High-temperature optical fiber cable for aircraft and preparation method therefor

Abstract

The present invention relates to the technical field of aerospace optical fiber cables, and in particular to a high-temperature optical fiber cable for an aircraft and a preparation method therefor. The high-temperature optical fiber cable comprises a high-temperature optical fiber, a stainless steel loose protective tube, a fiber braided reinforcing member, and a high-temperature-resistant polymer sheath; the stainless steel loose protective tube is sleeved on the high-temperature optical fiber; the fiber braided reinforcing member is sleeved on the stainless steel loose protective tube; and the high-temperature-resistant polymer sheath is sleeved on the fiber braided reinforcing member. In the technical solution of the present invention, the temperature resistance level of an aerospace optical fiber cable can be increased to 300°C, and the product has a small structural size and light weight and has use characteristics such as good tensile resistance, compressive resistance, and bending resistance.

Description

A high-temperature optical cable for aircraft and its preparation method Technical Field

[0001] This invention relates to the field of aviation optical cable technology, and in particular to a high-temperature optical cable for aircraft and its preparation method. Background Technology

[0002] Aviation-grade optical cables possess extremely high reliability and stability, enabling them to operate normally in harsh environments such as extreme temperatures and high humidity. Secondly, they offer excellent transmission performance, achieving high-speed, high-capacity data transmission to meet the aviation industry's demands for real-time, high-definition image transmission. Furthermore, aviation-grade optical cables are small in size, lightweight, and easy to install, making them widely used in aircraft. With continuous technological advancements, the aviation industry's demands for efficient, safe, and reliable electromechanical equipment are increasing. Against this backdrop, the upgrading and replacement of aviation-grade optical cables is particularly important. Technical issues

[0003] Currently, high-speed technology is a crucial technology for aircraft, and countries around the world are placing great emphasis on it amidst rapid development in the aviation sector. When speeds exceed Mach 2.5, aerodynamic heating occurs due to friction between gas molecules, causing the surface temperature of the aircraft to rise to 250°C–300°C. This poses a significant challenge to the temperature resistance of aircraft structural materials. Existing aviation optical cables weigh ≤5g / m and have a diameter ≤2.0mm. Due to material limitations, their temperature resistance is only -55°C to 130°C, making them unsuitable for use in hypersonic aircraft where temperatures can reach 250°C–300°C.

[0004] Therefore, how to improve the temperature resistance of optical cables for aviation so that they can be used in hypersonic aircraft has become a technical problem that urgently needs to be solved by those skilled in the art. Technical solutions

[0005] This invention provides a high-temperature optical cable for aircraft and its preparation method, which aims to improve the temperature resistance of optical cables for aircraft so that they can be used in hypersonic aircraft.

[0006] This invention provides a high-temperature optical cable for aircraft and a method for manufacturing the same, comprising:

[0007] High-temperature optical fiber;

[0008] A stainless steel loose-sleeve protective tube is sleeved on the high-temperature optical fiber.

[0009] A fiber braided reinforcement, which is sleeved on the stainless steel loose-sleeve protective tube;

[0010] High-temperature resistant polymer sheath; the high-temperature resistant polymer sheath is fitted onto the fiber braided reinforcement.

[0011] In some embodiments, the high-temperature optical fiber comprises:

[0012] Fiber core;

[0013] Cladding; the cladding is fitted onto the fiber core;

[0014] A coating layer; the coating layer is applied to the outer surface of the cladding.

[0015] In some of these embodiments, the stainless steel loose-sleeve protective tube is spiral in shape.

[0016] In some of these embodiments, the high-temperature optical fiber has a diameter of 155 μm ± 5 μm.

[0017] A method for manufacturing a high-temperature optical cable for aircraft includes the following steps:

[0018] S1. Using a CNC armored hose machine, stainless steel wire is flattened and shaped into a stainless steel strip through a mold, forming a spiral shape to create a stainless steel loose sleeve protective tube. High-temperature optical fiber is threaded to the center of the CNC armored hose machine and bonded to the stainless steel loose sleeve protective tube. Then, the high-temperature optical fiber is gradually introduced and bonded.

[0019] S2. Using a braiding machine, weave polyimide aramid to form a fiber braided reinforcement and fit it onto a stainless steel loose-sleeve protective tube.

[0020] S3. ECA material is extruded through a high-temperature extruder to form a high-temperature resistant polymer sheath;

[0021] S4. The process is completed by using a high-temperature oven to allow the internal crystals of the ECA high-temperature resistant polymer sheath to form epitaxial co-crystallization.

