SET COMPRISING AN AIRCRAFT TURBOMACHINE AND ITS MOUNTING PYLON

Abstract

Assembly comprising an aircraft turbomachine (10) and a pylon (32) for attaching the turbomachine to an element of the aircraft, comprising at least one system (40) for limiting relative movements between the turbomachine (10) and the pylon (32), this system (40) being connected to the turbomachine (10) downstream of the combustion chamber (18), and comprising at least one cable (42) comprising a first end (42a) connected to the pylon (32) and a second end (42b) connected to the turbomachine (10), said at least one cable (42) being flexible from a rest position in the absence of relative movement between the turbomachine (10) and the pylon (32), to a taut active position in which the turbomachine (10) has moved relative to the pylon (32) and the tension of the cable (42) limits these movements. Figure for abstract: Figure 5

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] The state of the art includes in particular documents FR-A1-2 969 700, FR-A1-2 987 401 and FR-A1-3 118 992.

[0003] 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, an annular 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 defines an annular flow path for a gas stream which passes through the compressors, the combustion chamber and the turbines.

[0004] 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 propeller generally located upstream of the gas generator.

[0005] When this propeller is shrouded and therefore surrounded by an annular casing, this propeller is called a fan and generates an air flow which flows around the gas generator. When the propeller is not shrouded, it also generates an air flow which flows around the gas generator.

[0006] The turbomachine is attached to an element of the aircraft, such as a wing or the fuselage, by means of a mounting pylon also called a mast. This 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 located at 12 o'clock (12 o'clock) by analogy with the dial of a clock.

[0007] In the current technique, the pylon comprises upstream members for suspending the turbomachine and downstream members for suspending the turbomachine. This confi This configuration, however, has drawbacks. In fact, during operation, the gas generator transmits forces between the upstream and downstream attachment points to the pylon, which result in deformations of the gas generator and changes in the clearances between the rotors and stators of the gas generator. The gas generator is thus subjected to a moment generated by axial forces (off-axis thrust and thrust recovery). The turbomachine is also subjected to a moment generated by the asymmetry of axial forces on the fan propeller blades, and to forces originating from the air capture (stem forces) by the turbomachine.

[0008] It is therefore understood that the performance and operability of the turbomachine can be affected by these forces.

[0009] One solution to this problem is to fix the turbomachine to the pylon in a cantilevered manner. This therefore amounts to suspending a front or upstream part of the turbomachine from the pylon and leaving the rear or downstream part of the turbomachine free, such as its turbine casing for example.

[0010] However, the cantilever mounting of the turbomachine has disadvantages: - There is no longer any support for the rear part of the turbomachine, and therefore no more stop in the event of excessive movement of the turbomachine; - This cantilevered part will present a relatively low frequency rotating bending mode which can be excited by unbalances and in particular unbalances linked to the loss of a fan blade; - The loads associated with the loss of a low-pressure turbine blade will travel along the entire line of the cantilevered casing, which would result in significant loads and vibrations at the base of the cantilever but also significant displacements, particularly at the downstream end of the turbomachine; - Problems with the maintenance of casings and equipment linked to these casings; etc.

[0011] The Applicant has already proposed a solution to this problem in document FRAI-3 118 992. This solution consists of providing a damper between the turbomachine and the pylon, this damper being located downstream of the combustion chamber. This damper is configured to limit the relative movements between the turbomachine and the pylon without transmitting forces.

[0012] The present invention proposes an improvement to current technologies, which makes it possible to resolve at least some of the problems and drawbacks mentioned above. Summary of the invention

[0013] The invention relates to an assembly comprising an aircraft turbomachine and a pylon for attaching the turbomachine to an element of the aircraft,

[0014] the turbomachine having a longitudinal axis and comprising a gas generator comprising from upstream to downstream, in the direction of gas flow, at least one compressor, an annular combustion chamber and at least one turbine,

[0015] the pylon having a general elongated shape along said axis and comprising suspension members of the turbomachine, these members all being connected to the turbomachine in at least one plane which is perpendicular to the axis and which is located upstream of said at least one turbine so that the turbomachine is fixed in cantilever to the pylon,

[0016] the assembly further comprising at least one system for limiting relative movements between the turbomachine and the pylon, this system being connected to the turbomachine in at least one plane which is perpendicular to the axis and which is located downstream of the combustion chamber,

[0017] characterized in that said limitation system comprises at least one cable comprising a first end connected to the pylon and a second end connected to the turbomachine, said at least one cable being flexible from a rest position, preferably not tensioned, in the absence of relative movement between the turbomachine and the pylon, to a tensioned active position in which the turbomachine has moved relative to the pylon and the tension of the cable limits these movements.

