MODULE FOR AN AIRCRAFT TURBOMACHINE
An oil deflector redirects oil from decoupled bearing supports in an aircraft turbomachine to prevent contamination, maintaining clean air supply by guiding it to a safer location within the engine.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- SAFRAN AIRCRAFT ENGINES SAS
- Filing Date
- 2024-05-24
- Publication Date
- 2026-06-05
AI Technical Summary
The risk of oil leakage into the primary channel due to the decoupling of bearing supports in an aircraft turbomachine, leading to contamination of the engine and potential supply of polluted air to the aircraft, is not adequately addressed by existing shear screw decoupling devices.
An oil deflector is positioned between the bearing flanges to collect and guide oil flowing from the lubrication chamber, redirecting it to a less critical location within the engine, such as the rotor drum, upon shear screw failure.
Prevents oil contamination of the primary airflow by effectively guiding oil away from critical engine components, ensuring clean air supply to the aircraft.
Smart Images
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Abstract
Description
Title of the invention: MODULE FOR AN AIRCRAFT TURBOMACHINE Technical field of the invention
[0001] The present invention relates to a module for an aircraft turbomachine, as well as a turbomachine comprising such a module. Technical background
[0002] The prior art includes in particular document EP-B1-2 721 260.
[0003] An aircraft turbomachine includes a gas generator which conventionally comprises, from upstream to downstream, with reference to the flow of gases in the turbomachine, at least one compressor, an annular combustion chamber and at least one turbine.
[0004] In the case of a twin-spool turbofan engine, with low-pressure and high-pressure components respectively, the gas generator comprises successively a low-pressure compressor, a high-pressure compressor, the combustion chamber, a high-pressure turbine, and a low-pressure turbine. The gas generator defines a first annular flow path of gas, called the primary flow, which passes through the compressors, the combustion chamber, and the turbines.
[0005] The rotor of the high-pressure compressor is connected to the rotor of the high-pressure turbine by a high-pressure shaft. The rotor of the low-pressure compressor is connected to the rotor of the low-pressure turbine by a low-pressure shaft which passes through the high-pressure shaft and drives a shaft of a propulsion propeller generally located upstream of the gas generator.
[0006] When this propeller is enclosed and therefore surrounded by an annular casing, this propeller is called a blower and generates an airflow, called a secondary flow, which flows around the gas generator.
[0007] The propeller shaft and the low-pressure shaft are guided by bearings housed in a lubrication enclosure. This enclosure is surrounded by the first channel and is at least partially delimited by bearing supports. A first rolling bearing located upstream is supported by a first bearing support, and a second rolling bearing located downstream is supported by a second bearing support. These bearing supports have annular flanges that are radially oriented and axially applied to each other and to an annular flange of a stator housing.
[0008] The lubrication chamber is designed to lubricate the bearings and maintain an oily atmosphere around them. The oil is supplied to the chamber via a supply circuit.
[0009] The propeller includes blades that are susceptible to breakage, although this phenomenon is extremely rare. In such a case, a significant imbalance appears on the propeller shaft, generating cyclic loads and vibrations that the upstream bearing transmits to the stator, with a considerable risk of damage.
[0010] To limit the forces transmitted to the stator in the presence of a large imbalance, a shear screw decoupling device is known from document FR-A1-2 831 624. In practice, the second bearing support is fixed to the stator housing by non-shear screws, and the first bearing support is fixed to the second bearing support by shear screws to form a connection that can be broken. These so-called "fuse" screws, whose operation is fully described in the aforementioned document, have a reduced cross-section portion that is likely to break beyond a predetermined mechanical tensile force and thus achieve the decoupling of the bearing supports. In this situation of shear screw failure, the first bearing support is no longer axially restrained. It moves axially upstream and therefore moves axially away from the second bearing support. This is especially true when the bearing supported by the first bearing support is a roller bearing, which does not provide axial restraint to the first bearing support when it is separated from the second bearing support.
