WO2024251750A1 - Method for securing a parking function in an aircraft braking system - Google Patents
Method for securing a parking function in an aircraft braking system Download PDFInfo
- Publication number
- WO2024251750A1 WO2024251750A1 PCT/EP2024/065362 EP2024065362W WO2024251750A1 WO 2024251750 A1 WO2024251750 A1 WO 2024251750A1 EP 2024065362 W EP2024065362 W EP 2024065362W WO 2024251750 A1 WO2024251750 A1 WO 2024251750A1
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- WIPO (PCT)
- Prior art keywords
- solenoid valve
- aircraft
- parking
- brakes
- protection
- Prior art date
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/17—Using electrical or electronic regulation means to control braking
- B60T8/1701—Braking or traction control means specially adapted for particular types of vehicles
- B60T8/1703—Braking or traction control means specially adapted for particular types of vehicles for aircrafts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C25/00—Alighting gear
- B64C25/32—Alighting gear characterised by elements which contact the ground or similar surface
- B64C25/42—Arrangement or adaptation of brakes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/40—Failsafe aspects of brake control systems
- B60T2270/402—Back-up
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/40—Failsafe aspects of brake control systems
- B60T2270/406—Test-mode; Self-diagnosis
Definitions
- the invention relates to hydraulic braking circuits for aircraft comprising a parking function.
- Figure 1 illustrates a hydraulic braking circuit 1 for an aircraft known per se operating from a hydraulic generation 100 comprising a pressure source 101 and a return reservoir 102.
- the hydraulic braking system comprises:
- a secondary pressure source in the form here of an accumulator 2 supplied by the pressure source 101 and associated with a non-return valve 4 and a pressure limiting valve 5;
- solenoid valve 6 for selectively supplying one or more servovalves 7a, 7b, each applying an adjusted pressure to pistons of hydraulic brake crowns 12a, 12b equipping wheels 11a, 11b carried by landing gears of the aircraft to brake said wheels;
- At least one brake control unit 14 which controls the solenoid valve 6 and controls the servovalves 7a, 7b independently of each other by means of electrical signals corresponding to the desired pressure in each brake in response to a brake instruction. braking generated by the pilot or other aircraft systems;
- Such a braking system includes a parking function to activate the brakes to immobilize the aircraft in parking when it is stationary. This function is achieved by:
- a parking brake control unit 16 controlling the parking solenoid valve 13 according to the driver's request to apply parking pressure in the brakes 12a, 12b.
- the involuntary application of pressure above a certain threshold in the brakes causes the wheels concerned to lock, resulting in the tire bursting.
- the loss of at least one tire on one of the braked wheels has the effect of increasing the braking distance, with the tire bursting on all the braked wheels risking taking the aircraft beyond the runway threshold.
- the aircraft system commonly includes a three-way/two-position safety solenoid valve 6 located upstream of the servovalves 7a, 7b in order to connect the hydraulic supply port of these servovalves either with the pressure source 101 and the accumulator 2 when the safety solenoid valve 6 is commanded, or with the return 102 when the safety solenoid valve 6 is at rest.
- the brake control unit 14 does not apply any electrical command to the safety solenoid valve 6 and the servovalves 7a, 7b as long as the pilot or another system does not request to brake the aircraft.
- This type of architecture avoids inadvertently pressurizing the brakes via the servovalves 7a, 7b, which constitutes a catastrophic event.
- the park solenoid valve 13 is always hydraulically supplied at its supply port as long as the external hydraulic generation 100 is in service or the hydraulic accumulator 2 is filled, which is always the case for the aircraft during taxiing, takeoff, landing operations, but also during the flight phases. Consequently, the parking solenoid valve 13 must be designed so that it cannot experience any simple failure that could lead to unwanted pressurization of the brakes via the shuttle valves 8a, 8b. Satisfying this constraint involves complex design and integration choices, such as the use of an electric motor type actuator, which has the disadvantage of being expensive, bulky and heavy. In addition, this solution requires a device for controlling the electric motor(s) of the solenoid valve 13 that can be integrated into the parking brake control unit 16.
- the invention aims to propose a simple method for securing the park function, preventing any simple breakdown from leading to a catastrophic event.
- a method for securing a parking function of a hydraulic braking circuit supplying brakes of braked wheels carried by landing gear of an aircraft, the hydraulic circuit comprising a parking solenoid valve having a service port connected to the brakes and a supply port connected in the rest position to a hydraulic return of the aircraft, the parking solenoid valve being controllable to connect said supply port with a pressure source so as to selectively transmit to the brakes of the aircraft a pressure sufficient to cause the actuation of the brakes ensuring the immobilization of the aircraft, the method of the invention comprising the steps of: arranging in series with the parking solenoid valve a protection solenoid valve allowing at rest the supply of pressure to the brakes via the parking solenoid valve, and which is controllable to prohibit the supply of pressure to the brakes via the parking solenoid valve; control the protection solenoid valve at least in a situation where a failure of the parking solenoid valve may induce unwanted braking.
- the presence of the protection solenoid valve makes it possible to accept cases of simple failure of the parking solenoid valve while ensuring that these simple failures cannot lead to catastrophic situations, a possible simple failure of the parking solenoid valve being neutralized by the actuation of the protection solenoid valve which prevents an unwanted application of pressure in the brakes.
- the control of the protection solenoid valve intervenes in a situation of failure of the solenoid valve, either curatively when the unwanted braking has already occurred, which makes the aircraft controllable on the ground again, or preventively to prevent any unwanted braking likely to occur.
- This arrangement makes it possible to considerably simplify the design of the park solenoid valve, which can then be satisfied with a simple solenoid actuation rather than based on electric motors.
- This arrangement also makes it possible to simplify the installation of the park solenoid valve within the aircraft, but also to reduce its mass and its size, while improving the safety of the aircraft.
- the protection solenoid valve is arranged upstream of the park solenoid valve, between the latter and a source of pressure.
- the protection solenoid valve is of the three-way/two-position type.
- pressure information from a pressure sensor located on a hydraulic line between the park solenoid valve and the protection solenoid valve is used.
- control of the protection solenoid valve is developed taking into account the following information:
- a switch is placed on an electrical line carrying the control of the protection solenoid valve, the switch being normally closed, and controllable to be open, thus preventing any possible control of the protection solenoid valve.
- the protection solenoid valve is of the two-way/two-position type. According to a particular embodiment of the invention, the protection solenoid valve is arranged downstream of the parking solenoid valve, between the latter and the brakes.
- FIG. 1 Figure 1, already commented on, is a diagram of an aircraft hydraulic braking circuit according to the prior art
- Figure 2 is a diagram of a hydraulic braking circuit according to a first embodiment of the invention.
- FIG. 3a Figure 3a is the beginning of a flowchart describing the test logic for verifying the proper functioning of the equipment providing parking braking;
- Figure 3b is the end of the flowchart started in Figure 3a;
- Figure 4 is an extract from a diagram of a hydraulic braking circuit according to a second embodiment of the invention.
- Figure 5 is a diagram of a hydraulic braking circuit according to a third embodiment of the invention.
- a protection solenoid valve 20 is arranged in series with the park solenoid valve 13, here upstream of the latter.
- the protection solenoid valve 20 is a three-way/two-position solenoid valve, the supply port of which is, in the rest position, connected to the pressure source 101 and to the accumulator 2, while the service port is connected to the supply port of the park solenoid valve 13.
