Fixed turbomachine vane comprising variable-pitch blades

Abstract

A blade (7) of a static blade of a turbomachine, comprising: - a blade root (11) comprising a first portion (11a) configured to be fixed on a hub (8) of the turbomachine and a second portion (11b) extending radially from the first portion; - a first and a second base (14, 15) extending on either side of the second portion and configured to transmit forces between the blade and the hub, the first and the second base each comprising a first support (14a, 15a) mounted on the first portion at a distance from the second portion or the hub, a second support (14b, 15b) mounted on the second portion (11b), and a connecting flange (14c) connecting the two supports; and - a platform (20) comprising a radially internal portion (20b) mounted on all or part of the first supports and a radially external portion (20a) mounted on the second portion. Figure for the abstract: Fig. 2A

Description

Title of the invention: Fixed turbomachine vane comprising variable-pitch blades Technical field

[0001] The present invention relates to the field of turbomachines, in particular a fixed blading of a turbomachine, for example a fixed blading comprising variable-pitch stator blades, each fixed to a pivot. The invention applies in particular to the unducted rectifier of a turbomachine or to the ducted rectifier of a turbomachine. STATE OF THE ART

[0002] Turbomachines comprising at least one unducted propeller are known by the English term "open rotor" or "unducted fan". Such turbomachines may comprise two unducted and contra-rotating propellers (known by the English acronym CROR for "Contra-Rotating Open Rotor") or a single unducted propeller and a rectifier comprising several stator blades (known by the English acronym USF for "Unducted Single Fan"). The propellers may be placed at the rear of the gas generator (or engine) so as to be of the pusher type or at the front of the gas generator so as to be of the tractor type. These turbomachines are turbo-propellers which are distinguished from turbojets by the use of a propeller outside the nacelle (unducted) instead of an internal fan.This makes it possible to increase the dilution ratio significantly without being penalized by the mass of the casings or nacelles intended to surround the propeller or fan blades.

[0003] The stator vanes of the rectifier are generally installed on a hub which carries the separation nozzle of the primary and secondary flows circulating respectively in a primary vein and around the inlet casing. Unlike the upstream propeller of a USF type turbomachine, the stator vanes of the rectifier are fixed in rotation relative to the axis of rotation of the upstream propeller and consequently do not undergo centrifugal force.

[0004] The stator blades extend from the inlet casing and may, if necessary, be variable-pitch. In this case, each stator blade root is pivotally mounted along a pitch axis and connected to a pitch-changing system mounted in the turbomachine. However, the integration zone of the stator blade root and pivot is an area that is highly constrained by the presence of numerous pieces of equipment around them.

[0005] Current propeller fixing technologies, however, do not meet the need for fixing the stator blades of a turbomachine because they use centrifugal force. generated by the rotation of the propeller to press the foot of the blade into its attachment. However, in a static blade, the absence of rotation and therefore of centrifugal force prevents the use of this means of attachment.

[0006] The blades of the static blades are therefore generally fixed by bolting on a metal attachment comprising bolts extending either axially or radially, so as to fix the blade root to the attack. This type of attachment is however bulky tangentially, in particular when the bolts are mounted radially, which poses difficulties of integration in the turbomachine.

[0007] Furthermore, the attachment is subjected to significant bending forces and the areas of the blade root into which the bolts are introduced form stress concentration zones which undergo an asymmetrical force due to the pressure differences experienced by the intrados and the extrados of the blade. EXPOSED

[0008] An aim of the present application is to remedy the aforementioned drawbacks, by proposing a system for fixing the blades of a static blading of a turbomachine, the size of which is reduced while guaranteeing suitable support of the blades of the static blading.

[0009] For this purpose, according to a first aspect, a blade of a static blade of a turbomachine is proposed, comprising:

[0010] - a blade root comprising a first portion configured to be fixed on a hub of the turbomachine and a second portion extending radially from the first portion relative to an extension axis of the blading;

[0011] - a first and a second base extending on either side of the second portion and configured to transmit forces between the blade and the hub, the first and second bases each comprising a first support configured to be mounted on one of the first portion of the blade root at a distance from the second portion and the hub, a second support configured to be mounted on the second portion of the blade root at a distance from the first portion and the first support, and a connecting flange connecting the first support and the second support; and

[0012] - a platform comprising a radially internal part mounted on all or part first supports and a radially external part mounted on the second portion of the blade.

