Super flexible cable for humanoid robots and method for manufacturing the same

Abstract

The application provides a super-flexible cable for a humanoid robot and a preparation method thereof, wherein the super-flexible cable for the humanoid robot comprises a core body, an insulation layer and a sheath, the core body comprises copper foil filaments and aramid fiber columns, and the copper foil filaments are spirally twisted around the aramid fiber columns; the insulation layer comprises modified aramid fibers, the modified aramid fibers are obtained by treating aramid fibers with a LiCl-polyvinylpyrrolidone solution, and then grafting the aramid fibers with a trimethoxysilane / 1,6-hexane diisocyanate toluene solution. The cable has excellent softness, is suitable for various complex, narrow installation spaces and frequent bending application scenarios, the addition of the modified aramid fibers 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] This application relates to the field of wire and cable technology, and in particular to an ultra-flexible cable for humanoid robots and its preparation method. Background Technology

[0002] Cables used in robots must use annealed copper wire and may include tensile strength components; the insulation thickness must be at least 90% of the nominal value. Mechanical life tests, such as 5 million drag chain cycles and 1 million 90-degree bending cycles, are conducted to ensure the cable's reliability under the high-dynamic operating conditions of industrial robots.

[0003] Traditional cables, while pursuing high conductivity, often neglect flexibility and bending fatigue resistance, which is particularly limiting in applications requiring frequent movement or bending. While existing flexible cables have shown some improvement, most rely on single materials or structural modifications, making it difficult to achieve 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 superior fatigue resistance, is of paramount importance. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems, and its purpose is to provide an ultra-flexible cable for humanoid robots and a method for manufacturing the same.

[0005] Specifically, the first aspect of this application provides an ultra-flexible cable for humanoid robots, comprising a core, an insulation layer, and a sheath. The core comprises copper foil wires and aramid fiber pillars, with a plurality of copper foil wires spirally twisted around the aramid fiber pillars. The insulation layer is prepared from styrene-butadiene rubber, high styrene, and modified aramid fibers. The modified aramid fibers are obtained by treating aramid fibers with LiCl-polyvinylpyrrolidone solution and then grafting aramid fibers with a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate.

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

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

[0008] Furthermore, the aramid fiber column is composed of several aramid fibers with a diameter of 1000 or more twisted together, and the surface of the aramid fiber column is also provided with a protective coating.

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

[0010] Furthermore, the core is disposed within the cable structure layer, the sheath is disposed outside the cable structure, and the middle of the cable structure is filled with several aramid fiber pillars.

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

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

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

[0014] The second aspect of this application provides a method for manufacturing the aforementioned ultra-flexible cable for humanoid robots, comprising the following steps:

[0015] S1: Using a coating machine, copper foil wires are spirally wound around an aramid fiber column, and then several copper foil wires are twisted in layers to form a conductor;

[0016] S2: Weigh out styrene-butadiene rubber, high styrene, stearic acid, aramid fiber, silica, accelerator, zinc oxide, antioxidant, paraffin wax, and aromatic oil in proportion and mix them to obtain a mixture. Extrude the mixture into an insulating layer and coat it onto the conductor to form an insulating core.

[0017] S3: Several insulating cores are twisted together to form a cable core wire;

[0018] S4: Weigh out 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 UV absorber, organosilicon hydrophobic agent, expanded graphite, silane coupling agent, and polyethylene wax in proportion to make an inner sheath.

[0019] S5: Wrap the inner sheath around the outer layer of the cable core, and then wrap the shielding layer and the outer sheath in sequence to obtain the ultra-flexible cable for humanoid robots.

[0020] The present invention has the following beneficial effects:

[0021] (1) The ultra-flexible cable core for humanoid robots of the present invention is formed by spirally twisting several copper foil wires around an aramid fiber column. 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 allows the wire to maintain its integrity when subjected to external tensile force, which is especially suitable for scenarios that require frequent movement or bending (such as robot cables, drag chain cables, etc.). The spiral structure of the copper foil wire combined with the flexibility of the aramid fiber allows the copper foil wire to be bent repeatedly in complex wiring environments without breaking or deforming. Its 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.

