Composite aeronautical component including overmolded portion

Abstract

An aeronautical component (10) comprises a body (11) made of a composite material having a portion at least partially impregnated with a thermoplastic impregnation material (30), and a protective element (34, 44) comprising a thermoplastic construction material and attached to the portion by overmolding. The invention also relates to a method for producing such a component.

Description

Technical Field

[0001] This invention relates to an aerospace component, such as a turbine blade, for example an industrial gas turbine, an aircraft or helicopter engine turbine, or an auxiliary power unit (APU). The invention is particularly applicable to fan, turbine, and OGV rectifier blades. Background Technology

[0002] In turbojet engines (in) Figure 1 In the diagram (labeled 1), air is drawn into the intake duct 2 to pass through the fan 3, and then splits into a central main stream and secondary streams surrounding the main stream.

[0003] The main stream is compressed by the low-pressure compressor 4 and the high-pressure compressor 5 before reaching the combustion chamber 6. It then expands by passing through the high-pressure turbine 7 and the low-pressure turbine 8, and is expelled by generating auxiliary thrust. The secondary stream, in itself, is directly propelled by the fan to generate primary thrust.

[0004] Each turbine 7, 8 and fan 3 includes radially oriented impeller rings evenly spaced around the axis of rotation AX, with the housing 9 surrounding the impeller rings.

[0005] Each blade 10 supports a blade 12. The blade 12 includes a body 11 made of composite material. The blade 10 includes a root P through which it is mounted to a slot in the rotating disk of the turbojet engine. The root P extends the blade 12 along a principal direction EV, referred to as the spanwise direction. The blade 12 is the aerodynamic component of the blade and terminates at a tip. The blade includes a leading edge 13 and a trailing edge 14. The leading edge 13 is substantially parallel to the spanwise direction EV and is located upstream AM relative to the gas flow direction in the turbine. The trailing edge 14 is substantially parallel to the leading edge 13 and spaced from the leading edge 13 along an axis AX to be located downstream AV of the blade. The blade 12 terminates at a tip S. A metallic leading-edge element 15 is attached to the leading edge 13 by adhesive bonding to improve the leading edge's impact resistance and abrasion resistance. For the production of critical aerospace components, assembly by adhesive bonding is prohibited, and the production of the metallic leading-edge element limits the possibilities of manipulating its geometry to improve its performance. Finally, this leading-edge element increases the mass of high-speed moving parts.

[0006] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, states have already implemented, are implementing, or will implement various restrictions on carbon emissions. In particular, an aggressive standard applies not only to new aircraft but also to those in circulation that require technological solutions to comply with existing regulations. For many years, the civil aviation industry has been taking action to contribute to addressing climate change.

[0007] Technological research efforts have enabled significant improvements in the environmental performance of aircraft. The applicant considers all influencing factors at all design and development stages to obtain aircraft components and products that are more energy-efficient, more environmentally friendly, and have a moderate environmental impact when integrated and used in civil aviation, with the aim of improving the energy efficiency of aircraft.

[0008] Therefore, the applicant is committed to reducing its negative climate impacts through the operation of methods and benign development and manufacturing processes, as well as by minimizing greenhouse gas emissions to the minimum to reduce the environmental footprint of its activities.

[0009] This ongoing research and development effort includes next-generation aircraft engines, reducing aircraft weight (particularly through the materials used and lighter onboard equipment), developing the use of electrical technologies to ensure propulsion, and aviation biofuels as an indispensable complement to technological advancements. Summary of the Invention

[0010] Therefore, the present invention is the result of technical research aimed at significantly improving aircraft performance and thus contributing to reducing the environmental impact of aircraft. Accordingly, the present invention relates to an aerospace component comprising a body made of a composite material and a protective element, the body having a portion at least partially impregnated with a thermoplastic impregnating material, the protective element comprising a thermoplastic structural material, the protective element being attached to the portion by overmolding.

[0011] Therefore, a component with improved durability is obtained, having a lightweight body made of a thermosetting resin composite material, a portion of which is reinforced with a protective element made of a lightweight, strong, and cost-effective material. Overmolding the protective element improves durability and allows this type of reinforcement to be extended to components considered critical, such as blades. Finally, thermoplastic injection molding allows the protective element to be perfectly molded to the contours of the component, ensuring a reliable connection regardless of the component geometry, even when the attached components might have shape tolerances that are unfavorable for assembly (e.g., by bonding).

