A method for manufacturing a polypropylene insulated core

Abstract

This invention relates to the field of polypropylene insulated wire cores, specifically a method for manufacturing polypropylene insulated wire cores. This method improves the internal stress of polypropylene insulated wire cores. Furthermore, this invention optimizes the temperature gradient design to provide a good cooling environment for the polypropylene insulated wire core, thus improving its internal stress. Based on the thin-shell theory of elasticity, a winding reel with an appropriate diameter is selected, which not only reduces the internal stress of the polypropylene insulated wire core but also avoids excessively large reel diameters, preventing material waste during reel production. Moreover, the optimized design of the winding reel gives it the ability to flexibly adjust its diameter, making it suitable for winding insulated wire cores of different diameters, thus enhancing its adaptability.

Description

Technical Field

[0001] This invention relates to the field of polypropylene insulated wire cores, specifically a method for manufacturing polypropylene insulated wire cores. Background Technology

[0002] Modified polypropylene is a thermoplastic insulating material. During the extrusion process of polypropylene insulated wires with rated voltages of 6kV to 35kV, the polypropylene insulating material will undergo orientation crystallization due to high temperature stretching. The molecular chain segments are forcibly straightened from a disordered entangled state. During the subsequent rapid cooling process, the molecular chain segments "freeze", resulting in large internal stress inside the insulation.

[0003] Meanwhile, when the insulated wire core is wound onto the coil, due to the different bending radii on the inner and outer sides of the insulated wire core, the inner side is subjected to compressive stress and the outer side is subjected to tensile stress. The electric field intensity in these stress concentration areas will increase significantly, which can easily trigger partial discharge and damage the insulation layer. The generation of internal insulation stress will significantly reduce the insulation performance of the insulated wire core.

[0004] In the actual production process of insulated wire cores, insulated wire cores of different diameters are processed according to production specifications. When winding insulated wire cores of different diameters onto a spool, a winding spool that matches the diameter of the insulated wire core is required. When the diameter of the insulated wire core increases, the diameter of the winding spool must also increase accordingly. However, the current winding spools have a single diameter design, which cannot adapt to the winding of insulated wire cores of various diameters.

[0005] Therefore, a method for manufacturing polypropylene insulated wire cores is proposed to address the above problems. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by this invention to solve its technical problem is: a method for manufacturing polypropylene insulated wire cores, comprising the following steps:

[0008] S1: Molten material, which is the insulating raw material that is heated and melted, and then wrapped around the outer surface of the conductor by an extruder;

[0009] S2: Temperature gradient design:

[0010] The maximum temperature of the extruder is limited to 195℃. This temperature range can ensure the melt flowability of the insulating raw material and avoid thermal degradation.

[0011] A six-segment gradient cooling system using cross-linked pipes is adopted, with the temperature of each segment controlled at 160℃→140℃→120℃→100℃→80℃→60℃, and each pipe segment is 3-5m long. The temperature is controlled and cooled by a combination of air cooling and water cooling.

[0012] Extrusion line speed matching: The production line speed is controlled at 6-8m / min to ensure that the cooling rate of the insulation layer is ≤1.5℃ / s, and to avoid the stress of molecular chain freezing caused by sudden cooling;

[0013] Aging treatment mechanism: A constant temperature aging zone (60℃±2℃) is set in the end cooling section and maintained for 30 to 45 minutes. By utilizing the molecular chain segment movement characteristics above the glass transition temperature of polypropylene (Tg≈-10℃), the reconstruction of the crystallization zone is promoted, residual stress is released, and the volume shrinkage rate of the insulation layer is reduced to below 0.3%.

[0014] S3: Rewinding. The inner radius of the reel must meet the following requirement: R≥15D+ΔR, where D is the equivalent outer diameter of the insulated wire core and ΔR is the safety margin (≥5mm).

[0015] The winding reel shown in S3 includes a rotating shaft, on which are symmetrically arranged adjustment components for adjusting the radius of the inner cylinder of the winding reel. Each adjustment component includes two hydraulic rods symmetrically fixed to the rotating shaft. The output end of each hydraulic rod points to the end of the rotating shaft, and the output ends of two adjacent hydraulic rods are fixed to a ring. The ring is sleeved on the rotating shaft and can move along the axis of the rotating shaft.

[0016] Multiple push rods are rotatably connected to the outer ring of each ring body, and each push rod has an arc-shaped plate at its end. The arc-shaped plates are arranged in a circumferential array around the rotating shaft.

