CRANKCASE FOR AN AIRCRAFT TURBOMACHINE

Abstract

The invention relates to a housing (8) comprising: - an internal annular ring (19) defining an internal lubrication chamber (17) and an external annular ring (18), - an arm extending radially between the internal and external annular rings (19, 18) comprising: an internal cavity (200) comprising a first compartment (21a) opening into the lubrication chamber (17) through an oil inlet (200a) formed in the internal ring (19), and a second compartment (21b), the second compartment (21b) being separated from the lubrication chamber (17) by a cover (22) extending longitudinally into the lubrication chamber (17) from the second annular edge (19b) of the internal annular ring (19) to the oil inlet (200a), and the oil inlet (200a) is circumferentially delimited by first and second walls (23a, 23b) extending radially from the inner ferrule (19), on either side of the oil inlet (200a).Abbreviated figure: Figure 4.

Description

Title of the invention: Casing for an aircraft turbomachine Technical field of the invention

[0001] The invention relates to the field of housings for aircraft turbomachinery.

[0002] More particularly, the invention falls within the field of housings defining a lubrication chamber, for turbomachinery including a lubrication system for a speed reducer, comprising main and auxiliary lubrication circuits. Technical background

[0003] An aircraft turbomachine typically comprises, from upstream to downstream in the direction of gas flow, a movable fan rotating about a longitudinal axis, a low-pressure compressor and a high-pressure compressor, a combustion chamber, a high-pressure turbine and a low-pressure turbine and a gas exhaust nozzle.

[0004] The blower allows the intake of an airflow that splits into a primary flow and a secondary flow. The primary flow passes through a primary channel of the turbomachine while the secondary flow is directed towards a secondary channel surrounding the primary channel.

[0005] The turbomachine further comprises an inlet casing centered on the longitudinal axis and defining the inlet of the primary flow. The inlet casing comprises an annular inner ring surrounded by an annular outer ring connected by radial arms.

[0006] The primary flow is compressed downstream within the compressors. The compressed air is then mixed with a fuel and burned in the combustion chamber. The combustion gases pass through the turbines and then escape through the nozzle, the cross-section of which allows these gases to be accelerated to generate propulsion.

[0007] The low-pressure turbine rotor is connected to the low-pressure compressor rotor by a low-pressure shaft, and the high-pressure turbine rotor is connected to the high-pressure compressor rotor by a high-pressure shaft. Furthermore, the blower is driven by a blower shaft connected to the low-pressure shaft by a speed reducer, which allows the blower to be driven at a rotational speed lower than that of the low-pressure shaft. The speed reducer is typically arranged within a lubrication chamber for its lubrication. The lubrication chamber is typically located inside the inner shell.

[0008] To ensure lubrication of the speed reducer within the lubrication chamber, the turbomachine further comprises a main lubrication circuit for the reducer connected to the lubrication chamber. The main circuit includes a gearbox oil supply pump connected to a main oil reservoir. The oil supply pump is typically driven by the high-pressure shaft via an accessory drive gearbox.

[0009] During certain operating phases of the turbomachine, such as the free rotation phases of the fan (known as "windmilling") during which the fan shaft rotates, thereby driving the low-pressure shaft, the rotational speed of the high-pressure shaft is insufficient to drive the feed pump at a speed sufficient to provide the flow rate necessary for lubricating the gearbox. However, it is necessary to ensure lubrication of the gearbox even during these operating phases of the turbomachine.

[0010] In this context, the turbomachine includes an auxiliary lubrication circuit for the gearbox. The auxiliary circuit typically includes an auxiliary pump powered by an electric generator, for example, or driven by the low-pressure shaft, which allows the auxiliary pump to prime even in the event of free rotation of the blower and low rotational speed of the high-pressure shaft.

[0011] To supply the auxiliary circuit with oil, document FR-A1-3 075 875 proposes recovering the oil flowing by gravity into the bottom of the enclosure. For this purpose, one of the radial arms located at 6 o'clock has an internal cavity opening into the enclosure through an oil inlet. The arm also has a first oil outlet connected to the main circuit by a first line and a second oil outlet connected to the auxiliary circuit by a second line. The first line is connected to an oil recovery pump supplying the main reservoir, and the second line is connected to an auxiliary pump of the auxiliary circuit.

