Turbomachine blade, rotor comprising such a blade, and turbomachine comprising such a rotor

Abstract

A turbomachine blade comprising a blade root extending axially between two opposite axial end faces of the blade root. Each axial end face extends in the radial (Y) and transverse (Z) directions and radially between a radially internal end of the blade root intended to be positioned radially opposite a bottom of a rotor disk cavity and a throat (C) of the blade root. The blade comprises two axial end walls extending respectively in line with the two axial end faces. A wall has a radially internal end zone (M1.1) connected to the neck (C) by a connecting zone which includes a concave part (Pcc) connected to the neck (C) and extending transversely and radially outwards away from the neck and, a convex part (Pcv) connected to the radially internal end zone (M1.1) of the wall and extending transversely and radially inwards from the concave part. Fig. 3.

Description

Title of the invention: Turbomachine blade, rotor comprising such a blade and turbomachine comprising such a rotor. Technical field

[0001] The present exposition relates to a turbomachine blade, a turbomachine rotor comprising such a blade, and more particularly to a plurality of such blades and a turbomachine comprising such a turbomachine rotor. Previous technique

[0002] It is known for a turbomachine to have a low-pressure turbine, downstream of a high-pressure turbine, which recovers part of the energy from the combustion of the gases to operate the blower, the compressor(s) and accessories.

[0003] The low-pressure turbine generally comprises an axial arrangement of several stages formed by annular rows or rings of fixed blades and annular rows or rings of blades, called rotating wheels, each arranged between two rows of fixed blades. The rotating blades are generally mounted on the outer periphery of a rotor disk capable of rotating relatively around a longitudinal axis of the turbomachine. More specifically, the rotating blades are mounted by their roots in recesses of this disk which open radially at the outer periphery of the disk and which are designed to receive the blade roots and cooperate with them to ensure their radial retention in these recesses during the rotation of the rotor disk. The recesses are located between teeth arranged circumferentially on the periphery of the rotor disk.

[0004] The movable blades generally extend radially relative to the longitudinal axis of rotation of the rotor disk. The movable blades comprise a blade root for mounting in a cavity of the rotor disk and a blade located in the airflow channel to which the turbine is exposed. The blade comprises, at its base, a platform extending substantially perpendicularly to the radial extension (height) of the blade and a strut connecting the platform to the blade root. The blade root, for example, has a dovetail shape in a cross-sectional view in a plane defined by a radial direction and a transverse or tangential direction, these two directions being perpendicular to the longitudinal axis of rotation of the rotor disk. The blade root extends axially between a first axial end face and a second opposite axial end face, each extending in the radial and transverse directions.The dawn includes, in the part forming Péchasse, two walls or low walls which each extend along the radial and transverse directions, forming respectively a . upstream face and a downstream face of Péchasse which are in alignment with the first and second opposite end faces of the dawn foot.

[0005] The blade foot generally comprises a bulb mounted in the hollow of the cavity and an area located at the radial opening of the cavity, forming a narrowing in cross-section, called the neck, in a plane defined by the radial and transverse directions. The connection area between the radially internal part of each wall and the neck of the blade foot comprises, in a cross-sectional view, a connecting radius.

[0006] It turns out that the radius of connection between the throat and each wall is an area of ​​high concentration of mechanical stress when the turbine is in operation. Depending on the configuration, this area is even the most stressed area of ​​the blade and therefore the most limiting area in terms of lifespan and vibration capacity.

[0007] The inventors have found that the value of the local stress depends strongly on the value of the connecting radius and, more particularly, the smaller the value of the connecting radius, the higher the stress.

[0008] Thus, for good mechanical strength of the blade foot, it is desirable that the value of the radius be as large as possible.

[0009] However, this is not always feasible without adversely impacting the dimensioning of the attachment between the blade and the rotor disk or the control of radial clearances between the blade and the rotor disk.

[0010] To avoid impacting the dimensions of the attachment between the blade and the rotor disk, the connection radius can be increased by shifting the radially inner portion of each wall upwards (i.e., radially away from the blade root). However, such a configuration implies an increase in the radial clearance between the radially inner portion of the wall and the opposing rotor disk tooth. This can result, for example, in increased tangential tilt of the blade and therefore an increased risk of blade root dislodgement (the blade root is located at one end of the blade opposite the blade root) and / or increased leakage, thus causing a decrease in turbine performance.

