Electric motor pod for a vertical take-off and landing aircraft and aircraft comprising such a pod

Abstract

The invention relates to a motor pod (1) for a vertical take-off and landing aircraft (VTOL), comprising: a fairing (10) in which an electric motor (20) is housed, the electric motor being equipped with at least one propeller (22) extending outwardly from the top surface (10b) of the fairing, and a cooling device designed to cool the electric motor when the aircraft is in the take-off, cruising and landing phases, and comprising a reversible coolant fluid supply and discharge manifold (30) designed alternately to: - in the cruising phase, receive a cold fluid flow (F3) generated by the movement of the aircraft and convey the fluid flow through the electric motor (20) towards an outlet located opposite the propeller (22), and - in the take-off or landing phase, receive a hot fluid flow (F2) transmitted by the propeller (22) and having passed through the electric motor (20).

Description

Technical Field

[0001] The invention relates to an electric motor pod for a vertical take-off and landing vehicle (VTOL). The invention also relates to a VTOL equipped with such a pod.

[0002] The invention has application in the field of aeronautics, and in particular in the field of VTOL electric motors. Background Art

[0003] Aviation manufacturers seek to develop vertical take-off and landing vehicles (VTOL) that can get rid of the runways usually required for the take-off and landing of conventional aircraft. There are several types of VTOLs, listed according to the motors used. Some VTOLs (hereinafter referred to as aircraft) are equipped with several lifting motors positioned along the vertical axis to ensure the take-off and landing of the aircraft, and pitch motors conventionally positioned along the horizontal axis to ensure the flight of the aircraft in cruise mode.

[0004] The pitch motors of these types of aircraft are usually mounted on beams attached to the fuselage of the aircraft or under the wings of the aircraft in such a way that their axis of rotation is parallel to the fuselage of the aircraft.

[0005] The lift motors, which are usually more numerous than the pitch motors, because more power is needed when ascending than when cruising, are usually mounted on beams attached to the fuselage of the aircraft or on the wings of the aircraft, usually downstream of the pitch motors or conversely upstream of the pitch motors. Each lift motor is an electric motor comprising a rotation axis substantially perpendicular to the plane of the wing and extended by a propeller having several blades. The lift motors must be cooled during the entire duration of the flight, during the ascending phases (take-off and landing) and during the cruising phase. In fact, although during the cruising phase the propellers do not rotate, even the lift motors must be cooled so that the heat caused by take-off is already dissipated when landing.

[0006] More precisely, during the lift phase (i.e. take-off and landing), the propellers rotate and the aircraft is lifted, which generates a vertical air flow that enters the lift motor through its top face 26 facing the propeller. The air passes through the motor and cools it via an exchange surface of the cooling fin type mounted on the motor. During the cruise phase, the aircraft is propelled by the pitch motor in a substantially horizontal direction. The air flow generated by the movement of the aircraft is then horizontal. When the propellers of the lift motors are stopped, the air flow generated by the movement of the aircraft sweeps over the outer surface of the lift motors without penetrating the inside of said motors and approaching the exchange surface.

[0007] At present, in order to allow the air generated by the movement of the aircraft to cool the lifting motors slightly during the cruise phase, aircraft manufacturers choose to leave said lifting motors outside the aircraft structure and therefore not take them into account. However, although the absence of fairings allows the air flow to cool the lifting motors by contacting with the external surface of the lifting motors, the absence of fairings also has the effect of generating aerodynamic losses. In fact, as is known in the field of aeronautics, any component or part of a component that does not meet the aerodynamic profile generates aerodynamic drag. This aerodynamic drag is more significant when the component or part of the component is positioned perpendicular to the plane of the aircraft. The aerodynamic drag generated by each of the lifting motors therefore has to generate an excessive consumption of the power required for the flight of the aircraft, which excessive consumption of power, in addition to being expensive, has a direct impact on the autonomy of the motor when it is an electric motor.

[0008] Other VTOLs are equipped with so-called "steerable" motors instead of lift motors. These steerable motors have the advantage of being able to pivot on themselves, in such a way that their axis of rotation can be switched from a substantially vertical position during the lift phase to a substantially horizontal position during the cruise phase. Thus, the axes of these steerable motors are always in the air flow generated by the movement of the aircraft, regardless of the flight phase. Thus, the steerable motors can be properly cooled during the lift phase as well as during the cruise phase. However, these steerable motors are more difficult to implement than lift motors and require a relatively complex control system, which therefore has a higher manufacturing cost.

