Tank tank for a turbomachine with negative g compatible

Abstract

The invention relates to an oil tank (40) for an aircraft turbomachine, comprising: a main enclosure (54) capable of containing oil; an oil inlet (66) for oil mixed with air; an oil outlet (72); wherein the oil tank further comprises: an auxiliary enclosure (56) arranged within the main enclosure, the auxiliary enclosure comprising an enclosure wall (60) and two end walls (61, 63), the two end walls being adjacent to the enclosure wall, at least one of the two end walls comprising at least one oil passage (62) leading to the interior of the main enclosure, at least one auxiliary inlet (67), the invention is characterized in that the main enclosure comprises at least one secondary inlet opening tangentially to the enclosure wall and passing through the main enclosure, a secondary outlet (74) tangential to a larger diameter section (60.1) of the enclosure wall, said secondary outlet passing through the main enclosure to be connected to a secondary circuit.

Description

Technical Field

[0001] The present invention relates to the field of turbine cans and more particularly to the field of oil cans for lubricating turbine components, including in particular unducted variable pitch propellers and / or variable pitch rectifiers. Background Art

[0002] An aircraft turbomachine comprising at least one unducted propeller is called an "open rotor" or "unducted fan". In this category of turbomachines, there are turbomachines with two unducted counter-rotating propellers, called unducted dual fans (UDF), or turbomachines with a single unducted propeller and a rectifier comprising a plurality of stator blades (USF).

[0003] These turbines differ in that they use a propeller outside the nacelle (unducted) rather than an internal fan.

[0004] The propeller or propellers forming the propulsion means generally include a system for actuating the pitch of the blades of the propeller or propellers (also known as a variable pitch system). Such a system enables the propeller blades to be oriented as required by the flight phase of the aircraft (take-off, cruise, landing, etc.) so as to ensure thrust management in all flight situations of the turbomachine.

[0005] In the case of a turbine with a single unducted propeller and a rectifier, the rectifier may also include a variable pitch system to improve the performance of the turbine. Published patent document FR 3 107 319 A1 discloses an example of such a turbine.

[0006] Variable pitch systems may require a continuous supply of oil to enable actuation of the blade pitch and management of the engine thrust in all flight conditions (normal and extreme) of the engine. In the prior art, these systems are supplied by a main lubrication circuit to ensure the supply of oil to the various components of the engine (bearings, reducers, etc.) to provide lubrication and / or cooling functions. This circuit is supplied with oil by the main tank of the turbine, which comprises, among other things, an oil inlet located in the upper part and an oil outlet located in the lower part, which enables the supply of oil during flight attitudes in gravity or with a positive load factor (positive G).

[0007] Although such oil tanks are completely satisfactory when the aircraft is flying in positive G flight conditions, on the other hand, these tanks no longer fully ensure the oil supply to the pitch actuation system when the aircraft is in a flight phase with zero or negative load factor (zero G or negative G), i.e. when the aircraft is maneuvering or encountering upward gusts.

[0008] In practice, a zero-gravity or negative-gravity flight phase is a temporary flight phase (often lasting less than 30 seconds for a civilian aircraft) during which the aircraft is subjected to negative accelerations (for example when the aircraft undergoes a sudden loss of altitude).

[0009] For this reason, the oil contained in the main tank thus surges out and is no longer located near the outlet in the lower part, which interrupts the oil supply and causes air to flow to one or more variable pitch circuits, with harmful consequences for the operation of the turbine, which may lead to a loss of control of the aircraft.

[0010] It is possible to use tanks such as those used in combat aircraft, where negative G flight phases are frequent and necessary. However, these tanks are pressurized, which means a significant excess weight and high additional costs, which is incompatible with a turbine including at least one unducted propeller.

[0011] Furthermore, a known solution to avoid compromising the propeller pitch actuation circuit is to ensure the oil supply in the case of negative G by a system other than the main oil tank of the turbine. However, this solution involves significant volume and mass inside the turbine and complex management of the oil delivery to the variable pitch system.

[0012] The published patent document FR 3 010 133 A1 discloses a tank comprising an inclined partition provided at its end with through holes for continuous supply of the turbine. However, the solution proposed in this document still leaves room for improvement, so that, for example, in the case of negative G flight, a greater volume of oil can be available to supply the components of the turbine, without obstructing said volume when returning to positive G. Summary of the invention

[0013] Technical issues

[0014] The present invention aims to overcome at least one of the above-mentioned disadvantages of the prior art. More specifically, the present invention aims to propose a tank whose design enables the aircraft to perform temporary flight phases under negative gravity in total safety, without increasing the weight and cost of the tank.

