Rotor for a fan of an aircraft turbine engine

Abstract

The invention relates to a rotor comprising: • - a disk (14); • - inter-vane platforms (16), each inter-vane platform (16) being located on the outer periphery (20a) of the disk (14) between two adjacent cells (21), each inter-vane platform (16) extending axially between an upstream end and a downstream end (23b) and comprising a composite material, each inter-vane platform (16) further comprising: • - an elongate body (23) extending axially between the upstream and downstream ends (23b); and • - a pad (31) located radially between the elongate body (23) and the disk (14), the pad (31) of each inter-vane platform (16) being added and attached to the elongate body (23) of each inter-vane platform (16) and bearing on the disk (14), the pad (31) of each inter-vane platform (16) comprising a polymer material, the pad (31) of each inter-vane platform (16) being bonded to the elongate body (23).

Description

[0001] DESCRIPTION

[0002] TITLE: ROTOR FOR AN AIRCRAFT TURBOMACHINE FAN

[0003] Technical field of the invention

[0004] The invention relates to the field of aircraft turbomachine fan rotors.

[0005] The invention relates in particular to the field of blower rotors each comprising a disc including inter-blade platforms made of composite material.

[0006] Technical background

[0007] The prior art is illustrated by documents US-A1-2010 / 0209253, US-A1-2015 / 125305, US-A1-2015 / 0300194, EP-B1-1046785 and FR-A1-3021694

[0008] An aircraft turbomachine typically has a longitudinal axis. It includes, for example, from upstream to downstream in the direction of gas flow along the longitudinal axis, a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, and a gas exhaust nozzle.

[0009] The blower draws in an airflow that splits into a primary airflow and a secondary airflow. The primary airflow passes through a primary duct of the turbomachine, while the secondary airflow is directed towards a secondary duct surrounding the primary duct.

[0010] The primary airflow is compressed within the compressors. The compressed air is then mixed with fuel and burned in the combustion chamber. The combustion gases pass through the turbines and then escape through the nozzle, whose cross-section accelerates these gases to generate propulsion. The fan typically consists of a cone axially connected to a rotor via an upstream ferrule, for example.

[0011] The rotor typically comprises a disk and blades extending radially from the disk. Each blade typically includes a radially extending blade and a root connecting it to the disk. The blade has an aerodynamic shape and thus comprises an upper and lower surface connected by a leading edge and a trailing edge.

[0012] The disc rotates freely about its longitudinal axis and is centered on that axis. The disc extends axially between an upstream edge and a downstream edge. The upstream edge is connected to the cone via the upstream ferrule, and the downstream edge is connected, for example, to the low-pressure compressor via a downstream ferrule. The disc also includes recesses located on its outer periphery and regularly spaced around the longitudinal axis. Each blade root is located in a recess of the disc for attaching the blade to the disc.

[0013] The rotor further comprises inter-blade platforms regularly spaced around the longitudinal axis and located on the outer periphery of the disc between each blade. Each platform includes a base extending axially between an upstream end cooperating with the upstream ferrule and a downstream end cooperating with the downstream ferrule of the low-pressure compressor. The base also has an external surface defining the internal secondary flow and an internal surface cooperating with the disc.

[0014] Each platform can be made of metallic material. In this case, each platform can be bolted to the disc. For example, each platform includes mounting brackets axially connected to disc mounting brackets by bolts.

[0015] Such platforms and their connection to the disk can present drawbacks. Indeed, the metallic material of the platforms and the bolted connections significantly increase the blower's mass. Furthermore, it has been observed that the shear forces induced by relative displacements during disk rotation or when it is stopped, or during the blower's free rotation phases, also known as "windmilling," can lead to premature wear of the bolted connections.

[0016] In this context, it was proposed to manufacture these inter-blade platforms from composite material. These composite inter-blade platforms reduce the overall weight of the fan while preserving their mechanical and aerodynamic properties. These composite inter-blade platforms do not have a mechanical connection to the annular body of the fan disk. Instead, these platforms interact with the upstream and downstream shells. Specifically, during turbomachine startup, the platform rests on the upstream and downstream shells due to the generated centrifugal forces, which retains the platforms on the disk.

