Magnetic braking device for a braked wheel of an aircraft landing gear
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-29
- Publication Date
- 2026-04-08
Smart Images
Figure EP2024064788_05122024_PF_FP_ABST
Abstract
Description
[0001] MAGNETIC BRAKING DEVICE FOR BRAKED WHEEL OF AN AIRCRAFT LANDING GEAR
[0002] The present invention relates to the field of braking vehicle wheels such as aircraft wheels. The invention applies more particularly to magnetic braking devices, i.e. devices in which a magnetic field is selectively used to produce a braking force.
[0003] BACKGROUND OF THE INVENTION
[0004] 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. The aircraft wheel is traditionally provided with a braking device to slow and stop the aircraft when on the ground.
[0005] Eddy current magnetic braking devices are known, used for braking vehicle wheels and more particularly aircraft wheels. The magnetic braking device generally comprises a rotor which is attached to the wheel opposite a stator mounted to slide relative to the axle. One of the rotor and the stator is provided with permanent magnets or electromagnets (or even a combination of the two) forming a first main surface, while the other of said rotor and said stator is composed of an electrically conductive material forming a second main surface. The sliding of the stator is generally subject to hydraulic or electromechanical actuators arranged to selectively bring said stator closer to the rotor so as to generate a braking torque on said rotor and thus brake the rotation of the wheel.The magnetic braking device can be axial flux, radial flux or both in order to increase the performance of the magnetic braking device.
[0006] SUBJECT OF THE INVENTION
[0007] The aim of the invention is to propose a particular arrangement of the magnets of a radial and axial flux magnetic braking device making it possible to optimize the performance of said magnetic braking device.
[0008] SUMMARY OF THE INVENTION
[0009] To this end, according to the invention, a magnetic braking device is provided comprising a stator and a rotor, one of the stator and the rotor comprising a first series of magnets defining a main surface which extends radially and which is turned towards the other of the stator and the rotor to emit between said stator and said rotor an axial magnetic flux, and one of the stator and the rotor comprising a second series of magnets defining a second main surface which extends axially to be able to receive or be engaged in the other of the stator and the rotor to emit between said stator and said rotor a radial magnetic flux.
[0010] According to the invention, the first series of magnets comprises, alternately, at least first magnets and second magnets having a magnetization vector perpendicular to the first main surface, the magnetization vector of these first magnets and these second magnets respectively exiting and re-entering the first main surface. The second series of magnets comprises, alternately, at least first magnets and second magnets having a magnetization vector perpendicular to the second main surface, the magnetization vector of these first magnets and these second magnets respectively exiting and re-entering the second main surface.The first series of magnets and the second series of magnets are angularly offset from each other such that each first magnet and second magnet of the first series of magnets extends respectively, along a radial plane, opposite a second magnet and a first magnet of the second series of magnets.
[0011] This particular offset of the first series of magnets relative to the second series of magnets allows said first series of magnets and said second series of magnets to together emit a transverse magnetic flux between the stator and the rotor and to generate an additional braking torque on the wheel, this transverse magnetic flux being added to the axial and radial magnetic fluxes.
[0012] According to a particular characteristic of the invention, one of the stator and the rotor comprises the first series of magnets and the second series of magnets.
[0013] In particular, the stator comprises the first series of magnets and the second series of magnets.
[0014] Advantageously, the magnets of the first series of magnets and the magnets of the second series of magnets are arranged in a Halbach pattern.
[0015] In particular, the magnetic braking device comprises at least one actuator arranged to move the rotor and the stator relatively to each other along the axis of rotation of the rotor between a position of free rotation of the rotor and a braking position of the rotor.
[0016] The invention also relates to a braked vehicle wheel mounted for rotation on an axle and equipped with such a magnetic braking device, the rotor and the stator being respectively integral in rotation with the wheel and the axle.
[0017] The invention also relates to an aircraft landing gear comprising at least one such wheel. The invention further relates to an aircraft comprising at least one such landing gear.