[0011] This phenomenon is problematic because the housing continues to be supplied with oil by the aforementioned circuit, and the oil that accumulates in the housing is likely to pass through the annular passage formed between the bearing support flanges, which have moved axially apart. The oil then spills into the engine, generating contamination. This oil can reach the first air intake from which air is drawn to supply air to the aircraft equipped with the turbomachine. There is therefore a risk that the aircraft will be supplied with polluted air, or even with unpleasant fumes and odors.
[0012] The invention relates to a technical solution aimed at eliminating the risk of oil leakage into the primary channel after decoupling the bearing supports from the lubrication chamber. Summary of the invention
[0013] The invention relates to a module for an aircraft turbomachine, this module comprising:
[0014] - a first annular bearing support which extends around an axis and which comprises a first annular fixing flange,
[0015] - a second annular bearing support which extends around the axis and which comprises a second annular fixing flange, the first and second flanges being suitable for to be applied axially against each other and to be fixed together by shear screws,
[0016] - an annular housing that extends around the axis, the second bearing support being fixed to the crankcase,
[0017] - a lubrication chamber which is at least partly delimited by the first bearing support, this lubrication enclosure containing a first bearing supported by the first bearing support and a second bearing supported by the second bearing support, and
[0018] - an oil supply circuit for the enclosure,
[0019] - an annular flow vein of a gas stream, this vein extending around the shaft and lubrication chamber, and
[0020] - an oil deflector which is radially interposed between the vein and the enclosure, and which is located approximately at the right of the first and second flanges, the deflector being configured to receive and guide the oil likely to flow by gravity from an annular passage between the first and second flanges which would result from a breakage of the fusible screws and an axial separation of the flanges.
[0021] Under normal operating conditions, shear screws ensure the axial retention of the first bearing support relative to the second bearing support. If the shear screws break, the bearing supports separate and move axially apart. The axial displacement of the first bearing support, away from the second bearing support, results in the formation of an annular passage between the flanges of the bearing supports. The oil contained in the housing is likely to pass through this passage and flow by gravity into the engine until it reaches the aforementioned first oil channel. To prevent such contamination and control the oil flow in this situation, an oil deflector is provided. This deflector is cleverly positioned to collect the oil flowing by gravity as described above and to guide it to a less critical location than the engine oil channel.
[0022] The module according to the invention may comprise one or more of the following features, taken individually or in combination with each other: • the deflector has a general curved shape around the axis and has a predetermined angular extent around the axis; • the deflector has an angular range between 30 and 100°; • The deflector is located in the lower part of the module and is traversed in its middle by a plane passing through the axis and at 6 o'clock by analogy with the face of a clock; • the deflector includes a portion of a frustoconical wall; • the deflector comprises two radially external circumferential rims, between which extends the portion of frustoconical wall; • the deflector includes at least one notch for the passage of a conduit of the module, such as an oil conduit of said circuit; • the deflector extends in a circumferential direction between two conduits of the module, such as oil lines; • the vein is at least partly delimited, radially inside, by a rotor drum which carries stages of rotor blades, the deflector being at least partly interposed radially between the enclosure and the drum and being configured to discharge the oil received radially inside this drum; • the portion of the truncated conical wall is flared on the side of the drum and one of said edges is surrounded by the drum; • the vein is furthermore at least partly delimited, radially inside, by an annular wall of said casing, the deflector being at least partly interposed radially between the enclosure and this wall; • the other of said edges is surrounded by said casing wall; • the flange of the second bearing support is axially interposed between the flange of the first bearing support and another flange of the housing; • the flange of the second bearing support is fixed to the flange of the casing by non-shear screws;
[0023] — the deflector is formed from a single piece.