[0017] Although this configuration of composite material inter-blade platforms eliminates the need for bolted connections and thus their premature wear, it is not entirely satisfactory. Indeed, when the disc rotates, for example during turbomachine startup or when the fan is running freely, the platform, which is not mechanically fixed to the disc, experiences relative displacement. This relative displacement during disc rotation generates friction, leading to wear on both the platform and the rotor disc. This wear can damage the fan rotor and prematurely compromise its integrity.

[0018] Therefore, there is a need to provide a blower rotor comprising a disc and inter-blade platforms made of composite material, the wear of which by friction is reduced in order to increase the lifespan of the rotor.

[0019] Summary of the invention: To this end, the invention proposes a rotor for a turbomachine blower, the rotor having a longitudinal axis and comprising:

[0020] - an annular disc centered on the longitudinal axis, the disc having an annular outer periphery and alveoli located on the outer periphery of the disc and regularly distributed around the longitudinal axis, each alveolus being intended to receive a blade,

[0021] - Inter-blade platforms regularly distributed around the longitudinal axis, each inter-blade platform being located on the outer periphery of the disk between two adjacent cells, each inter-blade platform extending axially between an upstream end and a downstream end and comprising a composite material, each inter-blade platform comprising, among other things:

[0022] - an elongated body extending axially between the upstream and downstream extremities, and

[0023] - a stud located radially between the elongated body and the disc.

[0024] The rotor is remarkable in that the pad of each inter-blade platform is attached and fixed to the elongated body of each inter-blade platform and rests on the disc, the pad of each inter-blade platform comprising a polymer material, the pad of each inter-blade platform being glued to the elongated body.

[0025] According to the invention, each inter-blade platform includes a stud which is attached and fixed to the elongated body of these inter-blade platforms.

[0026] This type of support rests against the disc, thus constraining the inter-blade platforms against it. This ensures the inter-blade platforms remain in place on the disc and therefore limits relative movement. Thanks to this support, friction and thus rotor wear are reduced.

[0027] Thanks to the invention, it is therefore possible to limit the friction of the inter-blade platforms on the disc while eliminating the need for bolted mechanical connections of the inter-blade platforms, which are incompatible with inter-blade platforms made of composite material. The invention may include one or more of the following features, taken individually or in combination:

[0028] - the polymer material is a thermosetting material, preferably an elastomer,

[0029] - The elastomer is a polyurethane,

[0030] - the pad of each inter-blade platform has a flat internal surface bearing radially on the disk, the internal surface being located in a plane parallel to the longitudinal axis,

[0031] - the pad of each inter-blade platform has an external surface bonded to the elongated body, the external surface being inclined relative to the internal surface,

[0032] - the internal and external surfaces are connected by flat radial walls extending radially,

[0033] - the elongated body comprises a base and a perforated wall connected to the base and extending between the upstream and downstream ends, the pad of each inter-blade platform extending radially from the perforated wall,

[0034] - the perforated wall has an increasing thickness towards the downstream end, with the pad of each inter-blade platform extending radially from an area of ​​the perforated wall of greatest thickness,

[0035] - each inter-blade platform includes an upstream fixing lug configured to cooperate with an upstream ferrule and a downstream fixing lug configured to cooperate with a downstream ferrule, the block of each inter-blade platform being configured to constrain the upstream and downstream fixing lugs respectively against the upstream and downstream ferrules.

[0036] Brief description of the figures. Other features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings in which:

[0037] [Fig.1] Figure 1 is a schematic longitudinal cross-sectional representation of half an aircraft turbomachine,

[0038] [Fig.2] Figure 2 is a schematic cross-sectional representation of a blower rotor equipping the turbomachine of Figure 1,

[0039] [Fig.3] Figure 3 is a perspective representation of an inter-blade platform equipping the blower rotor according to the invention,

[0040] [Fig. 4] Figure 4 is a perspective representation of an inter-blade platform mounted on the blower disc according to the invention,

[0041] [Fig.5] Figure 5 is an enlarged view of a downstream part of the inter-blade platform of Figure 4.

