Rotor assembly for an axial flux electric machine, particularly for motor vehicles, and axial flux electric machine comprising it

Abstract

Title: Rotor assembly for an axial flux electric machine, particularly for motor vehicles, and axial flux electric machine comprising it. Rotor assembly (4) for an axial flux electric machine (2) comprising a shaft (41) and a disk (44), the shaft (41) comprising a bore (42) configured to allow the circulation of a first fluid (F1), a spacer (6) and a base (9) carrying the disk (44) comprising and / or delimiting a distribution circuit (7) for the first fluid (F1) in an internal volume (20) of the electric machine (2). Abstract figure: Figure 3

Description

Title of the invention: Rotor assembly for an axial flux electric machine, particularly for motor vehicles, and 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. The invention also relates to an axial flux electric machine comprising such a rotor assembly. The invention further relates to an arrangement and 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 with a shaft rotating near a stator. Because the rotor 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. into the space between the stator and the rotor.

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

[0005] Conventionally, it is known to integrate into the electric machine an airflow circuit that passes at least partially through the rotor, propelled within the electric machine by means of a circuit including, in particular, an air pump. However, such a solution has the disadvantage of being very bulky and not allowing for homogeneous cooling of the rotor.

[0006] The present invention falls within this context and aims to provide an alternative to known axial flux electric machines for ensuring rotor thermal management in order to optimize cooling homogeneity. The invention also aims to limit the size required to achieve such thermal management.

[0007] The invention relates to a rotor assembly for an axial flux electric machine, in particular for a motor vehicle, comprising a disc and a shaft extending along an extension axis on which it is centered, the shaft comprising a bore, configured to allow the circulation of a first fluid, and a plurality of distribution channels for said fluid, connecting the bore to an external periphery of the shaft.

[0008] The rotor assembly further comprises: - a first fluid distribution circuit arranged around the shaft in fluidic connection with the distribution channels, and comprising a plurality of primary and secondary cannulas configured to allow the circulation of the first fluid respectively to a first space of the electrical machine, arranged on a first side of the rotor disk and to a second space, arranged on a second side of the disk, opposite to the first side; - a spacer at least partly disposed between the disc and the outer periphery comprising and / or delimiting at least partly the distribution circuit of the first fluid;

[0009] - a base, connected to the shaft and extending transversely to the axis of extension, carrying the disc and including and / or delimiting at least in part the distribution circuit.

[0010] In particular, the spacer is an added part made of metallic material, mounted and fixed on the shaft by shrink fitting and / or welding.

[0011] In particular, the distribution circuit comprises a plurality of bifurcation points, at least one pair comprising one of the primary cannulas and one of the secondary cannulas being connected to each of said bifurcation points: - the base including the bifurcation points; or -1'spacer delimiting the bifurcation points.

[0012] According to embodiment examples, the plurality of primary cannulas: - is at least partially contained within the spacer and / or delimited by the spacer; or - is at least partly contained within the disk.

[0013] According to embodiment examples, the plurality of secondary cannulas: - is at least partially contained within the spacer and / or delimited by the spacer; and / or - is at least partly included in the base.

[0014] According to alternative embodiments: - the spacer and the base form a single unit, notably made of a metallic material; or - the base and the shaft form a single unit, notably made of a metallic material.

[0015] Optionally: - Secondary cannulas are defined by at least one secondary diameter and primary cannulas are defined by at least one primary diameter, the at least one secondary diameter being equal to the at least one primary diameter; and / or - the plurality of secondary cannulas includes a number of secondary cannulas equal to a number of primary cannulas in the plurality of primary cannulas.

[0016] In particular: - the outlets of the primary cannulas, opening into the first space, are separated from the axis of extension by a primary distance, defined along a radial direction from said axis, equal to, or substantially equal to; - the outlets of the secondary cannulas, opening into the second space, are separated from the axis of extension by a secondary distance, defined along a radial direction from said axis, equal to, or substantially equal to; - the primary distance and the secondary distance being equal or approximately equal.

