A supporting shaft fiber preform, and a method for manufacturing and use thereof

Abstract

The application relates to a supporting shaft fiber preform, a preparation method and use thereof, the supporting shaft fiber preform comprising a main shaft and a connecting part; the main shaft is a variable cross-section unequal-thickness columnar structure, comprising a shaft core, a first thickening layer and a second thickening layer; a pair of first clamping pieces is symmetrically arranged at the top end of the first thickening layer; the connecting part is arranged outside the second thickening layer, a pair of reserved cloth layers are arranged at the top end of the connecting part, the reserved cloth layers are folded to the top end of the second thickening layer and are sewn together, then the reserved cloth layers are folded again to form a pair of second clamping pieces; the first clamping piece and the corresponding second clamping piece are fixed together in a needle-sewing mode to form a supporting shaft fiber preform with an integrated structure. The supporting shaft fiber preform provided by the application has high structural strength, size stability and high-temperature ablation resistance, is low in cost and meets the use requirements of various complex structural parts in the aerospace field such as air rudders.

Description

Technical Field

[0001] This invention relates to the field of fiber preform preparation technology, specifically to a support shaft fiber preform, its preparation method, and its applications. Background Technology

[0002] Air rudders are a crucial component for aircraft directional control, responsible for pitch and yaw guidance to adjust flight attitude and trajectory. Their performance directly impacts the aircraft's control accuracy and stability. The rudder shaft, a vital component supporting and controlling the air rudder, bears its bending and torque moments and is typically made of metal or fiber composite materials. For high-speed aircraft, ground tests and numerical calculations demonstrate that the rudder shaft is one of the most heat-exposed parts, potentially leading to overheating or ablation. Furthermore, as a critical force-transmitting component, it must withstand significant torque loads, making its design extremely demanding.

[0003] Fiber composite materials are lighter than traditional metal materials, helping to reduce the overall weight of aircraft and improve fuel efficiency. Compared to metal control shafts, using fiber composite materials for control shafts provides better corrosion resistance, meets the requirements for long-term stability in harsh environments, extends the service life of control shafts, and reduces maintenance costs. When aerodynamic control shafts are subjected to impact or vibration, composite materials can effectively mitigate the impact force, improving the durability and stability of the control shaft. Fiber preforms, as the key reinforcing substrate of fiber composite materials, determine the overall performance of the composite material. Fiber preforms can be designed and customized with complex shapes as needed, thereby better meeting the performance and aerodynamic requirements of aircraft, improving aircraft stability and maneuverability.

[0004] CN106870553A discloses a carbon fiber composite material shaft roller for machinery. The shaft roller is made by sequentially nesting a 45 carbon steel roller core with a carbon fiber reinforced epoxy resin layer, an aluminum-based carbon fiber barrier layer, a high carbon steel reinforcement layer, a plastic protective layer, and a carbon steel connecting end sleeve. Although this can improve the overall mechanical strength and service life of the shaft roller, this layered nesting setting of metal and fiber is only suitable for general mechanical application environments. It still cannot meet the requirements of extreme application environments such as new generation aircraft with high requirements for lightweight, corrosion resistance, and ablation resistance.

[0005] Therefore, it is necessary to provide a fiber preform for the support shaft of the air rudder to meet the comprehensive development requirements of lightweight, high performance, long life, high reliability and low cost of the air rudder of the next generation of hypersonic aircraft. Summary of the Invention

[0006] To address the above problems, the present invention aims to provide a support shaft fiber preform, its preparation method, and its applications. Compared with the prior art, the support shaft fiber preform provided by the present invention has higher structural strength, dimensional stability, and high-temperature ablation resistance, and is also lower in cost, meeting the needs of the air rudders of the next generation of hypersonic aircraft.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a support shaft fiber preform, the support shaft fiber preform including a main shaft and a connecting portion disposed at the upper end of the main shaft;

[0009] The main shaft is a columnar structure with variable cross-section and unequal thickness, which includes, from the inside out, a shaft core, a first thickening layer disposed on the outside of the shaft core, and a second thickening layer disposed on the outside of the first thickening layer; a pair of first clips are symmetrically disposed at the top of the first thickening layer, and the first clips are respectively located on opposite sides of the shaft core;

[0010] The connecting part is located on the outside of the second thickened layer. A pair of reserved fabric layers are provided along the top of the connecting part. The reserved fabric layers are folded to the top of the second thickened layer and sewn together with it. Then, they are folded a second time to form a pair of second clips. The second clips are provided in correspondence with the first clips.

