AIRCRAFT TURBOMACHINE INLET CONE

Abstract

The invention relates to an inlet cone (9) for an aircraft turbomachine fan mounted to rotate about an axis of rotation (R), comprising an upstream cone (1) having a vertex (S) and a downstream ferrule (2) equipped with balancing weights, the upstream cone (1) and the downstream ferrule (2) together forming the external surface of said inlet cone (9), characterized in that the inlet cone (9) further comprises a rotation-locking device (3) provided with at least one tab (31) carrying at least one rotation-locking member (33) of said upstream cone (1) adapted to engage against an underside of a first support platform (11) of said upstream cone (1), said rotation-locking device (3) of said upstream cone (1) being movably mounted between at least: an engaged position in which said at least one rotation-locking member (33) of said upstream cone (1) is engaged against said underside of said first support platform (11) of said upstream cone (1),a disengaged position in which said at least one rotation-locking member (33) is radially offset from said support platform (11) of said upstream cone (1). Figure of the abstract: Figure 4,

Description

Title of the invention: AIRCRAFT TURBOMACHINE INTAKE CONE Scope of the invention

[0001] The present invention relates to the field of turbomachinery fans, particularly for aircraft turbojet engines. More specifically, the invention concerns an inlet cone for such a turbomachine. Prior art

[0002] As illustrated in [Fig. 1], a prior art turbomachine includes at its upstream end an air inlet for supplying a blower via an airflow F. This blower comprises a blower disk 104 centered on the axis of rotation R', and blower blades 105 mounted on the blower disk 104.

[0003] The air flow F entering this turbomachine through the air inlet, in a direction corresponding to the main direction of gas flow within the turbomachine, is deflected by an inlet cone towards the fan blades 105, then is separated into a primary flow passing through the compressor supplying the combustion chamber of the turbojet and a secondary flow which flows around the compressor.

[0004] This inlet cone is centered on the axis of rotation R' and is driven in rotation with the blower disk. It can either be made in one piece as illustrated in [Fig. 5] of document EP2028375, or in several adjacent parts as illustrated in [Fig. 1] and [Fig. 2] of document EP2028375. For example, an upstream part 101 extending from the apex of the cone, otherwise called the upstream cone, and a downstream part 102, otherwise called the downstream ferrule, adjacent to the blower blades and conventionally carrying balancing weights.

[0005] In order to keep the upstream and downstream sections fixed, and these two sections on the blower disk or on a connecting piece to the blower disk, the technique currently employed consists of fixing the upstream cone to the downstream ferrule by means of a plurality of screws 106 regularly spaced around the periphery of the cone. These screws, inserted into longitudinal recesses 103, however, present a major aerodynamic drawback because the recesses are exposed and cause local turbulence that disrupts the incoming airflow.

[0006] To counter this drawback, a solution was proposed in document FR 2 908 827. According to this technique, the turbomachine inlet cone is fixed to the downstream shell by means of several screws, these screws being positioned at the level of holes made at the bottom of an annular groove formed near a downstream end. In order not to disturb the aerodynamics of the turbomachine, this groove is then covered by sealing means having an external surface aligned with that of the cone.

[0007] However, such a solution is not optimal because the different parts must be perfectly calibrated, in particular the sealing means and the orifice, so as to fit together without leaving any potential sources of disturbance to the incoming airflow.

[0008] Furthermore, a disadvantage of such a solution is that it requires a relatively large number of parts for its implementation, which generates significant complexity and cost, which is also unsatisfactory. Description of the invention

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

[0010] To this end, the invention relates to an inlet cone for an aircraft turbomachine fan mounted to rotate about an axis of rotation R, comprising an upstream cone carrying a vertex and a downstream ferrule equipped with balancing weights, the upstream cone and the downstream ferrule jointly forming the external surface of said inlet cone.

