FR3145192A1 - ASSEMBLY INCLUDING AN ACCESSORY DRIVE BOX AND A LUBRICATION GROUP - Google Patents

Abstract

The invention relates to an assembly (E) for an aircraft turbomachine (1), the assembly (E) comprising: - an accessory training box (21) comprising: first and second walls (25, 26) defining between them an internal cavity (27), and a gear train (28) arranged in the internal cavity (27), intended to be driven by a shaft (9, 8) of the turbomachine (1), and - a lubrication group comprising an oil supply pump (22) and an oil recovery pump (23), the supply and recovery pumps (22, 23) each comprising at least one rotor (22c, 23c) driven by the gear train (28), the assembly (E) being characterized in that the rotors (22c, 23c) of the supply and recovery pumps (22, 23) are arranged on either side of the gear train (28), and in that the rotor (22c) of the feed pump (22) is arranged in the internal cavity (27). Abstract figure: 4

Description

SET COMPRISING AN ACCESSORY DRIVE BOX AND A LUBRICATION GROUP Technical field of the invention

The invention relates to an assembly for an aircraft turbomachine, the assembly comprising an accessory drive box and a lubrication group.

Technical background

An aircraft turbomachine generally extends along and about a longitudinal axis. It includes a gas generator which typically 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.

The rotor of the low-pressure compressor is typically connected to the rotor of the low-pressure turbine by a low-pressure shaft. The rotor of the high-pressure compressor is connected to the rotor of the high-pressure turbine by a high-pressure shaft. The shafts are guided in rotation by means of guide bearings which must be lubricated to ensure their proper operation.

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

In order to ensure the lubrication of 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 an oil recovery circuit for the lubrication chambers.

The oil circuit typically comprises a lubrication unit connected to an oil reservoir. The lubrication unit comprises feed and recovery pumps. The feed pump draws oil from the reservoir and distributes it to the lubrication chambers through the feed circuit, while the recovery pump draws oil from the lubrication chambers and returns it to the reservoir through the recovery circuit. The lubrication unit typically comprises a housing in which oil inlets and outlets for each pump are provided, as well as a drive shaft for the rotors of these pumps. The drive shaft is typically guided in rotation in the housing of the lubrication unit.

In order to drive the rotors of the pumps of the lubrication group, it is known to report and fix the lubrication group on an accessory drive box, better known by the English acronym AGB for "Accessory Gearbox". The accessory drive box makes it possible to transmit mechanical power originating from the turbomachine to the accessories of the turbomachine such as the pumps of the lubrication group. The accessory box typically comprises a housing comprising a first wall and a second wall defining between them an internal cavity in which is arranged a gear train having a series of pinions meshing with each other. The housing of the lubrication group is fixed on one of the walls of the accessory box and one end of the rotor drive shaft is coupled in rotation to one of the pinions of the gear train.

Such a configuration of the assembly formed by the drive box and the lubrication group is not entirely satisfactory. Indeed, such an assembly has a significant mass. Furthermore, its integration into the turbomachine can be difficult given the volume of such an assembly which is incompatible with heavily congested areas of the turbomachine.

Document FR-A1-2 928 696 proposes an assembly comprising an accessory drive box comprising a housing having first and second walls between which is arranged a gear train having a series of pinions meshing with each other. The assembly further comprises an oil supply pump and a first drive shaft for a rotor of the supply pump, and a hydraulic pump and a second drive shaft for the rotor of the hydraulic pump. The oil supply pump is fixed on the first wall and the first drive shaft is rotatably coupled with a pinion of the gear train. The hydraulic pump is fixed on the second wall and the second drive shaft is rotatably coupled with the pinion of the gear train to which the first drive shaft is coupled.

Although reducing the volume of the assembly, this solution is not entirely satisfactory. In fact, each pump remains bulky and thus increases the volume of the assembly on either side of the accessory box. Also, the mass of the assembly is not reduced. In addition, the presence of two pumps attached and fixed to each of the walls increases the number of interfaces with the accessory box, which complicates the assembly of the assembly.

Document WO-A1-2021116570 proposes an assembly comprising a plate and an accessory drive housing comprising a housing having first and second walls. The plate is connected to one of the walls of the housing. The plate has means for fixing various equipment, also called accessories, which can be driven by the gear train of the accessory drive housing. This equipment includes in particular a fuel pump, and the plate also integrates fluid inlet and outlet pipes.