[0009] There is therefore a need for a fairing (or protective cover) for a lifting motor that makes it possible to limit the aerodynamic losses generated by said motor, while still making it possible to cool said motor during the lifting phase and during the cruising phase. Summary of the invention

[0010] In order to cope with the above-mentioned problems of aerodynamic losses generated by the lifting motors during the ascent and cruise phases and of cooling these lifting motors, the Applicant proposes a VTOL motor pod, preferably of the aircraft type, provided with a reversible coolant fluid supply and exhaust manifold.

[0011] According to a first aspect, the invention relates to an electric motor pod for a vertical take-off and landing vehicle (VTOL), comprising:

[0012] a spinner in which an electric motor is housed, the electric motor being equipped with at least one propeller extending outwardly from the top surface of the spinner, and

[0013] - a cooling device designed to cool the electric machine when the aircraft is in the take-off, cruising and landing phases and comprising a reversible coolant fluid supply and discharge manifold designed alternately to:

[0014] o receiving a flow of cold fluid generated by the movement of the aircraft during the cruise phase and conveying the flow of fluid through the electric motor towards an outlet located opposite the propeller, and

[0015] oDuring the take-off or landing phase, receiving the hot fluid flow transmitted by the propeller and having passed through the motor.

[0016] The motor pod allows the motor to be integrated into an aerodynamically contoured fairing while still being cooled both in the cruise phase and in the lift phase.

[0017] By definition, a hot fluid flow transported by the propeller is a cooling fluid flow transported by the propeller and heated during its passage through the electrical machine by contact with heat exchange surfaces of said electrical machine.

[0018] Advantageously, the reversible manifold is positioned on the bottom surface of the fairing opposite the top surface.

[0019] In addition to the features that have just been mentioned in the above paragraph, the pod according to one aspect of the invention may have one or more of the following additional features, either alone or in any technically permissible combination:

[0020] - A reversible manifold is an aerodynamically contoured chamber provided with inlet and outlet openings for the fluid and provided with a plurality of distribution channels for the fluid.

[0021] - Distribution channels are distributed in the internal structure of the reversible manifold between the inlet and outlet openings and the bottom face of the motor in such a way that the fluid flow is conveyed from the openings to the heat exchange surfaces of the motor or from the bottom face of the motor to the openings of the reversible manifold.

[0022] -The reversible manifold has the shape of a scoop in the fairing.

[0023] - The reversible manifold has the shape of a NACA inlet in the fairing.

[0024] The fairing surrounding the electric motor comprises an aerodynamic shape extending from the top surface to the bottom surface by flaring in such a way as to create a low air pressure between the top and bottom surfaces.

[0025] The top surface of the fairing surrounding the electric motor comprises at least one protrusion generating a Venturi effect.

[0026] The exchange surface of the electric motor extends substantially vertically between the bottom face and the top face of the electric motor.

[0027] - The opening of the reversible manifold is directed towards the front of the fairing.

[0028] Another aspect of the invention relates to a VTOL equipped with such an electric motor pod. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other advantages and features of the invention will emerge when reading the following description shown in the accompanying drawings, in which:

[0030] Figure 1 shows a schematic side view of an embodiment of a motor pod for a VTOL according to the invention during a lifting phase;

[0031] Figure 2 It is shown that during the cruise phase, Figure 1 A schematic side view of an embodiment of a pod;

[0032] Figure 3 A schematic bottom view showing an embodiment of a reversible coolant fluid supply and exhaust manifold of a pod according to the present invention;

[0033] Figure 4 A schematic view showing an embodiment of an opening of a reversible manifold according to the present invention;

[0034] Figure 5 A schematic elevation view showing a cross section of another embodiment of a motor pod for a VTOL according to the present invention;

[0035] Figure 6 A schematic side view of another embodiment of a motor pod for a VTOL during the cruise phase is shown, wherein the opening of the reversible manifold is directed towards the rear of the fairing. DETAILED DESCRIPTION

[0036] An embodiment of a motor pod for VTOL is described in detail below with reference to the accompanying drawings, the motor pod being configured to limit aerodynamic drag and allow cooling of the motor. This embodiment shows the features and advantages of the present invention. However, it should be noted that the present invention is not limited to this embodiment.

