Assembly for an aircraft comprising a turbomachine, a cradle and an attachment system

Abstract

The invention relates to an assembly for an aircraft comprising a turbomachine (1), a cradle (2) comprising an upstream frame (21) and a system (245, 25, 270) for attaching the turbomachine (1) to the cradle (2), the turbomachine extending along a longitudinal axis (XX) and comprising a propeller (3), an upstream casing (4), an intermediate casing (5), a turbine casing (6) and an exhaust casing (7), the attachment system comprising upstream attachment means between the upstream frame and the upstream casing (4), intermediate attachment means between the cradle and the intermediate casing (5) and rear attachment means between the cradle and one of the turbine casing (6) and the exhaust casing (7), the upstream attachment means comprising four coupling means (245) extending toward the propeller from the upstream frame and arranged such that each resultant force taken up by the coupling means has a direction (D) intersecting the longitudinal axis (XX) at the plane P, and wherein either the intermediate attachment means comprise flexible attachment means (25) and the rear attachment means comprise rigid attachment means (270), or the intermediate attachment means comprise rigid attachment means (256) and the rear attachment means comprise flexible attachment means (27).

Description

DESCRIPTION TITLE: Aircraft assembly comprising a turbomachine, a cradle and a mounting system TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to the field of turbomachine attachments to an aircraft. In particular, the invention relates to an aircraft assembly comprising a turbomachine, a cradle, and a system for attaching the turbomachine to the cradle. STATE OF PRIOR ART

[0002] Existing systems for attaching a turbomachine to a pylon or aircraft cradle are described, for example, in documents CA2958686, WO2022 / 245363, WO2022 / 248791 or WO2023 / 198962.

[0003] A turbomachine typically comprises, in one flow direction, an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section. During operation, air enters through the inlet section and flows to the compressor section, where one or more axial compressors progressively compress the air until it reaches the combustion section, where combustion gases are generated. These combustion gases then flow from the combustion section along a defined hot gas path in the turbine section and exit the combustion section through the exhaust section. Such a turbomachine produces thrust capable of propelling a motor vehicle, such as an aircraft.On an aircraft, the thrust generated by the turbomachine produces thrust forces transmitted to a support, such as a pylon or cradle, and similarly, the aircraft applies equal and opposite reaction forces to the support. This load induces a pitching moment or a yaw moment in the turbomachine. It is therefore necessary to reduce these pitching and yaw moments applied to the turbomachine so that it does not deform to the point of degrading its operating performance.

[0004] Indeed, when the turbomachine produces thrust and is subjected to maneuvering loads (aerodynamic forces on a nacelle or propeller associated with the turbomachine), the turbomachine itself is subjected to loads, i.e., thrust, gravity, etc. The bending (or "back-bone bending" according to Anglo-Saxon terminology) of a turbomachine casing, induced by these forces, creates clearance closures, or even wear, degrading the turbomachine's performance, thus increasing fuel consumption and accelerating the turbomachine's aging.

[0005] In the case of unfaired turbomachinery typically used on short- or medium-range aircraft, the turbomachine's mounting is critical because the turbomachine's large-diameter propeller induces significant axial moment loads. Furthermore, to achieve high performance, the turbomachine has a small, high-pressure body, making it susceptible to various stresses such as gravitational loads, aircraft maneuvers, and axial moments.

[0006] A conventional turbomachine suspension with an upstream attachment on an upstream casing and a downstream attachment on a turbine casing or exhaust casing does not allow for optimization of the performance of the turbomachine assembly and aircraft cradle or pylon.

