Reduction gear for a turbomachine equipped with an electric generator

Abstract

A mechanical reduction gear for a turbine engine, in particular for an aircraft turbine engine, comprising: a first sun gear having a central axis forming a main axis of the reduction gear; an annular gear coaxial with the sun gear; a planet gear meshing with both the first sun gear and the annular gear; a planet carrier carrying a main shaft; and at least one electric generator comprising a first set of electromagnetic elements disposed on a first front face of the first planet gear and a second set of electromagnetic elements disposed on a first front surface of the planet carrier, the first front surface extending facing the first front face, such that the first and second sets of electromagnetic elements are disposed opposite each other, one of the first and second sets of electromagnetic elements being a first set of coils, each coil of which is wound parallel to the main axis, the other of the first and second sets of electromagnetic elements being configured to induce an electric current in the first set of coils when it is driven with a relative movement with respect to the first set of coils.

Description

Technical Field

[0001] This disclosure relates to a mechanical reduction gear for a turbine engine equipped with a generator.

[0002] Mechanical reduction gears are specifically used in aircraft turbojet engines to provide electrical power to the aircraft. However, they can also be used in any other type of turbine engine. Background Technology

[0003] New aircraft models and changes in onboard usage patterns and services tend to increase the aircraft's electrical demands. Therefore, in order to increase the electrical power supplied to the aircraft, it is necessary to increase the mechanical power extracted from the turbojet engines.

[0004] Typically, this power extraction is performed on the high-pressure (HP) shaft of the engine, especially with the aid of an auxiliary drive gearbox.

[0005] However, such extraction places a strong stress on the engine's operability, which significantly reduces its performance. Furthermore, for each engine, there exists a level beyond which mechanical energy can no longer be extracted without sacrificing normal engine operation.

[0006] Therefore, there is a real need for a device that allows for the supply of greater electrical power, which at least partially avoids the inherent disadvantages of the aforementioned known configurations. Summary of the Invention

[0007] This disclosure relates to a mechanical reduction gear for a turbine engine, particularly for a turbine engine in an aircraft, comprising: a sun gear equipped with external teeth having a central axis forming the main axis of the reduction gear; a ring gear equipped with internal teeth and coaxial with the sun gear; a planetary gear meshing with both the sun gear and the ring gear; a planetary carrier carrying a main shaft, the planetary gear being rotatably mounted about the main shaft; and at least one generator, wherein the generator includes a first set of electromagnetic elements disposed on a first front face of a first planetary gear, and a second set of electromagnetic elements disposed on a first front surface of the planetary carrier, the first front surface of the planetary carrier extending toward the first front face of the first planetary gear such that the first set of electromagnetic elements and the second set of electromagnetic elements are arranged facing each other, wherein one of the first set of electromagnetic elements and the second set of electromagnetic elements is a first set of coils, each coil in the first set of coils being wound about a direction parallel to the main axis, and wherein the other of the first set of electromagnetic elements and the second set of electromagnetic elements is configured to induce a current in the first set of coils when it is driven by relative movement relative to the first set of coils.

[0008] Therefore, this type of reduction gear can extract mechanical energy and convert it into electrical energy in a simple, efficient and compact way.

[0009] In particular, due to this axial flux configuration, the generator can be easily integrated into the typical components of a mechanical reduction gear without requiring an additional system. First, no intermediate transmission element is needed, as the generator itself is included within the reduction gear. Second, the electromagnetic components can be directly mounted on the planet carrier and planet gears, naturally moving towards the planet carrier without the need for coils around the reduction gear. This provides significant system compactness and thus maintains, or virtually maintains, the integration of the reduction gear within the turbine engine. Finally, due to this location at the interface between the planet gears and the planet carrier, the generator can benefit from the cooling system used for the planet gear bearings, eliminating the need for a specific additional cooling system.

[0010] Furthermore, since this type of reduction gear is most often connected to the low-pressure (LP) shaft of a turbocharged engine, this configuration allows mechanical energy to be extracted from the LP shaft instead of the HP shaft, thus reducing the load on the latter and ensuring better operability and performance of the turbocharged engine.

[0011] In some embodiments, the other of the first and second sets of electromagnetic elements is a first set of magnets, each of whose magnetic poles is oriented in a direction parallel to the main axis. This type of magnet naturally generates its own magnetic field without external activation, which is advantageous within the scope of rotating gears. However, in other embodiments, electromagnets are also conceivable.

