Multi-axial shim plate for turbomachine rotor, rotor and turbomachine assembly

Abstract

MULTI-AXIAL WEDGE PLATE FOR TURBOMACHINE ROTOR, ASSOCIATED ROTOR AND TURBOMACHINE ASSEMBLY One aspect of the invention relates to a multi-axial wedge plate P for axially retaining blades 3 in recesses 20 of a turbomachine disk 2 centered on an axis X, the plate comprising a first axial retaining wall 4, which is configured to be mounted against a radial surface 24 of the disk 2, the first axial retaining wall 4 comprising a radially external peripheral edge 4e with respect to the axis X.The plate further comprises at least two wedges 5, each comprising a main portion 51 extending longitudinally from the radially external peripheral edge 4e, configured to be mounted in a recess 20 of the disk 2, and a second axial retaining wall 53 configured to cooperate with a blade root and extending, opposite each main portion 51, to the opposite longitudinal end of the first axial retaining wall. Figure to be published with the abbreviation: Figure 3A.

Description

Title of the invention: MULTI-AXIAL WEDGE PLATE FOR TURBOMACHINE ROTOR, ASSOCIATED ROTOR AND TURBOMACHINE ASSEMBLY TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of turbomachinery such as turboprops or turbojets. More particularly, the invention relates to a shim for a turbomachine rotor, as well as a rotor assembly equipping such a turbomachine. It aims, for example, at the axial locking of turbine or fan blades in their housing located on a rotor disk. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] A turbomachine rotor, for example a rotor implemented in a low-pressure turbine extending around a longitudinal axis and conventionally comprising one or more rotor disks carrying on their outer periphery a plurality of movable blades mounted in cells of the disk.

[0003] The movable blades have a radially internal portion, or blade root, extended by a blade. Each movable blade is housed at its root in one of the recesses of the disk that open onto the outer peripheral surface of the rotor disk. The positioning of the blade roots in the recesses of the rotor disks is achieved by translation along a recess direction generally inclined at a few degrees relative to the axis of the turbomachine.

[0004] To facilitate the mounting of the movable blades on the rotor discs, sufficient clearance must be provided to allow the blade roots to slide easily within the recesses. A relatively large amount of clearance therefore remains once the blade root is mounted in the recess, necessitating an axial retaining device to hold one or more blade roots, such as flanges mounted and wedged on each side of the blade and the disc, or axial wedges, each positioned in its corresponding recess to retain the blade in the recess along an axial direction.

[0005] Narrow axial spacers are used to allow maximum airflow through the gap between the blade root and the bottom of the recess in order to cool the blade root. Indeed, during rotor rotation, each blade root is subjected to high temperatures during turbomachine operation due to the blades being located in the low-pressure turbine's gas flow path, which is traversed by high-temperature gases. Since the recesses in the discs that receive the blade roots are directly exposed to these gases, it may be necessary to cool them. To avoid any damage to the discs, one known method is to draw a portion of the air flowing outside the low-pressure turbine's flow path and direct it, via a cooling circuit, to the rotor disc cells. This is achieved either through channels within the disc, as described in the applicant's FR3054855, or through a fresh airflow channel formed between a cylindrical flange mounted axially against the blade root and the disc. This channel delivers air between the blade root and the bottom of the disc cell. The flange can also be used to hold the blade root in the opposite axial direction.

[0006] Fig. 1A represents the case of a narrow axial wedge 1 comprising a central part 10 housed in a cavity 20 of a disk 2 between the bottom of the cavity 20 and a blade root 32 of a blade 3. Only one blade 3 is shown in this Fig. 1A; it comprises a blade 30, a platform 31 extending from the blade 30 and the blade root 32 extending from the platform 31 housed in the cavity 20 between two teeth 21 of the disk 2. The axial wedge 1 is further shown in Fig. 1B, which represents the axial wedge 1 in three dimensions.

