Vehicle wheel comprising a drive device and a braking device

Abstract

A wheel (1) rotatably mounted on an axle and comprising: - a rim (2) connected by a web (3) to a hub (4) pivotably received on the axle, and delimiting with the hub an annular space; - a radial flux electric motor (10) comprising a first stator (11) and a first rotor (12) which are arranged to generate a torque for the rotational driving of the wheel; - a magnetic brake (20) comprising a second stator (21) and a second rotor (22) which are arranged to generate a torque for the braking of the wheel, the electric motor and the magnetic brake extending one inside the other inside the annular space, of the first rotor and the second rotor one being adjacent to the rim and of the the first rotor and the second rotor the other being adjacent to the hub, the first stator and the second stator extending between the first rotor and the second rotor.

Description

[0001] VEHICLE WHEEL COMPRISING A DRIVE DEVICE AND A BRAKING DEVICE

[0002] The present invention relates to the braking and ground movement of a vehicle and, more particularly, to a wheel comprising a braking device and a drive device.

[0003] BACKGROUND OF THE INVENTION

[0004] In the field of aviation, it is now planned to equip aircraft wheels with rotary drive members to allow aircraft to move on the ground without using their powertrains. It is also known to equip aircraft wheels with a brake intended to selectively slow down and stop said aircraft when they are moving on the ground. The brake is generally friction so that it requires the replacement of wear elements whose friction, during braking, generates particularly polluting dust particles.

[0005] An aircraft wheel typically comprises a rim connected by a web to a hub which is mounted for rotation on an axle carried by a lower end of a landing gear.

[0006] However, in the case of electric vertical take-off and landing (eVTOL) aircraft, the wheels are traditionally small (between 6 and 10 inches) so it is very difficult to integrate both a drive unit and a brake.

[0007] Furthermore, the landing gear of eADAVs is generally fixed, i.e. not movable between a retracted and a deployed position as is the case for larger aircraft. Increasing the size of the wheels to incorporate a drive unit and a brake would therefore tend to increase the drag forces exerted on the landing gear during flight, and therefore reduce the flight autonomy of the eADAV.

[0008] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those currently in operation, requiring the implementation of technological solutions to make them compliant with current regulations. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change.

[0009] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. All stakeholders in the sector are constantly working to improve energy efficiency. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental impacts with the aim of improving the energy efficiency of air transport.

[0010] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0011] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

[0012] SUBJECT OF THE INVENTION

[0013] The aim of the invention is to propose a wheel integrating a drive device and a braking device making it possible to at least partially overcome the aforementioned drawbacks.

[0014] SUMMARY OF THE INVENTION

[0015] For this purpose, according to the invention, a vehicle wheel is provided which is rotatably mounted on an axle. The wheel comprises:

[0016] - an annular rim connected by a web to a hub pivotally received on the axle, the rim delimiting with the hub an annular space closed by the web;

[0017] - a radial flux electric motor comprising a first stator and a first rotor arranged coaxially with the wheel to produce between them a first magnetic flux capable of generating a torque for driving the wheel in rotation;

[0018] - a magnetic brake extending inside the annular space and comprising a second stator and a second rotor arranged coaxially with the wheel to produce between them a second magnetic flux capable of generating eddy currents generating a braking torque of the wheel.

[0019] According to the invention, the electric motor and the magnetic brake extend into each other within the annular space, one of the first rotor and the second rotor being adjacent to the rim and the other of the first rotor and the second rotor being adjacent to the hub, the first stator and the second stator extending between the first rotor and the second rotor.

[0020] The electric motor and the magnetic brake are thus engaged with each other and occupy a relatively small volume. This results in a radial superposition of the electric motor and the magnetic brake which allows their integration inside the wheel without significantly increasing the drag forces which oppose the movement of said wheel.

[0021] According to a particular characteristic of the invention, the first stator and the second stator are radially opposite each other.

[0022] In particular, the first stator extends inside the second stator.

[0023] In particular, the magnetic brake is radial flux.

[0024] In particular, the first stator and the second stator are fixedly mounted on either side of a tubular support extending coaxially around the hub, the support being immobile with respect to the axle.