[0012] Furthermore, according to this document, a radial partition is arranged in the internal cavity and delimits an upstream compartment and a downstream compartment, the second pipe being connected to the upstream compartment and the first pipe being connected to the downstream compartment.

[0013] Thus, during phases such as the free rotation of the blower, when the feed pump is not primed, the auxiliary pump draws oil flowing by gravity into the arm located at 6 o'clock through the second pipe. The auxiliary circuit can therefore be supplied with oil to lubricate the gearbox during these phases.

[0014] Although this solution provides a volume of oil for auxiliary lubrication of the speed reducer in the event, for example, of free rotation of the blower, the volume of oil available for these operating phases can be increased. Indeed, this document shows that to maximize oil recovery, the oil inlet has a maximum axial dimension extending over the entire width The axial length of the arm is defined between its upstream and downstream edges. The combination of the oil inlet configuration and the presence of the radial wall hinders optimal oil recovery in the first line. This is because the oil flowing by gravity in the arm supplies both the upstream and downstream compartments. Therefore, the main circuit can be supplied with oil even when the auxiliary circuit does not have its maximum volume during the blower's free-rotating operation. During these phases, while gearbox lubrication is guaranteed, it can be further optimized.

[0015] There is therefore a need to provide a solution to optimize the lubrication of the speed reducer during all operating phases of the turbomachine. Summary of the invention

[0016] To this end, the invention proposes a housing for an aircraft turbomachine, the housing extending around a longitudinal axis, and comprising:

[0017] - an internal annular ferrule centered on the longitudinal axis and defining an internal later a lubrication chamber, the internal annular ferrule having first and second axially opposed annular edges,

[0018] - an external annular ferrule arranged coaxially around the annular ferrule internal,

[0019] - arms extending radially between the inner and outer annular ferrules, one arms, called 6 o'clock arms, being tubular and located at 6 o'clock, this 6 o'clock arm comprising:

[0020] an external radial end connected to the external ferrule and an internal radial end connected to the internal ferrule,

[0021] an internal cavity comprising a first compartment opening into the lubrication chamber through an oil inlet provided in the inner shell, and a second compartment,

[0022] a first oil outlet located in the second compartment,

[0023] a second oil outlet located in the first compartment, the first and second oil outlets being radially offset with respect to the radially internal end.

[0024] The housing according to the invention is remarkable in that the second compartment is separated from the lubrication chamber by a cover extending longitudinally into the lubrication chamber from the second annular edge to the oil inlet and in that the oil inlet is circumferentially delimited by first and second walls extending radially from the inner ferrule, on either side of the oil inlet.

[0025] Thanks to the lid separating the second compartment of the 6 o'clock arm from the first compartment of the 6 o'clock arm, in combination with the first and second delimiting walls At the oil inlet, the oil flows preferentially into the first compartment which is intended to be connected to an auxiliary reservoir of an auxiliary lubrication circuit.

[0026] The auxiliary reservoir is therefore supplied with oil as a priority, which ensures lubrication of the speed reducer when the auxiliary circuit is active.

[0027] Thanks to the housing of the invention, a larger volume of oil can be stored in the auxiliary reservoir to supply the auxiliary circuit. The speed reducer can therefore be optimally, reliably and efficiently lubricated during all operating phases of the turbomachine.

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

[0029] - the first and second walls extend longitudinally in the inner ferrule of the first annular edge to the second annular edge,

[0030] - the oil inlet is axially delimited by a third wall located between the first and second low walls, extending radially into the first compartment,

[0031] - the third wall extends radially to the second oil outlet,

[0032] - of the first and second chutes arranged on either side of the first and second walls and configured to convey oil from the lubrication chamber to the oil inlet,

[0033] - the first and second chutes extend over an angular sector around the axis longitudinal angle between 5° and 10°,

[0034] - the 6h arm comprises a radial partition arranged in the internal cavity and separating the first compartment of the second compartment,

[0035] - the radially external end of the arm 6h has a bottom wall in which is provided the second oil outlet, the partition extending radially towards the inside of the arm 6h from the bottom wall.

[0036] The invention also relates to a turbomachine for an aircraft, comprising a casing according to any one of the preceding characteristics.

