TURBOMACHINE FOR AN AIRCRAFT

Abstract

Turbomachine (10) for an aircraft, said turbomachine (10) comprising a gas generator having at least one compressor (1a, 1b), a combustion chamber (1c) and at least one turbine (1d, 1e), said at least one turbine (1d, 1e) having a shaft (3) connected by a mechanical reduction gear (6) to a propulsion propeller (S), the shaft (3) being coupled to the solar element (11) by a reverse-rotating gearbox (20) with the same rotational speed such that a rotation of the shaft (3) about its axis (X) at a given speed causes a rotation in the opposite direction of the solar element (11) about the same axis (X) at the same speed. Figure for the abbreviation: Figure 3

Description

Title of the invention: TURBOMACHINE FOR AN AIRCRAFT

[0001] The present invention relates to the field of aircraft turbomachinery, in particular equipped with mechanical reducers. Technical background

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

[0003] New generations of turbofan engines, particularly those with a high bypass ratio, include a mechanical gearbox to drive the shaft of a propulsion propeller such as a fan. Typically, the gearbox's purpose is to transform the high rotational speed of the power turbine shaft into a slower rotational speed for the propeller-driving shaft.

[0004] Such a reduction gear comprises a central pinion, called the sun gear, a ring gear, and pinions called planet gears, which mesh between the sun gear and the ring gear. The planet gears are held by a frame called a planet carrier. The sun gear, ring gear, and planet carrier are planetary gears because their axes of revolution coincide with the longitudinal axis of the turbomachine. The planet gears each have a different axis of revolution and are equally spaced on the same operating diameter around the axis of the planet gears. These axes are parallel to the longitudinal axis of the turbomachine.

[0005] Several gearbox architectures exist. In the state of the art of turbofan engines, gearboxes are of the planetary or epicyclic type. In other similar applications, there are so-called differential or "compound" architectures.

[0006] - on a planetary reducer, the planet carrier is fixed and the ring constitutes the output shaft of the device which rotates in the opposite direction to the solar.

[0007] - on an epicyclic reducer, the ring gear is fixed and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the solar panel.

[0008] - on a differential reducer, no element is fixed for rotation. The ring rotates in the opposite direction to the solar panel and the satellite carrier.

[0009] Gear reducers can be composed of one or more meshing stages. This meshing is achieved in various ways, such as by contact, friction, or magnetic field. There are several types of contact meshing, such as with spur or herringbone teeth.

[0010] In order to improve the performance of an aircraft equipped with turbomachinery, it may be preferable to rotate the propulsion propellers in different directions from one turbomachine to another. In such solutions, and in order to optimize costs and the In industrial processes, it is necessary to minimize the number of different parts from one turbomachine to another.

[0011] The reducer is a device ideally positioned in the motor to reverse the direction of rotation of the propeller without impacting the compressor and the turbine.

[0012] The invention addresses this need, with the objective of minimizing the impact on the performance of the reducer in question compared to an optimized configuration without reversal of direction. Summary of the invention

[0013] The invention proposes a turbomachine for an aircraft, this turbomachine comprising a gas generator having at least one compressor, a combustion chamber and at least one turbine, said at least one turbine having a shaft connected by a mechanical reducer to a propulsion propeller, the reducer having a solar element coupled to the shaft, a ring extending around the solar element, and satellites which are meshed respectively with the solar element and the ring and which are carried by a satellite carrier,

[0014] characterized in that the shaft is coupled to the solar element by a gearbox with reversing direction of rotation and the same rotational speed so that a rotation of the shaft around its axis at a given speed causes a rotation in the opposite direction of the solar element around the same axis at the same speed.

[0015] The solution proposes adding, upstream of a reducer, a direction reversing gear case, that is to say, a gear case whose sole purpose is to reverse the direction of rotation. This case is integrated between the input shaft and the sun gear of the reducer.

[0016] The solution proposed below is notably compatible: • of a simple or multi-stage reducer; • of an epicyclic, planetary or differential reducer, • of straight, herringbone, helical, etc. teeth.

