Turbine engine for an aircraft

Abstract

The invention relates to a turbine engine (10) for an aircraft, this turbine engine (10) comprising a gas generator comprising at least one compressor (1a, 1b), a combustion chamber (1c) and at least one turbine (1d, 1e), the at least one turbine (1d, 1e) comprising a shaft (3) connected by a mechanical reduction gear (6) to a propulsion propeller (S), the shaft (3) being coupled to the sun gear (11) by a gearbox (20) with rotational direction reversal and at the same rotational speed such that a rotation of the shaft (3) about its axis (X) at a given speed causes a reverse rotation of the sun gear (11) about the same axis (X) at the same speed.

Description

[0001] DESCRIPTION

[0002] TITLE: TURBOMACHINE FOR AN AIRCRAFT

[0003] The present invention relates to the field of aircraft turbomachinery, in particular equipped with mechanical reducers.

[0004] Technical background

[0005] The technical background includes, in particular, documents US-B211,655,767 and US-A1-2023 / 130860.

[0006] 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.

[0007] Newer generations of turbofan engines, particularly those with a high bypass ratio, incorporate 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 turbine shaft into a slower rotational speed for the propeller shaft.

[0008] Such a gearbox 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 the 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 around the same operating diameter around the axis of the planet gears. These axes are parallel to the longitudinal axis of the turbomachine. Several gearbox architectures exist. In state-of-the-art turbomachinery, gearboxes are of the planetary or epicyclic type. In other similar applications, differential or compound architectures exist.- on a planetary reducer, the planet carrier is fixed and the ring forms the output shaft of the device which rotates in the opposite direction to the sun.

[0009] - on an epicyclic reducer, the ring is fixed and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the solar.

[0010] - On a differential gearbox, no element is fixed in rotation. The ring rotates in the opposite direction to the solar and satellite carrier.

[0011] Gearboxes can consist 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.

[0012] To improve the performance of an aircraft equipped with turbomachinery, it may be preferable to rotate the propeller blades in different directions from one turbomachine to another. In such solutions, and to optimize costs and industrial processes, it is necessary to minimize the number of different parts used between turbomachines.

[0013] The gearbox is a device ideally positioned in the engine to reverse the direction of rotation of the propeller without impacting the compressor and the turbine.

[0014] 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.

[0015] Summary of the invention

[0016] 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, characterized in that the shaft is coupled to the solar element by a gearbox with reversing direction of rotation and at the same speed of rotation 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.

[0017] The solution proposes adding a reversing gearbox upstream of a reduction gear; that is, a gearbox whose sole purpose is to reverse the direction of rotation. This gearbox is integrated between the input shaft and the solar cell of the reduction gear.

[0018] The solution proposed below is notably compatible:

[0019] • of a simple or multi-stage reducer;

[0020] • of an epicyclic, planetary or differential reducer,

[0021] • of straight, herringbone, helical, etc. teeth.

[0022] Advantageously, the gearbox includes:

[0023] - a first shaft section centered on said axis and comprising a first frustoconical toothing extending around the axis, this first section being rotationally fixed to said shaft,

[0024] - a second shaft section centered on said axis and comprising a second truncated conical toothing extending around the axis, this second section being rotationally fixed to said solar, and

[0025] - at least one first truncated conical pinion having a first set of teeth meshed with the first set of teeth of the first section and the second set of teeth of the second section.

[0026] The turbomachine according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0027] - 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;

[0028] - 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;

[0029] -- the first and second pinions are diametrically opposed with respect to said axis;

[0030] - the first pinion, or each of the first and second pinions, has an axis of rotation perpendicular to said axis;

[0031] - said the first and second teeth of the first and second sections have the same number of teeth;

[0032] - the first pinion, or each of the first and second pinions, has an axis of rotation inclined with respect to said axis;

[0033] - the first and second teeth of the first and second sections have a different number of teeth;

[0034] - the first section is guided by a first guiding platform extending around the first section;

[0035] - the second section is guided by a second guide bearing extending around the second section;

[0036] - the pinion or each pinion is guided by at least one third guide bearing extending around the pinion;

[0037] - the guide bearings are rolling bearings and in particular double row ball bearings;

[0038] - said at least a third bearing is interposed between the teeth of the pinion guided by this bearing and said shaft;

[0039] - the bearings include external rings with external tabs or flanges for fixing to a housing;

[0040] - the housing is attached to a stator of the turbomachine.

