Rotor assembly for an axial flux electric machine, particularly for motor vehicles, comprising a ventilation device for at least one fluid and an axial flux electric machine comprising it

Abstract

Title: Rotor assembly for an axial-flow electric machine, particularly for a motor vehicle, comprising a venting element for at least one fluid and an axial-flow electric machine comprising it. Rotor assembly (4) for an axial-flow electric machine (2) comprising a disk (44), at least one venting element (5) for at least one fluid and a shaft (41) comprising a base (40) configured to carry the disk (44), the at least one venting element (5) being at least partially connected to the disk (44) and / or the shaft (41) and the at least one venting element (5) comprising a base (51) and a plurality of vanes (52) arranged around the shaft (41). Abstract figure: Figure 3

Description

Title of the invention: Rotor assembly for an axial flux electric machine, particularly for motor vehicles, comprising a ventilation element for at least one fluid and an axial flux electric machine comprising it

[0001] The invention relates to a rotor assembly for an axial flux electric machine, particularly for a motor vehicle, comprising a ventilation device for at least one fluid. The invention also relates to an axial flux electric machine comprising such a rotor assembly. The invention further relates to an electric or hybrid vehicle equipped with the rotor assembly and / or the electric machine.

[0002] Electric or hybrid vehicles typically include at least one electric traction and / or propulsion machine, also called an electric motor, which propels the vehicle. The electric machine comprises, as is known, a rotor assembly including a shaft and rotating near a stator. Since the rotor assembly rotates at a high speed, the electric motor tends to heat up during operation and requires a cooling system. This need increases with the vehicle's power requirements.

[0003] In axial flux electric machines, it is known to cool the stator by means of oil. However, in order to limit the energy losses due to the bubbling of the rotor in the oil, the latter is conventionally isolated from an oil circulation zone by means of a sealed membrane bonded to the stator and extending partly into the air gap, i.e. in the space between the stator and the rotor assembly.

[0004] For the most powerful axial flux electric machines, known as high-performance machines, capable of delivering power outputs exceeding one hundred kilowatts, it is also necessary to dissipate heat from the rotor assembly, particularly from the magnet blocks forming a disc. Indeed, at high rotational speeds, especially around 10,000 rpm, the disc generates significant air shear at the air gap, which tends to heat the disc and the nearby diaphragm. It is therefore essential to ensure the cooling of the rotor assembly, both to reduce energy losses and to preserve the integrity of the sealed diaphragm's mounting.

[0005] Conventionally, it is known to integrate into the electric machine an airflow circuit that passes at least partially through the rotor assembly. Such an airflow can be directed to an internal volume of the electric machine via at least one air inlet located in a housing of the electric machine or via a bore located in the shaft. Such arrangements, however, have limited pumping or ventilation capacity for the airflow. For example, the airflow is propelled into the electric machine via a circuit including, in particular, an air pump. Such a solution, however, has the disadvantage of being very bulky and not allowing for homogeneous cooling of the rotor assembly.

[0006] The present invention falls within this context and aims to provide an alternative to known axial flux electric machines to ensure thermal management of the rotor by optimizing the circulation, and in particular the ventilation capacity, of at least one cooling fluid of the rotor assembly.

[0007] The invention relates to a rotor assembly for an axial flux electric machine, in particular for a motor vehicle, comprising a disc, at least one ventilation element for at least one fluid and a shaft comprising a base configured to carry the disc: - the disc and the shaft comprising respectively a plurality of primary holes and a plurality of secondary holes suitable for receiving means of fixing the disc onto the shaft; - at least one ventilation element being at least partly connected to the disc and / or the shaft and at least one ventilation element comprising a base and a plurality of blades, in particular at least partly connected to the base, arranged around the shaft and extending transversely and projecting from the base.

[0008] In particular, the lamellae are regularly arranged around the shaft and / or relative to at least one of the plurality of primary holes and the plurality of secondary holes.

[0009] Optionally: - the base of at least one ventilation component is attached and fixed to the disc or the base of the shaft; or - the base of at least one ventilation element forms a single unit with the disc or with the base of the shaft.

[0010] According to examples of implementation: - the base of at least one ventilation component comprises a plurality of washers, comprising a plastic or metallic material, suitable for receiving fastening means; and / or - at least some of the slats of the plurality of slats are attached and fixed to the base of at least one ventilation element.

[0011] Optionally: - at least some of the lamellae (52) of the plurality of lamellae (52) are curved; and / or - at least part of the lamellae (52) of the plurality of lamellae (52) are at least partly straight.

[0012] In particular, at least one ventilation element comprises a plastic material, in particular filled, and / or a metallic material and / or a composite material.

