Connecting device for providing a connection between annular elements of an aircraft propulsion unit with sealing elements, and corresponding turbomachine

Abstract

The invention relates to a connecting device (10) for an aircraft propulsion unit comprising a first element (11) of a cowl (9) and a second element (12) of a casing (7) centred on the longitudinal axis (X), the second element (12) comprising a groove (13) extending partially around the longitudinal axis and receiving a first sealing element (17), the first element being able to rotate with respect to the casing between a closed and an open position, and comprising a rib (20) at least partially compressing the first sealing element (17), radially, in the closed position. According to the invention, the connecting device comprises a second sealing element (22) which is disposed between the first sealing element and the first element in the closed position, the second sealing element being arranged to radially compress the first sealing element in the closed position and in a direction substantially parallel to the longitudinal axis.

Description

Description TITLE: CONNECTION DEVICE BETWEEN ANNULAR ELEMENTS OF AN AIRCRAFT PROPULSION UNIT WITH SEALING ELEMENTS AND CORRESPONDING TURBOMACHINE Technical field of the invention

[0001] The present invention relates to the field of propulsion assemblies comprising an aircraft turbomachine. The invention relates more specifically to a connecting device between a first element of a nacelle and a second annular element of a casing of the turbomachine enclosed by the nacelle. Technological background

[0002] An aircraft propulsion system generally comprises a turbomachine with a casing, centred on a longitudinal axis, surrounding at least the combustion chamber of the turbomachine and a nacelle which envelops the casing. The propulsion system comprises a suspension mast or pylon which allows the turbomachine to be suspended or attached to the structure of the aircraft.

[0003] The nacelle may be equipped with thrust reversers which comprise cowls in the form of half-shells or an annular cowl over 360° and which are movable relative to the casing and the rest of the nacelle. Each cowl is articulated by one end on the attachment pylon using one or more hinges or one or more slides whose axis extends along the longitudinal axis. The free end of a cowl is locked to a free end of another cowl and each cowl is connected to the casing in order to transfer the aerodynamic forces, in particular axial forces, which each cowl undergoes to the casing.

[0004] The casing comprises an annular groove having a V or U-shaped section, centered on the longitudinal axis and at the bottom of which is arranged an O-ring. The nacelle is equipped with a rib or protrusion having a shape complementary to that of the groove and intended to engage in the groove when locking the or each cover on the casing. The rib compresses the O-ring which ensures the airtightness of the assembly when the or each cover is closed and locked. The shape of the rib also makes it possible to guide the closing of the or each cover. The connection between the groove and the rib is arranged near the hinge provided at the level of the suspension mast. Such an example of an assembly propulsive with a connection between the groove and the rib compressing an O-ring is described in patent document FR-A1-2756323 also published under number US6032901.

[0005] However, since the nacelle and casing are made up of different parts or covers, this can break the seal at different points and affect the aerodynamics of the propulsion unit. In particular, airflow leaks and fire risks can occur at the connections between the casing and the nacelle, which can reduce the performance of the turbomachine. Furthermore, the complex shapes of the cover(s) and the nacelle require seals with a well-defined shape to ensure continuous sealing and to avoid damage when the covers are closed.

[0006] Document LIS-A1 -2016 / 017738 describes two elements fixed relative to each other. One of the elements comprises a groove in which a rib of the other element is housed. A seal is also arranged in the groove and in particular between the two elements to fill only the space formed between the two elements. The rib does not compress the seal.

[0007] Document US-A1-2013 / 298524 describes two elements with a sealing element disposed between joined ends of the two elements. The elements are devoid of a groove receiving the sealing element. A removable flange is intended to cover the joined ends of the two elements.

[0008] There is therefore a need to resolve all or part of the above-mentioned drawbacks. Summary of the invention

[0009] The objective of the present invention is to provide a solution making it possible to reduce as much as possible the risks of aerodynamic leaks and fire at the connections between a part of at least one movable cowl of the nacelle (only when opening the maintenance cowl for maintenance operations) and a fixed part of the casing of the turbomachine.

