Taxiing device with mixed friction / magnetic braking, and aircraft equipped with same

Abstract

The invention relates to a taxiing device for a vehicle, comprising a wheel rim pivoting about a shaft and delimiting two recesses (107.1, 107.2), one receiving a friction braking device and the other a magnetic braking device comprising a stator (6) rotatably secured to the shaft, a rotor (5) rotatably secured to the wheel, and a control member (9) of the magnetic braking device extending at least partially into the shaft. The invention also relates to an aircraft comprising such a taxiing device.

Description

[0001] MIXED BRAKING DRIVING DEVICE

[0002] FRICTION / MAGNETIC, AND AIRCRAFT EQUIPPED THEREBY

[0003] The present invention relates to the field of braking vehicle wheels such as aircraft wheels.

[0004] BACKGROUND OF THE INVENTION

[0005] An aircraft wheel generally comprises a rim connected by a web to a hub mounted to rotate on a shaft (axle or rocket) secured to one end of a landing gear.

[0006] Friction braking devices are known comprising a stack of braking discs which is housed in a space extending between the rim and the hub and which comprises an alternation of rotor discs linked in rotation with the wheel and stator discs fixed relative to the wheel support shaft. The braking device also comprises hydraulic or electromechanical actuators mounted on an actuator holder and arranged to apply a controlled braking force to the stack of discs so as to brake the rotation of the wheel.

[0007] It has been proposed, in particular in document FR-A-2953196, to equip such braked wheels with an electromagnetic auxiliary brake ensuring energy dissipation by means other than mechanical friction. However, the free space at the wheel is extremely reduced so that the installation of an auxiliary brake is complicated.

[0008] Eddy current magnetic braking devices (called "Eddy current brake" in English) are also known, used for braking vehicle wheels and more particularly aircraft wheels. For the purposes of the present application, a magnetic braking device is a device dedicated to braking and not a motor which would be used as a generator to perform regenerative braking. Document WO-A-2014 / 029962 describes such a device comprising a stator which is provided with one or more magnets and which is mounted opposite an electrically conductive rotor. Document US-A-20200300310 also describes an eddy current magnetic braking device. Generally speaking, the performance of an eddy current magnetic braking device depends on the power of the magnets used and their dimensions.The braking device is therefore relatively heavy and bulky when the maximum braking power required is high. This is the case, for example, for use on aircraft, even though mass and size are severe constraints for this use.

[0009] SUBJECT OF THE INVENTION

[0010] The invention aims in particular to propose a rolling device having improved braking performance while maintaining a reasonable size.

[0011] SUMMARY OF THE INVENTION

[0012] To this end, the invention provides a rolling device for a vehicle, comprising a leg provided with a shaft and a wheel having a hub mounted to pivot on the shaft. The wheel comprises a rim which is connected to the hub by a web to extend coaxially with the hub. The rim comprises a first annular part which extends projecting from the web and opposite the hub, delimiting therewith a first annular housing having one end closed by the web and one end open towards the leg to receive a friction braking device. The rim comprises a second annular part extending projecting from the web opposite the first annular part, delimiting a second housing having one end closed by the web and one end open opposite.A magnetic braking device is mounted in the second housing, and comprises: - a first element and a second element which has a surface opposite a surface of the first element and is rotatable relative to the first element, one of the first or second element being integral in rotation with the shaft and one of the first or second element being integral in rotation with the wheel.

[0013] - a control member of the magnetic braking device extending at least partially into the shaft.

[0014] This arrangement makes it possible to limit the size of the wheel by integrating at least part of the magnetic braking device. It is therefore possible to have both friction braking and magnetic braking in a wheel whose size remains reasonable for most conceivable applications, in particular those in which the rolling device, when not in use, must be able to be stored in a vehicle hold. The integration of part of the magnetic brake in the wheel also makes it possible to limit the drag generated by the magnetic brake. This provides a wheel equipped with two separate integrated braking devices providing particularly effective braking for a relatively limited size.

[0015] The invention also relates to an aircraft equipped with at least one such taxiing device.