[0017] The end of the arc-shaped plate is provided with a disc-shaped side plate, which is coaxially fixed to the rotating shaft.

[0018] Preferably, each of the arc-shaped plates has a guide rod fixed to its end, and the axis of the guide rod is arranged parallel to the axis of rotation.

[0019] Multiple strip-shaped guide holes are provided on each side plate, and the guide holes are arranged radially on the side plate, with guide rods slidably connected to the guide rods.

[0020] Preferably, multiple support plates are fixedly connected to the outer ring of the middle of the rotating shaft in a circumferential array, and two electric actuators are symmetrically fixedly connected to the end of each support plate, and an insert plate is fixedly connected to the output end of each electric actuator.

[0021] Each of the top rods has multiple locking blocks on its side wall, and the insert plate can be inserted into the gap between two adjacent locking blocks.

[0022] Preferably, each of the insert plates is U-shaped and is inserted into the gap between two adjacent blocks, with the two sides of the insert plate clamped to the two sides of the top rod.

[0023] Preferably, the rotating shaft has a through hole inside, a mandrel is provided in the through hole, and multiple sets of protrusions are symmetrically provided on the mandrel, with two protrusions in each set symmetrically located on the outer surface of the mandrel.

[0024] Multiple sets of telescopic holes are provided on the rotating shaft. Each set of telescopic holes extends into the through hole. The two telescopic holes in each set are opposite each other. A limiting block is provided in the telescopic hole. One end of the limiting block protrudes out of the telescopic hole, and the other end of the limiting block is fixedly connected to a spring. The end of the spring is fixedly connected to a pressing block. The pressing block is arranged opposite to the protrusion on the spindle. Both the pressing block and the protrusion are made of magnetic material, and the protrusion can attract the pressing block.

[0025] Preferably, a torsion spring is sleeved at the middle position of the mandrel, with one end of the torsion spring fixed to the inner wall of the through hole and the other end of the torsion spring fixed to the mandrel.

[0026] Preferably, a notch is provided at one corner of the end of the arc-shaped plate, and a notch is also provided on the side of the arc-shaped plate. The notch and the notch are located on the same side of the end of the arc-shaped plate. A set screw is provided in the notch. The set screw thread passes through the arc-shaped plate and extends into the notch. The end of the set screw is rotatably connected to a top plate.

[0027] Preferably, each of the two side plates has a strip hole, the strip holes on the two side plates are arranged opposite to each other, and a pressing rod is provided in the strip hole. The end of the pressing rod extends to the outside of the side plate, and the end of the pressing rod is fastened to the side plate by a nut.

[0028] Multiple locking blocks are slidably connected to the extrusion rod. The surface of the locking blocks has an arc-shaped groove, which is used to press against the surface of the cable.

[0029] Preferably, the rotating shaft is symmetrically provided with support components, which are located near the end of the arc plate. The support components include multiple sleeves perpendicular to the axis of the rotating shaft. The sleeves are fixed to the rotating shaft, and a rod is sleeved inside the sleeve. The end of the rod is fixed to the arc plate.

[0030] Preferably, each cross-linked pipe section adopts a double-layer spiral flow guiding structure pipe, the inner layer of each cross-linked pipe section is provided with a ceramic wear-resistant coating, and the outer layer of each cross-linked pipe section is equipped with a PID intelligent temperature control module.

[0031] The advantages of this invention are:

[0032] 1. In this invention, the manufacturing method for polypropylene insulated wire cores optimizes the temperature gradient design, providing a good cooling environment for the polypropylene insulated wire cores and improving the internal stress of the polypropylene insulated wire cores. Furthermore, based on the thin-shell theory of elasticity, a winding reel with an appropriate diameter is selected. This not only reduces the internal stress of the polypropylene insulated wire cores but also prevents the winding reel from being too large, thus avoiding waste of production materials. Moreover, the optimized design of the winding reel gives the traditional winding reel the function of flexibly adjusting its diameter, making it suitable for winding insulated wire cores of different diameters, thus enhancing its adaptability.

[0033] 2. In this invention, the output end of the designed electric actuator drives the insert plate to move towards the top rod. The insert plate is inserted between two adjacent locking blocks and presses against the top rod, supporting and holding the top rod in place, thereby stabilizing the arc-shaped plate, further improving the stability of the arc-shaped plate, and enabling the winding of insulated wire cores with larger diameters. Attached Figure Description

[0034] Figure 1 This is a flowchart of the polypropylene insulated wire core manufacturing method in this invention;

[0035] Figure 2 This is a perspective view of the winding reel in this invention;

[0036] Figure 3 This is a schematic diagram of the internal structure of the take-up reel in this invention;

[0037] Figure 4 This is a three-dimensional view of multiple curved plates used in this invention.