[0018] BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention will be better understood in light of the following description, which is purely illustrative and not limiting, and must be read in conjunction with the appended drawings, among which:
[0020] [Fig.l] Figure 1 is a simplified representation of an aircraft comprising braked wheels according to a particular embodiment of the invention;
[0021] [Fig.2] Figure 2 is a partial schematic view in perspective and in axial section in angular sector of one of the braked wheels of the aircraft illustrated in Figure 1, with the friction braking device in a braking state and the magnetic braking device in a braking state;
[0022] [Fig.3] Figure 3 is an axial half-sectional view of the braked wheel illustrated in Figure 2, according to plane III of Figure 2, with the friction braking device in the braking state;
[0023] [Fig.4A] Figure 4A is an axial half-sectional view of the braked wheel illustrated in Figure 2, along the plane of IV of Figure 2, with the magnetic braking device in the braking state;
[0024] [Fig.4B] Figure 4B is a view similar to Figure 4A, with the magnetic braking device in a released state;
[0025] [Fig.5] Figure 5 is a schematic perspective view of the stator of the magnetic braking device shown in Figures 4A-4B;
[0026] [Fig.6A] Figure 6A illustrates the evolution of the braking torque generated by the first series of magnets equipping the stator illustrated in Figure 5; [Fig.6B] Figure 6B illustrates the evolution of the braking torque generated by the second series of magnets equipping the stator illustrated in Figure 5;
[0027] [Fig.6C] Figure 6C illustrates the evolution of the braking torque generated by the first series of magnets and the second series of magnets equipping the stator illustrated in Figure 5;
[0028] [Fig.7] Figure 7 is a partial schematic view of a variant of the stator shown in Figure 5.
[0029] DETAILED DESCRIPTION OF THE INVENTION
[0030] With reference to Figure 1, the invention is described in application to an aircraft 100 comprising two main landing gears 101. Each landing gear 101 comprises a leg having a first end articulated to a structure of the aircraft and, opposite, a second end carrying wheels 103 rotating around an axis X on a tubular axle 102. The landing gears 101 are here of the retractable type but the invention is applicable to fixed landing gears, or even to another type of vehicle such as a land vehicle.
[0031] The wheels 103 are said to be “braked”, that is to say equipped with a brake F intended to selectively slow down and stop the aircraft 100 when it is on the ground. The following description relates to one of the wheels 103 of the aircraft 100, the wheels 103 being identical here but also being able to be different.
[0032] With reference to Figure 2, the wheel 103 here comprises, in a manner known per se, two half-wheels which are each made in a single piece and which are bolted to each other. Each half-wheel comprises a hub part
[0033] 104.1, 104.2 and a rim portion 105.1, 105.2 connected to the hub portion 104.1, 104.2 by a web portion
[0034] 106.1, 106.2. Each rim part 105.1, 105.2 has an annular shape having a first annular edge integral with the web part 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-web, half-hub even though these parts do not represent half of a wheel, rim, web, hub. Each half-wheel is here made of aluminum.
[0035] When the half wheels are bolted together:
[0036] - the hub parts 104.1, 104.2 form a hub which can be mounted for pivoting on the axle 102;
[0037] - the rim parts 105.1, 105.2 form a rim capable of receiving a tire between the lips 107.1, 107.2; and
[0038] - the web parts 106.1, 106.2 are pressed against each other by the bolts and form a web transmitting the forces between the hub and the rim.
[0039] The rim part 105.1 extends opposite the hub part 104.1: together they define an annular space 108 having one end at least partially closed by the web part 106.1 and, opposite, an open end on the side of the lip 107.1.
[0040] The brake F of the wheel 103 comprises a friction braking device generally designated 50 and a magnetic braking device generally designated 1.
[0041] Referring to Figure 3, the friction braking device 50 comprises a torque tube 51 extending around the hub portion 104.1, in the annular space 108. The torque tube 51 has a first end which is provided with an internal flange fixed to a flange 102' of the axle 102, and a second end, opposite the first end, which is provided with an external flange extending in the vicinity and facing the web portion 106.1.
