Signal cable for low-smoke halogen-free thin-wall railway passenger car

Abstract

The invention relates to the field of passenger car signal cables, in particular to a low-smoke halogen-free thin-wall signal cable for a railway passenger car, which comprises a battery cell, a protective skin layer, an insulating sleeve, an inner electromagnetic shielding structure, an outer electromagnetic shielding structure and other functional layers, the inner electromagnetic shielding structure is composed of a nanocrystalline alloy layer, a graphene composite layer, a metalized ceramic fiber layer and an outermost electromagnetic absorption layer from inside to outside, and can absorb electromagnetic waves of different frequency bands in an omnibearing mode. The outer electromagnetic shielding structure mainly adopts spiral wrapping copper foil and is matched with sealant to strengthen shielding effectiveness, in the aspect of electromagnetic shielding, the inner structure and the outer structure are cooperated, full-band efficient protection is achieved, the shielding material far exceeds a traditional single-band shielding material, complex electromagnetic interference is powerfully resisted, accurate and stable signal transmission is ensured, and heat insulation and flame retardance are achieved. The multiple ceramic fiber layers are matched with the hydrated salt layer and the low-smoke halogen-free flame-retardant layer to construct an efficient heat-insulating flame-retardant system, so that fire spreading is greatly slowed down during a fire, heat conduction and flame diffusion are inhibited, and personnel evacuation and fire extinguishing rescue are guaranteed.

Description

Technical Field

[0001] The invention relates to the field of passenger car signal cables, and in particular to a low-smoke, halogen-free, thin-walled signal cable for railway passenger cars. Background Art

[0002] With the rapid development of railway passenger car technology, its electrical system is becoming increasingly complex, and the requirements for signal cable performance are becoming more and more stringent. Traditional signal cables have gradually exposed many deficiencies in electromagnetic shielding, thermal insulation and flame retardancy, as well as mechanical and chemical protection. In the field of electromagnetic shielding, the existing cable structure mostly uses a single or simple composite shielding material, which can only play a limited role in suppressing electromagnetic interference in a specific frequency band. In the complex electromagnetic environment of railway passenger cars, such as the interweaving interference of on-board communication equipment, electrical control systems and external electromagnetic radiation sources, the stability of signal transmission is severely damaged, the bit error rate rises, and signal distortion occurs frequently, resulting in a significant increase in the risk of misjudgment of train operation instructions and equipment malfunction, threatening driving safety and reliable system operation; in the face of fire hazards, conventional cables have poor thermal insulation and flame retardancy, lack of efficient thermal insulation layer and flame retardant mechanism coordination, and it is difficult to effectively prevent heat from being transmitted to the battery cells and key components during a fire, and it is impossible to suppress the spread of flames along the cable. Thick smoke and toxic gases are released wantonly, endangering the lives and health of passengers; high temperatures can easily cause cable insulation aging, short circuits, and even explosions, paralyzing the electrical system and causing the train's braking, lighting, and communication systems to fail, exacerbating the consequences of the disaster and making it difficult to meet the high standards for fire safety in railway passenger cars.

[0003] Therefore, it is necessary to propose a low-smoke, halogen-free, thin-walled railway passenger car signal cable to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a low-smoke, halogen-free, thin-walled signal cable for railway passenger cars, so as to solve the problems that the existing cable structure mostly adopts a single or simple composite shielding material, which can only play a limited inhibitory effect on electromagnetic interference in a specific frequency band, and the conventional cable has poor thermal insulation and flame retardant performance and lacks the synergy between the efficient thermal insulation layer and the flame retardant mechanism.

