Fan module comprising an improved sealing device for a lubricant chamber

Abstract

The invention relates to a turbomachine fan module (10) comprising a fan shaft (5) and a lubrication chamber (8) which is axially crossed by at least one portion of the fan shaft and which comprises at least one first bearing (6, 7) intended to support and guide the rotation of the fan shaft, the fan shaft comprising a first tubular portion (5a) closed by a cover (30), the first tubular portion comprising a distal end (23) and a proximal end (20) opposite each other along a longitudinal axis X and an annular singing chamber (25) formed in an inner surface (24) of the fan shaft between the distal end and the proximal end. According to the invention, the cover comprises a main body (31) which extends along the longitudinal axis X and is mounted in the first tubular portion to cover and sealingly close the annular singing chamber.

Description

Technical Field

[0001] This invention relates to the field of turbines. In particular, this invention relates to a fan module and a sealing device for a lubricant chamber, the fan module having a fan shaft driven by a turbine shaft via a power transmission mechanism installed in the lubricant chamber. Background Technology

[0002] Turbines (such as turbofan engines) typically include a fan positioned upstream of a gas generator, arranged according to the flow of gas within the turbine. The gas generator is housed within an annular inner casing, while the fan is housed within an annular outer casing, which is typically fixed to the nacelle. The fan drive is split into a main or hot flow and a secondary or cold flow. The main or hot flow passes through the gas generator in a main channel, while the secondary or cold flow flows around the gas generator in a secondary channel.

[0003] like Figure 1 As shown, the fan 3 of turbine 1 is possibly driven by low-pressure shaft 2 via reduction gear 4. The reduction gear is coupled to shaft 5 of fan 3, on which a fan disc is mounted, carrying the blades of fan 3. Fan shaft 5 is supported and guided by bearings comprising rolling elements (e.g., balls or rollers). The bearings and components of reduction gear 4 require continuous lubrication and cooling to ensure proper operation. A first bearing 6, a second bearing 7 on fan shaft 5, and reduction gear 4 are arranged in a single chamber 8 upstream of the turbine. The fan shaft is hollow and open at both ends. Furthermore, mounting the fan shaft to the reduction gear means that at least a portion of the interior of the fan shaft forms part of the chamber. For this purpose, chamber 8 is sealed upstream by a first cover 9, which is mounted in the fan shaft 5 at the downstream end 5P and at the first bearing 6. Chamber 8 is also closed downstream by a second cover, at least partially within the low-pressure shaft. The lubricant inlet 26, used to lubricate the bearings and reducer in the chamber, is typically located downstream of the reducer, more precisely at the housing 26a.

[0004] Another example of the arrangement of the cover upstream of the turbine fan shaft is described in detail in documents FR3013385 and WO2018 / 113332.

[0005] However, in the exemplary arrangement described above, the reducer's output shaft and fan shaft have complex geometries including shoulders, which, for example, cause lubricant (from an oil outlet) or water (originating from, for example, melted ice) to remain in certain areas of the shoulders. Retention areas positioned toward the free end of the fan shaft are particularly suitable for this type of retention. However, retention can lead to fluid imbalances (e.g., oil or water imbalances), which negatively impact the turbine's dynamic behavior.

[0006] The object of the present invention is to overcome the above-mentioned disadvantages, in particular, by providing a device for sealing an oil chamber, which enables effective lubrication of the components housed in the oil chamber while avoiding imbalance, preferably avoiding liquid imbalance (e.g., oil imbalance or water imbalance). Summary of the Invention

[0007] According to the invention, this objective is achieved by a fan module for a turbine, the fan module comprising a cylindrical fan shaft and a lubrication chamber, the cylindrical fan shaft having a longitudinal axis X and being driven to rotate by a drive shaft via a reducer, at least a portion of the fan shaft and the drive shaft axially passing through the lubrication chamber, at least a first bearing being disposed in the lubrication chamber, the first bearing being intended to support and guide the rotation of the fan shaft and the reducer, the fan shaft comprising at least one first tubular portion forming part of the chamber and being closed by a cover, the first tubular portion comprising a distal end, a proximal end, and an annular baignoire, the distal end and the proximal end being opposite each other along the longitudinal axis X, the annular baignoire being disposed in the inner surface of the fan shaft between the distal end and the proximal end, the cover comprising a body extending along the longitudinal axis X and being mounted in the first tubular section to cover and seal the annular baignoire.

