WO2009141554A2

WO2009141554A2 - Anciliary device for taxiing along the ground an aircraft with a turbomachine

Info

Publication number: WO2009141554A2
Application number: PCT/FR2009/050819
Authority: WO
Inventors: Guillaume Bulin; Claire Leve; Juluan Gaultier; Christophe Cros
Original assignee: Airbus France; Airbus Sas
Priority date: 2008-05-05
Filing date: 2009-05-05
Publication date: 2009-11-26
Also published as: FR2930759B1; FR2930759A1; WO2009141554A3

Abstract

- The subject of the invention is device for driving at least one wheel (22) of an aircraft landing gear which comprises at least one turbine machine (1) incorporated into the landing gear of the aircraft and which is designed to move the aircraft along the ground at low speed. The turbine machine (1) is preferably a turbomachine comprising a combustion chamber (3) in communication with an axial turbine stage (4) that drives a compression stage (2).

Description

APPARATUS FOR DISPLACING THE GROUND OF AN AIR VEHICLE

AT TURBOMACHINE

The present invention relates to an ancillary device for the ground movement of an air vehicle and more particularly to a device consisting of an integrated system for moving an air vehicle adapted to the traction of the vehicle on the ground. It applies in particular to commercial aircraft equipped with turbojets.

In general, the taxiing phase of commercial aircraft on the ground is carried out thanks to the thrust of at least one of the main engines of the aircraft, and / or by towing the aircraft by means of a track tractor. . The rolling of an airplane can be divided into two phases. the first phase is the so-called "taxi out" phase, ie the phase in which the aircraft moves from the passenger boarding gate to the threshold of the runway in order to take off:

During this phase the aircraft leaves the terminal pushed backwards by means of a track tractor and one or more of its main engines are then lit.

Once the aircraft is sufficiently far from the terminal and positioned to move forward, the tractor is disconnected, the aircraft then moves at low speed using the thrust of one or more of its main engines, since the terminal to the threshold of the runway. The aircraft is then controlled by the pilot from the cockpit via the steering unit.

The second phase is the so-called "taxi-in" phase, ie the phase in which the aircraft is heading after landing from the runway to the terminal: In this phase, after having landed, the aircraft moves at a low speed from the airstrip to the terminal by the thrust of one or more of its main engines, under the control of the pilot in the cockpit, via the Control unit. When approaching the terminal, the maneuvering of the aircraft may be guided by runway personnel and, in case of congested traffic, the aircraft may stop before the terminal and then be driven by a track tractor until at the landing gate.

Running the aircraft according to the current procedure is causing significant costs for the airlines.

These costs are primarily related to the use of the reactors for taxiing, because they are sized for the flight phase, and therefore do not operate optimally at low speed and low power, resulting in overconsumption kerosene. Secondly, there is also the additional cost of maintaining and repairing the damage caused by jet blast when the aircraft are too close together, and by the ingestion of debris by the reactors during taxiing.

In addition, using the reactors for taxiing is also a source of noise pollution at the airport, resulting in emissions of particulate pollutants that affect local air quality and contribute to the greenhouse effect. .

In addition, the current procedure makes the aircraft dependent on track tractors for the rear steps because the jet engines of the aircraft generally do not allow to maneuver in reverse. This can lead to delays, when tractors are not available, and costs associated with their use.

It is therefore desirable for companies to reduce their operational costs by optimizing aircraft ground movements. For this, new taxiing procedures must be proposed to reduce kerosene consumption, reduce taxi time and reduce noise emissions and gaseous emissions. The solution proposed by the present invention thus relates to a self-driving system, housed in or near the hubs or wheel rims of the main trains or the front axle of a commercial aircraft.

The device according to the invention is particularly intended for landing gear, front or main, of an airliner equipped with turbojets.

Technical solutions relating to the autonomous running of aircraft exist and in particular the document US 2006/0065779 A1 describes a front axle equipped with at least one wheel axle, at least one wheel coupled to the wheel axle, at least one wheel motor. wheel coupled to the wheel axle and the wheel and a control device connected to the wheel motor and rotating the wheel.

This document envisages as a unique embodiment an electric motor housed in the rim of at least one wheel of the front axle.

This electric motor ensures the taxi function, but also to rotate the wheels of the front axle prior to landing, to minimize tire wear when they touch the track.

