A two-core cable and a core manufacturing method

Abstract

This invention belongs to the field of cable manufacturing technology and discloses a two-core cable and a method for manufacturing the core. It includes: a primary stranded rope obtained by stranding a first filler rope according to a preset stranding pitch; two primary stranded ropes and two insulated cores arranged perpendicularly and intersecting, with a second filler rope filling the gaps, and stranded together to obtain a two-core cable core; and a two-core cable core consisting of a wrapping tape, an inner sheath, armor, and an outer sheath sequentially wrapped around the two-core cable core. This two-core stranded cable can effectively resist the continuous pressure exerted on the core during the cable manufacturing process, thereby reducing the cable's non-roundness and improving the quality of the two-core cable core.

Description

Technical Field

[0001] This invention relates to the field of cable manufacturing technology, and in particular to a two-core cable and a method for manufacturing the core. Background Technology

[0002] In cable manufacturing, cable roundness is one of the key indicators for evaluating product quality. Non-round cables are prone to torsional stress during installation, which can damage the insulation layer. Furthermore, their irregular shape hinders heat dissipation, potentially leading to localized overheating and shortening cable lifespan. For cables laid in conduits, non-roundness also increases the difficulty of installation.

[0003] Currently, when assembling two-core cables, a filler material (such as polypropylene tear film) is typically used to fill the gap between the two insulated cores, and then a wrapping tape is used to fix it to form a nearly circular cable core. However, this traditional method has significant drawbacks: the cable core subsequently needs to undergo processes such as extruding the inner sheath, wrapping with metal tape armor, and extruding the outer sheath. When passing through a tracked traction machine, the upward and downward compression transmission method exerts continuous pressure on the core. Because the filler material itself is compressible, the cable core is prone to deformation (flattening) after being compressed, and this deformation is fixed in subsequent processes. Especially in metal-tape armored cables, because the metal tape has no resilience, once the deformation occurs, it cannot be recovered, ultimately resulting in the finished cable exceeding the roundness standard.

[0004] Therefore, those skilled in the art are dedicated to developing a method for manufacturing two-core cables and their cores, so as to reduce the impact of compression on the two-core cables during the cabling process and ensure the roundness of the cables. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a two-core cable and a method for manufacturing the core.

[0006] To achieve the above objectives, the present invention provides a twisted rope comprising: The first filler rope is twisted according to a preset twisting pitch. In the formula, The diameter of the first filling rope, Where is the diameter of the primary stranding rope, k is the fill factor, and the fill factor ranges from 0.90 to 0.95; the preset stranding pitch is 4. ~8 Preferably 6 .

[0007] The present invention also provides a two-core cable core, comprising two primary stranded ropes as described in claim 1 and two insulated cores, wherein the diameter of the primary stranded ropes is... , This refers to the diameter of the insulated wire core; the diameter of the two-core cable core is 2. ;

[0008] In the gap between the insulated core and the primary stranded rope, multiple second filler ropes are arranged in parallel along the laying direction of the insulated core.

[0009] Preferably, the two primary stranded ropes and the two insulated wire cores are arranged perpendicularly and crosswise.

[0010] Preferably, the adjacent gaps between the insulated core and the primary stranded rope are filled with secondary stranded rope, and the remaining gaps are filled with multiple second filler ropes.

[0011] The outer side of the secondary strand is tangent to the outer side of the adjacent insulated core and the outer side of the primary strand, respectively. The diameter of the secondary strand is... .

[0012] Preferably, each secondary strand is made of It is made by twisting together the third filling rope. , The diameter of the secondary twisted rope. The diameter of the third filler rope.

[0013] The present invention also provides a two-core stranded cable, comprising any one of the above-mentioned two-core stranded wires and a wrapping tape, an inner sheath, an armor, and an outer sheath sequentially covering the two-core stranded wires.