[0037] The turbomachine may comprise one or more of the following features, taken individually or in combination with each other:

[0038] - a blower driven in rotation around the longitudinal axis by a shaft of blower,

[0039] - a low-pressure shaft connected to the blower shaft by a speed reducer mechanical components arranged within the lubrication chamber,

[0040] - a speed reducer lubrication system comprising a main circuit lubrication and an auxiliary lubrication circuit connected to the crankcase lubrication chamber, the auxiliary circuit being connected to an auxiliary reservoir, the auxiliary reservoir being located outside the outer shell of the crankcase, the first outlet one oil outlet being connected to the main circuit and the second oil outlet being connected to the auxiliary reservoir,

[0041] - the auxiliary reservoir is directly connected to the second oil outlet of the crankcase,

[0042] - the auxiliary reservoir is housed in an inter-vein compartment which is configured to separate an airflow produced by the blower into a primary flow and a secondary flow. Brief description of the figures

[0043] Other features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings in which:

[0044] [Fig. 1] is a schematic longitudinal cross-sectional representation of an aircraft turbomachine according to the invention,

[0045] [Fig.2] is a schematic longitudinal sectional representation of a speed reducer equipping the turbomachine of [Fig.1],

[0046] [Fig.3] is a schematic view of a lubrication system for the speed reducer of [Fig.2] according to an exemplary embodiment of the invention,

[0047] [Fig. 4] is a schematic perspective view of a housing according to the invention,

[0048] [Fig.5] is another schematic perspective view of the housing of [Fig.4],

[0049] [Fig.6] is a longitudinal cross-sectional view of the housing of figures 4 and 5. Detailed description of the invention

[0050] An example of an aircraft turbomachine 1 according to the invention is shown in [Fig. 1]. The turbomachine 1 extends around and along a longitudinal axis X.

[0051] In the present application, the terms "axial", "axially", "radial" and "radially" are defined with respect to the longitudinal axis X.

[0052] The terms "upstream", "downstream" are defined with respect to the direction of gas flow in the turbomachine 1 along the longitudinal axis X.

[0053] The terms "internal", "interior", "external", "outside", "externally" are defined with respect to the distance from the longitudinal axis X along a radial axis Z perpendicular to the longitudinal axis X.

[0054] The turbomachine 1 comprises, from upstream to downstream, a blower 2, at least one compressor such as a low-pressure compressor 3 and a high-pressure compressor 4, a combustion chamber 5, at least one turbine such as a high-pressure turbine 6 and a low-pressure turbine 7, and a nozzle for exhausting the gases.

[0055] The blower 2 allows the aspiration of an air flow F which divides into a primary flow Fl and a secondary flow F2. The primary flow Fl passes through a primary vein la of the turbomachine 1 while the secondary flow F2 is directed towards a secondary vein 1b surrounding the primary vein la.

[0056] The primary flow Fl is compressed within the low pressure compressor 3 and then the high pressure compressor 4. The compressed air is then mixed with a fuel and burned within the combustion chamber 5. The gases formed by the combustion pass through the high pressure turbine 6 and low pressure turbine 7. The gases finally escape through the nozzle whose cross-section allows the acceleration of these gases to generate propulsion.

[0057] The blower 2 is mobile in rotation around the longitudinal axis X. The blower 2 comprises blades 2a regularly distributed around a disk centered on the longitudinal axis X.

[0058] The fan 2 is, for example, shrouded. The turbomachine 1 then comprises an annular nacelle 2b centered on the longitudinal axis X surrounding the fan 2. The nacelle 2b is, for example, supported by a fan housing (not shown).

[0059] Furthermore, the turbomachine 1 includes a housing 8. The housing 8 is, for example, an inlet housing. The housing 8 is, for example, arranged inside the nacelle 2b. The housing 8 is, for example, arranged axially between the fan 2 and the low-pressure compressor 3. The housing 8 forms an inlet nozzle for the primary flow 1a. The housing 8 includes an annular outer shell 18 and an annular inner shell 19 arranged within the outer shell 18. The outer and inner shells 18, 19 are centered on the longitudinal axis X and connected by radial arms. Each of the external and internal ferrules 18, 19 has a first annular edge 18a, 19a, in particular an upstream annular edge 18a, 19a and a second annular edge 18b, 19b, in particular a downstream annular edge 18b, 19b. The first and second annular edges 18a, 19a, 18b, 19b are axially opposed.

