EP3677752A1 - Improved seal assembly for an inter-blade platform - Google Patents

Abstract

Seal (10) for an inter-blade platform intended to extend circumferentially around an axis and to be mounted between two axial ends of the inter-blade platform, comprising a first part (10a) in contact with a first blade adjacent to a first circumferential end of the platform, and a second part (10b) in contact with a second blade adjacent to a second circumferential end of the platform, the first part (10a) and the second part (10b) of the joint d the seal (10) being linked to each other so that a displacement in the circumferential direction of one of the two parts (10a, 10b) of the seal (10) causes a displacement of the other part (10a, 10b) of the seal (10) in the same direction, when the two parts (10a, 10b) of the seal (10) are connected to each other.

Description

Technical area

The invention relates to an inter-blade platform seal. Such a seal is disposed between a blade and an inter-blade platform separate from the blade, and aims to limit the circulation of air between the blade and the inter-blade platform. Such a seal is used in particular, but not only, in the turbomachine blowers (or fan) between the fan blades and the inter-blade platforms.

Prior art

In a turbomachine, the fan blade platforms must perform several functions. From an aerodynamic point of view, these platforms have the primary function of delimiting the air flow stream. In addition, they must also be able to withstand significant forces by deforming as little as possible and remaining integral with the disc which carries them.

In order to satisfy these different requirements, certain configurations have been proposed in which the platforms have a first part, the vein wall, making it possible to define the air flow vein and to ensure the retention of the platform when the engine is in rotation, and a second part, the box, making it possible to limit the deformations of the first part under the effects of centrifugal forces and to keep the platform in position when the engine is stopped.

A clearance is provided between the platforms and the blades to allow the latter a limited clearance during the different engine operating phases. However, the performance requirements of turbomachines translate into good control of the seal at the foot of the blades. For this, the game is sealed by a seal made of elastomeric material fixed along the side edges of the platform and bearing against the adjacent blade.

We know a linear joint of inter-blade platform as described in the document FR2987086 , having a length, comprising a linear base intended to be fixed to the inter-blade platform, and a linear lip extending from the linear base, said linear lip having a circumferential end configured to contact a wall on the side of a pressure surface or a wall on the side of an upper surface of a blade. This type of seal extends along the lower surface or the upper surface of a blade, including the leading edge and / or the trailing edge.

In configurations where the blades are subjected to significant displacements, in particular due to centrifugal forces, the seals must be designed and finely positioned to ensure a permanent plating against the blades, and thus maintain a good seal. However, it is difficult to find an optimized solution at any point of operation. Indeed, the seal must be both flexible enough to accompany the movement of the blades, but also stiff enough not to turn over or tear off. The materials making it possible to fulfill these conditions can be expensive, and involve shapes, and therefore a complex implementation. In addition, in the event of a large displacement of the blades, this known type of seal may in certain places not properly match the blade in areas of sudden discontinuity or with a small radius of curvature, such as in the vicinity of the leading edge. or the trailing edge of dawn. As a result, air flows between the blade and the inter-blade platform in these areas. The sealing of the air (or gas) stream is therefore not optimal, which deteriorates the performance of the turbomachine.

There is therefore a need for an inter-blade platform seal making it possible to at least partially remedy the drawbacks mentioned above.

Statement of the invention

The present disclosure relates to a seal for inter-blade platform intended to extend circumferentially around an axis and to be mounted between two axial ends of the inter-blade platform, the seal comprising at least a first part configured to be in contact with a first blade circumferentially adjacent to a first circumferential end of the platform, and at least a second part configured to be in contact with a second blade circumferentially adjacent to a second circumferential end of the platform, the first part and the second part of the seal being configured to be connected to each other so that a displacement in a circumferential direction of one of the first or of the second part of the seal causes the first or second part of the seal to move in the same direction from the other, when the first part and the second part of the seal are linked to one another 'other.

