Bevel gear angular adjustment assembly for adjustable pitch vane and associated adjustment method

Abstract

Bevel gear angular adjustment assembly for variable pitch blade and associated adjustment method One aspect of the invention relates to an angular adjustment assembly (1) for an adjustable orientation blade (6) of a turbomachine or X-axis testing machine, comprising an adjustment device (19) capable of pivoting the blade about a Y axis perpendicular to and intersecting the X axis until the desired angular positioning is reached. The blade comprises at its base (8) a first bevel gear (15) of Y axis, the pivoting of which causes that of the blade. The adjustment device comprises a second bevel gear (18) of X' axis parallel to X, meshed with the first bevel gear and the rotation of which about the X' axis causes the pivoting of the first bevel gear 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 turbomachines and testing machines for the development of aircraft turbomachines.

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

[0003] Aircraft turbomachines often have adjustable-orientation blades, also called variable-pitch blades or pivoting blades. These blades can pivot about their axis, in order to adjust their angular position (their angle of attack) relative to the airflow passing through them and thus optimize the airflow in the turbomachine.

[0004] Stator stages of variable-pitch vanes are thus often found between the moving wheels of turbomachine compressors. These may also be flow straightening vanes located downstream of the fan, called outlet guide vanes or OGV vanes (Outlet guide vanes in English).

[0005] Such blades are carried by a stator casing and can be pivoted during engine operation, which makes it possible to optimize their action according to the engine speed and flight conditions. Since the performance of the turbomachine relies on the precision of the angular positioning of these blades relative to the casing, 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 which passes through an opening in the outer casing. Control rods are fixed laterally to the free ends of these control rods and are connected by their other end to a rotating crown located outside the casing. A servo system, electric, pneumatic or hydraulic, automatically controls the rotation of the crown according to the operating conditions, which causes the pivoting of the rods and thus the modification of the inclination of the variable-pitch 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. In addition, the adjustment during assembly of the orientation of the blade relative to the connecting rod must be particularly fine.

[0008] An objective of the invention is to propose an assembly for alternative angular adjustment of variable-pitch blades, usable in a turbomachine, which is mechanically simpler and which is at the same time rapid, precise, reliable and repeatable.

[0009] Adjustable orientation blades are also found in testing machines for the development of aircraft turbomachines. These testing 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 blades of the rotors and the fixed blades of the stators to obtain the best possible performance.

[0010] The testing machines therefore conventionally comprise blades with adjustable orientation in order to be able to simulate a precise angular positioning of these blades and / or test different positions depending on 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 displacement of the blade and thus position it with the desired pitch angle. This operation is long and meticulous and must be carried out blade by blade by an experienced operator.

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

[0013] A first aspect of the invention relates to an assembly for angular adjustment of an adjustable orientation blade of a turbomachine or of an X-axis turbomachine testing machine.

[0014] This angular adjustment assembly includes: • an adjustable orientation blade, comprising a base and a body extending radially from this base, the adjustable orientation blade being free to pivot about an axis Y perpendicular to and intersecting the axis X; 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 Y-axis bevel gear, free to pivot around the Y-axis and kinetically connected to the adjustable orientation blade, and the adjustment device comprises a second X'-axis bevel gear parallel to the X-axis, which is engaged with the first bevel gear. Thus, pivoting 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 movement of one being transmitted to the other without modification (they have no relative movement). They can be monobloc (made from a single piece) or fixed to each other.

[0017] This angular adjustment assembly can be used both in an aircraft turbomachine and in an aircraft turbomachine testing machine.

[0018] In a turbomachine, it can, for example, allow the angular position of the outlet guide vanes or the variable-pitch vanes of the compressors to be adjusted in order to adapt their angular positioning to the engine speed and the flight conditions and thus to optimize the operation of the turbomachine.

[0019] In a test machine, it can be used to adjust the angular position of any blade whose angular orientation has been provided to be adjustable in the test machine (this blade being able to be fixed once installed in a turbomachine). Different angular positions of this blade can thus be tested by means of the test machine and it is possible to define an aerodynamically optimal angular position (an optimal pitch angle) to be reproduced later in the turbomachine to improve performance.

[0020] The invention provides a bevel gear angular adjustment assembly which is mechanically simple. The adjustment, originating from the interaction of two bevel gears meshed with each other, is mechanical and particularly reliable. Furthermore, it has excellent repeatability which allows a return to a previous angular position of the blade with increased precision.