[0016] Other characteristics and advantages of the invention will emerge from reading the following description of particular and non-limiting embodiments of the invention.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Reference will be made to the attached drawings, including:

[0019] - figure 1 is a partial schematic view of an aircraft equipped with taxiing devices according to the invention; - figure 2 is a partial schematic view of a taxiing device according to a first embodiment of the invention, in axial half-section, with the stator of the magnetic brake in the braking position;

[0020] - figure 3 is a view similar to that of figure 2 of this rolling device with the stator of the magnetic brake in the free rotation position;

[0021] - figure 4 is a flowchart illustrating the different operating modes of the magnetic braking device depending on the operating phases of the aircraft;

[0022] - figure 5 is a view similar to that of figure 2 of a rolling device according to a first variant of the first embodiment;

[0023] - figure 6 is a view similar to that of figure 2 of a rolling device according to a second variant of the first embodiment;

[0024] - figure 7 is a partial schematic view of a rolling device according to a second embodiment of the invention, in axial half-section, with the stator of the magnetic brake in the braking position;

[0025] - figure 8 is a view similar to that of figure 7 of this rolling device with the stator of the magnetic brake in the free rotation position;

[0026] - figure 9 is a partial schematic view of a rolling device according to a third embodiment of the invention, in axial section, with the stator of the magnetic brake in the braking position;

[0027] - figure 10 is a view similar to that of figure 9 of this rolling device with the stator of the magnetic brake in the free rotation position;

[0028] - figure 11 is a partial schematic view, along the axis of rotation of the wheel, of the arrangement of the magnets on the stator.

[0029] DETAILED DESCRIPTION OF THE INVENTION With reference to Figures 1 to 3, the first embodiment of the invention is described in application to an aircraft 100 comprising taxiing devices each forming a landing gear mounted on the structure of the aircraft to pivot between an extended position (shown in Figure 1) and a retracted position in a hold 108 under the action of a landing gear actuator 109 known per se and connected to an electronic control unit 110. Each landing gear comprises a leg 101 having one end provided with two coaxial shafts 102 on each of which a wheel 103 is mounted to pivot. Each wheel 103 comprises, in a manner known per se, a hub 104 mounted to pivot on the shaft 102 and a rim 105 which is connected to the hub 104 by a web 106 and which has two annular sidewalls between which a tire is housed.The two shafts 102 are of a single piece, hollow and have an outer surface serving as a bearing for the bearings guiding the hub 104 of each wheel 103 in rotation around the central axis of the shaft 102.

[0030] The rim 105 comprises a first annular portion 105.1 which projects from the web 106 and opposite the hub 104, delimiting therewith a first annular housing 107.1, having one end closed by the web 106 and one end open towards the leg 101. The rim 105 comprises a second annular portion 105.2 projecting from the web 106 opposite the first annular portion 105.1, delimiting a second housing 107.2 of cylindrical shape having one end closed by the web 106 and one end open opposite. The second housing 107.2 is in communication with the internal volume of the shaft 102.

[0031] According to the invention, the wheels 103 are each equipped with a friction braking device housed in the first housing 107.1 and a magnetic braking device housed in the second housing 107.2. The friction braking device comprises rotating movable elements, or rotors 1, and rotating fixed elements, or stators 2.

[0032] More precisely here, the stators 2 and the rotors 1 are in the form of discs, coaxial with the wheel 103, therefore having central axes coincident with the axis of rotation of the wheel 103. The stators 2 and the rotors 1 are arranged alternately and have main faces facing each other and parallel to each other so that they can be pressed against each other and provide friction braking. The stators 2 are linked in rotation to the shaft 102 and to the leg of the landing gear 101, here by means of a torsion tube 3 (or torque tube) secured to a crown 111 secured to the shaft 102, while the rotors 1 are engaged, in a manner known per se, on ribs secured to the first annular part 105.1 of the rim 105 of the wheel 103 to link the rotors 1 in rotation to the wheel 103 while guiding them in translation parallel to the axis of rotation of the wheel 103.

