TURBOMACHINE COMPRESSOR ROTOR ASSEMBLY

Abstract

The invention relates to a turbomachine compressor rotor assembly with a longitudinal axis (X), said rotor comprising a plurality of discs (8) mounted for rotation about said longitudinal axis (X) and coupled to each other by a Curvic® type coupling, said assembly being configured to be mounted for rotation about said longitudinal axis (X) and comprising: a drawbar shaft (1) having an unthreaded external surface, a trunnion (2) configured to exert an axial pressure on said discs (8) in a direction opposite to an axial pressure exerted by said drawbar shaft (1) on said discs (8) so as to ensure coupling between said discs (8), said assembly further comprising axial translation locking means configured to exert an elastic force on said trunnion (2) so as to maintain said trunnion (2) in contact with said discs (8). Figure 7A.

Description

Title of the invention: TURBOMACHINE COMPRESSOR ROTOR ASSEMBLY Scope of the invention

[0001] The present invention relates to the field of aircraft turbomachinery.

[0002] More particularly, the invention relates to a turbomachine compressor, and more specifically to a turbomachine compressor rotor assembly. Prior art

[0003] Conventionally, a turbomachine comprises several components such as one or more compressors and one or more turbines. Compressors and turbines are made in a known manner by the alternation of moving disks, otherwise called rotor disks, and stationary disks, otherwise called stator disks.

[0004] More specifically, within a rotor, for example a compressor rotor, a plurality of discs arranged around the longitudinal axis are axially aligned. A rotor also includes an upstream journal and a downstream journal so as to ensure the clamping of the rotor discs to each other and also to ensure the coupling of these rotor discs with the turbomachine shaft.

[0005] In order to ensure that the rotor discs and journals remain compressed against each other, the rotor discs and journals are assembled using fasteners, particularly on the axis of rotation. For example, these fasteners may include a threaded hole on the axis associated with one or more clamping nuts, so as to ensure the axial and radial positioning of each disc, and also the compression of the discs against each other and against the journals.

[0006] However, threaded assemblies are complex to dimension for fatigue resistance, particularly due to the geometry of the threads and the material composition within them. Specifically, regarding thread geometry, the threads must be fine to avoid reducing the shaft's mechanical strength, but they must also be deep enough to withstand the axial locking force. Indeed, a significant thread depth impacts the shaft's fatigue resistance, since the greater the thread depth, the lower the fatigue resistance. Conversely, a thread depth that is too shallow increases the number of threads that must be engaged and thus increases the shaft's length, and therefore its mass.

[0007] Furthermore, the motor shafts are parts with a declared service life registered with the certification authorities, which implies that they are all inspected before being put into service. circulation is necessary to prevent the appearance or creation of cracks. This, in turn, creates control difficulties due to the complexity of the assembly once completed.

[0008] There is therefore a need to provide a solution to facilitate the implementation and control of such a rotor and more particularly of the assembly of the rotor, while not harming its performance. Description of the invention

[0009] The invention aims to remedy at least in part the aforementioned drawbacks relating to prior art techniques.

[0010] To this end, the invention relates to an assembly for a turbomachine compressor rotor with a longitudinal axis X, said rotor comprising a plurality of discs mounted to rotate freely around said longitudinal axis X and coupled to each other by a Curvic® type coupling,

[0011] said assembly being configured to be mounted rotatably about said longitudinal axis X and comprising: - a drawbar with an unthreaded external surface, - a trunnion configured to exert axial pressure on said discs in a direction opposite to an axial pressure exerted by said shaft-pulling on said discs so as to ensure coupling between said discs,

[0012] said assembly further comprising axial translation locking means configured to exert an elastic force on said trunnion so as to keep said trunnion in contact with said discs.

[0013] Thus, the solution proposes a new and inventive approach that makes it possible to resolve at least in part some of the drawbacks of the prior art.

[0014] In particular, by implementing a pulling shaft having an external unthreaded surface and axial translation locking means configured to exert an elastic force on said trunnion so as to keep the trunnion in contact with the discs, this allows for a simpler assembly because the forces exerted on the trunnion and the discs are in the elastic range, which is a range where deformations are reversible, unlike a threaded type fixing, the first thread of which undergoes irreversible deformations, independent of time, involving dislocation movements.

[0015] In addition, this allows for more leeway on the mechanical strength of the rotating shaft and the associated locking system.

[0016] According to a particular aspect of at least one embodiment of the invention, said axial translation locking means comprise: - a lug formed projecting from said outer surface of said drawbar and - a wedge having a first portion of the wedge bearing axially with said trunnion so as to block said trunnion in radial translation, and a second portion of the wedge bearing radially with said trunnion so as to block said trunnion in axial translation,

[0017] said wedge and said lug being assembled by dog ​​clutching.