[0012] In some embodiments, the sun gear, ring gear, and planetary gears are placed in the same plane. This ensures a large system capacity.

[0013] In some embodiments, the rotation of the planetary carrier is blocked. Therefore, deceleration occurs between the sun gear and the ring gear. In this type of configuration, the planetary carrier is thus fixed, which facilitates the wiring of the coils on the planetary carrier and the recovery of current generated by the generator. Specifically, the planetary carrier can be fixed to the turbine engine housing (stator).

[0014] In some embodiments, the first set of electromagnetic elements is the first set of magnets, and the second set of electromagnetic elements is the first set of coils. In practice, it is easier to mount and wire the coils onto the planetary carrier.

[0015] In some embodiments, the generator includes a third set of electromagnetic elements disposed on a second front face of the sun gear and a fourth set of electromagnetic elements disposed on a second front surface of the planet carrier, the second front surface extending toward the second front face of the sun gear. One of the third and fourth sets of electromagnetic elements is a second set of coils, each coil in which is wound about a direction parallel to the main axis. The other of the third and fourth sets of electromagnetic elements is configured to induce a current in the second set of coils when driven by relative movement relative to the second set of coils. This type of configuration allows for twice the energy extraction. Furthermore, it ensures symmetry on both sides of the planetary gear, which allows for the elimination of the resultant force of the electromagnetic forces borne by the planetary gears: thus avoiding movement of the planetary gears and / or excessive stress in their teeth.

[0016] In some embodiments, the other of the third and fourth sets of electromagnetic elements is a second set of magnets, each of which is oriented in a direction parallel to the main axis.

[0017] In some embodiments, the third set of electromagnetic elements is the second set of magnets and the fourth set of electromagnetic elements is the second set of coils.

[0018] In some embodiments, the arrangement of the second set of magnets is symmetrical to the arrangement of the first set of magnets relative to the mid-plane of the reduction gear.

[0019] In some embodiments, the configuration of the second set of coils is symmetrical to that of the first set of coils relative to the midplane of the reduction gear. This ensures symmetrical and compatible operation of the two power generation units. The forces applied to the planetary gears are further balanced.

[0020] In some embodiments, at least one set of magnets, and preferably each set of magnets, comprises a ring of multiple magnets regularly spaced along the same circle centered on the axis of rotation of the planetary gear, and all magnets are axially oriented while alternating the direction of their north poles.

[0021] In some embodiments, a space of less than 1 cm separates two consecutive magnets within the magnet ring.

[0022] In some embodiments, there is at least one group of magnets, and preferably each group of magnets includes between 10 and 60 magnets, more preferably between 12 and 48 magnets.

[0023] In some embodiments, the magnets in at least one group of magnets, and preferably in each group of magnets, are permanent magnets, preferably samarium cobalt type. In particular, samarium cobalt type magnets have a high Curie temperature, allowing them to retain their magnetization even at the operating temperature of the reduction gear.

[0024] In some embodiments, the magnets in at least one group of magnets, and preferably the magnets in each group of magnets, have a Curie temperature greater than 300°C.

[0025] In some embodiments, at least one set of coils, and preferably each set of coils, comprises a loop of multiple coils that are regularly spaced along the same circle centered on the axis of rotation of the planetary gear, with all coils wound around the axial direction.

[0026] In some embodiments, a space of less than 1 cm separates two consecutive coils within the coil loop.

[0027] In some embodiments, at least one set of coils, and preferably each set of coils, comprises three coil assemblies, with the coils of a given assembly electrically connected to each other within the same circuit. This allows for the generation of three-phase current.

[0028] In some embodiments, coils of the same coil assembly are assembled in series. This allows for higher voltages. However, parallel or mixed assemblies are also possible.

[0029] In some embodiments, the first set of coils and the second set of coils are assembled in series. In other embodiments, they may be assembled in parallel.

[0030] In some embodiments, the coil loop comprises an integer number of consecutive coil groups, each group sequentially comprising a batch of coils forming part of a first coil assembly, a batch of coils forming part of a second coil assembly, and a batch of coils forming part of a third coil assembly. This effectively allows for larger coil sizes based on smaller unit coils. In particular, each batch may include two coils. However, in other embodiments, each batch may include a single coil.

