Module for an aircraft turbine engine with a circuit for supplying oil to the lubrication chamber

Abstract

The invention relates to a module (30) for an aircraft turbine engine (10), this module (30) including: - a lubrication chamber (38) which is at least partially delimited by bearing supports (32, 34); - a circuit (40) for supplying oil to the chamber (38); and - an annular sealing skirt (80) which comprises a first axial end (80a) sealingly attached to the first bearing support (32) and a second axial end (80b) sealingly attached to the second bearing support (34), the skirt (80) being made of a deformable material and being able to provide a seal around flanges (32a, 34a) of the bearing supports (32, 34), in particular in the event of a rupture of frangible bolts (42) for attaching these bearing supports (32, 34).

Description

[0001] DESCRIPTION

[0002] MODULE FOR AN AIRCRAFT TURBOMACHINE WITH OIL SUPPLY CIRCUIT FOR THE LUBRICATION CABINET

[0003] Technical field of the invention

[0004] The present invention relates to a module for an aircraft turbomachine, as well as a turbomachine comprising such a module.

[0005] Technical background

[0006] The prior art includes in particular the document EP-B1-2 721 260, FR-A1- 2 888 621, EP-B1-2 071 141, FR-A1-2 752 024, US-A1 -2009 / 185768 and CN-A- 112 049 814.

[0007] An aircraft turbomachine includes a gas generator which classically comprises, from upstream to downstream, with reference to the flow of gases in the turbomachine, at least one compressor, one annular combustion chamber and at least one turbine.

[0008] 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.

[0009] The high-pressure compressor rotor is connected to the high-pressure turbine rotor by a high-pressure shaft. The low-pressure compressor rotor is connected to the low-pressure turbine rotor by a low-pressure shaft that passes through the high-pressure shaft and drives a propeller shaft, typically located upstream of the gas generator.

[0010] When this propeller is enclosed and therefore surrounded by an annular casing, this propeller is called a blower and generates an airflow, called secondary flow, which flows around the gas generator.

[0011] The propeller shaft and the low-pressure shaft are guided by bearings housed within a lubrication chamber. This chamber is surrounded by the first lubrication channel and is at least partially defined 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 radially oriented annular flanges that are axially pressed against each other and against an annular flange on a stator housing.

[0012] The lubrication chamber is designed to lubricate the bearings and maintain an oily atmosphere around them. Oil is supplied to the chamber via a supply circuit.

[0013] The propeller includes blades that are susceptible to breakage, although this is extremely rare. In such a case, a significant imbalance occurs on the propeller shaft, generating cyclic loads and vibrations that the upstream bearing transmits to the stator, with a considerable risk of damage.

[0014] To limit the forces transmitted to the stator in the presence of significant imbalance, a shear screw decoupling device is described in 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.

[0015] 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.

[0016] 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.

[0017] This phenomenon is problematic because the enclosure continues to be supplied with oil by the aforementioned circuit, and the oil accumulating within it 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 intake channel from which air is drawn to supply the aircraft equipped with the turbomachine. There is therefore a risk that the aircraft will be supplied with polluted air, potentially containing fumes and unpleasant odors. Furthermore, there is currently no effective solution for retaining the shear bolts after they break, so it is possible that the bolts could remain in the enclosure below the intake channel, unattached to their original supports.

[0018] The invention offers an improvement which makes it possible to provide a solution to at least some of the problems mentioned above.

[0019] Summary of the invention

[0020] The invention relates to a module for an aircraft turbomachine, this module comprising:

[0021] - a first annular bearing support extending around an axis and comprising a first annular fixing flange,

[0022] - a second annular bearing support extending around the axis and comprising a second annular mounting flange, the first and second flanges being applied axially against each other and fixed together by shear screws,

[0023] - an annular housing that extends around the axis, the second bearing support being fixed to the housing,

[0024] - a lubrication enclosure which is at least partially 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

[0025] - an oil supply circuit for the enclosure, and

[0026] - an annular sealing skirt which extends around the first and second flanges and which includes a first axial end fixed in a sealed manner to the first bearing support and a second axial end fixed in a sealed manner to the second bearing support, this skirt being made of a deformable material and being suitable for ensuring a seal around the flanges, between the first and second bearing supports in particular in the event of breakage of the shear screws.