[0022] (2) The modified aramid fibers in the insulation layer of this invention are treated with a LiCl-polyvinylpyrrolidone solution. LiCl can be loaded into the aramid fibers to break 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 fibers. The fiber surface is etched with grooves, increasing the surface roughness and thus improving the bonding performance of aramid fibers with styrene-butadiene rubber and high styrene. At the same time, the arrangement of aramid molecular chains is adjusted through ionic action, thereby improving the tensile strength and shear strength of the modified aramid fibers. Polyvinylpyrrolidone can improve the dispersibility of LiCl, making LiCl more uniformly dispersed in the solution, reducing the agglomeration of aramid fibers, and making the strength of aramid fibers uniformly increase. The treated aramid fibers are also grafted with a toluene solution of trimethoxysilane / 1,6-hexamethylenediisocyanate. The grafted aramid fibers are more tightly bonded with other materials in the insulation 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 the high reliability requirements. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this drawing or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of the ultra-flexible cable for the humanoid robot of the present invention.

[0025] Explanation of icon numbers:

[0026] 1-Copper foil wire; 2-Aramid fiber column; 3-Insulation layer; 4-Inner sheath; 5-Shielding layer; 6-Outer sheath.

[0027] The purpose, features, and advantages of this accompanying drawing will be further explained in conjunction with the embodiments and with reference to the accompanying drawing. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following description and illustration are provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0029] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0030] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0031] An embodiment of the first aspect of this application provides an ultra-flexible cable for humanoid robots, comprising a core, an insulation layer, and a sheath. The core comprises copper foil wires and aramid fiber pillars, wherein a plurality of the copper foil wires are spirally twisted around the aramid fiber pillars. The insulation layer is prepared from modified aramid fibers, wherein the modified aramid fibers are obtained by treating aramid fibers with a LiCl-polyvinylpyrrolidone solution and then grafting aramid fibers with a toluene solution of trimethoxysilane / 1,6-hexamethylenediisocyanate.

[0032] The ultra-flexible cable core for humanoid robots of this invention is formed by spirally twisting several copper foil wires around an aramid fiber column. The aramid fiber itself possesses high modulus and high strength; embedding it into the copper foil wire significantly improves the conductor's tensile strength. This structure allows the conductor to maintain its integrity even under tensile stress, making it particularly suitable for scenarios requiring frequent movement or bending (such as robot cables and drag chain cables). Furthermore, the spiral structure of the copper foil wires combined with the flexibility of the aramid fiber allows the copper foil wires to be repeatedly bent in complex wiring environments without easily breaking or deforming. Its flexibility surpasses that of traditional pure copper wires, making it suitable for fields with high flexibility requirements, such as smart wearable devices and medical devices.

[0033] The modified aramid fibers in the insulating layer of this invention are treated with a LiCl-polyvinylpyrrolidone solution. LiCl can be loaded onto the aramid fibers, disrupting the hydrogen bonds in the aramid fiber molecules. This increases the nitrogen content and the number of -NH groups on the aramid fiber surface, causing grooves to form on the fiber surface and increasing surface roughness. This improves the bonding performance of the aramid fibers with insulating materials such as styrene-butadiene rubber and high-styrene. Simultaneously, the ionic interaction regulates the aramid molecular chain arrangement, improving the tensile and shear strength of the modified aramid fibers. Polyvinylpyrrolidone improves the dispersibility of LiCl, dispersing it more uniformly in the solution, reducing the agglomeration of the aramid fibers, and resulting in a more uniform increase in aramid fiber strength. Furthermore, polyvinylpyrrolidone possesses certain toughening properties, further enhancing the flexibility of the aramid fibers.

[0034] This 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 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.

[0035] In embodiments of the present invention, the mass fraction of LiCl in the LiCl-polyvinylpyrrolidone solution is 35-42%. Preferably, the mass fraction of LiCl is any one of 35%, 37%, 39%, 40%, 42%, etc. Furthermore, the LiCl-polyvinylpyrrolidone solution ensures uniform dispersion of LiCl and uniform reinforcement of aramid fibers, further optimizing the overall performance of the insulation layer and improving 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 fibers is significantly improved, enhancing the interfacial bonding force with the insulation layer material, ensuring that the cable maintains 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 applications.

[0036] The method for preparing the modified aramid fiber is as follows:

[0037] Weigh out LiCl and polyvinylpyrrolidone in 3-5 times their volume of ethanol solution according to the specified ratio, and heat until completely dissolved to obtain a uniform and transparent LiCl-polyvinylpyrrolidone solution.

