Patent ID: 12258925

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The figures comprise a relative reference frame X1, X2and X3respectively defining longitudinal (or axial), vertical and lateral directions orthogonal to each other.

FIGS.1and2show a propulsion unit1having a longitudinal central axis A1.

Next, the terms “upstream”, “downstream”, “front” and “rear” are defined with respect to a direction S1of gas flow through the propulsion unit1along the longitudinal central axis A1.

The propulsion unit1comprises a turbine engine2(visible inFIG.1), a nacelle3and a mast4(visible inFIG.2) allowing connecting the propulsion unit1to a wing of an aircraft (not represented).

In the example ofFIG.1, the turbine engine2is a turbofan engine comprising, from upstream to downstream, a fan5, a low-pressure compressor6, a high-pressure compressor7, a combustion chamber8, a high-pressure turbine9and a low-pressure turbine10. The compressors6and7, the combustion chamber8and the turbines9and10form a gas generator.

The turbojet engine2comprises a fan casing11connected to the gas generator by structural arms12.

The nacelle3comprises an upstream section15forming an air inlet, a middle section16which includes fan cowls enveloping the fan casing11and a downstream section17forming downstream of the propulsion unit1an outlet for discharging the gases generated by the turbojet engine2.

In a manner known per se, during operation of the turbojet engine2, an air flow20enters the propulsion unit1through the air inlet15, passes through the fan5and then splits into a central primary flow20M and a secondary flow20N. The primary flow20M flows in a primary gas circulation duct21M within the gas generator. In turn, the secondary flow20N flows in a secondary duct21N surrounding the gas generator and delimited radially outwards by the fan casing11and by the downstream section17of the nacelle3.

FIGS.3and4show the downstream section17of the nacelle3in more details.

Referring toFIG.4, the downstream section17comprises two half-assemblies25A and25B with a semi-cylindrical shape and symmetrical relative to each other relative to a longitudinal midplane P1passing through the longitudinal central axis A1and parallel to the vertical direction X2. Thus, the half-assemblies25A and25B extend laterally on either side of the plane P1and in particular on either side of the mast4.

In the following description and in some figures, references are used allowing distinguishing between elements located on one side of the plane P1and symmetrical elements located on the other side of this plane. This distinction is made by adding to these references the suffix “A” for the elements located on one side of the plane P1and the suffix “B” for those located on the other side. In general, all symmetrical elements are not represented in all figures. Furthermore, when a portion of the propulsion unit1has two half-portions symmetrical relative to the plane P1, the following description details in most cases only one of these half-portions. Unless stated otherwise, this description applies by analogy to the other corresponding half-portion.

In particular, the half-assembly25A is described hereinafter with reference toFIG.3. Hence, the following description relating to the half-assembly25A applies by analogy to the half-assembly25B.

The half-assembly25A comprises two portions which are movable relative to each other. One of these portions forms a structure30A herein called “fixed structure” which, in the flight configuration, remains in the same position with respect to the mast4. The other portion of the half-assembly25A forms a cowl31A that is movable relative to the fixed structure30A (cf. further below).

The fixed structure30A comprises on the one hand an inner fairing33A delimiting radially inwards a circumferential sector of a longitudinal portion of the secondary duct21N.

The inner fairing33A, commonly called “inner fixed structure”, comprises, vertically from bottom to top inFIG.3, a lower junction wall34A also called “six-o'clock” “island” or “bifurcation”, a semi-annular shaped central wall35A and an upper junction wall36A also called “twelve-o'clock” “island” or “bifurcation”.

Besides, the fixed structure30A comprises a lower beam37A secured to a radial end of the lower junction wall34A and an upper beam38A secured to a radial end of the upper junction wall36A.

The upper beam38A comprises a first connecting element41A allowing connecting the half-assembly25A to the propulsion unit1.

In this example, the first connecting element41A comprises eyelets configured to cooperate with shafts (not represented) connected to a beam (not represented) secured to the mast4so as to enable a movement of the half-assembly25A in rotation around an axis of rotation A2A passing through a centre of the eyelets41A.

Thus, the first connecting element41A allows moving the half-assembly25A between said flight configuration, illustrated inFIG.4, and a maintenance configuration illustrated inFIG.5.

In this example, the axis of rotation A2A is substantially parallel to the longitudinal central axis A1. In general, the axes A1and A2A can form an angle comprised between 0° and 3°

As regards the movable cowl31A, the latter extends radially outwards from the central wall35A of the fixed structure30A and has a semi-annular shape too.

