Electric machine comprising tilting blades

Abstract

Electric machine comprising tiltable vanes. The invention relates to an electric machine comprising a stator (2) and a rotor (3) comprising at least one first vane (28) extending from a first face (32) of the rotor towards the stator along a first radial axis (L1), the stator comprising at least one second vane (29) extending from a second face (22) of the stator towards the rotor along a second radial axis (L2), the first and second vanes being rotatable about one of the respective radial axes (L1, L2) between an inclined position in which the first and second vanes form an angle with each other and a non-inclined position in which the first and second vanes are parallel, the inclination between the first and second vanes increasing with the air density when the rotor is in motion. Figure for the abstract: Fig. 4.

Description

Title of the invention: Electric machine comprising tiltable vanes. Technical field

[0001] The invention relates to the field of cooling electrical machines and electronic components of electrical machines such as power modules. The invention relates to an electrical machine and an aircraft comprising such an electrical machine. Previous technique

[0002] The present invention can be used, in particular, in the aeronautical field for electrical machines intended for propulsive or non-propulsive applications on board an aircraft, for example. The electrical machine is notably usable in an electromechanical actuation system.

[0003] An electrical machine classically comprises a stator and a rotor having an axis of rotation. The stator has a central circular opening, a plurality of teeth extending in the central circular opening in a radial direction of the stator, a plurality of power sets each comprising a coil wound around one of the teeth and a coil support supporting the power sets.

[0004] Electrical machines are configured in such a way that a maximum temperature is reached very quickly at the end of their operation, for example after a few minutes, which leads to a limitation of the performance of these electrical machines.

[0005] Indeed, the torque performance of the electric machine is difficult to improve without increasing the current intensity, but such an increase risks raising the temperature of the electric machine to unacceptable levels, leading to a decrease in the machine's performance, or even its destruction. Operating at higher temperatures also increases the carbon footprint.

[0006] The electric machine also includes power assemblies, each comprising a power module, which allows the electric machine to be supplied with electrical energy from the main network.

[0007] In order to improve the compactness and performance of electrical systems, the power modules can be integrated into the electrical machine, between the rotor and the stator, by being supported by an internal surface of the stator positioned opposite the rotor or by an external surface of the stator positioned opposite a housing containing the rotor and the stator, for example.

[0008] However, the power modules may include within them heat sources which need to be cooled in order not to damage the equipment and to allow good operating efficiency.

[0009] Solutions exist that utilize a heat exchanger comprising a first face mounted in contact with the power modules and a second face opposite the first, defining an annular volume with the rotor through which a cooling fluid circulates by convection from the second face of the exchanger. The fluid can be air. The rotation of the air within the annular volume, driven by the rotor, increases the heat exchange between the air and the heat exchanger.

[0010] It is known to use annular heat exchangers comprising straight fins arranged perpendicular to the axis of rotation of the rotor. The fins allow cooling by radiation and convection.

[0011] However, straight fins are most effective when the fluid flow is directed along the fins. During operation, the rotor induces rotating flows between the rotor and the heat exchanger. These flows can exhibit variations in inclination, which impacts the efficiency of heat exchange between the fins and the fluid. Therefore, there is a need to improve heat exchange in the context of a convective environment with a rotating fluid.

[0012] Moreover, this type of solution is suitable for locally cooling power modules but does not allow cooling of other areas of the electrical machine such as the teeth.

[0013] Furthermore, it was observed that the efficiency of heat exchange between the fins and the fluid differed at low and high altitudes. Heat exchange efficiency is significantly greater at low altitudes than at high altitudes, despite a much lower temperature at high altitudes than at low altitudes. The difference in efficiency can be 40%, for example. This difference is explained by a lower air density at high altitudes than at low altitudes. The air head is lower at high altitudes, making heat exchange by convection less efficient. Description of the invention

[0014] The objective of the present invention is to solve at least partially these problems and to provide an electrical machine in which the cooling between the rotor and the stator is improved.