[0007] Another known solution, from document WO2022 / 245363, is to position a downstream suspension on the casing upstream of a high-pressure body (cantilevered high-pressure body solution). The bending moments induced by aerodynamic forces upstream of the turbomachine and the thrust will no longer be transmitted through the high-pressure body. Furthermore, this solution can create significant displacements between the pylon and the turbomachine at the high-pressure body not supported by suspensions, particularly when the turbomachine is subjected to acceleration factors. Under gravitational acceleration and aircraft maneuvers, this results in significant clearance wear and displacements between the turbomachine and the pylon.Furthermore, since the two suspension planes are close, it is difficult to achieve a good compromise of rigidity between the pylon and the upstream casing, which also leads to significant clearance consumption between the turbomachine and the pylon under axial moment loads. NVE TO PRESENTATION

[0008] One aim of the invention is to provide an aircraft assembly comprising a turbomachine, a cradle and a system for attaching the turbomachine to the cradle which allows for a compromise in attachment that limits the consumption of play in the high-pressure body.

[0009] To this end, the invention provides an assembly for an aircraft comprising a turbomachine, a cradle including an upstream frame and a system for attaching the turbomachine to the cradle, the turbomachine extending along a longitudinal axis oriented in a direction of a flow generated by the turbomachine, the turbomachine comprising, along the longitudinal axis, a propeller extending in a plane P orthogonal to the longitudinal axis, an upstream casing, an intermediate casing, a turbine casing and an exhaust casing, the attachment system comprising upstream attachment means for the turbomachine to the upstream frame of the cradle fixed at the level of the upstream casing of the turbomachine, intermediate attachment means for the turbomachine to the cradle fixed at the level of the intermediate casing of the turbomachine and rear attachment means for the turbomachine to the cradle fixed at the level of one of the turbine and exhaust casings of the turbomachine,wherein the upstream fastening means comprise a series of four coupling means from the upstream housing to the upstream cradle frame extending towards the propeller from the upstream frame and arranged such that each resultant of the recovery force of the coupling means has a direction intersecting the longitudinal axis at the level of the plane P of the propeller, and wherein either the intermediate fastening means comprise flexible attachment means and the rear fastening means comprise rigid fastening means, or the intermediate fastening means comprise rigid attachment means and the rear fastening means comprise flexible fastening means.

[0010] Advantageously, but optionally, the assembly according to the invention has at least one of the following technical characteristics: - each coupling means comprises a ball-and-socket connecting rod extending along the direction of the resultant of the associated recovery force; - the coupling means are equally distributed over a circumference of the upstream casing; - the coupling means are equally distributed over an upper half-circumference of the upstream casing; - the flexible fastening means include connecting rods with flexible pads or springs or deflection limiters with stops; - the rigid fixing means include ball-to-ball joint connecting rods; - the intermediate fixing means are fixed to the upstream frame of the cradle; - the flexible attachment means comprise supports including flexible pads or springs or ball-to-ball links mounted in series with flexible pads mounted in series; - the rigid attachment means include ball-to-ball joints; and, - the ball-to-ball joints are fixed to the cradle at the same attachment points to said cradle as part of the ball-to-ball joints of the coupling means of the upstream attachment means. BRIEF DESCRIPTION OF THE FIGURES

[0011] Other features and advantages of the invention will become apparent from the following description of an embodiment of the invention. See the attached drawings.

[0012] [Fig. 1] is a schematic three-dimensional view of a first embodiment of an aircraft assembly comprising a turbomachine, a cradle, and a system for connecting the turbomachine to the cradle according to the invention; and,

[0013] [Fig.2] is a schematic three-dimensional view of a second embodiment of an aircraft assembly comprising a turbomachine, a cradle and a turbomachine-to-cradle connection system according to the invention.

[0014] For clarity, identical or similar elements are identified by identical reference symbols across all figures. DETAILED DESCRIPTION OF A METHOD OF IMPLEMENTATION

[0015] With reference to figure 1, we will describe a first embodiment of an assembly according to the invention.

[0016] This first embodiment of an assembly according to the invention comprises a turbomachine 1, a cradle 2, and a fastening system 245, 25, 270 for attaching the turbomachine 1 to the cradle 2. As is known per se, the cradle 2 is generally itself attached to an aircraft wing. The turbomachine 1 comprises, in the direction of the flow, a propeller 3, rotating in a plane P, an upstream casing 4, an intermediate casing 5, a turbine casing 6, and an exhaust casing 7. The turbomachine 1 extends along a longitudinal axis XX, the plane P being perpendicular to the longitudinal axis XX. It should be noted that generally the turbine casing 6 (also called "Turbine Vane Frame" according to Anglo-Saxon terminology) is equipped with arms forming stator blades, and the exhaust casing 7 (also called "Turbine Rear Frame" according to Anglo-Saxon terminology) is the last casing of the turbomachine 1.

