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 first shaft (3) connected by a mechanical reduction gear (6) to a propulsion propeller (S), the reduction gear (6) comprising a sun gear (11) coupled to the first shaft (3), a ring gear (14) extending around the sun gear (11) and coupled to a second shaft (4) for driving the propeller (S), 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), characterised in that the ring gear (14) is coupled to the second shaft (4) by an annular row of pinions (20).

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-A-3,611,834, US-B2-11,578,665 and CN-A-116,006,670.

[0006] The role of a mechanical reducer is to modify the speed and torque ratio between the input shaft and the output shaft of a mechanism.

[0007] Newer generations of multiflow turbomachinery, particularly those with high bypass ratios, 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 power 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 having a longitudinal axis and comprising a gas generator including at least one compressor, a combustion chamber and at least one turbine, said at least one turbine including a first shaft centered on the longitudinal axis and connected by a mechanical reduction gear to a propulsion propeller centered on the longitudinal axis, the reduction gear being centered on the longitudinal axis and including a solar element coupled to the first shaft, a ring extending around the solar element and coupled to a second propeller drive shaft, 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 crown gear is coupled to the second shaft by an annular row of gears which are distributed around the longitudinal axis and which are rotationally mobile respectively around radial axes such that a rotation of the crown gear causes a rotation of the second shaft in the opposite direction and at the same speed.

[0017] The solution proposes adding, downstream of the reducer, a row of gears which allows the direction of rotation between the crown and the propeller to be reversed.

[0018] The solution proposed below is notably compatible:

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

[0020] • of a planetary or differential gearbox,

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

[0022] • of any type of satellite carrier, whether monobloc or cage-type, and

[0023] • of any type of satellite bearing, whether it is composed of a rolling element, a hydrodynamic bearing, etc.

[0024] The turbomachine according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0025] - the gears are supported by an annular casing which at least partially surrounds the reducer;

[0026] - each of the pinions comprises a radially internal end having an external tooth coupled with a tooth of the crown and a tooth of the second shaft;

[0027] - the teeth of the crown are located on an external periphery of the crown; - the teeth of the crown are carried by an annular piece of the crown which is attached and fixed by clamping to the rest of the crown and which is guided in rotation by at least one bearing mounted around this annular piece;

[0028] - the teeth of the second tree are located at an external periphery of the tree;

[0029] - the teeth of the crown and the second shaft have the same diameter measured with respect to the longitudinal axis and / or the same number of teeth;

[0030] - the external teeth of each of the gears are conical or spiral-conical;

[0031] - each of the sprockets includes a radially external end which has a general cylindrical shape and which is surrounded by at least one guide bearing;

[0032] - the number of sprockets is greater than 10, and preferably greater than 20;

[0033] - the sprockets are separated from each other by a circumferential distance measured around the longitudinal axis, which is less than a maximum external diameter of each of the sprockets:

[0034] -- the teeth of the crown are supported by a crown holder.

[0035] The present invention also relates to an aircraft comprising at least two turbomachines, each turbomachine comprising a longitudinal axis and a gas generator comprising at least one compressor, a combustion chamber and at least one turbine, said at least one turbine comprising a first shaft centered on the longitudinal axis and connected by a mechanical reduction gear to a propulsion propeller centered on the longitudinal axis, the reduction gear being centered on the longitudinal axis and comprising a solar element coupled to the first shaft, a ring extending around the solar element and coupled to a second propeller drive shaft, 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,The other turbomachine has its ring gear directly coupled to the second shaft, so that a rotation of the ring gear causes a rotation of the second shaft in the same direction and at the same speed. Brief description of the figures:

[0036] 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:

[0037] [Fig.1] Figure 1 is a schematic view of an aircraft equipped with turbomachinery,

[0038] [Fig.2] Figure 2 is a schematic axial cross-sectional view of a turbomachine;

[0039] [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 row of gears coupling the reducer to a propeller shaft;

[0040] [Fig.4] Figure 4 is a schematic axial cross-sectional view of a reducer, a row of gears, and a propeller shaft for a turbomachine according to the invention;

[0041] [Fig. 5] Figure 5 is a larger-scale view of part of Figure 4

[0042] J

[0043] [Fig.6] Figure 6 is a schematic cross-sectional view of the reducer, the gear row and the propeller shaft of Figure 4;

[0044] [Fig.7] Figure 7 is a schematic perspective view of the reducer, the gear row and the propeller shaft of Figure 4;

[0045] [Fig.8] Figure 8 is a view similar to that of Figure 4 and illustrates a turbomachine lacking a row of gears;

[0046] [Fig.9] Figure 9 is a view similar to that of Figure 4 and shows a more concrete embodiment of the invention;

[0047] [Fig. 10] Figure 10 is a view similar to that of Figure 8 and shows a more concrete embodiment of the invention; and

[0048] [Fig. 11] Figure 11 is a schematic view of an aircraft equipped with turbomachinery,

[0049] 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 propulsion propellers of 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 propulsion propellers of the two turbomachines 10 located on each wing could rotate in opposite directions.

