FLANGE SYSTEM FOR A FAN BLADE WITH LOW RADIAL OVERALL DISTANCE

Abstract

The invention relates to a fan stator module (10), in particular for an aircraft turbomachine test bench, comprising: - an annular hub (11), - at least one blade (12) provided with a blade root (15) arranged in the blade root housing (13), - a clamping system (18) in position of the blade (12) comprising: - a clamping pad (21) movable in translation between: an unlocking position in which the clamping pad (21) is spaced apart from the blade root (15) to allow a modification of an angular position of the blade (12), and a locking position in which the clamping pad (21) cooperates with a groove (17) made in the blade root (15) so as to ensure angular locking and radial locking of the blade (12). Figure 3

Description

Title of the invention: FLANGE SYSTEM FOR A FAN BLADE WITH SMALL RADIAL OVERALL SIZE

[0001] The present invention relates to a clamping system for a fan rectifier blade, stator, with small radial dimensions. The invention finds a particularly advantageous application in the field of aeronautics, in particular with test machines for a turbomachine test bench.

[0002] [Fig.l] shows such a test machine 1 comprising a turbomachine fan 2 intended to compress the air entering the engine. A part of this air constitutes the primary flow F1 circulating in a primary vein 3 and another part of this air constitutes the secondary flow F2 circulating in a secondary vein 4. The primary flow F1 passes through a low-pressure compressor integral with the fan 2, 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] For this purpose, the fan 2 comprises a rotor module 5 with moving vanes and a stator module 6 with fixed vanes called OGV (for "Outlet Guide Vane" in English). An inlet cone 7 is mounted at the upstream end of the rotor module 5 to divert part of the air flow which enters the interior of the turbojet towards the blades of the fan 2.

[0004] The rotor module 5 comprises a plurality of blades mounted on an annular hub called a "fan disc" driven in rotation by the low-pressure turbine. The rotor module 5 provides acceleration to the air particles, by deflecting them relative to the X axis of the engine. The stator module 6 slows down the air particles and transforms part of their speed into pressure. The stator module 6 brings the air flow, accelerated by the rotor module 5, back into the X axis of the engine.

[0005] The blades of the stator module 6 are of the variable pitch type, that is to say that they can be arranged in a predetermined angular position around their respective axis in order to adapt and optimize this position depending in particular on the speed of the turbomachine. For this purpose, a clamping system makes it possible to selectively authorize or block a rotation of the blades of the stator module 6 in order to select a desired angular position.

[0006] However, the thickness E between the primary vein 3 and the secondary vein 4 measured in a radial direction relative to the axis X of the motor is relatively small. There is therefore a need to develop a clamping system with small radial size that can be easily integrated inside an internal volume of the stator module.

[0007] The invention aims to effectively meet this need by proposing a fan stator module, in particular for an aircraft turbomachine test bench, comprising: - an annular hub comprising at least one blade root housing, - at least one blade provided with a blade root arranged in the blade root housing, - a system for clamping the blade in position comprising: - a clamping pad movable in translation, in particular in an axial direction relative to an axis of the annular hub, between: - an unlocking position in which the clamping pad is spaced apart from the blade root to allow a modification of an angular position of the blade, and - a locking position in which the clamping pad cooperates with a groove made in the blade root so as to ensure angular locking and radial locking of the blade.

[0008] The invention thus makes it possible, thanks to the translational movement of the clamping pad, to compactly integrate the clamping device inside the annular hub extending between the primary vein and the secondary vein of the test turbomachine.

[0009] According to one embodiment of the invention, the clamping pad is carried by a rod movable in translation relative to the annular hub.

[0010] According to one embodiment of the invention, a pressure screw is capable of locking the rod in translation when the clamping pad is in the locking position.

[0011] According to one embodiment of the invention, said stator module comprises an inclined face produced on the clamping pad and an inclined face produced on the annular hub against which a compressometer is intended to come to bear to apply a force on the clamping pad before tightening the pressure screw.

[0012] According to one embodiment of the invention, said stator module further comprises an elastic member urging the clamping pad into the locking position.

[0013] According to one embodiment of the invention, the elastic member takes the form of an elastic strip.

[0014] According to one embodiment of the invention, the clamping pad comprises a notch intended to cooperate with a tool making it possible to retract the clamping pad from the locked position to the unlocked position.

[0015] According to one embodiment of the invention, the clamping pad has a wedge-shaped end intended to cooperate with the groove of corresponding shape.

[0016] According to one embodiment of the invention, one face of the clamping pad in contact with the annular hub is covered by a layer of a coating with a low coefficient of friction.

[0017] According to one embodiment of the invention, a closing cover closes a housing of the annular hub in which the clamping pad is arranged so as to reconstitute a portion of a secondary vein of the turbomachine.

[0018] According to one embodiment of the invention, the pressure screw is inserted inside a fixing hole made in the closing cover to ensure fixing of said cover. closing on the annular hub.