[0010] We achieve this objective in accordance with the invention by means of a connecting device for an aircraft propulsion unit comprising a first element of a cowl and a second element of a casing centered on a longitudinal axis, the second element comprising a groove extending at least partly around the longitudinal axis, being open towards the outside and being provided with a bottom in which is arranged a first sealing element extending at least partly around the longitudinal axis, the first element being rotatable relative to the casing between a closed position and an open position, and comprising a rib capable of compressing at least partly the first sealing element, radially relative to the longitudinal axis, in the closed position, the connecting device comprising a second sealing element which is arranged between the first sealing element and the first element of the cover at least in the closed position, the second sealing element being arranged so as to radially compress the first sealing element in the closed position and in a direction substantially parallel to the longitudinal axis.

[0011] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, the arrangement of this second sealing element makes it possible to reinforce and optimize the sealing at the connection between the cover and the casing, particularly in the closed position to avoid impacting the drag during operation of the turbomachine.

[0012] The connecting device also includes one or more of the following features, taken alone or in combination: - the groove comprises a first wall and a second wall extending on the one hand radially and on the other hand at least partly around the longitudinal axis, each first wall and second wall facing each other and being provided with a through notch along the longitudinal axis and opening into the groove, the second sealing element extending through the notches in the closed position. - the second element comprises a partition which rises in a direction substantially transverse to a circumferential direction around the longitudinal axis, the second sealing element being capable of bearing tangentially, in the closed position, against a stop surface defined in a substantially radial plane. - the rib comprises a cutout passing transversely through it and in which the second sealing element is arranged by complementary shape. - the second sealing element is fixed on the rib. - the second sealing element is attached and separate from the rib. - the first sealing element and the second sealing element are formed from a single piece.

[0013] The invention relates to a propulsion assembly comprising an aircraft turbomachine equipped with an annular casing, at least one cowl mounted to move relative to the casing, a hanging mast intended to hang the turbomachine from the aircraft and a connecting device as described above. According to an advantageous characteristic of this propulsion unit, two second sealing elements extend substantially on either side of the attachment mast. According to another advantageous characteristic of this propulsion unit, the second sealing elements are arranged by analogy to the dial of a clock respectively at 1 o'clock and 11 o'clock.

[0014] The invention also relates to an aircraft equipped with such a propulsion unit. Brief description of the figures

[0015] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly on reading the detailed explanatory description which follows, of embodiments of the invention given as purely illustrative and non-limiting examples, with reference to the appended schematic drawings in which: - Figure 1 is a radial sectional view of an example of a propulsion assembly connected to an aircraft wing according to the invention; - Figure 2 schematically represents a connecting device between a first element of a nacelle cover and a second element of a stator casing according to the invention; - Figure 3 is a top and perspective view of an example of a connecting device comprising sealing elements according to the invention; - Figure 4 is an axial sectional view of the connecting device according to Figure 3; - Figure 5 is a radial sectional and detailed view of the connecting device according to Figure 3; - Figure 6 is a front view of the connecting device according to Figure 3; and - Figure 7 is a perspective and transparent view of an example of a connecting device according to the invention. Detailed description of the invention

[0016] Figure 1 represents a propulsion assembly 1 intended to be mounted on an aircraft 2, such as an airplane. The propulsion assembly 1 comprises a turbomachine 3 with longitudinal axis X and a nacelle 4 surrounding the turbomachine 3.

[0017] The propulsion unit 1 preferably comprises a suspension mast 5 or pylon which is known by the English acronym “EMS” for “Engine Mounting Structure” and which is configured so as to connect the turbomachine 3 to a structure of one of the wings 6 of the aircraft 2. Preferably, the turbomachine 3 is suspended below the wing 6. In other configurations, the turbomachine 3 can be arranged above the wing 6 or behind the fuselage.

[0018] The turbomachine 3 may be a turboprop having an unducted propeller known as an “open rotor” or “unducted fan” or “open fan”, or having two unducted and counter-rotating propellers (known as “UDF” for “Unducted Dual Fan”), or having a single unducted propeller and a rectifier, also unducted, which comprises several stator blades (known as “USF” for “Unducted Single Fan”). The turbomachine 3 may also be a turbojet, in particular a double-flow and double-spool turbojet, and comprises a fan.

