Wheel with magnetic braking device for vehicle, aircraft landing gear and aircraft equipped with such a wheel

Abstract

A vehicle braked wheel (103) comprising at least one hub portion (104.1) and a rim portion (105.1) coaxial with the hub portion (104.1) and connected to the hub portion (104) by a disc portion (106.1), the wheel having an eddy current magnetic braking device comprising a rotor (3) rotationally linked to the wheel and a stator (2) that is rotationally free relative to the rim portion (105.1) and the rotor (3) and that carries a plurality of magnets (11) capable of emitting a magnetic flux generating eddy currents in the rotor (3), made of an electrically conductive material, when the stator (2) and the rotor (3) are facing each other and in relative motion. The rotor (3) is integral with the rim portion (105.1). Landing gear and aircraft comprising such a wheel. FIGURE FROM THE ABRIDGED: Fig. 3

Description

Title of the invention: Wheel with magnetic braking device for vehicle, aircraft landing gear and aircraft equipped with such a wheel

[0001] The present invention relates to the field of braking of vehicle wheels such as aircraft wheels. The invention applies more particularly to magnetic braking devices, that is to say devices in which a magnetic field is used to produce a braking force.

[0002] BACKGROUND OF THE INVENTION

[0003] An aircraft wheel generally comprises a rim connected by a disc to a hub mounted to rotate on a wheel support shaft (axle or spindle).

[0004] Friction braking devices are known to comprise a stack of brake discs housed in a space extending between the rim and the hub, and comprising alternating rotor discs linked in rotation with the wheel and stator discs fixed relative to the wheel support. The braking device also includes hydraulic or electromechanical actuators mounted on an actuator carrier and arranged to apply a controlled braking force to the stack of discs so as to brake the rotation of the wheel.

[0005] Eddy current magnetic braking devices (also called "Eddy current" devices) used for braking vehicle wheels, and more particularly aircraft wheels, are also known. Document WO-A-2014 / 029962 describes such a device comprising a rotor equipped with magnets and mounted on the wheel opposite an electromagnetic stator fixed relative to the landing gear leg carrying the wheel.

[0006] Generally speaking, the performance of an eddy current magnetic braking device depends on the power and dimensions of the magnets used. The braking device is therefore relatively heavy and bulky when the maximum braking power required is significant. This is the case, for example, for use on aircraft, where mass and size are critical constraints for this application.

[0007] SUBJECT OF THE INVENTION

[0008] The invention aims in particular to provide a vehicle wheel equipped with an eddy current magnetic braking device which at least partially remedies the aforementioned disadvantages. Summary of the invention

[0009] For this purpose, according to the invention, a vehicle wheel is provided, comprising at least a hub portion and a rim portion coaxial with the hub portion and connected to the The wheel, consisting of a hub portion and a rim portion, incorporates a magnetic eddy current braking device comprising a rotor fixed in rotation to the wheel and a stator that is free to rotate relative to the rim portion and the rotor. The stator carries a plurality of magnets capable of emitting a magnetic flux that generates eddy currents in the rotor, which is made of an electrically conductive material, when the stator and rotor are facing each other and in relative motion. The rotor is a single piece with the rim portion.

[0010] Thus, at least part of the wheel and the rotor are manufactured as a single piece, for example by casting or additive manufacturing, which improves the integration of the rotor into the wheel and eliminates the need for means of attaching the rotor to the rim. A simpler, more compact, and lighter structure than that of conventional braked wheels can therefore be obtained.

[0011] According to optional features, used individually or in whole or in combination: - the rotor and the stator have radial surfaces facing each other and the magnets are positioned on the stator to emit a magnetic field between these surfaces parallel to a central axis of the wheel; - the rotor includes a ring extending laterally relative to a lip of the rim part and connected to said rim part by a connecting portion, the connecting portion having a cross-section less than a cross-section of the rotor ring; - the rotor and stator have axial surfaces facing each other and the magnets are positioned on the stator to emit a magnetic field between these surfaces perpendicular to a central axis of the wheel; - the rotor includes a tube which is coaxial with the hub part and extends between the rim part and the hub part, the tube has an internal surface forming the axial surface of the rotor; - the rotor and stator have first radial surfaces facing each other and the magnets include first magnets positioned on the stator to emit a magnetic field between the first surfaces parallel to a central axis of the wheel and in which the rotor and stator also have second axial surfaces facing each other and the magnets include second magnets positioned on the stator to emit a magnetic field between the second surfaces perpendicular to a central axis of the wheel; - the wheel includes massive heat storage parts in the vicinity of the rotor, said massive parts being in one piece with the rim part; - the magnets are arranged according to a Halbach pattern.