[0015] Technical Solution

[0016] The present invention relates to an oil tank for an aircraft turbine, the oil tank comprising:

[0017] - a main capsule, capable of containing oil;

[0018] - an oil inlet for oil mixed with air, the oil inlet being arranged on the main casing;

[0019] - an oil outlet, which is arranged on the main casing;

[0020] The oil tanks also include:

[0021] - an auxiliary enclosure arranged inside the main enclosure, the auxiliary enclosure comprising an enclosure wall and two end walls adjacent to the enclosure wall, at least one of the two end walls comprising at least one oil passage leading to the interior of the main enclosure,

[0022] - at least one auxiliary inlet opening tangentially to the enclosure wall and passing through the main enclosure for connection to an auxiliary circuit;

[0023] - An auxiliary outlet, tangential to the larger diameter section of the enclosure wall, which passes through the main enclosure to be connected to the auxiliary circuit.

[0024] The oil flows from at least one auxiliary inlet to the auxiliary outlet so that the oil can flow in a spiral path and is thus subjected to centrifugal force to stabilize the flow. This flow is particularly stable at the auxiliary outlet so that the auxiliary outlet is continuously supplied with oil.

[0025] According to an advantageous embodiment of the invention, the enclosing wall is formed integrally with the main enclosure and the enclosing wall preferably comprises a conical shape.

[0026] According to an advantageous embodiment of the invention, at least one auxiliary inlet opens tangentially to the smaller diameter section of the enclosing wall.

[0027] According to an advantageous embodiment of the invention, at least one oil passage is centrally located on the corresponding end wall.

[0028] According to an advantageous embodiment of the invention, at least one oil passage comprises a channel extending axially from the corresponding end wall within the auxiliary enclosure.

[0029] According to an advantageous embodiment of the invention, the at least one channel extends over at least 30% or 20% of the total axial extent of the auxiliary enclosure.

[0030] According to an advantageous embodiment of the invention, at least one auxiliary inlet is located close to one of the two end walls.

[0031] According to an advantageous embodiment of the invention, the auxiliary outlet is close to one of the two end walls.

[0032] Preferably, the expression "close to" means that at least one auxiliary inlet and / or auxiliary outlet is located at any position of a quarter of the enclosing wall adjacent to one of the two end walls (along the main axis), that is, at least one auxiliary inlet and / or auxiliary outlet can be attached to one of the two end walls, or be at most 25% away from one of the two end walls.

[0033] According to an advantageous embodiment of the invention, the enclosure wall has a cone angle between 0° and 50°.

[0034] According to an advantageous embodiment of the invention, the enclosing wall comprises a single tapered portion.

[0035] According to an advantageous embodiment of the invention, the enclosure wall comprises two opposing tapered portions, the auxiliary outlet being located at the boundary between the two tapered portions.

[0036] According to an advantageous embodiment of the invention, the at least one auxiliary inlet comprises an auxiliary inlet at each of the two axial ends of the enclosing wall.

[0037] According to an advantageous embodiment of the invention, at least 80% of the volume of the auxiliary enclosure is located in the lower half of the main enclosure when the tank is oriented in the normal installation position.

[0038] According to an advantageous embodiment of the invention, the enclosure wall has a main axis which is coaxial with the passage or inclined at an angle of less than 45° relative to the passage.

[0039] Preferably, the normal installation position of the tank corresponds to a position in which the primary enclosure is located above the auxiliary enclosure in the direction of gravity (force perpendicular to the horizontal and downward). To this end, the primary enclosure, the auxiliary enclosure and the passage may be inclined when installed on the turbine, or may have a specific shape. For example, the primary enclosure is preferably substantially cylindrical, but may have a substantially rectangular and / or curved shape.

[0040] The invention also relates to a hydraulic system for an aircraft turbine, the hydraulic system comprising:

[0041] - Oil tanks;

[0042] - a lubrication circuit of the turbine, the lubrication circuit being hydraulically connected to the oil tank;

[0043] - a hydraulic control circuit of at least one hydraulic actuator, the hydraulic control circuit being hydraulically connected to an oil tank; wherein the oil tank is an oil tank according to the invention, the lubrication circuit being hydraulically connected to an inlet for oil mixed with air and to an oil outlet, the hydraulic control circuit being hydraulically connected to at least one auxiliary inlet and an auxiliary outlet.

[0044] The invention also relates to a turbine, comprising:

[0045] - an unducted propeller which propels the incoming air flow and comprises variable pitch blades actuated by at least one hydraulic actuator;

[0046] a hydraulic system capable of ensuring lubrication of the turbine and of controlling at least one hydraulic actuator;

[0047] The hydraulic system is a hydraulic system according to the present invention.

