High-elasticity stamping-resistant leaky coaxial cable

Abstract

The utility model relates to the technical field of communication transmission cables, in particular to a high-elasticity stamping-resistant leaky coaxial cable, which sequentially comprises an inner conductor, an outer conductor, an outer conductor and an outer conductor from inside to outside, the inner conductor is a steel wire, and the surface of the steel wire is plated with copper; the foaming insulating layer is coated on the outer surface of the inner conductor; the outer conductor is coated on the outer surface of the foaming insulating layer; the sheath layer coats the outer surface of the composite outer conductor; the foaming insulating layer comprises a foaming layer and an outer skin layer, the foaming layer is made of a modified polyurethane material, the outer skin layer is made of solid high-density polyethylene, and the thickness of the outer skin layer ranges from 0.05 mm to 0.1 mm. The insulating layer provided by the utility model is made of high-elasticity modified polyurethane foam, the inner conductor and the outer conductor are mainly made of high-elasticity copper-plated steel wires, and the selected materials have high recovery capability after being pressed, so that the high-frequency signal transmission capability of the radio-frequency coaxial cable in complex environments such as mines, industrial sites, rescue and relief work and the like is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of communication transmission cables, in particular to a high-elasticity, punching-resistant and leaky coaxial cable. Background Art

[0002] As the main medium for communication transmission, leaky coaxial cable has the functions of both signal transmission line and transceiver antenna, and has the advantages of high reliability and stability. However, in order to ensure high-frequency performance of communication, the insulation layer of conventional leaky coaxial cable adopts hard polyethylene foam material, which will cause insulation collapse after being squeezed by external force; and the inner and outer conductor materials are mainly soft copper materials. After being squeezed by a large external force, the whole cannot return to its original state, and it is difficult to adapt to complex scenarios such as mines, industrial sites, and communication transmission in disaster relief. Therefore, there is an urgent need to improve the materials and structures of existing leaky coaxial cables.

[0003] The insulating layer of this application adopts modified polyurethane foam with high elasticity, and the inner conductor is mainly made of high-elastic copper-plated steel wire. The selected materials have high recovery ability after pressure, thus greatly improving the high-frequency signal transmission capability of the RF coaxial cable in complex environments such as mines, industrial sites, emergency rescue, etc.

[0004] The published patent technologies related to this utility model are as follows:

[0005] The Chinese patent with publication number CN113284651A discloses a flexible pressure-resistant coaxial cable and its preparation method, which includes an inner conductor formed by twisting multiple strands of tinned copper wires, an insulating layer coated on the outside of the inner conductor, an outer conductor coated on the outside of the insulating layer, and an outer sheath coated on the outside of the outer conductor. The insulating layer includes, from the inside to the outside, a soft polyvinyl chloride layer, an impact-resistant buffer layer, and a soft polyvinyl chloride layer; the impact-resistant buffer layer is a dilatant gel; the dilatant gel raw materials include amphiphilic styrene particles, grafted carboxymethyl, sodium cellulose, and ethylene glycol; through the combination of the above structure and materials, the obtained cable can still maintain stable operation after multiple cycles of impact and bending, and the impact resistance of the cable is not affected even if it is left stationary for a long time. The preparation method is simple and has good universality, which is very conducive to promotion.

[0006] The insulating layer of this patent mainly adopts: soft polyvinyl chloride layer, impact-resistant buffer layer and soft polyvinyl chloride layer. However, since polyvinyl chloride material is a polar material with a large dielectric constant, especially when it is not foamed, its high-frequency communication performance is poor. It is generally only used for the insulation structure of digital symmetrical cables and control cables, and it is difficult to meet the current application of RF coaxial cables with high frequencies above 3GHz.

