Auxiliary oil tank for an aircraft turbine engine

Abstract

The invention relates to an auxiliary oil tank (20) including an enclosure (200) that comprises: a first internal volume (V1) in fluid communication with the first outlet port (201), a second internal volume (V2) in fluid communication with the second outlet port (202) and separated from the first internal volume (V1) by a baffle (204), the baffle (204) comprising a first end wall (204a) extending from the top wall (200a) towards the bottom wall (200b) and a second end wall (204b) extending from the bottom wall (200b) towards the top wall (200a), the first and second end walls (204a, 204b) being substantially parallel, the first end wall (204a) and the lower wall (200b) delimiting a first fluid passage (P1), and the second end wall (204b) and the upper wall (200a) delimiting a second fluid passage (P2).

Description

Technical field of the invention

[0001] The invention relates to the field of oil tanks for aircraft turbomachinery. More particularly, the invention relates to the field of oil tanks for flight phases during which the gravitational force is zero (0g condition) or negative (negative g condition). Technical background

[0002] The prior art is illustrated by documents US-A1-2020116048, FR-A1-3105296 and US-A1-2015060206.

[0003] A turbomachine for an aircraft comprises, from upstream to downstream, at least one first rotor, also called the propulsion rotor, such as a propeller when the turbomachine is a turboprop, or an unshod fan when the turbomachine is an open rotor type, or a shod fan when the turbomachine is a turbojet, a compressor, a combustion chamber, and a turbine. The compressor rotor is connected to the turbine rotor and the first rotor by a drive shaft. An airflow is compressed within the compressor, then the compressed air is mixed with fuel and burned in the combustion chamber. The gases produced by the combustion pass through the turbine, which drives the compressor rotor and the propulsion rotor.

[0004] The propeller or fan of the propulsion rotor, as well as the compressor rotor, are equipped with blades that influence the airflow. To adapt the turbomachine to flight conditions, it is common practice to equip the propulsion rotor or compressor rotor with variable-pitch blades. For this purpose, the turbomachine includes a variable-pitch blade control system comprising a control unit connected to a hydraulic actuator to rotate the blades around a longitudinal axis according to the airflow direction.

[0005] To supply oil to the control system, including the hydraulic actuator, as well as other turbomachine components such as bearings and gearboxes, the turbomachine typically includes a main oil supply system. This supply system comprises, for example, a main reservoir connected to a first supply circuit for bearing lubrication and a second supply circuit for supplying oil to the hydraulic actuator. A feed pump is mounted on the second supply circuit and draws oil from the main reservoir and circulates it to the hydraulic actuator. The main reservoir typically consists of a housing with a lower and upper wall connected by transverse walls. The lower wall includes an opening connected to the pump for oil intake.

[0006] Certain flight phases of the aircraft disrupt the oil supply to the hydraulic actuator. Specifically, the aircraft may experience flight phases during which the gravitational force is zero or negative. These flight phases are referred to in the field of this invention as the "0g condition" when the gravitational force is zero, or the "negative g condition" when the gravitational force is reversed. During such flight phases, the oil in the main reservoir becomes trapped against the upper wall of the reservoir opposite the orifice in the negative g condition, or the oil and air form a suspension laden with air bubbles in the 0g condition. Consequently, the pump no longer draws oil from the reservoir but rather air or oil heavily laden with air bubbles, which degrades the oil supply to the control system and can even cause the supply pump to shut down.In all cases, the hydraulic actuator of the control system is no longer properly supplied with oil.

[0007] Such a degradation of the oil supply to the control system, and particularly to the hydraulic actuator, can render the pitch of the propulsion rotor blades uncontrollable, especially the blades of the propeller or the unshod fan, which can lead to the blades being feathered by a safety system. This results in a significant reduction in the turbomachine's thrust and leads to a loss of control, which is unacceptable.

[0008] Therefore, there is a need to provide an oil reservoir that allows oil to be supplied to the variable pitch blade control system during flight phases in which the gravitational force is zero or negative. Summary of the invention

[0009] To this end, the invention proposes an auxiliary oil reservoir for supplying a blade pitch control system of an aircraft turbomachine, comprising a housing including: a lower wall and an upper wall connected by transverse walls, a first outlet port intended to be connected to a main oil reservoir, a second outlet port intended to be connected to the control system by a second oil supply circuit, a first inlet port intended to be connected to the control system by an auxiliary recovery circuit.

[0010] The enclosure is characterized by the fact that it also includes: a first internal volume in fluidic communication with the first outlet port, a second internal volume in fluidic communication with the second outlet port, and separated from the first internal volume by a baffle, the baffle comprising a first end wall extending from the upper wall to the lower wall and a second end wall extending from the lower wall to the upper wall, the first and second end walls being substantially parallel, the first end wall and the lower wall delimiting a first fluid passage, and the second end wall and the upper wall delimiting a second fluid passage.

