Attachment of an aeronautical propulsion system

Abstract

This presentation concerns an assembly comprising: a pylon (40) configured to be fixed to an aircraft fuselage; an aircraft propulsion system extending along a longitudinal axis (X); and a fastening system (51) isostatically connecting the aircraft propulsion system to the pylon (40). The fastening system (51) comprises a first fastening device (51) connecting the aircraft propulsion system to the pylon (40), allowing any translation of the aircraft propulsion system relative to the pylon (40) and any rotation of the aircraft propulsion system, relative to the pylon (40), about an axis perpendicular to the longitudinal axis (X), and prohibiting any rotation of the aircraft propulsion system, relative to the pylon (40), about the longitudinal axis (X). Figure 6 (for the abbreviation)

Description

Title of the invention: Attachment of an aeronautical propulsion system technical field

[0001] The present exposition relates to the aeronautical field. More specifically, the present exposition relates to the attachment of an aeronautical engine to an aircraft. STATE OF THE ART

[0002] In flight, an aircraft engine can be subjected to torsional stresses around its principal axis of extension, whether aerodynamic in origin or not. Such stresses can shear the longitudinal structural components of the engine, especially when the engine's suspension points on the aircraft are axially distant from each other. To compensate for such loads, it may be possible to reinforce these longitudinal structural components, but this increases the overall mass of the engine, and therefore its performance. It may also be possible to incorporate circumferential reinforcement elements attached to the longitudinal structural components, but this reduces engine accessibility, and therefore its maintenance. SUMMARY

[0003] One aim of the present exposition is to address the torsional stresses that an aeronautical engine undergoes around its main extension axis, without penalizing its mass or maintenance time.

[0004] In this regard, it is proposed, according to one aspect of the present exposition, a set comprising: a pylon configured to be attached to the fuselage of an aircraft; an aeronautical propulsion system extending along a longitudinal axis; and a fastening system connecting the aeronautical propulsion system to the pylon in an isostatic manner, the fastening system comprising a first fastening device connecting the aeronautical propulsion system to the pylon, permitting any translation of the aeronautical propulsion system relative to the pylon and any rotation of the aeronautical propulsion system, relative to the pylon, around an axis perpendicular to the longitudinal axis, and prohibiting any rotation of the aeronautical propulsion system, relative to the pylon, around the longitudinal axis.

[0005] The fastening system may further include: a second fastening device connecting the aeronautical propulsion system to the pylon, allowing any rotation of the aeronautical propulsion system relative to the pylon, and prohibiting any translation of the aeronautical propulsion system relative to the pylon; and a third fixing device linking the aeronautical propulsion system to the pylon, permitting translation of the aeronautical propulsion system relative to the pylon along the longitudinal axis and any rotation of the aeronautical propulsion system relative to the pylon, and prohibiting any translation of the aeronautical propulsion system relative to the pylon along an axis perpendicular to the longitudinal axis; and in which the first fixing device is positioned axially between the second fixing device and the third fixing device.

[0006] The aeronautical propulsion system may further include: a fan rotor configured to draw in an airflow; and a generator configured to drive the fan rotor, and comprising a first part and a second part extending from the first part to an end axially opposite to the fan rotor; in which the fixing system connects the first part of the generator to the pylon in an isostatic manner, leaving the end of the second part of the generator mobile relative to the pylon. The aeronautical propulsion system may include a fan shaft driving the fan rotor, and the generator includes a drive shaft configured to drive the fan shaft; wherein the first part of the generator of the aeronautical propulsion system includes a casing supporting the fan shaft and the drive shaft; and wherein the first fastening device connects the casing to the pylon, permits any translation of the casing relative to the pylon and any rotation of the casing about an axis perpendicular to the longitudinal axis, and prohibits any rotation of the casing about the longitudinal axis. The second fixing device can connect the housing to the pylon, allow any rotation of the housing relative to the pylon, prohibit any translation of the housing relative to the pylon, and be positioned axially between the blower rotor and the first fixing device. The first part of the aeronautical propulsion system generator may include a tubular support extending axially from the casing to the end of the second part of the generator which is movable relative to the pylon, the tubular support surrounding the second part, the end of the second part movable relative to the pylon being further movable relative to the tubular support, and the third fixing device connecting the tubular support to the pylon, permitting a translation of the tubular support relative to the pylon along the longitudinal axis and any rotation of the tubular support relative to the pylon, and prohibiting any translation of the tubular support relative to the pylon along an axis perpendicular to the longitudinal axis.

[0007] The first fastening device of the fastening system may include a coupling element, a pivot joint connecting the coupling element to the pylon, a first connecting rod, a first ball joint linking the first connecting rod to the coupling element, a second ball joint linking the first connecting rod to the aeronautical propulsion system, a second connecting rod, a third ball joint linking the second connecting rod to the coupling element, and a fourth ball joint linking the second connecting rod to the aeronautical propulsion system. The coupling element of the first fastening device of the fastening system may include a body connected to the pylon by the pivot joint, and an arm extending in a direction perpendicular to the longitudinal axis and in a direction radial to the longitudinal axis, connected to the first connecting rod by the first ball joint and to the second connecting rod by the third ball joint; in which the pivot joint of the first fastening device includes an axis fixed to the pylon and extending parallel to the arm of the coupling element by being axially offset with respect to the arm, the body of the coupling element being pivotally mounted on the axis. The aeronautical propulsion system and the pylon may have a common axial plane of symmetry which includes the longitudinal axis, the second ball joint and the fourth ball joint of the first fixing device of the fixing system being positioned on either side of the common axial plane of symmetry.

