SET COMPRISING AN AIRCRAFT TURBOMACHINE AND ITS MOUNTING PYLON

Abstract

The invention relates to an assembly (1) comprising an aircraft turbomachine (2), a pylon (40) for attaching the turbomachine to an element of the aircraft, and a system for suspending the turbomachine from the pylon, the turbomachine having a longitudinal axis (X) and comprising from upstream to downstream, in the direction of gas flow: > a fan casing (11) centered on the longitudinal axis (X) and comprising a first axial end (12) located upstream of the fan (10), and > a gas generator (16) configured to receive an air flow generated by a fan, the pylon (40) being of generally elongated shape along said longitudinal axis (X) and being capable of being fixed to the element of the aircraft, characterized in that the suspension system comprises at least one connecting rod (30, 30a, 30b) for absorbing stick force, a first end (31, 31a, 31b) is connected to a fixing point (11a,11b) of the fan casing (11) located on the first axial end or on an upstream portion of the fan casing, and of which an opposite second end (32, 32a, 32b) is connected to the pylon. Figure for the abstract: Fig. 1a,

Description

Title of the invention: ASSEMBLY COMPRISING AN AIRCRAFT TURBOMACHINE AND ITS PYLON HANGING Technical field of the invention

[0001] The present invention relates to an assembly comprising an aircraft turbomachine and its attachment pylon. Technical background

[0002] An aircraft turbomachine comprises a gas generator which conventionally comprises, from upstream to downstream, with reference to the flow of gases in the turbomachine, at least one compressor, a combustion chamber and at least one turbine. In the case of a twin-spool turbojet engine, respectively low pressure and high pressure, the gas generator successively comprises a low pressure compressor, a high pressure compressor, the combustion chamber, the high pressure turbine and the low pressure turbine. The gas generator comprises a primary annular flow path for a primary gas flow which passes through the compressors, the combustion chamber and the turbines.

[0003] The rotor of the high pressure compressor is connected to the rotor of the high pressure turbine by a high pressure shaft. The rotor of the low pressure compressor is connected to the rotor of the low pressure turbine by a low pressure shaft which passes through the high pressure shaft and which rotates a propulsion blade / propeller generally located upstream of the gas generator.

[0004] When this blade / propeller is shrouded and therefore surrounded by an annular casing, this blade / propeller is called a fan and generates an air flow which flows around the gas generator. This annular casing, called a fan casing, is radially external to the gas generator relative to a longitudinal axis of the turbomachine and defines with the gas generator a secondary flow vein for a secondary flow.

[0005] The fan casing comprises a fan casing and an inlet casing, located downstream of the fan casing, and which connects the fan casing to the gas generator. The inlet casing typically comprises a hub centered on the longitudinal axis of the turbomachine and an annular outer shroud arranged coaxially around the hub. The annular outer shroud is fixed to the inlet casing, downstream of the latter, and defines with the hub a portion of the secondary vein.

[0006] The turbomachine further comprises an inter-compressor casing which extends between two successive compressors of the gas generator or which surrounds all or part of the or gas generator compressors, for example between the low pressure and high pressure compressors.

[0007] The turbomachine further comprises a nacelle located around the fan and the gas generator. The nacelle is annular and extends around the longitudinal axis of the turbomachine.

[0008] The turbomachine is attached to an element of the aircraft, such as a wing or a fuselage, by means of a suspension pylon, also called a mast, and a suspension system. The pylon generally has an elongated general shape and comprises a beam which extends parallel to the longitudinal axis of the turbomachine. In the case where the turbomachine is attached under a wing of the aircraft, the pylon is generally located at 12 o'clock (12 o'clock) by analogy with the dial of a clock.

[0009] The suspension system generally comprises a plurality of upstream and / or downstream connecting elements for fixing and suspending the pylon from the turbomachine. These connecting elements have the role of absorbing the forces generated in the turbomachine along different axes, as well as the moments generated with respect to these axes and are generally connected to casings of the turbomachine.

[0010] The turbomachine is, in particular, subjected to thrust forces corresponding to a moment generated by the axial forces. Indeed, in operation, the gas generator ensures a transmission of forces between the upstream and downstream fixing points to the pylon which is the cause of deformations of the gas generator and modifications of the clearances between the rotors and the stators of the gas generator.

[0011] The turbomachine is also subjected to a moment generated by the asymmetry of axial forces on the fan blades, and to forces originating from the capture of air by the turbomachine, called sleeve forces. These sleeve forces are typically distributed between the hub of the inlet casing, located upstream of the turbomachine, and a turbine casing or exhaust casing, located downstream of the turbomachine. Thus, when a force is applied upstream of the turbomachine, this force is capable of passing to downstream of the turbomachine, and can therefore be the cause of a bending of the gas generator, and a distortion of the high-pressure body.