[0018] The invention thus proposes a system for limiting relative movements between the turbomachine and the pylon, which is of the “cable(s)” type. This means that at rest and by default, the cable(s) is / are inactive and is / are not preferably tensioned. In this rest position, it / they are therefore not stressed because there are no relative movements between the turbomachine and the pylon. When the rear of the turbomachine moves, the cable(s) is / are likely to become tensioned according to the directions and the amplitude of the movements. When the cable or one of the cables becomes tensioned and becomes parallel to a direction, it limits or even blocks additional movements at least in this direction. It is therefore understood that the length of the cable(s), and their position(s), are chosen to allow relative movements between the turbomachine and the pylon in predetermined directions and amplitudes.

[0019] The elements and organs of the limitation system are not intended to transmit forces from the turbomachine to the pylon but only to block the relative movements of the turbomachine in operation.

[0020] The assembly according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another:

[0021] — the cable is non-extensible;

[0022] — the cable is extensible by elastic deformation;

[0023] — the first plane is located upstream of the combustion chamber; - said limitation system comprises at least two cables each comprising a first end connected to the pylon and a second end connected to the turbomachine, the cables being arranged symmetrically with respect to a vertical plane passing through the axis; - the second ends of the cables are connected to the turbomachine, respectively at 2 o'clock and 10 o'clock by analogy with the dial of a clock; - the second ends of the cables are connected to the turbomachine, respectively at 3 o'clock and 9 o'clock by analogy with the dial of a clock; - the second ends of the cables are connected to the turbomachine, respectively at Ih and at 1 Ih by analogy with the dial of a clock; - the second end of the or each cable is connected to an annular casing of the gas generator; - the casing is a turbine casing which surrounds said at least one turbine, or an exhaust casing which is located downstream of said at least one turbine; - the or each cable has a length greater than or equal to 50cm, and preferably greater than or equal to 1m and / or a diameter greater than 5mm; - the or each cable comprises an intermediate part, between its first and second ends, which passes around a pivot or a pulley carried by the turbomachine; - the pivot or pulley is located upstream of the second plane; - at least one connection point of the first end of the or each cable to the pylon is located upstream of the second plane or even upstream of the pivot or pulley; - the pivot or the pulley, and / or said at least one connection point of the first end of the or each cable to the pylon, is / are located at the level of said at least one first plane;

[0024] — in the vertical direction, at least one connection point of the second end of the or of each cable to the turbomachine, is located between the pivot or the pulley, and said at least one connection point of the first end of the or each cable to the pylon. Brief description of the figures

[0025] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0026] [Fig-1] [Fig.l] is a very schematic view of an assembly comprising a tur aircraft engine and its attachment pylon, according to the prior art the invention;

[0027] [Fig.2] [Fig.2] is a very schematic view of an aircraft turbomachine and shows points of attachment and suspension to a suspension pylon, according to the technique prior to the invention;

[0028] [Fig.3] [Fig.3] is a very schematic view of another aircraft turbomachine and shows points of attachment and suspension to a suspension pylon, according to the technique prior to the invention;

[0029] [Fig.4] [Fig.4] is a schematic perspective view of an assembly comprising an aircraft turbomachine and its attachment pylon;

[0030] [Fig.5] [Fig.5] is a very schematic side view of an assembly comprising an aircraft turbomachine and its attachment pylon, according to one embodiment of the invention;

[0031] [Fig.6] [Fig.6] is a schematic front view of an assembly comprising an aircraft turbomachine and its attachment pylon, according to an alternative embodiment of the invention;

[0032] [Fig.7] [Fig.7] is a view similar to that of [Fig.6] and which shows the whole of [Fig.6] after a first relative movement of the turbomachine with respect to the pylon;

[0033] [Fig.8] [Fig.8] is a view similar to that of [Fig.6] and which shows the whole of [Fig.6] after a second relative movement of the turbomachine with respect to the pylon;

[0034] [Fig.9] [Fig.9] is a view similar to that of [Fig.6] and which shows the whole of [Fig.6] after a third relative movement of the turbomachine with respect to the pylon;

[0035] [Fig. 10] [Fig. 10] is a very schematic side view of an assembly comprising an aircraft turbomachine and its attachment pylon, according to another variant embodiment of the invention; and

[0036] [Fig. 11] [Fig. 11] is a view similar to that of [Fig. 10] and which shows the whole of [Fig. 10] after a relative displacement of the turbomachine with respect to the pylon. Detailed description of the invention

[0037] [Fig.l] shows a turbomachine 10 for an aircraft, this turbomachine 10 here being a double-flow, double-spool turbojet.

