A three-dimensional woven composite material leaf spring landing gear preform copying molding tool and molding method

Abstract

The present invention discloses a three-dimensional woven composite leaf spring landing gear preform imitation molding tool and molding method, including a tool frame, a core mold, five clamps, and five connecting rods. The three-dimensional woven composite leaf spring landing gear structure preform includes nine regions: uniform cross-section region 1, variable cross-section region 1, uniform cross-section region 2, variable cross-section region 2, uniform cross-section region 3, variable cross-section region 3, uniform cross-section region 4, variable cross-section region 4, and uniform cross-section region 5. The leaf spring has vertical sections on both sides and a circular arc section in the middle, forming a symmetrical structure. The fabric thickness varies in different regions. Variable thickness integrated weaving is adopted during the weaving process. The fabric region includes connecting warp and weft yarns. The present invention can solve the defects of existing landing gear preforms that are woven in blocks and cannot be integrated, and achieve better dimensional control and good mechanical properties. The use of three-dimensional woven composite materials not only has the characteristics of high specific stiffness and high specific strength, but also has excellent anti-delamination and impact resistance.

Description

Technical Field

[0001] The invention relates to the technical field of textile machinery structures, in particular to a three-dimensional woven composite material leaf spring type landing gear preform copying molding tool and a molding method. Background Art

[0002] With the rapid development of drones, demands for higher takeoff quality, cruising speed, and energy efficiency are rising. Composite landing gear has emerged as a result. Compared to high-performance metal materials such as 300M steel, 4340 steel, and TC18 titanium alloy used in aviation, carbon fiber-reinforced composites (CFRPs) offer not only high strength, high modulus, and excellent fatigue and corrosion resistance, but also lightweight and highly designable properties, which are beneficial for reducing fuel consumption and improving flight endurance. Three-dimensional woven composites are currently the most widely used three-dimensional textile composites. The fabric structure incorporates binding yarns through the thickness, which are then interlocked with the in-plane yarns to form a spatially integrated interlocking structure. This enhances the interlaminar properties of the composite after molding, inhibits delamination, and improves impact resistance and damage tolerance. Given this background, the application of 3D woven composites in landing gear will effectively address the problems associated with the use of original metal landing gear, reduce weight, and further enhance the overall performance of ship-borne unmanned helicopters.

[0003] Currently, the molding of three-dimensional woven composite landing gear preforms mostly adopts partial weaving and subsequent assembly, but the connection parts are prone to stress concentration and have poor mechanical properties. For example, patent CN110126300 provides a composite landing gear using three-dimensional weaving and a preparation method thereof. It adopts a three-point structural layout, and the support center axis and the wheel rocker arm both use three-dimensional woven components, which can achieve a lightweight design of the landing gear, but its overall structural performance is poor; CN108146617 designs and manufactures a composite leaf spring landing gear and a manufacturing method thereof, in which a foam layer is filled inside the continuous fiber shell. Although the landing gear is lightweight, the interior is a foam layer, and the load-bearing capacity is poor compared to composite material plates, and the mechanical properties are poor.

[0004] To this end, we propose a three-dimensional woven composite leaf spring landing gear preform copy molding tool and molding method to solve the above problems. Summary of the Invention

[0005] The object of the present invention is to provide a three-dimensional woven composite material leaf spring landing gear preform copy molding tool and molding method to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The first purpose is to provide a three-dimensional woven composite material leaf spring landing gear preform copy molding tool, which includes a tool frame, a core mold, five clamps, and five connecting rods.

[0008] The fixture 1 includes a bearing, ten shaft fans, and two pillars. The bearing is equipped with two bearing discs, a connecting rod, two arched limit blocks, and a small motor. Each bearing disc has a positioning hole at its center with a diameter of 50mm. The lower part of the bearing disc has five symmetrically distributed "U"-shaped grooves, each with two limit holes (1) with a diameter of 16mm. A connecting rod passes through the central positioning hole of the bearing disc to connect the two bearing discs horizontally. Each bearing disc has an arched limit block on its outer side. The diameter of the connecting rod matches the diameter of the positioning hole and the arc of the arched limit block. The two arched limit blocks are symmetrically distributed. The lower ends of the two arched limit blocks are connected to the pillars and connected by welding. The shaft fan is runway-shaped, with a length of 1200mm and an arc diameter of 16mm. There are two limit holes at the upper end of the shaft fan, corresponding to the size of the 'U'-shaped groove of the bearing disk. There is a runway-shaped hole at the lower end, with a length of 400mm, 27mm away from the lower end of the shaft fan. The ten shaft fans correspond to the 'U'-shaped grooves on the two bearing disks. There are five shaft fans on each bearing disk, which are fixed by bolts passing through the 'U'-shaped grooves and the limit holes at the upper end of the shaft fans.

[0009] The core mold has an arched symmetrical structure, with each side composed of sixteen 'Z'-shaped core blocks and one vertical core block interlaced and combined, connected in the middle by a convex core block, the upper ends of the two vertical core blocks are curved and fit into the lower ends of the 'Z'-shaped core blocks, each core block is provided with two positioning holes, a connecting rod passes through the positioning holes and the runway-shaped holes on the shaft fan to connect the core mold to the tooling frame, and is fixed with a hexagonal nut to complete the combination of the core mold and the tooling frame; a small motor is provided on the right side of the bearing, so that the ten shaft fans drive the core mold to rotate around the bearing, thereby realizing the rotation of the tooling;

[0010] The clamp consists of two splints and two small connecting rods. Three positioning holes are provided at both ends of the splints. The diameter of the positioning holes is 16 mm. During the weaving process, one side of the splint is close to the core mold and the other side is close to the fabric. Two small connecting rods are used to connect through the positioning holes and the two splints are clamped by hexagonal nuts to make the fabric fit the core mold better and achieve the purpose of shape-matching.

