FR3063309A1 - TURBOMACHINE ROTATING INLET COVER, COMPRISING AERODYNAMIC EXTERNAL WALL AND CONE CLAMP - Google Patents

Abstract

The invention relates to a rotating inlet hood for a turbomachine (1). The cover comprises a cone (3), a shell (4) and a screw (70) for fixing the cone (3) to the ferrule (4). The cone (3) comprises a housing (8) for the screw (70), which is covered by an aerodynamic outer wall (30). The housing (8) comprises an outer wall (85) which is traversed by a first orifice (81) for the insertion of the screw (70) into an internal space (31) of the housing, and by a second orifice (83). ) which is intended for the introduction of a holding member (90) of the screw. The outer wall (30) is traversed by a clamping orifice (33), the clamping orifice (33) allowing the introduction of a clamping tool into the internal space (31) to tighten the screw (70). . The diameter (17) of the clamping orifice (33) is smaller than that of a head (72) of the screw (70).

Description

(54) TURBOMACHINE ROTATING INPUT COVER, COMPRISING AERODYNAMICS AND A CONE TIGHTENING MEMBER.

A

EXTERNAL WALL

FR 3 063 309 - A1) 5 /) The invention relates to a rotary inlet cover for a turbomachine (1). The cover comprises a cone (3), a ferrule (4) and a screw (70) for fixing the cone (3) to the ferrule (4). The cone (3) includes a housing (8) for the screw (70), which is covered by an aerodynamic outer wall (30). The housing (8) comprises an external wall (85) which is crossed by a first orifice (81) intended for the introduction of the screw (70) into an internal space (31) of the housing, and by a second orifice (83 ) which is intended for the introduction of a holding member (90) of the screw. The outer wall (30) is crossed by a tightening hole (33), the tightening hole (33) allowing the introduction of a tightening tool into the internal space (31) to tighten the screw (70) . The diameter (l ₇ ) of the clamping orifice (33) is less than that of a head (72) of the screw (70).

TURBOMACHINE ROTATING INPUT COVER, INCLUDING AN AERODYNAMIC EXTERNAL WALL AND A CONE TIGHTENING MEMBER

DESCRIPTION

TECHNICAL AREA

The invention relates to the general technical field of aircraft turbomachines such as turbojets and turbopropellers. More specifically, the invention relates to a rotating inlet cone for a turbomachine.

PRIOR STATE OF THE ART

Blowers for turbomachines include a rotating inlet hood. The cover includes a cone and a ferrule located downstream of the cone to which the cone is fixed.

The cone includes an outer wall having an aerodynamic outer surface, and an inner wall extending downstream. The screws securing the cone to the ferrule tend to disturb the flow of air along the inlet cover.

Some covers include plugs spaced from each other in a circumferential direction of the cone. These plugs are intended to cover the screws securing the cone to the shell, to improve the aerodynamics of the rotating cover.

However, these plugs are often difficult to fix to the cone, they make the fastening or detachment of the cone to the ferrule tedious, and / or the air circulating along the hood remains aerodynamically highly disturbed.

STATEMENT OF THE INVENTION

The invention aims to at least partially solve the problems encountered in the solutions of the prior art.

In this regard, the invention relates to a rotating inlet cover for a turbomachine. The cover has an axis of rotation. The cover comprises a cone, a ferrule located downstream of the cone, and a screw for fixing the cone to the ferrule.

The cone defines an upstream end of the inlet cover. The cone includes an outer wall having an aerodynamic outer surface. The cone is configured to be fixed to the ferrule. The cone includes a housing for the screw.

The housing includes an outer wall projecting inwardly from the cone from the outer wall of the cone.

According to the invention, the housing is covered by the outer wall, the outer wall defining an inner space. The cover includes a holding member configured to hold the screw in the internal space.

The external wall is traversed by a first orifice oriented in a first direction and intended for the introduction of the screw into the internal space. The outer wall is traversed by a second orifice oriented in a second direction inclined relative to the first direction, the second orifice being intended for the introduction of the holding member into the internal space.

The external wall is crossed by a tightening hole, the tightening hole allowing the introduction of a tightening tool in the internal space to tighten the screw in the first direction and fix the cone to the ferrule. The diameter of the clamping hole is less than that of a screw head.

The holding member comprises a base intended to cover at least partially the first orifice and traversed by a through hole for the passage of the screw. The holding member comprises a support portion configured to be supported on the external wall inside the housing to retain the screw in the first direction.

Thanks to the invention, the inlet cover is devoid of plugs. Securing and / or detaching the cone from the shell becomes easier. The caps are not likely to be forgotten when the cone is joined to the ferrule. The outer wall covers the housing of the cone fixing screw, which eliminates the problems of securing a plug and limits aerodynamic disturbances at the level of the cone fixing screws. The cone fixing screw is intended to be inserted in the housing where it is held by the holding member, before the cone comes to bear against the ferrule and is fixed to the ferrule.

The invention may optionally include one or more of the following characteristics, whether or not combined.

Advantageously, the cover comprises a screw for fixing the shell to a downstream part of the fan which is spaced radially from the screw for fixing the cone towards the inside of the cover relative to the axis of rotation of the cover.

Preferably, the ferrule fixing screw extends parallel to the axis of rotation of the cover.

According to a particular embodiment, the clamping orifice and the first orifice are oriented substantially radially with respect to the axis of rotation of the cone.

As a variant, the clamping orifice and the first orifice are oriented substantially parallel to the axis of rotation of the cone.

According to an advantageous embodiment, the external wall of the housing comprises a first wall element crossed by the first orifice. The external wall comprises a second wall element through which the second orifice passes, the second wall element being connected to the first wall element by an edge or a chamfer.

