A sewing device and sewing method for small-size capped radome fabric

Abstract

The present invention relates to a sewing device for a small-sized capped antenna cover fabric, comprising a workbench, a mounting plate, an assembly core mold, and a mid-section sewing mold. The assembly core mold is composed of four sheet-shaped conical inner molds and is connected to the mounting plate via a flange. Through holes are evenly distributed along the center line of each sheet-shaped conical inner mold. The mounting plate is fixed to the assembly core mold at one end and to the workbench at the other end. The mid-section sewing mold is a sheet-shaped arc-shaped structure with a plurality of through holes evenly distributed thereon. Adjacent through holes along the length of the mid-section sewing mold are connected to form a wire groove. The middle portion of the mid-section sewing mold is also provided with a plurality of positioning holes matching the size of positioning pins along its length. The outer surface of the assembly core mold fits the inner surface of the preform fabric to be sewn, and the inner surface of the mid-section sewing mold fits the outer surface of the preform fabric to be sewn and is fixed via positioning pins. The present invention also includes a sewing method using the above-mentioned sewing device. The present invention can achieve high-quality sewing of fabrics with narrow internal spaces.

Description

Technical Field

[0001] The present invention belongs to the technical field of preform sewing, and in particular relates to a sewing device and a sewing method for a small-sized capped antenna cover fabric. Background Art

[0002] Composite material stitching technology refers to the use of stitching threads to combine multiple layers of fabric into a quasi-three-dimensional fabric, that is, introducing reinforcing fibers in the thickness direction of the preform fabric to connect several separate pieces of fabric into an integral structure. It is a composite material preform preparation technology that is widely used in military and civilian fields.

[0003] Researchers have conducted extensive research on methods for preparing radome preform fabrics. The patent, entitled "Method for Preparing a Conical High-Performance Fiber Radome Preform Fabric" (Patent No. CN201910602618.8), provides a method for forming a conical radome preform fabric. Positioning holes are drilled in the mold, and positioning pins are manually inserted to locate the stitching points. After positioning, the surface mold must be removed, and then S-shaped stitching is performed. The entire process is relatively complex, and the S-shaped stitching method is difficult to meet the requirements of sewing and forming small-sized capping fabrics with confined interior spaces. The patent, entitled "Stitching and Weaving of Fiber Fabrics for Radomes and Specialized Stitching Die" (Patent No. CN201510413474.3), provides a stitching die and method for sewing rotary conical radome fabrics. Long stitching holes are drilled in the mold surface for stitching. The position of the stitching trajectory points is difficult to control, and stitching uniformity and quality are difficult to ensure. In summary, existing stitching technologies are difficult to meet the requirements of high-quality stitching and forming small-sized capping radome fabrics with confined interior spaces. Summary of the Invention

[0004] In order to solve the technical problems existing in the known technology, the present invention provides a sewing device and a sewing method for a small-sized capped antenna cover fabric. The present invention effectively solves the problems of complex operation during the preparation and molding process of such fabrics and difficulty in sewing due to the small inner cavity; and realizes the control of the sewing points and the control of the uniformity of the fabric sewing process.

[0005] The present invention includes the following technical solutions:

[0006] A device for sewing small-sized capped antenna cover fabrics, comprising a workbench, a mounting plate, an assembly core mold and a middle-section sewing mold; the assembly core mold is composed of four sheet-like conical inner molds and is connected to the mounting plate through a flange, and through holes are evenly distributed on the center line of each sheet-like conical inner mold; one end of the mounting plate is fixed with the assembly core mold, and the other end is fixed with the workbench; the middle-section sewing mold is a sheet-like arc structure and has a plurality of through holes evenly distributed, and adjacent through holes along the length direction of the middle-section sewing mold are connected to form a wire groove; the middle part of the middle-section sewing mold is also provided with a plurality of positioning holes matching the size of the positioning pins along its length direction; the outer surface of the assembly core mold fits the inner surface of the preform fabric to be sewn, and the inner surface of the middle-section sewing mold fits the outer surface of the preform fabric to be sewn and is fixed by the positioning pins.

[0007] Furthermore, the mounting plate includes a flange mounting plate and a workbench mounting plate; a φ64 light hole is provided at one end of the flange mounting plate as a core mold mounting hole, and mounting holes that match the flange are evenly distributed around the core mold mounting hole, and the other end is provided with a mounting hole for connecting to the workbench mounting plate.

[0008] Furthermore, the thickness of the middle section sewing mold is 5 mm, and the middle section sewing mold cooperates with the positioning needle and the sewing needle to position and sew the preform fabric.