[0042] On the torque tube 51 is threaded a stack of friction discs comprising alternately a rotor disc 52 connected in rotation with the rim part 105.1, and two stator discs 53 fixed in rotation relative to the torque tube 51 and therefore to the axle 102. The rotor disc 52 is for example engaged to slide axially on massive axial ribs 109 extending from the rim part 105.1 radially projecting into the annular space 108. The stator discs 53 are for example engaged to slide axially on axial ribs (not visible in the figures) extending from an external surface of the torque tube 51 radially projecting into the annular space 108.
[0043] The friction braking device 50 also comprises an actuator-carrying ring 54, transverse to the axle 102, which partially closes the annular space 108 opposite the web portion 106.1 and which comprises first cylindrical housings 55 (here four in number), open on the side of the annular space 108 and blind on the opposite side. The first housings 55 are each formed by a tube with a central axis parallel to the axis X of rotation of the wheel 103 and are symmetrically distributed around said axis X. Each first housing 55 receives an actuator 56, here hydraulic, having a piston movable along the central axis of the first housing 55 to bear on the stack of discs in order to apply a controlled braking force on said stack of discs in abutment against the collar of the second end of the torque tube 51 so as to brake the rotation of the wheel 103.The actuators 56 are connected to a fluid source and are controlled in a manner known per se.
[0044] With reference to Figures 4A and 4B, the magnetic braking device 1 comprises a fixed rotating element, or stator 2, and a mobile rotating element, or rotor 3. The stator 2 and the rotor 3 here have respectively the shape of a disc and a crown having central axes merged with the axis X of rotation of the wheel 103. In the present embodiment, the rotor 3 is in one piece with the rim part 105.1 and therefore in one piece with the corresponding half-wheel. The rotor 3 and the corresponding half-wheel are therefore made of the same material, namely aluminum.
[0045] The crown forming the rotor 3 extends here in front of the lip 107.1 and comprises:
[0046] - a radial face defining a first main surface 3.1 of the rotor 3, flat, which extends transversely to the axis X of rotation of the wheel 103 and which is turned away from the lip 107.1; and
[0047] - an internal periphery defining a second main surface 3.2 of the rotor 3, cylindrical, which extends coaxially to the axis X of rotation of the wheel 103 and which defines an internal periphery of the radial annular part of the crown.
[0048] The rotor 3 is connected to the rim portion 105.1 by a connecting ring 4 which extends in the extension of the second main surface 3.2 and the rim portion 105.1 beyond the lip 107.1. The connecting ring 4 is pierced with radial holes 5 ensuring several functions and in particular to limit the mass of the wheel 103.
[0049] The disc forming the stator 2 extends opposite the rotor 3 coaxially with it and has an internal axial rim. The stator 2 thus has an L-shaped cross-section and comprises:
[0050] - a radial face provided with a first series of magnets 10.1 defining a first main surface 2.1 of the stator 2, flat, which extends transversely to the axis X of rotation of the wheel 103 and which is turned towards the first main surface 3.1 of the rotor 3; and
[0051] - an external periphery of the internal axial rim provided with a second series of magnets 10.2 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.
[0052] The first series of magnets 10.1 is arranged so as to emit a first axial magnetic flux generating eddy currents in the rotor 3 when the first main surface 3.1 of said rotor 3 is separated from the first main surface 2.1 of the stator 2 by a small axial air gap, and said rotor 3 pivots relative to said stator 2.
[0053] The second series of magnets 10.2 is arranged so as to emit a second radial magnetic flux generating eddy currents in the rotor 3 when the second main surface 3.2 of said rotor 3 is separated from the second main surface 2.2 of the stator 2 by a small radial air gap, and said rotor 3 pivots relative to said stator 2.
[0054] The stator 2 is connected in rotation to the axle 102 by a web 6 subject in translation to actuator pistons 7 (here four in number), here electromechanical, received in second housings 57 of the actuator-carrying ring 54. More precisely, the stator 2 is blocked in rotation relative to the axle 102 by the contact of the web 6 on the actuator-carrying ring 54 which is itself fixed to the axle 102. Screws 63 control the translation of the stator 2 to the movements of the pistons of the actuators 7. The second housings 57 are open opposite the annular space 108 and blind on the side of the annular space 108. The second housings 57 are each formed of a tube with a central axis parallel to the axis X of rotation of the wheel 103 and are symmetrically distributed relative to said axis X of rotation. of wheel 103 and in relation to the first housings 55.The pistons of the actuators 7 are movable along the axis X of rotation of the wheel 103 to move the stator 2 between a maximum braking position of the wheel 103 and a position of free rotation of the wheel 103.