[0025] In particular, the support is made of or coated with an iron-based material in order to limit or even eliminate crosstalk between the electromagnetic fields generated by the electric motor and those generated by the magnetic brake.

[0026] According to another particular characteristic, the first rotor comprises permanent magnets capable of interacting with windings equipping the first stator.

[0027] According to another particular characteristic, the second stator comprises electromagnets capable of generating eddy currents in the second rotor made of electrically conductive material.

[0028] In particular, the second rotor is formed by the rim made of electrically conductive material. In particular, the second rotor is formed by a local coating arranged on an internal periphery of said rim, the coating being made of electrically conductive material.

[0029] The invention also relates to an aircraft landing gear comprising at least one such wheel.

[0030] The invention further relates to an aircraft comprising at least one such landing gear.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The invention will be better understood in the light of the following description, which is purely illustrative and non-limiting, and must be read in conjunction with the appended drawings, among which: [Fig.l] Figure 1 is a simplified representation of an aircraft comprising main landing gears each provided with a wheel according to the invention;

[0033] [Fig.2] Figure 2 is an axial sectional view of one of the wheels of the aircraft illustrated in Figure 1, according to a particular embodiment of the invention.

[0034] DETAILED DESCRIPTION OF THE INVENTION

[0035] With reference to Figure 1, the invention is described in application to an electric vertical takeoff and landing (eVTOL) aircraft A. The aircraft A comprises two main landing gears P, each comprising a leg J ​​having an upper end fixed to a structure S of the aircraft and, opposite, a lower end carrying a wheel 1 rotating about an axis X on an axle E. The landing gears P are fixed here, but the invention is applicable to retractable type landing gears, or even to another type of aircraft or vehicle such as a land vehicle.

[0036] The wheel 1 comprises, as illustrated in Figure 2, an annular rim 2 connected by a web 3 to a hub 4 pivotally received on the axle E by means of bearings 5, 6. The rim 2 extends coaxially around the hub 4 and delimits with said hub 4 an annular space having one end at least partially closed by the web 3 and, opposite, an open end.

[0037] Wheel 1 is said to be “motorized”, that is to say equipped with a drive device intended to move aircraft A without using its power units when it is on the ground.

[0038] The drive device comprises a radial flux electric motor 10 comprising, in a manner known per se, a first fixed element or stator 11, and a first rotating element or rotor 12. The stator 11 and the rotor 12 each have a central axis coincident with the axis X of rotation of the wheel 1, the rotor 12 extending inside the stator 11 and radially opposite said stator 11.

[0039] The stator 11 here has the shape of a crown fixedly mounted on an internal periphery of a tubular support 30 extending coaxially around the hub 4. The support 30 forms with the axle E an annular groove having a bottom 31 connecting one end of the support 30 to the axle E, so that the stator 11 is immobile with respect to said axle E. The crown forming the stator 11 here comprises a pack of sheets forming a plurality of teeth which extend radially around the axis X and on which windings (not shown) are wound.

[0040] The rotor 12 here has the shape of a crown fixedly mounted on an external periphery of the hub 4 extending radially opposite the stator 11, so that said rotor 12 is immobile with respect to the wheel 1. The crown forming the rotor 12 comprises a series of permanent magnets (not shown) capable of interacting with the windings equipping the stator 11 to produce a first magnetic flux driving the rotor 12, and therefore the wheel 1, in rotation around the axis X. The permanent magnets are for example arranged so as to have an alternation of north poles and south poles, or even to form a Halbach network.

[0041] It is understood that when the windings equipping the stator 11 are crossed by an electric current, they generate magnetic fields sufficient to generate a driving torque in rotation of the hub 4, and therefore of the wheel 1, by interacting with the series of permanent magnets equipping the rotor 12.

[0042] Wheel 1 is also called “braked”, that is to say equipped with a braking device intended to selectively slow down aircraft A when it is on the ground.

[0043] The braking device comprises a radial flux magnetic brake 20 and comprises, in a manner known per se, a second fixed element or stator 21, and a second rotating element or rotor 22. The stator 21 and the rotor 22 each have a central axis coincident with the axis X of rotation of the wheel 1, the stator 21 extending inside the rotor 22 and radially opposite said rotor 22.

