Adjustable compaction wedge to compensate for mold wear

Abstract

Adjustable compacting wedge to compensate for mold wear Mold (300) for manufacturing a gas turbine revolution part comprising: - a mandrel (331) on which a fiber preform (310) is intended to be wound comprising an annular wall, the profile of an external surface of which corresponds to that of an internal surface of the part and two lateral flanges (330) the profiles of which correspond to those of radial edges of the part;- a plurality of angular counter-mold sectors (321) intended to be assembled on the mandrel, to close the mold and to compact a fiber preform wound on the mandrel, and - at least two compacting wedges (320) intended to be placed in abutment on fiber preform parts intended to form the radial edges (311) of the part between the fiber preform wound on the mandrel and at least one angular counter-mold sector (321), characterized in that the compacting wedges comprise two separate portions (321, 322) assembled together by screws (323, 324) to adjust their abutment on the fiber preform parts intended to form the radial edges. Figure for the abstract: Fig. 3;

Description

Title of the invention: Adjustable compacting wedge to compensate for mold wear Technical field

[0001] The present invention relates to the general field of the manufacture of rotating parts used in turbomachines, such as in particular gas turbine fan casings or turbomachine casings for aeronautical engines. Prior art

[0002] A gas turbine or turbomachine aircraft engine comprises rotating parts such as a fan casing. This fulfills several functions. It defines the air inlet stream into the engine, supports an abradable material opposite the tip of the fan blades, supports a possible sound wave absorption structure for acoustic treatment at the engine inlet and incorporates or supports a retention shield. The latter constitutes a trap retaining debris, such as ingested objects or fragments of damaged blades, projected by centrifugation, in order to prevent them from passing through the casing and reaching other parts of the aircraft.

[0003] The production of a fan casing made of composite material has already been proposed. For example, reference may be made to patent EP 1 961 923 which describes the manufacture of a casing made of composite material with varying thickness comprising the formation of a fiber preform by superimposed layers of a fiber texture and the densification of the fiber reinforcement by a matrix. More specifically, this document provides for the use of a take-up mandrel for the three-dimensional weaving of the fiber texture, the latter then being wound in superimposed layers on an impregnation mandrel having an outer surface whose profile corresponds to that of the central part of the casing to be manufactured and two lateral flanges corresponding to fixing flanges of the casing. The fiber preform is held on the impregnation mandrel and resin impregnation is carried out before polymerization.

[0004] To carry out the impregnation of the fiber preform by an RTM (“Resin Transfer Molding”) type injection process, it is known to position the elements of a counter-mold on the impregnation mandrel and thus form an injection mold. For example, reference may be made to application WO 2013 / 060978 which discloses the installation of angular sectors to close the resin injection mold on the impregnation mandrel. When closing the injection mold, compacting wedges may be used to maintain the compaction force on the preform. These wedges are used in particular to compact the end flanges of the preform which are vertical (or radial) and therefore have a different compaction direction from the rest of the preform which has a radial compaction direction. These shims also make it possible to prevent that by directly placing sectors with a radial closing direction, these same sectors do not bend the flanges or cause them to buckle or shear. Thus, the counter-mold is formed from the compaction shims and the angular sectors.

[0005] The compacting wedges are, in the closed position, in contact with the angular sectors of the counter-mold and the fiber preform, in particular at the level of the future fixing flanges of the casing. Given that the axial positioning of the angular sectors has a certain variability and that an additional variability is added by the junction between the wedge and the sectors, the final variability of the positioning of the wedge is very important. This directly influences the final thickness of the part to be manufactured in this area. In addition, this is an area in which we seek to have good control of the thicknesses because the flanges are then machined. This control is also important to control the volume rate of fibers according to the quantity of injected resin. However, after several uses, the angular sectors of the counter-mold wear out and can become shorter.Thus, when positioning the compacting wedges and angular sectors against the fiber preform, the compacting force exerted between the fiber preform and the compacting wedges is reduced, which results in a greater quantity of resin in the preform after injection. This excess resin and the low volume rate of fibers can create non-conformity at the flanges, and it therefore becomes necessary to change the mold to avoid this non-conformity.