[0011] According to the invention, the inlet cone further comprises a rotation-locking device for the upstream cone, having at least one tab carrying at least one rotation-locking member for said upstream cone, capable of engaging against said lower face of a first support platform for said upstream cone, said rotation-locking device for said upstream cone being movably mounted between at least:

[0012] - an engaged position in which said at least one rotation-blocking member of said upstream cone is engaged against said lower face of a first support platform of said upstream cone, - a disengaged position in which said at least one rotation-blocking device is radially moved away from said support platform of said upstream cone.

[0013] Thus, the invention proposes a new and inventive approach making it possible to resolve at least in part some of the disadvantages of the prior art.

[0014] In particular, the invention makes it possible to keep the upstream cone fixed relative to the downstream ferrule by means positioned inside and to provide an external inlet cone surface that does not have any shape irregularities that could disrupt the flow of air entering the blower. In other words, the inlet cone obtained by the invention presented has a smooth external surface without any counterboring due to the fastening of the inlet cone elements to each other.

[0015] Furthermore, the fact that the locking device is engaged against an underside of a first support platform of said upstream cone allows the different Once assembled, the elements do not leave any potential sources of disturbance to the incoming airflow because the assembly is made possible by means implemented inside the cone.

[0016] According to one aspect of at least one embodiment of the invention, the at least one rotation-locking member of said upstream cone comprises at least one tooth, so that in the engaged position, said at least one tooth forms a ratchet against said lower face of said first ratchet-forming support platform.

[0017] Such a ratchet assembly allows that, once the upstream cone is in place against the downstream ferrule and the locking device is in the engaged position, unintentional loosening of the upstream cone relative to the downstream ferrule is prevented.

[0018] According to one aspect of at least one embodiment of the invention, said locking device is formed of a circular body from which extends a plurality of tabs arranged in a direction parallel to said axis of rotation, each of said tabs carrying at least one rotational locking member.

[0019] In this way, it is possible to distribute the blocking force of said upstream cone over the entire inner circumference of the upstream cone and thus to reduce the risks of deterioration of the locking device or breakage of the tabs.

[0020] According to one aspect of at least one embodiment of the invention, said locking device comprises at least one notch formed on said circular body, and in that said downstream ferrule has at least one tab extending radially from its inner surface, said at least one tab being configured to fit into said at least one notch so as to fix said locking device of said upstream cone against the downstream ferrule.

[0021] This allows the locking device to remain fixed relative to the downstream ferrule so that it can engage against the upstream cone and block the latter from rotating.

[0022] According to one aspect of at least one embodiment of the invention, said downstream ferrule has a second support platform. Furthermore, in said engaged position, said first support platform is sandwiched between said at least one locking member and said second support platform of said downstream vein.

[0023] This allows for the implementation of additional blocking and holding means of the upstream cone against the downstream ferrule and thus improves the blocking while limiting the forces exerted against each of the elements of the inlet cone.

[0024] According to one aspect of at least one embodiment of the invention, the first support platform further comprises an upper face, opposite said lower face, having a threaded portion configured to screw onto a thread of said second support platform provided opposite it.

[0025] As a result, the upstream cone is also held directly relative to the ferrule downstream which allows for even more blocking while limiting the forces exerted against each of the elements of the inlet cone.

[0026] According to one aspect of at least one embodiment of the invention, the first support platform further has a boss formed in the extension of said threaded portion and configured to bear against a projecting portion formed on said second support platform in the extension of said thread.

[0027] This makes it possible to limit the forces exerted against each of the elements of the inlet cone by adding a radial support.

[0028] According to one aspect of at least one embodiment of the invention, the tabs are made of a flexible material having an elasticity between 0.1 and 10 DaN / mm.

[0029] This allows the implementation of tabs with flexibility to deform, which can limit the risks of breakage, whether during assembly or disassembly of the solution.

[0030] According to one aspect of at least one embodiment of the invention, said downstream ferrule has at least one through hole formed opposite said at least one tongue.

[0031] Such a through hole can allow a tool to be passed through so as to exert radial pressure on said at least one opposite tab and thus disengage the rotation locking members of the support platform.

[0032] Such a through hole can also be used to fix the balancing weights.

[0033] The invention also relates to a turbomachine blower for aircraft mounted mobilely in rotation around an axis of rotation, the blower comprising an inlet cone according to one of the aforementioned embodiments.