[0038] The axis A designates the longitudinal axis of the turbomachine. The orthonormal reference XYZ is represented in certain figures including [Fig.l]. The X direction is parallel to the X axis and oriented upstream or forward of the turbomachine 10, the Z axis is oriented upwards, and the Y axis is oriented to one side.

[0039] The turbomachine 10 comprises a gas generator 12 which comprises, from upstream to downstream with reference to the flow of gases along the axis A, a low pressure or LP compressor 14, a high pressure or HP compressor 16, an annular combustion chamber 18, a high pressure or HP turbine 20 and a low pressure or LP turbine 22.

[0040] Although this is not visible in [Fig.l], the rotor of the HP compressor 16 is connected to the rotor of the HP turbine 20 by a high pressure shaft, and the rotor of the LP compressor 14 is connected to the rotor of the LP turbine 22 by a low pressure shaft which passes through the high pressure shaft and which rotates a propulsion propeller located upstream of the gas generator 12 and which is surrounded by an annular casing called the fan casing 24.

[0041] The fan casing 24 is connected to the gas generator 12 by an intermediate casing 26 which comprises a central hub 28 and a series of radial arms connecting the hub 28 to the fan casing 24.

[0042] The gas generator 12 defines a main annular flow vein for a first air flow, called the primary flow. The gas generator is surrounded by a secondary annular flow vein for a second air flow, called the secondary flow.

[0043] The air flow entering the blower is divided into a part forming the primary flow. The air of this primary flow is compressed in the LP 14 and HP 16 compressors, then mixed with fuel and burned in the combustion chamber 18. The combustion gases of the primary flow are then expanded in the HP 20 and LP 22 turbines and finally flow into an exhaust nozzle 30.

[0044] The other part of the air flow entering the blower forms the secondary flow and is intended to be mixed with the primary flow downstream of the nozzle 30.

[0045] The turbomachine 10 is fixed to an element of the aircraft by means of a pylon 32 which has a general elongated shape along the axis A and which comprises members 34, 36, 38 for fixing and suspending the turbomachine 10.

[0046] Figures 1 to 4 illustrate the state of the art prior to the present invention.

[0047] In the first case illustrated in Figures 1 and 2, there are three points or zones for attaching the pylon 32 to the turbomachine 10. Two of the points are located in an upstream or front plane PI perpendicular to the axis A and the last point is located in a downstream or rear plane P2 perpendicular to the axis A.

[0048] At the plane PI, a first fixing member 34 ensures the connection of the pylon 32 to the fan casing 24. At the plane P2, the fixing member 38 ensures the fixing of the pylon 32 to a turbine or exhaust casing 39. This fixing member 38 is further connected by thrust recovery bars 36 to the hub 28 of the intermediate casing 26. These bars 36 ensure the transmission of the thrust from the turbomachine 10 to the pylon 32 and therefore to the aircraft.

[0049] In the second case illustrated in [Fig. 3], there are only the two fixing points in the aforementioned plane PI, and therefore the turbomachine is fixed in cantilever to the pylon 32. In this case, at the level of the plane PI, the fixing member 34 ensures the connection of the pylon 32 to the fan casing 24, and thrust recovery connecting rods 36 ensure the connection of the hub 28 of the intermediate casing 26 to the pylon 32, by means of a fixing member (not shown) which is fixed to the pylon without being fixed to the turbomachine.

[0050] [Fig. 4] schematically illustrates the principle described in document FRAI-3 118 992 which is to provide, in addition to the suspension members 34, 36 of the turbomachine 10 which are located upstream of the combustion chamber 18, a system 40 for limiting the relative movements between the turbomachine 10 and the pylon 32 and which is located downstream of the combustion chamber 18.

[0051] The members 34, 36 take up the loads in the directions Y and Z as well as the moments Mx, My and Mz in all directions. The thrust of the turbomachine in the direction X is taken up by a system integrated into the members 34 or 36 or independent.