[0027] Under normal operating conditions, shear bolts ensure the axial retention of the first bearing support relative to the second bearing support. Although the skirt provides a seal around the flanges, this seal is not strictly necessary at this stage, as the flanges may be equipped with their own sealing system. If the shear bolts fail, the bearing supports separate and move axially apart. The skirt then provides a seal around the flanges and is deformable to absorb the relative movements between the bearing supports. Therefore, there is no risk of oil leaking into the engine, as the oil remains contained by the skirt.

[0028] The module according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0029] - the skirt is made of elastically deformable material;

[0030] - the skirt is made of elastomer;

[0031] - the first end of the skirt is fixed to an annular rib of the first bearing support, this rib extending radially outwards;

[0032] - the first end of the skirt is oriented radially outwards so that a free peripheral edge of this end is oriented radially outwards;

[0033] - the first end of the skirt is pressed against an annular face of the rib by means of an annular plywood;

[0034] - the plywood is fixed to the rib by screws which go through holes in the rib, the end of the skirt and the plywood;

[0035] - the second end of the skirt is attached to the flange of the second bearing support;

[0036] - the second end of the skirt is radially clamped onto the flange by means of a clamping collar which surrounds the flange;

[0037] - the clamping collar comprises at least two angular sectors which are arranged end to end and which include at their ends lugs for fixing the sectors together, the lugs of two adjacent sectors being fixed together by fixing elements such as screws;

[0038] - the hose clamp is a perforated band clamp and includes a screw whose tightening and loosening allows adjustment of the internal diameter of the clamp;

[0039] - the flange of the second bearing support is axially interposed between the flange of the first bearing support and another flange of the housing;

[0040] - the flange of the second bearing support is fixed to the flange of the casing by non-shear screws;

[0041] - the skirt has a generally domed shape with a concavity oriented radially inwards, when the fusible screws are not broken;

[0042] - the skirt defines a free annular cavity around at least part of the first bearing support and / or the second bearing support; -- the skirt is fiber-loaded;

[0043] -- the fibers are oriented in the axial direction, which allows the skirt to have a capacity for deformation in bending and a hardness in tension.

[0044] - one of the bearing supports carries a retaining ring which extends around this bearing support and at least partly around the shear screws, and in particular their heads, and which is capable of retaining at least part of these shear screws in the event of breakage of the shear screws.

[0045] Under normal operating conditions, the 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. Portions of the shear screws may then detach from the bearing supports. At least some of these portions can be retained by the ring according to the invention, which is attached to one of the bearing supports. The risk of these shear screw portions entering the motor shaft is therefore limited.

[0046] The first and second bearing supports can support the same bearing or different bearings, or be connected to the same bearing or different bearings.

[0047] The module according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0048] -- each shear screw comprises a head connected to a threaded rod;

[0049] - the threaded rod is screwed into a separate nut or screwed into a tapped hole;

[0050] - the retaining ring is formed by a sheet of metal;

[0051] - the retaining ring comprises a first axial end fixed to the bearing support which carries it, and a second opposite axial end which is free and is located at a radial distance from this bearing support;

[0052] -- the first end of the ring is fixed to the bearing support by axial screws which pass through holes in this first end and in the bearing support;

[0053] -- the first end of the ring is fixed to an annular rib of the first bearing support, this rib extending radially outwards;

[0054] -- the first end of the ring is oriented radially inwards so that a free peripheral edge of this end is oriented radially inwards;

[0055] - the retaining ring has a general L-shape and comprises a first radial wall connected to the bearing support which carries it, and a second cylindrical wall which extends axially from the outer periphery of the first wall and around at least part of the shear screws;

[0056] -- the annular sealing skirt extends around the retaining ring

[0057] -- the first end of the skirt is crossed by the screws for fixing the ring to the first bearing support;

[0058] -- the module further includes an annular housing that extends around the axis, the second bearing support being fixed to the housing

[0059] The present invention also relates to an aircraft turbomachine, comprising at least one module as described above.