[0031] In some embodiments, at least one set of coils is included, and preferably each set of coils includes between 10 and 60 coils, more preferably between 12 and 48 coils. In particular, within a given power generation unit, the number of coils may be equal to the number of magnets; however, such equality is not required.

[0032] In some embodiments, at least one set of coils, and preferably each set of coils includes between 2 and 20 windings, more preferably between 2 and 10 windings.

[0033] In some embodiments, at least one set of coils is wound with a circular, elliptical, or triangular profile. In particular, the coils may extend primarily in the circumferential direction or in the radial direction. This allows for adjustment of the shape and placement of the magnet.

[0034] In some embodiments, at least one set of coils, and preferably each set of coils, is mounted on a collar applied to a specific front face of a particular planetary gear or a specific front surface of a planet carrier. This allows for easier coil mounting, where the coils can be assembled first to the collar, and then, subsequently, the entire collar is assembled to the planetary gear or planet carrier. This also facilitates the maintenance of the reduction gear.

[0035] In some embodiments, at least one coil in the at least one set of coils, preferably each coil, is wound around a core carried by a collar. This core, preferably a ferromagnetic core, allows a magnetic field to be guided within the coil, thereby improving energy transfer. This type of configuration also facilitates coil placement.

[0036] In some embodiments, the distance between the plane of at least one set of magnets and the plane of the facing set of coils is between 1 mm and 3 mm. Preferably, this distance range has been verified for all magnets and all coils. In effect, this air gap distance ensures good energy transfer between the magnets and coils.

[0037] In some embodiments, the planetary gears are axially blocked relative to the planet carrier. This type of blocking allows for a virtually constant air gap between the magnets and the coils, which avoids unwanted fluctuations in the current generated by the generator.

[0038] In some embodiments, the planetary gears are axially blocked relative to at least one planetary gear set, i.e., relative to the sun gear or relative to the ring gear. They may be blocked relative to the ring gear, for example, by means of herringbone teeth. This type of axial blocking allows for ensuring a virtually constant positioning of the planetary gears and thus a virtually constant positioning of the generator, which avoids undesirable fluctuations in the current generated by the generator.

[0039] In some embodiments, the power generated by the generator of the planetary gears is included in the range of 1kW to 3kW.

[0040] In some embodiments, each planetary gear is equipped with a generator. The generators of each planetary gear can be connected in series or in parallel.

[0041] This disclosure also relates to a turbine engine including a reduction gear according to any of the foregoing embodiments.

[0042] In some embodiments, the turbine engine also includes a fan and a low-pressure shaft connected to the low-pressure turbine, wherein a reduction gear is connected between the low-pressure shaft and the fan to drive the fan at a lower speed than the low-pressure shaft.

[0043] In some embodiments, the low-pressure shaft is connected to the sun gear of the reduction gear, the fan is connected to the ring gear of the reduction gear, and the planet carrier is fixed to the housing. Therefore, the planet carrier is prevented from rotating.

[0044] In this disclosure, the terms “axial,” “radial,” “tangential,” “internal,” “external,” and their derivatives are defined relative to the axis of rotation of the planetary gear set of the reduction gear; “axial plane” means a plane passing through the axis of rotation, and “radial plane” means a plane perpendicular to the axis of rotation.

[0045] The above-described features and advantages, as well as other features and advantages, will become apparent after reading the following detailed description of exemplary embodiments of the proposed reduction gear and turbine engine. This detailed description refers to the accompanying drawings. Attached Figure Description

[0046] The accompanying drawings are schematic and are primarily intended to illustrate the principles of this disclosure.

[0047] In these accompanying drawings, the same elements (or parts of elements) are labeled with the same reference numerals from one drawing to the next.

[0048] [ Figure 1 ] Figure 1 This is an axial cross-sectional view of a turbine engine based on the contents of this disclosure.

[0049] [ Figure 2 ] Figure 2 A schematic diagram of an example reduction gear is shown.

[0050] [ Figure 3 ] Figure 3 This is an axial cross-sectional view of the example reduction gear.

[0051] [ Figure 4 ] Figure 4 yes Figure 3 A perspective view of the cross section.

[0052] [ Figure 5 ] Figure 5 yes Figure 4 A magnified view of region V.

