Bevel gear angular adjustment assembly for adjustable-orientation blade and associated adjustment method

Abstract

Angular adjustment assembly with bevel gear for variable-pitch blade and associated adjustment method. One aspect of the invention relates to an angular adjustment assembly (1) for an adjustable-slope blade (6) of a turbomachine or X-axis testing machine, comprising an adjustment device (19) capable of rotating the blade about a Y-axis perpendicular to and intersecting the X-axis until the desired angular positioning is achieved. The blade includes at its base (8) a first bevel gear (15) about the Y-axis, the rotation of which causes the blade to rotate. The adjustment device includes a second bevel gear (18) about the X'-axis parallel to X, meshing with the first bevel gear, and whose rotation about the X'-axis causes the first bevel gear to rotate about the Y-axis. Figure to be published with the abstract: Figure 2

Description

Title of the invention: Bevel gear angular adjustment assembly for 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-orientation 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] Aircraft turbomachinery often incorporates adjustable-pitch blades, also known as variable-pitch or pivoting blades. These blades can pivot around their axis to adjust their angular position (their angle of attack) relative to the airflow passing through them, thereby optimizing airflow within the turbomachine.

[0004] Variable pitch stator stages are thus often found between the moving wheels of turbomachinery compressors. These can also be flow straightening vanes located 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 current technique, these variable-pitch 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 variable-pitch blades.

[0007] For this system to be functional, the coupling between the control rod and the connecting rod of a blade must be precise and able 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 propose an alternative angular adjustment system for variable pitch blades, usable in a turbomachine, which is mechanically simpler and is both fast, precise, reliable and repeatable.

[0009] Adjustable-orientation blades are also found in test machines for the development of aircraft turbomachinery. These test machines make it possible to test the aerodynamic and acoustic behavior of the various elements of the turbomachine and, in particular, to determine the optimal angular positioning of the moving rotor blades and the fixed 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 variable-pitch blades is done manually using complex tools to measure the blade displacement and thus position it with the desired pitch angle. 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] A first aspect of the invention relates to an angular adjustment assembly for an adjustable-orientation blade of a turbomachine or X-axis turbomachine test machine.

[0014] This angular adjustment assembly comprises: • a blade with adjustable orientation, comprising a base and a body extending radially from this base, the adjustable-orientation blade being free to pivot about a Y-axis perpendicular to and intersecting the X-axis; and • a device for adjusting the pivoting of the blade with adjustable orientation around the Y axis.

[0015] According to the invention, the adjustable-orientation blade comprises at its base a first bevel gear with axis Y, free to pivot about the Y axis and kinematically linked with the adjustable-orientation blade, and the adjustment device includes a second bevel gear with axis X' parallel to the X-axis, which meshes with the first bevel gear. Thus, the pivoting of the second bevel gear around the X' axis causes the first bevel gear to pivot around the Y-axis.

[0016] The expression "kinematically linked" means that the first bevel gear and the blade move together and in the same way, the motion of one being transmitted to the other without modification (they have no relative motion). They can be monoblocs (made from a single piece) or fixed to each other.

[0017] This angular adjustment assembly is usable both in an aircraft turbomachine and in an aircraft turbomachine test machine.

[0018] In a turbomachine, it can, for example, allow the angular position of the outlet guide vanes or the variable-pitch compressor vanes 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.

[0019] In a test machine, it can allow the angular position of any blade whose angular orientation has been designed to be adjustable in the test machine to be set (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 and subsequently reproduced in the turbomachine to improve performance.

[0020] The invention provides a mechanically simple angular adjustment system using bevel gears. The adjustment, resulting from the interaction of two meshing bevel gears, is mechanical and particularly reliable. Furthermore, it exhibits excellent repeatability, allowing the blade to return to a previous angular position with increased precision.

[0021] In addition, it advantageously allows the angular position of the blade to be adjusted in an easy and quick manner, without having to disassemble any part to achieve this.

