Super-flexible cable for humanoid robot and preparation method of super-flexible cable

Abstract

The invention provides a super-flexible cable for a humanoid robot and a preparation method thereof, the super-flexible cable for the humanoid robot comprises a core body, an insulating layer and a sheath, the core body comprises copper foil wires and an aramid fiber column, and the plurality of copper foil wires are spirally twisted by taking the aramid fiber column as a center; the insulating layer comprises modified aramid fibers, and the modified aramid fibers are obtained by processing aramid fibers with a LiCl-polyvinylpyrrolidone solution and grafting the aramid fibers with a toluene solution of trimethoxysilane / 1, 6-hexamethylene diisocyanate. The cable provided by the invention has excellent flexibility, and is suitable for various complex and narrow installation spaces and frequent bending application scenes; the addition of the modified aramid fiber and the optimized cabling structure significantly improve the tensile strength and bending fatigue resistance of the cable, and prolong the service life.

Description

Technical Field

[0001] The present application relates to the technical field of wires and cables, and in particular to an ultra-flexible cable for a humanoid robot and a preparation method thereof. Background Art

[0002] Robot cables must use annealed copper wire and may contain tensile elements. The insulation thickness must reach at least 90% of the nominal value. Mechanical life tests, such as 5 million drag chain tests and 1 million 90-degree bend tests, ensure the cables' reliability in the highly dynamic operating conditions of industrial robots.

[0003] While pursuing electrical conductivity, traditional cables often neglect flexibility and resistance to bending fatigue, which is particularly limiting in applications requiring frequent movement or bending. While existing flexible cables have seen some improvements, most utilize a single material or structural modification, making it difficult to achieve both excellent flexibility and long-term fatigue resistance while maintaining high conductivity. Therefore, developing a new type of cable that meets the requirements of high strength and high conductivity while also possessing ultra-flexibility and excellent fatigue resistance is crucial. Summary of the Invention

[0004] The present application is made in view of the above problems, and its purpose is to provide an ultra-flexible cable for a humanoid robot and a preparation method thereof.

[0005] Specifically, the first aspect of the present application provides an ultra-flexible cable for a humanoid robot, comprising a core, an insulating layer and a sheath, wherein the core comprises copper foil wire and an aramid fiber column, and a plurality of the copper foil wires are spirally twisted with the aramid fiber column as the center; the raw materials for preparing the insulating layer include styrene-butadiene rubber, high styrene and modified aramid fiber, and the modified aramid fiber is obtained by treating aramid fiber with a LiCl-polyvinyl pyrrolidone solution and then grafting aramid fiber with a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate.

[0006] Furthermore, the mass fraction of LiCl in the LiCl-polyvinyl pyrrolidone solution is 35-42%.

[0007] Furthermore, the insulating layer comprises the following raw materials in parts by weight: 25-35 parts of styrene-butadiene rubber, 15-30 parts of high styrene, 16-22 parts of stearic acid, 5-8 parts of modified aramid fiber, 3-5 parts of white carbon black, 3-8 parts of accelerator, 2-7 parts of zinc oxide, 3-6 parts of antioxidant, 1-5 parts of paraffin, and 1-5 parts of aromatic oil.

[0008] Furthermore, the aramid fiber column comprises a plurality of aramid fibers with a density of more than 1000d twisted together, and a protective coating is provided on the surface of the aramid fiber column.

[0009] Furthermore, the copper foil wire has a thickness of 5-15 μm, a pitch to copper foil width ratio of 1:1-1:3, and a winding angle of 40-50°.

[0010] Furthermore, the core is arranged in the cabling structure layer, the sheath is arranged outside the cabling structure, and the middle of the cabling structure is filled with a plurality of aramid fiber columns.

[0011] Furthermore, the sheath includes an inner sheath, a shielding layer and an outer sheath, and the shielding layer includes a conductive yarn woven from a blend of copper fiber and aramid fiber, wherein the mass fraction of copper fiber is 55-60 parts and the mass fraction of aramid fiber is 40-45 parts.

[0012] Furthermore, the inner sheath and the outer sheath include the following raw materials in parts by weight: 80-100 parts of styrene-butadiene rubber, 10-15 parts of nano-silica, 20-30 parts of polyvinyl chloride, 1-5 parts of calcium carbonate, 1-2 parts of 2,6-di-tert-butyl-4-methylphenol, 0.5-1 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], 0.5-1 parts of benzotriazole ultraviolet absorber, 3-5 parts of silicone hydrophobic agent, 5-8 parts of expanded graphite, 0.5-1 parts of silane coupling agent, and 1-5 parts of polyethylene wax.