- the protection solenoid valve 20 is thus interposed between the pressure source 101 (and the accumulator 2) and the park solenoid valve 13.
- the protection solenoid valve 20 In the rest position illustrated here, the protection solenoid valve 20 is normally conductive and connects its supply port with its service port so that the park solenoid valve 13 is supplied with pressure. When commanded, the protection solenoid valve 20 connects its service port to its return port connected to the return 102 of the hydraulic circuit so that the park solenoid valve 13 is no longer supplied with pressure.
- a pressure sensor 21 is placed on the hydraulic line connecting the protection solenoid valve 20 to the park solenoid valve 13, enabling the following monitoring to be carried out:
- the protection solenoid valve 20 is controlled, if the park solenoid valve 13 is not controlled, and if the pressure sensor 21 detects a pressure greater than a certain threshold, for example a threshold of 50 bars, then information is sent to the aircraft maintenance system indicating that the protection solenoid valve 20 is in a stuck open failure mode. • If the protection solenoid valve 20 is not controlled, if the pressure sensor 21 detects a pressure below a certain threshold, for example 50 bars, and if the pressure of the accumulator 2, measured by means of the pressure sensor 3, indicates a value greater than its pre-charge value, for example 100 bars, then information is sent to the aircraft maintenance system indicating that the protection solenoid valve 20 is in a blocked closed failure mode.
- a certain threshold for example a threshold of 50 bars
- the protection solenoid valve 20 is controlled according to the conditions in which the aircraft operates, and more particularly the conditions in which an untimely pressurization of one or more brakes would cause unfortunate consequences for the aircraft or the passengers. Conversely, the protection solenoid valve 20 may not be controlled in the conditions for which the actuation of the parking brake by the pilot is permitted, for example when the aircraft is stationary, or without major consequences, for example during taxiing or any other phase in which it is deemed that the protection provided by the protection solenoid valve is not essential.
- the protection solenoid valve 20 In order to minimize the electrical energy consumption for controlling the protection solenoid valve 20, it is preferably controlled only in the phases where the pressurization of one or more brakes by the parking solenoid valve 13 would be critical for the aircraft or its passengers. Another strategy, but less optimal in terms of electrical energy consumption, consists in controlling the protection solenoid valve 20 only in the phases where the parking solenoid valve 13 requires to be ordered.
- the control order of the protection solenoid valve 20 is preferably generated by the braking control unit 14, and is determined from measurement information and observations of states coming from sensors installed on the braking system but also from information coming from other systems, such as the landing gear extension/retraction system 22, or the aircraft navigation system providing in particular the speed and altitude of the aircraft.
- the information taken into account for the development of the control order of the protection solenoid valve 20 is as follows:
- the logic instructions implemented within the braking control unit 14 are as follows:
- the protection solenoid valve 20 is not controlled (this condition is encountered when the aircraft is in flight with the landing gears retracted);
- the protection solenoid valve 20 is controlled (this condition is met when the aircraft is approaching to land or just after takeoff); If at least one landing gear is depressed and if the rotation speed of at least one braked wheel is greater than or equal to a threshold speed Vc then: the protection solenoid valve 20 is controlled (this condition is met when the aircraft is in the taxiing phase at a speed greater than or equal to Vc);
- the protection solenoid valve 20 is not controlled (this condition is encountered when the aircraft is stationary or in the taxiing phase at a speed lower than a threshold speed Vc).
- the threshold speed Vc is defined so that in the event of untimely braking the consequences for the aircraft are not critical, for example a speed Vc of 20 Kts, which makes it possible to reduce the control time of the protection solenoid valve 20 and thus limit the electrical consumption.
- the logic instructions implemented within the braking control unit 14 are as follows:
- the protection valve is commanded (condition when the aircraft is on approach to land or just after take-off);
- the protection valve is controlled (condition when the aircraft is in the taxiing phase at a speed greater than or equal to Vc);
- the protection valve is not controlled (condition when the aircraft is stationary or taxiing at a speed lower than Vc);
- the protection valve is controlled (condition when the aircraft is in the taxiing phase at a speed greater than or equal to Vc);
- the protection valve is not controlled (condition when the aircraft is stationary or taxiing at a speed lower than Vc).
- the protection solenoid valve 20 is controlled when the aircraft is stationary in the event that the parking solenoid valve 13 is blocked in the open position in order to be able to depressurize the brakes and thus allow the aircraft to be towed.
- an electrical switch 23 is arranged on an electrical line carrying the control of the protection solenoid valve 20, the electrical switch 23 being controllable by the parking brake control unit 16.
- the switch 23 is normally closed. However, the driver can force the opening of this switch by controlling it via the parking brake control unit 16, which prevents any possible control of the protection solenoid valve 20, so that the parking solenoid valve 13 is thus supplied with pressure. This situation can occur in the event of a failure of the braking circuit, leading the driver to attempt emergency braking using the parking brake.
- the opening of the switch 23 ensures that, despite a command generated by the brake control unit 14, the protection solenoid valve 20 is in its rest position ensuring the pressure supply of the parking solenoid valve 13.
- the electrical switch 23 can be operated directly by maintenance personnel, for example to force the activation of the parking brake in case of failure of the parking brake control unit 16 or for ground tests of the protection solenoid valve 20.
- Monitoring the proper operation of the electrical switch 23 and the protection solenoid valve 20 is carried out during a functional test. This test can be carried out by observing the variation in the pressure level measured by the pressure sensor 21. Before controlling the park solenoid valve 13, the pressure must be below a given threshold, for example 50 bars. It is ensured that controlling the park solenoid valve 13 causes the switch 23 to open, which returns the protection solenoid valve 20 to the rest position if it was not already there, causing an increase in the pressure measured by the pressure sensor 21 above a certain threshold, for example 100 bars. In the event that this pressure level is not reached, information is sent to the maintenance system indicating that the switch 23 is stuck in the closed position.
- a given threshold for example 50 bars.
- the flowchart of Figures 3a and 3b describes an example of a functional test sequence for detecting the failure of one of the components performing the protection function of the parking solenoid valve 13.
- the parking solenoid valves 13 and the protection solenoid valve 20 are not controlled (they can however be faulty by being stuck open or closed).
- the three-way/two-position protection solenoid valve 20 is replaced by a two-way/two-position protection solenoid valve 20'.
- This alternative solution offers the advantage of removing a leak path between the supply port and the return port, which makes it possible to optimize the sizing of the hydraulic accumulator.
- a pressure sensor 21' is preferably arranged between the two solenoid valves to help detect failures.
- the protection solenoid valve 20'' is positioned still in series with the park solenoid valve 13, but this time downstream of the latter.
- a pressure sensor 21'' is preferably arranged between the two solenoid valves to help detect faults.
- the pressure sensors 10a, 10b used for the anti-skid function are used directly to provide a pressure measurement making it possible to monitor the proper operation of the park solenoid valves 13 and protection 20, thus avoiding the installation of the pressure sensor 21.
- the protection provided by the protective solenoid valve 20, in combination or not with the controlled switch 23, therefore makes it possible to prevent a simple failure of the parking solenoid valve 13 from leading to an unwanted braking situation or any other catastrophic situation. It is therefore possible to be satisfied with a single-actuated parking solenoid valve.