[0017] The invention also relates to an axial flux electric machine, in particular for a motor vehicle, comprising a stator, a housing delimiting an internal volume and a rotor assembly according to the invention, the shaft extending through the internal volume so that the primary cannulas and secondary cannulas open into said internal volume.

[0018] The invention also extends to an arrangement, in particular for a motor vehicle, comprising an electrical machine according to the invention and at least one heat exchanger.

[0019] The invention finally relates to an electric or hybrid motorized vehicle comprising a rotor assembly and / or an electric machine according to the invention.

[0020] 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:

[0021] Fig. 1 is a schematic representation of an embodiment of a vehicle equipped with an electric machine according to the invention.

[0022] Fig. 2 is a schematic cross-sectional representation of an example of an embodiment of a first embodiment of an electrical machine comprising an example of an embodiment of a rotor assembly.

[0023] Fig. 3 is a schematic cross-sectional representation of the rotor assembly.

[0024] Fig. 4 is a schematic representation of part of a shaft of the rotor assembly.

[0025] Fig. 5 is a schematic cross-sectional representation viewed from above of the tree.

[0026] Figure 6 is a schematic cross-sectional representation of an example embodiment of a second embodiment of the electrical machine.

[0027] 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 utility vehicle, a truck, or a bus. In particular, the vehicle 1 in question can be a connected and / or autonomous vehicle.

[0028] The vehicle 1 is equipped with an axial flux electric machine 2 according to the invention and / or an arrangement comprising said electric machine 2. It is understood, however, that the electric machine 2 may be implemented in a location other than 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 sides delimiting an internal volume 20. For example, generally, the housing 21 is cylindrical or substantially cylindrical with a circular base. Here, "housing" means 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.

[0029] 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.

[0030] The electric machine 2 comprises a stator 3 and a rotor assembly 4, configured to be movable relative to the stator 3. As is known, the rotor assembly 4 comprises a shaft 41 extending along an extension axis 400, here parallel to the first direction 100, and centered on said axis. The shaft 41 is configured to be movable in rotation about an axis of rotation, here coinciding with the extension axis 400. In particular, it has a structure that is at least partially cylindrical, for example, with a circular 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. Preferably, the shaft 41 is a single piece, that is to say, made from a single piece of material.

[0031] 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. In particular, the shaft 41 is hollow and includes a bore 42. The shaft 41 is thus suitable for allowing the circulation of a first fluid Fl, in particular an airflow, as 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 allowing the entry of said fluid into 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

[0032] . The rotor assembly 4 also includes a disk 44 carried by the shaft 41 and intended to rotate concomitantly with the shaft 4L. Conventionally, the disk 44 includes a star 44a, in particular made of composite material, connected to the shaft 41, in particular to an outer periphery 410 of the shaft 41, and carrying a plurality of magnets 44b. The various magnets 44b are in particular arranged in blocks so as to fit within the shape of the disk 44, or substantially a disk.

[0033] 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 rotated relative to the stator 3.

[0034] In general, the rotor assembly 4 according to the invention further comprises a plurality of distribution channels 5 for the first fluid Fl, connecting the bore 42 to the outer periphery 410 of the shaft 41, a spacer 6 at least partially disposed between the disc 44 and the outer periphery 410 of the shaft 41, a distribution circuit 7 for the first fluid Fl comprising at least a plurality of primary cannulas 71 and secondary cannulas 72, and a base 9 connected to the shaft and at least partially supporting the disc 44. In particular, the base 9 comprises orifices 95 adapted to receive means for fixing the disc 44 10, configured to maintain the disc 44 attached to said base 9.

[0035] The distribution channels 5 correspond in particular to bores made in the material of the shaft 4L. The distribution channels 5 ensure the natural movement of the first fluid Fl in the electric machine 2, that is to say, without requiring the integration of a pump dedicated to projecting the first fluid Fl towards the internal volume 20 in the vehicle 1 or the arrangement. The rotation of the shaft 41 causes a pumping effect, that is to say a suction of the first fluid Fl through the bore 42 and said channels, towards the internal volume 20 due to the centrifugal force.