[0011] The first clip and its corresponding second clip are fixed together by needle stitching to form an integrated support shaft fiber preform.

[0012] In the fiber preform of the support shaft provided by the present invention, the main shaft is designed with a core, a first thickening layer and a second thickening layer arranged sequentially from the inside to the outside. The main shaft is designed as a column with variable cross-section and unequal thickness. The "variable cross-section and unequal thickness column" means that the outer diameter of the core, the first thickening layer and the second thickening layer increases sequentially from bottom to top. The present invention can adjust the diameter of different parts of the rudder shaft according to the stress conditions, so that the weight distribution of the rudder shaft is more reasonable when under stress, reducing unnecessary material use. While meeting the load-bearing capacity and bending strength required for the parts with large stress, it can also achieve the effect of weight optimization. The column structure is not particularly limited, for example, it can be cylindrical or prismatic. On the other hand, the fiber preform for the support shaft provided by the present invention is an integrated structure, which can eliminate the weaknesses of traditional joints and form a more continuous and uniform material distribution on the overall rudder shaft, increasing the rudder shaft's resistance to bending and torsion, avoiding the use of additional connectors, reducing the weight of the rudder shaft, improving the fuel efficiency of the aircraft, eliminating protrusions or uneven surfaces at traditional joints, reducing air resistance during airflow, improving the aerodynamic efficiency of the aircraft, and reducing the processing and assembly steps in the manufacturing process, thereby improving production efficiency and manufacturing quality.

[0013] In the "corresponding arrangement of the second clip and the first clip" described in this invention, "corresponding" means that the two first clips are located on opposite sides of the shaft core, and the two second clips are located on the same side of each first clip and are parallel, so that the first clip and its corresponding second clip can be fixed together to form a complete clip by needle stitching.

[0014] Preferably, the unit structure layer of the integrated structure is composed of two layers of fiber satin fabric combined with one layer of fiber mesh.

[0015] Preferably, the fiber satin fabric and the fiber mesh are each made of any one of carbon fiber, quartz fiber, mullite fiber or glass fiber.

[0016] Preferably, the areal density of the fiber satin fabric is 120-200 g / m². 2 For example, it could be 120g / m 2 130g / m 2 140g / m 2 150g / m 2 160g / m 2 170g / m 2 180g / m 2 190g / m 2 Or 200g / m 2 However, this does not limit the listed values; other unlisted values ​​within the range are also applicable.

[0017] Preferably, the areal density of the fiber mesh is 25-35 g / m². 2 For example, it could be 25g / m 2 26g / m 2 27g / m 2 28g / m 2 29g / m 2 30g / m 2 31g / m 2 32g / m 2 33g / m 2 34g / m 2 Or 35g / m 2 However, this does not limit the listed values; other unlisted values ​​within the range are also applicable.