[0008] Therefore, this solution enables the achievement of the aforementioned objectives. Specifically, the configuration of the cover and its arrangement within the fan shaft allow for the isolation of the vibration chamber, preventing any fluid from being introduced into it, which could potentially stagnate and cause imbalances, particularly liquid imbalances. Furthermore, this solution is simple, easy, and inexpensive to manufacture and implement.

[0009] The module also includes one or more of the following features, either individually or in combination:

[0010] - The main body has a circular cross-section, and the diameter of the main body varies between the first end and the second end.

[0011] - The body extends between a first end and a second end, the first end including a first valley that leads to the outer wall of the body and extends along its circumference, the first valley being designed to receive a first sealing element adapted to mate with the inner surface of a first tubular portion of the fan shaft.

[0012] - The second end includes a second valley that leads to the outer wall of the body and extends along its circumference. The second valley is designed to receive a second sealing element that can mate with the inner surface of the first tubular portion of the fan shaft.

[0013] - The first end is attached to the distal end of the first tubular portion, and the second end is disposed inside the first tubular portion.

[0014] - The first tubular portion includes an annular protrusion that protrudes radially inward from the fan shaft and defines a vibration chamber downstream, and the second end of the cover abuts radially against the annular protrusion.

[0015] - The second sealing element includes a flexible radial lip that is designed to abut radially against the inner surface of the first tubular portion.

[0016] - The cover has a maximum outer diameter that is smaller than the minimum inner diameter of the first tubular portion of the fan shaft.

[0017] - The cover is removably installed in the first tubular section of the fan shaft.

[0018] - The longitudinal body of the cover extends radially within the resonant cavity.

[0019] - The fan module includes a second bearing designed to support and guide the rotation of the fan shaft, and the second bearing is positioned upstream of the first bearing, with the second end of the cover close to the second bearing.

[0020] - The module includes means for axially holding a first end of a first cover at the distal end of a first tubular portion of a fan shaft, and the means is configured to axially hold the cover within the fan shaft relative to the fan shaft.

[0021] - The first and second sealing elements are arranged radially between the body of the cover and the fan shaft.

[0022] - The cover includes a threaded cylindrical hole centered on the longitudinal axis X.

[0023] The present invention also relates to a turbine that includes a fan module having the above-described features.

[0024] The present invention also relates to an aircraft comprising at least one turbine as described above. Attached Figure Description

[0025] The invention will be better understood by reading the following detailed illustrative description of the invention as a purely illustrative and non-limiting example, and with reference to the embodiments given in the accompanying drawings, in which:

[0026] [ Figure 1 ] Figure 1 A partial axial cross-section of a turbine to which the present invention is applied is shown, the turbine including a fan module upstream of a gas generator;

[0027] [ Figure 2 ] Figure 2This is a schematic diagram of a partial axial cross-section of a fan module according to the present invention, the fan module including at least one bearing and a reducer arranged in a lubrication chamber;

[0028] [ Figure 3 ] Figure 3 It is used for Figure 2 A detailed view of the integrated sealing cover of the lubrication chamber of the fan module shown;

[0029] [ Figure 4 ] Figure 4 An example of a sealing cap according to the invention is shown schematically and partially; and,

[0030] [ Figure 5 ] Figure 5 A partial axial section view is shown of another example of a cover installed upstream of the fan shaft of a fan module according to the invention. Detailed Implementation

[0031] The above has already described Figure 1 The elements described above have the same reference numerals as the same elements in the remainder of this specification.

