FAN BLADE RETAINING SHIM WITH BROKEN FOOT

Abstract

The present invention relates to an assembly for a fan module for an aircraft turbomachine test bench comprising: - a blade (7) provided with a blade root (8), - a blade pivot (9) comprising a cell (16) in which the blade root (8) is inserted, said cell (16) comprising bearing surfaces (19), and - at least one holding wedge (21) arranged under the blade root (8) being inserted inside a groove of complementary shape made in the blade root (8) so as to press lateral faces (23) of the blade root (8) against the bearing surfaces (19) of the cell (16) of the blade pivot (9). Figure 5

Description

Title of the invention: WEDGE FOR HOLDING A BLADE OF A BROKEN FOOT FAN

[0001] The present invention relates to a wedge for holding a fan blade with a broached root. The invention finds a particularly advantageous application with the blades of a fan rotor module belonging to a test machine intended to test different parts of the turbomachine and to optimize the operating settings of the turbomachine.

[0002] [Fig.l] shows a test machine 1 for a test bench comprising from upstream to downstream, an upstream flow vein 2, a fan 3 having a rotor module 4 with moving blades and a rectifier module 5 with fixed blades, as well as a downstream flow vein 6.

[0003] The rotor module 4 provides acceleration to the air particles, by deflecting them relative to the X axis of the engine. The rectifier module 5 slows down the air particles and transforms part of their speed into pressure. The rectifier module 5 brings the air flow, accelerated by the rotor module 4, back into the X axis of the engine.

[0004] During a test campaign, it is important to be able to ensure rapid assembly and disassembly of a blade as well as modification of its angular setting in order to find an optimum setting for the turbomachine. These operations must be able to be carried out as quickly as possible without having to disassemble the machine since the latter is fully instrumented.

[0005] However, it may be difficult to achieve precise adjustment of the angular position of certain types of blades 7, such as that shown in [Fig. 2] having a broached root 8 mounted on a blade pivot 9 of axis XL. Indeed, the blade root 8 is short relative to the chord of the blade 7 and positioned eccentrically relative to the center of gravity G of the blade 7. Indeed, the ratio between the length of the broach and the chord of the blade creates a moment M at the level of the blade root 8. Consequently, poor timing of the blade root 8 inside the broached groove of the blade root 8 induces clearances amplifying the forces and shocks undergone by the blade 7.

[0006] The invention aims to effectively remedy the aforementioned drawbacks by proposing an assembly for a fan module for an aircraft turbomachine test bench comprising: - a dawn with a dawn foot, - a blade pivot comprising a cell in which the blade root is inserted, said cell comprising bearing surfaces, and - at least one retaining wedge placed under the blade root is inserted inside of a complementary shaped groove made in the blade root so as to press the lateral faces of the blade root against the bearing surfaces of the blade pivot cell.

[0007] According to one embodiment of the invention, the holding wedge has a longitudinal extension direction extending substantially perpendicular to a longitudinal extension direction of the blade root.

[0008] According to one embodiment of the invention, a pressure screw is inserted inside a tapped hole made in the blade pivot to ensure that the retaining wedge is locked in position.

[0009] According to one embodiment of the invention, the retaining wedge has beveled edges.

[0010] According to one embodiment of the invention, two platforms at least partially cover the blade pivot and in that the retaining wedge is made of one material with one of the platforms.

[0011] According to one embodiment of the invention, the holding wedge has a rectangular shape so as to define plane supports perpendicular to an axis of the blade pivot.

[0012] According to one embodiment of the invention, the retaining wedge is mounted in a shrink fit inside the blade pivot.

[0013] According to one embodiment of the invention, the retaining wedge comprises a protrusion at each end.

[0014] According to one embodiment of the invention, a bore intended to receive the retaining wedge has a through portion made in a first portion of a head of the blade pivot and a non-through portion made in a second portion of the head of the blade pivot.

[0015] According to one embodiment of the invention, an extraction hole opens on the one hand outside the blade pivot and on the other hand into the non-through portion of the receiving bore of the retaining wedge.

[0016] According to one embodiment of the invention, said assembly comprises a plurality of conical holding wedges arranged on either side of a median plane of the blade root.

