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 flow of a first fluid (F1), a plurality of primary channels (5) configured to allow the flow of the first fluid (F1) to a first space (23a) disposed on a first side of the disk (44), and a plurality of secondary channels (6) configured to allow the flow of said fluid to a second space (23b) disposed on a second side of the disk (44). Abstract figure: Figure 2

Description

Title of the invention: Rotor assembly for an axial flux electric machine, particularly for motor vehicles, 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. 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, particularly for a motor vehicle, comprising a shaft extending along an extension axis on which it is centered, and a disk comprising at least one magnet, the shaft comprising: - a bore opening at at least one first end of the shaft and configured to allow the circulation of a first fluid; - a plurality of primary channels extending between the bore and an external periphery of the shaft and configured to allow the circulation of the first fluid to a first space of the electrical machine disposed on a first side of the rotor disk; - a plurality of secondary channels, further apart relative to the first end of the shaft than the primary channels, extending between the bore and the outer periphery of the shaft and configured to allow the circulation of the first fluid to a second space of the electric machine, disposed on a second side of the rotor disk opposite the first side.

[0008] In particular: - the primary canals are orthogonal or inclined relative to the extension axis, said primary canals having equal or substantially equal primary inclination angles relative to the extension axis; and / or - the secondary channels are orthogonal or inclined relative to the axis of extension, said secondary channels having secondary angles of inclination equal or substantially equal relative to the axis of extension.

[0009] Optionally, the secondary channels are inclined relative to the extension axis and have a secondary angle of inclination greater than or equal to at least one primary angle of inclination of a primary channel of the plurality of primary channels relative to the extension axis.

[0010] Optionally, secondary channels are defined by at least one secondary diameter and primary channels are defined by at least one primary diameter, the at least one secondary diameter being greater than or equal to the at least one primary diameter.

[0011] In particular, the plurality of secondary channels includes a number of secondary channels greater than or equal to a number of primary channels in the plurality of primary channels.

[0012] According to one embodiment, the tree is dimensioned and shaped such that portions of the tree comprising respectively primary outputs of the primary channels and secondary outputs of the secondary channels are of similar dimensions, in particular diameter, such that: - the primary channels each have a primary distance, separating a primary output of a primary channel considered, located at the level of the outer periphery of the shaft, from the extension axis, equal or substantially equal; - the different secondary channels have a secondary distance, separating an output of a secondary channel considered, located at the level of the outer periphery of the shaft, from the axis of extension, equal or substantially equal; - the primary distance and the secondary distance being equal or substantially equal.

[0013] According to an alternative embodiment, the rotor assembly further comprises an added extension member, having an annular shape and comprising a plurality of cannulas, said member being configured to be disposed on the shaft so that the cannulas extend in continuity with one of the plurality of primary channels or the plurality of secondary channels and such that a distance separating the extension axis from a surface of the extension member comprising effective outlets of the channels considered disposed opposite the extension member, is equal, or substantially equal, to a distance separating the extension axis from a portion of the outer periphery of the shaft comprising effective outlets of the other of the primary or secondary channels.

[0014] The invention also relates to an axial flux electric machine, in particular for a motor vehicle, comprising a casing delimiting an internal volume, a rotor assembly according to the invention and a stator, the shaft extending into the internal volume so that the primary and secondary channels open into said internal volume.

[0015] The invention extends to an arrangement, in particular for a motor vehicle, comprising an electrical machine according to the invention, a first fluid circuit and at least one heat exchanger.

[0016] The invention finally relates to an electric or hybrid motorized vehicle comprising a rotor assembly, an electric machine and / or an arrangement according to the invention.

[0017] 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:

[0018] Fig. 1 is a schematic representation of an embodiment of a vehicle equipped with an electric machine according to the invention.

[0019] Fig. 2 is a schematic cross-sectional representation of an example embodiment of an electrical machine comprising an example embodiment of a rotor assembly.