[0032] In this invention, the terms "upstream" and "downstream" are generally defined relative to the gas flow in the turbine that is substantially parallel to the longitudinal axis X. Similarly, the terms "inner," "outer," "lower," and "upper" are defined relative to the radial axis Z perpendicular to the longitudinal axis X and relative to the distance from the longitudinal axis X.

[0033] Figure 2 A fan module 10 with a fan 3 is shown, the fan being positioned upstream of the gas generator 11 of the turbine 1. The turbine is intended to be mounted on an aircraft and is a dual-flow, dual-body type. The turbine is symmetrical about its longitudinal axis (X-axis). Of course, the invention is also applicable to other types of turbines.

[0034] Gas generator 11 includes, for example, a low-pressure compressor 12 from upstream to downstream (in... Figure 1 The components include a high-pressure compressor (not shown), a combustion chamber 11 (not shown), a high-pressure turbine (not shown), and a low-pressure turbine (not shown).

[0035] Module 10 includes a fan shaft 5 centered on a longitudinal axis X. A fan disc 3a is fitted onto the fan shaft 5. The fan includes a series of fan blades 13 extending radially outward from the fan disc 3a and defined radially by a fan housing (not shown). Specifically, each fan blade 13 includes a blade 13a, a root (not shown), and a platform 13c. The platform 13c separates the blade 13a from the root. The disc 3a includes a plurality of slots regularly distributed around the longitudinal axis, in which the root of the fan blade 13 is received. Module 10 also includes an upstream inlet cone 14 that surrounds the fan shaft 5 and forms an aerodynamic continuity with each platform 13c of the fan blade 13. Downstream, the platform 13c also has a continuous surface with the inner housing 15. The inner housing defines a radially inner wall 15a of a main channel V1 that passes through the gas generator and at least partially surrounds the reducer 4.

[0036] The fan shaft 5 is cylindrical and hollow. From upstream to downstream, the fan shaft includes: a first tubular portion 5a extending along a longitudinal axis X; a second portion forming a radial web 5b extending outward along a radial axis; and a third portion in the form of an annular shell 5c having a longitudinal axis X. The first tubular portion 5a, the radial web 5b, and the shell 5c are connected to each other by connecting radial portions. In this example, the first tubular portion 5a, the radial web 5b, and the shell 5c are integrally formed. Alternatively, the first tubular portion 5a and the radial web 5b are integral, and the shell is assembled and attached to the radial web 5b. Alternatively, the first tubular portion 5a, the radial web 5b, and the shell 5c are separate components attached together.

[0037] The fan shaft 5 is driven to rotate by the turbine's drive shaft via a power transmission mechanism that allows for a reduction in the rotational speed of the fan 3. In this example, the drive shaft is a low-pressure turbine shaft 22. The power transmission mechanism allows for the arrangement of a fan with a large diameter, which enables an increase in the bypass ratio. In this example, the fan's bypass ratio is greater than 10. Preferably, the bypass ratio is between 15 and 20.

[0038] The power transmission mechanism includes a reducer 4 formed by a gear train, referred to as a reduction gearbox (RGB). The gear train can be either planetary or rotary. Specifically, Figure 1The reducer 4 shown includes an inner center gear (referred to herein as the sun gear 16), planetary gears 17, a planet carrier 18, and an outer ring gear 19. In this example, the input of the reducer 4 is coupled to the low-pressure turbine shaft 22, while the output of the reducer 4 is coupled to the fan shaft 5. For this purpose, the reducer 4 includes an input shaft rotatably fixed to the low-pressure turbine shaft. Advantageously, the input shaft is coupled to the center gear 16, which is centered on the longitudinal axis X. The fan shaft 5 is coupled to the outer ring gear 19 via a housing 5c, which ensures that the fan shaft 5 is attached to the outer ring gear 19. A radial web 5b allows the fan shaft 5 to be adapted to the geometry of the reducer 4. The planetary gears 17 are carried by the planet carrier 18, and each planetary gear rotates about an axis substantially parallel to the longitudinal axis X. Each planetary gear in the planetary gears 18 meshes with the center gear 16 and the outer ring gear 19.

