Axial protection and retention device for a blade root

Abstract

Pattern (400) of a member for protecting and axially retaining a turbine blade root comprising: a substantially rectangular primary panel (410); a substantially rectangular secondary panel (420); a substantially rectangular first secondary flap (422) and second secondary flap (424); a substantially rectangular first secondary leg (426) and second secondary leg (428); a substantially rectangular tertiary panel (430), the pattern (400) further comprising: a substantially rectangular additional secondary panel (420'); a substantially rectangular first additional secondary flap (422') and second additional secondary flap (424'); a substantially rectangular first additional secondary leg (426') and second additional secondary leg (428'); an substantially rectangular additional tertiary panel (430'). Abstract Figure: Figure 4

Description

Title of the invention: Axial protection and retention device for a blade root Technical field

[0001] The present disclosure relates to the field of protection and axial retention members for a turbine blade root. Prior art

[0002] [Fig.l] represents a turbine of a turbomachine according to the prior art. The turbomachine comprises a longitudinal axis parallel to the axis X' shown.

[0003] The turbine 10 is arranged downstream of an annular combustion chamber 12 and comprises several wheels 14 arranged alternately with annular rows of fixed blades 16. The wheels 14 are driven in rotation by the flow of hot gases leaving the combustion chamber 12.

[0004] A wheel 14 comprises a disc 18 having on its external periphery a plurality of longitudinal dovetail or similar cells 20 in which blade roots 22 are axially engaged and radially retained by shape cooperation.

[0005] To this end, the blade roots 22 have a bulbous shape ensuring their radial retention in the cells 20 of the disc 18, which are delimited laterally (circumferentially) by disc teeth (or ribs) 23.

[0006] As illustrated in [Fig.2], a blade 24 thus comprises a root 22 connected externally to a platform 26 extending circumferentially, and a blade 28 receiving the flow of hot gases and extending radially from the platform 26.

[0007] The platforms 26 extend circumferentially end to end so as to form an annular wall internally delimiting the annular flow vein of the hot gases and preventing the reintroduction of hot gases at the level of the internal periphery of the disc 18.

[0008] Each blade root 22 comprises at its upstream and downstream ends a projecting portion 30 extending circumferentially and arranged immediately above a disc tooth 23 ([Fig.3]).

[0009] These projecting parts or walls 30 come to bear on the disc teeth 23, which makes it possible to limit the tilting in the circumferential direction of the blade roots 22 during operation.

[0010] These walls 30 also make it possible to limit the reintroduction of hot gases between the platforms 26 and the disc teeth 23, thus avoiding significant heating of the disc 18.

[0011] In operation, the blades are subjected to vibrations generating contact and friction forces between the blade roots 22 and the disc 18, in particular the disc teeth 23 and the cells 20 of the disc 18.

[0012] It is known from the prior art to use foils arranged at the contact interface between the blade roots and the disc teeth 23 in order to protect said contact interface from contact and friction forces which may damage the elements in contact.

[0013] It has been found that the foils are subjected to pinching stresses and relative displacements between the blade and the disc which can cause their deformation and / or their tearing which can lead to premature wear and a reduction in the service life of the blade and / or the disc.

[0014] In order to avoid this, it is necessary to further improve the axial retention device of the foils. Summary

[0015] To this end, the present document proposes a pattern of a protection and axial retention member for a turbine blade root comprising: - a substantially rectangular primary panel having a median of its length, called the circumferential median, and a median of its width, called the axial median; - a substantially rectangular secondary panel which comprises a first circumferential edge directly connected to a first length of the primary panel; - a first secondary flap and a second secondary flap which are substantially rectangular, the first secondary flap being directly connected to a first lateral edge of the secondary panel and is connected to the secondary panel by a first junction zone, the second secondary flap being directly connected to a second lateral edge of the secondary panel which is axially opposite the first lateral edge, the second secondary flap being connected to the secondary panel by a second junction zone; - a first secondary leg and a second secondary leg which are substantially rectangular, the first secondary leg being directly connected to a lateral edge of the first secondary flap and is connected to the first secondary flap by a third junction zone, the second secondary leg being directly connected to a lateral edge of the second secondary flap and is connected to the first secondary flap by a fourth junction zone, - a tertiary panel of substantially rectangular shape, the tertiary panel comprising a first circumferential edge directly connected to a second circumferential edge of the secondary panel opposite the first circumferential edge by a fifth junction zone, the pattern further comprising: - an additional substantially rectangular secondary panel which comprises a first additional circumferential edge directly connected to a second length of the primary panel; - a first additional secondary flap and a second additional secondary flap which are substantially rectangular, the first additional secondary flap being directly connected to a first additional lateral edge of the additional secondary panel and is connected to the additional secondary panel by a first additional joining zone, the second additional secondary flap being directly connected to a second additional lateral edge of the additional secondary panel which is axially opposite the first additional lateral edge, the second additional secondary flap being connected to the additional secondary panel by a second additional joining zone; - a first additional secondary leg and a second additional secondary leg substantially rectangular, the first additional secondary leg being directly connected to an additional lateral edge of the first additional secondary flap and is connected to the first additional secondary flap by a third additional joining zone, the second additional secondary leg being directly connected to an additional lateral edge of the second additional secondary flap and is connected to the first additional secondary flap by a fourth additional joining zone, - an additional tertiary panel of substantially rectangular shape, the additional tertiary panel comprising a first circumferential edge directly connected to a second additional circumferential edge of the additional secondary panel opposite the first additional circumferential edge by a fifth additional joining zone, wherein: - the sum of the axial dimension of the first circumferential edge, the axial dimension of the first secondary panel and the axial dimension of the second secondary panel is greater than or equal to the axial dimension of the tertiary panel; - the sum of the axial dimension of the first additional circumferential edge, the axial dimension of the first additional secondary panel and the axial dimension of the second additional secondary panel is greater than or equal to the axial dimension of the additional tertiary panel; - the circumferential dimension of the first secondary leg and / or the circumferential dimension of the second secondary leg is between 80% and 100% of the circumferential dimension of the tertiary panel; - the circumferential dimension of the first additional secondary leg and / or the circumferential dimension of the second additional secondary leg is between 80% and 100% of the circumferential dimension of the additional tertiary panel.

