FR3148994A1 - Running gear for a vehicle comprising a wheel and a wheel drive device, aircraft landing gear and aircraft equipped with such running gear - Google Patents

Abstract

Running gear for a vehicle (1) comprising an axle support (5) in which an axle (6) is mounted so as to be movable in rotation, the axle comprising a first end on which a wheel (10) is fixedly mounted, and a second end, opposite the first end, connected to a drive device (100, 100', 100'') arranged to drive the axle in rotation. Aircraft landing gear (2) and aircraft (1) equipped with such a running gear. FIGURE OF THE ABSTRACT: Fig.2

Description

Running gear for a vehicle comprising a wheel and a wheel drive device, aircraft landing gear and aircraft equipped with such running gear

The present invention relates to the ground movement of a vehicle, and more particularly to a running gear comprising a wheel and a wheel drive device. The invention also relates to an aircraft landing gear and an aircraft equipped with such a running gear.

BACKGROUND OF THE INVENTION

In the field of aviation, it is now planned to equip aircraft with wheel rotation drive units to enable the aircraft to be moved on the ground without using its powertrains.

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.

However, in the case of electric vertical take-off and landing aircraft (eVTOL), the wheels are traditionally small (between 6 and 10 inches) so it is very difficult to integrate equipment such as a drive unit.

Furthermore, climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being or will be adopted by various states. In particular, an ambitious standard applies both to new types of aircraft as well as those currently in circulation requiring the implementation of technological solutions in order to make them compliant with current regulations. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change.

Technological research efforts have already made it possible to significantly improve the environmental performance of aircraft. All players in the sector are constantly working to improve energy efficiency. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental impacts with the aim of improving the energy efficiency of air transport.

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

This sustained research and development work covers new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and the lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

SUBJECT OF THE INVENTION

The invention results from this work and aims to propose a running gear for a vehicle making it possible to at least partially overcome the aforementioned drawback.

For this purpose, according to the invention, there is provided a running gear for a vehicle comprising an axle support in which an axle is mounted so as to be movable in rotation, the axle comprising a first end on which a wheel is fixedly mounted, and a second end, opposite the first end, connected to a drive device arranged to drive the axle in rotation.

The adoption of a drive axle and the integration of a drive device outside the wheel allows, for a predetermined wheel size, to optimize the space available inside the wheel which is generally occupied by wheel bearings and a structural interface with the wheel, and to be able to integrate equipment such as a tire pressure monitoring device, a wheel speed sensor, a parking brake, etc.

According to a particular embodiment of the invention, the wheel and the drive device extend axially on either side of the axle support.

According to a particular feature, the drive device comprises an electric motor.

Preferably, the electric motor is radial flux.

According to another particular characteristic of the invention, the drive device comprises a reducer, an output shaft of which is rotationally connected to the second end of the axle.

In particular, the reducer is a planetary reducer.

In particular, the reducer is a strain wave reducer.

In particular, the reducer is a multi-stage reducer.

The invention also relates to an aircraft landing gear comprising an end comprising such a running gear.

The invention further relates to an aircraft comprising at least one such landing gear.

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:

there is a simplified representation of an aircraft comprising main landing gears each equipped with a powered wheel;

there is an axial sectional view of one of the powered wheels of the aircraft illustrated in , according to a first embodiment of the invention;

there is a view of a first variant of the motorized wheel drive device illustrated in ;

there is a view of a second variant of the motorized wheel drive device illustrated in ;

there is an axial sectional view of a parking brake that can be fitted to the motorized wheels illustrated in Figures 2, 3 and 4;

there is a cross-sectional view of the parking brake shown in .

DETAILED DESCRIPTION OF THE INVENTION

In reference to the , the invention is described in application to an electric vertical take-off and landing (eVOTL ) aircraft 1. The aircraft 1 comprises two main landing gears 2 each comprising a leg 3 having an upper end fixed to a structure 4 of the aircraft and, on the opposite side, a lower end carrying a wheel 10. The landing gears 2 are here fixed but the invention is applicable to retractable type landing gears, or even to another type of aircraft or vehicle such as a land vehicle.

The lower end of leg 3 comprises, as shown in , a support 5 inside which is mounted a tubular axle 6 rotating about an axis X by means of a first bearing 7.1 and a second bearing 7.2.