[0018] According to a particular aspect of at least one embodiment of the invention, said axial translation locking means further comprise a stop provided between said second wedge portion and said trunnion so that said second wedge portion is in indirect radial support with said trunnion.

[0019] According to a particular aspect of at least one embodiment of the invention, said axial translation locking means further comprise a lock having a first portion of the lock bearing axially against said wedge so as to block said wedge in radial translation relative to said lug, and a second portion of the lock bearing radially against said wedge so as to block said wedge in axial translation relative to said lug.

[0020] According to a particular aspect of at least one embodiment of the invention, said wedge has a third hollow wedge portion formed in continuity with said first wedge portion and configured to come into contact with said axially pulling shaft in the vicinity of said lug, said first locking portion being inserted into the lug and into said third wedge portion.

[0021] According to a particular aspect of at least one embodiment of the invention, said axial translation locking means further comprise an axial translation stop ring, provided in contact with said second portion of lock and said second portion of wedge.

[0022] According to a particular aspect of at least one embodiment of the invention, said second portion of the wedge has a groove formed on a lower surface opposite said drawbar. Furthermore, said axial translation stop ring is housed at least partially in said groove.

[0023] According to a particular aspect of at least one embodiment of the invention, said axial translation blocking means extend circularly around said longitudinal axis X.

[0024] This allows the forces to be distributed over the entire extent of the rotor discs and the trunnion.

[0025] The invention also relates to a turbomachine compressor rotor, comprising a plurality of discs mounted to rotate about said longitudinal axis X and coupled to each other by a Curvic® type coupling, the rotor comprising an assembly according to one of the aforementioned embodiments provided upstream of said discs, and an assembly according to one of the aforementioned embodiments provided in downstream of said discs, upstream and downstream being defined by the direction of gas flow within the turbomachine.

[0026] The invention also relates to a turbomachine compressor comprising a turbomachine compressor rotor according to the aforementioned embodiment.

[0027] The invention also relates to an aircraft turbomachine comprising a compressor according to the aforementioned embodiment.

[0028] According to a particular aspect of at least one embodiment of the invention, the turbomachine is a turbojet. Presentation of the figures

[0029] The invention, as well as its various advantages, will be more easily understood in the light of the following description of an illustrative and non-limiting embodiment thereof, and the accompanying drawings, among which:

[0030] [Fig-1] is a schematic cross-sectional view of an aircraft turbomachine;

[0031] [Fig.2] is a schematic exploded side view illustrating an assembly according to a first embodiment of the invention;

[0032] [Fig.3A] and [Fig.3B] are two schematic views of part of an assembly according to the first embodiment of the invention, during a step of setting up the trunnion relative to the drawbar;

[0033] [Fig.4A] and [Fig.4B] are two other schematic views of part of an assembly according to the first embodiment of the invention, during a step of setting up a stop on a wedge;

[0034] [Fig.5A], [Fig.5B] and [Fig.5C] are three further schematic views of part of a together according to the first embodiment of the invention, during a step of setting up the wedge and the stop with the trunnion and the drawbar;

[0035] [Fig.6A], [Fig.6B] and [Fig.6C] are three further schematic views of part of a together according to the first embodiment of the invention, during a step of installing a lock on the assembly of figures [Fig.5A], [Fig.5B] and [Fig.5C], and

[0036] [Fig.7A] and [Fig.7B] are two other schematic views of part of an assembly according to the first embodiment of the invention, during a step of setting up a rotating stop ring on the assembly of figures [Fig.6A], [Fig.6B] and [Fig.6C],

[0037] Detailed description of an embodiment of the invention

[0038] It should be noted that, throughout the description, the terms "upstream" and "downstream" are to be considered in terms of the main direction of gas flow within the turbomachine, and therefore at their arrival on the external surface of the inlet cone by way of the air flow F.

[0039] Furthermore, throughout the description, an axial direction corresponds to the direction of the longitudinal axis X and a radial direction is a direction orthogonal to the longitudinal axis X and intersecting the longitudinal axis X. Therefore, the direction along the axis R corresponds to a radial direction.

[0040] Similarly, the adjectives "interior" (or "internal") and "exterior" ("or external") are used with reference to this radial direction so that the interior part of an element is, along this radial direction, closer to the longitudinal axis X than the exterior part of the same element.

[0041] With reference first to [Fig. 2], an aircraft turbomachine 901 is shown, according to a preferred embodiment of the invention. This is a twin-spool, turbofan engine. However, it could be a turbomachine of another type, for example a turboprop, without departing from the scope of the invention. The turbofan engine 901 has a central longitudinal axis X around which its various components extend. It comprises, from upstream to downstream along a principal direction 905 of gas flow through this turbofan engine, a fan 903, a low-pressure compressor 904, a high-pressure compressor 906, a combustion chamber 911, a high-pressure turbine 907, and a low-pressure turbine 908.