[0042] Detailed description of the invention

[0043] An example of a turbomachine 1 for an aircraft is shown in Figure 1. The turbomachine 1 extends around and along a longitudinal axis A.

[0044] In this application, the terms "upstream" and "downstream" are defined with respect to the direction of gas flow in the turbomachine 1 along the longitudinal axis A.

[0045] The terms "axial", "axially", "radial", "radially" are defined with respect to the longitudinal axis A.

[0046] The terms "internal", "interior", "internally", "external", "exterior", "externally", are defined in relation to the distance of the longitudinal axis A along a radial axis.

[0047] The turbomachine 1 is preferably a turbojet, for example a twin-spool, twin-spool turbojet. It comprises, from upstream to downstream, a fan 2, at least one compressor such as a low-pressure compressor 3 and a high-pressure compressor 4, a combustion chamber 5, at least one turbine such as a high-pressure turbine 6 and a low-pressure turbine 7, and an exhaust nozzle. The low-pressure and high-pressure compressors 3, 4 and the high-pressure and low-pressure turbines 6, 7 each comprise at least one rotor. The rotor of the low-pressure compressor 3 is connected to the rotor of the low-pressure turbine 7 by a low-pressure shaft 8, and the rotor of the high-pressure compressor 4 is connected to the rotor of the high-pressure turbine 6 by a high-pressure shaft 9. The high-pressure shaft 9 is arranged coaxially around the low-pressure shaft 8. The low-pressure and high-pressure shafts 8, 9 are centered on the longitudinal axis A.

[0048] The low pressure compressor 3 further includes a housing 3a comprising an inner ferrule and an outer ferrule for example and forming an air inlet nozzle.

[0049] The blower 2 allows the aspiration of an airflow F which divides into a primary airflow F1 and a secondary airflow F2. The primary airflow F1 passes through an annular primary vein v1 and the secondary airflow F2 flows into an annular secondary vein v2 surrounding the primary vein v1.

[0050] The primary airflow F1 is compressed within the low-pressure compressor 3 and then the high-pressure compressor 4. The compressed air is then mixed with a fuel and burned within the combustion chamber 5. The gases formed by the combustion pass through the high-pressure turbine 6 and the low-pressure turbine 7. The gases finally escape through the nozzle whose cross-section allows the acceleration of these gases to generate propulsion.

[0051] The blower 2 includes a rotor 10 that rotates about the longitudinal axis A. The blower 2 may further include a blower shaft 11 for driving the rotor 10. The blower shaft 11 is connected to the low-pressure shaft 8 via a speed reducer 12, for example.

[0052] The blower 2 may be of the enclosed type. Therefore, the blower 2 may include a blower housing 13. The blower housing 13 is annular and centered on the longitudinal axis A. It is arranged around the rotor 10. Alternatively, the blower 2 may be of the unenclosed type. In this example, the blower 2 does not include a blower housing 13 surrounding the rotor 10.

[0053] The rotor 10 typically comprises a disc 14, blades 15 and inter-blade platforms 16.

[0054] Each blade 15 extends radially and has an aerodynamic shape. Each blade 15 comprises a blade 17 extending between a tip 18 and a foot 19. The blade 17 has an aerodynamic shape and comprises an intrados face 17i and an extrados face (not visible) connected by a leading edge 17a and a trailing edge 17b.

[0055] Advantageously, each blade 15 comprises a composite material. The composite material is organic matrix composite, also known by the acronym CMC. The composite material thus comprises fibers embedded in an organic matrix. The fibers are, for example, glass, carbon, ceramic, polyester, polypropylene, or polyamide fibers. The organic matrix is, for example, selected from thermosetting polymers such as epoxy resins or thermoplastic polymers such as polyolefins.

