Method for reinstalling blade shrouds of a rotor wheel in an aircraft turbine

Abstract

The invention relates to a method for refitting blade shrouds (14a) of a rotor wheel in an aircraft turbine, the rotor wheel having a disk supporting blades (10; 10a), each blade having an airfoil (26) extending between a root and a shroud, the shroud of each blade having a lateral edge having a shape complementary to the lateral edge of the shroud of an adjacent blade, the lateral edges of the shrouds being interlocked in such a manner that the anti-wear coatings of these edges contact each other in a desired interlocking engagement position, and at least one of the lateral edges of at least one of the shrouds (14a) being disengageable from the lateral edge of the adjacent shroud and being in an undesired disengaged position. According to the invention, the method comprises the steps of inserting a reengaging device into the turbine when such an undesired disengaged position is detected, and moving the at least one shroud (14a) from the undesired position to the desired interlocking engagement position.

Description

Technical Field

[0001] The invention relates to a method for refitting blade shrouds of a rotor wheel in an aircraft turbomachine, and to a reengaging device for carrying out this method. Background Art

[0002] The prior art is described in document FR-A1-2 950 104.

[0003] Typically, an axial turbine of a turbomachine comprises a series of axial stages arranged one after another (along the axis of gas flow). Each stage comprises a bladed movable wheel forming a rotor and a bladed turbine stator forming a stator. The movable wheel and the corresponding turbine stator rotate relative to each other.

[0004] In this application, upstream and downstream are defined relative to the normal flow direction of air flow through the turbine (from upstream to downstream). The axis of rotation of the main rotor of the turbine is called the "axis of the turbine". The axial direction is the direction of the turbine axis, and the radial direction is the direction perpendicular to the turbine axis and intersecting this axis. Similarly, an axial plane is a plane that includes the axis of the turbine, and a radial plane is a plane that is perpendicular to this axis. The adjectives "inner" and "outer" are used with respect to the radial direction, so that the inner part of an element is closer to the axis of the turbine than the outer part of the same element in the radial direction. The stacking axis of the blade is an axis perpendicular to the axis of the turbine, and the stacking axis of the blade passes through the center of gravity of the innermost section of the blade of the blade (i.e., the section closest to the axis of the turbine). Typically, a turbine blade comprises blades that extend along the stacking axis of the blade between the proximal end and the distal end (i.e., the inner end and the outer end) of the blade.

[0005] The movable wheel typically comprises an annular disk centered about the wheel's axis of rotation, to which a plurality of blades are attached.

[0006] exist Figure 1 An example of such a blade is shown in FIG. A blade of this type is described in patent document FR-A1-3 079 847. This blade 10 comprises blades 16 extending along the stacking axis X of the blade between a proximal end 10A and a distal end 10B of the blade 10. At the proximal end 10A of the blade, the blade comprises a platform 19 and a root 12, by means of which the blade is attached to a disk (not shown). At the distal end 10B of the blade, the blade 10 has a shroud 14.

[0007] The shroud 14 includes a platform 20 that externally delimits a flow duct for the gas circulating between the blades 16 and has opposite transverse edges 21, 22. The platform 20 includes an upstream portion 24, referred to as an "upstream spoiler," and a downstream portion 28, referred to as a "downstream spoiler." The shroud 14 also includes an upstream sealing lip 31 and a downstream sealing lip 32 that extend radially outward from the outer surface of the platform 20. Each of the platform transverse edges 21, 22 has a generally "U"-shaped profile between the upstream lip 31 and the downstream lip 32. In the case of other blades, this profile may be, for example, in the form of a "Z" or a "V."

[0008] In order to dampen the vibrations to which the blades 10 are subjected during operation and to impart rigidity to the assembly, the blades 10 are mounted on a blade disk and are subjected to torsional stress about a torsional axis positioned relative to the stacking axis X. The geometry of the shroud 14 places each blade 10 under torsional stress by bearing against the adjacent blades 10 at the lateral edges 21 and 22. These lateral edges 21, 22 thus define the contact surfaces between the blades and are locations where significant friction occurs during turbine operation.

[0009] The purpose of the lateral edges 21 and 22 is to suppress the first vibration bending mode to prevent the blade from dynamically fracturing due to resonance. The lateral edges maintain contact due to the torsional stresses of the blade. However, during operation, such a moving blade may experience interference from other components, preventing it from returning to its original assembly position. This can lead to a loss of contact between the lateral edges.