[0017] According to one embodiment of the invention, said assembly comprises a first conical holding wedge and a second conical holding wedge arranged on a first side of the median plane of the blade root and a third conical holding wedge arranged on a second side of the median plane of the blade root between the first conical holding wedge and the second conical holding wedge.

[0018] According to one embodiment of the invention, the conical holding wedges may comprise a tapped hole intended to receive an extraction tool.

[0019] According to one embodiment of the invention, the blade root comprises conical grooves having a shape complementary to the conical holding wedges.

[0020] According to one embodiment of the invention, the blade root comprises a central wall ensuring separation of the conical retaining wedges arranged on either side of said central wall.

[0021] According to one embodiment of the invention, said assembly comprises at least one holding wedge constituted by a carriage movable in translation relative to the blade pivot, and perpendicular to the direction of longitudinal extension of the blade root, having an inclined face intended to come to bear against a face of the blade root.

[0022] 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 for illustrative purposes 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:

[0023] [Fig-1] [Fig.l], already described, is a longitudinal sectional view of a machine of test with which the invention is implemented;

[0024] [Fig.2] [Fig.2], already described, is a perspective view of a brocaded foot alb rotor module with which the invention is intended to be implemented;

[0025] [Fig.3] [Fig.3] is a perspective view of a rotor module for a test bench aircraft turbomachine comprising blades fitted with retaining wedges according to the invention;

[0026] [Fig.4] [Fig.4] is a perspective and sectional view of a rotor module hub showing the positioning of a retaining wedge according to the invention bearing against a blade root;

[0027] [Fig.5] [Fig.5] is a perspective view of a blade pivot and a blade shim. support according to the invention intended to ensure the support of a blade;

[0028] [Fig.6] [Fig.6] is a perspective view illustrating a positioning of a wedge for holding inside a groove of a blade root according to the invention;

[0029] [Fig.7] [Fig.7] is a perspective view of a modular assembly comprising a blade pivot and a set of platforms showing transparently the holding wedge according to the invention;

[0030] [Fig.8] [Fig.8] is a perspective view of a platform incorporating a wedge maintenance according to the present invention;

[0031] [Fig.9] [Fig.9] is a perspective view of a blade pivot and a blade shim. retaining mounted shrink-fit inside the blade pivot;

[0032] [Fig. 10] [Fig. 10] is a perspective view showing the receiving bore of the retaining wedge according to the invention made in the blade pivot;

[0033] [Fig. 11] [Fig. 11] is a side view showing the extraction hole of the retaining wedge according to the invention made in the blade pivot;

[0034] [Fig. 12] [Fig. 12] is a perspective view of a retaining wedge according to the invention provided with two protrusions;

[0035] [Fig. 13] [Fig. 13] is a sectional view of an alternative embodiment of the invention comprising conical-shaped retaining wedges;

[0036] [Fig. 14] [Fig. 14] is a top view of the alternative embodiment of the invention comprising conical-shaped holding wedges;

[0037] [Fig. 15] [Fig. 15] shows a conical shaped holding wedge according to the invention provided with a tapped hole intended to receive an extraction tool;

[0038] [Fig. 16] [Fig. 16] is a top view of a blade root according to the invention provided with a central wall ensuring separation of the conical holding wedges;

[0039] [Fig. 17] [Fig. 17] is a sectional view of an alternative embodiment of a holding wedge in the form of a carriage.

[0040] It should be noted that the structural and / or functional elements common to the different embodiments may have the same references from one figure to another. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

[0041] [Fig. 3] shows a fan rotor module 4 for an aircraft turbomachine test bench comprising an annular hub 11 having an axis X2 and a plurality of blades 7. The blades 7 extend radially projecting outwards from the hub 11. The blades 7 are distributed angularly in a regular manner along a circumference of the annular hub 11.

[0042] The annular hub 11 comprises a plurality of housings 12 for receiving blade pivots. The annular hub 11 may be formed from two coaxial annular elements, in this case an upstream annular element 13.1 and a downstream annular element 13.2, fixed to each other and defining between them the blade pivot housings 12. Thus, a blade pivot housing 12 is delimited by a portion of the upstream annular element 13.1 and a portion of the downstream annular element 13.2.