[0056] According to another example, each blade 15 comprises a metallic material, for example titanium or aluminum or an alloy of these.

[0057] As more clearly seen in Figure 2, the disc 14 is annular and centered on the longitudinal axis A. The disc 14 extends axially between an upstream face and a downstream face. The upstream face of the disc 14 is connected to a cone (not shown), for example, via an upstream ferrule 14a, and the downstream face is connected to the housing 3a of the low-pressure compressor 3 via a downstream ferrule 14b, for example. The disc 14 also has radially opposed outer periphery 20a and inner periphery 20b.

[0058] The disc 14 comprises alveoli 21 regularly distributed around the longitudinal axis A. The alveoli 21 are formed on the outer periphery 20a of the disc 14. Each alveoli 21 opens onto the outer periphery 20a of the disc 14. Thus, each alveoli 21 receives the foot 19 of a blade 15 to retain the blade 15 on the disc 14. The alveoli 21 and the foot 19 cooperate, for example, by fitting.

[0059] Each alveolus 21 comprises in cross-section a bottom 21a and two lateral sides 21b extending radially from the bottom 21a to the outer periphery 20a of the disc 14.

[0060] Each cell 21 can have in cross-section a general dovetail shape or a general fir shape.

[0061] Each foot 19 has a shape complementary to the corresponding alveolus 21.

[0062] The disc 14 further comprises bulbs 22 regularly distributed around the longitudinal axis A. The bulbs 22 are located between two adjacent alveoli 21. Each bulb 22 has a counterform of the adjacent alveoli 21.

[0063] The inter-blade platforms 16 are regularly distributed around the longitudinal axis A. The inter-blade platforms 16 are located on the outer periphery 20a of the disk 14 between two adjacent hollows 21. Thus, each inter-blade platform 16 extends over a bulb 22 of the disk 14. Each inter-blade platform 16 is therefore located on the side of the foot 19 of the blades 15 and radially opposite the tip 18 of the blades 15.

[0064] With reference to Figure 3, each inter-blade platform 16 extends axially between an upstream end 23a and a downstream end 23b. Each inter-blade platform 16 comprises an elongated body 23 extending longitudinally between the upstream and downstream ends 23a, 23b. The elongated body 23 of each inter-blade platform 16 comprises a base 24 extending longitudinally between the upstream and downstream ends 23a, 23b and, advantageously, a perforated wall 25 extending longitudinally between the upstream and downstream ends 23a, 23b.

[0065] The elongated body 23 of each inter-blade platform 16 comprises a composite material. The composite material is preferably organic matrix. It comprises, for example, a polymer matrix and fibers embedded within the matrix. The polymer matrix comprises a thermoplastic or thermosetting polymer, for example, such as an epoxy resin. The fibers comprise, for example, glass fibers, carbon fibers, or any other type of fiber. The fibers may be woven or non-woven.

[0066] The base 24 of each inter-blade platform 16 has a radially opposed external surface 26a and internal surface 26b extending between the upstream and downstream ends 23a, 23b. The external surface 26a internally defines the secondary flow channel v2 of the secondary airflow F2. This external surface 26a thus preferably has an aerodynamic shape in order to limit disturbances to the flow of the secondary airflow F2.

[0067] The perforated wall 25 is integral with the base 24. Preferably, the perforated wall 25 and the base 24 are made from a single piece of material, thus forming a single, monolithic unit. The perforated wall 25 is connected to the internal surface 26b of the base 24. It is located opposite the disc 14 of the rotor 10 of the blower 2.

[0068] The perforated wall 25 preferably has a thickness increasing towards the downstream end 23b of the inter-blade platform 16. It follows that the perforated wall 25 has a thickness e1 such as measured radially with respect to the longitudinal axis A at the upstream end 23a less than a thickness e2 at the downstream end 23b.

