Propulsion System

Abstract

Propulsion assembly (100) comprising a turbomachine (8) extending along a longitudinal axis (X) including a casing (10) and suspension means (20) for attaching the turbomachine to an aircraft, the suspension means (20) comprising a first portion (21) rigidly fixed to a first connecting member (31) carried by an annular ferrule (11) of the casing (10) and wherein the suspension means (20) comprise a second portion (22) connected to a second connecting member (32) carried by the annular ferrule (11), said second portion (22) being connected to the second connecting member (32) with clearance in at least one radial direction. Fig. 2

Description

Title of the invention: Propulsion assembly

[0001] The present disclosure relates to a propulsion assembly comprising a turbomachine and means for suspending the turbomachine from an aircraft. Prior art

[0002] A bypass turbojet engine conventionally comprises an annular flow path for a primary air flow or primary annular flow path comprising, from upstream to downstream in the direction of circulation of the gas flow within the turbomachine, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine and a low-pressure turbine. The turbojet engine also comprises an annular flow path for a secondary air flow or flow path externally surrounding the primary annular flow path. The primary and secondary annular flow paths are coaxial, the secondary annular flow path being arranged radially outside the primary air flow path. The terms radial and axial are defined relative to the axis of the turbomachine. The terms upstream and downstream are defined relative to the direction of circulation of the gas flows within the turbomachine.

[0003] The turbojet engine is generally attached to a pylon or mast of an aircraft, said pylon itself being attached to the structure of the aircraft, for example to the wing. The pylon allows the forces generated by the turbojet engine to be transmitted to the structure of the aircraft and also allows the routing of fuel, air and electrical and hydraulic systems between the turbojet engine and the aircraft.

[0004] Patent application FR 2 867 155 in the name of the Applicant discloses a turbomachine attached to a pylon by means of a suspension assembly comprising an upstream suspension assembly and a downstream suspension assembly. The upstream suspension assembly is attached to an intermediate casing secured to a fan casing, the downstream suspension assembly being attached to an exhaust casing. The two casings are structural elements of the turbomachine.

[0005] The function of the suspension devices is to ensure the transmission of mechanical forces between the turbomachine and the pylon. These forces are in particular the thrust generated by the turbomachine, oriented along the axis of the turbomachine, the lateral aerodynamic loads and the weight of the turbomachine.

[0006] In the remainder of the description, we will focus as an example on the suspension assembly located upstream.

[0007] Such a known upstream suspension assembly conventionally comprises a beam intended to be fixed to a pylon of an aircraft, a cylindrical part articulated on a ball joint housing, the ball joint housing comprising a body, a ball joint nut articulated on the body, the cylindrical part being pivotally mounted around its axis in the nut ball joint. The body of the ball joint housing is attached to a fixed part of the turbojet, for example an intermediate casing or an inter-compressor casing, located between the low pressure compressor and the high pressure compressor of the primary vein.

[0008] In certain engine configurations, for example without fairing, the suspension assembly requires a fixing radially outside the casing, which requires a fixing projecting from the casing, this fixing also having to meet dimensional optimization constraints.

[0009] Due to the significant forces transmitted to the suspension assembly, the scenario of failure of the attachment must be considered, while ruling out the possibility of separation of the turbojet from the rest of the aircraft.

[0010] There is therefore a need to secure the attachment of the suspension assembly to the turbomachine.

[0011] There is also a need to improve the suspension devices, for a streamlined or unscaled turbomachine. Summary

[0012] There is thus proposed a propulsion assembly comprising a turbomachine extending along a longitudinal axis comprising a casing and means for suspending the turbomachine from an aircraft, the suspension means comprising a first part rigidly fixed to a first connecting member carried by an annular shell of the casing and in which the suspension means comprise a second part connected to a second connecting member carried by the annular shell, said second part being connected to the second connecting member with a clearance in at least one radial direction.

[0013] Furthermore, the first connecting member may comprise a first yoke for fixing the first part of the suspension means, said first yoke extending transversely along a transverse axis from the annular ferrule.

[0014] The second connecting member may furthermore be formed in one piece with the casing or be attached to the casing.

[0015] The second part may further comprise a rod connected to the second connecting member with clearance in at least the radial direction and in which the rod is secured to the first part and passes through the first connecting member. The rod may further be transversely traversed by a locking member, said locking member being connected to the second connecting member with clearance in at least the longitudinal direction.