[0055] It is understood that the pistons of the actuators 7 of the magnetic braking device 1 move in directions parallel to the directions of movement of the pistons of the actuators 56 of the friction braking device 50 but in opposite directions (in FIG. 2, the pistons of the actuators 7 come out by moving to the left while the pistons of the actuators 56 come out by moving to the right): it is said that the actuators 7 are placed in opposition with respect to the actuators 56.
[0056] Thus, the rotor 3 rotates on itself around its central axis in front of the stator 2 which is fixed in rotation: during this movement of the rotor 3 in a circumferential direction, the first main surface 3.1 and the second main surface 3.2 of the rotor 3 remain respectively parallel to the first main surface 2.1 and the second main surface 2.2 of the stator 2. At the same time, the stator 2 is axially movable between the maximum braking position and the free rotation position.
[0057] In its maximum 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 first main surface 2.1 of the stator 2 and the first main surface 3.1 of the rotor 3 are axially separated from each other by a first predetermined air gap, and the second main surface 2.2 of the stator 2 and the second main surface 3.2 of the rotor 3 are radially separated from each other by a second predetermined air gap.
[0058] In its free rotation position, the stator 2 is spaced 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 first main surface 2.1 of the stator 2 and the first main surface 3.1 of the rotor 3 are axially separated from each other by a third predetermined air gap, and the second main surface 2.2 of the stator 2 and the second main surface 3.2 of the rotor 3 are radially separated from each other by a fourth predetermined air gap.
[0059] It is understood that in the maximum braking position, the first series of magnets 10.1 and the second series of magnets 10.2 generate in the rotor 3 eddy currents sufficient to generate respectively a first braking torque Ci and a second braking torque Ci on said rotor 3, and that in the free rotation position, this first braking torque Ci and this second braking torque Ci are negligible (that is to say they are not sufficient to cause a significant slowing of the aircraft), or even non-existent, whatever the rotation speed of the wheel 103 around its rotation axis X.
[0060] The stator 2 is guided in translation between its maximum braking position and its free rotation position by guide studs 8, here of cylindrical shape, each partially received in a notch 9 formed in an internal periphery of the damper plate 6 (visible in FIG. 3). Each guide stud 8 is formed by a tube which extends coaxially to one of the first housings 55 on one side of the actuator-carrying ring 54 opposite said first housing 55. More precisely, the tube forming each guide stud 8 extends the tube forming one of the first housings 55 on the side of the actuator-carrying ring 54 opposite the annular space 108.
[0061] It is understood that to cause braking, the actuators 7 are controlled to bring the stator 2 from the free rotation position to the braking position and that, to interrupt braking, the actuators 7 are controlled to return the stator 2 to the free rotation position.
[0062] Below a certain rotational speed of the rotor 3, the braking torque is negligible regardless of the position of the stator 2: the friction braking device is then actuated by powering the actuators 56 to cause the application of the pressing force on the stack of discs. The friction braking device is also used as a parking brake.
[0063] The braking force exerted on the friction braking device is released by evacuating the fluid from the actuators 56.
[0064] The braking force exerted on the magnetic braking device is released by bringing the stator 2 towards its free rotation position. In the free rotation position of the stator 2, the first series of magnets 10.1 and the second series of magnets 10.2 do not allow sufficient eddy currents to be generated in the rotor 3 to cause braking of the rotor 3.
[0065] The particular arrangement of the first series of magnets 10.1 and the second series of magnets 10.2 is shown in Figure 5. The magnets 10.1, 10.2 are here based on rare earths and are fixed to the crown of the stator 2 possibly via a magnetic steel support, or even on a non-magnetic support.
