A continuous yarn loop braiding device and a method for forming preforms.

Abstract

This application provides a continuous yarn circular braiding device and a method for preform forming, belonging to the field of composite material forming technology. It includes a mandrel, a drive mechanism, a yarn feeding mechanism, connectors, and a yarn feeding chute. The mandrel has ultra-low curvature variation surfaces and ultra-high curvature variation surfaces distributed on it. Below the mandrel is a yarn feeding mechanism and several connectors arranged in a ring relative to the mandrel. Warp yarns are connected between the connectors and the mandrel. The yarn feeding mechanism is assembled in the yarn feeding chute, and braided yarns are connected between the yarn feeding mechanism and the mandrel. The connection points of the warp yarns, braided yarns, and the mandrel are all close to the central axis of the mandrel. The yarn feeding mechanism is driven by the drive mechanism to move along the yarn feeding chute, causing the position of the braided yarns relative to the warp yarns to change, thus achieving the braided structure forming on the mandrel surface. The above device can realize the automated forming of preforms with ultra-low and ultra-high curvature variation surfaces.

Description

Technical Field

[0001] This application relates to a continuous yarn circular braiding device and a method for preform forming, belonging to the field of composite material forming technology. Background Technology

[0002] Three-dimensional braided composite materials possess excellent properties such as lightweight and high strength, good structural designability, and ease of forming complex components. They are widely used in aerospace, transportation, and military energy fields, including rocket throat liners, propeller blades, engine nozzles, missile nose cones, and carbon fiber vehicle frames. In contrast, two-dimensional braiding technology offers advantages such as low material loss and high automation, enabling the one-step forming of complex components and making it ideal for forming various curved surfaces and irregularly shaped structural parts.

[0003] While two-dimensional weaving technology can be applied to the automated forming of most irregular curved surfaces, it cannot stably form curved surfaces of extreme curvature, such as ultra-low (nearly planar) and ultra-high (nearly vertical) curvature. Traditional solutions involve weaving and yarn addition / subtraction processes to form preforms of surfaces with ultra-low and ultra-high curvature variations, but these methods are complex and have low automation. To address these issues, it is necessary to provide an innovative device and method that can simultaneously form preforms of surfaces with ultra-low and ultra-high curvature variations, overcoming the shortcomings of existing technologies. Summary of the Invention

[0004] In view of this, this application first provides a continuous yarn circular weaving device that can realize the automated forming of curved preforms with ultra-low (near planar) and ultra-high (near vertical) curvature variation characteristics.

[0005] Specifically, this application is implemented through the following scheme:

[0006] A continuous yarn circular braiding device includes a mandrel, a drive mechanism, a yarn feeding mechanism, a connector, and a yarn feeding chute.

[0007] The mandrel has ultra-low curvature variation surfaces and ultra-high curvature variation surfaces distributed on it.

[0008] A yarn feeding mechanism and several connectors are provided below the mandrel.

[0009] The connector is arranged in a ring relative to the mandrel, and warp yarns connect the connector and the mandrel.

[0010] The yarn feeding mechanism is assembled in the yarn feeding chute, and braided yarn is connected between the yarn feeding mechanism and the mandrel.

[0011] The connection points of the warp yarns, braided yarns, and mandrel are all located close to the central axis of the mandrel.

[0012] The yarn feeding mechanism is driven by a drive mechanism to move along the yarn feeding groove, causing the position of the braided yarn relative to the warp yarn to change, thereby forming the braided structure on the surface of the mandrel.

[0013] Furthermore, as a preferred option:

[0014] The ultra-low curvature variation surface is located near the central axis of the mandrel, while the ultra-high curvature variation surface is located near the outer edge of the mandrel.

[0015] The mandrel is fixed by a support mechanism, and a support plate is provided on the top of the support mechanism, on which the mandrel is fixed.

[0016] The drive mechanism is connected to the yarn feeding mechanism via a drive rod. More preferably:

[0017] The driving mechanism includes a gear frustum, with the driving rod fixedly connected to the outer wall of the gear frustum. A gear is provided on the inner wall of the gear frustum, meshing with the transmission gear of the servo motor. When the servo motor starts, it drives the transmission gear to rotate, and through the meshing action, it drives the gear frustum to rotate synchronously, which in turn drives the driving rod to rotate, causing the yarn feeding mechanism connected to the driving rod to rotate synchronously.