[0019] The invention applies generally to a turbomachine which comprises a fan or a propeller which is shrouded or unshrouded.

[0020] In the present invention, and generally, the terms "upstream", "downstream", "axial" and "axially" are defined with respect to the circulation of gases in the turbomachine and with respect to the longitudinal axis X of the turbomachine. Similarly, the terms "radial", "radially", "internal" and "external" are defined with respect to a radial axis Z perpendicular to the longitudinal axis X and with respect to the distance from the longitudinal axis X.

[0021] The turbomachine is equipped with a casing 7, in particular an external casing, which surrounds and / or structurally supports at least parts of the compressor assembly (not shown), the combustion chamber (not shown) and the turbine assembly (not shown) of the turbomachine 3. The casing 7 is centered on the longitudinal axis X.

[0022] The casing 7 is, advantageously, extended downstream by an ejection structure (not shown) or ejection nozzle which is generally one of the elements of the nacelle.

[0023] The nacelle 4, centered on the longitudinal axis X, surrounds the casing 7, advantageously forming an aerodynamic external surface 8. The nacelle 4 advantageously comprises cowls 9 which are movable relative to the rest of the nacelle 4. These movable cowls 9 may be fan cowls, thrust reverser cowls, or maintenance cowls which allow access to certain parts of the turbomachine for maintenance. Advantageously, the maintenance cowls are without a thrust reverser and do not pivot when the turbomachine is operating. The maintenance cowls advantageously make it possible to delimit the nacelle and to channel the secondary airflow (or external airflow). In a known manner, the thrust reversers make it possible to slow down the aircraft by diverting the airflow (in particular the secondary airflow) upstream.

[0024] When the turbomachine 3 is a turbojet, the nacelle 4 delimits an air inlet opening into the fan and comprises, from upstream to downstream, fan cowls, thrust reverser cowls or maintenance cowls, and an ejection cowl or secondary flow ejection nozzle.

[0025] A primary flow advantageously passes through the compressor assembly, the combustion chamber and the turbine assembly in a primary vein (not shown). The secondary air flow circulates around the primary vein.

[0026] Advantageously, the movable covers 9 are each in the form of half-shells or half-cylinders. In other words, the covers 9 are mounted on either side of a radial plane passing through the attachment mast 5. Other installation configurations of the covers are possible.

[0027] With reference to Figure 1, each hood 9 of the nacelle 4 is pivotally mounted about an axis A parallel to the longitudinal axis X between an open position and a closed position. Each hood 9 comprises an end 9a advantageously articulated on the attachment mast 5. The pivoting can be achieved using a well-known hinge system (not shown). Each hood 9 comprises a free end 9b which is advantageously intended to lock to a free end 9b of the opposite hood 9 when the hood 9 is closed. Alternatively, each free end 9b of a hood is locked to the casing 7. For this, a locking device (not shown) is provided with locks for example (latches in English).

[0028] In Fig. 2 is shown a connecting device 10 between a first element 11 of a cover 9 of the nacelle 4 and a second element 12 of the casing 7. Advantageously, but not limitatively, there is a connecting device 10 between each cover and the casing 7. Preferably, the or each connecting device 10 is arranged close to the attachment mast 5.

[0029] The second element 12 comprises a groove 13 which extends at least partly around the longitudinal axis X. The groove 13 has a U or V shape and is preferably open radially outwards. Advantageously, the groove 13 comprises a first wall 14 and a second wall 15 which each extend on the one hand, at least partly around the longitudinal axis X and on the other hand, radially. Each first wall 14 and second wall 15 is arranged opposite one another.

[0030] According to an exemplary embodiment, two groove portions (only one of which is shown in Figures 2, 3, 4 and 7) extend on either side of a radial plane containing the longitudinal axis X and over a sector between 12 o'clock and 6 o'clock (by analogy with the dial of a clock). Advantageously, but not limitingly, there is no groove portion at 6 o'clock and 12 o'clock, and over a sector which is between 10° and 20° around the longitudinal axis X. In other words, the groove 13 is not annular over 360°. Advantageously, but not limitingly, the attachment mast 5 separates two groove portions 13 around the longitudinal axis X. Each groove portion comprises a first wall 14 and a second wall 15 which extend for example on either side of the attachment mast 5.