[0012] To absorb these sleeve forces, one solution would be to stiffen the turbomachine casings, which would prevent bending of the gas generator. Another solution would be to transfer the sleeve forces into the turbomachine nacelle. However, this solution would not be entirely satisfactory because it would raise issues regarding accessibility and maintenance of the turbomachine. Incidentally, the performance and operability of the turbomachine could be affected.

[0013] The present invention provides a solution to at least part of the problems mentioned above. Summary of the invention

[0014] The invention proposes an assembly comprising an aircraft turbomachine, a pylon for attaching the turbomachine to an element of the aircraft, and a system for suspending the turbomachine from the pylon, the turbomachine having a longitudinal axis and comprising from upstream to downstream, in the direction of flow of the gases in operation: > a fan casing centered on the longitudinal axis around a fan of the turbomachine, said fan casing comprising a first axial end located upstream of the fan, and a second axial end located downstream of the fan, and > a gas generator configured to receive an air flow generated by the blower, the gas generator comprising a primary flow vein of a primary flow through at least one compressor, a combustion chamber and at least one turbine, the blower casing being radially external to the gas generator relative to the longitudinal axis and defining with the gas generator a secondary flow vein of a secondary flow, the pylon being of generally elongated shape along said longitudinal axis and being capable of being fixed to the element of the aircraft, the suspension system comprising elements connecting the pylon to the turbomachine, characterized in that the suspension system comprises at least one stick force recovery rod, a first end of which is connected to a fan casing attachment point located on the first axial end or on an upstream portion of the fan casing, and a second opposite end of which is connected to the pylon.

[0015] The assembly according to the invention makes it possible to solve at least some of the problems of the prior art. Indeed, the stick force absorption connecting rod connects the attachment point of the fan casing, which is located on the first axial end or on the upstream portion of the fan casing, and the pylon, which makes it possible to absorb the stick forces without having to stiffen the casings of the turbomachine and without having to pass through the nacelle of the turbomachine. When a force is applied upstream of the turbomachine, it does not pass through the gas generator, in particular from upstream to downstream of the turbomachine, but passes directly to the pylon. Thus, the risk of bending of the gas generator and distortion, for example of its high-pressure body, is limited.

[0016] According to different characteristics of the invention which can be taken together or separately: the pylon is connected to the first end of the fan casing by a single connecting rod which is located in a plane passing through the longitudinal axis and through the pylon; the pylon is connected to the first axial end of the fan casing by two adjacent connecting rods which are arranged symmetrically with respect to a plane passing through the longitudinal axis, between the connecting rods, and through the pylon; the connecting rods form an angle between them of between 2° and 50°, and preferably between 20° and 40°; the second end of the or each connecting rod is directly connected to the pylon; the second end of the or each connecting rod is connected to an intermediate structure which is fixed to both the pylon and the fan casing; the fan casing comprises a fan casing and an inlet casing located downstream of the fan casing, the attachment point being located on a downstream axial end of the fan casing or an upstream axial end of the inlet casing; the first and second ends of the or each connecting rod comprise ball joints; the pylon comprises an upstream end located in a plane perpendicular to the longitudinal axis and located upstream of the combustion chamber; the upstream end of the pylon is located upstream of the second axial end of the fan casing; the connecting elements comprise thrust recovery connecting rods, first ends of which are connected to the gas generator, upstream of the combustion chamber of the gas generator, and second opposite ends of which are connected to the pylon; the first ends of the thrust recovery connecting rods are connected to the input casing, and in particular to a hub of this input casing; the inlet casing having arms which extend radially outwardly from the hub and pass through the secondary vein to rigidly connect the gas generator to the fan casing; the connecting elements comprise a suspension structure fixed to the gas generator and to the pylon, downstream of the combustion chamber of the gas generator; the suspension structure is attached to an exhaust casing of the turbomachine, which is located downstream of the turbine(s) of the gas generator; the second ends of the thrust recovery connecting rods are connected to the pylon via the suspension structure; the pylon is located at 12 o'clock by analogy with the face of a clock; the pylon is located at 3 o'clock or 9 o'clock by analogy with the face of a clock; - the pylon is inclined by ±10 degrees. Brief description of the figures

[0017] Other objects, characteristics and advantages of the invention will appear more clearly in the description which follows, made with reference to the appended figures, in which:

[0018] - [Fig.1a] is a schematic perspective view of an assembly comprising a aircraft turbomachine and its attachment pylon according to a first embodiment of the invention;

[0019] - [Fig.lb] is a schematic perspective view of an assembly comprising a aircraft turbomachine and its attachment pylon according to a second embodiment of the invention;

[0020] - [Fig.2a] is a schematic perspective view of an assembly such as that of the [Fig.1a] according to a third embodiment of the invention;

[0021] - [Fig.2b] is a schematic perspective view of an assembly such as that of the [Fig.lb] according to a fourth embodiment of the invention;

[0022] - [Fig.3] is a schematic side view of an assembly according to a variant of the rea lization of the whole [Fig.la];

[0023] - [Fig.4] is a schematic view of an intermediate structure for an assembly according to the invention;

[0024] - [Fig.5] is a very schematic view of an aircraft turbomachine and shows fixing and suspension points to a suspension pylon, according to one embodiment of the invention. Detailed description of the invention

[0025] [Fig. 1a] illustrates an assembly 1 according to a first embodiment of the present invention. This assembly 1 comprises a turbomachine 2 for an aircraft, a pylon 40 for attaching the turbomachine 2 to an element of the aircraft, and a system for suspending the turbomachine 2 from the pylon 40. The turbomachine extends around and along a longitudinal axis X. The longitudinal axis X is oriented from upstream to downstream of the turbomachine 2.

[0026] In the present application, the terms "axial", "axially", "radial" and "radially" are defined with respect to the longitudinal axis X.

[0027] The terms “upstream” and “downstream” are defined in relation to the direction of circulation of the gases in the turbomachine 2 along the longitudinal axis X. In the present application, the elements of the turbomachine located upstream of the combustion chamber are upstream of the turbomachine, while the elements of the turbomachine located downstream of the combustion chamber are downstream of the turbomachine.

[0028] In the present description, when the term "connecting rod" is not followed by the expressions "stick force recovery", "thrust recovery", we will consider by default that it is a stick force recovery connecting rod.

[0029] The turbomachine 2 is here a double-flow, double-spool turbojet. It comprises from upstream to downstream, in the direction of flow of the gases in operation, a fan 10 and a gas generator 16. Although this is not visible in [Fig.1a], the gas generator 16 comprises from upstream to downstream, at least one compressor such as a low-pressure compressor 17 and a high-pressure compressor 18, a combustion chamber 19, at least one turbine such as a high-pressure turbine 20 and a low-pressure turbine 21. These different elements of the turbomachine 2 are illustrated very schematically in [Fig.5].

[0030] The blower 10 allows the suction of an air flow F dividing into a first air flow, called primary flow F1, and into a second air flow, called secondary flow F2. The gas generator 16 defines a main annular vein VI for the flow of the primary flow FL. The gas generator 16 is surrounded by a secondary annular vein V2 for the flow of the secondary flow F2.

[0031] The primary flow F1 is compressed within the low pressure compressor 17 then the high pressure compressor 18. The compressed air of the primary flow is then mixed with a fuel and burned within the combustion chamber 19. The gases formed by the combustion pass through the high pressure 20 and low pressure 21 turbines. The gases finally escape through a nozzle whose section allows the acceleration of these gases to generate propulsion (part of the thrust, -20%).

[0032] The rotor of the high pressure compressor 18 is connected to the rotor of the high pressure turbine 20 by a high pressure shaft 3, and the rotor of the low pressure compressor 17 is connected to the rotor of the low pressure turbine 21 by a low pressure shaft 4 which passes through the high pressure shaft 3 and which drives in rotation a propulsion blade / propeller located upstream of the gas generator 16 and which is surrounded by an annular casing called fan casing 11.

[0033] The fan casing 11 is centered on the longitudinal axis X around a fan 10 of the turbomachine. It defines, with the gas generator 16, the secondary flow stream V2 of the secondary flow F2. The fan casing 11 may comprise a fan casing 29 and an inlet casing 25 or, alternatively, be formed from a single piece. In the present application, the fan casing 11 comprises a first axial end 12 located upstream of the fan 10, such as a flange for fixing the air inlet, and a second axial end 13 located downstream of the fan 10, ensuring, for example, the connection with the thrust reverser or the nacelle cowls. The first axial end 12 is located at the fan casing 29 while the second end 13 is located at the inlet casing 25. Incidentally, the first axial end 12 is therefore further from the gas generator 16 than the second axial end 13.

[0034] In other words, the end 12 is located in a first plane P12 which is perpendicular to the axis X and which is located upstream of the fan blades 14. The end 13 is located in a second plane P13 which is perpendicular to the axis X and which is located downstream of the fan blades 14.

