Method for limiting the wear of brake discs fitted to aircraft landing gear wheels.

Abstract

A method for limiting wear on brake discs (2a, 2b) (1) of two braked wheels (R1.1, R1.2, R2.1, R2.2; R1.1', … R1.4', R2.1', … R2.4'; R1.1'', … R1.6'', R2.1'', … R2.6'') mounted for rotation on an axle of a landing gear (L1, L2; L1', L2'; L1'', L2'') of an aircraft (A; A'; A''), the method comprising, when the aircraft is traveling at a speed (V; V'; V'') lower than a predetermined speed and a pilot of said aircraft applies the brakes to the landing gear wheels, the following steps: acquisition of a temperature (T1.1, T1.2, T2.1, T2.2 ; T1.1', … T1.4', T2.1', … T2.4' ; T1.1'', … T1.6'', T2.1'', … T2.6'') of the brake discs of each of the two wheels; determination of the wheel whose brake has the lowest or highest temperature; activation of the brake with the lowest or highest temperature depending on the material from which the brake discs are made. FIGURE FROM THE ABRIDGED: Fig.5

Description

Title of the invention: Method for limiting the wear of brake discs fitted to aircraft landing gear wheels.

[0001] The present invention relates to the field of aeronautics and more particularly to the wear of brakes fitted to aircraft wheels.

[0002] BACKGROUND OF THE INVENTION

[0003] An aircraft landing gear generally comprises a leg having a first end connected to a structure of the aircraft and a second end provided with a shaft or axle on which a wheel is mounted to pivot. The wheel comprises a rim connected by a web to a hub which receives the shaft of the leg and defines with the rim a space in which is arranged a stack of discs comprising alternating stator discs fixed relative to the shaft and rotor discs fixed relative to the rim. The discs are generally made of carbon-carbon material. An actuator, for example a hydraulic cylinder, is arranged to exert a pressing force on the stack of discs via a hydraulic crown. The rim comprises two annular edges or beads between which a tire is mounted.

[0004] Each braking action carried out by the pilot of an aircraft causes friction of the discs, resulting in an instantaneous increase in the temperature of said discs but also wear of their contact faces.

[0005] For certain carbon-carbon materials, the wear of the discs is all the more significant when their temperature is low. Braking carried out when the discs are "cold" can thus, even at low speed, significantly wear said discs.

[0006] For other carbon-carbon materials, the wear of the discs is all the more significant as their temperature is high. Braking carried out when the discs are "hot" can thus, even at low speed, significantly wear said discs.

[0007] 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 and 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.

[0008] 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. 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.

[0009] 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.

[0010] This sustained research and development work covers new generations of aircraft engines, the lightening 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 essential complements to technological progress, aeronautical biofuels.

[0011] SUBJECT OF THE INVENTION

[0012] The invention results from this work and aims to propose a method for limiting the wear of brake discs fitted to aircraft landing gear wheels. Summary of the invention

[0013] To this end, a method is provided for limiting the wear of brake discs of two braked wheels mounted for rotation on an axle of an aircraft landing gear. According to the invention, the method comprises, when the aircraft is traveling at a speed lower than a predetermined speed and a pilot of said aircraft actuates the brake of the landing gear wheels, the following steps: • acquisition of a temperature of the brake discs of each of the two wheels; • determination of the wheel whose brake has the lowest or highest temperature; and • activation of the brake with the lowest or highest temperature depending on the material from which the brake discs are made.

[0014] Such a method makes it possible, in particular during taxiing phases which do not require the use of the brakes on both wheels, to brake only one of the two wheels and to use the brake least subject to wear so as to significantly improve the longevity of the brake discs. On the other hand, when the speed is equal to or greater than the predetermined speed, the brakes on all wheels are activated.

[0015] According to a particular characteristic, the predetermined speed is between 15 knots and 25 knots.

[0016] In particular, the predetermined speed is equal to 20 knots.

