High-current-carrying flame-retardant flexible cable with combined conductor structure for equipment and manufacturing method

Abstract

The present invention relates to a high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment and a manufacturing method thereof. Among them, the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment includes a cable combined conductor, an inner isolation layer, a braided layer, an outer isolation layer, and a sheath layer. The cable adopts a creative application method of a combined conductor and an insulating layer wrapped around a single conductor, which ensures that the cable can withstand the transmission of an instantaneously large impact current. Without increasing the conductor cross-section, the instantaneously safe application current-carrying capacity of the cable is increased by dozens of times, ensuring the safe application of the cable. The cable combined conductor is composed of multiple insulated wire cores stranded in a layered positive and negative manner. Each insulated wire core includes a wire core conductor and an insulating layer wrapped around the outside of the wire core conductor. Each wire core conductor is composed of multiple stranded wire bundles. The present invention can effectively reduce the eddy current effect, ensure the safe transmission and application of the cable under an instantaneously large impact current, is not easily deformed when bent, and has good structural stability.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and particularly to a high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment and a manufacturing method thereof. Background Art

[0002] With the rapid development of modern equipment, some high-power test instruments and experimental equipment require special performance cables that can instantaneously transmit ultra-large impact currents to meet the function of carrying large-power charges for instantaneous transmission. Due to reasons such as the conductor structure, insulating material, and product performance of existing cables, they do not have the above-mentioned performance, and when applied, the cables may be ablated, damaging the instruments or equipment and affecting the operation of the equipment.

[0003] The existing technical solutions have the following deficiencies:

[0004] (1) The conductor structure of the existing polyolefin material insulated cables for experiments is composed of multiple bare copper wires or tinned copper wires stranded together according to a certain rule and arrangement structure. Once a large alternating current is transmitted, a large eddy induction current (eddy induction current is also called eddy current, hereinafter referred to as eddy current for short) will be generated in the conductor. The thermal effect of the eddy current can instantly raise the temperature of the conductor to a very high level, resulting in operating failures such as the burning of the cable insulation layer or the fusing of the conductor.

[0005] (2) Conventional cable insulating materials include polyvinyl chloride, cross-linked polyethylene, halogen-free low-smoke polyolefin, and rubber, etc. Due to factors such as working temperature and material performance, they do not meet the application of the thermal effect generated by a large current impact.

[0006] (3) When the existing cables are repeatedly bent during high-temperature overload applications, it is easy for the cable insulation sheath to undergo thermal deformation. This deformation is a plastic deformation and is difficult to return to its original state after cooling. Repeated bending and stress are likely to cause the cable insulation layer and sheath layer to be damaged and cracked, leading to equipment failures and potential safety hazards.

[0007] Therefore, the present invention conceives a high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment and a manufacturing method thereof to overcome the defects of the existing technology. Summary of the Invention

[0008] The purpose of the present invention is to provide a high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment and a manufacturing method thereof, which can effectively reduce the eddy current effect, ensure the safety of the cable during the transmission application of instantaneously ultra-large impact currents, is not easily deformed when bent, and has good structural stability.

[0009] The above object of the present invention can be achieved by the following technical solutions:

[0010] The present invention provides a high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment, which includes a cable combined conductor and an inner isolation layer, a braided layer, an outer isolation layer, and a sheath layer that are sequentially arranged from the inside to the outside and wrap the outside of the cable combined conductor; the cable combined conductor is composed of multiple insulated wire cores that are stranded in a layered positive and reverse manner. Each insulated wire core includes a wire core conductor and an insulating layer that wraps the outside of the wire core conductor. Each wire core conductor is composed of multiple wire bundles that are stranded together, and each wire bundle is composed of multiple wires that are bundled together. The bundling direction of the multiple wires is the same as the stranding direction of the multiple wire bundles.

[0011] In a preferred embodiment of the present invention, the diameter of a single wire ≤ 0.08 mm.

[0012] In a preferred embodiment of the present invention, each wire core conductor is stranded in a layered manner by 7 wire bundles according to the arrangement structure of 1 + 6.