[0048] The invention also relates to a turbine, comprising:

[0049] - an unducted propeller which pushes the incoming air flow, said propeller comprising a variable pitch system for actuating the pitch of the propeller blades;

[0050] - an oil tank, the oil tank being used to lubricate the components of the turbine; wherein the tank comprises:

[0051] - a main capsule, capable of containing oil;

[0052] - an inlet for oil mixed with air, the inlet being arranged on the main casing;

[0053] - an oil outlet, which is arranged on the main casing;

[0054] - an auxiliary enclosure arranged inside the main enclosure, the auxiliary enclosure comprising an enclosure wall and two end walls adjacent to the enclosure wall, at least one of the two end walls comprising at least one oil passage leading to the interior of the main enclosure,

[0055] - at least one auxiliary inlet opening tangentially to the smaller diameter section of the enclosure wall and passing through the main enclosure for connection to an auxiliary circuit;

[0056] - An auxiliary outlet, tangential to the larger diameter section of the enclosure wall, which passes through the main enclosure to be connected to the auxiliary circuit.

[0057] According to an advantageous embodiment of the invention, the variable pitch system is a first variable pitch system, the turbine further comprises a rectifier comprising a plurality of stator blades extending from a stationary housing, the rectifier comprising a second variable pitch system, and the auxiliary outlet is hydraulically connected to a second closed circuit comprising components of the first system and / or the second variable pitch system of the turbine.

[0058] Advantages of the invention

[0059] The invention is particularly advantageous in that it makes it possible to guarantee the supply of oil to the various components of the turbomachine, in particular to one or more control systems including at least one hydraulic actuator, in this case one or more variable pitch systems, while ensuring an uninterrupted supply of oil to the one or more variable pitch systems without any air during the flight phases in zero and negative gravity. Thus, the hydraulic control of the propeller pitch actuation system of the turbomachine can remain operational during all flight phases of the aircraft.

[0060] Advantageously, the simplicity of the structure of the oil tank of the invention enables the oil tank to ensure reliable operation. In addition, the tank is compact, which enables the overall size and mass of the turbine to be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] [ Figure 1 ] is a schematic diagram of a longitudinal section of an aircraft turbine according to the invention;

[0062] [ Figure 2 ] shows Figure 1 Schematic diagram of the hydraulic system of the turbine;

[0063] [ Figure 3 ] shows a cross-sectional view of a tank according to a first embodiment of the invention during a flight phase of an aircraft in negative gravity;

[0064] [ Figure 4 ] shows Figure 3 A cross-sectional view of an alternative embodiment of an oil tank;

[0065] [ Figure 5 ] shows Figure 3 A cross-sectional view of a variation of the auxiliary sub-enclosure of the tank;

[0066] [ Figure 6 ]yes Figure 3 A top view of the enclosure wall of the oil tank;

[0067] [ Figure 7 ] shows a cross-sectional view of an oil tank according to a second embodiment of the present invention during a flight phase when the aircraft is in a negative gravity state. DETAILED DESCRIPTION

[0068] The accompanying drawings schematically illustrate components and are not drawn to scale. In particular, some dimensions are exaggerated to facilitate reading of the drawings.

[0069] Figure 1A longitudinal cross-sectional view of an aircraft turbine according to the invention is schematically shown. The aircraft turbine is a so-called open rotor or unducted fan turbine, in particular an unducted single fan (USF) turbine.

[0070] In the following description, the terms "inner" and "outer" refer to the positioning relative to the axis of rotation of the turbomachine and here along the longitudinal axis X (even in Figure 1 The terms "radial", "inner" and "outer" are defined relative to a radial direction perpendicular to the longitudinal axis X. Upstream and downstream refer to the flow direction of the flow in the turbine. Furthermore, elements shown in the figures that are identical or substantially identical and / or have the same function are denoted by the same reference numerals.

[0071] The turbomachine 2 generally comprises, from upstream to downstream, a first compression stage, known as the low-pressure compressor 4 , a second compression stage, known as the high-pressure compressor 6 , a combustion chamber 8 , a subsequent high-pressure turbine 9 and a low-pressure turbine 10 .

[0072] The turbomachine 2 comprises a propeller 14 arranged upstream of a separation nozzle 16 carried by an outer casing 24 and capable of dividing the air flow F into a secondary flow F2 and a main flow F1 which circulates in a main channel 18 and passes through the various aforementioned stages of the turbomachine 2 .