[0008] According to another aspect of the present exposition, an aircraft is proposed comprising a cell and an assembly according to the present exposition, in which the pylon of the assembly is fixed to the cell. DESCRIPTION OF THE FIGURES

[0009] Fig. 1 illustrates an example of an aircraft that may include a propulsion system.

[0010] Figure 2 is a schematic, partial, cross-sectional view of an example system dual-flow, twin-body propulsion system in which the fan section is enclosed.

[0011] Fig. 3 is a schematic, partial, cross-sectional view of an example of a dual-flow, dual-body propulsion system in which the blower section is unfaired.

[0012] Fig. 4 is a schematic, partial, cross-sectional view of an example of a triple-flow, twin-body propulsion system in which the fan section is unfaired.

[0013] Fig. 5 is a schematic, partial, cross-sectional view of an example of a twin-body, dual-flow propulsion system in which the blower section is unfaired, the propulsion system being fixed to a mast.

[0014] Fig. 6 is a schematic and partial view of an example of a device for attaching an aeronautical propulsion system to a mast.

[0015] Fig. 7 is a schematic, partial, side view of the fastening device of Fig. 6.

[0016] Fig. 8 is a schematic, partial, front view of the fastening device of Fig. 6.

[0017] Fig. 9 (a, b, and c) is a schematic view of the force transfer by the fixing device of Fig. 6.

[0018] Fig. 10 (a, b, and c) is a schematic view of the moment transfer by the fixing device of Fig. 6. DETAILED DESCRIPTION

[0019] Aircraft

[0020] An aircraft 100 is a device configured to rise and move through the air, and may, for example, be a civil or military airplane, or even a helicopter. An aircraft 100 comprises an airframe (or "airframe" in Anglo-Saxon terminology) which, in the case of an airplane, consists of a fuselage, a wing comprising two wings, tail assemblies, flight controls, and landing gear.

[0021] Propulsion system

[0022] A propulsion system 1 has a principal direction along a longitudinal axis X along which the propulsion system 1 extends. The propulsion system 1 is an aeronautical propulsion system 1 configured to be attached to the airframe of the aircraft 100 by means of a pylon 40 (or mast 40), which is fixed to the airframe of the aircraft 100.

[0023] In the present description, an axial direction corresponds to the direction of the longitudinal axis X, and a radial direction is a direction perpendicular to and passing through the longitudinal axis X. Furthermore, a circumferential (or lateral, or tangential) direction corresponds to a direction perpendicular to and not passing through the longitudinal axis X. Unless otherwise specified, the terms "internal" (or "inside") and "external" (or "outside") are used with reference to a radial direction such that the internal part or face of an element is closer to the longitudinal axis X than the external part or face of the same element.

[0024] The propulsion system 1 comprises, from upstream to downstream in the direction of the gas flow in the propulsion system 1 when in operation, a blower section 2 and a generator 3, 34, often called a "gas generator", which includes a primary body 3. The primary body 3 is centered on the longitudinal axis X, and includes a compressor section 4, 5, a combustion chamber 6, and a turbine section 7, 8.

[0025] The blower section 2 comprises at least one rotor 9 adapted to be driven in rotation, about the longitudinal axis X, relative to a stator portion 19e of the propulsion system 1, by the generator 3, 34. In this way, an airflow F is drawn into the propulsion system 1. Each rotor 9 of the blower section 2 comprises a hub 13 and blades 14 extending radially from the hub 13. The blades 14 of each rotor 9 may be fixed relative to the hub 13 or have variable pitch. In this case, the root of the blades 14 of each rotor 9 is pivotally mounted about a pitch axis and is connected to a pitch-changing mechanism 15 mounted in the propulsion system 1, the pitch being adjusted according to the flight phases by the pitch-changing mechanism 15.

[0026] The fan section 2 may further include a stator 16, or rectifier, which comprises blades 17 mounted on a stator hub 16 and whose function is to rectify an airflow F2, F21 flowing from the rotor 9. The stator blades 17 may be fixed relative to the stator hub 16 or have variable pitch. If so, and similarly to the rotor blades 14 9, the base of the stator blades 17 16 is pivotally mounted about a pitch axis and is connected to a pitch-changing mechanism 15a, which is generally separate from that of the rotor 9, the pitch being adjusted according to the flight phases by the pitch-changing mechanism 15a. The stator hub 16 may be fixed to a stator portion 19e of the propulsion system 1.

[0027] The blower section 2 can be shrouded or unshrouded.

[0028] In the case of a shrouded blower section 2, the blower section 2 comprises a blower housing 12, centered on the longitudinal axis X, and the rotor 9 is housed in the blower housing 12. A shrouded blower section 2 comprises a rotor 9 extending upstream of a stator 16. The blades 17 of the stator 16 are then generally called "outlet blades" (or "OGV", for "Outlet Guide Vane" in Anglo-Saxon terminology) and have a fixed position relative to the hub of the stator 16.

