Assembly for training a propeller-driven aircraft and aircraft comprising such an assembly

Abstract

Assembly (1) for driving a propeller-driven aircraft (100), comprising: a single turbomachine (10) having a drive shaft (12) extending in a longitudinal direction (X), a main transmission shaft (30a) preferably extending parallel to the longitudinal direction (X), a main reduction gear (20) connecting the drive shaft (12) to the main transmission shaft (30a), at least one secondary transmission shaft (30b, 30c) preferably extending parallel to the longitudinal direction (X), an intermediate transmission (50) connecting the main transmission shaft (30a) to the at least one secondary transmission shaft (30b, 30c), a main propeller reduction gear (40a) connected to the main transmission shaft (30a) and having a main output shaft (48a), at least one secondary propeller reduction gear (40b, 40c), each reduction gear secondary propeller (40b, 40c) being connected to the at least one secondary transmission shaft (30b,30c) corresponding and having a secondary output shaft (48b, 48c). Figure for abstract: Figure 1,

Description

Title of the invention: Assembly for training a propeller-driven aircraft and aircraft comprising such an assembly Disclosure area

[0001] The present disclosure relates to an assembly for training a propeller-driven aircraft and to an aircraft each wing of which is provided with such an assembly. State of the art

[0002] This disclosure is based on an improved architecture of the mechanical transmission of an aircraft having a turbomachine per wing mechanically driving several propellers distributed along the wing. A turbomachine is understood to mean a thermal engine intended for driving an aircraft and comprising a gas turbine.

[0003] The present disclosure aims to propose an efficient power transmission kinematic chain which reduces the stresses to which the various elements of the assembly are subjected and therefore the weight of the assembly. The present disclosure also aims to reduce the cost of the assembly.

[0004] Document FR 3 062 692 A1 discloses an assembly comprising:

[0005] a turbomachine having a drive shaft extending in a longitudinal direction, the drive shaft being intended to be driven in rotation at an engine rotation speed,

[0006] a propeller reducer connected to the engine shaft and having an output shaft, the main propeller reducer being configured to rotate the main output shaft at an output rotational speed lower than the engine rotational speed, the output shaft extending parallel to the longitudinal direction and carrying a propeller.

[0007] On the other hand, document FR 1 264 560 A discloses an assembly comprising:

[0008] two turboprop engines on each wing, each turboprop engine having a drive shaft extending in a longitudinal direction, the drive shaft being intended to be driven in rotation at an engine rotation speed,

[0009] four propeller reducers each connected to one of the drive shafts and each having an output shaft, each output shaft extending parallel to the longitudinal direction and carrying a propeller, and

[0010] four drive shafts connected together by an intermediate transmission, the drive shafts being connected to the drive shafts in the event of engine failure.

[0011] Each propeller is rotated by the corresponding turboprop. The transmission of the turboprop, in particular the propeller reducers, is sized to transmit the total power of the engine to the propeller. The reducers propeller shafts are only connected to each other by the intermediate transmission in the event of failure of one of the engines. Disclosure Statement

[0012] To achieve the aforementioned aims, in accordance with the present disclosure, the assembly for training a propeller-driven aircraft comprises:

[0013] a single turbomachine having a drive shaft extending in a longitudinal direction, the drive shaft being intended to be driven in rotation at an engine rotation speed,

[0014] a main transmission shaft preferably extending parallel to the longitudinal direction,

[0015] a main reducer connecting the motor shaft to the main transmission shaft and configured to rotate the main transmission shaft at a main transmission rotation speed lower than the engine rotation speed,

[0016] at least one secondary transmission shaft preferably extending parallel to the longitudinal direction,

[0017] a plurality of propeller reducers comprising a main propeller reducer and at least one secondary propeller reducer, the main propeller reducer being connected to (driven by) the main transmission shaft and having a main output shaft, the main propeller reducer being configured to rotate the main output shaft at a main output rotational speed lower than the main transmission rotational speed, the main output shaft preferably extending parallel to the longitudinal direction and being intended to receive a main propeller,

