Landing gear system for aircraft and associated aircraft

Abstract

A landing gear system (5) for an aircraft (1), the landing gear system comprising a front landing gear (2) and at least one rear landing gear, the rear landing gear being of the bogie beam type and comprising at least two wheels, the landing gear system furthermore being equipped with a hybrid braking system comprising at least one friction brake and at least one auxiliary brake providing energy dissipation by means other than friction, at least one of the wheels of the rear landing gear being equipped solely with one or more auxiliary brakes and at least one of the wheels of the rear landing gear being equipped solely with one or more friction brakes, all the wheels of the rear landing gear being equipped with at least one auxiliary brake or with a friction brake. An aircraft equipped with such a landing gear system.

Description

[0001] LANDING GEAR SYSTEM FOR AIRCRAFT AND ASSOCIATED AIRCRAFT

[0002] The present invention relates to a landing gear system for an aircraft.

[0003] The present invention also relates to an aircraft equipped with such a landing gear system.

[0004] BACKGROUND OF THE INVENTION

[0005] In the field of aviation, it is well known to equip aircraft wheels with a friction brake intended to selectively slow down and stop said aircraft when they are moving on the ground or during landing phases. Friction brakes, although effective, require the replacement of wear elements on a regular basis. In addition, the friction of these wear elements, during braking, generates particularly polluting dust particles.

[0006] 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 to both new aircraft types and those currently in operation, requiring the implementation of technological solutions 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.

[0007] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. All stakeholders 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.

[0008] 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.

[0009] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to ensure propulsion, and, as an essential complement to technological progress, aeronautical biofuels.

[0010] SUBJECT OF THE INVENTION

[0011] The aim of the invention is to propose a landing gear system and an aircraft making it possible to at least partially overcome the aforementioned drawbacks.

[0012] SUMMARY OF THE INVENTION

[0013] For this purpose, according to the invention, a landing gear system for an aircraft is provided, the landing gear system comprising a front landing gear and at least one rear landing gear, the rear landing gear having a bogie balance beam and comprising at least two wheels, the landing gear system being further equipped with a hybrid braking system comprising at least one friction brake and at least one auxiliary brake ensuring energy dissipation by means other than friction, at least one of the wheels of the rear landing gear being equipped only with one or more auxiliary brakes and at least one of the wheels of the rear landing gear being equipped only with one or more friction brakes, all the wheels of the rear landing gear being equipped with at least one auxiliary brake or a friction brake.

[0014] This means that the landing gear of the aircraft is equipped not only with at least one friction brake but also with at least one auxiliary brake ensuring energy dissipation other than by friction.

[0015] Thanks to this hybrid braking system, it is possible to use at least one friction brake less, particularly during ground movement or landing phases.

[0016] This limits pollution of the ambient air by particles released during friction between the wear elements of the friction brake(s).

[0017] This also helps to limit an increase in temperature in the friction brake(s), which tends to accelerate their aging.

[0018] In the invention, all the rear landing gears have at least one wheel equipped with only one friction brake or only several friction brakes (i.e. have at least one wheel without an auxiliary brake).

[0019] For the present application, "landing gear system" means the entire system deployed to enable an aircraft to land and then taxi on the ground.

[0020] Landing gear refers to each unit of the landing gear system connected to the aircraft by a landing leg. A landing gear system thus comprises several landing gears. Note that a landing gear can itself carry one or more wheels.

[0021] For the purposes of this application, the terms "front" and "rear" shall be understood to refer to the longitudinal axis passing through the aircraft, the front of the aircraft being its nose and the rear of the aircraft being its tail.

[0022] For the purposes of this application, the terms "right" and "left" shall be understood to refer to the longitudinal axis passing through the aircraft when viewing the aircraft from the rear of the aircraft when it is on the ground, from its tail towards its nose, with right and left designating the two sides of the aircraft respectively.

[0023] Preferably, the rear landing gear is a first landing gear, the landing gear system comprising a second rear landing gear, the second rear landing gear being a bogie balancer and comprising at least two wheels, at least one of the wheels of the second landing gear being equipped only with one or more friction brakes.