[0013] Furthermore, the surface of the inner sheath is coated with a flame retardant coating, and the outer surface of the outer sheath is provided with a wear-resistant coating.

[0014] A second aspect of the present application provides a method for preparing the ultra-flexible cable for a humanoid robot, comprising the following steps: S1: Use a coating machine to spirally wrap the copper foil around the aramid fiber column, and then twist several copper foils in layers to form a conductor; S2: Weighing styrene-butadiene rubber, high styrene, stearic acid, aramid fiber, white carbon black, accelerator, zinc oxide, antioxidant, paraffin wax, and aromatic oil in proportion, mixing and kneading a mixture, and extruding the mixture into an insulating layer, which is then coated on the conductor to form an insulating core; S3: twisting a plurality of the insulating cores to form a cable core wire; S4: Styrene-butadiene rubber, nano-silica, polyvinyl chloride, calcium carbonate, 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], benzotriazole ultraviolet absorber, silicone hydrophobic agent, expanded graphite, silane coupling agent, and polyethylene wax are weighed in proportion to prepare an inner sheath; S5: Wrap the inner sheath around the outer layer of the cable core wire, and then wrap the shielding layer and the outer sheath in sequence to obtain an ultra-flexible cable for a humanoid robot.

[0015] The present invention has the following beneficial effects: (1) The core of the ultra-flexible cable for humanoid robots of the present invention is formed by spirally twisting a number of the copper foil wires with an aramid fiber column as the center. The aramid fiber itself has the characteristics of high modulus and high strength. After being embedded in the copper foil wire, the tensile strength of the conductor is significantly improved. This structure enables the conductor to maintain its integrity when subjected to external tension. It is particularly suitable for scenes that require frequent movement or bending (such as robot cables, drag chain cables, etc.); and the spiral structure of the copper foil wire combined with the flexibility of the aramid fiber enables the copper foil wire to be repeatedly bent in a complex wiring environment without being easily broken or deformed. The flexibility is better than that of traditional pure copper wire, and it is suitable for fields with high flexibility requirements such as smart wearable devices and medical devices.

[0016] (2) The modified aramid fiber in the insulating layer of the present invention is treated with a LiCl-polyvinyl pyrrolidone solution, wherein LiCl can be loaded into the aramid fiber to destroy the hydrogen bonds in the aramid fiber molecules, thereby increasing the nitrogen content and the number of -NH groups on the surface of the aramid fiber, etching the fiber surface to form grooves, and increasing the surface roughness, thereby improving the bonding performance of the aramid fiber with styrene-butadiene rubber and high styrene; at the same time, the arrangement of the aramid molecular chain is adjusted through ionic action, so that the tensile strength and shear strength of the modified aramid fiber are improved. Polyvinyl pyrrolidone can improve the dispersibility of LiCl, disperse LiCl more evenly in the solution, reduce the agglomeration of the aramid fiber, and uniformly increase the strength of the aramid fiber; the treated aramid fiber is also grafted with a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate. The grafted aramid fiber is more tightly bonded to other materials in the insulating layer, effectively improving the overall flexibility, durability and anti-aging performance of the cable, ensuring that it can still work stably in extreme environments, extending its service life, and meeting high reliability requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0018] Figure 1 This is a schematic structural diagram of the ultra-flexible cable for a humanoid robot according to the present invention.

[0019] Description of Figure Numbers: 1-Copper foil; 2-Aramid fiber column; 3-Insulation layer; 4-Inner sheath; 5-Shielding layer; 6-Outer sheath.

[0020] The purpose, features and advantages of this drawing will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative work are within the scope of protection of this application.

[0022] Obviously, the following descriptions are merely some examples or embodiments of the present application. Those skilled in the art can apply the present application to other similar scenarios without inventive effort. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in the present application, changes in design, manufacturing, or production based on the technical content disclosed in the present application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in the present application.

[0023] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0024] An embodiment of the first aspect of the present application provides an ultra-flexible cable for a humanoid robot, comprising a core, an insulating layer and a sheath, wherein the core comprises copper foil wire and an aramid fiber column, and a plurality of the copper foil wires are spirally twisted with the aramid fiber column as the center; the raw material for preparing the insulating layer comprises modified aramid fiber, and the modified aramid fiber is obtained by treating aramid fiber with a LiCl-polyvinyl pyrrolidone solution and then grafting aramid fiber with a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate.