[0015] The present invention relates to an electrical machine comprising a stator and a rotor having an axis of rotation, one of the stator or the rotor surrounding the other of the stator or the rotor such that an annular volume is formed between the stator and the rotor. The stator includes a yoke having a plurality of teeth extending radially within the annular volume, a plurality of power assemblies each comprising a coil wound around one of the teeth and a coil support supporting the power assemblies, each power assembly comprising a power module positioned on an internal face of the stator, inside the annular volume, and configured to supply the coil with current.

[0016] The rotor comprises at least one first blade extending within the annular volume from a first face of the rotor towards the stator along a first radial axis. The stator comprises at least one second blade extending within the annular volume from a second face of the stator towards the rotor along a second radial axis. The first and second blades are rotatable about their respective radial axes, between an inclined position in which the first and second blades form an angle with each other and a non-inclined position in which the first and second blades are parallel. The inclination between the first and second blades increases with air density when the rotor is in motion.

[0017] The invention thus provides an electric machine in which the cooling between the rotor and the stator is improved.

[0018] This solution improves the cooling of the annular volume between the stator and rotor of a moving electrical machine by 75%, both at low and high altitudes where the air is less dense. Convective cooling is favored at low altitudes, and radiative cooling is favored at high altitudes.

[0019] The torque performance of the electric machine can thus be improved by increasing the current intensity, significantly limiting the risk of the electric machine's temperature rising to unacceptable levels. The risk of reduced performance or even destruction of the electric machine is limited. The carbon footprint is also reduced.

[0020] According to one variant, the first and second fins each comprise a central portion positioned between two lateral portions, the two lateral portions being made of a shape memory material.

[0021] According to one variant, the two lateral portions are made of nickel-titanium.

[0022] According to one variant, the rotor comprises at least a first row formed of several first fins, the stator comprising at least a second row formed of several second fins.

[0023] According to one variant, the teeth comprise a radially internal face having at least a second row of second fins.

[0024] According to one variant, each power module includes a radially internal face having at least a second row of second fins.

[0025] The invention makes it possible to cool power modules positioned between the rotor and the stator as efficiently at low as at high altitude.

[0026] According to one embodiment, the rotor includes a mobile ventilation device rotating relative to the stator, positioned at a first end of the electric machine and configured to generate a fluid flow in the annular volume from a longitudinal inlet of the annular volume positioned at the first end of the electric machine to a longitudinal outlet of the annular volume positioned at a second end of the electric machine, opposite the first end.

[0027] The coils and power modules positioned between the rotor and the stator are thus cooled more efficiently by convection.

[0028] According to one embodiment, the coil support comprises at least one main channel extending longitudinally in the coil support from an inlet of the main channel positioned at a first end of the coil support to an outlet of the main channel opening at a second end of the coil support, opposite the first end, the inlet being in fluidic communication with the annular volume.

[0029] Thus, a first portion of the fluid circulates in the annular volume and a second portion of the fluid circulates in the main channel, helping to reduce the pressure induced by the small spacing in the annular volume and improving the flow rate. The coils and power modules are therefore cooled more efficiently by convection.

[0030] The invention also relates to an aircraft comprising an electrical machine as defined above. Brief description of the drawings

[0031] The invention and its advantages will be better understood upon reading the following detailed description of various embodiments of the invention, given by way of non-limiting examples. This description refers to the accompanying figures, in which:

[0032] [Fig-1] Fig. 1 schematically represents an example of an electrical machine including a ventilation device according to the invention,

[0033] [Fig.2] [Fig.2] schematically represents the interior of the electrical machine of [Fig.1] comprising a rotor equipped with first blades,

[0034] [Fig.3] [Fig.3] schematically represents the interior of a stator of the electrical machine of [Fig.1] equipped with second fins,

[0035] [Fig.4] Fig.4 schematically represents the first and second fins formed on the rotor and stator respectively, when they are inclined,

[0036] [Fig.5] Fig.5 schematically represents a front view of a first or second rotating movable fin,

[0037] [Fig.6] Fig.6 schematically represents a top view of the first fin parallel to the second fin when the air density is low,

[0038] [Fig.7] Fig.7 schematically represents a top view of the first fin angled relative to the second fin when air density is higher. Description of the implementation methods

[0039] Figures 1 and 2 schematically represent an example of an electrical machine 1 comprising a stator 2 and a rotor 3 rotating about an axis of rotation X and relative to the stator 2. One of the stator 2 or of the rotor 3 comes around the other of the stator 2 or of the rotor 3 so that an annular volume 4 is arranged between the stator 2 and the rotor 3. In the example of [Fig. 1], the stator 2 surrounds the rotor 3.