[0024] The present invention also relates to an aircraft turbomachine, comprising at least one module as described above. Brief description of the figures
[0025] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:
[0026] [Fig-1] [Fig.1] is a schematic half-view in axial section of a part of a aircraft turbomachine,
[0027] [Fig.2] [Fig.2] is a partial schematic axial cross-sectional view of an enclosure bearing lubrication,
[0028] [Fig.3] [Fig.3] is a larger-scale view of part of [Fig.2] and shows a decoupling device comprising fusible screws, here unbroken,
[0029] [Fig.4] [Fig.4] is a view similar to that of [Fig.3] and shows the device decoupling with fusible screws, which are broken here.
[0030] [Fig. 5] [Fig. 5] is a schematic axial cross-sectional view of a module according to the invention and in particular an oil deflector of this module;
[0031] [Fig.6] [Fig.6] is a partial schematic perspective view of the module and the oil deflector of the [Fig.5];
[0032] [Fig.7] [Fig.7] is another partial schematic view in section and perspective of the module and the oil deflector of [Fig.5];
[0033] [Fig.8] [Fig.8] is a larger-scale view of part of [Fig.7]; and
[0034] [Fig.9] [Fig.9] is a larger scale view of another part of [Fig.8]. Detailed description of the invention
[0035] Fig. 1 shows a turbomachine 10 for an aircraft, this turbomachine 10 being here a twin-spool turbojet.
[0036] Axis A designates the longitudinal axis of the turbomachine.
[0037] The turbomachine 10 comprises a gas generator 12 which includes, from upstream to downstream with reference to the gas flow along axis A, a low-pressure (LP) compressor 14, a high-pressure (HP) compressor, an annular combustion chamber, a high-pressure (HP) turbine, and a low-pressure (LP) turbine. The turbomachine 10 is partially shown, and only the LP compressor 14 is depicted in the drawing.
[0038] Although not visible in [Fig.1], the HP compressor rotor is connected to the HP turbine rotor by a high-pressure shaft, and the LP compressor rotor 14 is connected to the LP turbine rotor by a low-pressure shaft which passes through the high-pressure shaft and drives a propulsion propeller, called a blower 16, located upstream of the gas generator 12 and which is surrounded by an annular casing called a blower casing 18.
[0039] The blower housing 18 is connected to the gas generator 12 by an intermediate housing 20 which includes a central hub 22 and a series of radial arms 24 connecting the hub 22 to the blower housing 18.
[0040] The gas generator 12 defines a main annular flow channel V1 of a first air flow, called primary flow FL. The gas generator 12 is surrounded by a secondary annular flow channel V2 of a second air flow, called secondary flow F2.
[0041] The airflow F entering the blower 16 splits into a portion forming the primary flow FL. The air in this primary flow FL is compressed in the BP 14 and HP compressors, then mixed with fuel and burned in the combustion chamber. The combustion gases of the primary flow are then expanded in the HP and BP turbines and finally flow through an exhaust nozzle.
[0042] The other part of the airflow entering the blower 16 forms the secondary flow F2 and is intended to be mixed with the primary flow Fl downstream of the nozzle.
[0043] Figure 1 further shows a module 30 of the turbomachine, this module 30 comprising annular bearing supports 32, 34, an annular housing 36, a lubrication chamber 38 and an oil supply circuit 40 for the chamber 38.
[0044] A first annular bearing support 32 extends around the axis A and includes a first annular fixing flange 32a, more clearly visible in [Fig.2].
[0045] A second annular bearing support 34 extends around the axis A and includes a second annular mounting flange 34a. The flanges 32a, 34a extend radially outwards and are suitable for being applied axially against each other and fixed together by screws 42 which are shear-off and more clearly visible in figures 2 to 4.
[0046] An annular housing 36 extends around axis A, and the second bearing support 34 is fixed to this housing 36 by screws that are not shear-resistant and are not shown in the drawings. The shear-resistant and non-shear-resistant screws 42 may be located on the same circumference centered on axis A. The housing 36 may be the intermediate housing 20 of [Fig. 1] or another housing fixed to or integral with this intermediate housing 20.
