A stitching tool and stitching forming method for polar coordinate fabric stitched preform

Abstract

The application discloses a kind of polar coordinate fabric stitching preform stitching tool and stitching forming method.The stitching tool includes upper stitching clamping template, lower stitching clamping template, thickness control bolt and thickness control nut;According to stitching track, upper stitching clamping template and lower stitching clamping template are all opened with several identical long circular through holes;Thickness control bolt and thickness control nut are arranged on the circumference of upper stitching clamping template and lower stitching clamping template, for compacting layer fabric until target thickness.The application first proposes a kind of stitching tool and stitching forming method for the special stitching track requirement of polar coordinate fabric.Through the through hole of template inner dislocation, without replacing jig, polar coordinate fabric is simultaneously stitched in the clamping state of controllable thickness, solve the problem that the thickness of stitched fabric is difficult to control, and without disassembling tool in the process of stitching.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of preform composite material processing, and in particular to a stitching tool and a stitching forming method for polar coordinate fabric stitched preforms. BACKGROUND

[0002] The stitched fabric is a kind of three-dimensional fabric formed by connecting two-dimensional fabrics after laying through stitching lines. The stitched fabric composite has better delamination resistance and higher impact damage tolerance, and is the most common fabric structure of fiber preforms of composite materials at present. By designing the stitching trajectory, stitch density, and other stitching parameters, the mechanical, thermal, and thermomechanical properties of the formed composite material can be optimized and improved.

[0003] In the existing process technology, the fabric needs to be pre-shaped before stitching. The methods for shaping the thickness of the stitched fabric include coating a shaping agent, powder shaping, and transfer shaping. The shaping process generally introduces other substances into the stitched fabric preform, affecting the quality and performance of the composite material after composite forming. When the fabric is stitched according to the predetermined stitching trajectory, a needle tube is usually used for positioning, and a puncture machine is used to insert the needle tube, and then the fabric is stitched. The operation is complicated and not convenient for stitching forming. The traditional method cannot continuously stitch the fabric in a clamped state, and cannot accurately and uniformly control the thickness of the stitched fabric. It is also difficult to meet the stitching requirements when facing the polar coordinate circular area stitching trajectory. SUMMARY

[0004] To solve the technical problems of the prior art, the present application provides a stitching tool and a stitching forming method for polar coordinate fabric stitched preforms.

[0005] The technical solution of the stitching tool to solve the technical problem is to provide a stitching tool for polar coordinate fabric stitched preforms, characterized in that the stitching tool comprises an upper stitching clamping template, a lower stitching clamping template, a thickness control bolt, and a thickness control nut.

[0006] According to the stitching trajectory, a plurality of identical long circular holes are formed on the upper stitching clamping template and the lower stitching clamping template; the long edges of all the long circular holes have the same direction as the stitching direction of the stitching line; the long edge length of the long circular hole is equal to the stitch pitch X; and the diameters of the semicircles on both sides of the long circular hole are greater than the diameter of the stitching line for the stitching line to pass through.

[0007] According to the stitching direction, the shapes formed by connecting all the long circular holes on the upper stitching clamping template are the same as the shapes formed by connecting all the long circular holes on the lower stitching clamping template.

[0008] The stitching trajectory is composed of a plurality of stitching paths; in each stitching path, the spacing between two adjacent long circular through holes is equal to the stitching needle spacing X minus the diameter d of the semicircle; the long circular through holes on the upper stitching clamping template and the long circular through holes on the lower stitching clamping template in the same stitching path are spatially staggered, and the length of the stagger is equal to the stitching needle spacing X, the spatially coincident part forms a circular shape with a diameter of d and is used as a stitching hole for needle stitching;

[0009] The thickness control bolt and the thickness control nut are arranged in the circumferential direction of the upper stitching clamping template and the lower stitching clamping template, and the upper stitching clamping template and the lower stitching clamping template are connected into a whole through the thickness control bolt and the thickness control nut, for compacting the laid fabric until the target thickness.

[0010] The technical solution of the present application solves the technical problem of the method, which is to provide a stitching forming method of a polar coordinate fabric stitching preform, characterized in that the method comprises the following steps:

[0011] Step 1, determining the number of layers of the polar coordinate fabric according to the target thickness of the prepared polar coordinate fabric stitching preform and the thickness of the polar coordinate fabric;

[0012] According to the process requirements, the stitching trajectory is planned, and the stitching needle spacing X and the stitching line type and diameter are determined; the stitching trajectory is composed of a plurality of stitching paths;

[0013] Step 2, designing the stitching tool according to different working conditions respectively;

[0014] Step 3, laying the polar coordinate fabric on the lower stitching clamping template as the raw material, and obtaining the laid fabric after reaching the number of layers set in the step; then placing the upper stitching clamping template on the laid fabric, and clamping the laid fabric between the upper stitching clamping template and the lower stitching clamping template; then connecting the upper stitching clamping template and the lower stitching clamping template into a whole through the thickness control bolt and the thickness control nut, and compacting the laid fabric through the thickness control bolt and the thickness control nut, until the target thickness of the polar coordinate fabric stitching preform set in the step is reached, forming the fabric to be stitched;

[0015] Step 4, stitching the first stitching path with the stitching line according to the stitching trajectory; after completing the needle stitching of the stitching path, fixing the stitching line and replacing another stitching line for the next stitching path; repeating the above needle stitching process to stitch all the stitching paths along the stitching trajectory until the needle stitching of the stitching trajectory is completed;

[0016] Step 5, removing the thickness control bolt, the thickness control nut, the upper stitching clamping template and the lower stitching clamping template to obtain the polar coordinate fabric stitching preform.