[0039] Of course, other arrangements of the reducer 4 are conceivable. For example, the output of the reducer 4 is fixed to the planet carrier 18 and the housing 5c ​​of the fan shaft. The housing 5c ​​ensures that the fan shaft 5 is attached to the planet carrier 18. The input shaft of the reducer 4 is rotatably fixed to the low-pressure turbine shaft 22 and the central gear, which is centered on the longitudinal axis X.

[0040] exist Figure 2 In this configuration, the fan shaft 5 is supported and guided to rotate by a first bearing 6, which is arranged toward the proximal end 20 of the first tubular portion 5a of the fan shaft 5. An opening defined at the proximal end 20 is defined by an annular surface having a longitudinal axis X. A radial web 5b extends from the proximal end 20 of the first tubular portion 5a. A second bearing 7 is also provided to support and guide the rotation of the fan shaft 5. The second bearing 7 is axially mounted upstream of the first bearing 6, which is arranged upstream of the reducer 4. The first portion 5a of the fan shaft 5 allows for the provision of bearing housings for the first bearing 6 and the second bearing 7. The first rolling bearing 6 and the second rolling bearing 7 each include an inner ring mounted on the outer surface 21 of the fan shaft 5 (the bearing housing of the first tubular portion 5a) and an outer ring mounted on the support housing portions 27a, 27b. The rolling element in the first bearing 6 is a ball, while the rolling element in the second bearing 7 is a roller.

[0041] like Figure 2 As shown, the fan shaft 5 extends axially between its proximal end 20 and distal end 23. The first tubular portion 5a of the fan shaft 5 has a circular cross-section. Compared to the proximal end 20 of the first tubular portion 5a, the fan shaft 5 has a reduced cross-section at its axially opposite distal end 23. Therefore, the minimum inner diameter D... 最小 It is located at the far end 23 of the fan shaft. Maximum inner diameter D 最大 It is located at the proximal end 20 of the first tubular portion 5a of the fan shaft 5.

[0042] The first tubular portion 5a also includes an inner surface 24 radially opposite to the outer surface 21. An annular baignoire 25 is disposed within this inner surface 24. Specifically, the annular baignoire extends around the entire circumference of the inner surface 24. The baignoire has a surface 25a including a bottom, the bottom defining a minimum inner diameter D greater than that located at the distal end 23. 最小 Larger diameter. Surface 25a has surface continuity with the inner surface 24 of the first tubular portion 5a. For example... Figure 2 As shown, the resonant cavity 25 is formed radially below the splines 3b1 of the fan shaft 5 and the disk 3a. Specifically, the fan shaft 5 has splines on its outer surface, which engage with complementary splines arranged on the inner surface of the disk 3a. These splines 3b1 allow the disk and fan shaft to rotate stably. The axial length of the resonant cavity 25 is approximately equal to the length of the splines 3b1.

[0043] At least bearings 6 and 7 and reducer 4 are arranged in chamber 8, through which lubricant (e.g., oil) circulates, thereby enabling lubrication and cooling of the components of bearings and reducer 4 at all times (especially during turbine operation). This ensures the proper operation of bearings 6 and 7 and reducer 4. Lubricant is supplied through lubricant inlet 26 (see...). Figure 1 At bearings 6 and 7, the bearings in the reducer, and the teeth in the reducer (planetary gears, ring gears, sun gears), and at the third bearing 28 (e.g. Figure 1 The material is injected into chamber 8 at the location shown, and the third bearing is located downstream of the reducer. The third bearing 28 supports and guides the rotation of the low-pressure shaft 2 (specifically the low-pressure turbine shaft 22). The third bearing 28 is a rolling bearing comprising an inner ring mounted on the outer surface of the low-pressure turbine shaft 22, and an outer ring mounted on a base plate fixed to the housing 26a. The rolling element of the third bearing 28 is a ball. Chamber 8 extends along the longitudinal axis X on both sides of the reducer 4.