[0060] The primary vein is delimited downstream of the inlet spout by an internal casing 110 arranged downstream of the external ferrule 18 and the internal ferrule 19.

[0061] The secondary vein 1b is further delimited radially by the gondola 2b and an inter-vein housing 180 arranged radially between the gondola 2b and the housing 8.

[0062] In addition, an interveinal compartment is arranged radially between the secondary vein 1b and the primary vein 1a. The interveinal compartment has a first zone ZI delimited internally by the external ferrule 18 and externally by the interveinal casing 180. The interveinal compartment includes a second zone Z2 downstream of the first zone ZI.

[0063] In the particular example of [Fig.1], the rotor of the low-pressure turbine 7 is connected to the rotor of the low-pressure compressor 3 by a low-pressure shaft 10. The rotor of the high-pressure turbine 6 is connected to the rotor of the high-pressure compressor 4 by a high-pressure shaft 9. The low-pressure shaft 10 is arranged coaxially inside the high-pressure shaft 9 and extends along the longitudinal axis X.

[0064] The low-pressure shaft 10 is guided in rotation by bearings. An intermediate bearing 10a is arranged radially between the low-pressure shaft 10 and a first bearing support 10b connected, for example, to the inner shell 19. The intermediate bearing 10a is, for example, a ball bearing.

[0065] The blower 2 is driven in rotation by a blower shaft 11. The blower shaft 11 is connected to the disk for its rotational drive. The blower shaft 11 is supported by a downstream bearing 11a arranged radially between the blower shaft 11 and a second bearing support 11b connected to the inner ferrule 19. The downstream bearing 11a is, for example, a ball bearing. It is arranged upstream of the intermediate bearing 10a. The downstream bearing 11a is arranged on a downstream end of the blower shaft 11.

[0066] The blower shaft 11 is also connected to the low-pressure shaft 10 via a speed reducer 12. The speed reducer 12 is of the mechanical type.

[0067] As more clearly seen in [Fig.2], the speed reducer 12 comprises a solar 13, a ring 14, at least one satellite 15 which meshes with the ring 14 and the solar 13, and a satellite carrier 16.

[0068] The solar element 13 is rotationally coupled with the low-pressure shaft 10. It forms the input of the reducer 12.

[0069] The speed reducer 12 advantageously comprises a plurality of satellites 15. Each satellite 15 has a central axis X' parallel to the longitudinal axis X.

[0070] The ring 14 is annular and is arranged around the longitudinal axis X. As shown in [Fig. 1], the ring 14 is rotationally coupled with the blower shaft 11. The ring 14 includes, for example, a mounting flange 14a connected to the blower shaft 11, for example, by means of mounting rods 14b, such as screws. The ring 14 forms the output of the reducer 12.

[0071] The satellite carrier 16 is fixed in rotation about the longitudinal axis X. The satellite carrier 16 is connected to a fixed structure of the turbomachine 1. According to the example of [Fig.2], the satellite carrier 16 is connected to the inner shell 19, for example by means of a flexible support 11c.

[0072] The speed reducer 12 is composed of gears and bearings that require lubrication. For this purpose, lubricating oil is sprayed onto the speed reducer 12. In order to protect the other components of the turbomachine 1 from this oil, the speed reducer 12 is arranged in an annular lubrication chamber 17. The lubrication chamber 17 is, for example, an upstream chamber. The lubrication chamber 17 is located inside the inner shell 19. The lubrication chamber 17 is thus defined by the inner shell 19. It may include the upstream bearing 1a and the intermediate bearing 10a.

[0073] The lubrication chamber 17 has a chamber bottom F. The chamber bottom F is located at the lowest point of the lubrication chamber 17, i.e. of the inner shell 19. The lubricating oil flows by gravity into the bottom of the chamber F.

[0074] With reference to [Fig. 3], among the radial arms extending radially between the outer ferrule 18 and the inner ferrule 19, a tubular arm 20 is located at 6 o'clock (six o'clock) by analogy to the corresponding position on the face of a clock. For simplicity, in the remainder of this description, this 6 o'clock arm will be referred to as the "arm".