[0047] The housing 36 includes a flange 36a onto which the flange 34a is applied and fixed by the aforementioned non-sheathable screws. The flange 34a of the second bearing support 34 is axially interposed between the flange 32a of the first bearing support 32 and the flange 36a of the housing 36, as illustrated in Figures 2 to 4.
[0048] The lubrication enclosure 38 is at least partly delimited by the first bearing support 32 and contains a first bearing 44, or upstream bearing, carried by the first bearing support 32, and a second bearing 46, or downstream bearing, carried by the second bearing support 34.
[0049] In the example shown, the upstream bearing 44 is a roller bearing and the downstream bearing 46 is a ball bearing.
[0050] Furthermore, in the example shown, the first bearing support 32 has a generally annular and elongated shape along the axis A, and comprises an upstream end carrying the rolling bearing 44, and a downstream end connected to the flange 32a. The second bearing support 34 has a generally annular and radial shape, and comprises a radially internal end carrying the downstream bearing 46, and a radially external end connected to the flange 34a.
[0051] The oil supply circuit 40 of the enclosure 38 is more clearly visible in [Fig.2] and includes an oil distributor 48 and at least one oil line 50. The oil distributor 48 is integral with the housing 36 and includes at least one oil inlet 48a and at least one first oil outlet 48b.
[0052] The oil inlet 48a is suitable for connection to an oil reservoir not shown.
[0053] The oil line 50 is integral with the first bearing support 32 and has an end 40a, here downstream, connected to the first oil outlet 48b of the distributor 48 for the purpose of circulating oil from said inlet 48a to said at least one outlet 48b.
[0054] In the example shown, the distributor 48 comprises two oil outlets 48b, 48c, the first oil outlet 48b mentioned above and a second oil outlet 48c. The second oil outlet 48c can be connected to another line or to an oil nozzle 52 as illustrated in the drawing. The nozzle 52 sprays oil onto the downstream bearing 46, while the line 50 connected to the first outlet 48b of the distributor 48 supplies oil to the upstream bearing 44 for lubrication.
[0055] Preferably, the first outlet 48b is oriented axially, in particular towards the first bearing support 32, i.e. here upstream. The second outlet 48c can be oriented radially inwards.
[0056] Figures 2 to 4 further show that the conduit 50 includes a part which extends axially and which passes through an axial orifice 54 of the second bearing support 34. The conduit 50 is radially interposed between the downstream bearing 46 and the flanges 32a, 34a of the bearing supports 32, 34.
[0057] Fig. 3 shows the default and normal operating case in which the flanges 32a of the bearing supports 32 are applied axially to each other and fixed together by the shear screws 42.
[0058] As mentioned above, in the event of imbalance and vibrations, the shear screws 42 are liable to break as illustrated in [Fig. 4]. The flange 32a of the first bearing support 32, and in particular the first bearing support 32 as a whole, is then no longer axially restrained and moves axially away from the second bearing support 32. The first bearing support 32 then moves upstream, creating an annular passage 56 between the flanges 32a, 34a of the bearing supports 32, 34.
[0059] The oil supplied by the distributor 48 continues to flow into the enclosure and accumulates there. This oil is then liable to flow by gravity through the passage 56 and can reach the primary vein VI, which is problematic as mentioned above.
[0060] The present invention offers a simple, effective and economical solution to this problem.
[0061] The invention is illustrated in [Fig.5] and relates to a module such as presented for example in the preceding text and which further comprises an annular flow channel for a gas flow.
[0062] In the example shown, the vein is the main annular vein referenced VI, carrying the first airflow or primary flow FL
[0063] This vein V1 extends around the axis A and the lubrication chamber 38.
[0064] In the example shown, the portion of the vein V1 which is visible in the drawing and extends around the enclosure 38 is that of the low pressure compressor 14 and the intermediate casing 20.