[0031] Each groove 13, or groove portion, comprises a bottom 16 in which a first sealing element 17 is arranged. The bottom 16 is connected to the first wall 14 and to the second wall 15 which rise from it. The first sealing element 17 extends at least partly around the longitudinal axis X.

[0032] Advantageously, there is a first sealing element 17 in each groove portion. Advantageously, but not limitingly, each first sealing element 17 has a length substantially equal to a groove portion.

[0033] In the remainder of this description, the term "throat" is used for a throat or a portion of a throat.

[0034] The first sealing element 17 is preferably an O-ring centered on the longitudinal axis X. The latter is made, for example, of a material elastomeric polymer or a thermoplastic polymer material or a thermoplastic elastomer. Preferably, the material is a rubber.

[0035] Preferably, the first sealing element 17 is fixed, for example by gluing, to the bottom of the groove 13.

[0036] The first element 11 of the cover 9 is movable in rotation or pivoting around the longitudinal axis X relative to the casing 7. The first element 11 advantageously comprises a rib 20 (known as a knife) which is capable of being positioned opposite a part of the first sealing element 17.

[0037] Advantageously, the rib 20 extends from an internal face 21 of the cover 9. Preferably, the rib 20 compresses the first sealing element 17 radially when the cover 9 (or the first element 11) is in the closed position. For this purpose, the rib 20 engages inside the groove 13 by complementary shape. Advantageously, but not limitingly, the rib 20 has a shape complementary to that of the groove 13.

[0038] According to the example shown in Figure 2, the second wall 15 comprises an internal face 15a which is flat, defined in a radial plane, and against which a flat face 20a of the rib 20 comes into contact. The first wall 14 comprises an internal face 14a which is flat, defined for example in a plane inclined relative to the radial axis and against which a flat face 20b of the rib 20 comes into contact.

[0039] The arrangement of such a sealing element 17 and such an interpenetration of the rib 20 and the groove 13 makes it possible to ensure a fluid seal, in particular an air seal, between each cover 9 and the casing 7, in particular in the closed position.

[0040] With reference to Figure 3 and Figure 4, the connecting device 10 comprises at least one second sealing element 22 which is configured so as to provide sealing continuity at the groove. Advantageously, the second sealing element is arranged, at least in part, radially between the first element 11 of the cover 9 and the first sealing element 17, in particular at least in the closed position. Advantageously, the second sealing element 22 is arranged so as to compress the first sealing element 17 in the closed position. According to an exemplary embodiment, the second sealing element 22 extends at least in part into the groove 13 during the compression of the first sealing element 17.

[0041] Preferably, the second sealing element 22 extends at least partly in a direction substantially parallel to the longitudinal axis X at the level of the groove 13. In particular, the direction of the second sealing element 22 is parallel to the longitudinal axis X or has an inclination relative to the longitudinal axis X.

[0042] Each first wall 14 and second wall 15 is provided with a notch 23 extending through the longitudinal axis X and opening into the interior of the groove 13. Advantageously, but not limitingly, the notches 23 are open towards the outside and open onto a free edge 13a of the first and second walls of the groove 13. The second sealing element 22 extends through the notches 23. In this way, there is continuity of the second sealing element 22 at the level of the groove 13, preferably on either side of the groove 13 (along the longitudinal axis X), and an optimization of the airtightness. In particular, the second sealing element 22 is located inside the groove 13 only between the notches 23 and when the cover 9 is in the closed position.

[0043] The notches 23 have a shape allowing the passage of the second sealing element 22 and can for example be U-shaped, V-shaped or C-shaped. The second sealing element 22 being continuous at this location, can make it possible to provide sealing in other areas of the nacelle 4 and the casing 7 without breaking the seal.