[0016] The terms axial, radial and circumferential are defined relative to the longitudinal axis of the turbomachine.

[0017] The terms upstream and downstream are defined in relation to the direction of gas flow.

[0018] By pattern of an organ, we mean the pattern of said organ, i.e. the flat geometric figure in a single piece which allows said organ to be reconstituted after several folds and / or conformations.

[0019] The secondary panel, the first secondary flap, the second secondary flap, the first secondary leg, the second secondary leg and the tertiary panel may form a symmetrical intrados assembly with respect to the circumferential median.

[0020] The additional secondary panel, the first additional secondary flap, the second additional secondary flap, the first additional secondary tab, the second additional secondary tab and the additional tertiary panel may form an extrados assembly symmetrical with respect to a circumferential axis parallel to the circumferential median, said circumferential axis being separated by an axial distance from the circumferential median.

[0021] The corners at the ends of the first circumferential edge of the tertiary panel may be rounded so that said corners each comprise an arc of a circle of between 10.5mm and 12.5mm.

[0022] The corners at the ends of the first additional circumferential edge of the additional tertiary panel may be rounded so that said corners each comprise an additional circular arc of between 10.5mm and 12.5mm.

[0023] The pattern may further comprise a first primary flap and a second primary flap that are substantially rectangular, the first primary flap being directly connected to a first length of the primary panel and is connected to the primary panel by an upstream primary junction area, the second primary flap being directly connected to a second length of the primary panel and is connected to the primary panel by a downstream primary junction area.

[0024] The axial dimension of the first circumferential edge may be less than or equal to the first length of the primary panel.

[0025] The axial dimension of the first additional circumferential edge may be less than or equal to the second length of the primary panel.

[0026] This document may also relate to a method of manufacturing an axial protection and retention member by conformation comprising the successive steps consisting of: a. obtain a metal sheet; b. cutting said metal sheet according to the pattern according to the aforementioned type; c. stamp and shape the primary panel so that said panel primary cooperates in shape with the blade root; d. conforming the tertiary panel along the fifth junction zone and the additional tertiary panel along the fifth additional junction zone so that the fifth junction zone and fifth additional junction zone are circumferentially curved towards the axial median; e. conforming the first secondary panel following the first joining area, the second secondary panel following the second joining area, the first additional secondary panel following the first additional joining area, the second additional secondary panel following the second additional joining area, so that the first joining area and the second joining area are curved towards the tertiary panel and the first additional joining area and the second additional joining area are curved towards the additional tertiary panel; f. shaping the first secondary leg along the third joining area, the second secondary leg along the fourth joining area, the first additional secondary leg along the third additional joining area, the second additional secondary leg along the fourth additional joining area, so that the third joining area and the fourth joining area are curved towards the tertiary panel and the third additional joining area and the fourth additional joining area are curved towards the additional tertiary panel, the first secondary leg, the second secondary leg and the tertiary panel cooperating together,

[0027] the first additional secondary leg, the second additional secondary leg and the additional tertiary panel cooperating together,

[0028] the first secondary flap, the second secondary flap, the first secondary leg, the second secondary leg and the tertiary panel delimiting a blocking volume, and

[0029] the first additional secondary flap, the second additional secondary flap, the first additional secondary leg, the second additional secondary leg and the additional tertiary panel delimiting an additional blocking volume.

[0030] By circumferentially towards the axial median, we mean in a circumferential (or lateral) direction opposite the axial median.

[0031] The metal sheet may comprise a thickness in a direction orthogonal to the circumferential median and the axial median, called the radial direction, of between 0.08 mm and 0.2 mm.

[0032] After conformation of the axial protection and retention member and installation with a corresponding blade root: - the secondary panel and the additional secondary panel are arranged circumferentially opposite the lateral stilts of the foot and match the shape of said stilts; - the first and second secondary shutters and the first and second additional secondary shutters are arranged axially opposite upstream and downstream walls which are connected to the lateral stilts, and match the shape of said upstream and downstream walls; the first and second secondary legs and the first and second additional secondary legs surround (wrap) the tertiary panel and the additional tertiary panel respectively. In particular, carrying out steps (e) and (f) after step (d) makes it possible to obtain such a configuration.

[0033] The first secondary leg, the second secondary leg and the tertiary panel may cooperate together such that the first secondary leg and the second secondary leg bear circumferentially on the tertiary panel.

[0034] In other words, inner faces of the first secondary leg and the second secondary leg may be in circumferential contact with an outer face of the tertiary panel.

[0035] The first additional secondary leg, the second additional secondary leg and the additional tertiary panel may cooperate together such that the first additional secondary leg and the second additional secondary leg bear circumferentially on the additional tertiary panel.

[0036] In other words, inner faces of the first additional secondary leg and the second additional secondary leg may be in circumferential contact with an outer face of the additional tertiary panel.

[0037] The blocking volume and the additional blocking volume thus formed make it possible to ensure the axial retention of the organ, and therefore to avoid any possible deformation, tearing or separation of the organ from the foot that it protects. Indeed, the blocking volume is retained between the lateral stilts and the upstream and downstream walls, resulting in the axial retention of the organ.

[0038] Furthermore, the cooperation of the elements delimiting the blocking volume and the additional blocking volume makes it possible to stiffen and improve the robustness of the blocking volume and the additional blocking volume, in a manner similar to a folded cardboard box.

[0039] The characteristics of the pattern of the axial protection and retention member now appear clearer.

[0040] The feature that the sum of the axial dimension of the first circumferential edge, the axial dimension of the first secondary flap and the axial dimension of the second secondary flap is greater than or equal to the axial dimension of the tertiary panel ensures that the first and second secondary legs surround the tertiary panel.