[0012] For the purposes of this application, aerospace components are those implemented in aircraft and generally comply with normative safety requirements. More specifically, the invention applies to composite engine components with aerodynamic profiles.

[0013] Other specific, non-exclusive, and optional embodiments of the invention: - An aerospace component is a turbine blade, the turbine blade comprising a blade body made of composite material extending along a main direction, the blade body having a lower surface and an upper surface, the lower surface and the upper surface being connected by a leading edge at an upstream portion of the blade body, and on the other hand, the lower surface and the upper surface being connected by a trailing edge at a downstream portion of the blade body, the upstream portion and the downstream portion being located on opposite sides of the main direction. The portion at least partially impregnated with a thermoplastic impregnating material is a portion selected from the edges of the leading edge and the trailing edge; -The protective element has serrations; - The impregnation material is selected from the following types of materials: polyetherimide, polyetheretherketone, and polyetherketone; - The thickness of the leading edge portion is essentially equal to the strands of the composite fiber; - The trailing edge is impregnated with another thermoplastic impregnation material, and the blade body includes a trailing edge element that comprises another thermoplastic structural material and is attached to the trailing edge by overmolding.

[0014] The present invention also relates to a turbine comprising the blades described above, and a method for manufacturing turbine blades, the method comprising the following steps: - The step of prefabricating a fiber preform including the leading and trailing edges of the blade body; - The step of impregnating at least a portion of one of the two edges with a first thermoplastic impregnation material; - The resin injection step; - The step of injecting thermoplastic material to form a protective element on the portion by overmolding.

[0015] Advantageously, the impregnation step includes the following steps: - The step of positioning a film made of a first thermoplastic material on the edge; - The step of applying impregnation pressure onto the thermoplastic film; - and / or the step of heating to the impregnation temperature of the thermoplastic film.

[0016] Preferably, the impregnation step includes monitoring the impregnation pressure and / or impregnation temperature, and stopping the impregnation when the impregnation pressure and / or impregnation temperature is less than a predetermined value.

[0017] According to a particular embodiment, the steps of injecting resin according to the resin transfer molding method, and / or the steps of preforming, impregnating and injecting resin, are performed in a single processing mold, which remains closed during all these steps.

[0018] Other features and advantages of the invention will become apparent from the following description of specific, non-limiting embodiments thereof. Attached Figure Description

[0019] Please refer to the attached diagram, in which: [ Figure 1 ] Figure 1 It is a schematic longitudinal cross-sectional view of an aircraft engine; [ Figure 2 ] Figure 2 It is a schematic perspective view of the turbine blades; [ Figure 3 ] Figure 3 This is a partial schematic cross-sectional view of the first and second steps of the method according to the first embodiment of the present invention; [ Figure 4 ] Figure 4 This is a partial schematic cross-sectional view of the fourth step of the method according to the first embodiment of the present invention; [ Figure 5 ] Figure 5 This is a partial schematic cross-sectional view of the fifth step of the method according to the first embodiment of the present invention; [ Figure 6 ] Figure 6 This is a partial schematic cross-sectional view of the sixth step of the method according to the first embodiment of the present invention; [ Figure 7 ] Figure 7 This is a partial schematic cross-sectional view of the seventh step of the method according to the first embodiment of the present invention; [ Figure 8 ] Figure 8 This is a partial detailed side view of the blade according to a first embodiment of the present invention; [ Figure 9 ] Figure 9 This is a partial schematic cross-sectional view of the eighth step of the method according to the first embodiment of the present invention; [ Figure 10 ] Figure 10 This is a schematic perspective view of a turbine blade according to a first embodiment of the present invention; [ Figure 11 ] Figure 11 This is a partial schematic cross-sectional view of the eighth step of the method according to the second embodiment of the present invention; [ Figure 12 ] Figure 12 This is a schematic perspective view of a turbine blade according to a second embodiment of the present invention. Detailed Implementation

[0020] Reference Figures 1 to 9A method for manufacturing a turbine blade 12 according to the present invention is described. According to a first prefabrication step, a fiber preform 20 for the body 11 of the blade 12 is manufactured. Here, the preform 20 is made of 3D woven pleated carbon fiber. In all the figures, and for clarity, the body 11 of the blade 12 has been partially shown as the upstream portion of the leading edge 13 composed of fifteen strands 21.

