MODULE FOR A TURBOMACHINE INCLUDING AN OIL SUPPLY CIRCUIT

Abstract

The invention relates to a module comprising: - an oil reservoir (22), - an oil supply circuit (23) comprising: - a first pump (25) comprising an oil inlet (26) connected to the reservoir (22) and an oil outlet (27), and - a first heat exchanger (28) comprising a first oil circuit and a second cooling fluid circuit, - a cooling circuit (24) comprising: - a second pump (30) comprising an oil inlet (32) connected to the reservoir (22) and an oil outlet (33), - a second heat exchanger (31) comprising a first oil circuit and a second cooling fluid circuit, and - a control element (34) for the second pump (30) configured to regulate the flow rate of the second pump (30). Illustration figure: 3

Description

Title of the invention: MODULE FOR A TURBOMACHINE COMPRISING AN OIL SUPPLY CIRCUIT Technical field of the invention

[0001] The invention relates to the field of modules for aircraft turbomachinery comprising a lubrication chamber and an oil supply circuit for the lubrication chamber. Technical background

[0002] A turbomachine, particularly an aircraft turbomachine, generally extends along and around a longitudinal axis. It comprises a gas generator which typically includes, from upstream to downstream in the direction of gas flow in the turbomachine, a low-pressure compressor, a high-pressure compressor, a gas combustion chamber, a high-pressure turbine and a low-pressure turbine.

[0003] The rotor of the low-pressure compressor is typically connected to the rotor of the low-pressure turbine via a low-pressure shaft. The rotor of the high-pressure compressor, on the other hand, is connected to the rotor of the high-pressure turbine via a high-pressure shaft.

[0004] The turbomachine further comprises a fan located upstream of the gas generator and driven in rotation about the longitudinal axis by a fan shaft. The fan shaft can be connected to the low-pressure shaft via a speed reducer.

[0005] The high and low pressure shafts are guided in rotation by means of guide bearings which must be lubricated to ensure their proper operation. Also, the speed reducer has gears and must also be lubricated to ensure its proper operation.

[0006] It is therefore known to spray lubricating oil onto the guide bearings and into the gearbox. In order to protect the associated components of the turbomachine from this lubricating oil, the guide bearings and the gearbox are typically arranged in lubrication chambers. The guide bearings located upstream of the turbomachine are located in one or more upstream lubrication chambers, and the guide bearings located downstream of the turbomachine are arranged in one or more downstream lubrication chambers.

[0007] In order to supply oil to the lubrication chambers of the turbomachine, the latter typically includes an oil system. The oil system generally comprises an oil reservoir and an oil supply circuit connected to the lubrication chambers. The supply circuit includes a pump having an inlet The pump is connected to the oil reservoir and has an oil outlet connected to the lubrication chambers. It is typically driven by one of the turbomachine's shafts, for example, the high-pressure or low-pressure shaft, via an accessory gearbox, also known as an AGB (Accessory Gearbox). The pump's flow rate in the supply circuit is therefore proportional to the turbomachine's power shaft speed.

[0008] Above a certain temperature, the oil circulating in the turbomachine is subject to coking, which can damage the turbomachine's oil system or its components. Furthermore, above a certain oil temperature, the lubrication chambers and the gears of the speed reducer can be damaged. Therefore, cooling the oil within the turbomachine is a critical issue.

[0009] In order to reduce the temperature of the oil, it is known to mount a heat exchanger in the supply circuit, between the lubrication chamber and the pump.

[0010] However, such an oil system configuration remains insufficient in certain turbomachine configurations. Indeed, the greater the number of lubrication chambers, the greater the cooling requirement. The tendency would therefore be to increase the number of heat exchangers in the supply circuit, between the pump and the lubrication chambers. However, the greater the number of heat exchangers, the greater the pressure losses in the supply circuit. These pressure losses directly impact the operation of the pump, which experiences back pressure that increases with the pressure losses, thus requiring the pump to be oversized. Therefore, the heat exchangers can be oversized, increasing the mass and overall size of the turbomachine.

