Method for manufacturing a fibre preform for a wheel blade

Abstract

The invention relates to a method for manufacturing a fibrous preform (15), the method comprising the steps of: (a) providing a blank (22) comprising at least a first layer and a second layer (23, 24), the first and second layers each comprising weft yarns (26), the weft yarns of each of the first and second layers being interconnected by the same warp yarns (27); (b) untying the warp and weft yarns on a portion (Pi) of the first layer to form a floating yarn (28); (c) cutting the floating yarn, characterized in that step (c) comprises the sub-steps of: - (co) positioning a protective mat (29) between the floating yarn of the first layer and the second layer, and - (cl) cutting the floating yarn with an electric rotary cutting tool (30).

Description

Technical Field

[0001] This invention relates to the field of methods for manufacturing fiber preforms for aircraft turbine engine blades.

[0002] The present invention relates in particular to the field of methods for manufacturing fiber preforms, the method comprising the step of cutting the fiber preforms. Background Technology

[0003] Aircraft turbine engines typically have a longitudinal axis. An aircraft turbine engine, for example, includes, from upstream to downstream, a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, and exhaust nozzles, in the direction of gas flow along the longitudinal axis.

[0004] The fan allows airflow to be drawn in, which is then split into a main stream and a secondary stream. The main stream flows through the main duct of the turbine engine, while the secondary stream is directed toward the secondary ducts surrounding the main duct.

[0005] The main stream is compressed within the compressor. The compressed air is then mixed with fuel and burned in the combustion chamber. The combustion gases pass through a turbine and are then expelled through a nozzle whose cross-section allows the gases to be accelerated to produce propulsion.

[0006] A fan typically consists of a moving disc that rotates about a longitudinal axis and blades that extend radially from the disc.

[0007] Each blade typically comprises radially extending blades with an aerodynamic shape. Therefore, the blades have a pressure side and a suction side connected by a leading edge and a trailing edge. Blades typically have a variable thickness, particularly a thickness that decreases in the trailing edge direction.

[0008] Turbine blades can be made of metallic materials. However, in order to reduce the overall weight of the turbine engine while maintaining the mechanical properties of the blades, it has been proposed to make the blades from composite materials. Composite materials for turbine blades typically consist of a polymer matrix and fibers embedded within the polymer matrix. For example, the polymer matrix is ​​epoxy resin. The fibers are, for example, glass fibers or carbon fibers. The fibers are typically formed in the form of three-dimensional fiber preforms of the blade.

[0009] Three-dimensional fiber preforms typically consist of multiple layers of woven yarn. The number of layers depends on the thickness of the sheaves. Each layer consists of weft yarns that are interconnected by the same warp yarns, thus forming the layer's weave.

[0010] To provide impellers with variable thickness, it is necessary to manufacture three-dimensional fiber preforms with the same variable thickness. Fiber preforms with variable thickness produce fiber preforms with varying yarn layer counts. To produce such preforms, a preform blank is first produced. In this step, the preform blank has a constant thickness equal to the maximum thickness of the impeller. Then, warp yarns are removed from a portion of the layers, causing the warp and weft yarns to unwind in that portion. The unwoven and thus unwound warp and weft yarns are commonly referred to as "floats." These floats are then cut to obtain a fiber preform with variable thickness.

[0011] While this manufacturing method provides fiber preforms with variable thickness, it is not entirely satisfactory. In practice, the cutting of the floating yarn is a manual operation performed by an operator using cutting scissors. Therefore, it is a tedious, lengthy, and expensive step. Furthermore, manually performing this step poses a health risk to the operator who must expend considerable effort to cut the blank.

[0012] Finally, because the blanks are cut manually, there is a high risk of accidentally cutting the braided yarn from the bottom layer that was never intended to be cut. This creates the risk of non-compliance and impeller scrap.

