Opening hood for turbomachine

Abstract

The invention relates to a propulsion assembly (1) for an aircraft extending along a longitudinal axis (X) comprising a turbomachine (2), a pylon (3) which connects the turbomachine (2) to the wing of the aircraft, an internal fairing (4) which surrounds the turbomachine (2), an external fairing (5) which circumferentially surrounds the internal fairing (4) and which comprises a hollow right-hand cover (10A) with an internal space and a hollow left-hand cover (10B) with an internal space which are capable of passing between a closed position and an open position.Each of the covers (10A, 10B) comprises an upper part (20A, 20B) located under the pylon (3) in the closed position and the internal space of which forms an upstream vein (V2A, V2B) which flares laterally from upstream to downstream, and comprises a lower part (30A, 30B) which circumferentially extends the upper part (20A, 20B) downwards in the closed position, and in that the internal space of the lower part (30A, 30B) of each of the covers (10A, 10B) forms a downstream vein (V3A, V3B) which extends the upstream vein (V2A, V2B). Figure 2.

Description

Title of the invention: Opening hood for turbomachine

[0001] The present invention relates to the field of aircraft propulsion systems, in which the propulsion system comprises a turbomachine, a nacelle which surrounds the turbomachine and a mast or pylon which connects the turbomachine to the aircraft.

[0002] The propulsion assembly and the turbomachine extend along a longitudinal axis X which is the axis of rotation of the turbomachine and which corresponds to the direction of flow of the air and gas flow during normal operation of the propulsion assembly. Upstream and downstream are defined relative to this direction of flow of the air and gas. The turbomachine comprises a gas generator, and the nacelle comprises an internal fairing and an external fairing which radially surrounds this external fairing. An annular space is defined radially inwardly by the internal fairing and radially outwardly by the external fairing.

[0003] The external fairing comprises two C-shaped covers on either side of a first plane V which separates the turbomachine in two in the longitudinal direction and comprises the longitudinal axis X. In the case where the turbomachine is attached under the wing of the aircraft, the first plane V is vertical and therefore passes through the middle of the pylon. Alternatively, the turbomachine can be attached laterally to the fuselage of the aircraft. In the closed position, each of these covers surrounds a half-circumference of the turbomachine. Each of the covers has a radially external circumferential wall and a radially internal circumferential wall. In the open position, each of these covers rises radially outwards to allow maintenance of the turbomachine. Each of the covers is articulated at its upper end on one side of the pylon by a pivot connection which allows the passage between its closed position and its open position.

[0004] Thus, the present invention relates to a propulsion unit for an aircraft extending along a longitudinal axis X which corresponds to the direction of flow of the gas in normal operation of this propulsion unit and which defines an upstream and a downstream, this propulsion unit comprising a turbomachine, a pylon which connects the turbomachine to the aircraft, an internal fairing which surrounds the turbomachine, an external fairing which circumferentially surrounds the internal fairing and which comprises a first hollow cover with an internal space and a second hollow cover with an internal space which extend symmetrically from upstream to downstream along the longitudinal axis X relative to a first plane V passing through the longitudinal axis X and which are capable of passing between a closed position and an open position.

