Continuous fiber reinforced polymer forming device and forming method with adjustable stiffness

Abstract

The present invention relates to a forming device and forming method for a continuous fiber reinforced polymer with adjustable stiffness, wherein the forming device for a continuous fiber reinforced polymer with adjustable stiffness is characterized by comprising a planetary gear set, a center frame (10) passing through the center of the planetary gear set, and a heating mold (1) arranged below the planetary gear set and capable of allowing the center frame (10) to pass through, wherein a feeding pipe (3) for feeding polymer particles (4) into the heating mold (1) is connected to the side of the heating mold (1); the present invention uses the center frame on which the fibers are wound as a support material, and by adjusting the rotation speed of the planetary gear, changes in the weaving effects of the fibers on the center frame, such as continuous dense weaving, interlaced sparse weaving, staggered sparse weaving, and gradient weaving, are achieved, thereby adjusting the stiffness of the polymer wire, especially the change in the bending stiffness. The present invention is suitable for processing variable stiffness polymer structures that require adjustment of the wire stiffness.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber reinforced polymer forming and manufacturing, and in particular relates to a forming device and a forming method for continuous fiber reinforced polymer with adjustable stiffness. Background Art

[0002] Generally speaking, continuous fiber reinforced polymer is a composite material structure formed by using high-strength continuous fibers as the reinforcing phase and embedding them into a polymer matrix. This type of material can significantly improve the overall tensile strength and stiffness of the polymer matrix due to the excellent unidirectional tensile properties of the fibers, and has been widely used in aerospace, automobiles, sports equipment and other fields.

[0003] However, the continuous fiber reinforced polymers in the existing technology have obvious limitations in their applications. Although their tensile mechanical properties along the fiber axis are excellent, their bending resistance is generally low, especially when they need to withstand non-axial or complex bending loads. They often show inadequacy. This means that traditional continuous fiber reinforced polymers are mainly suitable for simple structures that bear high axial loads, such as the circumferential winding application of high-pressure hydrogen storage tanks, and their applicability is limited to components that require excellent bending resistance.

[0004] More importantly, in many complex industrial applications, engineering materials are not only required to have good tensile properties, but also have high requirements for bending properties, and often require their properties to be able to achieve variable or continuous gradient changes, for example:

[0005] 1. Compound bow limbs: During the stretching and releasing process, the stress characteristics of different parts of the limb are significantly different. The bending resistance of the material needs to gradually decrease from the middle section to the ends to achieve the best energy storage and release efficiency.

[0006] 2. Wind turbine blades: The root of the blade needs to withstand huge torque and bending loads, so high tensile strength and high bending stiffness are required; while the tip of the blade needs higher flexibility to adapt to wind load changes and reduce vibration, which requires the stiffness of the blade material to show a continuous gradient change along the length direction;

[0007] 3. UAV frames and other lightweight structures: For these structures, it is usually necessary to precisely control the stiffness and flexibility of local areas while ensuring the overall structural strength to adapt to different functional requirements or optimize energy absorption;

[0008] 4. Flexible robots: In the fields of flexible robots and wearable devices, it is necessary to maintain flexibility in the non-stressed state to adapt to environmental changes; and under working conditions such as load-bearing or precise positioning, it is necessary to have high local stiffness for support. Traditional rigid structures are difficult to meet both requirements at the same time. The material itself needs to have variable stiffness to achieve coordinated optimization of motion control and force support.

[0009] 5. Sole components: In the sole design, the arch area requires higher stiffness to support the body weight and maintain the foot structure, while the forefoot and heel areas need to be flexible enough to cushion the impact and improve comfort. If the sole material has adjustable stiffness performance, it can achieve optimized support and shock absorption functions according to different foot areas, thereby improving the wearing experience and sports performance.