[0014] The present invention also provides a method for manufacturing a two-core cable core, comprising: S1, determining the diameter of the primary stranded rope according to the diameter of the insulated core; S2, determining the number of first filler ropes required for each primary stranded rope, and calculating the diameter of the first filler ropes according to the number of first filler ropes and the diameter of the primary stranded ropes. In the formula, The diameter of the first filling rope, The diameter of the primary twisted rope. S3 represents the number of first filler ropes required for each primary strand, where k is the filler factor, ranging from 0.90 to 0.95; The first filler rope is twisted according to a preset twisting pitch to obtain a primary twisted rope. The preset twisting pitch is 4 to 8 times the diameter of the primary twisted rope, preferably 6 times. S4, two insulated wire cores and two primary twisted ropes are arranged perpendicularly and crosswise. Multiple second filler ropes are then filled in parallel along the laying direction of the insulated wire cores in the gaps between the insulated wire cores and the primary twisted ropes to obtain a rope with a diameter of 2... Two cores of the cable.

[0015] Preferably, S1 includes: calculating the diameter of the primary stranded rope based on the diameter of the insulated core and a first target formula, wherein the first target formula is: In the formula, d0 represents the diameter of the primary stranded rope, and d0 represents the diameter of the insulated core.

[0016] Preferably, the number of first filler ropes required for each primary strand is 4 to 10.

[0017] Preferably, before filling the gaps between the insulated core and the primary stranded rope with multiple second filler ropes in parallel along the laying direction of the insulated core, the method further includes: calculating the diameter of the secondary stranded rope based on the diameter of the insulated core and the diameter of the primary stranded rope, using Cartesian circle theorem; and calculating the number of third filler ropes required for each secondary stranded rope based on the diameter of the secondary stranded rope and the diameter of the third filler rope. , , The diameter of the secondary twisted rope. The diameter of the third filler rope used to form the secondary stranded rope is indicated; k is a fill factor ranging from 0.90 to 0.95; the secondary stranded rope is filled in the gap between the insulated core and the primary stranded rope along the laying direction of the insulated core, and multiple second filler ropes are filled in the remaining gap.

[0018] The beneficial effects of this invention are: by using the stranded rope obtained by pre-twisting the filler rope as a support skeleton, and combining it with conventional filler rope, a two-core stranded cable with high roundness is obtained, forming a cable filling system with stable structure and strong compressive strength, thus achieving the stringent engineering requirements for cable roundness. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a two-core stranded cable structure provided in an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of another two-core stranded cable structure provided in the embodiments of this application.

[0021] In the diagram, the primary stranded rope is 1, the first filler rope is a; the second filler rope is b, the third filler rope is c, the insulated core is 2, the conductor is 21, the insulation layer is 22, the wrapping tape is 3, the inner sheath is 4, the armor is 5, the outer sheath is 6, and the secondary stranded rope is 7. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that in the description of the present invention, terms such as "inner" and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These are used only for the convenience of describing the present invention and for 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 manner. Therefore, they should not be construed as limitations on the present invention. Terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In cable manufacturing, cable roundness is a key indicator for evaluating product quality. According to the State Grid standard Q / GDW 13244.1—2018, cable non-roundness should not exceed 15%, and some stringent engineering requirements stipulate a non-roundness of no more than 10%. Cable non-roundness is usually defined as (maximum outer diameter - minimum outer diameter) / maximum outer diameter. The minimum outer diameter is usually caused by the extrusion process during production. Although the uninsulated core of the cable is filled with filler rope, the compressibility of traditional filler materials cannot completely prevent deformation after the cable is compressed. Especially in the process of forming two-core cables, where the filler material accounts for a larger proportion, the non-roundness of the finished cable is more likely to exceed the standard.

[0024] Therefore, without changing the material of the filler, this application twists the originally loose filler ropes together, and the dense structure of the twisted ropes effectively supports the insulated core 2, ensuring that the cable cores maintain high roundness in subsequent processes, thereby obtaining high-quality two-core cable cores and two-core stranded cables.