[0036] The distribution channels 5 extend between the bore 42 and the outer periphery 410 of the shaft 41. They are configured to open into the distribution circuit 7, as further detailed below. The distribution channels 5 thus form channels cut into the material of the shaft 41, opening into the bore 42 on one side and outside the shaft 41 on the other.

[0037] The distribution channels 5 are arranged so that different inlets of the first fluid Fl, specific to said channels, are arranged in an internal periphery 411 of the shaft 41, delimiting the bore 42. In particular, said inlets are arranged in a circular or substantially circular shape, crossed by at least one common plane, in particular a plane orthogonal to the extension axis 400 of the shaft 41, that is to say, so as to extend all to an equal or substantially equal distance from the supply port 43, said distance being evaluated along the first direction 100.

[0038] Outlets specific to the different distribution channels 5 are arranged in the outer periphery 410 of the shaft 4L. In particular, preferably, the outlets are arranged in a circular or substantially circular shape, crossed by at least one common plane, in particular a plane orthogonal to the extension axis 400 of the shaft 41, so as to extend all to the same distance from the supply port 43.

[0039] Optionally but preferably, the various distribution channels 5 are straight. Also, the distribution channels 5 are distributed around the circumference of the shaft 41, in particular in a regular manner, that is to say so as to have a regular spacing, in order to allow a homogeneous distribution of the first fluid Fl towards the environment outside the shaft, in particular towards the internal volume 20 and the distribution circuit 7, during the operation of the electrical machine 2.In particular, at least the outputs of the distribution channels 5 are regularly distributed within the outer periphery 410 of the shaft 4L. Optionally, but preferably, the inputs of the distribution channels 5 are regularly distributed within the inner periphery 411 of the shaft 41 and the outputs are regularly distributed within the outer periphery 410 of the shaft 41, said channels extending, for example, radially from the bore 42 towards the outer periphery 410 of the shaft 41, and converging towards the extension axis 400. Optionally, but preferably, the distribution channels 5 are arranged so as to extend orthogonally with respect to the extension axis 400.

[0040] The spacer 6 is an added part disposed on the shaft 41, particularly between the disc 44 and the outer periphery 410 of the shaft 4L. The spacer 6 is notably A metal part, for example made of steel, mounted and fixed to the shaft 41 by shrink fitting and / or welding. The spacer 6 has an annular shape, an inner face 61 of which is at least partially in contact with the outer periphery of the shaft 41. The spacer 6 includes and / or delimits at least partially the distribution circuit 7 of the first fluid FL. When the spacer 6 includes the distribution circuit 7, it comprises a plurality of channels cut into the material suitable for distributing the first fluid Fl from the distribution channels 5. When the spacer 6 delimits the distribution circuit 7, it comprises grooves forming at least part of a profile of one or more channels such that the distribution circuit 7 is at least partially delimited by the combination and cooperation of the shaft 41, in particular the outer periphery of the shaft 41, and the spacer 6.

[0041] The distribution circuit 7 is thus arranged in fluidic connection with the bore 42 and the distribution channels 5, the latter opening into the distribution circuit 7. In particular, the distribution circuit 7 extends at least partially opposite the distribution channels 5 of the shaft 4L. For example, as shown in [Fig. 2] or 3, grooves 62 formed in the inner face 61 of the spacer 6, extending parallel to the direction of extension of the shaft 41, are arranged opposite the distribution channels 5. The various grooves 62 are thus separated from adjacent grooves 62 by the material of the spacer 6 so as to optimize the contact between the spacer 6 and the shaft 4L. In particular, said grooves 62 are formed in angular sectors of equal dimensions, delimited by half-lines originating from the axis of extension of the shaft 41 and extending radially, as illustrated in [Fig.5].Conversely, preferably, the grooves 62 are arranged regularly within the spacer 6, that is to say that the spacing separating said grooves 62 is of equal dimension along the circumference of the spacer 6 or that angular sectors delimiting said spacings are equal or substantially equal.