[0013] In a preferred embodiment of the present invention, the pitch diameter ratio of the wire bundle is 20 - 25; the pitch diameter ratio of the inner layer of the wire core conductor is 14 - 16, and the outer layer is 10 - 12.

[0014] In a preferred embodiment of the present invention, the insulating layer is a modified polyether ether ketone layer, and the thickness of the insulating layer is 0.1 - 0.5 mm.

[0015] In a preferred embodiment of the present invention, the insulating layer is formed by extrusion production using a semi-extrusion die. The semi-extrusion die uses multiple die sleeves, and at least one notch is provided at the discharge port of each die sleeve, and the number of notches on each die sleeve is different, so that at least one raised marking strip is formed on the outer surface of the insulated wire core.

[0016] In a preferred embodiment of the present invention, multiple insulated wire cores are stranded in a positive and reverse manner according to the arrangement structure of 1 + 6 + 12 + … + 6n, where 1 ≤ n ≤ 10 and n is a positive integer; the semi-extrusion die uses three die sleeves, and one notch, two notches, and three notches are respectively provided at the discharge ports of the three die sleeves. The outer surfaces of the multiple insulated wire cores obtained by extruding and covering the insulating layer using the extrusion die have one marking strip, two marking strips, or three marking strips, and are respectively denoted as a one-marking-strip wire core, a two-marking-strip wire core, and a three-marking-strip wire core; the multiple insulated wire cores are respectively denoted as the central layer, the first layer to the nth layer from the center to the outside. The 6n insulated wire cores included in the nth layer are arranged in the order of a one-marking-strip wire core, a two-marking-strip wire core, and a three-marking-strip wire core and are arranged in a cyclic and repetitive manner 2n times in total.

[0017] In a preferred embodiment of the present invention, the pitch diameter ratio of each layer of stranding in the cable combined conductor is 10 - 16, and the inner layer pitch is less than or equal to the outer layer pitch.

[0018] In a preferred embodiment of the present invention, both the inner isolation layer and the outer isolation layer are formed by winding polyester tapes. The thickness of the polyester tape is 0.02 - 0.05 mm, the width of the polyester tape is less than or equal to 1.5 - 2.5 times the winding diameter, and the winding overlap rate of the polyester tape is 25 - 40%.

[0019] In a preferred embodiment of the present invention, the braided layer is an aramid fiber layer, and the braiding density of the braided layer is 80 - 90%.

[0020] In a preferred embodiment of the present invention, the sheath layer is an insulating grade silicone rubber layer.

[0021] The present invention also provides a method for manufacturing a high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment, including the following steps:

[0022] Bundle multiple wires to form a wire bundle;

[0023] Strand the multiple wire bundles to form a core conductor; wherein, the bundling direction of the multiple wires is the same as the stranding direction of the multiple wire bundles;

[0024] Wrap an insulating layer around each core conductor to form an insulated wire core;

[0025] Strand the multiple insulated wire cores in a layered forward and reverse manner to form a cable combined conductor;

[0026] Wrap an inner isolation layer around the cable combined conductor;

[0027] Wrap a braided layer around the inner isolation layer;

[0028] Wrap an outer isolation layer around the braided layer;

[0029] Wrap a sheath layer around the outer isolation layer to form a high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment.

[0030] In a preferred embodiment of the present invention, the insulating layer is produced by extruding a modified polyether ether ketone material through a semi-extrusion die. After the modified polyether ether ketone material is extruded around the core conductor, it is first air-cooled, then soaked in hot water, and then soaked in cold water for step-by-step cooling in sections; wherein, the balance coefficient between the die core and the die sleeve in the semi-extrusion die is 1.00 - 1.01, and the draw ratio is 1.4 - 1.8.

[0031] In a preferred embodiment of the present invention, the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment obtained by this manufacturing method is the above-mentioned high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment.

