TURBOMACHINE RING

FIELD OF THE INVENTION

This disclosure relates to a turbomachine ring and a turbomachine comprising such a ring and a method of repairing such a ring. It may in particular be a compressor or turbine ring of an aircraft engine, with single or double flow.

STATE OF THE PRIOR ART

In many turbomachine compressors, but also in certain turbines, the fixed vanes are mounted on sectors forming a ring materializing the air stream: these sectors are then mounted on the stator casing using parts hook engaging in notches of a stator support.

[0003] However, during operation of the turbomachine, due in particular to the vibrations undergone by the sectors of the ring, the hooks of the sectors rub and wear out the notches of the support: there is thus sometimes an erosion on the internal faces of the notches . Naturally, such erosion modifies the chains of ribs between the parts of the ring, in particular opening clearances and moving parts, which can lead to leaks and cause loss of performance.

[0004] Therefore, it is desired to be able to repair these notches without replacing the entire support.

[0005] A possible repair option would be to locally recharge the material of the notch, either by thermal spraying, or by welding or brazing. However, such solutions are difficult to achieve due to the difficulty of access to the area to be reworked and the geometry of the area to be reloaded.

Another possible option would be to fix a hoop type element on each face of the notch to be repaired. However, it is difficult to resin the entire vein in this way. Indeed, a resin coating causes too substantial dimensional dispersions; in addition, the temperature resistance of the resins is not sufficient in the context of an application on a turbomachine.

[0007] There is therefore a real need for a turbomachine ring, as well as a turbomachine comprising such a ring and a method for repairing such a ring, which are devoid, at least in part, of the drawbacks inherent in known methods. aforementioned.

PRESENTATION OF THE INVENTION

This disclosure relates to a turbomachine ring, comprising a support, essentially cylindrical, comprising a front surface in which is formed a notch, one or more sectors forming a ring configured to materialize a section of air stream, each sector comprising a hook part projecting towards the support and engaging in the notch of the support, and an anti-wear device having a U-shaped part, provided in the notch of the support and pressed at least against the radially outer surface of the notch, and a tongue part, continuously extending the U-shaped part, pressed against and fixed against the front surface of the support.

[0009] With such an anti-wear device, it is possible to easily and efficiently repair a worn support slot. It is also possible to install such an anti-wear device from the outset in order to facilitate maintenance of the turbomachine. In fact, thanks to such an anti-wear device, in the event of friction or vibrations between the sector and the support, the notch of the support is protected, only the anti-wear device being worn out if necessary. However, the anti-wear device can be replaced easily, which drastically reduces the time and cost of repair.

[0010] In addition, thanks to the part of the tab which is pressed against the front surface of the support, it is possible to effectively maintain the anti-wear device in the pressed position within the notch while offering increased accessibility allowing a easy attachment and removal of the anti-wear device.

[0011] The fact of fixing the anti-wear device on the support also makes it possible to simplify the nomenclature of the parts of the turbomachine and the logistics associated with maintenance: in fact, this makes it possible to avoid assigning an individual reference to the device. anti-wear.

[0012] In some embodiments, the U-shaped portion of the anti-wear device is under elastic stress. This ensures a permanent plating of the U-shaped part against the radially outer surface of the notch.

In some embodiments, the radially inner wall of the U-shaped portion of the anti-wear device forms, at rest, a first angle of between 5 ° and 20 °, preferably between 10 ° and 15 °, with the direction of the radially outer wall of the U-shaped portion. In other words, such an angle appears when the anti-wear device is not inserted into the notch, for example before repair of the support or after its extraction. Such an angle is measured in an axial plane. It makes it possible to generate the elastic stress mentioned above when the anti-wear device is placed in the notch.

[0014] In some embodiments, the tongue portion of the anti-wear device is under elastic stress. This makes it possible to return the U-shaped part of the anti-wear device towards the bottom of the notch, thus stabilizing its position.

In some embodiments, the tongue portion of the anti-wear device forms, at rest, a second angle of between 5 ° and 20 °, preferably between 10 ° and 15 °, with the direction orthogonal to the wall radially outer part of the U-shaped part. In other words, such an angle appears when the anti-wear device is not inserted into the notch, for example before repairing the support or after its extraction. Such an angle is measured in an axial plane. It makes it possible to generate the elastic stress mentioned above when the anti-wear device is placed in the notch.