[0009] Furthermore, the sheet-like conical inner mold is made by 3D printing, has a thickness of 5 mm, and has several φ2 through holes arranged longitudinally at an equal distance of 10 mm from the bottom to the top at its center; two cylindrical countersunk holes for M5 hexagonal countersunk studs are evenly distributed at its bottom installation position, which can be independently installed or removed on the flange.

[0010] A method for sewing a small-sized capped radome fabric, using the above-mentioned sewing device, comprises the following steps: S1, placing the sewing device: placing the installed sewing device in a workspace; S2, layer design and raw material preparation: dividing the preform fabric of the small-sized capped radome of a rotating body to be prepared into four equal parts in space, and flattening it into a plurality of unit layer layers and cone top difference layers according to its thickness and the thickness of the quartz cloth, and cutting the unfolded unit layer layers and cone top difference layers on the quartz cloth; S3, layer laying: laying the prepared unit layer layers and cone top difference layers in sequence on a sewing mold, and arranging a plurality of cone top difference layers between two adjacent unit layer layers; S4, sewing: sewing the laid rotating body fabric in sequence on the sewing mold.

[0011] Furthermore, the S2 includes S2-1 to prepare a preform fabric for a semi-conical unit layer ply and S2-2 to prepare a preform fabric for a cone top difference layer; the preform fabric for a small-sized capping antenna cover of a rotating body to be prepared is cut on the cutting surface along the two cone normals of the front view, spatially divided, and the divided fabric surface is unfolded to obtain a half-piece unit layer ply and a cone top difference layer. In order to improve the continuity and stability of the internal interlayer structure of the fabric, the unfolded half-piece unit layer ply is spliced ​​every two to obtain a semi-conical unit layer ply. Since the preform fabric for a small-sized capping antenna cover of a rotating body is used on high-speed flying satellites, it generates a large amount of heat due to friction with the air during high-speed flight, and the temperature it withstands is high. Therefore, it is necessary to set a cone top difference layer to increase the thickness of the cone top and improve the thermal corrosion resistance of the small-sized capping antenna cover fabric.

[0012] Furthermore, the S3 also includes S3-1, which is a pair of semi-conical unit plies laid in a clockwise direction of 45 degrees, so that the joints between two adjacent pair of semi-conical unit plies are staggered, thereby ensuring the structural stability of the preform fabric and avoiding stratification; S3-2 ply fixing, after laying a layer of pair of semi-conical unit plies, the fabric is tightly wound spirally from the top of the cone downward with nylon thread, and the nylon thread at the top and bottom of the cone is fixed with short nails. When laying the next layer of unit plies, the short nail at the top of the cone is pulled out first, and while pressing the fabric, the next unit ply is laid while rotating 45 degrees clockwise compared to the previous unit ply. When laying to the short nail at the bottom of the cone of the previous unit ply, the fabric is wrapped with nylon thread again, and the short nail at the top of the cone is nailed in, and then the short nail at the bottom of the cone of the previous unit ply is pulled out, and it is nailed together with the next unit layer at the bottom of the cone, and then laid back and forth in sequence.

[0013] Furthermore, the S4 includes S4-1 cone stitching, S4-2 solid cone top stitching, and S4-3 cone top circle stitching, wherein the S4-1 cone stitching is performed by stitching the cone stitching area by a middle stitching mold in cooperation with a stitching device, and the small-size capped antenna cover preform fabric of the rotating body after the laying is divided into 4 parts along the circumferential direction, and then the improved lock stitching method is used to perform four-step cone stitching; wherein the S4-2 solid cone top stitching adopts an N-shaped path stitching method to perform through stitching on the solid cone top stitching area; wherein the S4-3 cone top circle stitching is performed by stitching the cone top circle stitching area from the cone top to the inner cavity of the cone bottom, and also adopts an improved lock stitching method, and its stitching principle is the same as the stitching principle of the cone cavity area; the cone top circle is completely filled with a number of equilateral triangles, and the stitches are set at the vertices of the triangles, and the cone top circle stitching is completed according to the stitching stitches.

