SPLIT ENGINE MODULE MOVABLE WHEEL, FEATURING AN IMPROVED AXIAL SPLIT FUNCTION

Abstract

The invention relates to a bladed rotating wheel (12B) of an aircraft turbomachine module, comprising a disc (20), as well as at least one rotating blade (30) having a blade foot (31) housed in a cavity (28) of the disc, the rotating wheel also comprising an axial retention element (52) of the blade (30) in its cavity (28), the disc (20) comprising a first part (22a) having a first radially external end (50a) defining a first portion of cavity (28a), and a second disc part (22b) having a second radially external end (50b) defining a second portion of cavity (28b). Furthermore, the retaining member (52) is arranged to cooperate on one side with a first axial stop face (54a) formed on the first disc portion (22a), and on the other side with a second axial stop face (54b) formed on the second disc portion (22b). Figure for the abbreviation: Fig. 2

Description

Title of the invention: Bladed rotating wheel of an aircraft turbomachine module, featuring an improved axial blade retention function technical field

[0001] The present invention relates to an aircraft turbomachine, preferably of the turbojet or turboprop type.

[0002] More particularly, the invention relates to a bladed rotating wheel of an aircraft turbomachine module, for example a turbine. This type of rotating wheel is known, for example, from document FR 2 825 748 A1. The invention relates more specifically to the axial retention function of the blades of this rotating wheel. Prior art

[0003] A bladed rotor of an aircraft turbomachine module generally comprises a disk and movable blades, each having a blade root housed in a recess of the disk. The rotor usually includes an axial retention device for the blades in their recesses. This device takes the form of an axial blade retention ring, which is housed on one side in a hook under the platform of each blade and on the other side held in position by a flange clamped onto the other components of the module's rotor.

[0004] This technical solution, although widespread, can still be improved for the following reasons.

[0005] First, mounting the retaining ring onto the rotating wheel remains a delicate operation. This mounting operation is time-consuming and may require the use of a tool to facilitate assembly, such as a mallet. The use of the mallet by operators carries a risk of damaging the ring, as well as nearby parts, whose lifespan may be affected.

[0006] Furthermore, during operation, the axial retention ring of the blades is subjected to mechanical and thermal stresses, including alternating expansion and contraction. This exposes the ring to the risk of cracking, which can lead to the release of ring fragments into the stream, with the associated risk of damage to the blades located downstream.

[0007] To avoid these problems, the axial retaining ring of the blades has to be changed before it becomes too fragile, and this via a costly operation of removing the turbomachine.

[0008] Finally, another drawback of this solution using a retention ring is the need to clamp it against the disc. of the flange, usually using bolts. To limit the stress applied to the ring and its risk of damage, it is necessary to limit the tension in the bolts, which is undesirable for the other rotor components fixed together by these same bolts. Description of the invention

[0009] To address at least partially the drawbacks mentioned above, relating to prior art achievements, the invention first of all relates to a bladed moving wheel of an aircraft turbomachine module, the moving wheel being centered on a longitudinal central axis, and comprising a disc, as well as at least one moving blade having a blade foot housed in a cavity of the disc, the moving wheel also comprising an axial retention element of the blade in its cavity.

[0010] According to the invention, the disc comprises a first disc part and a second disc part assembled to the first disc part, the first disc part having a first radially external end defining a first portion of the cavity, and the second disc part having a second radially external end defining a second portion of the cavity axially adjacent to the first portion of the cavity, and the axial retention member is made or mounted on the blade, being arranged so as to cooperate on one side with a first axial stop face made on the first radially external end of the first disc part, and on the other side with a second axial stop face made on the second radially external end of the second disc part.

[0011] The invention provides numerous advantages, foremost among them the elimination of the axial retaining ring for the blades, and potentially the elimination of its retaining flange. By reducing the number of parts, a lower overall mass for the rotating wheel results. As such, the invention therefore represents a result of technological research aimed at significantly improving aircraft performance, and, in this sense, contributes to reducing the environmental impact of these aircraft (decarbonization).

