Together for a turbomachine
Flanges with oil guidance channels address the issue of uncontrolled oil projection in turbomachines, enhancing performance by minimizing torque loss and reducing oil fog.
Patent Information
- Application Number
- FR2022011094
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-10-25
- Publication Date
- 2025-01-31
- Estimated Expiration
- 2042-10-25
AI Technical Summary
Turbomachine components, particularly the bearings, experience high thermal stress and lubrication challenges due to uncontrolled projection of high-temperature oil, leading to reduced performance and increased oil fog.
Incorporation of flanges with oil guidance means, such as channels and openings, to redirect oil flow by gravity away from the central turbine components, reducing the amount of oil that falls on the bearings.
Enhances turbomachine performance by minimizing oil-related torque loss and reducing oil fog, thereby improving efficiency and reducing the overall mass of the turbomachine.
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Abstract
Description
Title of the invention: Assembly for a turbomachine Technical field of the invention
[0001] This document relates to an assembly for a turbomachine, such as an aircraft turbojet or turboprop. State of the prior art
[0002] A turbomachine of the prior art conventionally comprises, from upstream to downstream in the direction of circulation of the gases within the turbomachine, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine and a low-pressure turbine. The high-pressure turbine is connected to the low-pressure compressor via a high-pressure shaft. The low-pressure turbine is connected to the low-pressure compressor via a low-pressure shaft. The shafts are conventionally guided by bearings, for example by rolling bearings, in different areas of the shafts.
[0003] Current turbomachine shafts rotate at high speeds and are subjected to significant forces and torques, generating thermal stresses and increased lubrication requirements. During rotation of the shafts, high-temperature oil is projected into the enclosures containing the various bearings, in an uncontrolled manner and forming a significant oil mist.
[0004] Document EP 1 496 209 aims to limit such a phenomenon by equipping the bearing with upstream and downstream flanges, i.e. located axially on either side of the bearing, so as to contain such oil projections.
[0005] The terms axial, radial and circumferential are defined relative to the axis of rotation of the bearing, which conventionally corresponds to the axis of the turbomachine. Each flange comprises a first radial face facing said bearing and a second opposite radial face, each flange comprising openings regularly distributed around the circumference and radially along the flange. The openings extend axially from the first face to the second face and are intended to be crossed by the oil projected onto the flange.
[0006] Such flanges make it possible to recover the oil projected during operation of the turbomachine, this oil flowing along the faces of the flange by gravity before falling back and flowing towards a low point of the enclosure where the oil is evacuated. The travel time of the hot oil is thus reduced and the phenomenon of hot oil mist is limited.
[0007] However, some of the oil flowing over the faces of the flanges may fall back onto the shaft extending through the center of the bearing. This oil may take up some of the power or torque of the rotating shaft, affecting the performance of the turbomachine. Presentation of the invention
[0008] The present document aims to remedy this drawback, in a simple, reliable and inexpensive manner.
[0009] For this purpose, the present document relates to an assembly for a turbomachine, comprising an annular bearing extending around an axis, said bearing comprising a radially internal part and a radially external part capable of pivoting relative to each other around said axis, at least one flange extending radially opposite at least one part of the bearing, axially upstream and / or downstream of said bearing, said flange comprising a first face facing said bearing and a second opposite face, said flange comprising at least one opening extending axially from the first face to the second face, intended to be traversed by oil, characterized in that it comprises oil guiding means located at least in the upper part of the flange and in the radially internal part of said flange, capable of guiding the oil downwards by gravity.
[0010] The terms axial, radial and circumferential are defined relative to the axis of the bearing. The terms upstream and downstream are defined as being located axially on either side of the bearing. The terms up and down are defined relative to the general orientation of the Earth's gravity.
[0011] In this way, the guide means make it possible to guide the oil which is projected into the upper part of the flange and which flows downwards along the flange. Such guidance is ensured by gravity along the radially internal part of the flange, so as to limit the quantity of oil which can fall by gravity onto a central shaft, located radially inside the bearing.
[0012] This makes it possible to reduce the torque taken from said shaft and thus improve the performance of the turbomachine.
[0013] The oil guiding means may delimit at least one channel open upwards and extending circumferentially over at least part of the circumference, partly radially internal, of the first face and / or the second face of the flange.
