Turbine fan rotor

Abstract

The invention relates to a fan rotor (1) for a turbomachine, comprising: a fan disk (2); a fan blade (3) having a leading edge (3a) and a trailing edge (3b); platforms (4) interposed between the blades (3) and fixed to the periphery of the disk (2), each platform comprising an aerodynamic surface (4a) extending from a leading edge (3a) of the blade (3) to a trailing edge (3b) of the blade (3). The aerodynamic surface (4a) comprises an upstream longitudinal portion (40) on the side of the leading edge (3a) and a downstream longitudinal portion (41) on the side of the trailing edge (3b), the upstream longitudinal portion (40) being supported by a first member (5) of the platform (4) pivotably fixed to the disc (2), and the downstream longitudinal portion (41) being independent of the upstream longitudinal portion (40) and being supported by a second member (5) of the platform (4) pivotably fixed to the disc (2). And supported by a second member (6) of the platform (4), which is independent of the first member (5) and is pivotably fixed to the disc (2).

Description

[0001] This application is a divisional application of the patent application with application number 202080023787.7 (PCT application number PCT / FR2020 / 050600), application date March 19, 2020, and invention name “Turbine Fan Rotor”. Technical Field

[0002] The invention relates to a fan rotor for a turbomachine, advantageously but not exclusively for an aircraft. Background Art

[0003] The prior art includes in particular documents US-A1-2014 / 186187, FR-A1-3 026 794, US-B1-6416280, WO-A1-2010 / 007323 and US-A1-2015 / 125305.

[0004] Reference Figure 1 , Figure 1 A partial cross-sectional view of a fan rotor 1 is shown, which, as known from the prior art, has an axis of rotation and comprises a fan casing, a fan disk 2, fan blades 3 or blades comprising means for retaining a root which is press-fitted in a socket at the periphery of said disk 2. Each blade 3 comprises a soffit, a dorsal arch, a leading edge 3a and a trailing edge 3b.

[0005] The fan rotor 1 comprises platforms 4b inserted between the fan blades 3 and fixed to the periphery of the disk 2. Each platform 4b comprises an aerodynamic surface 4c extending substantially along said axis from the leading edge 3a to the trailing edge 3b of the blade 3, the platform 4b being mounted between the blades.

[0006] Finally, the rotor 1 comprises an upstream cone 13 , an upstream casing 14 and a downstream casing 15 , these two casings 14 , 15 being fixed to the fan disk 2 .

[0007] Such a fan rotor is known in particular from document US 2008 / 0226458.

[0008] Each platform must provide the following functions: including aerodynamic function and definition of air flow channels, aerodynamic function is the main function of the platform.

[0009] Furthermore, each platform must meet all operational conditions, namely ensuring the performance of the entire operational case (eg flight of the aircraft), ensuring safety requirements and ensuring the effectiveness of the rotor as part of an engine for commercial use.

[0010] Finally, each platform must be integrated into the environment of the rotor in such a way as to have a consistent interface at the boundaries of the stages of the fan rotor and to avoid interferences at the level of the other stages of the turbine including the fan rotor.

[0011] In recent turbomachines, the displacement of the fan blades or blades, in particular the tangential displacement of the fan blades or blades, becomes increasingly important as the diameter of the fan rotor increases.

[0012] Thus, there is a gap between the fan blades and the aerodynamic surface, which extends substantially along the axis from the leading edge of the blade to the trailing edge of the blade, between which the platform is mounted. This gap may exceed 8 mm at the trailing edge of each blade, while there is almost no gap at the leading edge of each blade.

[0013] The presence of this gap requires the installation of seals between the aerodynamic surface of the platform and each blade. However, current sealing technology is not able to bridge gaps exceeding 8 mm. Therefore, the sealing of the fan rotor assembly at the level of the connection of each blade to the platform is degraded.