[0018] Preferably, the diameter of the shaft is 50-70mm, for example, it can be 50mm, 52mm, 54mm, 56mm, 58mm, 60mm, 62mm, 64mm, 66mm, 68mm or 70mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the axial length of the spindle is 200-600mm, for example, it can be 200mm, 220mm, 240mm, 260mm, 280mm, 300mm, 320mm, 340mm, 360mm, 380mm, 400mm, 420mm, 440mm, 460mm, 480mm, 500mm, 520mm, 540mm, 560mm, 580mm or 600mm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0020] Preferably, the interlayer density of the support shaft fiber preform is 15-25 layers / cm, for example, it can be 15 layers / cm, 16 layers / cm, 17 layers / cm, 18 layers / cm, 19 layers / cm, 20 layers / cm, 21 layers / cm, 22 layers / cm, 23 layers / cm, 24 layers / cm or 25 layers / cm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0021] Preferably, the thickness of the first thickening layer, the second thickening layer, and the connecting portion is each independently 8-20cm, for example, it can be 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm or 20cm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0022] Preferably, the bulk density of the support shaft fiber preform is 0.75-0.95 g / cm³. 3 For example, it could be 0.75 g / cm³. 3 0.76 g / cm 3 0.77g / cm 3 0.78g / cm 3 0.79g / cm 3 0.80g / cm 3 0.82g / cm 3 0.84 g / cm 3 0.86 g / cm 3 0.88g / cm 3 0.89g / cm 3 0.90g / cm 3 0.91g / cm 3 Or 0.92g / cm 3 However, this does not limit the listed values; other unlisted values ​​within the range are also applicable.

[0023] In a second aspect, the present invention provides a method for preparing a support shaft fiber preform as described in the first aspect of the present invention, the method comprising the following steps:

[0024] The layup method is designed according to the technical requirements of the support shaft fiber preform. Unit structural layers are prepared according to the thickness requirements. The core, the first thickening layer, the second thickening layer, and the connecting part are sequentially stacked on the molding die and laid out in a conformal manner. The interlayer connection is achieved by needle punching layer by layer. The seams are sewn together with suture thread. At the same time, the first clip and the second clip are connected by needle punching to obtain an integrated support shaft fiber preform.

[0025] The preparation method provided by this invention uses processes such as lay-up, needle punching, and stitching to prepare an integrated support shaft fiber preform. This avoids the cumbersome processing and assembly steps in the existing rudder shaft preparation process, avoids the use of additional connectors, effectively reduces the weight of the rudder shaft, and reduces the risk of loosening, fatigue, and failure at the connection points. This improves the reliability and durability of the rudder shaft and reduces the need for maintenance and repair.

[0026] In this invention, the technical requirements mentioned in "designing the layup method according to the technical requirements of the support shaft fiber preform" generally refer to the technical indicators set according to the requirements of the working conditions, such as the bulk density, connection strength, heat insulation and other properties of the preform.

[0027] Preferably, the density of the layer-by-layer needle insertion is 25-30 needles / cm. 2 For example, it could be 25 stitches / cm 2 26 stitches / cm 2 27 stitches / cm 2 28 stitches / cm 2 29 stitches / cm 2 Or 30 stitches / cm 2 However, this does not limit the listed values; other unlisted values ​​within the range are also applicable.

[0028] Preferably, the spacing of the stitches is (2-6)mm×(2-6)mm, for example, it can be 2mm×2mm, 2mm×3mm, 2mm×4mm, 2mm×5mm, 2mm×6mm, 3mm×4mm, 3mm×5mm, 3mm×6mm, 4mm×5mm, 4mm×6mm or 5mm×6mm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0029] Thirdly, the present invention provides an application of the support shaft fiber preform as described in the first aspect of the present invention, the support shaft fiber preform being used as a reinforcing substrate for an air rudder shaft.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The fiber preform of the support shaft provided by the present invention adopts a columnar structure with variable cross section and unequal thickness. It can adjust the diameter of different parts of the rudder shaft according to the stress condition, so that the weight distribution of the rudder shaft is more reasonable when under stress, reducing unnecessary material use. While meeting the load-bearing capacity and bending strength required for the parts with large stress, it can also achieve the effect of weight optimization.

[0032] (2) The fiber preform of the support shaft provided by the present invention is an integrated structure, which can eliminate the weaknesses of traditional connection and form a more continuous and uniform material distribution on the whole rudder shaft, increasing the bending and torsional resistance of the rudder shaft, avoiding the use of additional connecting parts, reducing the weight of the rudder shaft, improving the fuel efficiency of the aircraft, eliminating protrusions or uneven surfaces at traditional connection, reducing air resistance, improving the aerodynamic efficiency of the aircraft, and reducing the processing and assembly steps in the manufacturing process, thus improving production efficiency and manufacturing quality.