[0025] like Figure 1 As shown, this embodiment provides a high-roundness two-core stranded cable, which includes two insulated cores 2, two pre-stretched primary strands 1, a first filler rope a to fill the gaps, and sequentially wrapped with a sheath 3, an inner sheath 4, an armor 5, and an outer sheath 6. The insulated cores 2 are composed of a conductor 21 and an insulation layer 22, and the diameter of the insulated cores 2 is [missing information]. The primary stranded rope 1 is formed by twisting N1 first filler ropes a according to a preset twisting pitch. The diameter D1 of the primary stranded rope 1 is given by the formula... Calculations are performed to ensure that the cable, after being formed, forms an internal structure with the insulated core 2 and the wrapping tape 3. It should be noted that the primary stranded rope 1 is formed by twisting multiple first filler ropes a, and its cross-section is not a regular circle. Therefore, in this embodiment, the diameter of the primary stranded rope 1 is the theoretical diameter, i.e., the diameter of the circumscribed circle. The secondary stranded rope 7 follows the same principle. The preset stranding pitch is 4. ~8 The optimal choice is 6 Lower limit 4 This ensures that the hinged body has sufficient tightness and structural stability, enabling it to withstand the pressure of the tracked tractor without significant deformation, thus fulfilling its function as an "internal skeleton"; upper limit 8 This avoids the loosening problem caused by excessive pitch, while ensuring good flexibility and production efficiency, and preventing damage to the filler rope due to excessive stretching; and the optimal twisting pitch of 6 is the golden balance point verified by extensive testing. At this pitch, the compressive strength, structural stability, flexibility and processability of the primary stranded rope 1 are all at their optimal levels, which can ensure that the cable core remains round to the greatest extent in subsequent processes.

[0026] The number N1 of the first filler rope a used for each primary stranding rope 1 is determined according to the formula. In the formula, The diameter of the first filling rope a is given, the filling factor k ranges from 0.90 to 0.95, and N1 preferably consists of 4 to 10 ropes (if...). If the value is less than 4, the cross-section of the primary stranded rope 1 is polygonal with poor roundness, making it unable to form a good internal connection with the insulated core 2. Furthermore, the support point coefficient and compressive strength are uneven. If the number of filler ropes is greater than 10, the strands of the primary stranded rope 1 are relatively loose, and the small filler ropes are easily squeezed together, leading to uncontrolled outer diameter and a drop in compressive strength. Therefore, the number of filler ropes a in the primary stranded rope 1 is controlled within the range of 4-10. This ensures that the stranded body has a round cross-section and a dense structure, while maintaining sufficient compressive rigidity to effectively support the insulated core 2 and ensure that the cable core maintains high roundness in subsequent processes. Here, k is used to correct the deviation between theoretical calculations and actual engineering applications caused by factors such as material elastic compression and mutual embedding during the stranding process of the first filler rope a. If k is less than 0.90, the stranded body structure is loose, the gaps between the filler ropes are too large, and the compressive strength is insufficient, failing to effectively support the insulated core 2 against compression deformation in subsequent processes. If k is greater than 0.95, the number of filler ropes is too large, resulting in excessive compression during stranding. This not only makes it difficult to accurately control the outer diameter of the stranded body but also easily leads to damage to the filler ropes and excessive internal stress, affecting process stability and product quality. By controlling k within the range of 0.90 to 0.95, the pre-stranded filler rope can have good structural compactness, compressive rigidity, and process feasibility, thereby ensuring the high roundness of the cable core.

[0027] Two insulated wire cores 2 are arranged perpendicularly to two primary stranded ropes 1, and multiple second filler ropes b are filled in parallel along the laying direction of the insulated wire cores 2 in the gap formed by the two, thereby forming a diameter of 2 The two-core cable is formed by sequentially wrapping the outer surface of the two-core cable with a wrapping tape 3, an extruded inner sheath 4, a wrapping metal tape armor 5, and an extruded outer sheath 6, ultimately resulting in a highly rounded two-core stranded cable. By cabling the two primary stranded ropes 1 together with the two insulated cores 2, it is equivalent to changing from a two-core cable to a four-core cable, with all four cores connected to the inner circle of the cable, forming a regular circular structure. In this embodiment, the pre-stretched primary stranded ropes 1 can be used as an internal skeleton, improving the density and rigidity of the filling material without changing the filling material, making it less prone to deformation under pressure. This effectively resists the extrusion deformation of equipment such as tracked traction machines in subsequent processes, fundamentally solving the problem of non-roundness of the cable caused by the high compressibility of traditional filling materials.