[0022] Furthermore, the precision of the adjustment can be easily adapted to the requirements by choosing the relative size of the bevel gears. Indeed, the precision can be very simply increased by modifying the relative size of these gears to obtain a higher reduction ratio. Thus, a complete revolution of the second bevel gear may cause only a small rotation of the first bevel gear and therefore of the blade in question. Very fine adjustment of the angular position of this blade is then easily possible.

[0023] Advantageously, the first bevel gear can be one piece with the adjustable orientation blade base.

[0024] The base of the blade is thus shaped into a bevel gear. This simplifies assembly. Furthermore, the precision of the angular positioning adjustment of the blade is further improved, because with two one-piece components, the movement is transmitted completely and instantaneously between the first bevel gear and the blade. This eliminates any potential misalignment between the first bevel gear and the blade that could be caused by play between two assembled parts.

[0025] Advantageously, the angular adjustment assembly may further include a hub which has communicating housings in which the base of the adjustable-orientation blade and the second bevel gear are housed.

[0026] The hub accommodates both the blade base and the second bevel gear, while allowing them to cooperate with each other to enable the gear to function, via the communication between their respective housings. Thus, the overall size of the angular adjustment assembly is reduced and the gear is protected from the external environment.

[0027] Advantageously, the adjustment device may further comprise an adjustment rod, one end of which is fixed to the second bevel gear or is integral with it, and which is coaxial with said second bevel gear. It therefore extends along the X' axis.

[0028] This adjusting rod, which is kinematically linked with the second bevel gear, allows the second bevel gear to be rotated in a simple and practical way.

[0029] Advantageously, such an angular adjustment assembly may further include a locking screw which, when tightened, bears against the adjustment rod.

[0030] This locking screw prevents the adjusting rod from rotating when it is pressed firmly against it, and consequently prevents the rotation of the second bevel gear to which it is kinematically linked. The pivoting of the first bevel gear is then also impossible, and the blade is locked in its angular position. The entire angular adjustment assembly is thus completely locked.

[0031] The locking or unlocking of the angular adjustment assembly is thus very simply done by screwing or unscrewing this locking screw.

[0032] Other alternative locking systems can be considered, for example using a servomotor, motor, driven or undriven magnet, mechanical lock, particularly of the mechanical toggle type, or similar. However, the clamping support by locking screw is advantageously the simplest and most economical solution.

[0033] Optionally, this locking at the level of the adjusting rod can be supplemented by an additional locking at the level of the blade.

[0034] Advantageously, the angular adjustment assembly may further include a stop ring mounted on the adjustment rod.

[0035] This stop ring prevents the longitudinal translation of the adjusting rod along the direction of its X' axis.

[0036] Other axial retention methods can be used alternatively. For example, retention by shoulder, by stop screw or by any other similar means can be considered.

[0037] Advantageously, a hollow recess can be provided at the free end of the adjusting rod.

[0038] This hollow recess allows a complementary shaped portion of a tool to be engaged in order to connect this tool to the adjusting rod. The adjusting rod can then be easily rotated by means of this tool, which causes the second bevel gear to rotate.

[0039] Alternatively, protruding reliefs may be provided at the free end of the adjusting rod to facilitate gripping it with a tool.

[0040] Advantageously, the angular adjustment assembly may further include a device for motorizing the rotation of the second conical pinion.

[0041] This motorization device allows for automated angular adjustment, which is particularly advantageous in the case of an application for an aircraft turbomachine. For this purpose, a servomotor will be used, for example.

[0042] 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 as described above for each of the adjustable-orientation blades.

[0043] Advantageously, such an adjustment system may further include a device for synchronizing the rotation of the second conical gears of the angular adjustment assemblies.

[0044] The synchronizing device allows all the gears of the different angular adjustment assemblies to be linked together so that they are actuated simultaneously and in the same way. The angular position of all the blades of the blade ring can thus be modified in a synchronized manner, that is to say simultaneously and in the same way.