[0011] The second object is to provide a three-dimensional woven composite material leaf spring landing gear preform, the three-dimensional woven composite material leaf spring landing gear preform comprising nine regions, namely, a uniform cross-section region 1, a variable cross-section region 1, a uniform cross-section region 2, a variable cross-section region 2, a uniform cross-section region 3, a variable cross-section region 3, a uniform cross-section region 4, a variable cross-section region 4, and a uniform cross-section region 5. The preform has vertical sections on both sides of the leaf spring and an arc section in the middle, presenting a symmetrical structure. The fabric thickness varies in different regions, and variable thickness integrated weaving is adopted during the weaving process. The fabric region comprises binding warp yarns and weft yarns, and the specific fabric parameters are set as follows:

[0012] The developed fabric has an arch height of 500mm and a span of 2000mm. The inner length of the entire leaf spring is 2368mm and the width is 185mm. The length of the uniform cross-section area 1 is 100mm, the arc length of the variable cross-section area 1 is 20mm, the length of the uniform cross-section area 2 is 264mm, the length of the variable cross-section area 2 is 443mm, and the length of the uniform cross-section area 3 is 714mm. It has a symmetrical structure. The lengths of the variable cross-section area 3 and the variable cross-section area 2 are equal, the lengths of the uniform cross-section area 4 and the uniform cross-section area 2 are equal, the lengths of the variable cross-section area 4 and the variable cross-section area 1 are equal, and the lengths of the uniform cross-section area 5 and the uniform cross-section area 1 are equal.

[0013] The warp yarn is TG800H-12K carbon fiber triple-ply, and the weft yarn is TG800H-12K single-ply;

[0014] The density of the warp yarns is 4 / cm, and the density of the weft yarns is 5 / cm;

[0015] Number of binding warp yarn rows n = fabric width × warp yarn density = 185 / 10 × 4 = 74 rows;

[0016] The volume content of fabric fiber is controlled at about 57%.

[0017] The third object is to provide a method for preparing a three-dimensional woven composite material leaf spring landing gear preform, wherein the weaving method comprises the following steps:

[0018] S1, tooling preparation, initial fabric arrangement, warp yarn hanging 74 rows, then weft insertion, according to the fabric thickness, calculate the number of weft insertion layers in each area;

[0019] S2, weaving of uniform cross-section area 1:

[0020] S2-1: In this area, the fabric is in a vertical state and the thickness does not change. The fabric thickness is measured to be 25 mm, and the number of warp and weft yarn layers introduced is calculated. At the same time, the weaving tooling is controlled during the weaving process to ensure that the fabric thickness is evenly distributed. The fabric thickness is measured every 20 mm during the weaving process to ensure that the thickness distribution is uniform.

[0021] S2-2: Based on the fabric thickness, 33 warp yarn layers and 34 weft yarn layers are introduced. During the weaving process, four hexagonal nuts in the fixture are used to clamp the fabric and the core mold together, ensuring that they are closely attached to the inside of the core mold to achieve the purpose of contour molding. After the inner length of the woven landing gear preform reaches 100 mm, the next weaving area is entered.

[0022] S3, weaving of variable cross-section area 1:

[0023] S3-1, this area is a variable thickness area, which is in the shape of a "corner". The inner length of the fabric is 20mm, and the fabric thickness increases from 25mm to 26mm and then decreases to 20mm. The change in fabric thickness is achieved by adding and subtracting layers of yarn during the weaving process, and the curved shape of the fabric is maintained by controlling the angle of the weaving tooling;

[0024] S3-2, when the total inner length of the fabric is 100mm, the yarn is added, the warp yarn is added one layer, becoming 34 layers, the weft yarn is 35 layers, and the fabric thickness reaches 26mm. Then the yarn is reduced, and one layer of outer warp yarn is reduced for each weft weaving, for a total of 8 layers. At this time, the warp yarn has 26 layers. At the same time, during the weaving process, the motor is used to drive the shaft fan to rotate around the bearing to control the angle of the weaving tooling so that the cloth fell is always parallel to the yarn direction. At the same time, the clamp is used to make the fabric fit better with the core mold to achieve shape-matching. When the inner length of the preform reaches 120mm, it enters the next area for weaving;

[0025] S4, weaving of the second uniform cross-section area:

[0026] S4-1, the fabric thickness in this area does not change. The fabric thickness is measured and is still 20mm. The design introduces the number of warp and weft yarn layers. The fabric in this area has a certain curvature. Therefore, tooling is used to ensure the curved surface of the fabric to achieve contour shaping. At the same time, the fabric thickness is measured every 20mm during the weaving process to ensure that there is no obvious deviation in the fabric thickness.

[0027] S4-2: Calculate the number of warp yarn layers to 26 and the number of weft yarn layers to 27. Use a motor to make the bearing disk drive the shaft fan to rotate around the bearing to control the angle of the weaving tool. Use a clamp to make the fabric fit tightly to the surface of the core mold to ensure the curved surface of the fabric. Weave 264mm. At this time, the total length of the inner side of the fabric is 384mm. Enter the next weaving area.

[0028] S5, weaving of variable cross-section area 2:

[0029] S5-1, the fabric thickness in this area increases evenly, the fabric has a certain curvature, and the thickness increases from 20mm to 37mm. This is achieved by uniformly adding layers of warp yarns. The angle of the weaving tooling is controlled during the weaving process to achieve better fabric shaping.

[0030] S5-2: The initial number of warp yarn layers in this area is 26. A layer of warp yarn is added to the outside every 26 mm, for a total of 17 layers, so that the final fabric thickness reaches 37 mm. At this time, the number of warp yarn layers of the fabric increases to 48. At the same time, during the weaving process, the bearing plate is used to drive the shaft fan to rotate around the bearing to control the angle of the weaving tool. The clamp is used to make the fabric fit tightly to the surface of the core mold to ensure the curved surface of the fabric. After weaving 443 mm, the total length of the inner side of the fabric is 827 mm, and then weaving enters the next area;

[0031] S6, weaving of uniform cross-section zone 3:

[0032] S6-1, the top area of ​​the landing gear where it connects to the fuselage. The fabric thickness in this area is 37mm and does not vary. During the weaving process, the weaving tooling is controlled to maintain fabric curvature. The fabric thickness is measured every 20mm to ensure uniform thickness distribution.