[0034] According to one aspect of at least one embodiment of the blower, the transition from said engaged position to said disengaged position is achieved by rotating said inlet cone relative to said at least one locking member in a direction of rotation corresponding to the direction of rotation of said blower around the axis of rotation.

[0035] The invention also relates to an aircraft turbomachine comprising a blower according to one of the aforementioned embodiments.

[0036] According to one aspect of at least one embodiment, the turbomachine is an aircraft turbojet engine. Presentation of the figures

[0037] The invention, as well as its various advantages, will be more easily understood in the light of the following description of an illustrative and non-limiting embodiment thereof, and the accompanying drawings, among which:

[0038] [Fig-1] already described, is a schematic side view in cross-section illustrating a cone entry point of the state of the art;

[0039] [Fig.2] is a side view in cross-section schematically illustrating an inlet cone according to an embodiment of the invention, the locking device being in the engaged position;

[0040] [Fig.3] is a side view in section schematically illustrating an inlet cone according to the embodiment of [Fig.2], with an inlet cone removal tool, the locking device being in the engaged position;

[0041] [Fig.4] is a front perspective view of a locking device according to the embodiment illustrated in [Fig.2];

[0042] [Fig.5] is a rear perspective view of a locking device according to the embodiment illustrated in [Fig.2];

[0043] [Fig.6] is a schematic front view of the operation of the locking device with respect to the first support platform, and

[0044] [Fig.7] represents a schematic view of a turbofan engine, in longitudinal section. Description of the implementation methods

[0045] It should be noted that, throughout the description, the terms "upstream" and "downstream" are to be considered in relation to the main direction of gas flow within the turbomachine, and therefore to their arrival on the external surface of the inlet cone.

[0046] With reference first to [Fig. 7], an aircraft turbomachine 901 is shown, according to a preferred embodiment of the invention. This is a twin-spool, turbofan engine. However, it could be a turbomachine of another type, for example a turboprop, without departing from the scope of the invention. The turbofan engine 901 has a central longitudinal axis 902 around which its various components extend. It comprises, from upstream to downstream along a principal direction 905 of gas flow through this turbofan engine, a fan 903, a low-pressure compressor 904, a high-pressure compressor 906, a combustion chamber 911, a high-pressure turbine 907, and a low-pressure turbine 908.

[0047] Conventionally, after passing through the blower, the air splits into a central primary flow 912a and a secondary flow 912b that surrounds the primary flow. The primary flow 912a flows into a main gas circulation channel 914a, passing through the compressors 904, 906, the combustion chamber 911, and the turbines 907, 908. The secondary flow 912b flows into a secondary channel 914b, radially delimited outwards by an engine casing, surrounded by a nacelle 909. The compressors 904, 906 and the turbines 907, 908 are formed by alternating moving wheels, called rotor wheels, and fixed wheels, called stator wheels.

[0048] The principle of the invention is based on the implementation of an inlet cone comprising a rotation-locking device equipped with at least one tab carrying at least one rotation-locking element for the upstream cone and adapted to engage against the lower face of a first support platform for the upstream cone, this locking device thus making it possible to hold the upstream cone and the downstream ferrule fixed relative to each other, this locking device being mounted movably between at least:

[0049] - an engaged position in which at least one rotation-locking member of the upstream cone is engaged against the lower face of a first support platform of the upstream cone, - a disengaged position in which at least one rotation-locking device is radially moved away from the upstream cone support platform.

[0050] Such an inlet cone can for example be implemented within a fan for an aircraft turbomachine, which can in particular be an aircraft turbojet.

[0051] An embodiment of the invention is now presented in relation to figures 2 to 6, given by way of illustration and not limitation.

[0052] As illustrated in these figures, the inlet cone 9 is adapted for an aircraft turbomachine fan mounted movably to rotate about an axis of rotation R intended to be supplied by means of an airflow F.

[0053] The illustrated blower comprises a blower disk 4 centered on the axis of rotation R, and blower blades 5 attached to the blower disk 4.