[0045] This synchronization device may, for example, comprise a set of universal joints or a common toothed ring engaging with conjugate teeth made at the free end of the adjusting rods.

[0046] A third aspect of the invention relates to an aircraft turbomachine comprising at least one angular adjustment assembly as described above.

[0047] A fourth aspect of the invention relates to a turbomachine test machine comprising at least one angular adjustment assembly as described above.

[0048] 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 as described above and in which: • The second bevel gear is rotated until the adjustable-orientation blade has reached the desired angular positioning.

[0049] Advantageously, when this method is carried out using an angular adjustment assembly comprising an adjustment rod and a locking screw which, when tightened, bears against the adjustment rod, this method may comprise the following steps: • Loosen the locking screw until it is no longer in contact with the adjusting rod, • The second bevel gear is rotated using the adjusting rod until the adjustable-orientation blade has reached the desired angular positioning. • tighten the locking screw until it is pressed against the adjusting rod.

[0050] 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

[0051] The figures are presented for illustrative purposes only and are in no way limiting of the invention.

[0052] [Fig.1] is a cross-sectional view of a portion of a test machine according to an example of the invention.

[0053] [Fig.2] is a schematic side view of an example adjustment assembly angular according to the invention.

[0054] [Fig.3], [Fig.4] and [Fig.5] are partial side views schematically illustrating the successive steps of an example of an adjustment method according to the invention. DETAILED DESCRIPTION

[0055] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0056] In the present application, the terms "upstream" and "downstream" are defined with respect to the normal direction of gas flow (upstream to downstream) through a turbomachine or turbomachine test machine.

[0057] The longitudinal axis of the turbomachine or test machine corresponding to the axis of rotation of the rotor of that turbomachine or test machine is also called the "turbomachine axis" or "test machine axis." This axis is designated X in the figures. The axial direction corresponds to the direction of this axis X and a A radial direction is a direction perpendicular to the X-axis and intersecting it. For example, the X' axis has an axial direction and the Y-axis has a radial direction.

[0058] Unless otherwise specified, the adjectives "interior", "internal", "exterior", "external" are used in this application with reference to a radial direction, so that the inner part of an element is, along a radial direction, closer to the X axis than the outer part of the same element.

[0059] Furthermore, the terms "top", "bottom", "upper", "lower" are defined with respect to the orientation of the parts as shown in the figures. It is clear that this orientation will not necessarily be maintained during use.

[0060] Furthermore, the expressions "variable pitch blade", "adjustable orientation blade" or "pivoting blade" are synonymous.

[0061] The figures show an example of an angular adjustment assembly 1 according to the invention. This angular adjustment assembly 1 can be installed in a turbomachine or in a turbomachine test machine 2.

[0062] An example of a test machine 2 has been partially shown in [Fig. 1]. Such a test machine 2 makes it possible to simulate an aircraft turbomachine and to test its components under different aerodynamic conditions in order to study their performance.

[0063] The test machine 2 thus comprises, for example, a blower 3 formed of a ring of movable blades 4, followed downstream by a rectifier stator ring 5 comprising adjustable orientation blades 6 of the OGV type (one of which has been framed for greater visibility on [Fig.1]).

[0064] An angular adjustment assembly 1 is advantageously installed for each of these adjustable-orientation blades 6. All the angular adjustment assemblies 1 of the ring 5 can advantageously be combined with a synchronizing device. Together they form an angular adjustment system 7 for the ring 5 of adjustable-orientation blades 6.

[0065] An example of a setting assembly 1 has been more specifically represented in [Fig.2],

[0066] The adjustable-orientation blade 6 comprises a base 8, mounted in a hub 9, and a body 10 which rises out of the hub 9 from this base 8. This body 10 forms a curved blade 11 which extends in a generally radial direction.

[0067] In order to be able to adjust its orientation, the blade 6 is mounted freely to rotate around a radial Y axis, perpendicular and intersecting the X axis. It is thus able to pivot around the Y axis, which modifies the angular position of the blade 11 which can therefore adopt any angular position that can be obtained by a rotation from 0 to 360°.

