Sealing assembly and associated turbomachine

Abstract

A sealing assembly for a turbomachine (100), comprising: a first and a second ring sector (70) extending circumferentially end-to-end around an axis (X) and each having a first and a second circumferential end face (70a) arranged circumferentially opposite each other, the circumferential end faces (70a) comprising respectively a first and a second groove (75; 75b) arranged circumferentially opposite each other so as to form a housing (76; 76b) comprising a through axial opening (77a), a sealing tab (8) mounted in the housing (76;76b) to achieve a seal between the two ring sectors (70), the sealing tab (8) comprising a first arm (81) formed in a first material and a second arm (82) connected to the first arm (81) and formed in a second material, the first material having a coefficient of thermal expansion different from the coefficient of thermal expansion of the second material. Figure for the abbreviation: Fig. 4;

Description

Title of the invention: Sealing assembly and associated turbomachine technical field

[0001] The present invention relates to the field of turbines for turbomachinery. It relates more particularly to a turbine stage for a turbomachine, such as a turbojet or an aircraft turboprop.

[0002] In particular, the present invention relates to a sealing assembly for a turbomachine turbine, and an associated turbomachine. STATE OF THE ART

[0003] A turbomachine, in particular a twin-body turbomachine, conventionally comprises, from upstream to downstream, according to the direction of flow circulation in the turbomachine, a blower, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine and a low-pressure turbine.

[0004] The low-pressure turbine allows the power generated in the combustion chamber to be exploited and released and typically comprises several stages, each with a ring of fixed blades carried by an external casing and a ring of movable blades mounted to rotate around an axis of rotation of the turbomachine.

[0005] With reference to [Fig. 1], the moving blades rotate within an annular or sectored ring structure 6 attached to the outer casing 4. This ring 6 is formed of several ring sectors 60 to compensate for expansion problems of the assembly when subjected to high temperatures. These ring sectors 60, which extend circumferentially in an arc, are arranged circumferentially end to end. To ensure the sealing of a stream defined by an outer end of the moving blades 6 and to limit leakage of hot gas to the outside of the stream, the circumferentially end-to-end arranged sectors have grooves 65 on their circumferentially facing faces, in which one or more sealing tabs 64 are disposed.

[0006] More specifically, the sealing tab 64 is flat and mounted partly in a groove 65 of a circumferential end face of a ring sector 60 and partly in a groove 65 of a circumferential end face of a circumferentially adjacent ring sector 60, located opposite, the two grooves 65 cooperating to form a housing 66. The sealing tab 64 thus straddles the inter-sector space between two circumferentially adjacent ring sectors 60 and limits the passage of gases between the two ring sectors 60.

[0007] As illustrated in [Fig.1], each ring sector 60 can include several grooves 65 so as to form several housings 66 each receiving a sealing tab 64. For example, each ring sector can include a first groove 65a and a second groove 65b, the first groove 65a of a ring sector 60 cooperating with a corresponding first groove 65a of the circumferentially adjacent ring sector 60 to form a first housing 66a and the second groove 65b of a ring sector 60 cooperating with a corresponding second groove 65b of the circumferentially adjacent ring sector 60 to form a second housing 66b.

[0008] Each of the grooves 65a, 65b can be located in strategically chosen areas of the ring sector 60 in order to maximize the gain in sealing after positioning the sealing tabs 64 in the corresponding housings 66a, 66b.

[0009] However, during the operation of the turbomachine, vibrations or stresses can cause downstream displacement of the sealing tab 64, which can then escape from the housing 66 in which it is mounted. Besides the loss of the escaped sealing tabs 64, this displacement can have significant consequences, particularly for the casing 4, which can be damaged due to contact with the sealing tabs 64. Furthermore, the escape of a sealing tab 64 generates a significant local thermal impact (estimated at a transient temperature increase of 65°C). Consequently, the service life of the numerous components in this area of ​​the turbine can be reduced due to the loss of one of these sealing tabs.