[0037] In the drawings, identical elements are marked with identical reference numerals. Due to the readability of the drawings, the size ratios between the illustrated elements are not maintained.

[0038] exist Figure 1 and Figure 2In the figure, an embodiment of a pod for a lifting motor of a VTOL (also called an aircraft) is schematically shown according to a longitudinal section, i.e. along a plane XY, where X is the displacement axis of the aircraft in the cruise phase and Y is the displacement axis of the aircraft in the lift phase. Figure 1 and Figure 2 As shown, the nacelle 1 according to the present invention comprises a fairing 10 into which a lifting motor 20 is inserted.

[0039] The fairing 10 is an aerodynamically contoured fairing adapted to limit the aerodynamic losses due to the presence of the lifting motor. The fairing may have, for example, an elliptical, rectangular or any symmetrical, asymmetrical, convex or biconvex aerodynamic contour shape.

[0040] The lifting motor 20 is integrated into the fairing 10 in such a way that its rotation axis 21 carrying one or more propellers 22 is parallel to the axis Y. The lifting motor of the VTOL is an electric motor comprising a plane substantially perpendicular to the wing of the aircraft and a rotation axis mounted surrounded by a propeller. The propeller 22 extends outside the top surface 10b of the fairing 10 in such a way that the plane of rotation of the propeller blades is substantially parallel to said top surface of the fairing.

[0041] Like any electric motor, the lifting motor 20 includes various internal components of its rotor mounted around a rotating shaft and a stator mounted around the rotor, which assembly can be protected by a housing. The stator and / or the housing may include heat exchange surfaces, such as cooling fins, on the outer surface, which allow the motor to be cooled by heat exchange between a coolant fluid and the exchange surface.

[0042] The lifting motor can be a motor equipped with its electronics (called smart motor). In this case, the electronics also take advantage of the cooling obtained thanks to the device of the invention.

[0043] The coolant fluid may be air or air in combination with another fluid, such as oil. In the remainder of this specification, the invention will be described in the case where the fluid is air, it being understood that the device implemented in the framework of the invention is the same for air alone or for a combination of air and another fluid, the air / fluid exchanger then being arranged inside the fairing 10.

[0044] The nacelle 1 according to the invention comprises a reversible manifold 30 for supply and discharge of cooling air housed in the fairing 10. According to certain embodiments, the reversible manifold 30 extends over at least a portion of the bottom surface 10a of the fairing, which is the surface of the nacelle facing the ground, i.e., the surface opposite to the top surface 10b on which one or more propellers 22 extend. In these embodiments, the opening of the reversible manifold 30 can be conveyed toward the rear of the fairing or toward the front of the fairing. In other embodiments, the reversible manifold 30 extends over at least a portion of the top surface 10b of the fairing, which is the surface of the nacelle on which one or more propellers 22 extend. In these embodiments, the reversible manifold 30 is provided with holes that allow air to pass through during the take-off and landing phases, and these embodiments advantageously produce even less drag than the embodiment of the reversible manifold on the bottom surface.

[0045] The reversible manifold 30 is a chamber formed inside the fairing 10. The chamber comprises an inlet and outlet opening 31 for air, an outer wall 33 and possibly an inner wall 34. When the inner wall 34 is present, it is in contact with the lifting motor 20 and is provided with holes that allow air to pass through. The outer wall 33 extends for a length at least equal to the diameter "d" of the lifting motor 20 and is preferably greater than the diameter d. The outer wall 33 has an aerodynamic profile between the inlet and outlet opening 31 for air and the closed end 35 of the chamber. In some embodiments, the outer wall 33 is formed by the bottom surface 10a of the fairing. In other embodiments, the outer wall 33 is a wall dedicated to the reversible manifold; in this case, the bottom surface 10a of the fairing comprises an orifice facing the lifting motor 20, and the reversible manifold 30 is added to the bottom surface 10a of the fairing, and the reversible manifold 30 is fastened to the bottom surface 10a of the fairing by any fastening means conventionally used in the field of aeronautics.