[0011] Controlling radial clearances between the blade and the rotor disk could be achieved by increasing the height of the rotor disk tooth. However, this is not always possible due to the impact on the dimensions of the attachment between the blade and the rotor disk. Indeed, increasing the mass of the rotor disk tooth affects the stress levels in the throats. This can also lead to increased stiffness on the attachments, which can affect the distribution of forces between the attachment bearing surfaces in the case of a double-bulb blade root configuration.

[0012] There is therefore a real need to reduce the constraints in the connection areas between walls and the necks of the moving turbine blades of turbomachinery by overcoming, at least in part, the aforementioned disadvantages. Description of the invention

[0013] The present description relates, according to a first aspect, to a turbomachine blade comprising a root and a blade extending from the root, the root being intended to be mounted in an open cavity which opens onto an external periphery of a turbomachine rotor disk, the blade extending radially along a radial direction Y relative to a longitudinal axis about which the blade is intended to rotate, the blade extending axially along an axial direction X parallel to the longitudinal axis and transversely along a transverse direction Z perpendicular to the axial X and radial Y directions, the blade root extending axially between a first axial end face of the blade root and a second opposite axial end face of said blade root, each axial end face of the blade root extending along the radial Y and transverse Z directions, each axial end face of the blade root extending radially between, on the one hand,a radially internal end of the blade root intended to be arranged radially opposite a bottom of a rotor disk cavity and, on the other hand, a neck C of the blade root, the neck C of the blade root forming a local narrowing of the cross-section of the blade root along the radial Y and transverse Z directions which is disposed at a radially external position relative to the radially internal end of the blade root, the blade comprising two axial end walls which each extend, at least along the radial Y and transverse Z directions, respectively from the first and second axial end faces of the blade root and radially outwards from them, at least one axial end wall having a radially internal end zone of the axial end wall which is connected to the neck of the blade root by a connecting zone, the connecting zone comprising,a concave portion which is connected to the neck and extends transversely and radially outwards so as to move away from the neck, and a convex portion which is connected to the radially internal end zone of the axial end wall and extends transversely and radially inwards from the concave portion.

[0014] The above configuration of the connection zone between the blade foot and the radially internal zone of the corresponding wall provides an enlarged (more deeply notched) concave portion compared to the previous design (relatively small connection radius) which extends both radially and transversely away from the tooth opposite the rotor disc (and this, on both sides of the blade foot, opposite the two disc teeth which define the cavity between them). receiving the blade root). This enlarged concave section reduces / relieves the mechanical stresses Kt in the connection zone, thus improving the blade's mechanical strength. It should be noted that the cross-section of the blade root is enlarged on both sides of the narrowing (blade root neck), whether moving inwards, towards the radially inner end of the blade root, or outwards, away from this end.

[0015] According to possible characteristics: - the blade foot includes, from the blade foot neck, another concave part comprising a first portion of a circle Cl of radius RI which connects the blade foot neck to a contact point Pc, the contact point Pc being intended to come into contact with an edge of the opening of the cell in which the blade foot is intended to be mounted, the concave part Pcc of the connecting zone comprising a second portion of a circle C2 of radius R2, the radius RI of the first portion of a circle Cl of the other concave part being different from the radius R2 of the second portion of a circle C2 of the concave part Pcc of the connecting zone; - the radii RI and R2 satisfy the relation 0.5 <R2 / Rl<0,95 ; -the blade foot includes, from the blade foot neck, another concave part comprising a first portion of a circle Cl of radius RI which connects the blade foot neck to a contact point Pc' intended to come into contact with an edge of the opening of the cell in which the blade foot is intended to be mounted, the concave part of the connecting area comprising, on the one hand, a portion of a circle Cl' of radius RI which extends the first portion of a circle Cl radially outwards and beyond the blade foot neck and, on the other hand, a second portion of a circle C2' of radius R2' connected to the portion of a circle Cl' at a connecting point Pt' which has a radially external position Pre' relative to the radially internal position Pri of the radially internal end area of ​​the axial end wall; -the convex part of the connection zone is formed by a portion of a circle C3, C3' of radius R3, R3', of reversed curvature with respect to the portions of circles of the concave part Pcc; Pcc', and which connects the concave part Pcc; Pcc' to the radially internal end zone of the axial end wall; -the first portion of circle Cl and the second portion of circle C2 are connected to each other at a connection point Pt which has a radially internal position relative to the radially internal position Pri of the radially internal end zone of the axial end wall; -the awl foot is in the shape of a fir tree foot or in a dovetail joint; -the blade foot includes at least one bulb intended to be mounted in a cavity of a turbomachine rotor disc; - the aven's foot comprises two bulbs.