[0010] This loss of contact and the resulting gap between the shrouds can lead to the blades becoming disengaged, meaning that the concave and convex surfaces that should be in contact no longer do so, and the blade shrouds shift axially. This disengagement requires the removal and disassembly of the engine to replace the shrouds. Without this removal and disassembly, there is a loss of damping and even the risk of power failure, which in the worst case could result in an in-flight engine stop or partial or complete in-flight turbine damage. In addition to the risk of failure, another consequence is that the component cannot be repaired during or even before a maintenance visit and must be scrapped, which has a negative impact on costs.

[0011] Therefore, there is a need for a method of re-housing the blade shrouds of a rotor wheel in an aircraft turbomachine without requiring removal or disassembly of the engine or turbine from the turbomachine. Summary of the Invention

[0012] Thus, the present invention provides a method for reinstalling bucket shrouds of a rotor wheel in an aircraft turbine, the rotor wheel comprising a disk supporting buckets, each of the buckets having blades extending between a root and a shroud, the shroud of each bucket comprising a lateral edge having a shape complementary to the lateral edge of the shroud of an adjacent bucket, the lateral edges of the shrouds interlocking in an engaging manner such that the anti-wear coatings of the edges contact each other in a desired interlocking engagement position, and at least one of the lateral edges of at least one of the shrouds being disengageable from the lateral edge of the adjacent shroud and in an undesirable disengaged position.

[0013] According to the invention, the method comprises the steps of inserting a reengagement device into the turbine when such an undesired disengaged position is detected, and moving at least one shroud from the undesired position to a desired interlocked engaged position by bearing at least one shroud on the or each blade from which the shroud has disengaged or exerting a force on the or each blade from which the shroud has disengaged.

[0014] Thanks to the insertion of such a reengagement device in the turbomachine and thanks to the step of moving the shroud from an undesirable position to the desired interlocking engagement position, the method according to the invention makes it possible to reinstall one or more disengaged mobile blades directly under the wing, without having to dismantle the engine or turbine of the turbomachine. In this way, it is possible to avoid premature removal or dynamic breakage of components and of the engine or turbine. Thus, the process according to the invention maximizes and optimizes the use of the engine while ensuring healthier operation of the mobile blades. This process also makes it possible to reduce costs (due to maximizing the use of components and reducing the expected removal of the turbine, thus reducing the number of components to be replaced) and to reduce the number of repairs to be carried out during maintenance operations.

[0015] The method according to the invention may include one or more of the following features, taken independently of one another or in combination with one another:

[0016] - the reengagement device includes an endoscope;

[0017] - The reengagement device is inserted through the endoscope port of the turbine or through the aft or downstream of the turbine;

[0018] - the reengaging device comprises an endoscope including an illumination device and a viewing device, and a clamp or hook configured to cooperate with a blade or shroud of one of the buckets to perform the moving step;

[0019] - the clamps or hooks can be telescoped and / or moved relative to each other and / or relative to the endoscope;

[0020] The endoscope comprises clamps, each of which is configured to grip the leading edge and / or the trailing edge of a blade, or even the leading edge and / or the trailing edge of an adjacent blade, during the moving step;

[0021] - the endoscope comprises a first clamp configured to clamp a leading edge of a blade and a second clamp oriented in a direction different from that of the first clamp and configured to clamp a trailing edge of an adjacent blade;

[0022] the endoscope comprises hooks each configured to cooperate with a spoiler and / or a leading edge or a trailing edge of a blade of the shroud, or even with a leading edge or a trailing edge of an adjacent blade, during a movement step;

[0023] - the endoscope comprises a first hook portion which is slidably mounted relative to a second fixed hook portion of the endoscope;

[0024] - the endoscope comprises a member, for example in the form of a roller, which is rotatable about an axis, the method comprising engaging the member between two adjacent blades and rotating the member about said axis during the moving step so that the member bears on the two blades and biases the two blades in substantially opposite directions; and

[0025] The endoscope includes an inflatable member, the method including engaging the member between two adjacent blades and inflating the member during the moving step such that the member bears against the two blades and biases the two blades in generally opposite directions.