[0044] The stator 21 here has the form of a crown fixedly mounted on an external periphery of the support 30 around which the rim 2 extends, so that the stator 21 is immobile with respect to the axle E. The crown forming the stator 21 comprises a series of electromagnets (not shown) defining a main surface 21.1 of the stator 21.

[0045] The rotor 22 is here formed by the rim 2 made here in an electrically conductive material (for example aluminum, steel, etc.), so that said rotor 22 is immobile with respect to the wheel 1. The rim 2 comprises an internal periphery defining a main surface 22.1 of the rotor 22 which is separated from the main surface 21.1 of the stator 21 by a predetermined air gap e. The electromagnets of the stator 21 are arranged so as to produce a second magnetic flux generating eddy currents in the rim 2 when said electromagnets are crossed by an electric current and the wheel 1 rotates around its axis X of rotation. The electromagnets are preferably arranged to form a Halbach network so as to maximize the part of the second magnetic flux seen by the rim 2 but also to limit the part of the second magnetic flux sent to the electric motor 10.

[0046] It is also understood that when the electromagnets equipping the stator 21 are crossed by an electric current, they generate in the rotor 22 eddy currents sufficient to generate a braking torque on said rotor 22, and therefore the wheel 1.

[0047] The electric motor 10 and the magnetic brake 20 are controlled independently of each other so that it is possible to use only the series of magnets of the electric motor 10 for driving and the electromagnets of the magnetic brake 20 for braking.

[0048] It will be noted that the support 30 is composed of or coated with an iron-based material in order to limit or even eliminate crosstalk between the electromagnetic fields generated by the electric motor 10 and those generated by the magnetic brake 20.

[0049] It will also be noted that the electric motor 10 and the magnetic brake 20 extend entirely within the annular space defined by the wheel 1, so that the drag forces exerted on the undercarriage P are limited, and this is all the more so since said undercarriage P is not retractable here. Such an arrangement of the electric motor 10 and the magnetic brake 20 thus limits the aerodynamic impact of the undercarriage P.

[0050] It will also be noted that such an arrangement of the electric motor 10 and the magnetic brake 20 makes it possible to simplify the integration of a drive device and a braking device while maintaining adequate performance.

[0051] It should also be noted that by using the rim as a heat sink and eddy current conductor, the drive device is particularly compact and lightweight.

[0052] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0053] Wheel 1 may have a different structure than that described. Rim 2 of wheel 1 may, for example, be made of two half-rims, be made from a single piece, be made in a foundry or by additive manufacturing, etc.

[0054] Although the permanent magnets equipping the rotor 12 of the electric motor 10 rest here directly on the hub 4, they can also rest on a structure fixed to said hub 4.

[0055] Materials other than those indicated may be used.

[0056] Although the rim 2 here forms the rotor 22 of the magnetic brake 20, it can also have its internal periphery provided with a local coating capable of forming said rotor 22 (for example made of copper, aluminum, silver, nickel, etc.). The rim 2 can then be made of a material different from that of the coating.

[0057] The arrangement of the electric motor 10 and the magnetic brake 20 can be reversed. In other words, the stator 11 and the rotor 12 of the electric motor 10 can respectively take the place of the stator 21 and the rotor 22 of the magnetic brake 20, and vice versa. Where appropriate, the stator 11 and the rotor 12 of the electric motor 10 are respectively fixedly mounted on the external periphery of the support 30 and the internal periphery of the rim 2, and the stator 21 of the magnetic brake 20 is fixedly mounted on the internal periphery of the support 30, the rotor 22 being formed by the hub 4 or by a local coating equipping the internal periphery of said hub 4.

[0058] The permanent magnets may be carried by the stator 11 instead of the rotor 12. The electromagnets may be carried by the rotor 22 instead of the stator 21.

[0059] Although the rotor 12 of the electric motor 10 here comprises permanent magnets to, for example, form a synchronous motor, it can also comprise electromagnets to, for example, form an asynchronous motor.