[0042] According to an alternative not shown, the distribution circuit 7 comprises a groove common to all or part of the distribution channels 5, i.e. extending alongside all or part of said channels, said groove being inscribed in an annular shape surrounding the shaft 4L

[0043] It is understood that the alternative distribution circuit shapes 7 above apply mutatis mutandis to circuits comprising, additionally or alternatively, conduits cut into the spacer 6 instead of grooves 62.

[0044] The base 9 is connected to the shaft 41 so as to extend transversely, or even orthogonally, to the extension axis 400. The base 9 is configured to support at least part of the disk 44, in particular the star of the disk 44. To this end, in order to ensure suitable mechanical strength, the base 9 is preferably, made of a metallic material, such as steel. In particular, as illustrated in [Fig. 2] and as further explained below with reference to the various embodiments of the invention, the spacer 6 and the base 9 form a single unit, notably made of a metallic material. "Single unit" means that said elements are made of a single piece of material and cannot be separated from one another without resulting in the degradation, or even destruction, of said elements.

[0045] Alternatively, as shown in [Fig.6], the base 9 and the shaft 41 form a single unit, in particular made of a metallic material.

[0046] The primary cannulas 71 and the secondary cannulas 72 are conduits included in the distribution circuit 7, for example obtained by drilling or formed by grooves 62, to allow the circulation of the first fluid Fl in different spaces of the internal volume of the electrical machine 2. In particular, the primary cannulas 71 are configured to allow the distribution of a part of the flow of first fluid Fl to a first space 23a of the electrical machine 2, disposed on the first side of the rotor disc 44, here located at the level of the first air gap 22a, while the secondary cannulas 72 are configured to allow the distribution of another part of the flow of first fluid Fl to a second space of the electrical machine 2, disposed on the second side of the rotor disc 44, here located at the level of the second air gap 22b, i.e. opposite the first side.By extension, the first space 23a is arranged on one side of the base 9 and the second space 23b is arranged on a second side of the base 9, opposite the first side.

[0047] The primary cannulas 71 and the secondary cannulas 72 allow the separation of the first fluid Fl at the level of at least one bifurcation point 73, in particular at the level of a plurality of bifurcation points 73. In particular, at least one pair formed of a primary cannula 71 and a secondary cannula 72 is associated with each bifurcation point 73 considered, such a principle being able to be repeated all along the circumference of the shaft 41, the spacer 6 and / or the base 9.The bore 42, the distribution channels 5 and at least a part of the distribution circuit 7 arranged upstream of at least one bifurcation point 73 considered, according to a direction of circulation of said first fluid Fl, thus form a common path for the different portions of first fluid Fl then, at said bifurcation point 73, a portion of the first fluid Fl is directed towards one of the primary cannulas 71 while another portion of the first fluid Fl is directed towards one of the secondary cannulas 72. .

[0048] The various pairs of primary cannulas 71 and secondary cannulas 72 ensure the natural movement of the first fluid Fl in the electrical 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. The rotation of the shaft 41 causes a pumping effect, i.e., a suction of the first fluid Fl via bore 42, distribution circuit 7 and various cannulas to internal volume 20 due to centrifugal force.

[0049] Optionally but preferably, the bifurcation points 73 associated with the different pairs of primary cannulas 71 and secondary cannulas 72 are arranged in a circular or substantially circular shape, crossed by at least one common plane, in particular a plane orthogonal to the extension axis 400 of the shaft 41. In other words, said bifurcation points are arranged so as to extend to an equal or substantially equal distance from the first fluid supply orifice 43 Fl, said distance being evaluated along the first direction 100.