[0028] As one implementation method, a copper core cross-linked polyethylene insulated steel tape armored PVC sheathed power cable with model specification YJV22-0.6 / 1 2×95 is used as an example. The conductor 21 of the insulated core 2 is a compacted round stranded copper conductor 21 conforming to GB / T 3956, and the insulation layer 22 is made of silane cross-linked polyethylene. The diameter of the insulated core 2 is measured. It is 13.7mm, according to the formula The theoretical diameter of the primary stranded rope 1 was calculated. =2 / 3×13.7≈9.1mm, select a fill factor k of 0.95, and set the number of roots. The number of ropes is 4 to 10, and the equivalent diameter of the first filling rope a is calculated by reverse deduction. The range is 2.7mm to 4.5mm. Therefore, in this embodiment, a Φ4 type filling rope (its measured equivalent diameter is 3.7mm) can be selected as the first filling rope a. Substituting into the formula... Calculations yielded =0.95×(9.1 / 3.7) 2 ≈5.7, rounded to the nearest integer. =6 strands, the 6 Φ4 filler ropes are twisted together on the stranding machine at a pitch of 54mm (approximately 6×9.1mm) to obtain the primary stranded rope 1 with an actual outer diameter of 9.3mm (the error between the measured diameter and the theoretical diameter is within the allowable range). Then, two insulation strands are arranged perpendicularly to the two primary stranded ropes 1 mentioned above, and conventional polypropylene tear film filler rope (second filler rope b) is filled into the gap. After obtaining the cable core, it is sequentially wrapped with wrapping tape 3, extruded inner sheath 4, steel tape armor 5 and outer sheath 6 to make the finished cable.

[0029] In another embodiment, such as Figure 2As shown, secondary stranded ropes 7 are further filled into the four adjacent gaps formed by the perpendicular intersection of two insulated wire cores 2 and two primary stranded ropes 1. These secondary stranded ropes 7 are formed by twisting multiple third filler ropes c together, and their outer sides are tangent to the outer sides of the adjacent insulated wire cores 2 and the primary stranded ropes 1, respectively. According to Cartesian circle theorem, the diameter of the secondary stranded rope 7 can be calculated. The number of third filler ropes c required for each secondary stranded rope 7 From the formula Calculation determined, where The diameter of the third filler rope c is given, and the filler factor k is also taken as 0.90 to 0.95. In this embodiment, the calculation method for the twist pitch of the secondary twisted rope can be the same as that for the twist pitch of the first filler rope in the primary twisted rope, i.e., 4. ~8 6 preferred , and The same, of course, in practical applications, and Different methods are acceptable, and no restrictions are imposed here. After filling the four secondary stranded ropes 7, the remaining tiny gaps are filled with a conventional second filler rope b to ensure that the cross-section of the cable is completely and densely filled. Thus, by introducing the secondary stranded ropes 7, this embodiment further improves the uniformity and compressive rigidity of the filling system, enabling the cable core to maintain extremely high roundness even after undergoing multiple processes.

[0030] In one implementation, secondary stranded rope 7 is filled into the four adjacent gaps, and the diameter of the secondary stranded rope 7 is calculated according to the formula. (This is undoubtedly obtained by combining the diameter calculation formulas of the secondary stranded rope 7 and the primary stranded rope 1). ≈4.6mm, similarly selecting a fill factor k of 0.95, and choosing a diameter Given a third filler rope c of 2.0mm, calculate the number of secondary strands 7 required for each strand. Rounding to the nearest 5, the 5 third filler ropes c with a diameter of 2.0mm are twisted together to form a secondary twisted rope 7, which is then used to fill the four gaps. The remaining tiny gaps are then filled with the second filler rope b.

[0031] It should be noted that the first filling rope a, the second filling rope b, and the third filling rope c mentioned above can be the same, and their material can all be non-hygroscopic polypropylene tear film. Of course, in the specific implementation process, better materials can be selected, and there are no restrictions here.

[0032] This application also provides a method for manufacturing a two-core cable core, including the following steps:

[0033] S1. Determine the diameter of the primary stranded rope based on the diameter of the insulated wire core;

[0034] Specifically, based on the diameter of the insulated wire core and the first objective formula Calculate the diameter of the primary stranded rope. .

[0035] S2, determine the number of first filler ropes required for each primary strand, and calculate the diameter of the first filler ropes based on the number of first filler ropes and the diameter of the primary strands. In the formula, The diameter of the first filling rope, The diameter of the primary twisted rope. The first filler rope is the number of ropes required for each primary strand, and k is the filler factor, which ranges from 0.90 to 0.95.

[0036] The number of first filler ropes required for each primary twisted rope is 4 to 10.