In some embodiments, the tongue portion of the anti-wear device is, at rest, substantially orthogonal to the radially inner wall of the U-shaped portion.

[0017] In some embodiments, the tongue portion of the anti-wear device continuously extends the U-shaped portion radially inward. Thus, the tongue portion is fixed to the radially inner region of the front surface of the support. This facilitates access to the anti-wear device from inside the ring, helps press the U-shaped portion of the anti-wear device against the radially outer surface of the notch, and protects the front surface of the carrier from friction. with the ring area.

In some embodiments, a space is left between the U-shaped part of the anti-wear device and the bottom of the notch of the support. This space allows a tool to slide between the anti-wear device and the bottom of the notch in order to facilitate the extraction of the anti-wear device.

In some embodiments, a space is left between the U-shaped portion of the anti-wear device and at least a portion of the radially inner surface of the notch of the support. This reinforces the plating of the U-shaped part of the anti-wear device against the radially outer surface of the notch of the support.

[0020] In certain embodiments, the tongue portion of the anti-wear device is fixed to the front surface of the support by fixing points. These fixing points can in particular have a diameter of less than 1 mm, or even 0.5 mm. This facilitates the attachment of the anti-wear device but also its removal, such attachment points being easy to break.

In some embodiments, the attachment points are distributed regularly along the tongue portion of the anti-wear device, in particular in the circumferential direction.

[0022] In some embodiments, at least an angular distance of 15 °, preferably 20 °, separates two attachment points. Moving the fixing points away makes it easier to break the fixing points and therefore to remove the anti-wear device.

[0023] In some embodiments, the tongue portion of the anti-wear device is fixed to the front surface of the support by welding. They may in particular be welding spots by capacitor discharge. The weld in fact withstands the high operating temperatures of the turbomachine and causes only small dimensional dispersions.

In some embodiments, the anti-wear device can be separated from the support under the effect of a manual tearing force. This is a light breakout force for an operator, which allows easy and quick maintenance. In particular, it is possible to separate the anti-wear device by simple leverage by inserting a tool, such as a screwdriver tip for example, between the anti-wear device and the support.

In some embodiments, the thickness of the anti-wear device is between 0.1 mm and 1 mm, preferably between 0.2 mm and 0.6 mm. This is compatible with the usual size of the notches of the turbomachine ring supports.

In certain embodiments, the thickness of the anti-wear device is scalable. Indeed, it is preferable to reserve a greater thickness in the zones of the notch against which the sector is caused to rub and a lower thickness in the other zones to reduce the probability of an unexpected contact with the sector. Thus, in particular, the thickness of the radially inner wall of the U-shaped part of the anti-wear device may be less than the thickness of the radially outer wall of the U-shaped part.

[0027] In certain embodiments, the anti-wear device has a hardness less than that of the support. This allows preferential wear of the anti-wear device relative to the support, thus preserving the support.

In some embodiments, the anti-wear device has a lower hardness than that of the sector hook. This allows preferential wear of the anti-wear device relative to the support hook, thus preserving the support hook.

[0029] In some embodiments, the anti-wear device is made of Inconel.

In certain embodiments, the anti-wear device comprises a base element taking the form of a profile, preferably of the foil type. This foil is preferably metallic. This basic element can have any number of characteristics among those mentioned above.

In some embodiments, the anti-wear device further comprises an additional U-shaped element provided inside the U-shaped portion of the base element. This additional element can have any number of characteristics among those mentioned above. It is thus possible to separate certain functions of the base element and of the additional element and / or to offer a differentiated behavior vis-à-vis the support on the one hand and the sector hook on the other hand. In particular, the base element can perform the mechanical functions of positioning and fixing the anti-wear device while the additional element can provide the preferential wear functions therefore protecting the sector hook and the notch of the support. .

In certain embodiments, the additional element takes the form of a profile, preferably of the foil type, preferably metallic, distinct from the base element. The additional element can therefore be manufactured independently of the base element and then assembled with the latter.

[0033] In some embodiments, the additional element is under elastic stress. This allows the additional element to be pressed against the radially outer surface of the U-shaped part of the base element.

[0034] In certain embodiments, the additional element takes the form of a coating deposited on the base element. The anti-wear device is thus in one piece.

[0035] In certain embodiments, the base element and the additional element form two layers of the same profile, preferably of the foil type. The anti-wear device is thus in one piece.