[0042] Conventionally, after passing through the blower, the air splits into a central primary flow 912a and a secondary flow 912b that surrounds the primary flow. The primary flow 912a flows into a main gas circulation channel 914a, passing through the compressors 904, 906, the combustion chamber 911, and the turbines 907, 908. The secondary flow 912b flows into a secondary channel 914b, radially delimited outwards by an engine casing, surrounded by a nacelle 909. The compressors 904, 906 and the turbines 907, 908 are formed by alternating moving wheels, called rotor wheels, and fixed wheels, called stator wheels.

[0043] In the solution presented, the rotor comprises a plurality of discs mounted movably in rotation around the longitudinal axis X and coupled together by Curvic® type coupling, i.e. by means of complementary impressions allowing a mechanical coupling of the discs together.

[0044] The principle of the invention is based on the implementation of an assembly, within a rotor, comprising axial translation locking means configured to exert an elastic force on a trunnion so as to keep this trunnion in contact with the rotor discs.

[0045] According to one embodiment of the invention, the rotor may include an assembly provided upstream of the discs, and an assembly provided downstream of the discs, the upstream and downstream being defined by the direction of gas flow within the turbomachine. Each of these assemblies is configured to be mounted for rotation around said longitudinal axis X.

[0046] An embodiment of the invention is subsequently presented in relation to figures 2 to 7B.

[0047] As illustrated, the set comprises: - a drawbar 1 with an unthreaded external surface, - a trunnion 2 configured to exert an axial pressure on the discs 8 in a direction opposite to an axial pressure exerted by the drawbar 1 on the discs 8 so as to ensure coupling between the discs 8.

[0048] In other words, the trunnion 2 can exert an axial tensile pressure on the discs in a downstream direction while the pulling shaft 1 exerts an axial tensile pressure on the discs in an upstream direction.

[0049] According to one variant, the trunnion 2 can exert an axial tensile pressure on the discs in an upstream direction while the pulling shaft 1 exerts an axial tensile pressure on the discs in a downstream direction.

[0050] More particularly, the trunnion has a first trunnion portion 21 and a second trunnion portion 22, the trunnion 2 exerting pressure on the discs 8 via the second trunnion portion 22.

[0051] Figures 3A and 3B show this step of setting up the trunnion relative to the drawbar shaft as well as the axial tensile pressure force PI exerted by the trunnion 2 on the discs and the axial tensile pressure force P2 exerted by the drawbar shaft 1 on the discs.

[0052] In order to keep the trunnion 2 in contact with the discs 8, and thus to maintain the axial tensile pressure exerted by the trunnion 2 on the discs, the assembly further includes axial translation locking means configured to exert an elastic force on the trunnion 2.

[0053] According to the embodiments, and in order to balance the axial tensile forces, the means for blocking axial translation can extend circularly around the longitudinal axis X.

[0054] In this embodiment, the means for blocking axial translation include: - a lug 10 formed as a projection from the outer surface of the drawbar 1, and - a wedge 3.

[0055] As can be seen in particular in figures 5A to 5C, the wedge 3 has a first portion of wedge 31 bearing axially with the trunnion 2 so as to block the trunnion 2 in radial translation, and a second portion of wedge 32 bearing radially with the trunnion 2 so as to block the trunnion 2 in axial translation.

[0056] More specifically, in this embodiment, the first portion of wedge 31 bears axially against an underside of the first portion of trunnion 21 while the second portion of wedge 32 bears radially against a lateral side of the first portion of trunnion 21.

[0057] Here, the wedge 3 and the lug 10 are assembled by dog ​​engagement. More precisely, in this embodiment, the wedge 3 has a third hollow wedge portion 33 formed in continuity with the first wedge portion 31; the wedge 3 and the lug 10 are assembled by dog ​​engagement at the level of the third wedge portion 33.

[0058] Figures 5A to 5C show this step of setting up the wedge with the trunnion and the drawbar.

[0059] As can be seen in these figures, the means for blocking axial translation further include a stop 5 provided between the second portion of wedge 32 and the trunnion 2.

[0060] More particularly, this stop is housed between the second portion of wedge 32 and the first portion of trunnion 21, and comes into axial contact against an upper face of the first portion of wedge 31.

[0061] Due to this stop 5, the second portion of wedge 32 is in indirect radial support with the trunnion 2.

