Tool system for controlling a zone of a blade root

Abstract

The invention relates to a tool system for controlling a zone (70) of at least one face of a cavity (94A, 94B) of a turbomachine turbine blade (90). This tool system consists of at least one tool (10), a portion of which is capable of exactly fitting the zone (70) on at least the perimeter (71) of said zone (70) when the at least one tool (10) is in a position of contact with the blade (90).

Description

Description Title: Blade root zone control tool

[0001] In a turbomachine, for example a double-spool turbomachine extending along a longitudinal axis, an upstream compressor compresses the air that has entered the turbomachine from upstream. This air is admitted into the combustion chamber of the turbomachine located downstream where it is mixed with fuel before being burned. The hot gases resulting from this combustion are then expanded in a turbine located downstream and turn this turbine. The rotation of this turbine drives the rotor of this turbomachine on which these turbines are mounted. The rotor in turn drives the rotation of the compressor and the fan blades located upstream of the turbomachine. The rotation of the fan blades contributes, with the high-speed ejection of the gases at the outlet of the combustion chamber, to the propulsion of the turbomachine.

[0002] The turbine and the compressor comprise a set of coaxial discs which are arranged one after the other along the longitudinal axis of the turbomachine. Each disc carries at its outer periphery a plurality of movable blades 90 regularly distributed at this outer periphery. The movable blades 90 have a platform 91 which extends circumferentially and which is extended radially internally by a blade root 92 and extended radially externally by a blade 93. The end of the root 92 of each blade 90 is housed in a cell of the disc, each cell opening onto the outer peripheral surface of the disc. A cell has a shape which substantially matches the shape of this root end 92. This end has a shape which allows it to be held in its cell despite the centrifugal force which is exerted on the blade 90 during the rotation of the disc during operation of the turbomachine.Between this end and the platform, the foot 92 comprises a stilt 94 of complex shape with a radial median wall 95 which has an intrados face 95A and an extrados face 95B. The intrados face 95A (respectively extrados face 95B) delimits with the platform 91 an intrados cavity 94A (respectively extrados cavity 94B).

[0003] Shock absorbers are housed in each of these cavities (94A, 94B). In operation, these shock absorbers can leave marks (called imprints) on the faces of this intrados cavity 94A and this extrados cavity 94B. This situation is illustrated in Figure 6A and Figure 6B. Figure 6A illustrates the intrados cavity 94A which is delimited by Péchasse 94 of a foot 92 of a blade 90 and by the platform 91 of this blade 90. Figure 6B illustrates the extrados cavity 94B which is delimited by Péchasse 94 and by the platform 91. The faces of the intrados cavity 94A and of the extrados cavity 94B have indentations 80. When the depth of these indentations 80 is greater than a threshold value and these indentations are located in a zone 70, these indentations 80 are undesirable. Indeed, these indentations 80 then weaken the blades 90 which are subjected to high mechanical and thermal stresses. For example, this threshold value is equal to 0.02 mm.The zone 70 is indicated schematically in figures 6A and 6B. This zone 70 covers for example the radially upper part of Péchasse 94 (in particular of the middle wall 95) and the lower face of the platform 91. When marks 80 deeper than this threshold depth are present in the zone 70, the part must be discarded. When inspecting the blades 90, it is therefore necessary to check whether the impressions 80 which are present on the walls of the intrados 94A and extrados 94B cavities are located in the zone 70 or outside this zone 70. Currently this zone 70 is measured manually using a ruler.

[0004] Thus, there is known a tool for controlling an area of ​​at least one face of a cavity of a turbomachine turbine blade comprising a platform and a foot with a stilt, the cavity being delimited by Péchasse and the platform.

[0005] This control is complex and tedious on the one hand because the blades 90 are small for handling by an operator (the maximum dimension is a few centimeters), on the other hand because the shape of Péchasse 94, the shape of the middle wall 95 and the shape of the platform 91 are complex because they include curves, protuberances, low walls, hollows. Furthermore, the zone 70 to be controlled is not horizontal but inclined, which makes the control more difficult. In addition, a large number of blades must be controlled in a shortest possible time, for example more than a hundred blades for a turbine stage. Description of the invention

[0006] The present invention aims to remedy these drawbacks.

