Weather-proof easy-to-recognize novel rail transit railway digital signal cable and preparation method thereof

Abstract

The invention provides a weather-proof easily-recognized novel rail traffic railway digital signal cable and a preparation method thereof, and aims to solve the problems that an existing railway signal cable is insufficient in environmental adaptability, identification is prone to losing efficacy, and the appearance is difficult to distinguish, the cable comprises a cable core and a protective layer, and the cable core comprises a four-wire set and a copper strip shielding layer; each insulating single wire is composed of an oxygen-free copper conductor and an insulating layer. The protective layer comprises a multi-layer structure including a wrapping tape layer, a heat insulation protective layer, an aluminum protective layer and the like, and the outer side of the outer sheath layer is provided with a marking strip; materials such as insulating materials of each layer and the outer sheath are innovated, the identification degree of the cable ground marking strip is high, the durability is high, a fault cable can be rapidly positioned, misoperation is prevented, and the signal transmission requirements of different scenes of rail transit are met. The method can be widely applied to places with high performance and safety requirements, such as high-speed railways, subways, urban rail transit and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of railway signal cables, and in particular to a weather-resistant and easy-to-identify novel rail transit railway digital signal cable and a preparation method thereof. Background Art

[0002] With the rapid development of rail transit and railway construction, cables are increasingly used in rail transit systems such as subways and high-speed railways. Signal cables, as key components to ensure signal transmission and safe operation of the system, need to work stably for a long time in various complex environments.

[0003] The invention with application publication number CN110853799A discloses a "railway digital signal cable", whose cable core includes at least one star-shaped four-wire group; a monitoring capacitor plate assembly is arranged between the inner tape layer and the outer tape layer of the star-shaped four-wire group, and the monitoring capacitor plate on each side is composed of a number of capacitor plate units, and the lengths of the capacitor plate units are not equal; the wire group shielding structure includes a wire group shielding corrugated belt and a wire group shielding support ring supported in the wire group shielding corrugated belt at intervals; the armor layer includes a wrapped inner layer wrapped steel belt and an outer layer wrapped steel belt, and a rubber sealing belt is embedded between the overlapping sections of the inner layer wrapped steel belt and the outer layer wrapped steel belt. The signal cable can effectively monitor the timely operation status of the cable and has good pressure resistance and water resistance. However, the invention lacks a protective layer and is prone to aging, damage and other problems when exposed to harsh environments such as high temperature, humidity, and corrosion for a long time, affecting signal transmission and making it difficult to adapt to complex environments.

[0004] In order to better adapt to the environment, the invention with application publication number CN109087745A discloses a "high-temperature resistant cable for railways", including a metal armored sheath, a high-temperature resistant insulating filling layer, a thermally conductive ring and a thermally conductive rod assembly. The inner side of the metal armored sheath is covered with a braided reinforcement layer, and the inner side of the braided reinforcement layer is covered with a shielding layer. A high-temperature resistant insulating filling layer is arranged inside the shielding layer, and a thermally conductive ring is arranged in the middle of the high-temperature resistant insulating filling layer. An axial conductor is arranged inside the thermally conductive ring, and multiple secondary conductors are arranged on the outside of the thermally conductive ring inside the high-temperature insulating filling layer. The cable of this invention quickly transfers the heat in the high-temperature resistant cable for railways to the metal armored sheath through the cooperation of the thermally conductive ring and the thermally conductive rod assembly, and the convex ring arranged on the thermally conductive rod assembly increases its contact area with the inside of the cable, further enhancing the heat dissipation performance of the thermally conductive rod assembly. However, this invention lacks cable identification, making it difficult to distinguish cable performance, affecting maintenance efficiency, and may even lead to misjudgment and misoperation.