[0029] In the case of an unfaired fan section 2, the fan section 2, which may also be referred to as the "propeller," is not enclosed by a fan casing. The blades 14 of the rotor 9 also have variable pitch. Propulsion systems 1 comprising at least one unfaired rotor 9 are known, in Anglo-Saxon terminology, as "open rotor" or "unducted fan." The propulsion system 1 may comprise two unfaired, counter-rotating rotors 9. Such a propulsion system 1 is known, in Anglo-Saxon terminology, by the acronym "CROR" for "Contra-Rotating Open Rotor" or "UDF" for "Unducted Double Fan." The rotors 9 can be placed at the rear of the generator 3, 34 so as to be of the pusher type or at the front of the generator 3, 34 so as to be of the tractor type.Alternatively, the propulsion system 1 may comprise a single unshod rotor 9 and an unshod stator 16 (rectifier). Such a propulsion system 1 is known, in Anglo-Saxon terminology, by the acronym . "USF" stands for "Unducted Single Fan." In the case of a USF-type propulsion system 1, the blades 17 of the rectifier 16 are fixed relative to the stator portion 19e of the propulsion system 1 and, consequently, are not subjected to centrifugal force. The blades 17 of the rectifier 16 also have variable pitch. Removing the fairing around the fan section 2 allows for a significantly increased bypass ratio of the propulsion system 1 without the propulsion system 1 being negatively impacted by the mass of the housings 12 or nacelles intended to surround the fan section 2.

[0030] The compressor section 4, 5 comprises a series of stages, each including a rotating blade wheel (rotor) 4a, 5a in front of a fixed blade wheel (stator) 4b, 5b. The turbine section 7, 8 also comprises a series of stages, each including a fixed blade wheel (stator) 7b, 8b behind which a rotating blade wheel (rotor) 7a, 8a rotates.

[0031] In a twin-spool propulsion system 1, the compressor section 4, 5 comprises a low-pressure compressor 4 and a high-pressure compressor 5, and the turbine section 7, 8 comprises a high-pressure turbine 7 and a low-pressure turbine 8. The rotor stages 5a of the high-pressure compressor 5 are driven in rotation by the rotor stages 7a of the high-pressure turbine 7 via a high-pressure shaft 10. The rotor stages 4a of the low-pressure compressor 4 and the rotor 9 of the blower section 2 are driven in rotation by the rotor stages 8a of the low-pressure turbine 8 via a low-pressure shaft 11. Thus, the primary body 3 comprises a high-pressure body including the high-pressure compressor 5, the high-pressure turbine 7, and the high-pressure shaft 10, and a low-pressure body including the blower section 2, the low-pressure compressor 4, the low-pressure turbine 8, and the shaft low pressure 11.The rotational speed of the high-pressure body is greater than the rotational speed of the low-pressure body.

[0032] In a three-spool propulsion system 1, the turbine section 7, 8 further comprises an intermediate turbine, positioned between the high-pressure turbine 7 and the low-pressure turbine 8, and whose rotor stages are configured to drive the rotor stages 4a of the low-pressure compressor 4 via an intermediate shaft. The rotor 9 of the blower section 2, on the one hand, and the rotor stages 5a of the high-pressure compressor 5, on the other hand, remain driven by the low-pressure shaft 11 and the high-pressure shaft 10, respectively.

[0033] The low-pressure shaft 11 is generally housed, along a portion of its length, within the high-pressure shaft 10 and is coaxial with the high-pressure shaft 10. The low-pressure shaft 11 and the high-pressure shaft 10 may be co-rotating, that is, driven in the same direction around the longitudinal axis X. Alternatively, the low-pressure shaft 11 and the high-pressure shaft 10 may be counter-rotating, that is, driven in opposite directions around the longitudinal axis X. In any case, The high-pressure shaft 10 and the low-pressure shaft 11 each extend along the longitudinal axis X. If necessary, the intermediate shaft is housed between the high-pressure shaft 10 and the low-pressure shaft 11. The intermediate shaft and the low-pressure shaft 11 may be co-rotating or contra-rotating.

[0034] The rotor 9 of the fan section 2 can be decoupled from the low-pressure shaft 11 by means of a reduction mechanism 19, placed between the low-pressure shaft 11 and the rotor 9, in order to independently optimize their respective rotational speeds. In this case, the propulsion system 1 further includes an additional shaft 20 (or fan shaft 20). The low-pressure shaft 11 connects the rotor stages 8a of the low-pressure turbine 8 to an inlet of the reduction mechanism 19, while the fan shaft 20 connects the outlet of the reduction mechanism 19 to the rotor 9 of the fan section 2. The rotor 9 of the fan section 2 is therefore driven by the low-pressure shaft 11 via the reduction mechanism 19 and the fan shaft 20 at a rotational speed lower than the rotational speed of the low-pressure turbine 8.This decoupling makes it possible to reduce the rotational speed and pressure ratio of the rotor 9 of the blower section 2 and to increase the power extracted by the low pressure turbine 8.

[0035] The reduction mechanism 19 may include an epicycloidal (or "planetary" in Anglo-Saxon terminology) or planetary (or "star" in Anglo-Saxon terminology) reduction mechanism, single-stage or two-stage.

[0036] The rotor 9 of the blower section 1 can, alternatively, be directly coupled to the low-pressure shaft 11 (or "direct-drive" in Anglo-Saxon terminology), i.e. without a reduction mechanism 19. The low-pressure shaft 11 is then combined with the blower shaft 20 so that the rotor 9 is driven by the low-pressure shaft 11 at the same rotational speed as that of the rotor stages 8a of the low-pressure turbine 8.

[0037] In operation, the airflow F entering the propulsion system 1 is divided, by an annular nozzle 300 of the primary body 3, between a primary airflow Fl and a secondary airflow F2, which circulate from upstream to downstream in the propulsion system 1.