[0017] The cradle 2 extends parallel to the longitudinal axis XX and is generally located above the turbomachine 1. Here, it includes an upstream frame 21 in the shape of an arch, partially surrounding the turbomachine 1, generally at the level of the intermediate casing 5.

[0018] The fixing system 245,25,270 here includes upstream fixing means 245 of the turbomachine 1 to the upstream frame 21 of the cradle 2 fixed at the upstream casing 4 of the turbomachine 1, intermediate fixing means 25 of the turbomachine 1 to the cradle 2 fixed at the intermediate casing 5 of the turbomachine 1 and rear fixing means 270 of the turbomachine 1 to the cradle 2 fixed at one of the turbine casings 6 and exhaust casings 7 of the turbomachine 1.

[0019] The upstream fixing means comprise, here, a series of four coupling means 245 of the upstream casing 4 to the upstream frame 21 cradle 2 extending towards the propeller 3 from the upstream frame 21 and arranged so that each resultant of the recovery force of the coupling means 245 has a direction D intersecting the longitudinal axis XX at the level of the plane P of the propeller 3. Each coupling means 245 comprises a ball-and-socket connecting rod extending, along the convergent direction D of the resultant associated recovery force, between the upstream casing 4 and the upstream frame 21 of the cradle 2. The series of four coupling means 245 can be equally distributed over a circumference or a periphery of the upstream casing 4, or even over an upper half-circumference of the upstream casing 4. This allows for optimal handling of axial moment forces without transmission of these to the high-pressure body of the turbomachine 1, as well as a motor torque.

[0020] The intermediate fastening means include flexible attachment means 25, here two in number. The flexible attachment means 25 comprise supports with flexible pads. Alternatively, the flexible attachment means 25 include springs or ball-and-socket connecting rods with flexible pads mounted in series. The flexible attachment means 25 limit the banana-like deflection of the middle of the turbomachine 1 under inertial loads. Here, the intermediate fastening means 25 are fixed to the upstream frame 21 of the cradle 2.

[0021] In the preceding and subsequent descriptions, "flexible" means an element that allows at least one degree of freedom within a predetermined range, with or without reduced force transmission compared to a rigid connecting element between the two parts it joins. Similarly, a flexible fastener or attachment means a fastener or attachment that allows at least one degree of freedom within a predetermined range with reduced force transmission compared to a rigid fastener or attachment, thus providing localized relief.

[0022] The rear mounting means here comprise two rigid mounting means 270. Each rigid mounting means 270 has an inclined ball-and-socket joint. The rigid mounting means 270 allow the vertical and lateral forces and the engine torque downstream of the turbomachine 1 to be absorbed, and provide secure support for the high-pressure body under operating loads.

[0023] In the context of the invention, a rigid element or fixing is defined as an element or fixing which allows forces to be transmitted in at least one direction, in particular vertical and / or lateral and / or torque forces in order to ensure their absorption.

[0024] With reference to figure 2, we will describe a second embodiment of an assembly according to the invention.

[0025] This second embodiment differs from the first embodiment previously described in that the intermediate fastening means include rigid attachment means 256 and the rear fastening means include flexible fastening means 27.

[0026] The rigid attachment means comprise a series of two ball-joint connecting rods 256. Here, the ball-joint connecting rods 256 are fixed to the upstream frame 21 of the cradle 2. Alternatively, the ball-joint connecting rods 256 are fixed to the cradle 2 at the same attachment points on said cradle 2 as some of the ball-joint connecting rods 245 of the coupling means of the upstream attachment means, in particular the two upper ball-joint connecting rods 245. The rigid attachment means allow for the absorption of lateral vertical forces and a driving torque.

