Ethernet high-efficiency shielding low-loss high-frequency transmission cable

Abstract

The utility model discloses an Ethernet high-efficiency shielding low-loss high-frequency transmission cable, which comprises a cable core, the cable core comprises a plurality of oxygen-free copper cores, the outer side of the plurality of oxygen-free copper cores is coated with a dielectric insulating layer, and the outer side of the dielectric insulating layer is sequentially coated with an aluminum foil shielding layer, a metal wire braided shielding enhancement layer and a plastic outer sheath. And the dielectric insulating layer is a supercritical fluid micro-closed cell foaming material formed by adding nitrogen or carbon dioxide into a polymer dielectric material. By means of the mode, the requirements of the Ethernet in the automobile industry on the aspects of electromagnetic compatibility, high reliability, low electromagnetic radiation, low power consumption, bandwidth distribution, low delay, synchronous real-time performance and the like can be met, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of cables, and in particular to an Ethernet high-efficiency shielding low-loss high-frequency transmission cable. Background Art

[0002] Automotive Ethernet technology is a new local area network technology for connecting different in-vehicle automotive electronic devices.

[0003] Automotive Ethernet technology is based on the Ethernet standard. Compared with traditional Ethernet, it uses single-pair unshielded twisted-pair electricity to achieve transmission rates of up to 100 megabits per second, gigabits per second (G / s), or even 10 gigabits per second (10G / s). This technology not only meets the requirements of the automotive industry for high reliability, low electromagnetic radiation, low power consumption, bandwidth allocation, low latency, and synchronous real-time performance, but also provides a high-bandwidth solution at low cost.

[0004] Automotive Ethernet will play a very important role in the development of the new four modernizations of automobiles. In the field of information technology and industry, the development of multifunctional, high-performance, and thin-and-light microelectronic products has greatly promoted the development of key technologies and materials for ultra-high density and very large scale integrated circuits. To solve problems such as signal delay and power loss caused by high-density integration, the development of a new generation of high-performance low-dielectric or even ultra-low-dielectric microcellular foamed materials has become one of the most important research directions in this field.

[0005] The Ethernet transmission technology for automotive intelligent driving is being increasingly widely used in the automotive field. It plays an important role in in-vehicle multimedia, vehicle diagnosis and maintenance, safety and driver assistance systems, in-vehicle communication, and remote vehicle control. It can transmit data from cameras, radars, and other sensors to support driver assistance functions such as adaptive cruise control and automatic braking systems. Ethernet can also connect the communication between vehicles and traffic infrastructure to provide real-time traffic conditions and navigation information.

[0006] Ordinary network cables extrude a dense material layer such as PE, HDPE, or PVC continuously on the conductor as the insulating layer. The dielectric constant of the dense material insulating layer is large, resulting in large signal loss and distortion in the high-frequency and high-speed signal transmission of intelligent driving safety and assistance systems. The material microstructure of the original transmission line with a dense insulating layer can no longer meet the new requirements of automotive Ethernet transmission for current automotive intelligent driving. Summary of the Invention

[0007] The main technical problem to be solved by the present invention is to provide an Ethernet high-efficiency shielded low-loss high-frequency transmission cable, which prevents the contact oxidation of oxygen in the air with the surface of the multi-strand oxygen-free copper core through a dielectric insulation layer, greatly reduces the dielectric constant of the transmission line and the loss of the copper oxide film on the surface of the copper conductor, and can meet the requirements of the automotive industry's Ethernet for electromagnetic compatibility characteristics, high reliability, low electromagnetic radiation, low power consumption, bandwidth allocation, low latency, and synchronous real-time performance, etc., and reduces the production cost.

[0008] To solve the above technical problems, a technical solution adopted by the present invention is: to provide an Ethernet high-efficiency shielded low-loss high-frequency transmission cable, including a core wire, the core wire includes a multi-strand oxygen-free copper core, and the outside of the multi-strand oxygen-free copper core is coated with a dielectric insulation layer. An aluminum foil shielding layer, a metal wire braided shielding reinforcement layer, and a plastic outer sheath are sequentially coated on the outside of the dielectric insulation layer. The dielectric insulation layer is a supercritical fluid micro-closed cell foaming material formed by adding nitrogen or carbon dioxide to a high molecular dielectric material.