[0032] As described above, for the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment and its manufacturing method of the present invention, the entire cable combined conductor is designed and divided into multiple insulated cores with small cross-sections. The core conductors in each insulated core are arranged in the same direction regularly and stranded in layers twice, solving the eddy current effect generated by the alternating transmission of large currents in a single conductor. The multiple insulated cores are stranded in layers multiple times in a positive and negative regular arrangement, with stronger structural stability. There are four layers in total outside the cable combined conductor. The two isolation layers mainly play the role of electrical isolation; a braided layer is arranged between the two isolation layers, making the two isolation layers softer when the cable is stretched and deformed and bent. The outer sheath layer mainly plays a flame-retardant protection role; thus, it plays a better protective role for the cable combined conductor, forming a secondary insulation protection with better flame-retardant effect. The entire flexible cable can meet the function of carrying a large amount of power charge and instantaneously transmitting an ultra-large impact current, and can be used in some high-power test instruments and test equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The following drawings are only intended to illustrate and explain the present invention schematically and do not limit the scope of the present invention.

[0034] Wherein:

[0035] Figure 1 : is a cross-sectional schematic view of the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment provided by the present invention.

[0036] Figure 2 : is a cross-sectional schematic view of one of the core conductors provided by the present invention.

[0037] Description of the reference numerals in the drawings:

[0038] 1. Cable combined conductor; 11. Core conductor; 12. Insulation layer;

[0039] 2. Inner isolation layer; 3. Braided layer; 4. Outer isolation layer; 5. Sheath layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] In order to have a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0041] As shown in Figure 1 and Figure 2As shown in the figure, this embodiment provides a high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment, which includes a cable combined conductor 1 and an inner isolation layer 2, a braided layer 3, an outer isolation layer 4, and a sheath layer 5 that are sequentially arranged outside the cable combined conductor 1 from inside to outside; the cable combined conductor 1 is composed of multiple insulated wire cores that are stranded in a positive and negative manner in layers. Each insulated wire core includes a wire core conductor 11 and an insulating layer 12 wrapped outside the wire core conductor 11. Each wire core conductor 11 is composed of multiple wire bundles stranded together, and each wire bundle is composed of multiple wires. The bundling direction of the multiple wires is the same as the stranding direction of the multiple wire bundles.

[0042] Thus, for the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment in this embodiment, the entire cable combined conductor 1 is designed and divided into multiple insulated wire cores with small cross-sections. The wire core conductors 11 in each insulated wire core are stranded in a regular arrangement in the same direction in layers and then stranded twice, solving the eddy current effect generated by the alternating transmission of large currents in a single conductor. The multiple insulated wire cores are stranded in a positive and negative regular arrangement in layers and stranded multiple times, and the structural stability is stronger. There are a total of four layers outside the cable combined conductor 1. The two isolation layers mainly play the role of electrical isolation; a braided layer 3 is arranged between the two isolation layers, making it softer when the two isolation layers are deformed and bent during the stretching deformation of the cable; the sheath layer 5 mainly plays a flame-retardant protection role; thus, it plays a better protection role for the cable combined conductor 1, forming a secondary insulation protection, and the flame-retardant effect is better. The entire flexible cable can meet the function of carrying a large-power charge and instantaneously transmitting an ultra-large impact current (i.e., high current-carrying), and can be used in some high-power test instruments and test equipment.

[0043] In a specific implementation manner, the diameter of a single wire ≤ 0.08 mm. The wire can be, for example, a copper wire. Since the diameter of a single wire is relatively thin, stranding multiple thin wires together can effectively reduce the eddy current generated by the change in the conductor current.

[0044] Refer to Figure 2 , each wire core conductor 11 is stranded in layers according to the arrangement structure of 1 + 6 by 7 wire bundles, which can not only meet the requirements of cross-sectional area and resistance but also simplify the process.

[0045] First, multiple wire bundles are bundled into a strand, and then they are stranded in the same direction according to the 1 + 6 arrangement structure into a wire core conductor 11 with a small cross-section. Since they are stranded after being bundled into a strand, the original bundled part is restricted in a fixed area (refer to Figure 2), it is not prone to large displacement during bending, which may cause the stranded wire to deform; the pitch diameter ratio of the strand (i.e., the pitch diameter ratio of the wire bundle) is controlled between 20 - 25, the pitch diameter ratio of the stranded wire (the pitch diameter ratio of the core conductor 11) is controlled between 14 - 16 for the inner layer and between 10 - 12 for the outer layer. Due to the secondary stranding with the same direction for the bunching direction and the strand stranding direction, the bunching pitch is appropriately reduced during the secondary stranding, resembling a primary bunching structure. Therefore, the stranded core conductor 11 with a small cross-section visually appears as a single conductor. Placed on a sheave with a diameter 10 times that of the conductor, after 3000 flexing tests, no single wire protrudes from the conductor and no wire breaks are exposed. This solves the problem of core breakage in the conductor, as well as the problem that the insulation layer 12 may be damaged due to the breakage or protrusion of the conductor during bending, which affects the product performance.