[0013] According to an optional embodiment, the rotor assembly comprises a plurality of ventilation elements for at least one fluid, the at least one ventilation element, hereinafter referred to as the first ventilation element, being connected to one of the shaft or disc and a second ventilation element being connected to the other of the shaft or disc.

[0014] Optionally, the rotor assembly further comprises a plurality of means for fixing the disc to the shaft, each comprising a head: - at least some of the slats of the plurality of slats being connected by the fastening means; and / or - the rotor assembly including, in addition, at least one cap attached and disposed at the level of the head of at least one of the fixing means at least one blade being connected to at least one cap.

[0015] The invention also relates to a ventilation element for a rotor assembly according to the invention, comprising a base and a plurality of blades directly or indirectly connected to the base. In particular, said blades are configured to be arranged around the shaft and to extend transversely and project from the base.

[0016] The invention also extends to an axial flux electric machine, in particular for a motor vehicle, comprising a stator, including a housing delimiting an internal volume, and a rotor assembly and / or a ventilation device according to the invention.

[0017] The invention can further be extended to an arrangement, in particular for a motor vehicle, comprising an electrical machine according to the invention and at least one heat exchanger.

[0018] The invention can finally be extended to an electric or hybrid motorized vehicle comprising a rotor assembly, a ventilation unit and / or an electric machine according to the invention.

[0019] Other details, features and advantages will become clearer upon reading the detailed description given below, by way of example and not limitation, in relation to the various embodiments illustrated in the following figures:

[0020] Fig. 1 is a schematic representation of an embodiment of a vehicle equipped with an electric machine according to the invention.

[0021] Fig. 2 is a schematic cross-sectional representation of an example embodiment of an electrical machine comprising an example embodiment of a rotor assembly.

[0022] Fig. 3 is a schematic representation of the rotor assembly including a fluid ventilation element.

[0023] Fig. 4 is a schematic perspective representation of an example of a first embodiment of the ventilation device.

[0024] Fig. 5 is a schematic perspective representation of the ventilation unit illustrated in Fig. 4 fitted on a disc of the rotor assembly.

[0025] Fig. 6 is a schematic representation of a second embodiment of the ventilation unit according to the first embodiment fitted on the disc.

[0026] Fig. 7 is a schematic cross-sectional representation of an example of an embodiment of a fastening means relative to the ventilation organ.

[0027] Fig. 8 is a schematic cross-sectional representation of alternative ways of connecting the attached slats of the ventilation unit.

[0028] Fig. 9 is a schematic cross-sectional representation of a second embodiment of the ventilation organ.

[0029] The [Fig. 10] is a schematic cross-sectional representation of the second embodiment of the ventilation organ.

[0030] Fig. 11 is a schematic cross-sectional representation of a fastening means on which a cap is fitted.

[0031] Fig. 12 is a schematic cross-sectional representation of a third embodiment comprising a plurality of ventilation components.

[0032] Figure 1 schematically illustrates an example of an embodiment of a motor vehicle 1 according to the invention. Vehicle 1 is an electric or hybrid vehicle. Vehicle 1 can also be of any type, for example, a passenger car, a commercial vehicle, a truck, or a bus. In particular, the vehicle 1 in question can be a connected and / or autonomous vehicle.

[0033] The vehicle 1 is equipped with an axial flux electric machine 2 according to the invention and / or an arrangement 10 comprising said electric machine 2. It is understood, however, that the electric machine 2 may be implemented elsewhere than in a vehicle 1. The electric machine 2, also referred to as a traction and / or propulsion electric motor, comprises a housing 21 having a plurality of flanks delimiting an internal volume 20. For example, generally speaking, the housing 21 is cylindrical or substantially cylindrical with a circular base. Here, "housing" refers to a casing or structural enclosure, particularly a metallic one. Without limitation, the housing 21 comprises a first side 21a and a second side 21b, delimiting the housing 21 along a first direction 100. The housing 21 also comprises at least one intermediate side 21c, connecting the first side 21a to the second side 21b.

[0034] It is understood that throughout this description, the terms "first", "second", "primary", "secondary" are intended to distinguish similar elements and not to establish a hierarchy of importance.

[0035] The electric machine 2 comprises a stator 3 and a rotor assembly 4, configured to be movable relative to the stator 3. Generally, the rotor assembly 4 according to the invention comprises a disc 44 and a shaft 41 comprising at least one base 40 configured to carry said disc 44. Also, the rotor assembly 4 according to the invention comprises at least one ventilation element 5 for at least a first fluid Fl, in particular an airflow.

