Running gear comprising a wheel and a tachometer connected to the wheel via a magnetic coupling device

Abstract

A running gear for a vehicle (1), comprising an axle (5, 5', 5''), a wheel (10, 10', 10'') rotatably mounted on the axle, and a tachometer (20, 20', 20'') mounted inside the axle, the tachometer comprising a stator (23, 23', 23'') that is fixed relative to the axle and a rotor (24, 24', 24'') that is rotationally coupled to the wheel by means of a magnetic coupling device (30, 30', 40, 40').

Description

[0001] Description

[0002] The present invention relates to the measurement of a rotational speed of a wheel and more particularly a rolling stock comprising a wheel and a tachometer connected to the wheel via a magnetic coupling device.

[0003] BACKGROUND OF THE INVENTION

[0004] An aircraft landing gear is typically equipped with tachometers to continuously measure the rotational speed of the braked wheels. These measured speeds provide essential data for the anti-slip and anti-lock braking systems. Therefore, the accuracy and reliability of tachometers are critical measuring instruments.

[0005] An aircraft wheel is typically mounted to rotate on a tubular axle carrying a wheel braking device. The axle has a free end inside which is housed a tachometer comprising a fixed part attached to the axle and a rotating part driven by the wheel. The fixed part generally includes a sensor to generate information about the wheel's rotational speed.

[0006] In general, the rotating part is guided in rotation relative to the fixed part by means of bearings and has a free end connected in rotation to a wheel guard via a mechanical coupling device to ensure the rotational drive of the rotating part by the wheel.

[0007] Misalignment of the protective cover with respect to the moving part of the tachometer results in the transmission of parasitic mechanical forces to the tachometer which tend to cause premature wear of the tachometer bearings and errors in measuring wheel speed.

[0008] OBJECT OF THE INVENTION The invention therefore aims to provide a running gear that at least partially overcomes the aforementioned drawback.

[0009] SUMMARY OF THE INVENTION

[0010] For this purpose, a running gear is proposed comprising an axle, a wheel mounted for rotation on the axle, and a tachometer mounted inside the axle, the tachometer comprising a stator fixed with respect to the axle and a rotor linked for rotation to the wheel by means of a magnetic coupling device.

[0011] The magnetic coupling device allows the transmission, without contact, of a driving torque delivered by the wheel to the rotor of the tachometer and therefore to: - adapt to the misalignment of said wheel with respect to said rotor without risking the transmission of parasitic mechanical forces to the tachometer which in particular increase the life of the bearings through which the rotor of the tachometer turns, and therefore reduce the maintenance requirements;

[0012] - limit the transmission of wheel vibration to the tachometer which could affect speed measurement at low speeds;

[0013] - to facilitate assembly and optimize the time required for its maintenance; and

[0014] - limit internal friction which can lead to speed measurement errors and premature wear of the tachometer bearings.

[0015] In particular, the magnetic coupling device includes first magnets and second magnets which are rotationally linked respectively to the wheel and rotor of the tachometer and which respectively delimit a first main surface and a second main surface separated from each other by an air gap and through which the first magnets and the second magnets respectively emit a first magnetic flux and a second magnetic flux interacting with each other.

[0016] According to a particular embodiment of the invention, the first magnetic flux and the second magnetic flux are axial magnetic fluxes.

[0017] According to another particular embodiment of the invention, the first magnetic flux and the second magnetic flux are radial magnetic fluxes.

[0018] According to another particular embodiment, the magnetic coupling device comprises a first rotor and a second rotor, each having a central axis substantially coinciding with a longitudinal axis of the axle, and which are respectively rotationally linked to the tachometer rotor and the wheel via mechanical coupling devices, the first rotor and the second rotor carrying the first magnets and the second magnets respectively.

[0019] In particular, the second rotor is rotationally linked to a wheel cover which is attached to the wheel.

[0020] According to another particular embodiment, the first magnets are carried by the tachometer rotor, and the second magnets are carried by a wheel cover which is attached to the wheel.

[0021] According to another particular embodiment of the invention, the running gear further comprises a magnetic stabilization device comprising a first magnet and a second magnet which are respectively fixed with respect to the wheel cover and the stator and which respectively delimit a first main surface and a second main surface separated from each other by an air gap and through which the first magnet and the second magnet respectively emit a first magnetic induction flux and a second magnetic induction flux interacting with each other to generate a repulsive force tending to limit a rapprochement between the wheel cover and the stator.