Thus, the central wall35A of the fixed structure30A and the movable cowl31A define radially therebetween said circumferential sector of the longitudinal portion of the secondary duct21N, this sector extending circumferentially around the longitudinal central axis A1between the lower junction wall34A and the upper junction wall36A of the fairing33A.

In this example, the fixed structure30A comprises a wall45A connected to the central wall35A and extending behind the latter so as to form a half-portion of an exhaust nozzle46visible inFIG.4.

In a manner known per se, the movable cowl31A is connected to the lower beam37A and to the upper beam38A of the fixed structure30A according to a sliding connection.

In this example, this connection is made by slides (not represented) secured to the lower37A and upper38A beams and by rails (not represented) secured to the movable cowl31A which cooperate with these slides.

FIG.10schematically illustrates the sliding connection39A between the movable cowl31A and the lower beam37A.

Such a sliding connection enables the movable cowl31A to be moved, for example using cylinders (not represented), relative to the fixed structure30A in translation according to the longitudinal central axis A1between an extended position, illustrated inFIGS.1,2and4, and a retracted position, illustrated inFIG.6.

In the extended position, a front end of the movable cowl31A is flush with a rear end of the fan cowl located on the same side of the plane P1as the movable cowl31A, so as to reduce the discontinuity between these cowls and thus reduce aerodynamic disturbances outside the nacelle3.

In the retracted position, the front end of the movable cowl31A and the rear end of the corresponding fan cowl of the middle section16are separated from each other by a distance Y1defining a space forming a radial opening (cf.FIG.6).

In this example, the nacelle3comprises cascades50A and50B extending respectively on one side and on the other of the plane P1.

The cascades50A extend through the aforementioned radial opening when the movable cowl31A is in the retracted position.

Moreover, referring toFIG.3, the half-assembly25A comprises flaps52A and connecting rods54A.

In a manner known per se, each of the flaps52A is hinged on the movable cowl31A and each of the connecting rods54A is connected on the one hand to a respective one of the flaps52A and on the other hand to the central wall35A of the fairing33A of the fixed structure30A so that, when the movable cowl31A switches from the extended position to the retracted position, the flaps52A deploy radially in the secondary duct21N so as to seal this duct21N.

Thus, the downstream section17of the nacelle3forms a thrust reverser.

When the movable cowl31A and31B of each of the half-assemblies25A and25B is in the extended position, also called “direct thrust position”, the secondary flow20N is routed to the rear of the propulsion unit1throughout the longitudinal portion of the secondary duct21N defined by the downstream section17. In this direct thrust configuration, the flaps52A of the half-assembly25A as well as the flaps (not represented) of the half-assembly25B are folded down against the inner wall of the corresponding movable cowl31A or31B. Thus, the secondary flow20N contributes to thrust generation.

When the movable cowl31A and31B of each of the half-assemblies25A and25B is in the retracted position, also called “thrust reversal position”, the flaps52A of the half-assembly25A as well as the flaps of the half-assembly25B seal the secondary duct21N so as to redirect the secondary flow20N towards said radial opening. Thus, the secondary flow20N passes through the cascades50A and50B while being diverted thereby towards the front of the propulsion unit1. Thus, the secondary flow20N allows generating a counter-thrust. Referring toFIG.7, the nacelle3comprises a connecting beam60extending along a longitudinal axis A3.

In this example, the axis A3is parallel to the longitudinal central axis A1of the propulsion unit1and passes through the longitudinal midplane P1.

With reference to a longitudinal midplane P2perpendicular to the plane P1and passing through the longitudinal central axis A1, the connecting beam60is located on one side of the plane P2, opposite the mast4which is located on the other side of this plane P2.

In other words, the connecting beam60is located at six o'clock whereas the mast4is located at twelve o'clock.

The connecting beam60is mounted on the middle section16so as to be secured to the fan casing11.

The connecting beam60comprises a downstream portion extending cantilevered with respect to a rear end of the fan casing11.

In the example ofFIG.7, the middle section16comprises, on either side of the longitudinal midplane P1, inner fairings62A and62B having a shape similar to the inner fairing33A described hereinabove with reference toFIG.3.

For each of the inner fairings62A and62B,FIG.7shows a portion of this inner fairing comprising a central wall63A or63B.

The inner fairings62A and62B are connected to the connecting beam60by the lower junction walls64A and64B, respectively.

