A dynamic variable diameter needle winding device

Abstract

This application relates to a dynamic variable diameter needle coil and a winding device. The dynamic variable diameter needle coil includes: a needle holder; an outer needle group comprising multiple outer needles, all of which are slidably disposed on the needle holder; a first opening and closing mechanism, which is convexly connected to the multiple outer needles and drives the multiple outer needles to move closer or further apart; an inner needle group disposed between the multiple outer needles, the inner needle group including two clamping ends, the two clamping ends being slidably disposed close to or far apart on the needle holder; and a second opening and closing mechanism, which is convexly connected to at least one of the clamping ends to drive the clamping end to slide. This application facilitates winding by setting the inner needle group to clamp the material strip, and by enlarging the diameter of the outer needle group before winding and reducing the diameter of the outer needle group when removing the needles, so as to leave a needle removal gap between the outer needle group and the battery cell, making it easy to remove the needles from the battery cell, and the removal process is less likely to cause defects such as core pulling or powder shedding from the battery cell.

Description

Technical Field

[0001] This application relates to the field of needle winding technology, and in particular to a dynamic variable diameter needle winding device and winding equipment. Background Technology

[0002] Currently, winding is a crucial step in battery production and processing. It involves placing the material strip on a winding needle, which then winds the strip as the needle rotates to form a battery cell.

[0003] In related technologies, the split-type winding needle design uses two separate winding needles to clamp the material strip, so as to fix the ends of the diaphragm and electrode. During the subsequent winding process, the material strip is less likely to move relative to the winding needle, thus the winding is tighter and the winding effect is better.

[0004] After winding, the material strip is tightly wrapped around the winding needle and clamped between two separate winding needles, making it difficult to pull the winding needle out of the formed battery cell. Furthermore, pulling the needle can easily cause defects such as battery cell pull-out and powder shedding. Summary of the Invention

[0005] This application provides a dynamic variable diameter winding needle and winding equipment to solve the technical problem in the related art that the needle pulling process can easily cause defects such as cell pulling and powder shedding, which affect the quality of cell forming.

[0006] Firstly, a dynamic variable diameter coiling needle is provided, comprising:

[0007] Needle hub;

[0008] The outer needle assembly includes multiple outward-curled needles, all of which are slidably disposed on the needle base;

[0009] The first opening and closing mechanism is connected to the plurality of said external coiling needles and drives the plurality of said external coiling needles to move closer or further apart from each other;

[0010] An inner needle assembly is disposed between a plurality of outer coiled needles. The inner needle assembly includes two clamping ends, which are slidably disposed close to or away from the needle seat.

[0011] The second opening and closing mechanism is kinetically connected to at least one of the clamping ends to drive the clamping end to slide.

[0012] In some embodiments, the needle holder is provided with a plurality of guide structures arranged radially thereon, and the outwardly coiled needle is slidably disposed on the needle holder through the guide structures.

[0013] In some embodiments, the first opening and closing mechanism includes a rotating sleeve and a plurality of linkage groups connected to the rotating sleeve, the linkage groups including:

[0014] A push rod, which is connected to the outward-winding needle;

[0015] A connecting rod, one end of which is rotatably connected to the rotating sleeve, and the other end of which is connected to the push rod, wherein the rotation axis of the connecting rod is parallel to but not collinear with the rotation axis of the rotating sleeve.

[0016] In some embodiments, the needle holder has multiple guide grooves, and the push rod passes through the guide grooves into the needle holder.

[0017] In some embodiments, the first opening and closing mechanism further includes a self-locking element, which includes a threaded rod that passes through the rotating sleeve and is threadedly connected to the rotating sleeve.

[0018] In some embodiments, the first opening and closing mechanism includes a first opening and closing rod, the front end of which is cone-shaped. The first opening and closing rod passes through the needle seat, and the outer coiled needle is provided with a first follower structure, which is used to contact the first opening and closing rod.

