Angular adjustment assembly equipped with a worm screw and a fixing nut for an adjustable-orientation blade and associated adjustment method

Abstract

Worm gear angular adjustment assembly for a variable pitch blade and associated adjustment method. One aspect of the invention relates to an angular adjustment assembly (20) for an adjustable pitch blade (210) comprising: a hub (200), a blade (210) mounted for rotation within the hub, and a blade rotation adjustment device. The adjustment device comprises: a worm gear (242) including a threaded rod (243) received in the hub and a blade base (220), and a head (244), a retaining nut (250) mounted for rotation within a machined hole (222) in the base and including a tapped hole (252) receiving the threaded rod, the retaining nut being mounted for translational movement on the threaded rod, an axial locking piece (266) for the worm gear, a means for locking the worm gear against rotation, and a means for rotating the worm gear. Figure to be published with the abbreviation: Figure 2

Description

Title of the invention: Angular adjustment assembly equipped with a worm screw and a fixing nut for an adjustable-orientation blade and associated adjustment method. TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of aircraft turbomachinery and test machines for the development of aircraft turbomachinery.

[0002] The present invention relates to an angular adjustment assembly for an adjustable-slope blade of a turbomachine or turbomachine test machine. It also relates to a turbomachine and a turbomachine test machine comprising such an angular adjustment assembly, as well as a method for adjusting such an angular adjustment assembly. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Conventionally, aircraft turbomachinery incorporates adjustable-pitch blades, also called variable-pitch or pivoting blades. Adjustable-pitch blades are configured to pivot around their axis of rotation in order to adjust their angular position (their angle of attack) relative to the airflow passing through them and thus optimize the airflow within the turbomachine.

[0004] There are stator stages of variable-pitch blades arranged between the moving wheels of turbomachinery compressors. These can also be flow straightening blades arranged downstream of the fan, called outlet guide vanes or OGVs (Outlet guide vanes).

[0005] Such blades are mounted on a stator housing and can be pivoted during engine operation, thus optimizing their action according to engine speed and flight conditions. Since the turbomachine's performance depends on the accuracy of the angular positioning of these blades relative to the housing, the adjustment of the angular position must be rapid, precise, reliable, and repeatable.

[0006] In the prior art, the adjustable-angle blades are extended at their outer end by a radial control rod that passes through an opening in the outer casing. Control rods are attached laterally to the free ends of these control rods and are connected at their other end to a rotating ring located outside the casing. An electrical, pneumatic, or hydraulic servo system automatically controls the rotation of the ring according to the operating conditions, which causes the rods to pivot and thus changes the inclination of the adjustable-angle blades.

[0007] For this system to be functional, the coupling between the control rod and the The connecting rod of a blade must be precise in addition to having to withstand significant torques. Furthermore, the adjustment of the blade's orientation relative to the connecting rod during assembly must be particularly fine.

[0008] An objective of the invention is to provide a mechanically simplified alternative angular adjustment system for variable pitch blades, usable in a turbomachine, which is fast, precise, reliable and repeatable.

[0009] Adjustable-orientation blades are also used in test machines for developing aircraft turbomachinery. These test machines allow testing the aerodynamic and acoustic behavior of the various turbomachine components, and in particular, determining the optimal angular positioning of the rotor blades and stator blades to obtain the best possible performance.

[0010] The test machines therefore classically include adjustable orientation blades in order to be able to simulate a precise angular positioning of these blades and / or test different positionings according to the result of the tests.

[0011] Currently, in testing machines, the angular adjustment of adjustable-orientation blades is done manually by an operator using complex tools to measure the blade displacement and thus position it with the desired angle of adjustment. This operation is lengthy and meticulous and must be performed blade by blade by an experienced operator.

[0012] An objective of the invention is to propose an alternative angular adjustment system for variable pitch blades, usable in a test machine, which is simple, fast, precise, reliable and repeatable. Summary of the invention

[0013] The invention offers a solution to the problems mentioned above by proposing an angular adjustment set for a blade with adjustable orientation of a turbomachine or turbomachine test machine of axis Al having a particular architecture.

