BLOWER MODULE BATTERY LOCKING SYSTEM WITH DOUBLE CLAMPING NUTS

Abstract

The present 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), - at least one blade (12), - said module (10) comprising a locking system (21) in the position of the blade (12) comprising: - a pivot flange (24) intended to bear against an end face of the blade foot (19), - at least two fastening members (30) each blocked in translation inside a through opening (31) made in the hub (11), - each fastening member (30) cooperating with a corresponding clamping nut (41) rotationally linked with the pivot flange (24), so that tightening the fastening members (30) ensures that the blade foot (19) is clamped against the hub (11) to immobilize the blade (12) in a desired angular position. Figure 3

Description

Title of the invention: BLADES LOCKING SYSTEM FOR A BLOWER MODULE BY DOUBLE CLAMPING NUTS

[0001] The present invention relates to a blade locking system for a blower module using a double clamping nut. The invention finds a particularly advantageous, but not exclusive, application with a blower straightening 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 machine, since the latter is fully instrumented.

[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 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 comprising a locking system in the blade position including: - a pivot flange designed to bear against one end face of the blade foot, - at least two fastening elements, each blocked against translation inside a through opening made in the hub, - each fastening element cooperating with a corresponding clamping nut rotationally linked with the pivot flange, so that tightening the fastening elements ensures that the blade foot is clamped 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 end face of the blade foot has a rounded shape along a radius of curvature and the pivot flange has a contact face with the blade foot of frustoconical shape so that the support between the pivot flange and the blade foot is a linear support.

[0010] According to one embodiment of the invention, a clamping nut is disposed inside a notch made in the pivot flange, 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, a clamping nut has two flats each bearing against a corresponding lateral face of the notch.

[0012] According to one embodiment of the invention, a locking member is inserted inside a through opening made in the hub so as to open into the inside of a groove made in a fixing member.

[0013] According to one embodiment of the invention, the locking member extends perpendicularly with respect to the fixing member.

[0014] According to one embodiment of the invention, the fastening members are screws each provided with a head disposed inside the through opening, so that an external face of the head is flush with an external face of the hub.

[0015] According to one embodiment of the invention, a retaining wall made in the housing of The awl foot is inserted inside a circumferential groove made in the awl foot.

[0016] According to one embodiment of the invention, the pivot flange comprises a central portion intended to bear against the blade foot and two lugs extending in projection relative to the central portion, each lug comprising a hole for the passage of a fastening member.

[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 longitudinal cross-sectional view of a machine test 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] The [Fig.3] is an exploded perspective view of a blower module hub equipped with a locking system in position of a double clamping nut blade according to the present invention;

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

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

[0024] [Fig.6] The [Fig.6] is a perspective and cross-sectional view of a translational stop device for fixing screws intended to cooperate with the clamping nuts of a locking system in position of a blade according to the invention;

[0025] [Fig.7] Fig.7 is a schematic representation of the different mechanical bonds mechanical connections between the different components of a locking system in the position of a blade according to the invention.

[0026] 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.

[0027] Figure 2 shows a blower module 10 for a turbomachine test bench of an aircraft 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.

[0028] 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 roots. With reference to the direction of airflow generated by the operating blower, an upstream annular element 13.1 and a downstream annular element 13.2 are distinguished. Thus, a portion of a housing 15 is delimited by the upstream annular element 13.1 and a complementary portion of the housing 15 is delimited by the downstream annular element 13.2.

[0029] Alternatively, the annular hub 11 may be a monobloc hub formed from a single annular element.

[0030] 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.

[0031] 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 ensure radial retention of the blade root 19.

[0032] 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.

[0033] For this purpose, the locking system 21 includes a pivot flange 24 intended to bear against an end face 22 of the blade foot 19. The end face of the blade foot 19 is a radial end face with respect to the axis XI of the hub 11.

[0034] The pivot flange 24 extends along a plane normal to the Y axis of the blade 12. The pivot flange 24 has two through holes 25 for the passage of fastening elements 30.

[0035] The pivot flange 24 comprises a central portion 26 of annular shape intended to to rest against the foot of the awl 19 and two ears 27 extending outward from the central portion 26, as shown in [Fig.3]. Each ear 27 has a hole 25 for the passage of a fixing element.

[0036] At least two fastening members 30 are each blocked against translation within a through opening 31 made in the hub 11. Each through opening 31 has a radial orientation axis with respect to the axis XI of the hub 11. A first fastening member 30 is disposed within a through opening 31 made in the upstream annular element 13.1. A second fastening member 30 is disposed within a through opening 31 made in the downstream annular element 13.2.

[0037] Preferably, the fastening members 30 are screws, each with a head disposed inside the corresponding through opening 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 heads 32 and the blade root 19. This prevents any interference with the aerodynamic flow of the duct. Alternatively, the fastening members 30 may be in the form of pins or studs.