[0009] In a preferred embodiment of the present invention, the aluminum foil shielding layer is an aluminum foil semi-overlapping winding layer with a thickness of 63-72 μm.

[0010] In a preferred embodiment of the present invention, the metal wire braided shielding reinforcement layer is a mesh braided layer formed by braiding aluminum-magnesium wire, red copper, and tinned copper wire.

[0011] In a preferred embodiment of the present invention, the high molecular dielectric material is thermoplastic polyurethane rubber, block polyether amide resin, ethylene-vinyl acetate copolymer, or thermoplastic elastomer.

[0012] In a preferred embodiment of the present invention, the plastic outer sheath is a polyvinyl chloride sheath, a polyethylene sheath, a thermoplastic polyurethane sheath, or a low-smoke halogen-free sheath.

[0013] In a preferred embodiment of the present invention, two core wires form a cross twisted pair.

[0014] The beneficial effects of the present invention are: the Ethernet high-efficiency shielded low-loss high-frequency transmission cable of the present invention adds nitrogen or carbon dioxide to thermoplastic polyurethane rubber, block polyether amide resin, ethylene-vinyl acetate copolymer, or thermoplastic elastomer to form a supercritical fluid micro-closed cell foaming material. The outer surface of the multi-strand oxygen-free copper core conductor is wrapped with a continuously extruded supercritical fluid micro-closed cell foaming material, which prevents the contact oxidation of oxygen in the air with the surface of the multi-strand oxygen-free copper core, greatly reduces the dielectric constant of the transmission line and the loss of the copper oxide film on the surface of the copper conductor, and realizes a transmission rate of 100 megabits, 1 gigabit, or even 10 gigabits.

[0015] The high-efficiency shielded low-loss high-frequency transmission cable for Ethernet of the present invention achieves a more complete shielding effect against radio frequency (RFI) high-frequency interference through a semi-overlapping winding layer with a thickness of 63-72 μm. Moreover, the thickness of the aluminum foil can withstand greater destructive forces. Thus, it can provide users with higher-quality transmission performance.

[0016] For the high-efficiency shielded low-loss high-frequency transmission cable for Ethernet of the present invention, the mesh braided layer functions to shield electromagnetic low-frequency interference, and its outer sheath is made of a flexible plastic material to meet the engineering requirements under different environmental conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, where:

[0018] Figure 1 is a schematic structural diagram of the high-efficiency shielded low-loss high-frequency transmission cable for Ethernet of the present invention;

[0019] Figure 2 is a schematic diagram of the principle for preparing the supercritical fluid micro-closed cell foaming material;

[0020] The labels of the components in the drawings are as follows: 1, oxygen-free copper core; 2, dielectric insulation layer; 3, aluminum foil shielding layer; 4, metal wire braided shielding reinforcement layer; 5, plastic outer sheath. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limited conditions for the implementation of the present invention. Therefore, they do not have a substantial technical meaning. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of clear narration and are not used to limit the scope of implementation. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0022] Please refer to Figure 1 and Figure 2, An Ethernet high-efficiency shielded low-loss high-frequency transmission cable, comprising a core, the core including a plurality of oxygen-free copper cores 1, and an outer side of the plurality of oxygen-free copper cores 1 is coated with a dielectric insulation layer 2. Two cores form a cross twisted pair.

[0023] The dielectric insulation layer 2 is a supercritical fluid micro-closed cell foaming material formed by adding nitrogen or carbon dioxide to a polymer dielectric material. The polymer dielectric material is a material such as thermoplastic polyurethane rubber, block polyether amide resin, ethylene-vinyl acetate copolymer or thermoplastic elastomer.

[0024] Since air has an extremely low dielectric constant (k = 1), nitrogen or carbon dioxide is added to general polymer dielectric materials such as thermoplastic polyurethane rubber TPU, block polyether amide resin PEBAX, ethylene-vinyl acetate copolymer EVA, thermoplastic elastomer TPE to form a supercritical fluid micro-closed cell foaming material. The outer surface of the multi-strand oxygen-free copper core 1 conductor is wrapped with a continuously extruded supercritical fluid micro-closed cell foaming material such as TPU, PEBAX, EVA, TPE, eliminating the contact oxidation of oxygen in the air with the surface of the multi-strand oxygen-free copper core 1, greatly reducing the dielectric constant of the transmission line and the loss of the copper oxide film on the surface of the copper conductor. Transmission rates of up to 100 megabits, gigabits (G / s) or even 10 gigabits (10 G / s) are achieved.