[0038] The primary airflow Fl flows in a primary channel 29 defined by the primary body 3, passing successively through the compressor section 4, 5, the combustion chamber 6 where it is mixed with fuel to serve as an oxidizer, and the turbine section 7, 8. The passage of the primary airflow Fl through the turbine section 7, 8 receiving energy from the combustion chamber 6 causes a rotation of the rotor stages 7a, 8a of the turbine section 7, 8, which in turn drives the rotation of the rotor stages 4a, 5a of the compressor section 4, 5 as well as the rotor 9 of the blower section 2.

[0039] The secondary airflow F2, also called the "bypass airflow", flows around the primary body 3. The secondary airflow F2 cools the periphery of the primary body 3 and is used to generate most of the thrust provided by the propulsion system 1.

[0040] In a dual-flow propulsion system 1, the secondary airflow F2 provides both the cooling function and the thrust function.

[0041] In a triple-flow propulsion system, the generator 3, 34 comprises a secondary body 34, also centered on the longitudinal axis X, which notably allows the separation of the thrust function, provided by a first secondary subflow F21, and the cooling function of the primary body 3, provided by a second secondary subflow F22. The secondary flow F2 is divided into the first secondary subflow F21 and the second secondary subflow F22 by an annular nozzle 340 of the secondary body 34. The annular nozzle 340 of the secondary body 34 is positioned axially between the rotor 9 of the fan section 2 and the annular nozzle 300 of the primary body 3. The secondary body 34 defines with the primary body 3 a secondary channel 35 in which the second secondary subflow F22 flows. To facilitate the cooling of the primary body 3, a heat exchanger 36 can extend within the secondary vein 35.Furthermore, the generator 3, 34 of a triple-flow propulsion system 1 may include an intermediate propeller 37 positioned between the annular nozzle 340 of the secondary body 34 and the annular nozzle 300 of the primary body 3, and configured to propel the second secondary sub-flow F22 within the secondary stream 35. The intermediate propeller 37 is driven by the rotor stages 8a of the low-pressure turbine 8, via the low-pressure shaft 11, and therefore belongs to the low-pressure body.

[0042] The generator 3, 34 includes a front casing 32 (or inlet casing 32) positioned between the annular nozzle 300, 340 and the low-pressure compressor 4. The front casing 32 is fixed relative to a stator portion 19e of the propulsion system 1. The front casing 32 can support the rotation of the low-pressure shaft 11 and / or the blower shaft 20, via bearings. The reduction mechanism 19 can also be supported by the front casing 32. The front casing 32 generally includes structural arms extending radially within the airflow between two concentric annular walls delimiting a portion of an airflow circulation channel within the generator 3, 34, the structural arms being further distributed around the longitudinal axis X.In a dual-flow propulsion system 1, the structural arms of the front casing 32 extend within the primary flow 29 and can thus perform an aerodynamic function of straightening the primary flow Fl circulating within the primary flow 29, in order to limit pressure losses. In a triple-flow propulsion system, the front casing 32 is positioned between the annular nozzle 340 of the secondary body. 34 and the intermediate propeller 37, and can then present an aerodynamic function of straightening the flow sucked in by the intermediate propeller 37. In any case, the structural arms can be hollow for the passage of servicing and / or the stator blades 17 16 can extend in the radial extension of the inlet housing 32.

[0043] The turbine section 7, 8 includes an inter-turbine housing 30, positioned between the high-pressure turbine 7 and the low-pressure turbine 8, and a rear housing 31 (or outlet housing 31) positioned downstream of the low-pressure turbine 8. The inter-turbine housing 30 and the rear housing 31 are fixed relative to the stator part 19e of the propulsion system 1. In addition, the inter-turbine housing 30 can support the rotation of the high-pressure shaft 10, while the rear housing 31 can support the rotation of the low-pressure shaft 11, via bearings. The inter-turbine casing 30 and the rear casing 31 generally each include structural arms extending radially within the primary channel 29. The structural arms then extend between two concentric annular walls defining a portion of the primary channel 29, the structural arms being further distributed all around the longitudinal axis X.The structural arms of the inter-turbine casing 30 and the rear casing 31 can, in this respect, provide an aerodynamic function for straightening the primary flow Fl circulating within the primary channel 29, in order to limit pressure losses. The structural arms can be hollow for the passage of service lines.

[0044] The generator 3, 34 includes an intermediate housing 33 (or inter-compressor housing 33) which supports the high-pressure shaft 10, the low-pressure shaft 11 and / or the intermediate shaft in rotation, via bearings. The intermediate housing 33 is fixed relative to the stator portion 19e of the propulsion system 1.

[0045] In a dual-flow propulsion system, as in a triple-flow propulsion system, the intermediate casing 33 comprises a first wall 331 and a second wall 332, preferably annular, concentric, and centered on the longitudinal axis X, the second wall 332 extending radially outside the first wall 331. The first wall 331 and the second wall 332 delimit a portion of the primary stream 29 which is positioned between the low-pressure compressor 4 and the high-pressure compressor 5. Structural arms 335, which may be hollow for the passage of service lines, extend radially from the first wall 331 to the second wall 332, being distributed all around the longitudinal axis X.

[0046] In a triple-flow propulsion system, the intermediate casing 33 further comprises a third wall 333 and a fourth wall 334, preferably annular, concentric, and centered on the longitudinal axis X, the fourth wall 334 extending radially outside the third wall 333. The third wall 331 and the fourth wall 332 delimit a portion 351 of the secondary flow 35. Structural arms 336, which may be hollow for the passage of service lines, extend radially from the third wall 333 to the fourth wall 334, being distributed all around the longitudinal axis X. The structural arms 336 of the intermediate casing 33 extend into the secondary vein 35 and can then have an aerodynamic function of straightening the primary flow of the second secondary subflow F22 circulating within the secondary vein 35, which helps to limit pressure losses.

