AIRCRAFT TURBOMACHINE SUSPENSION SYSTEM WITH BALL JOINT AND SLIDING PIVOT LINKAGE

Abstract

This aircraft turbomachine suspension system comprises a set of connecting rods (25), each including linkage means (26, 27) for attaching the system between a turbomachine housing (22, 23) and an aircraft component. The linkage means include a ball joint (26) and a sliding pivot joint (27). See Figure 4 for abbreviations.

Description

Title of the invention: SUSPENSION SYSTEM FOR AIRCRAFT TURBOMACHINES WITH BALL JOINT AND SLIDING PIVOT LINKAGE technical field

[0001] The present invention relates to the field of turbomachines used for the propulsion of an aircraft and, more particularly, the attachment of a turbomachine to an element of the aircraft. Previous techniques

[0002] In a known manner, a turbomachine is intended to provide the thrust necessary for the propulsion of an aircraft. It classically comprises, from upstream to downstream, considering the direction of an airflow admitted into the turbomachine, a fan allowing to accelerate the airflow admitted into the turbomachine and comprising blades generally extending in the same plane transverse to the axis of the turbomachine, at least one compressor, a combustion chamber and at least one turbine to drive the compressor in rotation.

[0003] Attaching an aircraft turbomachine to an aircraft component is carried out in the prior art by means of a suspension system comprising a clevis including load-bearing connecting rods fixed on one side to a turbomachine casing and on the other side to a coupling fixed to a pylon linked to the aircraft component.

[0004] An example of an embodiment of such a suspension system is illustrated in [Fig. 1] which illustrates an aircraft turbomachine, designated by the numerical reference 1, comprising a casing 2, for example an inter-compressor casing, which is suspended from a mounting pylon 3 by means of a set of straight or boomerang-shaped connecting rods 4 linked by ball joints, such as 5, to the casing 2, on the one hand and to a coupling 6 fixed to the pylon 3, on the other hand.

[0005] According to another arrangement visible in figures 2 and 3, the turbomachine casing 2 is suspended by means of a set of centering rods 7 comprising a first end 8 connected by a ball joint to the turbomachine casing 2 and an opposite end 9 connected by a ball joint to a nacelle 10 connected to the mounting pylon 3.

[0006] In [Fig. 3], which corresponds to the embodiment of [Fig. 2], the turbomachine's suspension system is attached to the exhaust housing or TRF (TRF being the Anglo-Saxon acronym for "Turbine Rear Frame") of the turbomachine. The TRF housing comprises an inner ferrule 11 and an outer ferrule 12, the suspension system comprising centering rods 7 connected to the outer ferrule 12 and to the nacelle.

[0007] In aircraft turbomachinery, it is generally desirable to constrain the transverse translations, i.e. perpendicular to the axis of the engine, and the rolling moment, coaxial with the engine of the turbomachine casing with respect to the pylon.

[0008] Suspension systems according to the prior art are likely to generate undesirable stresses in the turbomachine casing, particularly under the action of the connecting rods, these stresses being likely to cause casing ovalization, eccentricity of the load-bearing bearings, or even localized punching of the casing. Description of the invention

[0009] The aim of the invention is therefore to overcome these disadvantages and to propose a suspension system for aircraft turbomachinery that reduces stresses in the casing.

[0010] The invention therefore relates to a suspension system for an aircraft turbomachine, comprising a set of connecting rods, each comprising means for attaching the system between a housing of the turbomachine and an element of the aircraft.

[0011] The connecting means include a ball joint and a sliding pivot joint.

[0012] In one embodiment, each connecting rod includes at one end a connection ball joint and at one opposite end a sliding pivot joint.

[0013] According to a feature of the suspension system according to the invention, the sliding axis of the sliding pivot joint is inclined with respect to a general axis of the turbomachine.

[0014] Advantageously, the sliding axis is inclined at an angle (a) related to the axial displacement Uaxial(t) and the radial displacement Uradial(t) of a downstream end of the connecting rod by the relation:

[0015] Uradial (t) = A+sin (a), Uaxial (t)

[0016] in which A is a constant independent of the angle of inclination of the sliding pivot joint and of the axial and radial displacements, representing an original value of the radial displacement.

[0017] Advantageously, the suspension system includes damping means.

[0018] The sliding pivot joint may also include a stop to limit the sliding of the connecting rod.

[0019] The invention also relates to an aircraft turbomachine comprising a suspension system as defined above. Brief description of the drawings

[0020] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0021] Figs.1,2 and3, which have already been mentioned, schematically illustrate a turbomachine equipped with a suspension system according to the prior art;

[0022] Figure 4 schematically illustrates a turbomachine equipped with a suspension system according to the invention; and

[0023] Figure 5 illustrates an example of the implementation of damping means integrated into the suspension system. Detailed description of at least one embodiment

[0024] Reference will be made to [Fig.4] which illustrates a turbomachine 20 equipped with a suspension system 21 according to the invention.

[0025] The invention relates essentially to the suspension system, only the part of the turbomachine 20 to which the suspension system is attached has been illustrated in [Fig.4],

[0026] A turbomachine extends along a turbomachine axis X and allows an aircraft to be propelled from an airflow entering the turbomachine and circulating from upstream to downstream, the terms upstream and downstream being defined with respect to the turbomachine axis X, considering the direction of the airflow in the turbomachine.

[0027] In a known manner, the turbomachine comprises, from upstream to downstream, a blower and a gas generator comprising a low pressure compressor, a high pressure compressor, a combustion chamber, a high pressure turbine and a low pressure turbine.

