System for ventilating the brakes and the taxiing motor of an aircraft wheel and wheel assembly comprising such a system

Abstract

One aspect of the invention relates to a ventilation system (9) for ventilating the braking device of an aircraft wheel and optionally an electric taxiing motor, which comprises a ventilation wheel (12), an electric motor (10) for rotating the ventilation wheel, and an epicyclic reduction gear (13) interposed between the rotating shaft (11) of the electric motor and the ventilation wheel. The epicyclic reduction gear preferably comprises a sun gear (20) integral with the rotating shaft, planet gears with fixed planet carriers, and a rotating ring gear (23) integral with the ventilation wheel.

Description

Aircraft wheel brake and taxiing motor ventilation system and wheel assembly comprising such a system TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a ventilation cooling system for an aircraft wheel, intended to cool the braking device of this wheel, as well as the electric taxiing motor of this wheel when it is equipped with one.

[0002] The invention also relates to a wheel assembly comprising a braking device and possibly an electric taxiing motor, cooled by such a ventilation system.

[0003] The invention finds applications in the field of aircraft landing gear. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0004] Aircraft landing gear typically consists of several wheels, each equipped with a braking device. However, these braking devices heat up when activated. Aircraft wheel braking devices, in particular, become very hot during landing, due to the aircraft's speed upon reaching the ground and its mass.

[0005] Not only can this heating pose a risk to the integrity of the braking system, but it also has an effect on the aircraft's profitability. Indeed, the rotation time of an aircraft, i.e. the time it must remain on the ground before being able to take off again, is conditioned by the cooling of the landing gear braking systems. An aircraft cannot leave its parking point while the brake discs are too hot, which could lead to a risk of breakage in the event of a takeoff cancellation. However, the longer the rotation time of an aircraft, the less profitable the aircraft is.

[0006] To limit aircraft rotation time, it is known to place a fan on the ground, near the aircraft's wheels. It is also known to use an on-board forced ventilation system. This forced ventilation system is generally housed within the landing gear.

[0007] Aircraft wheel ventilation systems are thus known, specifically dedicated to cooling the braking devices of landing gear. Such systems usually comprise a BCF type fan (acronym derived from the English expression "Brake Cooling Fan") with a ventilation wheel located on the outside of the rim, driven by a motor and configured to suck in a flow of air from the brake outlet and mix it with the outside air in order to cool the brakes.

[0008] However, these known ventilation systems are relatively heavy and bulky, which poses space problems for aircraft landing gear.

[0009] 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 to both new aircraft types and those already 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.

[0010] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. 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 consequences with the aim of improving the energy efficiency of aircraft.

[0011] Consequently, the Applicant is constantly working to reduce its negative 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.

[0012] 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.

[0013] With this in mind, the applicant has developed so-called electric taxiing systems which enable the rotation of the wheels of the aircraft's landing gear to be driven by means of an electric taxiing motor to move the aircraft forward when it is moving on the ground, without using the conventional turbomachine propulsion system used during the flight phase.

[0014] However, these systems, and in particular their electric motors, are also located at the aircraft's wheels, which increases the space requirement there. It is therefore even more complicated to install an on-board ventilation system for aircraft wheels in this restricted environment.

[0015] However, the taxiing motor also causes localized heating when operating, and therefore also requires dedicated cooling.

[0016] There is therefore a real need for an on-board ventilation system, sufficiently compact and miniaturized to be able to be installed in the restricted environment of a landing gear wheel, while being efficient enough to satisfactorily cool both the braking device of this wheel and the taxiing motor if the wheel is equipped with one. SUMMARY OF THE INVENTION

[0017] The invention aims to meet this unmet need.

[0018] For this, a first aspect of the invention teaches a ventilation system for a braking device of an aircraft wheel. This ventilation system comprises a ventilation wheel and an electric motor for driving the ventilation wheel in rotation, said motor comprising a rotating shaft.

[0019] According to the invention, said ventilation system further comprises an epicyclic reducer interposed between the rotating shaft of the electric motor and the ventilation wheel.

[0020] Thanks to this new architecture, the ventilation system according to the invention can advantageously be miniaturized and placed in a particularly restricted and cluttered environment.

[0021] Indeed, even if the electric motor is chosen to be small and therefore with a shaft rotating very quickly and developing only a low torque, the addition of a reducer allows the rotation speed to be reduced and the resulting torque to be increased in order to obtain satisfactory rotation of the ventilation wheel, which remains of sufficient size to ensure efficient and correctly localized ventilation.

[0022] The ventilation system of the invention can thus be directly installed in the heart of a wheel of the aircraft, its ventilation wheel remaining outside the rim, while the motor and reducer assembly, also called a motor-reducer assembly, can advantageously be housed inside the axle of the aircraft wheel, in the latter's spindle. The space located around the axle of the aircraft wheel can then be reserved for the elements of the braking device and the electric motor of the taxiing system.