[0005] In the case where the propulsion assembly 1 is attached under the pylon 3, the propulsion assembly 1 comprises a bifurcation 106 which is located under the front (upstream) partof the pylon 3, and which has a U-shaped structure, the apex of which is directed upstream (i.e. to the right in the figure), and the width of which is at least equal to the width L of the pylon 3 above. The bifurcation 106 is fixed relative to the turbomachine 2. The bifurcation 106 extends vertically under the pylon 3 over a certain height, along a first axis Z which is perpendicular to the longitudinal axis X and which extends in the first plane V. The first axis Z crosses the upstream part of the pylon 3 and the cowls (110A, 110B). The upstream air flow which comes from the upstream region of the turbomachine 2 is separated into a right lateral flow and a left lateral flow. The upper ends (120A, 120B) of the covers (110A, 110B) have internal lateral edges (121A, 121B) which delimit radially inwards (in the direction of the vertical plane V) the internal space of these hollow covers (110A, 110B).When the covers (110A, 110B) are in the closed position, these internal lateral edges (121A, 121B) extend the bifurcation 106 downstream such that the right lateral flow (respectively left lateral flow) then flows downstream into the internal space of the remainder of the right cover 110A (respectively left cover 110B). Since the width of the bifurcation 106 is at least equal to the width L of the pylon 3, the covers (110A, 110B) do not pass under the pylon 3 and the lateral flows do not pass under the pylon 3. This situation is illustrated in [Fig. 11] which is a top view section of the hoods (110A, 110B) and the bifurcation 106 in a plane H perpendicular to the vertical axis Z and which passes under the pylon 3. The flow of gas in the internal spaces of the hoods (110A, 110B) is represented by arrows. [Fig.[Fig. 11] is a section in a vertical plane perpendicular to the longitudinal axis X, immediately downstream of the bifurcation 106 (section XILXII in [Fig. 11]). [Fig. 11] and [Fig.l2A] show the hoods (110A, 110B) in the closed position. [Fig.l2B] is a figure similar to [Fig.l2A] which shows the hoods (110A, 110B) in the open position. The upper ends (120A, 120B) of the covers (110A, 110B) are hinged to the lateral sides of the pylon 3. When the covers (110A, 110B) are in the closed position, the upper ends (120A, 120B) are not located under the pylon 3. The plane H passes through the upper ends (120A, 120B) of the covers (110A, 110B) in the closed position.

[0006] The significant width of the bifurcation 106 disturbs the flow of gases in the region upstream of the pylon 3, and in particular in the compressor of the turbomachine, which is undesirable. Description of the invention

[0007] The present invention aims to remedy these drawbacks.

[0008] The invention aims to propose a propulsion assembly for an aircraft in which a pylon connects the turbomachine to the aircraft, and in which the flow of gases upstream of the pylon is disturbed as little as possible.

[0009] This aim is achieved by the fact that each of the covers comprises a proximal part which is located close to the pylon in the closed position and the internal space of which forms an upstream vein which flares laterally from upstream to downstream, and comprises a distal part which circumferentially extends the proximal part in the closed position, and in that the internal space of the distal part of each of the covers forms a downstream vein which extends downstream and laterally the upstream vein.

[0010] Thanks to these arrangements, when the cowls are in the closed position, the passage section of the vein in which the gases circulate downstream of the compressor of the turbomachine is increased. Indeed, the gases are able to circulate through the proximal parts of the cowls which extend close to the pylon in addition to circulating through the portion of the distal parts of the cowls which extend laterally and around the propulsion assembly these upper parts.

[0011] For example, for each of the hoods the proximal part is integral with the distal part such that the proximal parts and the distal parts pivot when passing between the closed position and the open position.

[0012] Thus, the structure of the hoods is simplified because each hood is in one piece.

[0013] For example, the proximal portions are integral with each other such that they are static between the open position and the closed position of the covers and the distal portions pivot when passing between the closed position and the open position.

[0014] Thus, the area swept by the upper parts of the cowls in their movement between the closed position and the open position is minimized, which frees up more space for the turbomachine equipment located under the cowls. In addition, access to the internal fairing and to this equipment, for example for maintenance, is facilitated.

[0015] For example, the proximal portions are attached to the pylon by a pylon attachment.

[0016] For example, the proximal parts are fixed to the turbomachine by a fixing engine.

[0017] For example, the distal portions include cover seals between the proximal portions and the distal portions that establish a seal between the upstream vein and the downstream vein when the covers are in the closed position.

[0018] For example, the propulsion assembly comprises a transverse force recovery device on which the distal parts come to bear when the covers are in the closed position.

[0019] For example, the proximal portions include pylon joints between the proximal portions and the pylon.

[0020] For example, each of the distal parts is carried by a longitudinal beam which is articulated relative to the pylon to allow pivoting of each of the covers between the closed position and the open position.

[0021] For example, the propulsion assembly includes a centering mechanism that allows the distal portions to be aligned with the proximal portions in the closed position of the covers.