[0054] This inlet cone comprises an upstream cone 1 bearing a vertex S and a downstream ferrule 2. This upstream cone 1 and this downstream ferrule 2 together form the external surface of the inlet cone 9.

[0055] It should be noted that the downstream ferrule 2 is equipped with balancing weights that can be placed regularly around its inner perimeter.

[0056] The inlet cone 9 further includes a rotation-locking device 3 for the upstream cone. This rotation-locking device is provided with at least one tab 31 carrying at least one rotation-locking member 33 for said upstream cone 1 adapted to engage against an underside face of a first support platform 11 of the upstream cone 1.

[0057] This device 3 for locking the rotation of the upstream cone 1 allows the upstream cone 1 to be locked in rotation relative to the downstream ferrule 2 and is, for this purpose, mounted movably between at least:

[0058] - an engaged position in which at least one rotation-locking member 33 of the upstream cone 1 is engaged against the lower face of the first support platform 11 of the upstream cone 1, and - a disengaged position in which at least one rotation-locking element 33 is radially moved away from the support platform 11 of the upstream cone 1.

[0059] It should be noted that, in this embodiment, the transition from the engaged position to the disengaged position is achieved by rotating the upstream cone 9 relative to at least one locking member 33 in a direction of rotation corresponding to the same direction of rotation as that of the blower around the axis of rotation R.

[0060] In other words, the direction of rotation for engaging the locking devices against the first support platform corresponds to the opposite direction of rotation of the blower, while the direction of rotation for disengaging the locking devices from the first support platform corresponds to the direction of rotation of the blower.

[0061] In the embodiment illustrated here, the locking device 3 is formed of a circular body 30 from which extends a plurality of tabs 31 which are oriented in a direction parallel to the axis of rotation R.

[0062] Preferably, these tabs 31 are distributed regularly on the circular body 30 of the locking device 3 so as to distribute the locking forces exerted uniformly on the tabs and on the circular body.

[0063] For example, it could be provided that the tabs are distributed uniformly over the circular body so that an angle between 30 and 120 degrees, for example 60, separates two tabs.

[0064] Each of these tabs 31 carries at least one rotation locking member 33 capable of engaging against an underside of the first support platform 11 of the upstream cone 1.

[0065] In the embodiment more particularly visible in [Fig.6], the rotation-locking members 33 of the upstream cone 1 comprise two teeth 33, each of the tabs therefore carrying a pair of teeth 33 which are able to engage against an inferior face of the first support platform 11 of the upstream cone 1.

[0066] According to other embodiments, tabs with a different number of teeth could be provided.

[0067] It could also be envisaged that at least one locking member has a different shape from a tooth.

[0068] Here, the first support platform 11 of the upstream cone 1 extends over the entire inner perimeter of the upstream cone so that each of the pairs of teeth carried by the tabs can engage, without prior indexing, against an underside of the first support platform 11 of the upstream cone 1.

[0069] In this way, in the engaged position, each of the pairs of teeth 33 forms a ratchet against the lower face of the first support platform 11 forming a ratchet.

[0070] In other words, in the engaged position, the ratchet and pawl mechanism formed by each pair of teeth bearing against the underside of the first support platform 11 prevents the upstream cone from rotating in the direction of rotation of disengagement and pushes it in the direction of engagement rotation.

[0071] As illustrated more particularly in [Fig. 5], the locking device 3 further comprises at least one notch 32 formed on the circular body 30, and the downstream ferrule 2 has at least one tab 20 extending radially from its inner surface. This tab 20 is configured to fit into at least one notch 32 so as to fix the locking device 3 of the upstream cone 1 against the downstream ferrule 2.

[0072] In the illustrated embodiment, the locking device 3 comprises a plurality of regularly formed notches in the periphery of the circular body 30, opening onto a downstream face of the locking device 3 and oriented in a direction parallel to the axis of rotation R. Similarly, the downstream ferrule 2 has a plurality of tabs 20 extending radially from its inner surface, each tab being configured to fit into an opposite notch 32. To this end, each tab has an end portion oriented so as to fit into the notch 32.