[0016] In addition, the second connecting member may comprise two radial plates facing each other circumferentially, and extending radially from the annular ferrule and the locking member may comprise ends engaged in the radial plates with a first annular clearance. The radial plates may be secured to the first connecting member by a rupture zone, said rupture zone being configured to be broken so as to bring the locking member into contact with the two plates. radials.

[0017] Alternatively, the second connecting member may comprise a second yoke extending transversely along a transverse axis from the annular ferrule, and the rod may be engaged with a second annular clearance in the second yoke.

[0018] Furthermore, the locking member can be arranged with longitudinal play relative to the second yoke.

[0019] There is further provided an aircraft comprising a propulsion unit as described above. Brief description of the drawings

[0020] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which: Fig.l

[0021] [Fig.l] [Fig.l] is an overall view of a propulsion unit comprising a turbomachine extending along a longitudinal axis. Fig. 2

[0022] [Fig.2] [Fig.2] is an upstream perspective detail view of part of a propulsion unit according to a first example of embodiment. Fig. 3

[0023] [Fig.3] [Fig.3] is a detailed view in downstream perspective of the part of the assembly propulsive of [Fig.2]. Fig. 4

[0024] [Fig.4] [Fig.4] is a radial view of the part of the propulsion assembly of figures 2 and 3. Fig. 5

[0025] [Fig.5] [Fig.5] is an upstream perspective view of a propulsion unit according to a second example of realization. Fig. 6

[0026] [Fig.6] [Fig.6] is a radial view of the propulsion assembly of [Fig.5]. Description of the embodiments

[0027] [Fig.l] illustrates an overall view of a propulsion assembly 100 which notably comprises a turbomachine 8 extending along a longitudinal axis X, which turbomachine comprises a casing 10 and an annular shroud 11 of the casing. The propulsion assembly further comprises suspension means 20 for fixing the turbomachine to an aircraft. In the remainder of the description, and as illustrated by way of non-limiting example in [Fig.l], the suspension means 20 are arranged upstream of the turbomachine, i.e. towards the fan. The suspension means 20 comprise a beam 7, fixed to an aircraft pylon 9, and a cylindrical part 14, fixed to a annular shell 11 of a casing 10 of the turbomachine 8.

[0028] In the remainder of the description, the terms radial and longitudinal, upstream and downstream are defined relative to the axis of the turbomachine, denoted X in the figures. The longitudinal direction thus corresponds to the direction of the longitudinal axis X of the turbomachine. The longitudinal axis X coincides with an axis of rotation of the rotor parts of the turbomachine. A radial direction is a direction perpendicular to the longitudinal axis X.

[0029] As visible as an exemplary embodiment in Figures 2-5, the suspension means 20 comprise a first part 21 and a second part 22. The first part 21 is fixed to a first connecting member 31 of the annular ferrule 11 and the second part is connected to a second connecting member 32 of the annular ferrule 11.

[0030] The first connecting member 31 provides a fixed connection of the first part 21 of the suspension means to the annular ferrule 11. The fixed connection is a play-free attachment, i.e. without degrees of freedom, making the first part 21 and the annular ferrule 11 integral, i.e. the first part 21 is firmly fixed to the annular ferrule 11, for example by screws passing through the first part 21 and inserted into the annular ferrule 11. The first part 21 may for example be an annular crown arranged on the cylindrical part 14 of the suspension means. The second connecting member 32 provides a connection with play, at least in the radial direction (along the Z axis). The second member can also provide play in the longitudinal direction (X axis) between the second part 22 of the suspension means and the annular ferrule 11. There is therefore no contact between the second member 32 and the second part 22.

[0031] In this configuration, under normal operating conditions of the turbomachine, all the forces generated by the turbomachine pass through the first connecting member 31 of the annular shell 11 to which the first part 21 of the suspension means 20 is rigidly fixed. Due to the high mechanical stresses applied, for safety reasons, the scenario of mechanical failure, resulting in the appearance of deformations, or even cracks, or cracks, on the first connecting member 31 must be considered, which could result in the partial or total detachment of the first connecting member 31 from the rest of the casing and thus by the detachment of the suspension assembly 20 from the turbomachine. The forces transmitted by the first connecting member 31 would then be either reduced (in the case of deformations of said member), or non-existent (if the first connecting member is detached from the rest of the casing).

