Turbine engine comprising an accessory drive, a lubrication unit and an oil tank

Abstract

The invention relates to a turbine engine (1) comprising: - a casing (4', 12); an accessory drive (20) suspended from, and connected to, the casing (4', 12) comprising a housing (22), which defines an internal cavity, and a gear train arranged in the internal cavity; - a lubrication unit (26) comprising an equipment housing (28) fixed and attached to the housing (22), at least one pump (29) located in the equipment housing (28), which comprises a rotor coupled to the gear train, and an oil inlet (31) connected to the pump (29); and - an oil tank (27) comprising an oil outlet (34) connected to the oil inlet (31) of the lubrication unit (26), characterised in that the tank (27) is directly attached to the equipment housing (28) and is placed above the lubrication unit (26) so that the oil flows into the lubrication unit (26) under the effect of gravity.

Description

[0001] DESCRIPTION

[0002] TITLE: TURBOMACHINE COMPRISING AN ACCESSORY DRIVE BOX, A LUBRICATION UNIT AND AN OIL TANK

[0003] Technical field of the invention

[0004] The invention relates to the field of aircraft turbomachines.

[0005] The invention relates in particular to the field of turbomachines comprising an accessory drive box, a lubrication unit and an oil reservoir.

[0006] Technical background

[0007] The state of the art is illustrated by documents US-A1 -2012 / 0159966 and US-A1 -2018 / 0195413.

[0008] An aircraft turbomachine generally extends along and around a longitudinal axis. It comprises, from upstream to downstream, in the direction of gas flow in the turbomachine, a fan, a low-pressure compressor, a high-pressure compressor, a gas combustion chamber, a high-pressure turbine, and a low-pressure turbine.

[0009] The turbomachine typically comprises an engine compartment delimited radially by engine casings surrounding the compressors, the combustion chamber and the turbines.

[0010] In the ducted fan turbomachine configurations, the turbomachine further comprises a fan compartment radially delimited by a fan casing surrounding the fan. In the unducted fan turbomachine configurations, the turbomachine does not comprise a fan casing and therefore a fan compartment.

[0011] Furthermore, 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. The shafts are guided in rotation by guide bearings, which must be lubricated to ensure their proper operation.

[0012] It is therefore known to spray lubricating oil onto the guide bearings. In order to protect the associated parts of the turbomachine from this lubricating oil, the guide bearings are typically arranged in lubrication enclosures.

[0013] For the purpose of lubricating the bearings of the lubrication chambers, the turbomachine typically comprises an oil circuit. The oil circuit is typically a closed circuit which comprises a bearing lubrication circuit and possibly a circuit for recovering oil from the lubrication chambers. The oil circuit typically comprises a lubrication unit connected to an oil reservoir by oil inlet pipes and possibly oil return pipes. The lubrication unit comprises at least one feed pump which allows the oil to be drawn from the reservoir and distributed to the lubrication chambers through the feed circuit. The lubrication unit typically comprises an equipment housing in which at least one rotor of the feed pump is arranged, and at least one oil inlet of the pump connected to the reservoir by the inlet pipe.

[0014] In order to drive the rotor of the feed pump of the lubrication unit, it is known to attach and fix the lubrication unit to an accessory gearbox, better known by the English acronym AGB for "Accessory Gearbox". The accessory gearbox allows mechanical power originating from the turbomachine to be transmitted to the accessories of the turbomachine such as the pump of the lubrication unit. The accessory gearbox typically comprises a housing comprising an upstream face and a downstream face defining between them an internal cavity in which is arranged a gear train having a series of pinions meshing with each other. The casing of the lubrication unit is fixed on one of the faces of the gearbox and the rotor of the feed pump is coupled in rotation to one of the pinions of the gear train.

[0015] In ducted fan turbomachine configurations, the reservoir and the accessory drive box carrying the lubrication unit are typically located in the fan compartment. The oil reservoir is fixed outside the fan casing, on a first portion of the fan casing, while the accessory drive box carrying the lubrication unit is suspended outside the fan casing at a lower portion than the first portion on which the oil reservoir is fixed.

[0016] However, such a configuration is not suitable for turbomachines with unducted fans which do not include a fan compartment and therefore a fan casing. It was therefore considered to move the oil tank and the accessory drive box carrying the lubrication unit into the engine compartment and to fix the oil tank to one of the engine casings and to suspend the accessory drive box from this same engine casing.

