Crosslinked polyethylene flexible conductor insulated cable and method of making same

Abstract

This invention provides a cross-linked polyethylene flexible conductor insulated cable and its preparation method. The invention relates to the field of cable technology, comprising a flexible conductor and an interlocking armor layer sleeved on the outside of the flexible conductor. The interlocking armor layer includes a strip-shaped main body, with a first locking part on a first side and a second locking part on a second side. The first and second locking parts are located on different sides of the two sides, and the stiffness of the first locking part is greater than that of the second locking part. This invention achieves cable bending at small angles through gap sliding adaptation and bending at large angles through elastic deformation buffering adaptation of the second locking part. The locking mechanism maintains a stable engagement state throughout the bending process, balancing the mechanical protective stiffness of the armor layer with the bending performance of the cable, thus improving the operational reliability of the armor layer.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and more particularly to cross-linked polyethylene soft conductor insulated cables and their preparation methods. Background Technology

[0002] Installing metal armor strips on the outside of flexible conductor cables can provide rigid protection and effectively prevent outdoor cables from being damaged by wild animals or mechanical forces.

[0003] Prior art document 1 (CN210777970U) discloses an armored cable. The armor tape is a continuous straight tape structure. The two sides of the straight tape are punched in opposite directions to form an inner bend and an outer bend. The inner bend and the outer bend are interlocked to form an interlocking armor layer. The locking buckles on both sides of the armor tape are rigid bending structures. The cable bending deformation is achieved by the pre-reserved gap between the locking buckles. The armor tape is spirally wound and wrapped around the outside of the cable core. The mechanical protection of the internal cable core is achieved by the interlocking of the metal locking buckles. It has high compressive strength.

[0004] The Z-type armored tape in the comparison document has a rigid bending structure with equal stiffness for both the inner and outer bends. The bending stiffness of the buckles on both sides is the same. The cable bending is achieved by the slippage of the buckle assembly gap alone. It lacks a buckle structure that can be elastically deformed as a buffer. Under large-angle bending conditions, the buckles are prone to hard contact jamming, which may cause the buckles to disengage and create a protective gap.

[0005] Prior art document 2 (CN207517419U) discloses an aluminum alloy interlocked armored cable. The cable consists of a cable body, an insulation layer, a waterproof layer, a flame-retardant layer, an interlocked armor layer, and an outer sheath. The interlocked armor layer is composed of multiple interlocking units connected end to end. The connecting part of the interlocking unit has a first interlocking part and a second interlocking part integrally formed at both ends. The second interlocking part is rotatably disposed inside the first interlocking part. A bending part is provided between the second interlocking part and the connecting part. The bending range of the cable is increased by relying on the relative rotation between the interlocking parts and the bending part. At the same time, anti-slip protrusions are provided on the inner wall of the connecting part to prevent the armor layer from disengaging. Steel wires are added inside the flame-retardant layer to increase the overall tensile strength of the cable, thereby improving the problems of insufficient tensile strength and inconvenient bending of traditional interlocked armor.

[0006] However, the interlocking units on both sides of the interlocking unit in the comparison document are rigid structures, and the cable bending is achieved only by the rotational cooperation between the interlocking parts and the bending part. The locking itself does not have elastic deformation capability, and there is a lack of elastic buffer margin when bending at a large angle, which can easily cause the locking to jam. Long-term operation can easily lead to problems such as the expansion of the armor engagement gap and the decrease in protection reliability. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a cross-linked polyethylene soft conductor insulated cable and its preparation method. This invention achieves the effect of using gap sliding adaptation for small-angle bending and using elastic deformation buffer adaptation of the second locking part for large-angle bending. The locking maintains a stable engagement state throughout the bending process, taking into account both the mechanical protection stiffness of the armor layer and the bending performance of the cable, thereby improving the working reliability of the armor layer.

[0008] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0009] A cross-linked polyethylene flexible conductor insulated cable includes a flexible conductor and an interlocking armor layer sleeved on the outside of the flexible conductor. The interlocking armor layer includes a strip-shaped main body. A first locking part is provided on a first side of the strip-shaped main body, and a second locking part is provided on a second side. The first locking part and the second locking part are located on different sides of the two sides, and the stiffness of the first locking part is greater than that of the second locking part.

[0010] The aforementioned interlocking armor layer is spirally fitted onto the outside of the flexible conductor along its length, providing protection to the outer side and preventing mechanical damage. Furthermore, the first and second locking parts, with their different rigidities, can cooperate and stably engage, forming a stable engagement area that provides comprehensive protection for the flexible conductor. During cable bending, the pre-existing gap between the first and second locking parts can adjust to accommodate smaller bending angles. At larger bending angles, the relatively flexible second locking part can deform under external force to accommodate even larger bending angles. It should be noted that even at larger bending angles, there is a certain overlap between the first and second locking parts, maintaining a stable engagement to prevent gaps that could compromise protection. This arrangement, by pre-reserving the necessary gap and elasticity for bending, not only provides effective and comprehensive protection but also meets the requirements for different bending angles during installation.

[0011] Preferably, the first locking part and the second locking part are made of the same material, and the second locking part is more likely to undergo elastic cantilever deformation.

[0012] Preferably, the first locking part includes a first connecting part and a first overlapping part, and the second locking part includes a second connecting part and a second overlapping part. The first locking part and the second locking part have the same length, and the thickness of the first connecting part is less than the thickness of the second connecting part.