[0066] The first series of magnets 10.1 here comprises first magnets 11.1, 13.1 which have a first magnetization vector substantially perpendicular to the first main surface 2.1 of the stator 2, and which are separated two by two by second magnets 12.1, 14.1 having a second magnetization vector substantially perpendicular to the first magnetization vectors of the first magnets 11.1, 13.1 between which the second magnet 12.1, 14.1 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 specifically, the first and second magnets 11.1, 13.1, 12.1, 14.1 have angular sector shapes and are arranged in a Halbach pattern, alternating along the circumferential direction of the stator 2 as follows: a first magnet 11.1, a second magnet 12.1, a first magnet 13.1, a second magnet 14.1, a first magnet 11.1, a second magnet 12.1, a first magnet 13.1, a second magnet 14.1 and so on... In this case:.
[0067] - each first magnet 11.1 has its magnetization vector which leaves the first main face 2.1 of the stator 2 (its North pole opens onto the first main face 2.1);
[0068] - each second magnet 12.1 has its magnetization vector extending from the first neighboring magnet 11.1 to the first neighboring magnet 13.1;
[0069] - each first magnet 13.1 has its magnetization vector which enters the first main face 2.1 of the stator 2 (its South pole opens onto the first main face 2.1); and
[0070] - each second magnet 14.1 has its magnetization vector extending from the first neighboring magnet 11.1 to the first neighboring magnet 13.1.
[0071] It is understood that the first magnets 11.1, 13.1 arranged on each side of the same second magnet 12.1 have their magnetization vector oriented in opposite directions and that the second magnets 12.1, 14.1 arranged on each side of the same first magnet 13.1 have their magnetization vector oriented in opposite directions. The arrangement of the first and second magnets 11.1, 13.1, 12.1, 14.1 makes it possible to optimize and concentrate the axial magnetic flux produced by the first magnets 11.1, 13.1 by reducing the return path of the magnetic flux which passes through the second magnets 12.1, 14.1 and not through their support whose mass can be reduced since it does not need to ensure a magnetic flux conduction function.
[0072] The second series of magnets 10.2 here comprises first magnets 11.2, 13.2 which have a first magnetization vector substantially perpendicular to the second main surface 2.2 of the stator 2, and which are separated two by two by second magnets 12.2, 14.2 having a second magnetization vector substantially perpendicular to the first magnetization vectors of the first magnets 11.2, 13.2 between which the second magnet 12.2, 14.2 is located.
[0073] The arrangement of the first and second magnets 11.2, 13.2, 12.2, 14.2 is similar to that of the first and second magnets 11.1, 13.1, 12.1, 14.1: the first and second magnets 11.2, 13.2, 12.2, 14.2 have the shape of portions of angular cylinders and are arranged in a Halbach pattern, alternating along the circumferential direction of the stator 2, so that:
[0074] - each first magnet 11.2 has its magnetization vector which comes out of the second main face 2.2 of the stator 2 (its North pole opens onto the second main face 2.2);
[0075] - each second magnet 12.2 has its magnetization vector extending from the first neighboring magnet 11.2 to the first neighboring magnet 13.2;
[0076] - each first magnet 13.2 has its magnetization vector which enters the second main face 2.2 of the stator 2 (its South pole opens onto the second main face 2.2); and
[0077] - each second magnet 14.2 has its magnetization vector extending from the first neighboring magnet 11.2 to the first neighboring magnet 13.2.
[0078] It is understood that the first magnets 11.2, 13.2 arranged on each side of the same second magnet 12.2 have their magnetization vector oriented in opposite directions and that the second magnets 12.2, 14.2 arranged on each side of the same first magnet 13.2 have their magnetization vector oriented in opposite directions. The arrangement of the first and second magnets 11.2, 13.2, 12.2, 14.2 makes it possible to optimize and concentrate the radial magnetic flux produced by the first magnets 11.2, 13.2 by reducing the return path of the magnetic flux which passes through the second magnets 12.2, 14.2 and not through their support whose mass can be reduced since it does not need to provide a magnetic flux conduction function.
