Fire-resistant network cable for motor train unit

Abstract

The utility model relates to a cable, in particular to a fire-resistant cable for a motor train unit. The utility model aims to provide the fire-resistant network cable for the motor train unit, and the cable has the characteristics of high temperature resistance and adaptability to severe environments on the premise of having the transmission performance of a category 6 enhanced network. According to the technical scheme, the fire-resistant network cable for the motor train unit comprises a cable core, and a first belting layer, a shielding layer, a second belting layer and an outer protective layer which sequentially wrap the cable core from inside to outside, and is characterized in that the cable core comprises a filling wire and a plurality of conducting wires which are centrosymmetric and are spirally wound on the filling wire; each wire comprises a conductor, a first insulating layer and a second insulating layer, wherein the first insulating layer and the second insulating layer sequentially wrap the conductor.

Description

Technical Field

[0001] This utility model relates to a cable, specifically a fire-resistant cable for high-speed trains. Background Technology

[0002] With the rapid development of high-speed train technology, the rail transit sector has placed more stringent technical requirements on the comprehensive performance of special cables. In data transmission systems, fire-resistant network cables, as core connecting components of train control systems, safety monitoring systems, and communication equipment, directly impact operational safety and emergency response efficiency. Conventional network cables are prone to insulation failure, conductor oxidation, or structural loosening under high-temperature conditions, leading to signal transmission interruptions. Under long-term vibration, traditional cable stranding processes are prone to conductor breakage or insulation wear, affecting the stability of the entire cable system. Furthermore, the mineral oil and fuel oil encountered during vehicle operation, as well as environmental regulations restricting low-smoke, halogen-free, and low-toxicity materials, all impose stringent requirements on the material compatibility and environmental adaptability of cables. Therefore, considering the complex operating conditions of high-speed trains—including high-frequency vibration, alternating electromagnetic interference, oil-based corrosion, and potential fire risks—existing high-speed train cables still have room for optimization in terms of compact structural design, mechanical durability, and fire safety performance. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings in the above-mentioned background technology and provide a fire-resistant network cable for high-speed trains. This cable has the characteristics of high temperature resistance and adaptability to harsh environments while possessing Category 6 network transmission performance.

[0004] The technical solution of this utility model is:

[0005] A fire-resistant network cable for high-speed trains includes a cable core and a first wrapping layer, a shielding layer, a second wrapping layer, and an outer sheath that are sequentially wrapped around the cable core from the inside out. The cable core includes filler wires and a plurality of conductors with the filler wires spirally wound in a centrally symmetrical manner.

[0006] The wire includes a conductor and a first insulating layer and a second insulating layer that sequentially cover the conductor.

[0007] The conductor is a multi-strand, tightly packed tinned copper stranded wire.

[0008] The first insulating layer is a high-density polyethylene layer; the second insulating layer is a ceramicized silicone rubber layer.

[0009] The shielding layer includes an inner shielding layer and an outer shielding layer that are sequentially wrapped around the first wrapping layer from the inside out.

[0010] The inner shielding layer is a wrapping layer of aluminum foil polyester composite tape.

[0011] The outer shielding layer is a tin-plated copper wire braided layer.

[0012] Both the first and second wrapping layers are flame-retardant, low-smoke, halogen-free wrapping layers.

[0013] The filler wire is a polyester wire covered with a flame-retardant, low-smoke, halogen-free insulation layer.

[0014] The outer protective layer is a flame-retardant, low-smoke, halogen-free outer protective layer.

[0015] The beneficial effects of this utility model are:

[0016] 1. The cable core of this utility model adopts a multi-conductor spiral stranded filled wire cable core structure, which enhances the anti-interference ability, mechanical stability and structural reliability of the cable while possessing the transmission performance of Category 6 network, and improves the roundness of the cable core.

[0017] 2. The wrapping layer and outer sheath of this utility model are both made of flame-retardant, low-smoke, halogen-free materials, which gives the cable excellent flame-retardant and high-temperature resistance properties. At the same time, it has the advantages of low smoke, halogen-free, low toxicity and high light transmittance, ensuring the normal operation of the cable under harsh working conditions.