[0046] The multi-strand annealed bunched soft wire is stranded into the core conductor 11 with a small cross-section of the cable according to the arrangement structure of 1 strand + 6 strands. In a specific embodiment, the core conductor 11 with 91 cores is stranded into a cable combined conductor 1 of 95mm 2 and the cable combined conductor 1 of 95mm 2 requires that the DC resistance at 20 °C is not greater than 0.206 Ω / km. When the core conductor 11 with a small cross-section is segmented, a 5% production process stretching allowance is reserved, and the DC resistance of each core should be controlled to not be greater than 17.8 Ω / km. The calculation uses single wires with a diameter not less than 0.07 mm, with no less than 36 wires per strand, stranded together. The strand and the stranded wire are produced by co-directional stranding, which can reduce the outer diameter of the conductor and the core, and the core is softer.

[0047] The above-mentioned insulation layer 12 is preferably made of a modified polyether ether ketone layer.

[0048] During the production of the insulation layer 12, it is extruded using a semi-extrusion die. The balance coefficient K value between the die core and the die sleeve is controlled between 1.00 - 1.01, and the draw ratio S value is controlled between 1.4 - 1.8. The extrusion is tight and easy to peel off, which not only ensures the production speed but also ensures the appearance quality of the extruded insulation layer 12.

[0049] During the extrusion coating process of the modified polyether ether ketone insulation layer, due to the small core diameter and high production line speed, it is difficult to print on the surface. Laser marking also affects the production efficiency. Also, due to the special material properties and high price, if color separation production is carried out, it will increase the types and quantities of raw material colors in storage, significantly increasing the production and operation costs. In this embodiment, the insulation layer 12 is formed by extrusion using a semi-extrusion die. The semi-extrusion die uses multiple die sleeves, and at least one notch is provided at the discharge port of each die sleeve, and the number of notches on each die sleeve is different, so that at least one raised marking strip is formed on the outer surface of the insulated core.

[0050] The length direction of the above-mentioned notch is arranged along the axial direction at the discharge port. When there are multiple notches, the multiple notches are evenly spaced circumferentially. During extrusion coating, due to the existence of this notch, a bulge can be formed on the obtained insulating layer 12 at this position, and then a raised marking strip is formed on the outer surface of the produced insulated wire core. The length direction of this marking strip extends along the axial direction of the insulated wire core; the specific number of die sleeves is determined according to needs. For example, in this embodiment, a total of three die sleeves are used. One notch, two notches, and three notches are respectively provided at the discharge ports of the three die sleeves. The outer surfaces of the produced insulated wire cores respectively have one marking strip, two marking strips, and three marking strips to meet the use requirements and simplify the process. In this way, during the extrusion coating process, three die sleeves are used. A notch is filed with a file at the discharge port of one die sleeve, two notches are filed on another die sleeve, and three notches are filed on the remaining die sleeve. When extruding, a raised marking strip is formed at the notch of the die sleeve. Without changing the material color and not printing surface markings, the insulated wire cores can be identified and distinguished only by the number of raised marking lines on the surface of the insulated wire core.

[0051] The insulating layer 12 with high temperature resistance, anti-eddy current, and resistance to large current impact is formed by heating, plasticizing, and extruding a modified polyetheretherketone insulating material tightly coated on the small cross-section wire core conductor 11. The thickness of the insulating layer 12 is controlled within the range of 0.10 - 0.50 mm. For a conductor cross-section of about 1 mm 2 or so, the thickness of the insulating layer 12 is preferably designed to be about 0.20 - 0.30 mm. If the insulating layer 12 is too thin, the process is difficult to control and the spark test is prone to breakdown. If the insulating layer 12 is too thick, the outer diameter of the product is too large, affecting the bending radius of the product. During the high-temperature extrusion and plasticizing extrusion of the insulating layer 12 using a high-temperature extruder, air pre-cooling is first adopted, so the production line speed should not be too fast. Then, hot water immersion is carried out, and then cold water immersion is used for step-by-step cooling in sections to prevent the insulating layer 12 of the modified polyetheretherketone (PEEK) material from having a fast cooling rate and generating brittle stress, which may cause the insulating layer 12 to crack and not meet the product performance requirements.

