AUXILIARY OIL SUPPLY DEVICE FOR AN AIRCRAFT TURBOMACHINE

Abstract

The invention relates to an auxiliary oil supply device (14) comprising: an auxiliary oil reservoir (20), an auxiliary pump (22) comprising an inlet (22a) connected to the auxiliary reservoir (20) and an outlet (22b), a valve (21) comprising a body (21a) having an inlet (21b) connected to the outlet (22b) of the auxiliary pump (22) and a first outlet (21c) connected to the auxiliary reservoir (20), and a second outlet (21d) intended to be connected to the control system (13), the valve (21) further comprising a movable member in the body (21a) and configured to move between a first position in which the inlet (21b) of the valve (21) is in fluid communication with the first outlet (21c) of the valve (21) and a second position in which the inlet (21b) of the valve (21) is in fluid communication with the second outlet (21d) of the valve (21). Abstract figure: 4a

Description

Title of the invention: AUXILIARY OIL SUPPLY DEVICE FOR AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The invention relates to the field of auxiliary oil supply devices for an aircraft turbomachine. Technical background

[0002] A turbomachine for an aircraft comprises, from upstream to downstream, at least a first rotor, also called a propeller rotor, such as a propeller when the turbomachine is a turboprop, or an unducted fan when the turbomachine is of the "open rotor" type or a ducted fan when the turbomachine is a turbojet, a compressor, a combustion chamber and a turbine. The rotor of the compressor is connected to the rotor of the turbine and to the first rotor by a drive shaft. A flow of air is compressed within the compressor then the compressed air is mixed with a fuel and burned within the combustion chamber. The gases formed by the combustion pass through the turbine which drives the rotor of the compressor and the propeller rotor.

[0003] The propeller or the fan of the propulsion rotor as well as the compressor rotor are equipped with blades which make it possible to exert an action on the air flow. In order to adapt the turbomachine to the flight conditions, it is known to equip the propulsion rotor or the compressor rotor with variable pitch angle blades. For this purpose, the turbomachine comprises a system for controlling the variable pitch angle blades which comprises a control unit connected to a hydraulic actuator for rotating the blades relative to a longitudinal axis of the blades according to the orientation of the air flow.

[0004] In order to supply oil to the control system and in particular the hydraulic actuator as well as other elements of the turbomachine such as bearings and reducers, the turbomachine typically comprises an oil supply system. This supply system comprises for example a main tank connected to a second supply circuit on which is mounted a pump allowing the suction of oil from the main tank and the circulation of this oil to the hydraulic actuator. The main tank typically comprises an enclosure having a lower and upper wall connected by transverse walls. The lower wall comprises an orifice connected to the pump for the suction of the oil.

[0005] Certain phases of aircraft flight disrupt the oil supply to the actuator. hydraulic. Indeed, the aircraft may experience flight phases during which the gravitational force is zero or negative. These flight phases are called in the field of the invention "Og condition" when the gravitational force is zero or "negative g condition" when the gravitational force is reversed. During such flight phases, the oil contained in the main tank is pressed against the upper wall of the tank opposite the orifice in the negative g condition or the oil and air form a suspension loaded with air bubbles in the Og condition. The pump therefore no longer sucks in oil but air or oil heavily loaded with air bubbles, which degrades the oil supply to the control system and may even cause the supply pump to stop. In all cases, the hydraulic actuator of the control system is no longer correctly supplied with oil.

[0006] Such degradation of the oil supply to the control system and in particular to the hydraulic actuator can make the setting of the blades of the propulsion rotor uncontrollable, in particular the blades of the propeller or of the unducted fan, which can lead to the blades being feathered by a safety system. This has the consequence of significantly reducing the thrust of the turbomachine and causing a loss of control of the latter, which is not acceptable.

