TURBOMACHINE FOR AIRCRAFT

Abstract

The invention relates to a turbomachine (1) comprising: an annular stator (13), a shaft (10) arranged inside the annular stator (13), a lubrication chamber (18), an air chamber (19) axially separated from the lubrication chamber (18) by a sealing device (20), at least one bearing (14) for guiding the rotation of the shaft (10), a disc (23) arranged in the lubrication chamber (18), between the sealing device (20) and the bearing (14), the disc (23) being monobloc and integral with the shaft (10) and comprising an annular wall (24) extending into an annular cavity (25) formed in the annular stator (13), the cavity (25) being intended to receive a lubricating oil ring, characterized in that the cavity (25) is axially delimited by a first edge (25a) and a second edge (25b) extending radially into the turbomachine (1) from the annular stator (13), on either side of the annular wall (24).Abbreviation figure: 2.

Description

Title of the invention: TURBOMACHINE FOR AIRCRAFT Technical field of the invention

[0001] The invention relates to the technical field of aircraft turbomachines. Technical background

[0002] As is well known, an aircraft turbomachine extends around a longitudinal axis. It comprises a fan allowing the suction of an air flow dividing into a primary flow and a secondary flow. The primary flow passes through a primary vein of the turbomachine while the secondary flow is directed towards a secondary vein surrounding the primary vein. The secondary vein is delimited externally by a casing fixed to a nacelle of the aircraft and internally by a stator of the turbomachine.

[0003] The primary flow is compressed within, for example, a low-pressure compressor and then a high-pressure compressor of the turbomachine. The compressed air is then mixed with a fuel and burned within an annular combustion chamber arranged downstream of the series of compressors. The gases formed by the combustion pass through a high-pressure turbine and a low-pressure turbine located downstream of the combustion chamber and used to drive the compressors. The gases finally escape through a nozzle whose section allows the acceleration of these gases to generate propulsion.

[0004] The rotor of the low pressure turbine is connected to the fan and the rotor of the low pressure compressor by a low pressure shaft. The rotor of the high pressure turbine is connected to the rotor of the high pressure compressor by a high pressure shaft. The low pressure and high pressure shafts extend along the longitudinal axis.

[0005] The low pressure shaft is guided and centered in the stator of the turbomachine by at least one guide bearing. The guide bearing is interposed radially between one end of the low pressure shaft and a bearing support connected to the stator and which extends radially relative to the longitudinal axis.

[0006] In addition, the turbomachine generally comprises a lubrication device comprising a lubricating oil reservoir for distributing lubricating oil to the bearing. In order for the lubricating oil not to contaminate the related equipment of the turbomachine, the bearing is enclosed in a lubrication enclosure delimited by the low pressure shaft for example and the stator. Generally, the turbomachine also comprises an air enclosure adjacent to the lubrication enclosure. The pressure within the air enclosure, greater than in the lubrication enclosure, prevents oil leaks from the lubrication enclosure. In order to ensure the sealing of each enclosure, they are separated by a sealing device. The sealing device comprises, for example, a dynamic seal such as a labyrinth seal formed by wipers carried by the stator and cooperating with the low pressure shaft, for example.

[0007] However, under certain conditions, particularly under low speed conditions of the turbomachine, the lubricating oil may migrate and infiltrate into the sealing device. This reduces the performance of the sealing device which, in the long term, no longer fulfills its role. To minimize these risks of infiltration of the lubricating oil into the seal, the turbomachine may comprise a deflector arranged between the sealing device and the bearing. The deflector comprises an annular wall which prevents the lubricating oil from coming into contact with the sealing device. The annular wall also makes it possible to guide the lubricating oil towards an oil recovery device.

[0008] However, such a turbomachine is not entirely satisfactory. Indeed, the oil ring formed in the lubrication enclosure and centrifuged by the deflector is disturbed by the presence of clamping members, for example, connecting structures of the turbomachine. In addition, the bearing may be mounted on a damping oil film. Radial jets of oil from this oil film may also disturb the oil ring that forms in the enclosure. These disturbances of the oil ring tend to reduce the rotation speed of the oil ring driven by the deflector and consequently, the pressure delta. The performance of the deflector is therefore reduced. The quantity of oil recovered by the recovery device is therefore less and the risks of oil leakage through the sealing device are significant.