[0019] In some embodiments, the outer needle assembly further includes a plurality of first elastic elements, the two ends of which are respectively connected to the needle seat and the outer coiled needle.

[0020] In some embodiments, the inner needle assembly includes:

[0021] The first inward-curling needle is slidably disposed on the needle seat and is connected to the second opening and closing mechanism in a transmission manner;

[0022] The second inward-curving needle is fixed to the needle seat;

[0023] Multiple second elastic elements, with their two ends connected to the first inward-curling needle and the second inward-curling needle, respectively.

[0024] In some embodiments, the second opening and closing mechanism includes a second opening and closing rod, the front end of which is cone-shaped and passes through the needle seat. The first inward-rolling needle is provided with a second follower structure, which is used to contact the second opening and closing rod.

[0025] The beneficial effects of the technical solution provided in this application include:

[0026] This application provides a dynamic variable diameter winding needle. Before winding, the material strip passes between two clamping ends, and under the action of the second opening and closing mechanism, the two clamping ends close to clamp the material strip. At the same time, the first opening and closing mechanism drives multiple outer winding needles to move away from each other, thereby increasing the diameter of the outer needle group. The material strip is wound on the outer needle group. When the needle is pulled out after winding, the two clamping ends of the inner needle group move away from each other and no longer clamp the material strip. At the same time, the first opening and closing mechanism drives multiple outer winding needles to move closer to each other, thereby reducing the diameter of the outer needle group. This leaves a gap between the battery cell and the outer needle group, which facilitates the outer needle group to be pulled out of the battery cell. Moreover, the pulling process is less likely to cause defects such as core pulling or powder shedding from the battery cell.

[0027] Secondly, a winding device is provided, including the dynamically variable diameter needle as described above.

[0028] Another embodiment of this application provides a winding device. Since the winding device includes the aforementioned dynamic variable diameter winding needle, the beneficial effects of the winding device are the same as those of the aforementioned dynamic variable diameter winding needle, and will not be repeated here. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0030] Figure 1 A schematic diagram of a dynamic variable diameter coiling needle provided in an embodiment of this application;

[0031] Figure 2 A schematic diagram from another perspective of the dynamic variable diameter coiling needle provided in the embodiments of this application;

[0032] Figure 3 An exploded view of the dynamically variable diameter coiled needle provided in the embodiments of this application;

[0033] Figure 4 This is a schematic diagram showing the push rod near the center of the needle seat, provided in an embodiment of this application.

[0034] Figure 5 A schematic diagram showing the push rod being away from the center of the needle seat, as provided in an embodiment of this application;

[0035] Figure 6 This is a longitudinal sectional view of the dynamic variable diameter coil needle provided in the embodiments of this application.

[0036] In the diagram: 1. Needle base; 101. Guide structure; 102. Guide groove; 103. Sliding groove; 2. Outer needle assembly; 201. Outer coiled needle; 3. First opening and closing mechanism; 301. Rotating sleeve; 302. Linkage assembly; 3021. Push rod; 3022. Connecting rod; 303. Self-locking component; 304. Rotational power component; 4. Inner needle assembly; 401. First inner coiled needle; 4011. Second follower structure; 402. Second inner coiled needle; 403. Second elastic component; 5. Second opening and closing mechanism. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] This application provides a dynamic variable diameter needle winding device. The dynamic variable diameter needle winding device uses an inner needle group to clamp the material strip and expands the diameter of the outer needle group before winding, then reduces the diameter of the outer needle group during needle removal. This creates a needle removal gap between the outer needle group and the battery cell, facilitating the removal of the needle from the battery cell. This application solves the technical problem in related technologies where the needle removal process easily causes defects such as battery cell pull-out and powder shedding, affecting the quality of battery cell molding.

[0039] Reference Figure 1 and Figure 2 A dynamic variable diameter coiling needle includes a needle holder 1 and an outer needle assembly 2 and an inner needle assembly 4 disposed on the needle holder 1. The inner needle assembly 4 is used to clamp the material strip, and the material strip is wound on the outer needle assembly 2.

