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
  • 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
  • F05D2260/403—Transmission of power through the shape of the drive components
• • 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
  • F05D2260/84—Redundancy

Definitions

• the present invention relates to an actuator for an aircraft turbojet engine nacelle.
• An aircraft is driven by one or more turbojets each housed in a nacel serving it to channel the flows of a ir generated by the turbojet engine which also houses a set of actuators providing various functions, when the turbojet engine is in operation or at a standstill.
• actuating devices may include, in particular, a mechanical thrust reverser system whose role is to improve the braking capacity thereof by redirecting forward at least a portion of the thrust generated by the turbojet engine. when landing an airplane.
• 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 an inverter, otherwise known as a thrust reverser device, and intended for surround the gas generator of the turbojet, 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 engine through an annulai passage, also called é ve in in, formed between renovations of the turbojet engine and the inner walls of the nacelle.
• the two air flows are ejected from the turbojet engine from the rear of the nacelle.
• 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 movable between a closed position or “direct jet” in which they close this passage and an open position or “reverse jet” in which they open in the nacelle a passage for the deviated flow.
• These hoods can perform a function of deflection or simply activation of other means of deflection.
• the translation of the movable cowl takes place along a longitudinal axis substantially parallel to the axis of the nacelle.
• Each actuator is typically mounted between a fixed front part of the nacelle, for example on a front frame of the thrust reverser, and a movable rear part of the nacelle.
• Such an actuator 1 comprises:
• a body 2 which is fixed on the front part of the platform by a front attachment system 3 made in the form of a fixing bracket,
• a worm 4 which extends axially along an axis A of work and which is rotatably mounted in the body 2,
• control shaft 5 forming a drive system for rotating the worm 4
• a tubular actuating arm 7 (the upper half having been hidden for greater visibility) which extends axially from a front section secured to the nut 6, to a rear section connected to the movable rear part of the nacelle by a rear attachment system 8, in particular of the bracket or bracket type, the actuating arm 7 being slidably driven by the nut 6 along the working axis A, between a front position in which the arm actuator 7 is retracted and a rear position in which the actuating arm 7 is deployed.
• balls are interposed between the threads of the worm 4 and those of the nut 6, so as to reduce friction, so that this type of actuator is commonly referred to as a "ball screw” .
• the control shaft comprises a pinion, for example with oblique teeth, which cooperates with a master pinion itself driven directly or indirectly by an electric motor. Under the action of this electric motor, the worm 4 pivots in one direction or the other, thus translating the nut 6 axially in one direction or the other, and thus lengthen or retract the arm of actuation 7.
• This force here passes through the front attachment system 3, the body 2, the worm 4, the nut 6, the actuating arm 7 and the rear attachment system 8.
• the invention aims in particular to provide an actuator offering greater reliability.
• the invention proposes an actuator for an aircraft turbojet engine nacelle, which is interposed between a fixed front part of the nacelle and a movable rear part of the nacelle, the actuator comprising:
• a body which is adapted to be fixed on the front part of the platform by a main front attachment system
• a main actuating arm which extends axially from a front section secured to the main nut, to a rear section adapted to be connected to the movable rear part of the nacel by a system of main rear attachment, said arm being slidably driven by the main nut along the working axis, between a front position in which the main arm is retracted and a rear position in which the main arm is deployed, characterized in that the actuator comprises a secondary actuating arm which extends axially from a rear section adapted to be connected to the movable rear part of the nacelle, to a front section secured to the main nut, the secondary actuating arm being designed to overcome a failure of the main arm.
• the secondary arm allows continuity of operation of the actuator in the event of failure or rupture of the main arm of the actuator.
• the main front and rear attachment systems may be of the type bracket, fitting or mounting bracket, in particular by screwing, riveting, or other equivalent type of attachment.
• the rotary drive device may be of the type comprising a motor, for example electric and for example rotary, mechanically coupled to the worm to drive it in rotation.
• the main arm forms a first half-tube and the secondary arm forms a second complementary half-tube, said half-tubes extend along the working axis and are superposed and fixed together to form a tube axial in which the worm is arranged.
• This design makes it possible in particular not to increase the size of the actuator relative to the type of existing actuator.
• first half-tube and the second half-tube each comprise a pair of complementary radial fins which extend axially and which cooperate with each other to fix the first half-tube on the second half-tube.
• main arm and the secondary arm are symmetrical along an axial plane of symmetry passing through the working axis.