[0022] In some embodiments, in step S1, the high-temperature optical fiber is placed into the high-temperature optical fiber pay-off frame, a roll of stainless steel wire with a diameter of 0.55mm is installed into the stainless steel wire mounting tray, a flattening mold and a forming mold are installed, the protective cover is closed, the electrical control switch of the equipment is turned on, the equipment is turned on, and when the stainless steel loose-tube protective tube is processed to 0.5 meters, the equipment is turned off, the protective cover is opened, and the high-temperature optical fiber is inserted from the pay-off frame through the central conduit into the stainless steel loose-tube protective tube, with the head of the high-temperature optical fiber bonded to the stainless steel loose-tube protective tube. Then the equipment is turned on, and the high-temperature optical fiber is gradually brought into the interior of the protective tube as it is processed, completing the processing of the stainless steel loose-tube protective tube.

[0023] In some embodiments, polyimide fibers are stranded onto spindles, which are then mounted onto a braiding machine. In step S2, the polyimide fibers are drawn from the spindles, passed through tension control guide rollers, and led out from the thread groove, and fixed to the braiding point. Each spindle is threaded and fixed with polyimide fibers in the manner described above. After fixing, the braiding machine is started, with the upper spindle rotating clockwise and the lower spindle rotating counterclockwise to process the polyimide fibers into a braided sleeve. After braiding a section, the equipment is stopped, a braiding mold is used, and the mold base is installed. A stainless steel loose sleeve protective tube is threaded from below to the braiding point. As the polyimide fiber sleeve is braided, the stainless steel loose sleeve protective tube is brought into the fiber sleeve, completing the braiding action of the fiber braided reinforcement.

[0024] In some of these embodiments, the polyimide fiber used is 400 dtex, the weaving angle is less than 45°, and the weaving tension is 3N to 4N.

[0025] In some of the embodiments, in step S3, the ECA material is extruded with a sheath. The equipment used for sheath extrusion is a high-temperature extruder, with the maximum temperature of the extruder set to 380°C to 400°C, the extrusion speed to 5 m / min to 20 m / min, and the cooling method to be staged cooling.

[0026] In some embodiments, in step S4, the processing temperature is 280°C to 310°C and the processing time is 120 hours. Beneficial effects

[0027] The beneficial effects of this invention are as follows: By using existing high-temperature materials and through the structural design of this invention, the temperature resistance of the optical cable is improved, the outer diameter is reduced, and it is more suitable for high-temperature applications in the aerospace field. Stainless steel wire is deformed by extrusion and formed into a stainless steel loose-tube protective tube through a forming mold; a reinforcing member is formed by weaving polyimide fibers; a sheath is formed by high-temperature extrusion; and the sheath is further processed through post-processing to form an epitaxial eutectic structure, ensuring long-term stable operation of the optical cable under high-temperature conditions. This invention allows the temperature resistance of aerospace optical cables to be increased to 300℃, with a small product size, light weight, and good tensile, compressive, and bending resistance. Attached Figure Description

[0028] Figure 1 is a structural schematic diagram of a high-temperature optical cable for aircraft according to the present invention.

[0029] Figure 2 is a schematic flowchart of a method for preparing a high-temperature optical cable for aircraft according to the present invention.

[0030] Figure 3 is a schematic diagram of the structure of the CNC armored flexible tube machine in the high-temperature optical cable for aircraft and its preparation method of the present invention.

[0031] Figure 4 is a schematic diagram of the braiding machine in the high-temperature optical cable for aircraft and its preparation method of the present invention.

[0032] In the attached diagram, 1 is the fiber core; 2 is the cladding; 3 is the coating layer; 4 is the stainless steel loose-sleeve protective tube; 5 is the fiber braided reinforcement; 6 is the high-temperature resistant polymer sheath; 7 is the CNC armored flexible hose machine; 71 is the high-temperature fiber optic cable laying frame; 72 is the equipment base; 73 is the equipment electrical control switch; 74 is the flattening and forming mold; 75 is the protective cover; 76 is the stainless steel wire mounting plate; 77 is the cable outlet hole; 8 is the braiding machine; 81 is the upper spindle of the braiding machine; 82 is the lower spindle of the braiding machine; 83 is the lower spindle baffle; 84 is the slide rail base; 85 is the cable guide groove; 86 is the mold base; 87 is the braiding mold; and 88 is the polyimide fiber. The best embodiment of the present invention

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Currently, high-speed technology is a crucial technology for aircraft, and countries worldwide place great emphasis on it amidst rapid development in the aviation field. When speeds exceed Mach 2.5, aerodynamic heating occurs due to friction between gas molecules, causing the surface temperature of the aircraft to rise to 250°C–300°C. This poses a significant challenge to the temperature resistance of aircraft structural materials. Existing aviation optical cables weigh ≤5g / m and have a diameter ≤2.0mm. Due to material limitations, their temperature resistance is limited to -55°C to 130°C, making them unsuitable for use in hypersonic aircraft where temperatures can reach 250°C–300°C. Therefore, improving the temperature resistance of aviation optical cables to enable their application in hypersonic aircraft has become a pressing technical problem for those skilled in the art.