[0011] The tank according to the invention therefore includes a baffle that separates the first internal volume from the second internal volume. When the aircraft experiences a flight phase during which the gravitational force is zero or negative, the air entering through the first outlet port flows from the first internal volume to the second internal volume. According to the invention, the airflow between the two volumes is slowed by the baffle, allowing the oil contained in the second internal volume to remain connected to the second outlet port to supply the second circuit. Thus, the air does not reach the second outlet port. Thanks to the invention, the auxiliary tank is able to supply the control system during such a flight phase. The turbine blades are therefore not feathered, and the aircraft turbomachine maintains maximum thrust during this flight phase.

[0012] The invention may include one or more of the following features, taken individually or in combination with each other: the first end wall and the second end wall delimit an intermediate volume, the sum of the first volume and the intermediate volume being equal to the second internal volume; the first end wall and the second end wall delimit an intermediate volume, the sum of the first volume and the intermediate volume being less than the second internal volume; the baffle comprises a first intermediate wall and a second intermediate wall which are arranged substantially parallel and between the first and second end walls, the first intermediate wall delimiting with the upper wall a third fluid passage and the second intermediate wall delimiting with the lower wall a fourth fluid passage, the first intermediate wall being arranged between the first end wall and the second intermediate wall;The upper wall of the enclosure comprises a first portion substantially parallel to the lower wall and a second portion inclined towards the interior of the enclosure, the first and second portions forming a peak directed outwards from the enclosure; the first internal volume is between 1 L and 50 L and the second internal volume is between 1 L and 50 L; the enclosure further comprises a second inlet port intended to be connected to a valve.

[0013] The invention also relates to a turbomachine for an aircraft comprising: variable pitch angle blades, a blade control system including a control unit connected to at least one hydraulic actuator, an oil supply system including: a main supply system including: a second supply circuit for the control system, a main reservoir connected to the second supply circuit, and an oil supply pump mounted on the second supply circuit and including an inlet and an outlet connected to the control system, an auxiliary supply device including: an auxiliary oil reservoir according to any one of the preceding characteristics, the first outlet port being connected to the main reservoir, the second outlet port being connected to the second supply circuit and the first inlet port being connected to the control system.

[0014] The turbomachine may include one or more of the following features, taken individually or in combination with each other: the auxiliary supply device further includes a valve comprising a body having a first inlet connected to the main tank, a second inlet connected to the second outlet port of the auxiliary tank and an outlet connected to the inlet of the supply pump, the valve further comprising a movable member in the body and configured to move between a first position in which the first inlet of the valve is in fluidic communication with the outlet of the valve and a second position in which the second inlet of the valve is in fluidic communication with the outlet of the valve;The auxiliary tank includes a second inlet port, and the auxiliary supply device includes a valve comprising a body having an inlet connected to the auxiliary tank and a first outlet connected to the second inlet port of the auxiliary tank, and a second outlet connected to the control system, the valve further comprising a movable member in the body configured to move between a first position in which the inlet of the valve is in fluidic communication with the first outlet of the valve and a second position in which the inlet of the valve is in fluidic communication with the second outlet of the valve; the inlet of the supply pump is connected to the main tank. Brief description of the figures

[0015] Other features and advantages will become apparent from the following description of a non-limiting embodiment of the invention with reference to the accompanying drawings in which: [ Fig.1 ] there figure 1 is a schematic longitudinal cross-sectional representation of half an aircraft turbomachine according to a first embodiment of the invention; [ Fig. 2 ] there figure 2 is a schematic perspective representation of an aircraft turbomachine according to a second embodiment of the invention; [ Fig.3 ] there figure 3 is a schematic longitudinal cross-sectional representation of an aircraft turbomachine according to a third embodiment of the invention; [ Fig. 4 ] there figure 4 is a schematic representation of an oil supply system according to a first embodiment of the invention; [ Fig. 5 ] there figure 5 is a schematic representation of an oil supply system according to a second embodiment of the invention; [ Fig. 6 ] there figure 6 is a schematic cross-sectional representation of an auxiliary oil reservoir according to the invention; [ Fig. 7 ] there figure 7is a partial schematic and cross-sectional representation of the auxiliary oil reservoir according to an example of an embodiment of the invention; Detailed description of the invention

[0016] A turbomachine 1, 1', 1" for an aircraft is represented for example on the figures 1 to 3 The turbomachine 1, 1, 1" comprises a first rotor 2 connected to an engine M extending around a longitudinal axis X. The engine M comprises, from upstream to downstream in the direction of flow of a main airflow F along the longitudinal axis X, a compressor such as a low-pressure compressor 3 and a high-pressure compressor 4, a combustion chamber 5, a turbine such as a high-pressure turbine 6 and a low-pressure turbine 7, and a nozzle 8.

