Ball joint for the piping of an engine, and associated piping and aircraft
Patent Information
- Application Number
- EP2023814513
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-10-24
- Filing Date
- 2023-10-24
- Publication Date
- 2025-09-03
AI Technical Summary
Existing ball joints for engine piping, particularly in aircraft engines, fail to effectively resist temperature variations and vibrations due to lack of sufficient damping and durability, leading to premature deterioration.
A ball joint design featuring a metal bellows with a stack of at least three metal layers, providing enhanced damping through friction between layers, and an annular bearing with a friable material to facilitate relative movement and reduce thermal stress, while maintaining a watertight connection between fluid flow pipes.
The solution significantly increases the durability and lifespan of the ball joint by enhancing damping capabilities, allowing it to withstand extreme temperature and vibration conditions, reducing stress and oxidation effects, and maintaining a sealed connection under high-pressure and high-temperature conditions.
Smart Images
Figure 1.1
Abstract
Description
[0001] DESCRIPTION
[0002] TITLE: Swivel fitting for engine piping, associated piping and aircraft.
[0003] Technical field
[0004] The present invention relates to a swivel connection for piping of an engine, in particular of an aircraft engine.
[0005] Previous techniques
[0006] Swivel joints, or articulated joints, are intended to connect two fluid flow pipes together in a watertight manner, allowing relative movement between the two flow pipes, for example a bending movement.
[0007] Such connections are necessary for engine piping in order to reduce the space requirement in the engine area, the swivel connections having to withstand high temperature, vibration and pressure constraints, for example temperatures between 400 and 700°C, a vibration frequency of up to 2000 Hz, an acceleration of up to thirty times the acceleration of gravity at the surface of the earth, or 30g, and possibly reaching up to 100g in resonance conditions and pressures of between 5 and 30 bars for the engine of an aircraft.
[0008] A swivel joint comprises, for example, a female end piece having a substantially spherical end, a male end piece received in the female end piece and having a shoulder in the vicinity of its end, a ring threaded onto the male end piece, the outer face of which is substantially spherical, and a bellows interposed between the female end piece and the male end piece to urge the shoulder to bear against the ring so that the outer face of the ring is in sliding bearing against the inner face of the substantially spherical end of the female end piece.
[0009] Existing ball joints do not provide effective resistance to stresses in the engine area, particularly strong temperature variations and engine vibrations. In particular, such joints are flexible, but do not provide sufficient damping in the face of the engine's thermal and vibration regimes.
[0010] The bellows is an elastic thrust element that allows the ball joint to return to a position in which the two flow lines are aligned. The bellows is usually made of a flexible material that has no intrinsic damping properties.
[0011] The ring only serves a guiding function and does not improve the vibration resistance of the ball joint. The ring, located close to the flow lines, is sensitive to the temperature of the fluid circulating in the flow lines. This situation can lead to premature deterioration of the ring.
[0012] Statement of the invention
[0013] The present invention aims to overcome all or part of the aforementioned drawbacks.
[0014] The present invention relates to a swivel connection for engine piping, the connection being intended to connect together a first and a second fluid flow pipe and being provided with an annular casing comprising an internal element intended to be mounted on the first flow pipe and an external element intended to be mounted on the second flow pipe, an annular bearing arranged transversely between the internal element and the external element so as to be in contact with the internal element and the external element, the swivel connection comprising a metal bellows provided with a first end fixed to the internal element and a second end opposite the first end and fixed to the external element, the bellows comprising a stack of at least three metal layers.
[0015] Thus, the present invention allows a sealed connection between the two pipes, the at least three metal layers of the bellows having a particularly damping effect during engine vibrations. The friction between the at least three metal layers of the bellows generates damping, the increase in the number of metal layers of the bellows making it possible in particular to increase this damping.
[0016] Advantageously, the bellows comprises a stack of five metal layers.
[0017] Advantageously, the internal element extends longitudinally opposite the bellows.
[0018] Optionally, the bellows comprises at least three convolutions, the internal element extending longitudinally opposite at least two convolutions.
[0019] In one embodiment, the outer surface of the inner element intended to be in contact with the annular bearing is convex, the annular bearing comprising a concave inner surface slidingly bearing against said outer surface.
[0020] Advantageously, said outer surface comprises PTFE and / or graphite and / or a ceramic material.
[0021] Optionally, the external element comprises a shoulder, the annular bearing bearing against said shoulder.
[0022] In one embodiment, the annular bearing comprises a friable material.
[0023] Optionally, the annular bearing is located radially outside the bellows when the first and second flow lines are longitudinally aligned.
[0024] Advantageously, which friable material comprises graphite.
[0025] The invention also relates to a pipe comprising a first and a second fluid flow pipe, the pipe comprising a swivel connection as defined above, the internal element being mounted on the first flow pipe and the external element being mounted on the second flow pipe so as to join the first and second flow pipes.
