The present disclosure relates to the field of the aircraft turbine engine casings.
The present disclosure relates in particular to the manufacture of a casing for a turbine engine, in particular of an aircraft, as well as to tools for the implementation of this method.
The prior art comprises in particular the document EP-A2-2 116 695.
The fan casing 3 is connected to an air inlet duct 5 on the one hand and to an intermediate casing shell 6 on the other. It also carries upstream acoustic panels 7 and downstream acoustic panels 8. The fan casing 3 further comprises an abradable support layer 4, positioned on an internal face 34 of the fan casing 3, between the area comprising the upstream acoustic panels 7 and the area comprising the downstream acoustic panels 8.
In addition to the retention function, the fan casing 3 is also designed to:
It is known that the body of the fan casing is manufactured of a composite material from woven fibers and embedded in a polymeric resin, the manufacturing method being of the “RTM” (Resin Transfer Molding) type. The use of such a method is particularly advantageous because it allows to produce parts with a lower overall mass than these same parts when they are manufactured of metallic material, while having a mechanical strength that is at least equivalent, if not superior.
However, a deformation from the theoretical nominal geometry can be observed at the outlet of the mold, i.e. when the manufactured part (the casing) is extracted. In the case of an annular fastening flange of the fan casing, a defect in relation to a theoretical circular geometry can be observed, for example in the form of the appearance of an ovality of this flange when it is extracted from the mold. For example,
Such defects can in particular be explained by the fact that residual stresses are applied to the part during its manufacture inside the mold (e.g. polymerization gradient, winding tension for a part made of composite material), and are released when the part is extracted from the mold, thus leading to a deformation of the extracted part.
In order to overcome this disadvantage, it is known to use at least one mold comprising a molding cavity whose geometry does not correspond to the nominal geometry of the part to be manufactured but to a geometry for which the deformation has been taken into account, so that when this part is extracted from the mold, the nominal geometry of the part is finally obtained. Such a method can certainly allow to compensate for the deformation of a part of revolution at the outlet of the mold. However, during the manufacture of a fan casing, the observed deformation thereof does not only occur during its extraction from the mold. The manufacture of the casing involves various successive operations, such as machining operations (e.g. trimming, drilling) and bonding (of the abradable layer or acoustic panels for example) operations.
The machining operations lead to the release of physical stresses that can cause deformations of the casing. The bonding operations are usually carried out in an autoclave. These bonding operations involve steps of heating and pressurizing the casing, followed by a step of cooling it. All of these steps also lead to the emergence of stresses acting on the deformation of the flanges of the casing. Various deformations of the casing can therefore occur throughout its manufacturing process and tend to accumulate. The prior art appears to be insufficient to counteract the deformation of the fan casing during its manufacture, since the emergence of this deformation does not only occur during the extraction of the casing from its molding cavity but also during the machining and bonding steps.
The present disclosure provides a solution to limit the risk of deformation of the fastening flanges of a fan casing during the bonding of an abradable annular layer.
During this operation, the casing is housed into an autoclave and a portion of a pressurization system is mounted inside the casing for applying a pressure to the abradable layer radially from the inside to the outside. This system is relatively cumbersome and prevents the use of solutions known in the prior art, such as that of the document FR-A1-3 060 438, consisting of providing several annular parts (rims, flasks, drums, bladders, etc.) inside the casing, which occupy all the space in the casing.
The present disclosure provides a simple, effective and economical solution to this problem.
The disclosure thus proposes a method for manufacturing a casing of an aircraft turbine engine, this casing comprising:
The method according to the disclosure comprises, prior to the step b) of heating and compressing the casing, a step a) of mounting at least two shaping tools between the flanges, each of the tools being located in a circumferential area outside the annular body of the casing so as to exert bearing forces in opposite axial directions on these flanges.
