TURBOMACHINE COMPRISING A SPEED REDUCER INTEGRATING AN ELECTRIC MACHINE.

Abstract

The invention relates to an aircraft turbomachine, comprising: - a speed reducer (4) having an input pinion (40) connected to a power shaft (2) and an output pinion (41) connected to a propeller shaft, and - an electric machine (60) integrated into the speed reducer and configured to supply electrical power to the propeller shaft or to extract mechanical power from the propeller shaft, the electric machine comprising a rotor (61) driven in rotation about an axis coaxial with a longitudinal axis X of the turbomachine and a stator (62) connected to a housing. According to the invention, the input pinion comprises an input shaft (43) offset with respect to an axis of the output pinion, and the speed reducer comprises two substantially parallel intermediate transmission lines capable of transmitting torque from the input pinion to the output pinion, which is intended to drive the rotor in rotation. Figure 3

Description

Title of the invention: TURBOMACHINE COMPRISING A SPEED REDUCER INCORPORATING AN ELECTRIC MACHINE. Field of invention

[0001] The present invention relates to the general field of aeronautics. It relates in particular to a mechanical speed reducer in which an electrical machine is integrated. Technical background

[0002] The role of a mechanical reducer is to modify the speed and torque ratio between the input axis and the output axis of a mechanical system.

[0003] Aircraft equipped with turboprop engines are generally equipped with a mechanical reducer (known by the English acronym "PGB" for Propeller Gear Box) allowing the rotation speeds between the turbine and the propeller to be adapted while allowing an offset to be generated between the axis of rotation of the propeller and the axis of rotation of the turbine. This offset, also called "Offset", allows good integration of the air intake vertically under this reducer.

[0004] In order to improve the performance and efficiency of these turboprops during certain flight phases (take-off, taxiing, etc.), several solutions are possible. One of these solutions consists of hybridizing the turboprop by adding an electric machine (in engine mode) to the reducer in order to provide additional power during the relevant flight phases. It is also possible to use this electric machine (in generator mode) to recover energy or power during certain flight phases.

[0005] There are several gearbox architectures. In the state of the art of turboprop engines, the gearboxes are of the planetary type with offset or epicyclic with offset. There are also so-called compound architectures. - On an offset planetary reducer, the planet carrier is fixed and the crown constitutes the output shaft of the device which rotates in the opposite direction to the solar. - On an offset epicyclic reducer, the crown is fixed and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the solar. - In a compound reducer, no element is fixed in rotation and the power is divided over two parallel intermediate lines. The output wheel rotates in the same direction as the input pinion.

[0006] An epicyclic offset type reducer comprises an input pinion which meshes with a wheel of stage No. 1 which itself drives a central pinion called a sun gear meshing with pinions called satellites which are themselves meshed with a crown. The satellites are held by a frame called a planet carrier. The sun gear, the crown gear and the planet carrier are planetary gears because their axes of revolution coincide with the longitudinal axis X of the propeller. The satellites each have a different axis of revolution equally distributed on the same operating diameter around the axis of the planetary gears. These axes are parallel to the longitudinal axis X.

[0007] A compound type reducer comprises an input pinion, from which two intermediate pinions (called idlers) draw power. The idler pinions then drive, via a second set of teeth, the output line. By varying the number of teeth on the different pinions, it is possible to obtain a speed reduction ratio between the input line and the output line.

[0008] The reducers can be composed of one or more meshing stages. This meshing is ensured in different ways such as by contact, by friction or even by magnetic fields.

[0009] There are several types of contact meshing such as with straight, helical or herringbone teeth.

[0010] Patent document FR-B1-3073569 describes a speed reducer IA allowing to drive the shaft 2A of a propeller 3A of a turboprop in rotation as illustrated in [Fig.l]. The speed reducer IA is equipped with an electric machine 4A intended to supply electrical power to the aircraft. The electric machine 4A is arranged in the volume dedicated to the speed reducer IA so as not to impact the space requirement in this area of ​​the turboprop. The electric machine 4A comprises a hollow rotor 5A which is removably connected to the shaft 2A of the propeller and coaxial therewith. In particular, the shaft 2A of the propeller passes through the rotor 5A. The electric machine comprises a stator 6A which is connected to a stator housing 7A of the turboprop. The stator housing 7A surrounds the shaft 2A and comprises a bore in which the stator 6A is mounted. The latter extends outside the rotor. The configuration of the electric machine is compact.However, this type of integration is viable as long as the level of electrical power required by the aircraft equipment remains moderate. Indeed, the more powerful the electric machine, the greater its volume, which can significantly limit its integration within the speed reducer. However, many pieces of equipment are increasingly powered by electrical energy to reduce the environmental impact.