[0026] The present invention also relates to a reengaging device for performing the method as described above, wherein the reengaging device comprises an endoscope comprising an illumination device and an observation device and at least one element selected from the following elements:

[0027] - a clamp and / or a hook configured to cooperate with a blade or a shroud of one of the buckets during the moving step, and

[0028] - A movable or inflatable member configured to engage between two adjacent blades and bias the two adjacent blades in generally opposite directions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention will be better understood and other details, features and advantages of the invention will become clearer through the following description made by way of non-limiting example and with reference to the accompanying drawings, in which:

[0030] [ Figure 1 ] Figure 1 is a schematic perspective view of the blades of the movable wheel of the turbine,

[0031] [ Figure 2 ] Figure 2 is an enlarged schematic perspective view of a shroud of a blade of a movable turbine wheel,

[0032] [ Figure 3 ] Figure 3 is a schematic perspective view of a blade of a turbine blade,

[0033] [ Figure 4 ] Figure 4 is a schematic perspective view of the distal end of a reengagement device according to a first embodiment of the present invention, the distal end being in a deployed position,

[0034] [ Figure 5 ] Figure 5 yes Figure 4 a schematic perspective view of the distal end of the reengagement device of FIG. 1 , the distal end being in a stowed position,

[0035] [ Figure 6 ] Figure 6 is a side view of a distal end portion of a reengagement device according to a second embodiment of the present invention, the distal end portion comprising two hook portions according to the first embodiment,

[0036] [ Figure 7 ] Figure 7 yes Figure 6 a cross-sectional view of the distal end of the reengagement device taken along section plane AA,

[0037] [ Figure 8 ] Figure 8 yes Figure 6 Schematic diagram of the distal end of the reengagement device,

[0038] [ Figure 9 ] Figure 9 is similar to Figure 6 The distal end comprises two hook portions according to the second embodiment,

[0039] [ Figure 10 ] Figure 10 is similar to Figure 8 In the third embodiment, the distal end portion includes two hooks,

[0040] [ Figure 11 ] Figure 11 is a perspective view of the underside of a first device for transmitting mechanical force between two hooks of a reengaging device according to a second embodiment of the present invention, the first device comprising a cable,

[0041] [ Figure 12 ] Figure 12 yes Figure 11a vertical cross-sectional view of one of the two hooks of , taken at the level of the cable attachment,

[0042] [ Figure 13 ] Figure 13 is a vertical cross-sectional view of a second device for transmitting mechanical force between two hooks of a reengaging device according to a second embodiment of the present invention,

[0043] [ Figure 14 ] Figure 14 is a schematic perspective view of a distal end portion of a reengagement device according to a third embodiment of the invention, the distal end portion being in an inserted position between two rotor blades,

[0044] [ Figure 15 ] Figure 15 yes Figure 14 a schematic perspective view of a distal end of a reengaging device in a position to reengage a shroud of one of the blades,

[0045] [ Figure 16 ] Figure 16 is a perspective view of the distal end of a reengagement device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0046] The invention relates to a method and a reengaging device 40 for refitting the shrouds 14 of the blades 10 of a movable wheel of a turbomachine. Such a movable wheel (not visible in the drawings) forms the rotor of the axial turbine of the turbomachine and generally comprises an annular disk centered on the axis of rotation of the wheel to which the blades 10 are attached. Figure 1 Such a blade 10 is shown in FIG.

[0047] The bucket 10 includes blades 16 extending along the bucket's stacking axis X between its proximal end 10A and distal end 10B. At its proximal end 10A, the bucket includes a platform 19 and a root 12, via which the bucket is attached to a disk (not shown). At its distal end 10B, the bucket 10 has a shroud 14. When a plurality of buckets 10 are attached to a disk, the shrouds 14 of the buckets are arranged edge to edge to form a circular ring that defines a surface that rotates about the wheel's axis of rotation A. In particular, this ring serves to define the outer surface of the flow duct for the gas flow circulating between the blades 16 and to limit gas leakage at the distal end 10B of the bucket 10.

[0048] The shroud 14 includes a platform 20 that externally delimits a flow duct for the gas circulating between the blades 16 and has opposite transverse edges 21, 22. The platform 20 includes an upstream portion 24, referred to as an "upstream spoiler," and a downstream portion 28, referred to as a "downstream spoiler." The shroud 14 also includes an upstream sealing lip 31 and a downstream sealing lip 32 that extend radially outward from the outer surface of the platform 20. Each of the platform transverse edges 21, 22 has a generally "U"-shaped profile between the upstream lip 31 and the downstream lip 32. In the case of other blades, this profile may be, for example, in the form of a "Z" or a "V."