[0022] The invention will be better understood and its advantages will appear better on reading the detailed description which follows, of embodiments shown as non-limiting examples. The description refers to the appended drawings in which:

[0023] [Fig-1] [Fig.l] is a perspective view from the rear of the propulsion unit according to the invention.

[0024] [Fig.2] [Fig.2] is a schematic sectional view from above in a plane horizontal of the hoods near the pylon of the propulsion unit of [Fig.l] according to a first embodiment of the invention.

[0025] [Fig.3A]-[Fig.3B] [Fig.3A] is a sectional view along plane III-III of [Fig.2] with the hoods in the closed position; [Fig.3B] is a sectional view along plane III-III of [Fig.2] with the hoods in the open position.

[0026] [Fig.4] [Fig.4] is a top view section in a horizontal plane of the hoods near the pylon according to a second embodiment of the invention.

[0027] [Fig.5] [Fig.5] is a perspective view from below of the nearby hoods of the pylon according to the second embodiment of the invention.

[0028] [Fig.6] [Fig.6] is a perspective and sectional view from the front in a vertical plane of the hoods according to the second embodiment of the invention with the hoods in the closed position.

[0029] [Fig.7] [Fig.7] is a perspective view from the rear showing the propulsion unit according to the second embodiment of the invention with the covers in the open position.

[0030] [Fig.8] [Fig.8] is a perspective and sectional view from the front in a vertical plane of the hoods according to the second embodiment of the invention with the hoods in the open position.

[0031] [Fig.9] [Fig.9] is a perspective view from the rear showing the propulsion unit according to a third embodiment of the invention with the covers in the open position, zooming in on the region immediately under the pylon

[0032] [Fig. 10] [Fig. 10] is a view similar to [Fig.9], viewed from the front instead of from the back.

[0033] [Fig. 11] [Fig. 11], already described, is a sectional view of portions of hoods of a propulsion unit according to the prior art with attachment of the propulsion unit under the pylon.

[0034] [Fig. 12A]-[Fig. 12B] [Fig.l2A], already described, is a sectional view along plane XII-XII of [Fig. 11] with the hoods in the closed position; [Fig.l2B], already described, is a sectional view along plane XII-XII of [Fig.l 1] with the hoods in the open position. Detailed description of the invention

[0035] Consider a propulsion unit 1 for an aircraft extending along a longitudinal axis X which corresponds to the direction of flow of the gas in normal operation of this propulsion unit and which defines an upstream (front) and a downstream (rear) and first and second sides when this propulsion unit 1 is viewed from the front. In the following description, the adjectives "front" and "rear" are defined relative to the direction from upstream to downstream in this longitudinal direction. Taking into account the symmetry, the letter "A" after a part reference number designates this part on the first right side and the letter "B" after a part reference number designates this part on the second side.

[0036] Such a propulsion unit 1, shown in [Fig.l] in perspective from the rear, comprises a turbomachine 2, a pylon 3 which connects the turbomachine 2 to the wing of the aircraft, an internal fairing 4 which surrounds the turbomachine 2 and an external fairing 5 which circumferentially surrounds the internal fairing 4. The longitudinal axis X is the axis of rotation of the turbomachine 2. A portion of the internal fairing 4 is shown in dotted lines in [Fig.l] because it is hidden by the external fairing 5. The external fairing 5 comprises a first hollow cover 10A and a second hollow cover 10B which extend symmetrically from upstream to downstream along the longitudinal axis X relative to a first plane V passing through the longitudinal axis X. A first axis Z is defined which extends in the first plane V, which is perpendicular to the longitudinal axis X and which crosses the upstream part of pylon 3 and the hoods (10A, 10B).A second plane H is defined which is perpendicular to the vertical axis Z and which passes just near the pylon 3 so as to cross the ends of the cowls (10A, 10B), as illustrated in [Fig.l]. In the description below, the pylon 3 is located above the propulsion unit 1. The first plane V is therefore vertical, and the second plane H is horizontal. The cowls (10A, 10B) are located below the pylon 3. The first cowl 10A is the right cowl and the second cowl 10B is the left cowl. However, the invention also covers the case where the propulsion unit 1 is mounted laterally on the fuselage, in which case the pylon is lateral with respect to the cowls (10A, 10B), the first plane V is horizontal and the second plane H is vertical. The description below is therefore valid to cover this case, replacing the adjectives as necessary. In particular, "right" is replaced by "first" and "left" is replaced by "second". “superior” is replaced by “proximal” and “inferior” is replaced by “distal”.