[0013] Some preferred but non-limiting features of the above-described blade are the following, taken individually or in combination: - the first and second portions of the blade root are connected by a junction having a radius of curvature, the second support of the first base and of the second base being fixed to the blade root in an area of ​​the second portion positioned radially at a distance from the junction, and the first support of the first base and the second base being fixed to the first portion or to the hub in an area at a tangential distance from the junction. - the first support of the first and second bases is mounted on the first portion of the blade root such that a free edge of the first support is closer to a free end of the first portion of the blade root than to the junction. - the first support of the first and second base is mounted on the hub, at a distance from the first portion of the blade root. - the blade comprises several first bases and several second bases, for example at least two and at most four first and second bases, the first and second bases extend along the blade, between a leading edge and a trailing edge of the blade. - the blade comprises first fastening members configured to fasten the first supports to the hub, and second fastening members configured to fasten the second supports to the second portion of the blade root. - the first and second supports each have a free edge, all or part of the free edges of the first supports and the second supports being chamfered. - the platform is either monolithic with at least one of the first and second bases, or attached and fixed to at least one of the first and second bases by means of third fixing members.

[0014] The invention also relates to a blading of a turbomachine comprising at least one blade as defined previously and a hub, the blade being mounted in the hub by means of first fixing members.

[0015] Advantageously, the blade is mounted in the hub by means of an attachment, the attachment being pivotally mounted relative to the hub around a radial wedging axis. DESCRIPTION OF FIGURES

[0016] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0017] [Fig.l] illustrates a schematic view, in axial and partial section, of an example of a turbomachine which may comprise a blade of a static blading according to one embodiment;

[0018] [Fig.2A] is a schematic sectional view of an exemplary embodiment of a blade of a static blading according to a first embodiment; and

[0019] [Fig.2B] is a schematic sectional view of an exemplary embodiment of a blade of a static blading according to a second embodiment.

[0020] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION

[0021] A turbomachine 1, in particular for an aircraft, conventionally comprises at least one fan or at least one propeller 2, a compression section 3, a combustion chamber 4, a turbine section 5 downstream of the combustion chamber 4, and an exhaust casing.

[0022] The invention applies to any static (i.e. non-rotating) blading 6 of a turbomachine 1, whether it is a rectifier blading 6 of a fan or a propeller 2, a rectifier blading 6 of the compression section 3, or a distributor blading 6 of the turbine section 5. By way of example, the turbomachine 1 may in particular be a USF type turboprop comprising an unducted propeller 2, in which case the static blading 6 is unducted and extends downstream of the propeller 2 (see [Fig.l]). In another example, the turbomachine 1 may be a turbojet comprising a ducted fan, in which case the static blade 6 may correspond to the ducted rectifier extending downstream of the fan which is known by the English designation “outlet guide vane”.

[0023] In the present application, upstream and downstream are defined relative to the direction of flow of the gases through the static blading 6. The axis X is the axis of rotation around the rotor of the propeller 2 (respectively, of the fan). The axial direction corresponds to the direction of the X axis and a radial direction is a direction perpendicular to this X axis and passing through it. Furthermore, the circumferential (or tangential) direction corresponds to a direction perpendicular to the X axis and not passing through it. Unless otherwise specified, internal and external are used with reference to a radial direction so that the internal part or face of an element is closer to the X axis than the external part or face of the same element.

[0024] The blade 7 will thus be defined relative to the axis X of the rotor associated with the static blade 6 (whether it is the axis of rotation of the fan or of the propeller 2 for a fan rectifier, the axis of rotation of the compressor rotor for a compression section rectifier 3 or even the axis of rotation of the turbine rotor for a turbine section distributor 5 on which it is intended to be mounted).

[0025] Optionally, the blade 7 is variable-pitch, that is to say that the blades 7 are pivotally mounted about a pitch axis Y on a hub 8 of the blade 6 (the pitch axis Y being fixed relative to the axis X). This is not, however, limiting, the blades 7 being able to be fixed relative to the hub 8 when the fan is shrouded, the hub 8 then corresponding to the shell of the intermediate casing (which is located between the low pressure compressor casing and the high pressure compressor casing).