[0013] The thickness of the strip body is completely consistent at all locations. The thickness of the first connecting part and the second connecting part refers to the cross-sectional thickness of the part perpendicular to the strip body after bending, that is, the cross-sectional height when placed horizontally.

[0014] Preferably, the width of the first overlapping portion is greater than the width of the second overlapping portion, where the width refers to the cross-sectional width of the portion that is parallel or relatively parallel to the strip body after bending.

[0015] Preferably, the space between the first locking part and the second locking part is filled with lubricating grease.

[0016] The lubricating grease located between the first and second locking parts should be a high-viscosity, anti-leakage, anti-fretting wear, rust-proof, anti-oxidation, and compatible with armor metal and cable inner lining. This grease can continuously form a stable oil film during the relative sliding and elastic deformation of the locking parts, reduce the generation of metal shavings at the locking parts' engagement position, inhibit electrochemical corrosion of the metal contact surface, and is not easily affected by changes in cable operating temperature, thus ensuring long-term lubrication and protection of the locking parts. For example, composite lithium-based extreme pressure grease or perfluoropolyether grease can be used.

[0017] A method for preparing cross-linked polyethylene (XLPE) flexible conductor insulated cable, comprising the following steps:

[0018] S1. A copper wire conductor of a predetermined diameter is stranded together. A cross-linked polyethylene insulation layer is extruded on the outside of the copper wire conductor. First, polyethylene granules are melted at high temperature through an extruder and continuously extruded onto the outer surface of the conductor after straightening and preheating to form a dense insulation blank layer. Then, the linear polyethylene molecules are cross-linked through cross-linking to transform into a three-dimensional network cross-linked polyethylene structure, eliminating the defect of polyethylene being easy to melt and flow when heated. According to the cross-linking method, it is divided into three categories: chemical cross-linking, silane cross-linking, and irradiation cross-linking. Chemical cross-linking is mostly used in high-voltage power cable scenarios. During extrusion, a three-layer co-extrusion die head is used to simultaneously extrude the inner shielding layer, the cross-linked polyethylene insulation layer, and the outer shielding layer to ensure that the interfaces of each layer are tight and without air gaps. Medium and high voltage YJVR cables generally use chemical cross-linking catenary extrusion cross-linking process to complete the insulation coating.

[0019] S2. Multiple coated copper conductors are fed into the cable forming machine and spirally stranded according to the specified pitch. Simultaneously, filler material is fed into the gaps between the conductors to form a filler layer, thereby filling the gaps between the conductors and making the overall cross-section of the cable core more rounded, inhibiting the conductors from moving and squeezing each other. After stranding, a flexible isolation layer is wrapped around the outside of the cable core using a wrapping machine in a spiral overlapping manner. During the wrapping process, the tension of the tape and the overlap rate are controlled to ensure that the isolation layer is continuous and complete and does not excessively tighten the cable core. This flexible isolation layer separates the cable core from the subsequent armor structure, preventing the armor metal tape from directly scratching the insulated conductors. For example, the filler layer can be made of polypropylene fiber filler rope, and the flexible isolation layer can be made of polyester non-woven tape.

[0020] S3. After the cable core has been processed through cabling, filling layer, and flexible isolation layer, it continues to be conveyed forward. The interlocking armor metal strip first undergoes straightening, cleaning, and grease injection pretreatment processes. The first locking part and the second locking part are formed by stamping or pre-bending on both sides of the metal strip. Then, the interlocking armor forming mold spirally wraps the metal strip around the outer surface of the flexible isolation layer. During the spiral winding process, the first locking part and the second locking part on the adjacent sides are interlocked and engaged in sequence. The first locking part and the second locking part on the bottom side can be controlled to be in close contact and engaged first, and then the first locking part and the second locking part on the top side can be controlled to be in close contact and engaged. During the continuous winding process, the engagement and locking are continuously performed. The overlap and tightness of the locking buckle are controlled by the radial pressure of the interlocking armor forming mold to ensure that the locking buckle is neither too tight to hinder cable bending nor too loose to cause loosening. After the engagement is completed, the outer diameter of the armor is trimmed by the shaping mold to achieve continuous forming of the interlocking armor layer. The above interlocking armor processing can be completed using aluminum alloy armor strip.

[0021] The interlocking armor forming mold is a modular combination mold, which includes a pre-forming pressure roller group, a forming hook mold, and a sizing and shaping mold. The pre-forming pressure roller group is used to pre-bend both sides of the armor metal strip to form the first locking part and the second locking part respectively. The forming hook mold guides the metal strip to spirally wrap around the outer surface of the flexible isolation layer and make the two locking parts interlock and bite each other. The sizing and shaping mold shapes the outer diameter of the interlocking armor layer after interlocking and suppresses the buckle from springing back and loosening. For example, an adjustable aluminum alloy interlocking armor forming mold adapted to the cross section of the asymmetrical buckle can be used.

[0022] S4. After the interlocking armor layer is snapped together, the cable core continues to move forward. First, it undergoes outer diameter inspection and visual inspection to check for defects such as mis-stitching, loosening, and warping of the interlocking clips. Then, an outer sheath layer is extruded or wrapped around the outside of the interlocking armor layer. The outer sheath completely covers the interlocking armor layer to isolate it from external moisture, oil, and mechanical damage. After the sheath processing is completed, it goes through a cooling water bath for cooling and shaping, a spark withstand voltage test to check for sheath breakdown points, and then the outer diameter is re-measured and the meter is marked. Finally, it is pulled and wound into a finished cable reel. If necessary, the finished product can also be sampled for type testing such as bending test and compression test. For example, the outer sheath can be made of polyvinyl chloride or polyethylene.

