DEVICE FOR CLOSING AN OPENING MADE IN AN AERODYNAMIC PART

Abstract

The invention relates to a device for closing a through-hole (33) made in an aerodynamic part (21) defining at least in part an aerodynamic duct face (34) comprising: - a pusher (37) having a closing section (37.1) inserted inside the through-hole (33) of the aerodynamic part (21), a stop (38), a spring retaining section (37.2), and a rotational indexing device (39) for maintaining an orientation of an end face of the closing section (37.1) relative to the aerodynamic duct face (34), and - a return spring (40) disposed around the spring retaining section (37.2), said return spring (40) being able to press the stop (38) against the aerodynamic part (21), so that the end face of the closing section (37.1) is flush with the aerodynamic vein face (34). Figure 4

Description

Title of the invention: DEVICE FOR CLOSING AN OPENING MADE IN AN AERODYNAMIC PART

[0001] The present invention relates to a device for closing an opening made in an aerodynamic part. The invention finds a particularly advantageous, but not exclusive, application with a rectifier module or a fan rotor module.

[0002] The operating principle of a turbomachine fan is to compress the air entering the engine. Part of this air constitutes the primary flow, delimited by a primary stream, and another part of this air constitutes the secondary flow, delimited by a secondary stream. The primary flow passes through a low-pressure compressor attached to the fan, through a high-pressure compressor, through the combustion chamber, through the high-pressure turbine, and finally through the low-pressure turbine before being ejected.

[0003] The applicant has developed a test machine for a test bench, in particular a blower for an aerodynamic demonstrator which has only one airflow and which does not have a low-pressure compressor, nor a high-pressure compressor or a combustion chamber.

[0004] Fig. 1 shows such a test machine 1 comprising, from upstream to downstream, an upstream flow channel 2, a blower 3 having a rotor module 4 with moving blades and a straightener module 5 with fixed blades called OGV (for "Outlet Guide Vane" in English), as well as a downstream flow channel 6.

[0005] The rotor module 4 comprises a plurality of blades mounted on a cylindrical hub called a "fan disc" driven in rotation by a pressure turbine supplied with air by the test bench. The rotor module 4 accelerates the air particles by deflecting them from the X-axis of the motor. The rectifier module 5 slows the air particles and converts part of their velocity into pressure. The rectifier module 5 returns the airflow, accelerated by the rotor module 4, to the X-axis of the motor.

[0006] During a test campaign, it is important to be able to quickly assemble and disassemble a blade and adjust its angular position to find the optimal setting for the turbomachine. Therefore, these operations must be performed as quickly as possible to minimize downtime of the test machine during the campaign. These operations must also be able to be carried out in a constrained environment. dimensionally without having to dismantle the test machine which is fully instrumented.

[0007] Figure 2 shows a locking system 7 for rotation of a blade 8 comprising a flange 9 bearing against one end of a corresponding blade foot 10. The flange 9 is associated with a clamping screw 11 inserted inside a through opening 12 of the hub 13 of the rotor module 4 and cooperating with a clamping nut 14. The clamping screw 11 makes it possible to lock the blade 8 against rotation about its pivot axis by pressing the flange 9 against the hub 13.

[0008] The clamping screws 11 each have an imprint 15 which generates defects in the geometry of the aerodynamic duct, which degrades the aerodynamic performance of the aircraft engine.

[0009] The invention aims to effectively remedy the aforementioned drawbacks by proposing a device for closing a through-hole made in an aerodynamic part defining at least part of an aerodynamic duct face, said closing device comprising: - a pusher comprising a sealing section inserted inside the through-hole of the aerodynamic part, a stop, a spring retaining section, and a rotational indexing device to maintain an orientation of an end face of the sealing section relative to the aerodynamic duct face, and - a return spring arranged around the spring retaining section, said return spring being able to stress the stop against the aerodynamic part, so that the end face of the sealing section is flush with the aerodynamic rib face.

