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) fixed by at least one first fixing screw (4) to a downstream ferrule (2), said first fixing screw (4) being configured to fit into a first threaded orifice (40) formed partly in said upstream cone (1) and in said downstream ferrule (2), and opening into a channel (39) machined on said upstream cone (1). According to the invention, the inlet cone (9) also comprises a cover (3) configured to fit onto said upstream cone (1) so as to close said channel (39), the upstream cone (1), the downstream ferrule (2), and said cover (3) together forming a substantially continuous external surface of said inlet cone (9). Figure 5

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, by means of an airflow F, a blower. 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, for example, be made in one piece as illustrated in [Fig. 5] of document EP2028375. It can also be made in several adjacent parts as illustrated in Figures 1 and 2 of document EP2028375, for example with 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, a known technique 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, or counterbores, 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, it may be considered to plug the counterbores by means of tapes or silicone so as to preserve the aerodynamics, for example in the context of wind tunnel tests prior to putting the turbomachine into circulation.

[0007] However, a drawback of such a solution is that the operation requires time cleaning and drying are required after each disassembly. This can also lead to a risk of damage to the inlet cone components during disassembly.

[0008] Furthermore, such a solution can only be temporary and therefore cannot reasonably be used in the context of routine use of turbomachinery.

[0009] There is therefore a need to improve current solutions in order to improve the aerodynamics of turbomachine inlet cones while avoiding the disadvantages of current solutions. Description of the invention

[0010] The invention aims to remedy at least in part the aforementioned drawbacks relating to prior art techniques.

[0011] To this end, the invention relates to an inlet cone for an aircraft turbomachine fan mounted to rotate about an axis of rotation, comprising an upstream cone fixed by at least one first fixing screw to a downstream ferrule, said first fixing screw being configured to fit into a first tapped orifice formed partly in the upstream cone and in the downstream ferrule, and opening into a groove cut on said upstream cone.

[0012] According to the invention, the inlet cone also includes a cover configured to be fixed on said upstream cone so as to close said vein, the upstream cone, the downstream ferrule and said cover together forming a continuous external surface of said inlet cone.

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

[0014] In particular, such a cover, which closes off the channel and has an outer surface continuous with the upstream cone and the downstream ferrule, limits local turbulence that could disrupt the airflow entering the turbomachine. The same applies to the first tapped orifice, which opens into a channel cut into the upstream cone. This allows the orifice to be embedded within the channel, thus preventing the creation of rising steps on the external profile of the cone that could also disrupt the airflow.

[0015] Furthermore, such a solution allows the integration of fasteners while minimizing their impact on the vein, and provides a removable system that does not require any specific intervention, whether at the time of installation (drying time, cleaning of the installation area, etc.) or for any eventual dismantling for maintenance, cleaning,

[0016] Moreover, such a solution implementing mechanically simple and easily removable components makes it possible to implement a system that is both simple to use and inexpensive.

[0017] According to a particular aspect of at least one embodiment of the invention, the cover has a through hole configured to be positioned opposite a second tapped hole formed in said vein, and adapted to cooperate with a second fixing screw so as to fix said cover on said upstream cone.

[0018] This allows for a relatively simple and inexpensive fixing of the cover, while being reliable and easily removable.

[0019] According to a particular aspect of at least one embodiment of the invention, said cover has a shape complementary to said vein.

[0020] According to a particular aspect of at least one embodiment of the invention, said cover has an oblong shape.

[0021] According to a particular aspect of at least one embodiment of the invention, said cover comprises a portion having a substantially oblong shape, extended by a platform having a second height lower than the first height, said platform being configured to come to be positioned opposite said first tapped hole.

[0022] This makes it easier to position the cover because the platform is configured to position itself opposite said first threaded hole and therefore leaves room for the head of the first fixing screw regardless of its positioning and tightening.

[0023] According to a particular aspect of at least one embodiment of the invention, the second tapped hole of the second fixing screw is centered on the first portion.