[0033] S6-2, based on the thickness calculation, 48 layers of warp yarn and 49 layers of weft yarn are introduced, without adding layers of warp and weft yarn. During the weaving process, the splint 22 and the hexagonal nut 21 are used to make the fabric close to the surface of the core mold to ensure the curvature of the fabric. After weaving 714 mm, the inner length of the fabric reaches 1541 mm, and the next weaving area is entered;

[0034] S7, weaving of variable cross-section area 3:

[0035] S7-1, the variable cross-section area three is symmetrical with the variable cross-section area two. The arc length of this area is 443mm, and the fabric thickness is 37mm. The fabric thickness in this area is uniformly thinned from 37mm to 20mm. This is achieved by uniformly reducing the warp yarn layer. The angle of the weaving tooling is controlled to ensure the curved surface of the fabric. At the same time, the fabric thickness is measured every 20mm during the weaving process to ensure that its thickness is within a certain range without large deviations.

[0036] S7-2: In the initial stage, the number of warp yarn layers is 48 and the number of weft yarn layers is 49. The number of outer warp yarn layers is reduced by one layer every 26 mm, for a total of 17 layers, and the weaving process is 443 mm. At this time, the fabric thickness is 20 mm, and the number of warp yarn layers is reduced to 26. During the weaving process, the motor drives the shaft fan to rotate around the bearing to control the angle of the weaving tooling. The cloth fell is always parallel to the yarn direction. The two clamps are clamped with hexagonal nuts, so that the fixture clamps the fabric and the core mold to obtain a certain curved surface. At this time, the total length of the inner side of the fabric reaches 1984 mm, and weaving enters the next area;

[0037] S8, weaving of uniform cross-section zone 4:

[0038] S8-1, the uniform cross-section area 4 is symmetrical with the uniform cross-section area 2. This area is the uniform thickness area with a thickness of 20 mm. The thickness distribution is uniform and there is no obvious change. The thickness of the fabric is measured every 20 mm during the weaving process to ensure its uniform thickness distribution. The angle of the weaving tooling is controlled to ensure the curved surface of the fabric.

[0039] S8-2, according to thickness calculation, 26 layers of warp yarn and 27 layers of weft yarn need to be introduced. During the weaving process, the motor drives the shaft fan to rotate around the bearing to control the angle of the weaving tool. The splint and hexagonal nut are used to make the fabric close to the surface of the core mold to ensure the curved surface. After weaving 264mm, the total length of the inner side of the fabric reaches 2248mm, and then enters the next stage of weaving;

[0040] S9, weaving of variable cross-section area 4:

[0041] S9-1, the variable cross-section area 4 is symmetrical with the variable cross-section area 1. This area is the variable thickness area. The fabric thickness increases from 20mm to 26mm and then decreases to 25mm. This is achieved by adding and subtracting layers of warp and weft yarns, and by controlling the angle of the knitting tooling to better achieve contouring.

[0042] S9-2, continuing from the last weft of the previous area, the number of warp yarn layers is 26, and the warp yarn is evenly added. Each weft is woven with an outer warp layer, and a total of 8 layers are added. At this time, the warp yarn has 34 layers, and the fabric thickness reaches 26mm. Then the yarn is reduced. The outer warp yarn is reduced by one layer for the next weft, and the warp yarn has 33 layers, and the fabric thickness is 25mm. During the weaving process, the motor is used to make the bearing disk drive the shaft fan to rotate around the bearing to control the angle of the weaving tooling, and the clamp is used to make the fabric fit tightly to the core mold surface to ensure the curved surface of the fabric. At this time, the total length of the inner side of the fabric is 2268mm, and the next weaving area is entered;

[0043] S10, weaving of uniform cross-section zone 5:

[0044] S10-1, uniform cross-section area 5 is symmetrical with uniform cross-section area 1 and is the vertical area of ​​the landing gear. The thickness of this area does not change. The fabric thickness is 25mm and the length is 100mm. No yarn is added or subtracted. The fabric is made to fit the core mold better by controlling the tooling to achieve contouring.

[0045] S10-2: Based on the fabric thickness, introduce 33 layers of warp yarn and 34 layers of weft yarn. During the weaving process, use splints and hexagonal nuts to make the fabric close to the surface of the core mold to ensure the curvature of the fabric. Measure the fabric thickness every 20 mm to ensure that there is no significant deviation in the thickness. After weaving 100 mm, the total length of the inner side of the fabric reaches 2368 mm, completing the weaving of the landing gear preform.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention can solve the defects of the existing landing gear preforms that are woven in blocks and cannot be integrated into one shape, and achieve better size control and good mechanical properties. The three-dimensional woven composite material is used, which not only has the characteristics of large specific stiffness and high specific strength, but also has excellent anti-delamination and impact resistance, can realize lightweight design of the landing gear, and has good compression, bending and torsion resistance. The three-dimensional woven composite landing gear forming tooling includes a forming core mold, which can be integrated into one shape during the weaving process. The use of this tooling can better weave the ideal shape, which makes up for the defects of the previous block weaving of the landing gear and improves the overall performance of the composite landing gear. The tooling fixture can make the fabric fit tightly to the core mold during the weaving process, which solves the defects of the previous thickness control during weaving, and can better realize the variable thickness integrated molding of the leaf spring landing gear. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the assembly of the present invention;

[0049] Figure 2 It is a schematic diagram of the tooling of the present invention;

[0050] Figure 3 is a schematic diagram of a bearing of the present invention;

[0051] Figure 4 It is a schematic diagram of the shaft fan of the present invention;

[0052] Figure 5 It is a schematic diagram of the core mold of the present invention;

[0053] Figure 6 Schematic diagram of the clamp of the present invention;

[0054] Figure 7 It is a schematic diagram of the fabric of the present invention divided into regions;

[0055] Figure 8 It is the main flow chart of the present invention;

[0056] Figure 9 It is the assembly tool flow chart of the present invention;

[0057] Figure 10 It is a flow chart of weaving parameters of the present invention. DETAILED DESCRIPTION

[0058] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0059] Example 1

[0060] A three-dimensional woven composite material leaf spring landing gear preform copy molding tool comprises a tool frame 1, a core mold 2, five clamps 3, and five connecting rods 4.