[0011] There is a need to resolve all or part of the aforementioned drawbacks. Summary of the invention

[0012] The objective of the present invention is to provide a simple and economical solution for integrating an electrical machine into a speed reducer without impacting the size and configuration of the nearby components.

[0013] We achieve this objective in accordance with the invention by means of a turbomachine, in particular for aircraft, having a longitudinal axis X and comprising:

[0014] - a power tree,

[0015] - a propeller shaft centered on the longitudinal axis and intended to drive at least one turbomachine propeller,

[0016] - at least one speed reducer intended to be driven by the power shaft and to rotating the propeller shaft at a speed different from that of the drive shaft, the speed reducer comprising an input gear connected to the power shaft and an output gear connected to the propeller shaft, and

[0017] - at least one electrical machine which is integrated into the speed reducer and which is configured to supply electrical power to the propeller shaft or to draw mechanical power from the propeller shaft, the electrical machine comprising a rotor which is configured to be rotated about an axis coaxial with the longitudinal axis X and a stator connected to a casing of the turbomachine,

[0018] the input pinion comprising an input axis offset relative to an axis of the output pinion and in that the speed reducer comprises at least two intermediate transmission lines which are substantially parallel and which are configured to transmit the torque from the input pinion to the output pinion which is intended to drive the rotor in rotation.

[0019] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, the fact of offsetting the axis of the input pinion from the axis of the output pinion and of providing means of transmitting torque between the input and output pinion makes it possible to arrange the speed reducer in the axis of the propeller. The latter can thus have different types of powers without impacting the space requirement in the volume where the speed reducer is located and also the space requirement within the speed reducer. More precisely, the radial space requirement is reduced and the axial space requirement is small. This arrangement also makes it possible to retain the arrangement of a possible pitch change system for variable pitch propellers. Driving the rotor by the output pinion and vice versa facilitates the integration of the rotor in the speed reducer and improves the performance of the electric machine.

[0020] The turbomachine also comprises one or more of the following features, taken alone or in combination:

[0021] - each intermediate transmission line comprises a first inter gear intermediate mounted rotatably around an axis of rotation and comprising a first toothing intended to mesh with an external toothing of the input pinion.

[0022] - each intermediate transmission line comprises a second inter gear intermediate mounted rotatably around an axis of rotation and comprising a second toothing intended to mesh with an external toothing of the output pinion.

[0023] - the speed reducer comprises a drive wheel driven on the one hand, by the output pinion and driving on the other hand, a complementary pinion mounted on the rotor, the complementary pinion of the rotor comprising an axis parallel to the axis of the propeller shaft.

[0024] - the drive wheel comprises a first external toothing meshing with a internal teeth of the output pinion and a second external tooth meshing with an external tooth of the complementary pinion.

[0025] - the rotor is hollow and is crossed at least in part by the propeller shaft.

[0026] - the stator extends radially outside the rotor.

[0027] - the turbomachine comprises a pitch change system arranged in such a way coaxial with the propeller shaft axis.

[0028] - the pitch change system is arranged at least partly inside the rotor.

[0029] - the turbomachine comprises an air inlet which is arranged below the reducer speed in a vertical direction perpendicular to the longitudinal axis.

[0030] - the electric machine is annular.

[0031] - the electric machine has a generally cylindrical shape.

[0032] - the axis of rotation of the first intermediate gear is collinear with the long axis gitudinal.

[0033] - the axis of rotation the axis of rotation of the second intermediate gear is collinear with the longitudinal axis.