[0068] The base 8 of the blade 6 is engaged in a housing 12 of the hub 9, which is generally cylindrical and open upwards. The diameter of this housing 12 widens at the top, thus forming a shoulder 13.

[0069] The upper part 14 of the base 8 rests on the shoulder 13 of the housing 12 and thus ensures the longitudinal retention of the blade 6. This upper part 14 also serves as a cover for the housing 12 by sealing its upper opening. It thus protects the parts of the device located in the housing 12 from the environment prevailing in the turbomachine or the test machine 2.

[0070] The blade 6 also includes a first bevel gear 15 with axis Y, which is located in the lower part of the base 8 and extends downwards. This bevel gear 15 is kinematically linked with the blade 6 and is therefore also free to rotate about the Y axis.

[0071] In the example shown, this bevel gear 15 is directly formed in the lower part of the base 8 of the blade 6 (i.e., made in one piece with it). But, it could also be attached and fixed to it.

[0072] This conical pinion 15 has on its periphery a multitude of teeth 16 which mesh with the teeth 17 of a second conical pinion 18, oriented along an axis X' perpendicular to the axis Y (and parallel to the axis X), to form a bevel gear.

[0073] This second bevel gear 18 belongs to an adjustment device 19 which allows the adjustable-orientation blade 6 to be rotated around the Y-axis to adjust its angular position. Indeed, the rotation of the bevel gear 18 around its X' axis causes the bevel gear 15 to pivot around the Y-axis and consequently the blade 6, to which it is kinematically linked, to pivot around the Y-axis.

[0074] The adjustment device 19 further includes an adjustment rod 20, one end of which 21 is fixed on or made of one piece with the rear face 22 of the bevel gear 18 (i.e. the face of the gear 18 located at the base of the cone and not having teeth 17).

[0075] The adjusting rod 20 extends along the X' axis while being coaxial with the pinion 18 and preferably has a change in diameter creating a shoulder 23.

[0076] The adjusting rod 20 is disposed in a housing 24 of the hub 9. It is retained axially there, on the one hand by its shoulder 23 which comes against a complementary shoulder 25 of the housing 24, and on the other hand by a stop ring 26 (also called stop ring or circlip) placed in a circular groove 27 of the adjusting rod 20 which comes against the wall 28 of the hub 9.

[0077] This housing 24 communicates with the housing 12 in which is located the base 8 of the blade 6. The conical pinion 18 can thus protrude out of the housing 24 and be found in the housing 12 to mesh with the conical pinion 15.

[0078] A hollow shape or recess 29 is provided at the free end 30 of the adjusting rod 20. It has the complementary shape of the end 31 of a tool 32 which can be engaged in it to rotate it about the X' axis. It can thus, 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 can be manual or automated (by servomotor or other mechanical locking mechanism).

[0079] The angular adjustment assembly 1 shown includes a locking screw 33, which is mounted in a tapped bore 34 of the hub 9 opening into the housing 24 of the adjustment rod 20.

[0080] When the locking screw 33 is tightened, it protrudes into the housing 24 and bears against the adjusting rod 20. This prevents the adjusting rod 20 from pivoting about the X' axis, thus blocking the rotation of the bevel gear 18 and consequently also the rotation of the bevel gear 15. The blade 6 is then locked in position and the angular adjustment assembly 1 is locked. To unlock it, simply loosen the locking screw 33 so that it is no longer in contact with the adjusting rod 20, which releases it from pivoting.

[0081] The different stages of an adjustment process carried out using the adjustment assembly 1 described above have been schematically represented in figures 3 to 5.

[0082] The first step, shown in [Fig.3], consists of unlocking the adjustment assembly 1 by unscrewing the locking screw 33 to move it up into the bore 34. The translational movement of the screw 33 has been symbolized by the arrow 35. By this movement, the locking screw 33 is no longer in contact with the adjustment rod 20, which is then released.

