Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
  • B23P15/04—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass turbine or like blades from several pieces
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/14—Form or construction
  • F01D5/147—Construction, i.e. structural features, e.g. of weight-saving hollow blades
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
  • F01D5/282—Selecting composite materials, e.g. blades with reinforcing filaments
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
  • F01D5/288—Protective coatings for blades
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/02—Selection of particular materials
  • F04D29/023—Selection of particular materials especially adapted for elastic fluid pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/26—Rotors specially for elastic fluids
  • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
  • F04D29/321—Rotors specially for elastic fluids for axial flow pumps for axial flow compressors
  • F04D29/324—Blades
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2220/00—Application
  • F05D2220/30—Application in turbines
  • F05D2220/36—Application in turbines specially adapted for the fan of turbofan engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2230/00—Manufacture
  • F05D2230/10—Manufacture by removing material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2230/00—Manufacture
  • F05D2230/10—Manufacture by removing material
  • F05D2230/14—Micromachining
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2230/00—Manufacture
  • F05D2230/20—Manufacture essentially without removing material
  • F05D2230/23—Manufacture essentially without removing material by permanently joining parts together
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2230/00—Manufacture
  • F05D2230/20—Manufacture essentially without removing material
  • F05D2230/23—Manufacture essentially without removing material by permanently joining parts together
  • F05D2230/232—Manufacture essentially without removing material by permanently joining parts together by welding
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2230/00—Manufacture
  • F05D2230/50—Building or constructing in particular ways
  • F05D2230/53—Building or constructing in particular ways by integrally manufacturing a component, e.g. by milling from a billet or one piece construction
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2240/00—Components
  • F05D2240/20—Rotors
  • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
  • F05D2240/303—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the leading edge of a rotor blade
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/10—Metals, alloys or intermetallic compounds
  • F05D2300/17—Alloys
  • F05D2300/171—Steel alloys
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/10—Metals, alloys or intermetallic compounds
  • F05D2300/17—Alloys
  • F05D2300/174—Titanium alloys, e.g. TiAl

Definitions

• the present invention relates to the technical field of turbomachinery and more particularly that of fan blades of composite material.
• the invention relates more particularly to a metal reinforcement of a turbine engine blade made of composite material, as well as to a method of producing such a reinforcement.
• this metal reinforcement can be produced entirely by milling, from a block of metallic material, for example a block of titanium.
• a blade has a complex shape, in particular having a double camber, so that this reinforcement requires multiple recovery operations and complex tools. This induces significant manufacturing costs.
• the document FR 3 009 982 proposes a process for forging a reinforcement using specific tools to conform each of the lateral fins of the reinforcement.
• a forging process can cause folds at the fins during twisting, which are primarily caused by the thin thickness of the fins.
• the movements of each point of the part in formation are not made in a plane, but in three dimensions.
• the tool will first touch certain parts of the part before others because the part is strongly left. The efforts are therefore different according to the zones, which can also create folds.
• Document US 201 1/0274551 describes another method which also uses a forging step to arch a plate of metallic material and a machining step to make a slit in the thickness of the plate. This process also includes a step of superplastic forming in a mold, by introducing a hot gas inside the plate.
• the superplastic forming step does not allow precise control of the internal surface of the reinforcement and in particular its bottom radius, which is however essential to allow the introduction and maintenance of the composite blade in the reinforcement. .
• the superplastic forming step has the same drawbacks as a forging process. Indeed, the control and retouching of the interior of the part are complicated to carry out, while the shaping can cause folds.
• the part being relatively flexible, it is necessary to provide complex tools to hold it firmly without deforming it during its machining.
• the object of the invention is to overcome these drawbacks by proposing a method for producing a metal reinforcement of the leading edge of a turbine engine blade, making it possible to simplify the manufacturing range, to reduce the costs of manufacturing this reinforcement, retaining sufficient mechanical strength characteristics.
• the invention thus relates to a method for producing a metal reinforcement of a turbine engine blade comprising an aerodynamic surface which extends between a leading edge and a trailing edge, said reinforcement comprising a base forming its leading edge and being extended by two lateral fins so as to define an internal surface capable of receiving the leading edge of the blade, the method comprising the following steps:
• the invention deviates completely from conventional methods leading to the production of a one-piece metal reinforcement.
• the invention also departs from the methods which envisage making a reinforcement in several parts which are assembled by a diffusion welding technique.