[0011] Therefore, there is a need to provide a turbomachine module comprising a lubrication chamber and a lubrication system, in which the cooling of the lubricating oil and the hydraulic performance of this system are improved. Summary of the invention

[0012] To this end, the invention proposes a module for an aircraft turbomachine, the module comprising:

[0013] - at least one lubrication chamber,

[0014] - a mechanical power shaft, and

[0015] - an oil system comprising:

[0016] - an oil reservoir,

[0017] - an oil supply circuit for the lubrication chamber, this circuit power supply including:

[0018] - a first pump driven by the power shaft and comprising an inlet oil connected to the reservoir and an oil outlet, and

[0019] - a first heat exchanger comprising a first oil circuit connecting the oil outlet from the first pump to the lubrication chamber, and a second circuit of a cooling fluid.

[0020] The module according to the invention is remarkable in that the oil system further comprises:

[0021] - an oil cooling circuit, this cooling circuit comprising:

[0022] - a second pump comprising an oil inlet connected to the reservoir and an outlet of oil,

[0023] - a second heat exchanger comprising a first oil circuit connecting the oil outlet from the second pump to the reservoir, and a second circuit for a cooling fluid, and

[0024] - a control element for the second pump configured to regulate the flow rate of the second pump.

[0025] Thus, according to the invention, the oil system includes a supply circuit dedicated to supplying oil to the lubrication chamber and an oil cooling circuit dedicated to cooling the oil.

[0026] The cooling circuit is a closed circuit. Indeed, the second heat exchanger connects the second pump to the reservoir. It thus forms a circuit separate from the supply circuit.

[0027] Thanks to this configuration, it is no longer necessary to increase the number of heat exchangers or to oversize them to operate at a higher oil pressure in the supply circuit. This notably reduces pressure losses in the supply circuit and therefore the back pressure on the first pump. Such advantages make it possible to limit the oversizing of the first pump.

[0028] Furthermore, according to the invention, the flow rate of the second pump in the cooling circuit is controlled by the control element while the first pump is driven by the power shaft, making its flow rate proportional to the rotational speed of the power shaft.

[0029] Thanks to such a first pump and the first heat exchanger, the cooling of the oil supplying the lubrication chamber is kept constant.

[0030] Thanks to the modulated flow rate of the second pump, the flow rate of the second pump is adapted to the cooling requirements of the turbomachine. For example, when oil cooling is not required, it is possible to not drive the second pump.

[0031] The invention may comprise one or more of the following features, taken individually or in combination with each other:

[0032] — the power supply and cooling circuits are independent of each other,

[0033] - the second pump is an electric pump,

[0034] - the second heat exchanger is an air / oil type exchanger and the first The heat exchanger is a fuel / oil type exchanger.

[0035] - the supply circuit includes an additional heat exchanger mounted between the first heat exchanger and the lubrication chamber,

[0036] - the additional heat exchanger is of the air / oil type,

[0037] - the cooling circuit has an air / oil exchange surface area greater than at least 50% of the air / oil exchange surface area of ​​the oil system,

[0038] - the cooling circuit includes an additional heat exchanger mounted between the second heat exchanger and the reservoir,

[0039] - the additional heat exchanger is of the air / oil type,

[0040] - a hydraulic control system and a third pump comprising:

[0041] - an oil inlet connected to the reservoir, and

[0042] - an oil outlet connected to the hydraulic control system,

[0043] - the third pump is driven by the power shaft. Brief description of the figures

[0044] Other features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings in which:

[0045] [Fig-1] [Fig.1] is a perspective view of an aircraft turbomachine to which the invention can be applied,

[0046] [Fig.2] [Fig.2] is a schematic longitudinal cross-sectional view of a generator of gas equipping the turbomachine of [Fig.1],

[0047] [Fig.3] [Fig.3] is a schematic view of a lubrication system according to one embodiment of the invention,

[0048] [Fig.4] [Fig.4] is a schematic view of a lubrication system according to a another embodiment of the invention,

[0049] [Fig.5] [Fig.5] is a schematic view of a lubrication system according to an embodiment of the invention. Detailed description of the invention

[0050] An example of a turbomachine 1, particularly an aircraft turbomachine according to the invention, is shown in [Fig. 1]. The turbomachine 1 is, for example, a turbofan engine. The turbomachine 1 is preferably an open-rotor, unducted fan type. The turbomachine 1 may have any other architecture and may, for example, take the form of a turboprop engine.

[0051] The turbomachine 1 is modular. It comprises a plurality of modules assembled together. In the following description, the terms "turbomachine module" and "turbomachine" are used interchangeably.