[0050] Similarly, optionally, primary outlets specific to the different primary cannulas 71 are arranged in a circular or substantially circular shape, crossed by at least one common plane, in particular a plane orthogonal to the extension axis 400 of the shaft 41, so as to all extend to the same distance from the first fluid supply orifice 43 Fl. The same applies to secondary outlets of the different secondary cannulas 72, these being preferably arranged in a circular or substantially circular shape, crossed by at least one common plane distinct from the plane specific to the primary cannulas 71, in particular a plane orthogonal to the extension axis 400 of the shaft 41, so as to all extend to the same distance from the first fluid supply orifice 43 Fl.

[0051] Figures 2 and 6 illustrate examples of implementation of different alternative embodiments of the invention.

[0052] According to a first embodiment, illustrated in Figures 2 to 5, the base 9 includes the bifurcation points 73 of the distribution circuit 7. Note that, in the illustrated example, the spacer 6 and the base 9 form a single unit. It is understood, however, that the present embodiment applies mutatis mutandis to a rotor assembly 4 in which the shaft 41 and the base 9 form a single unit.

[0053] The spacer 6 and / or the base 9 comprise the distribution circuit 7, and the bifurcation points 73 are located in the base 9. The secondary cannulas 72 thus extend through the base 9 so as to open into the second space 23a. The primary cannulas 71 extend through the disk 44, in particular through the star 44a. They are, for example, formed by perforations extending between opposite surfaces of the disk 44. Optionally, the primary cannulas 71 extend partially into the base 9. The primary cannulas 71 then optionally comprise different segments. Here, "segment" is understood to mean a portion of a whole. The primary cannula 71 and the secondary cannula 72 of a considered pair extend in particular at least partly opposite each other, on either side of a considered bifurcation point 73.

[0054] Optionally, the primary cannulas 71 and secondary cannulas 72 extend parallel or substantially parallel to the extension axis 400. Alternatively, the primary cannulas 71 and secondary cannulas 72 are inclined relative to an extension plane in which the disc 44 of the rotor assembly 4 extends, for example so as to extend towards a distal edge of the disc 44 furthest from the shaft 41.

[0055] The first fluid Fl thus flows through the bore 42 and then through the distribution channels 5, towards the distribution circuit 7. It should be noted that, in such an embodiment, the position of the distribution channels 5 shown is not limiting; they can be positioned closer to or further from the feed port of the shaft 41, while preferably remaining arranged in the same circular shape. The first fluid Fl then flows through the distribution circuit 7 contained within the spacer 7 and the base 9. When the flow of the first fluid Fl reaches one of the bifurcation points 73, it is divided so as to flow towards the first space 23a through the various primary cannulas 71 and towards the second space through the various secondary cannulas 72.

[0056] According to a second embodiment, illustrated in [Fig. 6], the bifurcation points 73 are included in the spacer 6. Note that, in the illustrated example, the shaft 41 and the base 9 form a single unit. It is nevertheless understood that the present embodiment applies mutatis mutandis to a rotor assembly 4 in which the spacer 6 and the base 9 form a single unit. In the present embodiment, the disc 44 advantageously lacks perforations for the circulation of the first fluid FL. The spacer 6 and / or the base 9 include the distribution circuit 7.

[0057] The secondary cannulas 72 extend at least partially into the base 9 so as to open into the second space 23b. Alternatively, the secondary cannulas 72 may be formed by grooves 62 in the spacer 6 and the outer periphery of the shaft 41, or by channels cut into the spacer 6, as described previously. The same applies to the primary cannulas 71.

[0058] The primary cannula 71 and the secondary cannula 72 of a given pair extend, in particular, at least partially opposite each other. Optionally, the primary cannulas 71 extend, at least partially, along the same direction, in particular at least partially orthogonally or substantially orthogonally to the extension axis 400. Such a principle, combined with regular spacing of the outlets of the primary cannulas 71, allows for a homogeneous distribution of the first fluid Fl in the first space 23a.