[0009] Therefore, there is a need to provide a turbomachine in which the risks of oil leakage from the lubrication enclosure are reduced. Summary of the invention

[0010] To this end, the invention proposes a turbomachine for an aircraft, extending around a longitudinal axis and comprising:

[0011] an annular stator extending around the longitudinal axis,

[0012] a shaft arranged inside the annular stator and extending along the longitudinal axis,

[0013] a lubrication enclosure delimited by the annular stator and the shaft,

[0014] an air enclosure axially separated from the lubrication enclosure by a device sealing,

[0015] at least one bearing for guiding the rotation of the shaft arranged in the lubrication enclosure and intended to be lubricated by a lubricating oil,

[0016] a disc arranged in the lubrication enclosure, between the sealing device and the bearing, the disc being in one piece and integral with the shaft and comprising an annular wall extending into an annular cavity formed in the annular stator, the cavity being intended to receive a ring of lubricating oil.

[0017] The invention is remarkable in that the cavity is delimited axially by a first edge and a second edge extending radially towards the inside of the turbomachine from the annular stator, on either side of the annular wall.

[0018] According to the invention, the cavity in which the annular wall of the disc extends and in which an oil ring is formed is delimited by a first and a second edge. The annular wall of the disc is thus, according to the invention, axially surrounded by the first and the second edge.

[0019] Such a configuration of the cavity allows the formation of a perfectly circular oil ring. Indeed, the cavity being delimited axially by the first and second edges, the oil ring is no longer disturbed by the presence of the clamping members for example which no longer extend into the cavity.

[0020] Also, the possible presence of a damping oil film of the bearing no longer disturbs the oil ring since the first and second edges make it possible to protect the oil ring from oil projections coming from the damping fluid film.

[0021] As a result, the rotational speed of the oil ring is improved. A higher rotational speed increases the centrifugal pressure delta and thus the final pressure delta. The larger the pressure delta, the more optimized the oil recovery and the reduced risk of leakage through the sealing device.

[0022] The invention may comprise one or more of the following features, taken in isolation from one another or in combination with one another:

[0023] - the cavity has a bottom connecting the first and second edges, the bottom being in fluid communication with a lubricating oil recovery circuit extending substantially tangentially relative to the bottom,

[0024] - the annular stator comprises a bearing support comprising a first sole, the bearing comprising a rolling body arranged between an outer ring cooperating with the first sole and an inner ring cooperating with the shaft, the outer ring and the first sole delimiting an annular space comprising an oil film,

[0025] - the disc comprises a cylindrical body extending along an axis parallel to the longitudinal axis, the sealing device being a dynamic seal arranged between the cylindrical body and a second sole of the bearing support,

[0026] - the first edge and the second edge are provided in the bearing support between the first and second sole,

[0027] - the first edge comprises a washer arranged in a groove formed in the bearing support, the washer being for example formed from a polymeric material chosen from elastomers or from a metallic material,

[0028] - the second edge is formed by a radial wall of the bearing support,

[0029] - the first and second edges are separated by a distance measured along the axis longitudinal between 20 mm and 50 mm, preferably less than 40 mm, and even more preferably less than 30 mm,

[0030] - the annular wall has an external end arranged in the cavity, having a height measured radially relative to the longitudinal axis between 1 mm and 10 mm.

[0031] The invention also relates to an aircraft comprising a turbomachine according to any one of the preceding characteristics, the turbomachine comprising a combustion chamber, the lubrication enclosure being arranged upstream or downstream of the combustion chamber. Brief description of the figures

[0032] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0033] [Fig-1] [Fig.l] is a schematic representation in axial section of a half aircraft turbomachine according to the invention,

[0034] [Fig.2] [Fig.2] is an enlarged view of a portion of [Fig.l],

[0035] [Fig.3a] [Fig.3a] is a schematic view of an element of [Fig.2],

[0036] [Fig.3b] [Fig.3b] is a cross-sectional view of an element of [Fig.2],

[0037] [Fig.4] [Fig.4] is a schematic representation in axial section of a part of the turbomachine according to an exemplary embodiment,

[0038] [Fig.5a] [Fig.5a] is a schematic representation in axial section of a part of a turbomachine according to another exemplary embodiment of the invention, in an assembly step,

[0039] [Fig.5b] [Fig.5b] is an enlarged view of [Fig.5a] and in another stage of assembly. Detailed description of the invention

[0040] An example of a turbomachine 1 for an aircraft is schematically represented in [Fig.l]. The turbomachine 1 extends along a longitudinal axis X.