[0010] Currently, the fibers of continuous fiber-reinforced polymers prepared by traditional methods are uniform and fixed, resulting in the mechanical properties of the material (especially bending stiffness) being relatively uniform and unadjustable throughout the entire component. This single, unadjustable stiffness characteristic makes existing materials unable to effectively meet the above-mentioned industrial applications that have clear requirements for stiffness adjustment, especially bending stiffness. Summary of the Invention

[0011] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a continuous fiber reinforced polymer forming device and forming method with adjustable stiffness. The continuous fiber reinforced polymer forming device with adjustable stiffness is reasonably designed and can be used for the continuous production of fiber reinforced polymers with adjustable bending stiffness.

[0012] In order to achieve the above object, the technical solution adopted by the present invention is:

[0013] A continuous fiber reinforced polymer forming device with adjustable stiffness, characterized by comprising a planetary gear set, a center frame passing through the center of the planetary gear set, and a heating mold located below the planetary gear set and capable of passing the center frame. A feed pipe for conveying polymer particles into the heating mold is connected to the side of the heating mold.

[0014] The planetary gear set includes a fixed sun gear, three planetary gears that can move relative to the sun gear, and a ring gear. The ring gear is meshed with a drive gear for transmission. The output end of the drive motor is connected to the drive gear. The center of the sun gear has a sun gear center hole. The center frame passes through the sun gear center hole. Each planetary gear is provided with a wire drum that can rotate around its own axis. The wire drum is wound with fiber. The fiber passes downward through the center hole of the planetary gear and is wound around the center frame.

[0015] A center frame wound with three fibers and polymer particles transported by a feed pipe are melted in a heated mold and formed, and continuous fiber-reinforced polymer is output from the bottom of the heated mold. The density of the fibers wound on the center frame in the axial direction is adjusted by adjusting the speed of the drive motor to adjust the bending stiffness of the output continuous fiber-reinforced polymer in different axial areas.

[0016] Preferably, radial protrusions protruding from the outer surface of the center frame are arranged along the axial and circumferential directions on the outer surface of the center frame for enhancing the bending stiffness performance of the output continuous fiber reinforced polymer and for limiting the fibers.

[0017] Preferably, the radial protrusion is a buckle protruding from the outer surface of the center frame, and the buckle consists of a hemispherical base and a straight groove or a cross groove on the hemispherical base, and the groove of the straight groove or the cross groove is used to limit the fiber.

[0018] Preferably, the hemispherical base has a threaded column on the side away from the slot or the cross groove, and the threaded column is threadedly connected to the threaded countersunk hole arranged on the outer surface of the center frame. The slot or the cross groove can be rotated and adjusted in the circumferential direction of the hemispherical base so that the fiber can sink into the groove of the slot or the cross groove when it is wound to the corresponding position.

[0019] Preferably, the radial protrusions are strip-shaped protruding ribs radially arranged on the outer surface of the center frame, and the outer edges of the protruding ribs have corrugated grooves for limiting the fibers so that the fibers can sink into the grooves of the corrugated grooves when they are wound to the corresponding positions.

[0020] Preferably, a forming cavity is provided in the center of the above-mentioned heating mold, a heating rod is installed on one side of the forming cavity, and the other side of the forming cavity is connected to the feeding pipe. A feeding funnel is installed on the upper part of the feeding pipe, and the polymer particles are transported into the forming cavity from the feeding funnel and the feeding pipe.

[0021] Preferably, three circumferentially evenly arranged conveying wheels are provided below the heating mold and beside the continuously output continuous fiber reinforced polymer, and the conveying wheels are tightly attached to the outer wall surface of the continuous fiber reinforced polymer.

[0022] Preferably, a cutting knife for cutting the continuous fiber reinforced polymer is provided between the heating mold and the conveying wheel.

[0023] The present invention provides a method for forming a continuous fiber reinforced polymer with adjustable stiffness, characterized in that the method comprises the following steps using the above-mentioned forming device for continuous fiber reinforced polymer with adjustable stiffness:

[0024] Step S1: One end of the fiber passes through the center hole of the planetary gear and is solidified in the solidified polymer, while the other end is wound on the bobbin; the center frame passes through the center hole of the sun gear, and the lower end is also solidified in the solidified polymer; the sun gear in the planetary gear set remains fixed, and the drive motor drives the ring gear to rotate through the drive gear, thereby driving the planetary gears to rotate; the planetary gears drive the fiber to spirally wind around the center frame that continues to move downward;

[0025] Step S2: By adjusting the speed of the driving motor, the fibers have different weaving densities on the center frame. As the speed of the driving motor increases from low to high, the speed of the corresponding planetary gear increases from low to high, thereby achieving the weaving effects of continuous dense weaving, alternate row sparse weaving, and staggered row sparse weaving of the fibers on the center frame.