[0005] In summary, existing railway signal cables generally have the following disadvantages: 1) Insufficient environmental adaptability: Existing railway signal cables lack key protective layers such as thermal insulation and oxygen barrier layers. Long-term exposure to harsh environments such as high temperature, humidity, and corrosion can easily lead to aging and damage, affecting signal transmission. They are difficult to adapt to complex environments and have poor environmental adaptability in actual applications, limiting their service life. 2) Markings are prone to failure: Existing railway signal cable markings, such as ink, are easily affected by solvents, friction, and ultraviolet rays, fading or falling off. Their lifespan is particularly short in outdoor or high-humidity environments. Traditional raised marking processes are often affected by external environmental factors such as moisture, dust, and friction, resulting in blurred markings, which makes cable maintenance, inspection, and management difficult. 3) Difficult to distinguish by appearance: Existing cables with different functions and specifications may look similar. When one of the cables fails and needs repair, it is difficult to quickly and accurately identify the cable to be repaired by relying solely on traditional fuzzy markings, which affects the maintenance efficiency and may even lead to misjudgment and misoperation. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems in the prior art and to propose a new type of weather-resistant and easy-to-identify rail transit railway digital signal cable and its preparation method, which can solve the problems of insufficient environmental adaptability, easy failure of identification and difficult to distinguish appearance.

[0007] To achieve the above-mentioned objectives, the present invention proposes a new type of weather-resistant and easy-to-identify rail transit railway digital signal cable, comprising a cable core and a protective layer wrapped around the cable core, characterized in that: the cable core includes at least one set of four-wire groups, the four-wire group is twisted by four insulated single wires, and the insulated single wires include an oxygen-free copper conductor and an insulation layer from the inside to the outside; the protective layer is wrapped around the outside of the cable core, and the protective layer includes a tape layer, a thermal insulation protective layer, an aluminum sheath, an inner lining layer, an armor layer, an oxygen isolation layer and an outer sheath layer from the inside to the outside, and the identification strip is located on the outside of the outer sheath layer.

[0008] Preferably, the cable core also includes a copper tape shielding layer, which longitudinally covers the quad group 5, the quad group is star-shaped and symmetrical, and the thickness of the quad group is controlled at 90 to 290 mm; the oxygen-free copper conductor can reduce the loss during signal transmission to ensure good conductivity and signal transmission performance, and the conductor has a low elongation at break, ensuring stable and accurate transmission of railway signals; the insulated single wire has better flame retardant and fire resistance, lower transmission medium, good insulation performance, and high compressive performance.

[0009] Preferably, the insulating layer comprises an inner skin layer, an intermediate foaming layer and an outer skin layer from the inside out, the thickness of the inner skin layer is controlled to be 0.012 to 0.015 mm, and the thickness of the outer skin layer is controlled to be 0.15 to 0.20 mm.

[0010] Preferably, the wrapping layer includes a polyester tape and a low-smoke halogen-free flame-retardant tape, and the low-smoke halogen-free flame-retardant tape is located outside the low-smoke halogen-free flame-retardant tape to ensure the stability of the cable core structure.

[0011] Preferably, the thermal insulation protective layer is coated on the outside of the tape layer, and the thickness is controlled at 0.72-0.88 mm. The thermal insulation protective layer has uniform thickness, smooth surface and is tightly bonded to the cable core.

[0012] Preferably, the aluminum sheath is longitudinally coated on the outside of the thermal insulation protective layer, and the thickness of the aluminum sheath 9 is ≥1.2 mm, which effectively improves the cable core's ability to resist internal and external electromagnetic interference and ensures the stability of rail transit railway signal transmission.

[0013] Preferably, the inner lining layer is extruded on the outer surface of the aluminum sheath, and the thickness of the inner lining layer is controlled to be 1.0 to 1.2 mm, with uniform thickness and smooth and round surface.

[0014] Preferably, the thickness of the outer sheath layer is controlled at 1.8-2.2 mm, the width of the identification strip is controlled at 6-10 mm, and the thickness of the identification strip is controlled at 0.10-0.3 mm. The outer sheath layer can prevent oxygen from penetrating into the interior, protect the cable core wire, and avoid damage due to burning.