[0041] The terms "upstream" and "downstream" are understood relative to the direction of flow F of the gases along the longitudinal axis X. The terms "axial" and "radial" and "internal" and "external" are understood relative to the longitudinal axis X.

[0042] The turbomachine 1 typically comprises, from upstream to downstream, a fan 2, at least one compressor such as a low-pressure compressor 3 and a high-pressure compressor 4, a combustion chamber 5, at least one turbine such as a high-pressure turbine 6 and a low-pressure turbine 7, and a nozzle 8.

[0043] The turbomachine 1 further comprises at least one shaft, for example a low pressure shaft 10 and a high pressure shaft 9.

[0044] In the particular example of [Fig.l], the rotor of the low pressure turbine 7 is connected to the fan 2 and to the rotor of the low pressure compressor by the low pressure shaft 10. The rotor of the high pressure turbine 6 is connected to the rotor of the high pressure compressor 4 by the high pressure shaft 9. The low pressure shaft 10 extends along the axis X.

[0045] The fan 2 allows the suction of an air flow dividing into a primary flow F1 and a secondary flow F2. The primary flow F1 passes through the engine of the turbomachine 1 while the secondary flow F2 is directed towards a secondary vein. The secondary vein is delimited externally by a casing 11 fixed to a nacelle of the aircraft (not shown) and internally by a first stator 12. The primary vein is delimited externally by an annular wall of the first stator 12 and internally by an annular stator 13. As visible in [Fig.l], the annular stator 13 extends around the longitudinal axis X and surrounds the low pressure shaft 10 which is arranged in the annular stator 13. The first stator 12 surrounds the annular stator 13.

[0046] The primary flow F1 is thus compressed within the low pressure compressor 3 then the high pressure compressor 4. The compressed air is then mixed with a fuel and burned within the combustion chamber 5. The gases formed by the combustion pass through the high pressure 6 and low pressure 7 turbines. The gases finally escape through the nozzle 8, the cross-section of which allows the acceleration of these gases to generate propulsion.

[0047] Furthermore, the low pressure shaft 10 is supported by at least one bearing 14 for guiding the rotation of the shaft, in particular the low pressure shaft 10. Advantageously, a plurality of bearings 14 support the low pressure shaft 10 and the high pressure shaft 9. The bearing 14 makes it possible to center and guide the rotation of the low pressure shaft 10 in the annular stator 13. In an exemplary embodiment shown in FIGS. 1 and 2, the bearing 14 is arranged on an upstream end 10a of the low pressure shaft 10. According to this example, the bearing 14 is arranged axially between the fan 2 and the combustion chamber 5. According to another exemplary embodiment shown in FIGS. 1 and 5b, the bearing 14 is arranged on a downstream portion 10b of the low pressure shaft 10. According to this example, the bearing 14 is arranged axially between the combustion chamber 5 and the nozzle 8. According to yet another embodiment shown in [Fig.l], a first bearing 14 is arranged on the upstream end 10a and a second bearing 14 is arranged on a downstream portion 10b of the low pressure shaft 10.

[0048] As best seen in [Fig.2] or [Fig.5b], the bearing 14 comprises a rolling body 140. The rolling body 140 is for example a roller or a ball. The rolling body 140 is interposed radially between an outer ring 141 and an inner ring 142. The outer and inner rings 141, 142 are generally metallic.

[0049] The outer ring 141 has an outer surface and an opposite inner surface facing the rolling body 140. The outer ring 141 comprises a central portion and two longitudinal ends arranged on either side of the central portion. The outer surface comprises two annular grooves 141a. The annular grooves 141a are for example formed on the longitudinal ends of the outer surface of the outer ring 141. The rolling body 140 is for example centered on the outer ring 141. A seal 141b is arranged in each of the annular grooves 141a.

[0050] Advantageously, the annular stator 13 comprises a bearing support 15 making it possible to connect the bearing 14 to a fixed structure of the turbomachine 1. The bearing support 15 extends radially towards the inside of the turbomachine 1. As shown in [Fig. 2], the bearing support 15 comprises for example a first branch 150 and a second branch 151. The first branch 150 comprises a first end flange 150a and the second branch 151 comprises a second end flange 151a cooperating with the first end flange 150a to connect the first and second branches 150, 151 together. The first branch 150 comprises a first sole 150b and the second branch 151 comprises a second sole 151b. The first sole 150b cooperates with the outer ring 141. The first sole 150b extends for example around the outer ring 141. The first sole 150b is for example fixed to the outer ring 141 by a fixing member 16 such as a bolt.