[0007] A Chinese patent with announcement number CN209388740U discloses a flexible cable for a robot, including a thin cable core, a thin copper wire is arranged at the center of the cable core, a polyurethane insulation layer is arranged on the outside of the thin copper wire, a sheath layer is arranged on the outside of the polyurethane insulation layer, a flexible braided mesh is arranged on the surface of the sheath layer, a thermoplastic rubber layer is arranged on the outside of the flexible braided mesh, a silicone layer is arranged on the outside of a polypropylene filler, a filling rope is arranged on the surface of the silicone layer, and polyvinyl chloride is arranged on the outside of the filling rope.

[0008] This patented product is a feeder cable, whose insulation layer is made of polyurethane material, which only utilizes the high elastic recovery ability of the material itself. It is only similar in structure to the present application, but because it does not involve high-frequency communication applications, it does not consider how to modify the polyurethane and how to reduce the dielectric constant of the material.

[0009] The Chinese patent with the announcement number CN115368725B discloses a high dielectric constant and low dielectric loss thermoplastic polyurethane elastomer composite material and its preparation method, comprising 100 parts by weight of thermoplastic polyurethane elastomer, 0.1 to 100 parts by weight of layered compound formed by self-assembly of conductive filler with negative surface potential and inorganic filler with positive surface potential and high temperature reaction, and / or 0.1 to 100 parts by weight of layered compound formed by self-assembly of conductive filler with positive surface potential and inorganic filler with negative surface potential and high temperature reaction. The thermoplastic polyurethane composite material has high dielectric constant and low dielectric loss, and the product can be used in the fields of cables, capacitors, transducers, filters, etc.

[0010] This patented product is a modification method for thermoplastic polyurethane materials, which only considers how to reduce dielectric loss, but at the same time improves the dielectric constant of the material. Low dielectric loss means that the material has less energy loss under the action of the electric field, which is conducive to high-frequency communication, but high dielectric constant materials mean that the material has a strong response ability to the electric field, but it is also easy to cause signal scattering and diffraction, increasing the propagation loss of the signal. Utility Model Content

[0011] The technical problem to be solved by the utility model is: in order to solve the technical problem that conventional leaky coaxial cables are prone to communication failures after being deformed by external pressure, the utility model provides an insulating layer using modified polyurethane foam with high elasticity, and the inner and outer conductors are mainly made of high-elastic copper-plated steel wire. The selected materials all have high recovery ability after being compressed, thereby greatly improving the high-frequency signal transmission capability of the radio frequency coaxial cable in complex environments such as mines, industrial sites, emergency rescue and disaster relief.

[0012] The utility model solves the technical problem by adopting the following technical solution: a high-elasticity, stamping-resistant and leaky coaxial cable, which comprises, from inside to outside, an inner conductor, which is a steel wire, and the surface of the steel wire is copper-plated; a foamed insulation layer, which is coated on the outer surface of the inner conductor; an outer conductor, which is coated on the outer surface of the foamed insulation layer; and a sheath layer, which is coated on the outer surface of the outer conductor; wherein the foamed insulation layer comprises a foamed layer and an outer skin layer, the foamed layer is a modified polyurethane material, the outer skin layer is solid high-density polyethylene, and the thickness of the outer skin layer ranges from 0.05 mm to 0.1 mm.

[0013] Furthermore, the thickness of the outer skin layer ranges from 0.05 mm to 0.1 mm.

[0014] Furthermore, the steel wire is made of high-elastic carbon steel, and a copper plating layer is provided on the surface of the steel wire, and the copper plating layer is made of cathode copper.

[0015] Furthermore, the thickness of the copper plating layer ranges from 0.1 mm to 0.2 mm.

[0016] Furthermore, the modified polyurethane material of the foaming layer is a thermoplastic polyurethane material that is modified and filled with ultra-low dielectric nanoporous cage-type silsesquioxane, which is fused with high-density polyethylene to form a copolymer, and is physically foamed by injecting CO2 or N2.

[0017] Furthermore, the outer conductor is made of a copper-plastic composite film, and the copper-plastic composite film is punched with periodic slots.