[0010] An escape of a sealing tab 64 from its housing 66 can also occur during maintenance of the turbomachine, during which the orientation of the turbomachine can, due to gravity, contribute to the loss of a sealing tab 64.

[0011] The loss of a sealing tab 64, in addition to the potential damage caused to the turbomachine, generates additional costs for dismantling and reassembling the turbomachine in order to recover the tab and replace it.

[0012] To avoid this, depending on the positioning of the grooves 65, the sealing tongue 64 received in the corresponding housing 66 can be retained in said housing 66 in different ways.

[0013] For example, the sealing tab 64 mounted in the first housing 66a can be retained by a stop formed by a downstream annular rail 40 which, after assembly of the sectored ring 6, is pressed against an opening in the housing 66a and thus prevents the sealing tab 64 from escaping through the opening. However, this solution is not entirely satisfactory because it restricts the positioning of the grooves 65 and therefore of the sealing tabs 64.

[0014] Alternatively, a sealing tab 64 can be inserted into a housing 66, and then the housing 66 can be closed once the sectored ring 6 has been assembled. However, this solution is complex in terms of assembly.

[0015] Moreover, these solutions are not applicable to all of the housings 66. For example, housing 65b has a downstream opening 67 not blocked by another part, which therefore does not prevent the sealing tongue from escaping. EXPOSED

[0016] One object of the present invention is to remedy the aforementioned disadvantages, by proposing a sealing assembly that maintains the seal between the different sectors of a ring while allowing easy assembly of the sealing tabs.

[0017] More specifically, the invention aims to provide a sealing assembly preventing the escape of a sealing tab.

[0018] To this end, according to a first aspect, a sealing assembly for a turbomachine is proposed, comprising: - a first ring sector and a second ring sector extending circumferentially end-to-end around a principal axis, the first ring sector having a first circumferential end face and the second ring sector having a second circumferential end face arranged circumferentially opposite the first circumferential end face, the first circumferential end face comprising a first groove and the second circumferential end face comprising a second groove, the first groove and the second groove being arranged circumferentially opposite each other so as to form a housing which has a through axial opening, - a sealing tab mounted in the housing so as to create a seal between the first ring sector and the second circumferentially adjacent ring sector,

[0019] the sealing tongue comprising a first radially external branch formed in a first material and a second radially internal branch, connected to the first branch and formed in a second material different from the first material, and the first material having a coefficient of thermal expansion different from the coefficient of thermal expansion of the second material.

[0020] Advantageously, the first material has a coefficient of thermal expansion greater than the coefficient of thermal expansion of the second material.

[0021] Preferably, the sealing tongue is mounted in an elastically deformed manner in the housing and cooperates with the housing so as to apply a force on the walls of the housing opposing the escape of the sealing tongue out of the housing.

[0022] Advantageously, the first branch comprises a main portion and an axial end portion which has a rim located axially opposite the axial opening, the axial end portion forming a non-flat angle with the main portion and being suitable to bear against and exert a pressure force against one of the walls of the housing.

[0023] Advantageously, the non-flat angle allows the axial end portion to exert a pressure force on said wall

[0024] Advantageously, the axial end portion is formed in the first material.

[0025] Advantageously, the axial end portion is welded to the main portion of the first branch or connected by a junction elbow to said main portion of the first branch.

[0026] In one embodiment, the second branch is connected to the first branch by at least one weld point.

[0027] Preferably, the weld point is axially distant from the axial end portion by at least half an axial length of the sealing tab.

[0028] Advantageously, each of the first branch and the second branch comprises a radially internal surface, a radially external surface, and a slice surface connecting the radially internal surface and the radially external surface, the radially internal surface of the first branch and the radially external surface of the second branch being at least partially superimposed, at least one weld point being disposed on the respective slice surfaces of the first branch and the second branch.

