BLOWER MODULE BLADE LOCKING SYSTEM VIA CLAMPING LEVER

Abstract

The invention relates to a module (10) for an aircraft turbomachine test bench comprising: - a hub (11) comprising two coaxial annular elements (13.1, 13.2) fixed to each other and defining between them at least one blade root housing (15), - at least one blade equipped with a blade root (19) disposed inside the blade root housing (15), - said module (10) comprising a locking system (21) in the position of the blade (12) comprising a clamping lever (24) configured such that tightening the fastening member (30) causes the clamping lever (24) to pivot around the first end portion (27.1) bearing against a bottom of the cavity (28), so that the central portion (26) of the clamping lever (24) clamps the blade root (19) against the hub (11) to immobilize the blade in a desired angular position. Figure 4a

Description

Title of the invention: LOCKING SYSTEM FOR A BLADE OF A BLOWER MODULE BY MECHANISM OF A CLAMPING LEVER

[0001] The present invention relates to a locking system for a blower module blade using a clamping lever. The invention finds a particularly advantageous, but not exclusive, application with a blower rotor module.

[0002] In a manner known per se, a turbomachine fan compresses the air entering the engine. A large portion of this air constitutes the secondary flow, and the other portion constitutes the primary flow. The latter 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] Fig. 1 shows a test machine 1 for a test bench 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, and a downstream flow channel 6.

[0004] 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 then returns the airflow, accelerated by the rotor module 4, to the X-axis of the motor.

[0005] 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. These operations must be able to be carried out as quickly as possible without having to disassemble the fully instrumented machine.

[0006] Documents FR2992347 and FR2003206 describe hubs equipped with variable-pitch blades intended for use in a turbomachine propelling an aircraft. However, existing devices are not entirely satisfactory because, in addition to being complex, they do not guarantee optimal mechanical strength of the parts and the assembly at all operating regimes of the turbomachine.

[0007] The invention aims to effectively remedy the aforementioned drawbacks by proposing a module for an aircraft turbomachine test bench comprising: - a hub comprising two coaxial annular elements fixed to each other and defining between them at least one blade foot housing, - at least one blade fitted with a blade foot located inside the blade foot housing, - said module includes a blade position locking system comprising: - a clamping lever comprising: a central portion designed to bear against one end face of the blade foot, a first end portion intended to be inserted into a cavity made in one of the annular elements, and a second end portion provided with a hole for the passage of a fastening element inserted inside a through opening made in the other annular element, said fastening element being intended to cooperate with a clamping nut, - in such a way that tightening the fastening element causes the clamping lever to pivot around the first end portion resting against a bottom of the cavity, so that the central portion of the clamping lever clamps the blade foot against the hub to immobilize the blade in a desired angular position.

[0008] The invention thus makes it possible to easily modify the angular position of the blade during the test without having to dismantle the test machine. The invention also preserves the aerodynamic profile of the flow regardless of the blade's position, vibrations, or internal displacements due to pumping or transient flow phenomena during a change in position. In the event of blade breakage, the invention also facilitates in-situ dismantling. The invention also has the advantage of being a simple solution to implement, requiring a minimum number of parts.

[0009] According to one embodiment of the invention, the clamping nut is rotationally linked with the clamping lever.

[0010] According to one embodiment of the invention, the clamping nut is disposed inside a notch made in the clamping lever, the clamping nut and the notch being configured so as to prevent rotation of the clamping nut inside the notch during a rotation of a corresponding fastening member.

[0011] According to one embodiment of the invention, the clamping nut has two flats which each bear against a corresponding lateral face of the notch.

[0012] According to one embodiment of the invention, the fastening member is blocked in translation inside the through opening.

[0013] According to one embodiment of the invention, a locking member is inserted inside a through hole made in the hub so as to open into the inside of a groove made in the fixing member.

[0014] According to one embodiment of the invention, the locking member extends perpendicularly with respect to the fixing member.