Although reducing the volume of the assembly, this solution remains perfectible. Indeed, the plate remains relatively bulky and massive considering the functions it integrates. Also, the presence of the plate does not allow to significantly reduce the number of interfaces with the accessory box. The assembly of the assembly therefore remains relatively complex.

In this context, there is a need to provide an assembly comprising an accessory drive box and a lubrication unit comprising an oil supply pump and an oil recovery pump, which is compact, lightweight and simple to assemble.

For this purpose, the invention proposes an assembly for an aircraft turbomachine, the assembly comprising:

- an accessory drive box including:

first and second walls defining between them an internal cavity, and

a gear train arranged in the internal cavity, intended to be driven by a shaft of the turbomachine, and

- a lubrication group comprising an oil supply pump and an oil recovery pump, the supply and recovery pumps each comprising at least one rotor driven by the gear train.

The assembly is remarkable in that the rotors of the feed and recovery pumps are arranged on either side of the gear train, and in that the rotor of the feed pump is arranged in the internal cavity.

According to the invention, the rotor of the feed pump is located in the internal cavity of the drive box. In other words, the rotor of the feed pump is located in the drive box. This makes it possible to avoid a bulky casing of the lubrication unit integrating the rotor of the feed pump. The size of the lubrication unit and therefore of the assembly is considerably reduced.

Furthermore, according to the invention, the rotors of the feed and recovery pumps are arranged on either side of the gear train. Such a feature makes it possible to balance the loading of the accessory drive box.

Thanks to the invention, the volume and weight of the assembly is significantly reduced without increasing the number of interfaces between the lubrication group and the drive box.

The assembly of the whole is therefore simplified.

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

- the feed pump includes an oil inlet and an oil outlet provided on the first wall,

- the first wall comprises a cylindrical body extending in projection and having a cylindrical housing opening into the internal cavity and fluidly connected to the oil inlet and outlet, the rotor of the feed pump being arranged in the cylindrical housing,

- the first wall further comprises a bowl for receiving an oil filter, the receiving bowl extending into the internal cavity and being connected to the cylindrical body by an oil outlet pipe,

- the recovery pump comprises a casing comprising at least one oil inlet and an internal housing in which the rotor of the recovery pump is arranged, the casing being attached and fixed to the second wall,

- the housing comprises at least one oil outlet pipe fluidically connected to an oil outlet orifice of the recovery pump, the orifice being provided on the first wall,

- the drive box further includes an oil circulation passage in the internal cavity connecting the pipe to the orifice,

- the feed pump comprises two rotors driven by the gear train and/or in that the recovery pump comprises at least two rotors driven by the gear train,

- the rotor or rotors of the feed pump are driven by a first drive shaft which is coupled to the gear train, and the rotor or rotors of the recovery pump are driven by a second drive shaft which is coupled to the gear train, the first and second shafts extending respectively on either side of the gear train,

- the gear train comprises a series of gear wheels meshing together, and the first and second drive shafts are rotatably coupled to a single gear wheel of the gear train,

- the first wall and/or the second wall comprises at least one valve.

The invention also relates to a turbomachine for an aircraft, comprising:

- a blower configured to drive an air flow separating into a primary air flow and a secondary air flow,

- a primary vein for the flow of primary air,

- a secondary vein for the flow of secondary air,

- an inter-vein compartment separating the primary vein and the secondary vein.

The turbomachine is remarkable in that it further comprises an assembly according to any one of the preceding characteristics and located in the inter-vein compartment.

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:

there is a longitudinal sectional view of an example of an aircraft turbomachine according to the invention;

there is a schematic view of an oil circuit comprising a lubrication circuit and an oil recovery circuit,

there is a perspective view of an assembly according to the invention comprising an accessory drive box and a lubrication group,

there is a side view of the on which the first wall is visible,

there is an enlarged view of the and on which the first cover of the first wall has been removed,

there is a side view of the on which the second wall is visible,

there is another side view of the on which the second wall is visible,

there is an enlarged view of the and on which the second cover of the second wall has been removed,

there is a perspective view of a recovery pump,

there is an exploded perspective view of the recovery pump,

there is a schematic view of the assembly according to the invention.

Detailed description of the invention

An example of an aircraft turbomachine 1 according to the invention is shown very briefly in the . The turbomachine 1 is for example a turboprop.

The turbomachine 1 extends along a longitudinal axis A. An air flow F flows into the turbomachine 1.

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 A.