[0023] Preferably, the cleaning and grease injection step S3 uses a cross-linked polyethylene soft conductor insulated cable processing equipment. The cross-linked polyethylene soft conductor insulated cable processing equipment includes a cleaning device and a grease injection device. The grease injection device is located downstream of the processing route of the cleaning device. The grease injection device includes a grease injection gun, a suction positioning component located behind the grease injection gun, and a one-way conveying device located between the grease injection gun and the suction positioning component. A particle monitoring device is provided between the one-way conveying device and the suction positioning component.

[0024] Grease can be injected into the second locking part through the grease injection gun. The second locking part is positioned during the conveying process by the suction and positioning component. At the same time, excess grease is evenly filled and suctioned. The particle monitoring device can monitor the content of debris particles in the suctioned and recovered grease in real time. When the debris content of the suctioned and recovered grease exceeds the set threshold limit, the cleaning status of the cleaning device is checked in time to ensure that the overall equipment can clean and fill grease normally and stably.

[0025] Preferably, the suction positioning assembly includes a suction positioning disk, the side wall of which has suction holes, and a drive shaft with an external power source is fixed to the side wall of the suction positioning disk. The drive shaft is hollow to form a conveying channel. The first side of the conveying channel is connected to multiple suction holes, and the second side is connected to a unidirectional conveying device through a rotating connector. The particle monitoring device is located between the rotating connector and the unidirectional conveying device.

[0026] When a suction positioning plate is selected, an arc-shaped sealing block is fixed on the inner wall of the suction positioning plate. This block can cover the suction hole that has deflected to the top, ensuring that the suction hole at the bottom is within a stable suction pressure range, thus achieving effective suction. A positioning bracket is set in the middle of the arc-shaped sealing block. The positioning bracket is fixed to the fixed workpiece on the outside through the hollow interior, ensuring the relative position of the arc-shaped sealing block during the rotation of the suction positioning plate.

[0027] Preferably, the unidirectional conveying device includes a conveying housing, inside which a unidirectional partition plate is fixed and a negative pressure generator is movably arranged. A transfer chamber is formed between the negative pressure generator and the unidirectional partition plate, and a storage chamber is formed between the unidirectional partition plate and the conveying housing. The transfer chamber and the storage chamber are connected by a first conveying connector with a built-in first one-way valve, and the transfer chamber is connected to a suction positioning assembly by a second conveying connector with a built-in second one-way valve.

[0028] The transfer chamber is periodically controlled by a negative pressure generator to be in a negative or positive pressure state. Excess grease from the suction positioning component is drawn into the transfer chamber and then forced into the storage chamber, finally being ejected from the grease gun. The grease gun includes a nozzle and a barrel. The barrel extends to the bottom of the storage chamber from the side away from the nozzle. An elastic and retractable pressure storage device, such as an elastic piston or an elastic air bladder, can be installed in the storage chamber to maintain a relatively constant pressure state. This allows for the storage of excess grease and subsequent continuous and uniform ejection from the grease gun, achieving stable grease injection.

[0029] The aforementioned negative pressure generator can be a combination of a negative pressure piston and a reciprocating power rod. During the liposuction process, the reciprocating power rod drives the negative pressure piston to move up and down repeatedly. During the reciprocating movement of the negative pressure piston, the transfer chamber is periodically alternated between positive and negative pressure states to achieve pressure control.

[0030] Preferably, the cleaning device includes an air blowing assembly, a suction assembly is provided between the air blowing assembly and the grease injection device, and a one-way air pumping device is provided between the air blowing assembly and the suction assembly. A filter assembly is installed in the one-way air pumping device, and the gas continuously sucked by the suction assembly is pumped one-way to one side of the air blowing assembly for air spraying.

[0031] The blowing component is located at the bending position, which can continuously blow air to remove debris generated during the bending process. The suction component is located at the non-bending position, which can continuously suction the inside of the stable locking groove under negative pressure, minimizing the content of particulate matter in the locking groove.

[0032] The aforementioned blowing and suction components can be designed with reference to the suction positioning plate, which can clean while also positioning to ensure stable delivery.

[0033] The beneficial effects of this invention are as follows:

[0034] Compared with existing technologies, this application solves the problems of existing technologies where both locking parts are rigid structures with equal stiffness, relying solely on assembly gaps for bending. This results in a lack of elastic buffering margin for large-angle bending, which easily leads to locking jamming, loosening, and the creation of protective gaps. The new technology achieves cable bending at small angles by relying on gap sliding for adaptation, and bending at large angles by relying on the elastic deformation buffering of the second locking part for adaptation. The locking parts maintain a stable engagement state throughout the bending process, balancing the mechanical protective stiffness of the armor layer with the bending performance of the cable, thus improving the operational reliability of the armor layer. Attached Figure Description

[0035] Figure 1 This is a three-dimensional structural diagram of the cable processing process of the present invention.

[0036] Figure 2 For the present invention Figure 1 A schematic diagram of the main structure.

[0037] Figure 3 For the present invention Figure 1 A side view structural diagram.

[0038] Figure 4 For the present invention Figure 3A magnified structural diagram at point A.

[0039] Figure 5 This is a schematic diagram of the internal structure of the interlocking armor layer of the present invention.