[0041] The feature that the sum of the axial dimension of the first additional circumferential edge, the axial dimension of the first additional secondary flap and the axial dimension of the second additional secondary flap is greater than or equal to the axial dimension of the additional tertiary panel ensures that the first and second additional secondary legs surround the additional tertiary panel;

[0042] The feature that the circumferential dimension of the first secondary leg and / or the circumferential dimension of the second secondary leg is between 80% and 100% of the circumferential dimension of the tertiary panel ensures that the ends of the tertiary panel are surrounded by the first secondary leg and / or the second secondary leg.

[0043] The feature that the circumferential dimension of the first additional secondary leg and / or the circumferential dimension of the second additional secondary leg is between 80% and 100% of the circumferential dimension of the additional tertiary panel ensures that the ends of the additional tertiary panel are surrounded by the first additional secondary leg and / or the second additional secondary leg.

[0044] In this way, any contact of the ends and edges of the tertiary panel and the additional tertiary panel with the upstream and downstream walls or the side stilts of the blade root, the ends and edges of the tertiary panel and the additional tertiary panel which may damage the upstream and downstream walls or the side stilts of the blade root.

[0045] The characteristic according to which the axial dimension of the first circumferential edge can be less than or equal to the first length of the primary panel makes it possible to take into account the axial dimension of the corresponding upstream and downstream walls.

[0046] The characteristic according to which the axial dimension of the first additional circumferential edge can be less than or equal to the second length of the primary panel makes it possible to take into account the axial dimension of the corresponding upstream and downstream walls.

[0047] The characteristic according to which the corners at the ends of the first circumferential edge of the tertiary panel are rounded so that said corners each comprise an arc of a circle of between 10.5 mm and 12.5 mm makes it possible to ensure that the tertiary panel does not have lateral edges which could damage the corresponding upstream and downstream walls.

[0048] The characteristic according to which the corners at the ends of the first additional circumferential edge of the additional tertiary panel are rounded so that said corners each comprise an additional arc of a circle of between 10.5 mm and 12.5 mm makes it possible to ensure that the additional tertiary panel does not have lateral (i.e. axial) edges which could damage the corresponding upstream and downstream walls.

[0049] The characteristic according to which the first secondary flap, the second secondary flap, the first secondary tab, the second secondary tab and the tertiary panel form a symmetrical intrados assembly with respect to the circumferential median allows the intrados assembly to be arranged on the intrados side of the blade, that is to say at the level of the lateral Péchasse and the upstream downstream walls which are on the intrados side of the blade.

[0050] The characteristic according to which the first additional secondary flap, the second additional secondary flap, the first additional secondary tab, the second additional secondary tab and the additional tertiary panel form an extrados assembly symmetrical with respect to a circumferential axis parallel to the circumferential median, said circumferential axis being separated by an axial distance from the circumferential median, allows the extrados assembly to be arranged on the extrados side of the blade, that is to say at the level of the lateral Péchasse and the upstream downstream walls which are on the extrados side of the blade.

[0051] Optionally, the secondary flaps and the additional secondary flaps of the pattern before conformation may have axial dimensions such that, after shaping, the secondary legs and the additional secondary legs are in contact with additional secondary legs and secondary legs of adjacent axial protection and retention members (i.e. circumferentially facing axial protection and retention members).

[0052] In this way, the secondary legs and the additional secondary legs of the axial protection and retention member and the adjacent axial protection and retention members cushion each other. Considered over the entire circumference, the axial protection and retention members of a turbine wheel can cushion each other.

[0053] The method may further comprise the additional step of shaping the first primary flap along the upstream primary junction area and the second primary flap along the downstream primary junction area, such that the upstream primary junction area and the downstream primary junction area are curved towards the circumferential median.

[0054] The additional step can be carried out after step (b) of the method of the aforementioned type, and at any time.

[0055] For example, the additional step may be performed between steps (c) and (d) or after step (f).

[0056] This document may also relate to a turbine wheel of a turbomachine with a longitudinal axis comprising: - a disc (18) comprising at its external periphery disc teeth delimiting longitudinal cells;

[0057] - a plurality of blades carried by the disc, each blade having an engaged root axially and retained radially in a longitudinal cell of the disc, said foot being connected to a platform by a lateral stilt which is connected at its upstream and downstream ends to upstream and downstream walls respectively;

[0058] - a plurality of protection members, each protection and retention member axial comprising:

[0059] — a primary part mounted and retained by shape cooperation in a cell longitudinal radially between the foot and said longitudinal cell, said primary part being capable of protecting the sides of the longitudinal cell and the foot;

[0060] — at least one first secondary part connected to a first end circumferential of the first part and mounted and retained by shape cooperation in a first lateral stilt of the foot and the corresponding upstream and downstream walls so that said at least one second part delimits a first axial retention volume.

[0061] The axial protection and retention member may be a foil. By foil is meant a sheet metal that is foldable and can be shaped.

[0062] The characteristics relating to the axial protection and retention member obtained according to the method of the aforementioned type can be integrated into at least one axial protection and retention member of said wheel, and for example into each axial retention protection member of said wheel.

[0063] In other words, the pattern of the axial protection and retention member may correspond to each axial protection and retention member of said wheel before application of steps (c) to (f) of the manufacturing method of the aforementioned type.

[0064] In other words, each axial protection and retention member of said wheel can correspond to the pattern of the axial protection and retention member after application of steps (c) to (f) of the manufacturing method of the aforementioned type.

[0065] In particular: - the primary panel of the pattern may correspond to the primary part of each axial protection and retention member of said wheel, - the secondary panel, the first and second secondary flaps, the first and second secondary legs, and the tertiary panel of the pattern may correspond to said at least one first secondary part of each axial protection and retention member of said wheel, - the additional secondary panel, the first and second additional secondary flaps, the first and second additional secondary legs, and the additional tertiary panel of the pattern may correspond to said at least one first secondary part of each axial protection and retention member of said wheel.

[0066] The blocking volume of the protection and axial retention member may correspond to the first axial retention volume of the foot.