[0020] Fig. 3 is a schematic representation of a shaft of the rotor assembly.

[0021] Figure 4 is a schematic perspective representation of the tree of the set of rotor.

[0022] Fig. 5 is a schematic cross-sectional representation viewed from above of the tree.

[0023] Figure 6 is a schematic representation of traffic zones of a first fluid in the tree.

[0024] Fig. 7 is a schematic cross-sectional representation of an example embodiment of the electric machine in which the rotor assembly includes an extension element.

[0025] Fig. 8 is a schematic cross-sectional representation of an example embodiment of the electric machine in which the rotor assembly includes a plurality of feed ports.

[0026] 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.

[0027] 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 structural enclosure or casing, 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.

[0028] 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.

[0029] The electrical machine 2 comprises a stator 3 and a rotor assembly 4, configured to be movable relative to the stator 3. In a known manner, 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 The shaft 41 rotates about an axis of rotation, which here coincides with the extension axis 400. It has a cylindrical structure, for example, at least partially circular in base. The shaft 41 extends through at least part 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, machined from a single piece of material.

[0030] 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 41. 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 air flow, as further detailed below. The bore 42 opens at the level of at least one first end 41a of the shaft 41, that is to say it opens towards the environment outside the electrical machine 2 at the level of a supply port 43 for the first fluid Fl allowing the entry of said fluid into the bore 42.The bore 42 extends over at least part 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.

[0031] The rotor assembly 4 also includes a disk 44 carried by the shaft 41 and intended to rotate concurrently 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 arranged in blocks so as to fit within the shape of a disk 44, or substantially a disk.

[0032] 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 shown, fixed within the internal volume 20. In this way, the rotor assembly 4 is displaced in rotation relative to the stator 3.

[0033] In particular, the rotor assembly 4 includes a base 9. 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 44a of the disk 44. To this end, in order to ensure adequate mechanical strength, the base 9 is preferably made of a metallic material, such as steel. In particular, as illustrated, at least a portion of the shaft 41 and the base 9 form a single unit, for example made of a metallic material. "Single unit" means that the elements are made from a single piece of material and cannot be separated from one another without resulting in the degradation, or even destruction, of said elements. Also, the first air gap 22a is located on one side of the base 9 and the second air gap 22b is located on a second side of the base 9, opposite the first side.

[0034] In particular, the shaft 41 of the rotor assembly 4 according to the invention comprises a plurality of primary channels 5 and a plurality of secondary channels 6. Said channels correspond in particular to bores made in the material of the shaft 41. The primary channels 5 and the secondary channels 6 make it possible to 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 the projection of the first fluid Fl towards the internal volume 20 in the vehicle 1. The rotation of the shaft 41 causes a pumping effect, that is to say a suction of the first fluid Fl by means of the bore 42 and of said channels, towards the internal volume 20 by reason of the centrifugal force.

[0035] The primary channels 5 extend between the bore 42 and the outer periphery 410 of the shaft 4L. They are thus configured to allow the circulation of a portion of the first fluid Fl, i.e., the airflow, from the bore 42 to a first space 23a of the electrical machine 2, located on the first side of the rotor disc 44, i.e., here at the level of the first air gap 22a. The primary channels 5 thus form galleries carved into the material of the shaft 41, opening into the bore 42 on one side and outside the shaft 41 on the other.

[0036] The primary channels 5 are arranged so that different primary 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 primary 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 at an equal or substantially equal distance from the first fluid Fl supply port 43, said distance being evaluated along the first direction 100.

[0037] Similarly, primary outputs specific to the different primary channels 5 are arranged in particular in the outer periphery 410 of the shaft 4L. In particular, preferably, the primary outputs 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 in the first fluid Fl.