[0026] The static blading 6 thus comprises a hub 8 mounted fixedly relative to a casing 9 of the turbomachine 1. It is therefore non-rotating. The blades 7 of the blading 6 extend substantially radially relative to the axis X.

[0027] In an embodiment in which the blades 7 are variable-pitch, the blade 6 comprises an actuating mechanism 10 for modifying the pitch angle of the blades 7 of the blade 6 in order to adapt the performance of the turbomachine 1 to the different flight phases. In addition, the root 11 of each blade 7 is mounted in the hub 8 by means of a fastener 8a (or pivot). The fastener is rotatably mounted relative to the hub 8 about a pitch axis Y. More precisely, the fastener is rotatably mounted inside a housing provided in the hub 8, by means of rolling elements such as balls or any other element capable of performing this function.

[0028] In the remainder of the description, for the sake of simplicity, the invention will be described in the case of a variable-pitch blade 7 whose root is mounted in the hub 8 by means of the attachment 8a. However, the present description is not limited to this configuration and applies mutatis mutandis to a fixed blade 7 whose root is mounted directly on the hub 8.

[0029] The blade 7 comprises a blade 12 with an aerodynamic profile suitable for being placed in an air flow when the turbomachine 1 is in operation in order to generate lift, as well as a blade root 11 configured to be fixed to the hub 8 of the blading 6.

[0030] The blade 7 is shaped so as to define a lower surface 7a, an upper surface 7b, a leading edge and a trailing edge. In a manner known per se, the leading edge is configured to extend opposite the flow of gases entering the turbomachine 1. It corresponds to the front part of an aerodynamic profile which faces the air flow and which divides the air flow into an lower surface flow and an upper surface flow. The trailing edge corresponds to the rear part of the aerodynamic profile, where the lower and upper surfaces flow meet.

[0031] The blade root 11 comprises a first portion 11a configured to be fixed to the hub 8 via the attachment 8a, and a second portion 11b extending radially relative to the axis X from the first portion 11a. The second portion 11b is therefore connected to the blade 12, possibly monolithically.

[0032] In a first embodiment, the blade 7 comprises a composite material comprising a fibrous reinforcement embedded in a matrix, for example a polymer matrix. The fibrous reinforcement may comprise woven or knitted three-dimensional fibrous arrangements. It is furthermore produced in such a way that it comprises warp yarns that extend continuously both within the airfoil blade portion 12 and within the blade root portion 11. Alternatively, the fiber reinforcement may comprise laminated two-dimensional fiber arrangements. The fibers of the fiber reinforcement comprise at least one of the following materials: carbon (typically, silicon carbide), glass, aramid, polypropylene, and / or ceramic (typically, an oxide ceramic). The matrix typically comprises an organic matrix (thermoset, thermoplastic, or elastomer) or a carbon matrix. For example, the matrix comprises a plastic material, typically a polymer, for example, epoxy, bismaleimide, or polyimide.

[0033] The fiber reinforcement may in particular comprise two skins, which are connected to each other and extend generally opposite each other. In particular, the skins are connected at the blade head over the entire chord of the blade 7, at the leading edge and at the trailing edge. The skins may be monolithic and be made in one piece from a fiber preform with varying thickness. Alternatively, a first skin may be formed from a first portion of the fiber reinforcement in order to form the intrados and a second skin may be formed from a second portion of the fiber reinforcement in order to form the extrados, the first and second portions of the reinforcement then being connected, for example near the blade head.

[0034] A delinking is then produced in the fibrous reinforcement, at the level of the radially internal end of the skins opposite the head of the blade, so that this end is free. The radially internal ends of the skins then form the first portion 11a and are spaced apart from each other so as to extend tangentially against the attachment 8a. The radially internal ends of the skins each have a free end 11e. The free end 11e of the skin intended to form the intrados face 7a of the blade 7 extends on one side of the second portion 11b and forms an intrados part of the root 11, while the free end 11e of the skin intended to form the extrados face 7b of the blade 7 extends on the other side of the second portion 11b and forms an extrados part of the root 11.