[0041] 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 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, 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 element 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 element around the same axis at the same speed.

[0042] Advantageously, the inactive box includes:

[0043] - a first shaft section centered on said axis and comprising a first frustoconical toothing extending around the axis, this first section being rotationally fixed to said shaft,

[0044] - a second shaft section centered on said axis and comprising a second truncated conical toothing extending around the axis, this second section being rotationally fixed to said solar,

[0045] - at least one truncated conical pinion having a first tooth meshed with the first tooth of the first section and the second tooth of the second section, 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 free to rotate vis-à-vis a stator of the turbomachine.

[0046] Brief description of the figures

[0047] 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: [Fig. 1] Figure 1 is a schematic view of an aircraft equipped with turbomachinery,

[0048] [Fig.2] Figure 2 is a schematic axial cross-sectional view of a turbomachine;

[0049] [Fig.3] Figure 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;

[0050] [Fig.4] Figure 4 is a schematic cross-sectional view of a reducer and a gear housing for a turbomachine according to the invention;

[0051] [Fig.5] Figure 5 is a schematic perspective and partial section view of the reducer and housing of Figure 4;

[0052] [Fig.6] Figure 6 is a schematic perspective view of the reducer and housing of Figure 4;

[0053] [Fig.7] Figure 7 is a schematic perspective view of an alternative embodiment of the gear housing;

[0054] [Fig.8] Figure 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;

[0055] [Fig.9] Figure 9 is a schematic cross-sectional view of a reducer and a gear housing for a turbomachine according to the invention;

[0056] [Fig.10] Figure 10 is a schematic perspective and partial section view of the reducer and housing of Figure 9;

[0057] [Fig.11] Figure 11 is a schematic perspective view of the reducer and housing of Figure 9;

[0058] [Fig. 12] Figure 12 is a schematic perspective view of an alternative embodiment of the gear housing; and

[0059] [Fig.13] Figure 13 is a schematic axial cross-sectional view of an alternative embodiment of the gear housing.

[0060] Detailed Description of the Invention 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 can rotate in a first direction of rotation, and the turbomachines 10 located on the other wing can rotate in a second direction opposite to the first. Alternatively, the two turbomachines 10 located on each wing could rotate in opposite directions.

[0061] Figure 2 shows a turbomachine 10 which conventionally comprises a fan propeller S, a low-pressure compressor 1a, a high-pressure compressor 1b, an annular combustion chamber 1c, a high-pressure turbine 1d, a low-pressure turbine 1e, and an exhaust nozzle 1h. The high-pressure compressor 1b and the high-pressure turbine 1d are connected by a high-pressure shaft 2 and together form a high-pressure (HP) unit. 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) unit.

[0062] 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.

[0063] 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, namely the planet carrier, the ring 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.

[0064] The gearbox 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 gearbox 6. This enclosure E is 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.

[0065] 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.

[0066] In Figure 3, the reducer 6 is more clearly visible and schematically represented. The reducer is associated with a gear housing 20, which is located here just at the input of the reducer 6.

[0067] 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.

[0068] Typically, the solar 11, whose axis of rotation coincides with the X axis of the turbomachine 10, drives a series of gears 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.

[0069] 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 gear 14.

[0070] At the output of the gearbox 6, we have: o in an epicyclic configuration, the set of planet gears 12 drives the planet carrier 13 in rotation around the X-axis of the turbomachine. The ring gear 14 is fixed to the motor or stator housing 5 via a ring carrier 15, and the planet carrier 13 is fixed to the fan shaft 4; o in a planetary configuration, the set of planet gears 12 is held by a planet carrier 13, which is fixed to the motor or stator housing 5. Each planet gear drives the ring gear, which is connected to the fan shaft 4 via a ring carrier 15. Each planet gear 12 is mounted to rotate freely by means of a bearing around a Y-axis. The Y-axes of rotation of the planet gears 12 are distributed around the X-axis and parallel to this X-axis.