[0015] According to one embodiment of the invention, the fastening member is a screw equipped with a head positioned inside the through opening, so that an external face of the head is flush with an external face of the hub.

[0016] According to one embodiment of the invention, a retaining wall made in the blade foot housing is inserted inside a circumferential groove made in the blade foot.

[0017] According to one embodiment of the invention, said module consists of a blower rotor module.

[0018] 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:

[0019] [Fig-1] Fig. 1, already described, is a schematic longitudinal cross-sectional view of a test machine with which the invention is implemented;

[0020] [Fig.2] Fig.2 is a perspective view of a blower module for a bench aircraft turbomachine test according to the present invention;

[0021] [Fig.3] Fig.3 is an exploded perspective view of a module hub blower equipped with a system according to the invention for locking a blade in position;

[0022] [Fig.4a][Fig.4b] Figures 4a and 4b are cross-sectional views of the system according to the invention for locking a blade in position respectively in a locked state and in an unlocked state;

[0023] [Fig. 5] Fig. 5 is a top view of a rotation-locking device for a tightening nut of a locking system in position of a blade according to the present invention;

[0024] [Fig. 6] Fig. 6 is a perspective and cross-sectional view of a stopping device. translation of a fixing screw intended to cooperate with a clamping nut of a locking system according to the invention of a blade in position.

[0025] It should be noted that, in the figures, 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.

[0026] Figure 2 shows a fan module 10 for an aircraft turbomachine test bench comprising an annular hub 11 having an axis XI and a plurality of blades 12. The fan module 10 is a rotor module. Alternatively, the fan module 10 may be a rectifier module.

[0027] The hub 11 comprises two coaxial annular elements 13.1, 13.2 fixed to each other and defining between them housings 15 for receiving blade feet 19. distinguishes, by reference to a direction of circulation of an airflow generated by the blower in operation, an upstream annular element 13.1 and a downstream annular element 13.2. Thus, a portion of a dwelling 15 is delimited by the upstream annular element 13.1 and a complementary portion of the dwelling 15 is delimited by the downstream annular element 13.2.

[0028] Alternatively, the annular hub 11 may be a monobloc hub formed from a single annular element.

[0029] A blade foot housing 15 includes a retaining wall 16, as shown in Figures 3, 4a, and 4b. The collar-shaped retaining wall 16 originates from an inner face of the housing 15 and extends radially from the inner face of the housing 15 towards the center of the housing 15. The retaining wall 16 is formed partly in a portion of the housing 15 of the upstream annular element 13.1 and partly in a portion of the housing 15 of the downstream annular element 13.2.

[0030] The blades 12 extend radially outward along their Y-axis from the hub 11. The blades 12 are regularly spaced at an angle around a circumference of the hub 11. Each blade 12 has a generally cylindrical blade root 19 designed to be positioned inside a correspondingly shaped blade root housing 15. The retaining wall 16 formed in the blade root housing 15 is inserted into a circumferential groove 20 formed in the blade root 19 to provide radial support for the blade root 19.

[0031] As can be seen in Figures 3, 4a, and 4b, a locking system 21 in the position of the blade 12 allows, in an unlocked state, a rotation of the blade foot 19 inside a corresponding housing 15 around the Y axis so as to select a desired angular position of the blade 12 for a test and in a locked state to immobilize the blade 12 inside the housing 15 in the desired angular position.

[0032] To this end, as illustrated in [Fig. 3], the locking system 21 comprises a clamping lever 24 having a central portion 26 designed to bear against an end face 22 of the blade foot 19. The central portion 26 has an annular shape. The end face of the blade foot 19 is radial with respect to the axis XI of the hub 11. In the locked position, the clamping lever 24 extends along a plane substantially perpendicular to the axis Y of the blade 12.