[0017] The invention also relates to an aircraft comprising: • a first main landing gear and a second main landing gear each comprising at least one axle provided with two wheels, each of the wheels being equipped with a brake comprising brake discs, • an electronic brake control unit connected to wheel brake temperature sensors, and receiving a signal representative of the aircraft's forward speed,

[0018] the electronic control unit being arranged to implement such a method. Brief description of the drawings

[0019] 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:

[0020] [Fig-1] [Fig.l] is a front view of an aircraft including landing gears main ones each equipped with two braked wheels;

[0021] [Fig.2] [Fig.2] is a bottom view of the aircraft illustrated in [Fig.l];

[0022] [Fig.3A] [Fig.3A] is an axial sectional view of one of the braked wheels of the aircraft illustrated in [Fig.l];

[0023] [Fig.3B] [Fig.3B] is a rear view of the wheel brake illustrated in [Fig.3A];

[0024] [Fig.4] [Fig.4] represents the braked wheels of the aircraft illustrated in [Fig.l];

[0025] [Fig.5] [Fig.5] is a flowchart illustrating a method for limiting wear of brakes of the braked wheels of the aircraft illustrated in [Fig.l], according to a particular embodiment of the invention;

[0026] [Fig.6A] [Fig.6A] is a view similar to [Fig.2], illustrating a first variant of the main landing gear of the aircraft illustrated in [Fig.2];

[0027] [Fig.6B] [Fig.6B] is analogous to [Fig.4], illustrating the braked wheels of the aircraft illustrated in [Fig.6A];

[0028] [Fig.6C] [Fig.6C] is a flowchart illustrating a method for limiting the wear of the brakes of the braked wheels of the aircraft illustrated in [Fig.6B], according to a particular embodiment of the invention;

[0029] [Fig.7A] [Fig.7A] is a view similar to [Fig.6A], illustrating a second variant of the main landing gear of the aircraft illustrated in [Fig.2];

[0030] [Fig.7B] [Fig.7B] is analogous to [Fig.6B], illustrating the braked wheels of the aircraft illustrated in [Fig.7A];

[0031] [Fig.7C] [Fig.7C] is a flowchart illustrating a method for limiting wear of brakes of the braked wheels of the aircraft illustrated in [Fig.7B], according to a particular embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] With reference to Figures 1 and 2, the invention is described in application to an aircraft A comprising a first main landing gear Li and a second main landing gear L2. The first landing gear Li and the second landing gear L2 are arranged respectively to the right and to the left of a median longitudinal plane (P) of the aircraft A. The terms "right" and "left" are to be understood with reference to a usual direction of advance of the aircraft A (i.e. forward). The arrow F to the left in [Fig.2] indicates the usual direction of advance of the aircraft A.

[0033] The first lander Li and the second lander L2 are here of the retractable type but the invention is applicable to fixed lander.

[0034] The first landing gear Li and the second landing gear L2 each comprise a leg J ​​having a first end articulated on a structure of the aircraft A and, opposite, a second end carrying an axle E. Each axle E is provided with two wheels Ru, Ri 2, R21, R2 2 each comprising a rim connected by a web to a hub mounted to rotate on the axle E around an axis X by means of bearings. The rim here comprises two half-rims which are assembled by bolts and which each comprise a bead in such a way that a tire can be trapped between the beads.

[0035] The wheels Ru, Ri 2, R2b R22 of the first and second landing gears Lb L2 are said to be "braked", that is to say equipped with a brake 1 intended to slow down or even stop the aircraft A when it is on the ground. The following description relates to one of the wheels Ru, Ri 2, R21, R2.2- The wheels RL1, Ri 2, R2 b R2 2 are identical here but can also be different.

[0036] With reference to Figures 3A and 3B, the brake 1 of the wheel Ru, Ri 2, R2 b R22 comprises, in a manner known per se, stator discs 2a and rotor discs 2b which are stacked alternately against each other on a torque tube 3 fixed to a collar of the axle E. The stator discs 2a and the rotor discs 2b form a stack of friction discs extending inside an annular space delimited by the wheel Ru, Ri 2, R21, R22.

[0037] The stator discs 2a comprise axial peripheral notches each receiving a section of a tenon which is attached to an outer surface of the torsion tube 3 to ensure rotational coupling of the stator discs 2a with the torsion tube 3 around the axis X.

