Device and method for assembling a fixed thrust reverser structure of an aircraft propulsion assembly

An assembly device includes a framework resting on a planar support, a support element mounted movably in rotation relative to the framework, an immobilizing device, and a positioning assembly mounted in rotation on the support element. A front frame of the fixed structure is positioned on the positioning assembly, and the immobilizing device is arranged to immobilize the front frame on the positioning assembly. In particular, the assembly device allows, in the immobilizing position on the positioning assembly, for the front frame to extend transversely to the planar support.

FIELD

The present disclosure relates to a device for assembling a fixed thrust reverser structure of an aircraft propulsion assembly, and to a method for assembling such a fixed structure.

BACKGROUND

An aircraft is driven by several propulsion assemblies each suspended from a fixed structure of the aircraft, for example under a wing or on the fuselage of the aircraft, via a suspension pylon.

Each propulsion assembly comprises, in a well-known manner, on the one hand a turbojet engine equipped with a fan and an engine, and on the other hand a nacelle covering the turbojet engine and housing a thrust reverser.

A nacelle generally presents a tubular structure comprising an air inlet upstream of the turbojet engine, a median section intended to surround the fan of the turbojet engine, a downstream section housing the thrust reverser and intended to surround a combustion chamber and the turbines of the turbojet engine, and is generally ended by an ejection nozzle, the outlet of which is located downstream of the turbojet engine.

A thrust reverser is adapted, during landing of the aircraft, to improve the braking capacity thereof by redirecting forward at least part of the thrust generated by the corresponding turbojet engine. A thrust reverser generally comprises an outer fixed structure called OFS, an inner fixed structure called IFS which surrounds the engine behind the fan, and a movable structure comprising for example movable cowls. The outer and inner fixed structures define a path intended for the circulation and the exhaust of a cold air flow.

The outer fixed thrust reverser structure comprises, in a well-known manner, in particular a peripheral front frame intended to be mounted on a fan casing of the corresponding turbojet engine, a peripheral rear frame, and a plurality of flow cascades secured between the front and rear frames and extending substantially parallel to the longitudinal geometrical axis of the thrust reverser. The front and rear frames are disposed transversely with respect to the longitudinal geometrical axis of the thrust reverser. The outer fixed structure further comprises a significant number of equipment mounted on the front frame and on either side of the latter, such as cylinders for actuating the movable thrust reverser structure, tubes for guiding the actuating cylinders, brackets for mounting the actuating cylinders, brackets for mounting actuating rods intended to actuate blocking flaps belonging to the movable thrust reverser structure.

Recently, O-shaped thrust reversers (O-Duct) have been developed. The outer fixed structure of a thrust reverser with O-shaped structure extends substantially from one side of the corresponding suspension pylon to the other side of the latter. In order to carry out the assembling of such an outer fixed structure, it is well-known to dispose the front frame substantially horizontally on a handling table, and to assemble the various equipment of the outer fixed structure on the latter.

Such an assembling method induces a significant number of reversals of the front frame in order to gain access to either side of the front frame for the assembling of the various equipment, which require the disposition of suitable handling tools and complicates the assembling of the thrust reverser. In addition, such an assembling method requires the disposition of bridges and scaffolds to access the center of the front frame, which generates significant congestion of the assembling area of such a thrust reverser. Moreover, this assembling method leads to inappropriate postures for the operators who are carrying out the assembling of such thrust reversers. This results in a difficult and costly assembling of such O-shaped thrust reversers.

This results in multiplication of the manufacturing cost of such a thrust reverser. In addition, the assembling is difficult for the operators due to the positions.

SUMMARY

The present disclosure relates to a device for assembling a fixed thrust reverser structure of an aircraft propulsion assembly, the fixed structure comprising a front frame intended to be mounted on a fan casing of a turbojet engine of the propulsion assembly, the assembling device comprising:

a framework intended to rest on a planar support,

a support element movably mounted in rotation with respect to the framework about an axis of rotation,

a positioning assembly mounted integral in rotation on the support element and on which a front frame is intended to be positioned, and

immobilization means arranged to immobilize the front frame on the positioning assembly, the assembling device being configured in such a way that, in the position of immobilization on the positioning assembly, the front frame extends transversely to the planar support, and the positioning assembly and the immobilization means are arranged in such a way that, in the immobilization position on the positioning assembly, the front frame extends transversely to the axis of rotation of the support element.