[0033] The clamping lever 24 also includes a first end portion 27.1 intended to be inserted inside a cavity 28 formed in the downstream annular element 13.2. The cavity 28 is formed in an internal face of the portion of the housing 15 of the downstream annular element 13.2. The cavity 28 opens axially into the housing 15.

[0034] The clamping lever 24 comprises a second end portion 27.2 equipped with a A through hole 25 for a fastener 30. The fastener 30 is inserted into a through opening 31 made in the upstream annular element 13.1. The fastener 30 is intended to cooperate with a clamping nut 4L

[0035] The first end portion 27.1 and the second end portion 27.2 are arranged on either side of the central portion 26. The first end portion 27.1 and the second end portion 27.2 extend outwards from the central portion 26.

[0036] Alternatively, the structure may be reversed, i.e. the cavity 28 is made in an internal face of the portion of the housing of the upstream annular element 13.1 and the fixing member 30 is disposed inside a through opening 31 made in the downstream annular element 13.2.

[0037] The fastening member 30 is fixed against translation within the through-hole 31 formed in the hub 11. The through-hole 31 has a radial orientation axis with respect to the axis XI of the hub 11. Preferably, the fastening member 30 is a screw with a head 32 located inside the through-hole 31, such that an external face of the head 32 is flush with an external face of the hub 11. This ensures an optimal duct profile due to the continuity of the surface between the screw head 32 and the blade root 19. This prevents any interference with the aerodynamic flow of the duct. Alternatively, the fastening member 30 may be in the form of a rivet or a stud.

[0038] As can be seen in [Fig. 6], in order to ensure translational locking of the fastener 30, a locking member 34, such as a screw or a pin, is inserted into a through hole 35 made in the hub 11 so as to open into a groove 38 of a fastener screw 30. The groove 38 extends between the head 32 of the fastener screw 30 and a portion of the stop 39. The locking member 34 extends perpendicularly with respect to the fastener 30.

[0039] As can be seen in figures 4a and 4b, the fastening member 30 is inserted inside a through hole 25 so as to cooperate with a corresponding clamping nut 41 linked in rotation with the clamping lever 24. The clamping nut 41 has a tapped opening provided with a self-locking insert thread cooperating with the thread of a corresponding fastening member 30.

[0040] As can be seen in [Fig. 5], the clamping nut 41 is disposed inside a notch 42 formed in the second end portion 27.2 of the clamping lever 24. The clamping nut 41 and the notch 42 are configured to prevent rotation of the clamping nut 41 inside the notch 42 when a corresponding fixing screw 30 is rotated. To this end, the clamping nut 41 has two flats 43, each of which bears against a corresponding lateral face of the notch 42.

[0041] The operation of the locking system 21 is described below with reference to [Fig.4a] and 4b. The clamping lever 24 is held in the unlocked state by the fixing member 30 and the clamping nut 41.

[0042] As illustrated by [Fig.4a], once the angular position of the blade 12 has been chosen, tightening the fixing member 30 by rotation along arrow Fl using a tool causes, due to an upward movement of the clamping nut 41 (i.e. in the direction of the blade foot 19), a pivoting along arrow F2 of the clamping lever 24 around the first end portion 27.1 bearing against a bottom of the cavity 28. The central portion 26 of the clamping lever 24 approaches the blade foot 19 until it clamps the blade foot 19 against the hub 11 to immobilize the blade 12 in a desired angular position. In this case, the end of the blade foot 19 is then held tightly between the central portion 26 of the clamping lever 24 and the retaining wall 16. The clamping lever 24 is able to pivot around a pivot axis X2 located at the point of a support zone between the first end portion 27.1 and the bottom of the cavity 28.The pivot axis X2 extends in a substantially ortho-radial direction with respect to the axis XI of the hub 11.

[0043] Advantageously, the end face 22 of the blade foot 19 has a rounded shape along a radius of curvature and the clamping lever 24 has a contact face with the blade foot 19 of frustoconical shape, so that the support between the clamping lever 24 and the blade foot 19 is a linear support.