[0038] Add anhydrous toluene to the reaction vessel, and slowly add trimethoxysilane dropwise while stirring, controlling the dropping rate to avoid local overheating. Maintain the temperature at 20-25°C and stir for 20-40 minutes until completely dissolved. Slowly add 1,6-hexamethylene diisocyanate through a constant-pressure dropping funnel. The mass ratio of trimethoxysilane to 1,6-hexamethylene diisocyanate is 3:2, and the amount of anhydrous toluene is 5 times the mass of trimethoxysilane to 1,6-hexamethylene diisocyanate. Maintain the system temperature at 20-25°C. After the addition is complete, continue stirring for 1-2 hours to ensure uniform mixing, thus obtaining a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate.

[0039] Aramid fibers are immersed in a LiCl-polyvinylpyrrolidone solution and stirred at a constant temperature for 2-4 hours to ensure full wetting and effective adhesion of LiCl-polyvinylpyrrolidone to the surface of the aramid fibers, keeping the surface moist. Then, the aramid fibers are immersed in a trimethoxysilane / 1,6-hexamethylene diisocyanate toluene solution and sonicated for 20-30 minutes. Afterward, they are placed in a 90-100℃ oven for 1-1.5 hours, followed by a 130-150℃ oven for 3-5 hours to allow complete evaporation of the toluene. The fibers are then removed, soaked in deionized water at 100℃ for 1-2 hours, and dried to obtain the modified aramid fibers. The modified aramid fibers prepared by this method have moderate surface roughness, stable structure, and strong bonding with the insulation material, significantly improving the heat resistance, aging resistance, and mechanical strength of the cable.

[0040] In an embodiment of the present invention, the insulating layer comprises the following raw materials by weight: 25-35 parts styrene-butadiene rubber, 15-30 parts high styrene, 16-22 parts stearic acid, 5-8 parts modified aramid fiber, 3-5 parts silica, 3-8 parts accelerator, 2-7 parts zinc oxide, 3-6 parts antioxidant, 1-5 parts paraffin wax, and 1-5 parts aromatic oil.

[0041] Preferably, the insulation layer comprises the following raw materials by weight: 30 parts styrene-butadiene rubber, 28 parts high-styrene, 20 parts stearic acid, 7 parts modified aramid fiber, 4 parts silica, 6 parts accelerator, 5 parts zinc oxide, 4 parts antioxidant, 3 parts paraffin wax, and 3 parts aromatic oil. The accelerator is zinc dimethyl dithiocarbamate (ZDC) or tetramethylthiuram disulfide (TMTD). These two accelerators effectively accelerate the vulcanization process of rubber, increase the crosslinking density of the insulation layer, thereby enhancing the mechanical strength and heat resistance of the cable. Simultaneously, they also improve the processing performance of the insulation layer, making the preparation process smoother. The antioxidant is a hindered phenolic antioxidant, such as 2,6-di-tert-butyl-4-methylphenol (BHT) or N,N'-diphenyl-p-phenylenediamine (DPPD), which effectively inhibits the oxidative degradation of rubber materials during processing, storage, and use, improves the aging resistance of the insulation layer, and thus extends the service life of the cable.

[0042] By optimizing the proportions of each component, the insulation layer exhibits excellent heat resistance, tensile strength, and tear resistance, ensuring that the cable maintains 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-reliability cables in high-end applications.

[0043] In embodiments of the present invention, the aramid fiber column comprises a plurality of aramid fibers with a density of 1000d or higher twisted together. The twisting method employs a unique helical structure, enhancing the friction between the fibers, further improving the overall structural stability and tensile strength, ensuring that the fiber column does not easily loosen under complex stress environments, and effectively maintaining the cable's mechanical properties and electrical insulation. Furthermore, a protective coating is provided on the surface of the fiber column. This protective coating is composed of nano-silica and fluorocarbon resin, with a thickness controlled at 5-10 micrometers. This significantly improves the fiber column's weather resistance and anti-aging properties, ensuring excellent performance even after long-term exposure to ultraviolet radiation and chemical corrosion, further enhancing the cable's overall reliability and service life. In the protective coating, nano-silica is uniformly dispersed in the fluorocarbon resin, forming a dense protective layer, improving the chemical stability of the aramid fiber column and further enhancing the cable's durability.