[0006] It is therefore desirable to have an injection mold, in particular new compacting shims making it possible to adapt to the wear of the angular sectors of the counter-mold in order to reduce the variability of the thickness of the preform at the radial edges of the part to be manufactured and thus avoid changing the mold. Statement of the invention

[0007] The invention relates to a mold intended to be used for the manufacture of a gas turbine revolution part made of composite material comprising: - a mandrel on which a fibrous preform is intended to be wound, comprising an annular wall, the profile of an external surface of which corresponds to that of an internal surface of the part to be manufactured, and two lateral flanges, the profiles of which correspond to those of the radial edges of the part to be manufactured; - a plurality of angular counter-mold sectors intended to be assembled in a sealed manner on the mandrel and intended to close the mold and to compact a fibrous preform wound on the mandrel, and - at least two compacting wedges, the wedges being intended to be placed in support on the parts of the fiber preform intended to form the radial edges of the part to be manufactured between the fiber preform wound on the mandrel and at least one angular sector of the counter-mold,

[0008] characterized in that at least one of the compacting wedges comprises two separate portions assembled together by screws so as to adjust their support on the external flanges of the casing to be manufactured.

[0009] The screws assembling the two portions of the compacting wedges make it possible to lengthen the compacting wedges to compensate for their wear. This therefore makes it possible to reduce non-conformities by ensuring constant support and compaction of the preform parts intended to form the radial edges of the revolution part to be manufactured as they are used.

[0010] Thus, the mold according to the invention is remarkable in that it makes it possible to compensate for the wear of the compacting shims and the angular sectors of the counter-mold, thus making it possible to avoid changing the mold.

[0011] The invention is also remarkable in that it allows the service life of the molds to be extended by compensating for mold wear by adjusting the compacting shims.

[0012] According to a particular characteristic of the invention, the mold comprises at least one sealing joint placed between the two portions of one of the compacting wedges.

[0013] The seal between the two portions of the compacting wedges prevents the resin injected into the mold from seeping between the two portions. The screws joining the two portions also allow the seal to be crushed.

[0014] According to another particular characteristic of the invention, the mold also comprises injection ports configured to inject a resin into the mold, the injection ports being placed on the angular counter-mold sectors facing the annular wall of the mandrel, or on the annular wall of the mandrel facing the angular counter-mold sectors or on the lateral flanges of the mandrel facing the compacting wedges.

[0015] The injection ports allow the resin to be injected into the mold and into the fiber preform to form a matrix in the fiber preform.

[0016] Another object of the invention is a method for closing an injection mold intended to be used for the manufacture of a gas turbine revolution part made of composite material, the mold comprising a mandrel on which a fiber preform is intended to be wound, the mandrel comprising an annular wall whose profile of the outer surface corresponds to that of the inner surface of the part to be manufactured and two lateral flanges whose profiles correspond to those of edges radials of the part to be manufactured, the mold also comprising a plurality of angular counter-mold sectors intended to close the mold and to compact the fiber preform wound on the mandrel and at least two compacting wedges which each comprise two distinct portions, the method comprising: - the watertight assembly of the angular counter-mold sectors on the mandrel; and - the placement of the two portions of the compacting wedges on the side plates, the assembly of the two portions of the compacting wedges by at least one screw and the adjustment of the screws so that the two portions of the compacting wedges are supported on the parts of the fiber preform intended to form the radial edges to be manufactured.

[0017] Yet another object of the invention is a method of manufacturing a gas turbine revolution part made of composite material comprising: - winding a fiber preform onto the mandrel of a mold according to the invention; - closing the mold according to the closing method of the invention; - injection of a resin into the mold; and - the demolding of the revolution part.

[0018] Yet another object of the invention is a gas turbine comprising a fan casing manufactured by a method according to the invention. Brief description of the drawings

[0019] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate exemplary embodiments thereof which are not limiting in nature.

[0020] [Fig.l] [Fig.l] schematically and partially represents a gas turbine fan casing.

[0021] [Fig.2A] [Fig.2A] schematically and partially represents a section of a mold according to the prior art, when it is closed and comes out of production.

[0022] [Fig.2B] [Fig.2B] represents a perspective view of the mold of [Fig.2A].

[0023] [Fig.2C] [Fig.2C] represents, in a very schematic and partial manner, a section of a mold according to the prior art, when it is closed after several uses.

[0024] [Fig.3] [Fig.3] schematically and partially represents a section of a mold according to an embodiment of the invention when it is closed.

[0025] [Fig.4] [Fig.4] schematically and partially represents a section of a mold according to another embodiment of the invention when it is closed. Description of the embodiments

[0026] The invention applies to the manufacture of a gas turbine revolution part in composite material comprising an annular wall or barrel and radial edges extending on each side of the annular wall. The gas turbine may in particular be a turbomachine.