[0007] The invention aims to provide a tool which allows practical and rapid control of the blade roots.

[0008] This aim is achieved by the fact that the tooling consists of at least one tool, a portion of which is capable of exactly matching the zone over at least the perimeter of the zone when the at least one tool is in contact position with the blade.

[0009] Thanks to these provisions, the operator knows quickly and precisely whether a print is located, partially or entirely, in the critical zone or not. The tooling ensures that the requested control will be compliant and identical for all operators. The tooling also helps avoid errors, and makes the requested control more visual and therefore easier.

[0010] For example, the at least one tool furthermore exactly matches the area over the entire interior of the area.

[0011] For example, at least one tool has a handle that allows it to be gripped.

[0012] For example, the at least one tool comprises a first tool which is capable of covering a first portion of the area and comprises a second tool distinct from the first tool which is capable of covering a second portion of the area complementary to the first portion.

[0013] For example, the first tool comprises a first handle and the second tool comprises a second handle, the handles being opposite each other when said first tool and the second tool are in contact position with the workpiece.

[0014] For example, the tool includes a mechanism for aligning the first handle with the second handle.

[0015] For example, the first handle has a first hole, the second handle has a second hole, these holes aligned when the first tool and the second tool are in contact position with the workpiece, and the alignment mechanism being a rod adapted to be inserted into the holes.

[0016] For example, the platform and Péchasse delimit an intrados cavity and an extrados cavity separated by a median wall, and the first part of the zone is a portion of the face of the intrados cavity and the second part of the zone is a portion of the face of the extrados cavity.

[0017] For example, at least one tool is transparent.

[0018] For example, at least one tool is openwork.

[0019] The invention also relates to a method for controlling an area of ​​a turbomachine turbine blade comprising indentations, the area comprising a first part with a perimeter and a second part with a perimeter which is complementary to the first part, the blade comprising a platform and a root with a stilt, the platform and the stilt delimiting an intrados cavity and an extrados cavity separated by a median wall, the first part being a portion of the face of the intrados cavity and the second part being a portion of the face of the extrados cavity.

[0020] According to the invention, the method comprises the following steps: (a) A tool is provided consisting of a first tool and a second tool distinct from the first tool; (b) The first tool is positioned such that it exactly fits the first part over at least its perimeter and the second tool is positioned such that it exactly fits the second part over at least its perimeter; (c) It is checked whether at least one of the prints is covered or surrounded by the tool at least partially; (d) It is checked whether the depth of at least one of the at least one prints in step (c) is greater than a threshold value; (e) The blade is discarded if the condition in step (d) is verified.

[0021] For example, the first tool further exactly fits the first part over the entire interior of the first part and such that the second tool further exactly fits the second part over the entire interior of the second part.

[0022] The invention will be better understood and its advantages will appear better on reading the detailed description which follows, of embodiments shown as non-limiting examples. The description refers to the appended drawings in which:

[0023] [Fig. 1] Figure 1 is a longitudinal sectional view of a turbomachine.

[0024] [Fig. 2] Figure 2 is a sectional view of the low pressure turbine 7 of the turbomachine of Figure 1.

[0025] [Fig. 3] Figure 3 is: In (A), a view of the intrados face of a blade of the low pressure turbine of Figure 3; In (B), a view of the extrados face of a blade of the low pressure turbine of Figure 2.

[0026] [Fig. 4] Figure 4 is: In (A), a view of the blade illustrated in Figure 3A equipped with the tooling according to the invention; In (B), a view of the blade illustrated in Figure 3B equipped with the tooling according to the invention.

[0027] [Fig. 5] Figure 5 is: At (A), a view of the tooling illustrated in Figure 4A; At (B), a view of the tooling illustrated in Figure 4B.