[0014] The problem at the basis of the invention is therefore that of ensuring, in a fan rotor, a seal between a fan platform and each fan blade, in particular at the level of the interface of the platform with the blade trailing edge. Summary of the invention

[0015] To this end, the invention relates to a fan rotor for a turbomachine, the rotor having an axis of rotation and comprising:

[0016] - fan tray,

[0017] - fan blades comprising a root which is press-fitted into a socket at the periphery of the disk, each blade comprising a soffit, a dorsal, a leading edge and a trailing edge,

[0018] - platforms inserted between the fan blades and fixed to the periphery of the disk, each platform comprising an aerodynamic surface extending substantially along said axis from the leading edge of the blade to the trailing edge of the blade, the platforms being mounted between the blades,

[0019] Characterized in that the aerodynamic surface comprises an upstream longitudinal portion, situated on the side of the leading edge of the blade, and a downstream longitudinal portion, independent of the upstream longitudinal portion, situated on the side of the trailing edge of the blade, the upstream longitudinal portion being supported by a first member of the platform, preferably pivotably fixed to the disk, and the downstream longitudinal portion being supported by a second member of the platform, independent of the first member and fixed to the disk.

[0020] The technical effect achieved by the present invention is to enable the fan platform to follow the displacement (mainly tangential displacement) of the blades associated with the platform, in particular, to follow the displacement of the trailing edges of the blades associated with the platform.

[0021] To this end, the invention proposes to divide the aerodynamic surface of each fan platform axially into two longitudinal portions, making the downstream longitudinal portion movable so that it can follow the displacements imposed by the associated blades.

[0022] The upstream longitudinal portion of the aerodynamic surface follows the displacement of the leading edge of a fan blade associated with the platform, whereas the downstream longitudinal portion follows the displacement of the trailing edge of the fan blade.

[0023] Due to the almost zero displacement of the leading edge of the fan blade associated with the platform, the upstream longitudinal portion of the aerodynamic surface following the displacement of the leading edge is effectively blocked.More generally, however, the invention can be applied to a platform associated with two fan blades, the leading edges of which can move.

[0024] As mentioned above, excessive displacement of the trailing edge of the fan blade that the platform does not follow is the reason for the difficulties encountered in defining the platform and the seal between the two fan blades that build the platform. By implementing the present invention, and fixing the second member to the fan disk in a pivotable manner, the above problems are precisely avoided.

[0025] In order to follow the deflection of the trailing edge of the blade associated with the platform, the second member of the platform supporting the downstream longitudinal portion can be mounted on the disk, for example by pivoting connection with the fan disk, so as to have the freedom to pivot about an axis. In the embodiment to be described later, the upstream portion of the platform is designed to be fixed and mounted to the disk. However, it is conceivable that the upstream portion can also pivot like the downstream portion.

[0026] The implementation of the platform in two separate parts with two longitudinal portions, namely an upstream longitudinal portion and a downstream longitudinal portion, makes it possible to use seals that are commonly used in the technical field but which are no longer suitable for displacements of more than 8 mm between the trailing edge of the fan blade and the platform.

[0027] Advantageously, the second member is pivotably fixed to the disc.

[0028] Advantageously, the axial extent of the upstream longitudinal portion, along the axis of rotation of the rotor, is between 0.5 and 1.5 times the axial extent of the downstream longitudinal portion.

[0029] Advantageously, the second member is fixed to the disc by means of a single fixing element defining, relative to the disc, a pivot axis of the downstream longitudinal portion.

[0030] The second member is fixed to the disk with a pivotal degree of freedom to follow the deflection of the trailing edge of the fan blade associated with the platform.The simplest solution is to have a single fixed element pivoting about a fixed axis without the need for expensive, numerous and bulky devices.

[0031] Advantageously, the second member comprises a fixing bracket axially applied to the flange of the disk, the fixing bracket comprising an axial hole aligned with the axial hole of the flange, the fixing element passing through the axial hole of the fixing bracket and the axial hole of the flange.

[0032] Advantageously, the bore of the fixing bracket at least partially receives a ring through which the fixing element passes, the ring being clamped axially against the flange of the disk and being spaced apart from the fixing bracket by an axial play and a radial play.

[0033] Thus, the fixing bracket forming the second member is mounted with axial and radial play on the ring, which clamps against the disk. The diameter of the hole in the fixing bracket is greater than the diameter of the fixing element, so that a part of the ring is inserted between the fixing bracket and the fixing element.

[0034] As a result, with the ring partially inserted between the fixing bracket and the fixing element, the fixing bracket can be pivoted about the fixing element passing through the fixing bracket while remaining in position relative to the fixing element.