[0017] 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 rotor of the low-pressure turbine 7 is connected to the rotor of the low-pressure compressor 3 by a low-pressure shaft 10.

[0018] The low-pressure shaft 10 and high-pressure shaft 9 are supported by bearings 12a. The bearings 12a are contained within a lubrication chamber 12 for lubrication. For example, an upstream bearing 120a is arranged radially between an upstream end of the low-pressure shaft 10 and an upstream bearing support 120b, and a downstream bearing 120a' is arranged downstream of the upstream bearing 120a and radially between the low-pressure shaft 10 and a downstream bearing support 120b'. The lubrication chamber 12 is annular. The upstream and downstream bearings 120a and 120a' are arranged within the lubrication chamber 12.

[0019] The first rotor 2 is driven in rotation by a rotor shaft 100. The rotor shaft 100 is connected to the low-pressure shaft 10. The low-pressure shaft 10 drives the rotor shaft 100 in rotation. Advantageously, the low-pressure shaft 10 is connected to the rotor shaft 100 by a speed reducer 11. This allows the first rotor 2 to be driven at a speed lower than the rotational speed of the low-pressure shaft 10. The speed reducer 11 is, for example, arranged in the lubrication chamber 12 between the upstream bearing 120a and the downstream bearing 120a'.

[0020] The main airflow F passes through the turbomachine 1, 1', 1" and splits into a primary airflow F1 which passes through the engine M within a primary channel and a secondary airflow F2 which passes through the first rotor 2 in a secondary channel surrounding the primary channel.

[0021] The turbomachine 1, 1', 1" includes blades 2a which act on the main airflow F, or primary F1, or the secondary airflow F2. For example, the rotors of the low-pressure 3 and high-pressure 4 compressors include blades 2a which compress the primary airflow F1 upstream of the combustion chamber 5.

[0022] In general, the 2a blades can be fixed in rotation around the longitudinal axis X, or can be mobile in rotation around the longitudinal axis X or an axis parallel to the longitudinal axis X.

[0023] According to a first embodiment shown on the figure 1The turbomachine 1 is a turbofan engine. In this embodiment, the first rotor 2 is a shrouded fan arranged upstream of the engine M. The fan comprises blades 2a. The fan blades 2a are rotatable about the longitudinal axis X. They are, for example, supported by a disk centered on the longitudinal axis X. The blades 2a are arranged inside a fan casing 2b. The casing 2b is surrounded by a nacelle (not shown).

[0024] According to a second embodiment shown in the figure 2The turbomachine 1' is a turbojet engine with an unfaired fan. In this embodiment, the first rotor 2 is an unfaired fan comprising blades 2a. In this embodiment, the fan is arranged downstream of the engine M (not visible in this figure). The fan is rotatable about the longitudinal axis X. The fan blades 2a are supported by a disk that rotates about the longitudinal axis X. In addition, in this embodiment, a straightener 2' is optionally arranged downstream of the fan 2 to straighten the secondary airflow F2. The straightener 2' forms a fixed blade about the longitudinal axis X. It comprises blades 2a that may have variable pitch. The blades 2a are mounted outside the nacelle.

[0025] According to a third embodiment shown in the figure 3The turbomachine 1" is a turboprop. According to this embodiment, the first rotor 2 is a propeller arranged upstream of the engine M. The propeller rotates about a propeller axis H parallel to the longitudinal axis X, and comprises blades 2a. The blades 2a are supported by a disk centered on the propeller axis H. The blades 2a are, for example, at least two in number and evenly distributed on the disk.

[0026] The blades 2a extend radially with respect to the longitudinal axis X. They typically comprise a blade and a mounting element for attaching to the disk. The mounting element is, for example, a foot or a platform. According to the invention, the blades 2a have a variable pitch angle. By variable pitch angle, it is understood that the blades 2a are free to rotate about a transverse axis Z that is substantially perpendicular to the longitudinal axis X.

[0027] To control the pitch angle of the blades 2a, the turbomachine 1, 1', 1" according to the invention includes a control system 13 for the variable pitch-angle blades 2a. The control system 13 comprises a control unit 13a and at least one hydraulic actuator 13b supplied with oil. The control unit 13a is, for example, fixed in rotation about the longitudinal axis X. The control unit 13a is, for example, connected to a stator of the turbomachine 1, 1', 1". The control unit 13a is known in the field of the invention by the acronym PCU for "Pitch Control Unit". The hydraulic actuator 13b is, for example, a hydraulic cylinder comprising a movable rod connected to the blade 2a, optionally via a motion transformation mechanism. The translational movement of the rod allows the blade 2a to be rotated about its axis.The translational movement of the movable rod is controlled by the control unit 13a, which supplies oil to the hydraulic actuator 13b. The hydraulic actuator 13b rotates about the longitudinal axis X or about an axis parallel to the longitudinal axis X. For example, the hydraulic actuator 13b is rotationally fixed to the vanes 2a. The hydraulic actuator 13b is, for example, arranged upstream of the control unit 13a.

