Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02K—JET-PROPULSION PLANTS
  • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
  • F02K1/54—Nozzles having means for reversing jet thrust
  • F02K1/76—Control or regulation of thrust reversers
  • F02K1/763—Control or regulation of thrust reversers with actuating systems or actuating devices; Arrangement of actuators for thrust reversers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
  • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
  • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2260/00—Function
  • F05D2260/40—Transmission of power
  • F05D2260/406—Transmission of power through hydraulic systems
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
  • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
  • F15B2211/7058—Rotary output members
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
  • F15B2211/715—Output members, e.g. hydraulic motors or cylinders or control therefor having braking means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
  • F15B2211/76—Control of force or torque of the output member
  • F15B2211/763—Control of torque of the output member by means of a variable capacity motor, i.e. by a secondary control on the motor

Definitions

• Turbojet thrust reverser hydraulic control having a variable displacement machine
• the present invention relates to a hydraulic control of a thrust reverser for an aircraft nacelle receiving a turbojet, and an aircraft nacelle equipped with such a hydraulic control.
• the engine sets for the aircraft generally comprise a nacelle forming a generally circular outer envelope, comprising inside a turbojet arranged along the axis of this nacelle.
• the turbojet engine receives fresh air from the upstream or front side, and rejects on the downstream or rear side hot gases from the combustion of fuel, which give a certain thrust.
• turbofan engines have around this turbojet fan blades generating a large secondary flow of cold air along an annular vein passing between the engine and the nacelle, which adds a high thrust.
• Some nacelles include a thrust reversal system that closes at least part of the annular cold air duct, and rejects the secondary flow forward to generate a braking thrust of the aircraft.
• One type of thrust reverser known presented in particular by the document FR-A1 -2758161, comprises rear mobile covers called “Trans-cowl", sliding axially backwards under the effect of jacks by deploying flaps in the ring vein in order to close most of this vein.
• the flaps return the flow of cold air radially outward through grids discovered by the movable hoods during their sliding, including blades that direct the flow forward.
• the thrust reversers grids were motorized by a pneumatic engine using a pressure supplied by the compressor stages of the turbojet engine.
• the pneumatic motor drives actuators with shafts each comprising a mechanical jack using a ball screw-nut system, which makes it possible to synchronize all of these cylinders to obtain a translation of the covers.
• This type of engine is no longer produced because it poses several problems, including a large size of the air motor, a highly variable available pressure depending on the speed of the turbojet engine, a compressibility of the air supply energy that does not give sufficiently responsive control of the engine, and dependence on environmental conditions, such as frost.
• Another type of known motorization comprises an electric motor which as for the pneumatic motor, motorizes a kinematic chain synchronously driving the various actuators. This solution requires the provision of a significant electrical power that all aircraft are not able to provide.
• Another type of known motorization comprises several linear hydraulic actuators fed by a source of pressurized fluid, having internal screws which allow synchronization of these different actuators. This solution is relatively heavy, complicated, and consumes a lot of hydraulic flow of the aircraft.
• the present invention is intended to avoid these disadvantages of the prior art.
• a hydraulic thrust reverser control for a turbojet engine nacelle comprising at least one hydraulic machine powered by a pressure source, which drives actuators performing the travel of the inverter, characterized in that this machine hydraulics has a variable displacement.
• An advantage of this hydraulic control is that both high torque at engine start can be achieved using maximum displacement, and high speed with reduced torque for constant speed operation, using lower displacement which decreases fluid consumption.
• the hydraulic control according to the invention may further comprise one or more of the following features, which may be combined with one another.
• the hydraulic control comprises a brake controlled by a hydraulic cylinder, blocking the actuator stroke, which is closed in the absence of hydraulic pressure. This ensures safety by blocking the inverter in the absence of hydraulic pressure.