[0067] Each axial protection and retention member may further comprise a second secondary part connected to a second circumferential end opposite the first circumferential end of the first part, and mounted and retained by shape cooperation in a second lateral brace of the foot and the corresponding upstream and downstream walls so that the second secondary part delimits a second axial retention volume of the foot.

[0068] The additional blocking volume of the protection and axial retention member may correspond to the second axial retention volume of the foot.

[0069] The secondary panel, the first and second secondary flaps, the first and second secondary tabs, and the tertiary panel of the pattern may correspond to a first secondary portion of each member of the axial protection and retention member of said wheel.

[0070] The additional secondary panel, the first and second additional secondary flaps, the first and second additional secondary tabs, and the additional tertiary panel of the pattern may correspond to a second secondary part of each axial protection and retention member of said wheel.

[0071] In other words, each axial protection and retention member may comprise a first secondary part and a second secondary part.

[0072] More particularly, the first secondary part of the pattern may correspond to the intrados assembly and the second secondary part of the pattern may correspond to the extrados assembly.

[0073] This document may also relate to a turbine, such as a low-pressure turbine, for an aircraft turbomachine with a longitudinal axis comprising a wheel of the aforementioned type.

[0074] This document may also relate to a longitudinal axis turbomachine, such as an aircraft turbojet or turboprop, comprising a turbine of the aforementioned type.

[0075] This document may also relate to an aircraft comprising at least one turbomachine of the aforementioned type.

[0076] Said aircraft may be an airplane or a rotary wing aircraft.

[0077] The features set forth in this document may, optionally, be implemented independently of one another or in combination with one another. Brief description of the drawings

[0078] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:

[0079] [Fig. 1] is a partial schematic half-view in section of a turbomachine turbine according to the prior art;

[0080] [Fig.2] is a schematic view from upstream of the connection between the blade roots and the disc of a wheel of the turbine of [Fig. 1];

[0081] [Fig.3] is a side diagram of a blade root of [Fig.2];

[0082] [Fig.4] is a flat view of a foot protection and axial retention member turbine blade according to an embodiment of the present document;

[0083] [Fig.5] is a detailed view illustrating the intrados side of the axial protection and retention member of [Fig.4];

[0084] [Fig.6] is a detailed view illustrating the extrados side of the axial protection and retention member of [Fig.4];

[0085] [Fig.7] is a perspective view of the axial protection and retention member of [Fig.4];

[0086] [Fig.8] is a side view of the axial protection and retention member of [Fig.4] surrounding a blade root;

[0087] [Fig.9] is an isolated perspective view and following an orthogonal section plane in the longitudinal direction of a turbine wheel comprising three blades arranged circumferentially end to end and three corresponding axial protection and retention members. Description of the embodiments

[0088] [Fig.4] is a flat view of a protection and axial retention member for a turbine blade root according to an embodiment of the present document.

[0089] In other words, [Fig.4] illustrates the pattern of the axial protection and retention member, before conformation.

[0090] The pattern 400 comprises a substantially rectangular primary panel 410 having a median Y of its length 410a, called the circumferential median Y, and a median X of its width 410b, called the axial median X.

[0091] It is understood that the axial median X is parallel to the longitudinal axis of the turbomachine.

[0092] In the remainder of this section, the terms upstream (AM) and downstream (AV), and intrados (IN) and extrados (EX) are defined in relation to the circumferential median Y and the axial median X respectively.

[0093] The primary panel 410 further comprises an upstream primary flap 412 (or first primary flap 412) and a downstream primary flap 414 (or second primary flap 414) which are substantially rectangular.

[0094] The upstream primary flap 412 comprises a length 412a-l directly connected to an upstream length 410b-l of the primary panel 410.

[0095] The upstream primary flap 412 is connected to the primary panel 410 by an upstream primary junction zone 411. This upstream primary junction zone 411 extends over the entire length 412a-l and part of the width 412b-l of the upstream primary flap 412.

[0096] Similarly, the downstream primary flap 414 comprises a length 414a-l directly connected to a downstream length 410b-2 of the primary panel 410.

[0097] The downstream primary flap 414 is connected to the primary panel 410 by a downstream primary junction zone 413. This downstream primary junction zone 413 extends over the entire length 414a-1 and part of the width 414b-1 of the downstream primary flap 414.

[0098] On the intrados side, the pattern 400 comprises a substantially rectangular secondary panel 420 which comprises a first length 420a-1 (or first circumferential edge 420a-l) directly connected to an intrados length 410a-l (or first length 410a-l) of the primary panel 410.

[0099] As illustrated in more detail in [Fig.5], the axial dimension L1 of the first length 420a-l is less than the intrados length 410a-l of the primary panel 410.

[0100] The pattern 400 further comprises an upstream secondary flap 422 (or first secondary flap 422) and a downstream secondary flap 424 (or second secondary flap 424) which are substantially rectangular.

[0101] The upstream secondary flap 422 comprises a downstream length 422b-1 directly connected to an upstream width 420b-1 (or first lateral edge 420b-1) of the secondary panel 420 and is connected to the secondary panel 420 by a first upstream secondary junction zone 421 (or first junction zone 421).

[0102] This first upstream secondary junction zone 421 extends over the entire downstream length 422b-1 and part of the width 422a-1 of the upstream secondary flap 422.

[0103] The width 422a-l of the upstream secondary flap 422 is of dimension L2-1.

[0104] Similarly, the downstream secondary flap 424 comprises an upstream length 424b-1 directly connected to a downstream width 420b-2 (or second lateral edge 420b-2) of the secondary panel 420 and is connected to the secondary panel 420 by a first downstream secondary junction zone 423 (or second junction zone 423).

[0105] This first downstream secondary junction zone 423 extends over the entire upstream length 424b-1 and part of the width 424a-1 of the downstream secondary flap 424.

[0106] The width 424a-1 of the downstream secondary flap 424 is of dimension L2-2.