[0059] Optionally, the secondary cannulas 72 are inclined relative to the extension axis 400, for example so as to present an angle of inclination al, relative to the extension axis 400, strictly greater than an angle of at least part of the primary cannulas 71 relative to the extension axis 400. In this case, the secondary cannulas 72 are at least partially inclined so as to present an angle of inclination strictly greater than 90°, for example less than 160°, or even less than 145°. This principle facilitates the circulation of the first fluid Fl in the secondary cannulas 72, whose secondary outlets are further from the supply port 43 than the primary outlets of the primary cannulas 71.

[0060] The first fluid Fl thus flows through the bore 42 and then through the distribution channels 5 to the distribution circuit 7. It should be noted that, in such an embodiment, the distribution channels 5 and / or the bifurcation points 73 are preferably arranged so as to be located between the primary outlets of the primary cannulas 71 and the secondary outlets of the secondary cannulas 72 when moving along the extension axis 400. The first fluid Fl then flows through the distribution circuit 7 and is separated into several portions at the bifurcation points similarly to what has been described above.

[0061] In order to optimize the homogeneity of the flow of the first fluid Fl between the primary cannulas 71 on the one hand and the secondary cannulas 72 on the other hand, that is to say by extension in order to optimize the homogeneity of the flow of the first fluid Fl between the first space 23a and the second space 23b, different embodiment examples can be implemented.

[0062] According to an optional but preferred embodiment, the secondary cannulas 72 are defined by at least one secondary diameter, in particular equal or substantially equal within the plurality of secondary cannulas 72, and the primary cannulas 71 are defined by at least one primary diameter, in particular equal or substantially equal within the plurality of primary cannulas 71. Optionally, in order to optimize the homogeneity of the distribution of the first fluid Fl in the first space 23a and the second space 23b, the primary diameter and the secondary diameter are equal or substantially equal.

[0063] In particular, a width and / or depth of conduits of a part of the distribution circuit 7, in particular of grooves 62, arranged upstream of the primary cannulas 71 and of the secondary cannulas 72 according to the direction of flow of the first fluid Fl, is greater than or equal to the primary diameter and the secondary diameter.

[0064] Alternatively or additionally, the plurality of secondary cannulas 72 comprises a number kn2 of secondary cannulas 72 while the plurality of primary cannulas 71 comprises a number knl of primary cannulas 71. Optionally but preferably, the number knl of primary cannulas 71 is equal to the number kn2 of secondary cannulas 72.

[0065] Optionally, to further optimize the homogeneous thermal management of the rotor assembly 4 on both sides of the disc 44, the rotor assembly 4 is specifically configured so that the pumping effect enabling the aspiration of air towards the first space 23a and the second space 23b by centrifugal force is balanced on each side of the disc 44. To this end, the various primary outlets of the primary cannulas 71, opening into the first space 23a, are separated from the extension axis 400 by a primary distance Dk1, defined along a radial direction from said axis, equal to, or substantially equal to, this distance. Similarly, the various secondary outlets of the secondary cannulas 72, opening into the second space 23b, are separated from the extension axis 400 by a secondary distance Dk2, defined along a radial direction from said axis, equal to, or substantially equal to, this distance.Furthermore, preferably, in order to ensure a balance of centrifugal forces allowing the aspiration of the first fluid Fl towards the internal volume 20, the primary distance Dkl and the secondary distance Dk2 are equal or substantially equal. As illustrated in [Fig. 6], the spacer 6 thus optionally includes an adjustment portion 63, comprising here the primary outlets of the primary cannulas 71, allowing the radial position of the primary outlets to be moved so as to present a primary distance Dkl equal or substantially equal to the secondary distance Dk2.

[0066] Optionally, regardless of the embodiment implemented, the axial flow electric machine 2 is 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 arrangement and within 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.

[0067] 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 advantageously be without a pump intended to move the first fluid Fl, the primary cannulas 71 and secondary cannulas 6 being suitable for drawing the first fluid Fl into the internal volume 20 of the electric machine 2 as described above.

[0068] Similarly, the second circuit C2 optionally includes a second heat exchanger HX2, located at the front of the vehicle 1 and capable of conducting an exchange thermal between the second fluid F2, for example a coolant, and an outside airflow or a separate coolant, such as water or glycol water.