[0033] The torque tube 3 is provided with ribs to form slides allowing each of the stators 2 to slide without rotation on the torque tube 3 in such a way that it is possible to press the stack of disks thus formed by the stators 2 and the rotors 1 and provide a braking force for the wheel 103. The pressing force of the stack of disks is exerted by actuators 4 secured to the ring gear 111 and controllable, in a manner known per se, by the pilot of the aircraft to move the stators 2 so as to be able to press or release the stack of disks and apply, modulate or interrupt the braking force of the wheel 103. The friction braking device is known per se and will not be detailed further here.

[0034] The magnetic braking device comprises a rotor 5 and a stator 6.

[0035] The rotor 5 comprises a sleeve 5.1 engaged in the second annular part 105.2 of the rim 105, and a collar

[0036] 5.2 extending radially outwardly from one end of said sleeve 5.1 opposite the sidewall 106 to extend in front of the sidewall secured to the annular part 105.2 of the rim 105 and parallel to said sidewall. The rotor 5 is rotatably connected to the annular part 105.2, for example by means of screws for fixing the collar 5.2 to the sidewall of the annular part 105.2. The rotor 5 is made of copper or any other electrically conductive material and is provided on the side of the rim 105 with a heat shield 5.3 to limit the transmission of heat to the rim 105 and the tire.

[0037] The stator 6 comprises a main support 6.1 having the shape of a disc having a main face on the periphery of which is fixed a first ring of magnets 7 extending opposite the collar 5.2 of the rotor 5. A sleeve

[0038] 6.2 of circular section projects from said main face so as to be able to be engaged in the sleeve 5.1. The sleeve 6.2 has an outside diameter smaller than an inside diameter of the sleeve 5.1 and has an outside surface provided with a second ring of magnets 8 having an outside diameter smaller than the inside diameter of the sleeve 5.1. The magnets here are based on rare earths; the support 6.1 and the sleeve 6.2 are preferably made of magnetic steel, or even of a non-magnetic material.

[0039] With reference to Figure 11, the first ring of magnets 7 comprises first magnets 11, 13 which have a first magnetization vector substantially perpendicular to the main face of the support 6.1 and which are separated two by two by a second magnet 12, 14 having a second magnetization vector substantially perpendicular to the first magnetization vectors of the first two magnets 11, 13 between which the second magnet 12, 14 is located. It is recalled that the magnetization vector indicates the direction of the magnetic field generated by a magnet and extends, in the magnet, from the South pole to the North pole. More precisely, the magnets 11, 12, 13, 14 have angular sector shapes and have a length measured along a radial direction of the stator 2 and an average width measured along a locally tangential direction of the stator 2 (i.e. perpendicular to the length direction) at half of said length.Lengths and widths are measured in directions locally parallel to the main surface of the support 6.1.

[0040] The magnets 11, 12, 13, 14 are arranged in a Halbach pattern, alternating along the circumferential direction of the ring of magnets 7 (and therefore of the support 6.1) as follows: a magnet 11, a magnet 12, a magnet 13, a magnet 14, a magnet 11, a magnet 12, a magnet 13, a magnet 14 and so on... In this case:

[0041] - each magnet 11 has its magnetization vector which leaves the radial face of the stator 6 (opposite the main face of the support 6.1) towards the collar 5.2 (its North pole opens onto said radial face),

[0042] - each magnet 12 has its magnetization vector which extends from the neighboring magnet 11 towards the neighboring magnet 13,

[0043] - each magnet 13 has its magnetization vector which enters into said radial face (its South pole opens onto said radial face),

[0044] - each magnet 14 has its magnetization vector which extends from the neighboring magnet 11 towards the neighboring magnet 13.

[0045] It is understood that the magnets 12, 14 arranged on each side of the same magnet 11 have their magnetization vector oriented in opposite directions.

[0046] Preferably, according to an advantageous version of the invention, the magnets 11, 12, 13, 14 have widths such that the first magnets 11, 13 are spaced two by two by a first distance (equal to the width of the second magnets) less than a second distance (equal to the width of the first magnets) separating the second magnets 12, 14 two by two. The best results are obtained when the width of the second magnets 12, 14 is approximately 70% of that of the first magnets 11, 13.

[0047] The lengths of the magnets 11, 12, 13, 14 are identical to each other. It is understood that the magnets 12, 14 occupy a smaller surface area on the main face than that of the magnets 11, 13.