[0024] Preferably, the number of wheels equipped with friction brakes of the entire rear landing gear of the aircraft is equal to or greater than the number of wheels equipped with auxiliary brakes of the entire rear landing gear of the aircraft.

[0025] Optionally, the rear landing gear is a first landing gear, the landing gear system comprising a second rear landing gear, the second rear landing gear being a bogie balancer and comprising at least two wheels, at least one of the wheels of the second landing gear being equipped only with one or more friction brakes.

[0026] Optionally, the number of wheels equipped with friction brakes on all the rear landing gear of the aircraft is equal to or greater than the number of wheels equipped with auxiliary brakes on all the rear landing gear of the aircraft.

[0027] Optionally at least one of the auxiliary brakes is a magnetic brake.

[0028] Optionally, the magnetic brake is an eddy current brake.

[0029] Optionally, the landing gear system comprises at least three rear landing gears all with bogie balancer, namely a center landing gear, a right landing gear and a left landing gear, in which the wheels of the right and left landing gears are equipped with friction brakes only and the wheels of the center landing gear are equipped with auxiliary brakes only.

[0030] Optionally at least one of the rear landing gears comprises at least one bogie balancer and at least one first axle extending transversely to the bogie balancer and at least one second axle extending transversely to the bogie balancer, each axle being associated with at least one right wheel and at least one left wheel.

[0031] Optionally, the wheels associated with the first axle are only equipped with auxiliary brakes and the wheels associated with the second axle are only equipped with friction brakes or vice versa.

[0032] Optionally, the first axle with wheels equipped only with auxiliary brakes is arranged in front of the second axle with wheels equipped only with friction brakes or in which the first axle with wheels equipped only with auxiliary brakes is arranged in the rear of the second axle with wheels equipped only with friction brakes.

[0033] Optionally, the wheels on one side of the landing gear are equipped with auxiliary brakes only and the wheels on the other side of the landing gear are equipped with friction brakes only.

[0034] Optionally, the wheels equipped with auxiliary brakes are the right wheels or the left wheels. Optionally, the wheels equipped with friction brakes are the wheels furthest from a longitudinal axis (X) of the aircraft or are the wheels closest to said axis.

[0035] The invention also relates to an aircraft comprising a landing gear system as mentioned above.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The invention will be better understood in light of the following description, which is purely illustrative and non-limiting, and must be read in conjunction with the appended drawings, among which: [Fig.l] Figure 1 is a simplified top view of an aircraft comprising a landing gear system according to a first embodiment of the invention, the landing gear system being shown in dotted lines so that it can be seen in Figure 1; [Fig.2] Figure 2 is an enlarged top view of one of the landing gears of the aircraft illustrated in Figure 1;

[0038] [Fig.3] Figure 3 is a simplified top view of an aircraft comprising a landing gear system according to a second embodiment of the invention, the landing gear system being shown in dotted lines so that it can be seen in Figure 3.

[0039] DETAILED DESCRIPTION OF THE INVENTION

[0040] With reference to Figures 1 and 2, an aircraft 1 according to a first embodiment will now be described. The aircraft 1 comprises an aircraft landing gear system 5 which here comprises a front landing gear 2 and two main landing gears, namely a left rear landing gear 3a and a right rear landing gear 3b. The front landing gear 2 is arranged under the fuselage 6 in front of the left rear landing gear 3a and in front of the right rear landing gear 3b which are arranged under the left wing 7a and the right wing 7b of the aircraft 1 respectively.

[0041] The front landing gear 2 has a single axle 8 supporting two wheels 9. The front landing gear 2 is therefore not a bogie landing gear.

[0042] On the other hand, the left rear landing gear 3a and the right rear landing gear 3b are both bogie balancers.

[0043] Therefore, each of these landing gears 3a, 3b comprises a leg carrying a shock absorber assembly which is coupled to a bogie balancer, the bogie balancer thus extending the leg.