[0049] In order to dampen the vibrations to which the blades 10 are subjected during operation and to impart rigidity to the assembly, the blades 10 are mounted on a disk of blades and are subjected to torsional stress about a torsional axis situated relative to the stacking axis X. The geometry of the shroud 14 is such that each blade 10 is subjected to torsional stress by being supported on the adjacent blade 10 at the lateral edges 21 and 22. The lateral edges 21, 22 of each blade 10 comprise a shape complementary to the lateral edges 22, 21 of the shroud 14 of the adjacent blade 10, so that the lateral edges of each blade define inter-blade contact surfaces and said lateral edges are the sites where there is significant friction during operation of the turbine. In order to prevent wear, these edges are provided with a coating made of a friction-resistant and anti-wear material. This may be, for example, a coating under the brand name Materials for sale. Figure 2 This coating 36 can be seen in FIG.

[0050] Typically, the anti-wear coating 36 is deposited on the lateral edges 21, 22 by welding, for example by drop welding, which involves generating an electric arc to melt the material. This is typically a manual operation, wherein during deposition, The alloy is in the form of liquid droplets.

[0051] The alloy is a steel alloy with high chromium (Cr) and cobalt (Co) content. The alloy may also contain small amounts of tungsten (W) or molybdenum (Mo) and small amounts of carbon (C). The alloy is not forgeable and must be cast or welded into an object. The alloy forms part of or is inserted into the object.The lateral edges 21 , 22 of the shroud 14 interlock in an engaging manner such that the anti-wear coatings 36 on the edges 21 , 22 contact each other in the desired interlocking engagement position.

[0052] However, during operation, the buckets 10 may experience interference from other components, and at least one of the buckets 10 may not return to the original assembled position of the bucket. This may result in a loss of contact between the adjacent lateral edges 21, 22. This loss of contact and the resulting gap between the shrouds 14 may cause one of the buckets to become disengaged, i.e., the concave and convex surfaces that should be in contact no longer do so, and the shroud of the bucket is axially displaced. For the remainder of this description, it will be assumed that the shroud 14A of the bucket 10A (at Figure 14 and Figure 15 ) is disengaged from the normal interlocking engagement position of the shield.

[0053] Figure 3 The leading edge 26a and the trailing edge 26b of the blade 26 are shown.

[0054] Figure 3 The reference numerals CR10, CR50, and CR90 in the figures refer to the heights in the gas flow duct in which the blades 26 are intended to extend. CR50 refers to the mid-height of the duct, and thus is located on a circle centered on the duct's axis of rotation and midway between the duct's outer and inner circumferences. CR10 is located on a circle centered on the duct's axis of rotation and at 10% of the duct's height, measured from the duct's inner circumference. CR90 is located on a circle centered on the duct's axis of rotation and at 90% of the duct's height, measured from the duct's inner circumference.

[0055] The reengagement device 40 includes an endoscope 42 .

[0056] Figure 4 and Figure 5 A first embodiment of an endoscope 42 according to the present invention is shown.

[0057] The endoscope 42 has a generally elongated shape and is preferably flexible. It comprises a proximal end, which is positioned on the operator's side, and a distal end, which must be positioned as close as possible to the blade to be reengaged, of which only the distal end is shown in the figure. The distal end comprises a head 46.

[0058] The endoscope 42 is equipped with optical elements for illumination and visualization, such as a first optical fiber whose proximal end is connected to a camera and whose distal end 48 a leads to at least one lens, for example at the level of the head 46 , and a second optical fiber whose proximal end is connected to a light source and whose distal end 48 b leads to the head 46 .

[0059] The head 46 is located at one end of a body 50 of the endoscope 42. The body 50 is generally tubular in shape and serves, inter alia, to support positioning fixtures 52,54.

[0060] In the example shown, the endoscope 42 includes two positioning clamps 52, 54. The two positioning clamps 52, 54 are oriented in an inverted manner relative to the extension direction of the main body 50. The clamps 52, 54 have jaws 56 or fixed jaws. The clamps 52, 54 each have a generally V-shaped shape, wherein the angle between the jaws 56 is determined so that the clamps can engage on the leading edge 26a or the trailing edge 26b of the blade. More specifically, the first clamp 52 is configured to clamp the leading edge 26a of the blade, while the second clamp 54 is configured to clamp the trailing edge 26b of the adjacent blade, and vice versa.