[0044] exist Figure 2 In this configuration, at least a portion of the fan shaft 5 axially passes through the chamber 8. The low-pressure turbine shaft 22 also partially passes through the chamber 8. In other words, the fan shaft 5 and the low-pressure turbine shaft 22 extend at least partially into the chamber 8. In this example, the chamber 8 is formed at least by the cylindrical wall of the fan shaft 5 and the support shell portions 22a, 22b. More precisely, the chamber 8 is within the fan shaft and extends around the fan shaft 5.

[0045] Reference Figure 2 and Figure 3The chamber 8 also includes sealing devices for sealing the chamber 8. These sealing devices include a first removable cover 30 that seals the chamber 8 upstream. A second removable cover (not shown) is disposed downstream and also for sealing the chamber. The second cover is mounted radially inside the low-pressure turbine shaft 22 at the upstream end of the low-pressure turbine shaft. This second cover is mounted downstream of the reducer 4 and is not part of the subject matter of this invention.

[0046] Figure 3 This is a partial side view of the first cover 30. Figure 3 In this embodiment, the first cover includes a body 31 extending along axis A between a first end 32 and a second end 33. The body 31 is hollow and advantageously has a circular cross-section. The body 31 is rotationally symmetrical about axis A. In the installed configuration, axis A is coaxial with the longitudinal axis X. In this example, the outer diameter of the body 31 varies between the first end 32 and the second end 33. Advantageously, the maximum outer diameter D2 is located at the first end 32, while the minimum outer diameter D1 is located at the second end 33. The body 31 has an axially truncated conical cross-section, and the walls of the body 31 are inclined relative to axis A.

[0047] exist Figure 4 In the middle, the cover 30 includes a first valley portion 34, which extends circumferentially toward the outer wall 35 of the body. Specifically, the first valley portion 34 is supported by a first annular portion 32a, which extends radially toward the exterior of the body relative to its axis A. The first valley portion 34 has a generally U-shaped cross-section. The first valley portion is designed to receive... Figure 3 The first sealing element 36 is shown. The first sealing element 36 is capable of engaging with the inner surface 24 of the first tubular portion 5a of the fan shaft 5. The first sealing element 36 includes an annular seal. A second valley 37 is also provided in the outer wall of the main body. This second valley 37 is disposed towards the second end 33. The second valley 37 is also intended to receive a second sealing element 38, such as... Figure 3 As shown. The second sealing element 38 can mate with the inner surface 24 of the first tubular portion of the fan shaft 5. The second valley portion 37 is also supported by a second annular portion 33a, which extends radially to the outside of the body relative to the axis A of the body.

[0048] The cover 30 also has a radial wall 39 centered on the longitudinal axis X, which partially closes the first cover 30 at the second end 33 of the cover. In other words, the longitudinal body 31 rises from the radial wall 39. The radial wall 39 is generally defined in a plane perpendicular to axis A or the longitudinal axis X.

[0049] exist Figure 2In this configuration, a cover 30 is installed in the first tubular section 5a to cover and seal the annular vibration chamber 25. The cover 30 is axially mounted at the distal end 23 of the first tubular portion 5a of the fan shaft 5, and its body extends downstream within the tubular portion 5a of this first section. In particular, the cover 30 is axially located upstream of the second rolling bearing 7.

[0050] More precisely and as in Figure 3 As shown in detail, the first end 32 is attached to the distal end 23 (the free end of the fan shaft 5) of the first tubular portion 5a. Advantageously, but not limitingly, the first end 32 is securely mounted in the fan shaft 5. The outer diameter D2 of the cover 30 is less than or approximately equal to the minimum inner diameter D of the fan shaft 5 at the distal end 23. 最小 The axial retaining device 40 is arranged to hold the first end 32 of the cover 30 in an axial position relative to and inside the fan shaft 5.