[0013] Therefore, there is a need to provide a solution that delivers fiber preforms with variable thickness in a simple, fast, reliable and inexpensive manner. Summary of the Invention

[0014] Therefore, the present invention proposes a method for manufacturing fiber preforms for turbine blades of aircraft turbine engines, the method comprising the following steps: (a) A preform with three-dimensional weaving is provided, the preform comprising at least a first layer and a second layer of woven yarns, each of the first and second layers comprising weft yarns, the weft yarns of each of the first and second layers being interconnected by the same warp yarns. (b) Untie the warp and weft yarns on a portion of the first layer to form a floating yarn, and (c) Cut the floating yarn from this part of the first layer.

[0015] The significant feature of this manufacturing method is that step (c) includes the following sub-steps: (c0) Position the protective pad between the first layer of floating yarn and the second layer, and (c1) Cut the floating yarn with an electric rotary cutting tool.

[0016] Therefore, according to the present invention, the step of cutting the blank uses a protective pad on the one hand and an electric cutting tool on the other.

[0017] Electric cutting tools enable efficient cutting of loose yarns in the blank, meaning that the operator can do so effortlessly, or more precisely, it limits the risk of accidentally cutting a second layer of yarn and provides improved safety for the operator.

[0018] In addition, the protective pad protects the second layer of yarn from accidental cuts during the operation of the cutting tool, which improves the reliability of the cutting step by reducing waste.

[0019] This invention may include one or more of the following features, used individually or in combination: - The cutting tool includes a grip handle and a rotating cutting blade attached to the grip handle. - The rotary cutting blade is circular and rotates around its axis of rotation. - The diameter of the rotary cutting blade is between 20mm and 100mm, preferably between 30mm and 50mm. - The rotary cutting blade consists of metal material. The cutting tool also includes a housing that is mounted around the rotating cutting blade and has a suction channel. - The shell is made of polymer material. - The cutting tool includes a motor for driving the rotating cutting blade. - The protective pad contains a polymer material, preferably a thermoplastic. - The thickness of the protective pad is between 1mm and 10mm, preferably between 1mm and 5mm.

[0020] The present invention also relates to a method for manufacturing turbine blades for an aircraft turbine engine, the method comprising the following steps: - A fiber preform is provided according to a method for manufacturing a fiber preform according to any of the above features. - To densify the fiber preforms.

[0021] Advantageously, the densification step includes the following steps: - Arrange the fiber preforms in the mold, and - Inject the resin into the mold. Attached Figure Description

[0022] Further features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings, in which: Figure 1 This is a schematic diagram of the longitudinal cross-section of one half of an aircraft turbine engine. Figure 2 This is a schematic perspective view of the blades. Figure 3 yes Figure 2A schematic perspective view of a portion of the fiber preform of the impeller. Figure 4 This is a schematic cross-sectional view of the fiber preform blank along a plane parallel to a third direction in the first step of a method for manufacturing fiber preforms. Figure 5 This is a schematic cross-sectional view of the preform along a plane parallel to a third direction in the second step of a method for manufacturing fiber preforms. Figure 6 This is a schematic cross-sectional view of the preform along a plane parallel to a third direction in the third step of a method for manufacturing fiber preforms. Figure 7 This is a perspective view of the cutting tool according to the present invention. Figure 8 This is a schematic diagram of the manufacturing method according to the present invention. Detailed Implementation

[0023] Figure 1 An example of a turbine engine 1 for use in an aircraft is shown. The turbine engine 1 extends about and along the longitudinal axis A.

[0024] In this application, the terms "upstream" and "downstream" are defined relative to the direction of gas flow along the longitudinal axis A in the turbine engine 1.

[0025] The terms “axial,” “axially,” “radial,” and “radially” are defined relative to the longitudinal axis A.

[0026] The terms “inner,” “internal,” “inner,” “outer,” “external,” and “external” are defined relative to the distance from the longitudinal axis A along the radial axis.

[0027] Preferably, the turbine engine 1 is a turbojet engine, such as a turbojet engine with a dual-body and dual-flow configuration. The turbine engine includes, from upstream to downstream, a fan 2, at least one compressor (e.g., a low-pressure compressor 3 and a high-pressure compressor 4), a combustion chamber 5, at least one turbine (e.g., a high-pressure turbine 6 and a low-pressure turbine 7), and an exhaust nozzle.