[0043] A blade 7 is secured to a corresponding blade pivot 9. For this purpose, a blade 7 comprises a blade root 8 called a "broached root" inserted into a groove or broach forming a cell 16 of complementary shape formed in a corresponding blade pivot 9. The complementary shapes of the blade root 8 and the cell 16 may in particular be dovetail, hammer-type, or fir-tree root shapes, or any other shape adapted to the application.

[0044] As can be seen in [Fig. 4], a blade pivot 9 of axis XI has a generally cylindrical shape. A blade pivot 9 may comprise an annular collar 17 intended to be inserted into a groove 18 of the annular hub 11. Such a configuration makes it possible to ensure radial retention of the blade pivot 9 inside a blade pivot housing 12.

[0045] The cell 16 made in the blade pivot 9 has lateral faces called bearing surfaces 19. The bearing surfaces 19 form a non-zero angle relative to a median plane of the blade pivot 9 extending in a longitudinal direction of a cell 16.

[0046] As can be seen in Figures 4, 5 and 6, at least one holding wedge 21 arranged under the blade root 8 is inserted inside a groove 22 of complementary shape made in the blade root 8 so as to press lateral faces 23 of the blade root 8 against the bearing surfaces 19 of the cell 16 of the blade pivot 9. The groove 22 is made in a lower face of the blade root 8 facing the bottom of the cell 16. The holding wedge 21 has a longitudinal extension direction DI extending substantially perpendicularly to a longitudinal extension direction D2 of the blade root 8.

[0047] The retaining wedge 21 has, for example, a parallelepiped shape. In the embodiment of [Fig. 4], the retaining wedge 21 has beveled edges. This allows the embedding of the retaining wedge 21 in the groove 22 of the blade pivot 9 to distribute the forces over larger surfaces. Such a configuration is optimized for a case of 3D woven or composite blade so as not to crumble the binder.

[0048] The depth of the groove 22 depends on the material of the blade. Indeed, for a woven composite material, it is necessary to machine as few fibers as possible in order to avoid weakening the blade 7. For a metallic material, it is only necessary to respect the distribution of internal stresses during operation.

[0049] A pressure screw 25 visible in figures 5 and 6 is inserted inside a tapped hole 26 made in the blade pivot 9 to ensure that the holding wedge 21 is locked in position. The pressure screw 25 locks the holding wedge 21 against the bottom of a bore 38 of the blade pivot 9 in which the holding wedge 21 is arranged. The pressure screw 25 extends parallel to the axis XI of the blade pivot 9.

[0050] As can be seen in [Fig.7], two platforms 28 arranged on either side of a blade 7, along a median plane PM passing through D2 and XI, at least partially cover the blade pivot 9. A platform 28 has an external face flush with an external face of the annular hub 11 in order to guarantee the aerodynamics of the fan.

[0051] In this case, a platform 28 shown alone in [Fig. 8] comprises a transverse flange 30 relative to the axis XI of the blade pivot 9. The transverse flange 30 is extended by a part 31 in the form of a half-ring situated around the blade pivot 9. The part is extended by a radial rim 32 bearing against a corresponding face of radial orientation of the blade pivot 9. The platforms 30 are held around a corresponding blade pivot 9 by means of a split elastic ring 33 (see [Fig. 7]), so as to obtain a manipulable and transportable assembly. The elastic ring is arranged inside a groove 34 formed in the platforms 28.

[0052] Advantageously, the holding wedge 21 is made of one material with one of the platforms 28. In this case, the holding wedge 21 is made of one material with the half-ring-shaped part 31.

[0053] In this embodiment, the holding wedge 21 has a rectangular shape so as to define plane supports perpendicular to the axis XI of the blade pivot 9. Such a configuration also makes it possible to obtain good control of the clearances.

[0054] In the embodiment of Figures 9, 10, 11 and 12, the retaining wedge 21 is preferably mounted shrink-fitted inside the blade pivot 9. For this purpose, the retaining wedge 21 shown in [Fig. 12] has a protrusion 37 at each end for shrink-fitting and / or taking up clearance at the end of assembly.