[0073] The main flow channel 18 is radially delimited by a radial inner wall 20 and a radial outer wall 22. The radial inner wall 20 is carried by the inner casing 12. The radial outer wall 22 is carried by the outer casing 24. The main air flow F1 enters the main flow channel 18 through the annular air inlet 17 and is discharged through a main nozzle 19 arranged downstream of the main flow channel 18. The main flow F1 can be accelerated by the main nozzle 19 to generate the reverse thrust required for the flight of the aircraft.

[0074] The turbine comprises a rotating casing 26 centred on and rotating about a longitudinal axis X. The rotating casing 26 carries the crowns of movable blades 28 forming the propeller 14. The rotating casing 26 is mounted movably relative to the inner casing 12 carrying it.

[0075] The air flow F entering the turbine passes through the blades 28 of the propeller 14 to form a secondary air flow F2. The secondary air flow circulates around the outer casing 24. Each blade 28 of the propeller 14 comprises a root 30 and an aerodynamic part extending radially outwards from the root 30, the root comprising a pivot. In practice, the root 30 is mounted to pivot about an axis A (perpendicular to X), thereby enabling the blades 28 of the propeller 14 to pivot. This pivoting is controlled by a first variable pitch system of the turbine 2.

[0076] The low-pressure compressor 4 and the low-pressure turbine 10 are mechanically connected via a low-pressure shaft 11, which drives a propeller 14 via a reducer 32, which compresses the air outside the outer casing 24 and provides most of the thrust of the turbine 2. The reducer 32 may be of planetary gear type.

[0077] The turbine 2 includes a straightener 34 through which a secondary flow F2 passes, the secondary flow being a portion of the air flow F that is pushed radially outward relative to the longitudinal axis X. The straightener 34 includes a plurality of stator blades 36 (or stator blades or fixed blades) (referred to as outlet guide vanes (Outlet Guide Vane, OGV)). The stator blades 36 are regularly distributed around the longitudinal axis X and extend radially in the secondary air flow F2. The stator blades 36 are carried by a fixed structure fixed to the outer casing 24. In particular, each stator blade 36 extends radially from a foot 38, which is pivotally mounted around an axis B (perpendicular to X), so that the stator blades 36 of the straightener 34 can pivot. The pivoting is controlled by a second variable pitch system of the turbine 2.

[0078] The turbine 2 further comprises an oil tank 40, 400 for lubricating and / or cooling the components of said turbine 2. To this end, the oil tank 40, 400 is the main oil tank of the turbine 2 and also enables the supply of oil to the first variable pitch system and the second variable pitch system of the turbine 2. Preferably, the tank 40, 400 is arranged in line with the outer casing 24. The structure and operation of the oil tank 40, 400 will be described in detail later in this description.

[0079] Alternatively, the oil tank 40, 400 of the present invention is capable of supplying oil to a turbine including a variable pitch system only at the rectifier (with a fixed blade propeller that does not include a variable pitch system).

[0080] Figure 2 yes Figure 1 Schematic diagram of the hydraulic system 39 of the turbine. The hydraulic system 39 comprises different closed circuits connected to the oil tank of the invention to ensure lubrication of the turbine.

[0081] Reference Figure 2 The oil tank 40 is hydraulically connected to a lubrication and cooling circuit 42 of the turbine engine, which circuit comprises a feed pump 43, an exchanger 44 and an engine enclosure 45, which ensures lubrication of the bearings, reducers and bearings and ensures air / oil sealing of the engine.

[0082] Figure 2 A tank 40 according to a first embodiment is shown, but the hydraulic system 39 may also include a tank 40 according to Figure 7 The oil tank 400 of the second embodiment is shown in FIG. These two embodiments will be described in detail below in this specification.

[0083] The lubrication circuit 42 also comprises at least one recovery pump 46 configured to recover oil from the engine enclosure 45 and direct it to the oil tank 40. The circuit 42 may correspond to a lubrication group of a turbomachine.

[0084] The oil tank 40 is also hydraulically connected to a circuit 48 for actuating the pitch of the propeller blades, which circuit is also called hydraulic control circuit 48 and is used to supply the propeller blades with a hydraulic pressure. Figure 1 The first variable pitch system of the turbine, ie the propeller 14, is supplied with oil.

[0085] The hydraulic control circuit 48 can also provide a control circuit to the first variable pitch system independently of the first variable pitch system or in combination with the first variable pitch system. Figure 1 The second variable pitch system of the turbine, ie the rectifier 34, supplies oil.

[0086] The hydraulic control circuit 48 can provide lubrication and / or cooling functions for the variable pitch system. In this regard, the circuit 48 includes a boost pump 49 that recovers oil from the lower portion of the tank 40 to direct the oil to the exchanger 50, more precisely, the boost pump 49 recovers oil contained in the auxiliary enclosure of the tank 40, which will be described in detail later in this specification.

