ROTOR OF AN ELECTRICALLY TURNING MACHINE AND ROTATING ELECTRIC MACHINE

Description

[0001] The invention relates to a rotor of a rotating electrical machine and a rotating electrical machine equipped with such a rotor.

[0002] Known from patent applications WO 2014 / 082839 A2, WO 2017 / 076461 A1, EP 2 696 470 A2, DE 10 2016 218 540 A1 and US2015 / 0364959A1 is a rotor for a rotating electrical machine, capable of interacting with a stator of the rotating electrical machine and rotating relative to an axis of rotation, the rotor comprising: a rotor body comprising a cavity, a permanent magnet disposed in the cavity, the permanent magnet having a first length in the direction of the axis of rotation, the rotor body comprising a magnet holding portion on which the permanent magnet rests and capable of facing the stator, the magnet holding portion having a second length in the direction of the axis of rotation between a first face of the holding portion and a second face of the holding portion, the first length of the permanent magnet being equal to or less than the second length of the holding portion.

[0003] Such a rotor has the disadvantage of generating magnetic losses between the permanent magnet and the stator. Indeed, the permanent magnet used often includes softened edges at its ends, for example with a fillet. These softened edges are linked to manufacturing constraints of permanent magnets. Permanent magnets with such softened edges have the effect of locally increasing the air gap between the rotor and the stator. This increase in the air gap has the disadvantage of increasing magnetic losses and therefore reducing the power of the electrical machine.

[0004] The present invention aims to eliminate all or part of these drawbacks.

[0005] The invention relates to a rotor for a rotating electrical machine according to the claim capable of interacting with a stator of the rotating electrical machine and rotating relative to an axis of rotation, the rotor comprising: a rotor body comprising a cavity, a permanent magnet partially disposed in the cavity, the permanent magnet having a first length in the direction of the axis of rotation between a first face of the permanent magnet of a first end of the permanent magnet and a second face of the permanent magnet of a second end of the permanent magnet, the rotor body comprising a permanent magnet holding portion on which the permanent magnet rests and capable of being radially opposite the stator, the permanent magnet holding portion having a second length in the direction of the axis of rotation between a third face of the holding portion and a fourth face of the holding portion, the first length of the permanent magnet being greater than the second length of the holding portion.

[0006] Using a permanent magnet longer than the holding portion of the rotor body improves the performance of the rotating electrical machine in which the rotor is mounted. Permanent magnets have, at their ends, a junction surface between two surfaces, for example between two flat surfaces. The junction surface is, for example, a fillet or a chamfer. Using a magnet longer than the holding portion of the rotor body allows all or part of this junction surface to be offset outside the holding portion. This reduces or even avoids an apparent increase in the air gap between the stator and the rotor at the ends of the rotor body. Magnetic losses are therefore reduced and the performance of the rotating electrical machine is improved.

[0007] According to a characteristic of the invention, the first end of the permanent magnet protrudes, by a third length in the direction of the axis of rotation, from the cavity relative to one of the third face of the holding part and the fourth face of the holding part.

[0008] According to an additional characteristic of the invention, the second end of the permanent magnet protrudes, by a fourth length in the direction of the axis of rotation, from the cavity relative to the other of the third face of the holding part and fourth face of the holding part.

[0009] A permanent magnet protruding at these two ends of the holding part of the rotor body allows a reduction in magnetic losses at the ends and therefore a greater improvement in the performance of the rotating electrical machine.

[0010] The third length and the fourth length are equal or different.

[0011] According to a characteristic of the invention, the rotor comprises a first closing flange, the first closing flange comprising a first housing receiving the first end of the permanent magnet.

[0012] The use of such a first flange facilitates the manufacture of the rotor. Indeed, since the first housing is made in the flange prior to the assembly of the rotor, a wide variety of materials can be used for the production of the first flange. For example, it is not necessary to heat the rotor during its assembly. This possible absence of heat input prevents deformation of the rotor parts and demagnetization of the magnets during assembly.

[0013] According to a characteristic of the invention, the rotor comprises a second closing flange. The second closing flange may comprise a second housing receiving the second end of the permanent magnet.

[0014] The use of closing flanges makes it possible to hold the rotor body together, particularly when it is formed by a stack of sheets. To ensure this holding, a fixing means, consisting of a screw and nut assembly, allows the first closing flange and second closing flange to be fixed to the rotor body.

[0015] In addition, the end plates can be used to balance the rotor, particularly by removing material from the end plates. The housings in the end plates accommodate the ends of the permanent magnet.

[0016] The housings can be sized to avoid contact with the permanent magnet when assembling the end plates. This means the permanent magnet is not constrained when assembling the end plates.

[0017] According to an additional characteristic of the invention, the holding part comprises a tooth circumferentially oriented relative to the axis of rotation to radially hold the permanent magnet.