[0015] To achieve the above object, the present invention also proposes a method for preparing a new type of weather-resistant and easy-to-identify rail transit railway digital signal cable, comprising the following steps: a) Preparation of Insulated Single Wire: A single solid oxygen-free copper conductor that has undergone annealing is then coated with an insulating layer to form an insulated single wire. The inner layer of the insulating layer is made of fire-resistant solid polypropylene insulation material, the middle foam layer is made of polypropylene foam insulation material, and the outer layer is made of flame-retardant polyethylene insulation material. b) Cable core preparation: Several insulated single wires are twisted symmetrically in a star shape to form a quad. The outer side of the quad is selectively covered with a corrugated copper tape shield. The prepared quad and copper tape shield are twisted into a cable core according to color sequence and regular twist pitch. c) Preparation of the tape layer: Wrap the cable core with a layer of polyester tape and a layer of low-smoke halogen-free flame retardant tape; d) Preparation of thermal insulation protective layer: Use low-density polyethylene sheath material to extrude and coat the outer side of the tape layer; e) Aluminum sheath preparation: Aluminum strips are longitudinally covered and welded to form a highly flame-retardant polyolefin sheath material, which is then extruded on the outer surface of the aluminum sheath using an extruder with a high compression ratio to form an inner lining aluminum sheath; f) Preparation of inner lining layer: Use highly flame-retardant polyolefin sheath material and extrude it onto the outer surface of the aluminum sheath through an extruder with a high compression ratio to form an inner lining layer; g) Armour layer preparation: Galvanised steel strips are used for double-layer gap wrapping, with the steel strips tightly fitted together to form the armour layer; h) Preparation of oxygen barrier layer: Wrap flame retardant glass fiber oxygen barrier layer outside the armor layer to form an oxygen barrier layer; i) Preparation of outer sheath layer and identification strip: The outer sheath layer adopts a new type of weather-resistant and flame-retardant sheath material, and the identification strip is extruded together with the outer sheath layer.

[0016] Preferably, the insulating layer adopts a skin-foam-skin three-layer physical foaming technology.

[0017] Beneficial effects of the present invention: 1) Highly recognizable identification strip: The identification strip on the outer sheath has a distinct physical protrusion that contrasts sharply with the surrounding cable outer sheath both visually and by touch. This allows workers to quickly identify a specific cable even in dim light or with obstructed vision. 2) Strong durability: The identification strip is tightly integrated with the cable outer sheath, and has good wear resistance, corrosion resistance and weather resistance. It can maintain a stable shape and clear identification during long-term use and is not easily damaged or invalidated by external environmental factors. 3) Quickly locate faulty cables: When a cable fault occurs, the cable with identification strips allows maintenance personnel to quickly locate the faulty cable, reducing the time spent searching for the faulty cable, allowing for quick repairs, shortening power outages, and minimizing the impact on rail transit operations. 4) Preventing misoperation: Clear and unambiguous identification marks can effectively prevent maintenance personnel from making incorrect operations due to misidentification of cables, thereby improving the safety and accuracy of maintenance work and ensuring the stable operation of the rail transit signal system.

[0018] The features and advantages of the present invention will be described in detail through embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of the present invention; Figure 2 yes Figure 1 Enlarged schematic diagram of the cable core.

[0020] Numbers in the figure: 1-cable core; 2-oxygen-free copper conductor; 3-insulation layer; 301-inner skin layer; 302-middle foam layer; 303-outer skin layer; 4-insulated single wire; 5-quadruple wire group; 6-copper tape shielding layer; 7-tape layer; 701-polyester tape; 702-low-smoke halogen-free flame retardant tape; 8-thermal insulation protective layer; 9-aluminum sheath; 10-inner lining layer; 11-armor layer; 12-oxygen insulation layer; 13-outer sheath layer; 14-identification strip. DETAILED DESCRIPTION

[0021] Example 1: See Figure 1 and Figure 2 The present invention provides a weather-resistant and easy-to-identify new type rail transit railway digital signal cable and a preparation method thereof, comprising a cable core 1 and a protective layer wrapped around the cable core 1, characterized in that: the cable core 1 includes at least one set of quad-wire groups 5, the quad-wire group 5 is twisted by four insulated single wires 4, and the insulated single wires 4 include, from the inside to the outside, an oxygen-free copper conductor 2 and an insulating layer 3; the protective layer is wrapped around the outside of the cable core 1, and the protective layer includes, from the inside to the outside, a tape layer 7, a thermal insulation protective layer 8, an aluminum sheath 9, an inner lining layer 10, an armor layer 11, an oxygen barrier layer 12 and an outer sheath layer 13, and the identification strip 14 is located on the outside of the outer sheath layer 13.