[0034] The invention further relates to an aircraft equipped with such a turbomachine. Brief description of the figures

[0035] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly on reading the detailed explanatory description which follows, of embodiments of the invention given as purely illustrative and non-limiting examples, with reference to the appended schematic drawings in which:

[0036] [Fig. 1] represents an example of a turboprop comprising a reduction mechanism and an electric machine according to the prior art;

[0037] [Fig.2] illustrates an example of arrangement of a reduction mechanism in a turbomachine according to the invention;

[0038] [Fig. 3] is an axial sectional view of an example of a reduction mechanism in which an electric machine according to the invention is integrated;

[0039] [Fig.4] is a perspective view of an example of a reduction mechanism according to the invention;

[0040] [Fig.5] is a top view of the reduction mechanism according to [Fig.4];

[0041] [Fig.6] is a rear view of the reduction mechanism according to [Fig.4];

[0042] [Fig.7] is a front view of the reduction mechanism according to [Fig.4]. Detailed description of the invention

[0043] [Fig.l] shows an axial sectional view of a turbomachine equipped with a reduction mechanism and which has already been described previously.

[0044] [Fig. 2] represents a turbomachine 1 with longitudinal axis X. The turbomachine 1 illustrated is a turboprop equipped with a single unducted propeller intended to be mounted on an aircraft. The turboprop may comprise a pair of counter-rotating, unducted propellers. These turboprops are known by the English expression “open rotor”. Of course, the turbomachine may be a single-flow or double-flow turbojet.

[0045] The turbomachine comprises a power shaft 2, a propeller shaft 3 and a reduction mechanism. The reduction mechanism is advantageously a speed reducer 4 which is intended to be driven by the power shaft 2 and to drive the propeller shaft 3 in rotation at a speed different from that of the power shaft.

[0046] Advantageously, the speed of the power shaft 2 is greater than that of the propeller shaft 3. For example, the speed of the power shaft 2 is of the order of 25,000 revolutions per minute while the speed of the propeller shaft 3 is of the order of 2,000 revolutions per minute. This allows optimal drive of the propeller shaft 3 and efficient propulsion of the aircraft.

[0047] The propeller shaft 3 has an axis of rotation A which is centered on the longitudinal axis X. Advantageously, the propeller shaft 3 extends between a first end 3a and a second end 3b.

[0048] The turbomachine advantageously comprises an unducted propeller 5 which is connected to the propeller shaft 3. The propeller shaft 3 is intended to drive the propeller 5 in rotation so as to provide propulsion for the aircraft. The propeller 5 comprises a cylindrical casing 6 which is fixed to the first end 3a of the propeller shaft 3.

[0049] Each propeller 5 comprises blades 7 which are arranged regularly around the longitudinal axis X. The blades 7 comprise feet which are each housed respectively in a housing provided in a ring (not shown) and extend from this ring. The ring is centered on the longitudinal axis and is integral in rotation with the cylindrical casing 6.

[0050] A pitch change system 10 is provided for changing the timing or the orientation of the blades 7 of each propeller 5 around a radial pitch axis. This makes it possible to orient the blades in a desired angular position depending on the operating conditions of the turbomachine and the different flight phases. In the present example, the pitch change system 10 is arranged along the longitudinal axis of the turbomachine and more precisely still along the axis of the propeller shaft 3.

[0051] As we can see in [Fig.2], the speed reducer 4 is positioned in the upstream part of the turbomachine. The pitch change system 10 is advantageously located downstream of the speed reducer 4.

[0052] In the present invention, the terms "upstream" and "downstream" are defined in relation to the circulation of gases in the turbomachine and here along the longitudinal axis X and in [Fig.2] from left to right.

[0053] The speed reducer 4 and the pitch change system 10 are arranged in an internal volume of the turbomachine. Advantageously, but not limitingly, the speed reducer 4 is arranged in the internal volume of the nacelle where there is little space available.

[0054] In particular, the turbomachine 1 schematically comprises a stator casing 11. The stator casing 11 is arranged so as to form an enclosure 12 surrounding the speed reducer 4. The stator casing 11 is advantageously independent of the casings of the turbomachine such as the inlet casing of the turbomachine 1. The casing 11 is secured to the nacelle of the turbomachine. A lubricant mist prevails in the enclosure 12. The enclosure 12 is traversed at least in part by the propeller shaft 3 along the longitudinal axis X.