[0017] Compared with the prior art, the present application has the beneficial effects that:

[0018] (1) The present application firstly proposes a sewing tool and a sewing forming method for the special sewing track requirements of polar coordinate fabric. Through the misaligned through holes in the template, the polar coordinate fabric is simultaneously sewn in the clamped state with controllable thickness without replacing the clamp, solving the problem of difficult control of the thickness of the sewn fabric, and without disassembling the tool during the sewing process, effectively improving the sewing efficiency of the polar coordinate fabric sewing preform.

[0019] (2) The present application uses the upper sewing clamping template and the lower sewing clamping template to clamp, sew, and position the layer fabric, and realizes the controllable clamping thickness of the polar coordinate fabric sewing preform by controlling the thickness control bolt and the thickness control nut to compact the layer fabric.

[0020] (3) The present application can effectively sew the complex sewing track of the polar coordinate fabric through the misaligned through holes in the template.

[0021] (4) The present application has the functions of thickness control, fabric shaping, and sewing positioning, effectively improving the fiber volume content of the polar coordinate fabric sewing preform, and stabilizing the quality of the finished product. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic diagram of the sewing tool of the present application;

[0023] Figure 2 is a schematic diagram of the upper sewing clamping template of embodiment 1 of the present application;

[0024] Figure 3 is a schematic diagram of the lower sewing clamping template of embodiment 1 of the present application;

[0025] Figure 4 is a schematic diagram of the principle of needle sewing of the present application;

[0026] Figure 5 is an exploded view of the sewing tool of embodiment 2 of the present application;

[0027] Figure 6 is an exploded view of the sewing tool of embodiment 3 of the present application.

[0028] In the figure, the upper sewing clamping template 1, the lower sewing clamping template 2, the long circular (i.e. runway-shaped) through hole 3, the thickness control bolt 4, the thickness control nut 5, the sewing line 6, the fabric to be sewn 7, the sliding groove 8, and the sliding block 9;

[0029] The upper clamping template 101, the upper sewing template 102, the lower clamping template 201, and the lower sewing template 202. DETAILED DESCRIPTION

[0030] The following gives specific embodiments of the present application. The specific embodiments are only for further detailed description of the present application, and do not limit the protection scope of the claims of the present application.

[0031] The present application provides a stitching tool for stitching a polar coordinate fabric preform (referred to as a stitching tool), characterized in that the stitching tool comprises an upper stitching clamping template 1, a lower stitching clamping template 2, a thickness control bolt 4 and a thickness control nut 5.

[0032] According to the stitching trajectory, a plurality of identical long circular through holes 3 are formed on the upper stitching clamping template 1 and the lower stitching clamping template 2; the long edges of all the long circular through holes 3 are in the same direction as the stitching direction of the stitching line; the long edge length of the long circular through hole 3 is equal to the stitching pitch X; the diameter d of the semicircle on both sides of the long circular through hole 3 is greater than the diameter of the stitching line 6, for the stitching line 6 to pass through;

[0033] According to the stitching direction, the shapes formed by connecting all the long circular through holes 3 on the upper stitching clamping template 1 are the same as the shapes formed by connecting all the long circular through holes 3 on the lower stitching clamping template 2.

[0034] The stitching trajectory is composed of a plurality of stitching paths; in each stitching path, the spacing between the adjacent two long circular through holes 3 is equal to the stitching pitch X minus the diameter d of the semicircle (i.e. X-d); the long circular through holes 3 on the upper stitching clamping template 1 and the long circular through holes 3 on the lower stitching clamping template 2 are spatially staggered in the same stitching path, and the length of the stagger is equal to the stitching pitch X, and the spatially coincident part forms a circular shape with a diameter of d and serves as a stitching hole for needle stitching.

[0035] The thickness control bolt 4 and the thickness control nut 5 are arranged in the circumferential direction of the upper stitching clamping template 1 and the lower stitching clamping template 2, and the upper stitching clamping template 1 and the lower stitching clamping template 2 are connected into a whole through the thickness control bolt 4 and the thickness control nut 5, for pressing the layer fabric until the target thickness.

[0036] Preferably, according to the stitching direction, the shapes formed by connecting all the long circular through holes 3 on the upper stitching clamping template 1 are a plurality of radial lines with the same center or a plurality of concentric circular rings. The center is the center of the upper stitching clamping template 1.