[0035] The fan casing 11 is connected to the gas generator 16 by the inlet casing 25. The latter comprises a central hub 26 and a series of radial arms 15 connecting the hub 26 to the fan casing 11.

[0036] The turbomachine 2 comprises an inter-compressor casing 24 which extends between the low-pressure 17 and high-pressure 18 compressors. It also comprises an inter-turbine casing 27 arranged axially between the low-pressure and high-pressure turbines 21, 20. The turbomachine 2 further comprises bearing supports 28 which serve as support for shaft guide bearings.

[0037] The turbomachine 2 is attached to an element of the aircraft, such as a wing or a fuselage, by means of the attachment pylon 40. The pylon 40 generally has a general elongated shape along an elongation axis B of the pylon and is capable of being attached to an element of the aircraft. The elongation axis B is parallel to the longitudinal axis X of the turbomachine. In the case where the turbomachine 2 is attached under a wing of the aircraft, the pylon 40 is located at 12 o'clock (12 hours) by analogy with the dial of a clock. However, the pylon 40 may be located at 9 o'clock (9 hours) when it is attached to the fuselage of the aircraft. Other design variants are conceivable depending on the type of turbomachine. According to one implementation, the X and B axes are in the same vertical plane when pylon 40 is at 12 o'clock.The pylons can also be inclined by a few degrees, preferably ± 10°, relative to the vertical plane (perpendicular / dihedral to the wing) or horizontal (improving the flow around the fuselage).

[0038] [Fig.1a] also illustrates the orthonormal XYZ reference frame where the X axis is oriented from upstream to downstream of the turbomachine 2, the Z axis is oriented vertically upwards and the Y axis is oriented to one side.

[0039] In the present application, the term "force" means the force which is transmitted with the same direction as an axis, X, Y or Z, taken as a reference. The axial, transverse and vertical forces are respectively the forces transmitted with the same direction as the X axis, the Y axis and the Z axis taken as a reference. The axial forces which are exerted on the elements of the aircraft result from a tensile type stress while the vertical forces exerted on the elements of the aircraft result from a compressive type stress. That being said, in addition to the axial, transverse and vertical forces, moments are also exerted on the elements of the aircraft. The elements of the aircraft are subjected to axial, transverse and vertical moments. acting respectively along the X, Y and Z axes.

[0040] When an element of the suspension system, for example a member for attaching the pylon 40 to the turbomachine 2, absorbs forces along the X axis, this means that this attachment member blocks any movement along the X axis of the parts to which it is connected. This absorption is called axial absorption. Similarly, when the attachment member absorbs forces along the Y or Z axis, this means that this attachment member blocks any movement along, respectively, the Y or Z axis of the parts to which it is connected. These absorptions are respectively called transverse and vertical absorptions. Similarly, when a member for attaching the pylon 40 to the turbomachine 2 absorbs moments Mx around the X axis, this means that this attachment member blocks any rotational movement of the parts to which it is connected around the X axis. This also applies to moments My and Mz, respectively, around the Y axis and the Z axis.

[0041] In the context of the invention, the suspension system comprises all of the elements which connect the turbomachine 2 to the pylon 40. These different elements of the suspension system are arranged and / or configured so as to absorb the forces in the three directions, namely an axial direction of axis X, a transverse direction of axis Z and a lateral direction of axis Y, or in some of these directions, as well as the moments Mx, My and Mz around these three directions respectively, or around some of these directions.

[0042] To recover the sleeve forces, the present invention proposes to carry out an axial recovery, that is to say along the X axis. It can be recalled, at this stage, that the sleeve forces come from the moment generated by the asymmetry of axial forces on the fan blades, and from the forces linked to the capture of air in particular when the propulsion unit is in incidence. The torque resulting from the balance of the pressures on the inlet sleeve in incidence is composed mainly of moment components My and Mz but also of the sleeve forces. They are generally distributed between the hub 26 of the inlet casing 25 and an exhaust casing 22 of the turbomachine.

[0043] In this respect, according to the invention and as illustrated in the figures, the suspension system comprises at least one connecting rod 30, 30a, 30b for absorbing the stick force, a first end 31, 31a, 31b of which is connected to a fixing point 11a, 11b of the fan casing 11 located on the first axial end 12 or on an upstream portion of the fan casing, and a second end 32, 32a, 32b of which opposite the first end 31, 31a, 31b is connected to the pylon 40. The or each connecting rod 30, 30a, 30b is functional by default since it provides a fixing and suspension function by default when it is not degraded or broken.