[0040] Figure 6 This is a three-dimensional structural diagram of the cross-linked polyethylene soft conductor insulated cable processing equipment of the present invention.

[0041] Figure 7 For the present invention Figure 6 A schematic diagram of the main structure.

[0042] Figure 8 For the present invention Figure 6 A top-view structural diagram.

[0043] Figure 9 For the present invention Figure 8 A magnified structural diagram at point B.

[0044] Figure 10 This is a schematic diagram of the internal structure of the unidirectional conveying device of the present invention.

[0045] Figure 11 This is a process flow diagram of the present invention.

[0046] In the diagram: 100, copper wire conductor; 110, trapezoidal copper wire; 120, round copper wire; 200, cross-linked polyethylene insulation layer; 300, filler layer; 400, flexible insulating layer; 500, interlocking armor layer; 501, bottom side; 502, top side; 510, first locking part; 511, first connecting part; 512, first overlapping part; 520, second locking part; 521, second connecting part; 522, second overlapping part; 530, strip-shaped body; 600, cleaning device; 610, air blowing assembly; 620, suction assembly; 63 0. One-way air pump; 631. Filter assembly; 700. Grease injection device; 710. Grease injection gun; 711. Gun head; 712. Gun barrel; 720. Suction positioning assembly; 721. Suction positioning plate; 722. Suction hole; 723. Drive shaft; 724. Rotary connector; 725. Second conveying joint; 730. One-way conveying device; 731. Reciprocating power rod; 732. Conveying housing; 733. Negative pressure piston; 734. First conveying joint; 735. One-way partition plate; 736. Transfer chamber; 737. Storage chamber; Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0048] See attached document Figure 1 -Appendix Figure 5This invention provides a cross-linked polyethylene flexible conductor insulated cable, including a flexible conductor and an interlocking armor layer 500 sleeved on the outside of the flexible conductor. The flexible conductor includes, from the inside out, a copper wire conductor 100, a cross-linked polyethylene insulation layer 200, a filler layer 300, and a flexible isolation layer 400. The copper wire conductor 100 can be formed by stranding multiple copper wires with circular cross sections, or it can be formed by stranding copper wires with irregular cross sections. The irregular copper wires include a circular copper wire 120 located in the center and trapezoidal copper wires 110 located on the upper and lower sides of the circular copper wire 120 with arc-shaped surfaces. Multiple trapezoidal copper wires 110 are stranded on the outside of the circular copper wire 120 to form a circular cable with a larger cross-sectional size.

[0049] The interlocking armor layer 500 includes a strip-shaped main body 530. A first locking part 510 is provided on the first side of the strip-shaped main body 530, and a second locking part 520 is provided on the second side. The first locking part 510 and the second locking part 520 are located on different sides of the two bodies. The stiffness of the first locking part 510 is greater than that of the second locking part 520. Under external force, the first locking part 510 is less prone to elastic deformation, while the second locking part 520 can produce a small amount of elastic deformation. The first locking part 510 is a rigid locking part, ensuring proper interlocking and locking. During the process, the shape of the first locking part 510 remains relatively unchanged, while the second locking part 520 can undergo a slight elastic deformation; the interlocking armor layer 500 is spirally fitted onto the outside of the soft conductor along the length of the soft conductor, which can protect the soft conductor at the outer position to avoid mechanical damage; and the first locking part 510 and the second locking part 520 with different rigidities can cooperate with each other to form a stable interlocking area, which can achieve full coverage protection for the soft conductor.

[0050] During cable bending, when the bending angle is small, the reserved gap between the first locking part 510 and the second locking part 520 can move and change to meet the cable bending arrangement requirements. When the bending angle is large, the relatively flexible second locking part 520 can deform to a certain extent under the action of external force to meet the needs of larger bending angles. It should be noted that when bending at a large angle, there is a certain overlap margin between the first locking part 510 and the second locking part 520. The first locking part 510 and the second locking part 520 are still in a stable interlocking protection state to avoid gaps that would prevent protection. Through the above arrangement method, the gap margin and elasticity margin required for bending are reserved in advance, which can meet the arrangement requirements of different bending angles during the arrangement process while ensuring effective and comprehensive protection.

[0051] By setting up a first locking part 510 and a second locking part 520 with different stiffness in the interlocking armor layer 500, and providing a core structure with reserved bending gaps and overlapping allowances, compared with the existing symmetrical interlocking armor method with rigid locking on both sides and no elastic deformation allowance, this method achieves a graded bending effect where small-angle bending of the cable relies on gap sliding adaptation, and large-angle bending relies on elastic deformation adaptation of the flexible locking part. It takes into account both the overall structural protection stiffness of the interlocking armor layer 500 and the flexible bending performance of the cable, maintaining a tight interlocking with no protective gap throughout the process, effectively adapting to different bending conditions in complex scenarios, and avoiding the problems of jamming, loosening, and missing protection in traditional rigid armor bending.

[0052] The first locking part 510 and the second locking part 520 can be made of different materials to achieve different effects of softness and hardness; the present invention selects the first locking part 510 and the second locking part 520 to be made of the same material, and the second locking part 520 is more likely to undergo elastic cantilever deformation.

[0053] The core structure of the second locking part 520, which is made of the same material but relies on structural differences to achieve elastic cantilever deformation, is compared with the existing armor locking method that achieves a combination of rigidity and flexibility by changing different materials. It achieves the effect of uniform material molding and structurally differentiated rigidity and flexibility, avoiding the defects of difficult processing, poor material compatibility, and inconsistent thermal expansion and contraction of composite molding of dissimilar materials. It ensures the overall mechanical consistency and molding stability of the interlocking armor layer 500, while accurately realizing the local elastic buffering function of the buckle.