[0026] Step S3: The polymer particles are fed into the forming cavity of the heated mold through a feeding funnel and a feeding tube. Under the heating of the heating rod, the polymer particles in the forming cavity are melted and then solidified into a solidified polymer. The center frame wrapped with fibers and the solidified polymer together form a continuously output continuous fiber reinforced polymer. Due to the different weaving densities of the fibers in the axial direction of the center frame, continuous fiber reinforced polymers with different bending stiffness can be formed in different axial regions.

[0027] Preferably, three circumferentially evenly arranged conveying wheels are provided below the above-mentioned heating mold and beside the continuously output continuous fiber reinforced polymer. A cutting knife for cutting the continuous fiber reinforced polymer is provided between the heating mold and the conveying wheel. As the conveying wheel rolls, the continuous fiber reinforced polymer is continuously pulled downward and cut by the cutting knife when needed.

[0028] Compared with the existing technology, the present invention has the following effects: the present invention is reasonably designed and provides a forming technology that can accurately control the fiber weaving density, thereby achieving the stiffness of polymer wires (composite materials), especially the continuous adjustment and gradient change of the bending stiffness in different areas along the length direction of the wire.

[0029] Through the combination of the center frame, continuous fiber and polymer, it is possible to improve the axial tensile strength of the polymer wire while ensuring the bending strength of the polymer wire; at the same time, the continuous fiber reinforced polymer realizes different weaving densities of the continuous fiber on the center frame through the different rotation speeds of the planetary gear and the ring gear, and combined with the curing and strengthening of the polymer, the stiffness of the polymer wire in different axial areas can be adjusted.

[0030] The present invention focuses on solving the problem that traditional polymer wires only have good tensile strength but poor bending stiffness and cannot be adjusted. The device and method proposed in the present invention have the following significant advantages over the existing technology:

[0031] 1. Achieving adjustable and gradient bending stiffness of the material (wire) along its length (axial direction): This is the core advantage of this invention. Conventional fiber-reinforced polymers have fixed stiffness and poor bending resistance. However, by precisely controlling the fiber braid density, this invention enables the production of continuous fiber-reinforced polymers with varying stiffness, particularly adjustable and gradient bending stiffness.

[0032] 2. Significantly improve the flexural performance of composite materials: By introducing a center frame as a support material and combining it with fiber winding, the flexural strength of polymer wires can be effectively improved, solving the limitation of existing technologies that continuous fiber-reinforced polymers have excellent tensile properties but insufficient flexural properties.

[0033] 3. Expanding the scope of material applications: The material has adjustable stiffness (especially adjustable bending stiffness), which enables it to better meet industrial applications with complex and dynamic requirements for mechanical properties, such as:

[0034] Compound bow limbs: achieve a gradual decrease in stiffness along the length to optimize energy storage and release;

[0035] Wind turbine blades: The gradient requirements of high stiffness at the root and high flexibility at the tip of the blade are achieved;

[0036] The drone frame and lightweight structure precisely regulate local stiffness and flexibility to adapt to different functional requirements.

[0037] Flexible robots and wearable devices: maintain compliance when not under stress and provide local stiffness support when under stress;

[0038] Sole components: Optimize support and shock absorption according to the needs of different areas of the foot.

[0039] 4. Improve the freedom of material design: According to the specific application scenario and force requirements, the mechanical property distribution of the material can be customized by adjusting the weaving parameters, realizing the design concept of "combining rigidity and flexibility".

[0040] 5. Accurate and reliable process control: Through real-time dynamic adjustment of the drive motor speed, the precise control of the fiber winding density is ensured, thereby ensuring the repeatability and stability of the final product performance.