[0065] The rotor of the low-pressure compressor 14 comprises a drum 62 which carries several stages of rotor blades 64, these stages of rotor blades 64 being separated from each other by stages of stator blades 66. The rotor and stator blades 64, 66 radially traverse the VL channel
[0066] In a known manner, a drum 62 comprises an annular wall in the shape of a barrel around which are mounted several annular stages or rows of rotor blades 64. The rotor blades 64 comprise, for example, feet fitted into an annular groove 68 of the wall which opens radially outwards.
[0067] The drum 62 defines, at least in part, radially on the inside, the vein VI, and the rotor and stator blades 64, 66 are surrounded by an annular housing 70 which defines, at least in part, radially on the outside, this vein VL
[0068] At the intermediate compressor 20, the V1 flow is radially delimited internally by the central hub 22 or an annular wall 72 of this central hub, and radially externally by another annular wall 74. The radial arms 24 extend between the walls 72, 74 and cross the V1 flow
[0069] It can also be seen in [Fig. 5] that the module 30 may include conduits 76 and / or be traversed axially by conduits 76, in particular conduits that are connected to the aforementioned circuit 40. This is notably the case for conduits 76a which run axially along the bearing support 32, radially outside of it, and which pass through internal cavities of the radial arms 24.
[0070] According to the invention, an oil deflector 80 is interposed radially between the vein V1 and the enclosure 38. The deflector 80 is located substantially at the flanges 32a, 34a so that it is able to receive and guide the oil that may flow by gravity from the aforementioned passage 54 illustrated in [Fig.4], which would result from a breakage of the fusible screws 42 and an axial separation of the flanges 32a, 34a (arrows Z in [Fig.5]).
[0071] The deflector 80 may have a general curved shape around the axis A and have a predetermined angular extent around the axis A, which is for example between 30 and 100°.
[0072] The deflector 80 can be formed from a single piece.
[0073] The deflector 80 is preferably located in the lower part of the module 30, as illustrated in Figures 5 to 9, and is crossed in its middle by a plane passing through the axis A and at 6 o'clock by analogy with the face of a clock. This median plane P is the cutting plane of [Fig. 5].
[0074] Advantageously, the deflector 80 comprises a frustoconical wall portion 82. It may further comprise two radially external circumferential edges 84, 86, between which extends the portion of frustoconical wall 82. The rim 84 is an upstream rim, and the rim 86 is a downstream rim.
[0075] The deflector 80 may include at least one notch 88 for the passage of a conduit 76 of the module, such as an oil conduit of the circuit 40.
[0076] The deflector 80 can extend in a circumferential direction between two conduits 76 of the module 30, as illustrated in the drawings, such as two conduits 76a mentioned above.
[0077] The deflector 80 is preferably at least partially radially interposed between the enclosure 38 and the drum 62 and is configured to discharge the received oil radially into the interior of this drum 62. Indeed, as can be seen in [Fig. 5], the deflector 80, and in particular its wall 82, is axially flared from downstream to upstream. The oil is thus conveyed by the deflector from downstream to upstream into the interior of the drum 62, which naturally includes an internal annular pocket 90 that can be used for storing this oil (arrows Z).
[0078] The portion of frustoconical wall 82 is thus flared on the side of the drum 62. The upstream rim 84 of the deflector 80 is surrounded by the drum 62 and is preferably located upstream of a leek-shaped disc 92 of the drum 62.
[0079] The deflector 80 is moreover at least partly intercalated radially between the enclosure 38 and the aforementioned wall 72 of the housing 20. The downstream rim 86 of the deflector 80 is surrounded by this wall 72 and is preferably located downstream of the downstream axial ends of the pipes 76 and / or the pipes 76a.
[0080] It is therefore understood that under normal operating conditions, the shear screws 42 are not broken and the flanges 32a, 34a of the bearing supports 32, 34 are held axially clamped against each other. The deflector 80 is then not functional in the sense that it is "on standby". If the shear screws 42 break, the flanges 32a, 34a of the bearing supports 32, 34 will move axially apart and oil contained in the housing 38 is likely to flow by gravity through the passage 54 created between the flanges 32a, 34a. This oil will then be collected by the deflector 80, which will guide it to an area suitable for its accumulation and storage, such as the inside of the drum 62 in the example shown. This prevents contamination of vein V1 by this oil.