[0028] The control system 13 advantageously includes an oil transfer device 13c from the control unit 13a to the hydraulic actuator 13b. The oil transfer device 13c ensures the transfer of oil from the stationary control unit 13a to the rotating hydraulic actuator 13b. The oil transfer device 13c is known by the acronym OTB for "Oil Transfer Bearing." The oil transfer device 13c is, for example, arranged within the lubrication chamber 12.

[0029] The turbomachine 1, 1', 1" further includes an electrical control unit 24. The electrical control unit 24 allows the control unit 13a to be operated. The electrical control unit 24 is, for example, a FADEC (for "Full Authority Digital Engine Control").

[0030] In addition, the turbomachine 1, 1', 1" includes an oil supply system comprising a main supply system 14 and an auxiliary supply device 14', shown in the figures 4 And 5 .

[0031] The main supply system 14 provides lubrication of the bearings 12a within the lubrication enclosure 12 and of the reducer 11 and supplies oil to the control system 13 during a first phase of operation of the turbomachine 1, 1', 1". The auxiliary supply device 14' provides lubrication of the control system 13 during a second phase of operation of the turbomachine 1, '1, 1" during which the gravitational force is zero (0g condition) or reversed (negative g condition).

[0032] The main oil supply system 14 comprises a first supply circuit 14a for the lubrication chamber 12 and a second supply circuit 14b for the control system 13. The main supply system 14 advantageously includes a metering valve 19 with a variable diaphragm. The metering valve 19 supplies oil to the speed reducer 11. In a first embodiment, this metering valve 19 can also function as a distribution valve for the oil distributed between the lubrication chamber 12 and the speed reducer 11.

[0033] The main supply system 14 advantageously includes an oil recovery circuit 14a' from the lubrication chamber 12 and an oil recovery circuit 14b' from the control system 13.

[0034] The main supply system 14 also includes a main oil reservoir 15 connected to the first supply circuit 14a and the second supply circuit 14b.

[0035] The oil sent to the bearings 12a, for example the upstream bearing 120a and the downstream bearing 120a', to the reducer 11 and the oil leaks from the transfer device 13c, fall back into the bottom of the lubrication enclosure 12. In order to optimize oil consumption, this oil is recovered and directed for example into the oil recovery circuit 14a' of the lubrication enclosure 12.

[0036] The first supply circuit 14a includes a first supply pump 16a allowing the suction of oil from the main reservoir and its circulation in the first supply circuit 14a to supply oil to the lubrication chamber 12. Advantageously, the first supply circuit 14a includes a main heat exchanger 17a for example air / oil or oil / fuel, and optionally a second heat exchanger 17b for example oil / fuel which are arranged between the first pump 16a and the lubrication chamber 12.

[0037] The oil recovery circuit 14a' from the lubrication chamber 12 includes a second recovery pump 16b connected to the lubrication chamber 12 and to the main reservoir 15. The pump 16b allows the oil to be recovered from the lubrication chamber 12 and returned to the main reservoir 15 through the recovery circuit 14a'.

[0038] Furthermore, the main supply system 14 includes a supply pump 18 dedicated to supplying oil to the control system 13. The supply pump 18 is, for example, mounted on the secondary supply circuit 14b. The supply pump 18 is, for example, a positive displacement pump. The positive displacement pump is, for example, of fixed or variable displacement. The supply pump 18 includes an inlet 18a and an outlet 18b connected to the control system 13.

[0039] The second supply circuit 14b may include a filter 26 arranged between the supply pump 18 and the control system 13.

[0040] During the first phase of operation of the turbomachine 1, 1', 1", the first pump 16a draws oil from the main reservoir 15 and allows the oil to circulate in the first supply circuit 14a to the lubrication chamber 12. The supply pump 18 also draws oil from the main reservoir 15, for example upstream or downstream of the first pump 16a and conveys the oil in the second supply circuit 14b to the control system 13.

[0041] During the second phase of operation, typically negative (or inverted) gravity flight, oil is trapped in the upper part of the main reservoir 15, while the lower part, connected to the first pump 16a, is filled with air. In zero gravity, an air-oil mixture is suspended in the reservoir 15, and in inverted gravity, air occupies the lower part of the main reservoir 15 connected to the first pump 16a. The feed pump 18 is indirectly connected to the lower part of the main reservoir 15 and therefore risks drawing air from the main reservoir 15, or oil heavily laden with air bubbles. This is unacceptable because the control system 13 must be supplied with oil that is relatively free of air bubbles, so as not to compromise the operation of the control unit 13a and thus the hydraulic actuator 13b, which controls the pitch of the blades 2a.Also, the presence of air can lead to the shutdown of the feed pump 18. Therefore, in order to ensure a suitable oil supply for the control system 13 during the second operating phase of the turbomachine 1, 1', 1", the invention proposes an auxiliary supply device 14'. The auxiliary supply device 14' is mounted on the second supply circuit 14b.