Furthermore, the terms “longitudinal”, “longitudinally”, are understood in relation to the longitudinal axis A of the turbomachine 1. The terms “radial”, “radially” are understood in relation to a radial axis perpendicular to the longitudinal axis A. The terms “external”, “internal” are understood relatively in relation to the distance from the longitudinal axis A along the radial axis perpendicular to the longitudinal axis A.

The turbomachine 1 comprises, from upstream to downstream, a fan 2, 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.

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 low-pressure shaft 8. They form a low-pressure body.

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.

The low pressure shaft 8 and high pressure shaft 9 are centered on the longitudinal axis A and rotatable about the longitudinal axis A. The high pressure shaft 9 is arranged coaxially around the low pressure shaft 8.

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 into 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 and consequently the low-pressure compressor 3 in rotation.

The fan 2 comprises a mobile disk rotating about the longitudinal axis A and blades 2a regularly distributed on the disk. The fan 2 is for example of the non-ducted 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 another example not illustrated, the fan 2 is of the ducted type.

The disk 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 A. It further comprises satellites meshing with the sun gear and the crown. It further comprises a planet carrier.

The solar is rotationally fixed to the low pressure shaft 8 and forms the input to 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.

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

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 A. The inner and outer shells are, for example, connected by arms.

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 A. The inner and outer shells are, for example, connected by arms.

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.

The turbomachine 1 may further comprise an inter-vein compartment v3 located between the primary vein v1 and the secondary vein v2.

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 inwards 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.

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.

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. The fifth bearing 15e comprises a rolling 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 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.

The bearings 15a, 15b, 15c, 15d, 15e, 15f and the speed reducer 11 must be lubricated with oil to ensure their proper operation. In order not to contaminate the related components of the turbomachine 1 with oil, the bearings 15a, 15b, 15c, 15d, 15e and the speed reducer 11 are arranged in lubrication enclosures.

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 is arranged and a downstream lubrication enclosure 19 in which the fifth and sixth bearings 15e, 15f are arranged.

The upstream and downstream lubrication enclosures 17, 18, 19 are annular. Each upstream and downstream lubrication enclosure 17, 18, 19 is delimited externally by a fixed part such as a casing and internally by a rotating part such as a shaft.

For example, the first upstream lubrication enclosure 17 is located in the internal shell of the inlet casing 13 and is internally delimited 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 internally delimited 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 internally delimited by the high pressure shaft 9.

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 as “lubrication chambers”.

In reference to the , the lubrication enclosures 17, 18, 19 are supplied with oil by at least one oil circuit C. The oil circuit C of the turbomachine 1 is a closed circuit. The oil circuit C comprises an oil supply circuit C1 and an oil recovery circuit C2 which are connected to an oil reservoir 20 and to the lubrication enclosures 17, 18, 19.

In order to allow the circulation of oil in the supply and recovery circuits C1, C2, the turbomachine 1 further comprises an assembly E comprising an accessory drive box 21 and a lubrication group comprising a supply pump 22 and a recovery pump 23 mounted on the accessory drive box 21 and connected respectively to the supply and recovery circuits C1, C2.

The accessory drive box 21 (called for simplification “drive box”) is for example housed in the inter-vein compartment v3. With reference to the , the drive box 21 comprises a housing 24. The housing 24 extends substantially in an elongation direction Y between a first end 24a and an opposite second end 24b. The housing 24 comprises first and second walls 25, 26 and an internal cavity 27 delimited by the first and second walls 25, 26.

The first and second walls 25, 26 extend substantially in the direction of elongation Y. They are preferably curved. The first and second walls 25, 26 are for example made of one piece or assembled together by fixing means of the screw and nut type. They each have an internal face facing the internal cavity 27 and an opposite external face.

In reference to the , the first wall 25 comprises a first structural part 25a and a first cover 25b.

With reference to FIGS. 4 and 5, the first structural part 25a is located for example on the side of the second end 24b of the housing 24. It has a first window 25c passing through the external and internal faces of the first wall 25 and opening into the internal cavity 27. The first structural part 25a further comprises a cylindrical body 251a and a connection block 252a which extend projecting from the external face of the first wall 25. The connection block 252a is carried by the cylindrical body 251a and has opposite lateral faces extending from the cylindrical body 251a and connected by a central face. The faces are planar. The connection block 252a further comprises a transverse face 252a' opposite the external face of the first wall 25. The transverse face 252a' connects the lateral and central faces together. The cylindrical body 251a is hollow and includes a cylindrical housing 251b. The cylindrical housing 251b opens into the internal cavity 27.