[0021] According to the second impregnation step, a continuous film 30 made of polyetherketone (PEK) is positioned in the first processing mold 25. Here, the film 30 consists of two parts 31 and 32, which are designed to be applied to a portion of the lower surface 16 and a portion of the upper surface 17 of the body 11, respectively, to cover the leading edge 13 over the entire height of the blade 12. Figure 3 The third step, as shown, involves introducing the preform 20 into the mold 25 to contact the membrane 30. Then, the mold 25 is closed. According to... Figure 4 In the fourth step, the two jaws 26 and 27 of the mold 25 are activated to apply impregnation pressure to the membrane 30. Here, jaws 26 and 27 are also heated to an impregnation temperature between 300 and 400 degrees Celsius. During this fourth step, a fifth step is implemented to monitor the impregnation pressure and temperature. When the impregnation pressure and / or temperature becomes lower than a predetermined value, the impregnation step is stopped by ceasing the application of pressure and heating to the membrane 30. Figure 5 ).

[0022] Different pressure and temperature parameters, along with predetermined values ​​for these parameters, are selected such that the portion 13.1 of the impregnated leading edge 13 has a thickness e that is substantially equal to the diameter of the strand 21. 13.1 ( Figure 5 ).

[0023] according to Figure 6 The sixth step of the resin injection process, as shown, involves injecting polyimide-type epoxy resin 33 into mold 25 according to a resin transfer molding method. Then, mold 25 is opened, and preform 20 (which was thus injected with epoxy resin 33 and impregnated with PEK on a portion of its leading edge 13) is removed from mold 25. Figure 7 The seventh presentation step, as shown, involves positioning the leading edge 13, which is impregnated with the film 30, in the second processing mold 40. The second mold 40 is a thermoplastic injection molding mold and has a first overmolding volume 41 having the leading edge element 34.

[0024] according to Figure 9 In the eighth assembly step shown, thermoplastic material (here, polyetheretherketone (PEEK)) is injected into mold 40 to form leading edge element 34, and then the leading edge element 34 is attached to the leading edge 13 of blade 12 by overmolding.

[0025] The first overmolding volume 41 is shaped such that the leading edge 34 obtained after overmolding has serrations 35. Figure 8 ).

[0026] This results in a blade 12, which includes a blade body 11 made of carbon fiber / epoxy composite material 33 extending along the main direction EV. The body 11 has a lower surface 16 and an upper surface 17, which are connected at an upstream portion of the body 11 by a leading edge 13 and at a downstream portion by a trailing edge 14. The upstream and downstream portions are located on opposite sides of the main direction EV, and the leading edge 13 includes a leading edge portion 13 at least partially impregnated with PEK. The blade 12 includes a leading edge element 34 made of PEEK overlaid onto the blade body 11. Figure 10 ).

[0027] according to Figure 11 and Figure 12 The second embodiment of the invention shown in the diagram impregnates the trailing edge 14 of the blade 12 with PEK in the same manner as the leading edge 13, according to the same method described above. According to this second embodiment, the second processing die 40 includes a second overmolding volume comprising a trailing edge element 44 with serrations 45. The blade 12 is then obtained, comprising a blade body 11 made of carbon fiber / epoxy composite material 33 extending along the main direction EV. The body 11 has a lower surface 16 and an upper surface 17, which are connected at an upstream portion of the body 11 via the leading edge 13, and at a downstream portion of the body 11 via the trailing edge 14. The upstream and downstream portions are located on opposite sides of the main direction EV, and the leading edge 13 includes a leading edge portion 13 at least partially impregnated with PEK. The blade 12 includes a leading edge element 34 and a trailing edge element 44, both of which are made of PEEK and are overmolded onto the blade body 11. Figure 12 ).