[0021] In addition, it advantageously allows the angular position of the blade to be adjusted easily and quickly, without having to dismantle any part to achieve this.

[0022] Furthermore, the precision of the adjustment can be easily adapted to the needs 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 slight rotation of the first bevel gear and therefore of the blade concerned. A very fine adjustment of the angular position of this blade is then possible without difficulty.

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

[0024] The base of the blade is thus shaped into a bevel gear. This simplifies assembly. In addition, the precision of the adjustment of the angular positioning of the blade is further improved, because with two single-piece parts, the movement is integral and instantly transmitted between the first bevel gear and the blade. This avoids any potential offset between the first bevel gear and the blade that could be induced by play between two assembled parts.

[0025] Advantageously, the angular adjustment assembly may further comprise 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 makes it possible to house both the base of the blade and the second bevel gear, while allowing them to cooperate with each other to enable the operation of the gear, via the communication of their respective housing. Thus, the overall size of the angular adjustment assembly is restricted 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 in one piece with it, and which is coaxial with said second bevel gear. It therefore extends along the axis X'.

[0028] This adjustment rod, which is kinematically linked to the second bevel gear, allows the second bevel gear to be pivoted in a simple and practical manner.

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

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

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

[0032] Other alternative locking systems may be envisaged, for example using a servomotor system, motor, controlled or non-controlled magnet, mechanical lock, in particular of the mechanical grasshopper type, or the like. However, the tight support by locking screw is advantageously the simplest and most economical solution.

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

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

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

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

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

[0038] This hollow imprint allows a portion of a tool of suitable complementary shape to be engaged therein, in order to connect this tool to the adjustment rod. The adjustment rod can then be easily rotated by means of this tool, which causes the rotation of the second bevel gear.

[0039] Alternatively, protruding reliefs may be provided at the free end of the adjustment rod in order to facilitate its gripping by means of a tool.

[0040] Advantageously, the angular adjustment assembly may further comprise a device for motorizing the rotation of the second bevel gear.

[0041] This motorization device makes it possible to automate the angular adjustment, which is particularly advantageous in the case of an application for an aircraft turbomachine. For this, a servomotor will be used, for example.

[0042] A second aspect of the invention relates to a system for angular adjustment of a crown of blades with adjustable orientation of a turbomachine or turbomachine testing machine, which comprises an angular adjustment assembly as described previously for each of the blades with adjustable orientation.

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

[0044] The synchronization device makes it possible to connect all the gears of the different angular adjustment assemblies 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 changed synchronously, i.e. simultaneously and in the same way.

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

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

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

[0048] A fifth aspect of the invention relates to a method for angular adjustment of a variable-pitch blade, carried out by means of an angular adjustment assembly as described previously and in which: • the second bevel gear is rotated until the adjustable orientation vane has reached the desired angular position.

[0049] Advantageously, when this method is carried out by means of 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 no longer rests against the adjustment rod, • the second bevel gear is rotated using the adjustment rod until the adjustable vane has reached the desired angular position, • tighten the locking screw until it rests against the adjustment rod.

[0050] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0051] The figures are presented for information purposes only and in no way limit the invention.

[0052] [Fig.l] is a sectional view of a portion of a testing machine according to an example of the invention.

[0053] [Fig.2] is a schematic side view of an exemplary 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 in different figures has a single reference.

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

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

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

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

[0060] Furthermore, the expressions “variable pitch vane”, “adjustable orientation vane” or “pivoting vane” 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 testing machine 2.

[0062] An example of a test machine 2 has been partially shown in [Fig.l]. 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 fan 3 formed from a ring of moving 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 in [Fig.l]).

[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 crown 5 can advantageously be associated with a synchronization device. Together they form an angular adjustment system 7 for the crown 5 of adjustable orientation blades 6.

[0065] An example of adjustment set 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 substantially radial general direction.

[0067] In order to be able to adjust its orientation, the blade 6 is mounted to rotate freely around a radial Y axis, perpendicular and intersecting the X axis. It is thus capable of pivoting around the Y axis, which modifies the angular position of the blade 11 which can consequently adopt any angular position which 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 in the upper part, 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 closing 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 comprises 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 connected to the blade 6 and therefore also free to rotate around the axis Y.

[0071] In the example shown, this bevel gear 15 is directly shaped 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 bevel gear 15 comprises on its periphery a multitude of teeth 16 which mesh with the teeth 17 of a second bevel gear 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 makes it possible to pivot the adjustable orientation blade 6 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 pivoting around the Y axis of the blade 6 which is kinematically linked to it.