[0014] Furthermore, the four-step cone sewing in S4-1 is specifically as follows: the first step of cone sewing is to place the middle section sewing mold close to the outer surface of the preform fabric and use a number of positioning needles to pass through the positioning holes on the surface of the middle section sewing mold and penetrate the preform fabric and pass through the center line of the sheet-shaped cone inner mold. After the through hole is positioned, the sheet-like conical inner mold corresponding to the middle-section sewing mold is removed, and the improved lock-type sewing method is used for sewing according to the through hole on the surface of the middle-section sewing mold; before sewing, a prefabricated hole is punched at the point to be sewn with a prefabricated hole needle. After withdrawing the prefabricated hole needle, the sewing thread is inserted into the threading hole at the needle tip of the machine needle, passed through the prefabricated fabric, and a thread loop is left in its inner cavity. The thread loop is hooked out with a slender hook and passed through the bottom line, and then the machine needle is pulled out to lock the thread loop in the inner cavity of the prefabricated fabric, completing the sewing at one point, and sewing at the next sewing point according to this step to perform the first step of cone sewing; after completing the sewing, the middle-section sewing mold is removed, and the sheet-like conical inner mold at this position is installed to complete the first step of cone sewing; in the second step, the middle-section sewing mold is rotated 90 degrees clockwise along the circumference of the fabric compared to the position of the middle-section sewing mold in the first step, and the positioning needle is inserted again for positioning, and the second step of cone sewing is completed according to the steps in the first step; the cone sewing of the third and fourth steps is completed in sequence according to this step.

[0015] Since the inner cavity of the fabric of the small-sized capped radome preform of the rotating body is small, conventional through-stitching cannot be performed. Therefore, an improved lock-stitching method is adopted. This method reduces the wear and breakage of the suture line, improves the interlayer strength of the fabric, and reduces in-plane fiber damage.

[0016] Furthermore, the top of the cone (i.e., the cone at the top position of the middle sewing mold) is connected to the top part of the cone (the top part of the cover fabric), that is, the solid position above that cannot be sewn by the middle sewing mold is called a solid cone top. The N-shaped path sewing method in S4-2 is specifically as follows: the solid cone top is divided into a number of circumferential sewing positions every 3mm in the upward direction of the Z axis. In the first step of circumferential sewing, the sewing needle penetrates the solid cone top and sews back from the other side in parallel at an equal distance of 3mm, and sews in sequence along the horizontal direction to complete the first step of circumferential sewing; in the second step of circumferential sewing, the second step of circumferential sewing position is found along the direction of the cone top, that is, along the Z axis at an equal distance of 3mm. The sewing point is deflected 45 degrees clockwise compared to the sewing point of the previous step. This deflection of the sewing angle effectively improves the structural strength of the fabric and reduces the risk of delamination. The sewing operation of the first step is repeated to complete the second step of circumferential sewing; the second step of circumferential sewing is repeated until the solid cone top sewing part is sewn upward.

[0017] The present invention has the following advantages and positive effects:

[0018] 1. The present invention aims at the structural characteristics of the small-sized capped radome fabric and proposes a forming method of partitioned sewing and coupling of multiple sewing methods, which meets the high-quality sewing forming requirements of the small-sized capped radome fabric with a narrow internal space.

[0019] 2. The present invention adopts a new improved lock-type stitching method to stitch the cavity area as a whole. Prefabricated holes are first punched, and the bottom line is passed outside. This overcomes the problem of narrow internal space of the fabric and difficulty in stitching. It also reduces the wear and breakage of the stitching line, improves the interlayer strength of the fabric, reduces in-plane fiber damage, and has a relatively high damage tolerance.

[0020] 3. The present invention adopts an N-shaped path suturing method and an improved lock-type suturing method to suturing the top solid area radially and axially, which greatly improves the volume density of the large curvature top and improves the load-bearing performance.

[0021] 4. The present invention sets the suture track through the positioning holes and wire grooves on the middle suture mold, thereby improving the accuracy of the suture point spacing and improving the suture quality.

[0022] 5. The combined core mold used in the present invention is made by resin-based 3D printing technology, which has low manufacturing cost. Its mold surface has the same curved surface as the fabric covering surface, and after the covering is completed, the fabric is fixed with positioning pins around the fabric through the φ2 through hole at the center of the sheet core mold to effectively prevent relative slippage between the covering surfaces during stitching and ensure the stability of the internal structure of the preform fabric.

[0023] 6. The interface positions of the present invention are cross-distributed during layer laying. At the same time, the top variable thickness area adopts a uniform intercalation method to set the cone top difference layer, which ensures the overall structural strength of the preform fabric and improves the thermal corrosion resistance of the fabric.

[0024] 7. The present invention uses spiral wires to bundle and reinforce the unit layers during ply laying, thereby ensuring the accuracy of the ply positions and greatly improving the interlayer density of the preform fabric.