[0028] [Fig. 6] Figure 6, already described, is: In (A), a view of the intrados face of a blade; In (B), a view of the intrados face of a blade. Detailed description of the invention

[0029] We consider a turbomachine 1 with a longitudinal axis X which is its axis of rotation. In the description below, the terms "internal" and "inner" designate an element oriented towards the longitudinal axis X or arranged closer to this axis. The terms "external" and "outer" designate an element oriented in the opposite direction from the longitudinal axis X or arranged further from this axis. The terms "upstream" and "downstream" are relative to the direction of circulation of the air and gases during operation of the turbomachine, i.e. from left to right in the figures. The term "radial" designates a position or a direction in a transverse plane perpendicular to the longitudinal axis X.

[0030] The invention is described below for blades mounted on the discs of the two stages of the low pressure turbine which are located furthest upstream (see below). However, the invention is valid for any blade with a root comprising a stilt, an area of ​​which must be visually inspected for the presence or absence of defects.

[0031] By way of example, the invention is described in the case where the turbomachine 1 is a dual-flow twin-spool turbomachine. Figure 1 illustrates such a turbomachine 1, in a longitudinal view. This turbomachine 1 comprises a nacelle 2 with a fan 3 comprising blades. The turbomachine 1 comprises a hub 8a, a rotor element of which carries the ring of blades forming the propeller of the fan 3. The hub 8a is made up of rotor elements and stator elements alternating along the longitudinal axis X. The hub 8a is carried by a rotor 8 which extends along the longitudinal axis X and which is rotated by a high-pressure turbine 6 and a low-pressure turbine 7, discussed below. Radially outside the hub 8a and downstream of the propeller of the fan 3 is an internal casing 8b which is coaxial with the hub 8a.

[0032] In normal operation of the turbomachine 1, an air flow (called secondary flow F2) circulates in an annular vein, called second vein V2, which extends between the inner casing 8b and the nacelle 2. Another annular vein, called first vein V1, extends between the hub 8a and the inner casing 8b. The first vein V1 comprises, downstream of the fan 3, a compressor 4 and a combustion chamber 5. This compressor 4 comprises, upstream, a low-pressure compressor 4a and downstream, a high-pressure compressor 4b. The air compressed by the compressor 4 is admitted downstream into the combustion chamber 5 and mixed with fuel before being burned there. The hot gases resulting from this combustion are then expanded in a turbine in the first vein V1 and turn this turbine. This turbine comprises a high-pressure turbine 6 which is located downstream of the combustion chamber 5 and then a low-pressure turbine 7 located downstream of the high-pressure turbine 6.The high pressure turbine 6 comprises at least one stage E and the low pressure turbine 7 comprises several stages E, each stage E consisting of a crown (row) of fixed turbine blades, also called a nozzle, followed by a crown (row) of moving turbine blades. spaced circumferentially all around the longitudinal axis X. The stages E are located in the first vein V1. The turbomachine 1 also comprises a rotor 8 whose axis of rotation is the longitudinal axis X. The movable turbine blades of the high pressure turbine 6 and of the low pressure turbine 7 are integral with the rotor 8. Indeed, a row of blades is mounted on the entire external circumference of a disk which is itself mounted on the rotor 8, such that each blade extends radially outwardly relative to the disk. Thus, the rotation of these movable turbine blades rotates the rotor 8 which in turn drives the low pressure compressor 4a, the high pressure compressor 4b and the blades of the fan 3 in rotation. The rotation of the blades of the fan 3 contributes, with the high-speed ejection of the gases at the outlet of the combustion chamber 5, to the propulsion of the turbomachine 1.The assembly of blades on the external circumference of discs described above for the turbines (6, 7) is found at the level of the compressor 4.

[0033] Figure 2 illustrates a portion of the low-pressure turbine 7, which shows the blades of the stages E with the RF rings of fixed turbine blades and the RM rings of mobile turbine blades 90. Each mobile blade 90 has a platform 91 which extends circumferentially and which is extended radially internally by a blade root 92 and extended radially externally by a blade 93. The end of the root 92 of each blade 90 is housed in a cell of the disk, each cell opening onto the outer peripheral surface of the disk. A cell has a shape which substantially matches the shape of this end of root 92. This end has a shape which allows it to be held in its cell despite the centrifugal force which is exerted on the blade 90 during the rotation of the disk during operation of the turbomachine.