[0025] The ultra-flexible cable core for humanoid robots of the present invention is constructed from several copper foil strands twisted helically around an aramid fiber core. The aramid fiber itself possesses high modulus and strength, and the copper foil significantly enhances the conductor's tensile strength when embedded in the strands. This structure allows the conductor to maintain integrity even when subjected to external forces, making it particularly suitable for applications requiring frequent movement or bending, such as robotic cables and drag chain cables. The copper foil's helical structure, combined with the aramid fiber's flexibility, allows the cable to be repeatedly bent in complex wiring environments without breaking or deforming. This superior flexibility to traditional pure copper wire makes it suitable for applications requiring high flexibility, such as smart wearable devices and medical equipment.

[0026] The modified aramid fiber in the insulating layer of the present invention is treated with a LiCl-polyvinyl pyrrolidone solution, wherein LiCl can be loaded into the aramid fiber to disrupt the hydrogen bonds in the aramid fiber molecules, thereby increasing the nitrogen content and the number of -NH groups on the aramid fiber surface. Grooves are etched on the fiber surface, increasing the surface roughness, thereby improving the bonding performance of the aramid fiber with styrene-butadiene rubber, high styrene, and other insulating materials. At the same time, the arrangement of the aramid molecular chains is adjusted through ionic interaction, thereby improving the tensile strength and shear strength of the modified aramid fiber. Polyvinyl pyrrolidone can improve the dispersibility of LiCl, dispersing LiCl more evenly in the solution, reducing the agglomeration of the aramid fiber, and uniformly increasing the strength of the aramid fiber. At the same time, polyvinyl pyrrolidone has certain toughening properties, further improving the bendability of the aramid fiber.

[0027] The present invention also uses a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate to graft aramid fibers. The grafted aramid fibers are more tightly bonded to other materials in the insulation layer, effectively improving the overall flexibility, durability, and aging resistance of the cable, ensuring that it can still work stably in extreme environments, extending its service life, and meeting high reliability requirements.

[0028] In an embodiment of the present invention, the mass fraction of LiCl in the LiCl-polyvinyl pyrrolidone solution is 35-42%. Preferably, the mass fraction of LiCl is any one of 35%, 37%, 39%, 40%, 42%, etc. In addition, the LiCl-polyvinyl pyrrolidone solution ensures the uniform dispersion of LiCl and the uniform reinforcement of the aramid fiber, further optimizes the comprehensive performance of the insulation layer, and improves the stability and reliability of the cable in complex environments such as high temperature and high humidity. By precisely controlling the solution ratio, the surface treatment effect of the modified aramid fiber is significantly improved, the interfacial bonding force with the insulation layer material is enhanced, and the cable is ensured to maintain excellent electrical performance and mechanical strength during long-term use, effectively coping with various harsh working conditions, and providing a reliable solution for high-end application fields.

[0029] The preparation method of the modified aramid fiber is: LiCl and polyvinyl pyrrolidone are weighed in proportion and dissolved in 3-5 times the amount of ethanol solution, and heated until completely dissolved to obtain a uniform and transparent LiCl-polyvinyl pyrrolidone solution.

[0030] Anhydrous toluene was added to the reaction vessel, and trimethoxysilane was slowly added dropwise under stirring. The dropping speed was controlled to avoid local overheating. The temperature was maintained at 20-25°C. The mixture was stirred for 20-40 minutes until completely dissolved. 1,6-hexamethylene diisocyanate was slowly added through a constant pressure dropping funnel. The mass ratio of trimethoxysilane to 1,6-hexamethylene diisocyanate was 3:2. The amount of anhydrous toluene was 5 times the mass of trimethoxysilane and 1,6-hexamethylene diisocyanate. The system temperature was maintained at 20-25°C. After the addition was completed, stirring was continued for 1-2 hours to ensure uniform mixing to obtain a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate.

[0031] The aramid fiber is immersed in a LiCl-polyvinyl pyrrolidone solution and stirred at a constant temperature for 2-4 hours to ensure full infiltration of the aramid fiber and effective attachment of the LiCl-polyvinyl pyrrolidone to the fiber surface, maintaining surface moisture. The aramid fiber is then immersed in a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate and subjected to ultrasonic treatment for 20-30 minutes. The fiber is then placed in an oven at 90-100°C for 1-1.5 hours, followed by an oven at 130-150°C for 3-5 hours to allow the toluene to evaporate completely. The fiber is then removed from the oven, immersed in deionized water at 100°C for 1-2 hours, and dried to obtain the modified aramid fiber. The modified aramid fiber prepared by this method exhibits moderate surface roughness, a stable structure, and strong bonding with the insulation material, significantly improving the cable's heat resistance, aging resistance, and mechanical strength.