[0025] 8. When the detachable assembly core mold used in the present invention is used to sew the preform fabric of a small-sized capped antenna cover, the detachable structure increases the sew space, making the sew process easier and reducing the limitation of the small inner cavity of the small-sized capped antenna cover fabric on the sew process; at the same time, the core molds at the corresponding sew positions are removed in turn so that the fabric will not be deformed due to the sew force during sew. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the suturing device of the present invention;

[0027] Figure 2 is an exploded view of the installation of the suturing device of the present invention;

[0028] Figure 3 It is a schematic diagram of the overall structure of the combined core mold of the present invention;

[0029] Figure 4 It is a schematic diagram of the structure of the middle section stitching mold of the present invention;

[0030] Figure 5 yes Figure 4 A magnified schematic diagram of the AA structure;

[0031] Figure 6 Schematic diagram of the sewing area of ​​the preform fabric in the present invention;

[0032] Figure 7 It is a three-dimensional diagram of the combination state of the middle-section stitching mold and the preform fabric;

[0033] Figure 8 It is a top view of the middle section stitching mold and the preform fabric in combination;

[0034] Figure 9 It is a flowchart of cone stitching of preform fabric;

[0035] Figure 10 It is a flow chart of solid cone top circle stitching of preform fabric;

[0036] Figure 11 1. It is a schematic diagram of the cone-top circle sewing stitch of the preform fabric;

[0037] Figure 12 It is a flow chart of sewing the cone top circle of the preform fabric;

[0038] Figure 13 is a schematic diagram of the layup of the preform fabric;

[0039] Figure 14 yes Figure 13 A magnified schematic diagram of the BB structure;

[0040] Figure 15 It is a flow chart of the lay-up design and production of prefabricated fabrics;

[0041] Figure 16 It is a schematic diagram of ply fixing of the present invention;

[0042] In the figure, 1- positioning needle; 1.1- first positioning needle; 1.2- second positioning needle; 1.3- third positioning needle; 2- middle section suture mold; 2.1- first positioning hole; 2.2- second positioning hole; 2.3- third positioning hole; 2.4- left suture path; 2.5- right suture path;

[0043] 3-preform fabric; 3.1-cone stitching area; 3.2-solid cone top stitching area; 3.3-cone top circular stitching area;

[0044] 4 - Assembly core mold; 4.1 - First core module; 4.2 - Second core module; 4.3 - Third core module; 4.4 - Fourth core module; 5 - Flange; 6 - Flange mounting plate; 7 - Workbench mounting plate; 8 - Workbench;

[0045] 9-prefabricated hole needle; 10-suture needle; 11-suture thread; 12-bottom thread; 13-slender hook needle; 14-short nail; 15-nylon thread; 16-top semi-conical unit layer laying; 17-cone top difference layer; 18-cutting surface. DETAILED DESCRIPTION

[0046] In order to further disclose the content, features and effects of the present invention, the following examples are given and described in detail with reference to the accompanying drawings.

[0047] Example: See attached Figure 1-5 A sewing device for a small-sized capped antenna cover fabric includes a workbench 8, a mounting plate, a combination core mold 4, and a middle-section sewing mold 2; the thickness of the middle-section sewing mold 2 is 5 mm, and the middle-section sewing mold 2 cooperates with a positioning needle 1 and a sewing needle 10 to position and sew the preform fabric 3.

[0048] The assembly core mold 4 is composed of four sheet-shaped conical inner molds and is connected to the mounting plate through a flange 5. Through holes are evenly distributed on the center line of each sheet-shaped conical inner mold; one end of the mounting plate is fixed with the assembly core mold 4, and the other end is fixed with the workbench 8; the middle section stitching mold 2 is a sheet-shaped arc structure and has a plurality of through holes evenly distributed thereon. The adjacent through holes along the length direction of the middle section stitching mold 2 are connected to form a wire groove; the middle part of the middle section stitching mold 2 is also provided with a plurality of positioning holes (in this example, as shown in FIG. 1 ) that match the size of the positioning pin 1 along its length direction. Figure 5 The first positioning hole 2.1, the second positioning hole 2.2, and the third positioning hole 2.3 are shown respectively; the outer surface of the assembly core mold 4 fits the inner surface of the preform fabric 3 to be sewn, and the inner surface of the middle section sewing mold 2 fits the outer surface of the preform fabric 3 to be sewn and is fixed by the positioning needle 1.