[0060] Although the stator 21 of the magnetic brake 20 here comprises electromagnets, it may also comprise permanent magnets. In particular, the electromagnets and the permanent magnets may be arranged alternately so as to form a Halbach network: the electromagnets have alternating north poles and south poles, and the permanent magnets, of smaller sizes, have alternating east poles and west poles so as not to brake the wheel 1 significantly on their own.

[0061] The Halbach pattern arrangement of the magnets of the electric motor 10 and the electromagnets of the magnetic brake 20 is advantageous but not obligatory.

[0062] The drive device may further comprise a reducer to increase the drive torque delivered to the wheel 1 by the electric motor 10. The reducer may be of any type: planetary reducer, strain wave reducer, cycloidal reducer, etc.

[0063] Although the rotor 22 of the magnetic brake 20 is here formed by the rim 2 or by a local coating arranged on the internal periphery of said rim 2, it can also be formed by any element attached directly or indirectly to the rim 2. The arrangement and the number of bearings 5, 6 making it possible to ensure the rotation of the wheel 1 around the axis X can be different from those described and illustrated.

[0064] At least one bearing can be arranged between the rim 2 and the support 30 so as to guarantee a constant air gap e between the main surface 21.1 of the stator 21 and the main surface 22.1 of the rotor 22 so that the braking torque exerted by the magnetic brake 20 is constant (the braking torque being, in a manner known per se, a function of the air gap e).

[0065] The number of stators (11, 21) and / or rotors (12, 22) may be different from those described.

[0066] The invention is applicable to other types of eddy current brake, in particular axial flow or combining axial flow with radial flow.

[0067] The invention can be used on any type of vehicle, air, land or amphibious.

[0068] The invention can be used for applications other than a vehicle and for example for any industrial or personal equipment requiring braking.

Claims

CLAIMS 1. Vehicle wheel (1), rotatably mounted on an axle (E), comprising: - an annular rim (2) connected by a web (3) to a hub (4) pivotally received on the axle, the rim delimiting with the hub an annular space closed by the web; - a radial flux electric motor (10) comprising a first stator (11) and a first rotor (12) arranged coaxially with the wheel to produce between them a first magnetic flux capable of generating a torque for driving the wheel in rotation; - a magnetic brake (20) comprising a second stator (21) and a second rotor (22) arranged coaxially with the wheel to produce between them a second magnetic flux capable of generating eddy currents generating a braking torque of the wheel; characterized in that the electric motor and the magnetic brake extend one inside the other inside the annular space, one of the first rotor and the second rotor being adjacent to the rim and the other of the first rotor and the second rotor being adjacent to the hub, the first stator and the second stator extending between the first rotor and the second rotor.

2. Wheel (1) according to claim 1, in which the first stator (11) and the second stator (21) are radially opposite each other.

3. Wheel (1) according to claim 2, wherein the first stator (11) extends inside the second stator (21).

4. Wheel (1) according to any one of the preceding claims, in which the magnetic brake (20) is radial flux.

5. Wheel (1) according to claim 4, in which the first stator (11) and the second stator (21) are mounted fixed on either side of a tubular support (30) extending coaxially around the hub (4), the support being immobile with respect to the axle (E).

6. Wheel (1) according to claim 5, in which the support (30) is composed of or coated with an iron-based material in order to limit or even eliminate crosstalk between the electromagnetic fields generated by the electric motor (10) and those generated by the magnetic brake (20).

7. Wheel (1) according to any one of the preceding claims, in which the first rotor (12) comprises permanent magnets capable of interacting with windings equipping the first stator (11).

8. Wheel (1) according to any one of the preceding claims, in which the second stator (21) comprises electromagnets capable of generating eddy currents in the second rotor (22) made of electrically conductive material.

9. Wheel (1) according to claim 8, wherein the second rotor (22) is formed by the rim (2) made of electrically conductive material.

10. Wheel (1) according to claim 8, in which the second rotor (22) is formed by a local coating arranged on an internal periphery of said rim (2), the coating being made of electrically conductive material.

11. Landing gear (P) of an aircraft (A) comprising at least one wheel (1) according to any one of the preceding claims.

12. Aircraft (A) comprising at least one landing gear (P) according to claim 11.

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