[0010] The invention thus improves the aerodynamic performance of the assembly by masking the through-hole that could cause airflow disturbances inside a turbomachine. The invention also allows a profiled surface of the tappet to be aligned with a profiled surface of the annular hub so as to eliminate any aerodynamic step. The invention also has the advantage of being a simple solution to implement, requiring a minimum number of parts.

[0011] According to one embodiment of the invention, the rotational indexing shape is made in the spring retaining section disposed partly inside a correspondingly shaped guide opening made in a flange.

[0012] According to one embodiment of the invention, the rotational indexing shape is made in a lateral face of the stop having a shape complementary to a housing made in the annular hub.

[0013] According to one embodiment of the invention, the rotational indexing shape is made in a lateral face of the obturating section having a shape complementary to the through opening.

[0014] According to one embodiment of the invention, the stop comprises an annular portion defining a housing for the return spring.

[0015] According to one embodiment of the invention, the through opening made in the aerodynamic element is a threaded opening.

[0016] The invention also relates to a module, in particular for an aircraft turbomachine test bench, comprising: - an annular hub comprising at least one blade foot housing, - at least one blade fitted with a blade foot intended to be placed inside the blade foot housing, - a rotational locking system for the blade, and - a sealing device as previously defined, said sealing device comprising a pusher having a sealing section inserted inside a through opening made in the annular hub.

[0017] According to one embodiment of the invention, the blade rotation locking system comprises a flange bearing against the blade foot.

[0018] According to one embodiment of the invention, an elastic preload member is disposed between a bottom of the blade foot housing and the flange.

[0019] According to one embodiment of the invention, the sealing device comprises a return spring having a stiffness coefficient lower than a stiffness coefficient of the elastic preload member.

[0020] The present invention will be better understood and other features and advantages will become apparent upon reading the following detailed description, which includes embodiments given by way of illustration with reference to the accompanying figures, presented by way of non-limiting examples, which may serve to complete the understanding of the present invention and the explanation of its implementation and, where appropriate, contribute to its definition, on which:

[0021] [Fig-1] Fig. 1, already described, is a longitudinal cross-sectional view of a machine test with which the invention can be implemented;

[0022] [Fig.2] Fig.2, already described, is a perspective and partial cross-sectional view of a locking system for a blade according to the state of the art;

[0023] [Fig.3] Fig.3 is a perspective view of a rotor module for a test bench aircraft turbomachine according to the present invention;

[0024] [Fig.4] Fig.4 is a perspective and detailed cross-sectional view of a foot blade and a device for closing an opening according to the invention used with a blade locking system;

[0025] [Fig. 5] Fig. 5 is a perspective view of a push button used with the device sealing according to the invention;

[0026] [Fig.6] The [Fig.6] is a perspective view of a portion of a flange provided with an opening intended to receive the pusher of the closing device according to the invention;

[0027] [Fig.7a] [Fig.7b] Figures 7a and 7b are cross-sectional views of a shutter device according to the invention respectively in an operating state and in an unlocked state.

[0028] It should be noted that, in Figures 3 and following, the structural and / or functional elements common to the different embodiments have the same reference numerals. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

[0029] Fig. 3 shows a rotor module 20 for an aircraft turbomachine test bench comprising an annular hub 21 having an axis XI and a plurality of blades 22.

[0030] The annular hub 21 comprises a plurality of blade root housings 23. Advantageously, the annular hub 21 is a single-piece hub. Alternatively, the annular hub 21 may be formed by two coaxial annular elements fixed to each other and defining between them the blade root housings 23.

[0031] The blades 22 extend radially outwards from the hub 21. The blades 22 are regularly distributed angularly along a circumference of the hub 21. Each blade 22 is provided with a blade foot 25 of generally cylindrical shape intended to be disposed inside a corresponding blade foot housing 23.

[0032] A locking system 26 for rotation of the blade 22 allows, in an unlocked state, the blade foot 25 to be rotated within a corresponding housing 23 around an axis X2 of the blade foot 25 so as to select a desired angular position of the blade 22 for a test and, in a locked state, to immobilize the blade 22 within the housing 23 in the desired angular position.

