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
  • F02K1/64—Reversing fan flow
  • F02K1/70—Reversing fan flow using thrust reverser flaps or doors mounted on the fan housing
  • F02K1/72—Reversing fan flow using thrust reverser flaps or doors mounted on the fan housing the aft end of the fan housing being movable to uncover openings in the fan housing for the reversed flow
• • 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

Definitions

• the present invention relates to a thrust reverser with grids for turbojet nacelle
• the role of a thrust reverser during the landing of an aircraft is to improve the braking capacity of the latter by redirecting forward at least a portion of the thrust generated by the turbojet engine.
• the inverter obstructs the gas ejection nozzle and directs the ejection flow of the engine towards the front of the nacelle, thereby generating a counter-thrust which is added to the braking of the wheels of the engine. 'plane.
• the structure of an inverter comprises movable covers movable between, on the one hand, an extended position in which they open in the nacelle a passage intended for the deflected flow, and on the other hand, a position retraction in which they close this passage.
• These movable hoods may furthermore fulfill a deflection function or simply the activation of other deflection means.
• the movable cowls slide along rails so that when backing up during the opening phase, they discover deflection blade grids disposed in the thickness of the nacelle.
• a linkage system connects the movable hood to blocking doors that expand within the ejection channel and block the output in direct flow.
• each movable hood pivots so as to block the flow and deflect it and is therefore active in this reorientation.
• these mobile covers are actuated by hydraulic or mechanical actuators with pneumatic or electric control.
• the two primary locks hold each mobile cowl in the retracted position and resume the efforts to translate said movable cowl. These locks are redundant to cover a possible failure of one of the primary locks, each lock being sized to fully resume the sum of efforts to translate the movable cover.
• the function of the tertiary lock is that of a backup lock system which is requested to resume efforts to translate the movable cowl only in case of failure of the two primary locks.
• the thrust reverser systems are provided with three separate control unlocking lines.
• the aerodynamic loads encountered in flight fatigue locks and further pushes are also exerted on the ground locks during maintenance operations when it is necessary to manually unlock these locks.
• the electrically operated thrust reverser systems are provided with helical link actuators, for example of the "ball screw” type, and are actuated by electric motors in direct contact with the actuator or by means of transmission cables. mechanical transmission. These rotary power transmission devices induce dimensional inertial loads for holding the actuator stops and the inverter structure and require the use of deceleration strategies of the electrical control in the end-of-travel zones.
• the present invention aims to provide a thrust reversal system generally more reliable and less subject to premature wear of some of its mechanical components.
• the present invention relates to a thrust reverser for a turbojet engine nacelle comprising at least one movable cowl mounted on a fixed inverter structure between a closed position in which they provide the aerodynamic continuity of the nacelle and deactivate means deflecting at least a portion of the air flow and an opening position in which they open a passage in the nacelle and activate said deflection means, each movable cover being able to be moved between these two positions by at least an actuating means, characterized in that the actuating means are associated with at least one mechanical braking means of said actuating means.
• the establishment of mechanical braking means of the mobile cover actuating means allows, on the one hand, to have additional security in the event of engine or electronic failure, but also to have a system of retaining the actuating means which can then be slightly claimed to meet the braking means.
• This last characteristic makes it possible to induce in the thrust reversal system a preload when the movable covers are in the closed position.
• this preload allows better absorption of vibrations and relative movements between parts, which reduces mechanical fatigue.
• the braking means contributes substantially to maintaining the inverter in the closed position.
• this preload makes it possible to reduce the tensions exerted on the means for locking the half-parts to one another, which makes it easier to unlock and reduces fatigue wear.
• the braking means may allow stop the system and avoid a violent arrival of mobile covers on the ultimate stops.
• the actuating means are electric actuating means of the electric cylinders type capable of being driven by at least one associated electric motor.
