Labyrinth seal rotary sealing device

Abstract

The invention relates to a rotary sealing device (20) comprising a first element (8) which rotatably mounted about a longitudinal axis (Ax) relative to a second element (12), wherein one of the first and second elements (8, 12) comprises a seal bearing surface (40) that has a first free end (42) and the other of the first and second elements (8, 12) comprises a seal (21) which forms a seal with a first face (41) of the seal bearing surface (40), the other of the first and second elements (8, 12) also comprising a portion (26) that comprises an outer face (27) opposite an inner face (28), the inner face (28) extending facing a second face (44) of the seal bearing surface (40) opposite the first face (41), such that a second free end (29) of the portion (26) has a non-zero offset (d29-42) with the first free end (42) in a direction parallel to the longitudinal axis (Ax). The invention also relates to a turbine engine comprising such a device (20).

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION

[0003] Rotating labyrinth seal device

[0004] TECHNICAL FIELD

[0005] The invention relates to the field of sealing devices for rotating elements and more particularly to sealing devices with labyrinth seals.

[0006] STATE OF THE PRIOR ART

[0007] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various carbon emission restrictions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new aircraft types and those already in operation, requiring the implementation of technological solutions to ensure their compliance with current regulations. Civil aviation has been mobilizing for several years now to contribute to the fight against climate change.

[0008] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

[0009] Consequently, the Applicant is constantly working to reduce its climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity. This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter onboard equipment, the development of the use of electric technologies to provide propulsion, and, as essential complements to technological progress, aeronautical biofuels.

[0010] To this end, the invention is the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft. For this purpose, the invention relates to reducing the consumption of lubricating oil and limiting the dispersion of this lubricating oil in the aircraft environment.

[0011] Conventionally, a bearing of a rotating element of a turbomachine is lubricated by centrifugal projection of lubricating oil. The bearings and their sprayed oil cloud are confined in an enclosure which must be sealed, as the lubricating oil can impair the operation of other parts of the turbomachine adjacent to the enclosure. A rotating sealing device generally comprises a lip seal or a labyrinth seal with licks secured to a fixed element and which comes to bear (lip seal) or is flush with a rotating shaft. To limit the quantity of oil that the seal must stop, it is known to install a drip-jet sealing device - or oil separator - near the seal. The drip-jet consists of a radial wall fixed in rotation to the rotating shaft and which centrifugally evacuates the oil particles projected onto the wall towards a collector.However, a quantity of oil passes through this type of dropper device and penetrates the labyrinth seal.

[0012] When the rotating element stops rotating, the oil droplets present in the labyrinth seal flow down the parts. In case of contact with the hot parts, these coke, which is detrimental to the operation of the turbomachine.

[0013] SUBJECT OF THE INVENTION

[0014] The object of the invention is to improve the sealing of a rotating sealing device of the seal type. DISCLOSURE OF THE INVENTION

[0015] For this purpose, a rotating sealing device is provided comprising a first element mounted to rotate about a longitudinal axis relative to a second element, in which one of the first and second elements comprises a seal surface having a first free end and the other of the first and second elements comprises a seal which provides a seal with a first face of the seal surface. The other of the first and second elements also comprises a portion having an outer face opposite an inner face. The inner face extends opposite a second face of the seal surface opposite the first, so that a second free end of the portion has a non-zero offset with the first free end in a direction parallel to the longitudinal axis.

[0016] This results in a sealing device equipped with a baffle which creates an air pressure zone and, by also reducing the air passage section, improves the effectiveness of the seal.

[0017] According to other particular, non-exclusive and optional embodiments of the invention: the outer face forms a first non-zero angle with the longitudinal axis, preferably, a first angle between twenty degrees and eighty degrees 0; the first free end comprises a first externally projecting protrusion, the apex of which forms a second acute angle with the longitudinal axis; the second free end comprises a second externally projecting protrusion which forms a third acute angle with the outer face; the outer face comprises a plurality of externally projecting teeth; the portion is connected to the other of the first and second elements by a continuous web which forms a fourth obtuse angle with the longitudinal axis; the seal is a labyrinth-type seal; the seal is integral with the first element.