[0038] The rotor discs 2b comprise axial peripheral notches each receiving a section of a bar which is attached to an inner surface of the rim of the wheel Ru, Ri 2, R2 b R2 2 to ensure rotational coupling of the rotor discs 2b with said wheel Ru, Ri 2, R2b R22 around the axis X.

[0039] The brake 1 also comprises actuators 4 (here six in number) which are controlled by an electronic braking control unit U of the aircraft A and which are carried by an actuator-carrying crown 5 fixed to one end of the torque tube 3. The actuators 4 are here hydraulic and have central axes, parallel to each other, inscribed on the same circle whose center is located on the axis X of rotation of the wheel Ru, Ri 2, R21, R22-

[0040] Each of the actuators 4 comprises a piston 4.1 received in a cylindrical cavity 5.1 of the actuator-carrying ring 5. The cavities 5.1 are distributed equally around the axis X of rotation of the wheel Ru, Ri 2, R21, R22. The pistons 4.1 are movable in translation along an axis parallel to the axis X of rotation of the wheel Ru, Ri 2, R2 i, R22 so as to exert a sufficient pressing force on the stack of disks 2a, 2b to force all of the stator disks 2a and the rotor disks 2b to rub against each other and thus generate a braking torque on the rotor disks 2b.

[0041] The friction of the stator discs 2a and the rotor discs 2b causes an increase in the temperature of said stator discs 2a and said rotor discs 2b, but also wear of their friction faces and therefore a reduction in their thickness. Part of the kinetic energy of the aircraft A is thus dissipated as heat.

[0042] The stator discs 2a and the rotor discs 2b are here made of a carbon-carbon composite material whose frictional wear is all the more significant as its temperature is high.

[0043] The wheel Ru, Ri 2, R21, R22 is equipped with a heat shield 6 interposed between the inner surface of the rim and the stack of discs 2a, 2b to protect the rim and the tire carried by said rim from this influx of heat. The heat shield 6 extends axially projecting from the rim and is here made up of several very thin metal sheets separated by a thin layer of air.

[0044] All this is well known and is only recalled to situate the invention.

[0045] The brake 1 also comprises a temperature sensor 7 arranged to deliver a signal representative of a temperature Tu, T12, T21, T22 of the stack of discs 2a, 2b of the wheel Ru, Ri 2, R21, R22 to the electronic control unit U of the aircraft A.

[0046] The temperature sensor 7 is here a non-contact temperature probe comprising an infrared thermocouple, but can also be of another nature: RTD resistance (from the English “Resistance Temperature Detector”), thermistors, etc. The connection between the temperature sensor 7 and the electronic control unit U can be wired or wireless.

[0047] As illustrated in Figures 3A and 3B, four different positions Pb P2, P3, P4 of the temperature sensor 7 are envisaged here. The temperature sensor 7 is arranged: - on the actuator-carrying ring 5 of the brake 1, the temperature sensor 7 extending between two neighboring actuators 4 along an axis parallel to the axis X of rotation of the wheel Ru, Ri 2, R21, R22, projecting from a front surface of the actuator-carrying ring 5 and facing the first stator disc 2a of the stack of discs (position Pi); or - on the rim or the heat shield 6 of the wheel Ru, Ri 2, R21, R2 2, the temperature sensor 7 extending radially projecting from an internal surface of the rim or the heat shield 6, opposite the first stator disc 2a (positions P21 and P2 2); or - on the rim or in the heat shield 6 of the wheel Ru, Ri 2, R21, R2 2, the temperature sensor 7 extending radially projecting from an internal surface of the rim or the heat shield 6, opposite one of the stator discs 2a of the stack of discs, with the exception of the first stator disc 2a (position P3); or - on the torsion tube 3, the temperature sensor 7 extending radially projecting from an external surface of the torsion tube 3, opposite one of the rotor discs 2b of the stack of discs (position P4).

[0048] The temperature sensor 7 and the stack of discs 2a, 2b are separated by a sufficient distance to protect said temperature sensor 7 from the heat released by the brake 1 while ensuring a direct and precise reading of the temperature Tj.i, T[ 2, T2.b T 2 2 of the stack of discs 2a, 2b with little latency.

