Assembly for a compressor rotor of a turbine engine

Abstract

The invention relates to an assembly for a compressor rotor of a turbine engine having a longitudinal axis (X), the rotor comprising a plurality of discs (8) mounted so as to be rotatable about the longitudinal axis (X) and coupled together by Curvic-type coupling, the assembly being configured to be mounted so as to be rotatable about the longitudinal axis (X) and comprising: • - a tie-rod (1) having a non-threaded outer surface, • - a journal (2) configured to exert an axial pressure on the discs (8) in a direction opposite to an axial pressure exerted by the tie-rod (1) on the discs (8) so as to ensure the coupling between the discs (8), the assembly further comprising means for blocking axial translation which are configured to exert an elastic force on the journal (2) so as to keep the journal (2) in contact with the discs (8), the means for blocking axial translation comprising: - a lug (10) projecting from the outer surface of the tie-rod (1), and - a wedge (3) having a first wedge portion (31) bearing axially against the journal (2) so as to block the radial translation of the journal (2), and a second wedge portion (32) bearing radially against the journal (2) so as to block the axial translation of the journal (2), the wedge (3) and the lug (10) being assembled by dog clutch coupling.

Description

[0001] DESCRIPTION

[0002] TITLE: TURBOMACHINE COMPRESSOR ROTOR ASSEMBLY

[0003] Scope of the invention

[0004] The present invention relates to the field of aircraft turbomachinery.

[0005] More particularly, the invention relates to a turbomachine compressor, and more particularly to a turbomachine compressor rotor assembly.

[0006] Prior art

[0007] Typically, a turbomachine comprises several components such as one or more compressors and one or more turbines. Compressors and turbines are constructed in a known manner by alternating moving disks, also called rotor disks, and stationary disks, also called stator disks.

[0008] 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 to ensure the clamping of the rotor discs to each other and also to ensure the coupling of these rotor discs to the turbomachine shaft.

[0009] To ensure the rotor discs and journals remain compressed against each other, they are assembled using fasteners, particularly on the rotation shaft. For example, these fasteners may include a threaded hole on the shaft, coupled with one or more locking nuts, to ensure the axial and radial positioning of each disc, as well as compression between the discs and the journals.

[0010] However, threaded assemblies are complex to dimension for fatigue resistance, primarily due to the thread geometry and the material composition of the threads. 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, as the greater the thread depth, the lower the fatigue resistance. Conversely, a shallow thread depth increases the number of threads that must be engaged, thus increasing the shaft's length and, consequently, its mass.

[0011] Furthermore, engine shafts are components with a declared lifespan registered with certification authorities, meaning they are all inspected before being put into service to prevent any cracks from appearing or developing. This, in turn, creates control difficulties due to the complexity of the assembly once completed.

[0012] There is therefore a need to provide a solution to facilitate the implementation and control of such a rotor, and more specifically the assembly of the rotor, without compromising its performance.

[0013] Description of the invention

[0014] The invention aims to remedy at least in part the aforementioned drawbacks relating to prior art techniques.

[0015] To this end, the invention relates to an assembly for a turbomachine compressor rotor of longitudinal axis X, said rotor comprising a plurality of discs mounted movably in rotation 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 having an external unthreaded surface, a trunnion configured to exert an axial pressure on said discs in a direction opposite to an axial pressure exerted by said drawbar on said discs so as to ensure the coupling between said discs, said assembly further comprising axial translation locking means configured to exert an elastic force on said trunnion so as to maintain said trunnion in contact with said discs.

[0016] Thus, the solution offers a new and inventive approach that makes it possible to resolve at least some of the drawbacks of the prior art.

[0017] In particular, by implementing a pulling shaft with 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, it is possible to implement 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, where the first thread undergoes irreversible deformations, independent of time, involving dislocation movements.

[0018] In addition, this allows for more leeway in the mechanical strength of the rotating shaft and the associated locking system.

[0019] 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, said wedge and said lug being assembled by dog ​​engagement.

[0020] 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.

[0021] 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.

[0022] 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 axial contact with said drawbar in the vicinity of said lug, said first locking portion being inserted into the lug and into said third wedge portion. 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 formed in contact with said second locking portion and said second wedge portion.

[0023] 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.

[0024] 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.

[0025] This allows the forces to be distributed over the entire extent of the rotor discs and the trunnion. The invention also relates to a turbomachine compressor rotor, comprising a plurality of discs mounted to rotate freely 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 downstream of said discs, the 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. The invention also relates to an aircraft turbomachine comprising a compressor according to the aforementioned embodiment.