[0061] The fixture frame 1 includes a bearing 5, ten shaft fans 6, and two pillars 7. The bearing 5 is equipped with two bearing discs 8, a connecting rod 2 12, two arched limit blocks 13, and a small motor 14. Each bearing disc has a positioning hole 9 at its center, and the positioning hole 9 has a diameter of 50 mm. The lower part of the bearing disc 8 has five symmetrically distributed "U"-shaped grooves 10, and each "U"-shaped groove has two limit holes 11, and the limit holes 11 have a diameter of 16 mm. The connecting rod 2 12 passes through the central positioning hole 9 of the bearing disc to connect the two bearing discs 8 horizontally. Each bearing disc 8 has an arched limit block 13 on the outside. The diameter of the connecting rod 2 12 matches the arc diameter of the positioning hole 9 and the arched limit block 13. The two arched limit blocks 13 are symmetrically distributed. The lower ends of the two arched limit blocks 13 are connected to the pillars 7 and are connected by welding. The shaft fan 6 is runway-shaped, with a length of 1200mm and an arc diameter of 16mm. There are two limit holes 15 at its upper end, which correspond to the size of the 'U'-shaped groove 10 of the bearing disk 8. There is a runway-shaped hole 16 at the lower end, which is 400mm long and 27mm away from the lower end of the shaft fan 6. The ten shaft fans 6 correspond to the 'U'-shaped grooves 10 on the two bearing disks 8 respectively. There are five shaft fans on each bearing disk, which are fixed by bolts passing through the 'U'-shaped grooves 10 and the limit holes 15 at the upper end of the shaft fans.

[0062] The core mold 2 has an arched symmetrical structure, with each side being composed of sixteen 'Z'-shaped core blocks 17 and a vertical core block 18 interlaced and combined, connected by a convex core block 19 in the middle, and the upper ends of the two vertical core blocks 18 are curved and fit into the lower ends of the 'Z'-shaped core blocks 17. Each core block is provided with a second positioning hole 20, and a connecting rod 1 4 passes through the second positioning hole 20 and the runway-shaped hole 16 on the shaft fan 6 to connect the core mold 2 to the tooling frame 1, and is fixed with a hexagonal nut 21 to complete the combination of the core mold 2 and the tooling frame 1; a small motor 14 is provided on the right side of the bearing 5, so that the ten shaft fans 6 drive the core mold 2 to rotate around the bearing 5, thereby realizing the rotation of the tooling;

[0063] The clamp 3 is composed of two clamps 22 and two small connecting rods 23. There are three positioning holes 24 at both ends of the clamps 22. The diameter of the positioning hole 24 is 16 mm. During the weaving process, one side of the clamp 22 is close to the core mold 2, and the other side is close to the fabric. The two small connecting rods 23 are connected through the positioning holes 24 and the two clamps 22 are clamped by the hexagonal nuts 21 to make the fabric fit the core mold 2 better and achieve the purpose of contour molding.

[0064] Example 2

[0065] A three-dimensional woven composite leaf spring landing gear structure preform includes nine regions: a uniform cross-section region 1 25, a variable cross-section region 1 26, a uniform cross-section region 2 27, a variable cross-section region 2 28, a uniform cross-section region 3 29, a variable cross-section region 3 30, a uniform cross-section region 4 31, a variable cross-section region 4 32, and a uniform cross-section region 5 33. The leaf spring has vertical sections on both sides and an arc section in the middle, forming a symmetrical structure. The fabric thickness varies in different regions, and variable thickness integrated weaving is adopted during the weaving process. The fabric region includes connecting warp yarns and weft yarns. The specific fabric parameters are set as follows:

[0066] The developed fabric has an arch height of 500mm and a span of 2000mm. The inner length of the entire leaf spring is 2368mm and the width is 185mm. The uniform cross-section area 25 is 100mm long, the variable cross-section area 26 is 20mm long, the uniform cross-section area 27 is 264mm long, the variable cross-section area 28 is 443mm long, and the uniform cross-section area 39 is 714mm long. They have a symmetrical structure. The variable cross-section area 30 is equal to the variable cross-section area 28, the uniform cross-section area 4 31 is equal to the uniform cross-section area 27, the variable cross-section area 4 32 is equal to the variable cross-section area 1 26, and the uniform cross-section area 5 33 is equal to the uniform cross-section area 1 25.

[0067] The warp yarn is TG800H-12K carbon fiber triple-ply, and the weft yarn is TG800H-12K single-ply;

[0068] The density of the warp yarns is 4 / cm, and the density of the weft yarns is 5 / cm;

[0069] Number of binding warp yarn rows n = fabric width × warp yarn density = 185 / 10 × 4 = 74 rows;

[0070] The volume content of fabric fiber is controlled at about 57%.

[0071] Example 3

[0072] A method for preparing a three-dimensional woven composite material leaf spring landing gear structure preform, wherein the weaving method comprises the following steps:

[0073] S1, tooling preparation, initial fabric arrangement, warp yarn hanging 74 rows, then weft insertion, according to the fabric thickness, calculate the number of weft insertion layers in each area;

[0074] S2, weaving of uniform cross-section area 25:

[0075] S2-1: In this area, the fabric is in a vertical state and the thickness does not change. The fabric thickness is measured to be 25 mm, and the number of warp and weft yarn layers introduced is calculated. At the same time, the weaving tooling is controlled during the weaving process to ensure that the fabric thickness is evenly distributed. The fabric thickness is measured every 20 mm during the weaving process to ensure that the thickness distribution is uniform.