[0055] The casing 11 advantageously, but not limited to, comprises an upstream portion 13 and a downstream portion 14. The upstream portion 13 and the downstream portion 14 are separated from each other here. The upstream portion 13 of the casing 11 comprises a first opening 15 allowing the passage of the propeller shaft 3. The first opening 15 is delimited by a cylindrical wall 16 centered on the longitudinal axis X. The downstream portion 14 comprises a second opening 17 allowing at least part of the pitch change system 10 to pass through. The second opening 17 is delimited by a cylindrical skirt 18 (better visible in [Fig. 3]) which is centered on the longitudinal axis X.

[0056] The upstream part 13 and the downstream part 14 are fixed together, for example using a radial flange and a bolted connection. The downstream part 14 can be made in one piece or be made in two portions 14a, 14b as is the case in FIGS. 2 and 3.

[0057] With reference to [Fig. 3], the propeller shaft 3 is rotated relative to the casing 11 by means of bearings. In the present example, two upstream bearings 19 are mounted upstream of the enclosure 12. Advantageously, the two upstream bearings 19 are mounted upstream of the speed reducer 4. Each upstream bearing 19 comprises an inner ring 20 secured to the propeller shaft 3 and an outer ring 21 secured to the cylindrical wall 16 of the casing. In the example illustrated, the first upstream bearing 19a comprises roller bearings and the second upstream bearing 19b comprises ball bearings.

[0058] The propeller shaft 3 is also advantageously driven downstream by a downstream bearing 23. The downstream bearing 23 is mounted downstream of the enclosure 12. More precisely, the downstream bearing 23 is mounted downstream of an output pinion 41 which will be described in more detail later. The downstream bearing 23 comprises an inner ring 24 which is integral with a cylindrical shaft 45 of the output pinion 4L. The downstream bearing 23 comprises an outer ring 25 which is integral with an annular wall 26 of the stator casing 11.

[0059] The enclosure 12 is advantageously but not exclusively closed upstream by seals at the level of the upstream bearings 19 allowing the propeller shaft 3 to pass through, and downstream by seals at the level of the cylindrical skirt 18.

[0060] In the present embodiment, the pitch change system 10 is arranged at least partly in the enclosure 12 and extends along the longitudinal axis. Advantageously, the pitch change system 10 comprises a shaft or a member which is fixed to the second end 3b of the propeller shaft 3.

[0061] With reference to [Fig. 2], the turbomachine 1 also comprises an air inlet 30 which is arranged below the speed reducer 4 in a vertical direction perpendicular to the longitudinal axis (and on the plane of [Fig. 2]). In other words, the air inlet is directly above the longitudinal axis. Advantageously, the air inlet 30 is extended downstream by an air sleeve 31 which extends below the speed reducer 4 and the pitch change system 10. Here, the air inlet 30 is defined in a radial plane which is arranged upstream of the output pinion 4L. However, the air inlet could be placed downstream of the output pinion 4L.

[0062] Advantageously, the air handle 31 advantageously has an S shape. The air handle 31 has an air outlet 32 ​​which is defined in a radial plane which is located downstream of the pitch change system. The speed reducer 4 and the pitch change system 10 are located in particular in a hollow area of ​​the air handle 31 and delimit the available volume.

[0063] In [Fig.3], the speed reducer 4 comprises a gear train with intermediate transmission lines which is also called a compound reducer or "compound" in English terminology. The speed reducer 4 is known by the English acronym PGB for "Propeller Gear Box" or RGB for "Reduction Gear Box". The compound type speed reducer requires a load balancing system to equalize the loads between intermediate lines.

[0064] The speed reducer 4 comprises an input pinion 40 and an output pinion 41 which are rotatable. The input pinion 40 is connected to the power shaft. Advantageously, the input pinion 40 is carried by a shaft 42 and are coaxial. In the present embodiment, the input pinion 40 has an input axis 43 which is parallel to the longitudinal axis X of the turbomachine. The power shaft 2 is coupled to the shaft 42 of the input pinion 40 for example using splines so that the power shaft 2 is integral with the input pinion 40. The power shaft thus drives the input pinion 40 in rotation.