[0037] The covers (10A, 10B) are capable of passing between a closed position and an open position. In the closed position, as shown in [Fig.l], each of the covers (10A, 10B) forms half of an annular shell which extends from a proximal (upper) end which is closest to the pylon 3 around the internal fairing 4 to the vertical plane V. Thus, the distal (lower) end of the right cover 10A joins the distal (lower) end of the left cover 10B at the level of the vertical plane V. In the open position, each of the covers (10A, 10B) rises radially outwards to allow access to the internal fairing 4 and to the turbomachine 2. The right cover 10A (respectively left cover 10B) is articulated at its upper end on the pylon 3 by a right articulation 90A (respectively left 90B) which allows by pivoting the passage between its closed position and its open position. The left joint 90B is hidden by pylon 3 in [Fig.l].

[0038] For example, these articulations (90A, 90B) are direct pivot connections between the covers (10A, 10B) and the pylon 3, as illustrated in FIGS. 3A and 3B. Alternatively, each of the covers (10A, 10B) is carried by a longitudinal beam (40A, 40B) which is articulated relative to the pylon 3 by a pivot connection, as described in more detail below.

[0039] The right cover 10A (respectively left 10B) has a right radially internal circumferential wall 12A (respectively left 12B) and a right radially external circumferential wall 13A (respectively left 13B), with an internal space between these walls.

[0040] According to the invention, the right cover 10A (respectively left 10B) comprises a right upper part 20A (respectively left 20B) which is located under the pylon 3 when the right cover 10A (respectively left 10B) is in the closed position. The internal space of the upper part 20A (respectively left 20B) forms a right upstream vein V2A (respectively left V2B) which widens laterally from upstream to downstream. The right upstream vein V2A (respectively left V2B) is delimited laterally inwards (i.e. towards the vertical plane V) by an internal lateral edge 21A (respectively left 21B) of the right upper part 20A (respectively left 20B).

[0041] [Fig. 2] is a schematic sectional view from above in the horizontal plane H of the cowls (10A, 10B) near the pylon 3. The propulsion unit 1 comprises a bifurcation 6 which is located under the front (upstream) part of the pylon 3 and symmetrical with respect to the vertical plane V. The bifurcation 6 is integral with the turbomachine 2 and has a U-shaped structure, the apex of which is directed upstream (i.e. to the left in the figure). The width of the bifurcation 6 is strictly less than the width L of the pylon 3 above, for example less than half the width L, for example less than a quarter of the width L. The upstream air flow which comes from the upstream region of the turbomachine 2 is separated into a right lateral flow and a left lateral flow by the bifurcation 6. When the cowls (10A, 10B) are in the closed position, the radially internal edges (21A, 21B) of the upper parts (20A, 20B) extend the bifurcation 6 downstream in such a way that the right lateral flow (respectively left lateral flow) then flows downstream in the right upstream vein V2A (respectively left V2B). The right upstream vein V2A (respectively left V2B) has a U-shaped cross-section open laterally towards the outside. For example, the radially internal edges (21A, 21B) are convex (seen from the outside of the upper parts (20A, 20B), i.e. from the vertical plane V).

[0042] The right hood 10A (respectively left 10B) comprises a lower right part 30A (respectively left 30B) which circularly and downwardly extends the upper right part 20A (respectively left 20B) in the closed position. The lower parts (30A, 30B) do not extend under the pylon 3, that is to say they extend the upper parts (20A, 20B) laterally outside the region located under the pylon 3. In other words, for each hood (10A, 10B), the boundary between the upper part (20A, 20B) and the lower part (30A, 30B) is located at the boundary of the region under the hood 3. The internal space of the lower part 30A (respectively left 30B) forms a right downstream vein V3A (respectively left V3B) which extends downstream and laterally the right upstream vein V2A (respectively left V2B). This situation is illustrated in [Fig.2] which shows the hoods (10A, 10B) in the closed position.In the downstream veins (V3A, V3B) reinforcements (right 36A, left 36B) perpendicularly connect the radially internal circumferential wall (12A, 12B) and the radially external circumferential wall (13A, 13B) of each hood (10A, 10B). These reinforcements (36A, 36B) guide the flow from the upstream veins (V2A, V2B).