[0017] However, given the size of the tank and the small diameter of the engine casing compared to the diameter of the fan casing, it is not easy to arrange both the tank and the accessory drive box carrying the lubrication unit in the engine compartment. Indeed, for lubrication needs in all circumstances, particularly in conditions of zero gravity (0g) or negative gravity (negative g), or even during a high angle of attack of the aircraft, a major part of the volume of the tank is located in the upper part of the engine compartment, that is to say the upper half extending between 9 o'clock and 3 o'clock in the azimuthal position. The tank thus has a high tangential height.However, considering the small diameter of the engine casing on the one hand, and on the other hand, that the lower part of the engine compartment is occupied by the accessory drive box while the upper part is occupied by thrust recovery rods for example, the engine compartment does not have sufficient space to accommodate such a tank. This space is all the more insufficient since it is necessary to provide a distance between the tank and the lubrication unit to accommodate and mount the inlet pipe connecting the tank to the lubrication unit. This problem is further complicated by the need to ensure the flexibility of the inlet pipe which connects the lubrication unit which is subject to movements imposed by the accessory drive box and the tank which is conversely rigidly fixed to the engine casing given its size.

[0018] In this context, there is a need to provide a turbomachine comprising an accessory drive box, a lubrication unit and an oil reservoir, the overall size of which is reduced to allow and facilitate the integration of this unit into turbomachines with either a shrouded or unshrouded fan.

[0019] Summary of the invention

[0020] To this end, the invention proposes a turbomachine for an aircraft, the turbomachine having a longitudinal axis and comprising:

[0021] - an annular casing centered on the longitudinal axis,

[0022] - an accessory drive box which is located outside the housing and which is suspended from the housing, the accessory drive box being connected to the housing and comprising: a housing defining an internal cavity, and a gear train arranged in the internal cavity,

[0023] - a lubrication group comprising: an equipment housing attached and fixed to the housing of the accessory drive box, at least one pump located in the equipment housing and comprising a rotor coupled to the gear train, and an oil inlet connected to the pump, and - an oil reservoir comprising an oil outlet connected to the oil inlet of the lubrication group.

[0024] The turbomachine is remarkable in that the reservoir is directly attached to the equipment housing and is placed above the lubrication unit so that the oil flows by gravity into the lubrication unit.

[0025] According to the invention, the reservoir is directly attached to the equipment housing of the lubrication unit. Such a feature makes it possible to dispense with pipes for connecting the oil outlet of the reservoir to the oil inlet of the lubrication unit. Without such pipes, the radial or angular space around the casing between the reservoir and the lubrication unit is considerably reduced or even eliminated, making it possible to reduce the overall size of the assembly. It is therefore possible to place the assembly formed by these two elements in a cramped engine compartment of the turbomachine, typically around the high-pressure compressor casing or the intermediate casing which has a diameter smaller than the diameter of the fan casing and therefore less available space to accommodate the assembly.

[0026] Thanks to the invention, it is therefore possible to arrange the reservoir and the lubrication unit both in turbomachines with unducted fans and in turbomachines with ducted fans.

[0027] In addition, the number of interfaces is reduced, which simplifies the installation, maintenance, and disassembly of the turbomachine. The mass of the assembly is also significantly reduced.

[0028] Furthermore, the reservoir is positioned above the lubrication unit. Thanks to such a configuration, the oil flows by gravity to the lubrication unit, without the formation of air bubbles. The pump of the lubrication unit does not suck in any air, which makes it possible to maintain adequate pressure in the lubrication circuit to which the lubrication unit is connected. The invention may comprise one or more of the following features, taken in isolation from each other or in combination with each other:

[0029] - the reservoir extends angularly around the longitudinal axis between a first end located at an angular position between 12 o'clock and 2 o'clock and an opposite end located at an angular position between 3 o'clock and 4 o'clock;

[0030] - the housing of the accessory drive box extends angularly around the longitudinal axis between a first circumferential end located at an angular position between 9 o'clock and 7 o'clock and a second circumferential end located at an angular position between 3 o'clock and 5 o'clock;