[0007] The axial wedge 1 thus comprises a central portion 10 housed in and extending along the recess 20, and a first axial retaining tab 13 for the blade 3, extending from a first end of the central portion 13 outside the recess 20 and mounted against a radial surface of the blade root 32 to retain it axially. In this [Fig. 1A], a first radial face 23 of the disk 2 is shown, and the tab 13 can be seen. The axial wedge 1 further comprises a second axial retaining tab 12 mounted against a second radial surface (not visible) of the disk 2 and extending to one end of the main portion 13 opposite the first end.

[0008] However, the wedge 1 can become misaligned with respect to the x' direction of the cavity 20, as shown in Figures 2A and 2B, which schematically represent respectively an axial wedge 1 housed in a cavity 20 and extending longitudinally along the inclined x' direction of the cavity 20 with respect to the axis of rotation x, and an axial wedge 1 housed and, in the worst case, misaligned in the cavity 20 with respect to the inclined x' direction of the cavity 20. Here, the x' direction of the cavity 20 is at an angle with respect to the axis of rotation x. The x' direction and the axis of rotation x each extend in two parallel planes. As can be seen in [Fig.2A], the axial wedge 1 protrudes from the disk 2 only by its thickness e representing the second tab 12 against the radial surface of the disk 2. Of course the first tab 13 can also protrude from the disk 2 if the radial surface of the blade foot 3 is flush with a radial surface of the disk 2 opposite to that in butt.As can be seen in [Fig. 2B], each axial shim 1 comprises a width 11 measured perpendicular (radially) to the insertion direction x'. This is due, on the one hand, to the fact that the width 11 is less than the width 12. From the bottom of the corresponding cavity 20 housing the central part 10 opposite an end surface of the blade root 21, and on the other hand from the inclination of a few degrees between 0° and 30° of the insertion direction x' of each cavity 20 with respect to the axis of rotation x, each axial wedge 1 can pivot, here at an angle measured between the longitudinal direction x” of the wedge 1 and the insertion direction x' of the cavity 20. This pivoting results in an axial overshoot 13,14 of the wedge 1 relative to the disk 2 on each side, which can lead to a displacement of a distance 15 along the translational direction x' of the blade root 32. This displacement 15 of the blade root 32 and the wedge 1 can cause turbulence, reducing the efficiency of the turbine and potentially damaging the blade 3. and hold 1.

[0009] There is therefore a need to have axial shims of small width according to their direction of translation along the cavity. Summary of the invention

[0010] The invention offers a solution to the problems mentioned above, by proposing a multi-axial wedge plate, the plate is held angularly by the different wedges connected to each other by a wall.

[0011] One aspect of the invention relates to a multi-axial wedge plate for axially retaining blades in the recesses of a turbomachine disk centered on an axis, the plate comprising: • a first axial retaining wall, configured to abut against a radial surface of the disk, the first axial retaining wall comprising a peripheral edge radially external to the X-axis, • at least two wedges, each comprising: • a principal portion extending longitudinally from the radially external peripheral edge of the axial retaining wall, each principal portion being configured to be housed in a recess of the disc and • a second axial retaining wall, configured to cooperate with a mounted blade foot and disposed opposite each main portion at the opposite longitudinal end of the first axial retaining wall.

[0012] Thanks to the invention, the plate reduces or even prevents the pivoting of the shims in the recesses. Indeed, linking the shims to each other by the axial retaining wall maintains an angular distance between the different central portions. Furthermore, the axial retaining wall includes a surface that angularly overlaps the radial surface of the disc, which limits the rotation of the shims in their respective recesses. In addition, the longitudinal directions of two central portions ad underlying along the circumferential direction extend longitudinally parallel to each other, each in a plane parallel to the X axis, different from each other and equidistant from the X axis, thus allowing them to extend into two circumferentially adjacent alveoli of a disk.

[0013] In addition to the characteristics just mentioned in the preceding paragraph, the plate according to one aspect of the invention may have one or more complementary characteristics among those described in the following paragraphs, considered individually or according to all technically possible combinations.