[0029] In one embodiment, each of the respective edge surfaces of the first and second branches comprises a portion of surface extending opposite a wall of the housing opposite the axial through opening, said portions of edge surfaces of the first branch and the second branch being aligned with each other, at least one weld point being disposed on said portions of edge surface.

[0030] In an alternative embodiment, each of the first branch and the second branch comprises a radially internal surface and a radially external surface, the first branch and the second branch being welded together in a weld zone extending between the radially internal surface of the first branch and the radially external surface of the second branch.

[0031] Advantageously, the sealing assembly includes a first weld point and a second weld point, each of the first weld point and the second weld point connecting the second branch to the first branch.

[0032] The present application also relates to a turbomachine comprising a turbine having a first turbine stage comprising a first distributor and a first vane wheel, and a second turbine stage comprising a second distributor, the turbine comprising a sealing assembly, as defined above, located axially between the first distributor and the second distributor, the sealing assembly extending circumferentially around the first vane wheel. DESCRIPTION OF THE FIGURES

[0033] Other features, objectives and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0034] Fig. 1 illustrates a detailed view of an interface between two ring sectors of a part of a low-pressure turbine according to the prior art;

[0035] Fig. 2 illustrates a cross-sectional view of a turbomachine according to one embodiment of the invention;

[0036] Figure 3 illustrates a cross-sectional view of a low-pressure turbine comprising a sealing assembly according to an embodiment of the invention; and

[0037] [Fig.4] illustrates a detailed cross-sectional view of an interface between two ring sectors of a part of the turbine of [Fig.3];

[0038] Fig. 5 illustrates a perspective view of a first example of the realization of a sealing tab according to the invention;

[0039] Figure 6 illustrates a perspective view of a second example of an embodiment of a sealing tab according to the invention;

[0040] Fig. 7 schematically illustrates the different stages of a process for assembling a stage of the turbine of Fig. 3.

[0041] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION

[0042] Elements which are identical to those of the turbine previously described in connection with [Fig.1] will not be described again and bear the same numerical references.

[0043] Figure 2 illustrates a turbomachine 100, in particular a twin-spool turbomachine, conventionally comprising, from upstream to downstream, along the direction of flow in the turbomachine represented by an axis X, a fan 110, a low pressure compressor 120, a high pressure compressor 130, a combustion chamber 140, a high pressure turbine 150 and a low pressure turbine 160.

[0044] By convention, in this application, the terms "upstream" and "downstream" are defined with respect to the direction of airflow in the turbomachine. Similarly, by convention in this application, the terms "inside" and "outside", "lower" and "upper", "internal" and "external" are defined radially with respect to the longitudinal axis X of the turbomachine.

[0045] As shown in [Fig.3], the turbomachine turbine 160 comprises several axially successive stages, each comprising an upstream distributor 2 and a downstream blade wheel 3.

[0046] Each distributor 2 comprises a radially internal annular platform 21 and a radially external annular platform 22 coaxial, between which extend radial or substantially radial vanes 23, regularly spaced circumferentially around the circumference of said platforms. The distributor 2 is mounted on an external housing 4 of the turbine 160.

[0047] As can be seen more clearly in [Fig. 4], which represents a detailed view of the part of [Fig. 2] outlined in dashed lines, the radially external annular platform 22 comprises at its upstream end, a radially external beak 221 and a radially internal beak 222, both extending upstream. These two rims extend on either side of an annular groove 223 open upstream AM.

[0048] The distributors 2 together form the fixed part of the motor called the "stator".

[0049] Each blade wheel 3 comprises a disc 30 carrying radial or substantially radial blades 31 on its outer periphery, the discs 30 of the different wheels being coaxially connected to each other and to a drive shaft by suitable means, so as to form the "rotor" of the turbine 160 (see [Fig.3]).

[0050] In [Fig.3], the turbine 160 shown differs from the turbine in [Fig.1] by its inter-sector ring sealing assembly.