[0007] Therefore, there is a need to provide an oil supply device that provides oil supply to the variable pitch vane control system during flight phases when the gravitational force is zero or negative. Summary of the invention

[0008] To this end, the invention proposes an auxiliary device for supplying oil to a variable pitch angle blade control system for an aircraft turbomachine, the control system being supplied with oil from a main oil reservoir under conditions of positive gravitational force experienced by the aircraft, the auxiliary device being intended to supply oil to the control system under conditions of negative or zero gravitational force experienced by the aircraft, the auxiliary device comprising:

[0009] an auxiliary oil tank,

[0010] an auxiliary pump comprising an inlet connected to the auxiliary tank and an outlet,

[0011] a valve comprising a body having an inlet connected to the outlet of the auxiliary pump and a first outlet connected to the auxiliary reservoir, and a second outlet intended to be connected to the control system, the valve further comprising a movable member in the body and configured to move between a first position in which the inlet of the valve is in fluid communication with the first valve outlet and a second position in which the valve inlet is in fluid communication with the second valve outlet.

[0012] The device according to the invention therefore makes it possible to supply the control system from the auxiliary reservoir. The auxiliary pump according to the invention is always active. When the moving member of the valve is in the first position, the turbomachine is in a so-called normal operating phase. The valve then allows the oil which is sucked in by the auxiliary pump to be redirected to the auxiliary reservoir. When the turbomachine is in a second operating phase, in particular when the gravitational force is zero (0g condition) or negative (negative g condition), then the moving member moves to the second position. The valve then makes it possible to deliver the oil sucked in by the auxiliary pump to the control system. The control system is thus supplied without interruption.Furthermore, the continuous activity of the auxiliary pump allows the control system to be supplied without delay when the turbomachine moves into the second operating phase.

[0013] The invention may comprise one or more of the following features, taken in isolation from one another or in combination with one another:

[0014] - the auxiliary pump is a fixed displacement hydraulic pump;

[0015] - the valve comprises a hydraulic actuating chamber;

[0016] - a rotary motor for driving the auxiliary pump;

[0017] - a pressure limiter arranged between the auxiliary pump and the valve.

[0018] The invention also relates to an aircraft turbomachine comprising:

[0019] variable pitch angle blades,

[0020] a blade timing control system comprising:

[0021] a control unit connected to a hydraulic actuator,

[0022] an oil supply system comprising:

[0023] a main oil tank,

[0024] an oil feed pump comprising an inlet connected to the main oil reservoir and an outlet connected to the control system.

[0025] The turbomachine is characterized in that it further comprises an auxiliary oil supply device according to any one of the preceding characteristics.

[0026] The turbomachine may comprise one or more of the following features, taken in isolation from one another or in combination with one another:

[0027] - the oil supply system comprises:

[0028] a second oil supply circuit connecting the main reservoir to the control system and on which the supply pump is mounted, the valve being mounted on said second supply circuit between the supply pump and the control system, and

[0029] an oil recovery circuit connecting the control system to the auxiliary tank;

[0030] - the movable member is configured to move to the second position when the pressure at the feed pump inlet is below a threshold pressure;

[0031] - the auxiliary tank comprises an enclosure delimiting a first internal volume of oil and having at least a first outlet port connected to the main reservoir, a second outlet port connected to the auxiliary pump, a first inlet port connected to the control system, and a second inlet port connected to the valve, the auxiliary reservoir further comprising a movable retention wall capable of equalizing the volume of oil to the internal volume when the valve is in the second position;

[0032] - the movable retention wall is formed by the enclosure and comprises a membrane retractable formed by a wall of the enclosure;

[0033] - the movable retention wall comprises a plate movable in translation in the enclosure, extending between two side walls of the enclosure.

