FR3108946A1 - FIXING DEVICE FOR TWO COAXIAL SHAFTS OF AN AIRCRAFT TURBOMACHINE - Google Patents

Abstract

The invention relates to a device (1) for fixing two coaxial shafts of an aircraft turbomachine, comprising: - a first tubular shaft (10) - a second tubular shaft (20) intended to receive the first shaft (10) , - a nut (30) for screwing into an internal thread (12) of the first shaft (10), - a locking ring (40) configured to be integral in rotation with said second shaft (20) and comprising first locking elements (41). According to the invention, the fixing device further comprises a locking cover (50) configured to be engaged and held axially inside said nut (30) and comprising second locking elements (51) configured to cooperate with said nut (30). first locking elements (41) for immobilizing the nut (30) in rotation with respect to said locking ring (40). Figure for the abstract: Figure 2

Description

DEVICE FOR FIXING TWO COAXIAL SHAFT OF AN AIRCRAFT TURBOMACHINE

Technical field of the invention

The invention relates to the field of lines of hollow shafts for aircraft turbomachines, and in particular to the devices for fixing the various shafts of the line.

Technical background

In the prior art, there are many solutions for assembling and securing two shafts of the same line of shafts for an aircraft turbomachine. An exemplary embodiment is for example known from document FR-A1-3 018 313. In such an assembly, elements for fixing the first and second coaxial hollow shafts cooperate with each other in order to ensure the axial and radial tightening of a first of the trees relative to a second of the trees. To ensure this maintenance, many machining operations (such as splines, for example) are carried out inside the shafts at the level of a fixing zone in order to allow the fixing elements to be secured to the shafts and to secure the shafts in them. .

However, during the manufacture of the various parts, the fastening zone is only accessible from an upstream part of one of the shafts having a significant length. This length makes access to the fixing zone difficult, which in particular complicates the performance of the various necessary machining operations mentioned above.

There is thus a need to simplify the design of the fastening elements and of the shafts constituting the line, and to make them more suitable for a complex environment offering only limited access.

The object of the present invention is in particular to solve all or part of the aforementioned problems.

The invention proposes for this purpose a device for fixing two coaxial shafts of an aircraft turbine engine, comprising:

- a first tubular shaft having a male end,

- a second tubular shaft comprising a female end intended to receive the male end of the first shaft,

- a nut for screwing into an internal thread of the male end of the first shaft, this nut comprising an external annular flange bearing on an internal cylindrical shoulder of the second shaft for the axial tightening of the male end against this shoulder, And

- A locking ring configured to be integral in rotation with said second shaft and comprising first locking elements.

According to the invention, the fastening device further comprises a locking cover configured to be engaged and held axially inside said nut, this locking cover comprising second locking elements configured to cooperate with said first locking elements to immobilize the nut in rotation vis-à-vis said locking ring.

The invention thus makes it possible, in particular thanks to the presence of the added locking ring and the mechanical collaboration between the first and second locking elements, to deport the complex machining associated in particular with the stop function of the nut. , on parts added to the shafts and therefore easily machinable, in particular the locking ring and the locking cover, rather than inside the second shaft which has a significant length, in particular upstream, and therefore little accessibility.

The fixing device according to the invention may comprise one or more of the characteristics below, taken separately with each other or in combination with each other:

• the cover comprises an external cylindrical surface comprising an annular groove for receiving an annular axial retaining ring, an external periphery of which is engaged in an annular groove of an internal cylindrical surface of the nut or of the locking ring;
• said locking ring is shrunk in said second shaft;
• said locking ring comprises an annular row of notches or teeth forming said first locking elements;
• said cover comprises an annular row of teeth or notches configured to be engaged by dog clutch in the notches or teeth of the locking ring during the engagement of the cover in said nut;
• said cover comprises external splines engaged axially in internal splines of said nut;
• said cover carries an annular seal configured to cooperate with said locking ring;
• said locking ring comprises an annular row of notches or teeth engaged in complementary teeth or notches of said second shaft;
• said locking ring includes holes or notches forming said first locking elements, said nut having similar holes or notches aligned with said holes or notches of the locking ring, and said cover having its second locking elements which are engaged both in the holes or notches of the locking element and the nut;
• said locking ring is interposed between said shoulder and said nut and carries a first annular seal resting on said shoulder, and a second annular seal resting on said nut; And
• the cover includes a central thread for screwing a tool for extracting and removing the cover by axial traction.