[0032] To overcome this drawback, the second part 22 of the suspension means is connected to the second connecting member 32 of the annular ferrule 11 with a clearance according to less the radial direction, and for example in the radial and longitudinal directions. This clearance makes it possible to create a standby force path, which will be functional only in the event of mechanical failure of the first connecting member 31. More precisely, the second connecting member 32 is stressed only in the event of failure: the clearance present between the second connecting member 32 and the second part 22 prevents contact of said second part 22 with the shell 11 in normal operating conditions, and all the forces pass through the first connecting member 31. The failure of the mechanical connection between the first part 21 and the first connecting member 31 creates a displacement of the first connecting member, which brings the second part 22 into contact with the second connecting member 32 of the shell, this allowing the continuity of the transmission of forces from the turbomachine to the suspension means.The assembly formed by the second connecting member 32 and the second part 22 of the suspension means thus represents a fixing awaiting failure, which becomes operational when the first connecting member 31 of the ferrule on which the first part 21 is fixed no longer correctly fulfills its role of fixing the suspension assembly to the casing element. The assembly formed by the second connecting member 32 and the second part 22 of the suspension means thus presents a waiting force path, which becomes operational when the first connecting member loses its mechanical integrity.

[0033] The connection with clearance also has the advantage of allowing a failure check of the turbomachine, by dimensional comparison of the clearance at a given instant with the known clearance under normal operating conditions.

[0034] As can be seen by way of example in Figures 2-5, the first connecting member may be a first yoke 31. The first yoke 31 extends transversely along a transverse axis Y, and is carried by the annular ferrule 11. In other words, the first yoke 31 projects in a radial direction from the external surface of the annular ferrule 11. The first yoke 31 has a downstream face 31a, on which the first part 21 arranged in a crown on the cylindrical part 14 is fixed and an upstream face 31b. The first yoke 31 further comprises an opening 31c, allowing the cylindrical part 14 to pass through, and in particular a rod 23 detailed below.

[0035] The second part 22 of the fixing means 20 is carried by the cylindrical part 14. The first and second parts 21, 22 are therefore integral with each other. The second part 22 comprises a rod 23, extending longitudinally. The rod 23 is transversely traversed by a locking member 24. The locking member 24 can be fixed to the rod 23, for example by a screw 19 integral with the locking member 24 and the rod 23. The locking member 24 is connected to the second connecting member 32.

[0036] According to the exemplary embodiments, the connection of the first part 21 with the locking member 24 may comprise a first annular clearance J1 (figures 2 to 4) or a second annular clearance J2 (figures 5 and 6), depending on the embodiment of the second connecting member.

[0037] According to the first embodiment (Figures 2 to 4), the second connecting member 32 comprises two plates 26 extending longitudinally and projecting radially from the annular shell 11. The plates 26 are formed in one piece with the casing 10. In another example not illustrated, the plates can be attached to the casing, for example by fixing the plates 26 to the casing. The plates 26 have the general shape of a reinforcement arranged on the upstream face 31b of the first connecting member 31. The plates 26 can further be secured to the first connecting member by a rupture zone 40, configured to be broken in the event of failure of the first connecting member 31, which separates the plates 26 from the first yoke 31.The rupture zone 40 is arranged radially in the upper part relative to a slot or groove 41, separating the plate 26 from the first yoke 31, at the external surface of the annular ferrule 11. The groove 41 conditions the dimension of the rupture zone 40: the more the groove extends radially, the smaller the radial dimension of the rupture zone 40, which favors the appearance of a crack for the rupture in this zone 40. The groove 41 also makes it possible to separate the second connecting member 32 from the first connecting member 31 at the ferrule 11, which prevents the propagation of an incipient crack or crack on the base of the first connecting member 31 in contact with the ferrule 11.

[0038] Each plate 26 further comprises a first opening 27 in which one end 25 of the locking member 24 is engaged. The first opening 27 and the section of the locking member 24 are of complementary circular shape. Nevertheless, the locking member 24 comprises a diameter slightly smaller than that of the first opening 27. The locking member 24 is thus engaged in the first opening 27 of the plate 26 with a first annular clearance J1, equivalent for example to one tenth of the diameter of the locking member 24.