It is understood that the seal extends in a preferred direction, the axial direction. This axial direction is not necessarily straight, and is preferably configured to follow the contours of the blade, especially in the vicinity of the discontinuities of the blade. The length of the joint is therefore defined and measured parallel to this axial direction, between the two axial ends of the platform. It is understood that the circumferential direction, or lateral direction, is a direction transverse to the axial direction. When the seal is mounted on a platform, itself mounted on a wheel of a turbomachine fan, the circumferential direction is a direction tangent to the wheel, and perpendicular to the axis of rotation of the fan.

The platform seal has two separate parts from each other. When the seal is mounted on a platform, the two parts of the seal are linked to each other so that the seal extends on either side of the platform in the circumferential direction, from the first circumferential end of the platform to the second circumferential end of the platform. Thus, the first part makes it possible to seal between the platform and the lower surface of a blade, and the second part makes it possible to seal between said platform and the upper surface of a second blade, adjacent to the first dawn. By "related to each other", or integral with each other, it is understood that they are in contact with each other, that is to say communicate with each other for example by being fixed to one other, so that a movement in the circumferential direction of one of the first and second parts, causes a displacement, by reaction, of the other of the first and second parts. In other words, the displacement of one of the first and second parts in the circumferential direction cannot be done without a displacement of the other of the first and second parts in this direction.

Consequently, during a displacement of the blades, for example due to centrifugal forces, a first blade tends to crush the first part of the seal, thus ensuring the seal between said first blade and the platform. Furthermore, a second blade, adjacent to the first and moving in the same direction as the first blade, tends to move away from the platform. However, the force exerted by the first blade on the first part of the joint is transmitted to the second part of the joint, which can thus follow the movement of the second blade. The second part of the seal can therefore seal between the platform and the second blade. Consequently, the seal of the present description can follow the overall movement of the blades, thus making it possible to improve the seal at the foot of the blades, and thus to improve the performance of the turbomachine.

In certain embodiments, the first part of the seal comprises a first contact portion made of an elastomeric material, the first contact portion being configured to be in contact with the first circumferential end of the platform and the first blade adjacent to the first circumferential end of the platform, and the second part of the seal comprises a second contact portion made of an elastomeric material, the second contact portion being configured to be in contact with the second circumferential end of the platform and the second blade adjacent to the second circumferential end of the platform.

The first and second contact portions are configured to be in contact with the platform and a blade adjacent to said platform. The first and second contact portions are therefore arranged at the circumferential ends of the seal, and over the entire length of the latter in the axial direction. Thanks to the first and second contact portions made of elastomeric material, the circumferential ends of the seal are locally more flexible than the portions of the seal other than the contact portions. The contact portions make it possible to better match the contour of the blades, in particular in areas of abrupt discontinuity or with a small radius of curvature of the blade.

In some embodiments, the first portion of the seal includes a first structural portion, and the second portion of the seal includes a second structural portion, the first structural portion and the second structural portion being configured to assemble to each other.

The structural portions make it possible to ensure the rigidity of the joint, and also to transmit the forces exerted on the first contact portion at one circumferential end of the joint, up to the second contact portion at the other circumferential end of the joint.

Furthermore, when the platform is mounted in a turbomachine fan, the first structural portion and the second structural portion can be fixed to one another radially under a vein wall of the platform. The vein wall of the platform is the wall making it possible to delimit the vein for the flow of air entering the blower. By “radially under a vein wall of the platform”, it is understood that the structural portions are arranged on a radially internal face of the vein wall of the platform when the platform is mounted in a blower. The structural portions are therefore arranged on one side of the vein wall opposite the side of the vein wall where the air flows. The fixing of the first structural portion with the second structural portion is therefore carried out radially under the vein wall. According to this configuration, a displacement of the first part of the seal generates a displacement of the second part of the seal, the seal thus moving as a unit by sliding radially under the vein wall of the platform.

In some embodiments, each of the first and second structural portions includes a metallic material.