[0074] The adjustment device 19 further comprises an adjustment rod 20, one end 21 of which is fixed to or made in 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 adjustment rod 20 extends along the axis X' while being coaxial with the pinion 18 and preferably has a change in diameter creating a shoulder 23.

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

[0077] This housing 24 communicates with the housing 12 in which the base 8 of the blade 6 is located. The bevel gear 18 can thus protrude from the housing 24 and end up in the housing 12 to mesh with the bevel gear 15.

[0078] A hollow shape or imprint 29 is provided at the free end 30 of the adjustment rod 20. It has the complementary shape of the end 31 of a tool 32 which can be engaged therein to drive it in rotation along the axis X'. It can thus, for example, have a hollow hexagonal, cruciform, square, slotted or star-shaped shape, complementary to that of a suitable wrench or screwdriver. Depending on the applications, this tool can be manual or automated (by servomotor or other mechanical locking).

[0079] The angular adjustment assembly 1 shown comprises 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 comes to bear against the adjustment rod 20. It thus prevents the pivoting of the adjustment rod 20 around the axis X', which blocks 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, it is sufficient to loosen the locking screw 33 so that it is no longer in contact with the adjustment rod 20, which frees it from pivoting.

[0081] The different steps of an adjustment method 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 make it rise in 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 released.

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

[0084] The teeth 17 of the bevel gear 18 being engaged with the teeth 16 of the bevel gear 15, this rotation of the gear 18 causes that of the bevel gear 15 around its axis Y and consequently that of the blade 6 which is kinetically linked to it. The rotation of the blade 6 along the axis Y has been symbolized by the arrow 38.

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

[0086] The last step, shown in [Fig.5], consists of locking the adjustment assembly 1 again to lock the blade 6 in the desired angular position which was obtained in the previous step. To do this, it is sufficient to screw the locking screw 33 to lower it into the bore 34 as shown by the arrow 39. The locking screw 33 ends up coming into abutment against the adjustment rod 20 and its tightening blocks the rotation of the adjustment rod 20 and thereby the rotation of the bevel gear 18. The adjustment assembly 1 is then locked.

Claims

Claims

1. Angular adjustment assembly (1) for an adjustable orientation blade (6) of a turbomachine or of a testing machine (2) of an X-axis turbomachine, said angular adjustment assembly comprising: - an adjustable orientation blade (6), comprising a base (8) and a body (10) extending radially from this base, the adjustable orientation blade (6) being free to pivot about a Y axis perpendicular to and intersecting the X axis; and - a device (19) for adjusting the pivoting of the adjustable orientation blade (6) around the Y axis, - characterized in that the adjustable orientation blade (6) comprises at its base (8) a first bevel gear (15) with axis Y, free to pivot around the Y axis and kinetically connected to the adjustable orientation blade (6), and - in that the adjustment device (19) comprises a second bevel gear (18) with axis X' parallel to the X axis which is engaged with the first bevel gear (15).

2. Angular adjustment assembly (1) according to claim 1, characterized in that the adjustment device (19) further comprises an adjustment rod (20), one end (21) of which is fixed on or integrally with the second bevel gear (18), and which is coaxial with said second bevel gear (18).

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

4. Angular adjustment assembly (1) according to one of the preceding claims, characterized in that it further comprises a device for motorizing the rotation of the second bevel gear (18).

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

6. Angular adjustment system (7) according to claim 5 characterized in

7.

8.

9. which further comprises a device for synchronizing the rotation of the second bevel gears (18) of the angular adjustment assemblies (1). Aircraft turbomachine comprising at least one angular adjustment assembly (1) according to one of claims 1 to 4. Turbomachine testing machine (2) comprising at least one angular adjustment assembly (1) according to one of claims 1 to 4. 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 one of claims 1 to 4 and in which: the second bevel gear (18) is rotated until the adjustable orientation vane (6) has reached the desired angular position.

10. Angular adjustment method according to claim 9 characterized in that it is carried out by means of an angular adjustment assembly (1) according to claim 3 or claim 4 in that it depends on claim 3 and in that: - loosen the locking screw (33) until it no longer rests against the adjustment rod (20), - the second bevel gear (18) is rotated using the adjusting rod (20) until the adjustable vane (6) has reached the desired angular position, - tighten the locking screw (33) until it rests against the adjustment rod (20).

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