[0018] The yarn feeding mechanism includes a yarn beam, a yarn guide pulley, a yarn threading hole, and a support frame. The support frame is connected to the drive mechanism. The yarn beam is mounted on the support frame. A yarn guide pulley is positioned axially on the yarn beam, and a yarn threading hole is located above the yarn guide pulley. The braided yarn on the yarn beam is output through the yarn guide pulley and the yarn threading hole. More preferably, a slider and a drive stop are provided below the support frame to achieve a stable sliding connection between the yarn feeding mechanism and the yarn feeding chute. Specifically, the slider is located within the yarn feeding chute, and the drive stop is connected to the slider. The drive mechanism drives the drive stop to move, causing the slider to move along the yarn feeding chute, and the yarn feeding mechanism moves synchronously. A tension spring is provided between the yarn guide pulley and the yarn threading hole.

[0019] In the yarn feeding mechanism described above, the yarn is stored on the yarn beam. The support frame supports the yarn beam and ensures its rotation, while also raising the yarn feeding device to prevent interference with the connector. The drive stop lever cooperates with the drive rod (either through contact or fixed connection) to rotate the yarn feeding mechanism. The slider is located inside the yarn feeding groove to ensure that the yarn feeding mechanism does not jump out of the groove during rotation. The yarn guide pulley is located at the center of the yarn beam's axial direction, guiding and changing the yarn path and providing yarn tension. The tension spring's upper end is connected to the lower surface of the yarn threading hole, and its lower end is connected to the yarn guide pulley. The tension spring and the yarn guide pulley cooperate to control the yarn tension. The yarn threading hole controls the yarn exit position. The yarn beam retainer prevents the yarn beam from moving along its axial direction.

[0020] The yarn feeding chute has an ∞-shaped structure with the ends connected. The connector is located inside its structural ring. The yarn feeding mechanism moves along the outline of the yarn feeding chute, allowing the braided yarn to travel inside and outside the warp yarn to complete the braiding.

[0021] The applicant's second objective is to provide a method for forming a preform using the aforementioned continuous yarn circular braiding device, characterized by the following steps:

[0022] Step 1: Select the material, type, and linear density of the braided and warp yarns according to the performance requirements of the circular braided preform. Determine the warp density of the braided preform and select the parameters of the yarn feeding mechanism and drive mechanism based on the warp density.

[0023] The materials of the braided yarn and warp yarn can be high-performance fibers such as carbon fiber, quartz fiber and aramid fiber. The model of the braided yarn and warp yarn can be different models that determine the fiber performance, such as T300, T700 or T800. The linear density of the braided yarn and warp yarn can be parameters that determine the yarn thickness, such as 3K, 6K or 12K. The warp density of the braided preform refers to the number of braided yarns per centimeter along the warp direction, with a unit of 2 to 5 yarns / cm.

[0024] Step 2: The braided yarn is wound and installed onto the yarn feeding mechanism, with its free end fixed to the top of the mandrel; one end of the warp yarn is connected to the connector via elastic yarn, and the other end is fixed to the top of the mandrel.

[0025] Step 3: Start the servo motor and fine-tune and calibrate the servo motor speed according to the forming state of the ring-shaped braided preform. This will enable the automated batch stable production of braided preforms with fixed parameters.

[0026] This invention enables the automated forming of preforms with ultra-low (near planar) and ultra-high (near vertical) curvature variations. In this invention, a single braided yarn is interwoven with multiple warp yarns around a mandrel, thereby forming a continuous yarn ring-woven preform. The continuous yarn ring-woven device and method proposed in this invention can easily achieve the automated forming of preforms with ultra-low and ultra-high curvature variation characteristics, which helps to greatly reduce production costs while ensuring the quality of the preform. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a three-dimensional structural diagram of the present application;

[0029] Figure 2 This is a top view of the structure of this application (with the mandrel removed).

[0030] Figure 3 This is a schematic diagram of the mandrel structure in this application;

[0031] Figure 4 This is a schematic diagram showing the assembly relationship between the support mechanism and the drive mechanism.