According to another particular feature, the external wall of the housing comprises at least four faces interconnected by edges and / or chamfers,

Preferably, the external wall comprises a general form of polyhedron with a trapezoidal base, and preferably a general parallelepiped shape.

Advantageously, the internal space comprises an internal conduit which extends in the first direction and a lateral cavity which extends in the second direction. The lateral cavity opens into the internal duct and has a greater width in the second direction than the width of the internal duct in the second direction.

The first orifice opens into the internal conduit and the second orifice opens into the lateral cavity. The internal conduit is intended to receive the screw and the lateral cavity is intended to receive the holding member.

According to a particular embodiment, the inlet cover comprises a member for retaining the screw inside the internal space in the first direction, as long as the screw is not secured to the ferrule.

Preferably, the retention member comprises a base traversed by a central hole and retention fingers projecting from the base and intended to surround the screw.

According to an advantageous embodiment, the inlet cover comprises a stop member configured to retain the holding member in the internal space, by preventing the holding member from leaving the internal space through the second orifice and / or through the first opening.

Preferably, the stop member comprises an elastic ring which bears against the external wall in the internal space.

Advantageously, the inlet cover comprises a support member intended to be inserted into the first orifice and configured to cooperate with the screw to facilitate the extraction of the screw from the first orifice to the internal space.

Preferably, the support member comprises a ring through which a through hole passes for the passage of the cone fixing screw.

The invention also relates to a method of fixing a cone to a ferrule of a cover as defined above.

The fixing method comprises the introduction of the cone fixing screw into the internal space through the first opening, and the introduction of the holding member through the second opening to retain the screw in the internal space according to the first direction. The method comprises the screwing of the cone fixing screw in the first direction by a clamping tool which is introduced into the internal space through the clamping orifice, to fix the cone to the ferrule.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood on reading the description of exemplary embodiments, given for purely indicative and in no way limiting, with reference to the appended drawings in which:

Figure 1 is a partial schematic perspective view of a fan for a turbomachine, comprising a cover according to a first embodiment of the invention;

Figure 2 is a partial schematic representation in longitudinal section of the cover according to the first embodiment;

Figures 3 and 4 are partial schematic representations in perspective of the hood cone according to the first embodiment;

Figure 5 is a perspective representation of the cover retaining ring according to the first embodiment;

Figure 6 is a perspective representation of the cover holding member according to the first embodiment;

Figure 7 is a perspective representation of the hood support ring according to the first embodiment;

Figure 8 is a partial schematic representation in longitudinal section of a cover according to a second embodiment;

Figures 9 and 10 are partial schematic representations in perspective of the cone according to the second embodiment.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

Identical, similar or equivalent parts of the different figures have the same reference numerals so as to facilitate the passage from one figure to another.

FIG. 1 represents a fan 2 for an aircraft turbomachine 1. The turbomachine 1 is a turbojet engine which has a shape of revolution around a longitudinal axis X-X of the turbomachine. The turbomachine 1 is double flow and double body.

The fan 2 comprises a cone 3 defining an upstream end of the fan 2, an upstream ferrule 4 situated downstream of the cone 3, and a disc 5 situated downstream of the ferrule 4 and which carries movable blades 50 at its outer surface. The disc 5 is part of a downstream part of the fan 2. The cone 3 is fixed to the shell 4 by a system for attaching the cone. The ferrule 4 is fixed to the disc 5 by a system for attaching the ferrule.

The upstream and downstream directions are used in this document with reference to the overall flow of gases in the turbomachine 1, such a direction is also qualified as axial. A radial direction is a direction substantially orthogonal to the axis of the turbomachine X-X and intersecting this axis. The terms front and rear are used respectively as synonyms of upstream and downstream respectively.

With joint reference to FIGS. 1 and 2, the cone 3 and the ferrule 4 jointly form a rotating inlet cover of the fan 2. The inlet cover comprises the system for attaching the cone.

The inlet cowl is configured to rotate around the longitudinal axis XX of the turbomachine, being integral in rotation with the disc 5. It has an aerodynamic continuous outer surface Si, S ₃ . This aerodynamic surface extends, from upstream to downstream, from the cone 3 to the ferrule 4. The aerodynamic outer surface Si, S ₃ of the cover is of generally frustoconical shape.

The ferrule 4 comprises an axial wall 42, a radial wall 40 connected to the axial wall 42, and a downstream wall 44 connected to the radial wall 40 and which extends downstream relative to the radial wall 40. The wall axial 42, the radial wall 40 and the downstream wall 44 form a one-piece wall.

The axial wall 42 projects from the radial wall 40 upstream of the radial wall 40, in an axial direction which is substantially parallel to the direction of the axis of rotation X-X of the cover. The axial wall 42 is intended to serve as centering for a first wall element 82 of the cone. It is crossed by a through hole 45 oriented radially, for the passage of a rod 74 of fixing screw 70 of the cone to the ferrule.

The radial wall 40 extends in a radial direction which is substantially orthogonal to the direction of the axis of rotation X-X of the cover. The ferrule 4 is connected to the disc 5 by the attachment system of the ferrule at the level of the radial wall 40, near a radially lower end of the radial wall 40. The radial wall 40 is configured to act as a support plan to a second wall element 84 of the cone. The ferrule 4 is also intended to be connected to the cone 3 at the level of the radial wall 40 by the system for attaching the cone.

The downstream wall 44 projects from the radial wall 40 radially outward and axially downstream. The downstream wall 44 partially covers the disc 5. It has an aerodynamic outer surface S ₃ of frustoconical shape.