[0044] In an embodiment of the present invention, the copper foil wire has a thickness of 5-15 μm, a pitch-to-width ratio of 1:1-1:3, and a winding angle of 40-50°.

[0045] In an embodiment of the present invention, the core is disposed within the cabling structure layer, and the sheath is disposed outside the cabling structure. The cabling structure is filled with a plurality of aramid fiber pillars. The core and sheath are tightly fixed together with a high-strength adhesive to ensure structural integrity and improve impact resistance. The aramid fiber pillars are evenly distributed, effectively dispersing stress and enhancing the cable's tensile and bending resistance, ensuring excellent electrical performance and mechanical stability under dynamic loads.

[0046] In embodiments of the present invention, the sheath includes an inner sheath, a shielding layer, and an outer sheath. The shielding layer is woven from conductive yarns blended from copper fibers and aramid fibers, wherein the mass fraction of copper fibers is 55-60 parts and the mass fraction of aramid fibers is 40-45 parts. The shielding layer is woven from conductive yarns blended from copper fibers and aramid fibers with a diameter of 10-20 μm, with a coverage rate ≥95%. It has excellent conductivity and flexibility. The woven shielding layer has high shielding effectiveness, is lightweight, highly flexible, fatigue-resistant, and has high mechanical strength. It is particularly suitable for ultra-flexible cables, solving the problems of poor flexibility of pure copper wire braids, easy breakage due to frequent bending or bending at small radii, and hardened tips that can easily damage the insulation after breakage. Compared to traditional copper wire braiding, conductive yarn braiding not only has higher flexibility but also effectively shields electromagnetic interference, improving signal transmission quality. The tight coverage of the conductive yarn braid effectively shields electromagnetic interference, ensuring signal transmission stability. The ratio of copper fiber to aramid fiber in the shielding layer is precisely adjusted to ensure good conductivity while improving tensile strength and abrasion resistance, further enhancing the shielding effect. The tightly woven mesh structure effectively prevents the intrusion of external electromagnetic waves, ensuring that the cable maintains efficient and stable signal transmission capabilities even in complex electromagnetic environments.

[0047] In embodiments of the present invention, the inner and outer sheaths, by weight, comprise the following raw materials: 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 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl,4-hydroxyphenyl)propionate], 0.5-1 part of benzotriazole ultraviolet absorber, 3-5 parts of organosilicon hydrophobic agent, 5-8 parts of expanded graphite, 0.5-1 part of silane coupling agent, and 1-5 parts of polyethylene wax.

[0048] In an embodiment of the present invention, 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. The flame-retardant coating is a colloidal graphite powder coating or a colloidal molybdenum disulfide coating. The wear-resistant coating is composed of nanodiamond particles and polyurethane resin mixed in a ratio of 1-3:5-8, with a thickness of 20-30 μm, significantly improving the wear resistance and scratch resistance of the outer sheath.

[0049] The structure of the ultra-flexible cable for humanoid robots of the present invention is as follows: Figure 1 As shown.

[0050] A flexible cable for humanoid robots includes a core, an insulation layer, and a sheath. The core comprises copper foil wires 1 and aramid fiber pillars 2, with several copper foil wires 1 spirally twisted around the aramid fiber pillars 2. The aramid fiber pillars 2 are composed of several aramid fibers with a density of 1000d or higher twisted together. An insulation layer 3 is wrapped around the outer layer of the core. The core is disposed within the cable structure layer, and the sheath is disposed outside the cable structure. Several aramid fiber pillars 2 are filled in the middle of the cable structure. The sheath comprises, from the inside out, an inner sheath 4, a shielding layer 5, and an outer sheath 6.

[0051] The core's structural design not only retains the high conductivity of copper foil wires, but the addition of aramid fibers significantly enhances the conductor's tensile strength and bending resistance, making the cable less prone to breakage under frequent bending and improving its service life. Actual measurements show that the tensile strength is over 200% higher than that of traditional copper conductors. The aramid fiber filling in the cabling structure not only provides additional tensile support but also effectively disperses stress generated during bending, reducing internal damage. The cabling pitch ratio is controlled between 4 and 6; a small pitch ratio reduces internal stress concentration during bending or stretching, thereby lowering the risk of fatigue damage from long-term stress and optimizing the cable's flexibility and bending resistance. This greatly extends the cable's service life and improves its reliability. The inner sheath is formed through an extrusion process, tightly fitting the insulation layer and enhancing the cable's structural stability and environmental adaptability. The outer sheath provides the final protective layer, enhancing its resistance to external environments, such as abrasion resistance, weather resistance, and water resistance.