[0040] The electric machine 1 can be used in the aeronautical field for electric machines 1 intended for propulsive or non-propulsive applications on board an aircraft, for example. The electric machine 1 is particularly usable in an electromechanical actuation system of an aircraft element such as a rudder, a nozzle, a brake, a flap or an airbrake, for example.

[0041] As illustrated in Figures 2 and 3, the stator 2 has a central circular opening 16, a yoke 36 having a plurality of teeth 17 extending in the central circular opening 16 in a radial direction of the stator 2, a plurality of power sets 18 each having a coil 19 wound around one of the teeth 17 and a coil support 21 supporting the power sets 18. The coil support 21 at least partially encompasses the coil 19.

[0042] Each power assembly 18 comprises a power module 20 supported by the stator 2 and configured to supply current to the coil 19. The power modules 20 are positioned on a second face 22 of the stator 2, opposite the rotor 3, and positioned at a first end 26 of the coil support 21. The second face 22 of the stator 2 is partly formed by an inner face 46 of the power assemblies 18 and an inner face 45 of the teeth 17.

[0043] The power modules 20 supply electrical energy to the electric machine 1 from the main grid. The power modules 20 can advantageously be distributed circumferentially, in particular regularly, around the axis of rotation X.

[0044] The electric machine 1 includes a first bearing 7a positioned at a first end 8a of the electric machine 1 and a second bearing 7b positioned at a second end 8b of the electric machine 1, opposite to the first end 8a.

[0045] The electric machine 1 includes a housing 13 in which the stator 2 and the rotor 3 are housed. The housing 13 includes a first housing 14a housing the first bearing 7a and a second housing 14b housing the second bearing 7b.

[0046] The rotor 3 includes a shaft 9 passing through the first and second housings 14a, 14b.

[0047] The rotor 3 includes magnets 15 fixed on the shaft 9 and distributed circumferentially around the shaft 9. The magnets 15 are positioned inside the stator 2. The volume between the magnets 15 and the second face 22 of the coil support 21 defines the major part of the annular volume 4.

[0048] As illustrated in Figures 2 to 4, the rotor 3 comprises at least a first row 30 of first fins 28 extending from a first face 32 of the rotor 3 towards the stator 2. The stator 2 comprises at least a second row 31 of second fins 29 extending from the second face 22 of the stator 2 towards the rotor 3. The first fins 28 cross and run alongside the second fins 29 when the rotor 3 is in motion. The first fins 28 and the second fins 29 are positioned within the annular volume 4. When the rotor 3 is in motion, the first fins 28 and the second fins 29 overlap or intersect. The first fins 28 and the second fins 29 are close but offset so as not to collide and so as to create a venturi effect.

[0049] Each fin 28, 29 has a length along its associated radial axis L1, L2 that is less than the width of the annular space 4. The fins 28, 29 have a length between 5.3 mm and 7 mm, a width of approximately 1.5 mm, and a thickness of less than 1 mm, for example. The lengths of the first fins 28 and the second fins 29 are defined such that when two fins 28, 29 intersect, the first fin 28 runs alongside the second fin 29 along the direction of the radial axes L1, L2 for at least one-quarter of the length of the first fin 28, and the second fin 29 runs alongside the first fin 28 for at least one-quarter of the length of the second fin 29.

[0050] The gap between the first fins 28 and the second fins 29 is less than the height of the fins. For example, for two fins 28, 29 each having a height of 5 mm, the gap between these fins 28, 29 is less than 5 mm.

[0051] When the electric machine 1 comprises several first rows 30 of first fins 28 and several second rows 31 of second fins 29, a first row 30 of first fins 28 passes between two second rows 31 of second fins 29. Similarly, a second row 31 of second fins 29 passes between two first rows 30 of first fins 28.

