ROTOR FOR AN AIRCRAFT TURBOMACHINE FAN

Abstract

The invention relates to a rotor comprising: - a disc (14), - inter-blade platforms (16), each inter-blade platform (16) being located on the outer periphery (20a) of the disc (14) between two adjacent recesses (21), each inter-blade platform (16) extending axially between an upstream end and a downstream end (23b) and comprising a composite material, each inter-blade platform (16) further comprising: - an elongated body (23) extending axially between the upstream and downstream ends (23b), and - a stud (31) located radially between the elongated body (23) and the disc (14), characterized in that the stud (31) of each inter-blade platform (16) is attached to and fixed to the elongated body (23) of each inter-blade platform (16) and bears against the disc (14), the stud (31) of each inter-blade platform (16) comprising a material Polymer. Abbreviated figure: Figure 4

Description

Title of the invention: ROTOR FOR AN AIRCRAFT TURBOMACHINE BLOWER Technical field of the invention

[0001] The invention relates to the field of aircraft turbomachine fan rotors.

[0002] The invention relates in particular to the field of blower rotors comprising each one a disc comprising inter-blade platforms made of composite material. Technical background

[0003] 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.

[0004] The blower allows the intake of an airflow which splits into a primary airflow and a secondary airflow. The primary airflow passes through a primary channel of the turbomachine while the secondary airflow is directed towards a secondary channel surrounding the primary channel.

[0005] The primary airflow is compressed within the compressors. The compressed air is then mixed with a fuel and burned within the combustion chamber. The combustion gases pass through the turbines and then escape through the nozzle, the cross-section of which allows these gases to be accelerated to generate propulsion.

[0006] The blower typically comprises a cone axially connected to a rotor via an upstream ferrule, for example.

[0007] The rotor typically comprises a disk and blades extending radially from the disk. Each blade typically comprises a radially extending blade and a root connecting it to the disk. The blade has an aerodynamic shape and thus comprises an intrados face and an extrados face connected by a leading edge and a trailing edge.

[0008] The disc is rotatable about its longitudinal axis and is centered on the longitudinal 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 further comprises recesses located on its outer periphery and regularly distributed around the longitudinal axis. Each blade root is located in a recess of the disc for attaching the blade to the disc.

[0009] The rotor further comprises inter-blade platforms regularly distributed around the longitudinal axis and located on the outer periphery of the disk between each vane. Each platform comprises 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 further presents an external surface defining the internal secondary flow and an internal surface cooperating with the disc.

[0010] Each platform may be made of metallic material. In this case, each platform may be connected to the disk by bolting. For example, each platform includes mounting lugs axially connected to mounting lugs of the disk by bolting.

[0011] Such platforms and their connection to the disk can present drawbacks. Indeed, the metallic material of the platforms and the bolted connection considerably increase the mass of the blower. Also, it has been observed that the shear forces induced by relative displacements during disk rotation or when it is stopped, or during the free rotation phases of the blower, also known as "windmilling," can lead to premature wear of the bolted connections.

[0012] In this context, it has been proposed to manufacture these inter-blade platforms from composite material. The composite material inter-blade platforms make it possible to reduce the overall weight of the blower while preserving the mechanical and aerodynamic properties of these inter-blade platforms.

[0013] These inter-blade platforms made of composite material do not have a mechanical connection with the annular body of the fan disk. In fact, these platforms cooperate with the upstream and downstream shells. In particular, during turbomachine startup, the platform rests on the upstream and downstream shells due to the generated centrifugal forces, which retains these platforms on the disk.

[0014] Although this configuration of composite material inter-blade platforms eliminates the need for bolted connections and thus prevents premature wear of these connections, it is not entirely satisfactory. Indeed, when the disk rotates, for example during turbomachine startup or free-running of the fan, there are relative displacements of the platform, which is not mechanically fixed to the disk. These relative displacements during disk rotation generate friction and therefore wear on both the platform and the rotor disk. This wear can damage the fan rotor and thus prematurely compromise its integrity.

[0015] 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 longevity of the rotor. Summary of the invention

[0016] To this end, the invention proposes a rotor for a turbomachine blower, the rotor having a longitudinal axis and comprising:

[0017] - an annular disk centered on the longitudinal axis, the disk having a annular outer periphery and alveoli located on the outer periphery of the disc and regularly distributed around the longitudinal axis, each alveolus being designed to receive a blade,

[0018] - 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:

[0019] - an elongated body extending axially between the upstream and downstream extremities, and

[0020] - a stud located radially between the elongated body and the disc.

[0021] The rotor being remarkable in that the pad of each inter-blade platform is attached and fixed to the elongated body of each inter-blade platform and is supported on the disk, the pad of each inter-blade platform comprising a polymer material.

[0022] 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.