The invention also relates to an aircraft turbomachine, comprising a device as described above.

Brief description of figures

The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

Figure 1 is a schematic sectional view of a turbine engine according to the invention;

FIG. 2 is a perspective view of a fastening device according to the invention comprising two coaxial shafts, a nut, a ring and a cover, one of the two shafts being seen in half-section;

Figure 3 is an exploded perspective view of one of the two coaxial shafts, the nut, the ring and the cover of Figure 2;

Figure 4 is a perspective view in axial section of the nut, the ring and the cover of Figure 3;

Figure 5 is a view similar to Figure 2 showing an alternative embodiment of the invention;

Figure 6 is a view similar to Figure 5 without the cover;

Figure 7 is a perspective view of the nut, the ring and the cover;

Figure 8 is a perspective view of the cover;

FIG. 9 is a perspective view of the ring and of one of two coaxial shafts illustrated in half-section, seen from a downstream side;

FIG. 10 is a perspective view of the ring and of one of two coaxial shafts illustrated in half-section, seen from an upstream side; And

FIG. 11 is an axial sectional view of a fixing device according to the invention.

Detailed description of the invention

Referring to Figure 1, there is shown an aircraft turbine engine 100 having a longitudinal axis A around which its various components extend. The main constituents of this type of turbomachine are known from the prior art. Therefore, only a brief description will be given. Furthermore, in the present application, the axial or longitudinal direction corresponds to the direction of the longitudinal axis of rotation A. The radial direction is a direction perpendicular to the axis A and the circumferential direction is a direction perpendicular to the axial direction and in the radial direction. Furthermore, unless otherwise specified, the adjectives interior/internal and exterior/external are used in reference to a radial direction such that the interior part (i.e. radially interior) of an element is closer to the longitudinal axis A than the outer part (i.e. radially outer) of the same element. Finally, the upstream and the downstream are defined with respect to the normal flow direction of the fluid (from the upstream to the downstream) through the turbomachine, this flow direction being referenced by the arrow B in the figures.

The turbomachine 100 comprises, from upstream to downstream in the direction B, a low pressure compressor 2, a high pressure compressor 3, a combustion chamber 4, a high pressure turbine 5 and a low pressure turbine 6. The turbomachine 100 also comprises a device 1 for fixing two coaxial shafts according to the invention, here a first tubular shaft 10 connected for example to the low pressure turbine 6 and a second tubular shaft 20 connected in particular to the low pressure compressor 2.

Referring to Figures 2 to 11, the first tubular shaft 10 includes a male end 11, and the second tubular shaft 20 includes a female end 21 intended to receive the male end 11 of the first shaft 10. The male end 11 is inserted in the female end 21 on the downstream side of the second tube 20.

The fixing device 1 comprises a nut 30 for screwing into an internal thread 12 of the male end 11 of the first shaft 10. The nut 30 therefore comprises a tubular portion 34 comprising a thread 35 intended to be inserted and screwed in the thread 12 of the male end 11 of the first shaft 10. The nut 30 is thus screwed into the first shaft 10 and held axially with respect to the first shaft 10. This nut 30 comprises an external annular flange 31 bearing on an internal cylindrical shoulder 23 of the second shaft 20 for the axial tightening of the male end 11 against this shoulder 23. It is in particular a downstream face extending radially from the external annular flange 31 which comes to bear against an upstream face extending radially from the internal cylindrical shoulder 23. The first shaft 10 comprises for example an axial clamping ring 13 intended to bear against the internal cylindrical shoulder 23 of the second shaft 20, in particular on the downstream side of the shoulder internal cylindrical 23.