[0048] The arrangement of the magnets 11, 12, 13, 14 according to the Halbach pattern makes it possible to optimize and concentrate the magnetic flux produced by the magnets 11, 13 by reducing the return path of the magnetic flux which passes through the magnets 12, 14 and not through the support whose mass can be reduced since it does not need to provide a magnetic flux conduction function.

[0049] With reference again to Figure 11, the magnets of the second ring of magnets 8 have the shape of annular sectors joined to each other around the sleeve 6.2 with the same alternation as those of the first ring 7 to form a Halbach pattern along the circumference of the sleeve 6.2. There will therefore be first magnets 21, 23 which each have a first magnetization vector extending along a local radius (direction locally normal to the outer surface of the sleeve 6.2 opposite the magnet 21, 23 in question) and which are separated two by two by a second magnet 22, 24 having a second magnetization vector substantially tangential to the outer surface of the sleeve 6.2 and contained in a plane perpendicular to the central axis of the sleeve 6.2.

[0050] The magnets 21, 22, 23, 24 are joined by their rectilinear longitudinal edges according to a Halbach pattern, alternating in the circumferential direction of the sleeve 6.2 as follows: a magnet 21, a magnet 22, a magnet 23, a magnet 24, a magnet 21, a magnet 22, a magnet 23, a magnet 24 and so on... In this case:

[0051] - each magnet 21 has its magnetization vector which leaves the outer cylindrical surface of the stator 6 towards the inner surface of the sleeve 5.1 (its North pole opens onto this outer cylindrical surface),

[0052] - each magnet 22 has its magnetization vector which extends from the neighboring magnet 21 towards the neighboring magnet 23,

[0053] - each magnet 23 has its magnetization vector which enters the outer cylindrical surface of the stator 6 (its South pole opens onto the outer cylindrical surface of the stator 6),

[0054] - each magnet 24 has its magnetization vector which extends from the neighboring magnet 21 towards the neighboring magnet 23.

[0055] It is understood that the magnets 22, 24 arranged on each side of the same magnet 21 have their magnetization vectors oriented in opposite directions.

[0056] The stator 6 comprises an operating rod 6.3 slidably engaged in the shaft 2 (the operating rod 6.3 is rotationally connected to the shaft 2, for example, by a rib / groove type system) and mechanically connected to a linear electromechanical actuator 9 housed in the shaft 2 and connected to the electronic control unit 110. The linear electromechanical actuator 9 is arranged to axially move the stator 6 between:

[0057] - a first axial position or braking position (shown in figure 2), and

[0058] - a second axial position or free rotation position (shown in figure 3).

[0059] In the first axial position, the sleeve 6.2 is engaged in the sleeve 5.1 (the magnets 21, 22, 23, 24 are over their entire length opposite the inner surface of the sleeve 5.1 and are separated from it by a radial air gap) and the support 6.1 is brought closer to the collar 5.2 (the magnets 11, 12, 13, 14 are separated from the main surface of the collar 5.2 opposite the rim 105 by a first axial air gap). The first ring of magnets 7 is capable of generating eddy currents in the collar 5.2 of the rotor 5 when the stator 6 is in the first axial position relative to the rotor 5 and the rotor 5 pivots opposite the stator 6. The second ring of magnets 8 is capable of generating eddy currents in the sleeve 5.1 of the rotor 5 when the stator 6 is in its first axial position relative to the rotor 5 and the rotor 5 pivots opposite the stator 6.The generated eddy currents are likely to produce a significant braking force on the rotor 5 depending on the rotational speed of the rotor 5 relative to the stator 6. In the second axial position, the sleeve 6.2 is disengaged from the sleeve 5.1 (the magnets 21, 22, 23, 24 are no longer opposite the inner surface of the sleeve 5.1) and the support 6.1 is moved away from the collar 5.2 (the magnets 11, 12, 13, 14 are separated from the main surface of the collar 5.2 opposite the rim 105 by a second axial air gap greater than the first axial air gap). In this second position, the first ring of magnets 7 and the second ring of magnets 8 are no longer capable of generating in the rotor 5 eddy currents capable of producing a significant braking force on the wheel when the rotor 5 pivots opposite the stator 6 whatever the speed.