[0049] The temperature sensor 7 may be equipped with a shield arranged to protect said temperature sensor 7 from the heat released by the brake 1, and / or a deflector arranged to protect said temperature sensor 7 from dust and braking residues.

[0050] The electronic control unit U is connected to a rudder bar comprising a first right pedal Pi and a second left pedal P2 moved independently of each other by the feet of the pilot of the aircraft A. The first pedal Pi makes it possible to control, via the electronic control unit U, the brakes 1 of the wheels Ru, Ri 2 of the first landing gear Li (independently of those of the second landing gear L2). The second pedal P2 makes it possible to control, via the electronic control unit U, the brakes 1 of the wheels R21, R2 2 of the second landing gear L2 (independently of those of the first landing gear LJ.

[0051] The electronic control unit U is also arranged to receive a signal representative of a forward speed V of the aircraft A (for example delivered by an inertial unit or an on-board GPS) or at the very least to estimate the forward speed V of the aircraft A from several signals (for example delivered by tachometers measuring the rotation speeds of the wheels Ru, Ri 2, R2b R22).

[0052] In order to space out the maintenance of the brakes 1 of the wheels Ru, Ri 2, R2b R22 of the aircraft A, the electronic control unit U is arranged to implement a method to limit the wear of the stator discs 2a and the rotor discs 2b caused by the use of the brakes 1, in particular during the taxiing phases.

[0053] With reference to [Fig.5], the different stages of the process will now be detailed.

[0054] When the speed V of the aircraft A is lower than a predetermined speed here equal to 20 knots, and the pilot presses the first pedal Pb, the electronic control unit U first proceeds, via the temperature sensors 7, to acquire the temperatures Tu, TL2 of the brakes 1 of the wheels Ru, Ri 2 of the first landing gear Lb and then determines which of said brakes 1 has the lowest temperature and then proceeds to activate it to slow down the aircraft A.

[0055] Similarly, when the speed V of the aircraft A is lower than the predetermined speed and the pilot presses the second pedal P2, the electronic control unit U firstly proceeds, via the temperature sensors 7, to acquire the temperatures T2.b T22 of the brakes 1 of the wheels R2b R22 of the second landing gear L2, then determines which of said brakes 1 has the lowest temperature and then proceeds to activate it to slow down the aircraft A.

[0056] In the example illustrated in [Fig.4]: - the temperature Tu of brake 1 of wheel Ru is equal to 354°C (degrees Celsius); - the temperature TL2 of brake 1 of wheel Ru is equal to 316°C; - the temperature T21 of brake 1 of wheel R21 is equal to 366°C; and - the temperature T2 2 of brake 1 of wheel R22 is equal to 301°C.

[0057] Therefore, when the speed V of the aircraft A is lower than the predetermined speed and the pilot presses the first pedal PH the electronic control unit U activates brake 1 of wheel Ri 2 and not that of wheel Ru: the temperature TL2 of brake 1 of wheel Ri 2 is lower than the temperature Tu of brake 1 of wheel Ru.

[0058] Similarly, when the speed V of the aircraft A is lower than the predetermined speed and the pilot presses the second pedal P2, the electronic control unit U activates the brake 1 of the wheel R22 and not that of the wheel R21: the temperature T2 2 of the brake 1 of the wheel R22 is lower than the temperature T21 of the brake 1 of the wheel R 2.1-

[0059] It is understood that when the speed V of the aircraft A is lower than the predetermined speed and the pilot simultaneously presses the first pedal Pi and the second pedal P2, the electronic control unit U simultaneously activates the brakes 1 of the wheels Ri 2, R22 and not those of the wheels Ru, R21: the entirety of the brakes 1 is thus not used when the speed V of the aircraft A is lower than the predetermined speed, which makes it possible to significantly improve the longevity of the stator discs 2a and the rotor discs 2b of the brakes 1 of the aircraft A.