[0033] To this end, as can be seen in [Fig. 4], the locking system 26 comprises a flange 27 bearing against the blade root 25, and a preload elastic element 30 disposed between a bottom of the blade root housing 23 and the flange 27. Preferably, the preload elastic element 30 is a spring. Alternatively, the preload elastic element 30 may be in the form of a spring blade, or any other elastic element suitable for the application.

[0034] The flange 27 has an elongated plate shape having a portion in contact with the blade foot 25. The flange 27 has an opening 31 for the passage of an end portion of the blade foot 25 around which the elastic preload member 30 is arranged. The flange 27 also has a guide opening 32 into which a spring retaining section 37.2 is inserted, as described in more detail below.

[0035] A bearing face of the blade foot 25 in contact with the flange 27 extends in a substantially radial direction with respect to the axis X2 of the blade foot 25. The bearing face of the blade foot 25 may have a radius of curvature.

[0036] The annular hub 21 has a through opening 33 made in the annular wall of the hub 21. The through opening 33 is capable of disturbing the airflow along an aerodynamic duct face 34 defined at least in part by the annular hub 21. The through opening 33 has an axis extending radially with respect to the axis XI of the annular hub 21. The through opening 33 is a threaded opening.

[0037] A sealing device 35 is intended to seal the through opening 33. For this purpose, the sealing device 35 includes a pusher 37 with axis X3 having a sealing section 37.1 inserted inside the through opening 33, a stop 38 intended to bear against the annular hub 21, a spring retaining section 37.2, and a rotational indexing form 39 to maintain an orientation of the end face of the sealing section 37.1 relative to the aerodynamic duct face 34.

[0038] A return spring 40 is arranged around the spring retaining section 37.2. The return spring 40 is designed to press the stop 38 against the annular hub 21, such that an end face of the sealing section 37.1 is flush with the aerodynamic duct face 34. The return spring 40 bears against the stop 38 on one side and against the flange 27 on the other. Advantageously, the return spring 40 has a stiffness coefficient lower than that of the elastic preload element 30 in order to prevent stressing the flange 27 when the blade 22 separates. The return spring 40 is dimensioned so as not to compress when air passes through the duct due to a pressure difference outside the duct that is greater than the internal pressure.

[0039] More specifically, as can be seen in [Fig. 5], the stop 38 comprises a portion 38.1 intended to bear against the annular hub 21 and an annular portion 38.2 located in the extension of a radial end of the portion 38.1. The annular portion 38.2 has an axial orientation with respect to the axis X3 of the pusher 37. The annular portion 38.2 thus defines a housing open towards the flange 27 in which the return spring 40 is disposed.

[0040] The rotational indexing form 39 is formed in the spring retaining section 37.2, which is partially disposed inside a correspondingly shaped guide opening 32 formed in a flange 27 (see [Fig. 6]). The rotational indexing form 39 may have an oblong shape having at least one flat, in this case two flats 43 connected at their ends by rounded portions. Alternatively, the shape rotational indexing 39 can be a square, rectangular or any other shape preventing rotation of the pusher 37 around its axis X3.

[0041] Alternatively, as illustrated in [Fig. 7a], the rotational indexing shape 39 can be made in a lateral face of the stop 38 having a shape complementary to a housing made in the annular hub 21. Alternatively, the rotational indexing shape 39 can be made in a lateral face of the sealing section 37.1 having a shape complementary to the through opening 33. It is then possible to eliminate the portion of the section 37.2 inserted inside the guide opening 32 of the flange 27.

[0042] The operation of the shutter device 35 is described below with reference to figures 7a and 7b.

[0043] In an operating position shown in [Fig. 7a], the return spring 40 bearing against the flange 27 forces the pusher 37 against the hub 21, thus enabling its radial stop. The return spring 40 brings the stop 38 against the hub 21 under conditions of standstill or low-speed rotation of the hub 21. At high speed, centrifugal force can contribute to bringing the stop 38 against the hub 21.

[0044] Furthermore, the elastic preload member 30 forces the flange 27 against the blade foot 25. The blade foot 25, bearing against the annular hub 21 by means of a circlip-type elastic washer 41, is then immobilized in a predetermined angular position.