Such a configuration of the assembling device according to the present disclosure allows an operator to easily access either side of the front frame in the immobilization position of the positioning assembly, and thus to easily assemble on the front frame, and on either side of the latter, the various equipment forming the fixed thrust reverser structure. This assembly is much easier if the operator can position the front frame in the most appropriate position to perform the assembling of each piece of equipment, and this is simply done by rotating the support element about its axis of rotation.

Such a configuration of the assembling device according to the present disclosure also allows reducing the congestion of the assembling area of the fixed structure.

According to one form of the present disclosure, the assembling device is configured in such a way that, in the immobilization position on the positioning assembly, the front frame extends substantially perpendicularly to the planar support.

According to another form of the present disclosure, the positioning assembly is removably mounted on the support element.

In other form of the present disclosure, the axis of rotation of the support element is substantially horizontal under conditions of use of the assembling device. Preferably, the angle of inclination of the axis of rotation of the support element with respect to the horizontal is comprised between −20 and +20°, preferably between −10 and +10° and advantageously between −5 and +5°.

Advantageously, the positioning assembly and the immobilization means are arranged in such a way that, in the immobilization position on the positioning assembly, the front frame extends substantially perpendicularly to the axis of rotation of the support element. In another form, the angle of inclination of the axis of rotation of the support element with respect to the front frame in the immobilization position is comprised between 70 and 110°, alternately between 80 and 100°, and advantageously between 85 and 95°.

As one form according to the present disclosure, the assembling device is arranged in such a way that, in the immobilization position on the positioning assembly, the front frame is substantially centered with respect to the axis of rotation of the support element.

According to another form of the present disclosure, the support element includes a longitudinal axis substantially centered on the axis of rotation of the support element. For example, the support element includes a substantially cylindrical outer shroud with an axis substantially centered on the axis of rotation of the support element.

According to another form of the present disclosure, the positioning assembly comprises at least one positioning element presenting a peripheral mounting wall on which the front frame is intended to be mounted. In one form, the front frame is intended to bear against the peripheral mounting wall.

The peripheral mounting wall can be delimited by a substantially cylindrical surface portion. The peripheral mounting wall can be substantially centered on the axis of rotation of the support element.

In still other form, the positioning assembly comprises a connecting reinforcement mounted on the support element, the at least one positioning element being mounted on the connecting reinforcement.

According to one form of the present disclosure, the positioning assembly comprises two positioning elements.

According to another form of the present disclosure, each positioning element extends in a circular arc.

In an advantageous manner, the peripheral mounting wall comprises a plurality of mounting orifices arranged to cooperate with the immobilization means. Advantageously, the mounting orifices arranged on the peripheral mounting wall are oblong and preferably extend substantially in parallel with the axis of rotation of the support element.

According to one form of the present disclosure, the immobilization means include at least one immobilization member, such as an immobilization pin, movably mounted between an immobilization position of the front frame in which the at least one immobilization member is arranged to extend through an opening arranged in the front frame and one of the mounting orifices belonging to the peripheral mounting wall, and a release position of the front frame.

According to another form of the present disclosure, the immobilization means include at least one clamping member movably mounted between a clamping position of the front frame in which the at least one clamping member is arranged to exert a pressure against the front frame so as to press the front frame against the peripheral mounting wall, and a release position of the front frame.

In an advantageous manner, the immobilization means include a plurality of immobilization elements angularly shifted from one another with respect to the axis of rotation of the support element. Each immobilization element includes for example at least one clamping member and/or at least one immobilization member.

According to one form of the present disclosure, each immobilization element includes an actuating lever connected to the at least one corresponding clamping member and/or the at least one corresponding immobilization member, the actuating lever being pivotally mounted between a first position in which the at least one corresponding clamping member and/or the at least one corresponding immobilization member is in its release position, and a second position in which the at least one corresponding clamping member and/or the at least one corresponding immobilization member are in their clamping and immobilization position, the actuating lever being arranged in such a way that a displacement of the actuating lever between its first and second positions causes a displacement of the at least one corresponding clamping member and/or the at least one corresponding immobilization member between their release position and their clamping and immobilization position.

Each immobilization element is preferably mounted on the positioning assembly, for example on the at least one positioning element.

According to another form of the present disclosure, the assembling device comprises holding means mounted on the support element and arranged to hold the front frame on the support element. The holding means are, for example, removably mounted on the support element. According to one form of the present disclosure, the holding means include a plurality of holding arms angularly shifted from one another with respect to the axis of rotation of the support element. Advantageously, each holding arm comprises a connecting portion provided with a securing eyelet intended for the passage of a securing pin. In one form, each arm extends substantially radially with respect to the longitudinal axis of the support element. The arms are mounted for example on the outer shroud of the support element.