[0026] The invention also relates to an aircraft comprising a swivel connection as defined above and / or piping as defined above. Brief description of the drawings
[0027] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which:
[0028] [Fig 1] schematically illustrates an aircraft comprising piping comprising a swivel connection according to the invention; and
[0029] [Fig 2] schematically illustrates a swivel connection according to the invention.
[0030] Detailed description
[0031] Figure 1 schematically represents an aircraft 2 comprising an engine 4. The engine 4 comprises a pipe 6 comprising a first flow line 8, a second flow line 10 and a swivel connection 12. The first and second flow lines 8, 10 are connected to each other in a sealed manner by the swivel connection 12. The swivel connection 12 allows relative movement between the first and second flow lines 8, 10, for example a bending movement, making it possible in particular to resist the conditions and vibrations in the engine zone 4, as well as allowing a smaller footprint in the engine zone 4 and therefore a reduced mass of the aircraft 2. The swivel connection 12 also makes it possible to reduce stresses induced by mounting clearances between the first and second flow lines 8, 10 or by thermal expansions of the components of the engine 4 occurring during operation of the engine 4.
[0032] Figure 2 schematically represents a detailed view of the swivel connection 12 connecting the first and second flow lines 8, 10, the first and second flow lines 8, 10 extending longitudinally along the longitudinal axis L. The swivel connection 12 comprises an annular casing 14, a metal bellows 16 and an annular bearing 18.
[0033] The metal bellows 16 is generally annular. The material composing the bellows comprises a stack of at least three metal layers 20, preferably five, the bellows 16 being represented here as comprising a stack of five metal layers 20.
[0034] The bellows 16 comprising at least three metal layers 20 obtains a damping function in particular by friction between adjacent metal layers 20. The number of metal layers
[0035] 20 also makes it possible to increase the lifespan of the bellows 16, for example a bellows 16 comprising five metal layers 20 will have a lifespan ten times greater than a bellows 16 comprising four metal layers 20, a bellows 16 comprising five metal layers 20 entering into resonance more difficultly than a bellows comprising four metal layers 20.
[0036] Preferably, the metal layers 20 of the bellows 16 are movable relative to each other. This characteristic makes it possible to generate a strong damping effect from the friction between the metal layers 20.
[0037] A metal layer 20 of the bellows 16 comprises, for example, a thin metal plate cut, rolled and welded longitudinally to form a ferrule. The different metal layers 20 of the bellows 16 are, for example, produced in the form of concentric ferrules so as to obtain a tube composed of several metal layers 20 which are closely spaced apart, i.e. spaced apart by a zero or negligible distance. A hydroforming process then makes it possible to create at least one convolution
[0038] 21 in said tube to form the bellows 16.
[0039] A first end 22 of the bellows 16 is mounted on the first flow line 8. For example, the first end
[0040] 22 is welded, stamped or machined to be tightly secured to one end 24 of the first flow pipe 8.
[0041] A second end 26 of the bellows 16, opposite the first end 22, is mounted on the second flow line 10. For example, the second end 26 is welded, stamped or machined to be tightly connected to an end 28 of the second flow line 10. The annular casing 14 comprises an internal element 30 comprising a mounting portion 32 welded, stamped or machined to be tightly connected to the first end 22 of the bellows 16.
[0042] The annular casing 14 also comprises an external element 34 comprising a mounting portion 36 welded, stamped or machined to be integral in a sealed manner with the second end 26 of the bellows 16.
[0043] Preferably, the bellows 16 comprises several convolutions 21, the bellows 16 shown comprising for example five convolutions 21. The internal element 30 comprises a shoulder 40 bearing against the convolution 21 of the bellows 16 closest to the first end 22 of the bellows 16. The external element 34 comprises a shoulder 42 bearing against the convolution 21 of the bellows 16 closest to the second end 26 of the bellows 16. This conformation allows the bellows 16 to exert a thrust force on the internal and external elements 30, 34 so as to take up compression forces tending to bring the first and second flow conduits 8, 10 closer or further apart.
[0044] The inner member 30 includes an elongated portion 44 extending the mounting portion 32 of the inner member 30 and extending longitudinally opposite the bellows 16. The annular bearing 18 is threaded around the inner member 30. An inner surface 46 of the annular bearing 18 is in contact with the elongated portion 44 of the inner member 30.
[0045] The outer element 34 comprises a curved portion 48 extending the mounting portion 36 of the outer element 34 so as to partially longitudinally surround the elongated portion 44. The annular bearing 18 comprises an outer surface 50, opposite the inner surface 46, in contact with the curved portion 48. In addition, the curved portion 48 forms a shoulder bearing on the complementary outer surface 50 of the annular bearing 18.
[0046] Advantageously, the outer surface of the internal element 30 intended to be in contact with the annular bearing 18 is convex, the inner surface 46 of the annular bearing 18 being concave. Thus, the annular bearing 18 is in sliding contact with the internal element 30, the relative movements between the first and second flow lines 8, 10 being facilitated. Advantageously, the outer surface of the internal element 30 intended to be in contact with the annular bearing 18 and the inner surface 46 of the annular bearing 18 are complementary and in particular produced in the form of sphere portions so as to allow a bending movement of the internal element 30 inside the external element 34, the bending movement corresponding for example to a rotation of the internal element 30 around the radial axis R.