[0018] 3. The filler wire in the center of the cable core of this utility model is polyester wire and covered with a low-density flame-retardant low-smoke halogen-free insulation layer. The conductor inside the cable core is made by a process of twisting fine wires into multiple strands. While ensuring the structural strength and fire resistance of the cable core, the overall weight of the cable is greatly reduced.

[0019] 4. The shielding layer of this utility model adopts a composite structure, which improves the transmission performance, electromagnetic interference resistance and shielding efficiency of the cable. Attached Figure Description

[0020] Figure 1 This is a cross-sectional structural diagram of an embodiment of the present invention.

[0021] Figure label:

[0022] Conductor 1, First insulating layer 2, Second insulating layer 3, First wrapping layer 4, Inner shielding layer 5, Outer shielding layer 6, Second wrapping layer 7, Outer sheath 8, Filler wire 9. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.

[0024] like Figure 1As shown, a fire-resistant network cable for high-speed trains includes a cable core, a first wrapping layer 4, a shielding layer, a second wrapping layer 7, and an outer sheath 8. The cable core is covered by the first wrapping layer, the shielding layer, the second wrapping layer, and the outer sheath in sequence from the inside out.

[0025] like Figure 1 As shown, the cable core includes a filler wire 9 and several conductors.

[0026] As shown in the figure, the four conductors are symmetrically arranged and spirally twisted around the filler wire. At any cross-section of the cable core, the four conductors and the cable core form a "cross" shape. Compared to cable cores composed of twisted pairs or multiple twisted pairs, the cable core of this invention has stronger anti-interference capabilities, higher mechanical strength, and reliable structural stability. Furthermore, the denser filling of the cable core effectively disperses the pressure on the outer sheath of the cable, making it more suitable for the vibration environment of high-speed trains. Simultaneously, cables using this structure can effectively reduce signal reflection and weaken the skin effect generated during high-frequency signal transmission.

[0027] The filler wire is a polyester wire with an outer flame-retardant, low-smoke, halogen-free insulation layer, which serves a supporting function. The flame-retardant, low-smoke, halogen-free insulation layer has a low material density (1.4 g / cm³). 3 ~1.5g / cm 3 It is significantly lower than the 2.1–2.2 g / cm³ of other materials, such as the commonly used polytetrafluoroethylene (PTFE). 3 This significantly reduces the weight while improving the overall flame retardancy of the cable.

[0028] The wire includes a conductor 1, a first insulating layer 2, and a second insulating layer 3.

[0029] The conductor is manufactured using a fine-wire multi-strand stranding process (several tinned copper wires are stranded together and compressed into a single strand to form a compacted tinned copper stranded wire). The conductor is 20 AWG (single wire outer diameter 0.20 mm), with a plating thickness ≥ 0.7 μm, a single-strand tensile strength > 196 MPa, and an elongation > 15%, conforming to GB / T 4910 standards. Through the fine-wire multi-strand stranding process, the outer diameter of the conductor is reduced by at least 0.04 mm to 0.08 mm compared to conventional conductors, which reduces the weight of the finished cable and improves the conductor's roundness, thereby enhancing the cable's signal transmission performance.

[0030] The first and second insulation layers employ a double-layer tandem extrusion technology (simultaneously extruding two different materials within the same mold to form a tightly bonded double-layer composite structure, avoiding the secondary processing defects of traditional step extrusion). The first insulation layer adheres tightly to the conductor to enhance adhesion. It is made of solid high-density polyethylene and has a low dielectric constant. The second insulation layer covers the first insulation layer and is made of a ceramicized material (ceramized silicone rubber) based on polyethylene, enhancing the overall fire resistance of the cable and ensuring efficient signal transmission even under high-temperature conditions such as fires. The overall thickness of the first and second insulation layers is preferably 0.80mm to 0.85mm, with the first insulation layer preferably 0.40mm and the second insulation layer preferably 0.45mm. The first and second insulation layers on the four conductors are distinguished by different colors.