[0034] The invention also relates to a method for supplying oil to an aircraft turbomachine according to any one of the above characteristics, comprising the following steps:

[0035] (a) during a first operating state of the turbomachine, supplying oil the control system from the main tank, the valve being in a nominal operating state in which the moving member is in the first position,

[0036] (b) detecting a second operating state of the turbomachine,

[0037] (c) actuating the valve to move the movable member from the first position to the second position to supply oil to the control system from the auxiliary tank. Brief description of the figures

[0038] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0039] [Fig-1] [Fig.l] is a schematic representation in longitudinal section of a half-turboengine for an aircraft according to a first embodiment of the invention;

[0040] [Fig.2] [Fig.2] is a schematic perspective representation of an aircraft turbomachine according to a second embodiment of the invention;

[0041] [Fig.3] [Fig.3] is a schematic representation in longitudinal section of an aircraft turbomachine according to a third embodiment of the invention;

[0042] [Fig.4a] [Fig.4a] is a schematic representation of an oil supply system comprising the auxiliary device according to the invention in a first position;

[0043] [Fig.4b] [Fig.4b] is a schematic representation of an oil supply system comprising the auxiliary device according to the invention in a second position;

[0044] [Fig.5a] [Fig.5a] is a schematic representation of an auxiliary tank according to a first embodiment;

[0045] [Fig.5b] [Fig.5b] is a schematic representation of an auxiliary tank according to a second embodiment;

[0046] [Fig.5c] [Fig.5c] is a schematic representation of an auxiliary tank according to a third embodiment;

[0047] [Fig.6] [Fig.6] is a block diagram of the method according to the invention. Detailed description of the invention

[0048] A turbomachine 1, 1 1 ” for an aircraft is shown for example in 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 air flow 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.

[0049] 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.

[0050] The low pressure 10 and high pressure 9 shafts are supported by bearings 12a. The bearings 12a are contained in a lubrication enclosure 12 for their 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 enclosure 12 is annular. The upstream and downstream bearings 120a, 120a' are arranged in the lubrication enclosure 12.

[0051] 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 makes it possible to drive the first rotor 2 at a speed lower than the rotation speed of the low pressure shaft 10. The speed reducer 11 is for example arranged in the lubrication enclosure 12 between the upstream bearing 120a and the downstream bearing 120a'.

[0052] The main air flow F passes through the turbomachine 1, 1', 1” and divides into a flow primary air Fl which passes through the engine M within a primary vein and into a secondary air flow F2 which passes through the first rotor 2 in a secondary vein surrounding the primary vein.

[0053] The turbomachine 1, 1', 1” comprises blades 2a which make it possible to exert an action on the main air flow F, primary air flow F1 or the secondary air flow F2. For example, the rotors of the low pressure compressor 3 and high pressure compressor 4 comprise blades 2a which make it possible to compress the primary air flow F1 upstream of the combustion chamber 5.

[0054] Generally, the blades 2a can be fixed in rotation around the longitudinal axis X or mobile in rotation around the longitudinal axis X or an axis parallel to the longitudinal axis X.

[0055] According to a first embodiment shown in [Fig. 1], the turbomachine 1 is a dual-flow turbojet. According to this embodiment, the first rotor 2 is a ducted fan which is arranged upstream of the engine M. The fan comprises blades 2a. The blades 2a of the fan are rotatable about the longitudinal axis X. They are for example carried by a disk centered on the longitudinal axis X and driven in rotation by the rotor shaft 100. The blades 2a are arranged inside a fan casing 2b. The casing 2b is surrounded by a nacelle (not shown).

[0056] According to a second embodiment shown in [Fig.2], the turbomachine 1' is a turbojet with an unducted fan. According to this embodiment, the first rotor 2 is a fan which comprises blades 2a. According to 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 blades 2a of the fan are carried by a disk rotatable about the longitudinal axis X. Furthermore, according to this embodiment, a rectifier 2' is optionally arranged downstream of the fan 2 in order to straighten the secondary air flow F2. The rectifier 2' forms a fixed blade around the longitudinal axis X. It comprises blades 2a which may be of variable pitch. The blades 2a are mounted outside the nacelle.