[0014] A first aspect of the invention relates to an angular adjustment assembly comprising: • a hub comprising a first face and a second face opposite each other along the axis Al, • an adjustable-angle blade comprising a base and a blade extending radially from the base, the base of the adjustable-angle blade being mounted to rotate freely in the hub with respect to an axis A2 perpendicular to the axis Al; and • a device for adjusting the rotation of the blade with adjustable orientation around axis A2,

[0015] The adjustment device comprises: • an endless screw with axis A3 parallel to the axis Al, comprising: • a threaded rod received in a through hole in the hub extending from its first face to its second face, and in a recess in the base of the adjustable-orientation blade, the threaded rod being free in translation along a direction T2 perpendicular to the axes A2 and A3, and • a head resting against the first face of the hub, • a fixing nut having a circular cross-section, the fixing nut being mounted for rotational movement in a hole fitted to the base with respect to an axis A4 parallel to axis A2 and perpendicular and intersecting axis A3, and comprising a tapped hole with axis A3 receiving the threaded rod of the worm screw, the fixing nut being mounted for translational movement on the threaded rod of the worm screw, • an axial locking piece for the worm screw with respect to the hub, • a means of locking the worm gear against rotation relative to the hub, And • a means of rotating the worm screw.

[0016] Such an angular adjustment set is usable both in an aircraft turbomachine and in an aircraft turbomachine test machine.

[0017] In a turbomachine, the angular control assembly can, for example, allow the angular position of the outlet guide vanes or the adjustable orientation vanes of the compressors to be adjusted in order to adapt their angular positioning to the engine speed and flight conditions and thus optimize the operation of the turbomachine.

[0018] In a test machine, the angular adjustment assembly can be used to adjust the angular position of any blade whose angular orientation has been designed to be adjustable in the test machine (this blade can be fixed once installed in a turbomachine). Different angular positions of this blade can thus be tested using the test machine, and an aerodynamically optimal angular position (an optimal pitch angle) can be defined for subsequent reproduction in the turbomachine to improve performance.

[0019] The invention provides an angular adjustment assembly by combining a worm gear with a fixing nut that is reliable and mechanically simple. Such an angular adjustment assembly allows the angular position of the adjustable-slope blade to be adjusted quickly and easily, without the need to disassemble any parts beforehand.

[0020] According to a first embodiment of the adjustment device, the fixing nut is a cylinder with axis A4.

[0021] According to a second embodiment of the adjustment device, the fixing nut is a sphere.

[0022] Advantageously, the locking piece is arranged to bear against the first face of the hub and includes a housing in which the worm gear head is free to translate along the face, in the direction T2. ​​Such a feature allows the base of the adjustable-orientation blade to rotate relative to the hub and thus the angular adjustment of the adjustable-orientation blade.

[0023] Preferably, the locking means comprises a nut arranged at one end of the threaded rod of the worm screw, opposite the second face of the hub

[0024] Advantageously, the recess in the base of the adjustable-orientation blade is open in a direction perpendicular to axes A3 and A4. This feature allows the base of the adjustable-orientation blade to rotate about axis A3 without hitting the threaded rod of the worm gear.

[0025] A second aspect of the invention relates to an angular adjustment system for a ring of adjustable-orientation blades of a turbomachine or turbomachine test machine, which includes an angular adjustment assembly according to the first aspect of the invention for each of the adjustable-orientation blades.

[0026] Advantageously, such an adjustment system may further include a device for synchronizing the rotation of the threaded rods of the worm screws of the angular adjustment assemblies.

[0027] The synchronizing device allows the rotation of the threaded rods of all the worm gears, and therefore the movement of all the fixing nuts of the various angular adjustment assemblies, to be coordinated so that they are actuated simultaneously and in the same way. The angular position of each adjustable-orientation blade of the blade ring can thus be modified synchronously, that is, simultaneously and in the same way.