[0107] The pattern 400 further comprises an upstream secondary leg 426 (or first leg secondary 426) and a downstream secondary leg 428 (or second secondary leg 428) substantially rectangular.

[0108] The upstream secondary tab 426 comprises a downstream length 426b-1 directly connected to an upstream length 422b-2 (or lateral edge 422b-2) of the upstream secondary flap 422 and is connected to the upstream secondary flap 422 by a second upstream secondary junction zone 425 (or third junction zone 425).

[0109] This second upstream secondary junction zone 425 extends over the entire downstream length 426b-1 and over a portion of the width 426a-1 of the upstream secondary tab 426.

[0110] The upstream length 426b-1 of the upstream secondary leg 426 is of dimension Hl-1 and equal to the dimension of the length 422b-1 of the upstream secondary flap 422.

[0111] Similarly, the downstream secondary tab 428 comprises an upstream length 428b-1 directly connected to a downstream length 424b-2 (or lateral edge 424b-2) of the upstream secondary flap 422 and is connected to the upstream secondary flap 422 by a second downstream secondary junction zone 427 (or fourth junction zone 427).

[0112] This second downstream secondary junction zone 427 extends over the entire upstream length 428b-1 and over a portion of the width 428a-1 of the downstream secondary tab 428.

[0113] The downstream length 428b-1 of the downstream secondary tab 428 is of dimension H1-2 and equal to the dimension of a length 424b-1 of the downstream secondary flap 424.

[0114] A tertiary panel 430 of substantially rectangular shape comprises a length 430a-1 directly connected to a second length 420a-2 (or second additional circumferential edge 420a-2) circumferentially opposite the first length 420a-1 of the secondary panel 420.

[0115] As illustrated in more detail in [Fig.5], the length 430a-1 comprises at its ends rounded corners 430a-2, 430a-3 which each comprise an arc of a circle C.

[0116] The tertiary panel 430 is connected to the secondary panel 420 by a tertiary junction zone 429 (or fifth junction zone 429).

[0117] This tertiary junction zone 429 extends over an entire end length 430a-4 (of dimension L3) and over a portion of a width 430b-1 of the tertiary panel 430.

[0118] The distance between length 430a-1 and end length 430a-4 is equal to H2.

[0119] In the illustrated embodiment, the upstream 422 and downstream 424 secondary flaps, the upstream 426 and downstream 428 secondary legs and the tertiary panel 430 are symmetrical with respect to the circumferential median Y, forming an intrados assembly.

[0120] In this way, we have H1-2 equal to Hl-1 and L2-2 equal to L2-1.

[0121] As illustrated in more detail in [Fig.5], the sum of L1, L2-1 and L2-2 is greater than or equal to L3, and Hl-1 (or Hl-2) is approximately equal to 80% of H2.

[0122] Similarly on the extrados side, the pattern 400 comprises an additional substantially rectangular secondary panel 420' which comprises a first length 420a-1' (or first additional circumferential edge 420a-1') directly connected to an extrados length 410a-2 (or second length 410a-2) of the primary panel 410.

[0123] As illustrated in more detail in [Fig.6], the axial dimension Ll' of the first length 420a-l' is less than the extrados length 410a-2 of the primary panel 410.

[0124] The pattern 400 further comprises an additional upstream secondary flap 422' (or first additional secondary flap 422') and an additional downstream secondary flap 424' (or second additional secondary flap 424') which are substantially rectangular.

[0125] The additional upstream secondary flap 422' comprises a downstream length 422b-1' directly connected to an upstream width 420b-1' (or first additional lateral edge 420b-1') of the additional secondary panel 420' and is connected to the additional secondary panel 420' by a first additional upstream secondary junction zone 421' (or first additional junction zone 421').

[0126] This first additional upstream secondary junction zone 421' extends over the entire downstream length 422b-1' and part of the width 422a-1' of the additional upstream secondary flap 422'.

[0127] The width 422a-1' of the additional upstream secondary flap 422' is of dimension L2-r.

[0128] Similarly, the additional downstream secondary flap 424' comprises an upstream length 424b-1' directly connected to a downstream width 420b-2' (or second additional lateral edge 420b-2') of the additional secondary panel 420' and is connected to the additional secondary panel 420' by a first additional downstream secondary junction zone 423' (or second additional junction zone 423').

[0129] This first additional downstream secondary junction zone 423' extends over the entire downstream length 424b-1' and part of the width 424a-1' of the additional downstream secondary flap 424'.

[0130] The width 424a-1' of the additional downstream secondary flap 424' is of dimension L2-2'.

[0131] The pattern 400 further comprises an additional upstream secondary leg 426' (or first additional secondary leg 426') and an additional downstream secondary leg 428' (or second additional secondary leg 428') which are substantially rectangular.

[0132] The additional upstream secondary tab 426' comprises a downstream length 426b-1' directly connected to an upstream length 422b-2' (additional lateral edge 422b-2') of the additional upstream secondary flap 422' and is connected to the additional upstream secondary flap 422' by a second additional upstream secondary junction zone 425' (or third additional junction zone 425').

[0133] This second additional upstream secondary junction zone 425' extends over the entire downstream length 426b-1' and over a portion of the width 426a-1' of the additional upstream secondary leg 426'.

[0134] The upstream length 426b-1' of the additional upstream secondary tab 426' is of dimension Hl-1' and equal to the dimension of a length 422b-1' of the additional upstream secondary flap 422'.

[0135] Similarly, the additional downstream secondary tab 428' comprises an upstream length 428b-1' directly connected to a downstream length 424b-2' (or additional lateral edge 424b-2') of the additional upstream secondary flap 422' and is connected to the additional downstream secondary flap 422' by a second additional downstream secondary junction zone 427' (or fourth additional junction zone 427').

[0136] This second additional downstream secondary junction zone 427' extends over the entire downstream length 428b-1' and over a portion of the width 428a-1' of the additional downstream secondary tab 428'.

[0137] The downstream length 428b-1' of the additional downstream secondary tab 428' is of dimension H1-2' and equal to the dimension of a length 424b-1' of the additional downstream secondary flap 424'.