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- Engineering & Computer Science (AREA)
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- Aviation & Aerospace Engineering (AREA)
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- Valves And Accessory Devices For Braking Systems (AREA)
- Regulating Braking Force (AREA)
Abstract
Description
PROCEDE DE SECURISATION D' UNE FONCTION DE PARC DANS UN SYSTEME DE FREINAGE D' AERONEF METHOD FOR SECURING A PARKING FUNCTION IN AN AIRCRAFT BRAKING SYSTEM
L' invention concerne les circuit s de freinage hydraulique pour aéronef comportant une fonction de parc . The invention relates to hydraulic braking circuits for aircraft comprising a parking function.
ARRIERE PLAN DE LINVENTION BACKGROUND OF THE INVENTION
La figure 1 illustre un circuit de freinage hydraulique 1 pour aéronef connu en soi opérant à partir d' une génération hydraulique 100 comportant une source de pression 101 et un réservoir de retour 102 . Le système de freinage hydraulique comprend : Figure 1 illustrates a hydraulic braking circuit 1 for an aircraft known per se operating from a hydraulic generation 100 comprising a pressure source 101 and a return reservoir 102. The hydraulic braking system comprises:
- une source de pression secondaire sous la forme ici d' un accumulateur 2 alimenté par la source de pression 101 et associé à un clapet anti-retour 4 et à une valve de limitation de pression 5 ; - a secondary pressure source in the form here of an accumulator 2 supplied by the pressure source 101 and associated with a non-return valve 4 and a pressure limiting valve 5;
- un capteur de pression 3 permettant de surveiller le niveau de pression dans l ' accumulateur 2 ; - a pressure sensor 3 for monitoring the pressure level in the accumulator 2;
- une électrovanne 6 permettant d' alimenter sélectivement une ou des servovalves 7a, 7b appliquant chacune une pression ajustée sur des pistons de couronnes hydrauliques de freins 12a, 12b équipant des roues lia, 11b portées par des atterrisseurs de l ' aéronef pour freiner lesdites roues ; - a solenoid valve 6 for selectively supplying one or more servovalves 7a, 7b, each applying an adjusted pressure to pistons of hydraulic brake crowns 12a, 12b equipping wheels 11a, 11b carried by landing gears of the aircraft to brake said wheels;
- des capteurs de pression 10a, 10b disposés chacun sur une ligne d' alimentation des freins 12a, 12b pour mesurer la pression dans les freins ; - pressure sensors 10a, 10b each arranged on a brake supply line 12a, 12b to measure the pressure in the brakes;
- des fusibles hydrauliques 9a, 9b disposés chacun sur une ligne d' alimentation des freins 12a, 12b permettant d' éviter la perte totale de l ' alimentation hydraulique en cas de rupture des lignes d' alimentation en aval des fusibles ; - hydraulic fuses 9a, 9b each arranged on a brake supply line 12a, 12b making it possible to avoid total loss of hydraulic supply in the event of rupture of the supply lines downstream of the fuses;
- au moins une unité de commande de freinage 14 qui commande l ' électrovanne 6 et pilote les servovalves 7a, 7b indépendamment l ' une de l' autre au moyen de signaux électriques correspondant à la pression désirée dans chaque frein en réponse à une consigne de freinage générée par le pilote ou d' autres systèmes de l ' aéronef ; - at least one brake control unit 14 which controls the solenoid valve 6 and controls the servovalves 7a, 7b independently of each other by means of electrical signals corresponding to the desired pressure in each brake in response to a brake instruction. braking generated by the pilot or other aircraft systems;
- des tachymètres 17a, 17b permettant de mesurer la vitesse de rotation de chaque roue freinée nécessaire à la fonction anti-patinage assurée par l ' unité de commande de freinage 14 ; - tachometers 17a, 17b for measuring the rotation speed of each braked wheel required for the anti-skid function provided by the brake control unit 14;
- des clapets anti-retour 15 pour empêcher une pressurisation des freins dans le cas d' une élévation de la pression sur la ligne retour vers le réservoir de la génération hydraulique . - non-return valves 15 to prevent pressurization of the brakes in the event of an increase in pressure on the return line to the hydraulic generation reservoir.
Un tel système de freinage comporte une fonction de parc permettant d' activer les freins pour immobiliser l ' aéronef au parking lorsqu' il est l ' arrêt . Cette fonction est réalisée grâce à : Such a braking system includes a parking function to activate the brakes to immobilize the aircraft in parking when it is stationary. This function is achieved by:
- des clapets navette 8a, 8b placés sur les lignes d' alimentation des freins pour permettre l ' imposition d' une pression de parc dans les freins 12a, 12b via le port de service d' une électrovanne de parc 13 ayant un port d' alimentation connecté en position de repos au retour 102 de l ' alimentation, et étant commandable pour connecter le port d' alimentation à la source de pression 101 et/ou à l ' accumulateur 2 , de sorte à transmettre la pression d' alimentation directement aux freins via les clapets navette 8 ;- shuttle valves 8a, 8b placed on the brake supply lines to allow the imposition of a parking pressure in the brakes 12a, 12b via the service port of a parking solenoid valve 13 having a supply port connected in the rest position to the supply return 102, and being controllable to connect the supply port to the pressure source 101 and/or to the accumulator 2, so as to transmit the supply pressure directly to the brakes via the shuttle valves 8;
- une unité de commande de frein de parc 16 pilotant l ' électrovanne de parc 13 selon la demande du pilote pour appliquer une pression de parc dans les freins 12a, 12b . - a parking brake control unit 16 controlling the parking solenoid valve 13 according to the driver's request to apply parking pressure in the brakes 12a, 12b.
La réglementation aéronautique impose que les systèmes de freinage d' aéronef soient conçus de sorte qu' aucune panne simple ne puisse entrainer un événement catastrophique . Ci-dessous sont donnés deux exemples de scénarios pour lesquels un événement catastrophique pourrait se produire : 1/ Pendant la phase de décollage, l'application non volontaire d'une pression supérieure à un certain seuil dans un certain nombre de freins entraine une augmentation de la distance de décollage, voire empêche l'aéronef d'atteindre la vitesse minimale pour décoller avec pour conséquence le risque de dépasser la fin de piste. Aviation regulations require that aircraft braking systems be designed so that no single failure can result in a catastrophic event. Below are two examples of scenarios in which a catastrophic event could occur: 1/ During the take-off phase, the involuntary application of pressure above a certain threshold in a certain number of brakes leads to an increase in the take-off distance, or even prevents the aircraft from reaching the minimum speed for take-off, with the resulting risk of going beyond the end of the runway.
2/ Pendant la phase d'atterrissage, l'application non volontaire d'une pression supérieure à un certain seuil dans des freins entraine le blocage des roues concernées avec pour effet l'éclatement du pneumatique. La perte d'au moins un pneumatique sur une des roues freinées a pour conséquence d'augmenter la distance de freinage, l'éclatement des pneumatiques de l'ensemble des roues freinées risquant d'amener l'aéronef au-delà du seuil de piste. 2/ During the landing phase, the involuntary application of pressure above a certain threshold in the brakes causes the wheels concerned to lock, resulting in the tire bursting. The loss of at least one tire on one of the braked wheels has the effect of increasing the braking distance, with the tire bursting on all the braked wheels risking taking the aircraft beyond the runway threshold.