[0061] The clamps 52, 54 have free ends, advantageously each equipped with a contact element, preferably made of a material that does not damage the blade during contact, such as PTFE or any other plastic material, or Teflon.

[0062] The clamps 52, 54 are each carried by a separate retractable arm 58, 60. Each retractable arm 58, 60 is straight in shape and includes a longitudinal end 58a, 60a hinged to the head 46 or body 50 and an opposite longitudinal end 58b, 60b where the corresponding clamp 52, 54 is located.

[0063] Each clamp 52, 54 may be integrally formed with its corresponding arm 58, 60, but may also be movable along the arm 58, 60 so that the position of each clamp can be adjusted to best accommodate each bucket. The clamps extend in opposite directions generally parallel to the direction of extension of the body 50. The jaws 56 of each clamp 52, 54 lie in planes parallel to one another.

[0064] Each arm 58, 60 can be Figure 4 Move to the expanded position shown in Figure 5 , in the deployed position the arms extend substantially perpendicular to the direction of extension of the main body 50 , and in the stowed position the arms extend parallel to the direction of extension and along the main body 50 .

[0065] The movement of each arm 58, 60 is provided here by two corresponding rods 62, 64. Each first rod 62 extends along the extension direction of the main body 50 and includes a longitudinal end hinged to the end 60a of the arm 60 and an opposite longitudinal end connected to a pulling member that can be accessed or controlled by the user from the proximal end of the endoscope 42. Such a pulling member is, for example, a jack (not shown in the figure). Each second rod 64 extends obliquely between the first rod 62 and the corresponding arm 58, 60 and includes a longitudinal end hinged to the end 60b of the arm and an opposite longitudinal end hinged to the rod 62 near the end of the rod connected to the pulling member.

[0066] When a pulling force according to arrow F1 is applied to the end of each rod 62 connected to the pulling member, the rod 62 moves away from the distal end of the endoscope and drags the rod 64 and the arms 58, 60 together with the rod 62, and then the rod 64 and the arms move away from the distal end of the endoscope. Figure 4 Move to the position in Figure 5 A push according to arrow F2 on each rod 62 enables the arms 58, 60 to be deployed again.

[0067] Preferably, the distance between the clamps 52, 54 corresponds to the distance between CR10 and CR90.

[0068] In use, the endoscope 42 can be inserted through the endoscope port of the turbine in a first step, or through the rear or downstream portion of the turbine in the case of an aft stage. Once inserted and in its deployed position, the endoscope 42 can be used in a second step in the following manner: the first clamp 52 is used to clamp the leading edge 26a of the blade of the disengaged bucket at CR10, while the second clamp 54 is used to pull or push the trailing edge 26b of the adjacent blade at CR90 to reengage the disengaged bucket shroud. Thus, in this second step, the shroud is moved by the combined action of the clamps 52, 54 to bring the shroud from its disengaged position to the desired interlocked engagement position.

[0069] Figures 6 to 13 A second embodiment of an endoscope 42 according to the present invention is shown.

[0070] Endoscope 42 has a generally elongated, preferably cylindrical, shape. It includes a proximal end, which is positioned on the operator's side, and a distal end, which is positioned as close as possible to the blade to be reengaged (only the distal end is shown in the figures). The distal end includes a hook 66. Endoscope 42 also includes means 68, 70, 72, 74, 76, 78 for transmitting a generally axial mechanical force (along the motor axis) between hooks 66.

[0071] exist Figures 6 to 13 In the particular embodiment shown in FIG, the distal end of the endoscope 42 includes two hooks 66. Each of the hooks 66 is configured to bear against a spoiler 24, 28 of the shroud 14, or against the leading edge 26a or trailing edge 26b of the blade. The surface of the hooks 66 is coated with a material that will not damage the blade 16 upon contact. The material may be PTFE or any other plastic material, or Teflon.