[0028] The low-pressure compressor 3 and the high-pressure compressor 4, as well as the high-pressure turbine 6 and the low-pressure turbine 7, each include at least one rotor. The rotor of the low-pressure compressor 3 is connected to the rotor of the low-pressure turbine 7 via a low-pressure shaft 8, and the rotor of the high-pressure compressor 4 is connected to the rotor of the high-pressure turbine 6 via a high-pressure shaft 9. The high-pressure shaft 9 is arranged coaxially around the low-pressure shaft 8. The low-pressure shaft 8 and the high-pressure shaft 9 are centered on the longitudinal axis A.

[0029] The fan 2 includes a movable disk that rotates about a longitudinal axis A and blades 10 extending radially from the disk. The fan 2 also includes a fan shaft 2a, which is connected to a low-pressure shaft 8, for example, via a reducer 11.

[0030] The fan 2 can be ducted. Therefore, the turbine engine 1 can include a fan housing 2b. The fan housing 2b is annular and centered on the longitudinal axis X. The fan housing is arranged around the impeller blade 10. According to another example, the fan 2 can be non-ducted.

[0031] Fan 2 enables the intake of airflow F, which is divided into a primary airflow F1 and a secondary airflow F2. The primary airflow F1 passes through the main duct v1 of turbine engine 1, and the secondary airflow F2 flows into the secondary duct v2 of turbine engine 1. The secondary duct v2 surrounds the primary duct v1.

[0032] In mainstream F1 combustion, air is compressed in low-pressure compressor 3, and then in high-pressure compressor 4. The compressed air is then mixed with fuel and burned in combustion chamber 5. The combustion gases pass through high-pressure turbine 6 and low-pressure turbine 7. Finally, the gases escape through nozzles whose cross-section allows them to be accelerated to generate propulsion.

[0033] refer to Figure 2 Each blade 10 includes a blade 12 extending between a tip 13 and a root 14. The blade 12 has an aerodynamic shape and includes a pressure side 12i and a suction side (not visible), which are connected by a leading edge 12a and a trailing edge 12b.

[0034] Each blade 10 has a variable thickness. For example, the first thickness e1 of the blade 10 measured at the leading edge 12a is greater than the second thickness e2 measured at the trailing edge 12b. In particular, the thickness of the blade 10 decreases in the direction of the trailing edge 12b.

[0035] According to the present invention, each blade 10 comprises a composite material. The composite material has an organic matrix, also known as the acronym CMO. Therefore, the composite material comprises fibers embedded in the organic matrix. For example, the fibers are glass fibers, or carbon fibers, or ceramic fibers, or polyester fibers, or polypropylene fibers, or polyamide fibers. For example, the organic matrix is ​​selected from thermosetting polymers (such as epoxy resins) or thermoplastic polymers (such as polyolefins).

[0036] The fibers are typically formed in the form of a three-dimensional fiber preform 15 of the blade 10.

[0037] refer to Figure 3The fiber preform 15 comprises multiple layers 16, 17, and 18 of woven yarns. These layers 16, 17, and 18 are stacked in a first direction X1 defining the thickness of the fiber preform 15. Each layer 16, 17, and 18 includes a weft yarn 20 extending along a second direction X2. The weft yarns 20 of these layers 16, 17, and 18 are joined together by warp yarns 21 extending in a third direction X3 perpendicular to the first direction X1 and the second direction X2. In other words, the weft yarns 20 and warp yarns 21 of these layers 16, 17, and 18 are interwoven to form a fabric. Advantageously, the fabric is of the linked type. Any other type of fabric is suitable for the invention.

[0038] The fiber preform 15 has a variable thickness that is either along a chord of the profile of the blade 10 or along the longitudinal axis A, depending on the profile of the blade 10. The fiber preform 15 includes at least a first portion P1 having a first thickness e1' and a second portion P2 having a second thickness e2', for example, the second thickness being less than the first thickness e1'. In the first portion P1 of the fiber preform 15, the number of layers 16, 17, and 18 is greater than the number of layers 16, 17, and 18 in the second portion P2.