[0018] The invention also relates to a turbomachine comprising a casing and a first rotating sealing device as described above, in which a rotor of the turbomachine is connected to the first element and the second element is connected to the casing, the casing receiving a bearing of the rotor. Optionally, the turbomachine comprises a second rotating sealing device located so that the first and second rotating sealing devices are located on either side of the bearing.

[0019] Other characteristics and advantages of the invention will appear on reading the following description of a particular non-limiting embodiment of the invention.

[0020] BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Reference will be made to the attached figures, including:

[0022] [Fig.l] Figure 1 is a schematic longitudinal sectional view of an aircraft engine;

[0023] [Fig.2] Figure 2 is a schematic longitudinal sectional view of a shaft provided with a sealing device according to a first embodiment of the invention;

[0024] [Fig.3] Figure 3 is a schematic longitudinal sectional view of a shaft provided with a sealing device according to a second embodiment of the invention.

[0025] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0026] In a turbomachine, here a shrouded turbojet engine marked 1 in figure 1, the air is admitted into an inlet sleeve 2 to pass through a fan comprising a series of rotating blades 3 before splitting into a central primary flow which circulates in a vein called a circulation vein of a primary air flow and a secondary flow surrounding the primary flow.

[0027] The primary flow is compressed by compressor stages 4 and 5 before reaching a combustion chamber 6, after which it expands by passing through turbines 7, before being evacuated, generating thrust. The secondary flow is propelled directly by the fan to generate the main thrust.

[0028] The compressor stages 4 and 5 comprise fixed distributors regularly spaced around a shaft 8 (not shown in fig. 1) mounted for rotation around a longitudinal axis AX in a nacelle 9 surrounding the assembly. The blades of the compressor stages 4 and 5 and of the turbines 7 are integral in rotation with the shaft 8. The shaft 8 is mounted for rotation relative to a static element, here to the nacelle 9 using several bearings 10 lubricated with oil and which are confined in enclosures 11.

[0029] In this text, the terms "inner" or "internal" and "outer" or "external" are used with reference to the position or orientation relative to the axis of rotation of the turbine of the turbojet engine 1. In this text, the terms "upstream" AM and "downstream" AV are used with reference to the position or orientation of an element according to the direction of air flow in the turbojet engine 1. An axial direction, a radial direction which is orthogonal to the axial direction and a circumferential direction which is orthogonal to the axial and radial directions are also defined.

[0030] With reference to Figure 2, the enclosure 11 comprises a casing 12 connected to the nacelle 9. The casing 12 comprises a downstream partition 13 crossed by the shaft 8 and which is provided with a rotating sealing device 20. The device 20 comprises a labyrinth seal 21 with licks 22 known per se and which is mounted tightly on the shaft 8 in order to be integral with it in rotation. The seal 21 has a downstream face 21.1 which abuts against a shoulder 8.1 of the shaft 8. The wipers 22 come opposite a seal surface 40 to create a sealed connection with a first face 41 of the surface 40. The seal surface 40 is integral with the casing 12 and extends substantially parallel to the axis Ax from the partition 13 upstream of the latter to end with a first free end 42. The free end 42 comprises a first protuberance 43 projecting radially externally from the seal surface 40 which connects the face 41 with a second face 44 of the surface 40 opposite the face 41.

[0031] The protuberance 43 has a vertex 43.1 which forms, here, an acute angle a43 with the longitudinal axis Ax. The device 20 also comprises a ring 23 keyed on the shaft 8 and which has a downstream face 23.1 which bears on an upstream face 21.2 of the seal 21. The ring 23 has an upstream face 23.2 on which a spacer 14 for separation with the bearing 10 bears.

[0032] The ring 23 comprises a body 24 substantially in the form of a right cylinder with a longitudinal axis Ax and projecting from which extends a continuous web 25 which forms an obtuse angle [325 with the longitudinal axis Ax. The web 25 connects the body 24 to a portion 26 substantially parallel to the axis Ax and which has an outer face T1 opposite an inner face 28. The inner face 28 extends opposite the face 44 of the seal surface 40. As can be seen in FIG. 2, the second free end 29 of the portion 26 has a non-zero offset distance d29-42 with the first free end 42 in a direction parallel to the longitudinal axis Ax.

[0033] In order to facilitate the flow of the oil deposited there when the rotation of the shaft 8 stops, the outer face Tl forms an angle 527, here equal to twenty degrees, with the longitudinal axis Ax.