[0052] The turbomachine 1 extends along a longitudinal axis X. A gas flow F flows into the turbomachine 1.

[0053] For the purposes of the present invention, the terms "upstream" and "downstream" are understood in relation to the direction of flow of the gas flow F in the turbomachine 1. The gas flow F flows in particular from left to right in Figures 1 and 2.

[0054] Furthermore, the terms "longitudinal", "longitudinally", "radial", "Radially" is understood in relation to the longitudinal axis X of the turbomachine 1. The terms "outside", "inside" are understood in relation to the distance from the longitudinal axis X along a radial axis perpendicular to the longitudinal axis X.

[0055] The turbomachine 1 comprises, from upstream to downstream, a blower 2 and a gas generator G.

[0056] The blower 2 comprises a movable disc rotating about the longitudinal axis X and at least one first annular row of blades 2a carried by the disk and regularly distributed around the longitudinal axis X. The first row of blades 2a is mobile in rotation around the longitudinal axis X.

[0057] The blower 2 may include a second annular row of blades 2b located downstream of the first row. The second row of blades 2b is preferably fixed in rotation about the longitudinal axis X.

[0058] The annular blades 2a, 2b of the first and / or second row can be of the variable pitch angle type. The blades 2a, 2b are thus free to rotate about their radially extending axes of elongation.

[0059] According to the example in [Fig. 1], the fan 2 is of the unshod type. According to this example, the first and second rows of blades 2a, 2b are not surrounded by a nacelle or a fan casing.

[0060] The gas generator G is illustrated in [Fig.2]. The gas generator G comprises, from upstream to downstream, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6 and a low-pressure turbine 7.

[0061] Each compressor 3,4 comprises a compressor rotor 3a, 4a and each turbine 6, 7 includes a turbine rotor 6a, 7a. The compressor rotors 3a, 4a and turbine rotors 6a, 7a are composed of a plurality of stages, each comprising a bladed wheel.

[0062] The compressor rotor 3a of the low-pressure compressor 3 is connected to the rotor of turbine 7a of the low pressure turbine 7 by a power shaft called low pressure shaft 8. They form a low pressure body.

[0063] The compressor rotor 4a of the high-pressure compressor 4 is connected to the turbine rotor 6a of the high-pressure turbine 6 by a power shaft called the high-pressure shaft 9. They form a high-pressure body.

[0064] The low pressure shafts 8 and high pressure shafts 9 are centered on the longitudinal axis X and are free to rotate about the longitudinal axis X. The high pressure shaft 9 is arranged coaxially around the low pressure shaft 8.

[0065] The gas flow F passes through the blower 2 and splits into a primary air flow Fl passing through a primary stream v1 and a secondary air flow F2 passing through a secondary stream v2 surrounding the primary stream. The primary air flow Fl passes through the low-pressure compressor 3 and the high-pressure compressor 4. The compressed primary air flow Fl then passes through the combustion chamber 5 where it is mixed with fuel. The combustion gases thus pass through the high-pressure turbine 6 and the low-pressure turbine 7. The energy of the gases is transformed by the turbine rotor 7a of the low-pressure turbine 7 into mechanical energy, which drives the low-pressure shaft 8 and, consequently, the low-pressure compressor 3.

[0066] Advantageously, the first annular row of blades 2a is driven in rotation by a fan shaft 10 which is connected to the low-pressure shaft 8 via, for example, a speed reducer 11. The speed reducer 11 is of the mechanical type. It is, for example, an epicyclic or planetary gear train. Not shown here, the speed reducer 11 conventionally comprises a sun gear and a ring gear centered on the longitudinal axis X. It further comprises satellite gears meshing with the sun gear and the ring gear. It also comprises a satellite carrier s.

[0067] The solar element is rotationally fixed to the low-pressure shaft 8 and forms the input of the speed reducer 11, while one or the other of the ring and the satellite carrier, depending on the configuration of the reducer 11, is rotationally fixed to the blower shaft 10 and forms the output of the speed reducer 11.

[0068] The speed reducer 11 allows the blower shaft 10 to be driven at a rotational speed lower than the rotational speed of the low-pressure shaft 8. This makes it possible to increase the dilution ratio of the turbomachine 1.