[0041] 6. Reasonable structure and good production continuity: The device is reasonably designed, integrating the links of fiber winding, polymer melting and solidification, wire pulling and cutting, which is conducive to continuous production and improves production efficiency.

[0042] In summary, the present invention achieves gradient adjustment of the bending stiffness of continuous fiber reinforced polymer components through an innovative center frame and planetary gear structure, filling a gap in the existing technology and having important engineering application prospects and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the forming device and continuous dense weaving of fibers;

[0044] Figure 2 It is a schematic diagram of the forming device and the interlaced weaving of fibers;

[0045] Figure 3 This is a schematic diagram of the forming device and the staggered weaving of fibers;

[0046] Figure 4 is a schematic diagram of the forming device and fiber gradient weaving;

[0047] Figure 5 is a top view schematic diagram of the planetary gear set and drive mechanism;

[0048] Figure 6 It is a schematic diagram of the center frame and continuous fiber reinforced polymer structure;

[0049] Figure 7 It is a side view of the center frame;

[0050] Figure 8 It is a top view of the center frame;

[0051] Figure 9 This is the effect diagram of continuous dense winding of center frame fibers;

[0052] Figure 10 This is the effect diagram of the center frame fiber interlaced woven winding;

[0053] Figure 11 This is the effect diagram of the center frame fiber interlaced woven winding;

[0054] Figure 12 This is the effect diagram of the center frame fiber gradient weaving winding;

[0055] Figure 13 It is a side view of the center frame of the convex rib;

[0056] Figure 14 This is the effect diagram of the continuous dense winding of the fibers on the center frame of the convex rib.

[0057] In the figure: 1. Heating mold, 2. Heating rod, 3. Feeding tube, 31. Feeding funnel, 4. Polymer particles, 41. Cured polymer, 5. Driving motor, 51. Driving gear, 6. Ring gear, 61. Internal teeth, 62. External teeth, 7. Planetary gear, 71. Center hole, 8. Sun gear, 81. Center hole of sun gear, 9. Wire drum, 10. Center frame, 11. Radial protrusion, 11A, buckle, 11B, convex rib, 111, hemispherical base, 112, cross groove, 113, corrugated groove, 12. Fiber, 121, continuous dense weave, 122, interlaced sparse weave, 123, staggered sparse weave, 124, gradient weave, 13. Continuous fiber reinforced polymer, 14. Conveying wheel, 15. Cutting knife, 16. Forming cavity. DETAILED DESCRIPTION

[0058] The present invention is further explained below with reference to specific embodiments and accompanying drawings.

[0059] like Figure 1-14 As shown, the forming device and forming method of the continuous fiber reinforced polymer with adjustable stiffness of the present invention can utilize the change in the rotation speed of the planetary gear in the device to achieve different effects of continuous fiber winding on the center frame, such as continuous dense weaving, interlaced sparse weaving, staggered sparse weaving, and gradient weaving. Through the different weaving densities of the fibers on the center frame, the continuous fiber reinforced polymer has different stiffness in the length direction or axial direction of the wire forming, especially different bending stiffness.

[0060] The forming device specifically includes a planetary gear set, a center frame 10 passing through the center of the planetary gear set, and a heating mold 1 arranged below the planetary gear set and allowing the center frame 10 to pass through. The side of the heating mold 1 is connected to a feeding pipe 3 for conveying polymer particles 4 into the heating mold 1.

[0061] The planetary gear set includes a sun gear 8, three planetary gears 7 and a ring gear 6. The output end of the drive motor 5 is connected to the drive gear 51, and the drive gear 51 and the ring gear 6 are meshed. The ring gear 6 has internal teeth 61 and external teeth 62. The external teeth 62 are meshed with the drive gear 51, and the internal teeth 61 are meshed with the planetary gears 7. The three planetary gears 7 are meshed with the sun gear 8 at the same time. The modules of the internal teeth 61 of the sun gear 8, the planetary gears 7 and the ring gear 6 are equal.