[0038] Optionally but preferably, the various primary channels 5 are straight. Also, the primary 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 in the first space 23a during the operation of the electrical machine 2. In particular, at least the primary outlets are distributed regularly within the outer periphery 410 of the shaft 41. Optionally but preferably, the primary inlets of the primary channels 5 are distributed regularly within the inner periphery 411 of the shaft 41 and the primary outlets are distributed regularly 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.

[0039] The secondary channels 6 are arranged in the shaft 41 so as to be further away from the first end 41a of the shaft 41 and from the first fluid supply port 43 Fl than the primary channels 5. In other words, a distance measured along the extension axis 400 between the secondary channels 6 and the supply port 43 is strictly greater than a distance measured between the primary channels 5 and said supply port 43.

[0040] Similar to the primary channels 5, the secondary channels 6 extend between the bore 42 and the outer periphery 410 of the shaft 41. The secondary channels 6 thus form galleries cut into the material of the shaft 41 opening into the bore 42 on one side and outside the shaft 41 on the other. They are configured to allow the circulation of a portion of the first fluid Fl, i.e., the airflow, from the bore 42 to a second space 23b of the electrical machine 2, distinct from the first space 23a, located on the second side of the rotor disk 44, i.e., in the second air gap 22b, 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.The first fluid flow Fl is thus divided into two, a first part being distributed towards the first space 23a via the primary channels 5 and a second part being distributed towards the second space 23b via the secondary channels 6.

[0041] The secondary channels 6 are arranged in particular so that different secondary inlets of the first fluid Fl, specific to said channels, are arranged in the inner periphery 411 of the shaft 41, delimiting the bore 42. In particular, said secondary inlets are arranged in a circular or substantially circular shape circular, crossed by at least one common plane, distinct from the plane proper to the primary channels 5, 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 first fluid supply orifice 43 Fl.

[0042] Similarly, secondary outlets specific to the different secondary channels 6 are in particular arranged in the outer periphery 410 of the shaft 41. In particular, preferably, the secondary outlets are arranged in a circular or substantially circular shape, crossed by at least one common plane distinct from the plane specific to the primary channels 5, 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 first fluid supply port 43 Fl.

[0043] Optionally but preferably, the various secondary channels 6 are straight. Also, the secondary channels 6 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 in the second space 23b during the operation of the electrical machine 2. In particular, at least the secondary outlets are distributed regularly within the outer periphery 410 of the shaft 41. Optionally but preferably, the secondary inlets of the secondary channels 6 are distributed regularly within the inner periphery 411 of the shaft 41 and the secondary outlets are distributed regularly within the outer periphery 410 of the shaft 41, the secondary channels 6 thus extending radially from the extension axis 400 at regular intervals around the circumference of the shaft 41.

[0044] Figure 6 schematically illustrates the circulation zones of the first fluid through the bore, the primary channels 5 and the secondary channels 6, the material of the shaft 41 being removed here for clarity.

[0045] Preferably, the primary channels 5 are arranged so as to extend orthogonally relative to the extension axis 400 or so as to be inclined relative to the extension axis 400. In particular, the primary channels 5 are each arranged so as to have a primary angle of inclination al, relative to the extension axis 400, greater than or equal to 90°, the inclination of said channels being such that the primary outlet of a primary channel 5 considered is further from the first fluid supply port 43 Fl than the primary inlet of said primary channel 5 along the first direction 100 when the primary angle of inclination al is strictly greater than 90°.

[0046] In particular, in order to ensure a homogeneous flow rate of the first fluid Fl between the different primary channels 5, these are arranged so as to have equal or substantially equal primary angles of inclination al. For example, the The primary inclination angles al of the primary channels 5 are between 90° and 160°, or even between 90° and 145°. As explained further below, the greater the primary inclination angle al of a primary channel, the more facilitated the circulation of the first fluid Fl from the bore 42.