The ring 13 is a wedge used to adjust the axial clearance between the first shaft 10 and the second shaft 20. The axial clamping ring 13 comprises for example an annular seal 14 disposed between a wall of the clamping ring axial 13 and the internal cylindrical shoulder 23.

The fixing device 1 further comprises a locking ring 40 configured to be integral in rotation with the second shaft 20 and comprising first locking elements 41.

The fixing device 1 also comprises a locking cover 50 comprising for example a first cylindrical wall 58 extending axially around the longitudinal axis A and in particular a shoulder 59 extending radially with respect to the longitudinal axis A. The locking cover 50 is configured to be engaged and held axially inside the nut 30, in particular via its first cylindrical wall 58. The locking cover 50 comprises second locking elements 51 configured to cooperate with the first locking elements 41 to immobilize the nut 30 in rotation with respect to the locking ring 40. The locking cover 50 comprises an outer cylindrical surface 52 comprising an annular groove 53 for receiving a snap ring annular ring 54 for axial holding of cover 50 with respect to locking ring 40 and/or nut 30.

The locking cover 50 comprises a central thread 57 for screwing a tool for extracting and dismantling the locking cover 50 by axial traction. The tool is inserted on the upstream side of the second shaft 20.

Figures 2 to 4 illustrate a first embodiment of the invention. In this embodiment, the locking ring 40 is shrunk in the second shaft 20. The locking ring 40 is thus secured to the second shaft 20. The locking ring 40 here has a cylindrical wall 44 extending axially around the longitudinal axis A. It is, for example, the cylindrical wall 44 which is shrunk in the second shaft 20, in particular at the level of an outer surface of the cylindrical wall 44. The locking ring 40 comprises in particular an annular row of notches 41a or teeth forming here the first blocking elements 41. The notches 41a are for example made in the cylindrical wall 44, in particular on the upstream side of the cylindrical wall 44.

Still in the first embodiment, the locking cover 50 comprises a second cylindrical wall 60 extending axially around the longitudinal axis A. The second cylindrical wall 60 here has a larger diameter than the first cylindrical wall 58. shoulder 59 here connects the first cylindrical wall 58 to the second cylindrical wall 60. The second cylindrical wall 60 is located more upstream than the first cylindrical wall 58. The locking cover 50 further comprises an annular row of teeth 51a or d 'notches configured to be engaged by dog clutching in the notches 41a or teeth of the locking ring 40 during the engagement of the locking cover 50 in the nut 30. The collaboration between the teeth 51a of the cover 50 and the notches 41a of the locking ring thus makes it possible to secure in rotation around the longitudinal axis A, the locking cover 50 with the locking ring 40. The teeth 51a here extend radially. They originate on the second cylindrical wall 60 and project outwardly relative to this second cylindrical wall 60. The locking cover 50 also comprises external splines 62 engaged axially in internal splines 63 of the nut 30. The collaboration between the external grooves 62 of the locking cover 50 and the internal grooves 63 of the nut 30 thus makes it possible to secure in rotation around the longitudinal axis A, the locking cover 50 with the nut 30. The external grooves 62 of the lock 50 are for example arranged on the first peripheral wall 58 and protrude outwardly with respect to this first peripheral wall 58. The internal splines of the nut 30 are for example disposed on the tubular wall 34 and protrude internally with respect to this tubular wall 34.