[0073] So that the upstream cone 1 and the downstream ferrule 2 are also directly held relative to each other, and to further limit the mechanical forces exerted on the different elements, the downstream ferrule 2 has a second support platform 22, so that, in the engaged position, the first support platform 11 is clamped between the pairs of teeth 33 and the second support platform 22 of the downstream vein 2.

[0074] In addition, and so that the upstream cone 1 and the downstream ferrule 2 are also directly held relative to each other, and to also facilitate the placement and centering of one of the two parts relative to the other, the first support platform 11 further includes an upper face, opposite the lower face, having a threaded portion 12 configured to screw onto a thread of the second support platform 22 provided opposite it.

[0075] Furthermore, and as can be seen in particular on [Fig.2], the first support platform 11 also has a boss 13 formed in the extension of the threaded portion 12 and configured to bear against a projecting portion 23 formed on the second support platform 22 in the extension of the thread.

[0076] The steps for installing the upstream cone against the downstream vein so as to jointly form the external surface of the inlet cone according to the invention are now presented.

[0077] These installation steps may be preceded by a preliminary step of mounting the rotation-locking device 3 so as to secure it against the downstream ferrule 2. Once mounted, the rotation-locking device 3 is secured against rotation and translation relative to this downstream ferrule. Furthermore, and as particularly visible in Figures 2 and 3, an axial retaining ring 34 assists in securing the rotational and translational locking device relative to the downstream ferrule.

[0078] As regards the installation method, it first includes a step of positioning the upstream cone opposite the downstream ferrule so as to be centered with respect to the axis of rotation R.

[0079] Next, the upstream cone is brought against the downstream ferrule so that the lower face of the first support platform of the upstream cone is opposite said at least one rotation-blocking member of the upstream cone.

[0080] Then, a rotation of the upstream cone in the direction of engagement is carried out so that the locking device 3 comes into the engaged position, at least one rotation-locking member of the upstream cone then being engaged against the lower face of the first support platform of the upstream cone so as to block the upstream cone in rotation relative to the downstream ferrule.

[0081] The installation steps of the upstream cone 1 against the downstream vein 2 are now presented so as to jointly form the external surface of the inlet cone according to the embodiment described in detail above.

[0082] The installation method includes a step of positioning the upstream cone 1 opposite the downstream ferrule 2 so as to be centered with respect to the axis of rotation R of the blower. The centering of the cone 1 is achieved via the boss 13 formed in the extension of the threaded portion 12 and configured to bear against the projecting portion 23 of the downstream ferrule.

[0083] The upstream cone 1 is brought against the downstream ferrule so that the threaded portion 12 is in contact with the thread of the second support platform 22.

[0084] In parallel, the lower face of the first support platform 11 of the upstream cone 1 is opposite the pairs of teeth 33.

[0085] Then, a rotation of the upstream cone in the direction of engagement is carried out so that the threaded portion screws onto the thread of the second support platform 22.

[0086] In parallel, the plurality of pairs of teeth 33 also pivots in the direction allowed by the ratchet, here the counterclockwise direction, so that the locking device 3 comes into the engaged position, the teeth 33 then being locked in rotation in the clockwise direction and the upstream cone therefore not being able to be unscrewed without external intervention.

[0087] Conversely, the upstream cone 1 must be able to be disassembled and removed from its location in the blower, for example for maintenance or cleaning operations.

[0088] To achieve this, the downstream ferrule 2 illustrated in this embodiment has a plurality of through holes 20 formed so as to be opposite said tabs 31.

[0089] These through holes can also correspond to the insertion holes of the balancing weights, or balancing screws.

[0090] In this embodiment, the disassembly first comprises a step of inserting a tool 6 into the through hole so as to exert pressure radial on the tongue. Such radial pressure allows the teeth 33 to be radially separated from the lower face of the first support platform 11 of the upstream cone 1.

[0091] In the illustrated embodiment, the tabs are made of a flexible material with an elasticity between 0.1 and 10 DaN / mm, so as to be able to exert radial pressure on the tab without risking mechanical breakage.