[0017] Advantageously, the gear housing comprises:

[0018] - a first shaft section centered on said axis and comprising a first set of teeth frustoconical extending around the axis, this first section being rotationally fixed to said tree,

[0019] - a second shaft section centered on said axis and comprising a second set of teeth frustoconical extending around the axis, this second section being fixed in rotation to the said solar system, and

[0020] - at least one first frustoconical pinion having a first set of teeth meshed with the first teeth of the first section and the second teeth of the second section.

[0021] The turbomachine according to the invention may comprise one or more of the following features, taken individually or in combination with each other: • said first section of tree is formed in one piece with said tree, or is coupled to said tree by grooves; • said second section of tree is formed in one piece with said solar, or is coupled to said solar by grooves; • said sprockets include a second sprocket comprising a second set of teeth meshed with the first set of teeth of the first section and the second set of teeth of the second section;

[0022] — the first and second pinions are diametrically opposed with respect to said axis; • the first pinion, or each of the first and second pinions, has an axis of rotation perpendicular to said axis; • said the first and second teeth of the first and second sections have the same number of teeth; • the first pinion, or each of the first and second pinions, has an axis of rotation inclined with respect to said axis; • the first and second teeth of the first and second sections have a different number of teeth; • the first section is guided by a first guiding platform extending around the first section; • the second section is guided by a second guide bearing extending around the second section; • the pinion or each pinion is guided by at least one third guide bearing extending around the pinion; • the guide bearings are rolling bearings and in particular double row ball bearings; • said at least a third bearing is interposed between the teeth of the pinion guided by this bearing and said shaft; • the bearings include external rings having external tabs or flanges for fixing to a housing; • the housing is attached to a stator of the turbomachine.

[0023] The present invention also relates to an aircraft comprising at least two turbomachines, each turbomachine comprising a gas generator having at least one compressor, a combustion chamber and at least one turbine, said at least one turbine having a shaft connected by a mechanical reduction gear to a propulsion propeller, the reduction gear having a solar element coupled to the shaft, a ring gear extending around the solar system, and the satellites which are meshed respectively with the solar system and the corona and which are carried by a satellite carrier,

[0024] characterized in that one of the turbomachines is as defined above, and the other of the turbomachines has its shaft which is coupled to the solar by a gearbox with reversing direction of rotation and at the same speed of rotation, which is inactive, so that a rotation of the shaft around its axis at a given speed causes a rotation in the same direction of the solar around the same axis at the same speed.

[0025] Advantageously, the inactive housing comprises:

[0026] - a first shaft section centered on said axis and comprising a first set of teeth frustoconical extending around the axis, this first section being rotationally fixed to said tree,

[0027] - a second shaft section centered on said axis and comprising a second set of teeth frustoconical extending around the axis, this second section being fixed in rotation to the said solar system,

[0028] - at least one frustoconical pinion having a first set of teeth meshing with the first teeth of the first section and the second teeth of the second section,

[0029] the first and second sections being rotationally fixed to a housing of the casing which carries said at least one pinion and which is mounted freely in rotation vis-à-vis a stator of the turbomachine. Brief description of the figures

[0030] Other features and advantages will become apparent from the following description of a non-limiting embodiment of the invention with reference to the accompanying drawings in which:

[0031] [Fig-1] [Fig.1] is a schematic view of an aircraft equipped with turbomachinery,

[0032] [Fig.2] [Fig.2] is a schematic axial cross-sectional view of a turbomachine;

[0033] [Fig. 3] [Fig. 3] is a very schematic axial cross-sectional view of a turbomachine according to the invention, showing in particular a reducer and a gear housing;

[0034] [Fig.4] [Fig.4] is a schematic cross-sectional view of a reducer and a gear housing for a turbomachine according to the invention;

[0035] [Fig.5] [Fig.5] is a schematic perspective and partial section view of the reducer and housing of [Fig.4];

[0036] [Fig.6] [Fig.6] is a schematic perspective view of the reducer and housing of [Fig.4];

[0037] [Fig.7] [Fig.7] is a schematic perspective view of an alternative embodiment of the gear housing;

[0038] [Fig.8] [Fig.8] is a very schematic axial cross-sectional view of another turbomachine according to the invention, showing in particular a reducer and a gear case;