The axle support 5 has a first end comprising a first bore 5.1 in which the first bearing 7.1 is received, and a second end, opposite the first end, comprising a second bore 5.2 in which the second bearing 7.2 is received. The first bearing 7.1 and the second bearing 7.2 comprise an outer ring respectively bearing against a bottom of the first bore 5.1 and a bottom of the second bore 5.2.

• un premier tronçon 6a, de forme cylindrique, s’étendant à l’intérieur du support d’essieu 5 et sur lequel sont montés le premier roulement 7.1 et le deuxième roulement 7.2 ;
• un deuxième tronçon 6b, de forme cylindrique, s’étendant en saillie axiale d’une première extrémité 5a du support d’essieu 5 et portant la roue 10 ; et
• un tronçon central 6c, de forme tronconique, ayant une grande base et une petite base reliées respectivement au premier tronçon 6a et au deuxième tronçon 6b.

Axle 6 includes:

• a first section 6a, of cylindrical shape, extending inside the axle support 5 and on which the first bearing 7.1 and the second bearing 7.2 are mounted;
• a second section 6b, of cylindrical shape, extending in axial projection from a first end 5a of the axle support 5 and carrying the wheel 10; and
• a central section 6c, of truncated cone shape, having a large base and a small base connected respectively to the first section 6a and to the second section 6b.

The large base of the central section 6c defines a shoulder against which an inner ring of the second bearing 7.2 bears, and a free end of the first section 6a receives a retaining nut 8 bearing against an inner ring of the first bearing 7.1 by means of a bearing spacer 9, so that the axle 6 is immobile in translation along the X axis with respect to the axle support 5.

The wheel 10 comprises a hub 11 mounted on a free end of the second section 6b of the axle 6, and a rim 12 comprising an annular portion 12a connected to the hub 11 by a web 12b, said hub 11 and said web 12b being bolted to each other.

In a manner known per se, each of the ends of the annular portion 12a of the rim 12 is shaped into a bead 13 for retaining a tire (not shown).

The hub 11 comprises an internal circumference which comprises splines cooperating with homologous splines arranged on the second section 6b of the axle 6 to ensure rotational coupling of the hub 11 with the axle 6 about the axis X. The second section 6b comprises a shoulder against which the hub 11 bears, and receives at its free end a nut 14 arranged to keep said hub 11 bearing against the shoulder and thus immobilize it axially. It is understood that the hub 11, and therefore the wheel 10, are fixed relative to the axle 6.

The wheel 10 is said to be “motorized”, that is to say equipped with a rotating drive device 100 intended to move the aircraft 1 without using its powertrains when it is on the ground.

The drive device 100 extends in axial projection from a second end 5b of the axle support 5, opposite the first end 5a, so that said drive device 100 and the wheel 10 each extend on either side of the axle support 5 and the leg 3.

The drive device 100 comprises a protective casing 101, of generally tubular shape, inside which extends a radial flux electric motor 110 and a two-stage reducer 120 connected to an output shaft 113 of the electric motor 110 to increase the drive torque delivered by said electric motor 110 to the wheel 10.

The casing 101 is made in two parts: it comprises a first part 101.1 which is fixed to the second end 5b of the axle support 5 via screws 102.1 and which delimits with said second end 5b a first annular space inside which the reducer 120 extends, and a second part 101.2 which is fixed to the first part 101.1 via screws 102.2 and which delimits with said first part 101.1 a second annular space inside which the electric motor 110 extends.

In a manner known per se, the electric motor 110 comprises a fixed element or stator 111, and a rotating mobile element or rotor 112, the stator 111 and the rotor 112 here each having a central axis coincident with the axis X of rotation of the wheel 10.

The stator 111 here has the form of a crown mounted fixed on an internal periphery of the second part 101.2 of the casing 101, and comprises a pack of sheets 111a forming a plurality of teeth which extend radially around the axis X and on which windings 111b are wound.

The rotor 112 here has the shape of a crown of a disk fixedly mounted on the output shaft 113 of the electric motor 110. The output shaft 113 is mounted to be mobile in rotation about the axis X by means of two bearings 114, one of which is received in a bore formed in the first part 101.1 of the casing 101 and the other in a bore formed in the second part 101.2 of the casing 101. The rotor 112 extends inside the stator 111 and comprises an external periphery provided with a series of magnets 112a capable of interacting with the windings 111b carried by said stator 111 to drive the rotor 112 and therefore the output shaft 113 in rotation.