[0042] The auxiliary supply device 14' includes an auxiliary oil reservoir 20, optionally an auxiliary pump 22 and a valve 21. The auxiliary pump 22 has an inlet 22a and an outlet 22b. The valve 21 is, for example, a 3 / 2 hydraulic distributor, i.e., having three ports and two positions.

[0043] According to a first embodiment shown on the figure 4The auxiliary pump 22 is arranged between the valve 21 and the auxiliary reservoir 20. The inlet 22a of the pump 22 is connected to the auxiliary reservoir 20. The auxiliary pump 22 is a fixed-displacement hydraulic pump. The auxiliary power supply device 14' advantageously includes a rotary motor to drive the auxiliary pump 22. Alternatively, the auxiliary pump 22 is driven by the low-pressure shaft 10 or the high-pressure shaft 9.

[0044] According to this embodiment, the valve 21 is a hydraulically actuated, spring-return valve. The valve 21 has a body 21a with an inlet connected to the outlet 22b of the auxiliary pump 22, a first outlet connected to the auxiliary reservoir 20, and a second outlet connected to the second supply circuit 14b, between the supply pump 18 and the control system 13. The valve 21 further includes a movable element within the body 21a configured to move between a first position in which the inlet of the valve 21 is in fluid communication with the first outlet of the valve 21, and a second position in which the inlet of the valve 21 is in fluid communication with the second outlet of the valve 21. The valve 21 includes, for example, a return spring for returning the movable element from the second position to the first position.

[0045] It is thus understood that in the first position as illustrated on the figure 4 The auxiliary pump 22 draws oil from the auxiliary reservoir 20 and the oil is redirected to the auxiliary reservoir 20. The control system 13 is supplied with oil by the supply pump 18 which draws oil from the main reservoir 15.

[0046] In the second position (not shown), the auxiliary pump 20 draws oil from the auxiliary reservoir 20, and the oil is delivered to the control system 13 via the second supply circuit 14b, for example. Thus, when the turbomachine 1, 1', 1" is in the first operating phase, particularly when the aircraft is in a so-called "normal" flight phase, the valve 21 is in the first position. When the turbomachine 1, 1', 1" is in the second operating phase, particularly when the aircraft is in a flight phase in which the gravitational force is zero (referred to as "0g") or negative (referred to as "negative g"), the valve 21 is in the second position. This ensures the oil supply to the control system 13 from the auxiliary reservoir 20 and prevents any interruption in the oil supply to the control system 13.Also, the auxiliary pump 22 is active both when the moving part of the valve 21 is in the first position and in the second position. This eliminates the need for priming time for the auxiliary pump 22 and ensures a rapid oil supply to the control system 13 during the second operating phase of the turbomachine 1, 1', 1".

[0047] The valve 21 includes a hydraulic actuating chamber connected to the inlet 18a of the feed pump 18. When the turbomachine 1, 1', 1" is in the second operating phase (negative or zero gravity), the pressure in the first feed circuit 14a drops because the first pump 16a draws air or an air-oil mixture from the main reservoir 15. The pressure at the inlet 18a of the feed pump 18 connected to the first feed circuit 14a then falls below a threshold pressure, which causes the moving part of the valve 21 to move into the second position under the action of the valve spring. This configuration simplifies the control of the valve 21. The valve does not require a special sensor since its actuation is triggered by the sharp drop in pressure at the inlet 18a of the feed pump 18.

[0048] Alternatively, valve 21 is directly sensitive to gravitational force.

[0049] Furthermore, according to this first embodiment, advantageously, the auxiliary supply device 14' further includes a pressure limiter 25a arranged at the outlet of the auxiliary pump 22, between the auxiliary pump 22 and the valve 21. The pressure limiter 25a is, for example, a non-return valve.

[0050] According to this first embodiment, the metering valve 19 is mounted on the first supply circuit 14a. The metering valve 19 is mounted between the first pump 16a and the lubrication chamber 12. Preferably, the metering valve 19 is mounted between the main heat exchanger 17a, which in this embodiment is an oil / fuel heat exchanger, and the second heat exchanger 17b. In this first embodiment, the metering valve 19 functions as a distribution valve for the oil supplied between the lubrication chamber 12 and the speed reducer 11. It is a two-outlet valve. The first outlet of the metering valve 19 is connected to the lubrication chamber 12, and the second outlet of the metering valve 19 is connected to the speed reducer 11. The metering valve 19 is, for example, controlled by the electrical control unit 24.