[0060] In the case where the stator discs 2a and the rotor discs 2b are made of a carbon-carbon composite material whose wear by friction is all the more important as its temperature is low, the electronic control unit U will determine the brakes 1 whose temperature is the highest and then proceed to activate them to slow down the aircraft A. More precisely, in the example illustrated in [Fig.4], the electronic control unit U will activate the brakes 1 of the wheels Ru, R21 and not those of the wheels Ri 2, R22.

[0061] Figures 6A and 6B illustrate an aircraft A' which is none other than a first variant of the aircraft A. The aircraft A' differs from the aircraft A in that it comprises a first main landing gear Lf and a second main landing gear L2' which each comprise a first axle E / and a second axle E2', each axle E / , E2' carrying two wheels Ru', R12', R13', R14', R21', R22', R23', R24'.

[0062] The wheels Ru', ... R[4', R2.i', ... R24' are, as for the aircraft A, equipped with a brake 1 to slow down or even stop the aircraft A' when it is on the ground. The brake 1 comprises a temperature sensor 7 arranged to deliver a signal representative of a temperature Tu', TL2', TL3', Ti.4', T2.i', T22', T23', T24' of the stack of discs 2a, 2b of the wheel Ru', ... R[4', R2.i', ... R24' to the electronic braking control unit U of the aircraft A'.

[0063] The electronic control unit U is also arranged to receive a signal representative of a speed V' of advancement of the aircraft A'.

[0064] When the speed V' of the aircraft A' is lower than a predetermined speed here equal to 20 knots, and the pilot presses the first pedal Pb, the electronic control unit U first proceeds, via the temperature sensors 7, to acquire the temperatures Tu', ... TL4' of the brakes 1 of the wheels Ru', ... R[4' of the first landing gear Lf, then determines for each axle Ef, E2' the brake 1 having the lowest temperature and then proceeds to activate it to slow down the aircraft A'.

[0065] Similarly, when the speed V' of the aircraft A' is lower than the predetermined speed and the pilot presses the second pedal P2, the electronic control unit U first proceeds, via the temperature sensors 7, to acquire the temperatures T24', ... T24' of the brakes 1 of the wheels R2[', ... R24' of the second landing gear L2', then determines for each axle Ef, E2' the brake 1 having the lowest temperature and then proceeds to activate it to slow down the aircraft A'.

[0066] In the example illustrated in [Fig.6B]: the temperature Tu' of brake 1 of wheel Ru' is equal to 166°C; the temperature TL2' of brake 1 of wheel Ri 2' is equal to 212°C; the temperature TL3' of brake 1 of wheel Ri 3' is equal to 255°C; the temperature TL4' of brake 1 of wheel Ri 4' is equal to 253°C; the temperature T2.i' of brake 1 of wheel R21' is equal to 267°C; - the temperature T2.2' of brake 1 of wheel R22' is equal to 211°C; - the temperature T2 3' of brake 1 of wheel R23' is equal to 255°C; and - the temperature T24' of brake 1 of wheel R24' is equal to 207°C.

[0067] Therefore, when the speed V' of the aircraft A' is lower than the predetermined speed completed and the pilot presses the first pedal Pb the electronic control unit U activates the brake 1 of the wheels Ru', R[4', and not those of the wheels Ri 2', RL3'.

[0068] Similarly, when the speed V' of the aircraft A' is lower than the predetermined speed and the pilot presses the second pedal P2, the electronic control unit U activates the brake 1 of the wheels R22', R24', and not those of the wheels R21', R23'.

[0069] It is understood that when the speed V' of the aircraft A' is lower than the predetermined speed and the pilot simultaneously presses the first pedal Pi and the second pedal P2, the electronic control unit U simultaneously activates the brakes 1 of the wheels Ru', R[4', R22', R24' and not those of the wheels Ri 2', Ri 3', Ru', R23': all of the brakes 1 are thus not used when the speed V' of the aircraft A' is lower than the predetermined speed, which makes it possible to significantly improve the longevity of the stator discs 2a and the rotor discs 2b of the brakes 1 of the aircraft A'.