[0075] The arm 20 comprises a radially internal end 20a connected to the internal ferrule 19, in particular connected to the lubrication chamber 17, specifically to the chamber bottom F. The radially internal end 20a is, for example, open. The arm 20 further comprises a radially external end 20b connected to the external ferrule 18 and opposite the radially internal end 20a. The radially external end 20b has, for example, a bottom wall 20b' preferably formed by the external ferrule 18.

[0076] The arm 20 also has a first face and a second face that are opposite and extend radially between the radially external end 20b and the radially internal end 20a. The first and second faces advantageously extend axially between the annular edges of the external and internal ferrules 18, 19. The first and second faces meet at a first edge 201, in particular at an upstream edge 201 and a second edge 202, in particular a downstream edge 202. The upstream and downstream edges 201, 202 are axially connected to each other at their external end by the bottom wall 20b'.

[0077] The arm 20 further comprises an internal cavity 200 including a first compartment 21a, in particular an upstream compartment 21a, and a second compartment 21b, in particular a downstream compartment 21b. According to a preferred embodiment of the invention, the arm 20 includes a radial partition 21 arranged in the internal cavity 200 and separating the first and second compartments 20a, 20b. The radial partition 21 extends, for example, radially inward from the bottom wall 20b'. The first and second compartments 21a, 21b each have a predetermined volume.

[0078] The first compartment 21a opens into the lubrication chamber 17 through an oil inlet 200a. The lubricating oil can therefore flow by gravity out of the lubrication chamber 17 into the arm 20. The oil inlet 200a is provided, for example, in the inner ferrule 19 and opens into the first compartment 21a.

[0079] With reference to Figures 4 and 5, according to the invention, the oil inlet 200a is circumferentially delimited around the longitudinal axis X by first and second walls 23a, 23b. The first and second walls 23a, 23b are arranged on either side of the oil inlet 200a. The first and second walls 23a, 23b are located in the inner ferrule 19 and extend radially from the inner ferrule 19. They extend radially inwards from the inner ferrule 19. They form, for example, a only piece with the internal ferrule 19. The internal ferrule 19 and the first and second walls 23a, 23b came from material.

[0080] Preferably, the first and second walls 23a, 23b extend radially along the extension of the arm 20, that is, along the extension of the first and second faces of the arm 20. The first and second walls 23a, 23b extend longitudinally within the inner ferrule 19. They extend between the first annular edge 19a and the second annular edge 19b, preferably from the first annular edge 19a to the second annular edge 19b of the inner ferrule 19. The first and second walls 23a, 23b are parallel to each other. The first and second walls 23a, 23b have a height hl such that it is measured along the radial axis Z, which is preferably identical.

[0081] With reference to Figures 4 to 6, according to a preferred embodiment of the invention, the oil inlet 200a is axially delimited by a third wall 23c. The third wall 23c is arranged between the first and second walls 23a, 23b. It extends radially inwards from the inner ferrule 19 and perpendicular to the first and second walls 23a, 23b. The third wall 23c extends radially into the first compartment 21a. It is arranged upstream of the partition 21.

[0082] According to the invention, the second compartment 21b is separated from the lubrication chamber 17 by a cover 22. The cover 22 thus makes it possible to close the second compartment 21b at its inner end so that the oil flows exclusively into the first compartment 21a.

[0083] The cover 22 extends longitudinally within the lubrication chamber 17 from the second annular edge 19b to the oil inlet 200a. The cover 22 thus has an upstream end 22a located on the side of the oil inlet 200a and a downstream end 22b axially opposite it. Therefore, the third wall 23c is axially offset downstream relative to the upstream end 22a of the cover 22. This further limits the risk of oil flowing from the lubrication chamber 17 into the second compartment 21b.

[0084] According to a preferred embodiment of the invention, the cover 22 is integral with the first and second walls 23a, 23b. The cover 22 is fixed to the first and second walls 23a, 23b by bolting. For example, lugs 23c project from the first and second walls 23a, 23b. The lugs 23c of the first wall 23a are oriented towards the lugs 23c of the second wall 23b. The lugs 23c of the first and second walls 23a, 23b are, for example, arranged in a staggered pattern. The cover 22 is connected to the lugs 23c by bolts 22c.

[0085] Advantageously, the cover 22 has a circumferential width equal to the circumferential width of the arm 20. The cover 22 extends circumferentially between the first and second faces of the arm 22. This prevents oil from flows by gravity into the second compartment 21b.