Pour éviter de tels scénarios, le système de l'aéronef comprend communément une électrovanne de sécurité 6 trois voies / deux positions située en amont des servovalves 7a, 7b afin de connecter le port d'alimentation hydraulique de ces servovalves soit avec la source de pression 101 et l'accumulateur 2 quand l'électrovanne de sécurité 6 est commandée, soit avec le retour 102 quand l'électrovanne de sécurité 6 est au repos. Pendant les phases critiques au sol, tel qu'au décollage, l'unité de commande de freinage 14 n'applique aucune commande électrique à l'électrovanne de sécurité 6 et aux servovalves 7a, 7b tant que le pilote ou un autre système ne demande pas à freiner l'aéronef. Ce type d'architecture évite de pressuriser intempestivement les freins via les servovalves 7a, 7b, ce qui constitue un événement catastrophique. To avoid such scenarios, the aircraft system commonly includes a three-way/two-position safety solenoid valve 6 located upstream of the servovalves 7a, 7b in order to connect the hydraulic supply port of these servovalves either with the pressure source 101 and the accumulator 2 when the safety solenoid valve 6 is commanded, or with the return 102 when the safety solenoid valve 6 is at rest. During critical phases on the ground, such as takeoff, the brake control unit 14 does not apply any electrical command to the safety solenoid valve 6 and the servovalves 7a, 7b as long as the pilot or another system does not request to brake the aircraft. This type of architecture avoids inadvertently pressurizing the brakes via the servovalves 7a, 7b, which constitutes a catastrophic event.
On remarque cependant que l'électrovanne de parc 13 est toujours alimentée hydrauliquement à son port d'alimentation tant que la génération hydraulique externe 100 est en service ou l'accumulateur hydraulique 2 est rempli, ce qui est toujours le cas de l'aéronef lors des opérations de roulage au sol, de décollage, d'atterrissage mais aussi lors des phases de vol. Par conséquent, l'électrovanne de parc 13 doit être conçue de sorte qu'elle ne puisse connaître aucune panne simple pouvant entrainer une pressurisation non désirée des freins via les clapets navette 8a, 8b. Satisfaire cette contrainte implique des choix de conception et d'intégration complexes, tel que l'usage d'un actionneur de type moteur électrique ce qui présente l'inconvénient d'être coûteux, encombrant et lourd. De plus cette solution impose un dispositif de contrôle du ou des moteurs électriques de l'électrovanne 13 qui peut être intégré au niveau de l'unité de commande du frein de parc 16. It should be noted, however, that the park solenoid valve 13 is always hydraulically supplied at its supply port as long as the external hydraulic generation 100 is in service or the hydraulic accumulator 2 is filled, which is always the case for the aircraft during taxiing, takeoff, landing operations, but also during the flight phases. Consequently, the parking solenoid valve 13 must be designed so that it cannot experience any simple failure that could lead to unwanted pressurization of the brakes via the shuttle valves 8a, 8b. Satisfying this constraint involves complex design and integration choices, such as the use of an electric motor type actuator, which has the disadvantage of being expensive, bulky and heavy. In addition, this solution requires a device for controlling the electric motor(s) of the solenoid valve 13 that can be integrated into the parking brake control unit 16.
OBJET DE L'INVENTION SUBJECT OF THE INVENTION
L'invention vise à proposer un procédé de sécurisation simple de la fonction de parc évitant que toute panne simple conduise à un évènement catastrophique. The invention aims to propose a simple method for securing the park function, preventing any simple breakdown from leading to a catastrophic event.
RESUME DE L'INVENTION SUMMARY OF THE INVENTION
En vue de la réalisation de ce but, on propose un procédé de sécurisation d'une fonction de parc d'un circuit hydraulique de freinage alimentant des freins de roues freinées portées par des atterrisseurs d'un aéronef, le circuit hydraulique comportant une électrovanne de parc ayant un port de service relié aux freins et un port d'alimentation relié en position de repos à un retour hydraulique de l'aéronef, l'électrovanne de parc étant commandable pour mettre en relation ledit port d'alimentation avec une source de pression de sorte à transmettre sélectivement aux freins de l'aéronef une pression suffisante pour provoquer 1 ' act ionnement des freins assurant l'immobilisation de l'aéronef, le procédé de l'invention comportant les étapes de : disposer en série avec l'électrovanne de parc une électrovanne de protection permettant au repos l'alimentation en pression des freins via l'électrovanne de parc, et qui est commandable pour interdire l'alimentation en pression des freins via l'électrovanne de parc ; commander l'électrovanne de protection au moins dans une situation où une défaillance de l'électrovanne de parc peut induire un freinage non désiré. In order to achieve this goal, a method is proposed for securing a parking function of a hydraulic braking circuit supplying brakes of braked wheels carried by landing gear of an aircraft, the hydraulic circuit comprising a parking solenoid valve having a service port connected to the brakes and a supply port connected in the rest position to a hydraulic return of the aircraft, the parking solenoid valve being controllable to connect said supply port with a pressure source so as to selectively transmit to the brakes of the aircraft a pressure sufficient to cause the actuation of the brakes ensuring the immobilization of the aircraft, the method of the invention comprising the steps of: arranging in series with the parking solenoid valve a protection solenoid valve allowing at rest the supply of pressure to the brakes via the parking solenoid valve, and which is controllable to prohibit the supply of pressure to the brakes via the parking solenoid valve; control the protection solenoid valve at least in a situation where a failure of the parking solenoid valve may induce unwanted braking.
La présence de l'électrovanne de protection permet d'admettre des cas de panne simple de l'électrovanne de parc tout en faisant en sorte que ces pannes simples ne puissent conduire à des situations catastrophiques, une éventuelle panne simple de l'électrovanne de parc étant neutralisée par l' actionnement de l'électrovanne de protection qui empêche une application non désirée de pression dans les freins. The presence of the protection solenoid valve makes it possible to accept cases of simple failure of the parking solenoid valve while ensuring that these simple failures cannot lead to catastrophic situations, a possible simple failure of the parking solenoid valve being neutralized by the actuation of the protection solenoid valve which prevents an unwanted application of pressure in the brakes.
La commande de l'électrovanne de protection intervient dans une situation de défaillance de l'électrovanne, soit de façon curative alors que le freinage non désiré soit déjà survenu, ce qui rend de nouveau l'aéronef contrôlable au sol, soit de façon préventive pour empêcher tout freinage non désiré susceptible de survenir. The control of the protection solenoid valve intervenes in a situation of failure of the solenoid valve, either curatively when the unwanted braking has already occurred, which makes the aircraft controllable on the ground again, or preventively to prevent any unwanted braking likely to occur.
Cette disposition permet de simplifier considérablement la conception de l'électrovanne de parc, pouvant alors se contenter d'un actionnement à simple solénoïde plutôt qu'à base de moteurs électriques. Cette disposition permet également de simplifier l'installation de l'électrovanne de parc au sein de l'aéronef, mais aussi de réduire sa masse et son encombrement, tout en améliorant la sûreté de 1' aéronef . This arrangement makes it possible to considerably simplify the design of the park solenoid valve, which can then be satisfied with a simple solenoid actuation rather than based on electric motors. This arrangement also makes it possible to simplify the installation of the park solenoid valve within the aircraft, but also to reduce its mass and its size, while improving the safety of the aircraft.
Selon une mise en œuvre particulière du procédé de l'invention, on dispose l'électrovanne de protection en amont de l'électrovanne de parc, entre celle-ci et une source de pression. According to a particular implementation of the method of the invention, the protection solenoid valve is arranged upstream of the park solenoid valve, between the latter and a source of pressure.
