Sewing device and sewing method for small-size top-sealed radome fabric

Abstract

The invention relates to a sewing device for small-size top-sealed radome fabric. The sewing device comprises a workbench, a mounting plate, an assembly core mold and a middle-section sewing mold, the combined core mold consists of four sheet-shaped conical inner molds and is connected with the mounting plate through a flange plate; through holes are uniformly distributed in the center line of each sheet-shaped conical inner mold; one end of the mounting plate is fixedly provided with the combined core mold, and the other end is fixedly provided with the workbench; the middle-section sewing die is of a sheet-shaped arc-shaped structure, a plurality of through holes are evenly distributed in the middle-section sewing die, and the adjacent through holes in the length direction of the middle-section sewing die are communicated to form wire grooves; a plurality of positioning holes matched with the positioning needles in size are further formed in the middle of the middle-section sewing mold in the length direction of the middle-section sewing mold; the outer surface of the assembly core mold is attached to the inner surface of a to-be-sewn preform fabric, and the inner surface of the middle section sewing mold is attached to the outer surface of the to-be-sewn preform fabric and is fixed through a positioning needle; the invention further provides a suturing method using the suturing device. The high-quality sewing machine can achieve high-quality sewing of the fabric with the narrow inner space.

Description

Technical Field

[0001] The 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 lines 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 a lot of research on the preparation method of antenna cover preform fabric. The patent name is a preparation method of a conical high-performance fiber antenna cover preform fabric (patent number CN201910602618.8), which provides a molding method for antenna cover preform fabric with a conical shape. Positioning holes are punched on the mold, and positioning needles are manually inserted to locate the suture points. After positioning, the surface mold needs to be removed, and then the S-shaped track is sewn. The whole process is relatively complicated, and the S-shaped track sewing method is difficult to meet the sewing molding of small-sized capping fabrics with narrow internal space. The patent name is sewing weaving and special sewing mold for fiber fabrics for antenna covers (patent number CN201510413474.3), which provides a sewing mold and sewing method for rotary cone-shaped antenna cover fabrics. Long sewing holes are opened on the surface of the mold for sewing. The position of the sewing track points is difficult to control, and the uniformity and quality of the sewing are difficult to guarantee. In summary, the existing sewing technology is difficult to meet the high-quality sewing molding of small-sized capping antenna cover fabrics with narrow internal space. 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 a 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 sewing device for a small-sized capped antenna cover fabric comprises a workbench, a mounting plate, a combined core mold and a middle-section sewing mold; the combined 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 combined 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; a plurality of positioning holes matching the size of the positioning pins are also provided in the middle of the middle-section sewing mold 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.

[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 matching the flange are evenly distributed around the core mold mounting hole, and a mounting hole connecting to the workbench mounting plate is provided at the other end.

[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 a plurality of φ2 through holes arranged longitudinally at an equal distance of 10 mm from the bottom to the top at its center position; 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 the workspace; S2, ply design and raw material preparation: dividing the preform fabric of the small-sized capped radome of the rotating body to be prepared into four equal parts in space, and flattening it into a plurality of unit layer plies and cone top difference layers according to its thickness and the thickness of the quartz cloth, and cutting the unfolded unit layer plies and cone top difference layers on the quartz cloth; S3, ply: laying the prepared unit layer plies and cone top difference layers on the sewing mold in sequence, and arranging a plurality of cone top difference layers between two adjacent unit layer plies; 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 laying a semi-conical unit layer on the top and S2-2 to prepare a preform fabric for laying a cone top difference layer; the preform fabric of the small-sized capping antenna cover of the rotating body to be prepared is cut on the cutting surface along the two cone normals of the front view, and it is divided in space and the divided fabric surface is unfolded to obtain a half-piece unit layer laying 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 laying is spliced ​​every two to obtain a semi-conical unit layer laying on the top. Since the preform fabric of the small-sized capping antenna cover of the rotating body is used on high-speed flying satellites, a large amount of heat is generated due to friction with the air during high-speed flight, and the temperature it withstands is high, so 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, wherein the top semi-conical unit plies are laid in a clockwise manner with an increment of 45 degrees, so that the joints between two adjacent top semi-conical unit plies are staggered, thereby ensuring the structural stability of the preform fabric and avoiding stratification; S3-2, the ply is fixed, after laying a layer of top semi-conical unit plies, the fabric is tightly wound spirally from the top of the cone downward with nylon thread, the nylon thread at the top and bottom of the cone is fixed with short nails, and when laying the next layer of unit plies, the short nail at the top of the cone is first pulled out, and while the fabric is pressed, the next unit ply is laid while rotating 45 degrees clockwise compared to the previous unit ply, and when it is laid 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, 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 with a middle stitching mold in cooperation with a stitching device, and the preform fabric of the small-size capped antenna cover 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 the improved lock stitching method is also used, 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 plurality of positioning needles to penetrate the preform fabric through the positioning holes on the surface of the middle section sewing mold 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 stitching mold is removed, and the improved lock-stitching method is used to stitch according to the through hole on the surface of the middle-section stitching mold; before stitching, a prefabricated hole is punched at the point to be stitched with a prefabricated hole needle. After the prefabricated hole needle is withdrawn, the stitching thread is inserted into the threading hole at the needle tip of the machine needle, penetrated into the prefabricated fabric, and a thread sleeve is left in its inner cavity. The thread sleeve is hooked out with a slender hook and inserted into the bottom line, and then the machine needle is pulled out to lock the thread sleeve in the inner cavity of the prefabricated fabric, completing the stitching at one point, and stitching at the next stitching point according to this step to perform the first step of cone stitching; after stitching is completed, the middle-section stitching mold is removed, and the sheet-like conical inner mold at this position is installed again to complete the first step of cone stitching; in the second step, the middle-section stitching mold is rotated 90 degrees clockwise along the circumference of the fabric compared to the position of the middle-section stitching mold in the first step, and the positioning needle is inserted again for positioning, and the second step of cone stitching is completed according to the steps in the first step; the cone stitching 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, so 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-section sewing mold) to the top of the cone (the top part of the cover fabric), that is, the solid position above that cannot be sewn by the middle-section 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, and in the first step of circumferential sewing, the sewing needle penetrates the solid cone top and equidistantly penetrates and sews back from the other side in parallel at 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, equidistantly 3mm upward along the Z axis, and 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. Repeat the sewing operation of the first step to complete the second step of circumferential sewing; repeat the second step of circumferential sewing until the solid cone top sewing part is sewn upward.