[0051] This sealing assembly includes a sealing ring 7 located between a first distributor 2 and a second distributor 2, and forming an annular structure extending around the main longitudinal axis X.

[0052] When the turbine 160 is operating, the impeller 3 rotates inside the sealing ring 7. This ring 7, which extends around the impeller 3, is fixed to the outer casing 4 of the turbine 160. This ring 7 is formed of several circumferentially adjacent ring sectors 70 arranged end-to-end from upstream to downstream, each being fixed to the outer casing 4 of the turbine 160. Each ring sector 70 is therefore an arc of a circle whose two ends form a circumferential end face 70a extending in a plane passing through the axis X, said circumferential end face 70a being circumferentially adjacent to a face circumferential end 70a of a circumferentially adjacent ring sector 70. Ring sectors and housing#:

[0053] The ring sectors 70 each internally carry a block of abradable material 71. These blocks of abradable material are capable of cooperating by friction with annular scrapers 32 arranged at the radially external periphery of each rotor blade 31 (see [Fig.3]).

[0054] Each ring sector 70 has, on a radially external surface, a portion of an annular groove 72 that is radially open to the outside. When the different ring sectors 70 are assembled, these portions of the groove together define an annular groove 72, into which the downstream annular rail 40 of the outer housing 4 is engaged, so as to secure it to said housing 4.

[0055] The downstream annular rail 40 and the downstream ends of the various ring sectors 70 are held in a radial direction (i.e. from bottom to top and from top to bottom on the [Fig.4]) by the internal 222 and external 221 spoilers of the external platform 22.

[0056] Furthermore, each ring sector 70 includes at its upstream end, a circumferential member 73 with a C-shaped cross-section, which is axially engaged from downstream on an upstream annular rail 41 of the outer casing 4. Said circumferential member 73 is only partially represented on [Fig.4].

[0057] Each ring sector 70 has on its circumferential end face 70a at least one groove 75 cooperating with a groove 75 of the circumferential end face 70a of the circumferentially adjacent ring sector 70 to form a housing 76, said two grooves 75 being located circumferentially opposite each other when said two ring sectors 70 are mounted on the external housing 4. In particular in the example illustrated in [Fig.4], each ring sector 70 includes on its circumferential end face 70a a first groove 75a and a second groove 75b cooperating respectively with a first groove 75a of the circumferential end face of the circumferentially adjacent ring sector 70 to form a first housing 76a and with a second groove 75b of the circumferential end face of the circumferentially adjacent ring sector 70 to form a second housing 76b.

[0058] For example, the first housing 76a can extend along an external surface of the ring sector 70 opposite the external housing 4.

[0059] The second housing 76b in the example shown in [Fig. 4] opens downstream of the turbine 160. In other words, the second groove 75b of each of the ring sectors 70 opens downstream of the turbine 160, so that the second housing 76b has a downstream axial opening 77a that is through-hole, i.e., not blocked by another part. The second housing 76b, and therefore the second grooves 75b, are made in the downstream part of their respective ring sector 70, and radially under the portion of the groove 72.

[0060] As can be seen in [Fig. 4], the second housing 76b comprises a radially external wall 77b, a radially internal wall 77c, and a bottom wall 77d connecting the radially external wall 77b and the radially internal wall 77c. The bottom 77d is axially opposed to the downstream opening 77a, which forms an opening of the second housing 76b. The bottom 77d extends substantially radially with respect to the longitudinal axis X, while the radially internal wall 77c and the radially external wall 77b extend longitudinally around the longitudinal axis X.

[0061] To ensure inter-sector sealing, the sealing assembly includes a sealing tab in each of the housings 76. For example, a sealing tab 64 is inserted into the first housing 76a. This housing is not open because it is blocked by another part, in this case by the downstream annular rail 40, which prevents the sealing tab 64 from escaping from the first housing 76a once the sealing assembly is mounted in the turbine 160. Sealing tab#:

[0062] In particular the sealing assembly includes, in the second housing 76b, a sealing tab 8 configured to be elastically deformed when the sealing tab is received in the second housing 76b, so as to apply on walls of the second housing 76b a force opposing the sealing tab 8 to escape out of the second housing 76b through the axial opening 77a.

