Epicyclic gear train system for turbomachinery and turbomachinery comprising such a system

Abstract

The invention relates to a system of epicyclic gear trains for a turbomachine, comprising: i) a first epicyclic gear train (10) intended to provide a mechanical reduction function between a first shaft (9) connected to a turbine and a second shaft (14) connected to a fan, and comprising: - a sun gear (10a) connected to the first shaft, - a ring gear (10b) connected to the second shaft, - several planet gears (10c) meshing with the sun gear and the ring gear, ii) a second epicyclic gear train (20) comprising electrical machines (22) each having a rotor portion (22b) and a stator portion (22a), the rotor portions constituting a first assembly and the stator portions constituting a second assembly, one of the two assemblies being connected to the ring gear (10b) of the first gear train while the other of the two assemblies is intended to be connected to a fixed part (18b) of the turbomachine. Fig. 2.

Description

Title of the invention: Epicyclic gear train system for turbomachinery and turbomachinery comprising such a system. Technical field

[0001] The present exposition relates to an epicyclic gear train system for a turbomachine and a turbomachine comprising an epicyclic gear train system. Previous technique

[0002] Turbomachinery equipped with a reduction gear generally includes fans with a relatively slow rotational speed, or even a very slow speed in the case of a propeller engine. When an aircraft equipped with such a turbomachine is subjected to specific temperature, humidity, and speed conditions conducive to the formation of ice, the low rotational speed of the fans makes them particularly susceptible to ice buildup. Indeed, the centrifugal forces to which the fan is subjected are no longer sufficient to naturally eject the ice deposits that have formed. Consequently, a de-icing system is necessary to melt the ice accumulated on the fan.

[0003] Currently, for example, electric heating elements are mounted on the leading edges of the blower blades. When an electric current passes through these elements, heat is produced, which melts the ice accumulated on the leading edges.

[0004] The electrical power required to activate these electrical resistors is generally supplied by generators located in the turbomachine's accessory drive housing. The transmission of electrical energy from the housing of this unit to the fan rotor is, for example, achieved via brushes that rub against the rotor. However, this solution is subject to mechanical wear and lacks reliability, making it difficult to reconcile with the operating requirements of engines intended for aircraft that fly very frequently and for which minimal maintenance is desired.

[0005] There is therefore a real need to generate electricity to power heating devices for a turbomachine blower while overcoming, at least in part, the disadvantages inherent in the aforementioned prior art. Description of the invention

[0006] According to a first aspect, the present exposition relates to a system of epicyclic gear trains for a turbomachine, comprising: (i) a first epicyclic gear train intended to provide a mechanical reduction function between a first shaft connected to a turbomachine turbine and a second shaft connected to a turbomachine fan, the first epicyclic gear train comprising: -a solar pinion intended to be connected to the first turbine shaft, -a crown intended to be connected to the second blower shaft, -several satellite gears meshing, on the one hand, with the solar gear and, on the other hand, with the ring gear, ii) a second epicyclic train comprising a plurality of electrical machines, each having a rotor part and a stator part, the set of rotor parts constituting a first set and the set of stator parts constituting a second set, one of the first and second sets being connected to the ring of the first epicyclic train while the other of the first and second sets is intended to be connected to a fixed part of a turbomachine.

[0007] The aforementioned system thus makes it possible to generate electricity in the electrical machines by the simple rotation of the first epicyclic gear train, thereby making the electricity generated available at the fan rotor, thus avoiding the brush wear problems of the prior art. The electricity thus generated can then be easily transferred to the fan blades to power a defrosting heating device.

[0008] According to other possible characteristics: - the plurality of electrical machines is in a radial flux configuration with, for each electrical machine, the stator concentrically surrounding the rotor - the solar pinion of the first epicyclic train is mounted to rotate around an axis of rotation called the main axis of said first epicyclic train, the second epicyclic train being arranged adjacent to the first epicyclic train along an axial direction taken along the main axis of rotation of the first epicyclic train; - the assembly which is connected to the crown of the first epicyclic train is the assembly of parts forming stators; -each of the parts forming rotors or stators of the assembly which is intended to be connected to a fixed part of turbomachine is mounted on a satellite; - the plurality of electrical machines comprises a number n of electrical machines with n>3; - each of the parts forming rotors includes a permanent magnet rotor; - each of the parts forming stators includes a coil.