[0018] Furthermore, the copper-plastic composite film comprises a copper layer and a plastic layer, the copper layer has a thickness ranging from 0.1 mm to 0.2 mm, and the plastic layer has a thickness ranging from 0.08 mm to 0.2 mm.

[0019] Furthermore, the plastic layer is arranged outside the copper layer.

[0020] Furthermore, the sheath layer is made of cross-linked polyolefin or rubber material.

[0021] The beneficial effects of the utility model are:

[0022] 1. Both the inner and outer conductors are made of highly elastic materials and structures, which can improve the ability of the RF coaxial cable to recover to its original shape after being deformed by extrusion, impact, etc., and is more suitable for high-frequency signal transmission in complex environments such as mines, industrial sites, and disaster relief.

[0023] 2. The product structure is more reasonable and scientific: using high-elastic copper-plated steel wire as the inner conductor, copper-plastic composite film and high-elastic copper-plated steel wire braided composite outer conductor, can not affect the high-frequency communication performance of the cable, while improving the product's extrusion and impact capabilities.

[0024] 3. The modified thermoplastic polyurethane with physical foaming structure is used as the insulating layer, which has high elastic recovery ability and can quickly return to its original state after being squeezed or impacted, ensuring smooth communication and improving the product's high-frequency signal transmission capability in complex environments.

[0025] 4. The outer conductor adopts copper-plastic composite film, which can realize the function of the outer conductor of the RF coaxial cable while providing structural support for the cable, ensuring the recovery ability of the outer conductor after being squeezed and impacted. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0027] Figure 1 It is a schematic longitudinal section diagram of a high-elasticity, stamping-resistant radio frequency coaxial cable in the utility model.

[0028] Figure 2 It is a schematic diagram of the cross section of the high elasticity and stamping resistant radio frequency coaxial cable in the utility model.

[0029] In the figure: 1, inner conductor; 2, foamed insulation layer; 21, foamed layer; 22, outer skin layer; 3, outer conductor; 31, copper-plastic composite film; 311, periodic slots; 4, sheath layer. DETAILED DESCRIPTION

[0030] Now the utility model is further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the components related to the utility model.

[0031] In the description of the present utility model, it is necessary to understand that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] The utility model discloses a high-elasticity, punching-resistant and leaking coaxial cable.

[0033] Reference Figure 1 and Figure 2 A high elastic stamping resistant leakage coaxial cable is sequentially arranged from the inside to the outside as follows: an inner conductor 1, a foamed insulation layer 2, an outer conductor 3 and a sheath layer 4. The inner conductor 1 is made of a high elastic copper-plated steel wire, the insulation layer is made of a modified polyurethane with a physical foaming structure, the outer conductor 3 is made of a copper-plastic composite film 31, and the sheath layer 4 is made of a cross-linked polyolefin or rubber.

[0034] The material of the inner conductor 1 is a high-elastic copper-plated steel wire, and the steel wire is a high-elastic carbon steel with a grade of 65 or 70; the surface coating of the steel wire is cathode copper, and the thickness of the copper coating ranges from 0.1mm to 0.2mm. The purpose of using high-elastic carbon steel is to improve the elasticity of the inner conductor 1, so that the cable can be restored to its original state when it is subjected to external forces such as extrusion, bending and deformation. The surface coating of the steel wire is cathode copper, and the thickness of the copper coating ranges from 0.1mm to 0.2mm, in order to ensure the high-frequency electromagnetic field signal transmission performance of the cable.

[0035] The skin depth calculation formula according to the high-frequency electromagnetic field transmitted in the metal conductor is:

[0036]

[0037] in:

[0038] δ——skin depth, unit: m;

[0039] ω——angular frequency, ω=2πf, unit: rad / s, where f is the electromagnetic field frequency, unit: Hz

[0040] μ——magnetic permeability, unit: H / m;

[0041] ρ——resistivity, unit: Ω·M;

[0042] The calculation can be obtained:

[0043] Table 1. Skin depth of high frequency electromagnetic field transmission in metal conductors

[0044]

[0045]

[0046] Therefore, the copper layer thickness of the highly elastic copper-plated steel wire as the inner conductor 1 can meet the communication requirements under high frequency, and can replace the traditional copper wire or copper-clad aluminum wire as the inner conductor 1 of the cable without affecting the high-frequency electrical performance of the cable.