[0018] According to an additional characteristic of the invention, the first end of the permanent magnet comprises a first junction face, in particular a fillet, between a fifth face of the permanent magnet held by the holding part and the first face of the permanent magnet,

[0019] the first joining face facing the stator and extending over a fifth length in the direction of the axis of rotation, the fifth length being between 0.5 and 2 times the third length, in particular between 0.6 and 1.5 times the third length.

[0020] The use of a fifth length between 0.5 and 2 times the third length, in particular between 0.6 and 1.5 times the third length, makes it possible to ensure an improvement in the performance of the rotating electrical machine while limiting an increase in the axial size of the rotor.

[0021] According to an additional characteristic of the invention, the second end of the permanent magnet comprises a second junction face, in particular a fillet, between a fifth face of the permanent magnet held by the holding part and the second face of the permanent magnet,

[0022] the second joining face facing the stator and extending over a sixth length in the direction of the axis of rotation, the sixth length being between 0.5 and 2 times the fourth length, in particular between 0.6 and 1.5 times the fourth length.

[0023] The use of a sixth length of between 0.5 and 2 times the fourth length, in particular between 0.6 times and 1.5 times the fourth length, makes it possible to ensure an improvement in the performance of the rotating electrical machine while limiting an increase in the axial size of the rotor. According to an additional characteristic of the invention, the permanent magnet is a ferrite type permanent magnet.

[0024] According to an additional characteristic of the invention, the permanent magnet is held in the cavity by a varnish or glue.

[0025] The invention also relates to a rotating electrical machine comprising: a rotor as described previously, a stator.

[0026] According to an additional characteristic of the invention, the rotor is radially, relative to the axis of rotation, inside the stator.

[0027] The rotating electrical machine may comprise a power electronic component, capable of being connected to the on-board network of a vehicle. This power electronic component comprises, for example, an inverter / rectifier allowing, depending on whether the electrical machine operates as a motor or a generator, to charge an on-board network of the vehicle or to be electrically powered from this network.

[0028] The rotating electrical machine may also include a pulley or any other means of connection to the rest of the vehicle's powertrain. The electrical machine is, for example, connected, in particular via a belt, to the crankshaft of the vehicle's thermal engine. Alternatively, the electrical machine is connected to other locations in the powertrain, for example, at the input of the gearbox from the point of view of the torque transmitted to the vehicle's wheels, at the output of the gearbox from the point of view of the torque transmitted to the vehicle's wheels, at the gearbox from the point of view of the torque transmitted to the vehicle's wheels, or even on the front axle or the rear axle of this powertrain.

[0029] The invention may be better understood by reading the following description of non-limiting examples of its implementation and by examining the attached drawing in which: there figure 1 represents a partial sectional view of a rotating electrical machine comprising a rotor according to the invention, the figure 2 represents a partial sectional view of the rotor of the rotating electrical machine of the figure 1 , there figure 3 represents another partial sectional view of the rotor of the rotating electrical machine of the figure 1 , there figure 4 represents a closing flange of the rotor of the rotating electrical machine of the figure 1 , there figure 5 represents another partial sectional view of the rotor of the rotating electrical machine of the figure 1 , there figure 6 represents a magnet of the rotor of the rotating electric machine of the figure 1 .

[0030] In all the figures, identical elements or elements performing the same function have the same reference numbers. The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment or that the features apply only to a single embodiment. Single features of different embodiments may also be combined or interchanged to provide other embodiments.

[0031] There figure 1 represents a partial view of an electric machine with rotation axis A. For better readability, some parts have not been shown.

[0032] The electric machine consists of a rotor 1 and a stator 3.

[0033] The stator 3 comprises, for example, a stator body 8 and phase windings 9.

[0034] Rotor 1 includes: a rotor body 7 comprising a cavity 10, a permanent magnet 4 partially arranged in the cavity 10.

[0035] Permanent magnet 4 is for example a ferrite type permanent magnet.

[0036] In another embodiment the permanent magnet is a rare earth type magnet.

[0037] In another embodiment, the permanent magnet comprises a set of magnets assembled together. The magnets assembled together may be of different types, for example, ferrite type and rare earth type.

[0038] The permanent magnet 4 comprises a first face 11 at a first end 14 of the permanent magnet 4 and a second face 12 at a second end 15 of the permanent magnet 4. A first length 13 is defined, in the direction of the axis of rotation A between the first face 11 and the second face 12. The first face 11 and the second face 12 are for example parallel.

[0039] The rotor body 7 comprises, for example, a stack of magnetic sheets. The rotor body may be mounted on a shaft not shown in the figures.