[0138] An additional tertiary panel 430' of substantially rectangular shape comprises a length 430a-1' directly connected to a second length 420a-2' (or second additional circumferential edge 420a-2') circumferentially opposite the first length 420a-1' of the additional secondary panel 420'.

[0139] As illustrated in more detail in [Fig.6], the length 430a-1' comprises at its ends rounded corners 430a-2', 430a-3' which each comprise an additional circular arc C'.

[0140] The additional tertiary panel 430' is connected to the additional secondary panel 420' by an additional tertiary junction zone 429' (or fifth additional junction zone 429').

[0141] This additional tertiary junction zone 429' extends over an entire end length 430a-4' (of dimension L3') and over a portion of a width 430b-1' of the additional tertiary panel 430'.

[0142] The distance between length 430a-1' and end length 430a-4' is equal to H2'.

[0143] In the illustrated embodiment, the additional upstream 422' and downstream 424' secondary flaps, the additional upstream 426' and downstream 428' secondary tabs and the additional tertiary panel 430' are symmetrical with respect to a circumferential axis Y' parallel to the circumferential median Y, forming an extrados assembly.

[0144] The circumferential axis Y' is separated by an axial distance d from the circumferential median Y.

[0145] In this way, we have Hl-2' equal to Hl-1' and L2-2' equal to L2-1'.

[0146] As illustrated in more detail in [Fig.6], the sum of Ll', L2-1' and L2-2' is greater than or equal to L3', and Hl-1' (or Hl-2') is approximately equal to 80% of H2'.

[0147] Reference is now made to [Fig.7] which illustrates a perspective view of the pattern 400 after conformation, namely an axial protection and retention member 401. A radial axis Z is defined orthogonal to the circumferential median Y and the axial median X.

[0148] The tertiary panel 430 has been stamped and shaped so as to be able to fit the bottom of the bulb-shaped blade root and fit the lateral portions of said blade root.

[0149] The upstream primary flap 412 and the downstream primary flap 414 were shaped according to the upstream primary junction zone 411 and the downstream primary junction zone 413. respectively. The upstream primary flap 412 and the downstream primary flap 414 are oriented radially outward.

[0150] Thus, the upstream primary flap 412 and the downstream primary flap 414 are intended to allow axial retention of the blade root housed axially between them.

[0151] The secondary panels 420, 420' directly connected to the radially outer ends (i.e. the lengths 410a-l, 410a-2 of the primary panel 410 when flat) extend radially outward.

[0152] The tertiary panels 430, 430' have been shaped according to the tertiary junction zones 429, 429' so that the tertiary junction zones 429, 429' are curved circumferentially towards the axial median X.

[0153] In other words, the tertiary junction zone 429 is curved in the intrados direction and the additional tertiary junction zone 429' is curved in the extrados direction. In other words, the junction zone 429 and the additional junction zone 429' are curved so as to open onto the outside of the axial protection and retention member 401.

[0154] The secondary flaps 424, 426, 424', 426' have been shaped according to the first secondary junction zones 421, 421' so that the first secondary junction zones 421, 421' are curved towards the corresponding shaped tertiary panel 430, 430' and so as to match the shape of the upstream 30a and downstream 30b walls of the blade root.

[0155] The secondary tabs 426, 428, 426', 428' have been shaped according to the second secondary joining zones 421, 421' 423, 423' so that the second secondary joining zones 421, 421' 423, 423' are curved towards the corresponding shaped tertiary panel 430, 430'.

[0156] In this manner, the end widths and lengths of the corresponding shaped tertiary panel 430, 430' are surrounded (wrapped) by the secondary flaps 424, 426, 424', 426'.

[0157] Intrados 700 and extrados 700' blocking volumes (or blocking volume 700 and additional blocking volume 700') are thus delimited by the secondary tabs 426, 428, 426', 428' the secondary flaps 424, 426, 424', 426' and the tertiary panels 430, 430'.

[0158] When the axial protection and retention member 401 cooperates in shape with the blade root as illustrated in [Fig.8], these blocking volumes 700, 700' make it possible to improve the axial retention of the axial protection and retention member 401.

[0159] Indeed, the upstream face 422c of the upstream secondary flap 422 is axially opposite the upstream wall 30a and the downstream face 424c of the downstream secondary flap 424 is axially opposite the downstream wall 30b.

[0160] The upstream secondary flap 422 thus forms a structural element making it possible to prevent contact between the tertiary panel 430 (in particular its upstream lateral edges) and the upstream wall 30a.

[0161] The downstream secondary flap 424 thus forms a structural element making it possible to prevent contact between the tertiary panel 430 (in particular its downstream lateral edges) and the downstream wall 30b.

[0162] Furthermore, an internal face 420c of the secondary panel 420 is circumferentially opposite the lateral flange 31 of the blade root 22.

[0163] In operation, the blocking volumes 700, 700' are rigid and robust in the face of pinching constraints and relative movements between the blade root 22 and the disc 18.

[0164] As illustrated in Figures 7 to 8, the wheel 14 of the turbine 10 of the longitudinal axis turbomachine comprises: - a disc 18 comprising at its external periphery disc teeth 23 delimiting longitudinal cells 20;

[0165] - a plurality of blades carried by the disc 18, each blade comprising a root 22 axially engaged and radially retained in a longitudinal cell 20 of the disc 1), said foot 22 being connected to a platform by a lateral stilt 31 which is connected at its upstream and downstream ends to upstream walls 30a and downstream 30b respectively;

[0166] - a plurality of protection members 401, each protection member and axial retention 401 comprising:

[0167] — a primary part PI mounted and retained by shape cooperation in a longitudinal cell radially between the foot 22 and said longitudinal cell 20, said primary part PI being capable of protecting the sides of the longitudinal cell 20 and the foot 22;

[0168] — at least one first secondary part P2 connected to a first end circumferential of the first part PI and mounted and retained by shape cooperation in a first lateral flange 31 of the foot 22 and the corresponding upstream and downstream walls so that said at least one second part P2 delimits a first axial retention volume.