[0022] In particular, the first main surface and the second main surface of the magnetic stabilization device extend parallel to each other and define the same magnetic pole for the first magnet and the second magnet of said magnetic stabilization device.

[0023] In particular, the first magnet of the magnetic stabilization device has an external face of frustoconical shape and the second magnet of the magnetic stabilization device has an internal face of frustoconical shape, the internal face and the external face respectively delimiting the first main surface and the second main surface of said magnetic stabilization device.

[0024] According to another particular embodiment, the first magnets and the second magnets of the magnetic coupling device form Halbach lattices.

[0025] According to another particular embodiment, the first magnets and the second magnets of the magnetic coupling device are arranged so as to present an alternation of north-south type magnetic poles.

[0026] The invention also relates to an aircraft landing gear comprising an end with such a running gear.

[0027] The invention also relates to an aircraft comprising at least one such landing gear.

[0028] BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention will be better understood in the light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying drawings, among which: [Fig. 1] Figure 1 is a simplified view of an aircraft comprising main landing gear having one end equipped with a running gear according to the invention;

[0030] [Fig. 2A] Figure 2A is an axial cross-sectional view of a running gear, according to a first embodiment of the invention, of the aircraft illustrated in Figure 1;

[0031] [Fig. 2B] Figure 2B is a view analogous to Figure 2A representing a variant of the running gear illustrated in Figure 2A;

[0032] [Fig. 3A] Figure 3A is an axial cross-sectional view of a running gear, according to a second embodiment of the invention, of the aircraft illustrated in Figure 1;

[0033] [Fig. 3B] Figure 3B is a view analogous to Figure 3A representing a variant of the running gear illustrated in Figure 3A.

[0034] DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 1, the invention is described in application to an aircraft 1 comprising two main landers 2. Each of the main landers 2 has a leg 3 having a first end articulated to a structure 4 of the aircraft 1 and, opposite, a second end provided with a tubular shaft or axle 5 carrying wheels 10 rotating about a longitudinal axis X of the axle 5. The main landers 2 are here of the retractable type, but the invention is applicable to fixed landers, or even to another type of vehicle such as a land vehicle.

[0035] The following description relates to one of the wheels 10 of the aircraft, the wheels 10 being identical here but may also be different.

[0036] Referring to Figure 2A, the wheel 10 comprises a hub 11 pivotally received on the axle 5 by means of bearings 12, and a disc 13 connecting the hub 11 to an annular rim (not shown) on which a tire is mounted. The hub 11 has an end face carrying a wheel cover 14 which defines a cavity 14.1 into which a free end of the axle 5 is received, extending axially outward from said hub 11. The wheel cover 14 includes a flange 14.2 fixed to the end face of the hub 11 by means of screws 15 such that said wheel cover 14 is fixed relative to said hub 11 and therefore to the wheel 10.

[0037] The free end of the axle 5 is fitted with a cap 6 substantially bell-shaped. The cap 6 comprises a circular base 6.1 extending perpendicularly to the X-axis to form a bottom, and a skirt 6.2 extending from a periphery of the base 6.1 to form a tubular side wall having a central axis substantially coinciding with the X-axis. The skirt 6.2 has an external surface cooperating with an internal surface of the axle 5, and has a free end provided with a collar 6.3 forming a stop against the insertion of the cap 6 into the axle 5. The cap 6 is fixed to the axle 5 by means of bolts 7 passing radially through the skirt 6.2 and the free end of the axle 5, such that the cap 6 is fixed relative to the axle 5.

[0038] It should be noted that the base 6.1 and the skirt 6.2 of the plug 6 together define a cavity 6.4 opening outside the axle 5 to receive, as will be seen later, a magnetic coupling device 30 with axial flux.

[0039] The axle 5 receives a tachometer 20, generally cylindrical in shape, to measure the angular speed of rotation of the wheel 10 around the axis X. The tachometer 20 comprises a main body 21 which extends inside the axle 5, set back from the free end of said axle 5, and which has a longitudinal axis substantially coinciding with the axis X. The body 21 extends outside the cavity 6.4 delimited by the plug 6 and has an end fixed to the base 6.1 of said plug 6 by means of two screws 22 so that the body 21 is stationary with respect to the axle 5. It is understood that the base 6.1 of the plug 6 forms a mounting plate for the tachometer 20.