[0049] The mounting plate includes a flange mounting plate 6 and a workbench mounting plate 7; a light hole is provided at one end of the flange mounting plate 6 as a core mold mounting hole, and mounting holes for matching with the flange 5 are evenly distributed around the core mold mounting hole (in this case, 12 φ7 light holes are evenly distributed at a radius of 41.5 from the center of the core mold mounting hole for matching with the flange 5), and two φ8.55 mounting holes for connecting to the workbench mounting plate 7 are evenly distributed at the other end. Four φ8.55 light holes are distributed on one side of the workbench mounting plate 7 to match with the M10 threaded holes on the workbench 8, and two M10 threaded holes are evenly distributed in the horizontal direction on the other side for matching with the flange mounting plate 6. The mounting hole diameter of the flange 5 is 46, and eight M5 threaded holes are evenly distributed at a radius of 26.5 from the center of the mounting hole for connecting with the assembly core mold 4, and eight M6 threaded holes are evenly distributed at a radius of 41.5 from the center of the mounting hole for connecting with the flange mounting plate 6.

[0050] The sheet-like conical inner mold is made by 3D printing, such as Figure 3 As shown, they are the first core module 4.1, the second core module 4.2, the third core module 4.3, and the fourth core module 4.4; they are 5 mm thick and have a number of through holes arranged longitudinally at an equal distance of 10 mm from the bottom to the top at the center position, as well as two cylindrical countersunk holes for M5 hexagonal countersunk studs evenly distributed at the bottom mounting position, which can be independently installed or removed on the flange 5.

[0051] See attached Figure 1-16 A method for sewing a small-sized capped radome fabric, using the above-mentioned sewing device, comprises the following steps:

[0052] S1. Place the sewing device: Place the installed sewing device in the workspace; the outer conical surface of the assembly core mold 4 is the same as the inner cavity of the small-sized capped antenna cover fabric, which is mainly used to support the fabric covering surface and shape it into a rotating body preform fabric 3 during the laying process.

[0053] S2. Layer design and raw material preparation: Figure 12 As shown, the preform fabric 3 of the small-sized capped radome of the rotating body to be prepared is spatially divided into four equal parts, and flattened into several unit layer plies and cone top difference layers 17 according to its thickness and the thickness of the quartz cloth, and the unfolded unit layer plies and cone top difference layers 17 are cut on the quartz cloth; the S2 includes S2-1 to make the preform fabric top semi-conical unit layer plies 16 and S2-2 to make the preform fabric cone top difference layer 17; the preform fabric 3 of the small-sized capped radome of the rotating body to be prepared is cut on the cutting surface 18 along the two cone normals of the front view, divided in space and the divided fabric surface is unfolded to obtain half-piece unit layer plies and cone top difference layers 17. In order to improve the continuity and stability of the internal interlayer structure of the fabric, the unfolded half-piece unit layer plies are spliced ​​every two to obtain top semi-conical unit layer plies 16. Since the preform fabric 3 of the rotating small-sized capped antenna cover is used on a high-speed flying satellite, a large amount of heat is generated due to friction with the air during high-speed flight, and the temperature it withstands is high. Therefore, it is necessary to set a cone top difference layer 17 to increase the thickness of the cone top and improve the thermal corrosion resistance of the small-sized capped antenna cover fabric.

[0054] S3, laying: The prepared unit layer plies and cone top difference layers 17 are laid out in sequence on the sewing mold, with a plurality of cone top difference layers 17 being arranged between two adjacent unit layer plies; the S3 also includes S3-1 laying the top semi-conical unit plies 16 in a clockwise direction of 45 degrees, so that the joints between the two adjacent top semi-conical unit plies 16 are staggered, thereby ensuring the structural stability of the preform fabric 3 and avoiding delamination; S3-2 fixing the plies, after laying a layer of top semi-conical unit plies 16, using nylon thread 15 to spirally wrap the fabric tightly from the cone top downwards, such as Figure 15As shown, the nylon line 15 at the top and bottom of the cone is fixed with short nails 14. When laying the next unit layer, the short nail 14 at the top of the cone is pulled out first. While pressing the fabric, the next unit layer is laid 45 degrees clockwise compared to the previous unit layer. When it is laid to the short nail 14 at the bottom of the cone of the previous unit layer, the nylon line 15 is wrapped around the fabric and the short nail 14 at the top of the cone is nailed in. Then the short nail 14 at the bottom of the cone of the previous unit layer is pulled out and nailed together with the next unit layer at the bottom of the cone. The layers are laid back and forth in sequence.