[0062] There is a sun gear center hole 81 in the center of the sun gear 8, and the center frame 10 passes through the sun gear center hole 81; each planet gear 7 is provided with a wire drum 9, and the wire drum 9 is wound with fiber 12, and the wire drum 9 can rotate around its own axis; that is, the wire drum 9 is placed on the planet gear 7 and rotates around the sun gear 8 together with the planet gear 7, and the fiber 12 passes downward through the center hole 71 of the planet gear 7 and is wound around the outer periphery of the center frame 10.

[0063] The center of the heating mold 1 has a forming cavity 16, one side of the forming cavity 16 is installed with a heating rod 2, and the other side is connected to the feeding pipe 3. A feeding funnel 31 is installed on the upper part of the feeding pipe 3, and the polymer particles 4 are transported into the forming cavity 16 from the feeding funnel 31 and the feeding pipe 3. Under the heating action of the heating rod, the center frame 10 wrapped with three fibers 12 and the polymer particles 4 transported by the feeding pipe 3 are melted and formed in the forming cavity 16 of the heating mold 1, and the formed continuous fiber reinforced polymer 13 is output from the lower side of the forming cavity 16. Three circumferentially evenly arranged conveying wheels 14 are tightly attached to the outer wall surface of the continuous fiber reinforced polymer 13. Under the continuous rotation of the conveying wheels 14, continuous power is provided for the continuous fiber reinforced polymer 13 to move downward. The cutting knife 15 is located on the lower side of the forming cavity 16 and is used to cut the continuous fiber reinforced polymer 13.

[0064] On the outer surface of the center frame 10, a number of radial protrusions 11 protruding from the outer surface of the center frame 10 are arranged along its axial and circumferential directions. Since the radial protrusions 11 protrude in the radial direction of the center frame, on the one hand, they can enhance the bending stiffness performance of the continuous fiber reinforced polymer 13. On the other hand, the radial protrusions 11 can also be used to limit the fibers 12 to ensure the relative position of the fibers 12 and the center frame 10.

[0065] One embodiment, such as Figure 6-12 As shown, the radial protrusion 11 is a buckle 11A protruding from the outer surface of the center frame 10. The buckle 11A consists of a hemispherical base 111 and a straight groove or a cross groove 112 on the hemispherical base 111. The diameter of the hemispherical base 111 is approximately the radius of the center frame. The groove of the straight groove or the cross groove 112 is used to limit the fiber 12. The hemispherical base 111 is in a spherical crown shape, the groove of the straight groove is in the shape of an "I", and the groove of the cross groove is in the shape of a "X". The groove of the straight groove or the cross groove 112 penetrates to the outer edge of the hemispherical base 111.

[0066] There are three rows of clips 11A around the center frame 10, which are arranged circumferentially. The clips 11A are mainly used to allow the fibers 12 to be wound around the center frame 10 with a certain degree of tightness and to keep the fibers 12 as far away from the center of the center frame as possible, so as to improve the stiffness of the polymer.

[0067] The hemispherical base 111 has a threaded column on the side away from the slot or cross groove 112, which is threadedly connected to the threaded countersunk hole arranged on the outer surface of the center frame 10. The slot or cross groove 112 can be rotated and adjusted in the circumferential direction of the hemispherical base 111, that is, the screw can be rotated relative to the threaded hole, so that the fiber 12 can be sunk into the groove of the slot or cross groove 112 when it is wound to the corresponding position. Due to the different pitches of different fibers on the center frame, the angles between the fibers and the axis of the center frame are different. By pre-adjusting the rotation angle of the hemispherical base 111, each fiber can be sunk into the groove of the slot or cross groove 112, thereby ensuring the relative position of the fiber and the center frame.

[0068] In another embodiment, the radial protrusion 11 is a rectangular protrusion rib 11B radially arranged on the outer surface of the center frame 10, that is, 2-6 groups of protrusion ribs 11B are provided in the circumferential direction of the center frame 10. Figure 13-14 There are 4 groups of examples. The length direction of the convex rib 11B is consistent with the axial direction of the center frame. The width of the convex rib 11B is one-half to one-quarter of the diameter of the center frame. The thickness of the convex rib 11B is about one-fifth of the diameter of the center frame. The outer edge of the convex rib 11B has a corrugated groove 113 for limiting the fiber 12, so that the fiber 12 can sink into the groove of the corrugated groove 113 when it is wound to the corresponding position, ensuring the relative position of the fiber and the center frame. This embodiment does not require pre-installation and adjustment of the rotation angle of the hemispherical base 111, so that the production and manufacturing of the center frame is convenient and quick. The corrugated groove 113 is used instead of the serrated groove to avoid the fiber being cut off.