[0055] As can be seen in [Fig. 10], a head 43 of the blade pivot 9 corresponds to the part of the blade pivot 9 in which the cell 16 is formed. A first portion 43.1 and a second portion 43.2 of the head of the blade pivot 9 are arranged on either side of the cell 16. Advantageously, the bore 38 intended to receive the holding wedge 21 has a through portion 38.1 made in the first portion 43.1 of the head 43 of the blade pivot 9 and a non-through portion 38.2 made in the second portion 43.2 of the head of the blade pivot 9, as shown in FIGS. 9 and 10. This allows the holding wedge 21 to bear on the blade pivot 9 in the axis of the broaching. The bore 38 may have a rectangular section or any other shape complementary to the retaining wedge 21.

[0056] Furthermore, an extraction hole 39 visible in [Fig. 11] opens on the one hand to the outside of the blade pivot 9 and on the other hand into the non-through portion 38.2 of the bore 38 for receiving the retaining wedge 21. This extraction hole 39 is tapped to allow extraction of the retaining wedge 21 by a thrust screw (not shown) intended to push the retaining wedge 21 in order to be able to extract it from its tight mounting. Once the retaining wedge 21 has been removed, it is possible to change the blade 7. Alternatively, a system of retaining wedges is provided whose orientation and positioning ensures the plating with constraint (therefore without play).

[0057] In the embodiment of Figures 13, 14, 15 and 16, a plurality of conical holding wedges 21.1, 21.2, 21.3 are provided, arranged on either side of a median plane Pm of the blade root 8. The conical holding wedges 21.1, 21.2, 21.3 lift the blade root 8 to press it against the bearing surfaces 19 of the cell 16 of the blade pivot 9. The angle of the cone and the angle of the blade root 8 are inclined so as to direct and distribute the forces at right angles to the pressings between the inclined lateral faces 23 of the blade root 8 and the bearing surfaces 19 of the cell 16. In the example shown in [Fig. 13], the conical wedges 21.1, 21.2, 21.3 have horizontal axes. The opening angle of the conical wedges 21.1, 21.2, 21.3 is quite small. Alternatively, it may be envisaged to tilt the axis of the conical wedges 21.1, 21.2, 21.3 and increase their opening angle.

[0058] Advantageously, as shown in [Fig. 14], three conical holding wedges are used, namely a first conical holding wedge 21.1 and a second conical holding wedge 21.2 arranged on a first side of the median plane Pm of the blade root 8 and a third conical holding wedge 21 arranged on a second side of the median plane Pm of the blade root 8 between the first conical holding wedge 21.1 and the second conical holding wedge 21.2. The second side of the median plane Pm of the blade root 8 is opposite the first side of the median plane Pm of the blade root 8. Such a configuration makes it possible to obtain an isostatic assembly and to guarantee optimal plane support of the blade root 8 on the bearing surfaces 19 of the cell 16 of the blade pivot 9. The conical holding wedges 21.1, 21.2, 21.3 are positioned in conical cavities 41.1, 41.2, 41.3 of corresponding shape made in the blade pivot 9, so that after assembly, the cone / cone contact keeps them in position.

[0059] The conical holding wedges 21.1, 21.2, 21.3 may include a tapped hole 42 intended to receive an extraction tool, as shown in [Fig.15].

[0060] The blade root 8 preferably comprises conical grooves 22.1, 22.2, 22.3 having a shape complementary to the conical holding wedges 21.1, 21.2, 21.3, as shown in [Fig. 16]. This ensures correct axial positioning of the blade 7 in the blade pivot 9.

[0061] Furthermore, the blade root 8 comprises a central wall 45 ensuring separation of the conical holding wedges 21.1, 21.2, 21.3 arranged on either side of said central wall 45. The central wall 45 extends along the median plane Pm passing through a longitudinal extension direction of the blade root 8. The central wall 45 makes it possible to ensure during assembly that the conical holding wedges 21.1, 21.2 located on one side of the median plane Pm of the blade root 8 do not encroach on the conical holding wedge 21.3 arranged on the opposite side of the median plane Pm of the blade root 8. Such an assembly forms an embedded connection between the bearing surfaces 19 of the cell 16 and the blade root 8, the cone / cone support of the holding wedge 21.1, 21.2, 21.3 on the blade root 8 and the cone / cone support of the holding wedge 21.1, 21.2, 21.3 on the blade pivot 9.