[0038] Figure 5 This is the front view of the adjustment component in this invention;

[0039] Figure 6 This is a perspective view of the adjustment component in this invention;

[0040] Figure 7 This is a perspective view of the cooperation between the side plate and the arc plate in this invention;

[0041] Figure 8 This is a perspective view of the side plate in this invention;

[0042] Figure 9 This is a perspective view of the arc-shaped plate in this invention;

[0043] Figure 10 This is a perspective view of the fit between the insulated wire core and the arc-shaped plate in this invention;

[0044] Figure 11 This is a perspective view of the fit between the insert plate and the push rod in this invention;

[0045] Figure 12 This is a perspective view of the mandrel in this invention;

[0046] Figure 13 This is a side view of the mandrel in this invention;

[0047] Figure 14 This is a cross-sectional view of the mandrel in this invention;

[0048] Figure 15 This is a schematic diagram of the fit between the limiting block and the mandrel in this invention.

[0049] In the diagram: 101. Insulated wire core; 1. Winding reel; 2. Shaft; 3. Hydraulic rod; 4. Top rod; 5. Arc plate; 6. Side plate; 7. Guide rod; 8. Guide hole; 9. Support plate; 10. Electric actuator; 11. Insert plate; 12. Locking block; 13. Through hole; 14. Core shaft; 15. Protrusion; 16. Telescopic hole; 17. Limiting block; 18. Spring; 19. Extrusion block; 20. Torsion spring; 21. Notch; 22. Recess; 23. Top screw; 24. Top plate; 25. Strip hole; 26. Extrusion rod; 27. Locking block; 28. Sleeve; 29. ​​Rod body. Detailed Implementation

[0050] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0051] Reference Figure 1 - Figure 9 A method for manufacturing a polypropylene insulated wire core, used to improve the internal stress of the polypropylene insulated wire core 101, and the method for manufacturing the polypropylene insulated wire core includes the following steps:

[0052] S1: Molten material, which is the insulating raw material that is heated and melted, and then wrapped around the outer surface of the conductor by an extruder;

[0053] S2: Temperature gradient design:

[0054] The maximum temperature of the extruder is limited to 195℃. This temperature range can ensure the melt flowability of the insulating raw material and avoid thermal degradation.

[0055] A six-segment gradient cooling system using cross-linked pipes is adopted, with the temperature of each segment controlled at 160℃→140℃→120℃→100℃→80℃→60℃, and each pipe segment is 3-5m long. The temperature is controlled and cooled by a combination of air cooling and water cooling.

[0056] Extrusion line speed matching: with a cross-section of 300mm 2 Taking insulated core 101 as an example, the production speed is controlled at 6-8m / min to ensure that the cooling rate of the insulation layer is ≤1.5℃ / s, and to avoid the stress of molecular chain freezing caused by sudden cooling.

[0057] Aging treatment mechanism: A constant temperature aging zone (60℃±2℃) is set in the end cooling section and maintained for 30 to 45 minutes. By utilizing the molecular chain segment movement characteristics of polypropylene with a glass transition temperature Tg≈-10℃ or higher, the reconstruction of the crystallization zone is promoted, residual stress is released, and the volume shrinkage rate of the insulation layer is reduced to below 0.3%.

[0058] S3: Winding. According to the thin-shell theory of elasticity, the inner radius of the winding reel 1 must meet the following requirement: R≥15D+ΔR, where D is the equivalent outer diameter of the insulated core 101, and ΔR is the safety margin ≥5mm.

[0059] The winding reel 1 shown in S3 includes a rotating shaft 2. The rotating shaft 2 is symmetrically provided with adjusting components for adjusting the inner radius of the winding reel 1. Each adjusting component includes two hydraulic rods 3 symmetrically fixed to the rotating shaft 2. The output end of each hydraulic rod 3 points to the end of the rotating shaft 2, and the output ends of two adjacent hydraulic rods 3 are fixedly connected to a ring 30. The ring 30 is sleeved on the rotating shaft 2 and can move along the axis of the rotating shaft 2.