[0044] To modify the angular position of a blade 12, the clamping lever 24 is slightly loosened. For this purpose, as illustrated in [Fig. 4b], the fastening member 30 is loosened using a tool along arrow F3 with a direction of rotation opposite to that of arrow FL. Due to a downward displacement of the clamping nut 41, i.e., in a direction opposite to that of the blade root 19, this causes the clamping lever 24 to pivot along arrow F4 around the first end portion 27.1, which bears against the bottom of the cavity 28. The central portion 26 of the clamping lever 24 then moves away from the blade root 19. The blade 12 is then free to rotate. It is thus possible to rotate the blade 12 around the Y-axis along arrow F5. The orientation of the blades 12 is thus modified according to the desired angle. Once the angular position of the blade 12 is chosen, the clamping lever 24 is tightened, as explained above.

[0045] The operations of handling the blade 12 and tightening or loosening the fixing screws 30 can be carried out by a human operator or a robot.

[0046] The invention thus allows for a rapid adjustment of the blade alignment 12 between two tests. Furthermore, in the event of a blade 12 breaking, dismantling can be carried out in situ, resulting in a significant time saving.

[0047] Of course, the different characteristics, variants and / or embodiments of the present invention can be associated with each other in various combinations as long as they are not incompatible or mutually exclusive.

[0048] 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

Claims

1. Module (10) for an aircraft turbomachine test bench comprising: - a hub (11) comprising two coaxial annular elements (13.1, 13.2) fixed to each other and defining between them at least one blade root housing (15), - at least one blade (12) provided with a blade root (19) arranged inside the blade root housing (15), said module (10) comprising a locking system (21) in position of the blade (12) comprising: - a clamping lever (24) comprising: a central portion (26) intended to bear against an end face (22) of the blade root (19), a first end portion (27.1), and a second end portion (27.2) provided with a passage hole (25) for a fixing member (30) inserted inside of a through opening made in one of the annular elements (13.1, 13.2), characterized in that the first end portion (27.1) is inserted inside a cavity (28) made in the other annular element (13.1, 13.2) and in that said fixing member (30) is intended to cooperate with a tightening nut (41), in such a way that tightening of the fixing member (30) causes pivoting of the tightening lever (24) around the first end portion (27.1) bearing against a bottom of the cavity (28), so that the central portion (26) of the tightening lever (24) tightens the blade root (19) against the hub (11) to immobilize the blade (12) in a desired angular position.

2. Module according to claim 1, characterized in that the clamping nut (41) is rotationally connected to the clamping lever (24).

3. Module according to claim 2, characterized in that the clamping nut (41) is arranged inside a notch (42) made in the clamping lever (24), the clamping nut (41) and the notch (42) being configured so as to prevent rotation of the clamping nut (41) inside the notch (42) during rotation of a corresponding fixing member (30).

4. Module according to claim 3, characterized in that the clamping nut (41) has two flats (43) which each bear against a corresponding lateral face of the notch (42).

5. Module according to any one of claims 1 to 4, characterized in that the fixing member is locked in translation inside the through opening (31).

6. Module according to claim 5, characterized in that a locking member (34) is inserted inside a through hole (35) made in the hub (11) so as to open inside a groove (38) made in the fixing member (30).

7. Module according to claim 6, characterized in that the locking member (34) extends perpendicularly to the fixing member (30).

8. Module according to any one of claims 1 to 7, characterized in that the fixing member (30) is a screw provided with a head (32) arranged inside the through opening (31), so that an external face of the head (32) is flush with an external face of the hub (11).

9. Module according to any one of claims 1 to 8, characterized in that a retaining wall (16) produced in the blade root housing (15) is inserted inside a circumferential groove (20) produced in the blade root (19).

10. Module according to any one of claims 1 to 9, characterized in that it is constituted by a fan rotor module.

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