[0086] According to a preferred embodiment of the invention, the housing 8 further comprises first and second channels 32a, 32b arranged on either side of the first and second walls 23a, 23b. The first and second channels 32a, 32b are configured to convey oil from the lubrication chamber 17 to the oil inlet 200a and thus promote oil flow into the first compartment 21a. The first and second channels 32a, 32b extend from the first and second walls 23a, 23b, opposite the second annular edge 19b of the inner shell 19. They are thus located on the side of the oil inlet 200a. The first and second chutes 32a, 32b extend around the longitudinal axis X over an angular sector between 5° and 10°.

[0087] With reference to [Fig.3], the arm 20 further comprises a first oil outlet 20c and a second oil outlet 20d radially opposed to the oil inlet 200a. They are, for example, provided in the bottom wall 20b' and / or the downstream edge 202. The first outlet 20c is, for example, provided in the downstream edge 202 and the second outlet 20d is, for example, provided in the bottom wall 20b'.

[0088] The first exit 20c is located in the second compartment 21b, therefore the downstream compartment 21b, and the second exit 20d is located in the first compartment 21a, therefore the upstream compartment 21a. Preferably, the third wall 23c extends to the second exit 20d.

[0089] In order to ensure the lubrication of the speed reducer 12 in the lubrication chamber 17, the turbomachine 1 includes a lubrication system for the speed reducer 12.

[0090] The lubrication system includes a main lubrication circuit 24, an auxiliary lubrication circuit 25, the main and auxiliary circuits 24, 25 being connected to the lubrication chamber 17. The lubrication system 23 may further include a selective projection device 26 of the lubricating oil into the lubrication chamber 17, this selective projection device 26 being connected to the main circuit 24 and the auxiliary circuit 25.

[0091] The main circuit 24 typically includes a supply circuit 240 connecting a main reservoir 240b to the lubrication chamber 17. The supply circuit 240 includes a supply pump 240a mounted between the main reservoir 240b and the lubrication chamber 17, in particular between the main reservoir 240b and the selective spray device 26. The supply pump 240a is, for example, mechanically driven by the high-pressure shaft 9. Advantageously, the supply pump 240a is connected to the high-pressure shaft 9 via an accessory gearbox (AGB). The accessory gearbox is, for example, housed in the inter-vein compartment. Thus, when the high-pressure shaft 9 is rotated, it primes the pump supply 240a which draws oil from the main reservoir 240b and supplies oil to the selective spraying device 26. The supply circuit 240 may further include at least one air / oil exchanger 240c arranged for example between the selective spraying device 26 and the supply pump 240a.

[0092] The main circuit 24 further includes a return circuit 241 connecting the main reservoir 240b to the second compartment 21b of the arm 20. The return circuit 241 includes a recovery pump 241a which is advantageously arranged in the inter-vein compartment. The recovery pump 241a is connected to the main reservoir 240b and to the first outlet 20c of the arm 20. In particular, the recovery pump 241a has an inlet hydraulic line 242a connected to the first outlet 20c and an outlet hydraulic line 242b which is connected to the main reservoir 240b.

[0093] In some cases, the high-pressure shaft 9 is not driven to rotate or is driven at a rotational speed insufficient to drive the feed pump 240a. For example, when the blower 2 is in free rotation (or self-rotating, also known as "windmilling"), or during the start-up or shutdown phases of the turbomachine 1, the feed pump 240a is not primed and is no longer able to supply oil to the selective spraying device 26. The speed reducer 12 is then no longer lubricated by the main circuit 24. Lubrication of the speed reducer 12 is ensured in such a case by the auxiliary circuit 25.

[0094] The auxiliary circuit 25 is a closed lubrication circuit for the lubrication chamber 17. It includes an auxiliary pump 28 connected to an auxiliary reservoir 31 and to the lubrication chamber 17, in particular to the selective projection device 26.

[0095] The auxiliary reservoir 31 is located outside the outer shell 18. Preferably, the auxiliary reservoir 31 is arranged in the inter-flow compartment, for example in the first zone ZI. Since the auxiliary reservoir 31 is located outside the primary flow, it can have a large internal volume without impacting the aerodynamic performance of the turbomachine 1. A large volume of oil can thus be stored.