[0035] The portion of the ring inside the fixing bracket prevents radial movement of the fixing bracket relative to the fixing element, and the portion of the ring outside the fixing bracket abuts against axial movement of the fixing bracket relative to the fixing element.

[0036] Advantageously, the fixing element is a screw whose head rests on the face of the flange, or on the face of an insert situated on this face, and whose threaded stem receives a nut resting on the ring.

[0037] Advantageously, one of the longitudinal sections comprises, at a longitudinal end of one of the longitudinal sections situated to the side of the other of the longitudinal sections, a bearing surface for the other longitudinal section.

[0038] The platform according to the invention is not integral but comprises an upstream longitudinal portion and a downstream longitudinal portion which are independent of each other. Alternatively, the first longitudinal portion of the upstream longitudinal portion and the first longitudinal portion of the downstream longitudinal portion may comprise a bearing surface protruding from the first portion to loosely and partially support the end facing the second longitudinal portion.

[0039] Advantageously, the longitudinal portions comprise circumferential edges facing each other, said bearing surface extending along one of these edges only over a portion of the circumferential extent of this edge.

[0040] The invention relates to an aircraft turbomachine comprising such a rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other characteristics, objectives and advantages of the invention will become apparent from the following detailed description and the accompanying drawings, given by way of non-limiting example and in which:

[0042] [ Figure 1 ] Figure 1 is a schematic diagram of a partial cross-sectional view of a fan rotor according to the prior art,

[0043] [ Figure 2 ] Figure 2 is a schematic diagram of a partial perspective view of a fan rotor according to an embodiment of the invention, showing the blades and disk of the fan and a portion of a platform with an aerodynamic surface, the aerodynamic surface comprising an upstream longitudinal portion and a downstream longitudinal portion and fixing members of the upstream longitudinal portion and the downstream longitudinal portion fixed to the teeth of the fan disk, the longitudinal portion in a mounted state Figure 2 It is shown in

[0044] [ Figure 3 ] Figure 3 yes Figure 2 A schematic diagram of a perspective view of a fan rotor is shown in Figure 3 Only the upstream longitudinal part of the aerodynamic surface is shown.

[0045] [ Figure 4 ] Figure 4 yes Figure 2 A schematic diagram of a perspective view of a fan rotor is shown in Figure 4 Only the downstream longitudinal part of the aerodynamic surface is shown.

[0046] [ Figure 5 ] Figure 5 is a schematic diagram of a perspective view of the platform that forms the Figures 2 to 4 A portion of a fan rotor according to the invention is shown in FIG.

[0047] [ Figure 6 ] Figure 6 is a schematic diagram of a cross-sectional view of a second component of a downstream longitudinal portion of an aerodynamic surface of a platform forming part of a fan rotor according to an embodiment of the invention, the second component being connected by a flange to a toothed portion of a fan disk of the rotor.

[0048] It should be noted that the drawings are provided as examples and are not intended to limit the present invention. The drawings are schematic representations intended to facilitate understanding of the principles of the present invention and are not necessarily to scale for actual applications. In particular, the sizes of the various elements shown do not represent actual sizes. For example, Figures 2 to 4In FIG. 1 , only one fan blade is shown, the other blades having been removed to better observe the first member and the second member of the longitudinal portion of the aerodynamic surface. DETAILED DESCRIPTION

[0049] In the following, reference is made to all the drawings which are combined together. Where reference is made to one or more specific drawings, these drawings should be combined with the other drawings to identify the designated reference numerals.

[0050] Main reference Figures 2 to 6 , the present invention relates to a fan rotor 1 , advantageously intended for an aircraft turbine.

[0051] This rotor 1 is mounted to rotate about an axis of rotation and comprises a fan disk 2 and fan blades 3 comprising a root press-fitted in a socket located at the periphery of the disk 2, of which only one blade 3 is visible. Each blade 3 comprises a soffit, a dorsal, a leading edge 3a and a trailing edge 3b.

[0052] Advantageously, the periphery of the disk 2 is toothed by being arranged with teeth 16, advantageously of trapezoidal section and extending axially on the disk 2 relative to the axis of rotation of the rotor 1. At least one wedge 17 is arranged on the upstream side between two adjacent teeth 16 forming a socket for receiving the root of a blade 3, this wedge 17 being intended to block the blade root axially in its corresponding socket.