[0062] In the embodiment of [Fig. 17], at least one holding wedge 21 is constituted by a carriage 48 movable in translation relative to the blade pivot 9, and perpendicular to the direction D2, having an inclined face 49 intended to come to bear against a face of the blade root 8. The holding in position of the carriage 48 can be ensured by a set of covers and circlips. The assembly is carried out by checking the perpendicularity of the blade 7 with the blade pivot 9. Then, it is necessary to ensure an equivalent and synchronized pressure on the holding wedges 21 until the stop to obtain a cone / cone locking.

[0063] Alternatively, the invention may be implemented with the blades of a fan rectifier module.

[0064] 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.

[0065] 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. Assembly for a fan module (4) for an aircraft turbomachine test bench comprising: - a blade (7) provided with a blade root (8), and - a blade pivot (9) comprising a cell (16) in which the blade root (8) is inserted, said cell (16) comprising bearing surfaces (19), characterized in that at least one holding wedge (21) arranged under the blade root (8) is inserted inside a groove (22) of complementary shape made in the blade root (8) so as to press lateral faces (23) of the blade root (8) against the bearing surfaces (19) of the cell (16) of the blade pivot (9).

2. Assembly according to claim 1, characterized in that the holding wedge (21) has a longitudinal extension direction (D1) extending substantially perpendicular to a longitudinal extension direction (D2) of the blade root (8).

3. Assembly according to claim 1 or 2, characterized in that a pressure screw (25) is inserted inside a tapped hole (26) made in the blade pivot (9) to ensure locking in position of the holding wedge (21).

4. Assembly according to any one of claims 1 to 3, characterized in that the holding wedge (21) has beveled edges.

5. Assembly according to any one of claims 1 to 3, characterized in that two platforms (28) at least partially cover the blade pivot (9) and in that the retaining wedge (21) is made of one material with one of the platforms (28).

6. Assembly according to claim 5, characterized in that the holding wedge (21) has a rectangular shape so as to define plane supports perpendicular to an axis (XI) of the blade pivot (9).

7. Assembly according to any one of claims 1 to 4, characterized in that the retaining wedge (21) is mounted shrink-fit inside the blade pivot (9).

8. Assembly according to claim 7, characterized in that the holding wedge (21) comprises a protrusion (37) at each end.

9. Assembly according to any one of claims 1 to 8, characterized in that a bore (38) intended to receive the retaining wedge (21) has a through portion (38.1) made in a first portion of a head (43) of the blade pivot (9) and a non-through portion (38.2) made in a second portion of the head (43) of the blade pivot (9).

10. Assembly according to claim 9, characterized in that an extraction hole (39) opens on the one hand outside the blade pivot (9) and on the other hand into the non-through portion (38.2) of the bore (38) for receiving the retaining wedge (21).

11. Assembly according to claim 1 or 2, characterized in that it comprises a plurality of conical holding wedges (21.1, 21.2, 21.3) arranged on either side of a median plane (Pm) of the blade root (8).

12. Assembly according to claim 11, characterized in that it comprises a first conical holding wedge (21.1) and a second conical holding wedge (21.2) arranged on a first side of the median plane (Pm) of the blade root (8) and a third conical holding wedge (21.3) arranged on a second side of the median plane (Pm) of the blade root (8) between the first conical holding wedge (21.1) and the second conical holding wedge (21.2).

13. Assembly according to claim 11 or 12, characterized in that the conical holding wedges (21.1, 21.2, 21.3) may comprise a tapped hole (42) intended to receive an extraction tool.

14. Assembly according to claims 11 to 13, characterized in that the blade root (8) comprises conical grooves (22.1, 22.2, 22.3) having a shape complementary to the conical holding wedges (21.1, 21.2, 21.3).

15. Assembly according to any one of claims 11 to 14, characterized in that the blade root (8) comprises a central wall (45) ensuring separation of the conical holding wedges (21.1, 21.2, 21.3) arranged on either side of said central wall (45).

16. Assembly according to claim 2, characterized in that it comprises at least one holding wedge (21) constituted by a carriage (48) movable in translation relative to the blade pivot (9), and perpendicular to the direction of longitudinal extension (D2) of the blade root (8), having an inclined face (49) intended to come to bear against a face of the blade root (8).

Images