[0036] The stator 3 is disposed within the internal volume 20, at a non-zero distance from the rotor assembly 4. The space separating the stator 3 from the rotor assembly 4 is called the air gap. In this case, the internal volume 20 comprises a plurality of distinct air gaps, a first air gap 22a being disposed on one side of the disk 44 of the rotor assembly 4 and a second air gap 22b being disposed on a second side of the disk 44, opposite the first side. The disk 44 of the rotor assembly 4 is thus interposed between the first air gap 22a and the second air gap 22b. As is known, the stator 3 comprises an assembly of teeth and coils, not detailed, fixed within the internal volume 20. In this way, the rotor assembly 4 is able to be rotated relative to the stator 3.

[0037] The shaft 41 extends along an extension axis 400, here parallel to the first direction 100, and centered on said axis. The shaft 41 is configured to be free to rotate about an axis of rotation, here coinciding with the extension axis 400. In particular, it has a cylindrical structure, for example, at least partially circular in base. The shaft 41 extends through at least a portion of the housing 21 along the first direction 100. In particular, the shaft 41 is made of a metallic material such as steel.

[0038] The term "axial flux electric machine" means that the direction of the generated magnetic flux is aligned parallel to the axis of rotation or the axis of extension 400 of the shaft 4L. The shaft 41 extends, for example, transversely, or even perpendicularly, to the first flank 21a and / or the second flank 21b of the housing 21.

[0039] Optionally, as is known, the shaft 41 is hollow and includes a bore 42 suitable for allowing the circulation of the first fluid Fl, as further detailed below. The bore 42 opens at at least one first end 41a of the shaft 41, that is to say, it opens towards the environment external to the electrical machine 2 at a supply port 43 for the first fluid Fl, allowing said fluid to enter the bore 42.The bore 42 extends over at least a portion of a length of the shaft 41, measured along the first direction 100 between the first end 41a and a second, opposite end 41b of the shaft 4L. The shaft 41 further comprises a plurality of cannulas 45, corresponding in particular to bores made in the material of the shaft 41, and extending between the bore 42 and an external periphery 410 of the shaft 4L. The cannulas 45 permit the circulation of at least a portion of the first fluid Fl from the bore 42 to the internal volume 20 so as to circulate in contact with at least the rotor assembly 4.The cannulas 45 advantageously ensure the natural movement of the first fluid Fl in the electric machine 2, i.e., without requiring the integration of a pump dedicated to projecting the first fluid Fl towards the internal volume 20 in the vehicle 1, since the rotation of the shaft 41 creates a pumping effect, i.e., the first fluid Fl is drawn, via the bore 42 and the aforementioned channels, towards the internal volume 20 due to centrifugal force. In particular, the cannulas 45 are regularly arranged along the circumference of the shaft 4L. For example, the inlets and / or outlets of said cannulas are arranged so that they are traversed by the same plane orthogonal to the extension axis 400 of the shaft 4L. Alternatively, the cannulas are distributed in a plurality of sub-assemblies arranged along the length of the shaft 4L.

[0040] Alternatively or additionally, the housing 21 includes at least one inlet of the first fluid Fl into the internal volume 20 and at least one outlet of said fluid, not shown, respectively ensuring the supply and discharge of the first fluid Fl into the internal volume 20 so as to circulate in contact with the rotor assembly 4. For example, said inlet and outlet are arranged in one of the flanks, in particular the first flank 21a or the second flank 21b of the housing 21.

[0041] The disk 44 carried by the shaft 41 is intended to rotate concurrently with the shaft 4L. Conventionally, the disk 44 comprises a star 44a, in particular made of composite material, connected to the shaft 41 and carrying a plurality of magnets 44b. The various magnets 44b are arranged in blocks so as to fit within the shape of a disk 44, or substantially a disk 44.

[0042] The disc 44 comprises a first face 440 and a second face 441, opposite each other. The disc 44 further comprises a central cutout adapted to receive the shaft 41, and a plurality of primary holes 47 suitable for receiving fastening means 6, such as screws or screw-nut assemblies.

[0043] The base 40 of the shaft 41 extends transversely, or even orthogonally to the extension axis 400. The base 40 is configured to support at least part of the disk 44, in particular the star 44a of the disk 44. To this end, in order to ensure suitable mechanical resistance, the base 40 is optionally but preferably made of a metallic material, such as steel.

[0044] The shaft 41, particularly the base 40, includes a plurality of secondary holes 48 suitable for receiving the means for fixing the disc 44 on the shaft 4L. When the disc 44 is mounted on the shaft 41, at least a portion of the primary holes 47 extends opposite the secondary holes 48 so that a particular fixing means 6 is suitable for extending through one of the primary holes 47 and one of the secondary holes 48.

[0045] Generally, at least one ventilation element 5 is at least partly connected to the disc 44 and / or the shaft 4L. At least one ventilation element 5 comprises a base 51 and a plurality of slats 52 optionally connected to the base 51, which can also be described as fins.

