The subject of the disclosed invention is a method for manufacturing turbomachine member ring supports.
The turbomachine member ring supports considered herein extend on truncated conical sectors along a longitudinal axis in a stator and are fitted with a sealing lining on their inner face relative to the longitudinal axis that can be made of an abradable honeycomb material surrounding a circular mobile wheels stage of the machine rotor in order to reduce clearances. The supports have parts for assembly to adjacent stator structures, and particularly a “rail” projecting from their outer face relative to the longitudinal axis.
There are several known methods of manufacturing them. The first is based on forging, but this requires a powerful machine, complex shaped forging dies and hot working that requires precautions to protect the alloy quality, for example preventing the occurrence of mill scale.
Another method uses a welded or brazed assembly of thin plates to form the support. However, the strength of the assembly may be problematic due to large thermal expansions that occur on these parts in service, and manufacturing can be complicated.
A new method is disclosed herein to manufacture such turbine ring supports in which all operations are simple.
In its general form, the invention relates to a method of manufacturing ring supports for a turbomachine member, said supports extending around conical sectors on which a sealing lining is fitted on an inner face and a mounting rail is fitted on an outer face opposite the inner face, the mounting rail including a depression limited by a collar rising along a radially outwards direction from the support, characterised in that it consists of starting from at least one plane metal sheet with a thickness equal to a distance between the inner face and the outer face plus a height of the collar, bending and welding the plate or plates together to form a closed circular cylindrical shroud, bending the cylindrical shroud in tooling to form a conical shroud, machining the outer face of the conical shroud to form the rail on it, and cutting the conical shroud shell to divide it into sectors corresponding to the supports.
In other words, the essential characteristics of the invention are that it starts from thick plates in which the relief of rails is cut, avoiding any assembly of thin plates while minimising corrective machining, and that a support circle is manufactured simultaneously, instead of making these elements separately. This results in several advantages, as will be described later.
The preliminary bending of the plate or plates into a cylindrical shape can be done using a simple deformation tool, as can the next step for pressing and shaping into a conical shape making use of a machine with several concentric jaws. The closed and regular circular shape of the blank thus enables simple machining operations to shape the rail by pressing and then by machining, that can consist of turning.
Note that the bending and shaping operations that do not involve large deformations can be done cold, which simplifies the method and avoids the need to consider the consequences of heating on the final properties of the part.
The different manufacturing methods must respect the dimensions of the requested product. But since the last important operation in this case is machining, it is easy to respect this condition; however, some portions, such as the inner face that is not visible but that is fitted with a sealing lining, can remain unmachined.
It is also easier to manufacture to correct dimensions making use of one important embodiment of the invention in which the jaws and the static ring have biconical profiles symmetric about a median plane, so as to shape a double conical or biconical shroud symmetric on each side of a median plane, which tends to balance applied axial forces and deformations of the tool.
The different aspects of one purely illustrative embodiment of the invention will now be described in more detail with reference to the following figures:
and
We will now give a description of the invention starting with
The next step represented in
It is useful to avoid excessive force unbalances that can occur during this operation, that can be cause of manufacturing dimensions not being respected. The circular shape of the press makes it possible to equalise forces in the angular direction; and unbalanced forces in the axial direction of the shroud 9 or 10 can be cancelled out if the tool is symmetrical on opposite sides of a median plane, as it is in this case, due to the biconical profile of the jaws 11 and the ring 12.
However, it should be noted that all steps of the method can be done cold due to the small deformation applied to the material, both in the bending step (the deformation being distributed over a long length) and the shaping step into a biconical shape.
This shaping by stamping step will usually be made in two passes due to discontinuities between the jaws 11 along the circular row; after a first pass, the biconical shell 10 will be moved by one angular step between jaws 11 corresponding to a few degrees, so as to move each portion of the periphery in front of one of the jaws 11 after each pass (
Replacing the add-on rail 3 by a single-piece portion of the support 19 contributes to improving its cohesion, and it reliably produces correct dimensions. Thus, remachining work is minimised.
Number | Date | Country | Kind |
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14 58079 | Aug 2014 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/FR2015/052275 | 8/26/2015 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2016/030632 | 3/3/2016 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
1625131 | Miller | Apr 1927 | A |
1999482 | Riemenschneider | Apr 1935 | A |
2711659 | Foster | Jun 1955 | A |
3999416 | Brooks | Dec 1976 | A |
4068362 | Spisak | Jan 1978 | A |
4138776 | Oldford | Feb 1979 | A |
4150557 | Walker et al. | Apr 1979 | A |
4361021 | McVay | Nov 1982 | A |
4476194 | Sanborn | Oct 1984 | A |
4770283 | Putz | Sep 1988 | A |
4925365 | Crozet et al. | May 1990 | A |
5031433 | Nishimura | Jul 1991 | A |
5125256 | Ohkubo | Jun 1992 | A |
5228195 | Brown | Jul 1993 | A |
6341938 | Zegarski | Jan 2002 | B1 |
8177493 | Castel | May 2012 | B2 |
8240043 | Duesler | Aug 2012 | B2 |
9587499 | Albers | Mar 2017 | B2 |
9816615 | Stahl | Nov 2017 | B2 |
20090212031 | Stahl | Aug 2009 | A1 |
20140099194 | Johnston et al. | Apr 2014 | A1 |
20150050135 | Grilli | Feb 2015 | A1 |
Number | Date | Country |
---|---|---|
WO1997013612 | Apr 1992 | DE |
10 2011 102 598 | Nov 2012 | DE |
0 356 305 | Feb 1990 | EP |
2 716 873 | Apr 2014 | EP |
2001-221007 | Aug 2001 | JP |
Entry |
---|
Machine Translation of WO1997013612A1 (Year: 1997). |
International Search Report dated Dec. 9, 2015 in PCT/FR2015/052275 filed Aug. 26, 2015. |
French Search Report dated May 26, 2015 in FR1458079 filed Aug. 28, 2014. |
Number | Date | Country | |
---|---|---|---|
20170274441 A1 | Sep 2017 | US |