[0037] Preferably, the thickness control bolt 4 and the thickness control nut 5 are uniformly arranged in the circumferential direction of the upper stitching clamping template 1 and the lower stitching clamping template 2.

[0038] Preferably, the upper stitching clamping template 1 is composed of an upper clamping template 101 and an upper stitching template 102; the lower stitching clamping template 2 is composed of a lower clamping template 201 and a lower stitching template 202.

[0039] The upper stitching template 102 is detachably (preferably threadedly) mounted on the upper clamping template 101; the lower stitching template 202 is detachably (preferably threadedly) mounted on the lower clamping template 201; according to the stitching trajectory, a plurality of identical long circular through holes 3 are formed on the upper stitching template 102 and the lower stitching template 202; the thickness control bolts 4 and the thickness control nuts 5 are uniformly arranged on the circumferences of the upper clamping template 101 and the lower clamping template 201, and the upper clamping template 101 and the lower clamping template 201 are connected into a whole through the thickness control bolts 4 and the thickness control nuts 5, thereby forming a variable-stitching-trajectory stitching tool with replaceable stitching templates (i.e., replaceable long circular through holes 3).

[0040] Preferably, the upper stitching clamping template 1 is composed of the upper clamping template 101 and the upper stitching template 102; the lower stitching clamping template 2 is composed of the lower clamping template 201 and the lower stitching template 202.

[0041] The upper stitching template 102 is detachably (preferably threadedly) mounted on the upper clamping template 101; the lower stitching template 202 is detachably (preferably threadedly) mounted on the lower clamping template 201; according to the stitching trajectory, a plurality of identical long circular through holes 3 are formed on the upper stitching template 102 and the lower stitching template 202; the thickness control bolts 4 and the thickness control nuts 5 are uniformly arranged on the circumferences of the upper clamping template 101 and the lower clamping template 201, and the upper clamping template 101 and the lower clamping template 201 are connected into a whole through the thickness control bolts 4 and the thickness control nuts 5, thereby forming a variable-stitching-trajectory stitching tool with replaceable stitching templates (i.e., replaceable long circular through holes 3).

[0042] The application also provides a stitching forming method for polar coordinate fabric stitching preforms (referred to as the method), which is characterized by comprising the following steps:

[0043] Step 1: determining the number of plies of the polar coordinate fabric according to the target thickness of the prepared polar coordinate fabric stitching preform and the thickness of the polar coordinate fabric;

[0044] According to the process requirements, the stitching trajectory is planned, and the stitching needle spacing X, the selected stitching line type and the stitching line diameter are determined; the stitching trajectory is composed of a plurality of stitching paths;

[0045] Preferably, in step 1, the polar coordinate fabric is formed by polar coordinate weaving method, and the selected fiber is high-performance fiber such as carbon fiber, silicon carbide fiber, silicon nitride, aramid fiber, glass fiber, quartz fiber and alumina fiber.

[0046] Preferably, in step 1, Nt wherein r is the density, n is the number of ply, and d is the single strand linear density.

[0047] Step 2, design the stitching tooling:

[0048] Working condition one, the stitching tooling includes an upper stitching clamping template 1, a lower stitching clamping template 2, a thickness control bolt 4 and a thickness control nut 5;

[0049] According to the stitching trajectory, a plurality of identical long circular through holes 3 are machined on the upper stitching clamping template 1 and the lower stitching clamping template 2; the long edges of all long circular through holes 3 are in the same direction as the stitching direction of the stitching line; the long edge length of the long circular through hole 3 is equal to the stitching pitch X; the diameters of the semicircles on both sides of the long circular through hole 3 are greater than the diameter of the stitching line 6, and the size is accurate for the stitching line 6 to pass through;

[0050] According to the stitching direction, all long circular through holes 3 on the upper stitching clamping template 1 are connected to form the same shape as all long circular through holes 3 on the lower stitching clamping template 2;

[0051] In each stitching path, the spacing between the two adjacent long circular through holes 3 is equal to the stitching pitch X minus the diameter of the semicircle (i.e. X-d); the long circular through holes 3 on the upper stitching clamping template 1 and the long circular through holes 3 on the lower stitching clamping template 2 are spatially staggered in the same stitching path, and the length of the stagger is equal to the stitching pitch X, and the spatially coincident part forms a circular shape with a diameter of d and is used as a stitching hole for needle stitching;

[0052] Working condition two, on the basis of working condition one, the upper stitching clamping template 1 is composed of an upper clamping template 101 and an upper stitching template 102; the lower stitching clamping template 2 is composed of a lower clamping template 201 and a lower stitching template 202;

[0053] The upper stitching template 102 is detachably (preferably threadedly connected) installed on the upper clamping template 101; the lower stitching template 202 is detachably (preferably threadedly connected) installed on the lower clamping template 201; a plurality of identical long circular through holes 3 are formed on the upper stitching template 102 and the lower stitching template 202; the thickness control bolt 4 and the thickness control nut 5 are uniformly arranged on the circumferences of the upper clamping template 101 and the lower clamping template 201, and the upper clamping template 101 and the lower clamping template 201 are connected into a whole through the thickness control bolt 4 and the thickness control nut 5, forming a variable stitching trajectory stitching tooling with replaceable stitching templates (i.e. replaceable long circular through holes 3);