[0040] In a manner known per se, the tachometer 20 further comprises a stator 23 extending fixedly inside the body 21 and a rotor 24 rotating about the X axis. The stator 23 includes a non-contact sensor 23.1 having a measuring cell adapted to cooperate axially (as shown in Figure 2A) or radially with a plurality of targets 24.1 carried by the rotor 24 to generate a signal representative of a speed of said rotor 24.

[0041] The rotor 24 has an output shaft 24.2 extending substantially along the X axis, projecting from the body 21 of the tachometer 20. The output shaft 24.2 is connected to the wheel cover 14 by means of the axial flux magnetic coupling device 30.

[0042] The magnetic coupling device 30 comprises a first rotor 31, or driven rotor, and a second rotor 32, or drive rotor. The first rotor 31 and the second rotor 32 each have a central axis X31, X32 substantially coinciding with the longitudinal X-axis of the axle 5.

[0043] The first rotor 31 comprises a first disk 31.1 which has a primary face bearing first permanent magnets 31.2 and, opposite it, a secondary face from which a first connecting shaft 31.3 extends coaxially. The first disk 31.1 and the first connecting shaft 31.3 each have a central axis coinciding with the X31 axis. The first magnets 31.2 form a first annular Halbach array and have a front face delimiting a principal surface 31.4 of the first rotor 31 through which said first magnets 31.2 emit a first axial magnetic flux. The first Halbach array has a central axis substantially coinciding with the X31 axis of the first rotor 31. The first magnets 31.2 here include primary magnets which have magnetization vectors substantially parallel to the central axis X31 of the first rotor 31 and which are separated in pairs by secondary magnets having magnetization vectors substantially perpendicular to those of the primary magnets.

[0044] Similarly, the second rotor 32 comprises a second disk 32.1 which has a primary face bearing permanent second magnets 32.2 and, opposite it, a secondary face from which a second connecting shaft 32.3 extends coaxially. The second disk 32.1 and the second connecting shaft 32.3 each have a central axis coinciding with the X32 axis. The second magnets 32.2 form a second annular Halbach array and have a front face delimiting a principal surface 32.4 of the second rotor 32 through which said second magnets 32.2 emit a second axial magnetic flux. The second Halbach array has a central axis substantially coinciding with the X32 axis of the second rotor 32. The second magnets 32.2 here include primary magnets which have magnetization vectors substantially parallel to the central axis X32 of the second rotor 32 and which are separated in pairs by secondary magnets having magnetization vectors substantially perpendicular to those of the primary magnets.

[0045] It should be noted that the first rotor 31 and the second rotor 32 are identical here.

[0046] The connecting shaft 31.3 of the first rotor 31 is linked to the output shaft 24.2 of the tachometer 20 by means of a first mechanical coupling system (not shown) arranged so that a rotation of the first rotor 31 around the X axis causes a rotation of the output shaft 24.2 of the tachometer 20 around said X axis. It is understood that the output shaft 24.2 of the tachometer 20 and the first rotor 31 of the magnetic coupling device 30 are rotationally linked.

[0047] The connecting shaft 32.3 of the second rotor 32 is linked to the wheel cover 14 by means of a second mechanical coupling system (not shown) arranged so that a rotation of the wheel cover 14 around the X axis causes a rotation of the second rotor 32 around said X axis. It is understood that the wheel 10 and the second rotor 32 of the magnetic coupling device 30 are rotationally linked.

[0048] The first main surface 31.4 of the first rotor 31 and the second main surface 32.4 of the second rotor 32 extend axially opposite each other and are separated by a predetermined air gap e so that the first and second magnetic fluxes emitted by the first and second magnets 31.2, 32.2 interact sufficiently so that a rotation of the second rotor 32 around the X-axis causes a rotation of the first rotor 31 around said X-axis. The first rotor 31 and the second rotor 32 are thus linked in rotation, the magnetic coupling device 30 allowing the transmission, without contact, of a rotational drive torque.

[0049] It is understood that a rotation of the wheel 10, and therefore of the wheel cover 14 around the X axis, causes, via the magnetic coupling device 30, a rotation of the output shaft 24.2 of the tachometer 20. The magnetic coupling device 30 makes it possible to adapt to the misalignment of the wheel cover 14 with respect to the output shaft 24.2 of the tachometer 20 without risking the transmission of parasitic mechanical forces to the tachometer 20. It also makes it easier to assemble the unit and therefore to optimize the time required for its maintenance.