[0040] As shown in the figure 2 , the rotor body 7 comprises a holding portion 16 for the permanent magnet 4. The permanent magnet 4 bears on the holding portion 16. The permanent magnet 4 may bear on the holding portion directly or indirectly. It is for example achieved by means of a plate 29 or a laminate. Such a plate 29 is made of a more flexible material than the permanent magnet 4. The plate 29 is for example made of a plastic or composite material, in particular a resin filled with glass fibers. The plate 29 is positioned between the holding portion 16 and the permanent magnet 4. The plate 29 makes it possible to improve the contact between the holding portion 16 and the permanent magnet 4.

[0041] The holding part comprises, for example, a tooth 26 of circumferential orientation relative to the axis of rotation A to radially hold the permanent magnet 4. The support of the permanent magnet 4 on the holding part can then be carried out on one face of the tooth 26.

[0042] In another embodiment not shown, the holding part is circumferentially continuous. The permanent magnet is then said to be buried.

[0043] In the embodiment shown in the figures, the rotor comprises a plurality of permanent magnets 4, each arranged in a different cavity 10. Each permanent magnet is held by two teeth 26 of opposite circumferential directions. The cavity 10 is open radially between the two teeth 26.

[0044] The holding portion 16 of the permanent magnet 4 is radially opposite the stator 3. The holding portion 16 extends over a second length 19 in the direction of the axis of rotation A between a third face 17 of the holding portion and a fourth face 18 of the holding portion.

[0045] The plate 29 has, for example, a length greater than or equal to the second length.

[0046] The first length 13 of the permanent magnet 4 is greater than the second length 19 of the holding part 16.

[0047] The first end 14 of the permanent magnet 4 protrudes, by a third length 20 in the direction of the axis of rotation A, from the cavity 10 relative to one of the third face 17 of the holding part 16 and fourth face 18 of the holding part 16.

[0048] Furthermore, the second end 15 of the permanent magnet 4 may protrude, by a fourth length 21 in the direction of the axis of rotation A, from the cavity 10 relative to the other of the third face 17 of the holding part 16 and fourth face of the holding part 16. Thus the permanent magnet protrudes at both ends 14, 15 of the holding part.

[0049] The rotor body 7 may have a length equal to the second length 19 of the holding portion 16. As seen previously, the rotor body may comprise a stack of sheets. Each of the sheets, of similar shape, may then comprise a fraction of the tooth 26.

[0050] As shown in the figure 1 , the rotor 1 may comprise a first closing flange 22. The first closing flange 22 comprises a first housing 23 receiving the first end 14 of the permanent magnet 4.

[0051] Furthermore, the rotor 1 may comprise a second closing flange 24. The second closing flange 24 comprises a second housing 25 receiving the second end 15 of the permanent magnet 4.

[0052] The first closing flange 22 and second closing flange 24 can provide a balancing disc function for the rotor 1. Balancing is carried out, for example, by removing material from the first closing flange 22 and / or second closing flange 24.

[0053] The first closing flange 22 and second closing flange 24 are for example made of a low-magnetic material, in particular aluminum, to avoid magnetically short-circuiting the rotor 1.

[0054] There figure 4 represents one of the first closing flange 22 and second closing flange 24. A fixing means 6 can allow the fixing of the first closing flange 22 and second closing flange 24 on the rotor body 7. According to the invention and as shown in the figures, the fixing means 6 is a set of screws and nuts. The rotor body 7 comprises first holes 27 (shown in the figure 2 ). The first closing flange 22 and second closing flange 24 comprise second holes 33. The first holes 27 and the second holes 33 allow the passage of the rod of the screws of the fixing means 6. Tightening the nut of the fixing means 6 on the screw allows the stator body 7 to be clamped between the first closing flange 2 and the second closing flange 24.

[0055] There figure 5 represents a partial schematic view of the detail of the permanent magnet 4 and of the holding part 16 of the rotor 1 shown in the figure 3 . To facilitate understanding of the figure 5 , plate 29 was not represented.

[0056] The first end 14 of the permanent magnet 4 comprises a first junction face 30 between a fifth face 28 of the permanent magnet 4 held by the holding part 16, in particular the tooth 26, and the first face 11 of the permanent magnet. The first junction face 30 is, for example, a fillet.

[0057] The fifth face 28 of the permanent magnet 4 is for example flat. Similarly the first face 11 of the permanent magnet is for example flat.

[0058] There figure 6 represents the permanent magnet 4 with the first junction face 30.

[0059] The first junction face 30 faces the stator 8 and extends over a fifth length 31 in the direction of the axis of rotation A. The fifth length 31 is for example between 0.8 and 1.2 times the third length 20.

[0060] Similarly, the second end 15 of the permanent magnet 4 comprises a second junction face 34, in particular a fillet, between the fifth face 28 of the permanent magnet 4 held by the holding part 16 and the second face 12 of the permanent magnet 4.