[0039] [Fig.9] [Fig.9] is a schematic cross-sectional view of a reducer and a gear housing for a turbomachine according to the invention;

[0040] [Fig. 10] [Fig. 10] is a schematic perspective and partial section view of the reducer and housing of [Fig. 9];

[0041] [Fig. 11] [Fig. 11] is a schematic perspective view of the reducer and housing of [Fig. 9];

[0042] [Fig. 12] [Fig. 12] is a schematic perspective view of an alternative embodiment of the gear housing; and

[0043] [Fig. 13] [Fig. 13] is a schematic axial cross-sectional view of an alternative embodiment of the gear housing. Detailed description of the invention

[0044] Figure 1 shows an aircraft comprising a central fuselage and two lateral wings, each carrying one or two turbomachines 10. As mentioned above, it may be more efficient to rotate the propulsion propellers of the turbomachines 10 in opposite directions. For example, the turbomachines 10 located on one wing may rotate in a first direction of rotation, and the turbomachines 10 located on the other wing may rotate in a second direction opposite to the first. Alternatively, the two turbomachines 10 located on each wing could rotate in opposite directions.

[0045] Figure 2 shows a turbomachine 10 comprising, in a conventional manner, a fan propeller S, a low-pressure compressor 1a, a high-pressure compressor 1b, an annular combustion chamber 1e, a high-pressure turbine Id, a low-pressure turbine 1e, and an exhaust nozzle Ih. The high-pressure compressor 1b and the high-pressure turbine Id are connected by a high-pressure shaft 2 and together form a high-pressure (HP) housing. The low-pressure compressor 1a and the low-pressure turbine 1e are connected by a low-pressure shaft 3 and together form a low-pressure (LP) housing.

[0046] The blower propeller S is driven by a blower shaft 4 which is connected to the BP shaft 3 by means of a mechanical reducer 6. This reducer 6 is generally of the planetary or epicyclic type.

[0047] Although the following description relates to a planetary or epicycloidal type reducer, it also applies to a mechanical differential in which its three essential components are the planet carrier, the ring gear, and the sun gear, are mobile in rotation, the rotational speed of one of these components depending in particular on the difference in speeds of the other two components.

[0048] The reducer 6 is positioned in the upstream part of the turbomachine. A fixed structure schematically comprising, here, an upstream part 5a and a downstream part 5b which make up the motor or stator housing 5 is arranged to form an enclosure E surrounding the reducer 6. This enclosure E is here closed upstream by seals at the level of a bearing allowing the passage of the blower shaft 4, and downstream by seals at the level of the passage of the BP shaft 3.

[0049] Figure 3 shows a turbomachine 10 according to the invention. The preceding description made with reference to Figure 2 applies to the turbomachine 10 of Figure 3.

[0050] In [Fig. 3], the reducer 6 is more clearly visible and schematically represented. The reducer is associated with a gear case 20 which is located here just at the input of the reducer 6.

[0051] The reducer 6 can take the form of different architectures depending on whether certain parts are fixed or rotating. At the input, the reducer 6 is connected to the shaft BP 3 by the housing 20 and includes a solar element 11 coupled to the shaft BP 3 by the housing 20.

[0052] Conventionally, the solar 11, whose axis of rotation coincides with the X axis of the turbomachine 10, drives a series of pinions called satellites 12, which are equidistant circumferentially on the same diameter around the axis of rotation X. This diameter is equal to twice the operating center distance between the solar 11 and the satellites 12. The number of satellites 12 is generally defined between three and seven for this type of application.

[0053] The set of satellites 12 is held by a frame called a satellite carrier 13. Each satellite 12 rotates around its own Y axis, and meshes with a ring 14.

[0054] At the output of the reducer 6, we have: • In an epicyclic configuration, the set of satellites 12 drives the planet carrier 13 in rotation around the X axis of the turbomachine. The ring 14 is fixed to the motor or stator housing 5 via a ring carrier 15 and the planet carrier 13 is fixed to the blower shaft 4; • In a planetary configuration, the set of satellites 12 is held by a satellite carrier 13 which is fixed to the motor or stator housing 5. Each satellite drives the ring which is brought to the blower shaft 4 via a ring carrier 15.