[0047] Attachment to the pylon

[0048] The stator 16 and, where applicable, the casing 12 of the blower section 2, the front casing 32, the intermediate casing 33, the stator stages 4b, 5b of the compressor section 4, 5, the stator stages 7b, 8b, the inter-turbine casing 30 and the rear casing 31 of the turbine section 7, 8, and the stator part 19e of the propulsion system 1 are fixed to each other and to the pylon 40, once the propulsion system 1 is fixed to the pylon 40.

[0049] To do this, a fastening system 51, 52, 53 connects the propulsion system 1 to the pylon 40 in an isostatic manner, that is to say in a configuration in which the mechanical links connecting the propulsion system 1 and the pylon 40, in particular the support reactions, can be fully determined from the equations of statics: the number of unknowns of mechanical linkage is equal to the number of equations given by the principle of equilibrium of statics. In other words, the fundamental principle of dynamics is sufficient to determine all the constraints of the connection between the propulsion system 1 and the pylon 40. Thus, it is possible to directly solve for the forces and moments (or torques) acting on the assembly formed by the propulsion system 1 and the pylon 40. This method of attachment is preferable, compared to a statically indeterminate attachment, for making it easier to predict the stresses circulating within the assembly during mounting on the aircraft 100.

[0050] The fastening system 51, 52, 53 comprises a first fastening device 51 connecting the propulsion system 1 to the pylon 40. The first fastening device 51 is configured to resist only torsional moments about the longitudinal axis X. Thus, the first fastening device 51 allows any translation of the propulsion system 1 relative to the pylon 40, whether along the longitudinal axis X or along an axis radial to the longitudinal axis X. Furthermore, the first fastening device 51 allows any rotation of the propulsion system 1, relative to the pylon 40, about an axis radial to the longitudinal axis X. Conversely, the first fastening device 51 prohibits any rotation of the propulsion system 1, relative to the pylon 40, about the longitudinal axis X.Dedicating a fixing device 51 to the transfer of torsional stresses around the longitudinal axis X, rather than transferring these stresses using two fixing points positioned axially at a distance from each other, makes it possible to limit the transfer of these stresses by the longitudinal structures of the system. Propulsion System 1. This stress transfer is nevertheless necessary to prevent play from developing within the mechanical parts of propulsion system 1 and / or stress from accumulating within propulsion system 1. Depending on the overall structure of propulsion system 1 and the fastening system 51, 52, 53, it is sufficient to adapt the axial positioning of the first fastening device 51. Therefore, it is no longer necessary to oversize the longitudinal structures of propulsion system 1 and / or to provide circumferential structures to ensure the transfer of these stresses. A significant reduction in mass and maintenance time is thus achieved.

[0051] In one embodiment, the first fastening device 51 comprises a coupling element 510, a pivot joint 511, a first connecting rod 512, a first ball joint 513, a second ball joint 514, a second connecting rod 515, a third ball joint 516, and a fourth ball joint 517. The pivot joint 511 connects the coupling element 510 to the pylon 40. The first ball joint 513 connects the first connecting rod 512 to the coupling element 510. The second ball joint 514 connects the first connecting rod 512 to the propulsion system 1. The third ball joint 516 connects the second connecting rod 515 to the coupling element 510. The fourth ball joint 517 connects the second connecting rod 515 to the propulsion system 1.

[0052] The coupling element 510 comprises a body 5100 and an arm 5101. The body 510 is connected to the pylon 40 by the pivot joint 511. The arm 5101 extends in a direction transverse to the longitudinal axis X, i.e., perpendicular to the longitudinal axis X and to an axis radial to the longitudinal axis X. The arm 5101 is connected to the first connecting rod 512 by the first ball joint 513 and to the second connecting rod 515 by the third ball joint 516.

[0053] The pivot joint 511 comprises a set of parts cooperating to guide the rotation of the coupling element 510, and more specifically its body 5100, by allowing it to rotate only about a connecting axis that extends transversely to the longitudinal axis X, that is, perpendicularly to the longitudinal axis X and to an axis radial to the longitudinal axis X. Among these parts is an axle 5110, fixed to the pylon 40, and extending along the connecting axis of the pivot joint 511. The axle 5110 cooperates with one end of the coupling element 510, and more specifically of the body 5100, which is opposite the propulsion system 1, and more specifically opposite the arm 5101, and has a shape adapted to complete the pivot joint 511. The body 5100 is thus pivotally mounted on the axis 5110. The axis 5110 extends parallel to the arm 5101, being axially offset from the arm 5101.In this way, the first fixing device 51 allows movement of the propulsion system 1 relative to the pylon 40 in a radial direction which passes through the propulsion system 1 and the pylon. 40, that is, in a vertical direction. In other words, this configuration of the coupling element 510 and the pivot joint 511 allows the first fixing device 51 to avoid absorbing vertical forces transmitted between the propulsion system 1 and the pylon 40. In this respect, the body 5100 is sufficiently rigid not to deform when the propulsion system 1 is subjected to a vertical movement relative to the pylon 40.

