MODULE FOR AN AIRCRAFT TURBOMACHINE
The module with pressure sensors addresses the issue of oil leakage by detecting shear screw failure and closing the oil supply, ensuring safe operation of the turbomachine by preventing air contamination.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- SAFRAN AIRCRAFT ENGINES SAS
- Filing Date
- 2024-05-24
- Publication Date
- 2026-05-22
AI Technical Summary
Existing aircraft turbomachines face the risk of oil leakage into the primary flow channel due to the decoupling of bearing supports when shear screws fail, leading to contamination of the air intake with oil, which can result in polluted air supply to the aircraft.
A module with pressure sensors interposed between bearing support flanges is used to detect a pressure drop upon shear screw failure, triggering an emergency closure of the oil supply circuit to prevent oil leakage.
Prevents oil leakage into the engine by automatically shutting off the oil supply when shear screws break, thereby reducing the risk of air contamination and potential damage to the turbomachine.
Smart Images
Figure 00000011_0000 
Figure 00000012_0000 
Figure 00000012_0001
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 significant 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 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 flanges of the bearing supports, 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] - at least one pressure sensor interposed between the first and second flanges, and
[0020] - an electronic control circuit connected to at least one pressure sensor and said oil supply circuit, this electronic circuit being capable of commanding an emergency closure of said oil supply circuit when said at least one sensor detects a pressure below a predetermined threshold corresponding to a rupture of the fusible screws.
[0021] In normal operation, 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 pressure sensor, which is located between the bearing support mounting flanges, then detects a pressure drop. This information is relayed to the control circuit, which can then close the oil supply circuit. The housing is then no longer supplied with oil, thus limiting the risk of oil leakage into the engine.
[0022] The module according to the invention may comprise one or more of the following features, taken individually or in combination with each other: • said at least one sensor is interposed between facing radial faces, in particular axially, of the first and second flanges;
[0023] — the radial faces are axially oriented; • the module includes at least two, three or four pressure sensors regularly distributed around the axis; • said at least one pressure sensor is flat and extends in a radial plane with respect to the axis; • said at least one pressure sensor is connected by wire to said electronic circuit; • said at least one pressure sensor is wirelessly connected to said electronic circuit; • 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 a flange of the casing by non-shear screws;
[0024] — the electronic circuit is capable of controlling an emergency closure of a oil distributor of said supply circuit;
[0025] — the number of sensors is equal to the number of fusible screws;
[0026] — the pressure measured by the pressure sensor corresponds to the applied pressure between the flanges by the shear screws and therefore depends in particular on the tightening torque of the flanges by the shear screws.
[0027] The present invention also relates to an aircraft turbomachine, comprising at least one module as described above. Brief description of the figures
[0028] 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:
[0029] [Fig-1] [Fig.1] is a schematic half-view in axial section of a part of a aircraft turbomachine,
[0030] [Fig.2] [Fig.2] is a partial schematic axial cross-sectional view of a bearing lubrication chamber,
[0031] [Fig.3] [Fig.3] is a larger-scale view of part of [Fig.2] and shows a decoupling device comprising fusible screws which are here unbroken,
[0032] [Fig.4] [Fig.4] is a view similar to that of [Fig.3] and shows the decoupling device with fusible screws here broken,
[0033] [Fig.5] [Fig.5] is a schematic axial cross-sectional view of a pressure sensor interposed between the bearing support flanges, and illustrates one embodiment of the invention,
[0034] [Fig.6] [Fig.6] is a perspective view of a pressure sensor which can be used in the context of the present invention. 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 flow of gases along axis A, a LP or low pressure compressor 14, an HP or high pressure compressor, an annular combustion chamber, an HP or high pressure turbine and a LP or low pressure turbine. The turbomachine 10 is partially represented and only the BP 14 compressor is shown 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] Fig. 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 proposes to equip the module 30 with at least one pressure sensor 60 interposed between the first and second flanges 32a, 34a, and to connect the pressure sensor(s) 60 to an electronic control circuit 62 for the oil supply circuit 40.