[0055] Each satellite 12 is mounted freely in rotation by means of a bearing around a Y axis. The Y axes of rotation of the satellites 12 are distributed around the X axis and parallel to this X axis.

[0056] The particularity of the turbomachine 10 of [Fig.3] is related to the fact that the BP shaft 3 is coupled to the solar 11 by the gearbox 20 with reversing direction of rotation and at the same rotational speed so that a rotation of the BP 3 shaft around the X axis at a given speed causes a rotation in the opposite direction of the solar 11 around the X axis at the same speed.

[0057] Figures 4 and 5 show a more concrete example of the realization of the reducer 6 and the housing 20.

[0058] In the example shown, the gear housing 20 comprises:

[0059] - a first shaft segment 22 centered on the X axis and comprising a first frustoconical teeth 22a extending around the X axis, this first section 22 being rotationally fixed to the shaft BP 3,

[0060] - a second shaft section 24 centered on the X axis and comprising a second set of teeth frustoconical 24a extending around the X axis, this second section 24 being rotationally fixed to the solar 11, and

[0061] - a first pinion 26 comprising at least one first meshing tooth 26a with the first toothing 22a of the first section 22 and the second toothing 24a of the second section 24.

[0062] The first shaft section 22 can be formed in one piece with the shaft BP 3, or be coupled to this shaft by splines 30 as in the example shown.

[0063] The second shaft section 24 can be formed in one piece with the solar 11, or be coupled to the solar 11 by grooves 32 as in the example shown.

[0064] As can be seen in the drawings, the axes of rotation of the sections 22, 24 are aligned with the X axis. As for the pinion 26, it has an axis of rotation Z in the example shown which is perpendicular to the X axis.

[0065] The first and second teeth 22a, 24a of the first and second sections 22, 24 here have the same number of teeth. These teeth can be straight, inclined, etc.

[0066] The direction of rotation is reversed between the input and output of the housing 20. However, it is understood that the output rotational speed is equal to the input speed. This allows the same parameters to be maintained at the input of the main gearbox and therefore avoids the need for redesigning it. It should be noted that if the gearbox is equipped with helical or herringbone gears, since the direction of rotation is reversed at the input of the main gearbox, it may be desirable to "reverse" the pinion in order to maintain the direction of the axial forces on the teeth.

[0067] The housing 20 can include or carry bearings 34, 36 for guiding the first and second sections 22, 24, as well as a bearing 38 for guiding the pinion 26.

[0068] Advantageously, the guide bearings 34, 36, 38 are rolling bearings and in particular double row ball bearings as illustrated in the drawings.

[0069] Alternatively, bearings 34, 36, 38 could be smooth, for example.

[0070] The drawings show that the bearings 34, 36, 38 include external rings comprising tabs 34a, 36a, 38a or external flanges for fixing to a housing 42.

[0071] The housing 20 preferably includes a casing 42 which is fixed to the stator 5 of the turbomachine 10, as schematically illustrated in [Fig.3].

[0072] Fig. 7 illustrates an alternative embodiment of the gear housing 20 which here includes a second pinion 28 comprising a second tooth 28a meshed with the first tooth 22a of the first section and the second tooth 24a of the second section 24. Alternatively, more than two pinions could be used.

[0073] In the example shown, the gears 26, 28 are identical and are diametrically opposed with respect to the X axis. The Z axis of rotation of the second gear 28 is aligned with that of the first gear, the gears 26, 28 rotating in opposite directions.

[0074] In the context of the aircraft 1 according to the invention mentioned above in relation to [Fig.1], this aircraft comprises at least two turbomachines 10.

[0075] Each turbomachine 10 is of the type illustrated in [Fig.2].

[0076] Among these turbomachines 10, one is as defined above with reference to Figures 3 to 6. The other turbomachine 10' is preferably of the type illustrated in [Fig.8].

[0077] This turbomachine 10' has its shaft BP 3 which is coupled to the solar 11 of the reducer 6 by a gearbox 20' with reversing direction of rotation and at the same speed of rotation, which is inactive or passivated, so that a rotation of the shaft BP 3 around its axis X at a given speed causes a rotation in the same direction of the solar 11 around the same axis X at the same speed.