[0050] The Halbach lattice arrangement of the first and second magnets 31.2, 32.2 optimizes the magnetic flux emitted by said first and second magnets 31.2, 32.2 and therefore optimizes the torque transmitted between the first and second rotors 31, 32.

[0051] The Halbach lattice arrangement of the first and second magnets 31.2, 32.2 also makes it possible to reduce the leakage of the magnetic flux emitted by said first and second magnets 31.2, 32.2 and thus to optimize the thickness of the first and second disks 31.1, 32.1 in order to limit their mass.

[0052] It should be noted that the assembly comprising the axle 5 equipped with the cap 6, the wheel 10 equipped with the wheel cover 14, the tachometer 20 and the magnetic coupling device 30 forms a running gear according to a first embodiment of the invention.

[0053] Figure 2B illustrates a radial flux magnetic coupling device 30' which is simply a variant of the axial flux magnetic coupling device 30.

[0054] The magnetic coupling device 30' comprises a first rotor 31' or driven rotor, and a second rotor 32' or drive rotor. The first rotor 31' and the second rotor 32' each have a central axis X31', X32' substantially coinciding with the longitudinal X axis of the axle 5.

[0055] The first rotor 31' comprises a ring 31.1' and a first connecting shaft 31.3' linked by a web 31.5' to one end of the ring 31.1'. The ring 31.1' and the first connecting shaft 31.3' extend on either side of the web 31.5' and each have a central axis coinciding with the X-axis 31'. The ring 31.1' has an inner rim carrying first permanent magnets 31.2'. The first magnets 31.2' form a first annular Halbach array and have an outer face defining a principal surface 31.4' of the first rotor 31' through which said first magnets 31.2' emit a first radial magnetic flux.

[0056] The second rotor 32' comprises a second connecting shaft 32.3' having one end carrying second permanent magnets 32.2' extending around the second connecting shaft 32.3'. The second magnets 32.2' form a second annular Halbach grating, delimiting a main surface 32.4' of the second rotor 32 through which said first magnets 32.3 emit a second radial magnetic flux.

[0057] The connecting shaft 31.3' of the first rotor 31' is linked to the output shaft 24.2 of the tachometer 20 by means of a first mechanical coupling system (not shown) arranged so that a rotation of the first rotor 31' around the X axis causes a rotation of the output shaft 24.2 around said X axis. It is understood that the output shaft 24.2 of the tachometer 20 and the first rotor 31' of the magnetic coupling device 30' are rotationally linked.

[0058] The connecting shaft 32.3' of the second rotor 32' is linked to the wheel cover 14 by means of a second mechanical coupling system (not shown) arranged so that a rotation of the wheel cover 14 around the X axis causes a rotation of the second rotor 32' around said X axis. It is understood that the wheel 10 and the second rotor 32' of the magnetic coupling device 30' are rotationally linked.

[0059] The end of the connecting shaft 32.3' of the second rotor 32' extends inside the ring 31.1' of the first rotor 31' such that the first main surface 31.4' of the first rotor 31' and the second main surface 32.4' of the second rotor 32' extend radially opposite each other and are separated by a predetermined air gap e' so that the first and second magnetic fluxes emitted by the first and second magnets 31.2', 32.2' interact sufficiently so that a rotation of the second rotor 32' around the X-axis causes a rotation of the first rotor 31' around said X-axis. The first rotor 31' and the second rotor 32' are thus rotationally linked, the magnetic coupling device 30' allowing the transmission, without contact, of a rotational drive torque.

[0060] It is understood that a rotation of the wheel 10, and therefore of the wheel cover 14 around the X axis, causes, via the magnetic coupling device 30', a rotation of the output shaft 24.2 of the tachometer 20. The magnetic coupling device 30' allows, like the magnetic coupling device 30, to adapt to the misalignment of the wheel cover 14 with respect to the output shaft 24.2 of the tachometer 20 without risking the transmission of parasitic mechanical forces to the tachometer 20. It also makes it easier to assemble the unit and therefore to optimize the time required for its maintenance.

[0061] Figure 3A illustrates a running gear according to a second embodiment of the invention, comprising an axle 5', a wheel 10' rotating about a longitudinal axis X' of the axle 5' and equipped with a wheel cover 14', and a tachometer 20'.