[0039] In the event of mechanical failure of the attachment of the suspension means 20 to the first connecting member 31, the standby force path is activated by bringing the end 25 into contact with the first opening 27, which allows a transfer of longitudinal and radial forces between the shell and the suspension means.

[0040] According to the second embodiment (figures 5 and 6), the second connecting member is a second yoke 32. The second yoke 32 may comprise a first portion 32a extending transversely and radially and arranged opposite and without contact with the upstream face 31b of the first yoke 31, and a second portion 32b extending longitudinally and transversely. The second yoke may further be attached to the casing 10 and thus fixed to the annular shell 11 by radial fixing elements 33 fixing the second portion 32b to the annular shell 11. Alternatively, the second yoke 32 may be formed in one piece with the casing, and may comprise only a first portion 32a projecting radially from the annular ferrule 11.

[0041] The first portion 32a of the second yoke 32 comprises a second opening 50 in which the rod 23 is engaged. The second opening 50 and the rod section 23 are of complementary circular shape. However, the rod 23 comprises a diameter slightly smaller than that of the second opening 50. The rod 23 is thus engaged in the second opening 50 of the second yoke 32 with a second annular clearance J2.

[0042] Furthermore, in the longitudinal direction, the locking member is arranged with a longitudinal clearance J3 with respect to the second yoke, this clearance J3 being non-zero. In other words, the locking member is arranged at a distance D24 along the axis X from the second yoke.

[0043] In the event of mechanical failure of the attachment of the suspension means 20 to the first connecting member 31, the standby force path is activated on the one hand by the rod 23 coming into contact with the second opening 50, which allows a transfer of the radial and transverse forces between the ferrule and the suspension means and on the other hand by the locking member 24 coming into contact with the first portion 32a of the second yoke 32, which allows a transfer of the longitudinal forces between the ferrule and the suspension means.

[0044] In a manner common to the different embodiments, the second connecting member 32 is dimensioned so as to withstand a residual load level, called limit load, lower than the maximum load that the first connecting member 31 can withstand. This dimensioning remains sufficient to temporarily transmit the forces in the event of failure of the first connecting member 31, before inspection and control of the clearance(s) arranged between the second part 22 and the second connecting member, indicating the absence or presence of a mechanical failure.

Claims

Claims

1. Propulsion assembly (100) comprising a turbomachine (8) extending along a longitudinal axis (X) comprising a casing (10) and means (20) for suspending the turbomachine from an aircraft, the suspension means (20) comprising a first part (21) rigidly fixed to a first connecting member (31) carried by an annular ferrule (11) of the casing (10) and in which the suspension means (20) comprise a second part (22) connected to a second connecting member (32) carried by the annular ferrule (11), said second part (22) being connected to the second connecting member (32) with a clearance (J1, J2) in at least one radial direction, said assembly in which the second part (22) comprises a rod (23) connected to the second connecting member (32) with a clearance (J2) in at least the radial direction and in which the rod (23) is integral of the first part (21) and passes through the first connecting member (31),the rod (23) being transversely crossed by a locking member (24), said locking member (24) being connected to the second connecting member (32) with a clearance (J3) in at least the longitudinal direction.,

2. Assembly according to claim 1, in which the first connecting member (31) is a first yoke for fixing the first part (21) of the suspension means (20), said first yoke extending transversely along a transverse axis (Y) from the annular ferrule (11).

3. Assembly according to claim 1 or 2 in which the second connecting member (32) is formed in one piece with the casing (10) or is attached to the casing (10).

4. Assembly according to one of the preceding claims, in which the second connecting member (32) comprises two radial plates (26) facing each other circumferentially, and extending radially from the annular ferrule (11) and in which the locking member (24) comprises ends (25) engaged in the radial plates (26) with a first annular clearance (Jl).

5. Assembly according to claim 4, in which the radial plates (26) are integral with the first connecting member (31) by a rupture zone (40), said rupture zone being configured to be broken so as to bring the locking member (24) into contact with the two radial plates (26).

6. Assembly according to claim one of the preceding claims, in which the second connecting member (32) is a second yoke extending transversely along a transverse axis (Y) from the annular ferrule (11), and in which the rod (23) is engaged with a second annular clearance (J2) in the second yoke (32).

7. Assembly according to claim 6, in which the locking member (24) is arranged with a longitudinal clearance (J3) with respect to the second yoke (32).

8. Aircraft comprising a propulsion unit according to any one of the preceding claims.

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