Turbine engine module comprising an oil supply circuit

Abstract

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

Description

[0001] DESCRIPTION

[0002] TITLE: MODULE FOR A TURBOMACHINE COMPRISING AN OIL SUPPLY CIRCUIT

[0003] Technical field of the invention

[0004] The invention relates to the field of modules for aircraft turbomachines comprising a lubrication enclosure and an oil supply circuit for the lubrication enclosure.

[0005] Technical background

[0006] A turbomachine, particularly an aircraft turbomachine, generally extends along and around a longitudinal axis. It comprises a gas generator which typically comprises, 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.

[0007] The low-pressure compressor rotor is typically connected to the low-pressure turbine rotor via a low-pressure shaft. The high-pressure compressor rotor is connected to the high-pressure turbine rotor via a high-pressure shaft.

[0008] The turbomachine further comprises a fan which is located upstream of the gas generator and which is rotated about the longitudinal axis by a fan shaft. The fan shaft can be connected to the low-pressure shaft via a speed reducer.

[0009] The high and low pressure shafts are guided in rotation by means of guide bearings which must be lubricated to ensure their proper functioning. Also, the speed reducer has meshes and must also be lubricated to ensure its proper functioning. It is therefore known to spray lubricating oil onto the guide bearings and into the reducer. In order to protect the related components of the turbomachine from this lubricating oil, the guide bearings and the reducer are typically arranged in lubrication enclosures. The guide bearings located upstream of the turbomachine are located in one or more upstream lubrication enclosures, and the guide bearings located downstream of the turbomachine are arranged in one or more downstream lubrication enclosures.

[0010] In order to supply oil to the lubrication chambers of the turbomachine, the latter typically comprises an oil system. The oil system generally comprises an oil reservoir and an oil supply circuit connected to the lubrication chambers. The supply circuit comprises a pump having an oil inlet connected to the oil reservoir and an oil outlet connected to the lubrication chambers. The pump is typically driven by one of the shafts of the turbomachine, for example the high-pressure shaft or the low-pressure shaft, via an accessory gear box, also known by the English acronym AGB for "Accessory GearBox". The flow rate of the pump in the supply circuit is therefore proportional to the speed of the power shaft of the turbomachine.

[0011] Above a certain temperature, the oil circulating in the turbomachine is subject to coking risks which can damage the turbomachine oil system or the turbomachine components. Also, above a certain oil temperature, the lubrication chambers and the gears of the speed reducer can be damaged. In this context, the cooling of the oil within the turbomachine is a real challenge.

[0012] In order to reduce the oil temperature, it is known to install a heat exchanger in the supply circuit, between the lubrication chamber and the pump. 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 is subject to a backpressure that increases according to the pressure losses, requiring the pump to be oversized.Also, heat exchangers can be oversized, increasing the mass and size of the turbomachine.

[0013] Therefore, there is a need to provide a turbomachine module comprising a lubrication enclosure and a lubrication system, in which the cooling of the lubricating oil and the hydraulic performance of this system are improved.

[0014] Summary of the invention

[0015] For this purpose, the invention proposes a module for an aircraft turbomachine, the module comprising:

[0016] - at least one lubrication enclosure,

[0017] - a mechanical power shaft, and

[0018] - an oil system comprising:

[0019] - an oil tank,

[0020] - an oil supply circuit for the lubrication enclosure, this supply circuit comprising:

[0021] - a first pump driven by the power shaft and comprising an oil inlet connected to the tank and an oil outlet, and

[0022] - a first heat exchanger comprising a first oil circuit connecting the oil outlet of the first pump to the lubrication enclosure, and a second circuit of a cooling fluid. The module according to the invention is remarkable in that the oil system further comprises:

[0023] - an oil cooling circuit, this cooling circuit comprising:

[0024] - a second pump comprising an oil inlet connected to the tank and an oil outlet,

[0025] - a second heat exchanger comprising a first oil circuit connecting the oil outlet of the second pump to the reservoir, and a second circuit of a cooling fluid, and

[0026] - a second pump control member configured to regulate the flow rate of the second pump.

[0027] Thus, according to the invention, the oil system comprises a supply circuit dedicated to supplying oil to the lubrication enclosure and an oil cooling circuit dedicated to cooling the oil.

[0028] The cooling circuit is a closed circuit. The second heat exchanger connects the second pump to the tank. It thus forms a circuit separate from the supply circuit.

[0029] Thanks to this configuration, it is no longer necessary to multiply the heat exchangers or to oversize them to operate at a higher oil pressure in the supply circuit. This makes it possible in particular to limit the pressure losses in the supply circuit and therefore the back pressure of the first pump. Such advantages make it possible to limit oversizing of the first pump.

[0030] Furthermore, according to the invention, the flow rate of the second pump of the cooling circuit is controlled by the control member while the first pump is driven by the power shaft, making its flow rate proportional to the rotation speed of the power shaft.