[0062] The wheel 10' comprises a hub 11' pivotally received on the axle 5' by means of bearings 12', and a disc 13' connecting the hub 11' to an annular rim (not shown) on which a tire is mounted. The hub 11' has an end face onto which a wheel cover 14' is attached, defining a cavity 14.1' that receives a free end of the axle 5' extending axially beyond the hub 11'. The wheel cover 14' is fixed to the hub 11' by means of a clamp 15' such that the wheel cover 14' is fixed relative to the hub 11' and therefore to the wheel 10'.

[0063] The axle 5' receives a tachometer 20', generally cylindrical in shape, to measure the angular speed of rotation of the wheel 10' around the axis X'. The tachometer 20' comprises a main body 21' which extends inside the axle 5' and which has a longitudinal axis substantially coinciding with the axis X'.

[0064] In a manner known per se, the tachometer 20' further comprises a stator 23' and a rotor 24' rotating inside the stator 23' along the X' axis by means of bearings 22'. The stator 23' includes a non-contact sensor 23.1' having a measuring cell adapted to cooperate, here axially, with a plurality of targets 24.1' carried by the rotor 24' to generate a signal representative of a speed of said rotor 24'.

[0065] The rotor 24' has an end face 24.2' extending substantially perpendicularly to the X' axis, inside the stator 23'. The end face 24.2' of the rotor 24' is connected to a central face 14.2' of the wheel cover 14' by means of the axial flux magnetic coupling device 40. The central face 14.2' of the wheel cover 14' and the end face 24.2' of the rotor 24' of the tachometer 20' each have a central axis X14', X24' substantially coinciding with the longitudinal X' axis of the axle 5' and extend axially opposite each other.

[0066] The magnetic coupling device 40 includes first permanent magnets 41 carried by the end face 24.2' of the rotor 24' of the tachometer 20', and second permanent magnets 42 carried by the central face 14.2' of the wheel cover 14' and extending axially opposite the first magnets 41.

[0067] The first 41 magnets here include primary magnets which have magnetization vectors substantially parallel to the X-axis 24 central of the rotor 24' of the tachometer 20' and directed towards the second magnets 42, and which are separated two by two by secondary magnets having magnetization vectors substantially parallel and in the opposite direction to those of the primary magnets. It is understood that the alternation of the magnetic poles of the primary and secondary magnets is of the north-south (NS) type.

[0068] The first magnets 41 have a front face delimiting respectively a first main surface 41.4 of the magnetic coupling device 40 through which said first magnets 41 emit a first axial magnetic flux.

[0069] Similarly, the second magnets 42 here include primary magnets which have magnetization vectors substantially parallel to the X-axis 14central of the wheel cover 14' and directed towards the first magnets 41, which are separated in pairs by secondary magnets having magnetization vectors substantially parallel and in the opposite direction to those of the primary magnets. It is understood that the alternation of the magnetic poles of the primary and secondary magnets is of the north-south (NS) type.

[0070] The second magnets 42 have a front face delimiting respectively a second main surface 42.4 of the magnetic coupling device 40 through which said second magnets 42 emit a second axial magnetic flux.

[0071] The first main surface 41.4 and the second main surface 42.4 of the magnetic coupling device 40 extend axially opposite each other and are separated by a predetermined air gap E so that the first and second magnetic fluxes emitted by the first and second magnets 41.2, 42.2 interact sufficiently for a rotation of the wheel cover 14' around the X' axis to cause a rotation of the tachometer rotor 24' 20' around said X' axis. The wheel cover 14' and the tachometer rotor 24' 20' are thus rotationally linked, the magnetic coupling device 40 enabling the transmission, without contact, of a rotational drive torque.

[0072] It is understood that a rotation of the wheel 10', and therefore of the wheel cover 14', around the X' axis causes, via the magnetic coupling device 40, a rotation of the rotor 24' of the tachometer 20'. The magnetic coupling device 40 allows adaptation to the misalignment of the wheel cover 14' with respect to the rotor 24' of the tachometer 20' without risking the transmission of parasitic mechanical forces to said tachometer 20' and in particular to its bearings 22'. It also facilitates the assembly of the unit and thus optimizes the time required for its maintenance.

[0073] It should also be noted that the magnetic coupling device 40 is, unlike the magnetic coupling devices 30, 30', integrated into the tachometer 20', which helps to limit its size and therefore its mass.