[0046] The base 51 is arranged so as to at least partially surround the shaft 41, in particular the portion of the shaft 41 comprising the bore 42. The slats 52 extend transversely, for example perpendicularly to the base 51, projecting from the latter. The slats 52 are arranged around the shaft 41, that is to say, arranged in a circular, substantially circular, annular, or substantially annular shape, or alternatively, arranged so as to be traversed by such a circular shape. For example, such a circular or annular shape is centered on the extension axis 400. Optionally, the lamellae 52 are arranged in contact with or near the outer periphery 410 of the shaft 4L. By "lamellae" we mean fins formed by walls or ribs whose thickness is strictly less than a length and / or height of a lamella considered.At least one ventilation element 5 comprises a plastic material, in particular filled, and / or a metallic material, and / or a composite material. Optionally, the "blades" 52 or fins may also be wholly or partly extended over a portion of the disc 44.

[0047] Figures 2 to 12 illustrate different examples of embodiment of at least one ventilation element 5. The description below is made with reference to a rotor assembly 4 comprising a ventilation element 5, it is nevertheless understood that it extends to a ventilation element 5 comprising a plurality of ventilation elements, as described below with reference to [Fig. 12].

[0048] Preferably, the slats 52 are regularly arranged within the ventilation element 5. In other words, the slats 52 are regularly arranged around the shaft 41 and / or the extension shaft 400 of the shaft 41. Alternatively or additionally, the vanes 52 are regularly arranged relative to at least one of the plurality of primary holes 47 and the plurality of secondary holes 48 when the rotor assembly 4 is assembled. "Regularly arranged" means that the vanes 52 are separated from adjacent vanes 52 by equal or substantially equal spacings 53. This principle ensures homogeneous movement, or ventilation, of the first fluid Fl when the rotor assembly 4 is rotated, the vanes 52 then acting as blades or vanes in contact with said fluid.

[0049] For example, the lamellae 52 are distributed around the shaft 41 such that the proximal ends of said lamellae 52, those closest to the shaft 41, are traversed by radial axes originating from the extension axis 400 and regularly spaced. Additionally or alternatively, depending on the shape and arrangement of the lamellae 52, the lamellae 52 are distributed around the shaft 41 such that the distal ends of said lamellae 52, those furthest from the shaft 41 and opposite the proximal ends, are traversed by radial axes originating from the extension axis 400 and regularly spaced, said axes being either common to or distinct from the radial axes passing through the proximal ends.

[0050] As illustrated in [Fig. 4] or, optionally, in Figure 5, at least some of the lamellae 52 of the plurality of lamellae 52 are curved, i.e., in the shape of an arc. In particular, the curvature of the different lamellae 52 of the plurality of lamellae 52 is similar or substantially similar. According to an alternative or additional embodiment, at least some of the lamellae 52 of the plurality of lamellae 52 are at least partly straight. Preferably, all the lamellae 52 of the plurality of lamellae 52 are curved, or all the lamellae 52 of the plurality of lamellae 52 are at least partly straight, such that the different lamellae 52 have a similar or substantially similar profile, here evaluated in a plane orthogonal to the extension axis 400 of the shaft 41.

[0051] Optionally, all or part of the slats 52 of the plurality of slats may have a similar or substantially similar shape and / or dimensions. This principle makes it possible to homogenize the ventilation of the first fluid Fl while reducing the number of references required to implement the invention.

[0052] Optionally, all or part of the slats 52 includes a complementary cutout 54 shaped to match at least one counterform included in the housing 21, for example one of the sides, or in the shaft 41. For example, such a complementary cutout 54 is disposed at the proximal end of the slat in question for shape complementarity with the shaft 41 or at the distal end for shape complementarity with the housing 21, such as visible in [Fig.6] or 10. Optionally, an additional part and / or additional parts including the counterform, attached or not, in particular in fixed opposites, may be arranged at the level of the casing 21, for example on one of the sides, or in the shaft 41 in order to adapt and reduce the existing clearances relative to said slats 52 in order to improve the "pumping" capacity and in order to reduce any pressure losses.

[0053] Figures 2 to 7 illustrate an example of an embodiment of a first embodiment of the ventilation member 5 in which the base 51 of the ventilation member 5 is attached and fixed to the disc 44 or to the base 40 of the shaft 41. The base 51 of the ventilation member 5 can then be positioned on one of the first face 440 or the second face 441 of the disc 44, for example at the level of the star 44a. In particular, the base 51 of the ventilation element 5 is disposed on one of the first face 440 or the second face 441 while the base 40 of the shaft 41 is disposed in contact with the other of the first face 440 or the second face 441 of the disc 44. In this case, the base 51 of the ventilation element 5 is disposed in contact with the first face 440 of the disc 44.According to an alternative not shown, such a principle applies mutatis mutandis for a position of the base 51 on the base 40 of the shaft 41 relative to a first surface 40a and a second surface 40b of said base 40.

