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, the assembly further comprising at least one system (40) for limiting relative movements between the turbomachine (10) and the pylon (32), which comprises a first fixed member (42) connected to the pylon (32) and comprising at least one first stop element (44), and a second fixed member (46) connected to the turbomachine (10) and comprising at least one second stop element (48), the first and second stop elements (44, 48) being parallel to the axis (A) and being separated from one another or from one another by at least one elastically deformable means (54) so as to cooperate together by stop and to limit the relative movements between the turbomachine (10) and the pylon (32). 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 / fan blades 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 guration, 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 propeller fan blades, and to forces originating from the air capture (stick forces) by the turbomachine. In the case of an unducted propeller, the turbomachine undergoes a tilting force called IP mode.

[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 FR AI-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 first 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 second plane which is perpendicular to the axis and which is located downstream of the combustion chamber,

[0017] characterized in that said limitation system comprises a first fixed member connected to the pylon and comprising at least one first stop element, and a second fixed member connected to the turbomachine and comprising at least one second stop element, the first and second stop elements being parallel to the axis and being able to cooperate together by stop so as to limit the relative movements between the turbomachine and the pylon, and the first and second stop elements being separated from one another or from each other, by at least one elastically deformable means able to dampen said relative movements.

[0018] The invention thus proposes a system for limiting relative movements between the turbomachine and the pylon, which is simplified and which is equipped with an elastic member forming a shock absorber. The orientation of the elements, parallel to the longitudinal axis of the turbomachine, is advantageous because it allows relative movements between the turbomachine and the pylon in directions parallel to this axis. When the rear of the turbomachine moves in another or several other directions, the elements are intended to cooperate together by abutment to block the relative movements between the turbomachine and the pylon.

[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 in certain directions.

[0020] In the context of the present invention, the or each elastically deformable “means” may be a pad, a block, a pad, a layer, a coating, a link, etc.

[0021] The assembly according to the invention may comprise one or more of the characteristics following, taken individually or in combination with each other:

[0022] — the first plane is located upstream of the combustion chamber; - one of the first and second stop elements comprises a hollow tube, and the other of the first and second stop elements comprises a finger engaged in the hollow tube, the finger being separated from the hollow tube by said at least one means which extends all around the finger; - the finger is able to move axially in the hollow tube, for example over a distance greater than or equal to 50 mm; - said at least one means is formed by an annular layer of elastically deformable material which covers the interior of the hollow tube and which is fixed to the hollow tube; - said at least one means is formed by an annular layer of elastically deformable material which covers the finger and which is fixed to the finger; - the first stop element comprises a first plate, and the second stop element comprises a second plate, the first and second plates being separated by said at least one means; - one of the first and second stop elements comprises a third plate, the plate of one of the stop elements being interposed between the two plates of the other of the stop elements and being separated from these plates by said at least one means;

[0023] — the plates are tangent to circumferences centered on the axis;

[0024] — the two plates of one of the stop elements are connected together by a wall bottom which is separated by said at least one means of the plate from the other of the stop elements; - the first stop element comprises a finger engaged in a housing of the second stop element; - the finger or the interior of the housing is coated with a layer of deformable elastic material forming said at least one means; - the finger is connected to the inside of the housing by said at least one means;

[0025] — the first member is rigidly connected to the pylon;

[0026] — the first member is connected to the pylon by means of V or X connecting rods;

[0027] — the second element is rigidly connected to the turbomachine;

[0028] — the second element is connected to the turbomachine by means of V-shaped connecting rods or X ;

[0029] — the limitation system is located in a plane which passes through the pylon and through the axis of the turbomachine;

[0030] — the limitation system is located at 12 o'clock when the pylon is located at 12 o'clock (by analogy with the face of a clock);

[0031] — the limitation system is located between the pylon and the turbomachine, for example at 3 a.m. or 9 a.m.;

[0032] — the assembly comprises two limitation systems which are located respectively at 2-3 hours and 9-10 hours. Brief description of the figures

[0033] 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:

[0034] [Fig-1] [Fig.l] is a very schematic view of an assembly comprising a tur aircraft engine and its attachment pylon, according to the technique prior to the invention;

[0035] [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;

[0036] [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;

[0037] [Fig.4] [Fig.4] is a schematic perspective view of an assembly comprising an aircraft turbomachine and its suspension pylon;

[0038] [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;

[0039] [Fig.6] [Fig.6] is a schematic front view of the assembly of [Fig.5];