[0023] In addition, the use of an epicyclic gearbox allows for a large reduction ratio while remaining extremely compact. Since the load is distributed across several planetary gears, high efficiency can be achieved with a limited footprint.

[0024] Advantageously, the epicyclic reducer comprises a sun gear connected to the rotating shaft, satellites with a fixed planet carrier and a rotating crown connected to the ventilation wheel.

[0025] Advantageously, this solar is integral with the rotating shaft. It can therefore, for example, be directly fixed to the end of the rotating shaft of the motor, which increases the compactness of the assembly.

[0026] Advantageously, the rotating crown is integral with the ventilation wheel, which makes it possible to limit the number of bearings and increase the compactness of the assembly. In addition, this improves the mechanical strength of the ventilation wheel and its guidance during its rotation. Indeed, the mechanical assembly between the rotating crown and the ventilation wheel is better, due to the larger contact surface area that exists between the two parts which rotate at the same speed.

[0027] In this application, two elements are said to be "integral" with each other if they are made from a single piece or are directly fixed to each other, so as to move together in a common movement. They can thus, for example, be welded, glued, screwed or clipped to each other.

[0028] Advantageously, the epicyclic reducer can, for example, have a ratio of 5. This preferred ratio allows optimal miniaturization of the geared motor assembly, allowing it to be integrated into the spindle of a conventional aircraft wheel, while guaranteeing sufficient speed to obtain the necessary ventilation.

[0029] Advantageously, the ventilation system according to the invention may further comprise a casing in which the electric motor and the epicyclic reduction gear are housed. This casing advantageously protects the geared motor assembly by insulating it from the outside and in particular from water, frost, dust, braking residues, etc. In addition, thanks to this casing, which is preferably sealed, the gears of the epicyclic gear train can be greased for life, which limits maintenance operations and increases the service life of the assembly.

[0030] Advantageously, the ventilation system according to the invention may further comprise a protective grille for the ventilation wheel. This grille protects the ventilation wheel from the entry of dust or debris likely to damage it. It also has the function of protecting operators by preventing any contact, for example of a finger or a tool, with the ventilation wheel which rotates very quickly while the aircraft is on the ground.

[0031] A second aspect of the invention relates to an aircraft wheel assembly comprising a wheel mounted on an axle, a device for braking said wheel and a ventilation system as described above.

[0032] Advantageously, in this wheel assembly, the motor and the reducer can be arranged in the axle of the wheel, preferably in the spindle of this wheel.

[0033] Advantageously, this wheel assembly can also include an electric taxiing motor.

[0034] A third aspect of the invention relates to an aircraft landing gear which comprises at least one wheel assembly as described above.

[0035] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0036] The figures are presented for information purposes only and in no way limit the invention.

[0037] [Fig. 1] is a schematic sectional view of an example of a wheel assembly according to the invention.

[0038] [Fig. 2] is an exploded perspective view of an exemplary ventilation system according to the invention.

[0039] [Fig. 3] is an exploded perspective view of the geared motor assembly of the ventilation system of Figure 2.

[0040] [Fig. 4] is a schematic cross-sectional view of the epicyclic reducer of the ventilation system of Figure 2.

[0041] [Fig. 5] is a perspective view of the ventilation system of Figure 2 to which a protective grille has been added in exploded view. DETAILED DESCRIPTION

[0042] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0043] In Figure 1, a schematic example of a wheel assembly 1 according to the invention is shown. This wheel assembly 1 comprises a wheel 2, of which only the rim 3 has been shown and which belongs to a landing gear 4 of an aircraft. This wheel 2 is mounted on an axle 5, of geometric axis XX, the end of which forms the spindle 6 of the wheel 2.

[0044] This wheel 2 is equipped with a braking device 7, located on the axle 5 on the inner side of the rim 3, and an electric taxiing system whose taxiing motor 8 is also placed on the axle 5, but on the outer side of the rim 3. The space surrounding the spindle 6 of the wheel 2 is therefore particularly cluttered.

[0045] According to the invention, the wheel assembly 1 also comprises a ventilation system 9 for the braking device. Advantageously, this ventilation system 9 also makes it possible to cool the taxiing motor 8.

[0046] The ventilation system 9 comprises an electric motor 10 whose rotating shaft 11 is coupled with a ventilation wheel 12 to drive it in rotation.

[0047] According to the invention, the ventilation system 9 also comprises an epicyclic reducer 13, interposed between the electric motor 10 and the ventilation wheel 12, which makes it possible to transmit to the ventilation wheel 12 an increased torque and a reduced rotation speed compared to that of the rotating shaft 11 at the output of the motor 10.

[0048] The assembly formed by the electric motor 10 and the epicyclic reduction gear 13 is called the geared motor assembly 14 and is preferably arranged in the axle 5 of the wheel 2, inside the rocket 6. It therefore does not generate any additional bulk and can be perfectly integrated into the landing gear. In this case, the ventilation system 9 is also of geometric axis XX, that is to say it is coaxial with the axle 5, in order to avoid any imbalance problem.