The attachment system of the ferrule comprises a plurality of attachment 6 which are angularly distributed around the axis of rotation X-X of the cover. The fasteners 6 are angularly spaced substantially uniformly from each other along a circumferential direction of the cone. The fasteners 6 extend substantially parallel to the axis of rotation X-X of the cover.

Each fastener 6 comprises a fixing screw 60 and a nut 61. The screw 60 cooperates with the nut 61. The screws 60 each comprise a head 62 and a rod 64 which is in one piece with the head 62. Each rod 64 extends through the radial wall 40 and through the disc 5 axially in a direction ZZ. The nuts 61 are each in abutment against the disc 5 and the heads 62 of the fixing screws 60 are each in abutment on the radial wall 40.

With more specific reference to FIG. 2, the cone 3 comprises an outer wall 30 and housings 8 for screws 70 for fixing the cone. Each housing 8 comprises an external wall 85 which delimits it externally. The external wall 85 internally delimits an internal space 31 of the housing 8.

The outer wall 30 and the outer wall 85 of each housing 8 form a one-piece wall.

The outer wall 30 includes a front segment 30a and a rear segment 30b. The front segment 30a defines an upstream end of the cone. The rear segment 30b extends downstream of each housing 8.

The outer wall 30 has an aerodynamic outer surface Si. The outer surface Si has a generally frustoconical shape. It is located in the extension and in aerodynamic continuity of the outer surface S ₃ of the shell. The external wall 30 comprises an internal surface S ₂ which is substantially annular and from which extends the external wall 85 of each housing 8.

The outer wall 30 covers each housing 8. It is traversed by a plurality of clamping orifices 33 which are each located between the front segment 30a and the rear segment 30b.

Each clamping orifice 33 crosses the outer wall 30 and extends radially in a first direction Υχ-Υι, opening into the internal space 31 of the corresponding housing. The clamping orifices 33 are spaced angularly uniformly from one another, being opposite each of one of the screws 70 for fixing the cone. The diameter l ₇ of each clamping orifice 33 is less than that of the head 72 of screws 70 for fixing the corresponding cone.

Each clamping orifice 33 allows the introduction of a clamping tool into the internal space 31 to tighten the screw 70 for fixing the cone in the first direction Yi-Yi.

With reference to FIGS. 2 to 4, the external wall 85 of each housing 8 projects radially inwards from the cone 3 from the external wall 30 of the cone. The external wall 85 comprises a base 80 which extends radially inwards from the cone 3 from the internal surface S ₂ of the external wall 30, and a head 8a which is located at a distal end of the housing 8.

The head 8a comprises at least five wall elements 82, 84, 86, 88 and 89 which are interconnected by edges, each forming one of the five faces of the head 8a. The wall elements 82, 84, 86, 88 and 89 are two by two orthogonal. They jointly form a head 8a which is of generally parallelepiped shape.

The first wall element 82 extends axially. It defines the lower end of the housing 8 in the first direction Yi-Yi. It is crossed by a first orifice 81 which opens onto the outside of the housing 8.

The first orifice 81 extends radially in the first direction Y _x Yi, being aligned with the clamping orifice 33. The first orifice 81 is intended for the introduction of the screw 70 into the internal space 31 of the housing, before the screw 70 is tightened from the tightening hole 33.

The second wall element 84 extends radially. It is connected to the first wall element 82 by a chamfer 82a. It is crossed by the second orifice 83 which opens onto the outside of the housing 8. The second orifice 83 is oriented in a second direction Y ₃ -Y ₃ which is inclined relative to the first direction Yi-Yi.

The second direction Y ₃ -Y ₃ is substantially orthogonal to the first direction Yi-Yi. The second direction Y ₃ -Y ₃ is substantially parallel to the axis of rotation XX of the cone.

The second orifice 83 is intended to be opposite the radial wall 40, when the cone 3 is fixed to the ferrule 4. The second orifice 83 is intended for the introduction into the internal space 31 of a wedge 90 (better visible in FIG. 6) configured to limit the displacement of the fixing screw 70 of the cone in the first direction Yi-Yi relative to the first orifice 81.

The internal space 31 includes an internal conduit 32 and a lateral cavity 37.

The internal duct 32 extends in the first direction Yi-Yi which corresponds to the longitudinal direction of the housing 8. It opens onto the outside of the cone in the first direction Yi-Yi through the first orifice 81 on the one hand and through the clamping orifice 33 on the other hand. The lower portion of the internal duct 32 in the first direction Yi-Yi is part of the lateral cavity 37.

The internal conduit 32 has a length Li in the first direction Yi-Yi which is slightly less than the total length of the housing in this direction. The internal conduit 32 has a width h in the second direction Y ₃ -Y ₃ which is strictly less than its length Li and which is slightly greater than the sum of the width of the head 72 of the screw 70 for fixing the cone and the thickness of a retention ring 10 which will be described below. The internal conduit 32 is intended to receive the fixing screw 70.

The lateral cavity 37 extends in the second direction Y ₃ -Y ₃ . It opens on the one hand on the outside of the cone through the second orifice 83 and on the other hand into the internal duct 32. The lateral cavity 37 extends in the lower portion of the internal duct 32 in the first direction Yi- Yi.

The lateral cavity 37 has a length l ₃ in the first direction Yi-Yi which corresponds to the length of the lower portion of the internal conduit 32. It has a width l ₂ in the second direction Y ₃ -Y ₃ which is strictly greater than its length l ₃ in the first direction Yi-Yi. The width l ₂ of the lateral cavity 37 is greater than the width h of the internal duct 32.

The lateral cavity 37 is intended to receive the wedge 90.

The system for attaching the cone to the shell comprises a plurality of fixing members 7 and a plurality of retaining members 9 which are intended to retain the screws 70 of each fixing member 7 in their respective housings 8.