[0070] In the case where the stator discs 2a and the rotor discs 2b are made of a carbon-carbon composite material whose frictional wear is all the more significant as its temperature is low, then the electronic control unit U will determine the brakes 1 whose temperature is the highest and then proceed to activate them to slow down the aircraft A'. More precisely, in the example illustrated in [Fig.6B], the electronic control unit U will activate the brakes 1 of the wheels Ri 2', Ri 3', Ru', R23' and not those of the wheels Ru', RL4', R22', R24'.

[0071] Figures 7A and 7B illustrate an aircraft A” which is none other than a second variant of the aircraft A. The aircraft A” differs from the aircraft A in that it comprises a first main landing gear Li” and a second main landing gear L2” each comprising a first axle Ei”, a second axle E2” and a third axle E3”. Each axle Ei”, E2”, E3” carries two wheels Ru”, Ri.2”, Ri.3”, Ri4”, R 1.5 , Ri 6 » R2 1 » R2 2 » R2 3 » R2 4 » R2 5 » R2 6 •

[0072] The wheels Ri 1”, ... R16”, R21”, ... R26” are, as for the aircraft A, equipped with a brake 1 to slow down or even stop the aircraft A” when it is on the ground. The brake 1 comprises a temperature sensor 7 arranged to deliver a signal representative of a temperature Tu”, TL2”, TL3”, TL4”, Tu”, TL6”, Tu”, T22”, T23”, T24”, T2.5”, T26” of the stack of discs 2a, 2b of the wheels Ru”, ... Ri.6”, Ru”, R2.6” to the electronic braking control unit U of the aircraft A”.

[0073] The electronic control unit U is also arranged to receive a signal representative of a speed V” of advancement of the aircraft A”.

[0074] When the speed V” of the aircraft A” is lower than a predetermined speed here equal to 20 knots, and the pilot presses the first pedal Ph, the electronic control unit U first proceeds, via the temperature sensors 7, to acquire the temperatures Tu”, ... TL6” of the brakes 1 of the wheels Ru”, ... Ri,6” of the first landing gear Li”, then determines for each axle Ei”, E2”, E3” the brake 1 having the lowest temperature and then proceeds to activate it to slow down the aircraft A”.

[0075] Similarly, when the speed V” of the aircraft A” is lower than the predetermined speed and the pilot presses the second pedal P2, the electronic control unit U first proceeds, via the temperature sensors 7, to acquire the temperatures T2.i”, ... T2.6” of the brakes 1 of the wheels R2i”, ... R26” of the second landing gear L2”, then determines for each axle Ei”, E2”, E3” the brake 1 having the lowest temperature and then proceeds to activate it to slow down the aircraft A”.

[0076] In the example illustrated in [Fig.7B]: - the temperature Tu ” of brake 1 of wheel Rn” is equal to 207°C; - the temperature TL2' of brake 1 of wheel Ri 2” is equal to 190°C; - the temperature Ti,3” of brake 1 of wheel Ri 3” is equal to 165°C; - the temperature TL4' ' of brake 1 of wheel Ri 4' ' is equal to 212°C; - the temperature Ti,5' ' of the brake 1 of the wheel Ri 5' ' is equal to 255°C; - the temperature TL6' ' of brake 1 of wheel Ri 6' ' is equal to 253°C; - the temperature T21” of brake 1 of wheel R21” is equal to 243°C; - the temperature T2 2” of brake 1 of wheel R22” is equal to 197°C; - the temperature T23'' of brake 1 of wheel R2 3'' is equal to 267°C; - the temperature T2 4' ' of brake 1 of wheel R2 4' ' is equal to 211°C; - the temperature T2 5' ' of brake 1 of wheel R2 5' ' is equal to 255°C; and - the temperature T26' ' of brake 1 of wheel R2 6' ' is equal to 207°C.