[0076] S2-2, further, according to the thickness of the fabric, the number of warp yarn layers is 33 layers and the number of weft yarn layers is 34 layers. At the same time, during the weaving process, the four hexagonal nuts 21 in the clamp 3 are used to clamp the two clamps 22 to the fabric and the core mold 2, ensuring that they are close to the inside of the core mold to achieve the purpose of contour molding. After the inner length of the woven landing gear preform reaches 100 mm, it enters the next weaving area;

[0077] S3, weaving of variable cross-section area 26:

[0078] S3-1, this area is a variable thickness area, which is in the shape of a "corner". The inner length of the fabric is 20mm, and the fabric thickness increases from 25mm to 26mm and then decreases to 20mm. The change in fabric thickness is achieved by adding and subtracting layers of yarn during the weaving process, and the curved shape of the fabric is maintained by controlling the angle of the weaving tooling;

[0079] S3-2, further, when the total inner length of the fabric is 100mm, the yarn is added, the warp yarn is added one layer, becoming 34 layers, the weft yarn is 35 layers, and the fabric thickness reaches 26mm. Then the yarn is reduced, and one layer of outer warp yarn is reduced for each weft weaving, for a total of 8 layers. At this time, the warp yarn has 26 layers. At the same time, during the weaving process, the motor 14 is used to drive the shaft fan 6 to rotate around the bearing 5 to control the angle of the weaving tool so that the cloth fell is always parallel to the yarn direction. At the same time, the clamp 3 is used to make the fabric fit better with the core mold to achieve shape-matching. When the inner length of the preform reaches 120mm, it enters the next area for weaving;

[0080] S4, weaving of equal cross-section area 27:

[0081] S4-1, the fabric thickness in this area does not change. The fabric thickness is measured and is still 20mm. The design introduces the number of warp and weft yarn layers. The fabric in this area has a certain curvature. Therefore, tooling is used to ensure the curved surface of the fabric to achieve contour shaping. At the same time, the fabric thickness is measured every 20mm during the weaving process to ensure that there is no obvious deviation in the fabric thickness.

[0082] S4-2, further, the number of warp yarn layers is calculated to be 26 layers, and the number of weft yarn layers is calculated to be 27 layers. The motor 14 is used to make the bearing plate 8 drive the shaft fan 6 to rotate around the bearing 5 to control the angle of the weaving tool. The clamp 3 is used to make the fabric tightly fit the surface of the core mold 2 to ensure the curved surface of the fabric. 264 mm of weaving is completed. At this time, the total length of the inner side of the fabric is 384 mm, and the next weaving area is entered;

[0083] S5, weaving of variable cross-section area 28:

[0084] S5-1, the fabric thickness in this area increases evenly, the fabric has a certain curvature, and the thickness increases from 20mm to 37mm. This is achieved by uniformly adding layers of warp yarns. The angle of the weaving tooling is controlled during the weaving process to achieve better fabric shaping.

[0085] S5-2, further, the initial number of warp yarn layers of the fabric in this area is 26 layers, and a layer of warp yarn is added on the outside every 26 mm, for a total of 17 layers, so that the final fabric thickness reaches 37 mm. At this time, the number of warp yarn layers of the fabric increases to 48 layers. At the same time, during the weaving process, the bearing plate 8 is used to drive the shaft fan 6 to rotate around the bearing 5 to control the angle of the weaving tooling, and the clamp 3 is used to make the fabric tightly fit the surface of the core mold 2 to ensure the curved surface of the fabric. 443 mm of weaving is completed. At this time, the total length of the inner side of the fabric is 827 mm, and the next area of ​​weaving is entered;

[0086] S6, weaving of equal cross-section area 3 29:

[0087] S6-1, the top area of ​​the landing gear where it connects to the fuselage. The fabric thickness in this area is 37mm and does not vary. During the weaving process, the weaving tooling is controlled to maintain fabric curvature. The fabric thickness is measured every 20mm to ensure uniform thickness distribution.

[0088] S6-2, further, according to the thickness calculation, 48 layers of warp yarn and 49 layers of weft yarn are introduced, and no additional layers of warp and weft yarn are added. At the same time, during the weaving process, the splint 22 and the hexagonal nut 21 are used to make the fabric close to the surface of the core mold 2 to ensure the curvature of the fabric. After weaving 714 mm, the inner length of the fabric reaches 1541 mm, and the next weaving area is entered;

[0089] S7, weaving of variable cross-section area 30:

[0090] S7-1, the variable cross-section area 30 is symmetrical to the variable cross-section area 28. The arc length of this area is 443mm, and the fabric thickness is 37mm. The fabric thickness in this area is uniformly thinned from 37mm to 20mm. This is achieved by uniformly reducing the warp yarn layer. The angle of the weaving tooling is controlled to ensure the curved surface of the fabric. At the same time, the fabric thickness is measured every 20mm during the weaving process to ensure that its thickness is within a certain range without large deviations.

[0091] S7-2, further, in the initial stage, the number of warp yarn layers is 48 layers and the weft yarn layer is 49 layers. The number of outer warp yarn layers is reduced by one layer every 26 mm, a total of 17 layers are reduced, and 443 mm of weaving is completed. At this time, the fabric thickness is 20 mm, and the number of warp yarn layers is reduced to 26 layers. During the weaving process, the motor 14 is used to drive the shaft fan 6 to rotate around the bearing 5 to control the angle of the weaving tool. The cloth fell is always parallel to the yarn direction, and the hexagonal nut 21 is used to clamp the two clamps 22, so that the clamp 3 clamps the fabric and the core mold 2 to obtain a certain curved surface. At this time, the total length of the inner side of the fabric reaches 1984 mm, and the next weaving area is entered;

[0092] S8, weaving of equal cross-section area 4 31:

[0093] S8-1, the uniform cross-sectional area 4 31 and the uniform cross-sectional area 27 are symmetrically structured. This area is a uniform thickness area with a thickness of 20 mm. The thickness distribution is uniform and there is no significant variation. The thickness of the fabric is measured every 20 mm during the weaving process to ensure uniform thickness distribution. The angle of the weaving tooling is controlled to ensure the curved surface of the fabric.