[0047] The material of the foamed insulating layer 2 is a copolymer of modified polyurethane and polyethylene. The modified polyurethane is a thermoplastic polyurethane in which a certain proportion of ultra-low dielectric nanoporous cage-type silsesquioxane (POSS) is added for physical blending and filling modification to reduce the dielectric constant of the polyurethane.

[0048] Since polyurethane is a polymer material made by polycondensation of isocyanate and polyol, the amino and hydroxyl groups in its molecules are polar groups, and the oxygen atoms on the polyurethane chain are highly electrophilic, which makes polyurethane have strong molecular polarity, resulting in poor dielectric properties of polyurethane, especially excessive high-frequency dielectric loss in communication transmission, which limits its application as a communication transmission medium insulation layer. The method of introducing ultra-low dielectric nanoporous cage-type silsesquioxane (POSS) for physical blending filling modification uses the weak dipole moment of the si-o bond to reduce the dielectric constant of the polyurethane material, and uses the dielectric confinement effect of the POSS nanoparticles themselves to generate a strong self-polarization induction effect at the polyurethane heterogeneous medium in contact with the phase, so that the electron cloud at the heterogeneous medium is radially localized, and the polarization of its electron cloud is limited, so that the dielectric constant of the material can be significantly reduced, and the high-frequency communication performance of the coaxial cable is improved.

[0049] At the same time, ultra-low dielectric nanoporous cage silsesquioxane (POSS) can be used as a foaming nucleating agent for polyurethane to improve the foaming degree of polyurethane. Before filling and modification, nano polyhedral cage silsesquioxane (POSS) needs to be treated with silane coupling agent or other suitable coupling agent. The coupling agent can enhance the interaction between two molecules of different polarity, act as a chemical medium, increase the bonding force between composite materials, and ensure that it is fully and evenly mixed with polyurethane materials.

[0050] The mixing method is physical blending, which is achieved by combining two or more methods of mechanical mixing, air flow pulverization and ultrasonic treatment to achieve full and uniform mixing.

[0051] Adding high-density polyethylene to modified polyurethane, high-density polyethylene has excellent dielectric properties, and its dielectric constant and dielectric loss are almost independent of temperature and frequency; especially good high-frequency performance, suitable for manufacturing the insulation layer of various high-frequency cables, mainly used in this application to support the pore structure, ensure the mechanical strength of the insulation layer, and enhance the closure of the foamed pores, prevent moisture from invading the insulation pores, play a role in longitudinal water blocking, and improve the application of cables in humid environments. Add a small amount of azodicarbonamide to high-density polyethylene as a nucleating agent.

[0052] The main components of the insulating mixed material are as follows: 60% to 70% polyurethane, 10% to 15% ultra-low dielectric nanoporous cage-type silsesquioxane (POSS), 25% to 30% linear high-density polyethylene, and 0.1% to 0.5% azodicarbonamide.

[0053] The use of polyurethane material is due to its high elasticity, and the purpose of adding polyethylene is to reduce the dielectric constant of the overall insulation layer. The dielectric constant of the insulation layer is related to the signal attenuation of the RF coaxial cable in high-frequency electromagnetic field communication. At the same time, in order to reduce the dielectric constant of the insulation layer. The method of injecting CO2 or N2 gas into the molten modified polyurethane material is used for physical foaming to further reduce the material density in the insulation layer. In theory, the transmission attenuation of high-frequency electromagnetic fields in a vacuum is the lowest. Therefore, the dielectric constant of the insulation layer can be comprehensively reduced by physical foaming. At the same time, adding polyethylene to polyurethane can improve the stability of the pore structure of the insulation layer, which is beneficial to the integrity of the pore structure of the insulation layer while maximizing the foaming degree, and prevent the collapse of the pore structure of the insulation layer due to excessive foaming.