• diffusion welding techniques almost do not reduce the properties of the material of the parts at the assembly level unlike fusion welding techniques (welding in English terminology) or mixing friction (friction stir welding in English terminology) which are nevertheless retained within the framework of the invention.
• the location of the assembly will be chosen according to the distribution of the stresses to which the reinforcement is subjected, this distribution being known during the design of the part.
• the invention thus makes it possible to position the assembly in the most appropriate zone so that the reinforcement has sufficient mechanical strength.
• this process eliminates any forging or forming step during the shaping of the reinforcement from a crude.
• the fact remains that the crude oil on which the process can be applied can be a crude oil previously forged to optimize the material used.
• the fins are entirely produced by machining (to define the inside and the outside of the fins) and in the same operation.
• the machining of the fin is carried out without any other operation interposed between two stages of machining of this fin, which can be offset in time.
• the method does not carry out any viscoplastic deformation operation of the material, for example by forming or forging, aimed at modifying the shape of the part as a whole.
• the machining is not followed by any operation aiming to modify the section or the thickness of the fins, except possibly in the area of assembly of the parts.
• the thickness of the fins as well as their shape are therefore perfectly controlled.
• the internal radius of the reinforcement is also produced by machining and it is no longer subjected to other geometric transformations. Its implementation is simple to master, unlike known methods, which reduces the tolerance ranges.
• finished part is understood here a part which is in its final definition in terms of shape and thickness in its internal surface and a large part of its external surface. In other words, only a percentage by mass of between 0 and 5% is capable of being machined on the external surface of the part, after it has been assembled with the other component (s) constituting the reinforcement.
• the method can be implemented by assembling two or three parts.
• step (a) are preferably made a first monobloc piece forming one of the fins of the reinforcement and at least partially the base of the reinforcement and a second monobloc piece forming at least the other fin .
• step (a) are preferably made a first one-piece piece forming one of the fins of the reinforcement, a second one-piece piece forming at least the other fin and a third one-piece piece forming at least partially the base of the reinforcement.
• the method can be implemented with parts which are all produced by machining a metallic crude.
• At least one of the parts is obtained by machining an already existing metal reinforcement.
• step (a) the machining of a metallic crude is carried out alternately on each side of the crude to obtain said fin.
• first and second intermediate parts are obtained, comprising a first part corresponding to a fin and a second part forming a heel.
• step (a) the first intermediate part is positioned on said tool to remove or machine said heel.
• step (a) the heel of the second intermediate part is machined to at least partially form the rounded internal surface of the base and the second intermediate part is then positioned on said tool to machine the external surface of said heel and form at least partially the outer surface of the base.
• step (b) a step of texturing the internal surface of at least one of the parts is carried out, to give it a surface condition facilitating the subsequent fixing of the blade and of the reinforcement.
• step (b) the assembly between the two parts is located to the right of the rounded internal surface of the base.
• the invention also relates to a metal reinforcement of a turbine engine blade made of composite material comprising an aerodynamic surface which extends between a leading edge and a trailing edge, said reinforcement comprising a base forming its leading edge and being extended. by two lateral fins, said reinforcement defining an internal surface capable of receiving the leading edge of the blade and comprising at least two parts each forming at least one of the fins of the reinforcement and being assembled by a fusion welding technique or by friction mixing, each piece being one piece and finished.
• a weld relief is present on the internal surface of the reinforcement, projecting relative to this surface,
• the assembly between the first part and the second part is located at the right of the rounded internal surface of the base
• the reinforcement is made of steel or a titanium alloy.
• the invention also relates to a turbine engine blade made of a composite or metallic material, of the aluminum, magnesium or even graphene type and comprising a reinforcement according to the invention.
• this blade has a recess of complementary shape to the weld relief present on the internal surface of the reinforcement.
• Figure 1 is a side view of a blade having a metal reinforcement of the leading edge.
• FIG. 2 is a perspective view of the leading edge illustrated in FIG. 1.
• Figure 3 includes Figures 3A to 3F which are side views illustrating the stages of manufacturing a first component part of a reinforcement according to the invention.
• FIG. 4 comprises the figs 4A to 4G which are side views illustrating the stages of manufacture of the second component part of the reinforcement according to the invention.
• Figure 5 includes Figures 5A to 5C which are sectional views illustrating the assembly steps of the two component parts of the reinforcement according to the invention.
• Figure 6 includes Figures 6A to 6E which are sectional views illustrating alternative embodiments of the reinforcement according to the invention.
• Figure 7 is a perspective view illustrating another alternative embodiment of the reinforcement according to the invention.