[0027] The invention will be described below in the context of its application to the manufacture of a fan casing for an aeronautical gas turbine engine.

[0028] [Fig.l] represents a perspective view of a fan casing 10 which can be manufactured using a mold and a method according to the invention. Such a casing is centered on a longitudinal axis XX and comprises an annular wall or barrel 11 delimited upstream by a first radial edge, here an upstream flange 12, and downstream by a second radial edge, here a downstream flange 13 (upstream and downstream being defined relative to the direction of flow of the air flow in the gas turbine or the turbomachine). The internal surface 14 of the annular wall 11 is intended to delimit the air inlet vein in the gas turbine.

[0029] Figures 2A, 2B and 2C schematically and partially represent a mold 200 according to the prior art, when it is closed. Figures 2A and 2C are sectional views of the mold 200 and [Fig.2B] a perspective view of the mold 200. More specifically, [Fig.2A] represents the mold 200 leaving production and [Fig.2C] the mold 200 after several uses.

[0030] The mold 200 can be used for impregnation by a process of the RTM type (“Resin Transfer Molding”) of a fiber preform 210 in order to manufacture a fan casing 10 such as that shown in [Fig.l]. The fiber preform 210 used to manufacture the fan casing 10 can comprise carbon, glass, aramid or ceramic fibers. It can be made by stacking layers or plies obtained by two-dimensional weaving. It can also be made directly in a single piece by three-dimensional weaving. By two-dimensional weaving, here is meant a conventional weaving method by which each weft thread passes from one side to the other of the threads of a single warp layer or vice versa. By three-dimensional weaving, here is meant a weaving by which warp threads pass through several layers of weft threads, or weft threads pass through several layers of warp threads.

[0031] The fiber preform 210 can also be made from unidirectional fiber sheets, which can be obtained by automatic fiber placement, or by filament winding.

[0032] The impregnation matrix of the fibrous preform 210 may be made of polymer, for example epoxide, bismaleimide or polyimide.

[0033] The mold 200 is rotatably mounted on a drive axis (not shown) centered on the axis XX, and comprises a mandrel 231. The mandrel 231 comprises an annular wall taking the form of a barrel on which a fiber preform 210 is intended to be wound, and two lateral flanges (only one flange 230 is shown). The mandrel 231 is held on its drive axis by means of spokes not shown.

[0034] The lateral flanges 230 form a support intended to receive the folded parts 211 of the preform 210 wound on the mandrel 231, and which are intended to form the upstream 12 and downstream 13 flanges of the fan casing 10.

[0035] The mold 200 also comprises a counter-mold composed of a plurality of angular sectors 221 assembled in a sealed manner on the mandrel 231, and two compacting wedges 220. In FIGS. 2A and 2C, only one angular sector 221 with its compacting wedge 220 are shown.

[0036] When the mold 200 leaves production, the compacting wedge 220 is pressed on the folded part 211 of the fiber preform 210 and the angular sector 221 is pressed on the compacting wedge 220 ([Fig.2A]).

[0037] After several uses, the angular sectors 221 of the mold 200 wear out and their length may vary, in particular decrease. A space 250 (shown in an exaggerated manner in [Fig.2C]) thus appears between the flange 211 of the fiber preform 210 and the compacting wedge 220. This space 250 may fill with resin during the injection of resin into the mold 200 and create non-conformities in the thickness of the flange formed by the folded-down portion 211 of the preform 210 (because the latter will have an excess thickness due to expansion of the preform at this location or due to the presence of resin). In order to avoid non-conformity, as soon as the molds 200 of the prior art are worn, they are sent for repair and / or replaced by a new mold.

[0038] [Fig. 3] represents, schematically and partially, a sectional view of a mold 300 according to an embodiment of the invention, when it is closed.

[0039] Like the mold 200 of the prior art, the mold 300 according to the invention can be used for impregnation by a process of the RTM type (“Resin Transfer Molding”) of a fiber preform 310 in order to manufacture a fan casing 10 such as that presented in [Fig.l].

[0040] The mold 300 is rotatably mounted on a drive axis (not shown) centered on the axis XX, and comprises a mandrel 331. The mandrel 331 comprises an annular wall taking the form of a barrel on which a fiber preform 310 is intended to be wound, and two lateral flanges (only one flange 330 is shown). The mandrel 331 is held on its drive axis by means of spokes not shown.