• the hydraulic brake control cylinder can be powered by a normally closed valve in the absence of control. This ensures safety by blocking the inverter in case of failure of the control of the hydraulic circuit.
• the mechanical connection between the hydraulic machine and the actuators comprises flexible shafts. A synchronization of different actuators distributed around the nacelle of the turbojet engine is thus performed in a simple manner.
• the mechanical connection between the hydraulic machine and the actuators comprises a manual control means for these actuators.
• This means allows interventions by moving the inverter when his control system is stopped.
• the hydraulic control comprising two pressure lines supplying the hydraulic machine, comprises a balancing valve arranged on one of these lines, which is controlled by the pressure of the other line, in order to automatically adapt a restriction of passage of the fluid on the output of this machine when it works as a generator.
• the hydraulic control comprises a sequence valve which in a controlled position connects a pressure line of the hydraulic machine to the pressure source, and the other pressure line to a low pressure reservoir, and in another reverse controlled position these links pressure lines.
• the sequence valve has passage restrictions allowing a gradual pressure drop of the pressure in this control. This ensures little loss of pressure in the control circuit during the transition from a controlled position to another, and the safety with a fall of this pressure in the absence of control of the valve.
• the hydraulic control comprises a control of the distributors for regulating the displacement of the hydraulic machine, as a function of the load pressure level of this machine. This gives a flexibility of adaptation for adjusting the displacement of the hydraulic machine.
• the hydraulic control comprises means that control in closed loop according to the measured stroke of the inverter, the displacement regulating valves which are of the proportional control type.
• This regulation principle is simple to achieve.
• control valves of the displacement can be driven more advantageously for example by pulse width modulated type "PWM".
• the invention also relates to a turbojet engine nacelle having a thrust reverser hydraulically controlled, this command having any of the preceding characteristics.
• FIG. 1 presents a hydraulic diagram for an inverter control. thrust according to the invention.
• FIG. 1 shows a hydraulic control circuit of a thrust reverser, containing a hydraulic machine 30 with variable displacement functioning as a motor to actuate the mechanism of this inverter, and as a generator by receiving a mechanical power from the thrust reverser during braking his movement.
• the hydraulic circuit receives the fluid from a source of hydraulic pressure 2 via an inlet filter 4.
• the fluid under pressure is transmitted to the circuit by a safety solenoid valve 6 which is open in an activated position to supply the hydraulic control circuit, and which is closed in the absence of a signal to ensure safety, by putting this circuit in communication with a tank at atmospheric pressure 10.
• the arrival of the pressurized fluid then passes through a sequence valve 12, which in a first controlled position ensures the supply of an upper pressure line 16 by the pressure source 2 to deliver energy to the hydraulic machine 30 working in motor, the return of the fluid to the tank 10 by a lower pressure line 18.
• the sequence valve 12 has a central rest position which connects with strong flow restrictions, the two pressure lines 16, 18 to the tank 10 to allow a gradual drop in pressure in the control circuit.
• the return to the reservoir 10 is by a pressure limiting valve 8, maintaining a pressure of 10bar in the return line, which may be the upper line 16 or lower 18 depending on the position of the sequence valve 12.
• the hydraulic machine 20 comprises a control of its variable displacement, which is not shown in this diagram.
• a leakage return 20 recovers the leaks of the hydraulic machine 30 and its variable displacement control, to drive them to the tank 10.
• Two nonreturn valves 22, 24 comprising a calibration spring calibrated at 0.5 bar, are arranged between the leakage return 20 and the upper pressure line 16 as well as the lower pressure line 18, in order to avoid an overpressure in this leakage return by discharging the fluid in one of these two pressure lines.
• the hydraulic machine 20 drives, by means of a speed reduction gear 32, directly a first mechanical jack of the screw-ball nut type 36, and by flexible shafts 34 making it possible to go around the nacelle of the turbojet engine, other mechanical cylinders. similar 36 which then have a synchronized movement. This gives a linear displacement of the thrust reverser, which remains parallel to the axis of the nacelle.
