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 comprising a system (40) for limiting relative movements between the turbomachine (10) and the pylon (32), this system (40) comprising a first fixed member (42) connected to the pylon (32) and comprising at least one first stop element (44), and a second fixed member (44) connected to the turbomachine (10) and comprising at least one second stop element (48), the first and second stop elements (44, 48) being capable of cooperating together by stop and being separated from each other by at least one clearance (J). Figure for the 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 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 separated from one another or from each other, by at least one predetermined clearance in at least one given direction, so that the first and second stop elements cooperate together by abutment after consumption of said at least one clearance so as to limit the relative movements between the turbomachine and the pylon.

[0018] The invention thus proposes a system for limiting relative movements between the turbomachine and the pylon, which is of the "clearance(s)" type. This means that at rest and by default, the members and the stop elements do not cooperate with each other. There is no particular support between these members and elements insofar as there are no relative movements between the turbomachine and the pylon. When the rear of the turbomachine moves, the clearance(s) between the members and elements are consumed and the members and elements are intended to cooperate together by abutment to block the relative movements between the turbomachine and the pylon beyond the consumption of the clearances. In other words, the clearance is present in an initial / rest position, and is consumed in an active position.

[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] According to the invention, there may be play between the elements in one direction or multiple clearances in one or more directions. For example, there may be clearance in the radial direction relative to the axis of the turbomachine or even multiple clearances in this radial direction. There may also be a multitude of clearances when the elements are engaged with each other.

[0021] 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:

[0022]

[0023]

[0024] — the first plane is located upstream of the combustion chamber; - the first stop element extends along the axis and is preferably parallel to the axis, and / or the second stop element extends along the axis and is preferably parallel to the axis; - 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, said at least one clearance being present between the finger and the hollow tube, all around the finger; - the finger is able to move axially without contact in the hollow tube, for example over a distance greater than or equal to 50 mm; — the interior of the hollow tube is coated with an annular layer of elastically deformable material, which surrounds said finger with said at least one clearance; - 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 clearance; - 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 respectively by first and second sets; — the plates are parallel to the axis, and preferably tangent to circumferences centered on the axis, and therefore the first and second sets are radial sets with respect to the axis; - the two plates of one of the stop elements are connected together by a bottom wall which is separated by another or a third axial clearance with respect to the plate of the other of the stop elements; - the first stop element comprises a finger engaged with said at least one clearance in a housing of the second stop element;

[0025] — the finger or the interior of the housing is coated with a layer of elastic material deformable; - the or each game is empty; - the or each game is filled with a non-structural material, for example al- veolar;

[0026] — the first member is rigidly connected to the pylon;

[0027] — the first member is connected to the pylon by means of V or X connecting rods;

[0028] — the second element is rigidly connected to the turbomachine;

[0029] — the second element is connected to the turbomachine by means of V-shaped connecting rods or X ;

[0030] — the limitation system is located in a plane which passes through the pylon and through the axis of the turbomachine;

[0031] — 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);

[0032] — the limitation system is located between the pylon and the turbomachine, for example at 3h or 9h;

[0033] — the assembly comprises two limitation systems which are located respectively at 2-3h and 9-10h;

[0034] — the or each clearance is between 5 and 30mm, and preferably between 10 and 20mm. Brief description of the figures

[0035] 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:

[0036] [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;

[0037] [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;

[0038] [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;

[0039] [Fig.4] [Fig.4] is a schematic perspective view of an assembly comprising an aircraft turbomachine and its suspension pylon;

[0040] [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;

[0041] [Fig.6] [Fig.6] is a schematic front view of the assembly of [Fig.5];

[0042] [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;

[0043] [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;

[0044] [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

[0045] [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

[0046] [Fig.l] shows a turbomachine 10 for an aircraft, this turbomachine 10 here being a double-flow, double-spool turbojet.

[0047] 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.

[0048] 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 LP 14 or low pressure compressor, an HP 16 or high pressure compressor, an annular combustion chamber 18, an HP 20 or high pressure turbine and a LP 22 or low pressure turbine.

[0049] 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 propeller located upstream of the gas generator 12 and which is surrounded by an annular casing called fan casing 24.

[0050] 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.

[0051] 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.

[0052] 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 compressors BP 14 and HP 16, then mixed with fuel and burned in the combustion chamber 18. The combustion gases of the primary flow are then expanded in the turbines HP 20 and BP 22 and finally flow into an exhaust nozzle 30.

[0053] 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.

[0054] 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.

[0055] Figures 1 to 4 illustrate the state of the art prior to the present invention.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] [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.

[0061] 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.

[0062] 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.

[0063] The invention proposes an improvement to this principle, embodiments of which are illustrated in Figures 5 and following.

[0064] 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.

[0065] 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.