[0096] The auxiliary reservoir 31 is connected to the second oil outlet 20d of the arm 20. Thus, the auxiliary reservoir 31 and the first compartment 21a are connected. The oil flowing by gravity into the first compartment 21a is stored in the auxiliary reservoir 31.

[0097] Thanks to the cover 22 of the invention, the auxiliary reservoir 31 is filled first. The risks of underfilling the auxiliary reservoir 31 with oil are limited. This ensures optimal and reliable lubrication of the speed reducer 12 regardless of the operating phases of the turbomachine 1.

[0098] Preferably, the auxiliary tank 31 is directly connected to the second 20d oil outlet from arm 20.

[0099] The auxiliary pump 28 is driven, for example, by an electric motor 29. The auxiliary pump 28 and the electric motor 29 are, for example, arranged in the inter-vein compartment 1. The electric motor 29 is supplied with electrical energy by an electric generator (not shown), for example, located in the lubrication chamber 17. The electric generator provides electrical energy to the electric motor 29 from mechanical energy. The electric generator, for example, draws mechanical energy from the blower shaft 11. For example, the electric generator is connected to the blower shaft 11 via gears 30.

[0100] The electric motor is, for example, controlled by a control unit 290. The control unit 290 allows the speed of the auxiliary pump 28 to be modulated via the electric motor. The control unit is, for example, a FADEC (for "Full Automatic Digital Engine Control").

[0101] According to another example, the auxiliary pump 28 is driven by the low-pressure shaft 10.

[0102] The selective projection device 26 includes, for example, a selection member 27' and at least one nozzle 27 which is arranged in the lubrication chamber 17. The selection member 27' is, for example, a selection valve connected to the main and auxiliary circuits 24, 25.

[0103] The nozzle 27 allows the lubricating oil to be projected into the lubrication chamber 17. The selective projection device 26 advantageously comprises two nozzles 27, a first nozzle projecting the lubricating oil onto the speed reducer 12 and a second nozzle projecting the oil onto the gears 30. The nozzles are connected to the selection member 27' and are supplied with lubricating oil by one of the circuits 24, 25 depending on the position of the selection valve.

[0104] The operation of the main and auxiliary circuits 24, 25 will now be described.

[0105] In a first phase of operation, the turbomachine 1 is stopped. The main and auxiliary circuits 24, 25 are therefore stopped. In this first phase, the auxiliary tank 31 contains oil remaining from a previous flight.

[0106] In a first phase of nominal operation of the turbomachine 1, the auxiliary circuit 25 is inactive, i.e., the auxiliary pump 28 is inactive. The main circuit 24 is active, i.e., the feed pump 240a is active and draws oil from the main reservoir 240b. The oil is conveyed to the lubrication chamber 17 via the main circuit 24. In this first phase, the lubricating oil flows by gravity into the bottom of the chamber F and into the arm 20. Thanks to the cover 22, the oil flows preferentially into the first compartment. compartment 21a. This oil is stored in the auxiliary tank 31. In this phase, the volume of oil in the first compartment 21a is less than the maximum volume of the first compartment 21a. The recovery pump 241a is also active, for example.

[0107] In a second phase of nominal operation of the turbomachine 1, the main circuit 24 is still active, but the volume of oil in the auxiliary reservoir 31 is greater than the maximum volume of the auxiliary reservoir 31 and the maximum volume of the first compartment 21a. The oil is transferred, for example, by overflow into the second compartment 21b. The recovery pump 241a in this second phase then draws oil from the second compartment 21b and allows the oil to circulate in the return circuit 241 of the main circuit 24 to supply oil to the main reservoir 240b.

[0108] In a third operating phase of the turbomachine 1, for example, if the fan 2 is rotating freely and the high-pressure shaft 10 is stopped or its rotation speed is insufficient, the pressure in the main circuit 24 decreases such that the selector 27' is supplied by the auxiliary circuit 25, in which the oil pressure is higher. This is because the supply pump 240a is then unprimed or provides an insufficient flow rate, while the auxiliary circuit 25 is active. The auxiliary pump 28 draws oil from the auxiliary reservoir 31 and circulates it through the auxiliary circuit 25 to lubricate the gearbox 12 in the lubrication chamber 17.

[0109] Thanks to the invention, it is possible to increase the volume of the auxiliary tank 31 without impacting the aerodynamic performance and the size of the turbomachine 1.