[0054] Each connecting rod 512, 515 is an elongated part which preferably takes the form of a rigid rod, but which can also take the form of a telescopic rod, and which is configured to transmit movement between two articulated elements ("hinged" in Anglo-Saxon terminology), in this case by means of the ball joints 513, 514, 516, 517, at its ends.

[0055] Each ball joint 513, 514, 516, 517 comprises a set of cooperating parts to prohibit any translation between the elements it connects, but to allow any rotation between these elements. The ball joints 513, 514, 516, 517 allow the propulsion system 1 to be articulated on the coupling element 510, and more specifically on the arm 5101, so as to allow any translation of the propulsion system 1 relative to pylon 40 in a direction perpendicular to the vertical direction, but also any rotation of the propulsion system 1 relative to the pylon around an axis radial to the longitudinal axis X. In addition, the second ball joint 514 and the fourth ball joint 517 are positioned on either side of a plane of axial symmetry of the assembly formed by the propulsion system 1 fixed to the pylon 40 which includes the longitudinal axis X, i.e. a vertical plane.In this way, the first fixing device 51 prevents any rotation of the propulsion system 1, relative to the pylon 40, around the longitudinal axis X, one of the connecting rods 512, 515 being loaded in compression while the other is loaded in tension. In other words, the first fixing device 51 resists the torsional moments about the longitudinal axis X. The relative positioning of the second ball joint 514 and the fourth ball joint 517, with respect to the vertical plane, can be adjusted according to the intensity of the stresses to be resisted and / or the desired dimensions. The second ball joint 514 and the fourth ball joint 517 can, in this respect, be positioned equidistant from the vertical plane.

[0056] Furthermore, the fastening system 51, 52, 53 may include a second fastening device 52 connecting the propulsion system 1 to the pylon 40. The second fastening device 52 is configured to resist only the forces, and not the moments, circulating between the propulsion system 1 and the pylon 40. In other words, the second fastening device 52 allows any rotation of the propulsion system 1 relative to the pylon 40, but prohibits any translation of the propulsion system 1 relative to the pylon 40. In this respect, the second fastening device 52 may including a connecting rod extending parallel to the vertical plane and having a first end pivotally mounted on the pylon 40 and a second end pivotally mounted on the propulsion system 1. In addition, the second fastening device 52 may include a spigot extending out of the propulsion system 1 and cooperating with a corresponding fastening element attached to the pylon 40.

[0057] Furthermore, the fastening system 51, 52, 53 may include a third fastening device 53 connecting the propulsion system 1 to the pylon 4. The third fastening device 53 is configured to resist only the radial forces circulating between the propulsion system 1 and the pylon 40. In other words, the third fastening device 53 allows a translation of the propulsion system 1 relative to the pylon 40 along the longitudinal axis X and any rotation of the propulsion system 1 relative to the pylon 40, but prohibits any translation of the propulsion system 1 relative to the pylon 40 along an axis radial to the longitudinal axis X. In this respect, the third fastening device 53 may include a yoke articulated on the propulsion system 1 and fixed to the pylon 40.

[0058] Since the third fastening device 53 is axially offset relative to the second fastening device 52, the combination of their properties allows the fastening system 51, 52, 53 to resist torsional moments about a radial axis to the longitudinal axis X, i.e., to prevent any rotation about a radial axis to the longitudinal axis X. If necessary, the first fastening device 51 is positioned axially between the second fastening device 52 and the third fastening device 53. In this way, the torsional stresses about the longitudinal axis X do not pass through the longitudinal structures of the propulsion system 1. Furthermore, the further the second fastening device 52 is axially from the third fastening device 53, the more important the presence of the first fastening device 51, interposed axially between the second fastening device 52 and the third fastening device 53.

[0059] In one embodiment, the first fastening device 51 connects the front housing 12 and / or the intermediate housing 33 to the pylon 40, thus allowing any translation of the front housing 12 and / or the intermediate housing 33 relative to the pylon 40 and any rotation of the front housing 12 and / or the intermediate housing 33 about an axis radial to the longitudinal axis X, and prohibiting any rotation of the front housing 12 and / or the intermediate housing 33 about the longitudinal axis X. More specifically, the first fastening device 51 thus connects the pylon 40 to an external annular wall of the front housing 12, to an external annular wall of the intermediate housing 33, and / or to an external annular wall common to the front housing 12 and the intermediate housing 33. Where applicable, the second ball joint 514 and the fourth ball joint 517 connect, respectively, the first connecting rod 512 and the second connecting rod 515, to the front crankcase 12 and / or the intermediate crankcase 33, preferably to the outer annular wall of the front crankcase 12, to the outer annular wall of the intermediate crankcase 33, and / or to the outer annular wall common to the front crankcase 12 and the intermediate crankcase 33.

[0060] In one embodiment, the second fastening device 52 connects the front casing 12 and / or the intermediate casing 33 to the pylon 40, allowing any rotation of the front casing 12 and / or the intermediate casing 33 relative to the pylon 40, and prohibiting any translation of the front casing 12 and / or the intermediate casing 33 relative to the pylon 40. More specifically, the second fastening device 52 thus connects the pylon 40 to the outer annular wall of the front casing 12, to the outer annular wall of the intermediate casing 33, and / or to the outer annular wall common to the front casing 12 and the intermediate casing 33.Where applicable, the second end of the connecting rod of the second fastening device 52 is pivotally mounted on the front housing 12 and / or the intermediate housing 33, preferably on the outer annular wall of the front housing 12, on the outer annular wall of the intermediate housing 33, and / or on the outer annular wall common to the front housing 12 and the intermediate housing 33. Similarly, the lug extends projecting from the front housing 12 and / or the intermediate housing 33, preferably from the outer annular wall of the front housing 12, from the outer annular wall of the intermediate housing 33, and / or from the outer annular wall common to the front housing 12 and the intermediate housing 33.