[0052] A second aspect of this application provides a method for fabricating the aforementioned ultra-flexible cable for humanoid robots, comprising the following steps:

[0053] S1: Using a coating machine, copper foil wires are spirally wound around an aramid fiber column, and then several copper foil wires are twisted in layers to form a conductor;

[0054] S2: Weigh out styrene-butadiene rubber, high styrene, stearic acid, aramid fiber, silica, accelerator, zinc oxide, antioxidant, paraffin wax, and aromatic oil in proportion and mix them to obtain a mixture. Extrude the mixture into an insulating layer and coat it onto the conductor to form an insulating core.

[0055] S3: Several insulating cores are twisted together to form a cable core wire;

[0056] S4: Weigh out 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 UV absorber, organosilicon hydrophobic agent, expanded graphite, silane coupling agent, and polyethylene wax in proportion to make an inner sheath.

[0057] S5: Wrap the inner sheath around the outer layer of the cable core, and then wrap the shielding layer and the outer sheath in sequence to obtain the ultra-flexible cable for humanoid robots.

[0058] Example 1

[0059] An ultra-flexible cable for humanoid robots includes a core, an insulation layer, and a sheath. The core includes a conductor made of twisted copper foil wires, wherein the copper foil wires have a helical structure with embedded aramid fiber pillars.

[0060] The insulating layer comprises the following raw materials by weight: 30 parts styrene-butadiene rubber, 25 parts high styrene, 20 parts stearic acid, 6 parts modified aramid fiber, 4 parts silica, 7 parts accelerator, 6 parts zinc oxide, 5 parts antioxidant, 3 parts paraffin wax, and 3 parts aromatic oil.

[0061] The modified aramid fiber is obtained by treating aramid fiber with LiCl-polyvinylpyrrolidone solution and then grafting aramid fiber with a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate.

[0062] The modified aramid fiber is prepared as follows: LiCl and polyvinylpyrrolidone are weighed and dissolved in 3-5 times the volume of ethanol solution, and heated until completely dissolved to obtain a uniform and transparent LiCl-polyvinylpyrrolidone solution. Then, the aramid fiber is immersed in the LiCl-polyvinylpyrrolidone solution and stirred at a constant temperature for 2-4 hours to ensure full wetting of the fiber and effective adhesion of LiCl-polyvinylpyrrolidone to the surface of the aramid fiber, keeping the surface moist. Next, the aramid fiber is immersed in a toluene solution of trimethoxysilane / 1,6-hexamethylenediisocyanate and sonicated for 25 minutes. Then, it is placed in a 90℃ oven for 1 hour and then in a 140℃ oven for 4 hours to allow the toluene to evaporate completely. Finally, it is removed, soaked in deionized water at 100℃ for 1 hour, and dried to obtain the modified aramid fiber.

[0063] The inner and outer sheaths, by weight, comprise the following raw materials: 90 parts styrene-butadiene rubber, 12 parts nano-silica, 26 parts polyvinyl chloride, 3 parts calcium carbonate, 1.5 parts 2,6-di-tert-butyl-4-methylphenol, 0.8 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl,4-hydroxyphenyl)propionate], 0.8 parts benzotriazole UV absorber, 4 parts organosilicon hydrophobic agent, 7 parts expanded graphite, 0.8 parts silane coupling agent, and 2 parts polyethylene wax.

[0064] This application also provides a method for fabricating an ultra-flexible cable for humanoid robots, comprising the following steps:

[0065] S1: Using a coating machine, copper foil wires are spirally wound around an aramid fiber column, and then several copper foil wires are twisted in layers to form a conductor;

[0066] S2: Weigh out styrene-butadiene rubber, high styrene, stearic acid, aramid fiber, silica, accelerator, zinc oxide, antioxidant, paraffin wax, and aromatic oil in proportion and mix them to obtain a mixture. Extrude the mixture into an insulating layer and coat it onto the conductor to form an insulating core.

[0067] S3: Several insulating cores are twisted together to form a cable core wire;

[0068] S4: Weigh out 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 UV absorber, organosilicon hydrophobic agent, expanded graphite, silane coupling agent, and polyethylene wax in proportion to make an inner sheath.