[0053] [ Figure 6 ] Figure 6 Here is another detailed image of a reduction gear example. Detailed Implementation

[0054] To make this disclosure more concrete, an example of a reduction gear is described in detail below with reference to the accompanying drawings. It should be understood that the invention is not limited to this example.

[0055] Figure 1A cross-sectional view along a vertical plane passing through its main axis A shows a dual-flow turbojet engine with a reduction gear 1 according to the present disclosure. It includes a fan 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, arranged from upstream to downstream according to the airflow cycle.

[0056] In this type of turbojet engine with a reduction gear 1, the high-pressure turbine 6 drives the high-pressure compressor 4 via a high-pressure shaft 8. The low-pressure turbine 7, also known as the fast turbine 7, drives the low-pressure compressor 3 (also known as the fast compressor) via a low-pressure shaft 9. The fast turbine 7 also drives the fan 2 via a reduction gear 10. In this way, the fan 2 can be driven at a reduced speed, which is advantageous from an aerodynamic point of view, while the low-pressure compressor 4 can be driven at a higher speed, which is advantageous from a thermodynamic point of view.

[0057] like Figure 2 As schematically shown, the reducer 10 is a planetary gear system equipped with a ring gear 11, a sun gear 12, and planetary gears 13. The planetary gears 13 are rotatably mounted on the main shaft 14 of the planet carrier 15. In the current configuration, the sun gear 12 is driven by the low-pressure shaft 9, the ring gear 11 drives the shaft 2a of the fan 2, and the planet carrier 15 is fixed.

[0058] exist Figure 3 and Figure 4 The reduction gears are shown in more detail below. It should be noted that the planet carrier 15 includes a front plate 15a and a rear plate 15b, between which five main shafts 14 extend at regular intervals. Planetary gears 13 are rotatably mounted on each main shaft 14 by means of rolling element bearings 16. The planetary gears 13 are axially blocked relative to the planet carrier 15.

[0059] Each planetary gear 13 has herringbone teeth 11a designed to mesh with the ring gear 11 and the herringbone teeth 12a of the sun gear 12. In this way, all gears 11, 12 and 13 of the reduction gear 10 are axially blocked relative to each other.

[0060] Furthermore, as from Figure 5 As can be seen more clearly, each planetary gear 13 is equipped with a generator 20. More precisely, each generator 20 includes two power generation units 20a and 20b that are symmetrically arranged on both sides of the planetary gear 13.

[0061] The first power generation unit 20a includes a first set of permanent magnets 21 and a first set of coils 22. Magnets 21, made of samarium-cobalt alloy, are mounted on the front face 13v of the planetary gear 13 so that the direction of their poles is aligned with the rotational axis B of the planetary gear 13, and thus aligned along the main axis A of the reduction gear 10 of the turbine engine 1. These magnets 21, numbered 28, are arranged along a ring gear centered on the rotational axis B of the planetary gear 13, while alternating the direction of their north poles. Therefore, on the entire circumference of the planetary gear 13, magnets 21a with their north poles pointing forward and magnets 21b with their north poles pointing backward alternately follow each other.

[0062] As in Figure 6 As can be seen more clearly, the first set of coils 22 is mounted on an annular collar 23, which is applied to the front surface 15v of the front plate 15a of the planetary carrier 15, which faces the front face 15v of the planetary gear 13. The front face 13v and the front surface 15v are parallel and both extend in the radial plane of the reduction gear: therefore, they are orthogonal to the axial direction A.

[0063] More precisely, the first group of coils 22 includes three coil components 22a, 22b, and 22c connected in series within each component, thus forming three different circuits. These coils 22, numbering 27, are arranged along a ring gear centered on the axis of rotation B of the planetary gear 13, in the order of the first component, the second component, and the third component. Therefore, the coils of the first component 22a, the second component 22b, and the third component 22c alternate one after another on the entire circumference of the collar 23.

[0064] All coils 22 are wound in a direction parallel to the axis of rotation B of the planetary gear. Furthermore, they all share the same winding direction. More precisely, in Figure 6 It is noted that the collar 23 has a protrusion 23a forming a core, on which the coil 22 is wound. The collar 23 is made of a ferromagnetic material, particularly an iron-cobalt alloy or an iron-nickel alloy.

[0065] In this example, magnet 21 and coil 22 have elliptical shapes extending in the circumferential direction, with the shape of coil 22 positioned to face magnet 21. More precisely, the loop formed by coil 22 is positioned to face the loop formed by magnet 21.