[0033] (3) The method for preparing the support shaft fiber preform provided by the present invention uses processes such as lay-up, needle punching, and stitching to prepare an integrated support shaft fiber preform. This method avoids the cumbersome processing and assembly steps in the existing rudder shaft preparation process, avoids the use of additional connectors, effectively reduces the weight of the rudder shaft, and reduces the risk of loosening, fatigue, and failure at the connection points. This improves the reliability and durability of the rudder shaft, reduces the need for maintenance and repair, and the preparation method is simple. It can be customized according to design requirements and can achieve more complex and optimized designs to meet the performance and aerodynamic requirements of aircraft. Attached Figure Description

[0034] Figure 1 This is a front view of the fiber preform for the support shaft described in Embodiment 1 of the present invention;

[0035] Figure 2 This is a cross-sectional view of the fiber preform for the support shaft described in Embodiment 1 of the present invention;

[0036] Figure 3 This is a schematic diagram of the working state of the rudder shaft obtained by using the fiber prefabrication system of the support shaft described in Embodiment 1 of the present invention.

[0037] Among them, 1-shaft core; 2-first thickened layer; 3-second thickened layer; 4-second clamping piece; 5-first clamping piece; 6-connecting part; 7-rudder surface. Detailed Implementation

[0038] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0039] Example 1

[0040] This embodiment provides a fiber preform for a support shaft, such as Figure 1 and Figure 2 As shown, the support shaft fiber preform includes a main shaft and a connecting part 6 disposed at the upper end of the main shaft; the main shaft is a columnar structure with variable cross-section and unequal thickness, and from the inside out includes a shaft core 1, a first thickening layer 2 disposed outside the shaft core 1, and a second thickening layer 3 disposed outside the first thickening layer 2; a pair of first clips 5 are symmetrically disposed at the top of the first thickening layer 2, and the first clips 5 are respectively located on opposite sides of the shaft core 1; the connecting part 6 is disposed outside the second thickening layer 3, and a pair of reserved fabric layers are disposed along the top of the connecting part 6, the reserved fabric layers are folded to the top of the second thickening layer 3 and sewn together with it, and then folded a second time to form a pair of second clips 4, the second clips 4 being disposed corresponding to the first clips 5; the first clips 5 and the second clips 4 are fixed together by needle punching and sewing to form an integrated support shaft fiber preform;

[0041] The integrated structure's unit structure layer consists of two layers of carbon fiber satin fabric combined with one layer of carbon fiber mesh, and the areal density of the carbon fiber satin fabric is 120 g / m². 2 The areal density of the carbon fiber mesh is 28 g / m². 2 The diameter of the shaft core 1 is 60mm, the axial length of the main shaft is 500mm, the interlayer density of the fiber preform of the support shaft is 20 layers / cm, the thickness of the first thickening layer 2, the second thickening layer 3, and the connecting part 6 is each 10cm, and the bulk density of the fiber preform of the support shaft is 0.75g / cm³. 3 .

[0042] This embodiment also provides a method for preparing the above-mentioned support shaft fiber preform, the method comprising the following steps:

[0043] The layup method was designed according to the technical requirements of the support shaft fiber preform. Unit structural layers were prepared according to the thickness requirements. The layers were sequentially stacked on the molding die in the order of shaft core 1, first thickening layer 2, second thickening layer 3, and connecting part 6. Interlayer connections were achieved through layer-by-layer needle punching. Through-seam stitching was used at the seams. Simultaneously, the first clamping piece 5 and the second clamping piece 4 were connected by needle punching, resulting in an integrated support shaft fiber preform. The density of layer-by-layer needle punching was controlled at 26 needles / cm². 2 The spacing between the stitches is 4mm × 5mm.

[0044] The fiber preform for the support shaft provided in this embodiment is used as a reinforcing substrate and composited to form a rudder shaft, such as... Figure 3As shown, the rudder shaft is used to support the rudder surface 7 of the air rudder. Its bending strength is 483MPa, which is better than that of the traditional carbon steel rudder shaft (bending strength of about 400MPa), with better support, lighter weight and longer service life.