[0044] Each bogie balancer comprises a main body 10 elongated along an axis A which here extends parallel to the longitudinal axis X of the aircraft 1 (axis going from the tail to the nose of the aircraft 1) when the landing gear is deployed. The main body 10 is provided at a first end with a first sleeve 11 and at a second end with a second sleeve 12 extending parallel to the first sleeve 11. The two sleeves 11, 12 also extend orthogonally to the main body 10. A first axle 13 extends through the first sleeve 11 coaxially thereto and a second axle 14 extends through the second sleeve 12 coaxially thereto. Each axle 13, 14 here carries at each of its ends at least one wheel.

[0045] In the present case, the left rear landing gear 3a and the right rear landing gear 3b are both four-wheel bogie balancers so that each axle 13, 14 carries a single wheel at each of its ends.

[0046] The left rear landing gear 3a thus comprises a front axle 13 (the first axle) carrying a left wheel 15a and a right wheel 15b as well as a rear axle 14 (the second axle) carrying a left wheel 16a and a right wheel 16b.

[0047] In the same way, the right rear landing gear 3b thus comprises a front axle 17 (the first axle) carrying a left wheel 18a and a right wheel 18b as well as a rear axle 19 (the second axle) carrying a left wheel 20a and a right wheel 20b.

[0048] The landing gear system 5 is also equipped with a hybrid braking system comprising friction brakes and auxiliary brakes ensuring energy dissipation by means other than friction. The friction brakes comprise, in a manner known per se, both rotor discs linked to the wheel in question and stator discs linked to the axle or to another part of the associated landing gear: when it is desired to exert a braking force, at least one actuator (hydraulic and / or electric) presses against a pressure distribution plate which in turn presses the various discs against each other in the direction of an end plate. The friction between the rotor discs and the stator discs thus causes the rotor discs to stop.

[0049] At least one of the friction discs comprises a main body on which at least one friction pad is attached and / or comprises a main body directly forming a friction pad.

[0050] At least one of the discs can thus be carbon-based and / or metal-based (steel for example).

[0051] For example, at least one of the discs is metal-based and is equipped with at least one friction pad at at least one of its ends and / or at least one of the discs is carbon-based and therefore directly forms a friction disc (which is therefore devoid of a friction pad).

[0052] The auxiliary brakes are preferably magnetic brakes.

[0053] The auxiliary brakes are preferably eddy current brakes.

[0054] Each auxiliary brake thus comprises a stator linked to the axle or to another part of the landing gear considered and a rotor linked to the associated wheel, one carrying magnetic elements (permanent magnets and / or electromagnets and / or a combination of the two) and the other at least one electrically conductive surface. The rotary movement between the stator and the rotor causes a rotary movement of said surface in the magnetic field generated by the magnetic elements: this causes the generation of eddy currents inside said surface which in turn cause a transformation of the kinetic energy between the stator and the rotor into heat dissipation, thus braking the rotor with respect to the stator.

[0055] The front landing gear 2 is preferably without brakes.

[0056] Different configurations are possible for the left 3a and right 3b rear landing gears. In all cases, at least one of the rear landing gears 3a, 3b is equipped with at least one auxiliary brake and at least one of the rear landing gears 3a, 3b is equipped with at least one friction brake. Preferably, the number of wheels equipped with friction brakes of the rear landing gears 3a, 3b is equal to or greater than the number of wheels equipped with auxiliary brakes of the rear landing gears 3a, 3b. According to a first configuration, the two wheels 15a, 15b of the front axle 13 of the left rear landing gear 3a and the two wheels 18a, 18b of the front axle 17 of the right rear landing gear 3b are only equipped with auxiliary brakes (i.e. they are not equipped with friction brakes).Furthermore, the two wheels 16a, 16b of the rear axle 14 of the left rear landing gear 3a and the two wheels 20a, 20b of the rear axle 19 of the right rear landing gear 3b are only equipped with friction brakes (i.e. they are not equipped with auxiliary brakes).

[0057] According to a second configuration, the two wheels 16a, 16b of the rear axle 14 of the left rear landing gear 3a and the two wheels 20a, 20b of the rear axle 19 of the right rear landing gear 3b are only equipped with auxiliary brakes (i.e. they are not equipped with friction brakes). Furthermore, the two wheels 15a, 15b of the front axle 13 of the left rear landing gear 3a and the two wheels 18a, 18b of the front axle 17 of the right rear landing gear 3b are only equipped with friction brakes (i.e. they are not equipped with auxiliary brakes).