[0087] Preferably, in addition to the lubrication and cooling functions, the hydraulic control circuit 48 is also configured to hydraulically control the variable pitch system. In this regard, the circuit 48 comprises a pitch actuation pump 51 capable of hydraulically controlling a pitch actuation system or hydraulic actuator 52, which may correspond to a first variable pitch system and / or a second variable pitch system of the turbine.

[0088] In this configuration, the stepper actuation pump 51 enables actuation of the hydraulic actuator 52, resulting in Figure 1 The feet 30 and 38 pivot.

[0089] Preferably, the hydraulic control circuit 48 comprises a bypass valve 53 making it possible to select between a cooling function or actuating the pitch of the variable pitch system.

[0090] The circuit 48 comprises at least one oil return leading to the tank 40 , 400 , which oil return is preferably accelerated by at least one of the pumps ( 49 and / or 51 ).

[0091] Advantageously, the hydraulic system 39 comprises a connection (shown in phantom) between the hydraulic control circuit 48 and the lubrication circuit 42 to collect any leakage from the propeller pitch actuation cylinders and to refill this oil from the inlet 66 into the tank 40 .

[0092] Figure 3A cross-sectional view of a tank 40 according to a first embodiment of the invention is shown during a flight phase of the aircraft in a negative G state. Here, G+ refers to positive gravity and G- refers to negative gravity.

[0093] It should be noted that the tank 40 is able to ensure a constant supply of oil during the G-flight phases, and each of the G-phases lasts from a fraction of a second to 45 seconds. Advantageously, the tank 40 can be dimensioned to ensure a constant supply of oil even in the case of more than 45 seconds.

[0094] In this regard, the oil tank 40 comprises an oil inlet 66 for oil mixed with air, the oil inlet opening to the main enclosure 54 capable of containing oil, more precisely to an oil degassing device 68, so as to be able to discharge the air 70 mixed with the oil at the oil inlet 66. The oil inlet 66 preferably comes from Figure 2 at least one recovery pump 46 .

[0095] The tank 40 comprises a secondary enclosure 56 arranged inside the primary enclosure 54 , comprising an enclosure wall 60 and having two end walls 61 , 63 adjacent to said enclosure wall 60 .

[0096] Advantageously, the arrangement of the auxiliary enclosure 56 inside the main enclosure 54 makes it possible to obtain a rapid exchange of oil flow between the auxiliary enclosure and the main enclosure.

[0097] However, in alternative solutions (such as Figure 4 As shown in FIG. 5 , the auxiliary enclosure 56 is arranged outside the main enclosure 54 to enable the tank 40' to be integrated in a particularly restricted environment of the turbine. In this regard, one or more hydraulic pipes 62' can connect the two enclosures 54 and 56. In this configuration, the one or more hydraulic pipes 62' can be flexible and / or can be merged with the channel 62.

[0098] exist Figure 4 It can be seen in FIG. 4 that the main enclosure 54 of the tank 40′ comprises an end wall 61′ corresponding to the bottom wall 61′ of the main enclosure 54. In an alternative not shown, the bottom wall may have a conical shape to facilitate the circulation of oil towards the channel 62 during the return to the G+ state.

[0099] refer to Figure 3 The enclosure wall 60 preferably corresponds to a conical wall 60, so as to enable a circular and accelerated flow of oil to be generated inside the auxiliary enclosure 56. This flow will be described in detail in this description.

[0100] Alternatively, the enclosure wall 60 may include a different shape depending on the integration and / or operation of the turbine. For example, the enclosure wall 60 may include a cylindrical shape or an elliptical shape to facilitate integration of the tank 40 in a more constrained environment.

[0101] The tank 40 also comprises an oil outlet 72 which is preferably arranged in line with the end wall 63 in the auxiliary enclosure 56 .

[0102] In this configuration, the oil inlet 66 and the oil outlet 72 form a Figure 2 The lubrication circuit 42 corresponds to the circuit.

[0103] Alternatively, the oil outlet 72 may also be located on the side wall of the main enclosure 54 .

[0104] Preferably, the enclosure wall 60 of the tank 40 is formed integrally with the main enclosure 54, which enables space saving. However, the enclosure wall 60 may be included in the auxiliary enclosure 56 at a distance from the side wall of the auxiliary enclosure 56.

[0105] exist Figure 3 It can also be seen that the two end walls 61 , 63 are formed together with the enclosing wall 60 , but these walls 61 and 63 could also be located at a distance from the enclosing wall 60 , for example by being formed together with the side walls of the main enclosure 54 .