[0054] Working condition three, on the basis of working condition one, the upper stitching clamping template 1 is composed of an upper clamping template 101 and an upper stitching template 102; the lower stitching clamping template 2 is composed of a lower clamping template 201 and a lower stitching template 202;

[0055] The upper stitching template 102 is detachably (preferably threadedly) mounted on the upper clamping template 101; the lower stitching template 202 is detachably (preferably threadedly) mounted on the lower clamping template 201; a plurality of concentric radial sliding grooves 8 are formed on the upper stitching template 102 and the lower stitching template 202; a sliding block 9 is slidably mounted in each sliding groove 8; a plurality of identical long circular through holes 3 are formed on each sliding block 9; thickness control bolts 4 and thickness control nuts 5 are uniformly arranged on the circumferences of the upper clamping template 101 and the lower clamping template 201, and the upper clamping template 101 and the lower clamping template 201 are connected into a whole through the thickness control bolts 4 and the thickness control nuts 5, forming a variable stitching trajectory stitching tool with replaceable stitching templates (i.e. replaceable long circular through holes 3);

[0056] Step 3, layering, positioning, and compacting: layering is performed on the lower stitching clamping template 2 using polar coordinate fabric as raw material, and after reaching the set number of layers in step 1, a layered fabric is obtained; then the upper stitching clamping template 1 is placed on the layered fabric, and the layered fabric is clamped between the upper stitching clamping template 1 and the lower stitching clamping template 2; then the upper stitching clamping template 1 and the lower stitching clamping template 2 are connected into a whole through the thickness control bolts 4 and the thickness control nuts 5, and the layered fabric is compacted by controlling the thickness control bolts 4 and the thickness control nuts 5 until the target thickness of the polar coordinate fabric stitched preform set in step 1 is reached, forming a fabric to be stitched 7;

[0057] Step 4, needle threading and stitching: according to the stitching trajectory, a sewing needle is used to pull a sewing thread 6 to perform needle threading and stitching on the first stitching path; after completing the needle threading and stitching of this stitching path, the sewing thread 6 is fixed and another sewing thread 6 is replaced for stitching of the next stitching path; the above needle threading and stitching process is repeated to sequentially perform needle threading and stitching on all stitching paths along the stitching trajectory until the needle threading and stitching of the stitching trajectory is completed;

[0058] Preferably, in step 4, the specific process of needle threading and stitching of each stitching path is as follows: the upper stitching clamping template 1 tightly abuts against the A face of the fabric to be stitched 7, and the lower stitching clamping template 2 tightly abuts against the B face of the fabric to be stitched 7; first, in the first long circular through hole 3 of the lower stitching clamping template 2, one end of the sewing thread 6 is fixed at the starting half circle of the long circular through hole 3, and then the sewing thread 6 is stitched along the B face for a length of X (X is the stitching pitch of step 1); then the sewing thread 6 is pierced from the B face to the A face of the fabric to be stitched 7, at which time the sewing thread 6 is located in the first long circular through hole 3 of the upper stitching clamping template 1; after stitching along the A face for a length of X, the sewing thread 6 is pierced from the A face to the B face of the fabric to be stitched 7, at which time the sewing thread 6 is located in the second long circular through hole 3 of the lower stitching clamping template 2; the above stitching rule is followed until the stitching at the last long circular through hole 3 is completed, and then the needle threading and stitching of this stitching path is completed.

[0059] Preferably, in step 4, in the working condition two, if it is necessary to change the stitching trajectory during the needle threading and stitching process, the upper stitching template 102 is detached from the upper clamping template 101, and the lower stitching template 202 is detached from the lower clamping template 201; then the upper stitching template 102 and the lower stitching template 202 with the same other stitching trajectory are replaced and detachably installed on the upper clamping template 101 and the lower clamping template 201 respectively, and the subsequent needle threading and stitching process is continued.

[0060] Preferably, in step 4, in the working condition three, if it is necessary to change the stitching trajectory during the above-mentioned needle threading and stitching process, the upper stitching template 102 is detached from the upper clamping template 101, and the lower stitching template 202 is detached from the lower clamping template 201; then the slider 9 with the same other number of long circular through holes 3 is replaced and slidably installed in the corresponding sliding groove 8 of the upper stitching template 102 and the lower stitching template 202 respectively, and the upper stitching template 102 and the lower stitching template 202 are detachably installed on the upper clamping template 101 and the lower clamping template 201 respectively, and the subsequent needle threading and stitching process is continued.

[0061] Step 5, remove the thickness control bolt 4, the thickness control nut 5, the upper stitching clamping template 1 and the lower stitching clamping template 2 to obtain the polar coordinate fabric stitching preform.

[0062] Example 1

[0063] In this embodiment, the stitching tool is as follows: according to the stitching direction, all the long circular through holes 3 on the upper stitching clamping template 1 are connected to form 18 concentric radial lines.