[0061] The fastening system 51, 52, 53 can connect the propulsion system 1 to the pylon 40 so that the generator 3, 34 is cantilevered (or "cantilever core" in Anglo-Saxon terminology) relative to the pylon 40. In this configuration, the generator 3, 34 comprises a first part 301 which the fastening system 51, 52, 53 connects to the pylon 40 isostatically, and a second part 302 which extends from the first part 301 to an end 303 axially opposite the rotor 9 of the fan section 2, the end 303 being left movable relative to the pylon 40. This fastening of the propulsion system 1 to the pylon 40 limits the deformations of the second part 302 of the generator 3, 34. Indeed, in this configuration, the structural stresses suffered by the propulsion system 1 are transmitted preferentially through the first part 301 of the generator 3, 34 and not through the second part 302 of the generator 3, 34.This is all the more advantageous as the second part 302 of generator 3, 34 has small radial dimensions compared to the radial dimensions of the first part 301 of generator 3, 34.

[0062] The propulsion system 1 may further include a tubular support 60 extending axially from the intermediate casing 33 to the end 303 of the second part 302 of the generator 3, 34, which is movable relative to the pylon 40. The tubular support 60 is centered on the longitudinal axis 40 and surrounds the second part 302 of the generator 3, 34, that is to say that it extends all around the second part 302 in a circumferential direction.

[0063] In one embodiment, the third fastening device 53 connects the tubular support 60 to the pylon 40, allowing translation of the tubular support 60, relative to the pylon 40, along the longitudinal axis X and any rotation of the tubular support 60 relative to the pylon 40, but prohibiting any translation of the tubular support 60, relative to the pylon 40, along an axis radial to the longitudinal axis X. Where applicable, the bracket of the third fastening device 53 is articulated on the tubular support 60. Preferably, the third fastening device 53, in particular the bracket, is positioned axially as close as possible to the end 303 of the second part 302 which is movable relative to the mast 40 and, moreover, also movable relative to the tubular support 60.

[0064] The first part 301 of the generator 3, 34 may include the inlet casing 32, the low-pressure compressor 4, the intermediate casing 33, and the tubular support 60, while the second part 302 of the generator 3, 34 may include the high-pressure compressor 5, the combustion chamber 6, and the turbine section 7, 8. The second part 302 of the generator 3, 34 then has radial dimensions that are all the smaller compared to the radial dimensions of the first part 301 of the generator 3, 34 because the primary body 3 has high efficiency, typically through acceleration of the high-pressure body and / or the low-pressure body, which allows for an advantageous gain in compactness. Furthermore, the downstream end 303 of the turbine section 7, 8 forms the cantilevered free end 303 of the generator 3, 34.

[0065] The second part 302 of the generator 3, 34 is, in particular, subjected to loads related to the maneuvers of the aircraft 100 in flight. These loads are all the more significant as auxiliary structures, such as an electric generator for the hybridization of the propulsion system 1, an accessory housing and / or a lubrication fluid reservoir, may also be attached to the primary body 3. Such loads can cause relative displacements between the second part 302 of the generator 3, 34 and the first part 301 of the generator 3, 34, typically relative displacements transverse to the longitudinal axis X, and this in proportions which may prove problematic for the proper mechanical integrity of the propulsion system 1.

[0066] In order to limit such relative displacements, the propulsion system 1 may include a centering system 70 configured to allow movement of the second part 302 of the generator 3, 34 relative to the first part 301 of the generator 3, 34, along the longitudinal axis, and to prevent any movement of the second part 302 of the generator 3, 34 relative to the first part 301 of the generator 3, 34, transversely to the longitudinal axis X. The centering system 70 may include a plurality of connecting rods articulated on the tubular support 60 and the outlet housing 31. The centering system 70 thus limits deformations under aircraft maneuvering loads 100.

[0067] Thanks to the fastening system 51, 52, 53, the torsional stresses around the longitudinal axis X, which may be linked in particular to the aerodynamic forces and / or moments resulting from the flow asymmetry on the rotor 9 of the fan section 2, especially when the latter is unfaired, are effectively absorbed, without penalizing the mass and / or maintenance of the propulsion system 1. Indeed, the tubular support 60, and in particular its longitudinal structural parts, is no longer loaded in shear and it is therefore no longer necessary to equip it with external hemispherical panels attached to the longitudinal structural parts, which limit access to the primary body 3 during maintenance of the propulsion system 1.The fastening system 51, 52, 53 also allows other torsional stresses to be taken up around the longitudinal axis X, typically the torque forces exerted by the stator blades 17 of the fan section 2, the forces passing through the reduction mechanism 19 from the low pressure shaft 11, and / or the forces related to transient events, such as the ingestion of a bird or the loss of a blade 14 of the rotor 9 of the fan section 2. Thus, the operating clearances within the propulsion system 1 are controlled.