[0060] Multiple push rods 4 are rotatably connected to the outer ring of each ring body 30. Each push rod 4 has an arc-shaped plate 5 at its end. The arc-shaped plates 5 are arranged in a circular array around the rotating shaft 2.

[0061] The end of the arc plate 5 is provided with a disc-shaped side plate 6, and the side plate 6 is fixedly connected to the rotating shaft 2 along the same axis.

[0062] The winding reel 1 is designed to flexibly adjust the winding diameter, making it suitable for winding polypropylene insulated wire cores 101 of different diameters. Specifically, the hydraulic rod 3 is driven by hydraulic oil. An oil pipe can be installed on the side plate 6, and the oil pipe is connected to the hydraulic rod 3.

[0063] Two adjacent hydraulic rods 3 simultaneously push the ring 30, as shown in the figure. The ring 30 moves towards the end of the rotating shaft 2. At the same time, the ring 30 pushes the top rod 4, and the top rod 4 pushes the arc plate 5. At this time, the diameter of the circle formed by the multiple arc plates 5 gradually increases, which is suitable for winding up polypropylene insulated wire core 101 with a larger diameter.

[0064] The manufacturing method of this polypropylene insulated wire core 101 optimizes the temperature gradient design, providing a good cooling environment for the polypropylene insulated wire core 101 and improving the internal stress of the polypropylene insulated wire core 101. In addition, based on the thin shell theory of elasticity, a winding reel 1 with an appropriate diameter is selected, which not only reduces the internal stress of the polypropylene insulated wire core 101, but also avoids the waste of production materials caused by the excessively large diameter of the winding reel 1. Furthermore, the optimized design of the winding reel 1 gives the traditional winding reel 1 the function of flexibly adjusting its diameter, which can be used to wind insulated wire cores 101 with different diameters, making it more adaptable.

[0065] Reference Figure 8 - Figure 10 Each of the arc-shaped plates 5 has a guide rod 7 fixedly connected to its end, and the axis of the guide rod 7 is arranged parallel to the axis of the rotating shaft 2;

[0066] Multiple strip-shaped guide holes 8 are provided on each side plate 6. The guide holes 8 are arranged radially on the side plate 6, and the guide rod 7 is slidably connected to the guide rod 7.

[0067] In order to improve the overall performance of the winding reel 1, that is, to improve its stability and enable it to wind up polypropylene insulated wire cores 101 with a larger diameter, the arc plate 5 and the side plate 6 are movably connected together.

[0068] The side plate 6 is fixed to the rotating shaft 2. The guide hole 8 on the side plate 6 is used to connect the guide rod 7. The guide rod 7 can slide along the guide bar and move with the arc plate 5 expanding outward to the rotating shaft 2, thus restricting the movement dimension of the arc plate 5. This ensures that the arc plate 5 can only move along the length direction of the guide hole 8, thus constraining the arc plate 5 and preventing it from becoming skewed, which would affect the roundness of the winding reel 1. If the roundness of the winding reel 1 is damaged, that is, if the arc plate 5 becomes skewed, the insulated wire core 101 will be easily subjected to local compression by the arc plate 5 during winding, especially at the skewed part of the arc plate 5, which would damage the outer surface of the insulated wire core 101.

[0069] Reference Figure 3 - Figure 6 The rotating shaft 2 has multiple support plates 9 fixedly connected in a circular array on the outer ring in the middle. Two electric actuators 10 are symmetrically fixedly connected to the end of each support plate 9. Each electric actuator 10 has an insertion plate 11 fixedly connected to its output end.

[0070] Each of the top rods 4 has multiple locking blocks 12 on its side wall, and the insert plate 11 can be inserted into the gap between two adjacent locking blocks 12;

[0071] The support plate 9 is used to mount the electric actuator 10 on the rotating shaft 2. The wires of the electric actuator 10 extend to the side plate 6 and are connected to an external power source, which can drive the electric actuator 10 to perform its function.

[0072] The hydraulic pipe connecting the hydraulic rod 3 extends to the side plate 6, and a valve is installed at the end of the hydraulic pipe to lock the oil pressure inside the hydraulic rod 3. After adjusting the outward expansion movement of the arc plate 5, the hydraulic pipe is removed, the valve is closed, and then the electric push rod 10 is driven. The output end of the electric push rod 10 drives the insert plate 11 to move towards the top rod 4. The insert plate 11 is inserted between two adjacent locking blocks 12 and presses against the top rod 4 to support and hold the top rod 4, thereby supporting and stabilizing the arc plate 5, further improving the stability of the arc plate 5, and enabling the winding of the insulated wire core 101 with a larger diameter.