[0063] More specifically, the sealing tab 8 comprises a first radially external arm 81 and a second radially internal arm 82. The first arm 81 is connected to the second arm 82. The second arm 82 extends radially inside and opposite the first arm 81.

[0064] The first branch 81 comprises a main portion 83 which extends axially between a first axial end 81a and a second axial end 81b. The first axial end 81a is opposite the bottom 77d of the second housing 76b.

[0065] As illustrated in Figures 5 and 6, the first branch 81 comprises a first radially external surface 81c, a first radially internal surface 81d, and a first edge surface 81e which connects said first radially internal 81d and external 81c surfaces. The first radially external surface 81c extends opposite the radially external wall 77b of the second housing 76b.

[0066] The first slice surface 81e forms the periphery of the first branch 81, that is to say, the first slice surface 81e comprises surface portions connecting the edges of the radially internal surfaces 81c and external surfaces 81d around their entire periphery. In particular, the first slice surface 81e comprises a portion of slice surface 85 forming the first axial end 81a of the first branch 81 and extending opposite the bottom 77d of the second housing 76b.

[0067] Similarly, the second branch 82 extends radially between a first axial end 82a and a second axial end 82b. The first axial end 82a is opposite the bottom 77d of the second housing 76b.

[0068] Furthermore, the second branch 82 comprises a second radially external surface 82c, a second radially internal surface 82d, and a second edge surface 82e which connects said second radially internal 82c and external 82d surfaces. The second radially internal surface 82d extends opposite the radially internal wall 77b of the second housing 76b.

[0069] The second slice surface 82e forms the perimeter of the second branch 82. In particular, the second slice surface 82e includes a portion of slice surface 85 forming the first axial end 82a of the second branch 82 and extending opposite the bottom 77d of the second housing 76b.

[0070] When the tongue 8 is at rest (i.e. when the tongue 8 is not subjected to elastic deformation), the first radially internal surface 81d of the first branch 81 and the second radially external surface 82c of the second branch 82 are at least partially superimposed and in contact with each other, and are preferably so over the axial length of the main portion 83.

[0071] The portions of slice surface 85 of the first slice surface 81e and of the second slice surface 82e forming the first axial extremities 81a, 82a are preferably aligned with each other in a radial direction.

[0072] The first branch 81 may include an axial end portion 84 extending from the second axial end 81b of the main portion 83. This axial end portion 84 forms a rim.

[0073] The axial end portion 84 forms a non-flat angle with the main portion 83 of the first branch 81 and extends from the second axial end 81b so as to move away from the second branch 82.

[0074] When the tab 8 is at rest, the angle formed between the axial end portion 84 and the main portion 83 of the first arm 81 is between 90° and 180° (exclusive). This angle can therefore take any value within the open interval between 90° and 180°, and preferably between 120° and 175°, even more preferably between 160° and 170°.

[0075] The axial end portion 84 includes a free end 86 opposite the main portion 83.

[0076] The second axial end 82b of the second branch 82 is located opposite the axial opening 77d and occupies a similar axial position, preferably identical to the axial position of the free end 86 of the axial end portion 84 of the first branch 81.

[0077] The axial end portion 84 of the first branch 81 and the second branch 82 are able to be brought together by elastic deformation, for example by pinching, to reduce the thickness of the sealing tongue 8.

[0078] The sealing tab 8 thus defines a radial spacing between the axial end portion 84 and the second arm 82, which is progressive from the second axial end 81b of the main portion 83 to the free end 86 of the axial end portion 84. The radial spacing is understood to be the distance in a radial plane between a point on the axial end portion 84 and an opposite point on the second arm 82. The radial spacing at rest is understood to be said radial spacing when the sealing tab 8 is not elastically deformed, that is, for example, when it is outside the second housing 76b.