[0060] It is understood that to cause braking, the linear electromechanical actuator 9 is driven to bring the stator 6 into the first axial position and that, to interrupt braking, the linear electromechanical actuator 9 is driven to bring the stator 6 into the second axial position, a position in which the magnets do not allow sufficient eddy currents to be generated in the rotor 5 to cause braking of the rotor 5. Between the two positions above, the magnetic braking device can produce intermediate values ​​of braking torque. It will be noted that below a certain rotational speed of the rotor 5, the braking torque is negligible regardless of the position of the stator 6. With reference to FIG. 4, the electronic control unit 110 is arranged to drive the actuators 4, 9 and 109 as follows:

[0061] - when the aircraft is parked on the ground (phase PI), the landing gear 101 being in the extended position, the linear electromechanical actuator 9 is not powered and maintains the stator 6 in the second axial position and the actuator 4 presses the stack of discs;

[0062] - for taxiing maneuvers on the ground (phase P2, also known as taxi), the magnetic brake is used as a speed limiter, actuator 4 being used if necessary if the braking force provided by the magnetic braking device is insufficient;

[0063] - at take-off (phase P3), the linear electromechanical actuator 9 is not powered and maintains the stator 6 in the second axial position;

[0064] - the aircraft having left the ground, the actuator 109 brings the landing gear 101 into the retracted position (phase P4) and the linear electromechanical actuator 9 is powered to bring the stator 6 into the first axial position to reduce the size of the rolling device around the wheel 103;

[0065] - in cruising flight (phase P5), the linear electromechanical actuator 9 is powered to maintain the stator 6 in the first axial position; - for landing, the actuator 109 brings the landing gear 101 into the extended position (phase P6) and the linear electromechanical actuator 9 brings the stator 6 into the second axial position to allow rotation of the wheel;

[0066] - at the moment of contact with the ground (phase P7) then during deceleration (phase P8), the linear electromechanical actuator 9 is powered to bring the stator 6 into the first axial position and the actuator 4 is controlled according to the braking requirements to bring the aircraft to taxiing speed;

[0067] - for driving (P2) and parking (PI), see above.

[0068] Keeping the stator 6 in the braking position makes it possible to reduce the size of the wheel 103 and therefore the length required for its storage in the hold 108.

[0069] Elements identical or similar to those previously described bear the same numerical references in the figures and the rest of the description concerning the variants and the second and third embodiments. In the variant of Figure 5, the stator 6 is equipped with a fan symbolized at 30 to cool the braking devices. Such a fan is known in itself.

[0070] In the variant of Figure 6, the stator 6 is equipped, in addition to the fan 30, with a tachometer 40 or any other device making it possible to measure the rotational speed of the wheel 103. Such a tachometer is known in itself.

[0071] With reference to figures 7 and 8 and according to the second embodiment, the rotor 5 comprises an external sleeve 5.11 and an internal sleeve 5.12 delimiting between them a chute having a bottom partition joining the external sleeve 5.11 and the internal sleeve 5.12.

[0072] The sleeve 6.2 is received in the chute and carries two rings of magnets: - a ring of magnets 8.1 mounted on the outer surface of the sleeve 6.2 to face the outer sleeve 5.11; and

[0073] - a ring of magnets 8.2 mounted on the inner surface of the sleeve 6.2 to face the inner sleeve 5.12.

[0074] The magnet rings 8.1, 8.2 are formed like the magnet ring 8 of the first embodiment.

[0075] The inner surface of the outer sleeve 5.11 and the outer surface of the ring of magnets 8.1 form a first pair of cylindrical surfaces, coaxial with the shaft 102, engaged in each other when the stator 6 is in the braking position and disengaged from each other when the stator 6 is in the free rotation position.

[0076] The outer surface of the inner sleeve 5.12 and the inner surface of the ring of magnets 8.2 form a second pair of cylindrical surfaces, coaxial with the shaft 102, engaged in each other when the stator 6 is in the braking position and disengaged from each other when the stator 6 is in the free rotation position.