[0031] - the housing comprises an upstream face and a downstream face extending between the first and second circumferential ends, the equipment housing being attached and fixed to the downstream face, at the second circumferential end;

[0032] - radial suspension arms connecting the accessory drive box to the housing;

[0033] - connecting arms connecting the accessory drive box to the tank;

[0034] - a support arranged radially between the casing and the tank and extending over an angular sector around the casing, and

[0035] - at least one connecting arm connecting the support to the casing, the support being fixed to the tank and to the accessory drive box;

[0036] - support is fixed to the accessory drive box by bolting;

[0037] - the support has a first end fixed to the tank and an opposite end fixed at the second circumferential end of the drive box;

[0038] - at least one connecting arm connecting the tank to the casing;

[0039] - the tank is fixed to the equipment box by bolting; - the equipment box is fixed to the accessory drive box housing by welding, bolting or flanges;

[0040] - from upstream to downstream:

[0041] - a blower,

[0042] - a low pressure compressor,

[0043] - a high pressure compressor,

[0044] - a high pressure turbine mechanically connected to the high pressure compressor, and

[0045] - a low pressure turbine mechanically connected to the low pressure compressor, the casing being located around the high pressure compressor or arranged axially between the low pressure and high pressure compressors.

[0046] Brief description of the figures

[0047] 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: Figure 1 is a longitudinal sectional view of an example of an aircraft turbomachine according to the invention; Figure 2 is a schematic perspective view of the gas generator of the turbomachine of Figure 1, Figure 3 is a schematic perspective view of an accessory drive box equipping the turbomachine of the invention, Figure 4 is a schematic view of an oil circuit comprising a lubrication circuit and an oil recovery circuit, Figure 5 is a schematic perspective view of a lubrication unit equipping the turbomachine of the invention, Figure 6 is a schematic perspective view of an oil reservoir equipping the turbomachine of the invention,Figure 7 is a perspective view of a part of the turbomachine illustrating the attachment of the tank to the turbomachine according to a first embodiment of the invention, Figure 8 is a cross-sectional view of the turbomachine illustrating the attachment of the tank to the turbomachine according to a second embodiment of the invention, Figure 9 is a cross-sectional view of the turbomachine illustrating the attachment of the tank to the turbomachine according to a third embodiment of the invention.,

[0048] Detailed description of the invention

[0049] An example of an aircraft turbomachine 1 according to the invention is shown very briefly in Figures 1 and 2. The turbomachine 1 is for example a turbojet.

[0050] The turbomachine 1 extends along a longitudinal axis X. An air flow F flows into the turbomachine 1.

[0051] For the purposes of the present invention, the terms "upstream" and "downstream" are understood to mean relative to the direction of flow of the air flow F in the turbomachine 1 along the longitudinal axis X.

[0052] The terms "longitudinal", "longitudinally", are understood in relation to the longitudinal axis X of the turbomachine 1. The terms "radial", "radially" are understood in relation to a radial axis perpendicular to the longitudinal axis X. The terms "external", "internal" are understood relatively in relation to the distance from the longitudinal axis X along the radial axis perpendicular to the longitudinal axis X.

[0053] The terms "below" and "above" are understood to refer to a nominal position of the turbomachine 1.

[0054] The angular positions expressed in hours are measured around the longitudinal axis X in the nominal position of the turbomachine 1, and understood by analogy to the corresponding position of the hands on the dial of a clock when looking from the front (upstream) of the turbomachine 1. The nominal operating position of the turbomachine 1 is a position in which the longitudinal axis X is perpendicular to the direction of gravity and in which the turbomachine 1 is in the mounting position on the aircraft.

[0055] So, typically, in nominal position, the aircraft wing is positioned at 12 o'clock.

[0056] The term “casing” designates in the invention an annular and structural element of the turbomachine 1 which is fixed.

[0057] The turbomachine 1 comprises, from upstream to downstream, a fan 2 and a gas generator comprising 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.

[0058] 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.

[0059] 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 low-pressure shaft 8. They form a low-pressure body.

[0060] 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 high-pressure shaft 9. They form a high-pressure body.

[0061] 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.