[0035] Alternatively, the blade 7 is made of metal: in this case, the blade root 11 is shaped so that its radially internal end comprises a lower surface portion and an upper surface portion which flare out from the second portion so as to extend substantially tangentially against the attachment to form two sections, each section having a free end 11e extending on the lower surface or upper surface side, respectively.

[0036] The first and second portions 11a and 11b of the blade root 11 are connected by a junction 11d. In one embodiment, and in particular when the blade 7 is made of composite material, the junction 11d has a radius of curvature R in order to limit the risk of breakage between the first portion 11a and the second portion 11b during transmission of forces between the two, in particular by minimizing out-of-plane and shear stresses. The fastener 8a comprises an external surface 8b configured to receive the first portion 11a. The first portion 11a is thus arranged against the external surface 8b.

[0037] The blade 7 further comprises a first base 14 and a second base 15 extending on either side of the second portion 11b of the blade root 11. For example, the first base 14 is arranged on the intrados side of the blade root 11 and the second base 15 is arranged on the extrados side of the blade root 11. The first base 14 and the second base 15 are configured to transmit forces between the blade 7 and the hub 8 (via the attachment 8a).

[0038] In one embodiment, the blade 7 may comprise several first bases 14 and several second bases 15. For example, the blade 7 may comprise at least two first and two second bases 14 and 15. Taking into account the usual length (chord) of the stator blades 7, the blade 7 may comprise at most four first and four second bases 14 and 15. For example, the blade comprises three first and three second bases 14 and 15. The first bases 14 and the second bases 15 are then substantially identical to each other. In all embodiments with several first and second bases 14, 15, the first bases 14 and the second bases 15 are arranged so as to extend along the blade 7 between the leading edge and the trailing edge, i.e. along the chord of the blade 7.The first bases 14 may for example be arranged on the intrados side 7a of the blade root 11 and the second bases 15 on the extrados side 7b of the blade root 11. In other words, the first bases 14, respectively the second bases 15, are substantially aligned along the blade root 11a between the leading edge and the trailing edge. Preferably two successive first bases 14 or two second bases 15 along the blade root 11 are then spaced apart by a constant distance, in order to uniformly distribute the absorption of forces along the blade root 11.

[0039] The first base 14 and the second base 15 each comprise a first support 14a, 15a, a second support 14b, 15b, and a connecting flange 14c, 15c, extending between the first and second supports 14a, 14b, 15a, 15b of the base 14, 15.

[0040] The second support 14b, 15b of each of the bases 14, 15 is mounted on the blade 7, and more precisely mounted on the second portion 11b of the blade root 11. In particular, the second support 14b, 15b of each base 14, 15 can be fixed to the second portion 11b of the blade root 11 by fixing members 16 such as bolts, rivets or any other equivalent fixing means. In order to limit the number of parts and to uniformly distribute the force absorption, the first and second bases 14 and 15 and their first supports 14a, 15a are preferably arranged symmetrically with respect to the blade root 11, that is to say opposite each other. In addition, in this configuration, the same fixing member 16 can secure the second supports 14b, 15b of a first and a second base 14, 15 opposite each other, the second fixing member 16 being for example mounted through said second supports 14b, 15b and the second portion 11b of the blade root 11.

[0041] The first support 14a, 15a of each of the bases 14, 15 is configured to be secured to the hub 8 via the attachment 8a using fixing members 13. More specifically, in a first embodiment, an example of which is illustrated in [Fig.2A], the first support 14a, 15a of each of the bases 14, 15 is mounted directly on the hub 8 (here, via the attachment 8a) and in a second embodiment, an example of which is illustrated in [Fig.2B], the first support 14a, 15a of each of the bases 14, 15 is mounted on the hub 8 (here, via the attachment 8a) via the first portion 11a of the blade root 11.

[0042] The fixing members 13 are therefore configured to secure the first portion of the blade 7 to the hub 8 (via the fastener 8a). In one embodiment, the fixing members 13 are configured to fix the first portion 11a to the external surface 8b of the fastener 8a. For example, the fixing members 13 comprise screws, bolts, or any other suitable fixing member radially fixing the first portion 11a to the external surface 8b. In one embodiment, the fixing members secure the blade 7 to the hub 8 (via the attachment 8a) on either side of the blade root 11, that is to say that one or more fixing members 13a fix for example the intrados part of the first portion 11a on the external surface 8b, and that one or more fixing members 13b fix the extrados part of the first portion 11a on the external surface 8b.