[0035] To solve the above problems, referring to Figures 1, 2, 3 and 4, the present invention provides high-temperature optical fiber;

[0036] Stainless steel loose-sleeve protective tube 4, which is sleeved on the high-temperature optical fiber;

[0037] Fiber braided reinforcement 5, which is sleeved on the stainless steel loose-sleeve protective tube 4;

[0038] High-temperature resistant polymer sheath 6; the high-temperature resistant polymer sheath 6 is sleeved on the fiber braided reinforcement 5;

[0039] Preferably, the high-temperature optical fiber comprises:

[0040] Core 1;

[0041] Cladding 2; the cladding 2 is sleeved on the fiber core 1;

[0042] Coating layer 3; the coating layer 3 is coated on the outer surface of the cladding layer 2;

[0043] Specifically, the core 1 and cladding 2 are made of silicon dioxide, the coating layer 3 is made of polyimide, the stainless steel loose-sleeve protective tube 4 is made of stainless steel, the fiber braided reinforcement 5 is made of polyimide fiber 88, and the high-temperature resistant polymer sheath 6 is made of high-temperature resistant fluoroplastic polymer (ECA), which is a composite of PTFE and PFA.

[0044] Preferably, the stainless steel loose-sleeve protective tube 4 is spiral in shape.

[0045] Preferably, the diameter of the high-temperature optical fiber is 155μm±5μm;

[0046] Specifically, the operating temperature is -65℃ to 300℃, the bending radius is 9mm, the maximum working height is 28000m, the weight is less than 5g / m, and the diameter is less than 1.8mm.

[0047] A method for manufacturing a high-temperature optical cable for aircraft includes the following steps:

[0048] S1. Using a CNC armored hose machine 7, stainless steel wire is flattened and shaped into a stainless steel strip through a mold, forming a spiral shape to form a stainless steel loose sleeve protective tube 4. High-temperature optical fiber is threaded to the center of the CNC armored hose machine 7 and bonded to the stainless steel loose sleeve protective tube 4. Then, the high-temperature optical fiber is gradually brought in and bonded.

[0049] S2. Using a braiding machine 8, weave polyimide aramid to form a fiber braided reinforcement 5 and sleeve it on the stainless steel loose-sleeve protective tube 4.

[0050] S3. ECA material is extruded through a high-temperature extruder to form a high-temperature resistant polymer sheath 6;

[0051] S4. The process is completed by using a high-temperature oven to allow the internal crystals of the ECA high-temperature resistant polymer sheath 6 to form epitaxial co-crystallization.

[0052] Preferably, in step S1, the high-temperature optical fiber is placed into the high-temperature optical fiber pay-off frame 71, a roll of stainless steel wire with a diameter of 0.55mm is installed into the stainless steel wire mounting tray 76, the flattening mold and the forming mold 74 are installed, the protective cover 75 is closed, the equipment electrical control switch 73 is turned on, the equipment is started, and when the stainless steel loose-sleeve protective tube 4 is processed to 0.5 meters, the equipment is turned off, the protective cover 75 is opened, and the high-temperature optical fiber is inserted from the pay-off frame 71 through the central conduit into the stainless steel loose-sleeve protective tube 4, and the head of the high-temperature optical fiber is bonded to the stainless steel loose-sleeve protective tube 4. Then the equipment is turned on, and the high-temperature optical fiber is gradually brought into the interior of the protective tube as it is processed, completing the processing of the stainless steel loose-sleeve protective tube. The high-temperature optical fiber pay-off frame 71, the flattening and forming mold 74, the protective cover 75 and the stainless steel wire mounting tray 76 are all installed on the equipment base 72, the equipment electrical control switch 73 is used to control the start and stop of the equipment, and the outlet hole 77 is opened at the output end of the equipment.

[0053] Specifically, the stainless steel loose-sleeve protective tube 4 is made of stainless steel wire with a diameter of 0.55mm, flattened into a stainless steel strip with a width of 0.6mm and a thickness of 0.16mm. After being processed into a spiral shape, the pitch is 0.74mm, the diameter of the spiral tube is 0.6mm±0.02mm, and the inner diameter is 0.28mm±0.02mm.