[0044] The or each connecting rod 30, 30a, 30b makes it possible to take up the forces along the X axis, and therefore the traction / compression forces in the direction of the connecting rod. Thus, the system of suspension of the assembly 1 according to the invention makes it possible to transmit the handle forces through the pylon 40 instead of transmitting these handle forces through the gas generator 16. The risk of bending of the gas generator 16 and distortion of the high pressure body is therefore non-existent or very greatly reduced.

[0045] Furthermore, the effectiveness of the invention in absorbing the stick forces also comes from the distance separating the first end 31, 31a, 31b and the second end 32, 32a, 32b of the or each connecting rod 30, 30a, 30b. Indeed, the first 31, 31a, 31b and the second 32, 32a, 32b ends are separated by a distance at least equal to the distance between the first axial end 12 and the second axial end 13 of the fan casing 11 (axial distance between the planes P12 and P13) or between the upstream portion of the fan casing and the second axial end, which makes it possible to effectively absorb the stick forces by a lever effect. In this regard, and preferably, the upstream portion of the fan casing extends over a distance of at most 60% of a total length of the fan casing, and preferably at most 40% of the total length of the fan casing along the longitudinal axis X, from the first axial end 12.The fan case length is the dimension of the fan case along the longitudinal axis X.

[0046] In a first embodiment of the assembly 1 illustrated in [Fig.1a], the pylon 40 is connected to the first axial end 12 of the fan casing by a single connecting rod 30 which is located in a plane PI passing through the longitudinal axis X and through the pylon 40. In this first embodiment, the attachment point 11a of the fan casing 11 is therefore located on the first axial end 12 of the fan casing. The connecting rod 30 is said to be axial since it extends mainly in a plane, here PI, passing through the longitudinal axis X of the turbomachine 2. Thus, the first 31 and second 32 ends of the connecting rod 30 are located in the plane PL. Preferably, the first 31 and second ends 32 of the connecting rod 30 comprise ball joints. These are conventional ball joints allowing each of the first 31 and second 32 ends to swivel freely.

[0047] In the particular case illustrated in [Fig.1a], the plane PI extends along the directions X, Z. The connecting rod 30 creates a support directly on the first axial end 12, and therefore at the point of application of the force. The connecting rod 30 therefore makes it possible to take up the forces along the X axis, and at least part of the forces along the Z axis. In the absence of the connecting rod 30, it would be necessary to take up the moment generated on the gas generator 16 by two vertical reactions, a first on the inlet casing 25 and a second on the exhaust casing 22. However, this would induce a moment My in the downstream part of the turbomachine 2, in addition to generating the bending of the turbomachine and the degradation of the clearances. The connecting rod 30 makes it possible to directly make a connection between the first axial end 12 and the pylon 40. Thus, the assembly 1 makes it possible to make transmit the maximum force into the pylon 40 instead of having them transmit it into the gas generator 16 as in the prior art. Consequently, this makes it possible to reduce the vertical forces in the plane of the exhaust casing 22 and therefore the moment My in the gas generator 16. The recovery of the sleeve forces is therefore carried out upstream of the combustion chamber 19 and therefore upstream of the turbomachine 2.

[0048] Referring now to [Fig.lb], in the assembly 1 according to the second embodiment, the pylon 40 is connected to the first axial end 12 of the fan casing by two adjacent connecting rods 30a, 30b which are arranged symmetrically with respect to a plane PI' passing through the longitudinal axis X, between the connecting rods 30a, 30b, and by the pylon 40. In this second embodiment, attachment points 11a and 11b of the fan casing 11 are located on the first axial end 12 of the fan casing. Thus, a first connecting rod 30a and a second connecting rod 30b are arranged in planes symmetrical with respect to the plane PI'. Like the single connecting rod 30 of the assembly 1 according to the first embodiment ([Fig.1a]), the connecting rods 30a, 30b are axial since they are arranged symmetrically with respect to a plane PI' passing through the longitudinal axis X of the turbomachine 2.In this arrangement, the sum of the contributions to the recovery of forces, along the X axis, made by the first connecting rod 30a and the second connecting rod 30b generates a recovery of axial forces along the X axis direction.

[0049] More precisely, the connecting rods 30a, 30b make it possible to absorb forces having transverse components, i.e. along the Y axis, and vertical components, i.e. along the Z axis. In addition, the first 30a and second 30b connecting rods make it possible to absorb the moments Mz around the Z axis. The fact, as indicated above, that the connecting rods 30a, 30b can absorb the moment Mz around the Z axis comes from their symmetrical arrangement with respect to the plane PI', in particular in two different planes. The connecting rods 30a and 30b therefore make it possible to prevent any axial movement of the fan casing 11 along the X axis and any rotational movement around the vertical axis Z. The absorption of the sleeve forces is carried out, in this embodiment also, upstream of the combustion chamber 19 and therefore upstream of the turbomachine 2.