• Figure 8 includes Figures 8A and 8C which are sectional views illustrating the section of the reinforcement according to Figure 7 according to three different section planes.
• Figure 1 illustrates a blade 1, in particular made of a composite material, for example an assembly of carbon fibers which is molded with resin by a vacuum injection process.
• This blade comprises an aerodynamic surface 10 extending in a first axial direction 11 between a leading edge 13 and a trailing edge 14 and, in a second radial direction 12, between a base 15 and a top 16.
• This aerodynamic surface 10 therefore has two lateral faces connecting the leading edge 13 to the trailing edge 14, one of them forming the upper surface of the blade and the other the lower surface of the blade.
• Figure 1 only the underside 17 of the blade is shown.
• This blade 1 comprises a metal reinforcement 2 'which is fixed to the blade, in particular by gluing so as to cover the leading edge 13.
• This reinforcement 2 ' extends in the first axial direction 11, from the leading edge 13 of the blade as far as a part of the lower surface and the upper surface. It also extends in the second radial direction 12, between the base 15 and the apex 16 of the blade 1.
• the reinforcement 2 ’ is therefore designed to conform to the shape of the leading edge 13 of the blade. Given the shape of the blade, the reinforcement 2 ’therefore has a double camber, as illustrated in FIG. 2.
• the reinforcement 2 has a substantially V-shaped section and has a base 21 'forming the leading edge 20' of the reinforcement which is extended by two lateral wings 22 'and 23', the wing 23 'being intended to cover the upper surface of the blade, while the fin 22 'is intended to cover the lower surface of the blade.
• the two fins have the same length, but this is not always the case.
• the internal surface 200 ’of the reinforcement is defined inside the V and it is capable of receiving the leading edge 13 of the blade 1.
• Figure 2 shows that the base 21 'has a rounded internal surface 210'.
• Reinforcement 2 is made of metal. We choose a metal with a significant capacity for absorbing energy due to shocks. This reinforcement is conventionally made of a titanium alloy or steel.
• the reinforcement 2 ’ can be bonded to the blade 1 by means of known adhesives, such as, for example, a cyanoacrylic adhesive or an epoxy adhesive. Other means of fixing the reinforcement to the blade can be provided. They are chosen according to the materials of the blade and the reinforcement.
• FIG. 3 describes the steps for manufacturing a first piece of the reinforcement which is here the upper surface part of the reinforcement, that is to say the part comprising the fin intended to match the upper surface of the blade.
• FIG. 4 describes the steps for producing the second part of the reinforcement which is here the lower surface part, that is to say the part comprising the lower surface fin intended to match the lower surface of the blade.
• the invention is not limited to this mode of implementation of the method and the steps described with reference to FIG. 3 could be used to make the lower surface part, while the steps illustrated in FIG. 4 could be used to make the upper surface part.
• FIG. 3A illustrates a metallic crude 3 in which the first part of the reinforcement will be produced.
• This crude 3 is a forged or rolled crude for example.
• This forging step is not necessary for the implementation of the process.
• the rough has a thickness much greater than that of the fin, the first part being machined then remains rigid.
• FIGS. 3B and 3C illustrate the machining operations (for example by milling or rectification) carried out with the cutter 6 alternately on each face 30, 31 of the stock 3 which are opposite.
• the cutter 6 can alternately machine each face over a thickness of 10 mm.
• the clamping tool which maintains the stock during machining is not illustrated in the figures. It is positioned on the right side of FIGS. 3A to 3D or also on the side of the heel 42 illustrated in FIG. 3D.
• This machining is carried out from the end of the stock located opposite the clamping tool (or even opposite the heel 42 illustrated in Figure 3D) to this clamping tool.
• the rigidity of the part can remain high, which makes it possible to obtain high machining performance and to guarantee the thicknesses in the part and thus to respect tolerances as well as possible.
• Figure 3D illustrates the intermediate part 4 which is obtained after these machining operations.
• This intermediate part 4 comprises a first part 41 corresponding substantially to the upper wing 23 and a second part 42 forming a heel and corresponding to an end part of the block 3.
• the part 4 undergoes another machining operation to create a face 43 corresponding to the end of the fin 23 which is opposite to the heel 42. This operation can also be carried out during the machining of the rough to get the first part 41.
• a texturing step can be carried out, in order to subsequently facilitate the fixing of the blade on the reinforcement according to the invention.
• the thickness of the first part 41 of this part 4 is controlled, in order to make possible adjustments. As illustrated in FIG. 3D, the thickness of this first part 41 is preferably variable and decreases from the second part 42 towards the face 43. The upper wing will therefore have this same variable thickness.