[0043] Thus, each of the bases 14 and 15 are configured to take up a majority of the forces between the blade 7 and the hub 8 (via the attachment 8a), so that these forces no longer pass through the junction 11d, which reduces the stress concentrations in the part of the blade 7 which is the most fragile. This in particular distributes the transmitted forces and limits the magnitude of the stresses in these risk zones of the blade root 11, and therefore reduces the risk of breakage of the blade root 11.

[0044] Furthermore, in order to increase the volume of forces that can be transmitted by the bases 14, 15, the second support 14b, 15b of each of the bases 14, 15 is mounted on the second portion 11b of the blade root 11 so as to extend as far as possible from the junction 11d. The second support 14b, 15b therefore extends at a distance from the first portion 11a and from the junction 11d. More precisely, these second supports 14b, 15b are fixed to the blade root 11 in areas of the second portion 11b positioned radially at a distance from the junction 1 Id.

[0045] Similarly, still to protect the junction 11d, the first supports 14a, 15a of each of the bases 14, 15 can be fixed to the attachment 8a, if necessary via the first portion 11a so as to extend as far as possible from the junction 11d (taking into account the constraints of integration of the attachment 8a in the blading 6). The first support 14a, 15a therefore extends at a distance, in a tangential direction, from the junction 11d. In this way, the transmission of forces between the two portions 11a and 11b of the blade root 11 via the junction 11d, which is at high risk of breakage, is limited. It will be understood here that the fixing of the first supports 14a, 15a directly on the hub 8 (via the attachment 8a) makes it possible to move these first supports 14a, 15a further away from the junction 11d; however, the size of the second embodiment, where the first supports 14a, 15a are fixed on the first portion 11a of the blade root 11 is smaller.

[0046] In one embodiment, each of the supports 14a, 14b, 15a, 15b of the bases 14, 15 comprises a fixing plate 17a, 17b. Where appropriate, the supports 14a, 14b, 15a, 15b may further comprise a reinforcing rib 18 configured to stiffen the bases 14, 15 and limit their deformation during the transmission of forces to the hub 8 (via the attachment 8a). Each reinforcing rib 18 then connects the connecting flange 14c, 15c to the fixing plate 17 of the supports of the base 14, 15. More precisely, each of the first supports 14a, 15a may comprise a first reinforcing rib 18a connecting the connecting flange 14c, 15c to the fixing plate 17a, and each of the second supports 14b, 15b may comprise a second reinforcing rib 18b connecting the connecting flange 14c, 15c to the fixing plate 17b.

[0047] The fixing plate 17a of each of the first supports 14a, 15a matches the external surface 8b of the attachment 8a. The securing of the first support 14a, 15a to the hub 8 (via the attachment 8a) directly or via the first portion 11a is carried out using fixing members 19 such as bolts, screws or any other equivalent means. In particular, in the embodiment in which the first supports 14a, 15a are fixed to the hub 8 (via the attachment 8a) via the first portion 11a of the blade root 11, the fixing members 19 of the supports can be shared with the fixing members 13 of the first portion 11a of the root 11 to the hub 8 (via the attachment 8a), in order to limit the number of parts. Thus, the fixing plate 17a is arranged directly on the hub 8 (via the fastener 8a) or on the first portion 11a.

[0048] On the other hand, the fixing plate 17b of each of the second supports 14b, 15b matches the opposite face of the second portion 11b of the blade root 11. The fixing of the second support 14b, 15b to the second portion 11b of the blade root 11 is produced using the fixing members 16.

[0049] In one embodiment (not visible in the figures), each of the supports 14a, 14b, 15a, 15b has at least one chamfered free edge in order to gradually transmit the forces to the blade 7 and to the hub 8 (via the attachment 8a) and thus not to create a stress break. For example, each of the tangential free edges of the first supports 14a, 15a and the radial free edges of the second supports 14b, 15b is chamfered. By chamfered, it is meant that the thickness of the thickness of the free edge is gradually reduced in the direction of its free end 11e. The free end 11e of the free edge is therefore thinner.