[0050] Preferably, the first 31a, 31b and second 32a, 32b ends of the connecting rods 30a, 30b comprise ball joints allowing each of the first 31a, 31b and second 32a, 32b ends to rotate freely.

[0051] According to a particularly advantageous implementation, the connecting rods 30a, 30b form an angle between them of between 2° and 50°. The first and second connecting rods 30a, 30b are therefore not parallel to each other. In addition, this also means that the first and second connecting rods 30a, 30b are not parallel to the plane PI' passing through the longitudinal axis X of the turbomachine 2 since the connecting rods 30a and 30b are sy metric with respect to this plane PI'. The angle formed between the connecting rods 30a and 30b is advantageously oriented from downstream to upstream, which means that the second ends 32a, 32b of the connecting rods are closer to each other than the first ends 31a, 31b of the connecting rods.

[0052] For example, when the connecting rods 30a, 30b form an angle of 2° between them, this implies that each of them makes an angle of 1° with the plane PI'. If the connecting rods 30a, 30b form an angle of 50° between them, this implies that each of said connecting rods 30a, 30b makes an angle of 25° with the plane PI'. With regard to this last example, it should be specified that it is preferable for the angle formed by the connecting rods 30a, 30b between them not to exceed 50° in order not to generate contact between the connecting rods 30a, 30b and the fan casing 11 and not to generate transverse and vertical forces in the plane YZ which would in turn generate a moment Mx.

[0053] Advantageously, the connecting rods 30a, 30b form an angle between them of between 20 and 40°, which makes it possible to take up the moment My around the transverse axis Y and the moment Mz around the vertical axis efficiently, and therefore makes it possible to take up the sleeve forces efficiently in a configuration with two connecting rods 30a, 30b.

[0054] The second end 32, 32a, 32b of the or each connecting rod 30, 30a, 30b is directly connected to the pylon 40. Preferably, the second end 32, 32a, 32b of the or each connecting rod 30, 30a, 30b is directly connected to the center of the pylon 40. However, as will be better understood below, the second end 32, 32a, 32b of the or each connecting rod 30, 30a, 30b may not be directly connected to the pylon 40. Indeed, the second end 32, 32a, 32b of the or each connecting rod 30, 30a, 30b may be connected to an intermediate structure 50. When the second end 32, 32a, 32b is directly connected to the pylon 40, the second end 32, 32a, 32b of the or each connecting rod 30, 30a, 30b may be connected to an intermediate structure 50. 40, this makes it possible to dispense with the use of this intermediate structure 50. That being said, in practice, as this intermediate structure 50 makes it possible to attach the fan casing 11 to the pylon 40, the assembly 1 necessarily includes such an intermediate structure 50.The advantage of directly connecting the second end 32, 32a, 32b to the pylon 40 therefore lies more in the use of a simple intermediate structure 50.

[0055] [Fig. 4] illustrates an intermediate structure 50 that could be used in the context of the invention. The intermediate structure 50 comprises at least a first fixing element 51 to the pylon 40 and a second fixing element 52 to the fan casing 11. The second fixing element 52 may have a generally curved shape. It may comprise a support 52 of curved shape matching the contours of the fan casing 11. The support 52 is configured to allow the mounting of lateral connecting rods 56a, 56b and a central connecting rod 57.

[0056] In a third embodiment of the assembly 1 illustrated in [Fig.2a], the pylon 40 is connected to a fixing point 11a of the fan casing 11 located in the portion upstream of the fan casing by a connecting rod 30. The connecting rod 30 creates a support at the attachment point 11a, and therefore between the first axial end 12 and the second axial end 13. Under these conditions, the connecting rod 30 creates a support near the point of application of the force, which makes it possible to take up the forces along the X axis, and at least part of the forces along the Z axis. Thus, the assembly 1 makes it possible to transmit part of the forces in the pylon 40 instead of transmitting them in the gas generator 16. Consequently, this makes it possible to reduce the vertical forces in the plane of the exhaust casing 22 and therefore the moment My in the gas generator 16. As in the first and second embodiments, the connecting rod 30 may comprise ball joints.

[0057] That being said, it is preferable for the attachment point 11a to be located at a distance of at most 40% of the length of the fan casing from the first axial end 12 of the fan casing. Indeed, the closer the attachment point 11a is to the first axial end 12, the more effective the absorption of axial forces along the X axis is.