[0040] Reference Figure 1 and Figure 2 Specifically, the needle holder 1 is cylindrical and is used to be mounted on a winding device so that it can be rotated by the winding device. The length direction of the outer coiled needle 201 is consistent with the rotation axis direction of the needle holder 1.

[0041] Reference Figures 1-3 The outer needle assembly 2 includes multiple outward-curled needles 201, all with the same length direction. These needles are slidably mounted on the needle base 1, moving closer to or further away from each other. Preferably, the sliding direction of the outward-curled needles 201 is radially arranged along the needle base 1. When the needles are close together, they slide towards the center of the needle base 1; when they are far apart, they slide towards the edge of the needle base 1. In this embodiment, four outward-curled needles 201 are used.

[0042] Reference Figures 1-3 Furthermore, the needle holder 1 is provided with multiple guide structures 101 arranged radially thereon, and the outward-curled needle 201 is slidably disposed on the needle holder 1 through the guide structures 101. The arrangement of the guide structures 101 makes the sliding of the outward-curled needle 201 more stable. Preferably, the multiple guide structures 101 are evenly distributed circumferentially with the axis of the needle holder 1 as the center line.

[0043] Reference Figures 1-3 Specifically, the guide structure 101 includes a guide rail assembly, and the outer coiled needle 201 is slidably disposed on the needle seat 1 through the guide rail assembly. In other embodiments, the guide structure 101 may also be a groove, and the outer coiled needle 201 is slidably disposed in the groove.

[0044] Reference Figures 1-3 The dynamic variable diameter coiling needle also includes a first opening and closing mechanism 3, in which multiple outer coiling needles 201 are connected by a transmission to drive the outer coiling needles 201 to slide on the needle holder 1.

[0045] Before winding, the first opening and closing mechanism 3 drives multiple outer winding needles 201 to move away from each other, and the diameter of the outer needle group 2 composed of multiple outer winding needles 201 becomes larger. After the material strip is wound and formed on the outer needle group 2, the first opening and closing mechanism 3 drives multiple outer winding needles 201 to slide closer to each other, reducing the diameter of the outer needle group 2, so that a gap is left between the outer needle group 2 and the battery cell, so as to facilitate the removal of the outer needle group 2 from the battery cell. When removing the needle, it is not easy to cause defects such as battery cell pull-out or powder shedding.

[0046] Reference Figures 2-5 Specifically, the first opening and closing mechanism 3 includes a rotating sleeve 301 and multiple connecting rod groups 302 connected to the rotating sleeve 301. The number of connecting rod groups 302 corresponds to the number of externally coiled needles 201. The rotating sleeve 301 is connected to an external rotating drive component, and the rotation axis of the rotating sleeve 301 is aligned with the rotation axis of the needle holder 1. The rotation of the rotating sleeve 301 drives the multiple connecting rod groups 302 to rotate together. Each connecting rod group 302 includes a push rod 3021 and a connecting rod 3022. The push rod 3021 is fixedly connected to the externally coiled needle 201, one end of the connecting rod 3022 is rotatably connected to the rotating sleeve 301, and the other end of the connecting rod 3022 is rotatably connected to the push rod 3021. The rotation axis of the connecting rod 3022 is parallel to but not collinear with the rotation axis of the rotating sleeve 301. (Refer to...) Figure 4 and Figure 5 It is understandable that multiple linkage groups 302 are circumferentially distributed around the axis of the rotating sleeve 301.

[0047] Reference Figure 4 and Figure 5The external rotating drive unit drives the rotating sleeve 301 to rotate, which in turn causes the connecting rod 3022 and the push rod 3021 to swing. Since the sliding direction of the outer coiled needle 201 is restricted by the guide structure 101, the outer coiled needle 201 slides under the push of the push rod 3021. That is, by driving the rotating sleeve 301 to rotate, multiple connecting rod groups 302 can simultaneously drive multiple outer coiled needles 201 to slide.