[0047] A similar principle applies, mutatis mutandis, to the secondary channels 6. Also, alternatively or additionally, preferably, the secondary channels 6 are arranged so as to extend orthogonally relative to the extension axis 400 or so as to be inclined relative to the extension axis 400. In particular, the secondary channels 6 are arranged so as to each have an angle, relative to the extension axis 400, greater than or equal to 90°, the inclination of said channels being such that the secondary outlet of a secondary channel 6 considered is further from the first fluid supply port 43 Fl than the secondary inlet of said secondary channel when the secondary angle of inclination a2 is strictly greater than 90°.

[0048] In particular, to ensure a homogeneous flow rate of the first fluid Fl between the various secondary channels 6, these are arranged so as to have equal or substantially equal secondary inclination angles α2. For example, the secondary inclination angles α2 of the secondary channels 6 are between 90° and 160°, or even between 90° and 145°. The secondary channels 6 are then arranged at a secondary inclination angle α2 greater than or equal to a primary inclination angle α1 of the primary channels 5, relative to the extension axis 400.

[0049] To ensure optimal cooling of the rotor assembly 4, it is preferable to implement homogeneous cooling of its various components. Therefore, to optimize the homogeneity of the first fluid flow rate Fl between the primary channels 5 on the one hand and the secondary channels 6 on the other, and by extension, the homogeneity of the first fluid flow rate Fl between the first space 23a and the second space 23b, various embodiments can be implemented.

[0050] According to a first embodiment, the secondary channels 6 are inclined relative to the extension axis 400 and each has secondary inclination angles α2 strictly greater than the primary inclination angles α1 of the primary channels 5 relative to the extension axis 400. This principle extends to secondary channels 6 having equal or substantially equal secondary inclination angles α2 and / or to primary channels 5 having equal or substantially equal primary inclination angles α1 as described above. This principle ensures that the first fluid λ flows through the secondary channels 6, which are further from the feed orifice 43 than the primary channels 5, at a flow rate close to, or even equal to, that of the first fluid λ flowing in the primary channels 5.

[0051] According to a second embodiment, alternative to or compatible with the first embodiment, the secondary channels 6 are defined by at least one secondary diameter and the primary channels 5 are defined by at least one primary diameter, the at least one secondary diameter being greater than or equal to the at least one primary diameter. Optionally, but preferably, to ensure a homogeneous distribution of the first fluid Fl in the first space 23a, the various primary channels 5 have equal, or substantially equal, primary diameters. Similarly, to ensure a homogeneous distribution of the first fluid Fl in the second space 23b, the various secondary channels 6 have equal, or substantially equal, secondary diameters. Also, preferably, the secondary diameter of the various secondary channels 6 is strictly greater than the primary diameter of the primary channels 5.

[0052] According to a third embodiment, alternative to or able to be combined with the first embodiment and / or the second embodiment, the plurality of secondary channels 6 comprises a number kn2 of secondary channels 6 greater than or equal to a number knl of primary channels 5 of the plurality of primary channels 5. Similar to the first embodiment and the second embodiment, such a principle aims to ensure that a flow rate of the first fluid Fl distributed in the first space 23a via the primary channels 5 and a flow rate of the first fluid Fl distributed in the second space 23b, further from the supply port 43, via the secondary channels 6 is close, or even equal.

[0053] In order to balance the flow of the first fluid Fl implemented, the shaft 41 can also be particularly configured so that the pump effect allowing the suction of air towards the first space 23a and the second space 23b by centrifugal force is balanced on each side of the disk 44.

[0054] To this end, it is preferable that the primary outputs of the various primary channels 5, contained within the outer periphery 410 of the shaft 41, extend to a primary distance Dkl equal to or substantially equal to the extension axis 400, as shown in Figures 2 to 6. This primary distance Dkl is defined radially from the extension axis 400, along an axis orthogonal to the extension axis, and passes through each primary output. The same applies to the secondary outputs of the various secondary channels 6, which extend to a secondary distance Dk2 equal to or substantially equal to the extension axis 400. Optionally, but preferably, the primary distance Dkl and the secondary distance Dk2 are equal or substantially equal.