[0012] Furthermore, removing the ring simplifies the wheel assembly and reduces the risk of damage to its components during assembly. Moreover, thanks to the solution provided by the invention, there is no longer any risk of ring fragments being lost in the vein.

[0013] Another advantage of the invention lies in the fact that the disc is made in several parts. Each disc part can thus be made from a blank, for example a casting, smaller in size than in the prior art. This reduces the risk of defects in the material, and in the event of the need for disposal, the The volume of the defective raw part advantageously presents a smaller volume, thus resulting in a limited loss.

[0014] The invention preferably provides for at least one of the following optional technical features, implemented individually or in combination.

[0015] Preferably, the axial retention member is housed at least partly in a notch made in one and / or the other of the first and second radially external ends, said notch being axially delimited between the first and second axial stop faces.

[0016] Preferably, the axial retention member is an outgrowth projecting outward from the blade foot, and / or from a blade platform, and preferably the outgrowth is arranged so as to extend axially in a median plane of the blade foot.

[0017] As mentioned above, the axial retention member can be made in one piece with the blade, or be attached to it, for example in a notch provided for this purpose on the blade.

[0018] Preferably, the first and second parts of the disk each form a half-disk.

[0019] Preferably, the first and second disk sections comprise means for radially centering one relative to the other, so as to properly distribute the forces induced by the centrifugal effect during operation. Preferably, these radial centering means comprise an axially projecting groove on one of the first and second disk sections, and a groove on the other of the first and second disk sections, the groove penetrating axially into the groove.

[0020] Preferably, the first and second parts of the disk are annular, centered on the central longitudinal axis.

[0021] Preferably, the movable wheel includes axial fixing means of the first disc part on the second disc part, these axial fixing means preferably comprising screws or bolts distributed circumferentially around the longitudinal central axis.

[0022] Preferably, the moving wheel is devoid of an axial retaining ring for the blade.

[0023] The invention also relates to an aircraft turbomachine module comprising at least one such rotating wheel, the module preferably being a turbine, and even more preferably a low-pressure turbine. The application of the invention to a compressor also remains possible.

[0024] Finally, the invention also relates to an aircraft turbomachine, comprising at least one such module.

[0025] Other advantages and features of the invention will become apparent from the following detailed, non-limiting description. Brief description of the drawings

[0026] The detailed description that follows refers to the accompanying drawings in which:

[0027] [Fig-1] is a schematic axial cross-sectional view of a turbojet engine according the invention;

[0028] [Fig.2] is a half-axial cross-sectional view of part of a turbine stage of the turbomachine shown in the previous figure, the turbine stage comprising a moving wheel being in the form of a preferred embodiment of the invention;

[0029] [Fig.3] is an enlarged perspective view of part of the wheel shown in [Fig.2];

[0030] [Fig.4] is an even more enlarged perspective view of part of the wheel shown in [Fig.3];

[0031] [Fig. 5] is an even more enlarged perspective view of another part of the wheel shown in [Fig. 3]; and

[0032] [Fig.6] is a cross-sectional view of part of the wheel shown in Figures 3 to 5. Detailed description of implementation methods

[0033] The figures include a reference frame L, R and C defining respectively longitudinal, radial and circumferential directions orthogonal to each other, these directions corresponding to those of an aircraft turbojet 1 according to the invention.

[0034] [Fig. 1] represents the aircraft turbojet 1, preferably having a twin-spool, twin-flow design. However, other types of turbojets are possible, as are turbomachines other than turbojets, such as turboprops.