Claims
Demands
1. Module (30) for an aircraft turbomachine (10), said module (30) comprising: - a first annular bearing support (32) extending about an axis (A) and comprising a first annular mounting flange (32a), - a second annular bearing support (34) extending about the axis (A) and comprising a second annular mounting flange (34a), the first and second flanges (32a, 34a) being adapted to be axially pressed against each other and to be fastened together by shear screws (42), - an annular housing (20, 36) extending about the axis (A), the second bearing support (34) being fixed to the housing (20, 36), - a lubrication chamber (38) which is at least partially delimited by the first bearing support (32), this lubrication chamber (38) containing a first bearing housing (44) carried by the first bearing support (32) and a second bearing housing (46) carried by the second bearing support (34),and - an oil supply circuit (40) for the enclosure (38), - an annular gas flow channel (VI), this channel (VI) extending around the axis (A) and the lubrication enclosure (38), and - an oil deflector (80) which is radially interposed between the channel (VI) and the enclosure (38), and which is located substantially opposite the first and second flanges (32a, 34a), the deflector (80) being configured to receive and guide the oil likely to flow by gravity from an annular passage between the first and second flanges (32a, 34a) which would result from a failure of the shear screws (42) and an axial separation of the flanges.
2. Module (30) according to claim 1, wherein the deflector (80) has a general curved shape around the axis (A) and has a predetermined angular extent around the axis (A).
3. Module (30) according to claim 2, wherein the deflector (80) has an angular range between 30 and 100°.
4. Module (30) according to any one of the preceding claims, wherein the deflector (80) is located in the lower part of the module (3(0) and is crossed in its middle by a plane (P) passing through the axis (A) and at 6 o'clock by analogy with the face of a clock.
5. Module (30) according to any one of the preceding claims, wherein the deflector (80) comprises a frustoconical wall portion (82).
6. Module (30) according to the preceding claim, wherein the deflector (80) comprises two radially external circumferential rims (84, 86), between which extends the frustoconical wall portion (82).
7. Module (30) according to any one of the preceding claims, wherein the deflector (80) includes at least one notch (88) for the passage of a conduit (76) of the module, such as an oil conduit of said circuit.
8. Module (30) according to any one of the preceding claims, wherein the deflector (80) extends in a circumferential direction between two conduits (76) of the module, such as oil conduits.
9. Module (30) according to any one of the preceding claims, wherein the vein (VI) is at least partly delimited, radially inside, by a rotor drum (62) which carries rotor blade stages (64), the deflector (80) being at least partly interposed radially between the enclosure (38) and the drum (62) and being configured to discharge the oil received radially inside this drum (62).
10. Module (30) according to the preceding claim, depending on claim 6, wherein the frustoconical wall portion (82) is flared on the side of the drum (62) and one of said rims (64, 86) is surrounded by the drum (62).
11. Module (30) according to claims 9 or 10, wherein the vein (VI) is further at least partially delimited, radially inside, by an annular wall (72) of said housing (20), the deflector (80) being at least partially intercalated radially between the enclosure (38) and this wall (72).
12. Module (30) according to claim 11, when it depends on claim 10, wherein the other of said rims (84, 86) is surrounded by said wall (72) of the housing (20).
13. Module (30) according to any one of the preceding claims, wherein the flange (34a) of the second bearing support (34) is axially interposed between the flange (32a) of the first bearing support (32) and another flange (36a) of the housing (20, 36).
14. 12 Module (30) according to any one of the preceding claims, wherein the flange (34a) of the second bearing support (34) is fixed to a flange (36a) of the housing (20, 36) by non-fusible screws.
15. Turbomachine for an aircraft, comprising at least one module (30) according to any one of the preceding claims.