[0077] These two pairs of cylindrical surfaces as well as the pair of radial surfaces formed by the main surface of the collar 5.2 and the surface of the facing ring of magnets 7 each allow the passage of magnetic flux. It is understood that this arrangement makes it possible to increase the eddy currents generated in the rotor 5.

[0078] With reference to figures 9 and 10 and according to the third embodiment, the rotor has the same shape as in the second embodiment and the sleeve 6.2 and carries two rings of magnets 8.1, 8.2 as previously.

[0079] The stator 6 comprises two sleeves instead of a single sleeve 6.1, namely an outer sleeve 6.21 and an inner sleeve 6.22, such that the inner sleeve 5.12 can be engaged between the sleeves 6.21, 6.22. The outer sleeve 6.21 has an outer surface facing the outer sleeve 5.11 and provided with a ring of magnets 8.1. The outer sleeve 6.21 has an inner surface facing the inner sleeve 5.12 and provided with a ring of magnets 8.2. The inner sleeve 6.22 has an outer surface facing the inner sleeve 5.12 and provided with a ring of magnets 8.3.

[0080] The magnet rings 8.1, 8.2, 8.3 are formed like the magnet ring 8 of the first embodiment.

[0081] The inner surface of the outer sleeve 5.11 and the outer surface of the ring of magnets 8.1 form a first pair of cylindrical surfaces, coaxial with the shaft 102, engaged in each other when the stator 6 is in the braking position and disengaged from each other when the stator 6 is in the free rotation position.

[0082] The outer surface of the inner sleeve 5.12 and the inner surface of the ring of magnets 8.2 form a second pair of cylindrical surfaces, coaxial with the shaft 102, engaged in each other when the stator 6 is in the braking position and disengaged from each other when the stator 6 is in the free rotation position.

[0083] The inner surface of the inner sleeve 5.12 and the outer surface of the ring of magnets 8.3 form a third pair of cylindrical surfaces, coaxial with the shaft 102, engaged in each other when the stator 6 is in the braking position and disengaged from each other when the stator 6 is in the free rotation position.

[0084] These three pairs of cylindrical surfaces as well as the pair of radial surfaces formed by the main surface of the collar 5.2 and the surface of the facing ring of magnets 7 each allow the passage of magnetic flux.

[0085] It is understood that this arrangement makes it possible to further increase the eddy currents generated in the rotor 5. Preferably, the inner sleeve 5.12 has a thickness such that a skin effect (otherwise called a skin effect or Kelvin effect) is generated from each ring of magnets 8.2, 8.3 over more than half the thickness of the inner flank 5.12 at least over a range of possible relative speeds of the rotor 5 with respect to the stator 6. The eddy currents generated from the two rings of magnets 8.2, 8.3 will then circulate in the central part of the inner flank 5.12, which will increase the braking torque. This results in a “superposition of the skin effects”, the thickness of the inner sleeve 5.12 being sufficiently low to obtain this effect while satisfying the thermal and mechanical constraints. In one example, this effect gives approximately 60% more performance.

[0086] 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.

[0087] In particular, the device may have a structure different from that described.

[0088] The rotor can be moved axially instead of the stator to activate or deactivate magnetic braking.

[0089] The magnets can be carried by the rotor instead of the stator.

[0090] The shape, arrangement and dimensions of the magnets may be different from those described. For example, the magnets 11, 12, 13, 14 all have the same dimensions or, on the contrary, the first magnets 11, 13 represent approximately 70% of the surface of the element which carries them but this is not obligatory. The magnets may have identical or different lengths, identical or different widths, be positioned or not symmetrically on a circle passing through the geometric center of the North poles of the magnets 11 and the South poles of the magnets 13. The use of a Halbach pattern is not obligatory. The number of rotors and / or the number of stators may be different from those mentioned.

[0091] Although in the described embodiments the rotor and stator are arranged to have axial flow (passing through the pair of radial surfaces) and radial flow (passing through the pair(s) of axial surfaces), it is possible to arrange the rotor and stator to have only axial flow or only radial flow.

[0092] The magnetic braking device may use permanent magnets and electromagnets powered via cables passing through the shaft 102 to inhibit or strengthen the magnetic field produced by the permanent magnets, the stator then being fixed in translation. A braking device comprising only electromagnets is also conceivable.