[0069] The ribs 11B are mainly used to allow the fibers 12 to be wound around the center frame 10 with a certain degree of tightness and to keep the fibers 12 as far away from the center of the center frame as possible, thereby improving the stiffness of the polymer.

[0070] The material of the above-mentioned center frame 10 can be a high-strength material such as metal, ceramic or PEEK (polyetheretherketone); the material of the fiber 12 can be natural fiber such as carbon fiber, glass fiber or metal fiber; the material of the polymer particles 4 can be thermoplastic and thermosetting resin materials such as ABS, PLA, PC, TPU, PETG, PEEK, etc.

[0071] The workflow of the present invention is as follows:

[0072] Step S1: One end of the fiber 12 passes through the center hole 71 of the planetary gear 7 and is solidified in the solidified polymer 41, and the other end is wound on the bobbin 9. The center frame 10 passes through the center hole 81 of the sun gear, and the lower end is also solidified in the solidified polymer 41; the sun gear 8 in the planetary gear set remains fixed, and the drive motor 5 drives the ring gear 6 to rotate through the drive gear 51, thereby driving the planetary gear 7 to rotate, and the planetary gear 7 drives the fiber 12 to be wound on the outer surface of the center frame 10 or on the radial protrusion 11.

[0073] Step S2 : By adjusting the rotation speed of the driving motor 5 , the fibers 12 can have different weaving densities on the center frame 10 .

[0074] like Figures 9-12 As shown, according to the rotation speed of the driving motor 5 from low to high and the corresponding rotation speed of the planetary gear 7 from low to high, the weaving effects of continuous dense weaving 121, interlaced sparse weaving 122, and staggered sparse weaving 123 can be achieved in sequence. By dynamically adjusting the rotation speed of the driving motor 5 in real time, the effect of gradient weaving 124 can also be achieved.

[0075] Step S3: The polymer particles 4 are fed into the forming cavity 16 of the heated mold 1 through the feeding funnel 31 and the feeding pipe 3. Figure 6 As shown, under the heating of the heating rod 2, the polymer particles 4 in the forming cavity 16 are melted and then solidified into a solidified polymer 41. The central frame 10 wrapped with the fibers 12 and the solidified polymer 41 together form a continuous fiber reinforced polymer 13; through the different weaving densities of the fibers 12 in the axial direction of the central frame 10, continuous fiber reinforced polymers 13 with different stiffness, especially different bending stiffness, can be formed.

[0076] Step S4: The continuous fiber reinforced polymer 13 is continuously pulled downward by the rolling of the conveying wheel 14 and is cut by the cutting knife 15 when needed.

[0077] The forming device and forming method of the continuous fiber-reinforced polymer with adjustable stiffness of the present invention can greatly improve the bending resistance of the fiber-reinforced polymer by introducing a center frame; at the same time, by controlling the rotation speed of the planetary gear and utilizing the radial protrusions on the center frame, different weaving densities of the continuous fibers can be achieved, and the bending resistance of the fiber-reinforced polymer can be adjusted, thereby greatly expanding the application scenarios of the fiber-reinforced polymer.

[0078] Further expansion will be made to methods such as winding continuous fibers close to the center frame, winding multiple strands inside the planetary gear, and adjusting the periodic change of the center frame diameter by the size of the buckle, so as to achieve a rich variety of stiffness changes.

[0079] The advantages of the present invention are:

[0080] (1) Planetary gear system achieves variable weaving density:

[0081] The innovative fiber winding mechanism based on a planetary gear set (the sun gear is fixed, the drive motor drives the ring gear to rotate, and then drives the planetary gears to rotate) is introduced.