[0078] The goal here is that the turbomachines 10, 10' have their propellers S which operate in opposite directions of rotation while having similar masses.

[0079] The inactive housing 20' of the turbomachine 10' may include:

[0080] - a first shaft segment 22 centered on the X axis and comprising a first frustoconical teeth 22a extending around the X axis, this first section 22 being rotationally fixed to the shaft BP 3,

[0081] - a second shaft section 24 centered on the X axis and comprising a second set of teeth frustoconical 24a extending around the X axis, this second section 24 being rotationally fixed to the solar 11, and

[0082] - at least one pinion 26 comprising at least one first meshing tooth 26a with the first toothing 22a of the first section 22 and the second toothing 24a of the second section 24.

[0083] The first and second sections 22, 24 are rotationally fixed to the housing 42 of the casing 20', this housing 42 carries the pinions 26, 28 and is mounted free to rotate vis-à-vis the stator 5 of the turbomachine 10'.

[0084] For this purpose, the first and second sections 22, 24 may include grooves engaged in complementary grooves of the housing 42, in place of the bearings 34, 36 mentioned above.

[0085] Thus, the housing 42 will be driven in rotation by the shaft 3, and consequently the gears 26, 28 will follow the rotation of the assembly. There is no meshing.

[0086] It is worth noting that the housing 42 can retain the aforementioned tabs 34a, 36a, and 38a. Depending on the type of turbomachine 10 or 10', it will then be decided whether these tabs are attached to the stator 5 or not. This allows for a single reference number to be used for the housing 42.

[0087] Figures 9 to 12 illustrate alternative embodiments of the gear housing 20, 20' which can be used in the context of the turbomachine 10 or the turbomachine 10'.

[0088] In the case of [Fig. 9], the pinion 26 has a rotation axis Z that is inclined with respect to the X axis. It is understood here that the number of teeth on the toothed section 24a is greater than the number of teeth on the toothed section 22a, and therefore that the sections 22 and 24 cannot rotate at the same speed. If it is desired that they rotate at the same speed, it is then necessary to provide two separate toothed sections on the pinion 26, as illustrated in [Fig. 13]. The pinion 26 includes a first frustoconical toothing 26a meshed with the toothing 22a of the section 22, and another first frustoconical toothing 26b meshed with the toothing 24a of the section 24. It is then possible to provide as many teeth on the toothing 22a as teeth on the toothing 24a so that the sections 22, 24 rotate at the same speed.

[0089] In [Fig. 12], the housing 20 is similar to that of [Fig. 7] and comprises two diametrically opposed pinions 26, 28. Each of the pinions 26, 28 is guided in rotation by a guide bearing 38, called the third bearing, which is here of the roller bearing type and in particular a double-row ball bearing. Each of the bearings 38 is interposed between the teeth of the pinion guided by this bearing and the X-axis, so as to save space.

Claims

Demands

1. Turbomachine (10) for an aircraft, said turbomachine (10) comprising a gas generator having at least one compressor (la, 1b), a combustion chamber (le) and at least one turbine (Id, le), said at least one turbine (Id, le) having a shaft (3) connected by a mechanical reduction gear (6) to a propulsion propeller (S), the reduction gear (6) having a sun gear (11) coupled to the shaft (3), a ring gear (14) extending around the sun gear (11), and satellites (12) which are meshed respectively with the sun gear (11) and the ring gear (14) and which are carried by a satellite carrier (13), characterized in that the shaft (3) is coupled to the sun gear (11) by a reversing gearbox (20) with the same rotational speed such that a rotation of the shaft (3) about its axis (X) at a given speed causes a rotation in the opposite direction of the sun (11) around the same axis (X) at the same speed.

2. Turbomachine (10) according to claim 1, wherein the gear case (20) comprises: - a first shaft section (22) centered on said axis (X) and having a first frustoconical toothing (22a) extending around the axis (X), this first section (22) being rotationally fixed to said shaft (3), - a second shaft section (24) centered on said axis (X) and having a second frustoconical toothing (24a) extending around the axis (X), this second section (24) being rotationally fixed to said sun gear (11), and - at least one first frustoconical pinion (26) having at least one first toothing (26a, 26b) meshed with the first toothing (22a) of the first section (22) and the second toothing (24a) of the second section (24).