[0053] The platforms 4 are inserted between the fan blades 3 and fixed to the periphery of the disk 2. Thus, each platform 4 can be inserted between two consecutive fan blades 3.

[0054] Each platform 4 comprises an aerodynamic surface (at Figure 2 Referenced 4a), the aerodynamic surface extends substantially along said axis from the leading edge 3a of the two blades 3 to the trailing edge 3b of the two blades, the platform 4 being mounted between the two blades.

[0055] According to the invention, the aerodynamic surface 4 a comprises an upstream longitudinal portion 40 situated on the side of the leading edge 3 a of the blade 3 and a downstream longitudinal portion 41 situated on the side of the trailing edge 3 b of the blade 3 .

[0056] The upstream longitudinal portion 40 of the aerodynamic surface 4a is supported by a first member 5 of the platform 4, which is pivotably fixed to the fan disk 2. The downstream longitudinal portion 41 of the aerodynamic surface 4a is supported by a second member 6 of the platform 4. This second member 6 is independent of the first member 5 and is pivotably fixed to the fan disk 2.

[0057] The second member 6 enables the downstream longitudinal portion 41 to follow the displacement of the trailing edges 3b of the two associated fan blades 3. In operation, the downstream longitudinal portion 41 of the aerodynamic surface 4a can perform a rotational movement about its pivotal connection with the fan disk 2.

[0058] The main difficulty in implementing the invention is controlling the radial clearance between the upstream longitudinal portion 40 and the downstream longitudinal portion 41. This clearance must be neither too small to allow the two portions to rotate relative to each other nor too large to ensure that the two portions are centered relative to each other.

[0059] Furthermore, the rotation of the downstream longitudinal portion 41 relative to the upstream longitudinal portion 40 causes a potential energy jump to be generated in the passage of the aerodynamic surface 4 a.

[0060] Furthermore, it is important to implement a sealing technology which, on the one hand, is able to control the interface between the two longitudinal sections 40, 41 and, on the other hand, is able to compensate for the downstream casing (in Figure 1 The clearance required for the rotation of the downstream longitudinal portion 41 is marked as 15 in the figure. The seal can be an O-ring, a split seal or an Omega seal, etc.

[0061] Reference Figure 5 The platform 4 may further include a receiving portion on one of the longitudinal sides of the platform supporting the first member 5 and the second member 6 , and the receiving portion 18 may be arranged between the first member 5 and the second member 6 .

[0062] The downstream longitudinal portion 41 may have a free end 41a bent towards the fan disk 2 and abutting against a component that is not in contact with the fan disk 2. Figures 2 to 5 shown in Figure 1 The downstream housing 15 is shown as being fixed to the fan disc 2 by means of legs.

[0063] The aerodynamic surface 4a may be slightly concave on the side of the aerodynamic surface facing the two fan blades 3 building the aerodynamic surface and curved over the width of the aerodynamic surface.

[0064] Without limitation, the axial dimension of the upstream longitudinal portion 40 may be between 0.5 and 1.5 times the axial dimension of the downstream longitudinal portion 41. Thus, the axial dimension of the upstream longitudinal portion 40 may be less than, equal to, or greater than the axial dimension of the downstream longitudinal portion 41.

[0065] The first member 5 may be supported by the bent end 40a of the upstream longitudinal portion 40. The bent end 40a of the upstream longitudinal portion 40 may be fixed to the fan disk 2 by a fixing element, thereby forming the first member 5, preferably one of the teeth 16 being arranged on the circumference of the fan disk 2. Preferably, the bent end 40a of the upstream longitudinal portion is fixed to the longitudinal end of the tooth 16 by the edge of the tooth 16, which forms the thickness of the tooth.

[0066] The second member 6 can be fixed to the fan disk 2 by means of a single fixing element 7 which defines the pivot axis of the downstream longitudinal portion 41 relative to the disk 2 .

[0067] The width of the downstream longitudinal portion 41 can be increased by approaching the free end of the downstream longitudinal portion 41, which advantageously supports the curved edge. This depends on whether the distance between two consecutive fan blades 3 remains constant.

