AIRCRAFT TURBOMACHINE WITH PROTECTIVE SLEEVE STOP RING

Abstract

The invention relates to an aircraft turbomachine comprising: - a trunnion (32) integral with a rotor disk (30) configured to rotate about a longitudinal axis (XX'), and arranged coaxially around a sleeve (36) of a transmission shaft (34), the sleeve (36) comprising an annular wall relative to an annular wall of the trunnion surrounding it, the annular wall of the sleeve being pierced with circumferentially distributed holes (36a) each radially passing through the wall, the annular wall of the trunnion having circumferentially distributed recesses (32a), a system for locking the sleeve against rotation comprising a rod (38) provided with a pin (38c) extending radially from a radially external surface (38a) of the rod, the annular rod (38) being mounted such that the pin (38c) is radially engaged at both in a hole (36a) in the sheath (36) and in a housing (32a) opposite it. Fig.2

Description

Title of the invention: AIRCRAFT TURBOMACHINE WITH PROTECTIVE SHEATH STOP RING Technical field

[0001] The present disclosure relates to an aircraft turbomachine. Prior art

[0002] Aircraft turbomachine arrangements are known in which the turbomachine comprises a turbine, in particular a high-pressure turbine, comprising a rotor disk which is capable of rotating about a longitudinal axis of the turbomachine when the latter is in operation. The rotor disk is connected to a journal.

[0003] The turbomachine further comprises a transmission shaft which, for example, connects the rotors of a low-pressure compressor and a low-pressure turbine to each other. The turbomachine also comprises a high-pressure compressor and a high-pressure turbine, the rotors of which are connected to each other and surround the aforementioned transmission shaft. The transmission shaft extends axially inside a substantially cylindrical sleeve which protects it from the high temperatures of the aforementioned high-pressure elements during operation of the turbomachine. The journal and the protective sleeve are generally arranged coaxially with the journal which surrounds the sleeve.

[0004] In order to prevent rotation of the protective sheath during operation of the turbomachine, a system for blocking or stopping rotation of the protective sheath is provided.

[0005] For example, patent application FR 2 981 694 discloses a rotation blocking or stopping system which is generally positioned at one of the ends of the protective sheath. Statement of the invention

[0006] Although such a system is satisfactory, its design does not allow it to be positioned at another location in the sheath, for example at a distance from the ends of the latter.

[0007] The invention thus relates to an aircraft turbomachine comprising: - a sleeve of a rotor shaft of the turbomachine extending axially inside the sleeve, the journal being arranged coaxially around the sleeve, - a system for locking the sheath against rotation, characterized in that the sheath comprises a radially internal annular wall relative to a radially external annular wall of the journal which surrounds it, the annular wall of the sheath being pierced with a plurality of holes distributed in such a way circumferential and each passing through the annular wall of the sheath in a radial direction, the annular wall of the journal comprising a plurality of housings distributed circumferentially and each arranged in the journal in a radial direction, the rotation locking system of the sheath comprising a snap ring which is in the form of a split ring provided with a pin extending radially from a radially external surface of the split ring, the snap ring being mounted coaxially inside the annular wall of the sheath in such a way that the pin is engaged radially both in one of the radial holes in the annular wall of the sheath and in one of the housings opposite the annular wall of the journal.

[0008] The configuration of the annular ring equipped with a pin radially external to the latter allows the ring to be mounted at a distance from the ends of the sheath, where the installation of a conventional rotation locking system is not possible. Furthermore, the rotation locking system described above is particularly simple in design and the associated assembly and disassembly operations are also particularly simple to implement.

[0009] According to other possible characteristics, taken alone or in combination: - the annular wall of the sheath is shaped locally so as to form an axial stop against which the rod rests; - the annular wall of the sheath forms an axial stop against which the rod rests -the snap ring is an elastically deformable split ring which is provided with two free ends allowing it to be mounted inside the annular wall by bringing its free ends together; - each free end forms a return oriented radially towards the inside of the rod; -the pawn has a section taken in a plane perpendicular to the radial direction of extension of the pawn which has a shape chosen from the following shapes: circle, rectangle, oblong shape, oblong shape with flat(s), ellipse; - the annular wall of the sheath is arranged at a distance from the two opposite ends of the sheath; -the sheath has lips at one of its two opposite ends; -the journal is mounted in rotation in a casing of the turbomachine by means of at least one bearing located downstream of the ring; - said at least one bearing is mounted on the turbine side of the turbomachine; - the wipers provide a seal radially under said at least one bearing and axially in the vicinity of the latter. Brief description of the drawings

[0010] Other characteristics and advantages of the subject of the present disclosure will emerge from the following description of embodiments, given as non-limiting examples, with reference to the appended figures.