[0014] The oil flowing along the corresponding face of the flange in the upper part of the flange thus falls back into the open channel and then flows circumferentially along said channel.
[0015] Said channel may also be open at its circumferential ends, so that oil may flow freely at said ends of the channel.
[0016] Said channel may extend circumferentially over an angular range of between 180 and 270°.
[0017] Said channel may extend symmetrically on either side of a vertical plane passing through said axis.
[0018] In this way, all of the oil collected and guided by said channel is diverted from a shaft extending inside the bearing.
[0019] Said channel may be formed by a wall extending axially and radially outwards from said radially inner periphery of the flange.
[0020] Said wall may be made of the same material as the rest of the flange or be formed by an independent element integral with the flange or one of the internal or external parts of the bearing.
[0021] Said channel may have an arcuate section or a rectangular section.
[0022] The flange may comprise a plurality of openings distributed around the circumference of the flange.
[0023] The puddles may comprise several series of openings, each series of openings comprising openings regularly distributed around the circumference, located on the same diameter, the diameters of the series being different from each other.
[0024] The openings of different series can be arranged in a staggered pattern around the circumference of the flange.
[0025] The porosity rate of the flange, that is to say the surface area of the openings divided by the total surface area of the first face of the flange, can be between 0.1 and 0.7.
[0026] The openings can be cylindrical. Of course, other shapes are also possible.
[0027] The oil guiding means may extend at the level of the first face of the flange, on the radially internal periphery of the flange.
[0028] The oil guiding means may extend at the level of the second face of the flange, radially inside said opening.
[0029] Thus the guide means can extend on one side only of the flange, or on both sides, that is to say upstream and downstream of the flange, that is to say axially from the first face and from the second face of the flange.
[0030] The bearing may be a rolling element bearing.
[0031] Said elements may be balls or rollers.
[0032] Said bearing may be a plain bearing.
[0033] The flange may be made of a single material with a nut or be formed by an element independent of and integral with said nut. Said nut is capable of bearing axially on the radially external part of the bearing.
[0034] The flange may be made of a material with an external annular ferrule or be formed by an element independent of and integral with said external ferrule. Said ferrule may comprise at least one annular part surrounding the radially external part of the landing.
[0035] A hoop may surround said outer ferrule and form an annular clearance between the radially outer periphery of the ferrule and the radially inner periphery of the hoop, this clearance being filled with oil in order to form an annular oil film constituting a damping system. Such an oil film is capable of damping vibrations of the bearing, essentially in the radial direction.
[0036] Said outer ferrule may be connected to a fixed support by means of elastic means. Said elastic means may comprise a plurality of pins elastically deformable in the radial direction, circumferentially spaced from each other and distributed over the circumference. Each pin may have a general U shape and comprise a radially internal part secured to the annular part of the ferrule surrounding the bearing and a radially external part secured to the fixed support, for example by means of a radial annular flange.
[0037] Such elastic means are known in particular from document FR 2 960 907.
[0038] The flange can be held axially in position between a nut and the bearing. In this case, the flange and the nut are formed from two separate elements or parts.
[0039] The flange may comprise a radial annular part, radially internal, comprising said opening, a radial annular part, radially external, interposed axially between the nut and the bearing, for example an external ring of the bearing.
[0040] The flange may comprise a cylindrical connecting part connecting the radially outer periphery of the radially inner part and the radially inner periphery of the radially outer part.
[0041] The present document also relates to a turbomachine comprising at least one assembly of the aforementioned type.
[0042] The turbomachine may be an aircraft turbojet or turboprop.
[0043] This document also relates to an aircraft comprising at least one turbomachine of the aforementioned type.