[0060] Brief description of the figures

[0061] 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 attached drawings in which:

[0062] [Fig.1] Figure 1 is a schematic half-view in axial cross-section of part of an aircraft turbomachine,

[0063] [Fig.2] Figure 2 is a partial schematic axial cross-sectional view of a bearing lubrication chamber,

[0064] [Fig. 3] Figure 3 is a larger-scale view of part of Figure 2 and shows a decoupling device with fusible screws, here unbroken. [Fig. 4] Figure 4 is a view similar to that of Figure 3 and shows the decoupling device with fusible screws, here broken.

[0065] [Fig. 5] Figure 5 is a schematic axial cross-sectional view of a sealing skirt, and illustrates one embodiment of the invention.

[0066] [Fig. 6] Figure 6 is a view similar to that of Figure 5 and shows the sealing skirt in case of breakage of the fusible screws,

[0067] [Fig.7] Figure 7 is a schematic perspective view of a hose clamp for fixing one of the axial ends of the skirt;

[0068] [Fig.8a-8b] Figures 8a and 8b are schematic views of another clamp for securing one of the axial ends of the skirt.

[0069] [Fig. 9] Figure 9 is a schematic axial cross-sectional view of a module according to an embodiment of the invention, [Fig. 10a-1 Ob] Figures 10a and 10b are larger-scale detailed views of Figure 9 and show, respectively, axial ends of a retaining ring of the module, and

[0070] [Fig.11] Figure 11 is a view similar to that of Figure 9 and shows the module in case of breakage of the fusible screws.

[0071] Detailed description of the invention

[0072] Figure 1 shows a turbomachine 10 for an aircraft, this turbomachine 10 being here a twin-spool turbojet.

[0073] Axis A designates the longitudinal axis of the turbomachine.

[0074] 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.

[0075] Although not visible in Figure 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 surrounded by an annular casing called a blower casing 18.

[0076] 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.

[0077] The gas generator 12 defines a main annular flow channel V1 for a first air flow, called the primary flow F1. The gas generator 12 is surrounded by a secondary annular flow channel V2 for a second air flow, called the secondary flow F2.

[0078] The airflow F entering the blower 16 splits into two parts: one forming the primary flow F1, and the other the secondary flow F2, which is then mixed with fuel and burned in the combustion chamber. The combustion gases from the primary flow are subsequently expanded in the HP and BP turbines and finally exit through an exhaust nozzle. The remaining portion of the airflow entering the blower 16 forms the secondary flow F2 and is intended to be mixed with the primary flow F1 downstream of the nozzle.

[0079] 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.

[0080] A first annular bearing support 32 extends around the axis A and includes a first annular fixing flange 32a, more clearly visible in figure 2.

[0081] A second annular bearing support 34 extends around the axis A and includes a second annular fixing 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.

[0082] 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 bolts and are not shown in the drawings. The shear bolts 42 and the non-shear bolts may be located on the same circumference centered on axis A. The housing 36 may be the intermediate housing 20 of Figure 1 or another housing fixed to or integral with this intermediate housing 20.

[0083] The housing 36 includes a flange 36a onto which the flange 34a is applied and secured 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.

[0084] 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.

[0085] In the example shown, the upstream bearing 44 is a roller bearing and the downstream bearing 46 is a ball bearing.