The first structural part 25a further comprises an oil filter associated with the feed pump 22 and arranged in a cylindrical receiving bowl 250a. The receiving bowl 250a extends inside the internal cavity 27 and opens onto the first structural part 25a.

The first structural part 25a further comprises an oil outlet pipe 253a connecting an outlet of the cylindrical body 251a to the receiving bowl 250a intended to contain the oil filter. In this way, the pipe 253a connects an outlet of the feed pump 22 to an inlet of the oil filter. The pipe 253a is for example bent.

The first cover 25b is located on the side of the first end 24a of the housing 24. It covers the first window 25c. The first window 25c is therefore closed by the first cover 25b. The first cover 25b is removable. It is attached and fixed to the first structural part 25c by removable fixing means such as a set of screws and nuts 25d. The first cover 25b has fixing brackets 250b for the accessories or equipment.

Referring to Figures 6, 7 and 8, the second wall 26 comprises a second structural part 26a and a second cover 26b.

The second structural part 26a is located on the side of the first end 24a of the housing 24. It has a second window 26c passing through the external and internal faces of the second wall 26 and opening into the internal cavity 27. The second structural part 26a further comprises fixing supports 260a for the accessories or equipment.

The second cover 26b is located on the side of the second end 24b of the housing 24. It covers the second window 26c. The second window 26c is therefore closed by the second cover 26b. The second cover 26b is removable. It is attached and fixed to the second structural part 26a by removable fixing means such as a set of screws and nuts 26d.

The first and second covers 25b facilitate the assembly and maintenance of the assembly E.

The first and second structural parts 25a, 26a form, for example, a monolithic part.

The 24 case is for example manufactured by additive manufacturing or by lost wax casting.

The first and/or second walls 25, 26 may further comprise at least one seat of a valve. The first and/or second walls 25, 26 comprise in particular a by-pass type valve 41a and/or a PRV (for “pressure relief valve” in English) flap valve 41b, sensors or any other equipment necessary for the operation of the feed pump 22.

The internal cavity 27 extends in the direction of elongation Y. It is delimited by the first and second walls 25, 26.

In reference to the , the drive box 21 further comprises a gear train 28 arranged in the internal cavity 27. The gear train 28 comprises a series of toothed wheels 29 each mounted coaxially around a respective shaft 30. The toothed wheels 29 mesh together. The drive of the toothed wheels 29 of the gear train 28 is achieved 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 28 via a drive shaft 40 coupled to one of the shafts 30.

The gear train 28 is further coupled to accessory rotors or equipment. The accessories, also called equipment, comprise for example a main fuel pump 34 (MFP for “Main Fuel Pump” in English) and/or an electric generator 35 (PMA for “Permanent Magnet Alternator” in English) and/or an electric pump 36 (EDP for “Engine Driven Pump) and/or an accessory square drive (HCP for “Hand Crank Pad”) and/or an integrated generator 38 (IDG for “Integrated Drive Generator”) and/or an air starter (ATS for “Air Turbine Starter”).

The drive box 21 further comprises at least one suspension yoke to a fixed structure of the turbomachine 1. A first yoke 40a is for example connected to one of the first and/or second ends 24a, 24b of the housing 24. Preferably, the drive box 21 comprises a first yoke 40a connected to the first end 24a of the housing 24 and a second yoke 40b connected to the second end 24b of the housing 24. Each yoke 40a, 40b preferably comprises two lugs each having a bore for the passage of an axle. The yokes 40a, 40b allow the drive box 21 to be fixed in the turbomachine 1, for example to a casing of the inter-vein compartment v3.

The feed pump 22 allows oil to be sucked from the tank 20 and the oil sucked up to be circulated in the feed circuit C1.

With reference to FIGS. 3, 4 and 5, the feed pump 22 comprises an oil inlet 22a connected to the reservoir 20 and an oil outlet 22b connected to the lubrication chambers 17, 18, 19. According to a particularly advantageous embodiment of the invention, the oil inlets and outlets 22a, 22b are arranged on the first wall 25, in particular on the first structural part 25a of the first wall 25. As can be seen more clearly in FIG. , the oil inlet 22a is for example arranged in the connection block 252a and the oil outlet 22b is arranged in a support 254a shaped to be connected to an outlet pipe forming part of the supply circuit C1. The oil filter being located downstream of the supply pump 22 according to the flow of the oil in the supply circuit C1, the pipe 253a connects an oil outlet of the cylindrical body 251a to an inlet of the oil filter associated with the supply pump 22.