[0025] An outer side of the dielectric insulation layer 2 is sequentially coated with an aluminum foil shielding layer 3, a metal wire braided shielding reinforcement layer 4 and a plastic outer sheath 5. The aluminum foil shielding layer 3 is an aluminum foil semi-overlapped winding layer with a thickness of 63 - 72 μm. The metal wire braided shielding reinforcement layer 4 is a mesh braided layer formed by braiding aluminum-magnesium wire, red copper or tinned copper wire. The plastic outer sheath 5 is a polyvinyl chloride sheath, a polyethylene sheath, a thermoplastic polyurethane sheath or a low-smoke halogen-free sheath. An aluminum foil semi-overlapped winding layer with a thickness of 63 - 72 μm is used to wrap the outer surface layer of the cross twisted pair, achieving a more complete shielding effect against radio frequency (RFI) high-frequency interference. And the thickness of the aluminum foil can withstand greater destructive forces. Thereby, higher-quality transmission performance can be provided to users. Then, a mesh braided layer of aluminum-magnesium wire or red copper or tinned copper wire is used to wrap the cross-twisted signal wires outside its aluminum foil shielding layer 3 to shield electromagnetic (EMI) low-frequency interference, and its outer sheath is made of a soft plastic material such as PVC (polyvinyl chloride), PE (polyethylene), TPU (thermoplastic polyurethane), LSZH (low-smoke halogen-free), meeting the engineering requirements under different environmental conditions. The technology of the present invention not only meets the requirements of the automotive industry Ethernet for electromagnetic compatibility (EMC) characteristics, high reliability, low electromagnetic radiation, low power consumption, bandwidth allocation, low latency and synchronous real-time performance, etc., but also provides a high-bandwidth solution at low cost.

[0026] A preparation method of an Ethernet high-efficiency shielded low-loss high-frequency transmission cable, comprising the following steps:

[0027] S1. Pour the polymer dielectric plastic particles into the hopper of the extruder, unwind the oxygen-free copper core wire, thread it through the rear of the extruder, and then lead it out to the rewinder.

[0028] S2. Melt the polymer dielectric plastic particles in the extruder, inject nitrogen or carbon dioxide supercritical fluid into a special mixing device, mix it evenly with the molten plastic to form a two-phase homogeneous system, extrude and wrap it on the surface of the oxygen-free copper core. The fluid is at 75 °C and the pressure is 8 MPa. The pressure and flow rate of the CO2 or N2 supercritical fluid can be adjusted. The bubble nucleation and growth of the plastic layer on the oxygen-free copper core occur. The oxygen-free copper core wire is kept at a constant temperature in the air duct until it is cooled (25 °C - 30 °C), and after the bubbles are shaped, it is wound up to obtain the wire core.

[0029] The principle of supercritical foaming technology: Supercritical foaming is a new physical foaming technology. In the preparation process, first, the supercritical fluid medium is injected into a special device to make the medium fully and evenly mix / diffuse with the molten raw material to form a single-phase mixed sol. Then, by changing the pressure, the medium precipitates to form a large number of bubble nuclei. In the subsequent cooling and shaping process, by adjusting and controlling parameters, the bubble nuclei inside the sol grow and take shape continuously, and finally, qualified microcellular foamed products are obtained.

[0030] The principle of supercritical fluid microcellular foaming is as follows: A liquid with both temperature and pressure above the critical point is called a supercritical fluid. A supercritical fluid is a structure between a liquid and a gas. It will fill the entire space like a gas, and its viscosity and diffusion coefficient are closer to those of a gas, but its density is similar to that of a liquid.

[0031] Its foaming process can be divided into 4 stages: 1. Let the supercritical fluid enter the polymer matrix and reach a saturated state to form a polymer / gas homogeneous system; 2. A sudden increase in temperature or a sudden decrease in pressure causes the gas in the homogeneous system to reach a supersaturated state, that is, a thermodynamically unstable state, thus causing bubble nucleation; 3. The gas rapidly diffuses into the bubble nuclei and the cell gradually grows; 4. Rapid cooling is carried out to complete the shaping of the cell structure, and popcorn is formed after this process.