[0062] The air 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 which is injected into the combustion chamber 5 via feed injectors 5'. The gases resulting from the combustion thus pass through the high pressure 6 and low pressure 7 turbines and then escape through an exhaust casing 7' and an exhaust nozzle 200. The energy of the gases is transformed by the turbine rotors 6a and 7a of the high and low pressure turbines 6 and 7 into mechanical energy making it possible to drive the high pressure 9 and low pressure 8 shafts in rotation and consequently, the high pressure 4 and low pressure 3 compressors.

[0063] The fan 2 comprises a mobile disc rotating about the longitudinal axis X and mobile blades 2a regularly distributed on the disc. The fan 2 is preferably of the unducted type. In contrast to a fan 2 of the ducted type, the fan 2 does not comprise a fan casing surrounding the blades 2a. According to this example, the fan 2 may further comprise fixed blades arranged downstream of the mobile blades 2a. These fixed blades are advantageously of variable pitch angle and connected to a blade pitch control system comprising a hydraulic actuator such as a hydraulic cylinder.

[0064] According to another example not illustrated, the blower 2 is of the ducted type.

[0065] The fan disc 2 is rotated by a fan shaft 10. Advantageously, the fan shaft 10 is connected to the low pressure shaft 8, for example via a speed reducer 11. The speed reducer 11 is of the mechanical type. It is for example an epicyclic or planetary gear. 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.

[0066] 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.

[0067] 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.

[0068] The turbomachine 1 further comprises at least one annular casing making it possible to guide the primary and / or secondary air flows F1, F2 in the turbomachine 1 and possibly to take up forces exerted on the turbomachine 1. The turbomachine 1 comprises in particular an annular intercompressor casing 12 arranged axially between the low-pressure compressor 3 and the high-pressure compressor 4. The intercompressor 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.

[0069] The turbomachine 1 may further comprise an annular 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.

[0070] The turbomachine 1 may further comprise an annular inter-turbine casing 14. The inter-turbine casing 14 is arranged axially between the high-pressure turbine 6 and the low-pressure turbine 7.

[0071] The turbomachine 1 further comprises an annular compressor casing 4' centered on the longitudinal axis X. The compressor casing 4' is arranged around the rotor of the high-pressure compressor 4 and connected to the combustion chamber 5. The turbomachine 1 further comprises a turbine casing 6' surrounding the high-pressure and low-pressure turbines 6, 7 and connected to the exhaust casing 7'.

[0072] 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 are arranged radially between the fan shaft 10 and the inlet casing 13. Each first and second bearing 15a, 15b comprises, for example, a rolling bearing arranged between an outer ring and an inner ring. The outer ring is carried by a first bearing support 16a extending radially inward from the inlet casing 13. The inner ring is carried by the fan shaft 10. The rolling bearing is, for example, a row of balls. Advantageously, the rolling bearing comprises two rows of balls.

[0073] The low-pressure shaft 8 is guided in rotation by at least a third and fourth bearing 15c, 15d. The third bearing 15c is arranged radially between the inlet casing 13 and the low-pressure shaft 8. The third bearing 15c comprises a bearing, for example a row of balls, arranged radially between an inner ring and an outer ring. The outer ring is carried by a second bearing support 16b connected to the inlet casing 13. The inner ring is carried by the low-pressure shaft 8. The fourth bearing 15d is arranged radially between the inter-compressor casing 12 and the low-pressure shaft 8. The fourth bearing 15d comprises a bearing, for example a row of balls, arranged radially between an inner ring and an outer ring. The outer ring is carried by a third bearing support 16c connected to the inter-compressor casing 12. The inner ring is carried by the low-pressure shaft 8.

[0074] The high-pressure shaft 9 is guided in rotation by a fifth downstream bearing 15e and a fifth upstream bearing 15g. The fifth downstream bearing 5e is for example arranged radially between the high-pressure shaft 9 and the inter-turbine casing 14. The fifth downstream bearing 15e comprises a bearing, for example a row of balls and a row of rollers arranged radially between an outer ring and an inner ring. The inner ring is carried by the high-pressure shaft 9 and the outer ring is carried by a fourth bearing support 16d connected to the inter-turbine casing 14. The fifth upstream bearing 15g is located for example between the high-pressure shaft 9 and the inter-compressor casing 12. 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.