The oil inlets and outlets 22a, 22b of the feed pump 22 are therefore directly formed on the first wall 25 of the drive box 21. Such a feature makes it possible to dispense with a housing dedicated to the feed pump 22 and thus to reduce its size. The size and mass of the assembly E is therefore greatly reduced. Also, the number of interfaces between the drive box 21 and the lubrication group is also reduced, consequently improving the reliability of the assembly E.

The feed pump 22 further comprises at least one rotor 22c. Advantageously, the feed pump 22 comprises two rotors 22c. The presence of two rotors 22c makes it possible to reduce the diameter of the feed pump 22 and to improve the reliability of the feed pump 22 while providing a more stable output compared to a feed pump which would have a single rotor with a similar flow rate.

According to the invention, the rotor(s) 22c of the feed pump 22 are arranged in the internal cavity 27 of the drive box 21. In particular, the rotors 22c are located in the cylindrical housing 251b.

Such a feature makes it possible to dispense with a housing dedicated to the feed pump 22 and thus to reduce its size. The size and mass of the assembly E is therefore greatly reduced. Such a feature of the invention makes it possible to reduce the volume of the assembly E.

The feed pump 22 further comprises a first drive shaft 22d of the rotors 22c. The rotors 22c are mounted coaxially around the first drive shaft 22d. It is thus understood that the first drive shaft 22d is also located in the internal cavity 27. The first drive shaft 22d is coupled to the gear train 28. The first drive shaft 22d is coupled to a toothed wheel 29 of the gear train 28 for its rotational drive.

The recovery pump 23 allows the oil to be sucked from the lubrication chambers 17, 18, 19 and the circulation of the sucked oil in the recovery circuit C2.

With reference to figures 9 and 10, advantageously, the recovery pump 23 comprises a casing 230 attached and fixed to the second wall 26 of the drive box 21. Preferably, the casing 230 is fixed to the second cover 26b of the second wall 26.

The housing 230 has a generally tubular shape extending between first and second ends 230a, 230b. The first end 230a is open and the second end 230b is closed. The housing 230 comprises a cylindrical body 231 and a connection block 232 extending between the first and second ends 230a, 230b. The connection block 232 is carried by the cylindrical body 231 and has opposite lateral faces 232a, 232b extending from the cylindrical body 231 and connected by a central face 232c. The faces 232a, 232b, 232c are planar. The casing 230 further comprises a flange 233 for attachment to the second wall 26 located on the first end 230a of the cylindrical body 231 and a tubular internal housing 234 extending into the cylindrical body 231.

The recovery pump 23 further comprises at least one oil inlet 23a connected to the lubrication enclosures 17, 18, 19. Advantageously, the recovery pump 23 comprises a plurality of oil inlets 23a, for example between two and ten oil inlets 23a, each oil inlet 23a being respectively connected to a lubrication enclosure 17, 18, 19. The oil inlets 23a are provided in the casing 230, advantageously in the connection block 232, and in particular on the central face 232c of the connection block 232.

The recovery pump 23 further comprises at least one housing 23b for receiving a strainer 23b'. Advantageously, the recovery pump 23 comprises as many housings 23b as there are oil inlets 23a. The housings 23b are provided in the connection block 232, in particular on the second lateral face 232b of the connection block 232 and/or on a face of the connection block 232 opposite the end flange 233. Each housing 23b has a circular cross-section and communicates respectively with an oil inlet 23a. The strainers 23b' are arranged respectively in a corresponding housing 23b.

The recovery pump 23 further comprises an oil outlet pipe 235 fluidly connected to an oil outlet port 236 connected to the reservoir 20.

The pipe 235 is secured to the casing 230. It is connected to the cylindrical body 231. The pipe 235 is bent. It comprises a first portion 235a connected to the cylindrical body 231 opposite the second end 232b and a second portion 235b forming a right angle with the first portion 231. The second portion 235b is fluidically connected to the orifice 236. According to a first exemplary embodiment, the pipe 235 extends into the internal cavity 27 and thus passes through the second wall 26. According to this first example, the pipe 235 opens into the orifice 236. According to another example, the drive box 21 further comprises an oil circulation passage in the internal cavity 27 which connects the pipe 235 to the orifice 236.

The orifice 236 is provided on the first wall 25. It is for example formed in the first cover 25b of the first wall 25.

The recovery pump 23 further comprises at least one rotor 23c. Advantageously, the recovery pump 23 comprises a plurality of rotors 23c. Preferably, the recovery pump 23 comprises as many rotors 23c as there are oil inlets 23a. The rotors 23c are arranged in the internal housing 234 of the casing 230.