[0055] S4, sewing: The laid rotating fabric is sewn sequentially on the sewing mold. The S4 includes S4-1 cone sewing, S4-2 solid cone top sewing, S4-3 cone top circle sewing, wherein S4-1 cone sewing is performed by the middle sewing mold 2 cooperating with the sewing device to sew the cone sewing area 3.1, such as Figure 4 In the process, first sew the left side sew path 2.4 of the middle section sew mold 2 toward the center of the middle section sew mold 2 according to the circular arrow. After sewed to the center of the middle section sew mold 2, the left side sew path 2.4 is sewed. Then sew the right side sew path 2.5. Similar to the left side sew path 2.4, sew the right side sew path 2.5 of the middle section sew mold 2 toward the center of the middle section sew mold 2 according to the circular arrow. Figure 9 As shown in 3.1.1-3.1.6, the preform fabric 3 of the small-sized capping antenna cover of the rotating body after the laying is divided into 4 parts in the circumferential direction, and then the improved lock-stitching method is used to perform four-step cone stitching; the four-step cone stitching in S4-1 is specifically as follows: the first step of cone stitching is to place the middle section stitching mold 2 close to the outer surface of the preform fabric 3 and use a number of positioning needles 1 to pass through the positioning holes on the surface of the middle section stitching mold 2 to penetrate the preform fabric 3 and complete the positioning through the through hole at the center line of the sheet-shaped conical inner mold, then remove the sheet-shaped conical inner mold corresponding to the middle section stitching mold 2, and use the improved lock-stitching method to stitch according to the through hole on the surface of the middle section stitching mold 2; before stitching, use the prefabricated hole needle 9 to punch the prefabricated hole at the point to be stitched, and exit the prefabricated hole needle 9. After the hole-making needle 9, the suture thread 11 is inserted into the threading hole at the needle tip of the machine needle, passed through the preform fabric 3, and a thread loop is left in its inner cavity. The thread loop is hooked out with a slender crochet needle 13 and inserted into the bottom line 12, and then the machine needle is pulled out to lock the thread loop in the inner cavity of the preform fabric 3, completing the suture at one point, and suture at the next suture point according to this step to perform the first step of cone suture; after completing the suture, the middle section suture mold 2 is removed, and the sheet-shaped conical inner mold at this position is installed to complete the first step of cone suture; in the second step, the middle section suture mold 2 is rotated 90 degrees clockwise along the circumference of the fabric compared to the position of the middle section suture mold 2 in the first step, and the positioning needle 1 is inserted again for positioning, and the second step of cone suture is completed according to the steps in the first step; the cone sutures of the third and fourth steps are completed in sequence according to this step.

[0056] The S4-2 solid cone top suture adopts the N-shaped path suture method to suture the solid cone top suture area 3.2 through the suture. Figure 10 As shown in 3.2.1-3.2.6; the top of the cone (i.e. the cone at the top position of the middle sewing mold) is connected to the top of the cone (the top part of the cover fabric), that is, the upper solid position that cannot be sewn by the middle sewing mold 2 is called the solid cone top. The N-shaped path sewing method in S4-2 is specifically: the solid cone top is divided upward in equal intervals of 3mm along the Z axis. Figure 10 As shown in the six circumferential suture positions 3.2.1-3.2.6, in the first circumferential suture of 3.2.1, the suture needle 10 penetrates the solid cone top and sews back from the other side in parallel at an equal distance of 3mm, and sews in sequence along the horizontal direction to complete the first circumferential suture; in the second circumferential suture of 3.2.2, the second circumferential suture position is found along the direction of the cone top, that is, along the Z axis at an equal distance of 3mm. The suture point is deflected 45 degrees clockwise compared with the suture point of the previous suture. This deflection of the suture angle effectively improves the structural strength of the fabric and reduces the risk of delamination. The suture operation of the first step is repeated to complete the second circumferential suture; the second circumferential suture is repeated until the solid cone top suture part of the remaining four steps is completed by sewing upward.