[0106] The end wall 61 is an upper end wall 61 in the direction of gravity (perpendicular to the horizontal plane) and is arranged in the larger diameter section 60.1 of the enclosure wall 60. In parallel, the end wall 63 is a lower end wall 63 arranged in the smaller diameter section 60.2 of the enclosure wall 60.

[0107] The upper end wall 61 comprises an oil passage comprising a channel 62 extending axially (along the main axis of said channel) inside the auxiliary enclosure 56 and extending over at least 20% of the total axial extent of the auxiliary enclosure 56, up to at least 99% of said total extent, which enables the oil to reach the oil outlet 72 in the G+ state. Preferably, the channel 62 extends over 30% to 95% of the total axial extent of the auxiliary enclosure 56, and more preferably over 30% to 70% of said axial extent.

[0108] Preferably, the channel 62 is located at a central position of the upper end wall 61 and is opposite to the oil outlet 72. Advantageously, this enables the oil to quickly reach the outlet 72 when returning to the G+ state after the G- state.

[0109] In an alternative not shown, the upper end wall 61 may have a tapered shape to facilitate the flow of oil towards the channel 62 during the return to the G+ state.

[0110] Advantageously, the passage 62 allows thermal expansion of the oil using the buffer volume of the main tank 40 (the auxiliary enclosure 56). Furthermore, the passage 62 allows oil lost at the leak of the propeller pitch actuating cylinder to be re-injected into the auxiliary circuit ( Figure 2 In the circuit 48).

[0111] The tank 40 also comprises an auxiliary inlet 67 passing through the main enclosure 54 and close to the lower end wall 63, which opens tangentially to the section 60.2.

[0112] Auxiliary inlet 67 corresponds to the Figure 2 The auxiliary inlet 67 is in fact configured to eject the accelerated oil from the hydraulic control circuit towards the enclosure wall 60 to create a swirling motion or circulation flow of the oil 65 on the enclosure wall 60. This motion enables all the oil in the auxiliary enclosure to rotate during all flight phases of the aircraft (G+ and G0 and G-) to overcome gravity and reach the auxiliary outlet 74.

[0113] In practice, it is preferred that the acceleration of the oil sprayed on the enclosure wall 60 is at least 3 g (g is m / s 2 The acceleration due to gravity (unit: gravitational acceleration) may correspond to 6 g, for example. In practice, the acceleration of the oil injected at the auxiliary inlet 67 may exceed 6 g, depending on the needs and operating conditions.

[0114] Similar to the auxiliary inlet 67, the auxiliary outlet 74 is also tangential to the enclosure wall 60, specifically, to the larger diameter section 60.1 of said wall 60. In this regard, the auxiliary outlet 74 passes through the main enclosure 54 to engage Figure 1 Hydraulic control circuit 48.

[0115] Advantageously, each of the smaller diameter section 60 . 2 and the larger diameter section 60 . 1 of the enclosing wall 60 is less than 50% of the total height H of the auxiliary enclosure 56 , and preferably corresponds to 25% of the height H.

[0116] exist Figure 3 In the illustrated configuration, each of the auxiliary inlet 67 and the auxiliary outlet 74 is adjacent to the corresponding end wall 61, 63. However, the auxiliary outlet 74 may be moved closer to the auxiliary inlet 67, or vice versa.

[0117] Preferably, the swirling movement of the oil 65 on the enclosure wall 60 makes it possible to expect an acceleration of the oil of approximately 5 g at the auxiliary outlet 72 (in the example described). This value makes it possible to ensure a continuous supply of oil to the hydraulic control circuit during all flight phases of the aircraft.

[0118] Figure 3 The G event shown in shows that the oil 65 remains pressed against the enclosure wall 60 , and this plating can be achieved by centrifugal forces caused at least in part by the cone angle of the enclosure wall 60 .

[0119] The enclosure wall 60 has a main axis R corresponding to the main extension direction of said wall 60 . To this end, the main axis R defines the direction of the greatest dimension (height H) of the enclosure wall 60 .

[0120] Preferably, the main axis R is coaxial with the channel 62 or inclined at an angle less than 30° relative to the channel 62. However, the main axis R may be inclined up to 45° or more relative to the channel 62 to form an angle less than 90° with the channel 62.

[0121] Preferably, the main axis R follows the direction of gravity (perpendicular to the horizontal plane). However, the main axis R may be inclined at an angle of up to or exceeding 45° relative to the direction of gravity so as to form an angle of less than 90° with said direction of gravity.

[0122] Preferably, the wall 60 of the tank 40 has a single taper represented by a taper angle α comprised between 0° (cylindrical wall 60) and 50°, preferably between 20° and 45°, even more preferably equal to 30°. The taper angle α exists between the enclosing wall 60 and the main direction.