According to another form of the present disclosure, the assembling device comprises rotatably driving means arranged to drive in rotation the support assembly about its axis of rotation. Advantageously, the rotatably driving means include a drive shaft with a longitudinal axis substantially coincident with the axis of rotation of the support assembly, and a steering wheel coupled to the drive shaft and arranged to drive in rotation the drive shaft about its longitudinal axis.

According to one form of the present disclosure, the immobilization means include securing means arranged to secure the ends of the front frame of the positioning assembly.

The securing means include for example:a first and second securing portions mounted on the positioning assembly and each provided with a securing orifice, anda first and second securing pins intended to extend respectively on the one hand through an opening arranged in a support portion of the front frame on which flow cascades are intended to be mounted, and on the other hand through the securing orifice belonging to one of the first and second securing portions.

According to another form of the present disclosure, the assembly device includes blocking means mounted on the positioning assembly and arranged to block in position two maintenance rails with respect to the front frame in view of their mounting on the front frame, said maintenance rails being intended to be slidably mounted on the suspension pylon intended to receive the propulsion assembly.

The present disclosure further relates to a method for assembling a fixed thrust reverser structure of an aircraft propulsion assembly, comprising the steps consisting of:providing an assembling device according to the present disclosure,positioning a front frame of the fixed structure on the positioning assembly, immobilizing the front frame on the positioning assembly using immobilization means, andassembling various pieces of equipment on the front frame so as to form the fixed structure, the assembling step comprising at least one step consisting of driving in rotation the support element about its axis of rotation.

According to one implementation mode of the present disclosure, the positioning step consists of centering the front frame on the axis of rotation of the support element.

According to another implementation mode of the present disclosure, the front frame extends substantially in a circular arc. According to other implementation mode of the present disclosure, the front frame extends over an angle comprised between 270 and 340°. The front frame presents for example a substantially annular shape.

According to an implementation mode of the present disclosure, the assembling step comprises at least one step consisting of securing a rear frame of the fixed structure on the front frame via spacing parts secured on the one hand on the front frame and on the other hand on the rear frame.

According to an implementation mode of the present disclosure, the assembling step comprises the steps consisting of:holding the front frame on the support element by means of the holding means,releasing the front frame from the positioning assembly,dismounting the positioning assembly of the support element, andassembling a connecting part on the front frame, said connecting part being intended to be mounted on the fan casing of the turbojet engine of the propulsion assembly.

According to an implementation mode, the connecting part has a substantially J-shaped section.

According to another implementation, the method comprises a step prior to the positioning step of the front frame consisting of assembling a connecting part on the front frame, said connecting part being intended to be mounted on the fan casing of the turbojet engine of the propulsion assembly.

According to an implementation mode, the assembling step comprises a step of displacing the assembling device successively along different assembling stations.

According to another implementation mode, the assembling method comprises a step consisting of displacing the assembling device up to a station for mounting the fixed structure on the turbojet engine of a propulsion assembly.

DETAILED DESCRIPTION

FIGS. 1 and 2represent an assembling device2in an O-shaped fixed thrust reverser structure of an aircraft propulsion assembly, and more particularly an outer fixed structure called OFS.

The assembling device2comprises a framework3and a platform4resting on the framework3. The framework3comprising in particular a substantially vertical upright5and a beam6integral with the upright5and substantially horizontal. The framework3is particularly equipped with bearing pads7intended to rest on the ground.

The assembling device2also comprises a drive shaft8with a substantially horizontal longitudinal axis A extending through the beam6, and a steering wheel9coupled to the drive shaft8, for example via a reducer11. The steering wheel9is arranged to drive in rotation the drive shaft8about its longitudinal axis.

The assembling device2also comprises a support drum12integral in rotation with the drive shaft8. The support drum12includes a substantially cylindrical shroud13with an axis centered on the longitudinal axis A of the drive shaft8. The support drum12includes a plurality of securing plates14secured to the outer surface of the shroud13and extending substantially radially with respect to the shroud13. Each securing plate14is advantageously provided with at least one securing orifice15.

The assembling device2further comprises a connecting reinforcement16extending substantially perpendicularly to the longitudinal axis A of the drive shaft8, and in particular substantially vertically. The connecting reinforcement16is removably mounted on the support drum12. The connecting reinforcement16alternately includes a plurality of securing plates17each provided with at least one securing orifice18. Each securing plate17is arranged to be secured by screwing or bolting to one of the securing plates14of the support drum12.