[0066] The first and second stop elements 44, 48 are separated from each other or from each other, by at least one predetermined clearance J in at least one given direction, so that the stop elements 44, 48 cooperate together by abutment after consumption of clearance J or these clearances J.

[0067] The or each clearance is for example between 5 and 30mm, and preferably between 10 and 20mm.

[0068] Figures 5 and 6 illustrate a first embodiment of the invention in which the first stop element 44 extends along the axis A and is preferably parallel to the axis A, and the second stop element 48 extends along the axis A and is preferably parallel to the axis A.

[0069] As illustrated in the drawings, 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, a clearance J being present between the finger 52 and the hollow tube 50, all around the finger 52.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] The finger 52 is preferably able to move axially without contact in the hollow tube 50 due to the aforementioned clearance(s).

[0074] The interior of the hollow tube 50 may be coated with an annular layer of elastically deformable material 54, which surrounds the finger 52 with play.

[0075] 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 relative to the pylon 32 in transverse directions relative to the axis A, these movements are authorized until the corresponding clearance J is consumed, in each direction of movement, between the finger 52 and the hollow tube 50, then are blocked beyond these clearances to the extent that the finger 52 comes into abutment against the hollow tube 50 or against its layer 54. The presence of this layer 54 of elastically deformable material makes it possible to dampen the movement of the finger 52 over part of its travel inside the tube 50.

[0076] [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 a clearance J.

[0077] 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 clearance which is oriented radially relative to the axis A.

[0078] In operation, the plates 56, 58 can move axially freely relative to each other to allow relative movements of the turbomachine 10 relative to the pylon 32 along the axis A. When the turbomachine 10 moves radially towards the pylon 32, this movement is allowed until the clearance between the plates 56, 58 is consumed, then is blocked beyond the clearance to the extent that the plates 56, 58 come into abutment against each other. The presence of a layer 54 of elastically deformable material on one or other of the plates 56, 58, or both, would make it possible to dampen this movement over part of the stroke.

[0079] [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 clearances J1, J2.

[0080] 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 sets J1, J2, oriented radially relative to the axis A.

[0081] 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 with play.

[0082] The two trays 56, 60 can be connected together by a bottom wall 62 which is separated by another clearance J3 from the tray 58.

[0083] In operation, the plate 58 can move freely, in the radial direction according to the clearances J1 and J2, and in the axial direction according to the clearance J3. Beyond these clearances, the relative movements of the turbomachine 10 are blocked. The presence of a layer of elastically deformable material on one or more of the plates 56, 58, 60 per- would cushion these movements.

[0084] Figures 8 and 9 illustrate other alternative embodiments of the invention in which the first stop element 44 comprises a finger 64 engaged with play(s) in a housing 66 of the second stop element 48.

[0085] As shown in [Fig. 10], the finger 64 or the interior of the housing 66 may be coated with a layer 54 of deformable elastic material.

[0086] The operation of these variants is similar to the operation of the variant of [Fig.8].

[0087] 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.

[0088] Generally speaking, the elastically deformable material usable in the context of the present invention may be an elastomer.

[0089] The aforementioned clearance(s) are advantageously empty, i.e. devoid of any material. However, as a variant, it would be possible to fill this clearance(s) with a non-structural material, for example cellular material such as foam.

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 (44) connected to the turbomachine (10) and comprising at least a second stop element (48), the first and second stop elements (44, 48) being separated from each other or from each other, by at least a predetermined clearance (J) in at least one given direction, so that the first and second stop elements (44, 48) cooperate together by abutment after consumption of said at least one clearance (J) so as to limit the relative movements between the turbomachine (10) and the pylon (32).,

2. An assembly according to claim 1, wherein the first stop element (44) extends along the axis (A) and is preferably parallel to the axis (A), and / or the second stop element (48) extends along the axis (A) and is preferably parallel to the axis (A).

3. An assembly according to claim 1 or 2, wherein one of the first and second stop elements (44, 48) comprises a hollow tube (50), and the other of the first and second stop elements (48, 44) comprises a finger (52) engaged in the hollow tube (50), said at least one clearance (J) being present between the finger (52) and the hollow tube (50), all around the finger (52).

4. An assembly according to claim 3, wherein the finger (52) is capable of moving axially without contact in the hollow tube (50).

5. An assembly according to claim 1 or 2, 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 clearance (J).

6. An assembly according to claim 5, 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) respectively by first and second sets (J1, J2).

7. An assembly according to claim 5 or 6, wherein the two plates (56, 60) of one of the stop elements (4, 48) are connected together by a bottom wall (62) which is separated by another axial clearance (J3) from the plate (58) of the other of the stop elements (48, 44).

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

9. An assembly according to one of the preceding claims, in which the or each set (J) is empty.

10. Assembly according to one of claims 1 to 8, in which the or each set (J) is filled with a non-structural material, for example cellular.

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