[0044] According to an exemplary embodiment, the second sealing element 22 is continuous and extends on either side of the attachment mast 5 between a first end and a second end. The first end and the second end are connected to the attachment mast 5 and extend around the longitudinal axis X. The second sealing element 22 comprises a first radial portion connected to the first end and to the second end, and which extends in a radial direction. Then, each first radial portion is connected to a second portion which extends in a circumferential direction (around the longitudinal axis) and which is connected to a third portion along the longitudinal axis X by crossing the groove 13. Each third portion having crossed the groove 13 is connected to a fourth arc-shaped portion extending in the circumferential direction.

[0045] According to an advantageous characteristic, shown in particular in Figures 5 and 6, the rib 20 comprises a cutout 24 passing through the wall of the rib 20 on either side and in a transverse direction relative to the direction of elongation of the rib 20. The direction of elongation of the rib is parallel to the longitudinal direction X in the closed position. The second sealing element 22 is advantageously installed in the notch 23.

[0046] The cutout 24 has, in this embodiment, a U, C or V shape or another shape provided that it allows the arrangement of the second sealing element 22.

[0047] The second sealing element 22 preferably has a shape or at least a part of a shape substantially complementary to that of the cutout 24.

[0048] Each cutout 24 is open inwards (in particular towards the longitudinal axis X in the closed position). The opening of the cutout 24 opens, for example, onto an internal edge 25 of the rib 20.

[0049] The second sealing element 22 has a lower face 26 which is flush with the inner edge 25 of the rib 20. The lower face 26 is in contact with the first sealing element 17 in the closed position. The inner edge 25 of the rib is in contact with the first sealing element 17. The second sealing element 22 completes the missing part (by the cutout 24) and participates in the continuous sealing between the rib 20 and the groove 13.

[0050] Advantageously, the second sealing element 22 is made of an elastomeric polymer material, a thermoplastic polymer material or a thermoplastic elastomer. Preferably, the second sealing element 22 is made of rubber. Such a material is very economical and can make it possible to obtain complex shapes. Alternatively, the second sealing element 22 is made of a composite material. The composite material may comprise fibers (for example glass fibers) making it possible to provide additional functions such as for example fire resistance. According to yet another alternative, the second sealing element 22 is made of a material similar to that of the first sealing element 17 or of a material compatible with that of the first sealing element 17.

[0051] According to an exemplary embodiment, the second sealing element 22 has a parallelepiped shape. Such a shape is simple to produce and allows better contact and consequently better sealing with the first sealing element 17.

[0052] According to an advantageous characteristic, the second sealing element 22 is carried by the annular element 11 of the cover 9. In particular, the second sealing element 22 is fixed to the annular element. The fixing can be permanent or removable. The fixing of the second sealing element 22 is for example gluing, clipping or molding on the cover 9. By fixing the second sealing element 22 on the hood, closing of the hood is simplified and any play between the hood 9 and the second sealing element 22 is reduced, in particular when opening the hood 9.

[0053] Alternatively, the second sealing element 22 is formed in one piece with the first sealing element 17. In this case, the second sealing element 22 and the first sealing element 17 are preferably fixed in the groove 13 and the assembly is facilitated by reducing the handling. The materials of the two sealing elements 17, 22 in one piece may be different and / or have different properties.

[0054] According to yet another alternative, the second sealing element 22 is separate from the cover 9 and from the first sealing element 17. In other words, the second sealing element 22 is an added part. Such a configuration makes it possible to simplify manufacturing and to replace the second sealing element 22 in the event of deterioration thereof.

[0055] With reference to Figure 7, the first element 11 of the cover 9 here comprises a support 30 which makes it possible to reinforce the holding of the second sealing element 22 following its elongation and to guide the latter. The support 30 extends on either side of the cutout 24 from an external surface 27 of the rib 20, in the transverse direction. In the present exemplary embodiment, the support 30 has an L-shaped radial section. The second sealing element 22 is fixed and / or bears against the support 30. The fixing can be carried out for example by gluing, molding or clipping.

[0056] According to another advantageous characteristic, the second element 12 of the casing 7 comprises a partition 31 which rises substantially transversely to the circumferential direction around the longitudinal axis X. In particular, the partition 31 comprises a stop surface 32 defined in a plane which is radial or which has an inclination relative to the radial axis. The partition 31 also extends substantially (+ / - 20° for example) along the longitudinal axis X.

