Module for an aircraft turbine engine, comprising an oil supply circuit for the lubrication chamber

Abstract

The invention relates to a module (30) for an aircraft turbine engine (10), the module (30) comprising: - a first annular bearing support (32) which extends about an axis (A) and which comprises a first annular attachment flange (32a), - a second annular bearing support (34) which extends about the axis (A) and which comprises a second annular attachment flange (34b), the first and second flanges (32a, 34a) being able to be applied axially against one another and to be attached to one another by fusible screws (42), and - a circuit (40) for supplying oil to the chamber (38), this circuit (40) comprising an oil distributor (48) further comprising a member (60) capable of moving as soon as a breakage of the fusible screws (42) occurs.

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 documents EP-B1-2 721 260, FRAI -2 824 127, EP-B1-2 071 141 , EP-B1-1 662 636, US-B1-6,312,215 and EP-B1- 2 971 688.

[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 tensile mechanical 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 first bearing support when it is separated from the second bearing support.

[0017] This phenomenon is problematic because the housing 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 primary air intake, 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, or even with unpleasant fumes and odors. The invention relates to a technical solution aimed at eliminating the risk of oil leakage into the primary air intake after the bearing supports are decoupled from the lubrication housing.

[0018] Summary of the invention

[0019] The invention relates to a module for an aircraft turbomachine, this module comprising:

[0020] - a first annular bearing support extending around an axis and comprising a first annular fixing flange,

[0021] - a second annular bearing support extending around the axis and comprising a second annular fixing flange, the first and second flanges being suitable for axial application against each other and for being fixed together by shear screws,

[0022] - an annular housing that extends around the axis, the second bearing support being fixed to the housing,

[0023] - 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

[0024] - an oil supply circuit for the enclosure, this circuit comprising an oil distributor attached to the crankcase and comprising at least one oil inlet and at least one oil outlet, the distributor comprising a body having an internal cavity which is connected to said inlet and said outlet, the distributor further comprising a member housed in said cavity and movable from a first position in which it permits fluid communication between the inlet and the outlet, and a second position in which it prohibits fluid communication between the inlet and the outlet, the member being mechanically connected to one of said shear screws, the distributor further being configured so that the member adopts its first position in normal operation when the shear screws are not broken, and that the member adopts its second position when the shear screws have broken.

[0025] Under 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 shear screw failure will cause the oil distributor to automatically close, thus shutting off the oil supply circuit to the housing. This is because one of the shear screws is mechanically connected to the distributor's moving element, holding it in the open position during normal operation. The failure of this shear screw causes the element to move to the closed position, cutting off the oil supply to the housing. This interruption of the housing's oil supply limits the risk of oil leakage between the flanges and contamination of the engine's first oil passage.The module according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0026] - the organ is forced into its second position by a returning element such as a spring;

[0027] - the component forms a valve or drawer of the distributor;

[0028] - the organ has a general piston shape and comprises a cylindrical body connected to a rod;

[0029] - the component is directly connected to one of the shear screws and in particular to a threaded part of this shear screw;

[0030] - one end of the rod is connected to the threaded part;

[0031] - the component and the fusible screw are coaxial;

[0032] - the distributor, and in particular its body, is fixed to the second flange;

[0033] - the flange of the second bearing support is axially interposed between the flange of the first bearing support and a flange of the housing;

[0034] - the flange of the second bearing support is fixed to the flange of the casing by non-shear screws;

[0035] -- the distributor is of the hydraulic type.

[0036] The present invention also relates to an aircraft turbomachine, comprising at least one module as described above.

[0037] Brief description of the figures

[0038] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for the understanding of which reference should be made to the accompanying drawings in which: [Fig. 1] Figure 1 is a schematic half-view in axial section of a part of an aircraft turbomachine,

[0039] [Fig.2] Figure 2 is a partial schematic axial cross-sectional view of a bearing lubrication chamber,

[0040] [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.

[0041] [Fig. 5] Figure 5 is a very schematic axial cross-sectional view of an oil distributor comprising a movable element located in a first position, and illustrates one embodiment of the invention, and

[0042] [Fig.6] Figure 6 is a view similar to that of Figure 5 and shows the oil distributor with the moving part located in a second position.

[0043] Detailed description of the invention

[0044] Figure 1 shows a turbomachine 10 for an aircraft, this turbomachine 10 being here a twin-spool turbojet.

[0045] Axis A designates the longitudinal axis of the turbomachine.

[0046] 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.

[0047] 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.

[0048] 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. The gas generator 12 defines a main annular flow channel V1 for a first airflow, called the primary flow F1. The gas generator 12 is surrounded by a secondary annular flow channel V2 for a second airflow, called the secondary flow F2.

[0049] The airflow F entering the blower 16 splits into a portion forming the primary flow F1. The air in this primary flow F1 is compressed in the BP 14 and HP compressors, then mixed with fuel and burned in the combustion chamber. The combustion gases from the primary flow are then expanded in the HP and BP turbines and finally flow through an exhaust nozzle.

[0050] 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 F1 downstream of the nozzle.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] In the example shown, the upstream bearing 44 is a roller bearing and the downstream bearing 46 is a ball bearing.