[0022] Preferably, the cable core 1 further includes a copper tape shielding layer 6, the copper tape shielding layer 6 longitudinally covers the quad group 5, the quad group 5 is star-shaped and symmetrical, and the thickness of the quad group 5 is controlled at 90 to 290 mm; the insulating layer 3 includes an inner cortex 301, an intermediate foaming layer 302 and an outer cortex 303 from the inside to the outside, the thickness of the inner cortex 301 is controlled at 0.012 to 0.015 mm, and the thickness of the outer cortex 303 is controlled at 0.15 to 0.20 mm; the wrapping layer 7 includes a polyester tape 701 and a low-smoke halogen-free flame retardant tape 702, the low-smoke halogen-free flame retardant tape 702 is located on the outside of the low-smoke halogen-free flame retardant tape 702; the thermal insulation protective layer 8 is coated on the outside of the tape layer 7, and the thickness is controlled at 0.72~0.88mm; the aluminum protective layer 9 is longitudinally coated on the outside of the thermal insulation protective layer 8, and the thickness of the aluminum protective layer 9 is ≥1.2mm; the inner lining layer 10 is extruded on the outer surface of the aluminum protective layer 9, and the thickness of the inner lining layer 10 is controlled at 1.0~1.2mm; the thickness of the outer sheath layer 13 is controlled at 1.8~2.2mm, the width of the identification strip 14 is controlled at 6~10mm, and the thickness of the identification strip 14 is controlled at 0.1~0.3mm.

[0023] To achieve the above object, the present invention also proposes a method for preparing a new type of weather-resistant and easy-to-identify rail transit railway digital signal cable, comprising the following steps: a) Preparation of Insulated Single Wire: A single solid oxygen-free copper conductor 1 that has undergone annealing is then coated with an insulating layer 3 to form an insulated single wire 4. The insulating layer 3 comprises an inner layer 301 made of a fire-resistant solid polypropylene insulating material, an intermediate foamed layer 302 made of a polypropylene foamed insulating material, and an outer layer 303 made of a flame-retardant polyethylene insulating material. b) Cable core preparation: a plurality of insulated single wires 4 are twisted symmetrically in a star shape to form a quad 5. A copper tape shield 6 is selectively longitudinally covered on the outside of the quad 5. The prepared quad 5 and copper tape shield 6 are twisted into a cable core 1 according to a color sequence and a regular twist pitch. c) Preparation of the tape layer: Wrap the cable core 1 with a layer of polyester tape 701 and a layer of low-smoke halogen-free flame retardant tape 702; d) Preparation of thermal insulation protective layer: low-density polyethylene sheath material is used to extrude and coat the outer side of the tape layer 7; e) Aluminum sheath preparation: Aluminum strips are longitudinally coated and welded to form a highly flame-retardant polyolefin sheath material, which is then extruded onto the outer surface of the aluminum sheath using an extruder with a high compression ratio to form an inner lining aluminum sheath 9; f) Preparation of inner lining layer: A highly flame-retardant polyolefin sheath material is extruded onto the outer surface of the aluminum sheath 9 through an extruder with a high compression ratio to form an inner lining layer 10; g) Armor layer preparation: Galvanized steel strips are used for double-layer interstitial wrapping, with the steel strips tightly fitted together to form the armor layer 11; h) Preparation of oxygen barrier layer: A flame-retardant glass fiber oxygen barrier layer is wrapped around the armor layer 11 to form an oxygen barrier layer 12; i) Preparation of outer sheath layer and identification strip: The outer sheath layer 13 adopts a new type of weather-resistant and flame-retardant sheath material, and the identification strip 14 is extruded together with the outer sheath layer 13.