[0040] [Fig.7] [Fig.7] is a very schematic side view of an assembly comprising a aircraft turbomachine and its attachment pylon, according to an alternative embodiment of the invention;

[0041] [Fig.8] [Fig.8] 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;

[0042] [Fig.9] [Fig.9] is a very schematic view of a system for limiting the relative movements between the turbomachine and the pylon, according to another variant embodiment of the invention; and

[0043] [Fig. 10] [Fig. 10] is a very schematic view of a system for limiting relative movements between the turbomachine and the pylon, according to yet another variant embodiment of the invention. Detailed description of the invention

[0044] [Fig.l] shows a turbomachine 10 for an aircraft, this turbomachine 10 here being a double-flow, double-spool turbojet.

[0045] 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 axis A and oriented towards the front or the rear of the turbomachine 10, the Z axis is oriented upwards, and the Y axis is oriented towards one side.

[0046] 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.

[0047] 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 drives in rotation fan blades of a propulsion propeller located upstream of the gas generator 12 and which is surrounded by an annular casing called fan casing 24.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] The turbomachine 10 is fixed to an element of the aircraft by means of a pylon 32 which has a generally elongated shape along the axis A and which comprises members 34, 36, 38 for fixing and suspending the turbomachine 10.

[0053] Figures 1 to 4 illustrate the state of the art prior to the present invention.

[0054] 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.

[0055] The first plane PI is located upstream of the turbines 20, 22 and preferably upstream of the combustion chamber 18. The second plane P2 is located downstream of the combustion chamber 18.

[0056] 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.

[0057] 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.

[0058] [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.

[0059] 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.

[0060] 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.

[0061] The invention proposes an improvement to this principle, embodiments of which are illustrated in Figures 5 and following.

[0062] Generally, in the context of the present invention, the limitation system 40 comprises a first fixed member 42 connected to the pylon 32 and comprising at least one first stop element 44, and a second fixed member 46 connected to the turbomachine 10 and comprising at least one second stop element 48.

[0063] The first and second stop elements 44, 48 are capable of cooperating together by stop so as to limit the relative movements between the turbomachine 10 and the pylon 32.

[0064] The first and second stop elements 44, 48 are parallel to the axis A.

[0065] The first and second stop elements 44, 48 are separated from one another or from one another. of others, by at least one elastically deformable means 54 capable of damping the aforementioned relative movements.

[0066] Figures 5 and 6 illustrate a first embodiment of the invention in which one of the stop elements 44, 48 comprises a hollow tube 50, and the other of the stop elements 44, 48 comprises a finger 52 engaged in the hollow tube 50, the finger 52 being separated from the hollow tube 50 by the aforementioned means 54 which extends all around the finger 52 and is here in the form of an annular layer.

[0067] In the example shown, the finger 52 is connected to the turbomachine 10 and the hollow tube 50 is connected to the pylon 32. The reverse is however possible.

[0068] The connection of the finger 52 to the turbomachine 10 may be rigid. Alternatively, this connection is achieved by a suspension system, for example of bars or connecting rods crossed in an X or V configuration.

[0069] The connection of the hollow tube 50 to the turbomachine 10 may be rigid. Alternatively, this connection is achieved by a suspension system, for example of bars or connecting rods crossed in an X or V configuration.

[0070] The finger 52 is preferably able to move axially in the hollow tube 50 due to their respective orientations.

[0071] The interior of the hollow tube 50 may be coated with the annular layer forming the elastically deformable material means 54. The layer is then fixed to the hollow tube 50.

[0072] Alternatively, it is the finger 52 which can be coated with the annular layer forming the elastically deformable material means 54. The layer 54 is then fixed to the finger 52.

[0073] In operation, the finger 52 is able to slide axially inside the hollow tube 50 to allow relative movements of the turbomachine 10 with respect to the pylon 32 along the axis A. When the turbomachine 10 moves with respect to the pylon 32 in directions transverse to the axis A, these movements are damped and limited by abutment of the finger 52 and the hollow tube 50.

[0074] [Fig.7] illustrates an alternative embodiment of the invention in which the first stop element 44 comprises a first plate 56, and the second stop element 48 comprises a second plate 58, the first and second plates 56, 58 being separated by the aforementioned means 54.

[0075] In the example shown, each of the members 42, 46 comprises a single plate 56, 58. These plates 56, 58 are parallel to the axis A and more particularly tangent to circumferences centered on the axis A. The plates 56, 58 are separated by a single means 54 which may be in the form of a flat layer.