[0069] The turbomachine 1 further comprises an inter-compressor housing 12 arranged axially between the low-pressure compressor 3 and the high-pressure compressor 4. The inter-compressor housing 12 comprises, for example, an inner shell and an outer shell which are centered on the longitudinal axis X. The inner and outer shells are, for example, connected by arms.

[0070] The turbomachine 1 may further comprise an inlet housing 13. The inlet housing 13 is arranged axially between the fan 2 and the low-pressure compressor 3. The The inlet housing 13 includes, for example, an inner ferrule and an outer ferrule which are centered on the longitudinal axis X. The inner and outer ferrules are, for example, connected by arms.

[0071] The turbomachine 1 may further include an inter-turbine casing 14. The inter-turbine casing 14 is arranged axially between the high-pressure turbine 6 and the low-pressure turbine 7.

[0072] The turbomachine 1 may further include an inter-vein compartment v3 located between the primary vein vl and the secondary vein v2.

[0073] The turbomachine 1 comprises at least one bearing 15. In particular, the fan shaft 10 is guided in rotation by a first bearing 15a and advantageously a second bearing 15b. The first and second bearings 15a, 15b are arranged radially between the fan shaft 10 and the inlet housing 13.

[0074] The low-pressure shaft 8 is guided in rotation by at least a third and a fourth bearing 15c, 15d. The third bearing 15c is arranged radially between the inlet housing 13 and the low-pressure shaft 8. The fourth bearing 15d is arranged radially between the inter-compressor housing 12 and the low-pressure shaft 8.

[0075] The high-pressure shaft 9 is guided in rotation by a fifth bearing 15e. The fifth bearing 15e is, for example, arranged radially between the high-pressure shaft 9 and the inter-turbine housing 14.

[0076] The low-pressure shaft 8 can be guided in rotation downstream by a sixth bearing 15f arranged radially between a downstream end of the low-pressure shaft 8 and the inter-turbine housing 14 for example.

[0077] Each bearing unit includes, for example, a bearing. The bearing is, for example, at least one row of balls or rollers.

[0078] The bearings 15 and the speed reducer 11 are lubricated with oil to ensure their proper operation. To prevent contamination of the associated components of the turbomachine 1 by the oil, the bearings 15 and the speed reducer 11 are arranged in lubrication chambers.

[0079] For this purpose, the turbomachine 1 further comprises at least one lubrication chamber 16, in particular a first upstream chamber 17 in which the first, second and third bearings 15a, 15b, 15c and the speed reducer 11 are arranged, a second upstream lubrication chamber 18 in which the fourth bearing 15d is arranged and a downstream lubrication chamber 19 in which the fifth and sixth bearings 15e, 15f are arranged.

[0080] Depending on the configuration of the turbomachine 1, the number of bearings 15 and lubrication chambers 16 may vary.

[0081] Each lubrication chamber 16 is annular. Each lubrication chamber 16 is delimited externally by a fixed wall such as a housing and internally through a moving barrier such as a tree.

[0082] For example, the first upstream lubrication chamber 17 is located in the inner shell of the inlet housing 13 and is internally delimited by the blower shaft 10. The second upstream lubrication chamber 18 is located in the inner shell of the inter-compressor housing 12 and is internally delimited by the low-pressure shaft 8 and the downstream lubrication chamber 19 is located in the inner shell of the inter-turbine housing 14 and is internally delimited by the high-pressure shaft 9.

[0083] The fixed and movable walls delimit between them a lubrication space in which is located one or more bearings 15 and / or the speed reducer 11.

[0084] In addition, the turbomachine 1 may include a hydraulic control system 20. The hydraulic control system 20 is connected to at least one of the blade rows 2a, 2b of the blower 2. The hydraulic control system 20 typically includes a hydraulic actuator (not shown) such as a hydraulic cylinder allowing the pitch angle of the blades of at least one of the blade rows 2a, 2b to be varied.

[0085] With reference to figures 3, 4 and 5, in order to supply oil to the lubrication chamber or lubrication chambers 16 and advantageously the hydraulic control system 20, the turbomachine 1 includes an oil system 21.

[0086] The oil system 21 includes an oil reservoir 22, an oil supply circuit 23 to at least one lubrication chamber 16 and an oil cooling circuit 24.

[0087] The supply and cooling circuits 23, 24 are independent. Thus, the supply and cooling circuits 23, 24 are not connected by hydraulic lines and their operation is independent of each other.