[0005] To achieve the above object, the present invention provides the following technical solutions: A low-smoke, halogen-free, thin-walled railway passenger car signal cable comprises a plurality of battery cells, wherein a protective cortex is arranged on the outer side of the battery cell, an insulating sleeve is arranged on the outer side of the protective cortex, an inner electromagnetic shielding structure is arranged on the outer side of the insulating sleeve, an outer electromagnetic shielding structure is arranged on the outer side of the inner electromagnetic shielding structure, the outer electromagnetic shielding structure is used to reflect external electromagnetic waves, the inner electromagnetic shielding structure is used to absorb part of the external electromagnetic waves that pass through the outer electromagnetic shielding structure, the inner electromagnetic shielding structure comprises nanocrystalline alloy layers from the inside to the outside, a graphene composite layer is arranged on the outer side of the nanocrystalline alloy layer, A metallized ceramic fiber layer is arranged on the outside of the graphene composite layer, an outermost electromagnetic absorption layer is arranged on the outside of the metallized ceramic fiber layer, the outer electromagnetic shielding structure comprises a copper foil, a sealant is arranged on the outside of the copper foil, the sealant is used to fill the gaps and holes of the copper foil, an insulating anti-oxidation layer is arranged on the outside of the sealant, a flame retardant layer is arranged on the outside of the insulating anti-oxidation layer, a ceramic fiber layer is arranged on the outside of the flame retardant layer, a cavity is arranged inside the ceramic fiber layer, a hydrated salt layer is arranged in the cavity, and an insulating outer skin layer is arranged on the outside of the ceramic fiber layer.

[0006] Preferably, the copper foil is spirally and uniformly wrapped around the outer side of the outermost electromagnetic absorption layer.

[0007] Preferably, the number of the ceramic fiber layers is six, and the ceramic fiber layers are uniformly wrapped around the outer side of the flame retardant layer.

[0008] Preferably, the protective skin layer is made of polyethylene terephthalate, the insulating sleeve is made of polyimide, and the insulating outer skin layer is made of cross-linked polyethylene polymer material.

[0009] Preferably, the nanocrystalline alloy layer is made of an iron-based nanocrystalline alloy, the graphene composite layer is made of graphene and polyaniline polymer material, the metallized ceramic fiber layer is made of nickel-plated ceramic fiber, and the outermost electromagnetic absorption layer is made of ferrite powder polymer.

[0010] Preferably, the sealant is made of epoxy resin, wherein the sealant is doped with iron powder.

[0011] Preferably, the insulating anti-oxidation layer is made of polyimide film.

[0012] Preferably, the flame retardant layer is made of low-smoke halogen-free flame retardant material.

[0013] Preferably, the ceramic fiber layer is made of alumina.

[0014] Preferably, the material of the hydrated salt layer is sodium sulfate decahydrate.

[0015] Technical effects and advantages of the present invention: 1. In the internal electromagnetic shielding structure, the nanocrystalline alloy layer efficiently absorbs low-frequency magnetic field interference, accurately captures low-frequency electromagnetics, and makes up for the traditional shortcomings; the graphene composite layer has strong reflection and attenuation to resist interference; the metallized ceramic fiber layer is resistant to high temperatures and mechanically strong, and it efficiently shields the high-frequency band while supporting the whole; the outermost electromagnetic absorption layer absorbs residual high-frequency electromagnetics and deeply attenuates residual energy. The copper foil of the external electromagnetic shielding structure reflects a large amount of electromagnetic interference by virtue of its high conductivity, and the sealant fills the gaps and the iron powder is optimized to construct a continuous, uniform and highly sealed shielding layer. Internal and external synergy, all-round interception from low frequency to high frequency, ultra-traditional focus on single frequency band shielding.

[0016] 2. Multiple ceramic fiber layers tightly surround the flame retardant layer to build an efficient thermal insulation system. The low-smoke halogen-free flame retardant layer burns to produce a dense carbonized layer that blocks oxygen and combustible gases, slowing down the spread of fire and inhibiting the spread of flames along the cable, creating favorable conditions for personnel evacuation, fire fighting and rescue.

[0017] 3. The insulating anti-oxidation layer is a copper foil covering to block the erosion of air, water vapor, and chemical pollutants, and prevent the copper foil from oxidizing and corroding, causing the conductivity to decrease and the shielding to fail. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a schematic structural diagram of a low-smoke, halogen-free, thin-walled railway passenger car signal cable.

[0019] Figure 2 It is a schematic diagram of the front view structure of the cable of the present invention.

[0020] Figure 3 For the present invention Figure 2 Schematic diagram of the enlarged structure at point A proposed in.