[0058] According to a third configuration, the two left wheels 15a, 16a of the left rear landing gear 3a and the two left wheels 18a, 20a of the right rear landing gear 3b are only equipped with auxiliary brakes (i.e., they are not equipped with friction brakes). Furthermore, the two right wheels 15b, 16b of the left rear landing gear 3a and the two right wheels 18b, 20b of the right rear landing gear 3b are only equipped with friction brakes (i.e., they are not equipped with auxiliary brakes). According to a fourth configuration, the two right wheels 15b, 16b of the left rear landing gear 3a and the two right wheels 18b, 20b of the right rear landing gear 3b are only equipped with auxiliary brakes (i.e. they are not equipped with friction brakes).Furthermore, the two left wheels 15a, 16a of the left rear landing gear 3a and the two left wheels 18a, 20a of the right rear landing gear 3b are only equipped with friction brakes (i.e., they are not equipped with auxiliary brakes). According to a fifth configuration, the two right wheels 15b, 16b of the left rear landing gear 3a and the two left wheels 18a, 20a of the right rear landing gear 3b are only equipped with auxiliary brakes (i.e., they are not equipped with friction brakes). Furthermore, the two left wheels 15a, 16a of the left rear landing gear 3a and the two right wheels 18b, 20b of the right rear landing gear 3b are only equipped with friction brakes (i.e. they are not equipped with auxiliary brakes). It is therefore the innermost wheels with respect to the X axis of the aircraft 1 which are equipped with auxiliary brakes.

[0059] According to a sixth configuration, the two left wheels 15a, 16a of the left rear landing gear 3a and the two right wheels 18b, 20b of the right rear landing gear 3b are equipped only with auxiliary brakes (i.e. they are not equipped with friction brakes). Furthermore, the two right wheels 15b, 16b of the left rear landing gear 3a and the two left wheels 18a, 20a of the right rear landing gear 3b are equipped only with friction brakes (i.e. they are not equipped with auxiliary brakes). It is therefore the outermost wheels with respect to the X axis of the aircraft 1 which are therefore equipped with auxiliary brakes. In all these configurations, each rear landing gear 3a, 3b has at least one wheel equipped only with a friction brake.

[0060] In all configurations herein, the number of wheels of the rear landing gears 3a, 3b equipped with auxiliary brakes is equal to the number of wheels of the rear landing gears 3a, 3b equipped with friction brakes. The braking system is preferably configured so that the first group formed by the friction brakes and the second group formed by the auxiliary brakes can be controlled independently of one another. In this way, it is thus possible to control all the friction brakes together or all the auxiliary brakes together or, if desired, all the brakes together. This makes it possible to better control the braking and in particular to be able to activate only the auxiliary brakes if the braking force developed by them is sufficient in the phase concerned.

[0061] Thus, during taxiing maneuvers where the speed of aircraft 1 is relatively low and where the traffic on the runway may require the activation and deactivation of the brakes while aircraft 1 is positioned for takeoff, the auxiliary brakes can be used independently of the friction brakes (to avoid the application of the friction brakes). This can have a significant impact on extending the life of the friction brake components.

[0062] Furthermore, during landing maneuvers where the speed of the aircraft 1 is relatively high, the auxiliary brakes can be used in addition to the friction brakes and other resistive forces (drag, reverse thrust, etc.) to absorb energy and reduce the force required by the other braking systems, and / or allow shorter landing distances. With reference to Figure 3, an aircraft according to a second embodiment will be described.

[0063] The aircraft 1 comprises an aircraft landing gear system 5 which here comprises a front landing gear 2 and three rear landing gears:

[0064] - a central rear landing gear 4, and

[0065] - two rear main landing gears, namely a left rear landing gear 3a and a right rear landing gear 3b.

[0066] The rear center landing gear 4 is arranged under the fuselage 6 of the aircraft 1 behind the front landing gear 2 and in front of the left rear landing gear 3a and the right rear landing gear 3b. The front landing gear 2 is arranged under the fuselage 6 in front of the left rear landing gear 3a and the right rear landing gear 3b which are both arranged under the left wing 7a and the right wing 7b of the aircraft 1 respectively.