[0068] Still the main reference Figure 2 and Figure 6 , more specifically refer to Figure 6 The second member 6 associated with the downstream longitudinal portion 41 may comprise a fixing bracket 6 applied axially to the flange 8 of the fan disk 2 .

[0069] At the longitudinal end of the tooth 16 farthest from the first member 5, the flange 8 may extend from the tooth 16 at the periphery of the fan disk 2. The flange 8 may be supported by the face of the tooth 16 opposite to the inner face of the aerodynamic surface 4a supporting the first member 5 and the second member 6, advantageously the flange extending perpendicularly to the face of the tooth 16 supporting the flange.

[0070] The fixing bracket 6 may be elongated with the downstream longitudinal portion 41 extending away from the disc 2. The fixing bracket 6 may have a curved end portion 6b with a hole 6a passing therethrough.

[0071] The hole 6a of the fixing bracket 6 is an axial hole which is aligned with the axial hole 8a of the flange 8 in the fixing position of the second member 6. Then, the bent end portion 6b of the fixing bracket 6 rests on the flange 8 of the fan disk 2.

[0072] exist Figure 6 As can be seen particularly clearly in FIG. 8 , the fixing element 7 runs through the axial hole 6 a of the bent end portion 6 b of the fixing bracket 6 and through the axial hole 8 a of the flange 8 .

[0073] To enable free rotation of the curved end portion 6b of the fixing bracket 6 of the second member 6 relative to the fixing element 7, the hole 6a of the curved end portion 6b of the fixing bracket 6 may at least partially receive a ring 9 through which the fixing element 7 passes.

[0074] Thus, there may be an inner portion 9a of the ring 9, which is housed in the hole 6a of the curved end portion 6b of the fixing bracket 6, the inner portion 9a of the ring 9 being inserted between the inner wall of the hole 6a and the outer wall of the fixing element 7. The rest of the ring 9 is the outer portion 9b of the ring 9, which is arranged outside the curved end portion 6b and can form a collar 9b that can abut against an axial displacement of the curved end portion 6b of the fixing bracket 6.

[0075] The ring 9 can be clamped axially against the flange 8 of the disk 2, thereby ensuring a secure fixation, but is still separated from the curved end portion 6 b of the fixing bracket 6 by an axial gap Ja and a radial gap Jr. Therefore, due to the axial gap Ja and the radial gap Jr with the ring 9, the curved end portion 6 b of the fixing bracket 6 can pivot around the fixing element 7.

[0076] Therefore, the radial gap Jr can be limited by the part of the ring 9 inside the curved end part 6b, and the axial gap Ja can be limited by the part of the ring 9 outside the curved end part 6b. Advantageously, this part of the ring 9 outside the curved end part 6b is in the form of a ring part 9b, which abuts and prevents the flange 8 from being removed in the axial direction of the curved end part 6b of the fixed bracket 6.

[0077] Still the main reference Figure 6 The fixing element 7 may be a screw having a head 7a and a threaded shaft.

[0078] The head 7a of the screw can be supported on the face of the flange 8 opposite to the face facing the ring 9, or on the face of an insert 10 located on this face, the insert being located on the face of the flange 8 opposite to the face facing the ring 9, the latter alternative being as Figure 6 As shown, the insert 10 is, for example, a washer or, in this case, a component forming part of the low-pressure compressor drum of the turbomachine. It is also possible to use a nut instead of the head 7a.

[0079] At its other free end, the threaded rod can also receive a nut 11 which bears against the ring 9 and clamps it against the flange 8 via its inner portion 9 a at the bent end portion 6 b of the fixing bracket 6 .

[0080] More specifically refer to Figure 3 , Figure 3The upstream longitudinal portion 40 is shown without the downstream longitudinal portion 41, and one of the longitudinal portions 40, 41 (in Figure 3 The upstream longitudinal section 40 (not limiting) is located in the other longitudinal section 41 (in the longitudinal section 40, 41) Figure 3 A bearing surface 12 for the other longitudinal portion 41 may be included at the longitudinal end on the downstream longitudinal portion 41 side.