• FIG. 3E shows the part 4 in position on a tool 8 which will later be used for a welding operation.
• This tool 8 has a tapered shape and its external surface corresponds substantially to the internal surface 200 of the reinforcement 2.
• This tool 8 has two shoulders 80 and 81, the shoulder 80 being located on the upper face 82 of the tool and the shoulder 81 on the lower face 83.
• FIG. 3E shows that the part 4 is wedged against the shoulder 80, thanks to its end 43. Its internal face 410 is therefore in contact with the upper surface 82 of the tool.
• heel 42 helps to manipulate the part 4 when it is placed in position on the tool 8.
• FIG. 3F shows the last step in obtaining the upper wing 23, in which the heel 42 is removed.
• a reference face 230 is produced at the end opposite to the end 43. This reference face 230 will be useful for making the connection between the first part and the second part .
• FIGS. 4A to 4G describe stages in the production of the second part, here the part comprising the underside fin.
• FIG. 4A illustrates a metallic rough 5 in which the second part of the reinforcement 2 will be produced.
• This crude 5 is for example a forged or rolled crude.
• the second part 24 of the reinforcement is drawn in dotted lines, which will be obtained at the end of the manufacturing steps illustrated in FIG. 4.
• This part 24 includes the lower surface fin 22 as well as the base 21 of the reinforcement 2.
• Figures 4B and 4C illustrate the machining operations performed with the cutter 6 alternately on each face 50 and 51 of the stock 5 which are opposite.
• the stock 5 is maintained by a clamping tool which is not illustrated in the figures and which is positioned on the right side of Figures 4A to 4E or also on the heel side 72 illustrated in Figure 4E.
• Machining is also carried out from the end of the stock located opposite the clamping tool (or even opposite the heel 72) to this clamping tool.
• FIG. 4D illustrates the intermediate part 7 which is obtained after these machining operations.
• This intermediate part 7 comprises a first part 71 corresponding substantially to the lower surface fin 22 and a second part 72 forming a heel and corresponding to an end part of the block 5.
• FIG. 4D also illustrates a machining operation carried out with the cutter 6a, in the heel 72, in order to define the rounded internal surface 210 of the base 21 of the reinforcement.
• This surface is easily achieved because the inner part of the heel is easily accessible and allows the use of a milling tool without constraint.
• the radius of curvature of this internal surface 210 is defined as a function of the profile of the blade for which the reinforcement is intended. It will be noted that the blade does not necessarily come into contact with all of this internal surface.
• this internal surface and in particular its curvature must be controlled to avoid areas of concentration of stresses which could weaken the reinforcement and to allow correct positioning of the blade relative to the reinforcement.
• FIG. 4E therefore illustrates the intermediate part 7 which then undergoes another machining operation to create a face 73 corresponding to the end of the fin 22 which is opposite to the heel 72.
• This other machining operation can be carried out at during the machining of crude.
• a texturing step can be carried out, in order to subsequently facilitate the fixing of the blade on the reinforcement according to the invention.
• this texturing can in particular be carried out by a micromachining technique by laser or by sandblasting.
• the thickness of the first part 71 of the part 7 is checked, in order to make any adjustments.
• this first part 71 is preferably variable and decreases from the heel 72 towards the face 73.
• the underside fin will therefore have this same variable thickness.
• FIG. 4F shows the part 7 in position on the tool 8.
• the part 7 is wedged against the shoulder 81, thanks to its end 73.
• FIG. 4G shows the last step of obtaining the second part 24 of the reinforcement, in which the external surface of the heel 72 is machined in order to obtain the base 21 of the reinforcement with its leading edge 20 on its external surface 212.
• a reference face 21 1 is produced at the free end of the base 21 of the reinforcement, opposite the leading edge 20 and facing the underside fin 22.
• This reference face 21 1 will be useful for making the connection between the first part and the second part.
• FIGS. 5A to 5C illustrate how the first part 23 and the second part 24 are assembled.
• these two parts 23 and 24 are finished parts, their shape and their dimensions being substantially unchanged in the reinforcement obtained after assembly.
• FIG. 5A illustrates the step in which these two parts are put in place on the welding tool 8.
• the internal face 410 of the first part 23 is in contact with the upper surface 82 of the tool, while its end 43 bears against the shoulder 80.
• the second part 24 is put in place on the tool 8, by bringing its internal face 710 into contact with the underside face 83 of the tool.