[0058] In a particularly advantageous manner, the fixing point 11a may be located on a downstream axial end 29b of the fan casing 29, opposite its upstream end 29a. Alternatively, the fixing point 11a may be located on an upstream axial end 25a of the inlet casing 25, opposite a downstream end 25b of the inlet casing. In either case, the fixing point 11a is located on the upstream portion of the fan casing 11. The downstream axial end 29b of the fan casing 29 and the upstream axial end 25a of the inlet casing are therefore preferably at a distance of at most 60% of the length of the fan casing from the first axial end 12 of the fan casing.

[0059] In a fourth embodiment of the assembly 1 illustrated in [Fig.2b], the pylon 40 is connected to fixing points 11a, 11b of the fan casing 11 located on the upstream portion of the fan casing by two adjacent connecting rods 30a, 30b which are arranged symmetrically with respect to a plane PI' passing through the longitudinal axis X, between the connecting rods 30a, 30b, and by the pylon 40. The connecting rods 30a, 30b make it possible to take up forces having transverse components and vertical components as well as the moments Mz around the axis Z. The connecting rods 30a and 30b therefore make it possible to prevent any axial movement of the fan casing 11 along the axis X and any rotational movement around the vertical axis Z.

[0060] As in the third embodiment, the attachment points 11a, 11b may be located at a distance of at most 60% of the length of the fan casing along the longitudinal axis X from the first axial end 12. However, it is preferable that the attachment points 11a, 11b are located at a distance of at most 40% of the length of the fan casing from the first axial end 12 of the fan casing. Indeed, the closer the fixing points 11a, 11b are to the first axial end 12, the more effective the absorption of axial forces along the X axis is. In practice, the fixing points 11a, 11b may be located on a downstream axial end 29b of the fan casing 29 or, alternatively, on an upstream axial end 25a of the inlet casing 25.

[0061] In the illustrated embodiments, the pylon 40 comprises an upstream end 42 located in a plane P2 perpendicular to the longitudinal axis X and located upstream of the combustion chamber 19, and preferably upstream of the second axial end 13 of the fan casing 11. Thus, whether the second end(s) 32, 32a, 32b are directly connected to the upstream end 42 of the pylon or to the intermediate structure 50, itself connected to the upstream end 42 of the pylon, the absorption of the lateral and vertical forces takes place in the plane P2, and therefore upstream of the gas generator 16.

[0062] The plane P2 does not necessarily need to be located upstream of the second axial end 13 of the fan casing 11. What is important is that it is located upstream of the combustion chamber 19 and that thus no sleeve force can pass through the combustion chamber.

[0063] As also visible in the attached figures, in addition to the rod(s) 30, 30a, 30b for absorbing the stick force, the suspension system may comprise thrust absorbing rods 45, first ends 47 of which are connected to the gas generator 16, upstream of the combustion chamber 19 of the gas generator, and second opposite ends 48 of which are connected to the pylon 40 or the intermediate structure 49. Like the rod(s) 30, 30a, 30b for absorbing the stick force, the thrust absorbing rods 45 are functional by default since they provide a fixing and suspension function by default when they are not damaged or broken.

[0064] In Figures 1a to 1b, the suspension system comprises two thrust recovery rods 45. They essentially allow axial forces to be absorbed, i.e. the forces generated along the X axis.

[0065] The thrust recovery rods 45 are arranged on each side of the plane PI or PI', as the case may be, in pairs. On each side, there is one of the thrust recovery rods 45. These thrust recovery rods 45 are, like the stick recovery rods 30, 30a, 30b, provided with ball joints. In [Fig. 3], the suspension system comprises two thrust recovery rods 45, each of them being located on either side of the plane PL

[0066] According to a preferred implementation, the first ends 47 of the thrust recovery connecting rods 45 are connected to the inlet casing 25 of the gas generator, and in particular to a hub 26 of the inlet casing. This inlet casing 25 comprises arms 15 which extend radially outwards from the hub 26 and cross the secondary vein V2 to rigidly connect the gas generator 16 to the fan casing 11. Thus, the thrust recovery connecting rods 45 are therefore connected to a fixed part of the gas generator, in this case the hub 26 of the inlet casing 25.

[0067] In this regard, in the illustrated embodiments, the pylon 40 is located at 12 o'clock by analogy with the dial of a clock.

[0068] According to a preferred implementation, the connecting elements further comprise a suspension structure 49 fixed to the gas generator 16 and to the pylon 40, this suspension structure being located downstream of the combustion chamber 19 of the gas generator. This suspension structure 49 performs the same function as the intermediate structure 50, described previously, by being located downstream of the combustion chamber 19 and therefore downstream of the turbomachine 2. The suspension structure 49 thus makes it possible to take up the transverse and vertical forces, that is to say the forces generated in the Y and Z axis directions.