[0079] The radial spacing at rest (i.e. when the sealing tab 8 is out of the second housing 76b) between the axial end portion 84 and the second branch 82 is greater, at the level of the free end 86 of the axial end portion 84, than the radial dimensions (between the radially external walls 77b and internal walls 77c) of the second housing 76b receiving said sealing tab 8. Thus, the sealing tab 8 must be elastically deformed to bring the axial end portion 84 and the second branch 82 closer together, for example by pinching, in order to be able to be inserted into the second housing 76b through the open downstream opening 77a.

[0080] When the sealing tongue 8 is housed in the second housing 76b, the radial dimensions of the second housing 76b being less than the thickness of the sealing tongue 8, the sealing tongue 8 is elastically deformed by the external radial and internal walls 77b and 77c of the second housing 76b, which prevent the axial end portion 84 and the second arm 82 from regaining their radial spacing at rest. The said walls 77b and 77c compress the sealing tongue 8 so that the axial end portion 84 and the second branch 82 are in contact with the walls 77b and 77c, and exert on them a force, more precisely a radial force, opposing the sliding of the sealing tongue 8 in the second housing 76c, and therefore opposing the escape of the sealing tongue 8 from the second housing 76c.

[0081] Thus, the elastic deformation of the sealing tongue 8 therefore opposes a migration of the sealing tongue 8 out of the second housing 76b.

[0082] The first branch 81 and the second branch 82 are connected by at least one weld point 87.

[0083] Fig. 5 illustrates a first example of an embodiment of the sealing tongue 8 in which the first branch 81 and the second branch 82 are connected to each other by at least one weld point 87 disposed on the respective edge surfaces 81e and 82e of the first and second branches 81 and 82.

[0084] More specifically, at least one weld point 87 is disposed on the surface portions 85 of the slice surfaces 81e and 82e, at their point of contact. Possibly, in order to reinforce the assembly of the first and second branches 81 and 82, the sealing tab 8 may include two (or more) weld points 87 on the surface portions 85 of the slice surfaces 81e and 82e, at their junction.

[0085] Figure 6 illustrates a second embodiment of the sealing tab 8 in which the first arm 81 and the second arm 82 are joined together by at least one weld point 87 located in a weld zone extending between the first radially internal surface 81d of the first arm 81 and the second radially external surface 82c of the second arm 82. Optionally, to reinforce the connection between the first and second arms 81 and 82, the sealing tab 8 may include two (or more) weld points 87 in said weld zone. These weld points 87 may be distributed axially to strengthen the sealing tab 8. The weld points 87 are located to more precisely join the main portion 83 of the first arm 81 to the second arm 82. In the example shown in Figure 6, two weld points 87 are formed.

[0086] This second embodiment is in particular easier to implement than the first example illustrated in [Fig.5].

[0087] The welding is preferably spot welding, but this is not limiting.

[0088] Welding is for example electric arc welding, although any other suitable type of welding may be used.

[0089] Connecting the first branch 81 and the second branch 82 by welding allows different materials to be used to make the first branch 81 and the second branch 82.

[0090] In particular, the first branch 81, and more specifically at least its main portion 83, is made of a first material having a first coefficient of thermal expansion, and the second branch 82 is made of a second material having a second coefficient of thermal expansion. Preferably, the first coefficient of thermal expansion is greater than the second coefficient of thermal expansion, so that the first branch 81 expands at a lower temperature and / or more significantly at the same temperature than the second branch 82. In this way, the first branch 81 expands during the operation of the turbomachine at a lower temperature and / or expands more significantly. For the same temperature, the elongation of the first arm 81, reflecting its expansion, increases the force exerted by the axial end portion 84 and the second arm 82 on the walls 77b and 77c of the second housing 76b. Thus, the higher the temperature, the greater the clamping force exerted by the tab 8 on the walls 77b and 77c. The retention of the sealing tab 8 in the second housing 76b is therefore improved.