[0024] In this embodiment, the cable core 1 includes a group of four wire groups 5, which are composed of four insulated single wires 4 twisted in a star shape, and the thickness is controlled at 90mm; the insulation layer 3 adopts a three-layer physical foaming technology of skin-foam-skin, the inner layer 301 is a fire-resistant polypropylene solid core insulation material with a thickness of 0.012mm, the middle foaming layer 302 is a polypropylene foam insulation material, and the outer layer 303 is a flame-retardant polyethylene insulation material with a thickness of 0.15mm; the thermal insulation protective layer 8 is extruded from a low-density polyethylene sheath material with a thickness of 0.72mm; the aluminum sheath 9 is 1.2mm thick; the inner lining layer 10 is 1.0mm thick and is extruded from a highly flame-retardant polyolefin sheath material outside the aluminum sheath; the outer sheath layer 13 is 1.8mm thick and adopts a new weather-resistant flame-retardant sheath material. The outer identification strip 14 is 6mm wide and 0.10mm thick. It is extruded together with the outer sheath layer and the color is set to red for easy identification.

[0025] The cable of this embodiment has a compact structure, and the thickness of each layer is precisely controlled. While ensuring signal transmission performance, it has good weather resistance and easy identification. The special structure and material of the insulating layer 3 improve the insulation performance and flame retardancy. The multi-layer design of the protective layer enhances the mechanical protection and electromagnetic shielding effect, and adapts to the signal transmission requirements under general environmental conditions in rail transit. It is suitable for use in urban light rail, subway and other rail transit lines, and is laid in indoor stations, vehicle depots and other places with relatively good environmental conditions and moderate requirements for mechanical strength and weather resistance. It is used to transmit train control signals, communication signals, etc. to ensure signal stability and safety.

[0026] Example 2: This embodiment is basically the same as Example 1, except that: the thickness of the quad group 5 is set to 150 mm, the thickness of the inner layer 301 of the insulation layer 3 is set to 0.013 mm, and the thickness of the outer layer 303 is set to 0.18 mm; the thickness of the thermal insulation protection layer 8 is set to 0.8 mm, and the thickness of the aluminum sheath 9 is set to 1.5 mm to enhance electromagnetic shielding; the thickness of the inner lining layer 10 is set to 1.1 mm, and the thickness of the outer sheath layer 13 is set to 2.0 mm, which has strong weather resistance; the width of the identification strip 14 is set to 8 mm and the thickness is set to 0.15 mm.

[0027] In this embodiment, the thickness of each layer of the cable is appropriately increased, and the thicker outer sheath layer has excellent weather resistance, further enhancing the mechanical strength and electromagnetic shielding capability, and can better cope with complex environments, facilitating rapid identification of cables during construction and maintenance; it is suitable for use in suburban railways, intercity railways and other lines, some sections of which may face more complex natural environments, such as large temperature differences, high humidity or slightly corrosive gases, etc. At the same time, higher requirements are placed on the capacity and reliability of signal transmission, such as for transmitting multi-system composite signals of trains and connection signals of communication base stations along the line.

[0028] Example 3: This embodiment is basically the same as Example 1, except that: the thickness of the quad group 5 is set to 290 mm, the thickness of the inner layer 301 of the insulation layer 3 is set to 0.015 mm, the thickness of the outer layer 303 is set to 0.20 mm, the thickness of the thermal insulation protection layer 8 is set to 0.88 mm, providing strong thermal insulation protection; the thickness of the aluminum protective layer 9 is set to 2.0 mm, and the electromagnetic shielding effect is significant; the thickness of the inner lining layer 10 is set to 1.2 mm; the thickness of the outer sheath layer 13 is set to 2.2 mm, and the weather resistance is excellent; the width of the identification strip 14 is set to 10 mm and the thickness is set to 0.15 mm.

[0029] In this embodiment, the cable has a larger signal transmission capacity and can meet the needs of simultaneous transmission of a large number of signals; each layer reaches the maximum thickness, and the weather resistance, mechanical strength and electromagnetic shielding capability reach the optimal state, and can operate stably for a long time under harsh environmental conditions. The identification strips are highly conspicuous, which greatly facilitates identification and maintenance work in complex environments; it is suitable for high-speed railways, heavy-load railways and other lines with extremely high signal transmission requirements, and is used to transmit high-speed control signals, safety monitoring signals and large amounts of communication data of trains, etc., to ensure the efficiency and safety of railway transportation.