[0037] Specifically, the range of possible first filler rope diameters can be calculated based on the range of filler factor and the range of the number of first filler ropes required for each primary strand, and filler rope specifications within the diameter range can be selected from the existing filler rope library based on the first filler rope diameter range.

[0038] S3, will The first filling rope is twisted according to a preset twisting pitch to obtain a primary twisted rope. The preset twisting pitch is 4 to 8 times the diameter of the primary twisted rope, preferably 6 times.

[0039] S4, arrange two insulated wire cores and two primary stranded ropes perpendicularly and crosswise, and fill the gaps between the insulated wire cores and primary stranded ropes with multiple second filler ropes in parallel along the laying direction of the insulated wire cores, resulting in a diameter of 2. Two cores of the cable.

[0040] As a further preferred embodiment of this method, before filling the gaps between the insulated core and the primary stranded rope with multiple second filler ropes in parallel along the laying direction of the insulated core, it is also possible to: calculate the diameter of the secondary stranded rope based on the diameter of the insulated core and the diameter of the primary stranded rope, using Cartesian circle theorem; and calculate the number of third filler ropes required for each secondary stranded rope based on the diameter of the secondary stranded rope and the diameter of the third filler rope. , , The diameter of the secondary twisted rope. The diameter of the third filler rope used to form the secondary stranded rope is indicated; k is a fill factor ranging from 0.90 to 0.95; the secondary stranded rope is filled in the gap between the insulated core and the primary stranded rope along the laying direction of the insulated core, and multiple second filler ropes are filled in the remaining gap.

[0041] Two insulated wire cores and two primary stranded ropes are arranged vertically and symmetrically, and a second filler rope is filled into the gaps to form a cable. Subsequent processes are carried out in the conventional manner, including inner sheath extrusion, steel tape armoring, and outer sheath extrusion, to obtain a two-core stranded cable.

[0042] To verify the technical effect of this application, YJV22-0.6 / 1 2×95 cables of the same specification were manufactured using the method of this application (two primary stranded ropes and two insulated cores to form a four-strand stranded cable) and the traditional method (directly using loose filler rope). The key performance indicators of the two-core stranded cable and the traditional finished cable were compared and tested.

[0043] 1. Deformation recovery capability of cable core

[0044] To simulate the compression condition of the cable core by the tracked traction machine during cable manufacturing, the cable cores obtained by the method of this application and the cable cores obtained by the conventional method were placed under a pressure testing machine and a pressure of 0.5 MPa (simulating the actual pressure of the tracked traction machine) was applied. After holding the pressure for 30 seconds, the pressure was released, and the deformation rate was measured. According to the formula: Deformation rate = (outer diameter after compression - original outer diameter) / original outer diameter × 100%, the following table 1 is obtained.

[0045] Table 1. Comparison of cable core deformation rates obtained by traditional methods and methods of this application.

[0046] Test Project Traditional methods This application method outer diameter before compression 28.4mm 28.4mm outer diameter after compression 24.8mm 26.6mm Deformation rate 12.3% 6.3%

[0047] Test results show that the deformation rate of the cable core manufactured by the traditional method is as high as 12.3%, while the deformation rate of the cable core manufactured by the method of this application is only 6.3%. This indicates that the pre-stretched filler rope used in this application does indeed play the supporting role of the "internal skeleton" and effectively resists external pressure.

[0048] 2. Out-of-roundness of stranded cables

[0049] According to the method specified in GB / T 2951.11—2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Cables", five samples with different cross-sections were selected on the finished cables corresponding to the two methods. The maximum and minimum outer diameters were measured respectively. The out-of-roundness was calculated according to: Out-of-roundness = (Maximum outer diameter - Minimum outer diameter) / Maximum outer diameter × 100%. The maximum value and average value were taken as the test results, and Table 2 was obtained.

[0050] Table 2. Test results of non-roundness of stranded cables obtained by conventional method and method of this application.

[0051] project Traditional methods This application method Sample 1 11.5% 5.4% Sample 2 17.3% 7.3% Sample 3 14.8% 8.6% Sample 4 13.9% 7.8% Sample 5 14.2% 4.2% Maximum out-of-roundness 17.3% 8.6% Average out-of-roundness 14.3% 6.7%

[0052] Test results show that the cable manufactured using the method of this invention has a maximum out-of-roundness of only 8.6% and an average out-of-roundness of 6.7%, which is far superior to the State Grid standard (≤15%) and meets stringent engineering requirements (≤10%). Its compression resistance is also far superior to traditional cable filling methods. This fully demonstrates the significant beneficial effects of this application in improving cable roundness and compressive strength.