[0052] The insulating layer 12 uses a thermoplastic flame-retardant polymer material, modified polyetheretherketone (PEEK), which has high mechanical strength, high temperature resistance, corrosion resistance, hydrolysis resistance, impact resistance, fatigue resistance, and good electrical insulation performance as the extrusion coating material. The heat distortion temperature of the modified polyetheretherketone insulating material is high (up to 316 °C). When the transmitted current is extremely large, the cable conductor can continue to work stably at a temperature as high as 300 °C, solving the potential hazard that the insulating layer 12 is prone to ablation due to high-temperature deformation. The product in this embodiment will not be ablated and damaged due to sudden changes in the instantaneous current-carrying capacity, and can ensure the normal operation of the equipment.

[0053] In an alternative embodiment, the insulating layer 12 can also use materials such as silicone rubber and thermoplastic polyimide (TPI). The extrusion high-temperature resistance performance is generally close, and the high-temperature resistance performance of polyimide is relatively excellent.

[0054] In actual application, a special wire stripper is used to strip the polyether ether ketone insulation layer 12 at the cable end by about 1 to 2 cm, the terminal is crimped in groups, and then connected to a wiring board to form a combined conductor 1 of one-phase cable. The current is transmitted for a short time not less than 1000 A within 30 s, and the instantaneous transmission current of the cable is not less than 5000 A, solving the eddy current effect generated by the transmission of ultra-large alternating current and the thermal deformation problem of the cable. The cable has a high working temperature, a large instantaneous current-carrying capacity, and a strong impact resistance, which can meet the functions of instantaneous power transmission and grounding conduction protection of high-power test instruments and test equipment. It also has performance requirements such as flame retardancy, abrasion resistance, corrosion resistance, and flexible bending.

[0055] Furthermore, multiple insulated wire cores are stranded in a forward and reverse manner according to the arrangement structure of 1 + 6 + 12 + … + 6n, where 1 ≤ n ≤ 10 and n is a positive integer. The outer surfaces of the multiple insulated wire cores obtained by extrusion and sheathing production using the above extrusion die with three die sleeves have one, two, or three marking strips, which are respectively denoted as a wire core with one marking strip, a wire core with two marking strips, and a wire core with three marking strips; the layers of the multiple insulated wire cores from the center to the outside are respectively denoted as the center layer, the first layer to the nth layer, and the 6n insulated wire cores included in the nth layer are arranged in the order of a wire core with one identification strip, a wire core with two identification strips, and a wire core with three identification strips and are arranged in a total of 2n cycles.

[0056] Specifically, in the arrangement of the insulated wire cores, the center layer is any insulated wire core with an identification strip. The 6 insulated wire cores in the first layer are arranged as a wire core with one identification strip, a wire core with two identification strips, and a wire core with three identification strips, and then arranged in a cycle once (that is, arranged in a total of 2 cycles); the 12 insulated wire cores in the second layer are arranged as a wire core with one identification strip, a wire core with two identification strips, and a wire core with three identification strips, and are arranged in a total of 4 cycles; the 18 wire cores in the third layer are arranged as a wire core with one identification strip, a wire core with two identification strips, and a wire core with three identification strips, and are arranged in a total of 6 cycles; and so on... In product application, the wire core with one marking strip, the wire core with two marking strips, and the wire core with three marking strips are separately connected to the corresponding grouped wire positions; when separately combined and connected to different positions, the current can be evenly distributed to each small wire core for transmission. The pitch diameter ratio of each layer of stranding in the combined conductor 1 of the cable is 10 - 16, the stranding is tight, and the inner layer pitch is not greater than the outer layer pitch. The smaller pitch diameter ratio of the layered stranding and the inner and outer layer pitches are strictly controlled, ensuring the flexible bending performance of the product and the function of recovering from bending deformation. The stranding structure has better stability during multiple bending uses.