[0030] Working principle: The cable core 1 is the core part of the signal transmission, which is composed of a quad group 5 and a copper tape shielding layer 6. Each quad group 5 contains four insulated single wires 4, which are arranged in a star-shaped symmetrical twisted manner. This twisting method helps to reduce electromagnetic interference during signal transmission and improve the transmission quality of the signal. The oxygen-free copper conductor 2 in the insulated single wire 4 has good electrical conductivity and can effectively conduct electrical signals. The insulation layer 3 adopts a three-layer physical foaming technology of skin-foam-skin. This structure not only ensures insulation performance, but also reduces the loss during signal transmission, ensuring that the signal can be transmitted efficiently and stably. The tape layer 7 includes a polyester tape 701 and a low-smoke halogen-free flame retardant tape 702. The cable core 1 is first wrapped with a polyester tape 701 to provide preliminary protection. The low-smoke halogen-free flame retardant tape 702 on the outside further enhances the flame retardant properties of the cable. It also provides a certain degree of moisture-proof and dust-proof properties, preventing external impurities from entering the cable core and affecting signal transmission. The thermal insulation layer 8 is extruded on the outside of the tape layer 7. It can effectively isolate the external heat from the cable core 1, protecting the cable core 1 from normal operation in a high-temperature environment and avoiding degradation of signal transmission performance or failure due to excessive temperature. The aluminum sheath 9 is longitudinally wrapped on the outside of the thermal insulation layer 8. The aluminum sheath 9 not only has good electromagnetic shielding properties, but can also effectively prevent external electromagnetic interference from entering the cable core 1. It can also prevent signal leakage inside the cable core 1, ensuring the integrity and accuracy of signal transmission; at the same time, the aluminum sheath 9 also has a certain mechanical protection effect, and can withstand a certain degree of external force impact and extrusion; the inner lining layer 10 is extruded on the outer surface of the aluminum sheath 9, and it is made of highly flame-retardant polyolefin sheath material, which further improves the flame retardant performance of the cable, so that the cable can maintain a certain integrity in emergency situations such as fire, buying time for personnel evacuation and fire fighting; the armor layer 11 is wrapped with a double layer of galvanized steel belts, and the steel belts are tightly fitted to form a solid armor structure, which can effectively resist external mechanical damage, such as extrusion, stretching, impact, etc., and protect the internal structure of the cable from The fireproof layer 12 is made of flame-retardant glass fiber material and is coated on the outside of the armor layer 11, which can effectively prevent oxygen from entering the inside of the cable, thereby reducing the possibility of cable combustion and further enhancing the fire safety of the cable; the identification strip 14 is located on the outside of the outer sheath layer 13 and is extruded together with the outer sheath layer 13; the color, width and thickness of the identification strip 14 can be designed according to different needs to form an obvious mark on the appearance of the cable, which is convenient for quickly identifying the cable model, specification, direction and other information during construction and maintenance, thereby improving work efficiency and reducing the risk of misoperation.

[0031] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention falls within the protection scope of the present invention.

Claims

1. A weather-resistant and easy-to-identify new type rail transit railway digital signal cable, comprising a cable core (1) and a protective layer wrapping the cable core (1), characterized in that: The cable core (1) comprises at least one quad-wire group (5), wherein the quad-wire group (5) is formed by twisting four insulated single wires (4), wherein the insulated single wires (4) comprise, from the inside out, an oxygen-free copper conductor (2) and an insulating layer (3); the protective layer is wrapped around the outside of the cable core (1), wherein the protective layer comprises, from the inside out, a tape layer (7), a heat-insulating protective layer (8), an aluminum protective layer (9), an inner lining layer (10), an armor layer (11), an oxygen-isolating layer (12), and an outer sheath layer (13), and the identification strip (14) is located outside the outer sheath layer (13).

2. A weather-resistant and easily identifiable new type rail transit railway digital signal cable according to claim 1, characterized in that: The cable core (1) further comprises a copper tape shielding layer (6), wherein the copper tape shielding layer (6) longitudinally covers the quad-wire group (5), the quad-wire group (5) is star-shaped and symmetrical, and the thickness of the quad-wire group (5) is controlled to be 90 to 290 mm.

3. The weather-resistant and easily identifiable new type rail transit railway digital signal cable according to claim 1, characterized in that: The insulating layer (3) comprises, from the inside to the outside, an inner skin layer (301), an intermediate foaming layer (302), and an outer skin layer (303); the thickness of the inner skin layer (301) is controlled to be 0.012-0.015 mm, and the thickness of the outer skin layer (303) is controlled to be 0.15-0.20 mm.