Of course, each of the inner fairings62A and62B comprises an upper junction wall (not represented) enabling them to be connected to a fixed portion (not represented) of the propulsion unit1.

Each of the inner fairings62A and62B carries a groove65A or65B configured to receive a portion of the inner fairing33A or33B of the half-assembly25A or25B in the flight configuration. The grooves65A and65B form an interface allowing ensuring aerodynamic continuity on the one hand between the inner fairings62A and33A and on the other hand between the inner fairing62B and the inner fairing (not represented) of the half-assembly25B.

In this example, the cascades50A and50B are movable in translation along the longitudinal central axis A1.

To this end, each of them is connected according to a sliding connection on the one hand at twelve o'clock to a fixed portion of the propulsion unit and on the other hand to the connecting beam60.

In the embodiment ofFIG.7, slides66A and66B are fastened on the lateral portions of the connecting beam60and the cascades50A and50B carry rails (not visible inFIG.7) which cooperate with the slides66A and66B.

InFIG.7, the cascades50A and50B are in an extended position.

In this example, the cascades50A and50B are secured respectively to the movable cowl31A of the half-assembly25A and to the movable cowl of the half-assembly25B, in translation along the longitudinal central axis A1so that, when these movable cowls are in the direct thrust position, the cascades50A and50B are in the extended position and when the movable cowls are in the thrust reversal position the cascades50A and50B are in the retracted position.

In this example, when the half-assemblies25A and25B are in the flight configuration, the movable cowls cooperate with the cascades50A and50B through a tenon-and-groove connection similar to the connection between the connecting member70and said second connecting element of the half-assemblies25A and25B.

In the extended position, the cascades50A and50B are at least partially accommodated in a space extending radially between the fan casing11and a respective fan cowl of the middle section16.

In the retracted position, the cascades50A and50B extend into the radial opening extending longitudinally between the movable cowls of the half-assemblies25A and25B and the fan cowls of the middle section16(cf. hereinabove andFIG.6).

More specifically, the invention relates to the cooperation of the half-assemblies25A and25B with the connecting beam60.

The portion of the connecting beam60visible inFIG.7has one end forming a connecting member70which cooperates with a second connecting element of the half-assemblies25A and25B when these are in the flight configuration.

Geometrically, the connecting member70extends:between two transverse planes perpendicular to the longitudinal central axis A1,between two longitudinal planes parallel to the longitudinal midplane P1and extending on either side of the longitudinal axis A3,between two longitudinal planes parallel to the longitudinal midplane P2and extending on either side of the longitudinal axis A3.

Referring toFIG.8, the connecting member70has two lateral vertices71A and71B, a lower base72and an upper base73configured so as to admit a longitudinal plane parallel to the plane P2which passes through the longitudinal axis A3and through the two lateral vertices71A and71B at the same time, and so that the plane P1passes through the lower base72and through the upper base73.

The connecting member70comprises four branches74respectively connecting the upper base73and the lateral vertex71A to each other, the lateral vertex71A and the lower base72to each other, the lower base72and the lateral vertex71B to each other, and the lateral vertex71B and the upper base73to each other.

The branches74are oblique with respect to the longitudinal midplanes P1and P2.

The connecting member70is symmetrical relative to the plane P1.

On either side of the plane of symmetry P1, the connecting member70has a C-like shaped cross-section, the lower base72and the upper base73forming the free ends of the C.

The connecting member70comprises a groove75extending circumferentially around the axis A3.

In this example, the groove75is formed on the four branches74, on the lateral vertices71A and71B and on the lower base72and forms a unique continuous groove.

FIG.8shows the lower beams37A and37B of the half-assemblies25A and25B respectively, as well as the connecting beam60in an exploded view.

The beam37A ofFIG.8comprises one end forming said second connecting element80A of the half-assembly25A.

The second connecting element80A comprises a wall81A having a shape complementary to the half-portion of the connecting member70extending on the same side of the plane P1as the half-assembly25A. Hence, the wall81A also has a C-like shape.

The wall81A forms a half-cavity configured to envelop this half-portion of the connecting member70when the half-assembly25A is in the flight configuration, as illustrated inFIGS.9and10.

The second connecting element80A comprises a tenon82A extending in this example over the wall81A, within the half-cavity formed by this wall81A.

The tenon82A is configured to fit into the groove75, more specifically into the half-portion of the groove75extending on the same side of the plane P1as the half-assembly25A, when the half-assembly25A is moved from the maintenance configuration up to the flight configuration so as to position the fixed structure30A of the half-assembly25A with respect to the connecting member70and therefore with respect to the connecting beam60.