[0054] In such an embodiment, the base 51 comprises a plurality of orifices 55 configured to receive the fastening means 6. Also, at least a part of said orifices 55 is configured to extend in relation to the primary holes 47 and / or the secondary holes 48.

[0055] According to a particular, optional embodiment, at least part of the slats 52 of the plurality of slats 52 are attached and fixed to the base 51 of at least one ventilation element 5. For example, said slats 52 are connected to the base 51 by means of a sliding connection, a clip connection, by welding or by gluing.

[0056] In the case of a sliding connection, the base 51 comprises, for the slats 52 considered, a rail 56 formed by a groove, a pair of ribs, or a pair of complementary walls shaped like the slats 52. The insertion of a slat into the rail 56 considered is then achieved by sliding and / or translation according to the shape of the rail 56 considered, that is, whether it is curved or straight. Optionally, as schematically illustrated in [Fig. 8], the rail 56 may have a simple profile, square or rectangular for example. Alternatively, the rail 56 and the slat considered may have complementary profiles comprising an "L" or "T" shape, the slat considered then comprising at least one lower edge 57 configured to abut a portion of the rail 56 along a direction transverse, or even orthogonal, to the direction of insertion of said slat 52 into the rail 56.

[0057] In the case of a clip-on connection, not shown, the base 51 comprises, for example, elastically deformable teeth or ribs configured to engage with the lamella 52 in question, on either side thereof. Optionally, the lamella 52 comprises at least one lower edge 57 configured to abut against a portion of one of the teeth or ribs as indicated above.

[0058] Optionally, additionally, or alternatively, the rotor assembly 4 includes the fastening means 6 as indicated above, each fastening means 6 comprising a head 61. In particular, and preferably, the heads 61 of the fastening means 6 are spherical or milled so as to limit turbulence and pressure losses of the first fluid Fl circulating in the internal volume 20, as shown in [Fig. 7]. Optionally, at least some of the slats 52 of the plurality of slats 52 may be connected to the fastening means 6 in a removable or non-removable manner, as shown in one of the examples in [Fig. 8]. The fastening means 6 and at least one slat 52, disposed at the head 61, form, for example, a single unit, i.e., they are made of a single piece of material and cannot be separated or dissociated without resulting in their degradation.The fastening means 6 is then reported relative to the base 51 of the ventilation member 5 so that the slat 52 is indirectly connected to the base 51. Alternatively, at least one slat 52 is reported and fixed to the head 61 of one of the fastening means 6, either by bonding, by welding or by means of a sliding connection in a rail 56 as described above and illustrated in [Fig.8], the head 61 then comprising the groove or a pair of ribs.

[0059] According to yet another alternative, illustrated in [Fig. 11], the rotor assembly 4 further comprises at least one cap 58 attached to and disposed at the head 61 of at least one of the fastening means 6. The blade 52 is then connected to said cap 58 instead of the head 61, and the above description, relating to the one-piece or attached connection of the blade 52 to the head 61, applies here mutatis mutandis. Such a cap 58 can, in particular, be used to cover hexagonal heads 61 in order to reduce turbulence and pressure losses of the first fluid FL. In particular, said cap 58 is at least partially spherical or milled and includes a complementary housing shaped like the head 61 of the fastening means 6, suitable for receiving the latter.

[0060] The integration of added blades 52 advantageously allows for greater modularity of the ventilation element 5, so that it is possible to select blades 52 of shape and / or dimensions adapted to the model and architecture of a wide variety of electrical machines. The blades 52 and the base 51 can then be made of similar materials or of different materials from those mentioned above.

[0061] According to an alternative illustrated in [Fig.4], the base 51 and at least part of the slats 52 of the plurality of slats 52 form a single unit attached relative to the disk 44 or the shaft 41, in particular to the base 40. The base 51 and said slats 52 are then made of similar or different materials, the base 51 being, for example, overmolded onto said slats 52.

[0062] Preferably, in such an alternative, all the slats 52 and the base 51 form a single unit, or all the slats 52 are attached relative to the base 51. It is understood, however, that the ventilation element 5 may comprise a combination of one or more of the aforementioned alternatives. The ventilation element 5 may thus comprise different subsets of slats 52, a first subset of slats 52 and the base 51 forming a single unit, while a second subset of slats 52 is attached relative to the base 51. Alternatively, the ventilation element 5 may comprise different subsets of attached slats 52 implementing different alternatives described above.