[0034] This gives a sealing device provided with a baffle which creates an air pressurization zone and, by also reducing the air passage section, improves the effectiveness of the seal 21. The chosen inclinations of the outer face 27 and of the second face 44 as well as the protuberance 43 and its inclination limit the runoff of oil towards the seal 21 and therefore also contribute to improving the sealing of the device 20.

[0035] Elements identical or analogous to those previously described will bear a numerical reference identical to this in the following description of a second embodiment of the invention.

[0036] According to a second embodiment shown in Figure 3, the second free end 29 comprises a second protuberance 30 projecting externally from the portion 26 and which forms an acute angle Q30 with the external face 27. The external face T1 also comprises a plurality of teeth 31 projecting externally from the portion 26.

[0037] According to a third embodiment not shown, the turbomachine 1 comprises a second rotating sealing device installed so that the first sealing device 20 and the second rotating sealing device are located on either side of the bearing 10. The angle 527 constitutes a first angle 527, the angle a43 constitutes a second angle a43, the angle Q30 constitutes a third angle Q30, the angle 25 constitutes a fourth angle P25.

[0038] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0039] In particular, although here the seal is integral with the rotating element, the invention also applies to a sealing device in which the first element comprises the seal surface; although here the ring is keyed onto the shaft, the invention also applies to other types of rotational connection between the shaft and the first element of the rotating sealing device such as for example a connection by shrink fitting, gluing or screwing; although here the sealing device comprises a labyrinth seal, the invention also applies to other types of seal such as for example a lip-type rotating seal;although here the aircraft engine is ducted, the invention also applies to an unducted engine (also called "Open Fan") although here the outer face of the portion forms an angle of twenty degrees with the longitudinal axis, the invention also applies to other non-zero values ​​of first angle such as for example an angle greater than zero degrees and less than ninety degrees, preferably, an angle between twenty degrees and eighty degrees.;

Claims

CLAIMS 1. A rotating sealing device (20) comprising a first element (8) mounted to rotate about a longitudinal axis (Ax) relative to a second element (12), wherein one of the first and second elements (8, 12) comprises a seal surface (40) having a first free end (42) and the other of the first and second elements (8, 12) comprises a seal (21) which provides a seal with a first face (41) of the seal surface (40), the other of the first and second elements (8, 12) also comprising a portion (26) having an outer face (27) opposite an inner face (28), the inner face (28) extending directly opposite a second face (44) of the seal surface (40) opposite the first face (41), such that a second free end (29) of the portion (26) has a non-zero offset (d29-42) with the first end free (42) in a direction parallel to the longitudinal axis (Ax),and in which the outer face (27) forms a first non-zero angle (527) with the longitudinal axis (Ax), preferably a first angle (527) between twenty degrees and eighty degrees.

2. Rotating sealing device (20) according to claim 1, wherein the first free end (42) comprises a first protuberance (43) projecting externally and the apex (43.1) of which forms a second acute angle (a43) with the longitudinal axis (Ax).

3. A rotating sealing device (20) according to any preceding claim, wherein the second free end (29) comprises a second externally projecting protrusion (43) which forms a third acute angle (a43) with the outer face (27).

4. A rotating sealing device (20) according to any preceding claim, wherein the outer face (27) comprises a plurality of externally projecting teeth (31).

5. A rotating sealing device (20) according to any preceding claim, wherein the portion (26) is connected to the other of the first and second elements (8, 12) by a continuous veil (25) which forms a fourth obtuse angle (25) with the longitudinal axis (Ax).

6. A rotating sealing device (20) according to any one of the preceding claims, wherein the seal (21) is a labyrinth type seal.

7. A rotating sealing device (20) according to any one of the preceding claims, wherein the seal (21) is integral with the first element (8).

8. Turbomachine (1) comprising a casing (12) and a first rotating sealing device (20) according to any one of the preceding claims, in which a rotor (8) of the turbomachine (1) is connected to the first element (21) and the second element (40) is connected to the casing (12), the casing (12) receiving a bearing (10) of the rotor (8).

9. Turbomachine (1) according to claim 9, comprising a second rotating sealing device (20) according to any one of claims 1 to 5, in which the second rotating sealing device is located so that the first sealing device (20) and the second rotating sealing device are located on either side of the bearing (10).

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