[0032] In an embodiment of the present invention, the insulating layer comprises the following raw materials in parts by weight: 25-35 parts of styrene-butadiene rubber, 15-30 parts of high styrene, 16-22 parts of stearic acid, 5-8 parts of modified aramid fiber, 3-5 parts of white carbon black, 3-8 parts of accelerator, 2-7 parts of zinc oxide, 3-6 parts of antioxidant, 1-5 parts of paraffin, and 1-5 parts of aromatic oil.

[0033] Preferably, the insulation layer comprises the following raw materials, by weight: 30 parts styrene-butadiene rubber, 28 parts high-styrene copolymer, 20 parts stearic acid, 7 parts modified aramid fiber, 4 parts white carbon black, 6 parts accelerator, 5 parts zinc oxide, 4 parts antioxidant, 3 parts paraffin, and 3 parts aromatic oil. The accelerator is zinc dimethyldithiocarbamate (ZDC) or tetramethylthiuram disulfide (TMTD). These accelerators effectively accelerate the vulcanization process of the rubber and increase the crosslink density of the insulation layer, thereby enhancing the mechanical strength and heat resistance of the cable. They also improve the processing properties of the insulation layer, facilitating a smoother manufacturing process. The antioxidant is a hindered phenolic antioxidant, such as 2,6-di-tert-butyl-4-methylphenol (BHT) or N,N'-diphenyl-p-phenylenediamine (DPPD). It effectively inhibits oxidative degradation of the rubber material during processing, storage, and use, improving the aging resistance of the insulation layer and thus extending the service life of the cable.

[0034] By optimizing the proportions of each component, the insulation layer exhibits excellent heat resistance, tensile strength, and tear resistance, ensuring that the cable can maintain stable electrical insulation performance under extreme conditions such as high temperature and high pressure, significantly extending the cable's service life and meeting the stringent requirements of high-end applications for high-reliability cables.

[0035] In an embodiment of the present invention, the aramid fiber column includes a number of aramid fibers with a diameter of more than 1000d twisted together. The twisting method adopts a unique spiral structure, which enhances the friction between the fibers, further improves the stability and tensile strength of the overall structure, ensures that the fiber column is not easy to loosen under complex stress environments, and effectively maintains the mechanical properties and electrical insulation of the cable. In addition, a protective coating is provided on the surface of the fiber column. The protective coating is composed of nano-silica and fluorocarbon resin, and the thickness is controlled at 5-10 microns, which significantly improves the weather resistance and aging resistance of the fiber column, ensuring that it can still maintain excellent performance in long-term exposure to ultraviolet rays and chemical corrosion environments, further improving the overall reliability and service life of the cable. In the protective coating, nano-silica is evenly dispersed in the fluorocarbon resin to form a dense protective layer, which improves the chemical stability of the aramid fiber column and further enhances the durability of the cable.

[0036] In an embodiment of the present invention, the copper foil wire has a thickness of 5-15 μm, a pitch to copper foil width ratio of 1:1-1:3, and a winding angle of 40-50°.

[0037] In an embodiment of the present invention, the core is positioned within the cabling structure layer, while the sheath is positioned externally. The cabling structure is filled with several aramid fiber columns. The core and sheath are securely fastened with a high-strength adhesive, ensuring structural integrity and enhancing impact resistance. The evenly distributed aramid fiber columns effectively disperse stress, enhancing the cable's tensile and bending resistance, and ensuring excellent electrical performance and mechanical stability under dynamic loads.