[0072] According to Figures 6 to 8In the first variation shown in FIG, two hooks 66 extend in the same plane and are oriented in the same direction relative to the extension direction of the endoscope body 42. According to this variation, the two hooks 66 are configured to bear against the respective spoilers 24, 28 of two adjacent blade shrouds 10 (the blades include blade 10a with detached shroud 14a), thereby exerting a generally axial force on the top portions of both blades. More specifically, the first hook 66a is configured to bear against the upstream spoiler 24 of the detached shroud 14a, and the second hook 66b is configured to bear against the downstream spoiler 28 of the shroud of the adjacent blade, and vice versa. This first embodiment is particularly suitable for slightly inclined gas flow ducts.

[0073] According to Figure 9 In the second variant shown in FIG, the two hooks 66 extend in the same plane and are oriented in opposite directions relative to the extension direction of the body of the endoscope 42. According to this embodiment, the first hook 66a is configured to bear on the leading edge of the blade of the detached blade, and the second hook 66b is configured to bear on the trailing edge of the blade of the adjacent blade, and vice versa.

[0074] According to Figure 10 In the third embodiment shown in FIG, the two hooks 66 extend in substantially vertical planes. Thus, the two hooks 66 are offset by a quarter turn relative to the direction of extension of the main body of the endoscope 42. According to this variation, the first hook 66a is configured to bear against the upstream spoiler 24 of the detached shroud 14a, while the second hook 66b is configured to bear against the trailing edge 26b of the blade of the adjacent bucket 10, and vice versa. This third alternative embodiment is particularly well-suited for strongly inclined gas flow ducts.

[0075] Preferably, as in Figure 7 As shown in FIG, one of the two hooks 66 (eg, the first hook 66a) has a half-moon profile. This ensures the angular position of each of the two hooks 66.

[0076] More preferably, as in Figure 8 and Figure 10 As shown in FIG, one of the two hooks 66a, 66b is slidably mounted relative to the other hook 66b, 66a, and the other hook is fixed relative to the body of the endoscope 42. Figure 11 and Figure 12 In the first alternative embodiment shown in FIG, the means for transmitting axial force between the hooks comprise a cable 68. Preferably, according to this variant, the means for transmitting axial force also comprise a spring 70 which presses against the hooks 66. Figure 12 Such a spring 70 , which can be seen in FIG. 4 , enables the hook 66 to be held in a free, open position when the endoscope 42 is inserted into the turbine.

[0077] The cable 68 is attached at one end to a slidably mounted hook and is intended to be actuated by an operator of the endoscope 42 to apply a generally axial force between the two hooks 66. In the example shown, the cable 68 is attached to the first hook 66a via a planar support, typically via a sliding portion 72 arranged on the first hook 66a.

[0078] According to Figure 13 In the second embodiment shown in FIG, the device for transmitting axial force between the hooks includes an electric motor 74, a screw 76, and a rack 78. The electric motor 74 is integral with one of the two hooks, for example, the second hook 66b in the example shown (which is a fixed hook in this example). The rack 78 is attached to the other hook, for example, the first hook 66a in the example shown. The screw 76 connects the electric motor 74 to the rack 78, thereby enabling axial translation of the first hook 66a relative to the second hook 66b.

[0079] In use, the endoscope 42 can be inserted through the endoscope port of the turbine in a first step, or, in the case of an aft stage, through the aft or downstream portion of the turbine. During this first step, the hook 66 is positioned to bear against the spoiler 24, 28 of the disengaged shroud 14a, or against the leading edge 26a or trailing edge 26b of the blade. Once the endoscope 42 has been inserted and the hook 66 is correctly positioned, the endoscope 42 can be used in a second step by applying a generally axial mechanical force to the hook 66, and thus to the adjacent blade 10, by means of the devices 68, 70, 72, 74, 76, 78, so that the hook 66 is positioned on the adjacent blade. Thus, during this second step, the disengaged shroud 14a is moved by the combined action of the hooks 66 to bring the shroud from its disengaged position to the desired interlocked engagement position.

[0080] Figure 14 and Figure 15 A third embodiment of an endoscope 42 according to the present invention is shown.

[0081] The endoscope 42 comprises a proximal end positioned on the operator's side and a distal end positioned as close as possible to the blade 10A to be reinstalled, of which only the distal end is shown.