[0018] an intermediate transmission connecting the main transmission shaft to the at least one secondary transmission shaft and configured to drive the secondary transmission shaft at a secondary transmission rotational speed,

[0019] each secondary propeller reducer is connected to (driven by) the corresponding secondary transmission shaft and has a secondary output shaft, each secondary propeller reducer being configured to rotate the corresponding secondary output shaft at a secondary output rotational speed lower than the secondary transmission rotational speed, each secondary output shaft preferably extending parallel to the longitudinal direction and being intended to receive a secondary propeller.

[0020] Thus, the propeller reducers are always connected to each other and the turbomachine is arranged in parallel with the mechanical connection connecting the propeller reducers to each other. The turbomachine thus drives the plurality of propeller reducers and the applied forces are consequently permanently distributed between the propeller reducers, so that the propeller reducers are not sized to receive all the power of the turbomachine, but at most (depending on the number of propeller reducers) half of the power of the turbomachine. Finally, the main reducer allows the rotation speed to be reduced for the main output shaft and each secondary output shaft.

[0021] According to another characteristic in accordance with the disclosure, preferably the intermediate transmission comprises a main angle transmission, an intermediate transmission shaft, at least one secondary angle transmission, the main angle transmission connecting the main transmission shaft to the intermediate transmission shaft, each secondary angle transmission connecting the intermediate transmission shaft to the corresponding at least one secondary transmission shaft, the intermediate transmission shaft extending in a transverse direction perpendicular to the longitudinal direction, the main angle transmission being configured to rotate the intermediate transmission shaft, each secondary angle transmission being configured to rotate the at least one secondary transmission shaft at a secondary transmission rotation speed.

[0022] According to an additional characteristic, the secondary transmission rotation speed is preferably equal, in absolute value, to the main transmission rotation speed.

[0023] According to another characteristic, the main angle transmission is preferably structurally identical to the at least one secondary angle transmission.

[0024] Thus, it is only necessary to use one angle transmission model.

[0025] According to an additional characteristic, preferably the main angle transmission comprises a main bevel gear and a main bevel wheel, the main bevel gear being rigidly fixed to the main transmission shaft, the main bevel wheel being rigidly fixed to the intermediate transmission shaft, the main bevel wheel cooperating with the main bevel gear, and each secondary angle transmission comprises a secondary bevel gear and a secondary bevel wheel, each secondary bevel gear being rigidly fixed to the at least one corresponding secondary transmission shaft, each secondary bevel wheel being rigidly fixed to the intermediate transmission shaft, each secondary bevel gear cooperating with the corresponding secondary bevel wheel.

[0026] According to another characteristic in accordance with the invention, the intermediate transmission is configured so that at least one of the at least one secondary transmission shaft rotates in the opposite direction relative to the main transmission shaft.

[0027] Thus, the propellers can rotate in opposite directions.

[0028] According to an additional characteristic in accordance with the invention, preferably the main angle transmission and / or the secondary angle transmission comprises a first coupling part and a second coupling part which can be connected to the intermediate transmission shaft, coupling the intermediate transmission shaft to the first part instead of the second part, and vice versa, causing a reversal of the direction of rotation of the at least one secondary output shaft

[0029] Thus, the reversal of the direction of rotation of the at least one secondary propeller is easily achieved.

[0030] According to another characteristic in accordance with the invention, the main reducer preferably comprises a motor toothed wheel rigidly fixed to the motor shaft and a driven toothed wheel rigidly fixed to the main transmission shaft.

[0031] According to another characteristic in accordance with the invention, the main propeller reducer is preferably identical to each secondary propeller reducer.

[0032] Thus, the production cost is reduced by reducing the number of different elements.