[0012] The invention also relates to a lander equipped with such a wheel and an aircraft equipped with such a lander.

[0013] Other features and advantages of the invention will become apparent from the following description of particular, non-limiting embodiments of the invention. Brief description of the drawings

[0014] Reference will be made to the attached drawings, among which:

[0015] [Fig-1] [Fig.1] is a partial schematic view of an aircraft equipped of landing gear according to the invention;

[0016] [Fig.2] [Fig.2] is a schematic axial half-sectional view of a wheel along a first embodiment of the invention;

[0017] [Fig.3] [Fig.3] is a partial schematic perspective and half-section view axial of this wheel;

[0018] [Fig.4] [Fig.4] is a view analogous to that of [Fig.2] of a wheel according to a second embodiment of the invention;

[0019] [Fig. 5] [Fig. 5] is a view analogous to that of [Fig. 2] of a wheel according to a third embodiment of the invention;

[0020] [Fig.6] [Fig.6] is a schematic view showing a possible arrangement of the magnets in a wheel according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] With reference to figures 1 to 6, the invention is described in application to an aircraft 100 comprising landers 101. Each lander 101 comprises a leg having a first end articulated to a structure of the aircraft and, opposite, a second, free end, provided with two coaxial shafts 102 on each of which is mounted to pivot a wheel 103. The landers 101 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.

[0022] Each wheel 103 here comprises, in a manner known per se, two half-wheels 103.1, 103.2, each made in one piece and bolted to each other. Each half-wheel 103.1, 103.2 comprises a hub portion 104.1, 104.2 and a rim portion 105.1, 105.2 connected to the hub portion 104.1, 104.2 by a disc portion 106.1, 106.2. Each rim portion 105.1, 105.2 has an annular shape having a first annular edge integral with the disc portion 106.1, 106.2 and a second opposite annular edge provided with a rim or lip 107.1, 107.2. We speak of a half-wheel, but also commonly of a half-rim, half-spoke, or half-hub, even though these parts do not represent half of a wheel, rim, spoke, or hub. Each half-wheel, 103.1 or 103.2, is made of aluminum.

[0023] When the half-wheels 103.1, 103.2 are bolted together: - hub parts 104.1, 104.2 form a hub which can be mounted to pivot on shaft 102; - rim parts 105.1, 105.2 form a rim suitable for receiving a tire between lips 107.1, 107.2; - The disc portions 106.1, 106.2 are pressed against each other by the bolts and form a disc transmitting the forces between the hub and the rim.

[0024] The rim portion 105.1 extends opposite the hub portion 104.1: together they define an annular space having one end at least partially closed by the disc portion 106.1 and, at the opposite end, an open end on the side of the lip 107.1.

[0025] The wheels 103 are equipped with a magnetic braking device generally designated as 1.

[0026] The magnetic braking device 1 comprises a fixed element, or stator 2, and a moving element, or rotor 3. The stator 2 and the rotor 3 are coaxial with the rim portion 105.1; the stator 2, the rotor 3, and the hub portion 104.1 therefore have collinear central axes. The stator 2 has a plurality of magnets capable of generating eddy currents in the rotor 3 when the stator 2 and the rotor 3 are separated by a small air gap and the rotor 3 pivots relative to the stator 2.

[0027] According to the invention, the rotor 3 is one piece with the rim part 105.1 and therefore one piece with the half-wheel 103.1. The rotor 3 and the half-wheel 103.1 are therefore made of the same material, namely aluminium.

[0028] According to the first embodiment shown in Figures 2 and 3, the rotor 3 has the shape of a ring extending in front of the lip 107.1 coaxially therewith. The ring forming the rotor 3 has: - a radial face defining a first main surface 3.1 of the rotor 3, flat, which extends transversely to the central axis of the wheel 103 and which is turned in the opposite direction to the lip 107.1; - an internal perimeter defining a second main surface 3.2 of the rotor 3, cylindrical, which extends axially and defines an internal perimeter of the radial annular part of the crown;

[0029] The rotor 3 is connected to the rim part 105.1 by a connecting ring 4 which extends in the continuation of the second main surface 3.2 and the rim part 105.1 beyond the lip 107.1.

[0030] The connecting ring 4 is pierced with radial holes 5 ensuring several functions and in particular limiting the mass of the wheel 103.