[0019] The present invention will be better understood and other characteristics and advantages will become apparent upon reading the detailed description which follows, comprising embodiments given by way of illustration with reference to the appended figures, presented as non-limiting examples, which may serve to complete the understanding of the present invention and the description of its embodiment and, where appropriate, contribute to its definition, in which:

[0020] [Fig-1] [Fig.l], already described, is a longitudinal sectional view of a machine of test for a test bench illustrating the low thickness between the primary vein and the secondary vein at the level of a stator module;

[0021] [Fig.2] [Fig.2] is a perspective view of a fan stator module for an aircraft turbomachine test bench according to the invention;

[0022] [Fig.3] [Fig.3] is a sectional view of a first embodiment of a clamping system for a fan stator module blade with low radial bulk according to the invention;

[0023] [Fig.4] [Fig.4] is a sectional view of a compressometer used with the embodiment of [Fig.3];

[0024] [Fig.5] [Fig.5] is a perspective and sectional view of a second embodiment of a clamping system for a fan stator module blade with small radial dimensions according to the invention.

[0025] It should be noted that, in Figures 2 to 5, the structural and / or functional elements common to the different embodiments may have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

[0026] [Fig. 2] shows a fixed fan stator module 10 for an aircraft turbomachine test bench comprising an annular hub 11 having an axis XI and a plurality of blades 12. The blades 12 extend radially outward from the annular hub 11 along their axis Y.

[0027] More specifically, the annular hub 11 comprises a plurality of housings 13 for receiving a blade root 15. Each blade root housing 13 has a cylindrical shape. The annular hub 11 may be a single-piece annular hub 11, i.e. it is made in a single part. Alternatively, the annular hub 11 is made in two coaxial annular parts assembled together. Each part of the annular hub 11 delimits a portion of the blade root housings 13.

[0028] The blades 12 are distributed angularly in a regular manner along a circumference of the annular hub 11. Each blade 12 is provided with a blade root 15 arranged inside a corresponding blade root housing 13. A blade root 15 of cylindrical shape has a groove 17 at its external periphery.

[0029] As can be seen in Figures 2 and 3, a clamping system 18 in position of the blade 12 comprises a clamping pad 21 movable in translation, in particular in an axial direction relative to the axis XI of the annular hub 11, between: - an unlocking position in which the clamping pad 21 is spaced apart from the blade root 15 to allow a modification of an angular position of the blade 12, and - a locking position in which the clamping pad 21 cooperates with the groove 17 made in the blade root 12 so as to ensure angular locking of the blade 12 around the axis Y and radial locking of the blade 12 relative to the axis XI.

[0030] The clamping pad 21 has a wedge-shaped end intended to cooperate with the groove 17 of corresponding shape. Thus, the groove 17 has inclined faces. The groove 17 can thus have a triangular-shaped section.

[0031] Advantageously, the clamping pad 21 is carried by a rod 22 movable in translation relative to the annular hub 11. The rod 22 is arranged inside an opening made in a portion of the annular hub 11 or in a ferrule fixed to the annular hub 11.

[0032] A pressure screw 25 is capable of locking the rod 22 in translation when the clamping pad 21 is in the locking position. The pressure screw 25 is arranged inside a bore 26 made in the annular hub 11. The pressure screw 25 has an axis X2 having a radial orientation relative to the axis XI of the annular hub 11. When the pressure screw 25 is tightened, the pressure screw 25 has one end bearing on the rod 22 to lock the rod 22 in translation. This makes it possible to maintain the force applied by the clamping pad 21 on the blade root 15.

[0033] According to the embodiment of [Fig. 3], a compressometer 33 is intended to bear against an inclined face 29 made on the clamping pad 21 and an inclined face 30 made on the annular hub 11 or a ferrule. The compressometer 33 is intended to apply a force to the clamping pad 21 before tightening the pressure screw 25. For this purpose, as can be seen in [Fig. 4], the compressometer 33 has a wedge-shaped end 34 intended to bear against the two inclined faces 29, 30. The compressometer also has an end 35 via which an operator or an external force applicator can apply a force.

[0034] The operation of the clamping system 18 of [Fig. 3] is described below. Firstly, the clamping shoe 21 is retracted axially towards the unlocking position so as to free up the space inside the blade root housing 13 for mounting the blade 12.

[0035] Once the blade 12 is placed inside the blade root housing 13 and oriented according to the desired angular position, the clamping pad 21 is moved into the locking position.

[0036] The compressometer 33 is used to apply the desired force of the clamping pad 21 to the blade root 15 by inserting the wedge-shaped end 34 between the two inclined faces 29, 30 along the arrow F. Given that the wedging force of the blades 12 is of the order of 5N.m and that the diameter of the pivot of the profiles is of the order of 80mm, the force to be applied with the compressometer 33 is of the order of 20daN.

[0037] The pressure screw 25 is then tightened so as to maintain the clamping force applied by the clamping pad 21 on the blade root 15. The blade root 15 is then held clamped between a wall of the blade root housing 13 and the clamping pad 21. The blade 12 is thus immobilized in the desired angular position. The compressometer 33 can then be removed.

[0038] Once all the blades 12 are mounted on the annular hub 11, a closing cover 38 closes a housing of the annular hub 11 in which the clamping pad 21 is arranged so as to reconstitute a portion of the secondary vein of the turbomachine.