[0011] [Fig. 1] [Fig. 1] is a general schematic view in axial section of an aircraft turbomachine according to an embodiment of the invention;

[0012] [Fig.2] [Fig.2] is an enlarged schematic general view in axial half-section of the part of the turbomachine shown in [Fig.l] and which is surrounded by a frame C

[0013] [Fig.3] [Fig.3] is a general schematic perspective view showing one embodiment of the annular ring of [Fig.2];

[0014] [Fig.4] [Fig.4] is a schematic cross-sectional view of the protective sheath and trunnion assembly taken in plane P of [Fig.2];

[0015] [Fig.5] [Fig.5] is a general schematic perspective view of the interior of the protective sheath, the annular ring and the trunnion of [Fig.4]

[0016] [Fig.6A] [Fig.6A] is a partial schematic view of one embodiment of a pin engaged in a housing of the journal;

[0017] [Fig.6B] [Fig.6B] is a partial schematic view of another embodiment of a pin engaged in a housing of the journal;

[0018] [Fig.6C] [Fig.6C] is a partial schematic view of another embodiment of a pin engaged in a housing of the journal;

[0019] [Fig.6D] [Fig.6D] is a partial schematic view of another embodiment of a pin engaged in a housing of the journal. Detailed description

[0020] [Fig. 1] schematically illustrates in a longitudinal section an aircraft turbomachine 10 such as a dual-flow turbojet according to one embodiment of the invention. Other types of turbomachines may alternatively be envisaged.

[0021] The turbomachine 10 comprises here, from upstream to downstream according to the circulation of the air flow (from left to right in the figure), a fan 12, a low-pressure compressor 14, a high-pressure compressor 16, a combustion chamber 18, a high-pressure turbine 20 and a low-pressure turbine 22. All these elements exert their action in a known manner on a first annular air flow circulating in a first central duct 24 coaxial with the longitudinal axis XX' of the turbomachine. A second annular bypass duct 26 concentrically surrounds the first central duct 24 for the flow of a second annular air flow. Other turbojet configurations can alternatively be envisaged with a single compressor and a single turbine, or even with more than two compressors and more than two turbines.

[0022] The high pressure turbine 20 comprises in particular a rotor disk 30, also called a moving wheel, visible in [Fig.l] and shown in an enlarged and partial manner in [Fig.2] ([Fig.2] is an enlarged view of rectangle C in [Fig.l]). The rotor disc 30 is secured to a part 32 called a journal which extends downstream (to the right in [Fig.2]) from a downstream face 30a of the rotor disc (the upstream part of the disc is not shown in this figure).

[0023] The turbomachine further comprises a transmission shaft 34 which, here, connects the rotors of the low-pressure compressor 14 and the low-pressure turbine 22 to each other. The rotors of the high-pressure turbine 20 and the high-pressure compressor 16 are connected to each other and surround the transmission shaft 34. The transmission shaft 34 extends axially inside a sheath which is here a substantially cylindrical protective sheath 36 (even if, locally, the shape of the sheath may deviate from that of a cylinder) which protects it from the high temperatures prevailing in the high-pressure module (compressor 16 and turbine 20) during operation of the turbomachine. The journal 32 and the protective sheath 36 are generally arranged coaxially with the journal surrounding the sheath, the assembly of the two parts also being arranged coaxially with the longitudinal axis XX'.

[0024] The turbomachine also comprises an annular ring 38 shown in perspective in [Fig. 3] which comprises two opposite peripheral surfaces, namely an external peripheral surface 38a oriented towards the outside of the ring and an internal peripheral surface 38b oriented towards the inside of the ring. The ring 38 also comprises a pin or finger 38c which extends radially from the external peripheral surface 38a away from the latter, that is to say in a radial direction taken relative to the longitudinal axis XX' around which the ring 38 is mounted in the position shown in [Fig. 2].