[0023] Such a pad bears against the disk and thus constrains the inter-blade platforms against the disk. This ensures that the inter-blade platforms remain in place on the disk and therefore limits relative movement. Thanks to such a pad, friction and therefore rotor wear are reduced.

[0024] Thanks to the invention, it is therefore possible to limit the friction of the inter-blade platforms on the disc while avoiding the mechanical bolting of the inter-blade platforms which are incompatible with the inter-blade platforms made of composite material.

[0025] The invention may comprise one or more of the following features, taken individually or in combination with each other:

[0026] - the pad of each inter-blade platform is glued to the elongated body,

[0027] - the polymer material is a thermosetting material, preferably an elastomer,

[0028] - the elastomer is a polyurethane,

[0029] - the pad of each inter-blade platform has a flat internal surface in support radially on the disk, the inner surface being located in a plane parallel to the longitudinal axis,

[0030] - the pad of each inter-blade platform has an external surface bonded to the elongated body, with the external surface inclined relative to the internal surface,

[0031] - the internal and external surfaces are connected by flat radial walls extending radially,

[0032] - 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 extends radially from the perforated wall,

[0033] - the perforated wall has an increasing thickness towards the downstream end, the plot of each inter-blade platform extending radially from an area of ​​the perforated wall of greatest thickness,

[0034] - each inter-blade platform includes a configured upstream mounting bracket to cooperate with an upstream ferrule and a downstream fixing lug configured to cooperate with a downstream ferrule, the pad of each inter-blade platform being configured to constrain the upstream and downstream fixing lugs respectively against the upstream and downstream ferrules. Brief description of the figures

[0035] 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:

[0036] [Fig-1] [Fig.1] is a schematic longitudinal sectional representation of a aircraft half-turbomachine,

[0037] [Fig.2] [Fig.2] is a schematic cross-sectional representation of a fan rotor equipping the turbomachine of [Fig.1],

[0038] [Fig.3] [Fig.3] is a perspective representation of an inter-blade platform equipping the blower rotor according to the invention,

[0039] [Fig.4] [Fig.4] is a perspective representation of an inter-blade platform mounted on the blower disc according to the invention,

[0040] [Fig.5] [Fig.5] is an enlarged view of a downstream part of the inter-blade platform of [Fig.4]. Detailed description of the invention

[0041] An example of a turbomachine 1 for an aircraft is shown in [Fig. 1]. The turbomachine 1 extends around and along a longitudinal axis A.

[0042] In the present 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.

[0043] The terms “axial”, “axially”, “radial”, “radially” are defined with respect to the longitudinal axis A.

[0044] The terms "internal", "interior", "internally", "external", "exterior", "externally", are defined with respect to the distance from the longitudinal axis A along a radial axis.

[0045] 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.

[0046] 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.

[0047] The low pressure compressor 3 further includes a housing 3a comprising an inner ferrule and an outer ferrule, for example, forming an air inlet nozzle.

[0048] The blower 2 allows the aspiration of an airflow F which divides into a primary airflow Fl and a secondary airflow F2. The primary airflow Fl passes through an annular primary vein vl and the secondary airflow F2 flows into an annular secondary vein v2 surrounding the primary vein vl.

[0049] The primary airflow Fl 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, the cross-section of which allows the acceleration of these gases to generate propulsion.

[0050] The blower 2 includes a rotor 10 that is movable and 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.

[0051] The fan 2 may be of the enclosed type. The fan 2 may therefore include a fan housing 13. The fan housing 13 is annular and centered on the longitudinal axis A. It is arranged around the rotor 10. According to another example, the fan 2 may be of the unenclosed type. According to this example, the fan 2 does not include a fan housing 13 surrounding the rotor 10.

[0052] The rotor 10 typically comprises a disc 14, blades 15 and inter-blade platforms 16.

[0053] Each blade 15 extends radially and has an aerodynamic shape. Each blade 15 comprises a blade 17 extending between a head 18 and a foot 19. The blade 17 presents 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.

[0054] Advantageously, each blade 15 comprises a composite material. The composite material is an organic matrix composite, also known by the acronym CMO. 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.

[0055] According to another example, each blade 15 comprises a metallic material, for example titanium or aluminium or an alloy thereof.

[0056] As more clearly seen in [Fig. 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, by means of an upstream ferrule 14a, and the downstream face is connected to the housing 3a of the low-pressure compressor 3 by means of a downstream ferrule 14b, for example. The disc 14 further has an outer periphery 20a and a radially opposed inner periphery 20b.

[0057] The disc 14 comprises cavities 21 regularly distributed around the longitudinal axis A. The cavities 21 are formed on the outer periphery 20a of the disc 14. Each cavity 21 opens onto the outer periphery 20a of the disc 14. Thus, each cavity 21 receives the foot 19 of a blade 15 to retain the blade 15 on the disc 14. The cavity 21 and the foot 19 cooperate, for example, by fitting.