[0075] The bearings 15a, 15b, 15c, 15d, 15e, 15f, 15g and the speed reducer 11 must be lubricated with oil to ensure their proper operation. To avoid contaminating the related components of the turbomachine 1 with oil, the bearings 15a, 15b, 15c, 15d, 15e, 15f, 15g and the speed reducer 11 are arranged in lubrication enclosures.

[0076] For this purpose, the turbomachine 1 further comprises at least one lubrication enclosure, 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 and the fifth upstream bearing 15g are arranged and a downstream lubrication enclosure 19 in which the fifth and sixth bearings 15e, 15f are arranged.

[0077] The upstream and downstream lubrication chambers 17, 18, 19 are annular. Each upstream and downstream lubrication chamber 17, 18, 19 is delimited externally by a fixed part such as a casing and internally by a rotating part such as a shaft.

[0078] 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 18 is located in the internal shell of the inter-turbine casing 14 and is delimited internally by the high pressure shaft 9.

[0079] The number of lubrication chambers may vary depending on the configuration of the turbomachine 1. In the remainder of the description, the upstream and downstream lubrication chambers 17, 18, 19 will be referred to interchangeably.

[0080] "lubrication enclosure". With reference to Figure 2, the turbomachine 1 further comprises at least one thrust recovery rod 100 making it possible to take up the axial forces generated by the fan 2. The thrust recovery rod 100 is connected upstream to the intermediate casing 12 and downstream to the exhaust casing T via a pylon 102. The thrust recovery rod 100 is for example connected to the internal shell of the intermediate casing 12. The thrust recovery rod 100 is thus located around the compressor casing 4', the combustion chamber 5 and the turbine casing 6'. The pylon 102 makes it possible to connect the turbomachine 1 to the aircraft.

[0081] The turbomachine 1 comprises an accessory drive box 20 making it possible to mechanically drive equipment, also called accessories, of the turbomachine 1, from a mechanical power draw on one of the shafts 8, 9 of the turbomachine 1.

[0082] The drive box 20 is for example manufactured by additive manufacturing, by machining in the mass or by lost wax casting.

[0083] The accessory drive box 20 is advantageously located downstream of the blower 2 and outside one of the casings. Preferably, the accessory drive box 20 is located outside the compressor casing 4', that is to say around this casing. According to another example, the accessory drive box 20 can be located outside the internal shell of the intermediate casing 12. In the remainder of the description, the term "casing" will indifferently designate the compressor casing 4' or the intermediate casing 12, in particular the internal shell of this intermediate casing 12.

[0084] According to the invention, the accessory drive box 20 is suspended from the casing 4', 12. By suspended, it is understood that the accessory drive box 20 is connected to the casing 4', 12 and is located at the lowest point of the turbomachine 1. The accessory drive box 20 is therefore located under a horizontal plane P parallel to the longitudinal axis X and passing through the longitudinal axis X. The accessory drive box 20 (called for simplification "drive box") is for example illustrated in FIG. 3. It extends angularly around the longitudinal axis X between a first circumferential end 21 a and a second circumferential end 21 b. Preferably, the first circumferential end 21 a is located at an angular position around the longitudinal axis X between 9 o'clock and 7 o'clock and the second circumferential end 21 b is located at an angular position around the longitudinal axis X between 3 o'clock and 5 o'clock.

[0085] The drive box 20 comprises a housing 22. The housing 22 extends from the first circumferential end 21a to the second circumferential end 21b. The housing 22 has an upstream face 23a and a downstream face 23b connected by an internal face 23c and an external face 23d.

[0086] The drive box 20 further comprises at least one yoke for suspension to the casing 4', 12. A first yoke 24a is for example connected to the first circumferential end 21a and a second yoke 24b is for example connected to the second circumferential end 21b of the drive box 20. Each yoke 24a, 24b preferably comprises two lugs 24c each having a bore 24d.

[0087] For fixing the drive box 20 to the casing 4', 12, the turbomachine 1 further comprises suspension arms 25 extending radially from the drive box 20 to the casing 4', 12. The suspension arms 25 are for example received in the bores 24d and / or connected to the internal face 23b of the housing 22 of the drive box 20. The suspension arms 25 are for example connecting rods. They thus make it possible to flexibly connect, by providing flexible elements at the bores 24d, the drive box 20 to the casing 4', 12 in order to allow movements of the drive box 20. The turbomachine 1 may also comprise suspension arms extending axially to improve the attachment of the drive box 20 to the casing 4', 12. The drive box 20 further comprises an internal cavity (not visible) delimited by the housing 22 and a gear train arranged in the internal cavity.