[0027] According to a particular aspect of at least one embodiment of the invention, the turbomachine is a turbojet.

[0028] Presentation of the figures

[0029] The invention, and its various advantages, will be more easily understood in 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 other schematic views of part of an assembly 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. SA], [Fig. 6B] and [Fig. 6C] are three further schematic views of part of an assembly 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 further 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 this 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 it. Therefore, the direction along the axis R corresponds to a radial direction. Similarly, the adjectives "inner" (or "internal") and "outer" (or "external") are used with reference to this radial direction, such that the inner part of an element is, along this radial direction, closer to the longitudinal axis X than the outer part of the same element. With reference first to Figure 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 turbojet 901 has a central longitudinal axis X around which its various components extend. It comprises, from upstream to downstream along a main direction 905 of gas flow through this turbojet, 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.

[0040] 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 rotating wheels, called rotor wheels, and stationary wheels, called stator wheels.

[0041] In the presented solution, the rotor comprises a plurality of discs mounted to rotate about the longitudinal axis X and coupled to each other by a Curvic®-type coupling, i.e., by means of complementary recesses allowing mechanical coupling of the discs. The principle of the invention is based on the implementation, within a rotor, of an assembly comprising axial translation locking means configured to exert an elastic force on a trunnion so as to maintain this trunnion in contact with the rotor discs.

[0042] According to one embodiment of the invention, the rotor may comprise an assembly located upstream of the discs and an assembly located downstream of the discs, the upstream and downstream aspects being defined by the direction of gas flow within the turbomachine. Each of these assemblies is configured to be mounted for rotation about said longitudinal axis X.

[0043] An embodiment of the invention is subsequently presented with reference to Figures 2 to 7B. As illustrated, the assembly comprises: a drawbar 1 having an unthreaded external surface, and a trunnion 2 configured to exert axial pressure on the discs 8 in a direction opposite to the axial pressure exerted by the drawbar 1 on the discs 8, so as to ensure coupling between the discs 8. In other words, the trunnion 2 can exert axial tensile pressure on the discs in a downstream direction while the drawbar 1 exerts axial tensile pressure on the discs in an upstream direction.

[0044] 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.

[0045] More specifically, 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.

[0046] 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.

[0047] 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.

[0048] Depending on the embodiments, and in order to balance the axial tensile forces, the means of blocking in axial translation can extend circularly around the longitudinal axis X.

[0049] In this embodiment, the means for blocking axial translation include: a lug 10 formed projecting from the outer surface of the drawbar 1, and a wedge 3.

[0050] 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.

[0051] 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.

[0052] Here, the wedge 3 and the lug 10 are assembled by a dog clutch. 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 a dog clutch at the level of the third wedge portion 33.

[0053] Figures 5A to 5C show this step of setting up the wedge with the trunnion and the drawbar.

[0054] 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. 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.

[0055] Because of this stop 5, the second portion of wedge 32 is in indirect radial support with the trunnion 2.

[0056] 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.

[0057] 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.

[0058] Figures 6A to 6C show this step of installing the lock on the assembly of figures 5A to 5C.

[0059] As illustrated in Figures 7A and 7B, the means for blocking in axial translation 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.

[0060] More particularly, and as can be seen in Figure 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 shaft 1.

[0061] Figures 7A and 7B show this step of installing the axial retaining ring on the assembly of figures 6A to 6C.

[0062] It should be noted that only one assembly is represented in the various figures. However, as mentioned previously, it is possible to implement an upstream assembly and a downstream assembly with a plurality of rotor discs arranged between this upstream assembly and this downstream assembly, such 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 for rotation 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 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),said axial translation locking means comprising: a lug (10) 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.

2. Assembly according to claim 1, 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).

3. Assembly according to any one of claims 1 or 2, characterized in that said axial translation locking means further comprise a lock (4) having a first lock portion (41) bearing axially against said wedge (3) so as to block said wedge (3) in radial translation relative to said lug (10), and a second lock portion (42) bearing radially against said wedge (3) so as to block said wedge (3) in axial translation relative to said lug (10).

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

5. Assembly according to any one of claims 3 or 4, 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).

6. Assembly according to claim 5, 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).

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

8. 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.

9. Turbomachine compressor characterized in that it comprises a turbomachine compressor rotor according to claim 8.

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

11. Aircraft turbomachine according to claim 10, characterized in that it is a turbojet.

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