[0054] The foamed insulating layer 2 includes a foamed layer 21 and an outer skin layer 22. The foamed layer 21 is a modified polyurethane material, and the outer skin layer 22 is a solid high-density polyethylene. The purpose of adding the outer skin layer 22 is to help wrap the foamed layer 21 inside, and prevent water vapor and moisture from invading the inside of the insulating layer during production and use. The thickness of the outer skin layer 22 ranges from 0.05mm to 0.1mm.

[0055] Table 2. Main properties of related materials

[0056]

[0057] The outer conductor 3 is composed of a copper-plastic composite film 31 and periodic slots 311 punched on the copper-plastic composite film. The copper-plastic composite film 31 is longitudinally wrapped on the foamed insulating layer 2. Since the copper-plastic composite film 31 is flexible, it can quickly recover to its normal size under the support of the high elastic insulating layer after being squeezed by external force, thereby improving the compressive recovery ability of the RF coaxial cable. The copper-plastic composite film 31 includes a copper layer and a plastic layer, the thickness of the copper layer ranges from 0.1mm to 0.2mm, and the thickness of the plastic layer ranges from 0.08mm to 0.2mm. The copper-plastic composite film is punched with periodic slots 311 for signal radiation and reception of the leaky coaxial cable.

[0058] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without deviating from the technical concept of the utility model through the above description. The technical scope of the utility model is not limited to the content of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A high elasticity punching resistant leakage coaxial cable, characterized in that: From inside to outside, it includes: An inner conductor (1), the inner conductor (1) being a steel wire, the surface of the steel wire being copper-plated; A foamed insulating layer (2) covering the outer surface of the inner conductor (1); An outer conductor (3) coated on the outer surface of the foamed insulating layer (2); A sheath layer (4) covering the outer surface of the outer conductor (3); The foamed insulating layer (2) comprises a foamed layer (21) and an outer skin layer (22); the foamed layer (21) is a modified polyurethane material, and the outer skin layer (22) is a solid high-density polyethylene.

2. The high elasticity and pressure resistant leaky coaxial cable according to claim 1, characterized in that: The thickness of the outer skin layer (22) ranges from 0.05 mm to 0.1 mm.

3. The high elasticity and pressure resistant leaky coaxial cable according to claim 1, characterized in that: The steel wire is made of high-elastic carbon steel, and a copper plating layer is provided on the surface of the steel wire, and the copper plating layer is made of cathode copper.

4. The high elasticity and punch-resistant leakage coaxial cable according to claim 3, characterized in that: The thickness of the copper plating layer ranges from 0.1 mm to 0.2 mm.

5. The high elasticity and pressure resistant leaky coaxial cable according to claim 3, characterized in that: The modified polyurethane material of the foaming layer (21) is a thermoplastic polyurethane material in which ultra-low dielectric nanoporous cage-type silsesquioxane is introduced for modification and filling, which is then fused with high-density polyethylene to form a copolymer, and a physical foaming method is adopted by injecting CO2 or N2.

6. The high elasticity and pressure resistant leaky coaxial cable according to claim 5, characterized in that: The outer conductor (3) is made of a copper-plastic composite film (31), and the copper-plastic composite film (31) is punched with periodic slots (311).

7. The high elasticity and pressure resistant leaky coaxial cable according to claim 6, characterized in that: The copper-plastic composite film (31) comprises a copper layer and a plastic layer, the thickness of the copper layer ranges from 0.1 mm to 0.2 mm, and the thickness of the plastic layer ranges from 0.08 mm to 0.2 mm.

8. The high elasticity and pressure resistant leaky coaxial cable according to claim 7, characterized in that: The plastic layer is arranged outside the copper layer.

9. The high elasticity and punch-resistant leaky coaxial cable according to claim 1, characterized in that: The sheath layer (4) is made of cross-linked polyolefin or rubber material.

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