[0050] In the first embodiment (see for example [Fig.2A]), the fixing plate 17a of the first supports 14a, 15a is fixed in an area tangentially distant from the blade root 11, in order to be able to transmit more forces to the hub 8 (via the attachment 8a). Thus, the first support 14a, 15a is mounted on the attachment 8a tangentially at a distance from the first portion 11a of the blade root 11.

[0051] In the second embodiment (see for example [Fig.2B]), the first support 14a, 15a is mounted on the first portion 11a so that the free edge of this first support 14a, 15a which is closest to the Y axis extends at a distance from the junction 11d. For this, the opposite free edge, that is to say the free edge of the first support 14a, 15a which is furthest from the Y axis of the blade, is closer to the free end 11c of the first portion 11a of the blade root 11 than to the junction 11d. In one embodiment, the opposite free edge can be placed in line with the free end 11c of the first portion 11a. Thus, the distance between the first support 14a, 15a and the junction 1 Id of the blade root 11 is as great as possible, which increases the quadratic moment as well as the recovery of the forces coming from the blade 7.This embodiment also makes it possible to reduce the tangential size of the blade root attachment 11 in comparison with the first embodiment.

[0052] Finally, the blade 7 comprises a platform 20 configured to delimit a flow vein passing through the blade 7. The platform 20 comprises a radially external portion 20a mounted on all or part of the first supports 14a, 15a and a radially internal portion 20b mounted on the second portion 11b of the blade root 11. In one embodiment, the platform 20 comprises only a radially external portion 20a, extending on either side of the second portion 11b. Alternatively, the platform 20 may comprise a first radially external portion 20a fixed on the intrados face 7a of the blade 7 and a second radially external portion 20a fixed on the extrados face 7b of the blade. Similarly, the platform may comprise a single radially internal portion 20b, which is fixed to one of the first and second bases 14, 15, so as to optimize the distribution of stresses and play on the stiffness of the platform for frequency positioning where appropriate. Alternatively, the platform may comprise a first radially internal part 20b fixed on the first base 14 and a second radially internal part 20b fixed on the second base 15.

[0053] In a first embodiment, the platform 20 is attached and fixed to at least one of the bases 14, 15, preferably to each base 14, 15.

[0054] The radially external portion 20a is mounted on the second portion 11b of the blade 7, and comprises a flat surface 21 delimiting the flow stream and extending in a tangential direction. The flat surface 21 is therefore substantially parallel to the external surface 8b. The flat surface 21 is furthermore located radially opposite the hub 8 relative to the bases 14, 15. In one embodiment, the radially external portion 20a further comprises at least one fixing tab 22 configured to fix the radially external portion 20a on the second portion 11b of the blade root. For example, the fastening tab 22 may extend radially from an inner face of the planar surface 21 or form a radially bent end inside the planar surface 21. The fastening tab 22 extends along the chord of the blade 7.

[0055] In one embodiment, the fixing tab 22 is in contact with the second support 14b, 15b of the corresponding base 14, 15. Thus, it is possible to use the fixing members 16 to fix both the base 14, 15 and the platform 20 to the second portion 11b of the blade root 11. When the blade 7 comprises several bases 14, 15, the platform 20 may comprise a fixing tab 22 per base 14, 15, in order to stiffen the platform 20. Alternatively, the platform 20 may only comprise fixing tabs 22 at the bases 14, 15 placed near the leading edge and the trailing edge of the blade 7.

[0056] In one embodiment, in particular the flat surface 21 is also in contact with the second portion 11b so as to limit leaks or entry of air from the flow stream towards the first portion 11a of the blade root 11. A seal may be arranged between an external radial end of the second supports 14b, 15b and the flat surface 21, so as to seal the stream and protect the second portion 11b.

[0057] The radially internal part 20b is mounted on all or part of the first supports 14a, 15a, and comprises at least one connection flange 23 connecting the flat surface 21 and the first support 14a, 15a of the corresponding base 14, 15. In one embodiment, the radially internal part 20b comprises as many connection flanges 23 as there are bases 14, 15 in order to stiffen the platform 20.