[0062] As can be seen in figures 6A to 6C, the means for locking in axial translation further include a lock 4 having a first portion of the lock 41 bearing axially against the wedge 3 so as to block the wedge 3 in radial translation relative to the lug 10, and a second portion of the lock 42 bearing radially against the wedge 3 so as to block the wedge 3 in axial translation relative to the lug 10.

[0063] More specifically, the first portion of the lock 41 is inserted into the lug 10 and into the third portion of the wedge 43 which is configured to come into contact with the drawbar 1 axially in the vicinity of the lug 10, while the second portion of the lock 42 comes to radial support against the first portion of the wedge 31.

[0064] Figures 6A to 6C show this step of setting up the lock on the assembly of Figures 5A to 5C.

[0065] As illustrated in Figures 7A and 7B, the axial translation locking means further include an axial translation stop ring 6, provided in contact with the second portion of the lock 42 and the second portion of the wedge 32.

[0066] More particularly, and as can be seen in [Fig.7B], the axial translation stop ring 6 fits at least partially into a groove 34 formed on a lower surface of the second portion of the wedge 42 provided opposite the drawbar 1.

[0067] Figures 7A and 7B show this step of placing the axial retaining ring on the assembly of Figures 6A to 6C.

[0068] It should be noted that only one assembly is represented in the various figures. However, and as mentioned previously, it is possible to implement an upstream assembly and a downstream assembly with a plurality of rotor discs provided between this upstream assembly and this downstream assembly, so that an upstream trunnion and a downstream trunnion each exert a force directed towards each other in order to maintain the compression of the rotor discs.

Claims

Demands

1. Assembly for a turbomachine compressor rotor of longitudinal axis (X), said rotor comprising a plurality of discs (8) mounted movably to rotate about said longitudinal axis (X) and coupled to each other by a Curvic® type coupling, said assembly being configured to be mounted rotatably about said longitudinal axis (X) and comprising: - a drawbar (1) having an external unthreaded surface, - a trunnion (2) configured to exert an axial pressure on said discs (8) in a direction opposite to an axial pressure exerted by said drawbar (1) on said discs (8) so as to ensure coupling between said discs (8), said assembly further comprising axial translation locking means configured to exert an elastic force on said trunnion (2) so as to maintain said trunnion (2) in contact with said discs (8).

2. Assembly according to claim 1, characterized in that said axial translation locking means comprise: - a lug (10) formed projecting from said outer surface of said drawbar (1), and - a wedge (3) having a first wedge portion (31) bearing axially with said trunnion (2) so as to block said trunnion (2) in radial translation, and a second wedge portion (32) bearing radially with said trunnion (2) so as to block said trunnion (2) in axial translation, said wedge (3) and said lug (10) being assembled by dog ​​engagement.

3. Assembly according to claim 2, characterized in that said axial translation locking means further comprise a stop (5) provided between said second wedge portion (32) and said trunnion (2) so that said second wedge portion (32) is in indirect radial support with said trunnion (2).

4. Assembly according to any one of claims 2 or 3, characterized in that said axial translation locking means further comprise a lock (4) having a first lock portion (41) coming into axial support against said wedge (3) so as to block said wedge (3) in radial translation relative to said lug (10), and a second portion of lock (42) coming into radial support against said wedge (3) so as to block said wedge (3) in axial translation relative to said lug (10).

5. Assembly according to claim 4, characterized in that said wedge (3) has a third hollow wedge portion (33) formed in continuity with said first wedge portion (31) and configured to come into contact with said drawbar (1) axially in the vicinity of said lug (10), said first locking portion (41) fitting into said lug (10) and into said third wedge portion (43).

6. Assembly according to any one of claims 4 or 5, characterized in that said axial translation locking means further comprise an axial translation stop ring (6), provided in contact with said second portion of lock (42) and said second portion of wedge (32).

7. Assembly according to claim 6, characterized in that said second portion of wedge (32) has a groove (34) formed on a lower surface provided opposite said drawbar (1), and in that said axial translation stop ring (6) fits at least partially into said groove (34).

8. Assembly according to any one of the preceding claims, characterized in that said axial translation blocking means extend circularly around said longitudinal axis (X).

9. Turbomachine compressor rotor, comprising a plurality of discs (8) mounted movable in rotation about said longitudinal axis (X) and coupled to each other by Curvic® type coupling, characterized in that it comprises an assembly according to any one of the preceding claims arranged upstream of said discs (8), and an assembly according to any one of the preceding claims arranged downstream of said discs (8), the upstream and downstream being defined by the direction of gas flow within the turbomachine.

10. Turbomachine compressor characterized in that it comprises a turbomachine compressor rotor according to claim 9.

11. Aircraft turbomachine characterized in that it comprises a compressor according to claim 10.

12. Aircraft turbomachine according to claim 11, characterized in that it is a turbojet.

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