[0058] 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.

[0059] Each cell 21 may have in cross-section a general dovetail shape or a general fir shape.

[0060] Each foot 19 has a shape complementary to the corresponding alveolus 21.

[0061] 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.

[0062] The inter-blade platforms 16 are regularly distributed around the axis Longitudinal A. The inter-blade platforms 16 are located on the outer periphery 20a of the disc 14 between two adjacent alveoli 21. Thus, each inter-blade platform 16 extends over a bulb 22 of the disc 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.

[0063] With reference to [Fig. 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.

[0064] 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 in 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.

[0065] The base 24 of each inter-blade platform 16 has an external surface 26a and an internal surface 26b radially opposed and 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 in the flow of the secondary airflow F2.

[0066] 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 and thus form 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.

[0067] The perforated wall 25 preferably has a thickness increasing towards the downstream end 23b of the inter-blade platform 16. As a result, the perforated wall 25 has a thickness el such that measured radially with respect to the longitudinal axis A at the upstream end 23a is less than a thickness e2 at the downstream end 23b.

[0068] 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.

[0069] The perforated wall 25 has an external surface 28a opposite the internal surface 26b of the base 24 and an internal surface 28b radially opposite the disk 14.

[0070] The perforated wall 25 makes it possible to stiffen and mechanically reinforce the inter-blade platforms 25. The perforated nature of this perforated wall 25 makes it possible to reduce the total 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 fixing bracket 29, 30 respectively comprises a bearing surface 29a, 30a located in a plane parallel to the longitudinal axis A.

[0073] As shown in [Fig. 4], the upstream mounting lug 29 cooperates with the upstream ferrule 14a and the downstream mounting lug 30 cooperates with the downstream ferrule 14b. Preferably, the upstream mounting lug 29 bears inside the upstream ferrule 14a and the downstream mounting lug 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.

[0074] 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.

[0075] 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.

[0076] Preferably, the stud 31 is attached to the elongated body 23 by gluing. A layer of glue (not visible) is therefore located between the stud 31 and the elongated body 23. The glue layer comprises a polymer material such as an epoxy resin.

[0077] Plot 31 comprises a polymer material.

[0078] The polymer material is preferably an elastomer. The elastomer of each pad 31 is preferably a polyurethane. Such a material provides 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.

[0079] Polyurethane advantageously has a Shore 00 hardness between 50 and 100. Polyurethane advantageously has a Shore A hardness between 20 and 80. Polyurethane advantageously has a Shore D hardness between 0 and 40. Even more advantageously, polyurethane has a Shore 88 hardness.

[0080] The elastomer can be in alveolar form, for example according to a honeycomb pattern.

[0081] According to another example, the polymer comprises an encapsulated foam.

[0082] The plot 31 has a polygonal shape. It comprises an internal surface 32 and an external surface 33 that are radially opposed. The external surface 33 faces the elongated body 23 and the internal surface 32 faces the disk 14, in particular the bulb 22.

[0083] 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.

[0084] The internal and external surfaces 32, 33 are connected together by flat walls 34 extending radially between the internal and external surfaces 32, 33.

[0085] 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 of the inter-blade platform 16 on the disk 14.

[0086] The pad 31 of each inter-blade platform 16 bears against the disc 14, specifically against the bulb 22. The pad 31 of each inter-blade platform 16 is configured to constrain the upstream and downstream mounting lugs 29, 30 respectively against the upstream and downstream ferrules 14a, 14b. This ensures that the inter-blade platforms 16 are held in place on the disc 14 and thus limits relative movement. Thanks to such a pad 31, friction and therefore wear on the rotor 10 are reduced.

[0087] Also, thanks to the stud 31 which is attached to 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 disk 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.

[0088] 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 disk (14) centered on the longitudinal axis (A), the disk (14) having an annular outer periphery (20a) and cavities (21) located on the outer periphery (20a) of the disk (14) and regularly distributed around the longitudinal axis (A), each cavity (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 cavities (21), each inter-blade platform (16) extending axially between an upstream end (23a) and a downstream end (23b) and comprising a composite material, each platform inter-blades (16) comprising among other things: - an elongated body (23) extending axially between the upstream and downstream ends (23a, 23b),and - a stud (31) located radially between the elongated body (23) and the disk (14), characterized in that the stud (31) of each inter-blade platform (16) is attached to and fixed to the elongated body (23) of each inter-blade platform (16) and rests on the disk (14), the stud (31) of each inter-blade platform (16) comprising a polymer material.

2. Rotor according to the preceding claim, characterized in that the stud (31) of each inter-blade platform (16) is bonded to the elongated body (23).

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

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

5. 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).

6. 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).

7. 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).

8. 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).

9. 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).

10. 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).

Images