[0043] A first embodiment is now described, in which for each of the covers (10A, 10B) the upper part (20A, 20B) is integral with the lower part (30A, 30B) and circumferentially extends this lower part (30A, 30B). Consequently, the upper parts (20A, 20B) pivot with the lower parts (30A, 30B) when passing between the closed position and the open position.

[0044] This situation is illustrated in [Fig.3A] which is a section in a vertical plane perpendicular to the longitudinal axis X, immediately downstream of the bifurcation 6 (section III-III in [Fig.2]). [Fig.3B] is a figure similar to [Fig.3A] which shows the covers (10A, 10B) in the open position. The right articulation 90A (respectively left 90B) by which the right cover 10A (respectively left 10B) is articulated on the right lateral side (respectively left) of the pylon 3 is located at the border between the lower right part 30A (respectively left 30B) and the upper right part 20A (respectively left 20B).

[0045] The disadvantage of this first embodiment is that the upper parts (20A, 20B), in their movement between the closed position and the open position, sweep a large area under the pylon 3, as visible in [Fig.3B]. This prohibits the placement of equipment in this area, and furthermore this hinders access to the internal fairing 4 (see [Fig.1] and [Fig.7] described below) and to the equipment of the turbomachine 2 located downstream and under this area, for example for their maintenance.

[0046] A second embodiment of the invention is described below, which makes it possible to solve this problem and which is illustrated in Figures 4 to 8. [Fig.4] is a sectional view from above in the horizontal plane H of the covers (10A, 10B) near the pylon 3 and below the pylon 3.

[0047] In this second embodiment, the upper right part 20A (respectively left 20B) is integral with respect to the pylon 3 and the upper parts (20A, 20B) are integral with each other such that they are static between the open position and the closed position of the hoods (10A, 10B). The upstream ends of the upper parts (20A, 20B) form the bifurcation 6. The upper parts (20A, 20B) are in one piece, as illustrated in [Fig.4]. Alternatively, the upper parts (20A, 20B) are separate and fixed to each other by fasteners.

[0048] The upper parts (20A, 20B) can be secured to the pylon 3 in different ways, examples of which are given below.

[0049] According to a first solution, the upper parts (20A, 20B) are fixed by a pylon fixing only on the pylon 3. This solution has the advantage of good cohesion and cooperation between the upper parts (20A, 20B) and the lower parts (30A, 30B) because they are all fixed on the pylon 3.

[0050] According to a second solution, the upper parts (20A, 20B) and the bifurcation 6 are fixed by an engine fixing on the turbomachine 2. Towards the rear of the upper parts (20A, 20B), an element (for example a rear transverse bar 80 (see description below and [Fig.5])) is connected to the pylon 3 and contributes to the positioning of the lower parts (30A, 30B) when the cowls (10A, 10B) are in the closed position.

[0051] Alternatively, the upper parts (20A, 20B) are fixed by a pylon fixing on the pylon 3 and by an engine fixing on the turbomachine 2. These fixings must then be able to accommodate relative movements between the pylon 3 and the turbomachine 2, for example comprising elastically deformable elements such as elastomers, springs or joints.

[0052] The upstream air flow coming from the upstream region of the turbomachine 2 is separated into a right lateral flow and a left lateral flow by the upper parts (20A, 20B). When the cowls (10A, 10B) are in the closed position, the right lateral flow (respectively left lateral flow) flows downstream in the right upstream vein V2A (respectively left V2B). The right upstream vein V2A (respectively left V2B) has a U-shaped cross-section open laterally towards the outside. The depth (distance in the transverse direction, perpendicular to the vertical plane V) of the upstream veins (V2A, V2B) decreases from upstream to downstream. The right upstream vein V2A (respectively left V2B) is bordered inwards by the radially internal right edge 21A (respectively left 21B) of the upper right part 20A (respectively left 20B).For example, the radially internal edges (21A, 21B) are convex (seen from the outside of the upper parts (20A, 20B), i.e. from the vertical plane V). [Fig. 5] is a perspective view from below of the covers (10A, 10B) near the pylon 3 which shows the geometry of the upper parts (20A, 20B) which extend transversely under substantially the entire width of the pylon 3.