[0074] Figure 3B illustrates a variant of the running gear shown in Figure 3A, comprising a 5'' axle, a 10'' wheel rotating about a longitudinal X'' axis of the 5'' axle and fitted with a 14'' wheel cover, and a 20'' tachometer.

[0075] The wheel 10'' comprises a hub 11'' received by pivoting on the axle 5'' by means of bearings 12'', a disc 13'' connecting the hub 11'' to an annular rim (not shown) on which a tire is mounted. The hub 11'' has an end face onto which is attached a wheel cover 14'' which delimits a cavity 14.1'' receiving a free end of the axle 5'' extending axially in projection from said hub 11''. The wheel cover 14'' is fixed to the hub 11'' by means of a clamp 15'' so that said wheel cover 14'' is fixed with respect to said hub 11'' and therefore to the wheel 10''. The axle 5'' receives a tachometer 20'', of generally cylindrical shape, to measure the angular speed of rotation of the wheel 10'' around the axis X''.The tachometer 20'' comprises a main body 21'' which extends inside the axle 5'' and has a longitudinal axis substantially coincident with the X'' axis.

[0076] In a manner known per se, the tachometer 20'' further comprises a stator 23'' and a rotor 24'' rotating inside the stator 23'' along the X' axis by means of bearings 22''. The stator 23'' includes a non-contact sensor 23.1'' having a measuring cell adapted to cooperate, here radially, with a plurality of targets 24.1'' carried by the rotor 24'' to generate a signal representative of a speed of said rotor 24''.

[0077] The rotor 24'' has an inner perimeter 24.2'' extending substantially around the axis X'', inside the stator 23''. The inner perimeter 24.2'' of the rotor 24'' is connected to an outer perimeter 14.2'' of a central pin of the wheel cover 14'' by means of the radial flux magnetic coupling device 40'. The outer perimeter 14.2'' of the central pin of the wheel cover 14'' and the inner perimeter 24.2'' of the rotor 24'' of the tachometer 20'' each have a central axis X14'', X24'' substantially coincident with the longitudinal axis X'' of the axle 5'' and extend axially opposite each other.

[0078] The magnetic coupling device 40' comprises first permanent magnets 41' carried by the inner perimeter 24.2'' of the rotor 24'' of the tachometer 20'', and second permanent magnets 42' carried by the outer perimeter 14.2'' of the central pin of the wheel cover 14'' and extending axially opposite the first magnets 41''.

[0079] The first 41' magnets here include primary magnets which have magnetization vectors substantially parallel to the X-axis 24 ' ' central of the rotor 24 ' ' of the tachometer 20 ' ' and directed towards the second magnets 42', and which are separated in pairs by secondary magnets having magnetization vectors substantially parallel and in the opposite direction to those of the primary magnets. It is understood that the alternation of the magnetic poles of the primary and secondary magnets is of the north-south (NS) type.

[0080] The first magnets 41' have an inner face delimiting respectively a first main surface 41.4' of the magnetic coupling device 40' through which said first magnets 41' emit a first axial magnetic flux.

[0081] Similarly, the second magnets 42' here include primary magnets which have magnetization vectors substantially parallel to the X-axis 14 ' ' central of the wheel cover 14' ' and directed towards the first magnets 41', and which are separated in pairs by secondary magnets having magnetization vectors substantially parallel and in the opposite direction to those of the primary magnets. It is understood that the alternation of the magnetic poles of the primary and secondary magnets is of the north-south (NS) type.

[0082] The second magnets 42' have an inner face delimiting respectively a second main surface 42.4' of the magnetic coupling device 40' through which said second magnets 42' emit a second axial magnetic flux.

[0083] The first main surface 41.4' and the second main surface 42.4' of the magnetic coupling device 40' extend radially opposite each other and are separated by a predetermined air gap E' so that the first and second magnetic fluxes emitted by the first and second magnets 41.2', 42.2' interact sufficiently so that a rotation of the wheel cover 14'' around the X'' axis causes a rotation of the tachometer rotor 24'' around said X'' axis. The wheel cover 14'' and the tachometer rotor 24'' are thus rotationally linked, the magnetic coupling device 40' allowing the transmission, without contact, of a rotational driving torque.

[0084] It is understood that a rotation of the wheel 10'', and therefore of the wheel cover 14'', around the X' axis, causes, via the magnetic coupling device 40'', a rotation of the rotor 24'' of the tachometer 20''. The magnetic coupling device 40'', like the magnetic coupling device 40'', allows adaptation to the misalignment of the wheel cover 14'' with respect to the rotor 24'' of the tachometer 20'' without risking the transmission of parasitic mechanical forces to said tachometer 20'', and in particular to its bearings 22''. It also facilitates the assembly of the unit and thus optimizes the time required for its maintenance.