[0057] Advantageously, but not limitatively, the second sealing element 22 bears tangentially against a stop surface of the first element 11. Preferably, the stop surface is that of the partition 31. Advantageously, a first lateral face 33 of the second sealing element 22 provides a flat support connection with the stop surface 32. In this exemplary embodiment, the first lateral face 33 is opposite a second lateral face 34 which is secured to a wall of the support 30.

[0058] The second sealing element 22 ensures, through contact with the first sealing element 17 and the abutment surface 32, a seal in two directions, namely radial and tangential. The second sealing element 22 is compressed onto the partition 31 and onto the first sealing element 17.

[0059] According to an embodiment not shown, the second sealing element 22 may comprise wings or extensions extending from the edge 26 so as to increase the contact area with the first sealing element 17.

[0060] According to one embodiment, a second sealing element 22 is arranged at approximately 1 o'clock by analogy with the dial of a clock. The position is represented for example by a dotted circle in Figure 1. Another second sealing element would be positioned at 11 o'clock (opposite that arranged at 2 o'clock) by analogy with the dial of this clock. In other words, the groove 13 comprises notches 23 arranged substantially at 1 o'clock and 11 o'clock on the dial of a clock.

Claims

Claims [1] Connecting device (10) for an aircraft propulsion unit comprising a first element (11) of a cowl (9) and a second element (12) of a casing (7) centered on a longitudinal axis (X), the second element (12) comprising a groove (13) extending at least partly around the longitudinal axis (X), being open towards the outside and being provided with a bottom (16) in which is arranged a first sealing element (17) extending at least partly around the longitudinal axis (X), the first element (11) being rotatable relative to the casing (7) between a closed position and an open position, and comprising a rib (20) capable of compressing at least partly the first sealing element (17), radially relative to the longitudinal axis (X), in the closed position,characterized in that the connecting device (10) comprises a second sealing element (22) which is arranged between the first sealing element (17) and the first element (11) of the cover (9) at least in the closed position, the second sealing element (22) being arranged so as to radially compress the first sealing element (17) in the closed position and in a direction substantially parallel to the longitudinal axis (X)., [2] Connecting device (10) according to claim 1, characterized in that the groove (13) comprises a first wall (14) and a second wall (15) extending on the one hand radially and on the other hand at least partly around the longitudinal axis (X), each first wall (14) and second wall (15) facing each other and being provided with a notch (23) passing through the longitudinal axis (X) and opening into the groove (13), the second sealing element (22) extending through the notches (23) in the closed position. [3] Connecting device (10) according to claim 1 or 2, characterized in that the second element (12) comprises a partition (31) which rises in a direction substantially transverse to a circumferential direction around the longitudinal axis (X), the second sealing element (22) being able to bear tangentially, in the closed position, against a stop surface (32) defined in a substantially radial plane. [4] Connecting device (10) according to one of the preceding claims, characterized in that the rib (20) comprises a cutout (24) passing transversely therethrough and in which the second sealing element (22) is arranged by complementary shape. [5] Connecting device (10) according to one of claims 1 to 4, characterized in that the second sealing element (22) is fixed to the rib (20). [6] Connecting device (10) according to one of claims 1 to 4, characterized in that the second sealing element (22) is attached and separate from the rib (20). [7] Connecting device (10) according to one of claims 1 to 4, characterized in that the first sealing element (17) and the second sealing element (22) are formed from a single piece. [8] Propulsion assembly (1) comprising an aircraft turbomachine (1) equipped with an annular casing (7), at least one cowl (9) mounted to move relative to the casing (7), a hanging mast (5) intended to hang the turbomachine from the aircraft (2) and a connecting device (10) according to any one of the preceding claims. [9] Propulsion assembly (1) according to the preceding claim, characterized in that two second sealing elements (22) extend substantially on either side of the attachment mast (5). [10] Propulsion assembly (1) according to the preceding claim, characterized in that the second sealing elements (22) are arranged by analogy with the dial of a clock respectively at 1 o'clock and 11 o'clock.

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