The reducer 120 is a two-stage planetary reducer. Each of these stages comprises four satellites 121.1, 121.2 mounted in the same satellite carrier 122.1, 122.2, the satellites 121.1, 121.2 meshing simultaneously with an internal or planetary pinion 123.1, 123.2 and with an external crown 124 common to both stages.

Each of the planet carriers 122.1, 122.2 comprises two circular plates perpendicular to the X axis and connected by pads 125.1, 125.2 around which the satellites 121.1, 121.2 rotate by means of a bearing 126.1, 126.2 of axis X.

The sun gear 123.1 of the first stage is formed by a free end of the output shaft 113 of the electric motor 110, the free end comprising an external circumference provided with teeth distributed angularly in a regular manner around the axis X: the sun gear 123.1 here forms part of the output shaft 113. The planet carrier 122.1 of the first stage has an extension provided with external teeth forming the sun gear 123.2 of the second stage: the sun gear 123.2 of the second stage forms part of the planet carrier 122.1 of the first stage. The planet carrier 122.2 of the second stage has an extension which comprises external splines cooperating with internal splines arranged at the free end of the first section 6a of the axle 6 to ensure a rotational coupling of said planet carrier 122.2 with the axle 6 about the axis X. The toothed end of the output shaft 113 and the extension of the planet carrier 122.2 respectively form an input axis and an output axis of the reducer 120.

The outer ring 124 is constituted by an annular portion of the first part 101.1 of the casing 101, the annular portion comprising an internal toothing meshing with the satellites 121.1, 121.2 of each of the stages of the reducer 120: the outer ring 124 is part of the casing 101.

It should be noted that by combining several functions within the electric motor 110 and the reducer 120 in a single part, the drive device 100 is particularly compact and lightweight.

It is also understood that the adoption of a 6-wheel drive axle and the integration of a drive device 100 outside the wheel 10 make it possible to optimize the space available inside the wheel 10 and therefore to limit the size of the latter while being able to use this space for the integration of other equipment such as a tire pressure monitoring device, a wheel speed sensor 10, a parking brake, etc.

There illustrates a training device 100' which is none other than a first variant of the training device 100 illustrated in the . The drive device 100' comprises a protective casing 101' inside which extends a two-stage reducer 120' similar to the reducer 120, and a radial flux electric motor 110' extending outside the casing 101' and comprising an output shaft 113' connected to the reducer 120' to increase the drive torque delivered by said electric motor 110' to the wheel 10.

The housing 101’ is made in a single part which is fixed to the second end 5b of the axle support 5 via screws 102’ and which delimits an annular space inside which the reducer 120’ extends.

The electric motor 110’ comprises a stator 111’ and a rotor 112’ each having a central axis coincident with the axis X of rotation of the wheel 10. The stator 111’ has the shape of a crown fixedly mounted on an external periphery of the casing 101’, and comprises a pack of sheets 111a’ forming a plurality of teeth which extend radially around the axis X and on which windings 111b’ are wound. The rotor 112’ has the shape of a disk fixedly mounted on the output shaft 113’ of the electric motor 110’. The output shaft 113’ is mounted to be able to rotate about the axis X by means of a bearing 114’ which is received in a bore of the casing 101’. The rotor 112’ extends around the stator 111’ and comprises an annular portion provided internally with a series of magnets 112a’ capable of interacting with the windings 111b’ carried by said stator 111’ to drive the rotor 112’ and therefore the output shaft 113’ in rotation.

The planetary 123.1’ of the first stage of the reducer 120’ is constituted by a free end of the output shaft 113’ of the electric motor 110’, the free end comprising an external periphery provided with teeth distributed angularly in a regular manner around the axis X: the planetary 123.1’ is part of the output shaft 113’, the toothed end of the output shaft 113’ forming an input axis of the reducer 120’.

The outer ring 124’ of the reducer 120’ is constituted by an annular portion of the casing 101’, the annular portion comprising internal teeth meshing with the satellites 121.1’, 121.2’ of each of the stages of the reducer 120’: the outer ring 124’ is part of the casing 101’.