[0093] Generally speaking, actuators can be hydraulic or electric.

[0094] A linear actuator is any actuator whose moving element moves in translation. Thus, an actuator comprising a motor driving a worm screw on which is mounted a nut moving parallel to the worm screw is a linear actuator.

[0095] The friction brake actuators may be electromechanical. Each electromechanical actuator comprises an electric motor and a pusher capable of being moved by the electric motor to press the stack of discs. The electromechanical actuator is thus intended to produce a controlled braking force on the stack of discs. A method of controlling the braking devices is for example known from document FR-A-2953196.

[0096] The invention can be used on any type of vehicle comprising rotating rolling elements.

Claims

DEMANDS 1. A vehicle wheel assembly comprising a leg (101) provided with a shaft (102) and a wheel (103) having a hub (104) mounted to pivot on the shaft, the wheel comprising a rim (105) which is connected to the hub by a disc (106) extending coaxially with the hub, the rim comprising a first annular portion (105.1) which projects from the disc (106) and opposite the hub, defining with it a first annular housing (107.1), having one end closed by the disc and one end open towards the leg to receive a friction braking device, the rim comprising a second annular portion (105.2) which projects from the disc opposite the first annular portion, defining a second housing (107.2) having one end closed by the disc and one end open on the opposite side, characterized in that a device Magnetic braking is mounted in the second housing, and includes: - a first element and a second element which has a surface opposite a surface of the first element and is rotationally mobile relative to the first element, one of the first or second element being rotationally fixed to the shaft and one of the first or second element being rotationally fixed to the wheel, - a control element (9) of the magnetic braking device extending at least partially into the shaft.

2. Rolling device according to claim 1, wherein the first element is made of electrically conductive material and the second element is provided with permanent magnets carrying a plurality of magnets (11, 12, 13, 14; 21, 22, 23, 24) to generate, through the facing surfaces, eddy currents in the first element when the first element rotates relative to the second element.

3. Rolling device according to claim 2, wherein the control member comprises a linear actuator (9) connected to the first element (6) to axially move the first element between a braking position in which the facing surfaces are brought closer together and a free rotation position in which the facing surfaces are moved apart.

4. Device according to claim 3, wherein the facing surfaces comprise two radial surfaces separated by a first axial air gap when the first element (6) is in braking position and by a second axial air gap when the first element is in free rotation position.

5. Device according to any one of claims 3 and 4, wherein the facing surfaces comprise at least a first pair of cylindrical surfaces, coaxial with the shaft (102), engaged with each other when the first element (6) is in the braking position and disengaged from each other when the first element is in the free rotation position.

6. Device according to claim 5, wherein the facing surfaces comprise at least a second pair of cylindrical surfaces, coaxial with the shaft (102), engaged with each other when the first element (6) is in the braking position and disengaged from each other when the first element is in the free rotation position.

7. Device according to claim 6, wherein the facing surfaces comprise at least a third pair of cylindrical surfaces, coaxial with the shaft (102), engaged with each other when the first element (6) is in the braking position and disengaged from each other when the first element is in the free rotation position.

8. Device according to claim 1 or 2, wherein the first element is movable between a position of braking in which the facing surfaces are brought closer together and a free rotation position in which the facing surfaces are far apart, and the first element (6) in the braking position is closer to the leg (101) than in the free rotation position.

9. Device according to any one of the preceding claims, wherein the first element (6) carries a cooling fan (30).

10. Device according to any one of the preceding claims, wherein the first element (6) carries a tachometer (40).

11. A taxiing device according to any one of the preceding claims forming part of an aircraft landing gear.

12. Aircraft comprising a structure to which are fixed at least one taxiing device according to any one of the preceding claims and an actuator (109) for moving the taxiing device between an extended position in which the taxiing device protrudes under the structure and a retracted position in which the taxiing device is received in a compartment (108) of the structure.

13. Aircraft according to the preceding claim, wherein the taxiing device conforms to claim 8 and includes an actuator (9) for moving the first element, this actuator being connected to an electronic control unit (110) programmed to bring the first element (6) into the braking position when the taxiing device is brought into the hold (108).

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