[0050] Figure 2 shows a turbomachine 10 which conventionally comprises a propeller or fan 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.

[0051] The propeller or blower S is driven by a propeller 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.

[0052] 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.

[0053] 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 propeller shaft 4, and downstream by seals at the level of the passage of the BP shaft 3.

[0054] 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.

[0055] In Figure 3, the reducer 6 is more clearly visible and schematically represented. The reducer is associated with an annular row of gears 20, which is located here just at the output of the reducer 6.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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 propeller shaft 4; o in a planetary configuration, as in the example shown, 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 14, which is coupled to the propeller shaft 4 by the row of gears 20. This connection can be made by a ring carrier 15, which is clamped to the ring gear 14 and coupled to the propeller shaft 4 by the row of gears 20.

[0060] Each satellite 12 is mounted to rotate freely using 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.

[0061] The particularity of the turbomachine 10 in Figure 3 is related to the fact that the row of gears 20 ensures a reversal of the direction of rotation, at the same rotational speed, of the propeller shaft 4 and therefore of the propeller S, with respect to the ring gear 14.

[0062] Figures 4 to 7 show one embodiment of the reducer 6, the row of gears 20 and the propeller shaft 4. Figure 9 shows a more concrete embodiment of these elements.

[0063] The 20 gears are distributed, preferably regularly, around the X axis. Each of the 20 gears is mobile in rotation around a radial Z axis.

[0064] The sprockets 20 are preferably supported by the annular housing 5 which surrounds at least part of the reducer 6.

[0065] Each of the pinions 20 can include a radially internal end 20a having an external tooth 22 coupled with a tooth 24 of the ring gear 14 and a tooth 26 of the propeller shaft 4. The teeth 24 and 26 extend around the X axis, and the tooth 22 extends around the Z axis.

[0066] The teeth 24 of the crown 14 are preferably located at an external periphery of the crown 14. The teeth 24 can be carried by an annular piece of the crown 14, such as the aforementioned crown carrier 15, as mentioned above.

[0067] The annular piece or the crown carrier 15 is preferably guided in rotation by at least one bearing 28 mounted around this annular piece.

[0068] Figures 4 and 9 show in particular that several bearings 28, 30, 32 can be carried by the casing 5 to which the satellite carrier 13 is connected. One or more bearings 30 allow the propeller shaft 4 to be guided and one or more bearings allow the shaft 3 coupled to the solar 11 to be guided.

[0069] The teeth 26 of the propeller shaft 4 are preferably located at an external periphery of the shaft 4.

[0070] The teeth 24, 26 preferably have the same diameter D1 measured with respect to the longitudinal axis X and / or the same number of teeth (figure 4).

[0071] The external teeth 22 of each of the pinions 20 are conical or spiral-conical in the example shown.

[0072] Each of the pinions 20 may include a radially external end 20b which has a generally cylindrical shape and which is surrounded by at least one guide bearing 34. This or these bearings 34 may also be carried by the housing 5 to which the planet carrier 13 is connected. The bearings 34 may be mounted in radial housings or recesses of the housing 5 (figures 4 and 5).

[0073] The number of sprockets (20) can be greater than 10, and is preferably greater than 20. The number of sprockets (20) can be even or odd.

[0074] The sprockets 20 are separated from each other by a circumferential distance E1 measured around the longitudinal axis X, which is less than a maximum external diameter D2 of each of the sprockets 20 (figures 6 and 7).

[0075] 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.

[0076] Each turbomachine 10 is of the type illustrated in figure 2.

[0077] 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 figures 8 and 10.

[0078] This turbomachine 10' is without a row of gears 20 at the output of the reducer 6, that is to say that its ring gear 14 is directly coupled, for example via the ring carrier 15, to the propeller shaft 4. The ring carrier 15 and the propeller shaft 4 can form a single unit, or in other words the ring carrier 15 can be integrated into the propeller shaft 4.