[0045] Example 2

[0046] This embodiment provides a support shaft fiber preform, which includes a main shaft and a connecting portion disposed at the upper end of the main shaft. The main shaft is a columnar structure with variable cross-section and unequal thickness, comprising, from the inside out, a shaft core, a first thickening layer disposed outside the shaft core, and a second thickening layer disposed outside the first thickening layer. A pair of first clips are symmetrically disposed at the top of the first thickening layer, and the first clips are respectively located on opposite sides of the shaft core. The connecting portion is disposed outside the second thickening layer, and a pair of reserved fabric layers are disposed along the top of the connecting portion. The reserved fabric layers are folded to the top of the second thickening layer and sewn together with it, and then folded a second time to form a pair of second clips, which are correspondingly disposed with the first clips. The first clips and the second clips are fixed together by needle punching and sewing to form an integrated support shaft fiber preform.

[0047] The integrated structure's unit structure layer consists of two layers of fiberglass satin fabric laminated with one layer of fiberglass mesh, and the areal density of the fiberglass satin fabric is 200 g / m². 2 The areal density of the glass fiber mesh is 28 g / m². 2 The diameter of the shaft core is 50 mm, the axial length of the main shaft is 200 mm, the interlayer density of the fiber preform of the support shaft is 15 layers / cm, the thickness of the first thickened layer, the second thickened layer, and the connecting part is each 8 cm, and the bulk density of the fiber preform of the support shaft is 0.95 g / cm³. 3 .

[0048] This embodiment also provides a method for preparing the above-mentioned support shaft fiber preform, the method comprising the following steps:

[0049] The layup method was designed according to the technical requirements of the support shaft fiber preform. Unit structural layers were prepared according to the thickness requirements. The layers were sequentially stacked on the molding die in the order of shaft core, first thickening layer, second thickening layer, and connecting part, and interlayer connections were achieved through layer-by-layer needle punching. Through-seam stitching was used at the seams, and the first and second clips were connected by needle punching to obtain an integrated support shaft fiber preform. The density of layer-by-layer needle punching was controlled at 27 needles / cm². 2 The spacing between the stitches is 3mm × 2mm.

[0050] The fiber preform of the support shaft provided in this embodiment is used as a reinforcing substrate to form a rudder shaft. Its bending strength is 491MPa, which is better than that of a traditional carbon steel rudder shaft (bending strength of about 400MPa). It has better support, lighter weight and longer service life.

[0051] Example 3

[0052] This embodiment provides a support shaft fiber preform, which includes a main shaft and a connecting portion disposed at the upper end of the main shaft. The main shaft is a columnar structure with variable cross-section and unequal thickness, comprising, from the inside out, a shaft core, a first thickening layer disposed outside the shaft core, and a second thickening layer disposed outside the first thickening layer. A pair of first clips are symmetrically disposed at the top of the first thickening layer, and the first clips are respectively located on opposite sides of the shaft core. The connecting portion is disposed outside the second thickening layer, and a pair of reserved fabric layers are disposed along the top of the connecting portion. The reserved fabric layers are folded to the top of the second thickening layer and sewn together with it, and then folded a second time to form a pair of second clips, which are correspondingly disposed with the first clips. The first clips and the second clips are fixed together by needle punching and sewing to form an integrated support shaft fiber preform.

[0053] The integrated structure's unit structure layer consists of two layers of carbon fiber satin fabric combined with one layer of carbon fiber mesh, and the areal density of the carbon fiber satin fabric is 150 g / m². 2 The areal density of the carbon fiber mesh is 32 g / m². 2 The diameter of the shaft core is 70 mm, the axial length of the main shaft is 600 mm, the interlayer density of the fiber preform of the support shaft is 25 layers / cm, the thickness of the first thickening layer, the second thickening layer, and the connecting part is each 16 cm, and the bulk density of the fiber preform of the support shaft is 0.81 g / cm³. 3 .