[0071] The particularity of the turbomachine 10 in Figure 3 is related to the fact that the BP 3 shaft is coupled to the solar 11 by the gearbox 20 with reversing direction of rotation and at the same rotation 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.

[0072] Figures 4 and 5 show a more concrete example of the realization of the reducer 6 and the housing 20.

[0073] In the example shown, the gear housing 20 includes:

[0074] - a first shaft section 22 centered on the X axis and comprising a first frustoconical toothing 22a extending around the X axis, this first section 22 being rotationally fixed to the shaft BP 3,

[0075] - a second shaft section 24 centered on the X-axis and comprising a second frustoconical toothing 24a extending around the X-axis, this second section 24 being rotationally fixed to the solar element 11, and

[0076] - a first pinion 26 comprising at least a first tooth 26a meshed with the first tooth 22a of the first section 22 and the second tooth 24a of the second section 24.

[0077] 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.

[0078] 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.

[0079] As can be seen in the drawings, the axes of rotation of sections 22 and 24 are aligned with the X-axis. Regarding pinion 26, it has a Z-axis of rotation in the example shown, which is perpendicular to the X-axis. The first and second gear teeth 22a and 24a of the first and second sections 22 and 24 have the same number of teeth. These teeth can be straight, angled, etc.

[0080] The direction of rotation is reversed between the input and output of gearbox 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 its redesign. 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 advisable to "reverse" the pinion to maintain the direction of the axial forces on the teeth.

[0081] 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.

[0082] Advantageously, the guide bearings 34, 36, 38 are rolling bearings and in particular double row ball bearings as illustrated in the drawings.

[0083] Alternatively, bearings 34, 36, 38 could be smooth, for example.

[0084] The drawings show that the bearings 34, 36, 38 include external rings with tabs 34a, 36a, 38a or external flanges for fixing to a housing 42.

[0085] The housing 20 preferably includes a casing 42 which is fixed to the stator 5 of the turbomachine 10, as schematically illustrated in figure 3.

[0086] Figure 7 illustrates an alternative embodiment of the gear housing 20, which here includes a second pinion 28 comprising a second set of teeth 28a meshed with the first set of teeth 22a of the first section and the second set of teeth 24a of the second section 24. Alternatively, more than two pinions could be used. In the example shown, the pinions 26 and 28 are identical and diametrically opposed with respect to the X-axis. The Z-axis of rotation of the second pinion 28 is aligned with that of the first pinion, with the pinions 26 and 28 rotating in opposite directions.

[0087] In the context of aircraft 1 according to the invention mentioned above in relation to figure 1, this aircraft comprises at least two turbomachines 10.

[0088] Each turbomachine 10 is of the type illustrated in figure 2.

[0089] 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 figure 8.

[0090] 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 X axis at a given speed causes a rotation in the same direction of the solar 11 around the same X axis at the same speed.

[0091] The goal here is for the turbomachines 10, 10' to have their S propellers operating in opposite directions of rotation while having similar masses.

[0092] The inactive 20' housing of the 10' turbomachine may include:

[0093] - a first shaft section 22 centered on the X axis and comprising a first frustoconical toothing 22a extending around the X axis, this first section 22 being rotationally fixed to the shaft BP 3,

[0094] - a second shaft section 24 centered on the X-axis and comprising a second frustoconical toothing 24a extending around the X-axis, this second section 24 being rotationally fixed to the solar element 11, and

[0095] - at least one pinion 26 having at least one first tooth 26a meshed with the first tooth 22a of the first section 22 and the second tooth 24a of the second section 24. 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 with respect to the stator 5 of the turbomachine 10'.

[0096] For this purpose, the first and second sections 22, 24 may include splines engaged in complementary splines of the casing 42, in place of the bearings 34, 36 mentioned above.

[0097] Thus, the housing 42 will be driven in rotation by the shaft 3, and consequently the gears 26 and 28 will follow the overall rotation. There is no meshing.

[0098] It is worth noting that the housing 42 can retain the aforementioned tabs 34a, 36a, and 38a. Depending on the turbomachine type (10 or 10'), it will then be decided whether these tabs are attached to the stator 5 or not. This allows for a single part number to be used for the housing 42.