[0065] The power shaft is advantageously a turbine shaft which is conventionally included in a turbomachine.

[0066] The output pinion 41 is connected to the propeller shaft 3. The connection is made for example using splines so that the propeller shaft 3 is integral with the output pinion 4L. The output pinion 41 has an output axis 44 which coincides with that of the propeller shaft (and with the longitudinal axis). The output pinion is in other words movable in rotation about the output axis 44 collinear with the longitudinal axis X. In other words, the axis of the input pinion 40 is offset, here radially, from the output axis 44 of the output pinion 4L.

[0067] The output pinion 41 comprises in this embodiment a cylindrical shaft 45 extending along the output axis 44. The output pinion 41 comprises a rim 46 which extends radially around the cylindrical shaft 45 and which carries at least one external toothing 47.

[0068] In [Fig. 4], the speed reducer 4 comprises torque transmission means 48 which are configured to transmit the torque from the input pinion 40 to the output pinion 4L. In particular, the power transmitted by the input pinion 40 is distributed by the torque transmission means 48 before being transferred to the output pinion 4L.

[0069] Advantageously, the torque transmission means 48 comprise two first intermediate gears 49 rotatably mounted about axes which are parallel to each other. The axes of the first intermediate gears 49 are also parallel to the longitudinal axis. The two first intermediate gears 49 comprise teeth 50 which mesh with a toothing 51 of the input gear 40.

[0070] In the present example, the transmission means 48 comprise two intermediate transmission lines 55. The two intermediate lines 55 are substantially parallel (more or less inclined by 5°) and are substantially identical. In another example configuration, the intermediate lines 55 may be inclined at an angle greater than 5°.

[0071] With reference to Figures 4 and 5, each intermediate transmission line 55 advantageously comprises a second intermediate pinion 52 rotatably mounted around an axis of rotation. The latter is coaxial with a corresponding intermediate line 55. The axes of the second intermediate gears 52 are also parallel to the longitudinal axis. The second intermediate gears 52 each comprise an external toothing 53 which mesh with the external toothing 47 of the output gear.

[0072] Advantageously, the first intermediate pinions 49 and the second intermediate pinions 52 are integral in rotation. In particular, the first pinions 49 and second pinions 52 of each intermediate line 55 are carried by a shaft 54. This shaft can include flexibility and be used for balancing loads thanks to its flexibility. The shaft 54 ​​can also be used for torque measurement.

[0073] Advantageously, but not limitingly, the shaft 54 ​​extends between a first end 54a and a second end 54b. Each first intermediate gear 49 is arranged at the first end of the shaft 54 ​​and each second intermediate gear 52 is arranged at the second end of the shaft 54.

[0074] Advantageously, the second intermediate gears 52 are arranged upstream of the first intermediate gears 49.

[0075] The teeth 51, 47 of the input and output gears may be straight (parallel to the longitudinal axis), helical or herringbone. Similarly, the teeth of the input and output gears may be separated into several helices for reasons of operation, assembly, manufacturing, control, repair or replacement.

[0076] With reference to Figures 4 and 5, at least one of the input gears, output gear, first intermediate gears and second intermediate gears is separated into two half-portions: • a first portion consisting of a rim which carries the first helix of the teeth. This first helix meshes with that of another pinion of the speed reducer; • a second portion consisting of a rim which carries the second helix of the teeth. This second helix meshes with that of another pinion.

[0077] In the present embodiment, the input pinion 40 comprises two half-portions respectively carrying a first helix 51a and a second helix 51b. The first helix 51a meshes with a first helix 50a of each of the first intermediate pinions 49 and the second helix 51b meshes with a second helix 50b of each of the first intermediate pinions 49. The output pinion 41 comprises two half-portions respectively carrying a first helix 47a and a second helix 47b. The first helix 47a meshes with a first helix 53a of each of the second pinions 52 and the second helix 47b meshes with a second helix 53b of each of the second intermediate pinions 52.

[0078] Advantageously, the direction of the first helix is ​​different from that of the second helix. The directions are opposite.

[0079] Of course, each of the gables can be formed from a single piece.