[0014] According to an example, the first axial retaining wall extends radially with respect to the X axis and the second axial retaining wall extends radially with respect to the central portion.

[0015] According to one embodiment, the main portion extends longitudinally along a longitudinal direction inclined with respect to a line parallel to the X axis passing through the portion of the peripheral edge.

[0016] According to one embodiment, the axial retaining wall comprises a base and teeth which extend radially in projection from the base, radially with respect to the X axis, outwards forming notches between them, the external peripheral edge being formed by the edge of the teeth and notches, each main portion extending in forming a bend with respect to a tooth: this makes it possible to reduce the weight, improve the precision of the bending between the axial retaining wall and the wedge and thus increase its strength.

[0017] According to a variant of this embodiment, the outer peripheral edge of the axial retaining wall is rectangular or rounded. This simplifies manufacturing.

[0018] According to one embodiment, the base is a ring or a sector of a ring centered on the X axis.

[0019] According to one embodiment, the plate comprises several main portions regularly distributed around the X axis, each main portion being configured to be mounted in a recess of the disc:

[0020] According to one embodiment, the insert is formed from a sheet of metal that is cut and folded to form the various shims from the axial retaining wall. This allows for a simple insert to be manufactured.

[0021] Another aspect of the invention relates to a set • an X-axis disk, comprising: • a first and a second opposing radial surface, • teeth at the radially external periphery of the disc and • alveoli formed between each pair of circumferential teeth Closely adjacent, each alveolus comprising a base, the teeth, and the alveoli connecting each to the second radial wall, • a multi-axial wedge plate according to the first aspect of the invention, in which the axial retaining wall is mounted against the second axial wall and in that the main portion of each wedge is housed in a cavity all along the bottom of the cavity.

[0022] According to one embodiment, the assembly further comprises blades, each comprising a blade foot housed in a recess of the disc, each wedge comprising: • the main portion between the bottom of the corresponding recess and the corresponding blade foot, • the second axial retaining wall mounted against a radial surface of the blade foot, this reduces the weight of the plate while allowing air to circulate.

[0023] According to one embodiment, the cells are inclined between 0° and 30° with respect to a plane passing through the axis of rotation.

[0024] According to one embodiment, the assembly includes an air circuit opening into each cavity. This allows the blade root to be cooled. For example, a space in the fresh air circuit is formed on one side between each tooth forming the cavity and the central portion of each wedge, and on the other side between the bottom of the cavity and the teeth

[0025] Another aspect of the invention relates to a turbomachine comprising a turbomachine rotor assembly according to the previous aspect with or without a combination of the characteristics of the different embodiments.

[0026] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0027] The figures are presented for illustrative purposes only and are in no way limiting of the invention.

[0028] [Fig. 1 A] schematically represents a perspective view of an assembly comprising a disc, a blade foot and a wedge according to the prior art.

[0029] [Fig. IB] schematically represents a perspective view of the hold of the whole of [Fig.1A] according to the prior art.

[0030] [Fig.2A] schematically represents a top view of a wedge according to the prior art in a socket.

[0031] [Fig.2B] schematically represents a top view of the wedge of [Fig.2A] according to the prior art offset in the alveolus.

[0032] [Fig.3A] represents a perspective view of a multi-axial wedge plate according to a first example of a first embodiment.

[0033] [Fig.3B] represents a perspective view of an assembly comprising a disk shown without the teeth and notches and two plates of [Fig.3A] according to the first embodiment mounted on the disk.

[0034] [Fig.4] represents a perspective view of a multi-axial wedge plate according to a second example of the first embodiment.

[0035] [Fig.5A] represents a perspective view of a multi-axial wedge plate according to a second embodiment.