De préférence, l'électrovanne de protection est du type trois voies / deux positions. Preferably, the protection solenoid valve is of the three-way/two-position type.
Selon une autre mise en œuvre particulière du procédé de l'invention, on réalise des tests fonctionnels permettant de détecter une éventuelle défaillance en commandant et décommandant successivement l'électrovanne de parc et l'électrovanne de protection. According to another particular implementation of the method of the invention, functional tests are carried out to detect a possible failure by successively controlling and cancelling the park solenoid valve and the protection solenoid valve.
De préférence alors, on utilise une information de pression provenant d'un capteur de pression disposé sur une ligne hydraulique entre l'électrovanne de parc et l'électrovanne de protection. Preferably then, pressure information from a pressure sensor located on a hydraulic line between the park solenoid valve and the protection solenoid valve is used.
De préférence également, les tests fonctionnels sont exécutés à chaque mise en route de l'aéronef. Also preferably, functional tests are performed each time the aircraft is started up.
Selon un mode particulier de mise en œuvre du procédé de l'invention, on élabore la commande de l'électrovanne de protection en tenant compte des informations suivantes: According to a particular mode of implementation of the method of the invention, the control of the protection solenoid valve is developed taking into account the following information:
• une vitesse de rotation de chaque roue freinée ; • a rotation speed of each braked wheel;
• une information d'enfoncement d' atterrisseurs de l'aéronef portant les roues freinées ; • information on the sinking of the aircraft's landing gear with braked wheels;
• une information de verrouillage en position déployée de chacun des atterrisseurs équipés de roues freinées.• information on locking in the deployed position of each of the landing gears equipped with braked wheels.
Selon un mode particulier de mise en œuvre du procédé de l'invention, on dispose un interrupteur sur une ligne électrique transportant la commande de l'électrovanne de protection, l'interrupteur étant normalement fermé, et commandable pour être ouvert interdisant ainsi toute commande éventuelle de l'électrovanne de protection. According to a particular embodiment of the method of the invention, a switch is placed on an electrical line carrying the control of the protection solenoid valve, the switch being normally closed, and controllable to be open, thus preventing any possible control of the protection solenoid valve.
Selon un mode particulier de mise en œuvre du procédé de l'invention, l'électrovanne de protection est du type deux voies / deux positions. Selon un mode particulier de mise en œuvre de l'invention, on dispose l'électrovanne de protection en aval de l'électrovanne de parc, entre celle-ci et les freins. According to a particular embodiment of the method of the invention, the protection solenoid valve is of the two-way/two-position type. According to a particular embodiment of the invention, the protection solenoid valve is arranged downstream of the parking solenoid valve, between the latter and the brakes.
BREVE DESCRIPTION DES DESSINSBRIEF DESCRIPTION OF THE DRAWINGS
L'invention sera mieux comprise à la lumière de la description qui suit de modes de mise en œuvre de l'invention, en référence aux figures des dessins annexés parmi lesquelles : The invention will be better understood in light of the following description of embodiments of the invention, with reference to the figures of the appended drawings, among which:
[Fig. 1] la figure 1, déjà commentée, est un schéma d'un circuit de freinage hydraulique d'aéronef selon l'art antérieur ; [Fig. 1] Figure 1, already commented on, is a diagram of an aircraft hydraulic braking circuit according to the prior art;
[Fig. 2] la figure 2 est un schéma d'un circuit de freinage hydraulique selon un premier mode de mise en œuvre de l'invention ; [Fig. 2] Figure 2 is a diagram of a hydraulic braking circuit according to a first embodiment of the invention;
[Fig. 3a] la figure 3a est le début d'un logigramme décrivant la logique de test permettant de vérifier le bon fonctionnement des équipements assurant le freinage de parc ; [Fig. 3b] la figure 3b est la fin du logigramme commencé de la figure 3a ; [Fig. 3a] Figure 3a is the beginning of a flowchart describing the test logic for verifying the proper functioning of the equipment providing parking braking; [Fig. 3b] Figure 3b is the end of the flowchart started in Figure 3a;
[Fig. 4] la figure 4 est un extrait d'un schéma d'un circuit de freinage hydraulique selon un deuxième mode de mise en œuvre de l'invention ; [Fig. 4] Figure 4 is an extract from a diagram of a hydraulic braking circuit according to a second embodiment of the invention;
[Fig. 5] la figure 5 est un schéma d'un circuit de freinage hydraulique selon un troisième mode de mise en œuvre de 1' invention . [Fig. 5] Figure 5 is a diagram of a hydraulic braking circuit according to a third embodiment of the invention.
DESCRIPTION DETAILLEE DE LINVENTION DETAILED DESCRIPTION OF THE INVENTION
Un premier mode particulier de mise en œuvre est maintenant détaillé en référence à la figure 2. Sur cette figure, les éléments communs avec ceux de la figure 1 portent les mêmes références numériques et ne seront pas ici redétaillés. Selon l'invention, on dispose une électrovanne de protection 20 en série avec l'électrovanne de parc 13, ici en amont de cette dernière. Dans le mode de mise en œuvre illustré, l'électrovanne de protection 20 est une électrovanne trois voies / deux positions, dont le port d'alimentation est, dans la position de repos, connecté à la source de pression 101 et à l'accumulateur 2, tandis que le port de service est connecté au port d'alimentation de l'électrovanne de parc 13. L'électrovanne de protection 20 est ainsi interposée entre la source de pression 101 (et l'accumulateur 2) et l'électrovanne de parc 13. En position de repos illustrée ici, l'électrovanne de protection 20 est normalement passante et connecte son port d'alimentation avec son port de service de sorte que l'électrovanne de parc 13 est alimentée en pression. Lorsqu'elle est commandée, l'électrovanne de protection 20 connecte son port de service à son port de retour connecté au retour 102 du circuit hydraulique de sorte que l'électrovanne de parc 13 ne soit plus alimentée en pression. A first particular mode of implementation is now detailed with reference to Figure 2. In this figure, the elements common to those of Figure 1 bear the same numerical references and will not be detailed again here. According to the invention, a protection solenoid valve 20 is arranged in series with the park solenoid valve 13, here upstream of the latter. In the illustrated embodiment, the protection solenoid valve 20 is a three-way/two-position solenoid valve, the supply port of which is, in the rest position, connected to the pressure source 101 and to the accumulator 2, while the service port is connected to the supply port of the park solenoid valve 13. The protection solenoid valve 20 is thus interposed between the pressure source 101 (and the accumulator 2) and the park solenoid valve 13. In the rest position illustrated here, the protection solenoid valve 20 is normally conductive and connects its supply port with its service port so that the park solenoid valve 13 is supplied with pressure. When commanded, the protection solenoid valve 20 connects its service port to its return port connected to the return 102 of the hydraulic circuit so that the park solenoid valve 13 is no longer supplied with pressure.