• the actuator comprises a secondary nut which is screwed on the worm and which is secured to the secondary arm to allow the driving of the secondary arm sliding along the working axis, between a front position in which the secondary arm is retracted and a rear position in which the secondary arm is deployed.
• the secondary nut is used to transmit a force between the secondary arm and the screw in case of breakage of the main nut.
• the main rear attachment system comprises a main leg which is formed by a first portion secured to the main arm and a second portion secured to the secondary arm.
• the actuator is equipped with a secondary rear attachment system comprising a secondary lug which is formed by a first portion secured to the main arm and a second portion secured to the secondary arm.
• This feature allows the secondary leg to double the force path, the first portion and the second portion being each adapted to transmit a force between the associated arm and the movable rear portion of the nacelle.
• the actuator comprises a secondary front attachment system which is designed to connect the front part of the nacelle to the actuator to allow a passage of force between the front part of the nacelle and the actuator, and which is designed to overcome a failure of the main front attachment system.
• the actuator comprises a reinforcing rod which extends axially along the working axis, and which comprises a front section connected to the body of the actuator and a rear section threaded into a bore of the worm for hold the screw axially in case of breakage of the screw.
• the worm may transmit a tensile force.
• the secondary front attachment system includes a secondary front fitting which is adapted to be attached to the forward portion of the pod and which is connected to the body via the front portion of the reinforcing rod.
• the front section of the rod collaborates with the secondary fitting so as to allow mounting of the actuator from the front without disassembly of said secondary fitting.
• FIG. 1 is a partial perspective view, which illustrates a ball screw type actuator according to the prior art
• FIG. 2 is a diagrammatic perspective view, which represents a turbojet engine nacelle equipped with an actuator according to the invention
• FIG. 3 is a cut-away perspective view illustrating the actuator of FIG. 2 comprising a main arm and a secondary arm;
• FIG. 4 is a detailed perspective view, which illustrates the main front attachment system and the secondary attachment system of the actuator
• FIG. 5 is an exploded perspective view of detail, which illustrates the main arm and the secondary arm of FIG. 3 according to the invention
• FIG. 6 is an axial sectional view, which illustrates the main arm and the secondary arm of Figure 3 in a retracted position
• FIG. 7 is a partial perspective view, which illustrates an alternative embodiment of the actuator according to the invention.
• FIG. 2 shows a nacelle 1 0 for an aircraft turbojet, which extends axially along a longitudinal axis A.
• the nacelle 10 has a fixed front portion 12 which comprises a central beam 14 fixing on the aircraft, and a movable rear portion 16 which is here a thrust reversal flap.
• the movable rear portion 16 of the nacelle 10 is driven in displacement by means of two actuators 18 arranged on either side of the beam 1 4, of which only one is detailed by the following and shown in FIG. 2.
• the actuator 18, shown in detail in Figures 3 to 7 extends from front to back along a longitudinal working axis B.
• the actuator 18 is essentially composed of a worm 20 which is rotatably mounted in a body 22 and which drives axially a main arm 24a through a main nut 26a.
• the body 22 which has a generally cylindrical shape along the working axis B, is fixed on the front portion 12 of the nacelle 10 by a main front attachment system 28a.
• the main front attachment system 28a has a U-shaped main front fitting 30a which is composed of a transverse attachment plate 32 and two longitudinal branches 34 which extend from the plate 32.
• the attachment plate 32 is fixed on the front part 12 of the nacelle
• the universal joint 36 has an annular shape formed by two vertical branches 38 which are pivotally mounted on the main front fitting 30a about a transverse axis, and two transverse branches 40 (only one of which is shown) which carry the body 22 of the actuator 18, so as to enable the body 22 to be swiveled.
• the body 22 delimits a central bore 42 along the axis B, which is equipped with a ball bearing 44.
• the worm 20 extends longitudinally along the working axis B from a rear section 45 to a front section 47 which is rotatably mounted in the ball bearing 44 about the axis. B.
• the front section 47 of the worm 20 has at its axial end a driven pinion 46 obliquely toothed which cooperates with a motor gear 48 obliquely toothed as well.
• the drive gear 48 is rotatably connected to a drive shaft 50 which extends perpendicular to the worm 20.
• the drive shaft 50 is rotated, for example by an electric motor (not shown), in a direction or in another opposite direction to drive the worm 20 in rotation in one direction or in another opposite direction.
• a driving device comprising this rotary motor which rotates the rotary motor shaft 50 which is mechanically coupled to the worm gear 20 via the pinions 46, 48 to rotate the screw in end 20
• another type of drive device for example with a shaft motor parallel to the worm 20, and in particular in the alignment of the worm 20.
• the main actuating arm 24a is doubled by a secondary actuating arm 24b which is arranged symmetrically along a transverse plane P passing through the working axis B.
• the main actuating arm 24a and the secondary actuating arm 24b each extend axially from a rear section adapted to be connected to the movable rear portion 16 of the nacelle 10, to a front section secured to the nut. principal 26a.