[0028] A third aspect of the invention relates to an aircraft turbomachine comprising at least one angular adjustment assembly according to the first aspect of the invention.

[0029] A fourth aspect of the invention relates to a turbomachine test machine comprising at least one angular adjustment assembly according to the first aspect of the invention.

[0030] A fifth aspect of the invention relates to a method for angularly adjusting a variable-pitch blade, carried out by means of an angular adjustment assembly and comprising the following steps: • unlocking the worm gear by means of the locking mechanism of the adjustment device, • rotation of the threaded rod of the worm gear of the adjusting device until this that at a desired position of the blade with adjustable orientation relative to the hub, and • locking of the worm screw by means of the locking mechanism of the adjustment device.

[0031] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0032] Other advantages and features of the invention will become apparent from the following description, illustrated by the figures in which:

[0033] [Fig. 1] is a partial cross-sectional view of a test machine comprising a angular adjustment assembly, according to the invention;

[0034] [Fig.2] is a longitudinal front section of an example of the adjustment assembly angular along a cutting plane II-II of the [Fig.5] comprising an adjustment device, according to the invention;

[0035] [Fig.3] is a longitudinal top section of the angular adjustment assembly according to a III-III plan of [Fig.2], in a first position of the adjustment device;

[0036] [Fig.4] is a view analogous to that of [Fig.2], in a second position of the adjustment device;

[0037] [Fig.5] is a side cross-section of the angular adjustment assembly according to a VV plan of [Fig.2]. DETAILED DESCRIPTION

[0038] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0039] In the description, the terms "upstream" and "downstream" are defined with respect to the normal direction of gas flow (from upstream to downstream) through a turbomachine or turbomachine test machine. Furthermore, the terms "turbomachine axis" or "test machine axis" refer to the axis of rotation of the turbomachine or test machine rotor, this axis being designated Al in the figures.

[0040] Fig. 1 represents a turbomachine test machine 10 configured to simulate an aircraft turbomachine and test its components under different aerodynamic conditions in order to study their performance.

[0041] The test machine 10 according to an example such as shown in [Fig. 1] comprises: • a blower 12 having a ring of movable blades 14, • a rectifier stator ring 16 arranged downstream of the ring of 14 movable blades and comprising: • 200 hubs, and • 210 OGV type adjustable pitch blades (one of which has been (framed in figure 1) each being mounted to rotate freely in one of the hubs 200, with respect to an axis A2 perpendicular to the axis Al, and • at least one set of angular adjustment 20 of one of the adjustable orientation blades 210.

[0042] As shown in [Fig.1], an angular adjustment assembly 20 is advantageously installed for each of the adjustable-orientation blades 210. All the angular adjustment assemblies 20 of the rectifier stator ring 16 can advantageously be associated with a synchronizing device and together form an angular adjustment system 18 for the rectifier stator ring 16 of adjustable-orientation blades 210.

[0043] Such an angular adjustment assembly 20 can also be put in place in a tur-bomachine.

[0044] According to an example such as shown in Figures 2 to 5, each angular adjustment assembly 20 comprises: • a single hub 200 comprising a first face 202A and a second face 202B opposed to each other along the axis Al and an external face 203 connecting the first and second faces 202A, 202B to each other, • a single adjustable-orientation blade 210 comprising: • a 220 base mounted for rotational mobility within the 200 hub relative to the A2 axis, and • a blade 230 extending radially from the base, • a device for adjusting the rotation of the blade with adjustable orientation 210 around the axis A2.

[0045] The adjustable-orientation blade 210 is mounted freely to rotate around the axis A2 so as to modify the angular orientation of the blade 230 relative to the hub 200 according to several positions of the blade 230.

[0046] The base 220 of the adjustable-axis blade 210 is engaged in a housing 206 of the hub 200. As shown in [Fig. 2], the base 220 comprises two coaxial cylindrical portions, a first portion 220A extending from its surface in contact with the blade 230 along axis A2 and before axis A3, and a second portion 220B extending from the first portion 220A along axis A2 and beyond axis A3. The difference in diameter between the first and second portions 220A, 220B of the base 220 forms a shoulder.