[0031] The first wrapping layer covers the cable core. The thickness of the wrapping layer is greater than 0.2 mm, and it is processed by wrapping. The second wrapping layer covers the shielding layer. Both the first and second wrapping layers are flame-retardant, low-smoke, halogen-free tapes. This material has a high flame-retardant rating, which can effectively improve the flame-retardant rating of the cable.

[0032] The shielding layer includes an inner shielding layer 5 and an outer shielding layer 6. The inner shielding layer and the outer shielding layer are sequentially wrapped around the outside of the first wrapping layer from the inside out.

[0033] The inner shielding layer is a wrapping layer composed of aluminum foil and polyester composite tape, and is manufactured using a longitudinal wrapping process. The thickness of the inner shielding layer is 0.090mm to 0.098mm, of which the aluminum foil thickness is 0.55mm to 0.60mm, and the overlap rate is controlled at 25% to 30%. This inner shielding layer has a thicker aluminum foil, making it easier to process and shape, and can effectively improve the attenuation and near-end crosstalk performance of the cable in the low-frequency band.

[0034] The outer shielding layer is a tinned copper wire braided layer, with a single wire diameter of 0.08mm to 0.10mm and a braiding density greater than 90%. The inner and outer shielding layers sequentially cover the cable core, and the inner and outer shielding layers are formed in one process, further improving the cable's shielding efficiency and giving the cable excellent anti-electromagnetic interference capabilities, meeting the cable's usage requirements in environments with strong interference.

[0035] The outer protective layer is made of flame-retardant, low-smoke, halogen-free material. The outer protective layer possesses advantages such as excellent flame retardancy, high light transmittance, low hardness (Shore A 88), low-temperature resistance, halogen-free nature, low toxicity, good mechanical properties, and good processability.

[0036] This invention features a compact structure (the cross-sections of the four conductors are radially distributed in a "cross-shaped" pattern, and they are twisted together to form a spiral symmetrical structure) and has advantages such as fire resistance, high shielding, stable transmission rate, resistance to mineral oil and fuel oil, high light transmittance, low hardness, halogen-free, low toxicity, and excellent mechanical properties. It can withstand high and low temperatures ranging from -50℃ to 90℃ and can meet the requirements for long-term use at 80℃.

[0037] The fire-resistant network cable for high-speed trains provided by this utility model has high-efficiency signal transmission capability and strong anti-interference capability; it can be applied to scenarios such as high-speed train equipment interconnection, real-time control, fault diagnosis and detection, emergency communication, and video surveillance.

[0038] All materials described in this invention can be purchased externally.

[0039] The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

Claims

1. A fire-resistant network cable for high-speed trains, comprising a cable core and, from the inside out, a first wrapping layer (4), a shielding layer, a second wrapping layer (7), and an outer sheath (8), characterized in that: The cable core includes a filler wire (9) and a plurality of conductors that are centrally symmetrical and spirally wound with the filler wire; The wire includes a conductor (1) and a first insulating layer (2) and a second insulating layer (3) sequentially covering the conductor; The conductor is a multi-strand, tightly packed tinned copper stranded wire; The first insulating layer is a high-density polyethylene layer; the second insulating layer is a ceramicized silicone rubber layer.

2. The fire-resistant network cable for high-speed trains according to claim 1, characterized in that: The shielding layer includes an inner shielding layer (5) and an outer shielding layer (6) that are sequentially wrapped around the first wrapping layer from the inside out.

3. The fire-resistant network cable for high-speed trains according to claim 2, characterized in that: The inner shielding layer is a wrapping layer of aluminum foil polyester composite tape.

4. A fire-resistant network cable for high-speed trains according to claim 3, characterized in that: The outer shielding layer is a tin-plated copper wire braided layer.

5. A fire-resistant network cable for high-speed trains according to claim 4, characterized in that: Both the first and second wrapping layers are flame-retardant, low-smoke, halogen-free wrapping layers.

6. A fire-resistant network cable for high-speed trains according to claim 5, characterized in that: The filler wire is a polyester wire covered with a flame-retardant, low-smoke, halogen-free insulation layer.

7. A fire-resistant network cable for high-speed trains according to claim 6, characterized in that: The outer protective layer is a flame-retardant, low-smoke, halogen-free outer protective layer.

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