Pour surveiller le fonctionnement de l'ensemble, on dispose un capteur de pression 21 sur la ligne hydraulique reliant l'électrovanne de protection 20 à l'électrovanne de parc 13 permettant d'effectuer les surveillances suivantes : To monitor the operation of the assembly, a pressure sensor 21 is placed on the hydraulic line connecting the protection solenoid valve 20 to the park solenoid valve 13, enabling the following monitoring to be carried out:
• Si l'électrovanne de protection 20 est commandée, si l'électrovanne de parc 13 n'est pas commandée, et si le capteur de pression 21 détecte une pression supérieure à un certain seuil, par exemple un seuil de 50 bars, alors une information est émise à destination du système de maintenance de l'aéronef indiquant que l'électrovanne de protection 20 est dans un mode de défaillance bloquée ouverte. • Si l'électrovanne de protection 20 n'est pas commandée, si le capteur de pression 21 détecte une pression inférieure à un certain seuil, par exemple 50 bars, et si la pression de l'accumulateur 2, mesurée au moyen du capteur de pression 3, indique une valeur supérieure à sa valeur de pré-charge, par exemple 100 bars, alors une information est émise à destination du système de maintenance de l'aéronef indiquant que l'électrovanne de protection 20 est dans un mode de défaillance bloquée fermée. • If the protection solenoid valve 20 is controlled, if the park solenoid valve 13 is not controlled, and if the pressure sensor 21 detects a pressure greater than a certain threshold, for example a threshold of 50 bars, then information is sent to the aircraft maintenance system indicating that the protection solenoid valve 20 is in a stuck open failure mode. • If the protection solenoid valve 20 is not controlled, if the pressure sensor 21 detects a pressure below a certain threshold, for example 50 bars, and if the pressure of the accumulator 2, measured by means of the pressure sensor 3, indicates a value greater than its pre-charge value, for example 100 bars, then information is sent to the aircraft maintenance system indicating that the protection solenoid valve 20 is in a blocked closed failure mode.
L'électrovanne de protection 20 est commandée en fonction des conditions dans lesquelles opère l'aéronef, et plus particulièrement les conditions dans lesquelles une pressurisation intempestive d'un ou plusieurs freins entraînerait des conséquences fâcheuses pour l'aéronef ou les passagers. A contrario, l'électrovanne de protection 20 peut ne pas être commandée dans les conditions pour lesquelles l' actionnement du frein de parc par le pilote est permis, par exemple lorsque l'aéronef est à l'arrêt, ou bien sans conséquence majeure, par exemple lors du taxiage ou tout autre phase dont on jugera que la protection apportée par l'électrovanne de protection n'est pas indispensable . The protection solenoid valve 20 is controlled according to the conditions in which the aircraft operates, and more particularly the conditions in which an untimely pressurization of one or more brakes would cause unfortunate consequences for the aircraft or the passengers. Conversely, the protection solenoid valve 20 may not be controlled in the conditions for which the actuation of the parking brake by the pilot is permitted, for example when the aircraft is stationary, or without major consequences, for example during taxiing or any other phase in which it is deemed that the protection provided by the protection solenoid valve is not essential.
Afin de minimiser la consommation d'énergie électrique pour la commande de l'électrovanne de protection 20, on commande de préférence celle-ci uniquement dans les phases où la pressurisation d'un ou plusieurs freins par l'électrovanne de parc 13 serait critique pour l'aéronef ou ses passagers. Une autre stratégie, mais moins optimale en termes de consommation d'énergie électrique, consiste à ne commander l'électrovanne de protection 20 uniquement dans les phases où l'électrovanne de parc 13 nécessite d'être commandée. In order to minimize the electrical energy consumption for controlling the protection solenoid valve 20, it is preferably controlled only in the phases where the pressurization of one or more brakes by the parking solenoid valve 13 would be critical for the aircraft or its passengers. Another strategy, but less optimal in terms of electrical energy consumption, consists in controlling the protection solenoid valve 20 only in the phases where the parking solenoid valve 13 requires to be ordered.
L'ordre de commande de l'électrovanne de protection 20 est de préférence généré par l'unité de commande de freinage 14, et est déterminé à partir d'informations de mesures et observations d'états provenant de capteurs installés sur le système de freinage mais aussi à partir d'informations provenant d'autres systèmes, tels que le système d'extension / rétraction des atterrisseurs 22, ou le système de navigation de l'aéronef fournissant notamment la vitesse et l'altitude de l'aéronef. The control order of the protection solenoid valve 20 is preferably generated by the braking control unit 14, and is determined from measurement information and observations of states coming from sensors installed on the braking system but also from information coming from other systems, such as the landing gear extension/retraction system 22, or the aircraft navigation system providing in particular the speed and altitude of the aircraft.
Selon un mode particulier de mise en œuvre de l'invention, les informations prises en compte pour l'élaboration de l'ordre de commande de l'électrovanne de protection 20 sont les suivantes : According to a particular embodiment of the invention, the information taken into account for the development of the control order of the protection solenoid valve 20 is as follows:
• la vitesse de rotation de chaque roue freinée au moyen de leurs tachymètres 17 respectifs ; • the rotation speed of each braked wheel by means of their respective tachometers 17;
• une information d'enfoncement de chaque atterrisseur de l'aéronef fournie par le système d'extension / rétraction 22 ; • information on the depression of each landing gear of the aircraft provided by the extension/retraction system 22;
• une information de verrouillage en position déployée de chacun des atterrisseurs équipé de roues freinées fournie par le système d'extension / rétraction 22. De préférence, les instructions logiques implémentées au sein de l'unité de commande de freinage 14 sont les suivantes : • information on locking in the deployed position of each of the landing gears equipped with braked wheels provided by the extension/retraction system 22. Preferably, the logic instructions implemented within the braking control unit 14 are as follows:
• Si tous les atterrisseurs ne sont pas déployés et verrouillés alors : l'électrovanne de protection 20 n'est pas commandée (cette condition est rencontrée lorsque l'aéronef est en vol avec les atterrisseurs rétractés) ; • If all the landing gears are not deployed and locked then: the protection solenoid valve 20 is not controlled (this condition is encountered when the aircraft is in flight with the landing gears retracted);
• Si au moins un atterrisseur est verrouillé en position déployée alors : • If at least one lander is locked in position deployed then:
Si tous les trains d'atterrissage ne sont pas enfoncés alors : l'électrovanne de protection 20 est commandée (cette condition est rencontrée lorsque l'aéronef est en approche pour atterrir ou alors juste après le décollage) ; Si au moins un atterrisseur est enfoncé et si la vitesse de rotation d'au moins une roue freinée est supérieure ou égale à une vitesse seuil Vc alors : l'électrovanne de protection 20 est commandée (cette condition est rencontrée lorsque l'aéronef est en phase de roulage à une vitesse supérieure ou égale à Vc) ; If all the landing gears are not depressed then: the protection solenoid valve 20 is controlled (this condition is met when the aircraft is approaching to land or just after takeoff); If at least one landing gear is depressed and if the rotation speed of at least one braked wheel is greater than or equal to a threshold speed Vc then: the protection solenoid valve 20 is controlled (this condition is met when the aircraft is in the taxiing phase at a speed greater than or equal to Vc);
Si au moins un atterrisseur est enfoncé et si la vitesse de rotation de toutes les roues freinées est inférieure à la vitesse seuil Vc alors : l'électrovanne de protection 20 n'est pas commandée (cette condition est rencontrée lorsque l'aéronef est à l'arrêt ou en phase de roulage à une vitesse inférieure à une vitesse de seuil Vc) . If at least one landing gear is depressed and if the rotation speed of all the braked wheels is lower than the threshold speed Vc then: the protection solenoid valve 20 is not controlled (this condition is encountered when the aircraft is stationary or in the taxiing phase at a speed lower than a threshold speed Vc).