[0025] The ring 38 shown in [Fig.3] is symmetrical with respect to a median axial plane containing the axis XX' and which here passes through the middle of the pin 38c.

[0026] The annular ring 38 is in the form of a split ring, elastically deformable, which is provided with two free ends 38d and 38 spaced from each other along a circumference of the ring.

[0027] Each of the two free ends 38d and 38e forms a return oriented radially towards the inside of the annular ring and which constitutes a gripping / actuating member for a user / tool, allowing the latter to bring these two free ends closer to each other, by elastic deformation of the ring, with a view to mounting it inside the sheath. These free ends are also used for dismantling the ring.

[0028] It will be noted that the ring 38 extends over an angular range of less than 360°, for example of the order of 355°, in order to provide a free space E between the two free ends 38d and 38e. The minimum value of angular extension of the ring is the order of 255° so that it can fit in a groove of the sheath. Generally speaking, the angular range chosen for the ring is there for the self-maintenance of the ring in the groove and to ensure self-balancing with a center of gravity close to the center in order to avoid balancing problems.

[0029] As shown in [Fig. 2], the protective sheath 36 comprises a substantially annular wall which extends axially concentrically surrounding the shaft 34. More particularly, the protective sheath 36 comprises locally, at a location where the sheath is in contact with the journal 32, a zone Zi of the annular wall which is arranged radially internally (i.e. closer to the axis XX') relative to a radially external zone Ze (further from the axis XX') of the annular wall of the journal 32 which surrounds it. The radially internal zone Zi of the annular wall is pierced with a plurality of holes 36a distributed circumferentially and each passing through the annular wall in a radial direction (over its entire thickness), as shown in FIGS. 2 and 4.

[0030] The radially external zone Ze of the annular wall of the journal 32 comprises, for its part, a plurality of housings 32a, here grooves, distributed circumferentially and each extending in an annular groove of the journal in a radial direction (figs. 2 and 4).

[0031] The annular ring 38 is mounted coaxially inside the radially internal zone Zi of the annular wall of the protective sheath 36 (thanks to its flexibility as explained above by pinching the two ends 38d-e so as to give the ring a diameter smaller than its installation diameter), in such a way that the pin 38c can engage radially both in one of the radial holes 36a of the protective sheath and in one of the housings 32a opposite the radially external zone Ze of the journal 32 (the pin engages in the first holes and housings which align). [Fig. 2] illustrates this engagement position, as does the partial perspective view of the interior of the sheath in [Fig. 5]. The annular ring 38 thus mounted and engaged forms a system for locking the protective sheath 36 against rotation relative to the journal 32 which is itself fixed to the disc 30.During assembly it is necessary to rotate the sheath, after tightening the sheath (upstream screwing) to the required torque (without exceeding the maximum torque imposed).

[0032] The housings 32a of the journal 32 being here grooves ([Fig.2]), they only allow a single degree of freedom along the axis XX'. This arrangement is useful for taking into account an axial movement due to the differential expansion between the journal and the sleeve.

[0033] It will be noted that the configuration of the ring ring 38 allows it to be mounted at a distance from the ends of the sheath 36 and, as shown in [Fig. 2], at a distance from the downstream end 36b which, here, carries cantilevered wipers 36c. The presence of the wipers would in fact make it impossible to mount, at this end, a conventional system for locking the protection sheath 36 in rotation. Generally speaking, access to the downstream zone Za illustrated in [Fig. 2] to set up such a conventional system is not possible without impacting and calling into question the entire configuration of this zone. As shown in [Fig. 2], the journal 32 is mounted in rotation in a casing 33 of the turbomachine (partially shown in the figure) by means of one or more bearings 35 located downstream of the ring 38. The bearing(s) 35 are mounted on the turbine side of the turbomachine. The wipers 36c are thus configured to provide sealing both radially under the bearing(s) 35 and axially in the vicinity of this or these bearings.