[0079] Thus, a rotation of the crown 14 around its X axis at a given speed causes a rotation in the same direction of the shaft 4 and the helix S around the same X axis and at the same speed.

[0080] The goal here is for the turbomachines 10, 10' to have their S propellers operating in opposite directions of rotation while having similar masses.

[0081] Figure 11 shows an aircraft comprising a central fuselage and two lateral wings, each carrying a turbomachine 10 with a twin counter-rotating propeller S1, S2. The propulsion propellers S1, S2 of one of the turbomachines 10 can rotate in the same direction as the other turbomachine, or in opposite directions.

Claims

DEMANDS 1. Turbomachine (10) for an aircraft, said turbomachine (10) having a longitudinal axis (X) and comprising a gas generator including 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 first shaft (3) centered on the longitudinal axis (X) and connected by a mechanical reduction gear (6) to a propulsion propeller (S) centered on the longitudinal axis (X), the reduction gear (6) being centered on the longitudinal axis (X) and comprising a stellar gear (11) coupled to the first shaft (3), a ring gear (14) extending around the stellar gear (11) and coupled to a second shaft (4) for driving the propeller (S), and satellites (12) which are meshed respectively with the stellar gear (11) and the ring gear (14) and which are carried by a satellite carrier (13),characterized in that the crown (14) is coupled to the second shaft (4) by an annular row of gears (20) which are distributed around the longitudinal axis (X) and which are rotationally mobile respectively around radial axes (Z) such that a rotation of the crown (14) causes a rotation of the second shaft (4) in the opposite direction and at the same speed.

2. Turbomachine (10) according to claim 1, in which the gears (20) are carried by an annular housing (5) which surrounds at least part of the reducer (6).

3. Turbomachine (10) according to claim 1 or 2, in which each of the gears (20) comprises a radially internal end (20a) having an external toothing (22) coupled with a toothing (24) of the ring (14) and a toothing (26) of the second shaft (4).

4. Turbomachine (10) according to claim 3, wherein the teeth (24) of the ring (14) are located at an external periphery of the ring (14).

5. Turbomachine (10) according to claim 3 or 4, wherein the teeth (24) of the ring gear (14) are carried by an annular part of the ring gear (14) which is attached and fixed by clamping to the rest of the ring gear (14) and which is guided in rotation by at least one bearing (28) mounted around this annular piece.

6. Turbomachine (10) according to any one of claims 3 to 5, wherein the teeth (26) of the second shaft (4) are located at an external periphery of the shaft (4).

7. Turbomachine (10) according to any one of claims 3 to 6, wherein the teeth (24, 26) of the ring (14) and of the second shaft (4) have the same diameter (D1) measured with respect to the longitudinal axis (X) and / or the same number of teeth.

8. Turbomachine (10) according to any one of claims 3 to 7, wherein the external teeth (22) of each of the gears (20) are conical or spiral-conical.

9. Turbomachine (10) according to any one of the preceding claims, wherein each of the gears (20) comprises a radially external end (20b) which has a generally cylindrical shape and which is surrounded by at least one guide bearing (34).

10. Turbomachine (10) according to any one of the preceding claims, wherein the number of gears (20) is greater than 10, and preferably greater than 20.

11. Turbomachine (10) according to any one of the preceding claims, wherein the gears (20) are separated from each other by a circumferential distance (E1) measured around the longitudinal axis (X), which is less than a maximum external diameter (D2) of each of the gears (20).

12. Aircraft comprising at least two turbomachines (10, 10'), each turbomachine (10, 10') comprising a longitudinal axis (X) and a gas generator comprising at least one compressor (1a, 1b), a combustion chamber (1c) and at least one turbine (1d, 1e), said at least one turbine (1d, 1e) comprising a first shaft (3) centered on the longitudinal axis (X) and connected by a mechanical reduction gear (6) to a propulsion propeller (S) centered on the longitudinal axis (X), the reduction gear (6) being centered on the longitudinal axis (X) and comprising a solar element (11) coupled to the first shaft (3), a ring (14) extending around the solar (11) and coupled to a second shaft (4) for driving the propeller (S), and satellites (12) which are meshed respectively with the solar (11) and the ring (14) and which are carried by a satellite carrier (13), characterized in that one of the turbomachines (10) is as defined in one of the preceding claims, and the other of the turbomachines (10') has its ring (14) which is directly coupled to the second shaft (4) so ​​that a rotation of the ring (14) causes a rotation of the second shaft (4) in the same direction and at the same speed.

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