The main disadvantage of a motorized electric motorized front-wheel drive system is the use of a system away from the APU (auxiliary generator located at the rear of the aircraft which notably provides electric power when the aircraft is on the ground) which requires the addition of power wiring and therefore the additional mass on board.

In addition, the total mass of an electric propulsion system includes the engine itself, the power wiring, the power converter, the controller and possibly a disengaging mechanism.

The mass of these devices is often high and the fuel consumed by transporting this additional mass (snowball effect) may cancel the fuel economy achieved during the taxi.

The use of the front axle in traction also has the drawback that the mass distributed on the front axle may not be sufficient to allow traction of the aircraft by the front axle: if the traction to be applied is greater than the maximum traction applicable, the wheel skates and the aircraft can not move forward.

According to the document US Pat. No. 3,874,619, a hydraulic device combining a braking system and a particular propulsion system in which the brakes are mounted on jacks ensuring mobility of the aircraft. According to the document US 3,059,712, a hydraulic motor drives, through an endless screw, a crown which is coupled to the rim of a wheel of a landing gear by an inflatable toric element.

The drive of the wheel is made by the hydraulic motor after inflating the inflatable element which allows the drive.

Another embodiment described in document US Pat. No. 3,711,043 is constituted by a hydraulic motor housed in the hub of at least one wheel of at least one main gear of the aircraft. This type of system, like the previous one can not work without the installation of a hydraulic distribution system, which requires a major modification of the hydraulic architecture of the aircraft and has a cost in terms of additional mass on board.

Finally, the document WO 2007/048164 A1 describes an electromagnetic device that can function as a motor and generator placed in the rim of at least one wheel of at least one main gear, which makes it possible to ensure both the driving functions and braking, replacing the carbon brakes that today occupy this space in the rims of the main trains. This type of system proves to be for the moment too heavy and bulky to be mounted advantageously on aircraft.

The object of the present invention is to provide an autonomous taxi system for commercial aircraft, which can be housed near one or more front or main trains, which is simpler and lighter than existing solutions, so that the aircraft can moving on the ground between the terminal and the take-off or landing runway without the aid of its main engines or runway equipment while consuming little fuel during these taxiing phases and without adding significant over-consumption during flight phases.

To do this, the present invention provides a device for driving at least one wheel of a landing gear of an aircraft which comprises at least one turbine machine integrated in the landing gear of the aircraft and which is adapted to move the aircraft on the ground at low speed. Preferably, the turbine machine is a turbomachine comprising a combustion chamber in communication with an axial turbine stage driving a compression stage.

Advantageously, the turbine machine is a micro-turbine. The micro-turbine type turbomachine advantageously comprises a single-flow turbojet, it preferably comprises a compression stage in the form of a centrifugal compressor and / or a free turbine stage driving at least one wheel of the aircraft through means of mechanical transmission.

The mechanical transmission means preferably comprise a clutch system interposed between the turbomachine and said at least one wheel and / or a fixed or variable reducer.

According to a particular embodiment, the mechanical transmission means comprise a device for reversing the direction of rotation of the wheels to allow the autonomous movement of the apparatus in reverse.

The device advantageously comprises means for reducing noise emissions.

It comprises a fuel system comprising a fuel supply line connecting the tanks of the aircraft to the turbomachine and a fuel management system connected to a control cockpit piloting a fuel shutoff valve located on the fuel supply line.

Other characteristics and advantages of the invention will emerge on reading the following description of a nonlimiting exemplary embodiment of the invention with reference to the drawings which show: in FIG. 1: a side view in semi-section a first embodiment of a device according to the invention; in FIG. 2: a perspective view of an example of implantation of a second example of a device according to the invention mounted on a landing gear leg. in Figure 3: a detailed sectional view of a device according to the invention.

As seen above, the invention consists in integrating on one or more parts of a landing gear front or main aircraft one or more turbine machines. These turbine machines are, according to the example of FIG. 1, turbomachines of the micro-turbine type including non-exclusively as shown in FIG. 1 a single-flow turbojet engine with a compression stage 2, the compressor considered being a centrifugal compressor, a combustion chamber 3, an axial turbine stage 4 driving the compression stage 2, a free turbine stage 5, transmission means mechanical devices 6 comprising in known manner for example a fixed or variable reduction device, for example a gearbox consisting of an epicyclic gear train and possibly a clutch system, these transmission means driving in the example of Figure 1 a rim 13 of wheel through gear means 16.