[0033] According to another characteristic in accordance with the disclosure, preferably the main transmission shaft has an upstream end by which the transmission shaft is connected to the main propeller reducer and a downstream end by which the main transmission shaft is connected to the intermediate transmission, and the main reducer is linked to the main transmission shaft at the upstream end.

[0034] The invention further relates to an aircraft comprising a fuselage, two wings fixed to the fuselage and a aforementioned assembly carried by each wing, in which the main transmission shaft is arranged between the at least one secondary transmission shaft and the fuselage.

[0035] According to an additional characteristic, preferably the assembly has, in the longitudinal direction, an upstream part comprising the propeller reducers and a downstream part comprising the intermediate transmission, and the turbomachine extends from the main reducer in the longitudinal direction in the direction going from the upstream part towards the downstream part.

[0036] According to another characteristic in accordance with the disclosure, preferably the at least one secondary transmission shaft comprises a single secondary transmission shaft and the at least one secondary propeller reducer comprises a single secondary propeller reducer. Brief description of the figures

[0037] Other features and advantages of the present disclosure will become apparent from the following detailed description, with reference to the accompanying drawings in which:

[0038] [Fig-1] schematically represents from above an aircraft comprising a set for training the aircraft by wing, according to a first embodiment,

[0039] [Fig.2] represents on an enlarged scale the area marked II in [Fig.l],

[0040] [Fig.3] schematically represents from above an assembly for the training of a aircraft according to a second embodiment. Detailed Description of Disclosure

[0041] [Fig.l] represents an aircraft 100 comprising a fuselage 102, a right wing 104, a left wing 106 and two assemblies 100 carried respectively by the right wing 104 and the left wing 106 of the aircraft 100.

[0042] The aircraft 100 extends in a longitudinal direction X corresponding to the direction of elongation of the fuselage 102. The longitudinal direction X is substantially horizontal when the aircraft is on the ground or in cruising flight. The aircraft has a transverse direction Y, perpendicular to the longitudinal direction X and substantially horizontal when the aircraft is on the ground or in cruising flight. The transverse direction Y corresponds substantially to the direction of elongation of the left wing 104 and of the right wing 106. The aircraft 100 further has a direction of elevation Z which is substantially vertical when the aircraft is on the ground or in cruising flight, the direction of elevation Z being perpendicular to the direction of elongation X and to the transverse direction Y.

[0043] The assembly 1 carried by the left wing 106 is symmetrical with respect to the median plane of the aircraft (perpendicular to the transverse direction Y) of the assembly 100 carried by the right wing 104.

[0044] Each assembly 1 essentially comprises a single turbomachine 10, a main reducer 20, a main transmission shaft 30a, a main propeller reducer 40a, a main propeller 90a, an intermediate transmission 50, a secondary transmission shaft 30b, a secondary propeller reducer 40b and a secondary propeller 90b.

[0045] Each assembly 1 has, along the longitudinal direction X, an upstream part 2 and a downstream part 4. The upstream part 2 is located at the leading edge of the left wing 104 or the right wing 106. The downstream part 4 is located at the trailing edge of the right wing 104 or the left wing 106.

[0046] More generally, along the longitudinal direction X, reference is made to upstream and downstream in accordance with the direction of air flow under the action of the main propeller 90a and the secondary propeller 90b, illustrated by the arrow 92.

[0047] Each assembly 1 comprises a single turbomachine 10. Consequently, the aircraft 100 comprises a single turbomachine 10 per wing, i.e. two turbomachines 10 in total. Each turbomachine 10 comprises a gas turbine. In the first illustrated embodiment, the turbomachines 10 comprise turboprops.