[0031] Thanks to such a first pump and the first heat exchanger, the cooling of the oil supplying the lubrication enclosure is kept constant. Thanks to the modulated flow rate of the second pump, the flow rate of the second pump is adapted to the cooling needs of the turbomachine. For example, when oil cooling is not necessary, it is possible not to drive the second pump.

[0032] The invention may comprise one or more of the following features, taken in isolation from each other or in combination with each other:

[0033] -- the power supply and cooling circuits are independent of each other,

[0034] - the second pump is an electric pump,

[0035] - the second heat exchanger is an air / oil type exchanger and the first heat exchanger is a fuel / oil type exchanger,

[0036] - the supply circuit includes an additional heat exchanger mounted between the first heat exchanger and the lubrication enclosure,

[0037] - the additional heat exchanger is of the air / oil type,

[0038] - the cooling circuit has an air / oil exchange surface greater than at least 50% of an air / oil exchange surface of the oil system,

[0039] - the cooling circuit includes an additional heat exchanger mounted between the second heat exchanger and the tank,

[0040] - the additional heat exchanger is air / oil type,

[0041] - a hydraulic control system and a third pump comprising

[0042] - an oil inlet connected to the tank, and

[0043] - an oil outlet connected to the hydraulic control system,

[0044] - the third pump is driven by the power shaft.

[0045] Brief description of the figures Other characteristics and advantages will emerge from the following description of non-limiting embodiments of the invention with reference to the appended drawings in which:

[0046] [Fig.1] Figure 1 is a perspective view of an aircraft turbomachine to which the invention can be applied,

[0047] [Fig.2] Figure 2 is a schematic longitudinal sectional view of a gas generator equipping the turbomachine of Figure 1,

[0048] [Fig.3] Figure 3 is a schematic view of a lubrication system according to one embodiment of the invention,

[0049] [Fig.4] Figure 4 is a schematic view of a lubrication system according to another embodiment of the invention,

[0050] [Fig.5] Figure 5 is a schematic view of a lubrication system according to one embodiment of the invention.

[0051] Detailed description of the invention

[0052] An example of a turbomachine 1, in particular an aircraft turbomachine, according to the invention, is shown in FIG. 1. The turbomachine 1 is for example a bypass turbojet. The turbomachine 1 is preferably an open rotor fan. The turbomachine 1 may have any other architecture and be in the form of a turboprop, for example.

[0053] The turbomachine 1 is modular. It comprises a plurality of modules assembled together. In the remainder of the description, the terms “turbomachine module” and “turbomachine” are used interchangeably.

[0054] The turbomachine 1 extends along a longitudinal axis X. A gas flow F flows into the turbomachine 1.

[0055] For the purposes of the present invention, the terms "upstream" and "downstream" are understood relatively 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. Furthermore, the terms "longitudinal", "longitudinally", "radial", "radially" are understood relatively to the longitudinal axis X of the turbomachine 1. The terms "external", "internal" are understood relatively to the distance from the longitudinal axis X along a radial axis perpendicular to the longitudinal axis X.

[0056] The turbomachine 1 comprises, from upstream to downstream, a fan 2 and a gas generator G.

[0057] The fan 2 comprises a disk movable in rotation around the longitudinal axis X and at least a 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 movable in rotation around the longitudinal axis X.

[0058] The fan 2 may comprise 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.

[0059] The blades 2a, 2b of the first row and / or the second annular row may be of the variable pitch angle type. The blades 2a, 2b are thus movable in rotation around their elongation axes which extend radially.

[0060] According to the example of Figure 1, the fan 2 is of the unducted type. According to this example, the first and second rows of blades 2a, 2b are not surrounded by a nacelle or a fan casing.

[0061] The gas generator G is illustrated in Figure 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.

[0062] Each compressor 3, 4 comprises a compressor rotor 3a, 4a and each turbine 6, 7 comprises 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. The compressor rotor 3a of the low-pressure compressor 3 is connected to the turbine rotor 7a of the low-pressure turbine 7 by a power shaft called the 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 shaft 8 and high pressure shaft 9 are centered on the longitudinal axis X and rotatable 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 is divided into a primary air flow F1 passing through a primary vein v1 and a secondary air flow F2 passing through a secondary vein v2 surrounding the primary vein. The primary air flow F1 passes through the low pressure 3 and high pressure 4 compressors. The compressed primary air flow F1 then passes through the combustion chamber 5 in which it is mixed with a fuel. The gases resulting from the combustion thus pass through the high pressure 6 and low pressure 7 turbines. The energy of the gases is transformed by the turbine rotor 7a of the low pressure turbine 7 into mechanical energy making it possible to drive the low pressure shaft 8 in rotation 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 a speed reducer 11 for example. The speed reducer 11 is of the mechanical type. It is for example an epicyclic or planetary gear train. In a manner not illustrated, the speed reducer 11 conventionally comprises a sun gear and a crown centered on the longitudinal axis X. It further comprises satellites meshing with the sun gear and the crown. It further comprises a planet carrier.

