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
  • F02K1/56—Reversing jet main flow
  • F02K1/566—Reversing jet main flow by blocking the rearward discharge by means of a translatable member
• • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• Thrust reverser for an aircraft turbojet with a reduced number of actuators
• the present invention relates to a thrust reverser for an aircraft turbojet, with a reduced number of actuators.
• An airplane is driven by several turbojets each housed in a nacelle for channeling the air flows generated by the turbojet engine which also houses a set of actuators providing various functions when the turbojet engine is in operation or stopped.
• actuating devices may include, in particular, a mechanical thrust reversal system.
• a nacelle generally has a tubular structure comprising an air inlet upstream of the turbojet engine, a median section intended to surround a fan of the turbojet engine, a downstream section housing thrust reverser means and intended to surround the combustion chamber of the turbojet engine. , and is generally terminated by an ejection nozzle whose output is located downstream of the turbojet engine.
• Modern nacelles are intended to house a turbofan engine capable of generating, by means of the fan blades, an air flow part of which, called a hot or primary flow, circulates in the combustion chamber of the turbojet engine, and of which the other part, called cold or secondary flow, circulates outside the turbojet through an annular passage, also called vein, formed between a shroud of the turbojet engine and u nn inner wall of the nacel.
• the two air fl ows are ejected from the turbojet engine from the rear of the nacelle.
• the role of a thrust reverser is, during the landing of an aircraft, to improve the braking capacity thereof by redirecting forward at least a portion of the thrust generated by the turbojet engine.
• the inverter obstructs the cold flow vein and directs the latter towards the front of the nacelle, thereby generating a counter-thrust which is added to the braking of the wheels of the aircraft.
• an inverter comprises movable covers (or doors) moved between a closed position or “direct jet” in which they close this passage and an open position or “reverse jet” in which they open.
• movable covers or doors moved between a closed position or “direct jet” in which they close this passage and an open position or “reverse jet” in which they open.
• a passage for the deviated flow in the nacelle a passage for the deviated flow.
• a thrust reverser with grids also known as a cascade reverser
• the reorientation of the air flow is performed by deflection grids, the hood having a simple sliding function to discover or cover these grids.
• the translation of the movable cowl takes place along a longitudinal axis substantially parallel to the axis of the nacelle.
• Reversed thrust flaps actuated by the sliding of the hood, allow an obstruction of the cold flow vein downstream of the deflection grids, so as to optimize the reorientation of the cold flow to the outside of the nacelle.
• the movable cowl is in one piece and slidably mounted on slideways arranged on either side of the suspension pylon of the formed assembly. by the turbojet and its nacelle.
• “Monobloc cowling” means a quasi-annular shaped cowl, extending from one side to the other of the pylon without interruption.
• Such a hood is often referred to by the Anglo-Saxon terms “O-duct”, alluding to the ferrule shape of such hood, as opposed to “D-duct”, which actually comprises two half-hoods. each extending on a half-circumference of the nacelle.
• actuators there are four or six actuators, namely respectively two or three actuators distributed on each half of the thrust reverser, on either side of the suspension pylon.
• the present invention aims to simplify these actuating means, both to reduce costs and to reduce the mass of the nacelle.
• This object of the invention is achieved with a thrust reverser with grids and with a moveable one-piece cowling comprising rails able to slide in slideways arranged on either side of a suspension pylon. comprising only two actuators disposed near said rails and able to slide said cover on said rails between its direct jet and reverse jet positions, and also comprising means able to compensate for the efforts tending to misalign said rails with respect to said slides, and thus avoiding their mutual jamming, remarkable in that said means are selected from the group comprising:
• inversion reversing flaps arranged so as to exert a thrust force on the upstream edge of the inner wall of said movable cowl.
• the thrust force present both at the opening and closing of the movable cowl, makes it possible to apply a force distributed in a substantially homogeneous manner over the entire periphery of the moving cowl which makes it possible to reduce the intensity of the aforementioned tilting torques.
• said compensating means comprise means of pressurizing the outer wall of said movable cowl: by pressurizing the outer wall of the movable cowl, whose shape is also conical, but inverted with respect to that of the inner wall of the cowl, substantially reduced the effect of the above-mentioned tilting torque;