[0057] According to a third embodiment shown in [Fig. 3], the turbomachine 1” is a turboprop. According to this embodiment, the first rotor 2 is a propeller which is arranged upstream of the engine M. The propeller is rotatable about a propeller axis H parallel to the longitudinal axis X and comprises blades 2a. The blades 2a are carried by a disk centered on the propeller axis H. The blades 2a are for example at least two in number and regularly distributed on the disk.

[0058] The blades 2a extend radially relative to the longitudinal axis X. They typically comprise a blade and a fixing element to the disc. The fixing element is for example a fixing foot or a platform.

[0059] According to the invention, the blades 2a have a variable pitch angle. By variable pitch angle, it is understood that the blades 2a are movable in rotation around a transverse axis Z substantially perpendicular or perpendicular to the longitudinal axis X.

[0060] In order to control the pitch angle of the blades 2a, the turbomachine 1, 1', 1” according to the invention comprises a control system 13 for the blades 2a with variable pitch angle. 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” in English. The hydraulic actuator 13b is for example a hydraulic cylinder comprising a rod movable in translation connected to the blade 2a possibly via a movement transformation mechanism. The translational movement of the rod makes it possible to move the blade 2a in rotation around 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 is movable in rotation about the longitudinal axis X or an axis parallel to the longitudinal axis X. The hydraulic actuator 13b is for example integral in rotation with the blades 2a. The hydraulic actuator 13b is for example arranged upstream of the control unit 13a.

[0061] The control system 13 advantageously comprises 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 control unit 13a which is fixed to the hydraulic actuator 13b which is rotatable. The oil transfer device 13c is known by the acronym OTB for “Oil Transfer Bearing” in English. The oil transfer device 13c is for example arranged in the lubrication enclosure 12.

[0062] The turbomachine 1, 1', 1” further comprises an electrical control unit 24. The electrical control unit 24 makes it possible to control the control unit 13a. The electrical control unit 24 is for example a FADEC (for “Full Authority Digital Engine Control” in English). Furthermore, the turbomachine 1, 1', 1” comprises an oil supply system 140 shown for example in FIGS. 4a and 4b. The oil supply system 140 comprises a first supply circuit 14a and a second supply circuit 14b. The first supply circuit 14a supplies the lubrication enclosure 12 for the lubrication of the bearings 12a and the reduction gear 11 and the second supply circuit 14b supplies the control system 13 with oil. The oil supply system 140 advantageously comprises a recovery circuit 14a' of oil from the lubrication enclosure 12 and a recovery circuit 14b' of oil from the control system 13.

[0063] 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.

[0064] According to the invention, the oil supply system 140 further comprises a main oil reservoir 15 connected to the first supply circuit 14a and to the second supply circuit 14b.

[0065] The first supply circuit 14a comprises a first pump 16a allowing the oil to be sucked from the main tank 15 and circulated in the first supply circuit 14a. Advantageously, the first supply circuit 14a comprises a first oil / fuel exchanger 17a, and optionally a second oil / fuel exchanger 17b, which are arranged between the first pump 16a and the lubrication enclosure 12.

[0066] Advantageously, the oil supply system 140 comprises a distribution valve 19 with two outlets, mounted on the first circuit 14a. The distribution valve 1 is a variable diaphragm valve. The distribution valve 19 is mounted between the first pump 16a and the lubrication enclosure 12. Preferably, the distribution valve 19 is mounted between the first oil / fuel exchanger 17a and the second oil / fuel exchanger 17b. The first outlet of the distribution valve 19 is for example connected to the lubrication enclosure 12 and the second outlet is connected to the reducer 11.

[0067] Furthermore, according to this example, an air / oil exchanger 17c connects the second output of the distribution valve 19 and the reducer 11.

[0068] The distribution valve 19 is for example controlled by the electrical control unit 24.

[0069] The oil recovery circuit 14a' of the lubrication enclosure 12 comprises a second pump 16b connected to the lubrication enclosure 12 and to the main reservoir 15. The second pump 16b allows the oil to be sucked into the lubrication enclosure 12 and returned to the main reservoir 15 through the recovery circuit 14a'.