[0009] A second aspect of the exposition concerns a turbomachine comprising -a turbine connected to a first shaft called the turbine shaft, -a blower connected to a second shaft called the blower shaft, -an epicyclic gear train system for turbomachinery as briefly described above, in which the first epicyclic gear train is configured to provide a mechanical reduction function between the first turbine shaft and the second blower shaft.

[0010] According to other possible characteristics: -the second epicyclic gear train is arranged between the first epicyclic gear train and the turbomachine blower; -the fixed part of the turbomachine is a stator ring.

[0011] In the present exposition, the terms "longitudinal", "transverse", "lower", "upper" and their derivatives are defined with respect to the main direction of the blades; the terms "axial", "radial", "tangential", "inner", "outer" and their derivatives are defined with respect to the main axis of the turbomachine; "axial plane" means a plane passing through the main axis of the turbomachine and "radial plane" means a plane perpendicular to this main axis; finally, the terms "upstream" and "downstream" are defined with respect to the circulation of air in the turbomachine.

[0012] The aforementioned features and advantages, as well as others, will become apparent from the following detailed description, examples of embodiments of the epicyclic gear train system, and the turbomachine incorporating this system. This detailed description refers to the accompanying drawings. Brief description of the drawings

[0013] The attached drawings are schematic and are intended primarily to illustrate the principles of the exposition.

[0014] On these drawings, from one figure to another, identical elements (or parts of elements) are identified by the same reference signs.

[0015] [Fig-1] Fig. 1 is a schematic axial cross-sectional view of a turbomachine according to a method of implementation.

[0016] [Fig.2] The [Fig.2] represents a schematic semi-axial cross-sectional view of the upstream part of the turbomachine of the [Fig.1].

[0017] [Fig.3] [Fig.3] represents a schematic cross-sectional view of the second epicyclic gear train partially shown in [Fig.2]. Description of the implementation methods

[0018] To make the explanation more concrete, an example of a turbomachine is described in detail below, with reference to the accompanying drawings. It should be noted that the invention is not limited to this example.

[0019] Figure [1] shows, in cross-section along a vertical plane passing through its principal axis A, a turbomachine such as a turbofan engine, denoted 1, according to a mode of construction. The turbomachine comprises, from upstream to downstream according to the circulation of the air flow (from left to right in the figure), a blower 2, a low pressure compressor 3, a high pressure compressor 4, a combustion chamber 5, a high pressure turbine 6, and a low pressure turbine 7.

[0020] The blower 2 allows the aspiration of an incoming airflow to which two independent circulations are imposed, to form a primary airflow (hot flow) and a secondary airflow (cold flow).

[0021] The primary stream air can for example be compressed within the low pressure compressor 3, then the high pressure compressor 4, and then mixed with a fuel and burned within the combustion chamber 5. The gases expelled from the combustion chamber can pass through the high pressure turbine 6 and then the low pressure turbine 7 before undergoing acceleration through an ejection nozzle.

[0022] The secondary flow, for its part, bypasses the hot part of the reactor by using an annular passage which is arranged externally to the reactor core in which the primary flow circulates.

[0023] The turbomachine 1 also includes a speed reducer 10 disposed between the low pressure compressor 3 and the blower 2.

[0024] In this turbomachine, the high-pressure turbine 6 drives the high-pressure compressor 4 via a high-pressure shaft 8. The low-pressure turbine 7, also called the high-speed turbine, drives the low-pressure compressor 3, also called the high-speed compressor, via a low-pressure shaft 9. The high-speed turbine 7 also drives the blower 2 via the speed reducer 10. In this way, the blower 2 can be driven at a reduced speed, which is favorable from an aerodynamic point of view, while the low-pressure compressor 3 can be driven at a higher speed, which is favorable from a thermodynamic point of view.