• a manual control device 46 makes it possible to drive the flexible shafts 34 directly via a control handle in order to maneuver the mechanical cylinders 36 in the event of a stopping or breakdown of the motorization. This ensures the possibility of intervention or maintenance in all cases.
• a mechanical brake 38 comprising stacked brake disks, disposed at the end of the line of the flexible shafts 34, is controlled by a jack hydraulic 40 comprising a load spring which constantly keeps the brake closed in the absence of hydraulic pressure.
• a hydraulic valve 42 comprising at rest a closed position and active an open position, controls this brake.
• a hydraulic bypass valve 50 arranged in parallel with the hydraulic machine 30, comprises at rest an open position which gives a free passage of the fluid between the upper pressure line 16 and the lower pressure line 18, and in the closed position a interruption of this passage allowing this machine to work.
• a balancing valve 52 arranged between the lower connection of the hydraulic machine 30 and the lower pressure line 18 is controlled by the pressure of the upper line 16 in order to automatically adapt a restriction of passage of the fluid on the outlet of this machine when it works generator, depending on its output pressure and the pressure of the top line that feeds. Automatic braking of the hydraulic machine 30 working as a generator is thus automatically performed, in order to dissipate a braking power in the pressure return towards the reservoir 10.
• a balancing valve can be arranged in the same manner on the upper pressure line 16 at the inlet of the hydraulic machine 30 to retain the load on this machine in the event of a stop, without applying the mechanical brake 38. .
• This control circuit comprises at the beginning of the movement of the inverter which is deployed, the positioning of the hydraulic machine 30 on a large displacement in order to obtain a high starting torque with the supply by the upper pressure line. 16, then the passage on a reduced displacement to obtain a high speed of movement with low fluid consumption.
• this movement we obtain a closure of the flaps of the inverter arranged in the annular cold air duct, which return the flow through the deflection means to the front of the aircraft.
• the thrust of the cold airflow on the flaps generates a heavy load on these flaps which tends to close them, their strokes then cause the hydraulic machine 30 which passes into the operating mode generator, with a braking of this machine by the balancing valve 52 arranged at the output.
• the stresses at the end of the stroke of the inverter are greatly reduced, particularly after high speeds of translation in the middle of the stroke, due to the high displacement position of the hydraulic machine 30 delivering a high braking torque.
• the distributor for adjusting the displacement of the hydraulic machine 30 is regulated as a function of the load pressure level of this machine, which provides flexibility of adaptation to simplify the control of the speed ramp originally planned.
• a displacement control valve which is less precise than a servo valve, comprising proportionally controlled solenoids which can be controlled in a closed loop as a function of the measured travel of the inverter by a sensor. which measures a rotation or a displacement of a mechanical element related to the displacement of this inverter.
• this distributor for adjusting the displacement by means of modulated width pulses of the "PWM" (Pulse Width Modulation) type.
• proportional control valves are generally less accurate than slave valves, which is offset by the greater flexibility of control given by the displacement variation of the hydraulic machine 30.
• a more complex servocontrol consists in measuring the control pressure of the variable displacement of the hydraulic machine 30, in order to more precisely control this displacement adjustment.
• variable displacement motors may be used in the context of the invention.
• the use of multiple engines has multiple advantages, including having redundancy to increase the operational availability of the function.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Fluid-Pressure Circuits (AREA)
• Control Of Turbines (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=50424597

Family Applications (1)

Country Status (4)

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Citations (1)

Family Cites Families (7)

• 2014
  • 2014-01-27 FR FR1450651A patent/FR3016928B1/fr active Active
• 2015
  • 2015-01-27 WO PCT/FR2015/050181 patent/WO2015110770A1/fr active Application Filing
  • 2015-01-27 EP EP15706861.0A patent/EP3099920A1/de not_active Withdrawn
• 2016
  • 2016-07-26 US US15/219,711 patent/US20160333824A1/en not_active Abandoned

Patent Citations (1)

Non-Patent Citations (1)

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