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

[0018] 1. The present invention aims at the structural characteristics of the small-sized capped radome fabric and proposes a molding method of partitioned stitching and coupling of multiple stitching methods, which meets the high-quality stitching molding 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 small internal space of the fabric and difficulty in stitching, 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 suturing method to radially and axially suturing the top solid area, 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 the wire grooves on the middle section suture mold, thereby improving the accuracy of the suture point spacing and the suture quality.

[0022] 5. The combined core mold used in the present invention is made by resin-based 3D printing technology, with low manufacturing cost. Its mold surface has the same curved surface as the fabric covering surface, and after 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, which effectively prevents relative slippage between the covering surfaces during stitching and ensures the stability of the internal structure of the preform fabric.

[0023] 6. The interface positions are cross-distributed during the ply laying process of the present invention. At the same time, the cone top difference layer is set by a uniform intercalation method in the top variable thickness area, thereby ensuring the overall structural strength of the preform fabric and improving the thermal corrosion resistance of the fabric.

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

[0025] 8. When the detachable combined core mold adopted in the present invention is used to sew the preform fabric of the small-sized capped antenna cover, the detachable structure increases the sew space, making the sew process easy to carry out, 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 corresponding to the sew positions are removed in turn to prevent the fabric from being 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 is a schematic diagram of the sewing area of ​​the preform fabric in the present invention;

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

[0034] Fig. 9 It is a flow chart of cone stitching of preform fabric;

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

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

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

[0038] Fig.13 is a schematic diagram of the plying of the preform fabric;

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

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

[0041] Fig.16 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-combination 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-opposite semi-conical unit layer ply; 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 comprises a workbench 8, a mounting plate, a combined 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 a 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, and through holes are evenly distributed on the center line of each sheet-shaped conical inner mold; the assembly core mold 4 is fixed at one end of the mounting plate, and the workbench 8 is fixed at the other end; the middle section stitching mold 2 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 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 matching the size of the positioning needle 1 along its length direction (in this example, as shown in FIG. 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 combined 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 the center radius of 41.5 of the core mold mounting hole for matching with the flange 5), and two φ8.55 mounting holes for connecting with 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 to match with the flange mounting plate 6. The mounting hole diameter of the flange 5 is 46, and 8 M5 threaded holes are evenly distributed at the center radius of 26.5 of the mounting hole for connecting with the assembly core mold 4, and 8 M6 threaded holes are evenly distributed at the center radius of 41.5 of the mounting hole for connecting with the flange mounting plate 6.

[0050] The sheet-shaped conical inner mold is made by 3D printing, such as Figure 3 As shown, they are respectively 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, and two cylindrical countersunk holes for M5 hexagonal countersunk studs are evenly distributed at the bottom installation 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 paving surface and shape it into a rotating body preform fabric 3 during the laying process.