[0044] The aircraft may be an airplane or a rotary wing aircraft. Brief description of the figures
[0045] [Fig. 1] is a sectional view of a part of an assembly according to the present document,
[0046] [Fig.2] is a sectional and perspective view of part of a nut comprising a flaccid,
[0047] [Fig.3] is a perspective view of said nut
[0048] [Fig.4] is a sectional and perspective view of part of an external ferrule comprising a flange,
[0049] [Fig.5] is a sectional and detailed view illustrating the internal periphery of a flange according to an alternative embodiment,
[0050] [Fig.6] is a sectional and detailed view illustrating the internal periphery of a flange according to another embodiment,
[0051] [Fig.7] is a sectional and perspective view of an embodiment in in which the nut and the flange are formed from two separate elements. Detailed description of the invention
[0052] [Fig. 1] represents an assembly 1 according to the present document. This comprises an annular bearing 2 extending around an axis, said bearing 2 here being formed by a ball bearing comprising a radially inner ring 3, a radially outer ring 4, rolling elements, namely balls 5, mounted between said rings 3, 4 and held by a cage 6.
[0053] A shaft 7 of a rotor is mounted in the inner ring 3, directly or by means of intermediate elements 8 whose structure is not specified here.
[0054] The outer ring 4 is mounted inside a support 9, by means of a hoop 10 and an outer ferrule 11.
[0055] More particularly, the support 9 delimits a radially internal cylindrical bore 12 in which the annular ferrule 10 is mounted. A cylindrical part 13 of the external ferrule 11 is mounted inside the ferrule 10 and the external ring 4 of the bearing 2 is mounted inside the cylindrical part 13 of the external ferrule 11.
[0056] An annular clearance is formed between the radially outer periphery of the cylindrical portion 13 of the ferrule 11 and the radially inner periphery of the hoop 10, this clearance being filled with oil in order to form an annular oil film constituting a damping system. Such an oil film is capable of damping vibrations of the bearing 2, essentially in the radial direction.
[0057] Said external ferrule 11 is connected to the fixed support 9 by means of elastic means. Said elastic means comprise a plurality of pins 14 elastically deformable in the radial direction, circumferentially spaced from one another and distributed over the circumference. Each pin 14 has for example a general U shape and comprises a radially internal branch or part 15 secured to the cylindrical part 13 of the ferrule 11 and a radially external branch or part 16 secured to the fixed support 9, by means of a radial annular flange 17. The two parts 15, 16 are connected by a radial connection zone 18 and said flange 17 is fixed to the support 9, for example by means of bolts 19.
[0058] An annular flange 20 made of the same material as the outer ferrule 11 extends radially inwards from the inner branch 15.
[0059] The flange 20 is located downstream of the bearing 2, that is to say axially to the right of the bearing 2 in [Fig.l], and comprises a first face 21 facing said bearing 2 and a second opposite side 22.
[0060] The flange 20 further comprises axially oriented cylindrical openings 23 extending from the first face 21 to the second face 22, intended to be crossed by oil.
[0061] The openings 23 are regularly distributed around the circumference and in the radial direction, over the entire surface of the flange 20. In particular, the flange 20 may comprise several series of openings 23, each series of openings comprising openings 23 regularly distributed around the circumference, located on the same diameter, the diameters of the series being different from each other. The openings 23 of the different series may be arranged in a staggered pattern around the circumference of the flange 20.
[0062] The porosity rate of the flange 20, that is to say the surface area of the openings 23 divided by the total surface area of the first face 21 of the flange 20, may be between 0.1 and 0.7.
[0063] The radially inner periphery of the flange 20 comprises oil guiding means. These are formed by channels, grooves or channels 24, 25 open upwards and extending circumferentially over a part of the circumference, partly radially inner, of the first face 21 and of the second face 22 of the flange. The circumferential ends 26 ([Fig. 3]) of the channels 24, 25 are also open or emerging.
[0064] Thus, the guide means comprise a first channel 24 extending on the side of the first face 21 and a second channel 25 extending on the side of the second face 22.
[0065] Each channel 24, 25 can extend circumferentially over an angular range a of between 180 and 270° ([Fig.3]). Said channel 24, 25 extends symmetrically on either side of a vertical plane passing through said axis X.
[0066] Each channel 24, 25 here has a generally rectangular shape, delimited by a cylindrical wall 27 extending axially from the radially internal periphery of the corresponding face 21, 22 of the flange 20 and an annular radial wall 28 extending from the free end of said cylindrical wall 27.
[0067] The assembly 1 also comprises a nut 29 which comprises a body 30 capable of being screwed onto a threaded upstream part 31 of the cylindrical part 13 of the external ferrule 11 and capable of coming into axial support on the upstream end of the external ring 4 of the bearing 2.