[0054] This embodiment also provides a method for preparing the above-mentioned support shaft fiber preform, the method comprising the following steps:

[0055] The layup method was designed according to the technical requirements of the support shaft fiber preform. Unit structural layers were prepared according to the thickness requirements. The layers were sequentially stacked on the molding die in the order of shaft core, first thickening layer, second thickening layer, and connecting part, and interlayer connections were achieved through layer-by-layer needle punching. Through-seam sutures were used at the seams, and the first and second clips were connected by needle punching to obtain an integrated support shaft fiber preform. The density of layer-by-layer needle punching was controlled at 29 needles / cm². 2 The spacing between the stitches is 2mm × 4mm.

[0056] The fiber preform of the support shaft provided in this embodiment is used as a reinforcing substrate to form a rudder shaft. Its bending strength is 517MPa, which is better than that of a traditional carbon steel rudder shaft (bending strength of about 400MPa). It has better support, is lighter, and has a longer service life.

[0057] In summary, the fiber preform for the support shaft provided by this invention has high structural strength, dimensional stability, and high-temperature ablation resistance, and is low in cost, meeting the needs of various complex structural components in the aerospace field, such as air rudders.

[0058] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A fiber preform for supporting shafts, characterized in that, The support shaft fiber preform includes a main shaft and a connecting part disposed at the upper end of the main shaft; The main shaft is a columnar structure with variable cross-section and unequal thickness, which includes, from the inside out, a shaft core, a first thickening layer disposed on the outside of the shaft core, and a second thickening layer disposed on the outside of the first thickening layer; a pair of first clips are symmetrically disposed at the top of the first thickening layer, and the first clips are respectively located on opposite sides of the shaft core; The connecting part is located on the outside of the second thickened layer. A pair of reserved fabric layers are provided along the top of the connecting part. The reserved fabric layers are folded to the top of the second thickened layer and sewn together with it. Then, they are folded a second time to form a pair of second clips. The second clips are provided in correspondence with the first clips. The first clip and its corresponding second clip are fixed together by needle stitching to form an integrated support shaft fiber preform.

2. The fiber preform for the support shaft according to claim 1, characterized in that, The unit structure layer of the integrated structure consists of two layers of fiber satin fabric combined with one layer of fiber mesh.

3. The fiber preform for the support shaft according to claim 2, characterized in that, The materials of the fiber satin fabric and the fiber mesh each independently include any one of carbon fiber, quartz fiber, mullite fiber or glass fiber.

4. The fiber preform for the support shaft according to claim 2, characterized in that, The areal density of the fiber satin fabric is 120-200 g / m². 2 ; The areal density of the fiber mesh is 25-35 g / m². 2 .

5. The fiber preform for the support shaft according to claim 1, characterized in that, The diameter of the shaft is 50-70mm; The axial length of the spindle is 200-600mm.

6. The fiber preform for the support shaft according to claim 1, characterized in that, The interlayer density of the fiber preform for the support shaft is 15-25 layers / cm; The thickness of the first thickening layer, the second thickening layer, and the connecting part is 8-20cm each independently.

7. The fiber preform for the support shaft according to claim 1, characterized in that, The bulk density of the fiber preform for the support shaft is 0.75-0.95 g / cm³. 3 .

8. A method for preparing a support shaft fiber preform as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: The layup method is designed according to the technical requirements of the support shaft fiber preform. Unit structural layers are prepared according to the thickness requirements. The core, the first thickening layer, the second thickening layer, and the connecting part are sequentially stacked on the molding die and laid out in a conformal manner. The interlayer connection is achieved by needle punching layer by layer. The seams are sewn together with suture thread. At the same time, the first clip and the second clip are connected by needle punching to obtain an integrated support shaft fiber preform.

9. The method for preparing the fiber preform of the support shaft according to claim 8, characterized in that, The density of the layer-by-layer needle insertion is 25-30 needles / cm. 2 ; The spacing of the sutures is (2-6) mm × (2-6) mm.

10. Use of a fiber preform for supporting shafts as described in any one of claims 1-7, characterized in that, The support shaft fiber preform is used as a reinforcing substrate for the air rudder shaft.

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