The fact that the first and second structural portions comprise a metallic material makes it possible to improve the rigidity of the seal, and also to more effectively ensure the circumferential movement of the seal on either side of the platform. The first and the second structural portion may for example have the shape of a metal plate slid radially under the vein wall of the platform.

In certain embodiments, the first contact portion, respectively the second contact portion, is fixed to the first structural portion, respectively to the second structural portion, by being glued along the latter.

Preferably, the first contact portion, respectively the second contact portion, is bonded over the entire length, in the axial direction, of the first structural portion, respectively to the second structural portion.

Alternatively, the first and second contact portions can have a groove extending along said portion in the axial direction, the groove being able to fit at one end of the structural portion. The structural portion can also be embedded in the elastomer, so that the structural portion also comprises an elastomer, integral with the contact portions. These fixing methods allow simple assembly of the different parts of the seal.

In some embodiments, in a cross section parallel to the circumferential direction, the first and second contact portions have a rectangular shape, one side of the rectangle being configured to be in contact with an adjacent blade, another side being configured to be in contact with the platform.

The first and second contact portions are preferably configured to be arranged partially radially under the vein wall. The shape and arrangement of the first and second contact portions make it possible to facilitate the sliding thereof radially under the vein wall, and thus facilitate the displacement of the seal on either side of the platform.

In some embodiments, at least one of the first and second structural portions includes at least one tongue extending in the circumferential direction, a circumferential end of said tongue being configured to come into contact with the other of the first and second structural portion.

By "tongue" is meant a plate having a larger dimension in the circumferential direction than in the axial direction. In other words, the tongue of the first and / or of the second structural portion does not extend over the entire length, in the axial direction, of the seal. When the first part and the second part of the joint are assembled, the circumferential end of the tongue of the first structural portion, for example, comes into contact with the second structural portion. The forces exerted by a blade at one circumferential end of the joint are then transmitted to the other end of the joint via the tongue.

The first structural portion, for example, may also have two or more tabs, the circumferential ends of each of them coming into contact with the second structural portion. Thus, when the first and second parts of the seal are assembled, the seal has the form of a plate comprising windows. The structure of the structural portions comprising tabs makes it easier to assemble the two parts of the seal, in particular the insertion of each of the structural portions under the vein wall. Furthermore, the shape and number of the tongues are not limited, and can be adapted according to the structure of the platform on which the seal is mounted.

In some embodiments, each of the first and second structural portions includes at least one tongue extending in the direction circumferential, a circumferential end of said tongue being configured to come into contact with a circumferential end of the tongue of the other of the first and second structural portions.

Preferably, each of the first and second structural portions includes the same number of tabs. Each tongue of the first or second structural portion is arranged so as to be vis-à-vis a tongue of the other of the first or second structural portion when the first and second parts of the joint are assembled . The axial ends of each of these tongues are thus in contact with one another when the first and second parts of the joint are assembled.

In certain embodiments, the first part of the seal comprises at least a first attachment part fixed to a tongue of the first structural portion, and the second part of the seal comprises at least a second part of fastener fixed to a tongue of the second structural portion, the first and the second fastening part being configured to cooperate together so as to assemble the first part of the seal to the second part of the seal.

The first attachment part and the second attachment part are preferably fixed under the tongue of the first and second structural portion respectively, that is to say on a radially internal face of these structural portions when the joint sealing is mounted on a platform, itself mounted on a turbomachine fan. The fastener parts can be fixed by being attached to the tongues, for example by welding, or be molded or machined in a block, from the same material as the first and second structural portions.

The first and second attachment parts allow the first and second parts of the seal to be assembled and fixed, so that said first part and said second part of the seal are linked to one another. 'other. The first attachment part may for example be a female attachment part, and the second attachment part may be a part male attachment coming to be fixed, for example by clipping, on the female attachment part.