[0092] Next, a rotation of the upstream cone in the disengagement direction is carried out so that the threaded portion unscrews from the thread of the second support platform 22. This unscrewing is permitted because the teeth 33 are separated from the lower face of the first support platform 11 of the upstream cone 1.

[0093] It should be noted that, according to an embodiment not shown, the through hole(s) can be closed by sealing element type elements comprising a first part fixed relative to the downstream ferrule and a second part movable by pivoting relative to the first part between a closed position in which the second part closes the through hole and an open position in which the second part releases the through hole so as to allow the passage of the dismantling tool 6 through the through hole.

[0094] Preferably, such a sealing element further has return means configured to stress the second part towards the closed position, these return means being able for example to include a first arm bearing on the first part and a second arm bearing on the second part.

Claims

Demands

1. Inlet cone (9) for an aircraft turbomachine fan mounted movably to rotate about an axis of rotation (R), comprising an upstream cone (1) carrying a vertex (S) and a downstream ferrule (2) equipped with balancing weights, the upstream cone (1) and the downstream ferrule (2) jointly forming the external surface of said inlet cone (9), characterized in that the inlet cone (9) further comprises a rotation-locking device (3) provided with at least one tab (31) carrying at least one rotation-locking member (33) of said upstream cone (1) adapted to engage against an underside face of a first support platform (11) of said upstream cone (1),said rotation-locking device (3) of said upstream cone (1) being mounted movably between at least: - an engaged position in which said at least one rotation-locking member (33) of said upstream cone (1) is engaged against said lower face of said first support platform (11) of said upstream cone (1), - a disengaged position in which said at least one rotation-locking member (33) is radially away from said support platform (11) of said upstream cone (1).

2. Inlet cone (9) according to claim 1, characterized in that said at least one rotation-locking member (33) of said upstream cone (1) comprises at least one tooth (33), such that in the engaged position, said at least one tooth (33) forms a ratchet against said lower face of said first support platform (11) forming a ratchet.

3. Inlet cone (9) according to any one of claims 1 or 2, characterized in that said locking device (3) is formed of a circular body (30) from which extends a plurality of tabs (31) arranged in a direction parallel to said axis of rotation (R), each of said tabs (31) carrying at least one rotation locking member (33).

4. Inlet cone (9) according to the preceding claim, characterized in that said locking device (3) comprises at least one notch (32) formed on said circular body (30), and in that said downstream ferrule (2) has at least one tab (20) extending radially from its inner surface, said at least one tab (20) being configured to fit into said at least one notch (32) so as to fix said locking device (3) of said upstream cone against the downstream ferrule (2).

5. Inlet cone (9) according to any one of the preceding claims, characterized in that said downstream ferrule (2) has a second support platform (22), and in that, in said engaged position, said first support platform (11) is clamped between said at least one blocking member (33) and said second support platform (22) of said downstream vein (2).

6. Entry cone (9) according to claim 5, characterized in that the first support platform (11) further comprises an upper face, opposite said lower face, having a threaded portion (12) configured to screw onto a thread of said second support platform (22) provided opposite.

7. Entry cone (9) according to any one of claims 5 or 6, characterized in that said first support platform (11) further has a boss (13) formed in the extension of said threaded portion (12) and configured to bear against a projecting portion (23) formed on said second support platform (22) in the extension of said thread.

8. Inlet cone (9) according to any one of the preceding claims, characterized in that said downstream ferrule (2) has at least one through hole (20) formed opposite said at least one tongue (31).

9. Aircraft turbomachine blower mounted movably to rotate about an axis of rotation (R), characterized in that it comprises an inlet cone according to any one of claims 1 to 8.

10. Blower according to claim 9, characterized in that the transition from said engaged position to said disengaged position is made by the rotation of said upstream cone (9) relative to said at least one locking member (33) in a direction of rotation corresponding to a direction of rotation of said blower around the axis of rotation (R).

11. Aircraft turbomachine comprising a fan (9) according to any one of claims 9 or 10.

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

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