[0051] The outer ring 141 and the first sole 150b delimit an annular space 17. The annular space 17 is delimited radially by the outer ring 141 and the first sole 150b. The annular space 17 comprises an oil film confined between the seals 141b. The oil is under pressure. The oil film is commonly called a “squeeze film” in the field of the invention. The oil film makes it possible to dampen and therefore limit the effects of the forces transmitted by the outer ring 141b to the annular stator 13 via the bearing support 15.

[0052] The bearing 14 is intended to be lubricated during operation of the turbomachine 1. For this purpose, passages 100 for lubricating oil are provided in the low pressure shaft 10 and in the internal ring 142.

[0053] As better visible in [Fig.2], in order to limit contamination of the equipment of the turbomachine 1 by the lubricating oil, the bearing 14 is placedin a lubrication enclosure 18. According to an exemplary embodiment, the lubrication enclosure 18 is arranged upstream of the combustion chamber 5. The enclosure is then an upstream enclosure having an upstream end of the lubrication enclosure 18 as shown in more detail in [Fig.2]. According to another example, the lubrication enclosure 18 is arranged downstream of the combustion chamber 5 and is therefore a downstream enclosure having a downstream end of the lubrication enclosure 18 as shown in more detail in [Fig.5b]. The lubrication enclosure 18 is delimited radially by the annular stator 13 and the low pressure shaft 10. The lubrication enclosure 18 is separated axially from an air enclosure 19 by a sealing device 20. The pressure in the air enclosure 19 is greater than or equal to the pressure in the lubrication enclosure 18.The air enclosure 19 thus makes it possible to maintain an external pressure greater than or equal to the pressure in the lubrication enclosure 18 in order to limit leaks of lubricating oil through the sealing device 20.

[0054] The sealing device 20 is for example a dynamic seal. The dynamic seal is arranged between a cylindrical body 22 and the second sole 151b.

[0055] According to a first example not shown, the sealing device 20 comprises at least one labyrinth seal cooperating with an abradable surface. The labyrinth seal comprises a series of teeth arranged in the second sole 151b and extending around the cylindrical body 22 movable in rotation around the longitudinal axis X carrying the abradable surface. The teeth form cavities around the cylindrical body 22 which make it possible to limit the passage of oil from the lubrication enclosure 18 to the air enclosure 19.

[0056] According to another example shown in [Fig. 2], the sealing device 20 comprises for example a brush seal 21. The brush seal 21 comprises a brush 21a carried by the second sole 151b and extending around the cylindrical body 22. In order to protect the brush seal 21 from oil splashes, an oil recovery surface 21b is provided in the second sole 151b downstream of the brush seal 21. The recovery surface 21b is provided with teeth which form cavities around the cylindrical body 22 to limit the passage of oil towards the brush 21a.

[0057] According to another example shown in [Fig.5b], the sealing device 20 comprises for example a segmented radial seal 211. The segmented radial seal 211 comprises a plurality of carbon segments carried by the second sole 151b and extending around the cylindrical body 22.

[0058] The lubrication enclosure 18 further comprises an annular cavity 25 intended to receive a ring of lubricating oil. The cavity 25 is annular. The cavity 25 is formed in the annular stator 13. More particularly, the cavity 25 is formed in the bearing support 15. The cavity 25 is offset axially and / or radially by relative to the bearing 14. The cavity 25 is axially delimited by a first edge 25a and a second edge 25b. The first and second edges 25a, 25b extend radially inwards from the annular stator 13, in particular from the bearing support 15. The first and second edges 25a, 25b are thus formed in the bearing support 15, for example between the first sole 150b and the second sole 151b. The first and second edges 25a, 25b are for example formed in the second branch 151 of the bearing support 15.

[0059] Advantageously and as better visible in Figures 4 or 5b representing a downstream enclosure 18, the first edge 25a comprises a washer 26 arranged in a groove formed in the bearing support 15, and in particular in the second branch 151. The washer 26 forms the first edge 25a and makes it possible to adjust the width of the cavity 25 without modifying the architecture of the bearing support 15. The washer 26 may be metallic or polymeric. The polymeric material is for example chosen from elastomers. According to a first example shown in [Fig.4], the washer 26 is formed of a metallic material. According to another example shown for example in [Fig.5b], the washer 26 is for example formed of a polymeric material chosen for example from elastomers. An elastomeric washer 26 makes it easier to mount the turbomachine 1 since it is more deformable than the metallic washer 26.