The bearing forces exerted on the flanges by the tool are intended to elastically deform at least one of the flanges so that the displacements thus obtained compensate for the deformations which will be exerted during the bonding step b). These deformations referred to as correction deformations only reposition the flanges in their original positions and shapes. Advantageously, the tools are less bulky and the tools are arranged on the outer surface of the casing. This allows, on the one hand, easy handling and movement of each tool between the circumferential areas of the annular body of the casing, and on the other hand, does not interfere with the bonding operation during which the annular body may be traversed by a portion of the system necessary for heating and/or pressurizing the casing during the step b).
The method according to the disclosure may comprise one or more of the following characteristics, considered independently or in combination with each other:
The present disclosure further relates to tools configured for the implementation of the method according to any of the features of the disclosure, each of the tools comprising:
Each shaping tool according to the disclosure may comprise one or more of the following characteristics, taken alone from each other or in combination with each other:
The disclosure will be better understood and other details, characteristics and advantages of the present disclosure will become clearer from the following description made by way of non-limiting example and with reference to the attached drawings, in which:
By convention in the present application, the terms “inner” and “outer”, and “internal” and “external” are used in reference to a positioning with respect to an axis A of rotation of a turbine engine. Thus, a cylinder extending along the axis A of the engine comprises an inner face directed to the axis of the engine and an outer surface opposite its inner surface. “Longitudinal” or “longitudinally” is defined as any direction parallel to the axis A, and “transversally” or “transverse” is defined as any direction perpendicular to the axis A. Similarly, the terms “upstream” and “downstream” are defined with respect to the direction of the airflow in the turbine engine.
In the following description, the disclosure is applied to a fan casing 3, as illustrated in
This casing 3 to which the method according to the disclosure is applied, comprises an annular body 30 extending about an axis A of revolution. The casing 3 comprises an annular fastening flange, upstream 31 and downstream 32 respectively, extending radially outwards at each of the axial ends of its annular body 30.
In the illustrated example, the casing 3 further comprises an annular layer 4 of abradable material arranged within the body 30, and covering a first internal annular surface 34 of an intermediate section 33 of the body 30.
The body 30 of the casing may be made of a composite material comprising woven fibers and embedded in a resin.
The annular layer 4 is configured to be attached by bonding to the first internal surface 34 of the body 30 of the casing. As mentioned above, during this bonding step, the casing 3 is heated and compressed and may cause a deformation of the flange 31, 32. The flanges 31, 32 generally slope towards the body 30 which is the most massive element of the casing 3. For example, the deformation of the upstream flange 31 is manifested a sloping towards downstream of the external periphery of the flange 31, while the external periphery of the downstream flange 32 slopes towards upstream (
In order to avoid this deformation, the disclosure proposes a specific tool 10 which is arranged outside the casing 3 and which allows to shape the casing 3 during the bonding operation, during which the casing 3 is subjected to a thermal treatment under pressure. Indeed, the tool 10 allows to compensate these deformations by exerting on the flanges 31, 32, prior to the heating and compression operation of the casing, bearing forces (double arrow in
Each plate 11, 12 is connected to at least two connecting rods 13, 14. In
Furthermore, the tool 10 comprises a system 15 allowing an adjustment of the lengths of the rods 13, 14 between the plates 11, 12. The system 15 may comprise the rods of one of the plates, in particular the rods 14 of the second plate 12 in
Advantageously, at least one of the plates 11, 12 comprises pins 16. The pins 16 may be fitted to the plate 11, 12 or may be formed integral with the plate 11, 12 during its machining. These pins 16 are configured to engage with orifices 37 in the flanges 31, 32 so as to secure the tool 10 in a circumferential direction to the body 30 of the casing. According to an embodiment not shown in the figures, the pins 16 may be formed by the ends of the rods 13, 14 which pass through the plates 11, 12 and may be inserted into the orifices 37 of the flanges 31, 32. These pre-existing orifices 37 are advantageously those intended to receive the screws for attaching the impeller 2 to another stator element of the turbine engine. The present disclosure uses some of these orifices 37 to temporarily connect the tool 10 onto the flanges of the casing 3.
The tool 10 of the disclosure may be made of a metal alloy, such as steel.
The steps of the manufacturing method according to the disclosure are described with reference to
To carry out the steps of the manufacturing method of the disclosure, the present disclosure uses a casing 3, shaping tools 10 according to the disclosure, an autoclave 9 and a pressurization system 19.