[0057] Among them, S4-3 cone top circle suture is to suture the cone top circle suture area 3.3 from the cone top to the cone bottom inner cavity, such as Figure 11 As shown, the improved lock suture method is also used, and its suture principle is the same as that of the cone cavity area suture; the cone top circle is completely filled with several regular triangles, the stitches are set at the vertices of the triangles, and the cone top circle is sutured according to the stitches. Figure 11 Take stitch 3.3.1 as an example to perform cone-top circle modified lock stitch. The specific steps are as follows: Figure 12 As shown in 3.3.1.1 to 3.3.1.6, since the small cover preform has completed the S4-1 cone suture and the S4-2 solid cone top suture at this time, the small cover at this time has a certain rigidity, and in order to avoid the interference of the assembly core mold 4 on the prefabricated hole needle 9 and the suture needle 10 during the cone top circle suture process, it can only use the first core module 4.1 for support when performing the cone top circle suture, and the prefabricated hole needle 9 and the suture needle 10 are sutured in the other three inner cavity areas where the core mold is not installed. In addition, in order to prevent the small cover from rotating during the cone top circle suture process, an outer covering middle section suture mold 2 is used in conjunction with the positioning needle 1 to limit the freedom of rotation of the small cover, so that the cone top circle suture process can proceed smoothly, as shown in FIG. Figure 12 At this time, the 3.3.1 stitch cone top circle suture only retains the first core module 4.1 to support the small cover and cooperate with the first positioning needle 1.1, the second positioning needle 1.2, and the third positioning needle 1.3 to limit the rotational freedom of the small cover during the suture process, such as Figure 12As shown in 3.3.1.1-3.3.1.6, remove the other three core modules except the first core module 4.1, and cover the corresponding area of ​​the first core module 4.1 with the middle section sewing mold 2, and use the positioning needle 1 to penetrate the small cover and pass through the through hole at the center of the first core module 4.1 to complete the positioning. Figure 11 A prefabricated hole is punched at the point to be sutured in the stitch 3.3.1, and then a machine needle is used to insert the suture thread 11 through the fabric at the prefabricated hole, leaving a thread loop in the inner cavity, and then a slender crochet hook 13 is used to hook out the thread loop and insert the bottom thread 12, and then the suture needle 10 withdraws from the prefabricated hole and locks the thread loop to complete the suturing at one point. Afterwards, according to this method, the stitches are completed in sequence. It should be noted that during the stitching process, when the inner cavity area corresponding to the remaining first core module 4.1 needs to be stitched, the prefabricated hole needle 9, the stitching needle 10 and the first core module 4.1 will interfere with each other. When this happens, the core mold is reinstalled in the stitched inner cavity area. However, in order to avoid new interference, only one core module is installed. At the same time, the first core module 4.1 and the corresponding middle stitching mold 2 and positioning needle 1 that interfere with the prefabricated hole needle 9 and the stitching needle 10 are removed. The middle stitching mold 2 and the positioning needle 1 are installed in the corresponding position of the new core module and repositioned. The remaining inner cavity area continues to be stitched with the cone top circle until all the stitching parts of the cone top circle stitching area 3.3 are stitched. This process is repeated until the stitching of the remaining stitching parts 3.3.2 and 3.3.3 is completed.

[0058] Since the inner cavity of the fabric of the small-sized capped radome preform of the rotating body is small, conventional through-stitching cannot be performed. Therefore, an improved lock-stitching method is adopted. This method reduces the wear and breakage of the suture line, improves the interlayer strength of the fabric, and reduces in-plane fiber damage.

[0059] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the aforementioned specific embodiments. The aforementioned specific embodiments are merely illustrative and not restrictive. Persons skilled in the art, informed by the present invention, may devise various embodiments without departing from the spirit of the present invention and the scope of protection of the claims. All such embodiments fall within the scope of protection of the present invention.

Claims

1. A method for sewing a small-sized capping antenna cover fabric, using a sewing device for a small-sized capping antenna cover fabric, the sewing device comprising a workbench, a mounting plate, a combined core mold and a middle-section sewing mold; the combined core mold is composed of four sheet-shaped conical inner molds and is connected to the mounting plate through a flange, and through holes are evenly distributed on the center line of each sheet-shaped conical inner mold; one end of the mounting plate is fixed with the combined core mold, and the other end is fixed with the workbench; the middle-section sewing mold is a sheet-shaped arc structure and has a plurality of through holes evenly distributed, and the adjacent through holes along the length direction of the middle-section sewing mold are connected to form a wire groove; the middle part of the middle-section sewing mold is also provided with a plurality of positioning holes matching the size of the positioning pins along its length direction; the outer surface of the combined core mold fits the inner surface of the preform fabric to be sewn, and the inner surface of the middle-section sewing mold fits the outer surface of the preform fabric to be sewn and is fixed by the positioning pin, characterized in that The sewing method comprises the following steps: S1, placing the sewing device: placing the installed sewing device in the work space; S2, layer design and raw material preparation: dividing the preform fabric of the small-sized capped radome of the rotating body to be prepared into four parts in space, and flattening it into several unit layer layers and cone top difference layers according to its thickness and the thickness of the quartz cloth, and cutting the unfolded unit layer layers and cone top difference layers on the quartz cloth; S3, layer laying: laying the prepared unit layer layers and cone top difference layers on the assembly core mold in sequence, and setting several cone top difference layers between two adjacent unit layer layers. Top difference layer; S4, sewing: sewing the laid rotational fabric on the assembly core mold in sequence; the S2 includes S2-1 making the preform fabric top semi-conical unit layer ply and S2-2 making the preform fabric cone top difference layer; the rotational small-size capping antenna cover preform fabric to be prepared is cut on the cutting surface along the two cone normals of the front view, divided in space and the divided fabric surface is unfolded to obtain half-piece unit layer ply and cone top difference layer, and the unfolded half-piece unit layer ply is spliced ​​every two to obtain the top semi-conical unit layer ply.