There can be as many parts of fasteners as there are tabs. More specifically, when each of the first and second structural portions has two tabs, a first tab of the first structural portion may have a first attachment portion, and a first tab of the second structural portion may include a second configured attachment portion to attach to the first attachment part. Likewise, a second tab of the first structural portion may include a first attachment portion, and a second tab of the second structural portion may include a second attachment portion configured to be assembled with the first attachment portion.

In certain embodiments, the assembly between the first attachment part and the second attachment part is reversible. This thus offers the possibility of easily separating the first and second parts of the seal, for maintenance or replacement of the latter.

The present disclosure also relates to an inter-blade platform comprising a seal according to any one of the preceding embodiments, the first part of the seal being fixed to the second part of the seal.

In certain embodiments, the platform comprises a box delimited by a vein wall to define an air flow vein, the box comprising at least one lateral passage configured to receive a tongue of a first and / or of a second structural portion of the seal.

The box keeps the vein wall in position, and also limits its deformation under the effect of centrifugal forces. The box also has a bottom surface that can bear on a blower disc. The passages existing in the box are orifices arranged radially under the vein wall, preferably adjacent thereto, and the dimensions allow the passage of the tab (s) of the structural portions of the seal. The presence of these passages allows the assembly of the first and the second part of the seal, and makes possible the communication of the first and of the second part of the seal by means of the tongues, and thus the displacement of the seal extending on either side of the platform in a circumferential direction, radially under the vein wall.

The present disclosure also relates to a rotor comprising a disk at the periphery of which are mounted a plurality of blades and a plurality of inter-blade platforms according to any one of the preceding embodiments, each platform being disposed between each pair of blades. adjacent

The present description also relates to a turbomachine and in particular a turbojet engine comprising a rotor according to the previous embodiment.

Brief description of the drawings

• [Fig. 1] la figure 1 représente une vue schématique en coupe d'un turboréacteur selon l'invention,
• [Fig. 2] la figure 2 représente une vue schématique selon la direction II de la soufflante de la figure 1,
• [Fig. 3] la figure 3 représente une vue partielle d'une section d'une soufflante selon l'art antérieur,
• [Fig. 4A-4B] la figure 4A représente schématiquement une vue du dessous d'un joint d'étanchéité selon l'invention lorsque les première et deuxième parties du joint d'étanchéité sont jointes, et la figure 4B représente une vue du dessous d'un joint d'étanchéité selon l'invention lorsque les première et deuxième parties du joint d'étanchéité sont disjointes,
• [Fig. 5A-5C] la figure 5A représente une vue en perspective d'une première et d'une deuxième partie d'attache du joint d'étanchéité selon l'invention en position verrouillée, la figure 5B représente une vue en perspective d'une première et d'une deuxième partie d'attache du joint d'étanchéité selon l'invention en position déverrouillée, et la figure 5C représente une vue de face d'une première et d'une deuxième partie d'attache du joint d'étanchéité selon un autre exemple de l'invention en position verrouillée,
• [Fig. 6A-6B] la figure 6A représente une vue en perspective d'une plateforme selon l'invention, et la figure 6B représente une section latérale de la plateforme de la figure 6A selon un plan de coupe VIB-VIB,
• [Fig. 7] la figure 7 représente une vue en coupe suivant un plan parallèle à la direction circonférentielle de la plateforme selon l'invention.

The invention and its advantages will be better understood on reading the detailed description given below of various embodiments of the invention given by way of non-limiting examples. This description refers to the pages of attached figures, on which:

• [ Fig. 1 ] the figure 1 represents a schematic sectional view of a turbojet engine according to the invention,
• [ Fig. 2 ] the figure 2 represents a schematic view in direction II of the fan of the figure 1 ,
• [ Fig. 3 ] the figure 3 represents a partial view of a section of a blower according to the prior art,
• [ Fig. 4A-4B ] the figure 4A shows schematically a bottom view of a seal according to the invention when the first and second parts of the seal are joined, and the figure 4B represents a bottom view of a seal according to the invention when the first and second parts of the seal are separated,
• [ Fig. 5A-5C ] the figure 5A shows a perspective view of a first and a second attachment portion of the seal according to the invention in the locked position, the figure 5B shows a perspective view of a first and a second attachment portion of the seal according to the invention in the unlocked position, and the figure 5C represents a front view of a first and a second attachment part of the seal according to another example of the invention in the locked position,
• [ Fig. 6A-6B ] the figure 6A shows a perspective view of a platform according to the invention, and the figure 6B represents a side section of the platform of the figure 6A according to a VIB-VIB cutting plane,
• [ Fig. 7 ] the figure 7 shows a sectional view along a plane parallel to the circumferential direction of the platform according to the invention.

Description of the embodiments

In the present description, the term “axial” and its derivatives are defined with respect to the main direction of the joint and of the platform considered; the term "circumferential" and its derivatives are defined with respect to the direction which extends around the axial direction; the terms “radial”, “interior”, “exterior” and their derivatives are defined with respect to the main axis of the turbomachine, when the platform is mounted on a disc, itself mounted in the turbomachine; finally, the terms “above”, “below”, “lower”, “upper” and their derivatives are defined with respect to the radial direction with respect to the axis around which the turbomachine extends. Also, unless otherwise indicated, the same reference signs in different figures denote the same characteristics.

The figure 1 shows a schematic view in longitudinal section of a double-flow turbomachine 1 centered on the axis A around which the turbomachine extends. It comprises, from upstream to downstream: a blower 2, a low pressure compressor 3, a high pressure compressor 4, a combustion chamber 5, a high pressure turbine 6, and a low pressure turbine 7.

The figure 2 shows a schematic view of blower 2 of the figure 1 according to direction II. The blower 2 comprises a blower disc 40 in which a plurality of grooves 42 are formed at its outer periphery. These grooves 42 are rectilinear and extend axially from upstream to downstream along the disc 40. They are also regularly distributed all around the axis A of the disc 40. In this way, each groove 42 defines with its neighbor a tooth 44 which also extends axially from upstream to downstream along the disc 40. Equivalently, a groove 42 is delimited by two circumferentially adjacent teeth 44.

The fan 2 further comprises a plurality of blades 20 of curvilinear profile (only four blades 20 have been shown on the figure 2 ). Each blade 20 has a foot 20a which is mounted in a respective groove 42 of the fan disc 40. To this end, the foot 20a of a blade 20 may have a shape of a fir tree or a dovetail adapted to the geometry of the grooves 42, each foot 20a having a shape at least partially complementary to the shape of the groove 42 in which it is mounted.

Finally, the fan 2 comprises a plurality of attached platforms 30, each platform 30 being mounted in the interval which extends circumferentially between two adjacent fan blades 20, in the vicinity of the feet 20a thereof, in order to delimit, from the on the inside, an annular air intake duct in the blower 2, the duct being delimited on the outside by a fan casing (not shown).

As illustrated in the figure 3 , each edge, or circumferential end 32a, 32b, of each platform 30, respectively opposite the side of the lower surface 22a and the side of the upper surface 22b of a blade 20, is respectively equipped with a joint 100 and a joint 100 'according to the prior art, extending along said circumferential ends 32a, 32b in the axial direction. In this example, the seal 100 is configured to cooperate with the blade 20 on the side of the lower surface 22a while the seal 100 'is configured to cooperate with the blade 20 on the side of the upper surface 22b. A displacement of a first dawn 20 (the one on the left on the figure 3 ) in the circumferential direction Y tends to exert a pressure on the seal 100. Conversely, a displacement of a second blade 20 (the one on the right on the figure 3 ) in the same circumferential direction Y tends to move this blade 20 away from the seal 100 '(arrow on the figure 3 ).