[0047] The housing 204 of the hub 200 has a shape complementary to that of the base 220 and is open in the external face 203 of the hub 200. As shown in [Fig. 2], the housing 204 comprises two coaxial cylindrical portions, the first portion 204A extending from the external face 203 of the hub 200 along axis A2 and before axis A3 and a second portion 204B extending from the first portion 204A along axis A2 and beyond axis A3. The difference in diameter between the first and second portions 204A, 204B of housing 204 forms a collar.

[0048] In the engaged position of the base 220 of the adjustable-orientation blade 210 in the housing 204 of the hub 200, the first portion 220A of the base 220 is received in the first portion 204A of the hub 200, the second portion 220B of the base 220 is received in the second portion 204A of the hub 200 so that the collar of the housing 204 of the hub 200 is in contact with the shoulder of the base 220 of the adjustable-orientation blade 210 retaining longitudinally the adjustable-orientation blade 210 along the axis Al.

[0049] The hub 200 further includes a through hole 206 extending from its first face 202A to its second face 202B along an axis A3 parallel to the axis AL

[0050] The adjustable-orientation vane 210 further comprises: • a recess 224 (visible in [Fig. 5]) arranged in the second portion 220B of its base 220 and extending along the axis A3, • a fitted hole 222 arranged in the second portion 220B of its base 220 and extending along an axis A4 parallel to the axis A2 and perpendicular and intersecting the axis A3.

[0051] As shown in Figures 1 to 4, the recess 224 in the base 220 of the adjustable-axis blade 210 (represented by a dashed line) encompasses the portion of the threaded rod 243 of the worm gear 242 opposite the housing 220 and includes the retaining nut 250 of the adjustment device 240. More specifically, as shown in [Fig. 5], the recess 224 has a length along axis A4 greater than the diameter of the threaded rod 243 of the worm gear 242 of the adjustment device 240, so that the pivoting of the base 220 of the adjustable-axis blade 210 relative to axis A3 is not blocked by the worm gear 242. According to a particular example as shown in [Fig. 5], the recess 224 of the base 220 The adjustable-orientation 210 vane is opened in a direction perpendicular to axes A3 and A4.

[0052] The adjustment device 240 according to an example such as shown in Figures 2 to 5 comprises: • a worm screw 242 with axis of rotation A3 parallel to the axis Al, comprising: • a threaded rod 243 received in the through hole 206 of the hub 200, and in the recess 224 of the base 220 of the adjustable-orientation blade 210, the threaded rod 243 comprising a free end 246, and • a head 244 bearing against the first face 202A of the hub 200, • a fixing nut 250 having a circular cross-section and comprising a tapped hole 252 with axis A3 receiving the threaded rod 243 of the worm screw 242, • an axial locking piece 266 for the worm gear 242 relative to the hub 200, arranged to bear against the first face 202A of the hub 200 and includes a housing 268 into which the head 244 of the worm gear 242 is received, • a means for locking the worm gear 242 against rotation relative to the hub 200, comprising: • a nut 264 arranged at the free end 246 of the threaded rod 243 of the worm screw 240, and • a washer 262 arranged between the second face 202B of the hub 200 and the nut 264, and • a means for rotating the worm screw 242 formed by a clamping slot 248 arranged in the free end 246 of the threaded rod 243 of the worm screw 242.

[0053] As illustrated in [Fig. 2], the housing 268 of the locking piece 266 has a length along axis A4 substantially equal to the diameter of the head 244 of the worm screw 242. The length of the housing 268 may also be greater than that of the head 244 of the worm screw 242. As illustrated in [Fig. 4], the housing 268 of the locking piece 266 has a width greater than that of the head 244 of the worm screw 242.