[0088] The supply circuit 23 can be connected to a lubrication chamber 16 or to a plurality of lubrication chambers 16. Preferably, the supply circuit 23 is connected to the first and second upstream and downstream lubrication chambers 17, 18, 19. The supply circuit 23 includes at least one first pump 25 which is mounted between the reservoir 22 and the lubrication chamber 16.

[0089] The first pump 25 typically includes an oil inlet 26 and an oil outlet 27. The oil inlet 26 is connected to the reservoir 22.

[0090] The first pump 25 is mechanically driven. It is driven by one of the power shafts 8, 9 of the turbomachine 1. Typically, the first pump 25 is driven by the high-pressure shaft 9. For example, the first pump 25 is mechanically connected to the high-pressure shaft 9 via an accessory gearbox, also known by the acronym AGB for "Accessory GearBox". Thus, the flow rate of the first pump 25 is dependent on the rotational speed of the high-pressure shaft 9.

[0091] In addition, the supply circuit 23 includes a first heat exchanger 28. The first heat exchanger 28 is mounted between the first pump 25 and the lubrication chamber 16. The first heat exchanger 28 is preferably of the fuel / oil type.

[0092] The first heat exchanger 28 typically comprises a first oil circuit connecting the outlet 27 of the first pump 25 to the lubrication chamber 16 and a second cooling fluid circuit. The cooling fluid is preferably a fuel. The fuel may, in particular, be kerosene used in the combustion chamber 5. Indeed, the fuel is a cold source of fluid and thus allows the oil to be cooled without the use of another cooling fluid.

[0093] Furthermore, thanks to the first pump 25 driven by the power shaft 8, 9, the oil cooling is ensured continuously.

[0094] Also, the fuel is heated in return which helps to prevent icing of certain turbomachine equipment, such as servovalves.

[0095] According to an embodiment illustrated in [Fig.4], the supply circuit 23 may further include an additional heat exchanger 29 mounted between the first heat exchanger 28 and the lubrication chamber 16, in particular the first upstream lubrication chamber 17. The second upstream lubrication chamber 18 and the downstream lubrication chamber 19 are connected to the first pump 28 via the first heat exchanger 28.

[0096] The additional heat exchanger 29 is advantageously of the air / oil type. The cooling fluid is therefore air. This additional heat exchanger 29 improves the cooling of the oil before it enters the lubrication chamber 17, in particular the first upstream lubrication chamber 17. Indeed, the cooling requirements are generally greater if the first upstream lubrication chamber 17 houses a speed reducer, for example the speed reducer 11 described in relation to [Fig.2].

[0097] In order to minimize oil losses, the lubrication enclosure or enclosures 16 can be connected to the reservoir 22 by a first oil return circuit 23'.

[0098] According to the invention, the cooling circuit 24 comprises a second pump 30 and a second heat exchanger 31.

[0099] The second pump 30 has an oil inlet 32 ​​connected to the reservoir 22 and an oil outlet 33.

[0100] The second pump 30 has a flow rate controlled by a control element 34. The control element 34 is configured to regulate or adjust the flow rate of the second pump 30 according to the needs of the turbomachine 1.

[0101] The second pump 30 is particularly preferably electric, i.e., driven in rotation by an electric motor. The control unit 34 is then of the electronic type, configured to control the rotational speed of the electric motor driving the second pump 30.

[0102] The second pump 30 could be mechanical. According to this example, the second pump 30 is driven by the power shaft 8, 9, such as the low-pressure or high-pressure shaft 8, 9, via the accessory drive gearbox. The control unit 34 then includes, for example, a gearbox and a clutch for controlling the speed and therefore the flow rate of the second pump 30, particularly if it is a positive displacement pump with a fixed displacement.

[0103] Alternatively, and still in the case of a second mechanical pump 30 driven by the power shaft 8, 9, the second pump 30 could have variable displacement and the control member 34 would then be configured to act on the displacement and therefore on the flow rate of the second pump 30 for a stabilized drive speed of the second pump 30.

[0104] According to another example, the second pump 30 could be pneumatically driven.

[0105] The second heat exchanger 31 is mounted between the second pump 30 and the reservoir 22. The second heat exchanger 31 comprises a first oil circuit connecting the outlet 33 of the second pump 30 to the reservoir 22 and a second circuit of a cooling fluid.