[0025] Figure 2 schematically represents an enlarged axial half-section of the upstream part of the turbomachine where the fan 2 and the gearbox 10 are located. A portion of a fan blade 2 is shown, as well as a fan cone 12, which is generally integral with the fan shaft. The fan blade is connected in a known manner to the fan shaft 14 via a fan rotor or disk 16.

[0026] Fig. 2 also shows a fixed architecture forming a stator 18 to which the reducer 10 is connected.

[0027] The reducer 10 is an epicyclic gear train, called the first epicyclic gear train, intended to provide a mechanical (speed) reduction function between, on the one hand, the shaft 9 connected to the low pressure turbine 7 and, on the other hand, the shaft 14 connected to the blower 2.

[0028] The first epicyclic gear train 10 comprises, more specifically, in a known manner: - a solar or planetary pinion 10a connected to the turbine shaft 9, - a ring gear 10b (external relative to the internal central position of the pinion 10a) connected to the blower shaft 14, -several satellite pinions 10c meshing, on the one hand, with the solar pinion 10a and, on the other hand, with the ring 10b.

[0029] The satellite pinions 10c are generally arranged circumferentially around the solar pinion 10a and the ring 10b surrounds the entire set of satellite pinions 10c.

[0030] As shown in [Fig.2], the satellite gears 10c are connected to a satellite carrier 18a which is integral with the stator architecture 18 and disposed in a radially internal area of ​​this architecture.

[0031] The solar pinion 10a of the first epicyclic gear train 10 is mounted to rotate about an axis of rotation called the main axis of said first epicyclic gear train and which is represented by the axis Ap in [Fig.2]. The axis Ap is parallel to the main axis of the turbomachine.

[0032] The turbomachine also includes a second epicyclic gear train 20 disposed between the first epicyclic gear train 10 and the blower 2, in a radially internal area of ​​the stator architecture 18, which is relatively small and is not generally used.

[0033] As shown in [Fig.2], the second epicycloidal train 20 is more particularly arranged adjacent to the first epicycloidal train 10 along an axial direction taken along the main axis of rotation Ap of the first epicycloidal train 10. This axial arrangement in the unoccupied radially internal area of ​​the stator architecture 18 allows the second epicycloidal train 20 to generate a minimum of additional bulk since it is housed in an existing empty space.

[0034] The second epicyclic gear train 20 comprises, more specifically, a plurality of n electrical machines, each having a rotor portion and a stator portion. The number n of electrical machines is greater than or equal to 3. In [Fig. 2], only one electrical machine 22 is shown, with the stator portion 22a concentrically surrounding the rotor portion 22b. The plurality of electrical machines is thus in a radial flux configuration, which provides compactness to the second gear train 20. However, other configurations of electrical machines are conceivable, such as axial flux configurations.

[0035] Figure 3 illustrates the circumferential arrangement of the plurality of electrical machines 22 of the second epicyclic gear train 20 (viewed from a transverse plane), of which there are five in this example. The number of machines depends on the electrical power required for de-icing and on integration constraints (the optimum to be chosen between a given number of machines, each with a small footprint, and a smaller number of machines with a larger footprint).

[0036] In this configuration, the set of stator parts 22a of all the machines 22 is connected to the ring gear 10b of the first epicyclic gear train 10, while the set of rotor parts 22b of all these machines is connected to a fixed part of the turbomachine, in this case the stator architecture 18. More particularly, each rotor part 22b is carried by a satellite 22c (Figs. 2 and 3) which is meshed with an external stator ring gear 18b integral with the stator architecture 18. The ring gear 18b, like the satellite carrier 18a, is arranged in a radially internal area of ​​the stator architecture 18.

[0037] As shown in [Fig.2], the set of parts forming stators 22a and the ring 10b are also jointly connected to the blower shaft 14.