[0064] The method comprises the following steps:

[0065] Step 1, prepare a 10mm-thick polar coordinate fabric stitching preform, select a carbon fiber polar coordinate fabric with a thickness of 0.5mm, and the number of plies is 20;

[0066] The stitching needle spacing X is 10mm, the stitching thread 6 is selected to be 12K two-ply carbon fiber yarn, and the diameter of the stitching thread 6 is 0.8529mm; the stitching trajectory is composed of 18 stitching paths;

[0067] Step 2, according to the stitching trajectory, 90 long circular through holes 3 are machined on the upper stitching clamping template 1 and the lower stitching clamping template 2 respectively; the long edges of all the long circular through holes 3 have the same direction as the stitching direction of the stitching thread; the length of the long edges of the long circular through holes 3 is equal to 10mm; the diameters d of the semicircles on both sides of the long circular through holes 3 are 0.9mm;

[0068] Connecting in the suture direction, the shape formed by connecting all the long circular through holes 3 on the upper suture clamping template 1 is the same as the shape formed by connecting all the long circular through holes 3 on the lower suture clamping template 2, both of which are 18 concentric radial lines;

[0069] In each suture path, the distance between two adjacent long circular through holes 3 is equal to 9.1 mm; the long circular through holes 3 on the upper suture clamping template 1 and the long circular through holes 3 on the lower suture clamping template 2 are staggered in space in the same suture path, and the length of the stagger is equal to the suture needle distance X, and the part of the space overlap forms a circle with a diameter d and is used as a suture hole for needle suture;

[0070] Step 3, lay up 20 layers on the lower suture clamping template 2 using carbon fiber polar coordinate fabric as raw material to obtain a laid-up fabric; then place the upper suture clamping template 1 on the laid-up fabric, and then clamp the laid-up fabric between the upper suture clamping template 1 and the lower suture clamping template 2; then connect the upper suture clamping template 1 and the lower suture clamping template 2 into a whole through the thickness control bolt 4 and the thickness control nut 5, and compact the laid-up fabric by controlling the thickness control bolt 4 and the thickness control nut 5 until the thickness reaches 10 mm to form a to-be-sutured fabric 7;

[0071] Step 4, according to the suture trajectory, use the suture line 6 to perform needle suture on the first radial suture path; after completing the needle suture of the suture path, fix the suture line 6 and replace another suture line 6 for suture of the next suture path; repeat the above needle suture process to perform needle suture on all suture paths along the suture trajectory until the needle suture of the suture trajectory is completed;

[0072] Step 5, remove the thickness control bolt 4, the thickness control nut 5, the upper suture clamping template 1 and the lower suture clamping template 2 to obtain a polar coordinate fabric suture preform.

[0073] Example 2

[0074] When the preform is more complicated to change or add other suture trajectories, the suture tool used in this embodiment is that: the upper suture clamping template 1 and the lower suture clamping template 2 are changed into a split structure: the upper suture clamping template 1 is composed of an upper clamping template 101 and an upper suture template 102; the lower suture clamping template 2 is composed of a lower clamping template 201 and a lower suture template 202; the upper suture template 102 is detachably mounted on the upper clamping template 101; the lower suture template 202 is detachably mounted on the lower clamping template 201; according to the suture trajectory, a plurality of identical long circular holes 3 are formed on the upper suture template 102 and the lower suture template 202; the thickness control bolts 4 and the thickness control nuts 5 are uniformly arranged on the circumferences of the upper clamping template 101 and the lower clamping template 201, and the upper clamping template 101 and the lower clamping template 201 are connected into a whole through the thickness control bolts 4 and the thickness control nuts 5 to form a suture tool with variable suture trajectories and replaceable suture templates.

[0075] According to the suture direction, all the long circular holes 3 on the upper suture clamping template 1 are connected to form a shape of 4 concentric circular rings.

[0076] The method comprises the following steps:

[0077] Step 1, prepare a 10mm-thick polar coordinate fabric suture preform, select a 0.5mm-thick silicon carbide fiber polar coordinate fabric, and the number of layers is 20;

[0078] The suture needle spacing X is 10mm, the suture thread 6 is selected to be a 6K four-ply silicon carbide fiber, and the diameter of the suture thread 6 is 0.6263mm; the suture trajectory is composed of 18 suture paths;

[0079] Step 2, according to the suture trajectory, 56 identical long circular holes 3 are machined on the upper suture template 102 and the lower suture template 202 respectively; the trend of the long edges of all the long circular holes 3 is the same as the suture direction of the suture thread; the length of the long edges of the long circular holes 3 is equal to 10mm; the diameters d of the semicircles on both sides of the long circular holes 3 are 0.7mm;

[0080] According to the suture direction, all the long circular holes 3 on the upper suture template 102 are connected to form a shape which is the same as that of all the long circular holes 3 on the lower suture template 202, and both are 4 concentric circular rings;