[0066] The second power generation unit 20b is exactly the same as the first power generation unit 20a—except that it is symmetrically positioned on the rear side of the planetary gear 13.

[0067] Therefore, it includes a second set of permanent magnets 26 and a second set of coils 27, which are similar to the first set of magnets 21 and the first set of coils 22, respectively. Similar to the first set of magnets 21, the magnets 26 are mounted on the rear front face 13r of the planetary gear 13. The second set of coils 27 is also mounted on an annular collar 28, which is itself applied to the front surface 15r of the rear plate 15b of the planetary carrier 15, facing the rear front face 13r of the planetary gear 13. The rear front face 13r and the rear front surface 15r are parallel and both extend in the radial plane of the reduction gear: therefore, they are orthogonal to the axial direction A.

[0068] Therefore, the second set of magnets 26 alternately includes a first magnet assembly 26a with its north pole pointing forward and a second magnet assembly 26b with its north pole pointing backward. Similarly, the second set of coils 27 alternately includes a first coil assembly 27a forming a first circuit, a second coil assembly 27b forming a second circuit, and a third coil assembly 27c forming a third circuit.

[0069] Therefore, this type of generator 20 can be equipped on each planetary gear 13. In this example, the generator 20 on each planetary gear 13 allows for the supply of 2kW of electrical power during the normal operation of the reduction gear 10. Therefore, the reduction gear can supply a total of 10kW.

[0070] Therefore, when the turbine engine 1 is operating, the planetary gear 13 rotates at high speed around its main shaft 14, while the planet carrier 15 remains stationary. Consequently, the magnets 21, 26 of each generator unit 20a, 20b pass at high speed in front of the coils 22, 27 positioned towards them, causing current to be induced into the coils 22, 27 due to the alternating orientation of the magnets 21, 26. As a result, the cable connections of the different coil assemblies 22, 27 cause each generator unit 20a, 20b to generate three-phase current at three different terminals. Two generator units 20a, 20b are then connected in series to obtain the common output of the generator 20, and then the generators 20 of each planetary gear 13 are assembled in series to obtain the common output of the entire reduction gear 10.

[0071] In this example, as already stated, magnets 21, 26 and coils 22, 27 have an elliptical shape. However, it goes without saying that magnets 21, 26 and coils 22, 27 may have other shapes depending on the specificity of the intended application—in particular, depending on the geometry of the planetary gears.

[0072] Although the invention has been described with reference to specific embodiments, it will be apparent that modifications and changes can be made to these examples without departing from the overall scope of the invention as defined by the claims. In particular, individual features of the different embodiments illustrated / mentioned may be combined in other embodiments. Therefore, the specification and drawings should be considered in an illustrative rather than restrictive sense.

[0073] It is also evident that all features described in the reference method can be transferred to the apparatus individually or in combination, and conversely, all features described in the reference apparatus can be transferred to the method individually or in combination.