[0080] As illustrated in the various figures 2 to 6, the speed reducer 4 further comprises at least one electrical machine 60. The latter is more precisely integrated into the speed reducer 4. This configuration makes it possible to limit the space requirement in the turbomachine. The speed reducer 4 comprises space that was not previously used. The electrical machine 60 is configured so as to supply electrical power to the propeller shaft, and to the aircraft (generator mode). The electrical machine can also advantageously take mechanical power from the propeller shaft (motor mode). The aircraft comprises for this purpose an electrical circuit (not shown) which is connected on the one hand, to the electrical machine 60 and on the other hand, to various equipment of the aircraft.

[0081] In the context of this exemplary embodiment, the speed reducer comprises a single electrical machine.

[0082] The turbomachine 1 could comprise two electric machines. In this case, the two electric machines would be mounted in series and more precisely one after the other along the longitudinal axis X. Similarly, a single power electronic block would be used for the two electric machines.

[0083] The electrical machine comprises a rotor 61 and a stator 62. The rotor 61 is configured to be driven in rotation about an axis coaxial with the axis of the propeller shaft and the stator 62 is connected to the stator casing 11 of the turbomachine. According to an advantageous characteristic, the output pinion 41 of the speed reducer 4 is intended to drive the rotor 61 of the electrical machine 60 in rotation.

[0084] Advantageously, the rotor 61 is hollow. It is arranged so as to be traversed at least in part by the propeller shaft 3.

[0085] More precisely still and as illustrated in [Fig. 3], the rotor 61 has a cylindrical body 61a of right circular section. The body 61a extends between a first end 61aa and a second end 61ab (along the longitudinal axis). The rotor 61 comprises an internal bore 61b with an axis coaxial with the axis of the propeller shaft 3. This configuration makes it possible to further contain the space requirement in the speed reducer and around it.

[0086] Advantageously, the pitch change system 10 is arranged at least partly inside the rotor 61. As can be seen in [Fig. 3], the interface between the propeller shaft 3 and the pitch change system 10 is located inside the rotor 61.

[0087] With reference to figures 3 to 6, the speed reducer 4 comprises a drive wheel 63 driven on the one hand by the output pinion 41 and driving on the other hand a complementary pinion 64 mounted on the rotor 61. The complementary pinion 64 includes an axis parallel to the axis of the propeller shaft 3.

[0088] Advantageously, but not limitatively, the complementary pinion 64 is formed in a single piece with the rotor 61. The complementary pinion 64 is in this case mounted radially outside the body of the rotor 61. Alternatively, the complementary pinion 64 is attached to the body of the rotor 61. Advantageously, the complementary pinion 64 is arranged at the first end 61aa of the rotor.

[0089] The drive wheel 63 is mounted radially inside the output pinion 4L. For this purpose, the drive wheel 63 comprises a first external toothing 65 meshing with an internal toothing 66 of the output pinion 4L. Advantageously, but not limitatively, the external diameter D2 of the first external toothing 65 is less than the internal diameter DI of the output pinion 4L. The arrangement of the drive wheel 63 inside the output pinion 41 makes it possible to reduce the radial size and to move closer to the axis of the propeller shaft coaxial with the rotor of the electric machine.

[0090] Advantageously, the drive wheel 63 comprises a second external toothing 67 meshing with an external toothing 68 of the complementary pinion 64. According to this embodiment, the external diameter D3 of the second external toothing 67 is less than the diameter D2 of the first external toothing 65.

[0091] As shown in particular in Figures 3 and 4, the drive wheel 63 extends between a first end 63a and a second end 63b. The first external toothing 65 is advantageously arranged at the first end 63a and the second external toothing 67 is advantageously arranged at the second end 63b.

[0092] Advantageously, the drive wheel 63 remains in the same XY plane. Generally, the pinions do not move along the longitudinal axis.

[0093] The stator 62 of the electrical machine 60 extends radially outside the rotor 61. Advantageously, the stator 62 comprises a cylindrical body 62a coaxial with the axis of the rotor 61. In the present example, the stator 62 is fixed to the casing 11. The stator 62 is hollow and receives the rotor which extends inside it. In particular, the cylindrical body 62a also comprises an internal bore.

[0094] Of course, the stator 62 and the rotor 61 can have different shapes as long as they are complementary and can be easily integrated into the available space of the speed reducer.