[0063] Optionally and independently of the connection implemented between the slats 52 and the base 51, the base 51 of at least one ventilation element 5 comprises a plurality of washers 59, comprising a plastic material, for example filled, or a metallic material such as steel, distinct from the rest of the base 51. The ventilation element 5 is thus, for example, obtained by overmolding the base 51 onto the washers 59. Said washers 59 have a receiving function for the fastening means 6; they delimit and / or surround the orifices 55 of the base 51 so as to receive the fastening means 6. They also have a supporting function, in particular for the heads 61 of the fastening means 6, and provide strength.

[0064] Figures 9 and 10 illustrate an example of a second embodiment in which the base 51 of the at least ventilation element 5 forms a single unit with the disc 44 or with the base 40 of the shaft 4L. In other words, one of the faces of the disc 44, in particular the first face 440 of the disc 44, coincides with the base 51 or, alternatively, one of the surfaces of the disc 44, in particular the second surface 40b which is opposite the disc 44, coincides with the base 51. By extension, the orifices 55 of the base 51 as described above are here coincident with the primary orifices 55 of the disc 44 or the secondary orifices 55 of the base 40 of the shaft 41 depending on the element comprising the base 51.

[0065] The preceding description, relating to the first embodiment, applies here mutatis mutandis. Also, optionally but preferably, all or part of the slats 52 of the ventilation element 5 according to the second embodiment can be attached to the base 51, i.e., here on the disc 44 or the base 40 of the shaft 41. The various alternative attachments of the attached slats 52 described previously also apply to this embodiment. Similarly to what has been described above, optionally, at least one slat 52 is disposed on one of the fastening means 6 or on a cap 58 attached to one of the fastening means 6. Alternatively, all or part of the slats 52 of the ventilation element 5 and the base 51, i.e., here the disc 44 or the base 40 of the shaft 41, form a single unit. Optionally, the base 51 formed by the base 40 of the shaft 41 or the disc 44 may include the washers 59.It is understood that the various alternatives described, relating to a ventilation element 5 partially made of material, entirely made of material, of which at least some of the slats 52 are added or of which all of the slats 52 are added, extend to the present embodiment.

[0066] According to a third embodiment, schematically illustrated in [Fig. 12], the rotor assembly 4 comprises a plurality of ventilation elements 5 for the first fluid Fl. At least one ventilation element 5, hereinafter referred to as the first ventilation element 5a, is then connected to one of the shaft 41 or the disc 44 and a second ventilation element 5b is connected to the other of the shaft 41 or the disc 44. In other words, the first ventilation element 5a is disposed in one of the first air gap 22a or the second air gap 22b and the second ventilation element 5b is disposed in the other of the first air gap 22a or the second air gap 22b so that said ventilation elements are disposed at opposite sides of the disc 44.

[0067] It is understood that the first ventilation element 5a and the second ventilation element 5b can be implemented according to the various alternative embodiments described above, in particular with reference to the first and second embodiments. Different embodiments can thus be implemented for separate ventilation elements 5 or, alternatively, the different ventilation elements 5 can be implemented according to the same embodiment.

[0068] For example, according to the non-limiting embodiment illustrated in [Fig. 12], the first ventilation element 5a is made according to the first embodiment and comprises a base 51 attached and fixed to the disc 44, in particular to the first face 440 of the disc 44. The second face 441 of the disc 44 is disposed in contact with the first surface 40a of the base 40. The second ventilation element 5b is made according to the second embodiment and disposed at the level of the second surface 40b of the base 40 of the shaft 41, the base 51 of said ventilation element 5 and the second surface 40b of the base 40 being coincident.

[0069] Regardless of the embodiment implemented, at least a portion of the slats 52 is arranged at the spacings 53 separating the orifices 55, The primary holes 47 and / or adjacent secondary holes 48 are suitable for receiving the fastening means 6. Alternatively or additionally, at least a portion of the slats 52 is positioned at the orifices 55, the primary holes 47, and / or the secondary holes 48 when said slats 52 are positioned on the fastening means 6 or on a cap 58 positioned on one of the fastening means 6, as described above. Regardless of the alternative implemented, optionally but preferably, the slats 52 are regularly arranged and spaced from one another, as indicated above.

[0070] Optionally, at least part of the slats 52 is arranged opposite an outlet of at least one of the cannulas 45 of the shaft 41. Such a principle makes it possible to separate a flow of the first fluid Fl circulating in said cannula 45 into two when it exits the shaft 41 to be distributed in the internal volume 20 of the electric machine 2, which allows an optimization of the distribution and circulation of the first fluid Fl and, consequently, an optimization of the thermal management of the rotor assembly 4.

[0071] In a known manner, the axial flow electric machine 2 is optionally configured to allow the circulation of the first fluid Fl and a second fluid F2, separate from the first fluid Fl. In the vehicle 1 and the arrangement 10 comprising the electric machine 2, the first fluid Fl and the second fluid F2 circulate respectively through a first circuit Cl and a second circuit C2, separate from each other. The first fluid Fl and the second fluid F2 are thus not in direct contact with each other or mixed. According to a preferred embodiment, the second fluid F2 is an oil.