[0032] Supercritical foaming technology generally uses CO2 or N2 as the physical foaming agent because CO2 and N2 have stable chemical properties, low prices, are non-toxic and harmless, and are more environmentally friendly.

[0033] The continuous extrusion method is to add the polymer into the extruder. After melting and homogenization, the gas is injected into the polymer melt through the main inlet of the barrel. The injected gas and the polymer melt are immediately mixed to form a gas-liquid two-phase mixture. Under the action of the shear mixing field in the barrel, the gas in the two-phase mixture completely diffuses into the polymer melt to form a polymer / gas homogeneous system. Finally, the homogeneous system is transported into the foaming head for microcellular foaming.

[0034] SCF (supercritical) microcellular foaming injection molding includes the following three special process steps: 1) Injecting supercritical fluid foaming agent, such as N2 or CO2, into the molten resin in the plasticizing device of the injection molding machine according to the required dosage and injection process; 2) Under a certain supercritical state, the injected N2 or CO2 is evenly dispersed in the molten resin to form a homogeneous solution, and maintained in a homogeneous solution state before injection; 3) Under appropriate mold conditions, bubbles nucleate and grow, and cool and shape to obtain microcellular foam products.

[0035] S3. The wire core is unwound to form a cross twisted pair, and then half-wrapped with an aluminum foil shielding layer, and then the metal wire is braided into a metal wire braided shielding reinforcement layer, and finally a plastic outer sheath is formed by injection molding through an injection molding machine head to obtain an Ethernet high-efficiency shielded low-loss high-frequency transmission cable.

[0036] Different from the prior art, the Ethernet high-efficiency shielded low-loss high-frequency transmission cable of the present invention prevents the contact oxidation of oxygen in the air with the surface of multiple strands of oxygen-free copper cores through the dielectric insulation layer, greatly reduces the dielectric constant of the transmission line and the loss of the copper oxide film on the surface of the copper conductor, and can meet the requirements of the automotive industry Ethernet for electromagnetic compatibility, high reliability, low electromagnetic radiation, low power consumption, bandwidth allocation, low latency and synchronous real-time performance, thereby reducing production costs.

[0037] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. An Ethernet high-efficiency shielded low-loss high-frequency transmission cable, characterized in that: The invention comprises a wire core, wherein the wire core comprises a plurality of oxygen-free copper cores, the outer side of the plurality of oxygen-free copper cores is coated with a dielectric insulation layer, the outer side of the dielectric insulation layer is coated with an aluminum foil shielding layer, a metal wire braided shielding reinforcement layer and a plastic outer sheath in sequence, and the dielectric insulation layer is a supercritical fluid micro-closed-cell foam material.

2. The Ethernet high-efficiency shielded low-loss high-frequency transmission cable according to claim 1, characterized in that: The aluminum foil shielding layer is a half-lapped aluminum foil winding layer with a thickness of 63-72 um.

3. The Ethernet high-efficiency shielded low-loss high-frequency transmission cable according to claim 1, characterized in that: The metal wire braided shielding reinforcement layer is a mesh braided layer formed by braiding aluminum-magnesium wires, red copper and tinned copper wires.

4. The Ethernet high-efficiency shielded low-loss high-frequency transmission cable according to claim 1, characterized in that: The dielectric insulating layer is a supercritical fluid micro-closed-cell foaming material formed by adding nitrogen or carbon dioxide into a polymer dielectric material. The polymer dielectric material is thermoplastic polyurethane rubber, block polyetheramide resin, ethylene-vinyl acetate copolymer or thermoplastic elastomer.

5. The Ethernet high-efficiency shielded low-loss high-frequency transmission cable according to claim 1, characterized in that: The plastic outer sheath is a polyvinyl chloride sheath, a polyethylene sheath, a thermoplastic polyurethane sheath, or a low-smoke halogen-free sheath.

6. The Ethernet high-efficiency shielded low-loss high-frequency transmission cable according to claim 1, characterized in that: The wire cores form a cross twisted pair.

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