[0085] It should also be noted that the magnetic coupling device 40' is, like the magnetic coupling device 40, integrated into the tachometer 20', which helps to limit its size and therefore its mass.

[0086] Optionally, the central pin of the wheel cover 14'' and the rotor 24'' of the tachometer 20'' may be fitted with a magnetic stabilization device 50'' arranged to limit the relative vibrations between said central pin and said rotor 24'' which may affect the speed measurement by the tachometer 20''.

[0087] With reference to Figure 3B, the stabilization device 50'' comprises a first annular magnet 51'' carried by a free end of the central pin of the wheel cover 14'', and a second annular magnet 52'' carried by an internal radial end of the stator 23'' of the tachometer 20''. The first magnet 51'' and the second magnet 52'' each have a central axis substantially coincident with the longitudinal X'' axis of the axle 5'' and are respectively fixed with respect to the wheel cover 14'' and the stator 23''. The first magnet 51'' and the second magnet 52'' of the stabilizing device 50'' are axially offset with respect to the first magnets 41' and the second magnets 42' of the magnetic coupling device 40'.More specifically, the first magnet 51'' and the second magnet 52'' of the stabilizing device 50'' are, along the longitudinal axis X'' of the axle 5'', located at a non-zero distance from the first magnets 41' and the second magnets 42' of the magnetic coupling device 40', along the longitudinal axis X'' of the axle 5''.

[0088] The first magnet 51'' has an external face, of frustoconical shape, which is turned towards the second magnet 52'' and which delimits a first main surface 50.1'' of the magnetic stabilization device 50'' defining a north pole of the first magnet 51'' and by which said first magnet 51'' emits a first magnetic induction flux having a non-zero axial component and a non-zero radial component.

[0089] The second magnet 52'' has an inner face, of frustoconical shape, which is turned towards the first magnet 51'' and which delimits a second main surface 50.2'' of the magnetic stabilization device 50'' defining a north pole of the second magnet 52'' by which said second magnet 52'' emits a second magnetic induction flux having a non-zero axial component and a non-zero radial component.

[0090] We understand that the north poles of the first and second magnets 51'', 52'' face each other and therefore repel each other.

[0091] The first main surface 50.1'' and the second main surface 50.2'' extend substantially parallel to each other and are separated by an air gap so that the first and second magnetic induction fluxes emitted by the first and second magnets 51'', 52'' interact sufficiently to generate a repulsive force tending to limit any approach between the central pin of the wheel cover 14'' and the stator 23'', and thus to circumscribe any misalignment (axial and / or radial) between the first magnets 41' and the second magnets 42' of the magnetic coupling device 40' along the X'' axis, particularly in service.

[0092] It is understood that the stabilization device 50' ' makes it possible in particular to limit the variation of the air gap E' separating the first main surface 41.4' ' of the first magnets 41' and the second main surface 42.4' ' of the second magnets 42', and therefore to preserve the bearings 22'.

[0093] In particular, the stator 23'' is fixed relative to the axle 5" and the forces due to the variation of the air gap E' are transmitted to the stator 23" mainly through the first magnet 51" and the second magnet 52" of the stabilizing device 50" and not through the first magnets 41' and the second magnets 42' of the magnetic coupling device 40', so that the bearings 22" are under little stress.

[0094] Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0095] Although the magnetic coupling device 30, 30', 40, 40' is here axial flux or radial flux, it can be mixed flux, i.e. axial and radial flux, depending on the drive torque to be transmitted.

[0096] Although the first magnets 31.2, 31.2' and the second magnets 32.2, 32.2' of the magnetic coupling devices 30, 30' form Halbach lattices, they can also adopt an alternation of magnetic poles of the north-south type.

[0097] Although the first magnets 41, 41' and the second magnets 42, 42' of the magnetic coupling devices 40, 40' adopt an alternation of magnetic poles of the north-south type, they can also form Halbach lattices.

[0098] Although the magnetic coupling device 30, 30', 40, 40' here incorporates permanent magnets, it can also implement any other magnetically driven topology (variable reluctance, eddy currents, hysteresis...).