[0169] Furthermore, each axial protection and retention member 401 may further comprise a second secondary part P2' connected to a second circumferential end opposite the first circumferential end of the first part, and mounted and retained by shape cooperation in a second lateral flange of the foot and the corresponding upstream and downstream walls so that the second secondary part P2' delimits a second axial retention volume of the foot.

[0170] The axial protection and retention member 401 shown in Figures 7 to 8 may be the pattern 400 illustrated in Figures 4 to 6.

[0171] In this case, we therefore understand that:

[0172] - the primary panel 410 of the pattern 400 may correspond to the primary part PI of each axial protection and retention member 401 of said wheel 14,

[0173] - the secondary panel 420, the first and second secondary flaps 422, 424, the first and second secondary legs 426, 428, and the tertiary panel 430 of the pattern 400 may correspond to the first secondary part P2 of each axial protection and retention member 401 of said wheel 14,

[0174] - the additional secondary panel 420', the first and second flaps additional secondary legs 422, 424', the first and second additional secondary legs 426', 428', and the additional tertiary panel 430' of the pattern 400 may correspond to the second secondary part P2' of each axial protection and retention member 401 of said wheel 14.

[0175] [Fig.9] illustrates a turbine wheel 14 and the arrangement thereon end to end circumferentially of three blade feet 22 which are housed in respective longitudinal cells 20 and each enveloped by an axial protection and retention member 401.

[0176] The circumferential cooperation and arrangement of several protection members 401 are thus represented.

[0177] An intrados assembly of an axial protection and retention member 401 is thus circumferentially opposite an extrados assembly of an adjacent axial protection and retention member.

[0178] More particularly, the external faces of the secondary tabs 426, 428, 426', 428' (not illustrated or partially illustrated in the sectional view of [Fig.9]) of the adjacent protection members 401 are circumferentially opposite each other.

[0179] The secondary legs 426, 428, 426', 428' form a structural element making it possible to prevent contact between the tertiary panels 430, 430' facing each other circumferentially.

[0180] In an embodiment not illustrated, the external faces of the secondary legs 426, 428, 426', 428' of the adjacent protection members 401 are in contact so as to allow damping in operation.

Claims

Claims

1. Wheel (14) of a turbine (10) of a turbomachine with a longitudinal axis comprising: - a disc (18) comprising at its external periphery disc teeth (23) delimiting longitudinal cells (20); - a plurality of blades carried by the disc (18), each blade comprising a root (22) axially engaged and radially retained in a longitudinal cell (20) of the disc (18), said root (22) being connected to a platform by a lateral stilt (31) which is connected at its upstream and downstream ends to upstream (30a) and downstream (30b) walls respectively; - a plurality of protection members (401), each protection and axial retention member (401) comprising: — a primary part (PI) mounted and retained by shape cooperation in a longitudinal cell radially between the foot (22) and said longitudinal cell (20), said primary part (PI) being capable of protecting the sides of the longitudinal cell (20) and the foot (22);— at least one first secondary part (P2) connected to a first circumferential end of the first part (PI) and mounted and retained by shape cooperation in a first lateral brace (31) of the foot (22) and the corresponding upstream and downstream walls so that said at least one second part (P2) delimits a first axial retention volume.;

2. Wheel (14) according to the preceding claim, in which each axial protection and retention member (401) further comprises a second secondary part (P2') connected to a second circumferential end opposite the first circumferential end of the first part (PI), and mounted and retained by shape cooperation in a second lateral flange of the foot and the corresponding upstream and downstream walls so that the second secondary part delimits a second axial retention volume of the foot.

3. Pattern (400) intended to be shaped into a protective and axial retention member (401) for a turbine blade root of a turbine wheel (14) (10) according to any one of the preceding claims, said pattern (400) comprising: - a substantially rectangular primary panel (410) having a median (Y) of its length (410a), called circumferential median (Y), and a median (X) of its width (410b), called axial median (X); - a substantially rectangular secondary panel (420) which comprises a first circumferential edge (420a-1) directly connected to a first length (410a-1) of the primary panel (410); - a first secondary flap (422) and a second secondary flap (424) substantially rectangular, the first secondary flap (422) being directly connected to a first lateral edge (420b-1) of the secondary panel (420) and is connected to the secondary panel (420) by a first junction zone (421), the second secondary flap (424) being directly connected to a second lateral edge (420b-2) of the secondary panel (420) which is axially opposite the first lateral edge (420b-1), the second secondary flap (424) being connected to the secondary panel (420) by a second junction zone (423); - a first secondary leg (426) and a second secondary leg (428) which are substantially rectangular, the first secondary leg (426) being directly connected to a lateral edge (422b-2) of the first secondary flap (422) and is connected to the first secondary flap (422) by a third junction zone (425), the second secondary leg (428) being directly connected to a lateral edge (424b-2) of the second secondary flap (424) and is connected to the first secondary flap (422) by a fourth junction zone (427); and - a tertiary panel (430) of substantially rectangular shape, the tertiary panel (430) comprising a first circumferential edge (430a-1) directly connected to a second circumferential edge (420a-2) of the secondary panel (420) opposite the first circumferential edge (420a-1) by a fifth junction zone (429), the pattern (400) further comprising: - an additional secondary panel (420') substantially rectangular which comprises a first edge additional circumferential (420a-1') directly connected to a second length (410a-2) of the primary panel (410); a first additional secondary flap (422') and a second additional secondary flap (424') substantially rectangular, the first additional secondary flap (422') being directly connected to a first additional lateral edge (420b-1') of the additional secondary panel (420') and is connected to the additional secondary panel (420') by a first additional joining zone (421'), the second additional secondary flap (424') being directly connected to a second additional lateral edge (420b-2') of the additional secondary panel (420') which is axially opposite the first additional lateral edge (420b-1'), the second additional secondary flap (424') being connected to the additional secondary panel (420') by a second additional joining zone (423'); a first additional secondary leg (426') and a second additional secondary leg (428') substantially rectangular, the first additional secondary leg (426') being directly connected to an additional lateral edge (422b-2') of the first additional secondary flap (422') and is connected to the first additional secondary flap (422') by a third additional joining zone (425'), the second additional secondary leg (428') being directly connected to an additional lateral edge (424b-2') of the second additional secondary flap (424') and is connected to the first additional secondary flap (422') by a fourth additional joining zone (427'); and an additional tertiary panel (430') of substantially rectangular shape, the additional tertiary panel (430') comprising a first circumferential edge directly connected to a second additional circumferential edge (420a-2') of the panel additional secondary panel (420') opposite the first additional circumferential edge (420a-1') by a fifth additional junction zone (429'), wherein: - the sum of the axial dimension (L1) of the first circumferential edge (420a-1), the axial dimension (L2-1) of the first secondary panel (422) and the axial dimension (L2-2) of the second secondary panel (424) is greater than or equal to the axial dimension (L3) of the tertiary panel (430), - the sum of the axial dimension (LT) of the first additional circumferential edge (420a-1'), the axial dimension (L2-1') of the first additional secondary panel (422') and the axial dimension (L2-2') of the second additional secondary panel (424') is greater than or equal to the axial dimension (L3') of the additional tertiary panel (430'),- the circumferential dimension (Hl-1) of the first secondary leg (426) and / or the circumferential dimension (H 1-2) of the second secondary leg (428) is between 80% and 100% of the circumferential dimension (H2) of the tertiary panel (430), and - the circumferential dimension (H 1 -1') of the first additional secondary leg (426') and / or the circumferential dimension (H 1-2') of the second additional secondary leg (428) is between 80% and 100% of the circumferential dimension (H2') of the additional tertiary panel (430').,