[0060] Advantageously, the second edge 25b is formed by a radial wall of the bearing support 15. The second edge 25b is therefore metallic.

[0061] The description of the first and second edges 25a, 25b also applies when the lubrication enclosure 18 is the upstream enclosure.

[0062] Advantageously, and with reference to [Fig. 3a], the first and second edges 25a, 25b are separated by a distance D measured along the longitudinal axis X of between 20 mm and 50 m, preferably less than 40 mm and even more preferably less than 30 mm. The distance D defines the width of the cavity 25.

[0063] The cavity 25 has for example a bottom 25c connecting the first and second edges 25a, 25b. The first and second edges 25a, 25b extend radially from the bottom 25c and towards the longitudinal axis X of the turbomachine 1. The first and second edges 25a, 25b respectively form a first angle α and a second angle β with the bottom 25c of 90°. According to another example not shown, the first and second angles α, β are less than 120°, for example between 45° and 90° and advantageously the first and second angles α, β are 60°. The first and second angles α, β may be identical or different. The bottom 25c is formed in the bearing support 15. The bottom 25c is in fluid communication with an oil recovery circuit 27 shown schematically in [Fig.3a] and 3b. Preferably, the oil recovery circuit 27 extends substantially tangentially relative to the bottom 25c. Thus, the lubricating oil is discharged tangentially relative to the bottom 25c and, relative to the oil ring formed in the cavity 25. The bottom 25c comprises for example an orifice 25d for discharging the oil. The recovery circuit 27 comprises a pipe. The width of the cavity 25 and therefore of the bottom 25c as described above is sufficiently wide to ensure the connection with the recovery circuit 27.

[0064] In order to improve the sealing of the lubrication enclosure 18, the turbomachine 1 further comprises a disc 23 arranged in the lubrication enclosure 19 between the sealing device 20 and the bearing 14. The disc 23 ensures the centrifugation of the lubricating oil and forms a rotating oil ring in the cavity 25.

[0065] The disc 23 is integral with the low pressure shaft 10. The disc 23 is thus movable in rotation about the longitudinal axis X. The disc 23 is arranged axially between the sealing device 20 and the bearing 14. The disc 23 according to the invention is in one piece. It is also rigid. By rigid, it is understood that the disc 23 only deforms substantially under the effect of mounting forces for example. The disc 23 is metallic. It comprises an annular wall 24 extending into the cavity 25, between the first and second edges 25a, 25b. The annular wall 24 has a roughness greater than 200 μm, and advantageously greater than 500 μm.

[0066] The disc 23 makes it possible to divert the flow of oil particles to direct it away from the sealing device 20. Also, the disc 23, and in particular the annular wall 24, makes it possible to generate a centrifugal pressure delta which allows the recovery of the oil within the recovery circuit 27. The pressure delta depends on the rotation speed of the oil ring in the cavity 25. The latter being perfectly cylindrical thanks to the edges 25a, 25b, and free from oil projections from the oil film, the rotation speed of the oil ring in the cavity 25 is improved. This thus makes it possible to increase the centrifugal pressure delta and therefore to improve the recovery of oil within the recovery circuit 27.

[0067] Furthermore, the pressure delta is even greater according to the invention since the tangential recovery of the lubricating oil advantageously makes it possible to generate, in addition to the centrifugal pressure delta generated by the rotational drive of the oil ring by the disc 23, a dynamic pressure delta. Thus, for a given rotation speed, the pressure delta is increased even more since it is the sum of the centrifugal pressure delta and the dynamic pressure delta. This makes it possible to make the recovery of oil in the pipe 27 more efficient and to minimize the risks of leakage.

[0068] Advantageously, and as best seen in [Fig.3a], the annular wall 24 has an annular external end 24a having a height H measured radially relative to the longitudinal axis X of between 1 mm and 10 mm arranged in the cavity 25. The height H is preferably between 2 mm and 7 mm. Such a height H of the annular wall 24 arranged in the cavity 25 makes it possible to ensure a sufficient soaking height of the disc 23.

[0069] Preferably, the height Y between the bottom 25c of the cavity 25 and the external end 24a of the annular wall 24 is between 1 mm and 10 mm, preferably between 2 mm and 5 mm.