[0073] Reference Figure 5 and Figure 11Each of the insert plates 11 is U-shaped and is inserted into the gap between two adjacent locking blocks 12. The insert plates 11 are clamped on both sides of the top rod 4.

[0074] The insert plate 11 rests against the push rod 4, and at the same time, the insert plate 11 is constrained between two adjacent locking blocks 12, and the two sides of the insert plate 11 are partially wrapped around the two sides of the push rod 4, further constraining the push rod 4 and the insert plate 11, so as to prevent the insert plate 11 from resting against the push rod 4, or the insert plate 11 from sliding away from the push rod 4, causing the electric push rod 10 to lose its squeezing support on the push rod 4.

[0075] Reference Figure 5 and Figure 6 ,as well as Figure 12 - Figure 15 The rotating shaft 2 has a through hole 13 inside, and a spindle 14 is provided inside the through hole 13. Multiple sets of protrusions 15 are symmetrically provided on the spindle 14, and two protrusions 15 in each set are symmetrically arranged on the outer surface of the spindle 14.

[0076] Multiple sets of telescopic holes 16 are provided on the rotating shaft 2. Each set of telescopic holes 16 extends into the through hole 13. The two telescopic holes 16 in each set are opposite to each other. A limiting block 17 is provided in the telescopic hole 16. One end of the limiting block 17 protrudes out of the telescopic hole 16, and the other end of the limiting block 17 is fixedly connected to a spring 18. The end of the spring 18 is fixedly connected to a pressing block 19. The pressing block 19 is arranged opposite to the protrusion 15 on the spindle 14. Both the pressing block 19 and the protrusion 15 are made of magnetic material, and the protrusion 15 can attract the pressing block 19.

[0077] When it is necessary to increase the diameter of the take-up reel 1, the hydraulic rod 3 is directly driven. The hydraulic rod 3 pushes the ring 30 to move along the rotating shaft 2. At this time, the ring 30 will squeeze the inclined surface of the limiting block 17 and pass over the limiting block 17. After the diameter adjustment of the take-up reel 1 is completed, the inner side of the ring 30 presses against the limiting block 17, and the ring 30 is restricted and stabilized. The hydraulic rod 3 assists in squeezing and constraining the ring 30. When the hydraulic rod 3 is accidentally depressurized, the limiting block 17 can then restrict the ring 30, thus constraining the arc plate 5. Both ends of the spindle 14 are equipped with six The prism and mandrel 14 are rotatably connected in the through hole 13. By using a hexagonal socket wrench placed at the end of the mandrel 14, the mandrel 14 is rotated in the through hole 13. The multiple sets of protrusions 15 on the mandrel 14 will move away from the telescopic hole 16. At this time, the protrusions 15 no longer squeeze the extrusion block 19. The protrusions 15 attract the extrusion block 19 to move towards the through hole 13. The limiting block 17 retracts into the telescopic hole 16. The limiting block 17 no longer protrudes from the surface of the rotating shaft 2. At this time, the driving hydraulic rod 3 pulls the ring 30 to move towards the middle of the rotating shaft 2. The ring 30 can then easily move along the axis of the rotating shaft 2.

[0078] Reference Figure 12 and Figure 14A torsion spring 20 is sleeved in the middle of the spindle 14. One end of the torsion spring 20 is fixed to the inner wall of the through hole 13, and the other end of the torsion spring 20 is fixed to the spindle 14.

[0079] A torsion spring 20 is installed on the spindle 14. The torque of the torsion spring 20 torsion the spindle 14, so that the protrusion 15 on the spindle 14 is always opposite to the telescopic hole 16. That is, the protrusion 15 on the spindle 14 always pushes outward against the limiting block 17, so that the limiting block 17 always protrudes from the outer surface of the rotating shaft 2. Only when the spindle 14 is rotated with a hexagonal socket wrench and the torsional force of the hexagonal socket wrench is maintained can the limiting block 17 be retracted into the telescopic hole 16. This design allows the limiting block 17 to protrude from the outer surface of the rotating shaft 2 without external interference and can stably limit the position of the ring 30. It is also a measure to ensure the stability of the ring 30.