[0082] By adjusting the driving motor (controlling the rotation speed of the planetary gear), the winding density of the fiber 12 on the center frame 10 can be controlled.

[0083] This is a core innovation that distinguishes it from traditional fixed winding or laying processes and is the key to achieving "stiffness adjustment" of materials.

[0084] (2) Center frame design as support and forming framework:

[0085] A center frame 10 with an annular array of distributed buckles 11A, consisting of a hemispherical base 111 and a cross groove 112, or a rectangular convex rib 11B is proposed and designed as a support material for fiber winding and a skeleton for the final wire.

[0086] The design of the center frame works closely with the winding mechanism of the planetary gear, allowing the fibers to be wound and consolidated stably and controllably to form a structure with a reinforcing effect.

[0087] (3) Diverse weaving effects and gradient weaving capabilities:

[0088] By adjusting the speed of the driving motor, a variety of fiber weaving effects can be flexibly achieved, including continuous dense weaving 121, interlaced sparse weaving 122, and staggered sparse weaving 123;

[0089] Furthermore, by dynamically adjusting the speed of the drive motor in real time, gradient weaving of the fibers can be achieved 124 , which means that the properties of the material can be adjusted continuously or in segments along its length or in local areas, greatly expanding the freedom of material design.

[0090] (4) Integrated forming and curing:

[0091] The fiber winding and polymer particle (or powder) feeding, heating, melting, and solidification processes are integrated into one device to form continuous fiber-reinforced polymer wires, which realizes efficient continuous production.

[0092] The above is only a preferred embodiment of the present invention. Without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A continuous fiber reinforced polymer forming device with adjustable stiffness, characterized by: The invention comprises a planetary gear set, a center frame (10) passing through the center of the planetary gear set, and a heating mold (1) arranged below the planetary gear set and capable of allowing the center frame (10) to pass through. A feeding pipe (3) for conveying polymer particles (4) into the heating mold (1) is connected to the side of the heating mold (1); The planetary gear set comprises a fixed sun gear (8), three planetary gears (7) capable of relative movement around the sun gear (8), and a ring gear (6). The ring gear (6) is meshed with a driving gear (51) for transmission. The output end of the driving motor (5) is connected to the driving gear (51). The center of the sun gear (8) has a sun gear center hole (81). The center frame (10) passes through the sun gear center hole (81). Each planetary gear (7) is provided with a wire drum (9) capable of rotating around its own axis. The wire drum (9) is wound with a fiber (12). The fiber (12) passes downward through the center hole (71) of the planetary gear (7) and is wound around the center frame (10). A center frame (10) wound with three fibers (12) and polymer particles (4) transported by a feed pipe (3) are melted and formed in a heated mold (1), and a continuous fiber-reinforced polymer (13) is output from the bottom of the heated mold (1). The density of the fibers (12) wound on the center frame (10) in the axial direction is adjusted by adjusting the rotation speed of the driving motor (5), so as to adjust the bending stiffness of the output continuous fiber-reinforced polymer (13) in different axial regions.

2. The continuous fiber reinforced polymer forming device with adjustable stiffness according to claim 1, characterized in that: The outer surface of the center frame (10) is provided with radial protrusions (11) along its axial and circumferential directions, which protrude from the outer surface of the center frame (10) for enhancing the bending stiffness performance of the output continuous fiber reinforced polymer (13) and for limiting the fibers (12).

3. The continuous fiber reinforced polymer forming device with adjustable stiffness according to claim 2, characterized in that: The radial protrusion (11) is a buckle (11A) protruding from the outer surface of the center frame (10), and the buckle (11A) is composed of a hemispherical base (111) and a straight groove or a cross groove (112) on the hemispherical base (111), and the groove of the straight groove or the cross groove (112) is used to limit the fiber (12).

4. The continuous fiber reinforced polymer forming device with adjustable stiffness according to claim 3, characterized in that: The hemispherical base (111) has a threaded column on one side away from the slot or cross slot (112), and the threaded column is threadedly connected to a threaded countersunk hole arranged on the outer surface of the center frame (10). The slot or cross slot (112) can be rotated and adjusted in the circumferential direction of the hemispherical base (111) so that the fiber (12) can be sunk into the groove of the slot or cross slot (112) when it is wound to the corresponding position.