[0081] In each suture path, the spacing between the two adjacent long circular holes 3 is equal to 9.3mm; in the same suture path, the long circular holes 3 on the upper suture template 102 and the long circular holes 3 on the lower suture template 202 are spatially staggered, and the length of the stagger is equal to the suture needle spacing X; the spatially coincident part forms a circular shape with a diameter d and is used as a suture hole for needle suture;

[0082] Step 3, layering on the lower stitching clamping template 2 with the carbon fiber polar coordinate fabric as raw material, laying 20 layers to obtain a layered fabric; then placing the upper stitching clamping template 1 on the layered fabric, and further clamping the layered fabric between the upper stitching clamping template 1 and the lower stitching clamping template 2; then connecting the upper stitching clamping template 1 and the lower stitching clamping template 2 into a whole through the thickness control bolt 4 and the thickness control nut 5, and compacting the layered fabric by controlling the thickness control bolt 4 and the thickness control nut 5 until the thickness reaches 10 mm, to form a to-be-stitched fabric 7;

[0083] Step 4, according to the stitching trajectory, using the stitching thread 6 to stitch the first radial stitching path; after completing the needle threading and stitching of the stitching path, fixing the stitching thread 6 and replacing another stitching thread 6 to stitch the next stitching path; repeating the above needle threading and stitching process to needle thread and stitch all stitching paths along the stitching trajectory until the needle threading and stitching of the stitching trajectory is completed.

[0084] In the above needle threading and stitching process, if it is necessary to change the stitching trajectory, the upper stitching template 102 is detached from the upper clamping template 101, and the lower stitching template 202 is detached from the lower clamping template 201; then replacing the upper stitching template 102 and the lower stitching template 202 with the same other stitching trajectory are detachably installed on the upper clamping template 101 and the lower clamping template 201, respectively, and then continuing the subsequent needle threading and stitching process.

[0085] Step 5, removing the thickness control bolt 4, the thickness control nut 5, the upper stitching clamping template 1 and the lower stitching clamping template 2 to obtain a polar coordinate fabric stitched preform.

[0086] Example 3

[0087] When the preform is more complicated to change or increase the suture line of other suture trajectories, the suture tool used in the embodiment is that: the upper suture clamping template 1 and the lower suture clamping template 2 are changed into a split structure: the upper suture clamping template 1 is composed of an upper clamping template 101 and an upper suture template 102; the lower suture clamping template 2 is composed of a lower clamping template 201 and a lower suture template 202; the upper suture template 102 is detachably mounted on the upper clamping template 101; the lower suture template 202 is detachably mounted on the lower clamping template 201; according to the suture trajectory, 12 concentric radial sliding grooves 8 are opened on the upper suture template 102 and the lower suture template 202; a sliding block 9 is slidingly installed in each sliding groove 8; five identical long circular through holes 3 are opened on each sliding block 9; the thickness control bolt 4 and the thickness control nut 5 are arranged on the circumference of the upper clamping template 101 and the lower clamping template 201, and the upper clamping template 101 and the lower clamping template 201 are connected into a whole through the thickness control bolt 4 and the thickness control nut 5, forming a suture tool with variable suture trajectory and replaceable suture template.

[0088] The method comprises the following steps:

[0089] Step 1, prepare a 10mm-thick polar coordinate fabric suture preform, select a 0.4mm-thick silicon carbide fiber polar coordinate fabric, and lay 20 layers;

[0090] The suture needle spacing X is 10mm, the suture thread 6 is selected to be a 12K two-ply carbon fiber, and the diameter of the suture thread 6 is 0.8529mm; the suture trajectory is composed of 18 suture paths;

[0091] Step 2, according to the suture trajectory, 12 concentric radial sliding grooves 8 are machined on the upper suture template 102 and the lower suture template 202, respectively, and a sliding block 9 is slidingly installed in each sliding groove 8; five identical long circular through holes 3 are machined on each sliding block 9; the long edges of all long circular through holes 3 are in the same direction as the suture direction; the long edge length of the long circular through hole 3 is equal to 10mm; the diameters d of the semicircles on both sides of the long circular through hole 3 are 0.9mm;

[0092] Connect according to the suture direction, all long circular through holes 3 on the upper suture template 102 are connected to form the same shape as all long circular through holes 3 on the lower suture template 202, which are connected to form 12 concentric radial lines;

[0093] In each suture path, the spacing between two adjacent long circular through holes 3 is equal to 9.1mm; in the same suture path, the long circular through holes 3 on the upper suture template 102 and the long circular through holes 3 on the lower suture template 202 are spatially staggered, and the length of the stagger is equal to the suture needle spacing X; the spatially coincident part forms a circular shape with a diameter d and is used as a suture hole for needle suture;

[0094] Step 3, carbon fiber polar coordinate fabric is used as raw material to lay up on the lower stitching clamping template 2, 20 layers are laid up to obtain a laid-up fabric; then the upper stitching clamping template 1 is placed on the laid-up fabric, and the laid-up fabric is clamped between the upper stitching clamping template 1 and the lower stitching clamping template 2; then the upper stitching clamping template 1 and the lower stitching clamping template 2 are connected into a whole through the thickness control bolt 4 and the thickness control nut 5, the laid-up fabric is compacted by controlling the thickness control bolt 4 and the thickness control nut 5, until the thickness reaches 10 mm, and the to-be-stitched fabric 7 is formed;

[0095] Step 4, according to the stitching trajectory, the first radial stitching path is stitched by using the stitching line 6; after the stitching of the stitching path is completed, the stitching line 6 is fixed and another stitching line 6 is replaced to stitch the next stitching path; the above stitching process is repeated, and the stitching of all stitching paths along the stitching trajectory is completed until the stitching of the stitching trajectory is completed.