[0067] The front landing gear 2 comprises a single axle 8 here supporting two wheels 9. The front landing gear 2 is therefore not a bogie landing gear.

[0068] On the other hand, the rear center landing gear 4, the left rear landing gear 3a and the right rear landing gear 3b are all three with bogie balancer.

[0069] Therefore, each of these landing gears 4, 3a, 3b comprises a leg carrying a shock absorber assembly which is coupled to a bogie balancer, the bogie balancer thus extending the leg.

[0070] Each bogie balancer comprises a main body 10 elongated along an axis A which here extends parallel to the longitudinal axis X of the aircraft 1 (axis going from the tail to the nose of the aircraft 1) when the landing gear is deployed. The main body 10 is provided at a first end with a first sleeve and at a second end with a second sleeve extending parallel to the first sleeve. The two sleeves also extend orthogonally to the main body 10. A first axle 13 extends through the first sleeve coaxially thereto and a second axle 14 extends through the second sleeve coaxially thereto. Each axle 13, 14 here carries at each of its ends at least one wheel.

[0071] In the present case, the rear central landing gear 4, the left rear landing gear 3a and the right rear landing gear 3b are all three with four-wheel bogie balancer so that each axle carries a single wheel at each of its ends. The left rear landing gear 3a thus comprises a front axle 13 (the first axle) carrying a right wheel and a left wheel as well as a rear axle 14 (the second axle) carrying a right wheel and a left wheel.

[0072] Similarly, the right rear landing gear 3b thus comprises a front axle 30 (the first axle) carrying a right wheel and a left wheel as well as a rear axle 31 (the second axle) carrying a right wheel and a left wheel.

[0073] Similarly, the rear central landing gear 4 thus comprises a front axle 32 (the first axle) carrying a right wheel and a left wheel as well as a rear axle 33 (the second axle) carrying a right wheel and a left wheel.

[0074] The landing gear system 5 is also equipped with a hybrid braking system comprising friction brakes and auxiliary brakes ensuring energy dissipation by means other than friction. The friction brakes comprise, in a manner known per se, both rotor discs linked to the wheel in question and stator discs linked to the axle or to another part of the associated landing gear: when it is desired to exert a braking force, at least one actuator (hydraulic and / or electric) presses against a pressure distribution plate which in turn presses the various discs against each other in the direction of an end plate. The friction between the rotor discs and the stator discs thus causes the rotor discs to stop.

[0075] At least one of the discs comprises a main body on which at least one friction pad is attached and / or comprises a main body directly forming a friction pad.

[0076] At least one of the discs can thus be carbon-based and / or metal-based (steel for example).

[0077] For example, at least one of the discs is metal-based and is equipped with at least one friction pad at at least one of its ends and / or at least one of the discs is carbon-based and therefore directly forms a friction disc (which is therefore devoid of a friction pad).

[0078] The auxiliary brakes are preferably magnetic brakes.

[0079] The auxiliary brakes are preferably eddy current brakes.

[0080] Each auxiliary brake thus comprises a stator linked to the axle or to another part of the landing gear considered and a rotor linked to the associated wheel, one carrying magnetic elements (permanent magnets and / or electromagnets and / or a combination of the two) and the other at least one electrically conductive surface. The rotary movement between the stator and the rotor causes a rotary movement of said surface in the magnetic field generated by the magnetic elements: this causes the generation of eddy currents inside said surface which in turn cause a transformation of the kinetic energy between the stator and the rotor into heat dissipation, thus braking the rotor with respect to the stator.

[0081] The front landing gear 2 is preferably without brakes.

[0082] Different configurations are possible for the right rear landing gear 3b and left rear landing gear 3a and central rear landing gear 4. In all cases, at least one of the rear landing gears 3a, 3b, 4 is equipped with at least one auxiliary brake and at least one of the rear landing gears 3a, 3b, 4 is equipped with at least one friction brake.