[0035] Hereafter, the terms "upstream" and "downstream" are defined with respect to a principal direction DI of gas flow through the turbojet 1 when it is operating in direct thrust mode. The direction DI is parallel to the longitudinal direction L, and also parallel to a longitudinal axis Al of the turbojet, around which its various components extend. In this case, from upstream to downstream of the turbojet 1, these components are a fan 4, a low-pressure compressor 5, a high-pressure compressor 6, a combustion chamber 7, a high-pressure turbine 8, and a low-pressure turbine 9.

[0036] During the operation of the turbojet engine 1, an airflow 10 enters the turbojet engine 1 through an air inlet 3, passes through the fan 4, and then splits into a central primary flow 10A and a secondary flow 10B. The primary flow 10A flows in a main gas circulation channel 11A passing through the compressors 5 and 6, the combustion chamber 7, and the turbines 8 and 9. The secondary flow 10B flows as to it in a secondary vein 1 IB surrounding the main vein 11 A, also called primary vein, or aerodynamic flow vein.

[0037] In a manner known per se, a turbine such as the high-pressure turbine 8 or the low-pressure turbine 9 comprises one or more stages 12. Each stage 12 comprises a stator assembly 12A including a distributor 29, also called a stator bladed ring, and a cutting wheel 12B, arranged directly upstream of the assembly 12A. Such a stage 12 is shown in [Fig.2].

[0038] With reference now to figures 2 to 6, the turbine wheel 12B will be described, here preferably integrated into the high-pressure turbine, and centered on the axis Al.

[0039] One of the features of the invention lies in the fact that the rotating wheel 12B comprises a turbine disc 20 centered on the axis Al, around which it extends in the direction C, and made by assembling several separate parts. In the preferred embodiment described below, these are two separate parts assembled together, each obtained separately, for example from as-cast pieces.

[0040] The rotating wheel 12B also includes rotating blades 30, forming an annular row of blades centered on the axis AL. Each rotating blade 30 comprises, successively, in the radial direction R from the inside out, a blade root 31, a platform 33, and a blade 35. The platform 33 delimits, radially inward, the main duct 11A of the turbojet. Furthermore, each blade root 31 is housed in a recess 28 of the disk 20. More precisely, on the outer periphery of this disk 20, radial teeth 26 are defined, between which the recesses 28 are formed for housing the blade roots 31. The recesses 28 are thus circumferentially spaced from one another, each being axially open, preferably in both directions. As is known, each cell 28 is adapted so as to be able to radially house and retain the foot 31 of a blade 30, of complementary shape.To achieve this, the blade foot is, for example, bulb-shaped, or it forms a so-called "fir tree attachment" with cell 28. Also, each cell 28 can have a general shape that narrows radially outwards, or radially inwards.

[0041] As mentioned above, the disk 20 comprises a first part 22a and a second part 22b, each annular in shape centered on the axis Al, and both made of the same or different materials. In the preferred embodiment described, the first and second parts 22a, 22b form two half-discs, symmetrical or substantially symmetrical in shape with respect to a median transverse plane of the wheel 12B and the disk 20, which also corresponds to an interface plane between these two parts.

[0042] Therefore, in what follows, only one of the first and second parts 22a, 22b will be described, while in the figures, the symmetrical portions of the two parts 22a, 22b will bear numerical references with the extension "a" for the first part 22a, and with the extension "b" for the second part 22b.

[0043] Each of the first and second parts 22a, 22b has an annular shape, centered on the axis Al. Each of them defines a part 44a, 44b of a disc bore 44 centered on the axis Al, this bore allowing the axial passage of one or more drive shafts 46 through the disc.

[0044] The bore 44 is defined at the level of an inner periphery of parts 22a, 22b. This is a region of the disc that is axially thickened, then narrows radially outwards, before widening axially again at the outer periphery. At this outer periphery, the first part 22a has a first radially external end 50a defining a first portion of the alveolus 28a, just as the second part 22b has a second radially external end 50b defining a second portion of the alveolus 28b. The second portion of the alveolus 50b is axially adjacent to the first portion of the alveolus 50a, with axial contact preferentially observed between these two elements, or a small axial gap possibly remaining.