[0051] exist Figure 3 In this fan shaft 5, the axial retaining device 40 includes a split annular portion 41 received in an annular groove open at the distal end 23 of the inner surface 24 of the first tubular portion 5a. The groove faces the interior of the fan shaft. The split annular portion 41 forms a retaining ring and is positioned upstream of the first end 32 of the cover 30. Similarly, the split annular portion 41 is mounted upstream of an anti-rotation pin 42, which engages in a nut 43. The nut 43 is screwed onto the distal end 23 of the second tubular portion 5a of the fan shaft 5. The nut 43 axially abuts against a shoulder on the disc 3a of the fan 3. In this way, the nut 43 enables the disc 3a to be axially secured to the fan shaft 5, and the anti-rotation pin 42 ensures, on the one hand, that the nut 43 is prevented from rotating relative to the fan shaft 5, and on the other hand, that the nut 43 is prevented from accidentally loosening.

[0052] As in Figure 3 It can also be seen that the second end 33 of the cover 30 is disposed inside the first tubular portion 5a. More specifically, the second end 33 is disposed at an annular protrusion 45 in the first tubular portion 5a. The protrusion 45 protrudes radially inward from the fan shaft 5. The protrusion 45 also defines a downstream annular resonant cavity 25. The protrusion 45 has an inner radial surface 46 that defines a minimum inner diameter D of the fan shaft 5 at the distal end 23. 最小 Smaller inner diameter D 最小2 Similarly, the outer diameter D1 of the cover 30 at the second end 33 is less than or equal to the diameter D. 最小2 In this manner, the second end 33 of the cover 30 radially abuts against the annular protrusion 45. A second sealing element 38 is also radially arranged between the protrusion 45 and the second end 33 of the cover 30. The second sealing element 38 includes an O-ring.

[0053] Reference Figure 3 and Figure 4 When the cover 30 is inserted into the fan shaft, the second end 33 of the cover can be inserted into the fan shaft inlet (distal end 23) without obstruction, and then the surface 33b of the second ring 33a (see Figure 4 ) and the surface 46 of the protrusion (see Figure 3 A flat contact occurs. The O-ring 38 collapses between the valley 37 and the surface 46. Similarly, the surface 32b of the first ring 32a (see...) Figure 4 At the inlet of the fan shaft and the inner surface of the fan shaft (see...) Figure 3 A flat contact occurs. The annular seal 36 collapses between the valley 34 and the inner surface.

[0054] In this way, the annular vibration chamber 25 is axially covered by the longitudinal body 31 of the cover 30, and the sealing elements 36, 38 installed upstream and downstream seal the vibration chamber 25. Since the lubricant is blocked by the radial wall 39, the lubricant no longer flows upstream of the fan shaft 5. Furthermore, another fluid (e.g., water from melting ice) is directly supplied to the interior of the cover 30 if it accumulates on the conical portion 14 (e.g., during icing). The inclined body 31 of the cover utilizes centrifugal force to allow the fluid to drain from the cover 30. The fluid will slide outwards on the inner wall 47 of the body, as indicated by arrow F. In other words, the vibration chamber 25 is closed by the body 31 of the cover 30 and the sealing elements 36, 38.

[0055] Figure 5 Another embodiment of the arrangement of the cover 30 in the fan shaft 5 is shown. In this example, the fan shaft 5 does not have a protrusion. The second end 33 of the cover 30 is located downstream of the resonant cavity 25. The second sealing element 38 (installed in the valley 37) includes an annular seal having an annular body 50 and a radial lip 51 extending from the body 50. The radial lip 51 is flexible. When installed, the radial lip 51 radially abuts against the inner surface 24 of the first tubular portion 5a. When the cover 30 is inserted into the fan shaft, the lip seal will be able to bend at the inlet (distal end 23) of the fan shaft and return to its shape when the lip seal has more space radially (e.g., below the spline 3b1). Unlike the flexible radial lip 51, the surface 33b of the second annular portion is located at a radial distance from the inner surface 24 of the fan shaft 5. In the first embodiment, the annular vibration cavity 25 is axially covered by the longitudinal body 31 of the cover 30, and the vibration cavity is sealed by sealing elements 36 and 38 installed upstream and downstream.