[0082] exist Figure 14 and Figure 15 In the particular embodiment shown in FIG, the member 86 is in the form of a roller. The endoscope 42 also includes lighting and viewing means, such as a light source and a camera, which are not shown in the figure for the sake of clarity. Figure 14 and Figure 15. The endoscope 42 also includes a device for rotating the component 86 around the axis X of the component. This rotating device (not shown in the figures) for example includes a braided cable system that connects the component 86 to a crank handle relative to the component. In this case, the rotation of the component 86 around the axis X of the component is performed manually by the operator through the crank. Alternatively, the rotating device may include an electric motor that is directly connected to the component 86 or remotely connected to the braided cable through a spline system. In this case, the component 86 is rotated around the axis X of the component electrically by the motor. Alternatively, the rotating device may include a centrifugal wheel system that is connected to the component 86 and is applied with air pressure. In the latter case, the rotation of the component 86 around the axis X of the component is achieved pneumatically.

[0083] Preferably, member 86 is made of a material that will not damage blades 16 upon contact. This material can be, for example, PTFE or any other plastic material, or Teflon. When member 86 is in the form of a roller, the roller has a generally elliptical shape, which is defined by the turbine stage in which the roller will be used. Preferably, roller 86 has an elliptical shape with a minimum width of approximately 7 mm and a maximum width of between 15 mm and 30 mm. The dimensions of roller 86 are also selected to be compatible with the dimensions of the turbine's endoscope port.

[0084] In use, the endoscope 42 can be inserted in a first step through the endoscope port of the turbine, or in the case of a rear stage through the rear or downstream of the turbine. Figure 14 , the roller 86 is positioned with the smaller width of the roller between two adjacent blades 16 of two buckets 10, of which the bucket 10A includes a detached shroud 14A. To this end, when the roller is inserted through the endoscope 42, the roller 86 exerts a mechanical force on the two blades 16 to separate the two corresponding buckets 10. Once inserted, and as shown in Figure 15 As shown in FIG, endoscope 42 can be used in the following manner in a second step: roller 86 is rotated about its axis X by a rotating device to push the two blades 16 across the greater width of the roller. Roller 86 thus bears on the two blades 16 and pushes them in generally opposite directions D1 and D2. This movement of roller 86 enables the two corresponding buckets 10 to move tangentially, giving the disengaged bucket 10A greater freedom to return to its normal position. Thus, shroud 14A is moved by means of member 86, bringing it from its disengaged position to the desired interlocking engagement position.

[0085] Figure 16 A fourth embodiment of an endoscope 42 according to the present invention is shown.

[0086] The endoscope 42 comprises a proximal end which is positioned on the operator's side and a distal end which must be positioned as close as possible to the blade to be reengaged. Figure 16 Only the distal end is shown in FIG. The distal end includes an inflatable member 88.

[0087] exist Figure 16 In the particular embodiment shown in FIG, the member 88 is in the form of an air cushion. Preferably, the air cushion 88 is made of a flexible, waterproof material such as rubber. The endoscope 42 also includes lighting and viewing devices, such as a light source and a camera, which are not shown in FIG for the sake of clarity. Figure 16 The endoscope 42 further comprises air supply means for supplying air to the inflatable member 88. Such means comprises, for example, an air channel 90 extending axially through the body of the endoscope 42.

[0088] In use, for the aft stage, endoscope 42 can be inserted in a first step through the aft portion or downstream of the turbine of the turbine. In this first step, inflatable member 88 is positioned between two adjacent blades of two blades, one of which includes a disengaged shroud. Once inserted, endoscope 42 can be used in a second step by inflating inflatable member 88 via an air supply. Under the pressure of the air blown into the inflatable member, inflatable member 88 thus bears against the two adjacent blades and biases them in substantially opposite directions. This inflation of member 88 enables the two corresponding blades to move tangentially, which gives the disengaged blade 10A greater freedom to return to its normal position. Thus, the shroud is moved from its disengaged position to the desired interlocked engagement position by the action of member 88.

[0089] An advantage of using such an endoscope 42 with an inflatable member 88 is that the operator is not required to use any special manipulation system for the member 88, but rather simply operate the air supply.

[0090] It will therefore be appreciated that the reinstallation method and reengagement device 40 according to the present invention enable the reinstallation of blade shrouds of a rotor wheel in an aircraft turbomachine without requiring the removal or disassembly of the turbomachine's engine or turbine. This prevents premature removal or dynamic failure of the blades and the engine or turbine. Thus, the method and device according to the present invention maximize and optimize engine utilization while ensuring healthier operation of the mobile blades. Furthermore, the method and device according to the present invention also enable a reduction in costs and the number of repairs required during maintenance operations.