[0048] As illustrated in particular in [Fig. 2], the turbomachine 10 comprises an air inlet 14 supplying air to a compressor or a group of compressors 15, downstream of which is a combustion chamber 16. The gases resulting from the combustion expand in a turbine or a group of turbines 18, which rotates a motor shaft 12 at an engine rotation speed around an engine rotation axis 11. extending in the longitudinal direction X. The motor shaft 12 has an upstream end 13 and a downstream end 19 along the engine rotation axis 11. The engine rotation speed is of the order of 20,000 rpm to 30,000 rpm. The motor shaft 12, the compressor group 15, the combustion chamber 16 and the turbine group 18 are centered on the engine rotation axis IL. The air inlet 14 is located under the engine rotation axis 11 along the elevation direction Z.

[0049] The main reducer 20 connects the motor shaft 12 to the main transmission shaft 30a. The main reducer 20 is constituted by a motor gear wheel 22 and a driven gear wheel 24. The motor gear wheel 22 is rigidly fixed to the upstream end 13 of the motor shaft 12. The turbomachine 10 is arranged downstream of the motor gear wheel 22. The driven gear wheel 24 is rigidly fixed to the main transmission shaft 30a. The main transmission shaft 30a is rotated about a main rotation axis 31a at a main transmission rotation speed. The reduction ratio of the main reducer 20 is preferably between 1 / 2 and 1 / 5, corresponding to the ratio between the main transmission rotation speed and the motor rotation speed.

[0050] The main shaft 30a extends in the longitudinal direction X between a main upstream end 32a and a main downstream end 34a. The driven gear 24 is fixed to the main transmission shaft 30a at the main upstream end 32a of the main shaft 30a.

[0051] The main propeller reducer 40a forms a gearbox. In the first illustrated embodiment, the main propeller reducer 40a comprises an epicyclic gear train 4L. The epicyclic gear train 41 comprises a sun gear 42, a fixed ring gear 44, satellites 45 and a planet carrier 46. The satellites are preferably 3 to 6 in number.

[0052] The sun gear 42 is fixed to the driven gear 24. The sun gear 42 is centered on the main rotation axis 31a and meshes with the satellites 45. The satellite carrier 46 comprises a main output shaft 48a coaxial with the main rotation axis 31a and fingers 47 off-center with respect to the main rotation axis 31a, the satellites 45 being mounted to rotate on the fingers 47 of the satellite carrier 46. The satellite carrier 46 is rotatable about the main rotation axis 31a. The fixed ring gear 44 meshes with the satellites 45. The fixed ring gear 44 is internally toothed and centered on the main rotation axis 31a. The fixed ring gear 44 is rigidly fixed to a stator of the turbomachine 10.

[0053] The main propeller 90 is fixed on the main output shaft 48a of the main propeller reducer 40a. The main output shaft 48a of the main propeller reducer 40a is rotated about the main rotation axis 31a by the main propeller reducer 40a at a main output rotation speed lower than the main transmission rotation speed. The reduction ratio of the main propeller reducer 40a is preferably between 1 / 5 and 1 / 10, corresponding to the ratio between the main output rotation speed and the main transmission rotation speed.

[0054] The main output rotation speed is preferably of the order of 1,000 revolutions per minute to 2,500 revolutions per minute.

[0055] The secondary shaft 30b extends in the longitudinal direction X between a secondary upstream end 32b and a secondary downstream end 34b.

[0056] The intermediate transmission 50 connects the main transmission shaft 30a to the secondary transmission shaft 30b. The intermediate transmission 50 comprises a main angle transmission 52a, an intermediate transmission shaft 55 and a secondary angle transmission 52b.

[0057] The intermediate transmission shaft 55 extending in the transverse direction Y between a first end 54 and a second end 56.

[0058] The main bevel gear 52a connects the main downstream end 34a of the main transmission shaft 30a to the first end 54 of the intermediate transmission shaft 55. The main bevel gear 52a comprises a main bevel gear 51a and a main bevel wheel 53a meshing with each other. The main bevel gear 51a is rigidly fixed to the downstream end 34a of the main transmission shaft 30a. The main bevel wheel 53a has a main inner face 57a and a main outer face 58a. The first end 54 of the intermediate transmission shaft 55 is rigidly fixed to the main outer face 58a of the main bevel wheel 53a.