In this example, the groove75has a trapezoidal shape. More specifically, it has a bottom surface and lateral surfaces which are oblique with respect to the bottom surface so that the width of the groove75is larger at the outer surface of the connecting member70onto which it opens than at the bottom surface.

The tenon82A has a complementary shape and has a trapezium-shaped section.

Such a geometry of the tenon82A and of the groove75allows increasing the accuracy of positioning as the half-assembly25A approaches the flight configuration while facilitating the penetration of the tenon82A into the groove75while taking into account in particular of clearances in the mechanism.

The previous description relating to the cooperation of the second connecting element80A of the half-assembly25A applies by analogy to the connecting element80B of the half-assembly25B.

It follows from the foregoing that, when the half-assemblies25A and25B are in the maintenance configuration, these are detached off the connecting member70and that, when the half-assemblies25A and25B are in the flight configuration, these are connected to each other via the connecting member70with which they cooperate so as to be properly positioned with respect to the beam60.

In this example, locking of the half-assemblies25A and25B in the flight configuration is ensured by two locks91and92.

Referring toFIGS.9and11, the locks91and92are mounted one behind the other downstream of the second connecting elements80A and80B, proximate to the connecting member70.

FIGS.12and13show the lock91respectively in a locking position and in an unlocking position.

In this example, the lock91comprises a hook95, an actuating handle96and connecting rods97connecting the hook95and the handle96to each other.

The lock91is configured so that the handle96is flush with an outer surface of the lower beams37A and37B of the half-assemblies25A and25B when these are in the flight configuration and the lock91is in the locking position. This allows manually actuating the handle96while preventing it from projecting with respect to the outer surface of the lower beams37A and37B.

In this example, the lock91is mounted on the lower beam37B of the half-assembly25B. When the lock91is in the locking position, the hook95cooperates with a hooking element98secured to the lower beam37A of the half-assembly25A so as to exert on the lower beam37A a tensile force tending to bring it closer to the lower beam37B according to the lateral direction X3.

The movement of the lock91between the locking and unlocking positions is ensured by the connecting rods97and by a guide element94such as a cam secured to the lower beam37B.

The lock91is called “inner lock” because the hook95is offset radially inwards with respect to the handle96.

Indeed, the hook95and the hooking element98extend radially between the longitudinal central axis A1of the propulsion unit1and the longitudinal axis A3of the beam60(cf.FIG.11).

In other words, in the locking position, the active portion of the inner lock91extends radially inwards with respect to the longitudinal axis A3, whereas the actuating portion of the inner lock91extends radially outwards with respect to the longitudinal axis A3.

FIGS.14and15illustrate another embodiment wherein the inner lock91differs from that ofFIGS.12and13in that it comprises an additional connecting rod97X allowing dispensing with the guide element94.

The lock92, not represented in details, is a conventional lock which operates according to the same general principle as the inner lock91.

Nonetheless, the active portion of the lock92is not offset radially inwards with respect to the longitudinal axis A3.

Consequently, in contrast with the inner lock91, the lock92forms an “outer lock” to the extent that it extends and acts on a portion of the beams37A and37B located radially outwards with respect to the longitudinal axis A3.

Positioning and/or holding of the beams37A and37B in position with respect to the connecting member70and/or tightness can be improved by interposing one or more seal(s) between these different elements.

In the example ofFIG.11, a first seal77is accommodated in a groove (not represented) made in the connecting beam60, upstream of the groove75and a second seal78is accommodated in the groove75. The nacelle may comprise a sealing system formed by a series of seals including for example the seals77and78and/or other seals.

Referring toFIGS.7,8and10, the connecting beam60provides for a hollow inner space forming a passage for auxiliaries100of the turbojet engine2.

A portion of this inner space is delimited by two partitions102extending in line with the upper base73of the connecting member70(cf.FIG.8).

In the example ofFIG.4, the nacelle3comprises a box110accommodating the connecting beam60and the lower beams37A and37B of the half-assemblies25A and25B. Of course, the previous description is not restrictive. For example, the groove75may be discontinuous and/or have a rectangular geometry or any other shape. As another example, the second connecting element80A and/or80B may comprise instead of or complementarily with the tenon82A or82B one or more groove(s) (not represented) cooperating with one or more tenon(s) (not represented) secured to the connecting member70.