[0021] Figure 4 This is a schematic diagram of the structure of the copper foil spirally and evenly wrapped around the outermost electromagnetic absorption layer of the present invention.

[0022] In the figure: 1. battery cell; 2. protective skin layer; 3. insulating sleeve; 4. inner electromagnetic shielding structure; 41. nanocrystalline alloy layer; 42. graphene composite layer; 43. metallized ceramic fiber layer; 44. outermost electromagnetic absorption layer; 5. outer electromagnetic shielding structure; 51. copper foil; 52. sealant; 6. insulating anti-oxidation layer; 7. flame retardant layer; 8. ceramic fiber layer; 9. cavity; 10. hydrated salt layer; 11. insulating outer skin layer. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The present invention provides Figure 1-Figure 4 A low-smoke, halogen-free, thin-walled railway passenger car signal cable is shown, comprising a plurality of battery cells 1, a protective skin layer 2 is arranged on the outside of the battery cell 1, an insulating sleeve 3 is arranged on the outside of the protective skin layer 2, an inner electromagnetic shielding structure 4 is arranged on the outside of the insulating sleeve 3, an outer electromagnetic shielding structure 5 is arranged on the outside of the inner electromagnetic shielding structure 4, the outer electromagnetic shielding structure 5 is used to reflect external electromagnetic waves, and the inner electromagnetic shielding structure 4 is used to absorb part of the external electromagnetic waves that pass through the outer electromagnetic shielding structure 5, the inner electromagnetic shielding structure 4 comprises a nanocrystalline alloy layer 41 from the inside to the outside, a graphene composite layer 42 is arranged on the outside of the nanocrystalline alloy layer 41, and a graphene A metallized ceramic fiber layer 43 is arranged on the outside of the composite layer 42, an outermost electromagnetic absorption layer 44 is arranged on the outside of the metallized ceramic fiber layer 43, an outer electromagnetic shielding structure 5 includes a copper foil 51, a sealant 52 is arranged on the outside of the copper foil 51, the sealant 52 is used to fill the gaps and holes of the copper foil 51, an insulating anti-oxidation layer 6 is arranged on the outside of the sealant 52, a flame retardant layer 7 is arranged on the outside of the insulating anti-oxidation layer 6, a ceramic fiber layer 8 is arranged on the outside of the flame retardant layer 7, a cavity 9 is arranged inside the ceramic fiber layer 8, and a hydrated salt layer 10 is arranged in the cavity 9, and an insulating outer skin layer 11 is arranged on the outside of the ceramic fiber layer 8; Furthermore, the material of the protective skin layer 2 is polyethylene terephthalate, the material of the insulating sleeve 3 is polyimide, and the material of the insulating outer skin layer 11 is a cross-linked polyethylene polymer material; Furthermore, the copper foil 51 is spirally and uniformly wrapped around the outer side of the outermost electromagnetic absorption layer 44; Furthermore, the sealant 52 is made of epoxy resin, wherein the sealant 52 is doped with iron powder; The insulating anti-oxidation layer 6 is made of polyimide film; In the embodiment of the present invention, the copper foil 51 is spirally and evenly wrapped on the outside of the outermost electromagnetic absorption layer 44 to construct a continuous and uniform electromagnetic shielding layer. Its high conductivity allows external electromagnetic waves to generate a reverse magnetic field to offset the incident electromagnetic waves when they encounter the copper foil, reflecting a large amount of electromagnetic interference to prevent it from entering the cable and affecting the signal transmission components. The spiral wrapping is tight and seamless to avoid electromagnetic "leakage". The sealant 52 further fills the gaps and holes to prevent external electromagnetic interference from invading from tiny defects. The iron powder can construct an electromagnetic shielding layer, reflect and attenuate electromagnetic waves, enhance shielding effectiveness, enhance the integrity and sealing of the shielding structure, and improve the shielding effect as well as operational safety and reliability. The insulating anti-oxidation layer made of polyimide film material can prevent air from oxidizing the copper foil 51.