[0058] Furthermore, in the example shown, the first bearing support 32 has a generally annular and elongated shape along 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.

[0059] The oil supply circuit 40 for the enclosure 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.

[0060] The oil inlet 48a is suitable for connection to an oil reservoir not shown.

[0061] The oil line 50 is integral with the first bearing support 32 and has an end 50a, 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.

[0062] 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.

[0063] 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.

[0064] Figures 2 to 4 further show that the conduit 50 includes a portion which extends axially and 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. Figure 3 shows the default configuration and normal operating condition in which the flanges 32a of the bearing supports 32 are axially applied to one another and fixed together by the shear screws 42.

[0065] 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.

[0066] The oil supplied by distributor 48 continues to flow into the enclosure and accumulates there. This oil is then likely to flow by gravity or centrifugal force through passage 56 and can reach the primary vein V1, which is problematic as mentioned above.

[0067] The present invention offers a simple, effective and economical solution to this problem.

[0068] The invention provides a particular distributor 48, one embodiment of which is illustrated in figures 5 and 6.

[0069] The oil distributor 48 has a single 48b outlet in the example shown, although it could include more.

[0070] Fluid communication between the inlet 48a and the outlet 48b of the distributor 48 is allowed or prohibited by means of a movable element 60 in the distributor 48. This element 60 forms a valve or a spool.

[0071] The distributor 48 comprises a body 62 having an internal cavity 64 which is connected to the inlet 48a and the outlet 48b. The member 60 is housed in the cavity 64 and is movable in this cavity 64 from a first position in which it allows fluidic communication between the inlet 48a and the outlet 48b (figure 5), and a second position in which it prohibits fluidic communication between the inlet 48a and the outlet 48b (figure 6).

[0072] The distributor 48 is further configured so that the element 60 assumes its first position in normal operation when the shear screws 42 are intact (Figure 5), and that the element 60 assumes its second position when the shear screws 42 have broken (Figure 6). The operation of the distributor 48 is hydraulic. This is made possible by the fact that the element 60 is mechanically connected to one of said shear screws 42, as illustrated in the drawings. The element 60 can be forced into its second position by a return element 70, such as a spring.

[0073] In the example shown, the component 60 has a general piston shape and comprises a cylindrical body 60a connected to a rod 60b. The return element 70 is mounted around the rod 60b and bears against the cylindrical body 60a to force it towards one end of the body 62 where the inlet 48a and the outlet 48b are located.

[0074] Advantageously, the component 60 is directly connected to the shear screw 42 and, in particular, to a threaded portion 42a of this shear screw 42. One end of the rod 60b can be connected to the threaded portion 42a. For example, the free end of the rod 60b can be screwed into a tapped hole 72 formed in the free end of the threaded portion 42a.

[0075] The component 60 and the fusible screw 42 are coaxial, which reduces the overall size and facilitates the actuation of component 60.

[0076] The distributor 48, and in particular its body 62, can be fixed to the flange 36a of the housing 36 on which the flange 34a is fixed by the aforementioned non-felt screws (not shown).

[0077] It is therefore understood that, in normal operation, component 60 is in its first position and distributor 48 remains open to supply chamber 38. If a breakage of the shear screws 42 occurs, component 60 automatically moves to its second position and closes distributor 48, which no longer supplies oil to chamber 38. The risk of oil leakage into the engine is thus limited.

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) 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 chamber (38) which is at least partially delimited by the first bearing support (32), this lubrication chamber (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), and - an oil supply circuit (40) for the enclosure (38), this circuit (40) comprising an oil distributor (48) integral with the housing (36) and comprising at least one oil inlet (48a) and at least one oil outlet (48b), the distributor (48) comprising a body (62) having an internal cavity (64) which is connected to said inlet (48a) and to said outlet (48b), the distributor (48) further comprising a member (60) housed in said cavity (64) and movable from a first position in which it permits fluid communication between the inlet (48a) and the outlet (48b), and a second position in which it prevents fluid communication between the inlet (48a) and the outlet (48b), the member (60) being mechanically connected to one of said shear screws (42), the distributor (48) further being configured so that the member (60) assumes its first normal operating position when the fusible screws (42) are unbroken,and that the component (60) adopts its second position when the fusible screws (42) have broken.

2. Module (30) according to claim 1, wherein the member (60) is forced into its second position by a return element (70) such as a spring.

3. Module (30) according to claim 1 or 2, wherein the member (60) forms a valve or spool of the distributor (48).

4. Module (30) according to any one of the preceding claims, wherein the component (60) has a general piston shape and comprises a cylindrical body (60a) connected to a rod (60b).

5. Module (30) according to any one of the preceding claims, wherein the member (60) is directly connected to one of the fusible screws (42) and in particular to a threaded part (42a) of this fusible screw (42).

6. Module (30) according to all claims 4 and 5, wherein one end of the rod (60b) is connected to the threaded part (42a).

7. Module (30) according to any one of the preceding claims, wherein the member (60) and the fusible screw (42) are coaxial.

8. Module (30) according to any one of the preceding claims, wherein the distributor (48), and in particular its body (62), is fixed to a flange (36a) of the housing (36).

9. 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 a flange (36a) of the housing (36).

10. 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.

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

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