• the main nut 26a is screwed onto the worm 20 so as to slide the main actuating arm 24a and the secondary actuating arm 24b along the working axis B, between a front position in which the arms 24a, 24b are retracted, and a rear position in which the arms 24a, 24b are deployed.
• the actuator 18 comprises a secondary nut 26b which is screwed onto the worm 20, in the vicinity of the main nut 26a, and which is secured to the secondary actuating arm 24b.
• the secondary nut 26b makes it possible to drive the secondary actuating arm 24b in displacement to overcome a failure of the main nut 26a, such as a break, for example.
• Balls are interposed between the threads of the worm 20 and those of the main nut 26a and the secondary nut 26b, so as to reduce friction.
• the main actuating arm 24a and the secondary actuating arm 24b form a first half-be and a second complementary half-tube respectively, which extend along the working axis B.
• Each half-tube comprises a pair of radial fins 54a, 54b respectively which extend axially and which cooperate with one another to secure the main actuating arm 24a and the secondary actuating arm 24b to each other, for example by means of a series of screws (not shown), to form an axial tube in which the worm 20 is arranged.
• main actuating arm 24a and the secondary actuating arm 24b can form a first tube and a second tube respectively (not shown) which are arranged one in the other coaxially along the B axis of work.
• main actuating arm 24a and the secondary actuating arm 24b are connected to the movable rear portion 16 of the nacelle 10 by a main rear attachment system 56a and a secondary rear attachment means 56b.
• the main rear attachment system 56a has a main leg 58a which is formed by a first portion 60a secured to the main actuating arm 24a and a second portion 60b secured to the secondary actuating arm 24b.
• the main leg 58a delimits a hole 62 adapted for fixing a main rear fitting 64a which is intended to be connected to the movable rear part 16 of the nacelle 10 via a ball joint and a shaft, not shown. .
• the secondary fastening system 56b has a secondary lug 58b which is formed by a first portion 66a secured to the main actuating arm 24a and a second portion 66b secured to the secondary actuating arm 24b.
• the secondary leg 58b defines an oblong hole 68 designed for attaching a secondary rear fitting 64b intended to be connected to the movable rear portion 16 of the nacelle 10.
• the secondary rear attachment system 56b makes it possible to transmit a force between the actuator 1 8 and the movable rear part 1 6 of the nacelle 1 0 only in the event of failure of the main rear attachment system 56b, and not in normal running .
• the secondary rear fitting 64b of the secondary rear attachment system 56b is connected to the movable rear portion 16 of the nacelle 10 with axial play.
• the actuator 18 comprises a reinforcing rod 70 which extends axially along the working axis B, and which comprises a front section 72 passing through the body 22 of the actuator 18 and a rear section 74 threaded into a bore 76 of the worm 20 to retain the screw axially in case of breakage of the worm 20.
• the rear free end of the rod 70 delimits a first shoulder 78 which blocks the endless screw 20 in axial translation towards the rear, and the front free end of the rod 70 del mimics a second shoulder 80 which blocks the worm 20 in axial translation backwards, with an axial play allowing not to spend effort by this path in normal operation.
• the actuator 18 comprises a secondary front attachment system 28b which is designed to connect the front portion 12 of the nacelle 10 to the actuator 18, and to overcome a Failure of main front attachment system 28a.
• the secondary front attachment system 28b comprises a U-shaped front half fitting 30b which is composed of two longitudinal branches 82 and a front transverse plate 84.
• the two branches 82 are fixed on the front portion 12 of the nacelle 10, for example by screws (not shown), and the front plate 84 is interposed axially between the body 22 and the second shoulder 80 of the rod 70 to allow the passage of force between the front portion 12 of the nacelle 10 and the actuator 18.
• the front plate 84 of the secondary front fastening system 28b delimits a notch 86 open vertically, to allow disassembly and disassembly of the a n d e r e d e r 8 s e n d e r a n d e r a n d e r a n d 30b.
• the second shoulder 80 of the rod 70 forms a radial disk which bears axially backwards against the two branches 82 of the secondary front attachment system 28b.
• This feature allows disassembly and assembly of the actuator 18 without disassembling the front front bracket 30b, introducing the cylinder from the front, as shown by the arrow in Figure 7.
• the actuator 1 8 allows to "double" the main effort path that is borrowed during the "normal” operation of the actuator 1 8, to ensure the transmission of a traction force between the part before 12 fixed and the rear part 16 mobile of the nacelle 10.
• a traction force can be successively transmitted by a secondary force path of the second fastening system 28b, the reinforcing rod 70, the second nut is 26b, the secondary arm 24b and the secondary rear attachment system 56b.
• the secondary force path is used for the passage of a force only in case of breakage or failure of a part of the main effort path.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=48225031

Family Applications (1)

Country Status (4)

Families Citing this family (4)

Family Cites Families (6)

• 2013
  • 2013-02-25 FR FR1351612A patent/FR3002593B1/fr not_active Expired - Fee Related
• 2014
  • 2014-02-25 EP EP14711830.1A patent/EP2959147A1/de not_active Withdrawn
  • 2014-02-25 WO PCT/FR2014/050403 patent/WO2014128427A1/fr active Application Filing
• 2015
  • 2015-08-19 US US14/830,258 patent/US20150354500A1/en not_active Abandoned

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events