[0034] Furthermore, the radially internal zone Zi of the annular wall of the protective sheath 36 can be shaped locally so as to form an axial stop against which the annular ring 38 bears, here by its upstream lateral surface perpendicular to the external 38a and internal 38b peripheral surfaces. Thus, in Figures 2 and 5, the local shaping takes the form of an internal wall or shoulder 36d located upstream of the position where the radial holes 36a of the protective sheath are arranged, here in a radially flared part of the sheath. This arrangement makes it possible to prevent the annular ring from rotating relative to the pin 38c.

[0035] As shown in Figures 6A-D, the pin 38c can take different shapes other than the cylindrical shape shown in the previous figures and in the partial enlarged view of [Fig.6A].

[0036] As an example, the pin has a section taken in a plane perpendicular to the radial direction of extension of the pin which has a shape chosen from the following shapes: circle ([Fig.6A]), rectangle 38cl ([Fig.6B]), oblong shape 38c2 ([Fig.6C]), oblong shape with flat(s) 38c3 ([Fig.6D]), ellipse...

[0037] The rod 38 generally allows a temperature of up to 500°C to be maintained and does not disturb the ventilation of the downstream zone Za. The rod 38 can, for example, be made of Inconel 718.

[0038] Although the present description refers to specific exemplary embodiments, modifications may be made to these examples without departing from the general scope of the invention as defined by the claims. Furthermore, individual features of the various embodiments illustrated or mentioned may be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

Claims

1. Aircraft turbomachine comprising: - a journal (32) secured to a rotor disc (30) of a turbine of the turbomachine which is configured to rotate about a longitudinal axis (XX') of the turbomachine, - a sleeve (36) of a rotor shaft (34) of the turbomachine extending axially inside the sleeve, the journal (32) being arranged coaxially around the sleeve (36), - a system for locking the sleeve (36) in rotation, characterized in that the sleeve (36) comprises an annular wall which is radially internal relative to a radially external annular wall of the journal (32) which surrounds it, the annular wall of the sleeve (36) being pierced with a plurality of holes (36a) distributed circumferentially and each passing through the annular wall of the sleeve (36) in a radial direction,the annular wall of the journal (32) comprising a plurality of housings (32a) distributed circumferentially and each arranged in the journal (32) in a radial direction, the rotation locking system of the sheath (36) comprising a snap ring (38) which is in the form of a split ring provided with a pin (38c) extending radially from a radially external surface (38a) of the split ring, the snap ring (38) being mounted coaxially inside the annular wall of the sheath (36) in such a way that the pin (38c) is engaged radially both in one of the radial holes (36a) of the annular wall of the sheath (36) and in one of the housings (32a) opposite the annular wall of the journal (32).,

2. Turbomachine according to claim 1, characterized in that the annular wall of the sheath (36) forms an axial stop (36d) against which the ring (38) bears.

3. Turbomachine according to claim 1 or 2, characterized in that the ring (38) is an elastically deformable split ring which is provided with two free ends (38d-e) allowing its mounting inside the annular wall of the sheath (36) by bringing its free ends together.

4. Turbomachine according to claim 3, characterized in that each free end (38d-e) of the ring (38) forms a return oriented radially towards the inside of the ring (38).

5. Turbomachine according to one of claims 1 to 4, characterized in that that the pin (38c) has a section taken in a plane perpendicular to the radial direction of extension of the pin (38c) which has a shape chosen from the following shapes: circle, rectangle, oblong shape, oblong shape with flat(s), ellipse.

6. Turbomachine according to one of claims 1 to 5, characterized in that the annular wall of the sleeve (36) is arranged at a distance from the two opposite ends (36b) of the sleeve (36).

7. Turbomachine according to claim 6, characterized in that the sheath (36) carries at one of its two opposite ends wipers (36c).

8. Turbomachine according to one of claims 1 to 7, characterized in that the journal (32) is mounted in rotation in a casing of the turbomachine by means of at least one bearing located downstream of the ring (38).

9. Turbomachine according to claim 8, characterized in that said at least one bearing is mounted on the turbine side of the turbomachine.

10. Turbomachine according to claim 7 and claim 8 or 9, characterized in that the wipers provide a seal radially under said at least one bearing and axially in the vicinity of the latter.

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