Turbomachine ring

Abstract

Turbomachine ring as well as a turbomachine comprising such a ring and a method for repairing such a ring, the turbomachine ring comprising an essentially cylindrical support, including a frontal surface wherein a notch is formed, one or more sectors forming an annulus configured to embody a segment of air stream, each sector comprising a hook portion protruding in the direction of the support and engaging in the notch of the support, and an anti-wear device having a U shaped portion, provided in the notch of the support and pressed at least against the radially external surface of the notch, and a tab portion, continuously extending the U shaped portion, pressed and fastened against the frontal surface of the support.

Claims

1. A turbomachine ring, comprising an essentially cylindrical support, provided to extend around an axial direction of a turbomachine, the support including a frontal surface wherein a notch is formed, the notch comprising a radially internal surface, a bottom and a radially external surface, one or more sectors forming an annulus configured to embody a segment of air stream, each sector comprising a hook portion protruding in the direction of the support and engaging in the notch of the support, and an anti-wear device having a U shaped portion formed by a radially internal wall, a radially external wall, and a bottom wall connecting the radially internal wall to the radially external wall, the U shaped portion provided in the notch of the support and pressed at least against the radially external surface of the notch, and a tab portion, continuously extending the U shaped portion, pressed and fastened against the frontal surface of the support, wherein a space is left between the U shaped portion of the anti-wear device and the bottom of the notch of the support, and wherein the U shaped portion of the anti-wear device is under elastic constraint such that a linearly-extending portion of the radially internal wall of the U shaped portion extends towards the bottom of the notch in a direction that forms an angle with an axial direction in which the radially external wall of the U shaped portion extends.

2. The ring according to claim 1, wherein the tab portion of the anti-wear device is fastened to the frontal surface of the support by welding points.

3. The ring according to claim 2, wherein the welding points are formed by capacitor discharge.

4. The ring according to claim 1, wherein a thickness of the anti-wear device is comprised between 0.1 mm and 1 mm.

5. The ring according to claim 1, wherein the anti-wear device has a hardness less than that of the support and less than that of the hook of the sector.

6. The ring according to claim 1, wherein the anti-wear device comprises a base element having the U shaped portion and the tab portion, and an additional element, in the shape of a U, provided in an interior of the U shaped portion of the base element, wherein the additional element has a hardness less than that of the base element.

7. The ring according to claim 6, wherein the additional element takes the form of a section distinct from the base element, or of a layer deposited on the base element, or of a layer forming a same section with the base element.

8. A turbomachine, comprising a turbomachine ring according to claim 1.

9. The ring according to claim 1, wherein the tab portion of the anti-wear device is under elastic constraint.

10. The ring according to claim 9 wherein the tab portion of the anti-wear device is fastened to the frontal surface of the support by welding points.

11. The ring according to claim 10, wherein the welding points are formed by capacitor discharge.

12. The ring according to claim 11, wherein a thickness of the anti-wear device is between 0.1 mm and 1 mm.

13. The ring according to claim 12, wherein the anti-wear device has a hardness less than that of the support and less than that of the hook of the one or more sectors.

14. The ring according to claim 13, wherein, the anti-wear device comprises a base element having the U shaped portion and the tab portion, and an additional element, in the shape of a U, provided in an interior of the U shaped portion of the base element, and wherein the additional element has a hardness less than that of the base element.

15. The ring according to claim 14, wherein the additional element takes the form of a section distinct from the base element, or of a layer deposited on the base element, or of a layer forming a same section with the base element.

16. A turbomachine, comprising a turbomachine ring according to claim 15.

17. A method for repairing a turbomachine ring, the turbomachine ring comprising an essentially cylindrical support, including a frontal surface wherein a notch is formed, said notch having been at least partially eroded, and one or more sectors forming an annulus configured to embody a segment of air stream, each sector comprising a hook portion protruding in the direction of the support and engaging in the notch of the support, the repair method comprising the following steps: machining the internal walls of the notch; placing an anti-wear device having a U shaped portion and a tab portion into the machined notch, the U shaped portion being formed by a radially internal wall, a radially external wall, and a bottom wall connecting the radially internal wall to the radially external wall, a space being left between the U shaped portion of the anti-wear device and a bottom of the notch of the support, and wherein the U shaped portion of the anti-wear device is under elastic constraint such that the radially internal wall of the U shaped portion includes a linear portion that extends towards the bottom of the notch in a direction that forms an angle with a radially internal surface of the notch and an angle with an axial direction in which the radially external wall of the U shaped portion extends; and fastening of the tab portion of the anti-wear device to the frontal surface of the support.