[0031] The stator 2 here has the shape of a ring extending coaxially with the rotor 3 and having an internal axial rim. The stator 2 has an L-shaped cross-section and comprises: - a radial face provided with a first series of magnets defining a first main surface 2.1 of the stator 2, flat, which extends transversely to the central axis of the wheel 103 and which is turned towards the rotor 3; - an inner perimeter provided with a second series of magnets defining a second main surface 2.2 of the stator 2, cylindrical, which extends axially so as to be able to be engaged in the second main surface 3.2 of the rotor 3.

[0032] The stator 2 is rotationally linked to the shaft 102, here by means of a fixing on a flange 102' of the shaft 102 (see [Fig. 3]). Thus, the rotor 3 rotates about its central axis in front of the stator 2, which is fixed to it: during this circumferential movement of the rotor 3, the principal surfaces 3.1, 3.2 remain parallel to the principal surfaces 2.1, 2.2.

[0033] The fixing of the stator 2 on the collar 102' allows the stator 2 to be mobile in sliding without rotation along an axial direction of the shaft 102 between a braking position and a free rotation position of the wheel 103.

[0034] In its braking position, the stator 2 is brought closer to the rotor 3 to the point that the second main surface 2.2 of the stator 2 is engaged in the second main surface 3.2 of the rotor 3: the main surfaces 2.1, 3.1 are separated from each other by a first predetermined air gap and the main surfaces 2.2, 3.2 are separated from each other by a second predetermined air gap.

[0035] In its free rotation position, the stator 2 is separated from the rotor 3 to the point that the second main surface 2.2 of the stator 2 is clear of the second main surface 3.2 of the rotor 3: the main surfaces 2.1, 3.1 are separated from each other by a third predetermined air gap and the main surfaces 2.2, 3.2 are separated from each other by a fourth predetermined air gap.

[0036] In a manner known in itself, at least one linear electromechanical actuator, not shown here, controllable by the pilot of the aircraft, moves the stator 2 between the two positions mentioned above.

[0037] The arrangement of the magnets is shown in [Fig.6]. The magnets, here based on rare earths, are for example 16 in number and are fixed on the ring of the stator 2 possibly via a magnetic steel support, or even on a non-magnetic support.

[0038] The magnets in each series here comprise first magnets 11, 13 having a first magnetization vector substantially perpendicular to the main surface 2.1 and being separated in pairs 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 lies the second magnet 12, 14. It is recalled that the magnetization vector indicates the direction of the The magnetic field generated by a magnet extends within the magnet from the South pole to the North pole. More precisely, magnets 11, 12, 13, and 14 have angular sector shapes and are arranged in a Halbach pattern, alternating along the circumferential direction of the stator 2 as follows: magnet 11, magnet 12, magnet 13, magnet 14, magnet 11, magnet 12, magnet 13, magnet 14, and so on... In this case: - each magnet has its magnetization vector which exits the main face 2.1 (its North pole opens onto the main face 2.1), - each magnet 12 has its own magnetization vector which extends from the neighboring magnet 11 to the neighboring magnet 13, - each magnet 13 has its magnetization vector which enters the main face 2.1 (its South pole opens onto the main face 2.1), - each magnet 14 has its magnetization vector which extends from the neighboring magnet 11 towards the neighboring magnet 13.

[0039] It is understood that the magnets 12, 14 arranged on either side of the same magnet 11 have their magnetization vectors oriented in opposite directions. The arrangement of the magnets 11, 12, 13, 14 optimizes and concentrates 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 their support, the mass of which can be reduced since it does not need to perform a magnetic flux conduction function. The arrangement of the magnets 11, 12, 13, 14 is the same on the principal surfaces 2.1, 2.2.

[0040] It is understood that in order to induce braking, the electromechanical control actuators are driven to bring the stator 2 into the braking position and that, in order to interrupt braking, the electromechanical control actuators are driven to bring the stator 2 into the free rotation position in which the rotor 3, and therefore the wheel 103, can rotate freely.