[0055] In particular, according to an example of an embodiment not shown, which can be implemented with the various example embodiments described above, the tree 41 is dimensioned and shaped so that the primary distance Dkl specific to the channels The primary channel 5 is equal to or substantially equal to the secondary channel 6 distance Dk2. In such an embodiment, the portions of the shaft 41 comprising the primary and secondary outputs are thus of similar dimensions, particularly diameters. The centrifugal force acting on the primary channel 5 and the secondary channel 6 is therefore similar.

[0056] In other words, a primary distance Dkl separating a first portion of the outer periphery 410 of the shaft 41, comprising primary outputs of the primary channels 5, is constant or substantially constant relative to the extension axis 400, said distance being defined radially from said axis, a secondary distance Dk2 separating a second portion of the outer periphery 410 of the shaft 41, comprising secondary outputs of the primary channels 5, is constant or substantially constant relative to the extension axis 400, the primary distance Dkl being equal or substantially equal to the secondary distance Dk2.

[0057] Such a principle makes it possible to ensure that the pumping, or suction, effect of the first fluid Fl linked to the centrifugal force implemented during the rotation of the shaft 41 is balanced between the first space 23a and the second space 23b, which makes it possible to optimize the thermal management of the rotor assembly 4 on both sides of the disk 44.

[0058] Alternatively, as illustrated in [Fig. 7], when the portion of the shaft 41 comprising the primary channels 5 and the portion of the shaft 41 comprising the secondary channels 6 do not have similar dimensions, i.e., when the outer periphery 410 included in said portions extends at different distances from the extension axis 400 from one portion to the other, the rotor assembly 4 optionally and advantageously includes an extension member 7 disposed on the shaft 41. The extension member 7 has an annular shape and includes a plurality of cannulas 71 extending between an inner face 70a, configured to be turned towards the outer periphery 410 of the shaft 41, and an opposite outer face 70b.The cannulas 71 are configured to extend in relation to the primary channels 5 or the secondary channels 6, that is to say in continuity with them, when the extension member 7 is disposed on the shaft 41 so as to compensate for a difference in the dimension of the shaft 4L. In other words, the extension member 7 is able to move the radial position of the primary outlets or the secondary outlets by extending the channels in question disposed in the shaft 41 so as to present an equal distance, relative to the extension axis 400, between an effective outlet of the first fluid flowing in the primary channels 5 and an effective outlet of said fluid flowing in the secondary channels 6. The "effective outlet" is here defined as the area at which the first fluid Fl exits the rotor assembly 4 to enter the first space 23a or the second space 23b.The first fluid Fl then flows through the bore 42, the primary channels 5 or the secondary channels 6. depending on the position of the extension organ 7, then the cannulas 71 of said organ before actually exiting into the first space 23a or into the second space 23b.

[0059] Thus, when the extension member 7 is disposed on the shaft 41 at the level of one of the primary channels 5 or the secondary channels 6, the internal surface 70a of said member extends in contact with the external periphery 410 of the shaft 41 and the external surface 70b of said extension member 7 is disposed at a distance equal or substantially equal to a distance from the external periphery 410 of a portion of the shaft comprising the outlets of the other of the primary channels 5 or the secondary channels 6. Said distances are then evaluated relative to the extension axis 400, along radial directions originating from said axis, in planes orthogonal to the extension axis 400.

[0060] In this case, in the illustrated example, the extension member 7 is arranged on the shaft 41 so that the cannulas 71 extend in continuity with the primary channels 5, such that an effective primary distance Dkel separating the extension axis 400 from an effective outlet of a primary channel 5, located at the level of the external surface 70b of the extension member 7, is equal to, or substantially equal to, a secondary distance Dk2 separating the extension axis 400 from an outlet of a secondary channel 6, located at the level of the external periphery 410 of the shaft 41. Such a principle extends to the different channels as described above and applies mutatis mutandis to an extension member 7 arranged at the level of the secondary channels 6.