[0032] Figure 5 This is a schematic diagram illustrating the assembly relationship between the base and the support in this application;

[0033] Figure 6 This is a schematic diagram of the yarn feeding mechanism in this application;

[0034] Figure 7 This is a diagram showing the forming state of the woven preform in this application.

[0035] Numbered in the diagram: 1. Mandrel; 11. Ultra-low curvature variation surface; 12. Ultra-high curvature variation surface; 13. Flat top; 2. Support mechanism; 21. Support plate; 22. Support base; 3. Drive mechanism; 31. Gear frustum; 32. Support frustum; 33. Drive rod; 34. Bearing; 4. Transmission gear; 41. Servo motor; 42. Connector; 5. Yarn feeding mechanism; 51. Yarn beam; 52. Drive stop; 53. Slider; 54. Yarn guide pulley; 55. Tension spring; 56. Yarn threading hole; 57. Yarn beam retainer; 58. Support frame; 6. Connector; 7. Base; 71. Yarn feeding groove; 72. Vertical support cylinder; 73. Sliding platform; A. Braided yarn; B. Warp yarn; C. Elastic yarn. Detailed Implementation

[0036] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the technical solutions in the embodiments of this application will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit the technical solutions of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0037] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be located directly or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to that other component. The terms "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or position based on the orientation or position shown in the accompanying drawings, and are only for ease of description and should not be construed as limiting the present technical solution.

[0038] Example 1

[0039] This embodiment describes a continuous yarn circular weaving device, combined with... Figure 1 , Figure 2 It includes a spindle 1, a support mechanism 2, a drive mechanism 3, a transmission gear 4, at least one yarn feeding mechanism 5, several connectors 6, and a base 7.

[0040] Combination Figure 3 The mandrel 1 has a pot-lid-shaped structure with a flat top 13 at its vertical central axis. Ultra-low curvature variation surfaces 11 are distributed around the outer periphery of the flat top 13. In this embodiment, the curvature variation of the ultra-low curvature variation surfaces 11 is approximately 2.38, almost constant, and close to a horizontal straight line. The outer edge of the mandrel 1 has an ultra-high curvature variation surface 12 with a curvature of approximately 178.17, changing rapidly and close to a vertical straight line. The overall structure transitions from ultra-low curvature variation to ultra-high curvature variation from top to bottom, with a quarter-ellipse cross-section. The maximum external dimensions (i.e., the outer edge) of the entire mandrel 1 are approximately 760 mm × 760 mm × 90 mm.

[0041] Combination Figure 4 The support mechanism 2 is provided with a support plate 21 at the top, which is adapted to the outer edge of the spindle 1 so that the spindle 1 is fixedly installed on the support plate 21; the support mechanism 2 is provided with a support base 22 at the bottom so that the support mechanism 2 and the spindle 1 on it are stably installed on the ground.

[0042] A servo motor 41 is mounted on the support mechanism 2 via a connector 42, and a transmission gear 4 is connected to the output shaft below the servo motor 41.

[0043] Combination Figure 5The drive mechanism 3 includes a gear frustum 31, a support frustum 32, and a drive rod 33. The support frustum 32 is mounted on the bottom of the support mechanism 2 via a bearing 34, and the gear frustum 31 is mounted on it. The drive rod 33 is fixedly connected to the outer wall of the gear frustum 31. A gear is mounted on the inner wall of the gear frustum 31, which meshes with the transmission gear 4. During use, the gear frustum 31 transmits the rotational kinetic energy of the motor. The support frustum 32 supports the gear frustum 31 and is connected to the bearing 34. The drive rod 33 is in contact with the drive stop rod 52. The rotation of the gear frustum 31 drives the yarn feeding mechanism 5 to rotate along the yarn feeding chute 71.

[0044] The base 7 has a circular structure and is located on the outer periphery of the drive mechanism 3 below the spindle 1. The base 7 includes a vertical support cylinder 72 and a sliding platform 73. The vertical support cylinder 72 has a circular structure, and the sliding platform 73 is mounted on the vertical support cylinder 72. A yarn feeding groove 71 is provided on the sliding platform 73, and the yarn feeding groove 71 is composed of two intersecting wavy lines, such as... Figure 1 The structure represented by the ∞ structure connected end to end is used as an example.