Claims

1. A mechanical reduction gear for a turbine engine, comprising: A sun gear (12) equipped with external teeth (12a) has a central axis (A) forming the main axis of the mechanical reduction gear (10). A ring gear (11) equipped with internal teeth (11a), the ring gear (11) being coaxial with the sun gear (12), A planetary gear (13) meshes with both the sun gear (12) and the ring gear (11). The planetary gear (13) includes a first planetary gear (13), which includes a first front face (13v) and a second opposite front face (13r). A planetary carrier (15) supporting a main shaft (14), wherein planetary gears (13) are rotatably mounted about the main shaft (14), the planetary carrier (15) includes a front plate (15a) and a rear plate (15b), the planetary gears (13) extending between the front plate (15a) and the rear plate (15b), and At least one generator (20). wherein The generator (20) includes a first set of electromagnetic elements (21) disposed on the first front surface (13v) of the first planetary gear (13) and a second set of electromagnetic elements (22) disposed on the first front surface (15v) of the front plate (15a) of the planet carrier (15), the first front surface (15v) of the front plate (15a) of the planet carrier (15) extending towards the first front surface (13v) of the first planetary gear (13), such that the first set of electromagnetic elements (21) and the second set of electromagnetic elements (22) are arranged such that the first front surface (15v) of the front plate (15a) of the planet carrier (15) faces each other between the first front surface (13v) of the front plate (15a) of the planet carrier (15) and the first front surface (13v) of the first planetary gear (13). In this configuration, one of the first group of electromagnetic elements and the second group of electromagnetic elements is a first group of coils (22), each coil in which is wound around a direction parallel to the main axis (A). Among them, the other of the first group of electromagnetic elements and the second group of electromagnetic elements is a first group of magnets (21), each of whose magnetic poles is oriented in a direction parallel to the main axis (A) so as to induce a current in the first group of coils (22) when it is driven by relative movement relative to the first group of coils (22). The generator (20) includes a third set of electromagnetic elements (26) disposed on the second opposing front surface (13r) of the first planetary gear (13) and a fourth set of electromagnetic elements (27) disposed on the second front surface (15r) of the rear plate (15b) of the planet carrier (15). The second front surface (15r) of the rear plate (15b) of the planet carrier (15) extends towards the second opposing front surface (13r) of the first planetary gear (13), such that the third set of electromagnetic elements (26) and the fourth set of electromagnetic elements (27) are arranged so that the second front surface (15r) of the rear plate (15b) of the planet carrier (15) faces each other between the second opposing front surface (13r) of the first planetary gear (13). Among them, one of the third group of electromagnetic elements and the fourth group of electromagnetic elements is a second group of coils (27), each coil in the second group of coils (27) is wound around a direction parallel to the main axis (A), and Among them, the other of the third group of electromagnetic elements and the fourth group of electromagnetic elements is a second group of magnets (26), each of the second group of magnets (26) being oriented in a direction parallel to the main axis (A) so as to induce a current in the second group of coils (27) when it is driven by relative movement relative to the second group of coils (27).

2. The mechanical reduction gear according to claim 1, wherein the rotation of the planet carrier (15) is blocked.

3. The mechanical reduction gear according to claim 2, wherein the first set of electromagnetic elements is the first set of magnets (21), and the second set of electromagnetic elements is the first set of coils (22).

4. The mechanical reduction gear according to claim 1, wherein the arrangement of the second set of magnets (26) is symmetrical with respect to the mid-plane of the reduction gear to the arrangement of the first set of magnets (21); and The arrangement of the second set of coils (27) is symmetrical with respect to the middle plane of the reduction gear compared to the arrangement of the first set of coils (22).

5. The mechanical reduction gear of claim 1, wherein, At least one set of magnets (21) comprises a ring of multiple magnets (21a, 21b) that are regularly spaced along the same circle centered on the axis of rotation (B) of the first planetary gear (13), and all the magnets (21a, 21b) are axially oriented while alternating the directions of their north poles. At least one set of coils (22) comprises loops of multiple coils, the multiple coils being regularly spaced along the same circle centered on the axis of rotation (B) of the planetary gear (13), and all the coils of the multiple coils being wound around an axial direction. Among them, at least one set of coils (22) includes three coil assemblies (22a, 22b, 22c), and the coils of a given assembly (22a, 22b, 22c) are electrically connected to each other in the same circuit.

6. The mechanical reduction gear of claim 1, wherein, At least one set of coils (22) is mounted on a collar (23) which is applied to the front surface (13v) of the first planetary gear (13) or to the first front surface (15v) of the planet carrier (15).

7. The mechanical reduction gear according to claim 6, wherein, At least one coil of the at least one set of coils (22) is wound around a core (23a) carried by the collar (23).

8. The mechanical reduction gear according to claim 1, wherein, The distance between the plane of at least one set of magnets (21) and the plane of the facing set of coils (22) is between 1 mm and 3 mm.

9. The mechanical reduction gear according to claim 1, wherein, The planetary gear (13) is axially blocked relative to the planet carrier (15).

10. A turbine engine comprising a reduction gear (10) according to claim 1.

11. The turbine engine of claim 10, further comprising: case, Fan (2), and The low-pressure shaft (9) is connected to the low-pressure turbine (7). in, The reduction gear (10) is connected between the low-pressure shaft (9) and the fan (2) to drive the fan (2) at a lower speed than that of the low-pressure shaft (9), and The low-pressure shaft (9) is connected to the sun gear (12) of the reduction gear (10), the fan (2) is connected to the ring gear (11) of the reduction gear (10), and the planetary carrier (15) is fixed to the housing.

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