[0024] Such a solution makes it possible to implement relatively simple and inexpensive indexing means, in addition to the two portions which can also serve as indexing means.

[0025] According to a particular aspect of at least one embodiment of the invention, the second tapped orifice extends along an axis N normal to an extension direction E of said vein.

[0026] According to a particular aspect of at least one embodiment of the invention, the inlet cone further comprises sealing means provided between the periphery of said cover and the contour of said vein.

[0027] This makes it possible to further limit the circulation of air or even to allow a total seal in order to limit air disturbances.

[0028] The invention also relates to a blower for an aircraft turbomachine mounted movably in rotation around an axis of rotation R, comprising an inlet cone according to one of the aforementioned embodiments.

[0029] The invention also relates to an aircraft turbomachine comprising a blower according to the aforementioned embodiment.

[0030] According to a particular aspect of at least one embodiment of the invention, the tur-bomachine is a turbojet.

[0031] The invention is also feasible for a static cone, such as for certain testing machines. Presentation of the figures

[0032] The invention, and 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:

[0033] [Fig. 1] already described, is a schematic side view in cross-section illustrating a state-of-the-art inlet cone;

[0034] [Fig.2] represents a schematic view of a turbofan engine, in cross-section longitudinal;

[0035] [Fig.3] is a lateral cross-sectional view of a portion of the inlet cone according to a mode of realization of the invention;

[0036] [Fig.4a] is a perspective view of a portion of the entrance cone according to the mode of realization of [Fig.3];

[0037] [Fig.4b] is a front perspective view of a portion of the entrance cone along the method of implementation of [Fig.3];

[0038] [Fig.5] is an exploded perspective view of a part of the inlet cone according to the embodiment of [Fig.3], the first fixing screw being inserted;

[0039] [Fig.6] is an exploded perspective view of part of the inlet cone according to the embodiment of [Fig.3], the second fixing screw and the cover being installed;

[0040] [Fig.7] is a perspective view of a portion of the entrance cone according to the mode of rea lisation of [Fig.3];

[0041] [Fig.8a] is a front view of a part of a turbomachine according to a mode of publication of the invention, and

[0042] [Fig.8b] is a perspective view of part of a turbomachine according to the mode of the realization of [Fig.8a]. Description of the implementation methods

[0043] It should be noted that, throughout the description, the terms "upstream" and "downstream" are to be considered in terms of the main direction of gas flow within the turbomachine, and therefore at their arrival on the external surface of the inlet cone by means of the airflow.

[0044] With reference first to [Fig. 2], an aircraft turbomachine 901 is shown, according to a preferred embodiment of the invention. This is a twin-spool, turbofan engine. However, it could be a tur- a machine of another type, for example a turboprop, without departing from the scope of the invention. The turbojet 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 turbojet, a fan 903, a low-pressure compressor 904, a high-pressure compressor 906, a combustion chamber 911, a high-pressure turbine 907 and a low-pressure turbine 908.

[0045] 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.

[0046] The principle of the invention is based on the implementation of an inlet cone comprising a cover configured to close the fastening means between the upstream cone and the downstream ferrule so that the external surface of the inlet cone is substantially continuous.

[0047] Such an inlet cone can for example be implemented within a fan for an aircraft turbomachine, which can in particular be an aircraft turbojet.

[0048] A first embodiment of the invention is now presented in relation to figures 3 to 8b, given by way of simple illustrative and non-limiting example.

[0049] As illustrated, the inlet cone 9 comprises an upstream cone 1 fixed by at least one first fixing screw 4 to a downstream ferrule 2.

[0050] This first fixing screw 4 is configured to fit into a first threaded hole 40.

[0051] In this embodiment, this first tapped orifice 40 extends along an axis substantially parallel to the axis of rotation R of the aircraft turbomachine fan.

[0052] As can be seen in particular in [Fig.3], the first threaded orifice 40 is formed at least in part in the upstream cone 1 and in the downstream ferrule 2 and opens into a vein 39 cut on the upstream cone 1.