[0051] In addition, according to this example, a third exchanger 17c, for example air / oil, connects the second outlet of the metering valve 19 and the reducer 11.

[0052] According to a preferred embodiment of the invention, the supply pump 18 includes a check valve 25b to ensure that all the oil delivered by the auxiliary pump 22 supplies the control system 13.

[0053] According to a second embodiment shown in the figure 5The valve 21 has a body 21a with a first inlet connected to the main tank 15 and a second inlet connected to the auxiliary tank 20. The valve 21 further includes an outlet connected to the inlet 18a of the feed pump 18. The valve 21 also includes a movable element within the body configured to move between a first position in which the first inlet is in fluid communication with the outlet and a second position in which the second inlet is in fluid communication with the outlet. The valve 21 includes, for example, a return spring allowing the movable element to return from the second position to the first position. The outlet 18b of the feed pump 18 is connected to the control circuit 13.

[0054] It is thus understood that in the first position, the supply pump 18 draws oil from the main reservoir 15, and in the second position, the supply pump 18 draws oil from the auxiliary reservoir 20. The valve 21 thus allows control of the oil flow in the second circuit 14b. When the turbomachine 1, 1', 1" is in a first phase of operation, particularly when the aircraft is in a so-called "normal" flight phase, the valve 21 is in the first position and the main pump 18 draws oil from the main reservoir 15 to supply the control system 13.When the turbomachine 1, 1', 1" is in a second phase of operation, in particular when the aircraft is in a phase of flight in which the gravitational force is zero (called 0g condition) or negative (called negative g condition), the valve 21 is in the second position and the main pump 18 draws oil from the auxiliary tank 20 to supply oil to the control system 13.

[0055] According to a first embodiment, the valve 21 is electrically controlled. In this example, the turbomachine 1, 1', 1" includes a sensor configured to deliver a signal to the electrical control unit 24. The sensor is configured to detect the second operating phase of the turbomachine 1, 1', 1". The sensor is, for example, an accelerometer. According to a second embodiment, the moving part of the valve 21 is directly sensitive to the gravitational force acting on the turbomachine 1, 1', 1". When the gravitational force exceeds a given threshold, i.e., in the first operating state, the moving part is in the first position. During the second operating state, the moving part detects the second operating state and moves to the second position.

[0056] The auxiliary pump 22 in this second embodiment is optional. The auxiliary pump 22 is, for example, a centrifugal pump connected to the outlet of valve 21. The auxiliary pump 22 is therefore arranged between valve 21 and the feed pump 18. The inlet 18a of the pump is thus connected to the outlet of valve 21 via the auxiliary pump 22. Optionally, a second air / oil heat exchanger 23 is arranged between valve 21 and the feed pump 18. More specifically, the second air / oil heat exchanger 23 is arranged between the centrifugal pump 22 and the feed pump 18. The centrifugal pump 22 and the second air / oil heat exchanger 23 are mounted on the second supply circuit 14b.

[0057] According to this embodiment, the metering valve 19 is mounted on the second supply circuit 14b. The metering valve 19 is mounted between the supply pump 18 and the reducer 11, and comprises a single outlet connected to the lubrication chamber 12. In this embodiment, the metering valve 19 does not have a flow distribution function between two outlets. The supply pump 18 is mounted in parallel on the second circuit 14b between the valve 21, and in particular the second air / oil heat exchanger 23 when present, and the metering valve 19.

[0058] Advantageously, the metering valve 19 is able to open when the valve 21 is in the first position, thus supplying oil to the gearbox 11 from the main reservoir 15, and is able to remain open and / or close when the valve 21 is in the second position. Preferably, the metering valve 19 is able to close when the valve 21 is in the second position. This avoids supplying oil to the gearbox 11 from the auxiliary reservoir 20, so that the control system 13 is supplied exclusively from the auxiliary reservoir 20. Thus, the auxiliary reservoir 20 is sized to supply only the control system 13, making it less bulky. Advantageously, the variable opening of the metering valve 19 is controlled by the electrical control unit 24. The electrical control unit 24 sends a signal to the metering valve 19 to open or close it according to the operating phase.

[0059] The auxiliary tank 20 according to the invention is, for example, shown on the figure 6 The auxiliary tank 20 is configured to deliver oil during the second phase of operation of the turbomachine 1, 1', 1".

[0060] The auxiliary tank 20 comprises a housing 200. The housing 200 is, for example, metallic. The housing 200 is, for example, polygonal. It comprises an upper wall 200a and a lower wall 200b connected by opposing transverse walls 200c, 200d. The transverse walls 200c, 200d may be parallel to each other. The upper wall 200a comprises, for example, a first portion 200a1 parallel to the lower wall 200b and a second portion 200a2 inclined towards the interior of the housing 200. The first portion 200a1 and the second portion 200a2 meet at a vertex O oriented towards the exterior of the housing 200. Such a configuration optimizes the flow of oil in the second supply circuit 14b during the second operating phase of the turbomachine 1, 1', 1".Indeed, the summit O represents a high point for oil recovery, which normally eliminates the risk of air being present at this level in a negative gravity situation.