[0081] This makes it possible to avoid mismatching between the upstream longitudinal portion 40 and the downstream longitudinal portion 41 and enables the upstream longitudinal portion 40 to support the downstream longitudinal portion 41 at one end of the downstream longitudinal portion 41 which is spaced a distance from the second member 6 .

[0082] As used in the combination Figure 3 and Figure 4 As can be seen particularly clearly in FIG. 4 , the longitudinal portions 40 , 41 of the aerodynamic surface 4a can comprise circumferential edges facing each other. The bearing surface 12 can extend along one of these edges over only a portion of the circumferential extent of this edge.

[0083] The portion of the bearing surface 12 may be arranged symmetrically with respect to the peripheral edge bearing it, wherein only the end portion of the peripheral edge bearing it is not connected to the bearing surface 12. Alternatively, the bearing surface 12 may be supported by the main portion of the peripheral edge.

[0084] A particularly advantageous application of such a fan rotor 1 is in a turbomachine, advantageously in an aircraft turbomachine.

[0085] The invention is in no way limited to the embodiments described and shown which are given merely as examples.

Claims

1. A fan rotor (1) for a turbomachine, the fan rotor (1) having an axis of rotation and comprising: - fan tray (2), - fan blades (3), each comprising a root portion press-fitted into a socket at the periphery of the fan disk (2), each fan blade (3) comprising a soffit, a dorsal spur, a leading edge (3a) and a trailing edge (3b), - platforms (4) inserted between the fan blades (3) and fixed to the periphery of the fan disk (2), each platform (4) comprising an aerodynamic surface (4a) extending substantially along the axis from the leading edge (3a) of the fan blade (3) to the trailing edge (3b) of the fan blade, the platform (4) being mounted between the fan blades, Characterized in that the aerodynamic surface (4a) comprises an upstream longitudinal portion (40) and a downstream longitudinal portion (41), the upstream longitudinal portion being located on the side of the leading edge (3a) of the fan blade (3), the downstream longitudinal portion being independent of the upstream longitudinal portion, the downstream longitudinal portion being located on the side of the trailing edge (3b) of the fan blade (3), the upstream longitudinal portion (40) being supported by a first member (5) of the platform (4), the first member of the platform being fixed to the fan disk (2), and the downstream longitudinal portion (41) being supported by a second member of the platform (4), the second member of the platform being independent of the first member (5) and fixed to the fan disk (2), wherein one of the upstream longitudinal portion (40) and the downstream longitudinal portion (41) comprises, at its longitudinal end located on the side of the other of the upstream longitudinal portion (40) and the downstream longitudinal portion (41), a bearing surface (12) for the other longitudinal portion, wherein the upstream longitudinal portion (40) and the downstream longitudinal portion (41) comprise circumferential edges facing each other, the bearing surface (12) extending along one of these edges over only a portion of the circumferential extent of the edge and protruding from the edge, wherein the second member is pivotably fixed to the fan disk (2), wherein the second member is fixed to the fan disk (2) by means of a single fixing element (7) which defines the pivot axis of the downstream longitudinal portion (41) relative to the fan disk (2), And wherein the second member comprises a fixing bracket (6) which is axially applied to the flange (8) of the fan disk (2), the fixing bracket (6) being elongated and having a curved end portion (6b), the curved end portion having an axial hole (6a) aligned with the axial hole (8a) of the flange (8), the fixing element (7) passing through the axial hole (6a) of the fixing bracket (6) and the axial hole (8a) of the flange (8).

2. The fan rotor (1) according to claim 1, wherein: The axial dimension of the upstream longitudinal portion (40) along the axis of rotation of the fan rotor is between 0.5 and 1.5 times the axial dimension of the downstream longitudinal portion (41).

3. The fan rotor (1) according to claim 1, wherein: The bore of the fixing bracket (6) at least partially receives a ring (9) through which the fixing element (7) passes, the ring (9) being clamped and spaced from the fixing bracket (6) by an axial play (Ja) and a radial play (Jr).

4. The fan rotor (1) according to claim 3, wherein: The fixing element (7) is a screw whose head (7a) rests on the face of the flange (8) or on the face of an insert (10) located on this face and whose threaded stem receives a nut (11) resting on the ring (9).

5. Aircraft turbomachine, characterized in that it comprises a fan rotor (1) according to any one of claims 1 to 4.

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