The fastening members 7 are angularly spaced from one another around the axis of rotation X-X of the cover. They are angularly spaced substantially uniformly from each other along a circumferential direction of the cone. The fixing members 7 extend substantially radially.

Each fixing member 7 comprises a fixing screw 70 and a nut 71. The screw 70 cooperates with the nut 71. The screws 70 each comprise a head 72 and a rod 74 which is in one piece with the head 72. Each rod 74 s 'extends through the first wall element 82 and through the axial wall 42 radially in the first direction Yi-Yi. More specifically, each rod 74 extends successively through a retention ring 10, a wedge 90, a support ring 94 and the nut 71 in the first direction Yi-Yi. The nuts 71 are each in abutment against a lower surface of the axial wall 42.

The retaining members 9 of the screws 70 each comprise a shim 90, a retention ring 10, an elastic ring 92 and a support ring 94 (FIGS. 5 to 7).

With reference to FIGS. 2 and 5, the retention ring 10 of each retention member 9 comprises a base 100 and a plurality of retention fingers 102 which project radially from the base 100.

The base 100 is annular around its longitudinal direction which coincides with the first direction Yi-Yi, when the retention ring 101 is mounted in the internal space 31. It is crossed in its center by a central hole 101 through which the rod 74 of the fixing screw 70 is intended to extend in the first direction Yi-Υχ. The central hole 101 of the retention ring 10 is threaded to cooperate with the rod 74 of the cone fixing screw.

There are three retention fingers 102. They each extend from the base 100 to their distal end 102a which is curved towards the central hole 101, to form stops for the head 72 of screws in the first direction Yi-Yi.

The retention ring 10 is configured to retain the screw 70 relative to the housing 8 in the first direction Yi-Yi, between an extreme tightening position which is shown in FIG. 2 and an extreme loosening position (not shown).

In the extreme tightening position, the head 72 of the screw is surrounded by the base 100. The head 72 of the screw is retained by the base 100 in the first direction Yi-Yi, towards the first orifice 81.

In the extreme loosening position, the distal ends 102a of the fingers form a stop for the screw head 72 in the first direction Yi-Yi towards the clamping orifice 33.

The distal ends 102a thus prevent the rod 74 of the screw from completely disengaging from the central hole 101 of the retention ring 10, and from being misaligned with the direction Yi-Yi, which would prevent its tightening.

The retention ring 10 forms a retention member 10 of the screw 70 inside the internal space 31 in the first direction Yi-Yi, as long as the screw 70 is not secured to the ferrule 4. The ring retention 10 allows to retain the screw 70 with its rod 74 aligned in the first direction Yi-Yi, when the screw 70 moves relative to the retention ring 10 between the extreme loosening position and the extreme tightening position.

With reference to FIGS. 2 and 6, the shim 90 of each retaining member 9 comprises a base 96 and a support portion 98.

The base 96 has the shape of a truncated cylinder. It extends longitudinally substantially in the second direction Y ₃ -Y ₃ when the wedge 90 is housed in the lateral cavity 37. It is intended to bear on the first wall element 82 inside the lateral cavity 37, by partially covering the first orifice 81.

The base 96 is traversed in the first direction Yi-Yi by a through hole 97 for the passage of the screw 70. The through hole 97 is intended to be aligned with the central hole 101 of the retention ring 10, when the ring retention 10 and the fixing screw 70 are supported on the base 96.

The base 96 comprises a flat upper surface S ₄ on which the retention ring 10 is intended to come to bear and which is traversed by the through hole 97.

The base 96 is delimited in the second direction Y ₃ -Y ₃ on the one hand by the support portion 98 and on the other hand by an upstream flank 99 which is substantially orthogonal to the upper surface S ₄ . The upstream flank 99 has the shape of a half disc.

The bearing portion 98 forms a downstream edge of the wedge 90. It has a substantially annular shape around an axis which is substantially orthogonal to a longitudinal direction of the base 96, that is to say around the second direction Y ₃ -Y ₃ . In other words, the support portion 98 extends substantially orthogonally to the base 96, in the first direction Υχ-Υχ.

The support portion 98 has a lower end which is intended to bear on the first wall element 82 in the lateral cavity 37. It has an upper end which is intended to bear on the second wall element 84 according to the first direction Υχ-Υχ.

The wedge 90 is intended to be introduced into the lateral cavity 37 through the second orifice 83, once the fixing screw 70 is housed in the internal duct 32 and before the cone 3 is in abutment against the ferrule 4.

The wedge 90 forms a holding member 90 of the fixing screw 70 which is configured to hold the screw 70 and the retaining ring 10 in the internal space 31 in the first direction Υχ-Υχ. It serves in particular as a stop for the head 72 of the screw and the retention ring 10 in the first direction Υχ-Υχ towards the first orifice 81.

The wedge 90 prevents the screw 70 and the retention ring 10 from leaving the internal conduit 32 through the first orifice 81, for example in the absence of the support ring 94.

The retaining member 9 comprises an elastic ring 92 which is made of elastic material. The elastic ring 92 is designed to be supported inside an annular groove of the orifice 83. The elastic ring 92 is annular around the second direction Y ₃ -Y ₃ .

The elastic ring 92 is intended to come into abutment against the downstream surface of the support portion 98 to retain the wedge 90 in the lateral cavity 37 in the second direction Y ₃ -Y ₃ , preventing the wedge 90 from coming out of the housing 8 inadvertently through the second orifice 83. The elastic ring 92 then plays the role of a stop member of the wedge 90 in the second direction Y ₃ -Y ₃ downstream.

The retaining member 9 comprises a support ring 94 which is intended to be inserted into the first orifice 81, by partially closing the first orifice 81.