[0086] Furthermore, in the example shown, the first bearing support 32 has a generally annular shape and is elongated along axis A. It 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. The oil supply circuit 40 for the housing 38 is more clearly visible in Figure 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.

[0087] The oil inlet 48a is suitable for connection to an oil reservoir not shown.

[0088] 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.

[0089] In the example shown, the distributor 48 comprises two oil outlets 48b and 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.

[0090] Preferably, the first outlet 48b is oriented axially, specifically towards the first bearing support 32, i.e., upstream in this case. The second outlet 48c can be oriented radially inwards.

[0091] 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.

[0092] Figure 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.

[0093] Each screw 42 comprises a head 42a and a threaded shank 42b, one axial end of which is connected to the head 42a. The threaded shank 42b of the screw 42 can be screwed into a tapped hole or into a nut 43 as in the example shown.

[0094] As mentioned above, in the event of imbalance and vibrations, the shear screws 42 are liable to break as illustrated in figure 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 retained and moves axially away from the second bearing support 32. The first bearing support 32 then moves upstream which creates an annular passage 56 between the flanges 32a, 34a of the bearing supports 32, 34.

[0095] The oil supplied by distributor 48 continues to flow into the enclosure and accumulates there. This oil is then likely to flow by gravity through passage 56 and can reach the primary vein V1, which is problematic as mentioned above.

[0096] Furthermore, pieces of the broken fusible screws 42 (including for example the heads 42a) are likely to separate in particular from the flange 32a and pass into the enclosure under the engine's flow which surrounds the lubrication enclosure 38 and it is important to prevent the screws from causing damage.

[0097] The present invention offers a simple, effective and economical solution to at least some of the aforementioned problems.

[0098] The invention proposes to provide a solution for containing the oil inside the enclosure 38, even when the screws 42 break and the bearing supports 32, 34 move axially apart from each other.

[0099] As illustrated in figures 5 and 6, the invention thus proposes an annular sealing skirt 80 which extends around the flanges 32a, 34a and which includes a first axial end 80a fixed in a sealed manner to the first bearing support 32 and a second axial end 80b fixed in a sealed manner to the second bearing support 34.

[0100] The skirt 80 is made of a deformable material, preferably elastically deformable, such as an elastomer. For example, the skirt 80 is made of Viton®.

[0101] The skirt 80 is preferably fiber-reinforced. The fibers are preferably oriented in the axial direction so that the skirt 80 has a bending deformation capacity and tensile strength.

[0102] The skirt 80 is suitable for ensuring a seal around the flanges 32a, 34a, between the first and second bearing supports 32, 34 in particular in the event of breakage of the shear screws 42 (figure 6).

[0103] In the example shown, the skirt 80 has a generally convex shape with a concavity oriented radially inwards when the shear screws 42 are not broken (Figure 5). The skirt 80 can define a free annular cavity 82 around at least part of the bearing support 32 and / or the bearing support 34. In the example shown, the first end 80a of the skirt 80 is fixed to an annular rib 84 of the first bearing support 32. This rib 84 extends radially outwards, here at an axial distance from the flange 32a.

[0104] The first end 80a of the skirt 80 can be oriented radially outwards so that a free peripheral edge 80a1 of this end 80a is oriented radially outwards.

[0105] The first end 80a of the skirt 80 is pressed against an annular face 84a, here downstream, of the rib 84 by means of an annular plywood 86. This plywood 86 can be sectored to facilitate its assembly.

[0106] The plywood 86 is fixed to the rib 84 by screws 87 which pass through holes in the rib 84, the end 80a of the skirt 80 and the plywood 86.

[0107] The plywood 86 may include a cylindrical rim 86a which surrounds the edge 80a of the end 80a or also a free peripheral edge 84a1 of the rib 84.

[0108] In the example shown, the second end 80b of the skirt 80 is fixed to the flange 34a of the second bearing support 34.