[0016] The present exposition relates, according to a second aspect, to a turbomachine rotor, comprising a plurality of turbomachine blades as briefly described above.

[0017] The present exposition relates, according to a third aspect, to a turbomachine, comprising a turbomachine rotor as briefly described above.

[0018] The characteristics and advantages of the moving turbine blade of turbomachinery mentioned above apply to the rotor and to the turbomachine comprising the rotor and will therefore not be repeated.

[0019] In the present exposition, the terms "longitudinal", "transverse", "lower", "upper" and their derivatives are defined with respect to the main direction of the blades; the terms "axial", "radial", "tangential", "inner", "outer" and their derivatives are defined with respect to the main axis (axis of rotation) of the turbomachine; "axial plane" means a plane passing through the main axis of the turbomachine and "radial plane" means a plane perpendicular to this main axis; finally, the terms "upstream" and "downstream" are defined with respect to the circulation of air in the turbomachine.

[0020] In the present description, an element is considered to be "removable" when it is possible to separate the element from the rest of the device without the aid of special tools.

[0021] The aforementioned features and advantages, as well as others, will become apparent from the following detailed description of examples of embodiments of a movable turbine blade for a turbomachine. This detailed description refers to the accompanying drawings. Brief description of the drawings

[0022] The attached drawings are schematic and are intended primarily to illustrate the principles of the exposition.

[0023] On these drawings, from one figure to another, identical elements (or parts of elements) are identified by the same reference signs.

[0024] [Fig-1] Fig. 1 is a partial schematic axial cross-sectional view of a turbine low pressure according to an embodiment of the invention.

[0025] [Fig.2A] The [Fig.2A] is an enlarged schematic perspective view of the foot of a movable blade.

[0026] [Fig.2B] The [Fig.2B] is an enlarged schematic view of the foot of the blade of the [Fig.2A] in cross section in a Y, Z plane, showing the first end face of the blade foot.

[0027] [Fig.3] The [Fig.3] is an enlarged schematic view, in cross section of the wall-collar connection area of ​​the blade foot of figures 2A and 2B according to an embodiment of the invention.

[0028] [Fig.4] The [Fig.4] is an enlarged schematic view, in cross section of the wall-collar connection area of ​​the blade foot of figures 2A and 2B according to another embodiment of the invention.

[0029] [Fig.5] The [Fig.5] is an enlarged schematic cross-sectional view of a double-bulb blade foot. Description of the implementation methods

[0030] To make the explanation more concrete, an example of a low-pressure turbine is described in detail below, with reference to [Fig. 1]. It should be noted that the invention is not limited to this example and that the turbomachine blade of this explanation is applicable to high-pressure turbine blades, fan blades, low-pressure compressor blades, and high-pressure compressor blades. The turbomachine blade can be a blade from an aircraft turbomachine or a land-based turbomachine.

[0031] As shown in [Fig. 1] and designated by the general reference number 10, a low-pressure turbine is arranged, in an aircraft turbomachine, downstream of a high-pressure turbine 12. The terms upstream AM and downstream AV such that the upstream is axially located (considering the X-axis of the turbomachine, which is the axis around which the moving parts of the turbomachine are rotating) on ​​the side from which the general flow of the turbomachine originates, and the downstream is axially located on the side towards which this flow is directed.

[0032] The low-pressure turbine 10 comprises a succession of stages of annular rows of blades, alternating successively, in an axial arrangement, a stage of annular rows of fixed blades 18, called distributors, and a stage of rotating disk 16, and so on. These stages are arranged around the longitudinal axis X of the turbomachine. Each rotating disk 16 carries, on its outer periphery, a plurality of movable blades 14.