[0123] Furthermore, the upper end wall 61 may include a valve (not shown) or flap that is sensitive to gravity changes and enables oil to be retained in the auxiliary enclosure 56 in G- conditions and accelerated back into the enclosure in G+ conditions.

[0124] Additionally, the upper end wall 61 may also include at least one drain port (not shown) to quickly exhaust air from the auxiliary enclosure 56 so that oil can quickly return to the auxiliary enclosure 56 when the aircraft returns to the G+ state after the G- state.

[0125] The enclosure 54 may include a perforated baffle (not shown) arranged above the upper end wall 61 and enabling filtering and purification of the oil before it reaches the auxiliary enclosure 56 in the G+ state.

[0126] Figure 5 Shows Figure 3 56, in which, to the right of the end wall 63, the oil outlet 72 comprises a tube 73 extending into the channel 62 and concentric with the channel. Advantageously, this enables the auxiliary enclosure 56 to be filled preferentially to ensure the oil supply and the rapid return of the oil to the outlet 72 at all times during the return to the G+ state after the G- state.

[0127] Figure 6 yes Figure 3 A top view of the enclosing wall 60 of the oil tank.

[0128] It is possible to clearly distinguish the tangential orientation of the auxiliary inlet 67 and the auxiliary outlet 74. Advantageously, this tangential orientation of the auxiliary inlet 67 and the auxiliary outlet 74 makes it possible to limit the friction that may occur between the viscous oil and the enclosure wall 60. Advantageously, this orientation makes it possible to maintain as much as possible the velocity of the oil on the enclosure wall 60, so that the oil can have a trajectory 50 that enables the oil to quickly reach the auxiliary outlet 74.

[0129] The track 50 may be defined by a groove formed in the enclosure wall 60 .

[0130] Figure 7 A cross-sectional view of a tank 400 according to a second embodiment of the invention is shown during a flight phase when the aircraft is in a G-state.

[0131] The same elements as those in the first embodiment are denoted by the same reference numerals, and elements that are different are denoted by reference numerals increased by 100.

[0132] Reference Figure 7 , the tank 400 comprises an enclosure wall 160, which here has two opposite tapered portions. In this configuration, the enclosure wall 160 comprises two smaller diameter sections 160.2 and a larger diameter section 160.2, each smaller diameter section comprising an upper end wall 161 and a lower end wall 163, the larger diameter section corresponding to the boundary between the two tapered portions, the boundary 160.2 preferably having no wall.

[0133] The enclosure wall 160 delimits the secondary enclosure 156 within the primary enclosure 54. To this end, at least 80% of the volume of the secondary enclosure 156 is located within the primary enclosure, and preferably, the entire volume of the secondary enclosure 156 is located within the primary enclosure 54.

[0134] Preferably, the enclosure wall 160 is formed integrally with the enclosure 54. To this end, the wall 160 is connected to the enclosure by rigid tubes 67.1 and 74.1 forming the auxiliary inlet 67 and the auxiliary outlet 74, respectively. However, these tubes 67.1, 74.1 may be flexible, and the enclosure wall 160 may be rigidly connected to the enclosure by end walls 161 and / or 163 which may extend to the side walls of the enclosure 54. To this end, internal reinforcements (not shown) may rigidly connect the enclosure wall 160 to the main enclosure 54.

[0135] Preferably, each of the two end walls 161 and 163 comprises a channel 62 enabling the passage of oil here between the auxiliary enclosure 156 and the main enclosure 54 .

[0136] Figure 7The G-event shown in shows the oil having a trajectory 50 from each of the two auxiliary inlets 67 to the auxiliary outlet 74 which recovers the oil at boundary 106.2 with an acceleration of approximately 5g.

[0137] Advantageously, the tank 400 according to the second embodiment makes it possible to ensure a combination of two rotary motions within the auxiliary enclosure 156, which makes it possible to avoid changes in the volume of the accelerated oil and to avoid changes in acceleration, so that the oil in the auxiliary enclosure 156 can easily reach an acceleration of 5g in the direction of the hydraulic control circuit.

[0138] Preferably, the tank 40 according to the first embodiment of the present invention or the tank 400 according to the second embodiment is obtained by additive manufacturing.

[0139] Advantageously, the turbine of the invention is able to ensure continuous and safe operation of the variable pitch system of the turbine thanks to a main oil tank which makes it possible to ensure the oil supply during flight phases in zero or negative gravity, thereby supplying the variable pitch system with oil in the absence of any air in an uninterrupted supply.