[0054] In the raised position of the adjustment device 240 relative to the hub 200 and the adjustable-orientation blade 210: • The worm gear 242 is free to translate along a direction T2 perpendicular to axes A2 and A3 (visible in figures 2 and 3) such that: • the threaded rod 243 is free to move in translation within the through hole 206 of the hub 200 in the direction T2, and • the head 244 is free to translate within the housing 268 of the locking piece 266 in the direction T2, • The fixing nut 250 is mounted for rotational movement in the fitted hole 222 of the base 220 relative to the axis A4 (visible in Figures 2 and 5), and • the fixing nut 250 being mounted movably in translation on the threaded rod 243 of the worm screw 242 in a direction Tl parallel to the axis A3 (visible in figures 3 and 4),

[0055] The worm gear 242 of the adjustment device 240 is configured to rotate the adjustable-angle blade 210 around the axis A2 to adjust its angular position. Indeed, the rotation of the threaded rod 243 of the worm gear 242 around its axis A3 causes the fixing nut 242 to translate in the direction T1 and consequently the worm gear 242 to translate in the direction T2 and the adjustable-angle blade 210 to pivot around the axis A2.

[0056] According to a first example as shown in Figures 2 to 5, the fixing nut The adjusting device 240, 250, is a cylinder with axis A4, and the fitted hole 222 of the second portion 220B of the base 220 of the adjustable-orientation blade 210 has a cylindrical shape complementary to that of the retaining nut 250 and is open.

[0057] According to a second example not shown, the retaining nut 250 of the adjusting device 240 is a sphere, and the fitted hole 222 of the second portion 220B of the base 220 of the adjustable-orientation blade 210 has a spherical shape complementary to that of the retaining nut 250 and is open.

[0058] The tapped hole 252 of the fixing nut 250 of the adjusting device 240 has an internal thread configured to mesh with the threads of the threaded rod 243 of the worm screw 242.

[0059] In the locked position of the locking means 260 of the adjustment device 240 as shown in Figures 2 to 5: • the nut 264 is screwed in so that the washer is held against the second face 203 of the hub 200, and • the threaded rod 243 of the worm screw 242 is locked in pivoting around the axis A3 thus fixing the angular orientation of the blade 230 of the adjustable-orientation blade 210.

[0060] In the unlocked position of the locking means 260 of the adjustment device 240, not shown: • Nut 264 is unscrewed so that washer 262 is no longer in contact with the second face 203 of hub 200, • and the threaded rod 243 of the worm screw 242 is free to pivot around the axis A3.

[0061] Advantageously, the clamping slot 248 formed in the free end 246 of the threaded rod 243 of the worm gear 242 has a hollow shape complementary to the end of a tool configured to engage in it so as to rotate the worm gear 242. The clamping slot 248 may, for example, have a hollow hexagonal, cruciform, square, slotted, or star shape, complementary to that of a suitable wrench or screwdriver. Depending on the application, this tool may be manual or automated (by servomotor or other mechanical locking).

[0062] A method for angularly adjusting a blade with adjustable orientation 210 carried out by means of an angular adjustment assembly 20 comprises the following steps: • unlocking the worm gear 242 until the unlocked position of the locking means 260 of the adjustment device 240 in which the worm gear 242 is free to rotate relative to the axis A3, • insertion of the end of a tool into the clamping slot 248 of the threaded rod 243 of the worm screw 242 of the adjusting device 240, • rotation of the threaded rod 243 of the worm screw 242 (passage from [Fig.3] to the [Fig. 4]) causing: • the translation Tl of the fixing nut 242, • the rotation of the fixing nut 242 in the adjusted hole 222 of the base of the adjustable-orientation blade 210 around the axis A4, • the translation T2 of the worm gear 242, • the pivoting PI of the base 220 of the adjustable-slope blade 210 in the housing 204 of the hub around the axis A2 until the desired pitching angle of the adjustable-slope blade 210 relative to the hub 200 is reached, and locking of the worm screw 242 until the locked position of the locking means 260 of the adjusting device 240 according to which the worm screw 242 is blocked in rotation relative to the axis A3.