[0046] according to Figure 1 and Figure 2 In an embodiment, a reversible manifold 30 is mounted below the lifting motor 20 in such a way that its opening 31 is upstream of the air flow generated by the movement of the aircraft, i.e. the opening 31 is directed towards the front of the fairing and the closed end is directed towards the rear of said fairing. The term "front part of the fairing" refers to the end area of ​​the fairing situated upstream of the air flow generated by the movement of the aircraft, i.e. the area closest to the front of the aircraft. Conversely, the term "rear part of the fairing" refers to the end area of ​​the fairing situated downstream of the air flow generated by the movement of the aircraft, i.e. the area closest to the rear of the aircraft.

[0047] The outer wall 33 and / or the inner wall 34 of the reversible manifold 30 include a plurality of air distribution channels 32. These air distribution channels 32 may be grooves dug out of the material forming the inner surface of the walls 33, 34 or formed by adding edges (e.g., by welding, gluing or brazing) on ​​the inner surface of the walls 33, 34. The air distribution channels 32 may also be made in a single piece with the components of the reversible manifold by casting, molding, extrusion, stamping, rolling, additive manufacturing or any other manufacturing method suitable for manufacturing fairings.

[0048] The air distribution channels 32 extend from the air inlet and discharge openings 31 to the lift motor 20 by following a predetermined path designed to direct the air flow from the openings 31 to the lift motor 20 and from the lift motor 20 to the openings 31. In particular, the air distribution channels 32 are distributed over the walls 33, 34 of the reversible manifold in such a way that the air flow is directed from the openings 31 towards the areas where the heat exchange surfaces, in particular the cooling fins, are located, such as, for example, the peripheral areas 23, 23' of the lift motor.

[0049] Figure 3 , an embodiment of a reversible manifold 30 is shown according to a bottom view. In this embodiment, the reversible manifold 30 has the shape of a pointed sphere including an open base forming an opening 31 and a point forming a closed end 35. Air distribution channels 32 are disposed from the opening 31 in the inner cylindrical region of the chamber and to the entrance of the peripheral region 23, 23' containing the heat exchange surface. Note that the reversible manifold 30 can have various shapes as long as these shapes have an aerodynamic profile. In particular, the reversible manifold 30 can have the shape of a spoon or a NACA grip, such as Figure 4 The term "NACA grip" refers to a flush air inlet, a shape originally developed by the National Advisory Committee for Aeronautics that allows air to penetrate into the internal duct with minimal flow rate disturbance. A NACA grip typically comprises a shallow slope with curved walls, which is embedded in the surface exposed to the air (i.e., the fairing). Many shapes of NACA grips can be considered. In an embodiment in which the reversible manifold 30 has the shape of a NACA unit, the air distribution channels 32 can extend from the slope of the NACA grip. The number of air distribution channels 32 and their trajectory depends of course on the size of the lifting motor, but also on the location of the heat exchange surface and the shape of the reversible manifold. The channels can be, for example, 5 in number, 15 mm in height, with a variable spacing that widens every 15 mm, in this way allowing a better distribution of the air flow to the heat exchanger.

[0050] The reversible manifold 30 as has just been described makes it possible, on the one hand, to supply cool air to the lifting motors 20 during the cruise phase, and, on the other hand, to remove hot air from said motors during the ascent phase. During the cruise phase, the reversible manifold 30 collects and drives (or conveys) the air towards the motors to ensure their cooling, and during the ascent phase, it allows the air to escape without causing any aerodynamic disturbance to the aircraft.

[0051] As explained above, the lift phases are the take-off and landing phases of the aircraft. During these lift phases, the lift motors are running and their propellers are rotating. Figure 1 As shown, during the lifting phase (e.g. take-off), the air flow generated by the propeller and by the movement of the aircraft is directed in a substantially vertical direction (i.e. in the Y direction). Therefore, the cooling air flow represented by the solid arrow F1 penetrates into the lifting motor 20 through the top surface 10b of the nacelle 1 and is pushed into the interior of the motor by the rotating propeller 22. The cooling air flow then follows the Figure 1 2 . This air flow passes through the lifting motor 20 by passing over the heat exchange surfaces of said motor, in this way causing the motor to be cooled. The hot air flow (i.e. the air flow heated by contact with the heat exchange surfaces of the motor) escapes from the motor through its bottom face 25 (i.e. the face opposite to the face receiving the propeller 22) and is removed outside the fairing 10 through a reversible manifold 30 and in particular through an air distribution channel 32 which receives the hot air at the motor outlet 20 and directs it towards an opening 31. The removal of the hot air through the air distribution channel 32 and the opening 31 makes it possible not to generate any aerodynamic disturbance and therefore not to interfere with the ascent or descent of the aircraft.