[0052] As illustrated in [Fig. 2], the rotor 3 comprises several rows 30 of first vanes 28 projecting from the surface of the magnets 15. In this example, the rotor 3 comprises ten rows 30 of first fins 28 spaced at equal distances from each other. Within each first row 30, the first fins 28 are evenly distributed around the magnets 15. The surface of the magnets 15 is almost entirely covered by first fins 28.

[0053] The first fins 28 extend perpendicularly with respect to the first face 32 of the rotor 3 along a first radial axis L1 which is perpendicular to the axis of rotation X. The second fins 29 extend perpendicularly with respect to the second face 22 of the stator 2 along a second radial axis L2 which is perpendicular to the axis of rotation X. The first and second longitudinal axes L1, L2 are parallel.

[0054] The first fins 28 and the second fins 29 are made of metal and have a flat shape, with an oblong or rectangular section, for example.

[0055] As illustrated in the example in [Fig. 3], the inner face 45 of each tooth 17 comprises these second rows 31 of second fins 29. Each second row 31 comprises three second fins 29. The inner face 46 of each power module 20 comprises a single second row 31 of second fins 29. Each second row 31 positioned on the power modules 20 comprises five second fins 29. The number of second rows 31 can vary on the teeth 17 and on the power modules 20 according to the heat dissipation requirements.

[0056] The first fins 28 extend along a first plane perpendicular to the axis of rotation X. The second fins 29 extend along a second plane perpendicular to the axis of rotation X.

[0057] The first fins 28 can extend directly from the magnets 15 or from a support surrounding the magnets 15 and in contact with the magnets 15. The second fins 29 can extend directly from the inner face 45 of each tooth 17 or from a support in contact with the inner face 45. The second fins 29 can extend directly from the inner face 46 of each power module 20 or from a support in contact with the inner face 46.

[0058] The first and second fins 28, 29 are rotatable about their respective radial axes L1, L2 between an inclined position ([Fig. 7]) in which the first and second fins 28, 29 form an angle with each other at least when positioned opposite each other, and a non-inclined position ([Fig. 6]) in which the first and second fins 28, 29 are substantially parallel to each other at least when positioned opposite each other. The first fins 28 are rotatable about the first radial axis L1. The second fins 29 are rotatable about the second radial axis L2.

[0059] A tilt angle is formed between the first and second vanes 28, 29 from an air density threshold and when the rotor 3 is rotating. The angle The angle of inclination between the first and second blades 28, 29 increases as air density increases. The angle of inclination also increases as the rotational speed of the rotor 3 increases in the presence of sufficient air density, at low or medium altitudes.

[0060] The maximum tilt angle is reached for ambient air density at ground level. "Ground" is understood to mean ground that can be positioned substantially at sea level, below sea level, or above sea level. The first fins 28 are tiltable relative to the second fins 29. The fin tilt angle varies according to the air density and is between 0° and 80° in absolute value.

[0061] The deformation of the first and second fins 28, 29 occurs mainly between the ground and an altitude of about 2 km, corresponding to an air pressure varying substantially between 1000 Hpa and 800 Hpa.

[0062] When the air density is low, the angle of inclination is equal to 0°.

[0063] In the rest position, when the aircraft's electrical machine 1 is stopped, the first and second fins 28, 29 are initially parallel to each other.

[0064] When the electric machine 1 is running and the aircraft is moving at an ambient air density, during takeoff, for example, the angle of inclination between the first and second fins 28, 29 is at its maximum.

[0065] When the first fins 28 cross the second fins 29 during the rotation of the rotor 3, a venturi channel is formed between the first and second fins 28, 29.

[0066] Fig. 4 illustrates three first rows 30 of first fins 28 crossing three second rows 31 of second fins 29 when the fins 28, 29 are inclined, by way of example.

[0067] When the first fins 28 are in motion and cross the second fins 29, an alternation of first rows 30 of first fins 28 and second rows 31 of second fins 29 is formed.