[0036] [Fig. 5B] shows a perspective view of an assembly comprising a disc shown without the teeth and notches and the multi-axial wedge plate of [Fig. 5A] according to the second embodiment, mounted on the disc. DETAILED DESCRIPTION

[0037] The figures are presented for illustrative purposes only and are in no way limiting of the invention.

[0038] [Fig.3A] shows a schematic perspective representation of a plate P with multi-axial wedges according to a first embodiment of the invention.

[0039] The plate P allows to axially maintain a plurality of blades, in this embodiment two blades in the pits of a turbomachine disk, in an axial direction.

[0040] The plate P comprises a first axial retaining wall 4, hereafter referred to as the axial retaining wall 4. This axial retaining wall 4 is perpendicular to an axis X corresponding to the axis of rotation of the disk 2 shown schematically in [Fig. 3B]. In other words, the axial retaining wall 4 extends radially with respect to the axis X. The disk 2 is therefore centered on the axis X and comprises teeth 21 and recesses 20, each formed between two circumferentially adjacent teeth 21, not shown in this [Fig. 3B], in order to show the shims 5 of two circumferentially adjacent plates P mounted on the disk 4, but are, for example, like those shown in [Fig. 1A]. Plate P further includes at least two wedges 5, of which only two are shown in this example, extending from the axial retaining wall 4. The wedges 5 are detailed later.

[0041] The axial retaining wall 4 comprises an external peripheral edge 4e with respect to the X-axis (i.e., along the X-axis), and an internal peripheral edge 4i, and in this example, two lateral edges 41, 4r. In this first example of this embodiment, the axial retaining wall 4 comprises a base 42 and teeth 43 extending longitudinally from the base 42 perpendicularly to the X-axis, outwards, forming a notch 44 between two circumferentially adjacent teeth 43. Thus, each tooth 43 extends radially outwards from the base 42, radially with respect to the X-axis. There are as many teeth 43 as there are shims 5, i.e., two teeth 43 in this example. Each notch 44 is therefore formed by an edge of the base 42 forming part of the external peripheral edge 4e and two edges of the teeth 43 also forming part of the external peripheral edge 4e.

[0042] The axial retaining wall 4 comprises a flat surface 423 configured to abut against the second radial surface 24 of the disk 2 shown schematically in this [Fig. 3B]. In this case, the flat surface 423 is a surface of the base 42 and the teeth 43.

[0043] In this first example of this embodiment, the outer peripheral edge 4e thus has a crenellated shape, in this case rectangular with the edge of the notch 44 rectangular and two teeth 43 each of rectangular shape.

[0044] According to another example shown in [Fig.4], identical to the example shown in Figures 3a and 3b, the outer peripheral edge 4e has a circular shape, in this case in the shape of an arc of a circle.

[0045] As previously mentioned, the plate P further comprises at least two wedges 5. Each wedge 5 comprises a main portion 51, shown in black in the first and second examples respectively in [Fig. 3A] and [Fig. 4], extending longitudinally from the axial retaining wall 4 in a plane parallel to the X-axis. The main portion 51 extends in particular from the outer peripheral edge 4e of the axial retaining wall 4, longitudinally along a longitudinal direction inclined X' between 0° and 30° with respect to a line d shown in [Fig. 3B], parallel to the X-axis and passing through the portion of the peripheral edge 4e. The inclined longitudinal direction X' corresponds to the direction of a recess 20 of the disc 2, as shown in Figures 2a and 2b.

[0046] In the first example, each main portion 51 extends from a tooth 43 by forming a bend (formed by a fold) at its longitudinal end and in the second example, the main portion 51 can extend from the base by forming a bend at its longitudinal end.

[0047] Each main portion is therefore configured to be housed in a cell 20.

[0048] In the second example shown in [Fig. 4], the axial retaining wall 4 is devoid of teeth and notches at the level of this external peripheral edge 4e; only the fold formed at the longitudinal end of the main portion 51 of each wedge 5, extending from the base 42, creates an additional thickness relative to the peripheral edge 4e. In other words, in this example the axial retaining wall 4 comprises only the base 42, shaped like a circular crown section (ring sector centered on the X-axis), whose external peripheral edge 4e is rounded with respect to the X-axis.