There illustrates a 100'' drive device which is none other than a second variant of the 100 drive device illustrated in . The drive device 100'' comprises a protective casing 101'', of generally tubular shape, inside which extends an electric motor 110'' with radial flux similar to the electric motor 110 and a single-stage reducer 120'' connected to the output shaft 113'' of the electric motor 110'' to increase the drive torque delivered by said electric motor 110'' to the wheel 10.

The housing 101’’ is made in two parts: it comprises a first part 101.1’’ which is fixed to the second end 5b of the axle support 5 via screws 102.1’’ and which delimits with said second end 5b a first annular space inside which the reducer 120’’ extends, and a second part 101.2’’ which is fixed to the first part 101.1’’ via screws 102.2’’ and which delimits with said first part 101.1’’ a second annular space inside which the electric motor 110’’ extends.

The 120’’ reducer is a strain wave reducer. It comprises a 121’’ wave generator mounted to rotate about the X axis, a 122’’ deformable crown mounted on the 121’ wave generator by means of a 123’’ bearing, and an external 124’’ crown with internal teeth meshing with the 122’’ deformable crown.

The wave generator 121’’ comprises an annular element 121a’’ fixedly mounted on one end of the output shaft 113’’ of the electric motor 110’’. The annular element 121a’’ comprises an outer surface of elliptical section whose vertices are in contact with an internal bearing surface of the bearing 123’’.

The deformable crown 122’’ comprises a tubular portion comprising a first end provided with external teeth meshing with the internal teeth of the external crown 124’’, and a second end, opposite the first end, connected by a web to a free end of the first section 6a of the axle 6 by a fixing assembly 127’’: the deformable crown 122’’ is fixed in rotation relative to the wheel 10.

The outer crown 124’’ is formed by the first part 101.1’’ of the casing 101’’ which meshes with the outer teeth of the deformable crown 122’’: the outer crown 124’’ is part of the casing 101’’.

As with the 100 drive device, it should be noted that by combining several functions within the 110’’ electric motor and the 120’’ reducer in a single part, the 100’’ drive device is particularly compact and lightweight.

• sont électriquement alimentés indépendamment des groupes motopropulseurs de l’aéronef 1 ;
• peuvent être ajoutés ou retirés facilement du support d’essieu 5, ce qui simplifie les opérations d’assemblage et de maintenance de l’atterrisseur 2 ;
• permettent à la roue 10 de tourner librement lorsque le moteur électrique 110, 110’, 110’’ n’est pas en fonctionnement, voire en panne ;
• permettent le déplacement au sol de l’aéronef 1 sans utiliser ses groupes motopropulseurs ; et
• permettent de faire tourner la roue 10 avant que l’aéronef 1 touche le sol afin de minimiser l’usure du pneumatique lorsque l’aéronef 1 avance pendant l’atterrissage.

It should be noted that the training devices 100, 100', 100'':

• are electrically powered independently of the aircraft's powertrains 1;
• can be easily added or removed from the axle support 5, which simplifies the assembly and maintenance operations of the lander 2;
• allow the wheel 10 to rotate freely when the electric motor 110, 110', 110'' is not operating or even broken down;
• allow the aircraft 1 to be moved on the ground without using its power units; and
• allow the wheel 10 to be rotated before the aircraft 1 touches the ground in order to minimize tire wear as the aircraft 1 moves forward during landing.

• une roue dentée 201 montée fixe sur une extrémité libre de l’essieu 6 au moyen d’un écrou 202 ;
• un cliquet 203 monté mobile en rotation autour d’un axe X’ parallèle à l’axe X de rotation de l’essieu 6 entre une position d’arrêt en rotation dans laquelle une extrémité du cliquet 203 est logée entre deux dents de la roue dentée 201 ( ) et une position de libre rotation dans laquelle l’extrémité du cliquet 203 est éloignée de la roue dentée 201 ;
• un ressort de torsion 204 rappelant le cliquet dans la position dégagée ; et
• un actionneur 205 mécanique ou électrique agencé pour amener le cliquet 203 de la position dégagée vers la position engagée à l’encontre du ressort de torsion 204.