[0068] During the crossing of the first and second rows 30, 31 of fins, a situation of significant turbulence is created, accelerated in convection by the venturi channel while promoting significant radiative exchange, due to the proximity and length of the fins 28, 29.

[0069] When the aircraft gains altitude, the air becomes thinner and the angle of inclination between the first and second vanes 28, 29 decreases for a given rotational speed of the rotor 3. The angle of inclination also changes as a function of the speed of the rotor 3 since the airflow inside the annular volume 4 increases with the speed of the rotor 3.

[0070] In other words, the angle of inclination between the first and second fins 28, 29 increases when the mass flow of air, arriving on the leading edges 49 of the fins 28, 29, increases.

[0071] In the absence of air, the stress on the first and second fins 28, 29 is almost zero.

[0072] As illustrated in [Fig. 5], the first and second fins 28, 29 each comprise a central metal portion 47 connected to two lateral portions 48. The central portion 47 is positioned between the two lateral portions 48. The two lateral portions 48 are made of a shape-memory material, which may be nickel-titanium, for example. Nitinole or any other type of alloy with nickel and titanium as the main constituents, in almost equal proportions, may be used.

[0073] The central portion 47 is not composed of a shape memory material.

[0074] The two lateral portions 48 are passively deformable (without energy input) depending on the air density.

[0075] In a vacuum or near-vacuum, the first and second fins 28, 29 are parallel to each other, as illustrated in [Fig. 6]. Cooling is mainly achieved by thermal radiation between the first and second fins 28, 29 and a temperature uniformly distributed over the first and second fins 28, 29.

[0076] In the presence of air, the first and second fins 28, 29 are inclined, as illustrated in [Fig. 7]. A leading edge 49 of the fin 28, 29, which is the first edge in contact with the airflow, is at a different (higher) temperature than a trailing edge 50, opposite the leading edge 49. This creates a temperature difference inside the fin 28, 29, causing the leading edge 49 to rotate and deform. This rotation allows the leading edge 49 to return to lower temperatures. Nitinole transitions from the austenitic to the martensitic phase.

[0077] The deformation of the fins 28, 29 also allows for the creation of forced convection by the formation of vortices and volutes between the fins 28, 29, improving heat transfer through an association of heat transfer by conduction, radiation and convection.

[0078] The inclination of the fins 28, 29 is at its maximum during the aircraft's flight phases close to the ground, such as during takeoff and landing, i.e., when the electric machine 1 is under heavy load and the rotational speed of the rotor 3 increases. The electric machine 1 must then dissipate more heat. Thanks to the high air density at this altitude near the ground, the fins 28, 29 deform and tilt relative to each other, favoring cooling by convection rather than by radiation. The fins 28, 29 then return to their initial position and They become parallel to each other again at higher altitudes due to lower air density, maximizing radiative cooling. This cooling method is used for most of the aircraft's flight.

[0079] This solution makes it possible to improve by 75% the cooling of the annular volume 4 between the stator 2 and the rotor 3 of an electric machine 1 in motion both at low altitude and at high altitude where the air is not very dense.

[0080] Also, when the rotational speed of the rotor 3 is low, at low altitude, the blades 28, 29 are not very inclined relative to each other due to this low speed, the cooling by radiation can then represent up to 35% of the performance in heat dissipation.

[0081] In the embodiment of Figures 1 and 2, the rotor 3 of the electric machine 1 includes a ventilation device 5 movable in rotation relative to the stator 2, positioned at the first end 8a of the electric machine 1 and configured to generate at least one flow of fluid, in particular air, in the annular volume 4 from a longitudinal inlet 6a of the annular volume 4 positioned at the first end 8a of the electric machine 1 to a longitudinal outlet 6b of the annular volume 4 positioned at the second end 8b of the electric machine 1.

[0082] The ventilation device 5 is optional and primarily improves thermal efficiency by convection at low altitudes. At high altitudes, heat dissipation is mainly achieved by radiation through the first and second fins 28, 29.