[0054] Specifically, the first locking part 510 includes a first connecting part 511 and a first overlapping part 512, and the second locking part 520 includes a second connecting part 521 and a second overlapping part 522. The first locking part 510 and the second locking part 520 have the same length, and the thickness of the first connecting part 511 is less than the thickness of the second connecting part 521. The thickness of each position of the strip body 530 is completely consistent. The thickness of the first connecting part 511 and the second connecting part 521 refers to the cross-sectional thickness of a portion of the strip body 530 that is perpendicular to it after bending, i.e., the cross-sectional height in the horizontally placed state.

[0055] By using the core structure with a uniform thickness of the strip-shaped main body 530 and differentiated thickness of the connecting parts of the locking parts on both sides, compared with the existing symmetrical design of armor belt locking parts with uniform thickness and no structural stiffness differentiation, it achieves the effect of precisely controlling the bending stiffness of the locking parts on both sides under the same material and overall specifications. It does not require changing the overall specifications and dimensions of the armor belt, and only the difference in thickness of the local bending section is used to form the distinction between rigid and flexible parts. The structure is simple and easy to process, and effectively ensures the support and protection performance of the rigid locking part and the elastic deformation capability of the flexible locking part.

[0056] Furthermore, the width of the first overlapping portion 512 is greater than the width of the second overlapping portion 522. The aforementioned width refers to the cross-sectional width of the portion that is parallel to or relatively parallel to the strip body 530 after bending.

[0057] By using the core structure where the width of the first overlapping part 512 is greater than the width of the second overlapping part 522, compared with the symmetrical interlocking method where the overlap width of the locking parts on both sides is the same in the prior art, a larger overlapping coverage area on the rigid side and a wider interlocking support range are achieved, which improves the interlocking stability and overall pressure resistance. At the same time, it matches the working characteristics of small deformation and slippage on the flexible side, avoiding the problem of disengagement and gaps due to insufficient overlap during bending, and further balancing the protective performance and bending flexibility of the interlocking armor layer 500.

[0058] Furthermore, a lubricating grease is filled between the first locking part 510 and the second locking part 520. The lubricating grease between the first locking part 510 and the second locking part 520 should be a grease with high viscosity, anti-leakage, anti-fretting wear, rust prevention and oxidation resistance, and good compatibility with armor metal and cable inner lining. This grease can continuously form a stable oil film during the relative sliding and elastic deformation of the latch, reduce the generation of metal wear debris at the locking part engagement position, inhibit electrochemical corrosion of the metal contact surface, and is not easily affected by changes in cable operating temperature to cause flow or oil separation and loss, ensuring long-term lubrication and protection of the latch part. For example, a composite lithium-based extreme pressure grease or a perfluoropolyether grease can be selected.

[0059] By filling the interlocking areas on both sides with suitable lubricating grease, the core structure achieves continuous oil film protection during the sliding and elastic deformation of the lock, compared with the existing interlocking armored locks that rely solely on rigid metal contact without dedicated lubrication protection. This effectively reduces fretting wear, minimizes metal debris generation, and inhibits electrochemical corrosion and oxidation at the interlocking position. It also adapts to changes in cable temperature conditions, preventing grease loss and failure, and significantly improves the service life and long-term operational stability of the armored lock.

[0060] The present invention will be further described below with reference to specific preparation methods.

[0061] See attached document Figure 6 -Appendix Figure 11 The present invention also provides a method for preparing a cross-linked polyethylene flexible conductor insulated cable, for use in the above-mentioned cross-linked polyethylene flexible conductor insulated cable, comprising the following steps:

[0062] S1. A copper wire conductor 100 of a predetermined diameter is stranded together. A cross-linked polyethylene insulation layer 200 is extruded on the outside of the copper wire conductor 100. First, polyethylene granules are melted at high temperature through an extruder and continuously extruded onto the outer surface of the conductor after straightening and preheating to form a dense insulation blank layer. Then, through cross-linking, the linear polyethylene molecules undergo a cross-linking reaction to transform into a three-dimensional network cross-linked polyethylene structure, eliminating the defect of polyethylene easily melting and flowing when heated. According to the cross-linking method, it is divided into three categories: chemical cross-linking, silane cross-linking, and irradiation cross-linking. Chemical cross-linking is mostly used in high-voltage power cable scenarios. During extrusion, a three-layer co-extrusion die head is used to simultaneously extrude the inner shielding layer, the cross-linked polyethylene insulation layer 200, and the outer shielding layer to ensure that the interfaces of each layer are tight and without air gaps. Medium and high voltage YJVR cables generally use chemical cross-linking catenary extrusion cross-linking process to complete the insulation coating molding.

[0063] S2. Multiple coated copper conductors 100 are fed into the cable forming machine and spirally stranded according to the specified pitch. Simultaneously, filler material is fed into the gaps between the conductors to form a filler layer 300, thereby filling the gaps between the conductors, making the overall cross-section of the cable core more rounded, and inhibiting the conductors from moving and squeezing each other. After stranding is completed, a flexible insulating layer 400 is wrapped around the outside of the cable core using a spiral overlapping wrapping machine. During the wrapping process, the tension of the tape and the overlap rate are controlled to ensure that the insulating layer is continuous and complete and does not excessively tighten the cable core. The flexible insulating layer 400 separates the cable core from the subsequent armor structure, preventing the armor metal tape from directly scratching the insulated conductors. For example, the filler layer 300 can be made of polypropylene fiber filler rope, and the flexible insulating layer 400 can be made of polyester non-woven tape.