3. Turbomachine (10) according to claim 2, wherein said first shaft section (22) is formed in one piece with said shaft (3), or is coupled to said shaft (3) by splines (30).

4. Turbomachine (10) according to claim 2 or 3, wherein said second shaft section (24) is formed in one piece with said solar (11), or is coupled to said solar (11) by splines (32).

5. Turbomachine (10) according to any one of claims 2 to 4, wherein said pinions (26, 28) comprise a second pinion (28) comprising a second toothing (28a) meshed with the first toothing (22a) of the first section (22) and the second toothing (24a) of the second section (24).

6. Turbomachine according to any one of claims 2 to 5, wherein the first pinion (26), or each of the first and second pinions (26, 28), has an axis of rotation (Z) perpendicular to said axis.

7. Turbomachine (10) according to claim 6, wherein said first and second gears (22a, 24a) of first and second sections (22, 24) have the same number of teeth.

8. Turbomachine according to any one of claims 2 to 5, wherein the first pinion (26), or each of the first and second pinions (26, 28), has an axis of rotation (Z) inclined with respect to said axis (X).

9. Turbomachine (10) according to claim 8, wherein the first and second gear teeth (22a, 24a) of the first and second sections (22, 24) have a different number of teeth.

10. Turbomachine (10) according to claim 2 to 9, wherein: - the first section (22) is guided by a first guide bearing (34) extending around the first section (22), - the second section (24) is guided by a second guide bearing (36) extending around the second section (24), and - the pinion or each pinion (26, 28) is guided by at least one third guide bearing (38) extending around the pinion (26, 28).

11. Turbomachine (10) according to claim 10, wherein the guide bearings (34, 36, 38) are rolling bearings and in particular double row ball bearings.

12. Turbomachine (10) according to claim 10 or 11, wherein said at least one third bearing (38) is interposed between the teeth (26a, 28a) of the pinion (26, 28) guided by said bearing and said shaft (X).

13. Turbomachine according to any one of claims 10 to 12, wherein the bearings (34, 36, 38) comprise outer rings having lugs (34a, 36a, 38a) or external flanges for attachment to a housing (42).

14. Turbomachine (10) according to claim 13, wherein the housing (42) is fixed to a stator (5) of the turbomachine.

15. Aircraft comprising at least two turbomachines (10, 10'), each turbomachine (10, 10') comprising a gas generator comprising at least one compressor (la, 1b), one combustion chamber (le) and at least one turbine (Id, le), said at least one turbine (Id, le) comprising a shaft (3) connected by a mechanical reduction gear (6) to a propulsion propeller (S), the reduction gear (6) comprising a solar element (11) coupled to the shaft (3), a ring gear (14) extending around the solar element (11), and satellites (12) which are meshed respectively with the solar element (11) and the ring gear (14) and which are carried by a satellite carrier (13), characterized in that one of the turbomachines (10) is as defined in any one of the preceding claims, and the other of the turbomachines (10') has its shaft (3) which is coupled to the solar element (11) by a reversible, same-speed gearbox (20'), which is inactive, such that a rotation of the tree (3) around its axis (X) at a given speed causes a rotation in the same direction of the solar (11) around the same axis (X) at the same speed.

16. Aircraft according to the preceding claim, wherein the inactive housing (20') comprises: - a first shaft section (22) centered on said axis (X) and having a first frustoconical toothing (22a) extending around the axis (X), this first section (22) being rotationally fixed to said shaft (X), - a second shaft section (24) centered on said axis (X) and having a second frustoconical toothing (24a) extending around the axis (X), this second section (24) being rotationally fixed to said sun gear (11), - at least one frustoconical pinion (26, 28) having at least one first toothing (26a, 26b) meshing with the first toothing (22a) of the first section (22) and the second toothing (24a) of the second section (24), the first and second sections (22, 24) being fixed in rotation of a casing (42) of the housing (20') which carries said at least one pinion (26, 28) and which is mounted free to rotate vis-à-vis a stator (5) of the turbomachine (10').

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