The assembling device2further comprises two positioning elements19integral with the connecting reinforcement16, and symmetrically disposed with respect to the support drum12. The connecting reinforcement16and the two positioning elements19advantageously form a removable positioning assembly.

The two positioning elements19extend substantially vertically. Each positioning element19presents a substantially circular arc shape, and includes a peripheral mounting wall21on which a front frame of the fixed thrust reverser structure is intended to bear directly or indirectly.

According to the form represented in the drawings, the peripheral mounting wall21of each positioning element19is delimited by a portion of a cylindrical surface centered on the longitudinal axis A of the drive shaft8. The peripheral mounting wall21of each positioning element19comprises a plurality of mounting orifices22distributed longitudinally along the peripheral mounting wall21. Each mounting orifice22may for example be oblong and extend substantially in parallel with the longitudinal axis A of the drive shaft8.

The assembling device2also comprises immobilization means arranged to immobilize the front frame on the positioning elements19and the positioning reinforcement16.

According to the form represented in the drawings, the immobilization means include a plurality of immobilization elements23mounted on the positioning elements19, and angularly shifted from one another with respect the longitudinal axis A of the drive shaft8. Each immobilization element23includes an immobilization member24, such as an immobilization pin, movably mounted between an immobilization position of the front frame in which the immobilization element24is arranged to extend through an opening arranged in the front frame and one of the mounting orifices22arranged on the peripheral mounting wall21of the corresponding positioning element19, and a release position of the front frame in which the immobilization element24is located distant from the corresponding positioning element19.

Each immobilization element23also includes two clamping members25disposed on either side of the corresponding immobilization member24. The two clamping members25of each immobilization element23are movably mounted between a clamping position of the front frame in which the clamping members25are arranged to exert a pressure against the front frame so as to press the front frame against the peripheral mounting wall21of the corresponding positioning element19, and a release position of the front frame in which the clamping members25are located distant from the corresponding positioning element19.

Each immobilization element23also includes an actuating lever26connected to the corresponding immobilization and clamping members24,25. The actuating lever26of each immobilization element23is pivotally mounted between a first position in which the corresponding immobilization and clamping members24,25are in their release position, and a second position in which the corresponding immobilization and clamping members24,25are in their immobilization and clamping position. The actuating lever26is advantageously arranged in such a way that the displacement of the actuating lever26between its first and second positions causes a displacement of the corresponding immobilization and clamping members24,25between their release position and their immobilization and clamping position.

As shown more particularly inFIG. 5, each immobilization element23advantageously forms a toggle clamp. Therefore, each immobilization element23comprises a chassis27mounted on the corresponding positioning element19, the corresponding actuating lever26being pivotally mounted on the chassis27about a pivot axis. Each immobilization element23also comprises a support member28pivotally mounted on the chassis27about a pivot axis parallel to the pivot axis of the corresponding actuating lever26, the corresponding immobilization and clamping members24,25being mounted on the support member28. Each immobilization element23further comprises at least one link29the ends of which are hingedly mounted respectively on the support member28and the corresponding actuating lever26.

The immobilization means also include securing means arranged to secure the ends of the front frame on the connecting reinforcement16. As shown more particularly inFIG. 4, the securing means advantageously include two securing parts31mounted on the connecting reinforcement16, and two securing pins32intended to extend respectively through, on the one hand, an opening arranged in a support portion of the front frame on which flow cascades are intended to be mounted, and on the other hand, a securing orifice (not visible in the drawings) arranged in one of the securing parts31.

The assembling device2further comprises two holding means removably mounted on the support drum12, and arranged to hold the front frame on the support drum12.

According to the form shown in the drawings, the holding means include a plurality of holding arms33angularly shifted from one another with respect the longitudinal axis A of the drive shaft8. Each holding arm33comprises a securing portion33amounted on the outer surface of the shroud13of the support drum12, and extending substantially radially from the shroud13. Each holding arm33comprises furthermore a connecting portion33bintegral with the corresponding securing portion33a, and extending substantially parallel to the longitudinal axis A of the drive shaft8in the direction of the positioning elements19. Each holding arm33further comprises a connecting portion33chingedly mounted on the corresponding connecting portion33babout a hinge axis substantially perpendicular to the longitudinal axis A of the drive shaft8, in order to facilitate the securing of said holding arm33on the front frame.

The connecting portion33cof each holding arm33alternately cooperates with a securing clevis mounted on the front frame. Therefore, the connecting portion33cis advantageously provided with a securing eyelet intended for the passage of a securing pin34able to cooperate also with the corresponding securing clevis.