• - Average pressurization means include a seal disposed upstream of the outer wall of said movable cover, and an absence of seal upstream of the inner wall of the movable cover: by removing the seal of the inner wall and transferring it to the outer wall, the cold air that is under pressure in the cold flow vein is allowed to fill the space between the inner and outer walls of the mobile cowl, and thus pressurize at least part of the outer wall;
• the said pressurizing means comprise a seal on the inner wall of said movable cowl, associated with a limited leak on the outer wall and at least one expansion valve located through the inner wall: the role of these pressure reducers is d ensure a pressure in the space between the inner and outer walls of the movable cowl that cancels the resultant axial forces of the movable cowl; optionally, this regulator can be controlled.
• FIG. 1 is a general schematic representation of a turbojet engine nacelle having a thrust reverser according to the invention, that is to say having a one-piece mobile cowl ("O-duct" type inverter), of which interior is seen in transparency;
• O-duct mobile cowl
• FIG. 2 is a schematic representation in longitudinal half-section of the nacelle of Figure 1;
• FIGS. 3 to 5 are longitudinal half-sectional views of the thrust reverser of the nacelle of Figures 1 and 2, in three successive positions;
• FIG. 6 shows schematically in cross section, the positioning of the two actuators of the movable cover of the thrust reverser of Figures 3 to 5;
• FIG. 7 shows schematically, in longitudinal section, the tilting torque which is subject to the movable cover
• FIG. 8 shows in a diagrammatic manner, in longitudinal section, an appropriate positioning of a seal on the movable cowl of the thrust reverser according to the invention.
• FIG. 9 schematically shows, in detail, the mechanism found in zone XII of FIG. 5.
• identical or similar references denote identical or similar organs or sets of members.
• a nacelle 1 is intended to constitute a tubular housing for a turbojet engine 3 and serves to channel the flows of hot air 5 and cold 7 generated by this turbojet engine 3, as indicated in the preamble of FIG. this description.
• This nacelle 1 is intended to be suspended from a tower 8, itself fixed under the wing of an aircraft.
• the nacelle 1 has, in general, a structure comprising an upstream section 9 forming an air inlet, a central section January 1 surrounding the fan 13 of the turbojet engine 3 and a downstream section 15 surrounding the turbojet engine 3.
• the downstream section 15 comprises an external structure 17 comprising a thrust reverser device and an internal structure 19 for refitting the engine 3 of the turbojet engine defining with the external structure 17 the stream of the cold stream 7, in the case of the turbojet nacelle double flow as presented here.
• the thrust reverser device comprises a cover 23 mounted to move in translation in a direction substantially parallel to the longitudinal axis A of the nacelle 1.
• This cover 23 is able to pass alternately from a closed position (position shown in Figures 1 and 2) in which it ensures the aerodynamic continuity of the lines of the downstream section 15 of the nacelle 1 and covers grids 25 of flow deflection of air, to an open position in which it opens a passage in the nacelle 1 by discovering these deflection grids 25.
• the movable cover 23 is in one piece, that is to say it comprises a single one-piece mobile cover, of quasi-annular shape, extending from one side to the other. another of the pylon 8 without interruption (mobile cowl called "O-duct").
• the deflection grids 25 each have a plurality of deflector vanes.
• the downstream section 15 may further comprise a front frame 27 which extends the hood 23 upstream and ensures the attachment of the downstream section 15 with the central section 1 1 surrounding the fan 13 of the turbojet engine.
• the translation of the movable cowl 23 downstream of the nacelle releases therein an opening through which the cold jet of the turbojet engine can escape at least partially, this portion of the flow being reoriented towards the front of the nacelle by the deflection grids 25, thereby generating a counter-thrust capable of contributing to the braking of the aircraft.
• the orientation of the cold flow towards the deflection grids 25 is effected by a plurality of inversion flaps 29 (see FIGS. 3 to 5 and 9), distributed on the inner circumference of the movable cowl 23, each mounted pivoting between a retracted position. (see FIGS. 3 and 4) in which these flaps 29 ensure the internal aerodynamic continuity of the cold flow duct 7 and an extended position in which, in a thrust reversal situation, they at least partially close this vein and deflect the flow cold through deflection grids 25.
• the thrust reverser can be seen in the "direct jet” position, that is to say in the position where the cold flow 7 flows directly from upstream to downstream of the nacelle: this position corresponds to the cruise flight situation of the aircraft.