[0094] S8-2, further, according to the thickness calculation, 26 layers of warp yarn and 27 layers of weft yarn need to be introduced. During the weaving process, the motor 14 is used to drive the shaft fan 6 to rotate around the bearing 5 to control the angle of the weaving tool. The splint 22 and the hexagonal nut 21 are used to make the fabric close to the surface of the core mold 2 to ensure the curved surface. The weaving process is 264 mm. At this time, the total length of the inner side of the fabric reaches 2248 mm, and the next weaving stage begins.

[0095] S9, weaving of variable cross-section area 4 32:

[0096] S9-1, the variable cross-section area 32 and the variable cross-section area 26 are symmetrical. This area is a variable thickness area. The fabric thickness increases from 20mm to 26mm and then decreases to 25mm. This is achieved by adding and subtracting layers of warp and weft yarns, and by controlling the angle of the knitting tooling to better achieve contouring.

[0097] S9-2, further, continuing the last weft of the previous area, the number of warp yarn layers is 26, and the warp yarn is evenly added. Each weft is woven with a layer of outer warp yarn, and a total of 8 layers are added. At this time, the warp yarn has 34 layers, and the fabric thickness reaches 26mm. Then the yarn is reduced. The next weft is reduced by one layer of outer warp yarn. The warp yarn has 33 layers, and the fabric thickness is 25mm. During the weaving process, the motor 14 is used to make the bearing disk 8 drive the shaft fan 6 to rotate around the bearing 5 to control the angle of the weaving tooling, and the fixture 3 is used to make the fabric fit tightly to the surface of the core mold 2 to ensure the curved surface of the fabric. At this time, the total length of the inner side of the fabric is 2268mm, and the next area is weaved;

[0098] S10, weaving of equal cross-section area 533:

[0099] S10-1, the uniform cross-section area 5 33 is symmetrical with the uniform cross-section area 1 25, which is the vertical area of ​​the landing gear. The thickness of this area does not change. The fabric thickness is 25 mm and the length is 100 mm. No yarn is added or subtracted. The fabric is made to fit the core mold 2 better by controlling the tooling to achieve contouring.

[0100] S10-2. Further, according to the thickness of the fabric, 33 layers of warp yarns and 34 layers of weft yarns are introduced. During the weaving process, the splints 22 and the hexagonal nuts 21 are used to make the fabric close to the surface of the core mold 2 to ensure the curvature of the fabric. The fabric thickness is measured every 20 mm to ensure that the thickness does not deviate significantly. After weaving 100 mm, the total length of the inner side of the fabric reaches 2368 mm, and the weaving of the landing gear preform is completed.

[0101] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0102] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A three-dimensional woven composite leaf spring landing gear preform profiling tool, characterized by: It includes a tooling frame (1), a core mold (2), five clamps (3), five connecting rods (4), The tooling frame (1) includes a bearing (5), ten shaft fans (6), and two pillars (7). The bearing (5) is equipped with two bearing discs (8), two connecting rods (12), two arched limit blocks (13), and a small motor (14). Each bearing disc (8) has a positioning hole (9) at the center. The lower part of the bearing disc (8) has five symmetrically distributed "U"-shaped grooves (10). Each "U"-shaped groove (10) has two limit holes (11). The connecting rod (12) passes through the central positioning hole (9) of the bearing disc (8) to connect the two bearing discs (8) horizontally. Then, each bearing disc (8) has an arched stopper (13) on the outside, and the lower ends of the two arched stopper blocks (13) are connected to the pillar (7) by welding. The upper end of the shaft fan (6) has two stopper holes (15) corresponding to the size of the 'U'-shaped groove (10) of the bearing disc (8), and the lower end has a runway-shaped hole (16). The ten shaft fans (6) correspond to the 'U'-shaped grooves (10) on the two bearing discs (8). There are five shaft fans (6) on each bearing disc, which are fixed by bolts passing through the 'U'-shaped groove (10) and the stopper holes (15) on the upper end of the shaft fan (6); The core mold (2) is an arched symmetrical structure, each side is composed of sixteen 'Z'-shaped core blocks (17) and a vertical core block (18) interlaced and combined, and is connected in the middle by a convex core block (19). The upper ends of the two vertical core blocks (18) are curved and fit into the lower ends of the 'Z'-shaped core blocks (17). Each vertical core block (18) is provided with a second positioning hole (20). A connecting rod (4) passes through the second positioning hole (20) and the runway-shaped hole (16) on the shaft fan (6) to connect the core mold (2) to the tooling frame (1), and is fixed with a hexagonal nut (21). A small motor (14) is provided on the right side of the bearing (5), so that the ten shaft fans (6) drive the core mold (2) to rotate around the bearing (5); The clamp (3) is composed of two clamps (22) and two small connecting rods (23). Positioning holes (24) are provided at both ends of the clamps (22). During weaving, one side of the clamps (22) is close to the core mold (2) and the other side is close to the fabric. The two small connecting rods (23) are connected by passing through the positioning holes (24) and the two clamps (22) are clamped by hexagonal nuts (21) to make the fabric fit the core mold (2) better.

2. The three-dimensional woven composite leaf spring landing gear preform profiling tooling according to claim 1, characterized in that: The diameter of the second connecting rod (12) matches the diameter of the arc of the positioning hole (9) and the arched limiting block (13), and the two arched limiting blocks (13) are symmetrically distributed.