[0061] The enclosure 200 has a first outlet port 201 connected to the main reservoir 15, for example, by a first pipe 201a, a second outlet port 202 connected to the second supply circuit 14b by valve 21 or auxiliary pump 22, an inlet port 203 connected to the control system by the oil recovery circuit 14b' of the control system 13, and optionally a second inlet port 206 connected to valve 21. The first outlet port 201 is, for example, provided on the transverse wall 200c, and the first inlet port 203 is, for example, provided on the opposite transverse wall 200d. The second outlet port 202 is, for example, provided on the upper wall 200a, for example, at the apex O.

[0062] The enclosure 200 defines a total volume, for example, between 2 L and 100 L, advantageously between 2 L and 40 L, and preferably between 4 L and 30 L. The enclosure 200 comprises a first internal volume V1 in fluidic communication with the first output port 201 and a second internal volume V2 in fluidic communication with the second output port 202. The first internal volume V1 is between 1 L and 50 L, advantageously between 1 L and 20 L, and even more advantageously between 2 L and 15 L. The second internal volume V2 is between 1 L and 50 L, advantageously between 1 L and 20 L, and even more advantageously between 2 L and 15 L. Preferably, the first internal volume V1 is smaller than the second internal volume V2.

[0063] The auxiliary tank 20 further includes a baffle 204 arranged within the enclosure 200, which separates the first internal volume V1 from the second internal volume V1. The baffle 204 comprises a first end wall 204a extending from the upper wall 200a to the lower wall 200b and a second end wall 204b extending from the lower wall 200b to the upper wall 200a. The first and second end walls 204a, 204b are, for example, parallel to the transverse walls 200c, 200d. The first and second end walls 204a, 204b are arranged between the first outlet port 201 and the second outlet port 202. The first end wall 204a and the lower wall 200b define a first fluid passage P1, and the second end wall 204b and the upper wall 200a define a second fluid passage P2. The fluid is, for example, air and / or oil.

[0064] The first end wall 204a and the second end wall 204b define an intermediate volume V3. In a first example, the sum of the first volume V1 and the intermediate volume V3 equals the second internal volume V2. This ensures that the internal volume V2 will contain exclusively oil during the second phase of operation.

[0065] According to another embodiment, the sum of the volume of the pipeline 201a connecting the first inlet port 201 to the main tank 15, the first volume V1, and the intermediate volume V3 is equal to the second internal volume V2. Therefore, the sum of the first volume V1 and the intermediate volume V3 is less than the second internal volume V2 in this example. Furthermore, the volume of the pipeline 201a can be sized to be equal to the volume of oil consumed during the second operating phase of the turbomachine 1, 1', 1".

[0066] As illustrated on the figure 7Advantageously, the baffle 204 further comprises a first intermediate wall 204c and a second intermediate wall 204d which are arranged parallel and between the first and second end walls 204a, 204b, the first intermediate wall 204c delimiting with the upper wall 200a a third fluid passage P3 and the second intermediate wall 204d delimiting with the lower wall 200b a fourth fluid passage P4, the first intermediate wall 204c being arranged between the first end wall 204a and the second intermediate wall 204d.

[0067] During the first phase of operation of the turbomachine 1, 1', 1", the auxiliary reservoir 20 is supplied with oil by the control system 13. Excess oil is transferred to the main reservoir 15. This transfer is ensured by the pipe 201a. The control system 13 is supplied with oil from the main reservoir 15.

[0068] During the second operating phase of the turbomachine 1, 1', 1", air enters the auxiliary tank 20 via the first outlet port 201. This is because the oil flow rate exiting the tank is lower than the incoming flow rate. However, thanks to the baffle 204, the passage of air from the first internal volume V1 to the second internal volume V2 is slowed. Thus, the feed pump 18 or the auxiliary pump 22 draws oil and not air or oil heavily laden with air, which allows the control system 13 to be supplied during the second operating phase. Advantageously, the volume of the pipe 201a and the baffle 204a is equal to the volume of oil exiting through the second outlet port 202 during the second operating phase.

[0069] Such an auxiliary tank 20 according to the invention has the advantage of being simple and reliable. For example, such an auxiliary tank 20 does not use any moving parts in managing the air intake from the main tank 15. For example, the first outlet port 201 can remain open and no closing mechanism is used. Also, the baffle 204 is fixed, which is easily designed and improves reliability compared to a moving part such as a piston.