[0062] The pressure sensor or each pressure sensor 60 is preferably interposed between the radial faces 32al, 34al facing axially the flanges 32a, 34a.
[0063] [Fig.6] shows a non-limiting example of a pressure sensor 60. The or each pressure sensor 60 may be flat and may extend in a radial plane with respect to the aforementioned axis A, as illustrated in [Fig.5].
[0064] The pressure sensor technology is for example of the strain gauge type or of the FSR type which has an ohmic resistance which decreases when pressure or force is applied to it or of the fiber optic pressure sensor type.
[0065] The module 30 may include at least two, three or four pressure sensors 60 which are preferably regularly distributed around the axis A. The number of pressure sensors 60 may be equal to the number of fusible screws 42 for example.
[0066] Each of the pressure sensors 60 can be located as close as possible to one of the shear screws 42. The pressure sensors 60 can, for example, be located in radial planes passing through the axis A and through the shear screws 42.
[0067] The pressure sensor or each pressure sensor 60 can be connected to the control circuit 62 by wired or wireless connection.
[0068] The control circuit 62 is capable of triggering an emergency shutdown of the oil supply circuit 40 when the sensor(s) 60 detect a pressure below a predetermined threshold corresponding to a failure of the shear screws 42. The pressure measured by the sensor(s) 60 corresponds to the pressure applied between the flanges 32a, 34a by the fusible screws 42 and therefore depends in particular on the tightening torque of the flanges 32a, 34a by the fusible screws 42.
[0069] The control circuit 62 is for example configured to control the movement of a moving part in the distributor 48, in a position where this part closes for example the outlets 48b, 48c of the distributor 48.
[0070] Under normal operating conditions, the shear screws 42 hold the flanges 32a, 34a of the bearing supports 32, 34 together. The pressure sensors 60 do not detect any pressure loss, and the circuit 40 supplies oil to the enclosure 38. If the shear screws 42 break, the pressure sensors 60 detect a pressure drop and send a corresponding signal to the control circuit 62, which will then control the circuit 42 to shut off the oil supply to the enclosure 38.
Claims
Demands
1. A module (30) for an aircraft turbomachine (10), said module (30) comprising: - a first annular bearing support (32) extending about an axis (A) and including a first annular mounting flange (32a), - a second annular bearing support (34) extending about the axis (A) and including 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 (36) extending about the axis (A), the second bearing support (34) being fixed to the housing (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 support (44) carried by the first bearing support (32) and a second bearing support (46) carried by the second bearing support (34),- an oil supply circuit (40) for the enclosure (38), - at least one pressure sensor (60) interposed between the first and second flanges (32a, 34a), and - an electronic control circuit (62) connected to said at least one pressure sensor (60) and said oil supply circuit (40), this electronic circuit (62) being capable of triggering an emergency closure of said oil supply circuit (40) when said at least one sensor (60) detects a pressure below a predetermined threshold corresponding to a rupture of the shear screws (42).
2. Module (30) according to claim 1, wherein said at least one sensor (60) is intercalated between radial faces (32a 1, 34a 1) opposite the first and second flanges (32a, 34a).
3. Module (30) according to claim 1 or 2, wherein it comprises at least two, three or four pressure sensors (60) regularly distributed around the axis (A).
4. Module (30) according to any one of the preceding claims, wherein said at least one pressure sensor (60) is flat and extends in a radial plane with respect to the axis (A).
5. Module (30) according to any one of claims 1 to 4, wherein said at least one pressure sensor (60) is connected by wire to said electronic circuit.
6. Module (30) according to any one of claims 1 to 4, wherein said at least one pressure sensor (60) is wirelessly connected to said electronic circuit.
7. 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 (36).
8. 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 (36) by non-fusible screws.
9. Turbomachine (10) for an aircraft, comprising at least one module (30) according to any one of the preceding claims.