[0045] Both the yarn feeding mechanism 5 and the connector 6 are mounted on the base 7, but the connector 6 is fixed on the sliding platform 73, while the yarn feeding mechanism 5 is slidably mounted on the base 7 via the yarn feeding groove 71.

[0046] Combination Figure 4 , Figure 5 and Figure 6 The yarn feeding mechanism 5 includes a yarn beam 51, a drive stop 52, a slider 53, a yarn guide pulley 54, a tension spring 55, a yarn beam retainer 57, and a support frame 58. The drive stop 52 is inserted into the yarn feeding groove 71 and protrudes below the sliding platform 73. The drive rod 33 is below the sliding platform 73 and contacts the drive stop 52. The drive stop 52 and the drive rod 33 cooperate to rotate the yarn feeding mechanism 5. The slider 53 is located inside the yarn feeding groove 71 to ensure that the yarn feeding mechanism 5 will not jump out of the yarn feeding groove 71 during rotation. The support frame 58 is located on the drive stop 52 above the slider 53. The support frame 58 serves two purposes: firstly, it raises the yarn feeding device 5 to avoid interference with the connector 6; secondly, it... A yarn beam 51 supports and stores the yarn, ensuring that the yarn beam 51 can rotate. A horizontal U-shaped yarn beam retainer 57 is installed on the support frame 58 to prevent the yarn beam 51 from moving along its own axis. A yarn guide pulley 54 is installed on the side wall of the yarn beam retainer 57, and a yarn threading hole 56 is provided on the yarn beam retainer 57 above the yarn guide pulley 54. The yarn threading hole 56 controls the yarn lead-out position. The yarn guide pulley 54 is located at the center position of the yarn beam axis and is used to guide and change the yarn path and provide yarn tension. The lower end of the yarn guide pulley 54 is connected to a tension spring 55. The tension spring 55 cooperates with the yarn guide pulley 54 to control the yarn tension. The upper end of the tension spring 55 is connected to the lower surface of the yarn beam retainer 57 corresponding to the yarn threading hole 56.

[0047] When the above-mentioned continuous yarn loop braiding device is used for preform forming, the steps are as follows:

[0048] Step 1: Based on the performance requirements of the target object's circular braided preform, select the material, model, and linear density of the braided yarn A and warp yarn B, determine the warp density of the braided preform, and select the parameters of the yarn feeding mechanism 5 and the drive mechanism 3 based on the warp density.

[0049] Both the braided yarn A and the warp yarn B are made of T300 carbon fiber. The linear density of braided yarn A is 12K, the linear density of warp yarn B is 6K, and the warp density is 2.5 yarns / cm.

[0050] Step 2: The braided yarn A is wound onto the surface of the yarn beam 41 by the yarn winding machine and installed on the yarn feeding mechanism 5. Its free end passes through the yarn passing pulley 54 and the yarn passing hole 56 and is fixed to the top of the mandrel 1 (such as at the flat top 13). One end of the warp yarn B is connected to the connector 6 through the elastic yarn C (the elastic yarn C provides a certain elastic tension to the warp yarn B), and the other end is fixed to the top of the mandrel 1 (such as at the flat top 13).

[0051] Step 3: Start the servo motor 41. Fine-tune and calibrate the speed of the servo motor 41 according to the forming state of the woven preform. After the parameters are determined, the servo motor 41 drives the transmission gear 4 to rotate. This rotation is transmitted to the gear of the gear frustum 31 through the kneading action, causing the gear frustum 31 to rotate around the support mechanism 2. The drive rod 33 rotates synchronously, and through the drive stop rod 52 and the support frame 58, it drives the yarn feeding mechanism 5 to move. Under the limiting action of the slider 53 and the drive rod 33, the yarn feeding mechanism 5 moves along the yarn feeding groove 71. During this process, because the yarn feeding mechanism 5 moves along the yarn feeding groove 71, and the connector 6 is located in the ∞ ring structure, the woven yarn A is displaced relative to the warp yarn B. This achieves the automated batch stable production of woven preforms with fixed parameters, thus forming a woven preform like... Figure 7 The circular braided structure shown.