[0061] 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.

[0062] 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 duct 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 channels 5 and secondary channels 6 being suitable for drawing the first fluid Fl into the internal volume 20 of the electric machine 2 as described above.

[0063] 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.

[0064] 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 includes the second circuit C2, configured to allow the circulation of the second fluid F2, and the second heat exchanger HX2.

[0065] 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.

[0066] 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.

[0067] The secondary compartment 25, for its part, delimits a compartment in which the rotor assembly 4 extends, including at least a portion of the shaft 41 and the disc 44. The first fluid Fl thus ensures 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.

[0068] 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. Part of the flow of the first fluid Fl is sent to the first space 23a through the plurality of primary channels 5, while the other part of said flow is sent to the second space 23b through the secondary channels 6. Indeed, when the shaft 41 of the rotor assembly 4 is rotated, the latter generates a pressure difference between a zone radially close to the shaft 41 and a zone radially further away relative to the extension axis 400.Also, the centrifugal force draws the first fluid Fl towards the first space 23a and the second space 23b, that is to say, it displaces the first fluid Fl towards the sides of the housing 21, in particular here towards at least one intermediate side 21c, thus moving it away from the shaft 41. 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.

[0069] 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 fluid Fl, thus 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.

[0070] 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, through at least one supply hole, not shown, located in one of the sides of the casing 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, located, for example, in one of the sides of the casing 21 of the electric machine 2. The second fluid F2 can then, for example, be returned to the second heat exchanger HX2 at which it releases heat to the cooling fluid, allowing it to be cooled before it is returned to the internal volume 20 of the casing 21.

[0071] Figure 8 illustrates an example of an alternative embodiment, in which 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 43a, while a second feed port 43b is included at the second end 41b of the shaft 41, opposite the first end 41a. It is understood that the above description applies mutatis mutandis to the present embodiment.

[0072] In the present embodiment, the first circuit Cl is connected to the first feed port 43a and the second feed port 43b and is capable of supplying the first fluid Fl to the opposite ends of the shaft 41. According to an embodiment not shown, the bore 42 extends continuously between the first feed port 43a and the second feed port 43b. In other words, said ports are in fluidic connection via the bore 42. Alternatively, as illustrated in [Fig. 8], the bore 42 is divided into two distinct, separate portions, each connected to one of the feed ports 43.A first portion of the bore 42 then includes the first feed orifice 43a and is connected to the primary channels 5 opening into the first space 23a while a second portion of the bore 42 includes the second feed orifice 43b and is connected to the secondary channels 6 opening into the second space 23b. .

[0073] The above description, relating to variations in dimensions, inclinations, and number of channels, applies here mutatis mutandis, this time with respect to the nearest feed orifice 43 for each plurality of channels considered. For example, without limitation, in the case of a bore 42 divided into two portions, if the distance separating the secondary channels 6 from the second feed orifice 43b is strictly greater than the distance separating it from the first feed orifice 43a, the number of secondary channels may be greater than the number of primary channels 5 and / or the secondary channels 6 may have diameters greater than the diameters of the primary channels 5.

[0074] 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 a homogeneous flow on both sides of the rotor assembly's disk, while ensuring a balance of fluid flow rates in the various air gaps of the electric machine. The fluid supply can thus be achieved by a single component and can be adapted to various machine architectures. electric. The invention also eliminates the need to integrate a pump to move the fluid towards the internal volume of the electric machine.