[0083] The rotation of the rotor 3 causes the fluid to rotate around the axis of rotation X, within the annular volume 4. The fluid flow is represented by arrows in [Fig. 2]. The ventilation device 5 forces the fluid through the annular volume 4, generating a fluid overpressure at the longitudinal inlet 6a and a fluid underpressure at the longitudinal outlet 6b.

[0084] The ventilation device 5 is positioned between the first bearing 7a and the stator 2. The ventilation device 5 is also positioned between the first bearing 7a and the magnets 15 of the rotor 3. The ventilation device 5 is housed in the first housing 14a.

[0085] The ventilation device 5 forces the fluid into the annular volume 4. The fluid is drawn in from outside the electrical machine 1 and then passes through the first bearing 7a to the inlet 6a. The fluid rotates within the annular volume 4, around the axis of rotation X, and then exits the annular volume 4 through the outlet 6b. Heat exchange, primarily by convection, then occurs between the fluid and the air gap of the electrical machine 1, and in particular with the power modules 20, which are thus efficiently cooled by the circulating fluid. The heated fluid is discharged from the electrical machine 1 through the second bearing 7b.

[0086] The ventilation device 5 produces a greater fluid flow in the annular volume 4, thus improving convection cooling. The fluid flow rate is approximately 0.000143 kg / s, for example, for a given rotational speed of the rotor 3.

[0087] The power modules 20 are positioned at the first end 26 of the coil support 21 and opposite the ventilation device 5. This position allows for more efficient cooling of the power modules 20 which are in contact with the cold fluid coming from outside the electrical machine 1.

[0088] The second rows 31 of second fins 29 positioned on the inner face 46 of each power module 20 allow the power modules 20 to be cooled further at high and low altitude.

[0089] Each power module 20 is aligned with one of the teeth 17 of the cylinder head 36 along the direction of the axis of rotation X.

[0090] The ventilation device 5 is fixed around the shaft 9, allowing its rotation around the axis of rotation X and relative to the stator 2.

[0091] The ventilation device 5 comprises a propeller 10 having a ring 11 fixed to the shaft 9 and a plurality of blades 12 extending from the ring 11. The ring 11 is press-fitted onto the shaft 9. The blades 12 are parallelepiped in shape and flat. The blades 12 are positioned opposite an axial end of the magnets 15 and opposite the longitudinal inlet 6a of the annular volume 4.

[0092] As illustrated in Figures 2 and 3, the coil support 21 comprises at least one main channel 23 extending longitudinally in the coil support 21 from an inlet 24 of the main channel 23 positioned at the first end 26 of the coil support 21 to an outlet 25 of the main channel 23 opening at a second end 27 of the coil support 21, opposite the first end 26. The inlet 24 is in fluidic communication with the annular volume 4. The main channel 23 extends between two teeth 17.

[0093] In this example, the main channel 23 has an oblong cross-section. The cross-section of the main channel 23 could be different, such as circular, for example.

[0094] The main channel 23 has a curved shape so that it can extend from the inlet 24, which is in fluidic communication with the annular volume 4, to the outlet 25 of the main channel 23, which is positioned on the side of a radially internal face 35 of the stator 2, opposite the annular volume 4. A portion of the main channel 23 runs along the radially internal face 35 as it approaches the outlet 25. The main channel 23 extends globally along the direction of the axis of rotation X.

[0095] One or more secondary channels 41 extend from the main channel 23 to the second end 27 of the coil support 21. The secondary channels 41 open through an axial face 42 of the stator 2.

[0096] In the example, the secondary channels 41 are straight and extend along the direction of the axis of rotation X. The secondary channels 41 can also be curved. In the example, three secondary channels 41 are connected to the main channel 23. The length of the secondary channels 41 decreases as they approach the radially inner face 35 of the stator 2. The secondary channels 41 have an oblong cross-section, for example.

[0097] The main channel 23 and the secondary channels 41 are positioned between two power sets 18, or in other words, between two teeth 17. Each zone between two power sets 18 comprises a main channel 23 and secondary channels 4L

[0098] Thus, a first portion of the fluid circulates in the annular volume 4 and a second portion of the fluid circulates in the main channel 23 and the secondary channels 41, helping to reduce the pressure induced by the small spacing in the annular volume 4 and improving the flow rate. The coils 19 and the power modules 20 are thus cooled more efficiently by convection. The fluid flow rate decreases from approximately 0.000143 kg / s for an electric machine 1 without channels 23, 41 to approximately 0.000216 kg / s for an electric machine 1 with channels 23, 41, for the same rotor speed 3.