[0061] The second face 12 of the permanent magnet 4 is for example flat.

[0062] The second joining face 34 faces the stator 8 and extends over a sixth length in the direction of the axis of rotation A. The sixth length is between 0.8 and 1.2 times the fourth length 21.

[0063] In another embodiment not shown, the first and / or the second joining face is a chamfer.

[0064] The permanent magnet 4 may be held in the cavity by a varnish or an adhesive. The first closing flange 22 and second closing flange 24 may comprise an opening 32 to allow the introduction of the glue or the varnish. The opening 32 is for example made in the first closing flange and the second closing flange respectively, in particular in the first housing and the second housing respectively.

[0065] In the embodiment shown in the figures, the rotating electrical machine is a rotating electrical machine with an internal rotor 1, that is to say a rotating electrical machine in which the rotor 1 is radially, relative to the axis of rotation A, inside the stator 3.

[0066] In other embodiments of the invention, the rotating electrical machine is an external rotor rotating electrical machine, i.e. a rotating electrical machine in which the rotor is radially, relative to the axis of rotation, outside the stator.

Claims

1. A rotor (1) for a rotating electrical machine, capable of interacting with a stator (3) of the rotating electrical machine and rotating about an axis of rotation (A), the rotor (1) comprising: a. a rotor body (7) having a cavity (10), b. a permanent magnet (4) partially disposed in the cavity (10), the permanent magnet (4) having a first length (13) in the direction of the axis of rotation (A) between a first face (11) of the permanent magnet (4) at a first end (14) of the permanent magnet (4) and a second face (12) of the permanent magnet (4) at a second end (15) of the permanent magnet (4), c. the rotor body (7) comprising a permanent magnet holding portion (16) on which the permanent magnet (4) rests and which is capable of being radially opposite the stator (3), the permanent magnet holding portion (16) having a second length (19) in the direction of the axis of rotation (A) between a third face (17) of the holding portion and a fourth face (18) of the holding portion, the first length (13) of the permanent magnet (4) being greater than the second length (19) of the holding portion (16), d. the first end (14) of the permanent magnet (4) protruding, by a third length (20) in the direction of the axis of rotation (A), from the cavity (10) relative to one of the third face (17) of the holding part (16) and the fourth face (18) of the holding part (16), and the rotor (1) being characterized in that it comprises: a first closure flange (22), the first closure flange (22) comprising a first housing (23) receiving the first end (14) of the permanent magnet (4) and a second closure flange (24), and in that the rotor body (7) comprises first holes (27), the first and second closure flanges (22, 23) comprise second holes (33), the first and second holes (27, 33) allowing the passage of a fastening means (6) composed of a set of screws and nuts.

2. Rotor (1) according to the previous claim, in which the second end (15) of the permanent magnet (4) protrudes, by a fourth length (21) in the direction of the axis of rotation (A), of the cavity (10) relative to the other of the third face (17) of the holding part (16) and the fourth face of the holding part (16).

3. Rotor (1) according to claim 2, wherein the second closure flange (24) comprises a second housing (25) receiving the second end (15) of the permanent magnet (4).

4. Rotor (1) according to one of the preceding claims, wherein the holding portion (16) comprises a tooth (26) oriented circumferentially with respect to the axis of rotation (A) to radially hold the permanent magnet (4).

5. Rotor (1) according to one of the preceding claims, wherein the first end (14) of the permanent magnet (4) comprises a first junction face (30), namely a fillet, between a fifth face (28) of the permanent magnet (4) held by the holding portion (16) and the first face (11) of the permanent magnet (4), the first junction face (30) facing the stator (8) and extending over a fifth length (31) in the direction of the axis of rotation (A), the fifth length (31) being between 0.5 and 2 times the third length (20), in particular between 0.6 and 1.5 times the third length (20).

6. Rotor (1) according to one of claims 2 to 5, in which the second end (15) of the permanent magnet (4) comprises a second junction face (34), in particular a fillet, between a fifth face (28) of the permanent magnet (4) held by the holding part (16) and the second face (12) of the permanent magnet (4), the second junction face (34) facing the stator (8) and extending over a sixth length in the direction of the axis of rotation (A), the sixth length being between 0.5 and 2 times the fourth length (21), in particular between 0.6 and 1.5 times the fourth length.

7. Rotor (1) according to one of the preceding claims, wherein the permanent magnet (4) is a ferrite-type permanent magnet.

8. Rotor (1) according to one of the preceding claims, wherein the permanent magnet (4) is held in the cavity (10) by a varnish or an adhesive.

9. Rotating electric machine comprising: a. a rotor (1) according to one of the preceding claims, b. a stator (3).

10. Electric machine according to claim 9, wherein the rotor (1) is radially, with respect to the axis of rotation, inside the stator (3).