[0075] 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 an automobile vehicle (1), comprising a shaft (41) extending along an extension axis (400) on which it is centered, and a disk (44) having at least one magnet, the shaft (41) comprising: - a bore (42) opening at at least a first end (41a) of the shaft (41) and configured to allow the circulation of a first fluid (Fl); - a plurality of primary channels (5) extending between the bore (42) and an external periphery (410) of the shaft (41) and configured to allow the circulation of the first fluid (Fl) to a first space (23a) of the electric machine (2) disposed on a first side of the disk (44) of the rotor;- a plurality of secondary channels (6), further apart relative to the first end (41a) of the shaft (41) than the primary channels (5), extending between the bore (42) and the outer periphery (410) of the shaft (41) and configured to allow the circulation of the first fluid (Fl) to a second space (23b) of the electric machine (2), disposed on a second side of the rotor disk (44) opposite to the first side.;

2. Rotor assembly (4) according to the preceding claim, wherein: - the primary channels (5) are orthogonal or inclined relative to the extension axis (400), said primary channels (5) having primary inclination angles (al1) equal or substantially equal relative to the extension axis (400); and / or - the secondary channels (6) are orthogonal or inclined relative to the extension axis (400), said secondary channels (5) having secondary inclination angles (a2) equal or substantially equal relative to the extension axis (400).

3. Rotor assembly (4) according to the preceding claim, wherein the secondary channels (6) are inclined relative to the extension axis (400) and have a secondary tilt angle (a2) greater than or equal to at least a primary tilt angle (al) of one primary channel (5) of the plurality of primary channels (5) relative to the extension axis (400).

4. Rotor assembly (4) according to any one of the preceding claims, wherein the secondary channels (6) are defined by at least one secondary diameter and the primary channels (5) are defined by at least one primary diameter, the at least one secondary diameter being greater than or equal to the at least one primary diameter.

5. Rotor assembly (4) according to any one of the preceding claims, wherein the plurality of secondary channels (6) comprises a number (kn2) of secondary channels (6) greater than or equal to a number (knl) of primary channels (5) of the plurality of primary channels (5).

6. Rotor assembly (4) according to any one of the preceding claims, wherein the shaft (41) is dimensioned and shaped such that portions of the shaft (41) comprising respectively primary outputs of the primary channels (5) and secondary outputs of the secondary channels (6) are of similar dimensions, in particular diameter, such that: - the primary channels (5) each have a primary distance (Dkl), separating a primary output of a considered primary channel (5), located at the outer periphery (410) of the shaft (41), from the extension axis (400), equal or substantially equal; - the various secondary channels (6) have a secondary distance (Dk2), separating an output of a considered secondary channel (6), located at the outer periphery (410) of the shaft (41), from the extension axis (400), equal or substantially equal; - the primary distance (Dkl) and the secondary distance (Dk2) being equal or approximately equal.

7. A rotor assembly (4) according to any one of claims 1 to 5, further comprising an added extension member (7), having an annular shape and comprising a plurality of cannulas (71), said member being configured to be disposed on the shaft (41) such that the cannulas (71) extend in continuity with one of the plurality of primary channels (5) or the plurality of secondary channels (6) and such that a distance separating the extension axis (400) from a surface (70b) of the extension member (7) comprising effective outlets of the channels considered disposed opposite the extension member (7), is equal to, or substantially equal to, a distance separating the extension axis (400) from a portion of the outer periphery (410) of the tree (41) comprising effective outputs from the other of the primary channels (5) or secondary channels (6).

8. An axial flux electric machine (2), in particular for a motor vehicle (1), comprising a casing (21) delimiting an internal volume (20), a rotor assembly (4) according to any one of the preceding claims and a stator (3), the shaft (41) extending into the internal volume (20) such that the primary channels (5) and the secondary channels (6) open into said internal volume (20).

9. Arrangement, in particular for a motor vehicle (1), comprising an electrical machine (2) according to the preceding claim, a first fluid circuit (Fl) and at least one heat exchanger.

10. Vehicle (1) with electric or hybrid motorization comprising a rotor assembly (4) according to any one of claims 1 to 7, an electric machine (2) according to claim 8 and / or an arrangement according to claim 9.

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