[0106] Preferably, the second heat exchanger 31 is of the air / oil type. The cooling fluid is therefore air.

[0107] Thanks to the independence of the supply and cooling circuits 23, 24, it is no longer necessary to multiply the heat exchangers or to oversize the first heat exchanger 28 in the supply circuit 23. This makes it possible in particular to limit the pressure losses in the supply circuit 23 and therefore the back pressure of the first pump 25. Such advantages make it possible to limit the oversizing of the first pump 25.

[0108] Thanks to the second pump 30 with regulated flow, the second heat exchanger 31 is only activated when additional cooling is required. Otherwise, the second pump 30 is not driven. This also optimizes fuel heating by preventing oil overcooling.

[0109] According to an embodiment illustrated in figures 3 and 4, the cooling circuit 24 may include an additional heat exchanger 35 mounted between the second heat exchanger 31 and the reservoir 22. The additional heat exchanger 35 is preferably of the air / oil type.

[0110] According to a preferred embodiment, the cooling circuit 24 has a air / oil exchange surface greater than at least 50% of an air / oil exchange surface of the oil system 21. Thus, the air / oil exchange surface in the cooling circuit 24 is greater than the air / oil exchange surface in the supply circuit 23.

[0111] According to an embodiment illustrated in [Fig.5], the oil system 21 may include a third pump 36 mounted between the reservoir 22 and the hydraulic control system 20. The third pump 36 thus includes an oil inlet 37 connected to the reservoir 22 and an oil outlet 38 connected to the hydraulic control system 20.

[0112] The third pump 36 can be of the mechanical type. It is, for example, driven by the power shaft 8, 9 such as the low pressure or high pressure shaft 8, 9.

[0113] In order to minimize oil losses, the hydraulic control system 20 can be connected to the reservoir 22 by a second return circuit 39.

Claims

Demands

1. Module for an aircraft turbomachine (1), the module comprising: - at least one lubrication chamber (16), - a mechanical power shaft (8, 9), and - an oil system (21) comprising: - an oil reservoir (22), - an oil supply circuit (23) for the lubrication chamber (16), this supply circuit (23) comprising: - a first pump (25) driven by the power shaft (8, 9) and comprising an oil inlet (26) connected to the reservoir (22) and an oil outlet (27), and - a first heat exchanger (28) comprising a first oil circuit connecting the oil outlet (27) of the first pump (25) to the lubrication chamber (26), and a second circuit for a cooling fluid, characterized in that the oil system (21) further comprises: - a cooling circuit (24) oil,This cooling circuit (24) comprises: - a second pump (30) including an oil inlet (32) connected to the reservoir (22) and an oil outlet (33), - a second heat exchanger (31) including a first oil circuit connecting the oil outlet (33) of the second pump (30) to the reservoir (22), and a second circuit for a cooling fluid, and - a control device (34) for the second pump (30) configured to regulate the flow rate of the second pump (30).

2. Module according to the preceding claim, characterized in that the second pump (30) is an electric pump.

3. Module according to any one of the preceding claims, characterized in that the second heat exchanger (31) is an air / oil type exchanger and the first heat exchanger (28) is a fuel / oil type exchanger.

4. Module according to any one of the preceding claims, characterized in that the supply circuit (23) includes an additional heat exchanger (29) mounted between the first heat exchanger (28) and the lubrication chamber (16).

5. Module according to the preceding claim, characterized in that the additional heat exchanger (29) is of the air / oil type.

6. Module according to all claims 3 and 5, characterized in that the cooling circuit (24) has an air / oil exchange surface greater than at least 50% of an air / oil exchange surface of the oil system (21).

7. Module according to any one of the preceding claims, characterized in that the cooling circuit (24) includes an additional heat exchanger (35) mounted between the second heat exchanger (31) and the reservoir (22).

8. Module according to the preceding claim, characterized in that the additional heat exchanger (35) is of the air / oil type.

9. Module according to any one of the preceding claims, characterized in that it comprises a hydraulic control system (20), and in that the oil system (21) further comprises a third pump (36) comprising: - an oil inlet (37) connected to the reservoir (22), and - an oil outlet (38) connected to the hydraulic control system (20).

10. Module according to the preceding claim, characterized in that the third pump (36) is driven by the power shaft (8, 9).

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