La vitesse de seuil Vc est définie de telle sorte qu'en cas de freinage intempestif les conséquences au niveau de l'aéronef ne soient pas critiques, par exemple une vitesse Vc de 20 Kts, ce qui permet de réduire la durée de commande de l'électrovanne de protection 20 et ainsi limiter la consommation électrique. The threshold speed Vc is defined so that in the event of untimely braking the consequences for the aircraft are not critical, for example a speed Vc of 20 Kts, which makes it possible to reduce the control time of the protection solenoid valve 20 and thus limit the electrical consumption.
Selon un autre mode de mise en œuvre, les instructions logiques implémentées au sein de l'unité de commande de freinage 14 sont les suivantes: According to another embodiment, the logic instructions implemented within the braking control unit 14 are as follows:
• Si le levier de commande d'extension / rétraction est dans la position extension alors : • If the extension/retraction control lever is in the extension position then:
Si tous les trains d'atterrissage ne sont pas enfoncés alors : la valve de protection est commandée (condition lorsque l'aéronef est en approche pour atterrir ou alors juste après le décollage) ; If all landing gears are not down then: the protection valve is commanded (condition when the aircraft is on approach to land or just after take-off);
Si au moins un train d'atterrissage est enfoncé et si la vitesse de l'aéronef est supérieure ou égale à la vitesse Vc alors : la valve de protection est commandée (condition lorsque l'aéronef est en phase de roulage à une vitesse supérieure ou égale à Vc) ; If at least one landing gear is depressed and if the aircraft speed is greater than or equal to speed Vc then: the protection valve is controlled (condition when the aircraft is in the taxiing phase at a speed greater than or equal to Vc);
Si au moins un train d'atterrissage est enfoncé et si la vitesse de l'aéronef est inférieure à la vitesse Vc alors : la valve de protection n'est pas commandée (condition lorsque l'aéronef est à l'arrêt ou en phase de roulage à une vitesse inférieure Vc) ; If at least one landing gear is depressed and the aircraft speed is lower than speed Vc then: the protection valve is not controlled (condition when the aircraft is stationary or taxiing at a speed lower than Vc);
• Si le levier de commande d'extension / rétraction est dans la position rétractée alors : la valve de protection n'est pas commandée (condition lorsque l'aéronef est en vol avec les trains d'atterrissage rentrés) ; • If the extension/retraction control lever is in the retracted position then: the protection valve is not commanded (condition when the aircraft is in flight with the landing gear retracted);
• Si le levier de commande d'extension / rétraction est dans la position extension alors : • If the extension/retraction control lever is in the extension position then:
Si la vitesse de l'aéronef est supérieure ou égale à la vitesse Vc alors : la valve de protection est commandée (condition lorsque l'aéronef est en phase de roulage à une vitesse supérieure ou égale à Vc) ; If the aircraft speed is greater than or equal to speed Vc then: the protection valve is controlled (condition when the aircraft is in the taxiing phase at a speed greater than or equal to Vc);
Si la vitesse de l'aéronef est inférieure à la vitesse Vc alors : la valve de protection n'est pas commandée (condition lorsque l'aéronef est à l'arrêt ou en phase de roulage à une vitesse inférieure Vc) . If the aircraft speed is less than the speed Vc then: the protection valve is not controlled (condition when the aircraft is stationary or taxiing at a speed lower than Vc).
Selon une disposition particulière de l'invention, on commande l'électrovanne de protection 20 lorsque l'aéronef est à l'arrêt dans le cas où l'électrovanne de parc 13 serait bloquée en position ouverte afin de pouvoir dépressuriser les freins et permettre ainsi le tractage de l'aéronef . According to a particular arrangement of the invention, the protection solenoid valve 20 is controlled when the aircraft is stationary in the event that the parking solenoid valve 13 is blocked in the open position in order to be able to depressurize the brakes and thus allow the aircraft to be towed.
Selon une autre disposition particulière de l'invention, on dispose un interrupteur électrique 23 sur une ligne électrique transportant la commande de l'électrovanne de protection 20, l'interrupteur électrique 23 étant commandable par l'unité de commande de frein de parc 16. L'interrupteur 23 est normalement fermé. Cependant, le pilote peut forcer l'ouverture de cet interrupteur en le commandant via l'unité de commande de frein de parc 16, ce qui interdit toute commande éventuelle de l'électrovanne de protection 20, de sorte que l'électrovanne de parc 13 se retrouve ainsi alimentée en pression. Cette situation peut survenir en cas de défaillance du circuit de freinage, amenant le pilote à tenter un freinage de secours au moyen du frein de parc. L'ouverture de l'interrupteur 23 assure que, malgré une commande générée par l'unité de commande de freinage 14, l'électrovanne de protection 20 soit dans sa position de repos assurant l'alimentation en pression de l'électrovanne de parc 13. En variante, l'interrupteur électrique 23 est actionnable directement par le personnel de maintenance, pour par exemple forcer l'activation du freinage de parc en cas de défaillance de l'unité de commande de frein de parc 16 ou encore pour des tests au sol de l'électrovanne de protection 20. According to another particular arrangement of the invention, an electrical switch 23 is arranged on an electrical line carrying the control of the protection solenoid valve 20, the electrical switch 23 being controllable by the parking brake control unit 16. The switch 23 is normally closed. However, the driver can force the opening of this switch by controlling it via the parking brake control unit 16, which prevents any possible control of the protection solenoid valve 20, so that the parking solenoid valve 13 is thus supplied with pressure. This situation can occur in the event of a failure of the braking circuit, leading the driver to attempt emergency braking using the parking brake. The opening of the switch 23 ensures that, despite a command generated by the brake control unit 14, the protection solenoid valve 20 is in its rest position ensuring the pressure supply of the parking solenoid valve 13. Alternatively, the electrical switch 23 can be operated directly by maintenance personnel, for example to force the activation of the parking brake in case of failure of the parking brake control unit 16 or for ground tests of the protection solenoid valve 20.
La surveillance du bon fonctionnement de l'interrupteur électrique 23 et de l'électrovanne de protection 20 est réalisée au cours d'un test fonctionnel. Ce test peut être réalisé en observant la variation du niveau de pression mesurée par le capteur de pression 21. Avant de commander l'électrovanne de parc 13, la pression doit être inférieure à un seuil donné, par exemple 50 bars. On fait en sorte que la commande de l'électrovanne de parc 13 provoque l'ouverture de l'interrupteur 23 ce qui ramène l'électrovanne de protection 20 en position de repos si elle n'y était pas déjà, provoquant une augmentation de la pression mesurée par le capteur de pression 21 au-dessus d'un certain seuil, par exemple 100 bars. Dans le cas où ce niveau de pression ne serait pas atteint, une information est émise au système de maintenance indiquant que l'interrupteur 23 est bloqué en position fermée. Monitoring the proper operation of the electrical switch 23 and the protection solenoid valve 20 is carried out during a functional test. This test can be carried out by observing the variation in the pressure level measured by the pressure sensor 21. Before controlling the park solenoid valve 13, the pressure must be below a given threshold, for example 50 bars. It is ensured that controlling the park solenoid valve 13 causes the switch 23 to open, which returns the protection solenoid valve 20 to the rest position if it was not already there, causing an increase in the pressure measured by the pressure sensor 21 above a certain threshold, for example 100 bars. In the event that this pressure level is not reached, information is sent to the maintenance system indicating that the switch 23 is stuck in the closed position.