[0070] Furthermore, according to the invention, the oil supply system 140 comprises a pump 18 for supplying oil to the control system 13. The supply pump 18 is for example mounted on the second supply circuit 14b. The supply pump 18 is a hydraulic pump. The supply pump 18 is for example a positive displacement pump. The positive displacement pump is for example fixed displacement or variable displacement. The feed pump 18 comprises an inlet 18a connected to the main tank 15 and an outlet 18b connected to the control system 13. Advantageously, the feed pump 18 is mounted on the second circuit 14b, and its inlet 18a is connected to the first feed circuit 14a between the first pump 16a and the distribution valve 19. Preferably, the feed pump 18 is mounted between the first oil / fuel exchanger 17a and the distribution valve 19. The second feed circuit 14b may comprise a filter 26 arranged between the feed pump 18 and the control system 13.

[0071] During the first phase of operation of the turbomachine 1, 1', 1”, the first pump 16a draws oil from the main reservoir 15 and conveys the oil in the first supply circuit 14a to the lubrication enclosure 12. The distribution valve 19 distributes the oil downstream of the first pump 16a between the lubrication enclosure 12 and the reducer 11. The supply pump 18 draws oil from the first supply circuit 14a downstream of the first pump 16a and conveys the oil in the second supply circuit 14b to the control system 13.

[0072] During the second phase of operation, typically a flight in negative (or inverted) gravity, the oil is pressed into the upper part of the main tank 15 while the lower part connected to the first pump 16a is occupied by air. In the case of zero gravity, an air-oil mixture is suspended in the tank 15. The feed pump 18 is indirectly connected to the lower part of the main tank 15 since it is connected to the main circuit 14a downstream of the first pump 16a, and therefore risks sucking in air or oil heavily laden with air bubbles. This is not acceptable because the control system 13 must be supplied with oil relatively free of air bubbles so as not to compromise the operation of the control unit 13a and therefore of the hydraulic actuator 13b which controls the pitch of the blades 2a. Also, the presence of air can lead to the stopping 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.

[0073] The auxiliary supply device 14 comprises an auxiliary oil reservoir 20, an auxiliary pump 22 comprising an inlet 22a connected to the auxiliary reservoir 20 and an outlet 22b. The auxiliary pump 22 is a fixed displacement hydraulic pump. The auxiliary pump 22 is driven by the low pressure shaft 10 or the high pressure shaft 9. Alternatively, the auxiliary pump 22 is electrically driven by an electric motor.

[0074] The auxiliary supply device 14 according to the invention further comprises a valve 21.

[0075] The valve 21 is a hydraulic valve. The valve 21 is a 3 / 2 distributor, i.e. having three orifices and two positions. The valve 21 is, for example, a hydraulically controlled distributor with spring return. The valve 21 has a body 21a having an inlet 21b connected to the outlet 22b of the auxiliary pump 22 and a first outlet 21c connected to the auxiliary reservoir 20 and a second outlet 21d connected to the control system 13. The second outlet 21d is connected to the second supply circuit 14b between the supply pump 18 and the control system 13 and advantageously between the supply pump 18 and the filter 26.

[0076] The valve 21 further comprises a movable member in the body 21a configured to move between a first position in which the inlet 21b of the valve 21 is in fluid communication with the first outlet 21c of the valve 21 and a second position in which the inlet 21b of the valve 21 is in fluid communication with the second outlet 21d of the valve 21. The valve 21 comprises for example a return spring allowing the return of the movable member from the second position to the first position. It is thus understood that in the first position as illustrated in [Fig.4a], the auxiliary pump 22 sucks the oil from the auxiliary tank 20 and the oil is redirected to the auxiliary tank 20. The oil supply to the control circuit 13 is ensured by the supply pump 18 which allows the circulation of the oil in the second supply circuit 14b from the main tank 15. In the second position as illustrated in [Fig.4b], the auxiliary pump 22 draws oil from the auxiliary reservoir 20 and the oil is supplied to the control system 13.