[0064] S3. After the cable core has been processed through cabling, filling layer 300, and flexible insulating layer 400, it continues to be conveyed forward. The interlocking armored metal strip first undergoes straightening, cleaning, and grease injection pretreatment processes. The first locking part 510 and the second locking part 520 are formed by stamping or pre-bending on both sides of the metal strip. Then, the interlocking armor forming mold spirally wraps the metal strip around the outer surface of the flexible insulating layer 400. During the spiral winding process, the first locking part 510 and the second locking part 520 on adjacent sides interlock and bite each other in sequence. The first locking part on the bottom side 501 can be controlled first. Part 510 and the second locking part 520 are engaged and interlocked with each other. Then, the first locking part 510 and the second locking part 520 on the top side 502 are controlled to engage and interlock with each other. During the continuous winding process, the interlocking and locking are continuously performed. The overlap and tightness of the buckle are controlled by the radial pressure of the interlocking armor forming mold to ensure that the buckle is neither too tight to hinder cable bending nor too loose to cause loosening. After the buckling is completed, the outer diameter of the armor is adjusted by the shaping mold to achieve continuous forming of the interlocking armor layer 500. The above interlocking armor processing can be completed by using aluminum alloy armor strip.

[0065] The interlocking armor forming mold is a modular combination mold, which includes a pre-forming pressure roller group, a forming hook mold, and a sizing and shaping mold. The pre-forming pressure roller group is used to pre-bend both sides of the armor metal strip to form the first locking part 510 and the second locking part 520 respectively. The forming hook mold guides the metal strip to spirally wrap around the outer surface of the flexible isolation layer 400 and make the two locking parts interlock and bite each other. The sizing and shaping mold shapes and shapes the outer diameter of the interlocking armor layer 500 after interlocking, and suppresses the buckle from springing back and loosening. For example, an adjustable aluminum alloy interlocking armor forming mold adapted to the asymmetric buckle cross section can be used.

[0066] After the S4 interlocking armor layer 500 is formed, the cable core continues to move forward. First, it undergoes outer diameter inspection and visual inspection to check for defects such as mis-stitched, loose, or warped interlocking. Then, an outer sheath layer is extruded or wrapped around the outside of the interlocking armor layer 500. The outer sheath completely covers the interlocking armor layer 500, isolating it from external moisture, oil, and mechanical damage. After the sheath processing is completed, it goes through a cooling water bath for cooling and shaping, a spark withstand voltage test to check for sheath breakdown points, and then the outer diameter is re-measured and the meter is marked. Finally, it is pulled and wound into a finished cable reel. If necessary, the finished product can also be sampled for type testing such as bending test and compression test. For example, the outer sheath can be made of polyvinyl chloride or polyethylene.

[0067] The integrated manufacturing process, which completes conductor stranding insulation, cable filling and isolation, armor pretreatment and molding, and sheath molding and testing in the above steps, achieves precise and continuous molding of the 500-layer asymmetric rigid-flexible interlocking armor layer compared with conventional cable manufacturing processes. With dedicated pretreatment, step-by-step interlocking, and mold shaping processes, it effectively adapts to the molding requirements of differential stiffness locks, eliminates lock springback, loosening, and mis-locking defects, and ensures that each layer of the cable structure is tightly fitted, without air gaps or damage, greatly improving the molding accuracy, structural stability, and comprehensive protection performance of the finished cable.

[0068] Furthermore, step S3, cleaning and grease injection, uses a cross-linked polyethylene soft conductor insulated cable processing equipment. The cross-linked polyethylene soft conductor insulated cable processing equipment includes a cleaning device 600 and a grease injection device 700. The grease injection device 700 is located downstream of the processing path of the cleaning device 600. The grease injection device 700 includes a grease injection gun 710, a suction positioning component 720 located behind the grease injection gun 710, a one-way conveying device 730 located between the grease injection gun 710 and the suction positioning component 720, and a particle monitoring device is provided between the one-way conveying device 730 and the suction positioning component 720.

[0069] Grease can be injected into the second locking part 520 through the grease injection gun 710. The second locking part 520 is positioned during the conveying process by the suction positioning component 720. At the same time, excess grease is evenly filled and suctioned. The particle monitoring device can monitor the content of debris particles in the suctioned and recovered grease in real time. When the debris content of the suctioned and recovered grease exceeds the set threshold limit, the cleaning status of the cleaning device 600 is checked in time to ensure that the overall equipment can clean and fill grease normally and stably.

[0070] By combining the core structure of the above-mentioned equipment, which includes pre-cleaning, post-greasing suction, and online particle monitoring, compared with the existing technology of simple greasing of armored belts without online particle monitoring feedback, a closed-loop processing effect is achieved, which includes cleaning and impurity removal, precise greasing, excess grease recovery, and online early warning of impurities. This allows for real-time control of the cleanliness and greasing uniformity inside the buckle, timely troubleshooting of cleaning device 600 failures, and prevention of wear and jamming caused by residual particulate impurities inside the buckle from the production source, thus ensuring the lubrication and protection effect and molding quality of the buckle.