Claims

1. An oil tank (40;) for an aircraft turbine (2); 400), the oil tank comprises: - a main capsule (54) capable of containing oil; - an oil inlet (66) for oil mixed with air, said oil inlet being arranged on said main enclosure (54); - oil outlet (72); Characterized in that the oil tank (40; 400) further comprises: - an auxiliary enclosure (56; 156) comprising an enclosure wall (60; 160) and two end walls (61, 63; 161, 163) adjacent to the enclosure wall (60), at least one of the two end walls (61, 63; 161, 163) comprising at least one oil passage (62) leading to the interior of the main enclosure (54), - at least one auxiliary inlet (67) opening tangentially to the enclosure wall (60; 160) and passing through the auxiliary enclosure (56; 156) for connection to an auxiliary circuit (48); - an auxiliary outlet (74), which is tangential to the larger diameter section (60.1; 160.1) of the enclosure wall (60; 160), the auxiliary outlet (74) passing through the auxiliary enclosure (56; 156) to be connected to the auxiliary circuit (48), the oil outlet (72) being arranged on the auxiliary enclosure (56) or on the main enclosure (54).

2. The oil tank (40; 400) according to claim 1, wherein: The enclosure wall (60; 160) is integrally formed with the primary enclosure (54), and the enclosure wall (60; 160) preferably comprises a conical shape.

3. The oil tank (40; 400) according to claim 2, wherein: The at least one auxiliary inlet (67) opens tangentially to a smaller diameter section (60.2; 160.2) of the enclosure wall (60; 160).

4. The oil tank (40; 400) according to any one of claims 1 to 3, wherein: The at least one oil passage (62) is centrally located on the corresponding end wall (61; 161, 163).

5. The oil tank (40; 400) according to any one of claims 1 to 4, wherein: The at least one oil passage (62) comprises a channel (62) extending axially from a corresponding end wall (61; 161, 163) within the auxiliary enclosure (56; 156).

6. The oil tank (40; 400) according to claim 5, wherein: The at least one channel (62) extends over at least 30% or 20% of the total axial extent of the auxiliary enclosure (54).

7. The oil tank (40; 400) according to any one of claims 1 to 6, wherein: The at least one auxiliary inlet (67) is located adjacent to one of the two end walls (63; 161, 163).

8. The oil tank (40) according to any one of claims 1 to 7, wherein: The auxiliary outlet (74) is located close to one of the two end walls (61).

9. The oil tank (40; 400) according to any one of claims 1 to 8, wherein: The enclosure wall (60; 160) has a cone angle (α) between 0° and 50°.

10. The oil tank (40) according to any one of claims 1 to 9, wherein: The enclosure wall (60) includes a single tapered portion.

11. The oil tank (400) according to any one of claims 1 to 10, wherein: The conical enclosure wall (160) includes two opposite conical portions, and the auxiliary outlet (74) is located at a boundary (160.1) between the two conical portions.

12. The oil tank (400) according to claim 10, wherein: The at least one auxiliary inlet (67) comprises an auxiliary inlet (67) at each of the two axial ends (161, 163) of the conical wall (160).

13. The oil tank (40; 400) according to any one of claims 1 to 11, wherein: When the oil tank (40; 400) is oriented in a normal installation position, at least 80% of the volume of the auxiliary enclosure (56; 156) is located in the lower half of the main enclosure (54).

14. The oil tank (40; 400) according to any one of claims 1 to 13, wherein: The enclosure wall (60; 160) has a main axis (R) which is coaxial with the channel (62) or inclined at an angle less than 45° relative to the channel (62).

15. A hydraulic system (39) for an aircraft turbine (2), the hydraulic system comprising: -Oil tank (40; 400)； - a lubrication circuit (42) of the turbine (2), the lubrication circuit being hydraulically connected to the oil tank (40; 400); - a hydraulic control circuit (48) of at least one hydraulic actuator (52), the hydraulic control circuit being hydraulically connected to the oil tank (40; 400); characterised in that the oil tank (40; 400) is an oil tank according to any one of claims 1 to 14.

16. The hydraulic system (39) according to claim 15, wherein: The lubrication circuit (42) is hydraulically connected to the oil inlet (66) and the oil outlet (72) of oil mixed with air, and the hydraulic control circuit (48) is hydraulically connected to the at least one auxiliary inlet (67) and the auxiliary outlet (74).

17. An aircraft turbomachine (2), comprising: - an unducted propeller (14) which propels the incoming air flow (F), the propeller (14) comprising variable pitch blades (28) actuated by at least one hydraulic actuator (52); a hydraulic system (39) capable of providing lubrication for the turbine (2) and of controlling the at least one hydraulic actuator (52); Characterized in that the hydraulic system (39) is a hydraulic system according to claim 15 or 16.

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