[0052] The system 40 is located at the level of a plane P2 which is perpendicular to the axis A and which passes for example through a turbine or exhaust casing of the turbomachine 10.

[0053] The invention proposes an improvement to this principle, embodiments of which are illustrated in Figures 5 and following.

[0054] Generally, within the framework of the present invention, the limitation system 40 comprises at least one cable 42.

[0055] The or each cable 42 comprises a first end 42a connected to the pylon 32 and a second end 42b connected to the turbomachine 10 and in particular to the gas generator 12.

[0056] By nature, the cable 42 is flexible. For example, it has a length greater than or equal to 50 cm, and preferably greater than or equal to 1 m. For example, it has a diameter greater than 5 mm.

[0057] The cable 42 can be made of steel for example.

[0058] The or each cable 42 is flexible from a rest position, preferably not tensioned, which is illustrated in [Fig.5], in the absence of relative movement between the turbomachine 10 and the pylon 32.

[0059] The cable 42 may be non-extensible. Alternatively, it may be extensible, preferably by elastic deformation.

[0060] The or each cable 42 is flexible up to a taut active position in which the turbomachine 10 has moved relative to the pylon 32 and the tension of the cable 42 limits these movements.

[0061] The second end 42a of the or each cable 42 is preferably connected to a annular casing of the gas generator 12. This casing may be a turbine casing 44 which surrounds said at least one turbine, or an exhaust casing 39 which is located downstream of said at least one turbine.

[0062] In the embodiment of [Fig.5], at least one point XI for connecting the first end 42a of the or each cable 42 to the pylon 32 is located downstream of the turbomachine 10 and therefore downstream of the point X2 for attaching the second end 42a of the or each cable 42 to the turbomachine 10 on a cold engine.

[0063] Figures 6 to 9 illustrate an alternative embodiment in which the limitation system comprises at least two cables 42

[0064] Each of the cables 42 has a first end 42a connected to the pylon 32 and a second end 42b connected to the turbomachine 10.

[0065] The cables 42 are arranged symmetrically with respect to a median vertical plane H1 of the turbomachine 10 which passes through the axis A.

[0066] The second ends 42b of the cables 42 may be connected to the turbomachine 10, respectively at 2h (2 o'clock) and at 10h (10 o'clock) by analogy with the dial of a clock. Alternatively, the second ends 42b of the cables 42 may be connected to the turbomachine 10, respectively at 3h and at 9h by analogy with the dial of a clock. Alternatively, the second ends could be connected to the turbomachine, respectively at 1h (1 o'clock) and at 11h (11 o'clock), or respectively 3h (3 o'clock) and 9h (9 o'clock).

[0067] In Figures 6 to 9, it can be seen that the point XI for fixing the first ends 42a of the cables 42 is common to both cables 42. It can also be seen that this point XI is located in the median vertical plane HL.

[0068] Note that point XI may be common to the cables 42 or may comprise two points or sub-points symmetrical with respect to the vertical median plane.

[0069] [Fig. 6] shows the assembly according to the invention at rest. There are no relative movements between the turbomachine 10 and the pylon 32 and the cables 42 are not taut.

[0070] [Fig.7] shows a relative displacement of the turbomachine 10 with respect to the pylon 32 towards the left of the drawing. The cables 42 deform or flex and one of them tightens to block the relative displacement beyond a certain amplitude.

[0071] [Fig.8] shows a relative displacement of the turbomachine 10 with respect to the pylon 32 towards the right of the drawing. The cables 42 deform or flex and one of them tightens to block the relative displacement beyond a certain amplitude.

[0072] [Fig.9] shows a relative displacement of the turbomachine 10 with respect to the pylon 32 vertically downwards, therefore on the side opposite the pylon 32. The cables 42 deform or flex and stretch to block the relative displacement beyond a certain amplitude.

[0073] Figures 10 and 11 illustrate another alternative embodiment in which the limitation system 40 comprises at least two cables 42

[0074] Each of the cables 42 has a first end 42a connected to the pylon 32 and a second end 42b connected to the turbomachine 10.

[0075] The cables 42 are arranged symmetrically with respect to the median vertical plane H1 of the turbomachine 10 which passes through the axis A.

[0076] In this variant, the or each cable 42 comprises an intermediate part 42c, between its first and second ends 42a, 42b, which passes around a pivot 46 or a pulley carried by the turbomachine 10.

