the rotor body 2 and the hoop 6, the production method comprises a pre-magnetization step during which the coils 52 arranged within the annular rim 48 are electrically powered to orient magnetic charges of the bonded magnet 4. When the magnetic charges of the bonded magnet 4 are fixed, that is to say once the material composing the bonded magnet 4 has polymerized, the rotor body 2, the bonded magnet 4 and the hoop 6 form a single-piece assembly.

[0070] The rotor 1 thus formed can then be removed from the injection mold 42 and demagnetized for transport.

[0071] The obtaining method then comprises a step of assembling the rotor 1 to the motor shaft element 8, during which this motor shaft element 8 is inserted within the first portion 10 of the rotor body 2. The obtaining method can continue with a magnetization step which makes it possible to give the magnet linked 4 a magnetic charge according to the orientations determined during the previous pre-magnetization step. The magnetization step is facilitated by the presence of indexing means, here holes 56, which give an operator manufacturing the rotor 1 information concerning the orientation to be respected according to what was defined during the pre-magnetization step. The rotor 1 can then be associated with a stator in order to form a rotating electrical machine.

[0072] The present invention thus proposes a method for obtaining a rotor that is simplified in terms of the number of operations, the management of dimensional tolerances between a magnetic element and other components of the rotor being further facilitated.

[0073] The present invention cannot, however, be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically operative combination of such means.

Claims

Claims

1. Method for obtaining a rotor (1) of a rotating electrical machine comprising a rotor body (2), a magnetic element and a hoop (6), the method of obtaining comprising the following steps: - positioning the rotor body (2) within an injection mold (42); - placing the hoop (6) around the rotor body (2) so as to form an annular chamber; - injecting the magnetic element, in the form of a bonded magnet (4), into the annular chamber.

2. Method for obtaining a rotor (1) according to the preceding claim, in which the rotor body (2) comprises notches (20, 20A, 20B), a part of the bonded magnet (4) being inserted within the notches (20, 20A, 20B) of the rotor body (2) during the injection step.

3. Method for obtaining a rotor (1) according to any one of the preceding claims, in which the hoop (6) comprises notches (28), a part of the bonded magnet (4) being inserted within the notches (28) of the hoop (6) during the injection step.

4. Method for obtaining a rotor (1) according to any one of the preceding claims, comprising a step of premagnetizing the bonded magnet (4) within the injection mold (42), this premagnetization step involving several windings (52) arranged in the injection mold (42) around a zone for placing the hoop (6).

5. Method for obtaining a rotor (1) according to any one of the preceding claims, comprising a step of magnetizing the bonded magnet (4) outside the injection mold (42).

6. Rotor (1) of a rotating electrical machine capable of being produced according to the production method according to any one of the preceding claims, the rotor having an axis of rotation (X) and comprising a rotor body (2) and a hoop (6) arranged around the rotor body (2) so as to form an annular chamber, and a linked magnet (4) arranged in said annular chamber.

7. Rotor (1) according to the preceding claim, wherein the bonded magnet (4) comprises tabs (40) which extend in a plane perpendicular to the axis of rotation (X) of the rotor (1) within the rotor body (2) and / or the hoop (6).

8. Rotor (1) according to claim 7, wherein the tabs (40) of the bonded magnet (4) extend within notches (20, 20A, 20B) of the rotor body (2).

9. Rotor (1) according to any one of claims 7 to 8, in which the tabs (40) of the bonded magnet (4) extend within notches (28) of the hoop (6).

10. Rotor (1) according to any one of claims 6 to 9, in which the hoop (6) comprises at least one collar, preferably openwork, partially covering the bonded magnet (4).

11. Rotor (1) according to any one of claims 6 to 10, wherein the bonded magnet (4) has an axial end edge (34, 36) which participates in forming an axial peripheral edge (16, 18) of the rotor (1).

12. Rotor (1) according to any one of claims 6 to 11, in which the bonded magnet (4) is made from an alloy of rare earths or ferrites and a non-magnetic bonding material.

13. Rotating electrical machine comprising a rotor (1) according to any one of claims 6 to 12 and at least one stator.

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