[0052] The above-described embodiments are merely illustrative of several feasible implementations of the present invention, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the present invention, nor are the embodiments intended to limit the scope of protection in the claims of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention. All equivalent implementations or changes that do not depart from the present invention should be included in the present invention.

Claims

1. A continuous yarn circular knitting device, characterized in that: It includes a mandrel, a drive mechanism, a yarn feeding mechanism, a connector, and a yarn feeding chute. The mandrel has a pot-lid-shaped structure with a flat top at its vertical central axis. The mandrel has ultra-low curvature variation surfaces and ultra-high curvature variation surfaces distributed on it. The ultra-low curvature variation surfaces are distributed near the outer periphery of the flat top, while the ultra-high curvature variation surfaces are located at the outer edge of the mandrel. A yarn feeding mechanism and several connectors are provided below the mandrel. The connector is arranged in a ring relative to the mandrel, and warp yarns connect the connector and the mandrel. The yarn feeding mechanism is assembled in the yarn feeding chute, and braided yarn is connected between the yarn feeding mechanism and the mandrel. The connection points of the warp yarns, braided yarns, and mandrel are all located close to the central axis of the mandrel. The yarn feeding mechanism is driven by a drive mechanism to move along the yarn feeding groove, causing the position of the braided yarn relative to the warp yarn to change, thereby realizing its braiding formation on the surface of the mandrel.

2. The continuous yarn circular knitting device according to claim 1, characterized in that: The mandrel is fixed by a support mechanism, and a support plate is provided on the top of the support mechanism, on which the mandrel is fixed.

3. The continuous yarn circular knitting device according to claim 1, characterized in that: The drive mechanism is connected to the yarn feeding mechanism via a drive rod.

4. A continuous yarn circular knitting device according to claim 3, characterized in that: The driving mechanism includes a gear frustum, a driving rod is fixedly connected to the outer wall of the gear frustum, and a gear is provided on the inner wall of the gear frustum, which meshes with the transmission gear of the servo motor. When the servo motor is started, it drives the transmission gear to rotate, and through the meshing action, it drives the gear frustum to rotate accordingly. The driving rod and the yarn feeding mechanism connected to the driving rod rotate synchronously.

5. A continuous yarn circular knitting device according to claim 1, characterized in that: The yarn feeding mechanism includes a yarn beam, a yarn guide pulley, a yarn threading hole, and a support frame. The support frame is connected to the drive mechanism. The yarn beam is mounted on the support frame. A yarn guide pulley is provided at the axial position of the yarn beam. A yarn threading hole is provided above the yarn guide pulley. The braided yarn on the yarn beam is output through the yarn guide pulley and the yarn threading hole.

6. A continuous yarn circular knitting device according to claim 5, characterized in that: Below the support frame, there is a slider and a drive stop. The slider is located in the yarn feeding groove, and the drive stop is connected to the slider. When the drive mechanism is started, the slider is moved along the yarn feeding groove via the drive stop, and the yarn feeding mechanism moves synchronously.

7. A continuous yarn circular knitting device according to claim 5, characterized in that: A tension spring is provided between the yarn guide pulley and the yarn threading hole.

8. A continuous yarn circular knitting device according to claim 1, characterized in that: The yarn feeding chute has an ∞-shaped structure with the ends connected. The connector is located inside its structural ring. The yarn feeding mechanism moves along the outline of the yarn feeding chute, allowing the braided yarn to travel inside and outside the warp yarn to complete the braiding.

9. A method for forming a preform using the continuous yarn loop braiding device of claim 1, characterized in that, The steps are as follows: Step 1: Select the specifications of the braiding yarn and warp yarn according to the performance requirements of the circular braided preform, determine the warp density of the braided preform, and select the parameters of the yarn feeding mechanism and drive mechanism based on the warp density. The braided yarn and warp yarn are any one of carbon fiber, quartz fiber, and aramid fiber. Step two: The braided yarn is wound and installed onto the yarn feeding mechanism, with its free end fixed to the top of the mandrel; one end of the warp yarn is connected to the connector via elastic yarn, and the other end is fixed to the top of the mandrel. Step 3: Start the servo motor and fine-tune and calibrate the servo motor speed according to the forming state of the ring-woven preform. This enables the automated batch stable production of woven preforms with fixed parameters.

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