[0096] In the above stitching process, if the stitching trajectory needs to be changed, the upper stitching template 102 is detached from the upper clamping template 101, and the lower stitching template 202 is detached from the lower clamping template 201; then the slider 9 with the same number of other long circular through holes 3 is replaced and is slidably installed in the corresponding sliding groove 8 of the upper stitching template 102 and the lower stitching template 202, respectively; then the upper stitching template 102 and the lower stitching template 202 are detachably installed on the upper clamping template 101 and the lower clamping template 201, respectively, and the subsequent stitching process is continued.

[0097] Step 5, the thickness control bolt 4, the thickness control nut 5, the upper stitching clamping template 1 and the lower stitching clamping template 2 are removed to obtain a polar coordinate fabric stitched preform.

[0098] The unmentioned parts of the present application are applicable to the prior art.

Claims

1. A stitching tool for stitching a polar fabric stitched preform, characterized in that, The stitching tool comprises an upper stitching clamping template (1), a lower stitching clamping template (2), a thickness control bolt (4) and a thickness control nut (5); According to the stitching trajectory, a plurality of identical long circular through holes (3) are formed on the upper stitching clamping template (1) and the lower stitching clamping template (2); the long edges of all the long circular through holes (3) are in the same direction as the stitching direction of the stitching line; the long edge length of the long circular through hole (3) is equal to the stitching pitch X; the diameters of the semicircles on both sides of the long circular through hole (3) are greater than the diameter of the stitching line (6) and are used for the stitching line (6) to pass through; According to the stitching direction, the shapes formed by the mutual connection of all the long circular through holes (3) on the upper stitching clamping template (1) are the same as the shapes formed by the mutual connection of all the long circular through holes (3) on the lower stitching clamping template (2), and are a plurality of radial lines or a plurality of concentric circles; the center is the center of the upper stitching clamping template (1); The stitching trajectory is composed of a plurality of stitching paths; in each stitching path, the distance between the adjacent two long circular through holes (3) is equal to the stitching pitch X minus the diameter d of the semicircle; the long circular through holes (3) on the upper stitching clamping template (1) and the long circular through holes (3) on the lower stitching clamping template (2) are staggered in space in the same stitching path, and the length of the stagger is equal to the stitching pitch X, the space overlapping part forms a circular shape with a diameter of d and is used as a stitching hole for needle stitching; the specific process of needle stitching of each stitching path is as follows: the upper stitching clamping template (1) is tightly attached to the A surface of the fabric to be stitched (7), and the lower stitching clamping template (2) is tightly attached to the B surface of the fabric to be stitched (7); first, in the first long circular through hole (3) of the lower stitching clamping template (2), one end of the stitching line (6) is fixed at the starting semicircle of the long circular through hole (3), and then the stitching line (6) is stitched along the B surface by X length; then it is pierced from the B surface to the A surface of the fabric to be stitched (7) through the stitching hole, at this time the stitching line (6) is located in the first long circular through hole (3) of the upper stitching clamping template (1); after stitching X length along the A surface, it is pierced from the A surface to the B surface of the fabric to be stitched (7) through the stitching hole, at this time the stitching line (6) is located in the second long circular through hole (3) of the lower stitching clamping template (2); follow this stitching rule until the stitching at the last long circular through hole (3) is completed, and then the needle stitching of the stitching path is completed; The thickness control bolt (4) and the thickness control nut (5) are arranged on the circumference of the upper stitching clamping template (1) and the lower stitching clamping template (2), and the upper stitching clamping template (1) and the lower stitching clamping template (2) are connected into a whole through the thickness control bolt (4) and the thickness control nut (5), which are used for pressing the laid fabric until the target thickness is reached; The upper stitching clamping template (1) is composed of an upper clamping template (101) and an upper stitching template (102); the lower stitching clamping template (2) is composed of a lower clamping template (201) and a lower stitching template (202); The upper stitching template (102) is detachably mounted on the upper clamping template (101); the lower stitching template (202) is detachably mounted on the lower clamping template (201); the thickness control bolt (4) and the thickness control nut (5) are arranged on the circumference of the upper clamping template (101) and the lower clamping template (201), and the upper clamping template (101) and the lower clamping template (201) are connected into a whole through the thickness control bolt (4) and the thickness control nut (5), forming a stitching tool with variable stitching trajectory of replaceable stitching template.