[0069] S5: Wrap the inner sheath around the outer layer of the cable core, and then wrap the shielding layer and the outer sheath in sequence to obtain the ultra-flexible cable for humanoid robots.

[0070] Example 2

[0071] 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.

[0072] Example 3

[0073] 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.

[0074] Example 4

[0075] 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.

[0076] Example 5

[0077] This embodiment is basically the same as Example 1, except that in the preparation method of modified aramid fiber, the aramid fiber is immersed in a toluene solution of trimethoxysilane / 1,6-hexamethylenediisocyanate and sonicated for 20 min; then placed in an oven at 100℃ for 1.5 h and in an oven at 130℃ for 5 h to allow the toluene to evaporate completely.

[0078] Example 6

[0079] This embodiment is basically the same as Example 1, except that in the preparation method of modified aramid fiber, the aramid fiber is immersed in a toluene solution of trimethoxysilane / 1,6-hexamethylenediisocyanate and sonicated for 30 min; then placed in a 95℃ oven for 1 h and in a 150℃ oven for 3 h to allow the toluene to evaporate completely.

[0080] Example 7

[0081] This embodiment is basically the same as Embodiment 1, except that the raw materials of the inner and outer sheaths are 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 organosilicon hydrophobic agent, 8 parts of expanded graphite, 1 part of silane coupling agent, and 4 parts of polyethylene wax.

[0082] Example 8

[0083] This embodiment is basically the same as Embodiment 1, except that the raw materials of the inner and outer sheaths are 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 organosilicon hydrophobic agent, 5 parts of expanded graphite, 0.5 parts of silane coupling agent, and 2 parts of polyethylene wax.

[0084] Comparative Example 1

[0085] This comparative example is basically the same as Example 1, except that aramid fiber pillars are not provided in the conductor.

[0086] Comparative Example 2

[0087] This comparative example is basically the same as Example 1, except that the copper foil wire is not a spiral structure.

[0088] Comparative Example 3

[0089] This comparative example is basically the same as Example 1, except that the aramid fibers in the insulating layer are not modified.

[0090] Performance testing

[0091] The impact strength of the cables in Examples 1-8 and Comparative Examples 1-3 was tested according to standard GB / T1451-2005 "Test Method for Impact Toughness of Fiber Reinforced Plastics in Simply Supported Beams" and the tensile strength of the cables in Examples 1-8 and Comparative Examples 1-3 was tested according to GB / T2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Wires". The flexibility of the cables in Examples 1-8 and Comparative Examples 1-3 was tested according to standard GB / T 238-2013 "Metallic Wires - Repeated Bending Test Method". Bending force was applied at a uniform speed of 1-2 times / second for 30 minutes, and the appearance of creases was observed. The results are shown in Table 1.

[0092]

[0093] As shown in the table above, embodiments 1-8 of my invention utilize a spiral structure of copper foil wire with embedded aramid fiber pillars to form the conductor. Aramid fibers themselves possess high modulus and high strength; embedding them in copper foil wire significantly improves the conductor's tensile strength. Furthermore, the spiral structure of the copper foil wire, combined with the flexibility of the aramid fibers, allows the copper foil wire to be repeatedly bent in complex wiring environments without easily breaking or deforming. The modified aramid fibers in the insulation layer of this invention are treated with a LiCl-polyvinylpyrrolidone solution. The arrangement of the aramid molecular chains is adjusted through ionic interactions, thereby improving the tensile and shear strength of the modified aramid fibers. Polyvinylpyrrolidone can improve the dispersibility of LiCl, resulting in a more uniform increase in the strength of the aramid fibers. This invention uses a toluene solution of trimethoxysilane / 1,6-hexamethylene diisocyanate to graft aramid fibers. The grafted aramid fibers bond more tightly with other materials in the insulation layer, effectively improving the overall flexibility, durability, and anti-aging properties of the cable.

[0094] As can be seen from Comparative Example 1, when aramid fiber pillars are 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 also worse. As can be seen from Comparative Example 2, when the copper foil wire adopts a common structure and does not adopt a spiral structure, the tensile strength and impact strength of the cable are reduced. As can be seen from Comparative Example 3, when the aramid fibers in the insulation layer are not modified, the tensile strength and impact strength of the cable are reduced compared to those with modified aramid fibers.

