Magnetic coupling vehicle wheel rotation drive device

Abstract

A drive device (100, 100') for a wheel (10) mounted for rotation on an axle (5), comprising: a motor (110) intended to be fixed relative to the axle; a guide rotor (120, 120') driven in rotation by the motor; and a follower rotor (140, 140', 140'') intended to be rotationally fixed to the wheel, the guide rotor and the follower rotor being arranged to form a magnetic coupling. (Figure from the abbreviation: Fig. 2A)

Description

Title of the invention: Magnetic coupling device for rotating a vehicle wheel

[0001] The present invention relates to the ground movement of a vehicle, and in particular to a magnetically coupled wheel drive device. The invention also relates to a wheel, an aircraft landing gear, and an aircraft equipped with such a drive device.

[0002] BACKGROUND OF THE INVENTION

[0003] In the field of aviation, it is now known to equip aircraft with wheel rotation drive devices to allow the aircraft to move on the ground without using its power-driven propulsion systems.

[0004] Indeed, climate change is a major concern for many legislative and regulatory bodies worldwide. 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 types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively contributing to the fight against climate change for several years now. Technological research efforts have already led to very significant improvements in the environmental performance of aircraft.The Applicant takes into consideration the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0005] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0006] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0007] Thus, it is known to equip aircraft wheels with a drive unit comprising an electric motor which is mechanically connected to the wheel via a gear train to transmit a rotational torque to said wheel.

[0008] However, the wheel and the axle on which it is mounted undergo significant deflections during the rolling phases, which can damage the gear train and / or the motor.

[0009] Moreover, the sudden acceleration of the wheel during landing also tends to damage the gear train and the engine. To overcome this problem, the integration of a clutch device could be considered. However, integrating such a clutch device would increase the weight of the lander and could prove very difficult in an environment where space is already very limited.

[0010] SUBJECT OF THE INVENTION

[0011] The invention therefore aims to provide a device for rotating a vehicle wheel that at least partially overcomes the aforementioned drawbacks. Summary of the invention

[0012] To this end, a drive device for a wheel mounted to rotate on an axle is proposed, comprising: • a motor intended to be fixed relative to the axle; • a guide rotor driven in rotation by the motor; and • a follower rotor intended to be fixed in rotation to the wheel.

[0013] According to the invention, the guide rotor and the follower rotor are arranged to form together a magnetic coupling.

[0014] Such a magnetic coupling thus tolerates a certain parallel and angular misalignment between the guide rotor and the follower rotor. This makes it possible to absorb deflections of the wheel and / or axle without affecting the operation of the drive device or its service life.

[0015] Moreover, such a magnetic coupling has a limit on the transmissible torque between the guide rotor and the follower rotor. This prevents overloads and potential damage to the motor and its mechanical connection to the guide rotor.

[0016] According to a particular feature, one of the guide rotor and the follower rotor is a magnetic rotor comprising a series of magnets regularly distributed around a central axis.

[0017] According to another particular characteristic, the other of the guide rotor and the follower rotor is an inductive rotor or a ferromagnetic rotor.

[0018] According to another particular feature, the guide rotor is driven in rotation by the motor via a reducer.

[0019] According to another particular characteristic, the motor is an electric motor.

[0020] The invention also relates to a vehicle wheel mounted for rotation on an axle and comprising such a drive device, the motor being fixed relative to the axle and the follower rotor being rotationally fixed to the wheel and extending coaxially to said wheel.

[0021] According to a particular feature, the guide rotor and the follower rotor are arranged coaxially with respect to each other.

[0022] According to another particular feature, when viewed along a direction defined by an axis of rotation of the wheel, an annular magnetic surface of one of the guide rotor and the follower rotor covers a unique annular portion of the other of the guide rotor and the follower rotor, the guide rotor and the follower rotor having central axes that are distant from each other.

[0023] The invention also relates to an aircraft landing gear comprising at least one such braked wheel.