[0048] Reference Figures 3-5 Furthermore, the needle holder 1 is provided with multiple guide grooves 102, which penetrate the needle holder 1 and are arranged radially along the needle holder 1. The number of guide grooves 102 is the same as the number of outward-curling needles 201. The push rod 3021 passes through the guide groove 102 and passes through the needle holder 1. Furthermore, the push rod 3021 slides within the guide groove 102 so that the guide groove 102 limits the swing direction of the push rod 3021.

[0049] Reference Figure 3 and Figure 6 The first opening and closing mechanism 3 further includes a self-locking component 303, which restricts the rotation of the rotating sleeve 301 to maintain the position of the outer coiled needle 201. Specifically, the self-locking component 303 includes a threaded rod. The inner hole of the rotating sleeve 301 has a threaded structure, and the threaded rod passes through the rotating sleeve 301 and is threadedly connected to it. The rotation axis of the threaded rod is aligned with that of the rotating sleeve 301. An external rotation drive is driven to rotate the rotating sleeve 301. When the rotating sleeve 301 rotates, it rotates on the threaded rod, and the self-locking of the rotating sleeve 301 is achieved through the threaded engagement between the rotating sleeve 301 and the threaded rod.

[0050] It should be noted that the push rod 3021 passes through the connecting rod 3022 to be rotatably connected to the connecting rod 3022. When the rotating sleeve 301 rotates on the threaded rod, the rotating sleeve 301 moves axially relative to the threaded rod. At this time, the connecting rod 3022 and the push rod 3021 move relative to each other to prevent the connecting rod 3022 from driving the push rod 3021 to push or pull the outer coiled needle 201, thereby supporting the axial movement of the rotating sleeve 301.

[0051] Preferably, the thread on the threaded rod is a trapezoidal thread, which ensures that the rotating sleeve 301 and the threaded rod have good self-locking performance while allowing the rotating sleeve to rotate on the threaded rod.

[0052] Reference Figures 1-3In this embodiment, the dynamic variable diameter needle coil also includes a rotating power component 304, which is drivenly connected to the rotating sleeve 301 to drive the rotating sleeve 301 to rotate. Specifically, the driving end of the rotating power component 304 is connected to the rotating sleeve 301. The rotating power component 304 includes a DD motor. In this embodiment, the rotating power component 304 and the rotating sleeve 301 are integrated together, improving the overall integrity of the dynamic variable diameter needle coil.

[0053] In some embodiments, the first opening and closing mechanism 3 includes a first opening and closing rod connected to an external linear module, which drives the first opening and closing rod to move along its axial direction. The front end of the first opening and closing rod is tapered and passes through the needle holder 1. Multiple outward-curling needles 201 are provided with a first follower structure, and the front end of the first opening and closing rod contacts the first follower structure. By driving the first opening and closing rod to move along its axial direction, the first opening and closing rod pushes against the first follower structure, thereby causing the outward-curling needles 201 to slide, thus separating the multiple outward-curling needles 201. The first follower structure includes a follower wheel, which is rotatably connected to the outward-curling needles 201.

[0054] Furthermore, in this embodiment, the first opening and closing mechanism 3 also includes a plurality of first elastic elements, the number of which is the same as the number of outward-curling needles 201, and the two ends of the first elastic elements are respectively connected to the outward-curling needles 201 and the needle seat 1. When the first opening and closing rod pushes the first follower structure to separate the plurality of outward-curling needles 201, the first elastic element deforms; when the first opening and closing rod is not in contact with the first follower structure, the elastic force of the first elastic element drives the outward-curling needles 201 to slide, so that the plurality of outward-curling needles 201 move closer together. The first elastic element includes a spring.

[0055] Reference Figures 1-3 The inner needle assembly 4 is located among multiple outer coiled needles 201 and includes two clamping ends that move closer or further apart. At least one clamping end is slidably disposed on the needle holder 1. In this embodiment, one clamping end is slidably disposed on the needle holder 1, and the other clamping end is fixed to the needle holder 1. The strip passes between the two clamping ends and is clamped by the two clamping ends.