In some embodiments, the thickness of the additional element is between 0.1 and 0.4 mm, preferably between 0.1 and 0.3 mm.

[0037] In some embodiments, the additional element has a lower hardness than that of the base element. This allows preferential wear of the additional element with respect to the support, the base element retaining greater mechanical strength.

In some embodiments, the additional element is made of an alloy based on nickel and / or cobalt. It may be provided with an anti-wear coating, for example a deposit based on nickel and / or chromium.

In some embodiments, the anti-wear device is sectorized. Each sector can in particular extend over an angular sector of between 30 and 60 °.

[0040] In some embodiments, the sector hook is pressed against the radially outer surface of the anti-wear device. It is understood that this is carried out at least in operation.

[0041] In some embodiments, the ring is part of a compressor, preferably a high pressure compressor. It could also be a turbine ring. It can just as easily be integrated into a single or double flow turbomachine.

This disclosure also relates to a turbomachine, comprising a turbomachine ring according to any one of the preceding embodiments.

This disclosure also relates to a method of repairing a turbomachine ring, the turbomachine ring comprising a support, essentially cylindrical, comprising a front surface in which a notch is formed, said notch having been at least partially eroded. , and one or more sectors forming a ring configured to materialize an air stream section, each sector comprising a hook part projecting towards the support and engaging in the notch of the support, the repair process comprising the following steps: machining of the internal walls of the notch; placing an anti-wear device, having a U-shaped part and a tongue part, in the notch thus machined;

[0044] In certain embodiments, the anti-wear device conforms to any one of the embodiments presented above.

In the present disclosure, the terms "axial", "radial", "tangential", "proximal", "distal" and their derivatives are defined relative to the main axis of the turbomachine; The term “axial plane” means a plane passing through the main axis of the turbomachine and the term “radial plane” means a plane perpendicular to this main axis; a "front" surface fits into a radial plane; finally, the terms “upstream” and “downstream” are defined in relation to the circulation of air in the turbomachine.

The aforementioned characteristics and advantages, as well as others, will become apparent on reading the following detailed description of embodiments of the turbomachine ring and of the proposed method. This detailed description refers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are schematic and are intended above all to illustrate the principles of the disclosure.

In these drawings, from one figure (FIG) to another, identical elements (or parts of elements) are identified by the same reference signs. In addition, elements (or parts of elements) belonging to different exemplary embodiments but having a similar function are identified in the figures by numerical references incremented by 100, 200, etc.

FIG 1 is a sectional plan of a turbomachine according to the description.

FIG 2 is a sectional view of a first example of a turbomachine ring.

FIG 3 is an enlargement of area III of FIG 2.

FIG 4 is a sectional view of the anti-wear device of the first example.

FIG 5 illustrates a second example of an anti-wear device.

DETAILED DESCRIPTION OF EXAMPLE (S) OF IMPLEMENTATION

In order to make the description more concrete, examples of a turbomachine ring are described in detail below, with reference to the accompanying drawings. It is recalled that the invention is not limited to these examples.

FIG 1 shows, in section along a vertical plane passing through its main axis A, a single-flow turbojet 1 according to the description. It comprises, from upstream to downstream according to the circulation of the air flow, a low pressure compressor 3, a high pressure compressor 4, a combustion chamber 5, a high pressure turbine 6, and a low pressure turbine 7.

[0051] FIG 2 illustrates a portion of the stator of the high pressure compressor 4. In this figure, two compressor rings 30 according to a first embodiment are visible. Each compressor ring 30 comprises an upstream ring support 31m and a downstream ring support 31v, generally cylindrical and forming an integral part of the compressor housing 4: they each form a vein wall facing a bladed wheel. Each compressor ring 30 further comprises a crown of ring sectors 32 fixed to the

ring supports 31m, 31v: they complete the air stream wall of the compressor 4 and carry fixed vanes 32a.

Each ring sector 32 is fixed on the ring supports 31m, 31v using hooking devices 33m and 33v provided at each axial end of the ring sector 32.

More precisely, each ring sector 32 comprises at each of its axial ends a hook 34 extending in the direction of the adjacent support 31m, 31v and penetrating into a notch 35 of the support 31m, 31v.

As is best seen in FIG 3, the notch 35 is made in the front surface 36 of each support 31m, 31v: it extends continuously in the circumferential direction; its radially outer walls 35s and radially inner 35p are parallel.