3. The three-dimensional woven composite leaf spring landing gear preform profiling tooling according to claim 1, characterized in that: The shaft fan (6) is runway-shaped, with a length of 1200 mm and an arc diameter of 16 mm.

4. The three-dimensional woven composite leaf spring landing gear preform profiling tooling according to claim 1, characterized in that: The diameter of the limiting hole 1 (11) is 16 mm.

5. The three-dimensional woven composite leaf spring landing gear preform profiling tooling according to claim 1, characterized in that: The diameter of the positioning hole 1 (9) is 50 mm.

6. A three-dimensional woven composite leaf spring landing gear preform produced by using the three-dimensional woven composite leaf spring landing gear preform copying molding tool according to any one of claims 1 to 5, characterized in that: The three-dimensional woven composite leaf spring landing gear preform comprises nine regions, namely, a uniform cross-section region 1 (25), a variable cross-section region 1 (26), a uniform cross-section region 2 (27), a variable cross-section region 2 (28), a uniform cross-section region 3 (29), a variable cross-section region 3 (30), a uniform cross-section region 4 (31), a variable cross-section region 4 (32), and a uniform cross-section region 5 (33). The two sides of the leaf spring are vertical parts, and the middle is an arc part, presenting a symmetrical structure. The fabric thickness of different regions is different. Variable thickness integrated weaving is adopted during the weaving process. The fabric region includes connecting warp yarns and weft yarns. The specific parameters of the fabric are set as follows: The developed fabric has an arch height of 500mm and a span of 2000mm. The inner length of the entire leaf spring is 2368mm and the width is 185mm. The length of the uniform cross-section area 1 (25) is 100mm, the arc length of the variable cross-section area 1 (26) is 20mm, the length of the uniform cross-section area 2 (27) is 264mm, the length of the variable cross-section area 2 (28) is 443mm, and the length of the uniform cross-section area 3 (29) is 714mm. The structure is symmetrical. The length of the variable cross-section area 3 (30) is equal to that of the variable cross-section area 2 (28), the length of the uniform cross-section area 4 (31) is equal to that of the uniform cross-section area 2 (27), the length of the variable cross-section area 4 (32) is equal to that of the variable cross-section area 1 (26), and the length of the uniform cross-section area 5 (33) is equal to that of the uniform cross-section area 1 (25). The warp yarn is TG800H-12K carbon fiber triple-ply, and the weft yarn is TG800H-12K single-ply; The density of the warp yarns is 4 / cm, and the density of the weft yarns is 5 / cm; The number of binding warp yarn rows n = fabric width × warp yarn density = 185 / 10 × 4 = 74 rows; The volume content of fabric fiber is controlled at around 57%.