[0053] S2. Layer design and raw material preparation: Fig.12 As shown, the preform fabric 3 of the rotating body small-sized capped radome to be prepared is equally divided into four parts in space, and flattened into a plurality of 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 rotating body small-sized capped radome 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 the top semi-conical unit layer plies 16. Since the rotating small-sized capped antenna cover preform fabric 3 is used on high-speed flying satellites, 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 provide 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: laying the prepared unit layer plies and cone top difference layers 17 on the sewing mold in sequence, and setting a plurality of cone top difference layers 17 between two adjacent unit layer plies; the said S3 also includes S3-1 laying the top semi-conical unit plies 16 in clockwise order by 45 degrees, so that the joints between the two adjacent top semi-conical unit plies 16 are staggered, so as to ensure the structural stability of the preform fabric 3 and avoid delamination; S3-2 fixing the plies, after laying a layer of top semi-conical unit plies 16, use nylon thread 15 to spirally wrap the fabric tightly from the cone top downward, such as Fig.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, first pull out the short nail 14 at the top of the cone, and while pressing the fabric, lay the next unit layer 45 degrees clockwise compared with the previous unit layer. When laying to the short nail 14 at the bottom of the cone of the previous unit layer, wrap the fabric with the nylon line 15, and nail the short nail 14 at the top of the cone, then pull out the short nail 14 at the bottom of the cone of the previous unit layer, and nail it together with the next unit layer at the bottom of the cone, and then lay it back and forth in sequence.

[0055] S4, sewing: Sewing the laid rotating fabric in sequence 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 sew to the center of the middle section sew mold 2, the left side sew path 2.4 is sewn. 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. Fig. 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 equally divided into 4 parts along 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 holes at the center line of the sheet-like conical inner mold, and then remove the sheet-like conical inner mold corresponding to the middle section stitching mold 2, and use the improved lock-stitching method to stitch according to the through holes 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, penetrated into the preform fabric 3, and a thread sleeve is left in its inner cavity, and the thread sleeve 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 sleeve 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 then the sheet-like 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 perform through-suture on the solid cone top suture area 3.2, such as Fig.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 section sewing mold) 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 section 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 every 3mm along the Z axis. Fig.10 As shown in the six circumferential suture positions 3.2.1-3.2.6, in the first step of circumferential suture 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 step of circumferential suture; in the second step of circumferential suture 3.2.2, the second step of circumferential suture position is found along the direction of the cone top, that is, along the Z axis at an equal distance of 3mm upwards. The suture point is deflected 45 degrees clockwise compared with the suture point of the previous step. 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 step of circumferential suture; the second step of circumferential suture is repeated until the solid cone top suture part of the remaining four steps is completed by suturing upwards.

[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 inner cavity of the cone bottom, such as Fig.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 a number of regular triangles, the stitches are set at the vertices of the triangles, and the cone top circle is sutured according to the stitches. Fig.11 Take the middle stitch 3.3.1 as an example to perform the cone-top circle improved lock suture. The specific steps are as follows: Fig.12 As shown in 3.3.1.1 to 3.3.1.6, since the small cover body preform has completed the S4-1 cone stitching and the S4-2 solid cone top stitching, the small cover body has a certain rigidity at this time, 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 stitching process, only the first core module 4.1 can be used for support when the cone top circle is stitched, and the prefabricated hole needle 9 and the suture needle 10 are stitched in the other three inner cavity areas where the core mold is not installed. In order to prevent the small cover body from rotating during the cone top circle stitching process, an outer covering middle section stitching mold 2 is used in conjunction with the positioning needle 1 to limit the freedom of rotation of the small cover body, so that the cone top circle stitching process can proceed smoothly, as shown in FIG. Fig.12 At this time, the 3.3.1 stitch cone top circle sewing only retains the first core module 4.1 to support the small cover body 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 body during the sewing process, such as Fig.12As shown in 3.3.1.1-3.3.1.6, the other three core modules except the first core module 4.1 are removed, and the corresponding area of ​​the first core module 4.1 is covered with the middle section sewing mold 2, and the positioning needle 1 is used to penetrate the small cover and the through hole at the center of the first core module 4.1 to complete the positioning. Fig.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 from the prefabricated hole, and a thread loop is left in the inner cavity. Then a slender crochet hook 13 is used to hook out the thread loop and insert the bottom thread 12. Then the suture needle 10 withdraws from the prefabricated hole and locks the thread loop to complete the suturing at one point. After that, 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, but 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 section stitching mold 2 and positioning needle 1 that interfere with the prefabricated hole needle 9 and the stitching needle 10 are removed, and the middle section stitching mold 2 and the positioning needle 1 are installed at 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 the stitching of all the stitching parts of the cone top circle stitching area 3.3 is completed. And so on 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, so 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 the preferred embodiments of the present invention are described above, the present invention is not limited to the above specific embodiments, which are merely illustrative and not restrictive. Under the guidance of the present invention, a person skilled in the art can make many forms without departing from the scope of the present invention and the claims. All of these belong to the protection scope of the present invention.