[0069] According to a preferred implementation, the suspension structure 49 is fixed to an exhaust casing 22 of the turbomachine, which is located downstream of the turbine(s) 20, 21 of the gas generator. The exhaust casing 22, also called the turbine casing, is connected to the inlet casing 25 and aligned along the longitudinal axis X of the turbomachine with the inlet casing 25. Advantageously, the second ends 48 of the thrust recovery connecting rods 45 are connected directly to the pylon 40 or via the suspension structure 49.

[0070] The configurations shown in the cited figures are only possible examples, in no way limiting, of the invention which on the contrary encompasses the design variants within the reach of those skilled in the art. For example, the turbomachine 2 is not necessarily a double-flow double-spool turbomachine.

Claims

Claims

1. Assembly (1) comprising an aircraft turbomachine (2), a pylon (40) for attaching the turbomachine to an element of the aircraft, and a system for suspending the turbomachine from the pylon, the turbomachine (2) having a longitudinal axis (A) and comprising from upstream to downstream, in the direction of flow of the gases in operation: > a fan casing (11) centered on the longitudinal axis (A) around a fan (10) of the turbomachine, said fan casing (11) comprising a first axial end (12) located upstream of the fan (10), and a second axial end (13) located downstream of the fan, and > a gas generator (16) configured to receive an air flow generated by the fan, the gas generator (16) comprising a primary flow vein (VI) for the flow of a primary flow (Fl) through at least one compressor (17, 18), a combustion chamber (19) and at least one turbine (20, 21),the fan casing (11) being radially external to the gas generator (16) relative to the longitudinal axis (X) and defining with the gas generator (16) a secondary flow vein (V2) of a secondary flow (F2), the pylon (40) being of generally elongated shape along said longitudinal axis (X) and being capable of being fixed to the element of the aircraft, the suspension system comprising connecting elements (45, 49) of the pylon to the turbomachine, characterized in that the suspension system comprises at least one connecting rod (30, 30a, 30b) for absorbing stick force, a first end (31, 31a, 31b) of which is connected to a fixing point (11a, 11b) of the fan casing (11) located on the first axial end (12) or on an upstream portion of the fan casing (11), and a second end (32, 32a, 32b) opposite is connected to the pylon (40).,

2. An assembly according to claim 1, wherein the pylon (40) is connected to the first axial end (12) of the fan casing by a single connecting rod (30) which is located in a plane (PI) passing through the longitudinal axis (X) and through the pylon (40).

3. An assembly according to claim 1, wherein the pylon (40) is connected to the first axial end (12) of the fan casing by two adjacent connecting rods (30a, 30b) which are arranged symmetrically with respect to a plane (PE) passing through the longitudinal axis (X), between the connecting rods, and by the pylon (40).

4. Assembly according to claim 3, in which the connecting rods (30a, 30b) form between them an angle of between 2° and 50°, and preferably between 20° and 40°.

5. Assembly according to one of claims 1 to 4, in which the second end (32, 32a, 32b) of the or each connecting rod (30, 30a, 30b) is directly connected to the pylon (40).

6. An assembly according to one of claims 1 to 4, wherein the second end (32, 32a, 32b) of the or each connecting rod (30, 30a, 30b) is connected to an intermediate structure (50) which is fixed both to the pylon (40) and to the fan casing (11).

7. An assembly according to any one of the preceding claims, wherein the fan casing (11) comprises a fan casing (29) and an inlet casing (25) located downstream of the fan casing (29), the attachment point (11a, 11b) being located on a downstream axial end (29b) of the fan casing (29) or on an upstream axial end (25a) of the inlet casing (25).

8. Assembly according to one of the preceding claims, in which the pylon (40) comprises an upstream end (42) located in a plane (P2) perpendicular to the longitudinal axis (X) and located upstream of the combustion chamber (19), and preferably upstream of the second axial end (13) of the fan casing (11).

9. Assembly according to one of the preceding claims, in which the connecting elements comprise thrust recovery connecting rods (45) of which first ends (47) are connected to the gas generator (16), upstream of the combustion chamber (19) of the gas generator, and of which second opposite ends (48) are connected to the pylon (40).

10. An assembly according to one of the preceding claims, wherein the connecting elements comprise a suspension structure (49) fixed to the gas generator (16) and to the pylon (40), downstream of the combustion chamber (19) of the gas generator.

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