The support ring 94 comprises a base 110 and a flange 112 which projects radially from the base 110.

The base 110 is of non-circular shape, for example square. It thus avoids rotation of the support ring 94 relative to the first orifice 81 when the fixing screw 70 is tightened in the first direction Yi-Yi.

The collar 112 has an annular shape. The base 110 and the flange 112 are crossed by a central through hole 111 which serves to pass the rod 74 of the screw 70 through the first orifice 81. The through hole 111 is threaded, to cooperate with the rod 74 of the cone fixing screw.

The support ring 94 forms a support member which is configured to cooperate with the screw 70 to facilitate the extraction of the screw 70 from the first orifice 81 towards the internal space 31. The support ring 94 makes it easier to loosen the fixing screws 60 of the ferrule, facilitating the removal of the fixing screws 70 from the cone of the first orifice 81. The support ring 94 is particularly useful when the fixing screw 70 is oriented radially and that it tends to descend in the first orifice 81 under the effect of its weight.

The method of fixing the cone 3 to the shell 4 of the rotating cover is detailed below.

First of all, the fixing screw 70 is introduced into the central hole 101 of the retention ring 10, in the longitudinal direction of the retention ring 10 until the distal ends 102a of the fingers 102 hold the head 72 of screws in this direction. The screw 70 is in the extreme loosening position relative to the retention ring 10.

Then, the assembly formed by the retention ring 10 and the fixing screw 70 is introduced into the housing 8 in the first direction Yi-Yi through the first orifice 81.

The wedge 90 is then introduced into the lateral cavity 37 through the second orifice 83 in the second direction Y ₃ -Y ₃ . The base 96 of the wedge 90 bears against the first wall element 82 on the one hand and against the base 100 of the retention element 10 on the other hand, in the first direction Yi-Yi. The support portion 98 comes to bear against the first wall element 82 on the one hand and against the second wall element 84 on the other hand, in the first direction Yi-Yi to prevent the fixing screw 70 and the ring retention 10 out of the housing 8 through the first orifice 81.

The elastic ring 92 is introduced into the lateral cavity 37 through the second orifice 83 in the second direction Y ₃ -Y ₃ , bearing against the first wall element 82 and the second wall element 84, according to the first direction Yi-Yi. It comes to bear against the support portion 98 in the second direction Y ₃ -Y ₃ , in order to stop the movement of the wedge 90 in the second direction Y ₃ -Y ₃ towards the second orifice 83.

Then, the support ring 94 is introduced into the first orifice 81 in the first direction Yi-Yi. The flange 112 then comes into interference with the hole of the orifice 81, which allows the support ring 94 to be held in the cone. The support ring 94 can be inserted into the orifice 81 until its base 110 abuts in the housing of similar shape in the orifice 81.

The cone 3 is then moved relative to the ferrule 4, to bear against the ferrule 4. The first wall element 82 is centered on the axial wall

42, the first orifice 81 being opposite the nut 71. The second wall element 84 comes to bear on the radial wall 40, the second orifice 83 being opposite the radial wall 40.

A clamping tool (not shown) is then introduced through the clamping orifice 33 in the first direction Yi-Yi, it engages the head 72 of the screw and tightens the screw in the first direction Yi-Yi. The screw 70 moves relative to the retention ring 10 from the extreme loosening position to the extreme tightening position which is shown in FIG. 2. The rod 74 engages the nut 71. The cone 3 is fixed to the ferrule 4 .

To separate the cone 3 from the ferrule 4, a tightening tool (not shown) is then introduced through the tightening orifice 33 in the first direction Y _x Yi, it engages the head 72 of the screw and loosens the screw according to the first direction Yi-Yi. The screw 70 moves relative to the retention ring 10 from the extreme tightening position to the extreme loosening position.

The cone 3 is then moved relative to the ferrule 4, being distant from the ferrule 4. The first wall element 82 is distant from the axial wall 42, to access the first orifice 81. The second wall element 84 is distant from the radial wall 40, to access the second orifice 83.

Then, the support ring 94 is removed from the first orifice 81 in the first direction Yi-Yi. The elastic ring 92 is withdrawn from the lateral cavity 37 through the second orifice 83 in the second direction Y ₃ -Y ₃ . The wedge 90 is withdrawn from the lateral cavity 37 through the second orifice 83 in the second direction Y ₃ -Y ₃ .

The assembly formed by the retention ring 10 and the fixing screw 70 is then optionally removed from the internal space 31 in the first direction Yi-Yi, through the first orifice 81.

The cover according to the second embodiment is shown in accompanying figures 8 to 10. The cover according to the second embodiment differs from that of the first embodiment mainly by the shape of the housings 8, in particular by a change in orientation of the first port 81 and second port 83 relative to those of the first embodiment. This results in a change in orientation of the fixing members 7 and of the retaining members 9.

The axial wall 42 of the ferrule 4 is intended to serve as centering for the second wall element 84 of the cone.

The radial wall 40 of the ferrule 4 is configured to serve as a planar support for the first wall element 82 of the cone. It is crossed by the through holes 45 which are oriented axially, for the passage of the rods 74 of fixing screws 70 from the cone to the ferrule.

The outer wall 30 covers each housing 8. It is traversed by a plurality of clamping orifices 33 which are each oriented in the first direction Y ₂ _Y ₂ .

In the second embodiment, the first direction Y ₂ _Y ₂ extends parallel to the direction of the axis of rotation XX of the cover, that is to say substantially axially. The second direction Y ₄ -Y ₄ remains inclined relative to the first direction Y ₂ -Y ₂ , in particular being orthogonal to the first direction Y ₂ _Y ₂ . The second direction Y ₄ -Y ₄ extends radially.