[0080] Reference Figure 7 , Figure 9 and Figure 10 The arc plate 5 has a notch 21 at one corner of its end and a notch 22 on its side. The notch 22 and the notch 21 are located on the same side of the end of the arc plate 5. A set screw 23 is provided in the notch 22. The set screw 23 is threaded through the arc plate 5 and extends into the notch 21. The end of the set screw 23 is rotatably connected to a top plate 24.

[0081] Considering that the insulated wire core 101 needs to be fixed on the winding reel 1 during the initial winding stage in order to effectively pull and wind the insulated wire core 101, a structure for fixing the insulated wire core 101 is set on one of the arc-shaped plates 5. The end of the insulated wire core 101 is inserted into the notch 21, and then the set screw 23 is rotated. The set screw 23 pushes the top plate 24 and presses the insulated wire core 101 onto the side plate 6. This structural design can firstly achieve stable compression of the end of the insulated wire core 101, and at the same time, it can compress and fix insulated wire cores 101 of different diameters. Furthermore, only a small section of the end of the insulated wire core 101 needs to be compressed and fixed. When the insulated wire core 101 is put into use later, it will not affect the use of this section of the insulated wire core 101, thus avoiding waste.

[0082] Reference Figure 2 , Figure 3 , Figure 7 and Figure 8 ,as well as Figure 12 - Figure 15 Each of the two side plates 6 has a strip hole 25, the strip holes 25 on the two side plates 6 are arranged opposite to each other, and a pressing rod 26 is provided in the strip hole 25. The end of the pressing rod 26 extends to the outside of the side plate 6, and the end of the pressing rod 26 is fastened to the side plate 6 by a nut.

[0083] Multiple locking blocks 27 are slidably connected to the extrusion rod 26. The surface of the locking block 27 is provided with an arc-shaped groove, which is used to extrude onto the surface of the cable.

[0084] After the winding reel 1 finishes winding the insulated wire core 101, the end of the insulated wire core 101 is in a free state and needs to be temporarily fixed to prevent the entire roll of insulated wire core 101 from loosening. In this embodiment, a pressing rod 26 and a locking block 27 are provided on the side plate 6 to press and lock the end of the insulated wire core 101. Specifically, the pressing rod 26 is inserted through the strip hole 25 on the two side plates 6, and the locking block 27 is pressed on the end of the insulated wire core 101. The multiple locking blocks 27 can press the locking blocks 27 separately onto the surface of the insulated wire core 101, specifically onto the coil wound at the end of the insulated wire core 101. Then, the pressing rod 26 is locked onto the outer wall of the side plate 6 by a nut to stabilize the pressing rod 26, so that the locking block 27 can be stably pressed onto the end of the insulated wire core 101. The operation is simple and the position of the pressing rod 26 can be flexibly adjusted according to the diameter of the coil wound on the insulated wire core 101.

[0085] Reference Figure 3 and Figure 4 The rotating shaft 2 is symmetrically provided with support components. The support components are located near the end of the arc plate 5. The support components include multiple sleeves 28 perpendicular to the axis of the rotating shaft 2. The sleeves 28 are fixed to the rotating shaft 2. A rod 29 is sleeved inside the sleeve 28. The end of the rod 29 is fixed to the arc plate 5.

[0086] The support assembly is designed to limit the offset of the arc plate 5. One end of the rod 29 is fixed to the back of the end of the arc plate 5, and the other end of the rod 29 is slidably connected inside the sleeve 28. The sleeve 28 is vertically fixed to the rotating shaft 2, which restricts the rod 29 to move only in the radial direction of the rotating shaft 2. This further constrains the offset of the arc plate 5, that is, the arc plate 5 can only move in the radial direction of the rotating shaft 2, thereby improving the stability of the circle formed by multiple arc plates 5.

[0087] Each cross-linked pipe section adopts a double-layer spiral flow guiding structure pipe, with a ceramic wear-resistant coating on the inner layer of each cross-linked pipe section and a PID intelligent temperature control module on the outer layer of each cross-linked pipe section.

[0088] The system employs a double-layer spiral flow-guiding pipe structure, with an inner layer featuring a ceramic wear-resistant coating and an outer layer equipped with a PID intelligent temperature control module, achieving a temperature fluctuation accuracy of ±1℃. Optimized cooling medium flow rate ensures uniform heat dissipation under laminar flow conditions, improving cooling stability.