[0056] In various embodiments, and to facilitate easy removal of the first cover 30 from upstream of the fan shaft 5, the radial wall 39 of the first cover 30 includes a cylindrical bore 48 centered on the longitudinal axis X. This cylindrical bore 48 includes threads 49 designed to engage with a tool (not shown) having a threaded section. This configuration allows the first cover 30 to be held effortlessly or without obstruction.

Claims

1. A fan module (10) for a turbine (1), the fan module comprising a cylindrical fan shaft (5) of a fan (3) and a lubrication chamber (8), the cylindrical fan shaft having a longitudinal axis X and being driven to rotate by a drive shaft (22) via a reducer (4), at least a portion of the cylindrical fan shaft (5) and the drive shaft (22) axially passing through the lubrication chamber, at least one first bearing (6, 7) being disposed in the lubrication chamber, the at least one first bearing being intended to support and guide the cylindrical fan shaft (5) and the reducer. (4) Rotation, the cylindrical fan shaft (5) includes at least one first tubular portion (5a), the at least one first tubular portion forming part of the lubrication chamber (8) and being closed by a cover (30), the first tubular portion (5a) including a distal end (23), a proximal end (20) and an annular vibration cavity (25), the distal end and the proximal end being opposite each other along the longitudinal axis X, the annular vibration cavity being disposed in the inner surface (24) of the cylindrical fan shaft between the distal end (23) and the proximal end (20), characterized in that, The cover (30) includes a body (31) that extends along the longitudinal axis X and is mounted in the first tubular portion (5a) to cover and seal the annular resonant cavity (25).

2. The fan module (10) according to claim 1, characterized in that, The body (31) extends along the longitudinal axis X between a first end (32) and a second end (33), and the body has a circular cross-section, the diameter of which varies between the first end (32) and the second end (33).

3. The fan module (10) according to claim 2, characterized in that, The first end portion (32) includes a first valley (34) that leads to and extends along the circumference of the outer wall (35) of the body (31), the first valley (34) being designed to receive a first sealing element (36) that is capable of engaging with the inner surface (24) of the first tubular portion (5a) of the cylindrical fan shaft.

4. The fan module (10) according to claim 3, characterized in that, The second end (33) includes a second valley (37) that leads to and extends along the circumference of the outer wall (35) of the body (31), the second valley (37) being designed to receive a second sealing element (38) that is capable of engaging with the inner surface (24) of the first tubular portion (5a) of the cylindrical fan shaft.

5. The fan module (10) according to any one of claims 2 to 4, characterized in that, The first end (32) is attached to the distal end (23) of the first tubular portion (5a), and the second end (33) is disposed inside the first tubular portion (5a).

6. The fan module according to any one of claims 2 to 4, characterized in that, The first tubular portion (5a) includes an annular protrusion (45) that protrudes radially inward from the cylindrical fan shaft (5) and defines the annular vibration cavity (25) downstream. The second end (33) of the cover (30) abuts radially against the annular protrusion (45).

7. The fan module according to claim 4, characterized in that, The second sealing element (38) includes a flexible radial lip (51) that is designed to abut radially against the inner surface (24) of the first tubular portion (5a).

8. The fan module (10) according to any one of claims 2 to 4, characterized in that, The cover (30) has a smaller inner diameter (D) than the first tubular portion (5a) of the cylindrical fan shaft (5). 最小 Smaller maximum outer diameter (D1).

9. The fan module (10) according to any one of claims 1 to 4, characterized in that, The cover (30) is removably mounted in the first tubular portion (5a) of the cylindrical fan shaft (5).

10. The fan module according to claim 7, characterized in that, The first end (32) is attached to the distal end (23) of the first tubular portion (5a), and the second end (33) is disposed inside the first tubular portion (5a).

11. A turbine comprising a fan module according to any one of claims 1 to 10.

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