[0041] In the braking position, the magnets generate sufficient eddy currents in the rotor 3 to produce a braking force on the rotor 3. The circulation of these eddy currents in the rotor 3 tends to cause the rotor 3 to heat up, especially as these currents increase in intensity. It is necessary to limit the heating of the rim portion 105.1 in the vicinity of the tire in order to limit the resulting overheating of the tire. The rotor 3, through which the eddy currents circulate, is therefore designed to have a sufficient volume to store the heat released during braking. Furthermore, the connecting ring 4 has a relatively thin cross-section (in a plane perpendicular to the axis of rotation of the wheel 103), which is smaller than that of the rotor 3, defining a restricted heat transfer area to the rim portion 105.1. The holes 5 allow This passage section is further limited so that the heat from braking can only be dissipated to a very limited extent by conduction to the rim section 105.1. In addition, the holes 5 increase the heat exchange surface area of ​​the connecting ring 4 with the ambient air. Heat will therefore be dissipated from the rotor 3 by radiation, by contact with the airflow over the rotor 3 due to the movement of the wheels and the aircraft, and also by conduction to the rest of the wheel.

[0042] In the free rotation position, the magnets do not generate sufficient eddy currents in the rotor 3 to cause the braking of the rotor 3. It should be noted that below a certain rotational speed of the rotor 3, the braking torque is negligible regardless of the position of the stator 2. It may then be necessary to consider an additional brake.

[0043] In this first embodiment, the annular space formed between the hub portion 104.1 and the rim portion 105.1 is free and can accommodate a stack of stator and rotor discs of a conventional friction brake. The rim portion 105.1 would be provided internally for this purpose with axial ribs 108.1 for rotationally connecting the rotor discs to the wheel, and a torsion tube connected to the shaft 102 would be provided externally with axial ribs for rotationally connecting the stator discs to the shaft 102. The friction brake conventionally comprises a plurality of hydraulic or electromechanical actuators mounted on an actuator carrier fixed to the torsion tube. By way of example, each electromechanical actuator comprises an electric motor and a pusher that can be moved by the electric motor to compress the stack of discs. The electromechanical actuator is thus intended to produce a controlled braking force on the stack of discs.One method of controlling the braking devices is, for example, known from document FR-A-2953196. It should be noted that, in this embodiment with friction brake, the discs act as heat sinks and further limit the risk of heat transfer from the rotor to the tire.

[0044] The identical or analogous elements to those previously described shall bear a numerical reference identical to those in the following description of the second and third embodiments of the invention with reference to figures 4 and 5.

[0045] In both embodiments, the rotor 3 extends within the annular space formed between the hub portion 104.1 and the rim portion 105.1 and has a tubular shape with a circular cross-section. The rotor 3 extends substantially from the lip 107.1 to the disc portion 106.1 without touching it. The rotor 3 has a cylindrical inner surface forming its main surface 3.2 and is fixed externally to the inner surface of the half-rim 105.1 by means of one or more connecting elements 4', 4" depending on the embodiment. These connecting elements 4', 4" are integral with the half-wheel 103.1.

[0046] The stator is not shown in these figures but includes at least a part axial tubular provided with magnets and defining an external cylindrical main surface intended to be engaged in the rotor 3 opposite the main surface 3.2. Optionally, the stator may also include a radial part provided with magnets and intended to extend opposite the front annular face of the rotor (the annular face of the rotor 3 closest to the lip 107.1).

[0047] The connecting elements 4', 4" linking the outside of the rotor 3 to the inner surface of the rim part 105.1 will now be described.

[0048] According to the second embodiment, the connecting elements 4' comprise annular fins extending circumferentially around the rotor 3, having an inner perimeter attached to the rotor 3 and an outer perimeter attached to the rim part 105.1. The annular fins 4' are distributed along the length of the rotor 3 and are pierced with holes 5 which make it possible to limit the mass of the wheel and to increase the surface area for exchange with the ambient air.

[0049] The wheel part 103.1 according to the second embodiment is preferably made by additive manufacturing.

[0050] According to the third embodiment, the connecting element 4” is a single, relatively thick annular wing extending circumferentially around the rear end of the rotor 3 (the one adjacent to the sail part 106.1) having an inner perimeter attached to the rotor 3 and an outer perimeter attached to the rim part 105.1.

[0051] An annular space 6 is provided between the rotor 3 and the inner surface of the rim part 105.1 to limit the mass of the wheel.

[0052] The wheel part 103.1 according to the third embodiment is preferably made in a foundry.

[0053] It is understood that, in all embodiments, the rotor 3 is a single piece with the wheel section 103.1 and that the half-wheel 103.1 serves, in whole or in part, as a heat sink, taking care to prevent heat transfer to the tire. The rotor 3, the ribs 108.1, and the annular wing 4” are relatively large: their volume is determined to give them sufficient thermal capacity to form a massive heat storage area, limiting the risk of heat transfer to the tire. The perforated annular wings 4’ will, in turn, promote heat dissipation by the air circulating around the rotor 3.