[0109] The second end 80b of the skirt 80 can be radially clamped onto the flange 34a by means of a clamping collar 88 which surrounds the flange 34a.

[0110] In the embodiment of Figure 7, the clamping collar 88 comprises at least two angular sectors 88a, 88b arranged end to end and having at their ends lugs 90 for securing the sectors 88a, 88b together. The lugs 90 of two adjacent sectors 88a, 88b are secured together by fasteners such as screws 92 that pass through holes in the lugs 90, for example.

[0111] In the embodiment variant of figures 8a and 8b, the clamping collar 88 is a collar with an openwork band and includes a screw 94 whose screwing-unscrewing allows adjustment of the internal diameter of the collar 88.

[0112] In normal operation, the skirt 80 is in the configuration shown in Figure 5 and is not functional. It is in standby mode. When the screws 42 break and the bearing support 32 moves axially away from the bearing support 34, the skirt 80 is in the configuration shown in Figure 6 and is functional. The skirt 80 then provides a seal between the flanges 32a and 34a, and any oil that might pass through the passage 56 between the flanges 32a and 34a is retained by the skirt 80 and does not escape from the housing 38. In the embodiment shown in Figures 9 to 11, one of the bearing supports 32 carries a retaining ring 86 that extends around this bearing support 32 and at least partially around the shear screws 42, and in particular their heads 42a.

[0113] The retaining ring 86 is suitable for retaining at least a part (in particular those containing the heads 42a) of the shear screws 42 in the event of breakage of the shear screws 42, and in particular the pieces of broken screws located on the side of the bearing support 32 and the retaining ring 86.

[0114] The retaining ring 86 can be formed from a sheet metal, as in the example shown.

[0115] In this example, the retaining ring 86 comprises a first axial end 86a fixed to the bearing support 32 which carries it, and a second opposing axial end 86b which is free and which is located at a radial distance from this bearing support 32. The first end 86a of the ring 86 can be fixed to the bearing support 32 by axial screws 87 which pass through holes in this first end 86a and in the bearing support 32. The first end 86a of the ring 86 is here fixed to an annular rib 84 of the first bearing support 32, this rib 84 extending radially outwards.

[0116] The first end 86a of the ring 86 can be oriented radially inwards so that a free peripheral edge 86a1 of this end 86a is oriented radially inwards.

[0117] The retaining ring 86, for example, has a general L-shape and comprises a first radial wall 87a connected to the bearing support 32 which carries it, and a second cylindrical wall 87b which extends axially from the outer periphery of the first wall 87a and around at least part of the shear screws 42.

[0118] The annular sealing skirt 80 which preferably extends around the retaining ring 86.

[0119] The first end 80a of the skirt 80 can be oriented radially inwards so that a free peripheral edge 80a1 of this end 80a is oriented radially inwards.

[0120] The first end 80a of the skirt 80 is axially intercalated between the rib 84 and the first end 86a of the retaining ring 86, which thus forms a plywood.

[0121] The first end 80a of the skirt 80 is preferably crossed by the screws 87 for fixing the ring 86 to the first bearing support 32. As mentioned above, the module according to the invention may further include a lubrication chamber 38.

[0122] The retaining ring 86 ensures the retention of fragments of fusible screws that detach from the flange 32a (figure 11). These fragments are liable to come into contact with the skirt 80 and damage it; therefore, the retaining ring 86 also provides protection for the skirt 80 when used in conjunction with a skirt as in the example shown.