Each clamping orifice 33 opens into the internal conduit 32 of the corresponding housing. The clamping orifices 33 are spaced angularly uniformly from one another, being opposite each of one of the screws 70 for fixing the cone. The diameter l ₈ of each clamping orifice 33 is less than that of the head 72 of screws 70 for fixing the corresponding cone. Each clamping orifice 33 allows the introduction of a clamping tool into the internal space 31 for tightening the screw 70 for fixing the cone in the first direction Y ₂ _Y ₂ .

Drainage orifices 35 pass through the outer wall 30 of the cover. Each drainage orifice 35 is oriented radially in the second direction Y ₄ -Y ₄ , opening into the lateral cavity 37 of the corresponding housing.

The drainage orifices 35 are spaced angularly uniformly from one another, being opposite each of one of the heads 72 of the cone fixing screw. Each drainage orifice 35 makes it possible to drain the impurities and / or the liquid which would have been introduced into the internal space 31 of the corresponding housing 8.

With reference to FIGS. 8 to 10, the external wall 85 of each housing 8 projects towards the inside of the cone 3 from the external wall 30 of the cone. The external wall 85 comprises a base 80 which extends radially inwards from the cone 3 from the internal surface S ₂ of the external wall 30, and a head 8a which is located at a distal end of the housing 8.

The head 8a comprises at least four wall elements 82, 84, 86, 88 which are interconnected by edges each forming one of the four faces of the head 8a. The wall elements 82, 84, 86 and 88 are inclined relative to each other. The head 8a has a general shape of polyhedron with a trapezoidal base.

The first wall element 82 extends radially. It defines the downstream end of the housing 8 in the first direction Y2-Y2 · It is crossed by the first orifice 81 which opens onto the outside of the housing 8.

The first orifice 81 extends axially in the first direction Y ₂ Y ₂ , being aligned with the clamping orifice 33.

The second wall element 84 extends axially. It is connected to the first wall element 82 by a chamfer 82a. It is crossed by the second orifice 83 which opens onto the outside of the housing 8, being oriented radially in the second direction Y4-Y4.

The second orifice 83 is intended to be opposite the axial wall 42, when the cone 3 is fixed to the ferrule 4. The second orifice 83 is intended for the introduction into the internal space 31 of the wedge 90 configured to limit the displacement of the fixing screw 70 of the cone in the first direction Y ₂ -Y ₂ relative to the first orifice 81.

The internal space 31 includes the internal conduit 32 and the lateral cavity 37.

The internal conduit 32 extends in the first direction Y ₂ -Y ₂ which corresponds to the longitudinal direction of the housing 8. It opens onto the outside of the cone in the first direction Y ₂ -Y ₂ through the first orifice 81 d on the one hand and through the clamping orifice 33 on the other hand. The downstream portion of the internal conduit 32 in the first direction Y ₂ -Y2 forms part of the lateral cavity 37.

The internal conduit 32 has a length L ₂ in the first direction Y2-Y2 which is slightly less than the total length of the housing in this direction. The internal conduit 32 has a width l ₄ in the second direction Y ₄ -Y ₄ which is strictly less than its length L ₂ and which is slightly greater than the sum of the width of the head 72 of the screw 70 for fixing the cone and the thickness of the retention ring 10.

The lateral cavity 37 extends in the second direction Y4-Y4. It opens on the one hand on the outside of the cone through the second orifice 83 and on the other hand into the internal duct 32. The lateral cavity 37 extends in the downstream portion of the internal duct 32 in the first direction Y ₂ -Y ₂ .

The lateral cavity 37 has a length l ₆ in the first direction Y2-Y2 which corresponds to the length of the lower portion of the internal conduit 32. It has a width l ₅ in the second direction Y4-Y4 which is strictly greater than its length l ₆ along the first direction Y ₂ -Y ₂ . The width l ₅ of the lateral cavity 37 is greater than the width l ₄ of the internal conduit 32.

Each rod 74 of fixing screw 70 extends through the first wall element 82 and through the axial wall 42 radially in the first direction Y ₂ -Y ₂ . More precisely, each rod 74 extends successively through a retention ring 10, a shim 90, a support ring 94 and the nut 71 in the first direction Y ₂ -Y ₂ . The nuts 71 are each in abutment against a downstream surface of the radial wall 40.

The base 100 of each retention ring 10 is annular around its longitudinal direction which coincides with the first direction Y ₂ -Y ₂ , when the retention ring 101 is mounted in the internal space 31. It is crossed at its center by a central hole 101 through which the rod 74 of the fixing screw 70 is intended to extend in the first direction Y ₂ -Y ₂ .

The distal end 102a of the retention fingers 102 is bent towards the central hole 101, to form stops for the head 72 of the screw in the first direction Y ₂ -Y ₂ .

The retention ring 10 is configured to retain the screw 70 relative to the housing 8 in the first direction Y ₂ -Y ₂ , between the extreme tightening position which is shown in FIG. 8 and the extreme loosening position (not shown).

The base 96 of each wedge 90 extends longitudinally substantially in the second direction Y ₄ -Y ₄ when the wedge 90 is housed in the lateral cavity 37. It is intended to bear on the first wall element 82 at the inside of the lateral cavity 37, partially covering the first orifice 81.

The base 96 is traversed in the first direction Y2-Y2 by the through hole 97 for the passage of the screw 70. The through hole 97 is intended to be aligned with the central hole 101 of the retention ring 10, when the ring retention 10 and the fixing screw 70 are supported on the base 96.

The base 96 is delimited in the second direction Y ₄ -Y ₄ on the one hand by the support portion 98 and on the other hand by the upstream flank 99.