[0077] The pivot 46 or the pulley is preferably located upstream of the second plane P2.

[0078] The point XI of connection of the first end 42a of the or each cable 42 to the pylon 32 is preferably located upstream of the second plane P2 or even upstream of the pivot 46 or the pulley.

[0079] The pivot 46 or the pulley, and / or the point XI of connection of the first end 42a of the or each cable 42 to the pylon 32, is / are located at the level of said at least one first plane PL

[0080] In the vertical direction, the point X2 of connection of the second end 42b of the or each cable 42 to the turbomachine 10, is located between the pivot 46 or the pulley, and the point XI of connection of the first end 42a of the or each cable 42 to the pylon 32.

[0081] [Fig. 10] shows the assembly according to the invention at rest. There are no relative movements between the turbomachine 10 and the pylon 32 and the cables 42 are not taut.

[0082] [Fig. 11] shows a relative displacement of the rear of the turbomachine 10 with respect to the pylon 32, upwards and towards the pylon. The cables 42 deform and become taut as they pass around the pivot 46 or the pulley, thus blocking the relative displacement beyond a certain amplitude.

Claims

Claims

1. Assembly comprising an aircraft turbomachine (10) and a pylon (32) for attaching the turbomachine to an element of the aircraft, the turbomachine (10) having a longitudinal axis (A) and comprising a gas generator (12) comprising from upstream to downstream, in the direction of gas flow, at least one compressor (14, 16), an annular combustion chamber (18) and at least one turbine (20, 22), the pylon (32) having a generally elongated shape along said axis (A) and comprising members (34, 36) for suspending the turbomachine (10), these members (34, 36) all being connected to the turbomachine in at least one first plane (PI) which is perpendicular to the axis (A) and which is located upstream of said at least one turbine (20, 22) so that the turbomachine (10) is fixed in cantilevered to the pylon (32), the assembly further comprising at least one system (40) for limiting relative movements between the turbomachine (10) and the pylon (32),this system (40) being connected to the turbomachine (10) in at least one second plane (P2) which is perpendicular to the axis (A) and which is located downstream of the combustion chamber (18), characterized in that said limitation system (40) comprises at least one cable (42) comprising a first end (42a) connected to the pylon (32) and a second end (42b) connected to the turbomachine (10), said at least one cable (42) being flexible from a rest position in the absence of relative movement between the turbomachine (10) and the pylon (32), to a taut active position in which the turbomachine (10) has moved relative to the pylon (32) and the tension of the cable (42) limits these movements.,

2. An assembly according to claim 1, wherein said limitation system (40) comprises at least two cables (42) each having a first end (42a) connected to the pylon (32) and a second end (42b) connected to the turbomachine (10), the cables (42) being arranged symmetrically with respect to a vertical plane (Hl) passing through the axis (A).

3. Assembly according to claim 2, in which the second ends (42b) of the cables (42) are connected to the turbomachine (10), respectively at 1h and 1h, or respectively at 2h and 10h, or respectively at 3h and 9h, by analogy with the dial of a clock.

4. An assembly according to one of the preceding claims, in which the second end (42b) of the or each cable (42) is connected to an annular casing of the gas generator (12).

5. An assembly according to claim 4, wherein the casing is a turbine casing (44) which surrounds said at least one turbine (20), or an exhaust casing (39) which is located downstream of said at least one turbine (20).

6. Assembly according to one of the preceding claims, in which the or each cable (42) has a length greater than or equal to 50cm, and preferably greater than or equal to 1m and / or a diameter greater than 5mm.

7. Assembly according to one of the preceding claims, in which the or each cable (42) comprises an intermediate part (42c), between its first and second ends (42a 42b), which passes around a pivot (46) or a pulley carried by the turbomachine (10).

8. An assembly according to claim 7, wherein the pivot (46) or the pulley is located upstream of the second plane (P2).

9. Assembly according to claim 7 or 8, in which at least one point (XI) of connection of the first end (42a) of the or each cable (42) to the pylon (32) is located upstream of the second plane (P2) or even upstream of the pivot (46) or the pulley.

10. Assembly according to one of claims 7 to 9, in which the pivot (46) or the pulley, and / or said at least one point (XI) of connection of the first end (42a) of the or each cable (42) to the pylon (32), is / are located at the level of said at least one first plane (PI).

Images