Claims

1. A method for reinstalling blades (10; 10a) and shrouds (14; 14a) of a rotor wheel in an aircraft turbine, the rotor wheel comprising a disk supporting blades (10; 10a), the blades each comprising a blade (16; 26) extending between a root (12) and a shroud, the shroud of each blade comprising a lateral edge (21, 22) having a shape complementary to the lateral edge (21, 22) of the shroud of an adjacent blade, the lateral edges (21, 22) of the shroud being interlocked in such a manner that the anti-wear coatings (36) of these lateral edges contact each other in a desired interlocking engagement position, and at least one of the lateral edges (21, 22) of at least one of the shrouds (14a) being detachable from the lateral edge (21, 22) of the adjacent shroud (14) and being in an undesired detached position, characterized in that The method comprises the steps of inserting a reengagement device (40) into the turbine when such an undesired disengaged position is detected, and moving the at least one shroud (14a) from the undesired disengaged position to the desired interlocked engaged position by bearing the at least one shroud on the or each blade from which the shroud has disengaged or applying a force on the or each blade from which the shroud has disengaged.

2. The method according to claim 1, wherein The reengagement device (40) is inserted through an endoscope port of the turbine or through the aft or downstream portion of the turbine.

3. The method according to claim 1 or 2, wherein: The reengaging device (40) includes an endoscope (42) including an illumination device and a viewing device (48a, 48b), and a clamp (52, 54) or a hook (66, 66a, 66b) configured to cooperate with the blade (16; 26) or the shroud (14; 14a) of one blade (10; 10a) to perform the moving step.

4. The method according to claim 3, wherein: The clamps (52, 54) or the hooks (66, 66a, 66b) are retractable and / or movable relative to each other and / or relative to the endoscope (42).

5. The method according to claim 3, wherein The endoscope (42) includes clamps (52, 54) each configured to grip the leading edge (26a) and / or trailing edge (26b) of the blade, or even the leading edge and / or trailing edge of an adjacent blade, during the moving step.

6. The method according to claim 5, wherein: The endoscope (42) includes a first clamp (52) configured to clamp the leading edge (26a) of the blade and a second clamp (54) oriented in a direction different from that of the first clamp (52) and configured to clamp the trailing edge (26b) of an adjacent blade.

7. The method according to claim 3, wherein: The endoscope (42) includes hooks (66, 66a, 66b), each of which is configured to cooperate with a spoiler (24, 28) of the shroud (14; 14a) and / or the leading edge (26a) or trailing edge (26b) of the blade, or even with the leading edge or trailing edge of an adjacent blade during the movement step.

8. The method according to claim 7, wherein: The endoscope (42) includes a first hook portion (66a) slidably mounted relative to a second fixed hook portion (66b) of the endoscope.

9. The method according to claim 3, wherein: The endoscope (42) includes a movable member (86) that is rotatable about an axis (X), and the method includes engaging the movable member (86) between two adjacent blades (26) and rotating the movable member (86) about the axis (X) during the moving step so that the movable member (86) is supported on the two adjacent blades (26) and biases the two adjacent blades in opposite directions (D1, D2).

10. The method according to claim 3, wherein: The endoscope (42) includes an inflatable member (88), and the method includes engaging the inflatable member (88) between two adjacent blades and inflating the inflatable member (88) during the moving step so that the inflatable member (88) bears on the two adjacent blades and biases the two adjacent blades in opposite directions.

11. The method according to claim 1 or 2, wherein: The reengagement device (40) includes an endoscope (42).

12. The method according to claim 9, wherein The movable member (86) is in the form of a roller.

13. A reengaging device (40) for performing the method according to any one of claims 1 to 12, wherein: The reengagement device comprises an endoscope (42) comprising an illumination device and a viewing device (48a, 48b) and at least one element selected from the group consisting of: - a clamp (52, 54) and / or a hook (66, 66a, 66b) configured to cooperate with the blade (16; 26) or the shroud (14; 14a) of one blade (10; 10a) during a moving step, and - A movable member (86) or an inflatable member (88) configured to engage between two adjacent blades and bias the two adjacent blades in opposite directions.

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