[0071] Specifically, the suction positioning assembly 720 includes a suction positioning disk 721, with suction holes 722 on the side wall of the suction positioning disk 721. A drive shaft 723 connected to an external power source is fixed to the side wall of the suction positioning disk 721. The drive shaft 723 is hollow to form a conveying channel. The first side of the conveying channel is connected to multiple suction holes 722, and the second side is connected to a unidirectional conveying device 730 through a rotating connector 724. The particle monitoring device is located between the rotating connector 724 and the unidirectional conveying device 730.

[0072] The aforementioned particle monitoring device can be configured to use optical detection. It has a thin transparent channel inside, a background light source on the first side, and a visual detection element on the second side. The visual detection element detects the distribution and area of ​​impurities in the transparent channel, thereby obtaining the fluctuation state of impurities in the oil.

[0073] When the suction positioning plate 721 is selected, an arc-shaped sealing block is fixed on the inner wall of the suction positioning plate 721, which can block the suction hole 722 that is deflected to the top, ensuring that the suction hole 722 at the bottom can be in a stable suction pressure range, so as to achieve effective suction. A positioning bracket is set in the middle of the arc-shaped sealing block. The positioning bracket is fixed to the fixed workpiece on the outside through the hollow interior, ensuring the relative position of the arc-shaped sealing block during the rotation of the suction positioning plate 721.

[0074] Through the aforementioned core structure of the suction positioning disc 721 with arc-shaped sealing blocks, zoned suction, and synchronous rotation positioning, compared with the existing technology of uniform suction around the entire circle and unstable pressure, it achieves a precise grease removal effect with stable negative pressure in the working area and sealing and isolation in the non-working area. It is suitable for continuous rotating conveyor belt operation, avoiding problems such as negative pressure leakage, uneven grease removal, and excessive grease residue. At the same time, it ensures the long-term structural stability of the equipment and improves the uniformity and cleanliness of grease inside the locking buckle.

[0075] Specifically, the unidirectional conveying device 730 includes a conveying housing 732, inside which a unidirectional partition plate 735 is fixed and a negative pressure generator is movably arranged. A transfer chamber 736 is formed between the negative pressure generator and the unidirectional partition plate 735, and a storage chamber 737 is formed between the unidirectional partition plate 735 and the conveying housing 732. The transfer chamber 736 and the storage chamber 737 are connected by a first conveying connector 734 with a built-in first one-way valve. The transfer chamber 736 is connected to the suction positioning assembly 720 by a second conveying connector 725 with a built-in second one-way valve.

[0076] The transfer chamber 736 is periodically controlled by a negative pressure generator to be in a negative or positive pressure state. Excess grease from the suction positioning component 720 is sucked into the transfer chamber 736 and then forced into the storage chamber 737, and finally sprayed out from the grease injection gun 710. The grease injection gun 710 includes a gun head 711 and a gun barrel 712. The gun barrel 712 extends to the bottom of the storage chamber 737 from the side away from the gun head 711. An elastic and retractable pressure storage device, such as an elastic piston or an elastic air bladder, can be set in the storage chamber 737 to maintain a relatively constant pressure state. This allows the excess grease to be stored and then continuously sprayed out from the grease injection gun 710 at a uniform speed, achieving stable grease injection.

[0077] The aforementioned negative pressure generator can be a combination of a negative pressure piston 733 and a reciprocating power rod 731. During the liposuction process, the reciprocating power rod 731 drives the negative pressure piston 733 to move up and down reciprocally. During the reciprocating movement of the negative pressure piston 733, the transfer chamber 736 is periodically alternately in positive and negative pressure states to achieve pressure control.

[0078] Through the core structure of dual-chamber unidirectional conveying, periodic positive and negative pressure switching, and constant pressure grease storage, compared with the existing open uncontrolled grease injection and extraction processing methods with large pressure fluctuations, it achieves a closed-loop oil supply effect of accurate recovery of excess grease, stable pressure, and uniform and continuous grease injection. It completely solves the problems of grease injection pressure fluctuation, grease interruption, and excessive grease overflow, ensuring that the grease inside the locking groove is evenly filled and the storage is stable, making it suitable for high-speed continuous production line operations.

[0079] Specifically, the cleaning device 600 includes an air blowing assembly 610, a suction assembly 620 is disposed between the air blowing assembly 610 and the grease injection device 700, and a one-way pumping device 630 is disposed between the air blowing assembly 610 and the suction assembly 620. A filter assembly 631 is installed inside the one-way pumping device 630. The gas continuously sucked by the suction assembly 620 is pumped unidirectionally to one side of the air blowing assembly 610 for air spraying. The air blowing assembly 610 is located at the bending position, which can continuously spray air to remove debris generated during the bending process. The suction assembly 620 is located at the non-bending position, which can continuously perform negative pressure suction inside the shape-stable locking groove, thereby minimizing the content of particulate matter in the locking groove.

[0080] By employing the core structure of blowing air at the bending position, negative pressure suction at the groove position, and unidirectional circulating pump air filtration, compared with the existing cleaning methods that rely solely on blowing or suction, this technology achieves a highly efficient cleaning effect by blowing away floating dust from bending, precisely suctioning particles embedded in the groove, and reusing gas through circulating filtration. It specifically removes metal debris and dust generated during the bending and forming of the armor belt, significantly reduces the amount of residual particles inside the buckle, improves the buckle lubrication environment from the source, and reduces subsequent micro-motion wear failures.