[0033] More specifically, each disc 16 comprises, on its outer periphery, circumferentially distributed teeth (the apex of which is referenced 20 in [Fig. 1]) and recesses or grooves (the bottom of which is referenced 22 in [Fig. 1]) arranged between the teeth, and in each of which a blade root (the radially internal end of which is referenced 24 in [Fig. 1]) is mounted. In practice, the blade root is engaged axially (along an axial direction parallel to the longitudinal axis X) in a recess and is retained radially there, for example by a mechanical connection achieved through cooperation between complementary shapes of the blade root and the recess. In the example described, the blade root has, for example, a dovetail shape or a shape similar to a single bulb to ensure its radial retention in the recess. According to one variant, a paddle foot with a dovetail shape A two-bulb design could be considered. Alternatively, a base with a fir tree shape could also be considered.

[0034] The blades 14 extend radially, along a radial direction Y, from the bottoms 22 of the cells where they are mounted, away from the cells, in an annular flow channel 26 of a hot gas flow from an upstream combustion chamber of the turbomachine (not shown in [Fig.1]).

[0035] Each blade 14 comprises, according to its radial dimension, radially from the outside to the inside, a blade 28 disposed in the annular flow channel 26 of the hot gas flow, a platform 30 which extends substantially perpendicularly to the (radial) extension axis of the blade and a strut 32 which connects the platform 30 to the radially internal end blade foot 24.

[0036] Figure 2A is a partial schematic view of a blade 14 which can, for example, be integrated into the low-pressure turbine 10 of Figure 1, in a downstream stage not shown, located in the downdraft. This blade comprises the blade 28, the platform 30, the Péchasse 32, a blade root 34 with the radially internal end 24. The blade 14 also comprises an aerodynamic profile which is formed by two profiled surfaces, the upper surface and the lower surface, each connecting a leading edge BA to a trailing edge BF of the blade.

[0037] As shown in [Fig. 2A], the platform 30 includes an upstream spoiler 36 extending upstream and a downstream spoiler 38 extending downstream. The spoilers extend axially between consecutive turbine stages in order to partially maintain the structural integrity of the annular flow channel 26 between each turbine stage, thereby limiting the radial flow of hot gas into the turbine.

[0038] As shown in [Fig.2A], the blade 14 extends not only radially along the radial direction Y, but also axially along the axial direction X, as well as transversely along a transverse direction Z perpendicular to the axial X and radial Y directions.

[0039] As shown in [Fig.2A], the blade foot 34 extends axially along the axial direction X between a first end face 34a, called the upstream end face, and a second opposite end face 34b, called the downstream end face.

[0040] Each end face 34a, 34b of the blade root extends along the radial direction Y and along the transverse direction Z (this extension defines the width of the blade root), as illustrated in [Fig. 2B], which shows a view, in a plane defined by the directions Y and Z, of the first end face 34a of the blade root 34. In this figure, the partial contour of two consecutive teeth DI and D2 of the rotor disk, which define each other, is schematically represented in dashed lines. the alveolus A in which the blade foot 34 is mounted according to a cross-section of the blade foot - alveolus arrangement.

[0041] Each end face 34a, 34b extends radially, along the radial direction Y, between, on the one hand, the radially internal end 24 of the blade foot 34 intended to be positioned opposite the bottom 22 of the cell A and, on the other hand, a neck C of the blade foot which forms a narrowing of the cross-section (in the Y, Z plane) of the blade foot. Generally, the neck of the blade foot is defined by the area of ​​the blade foot where the cross-section is minimal and which is identified, as in [Fig. 3], by the point Pt. As shown in the figures, the cross-section of the blade foot is enlarged on both sides of the neck, whether in the lower part, towards the end 24 ([Fig. 2B]), or in the upper part, away from the end 24 and towards the wall.

[0042] The neck C of the blade foot is arranged in a radially external position relative to the radially internal position of the end 24 of the blade foot, as illustrated in [Fig. 2B]. The neck C of the blade foot is arranged at a radially external opening, marked O in [Fig. 2B], of the cavity A.