• the second part 24 is wedged against the shoulder 81, thanks to its end 73.
• the reference face 230 of the first part 23 is opposite with the reference surface 21 1 of the second part 24.
• FIG. 5B illustrates the next step in which a weld 90 is produced between the reference faces 230 and 21 1.
• the assembly technique used is a fusion welding technique (welding in English terminology) or friction stir welding (friction stir welding in English terminology) which is adapted in particular to the nature of the materials to be welded. It can be a laser welding technique, of the MIG / MAG or TIG type or even by electron beam for example.
• the energy used is relatively low because the thicknesses involved are also low. Indeed, the welding is carried out between the thicknesses of each fin which are small, in particular between 0.5 and 3 mm.
• fusion welding techniques are generally used for blanks of parts because they cause deformations and require subsequent treatments to loosen the stresses. They are also used for massive parts that are less sensitive to deformation. In mechanized welding, fusion welding techniques are used to obtain parts of simple geometry and imprecise dimensions which therefore require subsequent machining and stress relieving treatment. They are also used for parts of small dimensions (a few cms) whose deformations caused by welding are compatible with the expected tolerances and which are not very tight. These parts therefore do not undergo any subsequent operation and in particular, no machining subsequent to the welding. With regard to friction stir mixing techniques, their use is not widespread and, in general, limited to welds following simple paths and generating relatively large weld zones, imposed by the implementation tools.
• the weld will thus be positioned in an area of the fin close to the nose rather than in the nose of the reinforcement because it has a lower stiffness due to the section ratio.
• these techniques have the advantage of being simple and quick to implement, unlike diffusion joining techniques (bonding in English terminology). This is in particular due to the fact that an assembly by diffusion requires an oven and holding tools compatible with the material to be welded.
• a surface treatment or a heat treatment can be carried out. These treatments are optional.
• a heat treatment it may for example be a stress relaxation treatment or solution treatment, to modify the mechanical properties of the weld. It is also possible to provide a straightening or calibration operation to remedy any minor deformations occurring during welding or a minor removal or addition operation of material to correct any geometric deviations associated with the welding. This operation is a simple finishing operation in particular linked to the welding technique used.
• the sum of the masses of the constituent parts of the reinforcement before assembly is greater than 95% of the mass of the final reinforcement intended to be fixed on the blade and which has therefore possibly undergone one or more finishing operations.
• the reinforcement may locally include extra thicknesses or extra lengths (for example extra lengths making it possible to machine the ends of the part or extra thicknesses making it possible to perform polishing).
• the method according to the invention requires only one tool used in all the steps of the method and which makes it possible to obtain a reinforcement having a precise shape and dimensions, thanks to a common reference system.
• the thicknesses of the fins are obtained by a single machining phase in contrast to known methods and by a strategy that maximizes the rigidity of the part. This allows to obtain the expected dimensions, with optimal reproducibility with regard to the thickness of the fins and the shape of the bottom radius which are key characteristics of the reinforcement.
• tolerances of ⁇ 0.02 mm can be obtained with the method according to the invention with regard to the thicknesses, in particular those of the fins.
• the dimensions of the reinforcements obtained with the process according to the invention have a very low dispersion.
• FIG. 5C illustrates the reinforcement 2 obtained after its removal from the tooling 8.
• the reinforcement is then ready to be fixed on the blade 1, subject to a possible finishing operation as defined above. It has the same shape as the reinforcement 2 'illustrated in FIGS. 1 and 2.
• the assembly by welding is carried out between the upper surface fin 23 and the base 21 of the reinforcement and more precisely in line with the rounded internal surface 210.
• the weld extends substantially at right angles to this internal surface.
• the invention is not however limited to this mode of implementation and the junction between the two parts could be located at another location on the rounded internal surface 210 of the base 21 of the reinforcement which is located at the bottom of the surface. internal 200 of the reinforcement.
• the junction or assembly zone 90 corresponds to the entry of this internal surface 210.
• this junction zone 91 is offset beyond this internal surface 210 while remaining close to the bottom of this surface.
• FIGS. 6B and 6C correspond to two other embodiments of the method according to the invention in which the second part corresponds to the lower surface fin 22 of the reinforcement while the first part 25 comprises the upper surface fin 23 as well as the base 21 of the reinforcement.
• FIG. 6B illustrates the junction zone 92 between the parts 22 and 25 in the example illustrated in FIG. 6B, the junction zone 92 between the parts 22 and 25 is located beyond the internal surface 210 of the base 21, while FIG. 6C illustrates the mode of implementation in which the junction zone 93 is located at the entrance to this internal surface 210 and to the right of the latter (reverse mode of FIG. 5A).