[0088] The internal cavity is located in the housing 22 and extends substantially from the first circumferential end 21 a to the second circumferential end 21 b.

[0089] Not shown, the gear train comprises a series of gear wheels meshing together and each mounted coaxially around a respective shaft. The gear wheels of the gear train are driven by taking mechanical power from the low pressure or high pressure shaft 8, 9 for example. The taken mechanical power is transferred to the gear train via a drive shaft coupled to one of the shafts of the gear train.

[0090] The gear train is also coupled to rotors of accessories such as a main fuel pump (MFP) and / or an electric generator (PMA) and / or an air starter (ATS). The gear train also enables the driving of a lubrication unit 26 of the turbomachine 1.

[0091] Indeed, with reference to FIG. 4, the lubrication enclosures 17, 18, 19 are supplied with oil by at least one oil circuit C from an oil reservoir 27. The oil circuit C of the turbomachine 1 is a closed circuit which comprises an oil supply circuit C1 and possibly an oil recovery circuit C2 which are connected to the lubrication enclosures 17, 18, 19. The turbomachine 1 may further comprise a hydraulic control circuit connected to the control system for changing the pitch angle of the fixed blades of the fan 2.

[0092] The lubrication group 26 ensures the circulation of oil in the supply and recovery circuits C1, C2, and possibly in the hydraulic control circuit. The lubrication group 26 comprises an equipment box 28, at least one supply pump 29 and possibly a recovery pump 30.

[0093] With reference to Figure 3, the equipment housing 28 is attached and fixed to the housing 22 of the drive box 20. The equipment housing 28 is for example fixed to the housing 22 by welding, by bolting or by flanges 26a. Advantageously, the equipment housing 28 is fixed to the downstream face 23b of the drive box 20 at the second circumferential end 24b of the drive box 20. The lubrication group 26 is thus preferably located at an angular position around the longitudinal axis X located between 3 o'clock and 5 o'clock, in other words under the horizontal plane P.

[0094] The equipment housing 28 has an internal housing in which the feed pump 29 is arranged. The feed pump 29 comprises a rotor arranged in the internal housing of the equipment housing 28 and coupled to the gear train of the drive box 20 by means of a drive shaft 28a extending in the equipment housing 28 and around which the rotor of the feed pump 29 is mounted. The feed pump 29 allows oil to be sucked from the reservoir 27 and the circulation of the sucked oil in the feed circuit C1.

[0095] Depending on the needs of the supply circuit C, the lubrication group 26 may comprise a plurality of supply pumps 29, each rotor of which is located in the equipment housing 28.

[0096] The lubrication group 26 further comprises an oil inlet 31 connected to the feed pump 29 and connected to the reservoir 27. The oil inlet 31 is provided on the equipment housing 28.

[0097] Referring to Figure 6, the reservoir 27 extends angularly around the longitudinal axis X between a first end 32a and an opposite end 32b. The reservoir 27 extends angularly around the longitudinal axis X between an angular position between 12 o'clock and 2 o'clock and an angular position around the longitudinal axis X between 3 o'clock and 4 o'clock. It is therefore understood that the first 32a is located at an angular position between 12 o'clock and 2 o'clock and the opposite end 32b is located at an angular position between 3 o'clock and 4 o'clock.

[0098] According to the invention, the reservoir 27 is located above the lubrication group 26. It is therefore located at an angular position closer to 12 o'clock than the angular position of the lubrication group 26. Thus, the reservoir is placed above the horizontal plane P, in other words in the high position of the turbomachine 1. The oil can therefore flow by gravity into the lubrication group 26.

[0099] The reservoir 27 comprises an enclosure 33 extending between the ends 32a, 32b of the reservoir 27 and an oil outlet 34 provided in the enclosure 33 and preferably located at the opposite end 32b. The oil outlet 34 is connected to the oil inlet 31 of the lubrication unit 26 for supplying the supply circuit C1 via the supply pump 29. The oil outlet 34 advantageously opens directly into the oil inlet 31 of the lubrication unit 26.