[0054] Preferably, in step S2, the polyimide fibers 88 are stranded onto the spindle, the spindle is installed on the braiding machine 8, the polyimide fibers 88 are drawn out from the spindle, pass through the tension control guide wheel, and are drawn out from the thread groove 85 and fixed to the braiding point; each spindle is threaded and fixed with polyimide fibers 88 in the above manner. After fixing, the braiding machine 8 is turned on, the upper spindle 81 rotates clockwise, and the lower spindle 82 rotates counterclockwise to process the polyimide fibers 88 into a braided sleeve. After braiding a section, the equipment is stopped, the braiding mold 87 is installed into the mold base 86, and the stainless steel loose sleeve protective tube 4 is threaded from below to the braiding point. As the polyimide fiber sleeve is braided, the stainless steel loose sleeve protective tube 4 is brought into the fiber sleeve to complete the braiding action of the fiber braided reinforcement 5.

[0055] Specifically, after processing, the stainless steel loose sleeve protective tube 4 should avoid the accumulation of stress in its spiral. The semi-finished product after processing should fall naturally into a cylindrical container. When the reinforcing member 5 is braided, the semi-finished product of the stainless steel loose sleeve protective tube 4 is directly released from the cylindrical container to release the torque and avoid the presence of torsional force in the optical cable. The grade of the stainless steel material is 204L. A lower spindle baffle 83 is provided on one side of the lower spindle 82 of the braiding machine, and the slide rail base is circumferentially located on the outside of the upper spindle 81 of the braiding machine.

[0056] Preferably, the polyimide fiber used is 400dtex, the weaving angle is less than 45°, and the weaving tension is 3N to 4N.

[0057] Preferably, in step S3, the ECA material is extruded into a sheath 6. The equipment used for extruding the sheath 6 is a high-temperature extruder, with the maximum temperature of the extruder set to 380℃~400℃, the extrusion speed to 5m / min~20m / min, and the cooling method to be staged cooling.

[0058] Specifically, the cooling equipment used is a heating furnace with four temperature sections: 250℃, 200℃, 150℃, and 100℃. Each cooling section is 2 meters long, completing the primary crystallization of the sheath material 6.

[0059] Preferably, in step S4, the processing temperature is 280℃~310℃ and the processing time is 120h;

[0060] Specifically, the optical cable, extruded from the sheath, is subjected to a certain tension and rewound onto an aluminum alloy reel. The reel is then placed in a high-temperature oven, set at 280℃~310℃ for 120 hours. After the time is up, the heating function of the high-temperature oven is turned off, and the internal temperature of the oven is allowed to slowly drop to room temperature before the optical cable is removed for post-processing. This step involves a certain tensile force within the optical cable at high temperatures, ensuring that the sheath remains dimensionally stable and does not shrink under these conditions. Simultaneously, under high temperatures, PFA molecules tightly coat the PTFE crystals, forming an epitaxial co-crystallization. Slow cooling is used to improve the stability of this epitaxial co-crystallization.

[0061] In another embodiment, the selected high-temperature optical fiber has a core diameter of 9 μm, a cladding diameter of 125 μm, a coating diameter of 155 μm, and a transmission attenuation of 1.0 dB / km@1310 nm and 0.8 dB / km@1550 nm; the specific operation is as follows:

[0062] (1) Processing of stainless steel loose tube protective tube 4: The semi-finished high-temperature optical fiber is placed into the high-temperature optical fiber pay-off frame 71. The whole roll of stainless steel wire with a diameter of 0.55mm is installed into the stainless steel wire installation tray 76. The gap of the flattening mold is selected as 0.16mm, and the inner diameter of the forming mold 74 is selected as 0.605mm. The flattening mold and the forming mold 74 are installed. The rotation speed of the stainless steel flexible tube processing equipment is set to 100r / min and the pitch is 0.74mm. When the stainless steel loose tube protective tube 4 is processed to 0.5m, the equipment is turned off, the protective cover 75 is opened, and the high-temperature optical fiber is inserted from the pay-off frame 71 through the central conduit into the stainless steel loose tube protective tube 4. The head of the high-temperature optical fiber is bonded to the stainless steel loose tube protective tube 4. A stainless steel bucket with a diameter of 500mm is placed at the outlet. Then the equipment is turned on to complete the processing of the stainless steel loose tube protective tube.

[0063] (2) Processing of fiber braided reinforcement 5: Using a spinning machine, 400dtex polyimide fiber 88 is wound onto a spindle. A 24-spindle braiding machine 8 is used, with the braiding pitch set to 12mm and the braiding angle to 20°. A handheld tension gauge is used to adjust the tension of each spindle to 3N~4N. The semi-finished product with the stainless steel loose sleeve protective tube 4 is placed under the braiding machine and the yarn is released naturally to complete the processing of fiber braided reinforcement 5.