[0028] Of course, the present invention is not limited to the described embodiments, but covers any variations that fall within the scope of the invention as defined by the claims. In particular: -Although the preform here is composed of woven and pleated carbon fibers, the invention is also applicable to other types of preforms, such as those composed of glass fibers or aramid fibers, which may be partially co-woven, fully co-woven, or non-co-woven. The fiber preform may be interlocked or have 1D or 2D unidirectional attachment pleats; -Although the membrane applied to the leading edge here is made of polyetherketone, the invention is also applicable to other types of first thermoplastic materials, such as polyetheretherketone or polyetherimide; -Although impregnation is performed here using a continuous film applied over the entire height of the blade, the invention is also applicable to other types of impregnation, such as using a discontinuous film or spray or brush deposition, or discontinuous impregnation that is not extended over the entire height of the blade. -Although the membrane here is made of polyimide, the invention is also applicable to other types of resins, preferably thermosetting resins, such as bismaleimide type resins; Although the leading edge element here is made of polyetheretherketone, the invention is also applicable to other types of thermoplastic structural materials, such as polyetherimide or polyetherketone. The leading edge element may not be composed solely of a thermoplastic structural material, but may contain a mixture of materials comprising at least one thermoplastic material; -Although the membrane applied to the trailing edge here is made of polyetherketone, the invention is also applicable to other types of other thermoplastic impregnation materials, such as polyetheretherketone or polyetherimide; -Although the trailing edge element here is made of polyetheretherketone, the invention is also applicable to other types of other thermoplastic construction materials, such as polyetherimide or polyetherketone; -Although the component here is a turbine blade, the invention is also applicable to other types of aerospace components that support and protect elements, such as OGV distributor blades; -Although the component here is a turbine blade, the invention is also applicable to other types of aerospace components, such as housings and platforms; -Although the blade here has a trailing edge and a leading edge that support a molded protective element, the invention is also applicable to other types of blades, such as blades comprising a body made of a composite material having a metal leading edge and a trailing edge, the metal leading edge being able to be covered by a thermoplastic material to form a leading edge protective element, with an additional protective element attached to the trailing edge. The leading edge element may not be composed of a second thermoplastic material, but may contain a mixture of materials comprising at least one thermoplastic material.

Claims

1. An aerospace component (10) comprising a body (11) made of a composite material and protective elements (34, 44), the body having portions (13, 14) at least partially impregnated with a thermoplastic impregnating material (30), the protective elements comprising a thermoplastic structural material, the protective elements being attached to the portions by overmolding. in, The thickness of the portion is substantially equal to the diameter of the strands (21) of the fiber in the composite material.

2. The aircraft component (10) according to claim 1, wherein, The aerospace component (10) includes turbine blades (12), the turbine blades comprising: - A blade (12) body (11) made of composite material extending along the main direction (EV), the body (11) having a lower surface (16) and an upper surface (17), the lower surface and the upper surface being connected by a leading edge (13) at an upstream portion of the body (11), and on the other hand, the lower surface and the upper surface being connected by a trailing edge (14) at a downstream portion of the body (11), the upstream portion and the downstream portion being located on both sides of the main direction (EV); -The portion impregnated at least partially with the thermoplastic impregnation material (30) is a portion of the edge selected from the leading edge (13) and the trailing edge (14); - The protective element (34, 44) is a leading edge element (34) or a trailing edge element (44).

3. The aerospace component (10) according to claim 2, wherein, The protective elements (34, 44) have serrations (35).

4. The aircraft component (10) according to any one of the preceding claims, wherein, The impregnation material is selected from the following types of materials: polyetherimide, polyetheretherketone, and polyetherketone.

5. The aerospace component (10) according to any one of the preceding claims, wherein, The composite material is at least partially impregnated with a thermosetting resin.

6. The aerospace component (10) according to any one of the preceding claims, wherein, The protective elements (34, 44) include at least one metal reinforcement.

7. A method for manufacturing an aircraft component (10), comprising the following steps: - The step of prefabricating a fiber preform (20) of an aerospace component (10) body (11) made of composite material, the body including portions (13, 14) such as leading edge (13) or trailing edge (14). - The step of impregnating at least a portion of the portions (13, 14) with a thermoplastic impregnation material, wherein the thickness of the portions is substantially equal to the diameter of the strands (21) of the fibers of the composite material; - The step of injecting resin (33); - The step of injecting thermoplastic material to form protective elements (34, 44) on the portions (13, 14) by overmolding.

8. The manufacturing method according to claim 7, wherein, The impregnation process includes the following steps: - The step of positioning a film (30) made of thermoplastic impregnated material on the portions (13, 14); - The step of applying impregnation pressure to the membrane (30); - and / or the step of heating to the impregnation temperature of the membrane (30).

9. The manufacturing method according to claim 8, wherein, The impregnation step includes monitoring the impregnation pressure and / or the impregnation temperature, and stopping the impregnation when the impregnation pressure and / or the impregnation temperature is less than a predetermined value.

10. The manufacturing method according to any one of claims 7 to 9, wherein, The steps of injecting resin (33) according to the resin transfer molding method.

11. The manufacturing method according to any one of claims 7 to 10, wherein, The pre-forming, impregnation, and resin injection steps are carried out in a single processing mold (25), which remains closed during all these steps.

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