[0045] In an unlocked position shown in [Fig. 7b], tightening a push screw 44 inside the tapped opening 33 axially displaces the pusher 37 along arrow F1, so that the return spring 40 is compressed and the stop 38 exerts a force against the flange 27 along arrows F2. This has the effect of compressing the elastic preload member 30, thereby allowing rotation of the blade 22. The blade 22 can then be rotated to select a desired angular position.

[0046] Loosening the push-button screw 44 until it is removed returns the shutter device 35 to its operating position to lock the blade 22 in the desired position. It is then possible to test the blower with this new angular configuration of the blade 22.

[0047] The operations of manipulating the blade 22 and tightening or loosening the pusher screw 44 can be carried out by a human operator or automatically by a robot.

[0048] In the case where the necessary force to detach the flange 27 (force to be applied on the pusher 37) is less than the ability of a human operator to press on it, the opening 33 is not necessarily tapped.

[0049] Alternatively, the blower module can be a rectifier module.

[0050] The invention is not limited to use with a blower test machine. Indeed, the invention can also be used with a turbomachine requiring the sealing of an opening made in an aerodynamic part that defines at least part of a flow face. More generally, the invention can be implemented with any aerodynamic part having a through-hole that must be sealed to improve the aerodynamic performance of said part.

[0051] Of course, the different features, variants and / or embodiments of the present invention can be combined with each other in various ways insofar as they are not incompatible or mutually exclusive.

[0052] Furthermore, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms, and other variants that a person skilled in the art may consider within the scope of the present invention, and in particular all combinations of the different modes of operation described above, which may be taken separately or in combination.

Claims

Demands

1. A closure device (35) for a through-hole (33) formed in an aerodynamic part (21) defining at least partially an aerodynamic duct face (34), characterized in that said closure device (35) comprises: - a pusher (37) having a closure segment (37.1) inserted inside the through-hole (33) of the aerodynamic part (21), a stop (38), a spring retainer segment (37.2), and a rotational indexing device (39) for maintaining an orientation of an end face of the closure segment (37.1) relative to the aerodynamic duct face (34), and - a return spring (40) disposed around the spring retainer segment (37.2), said return spring (40) being capable of pressing the stop (38) against the aerodynamic part (21), so that the end face of the sealing section (37.1) is flush with the aerodynamic vein face (34).

2. A sealing device according to claim 1, characterized in that the rotational indexing shape (39) is made in the spring retaining section (37.2) disposed partly inside a correspondingly shaped guide opening (32) made in a flange (27).

3. A sealing device according to claim 1, characterized in that the rotational indexing shape (39) is made in a lateral face of the stop (38) having a shape complementary to a housing made in the annular hub (21).

4. Device according to claim 1, characterized in that the rotational indexing shape (39) is made in a lateral face of the sealing section (37.1) having a shape complementary to the through opening (33).

5. A sealing device according to any one of claims 1 to 4, characterized in that the stop (38) comprises an annular portion (38.2) defining a housing for the return spring (40).

6. A sealing device according to any one of claims 1 to 5, characterized in that the through opening (33) made in the aerodynamic element is a threaded opening.

7. Module, in particular for an aircraft turbomachine test bench, characterized in that it comprises:

8.

9.

10. - an annular hub (21) comprising at least one blade foot housing (23), - at least one blade (22) equipped with a blade foot (25) intended to be placed inside the blade foot housing (23), - a locking system (26) for rotation of the blade (22), and - a sealing device (35) defined according to any one of the preceding claims, said sealing device (35) comprising a pusher (37) having a sealing section (37.1) inserted inside a through opening (33) made in the annular hub (21). Module according to claim 7, characterized in that the locking system (26) in rotation of the blade (22) comprises a flange (27) bearing against the blade foot (25). Module according to claim 8, characterized in that an elastic preload member (30) is disposed between a bottom of the blade foot housing (25) and the flange (27). Module according to claim 9, characterized in that the sealing device (35) comprises a return spring (40) having a stiffness coefficient lower than a stiffness coefficient of the elastic preload member (30).

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