Claims

DEMANDS 1. Module (30) for an aircraft turbomachine (10), this module (30) comprising: - a first annular bearing support (32) which extends around an axis (A) and which includes a first annular fixing flange (32a), - a second annular bearing support (34) which extends around the axis (A) and which includes a second annular fixing flange (34a), the first and second flanges (32a, 34a) being applied axially against each other and fixed together by shear screws (42), - an annular housing (36) which extends around the axis (A), the second bearing support (34) being fixed to the housing (36), - a lubrication enclosure (38) which is at least partly delimited by the first bearing support (32), this lubrication enclosure (38) containing a first bearing (44) carried by the first bearing support (32) and a second bearing (46) carried by the second bearing support (34), - an oil supply circuit (40) for the enclosure (38), and - an annular sealing skirt (80) which extends around the first and second flanges (32a, 34a) and which includes a first axial end (80a) fixed in a hermetic manner to the first bearing support (32) and a second axial end (80b) fixed in a hermetic manner to the second bearing support (34), this skirt (80) being made of a deformable material and being suitable for ensuring a seal around the flanges (32a, 34a), between the first and second bearing supports (32, 34) in particular in the event of breakage of the shear screws (42).

2. Module (30) according to claim 1, wherein the skirt (80) is made of elastically deformable material.

3. Module (30) according to claim 2, wherein the skirt (80) is made of elastomer.

4. Module (30) according to any one of the preceding claims, wherein the first end (80a) of the skirt (80) is fixed to an annular rib (84) of the first bearing support (32), this rib (84) extending radially outwards.

5. Module (30) according to claim 4, wherein the first end (80a) of the skirt (80) is oriented radially outwards such that an edge free peripheral (80a1) of this end (80a) is oriented radially outwards.

6. Module (30) according to claim 4 or 5, wherein the first end (80a) of the skirt (80) is clamped against an annular face (84a) of the rib (84) by means of an annular plywood (86).

7. Module (30) according to claim 6, wherein the plywood (86) is fixed to the rib (84) by screws (87) which pass through holes in the rib (84), the end (80a) of the skirt (80) and the plywood (86).

8. Module (30) according to claim 6 or 7, wherein the second end (80b) of the skirt (80) is fixed to the flange (34a) of the second bearing support (34).

9. Module (30) according to claim 8, wherein the second end (80b) of the skirt (80) is radially clamped onto the flange (34a) by means of a clamping collar (88) which surrounds the flange (34a).

10. Module (30) according to claim 9, wherein the clamping collar (88) comprises at least two angular sectors (88a, 88b) which are arranged end to end and which comprise at their ends lugs (90) for fixing the sectors (88a, 88b) together, the lugs (90) of two adjacent sectors (88a, 88b) being fixed together by fixing elements (92) such as screws.

11. Module (30) according to claim 9, wherein the clamping collar (88) is a collar with an openwork band and includes a screw (94) whose screwing-unscrewing allows adjustment of the internal diameter of the collar.

12. 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).

13. 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.

14. Module (30) according to any one of the preceding claims, wherein the skirt (80) has a generally domed shape with a concavity oriented radially inwards, when the fusible screws (42) are not broken.

15. Module (30) according to any one of the preceding claims, wherein the skirt (80) defines a free annular cavity (82) around at least a portion of the first bearing support (32) and / or the second bearing support (34).

16. Module (30) according to any one of the preceding claims, wherein one of the bearing supports (32) carries a retaining ring (86) which extends around this bearing support (32) and at least partly around the shear screws (42), and in particular their heads, and which is capable of retaining at least part of these shear screws (42) in the event of breakage of the shear screws (42).

17. Module (30) according to claim 16, in which the retaining ring (86) is formed by a sheet.

18. Module (30) according to claim 16 or 17, wherein the retaining ring (86) comprises a first axial end (86a) fixed to the bearing support (32) which carries it, and a second opposite axial end (86b) which is free and is located at a radial distance from this bearing support (32) 19. Module (30) according to any one of claims 16 to 18, wherein the retaining ring (86) has a general L-shape and comprises a first radial wall (87a) connected to the bearing support (32) which carries it, and a second cylindrical wall (87b) which extends axially from the outer periphery of the first wall (87a) and around at least a portion of the fusible screws (42).

20. Turbomachine (10) for an aircraft, comprising at least one module (30) according to any one of the preceding claims.

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