[0053] When the covers (10A, 10B) move between the closed position and the open position, the lower parts (30A, 30B) move away from the upper parts (20A, 20B) by pivoting laterally outwards. The right articulation 90A (respectively left 90B) by which the right cover 10A (respectively left 10B) is articulated on the right lateral side (respectively left) of the pylon 3 is located on the right lower part 30A (respectively left 30B) at its laterally inner end, that is to say at the border with the right upper part 20A (respectively left 20B). This laterally inner end constitutes the right proximal edge 31A (respectively left 31B) of the right lower part 30A (respectively left 30B).Thus, when the covers (10A, 10B) are in the closed position, the proximal edges (31 A, 31B) of the lower parts (30A, 30B) are positioned opposite the lateral edges (21A, 21B) of the upper parts (20A, 20B). The proximal edges (31 A, 31B) of the lower parts (30A, 30B) are provided with cover seals (35A, 35B) which ensure sealing between the lower parts (30A, 30B) and the upper parts (20A, 20B) by compression between these parts. Thus, the right bonnet seal 35A (respectively left 35B) ensures the seal between the right upstream vein V2A (respectively left V2B) and the right downstream vein V3A (respectively left V3B) of the lower right part 30A (respectively left 30B). These bonnet seals (35A, 35B) are notably visible in [Fig. 5] as well as in figures 6 and 8 described below. As visible in [Fig.8], these hood seals (35A, 35B) follow the contact zone between the lower parts (30A, 30B) and the upper parts (20A, 20B). This contact zone is formed by the edges. proximal (31 A, 31B) which have a U shape open upstream and whose apex is oriented downstream. Thus, the cap seals (35A, 35B) have a U shape arranged identically. Thanks to this upstream opening, the right cap seal 35A (respectively left 35B) does not interfere with the right (respectively left) lateral flow from the right upstream vein V2A (respectively left V2B) to the right downstream vein V3A (respectively left V3B).

[0054] Advantageously, the upper parts (20A, 20B) comprise pylon seals (25A, 25B) between the upper parts (20A, 20B) and the pylon (3). Thus, the right pylon seal 25A (respectively left 25B) ensures the seal between the right upper part 20A (respectively left 20B) and the pylon 3. In particular, these pylon seals (25A, 25B) ensure the thermal seal between the hot region located between the radially internal edges (21A, 21B) and under the upper parts (20A, 20B) and the colder region which comprises the upstream veins (V2A, V2B). These pylon joints (25A, 25B) extend longitudinally under the pylon 3 along the radially internal edges (21A, 21B). These pylon joints (25A, 25B) are notably visible in figures 6 and 8 described below.

[0055] [Fig. 6] is a perspective and sectional view from the front in a vertical plane perpendicular to the longitudinal axis X which passes upstream of the hoods (10A, 10B) at the level of the front transverse bar 70 (see below), with the hoods (10A, 10B) in the closed position. This section is referenced VLVI in [Fig. 5]. This vertical plane is located immediately downstream of the vertical axis Z.

[0056] The lower parts (30A, 30B) are articulated on the pylon 3 by articulations (90A, 90B), as mentioned above. This articulation (90A, 90B) is for example a direct pivot connection between the lower parts (30A, 30B) and the pylon 3. Alternatively, the right lower part 30A (respectively left 30B) is carried by a right longitudinal beam 40A (respectively left 40B) which is articulated directly on the side of the pylon 3 by a pivot connection which constitutes this right articulation 90A (respectively left 90B). This right longitudinal beam 40A (respectively left 40B) extends along the proximal edge 31A (respectively left 31B) of the lower part 30A (respectively left 30B). These configurations are valid for all embodiments.