[0089] Working principle:

[0090] The design incorporates a temperature gradient, limiting the extruder's maximum temperature to 195℃. This temperature range ensures the melt flowability of the insulating raw material while preventing thermal degradation. A six-segment gradient cooling system using cross-linking pipes is employed, with each segment controlled at 160℃→140℃→120℃→100℃→80℃→60℃, and each pipe segment being 3-5m long. Temperature control is achieved through a combination of air cooling and water cooling. Extrusion line speed matching: Taking a 20mm diameter insulating core 101 as an example, the production line speed is controlled at 6-8m / min to ensure the insulation layer cooling rate is ≤1.5℃ / s, preventing sudden cooling that could lead to molecular chain freezing stress. A aging treatment mechanism: A constant-temperature aging zone (60℃±2℃) is set in the final cooling section and maintained for 30-45 minutes. Utilizing the molecular chain segment movement characteristics of polypropylene with a glass transition temperature (Tg) of ≈-10℃ or higher, this promotes the reconstruction of the crystallization zone, releases residual stress, and reduces the insulation layer volume shrinkage rate to below 0.3%.

[0091] Meanwhile, a winding reel 1 with a variable winding diameter is designed, which can be used to wind polypropylene insulated wire cores 101 of different diameters. Specifically, the hydraulic rod 3 is driven by hydraulic oil. An oil pipe can be set on the side plate 6, and the oil pipe is connected to the hydraulic rod 3.

[0092] Two adjacent hydraulic rods 3 simultaneously push the ring 30, as shown in the figure. The ring 30 moves towards the end of the rotating shaft 2. At the same time, the ring 30 pushes the top rod 4, and the top rod 4 pushes the arc plate 5. At this time, the diameter of the circle formed by the multiple arc plates 5 gradually increases, which is suitable for winding up polypropylene insulated wire core 101 with a larger diameter.

[0093] The manufacturing method of this polypropylene insulated wire core 101 optimizes the temperature gradient design, providing a good cooling environment for the polypropylene insulated wire core 101 and improving the internal stress of the polypropylene insulated wire core 101. In addition, based on the thin shell theory of elasticity, a winding reel 1 with an appropriate diameter is selected, which not only reduces the internal stress of the polypropylene insulated wire core 101, but also avoids the waste of production materials caused by the excessively large diameter of the winding reel 1. Furthermore, the optimized design of the winding reel 1 gives the traditional winding reel 1 the function of flexibly adjusting its diameter, which can be used to wind insulated wire cores 101 with different diameters, making it more adaptable.

[0094] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a polypropylene insulated wire core, characterized in that: The method for manufacturing polypropylene insulated wire cores includes the following steps: S1: Molten material, which is the insulating raw material that is heated and melted, and then wrapped around the outer surface of the conductor by an extruder; S2: Temperature gradient design: The maximum temperature of the extruder is limited to 195℃. This temperature range can ensure the melt flowability of the insulating raw material and avoid thermal degradation. A six-segment gradient cooling system using cross-linked pipes is adopted, with the temperature of each segment controlled at 160℃→140℃→120℃→100℃→80℃→60℃, and each pipe segment is 3-5m long. The temperature is controlled and cooled by a combination of air cooling and water cooling. Extrusion line speed matching: The production line speed is controlled at 6-8m / min to ensure that the cooling rate of the insulation layer is ≤1.5℃ / s, and to avoid the stress of molecular chain freezing caused by sudden cooling; Aging treatment mechanism: A constant temperature aging zone of 60℃±2℃ is set in the end cooling section and maintained for 30 to 45 minutes. By utilizing the molecular chain segment movement characteristics of polypropylene with a glass transition temperature of Tg≈-10℃ or higher, the reconstruction of the crystallization zone is promoted, residual stress is released, and the volume shrinkage rate of the insulation layer is reduced to below 0.3%. S3: Rewinding, the inner radius of the reel (1) must meet the following requirements: R≥15D+ΔR, where D is the equivalent outer diameter of the insulated core (101), and ΔR is the safety margin ≥5mm; The winding reel (1) shown in S3 includes a rotating shaft (2). The rotating shaft (2) is symmetrically provided with adjustment components for adjusting the inner radius of the winding reel (1). Each adjustment component includes two hydraulic rods (3) symmetrically fixed to the rotating shaft (2). The output end of each hydraulic rod (3) points to the end of the rotating shaft (2), and the output ends of two adjacent hydraulic rods (3) are fixed with a ring (30). The ring (30) is sleeved on the rotating shaft (2) and can move along the axis of the rotating shaft (2). Each ring (30) has multiple push rods (4) rotatably connected to its outer ring. Each push rod (4) has an arc plate (5) at its end. The arc plates (5) are arranged in a circular array around the rotating shaft (2). The end of the arc plate (5) is provided with a disc-shaped side plate (6), and the side plate (6) is fixedly connected to the rotating shaft (2) along the same axis. The rotating shaft (2) has a through hole (13) inside, and a spindle (14) is provided inside the through hole (13). Multiple sets of protrusions (15) are symmetrically provided on the spindle (14), and two protrusions (15) in each set are symmetrically located on the outer surface of the spindle (14). Multiple sets of telescopic holes (16) are opened on the rotating shaft (2). Each set of telescopic holes (16) extends into the through hole (13). The two telescopic holes (16) in each set are opposite to each other. A limiting block (17) is provided in the telescopic hole (16). One end of the limiting block (17) protrudes out of the telescopic hole (16). A spring (18) is fixed to the other end of the limiting block (17). A pressing block (19) is fixed to the end of the spring (18). The pressing block (19) is arranged opposite to the protrusion (15) on the spindle (14). Both the pressing block (19) and the protrusion (15) are made of magnetic material. The protrusion (15) can attract the pressing block (19).