The Figures 4A and 4B schematically represent a bottom view of a seal 10 according to the invention when the first and second parts of the seal are joined ( figure 4A ) and disjoint ( figure 4B ). The X axis represents the axial direction, and the Y axis represents the circumferential direction. When the seal 10 is mounted on a platform 30, itself mounted on a fan disk, the axis X is substantially parallel to the central axis A of the turbojet engine. In these figures, the circumferential ends of the seal 10 have a rectilinear shape in the axial direction X. This illustration is schematic, the seal 10 not being limited to this shape. On the contrary, the circumferential ends of the seal 10 may have a curved shape, so as to match the shape of the profile of the blade with which they are in contact when the seal 10 is mounted on a fan platform. Furthermore, the face of the seal 10 illustrated on the Figures 4A and 4B , in this view from below, is the face directed towards the axis of the fan when the seal 10 is mounted on a fan platform, in other words, the radially internal face of the seal 10.

The seal 10 comprises a first part 10a and a second part 10b, distinct from the first part 10a. The first part 10a comprises a first contact portion 12a, and a first structural portion 14a, fixed to each other, for example by gluing. Similarly, the second part 10b comprises a second contact portion 12b, and a second structural portion 14b, fixed to one another, for example by gluing. The contact portions 12a, 12b each comprise an elastomeric material, and are designed to be in contact, respectively, with the circumferential end 32a of the platform 30 and a blade adjacent to said circumferential end 32a, and the circumferential end 32b of the platform 30 and a blade adjacent to said circumferential end 32b.

The structural portions 14a, 14b each comprise a metallic material, for example an aluminum alloy, and may also comprise a carbon composite. Alternatively, the structural portions may comprise an elastomer having a submerged portion of aluminum alloy, or be entirely metallic, of aluminum or titanium alloy. In the example illustrated on Figures 4A and 4B , the first structural portion 14a comprises three tabs 140a, and the second structural portion 14b also comprises three tabs 140b. The circumferential ends 141a of the tongues 140a of the first structural portion 14a are configured to come into contact with the circumferential ends 141b of the tongues 140b of the second structural portion 14b, when the first and the second part 10a, 10b of the joint are assembled. According to this embodiment, the tongues 140a of the first structural portion 14a are shorter, in the circumferential direction, than the tongues 140b of the second structural portion 14b. However, the seal 10 is not limited to this structure. The tongues 140a, 140b can for example have an equal length. Similarly, the dimension of the tongues in the axial direction X is given by way of illustration on the Figures 4A, 4B , and may vary depending on the structure of the platform 30 on which the seal 10 is mounted. The number of these tabs can also vary, and can be less than or greater than three for each structural portion 14a, 14b, each tab 140a of the first structural portion 14a having to be opposite, in the circumferential direction Y, with a tongue 140b of the second structural portion 14b.

Furthermore, the seal 10 comprises a first attachment part 16a fixed to a tongue 140a of the first structural portion 14a, and a second attachment part 16b, fixed to a tongue 140b of the second structural portion 14b. These attachment parts 16a, 16b are fixed to a radially internal face of the seal 10, when the latter is mounted on a fan platform 30. On the figure 4A , a single pair of fastener parts 16a, 16b is illustrated. However, a first attachment part 16a can be provided on two, or on each tongue 140a of the first structural portion 14a. Of even, a second attachment part 16b can be provided on two, or on each tongue 140b of the second structural portion 14b.

The Figures 5A and 5B show a perspective view of a first and a second attachment part 16a, 16b of the seal 10 according to the invention, when these are in the locked position and in the unlocked position respectively. The first attachment part 16a comprises a first fixing portion 161a, fixed to the tongue 140a, for example by welding, and a first pin part 162a, comprising a first branch 162a1 extending in the circumferential direction from the portion fixing 161a, and a second branch 162a2 extending from the circumferential end of the first branch 162a1 towards the fixing portion 161a. The second attachment part 16b comprises a second fixing portion 161b, fixed to the tongue 140b, for example by welding, and a second pin portion 162b, comprising a first branch 162b1 extending in the circumferential direction from the portion fixing 161b, and a hook 162b2, extending from the first branch 162b1 so that the end of the hook 162b2 is directed towards the fixing portion 161b.