[0057] In any case, since the pivot axes are located above the lower parts (30A, 30B), the lower parts (30A, 30B) exert a transverse compressive force (perpendicular to the vertical plane V) on the upper parts (20A, 20B) when the covers (10A, 10B) are in the closed position. It is advantageous for the propulsion unit 1 to comprise a transverse force absorption device which absorbs this compressive force so that the upper parts (20A, 20B) do not risk being damaged.

[0058] For example, this transverse force recovery device comprises a front transverse bar 70 which is located towards the front and under these upper parts (20A, 20B). The lower parts (30A, 30B) come to bear on the lateral ends (71 A, 71B) of this front transverse bar 70 when the covers (10A, 10B) are in the closed position. Advantageously, each of the lower parts (30A, 30B) has a cup (32A, 32B) in which a lateral end (71 A, 71B) is housed, and each of the lateral ends (71 A, 71B) is pointed, which facilitates the centering of this lateral end (71 A, 71B) in the cup (32A, 32B). The lateral ends (71A, 71B) rest on the bottom of the cups (32A, 32B). The front crossbar 70 is visible in Figures 5, 6 and 8. [Fig.8] is a view identical to [Fig.6] with the covers (10A, 10B) in the open position.Alternatively, the lower parts (30A, 30B) are positioned relative to the lateral ends (71 A, 71B) of this front crossbar 70 by another centering mechanism. This centering mechanism makes it possible to align the upper parts (20A, 20B) with the lower parts (30A, 30B) in the closed position of the covers (10A, 10B), is part of the propulsion assembly.

[0059] For example, the transverse force recovery device comprises a rear transverse bar 80 which is integral with the upper parts (20A, 20B) and on the ends (81 A, 81B) of which the lower parts (30A, 30B) come to bear when the covers (10A, 10B) are in the closed position. This rear transverse bar 80 is visible in FIGS. 5, 6 and 8.

[0060] [Fig.7] is a perspective view from the rear showing the propulsion unit 1 with the cowls (10A, 10B) in the open position. For clarity, the turbomachine 2 is omitted. [Fig.7] and [Fig.8] show the cowls (10A, 10B) in the open position. The lower parts (30A, 30B) pivot away from the upper parts (20A, 20B) when the cowls (10A, 10B) move from the closed position to said open position. [Fig.8] is a view identical to that of [Fig.6], with the cowls (10A, 10B) in the open position.

[0061] A third embodiment of the invention is described below, which is a variant of the second embodiment and which is illustrated in Figures 9 and 10.

[0062] In this third embodiment, the front crossbar 70 and the rear crossbar 80 are removed. The front crossbar 70 is replaced by two front recovery elements (right 270A and left 270B) which are each an integral part of one of the upper parts (right 20A and left 20B). These two front recovery elements (270A, 270B) join and are fixed at the level of vertical plane V. Similarly, the rear crossbar 80 is replaced by two rear recovery elements (right 280A and left 280B) which are each an integral part of one of the upper parts (right 20A and left 20B). These two recovery elements rear (280A, 280B) join and are fixed at the level of vertical plane V. The two front recovery elements (270A, 270B) and the two rear recovery elements (280A, 280B) are therefore part of the transverse force recovery device. In this embodiment, it is therefore the covers (10A, 10B) which take up the compression forces. This embodiment has the advantage of reducing the size of the joints and the clearances between the various elements. When the hoods (10A, 10B) are in the closed position, the lower parts (30A, 30B) come to bear on front receivers (right 271A and left 27 IB) located on the upper parts (20A, 20B) at the level of the two front recovery elements (270A, 270B) and on rear receivers (right 281A and left 28 IB) located on the upper parts (20A, 20B) at the level of the two rear recovery elements (280A, 280B).For example, the front receivers (271 A, 27 IB) are located at the ends on the front recovery elements (270A, 270B) and the rear receivers (281 A, 28 IB) are located on the rear recovery elements (280A, 280B).