[0038] In an embodiment of the present invention, the sheath includes an inner sheath, a shielding layer, and an outer sheath. The shielding layer includes a conductive yarn woven from a blend of copper fiber and aramid fiber, wherein the copper fiber accounts for 55-60 parts by mass and the aramid fiber accounts for 40-45 parts by mass. The shielding layer is woven from a conductive yarn blended with copper fiber and aramid fiber having a diameter of 10-20 μm, with a coverage rate of ≥95%. The shielding layer has excellent conductivity and excellent flexibility. The woven shielding layer has the characteristics of high shielding effectiveness, light weight, high flexibility, fatigue resistance, and high mechanical strength. It is particularly suitable for ultra-flexible cables and solves the problems of poor flexibility of pure copper wire braiding, easy breakage due to frequent bending or bending with a small bending radius, and hard tips that can easily pierce the insulation after breaking. Compared with traditional copper wire braiding, the conductive yarn braiding not only has higher flexibility, but also can effectively shield electromagnetic interference and improve signal transmission quality. The conductive yarn braiding is tightly covered, effectively shielding electromagnetic interference and ensuring signal transmission stability. The precisely balanced ratio of copper and aramid fibers in the shield ensures excellent conductivity while also enhancing tensile strength and abrasion resistance, further enhancing the shielding effectiveness. The tightly woven mesh effectively blocks the intrusion of external electromagnetic waves, ensuring the cable maintains efficient and stable signal transmission even in complex electromagnetic environments.

[0039] In an embodiment of the present invention, the inner sheath and the outer sheath include the following raw materials in parts by weight: 80-100 parts of styrene-butadiene rubber, 10-15 parts of nano-silica, 20-30 parts of polyvinyl chloride, 1-5 parts of calcium carbonate, 1-2 parts of 2,6-di-tert-butyl-4-methylphenol, 0.5-1 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], 0.5-1 parts of benzotriazole ultraviolet absorber, 3-5 parts of silicone hydrophobic agent, 5-8 parts of expanded graphite, 0.5-1 parts of silane coupling agent, and 1-5 parts of polyethylene wax.

[0040] In an embodiment of the present invention, the inner sheath is coated with a flame-retardant coating, and the outer sheath is provided with a wear-resistant coating. The flame-retardant coating is a colloidal graphite powder coating or a colloidal molybdenum disulfide coating. The wear-resistant coating is a mixture of nanodiamond particles and polyurethane resin in a ratio of 1-3:5-8, with a thickness of 20-30 μm, significantly improving the outer sheath's wear resistance and scratch resistance.

[0041] The structure of the super flexible cable for humanoid robots of the present invention is as follows: Figure 1 shown.

[0042] An ultra-flexible cable for humanoid robots comprises a core, an insulation layer, and a sheath. The core comprises copper foil filaments 1 and aramid fiber rods 2. Several copper foil filaments 1 are spirally twisted around the aramid fiber rods 2. The aramid fiber rods 2 are composed of several twisted aramid fibers of 1000 denier or greater. An insulation layer 3 wraps around the outer core layer. The core is positioned within the cabling structure layer, and the sheath is positioned outside the cabling structure. The cabling structure is filled with several aramid fiber rods 2. The sheath comprises, from the inside out, an inner sheath 4, a shielding layer 5, and an outer sheath 6.

[0043] The core structure not only retains the high conductivity of the copper foil, but the addition of aramid fiber significantly enhances the conductor's tensile strength and flex resistance, making the cable less susceptible to breakage under frequent bending and extending its service life. Field measurements show a tensile strength increase of over 200% compared to traditional copper conductors. The aramid fiber filling in the cabling structure not only provides additional tensile support but also effectively distributes stress generated during cable bending, minimizing internal damage. The cabling pitch ratio is controlled between 4 and 6 times. This small cabling pitch-to-diameter ratio reduces internal stress concentration during bending or stretching, thereby reducing the risk of fatigue damage from long-term stress and optimizing the cable's flexibility and flex resistance. This significantly extends the cable's service life and improves its reliability. The inner sheath is formed through an extrusion process, closely fitting the insulation layer and enhancing the cable's structural stability and environmental adaptability. The outer sheath provides the cable with a final protective layer, enhancing its resistance to external environments, such as abrasion, weathering, and water.

[0044] An embodiment of the second aspect of the present application provides a method for preparing an ultra-flexible cable for a humanoid robot, comprising the following steps: S1: Use a coating machine to spirally wrap the copper foil around the aramid fiber column, and then twist several copper foils in layers to form a conductor; S2: Weighing styrene-butadiene rubber, high styrene, stearic acid, aramid fiber, white carbon black, accelerator, zinc oxide, antioxidant, paraffin wax, and aromatic oil in proportion, mixing and kneading a mixture, and extruding the mixture into an insulating layer, which is then coated on the conductor to form an insulating core; S3: twisting a plurality of the insulating cores to form a cable core wire; S4: Styrene-butadiene rubber, nano-silica, polyvinyl chloride, calcium carbonate, 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], benzotriazole ultraviolet absorber, silicone hydrophobic agent, expanded graphite, silane coupling agent, and polyethylene wax are weighed in proportion to prepare an inner sheath; S5: Wrap the inner sheath around the outer layer of the cable core wire, and then wrap the shielding layer and the outer sheath in sequence to obtain an ultra-flexible cable for a humanoid robot.