[0067] The solar 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 crown and the planet carrier, depending on the configuration of the reducer 11, is rotationally fixed to the fan shaft 10 and forms the output of the speed reducer 11.

[0068] The speed reducer 11 allows the fan shaft 10 to be driven at a rotational speed lower than the rotational speed of the low pressure shaft 8. This allows the bypass ratio of the turbomachine 1 to be increased.

[0069] The turbomachine 1 further comprises an inter-compressor casing 12 arranged axially between the low-pressure compressor 3 and the high-pressure compressor 4. The inter-compressor casing 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 casing 13. The inlet casing 13 is arranged axially between the fan 2 and the low-pressure compressor 3. The inlet casing 13 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.

[0071] The turbomachine 1 may further comprise 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 comprise an inter-vein compartment v3 located between the primary vein v1 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 casing 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 casing 13 and the low pressure shaft 8. The fourth bearing 15d is arranged radially between the intercompressor casing 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 casing 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 casing 14 for example.

[0077] Each bearing includes, for example, a rolling bearing. The rolling 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 avoid contaminating the related components of the turbomachine 1 with oil, the bearings 15 and the speed reducer 11 are arranged in lubrication enclosures.

[0079] For this purpose, the turbomachine 1 further comprises at least one lubrication enclosure 16, in particular a first upstream enclosure 17 in which the first, second and third bearings 15a, 15b, 15c and the speed reducer 11 are arranged, a second upstream lubrication enclosure 18 in which the fourth bearing 15d is arranged and a downstream lubrication enclosure 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 enclosure 16 is annular. Each lubrication enclosure 16 is delimited externally by a fixed wall such as a casing and internally by a movable wall such as a shaft.

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

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

[0084] Furthermore, the turbomachine 1 may comprise a hydraulic control system 20. The hydraulic control system 20 is connected to at least one of the rows of blades 2a, 2b of the fan 2. The hydraulic control system 20 typically comprises a hydraulic actuator (not shown) such as a hydraulic cylinder making it possible to vary the pitch angle of the blades of at least one of the rows of blades 2a, 2b.

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

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

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

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

[0089] The first pump 25 typically comprises 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 of the mechanical type. 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 gear box, also known by the English acronym AGB for “Accessory GearBox”. Thus, the flow rate of the first pump 25 is dependent on the rotation speed of the high-pressure shaft 9.

[0091] Furthermore, the supply circuit 23 comprises a first heat exchanger 28. The first heat exchanger 28 is mounted between the first pump 25 and the lubrication enclosure 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 enclosure 16 and a second circuit of a cooling fluid. 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 cooling of the oil without the use of another cooling fluid.

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

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

[0095] According to an embodiment illustrated in Figure 4, the supply circuit 23 may further comprise an additional heat exchanger 29 mounted between the first heat exchanger 28 and the lubrication enclosure 16, in particular the first upstream lubrication enclosure 17. The second upstream lubrication enclosure 18 and the downstream lubrication enclosure 19 being 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 makes it possible to improve the cooling of the oil before it enters the lubrication enclosure 17, in particular the first upstream lubrication enclosure 17. Indeed, the cooling requirements are generally greater if the first upstream lubrication enclosure 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 may 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 member 34. The control member 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, that is to say driven in rotation by an electric motor. The control member 34 is then of the electronic type, configured to control the rotation 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 box. The control member 34 then comprises, for example, a gearbox and a clutch making it possible to control the speed and therefore the flow rate of the second pump 30, in particular if the latter is a fixed displacement volumetric pump.

[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 be of 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 used when there is a need for additional cooling. Otherwise, the second pump 30 is not driven. This also makes it possible to optimize the heating of the fuel by not overcooling the oil.

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

[0110] According to a preferred embodiment, 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. 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 comprise a third pump 36 mounted between the reservoir 22 and the hydraulic control system 20. The third pump 36 thus comprises 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 may 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 may be connected to the reservoir 22 by a second return circuit 39.

Claims

CLAIMS 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 tank (22), - a supply circuit (23) for oil in the lubrication enclosure (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 enclosure (26), and a second circuit of a cooling fluid, characterized in that the oil system (21) further comprises: - an oil cooling circuit (24), this 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 connecting the oil outlet (33) of the second pump (30) to the reservoir (22), and a second circuit of a cooling fluid, and - a control member (34) of 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 exchanger air / oil type 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) comprises an additional heat exchanger (29) mounted between the first heat exchanger (28) and the lubrication enclosure (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 of 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) comprises an additional heat exchanger (35) mounted between the second heat exchanger (31) and the tank (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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