[0077] Therefore, when the speed V” of the aircraft A” is lower than the predetermined speed and the pilot presses the first pedal Pb, the electronic control unit U activates the brake 1 of the wheels Ri2”, R[3”, Ri,6” and not those of the wheels Ru”, R14 ”, Ri.5”•

[0078] Similarly, when the speed V” of the aircraft A” is lower than the predetermined speed and the pilot presses the second pedal P2, the electronic control unit U activates the brake 1 of the wheels R22”, R24”, R2.6” and not those of the wheels R2i”, R2 3 , R2 5 •

[0079] It is understood that when the speed V” of the aircraft A” is lower than the predetermined speed and the pilot simultaneously presses the first pedal Pi and the second pedal P2, the electronic control unit U simultaneously activates the brakes 1 of the wheels Ri2”, R1.3”, Ri / ', R22 ”, R2 / ', R2 / ' and not those of the wheels Ru”, R 1.4”, R1.5”, R2.1”, R2.3”, R2 / ': the entirety of the brakes 1 is thus not used when the speed V” of the aircraft A” is lower than the predetermined speed, which makes it possible to significantly improve the longevity of the stator discs 2a and the rotor discs 2b of the brakes 1 of the aircraft A”.

[0080] In the case where the stator discs 2a and the rotor discs 2b are made of a carbon-carbon composite material whose frictional wear is all the more significant as its temperature is low, then the electronic control unit U will determine the brakes 1 whose temperature is the highest and then proceed to activate them to slow down the aircraft A”. More precisely, in the example illustrated in [Fig.7B], the electronic control unit U will activate the brakes 1 of the wheels Ru”, RL4 ”, Ri5”, R2.1”, R2.3”, R2.5” and not those of the wheels RL2”, R1.3”, Ri / ', R2.2”, R2.4”, R2.6 9 9

[0081] 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.

[0082] Although here the method of the invention is applied here to the two axles Ef, E2' of the landing gears Lf, L2' of the aircraft A', it can be applied to only one of the two axles E!', E2'.

[0083] Although here the method of the invention is applied here to the three axles Ei”, E2”, E3 ” of the landing gears Li”, L2” of the aircraft A”, it can be applied to only one or two of the axles Ei”, E2”, E3”.

[0084] Although the actuators 4 are hydraulic here, they can be electric, pneumatic, etc.

[0085] Although the stator discs 2a and the rotor discs 2b are here made of a carbon-carbon composite material, they can be made of another material.

[0086] Although the predetermined speed is here equal to 20 knots, it may be different and for example be between 15 knots and 25 knots.

Claims

Claims

1. Method for limiting the wear of discs (2a, 2b) of brakes (1) of two braked wheels (Ru, R12, R21, R22; R1.1', • •• R1.4', R2.1', ••• R2.4'; R1.1 ”, ••• R1.6 ”, R2.1”, ... R2.6”) mounted for rotation on an axle of a landing gear (Lb L2; Lf, L2'; Li”, L2”) of an aircraft (A; A'; A”), the method comprising, when the aircraft is rolling at a speed (V; V'; V”) lower than a predetermined speed and a pilot of said aircraft actuates the brake of the wheels of the landing gear, the following steps: • acquisition of a temperature (Tu, T1.2, T2.i, T2.2; Tu', ... T1.4 ', T2.1', ... T2.4'; T1.1”, ... TL6”, T2.i”, ... T2.6”) of the brake discs of each of the two wheels; • determination of the wheel whose brake has the lowest or highest temperature; • activation of the brake with the lowest or highest temperature depending on the material from which the brake discs are made.

2. The method of claim 1 wherein the predetermined speed is between 15 knots and 25 knots.

3. A method according to claim 2 wherein the predetermined speed is equal to 20 knots.

4. Aircraft (A; A'; A”) comprising: • a first main landing gear (Li; Lf; Li”) and a second main landing gear (L2; L2'; L2”) each comprising at least one axle (E; Ef, E2'; Ef', E2”, E3”) provided with two wheels (Ru, R[ 2, R2.1, R22; R1.1', ••• Ri4,R2i”, ... R2.4'; Ru”, ... Ri / ', R2.1”, ••• R2.6”), each of the wheels being equipped with a brake (1) comprising brake discs (2a, 2b), • an electronic brake control unit (U) connected to temperature sensors (7) of the wheel brakes, and receiving a signal representative of a forward speed (V) of the aircraft, the electronic control unit (U) being arranged to implement the method according to any one of the preceding claims for each of the axles.

Images