[0038] In this embodiment each of the rotor parts 22b comprises a permanent magnet rotor, while each of the stator parts 22a comprises an inductor coil.

[0039] In this configuration, the inductor coils are therefore mounted directly on the blower rotor, which avoids the wear and unreliability problems noted in the prior art where it was necessary to transfer electricity in a rotating reference frame.

[0040] The system formed by the two epicyclic gear trains 10 and 20, as defined above and integrated into the turbomachine of [Fig. 1], allows, through the rotation of the first train 10 (conventional reduction gear), the generation of electricity in the second train 20. The electricity thus generated is transmitted, via electrical connections 24 shown schematically as dashed lines in [Fig. 2], which run from the stator sections 22a to the blades to power, for example, the internal heating elements or any other heating / de-icing device for the blades. The arrangement of the two trains 10 and 20 one behind the other (in an axial configuration) offers a reduced and optimal footprint given the available space.

[0041] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than a restrictive sense.

Claims

Demands

1. A system of epicyclic gear trains for a turbomachine, comprising: i) a first epicyclic gear train (10) intended to provide a mechanical reduction function between a first shaft (9) connected to a turbomachine turbine and a second shaft (14) connected to a turbomachine fan, the first epicyclic gear train comprising: - a sun gear (10a) intended to be connected to the first turbine shaft, - a ring gear (10b) intended to be connected to the second fan shaft, - several planet gears (10c) meshing, on the one hand, with the sun gear and, on the other hand, with the ring gear, ii) a second epicyclic gear train (20) comprising a plurality of electrical machines (22) each comprising a rotor portion (22b) and a stator portion (22a), the set of rotor portions constituting a first set and the set of stator portions constituting a second set,one of the first and second assemblies being connected to the ring gear (10b) of the first epicyclic gear train, while the other of the first and second assemblies is intended to be connected to a fixed part (18b) of the turbomachine.

2. Epicyclic gear train system for turbomachine according to claim 1, wherein the plurality of electric machines is in a radial flux configuration with, for each electric machine, the stator concentrically surrounding the rotor.

3. Epicyclic gear train system for turbomachinery according to claim 1 or 2, wherein the sun pinion (10a) of the first epicyclic gear train (10) is mounted to rotate about an axis of rotation called the main axis (Ap) of said first epicyclic gear train, the second epicyclic gear train (20) being arranged adjacent to the first epicyclic gear train along an axial direction taken along the main axis of rotation of the first epicyclic gear train.

4. Epicyclic gear train system for turbomachine according to any one of the preceding claims, wherein the assembly which is connected to the ring (10b) of the first epicyclic gear train (10) is the assembly of parts forming stators (22a).

5. Epicyclic gear train system for turbomachine according to any one of the preceding claims, wherein each of the parts forming rotors or stators of the assembly which is intended to be connected to a fixed part (18b) of turbomachine is mounted on a satellite (22c).

6. Epicyclic gear train system for turbomachine according to any one of the preceding claims, wherein the plurality of electrical machines (22) comprises a number n of electrical machines with n>3.

7. Epicyclic gear train system for turbomachinery according to any one of the preceding claims, wherein each of the rotor-forming parts (22b) comprises a permanent magnet rotor.

8. Epicyclic gear train system for turbomachine according to any one of the preceding claims, wherein each of the stator-forming parts (22a) comprises a coil.

9. Turbomachine (1) comprising: -a turbine (7) connected to a first shaft (9) called turbine shaft, -a blower (2) connected to a second shaft (14) called blower shaft, -an epicyclic gear train system for turbomachine according to any one of the preceding claims, wherein the first epicyclic gear train (10) is configured to provide a mechanical reduction function between the first turbine shaft (9) and the second blower shaft (14).

10. Turbomachine according to the preceding claim, wherein the second epicyclic gear train (20) is arranged between the first epicyclic gear train (10) and the turbomachine blower (2).

11. Turbomachine according to claim 9 or 10, wherein the fixed part of turbomachine is a stator ring (18b).

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