• the thrust reversal grids 25 are of the retractable type, that is to say that they are capable of sliding from an upstream position (FIGS. 3 and 4) at a downstream position (FIG. 5), under the effect of the opening of the movable cowl 23.
• the downstream sliding movement of the thrust reversal grids 25 is effected by abutments 31 arranged appropriately on the upstream edge of the outer wall 33 of the movable cowl 23.
• the thrust reversing flaps 29 are each mounted pivoting and sliding inside grooves 34 integral with the thrust reversal grids 25.
• a first connecting rod 35 connects the pivoting and sliding end of each flap 29 to the fixed front frame 27, or to any other fixed structure, and a second connecting rod 37 is articulated on the one hand substantially mid-length of the inverting flap. thrust 29, and secondly, in the upstream zone of the thrust reversal grids 25.
• the first link 35 has the effect of sliding the point of articulation of the end of the thrust reversal flap 29 inside the groove 34, allowing the extraction of this thrust reversal shutter of the cavity defined by the walls 33 and 41.
• the second connecting rod 37 has the effect of pivoting the thrust reverser flap 29 to its closed position of the cold flow stream 7, visible in FIG. 5, making it possible to orient this cold flow through the thrust reversal grids 25, upstream of the nacelle 1.
• the actuating means of the movable cowl 23, permitting its sliding from one to the other of the positions visible in FIGS. 3 to 5, are schematically represented in FIG. 6: these means comprise two single actuators 43 a and 43b disposed in the upper part of the movable cowl (that is to say upwards of the drawing board 3/4 appended hereto), on either side of the suspension pylon 8.
• actuators may be hydraulic cylinders, or actuators of the mechanical-electrical type, such as worm and nut systems. Due to the substantially frustoconical shape of the inner wall 41 of the movable cowl 23, which shape flares downstream of the nacelle, the resultant RP of the cold air pressure forces on this inner wall is directed towards the upstream of the nacelle, as can be seen in FIG. 7, when the mobile cowl is in the "direct jet" position.
• This resultant RP therefore has the effect of generating a tilting torque with the resultant RA of the forces exerted by the actuators 43a and 43b during the opening of the movable cowl 23.
• This tilting torque may have the consequence of blocking the rails (not shown) disposed in the upper part of the movable cowl 23, and allowing the sliding of the mobile cowl in two slides (not shown) d isposées on both sides suspension pylon 8.
• the cold air 7 under pressure in the cold air duct of the nacelle fills the cavity delimited by the external and internal walls 33 of the movable cowl 23.
• this regulator is to ensuring a pressure in the space between the inner walls 41 and outer 43 of the movable cowl, which cancels the resultant axial forces of the movable cowl; optionally, this regulator can be controlled.
• Another solution to reduce these risks of jamming and jamming may be to attach a cable 55 to the end of each rail 45 of the movable cover 23, as can be seen in Figures 10 and 1 1.
• This circumferential distribution of the force makes it possible to counteract the tilting torque generated by the asymmetrical positioning of the actuators 43a and 43b, and thus actively contributes to reducing the risk of jamming and jamming.
• the present invention provides a thrust reverser particularly simplified design and lightened, through the use of two actuators only, arranged on either side of the suspension pylon of Platform.
• This limitation of the number of actuators, as well as their particular positioning, poses difficulties resulting from the tilting torques generated on the one hand by the pressurization of the cold air in the nacelle, and on the other hand by the asymmetric forces generated by these actuators, when opening and closing the movable hood.
• the aforementioned means used alone or in combination, are used to compensate for the tilting forces of the movable cover of the thrust reverser.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Platform Screen Doors And Railroad Systems (AREA)
• Control Of Turbines (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=43928436

Family Applications (1)

Country Status (8)

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Family Cites Families (8)

• 2010
  • 2010-11-03 FR FR1059031A patent/FR2966882B1/fr not_active Expired - Fee Related
• 2011
  • 2011-10-28 EP EP11832145.4A patent/EP2635789A2/de not_active Withdrawn
  • 2011-10-28 CN CN2011800527372A patent/CN103201491A/zh active Pending
  • 2011-10-28 WO PCT/FR2011/052544 patent/WO2012059677A2/fr active Application Filing
  • 2011-10-28 RU RU2013124521/06A patent/RU2013124521A/ru not_active Application Discontinuation
  • 2011-10-28 BR BR112013009356A patent/BR112013009356A2/pt not_active IP Right Cessation
  • 2011-10-28 CA CA2814384A patent/CA2814384A1/fr not_active Abandoned
• 2013
  • 2013-05-02 US US13/875,856 patent/US20140131479A1/en not_active Abandoned

Non-Patent Citations (1)

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