[0028] The low-pressure compressor, together with the low-pressure turbine to which it is connected by a turbine shaft, forms a low-pressure (LP) unit that drives the blower in rotation. The high-pressure compressor, together with the high-pressure turbine to which it is connected by a shaft, forms a high-pressure (HP) unit.

[0029] The fixed structural components of the turbomachine include in particular an inlet casing located at the inlet of the gas generator, an inter-compressor casing, located between the low pressure compressor and the high pressure compressor, and a TRF exhaust casing directly at the outlet of the low pressure turbine.

[0030] The turbomachine is supported by a suspension system 21 attached to the turbomachine housing, in particular to the TRF housing comprising an inner ferrule 22 and an outer ferrule 23, and to the nacelle 24 attached to an element of the aircraft, for example under a wing.

[0031] The suspension system comprises a set of centering rods, such as 25, arranged between the turbomachine and the aircraft element, in particular between the TRF housing of the turbomachine and the nacelle and regularly distributed around the turbomachine.

[0032] The nacelle 24 is a structural nacelle, in that it allows centering of the turbomachine housing by means of the centering rods 25.

[0033] The centering rods comprise, at their mutually opposite ends, means for connecting to the TRF housing and the nacelle, respectively. The connecting means comprise a ball joint 26 and a sliding pivot joint 27.

[0034] As illustrated in [Fig.4], each connecting rod includes at one end a ball joint 26, by which it is fixed to the outer ferrule of the housing, and at its opposite end a sliding pivot joint 27. The ball joint is provided here at the upstream end of the connecting rod, while the sliding pivot joint is provided at the downstream end of the connecting rod.

[0035] The axis of the sliding pivot joint is inclined at an angle α with respect to the X axis of the turbomachine chosen to synchronize the axial and radial movements of the downstream attachment of the TRF housing.

[0036] The radial displacement Uradiaide at the downstream end of the connecting rod must be approximately an affine function of the axial displacement U^ai such that:

[0037] UradiaI (t) = A+sin (a).Uaxial (t)

[0038] Where A is a constant independent of the angle of inclination of the sliding pivot joint and of the axial and radial displacements, representing an original value of the radial displacement.

[0039] For example, the orders of magnitude are 5 to 15mm for the displacement UaxiaI ( t ) and 1 to 5 mm for the radial displacement Ura<üai(0> a tolerance of 10% with respect to the affine function can be provided.

[0040] Compared to a two-ball joint connection, in which the forces applied along the axis of the connecting rod are referred back to the housing and to the aircraft element to which the suspension system is attached, a connection comprising a ball joint and a sliding pivot joint makes it possible to avoid the blocking of uniform expansions of the centering rods or differential expansions between the connecting rods, each connecting rod being free to move along the sliding pivot joint, in the axis of the joint, when the engine and the connecting rods expand thermally.

[0041] However, the axial-radial translations of the downstream end of the connecting rod are not blocked. The inclination of the sliding pivot makes the suspension system robust and reliable in the event of different axial and radial expansions, during engine heating or cooling.

[0042] With reference to [Fig.5], in one embodiment, the suspension system is advantageously equipped with damping means.

[0043] These damping means are for example fluid damping means, for example oil damping, capable of filtering high frequency loads and thus allowing the sliding pivot to take over the loads generated during aircraft maneuvers.

[0044] For example, the damping means comprise a cylinder 28 filled with oil or a suitable fluid, for example linked to the nacelle and comprising two communicating chambers between which a calibrated passage 29 is provided, and a piston 30 linked for example to a connecting rod, a return spring 31 being associated with the piston.

[0045] Advantageously, the suspension system further includes a connecting rod travel limiting stop, capable of limiting the sliding movement of the pivot joint. For example, this stop consists of a wall 32 delimiting the calibrated passage 29, against which the piston abuts at the end of its stroke. Such a stop can be provided in addition to the damping means. It can also be provided in the absence of damping means, by providing a corresponding fixed stop in the pivot joint.

[0046] It will be noted that the invention which has just been described, which uses connecting means comprising a ball joint 26 and a sliding pivot joint 27, applies to any suspension system comprising any number of centering rods.

[0047] Furthermore, the invention is not limited to a suspension system used for centering a TRF housing but also applies to other attachment points located on the housing of the turbomachine.

Claims

Demands

1. Suspension system for aircraft turbomachine, comprising a set of connecting rods (25) each comprising connecting means (26, 27) for fixing the system between a housing (22, 23) of the turbomachine and an element of the aircraft, characterized in that the connecting means comprise a ball joint (26) and a sliding pivot joint (27).

2. Suspension system according to claim 1, wherein each connecting rod (25) comprises at one end a ball joint (26) and at an opposite end a sliding pivot joint (27).

3. Suspension system according to any one of claims 1 and 2, wherein the sliding axis of the sliding pivot joint (27) is inclined with respect to a general axis (X) of the turbomachine.

4. Suspension system according to claim 3, wherein the sliding axis is inclined at an angle (a) related to the axial displacement Uaxial ( t ) and the radial displacement Uradiai ( 1 ) of a downstream end of the connecting rod (25) by the relation: ^radial ( t ) — A + Sill ( U ) .Uaxla| ( t ) where A is a constant independent of the angle of inclination of the sliding pivot joint and of the axial and radial displacements, representing an original value of the radial displacement.

5. Suspension system according to any one of claims 1 to 4, comprising damping means (28, 29, 30).

6. Suspension system according to any one of claims 1 to 5, wherein the sliding pivot joint includes a stop (32) for limiting the sliding of the connecting rod.

7. Aircraft turbomachine comprising a suspension system according to any one of claims 1 to 6.

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