[0041] The lateral flanges 330 form a support intended to receive the folded parts 311 of the preform 310 wound on the mandrel 331, and which are intended to form the upstream 12 and downstream 13 flanges of the fan casing 10.

[0042] The mold 300 also comprises a counter-mold composed of a plurality of angular sectors 351 assembled in a sealed manner on the mandrel 331, and at least two compacting wedges 320 placed between the folded parts 311 of the fiber preform 310 and the angular sectors 351, a single compacting wedge 320 being shown in [Fig.3].

[0043] Unlike the prior art, the compacting wedge 320 is formed of two separate portions 321 and 322 assembled by screws 323 and 324. The screws 323 and 324 make it possible to assemble the two portions 321 and 322 and also to adjust the dimensions of the compacting wedge 320. Indeed, by reducing or increasing the tightening of the two portions 321, 322, the length of the wedge 320 can be varied. Thus, by reducing the tightening of the screws 323 and 324, the compacting wedge 320 can be lengthened to compensate for its wear over time, and readjust the support of the compacting wedge 320 on the folded part 311 (which will form one of the flanges of the casing) of the preform 310 to prevent resin from infiltrates between the folded part 311 and the wedge 320.

[0044] [Fig. 4] represents, schematically and partially, a sectional view of a mold 400 according to another embodiment of the invention, when it is closed.

[0045] Like the mold 200 of the prior art and the mold 300, the mold 400 can be used for impregnation by a process of the RTM type (“Resin Transfer Molding”) of a fiber preform 410 in order to manufacture a fan casing 10 such as that presented in [Fig.l],

[0046] The mold 400 is rotatably mounted on a drive axis (not shown) centered on the axis XX, and comprises a mandrel 431. The mandrel 431 comprises an annular wall taking the form of a barrel on which a fiber preform 410 is intended to be wound, and two lateral flanges (only one flange 430 is shown). The mandrel 431 is held on its drive axis by means of spokes not shown.

[0047] The lateral flanges 430 form a support intended to receive the folded parts 411 of the preform 410 wound on the mandrel 431, and which are intended to form the upstream 12 and downstream 13 flanges of the fan casing 10.

[0048] The mold 400 also comprises a counter-mold composed of a plurality of angular sectors 451 assembled in a sealed manner on the mandrel 431, and at least two compacting wedges 420 placed between the folded parts 411 of the fiber preform 410 and the angular sectors 451, a single compacting wedge 420 being shown in [Fig.4].

[0049] As indicated with reference to [Fig. 3], the compacting wedge 420 comprises two separate portions 421 and 422 assembled by screws 423 and 424. These screws 423, 424 make it possible to vary the length of the compacting wedge 420 in order to be able to compensate for the wear of the angular sector 451, and in particular its shortening by loosening the screws 423 and 424.

[0050] The mold 400 also comprises a seal 440 placed between the two portions 421 and 422 of the compacting wedge 420. This seal 440 is held in place by tightening the screws 423 and 424 and prevents resin from infiltrating between the two portions 421 and 422 of the compacting wedge 420. In addition, in order to withstand the heating temperatures in the mold 400 allowing the matrix to be formed in the fiber preform 410, the seal 440 can withstand temperatures between 100°C and 160°C, for example a temperature of 150°C.

[0051] The mold 400 also comprises injection ports 461, 462 for injecting a resin into the mold 400. The injection ports 461, 462 may be placed on the annular wall of the mandrel 431 opposite the fiber preform 410 and the angular sector 451 of the counter-mold (case of the injection port 461), and / or on a lateral flange 430 of the mandrel 431 opposite the folded portion 411 of the fiber preform 410 and the compacting wedge 420 (case of the injection port 462). The injection ports may also be placed on an angular sector 451 of the counter-mold opposite the fiber preform 410 and the annular wall of the mandrel 431.

[0052] Whatever the embodiment, the two portions of the compacting wedge are of any complementary shape to each other and of any complementary shape to the folded part of the fiber preform and the angular sector of the counter-mold.

[0053] The manufacture of a fan casing 10 using a mold according to the invention is now described.

[0054] A fiber preform is first wound onto the mandrel 331, 431 of a mold 300, 400 according to the invention. Methods have already been proposed for winding a fiber preform produced for example by three-dimensional weaving around a mandrel 331, 431 such as that of the invention, and will not be described in more detail. Reference may, for example, be made to application WO 2012 / 140355 which proposes a machine for winding a fiber texture onto an impregnation mandrel.