[0027] Each flexible mounting means 27 comprises a ball joint and a flexible mount connected in series with said ball joint. Alternatively, the flexible mounting means 27 comprises a spring or a deflection limiter with stops allowing the high-pressure body to move to a certain extent without transmitting force. The flexible mounting means 27 limit the deflection of the high-pressure body of the turbomachine 1 under inertial loads.

[0028] The implementation of one of the previously described embodiments of an assembly according to the invention has the advantage of being the least hyperstatic compared to traditional assemblies and of allowing effective protection of the high-pressure body from axial moment forces while preventing it from being cantilevered and minimizing the mass of the attachment of the turbomachine 1.

[0029] This allows control of the high-pressure body clearances to ensure its performance / operability in a new engine and a removal time compatible with short and medium-haul operation of the aircraft thus equipped.

[0030] Naturally, the invention described above is by way of example. It is understood that a person skilled in the art is capable of carrying out different embodiments of the invention without departing from its scope.

[0031] It is emphasized that all features, as they are apparent to a person skilled in the art from this description, the drawings and the attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances render such combinations impossible or meaningless.

Claims

DEMANDS 1. Assembly for an aircraft comprising a turbomachine (1), a cradle (2) including an upstream frame (21) and a fastening system (245, 25, 256, 27, 270) of the turbomachine (1) to the cradle (2), the turbomachine extending along a longitudinal axis (XX) oriented in a direction of a flow generated by the turbomachine, the turbomachine comprising, along the longitudinal axis (XX), a propeller (3) extending in a plane P orthogonal to the longitudinal axis (XX), an upstream casing (4), an intermediate casing (5), a turbine casing (6) and an exhaust casing (7), the fastening system including upstream fastening means of the turbomachine to the upstream frame of the cradle fixed at the level of the upstream casing (4) of the turbomachine,intermediate fixing means of the turbomachine to the cradle fixed at the level of the intermediate casing (5) of the turbomachine and rear fixing means of the turbomachine to the cradle fixed at the level of one of the turbine casings (6) and exhaust casings (7) of the turbomachine, wherein the upstream fixing means comprise a series of four coupling means (245) of the upstream casing to the upstream cradle frame extending towards the propeller from the upstream frame and arranged such that each resultant of the recovery force of the coupling means has a direction (D) intersecting the longitudinal axis (XX) at the level of the plane P of the propeller, and wherein either the intermediate fixing means comprise flexible attachment means (25) and the rear fixing means comprise rigid fixing means (270),either the intermediate fastening means comprise rigid attachment means (256) and the rear fastening means comprise flexible fastening means (27).

2. Assembly according to claim 1, wherein each coupling means comprises a ball-joint connecting rod (245) extending along the direction (D) of the resultant of the associated recovery force.

3. Assembly according to any one of claims 1 to 2, wherein the coupling means are evenly distributed over a circumference of the upstream housing.

4. Assembly according to any one of claims 1 to 2, wherein the coupling means are equally distributed over an upper half-circumference of the upstream housing.

5. Assembly according to any one of claims 1 to 4, wherein the flexible fastening means (27) comprise connecting rods with flexible pads or springs or deflection limiters with stops.

6. Assembly according to any one of claims 1 to 4, wherein the rigid fastening means comprise ball-to-ball connecting rods (270).

7. Assembly according to any one of claims 1 to 6, wherein the intermediate fastening means are fixed to the upstream frame of the cradle.

8. Assembly according to any one of claims 1 to 7, wherein the flexible attachment means (25) comprise supports including flexible pads or springs or ball-to-ball links mounted in series with flexible pads mounted in series.

9. Assembly according to any one of claims 1 to 7, wherein the rigid attachment means comprise ball-to-ball connecting rods (256).

10. Assembly according to claim 9, wherein the ball-to-ball joints (256) are fixed to the cradle at the same fixing points to said cradle as a portion of the ball-to-ball joints (245) of the coupling means of the upstream fixing means.

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