[0057] Furthermore, both the inner isolation layer 2 and the outer isolation layer 4 are formed by winding a polyester tape. The thickness of the polyester tape is 0.02 - 0.05 mm, the width of the polyester tape is less than or equal to 1.5 - 2.5 times the winding diameter, and the winding overlap rate of the polyester tape is 25 - 40%.

[0058] The inner isolation layer 2 and the outer isolation layer 4 are formed by winding a polyester tape with a specific thinner width. For example, in this embodiment, a polyester tape with a thickness of 0.03 mm and a width of 40 mm is used for winding isolation with an overlap rate of about 33%. This not only increases the winding bending displacement sliding performance and can quickly return to its original state after being straightened, but also has electrical isolation and insulation performance, ensuring the soft performance of the product.

[0059] The braided layer 3 is an aramid fiber layer, and the braiding density of the braided layer 3 is 80 - 90%.

[0060] An aramid fiber braided layer 3 is arranged between the inner isolation layer 2 and the outer isolation layer 4. Aramid fibers are used for braiding protection, and the braiding density is, for example, about 85%. The high - density braiding increases the protection function against tensile application deformation.

[0061] The sheath layer 5 is an insulating grade silicone rubber layer.

[0062] An insulating grade silicone rubber cable sheath material with high temperature resistance is used, and it is extruded and tightly coated outside the outer isolation layer 4 to form a bending - resistant, wear - resistant, corrosion - resistant, and soft flame - retardant sheath layer 5. After molding, it is baked and vulcanized for a set time in a step - temperature tank below 200 °C and then introduced into a water tank for cooling. The extruded and vulcanized sheath layer 5 is easily peeled off without sticking to the outer isolation layer 4. The cable has a high working temperature, a large instantaneous current - carrying capacity, and strong impact resistance, and can meet the requirements of instantaneous power transmission and grounding conduction protection for high - power test instruments and test equipment, as well as performance requirements such as flame - retardancy, wear - resistance, corrosion - resistance, and soft bending.

[0063] By using a polyester tape with a thickness in the range of 0.02 - 0.05 mm and a width not exceeding 1.5 - 2.5 times the winding diameter for overlapping winding isolation outside the cable combined conductor 1, the winding overlap rate should be controlled within the range of 25% - 40%; then aramid fibers are used for braiding outside, and the braiding density is controlled between 80% - 90%; then a polyester tape is wound outside the braided layer 3 for effective isolation, and finally a flame - retardant sheath layer 5 is coated, effectively protecting the cable combined conductor 1.

[0064] Furthermore, this embodiment also provides a manufacturing method for a high - current - carrying flame - retardant flexible cable for equipment, including:

[0065] Stranding multiple wires to form a wire bundle;

[0066] Twisting multiple wire bundles to form a core conductor 11; among them, the stranding direction of multiple wires is the same as the twisting direction of multiple wire bundles.

[0067] Wrapping an insulating layer 12 outside each core conductor 11 to form an insulated wire core;

[0068] Stratify and twist multiple insulated cores in positive and reverse directions to form a cable combined conductor 1;

[0069] Wrap an inner isolation layer 2 outside the cable combined conductor 1;

[0070] Wrap a braided layer 3 outside the inner isolation layer 2;

[0071] Wrap an outer isolation layer 4 outside the braided layer 3;

[0072] Wrap a sheath layer 5 outside the outer isolation layer 4 to form a high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment use.

[0073] Furthermore, the insulating layer 12 is produced by extruding a modified polyether ether ketone material through a semi-extrusion die. After the modified polyether ether ketone material is extruded around the core conductor 11, it is first pre-cooled with air, then soaked in hot water, and then soaked in cold water for step-by-step cooling in segments. Among them, the balance coefficient of the die core and the die sleeve in the semi-extrusion die is 1.00 - 1.01, and the draw ratio is 1.4 - 1.8.