[0099] Alternatively, the rotor 3 of the electric machine 1 does not include a ventilation device 5.

[0100] According to another variant (not shown), the electrical machine 1 comprises a first ventilation device, as described above, positioned in the first housing 14a, downstream of the annular volume 4, and a second ventilation device positioned in the second housing 14b, upstream of the annular volume 4.

[0101] The first ventilation device is configured to force a flow of fluid, from outside the electrical machine 1, to circulate in the annular volume 4. The second ventilation device is configured to extract the fluid from the annular volume 4 to the outside of the electrical machine 1. The airflow is then greater, improving the cooling of the electronic modules.

[0102] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than a restrictive sense.

Claims

Demands

1. An electrical machine (1) comprising a stator (2) and a rotor (3) having an axis of rotation (X), one of the stator (2) or of the rotor (3) coming around the other of the stator (2) or of the rotor (3) such that an annular volume (4) is arranged between the stator (2) and the rotor (3), the stator (2) having a yoke (36) having a plurality of teeth (17) extending radially in the annular volume (4), a plurality of power assemblies (18) each having a coil (19) wound around one of the teeth (17) and a coil support (21) supporting the power assemblies (18), each power assembly (18) having a power module (20) positioned on an inner face (22) of the stator (2), inside the annular volume (4), and configured to supply the coil (19) with current,in which the rotor (3) comprises at least one first blade (28) extending within the annular volume (4) from a first face (32) of the rotor (3) towards the stator (2) along a first radial axis (L1), the stator (2) comprising at least one second blade (29) extending within the annular volume (4) from a second face (22) of the stator (2) towards the rotor (3) along a second radial axis (L2), the first and second blades (28, 29) being rotatable about their respective radial axes (L1, L2) between an inclined position in which the first and second blades (28, 29) form an angle with each other and a non-inclined position in which the first and second blades (28, 29) are parallel, the inclination between the first and second blades (28, 29) increasing with air density when the rotor (3) is in motion.

2. Electric machine (1) according to claim 1, wherein the first and second fins (28, 29) each comprise a central portion (47) positioned between two lateral portions (48), the two lateral portions (48) being made of a shape memory material.

3. Electric machine (1) according to claim 2, wherein the two lateral portions (48) are made of nickel-titanium.

4. Electric machine (1) any one of claims 1 to 3, wherein the rotor (3) comprises at least a first row (30) formed of several first fins (28), the stator (2) comprising at least a second row (31) formed of several second fins (29).

5. Electric machine (1) according to claim 4, wherein the teeth (17) comprise a radially internal face (45) having at least a second row (31) of second fins (29).

6. Electric machine (1) according to any one of claims 4 or 5, wherein each power module (20) comprises a radially internal face (46) having at least a second row (31) of second fins (29).

7. Electric machine (1) according to any one of claims 1 to 6, wherein the rotor (3) comprises a ventilation device (5) movable in rotation relative to the stator (2), positioned at a first end (8a) of the electric machine (1) and configured to generate a fluid flow in the annular volume (4) from a longitudinal inlet (6a) of the annular volume (4) positioned at the first end (8a) of the electric machine (1) to a longitudinal outlet (6b) of the annular volume (4) positioned at a second end (8b) of the electric machine (1), opposite the first end (8a).

8. Electrical machine (1) according to claim 7, wherein the coil support (21) comprises at least one main channel (23) extending longitudinally in the coil support (21) from an inlet (24) of the main channel (23) positioned at a first end (26) of the coil support (21) to an outlet (25) of the main channel (23) opening at a second end (27) of the coil support (21), opposite the first end (26), the inlet (24) being in fluidic communication with the annular volume (4).

9. Aircraft (1) comprising an electric machine (1) according to any one of claims 1 to 8.

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