[0095] The electric machine 60 can operate indifferently in motor mode and in generator motor mode.

[0096] In the case where the electric machine operates in generator mode (the propeller shaft or the turbomachine 1 sends power to the electric machine), the input pinion 40 meshes with the first intermediate pinions 49 as is visible in [Fig.6]. The rotation of the first intermediate gears 49 causes the rotation of the second intermediate gears 52. The latter mesh with the output gear 41 whose internal toothing 66 is engaged with the first external toothing 65 of the drive wheel 63 as can be seen in [Fig.6] and in [Fig.7]. The rotation of the output gear 41 causes the rotation of the drive wheel 63. The latter rotates the complementary gear 64 mounted on the rotor 61 via the external toothing.

[0097] In the case where the electric machine 60 operates in motor mode (the electric machine sends power to the propeller shaft), the complementary pinion 64 of the rotor is driven in rotation and drives the drive wheel 63 via the second external toothing 67. The first external toothing 65 of the drive wheel 63 (which also carries the first toothing) drives the output pinion 4L. The latter drives the intermediate lines 55 then the input pinion 40.

Claims

Claims

1. A turbomachine (1), in particular for an aircraft, having a longitudinal axis X and comprising: - a power shaft (2), - a propeller shaft (3) centered on the longitudinal axis and intended to drive at least one propeller (5) of the turbomachine, - at least one speed reducer (4) intended to be driven by the power shaft (2) and to rotate the propeller shaft (3) at a speed different from that of the drive shaft, the speed reducer (4) comprising an input pinion (40) connected to the power shaft (2) and an output pinion (41) connected to the propeller shaft (3), and - at least one electrical machine (60) which is integrated in the speed reducer (4) and which is configured to supply electrical power to the propeller shaft (3) or to take mechanical power from the propeller shaft,the electric machine (60) comprising a rotor (61) which is configured to be driven in rotation about an axis coaxial with the longitudinal axis X and a stator (62) connected to a casing (11) of the turbomachine, characterized in that the input pinion (40) comprises an input axis (43) offset relative to an axis of the output pinion (41) and in that the speed reducer (4) comprises at least two intermediate transmission lines (55) which are substantially parallel and which are configured to transmit the torque from the input pinion (40) to the output pinion (41) which is intended to drive the rotor (61) in rotation.,

2. Turbomachine (1) according to the preceding claim, characterized in that each intermediate transmission line (55) comprises a first intermediate pinion (49) rotatably mounted around an axis of rotation and comprising a first toothing intended to mesh with an external toothing of the input pinion (42).

3. Turbomachine (1) according to claim 1 or 2, characterized in that each intermediate transmission line (55) comprises a second intermediate pinion (52) rotatably mounted around an axis of rotation and comprising a second toothing intended to mesh with an external toothing (47) of the output pinion (41).

4. Turbomachine (1) according to any one of the preceding claims, characterized in that the speed reducer (4) comprises a drive wheel (63) driven on the one hand by the output pinion (41) and driving on the other hand a complementary pinion (64) mounted on the rotor (61), the complementary pinion (64) of the rotor (61) comprising an axis parallel to the axis of the propeller shaft (3).

5. Turbomachine (1) according to the preceding claim, characterized in that the drive wheel (63) comprises a first external toothing (65) meshing with an internal toothing of the output pinion (41) and a second external toothing (67) meshing with an external toothing (68) of the complementary pinion (64).

6. Turbomachine (1) according to any one of the preceding claims, characterized in that the rotor (61) is hollow and is traversed at least in part by the propeller shaft (3).

7. Turbomachine (1) according to any one of the preceding claims, characterized in that the stator (62) extends radially outside the rotor (61).

8. Turbomachine (1) according to any one of the preceding claims, characterized in that it comprises a pitch change system (10) arranged coaxially with the axis of the propeller shaft (3).

9. Turbomachine (1) according to the preceding claim, characterized in that the pitch change system (10) is arranged at least partly inside the rotor (61).

10. Turbomachine (1) according to any one of the preceding claims, in which an air inlet (30) is arranged below the speed reducer (4) in a vertical direction perpendicular to the longitudinal axis (X).

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