[0053] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A primary stranded rope, characterized in that, include: a first filler rope twisted with a preset twist pitch, wherein, is the diameter of the first filler rope, is the diameter of the primary twisted rope, and k is a filling factor, the filling factor being in the range of 0.90 to 0.95; The preset twist pitch is 4. ~8 Preferably 6 .

2. A two-core cable core, characterized in that, It includes two primary stranded ropes as described in claim 1 and two insulated wire cores, wherein the diameter of the primary stranded ropes is... , The diameter of the insulated wire core is 2, and the diameter of the two-core cable core is 2. ; In the gap between the insulated wire core and the primary stranded rope, multiple second filler ropes are arranged in parallel along the laying direction of the insulated wire core.

3. The two-core cable core according to claim 2, characterized in that, The two primary stranded ropes and the two insulated wire cores are arranged perpendicularly and cross each other.

4. The two-core cable core according to claim 3, characterized in that, The adjacent gaps between the insulated wire core and the primary stranded rope are filled with secondary stranded rope, and the remaining gaps are filled with multiple second filler ropes. The outer side of the secondary stranded rope is tangent to the outer side of the adjacent insulated wire core and the outer side of the primary stranded rope, respectively. The diameter of the secondary stranded rope... = .

5. The two-core cable core according to claim 4, characterized in that, Each of the aforementioned secondary strands is composed of It is made by twisting together the third filling rope. , The diameter of the secondary twisted rope is [missing information]. The diameter of the third filling rope.

6. A two-core stranded cable, characterized in that, It includes the two-core cable core as described in any one of claims 2 to 5, and the wrapping tape, inner sheath, armor, and outer sheath that sequentially cover the two-core cable core.

7. A method for manufacturing a two-core cable core, characterized in that, include: S1. Determine the diameter of the primary stranded rope based on the diameter of the insulated wire core; S2, determine the number of first filler ropes required for each primary strand, and calculate the diameter of the first filler ropes based on the number of first filler ropes and the diameter of the primary strand. In the formula, The diameter of the first filling rope is [missing information]. The diameter of the primary stranded rope is given. The number of first filler ropes required for each of the primary stranded ropes, where k is the filler factor, and the filler factor ranges from 0.90 to 0.95; S3, will The first filler rope is twisted according to a preset twisting pitch to obtain a primary twisted rope. The preset twisting pitch is 4 to 8 times the diameter of the primary twisted rope, preferably 6 times. S4, arrange the two insulated wire cores and the two primary stranded ropes perpendicularly and crosswise, and fill the gaps between the insulated wire cores and the primary stranded ropes with multiple second filler ropes in parallel along the laying direction of the insulated wire cores, to obtain a diameter of 2. Two cores of the cable.

8. The manufacturing method according to claim 7, characterized in that, S1 includes: The diameter of the primary stranded rope is calculated based on the diameter of the insulated core and the first target formula, wherein the first target formula is: In the formula, d0 represents the diameter of the primary stranded rope, and d0 represents the diameter of the insulated wire core.

9. The manufacturing method according to claim 7, characterized in that, The number of first filler ropes required for each primary stranded rope is 4 to 10.

10. The manufacturing method according to claim 7, characterized in that, Before filling the gap between the insulated wire core and the primary stranded rope with multiple second filler ropes in parallel along the laying direction of the insulated wire core, the method further includes: Based on the diameter of the insulated core and the diameter of the primary stranded rope, and using Cartesian circle theorem, the diameter of the secondary stranded rope is calculated. Calculate the number of third filler ropes required for each secondary stranded rope based on the diameter of the secondary stranded rope and the diameter of the third filler rope. , , The diameter of the secondary twisted rope is [missing information]. The diameter of the third filler rope used for twisting to form the secondary twisted rope is indicated; k is the filler factor in the range of 0.90 to 0.

95. The secondary stranded rope is filled into the gap between the insulated core and the primary stranded rope along the laying direction of the insulated core, and multiple second filler ropes are filled into the remaining gap.

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