[0083] Preferably, the number of wheels equipped with friction brakes of the rear landing gears 3a, 3b, 4 is equal to or greater than the number of wheels equipped with auxiliary brakes equipping the rear landing gears 3a, 3b, 4.

[0084] For example, all wheels of the rear center landing gear 4 are equipped with only auxiliary brakes (i.e., they are not equipped with friction brakes). Furthermore, all wheels of the right rear landing gear 3b and all wheels of the left rear landing gear 3a are equipped with only friction brakes (i.e., they are not equipped with auxiliary brakes).

[0085] The number of wheels of the rear landing gears 3a, 3b, 4 equipped with auxiliary brakes is then less than the number of wheels of the rear landing gears 3a, 3b, 4 equipped with friction brakes.

[0086] The braking system is preferably configured so that the first group formed by the friction brakes and the second group formed by the auxiliary brakes can be controlled independently of each other. In this way, it is possible to control all the friction brakes together or all the auxiliary brakes together or, if desired, all the brakes together.

[0087] This allows for better braking control and in particular to only activate the auxiliary brakes if the braking force developed by them is sufficient in the phase concerned.

[0088] Thus, during taxiing maneuvers where the speed of aircraft 1 is relatively low and where the traffic on the runway may require the activation and deactivation of the brakes while aircraft 1 is positioned for takeoff, the auxiliary brakes can be used independently of the friction brakes (to avoid the application of the friction brakes). This can have a significant impact on extending the life of the friction brake components.

[0089] Additionally, during landing maneuvers where the speed of the aircraft 1 is relatively high, the auxiliary brakes may be used in addition to the friction brakes and other resistive forces (drag, reverse thrust, etc.) to absorb energy and reduce the force required by the other braking systems, and / or allow shorter landing distances.

[0090] 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.

[0091] In particular, the number of landing gears included in the landing gear system may differ from what has been indicated. The landing gears may be arranged differently from what has been indicated.

[0092] The nose landing gear may be equipped with at least one brake. For example, one or more wheels of the nose landing gear may be equipped with a friction brake and / or an auxiliary brake.

[0093] The landing gear system may only include bogie balancer landing gear.

[0094] For a bogie-balanced landing gear, it may include more axles than two and / or include more wheels (than two) carried by at least one of the axles. For example, at least one of the axles may carry four wheels or six wheels. Other configurations than those described are of course possible.

[0095] For example in the case of two rear landing gears where each landing gear has four wheels, as in the first embodiment:

[0096] - the number of rear landing gear wheels fitted with auxiliary brakes may be less than the number of rear landing gear wheels fitted with friction brakes. For example, only one wheel per rear landing gear may be fitted with an auxiliary brake, the others being fitted with a friction brake;

[0097] - the number of rear landing gear wheels fitted with auxiliary brakes may be greater than the number of rear landing gear wheels fitted with friction brakes. For example, only one wheel per rear landing gear may be fitted with a friction brake, the others being fitted with an auxiliary brake - etc.

[0098] For example in the case of three rear landing gears, as in the second embodiment:

[0099] - all front wheels of all rear landing gears may be equipped with one or more auxiliary brakes and all rear wheels of all rear landing gears may be equipped with one or more friction brakes; - all front wheels of all rear landing gears may be equipped with one or more friction brakes and all rear wheels of all rear landing gears may be equipped with one or more auxiliary brakes;

[0100] - all right wheels of all rear landing gear may be equipped with one or more friction brakes and all left wheels of all rear landing gear may be equipped with one or more auxiliary brakes;

[0101] - all right wheels of all rear landing gear may be equipped with one or more auxiliary brakes and all left wheels of all rear landing gear may be equipped with one or more friction brakes;

[0102] - the number of rear landing gear wheels fitted with auxiliary brakes may be less than the number of rear landing gear wheels fitted with friction brakes. For example, only one wheel per rear landing gear may be fitted with an auxiliary brake, the others being fitted with a friction brake;

[0103] - the number of rear landing gear wheels fitted with auxiliary brakes may be greater than the number of rear landing gear wheels fitted with friction brakes. For example, only one wheel per rear landing gear may be fitted with a friction brake, the others being fitted with an auxiliary brake;

[0104] - at least one of the right or left landing gears may be equipped with friction brakes only,

[0105] - etc .