With reference to FIGS. 5A and 5B, the landing gear 2 may optionally be equipped with a parking brake for immobilizing the wheel 10 in rotation about its axis X, and therefore immobilizing the aircraft 1 on the ground. The parking brake comprises, for example, a rotation-stopping device 200 comprising:

• a toothed wheel 201 fixedly mounted on a free end of the axle 6 by means of a nut 202;
• a ratchet 203 mounted to rotate about an axis X' parallel to the axis X of rotation of the axle 6 between a rotation stop position in which one end of the ratchet 203 is housed between two teeth of the toothed wheel 201 ( ) and a free rotation position in which the end of the pawl 203 is moved away from the toothed wheel 201;
• a torsion spring 204 biasing the pawl into the released position; and
• a mechanical or electrical actuator 205 arranged to bring the pawl 203 from the disengaged position to the engaged position against the torsion spring 204.

It is understood that in the stopped position, the axle 6 and therefore the wheel 10 are blocked in rotation, and that in the free rotation position, said axle 6 and said wheel 10 are free to rotate around the axis X.

The toothed wheel here bears against an inner ring of the second bearing 7.2, and is housed with the pawl 203 in a bore made in the first end 5a of the axle support 5 in order to limit the aerodynamic impact of the landing gear 2.

It will be noted that the rotation stop device 200 is simple to add and remove from the drive device 100, 100’, 100’’.

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.

The wheel 10 may have a structure different from that described. The rim of the wheel may for example be formed of two half-rims, be made in a single piece, made in a foundry or by additive manufacturing…

Although the 110, 110’, 110’’ engine is electric here, it can be of another type (hydraulic, pneumatic, thermal, etc.).

Although here the 110, 110’, 110’’ electric motor is radial flux, it can also be axial flux.

Although here the rotor 112 of the electric motor 110 extends inside the stator 111, the rotor 112 can, conversely, extend around the stator 111, 111'.

Although here the stator 111’ of the electric motor 110’ extends inside the rotor 112’, the stator 111’ can, conversely, extend around the rotor 112’.

The 110, 110’, 110’’ electric motor can be of the “pancake” type, that is to say wide and flat and presenting rapid acceleration and deceleration using a high number of pole pairs.

The 110, 110’, 110’’ electric motor and the 120, 120’, 120’’ reducer can be replaced by a geared motor.

The magnets 112a, 112a’ may be carried by the stator 111, 111’ instead of the rotor 112, 112’.

The 120, 120’, 120’’ reducer is optional.

Although the planetary 123.1 of the reducer 120 is here part of the output shaft 113 of the electric motor 110, it could be made in two separate parts connected together by an interface making it easier to disassemble and maintain the electric motor 110.

Although the 120, 120’ planetary reducer is here two-stage, it can comprise a single stage or a number of stages greater than two.

Although the 120’’ strain wave reducer is single-stage here, it can include a plurality of stages.

The reducer 120, 120’, 120’’ may be of other types than those described. For example, it may be a cycloidal reducer, a stepped planetary reducer, etc.

The number of satellites can be more or less than four.

The invention can be used on any type of vehicle, air, land or amphibious, or any mobile industrial or transport equipment requiring braking.

Claims (10)

Running gear for a vehicle (1) comprising an axle support (5) in which an axle (6) is mounted so as to be rotatable, the axle comprising a first end on which a wheel (10) is fixedly mounted, and a second end, opposite the first end, connected to a drive device (100, 100', 100'') arranged to drive the axle in rotation. Running gear according to claim 1, wherein the wheel (10) and the drive device (100, 100', 100'') extend axially on either side of the axle support (5). Running gear according to any one of the preceding claims, wherein the drive device (100, 100', 100") comprises an electric motor (110, 110', 110"). Running gear according to claim 3, in which the electric motor (110, 110’, 110’’) is radial flux. Running gear according to any one of the preceding claims, in which the drive device (100, 100', 100") comprises a reducer (120, 120', 120"), an output shaft of which is rotationally connected to the second end of the axle (6). Running gear according to claim 5, in which the reducer (120, 120') is a planetary reducer. Running gear according to claim 5, in which the reducer (120’’) is a strain wave reducer. Running gear according to any one of claims 5 to 7, in which the reducer (120, 120') is a multi-stage reducer. Aircraft landing gear (2) comprising one end comprising a running gear according to any one of the preceding claims. Aircraft (1) comprising at least one landing gear (2) according to claim 9.