[0039] In the embodiment of [Fig. 5], an elastic member 40 biases the clamping pad 21 into the locking position. The elastic member 40 bears on the one hand against a face of the annular hub 11 and on the other hand against an end of the rod 22 of the clamping pad 21. The face of the annular hub 11 against which the elastic member 40 bears may extend in a plane perpendicular to a direction of extension of the rod 22. In the example shown, the elastic member 40 takes the form of an elastic strip, in particular V-shaped. Alternatively, the elastic member 40 may take the form of a spring or any other elastic member suitable for the application.

[0040] The clamping pad 21 has a notch 41 intended to cooperate with an unlocking tool (not shown). The notch 41 may be made on an upper face of the clamping pad 21. The unlocking tool may for example have a tip in the form of a flat screwdriver or any other shape suitable for the application.

[0041] The operation of the clamping system 18 of [Fig. 5] is described below. Firstly, the clamping pad 21 is retracted axially using the unlocking tool inserted inside the notch 41 to move the clamping pad 21 from the locking position to the unlocking position. This makes it possible to free up the space inside the blade root housing 13 for mounting the blade 12.

[0042] Once the blade 12 is placed inside the blade root housing 13 and oriented according to the desired angular position, the unlocking tool is removed, so that the elastic member 40 urges the clamping pad 21 towards the locking position.

[0043] The pressure screw 25 is then tightened so as to maintain the clamping force applied by the clamping pad 21 on the corresponding blade root 15. The blade 12 is thus immobilized in the desired angular position.

[0044] Once all the blades 12 are mounted on the annular hub 11, a closing cap 38 closes a housing of the annular hub 11 in which the clamping pad 21 is arranged so as to reconstitute a portion of the secondary vein of the turbomachine. The pressure screw 25 can be inserted inside a fixing hole 42 made in the closing cap 38 to ensure fixing of said closing cap 38 on the annular hub 11.

[0045] In all embodiments of the invention, a face of the clamping pad 21 in contact with the annular hub 11 may be covered by a layer of a low-friction coating 43, such as Teflon (trade name). This makes it possible to reduce the friction between the underside of the clamping pad 21 and the annular hub 11 in order to facilitate the application of the clamping force. In the example shown, the face of the clamping pad 21 covered by the layer of a low-friction coating 43 is a radially lower face of the clamping pad 21.

[0046] Of course, the various features, variants and / or embodiments of the present invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

[0047] 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 may be envisaged by those skilled in the art within the scope of the present invention and in particular all combinations of the different operating modes described above, which may be taken separately or in association.

Claims

Claims

1. Fan stator module (10), in particular for an aircraft turbomachine test bench, comprising: - an annular hub (11) comprising at least one blade root housing (13), - at least one blade (12) provided with a blade root (15) arranged in the blade root housing (13), characterized in that said stator module (10) further comprises a clamping system (18) in position of the blade (12) comprising: - a clamping pad (21) movable in translation between: - an unlocking position in which the clamping pad (21) is spaced apart from the blade root (15) to allow a modification of an angular position of the blade (12), and - a locking position in which the clamping pad (21) cooperates with a groove (17) made in the blade root (15) so as to ensure angular locking and radial locking of dawn (12).

2. Stator module according to claim 1, characterized in that the clamping pad (21) is carried by a rod (22) movable in translation relative to the annular hub (11).

3. Stator module according to claim 2, characterized in that a pressure screw (25) is capable of locking the rod (22) in translation when the clamping pad (21) is in the locking position.

4. Stator module according to claim 3, characterized in that it comprises an inclined face (29) produced on the clamping pad (21) and an inclined face (30) produced on the annular hub (11) against which a compressometer (33) is intended to come to bear to apply a force on the clamping pad (21) before tightening the pressure screw (25).

5. Stator module according to any one of claims 1 to 4, characterized in that it further comprises an elastic member (40) urging the clamping pad (21) into the locking position.

6. Stator module according to claim 5, characterized in that the elastic member (40) takes the form of an elastic strip.

7. Stator module according to any one of claims 1 to 6, characterized in that the clamping pad (21) comprises a notch (41) intended to cooperate with a tool making it possible to retract the clamping pad (21) from the locked position to the unlocked position.

8. Stator module according to any one of claims 1 to 7, characterized in that the clamping pad (21) has a wedge-shaped end intended to cooperate with the groove (17) of corresponding shape.

9. Stator module according to any one of claims 1 to 8, characterized in that a face of the clamping pad (21) in contact with the annular hub (11) is covered by a layer of a low friction coefficient coating (43).

10. Stator module according to any one of claims 1 to 9, characterized in that a closing cover (38) closes a housing of the annular hub (11) in which the clamping pad (21) is arranged so as to reconstitute a portion of a secondary vein of the turbomachine.

11. Stator module according to claims 3 and 10, characterized in that the pressure screw (25) is inserted inside a fixing hole (42) made in the closing cover (38) to ensure fixing of said closing cover (38) on the annular hub (11).

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