[0039] Now refer to Figure 8 An example of a method for manufacturing the blade 10 is described. The method for manufacturing the blade 10 may include the following steps: (100) Provide fiber preform 15, and (200) to densify the fiber preform 15.

[0040] The densification step (200) may include the following steps: (201) Arrange the fiber preform 15 in the mold, and (202) Inject the resin into the mold.

[0041] According to the present invention, a method for manufacturing fiber preform 15 includes the following steps: (a) A blank 22 is provided for the fiber preform 15, the blank 22 comprising a first layer 23 and a second layer 24 of braided yarns and at least one third layer 25 of possible braided yarns, the first layer 23 and the second layer 24 each comprising weft yarns 26, the weft yarns 26 of each of the first layer 23, the second layer 24 and the third layer 25 being interconnected by the same warp yarns 27. (b) Untie the warp yarns 27 and weft yarns 26 on the first portion P11 of the first layer 23 to form a floating yarn 28, and (c) Cut the floating yarn 28 from the first part P11 of the first layer 23.

[0042] refer to Figure 4In step (a), the blank 22 of the fiber preform 15 of the blade 12 has a constant thickness e11. During this step (a), the thickness e11 of the blank 22 is equal to the first thickness e1' of the first portion P1 of the fiber preform 15.

[0043] In step (a), advantageously, the weaving of the yarns of the blank 22 is of the continuous type.

[0044] refer to Figure 5 During step (b), the warp yarn 26 is pulled out, for example manually, from the first portion P11 of the blank 22. At the end of step (b), in the first portion P11, the warp yarn 27 and the weft yarn 26 are untied and therefore no longer interlaced. The warp yarn 27 and the untied weft yarn 26 are the float yarn 28.

[0045] Reference Figure 6 According to the present invention, step (c) of cutting the floating yarn 28 includes the following steps: (c0) Position the protective pad 29 between the floating yarn 27 of the first layer 23 and the yarns 26, 27 of the second layer 24, and (c1) Cut the floating yarn 28 with an electric rotary cutting tool 30.

[0046] During the cutting step (c), the protective pad 29 protects the yarn of the second layer 25 to limit the risk of accidental cutting of the yarn of the second layer 25.

[0047] For example, the protective pad 29 can extend along the second direction X2 and the third direction X3 throughout the first part P11.

[0048] The protective pad 29 comprises a polymer material. The polymer material can be a thermoplastic polymer or a thermosetting polymer. For example, the thermoplastic polymer is selected from polyolefins, fluoropolymers, fluoropolymers, polymers, polyesters, or even polychlorinated compounds. Preferably, the thermoplastic polymer is polyvinyl chloride (PVC). For example, the thermosetting polymer is selected from epoxy resins.

[0049] The protective pad 29 may include multiple stacked protective layers. For example, the protective pad 29 may include three protective layers 29.

[0050] Advantageously, the thickness of the protective pad 29 is between 1 mm and 10 mm, preferably between 1 mm and 5 mm, and even more preferably 3 mm. This thickness of the protective pad 29 facilitates operation while ensuring effective protection of the yarn of the second layer 25 during the cutting step (c).

[0051] The rotary and electric cutting tool 30 allows the operator to cut quickly and effortlessly. Compared to manual cutting without an electric cutting tool, operator health is protected, and manufacturing speed is increased. The cutting tool 30 enables precise cutting and further limits the risk of accidentally cutting the yarn from the second layer 24.

[0052] Preferably, the cutting tool 30 includes a grip handle 31 and a rotating cutting blade 32 connected to the grip handle 31.

[0053] The handle 31 makes it easier to hold the cutting tool 30. The handle 31 has an elongated shape. This shape of the handle 31 improves operator safety by allowing the rotating cutting blade 32 to be removed.

[0054] The grip handle 31 may include a coating. In particular, the coating comprises a polymeric material, such as polyurethane or polyamide.