[0053] More particularly, in this embodiment, the first threaded hole 40 is drilled mostly in the downstream ferrule 2. It opens into a groove 39 cut on the upstream cone 1 so that once the first fixing screw 4 is housed in the first threaded hole 40, the screw head is mounted opening into this groove 39.

[0054] As illustrated in particular in [Fig. 3], vein 39 extends along an extension direction E. This extension direction corresponds substantially to a direction tangent to the external surface of the entrance cone 9 at the level of this vein.

[0055] So that the inlet cone 9 has a substantially continuous external surface to limit in particular the disturbances of the airflow entering the turbomachine, the inlet cone also includes a cover 3 configured to be fixed on the upstream cone 1 so as to close the vein 39.

[0056] In this way, the upstream cone 1, the downstream ferrule 2 and the cover 3 together form a substantially continuous external surface of the inlet cone 9.

[0057] In other words, the cover 3 is configured to be fixed flush in the vein 39 so that the upstream cone 1, the downstream ferrule 2 and the cover 3 together form a substantially continuous external surface of the inlet cone 9.

[0058] It should be noted that, according to an embodiment not shown here, the inlet cone may also include sealing means provided between the periphery of the cover and the inner contour of the duct so as to further limit the risks of disturbance of the aerodynamic flow and to increase the tightening of the cover against the duct.

[0059] These sealing means may, for example, include an O-ring provided on the periphery of the cover.

[0060] As can be seen more particularly in figures 6 and 7, the cover 3 here has an oblong shape.

[0061] More particularly, here, the cache 3 comprises a portion 30 having a substantially oblong shape, extended by a platform 31 having a second height h2 lower than the first height hl.

[0062] In other words, the cover 3 has a total volume with a variable height. By height, we mean the distance between the surface that comes into contact with the bottom of the vein 39 and the surface that is flush with the external surface of the cone. In this embodiment, the height of the cover 3 varies between a first height hl, corresponding to the height of the platform 31, and a height h2 corresponding to the height of the portion 30. Therefore, hl is greater than h2.

[0063] According to one variant, the cover could have a symmetrical shape with respect to the N axis. In this way, the cover could be reversible.

[0064] Generally, the shape and height of the plug depend on the shape and height of the vein to be plugged.

[0065] This platform 31 has a rounded shape so as to form an extension of the portion 30 and to retain the oblong shape of the cover 3.

[0066] The platform 31 is configured to be positioned opposite the first threaded hole 40, and more precisely over the entrance of the first threaded hole 40. In this way, the fact that the cover is fixed so as to close the vein 39 therefore leaves room for the head of the first fixing screw regardless of its positioning and tightening.

[0067] In order to keep the cover 3 fixed against the upstream cone 1, fastening means are provided. Here, the cover 3 has a through hole 33 configured to be positioned opposite a second threaded hole 50 formed in the groove 39, and adapted to cooperate with a second fixing screw 5 so as to fix the cover 3 onto the upstream cone 1.

[0068] In other words, the cover 3 is traversed by a through hole 33 configured to be positioned opposite a second threaded hole 50 formed at the bottom of the vein 39, when the cover is in the position of closing the vein, a second fixing screw 5 being provided to fit into this second threaded hole 50 so as to fix the cover 3 on the upstream cone 1.

[0069] Preferably, the through hole 33 has a filleted end and the second fixing screw 5 is a threaded screw so that, once screwed into the through hole 33 and into the second threaded hole 50, the head of the second fixing screw 5 is fully entered into the through hole 33.

[0070] Here, the second tapped orifice 50 extends along an axis N normal to the extension direction E of the vein 39.

[0071] In this way, and more specifically during the rotation of the turbomachine, the cover is held fixed on the upstream cone. Furthermore, these fastening means are easily removable.

[0072] In this embodiment, and as particularly visible in figures 6 and 7, the second tapped hole 50 of the second fixing screw 5 is centered on the first portion 30.