[0081] Finally, it should be noted that the bending process of the first and second locking parts is existing technology, and the strip body is controlled to pass through multiple extrusion rollers at different angles in conjunction with the inner support rollers to achieve extrusion molding.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cross-linked polyethylene flexible conductor insulated cable, comprising a flexible conductor and an interlocking armor layer (500) sleeved on the outside of the flexible conductor, characterized in that: The interlocking armor layer (500) includes a strip-shaped body (530), a first locking part (510) is provided on the first side of the strip-shaped body (530), and a second locking part (520) is provided on the second side. The first locking part (510) and the second locking part (520) are located on different sides of the two sides, and the stiffness of the first locking part (510) is greater than that of the second locking part (520).

2. The cross-linked polyethylene flexible conductor insulated cable according to claim 1, characterized in that, The first locking part (510) and the second locking part (520) are made of the same material, and the second locking part (520) is more prone to elastic cantilever deformation than the first locking part (510).

3. The cross-linked polyethylene flexible conductor insulated cable according to claim 2, characterized in that, The first locking part (510) includes a first connecting part (511) and a first overlapping part (512), and the second locking part (520) includes a second connecting part (521) and a second overlapping part (522). The first locking part (510) and the second locking part (520) have the same length, and the thickness of the first connecting part (511) is less than the thickness of the second connecting part (521).

4. The cross-linked polyethylene flexible conductor insulated cable according to claim 3, characterized in that, The width of the first overlapping portion (512) is greater than the width of the second overlapping portion (522).

5. The cross-linked polyethylene flexible conductor insulated cable according to any one of claims 1-4, characterized in that, The space between the first locking part (510) and the second locking part (520) is filled with lubricating grease.

6. A method for preparing cross-linked polyethylene flexible conductor insulated cable, characterized in that, The method for preparing the cross-linked polyethylene flexible conductor insulated cable according to any one of claims 1-5 comprises the following steps: S1. A copper wire conductor (100) of a predetermined diameter is stranded together, and a cross-linked polyethylene insulation layer (200) is extruded on the outside of the copper wire conductor (100). S2. Multiple coated copper conductors (100) are fed into the cabling machine and spirally twisted according to the specified pitch. At the same time as twisting, filling material is fed into the gaps between the conductors to form a filling layer (300) and a flexible isolation layer (400) is wrapped around them. S3. After the cable core is processed by cabling, filling layer (300) and flexible isolation layer (400), it is continuously conveyed forward. The interlocking armored metal strip first undergoes straightening, cleaning and grease injection pretreatment processes. The first locking part (510) and the second locking part (520) are formed on both sides of the metal strip. Then the interlocking armor forming mold spirally wraps the metal strip around the outer surface of the flexible isolation layer (400). During the spiral winding process, the first locking part (510) and the second locking part (520) on the adjacent sides are interlocked and engaged with each other in sequence. S4. After the interlocking armor layer (500) is snapped together, the outer sheath layer is processed, followed by inspection and winding.

7. The method for preparing a cross-linked polyethylene flexible conductor insulated cable according to claim 6, characterized in that, The cleaning and grease injection steps S3 utilize a cross-linked polyethylene soft conductor insulated cable processing equipment. The cross-linked polyethylene soft conductor insulated cable processing equipment includes a cleaning device (600) and a grease injection device (700). The grease injection device (700) is located downstream of the processing path of the cleaning device (600). The grease injection device (700) includes a grease injection gun (710), a suction positioning component (720) located behind the grease injection gun (710), and a one-way conveying device (730) located between the grease injection gun (710) and the suction positioning component (720). A particle monitoring device is provided between the one-way conveying device (730) and the suction positioning component (720).

8. The method for preparing a cross-linked polyethylene flexible conductor insulated cable according to claim 7, characterized in that, The suction positioning assembly (720) includes a suction positioning disk (721), the suction positioning disk (721) has suction holes (722) on its side wall, and a drive shaft (723) with an external power source is fixed to the side wall of the suction positioning disk (721). The drive shaft (723) is hollow to form a conveying channel. The first side of the conveying channel is connected to multiple suction holes (722), and the second side is connected to a one-way conveying device (730) through a rotating connector (724). The particle monitoring device is located between the rotating connector (724) and the one-way conveying device (730).

9. The method for preparing a cross-linked polyethylene flexible conductor insulated cable according to claim 7, characterized in that, The one-way conveying device (730) includes a conveying housing (732), inside which a one-way partition plate (735) is fixed and a negative pressure generator is movably arranged. A transfer chamber (736) is formed between the negative pressure generator and the one-way partition plate (735). A storage chamber (737) is formed between the one-way partition plate (735) and the conveying housing (732). The transfer chamber (736) and the storage chamber (737) are connected by a first conveying connector (734) with a built-in first one-way valve. The transfer chamber (736) is connected to the suction positioning assembly (720) through a second conveying connector (725) with a built-in second one-way valve.

10. The method for preparing a cross-linked polyethylene flexible conductor insulated cable according to claim 7, characterized in that, The cleaning device (600) includes an air blowing assembly (610), a suction assembly (620) is provided between the air blowing assembly (610) and the grease injection device (700), and a one-way pumping device (630) is provided between the air blowing assembly (610) and the suction assembly (620). A filter assembly (631) is installed in the one-way pumping device (630). The gas continuously sucked by the suction assembly (620) is pumped one-way to one side of the air blowing assembly (610) for spraying through the one-way pumping device (630).

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