[0045] Example 1 An ultra-flexible cable for a humanoid robot comprises a core, an insulating layer, and a sheath. The core comprises a conductor formed by twisting copper foil wires, wherein the copper foil wires are a spiral structure with embedded aramid fiber columns. The insulating layer includes the following raw materials in parts by weight: 30 parts of styrene-butadiene rubber, 25 parts of high styrene, 20 parts of stearic acid, 6 parts of modified aramid fiber, 4 parts of white carbon black, 7 parts of accelerator, 6 parts of zinc oxide, 5 parts of antioxidant, 3 parts of paraffin, and 3 parts of aromatic oil.

[0046] The modified aramid fiber is obtained by treating the aramid fiber with a LiCl-polyvinyl pyrrolidone solution and then grafting the aramid fiber with a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate.

[0047] The modified aramid fiber preparation method comprises: dissolving LiCl and polyvinyl pyrrolidone in a 3-5 times amount of ethanol solution according to a proportion, heating until completely dissolved to obtain a uniform and transparent LiCl-polyvinyl pyrrolidone solution. Subsequently, the aramid fiber is immersed in the LiCl-polyvinyl pyrrolidone solution and stirred at a constant temperature for 2-4 hours to ensure that the fiber is fully infiltrated and the LiCl-polyvinyl pyrrolidone effectively adheres to the surface of the aramid fiber, maintaining the surface of the aramid fiber moist. The aramid fiber is then immersed in a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate and ultrasonicated for 25 minutes. The fiber is then placed in a 90°C oven for 1 hour and then in a 140°C oven for 4 hours to completely evaporate the toluene. The fiber is removed, immersed in deionized water at 100°C for 1 hour, and dried to obtain the modified aramid fiber.

[0048] The inner sheath and the outer sheath include the following raw materials in parts by weight: 90 parts of styrene-butadiene rubber, 12 parts of nano-silica, 26 parts of polyvinyl chloride, 3 parts of calcium carbonate, 1.5 parts of 2,6-di-tert-butyl-4-methylphenol, 0.8 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], 0.8 parts of benzotriazole ultraviolet absorber, 4 parts of silicone hydrophobic agent, 7 parts of expanded graphite, 0.8 parts of silane coupling agent, and 2 parts of polyethylene wax.

[0049] The present application also provides a method for preparing an ultra-flexible cable for a humanoid robot, comprising the following steps: S1: Use a coating machine to spirally wrap the copper foil around the aramid fiber column, and then twist several copper foils in layers to form a conductor; S2: Weighing styrene-butadiene rubber, high styrene, stearic acid, aramid fiber, white carbon black, accelerator, zinc oxide, antioxidant, paraffin wax, and aromatic oil in proportion, mixing and kneading a mixture, and extruding the mixture into an insulating layer, which is then coated on the conductor to form an insulating core; S3: twisting a plurality of the insulating cores to form a cable core wire; S4: Styrene-butadiene rubber, nano-silica, polyvinyl chloride, calcium carbonate, 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], benzotriazole ultraviolet absorber, silicone hydrophobic agent, expanded graphite, silane coupling agent, and polyethylene wax are weighed in proportion to prepare an inner sheath; S5: Wrap the inner sheath around the outer layer of the cable core wire, and then wrap the shielding layer and the outer sheath in sequence to obtain an ultra-flexible cable for a humanoid robot.

[0050] Example 2 This embodiment is basically the same as embodiment 1, except that the insulating layer contains 25 parts of styrene-butadiene rubber, 30 parts of high styrene, 16 parts of stearic acid, and 5 parts of modified aramid fiber.

[0051] Example 3 This embodiment is basically the same as embodiment 1, except that the insulating layer contains 35 parts of styrene-butadiene rubber, 15 parts of high styrene, 22 parts of stearic acid, and 8 parts of modified aramid fiber.

[0052] Example 4 This embodiment is basically the same as embodiment 1, except that the insulating layer contains 28 parts of styrene-butadiene rubber, 25 parts of high styrene, 18 parts of stearic acid, and 7 parts of modified aramid fiber.