[0070] The disc 23 further advantageously comprises the cylindrical body 22 which is connected to the annular wall 24 by a frustoconical region 28 for example. The frustoconical region 28 is arranged around the low pressure shaft 10 and is fixed to the latter. The cylindrical body 22 has a longitudinal axis parallel to the longitudinal axis X of the turbomachine 1.

[0071] A manufacturing method will now be described. In a first step illustrated in [Fig.5a], the bearing 14 and the disc 23 are mounted on the low pressure shaft 10. The bearing support 15 is also arranged around the low pressure shaft 15, the first sole 150b being axially offset relative to the outer ring 141.

[0072] Then, the low pressure shaft 10 is moved in translation from upstream to downstream as indicated by the arrow.

[0073] As illustrated in [Fig.5b], the bearing 14 and the disc 23 are then put into position, the disc 23 then extending into the cavity 25. This assembly is facilitated by the washer 26 made of elastomeric material. Indeed, the washer 26 is in this example sufficiently deformable to allow the passage of the disc 23.

[0074] Thanks to the invention, the cavity 25 is perfectly circular and is not contaminated by shape accidents such as the clamping members for example or oil projections from the oil film. The recovery of the oil within the recovery circuit 27 is thus improved, which makes it possible to limit the risks of oil leakage through the sealing device 20.

Claims

Claims

1. Turbomachine (1) for an aircraft, extending around a longitudinal axis (X) and comprising: an annular stator (13) extending around the longitudinal axis (X), a shaft (10) arranged inside the annular stator (13) and extending along the longitudinal axis (X), a lubrication enclosure (18) delimited by the annular stator (13) and the shaft (13), an air enclosure (19) axially separated from the lubrication enclosure (18) by a sealing device (20), at least one bearing (14) for guiding the rotation of the shaft (10) arranged in the lubrication enclosure (18) and intended to be lubricated by a lubricating oil, a disc (23) arranged in the lubrication enclosure (18), between the sealing device (20) and the bearing (14), the disc (23) being in one piece and integral with the shaft (10) and comprising an annular wall (24) extending into an annular cavity (25) formed in the annular stator (13),the cavity (25) being intended to receive a ring of lubricating oil, characterized in that the cavity (25) is delimited axially by a first edge (25a) and a second edge (25b) extending radially towards the inside of the turbomachine (1) from the annular stator (13), on either side of the annular wall (24), the cavity (25) further having a bottom (25c) connecting the first and second edges (25a, 25b), the bottom (25c) being in fluid communication with a recovery circuit (27) of the lubricating oil extending substantially tangentially relative to the bottom (25c).,

2. Turbomachine (1) according to the preceding claim, characterized in that the annular stator (13) comprises a bearing support (15) comprising a first sole (150b), the bearing (14) comprising a rolling body (140) arranged between an outer ring (141) cooperating with the first sole (150b) and an inner ring (142) cooperating with the shaft (10), the outer ring (141) and the first sole (150b) delimiting an annular space (17) comprising a film of oil.

3. Turbomachine (1) according to the preceding claim, characterized in that the disc (23) comprises a cylindrical body (22) extending along an axis parallel to the longitudinal axis (X), the sealing device (20) being a dynamic seal arranged between the cylindrical body (22) and a second sole (151b) of the bearing support (15).

4. Turbomachine (1) according to the preceding claim, characterized in that the first edge (25a) and the second edge (25b) are provided in the bearing support (15) between the first (150b) and the second sole (151b).

5. Turbomachine (1) according to the preceding claim, characterized in that the first edge (25a) comprises a washer (26) arranged in a groove formed in the bearing support (15), the washer (26) being for example formed from a polymeric material chosen from elastomers or from a metallic material.

6. Turbomachine (1) according to any one of claims 2 to 5, characterized in that the second edge (25b) is formed by a radial wall of the bearing support (15).

7. Turbomachine (1) according to any one of the preceding claims, characterized in that the first and second edges (25a, 25b) are separated by a distance (D) measured along the longitudinal axis (X) of between 20 mm and 50 mm, preferably less than 40 mm, and even more preferably less than 30 mm.

8. Turbomachine (1) according to any one of the preceding claims, characterized in that the annular wall (24) has an external end arranged in the cavity (25), having a height (H) measured radially relative to the longitudinal axis (X) of between 1 mm and 10 mm.

9. Aircraft comprising a turbomachine (1) according to any one of the preceding claims, the turbomachine (1) comprising a combustion chamber (5), the lubrication enclosure (18) being arranged upstream or downstream of the combustion chamber (5).

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