[0091] For example, when the radial width between the radially external walls 77b and internal walls 77c of the second housing 76b is about 0.6 millimeters, the first branch 81 and the second branch 82 can be chosen with a radial thickness (defined between the radially internal and external surfaces 81d and 81c of the first branch 81 on the one hand and 82d and 82c of the second branch 82 on the other hand) of 0.15 to 0.3 millimeters.

[0092] In addition, welding the two branches 81 and 82 makes it easier to machine the sealing tab 8 than, for example, by bending a single sheet to form said two branches 81 and 82.

[0093] In order to promote the increase of the force exerted on the walls 77b and 77c of the second housing 76b due to the expansion of the first branch 81 as well as the pinching of the sealing tab 8 without risk of breakage of the weld, at least one weld point 87 is preferably axially distant from the axial end portion 84 by at least one third, advantageously half the axial length of the sealing tab 8. In this way, the welds are located axially opposite the pinching zone, which promotes the strength of the sealing tab 8 and limits the force exerted by the weld tending to limit the expansion of the first branch 81.

[0094] Preferably, the first branch 81, and therefore preferably the main portion 83 and the axial end portion 84, can be made of a nickel-based superalloy with, for example, a coefficient of thermal expansion of approximately 1.22 x 10⁵ °C⁻¹ and the second branch 82 can be made of a titanium alloy with, for example, a coefficient of thermal expansion of approximately 8.6 x 10⁶ °C⁻¹).

[0095] Other advantages of choosing different materials for the first branch 81 and the second branch 82 can be cited, such as choosing a stiffer material for the second branch 82, in order to promote the strength of the sealing tab 8 and limit its lifting while allowing for greater flexibility in the first branch 81. It is also possible to choose an insulating material for the second branch 82, in order to limit heat exchange outside of the vein and / or a less expensive material for the first branch to fulfill the holding function in the second housing 76b.

[0096] The axial end portion 84 can be connected by welding or by a connecting elbow to the main portion 83 of the first branch 81. Preferably, the axial end portion 84 includes one or more weld points 88, as schematically illustrated in [Fig. 4]. Preferably, the welding of the axial end portion 84 to the first branch 81 can be carried out by spot welding on the second axial end 81b of the main portion 83.

[0097] The axial end portion 84, when connected to the main portion 83 by welding, is preferably formed from the same material as the main portion 83 in order to increase the force exerted by the holding force of the sealing tab 8 in the second housing 76b when the temperature is sufficient to cause the first material to expand. The axial end portion 84 may alternatively be made from the same material as the main portion 83 or from a different material. Sealing tab mounting procedure#:

[0098] Fig. 7 illustrates the different steps of a method for mounting the sealing tab 8 in the second housing 76b.

[0099] In a first step El, Sectorized panel 7, in other words the annular structure, is mounted by assembling at least one first ring sector 70 and a second ring sector 70 circumferentially adjacent.

[0100] In a second step E2, the sealing tab 8 is pinched so as to be elastically deformed to bring the axial end portion 84 and the second branch 82 closer together, so as to reduce the thickness of said sealing tab 8.

[0101] In a third step E3, the sealing tab 8, the axial end portion 84 and the second arm 82 of which are pinched, is mounted by insertion into the second housing 76b which is intended to receive it.

[0102] In a fourth step E4, the pinch is released. The compression of the sealing tab 8 is then completed, and the first branch 81 and the second branch 82 move apart from each other to exert on the radial walls 77b and 77c of the housing 76b a force opposing the escape of the sealing tab 8 from its housing.