[0059] The secondary bevel gear 52b connects the second end 56 of the intermediate transmission shaft 55 to the downstream end 34b of the secondary transmission shaft 30b. The secondary bevel gear 52b comprises a secondary bevel gear 51b and a secondary bevel gear 53b meshing with each other. The secondary bevel gear 51b is rigidly fixed to the downstream end 34b of the secondary transmission shaft 30b. The secondary bevel gear 53b has a secondary inner face 57b and a secondary outer face 58b. The second end 56 of the intermediate transmission shaft 55 is rigidly fixed to the secondary outer face 58b of the secondary bevel gear 53b.

[0060] The main bevel gear 52a rotates the intermediate transmission shaft 55 at an intermediate rotational speed. In the illustrated embodiment, the intermediate rotational speed is lower than the main transmission rotational speed.

[0061] The main angle gear 52a and the secondary angle gear 52b are structurally identical, but they are arranged back to back, the main internal face 57a of the main bevel gear 53a facing the fuselage 102, likewise the secondary inner face 57b of the secondary bevel gear 53b faces the fuselage 102. Consequently, the secondary bevel gear 52b rotates the secondary transmission shaft 30b around a secondary rotation axis 31b at a secondary transmission rotation speed identical to the main transmission rotation speed of the main transmission shaft 30a, but in the opposite direction.Alternatively, the secondary drive shaft 30b could rotate in the same direction as the main drive shaft 30a by connecting the first end 54 of the intermediate drive shaft 55 to the secondary inner face 57b of the secondary bevel gear 53b or by connecting the second end 56 of the intermediate drive shaft 55 to the secondary inner face 57b of the secondary bevel gear 53b, in other words by making the main inner face 57a of the main bevel gear 53a and the secondary inner face 57b of the secondary bevel gear 53b both face the fuselage 102 or the main outer face 58a of the main bevel gear 53a and the secondary outer face 58b of the secondary bevel gear 53b both face the fuselage 102.Therefore, the direction of rotation of the secondary transmission shaft 30b can be easily reversed by rotating the main bevel gear 52a 180 degrees about the main rotation axis 31a or the secondary bevel gear 52b 180 degrees about the secondary rotation axis 31b.

[0062] In the illustrated embodiment, the secondary propeller reducer 40b is identical to the main propeller reducer 40a. The secondary propeller reducer 40b comprises a secondary output shaft 48b on which the secondary propeller 90b is fixed. The secondary output shaft 48b of the secondary propeller reducer 40b is rotated about the secondary rotation axis 31b by the secondary propeller reducer 40b at a secondary output rotational speed identical to the main output rotational speed, but in the opposite direction.

[0063] The first embodiment makes it possible to have an efficient transmission kinematic chain by separating the power flow generated by the turbomachine on the one hand towards the main propeller 90a and on the other hand towards the secondary propeller 90b, in order to reduce the mass as much as possible by sizing the mechanical elements taking into account the separation into two equal parts of the power flow. The main reducer 20 sees the entire power of the turbomachine 10 transit, then this power is separated into two. All of the propeller reducers are thus sized for the same power, half of the power supplied by the turbomachine. The use of a secondary propeller reducer 40b identical to the main propeller reducer 40a makes it possible to reduce development and manufacturing costs thanks to the increase in the volume of parts produced and maintenance costs thanks to the Common spare parts. These propeller reducers integrate the power transmission functions, but also the oil system and propeller services such as the pitch setting system or overspeed protection.

[0064] A bypass of the lubrication system of the turbomachine 10 makes it possible to lubricate the main reducer 20, attached to the turbomachine 10.

[0065] The main propeller reducer 40a and the secondary propeller reducer 40b each have their own lubrication system and the accessories necessary for the propeller (pitch setting, de-icing, etc.).