2. The polar fabric stitched preform stitching tool of claim 1, wherein, The thickness control bolt (4) and the thickness control nut (5) are uniformly arranged on the circumference of the upper stitching clamping template (1) and the lower stitching clamping template (2).

3. The polar fabric stitched preform stitching tooling of claim 1, wherein, According to the stitching trajectory, a plurality of identical long circular through holes (3) are formed on the upper stitching template (102) and the lower stitching template (202).

4. The polar fabric stitched preform stitching tool of claim 1, wherein, According to the stitching trajectory, a plurality of concentric radial sliding grooves (8) are formed on the upper stitching template (102) and the lower stitching template (202); a sliding block (9) is slidably mounted in each sliding groove (8); a plurality of identical long circular through holes (3) are formed on each sliding block (9).

5. A stitch-forming method for stitch-forming a polar fabric stitched preform, characterized in that, The method comprises the following steps: Step 1, according to the target thickness of the polar coordinate fabric stitching preform and the thickness of the polar coordinate fabric, determine the number of layers of the polar coordinate fabric; According to the process requirements, plan the stitching trajectory, and determine the stitching needle spacing X and the stitching line type and diameter; the stitching trajectory is composed of a plurality of stitching paths; Step 2, design the stitching tool: Case 1, use the stitching tool of any one of claims 1-2; Case 2, use the stitching tool of claim 3; Case 3, use the stitching tool of claim 4; Step 3, lay the polar coordinate fabric on the lower stitching clamping template (2) as the raw material, reach the number of layers set in step 1 to obtain the layered fabric; then place the upper stitching clamping template (1) on the layered fabric, and then clamp the layered fabric between the upper stitching clamping template (1) and the lower stitching clamping template (2); then connect the upper stitching clamping template (1) and the lower stitching clamping template (2) into a whole through the thickness control bolt (4) and the thickness control nut (5), and compact the layered fabric by controlling the thickness control bolt (4) and the thickness control nut (5), until the target thickness of the polar coordinate fabric stitching preform set in step 1 is reached, forming the to-be-stitched fabric (7); Step 4, according to the stitching trajectory, use the stitching line (6) to stitch the first stitching path; after completing the needle stitching of the stitching path, fix the stitching line (6) and replace another stitching line (6) to stitch the next stitching path; repeat the above needle stitching process to stitch all the stitching paths along the stitching trajectory until the needle stitching of the stitching trajectory is completed; Step 5, remove the thickness control bolt (4), the thickness control nut (5), the upper stitching clamping template (1) and the lower stitching clamping template (2) to obtain the polar coordinate fabric stitching preform.

6. The stitch-forming process for polar coordinate fabric stitched preforms according to claim 5, wherein, In step 1, the polar coordinate fabric is formed by a polar coordinate weaving method, and the fiber is selected from carbon fiber, silicon carbide fiber, silicon nitride, aramid fiber, glass fiber, quartz fiber or alumina fiber.

7. The stitch-forming method of claim 5, wherein, In step 4, the specific process of needle stitching of each stitching path is as follows: the upper stitching clamping template (1) is tightly attached to the A surface of the fabric to be stitched (7), and the lower stitching clamping template (2) is tightly attached to the B surface of the fabric to be stitched (7); first, one end of the stitching line (6) is fixed at the starting half circle of the first long circular hole (3) of the lower stitching clamping template (2), and then stitched along the B surface for X length; then, the stitching line (6) is pierced from the B surface to the A surface of the fabric to be stitched (7), at this time the stitching line (6) is located in the first long circular hole (3) of the upper stitching clamping template (1); after stitching along the A surface for X length, the stitching line (6) is pierced from the A surface to the B surface of the fabric to be stitched (7), at this time the stitching line (6) is located in the second long circular hole (3) of the lower stitching clamping template (2); follow this stitching rule until the stitching at the last long circular hole (3) is completed, and then the needle stitching of the stitching path is completed.

8. The stitch-forming method of claim 5, wherein, In step 4, in working condition two, if it is necessary to change the stitching track during the needle stitching process, the upper stitching template (102) is detached from the upper clamping template (101), and the lower stitching template (202) is detached from the lower clamping template (201); then, the upper stitching template (102) and the lower stitching template (202) with the same other stitching track are replaced and detachably installed on the upper clamping template (101) and the lower clamping template (201) respectively, and the subsequent needle stitching process is continued.

9. The stitch-forming method of claim 5, wherein, In step 4, in working condition three, if it is necessary to change the stitching track during the above needle stitching process, the upper stitching template (102) is detached from the upper clamping template (101), and the lower stitching template (202) is detached from the lower clamping template (201); then, the slider (9) with the same number of long circular holes (3) is replaced and slidably installed in the corresponding sliding groove (8) of the upper stitching template (102) and the lower stitching template (202) respectively, and the upper stitching template (102) and the lower stitching template (202) are detachably installed on the upper clamping template (101) and the lower clamping template (201) respectively, and the subsequent needle stitching process is continued.

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