[0095] In summary, the cable of this invention has excellent flexibility and is suitable for various complex and confined installation spaces and applications involving frequent bending. The addition of modified aramid fibers and the optimized cabling structure significantly improve the cable's tensile strength and bending fatigue resistance, extending its service life. The shielding layer woven from conductive yarns ensures stable signal transmission and effectively resists electromagnetic interference.

[0096] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. An ultra-flexible cable for a humanoid robot, comprising a core, an insulating layer, and a sheath, characterized in that, The core comprises copper foil filaments and aramid fiber columns, and the copper foil filaments are spirally twisted around the aramid fiber columns; the aramid fiber columns are further provided with a protective coating composed of nano-silicon dioxide and fluorocarbon resin; The insulating layer comprises the following raw materials in parts by weight: styrene-butadiene rubber 25-35 parts, high styrene 15-30 parts, stearic acid 16-22 parts, modified aramid fiber 5-8 parts, white carbon black 3-5 parts, accelerator 3-8 parts, zinc oxide 2-7 parts, antioxidant 3-6 parts, paraffin 1-5 parts, and aromatic oil 1-5 parts; The preparation raw material of the insulating layer comprises modified aramid fiber, which is obtained by treating aramid fiber with a LiCl-polyvinylpyrrolidone solution and then grafting the aramid fiber with a trimethoxysilane / 1,6-hexane diisocyanate toluene solution; the mass fraction of LiCl in the LiCl-polyvinylpyrrolidone solution is 35-42%.

2. The super flexible cable for humanoid robots according to claim 1, characterized in that, The aramid fiber column comprises a plurality of aramid fibers with a fineness of 1000 d or more.

3. The super flexible cable for humanoid robots according to claim 1, characterized in that, The copper foil filaments have 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°.

4. The super flexible cable for humanoid robots according to claim 1, characterized in that, The core is arranged in a cabling structure layer, and the sheath is arranged outside the cabling structure, and the cabling structure is filled with a plurality of aramid fiber columns.

5. The super flexible cable for humanoid robots according to claim 1, characterized in that, The sheath comprises an inner sheath, a shielding layer and an outer sheath, and the shielding layer comprises electrically conductive yarns woven by copper fibers and aramid fibers, wherein the mass fraction of the copper fibers is 55-60 parts, and the mass fraction of the aramid fibers is 40-45 parts.

6. The super flexible cable for humanoid robots according to claim 5, characterized in that, The inner sheath and the outer sheath comprise the following raw materials in parts by weight: styrene-butadiene rubber 80-100 parts, nano-silicon dioxide 10-15 parts, polyvinyl chloride 20-30 parts, calcium carbonate 1-5 parts, 2,6-di-tert-butyl-4-methylphenol 1-2 parts, tetra[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionic acid] pentaerythritol ester 0.5-1 part, benzotriazole ultraviolet absorber 0.5-1 part, silicone hydrophobic agent 3-5 parts, expanded graphite 5-8 parts, silane coupling agent 0.5-1 part, and polyethylene wax 1-5 parts.

7. The super flexible cable for humanoid robots according to claim 5, characterized in that, 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.

8. A method of producing the super flexible cable for humanoid robots according to any one of claims 1 to 7, characterized by, The method comprises the following steps: S1: spirally winding copper foil filaments around aramid fiber columns using a wrapping machine, and then layer-twisting the copper foil filaments to form a conductor; S2: mixing and kneading styrene-butadiene rubber, high styrene, stearic acid, aramid fiber, white carbon black, accelerator, zinc oxide, antioxidant, paraffin and aromatic oil to obtain a mixture, and then extruding the mixture to form an insulating layer wrapped around the conductor to form an insulating core; S3: layer-twisting a plurality of the insulating cores to form a cabling core; S4: mixing and kneading styrene-butadiene rubber, nano-silicon dioxide, polyvinyl chloride, calcium carbonate, 2,6-di-tert-butyl-4-methylphenol, tetra[β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionic acid] pentaerythritol ester, benzotriazole ultraviolet absorber, silicone hydrophobic agent, expanded graphite, silane coupling agent and polyethylene wax to obtain an inner sheath and an outer sheath. S5: The inner sheath is wrapped on the outer layer of the cabling core wire, and then the shielding layer and the outer sheath are sequentially wrapped, so as to obtain the super-flexible cable for humanoid robots.

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