[0043] As shown in Figures 2A and 2B, the blade 14 also includes two end walls or partitions, denoted M1 and M2, each extending, at least in the radial direction Y and the transverse direction Z, respectively from the first and second opposite end faces of the blade foot 34a, 34b, in line with and away from them. The radial wall or partition M1 visible in [Fig. 2B] extends radially from the first end face 34a, in a plane defined by the radial direction Y and the transverse direction Z until it reaches the radially inner face of the platform 30 ([Fig. 2A]). The blade shown in [Fig.2A] is that of a downstream stage of the turbine and the wall M2 has a configuration that is different from that of the wall ML. However, for the majority of turbine blades, the configuration of the wall M2 corresponds to that of the wall M1 which will be described below.

[0044] As shown, for example, in [Fig. 2B], for the wall M1, the latter comprises a so-called radially internal zone which, here, corresponds to the radially internal face of the wall and which extends mainly in a transverse direction, on either side of the neck C of the end face 34a of the blade foot. In [Fig. 2B], the radially internal zone of the wall M1 is illustrated by two portions M1.1 and M1.2 which extend along the transverse direction Z on either side of the neck C, respectively. Each of these portions is considered a radially internal zone of the wall within the meaning of this description. The radially internal zone of the wall M1 is connected to the neck C by a connecting zone described below.

[0045] Figure 3 shows a half-cross-sectional view taken with respect to to the plane of symmetry Ps of the blade foot of [Fig.2B] (the plane Ps extends along the axial X and radial Y directions), the connection zone between the C neck of the blade foot and the radially internal zone of the wall, namely here the portion M 1.1. The connection zone between the C neck and the portion Ml.2 of the wall ([Fig.2B]) is obtained by symmetry from the connection zone of [Fig.3].

[0046] As shown in [Fig. 3], the profile of the tooth DI is shown in solid line, as is that of the blade root 34 and the connection zone between the blade root and the radially internal zone Ml.l of the blade wall. The two profiles of the blade root and the tooth are shown here in contact with each other via a bearing surface 34c of the blade root in contact with a bearing face Dl.l of the tooth. The blade root extends away from the edge of the tooth from the contact point Pc.

[0047] In the present embodiment, the connection zone generally comprises a concave portion Pcc extending transversely (along the transverse direction Z) and radially (along the radial direction Y) outwards (radially external direction) away from the collar C to a radially external position Pre relative to the radially internal position Pri of the beginning of the radially internal zone Ml.l of the wall ML

[0048] The connecting zone also includes a convex portion Pcv which extends transversely (along the transverse direction Z) and radially (along the radial direction Y) inwards (radially internal direction) from the concave portion Pcc, extending the latter so as to join the beginning of the radially internal zone Ml.l of the wall ML

[0049] On [Fig.3], the connection zone of the prior art has been represented in dashed lines. This connection zone comprises, from the neck C of the foot of the blade, a portion of a circle of radius RI' which is extended by a straight portion Ll, tangential to the portion of the circle, until it joins the beginning of the radially internal zone Ml.l (lower face) of the wall Ml, without exceeding the radial internal position Pri of the radially internal zone Ml.l.

[0050] As shown in [Fig.3], the concave part Pcc of the new connection zone extends upwards (along the radial direction Y and away from the throat C) radially beyond the radially internal position Pri and widens, for example in a bulb shape, to reach the radially external position Pre, before descending again to join the radially internal zone Ml.l. This widening of the curvature or radius of connection makes it possible to reduce the mechanical stresses applied in this area of ​​the blade and thus to improve its mechanical strength.

[0051] More particularly, as shown in [Fig. 3], the blade foot includes another concave portion which connects the throat C to the contact point Pc, which takes the form of a portion of a circle of radius RL. The concave portion Pcc of the new zone of The connection includes, starting from the neck C, a second circular portion C2 with a radius R2 different from RI. The radius R2 is adjusted to allow the circular portion C2 to extend radially above the connection zone of the anterior artery and, in particular, radially above the radially internal position Pri. The radius R2 is larger than the radius RI', which allows it to give the concave portion Pcc this enlarged shape, favorable to the reduction of mechanical stresses.

[0052] In a preferred embodiment, the rays RI and R2 satisfy the relation 0.5 <R2 / Rl<0,95.