[0083] The second step is shown in [Fig. 4] and consists of adjusting the angular positioning of the blade 6. For this purpose, the end 31 of a tool 32 is engaged in the recess 29 at the free end 30 of the adjusting rod 20, which is now free to rotate. By rotating this tool 32 in the direction of arrow 36, the adjusting rod 20 and the bevel gear 18 are rotated around its axis X', which is symbolized by arrow 37.

[0084] Since the teeth 17 of the bevel gear 18 mesh with the teeth 16 of the bevel gear 15, this rotation of the gear 18 causes the bevel gear 15 to rotate about its Y-axis, and consequently, the blade 6 to which it is kinematically linked. The rotation of the blade 6 about the Y-axis is symbolized by arrow 38.

[0085] When the blade 6 has reached the desired angular position, the tool 32 is stopped being operated to stop the rotation of the bevel gear 18.

[0086] The final step, shown in [Fig. 5], consists of re-locking the adjustment assembly 1 to secure the blade 6 in the desired angular position obtained in the previous step. This is done by tightening the locking screw 33 down into the bore 34 as shown by arrow 39. The locking screw 33 eventually comes to rest against the adjusting rod 20, and tightening it prevents the rotation of the adjusting rod 20 and thus the rotation of the bevel gear 18. The adjustment assembly 1 is then locked.

Claims

Demands

1. Angular adjustment assembly (1) of an adjustable-slope blade (6) of a turbomachine or X-axis turbomachine test machine (2), said angular adjustment assembly comprising: - an adjustable-slope blade (6), having a base (8) and a body (10) extending radially from this base, the adjustable-slope blade (6) being free to pivot about a Y-axis perpendicular and intersecting the X-axis;and - an adjustment device (19) for the pivoting of the adjustable-orientation blade (6) around the Y axis, - the adjustable-orientation blade (6) having at its base (8) a first bevel gear (15) of axis Y, free to pivot about the Y axis and kinematically linked with the adjustable-orientation blade (6), - characterized in that the adjustment device (19) comprises a second bevel gear (18) of axis X' parallel to the X axis which is meshed with the first bevel gear (15), and - an adjustment rod (20), one end (21) of which is fixed on or part of the second bevel gear (18), and which is coaxial with said second bevel gear (18).

2. Angular adjustment assembly (1) according to claim 1, characterized in that it further comprises a locking screw (33) which, when tightened, is in contact with the adjustment rod (20).

3. Angular adjustment assembly (1) according to any one of the preceding claims, characterized in that it further comprises a motorization device for the rotation of the second conical pinion (18).

4. Angular adjustment system (7) of a ring (5) of adjustable-orientation blades (6) of a turbomachine or turbomachine test machine (2), characterized in that it comprises an angular adjustment assembly (1) according to any one of claims 1 to 3 for each of the adjustable-orientation blades (6).

5. Angular adjustment system (7) according to claim 4 characterized in that it further comprises a synchronization device the rotation of the second conical gears (18) of the angular adjustment assemblies (1).

6. Aircraft turbomachine comprising at least one angular adjustment assembly (1) according to any one of claims 1 to 3.

7. Turbomachine test machine (2) comprising at least one angular adjustment assembly (1) according to any one of claims 1 to a

8. 3. Method for angular adjustment of a variable pitch blade (6) characterized in that it is carried out by means of an angular adjustment assembly (1) according to any one of claims 1 to 3 and in which: - the second bevel gear (18) is rotated by means of the adjustment rod (20) until the adjustable orientation blade (6) has reached the desired angular positioning.

9. Angular adjustment method according to claim 8 characterized in that it is carried out by means of an angular adjustment assembly (1) according to claim 2 or claim 3 in that it depends on claim 2 and in that: - the locking screw (33) is loosened until it is no longer in contact with the adjusting rod (20), - the second bevel gear (18) is rotated using the adjusting rod (20), until the adjustable-orientation blade (6) has reached the desired angular positioning, - the locking screw (33) is tightened until it is in contact with the adjusting rod (20).

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