[0079] Referring to Figure 5, it is noted that the first series of magnets 10.1 and the second series of magnets 10.2 are angularly offset from each other, so that:
[0080] - each first magnet 11.1 of the first series of magnets 10.1 extends opposite a first magnet
[0081] 13.2 of the second series of magnets 10.2, according to a radial plane;
[0082] - each second magnet 12.1 of the first series of magnets 10.1 extends opposite a second magnet
[0083] 14.2 of the second series of magnets 10.2, according to a radial plane;
[0084] - each first magnet 13.1 of the first series of magnets 10.1 extends opposite a first magnet
[0085] 11.2 of the second series of magnets 10.2, according to a radial plane; and
[0086] - each second magnet 14.1 of the first series of magnets 10.1 extends opposite a second magnet
[0087] 12.2 of the second series of magnets 10.2, according to a radial plane;
[0088] This particular offset of the first series of magnets 10.1 relative to the second series of magnets 10.2 allows said first series of magnets 10.1 and said second series of magnets 10.2 to together emit a third transverse magnetic flux generating eddy currents in the rotor 3 when the first main surface 3.1 and the second main surface 3.2 of said rotor 3 are separated respectively from the first main surface 2.1 and the second main surface 2.2 of the stator 2 by a small axial air gap, and said rotor 3 pivots relative to said stator 2.
[0089] It is understood that in the maximum braking position, the first series of magnets 10.1 and the second series of magnets 10.2 together generate in the rotor 3 eddy currents sufficient to generate a third braking torque Ca on said rotor 3, and that in the free rotation position, this third braking torque Ca is negligible (that is to say it is not sufficient to cause a significant slowing of the aircraft), or even non-existent, whatever the speed of rotation of the wheel 103 around its axis X of rotation.
[0090] To prove the generation of this third braking torque Ca, simulations were carried out, the results of which are illustrated in Figure 6A-6C.
[0091] Figure 6A illustrates the evolution of the braking torque exerted on the wheel 103 by the magnetic braking device 1 when the stator 2 is in its maximum braking position and the wheel 103 rotates at a speed equal to 1300 revolutions per minute, in the absence of the second series of magnets 10.2: Figure 6A thus illustrates the evolution of the first braking torque Ci generated by the first series of magnets 10.1. The first braking torque Ci is on average substantially equal to 600 Newton meters (Nm).
[0092] Figure 6B illustrates the evolution of the braking torque exerted on the wheel 103 by the magnetic braking device 1 when the stator 2 is in its maximum braking position and the wheel 103 rotates at a speed equal to 1300 revolutions per minute, in the absence of the first series of magnets 10.1: Figure 6B thus illustrates the evolution of the second braking torque C2 generated by the second series of magnets 10.2. The second braking torque C2 is on average substantially equal to 315 Newton meters (Nm).
[0093] Figure 6C illustrates the evolution of the braking torque exerted on the wheel 103 by the magnetic braking device 1 when the stator 2 is in its maximum braking position and the wheel 103 rotates at a speed equal to 1300 revolutions per minute, in the presence of the first series of magnets 10.1 and the second series of magnets 10.2: Figure 6C thus illustrates the evolution of the overall braking torque C ggenerated by the first series of magnets 10.1 and the second series of magnets 10.2. This overall braking torque C g is on average substantially equal to 1005 Newton meters (Nm) and is therefore greater than the sum of the first braking torque Ci and the second braking torque C2 which is on average equal to 915 Newton meters. The particular offset of the first series of magnets 10.1 relative to the second series of magnets 10.2 thus allows an increase of approximately 10% in the braking torque generated by the magnetic braking device 1.
[0094] Figure 7 illustrates a stator 2' which is nothing other than a variant of the stator 2. The stator 2' differs from the stator 2 in that it comprises a first series of magnets 10.1' comprising alternating first magnets 11.1' and second magnets 12.1', a second series of magnets 10.2' comprising alternating first magnets 11.2' and second magnets 12.2'.