Claims

1. An auxiliary oil tank (20) for supplying a control system (13) for controlling the pitch of vanes (2a) of an aircraft turbine engine (1, 1', 1"), comprising an enclosure (200) comprising: a lower wall (200b) and an upper wall (200a) connected by transverse walls (200c, 200d), a first outlet port (201) intended to be connected to a main oil tank (15), a second outlet port (202) intended to be connected to the control system (13) via a second oil supply circuit (14b), a first inlet port (203) intended to be connected to the control system (13) via an auxiliary recovery circuit (14b'), characterised in that the enclosure (200) further comprises: a first internal volume (V1) in fluid communication with the first outlet port (201), a second internal volume (V2) in fluid communication with the second outlet port (202), and separated from the first internal volume (V1) by a baffle (204), the baffle (204) comprising a first end wall (204a) extending from the upper wall (200a) towards the lower wall (200b) and a second end wall (204b) extending from the lower wall (200b) towards the upper wall (200a), the first and second end walls (204a, 204b) being substantially parallel, the first end wall (204a) and the lower wall (200b) defining a first fluid passage (P1), and the second end wall (204b) and the upper wall (200a) defining a second fluid passage (P2).

2. The tank according to the preceding claim, characterised in that the first end wall (204a) and the second end wall (204b) delimit an intermediate volume (V3), the sum of the first volume (V1) and of the intermediate volume (V3) being equal to the second internal volume (V2).

3. The tank according to claim 1, characterised in that the first end wall (204a) and the second end wall (204b) define an intermediate volume (V3), the sum of the first volume (V1) and of the intermediate volume (V3) being less than the second internal volume (V2).

4. The tank according to any one of the preceding claims, characterised in that the baffle (204) comprises a first intermediate wall (204c) and a second intermediate wall (204d) which are arranged substantially parallel to and between the first and second end walls (204a, 204b), the first intermediate wall (204c) delimiting with the upper wall (200a) a third fluid passage (P3) and the second intermediate wall (204d) delimiting with the lower wall (200b) a fourth fluid passage (P4), the first intermediate wall (204c) being arranged between the first end wall (204a) and the second intermediate wall (204d).

5. The tank according to any one of the preceding claims, characterised in that the upper wall (200a) of the enclosure (200) comprises a first segment (200a1) substantially parallel to the lower wall (200b) and a second segment (200a2) inclined towards the inside of the enclosure (200), the first and second segments (200a1, 200a2) forming a top (O) directed towards the outside of the enclosure (200).

6. The tank according to any one of the preceding claims, characterised in that the first internal volume (V1) is between 1 L and 50 L and the second internal volume (V2) is between 1 L and 50 L.

7. The tank according to any one of the preceding claims, characterised in that the enclosure (200) further comprises a second inlet port (206) intended to be connected to a valve (21).

8. A turbine engine (1, 1', 1") for an aircraft comprising: variable pitch angle vanes (2a), a control system (13) for controlling the pitch of the vanes (2a) comprising a control unit (13a) connected to at least one hydraulic actuator (13b), an oil supply system comprising: a main supply system (14) comprising: a second supply circuit (14b) for supplying the control system (13), a main tank (15) connected to the second supply circuit (14b), and an oil supply pump (18) mounted on the second supply circuit (14b) and comprising an inlet (18a) and an outlet (18b) connected to the control system (13), an auxiliary supply device (14') comprising: an auxiliary oil tank (20) according to any of the preceding claims, the first outlet port (201) being connected to the main tank (15), the second outlet port (202) being connected to the second supply circuit (14b) and the first inlet port (203) being connected to the control system (13).

9. The turbine engine according to the preceding claim, characterised in that the auxiliary supply device (14') further comprises a valve (21) comprising a body (21a) having a first inlet connected to the main tank (15), a second inlet connected to the second outlet port (202) of the auxiliary tank (20) and an outlet connected to the inlet (18a) of the supply pump (18), the valve (21) further comprising a member movable within the body and configured to move between a first position in which the first inlet of the valve (21) is in fluid communication with the outlet of the valve (21) and a second position in which the second inlet of the valve (21) is in fluid communication with the outlet of the valve (21).

10. The turbine engine according to claim 8, characterised in that the auxiliary tank (20) comprises a second inlet port (206), and in that the auxiliary supply device (14') comprises a valve (21) comprising a body (21a) having an inlet connected to the auxiliary tank (20) and a first outlet connected to the second inlet port (206) of the auxiliary tank (20), and a second outlet connected to the control system (13), the valve (21) further comprising a member movable within the body and configured to move between a first position in which the inlet of the valve (21) is in fluid communication with the first outlet of the valve (21) and a second position in which the inlet of the valve (21) is in fluid communication with the second outlet of the valve (21).

11. The turbine engine according to the preceding claim, characterised in that the inlet (18a) of the supply pump (18) is connected to the main tank (15).

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