When the first and the second part 10a, 10b of the joint 10 are brought together, the second branch 162a2 of the first pin part 162a slides along the hook 162b2 of the second pin part 162b, by deforming elastically so as to approach the first branch 162a1. When the first and second parts 10a, 10b of the seal 10 are brought closer to one another, so that the circumferential ends 141a and 141b of the tongues 140a, 140b come into abutment with each other according to a contact surface 141, the end of the second branch 162a2 of the first pin part 162a passes over the hook end 162b2 again moving away from the first branch 162a1, when the first part d pin 162a regains its original shape. The first and second attachment portions 16a, 16b are thus in the locked position, and the first and second portions 10a, 10b are then joined to each other. It is also possible to separate the two parts 10a, 10b from each other, by exerting a force on the first part 10a in the axial direction X, so as to release the second branch 162a2 from the hook 162b2.

The figure 5C shows a perspective view of a first and a second attachment portion 17a, 17b of the seal 10 of the invention according to an alternative example, when these are in the locked position. The first attachment part 17a comprises a first fixing portion 171a, fixed to the tongue 140a, for example by welding, and a first notched part 172a extending in the circumferential direction from the fixing portion 171a, the first notched part 172a comprising a first step 172a1 extending perpendicular to the circumferential direction. The second attachment part 17b comprises a second fixing portion 171b, fixed to the tongue 140b, for example by welding, and a second notched part 172b extending in the circumferential direction from the fixing portion 171b, the second notched part 172b comprising a second step 172b1 extending perpendicular to the circumferential direction.

When the first and second parts 10a, 10b of the joint 10 are brought together, an inclined wall of the first notched part 172a slides along an inclined wall of the second notched part 172b, deforming both elastically. When the first and second parts 10a, 10b of the seal 10 are brought closer to one another, so that the circumferential ends 141a and 141b of the tongues 140a, 140b come into abutment with each other according to the contact surface 141, the first step 172a1 passes over the second step 172b1, so that the first and second notched parts are found hooked to each other. The first and second attachment portions 17a, 17b are thus in the locked position, and the first and second portions 10a, 10b are then joined to one another.

The figure 6A shows a perspective view from above of a platform 30 according to the invention, on which is mounted a seal 10, and the figure 6B represents a side section of the platform of the figure 6A according to a VIB-VIB cutting plane. The platform 30 comprises a box 32 making it possible to keep the vein wall 34 in position, and also limit its deformation under the effect of centrifugal forces. The box 32 also has a bottom surface 36 which can bear on a tooth 44 of the disc 40 of the fan. The box 32 has lateral passages 38 in its radially outer part, radially under the vein wall 34. Each structural portion 14a, 14b has as many tabs 140a, 140b as there are passages 38. When the joint d seal 10 is mounted on the platform 30, the first part 10a is inserted radially under the vein wall 34 from a circumferential end 32a of the platform 30, passing the tongues 140a through the passages 38. Similarly, the second part 10b is inserted radially under the vein wall 34 from the other circumferential end 32b of the platform 30, passing the tongues 140b through the passages 38, until the lateral ends 141a, 141b come into contact with each other the others according to the contact surface 141, and that the first and second attachment parts 16a, 16b are in the locked position.

The figure 7 shows a sectional view along a plane parallel to the circumferential direction of the platform 30, at a passage 38. According to this embodiment, the contact portions 12a, 12b have a rectangular section. However, this shape is not limiting, other shapes allowing the contact portions 12a, 12b to slide partially radially under the wall of the vein 34, are conceivable. The contact portions may for example have a flared shape towards the contact area with the blade, or a substantially T-shape, as illustrated in the figure 3 . When the blades 20 (not shown in the figure 7 ) move in the direction of the arrows on the figure 7 , a blade 20 exerts a force on the contact portion 12a, and consequently on the structural portion 14a. This force is transmitted to the structural portion 14b via the contact surface 141 at the ends of the tongues. A displacement of the assembly of the seal 10 is thus generated, the seal 10 sliding under the vein wall 34 passing through the passages 38. The displacement resulting from the contact portion 12b, in the direction of the arrow on the figure 7 thus compensates for the movement of the dawn 20 in the same direction, and thus to retain the sealing function of the contact portion 12b, between the circumferential end 32b of the platform and the blade 20.