[0100] Advantageously and not illustrated, the enclosure 33 advantageously delimits a first oil compartment Og (zero gravitational force) and / or negative g (negative gravitational force) and a second oil compartment, for example dedicated to the lubrication of the lubrication enclosures 17, 18, 19 in normal operating conditions of the turbomachine 1, i.e. in positive g conditions. The first compartment is preferably located in an internal (or low) position while the second compartment is located in an external (or high) position. According to the invention, and as visible in FIGS. 7, 8 and 9, the reservoir 27 is located at an angular position closer to 12 o'clock than the angular position of the lubrication group 26 and is therefore placed above the lubrication group 26. Thanks to such a configuration, the oil can flow into the lubrication group 26 by gravity.This then makes it possible to prevent the formation of air bubbles in the reservoir 27 and the suction of these air bubbles by the feed pump 28, optimizing the pressure level in the oil circuit C and the hydraulic control circuit. Indeed, the presence of air bubbles in the hydraulic control circuit can harm the operation of the hydraulic actuator and prevent the correct timing of the fixed vanes.

[0101] Furthermore, according to the invention, the reservoir 27 is directly fixed to the equipment housing 28 of the lubrication group 26. Preferably, the reservoir 27 is fixed to the equipment housing 28 by bolting. For example, the opposite end 32b of the reservoir 27 has a fixing collar resting on a base of the equipment housing 28. Bolts connect the fixing collar to the base. Alternatively, the reservoir 27 can be fixed to the equipment housing 28 by any fixing means.

[0102] Thanks to the configuration of the invention in which the reservoir 27 is directly mounted and fixed on the equipment housing 28 of the lubrication group 26, it is possible to dispense with pipes making it possible to connect the oil outlet 34 of the reservoir 27 to the oil inlet 31 of the lubrication group 26. The size of the assembly formed by the reservoir 27 and the lubrication group 26 is therefore reduced and can be easily installed in the engine compartment, in particular around the compressor casing 4' although its diameter is particularly small compared to the diameter of a fan casing. This therefore allows the installation of this assembly in any type of turbomachine, in particular in turbomachines with unducted fans, which do not have these large-diameter fan casings.

[0103] According to a first embodiment of the invention illustrated in Figure 7, the turbomachine 1 further comprises connecting arms 35 connecting the drive box 20 to the tank 27. The connecting arms 35 extend radially. They each comprise an end connected to the housing 22 of the drive box 20, in particular to at least one of the internal faces 23c and / or downstream faces 23b and an opposite end connected to the enclosure 33 of the tank 27 by welding or by additive manufacturing for example. The connecting arms 35 are for example connecting rods. According to a second embodiment of the invention illustrated in Figure 8, the turbomachine 1 further comprises a support 36 located radially between the casing 4', 12 and the tank 27. The support 36 is fixed to the tank 27 and to the drive box 20.

[0104] The support 36 extends angularly around the casing 4', 12 between a first end 36a and an opposite end 36b. Preferably, the support 36 covers an angular sector equal to the angular sector over which the reservoir 27 extends. Thus, the support 36 supports the reservoir 27 over its entire circumferential height.

[0105] The support 36 is advantageously connected to the drive box 20 by bolting. Preferably, the opposite end 36b is fixed to the housing 22 of the drive box 20, in particular to the downstream face 21b of the housing 22 and at the second circumferential end 21b of the drive box 20. Alternatively, the support 36 may be connected to the drive box 20 by any fixing means.

[0106] The first end 36a is fixed to the tank 27 for example by welding, bolting, or any other suitable fixing means. Fixing points may be provided over the entire height of the enclosure 33 of the tank 27 to improve the fixing of the support 36 to the tank 27.

[0107] Furthermore, according to this embodiment, the support 36 is connected to the casing 4', 12. For this purpose, according to this embodiment, the turbomachine 1 comprises at least one connecting arm 35' connecting the support 36 to the casing 4', 12. The connecting arm 35' extends radially from the support 36 to the casing 4', 12. Advantageously, several radial connecting arms 35' can connect the support 36 to the casing 4', 12.

[0108] Such an embodiment makes it possible to fix the tank 27 even if the rigidity of the tank 27 is insufficient for it to be directly connected to the drive box 20. Thanks to such a solution for fixing the tank 27, the mass of the latter can be considerably reduced.