2. The method for manufacturing a polypropylene insulated wire core according to claim 1, characterized in that: Each of the arc-shaped plates (5) is fixed to a guide rod (7) at its end, and the axis of the guide rod (7) is set parallel to the axis of the rotating shaft (2); Multiple strip-shaped guide holes (8) are provided on each side plate (6). The guide holes (8) are arranged radially on the side plate (6), and the guide rod (7) is slidably connected to the guide rod (7).

3. The method for manufacturing a polypropylene insulated wire core according to claim 2, characterized in that: Multiple support plates (9) are fixedly connected to the outer ring of the middle of the rotating shaft (2) in a circular array. Two electric actuators (10) are symmetrically fixed to the end of each support plate (9). A plug plate (11) is fixed to the output end of each electric actuator (10). Each of the top rods (4) has multiple locking blocks (12) on its side wall, and the insert plate (11) can be inserted into the gap between two adjacent locking blocks (12).

4. The method for manufacturing a polypropylene insulated wire core according to claim 3, characterized in that: Each of the insert plates (11) is arranged in a U-shape and is inserted into the gap between two adjacent clips (12). The insert plates (11) are clamped on both sides of the top rod (4).

5. The method for manufacturing a polypropylene insulated wire core according to claim 1, characterized in that: A torsion spring (20) is sleeved in the middle of the mandrel (14). One end of the torsion spring (20) is fixed to the inner wall of the through hole (13), and the other end of the torsion spring (20) is fixed to the mandrel (14).

6. The method for manufacturing a polypropylene insulated wire core according to claim 2, characterized in that: The arc plate (5) has a notch (21) at one corner of its end and a notch (22) on its side. The notch (22) and the notch (21) are located on the same side of the end of the arc plate (5). A set screw (23) is provided in the notch (22). The set screw (23) is threaded through the arc plate (5) and extends into the notch (21). The end of the set screw (23) is rotatably connected to a top plate (24).

7. The method for manufacturing a polypropylene insulated wire core according to claim 2, characterized in that: Each of the two side plates (6) has a strip hole (25) and the strip holes (25) on the two side plates (6) are arranged opposite to each other. A pressing rod (26) is provided in the strip hole (25). The end of the pressing rod (26) extends to the outside of the side plate (6) and the end of the pressing rod (26) is fastened to the side plate (6) by a nut. Multiple locking blocks (27) are slidably connected to the extrusion rod (26). The surface of the locking block (27) is provided with an arc-shaped groove, which is used to extrude onto the surface of the cable.

8. A method for manufacturing a polypropylene insulated wire core according to claim 3, characterized in that: The rotating shaft (2) is symmetrically provided with support components. The support components are located near the end of the arc plate (5). The support components include multiple sleeves (28) perpendicular to the axis of the rotating shaft (2). The sleeves (28) are fixed to the rotating shaft (2). A rod (29) is sleeved inside the sleeve (28). The end of the rod (29) is fixed to the arc plate (5).

9. A method for manufacturing a polypropylene insulated wire core according to claim 1, characterized in that: Each section of the cross-linked pipe adopts a double-layer spiral flow guiding structure. The inner layer of each section of the cross-linked pipe is equipped with a ceramic wear-resistant coating, and the outer layer of each section of the cross-linked pipe is equipped with a PID intelligent temperature control module.

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