[0077] Thus, when the turbomachine 1, 1', 1” is in the first phase of operation, in particular when the aircraft is in a so-called “normal” flight phase, therefore in a positive g condition, the valve 21 is in the first position. When the turbomachine 1, 1', 1” is in the second phase of operation, in particular when the aircraft is in a flight phase in which the gravitational force is zero (called “0g”) or negative (called “negative g”), the valve 21 is in the second position. This makes it possible to ensure the supply of oil to the control system 13 from the auxiliary tank 20 and to avoid any interruption of the supply of oil to the control system 13 under these conditions. Preferably, the auxiliary pump 22 remains active regardless of the position of the movable member of the valve 21.This makes it possible to avoid the need for priming the auxiliary pump 22 and to guarantee a rapid supply of oil to the control system 13 during the second operating phase of the turbomachine 1.1', 1”.

[0078] The valve 21 comprises a hydraulic actuation chamber connected to the inlet 18a of the feed pump 18. When the pressure at the inlet of the feed pump 18 is lower than a threshold pressure, that is to say that the turbomachine 1, 1', 1” is in the second operating phase, then the movable member is driven into the second position. Such a configuration makes it possible to simplify the control of the valve 21. The latter does not require a particular sensor since its actuation is caused by the variation in pressure at the inlet 18a of the feed pump 18.

[0079] Alternatively, the valve 21 is directly sensitive to gravitational force.

[0080] The auxiliary tank 20 is connected to the main tank 15 by a first pipe 201a. This ensures the evacuation of the oil from the auxiliary tank 20 in the first phase of operation in particular.

[0081] The auxiliary tank 20 is configured to deliver oil during the second operating phase of the turbomachine 1, 1', 1”. The auxiliary tank 20 is therefore configured to deliver oil in 0g and / or negative g conditions.

[0082] The auxiliary tank 20 comprises an enclosure 200. The enclosure 200 has a first outlet port 201 connected to the main tank 15 for example by the first pipe 201a, a second outlet port 202 connected to the auxiliary pump 22 by a second pipe 202a, a first inlet port 203 connected to the control system 13 by the oil recovery circuit 14b' of the control system 13 and a second inlet port 206 connected to the valve 21. The enclosure 200 delimits an internal volume of oil. In addition, the auxiliary tank 20 comprises a retention member 204.

[0083] According to a first embodiment shown in Figures 5a and 5b, the retention member 204 is movable. It is capable of equalizing the volume of oil to the internal volume when the valve 21 is in the second position. The movable retention member 204 defines a variable volume V1 in the internal volume. The variable volume V1 varies between a first volume which is less than or equal to the internal volume and a second volume which is equal to the volume of oil in the auxiliary tank 20. According to this first embodiment, the supply system 14 advantageously comprises a return valve 205 arranged on the first pipe 201a.

[0084] According to a first exemplary embodiment shown in [Fig.5a], the enclosure 200 has two parallel longitudinal walls 200a, 200b connected by two parallel side walls 200c, 200d. The movable retention member 204 comprises a plate movable in translation in the enclosure 200 and extending between the two longitudinal walls 200a, 200b. The movable plate may have faces parallel to the side walls 200c, 200d, and form for example a piston.

[0085] According to a second exemplary embodiment shown in [Fig.5b], the enclosure 200 is for example spherical or oblong. It comprises a wall 200' of section circular. The movable retention wall 204 is formed by the wall 200' of the enclosure 200. It comprises a retractable membrane. The retractable membrane is for example made of elastomeric material.