18. A turbomachine ring, comprising an essentially cylindrical support, provided to extend around an axial direction of a turbomachine, the support including a frontal surface wherein a notch is formed, the notch comprising a radially internal surface, a bottom, and a radially external surface, one or more sectors forming an annulus configured to embody a segment of air stream, each sector comprising a hook portion protruding in the direction of the support and engaging in the notch of the support, and an anti-wear device having a U shaped portion formed by a radially internal wall, a radially external wall, and a bottom wall connecting the radially internal wall to the radially external wall by a pair of curved portions at opposite ends of the bottom wall, the U shaped portion provided in the notch of the support and pressed at least against the radially external surface of the notch, and a tab portion, continuously extending the U shaped portion, pressed and fastened against the frontal surface of the support wherein a space is left between the U shaped portion of the anti-wear device and the bottom of the notch of the support; wherein the U shaped portion of the anti-wear device is under elastic constraint such that a linearly-extending portion of the radially internal wall of the U shaped portion extends towards the bottom of the notch in a direction that forms an angle with the radially internal surface of the notch and an angle with an axial direction in which the radially external wall of the U shaped portion extends; wherein the tab portion of the anti-wear device is under elastic constraint; wherein the tab portion of the anti-wear device is fastened to the frontal surface of the support by welding points; wherein the welding points are formed by capacitor discharge; wherein a thickness of the anti-wear device is between 0.1 mm and 1 mm; wherein the anti-wear device has a hardness less than that of the support and less than that of the hook of the sector; wherein the anti-wear device comprises a base element taking the form of a section having a U shaped portion and a tab portion, and an additional element, in the shape of a U, provided in an interior of the U shaped portion of the base element wherein the additional element has a hardness less than that of the base element; and wherein the additional element takes the form of a section distinct from the base element, or of a layer deposited on the base element, or of a layer forming a same section with the base element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The appended drawings are schematic and air intended primarily to illustrate the principles of the disclosure.

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

(3) FIG. 1 is a section plan of a turbomachine according to the disclosure.

(4) FIG. 2 is a section view of a first example of a turbomachine ring.

(5) FIG. 3 is an enlargement of zone III of FIG. 2.

(6) FIG. 4 is a section view of the anti-wear device of the first example.

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

DETAILED DESCRIPTION OF EMBODIMENT(S)

(8) In order to make the disclosure more concrete, examples of turbomachine rings are described in detail hereafter, with reference to the appended drawings. It is recalled that the invention is not limited to these examples.

(9) FIG. 1 shows in section along a vertical plane passing through its main axis A, a single flow turbojet 1 according to the disclosure. It includes, 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.

(10) FIG. 2 illustrates a portion of the stator of the high-pressure compressor 4. In this figure, two compressor ring 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 casing of the compressor 4: each of them forms a stream wall facing an impeller. Each compressor ring 30 also comprises an annular of ring sectors 32 fastened to the ring supports 31m, 31v: they complete the air stream wall of the compressor 4 and carry fixed vanes 32a.

(11) Each ring sector 32 is fastened to the ring supports 31m, 31v by means of hooking devices 33m and 33v provided at each axial end of the ring sector 32.

(12) 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.

(13) As is more visible in FIG. 3, the notch 35 is made in the frontal surface 36 of each support 31m, 31v: it extends continuously in the circumferential direction; its radially external 35s and radially internal 35p walls are parallel.

(14) An anti-wear device 40 is placed in this notch 35. The anti-wear device 40, visible in FIG. 4 in its initial rest state, comprises a U-shaped portion 41 and a tab portion 42. The anti-wear device 40 is a circular arc section extending continuously and invariantly in the circumferential direction: in FIG. 4, it is shown in section along a transverse plane, i.e. an axial plane in the frame of reference of the turbomachine 1. In the present example, the anti-wear device 40 is divided into sectors, each sector extending in 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 a nickel- and/or cobalt-based alloy provided with an anti-wear coating: it has a hardness less than both the support 31m, 31v and the hook 34 of the sector 32.