5. The continuous fiber reinforced polymer forming device with adjustable stiffness according to claim 2, characterized in that: The radial protrusion (11) is a strip-shaped protruding rib (11B) radially arranged on the outer surface of the center frame (10), and the outer side of the protruding rib (11B) has a corrugated groove (113) for limiting the fiber (12), so that the fiber (12) can sink into the groove of the corrugated groove (113) when it is wound to the corresponding position.

6. The continuous fiber reinforced polymer forming device with adjustable stiffness according to claim 2, 3, 4 or 5, characterized in that: A forming cavity (16) is provided at the center of the heating mold (1), a heating rod (2) is installed on one side of the forming cavity (16), and the other side of the forming cavity (16) is connected to the feeding pipe (3), a feeding funnel (31) is installed on the upper part of the feeding pipe (3), and polymer particles (4) are transported into the forming cavity (16) through the feeding funnel (31) and the feeding pipe (3).

7. The continuous fiber reinforced polymer forming device with adjustable stiffness according to claim 6, characterized in that: Three circumferentially evenly arranged conveying wheels (14) are provided below the heating mold (1) and beside the continuously output continuous fiber reinforced polymer (13), and the conveying wheels (14) are tightly attached to the outer wall surface of the continuous fiber reinforced polymer (13).

8. The continuous fiber reinforced polymer forming device with adjustable stiffness according to claim 7, characterized in that: A cutting knife (15) for cutting the continuous fiber reinforced polymer (13) is provided between the heating mold (1) and the conveying wheel (14).

9. A method for forming a continuous fiber reinforced polymer with adjustable stiffness, characterized in that: Using the continuous fiber reinforced polymer forming device with adjustable stiffness as claimed in any one of claims 1 to 8 comprises the following steps: Step S1: One end of the fiber (12) passes through the center hole (71) of the planetary gear and is solidified in the solidified polymer (41), and the other end is wound in the wire drum (9); the center frame (10) passes through the center hole (81) of the sun gear, and the lower end is also solidified in the solidified polymer (41); the sun gear (8) in the planetary gear set remains fixed, and the drive motor (5) drives the ring gear (6) to rotate through the drive gear (51), thereby driving the planetary gear (7) to rotate; the planetary gear (7) drives the fiber (12) to be spirally wound on the center frame (10) that continues to move downward; Step S2: by adjusting the rotation speed of the driving motor (5), the fibers (12) have different weaving densities on the center frame (10), and according to the rotation speed of the driving motor (5) from low to high, the rotation speed of the corresponding planetary gear (7) from low to high, the weaving effects of continuous dense weaving (121), interlaced sparse weaving (122), and staggered sparse weaving (123) of the fibers (12) on the center frame (10) are achieved in sequence; Step S3: The polymer particles (4) are fed into the forming cavity (16) of the heating mold (1) through the feeding funnel (31) and the feeding tube (3). Under the heating of the heating rod (2), the polymer particles (4) in the forming cavity (16) are melted and then solidified into a solidified polymer (41). The center frame (10) wound by the fibers (12) and the solidified polymer (41) together form a continuously output continuous fiber reinforced polymer (13). Due to the different weaving densities of the fibers (12) in the axial direction of the center frame (10), continuous fiber reinforced polymers (13) with different bending stiffness can be formed in different areas in the axial direction.

10. The method for forming a continuous fiber reinforced polymer with adjustable stiffness according to claim 9, characterized in that: Three circumferentially evenly arranged conveying wheels (14) are provided below the heating mold (1) and beside the continuously output continuous fiber reinforced polymer (13). A cutting knife (15) for cutting the continuous fiber reinforced polymer (13) is provided between the heating mold (1) and the conveying wheels (14). As the conveying wheels (14) roll, the continuous fiber reinforced polymer (13) is continuously pulled downward and cut by the cutting knife (15) when needed.

Images