Claims

Demands

1. Angular adjustment assembly (20) of an adjustable-slope blade (210) of a turbomachine or turbomachine test machine (10) with an Al axis, the angular adjustment assembly (18) comprising: - a hub (200) comprising a first face (202A) and a second face (202B) opposite each other along the axis Al, - an adjustable-angle blade (210) comprising a base (220) and a blade (230) extending radially from the base (220), the base (220) of the adjustable-angle blade (210) being mounted to rotate freely in the hub (200) with respect to an axis A2 perpendicular to the axis Al; and - a device for adjusting the rotation (240) of the adjustable-orientation blade (210) around axis A2, characterized in that the adjustment device (240) comprises: - a endless screw (242) with axis A3 parallel to axis Al comprising: • a threaded rod (243) received in a through hole (206) of the hub (200) extending from its first face (202A) to its second face (202B), and in a recess (224) of the base (220) of the adjustable-orientation blade (210), the threaded rod (243) being free in translation along a direction T2 perpendicular to the axes A2 and A3, and • a head (244) bearing against the first face (202A) of the hub (200), - a fixing nut (250) having a circular cross-section, the fixing nut (250) being mounted movably in rotation in a hole fitted (222) of the base (220) with respect to an axis A4 parallel to the axis A2 and perpendicular and intersecting the axis A3, and comprising a tapped hole (252) of axis A3 receiving the threaded rod (243) of the worm screw (242), the fixing nut (250) being mounted movably in translation on the threaded rod (243) of the worm screw (242), - an axial locking piece (266) for the worm screw (242) by relative to the hub (200), - a locking means (260) in rotation of the worm (242) relative to the hub (200), and - a means of rotating the worm (242).

2. Angular adjustment assembly (20) according to claim 1, characterized in that the fixing nut (250) of the adjustment device (240) is a cylinder with axis A4.

3. Annular adjustment assembly (20) according to claim 1, characterized in that the fixing nut (250) of the adjustment device (240) is a sphere.

4. Angular adjustment assembly (20) according to any one of the preceding claims, characterized in that the locking piece (266) is arranged to bear against the first face (202A) of the hub (200) and includes a housing (268) in which the head (244) of the worm screw (242) is free to translate along the face (202A), in the direction T2.

5. Angular adjustment assembly (20) according to any one of the preceding claims, characterized in that the locking means (260) comprises a nut (264) arranged at one end (246) of the threaded rod (243) of the worm gear (242), opposite the second face (202B) of the hub (200).

6. Angular adjustment assembly (20) according to any one of the preceding claims, characterized in that the recess (224) of the base (220) of the adjustable-orientation blade (210) is open in a direction perpendicular to the axes A3 and A4.

7. Angular adjustment system (18) of a ring (182) of adjustable-orientation blades (210) of a turbomachine or turbomachine test machine (10), characterized in that it comprises an angular adjustment assembly (20) according to any one of claims 1 to 6 for each of the adjustable-orientation blades (210).

8. Angular adjustment system (18) according to claim 7 characterized in that it further comprises a device for synchronizing the rotation of the threaded rods (243) of the worm screws (242) of the adjustment device (240) of the angular adjustment assemblies (20).

9. Aircraft turbomachine comprising at least one angular adjustment assembly (20) according to any one of claims 1 to 6.

10. Turbomachine test machine (10) comprising at least one angular adjustment assembly (20) according to any one of claims 1 to 6.

11. Method for angular adjustment of an adjustable-orientation blade (210) characterized in that it is carried out by means of an angular adjustment assembly (20) according to any one of claims 1 to 6 and comprising the following steps: - unlocking the worm screw (242) by means of the locking mechanism (260) of the adjustment device (240), - rotation of the threaded rod (243) of the worm screw (242) of the adjustment device (240) until it reaches a desired position of the adjustable-orientation blade (210) relative to the hub (200), and - locking of the worm screw (242) by means of the locking mechanism (260) of the adjustment device (240).

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