[0072] The first circuit Cl includes, for example, a first heat exchanger HX1, notably intended for managing at least one component of the vehicle 1, such as an electric battery and / or a power electronics component. The first circuit Cl includes, in particular, at least one recirculation or redirection line for a portion of an airflow passing through the first heat exchanger HX1, intended to form the first fluid FL. The first circuit Cl may optionally be without a pump for moving the first fluid Fl, the cannulas 45 of the shaft 41 being suitable for drawing the first fluid Fl into the internal volume 20 of the electric machine 2 as described above.

[0073] The vehicle 1 thus optionally comprises an arrangement 10 including the rotor assembly 4 and / or the electric machine 2 described above, as well as at least one heat exchanger, in particular at least the first HX1 heat exchanger. Optionally, such an arrangement 10 further comprises the first circuit Cl, this extending at least between at least one heat exchanger, here the first heat exchanger HX1, and the rotor assembly 4.

[0074] Similarly, the second circuit C2 optionally includes a second heat exchanger HX2, located at the front of the vehicle 1 and capable of facilitating heat exchange between the second fluid F2, for example, a coolant, and an outside airflow or a separate cooling fluid, such as water or glycol water. Optionally, the arrangement 10 includes the second circuit C2, configured to allow the circulation of the second fluid F2, and the second heat exchanger HX2.

[0075] To allow the separation of the first and second circuits C1, C2, the electrical machine 2 includes, in particular, at least one sealing membrane 8 arranged to delimit at least one primary compartment 24 and at least one secondary compartment 25. As is known, the sealing membrane 8 can be fixed to the housing 21 and / or the stator 3, for example by means of an adhesive, in order to limit the space generated within the internal volume 20. It should be noted that the electrical machine 2 may include a plurality of sealing membranes. The sealing membrane 8 is arranged to separate the rotor assembly 4 from all or part of the stator assembly 3. In this case, a first membrane 8 extends at the level of the first air gap 22a and a second membrane 8 extends at the level of the second air gap 22b.

[0076] The primary compartment 24 is arranged within the internal volume 20 so as to include all or part of the stator 3 and is adapted to allow the circulation of the second fluid F2 in order to provide thermal management for said stator 3, particularly its cooling. The housing 21 includes the inlet and outlet of the second fluid F2, not shown, which respectively supply and discharge said fluid into the primary compartment 24.

[0077] The secondary compartment 25 delimits, for its part, a compartment in which the rotor assembly 4 extends, in particular at least part of the shaft 41 and the disc 44. The first fluid Fl thus makes it possible to ensure the thermal management, in particular the cooling, of the rotor assembly 4, in particular of the various magnets 44b, in parallel with the thermal management of the stator 3.

[0078] Thus, when the electric machine 2 is in operation, particularly within the vehicle 1, the first fluid Fl circulates in the first circuit CL. For example, the first fluid Fl is cooled at the first heat exchanger HX1, then sent to the internal volume 20 of the electric machine 2. The first fluid Fl enters the shaft 41 through the feed port 43 and passes through the bore 42. The first fluid Fl is sent to the various nozzles 45 to be distributed in the internal volume 20. When the rotation of The shaft 41 of the rotor assembly 4 generates a pressure difference between a zone radially close to the shaft 41 and a zone radially further away from the extension axis 400. Centrifugal force then draws the first fluid Fl towards the various air gaps, towards the sides of the housing 21, specifically towards at least one intermediate side 21c, thus moving it away from the shaft 41. At least one ventilation element 5 advantageously optimizes the pumping and ventilation capacity of the rotor assembly 4. The movement of said ventilation element 5, along with the disc 44 and the shaft 41, increases the movement of the first fluid Fl within the internal volume 20 through contact of the vanes 52 with said fluid. These vanes 52 then function similarly to blades or blades.Indeed, the vanes 52 allow the centrifugal force of the first fluid Fl towards the air gaps 22a, 22b, that is to say, an acceleration of the first fluid Fl by creating a pressure differential, in other words, a delta P between the upstream and downstream sides of the vanes 52, depending on the direction of flow of the first fluid Fl. Optionally, such a principle eliminates the need to integrate a pump to set the first fluid Fl in motion. The first fluid Fl, thus passing into contact with the magnets 44b of the rotor assembly 4, absorbs at least some of their heat and allows them to be cooled.Alternatively or additionally, the axial flux electric machine 2 according to the invention and / or the arrangement 10 is configured so that the rotor assembly 4 is open to the external environment and in fluidic connection with the external environment so as to allow the entry of the first fluid Fl, in particular at the shaft 41 as described above, at a lower temperature.