Claims

Demands

1. A sealing assembly for a turbomachine (100), comprising: - a first ring sector (70) and a second ring sector (70) extending circumferentially end-to-end about a principal axis (X), the first ring sector (70) having a first circumferential end face (70a) and the second ring sector (70) having a second circumferential end face (70a) arranged circumferentially opposite the first circumferential end face (70a), the first circumferential end face (70a) having a first groove (75; 75b) and the second circumferential end face (70a) having a second groove (75; 75b), the first groove and the second groove (75; 75b) being arranged circumferentially opposite each other so as to form a housing (76;76b) which has an axial through opening (77a), - a sealing tab (8) mounted in the housing (76; 76b) so as to achieve a seal between the first ring sector (70) and the second ring sector (70) circumferentially adjacent, the sealing tab (8) comprising a first radially external branch (81) formed in a first material and a second radially internal branch (82), connected to the first branch (81) and formed in a second material different from the first material, and the first material having a coefficient of thermal expansion different from the coefficient of thermal expansion of the second material.;

2. Sealing assembly according to claim 1, wherein the first material has a coefficient of thermal expansion greater than the coefficient of thermal expansion of the second material.

3. A sealing assembly according to claim 1 or 2, wherein the sealing tab (8) is mounted in an elastically deformed manner within the housing (76; 76b) and cooperates with the housing (76; 76b) so as to apply pressure to the walls of the housing (77; 77b; 77c) an effort opposing the escape of the sealing tab (8) from the housing (76; 76b).

4. Sealing assembly according to claim 3, wherein the first arm (81) comprises a main portion (83) and an axial end portion (84) which has a rim located axially opposite the axial opening (77a), the axial end portion (84) forming a non-flat angle with the main portion (83) and being suitable for bearing against and exerting a pressure force against one of the walls of the housing (77b).

5. Sealing assembly according to claim 4, wherein the axial end portion (84) is formed in the first material.

6. Sealing assembly according to any one of claims 4 and 5, wherein the axial end portion (84) is welded to the main portion (83) of the first branch (81) or connected by a joining elbow to said main portion (83) of the first branch (81).

7. Sealing assembly according to any one of claims 1 to 6, wherein the second arm (82) is connected to the first arm (81) by at least one weld point (87).

8. Sealing assembly according to any one of claims 4 to 6 in combination with claim 7, wherein the weld point (87) is axially distant from the axial end portion (84) by at least half an axial length of the sealing tab (8).

9. Sealing assembly according to any one of claims 7 or 8, wherein each of the first branch (81) and the second branch (82) comprises a radially internal surface (81d; 82d), a radially external surface (81c; 82c), and a slice surface (81e; 82e) connecting the radially internal surface and the radially external surface, the radially internal surface (81d) of the first branch (81) and the radially external surface (82c) of the second branch (82) being at least partially superimposed, at least one weld point (87) being disposed on the respective slice surfaces (81e; 82e) of the first branch (81) and the second branch (82).

10. Sealing assembly according to claim 9, wherein each of the respective edge surfaces (81e; 82e) of the first and second branches comprises a portion of edge surface (85) extending opposite a wall (77d) of the housing opposite to the axial through opening (77a), said portions of slice surfaces (85) of the first branch and of the second branch (81; 82) being aligned with each other, at least one weld point (87) being disposed on said portions of slice surface (85).

11. Sealing assembly according to claim 7, wherein each of the first branch (81) and the second branch (82) comprises a radially internal surface (81d; 82d) and a radially external surface (81c; 82c), the first branch (81) and the second branch (82) being welded together in a weld zone extending between the radially internal surface of the first branch (81d) and the radially external surface of the second branch (82c).

12. Sealing assembly according to any one of claims 7 to 11, comprising a first weld point (87) and a second weld point (87), each of the first weld point and the second weld point connecting the second branch (82) to the first branch (81).

13. Turbomachine (100) comprising a turbine (160) having a first turbine stage comprising a first distributor (2) and a first vane wheel (3), and a second turbine stage comprising a second distributor (2), the turbine (160) comprising a sealing assembly according to any one of claims 1 to 12 situated axially between the first distributor (2) and the second distributor (2), the sealing assembly extending circumferentially around the first vane wheel (3).

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