[0086] According to a second embodiment shown in [Fig.5c], the enclosure 200 is polygonal. It comprises an upper wall 200a' and a lower wall 200b' connected by opposite transverse walls 200c”, 200d”. The transverse walls 200c”, 200d” are parallel to each other. The upper wall 200a' comprises, for example, a first portion 200a 1” parallel to the lower wall 200b' and a second portion 200a2” inclined towards the inside of the enclosure 200 so as to define, with the first portion 200al” a vertex oriented towards the outside of the enclosure 200. The first outlet port 201 is, for example, arranged on the transverse wall 200d' ' and the first inlet port 203 is, for example, arranged on the opposite transverse wall 200c”. The second outlet port 202 is for example arranged on the upper wall 200a', for example on the second portion 200a2”. The retention member 204 is for example a baffle arranged in the enclosure 200.The baffle 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 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. The first and second end walls 204a, 204b are parallel to the transverse walls 200c”, 200d”. The baffle separates a supply volume VI' and an adjustment volume V2. The supply volume VI' is in fluid communication with the second outlet port 202 and the adjustment volume V2 is in fluid communication with the first outlet port 201.

[0087] The auxiliary tank 20 is configured to communicate oil to the second outlet port 202 continuously in the first and second operating phases of the turbomachine 1, 1', 1”. Indeed, in the first embodiment of the auxiliary tank 20, when the valve 21 is in the second position, the movable retention wall 204 moves so that the variable volume V1 is equal to the volume of oil in the enclosure 200. The movable retention wall 204 also closes the first outlet port 201. Thus, the oil contained in the first internal volume VI communicates with the second outlet port 202. The auxiliary pump 22 then sucks oil 22 free of air bubbles even in 0g or negative g conditions.

[0088] In the second embodiment of the auxiliary tank 20, the baffle makes it possible to increase the time allowed for the air, present in the adjustment volume V2, entering the enclosure 200 via the first outlet port 201, to reach the supply volume VI', so that the second orifice 202 is only in contact with oil during the second phase of operation of the turbomachine 1, 1', 1” therefore even in Og or negative g conditions. The auxiliary pump 22 then sucks oil 22 free of air bubbles even in Og or negative g conditions.

[0089] Advantageously, the auxiliary supply device 14 further comprises a pressure limiter 25 arranged at the outlet of the auxiliary pump 22, between the auxiliary pump 22 and the valve 21. The pressure limiter 25 is for example a non-return valve.

[0090] According to a preferred embodiment of the invention, the feed pump 18 comprises a non-return valve 180 so that all the oil delivered by the auxiliary pump 22 feeds the control system 13.

[0091] A method of supplying oil to the turbomachine 1, 1', 1” will now be described. The method is for example illustrated in [Fig.6].

[0092] The method comprises the following steps:

[0093] (a) during a first operating state of the turbomachine 1, 1', 1”, supply in oil the control system 13 from the main tank 15, the valve 21 being in a nominal operating state in which the movable member is in the first position,

[0094] (b) detecting a second operating state of the turbomachine 1, 1', 1”,

[0095] (c) actuate the valve 21 to move the member from the first position to the second position for supplying oil to the control system from the auxiliary tank 20.

[0096] During steps (a), (b) and (c), the auxiliary pump 22 continuously draws oil from the auxiliary reservoir 20.

[0097] Thanks to the device of the invention, it is possible to ensure a supply of the control system 13 during all the operating phases of the turbomachine 1, 1', 1” and in particular during the flight phases of the aircraft in 0g or negative g conditions. The device of the invention allows a supply of the control system 13 thanks to the auxiliary pump 22 and the valve 21. Also, the control of the valve 21 does not require a specific sensor such as an accelerometer. Indeed, it advantageously comprises a hydraulic actuation chamber directly connected to the inlet 18a of the supply pump 18. A reduction in the pressure at the inlet 18a of the pump 18 reflecting a flight condition in 0g or negative g drives the movable member into the second position.