[0034] Figure 3A and Figure 3B illustrate in detail the root 92 and the platform 91 of a blade 90. Figure 3A is a view of the intrados portion of the blade 90 and Figure 3B is a view of the extrados portion of the blade 90. The root 92 of the blade 90 comprises a stilt 94 of complex shape with a radial median wall 95 which has an intrados face 95A and an extrados face 95B. The intrados face 95A (respectively extrados face 95B) delimits with the platform 91 an intrados cavity 94A (respectively extrados cavity 94B).

[0035] Dampers are housed in each of these cavities (94A, 94B). In operation, these dampers can leave impressions 80 on the faces of these cavities (94A, 94B). When the depth of these impressions 80 is greater than a threshold value and these impressions are located in a critical zone 70, these impressions 80 are undesirable. This critical zone 70 covers for example the radially upper part of Péchasse 94 (in particular of the middle wall 95) and the lower face of the platform 91. The zone 70 comprises a perimeter 71 and an interior 72 which covers this zone 70 and which is surrounded by this perimeter 71.

[0036] To check whether an imprint 80 is located in the zone 70, a control tool is used which is made up of at least one tool 10, a portion of which is capable of exactly matching the zone 70 over at least its perimeter 71 when this tool 10 is in the position of contact with the part 90. By “exactly matching the zone 70 over a region”, it is meant that this portion of the tool 10 which is in contact with the part 90 (in a contact position) does not match the part 90 outside this zone 70. This portion of the tool 10 therefore matches this zone 70 over this region of this zone 70. This region may be part or all of this zone 70. In the present case, the portion of the tool 10 matches the zone 70 over its perimeter 71 and possibly over part or all of the interior 72 of this zone 70.Thus, the operator who positions the tooling on the blade 90 is immediately able to determine whether an imprint 80 is located, partially or entirely, inside the zone 70 or outside this zone 70. The control tooling is intended to be used only when the part 90 is removed from the turbine and the engine.

[0037] For example, the portion of the tool 10 which is in contact with the blade 90 fits the zone 70 only on its perimeter 71. Alternatively, the portion of the tool 10 which is in contact with the part 90 fits the zone 70 on its perimeter 71 and on the entire interior 72. Thus, this portion of the tool 10 covers exactly the entire zone 70.

[0038] For example, tool 10 is a shell, i.e. a three-dimensional element of which one dimension (thickness) is small (at least ten times, for example at least twenty times, for example at least fifty times) compared to its two other dimensions.

[0039] Advantageously, the tool 10 is transparent, so that it is possible to see the prints 80 through the tool 10. This makes it easier to check the position of the prints 80 relative to the area 70. In other words, the tool 10 is made, in part or entirely, of a transparent material.

[0040] Optionally, the tool 10 includes a handle 30 which allows it to be gripped by an operator. Handling of the tool 10 is thus facilitated.

[0041] Advantageously, the tool 10 is perforated. In other words, the tool 10 has a plurality of disjointed holes which are distributed over part or all of the tool 10 such that it is possible to see portions of the area 70 through these holes. It is thus more practical for the operator to check the position of the impressions 80 relative to the area 70. The non-perforated region of the tool 10 is connected in the mathematical sense of the term, that is to say that the tool 10 is in one piece, which allows it to be gripped with one hand.

[0042] In some cases, the zone 70 comprises a first part 70A and a second part 70B complementary to the first part 70A such that the zone 70 can be divided into the first part 70A and the second part 70B. In this case, the tool 10 consists of a first tool 10A which is capable of covering this first part 70A and a second tool 10B which is distinct from the first tool 10A which is capable of covering this second part 70B. The first part 70A (respectively second part 70B) has a perimeter 71A (respectively perimeter 71B) and an interior 72A (respectively interior 72B) which is surrounded by this perimeter 71A (respectively perimeter 71B). In this case, when the tool 10 is optionally perforated, each of the tools (10A, 10B) is perforated as indicated above.