[0069] The vehicle 1 thus optionally comprises an arrangement 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 heat exchanger HX1. Optionally, such an arrangement further comprises the first circuit Cl, extending at least between the at least one heat exchanger, here the first heat exchanger HX1, and the rotor assembly 4. Optionally again, the arrangement comprises the second circuit C2, configured to allow the circulation of the second fluid F2, and the second heat exchanger HX2.

[0070] In order to allow the separation of the first and second circuits Cl, C2, the electrical machine 2 includes in particular at least one sealing membrane 8 arranged so as to delimit at least one primary compartment 24 and at least one secondary compartment 25. In a known manner, 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 bulk generated within the internal volume 20. It should be noted that the electrical machine 2 can include a plurality of sealing membranes 8. The sealing membrane 8 is arranged so as 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, so as to separate the first space 23a from the stator 3, and a second membrane 8 extends at the level of the second air gap 22b, so as to separate the second space 23b from the stator 3.

[0071] 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 enable the thermal management of said stator 3, particularly its cooling. The housing 21 includes at least one inlet for the second fluid F2 and one outlet for the second fluid F2, not shown, respectively ensuring the supply and discharge of said fluid into the primary compartment 24. For example, a supply hole and a discharge hole for the second fluid F2 are arranged in one of the sides, in particular the first side 21a or the second side 21b, of the housing 21.

[0072] The secondary compartment 25 delimits, for its part, a compartment in which the rotor assembly 4 extends at least in part, 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 which it comprises in parallel with the thermal management of the stator 4.

[0073] 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 distribution channels 5, and the distribution circuit 7 as described above. Part of the flow of the first fluid Fl is sent to the first space 23a through the plurality of primary cannulas 71, while the other part of said flow is sent to the second space 23b through the secondary cannulas 72.The centrifugal force draws the first fluid Fl towards the sides of the casing 21, in particular here towards at least one intermediate side 21c, thus moving it away from the shaft 4L. Such a principle advantageously eliminates the need to integrate a pump into the first circuit CL. The first fluid Fl, thus passing into contact with the magnets 44b of the rotor assembly 4, captures at least some of their heat and allows them to be cooled.

[0074] 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, thus allowing it to cool down. The first fluid Fl, now heated, 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, for example, the intermediate side 21c. The first fluid Fl is then directed to the environment external to the electrical machine 2.

[0075] When the second fluid F2 also circulates in the electric machine 2, as described above, the second fluid F2 is brought into the internal volume 20, in particular into the primary compartment, by at least the supply hole, not shown, located in one of the sides of the housing 21, for example the first side 21a and / or the second side 21b. The second fluid F2 circulates in the primary compartment 24 and absorbs heat from the stator 3, for example from the teeth and coils forming it, thus allowing its cooling. The second fluid F2 is then discharged through the discharge hole, not shown, being, for example, located in one of the sides of the housing 21 of the electric machine 2.The second fluid F2 can then, for example, be returned to the second heat exchanger HX2 where it releases heat to the cooling fluid, allowing it to be cooled before being returned to the internal volume 20 of the casing 21.

[0076] According to an alternative embodiment, not shown, the shaft 41 comprises a plurality of feed ports 43, the feed port 43 described above, located at the first end 41a of the shaft 41, thus forming a first feed port, while a second feed port is included at the level of the second end 41b of the tree 41, opposite the first end 41a. It is understood that the above description applies mutatis mutandis to the present embodiment.

[0077] The invention thus provides a rotor assembly and an electric machine for injecting a fluid, in particular an airflow, into an internal volume of the electric machine in order to allow for the simple and economical thermal management of said rotor. The invention advantageously allows for the injection of an adequate and homogeneous airflow within a given space and on both sides of the rotor assembly's disk, ensuring a balance of fluid flow rates in the various air gaps of the electric machine. The fluid supply can thus be achieved by the rotor assembly and can be adapted to various electric machine architectures. Furthermore, the invention eliminates the need to integrate a pump to move the fluid into the internal volume of the electric machine.