[0056] Reference Figure 3 and Figure 6 In this embodiment, the inner needle assembly 4 includes a first inward-curling needle 401 and a second inward-curling needle 402, which are two clamping ends. The first inward-curling needle 401 is slidably disposed on the needle base 1, and the sliding direction of the first inward-curling needle 401 is arranged radially along the needle base 1. The second inward-curling needle 402 is fixed to the needle base 1 by bolts. By driving the first inward-curling needle 401 to slide toward the second inward-curling needle 402, the material strip located between the first inward-curling needle 401 and the second inward-curling needle 402 is clamped.

[0057] Reference Figure 3and Figure 6 The needle holder 1 has a sliding groove 103, which is arranged radially along the length of the needle holder 1. The first inward-curling needle 401 is slidably disposed in the sliding groove 103 via a guide rail assembly, and the second inward-curling needle 402 is fixed in the sliding groove 103.

[0058] Reference Figure 3 and Figure 6 Furthermore, the inner needle assembly 4 also includes multiple second elastic elements 403. The two ends of each second elastic element 403 are fixedly connected to the first inner winding needle 401 and the second inner winding needle 402, respectively. In this embodiment, when the first inner winding needle 401 and the second inner winding needle 402 approach each other, the second elastic element 403 deforms. During winding, it causes the first inner winding needle 401 to move closer to the second inner winding needle 402 and clamp the material strip. After winding is completed, the elastic force of the second elastic element 403 will cause the first inner winding needle 401 to slide away from the second inner winding needle 402. The second elastic element 403 is designed to leave a gap between the first inner winding needle 401 and the second inner winding needle 402, facilitating the material strip to pass between them. In this embodiment, the second elastic element 403 includes a spring.

[0059] Reference Figure 3 and Figure 6 The dynamic variable diameter winding needle also includes a second opening and closing mechanism 5. The second opening and closing mechanism 5 has at least one clamping end connected to the transmission. In this embodiment, the second opening and closing mechanism 5 is connected to the first inner winding needle 401 to drive the first inner winding needle 401 to approach and press against the second inner winding needle 402, so as to clamp the material strip between the first inner winding needle 401 and the second inner winding needle 402.

[0060] Reference Figure 3 and Figure 6 Specifically, the second opening and closing mechanism 5 includes a second opening and closing rod, which is connected to an external linear module, and the external linear module drives the second opening and closing rod to move along its axial direction. The front end of the second opening and closing rod is tapered and passes through the needle seat 1. In this embodiment, the second opening and closing rod passes through a threaded rod. The first inward-curling needle 401 is provided with a first follower structure, and the front end of the first opening and closing rod contacts the first follower structure. By driving the second opening and closing rod to move along its axial direction, the second opening and closing rod pushes the second follower structure 4011, which in turn drives the first inward-curling needle 401 to slide, thereby driving the first inward-curling needle 401 to slide closer to the second inward-curling needle 402. The second follower structure 4011 includes a follower wheel, which is rotatably connected to the outward-curling needle 201.

[0061] The working process of this dynamic variable diameter coiling needle is as follows:

[0062] Before winding, the first opening and closing mechanism 3 drives multiple outer winding needles 201 to move away from each other, thereby increasing the diameter of the outer needle group 2. The material strip extends between the multiple outer winding needles 201 and passes between the first inner winding needle 401 and the second inner winding needle 402. The second opening and closing mechanism 5 drives the first inner winding needle 401 to slide close to the second inner winding needle 402, clamping the material strip between the first inner winding needle 401 and the second inner winding needle 402.

[0063] After winding is completed, the second opening and closing mechanism 5 retracts, the first inner winding needle 401 moves away from the second inner winding needle 402 to loosen the material strip, and at the same time the first opening and closing mechanism 3 drives multiple outer winding needles 201 to move closer to each other to reduce the diameter of the outer needle group 2, so that a gap is left between the outer needle group 2 and the battery cell, so as to facilitate the outer needle group 2 being pulled out of the battery cell.