[0095] The first and second magnets 11.1', 12.1' of the first series of magnets 10.1' have a magnetization vector substantially perpendicular to the first main surface 2.1 of the stator 2. More precisely, each first magnet 11.1' has its magnetization vector which leaves the first main face 2.1 of the stator 2 (its North pole opens onto the first main face
[0096] 2.1), and each second magnet 12.1' has its magnetization vector which fits into the first main face
[0097] 2.1 of stator 2 (its South pole opens onto the first main face 2.1). We understand that the first magnets 11.1' and the second magnets 12.1' have their magnetization vector oriented in opposite directions.
[0098] The first and second magnets 11.2', 12.2' of the second series of magnets 10.2' have a magnetization vector substantially perpendicular to the second main surface 2.2 of the stator 2. More precisely, each first magnet 11.2' has its magnetization vector which leaves the second main face 2.2 of the stator 2 (its North pole opens onto the second main face
[0099] 2.2), and each second magnet 12.2' has its magnetization vector which fits into the second main face
[0100] 2.2 of stator 2 (its South pole opens onto the second main face 2.2). We understand that the first magnets 11.2' and the second magnets 12.2' have their magnetization vector oriented in opposite directions.
[0101] Note that the first series of magnets 10.1' and the second series of magnets 10.2' are angularly offset from each other, so that:
[0102] - each first magnet 11.1' of the first series of magnets 10.1' extends opposite a second magnet 12.2' of the second series of magnets 10.2', along a radial plane; and
[0103] - each second magnet 12.1' of the first series of magnets 10.1' extends opposite a first magnet 11.2' of the second series of magnets 10.2', along a radial plane.
[0104] We understand that in the maximum braking position:
[0105] - the first series of magnets 10.1' emits a first axial magnetic flux generating eddy currents in the rotor 3 when the rotor 3 pivots relative to said stator 2, these currents being sufficient to generate a first braking torque on said rotor 3;
[0106] - the second series of magnets 10.2' emits a second radial magnetic flux generating eddy currents in the rotor 3 when the rotor 3 pivots relative to said stator 2, these currents being sufficient to generate a second braking torque on said rotor 3; and
[0107] - the first series of magnets 10.1' and the second series of magnets 10.2' together emit a third transverse magnetic flux generating eddy currents in the rotor 3 when the rotor 3 pivots relative to said stator 2, these currents being sufficient to generate a third braking torque on said rotor 3.
[0108] 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.
[0109] In particular, the wheel may have a different structure than described.
[0110] The friction braking device may have a structure different from that described. It may comprise a different number of stator discs (for example one or more than two) and / or rotor discs (for example more than two). The actuators may be electromechanical actuators and not hydraulic actuators. For example, 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.
[0111] The friction braking device is optional.
[0112] Generally, actuators can be electromechanical or hydraulic, single or double acting. For a single acting actuator, the power supply allows the piston to move forward and an elastic element allows the piston to return. The number of actuators may be different from that mentioned. Preferably, at least three symmetrically distributed actuators will be used for each braking device.
[0113] A part of the rim (serving as a support for the tire) can be attached to a part of the wheel and / or a part of the wheel can be attached to a part of the hub.
[0114] Instead of being formed from two half-wheels, the wheel 103 can be a single piece, made in a foundry or by additive manufacturing.
[0115] Rotor 3 can be attached to wheel 103.
[0116] The first series of magnets 10.1 and the second series of magnets 10.2 can be carried by the rotor 3 instead of the stator 2.
[0117] One of the first and second series of magnets 10.1, 10.2, 10.1', 10.2' can be carried by the stator 2 while the other of the first and second series of magnets 10.1, 10.2, 10.1', 10.2' is carried by the rotor 3.
[0118] The number, shape, arrangement and dimensions of the magnets may be different from those described and illustrated. For example, the magnets 11.1, 11.1', 11.2, 11.2', 12.1, 12.1', 12.2, 12.2', 13.1, 13.2, 14.1, 14.2 may be identical to each other or occupy different areas by having different widths and / or lengths. The Halbach pattern arrangement is advantageous but is not mandatory. Although the magnets here are permanent magnets, they may be replaced by electromagnets.
[0119] The actuator carrier ring 54 can be fixed directly to the axle 102. The torque tube 51 can be fixed to the actuator carrier ring 54.