[0053] In the present mode, the first circular portion Cl and the second circular portion C2 are joined at a connection point Pt which has a radially internal position relative to the radially internal position Pri of the radially internal zone Ml.l of the wall ML. In this configuration, the tangent between the circular portions Cl and C2 is vertical (radial). This configuration positions the connection point at the level of the throat C of the blade foot, where the cross-section of the blade foot is minimal.

[0054] Furthermore, the convex terminal part Pcv of the connecting zone is formed by a third circular portion C3 of radius R3, with a curvature reversed with respect to that of the first and second circular portions Cl and C2. The third circular portion C3 connects the second circular portion C2 of radius R2 to the radially internal zone Ml.l of the wall Ml whose radial position has not been modified.

[0055] It should be noted that the configuration described above makes it possible to preserve the radial play J ([Fig.3]) between the radially internal zone Ml.l of the wall (lower face) and the radially external zone of the tooth (upper face) and thus to minimize the leakage section.

[0056] In addition, this configuration also makes it possible not to modify the part of the blade foot located radially below the connection point (Pt).

[0057] It should be noted that the configuration described above can also be applied to the wall M2, considering the connection area between this wall and the neck of the blade foot at the level of the downstream end face 34b.

[0058] Fig. 4 illustrates another embodiment of a connection zone between the wall Ml and the neck of the awl foot.

[0059] In this other embodiment, the concave portion Pcc' comprises a circular portion Cl' which extends the circular portion Cl of radius RI of [Fig. 3] and which has the same radius RL. This extension of the circle Cl extends to a connecting point Pt' which has a radially external position Pre' relative to the radially internal position Pri of the radially internal zone Ml.l of the wall ML

[0060] As shown in [Fig. 4], the connection point Pt' which is in a radially more external position than the connection point Pt of [Fig. 3] and is also offset transversely in the transverse direction Z, from the col C of the foot of the blade (in the direction of the plane of symmetry Ps). The portion of the circle Cl' is connected at the point Pt' to a portion of the circle C2' of the concave part Pcc'.

[0061] This connection configuration makes it possible to take into account certain operating conditions whereby, due to the three-dimensional change applied to the blade, the area of ​​maximum stress is not always located at the throat of the blade root, but sometimes in a position radially external to the throat. Thus, the circular portion Cl' of radius RI extends into the area of ​​the blade where the stresses are maximum, thereby reducing them.

[0062] Furthermore, in this connection configuration, the circular portion C2' of the connection zone, which extends the circular portion Cl', has a radius R2' that is smaller than the radius R2 of the circular portion C2 in [Fig. 3] in order to initiate the connection to the radially internal zone Ml.l of the wall Ml, without having to modify the latter, thus preserving the clearance J and minimizing the leakage section. The connection to the radially internal zone Ml.l is made by the third circular portion C3' with a radius R3' smaller than the radius R3 of the third circular portion C3 in [Fig. 3]. These modifications to the radii of the two circular portions C2' and C3', however, have no impact on the stresses since these circles are located outside the zone of maximum stress.

[0063] According to an alternative embodiment not shown in the figures, the circular portion C2' of radius R2' can be subdivided into two circular portions of different radii. This configuration allows for a further increase in local curvature and thus, in some cases, for a further improvement in leakage reduction by reducing the cross-sectional area.

[0064] Moreover, such a variant also makes it possible to limit the leakage in the cavity created by the portion of the circle of radius R2'.

[0065] As shown in [Fig. 5], the movable blade according to the present description can also be a blade 14' whose blade root has two bulbs, each defining a blade root neck, in this case an upper neck Cs and a lower neck Ci. The connection zone described above according to the different embodiments and variants refers here to the upper neck Cs.

[0066] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than a restrictive sense.