Although the present invention has been described with reference to specific exemplary embodiments, it is obvious 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 illustrated / mentioned embodiments can be combined in additional embodiments. Therefore, the description and the drawings should be considered in an illustrative rather than restrictive sense.

Claims (10)

Seal (10) for an inter-blade platform intended to extend circumferentially around an axis and to be mounted between two axial ends of the inter-blade platform (30), the seal (10) comprising at least a first part (10a) configured to be in contact with a first blade (20) circumferentially adjacent to a first circumferential end (32a) of the platform (30), and at least a second part (10b) configured to be in contact with a second vane (20) circumferentially adjacent to a second circumferential end (32b) of the platform (30), the first part (10a) and the second part (10b) of the seal (10) being configured to be fixed to each other so that a displacement in a circumferential direction of one of the first or second part (10a, 10b) of the seal (10) causes a displacement of the other from the first or second part (10a, 10b) of the seal (10) in the same direction, when the first part (10a) and the second part (10b) of the seal (10) are fixed to each other. A seal (10) according to claim 1, wherein the first part (10a) of the seal (10b) comprises a first contact portion (12a) made of an elastomeric material, the first contact portion (12a) being configured to be in contact with the first circumferential end (32a) of the platform (30) and the first blade (20) circumferentially adjacent to the first circumferential end (32a) of the platform (30), and the second part (10b ) of the seal (10) comprises a second contact portion (12b) made of an elastomeric material, the second contact portion (12b) being configured to be in contact with the second circumferential end (32b) of the platform (30 ) and the second blade (20) circumferentially adjacent to the second circumferential end (32b) of the platform (30). Seal (10) according to claim 1 or 2, wherein the first part (10a) of the seal (10) comprises a first structural portion (14a), and the second part (10b) of the seal sealing (10) comprises a second structural portion (14b), the first structural portion (14a) and the second structural portion (14b) being configured to join together. A seal (10) according to claim 3, wherein each of the first and second structural portions (14a, 14b) comprises a metallic material. Seal (10) according to claim 3 or 4, in which at least one of the first and of the second structural portion (14a, 14b) comprises at least one tongue (140a, 140b) extending circumferentially, a circumferential end (141a, 141b) of said tongue (140a, 140b) being configured to come into contact with the other of the first and of the second structural portion (14a, 14b). Seal (10) according to claim 5, wherein the first part of the seal (10a) comprises at least a first attachment part (16a) fixed to a tongue (140a) of the first structural portion ( 14a), and the second part (10b) of the seal (10) comprises at least a second attachment part (16b) fixed to a tongue (140b) of the second structural portion (14b), the first and the second attachment part (16a, 16b) being configured to cooperate together so as to assemble the first part (10a) of the seal (10) to the second part (10b) of the seal (10). Inter-blade platform (30) comprising a seal (10) according to any one of the preceding claims, the first part (10a) of the seal (10) being fixed to the second part (10b) of the seal sealing (10). Platform (30) according to claim 7, comprising a box (32) delimited by a vein wall (34) to define an air flow vein, the box (32) comprising at least one configured lateral passage (38) to receive a tongue (140a, 140b) of a first and / or a second structural portion (14a, 14b) of the seal (10). Rotor comprising a disc (40) at the periphery of which are mounted a plurality of blades (20) and a plurality of platforms (30) inter-blade according to claim 7 or 8, each platform (30) being disposed between each pair of 'circumferentially adjacent vanes (20). Turbomachine (1) comprising a rotor according to claim 9.

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