2. The method for sewing a small-sized capped radome fabric according to claim 1, characterized in that: The S3 also includes S3-1, which is a pair of semi-conical unit plies that are laid in a clockwise manner at an angle of 45 degrees, so that the joints between two adjacent pair of semi-conical unit plies are staggered; S3-2, the plies are fixed. After laying one layer of semi-conical unit plies, the fabric is tightly wound spirally from the top of the cone downward with nylon thread, and the nylon thread at the top and bottom of the cone is fixed with short nails. When laying the next layer of unit plies, the short nail at the top of the cone is first pulled out, and while pressing the fabric, the next unit ply is laid while rotating 45 degrees clockwise compared to the previous unit ply. When laying the fabric to the short nail at the bottom of the cone of the previous unit ply, the fabric is wrapped with nylon thread again, and the short nail at the top of the cone is nailed in. Then the short nail at the bottom of the cone of the previous unit ply is pulled out, and it is nailed together with the next unit ply at the bottom of the cone, and the ply is laid back and forth in sequence.

3. The method for sewing a small-sized capped radome fabric according to claim 1, characterized in that: The S4 includes S4-1 cone stitching, S4-2 solid cone top stitching, and S4-3 cone top circle stitching, wherein the S4-1 cone stitching is stitched by a middle section stitching mold in conjunction with a combined core mold, and the preform fabric of the small-sized capped antenna cover of the rotating body after the laying is divided into 4 parts along the circumferential direction, and then the four-step cone stitching is performed using an improved lock stitching method; wherein the S4-2 solid cone top stitching is performed through stitching using an N-shaped path stitching method; wherein the S4-3 cone top circle stitching is stitched from the cone top to the inner cavity of the cone bottom, and also uses an improved lock stitching method; the cone top circle is completely filled with a number of equilateral triangles with stitches set at the vertices of the triangles, and the cone top circle stitching is completed according to the stitching stitches.

4. The method for sewing a small-sized capped radome fabric according to claim 3, characterized in that: The four-step cone stitching in S4-1 is specifically as follows: the first step of cone stitching is to place the middle section stitching mold close to the outer surface of the preform fabric and use a number of positioning needles to pass through the positioning holes on the surface of the middle section stitching mold to penetrate the preform fabric and complete the positioning through the through hole at the center line of the sheet-shaped cone inner mold, then remove the sheet-shaped cone inner mold corresponding to the middle section stitching mold, and use the improved lock stitching method to stitch according to the through hole on the surface of the middle section stitching mold; before stitching, use a prefabricated hole needle to punch a prefabricated hole at the point to be stitched, and after withdrawing the prefabricated hole needle, insert the stitching thread into the threading hole at the needle tip of the machine needle, penetrate into the preform fabric, and stitch it in its Leave a thread loop in the inner cavity, then use a slender crochet hook to hook out the thread loop and insert it into the bottom line, then pull out the machine needle to lock the thread loop in the inner cavity of the preform fabric, complete the sewing at one point, and sew according to this step at the next sewing point to perform the first step of cone sewing; after completing the sewing, remove the middle section sewing mold, and then install the sheet-shaped conical inner mold at this position to complete the first step of cone sewing; in the second step, rotate the middle section sewing mold 90 degrees clockwise along the circumference of the fabric compared to the position of the middle section sewing mold in the first step, and insert the positioning needle again for positioning, and complete the second step of cone sewing according to the steps in the first step; the cone sewing of the third and fourth steps is completed in sequence according to this step.

5. The method for sewing a small-sized capped radome fabric according to claim 3, characterized in that: The N-shaped path suturing method in S4-2 is specifically as follows: the solid cone top is divided into several circumferential suturing positions every 3 mm in the upward direction of the Z axis. In the first step of circumferential suturing, the suturing needle penetrates the solid cone top and sews back from the other side in parallel at an equal distance of 3 mm, and sews in sequence along the horizontal direction to complete the first step of circumferential suturing; in the second step of circumferential suturing, the second step of circumferential suturing position is found along the direction of the cone top, that is, along the Z axis at an equal distance of 3 mm. The suturing point is deflected 45 degrees clockwise compared with the suturing point of the previous step. This deflection of the suturing angle effectively improves the structural strength of the fabric and reduces the risk of delamination. The suturing operation of the first step is repeated to complete the second step of circumferential suturing; the second step of circumferential suturing is repeated until the suturing part of the solid cone top is completed by suturing upward.

Images