[0055] The rotary cutting blade 32 has a circular or annular shape. Therefore, the rotary cutting blade has a rotation axis R. The diameter of the rotary cutting blade 32 is, for example, between 20 mm and 100 mm, preferably between 30 mm and 50 mm, and even more preferably 45 mm. The diameter of the rotary cutting blade can be adjusted according to the size of the blank 22. The rotational speed of the rotary cutting blade 32 can be between 150 rpm and 300 rpm, preferably between 200 rpm and 250 rpm, and even more preferably 240 rpm, where rpm corresponds to the expression "revolutions per minute".

[0056] The rotary cutting blade 32 comprises a metallic material, such as titanium. This material enables efficient cutting of the floating yarn 27. The rotary cutting blade 32 may be diamond-coated.

[0057] according to Figure 7 In the advantageous embodiment shown, the cutting tool 30 includes a housing 33 mounted around the rotating cutting blade 32. Advantageously, the housing 33 includes a semi-annular body 34 centered on the axis of rotation R and a suction conduit 35 extending protruding from the body 34.

[0058] The main body 34 is connected to the grip handle 31 and is mounted in a fixed manner around the rotating cutting blade 32.

[0059] The suction pipe 35 allows for the removal of debris generated during the cutting step (c), thereby preventing contamination of the blank 22 and consequently, the fiber preform 15. The diameter of the suction pipe 35 can be between 20 mm and 50 mm, preferably between 20 mm and 30 mm, and even more preferably 27 mm. The suction pipe 35 can be connected to a suction device.

[0060] Preferably, the housing 33 is made of a polymer material. This allows for a reduction in the overall weight of the cutting tool 30.

[0061] The cutting tool 30 includes a motor for driving the cutting blade 30, as not shown.

[0062] Thanks to the automatic cutting tool 30 and protective pad 29 according to the present invention, the blank 22 of the fiber preform 15 can be cut effectively, reliably, quickly and safely.

Claims

1. A method for manufacturing a fiber preform (15) for a blade (12) of an aircraft turbine engine (1), the method comprising the steps of: (a) A blank (22) having a three-dimensional weave is provided, the blank (22) comprising at least a first layer and a second layer (23, 24) of woven yarns, the first layer and the second layer (23, 24) each comprising a weft yarn (26), the weft yarns (26) of each of the first layer and the second layer (23, 24) being interconnected by the same warp yarns (27), (b) Unwind the warp yarns (27) and weft yarns (26) on a portion (P11) of the first layer (23) to form a floating yarn (28), and (c) Cut the floating yarn (28) from this portion (P11) of the first layer (23). The characteristic feature is that step (c) includes the following sub-steps: (c0) Position the protective pad (29) between the float (28) of the first layer (23) and the second layer (24), and (c1) Cut the floating yarn (28) with an electric rotary cutting tool (30).

2. The manufacturing method according to the preceding claim, characterized in that, The cutting tool (30) includes a grip handle (31) and a rotating cutting blade (32) connected to the grip handle (31).

3. The manufacturing method according to the preceding claim, characterized in that, The rotary cutting blade (32) is circular and rotates about its axis of rotation (R).

4. The manufacturing method according to claims 2 and 3, characterized in that, The diameter of the rotary cutting blade (32) is between 20 mm and 100 mm, preferably between 30 mm and 50 mm.

5. The manufacturing method according to claim 2, 3, or 4, characterized in that, The rotary cutting blade (32) is made of metal.

6. The manufacturing method according to any one of claims 2 to 5, characterized in that, The cutting tool (30) also includes a housing (34) which is mounted around the rotating cutting blade (32) and has a suction channel (35).

7. The manufacturing method according to the preceding claim, characterized in that, The housing (34) is made of polymer material.

8. The manufacturing method according to claim 2 or any of the preceding claims in conjunction with claim 2, characterized in that, The cutting tool (30) includes a motor for driving the rotating cutting blade (32).

9. The manufacturing method according to any one of the preceding claims, characterized in that, The protective pad (29) comprises a polymer material, preferably a thermoplastic.

10. The manufacturing method according to any one of the preceding claims, characterized in that, The thickness of the protective pad (29) is between 1 mm and 10 mm, preferably between 1 mm and 5 mm.

Images