Still according to the first embodiment of the invention, the outer cylindrical surface 52 on which the annular ring 54 is located is here located on the second cylindrical wall 60 of the locking cover. An outer periphery of the annular ring 54 is here engaged in an annular groove 43 of an internal cylindrical surface 42 of the cylindrical wall 44 of the locking ring 40. The collaboration between the annular ring 54 and the annular groove 43 makes it possible to maintain axially the locking ring 40 relative to the locking cover 50. The cover 50 here carries an annular seal 56 configured to cooperate with the locking ring 40. The seal 56 is disposed on the second wall cylindrical 60 of the locking cover 50, in particular at the level of an annular groove 61 made on the outer cylindrical surface 52 of the second cylindrical wall 60.

In this first embodiment, when the nut 30 is screwed into the first shaft 10, a downstream face of the external annular rim 31 extending radially comes to rest on an upstream face of the internal cylindrical shoulder 23. extending radially, so as to ensure the axial clamping of the male end 11 against the shoulder 23.

According to a second embodiment illustrated in Figures 5 to 11, the locking ring 40 comprises a radial circular wall 47. An opening is defined in the center of the radial circular wall 47 and is intended to receive the nut 30, in particular the tubular wall 34 of the nut 30. The locking ring 40 also comprises an annular row of notches or teeth 48. The annular row of teeth 48 projects axially with respect to the radial circular wall 47 on the downstream side of the locking ring 40. The second shaft 20 comprises teeth or notches 28 complementary to the notches or teeth 48 of the locking ring 40 so that the latter are engaged in the teeth or notches 28 of the second shaft 20. The notches or teeth 48 of the locking ring 40 and the teeth or notches 28 of the second shaft 20 are for example four in number. The teeth or notches 28 are for example made in the internal cylindrical shoulder 23 of the second shaft 20. They are machined from the downstream side of the second tube 20 whose length is much shorter than the length of the upstream side so that the Access and therefore machining on the downstream side are simpler than on the upstream side. The collaboration between the annular row of teeth 48 or notch of the locking ring 40 and the notches 28 or teeth of the second shaft 20 allows the locking ring 40 to be integral in rotation around the longitudinal axis A with the second shaft 20. The locking ring 40 comprises for example holes or notches 41b forming the first locking elements 41. The holes or notches 41b are here formed radially in the radial circular wall 47 of the locking ring 40, for example at a periphery of the radial circular wall 47.

Still according to the second embodiment, the nut 30 has holes or notches 31b aligned with the holes or notches 41b of the locking ring 40 and similar to the latter. The orifices or notches 31b of the nut 30 are in particular formed radially in the outer annular rim 31, for example at the level of a periphery of the outer annular rim 31.

In this embodiment, the second locking elements 51 of the locking cover 50 are engaged both in the holes or notches 41b of the locking element 40 and those 31b of the nut 30. The second locking elements 51 are here pins 51b (or teeth 51b) projecting for example axially downstream from the shoulder 59 of the locking cover 50. The pins are for example four in number. The pins 51b are in particular inserted axially into the notches 31b, 41b of the nut 30 and of the locking ring 40 so that the nut 30, the locking ring 40 and the locking cover 50 are integral between them in rotation around the longitudinal axis A. The pins 51b are for example located at a periphery of the locking cover 50, in particular a periphery 64 of the shoulder 59. The shoulder 59 of the locking cover 50 comprises here also a central part 65 and connecting arms 66, in particular four, connecting the central part 65 to the periphery 64.

In this embodiment, the locking ring 40 is interposed between the shoulder 23 of the second shaft 20 and the nut 30. The locking ring 40 carries for example a first annular seal 45 resting on the shoulder 23, and a second annular seal 46 resting on the nut 30, in particular on the outer annular rim 31 of the nut 30. The first annular seal 45 is for example located on a downstream face of the radial circular wall 47 of the locking ring 40. The second annular sealing gasket 46 is for example located on an upstream face of the radial circular wall 47 of the locking ring 40.

Still in the second embodiment of the invention, the outer cylindrical surface 52 on which the annular ring 54 is located is here located on the first cylindrical wall 58 of the locking cover. The outer periphery of the annular ring 54 is engaged here in an annular groove 33 of an internal cylindrical surface 32 of the nut 30.