[0074] The high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment use obtained by this manufacturing method is the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment shown in the above Figure 1 and Figure 2 The specific principle and effect have been described in detail above and will not be elaborated here.

[0075] In summary, the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment and the manufacturing method in this embodiment belong to the cables and manufacturing methods for modern high-power test instruments and test equipment. When the product is applied, the one-label strip core, two-label strip cores, and three-label strip cores are separately connected to the corresponding grouped wire positions; when separately combined and connected to different positions, the current can be evenly distributed to each small wire core for transmission. The entire flexible cable adopts a creative application method of a combined conductor and a high-temperature-resistant material insulating layer wrapped outside a single conductor, ensuring that the cable can withstand an instantaneous ultra-large impact current (the cable conductor cross-section can withstand a current exceeding 10 A within 1 mm 2 ). Without increasing the conductor cross-section, the instantaneous safe application current-carrying capacity of the cable is increased by dozens of times. The current transmitted within 30 s is not less than 1000 A, and the instantaneous transmitted current of the cable is not less than 5000 A, solving the eddy current effect generated by the transmission of ultra-large alternating current and the thermal deformation problem of the cable. Specifically, it can meet the technical scope of ultra-large current instantaneous transmission applications, provide transmission performance for current ultra-large power electromagnetic conversion, and meet the energy-saving protection requirements for the power transmission wiring of large-power equipment operation. It has the following advantages:

[0076] (1) The cable conductor first bundles multiple copper wires and then strangles them in the same direction according to the 1+6 arrangement structure. When strangling in the same direction, some pitch of the stranded wire strands will be removed, resembling a primary bundling structure. The product has a small outer diameter, is more flexible, and has high production efficiency. Multiple core conductors 11 are then strangled in the forward and reverse directions according to the arrangement structure of 1+6+12+18+24+30+… The stranded wire structure has better stability when used with multiple bends. The entire cable combined conductor 1 is designed by strangling multiple small-section core conductors 11 with an insulating layer 12 together. When in use, the insulating layer 12 is stripped off and then pressed together with a terminal, solving the eddy current effect generated by the large-current alternating transmission of a single conductor formed by strangling multiple metal wires;

[0077] (2) The insulating layer 12 uses the thermoplastic flame-retardant polymer material polyetheretherketone with high mechanical strength, high temperature resistance, corrosion resistance, hydrolysis resistance, impact resistance, fatigue resistance, and good electrical insulation performance. The heat distortion temperature of this material can reach above 316°C. It solves the problem of high-temperature deformation of the insulating layer 12 when the temperature of the ultra-high-current cable conductor is as high as 300°C. The product of the present invention will not be ablated and damaged due to the sudden change of the instantaneous current-carrying capacity, and can ensure the normal operation of the equipment.

[0078] (3) The core conductor 11 meets the requirements of the standard strangling test. There is no single wire protruding and no wire breakage exposed in the core conductor 11. It solves the problem of core breakage of the conductor, as well as the problem that the breakage or protrusion of the conductor during bending affects the performance of the product due to damage to the insulating layer 12. The extrusion design parameters are mainly controlled. The extrusion is tight and easy to peel off. The thickness of the insulating layer 12 is controlled within a relatively thin range, ensuring that the outer diameter of the cable combined conductor 1 will not be too large; the small pitch ratio strangling and the overlapping winding of the polyester tape solve the performance requirements of the cable for flexibility during bending movement and restoration to its original shape after deformation. High-density braiding with aramid fibers increases the protection function against application deformation. The flame-retardant flexible cable made of a modified polyetheretherketone insulating silicone rubber material sheath and a special process structure has a high operating temperature and strong impact resistance, and can meet the performance requirements such as instantaneous power transmission of high-power equipment and grounding conduction protection.