[0049] In this case, the main portion 51 comprises two faces opposite each other, in the shape of a rectangular parallelogram, and two longitudinal edges joining the two opposite faces, each longitudinal edge extending longitudinally in a plane parallel to the X axis and each of the edges along a longitudinal direction inclined with respect to a line parallel to the X axis passing through the portion of the peripheral edge 4e. One of the faces of the main portion 51 is therefore configured to be opposite a blade foot 32, such as that shown for example in [Fig.1A] and the other face opposite a cell bottom such as cell 20 of disk 2 in [Fig.1A],

[0050] Each wedge 5 further comprises a second axial retaining wall 53 extending from the main portion 51 to the opposite side of the peripheral edge portion 4e, perpendicular to the main portion. Each second axial retaining wall 53 is intended to axially retain a blade 3 such as that of [Fig. 1A].

[0051] In this case, in this example the plate P includes only two wedges 5 but according to other examples of this embodiment, the plate P could include more, for example 3, 4 etc, up to extending along a semicircle of the X axis.

[0052] In this case, in this example, the second axial retaining walls 53 and the teeth 43 are parallel and circumferentially offset from each other, the main portion 51 connecting the second axial retaining wall 53 and a tooth 43.

[0053] Thus the plate P reduces or prevents the pivoting of the wedges 5 in the alveoli 20.

[0054] A second plate P' according to a second embodiment, shown in Figures 5A and 5B, is identical to the plate P according to the first embodiment except that the plate P' comprises a base 42' in the shape of a ring having the X-axis as its axis and as many shims 5 as there are recesses 20 in a turbomachine disk 2. In this example, the plate P' comprises 18 of the shims 5. Each shim 5 is identical to that of the first embodiment. The axial retaining wall 4' thus comprises as many teeth 43, each identical to that of the first embodiment, as there are shims 5.

[0055] Fig. 5B represents this plate P' surrounding a disk 2 shown without its teeth 21 and its alveoli 20.

[0056] According to an example of these two embodiments, the plate P' is a cut and folded sheet metal forming the different wedges from the axial retaining wall.

[0057] The invention also relates to a turbomachine rotor assembly, comprising the X-axis disk 2, for example that of [Fig. 1A], comprising: • the first and second radial walls 23, 24, opposite each other, • teeth 21 at the radially external periphery of disc 2 • alveoli 20 formed between each pair of circumferentially adjacent teeth 21, each alveolus 20 comprising a base, the teeth 21 and the alveoli 20 each connecting the first radial wall 23 to the second radial wall 24 and a plate P according to one of the two embodiments in which the axial retaining wall 4 is mounted against the second axial wall 24 and in that the main portion 51 of each wedge 5 is housed in a cavity all along the bottom of the cavity 20.

[0058] Preferably, the rotor assembly includes a flange mounted on the side of the second radial face of the disk 2 to retain the blade foot in the opposite direction to the axial direction of insertion.

[0059] In particular, the rotor assembly includes a fresh air circuit opening onto each socket 20 and in which a space is formed between each tooth 21 forming the socket 20 and the main portion 51 of each wedge 5. The flange can allow the fresh air inlet channel to be formed with the disc.

[0060] For example, the rotor assembly belongs to a turbomachine rotor, for example a rotor used in a low-pressure turbine extending around a longitudinal axis classically comprising one or more rotor disks 2 carrying on their outer periphery a plurality of movable blades 3. The movable blades 3 have a radially internal part, or blade root, extended by a blade 30. These movable blades 3 are housed at their root 32 in the recesses 20 which open onto the outer peripheral surface of the rotor disk.

[0061] The positioning of the blade roots 32 in the recesses 20 of the rotor discs 2 is achieved by translation along a longitudinal insertion direction x' offset angularly with respect to the x-axis of the turbomachine. Each rotor stage can thus comprise the entire rotor assembly.