According to one form of the present disclosure, the assembling device2further includes blocking means mounted on the connecting reinforcement16and arranged to block in position two maintenance rails with respect to the front frame in view of their mounting on the latter. Such maintenance rails are intended to be slidably mounted on a suspension pylon of an aircraft. As shown more particularly inFIG. 7, the blocking means advantageously include two clamping elements35each provided with a reception housing36intended to receive a ledge of the corresponding maintenance rail, and a pressure member37opening into the corresponding reception housing36and arranged to exert pressure against the corresponding ledge of the maintenance rail.

A method for assembling a fixed structure40of a thrust reverser60of an aircraft propulsion assembly by means of the assembling device2according to the present disclosure will now be described.

The assembling method comprising the following steps:

positioning two half-frames41forming a front frame42of the fixed structure on the positioning elements19,

immobilizing each half-frame41on the connecting reinforcement16by introducing a securing pin32on the one hand in a securing orifice43arranged on a support wall44of said half-frame41, and on the other hand in a securing orifice arranged in the corresponding securing part31,

immobilizing each half-frame41on the corresponding positioning assembly19by means of the corresponding immobilization elements23, and this is done by displacing the actuating lever26of said immobilization elements23in their second position,

assembling the two half-frames41to one another via a fishplate45positioned at “6 o'clock”

assembling various equipment on the front frame42and on both sides thereof so as to form the fixed structure.

The step of assembling the various equipment comprises at least one step comprising driving in rotation the support drum12using the steering wheel9in order to position the front frame42in an appropriate position, so as to facilitate the assembling of the various equipment.

The step of assembling the various equipment comprises in particular the following steps:

securing brackets46on the front frame42(seeFIG. 8), said securing brackets46being intended for securing actuating rods adapted to actuate blocking flaps belonging to the movable structure70of the thrust reverser,

securing a rear frame47of the fixed structure on the front frame42by means of spacing parts48, each spacing part48having a first end secured on the front frame42and a second end secured on the rear frame47, each spacing part48having a length corresponding to the length of the flow cascades intended to equip the fixed structure,

securing guide tubes49on the front and rear frames42,47(seeFIG. 6), said guide tubes49being intended for guiding the various actuation cylinders of the movable structure of the thrust reverser,

securing maintenance rails51on the rear frame47(seeFIG. 7),

immobilizing the maintenance rails51with respect to the front frame42using clamping members35,

securing two mounting brackets52at the ends of the front frame42, that is to say, “12 o'clock”, each mounting bracket52being provided with a passage clearance53,

introducing at least one rod54through each passage port53

securing the ends of each rod54respectively on the mounting brackets52and the corresponding maintenance rail51using securing pins55.

According to an implementation mode of the assembling method, the step of assembling the various equipment comprises in particular the following steps:

mounting the holding arms33on the support drum12,

securing the holding arm33on the securing brackets46so as to hold the front frame42on the support drum12,

releasing the front frame42from each positioning element19and from the connecting reinforcement16

dismounting the connecting reinforcement16from the support drum12,

assembling a connecting part56, such as an annular flange, having a J-shaped section, also called a J-ring, on the front frame42(seeFIG. 11), said connecting part56being intended to be mounted on the fan casing of the turbojet engine of the propulsion assembly,

dismounting the spacing parts48,

securing the rest of the equipments forming the fixed structure on the front and rear frames42,47, such as in particular the flow cascades80.

According to an implementation mode, the assembling method comprises a step of displacing the assembling device2successively along various assembling stations, in order to carry out the assembling of the fixed thrust reverser structure.

According to another implementation mode, the assembling method comprises a step of displacing the assembling device2up to a mounting station of the fixed structure on the turbojet engine of a propulsion assembly.

According to another implementation of the assembling method, the connecting part56could be mounted on the front frame42prior to its positioning on the positioning elements19. According to this implementation of the method, the front frame42is mounted on the positioning elements19via said connecting part56. In such a case, each positioning element19includes a mounting portion19amounted on the connecting reinforcement16, and a positioning portion19bintegral with the mounting portion19band on which the connecting part56is intended to be mounted. According to such a form, each immobilization element23could include a clamping member58arranged to exert pressure against the connecting part56so as to press the connecting part56against the mounting portion19b.

As it goes without saying, the present disclosure is not limited to the sole form of this assembling device, described above by way of example, it encompasses on the contrary all the alternative forms. This is particularly how the assembling device could be used to assemble the fixed structure of a thrust reverser of the C-duct type.