7. A method for preparing a three-dimensional woven composite leaf spring landing gear preform as claimed in claim 6, characterized in that: The following steps are involved: S1, tooling preparation, initial fabric arrangement, warp yarn hanging 74 rows, then weft insertion, according to the fabric thickness, calculate the number of weft insertion layers in each area; S2, weaving of uniform cross-section area 1 (25): S2-1: In this area, the fabric is in a vertical state and the thickness does not change. The fabric thickness is measured to be 25 mm, and the number of warp and weft yarn layers introduced is calculated. At the same time, the weaving tooling is controlled during the weaving process to ensure that the fabric thickness is evenly distributed. The fabric thickness is measured every 20 mm during the weaving process to ensure that the thickness distribution is uniform. S2-2, according to the thickness of the fabric, the number of warp yarn layers is 33 layers and the number of weft yarn layers is 34 layers. At the same time, during the weaving process, the four hexagonal nuts (21) in the clamp (3) are used to clamp the fabric and the core mold (2) with the two clamps (22) to ensure that they are close to the inside of the core mold to achieve the purpose of imitation molding. After the inner length of the woven landing gear preform reaches 100 mm, it enters the next area for weaving; S3, weaving of variable cross-section area 1 (26): S3-1, this area is a variable thickness area, which is in the shape of a "corner". The inner length of the fabric is 20mm, and the fabric thickness increases from 25mm to 26mm and then decreases to 20mm. The change in fabric thickness is achieved by adding and subtracting layers of yarn during the weaving process, and the curved shape of the fabric is maintained by controlling the angle of the weaving tooling; S3-2, when the total inner length of the fabric is 100 mm, the yarn is added, the warp yarn is added one layer, becoming 34 layers, the weft yarn is 35 layers, and the fabric thickness reaches 26 mm. Then the yarn is reduced, and one layer of outer warp yarn is reduced for each weft weaving, and a total of 8 layers are reduced. At this time, the warp yarn has 26 layers. At the same time, during the weaving process, the motor (14) is used to drive the shaft fan (6) to rotate around the bearing (5) to control the angle of the weaving tool so that the cloth mouth is always parallel to the yarn direction. At the same time, the clamp (3) is used to make the fabric fit better with the core mold to achieve imitation molding. When the inner length of the preform reaches 120 mm, it enters the next area for weaving; S4, weaving of the uniform cross-section area 2 (27): S4-1, the fabric thickness in this area does not change. The fabric thickness is measured and is still 20mm. The design introduces the number of warp and weft yarn layers. The fabric in this area has a certain curvature. Therefore, tooling is used to ensure the curved surface of the fabric to achieve contour shaping. At the same time, the fabric thickness is measured every 20mm during the weaving process to ensure that there is no obvious deviation in the fabric thickness. S4-2, calculate the number of warp yarn layers to be 26 layers and the number of weft yarn layers to be 27 layers, use the motor (14) to make the bearing plate (8) drive the shaft fan (6) to rotate around the bearing (5) to control the angle of the weaving tool, and use the clamp (3) to make the fabric fit tightly to the surface of the core mold (2) to ensure the curved surface of the fabric, weave 264mm, at this time the total length of the inner side of the fabric is 384mm, and enter the next area for weaving; S5, weaving of variable cross-section area 2 (28): S5-1, the fabric thickness in this area increases evenly, the fabric has a certain curvature, and the thickness increases from 20mm to 37mm. This is achieved by uniformly adding layers of warp yarns. The angle of the weaving tooling is controlled during the weaving process to achieve better fabric shaping. S5-2, the initial number of warp yarn layers of the fabric in this area is 26 layers, and a layer of warp yarn is added on the outside every 26 mm, with a total of 17 layers added, so that the final fabric thickness reaches 37 mm. At this time, the number of warp yarn layers of the fabric increases to 48 layers. At the same time, during the weaving process, the bearing plate (8) is used to drive the shaft fan (6) to rotate around the bearing (5) to control the angle of the weaving tool, and the clamp (3) is used to make the fabric fit tightly to the surface of the core mold (2) to ensure the curved surface of the fabric. The weaving process is 443 mm. At this time, the total length of the inner side of the fabric is 827 mm, and the next area weaving is entered; S6, weaving of uniform cross-section zone three (29): S6-1, the top area of ​​the landing gear where it connects to the fuselage. The fabric thickness in this area is 37mm and does not vary. During the weaving process, the weaving tooling is controlled to maintain fabric curvature. The fabric thickness is measured every 20mm to ensure uniform thickness distribution. S6-2, based on the thickness calculation, 48 layers of warp yarn and 49 layers of weft yarn are introduced, and no additional layers of warp and weft yarn are added. At the same time, during the weaving process, the splint (22) and the hexagonal nut (21) are used to make the fabric close to the surface of the core mold (2) to ensure the curvature of the fabric. After weaving 714 mm, the inner length of the fabric reaches 1541 mm, and the next area is weaved; S7, weaving of variable cross-section area three (30): S7-1, the variable cross-section area 3 (30) and the variable cross-section area 2 (28) are symmetrical structures. The arc length of this area is 443mm, and the fabric thickness is 37mm. The fabric thickness in this area is uniformly thinned from 37mm to 20mm. This is achieved by uniformly reducing the layers of warp yarns and controlling the angle of the weaving tooling to ensure the fabric bending surface. At the same time, the fabric thickness is measured every 20mm during the weaving process to ensure that its thickness is within a certain range; S7-2, in the initial stage, the number of warp yarn layers is 48 layers, and the number of weft yarn layers is 49 layers. The number of outer warp yarn layers is reduced by one layer every 26 mm, and a total of 17 layers are reduced. The weaving process is 443 mm. At this time, the fabric thickness is 20 mm, and the number of warp yarn layers is reduced to 26 layers. During the weaving process, the motor (14) is used to drive the shaft fan (6) to rotate around the bearing (5) to control the angle of the weaving tool. The cloth mouth is always parallel to the yarn direction, and the hexagonal nut (21) is used to clamp the two clamps (22) so that the clamp (3) clamps the fabric and the core mold (2) to obtain a certain curved surface. At this time, the total length of the inner side of the fabric reaches 1984 mm, and the next area is entered for weaving; S8, weaving of uniform cross-section zone 4 (31): S8-1, the equal cross-section area 4 (31) and the equal cross-section area 2 (27) are symmetrical structures. This area is an equal thickness area with a thickness of 20 mm. The thickness distribution is uniform and there is no obvious change. The thickness of the fabric is measured every 20 mm during the weaving process to ensure that the thickness distribution is uniform. The bending surface of the fabric is ensured by controlling the angle of the weaving tooling. S8-2, according to the thickness calculation, 26 layers of warp yarn and 27 layers of weft yarn need to be introduced. During the weaving process, the motor (14) is used to drive the shaft fan (6) to rotate around the bearing (5) to control the angle of the weaving tool. The splint (22) and the hexagonal nut (21) are used to make the fabric close to the surface of the core mold (2) to ensure the curved surface. The weaving process is 264 mm. At this time, the total length of the inner side of the fabric reaches 2248 mm, and the next stage of weaving is entered; S9, weaving of variable cross-section area four (32): S9-1, the variable cross-section area 4 (32) and the variable cross-section area 1 (26) are symmetrical structures. This area is a variable thickness area. The fabric thickness increases from 20mm to 26mm and then decreases to 25mm. This is achieved by adding and subtracting layers of warp and weft yarns, and by controlling the angle of the knitting tooling, better shaping is achieved; S9-2, continuing from the last weft of the previous area, the number of warp yarn layers is 26, and the warp yarn is evenly added. Each weft is woven with an outer warp yarn layer, and a total of 8 layers are added. At this time, the warp yarn has 34 layers, and the fabric thickness reaches 26 mm. Then the yarn is reduced. The outer warp yarn layer is reduced for the next weft, and the warp yarn has 33 layers. The fabric thickness is 25 mm. During the weaving process, the motor (14) is used to make the bearing disk (8) drive the shaft fan (6) to rotate around the bearing (5) to control the angle of the weaving tooling, and the fixture (3) is used to make the fabric fit tightly against the surface of the core mold (2) to ensure the curved surface of the fabric. At this time, the total length of the inner side of the fabric is 2268 mm, and the next area is entered for weaving; S10, weaving of uniform cross-section zone five (33): S10-1, the equal cross-section area five (33) and the equal cross-section area one (25) are symmetrically structured, and are the vertical areas of the landing gear. The thickness of this area does not change, the fabric thickness is 25 mm, the length is 100 mm, and no yarn is added or subtracted. The fabric is made to fit the core mold (2) better by controlling the tooling to achieve contour shaping; S10-2, further, according to the thickness of the fabric, 33 layers of warp yarn and 34 layers of weft yarn are introduced. During the weaving process, the splint (22) and the hexagonal nut (21) are used to make the fabric close to the surface of the core mold (2) to ensure the curvature of the fabric. The thickness of the fabric is measured every 20 mm to ensure that the thickness does not deviate significantly. After weaving 100 mm, the total length of the inner side of the fabric reaches 2368 mm, and the weaving of the landing gear preform is completed.

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