Claims

1. Demands Turbomachine blade (14) comprising a foot (34) and a blade extending from the foot, the foot being intended to be mounted in an open cavity (A) opening onto an outer periphery of a turbomachine rotor disk, the blade extending radially in a radial direction (Y) relative to a longitudinal axis about which the blade is intended to rotate, the blade extending axially in an axial direction (X) parallel to the longitudinal axis and transversely in a transverse direction (Z) perpendicular to the axial (X) and radial (Y) directions, the blade foot (34) extending axially between a first axial end face (34a) of the blade foot and a second opposite axial end face (34b) of said blade foot, each axial end face of the blade foot extending in the radial (Y) and transverse (Z) directions, each axial end face of the blade foot extending radially between, on the one hand,a radially internal end (24) of the blade root intended to be arranged radially opposite a bottom (22) of a rotor disk cavity and, on the other hand, a neck (C) of the blade root, the neck (C) of the blade root forming a local narrowing of the cross-section of the blade root along the radial (Y) and transverse (Z) directions which is disposed at a radially external position relative to the radially internal end of the blade root, the blade comprising two axial end walls (M1, M2) which each extend, at least along the radial (Y) and transverse (Z) directions, respectively from the first and second axial end faces of the blade root and radially outwards from them, at least one axial end wall (M1) having a radially internal end zone (M1.1) of the axial end wall (M1) which is connected to the Col du Pied d'Aube via a connecting zone,the connection zone comprising, a concave part (Pcc; Pcc') which is connected to the neck (C) and which extends transversely and radially outwards so as to move away from the neck and, a convex part (Pcv; Pcv') which is connected to the radially internal end zone (Ml.l) of the axial end wall (Ml) and which extends transversely and radially inwards from the concave part (Pcc; Pcc').

2. Turbomachine blade according to claim 1, characterized in that the blade foot (34) comprises, from the neck (C) of the blade foot, another concave part comprising a first circular portion (Cl) of radius RI which connects the neck of the blade foot to a contact point (Pc), the contact point (Pc) being intended to come into contact with an edge of the opening of the cavity in which the blade foot is intended to be mounted, the concave part (Pcc) of the connecting zone comprising a second circular portion (C2) of radius R2, the radius RI of the first circular portion Cl of the other concave part being different from the radius R2 of the second circular portion C2 of the concave part (Pcc) of the connecting zone.

3. Turbomachine blade according to claim 2, characterized in that the radii RI and R2 satisfy the relation 0.5 <R2 / Rl<0,95.

4. Turbomachine blade according to claim 1, characterized in that the blade foot (34) comprises, from the neck (C) of the blade foot, another concave portion comprising a first circular portion (Cl) of radius RI which connects the neck of the blade foot to a contact point (Pc') intended to contact an edge of the opening of the cavity in which the blade foot is intended to be mounted, the concave portion of the connecting area comprising, on the one hand, a circular portion (Cl') of radius RI which extends the first circular portion (Cl) radially outwards and beyond the neck of the blade foot and, on the other hand, a second circular portion (C2') of radius R2' connected to the circular portion (Cl') at a connecting point (Pt') which has a radially external position (Pre') relative to the radially internal position (Pri) of the radially internal end area of ​​the axial end wall (Ml).

5. Turbomachine blade according to any one of claims 2 to 4, characterized in that the convex part (Pcv; Pcv') of the connecting zone is formed by a portion of a circle (C3; C3') of radius R3, R3', of reverse curvature with respect to the portions of circles of the concave part (Pcc; Pcc'), and which connects the concave part (Pcc; Pcc') to the radially internal end zone (Ml.l) of the axial end wall (Ml).

6. Turbomachine blade according to any one of claims 2 to 5, characterized in that the first circular portion (Cl) and the second circular portion (C2, Cl') of the concave part (Pcc; Pcc') are connected to each other at a connection point (Pt,

7.

8.

9.

10.

11. C) which has a radially internal position relative to the radially internal position (Pri) of the radially internal end zone (M 1.1) of the axial end wall (Ml). Turbomachine blade according to any one of the preceding claims, characterized in that the blade foot (34) is in the form of a fir tree foot or a dovetail. Turbomachine blade according to the preceding claim, characterized in that the blade foot (34) comprises at least one bulb intended to be mounted in a cavity of a turbomachine rotor disk. Turbomachine blade according to the preceding claim, characterized in that the blade root comprises two bulbs. Turbomachine rotor, comprising a disk centered on an axis (X) and having a plurality of open cavities (A) opening onto an external periphery of the disk and a plurality of turbomachine blades (14) according to any one of the preceding claims, each blade being mounted in a cavity of the disk. Turbomachine, comprising a turbomachine rotor according to the preceding claim.

Images