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

[0039] As can be seen in Figures 4a and 4b, each fixing screw 30 is inserted into a through hole 25 so as to cooperate with a corresponding clamping nut 41, which is rotationally linked to the pivot flange 24. Each clamping nut 41 has a tapped opening that cooperates with the thread of a corresponding fixing screw 30. Advantageously, the tapped opening of a clamping nut 41 is provided with a self-locking insert thread.

[0040] As can be seen in [Fig. 5], a clamping nut 41 is disposed inside a notch 42 formed in the pivot flange 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, a clamping nut 41 has two flats 43, each bearing against a corresponding lateral face of the notch 42. A notch 42 is formed in a lug 27 of the corresponding flange 24.

[0041] The operation of the locking system 21 is described below. The pivot flange 24 is held by the double connection between the fixing screws 30 and the clamping nuts. 41. Once the angular position of the blade 12 has been selected, the fixing screws 30 are tightened to ensure that the blade foot 19 is clamped against the hub 11, thus immobilizing the blade 12 in the desired angular position, as shown in [Fig. 4a]. For this purpose, a step-by-step assembly of the fixing screws 30 allows translation of the pivot flange 24 towards the end face 22 of the blade foot 19.

[0042] Advantageously, the end face 22 of the blade foot 19 has a rounded shape along a radius of curvature RI and the pivot flange 24 has a contact face with the blade foot 19 of frustoconical shape so that the support between the pivot flange 24 and the blade foot 19 is a linear support.

[0043] To change the angular position of a blade 12, the pivot flange 24 is slightly loosened to allow the blade 12 to be rotated about the Y-axis along the arrow Fl, as shown in [Fig. 4b]. This changes the inclination of the blades 12 to the desired angle. Once the angular position of the blade 12 is selected, the pivot flange 24 is tightened.

[0044] 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.

[0045] 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.

[0046] Fig. 7 is a schematic representation of the various mechanical links between the different components of the locking system 21 in the position of a blade 12 according to the invention.

[0047] The L1 connection between the blade foot 19 and the hub 11 is a pivot connection.

[0048] The L2 and L3 connections between the fixing screws 30 and the hub 11 are respectively a sliding pivot joint and a plane-to-plane contact joint.

[0049] The L4 connection between the fixing screws 30 and the clamping nuts 41 is a helical connection.

[0050] The L5 connection between the pivot flange 24 and the blade foot 19 is a sphero-conical connection.

[0051] The L6 and L7 links between the pivot flange 24 and the clamping nuts 41 are respectively a cylinder-to-cylinder contact link and a plane-to-plane contact link.

[0052] 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.

[0053] 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 framework of the present invention and in particular all combinations of the different modes of operation described above, which can be taken separately or in association.

Claims

Demands

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), said hub (11) having an axis (XI), - at least one blade (12) provided with a blade root (19) disposed inside the blade root housing (15), said blade (12) having an axis (Y), - said module (10) comprises a locking system (21) in the position of the blade (12) comprising: - a pivot flange (24) intended to bear against an end face (22) of the blade root (19), - at least two fastening members (30) each blocked against translation inside a through opening (31) made in the hub (11), - each fastening member (30) cooperating with a corresponding clamping nut (41) rotationally linked with the pivot flange (24),so that tightening the fastening members (30) ensures that the blade foot (19) is clamped against the hub (11) to immobilize the blade (12) in a desired angular position, characterized in that the end face of the blade foot (19) is a radial end face with respect to the axis (XI) of the hub (11), - the pivot flange (24) extending along a plane normal with respect to the axis (Y) of the blade (12).

2. Module according to claim 1, characterized in that the end face (22) of the blade foot (19) has a rounded shape along a radius of curvature (RI) and the pivot flange (24) has a contact face with the blade foot (19) of frustoconical shape so that the support between the pivot flange (24) and the blade foot (19) is a linear support.

3. Module according to claim 1 or 2, characterized in that a clamping nut (41) is disposed inside a notch (42) made in the pivot flange (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 fastening member (30).

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

5. Module according to any one of claims 1 to 4, characterized in that a locking member (34) is inserted inside a through opening (35) made in the hub (11) so as to open into a groove (38) made in a fixing member (30).

6. Module according to claim 5, characterized in that the locking member (34) extends perpendicularly with respect to the fixing member (30).

7. Module according to any one of claims 1 to 6, characterized in that the fastening members (30) are screws each having a head (32) disposed inside the through opening (31), so that an external face of the head (32) is flush with an external face of the hub (11).

8. Module according to any one of claims 1 to 7, characterized in that a retaining wall (16) made in the blade foot housing (15) is inserted inside a circumferential groove (20) made in the blade foot (19).

9. Module according to any one of claims 1 to 8, characterized in that the pivot flange (24) has a central portion (26) intended to bear against the blade foot (19) and two lugs (27) extending in projection from the central portion (26), each lug (27) having a passage hole (25) for a fastening member (30).

10. Module according to any one of claims 1 to 9, characterized in that it consists of a blower rotor module.

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