[0064] This application provides a dynamic variable diameter winding needle. Before winding, the material strip passes between two clamping ends, and under the action of the second opening and closing mechanism 5, the two clamping ends close to clamp the material strip. At the same time, the first opening and closing mechanism 3 drives multiple outer winding needles 201 to move away from each other, thereby increasing the diameter of the outer needle group 2. The material strip is wound on the outer needle group 2. When the needle is pulled out after winding, the two clamping ends of the inner needle group 4 move away from each other and no longer clamp the material strip. At the same time, the first opening and closing mechanism 3 drives multiple outer winding needles 201 to move closer to each other, thereby reducing the diameter of the outer needle group 2. This leaves a gap between the battery cell and the outer needle group 2, which facilitates the outer needle group 2 to be pulled out of the battery cell. Moreover, the pulling process is less likely to cause defects such as core pulling or powder shedding from the battery cell.

[0065] Another embodiment of this application provides a winding device including a dynamically variable diameter needle as described above.

[0066] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0067] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0068] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A dynamic variable diameter coiling needle, characterized in that, It includes: Needle hub; The outer needle assembly includes multiple outward-curled needles, all of which are slidably disposed on the needle base; The first opening and closing mechanism is connected to the plurality of said external coiling needles and drives the plurality of said external coiling needles to move closer or further apart from each other; An inner needle assembly is disposed between a plurality of outer coiled needles. The inner needle assembly includes two clamping ends, which are slidably disposed close to or away from the needle seat. A second opening and closing mechanism is kinetically connected to at least one of the clamping ends to drive the clamping ends to slide. The first opening and closing mechanism includes a rotating sleeve and a plurality of linkages connected to the rotating sleeve, the linkages including: A push rod, which is connected to the outward-winding needle; A connecting rod, one end of which is rotatably connected to the rotating sleeve, and the other end of which is connected to the push rod, wherein the rotation axis of the connecting rod is parallel to but not collinear with the rotation axis of the rotating sleeve.

2. The dynamic variable diameter coiling needle according to claim 1, characterized in that, The needle holder is provided with multiple guide structures arranged radially thereon, and the outward-curled needle is slidably disposed on the needle holder through the guide structures.

3. The dynamic variable diameter coiling needle according to claim 2, characterized in that, The needle holder has multiple guide grooves, and the push rod passes through the guide grooves into the needle holder.

4. The dynamic variable diameter coiling needle according to claim 2, characterized in that, The first opening and closing mechanism further includes a self-locking component, which includes a threaded rod that passes through the rotating sleeve and is threadedly connected to the rotating sleeve.

5. The dynamic variable diameter coiling needle according to claim 1 or 2, characterized in that, The first opening and closing mechanism includes a first opening and closing rod, the front end of which is cone-shaped. The first opening and closing rod passes through the needle seat. The outer coiled needle is provided with a first follower structure, and the first follower structure is used to contact the first opening and closing rod.

6. The dynamic variable diameter coiling needle according to claim 5, characterized in that, The outer needle assembly also includes a plurality of first elastic elements, the two ends of which are connected to the needle base and the outer coiled needle, respectively.

7. The dynamic variable diameter coiling needle according to claim 1, characterized in that, The inner needle assembly includes: The first inward-curling needle is slidably disposed on the needle seat and is connected to the second opening and closing mechanism in a transmission manner; The second inward-curving needle is fixed to the needle seat; Multiple second elastic elements, with their two ends connected to the first inward-curling needle and the second inward-curling needle, respectively.

8. The dynamic variable diameter coiling needle according to claim 7, characterized in that, The second opening and closing mechanism includes a second opening and closing rod, the front end of which is cone-shaped. The second opening and closing rod passes through the needle seat. The first inward-rolling needle is provided with a second follower structure, which is used to contact the second opening and closing rod.

9. A winding device, characterized in that, Includes the dynamic variable diameter needle as described in any one of claims 1 to 8.

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