An anti-wear device 40 is placed in this notch 35. The anti-wear device 40, visible in FIG 4 in its initial state at rest, comprises a U-shaped portion 41 and a tongue portion 42. The anti-wear device 40 is a section in the shape of a circular arc extending continuously and invariantly in the circumferential direction: in FIG 4, it is shown in section along a transverse plane, that is to say a plane. axial in the frame of reference of the turbomachine 1. In the present example, the anti-wear device 40 is sectored, each sector extending over an arc of the same length; however, in other examples it could be completely annular, split or not. In the present example, the anti-wear device 40 is made of an alloy based on nickel and / or cobalt provided with

The U-shaped portion 41 comprises a radially outer wall 41d, a bottom wall 41f and a radially inner wall 41p arranged substantially in the shape of a U with respect to each other. More precisely, the bottom wall 41f extends the radially outer wall 41d orthogonally. On the other hand, the radially inner wall, extending the bottom wall 41f, forms a non-zero angle l with respect to the direction of the radially outer wall 41d, that is to say the axial direction. In the present example, this angle l is approximately 12 °.

The tongue portion 42 for its part comprises a single wall extending the radially inner wall 41p of the U-shaped portion 41: it forms an angle m with respect to the direction normal to the radially outer wall 41d, that is, ie with respect to the radial direction. In the present example, this angle m is equal to approximately 12 °.

The U-shaped portion 41 is engaged in the notch 35 while the tongue portion 42 is pressed against and fixed against the radially internal region 36a of the front surface 36 using weld spots 37 produced by discharge of capacitor. As the distance between the ends of the radially outer walls 41d and radially inner 41p of the U-shaped part 41 of the anti-wear device 40 is greater than the width of the notch 35, the U-shaped part 41 is kept under elastic stress within of the notch 35 and its radially outer wall 41d is resiliently pressed against the radially outer surface 35d of the notch 35. In addition, the lengths of the radially outer walls 41d and radially inner 41p of the U-shaped portion 41 of the anti- wear 40 are less than the depth of the

It is then noted that the hook 34 of the sector 32 penetrates into the notch 35 protected by the anti-wear device 40 and is found in the pressed position against the radially outer wall 41d of the U-shaped portion 41 of the anti-wear device 40 during the operation of the turbomachine 1, a space being left between the hook 34 and the bottom walls 41f and radially internal 41p of the U-shaped part 41 of the anti-wear device 40.

An example of a method for repairing a turbomachine according to the description will now be described. Its purpose is to repair a turbomachine 1 in which the notch 35 of one or more supports 31m, 31v of the high pressure compressor 4 has been worn and degraded following the friction of the hook 34 of a sector 32 in the latter. Concretely, in such a worn notch, the dimensions of the notch as well as the surface condition of its internal walls are degraded.

The repair process then comprises a step of machining the internal walls of the worn notch to a sufficient depth to eliminate the defects and smooth the internal walls so as to obtain the original dimensions to a given setback, for example 0.2mm or 0.4mm.

An anti-wear device 40 as described above, and of which the thickness of the walls of the U-shaped portion corresponds to the depth of this determined withdrawal, is then inserted into the notch 35 thus machined in order to restore its initial ribs.

The tongue portion 42 of the anti-wear device 40 is then fixed to the radially internal zone 36a of the front surface 36 by weld spots 37 produced by capacitor discharge.

[0064] The compressor ring 30 is thus repaired.

Once the anti-wear device 40 thus installed, the hook 34 of the sector 32 wears the anti-wear device 40 but no longer damages the notch 35 of the support 31m, 31v.

Therefore, if the anti-wear device 40 reaches an excessively high level of wear, it suffices to remove it and replace it with a new anti-wear device 40 to repair the compressor ring 30. This may s This can be done very easily by inserting a tool into the space 38 between the anti-wear device 40 and the bottom 35f of the notch 35 and by levering it to break the welds 37 step by step. The new anti-wear device 40 can then be placed in the notch 35 and fixed on the front surface 36 in place of the worn anti-wear device 40.

FIG 5 illustrates a second example of a turbomachine ring 130. This second example is quite similar to the first example except that the anti-wear device 140 is different,

In this second example, the anti-wear device 140 comprises a base element 149 and an additional element 159. The base element 149 is shaped completely similar to the anti-wear device 40 of the first example if it is only that its thickness is lower.