[0079] Additionally, when the electrical machine 2 includes at least one membrane 8, as described above, the first fluid Fl circulates in contact with it and advantageously absorbs some of its heat, allowing it to cool down. The first heated fluid Fl can then be discharged from the casing 21, for example via a discharge channel, not shown, included in one of the sides of the casing 21. The first fluid Fl is then directed to the environment external to the electrical machine 2.

[0080] When the second fluid F2 also circulates in the electrical machine 2, as described above, the second fluid F2 is brought into the internal volume 20, specifically into the primary compartment 24, through at least one inlet, not shown, located in one of the sides of the casing 21. The second fluid F2 circulates in the primary compartment 24 and absorbs heat from the stator 3, thus cooling it. The second fluid F2 is then discharged through the outlet of said fluid. The second fluid F2 can then, for example, be returned to the second heat exchanger HX2, where it releases heat to the fluid cooling, allowing its cooling before it is returned to the internal volume 20 of the casing 21.

[0081] The invention thus proposes a rotor assembly and an electric machine for distributing a fluid, in particular an airflow, within an internal volume of the electric machine, optimizing the pumping and ventilation capacity of said fluid in order to improve the thermal management of said rotor in a simple and economical manner. The invention also optionally eliminates the need to integrate a pump to move the fluid into the internal volume of the electric machine.

[0082] The present invention cannot, however, be limited to the means and configurations described and illustrated herein and it also extends to any equivalent means or configuration and to any technically operative combination of such means insofar as they ultimately fulfill the functionalities described and illustrated in this document.

Claims

Demands

1. Rotor assembly (4) for an axial flux electric machine (2), in particular for a motor vehicle (1), comprising a disc (44), at least one ventilation element (5) for at least one fluid and a shaft (41) comprising a base (40) configured to carry the disc (44): - the disc (44) and the shaft (41) comprising respectively a plurality of primary holes (47) and a plurality of secondary holes (48) suitable for receiving means for fixing (6) the disc (44) to the shaft (41); - at least one ventilation element (5) being at least partly connected to the disc (44) and / or the shaft (41) and at least one ventilation element (5) comprising a base (51) and a plurality of blades (52), in particular at least partly connected to the base (51), arranged around the shaft (41) and extending transversely and projecting from the base (51).

2. Rotor assembly (4) according to the preceding claim, wherein the blades (52) are regularly arranged around the shaft (41) and / or relative to at least one of the plurality of primary holes (47) and the plurality of secondary holes (48).

3. Rotor assembly (4) according to any one of the preceding claims, wherein: - the base (51) of at least one ventilation element (5) is attached and fixed to the disc (44) or to the base (40) of the shaft (41); or - the base (51) of at least one ventilation element (5) forms a single unit with the disc (44) or with the base (40) of the shaft (41).

4. Rotor assembly (4) according to any one of the preceding claims, wherein: - the base (51) of at least one ventilation element (5) comprises a plurality of washers (59), comprising a plastic or metallic material, suitable for receiving the fastening means (6); and / or - at least a portion of the blades (52) of the plurality of blades (52) are attached and fixed to the base (51) of at least one ventilation element (5).

5. Rotor assembly (4) according to any one of the preceding claims, wherein: - at least part of the lamellae (52) of the plurality of lamellae (52) are curved; and / or - at least part of the lamellae (52) of the plurality of lamellae (52) are at least partly straight.

6. Rotor assembly (4) according to any one of the preceding claims, wherein at least one ventilation element (5) comprises a plastic material, in particular filled, and / or a metallic material and / or a composite material.

7. Rotor assembly (4) according to any one of the preceding claims, comprising a plurality of ventilation elements (5) of at least one fluid, at least one ventilation element (5), hereinafter referred to as the first ventilation element (5a), being connected to one of the shaft (41) or the disc (44) and a second ventilation element (5b) being connected to the other of the shaft (41) or the disc (44).

8. Rotor assembly (4) according to any one of the preceding claims, further comprising a plurality of means for fixing (6) the disc (44) to the shaft (41) each comprising a head (61): - at least a portion of the slats (52) of the plurality of slats (52) being connected to the fixing means (6); and / or - the rotor assembly (4) further comprising at least one cap (58) attached and disposed at the head (61) of at least one of the fixing means (6) at least one of the slats (52) being connected to the at least one cap (58).

9. Ventilation element (5) for a rotor assembly (4) according to any one of the preceding claims, comprising a base (51) and a plurality of vanes (52) directly or indirectly connected to the base (51).

10. An axial flux electric machine (2), in particular for a motor vehicle (1), comprising: - a stator (3), having a housing (21) delimiting an internal volume (20); and - a rotor assembly (4) according to any one of claims 1 to 8 and / or a ventilation element (5) according to the preceding claim.

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