[0099] Figures 9 to 12 illustrate variant embodiments of the gear housing 20, 20' which can be used in the context of the turbomachine 10 or the turbomachine 10'.

[0100] In the case of Figure 9, the pinion 26 has a rotation axis Z that is inclined relative to the X-axis. It is clear from this that the number of teeth on the gear 24a is greater than the number of teeth on the gear 22a, and therefore that sections 22 and 24 cannot rotate at the same speed. If we want them to rotate at the same speed, it is necessary to provide two separate gear sets on the pinion 26, as illustrated in Figure 13. The pinion 26 comprises a first frustoconical gear 26a meshing with the gear 22a of section 22, and another first frustoconical gear 26b meshing with the gear 24a of section 24. It is then possible to provide the same number of teeth on the gear 22a as on the gear 24a so that sections 22 and 24 rotate at the same speed.

[0101] In Figure 12, the housing 20 is similar to that of Figure 7 and comprises two diametrically opposed gears 26, 28. Each of the gears 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 of balls. Each of the bearings 38 is interposed between the teeth of the gear 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 (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 reduction gear (6) having a sun gear (11) coupled to the shaft (3), a ring gear (14) extending around the sun gear (11), and planet gears (12) which are meshed respectively with the sun gear (11) and the ring gear (14) and which are carried by a planet carrier (13), the shaft (3) being coupled to the sun gear (11) by a reversible 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 to the sun (11) around the same axis (X) at the same speed, characterized in that the gear case (20) comprises: - a first shaft section (22) centered on said axis (X) and comprising 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 comprising a second frustoconical toothing (24a) extending around the axis (X), this second section (24) being rotationally fixed to said sun (11), and - at least one first truncated conical pinion (26) comprising 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).

2. Turbomachine (10) according to claim 1, 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).

3. Turbomachine (10) according to claim 1 or 2, 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).

4. Turbomachine (10) according to any one of claims 1 to 3, wherein the gear case (20) comprises 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).

5. Turbomachine according to claim 4, in which each of the first and second gears (26, 28) has an axis of rotation (Z) perpendicular to said axis (X) of the shaft.

6. Turbomachine according to any one of claims 1 to 3, wherein the first pinion (26) has an axis of rotation (Z) perpendicular to said axis (X) of the shaft.

7. Turbomachine (10) according to claim 5 or 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 claim 4, wherein each of the first and second pinions (26, 28) has an axis of rotation (Z) inclined with respect to said axis (X) of the shaft.

9. Turbomachine according to any one of claims 1 to 3, wherein the first pinion (26) has an axis of rotation (Z) inclined with respect to said axis (X) of the shaft.

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

11. Turbomachine (10) according to any one of claims 1 to 10, wherein: - the first section (22) is guided by a first guiding 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).

12. Turbomachine (10) according to claim 1, wherein the guide bearings (34, 36, 38) are rolling bearings and in particular double row ball bearings.

13. Turbomachine (10) according to claim 11 or 12, 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 axis (X) of the shaft.

14. Turbomachine according to any one of claims 11 to 13, wherein the bearings (34, 36, 38) comprise outer rings having lugs (34a, 36a, 38a) or external flanges for attachment to a housing (42).

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

16. Aircraft comprising at least two turbomachines (10, 10'), one of the turbomachines (10) being as defined in any one of the preceding claims, and the other 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 reduction gear (6) having 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), said other turbomachine (10') having its shaft (3) which is coupled to the solar element (11) by a gearbox (20') with reversing direction of rotation and the same rotational speed, which is inactive,so that a rotation of the shaft (3) around its axis (X) at a given speed causes a rotation in the same direction of the solar element (11) around the same axis (X) at the same speed.

17. Aircraft according to the preceding claim, in which the inactive casing (20') comprises: - a first shaft section (22) centered on said axis (X) and comprising 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 comprising a second frustoconical toothing (24a) extending around the axis (X), this second section (24) being rotationally fixed to said sun (11), - at least one frustoconical pinion (26, 28) having at least one first tooth (26a, 26b) meshed with the first tooth (22a) of the first section (22) and the second tooth (24a) of the second section (24), the first and second sections (22, 24) being rotationally fixed to a housing (42) of the casing (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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