Claims

Claims

1. Auxiliary device (14) for supplying oil to a control system (13) for variable pitch blades (2a) for an aircraft turbomachine (1, 1', 1”), the control system (13) being supplied with oil from a main oil reservoir (15) under conditions of positive gravitational force experienced by the aircraft, the auxiliary device (14) being intended to supply oil to the control system (13) under conditions of negative or zero gravitational force experienced by the aircraft, the auxiliary device (14) comprising: an auxiliary oil reservoir (20), an auxiliary pump (22) comprising an inlet (22a) connected to the auxiliary reservoir (20) and an outlet (22b), a valve (21) comprising a body (21a) having an inlet (21b) connected to the outlet (22b) of the auxiliary pump (22) and a first outlet (21c) connected to the auxiliary tank (20), and a second outlet (21d) intended to be connected to the control system (13),the valve (21) further comprising a movable member in the body (21a) and configured to move between a first position in which the inlet (21b) of the valve (21) is in fluid communication with the first outlet (21c) of the valve (21) and a second position in which the inlet (21b) of the valve (21) is in fluid communication with the second outlet (21d) of the valve (21).,

2. Device according to claim 1, characterized in that the auxiliary pump (22) is a fixed displacement hydraulic pump.

3. Device according to any one of the preceding claims, characterized in that the valve (21) comprises a hydraulic actuating chamber.

4. Device according to any one of the preceding claims, characterized in that it comprises a rotary motor for driving the auxiliary pump (22).

5. Device according to any one of the preceding claims, characterized in that it comprises a pressure limiter (25) arranged between the auxiliary pump (22) and the valve (21).

6. Aircraft turbomachine (1, 1', 1”) comprising: blades (2a) with variable pitch angle, a control system (13) for the blades (2a) comprising: a control unit (13a) connected to a hydraulic actuator (13b), an oil supply system (140) comprising: a main oil reservoir (15), an oil supply pump (18) comprising an inlet (18a) connected to the main oil reservoir (15) and an outlet (18b) connected to the control system (13), characterized in that it further comprises an auxiliary oil supply device (14) according to any one of the preceding claims.

7. Turbomachine according to the preceding claim, characterized in that the oil supply system (140) comprises: a second oil supply circuit (14b) connecting the main reservoir (15) to the control system (13), and on which the supply pump (18) is mounted, the valve (21) being mounted on said second supply circuit (14b) between the supply pump (18) and the control system (13), and an oil recovery circuit (14b') connecting the control system (13) to the auxiliary reservoir (20).

8. Turbomachine according to one of claims 6 or 7 in combination with claim 3, characterized in that the movable member is configured to move towards the second position when the pressure at the inlet (18a) of the feed pump (18) is lower than a threshold pressure.

9. Turbomachine according to any one of the preceding claims, characterized in that the auxiliary tank (20) comprises an enclosure (200) delimiting a first internal volume of oil and having at least a first outlet port (201) connected to the main tank (15), a second outlet port (202) connected to the auxiliary pump (18), a first inlet port (203) connected to the control system (13), and a second inlet port (206) connected to the valve (21), the auxiliary tank (200) further comprising a movable retention wall (204) capable of equalizing the volume of oil to the internal volume when the valve (21) is in the second position.

10. Turbomachine according to the preceding claim, characterized in that the movable retaining wall (204) is formed by the enclosure (200) and comprises a retractable membrane formed by a wall (200') of the enclosure (200).

11. Turbomachine according to claim 9, characterized in that the movable retention wall (204) comprises a plate movable in translation in the enclosure (200), extending between two side walls (200a, 200b) of the enclosure (200).

12. Method for supplying oil to an aircraft turbomachine (1, 1', 1”) according to any one of claims 6 to 11, comprising the following steps: (a) during a first operating state of the turbomachine (1, 1', 1”), supplying the control system (13) with oil from the main tank (15), the valve (21) being in a nominal operating state in which the moving member is in the first position, (b) detecting a second operating state of the turbomachine (1, 1', 1”), (c) actuating the valve (21) to move the movable member from the first position to the second position to supply oil to the control system (13) from the auxiliary reservoir (20).

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