[0024] The invention further relates to an aircraft comprising at least one such landing gear. Brief description of the drawings

[0025] The invention will be better understood in the light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying drawings, among which:

[0026] [Fig-1] [Fig.1] is a simplified view of an aircraft including landing gear main ones equipped with motorized wheels;

[0027] [Fig.2A] [Fig.2A] is an axial cross-sectional view of one of the motorized wheels of the aircraft illustrated in [Fig.1], according to a first embodiment of the invention;

[0028] [Fig.2B] [Fig.2B] is an exploded perspective view of the motorized wheel illustrated in [Fig.2A];

[0029] [Fig.2C] [Fig.2C] is an exploded perspective view of part of the drive device of the motorized wheel illustrated in [Fig.2B];

[0030] [Fig.3A] [Fig.3A] is a view identical to [Fig.2A] illustrating a motorized wheel according to a second embodiment of the invention;

[0031] [Fig.3B] [Fig.3B] is an exploded perspective view of the motorized wheel illustrated in [Fig.3A];

[0032] [Fig.4] [Fig.4] is a perspective view of variants of the rotor following the motorized wheels illustrated in [Fig.2A] and [Fig.3A]. DETAILED DESCRIPTION OF THE INVENTION

[0033] With reference to [Fig. 1], the invention is described in application to an aircraft 1 comprising two main landers 2. Each of the main landers 2 comprises a leg 3 having a first end articulated on a structure 4 of aircraft 1 and, opposite, a second end provided with a tubular shaft or axle 5 carrying wheels 10 rotating around an axis Xi0. The main landers 2 are here of the retractable type but the invention is applicable to fixed landers, or even to another type of vehicle such as a land vehicle.

[0034] The following description relates to one of the wheels 10 of the aircraft, the wheels 10 being identical here but also being different.

[0035] With reference to Figures 2A-2C, wheel 10 comprises: • an 11 annular rim on which a tire is mounted (not shown); • a hub 13 received to pivot on the axle 5 by means of bearings 14; and • a veil 12 connecting the rim 11 to the hub 13.

[0036] The rim 11 has free ends, each provided with an annular flange 11.1 extending radially outwards from the wheel 10 to form axial stops preventing the tire from coming off the rim. The bearings 14 are received in bores formed axially on either side of said axle 13.

[0037] The wheel 10 is said to be "motorized", that is to say, equipped with a drive device 100 intended to move the aircraft 1 without using its power-driven propulsion units when it is on the ground.

[0038] According to a first embodiment of the invention, the drive device 100 comprises: • an electric motor 110 which is connected to a control unit (not shown); • an annular guide rotor 120 which is driven in rotation by the motor 110 via a reduction gear 130; and • an annular follower rotor 140 which is rotationally fixed to the wheel 10 to form a magnetic coupling with the guide rotor 120.

[0039] The motor 110 is here radial flux and comprises, in a manner known per se, a casing 111 in which are received a fixed element or stator 112, and a rotating moving element or rotor 113.

[0040] The housing 111, which is generally cylindrical in shape, includes one end, facing the reducer 130, provided with a radial tab 111.1 for fixing the motor 110 to an external flange 5.1 of the axle 5. The tab 111.1 has a hole through which the motor 110 is threaded onto the axle 5, and is fixed to the flange 5.1 of said axle 5 by means of nuts 114. It is understood that the motor 110 is fixed with respect to the axle 5.

[0041] The stator 112 and the rotor 113 have a central axis Xn0 parallel to the axis Xi0 of rotation of the wheel 10, the rotor 113 extending inside the stator 112 and radially opposite said stator 112. The rotor 113 is here tubular in shape and comprises a end defining an outlet port of the motor 110 provided with an internal groove 113.1.

[0042] The reducer 130 comprises an annular housing 131 extending around the axle 5 and in which are housed: • an input tree 132; • a toothed ring 133 cooperating with the input shaft 132; and • the guide rotor 120 fixed in rotation to the toothed ring 133.

[0043] The housing 131 comprises a main body 131.1 defining an annular groove, and a cover 131.2 defining with the main body 131.1 a closed housing volume for the input shaft 132, the toothed ring 133, and the guide rotor 120. The main body 131.1 includes a radially extending base having an internal flange through which the housing 131 is threaded onto the axle 5. The internal flange is fixed to the external flange 5.1 of the axle 5 via the nuts 114. It is understood that, like the motor 110, the housing 131 is fixed with respect to the axle 5.