According to the invention, the rotors 22c, 23c of the feed and recovery pumps 22, 23 are arranged on either side of the gear train 28. Such a characteristic of the invention makes it possible to balance the loading of the gear train.

The recovery pump 23 further comprises a second drive shaft 23d for the rotors 23c. The rotors 23c are mounted around the second drive shaft 23d which extends into the internal housing 234 of the housing 230. The second drive shaft 23d comprises an end portion 23d' which extends outside the internal housing 234. The second drive shaft 23d is coupled to the gear train 28. For example, the end portion 23d' has splines for coupling to a shaft 30 of a toothed wheel 29 of the gear train 28. Preferably, the second drive shaft 23d is coupled to the same toothed wheel 29 to which the first drive shaft 22d of the feed pump 22 is coupled.

Preferably, the first and second drive shafts 22d, 23d extend respectively on either side of the gear train 28.

Claims (12)

Assembly (E) for an aircraft turbomachine (1), the assembly (E) comprising:
- an accessory drive box (21) comprising:
first and second walls (25, 26) defining between them an internal cavity (27), and
a gear train (28) arranged in the internal cavity (27), intended to be driven by a shaft (9, 8) of the turbomachine (1), and
- a lubrication group comprising an oil supply pump (22) and an oil recovery pump (23), the supply and recovery pumps (22, 23) each comprising at least one rotor (22c, 23c) driven by the gear train (28),
the assembly (E) being characterized in that the rotors (22c, 23c) of the feed and recovery pumps (22, 23) are arranged on either side of the gear train (28), and in that the rotor (22c) of the feed pump (22) is arranged in the internal cavity (27). Assembly according to the preceding claim, characterized in that the feed pump (22) comprises an oil inlet (22a) and an oil outlet (22b) provided on the first wall (25). Assembly according to the preceding claim, characterized in that the first wall (25) comprises a cylindrical body (251a) extending in projection and having a cylindrical housing (251b) opening into the internal cavity (27) and fluidly connected to the oil inlet and outlet (22a, 22b), the rotor (22c) of the feed pump (22) being arranged in the cylindrical housing (251b). Assembly according to any one of the preceding claims, characterized in that the first wall (25) further comprises a receiving bowl (250a) for an oil filter, the receiving bowl (250a) extending into the internal cavity (27) and being connected to the cylindrical body (251a) by an oil outlet pipe (253a). Assembly according to any one of the preceding claims, characterized in that the recovery pump (23) comprises a casing (230) comprising at least one oil inlet (23a) and an internal housing (234) in which the rotor (23c) of the recovery pump (23) is arranged, the casing (230) being attached and fixed to the second wall (26). Assembly according to the preceding claim, characterized in that the casing (230) comprises at least one oil outlet pipe (235) fluidically connected to an oil outlet orifice (236) of the recovery pump (23), the orifice (236) being provided on the first wall (25). Assembly according to the preceding claim, characterized in that the drive box (21) further comprises an oil circulation passage in the internal cavity (27) connecting the pipe (235) to the orifice (236). Assembly according to any one of the preceding claims, characterized in that the feed pump (22) comprises two rotors (22c) driven by the gear train (28) and/or in that the recovery pump (23) comprises at least two rotors (23c) driven by the gear train (28). An assembly according to any preceding claim, characterized in that the rotor or rotors (22c) of the feed pump (22) are driven by a first drive shaft (22d) which is coupled to the gear train (28), and the rotor or rotors (23c) of the recovery pump (23) are driven by a second drive shaft (23d) which is coupled to the gear train (28), the first and second shafts (22d, 23d) extending respectively on either side of the gear train (28). Assembly according to the preceding claim, characterized in that the gear train (28) comprises a series of toothed wheels (29) meshing together, and the first and second drive shafts (22d, 23d) are coupled in rotation to the same toothed wheel (29) of the gear train (28). Assembly according to any one of the preceding claims, characterized in that the first wall (25) and/or the second wall (26) comprises at least one valve. Turbomachine (1) for an aircraft, comprising:
- a blower (2) configured to drive an air flow (F) separating into a primary air flow (F1) and a secondary air flow (F2),
- a primary vein (v1) for the flow of the primary air flow (F1),
- a secondary vein (v2) for the flow of secondary air (F2),
- an inter-vein compartment (v3) separating the primary vein (v1) and the secondary vein (v2), characterized in that it further comprises an assembly (E) according to any one of the preceding claims located in the inter-vein compartment (v3).