4. The weather-resistant and easily identifiable new type rail transit railway digital signal cable according to claim 1, characterized in that: The wrapping layer (7) comprises a polyester tape (701) and a low-smoke halogen-free flame-retardant tape (702), wherein the low-smoke halogen-free flame-retardant tape (702) is located outside the low-smoke halogen-free flame-retardant tape (702).

5. The weather-resistant and easily identifiable new type rail transit railway digital signal cable according to claim 1, characterized in that: The heat-insulating protective layer (8) is coated on the outside of the wrapping layer (7), and the thickness is controlled to be 0.72-0.88 mm.

6. The weather-resistant and easily identifiable new type rail transit railway digital signal cable according to claim 1, characterized in that: The aluminum protective layer (9) is longitudinally coated on the outside of the thermal insulation protective layer (8), and the thickness of the aluminum protective layer (9) is ≥1.2 mm.

7. The weather-resistant and easily identifiable new type rail transit railway digital signal cable according to claim 1, characterized in that: The inner lining layer (10) is extruded onto the outer surface of the aluminum protective layer (9), and the thickness of the inner lining layer (10) is controlled to be 1.0 to 1.2 mm.

8. A weather-resistant and easily identifiable new type rail transit railway digital signal cable according to any one of claims 1 to 7, characterized in that: The thickness of the outer sheath layer (13) is controlled to be 1.8 to 2.2 mm, the width of the identification strip (14) is controlled to be 6 to 10 mm, and the thickness of the identification strip (14) is controlled to be 0.10 to 0.3 mm.

9. A method for preparing a new type of weather-resistant and easily identifiable rail transit railway digital signal cable, characterized by: The following steps are involved: a) Preparation of an insulated single wire: a single solid oxygen-free copper conductor (1) that has been annealed is used, and then an insulating layer (3) is coated on the surface of the oxygen-free copper conductor (1) to form an insulated single wire (4); the inner skin layer (301) of the insulating layer (3) is made of a fire-resistant polypropylene solid core insulating material, the middle foaming layer (302) is made of a polypropylene foaming insulating material, and the outer skin layer (303) is made of a flame-retardant polyethylene insulating material; b) Cable core preparation: twisting a number of insulated single wires (4) in a star-shaped symmetrical position to form a four-wire group (5), selectively corrugating the outer side of the four-wire group (5) with a copper tape shielding layer (6) longitudinally, and twisting the prepared four-wire group (5) and the copper tape shielding layer (6) into a cable core (1) according to a color sequence and a regular twisting pitch; c) Preparation of the tape layer: wrapping the cable core (1) with a layer of polyester tape (701) and a layer of low-smoke halogen-free flame retardant tape (702); d) Preparation of thermal insulation protective layer: using low-density polyethylene sheath material, extruding and coating the outer side of the tape layer (7); e) Preparation of aluminum sheath: Aluminum strips are longitudinally coated and welded to form a highly flame-retardant polyolefin sheath material, which is then extruded on the outer surface of the aluminum sheath by an extruder with a high compression ratio to form an inner lining aluminum sheath (9); f) Preparation of inner lining layer: using highly flame-retardant polyolefin sheath material, extruding it onto the outer surface of the aluminum sheath (9) through an extruder with a large compression ratio to form an inner lining layer (10); g) Armour layer preparation: Galvanised steel strips are used for double-layer gap wrapping, with the steel strips tightly fitted together to form the armour layer (11); h) Preparation of oxygen barrier layer: wrapping the armor layer (11) with a flame retardant glass fiber oxygen barrier layer to form an oxygen barrier layer (12); i) Preparation of outer sheath layer and identification strip: The outer sheath layer (13) adopts a new type of weather-resistant flame-retardant sheath material, and the identification strip (14) is extruded together with the outer sheath layer (13).

10. The method for preparing a weather-resistant and easily identifiable new type rail transit railway digital signal cable according to claim 9, characterized in that: The insulating layer (3) adopts a skin-foam-skin three-layer physical foaming technology.

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