The support portion 98 is annular around an axis which is substantially orthogonal to a longitudinal direction of the base 96, that is to say around the second direction Y ₄ -Y ₄ when the wedge 90 is installed. in the lateral cavity 37. In other words, the support portion 98 extends substantially orthogonally to the base 96, in the first direction Y2-Y2 ·

The support portion 98 has a downstream end which is intended to bear on the first wall element 82 in the lateral cavity 37. It has an upstream end which is intended to bear on the second wall element 84 according to the first direction Y2-Y2 ·

The wedge 90 is intended to be introduced into the lateral cavity 37 through the second orifice 83, once the fixing screw 70 is housed in the internal duct 32 and before the cone 3 is in abutment against the ferrule 4.

The wedge 90 forms a member for holding the fixing screw 70 which is configured to hold the screw 70 and the retention ring 10 in the internal space 31 in the first direction Y2-Y2 · It serves in particular as a stop for the head 72 of the screw in the first direction Y2-Y2 towards the first orifice 81. The wedge 90 prevents the screw 70 and the retention ring 10 from coming out of the internal conduit 32 through the first orifice

81.

The elastic ring 92 is designed to bear against the second wall element 84 and against the first wall element 82, being annular around the second direction Y4-Y4.

The elastic ring 92 is intended to come to rest inside an annular groove around the axis Y4-Y4 of the orifice 83, by preventing the wedge 90 from coming out of the housing 8 inadvertently by the second orifice 83. The elastic ring 92 then acts as a stop member for the wedge 90 in the second direction Y4-Y4 radially inward.

The cover according to the second embodiment does not have a support ring 94. The fixing screws 70 extend axially, being parallel to the direction of the axis of rotation X-X. They are therefore not subjected to their weight during their movement in the first direction Y2-Y2 relative to the first orifice 81, which facilitates their tightening and / or loosening. The support ring 94 of the first embodiment is superfluous.

The method of fixing the cone 3 to the shell 4 of the rotating cover is detailed below.

First of all, the fixing screw 70 is introduced into the central hole 101 of the retention ring 10, in the longitudinal direction of the retention ring 10 until the distal ends 102a of the fingers 102 hold the head 72 of screws in this direction. The screw 70 is in the extreme loosening position relative to the retention ring 10.

Then, the assembly formed by the retention ring 10 and the fixing screw 70 is introduced into the housing 8 in the first direction Y2-Y2 through the first orifice 81.

The wedge 90 is then introduced into the lateral cavity 37 through the second orifice 83 in the second direction Y4-Y4.

The base 96 of the wedge 90 bears against the first wall element 82 on the one hand and against the base 100 of the retention element 10 on the other hand, in the first direction Y2-Y2. The support portion 98 comes to bear against the first wall element 82 on the one hand and against the second wall element 84 on the other hand, in the first direction Y ₂ -Y ₂ to prevent the fixing screw 70 and the retention ring 10 coming out of the housing 8 through the first orifice 81.

The elastic ring 92 is introduced into the lateral cavity 37 through the second orifice 83 in the second direction Y4-Y4, bearing against the first wall element 82 and the second wall element 84, in the first direction Y ₂ -Y ₂ . H comes to bear against the support portion 98 in the second direction Y4-Y4, to stop the movement of the wedge 90 in the second direction Y ₄ -Y ₄ towards the second orifice 83.

The cone 3 is then moved relative to the ferrule 4, to come to center on the ferrule 4. The first wall element 82 comes to bear on the axial wall 42, the first orifice 81 being opposite the nut 71. The second wall element 84 bears against the axial wall 42, the second orifice 83 being opposite the radial wall 40.

A clamping tool (not shown) is then introduced through the clamping orifice 33 in the first direction Y ₂ -Y ₂ , it engages the head 72 of the screw and tightens the screw in the first direction Y ₂ -Y ₂ . The screw 70 moves relative to the retention ring 10 from the extreme loosening position to the extreme tightening position which is shown in FIG. 8. The rod 74 engages the nut 71. The cone 3 is fixed to the ferrule 4 .

To separate the cone 3 from the ferrule 4, a tightening tool (not shown) is then introduced through the tightening orifice 33 in the first direction Y ₂ Y ₂ , it engages the head 72 of the screw and loosens the screw according the first direction Y ₂ -Y ₂ . The screw 70 moves relative to the retention ring 10 from the extreme tightening position to the extreme loosening position.

The cone 3 is then moved relative to the ferrule 4, being distant from the ferrule 4. The first wall element 82 is distant from the radial wall 40, to access the first orifice 81. The second wall element 84 is distant from the axial wall 42, to access the second orifice 83.

The assembly formed by the retention ring 10 and the fixing screw 70 is then optionally removed from the internal space 31 in the first direction Y ₂ -Y ₂ , through the first orifice 81.

Thanks to the invention, the outer wall 30 covers each housing 8, which eliminates the problems of securing the plug and limits the aerodynamic disturbances of the cover at the level of the fixing screws 70 of the cone. Each fixing screw 70 of the cone is intended to be inserted in its housing 8 where it is held by the wedge 90, before the cone 3 comes to bear against the ferrule 4 and is fixed to the ferrule 4.

Of course, various modifications can be made by those skilled in the art to the invention which has just been described without departing from the scope of the description of the invention.

In particular, the ferrule 4 is integrated into the disc 5, being in one piece 10 with the disc 5. In this case, the fan has no fasteners 6 from the ferrule 4 to the disc 5.

The shape of the housing 8, the orientation of the first orifice 81 and the second orifice 83, the orientation of the fixing members 7, the orientation of the retaining members 9, may vary. For example, the housings 8 can be configured to orient the fixing screws 70 at an angle of 45 ° relative to the direction of the axis of rotation X-X of the cover.