[0049] This geared motor assembly 14 is advantageously housed in a sealed casing 15 in order to protect it from the external environment and to guarantee optimal lubrication of its elements.

[0050] The geared motor assembly 14 may be connected to the ventilation wheel 12 by means of a mechanical shaft 16 as shown in FIG. 1, or preferably be directly fixed against it as shown in FIG. 5.

[0051] The ventilation wheel 12 is arranged on the outer side of the wheel assembly 1, i.e. on the outer side of the rim 2 and after the taxiing motor 8 if the wheel assembly 1 has one.

[0052] The ventilation wheel 12 shown comprises a solid central disc 17, at the periphery of which extend a plurality of radial blades 18 which, when rotating, generate a flow of ventilation air.

[0053] These blades 18 are located in front of the air stream which surrounds the braking device 7 and the taxiing motor 8. Their rotation thus advantageously creates a suction which causes the mixing of a flow of hot air F1 coming from the braking device through the rim 3 with a flow of fresh air F2 coming from outside the wheel assembly 1, and which, by escaping, also allows the taxiing motor 8 to be cooled.

[0054] Advantageously, the solid central disc 17 provides better mechanical strength to the ventilation wheel 12 and limits pressure losses.

[0055] A preferred embodiment of the ventilation system 9 is shown in Figures 2 to 5.

[0056] The casing 15 serves as a support for the electric motor 10 which is powered by a connector 19 electrically connected to the aircraft's electrical network.

[0057] Different configurations of epicyclic reducer 13 can be used, including single or double, flat or spherical gear sets, with fixed planet carriers and rotating crown, with free planet carriers and fixed crown, etc.

[0058] The preferred epicyclic reducer 13 shown is a simple, flat epicyclic gear train with fixed planet carriers and rotating crown. It comprises a sun gear 20 connected to the rotating shaft 11 of the electric motor 10, three planet gears 21 with fixed planet carriers 22 and a rotating crown gear 23 connected to the ventilation wheel 12.

[0059] Advantageously, the solar 20 can be directly mounted on the rotating shaft 11 and the crown 23 can be directly fixed on the ventilation wheel 12. This results in a better compactness of the assembly, a reduction in the number of bearings required and better mechanical strength of the ventilation wheel 12 with better guidance in rotation thereof.

[0060] For this purpose, the crown 23 can be made in one piece with the ventilation wheel 12 or be fixed thereto by any suitable means. As shown, it can for example be screwed onto the central disc 17 by means of a set of screws 24.

[0061] According to a particular embodiment, this epicyclic reducer 13 can have a ratio of 5, with the following characteristics: at the power input, a 16-tooth solar 20, secured to the rotating shaft 11 of the electric motor 10, with a rotation speed of 11,500 rpm; three 32-tooth satellites 21, with fixed planet carriers 22, with a rotation speed of 5,750 rpm; and at the power output, a rotating 80-tooth crown 23, secured to the ventilation wheel 12, with a rotation speed of 2,300 rpm.

[0062] The ventilation wheel 12 thus rotates at the same speed as the rotating crown 23 which drives it in rotation.

[0063] Finally, a protective grid 25, which is in the form of a disc 26 perforated at the periphery in the example shown, is preferably added to the outer side of the ventilation wheel 12.

Claims

CLAIMS

1. Ventilation system (9) of a braking device (7) of an aircraft wheel (2), comprising: - a ventilation wheel (12) and - an electric motor (10) for driving the ventilation wheel (12) in rotation, said electric motor (10) comprising a rotating shaft (11), said ventilation system (9) being characterized in that it further comprises an epicyclic reducer (13) interposed between the rotating shaft (11) and the ventilation wheel (12), and in that the epicyclic reducer (13) comprises a sun gear (20) secured to the rotating shaft (11), satellites (21) with a fixed planet carrier (22) and a rotating crown (23) secured to the ventilation wheel (12).

2. Ventilation system (9) according to the preceding claim, characterized in that it further comprises a casing (15) in which the electric motor (10) and the epicyclic reducer (13) are housed.

3. Ventilation system (9) according to one of the preceding claims, characterized in that it further comprises a grille (25) for protecting the ventilation wheel (12).

4. Aircraft wheel assembly (1) comprising a wheel (2) mounted on an axle (5), a braking device (7) for said wheel (2) and a ventilation system for the braking device (7), characterized in that the ventilation system for the braking device (7) is a ventilation system (9) according to one of the preceding claims.

5. Wheel assembly (1) according to claim 4 characterized in that the motor (10) and the reducer (13) are arranged in the axle (5) of the wheel (2).

6. Wheel assembly (1) according to claim 4 or 5 characterized in that the motor (10) and the reducer (13) are arranged in the spindle (6) of the wheel (2).

7. Wheel assembly (1) according to one of claims 4 to 6, characterized in that it further comprises an electric taxiing motor (8).

8. Aircraft landing gear (4) characterized in that it comprises at least one wheel assembly (1) according to one of claims 4 to 7.

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