• the intermediate part 4 illustrated in FIG. 3D is intended to form a fin, while the intermediate part 7 is intended to form the other fin and the base reinforcement.
• each intermediate piece can be intended to form a fin and part of the base of the reinforcement, the two parts then being complementary.
• the reinforcement is obtained from two parts obtained by machining a crude.
• the invention is not however limited to this mode of implementation and the reinforcement can also be obtained from three pieces for example, each obtained by machining a crude.
• a first part can form a fin, a second part the other fin and a third part the base of the reinforcement.
• the reinforcement can be obtained from an already existing but defective reinforcement.
• at least one component part of the reinforcement is obtained by machining this existing reinforcement while at least one other component part is obtained by machining a crude. The assembly of the parts thus makes it possible to repair the defective reinforcement.
• FIGS. 6D and 6E show that the first part 26 comprises the upper surface fin 23 and a first part 21 a from the base 21 of the reinforcement while the second part 27 comprises the lower surface fin 22 and a second part 21 b of base 21, complementary to the first part 21 a.
• the line of the junction zone 94 extends from the bottom of the surface 210 at an angle to the external surface 212 of the base 21, while in the example illustrated in FIG. 6E, the trace of the zone 95 extends along two straight lines, substantially perpendicular.
• the assembly area is located in the base itself.
• the assembly then causes little deformation due to the thickness of the base.
• This solution will be adopted if the junction zone is located in a region of the reinforcement undergoing little stress.
• the location of the assembly area will be chosen according to the mechanical stresses that the blade must bear. However, in all cases, it is preferable that the weld zone be distant from the end of the base 21, opposite the fins.
• FIGS. 5B and 6A to 6E illustrate a section of the reinforcement which is produced at a determined level of the height of the reinforcement.
• This section illustrates the positioning of the assembly between the two parts forming the reinforcement.
• This positioning can be the same over the entire height of the reinforcement.
• Figure 7 illustrates a reinforcement 2 according to the invention having the same shape as the reinforcement 2 'of Figures 1 and 2, identifying the assembly area 9 or joint plane between the two component parts of the reinforcement.
• plane A located near the top 28 of the reinforcement
• plane B located in an intermediate zone
• plane C located at the foot 29 of the reinforcement.
• FIGS. 8A to 8C show that the positioning of the assembly zone differs from one plane to another.
• FIG. 8A shows that this zone 9 is located between the upper surface fin 23 and the base 21 of the reinforcement, as illustrated in FIG. 5C.
• FIG. 8B shows that this zone 9 is offset towards the base 21 of the reinforcement, in a similar manner to the variant illustrated in FIG. 6A.
• the assembly zone 9 is located in the base 21 of the reinforcement and close to the fin, similar to the variant illustrated in FIG. 6D.
• the fins generally have a variable profile depending on the height of the reinforcement and it may be preferable that the welding parameters are constant over the entire weld to simplify its production.
• the assembly can be carried out by implementing the same fusion welding technique over the entire height of the reinforcement or by using different techniques depending on the portion concerned of the reinforcement.
• the method according to the invention makes it possible to reduce the outstandings, in particular since it does not include any long heating stage prior to forming.
• the machining strategy allows significant efficiency.
• this process can also allow prototypes to be produced more quickly than the other processes because it can be implemented without heavy means (presses, tools for forming refractory materials very long to supply and very expensive, development long).
• it requires a machining machine comprising the cutting tool, a machining tool to clamp the roughs during their machining and an assembly tool.
• this process makes it possible to obtain reinforcements of complex shape since it allows access to the bottom of the reinforcement, with in particular an internal surface having a smaller radius of curvature and a specific texturing inside the reinforcement. It also makes it possible to produce reinforcements having longer fins, thereby covering a larger surface of the blade and ensuring a more resistant interface between the reinforcement and the blade on which it is bonded.
• the present invention is not limited to the modes of realization more particularly described. On the contrary, it embraces all of its variants and in particular that in which the blade is not made of a composite material but, for example, of aluminum with a reinforcement of titanium or steel alloy.

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• 2018
  • 2018-12-21 FR FR1873760A patent/FR3090437B1/fr active Active
• 2019
  • 2019-12-18 MX MX2021007282A patent/MX2021007282A/es unknown
  • 2019-12-18 EP EP19821084.1A patent/EP3898073A1/de active Pending
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