[0120] The tubular arrangement of the guide studs 8 in the extension of the first housings 55 is advantageous in several ways: it allows great rigidity of the guide studs 8 and therefore good precision of the guidance, it is possible to house in the guide stud 8 the supply valve of the actuator 56 so that the guide stud 8 ensures mechanical protection of said valve.
[0121] However, the guide studs 8 may have another shape, such as a half-tube, a solid cylinder, a half-cylinder, have a polygonal section, or be arranged elsewhere than in the extension of the first housings 55.
[0122] The number of guide pins 8 may be less than or more than four.
[0123] It is also possible to provide translational guidance on the one hand (for example two cylindrical surfaces providing a sliding pivot connection between the actuator-carrying ring 54 and the stator 2) and torque transfer on the other hand (a key for example).
[0124] The stator 2 can be fixed to the actuators by means other than screws and for example by fixing by magnetism, adhesive, pinning, etc.
[0125] When at least part of the wheel 103 and the rotor 3 are manufactured in a single piece, for example by casting or additive manufacturing, the integration of the rotor 3 in the wheel is improved, which eliminates the need to use means for fixing the rotor to the rim. It is therefore possible to obtain a simpler, more compact and lighter structure than that of conventional braked wheels. However, the rotor 3 can alternatively be attached to the wheel. The aluminum used here can be replaced in whole or in part by any material having physical properties compatible with the intended application and for example steel, copper, or magnesium.
[0126] The 63 screws can be replaced by any component that can perform the same functions.
[0127] The invention can be used on any type of vehicle, air, land or amphibious.
[0128] 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. Magnetic braking device (1) comprising a stator (2) and a rotor (3), one of the stator and the rotor comprising a first series of magnets (10.1) defining a main surface (2.1) which extends radially and which is turned towards the other of the stator and the rotor to emit between said stator and said rotor an axial magnetic flux, and one of the stator and the rotor comprising a second series of magnets (10.2) defining a second main surface (2.2) which extends axially to be able to receive or be engaged in the other of the stator and the rotor (3) to emit between said stator and said rotor a radial magnetic flux, characterized in that the first series of magnets comprises alternately at least first magnets (11.1, 11.1', 13.1) and second magnets (12.1, 12.1', 14.1) having a magnetization vector perpendicular to the first main surface, the magnetization vector of these first magnets and of these second magnets respectively exiting and entering the first main surface, and in that the second series of magnets comprises alternately at least first magnets (11.2, 11.2', 13.2) and second magnets (12.2, 12.2', 14.2) having a magnetization vector perpendicular to the second main surface, the magnetization vector of these first magnets and these second magnets respectively exiting and re-entering the second main surface, the first series of magnets and the second series of magnets being angularly offset from each other so that each first magnet and second magnet of the first series of magnets extends respectively, along a radial plane, opposite a second magnet and a first magnet of the second series of magnets.
2. Magnetic braking device (1) according to claim 1, wherein one of the stator (2) and the rotor (3) comprises the first series of magnets (10.1) and the second series of magnets (10.2).
3. Magnetic braking device (1) according to claim 2, wherein the stator (2) comprises the first series of magnets (10.1) and the second series of magnets (10.2).
4. Magnetic braking device (1) according to any one of the preceding claims, wherein the magnets of the first series of magnets (10.1) and the magnets of the second series of magnets (10.2) are arranged in a Halbach pattern.
5. Magnetic braking device (1) according to any one of the preceding claims, comprising at least one actuator (7) arranged to move the rotor (3) and the stator (2) relatively to each other along the axis of rotation of the rotor between a position of free rotation of the rotor and a braking position of the rotor.
6. Braked vehicle wheel (103), rotatably mounted on an axle (102) and equipped with a magnetic braking device (1) according to any one of the preceding claims, the rotor (3) and the stator (2) being respectively integral in rotation with the wheel and the axle.
7. Aircraft landing gear (101) comprising at least one wheel (103) according to claim 6.
8. Aircraft (100) comprising at least one landing gear (101) according to claim 7.