[0062] Thus the assembly can include movable blades 3 each comprising a blade foot 32 housed in a cavity 20 of the disk forming a turbine rotor stage of a turbomachine, for example a low pressure turbine or a blower rotor.

[0063] Each main portion 51 is thus situated between the bottom of the corresponding cavity 20 and the corresponding blade root 32, and each second axial retaining wall 53 is mounted against a radial surface of the corresponding blade root 32. The radial surface of the blade root 32 is therefore also inclined (beveled) with respect to the longitudinal direction x', i.e., with respect to the lateral surfaces of the blade root comprising the bearing surfaces.

[0064] The invention also relates to a turbomachine comprising such a turbomachine rotor assembly.

[0065] Unless otherwise specified, the same element appearing on different figures presents a unique reference.

Claims

Demands

1. A multi-axial wedge plate (P, P') for axially retaining blades (3) in recesses (20) of a turbomachine disk (2) centered on an X-axis, the plate comprising: - a first axial retaining wall (4, 4'), which is configured to be mounted abutting against a radial surface (24) of the disk (2), the first axial retaining wall (4, 4') comprising a radially external peripheral edge (4e) with respect to the X-axis, - at least two wedges (5) each comprising: • a main portion (51) extending longitudinally from the radially external peripheral edge (4e) of the axial retaining wall (4), each main portion (51) being configured to be mounted in a recess (20) of the disk (2), and • a second axial retaining wall (53) configured to cooperate with a blade root and extending, opposite each main portion (51),at the opposite longitudinal end of the first axial retaining wall (4, 4').,

2. Multi-wedge plate (P, P') according to any one of the preceding claims, wherein each main portion (51) extends longitudinally in a longitudinal direction (x') inclined with respect to the X axis.

3. Plate (P, P') with axial multi-wedges according to any one of the preceding claims, wherein the first axial retaining wall (4, 4') comprises a base (42) and teeth (43) extending radially, with respect to the X axis, projecting outwards from the base (42, 42') forming notches (44) between them, the outer peripheral edge (4e) being formed by the edge of the teeth (43) and the notches (44), each main portion (51) extending in a bend with respect to a tooth (43).

4. Plate (P) with axial multi-shims according to claim 2 or 3, wherein the base (42) is a ring or a ring sector centered on the X axis.

5. Plate (P') with axial multi-shims according to claim 2 or 3, comprising several main portions (51) regularly distributed around the X axis, each main portion (51) being configured to be mounted in a recess of the disc.

6. Plate (P, P') with multi axial wedges according to any one of the preceding claims, formed from a cut and bent sheet.

7. Turbomachine rotor assembly, comprising: - a disk (2) centered on an axis X, the disk (2) comprising: • a first and a second opposing radial surface (23, 24), • teeth (21) at the radially external periphery of the disk and • recesses (20) formed between each pair of two circumferentially adjacent teeth, each recess (20) comprising a bottom, the teeth (21) and the recesses (20) each connecting the first radial wall (23) to the second radial wall (24), - a multi-axial wedge plate (P, P') according to any one of the preceding claims, in which the first axial retaining wall (4, 4') is mounted against the second radial surface (24) and in that the main portion (51) of each wedge (5) is mounted along the bottom of a recess (20)).

8. Turbomachine rotor assembly, according to claim 7, further comprising blades (3) each comprising a blade foot (32) mounted in a cavity (20) of the disk (2), each wedge (5) comprising: - the main portion (51) between the bottom of the corresponding cavity (20) and the corresponding blade foot (32), - the second axial retaining wall (53) mounted against a radial surface of the blade foot (32).

9. Turbomachine rotor assembly, according to the preceding claim, comprising a ventilation air circuit opening into each cell (20) of the disc (2).

10. Turbomachine comprising a turbomachine rotor assembly, according to the preceding claim.

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