Le logigramme des figures 3a et 3b décrit un exemple de séquence de tests fonctionnels permettant de détecter la défaillance d'un des organes réalisant la fonction de protection de l'électrovanne de parc 13. A l'état initial les électrovannes de parc 13 et de protection 20 ne sont pas commandées (elles peuvent cependant être défaillantes en étant bloquées ouvertes ou fermées) . Durant les tests fonctionnels, les deux électrovannes sont successivement commandées et décommandées selon une séquence dépendant de la pression dans les freins (supérieure à une pression seuil Ps ou au contraire inférieure à une pression minimale Pm, avec typiquement Ps=100 bars, Pm=5 bars) . Si l'électrovanne de parc 13 n'est pas défaillante, il faut en effet la commander pour constater de la pression dans les freins (sauf bien entendu si le circuit de freinage est lui-même défaillant) . La séquence illustrée permet de repérer des pannes de l'électrovanne de parc 13, de l'électrovanne de protection 20, et de l'interrupteur 23. Cette séquence est exécutée par exemple à chaque mise en route de l'aéronef, de sorte que le pilote est informé d'une éventuelle panne avant que celle-ci ait pu engendrer une conséquence fâcheuse. The flowchart of Figures 3a and 3b describes an example of a functional test sequence for detecting the failure of one of the components performing the protection function of the parking solenoid valve 13. In the initial state, the parking solenoid valves 13 and the protection solenoid valve 20 are not controlled (they can however be faulty by being stuck open or closed). During the functional tests, the two solenoid valves are successively controlled and de-controlled according to a sequence depending on the pressure in the brakes (greater than a threshold pressure Ps or on the contrary less than a minimum pressure Pm, with typically Ps=100 bars, Pm=5 bars). If the park solenoid valve 13 is not faulty, it must in fact be controlled to detect pressure in the brakes (unless of course the brake circuit itself is faulty). The sequence illustrated makes it possible to identify faults in the park solenoid valve 13, the protection solenoid valve 20, and the switch 23. This sequence is executed for example each time the aircraft is started, so that the pilot is informed of a possible fault before it can cause an unfortunate consequence.
Selon une variante de mise en œuvre de l'invention illustrée à la figure 4, on remplace l'électrovanne de protection 20 trois voies/deux positions par une électrovanne de protection 20' deux voies/deux positions. Cette solution alternative offre l'avantage d' ôter un chemin de fuite entre le port d'alimentation et le port de retour, ce qui permet d'optimiser le dimensionnement de l'accumulateur hydraulique. Un capteur de pression 21' est de préférence disposé entre les deux électrovannes pour aider à la détection des pannes. According to an alternative embodiment of the invention illustrated in FIG. 4, the three-way/two-position protection solenoid valve 20 is replaced by a two-way/two-position protection solenoid valve 20'. This alternative solution offers the advantage of removing a leak path between the supply port and the return port, which makes it possible to optimize the sizing of the hydraulic accumulator. A pressure sensor 21' is preferably arranged between the two solenoid valves to help detect failures.
Selon une autre variante de mise en œuvre de l'invention illustrée à la figure 5, on positionne l'électrovanne de protection 20' ' toujours en série avec l'électrovanne de parc 13, mais cette fois-ci en aval de cette dernière. Un capteur de pression 21' ' est de préférence disposé entre les deux électrovannes pour aider à la détection des pannes . According to another variant of implementation of the invention illustrated in FIG. 5, the protection solenoid valve 20'' is positioned still in series with the park solenoid valve 13, but this time downstream of the latter. A pressure sensor 21'' is preferably arranged between the two solenoid valves to help detect faults.
Selon encore une autre variante de mise en œuvre de l'invention, on utilise directement les capteurs de pression 10a, 10b utilisés pour la fonction anti-patinage pour fournir une mesure de pression permettant de surveiller le bon fonctionnement des électrovannes de parc 13 et de protection 20, évitant ainsi l'installation du capteur de pression 21. According to yet another variant implementation of the invention, the pressure sensors 10a, 10b used for the anti-skid function are used directly to provide a pressure measurement making it possible to monitor the proper operation of the park solenoid valves 13 and protection 20, thus avoiding the installation of the pressure sensor 21.
La protection apportée par l'électrovanne de protec- tion 20, en combinaison ou non avec l'interrupteur commandé 23, permet donc d'éviter qu'une panne simple de l'électrovanne de parc 13 ne conduise à une situation de freinage non désirée ou toute autre situation catastrophique. On peut donc dès lors se contenter d'une électrovanne de parc à actionnement simple. The protection provided by the protective solenoid valve 20, in combination or not with the controlled switch 23, therefore makes it possible to prevent a simple failure of the parking solenoid valve 13 from leading to an unwanted braking situation or any other catastrophic situation. It is therefore possible to be satisfied with a single-actuated parking solenoid valve.
L'invention n'est pas limitée à ce qui vient d'être décrit, mais englobe au contraire tout variante entrant dans le cadre défini par les revendications. The invention is not limited to what has just been described, but on the contrary encompasses any variant falling within the scope defined by the claims.
En particulier, bien qu'ici les exemples illustrés sont relatifs à des aéronefs à deux freins, il va de soi que l'invention s'applique à des aéronefs ayant un nombre plus important de freins. In particular, although the examples illustrated here relate to aircraft with two brakes, it goes without saying that the invention applies to aircraft with a greater number of brakes.
Claims
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP24730376.1A EP4719843A1 (en) | 2023-06-05 | 2024-06-04 | Method for securing a parking function in an aircraft braking system |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR2305631A FR3149298A1 (en) | 2023-06-05 | 2023-06-05 | Method for securing a park function in an aircraft braking system |
| FR2305631 | 2023-06-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2024251750A1 true WO2024251750A1 (en) | 2024-12-12 |
Family
ID=88207440
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2024/065362 Ceased WO2024251750A1 (en) | 2023-06-05 | 2024-06-04 | Method for securing a parking function in an aircraft braking system |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP4719843A1 (en) |
| FR (1) | FR3149298A1 (en) |
| WO (1) | WO2024251750A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2626013A (en) * | 2023-01-05 | 2024-07-10 | Airbus Operations Ltd | Control device and method for an aircraft |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4251115A (en) * | 1973-04-02 | 1981-02-17 | Crane Co. | Hydraulic braking system |
| US20110187180A1 (en) * | 2010-02-03 | 2011-08-04 | Messier-Bugatti | Hydraulic braking architecture for aircraft having brakes with half-cavities |
| EP4147922A1 (en) * | 2021-09-09 | 2023-03-15 | Goodrich Corporation | Systems and methods to detect shut off valve failure for improved uncommanded braking |
-
2023
- 2023-06-05 FR FR2305631A patent/FR3149298A1/en active Pending
-
2024
- 2024-06-04 WO PCT/EP2024/065362 patent/WO2024251750A1/en not_active Ceased
- 2024-06-04 EP EP24730376.1A patent/EP4719843A1/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4251115A (en) * | 1973-04-02 | 1981-02-17 | Crane Co. | Hydraulic braking system |
| US20110187180A1 (en) * | 2010-02-03 | 2011-08-04 | Messier-Bugatti | Hydraulic braking architecture for aircraft having brakes with half-cavities |
| EP4147922A1 (en) * | 2021-09-09 | 2023-03-15 | Goodrich Corporation | Systems and methods to detect shut off valve failure for improved uncommanded braking |
Also Published As
| Publication number | Publication date |
|---|---|
| EP4719843A1 (en) | 2026-04-08 |
| FR3149298A1 (en) | 2024-12-06 |
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