[0066] The second embodiment illustrated in [Fig. 3] differs from the first embodiment illustrated in Figures 1 and 2 in three independent aspects.

[0067] According to a first aspect, in the second illustrated embodiment, each assembly 1 essentially comprises a single turbomachine 10, a main reduction gear 20, a main transmission shaft 30a, a main propeller reduction gear 40a, a main propeller 90a, an intermediate transmission 50, a first secondary transmission shaft 30b, a first secondary propeller reduction gear 40b, a first secondary propeller 90b, a second secondary transmission shaft 30c, a second secondary propeller reduction gear 40c and a second secondary propeller 90c.

[0068] The intermediate transmission 50 comprises a main angle gear 52a, a first secondary angle gear 52b, a second secondary angle gear 52 and an intermediate transmission shaft 55 comprising a first portion 55a and a second portion 55b. The main angle gear 52a, the first secondary angle gear 52b and the second secondary angle gear 52c are structurally identical. The first portion 55a of the intermediate transmission shaft 55 connects the main angle gear 52a to the first secondary angle gear 52b and the second portion 55b of the intermediate transmission shaft 55 connects the first secondary angle gear 52b to the second secondary angle gear 52c.

[0069] The main propeller reducer 40a, the first secondary propeller reducer 40b and the second secondary propeller reducer 40c are identical.

[0070] According to a second aspect, in the second illustrated embodiment, the main reducer 20 is connected to the downstream end 19 of the motor shaft 12 and to the downstream end 34a of the main transmission shaft 30a.

[0071] According to a third aspect, the first secondary bevel gear 52b and the second secondary bevel gear 52c are arranged in the same manner, each being arranged back to back with respect to the main bevel gear 52a, so that the first secondary transmission shaft 30b and the second secondary transmission shaft 30c both rotate in the same direction and at the same speed as the main transmission shaft 30a, but in the opposite direction with respect to the main transmission shaft 30a.

[0072] According to a fourth aspect, the assembly further comprises transmission joints 60 arranged between the transmission shaft 55 and the main angle gear 52a, the first secondary angle gear 52b and the second secondary angle gear 52c. The transmission joints 60 form couplings allowing slight angular offsets in order to take up the deformations of the structure of the wings of the aircraft during the flight phases. The transmission joints 60 may be of the bellows type, spring-plate couplings or other similar couplings.

[0073] Of course, the disclosure is in no way limited to the embodiments described for illustrative, non-limiting purposes. Thus, the epicyclic gear train 41 of the main propeller reducer 40a and of the secondary propeller reducer 40 could be replaced by any type of well-known reducer, such as a double epicyclic gear train (the satellites comprising two integral toothed wheels of different diameters), a compound type reducer (several levels of simple gears) or the like. Furthermore, it would be possible to make the axis of rotation of the satellites fixed instead of the crown 44.