[0052] The heat exchange surfaces may be, for example, cooling fins arranged in the peripheral region 23, 23' of the lifting motor 20. Conventionally, these fins may be arranged horizontally, i.e. substantially perpendicularly to the axis 21 of the lifting motor. According to an alternative embodiment, the cooling fins are arranged substantially vertically, i.e. in a direction substantially parallel to the axis 21 of the lifting motor, or at an angle of less than 45° relative to said axis of the motor. Alternatively, the heat exchange surfaces may be pipes, pins, ductwork or any other type of heat exchanger known in the field of aerodynamics.

[0053] According to some embodiments, the fairing 10 comprises protrusions 11, 12, 13 in the area near the lifting motor suitable for generating a Venturi effect. The first protrusions 11, 12 may be, for example, portions of the top surface 26 having a positive curvature in the vicinity of the air intake in the lifting motor. Figure 5The second projection 13 shown in can be, for example, a lateral portion of a fairing having a rounded and / or flared shape in plane YZ.

[0054] During the lifting phase, the second projection 13 has the effect of accelerating the speed of the air flow at the inlet of the lifting motor 20, which creates a low pressure in the motor, since the pressure P1 at the inlet is greater than the pressure P2 at the outlet of the reversible manifold 30. This low pressure therefore facilitates the air flow through the lifting motor.

[0055] exist Figure 2 During the cruise phase shown in , the aircraft moves in a substantially horizontal direction (X direction) and the propeller 22 of the lifting motor does not rotate. The air flow generated by the movement of the aircraft is directed in a substantially horizontal direction indicated by the solid arrow F3. Thus, the cold air flow is directed in a direction of about 90° from the bottom surface of the lifting motor. This cold air flow then penetrates through the opening 31 into the reversible manifold 30 and is conveyed through the air distribution channel 32 towards the bottom surface 25 of the lifting motor 20, as shown in FIG. Figure 2 This air flow driven by the channel 32 then passes through the lifting motor 20 by passing over the heat exchange surface of the motor, in this way cooling the motor. The hot air flow (i.e., the air flow heated by contact with the heat exchange surface of the motor) escapes from the lifting motor through its top surface 26. When the propeller 22 is not running, the hot air is removed by flowing along the top surface 10b of the fairing. Any aerodynamic disturbance that the air outlet in this area can present is much smaller than the aerodynamic disturbance generated by the propeller 22 and its shaft 21, and therefore does not further interfere with the flight of the aircraft.

[0056] During this cruising phase, the reversible manifold 30 operates like a spoon that captures air and delivers it to the lift motors and in particular to their heat exchange surfaces.

[0057] In the embodiment in which the fairing 10 comprises first protrusions 11, 12 in the region close to the lifting motor, the protrusions produce a Venturi effect. These first protrusions 11, 12 can be distributed, for example, in the following manner:

[0058] a projection 12 on the top surface 10b of the fairing in the area between the front part of the fairing 10 and the lifting motor 20, for example, immediately in front of the front peripheral area 23 of the lifting motor 20, and

[0059] A projection 11 on the top face 10 b of the fairing in the area covering the lifting motor 20 , for example, immediately before the rear peripheral area 23 ′ of the lifting motor 20 .

[0060] These first projections 11, 12 have the effect of accelerating the speed of the air flow at the outlet of the lifting motor 20 (i.e. in the vicinity of the top face 26 of said motor), which creates a low air pressure since the pressure P1 at the outlet of the motor is greater than the pressure P2 at the inlet of the reversible manifold 30. This low air pressure therefore facilitates the air flow through the lifting motor 20.