[0053] Example 5 This embodiment is substantially the same as embodiment 1, except that in the preparation method of the modified aramid fiber, the aramid fiber is immersed in a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate and ultrasonicated for 20 minutes; the fiber is then placed in an oven at 100°C for 1.5 hours and then in an oven at 130°C for 5 hours to completely evaporate the toluene.

[0054] Example 6 This embodiment is basically the same as Example 1, except that in the preparation method of the modified aramid fiber, the aramid fiber is immersed in a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate and ultrasonicated for 30 minutes; then placed in a 95°C oven for 1 hour and in a 150°C oven for 3 hours to completely evaporate the toluene.

[0055] Example 7 This embodiment is basically the same as Example 1, except that the raw materials of the inner sheath and the outer sheath include 80 parts of styrene-butadiene rubber, 10 parts of nano-silica, 20 parts of polyvinyl chloride, 5 parts of calcium carbonate, 1.8 parts of 2,6-di-tert-butyl-4-methylphenol, 1 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], 1 part of benzotriazole ultraviolet absorber, 4 parts of silicone hydrophobic agent, 8 parts of expanded graphite, 1 part of silane coupling agent, and 4 parts of polyethylene wax.

[0056] Example 8 This embodiment is basically the same as Example 1, except that the raw materials of the inner sheath and the outer sheath include 100 parts of styrene-butadiene rubber, 15 parts of nano-silica, 30 parts of polyvinyl chloride, 1 part of calcium carbonate, 1.2 parts of 2,6-di-tert-butyl-4-methylphenol, 0.5 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], 0.5 parts of benzotriazole ultraviolet absorber, 3 parts of silicone hydrophobic agent, 5 parts of expanded graphite, 0.5 parts of silane coupling agent, and 2 parts of polyethylene wax.

[0057] Comparative Example 1 This comparative example is basically the same as Example 1, except that no aramid fiber column is provided in the conductor.

[0058] Comparative Example 2 This comparative example is basically the same as Example 1, except that the copper foil wire is not a spiral structure.

[0059] Comparative Example 3 This comparative example is basically the same as Example 1, except that the aramid fibers in the insulating layer are not modified.

[0060] Performance Testing The impact strength of the cables in Examples 1-8 and Comparative Examples 1-3 was tested according to the standard GB / T1451-2005, "Test Method for Charpy Impact Toughness of Fiber-Reinforced Plastics," and the tensile strength of the cables in Examples 1-8 and Comparative Examples 1-3 was tested according to the standard GB / T2951.11-2008, "General Test Methods for Insulation and Sheathing Materials of Electric and Optical Cables." The flexibility of the cables in Examples 1-8 and Comparative Examples 1-3 was tested according to the standard GB / T 238-2013, "Test Method for Repeated Bending of Metallic Wires." A bending force was applied at a uniform rate of 1–2 times / second for 30 minutes, and the cables were observed for the presence of creases. The results are shown in Table 1.

[0061]

[0062] As can be seen from the table above, Examples 1-8 of my invention use copper foil with a spiral structure embedded in aramid fiber columns to form a conductor. The aramid fiber itself has the characteristics of high modulus and high strength. After being embedded in the copper foil, the conductor's tensile strength is significantly improved. The spiral structure of the copper foil combined with the flexibility of the aramid fiber allows the copper foil to be repeatedly bent in complex wiring environments without breaking or deforming easily. The modified aramid fiber in the insulation layer of the present invention is treated with a LiCl-polyvinyl pyrrolidone solution. The arrangement of the aramid molecular chain is adjusted through ionic action, so that the tensile strength and shear strength of the modified aramid fiber are improved. Polyvinyl pyrrolidone can improve the dispersibility of LiCl, so that the strength of the aramid fiber is uniformly increased. The present invention uses a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate to graft aramid fiber. The grafted aramid fiber is more tightly bonded to the other materials of the insulation layer, effectively improving the overall flexibility, durability and anti-aging performance of the cable.

[0063] It can be seen from Comparative Example 1 that when the aramid fiber column is not provided in the conductor of the present invention, the tensile strength and impact strength of the cable are significantly reduced, and the flexibility is worse; it can be seen from Comparative Example 2 that when the copper foil adopts an ordinary structure and does not adopt a spiral structure, the tensile strength and impact strength of the cable are reduced; it can be seen from Comparative Example 3 that the aramid fiber in the insulating layer is not modified, and the tensile strength and impact strength of the cable are reduced compared with the modified aramid fiber.