[0063] Advantageously, each of the lower parts (30A, 30B) has a front spigot (pin) (37A, 37B) which is housed in a housing of the front receiver (271 A, 271 B), and a rear spigot (pin) (38A, 38B) which is housed in a housing of the rear receiver (281 A, 281 B). These front (37A, 37B) and rear (38A, 38B) spigots (pins) allow positioning, in particular vertical, of the lower parts (30A, 30B) relative to the upper parts (20A, 20B) when the covers (10A, 10B) are in the closed position. In [Fig.9], the front right spigot (pin) 37A and the rear right spigot (pin) 38A are on the lower right part 30B shown in dotted lines. The spigot (pin) assemblies (37A, 37B, 38A, 38B) and receivers (271 A, 27IB, 281 A, 28 IB) constitute an example of a centering mechanism.

Claims

Claims

1. Propulsion assembly (1) for an aircraft extending along a longitudinal axis (X) which corresponds to the direction of flow of the gas in normal operation of this propulsion assembly and which defines an upstream and a downstream, said propulsion assembly (1) comprising a turbomachine (2), a pylon (3) which connects said turbomachine (2) to the aircraft, an internal fairing (4) which surrounds said turbomachine (2), an external fairing (5) which circumferentially surrounds said internal fairing (4) and which comprises a first hollow cowl (10A) with an internal space and a second hollow cowl (10B) with an internal space which extend symmetrically from upstream to downstream along said longitudinal axis (X) relative to a first plane (V) passing through the longitudinal axis (X) and which are capable of passing between a closed position and an open position, said propulsion assembly (1) being characterized in that each of said cowls (10A, 10B) has a proximal portion (20A,20B) which is located close to said pylon (3) in said closed position and the internal space of which forms an upstream vein (V2A, V2B) which flares laterally from upstream to downstream, and comprises a distal part (30A, 30B) which circumferentially extends said proximal part (20A, 20B) in said closed position, and in that the internal space of said distal part (30A, 30B) of each of the covers (10A, 10B) forms a downstream vein (V3A, V3B) which extends downstream and laterally said upstream vein (V2A, V2B).,

2. Propulsion assembly (1) according to claim 1 such that for each of said covers (10A, 10B) said proximal part (20A, 20B) is integral with said distal part (30A, 30B) such that said proximal parts (20A, 20B) and said distal parts (30A, 30B) pivot when passing between said closed position and said open position.

3. Propulsion assembly (1) according to claim 1 such that said proximal parts (20A, 20B) are integral with each other such that they are static between the open position and the closed position of the covers (10A, 10B) and that said distal parts (30A, 30B) pivot during the passage between said closed position and said open position.

4. Propulsion assembly (1) according to claim 3 such that said proximal parts (20A, 20B) are fixed to said pylon (3) by a pylon attachment.

5. Propulsion assembly (1) according to claim 3 or 4 such that said proximal parts (20A, 20B) are fixed to said turbomachine (2) by an engine fixing.

6. Propulsion assembly (1) according to any one of claims 3 to 5 such that said distal parts (30A, 30B) comprise cover seals (35A, 35B) between said proximal parts (20A, 20B) and said distal parts (30A, 30B) which establish a seal between said upstream vein (V2A, V2B) and said downstream vein (V3A, V3B) when said covers (10A, 10B) are in the closed position.

7. Propulsion assembly (1) according to any one of claims 3 to 6 such that it comprises a transverse force absorption device on which said distal parts (30A, 30B) come to bear when said covers (10A, 10B) are in the closed position.

8. Propulsion assembly (1) according to any one of claims 3 to 7 such that said proximal parts (20A, 20B) comprise pylon joints (25A, 25B) between said proximal parts (20A, 20B) and said pylon (3).

9. Propulsion assembly (1) according to any one of claims 1 to 8 such that each of the distal parts (30A, 30B) is carried by a longitudinal beam (40A, 40B) which is articulated relative to said pylon (3) to allow pivoting of each of said covers (10A, 10B) between said closed position and said open position.

10. A propulsion assembly according to any one of claims 1 to 9 such that it comprises a centering mechanism which makes it possible to align said distal portions (30A, 30B) with said proximal portions (20A, 20B) in said closed position of the covers (10A, 10B).

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