[0058] More precisely, the radial flange 23 comprises an external end fixed to the flat surface 21 and an internal end, opposite the external end and fixed to the first support 14a, 15a of the base 14, 15 using fixing members 24, which may include bolts in particular. Where appropriate, the internal end may be at the reinforcing rib 18a of the first support 14a, 15a, in order to limit the risk of breakage of the base 14, 15.

[0059] In one embodiment, the connecting flange 23 comprises reinforcing ribs 25, at their internal and external ends.

[0060] For example, the platform 20 is made of a plastic or metallic material, for example polyetheretherketone (PEEK), polyetherimide (PEI), aluminum-based alloy or even composite material.

[0061] In a second embodiment, the platform 20 is monolithic with at least one of the bases 14, 15.

[0062] The invention thus makes it possible to reduce the tangential and radial size at the blade root, while preserving the integrity of the blade root by ensuring the absorption of forces between the blade and the hub.

Claims

Claims

1. Blade (7) of a static blade (6) of a turbomachine, comprising: - a blade root (11) comprising a first portion (11a) configured to be fixed on a hub (8) of the turbomachine and a second portion (11b) extending radially from the first portion (11a) relative to an extension axis (X) of the blade (6);- a first and a second base (14, 15) extending on either side of the second portion (11b) and configured to transmit forces between the blade (7) and the hub (8), the first and the second base (14, 15) each comprising a first support (14a, 15a) configured to be mounted on one of the first portion (11a) of the blade root (11) at a distance from the second portion (11b) and the hub (8), a second support (14b, 15b) configured to be mounted on the second portion (11b) of the blade root (11) at a distance from the first portion (11a) and the first support (14a, 15a), and a connecting flange (14c) connecting the first support (14a, 15a) and the second support (14b, 15b); and - a platform (20) comprising a radially internal part (20b) mounted on all or part of the first supports (14a, 15a) and a radially external part (20a) mounted on the second portion (11b) of the blade (7).;

2. Blade (7) according to claim 1, in which the first and second portions (11a, 11b) of the blade root (11) are connected by a junction (11d) having a radius of curvature (R), the second support (14b, 15b) of the first base (14) and of the second base (15) being fixed to the blade root (11) in an area of ​​the second portion (11b) positioned radially at a distance from the junction (11d), and the first support (14a, 15a) of the first base (14) and of the second base (15) being fixed to the first portion (11a) or to the hub (8) in an area at a tangential distance from the junction (11d).

3. Blade (7) according to claim 2, in which the first support (14a, 15a) of the first and second bases (14, 15) is mounted on the first portion (11a) of the blade root (11) so that a free edge of the first support (14a, 15a) is closer to a free end (11c) of the first portion (11a) of the blade root (11) than to the junction (11d).

4. A blade (7) according to any one of claims 1 to 3, wherein the first support (14a, 15a) of the first and second bases (14, 15) is mounted on the hub (8), at a distance from the first portion (11a) of the blade root (11).

5. Blade (7) according to one of claims 1 to 4, comprising several first bases (14) and several second bases (15), for example at least two and at most four first and second bases (14, 15), the first and second bases (14, 15) extending along the blade (7) between a leading edge and a trailing edge of the blade (7).

6. Blade (7) according to any one of claims 1 to 5, comprising first fixing members (13) configured to fix the first supports (14a, 15a) to the hub (8), and second fixing members (16) configured to fix the second supports (14b, 15b) to the second portion (11b) of the blade root (11).

7. Blade (7) according to any one of claims 1 to 6, in which the first and second supports (14a, 15a, 14b, 15b) each have a free edge, all or part of the free edges of the first supports and the second supports (14a, 15a, 14b, 15b) being chamfered.

8. Blade (7) according to any one of claims 1 to 7, in which the platform (20) is either monolithic with at least one of the first and second bases (14, 15), or attached and fixed to at least one of the first and second bases (14, 15) by means of third fixing members (24).

9. Blading (6) of a turbomachine comprising at least one blade (7) according to any one of claims 1 to 8 and a hub (8), the blade (7) being mounted in the hub (8) by means of first fixing members (13).

10. Blading (6) according to claim 9, in which the blade (7) is mounted in the hub (8) by means of an attachment (8a), the attachment (8a) being pivotally mounted relative to the hub (8) around a radial setting axis (Y).

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