[0069] The perforated wall 25 includes at least one through orifice 27. Each orifice 27 has an axis extending perpendicularly with respect to the longitudinal axis A and the radial axis. For example, the perforated wall 25 includes between one and five orifices 27 distributed along the perforated wall 25 along the longitudinal axis A. Preferably, the orifices 27 of each inter-blade platform 16 each have a different internal diameter.

[0070] The perforated wall 25 has an external surface 28a facing the internal surface 26b of the base 24 and a radially opposite internal surface 28b facing the disk 14. The perforated wall 25 provides rigidity and mechanical reinforcement to the inter-blade platforms 25. The perforated nature of this perforated wall 25 reduces the overall weight of the inter-blade platforms 16.

[0071] Each inter-blade platform 16 may further include an upstream fixing lug 29 located at the upstream end 23a of the inter-blade platform 16 and a downstream fixing lug 30 located at the downstream end 23b of the inter-blade platform 16. The upstream and downstream fixing lugs 29, 30 extend longitudinally from the elongated body 23 of each inter-blade platform 16.

[0072] Each upstream and downstream mounting bracket 29, 30 respectively comprises a bearing surface 29a, 30a situated in a plane parallel to the longitudinal axis A. As shown in Figure 4, the upstream mounting bracket 29 cooperates with the upstream ferrule 14a and the downstream mounting bracket 30 cooperates with the downstream ferrule 14b. Preferably, the upstream mounting bracket 29 bears inside the upstream ferrule 14a and the downstream mounting bracket 30 bears inside the downstream ferrule 14b. The bearing surfaces 29a, 30a thus cooperate radially with corresponding bearing surfaces of the upstream and downstream ferrules 14a, 14b.

[0073] According to the invention, each inter-blade platform 16 further comprises a stud 31 located radially between the elongated body 23 and the disc 14.

[0074] The lug 31 of each inter-blade platform 16 is attached and fixed to the elongated body 23. In particular, the lug 31 of each inter-blade platform 16 is attached and fixed to the perforated wall 25 of the elongated body 23, in particular attached and fixed to the internal surface 28b of this perforated wall 25.

[0075] Preferably, the stud 31 is attached to the elongated body 23 by bonding. A layer of adhesive (not visible) is therefore located between the stud 31 and the elongated body 23. The adhesive layer comprises a polymer material such as an epoxy resin.

[0076] Plot 31 comprises a polymer material.

[0077] The polymer material is preferably an elastomer. The elastomer of each pad 31 is preferably a polyurethane. Such a material ensures the mechanical stress of the inter-blade platforms 16 on the disc 14 while exhibiting the desired flexibility. Furthermore, the durability of the polyurethane is compatible with the rotor 10 of the blower 2. The polyurethane is, for example, commercial grade DMD5085 or grade DMD9096.

[0078] Polyurethane advantageously exhibits a Shore 00 hardness between 50 and 100. Polyurethane advantageously exhibits a Shore A hardness between 20 and 80. Polyurethane advantageously exhibits a Shore D hardness between 0 and 40. Even more advantageously, polyurethane exhibits a Shore 88 hardness.

[0079] The elastomer can be in a honeycomb shape, for example in a honeycomb pattern.

[0080] In another example, the polymer includes an encapsulated foam.

[0081] The plot 31 has a polygonal shape. It comprises an internal surface 32 and a radially opposed external surface 33. The external surface 33 faces the elongated body 23 and the internal surface 32 faces the disk 14, in particular the bulb 22.

[0082] The external surface 33 is flat. It is inclined with respect to the longitudinal axis A and therefore with respect to the internal surface 32.

[0083] The internal and external surfaces 32, 33 are connected together by flat walls 34 extending radially between the internal and external surfaces 32, 33.

[0084] The internal surface 32 is flat and extends in a plane parallel to the longitudinal axis A. The internal surface 32 forms a support surface for the inter-blade platform 16 on the disk 14.