[0078] 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. A rotor assembly (4) for an axial-flow electric machine (2), particularly for an automobile vehicle (1), comprising a disk (44) and a shaft (41) extending along an extension axis (400) on which it is centered, the shaft (41) comprising a bore (42) configured to allow the circulation of a first fluid (Fl), and a plurality of distribution channels (5) for said fluid, connecting the bore (42) to an external periphery (410) of the shaft (41), the rotor assembly (4) further comprising: - a distribution circuit (7) for the first fluid (Fl) disposed around the shaft (41) in fluidic connection with the distribution channels (5), and comprising a plurality of primary cannulas (71) and secondary cannulas (72) configured to allow the circulation of the first fluid (Fl) respectively to a first space (23a) of the electric machine (2), disposed from one side of the rotor disc (44) and towards a second space (23b),arranged on a second side of the disc (44), opposite the first side; - a spacer (6) at least partially disposed between the disc (44) and the outer periphery (410) comprising and / or delimiting at least partially the distribution circuit (7) of the first fluid (Fl); - a base (9), connected to the shaft (41) and extending transversely to the extension axis (400), supporting the disc (44) and comprising and / or delimiting at least partially the distribution circuit (7).

2. Rotor assembly (4) according to the preceding claim, wherein the spacer (6) is an added part made of metallic material, mounted and fixed on the shaft (41) by shrink fitting and / or welding.

3. Rotor assembly (4) according to any one of the preceding claims, wherein the distribution circuit (7) comprises a plurality of bifurcation points (73), at least one pair comprising one of the primary cannulas (71) and one of the secondary cannulas (72) being connected to each of said bifurcation points (73): - the base (9) comprising the bifurcation points (73); or - the spacer (6) delimiting the bifurcation points (73).

4. Rotor assembly (4) according to any one of the preceding claims, wherein the plurality of primary cannulas (71): - is at least partially contained within the spacer (6) and / or delimited by the spacer (6); or - is at least partly contained within the disk (44).

5. Rotor assembly (4) according to any one of the preceding claims, wherein the plurality of secondary cannulas (72): - is at least partly contained within the spacer (6) and / or delimited by the spacer (6); and / or - is at least partly contained within the base (9).

6. Rotor assembly (4) according to any one of the preceding claims, wherein: - the spacer (6) and the base (9) form a single unit, in particular made of a metallic material; or - the base (9) and the shaft (41) form a single unit, in particular made of a metallic material.

7. Rotor assembly (4) according to any one of the preceding claims, wherein: - the secondary cannulas (72) are defined by at least one secondary diameter and the primary cannulas (71) are defined by at least one primary diameter, the at least one secondary diameter being equal to the at least one primary diameter; and / or - the plurality of secondary cannulas (72) comprises a number (kn2) of secondary cannulas (72) equal to a number (knl) of primary cannulas (71) of the plurality of primary cannulas (71).

8. Rotor assembly (4) according to any one of the preceding claims, wherein: - outlets of the primary cannulas (71), opening into the first space (23a), are separated from the extension axis (400) by a primary distance (Dkl), defined along a radial direction from said axis, equal to, or substantially equal to; - outlets of the secondary cannulas (72), opening into the second space (23b), are separated from the extension axis (400) by a secondary distance (Dk2), defined along a radial direction from said axis, equal to, or substantially equal to; - the primary distance (Dkl) and the secondary distance (Dk2) being equal or substantially equal.

9. An axial flux electric machine (2), particularly for a motor vehicle (1), comprising a stator (3), a housing (21) delimiting an internal volume (20), and a rotor assembly (4) according to any one of the preceding claims, the shaft (41) extending through the

10. internal volume (20) such that the primary cannulas (71) and secondary cannulas (72) open into said internal volume (20). Vehicle (1) with electric or hybrid propulsion comprising a rotor assembly (4) according to any one of claims 1 to 8, and / or an electric machine (2) according to claim 9.

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