[0061] Figure 6 A schematic longitudinal cross-sectional view of an embodiment of a pod for a lifting motor of a VTOL according to another embodiment is shown. In this embodiment, the pod 1 is combined with Figure 1 The pod described is identical, except that a reversible manifold 30 is mounted below the lifting motor 20 in such a way that its opening 31 is located downstream of the air flow generated by the movement of the aircraft, i.e. the closed end is directed towards the front of the aircraft and the opening 31 is directed towards the rear of said aircraft.

[0062] In this embodiment, the low pressure generated at the outlet of the reversible manifold 30 will draw air, because the pressure P1 at the inlet of the lifting motor 20 is greater than the pressure P2 at the outlet of the reversible manifold 30. In order to increase this low pressure, the top surface 10b of the fairing can include, for example, third protrusions 14. These third protrusions 14 can be located on the top surface 10b of the fairing, in the area covering the lifting motor 20, for example, immediately behind the front peripheral area 23 of the lifting motor 20. Such protrusions 14 facilitate the air flow into the lifting motor 20 via a suitable shape.

[0063] Regardless of the embodiment of the pod of the lifting motor described above, additional air circulation equipment can be installed in the pod to increase the air flow or the speed of the air flow passing through the lifting motor. The circulation equipment can be, for example, a fan, a compressor or any other equipment that allows the air inside the pod to circulate. The circulation equipment can be an independent device or a device that is controlled to rotate by the lifting motor or by the shaft of the propeller.

[0064] Although the present invention has been described through a number of embodiments, alternatives and implementations, the pod of the VTOL motor according to the present invention includes various alternatives, modifications and improvements, which will be obvious to those skilled in the art and should be understood to be part of the scope of the present invention.

Claims

1. A motor pod (1) for a vertical take-off and landing aircraft (VTOL), comprising: a fairing (10) in which an electric motor (20) is housed, said electric motor being equipped with at least one propeller (22) extending outwards from the top surface (10b) of the fairing, and - a cooling device designed to cool the electric motor when the aircraft is in the take-off, cruising and landing phases, and comprising a reversible coolant fluid supply and discharge manifold (30) designed alternately to: o receiving, during the cruise phase, a flow of cold fluid (F3) generated by the movement of the aircraft and conveying it through the electric motor (20) towards an outlet located opposite the propeller (22), and o During the take-off or landing phase, a cooling fluid flow (F2) transmitted by the propeller (22) and having passed through the electric motor (20) is received, the cooling fluid flow being heated by contact with the heat exchange surface of said electric motor.

2. The electric motor pod according to claim 1, characterized in that: The reversible manifold is positioned on the bottom surface (10a) of the fairing opposite the top surface (10b).

3. The motor pod according to claim 1, characterized in that: The reversible manifold (30) is an aerodynamically contoured chamber provided with fluid inlet and outlet openings (31) and provided with a plurality of fluid distribution channels (32).

4. The motor pod according to claim 3, characterized in that: Distribution channels (32) are distributed in the internal structure of the reversible manifold (30) between the inlet and outlet openings (31) and the bottom face (25) of the motor in such a way that the fluid flow is conveyed from the openings to the heat exchange surfaces of the motor or from the bottom face (25) of the motor to the openings (31) of the reversible manifold (30).

5. The motor pod according to claim 1, characterized in that: The reversible manifold (30) has the shape of a scoop in the fairing.

6. The electric motor pod according to claim 1, characterized in that: The reversible manifold (30) has the shape of a NACA grip in the fairing.

7. The electric motor pod according to claim 1, characterized in that: A fairing (10) surrounding the electric motor comprises an aerodynamic shape extending from the top surface (26) to the bottom surface (25) of the electric motor by flaring in such a way that a negative pressure is generated between the top and bottom surfaces of the electric motor.

8. The electric motor pod according to claim 1, characterized in that: The top surface (10b) of the fairing surrounding the electric motor includes at least one protrusion (11, 12) that produces a Venturi effect.

9. The electric motor pod according to any one of claims 4 to 8, characterized in that: The exchange surface of the motor extends substantially vertically between a bottom surface (25) and a top surface (26) of the motor.

10. The electric motor pod according to any one of claims 4 to 8, characterized in that The opening (31) of the reversible manifold (30) is directed towards the front of the fairing (10).

11. Vertical take-off and landing vehicle (VTOL) comprising at least one electric motor pod (1) according to claim 1.

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