(15) The U shaped portion 41 comprises a radially external wall 41d, a bottom wall 41f and a radially internal wall 41p arranged substantially in the shape of a U with relative to one another. More precisely, the bottom wall 41f continues the radially external wall 41d orthogonally. By contrast, the radially internal wall, continuing the bottom wall 41f, forms a nonzero angle λ relative to the direction of the radially external wall 41d, i.e. the axial direction. In the present example, this angle λ is approximately 12°.

(16) The tab portion 42 comprises for its part a single wall continuing the radially internal wall 41p of the U shaped portion 41: it forms an angle μ relative to the direction normal to the radially external wall 41d, i.e. relative to the radial direction. In the present example, this angle μ is approximately 12°.

(17) The U shaped portion 41 is engaged in the notch 35 while the tab portion 42 is pressed and fastened against the radially internal zone 36a of the frontal surface 36 by means of welding points 37 accomplished by capacitor discharge. As the distance between the end of the radially external 41d and radially internal 41p walls of the U shaped portion 41 of the anti-wear device 40 is greater than the width of the notch 35, the U shaped portion 41 is maintained under elastic constraint within the notch 35 and its radially external wall 41d is elastically pressed against the radially external surface 35d of the notch 35. Moreover, the lengths of the radially external 41d and radially internal 41p walls of the U shaped portion 41 of the anti-wear device 40 are less than the depth of the notch 35, so that a space 38 remains between the bottom wall 41f of the U shaped portion 41 and the bottom 35f of the notch 35.

(18) 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 located in position pressed against the radially external 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 41f and radially internal 41p walls of the U shaped portion 41 of the anti-wear device 40.

(19) An example of the method of repairing a turbomachine according to the disclosure will now be described. It has as its purpose to repair a turbomachine 1 in which the notch 35 of one or more supports 31m, 31v of the high-pressure compressor 4 have been worn and degraded due to the friction of the hook 34 of a sector 32 in the latter. Concretely, in a worn notch of this type, the dimensions of the notch as well as the surface condition of its internal walls are degraded.

(20) The repair method then comprises a step of machining the internal walls of the worn notch to a sufficient depth to eliminate the faults and smooth the internal wall so as to obtain the original dimensions within a predetermined removal, for example 0.2 mm or 0.4 mm.

(21) An anti-wear device 40 as described above, and in which the thickness of the walls in the U shaped portion corresponds to the depth of this predetermined removal, is then inserted into the notch 35 thus machined in order to restore its original dimensions.

(22) The tab portion 42 of the anti-wear device 40 is then fastened to the radially internal zone 36a of the frontal surface 36 by welding points 37 accomplished by capacitor discharge.

(23) The compressor ring 30 is thus repaired.

(24) Once the anti-wear device 40 is 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.

(25) Henceforth, if the anti-wear device 40 reaches too high a level of wear, it is sufficient to remove it and replace it with a new anti-wear device 40 to repair the compressor ring 30. This can be accomplished very easily by inserting a tool into the space 38 located between the anti-wear device 40 and the bottom 35f of the notch 35 and using it as a lever to break the welding points 37 one after the other. The new anti-wear device 40 can then be installed in the notch 35 and fastened to the frontal surface 36 in place of the worn anti-wear device 40.

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

(27) In this second example, the anti-wear device 140 comprises a base element 149 and an additional element 159. The base element 149 is formed in a manner completely similar to the anti-wear device 40 of the first example, except that its thickness is smaller.

(28) The additional element 159 is a circular arc section extending continuously and invariantly in the circumferential direction: in FIG. 5, it is shown in section along a transverse plane, i.e. an axial plane in the frame of reference of the turbomachine. It takes the shape of a U complementary to the U-shaped portion 141 of the base element 149. Thus, at rest, the radially internal wall 151p of the additional element 159 also forms an angle λ with the direction of its radially external wall 151d, i.e. with the axial direction, in such a manner that the additional element is retained in elastic compression within the base element 149 when the latter is engaged in the notch 135 of the support 131v.

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

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

(31) It is also obvious that all the features described with reference to a method are transposable, alone or in combination, to a device, and conversely, all the features described with reference to a device are transposable, alone or in combination, to a method.