[0043] The first part 70A of the zone 70 is a portion of the face of the intrados cavity 94A and the second part 70B of the zone 70 is a portion of the face of the extrados cavity 94B, as illustrated in FIGS. 3A and 3B. In this case, the tool 10 comprises a first tool 10A which is capable of covering the first part 70A and a second tool 10B, distinct from the first tool 10A, which is capable of covering the second part 70B.

[0044] Figures 4A and 4B show the blade 90 illustrated in Figures 3A and 3B respectively with the first tool 10A which is positioned in contact position on the first part 70A and the second tool 10B which is positioned in contact position on the second part 70B.

[0045] When the tool 10 is in two parts and comprises a handle 30, the first tool 10A comprises a first handle 30A and the second tool 10B comprises a second handle 30B. This situation is illustrated in FIGS. 4A and 4B in the case where the part 90 is a blade. These handles (30A, 30B) are opposite each other when the first tool 10A and the second tool 10B are in contact position with the blade 90. Optionally, these handles (30A, 30B) are then in contact. As illustrated in FIGS. 4A and 4B, these handles (30A, 30B) are located on a Péchasse edge 94 of the blade 90.

[0046] Figures 5A and 5B show the first tool 10A and the second tool 10B alone, in the contact position. In Figure 5A the first tool 10A and the second tool 10B are seen from the intrados side of the blade 90, in Figure 5B the first tool 10A and the second tool 10B are seen from the extrados side of the blade 90.

[0047] Optionally, the tool 10 includes a mechanism for aligning the first handle 30A with the second handle 30B.

[0048] For example, the first handle 30A has a first relief 31A and the second handle 30B has a second relief 31B which cooperates with the first relief 31A when the first tool 10A and the second tool 10B are in contact position with the part 90. For example, one of these reliefs (31A, 31B) is a male element, the other of these reliefs (31A, 31B) is a female element. The alignment mechanism is then constituted by these reliefs (31A, 31B) because the cooperation between these reliefs (31A, 31B) allows the alignment of the handles (30A, 30B). This cooperation facilitates the use of the tool 10.

[0049] Alternatively, as illustrated in Figures 4A, 4B, 5A and 5B, the first handle 30A has a first hole 32A and the second handle 30B has a second hole 32B. These two holes are aligned when the first tool 10A and the second tool 10B are in contact position with the workpiece 90. The mechanism alignment rod is then an alignment rod 33 (visible in figures 5A and 5B) which is able to be inserted into the holes (32A, 32B).

[0050] The tool 10 is manufactured by any means. For example, the tool 10 is manufactured by molding, for example by 3D printing. The tool 10 is for example made of polymer, for example polyurethane (TPU).

[0051] The invention also relates to a method for inspecting a zone 70 of a blade 90 of which Péchasse 94 comprises impressions 80 using a tool as described above. In particular, this inspection method relates to a zone 70 comprising a first part 70A which is a portion of the face of the intrados cavity 94A of Péchasse 94 and a second part 70B which is a portion of the face of the extrados cavity 94B of complementary Péchasse 94. In a first step (a), a tool 10 is provided consisting of a first tool 10A and a second tool 10B as described above. Then in a step (b) the first tool 10A is positioned such that it exactly matches the first part 70A over at least its perimeter 71A and the second tool 10B is positioned such that it exactly matches the second part 70B over at least its perimeter 71B.Then in a step (c) it is checked whether at least one of the indentations 80 is covered or surrounded by the tool 10 at least partially. Then in a step (d) it is checked whether the depth of the indentation 80, or of at least one of the indentations 80, identified in step (c) is greater than a threshold value which is the maximum authorized value. If the condition in step (d) is verified (i.e. if the depth of at least one indentation 80 is greater than this threshold value), the blade 90 is discarded in a step (e), i.e. it is scrapped or sent for repair.