Thus, thanks to the invention and its various embodiments, the assembly of the nut 30, the locking ring 40 and the locking cover 50 makes it possible to secure the first shaft 10 with the second shaft 20 axially and in rotation around the longitudinal axis A. This securing is done in particular by means of machining (in particular grooves, teeth and notches) made on various parts (locking ring, nut, locking cover) of the fixing device 1 which are attached inside the second shaft 20 and not directly inside the shafts.

In the examples illustrated in which the first shaft 10 is connected to the low pressure turbine and the second shaft 20 is connected to the low pressure compressor, the sealing function of the fastening device of the invention is very important because the latter is located at the level of an oil (compressor side) / air (turbine side) interface. This function is performed here by the various seals mentioned above. These seals are present in particular on the various parts (locking ring, nut, locking cover) of the fixing device 1 which are attached inside the second shaft and not directly inside the shafts, which greatly facilitates their facility.

Claims (12)

Fixing device (1) for two coaxial shafts of an aircraft turbine engine, comprising:
- a first tubular shaft (10) having a male end (11),
- a second tubular shaft (20) comprising a female end (21) intended to receive the male end (11) of the first shaft (10),
- a nut (30) for screwing into an internal thread (12) of the male end (11) of the first shaft (10), this nut (30) comprising an external annular rim (31) resting on a cylindrical shoulder (23) of the second shaft (20) for the axial tightening of the male end (11) against this shoulder (23),
- a locking ring (40) configured to be integral in rotation with said second shaft (20) and comprising first locking elements (41),
characterized in that it further comprises a locking cover (50) configured to be engaged and maintained axially inside said nut (30), this locking cover (50) comprising second locking elements (51) configured to cooperate with said first locking elements (41) to immobilize the nut (30) in rotation with respect to said locking ring (40). Device (1) according to Claim 1, in which the cover (50) comprises an outer cylindrical surface (52) comprising an annular groove (53) for receiving an annular ring (54) for axial retention, an outer periphery of which is engaged in an annular groove (33, 43) of an inner cylindrical surface (32, 42) of the nut (30) or the locking ring (40). Device (1) according to claim 1 or 2, wherein said locking ring (40) is shrunk in said second shaft (20). Device (1) according to claim 3, wherein said locking ring (40) comprises an annular row of notches (41a) or teeth forming said first locking elements (41). Device (1) according to claim 4, wherein said cover (50) comprises an annular row of teeth (51a) or notches configured to be dog-fitted in the notches (41a) or teeth of the locking ring ( 40) when the cover (50) engages in said nut (30). Device (1) according to one of Claims 3 to 5, in which the said cover (50) comprises external splines (62) engaged axially in internal splines (63) of the said nut (30). Device (1) according to one of Claims 3 to 6, in which the said cover (50) carries an annular seal (56) configured to cooperate with the said locking ring (40). Device (1) according to claim 1 or 2, wherein said locking ring (40) comprises an annular row of notches or teeth (48) engaged in complementary teeth or notches (28) of said second shaft (20). Device (1) according to claim 8, wherein said locking ring (40) comprises holes or notches (41b) forming said first locking elements (41), said nut (30) comprising holes or notches (31b) similar aligned with said holes or notches (41b) of the locking ring (40), and said cover (50) having its second locking elements (51) which are engaged both in the holes or notches (31b, 41b) the blocking element (40) and the nut (50). Device (1) according to Claim 8 or 9, in which the said locking ring (40) is interposed between the said shoulder (23) and the said nut (30) and carries a first annular seal (45) resting on the said shoulder (23), and a second annular seal (46) resting on said nut (30). Device (1) according to one of the preceding claims, in which the cover (50) comprises a central thread (57) for screwing a tool for extracting and removing the cover (50) by axial traction. Aircraft turbomachine, comprising a device (1) according to one of the preceding claims.