[0054] 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.

[0055] In particular, the wheel may have a different structure from that described.

[0056] A rim part (serving as a support for the tire) can be attached to a part of the rim and / or a part of the rim can be attached to a part of the hub.

[0057] Instead of being formed from two half-wheels, the wheel can be a single piece, produced in a foundry or by additive manufacturing.

[0058] The wheel can be made of any electrically conductive material having mechanical properties compatible with the intended application.

[0059] The shape, arrangement, and dimensions of the magnets may differ from those described. For example, magnets 11, 12, 13, and 14 may be identical or occupy different areas by having different widths and / or lengths. The use of a Halbach pattern is not mandatory.

[0060] The magnetic braking device can be axial flux (the rotor and stator have only radial surfaces as their main surfaces), radial flux (the rotor and stator have only axial surfaces as their main surfaces as in Figures 4 and 5) or combine axial and radial flux (the rotor and stator have axial and radial main surfaces as in Figures 2 and 3).

[0061] Generally speaking, the actuators can be electromechanical, hydromechanical, or hydraulic, single- or double-acting. For a single-acting actuator, the power supply enables forward movement of the pusher, and an elastic element enables the pusher's return. The number of actuators may differ from that mentioned. Preferably, at least three actuators symmetrically distributed around the wheel's axis of rotation will be used to balance the axial forces exerted on the stators.

[0062] Other modes of actuation of the magnetic brake are conceivable: for example electromagnetic by means of coils generating a magnetic field canceling that of the permanent magnets, rotors and stators being axially fixed.

Claims

Demands

1. Lander (101) comprising a leg having an end carrying a shaft (102) on which is mounted a wheel hub (103), the wheel (103) comprising at least one hub portion (104.1) and a rim portion (105.1) coaxial with the hub portion (104.1) and connected to the hub portion (104.1) by a disc portion (106.1), the wheel comprising an eddy current magnetic braking device (1) comprising a rotor (3) one-piece with the rim portion (105.1) and a stator (2), rotationally connected to the leg and rotatable relative to the rim portion (105.1) and the rotor (3), carrying a plurality of magnets (11, 12, 13, 14) capable of emitting a magnetic flux generating currents in the rotor (3), made of electrically conductive material. Foucault when the stator (2) and the rotor (3) are facing each other and in relative motion.

2. Lander (101) according to claim 1, wherein the rotor (3) and the stator (2) have radial surfaces (3.1, 2.1) facing each other and the magnets (11, 12, 13, 14) are positioned on the stator (2) to emit a magnetic field between these surfaces parallel to a central axis of the wheel (103).

3. Lander (101) according to claim 2, wherein the rotor (3) comprises a ring extending laterally from a lip (107.1) of the rim portion (105.1) and connected to said rim portion (105.1) by a connecting portion, the connecting portion having a cross-section less than a cross-section of the rotor ring (3).

4. Lander (101) according to claim 1, wherein the rotor (3) and the stator (2) have axial surfaces (3.2, 2.2) facing each other and the magnets (11, 12, 13, 14) are positioned on the stator (2) to emit a magnetic field between these surfaces perpendicular to a central axis of the wheel (103).

5. Lander (101) according to claim 4, wherein the rotor (3) comprises a tube which is coaxial with the hub part (104.1) and extends between the rim part (105.1) and the hub part (104.1), the tube has an internal surface forming the axial surface (3.2) of the rotor (3).

6. Lander (101) according to claim 1, wherein the rotor (3) and the stator (2) have first radial surfaces (3.1, 2.1) facing each other and the magnets (11, 12, 13, 14) comprise first magnets positioned on the stator (2) to emit a magnetic field between the first surfaces (3.1, 2.1) parallel to a central axis of the wheel (103) and wherein the rotor (3) and the stator (2) also have second axial surfaces (3.2, 2.2) facing each other and the magnets (11, 12, 13, 14) comprise second magnets positioned on the stator (2) to emit a magnetic field between the second surfaces (3.2, 2.2) perpendicular to a central axis of the wheel (103).

7. Lander (101) according to any one of the preceding claims, comprising solid parts (108.1) for heat storage in the vicinity of the rotor (3), said solid parts being in one piece with the rim part (105.1).

8. Lander (101) according to any one of the preceding claims, wherein the magnets (11, 12, 13, 14) are arranged in a Halbach pattern.

9. Aircraft comprising a structure on which is mounted at least one landing gear according to claim 1.

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