[0106] In all configurations, each rear landing gear will be provided with at least one wheel equipped with one or more friction brakes and preferably will be provided with at least one wheel equipped solely with one or more friction brakes. Preferably, in all configurations, all wheels of all rear landing gears will be provided with at least one brake.

[0107] Preferably, the braking system will be configured so that the distribution of the brakes in the rear landing gears is symmetrical along at least one axis (for example the longitudinal axis X of the aircraft corresponding to the roll axis or the pitch axis of the aircraft or the yaw axis of the aircraft). For example, it will be possible to have a distribution of the left wheels of the rear landing gears with a first type of brakes and the right wheels of the rear landing gears with a second type of brakes or a distribution of the front wheels of the rear landing gears with a first type of brakes and the rear wheels of the rear landing gears with a second type of brakes.

[0108] Of course, in all configurations, the braking system must ensure sufficient braking in all phases considered, particularly that of landing.

[0109] At least one of the auxiliary brakes may be of a type other than magnetic and, for example, may be hydraulic (such as a "retarder" brake) or compressed air (such as a "turbobrake"). The hybrid braking system may include several types of auxiliary brakes within the same aircraft.

[0110] The auxiliary brakes will preferably be contactless. The auxiliary brakes will in any case not be friction brakes.

Claims

CLAIMS 1. Landing gear system (5) for an aircraft (1), the landing gear system comprising a front landing gear (2) and at least one rear landing gear, the rear landing gear being a bogie balancer and comprising at least two wheels, the landing gear system being further equipped with a hybrid braking system comprising at least one friction brake and at least one auxiliary brake providing energy dissipation by means other than friction, at least one of the wheels of the rear landing gear being equipped only with one or more auxiliary brakes and at least one of the wheels of the rear landing gear being equipped only with one or more friction brakes, all the wheels of the rear landing gear being equipped with at least one auxiliary brake or a friction brake.

2. Landing gear system (5) according to claim 1, wherein the rear landing gear is a first landing gear, the landing gear system comprising a second rear landing gear, the second rear landing gear being a bogie balancer and comprising at least two wheels, at least one of the wheels of the second landing gear being equipped only with one or more friction brakes.

3. Landing gear system (5) according to one of claims 1 or 2, in which the number of wheels equipped with friction brakes of the set of rear landing gears of the aircraft (1) is equal to or greater than the number of wheels equipped with auxiliary brakes of the set of rear landing gears of the aircraft.

4. Landing gear system (5) according to one of the preceding claims, wherein at least one of the auxiliary brakes is a magnetic brake.

5. Landing gear system (5) according to the preceding claim, wherein the magnetic brake is an eddy current brake.

6. Landing gear system (5) according to one of the preceding claims, comprising at least three rear landing gears all with bogie balancer, namely a central landing gear (4), a right landing gear (3b) and a left landing gear (3a), in which the wheels of the right and left landing gears are only equipped with friction brakes and the wheels of the central landing gear are only equipped with auxiliary brakes.

7. Landing gear system (5) according to one of claims 1 to 6, wherein at least one of the rear landing gears (3a, 3b, 4) comprises at least one bogie balancer and at least one first axle extending transversely to the bogie balancer and at least one second axle extending transversely to the bogie balancer, each axle being associated with at least one right wheel and at least one left wheel.

8. Landing gear system (5) according to claim 7, wherein the wheels associated with the first axle are only equipped with auxiliary brakes and the wheels associated with the second axle are only equipped with friction brakes or vice versa.

9. Landing gear system (5) according to claim 8, wherein the first axle with wheels equipped only with auxiliary brakes is arranged in front of the second axle with wheels equipped only with friction brakes or wherein the first axle with wheels equipped only with auxiliary brakes is arranged in the rear of the second axle with wheels equipped only with friction brakes.

10. Landing gear system (5) according to the Claim 7, wherein the wheels on one side of the landing gear are equipped with only auxiliary brakes and the wheels on the other side of the landing gear are equipped with only friction brakes.

11. Aircraft (1) comprising a landing gear system (5) according to one of the preceding claims.

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