[0064] In summary, the cable of the present invention has excellent softness and is suitable for various complex and narrow installation spaces and application scenarios with frequent bending; the addition of modified aramid fiber and the optimized cabling structure significantly improve the tensile strength and bending fatigue resistance of the cable, and extend its service life; the shielding layer woven with conductive yarn ensures stable signal transmission and effectively resists electromagnetic interference.

[0065] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. An ultra-flexible cable for a humanoid robot, comprising a core, an insulation layer and a sheath, characterized in that: The core includes copper foil wire and aramid fiber column, and several copper foil wires are spirally twisted with the aramid fiber column as the center; the raw material for preparing the insulating layer includes modified aramid fiber, and the modified aramid fiber is obtained by treating aramid fiber with LiCl-polyvinyl pyrrolidone solution and then grafting aramid fiber with toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate.

2. The ultra-flexible cable for a humanoid robot according to claim 1, wherein: The mass fraction of LiCl in the LiCl-polyvinyl pyrrolidone solution is 35-42%.

3. The ultra-flexible cable for a humanoid robot according to claim 1, wherein: The insulating layer comprises the following raw materials in parts by weight: 25-35 parts of styrene-butadiene rubber, 15-30 parts of high styrene, 16-22 parts of stearic acid, 5-8 parts of modified aramid fiber, 3-5 parts of white carbon black, 3-8 parts of accelerator, 2-7 parts of zinc oxide, 3-6 parts of antioxidant, 1-5 parts of paraffin, and 1-5 parts of aromatic oil.

4. The ultra-flexible cable for a humanoid robot according to claim 1, wherein: The aramid fiber column is composed of a plurality of aramid fibers with a density of more than 1000d twisted together, and a protective coating is provided on the surface of the aramid fiber column.

5. The ultra-flexible cable for a humanoid robot according to claim 1, wherein: The copper foil wire has a thickness of 5-15 μm, a pitch to copper foil width ratio of 1:1-1:3, and a winding angle of 40-50°.

6. The ultra-flexible cable for a humanoid robot according to claim 1, wherein: The core is arranged in the cabling structure layer, the sheath is arranged outside the cabling structure, and the middle of the cabling structure is filled with a plurality of aramid fiber columns.

7. The ultra-flexible cable for a humanoid robot according to claim 1, wherein: The sheath comprises an inner sheath, a shielding layer and an outer sheath. The shielding layer comprises a conductive yarn woven from a blend of copper fiber and aramid fiber, wherein the mass fraction of the copper fiber is 55-60 parts and the mass fraction of the aramid fiber is 40-45 parts.

8. The ultra-flexible cable for a humanoid robot according to claim 7, wherein: The inner and outer sheaths include the following raw materials in parts by weight: 80-100 parts of styrene-butadiene rubber, 10-15 parts of nano-silicon dioxide, 20-30 parts of polyvinyl chloride, 1-5 parts of calcium carbonate, 1-2 parts of 2,6-di-tert-butyl-4-methylphenol, 0.5-1 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], 0.5-1 parts of benzotriazole ultraviolet absorber, 3-5 parts of organic silicon hydrophobic agent, 5-8 parts of expanded graphite, 0.5-1 parts of silane coupling agent, and 1-5 parts of polyethylene wax.

9. The ultra-flexible cable for a humanoid robot according to claim 7, wherein: The surface of the inner sheath is coated with a flame retardant coating, and the outer surface of the outer sheath is provided with a wear-resistant coating.

10. A method for preparing an ultra-flexible cable for a humanoid robot according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: Use a coating machine to spirally wrap the copper foil around the aramid fiber column, and then twist several copper foils in layers to form a conductor; S2: Weighing styrene-butadiene rubber, high styrene, stearic acid, aramid fiber, white carbon black, accelerator, zinc oxide, antioxidant, paraffin wax, and aromatic oil in proportion, mixing and kneading a mixture, and extruding the mixture into an insulating layer, which is then coated on the conductor to form an insulating core; S3: twisting a plurality of the insulating cores to form a cable core wire; S4: Styrene-butadiene rubber, nano-silica, polyvinyl chloride, calcium carbonate, 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate], benzotriazole ultraviolet absorber, silicone hydrophobic agent, expanded graphite, silane coupling agent, and polyethylene wax are weighed in proportion to prepare an inner sheath and an outer sheath; S5: Wrap the inner sheath around the outer layer of the cable core wire, and then wrap the shielding layer and the outer sheath in sequence to obtain an ultra-flexible cable for a humanoid robot.

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