The additional element 159 is a section in the form of a circular arc extending continuously and invariantly in the circumferential direction: in FIG 5, it is shown in section along a transverse plan, that is to say an axial plane in the frame of reference of the turbomachine. It takes a U-shape complementary to the U-shaped portion 141 of the base element 149. Thus, at rest, the radially internal wall 15 lp of the additional element 159 also forms an angle l with the direction of its radially wall. external 15 ld, that is to say with the axial direction, so that the additional element is maintained in elastic compression within the base element 149 when the latter is engaged in the notch 135 of the support 131v.

In the present example, the base element 149 of the anti-wear device 140 is made of an alloy based on nickel and / or cobalt while the additional element 159 is made of an alloy based on nickel and / or cobalt: the additional element 159 has a lower hardness both than the base element 159 and the hook 134 of the sector 132.

Although the present invention has been described with reference to specific embodiments, it is obvious that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the revendications. In particular, individual characteristics of the different illustrated / mentioned embodiments can be combined in additional embodiments. Therefore, the description and the drawings should be considered in an illustrative rather than a restrictive sense.

It is also obvious that all the characteristics described with reference to a method can be transposed, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device can be transposed, alone or in combination, to a method.

CLAIMS

1. Turbomachine ring, comprising

a support (31v), essentially cylindrical intended to extend around an axial direction (A) of the turbomachine, the support (31v) comprising a front surface (36) in which a notch (35) is formed, the notch (35) comprising a radially inner surface (35i), a bottom (35f) and a radially outer surface (35d),

one or more sectors (32) forming a ring configured to materialize an air stream section, each sector (32) comprising a hook portion (34) projecting towards the support (31v) and engaging in the notch (35) of the support (31v), and

an anti-wear device (40) having a U-shaped part (41), provided in the notch (35) of the support (31v) and pressed at least against the radially outer surface (35d) of the notch (35), and a tongue part (42), continuously extending the U-shaped part (41), pressed against and fixed against the front surface (36) of the support (31v).

2. Ring according to claim 1, wherein the U-shaped portion (41) of the anti-wear device (40) is under elastic stress.

3. Ring according to claim 1 or 2, wherein the tongue portion (42) of the anti-wear device (40) is under elastic stress.

4. Ring according to any one of claims 1 to 3, wherein a space (38) is left between the U-shaped portion (41) of the anti-wear device (40) and the bottom (35f) of the notch (35). support (31v).

5. Ring according to any one of claims 1 to 4, wherein the tongue portion (42) of the anti-wear device (40) is fixed to the front surface (36) of the support (31v) by welding points. (37).

6. Ring according to claim 5, wherein the solder points (37) are of the type obtained by capacitor discharge.

7. Ring according to any one of claims 1 to 6, wherein the thickness of the anti-wear device (40) is between 0.1 mm and 1 mm, preferably between 0.2 mm and 0.6 mm. .

8. Ring according to any one of claims 1 to 7, wherein the anti-wear device (40) has a hardness less than that of the support (31v) and less than that of the hook (34) of the sector (32).

9. Ring according to any one of claims 1 to 8, wherein the anti-wear device (140) comprises a base member (149), taking the form of a profile having a U-shaped portion (141) and a tongue part (142), and an additional U-shaped element (159) provided inside the U-shaped part (141) of the base element (149),

wherein the additional element (159) has a lower hardness than that of the base element (149).

10. Ring according to claim 9, wherein the additional element (159) takes the form of a profile separate from the base element (149), or of a coating deposited on the base element (149). , or a layer forming the same profile with the base element (149).

11. Turbomachine, comprising a turbomachine ring (30) according to any one of the preceding claims.

12. A method of repairing a turbomachine ring, the turbomachine ring (30) comprising

a support (31v), essentially cylindrical, comprising a front surface (36) in which is formed a notch (35), said notch (35) having been at least partially eroded, and

one or more sectors (32) forming a ring configured to materialize an air stream section, each sector (32) comprising a hook portion (34) projecting towards the support (31v) and engaging in the notch (35) of the support (31v),

the repair process comprising the following steps:

machining of the internal walls of the notch (35);

placing an anti-wear device (40), having a U-shaped part (41) and a tongue part (42), in the notch (35) thus machined; fixing the tongue portion (42) of the anti-wear device (40) to the front surface (36) of the holder (35).