[0025] See also Figure 3 In one embodiment of the present invention, the number of the ceramic fiber layers 8 is six, and the ceramic fiber layers 8 are uniformly wrapped around the outer side of the flame retardant layer 7; Furthermore, the flame retardant layer 7 is made of low-smoke halogen-free flame retardant material, and the ceramic fiber layer 8 is made of alumina; Furthermore, the material of the hydrated salt layer 10 is sodium sulfate decahydrate; In the embodiment of the present invention, ceramic fiber is a fibrous lightweight refractory material with light weight and high temperature resistance. When a fire occurs outside, the ceramic fiber layer 8 can withstand the high temperature outside, and the internal cavity 9 can ensure that the internal temperature of the ceramic fiber layer 8 remains at the current state. After a period of time, as the temperature inside the ceramic fiber layer 8 gradually increases, because the sodium sulfate decahydrate will gradually turn into a liquid after absorbing a large amount of heat, the solid hydrated salt layer 10 will absorb a large amount of heat to ensure that the internal battery core is not damaged. Multiple ceramic fiber layers 8 are evenly wrapped on the outside of the flame retardant layer 7, which significantly enhances the thermal insulation capacity of the cable. After the ceramic fiber layer 8 fails, the flame retardant layer 7 further isolates the heat transfer. The low-smoke halogen-free flame retardant material produces less smoke and low toxicity when burned. A dense carbonized layer is formed during combustion to block the contact between oxygen and combustible gas and slow down the combustion process.

[0026] See also Figure 1 In one embodiment of the present invention, the nanocrystalline alloy layer 41 is made of an iron-based nanocrystalline alloy, the graphene composite layer 42 is made of graphene and polyaniline polymer materials, the metallized ceramic fiber layer 43 is made of nickel-plated ceramic fiber, and the outermost electromagnetic absorption layer 44 is made of ferrite powder polymer; In the embodiment of the present invention, the nanocrystalline alloy layer 41 can efficiently absorb low-frequency magnetic field interference, the graphene composite layer 42 has a strong reflection and attenuation effect on medium and low frequency electromagnetic interference, the metallized ceramic fiber layer 43 has high mechanical strength and high temperature resistance, shields high-frequency electromagnetic waves and provides support and protection for the internal layer, and the outermost electromagnetic absorption layer 44 further attenuates the residual high-frequency electromagnetic by absorbing the loss mechanism. The design of the inner electromagnetic shielding structure 4 and the outer electromagnetic shielding structure 5 further enhances the electromagnetic shielding effectiveness, which far exceeds the single frequency band shielding of conventional materials.

[0027] Working principle of the present invention: With high conductivity, the copper foil 51 of the external electromagnetic shielding structure rapidly generates eddy current on its surface under the action of external electromagnetic waves according to the law of electromagnetic induction. The eddy current forms a reverse magnetic field, which cancels out the incident electromagnetic waves, thus achieving reflection blocking of a large amount of external electromagnetic interference and preventing it from entering the cable to interfere with signal transmission components. The spiral uniform wrapping method ensures that the copper foil 51 fits tightly and seamlessly, effectively avoiding electromagnetic leakage. The four layers of the inner electromagnetic shielding structure work together to achieve full-band electromagnetic interference processing. The layers work closely together to form a continuous shielding and absorption system from low frequency to high frequency, which can accurately capture and strongly suppress the residual electromagnetic interference that penetrates the outer electromagnetic shielding structure, and protect the internal signal transmission of the cable from electromagnetic pollution. When the fire causes the ambient temperature to rise and reach the phase transition temperature of sodium sulfate decahydrate (about 32°C), the hydrated salt undergoes a solid-liquid phase transition. This process absorbs a large amount of heat and the temperature remains constant. The flame retardant material decomposes under heat to produce non-combustible gases, such as carbon dioxide and nitrogen, which dilute the surrounding oxygen concentration and slow down the combustion reaction rate. At the same time, a dense carbonized layer is generated to cover the cable surface. The carbonized layer has low thermal conductivity and strong barrier properties, which cuts off the contact channel between oxygen and combustible gas, prevents the flame from spreading along the cable longitudinally, curbs the expansion of the fire, and reduces the release of smoke and toxic gases.