The shape and nature of the retaining member 9 may vary, in particular that of the retaining member 90, the retaining member 10, the stop member 92 and / or the support member 94. The retaining member 9 is for example devoid of the retaining member.

0 retention 10 and arresting device 92.

Claims (10)

1. Rotating inlet cover for a turbomachine (1), the cover having an axis of rotation (X-X) and comprising: a cone (3) defining an upstream end of the inlet cover, the cone (3) comprising an outer wall (30) having an aerodynamic outer surface (Si), a ferrule (4) located downstream of the cone (3), the cone (3) being configured to be fixed to the ferrule (4), a screw (70) for fixing the cone (3) to the ferrule (4), the cone (3) comprising a housing (8) for the screw (70), the housing (8) comprising an external wall (85) projecting towards the inside of the cone (3) from the external wall (30) of the cone, characterized in that the housing (8) is covered by the outer wall (30), the outer wall (85) defining an inner space (31), the cover comprising a holding member (90) configured to hold the screw (70) in the inner space (31), the outer wall (85) being traversed by a first orifice (81) oriented in a first direction (Υι-Υι, Y2-Y2) and intended for the introduction of the screw (70) into the internal space (31), the p aroi external (85) being traversed by a second orifice (83) oriented in a second direction (Y3-Y3, Y4-Y4) inclined relative to the first direction (Y1-Y1, Y2-Y2), the second orifice (83 ) being intended for the introduction of the holding member (90) into the internal space (31), the external wall (30) being traversed by a clamping orifice (33), the clamping orifice (33) allowing the introduction of a tightening tool into the internal space (31) to tighten the screw (70) in the first direction (Y1-Y1, Y2-Y2) and fix the cone (3) to the ferrule (4 ), the diameter (l ₇ , l ₈ ) of the clamping orifice (33) being less than that of a head (72) of the screw (70), the holding member (90) comprising a base ( 96) intended to cover at least partially the first orifice (81) and traversed by a through hole (97) for the passage of the screw (70), and a support portion (98) configured to be supported on the wall external (85) inside of the housing (8) for retaining the screw (70) in the first direction (Yi-Yi, Y2-Y2). 2. inlet cover according to the preceding claim, in which the cover comprises a screw (60) for fixing the ferrule to a downstream part (5) of fan which is spaced radially from the screw (70) for fixing the cone to inside the cover with respect to the axis of rotation (XX) of the cover, the screw (60) for fixing the ferrule preferably extending parallel to the axis of rotation (XX) of the cover. 3. inlet cover according to any one of the preceding claims, in which the clamping orifice (33) and the first orifice (81) are oriented substantially radially with respect to the axis of rotation (XX) of the cone, or in which the clamping orifice (33) and the first orifice (81) are oriented substantially parallel to the axis of rotation (XX) of the cone. 4. inlet cover according to any one of the preceding claims, in which the external wall (85) of the housing comprises a first wall element (82) through which the first orifice (81) passes, and a second wall element ( 84) through which the second orifice (83) passes, the second wall element (84) being connected to the first wall element (82) by an edge or a chamfer. 5. inlet hood according to the preceding claim, wherein the outer wall (85) of the housing comprises at least four faces connected to each other by edges and / or chamfers, the outer wall (85) preferably comprising a general shape polyhedron with a trapezoidal base, and preferably a general parallelepiped shape. 6. inlet hood according to any one of the preceding claims, in which the internal space (31) comprises an internal conduit (32) which extends in the first direction (Yi-Yi) and a lateral cavity (37 ) which extends in the second direction (Y ₃ -Y ₃ , Y4-Y4), which opens into the internal duct (32) and which has a width (l ₂ , I5) in the second direction greater than that ( k, l ₄ ) of the internal duct (32) in the second direction (Y3-Y3, Y4-Y4), the first orifice (81) opening into the internal duct (32) and the second orifice (83) opening into the cavity lateral (37), the internal conduit (32) being intended to receive the screw (70) and the lateral cavity (37) being intended to receive the holding member (90). 7. inlet cover according to any one of the preceding claims, comprising a member (10) for retaining the screw (70) inside the internal space (31) in the first direction (Y1-Y1, Y ₂ -Y ₂ ), as long as the screw (70) is not secured to the ferrule (4), the retention member (10) preferably comprising a base (100) through which a central hole (101) passes and retention fingers (102) projecting from the base (100) and intended to surround the screw (70). 8. Entrance cover according to any one of the preceding claims, comprising a stop member (92) configured to retain the holding member (90) in the internal space (31), preventing the member from holding (90) out of the internal space (31) through the second orifice (83) and / or through the first orifice (81), the stop member (92) preferably comprising an elastic ring which is in support against the external wall (85) in the internal space (31). 9. inlet hood according to any one of the preceding claims, comprising a support member (94) intended to be inserted into the first orifice (81) and configured to cooperate with the screw (70) to facilitate the extraction of the screw (70) from the first orifice (81) to the internal space (31), the support member (94) preferably comprising a ring through which a through hole (111) passes for the passage of the screw (70 ) fixing the cone. 10. Method for fixing a cone (3) to a ferrule (4) of a cover 5 according to any one of the preceding claims, comprising: the introduction of the screw (70) for fixing the cone in the internal space (31) through the first orifice (81), the introduction of the retaining member (90) through the second orifice (83) to retain the screw (70) in the internal space (31) in the first direction (Yi-Yi, Y2-Y2), and 10 the screwing of the screw (70) in the first direction (Y1-Y1, Y2-Y2) by a clamping tool which is introduced into the internal space (31) through the clamping orifice (33), to fix the cone (3) to the ferrule (4). S.61798 1/5