[0055] Once the preform is wound onto the mandrel, the mold must be closed to compact the preform. To do this, the angular sectors are assembled on the mandrel in a sealed manner and the two portions of the compacting wedges are placed on the side plates of the mandrel so as to rest on the future flanges of the casing being manufactured. The compacting wedges are also positioned against a longitudinal face of an angular sector. Then the two portions of the compacting wedges are assembled in a sealed manner by screws and the tightening of the screws is adjusted so that the compacting wedges remain in contact with the future flanges of the casing while remaining positioned on the longitudinal face of the corresponding angular sector. A seal can be placed between the two portions of the compacting wedge before their assembly and tightening so as to guarantee the watertight assembly of the two portions.

[0056] The compacting wedges thus allow compaction in a direction substantially perpendicular to the preform and therefore make it possible to avoid creases and buckling of the fiber preform.

[0057] A polymerizable resin is then injected into the mold by a pressure differential (by an RTM type process), and the latter is polymerized (by heating or cooling for example, depending on the nature of the resin used). The fan casing thus produced can then be demolded.

[0058] According to one embodiment, the mold of the invention may comprise only one adjustable compacting wedge, that is to say have a wedge comprising two distinct portions assembled together by screws, the other compacting wedge being fixed. In this case, the wear of the wedges is compensated by the adjustable wedge so as to adjust their support on the preform parts intended to form the radial edges of the part of revolution to be manufactured.

[0059] Furthermore, the mold of the invention may comprise a mandrel having on its external surface a variable profile or several profiles making it possible to form a part of revolution having an internal and / or external surface of variable shape.

Claims

Claims

1. Mold (300, 400) intended to be used for the manufacture of a gas turbine revolution part (10) made of composite material comprising: - a mandrel (331, 431) on which is intended to be wound a fiber preform (310, 410) comprising an annular wall of which an outer surface profile corresponds to that of an inner surface (14) of the revolution part (10) to be manufactured and two lateral flanges (330, 430) of which the profiles correspond to those of radial edges (12, 13) of the revolution part (10) to be manufactured;- a plurality of angular counter-mold sectors (351, 451) intended to be assembled in a sealed manner on the mandrel and intended to close the mold and to compact the fiber preform wound on the mandrel, and - at least two compacting wedges (320, 420), the wedges being intended to be placed in abutment on the parts of the fiber preform intended to form the radial edges (311, 411) of the part of revolution (10) to be manufactured between the fiber preform wound on the mandrel and at least one angular counter-mold sector (351, 451), characterized in that at least one of the compacting wedges comprises two distinct portions (321, 322, 421, 422) assembled together by screws (323, 324, 423, 424) so ​​as to adjust their support on the external flanges of the housing to be manufactured.;

2. Mold (400) according to claim 1, comprising at least one sealing gasket (440) placed between the two portions (421, 422) of one of the compacting wedges (420).

3. Mold (400) according to any one of claims 1 or 2, also comprising injection ports (461, 462) configured to inject a resin into the mold, the injection ports being placed on the angular counter-mold sectors facing the annular wall of the mandrel, or on the annular wall of the mandrel facing the angular counter-mold sectors or on the lateral flanges of the mandrel facing the compacting wedges.

4. A method of closing an injection mold for use in the manufacture of a gas turbine revolution part made of composite material, the mold comprising a mandrel on which a fiber preform is intended to be wound, the mandrel comprising an annular wall whose profile of the outer surface corresponds to that of the inner surface of the part to be manufactured and two lateral flanges whose profiles correspond to those of radial edges of the part to be manufactured, the mold also comprising a plurality of angular counter-mold sectors intended to close the mold and to compact the fiber preform wound on the mandrel and at least two compacting wedges which each comprise two separate portions, the method comprising: - the sealed assembly of the angular counter-mold sectors on the mandrel;and - the placement of the two portions of the compacting wedges on the side plates, the assembly of the two portions of the compacting wedges by at least one screw and the adjustment of the screws so that the two portions of the compacting wedges are supported on the parts of the fiber preform intended to form the radial edges of the part to be manufactured.;

5. A method of manufacturing a gas turbine revolution part made of composite material comprising: - winding a fiber preform onto the mandrel of a mold according to any one of claims 1 to 3; - closing the mold according to the method of claim 4; - injecting a resin into the mold; and - demolding the revolution part.

6. A gas turbine comprising a fan casing (10) manufactured by a method according to claim 5.

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