[0099] Although the first and second main surfaces 50.1' ', 50.2' ' of the first and second magnets 51' ', 52' ' of the magnetic stabilization device 50' ' here define north poles of the first and second magnets 51' ', 52' ', they can also define south poles of said first and second magnets 51' ', 52' '.

[0100] Although the 50' ' magnetic stabilization device is here associated with a 40' radial flux magnetic coupling device, it can also be associated with a 40 axial flux magnetic coupling device.

[0101] Although the magnetic coupling device 30, 30', 40, 40' is here axial flux or radial flux, it can also combine axial flux and radial flux.

Claims

DEMANDS 1. Vehicle running gear (1), comprising an axle (5, 5', 5''), a wheel (10, 10', 10'') mounted for rotation on the axle, and a tachometer (20, 20', 20'') mounted inside the axle, the tachometer comprising a stator (23, 23', 23'') fixed opposite the axle and a rotor (24, 24', 24'') connected for rotation to the wheel by means of a magnetic coupling device (30, 30', 40, 40').

2. A running gear according to claim 1, wherein the magnetic coupling device (30, 30', 40, 40') comprises first magnets (31.2, 31.2', 41, 41') and second magnets (32.2, 32.2', 42, 42') which are rotationally linked respectively to the wheel and the rotor of the tachometer and which respectively delimit a first principal surface (31.4, 31.4', 41.4, 41.4') and a second principal surface (32.4, 32.4', 42.4, 42.4') separated from each other by an air gap (e, e', E, E') and through which the The first magnets and the second magnets emit, respectively, a first magnetic flux and a second magnetic flux that interact with each other.

3. A rolling stock according to claim 2, wherein the first magnetic flux and the second magnetic flux are axial magnetic fluxes.

4. Rolling stock according to claim 2, wherein the first magnetic flux and the second magnetic flux are radial magnetic fluxes.

5. Rolling stock according to any one of claims 2 to 4, wherein the magnetic coupling device (30, 30') comprises a first rotor (31, 31') and a second rotor (32, 32') which each have a central axis (X31, X31', X32, X32') substantially coinciding with a longitudinal axis (X) of the axle and which are respectively rotationally linked to the rotor (24) of the tachometer (20, 20') and to the wheel (10, 10') via mechanical coupling devices, the first rotor and the second rotor carrying respectively the first magnets (31.2, 31.2') and the second magnets (32.2, 32.2').

6. Rolling stock according to any one of claims 2 to 4, wherein the first magnets (41, 41') are carried by the rotor (24', 24'') of the tachometer (20', 20''), and the second magnets (42, 42') are carried by a wheel cover (14', 14'') which is fixed to the wheel (10', 10').

7. Rolling stock according to claim 6, further comprising a magnetic stabilization device (50'') having a first magnet (51'') and a second magnet (52'') which are respectively fixed with respect to the wheel cover (14'') and the stator (23'') and which respectively delimit a first main surface (50.1'') and a second main surface (50.2'') separated from each other by an air gap and through which the first magnets and the second magnets respectively emit a first magnetic induction flux and a second magnetic induction flux interacting with each other to generate a repulsive force tending to limit a rapprochement between the wheel cover and the stator.

8. Rolling stock according to claim 7, in which the first main surface (50.1'') and the second main surface (50.2'') of the magnetic stabilization device (50'') extend parallel to each other and define the same magnetic pole for the first magnet (51'') and the second magnet (52'') of said magnetic stabilization device (50'').

9. Rolling stock according to claim 8, wherein the first magnet (51'') of the magnetic stabilization device (50'') has an external face of frustoconical shape and the second magnet (52'') of the magnetic stabilization device (50'') has an internal face of frustoconical shape, the internal face and the external face respectively delimiting the first main surface (50.1'') and the second main surface (50.2'') of said magnetic stabilization device (50'').

10. Rolling stock according to any one of claims 2 to 9, in which the first magnets (31.2, 31.2') and the second magnets (32.2, 32.2') of the magnetic coupling device (30, 30') form Halbach lattices.

11. Rolling stock according to any one of claims 2 to 9, wherein the first magnets (41, 41') and the second magnets (42, 42') of the magnetic coupling device (40, 40') are arranged so as to present an alternation of magnetic poles of the north-south type.

12. Aircraft landing gear (2), comprising an end having a running gear according to any one of the preceding claims.

13. Aircraft (1) comprising at least one landing gear (2) according to claim 12.

Images