[0073] In this way, the through hole 33 and the second tapped orifice 50 form indexing means for the placement of the cover 3 so as to close the vein 39.

[0074] In this embodiment, and as seen in particular in figures 8a and 8b, the inlet cone here comprises at least three covers, each configured to be fixed to the upstream cone 1 so as to close a vein 39. As a result, three veins 39 are formed in this embodiment, each having a tapped orifice formed opening so as to be able to house in each a first fixing screw 4 of the upstream cone to the downstream ferrule.

[0075] The three veins formed in the upstream cone are uniformly distributed around the periphery of the upstream cone. Here, two veins are approximately 120° apart so that the three veins are uniformly distributed around the periphery of the upstream cone.

[0076] We now present, in relation to figures 5 to 7, the different stages of fixing the components of the inlet cone, in particular the upstream cone with the downstream ferrule, and the cover on the upstream cone.

[0077] As illustrated in [Fig. 5], the first fixing step consists of inserting the first fixing screw 4 into the first tapped hole 40 and screwing it in so that the head of the first fixing screw 4 either flush in the vein 39.

[0078] Previously, an alignment step of the upstream cone and the downstream ferrule is necessary so that the portion of the first tapped orifice 40 formed in the upstream cone 1 is aligned with the portion of the first tapped orifice 40 formed in the downstream ferrule 2.

[0079] Then, as illustrated in [Fig.6], the cover 3 is positioned opposite the vein so that the through hole 33 is positioned opposite the second tapped hole 50 formed in the vein 39, and then it is inserted into the vein 39 so as to close it.

[0080] Next, the user inserts the second fixing screw 5 into the second tapped hole 50 and then screws it in so that the head of the second fixing screw 5 is fully inserted into the through hole 33.

Claims

Demands

1. An inlet cone (9) for an aircraft turbomachine fan mounted to rotate about an axis of rotation (R), comprising an upstream cone (1) fixed by at least one first fixing screw (4) to a downstream ferrule (2), said first fixing screw (4) being configured to fit into a first threaded orifice (40) formed partly in said upstream cone (1) and in said downstream ferrule (2), and opening into a channel (39) machined on said upstream cone (1), characterized in that the inlet cone (9) also comprises a cover (3) configured to fit onto said upstream cone (1) so as to close said channel (39), the upstream cone (1), the downstream ferrule (2), and said cover (3) together forming a substantially continuous external surface of said inlet cone (9), the inlet cone (9) further comprising sealing means provided between the periphery of said cover (3) and the outline of said vein (39).

2. Inlet cone (9) according to claim 1, characterized in that the cover (3) has a through hole (33) configured to be positioned opposite a second tapped orifice (50) formed in said vein (39), and adapted to cooperate with a second fixing screw (5) so as to fix said cover (3) on said upstream cone (1).

3. Inlet cone (9) according to any one of claims 1 or 2, characterized in that said cover (3) has a shape complementary to said vein (39).

4. Inlet cone (9) according to claim 2 or 3, characterized in that said cover (3) comprises a portion (30) having a substantially oblong shape, extended by a platform (31) having a second height (h2) lower than the first height (hl), said platform (31) being configured to position itself opposite said first tapped orifice (40).

5. Inlet cone (9) according to claim 4 dependent on claim 2, characterized in that the second tapped orifice (50) of the second fixing screw (5) is centered on the first portion (30).

6. Inlet cone (9) according to any one of claims 2 to 5, characterized in that the second tapped orifice (50) extends along an axis (N) normal to an extension direction (E) of said vein (39).

7. A fan for an aircraft turbomachine mounted to rotate about an axis of rotation (R), characterized in that it comprises a inlet cone according to any one of claims 1 to 6.

8. Aircraft turbomachine comprising a blower (9) according to claim 7.

9. Aircraft turbomachine according to claim 8, characterized in that it is a turbojet.

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