Claims

Claims

1. Assembly (1) for training a propeller-driven aircraft (100), comprising: a single turbomachine (10) having a drive shaft (12) extending in a longitudinal direction (X), the drive shaft (12) being intended to be driven in rotation at an engine rotation speed, a main transmission shaft (30a), a main reduction gear (20) connecting the drive shaft (12) to the main transmission shaft (30a) and configured to drive the main transmission shaft (30a) in rotation at a main transmission rotation speed lower than the engine rotation speed, at least one secondary transmission shaft (30b, 30c), a plurality of propeller reduction gears (40a, 40b, 40c) comprising a main propeller reduction gear (40a) and at least one secondary propeller reduction gear (40b, 40c), the main propeller reduction gear (40a) being connected to the main transmission shaft (30a) and having a main output shaft (48a),the main propeller reducer (40a) being configured to rotate the main output shaft (48a) at a main output rotation speed lower than the main transmission rotation speed, the main output shaft (48a) being intended to receive a main propeller (90a), an intermediate transmission (50) connecting the main transmission shaft (30a) to the at least one secondary transmission shaft (30b, 30c) and configured to drive the secondary transmission shaft (30b, 30c) at a secondary transmission rotation speed, the intermediate transmission (50) comprises a main angle gear (52a), an intermediate transmission shaft (55), at least one secondary angle gear (52b, 52c), the main angle gear (52a) connecting the main transmission shaft (30a) to the intermediate transmission shaft (55), each secondary angle gear (52b,52c) connecting the intermediate transmission shaft (55) to the at least one corresponding secondary transmission shaft (30b, 30c), the intermediate transmission shaft (55) extending in a transverse direction (Y) perpendicular to the longitudinal direction (X), the main angle transmission (52a) being configured to rotate the intermediate transmission shaft (55), each secondary angle transmission (52b, 52c) being configured to rotate the at least one, a secondary transmission shaft (30b, 30c) at a secondary transmission rotational speed, each secondary propeller reducer (40b, 40c) is connected to the corresponding secondary transmission shaft (30b, 30c) and has a secondary output shaft (48b, 48c), each secondary propeller reducer (40b, 40c) being configured to rotate the corresponding secondary output shaft (48b, 48c) at a secondary output rotational speed lower than the secondary transmission rotational speed, each secondary output shaft (48b, 48c) being intended to receive a secondary propeller (90b, 90c).

2. Assembly according to the preceding claim in which the main angle transmission (52a) is structurally identical to the at least one secondary angle transmission (52b).

3. An assembly according to any one of the preceding claims, wherein: the main bevel gear (52a) comprises a main bevel gear (51a) and a main bevel wheel (53a), the main bevel gear (51a) being rigidly fixed to the main transmission shaft (30a), the main bevel gear (53a) being rigidly fixed to the intermediate transmission shaft (55), the main bevel gear (53a) cooperating with the main bevel gear (51a), and each secondary bevel gear (52b, 52c) comprises a secondary bevel gear (51b, 51c) and a secondary bevel gear (53b, 53c), each secondary bevel gear (51c) being rigidly fixed to the at least one corresponding secondary transmission shaft (30b, 30c), each secondary bevel gear (53b, 53c) being rigidly fixed to the intermediate transmission shaft (55), each pinion secondary conical (51b, 51c) cooperating with the corresponding secondary conical wheel (53b, 53c).

4. An assembly according to any preceding claim wherein the intermediate transmission (55) is configured so that at least one secondary transmission shaft (30b) rotates in the opposite direction relative to the main transmission shaft (30a).

5. An assembly according to any preceding claim wherein the main reducer (20) comprises a motor gear wheel (22) rigidly fixed to the motor shaft (12) and a driven gear wheel (24) rigidly fixed to the main transmission shaft (30a).

6. An assembly according to any preceding claim in which the main propeller reducer (40a) is identical to each secondary propeller reducer (40b, 40c).

7. An assembly according to any preceding claim wherein: the main drive shaft (30a) has an upstream end (32a) by which the main drive shaft (30a) is connected to the main propeller reducer (40a) and a downstream end (34a) by which the main drive shaft (30a) is connected to the intermediate transmission (50), and the main reducer (20) is connected to the main drive shaft (30a) at the upstream end (32a).

8. An aircraft (100) comprising a fuselage (102), two wings (104, 106) attached to the fuselage (102) and an assembly (1) according to any one of the preceding claims carried by each wing (104, 106), wherein the main drive shaft (30a) is disposed between the at least one secondary drive shaft (30b, 30c) and the fuselage (102).

9. Aircraft according to the preceding claim in which: the assembly has, in the longitudinal direction (X), an upstream part (2) comprising the propeller reducers (40a, 40b, 40c) and a downstream part (4) comprising the intermediate transmission (50), and the turbomachine (10) extends from the main reducer (20) in the longitudinal direction (X) in the direction (92) going from the upstream part (2) towards the downstream part (4).

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