[0028] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A low-smoke, halogen-free, thin-walled railway passenger car signal cable, comprising a plurality of battery cells (1), characterized in that: The battery core (1) is provided with a protective skin layer (2) on the outside, an insulating sleeve (3) is provided on the outside of the protective skin layer (2), an inner electromagnetic shielding structure (4) is provided on the outside of the insulating sleeve (3), an outer electromagnetic shielding structure (5) is provided on the outside of the inner electromagnetic shielding structure (4), the outer electromagnetic shielding structure (5) is used to reflect external electromagnetic waves, the inner electromagnetic shielding structure (4) is used to absorb part of the external electromagnetic waves that pass through the outer electromagnetic shielding structure (5), the inner electromagnetic shielding structure (4) comprises, from inside to outside, a nanocrystalline alloy layer (41), a graphene composite layer (42) is provided on the outside of the nanocrystalline alloy layer (41), a metallized ceramic fiber layer (42) is provided on the outside of the graphene composite layer (42), and a metallized ceramic fiber layer (41) is provided on the outside of the graphene composite layer (42). 3), an outermost electromagnetic absorption layer (44) is arranged on the outer side of the metallized ceramic fiber layer (43), the outer electromagnetic shielding structure (5) comprises a copper foil (51), a sealant (52) is arranged on the outer side of the copper foil (51), the sealant (52) is used to fill the gaps and holes of the copper foil (51), an insulating anti-oxidation layer (6) is arranged on the outer side of the sealant (52), a flame retardant layer (7) is arranged on the outer side of the insulating anti-oxidation layer (6), a ceramic fiber layer (8) is arranged on the outer side of the flame retardant layer (7), a cavity (9) is arranged inside the ceramic fiber layer (8), and a hydrated salt layer (10) is arranged in the cavity (9), and an insulating outer skin layer (11) is arranged on the outer side of the ceramic fiber layer (8).

2. The low-smoke, halogen-free, thin-walled railway passenger car signal cable according to claim 1, characterized in that: The copper foil (51) is spirally and evenly wrapped around the outside of the outermost electromagnetic absorption layer (44).

3. The low-smoke, halogen-free, thin-walled railway passenger car signal cable according to claim 1, characterized in that: The number of the ceramic fiber layers (8) is six, and the ceramic fiber layers (8) are evenly wrapped around the outside of the flame retardant layer (7).

4. The low-smoke, halogen-free, thin-walled railway passenger car signal cable according to claim 1, characterized in that: The material of the protective skin layer (2) is polyethylene terephthalate, the material of the insulating sleeve (3) is polyimide, and the material of the insulating outer skin layer (11) is a cross-linked polyethylene polymer material.

5. The low-smoke, halogen-free, thin-walled railway passenger car signal cable according to claim 1, characterized in that: The material of the nanocrystalline alloy layer (41) is an iron-based nanocrystalline alloy, the material of the graphene composite layer (42) is a graphene and polyaniline polymer material, the material of the metallized ceramic fiber layer (43) is a nickel-plated ceramic fiber, and the material of the outermost electromagnetic absorption layer (44) is an iron oxide powder polymer.

6. The low-smoke, halogen-free, thin-walled railway passenger car signal cable according to claim 1, characterized in that: The sealant (52) is made of epoxy resin, wherein the sealant (52) is doped with iron powder.

7. The low-smoke, halogen-free, thin-walled railway passenger car signal cable according to claim 1, characterized in that: The insulating anti-oxidation layer (6) is made of a polyimide film.

8. The low-smoke, halogen-free, thin-walled railway passenger car signal cable according to claim 1, characterized in that: The flame retardant layer (7) is made of low-smoke halogen-free flame retardant material.

9. The low-smoke, halogen-free, thin-walled railway passenger car signal cable according to claim 1, characterized in that: The ceramic fiber layer (8) is made of aluminum oxide.

10. The low-smoke, halogen-free, thin-walled railway passenger car signal cable according to claim 1, characterized in that: The material of the hydrated salt layer (10) is sodium sulfate decahydrate.

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