[0068] A flange 20 extends radially inward from the body 30 of the nut 29, said flange 20 having a structure identical to the flange 20 of the external ferrule 11.
[0069] As illustrated in Figures 5 and 6, the channels 24, 25 may have a section of different shape, for example a section in the shape of an arc of a circle. In this case, the two channels 24, 25 upstream and downstream of the same flange 20 may be formed by a curved wall 32 upstream and a curved wall 32 downstream ([Fig.5]). Alternatively, the two channels 24, 25 may be formed by the same wall 33 comprising a curved portion 34 extending from the first face 21 or from the second face 22, so as to form one of the two channels 24, 25, then a portion 35 curved towards the opposite direction so as to form the other channel 24, 25.
[0070] In operation, oil is sprayed during rotation of the rotor 7 onto the first face 21 of each flange 20. A portion of the oil passes through the openings 23 to emerge on the second face 22. The oil then flows by gravity along the first and second faces 21, 22 of each flange 20.
[0071] In the upper part of the flanges 20, the oil is recovered by the channels 24, 25, then flows circumferentially along the channels 24, 25 until it reaches the circumferential ends 26 of the channels 24, 25. The oil contained in the channels 24, 25 then falls back by gravity, at a distance from the shaft 7, to then reach the oil evacuation zone.
[0072] This prevents oil from falling back onto the shaft 7, so as to maximize the performance of the turbomachine while limiting the phenomenon of oil mist and reducing the travel time of the oil within the enclosure.
[0073] It will be noted that, in this way, it is possible to limit the oil buffer volumes, and therefore also the mass of the turbomachine.
[0074] [Fig. 7] illustrates another embodiment, which differs from that described previously in that the nut 29 and the flange 20 are made of two separate parts. In particular, the flange 20 comprises a radial annular part 20a, radially internal, comprising the openings 23, a radial annular part 20b, radially external, interposed axially between the nut 29 and the ring 4 of the bearing 4, and a cylindrical connecting part 20c connecting the radially external periphery of the part 20a and the radially internal periphery of the part 20b.
Claims
Claims
1. Assembly (1) for a turbomachine, comprising an annular bearing (2) extending around an axis (X), said bearing (2) comprising a radially internal part (3) and a radially external part (4) capable of pivoting relative to each other around said axis (X), at least one flange (20) extending radially opposite at least one part of the bearing (2), axially upstream and / or downstream of said bearing (2), said flange (20) comprising a first face (21) facing said bearing (2) and a second opposite face (22), said flange (20) comprising at least one opening (23) extending axially from the first (21) face to the second face (22), intended to be traversed by oil, characterized in that it comprises oil guiding means (24, 25) located at least in upper part of the flange (20) and radially internal part of said flange (20), capable of guiding the oil downwards by gravity.
2. Assembly (1) according to claim 1, in which the oil guide means delimit at least one channel (24) open upwards and extending circumferentially over at least part of the circumference, partly radially internal, of the first face (21) and / or of the second face (22) of the flange (20).
3. Assembly (1) according to claim 2, wherein said channel (24) extends circumferentially over an angular range (a) between 180 and 270°.
4. An assembly (1) according to claim 2 or 3, wherein said channel (24) is formed by a wall (27, 28, 32) extending axially and radially outwards from said radially inner periphery of the flange (20).
5. Assembly (1) according to one of the preceding claims, in which said channel (24) has an arcuate section or a rectangular section.
6. Assembly (1) according to one of the preceding claims, in which the flange (20) comprises a plurality of openings (23) distributed around the circumference of the flange (20).
7. Assembly (1) according to one of the preceding claims, in which the oil guide means (24, 25) extend at the level of the first face (21) of the flange (20), at the radially internal periphery of the flange (20).
8. Assembly (1) according to one of the preceding claims, in which the oil guiding means (24, 25) extend at the level of the second face (22) of the flange (20), radially inside said opening (23).
9. Assembly (1) according to one of the preceding claims, in which the flange (20) is held axially in position between a nut (29) and the bearing (2).
10. Turbomachine comprising at least one assembly (1) according to one of the preceding claims.