4. Pattern (400) according to the preceding claim, in which the secondary panel (420), the first secondary flap (422), the second secondary flap (424), the first secondary tab (426), the second secondary tab (428) and the tertiary panel (430) form a symmetrical intrados assembly with respect to the circumferential median (Y).

5. A pattern (400) according to claim 3 or 4, wherein the additional secondary panel (420'), the first additional secondary flap (422'), the second additional secondary flap (424'), the first additional secondary tab (426'), the second additional secondary tab (428') and the panel additional tertiary (430') form an extrados assembly symmetrical with respect to a circumferential axis (Y') parallel to the circumferential median (Y), said circumferential axis (Y') being separated by an axial distance (d) from the circumferential median (Y).

6. A pattern (400) according to any one of claims 3 to 5, wherein the corners (430a-2, 430a-3) at the ends of the first circumferential edge (430a-1) of the tertiary panel (430) are rounded such that said corners (430a-2, 430a-3) each comprise a circular arc (C) of between 10.5mm and 12.5mm and the corners (430a-2', 430a-3') at the ends of the first further circumferential edge (430a-1') of the further tertiary panel (430') are rounded such that said corners (430a-2', 430a-3') each comprise a further circular arc (C') of between 10.5mm and 12.5mm.

7. A pattern (400) according to any one of claims 3 to 6 further comprising a first primary flap (412) and a second primary flap (414) substantially rectangular, the first primary flap (412) being directly connected to a first length of the primary panel and is connected to the primary panel (410) by an upstream primary junction area (411), the second primary flap (414) being directly connected to a second length of the primary panel and is connected to the primary panel (410) by a downstream primary junction area (413).

8. A method of manufacturing an axial protection and retention member by shaping comprising the successive steps of: a. obtaining a metal sheet; b. cutting said metal sheet according to the pattern (400) according to any one of claims 3 to 7; c. stamping and shaping the primary panel (410) so that said primary panel (410) cooperates in shape with the blade root; d. shaping the tertiary panel (430) according to the fifth junction zone (429) and the additional tertiary panel (430') according to the fifth additional junction zone (429') so that the fifth junction zone (429) and fifth zone additional junction (429') are curved circumferentially towards the axial median (X); e. conforming the first secondary flap (422) along the first joining zone (421), the second secondary flap (424) along the second joining zone (423), the first additional secondary flap (422') along the first additional joining zone (421'), the second additional secondary flap (424') along the second additional joining zone (423'), so that the first joining zone (421) and the second joining zone (423) are curved towards the tertiary panel (430) and the first additional joining zone (421') and the second additional joining zone (423') are curved towards the additional tertiary panel (430'); f. shaping the first secondary leg (426) along the third joining area (425), the second secondary leg (428) along the fourth joining area (427), the first additional secondary leg (426') along the third additional joining area (425'), the second additional secondary leg (428') along the fourth additional joining area (427'), so that the third joining area (425) and the fourth joining area (427) are curved towards the tertiary panel (430) and the third additional joining area (425') and the fourth additional joining area (427') are curved towards the additional tertiary panel (430'), the first secondary leg (426), the second secondary leg (428) and the tertiary panel (430) cooperating together, the first additional secondary leg (426'), the second additional secondary leg (428') and the additional tertiary panel (430') cooperating together, the first secondary flap (422), the second secondary flap (424), the first secondary leg (426), the second secondary leg (428) and the tertiary panel (430) delimiting a blocking volume (700), and the first additional secondary panel (422'), the second additional secondary panel (424'), the first additional secondary leg (426'), the second additional secondary leg (428') and the additional tertiary panel (430') delimiting an additional blocking volume (700').

9. Method according to the preceding claim, wherein step (b) consists of cutting said metal sheet according to the pattern (400) according to claim 7, said method further comprising the additional step of conforming the first primary flap (412) according to the upstream primary junction zone (411) and the second primary flap (414) according to the downstream primary junction zone (413), so that the upstream primary junction zone (411) and the downstream primary junction zone (413) are curved towards the circumferential median (Y).

10. Turbine, such as a low pressure turbine, for an aircraft turbomachine with a longitudinal axis comprising a wheel (14) according to any one of claims 1 to 2.

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