[0045] In other words, on the disk 20, each cavity 28 is obtained by combining a first portion of cavity 28a and a second portion of cavity 28b located in its axial extension. It is noted that the cavities can be pinned together by assembling the two half-disks 22a, 22b, to ensure the centering of the two half-cavities 28a, 28b.

[0046] Preferably, all the alveoli of the disc 20 are designed in this way, being distributed in the form of an annular row around the AL II axis, so the same is true for each tooth 26, made by two axially adjacent tooth portions, belonging respectively to the two radially external ends 50a, 50b.

[0047] Subsequently, the cooperation between one of the movable blades 30 and its associated cavity 28, reconstituted by the association of the two portions of cavity 28a, 28b, will be described. However, it is noted that this cooperation is preferentially identical or similar for several of the movable blades 30 of the wheel 12B, or even for all of them.

[0048] Another feature of the invention lies in the implementation of the axial retention function of these blades 30 in their respective recesses 28. To this end, for each movable blade 30, an axial retention element 52 is provided, the shape of which differs radically from prior solutions. More precisely, the axial retention element 52 is formed as a single unit with the blade, or mounted on it, for example, in a notch in the blade 30. In the preferred embodiment shown In the figures, the retention member 52 is made in one piece with the blade, in the form of a projecting outgrowth extending circumferentially from the blade foot 31, and / or extending radially inwards from the platform 33. This retention member 52 is preferably arranged axially centered with respect to the blade foot 31, that is to say, it extends axially in a median plane of the blade foot 31.

[0049] The retention member 52 takes the form of a tongue, a pin, or any other similar element, of negligible axial thickness with regard to the axial length of the blade foot 31, a ratio less than 0.1 being preferentially retained.

[0050] This retaining member 52 is arranged so as to cooperate on one side with a first axial stop face 54a made on the first radially external end 50a of the first part of the disc 22a, and on the other side with a second axial stop face 54b made on the second radially external end 50b of the second part of the disc 22b.

[0051] To this end, the retaining member 52 is housed at least partially in a notch 56, shown in [Fig. 4], and formed in one and / or the other of the first and second radially external ends 50a, 50b. The notch 56 also opens radially outwards and is axially delimited between the first and second axial stop faces 54a, 54b. In this preferred embodiment, the notch 56 is formed by two half-notches extending axially from one another, and respectively formed on the first and second radially external ends 50a, 50b. Furthermore, the notch 56 is preferably formed at the radially external end of one of the teeth 26 of the disc, as can be seen in [Fig. 4].

[0052] With reference to [Fig.6], it is noted that each movable blade 30 can in fact comprise two axial retaining members 52, on either side of the disc 31 in the circumferential direction C. In this case, the two axial retaining members 52, each having the form described above, cooperate respectively with two notches 56, themselves provided respectively on two directly consecutive teeth 26 of the disc 20. Thus, each tooth 26 of the disc is provided with two adjacent notches 56 to cooperate respectively with two directly consecutive movable blades 30, as shown in [Fig.4] (on which only one of the two blades has been shown).

[0053] The first and second disc parts 22a, 22b are equipped with means for radially centering one relative to the other. These means may take the form of an annular groove 58 provided on one of the two parts 22a, 22b, and receiving a complementary element 60, for example in the form of a ridge, provided on the other of these two parts 22a, 22b. These elements 58, 60 are centered on the AL axis. Their cooperation then occurs preferentially at the interface between the two parts 22a, 22b. It allows for the proper distribution of forces induced by the centrifugal effect during the operation of the turbojet engine.