Claims

1. A sewing device for a small-sized capped radome fabric, characterized in that: It includes a workbench, a mounting plate, a combined core mold and a middle-section stitching mold; the combined 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 combined core mold, and the other end is fixed with the workbench; the middle-section stitching mold is a sheet-like arc structure and is evenly distributed with a plurality of through holes, and the adjacent through holes along the length direction of the middle-section stitching mold are connected to form a wire groove; the middle part of the middle-section stitching 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 stitched, and the inner surface of the middle-section stitching mold fits the outer surface of the preform fabric to be stitched and is fixed by the positioning pin.

2. The sewing device for a small-sized capped radome fabric according to claim 1, characterized in that: The mounting plate includes a flange mounting plate and a workbench mounting plate; a light hole is provided at one end of the flange mounting plate as a core mold mounting hole, and mounting holes matching the flange are evenly distributed around the core mold mounting hole, and a mounting hole connected to the workbench mounting plate is provided at the other end.

3. The sewing device for a small-sized capped radome fabric according to claim 1, characterized in that: 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.

4. The sewing device for a small-sized capped radome fabric according to claim 1, characterized in that: The sheet-like conical inner mold is made by 3D printing, has a thickness of 5 mm and is provided with a plurality of through holes arranged longitudinally at an equal distance of 10 mm from the bottom to the top at its center; and two cylindrical countersunk holes are evenly distributed at its bottom mounting position.

5. A method for sewing a small-sized capped radome fabric, using the sewing device according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Place the sewing device: place the installed sewing device in the workspace; S2. Laying design and raw material preparation: divide the preform fabric of the small-size capped antenna cover of the rotating body to be prepared into four equal parts in space, and flatten it into several unit layer layups and cone top difference layers according to its thickness and the thickness of the quartz cloth, and cut the unfolded unit layer layups and cone top difference layers on the quartz cloth; S3. Laying: lay the prepared unit layer layups and cone top difference layers on the sewing mold in turn, and set several cone top difference layers between two adjacent unit layer layups; S4. Sewing: sew the laid rotating body fabric in turn on the sewing mold.

6. The method for sewing a small-sized capped radome fabric according to claim 5, characterized in that: The S2 includes S2-1 to prepare a preform fabric ply with a semi-conical unit layer on top and S2-2 to prepare a preform fabric cone top difference layer; the preform fabric of the rotating body small-size capping antenna cover to be prepared is cut on the cutting surface along the two cone normals of the front view, it is divided in space and the divided fabric surface is unfolded to obtain a half-piece unit layer ply and a cone top difference layer, and the unfolded half-piece unit layer ply is spliced ​​every two to obtain a ply with a semi-conical unit layer on top.

7. The method for sewing a small-sized capped radome fabric according to claim 5, characterized in that: The S3 also includes S3-1, which is laid in a clockwise manner with an increment of 45 degrees, so that the joints between two adjacent semi-conical unit plies are staggered; S3-2, the ply is fixed, after laying a layer of semi-conical unit plies, the fabric is tightly wound spirally from the top of the cone downward with nylon thread, the nylon thread at the top and bottom of the cone is fixed with short nails, when laying the next layer of unit ply, the short nail at the top of the cone is pulled out first, and while the fabric is pressed, the next unit ply is laid with a clockwise rotation of 45 degrees compared with the previous unit ply, and when it is laid 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, 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 ply at the bottom of the cone, and it is laid back and forth in sequence.

8. The method for sewing a small-sized capped radome fabric according to claim 5, 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 cooperation with a stitching device, and the preform fabric of the small-size capped antenna cover 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 for four-step cone stitching; wherein the S4-2 solid cone top stitching is performed through stitching by 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 the improved lock stitching method is also used; 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.

9. The method for sewing a small-sized capped radome fabric according to claim 8, 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 Leave a thread loop in the inner cavity, hook it out with a slender crochet hook 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 at the next sewing point according to this step 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, 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.

10. The method for sewing a small-sized capped radome fabric according to claim 8, characterized in that: The N-shaped path suturing method in S4-2 is specifically as follows: the solid cone top is divided into a number of circumferential suturing positions equidistantly every 3 mm in the upward direction along the Z axis. In the first step of circumferential suturing, the suture needle penetrates the solid cone top and sews back from the other side in parallel at an equidistant interval 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 positions are found along the direction of the cone top, that is, along the Z axis at an equidistant interval of 3 mm. The suturing points are deflected 45 degrees clockwise compared to the suturing points in 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.

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