[0076] In operation, the plates 56, 58 can move axially freely relative to each other to allow relative movements of the turbomachine 10. with respect to the pylon 32 along the axis A. When the turbomachine 10 moves radially towards the pylon 32, this movement is damped and limited by the plates 56, 58 stopping against each other.

[0077] [Fig. 8] illustrates another alternative embodiment of the invention in which the first stop element 44 comprises two plates 56, 60, and the second stop element 48 comprises a plate 58 which is interposed between the two plates 56, 60 and which is separated from these plates by damping means 54.

[0078] These plates 56, 58 are parallel to the axis A and more particularly tangent to circumferences centered on the axis A. The plates 56, 58 are separated by two means 54 or layers for example.

[0079] Alternatively, it is the turbomachine 10 which could be connected to two plates between which a plate connected to the pylon 32 would be interposed.

[0080] The two trays 56, 60 can be connected together by a bottom wall 62 which is separated by the means 54 or a means independent of the tray 58.

[0081] It is in fact possible to connect the trays to each other and to the bottom wall 62 by several damping means 54 independent of each other or on the contrary a single damping means 54 capable of occupying all or part of the space between the trays and the bottom wall 62.

[0082] In operation, the movements of the plate 58 are damped and blocked by cooperation of the plates 56, 60 and the bottom wall 62.

[0083] Figures 8 and 9 illustrate other alternative embodiments of the invention in which the first stop element 44 comprises a finger 64 engaged in a housing 66 of the second stop element 48.

[0084] As shown in [Fig. 10], the finger 64 or the interior of the housing 66 may be coated with a layer of deformable elastic material forming the aforementioned damping means 54.

[0085] The operation of these variants is similar to the operation of the variant of [Fig.8].

[0086] As in the examples shown in the drawings, the limitation system can be located at 12 o'clock (12 hours) by analogy with the dial of a clock centered on the axis A. Alternatively, the assembly according to the invention could comprise two limitation systems arranged respectively around 2-3 o'clock and 9-10 o'clock.

[0087] Generally speaking, the elastically deformable material usable in the context of the present invention may be an elastomer.

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 a 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 a first fixed member (42) connected to the pylon (32) and comprising at least a first stop element (44), and a second fixed member (46) connected to the turbomachine (10) and comprising at least a second stop element (48), the first and second stop elements (44, 48) being parallel to the axis (A) and being able to cooperate together by stop so as to limit the relative movements between the turbomachine (10) and the pylon (32), and the first and second stop elements (44, 48) being separated from one another or from each other, by at least one elastically deformable means (54) able to dampen said relative movements.,

2. An assembly according to claim 1, wherein one of the first and second stop members (44, 48) comprises a hollow tube (50), and the other of the first and second stop members (48, 44) comprises a finger (52) engaged in the hollow tube (50), the finger (52) being separated from the hollow tube (50) by said at least one means (54) which extends all around the finger (52).

3. An assembly according to claim 2, wherein the finger (52) is capable of moving axially in the hollow tube (50).

4. An assembly according to claim 2 or 3, wherein said at least one means (54) is formed by an annular layer (54) of elastically deformable material which covers the interior of the hollow tube (50) and which is fixed to the hollow tube (50).

5. An assembly according to claim 2 or 3, wherein said at least one means (54) is formed by an annular layer (54) of elastically deformable material which covers the finger (52) and which is fixed to the finger (52).

6. An assembly according to claim 1, wherein the first stop element (44) comprises a first plate (56), and the second stop element (48) comprises a second plate (58), the first and second plates (56, 58) being separated by said at least one means (54).

7. An assembly according to claim 6, wherein one of the first and second stop elements (44, 48) comprises a third plate (60), the plate (58) of one of the stop elements (44, 48) being interposed between the two plates (56, 60) of the other of the stop elements (48, 44) and being separated from these plates (56, 60) by said at least one means (54).

8. An assembly according to claim 1 or 2, wherein the first stop element (44) comprises a finger (64) engaged in a housing (66) of the second stop element (48).

9. An assembly according to claim 8, wherein the finger (64) or the interior of the housing (66) is coated with a layer (54) of deformable elastic material forming said at least one means (54).

10. An assembly according to claim 8, wherein the finger (64) is connected to the interior of the housing (66) by said at least one means (54).

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