[0054] Finally, it is noted that to fix the two parts 22a, 22b together, the wheel 12B includes axial fastening means, preferably in the form of axial bolts 62, or similar fastening elements, such as rivets. Each bolt 62 passes through two aligned through holes 64a, 64b made through the two parts 22a, 22b, so as to apply an axial clamping force to these two axially stacked parts. These are preferably the same bolts as those used for fixing the wheel 12B to the other wheels of the module. These bolts 62 are distributed circumferentially around the longitudinal central axis Al.

[0055] To assemble the rotating wheel 12B, it is sufficient to bring the two disc parts 22a, 22b axially closer together, ensuring that the portions of the recesses 28a, 28b are progressively penetrated by their corresponding blade root portions 31. This causes the axial retaining elements 52 to engage in their notches 56 formed by the joining of the two disc parts 22a, 22b, after which the bolts 62 can be tightened.

[0056] The invention thus advantageously eliminates the need for a conventional axial retention ring, and the retaining flange for this ring can also be removed. However, such a flange can be retained on the movable wheel 12B, particularly for cooling purposes for the disk 20.

[0057] Of course, various modifications can be made by a person skilled in the art to the invention which has just been described only by way of non-limiting examples, and within the limits of the scope of the annexed claims.

Claims

Demands

1. A bladed drive wheel (12B) of module (8, 9) of an aircraft turbomachine, the drive wheel being centered on a central longitudinal axis (Al), and comprising a disk (20), as well as at least one drive blade (30) having a blade root (31) housed in a recess (28) of the disk (20), the drive wheel also comprising an axial retention element (52) for the blade (30) in its recess (28), characterized in that the disk (20) comprises a first disk portion (22a) as well as a second disk portion (22b) assembled to the first disk portion (22a), the first disk portion (22a) having a first radially external end (50a) defining a first recess portion (28a), and the second disk portion (22b) having a second radially external end (50b) defining a second recess portion. (28b) axially adjacent to the first portion of the alveolus,and in that the axial retention member (52) is made or mounted on the blade (30), arranged so as to cooperate on one side with a first axial stop face (54a) made on the first radially external end (50a) of the first disc part (22a), and on the other side with a second axial stop face (54b) made on the second radially external end (50b) of the second disc part (22b).

2. Movable wheel according to claim 1, characterized in that the axial retention member (52) is housed at least in part in a notch (56) made in one and / or the other of the first and second radially external ends (50a, 50b), said notch (56) being axially delimited between the first and second axial stop faces (54a, 54b).

3. Movable wheel according to claim 1 or 2, characterized in that the axial retention member (52) is an outgrowth projecting outward from the blade foot (31), and / or from a platform (33) of the blade (30), and preferably the outgrowth being arranged so as to extend axially in a median plane of the blade foot (31).

4. Movable wheel according to any one of the dependent claims, characterized in that the first and second parts of the disc (22a, 22b) each form a half-disc.

5. A movable wheel according to any one of the dependent claims, characterized in that the first and second disc parts (22a, 22b) comprise radial centering means (58, 60) of one with respect to the other, these radial centering means (58, 60) preferably comprising a groove (60) axially projecting from one of the first and second disc parts (22a, 22b), and a groove (58) on the other of the first and second disc parts (22a, 22b), the groove (60) penetrating axially into the groove (58).

6. Movable wheel according to any one of the dependent claims, characterized in that the first and second parts of the disc (22a, 22b) are annular and centered on the longitudinal central axis (Al).

7. Movable wheel according to any one of the dependent claims, characterized in that it comprises axial fixing means (62) of the first disc part (22a) on the second disc part (22b), these axial fixing means (62) preferably comprising screws or bolts distributed circumferentially around the longitudinal central axis (Al).

8. Movable wheel according to any one of the dependent claims, characterized in that it is devoid of an axial retaining ring for the blade.

9. Aircraft turbomachine module (8, 9) comprising at least one wheel (12B) according to any one of the preceding claims, the module being preferably a turbine, and even more preferably a low-pressure turbine.

10. Aircraft turbomachine (1), comprising at least one module (8, 9) according to the preceding claim.

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