Claims

Demands

1. Assembly comprising: a pylon (40) configured to be fixed to an aircraft cell (100); an aeronautical propulsion system (1) extending along a longitudinal axis (X); and a fastening system (51, 52, 53) connecting the aeronautical propulsion system (1) to the pylon (40) in an isostatic manner, the fastening system (51, 52, 53) comprising a first fastening device (51) connecting the aeronautical propulsion system (1) to the pylon (40), permitting any translation of the aeronautical propulsion system (1) relative to the pylon (40) and any rotation of the aeronautical propulsion system (1), relative to the pylon (40), around an axis perpendicular to the longitudinal axis (X), and prohibiting any rotation of the aeronautical propulsion system (1), relative to the pylon (40), around the longitudinal axis (X).

2. Assembly according to claim 1, wherein the fastening system (51, 52, 53) further comprises: a second fastening device (52) connecting the aeronautical propulsion system (1) to the pylon (40), permitting any rotation of the aeronautical propulsion system (1) relative to the pylon (40), and prohibiting any translation of the aeronautical propulsion system (1) relative to the pylon (40); and a third fastening device (53) connecting the aeronautical propulsion system (1) to the pylon (40), permitting a translation of the aeronautical propulsion system (1) relative to the pylon (40) along the longitudinal axis (X) and any rotation of the aeronautical propulsion system (1) relative to the pylon (40), and prohibiting any translation of the aeronautical propulsion system (1) relative to the pylon (40) along an axis perpendicular to the longitudinal axis (X);and in which the first fastening device (51) is positioned axially between the second fastening device (52) and the third fastening device (53).

3. An assembly according to any one of claims 1 and 2, wherein the aeronautical propulsion system (1) comprises: a blower rotor (9) configured to draw in an airflow (F); and a generator (3, 34) configured to drive the blower rotor (9), and comprising a first part (301) and a second part (302) extending from the first part (301) to an end (303) axially opposite to the blower rotor (9); wherein the fastening system (51, 52, 53) connects the first part (301) of the generator (3, 34) to the pylon (40) isostatically, leaving the end (303) of the second part (302) of the generator (3, 34) movable relative to the pylon (40).

4. Assembly according to claim 3, wherein the aeronautical propulsion system (1) comprises a fan shaft (11, 20) driving the fan rotor (9), and the generator (3, 34) comprises a drive shaft (11) configured to drive the fan shaft (11, 20); wherein the first part (301) of the generator (3, 34) of the aeronautical propulsion system (1) comprises a housing (32, 33) supporting the fan shaft (11, 20) and the drive shaft (11); and in which the first fixing device (51) connects the casing (32, 33) to the pylon (40), permits any translation of the casing (32, 33) relative to the pylon (40) and any rotation of the casing (32, 33) around an axis perpendicular to the longitudinal axis (X), and prohibits any rotation of the casing (32, 33) around the longitudinal axis (X).

5. Assembly according to claim 4, where claim 3 depends on claim 2, wherein the second fastening device (52) connects the housing (32, 33) to the pylon (40), permits any rotation of the housing (32, 33) relative to the pylon (40), prohibits any translation of the housing (32, 33) relative to the pylon (40), and is positioned axially between the blower rotor (9) and the first fastening device (51).

6. An assembly according to claim 5, wherein the first part (301) of the generator (3, 34) of the aircraft propulsion system (1) comprises a tubular support (60) extending axially from the housing (32, 33) to the end (303) of the second part (302) of the generator (3, 34), which is movable relative to the pylon (40), the tubular support (60) surrounding the second part (302), the end (303) of the second part (302), movable relative to the pylon (40), being further movable relative to the tubular support (60), and the third fastening device (53) connecting the tubular support (60) to the pylon (40), allowing translation of the tubular support (60) relative to the pylon (40) along the longitudinal axis (X) and any rotation of the tubular support (60) relative to the pylon (40), and prohibiting any translation of the tubular support (60) relative to the pylon (40) along an axis perpendicular to the longitudinal axis (X).

7. Assembly according to any one of claims 1 to 6, wherein the first fastening device (51) of the fastening system (51, 52, 53) comprises a coupling element (510), a pivot joint (511) connecting the coupling element (510) to the pylon (40), a first connecting rod (512), a first ball joint (513) connecting the first connecting rod (512) to the coupling element (510), a second ball joint (514) connecting the first connecting rod (512) to the aeronautical propulsion system (1), a second connecting rod (515), a third ball joint (516) connecting the second connecting rod (515) to the coupling element (510), and a fourth ball joint (517) connecting the second connecting rod (515) to the aeronautical propulsion system (1).

8. Assembly according to claim 7, wherein the coupling element (510) of the first fastening device (51) of the fastening system (51, 52, 53) comprises a body (5100) connected to the pylon (40) by the pivot joint (511), and an arm (5101) extending in a direction perpendicular to the longitudinal axis (X) and in a direction radial to the longitudinal axis (X), connected to the first connecting rod (512) by the first ball joint (513) and to the second connecting rod (515) by the third ball joint (516); and in which the pivot joint (511) of the first fixing device (51) comprises an axis (5110) fixed to the pylon (40) and extending parallel to the arm (5101) of the coupling element (510) being axially offset with respect to the arm (5101), the body (5100) of the coupling element (510) being pivotally mounted on the axis (5110).

9. Assembly according to any one of claims 7 and 8, wherein the aeronautical propulsion system (1) and the pylon (40) have a common axial symmetry plane which includes the longitudinal axis (X), the second ball joint (514) and the fourth ball joint (517) of the first fastening device (51) of the fastening system (51, 52, 53) being positioned on either side of the common axial symmetry plane.

10. Aircraft (100) comprising a cell and an assembly according to any one of claims 1 to 9, wherein the pylon (40) of the assembly is fixed to the cell.

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