[0044] The input shaft 132 extends through a hole formed in the bottom of the main body 131.1 of the housing 131 and has a longitudinal axis Xn2, coinciding with the central axis Xn0 of the motor 110, along which it is mounted movably in rotation within the housing 131 via a bearing 134 extending around a central section of said input shaft 132. The input shaft 132 has a first end which extends inside the rotor 113 and which is provided with an external spline 132.1 cooperating with the internal spline 113.1 of said rotor 113, and a second end, opposite to the first end, which extends inside the housing 131 and which is provided with a spur gear 132.2. It is understood that a rotation of the rotor 113 of the motor 110 causes a rotation of the input shaft 132 of the reducer 130.

[0045] The toothed ring 133 extends entirely within the housing 131 and has a central axis Xi33, coinciding with the axis Xi0 of rotation of the wheel 10, along which it is mounted for rotation within the housing 131 via a bearing 135 extending within said toothed ring 133. The toothed ring 133 has external straight teeth cooperating with the teeth of the pinion 132.2. It is understood that a rotation of the input shaft 132 around its longitudinal axis Xn2 causes a rotation of the toothed ring 133 around its central axis Xi33.

[0046] The guide rotor 120 extends entirely within the housing 131 and coaxially with the toothed ring 133. The guide rotor 120 comprises an internal flange provided with axial peripheral notches 120, each receiving a tenon 133.1 extending axially from a radial face of the toothed ring 133 facing the wheel 10 to ensure rotational coupling of said toothed ring 133 with said guide rotor 120 about the axis Xi0 of rotation of the wheel 10. includes that a rotation of the toothed ring 133 around its central axis XB3 causes a rotation of the guide rotor 120 around the axis Xi0 of rotation of the wheel 10. The internal flange of the guide rotor 120 is also fixed to the radial face of the toothed ring 133 via screws 136 extending each between two adjacent notches 120.1, so that said guide rotor 120 is fixed relative to said toothed ring 133.

[0047] The guide rotor 120 also includes a radial face provided with a series of permanent magnets 120.1 defining a main surface of the guide rotor 120, which is flat, extending transversely to the axis Xi0 of rotation of the wheel 10 and which is turned towards the follower rotor 140. The cover 131.2 of the gearbox housing 131 extends radially between the guide rotor 120 and the follower rotor 140 and is made of a non-magnetic and non-conductive material. The magnets 120.1 are regularly distributed around the central axis X^o of the guide rotor 120 so as to emit an axial magnetic flux capable of generating eddy currents in the follower rotor 140 to produce a driving torque of the wheel 10 when said guide rotor 120 pivots around its central axis Xi20 relative to said follower rotor 140. The guide rotor 120 is thus a magnetic rotor.

[0048] The follower rotor 140 is here an inductive rotor in that it is made of an electrically conductive material to interact with the guide rotor 120 by induction. The follower rotor 140 extends coaxially with the wheel 10 and has an inner circumference which includes axial peripheral notches 140.1, each receiving a section of a tenon 13.1 which is fixed to an outer surface of an inner end of the hub 13 of the wheel 10 to ensure rotational coupling of said follower rotor 140 with said wheel 10. It is understood that a rotation of the follower rotor 140 causes a rotation of the wheel 10 about its axis of rotation Xi0. The outer surface of the hub 13 also includes a groove in which a stop ring 15 is received, clamping the follower rotor 140 against a shoulder of the hub 5, so that said follower rotor 140 is fixed relative to the wheel 10.

[0049] The follower rotor 140 extends axially relative to the guide rotor 120 and is separated from said guide rotor 120 by a substantially constant air gap e. This air gap is sufficiently small for the drive torque transmitted to the wheel 10 to be significant, and sufficiently large for the deformation of the wheel 10 and / or the axle 5 not to cause friction between the follower rotor 140 and the cover 131.2 of the gearbox housing 131. The guide rotor 120 and the follower rotor 140 thus form a magnetic coupling which allows, in particular, misalignment of said guide rotor 120 and said follower rotor 140.