The turbomachine further comprises a fuel system which comprises a fuel line 7 connecting the aircraft tanks to said turbomachine, a fuel supply closing valve 8 located at a point on the fuel line and a fuel system. 9 of fuel management at the turbomachine or at the electric core of the aircraft.

The start of the system is directly controlled by the crew from the cockpit. Indeed, the latter by pressing a button 10 sends an electrical signal to the main controller located in the electric core of the aircraft. This converts the electrical signal into a logic signal sent to the fuel shutoff valve located along the fuel line. The opening of the valve then allows the fuel supply of the turbomachine started by an electric starter 17.

During the phases of taxiing forward at low speed, between the terminal and the runway, the speed of the aircraft is directly controlled by the crew from the cockpit.

In the case of aircraft with electric controls, the crew sends from the cockpit through a control means such as a joystick 11 an electrical signal to the main controller 9 located in the electric heart of the aircraft. It relays the signal to the fuel management system, which regulates the fuel flow to the turbomachine fuel injectors 12.

This flow rate depends on the rotational speed of the axial turbine, and therefore the speed of rotation of the free turbine. The free turbine drives the rotation of one or more of the wheels of the train on which this turbomachine is mounted, by means of the mechanical transmission means 6. Thus, the crew, by controlling from the cockpit the flow of kerosene, control directly the running speed of the aircraft. Other speed regulating devices can be used and in particular a mechanical variator on the output of the turbomachine can make it possible to vary the speed of rotation of the wheels.

An advantage of the turbomachine over electrical systems is that the electrical systems have a low power density compared to other systems. By way of comparison, the mass power of an electric motor is of the order of 0.3 to 1 kW / kg installed whereas that of a turbomachine in the form of a micro-turbine is 2.5 kW / kg installed. In addition, the electrical systems also have a low power density (approximately 1500 kW / m ³ compared to 2500 kW / m ³ for a micro-turbine) and are limited in torque with respect to a turbomachine.

During the taxiing phase, the control of the direction of the aircraft is carried out in the same way as when the aircraft moves thanks to the thrust of its main engines: an electric signal is sent by the pilot from the cockpit, to the controller located in the electric heart of the aircraft. A converter in the electrical heart of the aircraft converts the electrical signal into a logic signal that is sent to the direction control unit of the aircraft located on the nose gear.

The flow control controls, and therefore the speed of the wheels, can be coupled with the steering control on the same control means 11 to roll and direct the aircraft.

During high-speed, take-off and landing phases, the aircraft is propelled by its main engines.

The free turbine 5 is then disengaged from the wheels thanks to the clutch system of the mechanical transmission means 6 and the turbomachine is freewheeling.

According to a particular embodiment, the mechanical transmission system disposed between the turbomachine and the wheels comprises a device for reversing the direction of rotation of the wheels to allow the autonomous movement of the apparatus in reverse.

This device can be for example similar to a gearbox, like the car gearboxes, in the sense that a pinion can be geared between the free turbine wheel and the wheel of the aircraft to add a floor gear and thus reverse the direction of rotation. Other known means of inversion of rotation can be interposed between the turbine and the wheel or wheels.

Advantageously, as shown in FIG. 1, the turbomachine or turbines in the form of micro-turbines may be placed in the hub itself of one or more wheels 22 of the train under consideration. In this way, the wheel or wheels are directly driven by the free turbine through the transmission device here of the planetary gear type and the clutch system.

According to this example, the turbine machine is disposed at the end of the rocket 14 which carries the rim 13 through bearings 15. The drive of the wheel is done by means of a toothing 16 between the rim and the reduction device driving means 6.

In this case, it is not necessary to design a mechanical transmission system other than a planetary gearbox between the free turbine and the wheels. However, any other location of the turbo-machine near the train may be considered, for reasons of space for example by adding motion transmission means such as a transmission shaft.

It should be noted that given the speed of startup of micro-turbines, such a turbine engine can be started by means of the electric starter 17 and stopped at each departure and stop of the aircraft. This limits the operating time of the turbomachine which is favorable to reduce fuel consumption.

In the example of Figure 2, the positioning of the turbine machine 1 is made to allow easy removal of this equipment of the landing gear in case of failure.