[0110] Thanks to the invention, it is possible to guarantee an optimal volume of oil in the auxiliary reservoir 31 for the lubrication of the speed reducer 12 in the lubrication chamber 17 in the event of a stoppage of the supply pump 240a of the main circuit 24, for example in the event of free rotation of the blower 2.

Claims

Demands

1. Casing (8) for an aircraft turbomachine (1), the casing (8) extending about a longitudinal axis (X), and comprising: - an internal annular ring (19) centered on the longitudinal axis (X) and internally defining a lubrication chamber (17), the internal annular ring (19) having first and second annular edges (19a, 19b) axially opposed, - an external annular ring (18) arranged coaxially around the internal annular ring (19), - arms extending radially between the internal and external annular rings (19, 18), one of the arms, called arm 6h (20), being tubular and located at 6h, this arm 6h (20) comprising: a radially external end (20b) connected to the external ring (18) and a radially internal end (20a) connected to the internal ring (19),an internal cavity (200) comprising a first compartment (21a) opening into the lubrication chamber (17) through an oil inlet (200a) formed in the internal ferrule (19), and a second compartment (21b), a first oil outlet (20c) located in the second compartment (21b), a second oil outlet (20d) located in the first compartment (21a), the first and second oil outlets (20c, 20d) being radially offset with respect to the radially internal end (20a), characterized in that the second compartment (21b) is separated from the lubrication chamber (17) by a cover (22) extending longitudinally into the lubrication chamber (17) from the second annular edge (19b) to the oil inlet (200a) and in that the oil inlet (200a) is delimited circumferentially by first and second walls (23a, 23b) extending radially from the inner ferrule (19), on either side of the oil inlet (200a).

2. Carter according to the preceding claim, characterized in that the first and second walls (23a, 23b) extend longitudinally in the internal ferrule (19) from the first annular edge (19a) to the second annular edge (19b).

3. A housing according to any one of the preceding claims, characterized in that the oil inlet (200a) is axially delimited by a third wall (23c) located between the first and second walls (23a, 23b) and extending radially into the first compartment (21a).

4. Carter according to the preceding claim, characterized in that the third wall (23c) extends radially to the second oil outlet (20d).

5. Housing according to any one of the preceding claims, characterized in that it comprises first and second chutes (32a, 32b) arranged on either side of the first and second walls (23a, 23b) and configured to convey oil from the lubrication chamber (17) to the oil inlet (200a).

6. Housing according to the preceding claim, characterized in that the first and second chutes (32a, 32b) extend over an angular sector around the longitudinal axis (X) between 5° and 10°.

7. Carter according to any one of the preceding claims, characterized in that the arm 6h (20) comprises a radial partition (21) arranged in the internal cavity (200) and separating the first compartment (21a) from the second compartment (21b).

8. Housing according to the preceding claim, characterized in that the radially external end (20b) of the 6h arm (20) has a bottom wall (20b') in which the second oil outlet (20d) is provided, the partition (21) extending radially towards the inside of the 6h arm (20) from the bottom wall (20b').

9. Turbomachine (1) for an aircraft, characterized in that it comprises a casing (8) according to any one of the preceding claims.

10. Turbomachine according to the preceding claim, characterized in that it further comprises: - a fan (2) driven in rotation about the longitudinal axis (X) by a fan shaft (11), - a low-pressure shaft (10) connected to the fan shaft by a mechanical speed reducer (12) arranged in the lubrication chamber (17), - a lubrication system for the speed reducer (12) comprising a main lubrication circuit (24) and an auxiliary lubrication circuit (25) connected to the lubrication chamber (17) of said housing (8), the auxiliary circuit (25) being connected to an auxiliary reservoir (31), the auxiliary reservoir (31) being located outside the outer shell (18) of said housing (8), the first oil outlet (20c) being connected to the main circuit (24) and the second oil outlet (20d) being connected to the auxiliary reservoir (31).

11. Turbomachine according to the preceding claim, characterized in that the auxiliary tank (31) is directly connected to the second oil outlet (20d) of said crankcase (8).

12. Turbomachine according to claim 10 or 11, characterized in that the auxiliary tank (31) is housed in an inter-vein compartment (le) which is configured to separate an airflow (F) produced by the blower (2) into a primary flow (F1) and a secondary flow (F2).

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