[0050] The operation of the drive device 100 will now be detailed.

[0051] While the wheel 10 is stationary, starting the electric motor 110 causes the input shaft 132 to rotate around its central axis Xn2, which in turn causes the toothed ring 133, and therefore the guide rotor 120, to rotate substantially around the axis of rotation of the wheel 10. The guide rotor 120 then has a rotational speed greater than that of the follower rotor 140. The magnetic flux generated between the guide rotor 120 and the follower rotor 140 then produces a driving torque on said follower rotor 140, and therefore on the wheel 10, whose speed tends to increase until it reaches that of the guide rotor 120. It is thus understood that starting the electric motor 110 causes the wheel 10 to rotate and therefore causes the aircraft 1 to move when it is on the ground.

[0052] The drive device 100 can also function as an eddy current brake: when the rotational speed of the guide rotor 120 is less than the rotational speed of the follower rotor 140, the magnetic flux generated between the guide rotor 120 and the follower rotor 140 induces a braking torque on said follower rotor 140 and therefore on the wheel 10, whose speed tends to decrease until it reaches that of the guide rotor 120. Similarly, when the guide rotor 120 and the follower rotor 140 rotate in opposite directions, the magnetic flux generated between the guide rotor 120 and the follower rotor 140 induces a braking torque on said follower rotor 140 and therefore on the wheel 10, whose speed tends to decrease until it is zero before changing sign and reaching that of the guide rotor 120.

[0053] The braking torque transmitted to the wheel can be controlled and maximized by the control unit of the electric motor 110 by controlling the relative speed between the guide rotor 120 and the follower rotor 140. Indeed, the braking torque transmissible to the wheel 10 depends on this relative speed and is maximum for a given relative speed. Thus, the control unit is, for example, configured to control the speed of the motor 110 according to a signal representing the speed of the wheel 10.

[0054] It should be noted that although such a drive device 100 can function as an eddy current brake, it is not suitable for making a parking brake but can for example complement another braking device of the wheel 10, in particular at low speed (for example during taxiing phases).

[0055] It will also be noted that with such a magnetic coupling, a sudden acceleration of the wheel 10 (for example during landing phases) can be partially damped by the magnetic flux generated between the guide rotor 120 and the follower rotor 140, which will reduce the forces applied to the lander 2 and the motor 110.

[0056] With reference to [Fig.4], the inductive follower rotor 140 can be replaced by a magnetic follower rotor 140' or a ferromagnetic follower rotor 140”.

[0057] The follower rotor 140' is, for example, substantially identical to the guide rotor 120 and comprises a radial face provided with a series of magnets defining a main surface of the follower rotor 140', which is flat. This main surface extends transversely to the axis Xi0 of rotation of the wheel 10 and is oriented towards the guide rotor 120 to interact with said guide rotor 120.

[0058] The follower rotor 140” is a rotor made of a ferromagnetic material arranged to interact by reticence and / or hysteresis with the guide rotor 120. The follower rotor 140” includes radial peripheral notches delimiting axial teeth intended to be turned towards the guide rotor 120.

[0059] It should be noted that with the follower rotor 140' or the follower rotor 140”, the drive device 100 can function as a parking brake when the guide rotor 120 has a zero rotational speed. However, depending on the level of torque required to immobilize the wheel 10, another parking brake device may be necessary.

[0060] Whether the inductive follower rotor 140 is replaced by the magnetic follower rotor 140' or by the ferromagnetic follower rotor 140”, the wheel 10 can be driven into rotation before landing in order to reduce the acceleration to which said wheel is subjected when it touches the ground and thus do without a clutch system intended to protect the reducer 130 and the motor 110 from too abrupt an acceleration.

[0061] Figures 3A and 3B illustrate a drive device 100' according to a second embodiment of the invention. The drive device 100' differs from the drive device 100 in that it does not include a reduction gear. The magnetic guide rotor 120 is replaced by a magnetic guide rotor 120' which is rotationally fixed to the rotor of the motor 110.