This positioning, however, requires a deflection device for connecting the free turbine to the wheel shaft which further becomes a transmission shaft.

FIG. 3 represents the device of the invention in position on a landing gear leg such as a front landing gear leg. According to this example and in the case of a front gear 19, the turbomachine is mounted in front of the landing gear between two wheels 13.

A quick attachment and release device such as the devices already used to attach the starters of the main engines to the accessory box of said engines is advantageously used to position or remove the turbomachine.

Such an attachment device consists of a "quarter firefighter" 23 which takes a portion of the forces induced by the device to maintain and allows its retention in position. Arms 24, 25 connecting to the landing gear support the device.

The motor shaft 26 of the device transmits the motor torque to the wheel shaft 27 through a bevel gear.

The air intake 28 of the turbine and the escape of the flue gases 29 are directed downwards and the fuel supply pipe 30 runs along one of the support arms 24 of the device.

The gearbox 16 operates as a gearbox and may include an inverter system for rolling in reverse.

This embodiment has the advantage of a shorter fuel supply pipe 7, easier access to the micro-turbine for maintenance actions and, since this device is not essential, it is possible to fly an aircraft whose micro-turbines have been dismantled for maintenance reasons.

To counter vibrations, a device such as a connecting rod 20, shown in dashed lines in FIG. 2, linking the landing gear leg to the turbomachine is furthermore provided according to this embodiment.

Returning to FIG. 1, the invention provides means for reducing noise emissions during the operation of the micro-turbine, these means being produced according to the example in the form of an acoustically-treated expansion torus 21.

With such a system, the main engines being extinguished during the taxiing phase, the total consumption of oil for the same mission decreases. substantially and up to 5% of fuel can be saved on a mission to

500 nm for a standard airliner.

Similarly, global and local pollutant emissions are reduced, as is the noise level. Finally, taxiing with the aircraft engines stopped prevents the ingestion of foreign debris by the engines in this phase on the ground.

The device according to the invention allows autonomous movements of the aircraft on the ground, without the help of runway tractors, which saves time and reduces operating costs. Unlike an electric or hydraulic motor, the device according to the invention does not require major modifications of the architecture of the aircraft. Only a fuel line connecting it to one of the aircraft's tanks and a power supply of its low-power starter must be added by micro-turbine. Depending on the desired mechanical power and torque levels for driving, several configurations are possible: either a micro-turbine per wheel or a micro-turbine per train.

It is possible to arrange the turbine machine on the front wheel or to house the micro-turbine or turbines in the axles of the wheels of the main trains, which allows, in the latter case, because of the proximity of the tanks, to minimize the additional mass due to the addition of the fuel line.

Claims

R E V E N D I C A T IO N S

1 - Device for driving at least one wheel (13) of a landing gear of an aircraft, comprising at least one turbine machine (1), for which the turbine machine (1) is a turbomachine integrated in the landing gear of the aircraft and comprising a combustion chamber (3) in communication with an axial turbine stage (4) driving a compression stage (2). 2 - Drive device according to claim 1, characterized in that the turbomachine is a micro-turbine.

3 - Drive device according to claim 1 or 2, wherein the micro-turbine type turbomachine comprises a single-flow turbojet.

4 - Drive device according to one of claims 1 to 3, wherein the turbomachine comprises a compression stage (2) in the form of a centrifugal compressor.

5 - Drive device according to one of the preceding claims, wherein the turbomachine comprises a free turbine stage (5) driving at least one wheel (13) of the aircraft through mechanical transmission means (6).

6 - Drive device according to claim 5, wherein the mechanical transmission means (6) comprise a clutch system interposed between the turbomachine and said at least one wheel.

7 - Drive device according to claims 5 and 6, wherein the mechanical transmission means (6) comprise a fixed or variable reducer.

8 - Drive device according to one of claims 5 to 7, wherein the mechanical transmission means (6) comprise a device for reversing the direction of rotation of the wheels to allow the autonomous movement of the apparatus in reverse .

9 - Drive device according to one of claims 1 to 8, characterized in that it comprises a feed system comprising a fuel supply line (7) connecting the tanks of the aircraft to the turbomachine and a fuel management system (9) connected to a control (11) in the cockpit driving a valve (8) for closing the fuel supply located on the fuel supply line.