[0109] According to a third embodiment illustrated in Figure 9, the turbomachine 1 comprises at least one connecting arm 35” connecting the tank 27 to the casing 4', 12. The connecting arm 35” extends radially between the tank 27 and the casing 4', 12. By directly connecting the tank 27 to the casing 4', 12, it is possible to reduce the forces exerted on the drive box 20 and to lighten the mass of the turbomachine 1 by doing away with the support 36.

Claims

CLAIMS 1. Turbomachine (1) for an aircraft, the turbomachine (1) having a longitudinal axis (X) and comprising: - an annular casing (4', 12) centered on the longitudinal axis (X), - an accessory drive box (20) which is located outside the housing (4', 12) and which is suspended from the housing (4', 12), the accessory drive box (20) being connected to the housing (4', 12) and comprising: a housing (22) defining an internal cavity, and a gear train arranged in the internal cavity, - a lubrication group (26) comprising: an equipment housing (28) attached and fixed to the housing (22) of the accessory drive box (20), at least one pump (29) located in the equipment housing (28) and comprising a rotor coupled to the gear train, and an oil inlet (31) connected to the pump (29), and - an oil reservoir (27) comprising an oil outlet (34) connected to the oil inlet (31) of the lubrication group (26), characterized in that the reservoir (27) is directly fixed to the equipment housing (28) and is placed above the lubrication group (26) so that the oil flows by gravity into the lubrication group (26).

2. Turbomachine according to the preceding claim, characterized in that the reservoir (27) extends angularly around the longitudinal axis (X) between a first end (32a) located at an angular position between 12 o'clock and 2 o'clock and an opposite end (32b) located at an angular position between 3 o'clock and 4 o'clock.

3. Turbomachine according to one of claims 1 or 2, characterized in that the housing (22) of the accessory drive box (20) extends angularly around the longitudinal axis (X) between a first end circumferential (21a) located at an angular position between 9 o'clock and 7 o'clock and a second circumferential end (21b) located at an angular position between 3 o'clock and 5 o'clock.

4. Turbomachine according to the preceding claim, characterized in that the housing (22) comprises an upstream face (23a) and a downstream face (23b) extending between the first and second circumferential ends (21a, 21b), the equipment housing (28) being attached and fixed to the downstream face (23b), at the level of the second circumferential end (21b).

5. Turbomachine according to any one of the preceding claims, characterized in that it comprises radial suspension arms (25) connecting the accessory drive box (20) to the casing (4', 12).

6. Turbomachine according to any one of the preceding claims, characterized in that it comprises connecting arms (35) connecting the accessory drive box (20) to the tank (27).

7. Turbomachine according to any one of claims 1 to 5, characterized in that it comprises: - a support (36) arranged radially between the casing (4', 12) and the reservoir (27) and extending over an angular sector around the casing (4', 12), and - at least one connecting arm (35') connecting the support (36) to the casing (4', 12), the support (36) being fixed to the tank (27) and to the accessory drive box (20).

8. Turbomachine according to the preceding claim, characterized in that the support (36) is fixed to the accessory drive box (20) by bolting.

9. Turbomachine according to one of claims 7 or 8, in combination with claim 4, characterized in that the support (36) has a first end (36a) fixed to the reservoir (27) and an opposite end (36b) fixed at the second circumferential end (21 b) of the drive box (20).

10. Turbomachine according to any one of claims 1 to 5, characterized in that it comprises at least one connecting arm (35”) connecting the tank (27) to the casing (4', 12).

11. Turbomachine according to any one of the preceding claims, characterized in that the tank (27) is fixed to the equipment housing (28) by bolting.

12. Turbomachine according to any one of the preceding claims, characterized in that the equipment housing (28) is fixed to the housing (22) of the accessory drive box (20) by welding, bolting or by flanges.

13. Turbomachine according to any one of the preceding claims, characterized in that it comprises from upstream to downstream: - a blower (2), - a low pressure compressor (3), - a high pressure compressor (4), - a high pressure turbine (6) mechanically connected to the high pressure compressor (4), and - a low pressure turbine (7) mechanically connected to the low pressure compressor (3), the casing (4', 12) being located around the high pressure compressor (4) or arranged axially between the low pressure and high pressure compressors (3, 4).

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