In practice, during the bonding operation, the casing 3 is placed into the autoclave 9 so that its axis A is oriented vertically. The system 19 is mounted inside the casing 3, the system 19 being schematically shown in
Thus, a first step a) of the method of the disclosure consists in mounting the tools 10 on the external circumferential surface of the body 30 of the casing 3, between the flanges 31, 32. For this purpose, at least two tools 10 are evenly distributed in circumferential areas Z outside the body 30 (visible in
The first plate 11 of each tool 10 is applied against a radial face of the flange 31 and the second plate 12 is applied against a radial face facing the other flange 32. For this purpose, each tool 10 is manipulated by an operator so as to increase the length of the rods 13, 14 in order to exert the necessary bearing forces on the flanges 31, 32, as described in the foregoing. The lengths of the rods 13, 14 can be adjusted by means of the manual system with knob adjuster 150 and/or slide.
In order to guarantee a precise positioning of the tools 10 on the casing 3, it is also possible to align the pre-existing orifices 37 of the flanges 31, 32 with the pins 16 of the tools 10.
Finally, pins 16 of the plates 11, 12 are engaged in the orifices 37 of the flanges 31, 32, so as to lock, at least temporarily, the tools assembly to the casing.
In a particular example of implementation of the disclosure, the assembly of tools 10 equipped on the casing 3, has a total weight of between 8 and 15 kg.
A second step b) of the method of the disclosure consists in bonding the abradable layer 4 to the internal surface 34 of the intermediate section 33 of the casing 3. During this step b), the casing 3 is placed into the autoclave 9 and a portion of the system 19 is installed inside the casing (
At the end of this step b), the temperature and the pressure to which the casing 3 is subjected are lowered. After the casing 3 has cooled down completely, the abradable layer 4 is bonded and attached to the internal surface 34, and the tools 10 can be dismantled and removed.
The disclosure brings advantages on several levels. From a technical point of view, there is no longer any need to carry out integration studies depending on the state of deformation of the flanges of the casing to match its final nominal operating state in a turbine engine. From an industrial point of view, there is no longer any need for custom machining of the faces of the flanges or for reworking in the event of excessive deformation. The manufacture and the assembly of the casing is simplified, as is its three-dimensional control.
The disclosure thus allows to improve the mechanical and aerodynamic performance of the casing, as well as its manufacturing method and to gain in overall cycle time.
Number | Date | Country | Kind |
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1907058 | Jun 2019 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/FR2020/051114 | 6/26/2020 | WO |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2020/260835 | 12/30/2020 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
10759122 | Mathon et al. | Sep 2020 | B2 |
20030082024 | Scott | May 2003 | A1 |
20090277153 | Harper | Nov 2009 | A1 |
20140294574 | Charles | Oct 2014 | A1 |
Number | Date | Country |
---|---|---|
103836002 | Jun 2014 | CN |
104438462 | Mar 2015 | CN |
108194469 | Jun 2018 | CN |
2116695 | Nov 2009 | EP |
3060438 | Jun 2018 | FR |
Entry |
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International Search Report mailed Oct. 2, 2020, issued in corresponding International Application No. PCT/FR2020/051114, filed Jun. 26, 2020, 2 pages. |
Written Opinion of the International Searching Authority mailed Oct. 2, 2020, issued in corresponding International Application No. PCT/FR2020/051114, filed Jun. 26, 2020, 6 pages. |
English translation of Written Opinion mailed Oct. 2, 2020, issued in corresponding International Application No. PCT/FR2020/051114, filed Jun. 26, 2020, 6 pages. |
International Preliminary Report on Patentability mailed Dec. 28, 2021, issued in corresponding International Application No. PCT/FR2020/051114, filed Jun. 26, 2020, 7 pages. |
First Chinese Office Action mailed Nov. 7, 2023, issued in corresponding Chinese Patent Application No. 202080050925.0, filed Jun. 26, 2020, 4 pages. |
Number | Date | Country | |
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20220268175 A1 | Aug 2022 | US |