[0047] Preferably, the outer surface of the elongated portion 44 intended to be in contact with the annular bearing 18 forms a shoulder guaranteeing the longitudinal and radial retention of the annular bearing 18 relative to the external element 34.
[0048] The elongated portion 44 comprises for example PTFE and / or graphite and / or a ceramic material, for example the outer surface of the elongated portion 44 intended to be in contact with the annular bearing 18 is covered with PTFE or graphite or the ceramic material so as to facilitate the relative movements between the first and second fluid flow lines 8, 10. Advantageously, the material on the outer surface of the elongated portion 44 also participates in a function of damping the relative movement between the first and second flow lines 8, 10.
[0049] Advantageously, the elongated portion 44 of the internal element 30 extends longitudinally opposite several convolutions 21. It is thus possible to use an annular bearing 18 having a large internal surface 46 so as to increase the contact surface between the annular bearing 18 and the internal element 30.
[0050] Preferably, the annular bearing 18 comprises a friable material, for example the annular bearing 18 is composed of or covered with the friable material. The friable material comprises, for example, graphite. The friable material releases particles of the friable material during friction of the annular bearing 18 with the elongated portion 44 so as to form a layer of solid lubricant 52. The friable material contributes to the damping character of the ball joint 12.
[0051] In one embodiment, the annular bearing 18 is formed from graphite and is obtained by sintering. Alternatively, the annular bearing 18 is formed by an equivalent powder metallurgy process.
[0052] Advantageously, the internal element 30 comprises a wedging portion 54 interposed between the mounting portion 32 of the internal element 30 and the elongated portion 44, so as to move the annular bearing 18 away from the fluid circulating in the first and second flow conduits 8, 10.
[0053] The separation of the annular bearing 18 from the first and second fluid flow lines 8, 10 makes it possible to reduce the effect of the temperature of the fluid on the annular bearing 18 and in particular to increase the resistance of the annular bearing 18 to oxidation, heat being a catalyst for oxidation reactions. The separation of the annular bearing 18 makes it possible to increase the service life of the annular bearing 18.
[0054] Preferably, the wedging portion 54 extends radially outwardly from the mounting portion 32 of the inner member 30 such that an end 56 of the wedging portion 54 is located radially outside the bellows 16 when the first and second flow lines 8, 10 are longitudinally aligned, the annular bearing 18 in contact with the outer surface of the inner member 30 being thus located radially outside the bellows 16. In other words, the minimum internal diameter of the annular bearing 18 is greater than the radial dimension of the bellows 16 measured when the first and second flow lines 8, 10 are not subject to flexing.
Claims
CLAIMS 1. Swivel connection (12) for piping (6) of an engine (4), the connection (12) being intended to connect together a first and a second flow pipe (8, 10) of a fluid and being provided with an annular casing (14) comprising an internal element (30) intended to be mounted on the first flow pipe (8) and an external element (34) intended to be mounted on the second flow pipe (10), an annular bearing (18) arranged transversely between the internal element (30) and the external element (34) so as to be in contact with the internal element (30) and the external element (34), characterized in that it comprises a metal bellows (16) provided with a first end (22) fixed to the internal element (30) and a second end (26) opposite the first end (22) and fixed to the external element (34), the bellows (16) comprising a stack of five metal layers (20).
2. A swivel joint (12) according to claim 1, wherein the internal element (30) extends longitudinally opposite the bellows (16).
3. Swivel joint (12) according to claim 2, wherein the bellows (16) comprises at least three convolutions (21), the internal element (30) extending longitudinally opposite at least two convolutions (21).
4. Swivel joint (12) according to any one of claims 1 to 3, wherein the outer surface of the inner element (30) intended to be in contact with the annular bearing (18) is convex, the annular bearing (18) comprising a concave inner surface (46) in sliding contact against said outer surface.
5. A swivel joint (12) according to claim 4, wherein said outer surface comprises PTFE and / or graphite and / or a ceramic material.
6. A swivel joint (12) according to any one of claims 1 to 5, wherein the external member (34) comprises a shoulder (48), the annular bearing (18) bearing against said shoulder (48).
7. A swivel joint (12) according to any one of claims 1 to 6, wherein the annular bearing (18) comprises a friable material, the friable material comprising in particular graphite.
8. A swivel joint (12) according to any one of claims 1 to 7, wherein the annular bearing (18) is located radially outside the bellows (16) when the first and second flow lines (8, 10) are longitudinally aligned.
9. Pipework (6) comprising first and second flow lines (8, 10) for a fluid, characterized in that it comprises a swivel connection (12) according to any one of claims 1 to 8, the internal element (30) being mounted on the first flow line (8) and the external element (34) being mounted on the second flow line (10) so as to join the first and second flow lines (8, 10).
10. Aircraft characterized in that it comprises a swivel connection (12) according to any one of claims 1 to 8 and / or piping (6) according to claim 9.