[0062] The guide rotor 120' extends inside a housing 131' and has a central axis X120' coinciding with the axis Xn0 of rotation of the motor 110. It is understood that the guide rotor 120' extends coaxially with the rotor 113 of the motor 110.

[0063] The housing 131', of overall cylindrical shape, comprises a main body 131.1' delimiting a cylindrical housing, and a cover 131.2' defining with the main body 131.1 a volume for hosting the guide rotor 120'.

[0064] The main body 131.1' comprises a base facing the motor 110 and provided with a radial tab 131.1' for fixing the housing 131' to the external flange 5.1 of the axle 5. The tab 131.1' has a hole through which the housing 131' is threaded onto the axle 5, and is fixed to the flange 5.1 of said axle 5 by means of nuts 114. It is understood that the housing 131' is fixed with respect to the axle 5.

[0065] The guide rotor 120' extends inside the housing 131' and coaxially with the rotor 113 of the motor 110. The guide rotor 120' includes a central drive shaft extending through a hole formed in the bottom of the main body 131.1' of the housing 131'. The drive shaft has a free end which extends inside the rotor 113 and which is provided with an external spline 120.1' cooperating with the internal spline 113.1 of said rotor 113. It is understood that a rotation of the rotor 113 of the motor 110 causes a rotation of the guide rotor 120'.

[0066] The guide rotor 120 also includes a radial face provided with a series of magnets 120.2' defining a main surface of the guide rotor 120', which is flat and extends transversely to the axis Xi0 of rotation of the wheel 10 and is oriented towards the follower rotor 140. The cover 131.2' of the housing 131' extends radially between the guide rotor 120' and the follower rotor 140 and is made of a non-magnetic and non-conductive material. It should be noted that the guide rotor 120' and the follower rotor 140 do not extend coaxially with respect to each other and that, when viewed along a direction defined by the axis Xi0 of rotation of the wheel 10, the main surface of said guide rotor 120' covers a single portion of said follower rotor 140.

[0067] The magnets 120.2' are regularly distributed around the central axis Xi20' of the guide rotor 120' so as to emit an axial magnetic flux capable of generating eddy currents in the follower rotor 140 to produce a driving torque of the wheel 10 when said guide rotor 120' pivots around its central axis X120' relative to said follower rotor 140. The guide rotor 120' is thus a magnetic rotor.

[0068] The operation of the drive device 100' is similar to that of the drive device 100.

[0069] While the wheel 10 is stationary, starting the electric motor 110 causes the guide rotor 120' to rotate substantially around its central axis X120'. The guide rotor 120' then has a rotational speed greater than that of the follower rotor 140. The magnetic flux generated between the guide rotor 120' and the follower rotor 140 then produces a driving torque on said follower rotor 140 and therefore on the wheel 10, whose speed tends to increase until it reaches that of the guide rotor 120'. It is thus understood that starting the electric motor 110 causes the wheel 10 to rotate and therefore causes the aircraft 1 to move when it is on the ground.

[0070] Like the drive device 100', the drive device 100' can also function as an eddy current brake: when the rotational speed of the guide rotor 120' is lower than the rotational speed of the follower rotor 140, the magnetic flux generated between the guide rotor 120' and the follower rotor 140 induces a braking torque on said follower rotor 140 and therefore on the wheel 10, whose speed tends to decrease until it reaches that of the guide rotor 120'. Similarly, when the guide rotor 120' and the follower rotor 140 rotate in opposite directions, the magnetic flux generated between the guide rotor 120' and the follower rotor 140 induces a braking torque on said follower rotor 140 and therefore on the wheel 10, whose speed tends to decrease until it is zero before changing sign and reaching that of the 120' guide rotor.

[0071] The braking torque transmitted to the wheel can be controlled and maximized by the control unit of the electric motor 110 by controlling the relative speed between the guide rotor 120' and the follower rotor 140. Thus, the control unit is arranged for example to control the speed of the motor 110 as a function of a signal representative of the speed of the wheel 10.