[0079] The above is only the schematic specific implementation manner of the present invention, and is not used to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment, characterized in that, it includes a cable combined conductor and an inner isolation layer, a braided layer, an outer isolation layer, and a sheath layer that are sequentially arranged outside the cable combined conductor from inside to outside; the cable combined conductor is composed of multiple insulated cores that are stranded in a layered positive and reverse manner. Each insulated core includes a core conductor and an insulating layer wrapped outside the core conductor. Each core conductor is composed of multiple wire bundles stranded together, and each wire bundle is composed of multiple wires bundled together. The bundling direction of the multiple wires is the same as the stranding direction of the multiple wire bundles; the insulating layer is a modified polyether ether ketone layer, and the thickness of the insulating layer is 0.1 - 0.5 mm; the insulating layer is produced by extruding the modified polyether ether ketone material through a semi-extrusion die. After the modified polyether ether ketone material is extruded around the core conductor, it is first pre-cooled with air, then soaked in hot water, and then soaked in cold water for step-by-step cooling in segments; multiple insulated cores are stranded in a layered positive and reverse manner according to the arrangement structure of 1 + 6 + 12 + … + 6n, where 1 ≤ n ≤ 10 and n is a positive integer; the insulating layer is produced by extrusion through a semi-extrusion die. The semi-extrusion die uses three die sleeves, and there is one notch, two notches, and three notches respectively at the discharge ports of the three die sleeves. The outer surfaces of the multiple insulated cores obtained by extruding and covering the insulating layer with the extrusion die have one marking strip, two marking strips, or three marking strips, and are respectively denoted as a one-marking-strip core, a two-marking-strip core, and a three-marking-strip core; the layers of the multiple insulated cores from the center to the outside are respectively denoted as the center layer, the first layer to the nth layer. The 6n insulated cores included in the nth layer are arranged in the order of a one-marking-strip core, a two-marking-strip core, and a three-marking-strip core and are arranged in a cyclic and repeated manner 2n times in total; the one-marking-strip core, the two-marking-strip core, and the three-marking-strip core can be respectively connected to the corresponding grouped wire positions to evenly distribute the current to each core for transmission.

2. The high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment according to claim 1, characterized in that, the diameter of a single wire ≤ 0.08 mm.

3. The high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment according to claim 1, characterized in that, each core conductor is stranded in a layered manner according to the arrangement structure of 1 + 6 by 7 wire bundles.

4. The high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment according to claim 3, characterized in that, the pitch diameter ratio of the wire bundle is 20 - 25; the pitch diameter ratio of the inner layer of the core conductor is 14 - 16, and the outer layer is 10 - 12.

5. The high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment according to claim 1, characterized in that, the pitch diameter ratio of each layer of stranding in the cable combined conductor is 10 - 16, and the inner layer pitch is less than or equal to the outer layer pitch.

6. The high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment according to claim 1, characterized in that, Both the inner isolation layer and the outer isolation layer are formed by winding polyester tapes. The thickness of the polyester tape is 0.02 - 0.05 mm. The width of the polyester tape is less than or equal to 1.5 - 2.5 times the winding diameter. The winding overlap rate of the polyester tape is 25 - 40%.

7. The high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment as claimed in claim 1, characterized in that, the braided layer is an aramid fiber layer, and the braiding density of the braided layer is 80 - 90%.

8. The high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment as claimed in claim 1, characterized in that, the sheath layer is an insulating-grade silicone rubber layer.

9. A method for manufacturing the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment as claimed in any one of claims 1 - 8, characterized in that, it comprises the following steps: Stranding multiple wires to form a wire bundle; Twisting multiple strands of the wire bundle to form a core conductor; wherein, the stranding direction of the multiple wires is the same as the twisting direction of the multiple strands of the wire bundle; Wrapping an insulating layer around each core conductor to form an insulated wire core; Stranding multiple insulated wire cores in a layered forward and reverse manner to form a cable combined conductor; Wrapping an inner isolation layer around the cable combined conductor; Wrapping a braided layer around the inner isolation layer; Wrapping an outer isolation layer around the braided layer; Wrapping a sheath layer around the outer isolation layer to form the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment.

10. The method for manufacturing the high-current-carrying flame-retardant flexible cable with a combined conductor structure for equipment as claimed in claim 9, characterized in that, the insulating layer is produced by extruding a modified polyether ether ketone material through a semi-extrusion die. After the modified polyether ether ketone material is extruded and wrapped around the core conductor, it is first cooled by air pre-cooling, then soaked in hot water, and then soaked in cold water in a segmented and step-by-step manner for cooling.

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