[0052] In particular, the first tool 10A further exactly matches the first part 70A over its entire interior 72A and the second tool 10B further exactly matches the second part 70A over its entire interior.

Claims

Claims

1. Tool for inspecting an area (70) of at least one face of a cavity (94A, 94B) of a turbomachine turbine blade (90) comprising a platform (91) and a foot (92) with a stilt (94), said cavity (94A, 94B) being delimited by said stilt (94) and said platform (91), said tool being characterized in that it consists of at least one tool (10) a portion of which is capable of exactly matching said area (70) over at least the perimeter (71) of said area (70) when said at least one tool (10) is in the contact position with said blade (90).

2. Control tool according to claim 1 such that said at least one tool (10) further exactly matches said zone (70) over the entire interior (72) of said zone (70).

3. Control tool according to claim 1 or 2 such that said at least one tool (10) comprises a handle (30) which allows it to be gripped.

4. Control tool according to any one of claims 1 to 3 such that said at least one tool (10) comprises a first tool (10A) which is capable of covering a first part (70A) of said zone (70) and comprises a second tool (10B) distinct from said first tool (10A) which is capable of covering a second part (70B) of said zone (70) complementary to said first part (70A), the interior (72) of said zone (70) being the meeting of the interior (72A) of said first part (70A) and the interior (72B) of said second part (70B).

5. Control tool according to claim 4 such that said first tool (10A) comprises a first handle (30A) and said second tool (10B) comprises a second handle (30B), said handles (30A, 30B) being opposite when said first tool (10A) and said second tool (10B) are in contact position with said part (90).

6. Inspection tool according to claim 5 such that said tool (10) comprises a mechanism for aligning said first handle (30A) with said second handle (30B).

7. Control tool according to claim 6 such that said first handle (30A) has a first hole (32A), said second handle (30B) has a second hole (32B), said holes (32A, 32B) being aligned when said first tool (10A) and said second tool (10B) are in contact position with said part (90), and said alignment mechanism being a rod (33) capable of being inserted into said holes (32A, 32B).

8. Inspection tool according to any one of claims 4 to 7 such that said platform (91) and said stilt (94) delimit an intrados cavity (94A) and an extrados cavity (94B) separated by a median wall (95), and such that said first part (70A) of said zone (70) is a portion of the face of said intrados cavity (94A) and said second part (70B) of said zone (70) is a portion of the face of said extrados cavity (94B).

9. Control tool according to any one of claims 1 to 8 such that said at least one tool (10) is transparent.

10. Control tool according to any one of claims 1 to 9 such that said at least one tool (10) is perforated.

11. Method for controlling a zone (70) of a turbomachine turbine blade (90) comprising indentations (80), said zone (70) comprising a first part (70A) with a perimeter (71A) and a second part (70B) with a perimeter (71B) which is complementary to said first part (70A), said blade (90) comprising a platform (91) and a root (92) with a stilt (94), said platform (91) and said stilt (94) delimiting an intrados cavity (94A) and an extrados cavity (94B) separated by a median wall (95), said first part (70A) being a portion of the face of said intrados cavity (94A) and said second part (70B) being a portion of the face of said extrados cavity (94B), said method being characterized in that it comprises the following steps: (a) A tool (10) is provided consisting of a first tool (10A) and a second tool (10B) separate from said first tool (10A); (b) said first tool (10A) is positioned such that it exactly matches said first part (70A) over at least its perimeter (71 A) and said second tool (10B) is positioned such that it exactly matches said second part (70B) on at least its perimeter (71 B); (c) It is checked whether at least one of said prints (80) is covered or surrounded by said tool (10) at least partially; (d) It is checked whether the depth of at least one of said at least one imprint (80) in step (c) is greater than a threshold value; (e) Said blade (90) is moved away if the condition in step (d) is verified.

12. The method of claim 11 such that said first tool (10A) further exactly matches said first portion (70A) over the entire interior (72A) of said first portion (70A) and such that said second tool (10B) further exactly matches said second portion (70A) over the entire interior (72B) of said second portion (70B).

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