[0085] The pad 31 of each inter-blade platform 16 rests on the disc 14, specifically on the bulb 22. The pad 31 of each inter-blade platform 16 is configured to constrain the upstream and downstream mounting lugs 29 and 30 against the upstream and downstream ferrules 14a and 14b, respectively. This ensures that the inter-blade platforms 16 remain fixed to the disc 14 and thus limits relative movement. Thanks to this pad 31, friction and therefore wear on the rotor 10 are reduced.

[0086] Also, thanks to the stud 31 which is added and fixed to the elongated body 23 of the inter-blade platform 16, the flexibility of the inter-blade platforms 16 is optimized to facilitate the mounting of the inter-blade platforms 16 on the disc 14 and the stiffness of the inter-blade platforms 16 is also optimized in order to maintain these inter-blade platforms 16 without relative displacement.

[0087] Thanks to the invention, it is therefore possible to limit the friction of the inter-blade platforms on the disc while eliminating the need for bolted mechanical connections of the inter-blade platforms, which are incompatible with inter-blade platforms made of composite material. Thanks to the invention, wear due to friction of the inter-blade platforms 16 is limited.

Claims

DEMANDS 1. Rotor (10) for a turbomachine (1) fan (2), the rotor (10) having a longitudinal axis (A) and comprising: - an annular disc (14) centered on the longitudinal axis (A), the disc (14) having an annular outer periphery (20a) and alveoli (21) located on the outer periphery (20a) of the disc (14) and regularly distributed around the longitudinal axis (A), each alveolus (21) being intended to receive a blade (15), - inter-blade platforms (16) regularly distributed around the longitudinal axis (A), each inter-blade platform (16) being located on the outer periphery (20a) of the disk (14) between two adjacent cells (21), each inter-blade platform (16) extending axially between an upstream end (23a) and a downstream end (23b) and comprising a composite material, each inter-blade platform (16) comprising, among other things: - an elongated body (23) extending axially between the upstream and downstream extremities (23a, 23b), and - a pad (31) located radially between the elongated body (23) and the disk (14), characterized in that the pad (31) of each inter-blade platform (16) is attached and fixed to the elongated body (23) of each inter-blade platform (16) and is supported on the disk (14), the pad (31) of each inter-blade platform (16) comprising a polymer material, the pad (31) of each inter-blade platform (16) being glued to the elongated body (23).

2. Rotor according to any one of the preceding claims, characterized in that the polymer material is a thermoset, preferably an elastomer.

3. Rotor according to the preceding claim, characterized in that the elastomer is a polyurethane.

4. Rotor according to any one of the preceding claims, characterized in that the pad (31) of each inter-blade platform (16) has a flat internal surface (32) bearing radially on the disk (14), the internal surface (32) being located in a plane parallel to the longitudinal axis (A).

5. Rotor according to the preceding claim, characterized in that the pad (31) of each inter-blade platform (16) has an external surface (33) bonded to the elongated body (23), the external surface (33) being inclined relative to the internal surface (32).

6. Rotor according to the preceding claim, characterized in that the internal and external surfaces (32, 33) are connected by radially extending flat radial walls (34).

7. Rotor according to any one of the preceding claims, characterized in that the elongated body (23) comprises a base (24) and a perforated wall (25) connected to the base (24) and extending between the upstream and downstream ends (23a, 23b), the pad (31) of each inter-blade platform (16) extending radially from the perforated wall (25).

8. Rotor according to the preceding claim, characterized in that the perforated wall (25) has an increasing thickness (e1, e2) towards the downstream end (23b), the pad (31) of each inter-blade platform (16) extending radially from an area of ​​the perforated wall (25) of the greatest thickness (e2).

9. Rotor according to any one of the preceding claims, characterized in that each inter-blade platform (16) comprises an upstream fixing lug (23a) configured to cooperate with an upstream ferrule (14a) and a downstream fixing lug (23b) configured to cooperate with a downstream ferrule (14b), the stud (31) of each inter-blade platform (16) being configured to constrain the upstream and downstream fixing lugs (23a, 23b) respectively against the upstream and downstream ferrules (14a, 14b).

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