[0072] It should be noted that although such a drive device 100' can function as an eddy current brake, it is not suitable for making a parking brake but can for example complement another braking device of the wheel 10, in particular at low speed (for example during taxiing phases).

[0073] It will also be noted that with such a magnetic coupling, a sudden acceleration of the wheel 10 (for example during landing phases) can be partially damped by the magnetic flux generated between the guide rotor 120' and the follower rotor 140, which will reduce the forces applied to the lander 2 and the motor 110.

[0074] As with the drive device 100', the inductive follower rotor 140 can be replaced by a magnetic follower rotor 140' or a ferromagnetic follower rotor 140" ([Fig.4]).

[0075] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0076] The motor 110 can be of any type, such as permanent magnet or induction.

[0077] The follower rotor 140, 140', 140” can be made of material with the rim 11 of the wheel 10.

[0078] Although the guide rotor 120 and the follower rotor 140, 140', 140" are here respectively connected to the motor 110 and the wheel 10, they could, conversely, be connected respectively to the wheel 10 and the motor 110.

[0079] Although the rotational coupling of the follower rotor 140, 140', 140" and the wheel 10 is here ensured by tenons 13.1 received in notches 140.1, any other means could be used to ensure this coupling.

[0080] Like the cover 131.2, 131.2', the main body 131.1, 131.1' of the housing 131 can be made of a non-magnetic and non-conductive material.

[0081] The reducer 130 can be of different types (planetary reducer, deformation wave reducer, worm gear reducer...).

[0082] Although the guide rotor 120' is directly connected to the motor 110, it can also be connected to the motor via a reducer or any other mechanical link.

[0083] The permanent magnets 120.2, 120.2' of the guide rotor 120, 120' can be replaced by electromagnets.

[0084] Although the magnetic coupling generated by the guide rotor 120, 120' and the follower rotor 140, 140', 140" is here axial flux, it can be radial flux.

[0085] The invention is usable on any type of vehicle, aerial or terrestrial or amphibious.

Claims

Demands

1. A drive device (100, 100') for a wheel (10) mounted for rotation on an axle (5), comprising: • a motor (110) intended to be fixed relative to the axle; • a guide rotor (120, 120') driven in rotation by the motor; and • a follower rotor (140, 140', 140”) intended to be rotationally fixed to the wheel, the guide rotor and the follower rotor being arranged to form together a magnetic coupling.

2. A drive device (100, 100') according to claim 1, wherein one of the guide rotor (120, 120') and the follower rotor (140, 140', 140”) is a magnetic rotor comprising a series of magnets regularly distributed around a central axis (Xi20, X^œ)-

3. Drive device (100, 100') according to claim 2, wherein the other of the guide rotor (120, 120') and follower rotor (140, 140', 140”) is an inductive rotor or a ferromagnetic rotor.

4. A drive device (100, 100') according to any one of the preceding claims, wherein the guide rotor (120) is driven in rotation by the motor (110) via a reducer (130).

5. Drive device (100, 100') according to any one of the preceding claims, wherein the motor (110) is an electric motor.

6. Vehicle wheel (10), mounted for rotation on an axle (5), comprising a drive device (100, 100') according to any one of the preceding claims, wherein the motor (110) is fixed relative to the axle and the follower rotor (140, 140', 140") is rotationally fixed to the wheel (10) and extends coaxially with said wheel.

7. Vehicle wheel (10) according to claim 6, wherein the guide rotor (120) and the follower rotor (140, 140', 140”) are arranged coaxially with respect to each other.

8. A vehicle wheel (10) according to claim 6, wherein, when viewed along a direction defined by an axis (Xi0) of rotation of the wheel 10, an annular magnetic surface of one of the guide rotors (120') and the follower rotors (140, 140', 140”) covers a

9.

10. unique annular portion of the other of the guide rotor and the follower rotor, the guide rotor and the follower rotor having central axes (X^o, X^œ, X140) distant from each other. Aircraft landing gear (2), comprising at least one wheel (10) according to any one of the preceding claims. Aircraft (1) comprising at least one landing gear (2) according to claim 9.

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