• the braking means are implemented at the level of the electric motor.
• the braking means are arranged to act at a drive shaft of the electric motor.
• the actuating means are driven through flexible transmission shafts.
• the braking means are arranged at the level of the flexible transmission shafts. More particularly, the brakes may be of jaw type coming to grip the drive shaft
• the inverter is a gate-type inverter.
• the braking means are associated with synchronization means between them.
• the braking means are static braking means having an engagement position by default current.
• the braking means are disengaged manually.
• the present invention also relates to a nacelle for a turbojet, characterized in that it comprises at least one thrust reverser according to the invention
• Figure 1 is a partial schematic perspective view of a nacelle incorporating a thrust reverser grids.
• Figure 2 is a schematic representation of the movable covers and their actuating system.
• Figure 3 is a schematic representation of the drive system of Figure 2.
• a thrust reverser 1 with grids generally has a structure comprising two semicircular movable hoods 2 slidable along rails (not shown) to discover deflection blade grids placed between the movable hoods 2 and a passage section. the airflow to deflect.
• Locking doors are arranged inside the structure so as to pivot and move from a position in which they do not interfere with the passage of the air flow 4 to a position in which they block this passage.
• these are mechanically connected to the movable cover 2 by hinges and to the fixed structure by a system of connecting rods.
• the displacement of the mobile covers 2 on the rails along the outside of the structure is provided by a set of jacks 6a, 6b mounted on a front frame inside which are housed an electric motor 7 and flexible transmission shafts. ⁇ a, ⁇ b respectively connected to the jacks 6a, 6b to actuate them.
• each movable cowl 2 can be translated along its rails under the action of three jacks 6a, 6b, comprising a central jack 6a and two additional jacks 6b, actuated by a single electric motor 7 connected to a control interface 9.
• the power delivered by the electric motor 7 is first distributed to the central cylinders 6a via two flexible transmission shafts ⁇ a, then to the additional cylinders 6b by flexible transmission shafts ⁇ b.
• each central cylinder 6a redistributing the movement to the additional cylinders 6b is equipped with a manual control box 9 allowing an opening or closing Manual of the corresponding mobile cover 2 during maintenance operations.
• the drive means of the two movable covers 2 are associated with braking means.
• Figures 2 and 3 show brake blocks 10 arranged on either side of the motor 7 at a drive shaft for the right cover and a drive shaft for the left cover.
• the braking means used may be, for example a static brake with a lack of current using a type of multi-disc brakes, spring-loaded and / or electrically unlockable by an integrated linear actuator.
• the brake is released and provides a precharge of the flexible transmission chain to avoid contact with the mechanical locks housed for example in the actuators
• the braking means 10 will be controlled on unlocking by one or more control units (not shown) when the thrust reversal is selected.
• the static brake can be used to immobilize the moving hoods 2 in emergencies and to avoid dynamic impacts in the event of loss of end-of-travel control.
• the brake holds the movable covers 2 on the stops and no longer on the lower locks. The unlocking of these can therefore be performed without load and therefore without wear on said locks.
• a manually operated brake inhibit mechanism is also installed.
• This mechanism can be a simple lever against the thrust of the springs, for example, and thus release the disks. Actuation of this lever will freely drive the movable covers 2 and then secure them in the desired position by re-engaging the brake.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Wind Motors (AREA)
• Braking Arrangements (AREA)
• Transmission Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (8)

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Family Cites Families (7)

• 2007
  • 2007-08-20 FR FR0705901A patent/FR2920196B1/fr active Active
• 2008
  • 2008-06-18 US US12/674,104 patent/US20100212287A1/en not_active Abandoned
  • 2008-06-18 RU RU2010109787/06A patent/RU2010109787A/ru unknown
  • 2008-06-18 BR BRPI0813049-3A2A patent/BRPI0813049A2/pt not_active IP Right Cessation
  • 2008-06-18 WO PCT/FR2008/000845 patent/WO2009024659A1/fr not_active Ceased
  • 2008-06-18 EP EP08827585A patent/EP2179164A1/de not_active Withdrawn
  • 2008-06-18 CA CA2696231A patent/CA2696231A1/fr not_active Abandoned
  • 2008-06-18 CN CN200880102799A patent/CN101784781A/zh active Pending

Non-Patent Citations (1)

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