[0064] (3) Processing of high-temperature resistant polymer sheath 6: A high-temperature extruder is used, and the high-temperature optical fiber pay-off frame 71 adopts an active pay-off method. The extruder temperatures are set to 260℃, 300℃, 330℃, 360℃, 380℃, and 390℃ respectively; the cooling zone uses a heating furnace with temperatures set to 250℃, 200℃, 150℃, and 100℃. The extrusion screw speed is 2r / min;

[0065] (4) Post-processing: The optical cable after extrusion of sheath 6 is rewound using a rewinding machine. The rewinding reel is made of aluminum alloy with a diameter of 400mm and a tension of 10N during rewinding. The rewound reel is placed in a high-temperature oven with a temperature of 300℃ and a time of 120h. Timing starts when the temperature is reached. When the time is up, the heating function of the high-temperature oven is turned off. After the internal temperature of the oven slowly drops to room temperature, the optical cable is taken out and the post-processing is completed.

[0066] In another embodiment, the selected high-temperature optical fiber has a core diameter of 50 μm, a cladding diameter of 125 μm, a coating diameter of 155 μm, and a transmission attenuation of 3.5 dB / km@850 nm and 1.5 dB / km@1300 nm. The specific operation is as follows:

[0067] (1) Processing of stainless steel loose tube protective tube 4: The semi-finished high-temperature optical fiber is placed into the high-temperature optical fiber pay-off frame 71. The whole roll of stainless steel wire with a diameter of 0.55mm is installed into the stainless steel wire installation tray 76. The gap of the flattening mold is selected as 0.16mm, and the inner diameter of the forming mold is selected as 0.605mm. The flattening mold and the forming mold 74 are installed. The rotation speed of the stainless steel hose processing equipment is set to 100r / min and the pitch is 0.74mm. When the stainless steel loose tube protective tube 4 is processed to 0.5m, the equipment is turned off, the protective cover 75 is opened, and the high-temperature optical fiber is inserted from the pay-off frame 71 through the central conduit into the stainless steel loose tube protective tube 4. The head of the high-temperature optical fiber is bonded to the stainless steel loose tube protective tube 4. A stainless steel bucket with a diameter of 500mm is placed at the outlet. Then the equipment is turned on to complete the processing of the stainless steel loose tube protective tube.

[0068] (2) Processing of fiber braided reinforcement 5: Using a spinning machine, 400dtex polyimide fiber 88 is wound onto a spindle. A 24-spindle braiding machine 8 is used, with the braiding pitch set to 12mm and the braiding angle to 20°. A handheld tension gauge is used to adjust the tension of each spindle to 3N~4N. The semi-finished product with the stainless steel loose sleeve protective tube 4 is placed under the braiding machine and the yarn is released naturally to complete the processing of fiber braided reinforcement 5;

[0069] (3) Processing of high-temperature resistant polymer sheath 6: A high-temperature extruder is used, and the high-temperature optical fiber pay-off frame 71 adopts an active pay-off method. The extruder temperatures are set to 260℃, 300℃, 330℃, 360℃, 380℃, and 390℃ respectively; the cooling zone uses a heating furnace with temperatures set to 250℃, 200℃, 150℃, and 100℃. The extrusion screw speed is 2r / min.

[0070] (4) Post-processing: The optical cable after extrusion of sheath 6 is rewound using a rewinding machine. The rewinding reel is made of aluminum alloy with a diameter of 400mm and a tension of 10N during rewinding. The rewound reel is placed in a high-temperature oven with a temperature of 300℃ and a time of 120h. Timing starts when the temperature is reached. When the time is up, the heating function of the high-temperature oven is turned off. After the internal temperature of the oven slowly drops to room temperature, the optical cable is taken out and the post-processing is completed.

[0071] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention. Industrial applicability

[0072] This invention has been implemented and has industrial applicability.

Claims

A high-temperature optical cable for aircraft, characterized in that, include: High-temperature optical fiber; Stainless steel loose sleeve protective tube (4), the stainless steel loose sleeve protective tube (4) is sleeved on the high temperature optical fiber; Fiber braided reinforcement (5), which is sleeved on the stainless steel loose sleeve protective tube (4); High-temperature resistant polymer sheath (6); the high-temperature resistant polymer sheath (6) is fitted onto the fiber braided reinforcement (5). A high-temperature optical cable for aircraft according to claim 1, characterized in that, The high-temperature optical fiber includes: Core (1); Cladding (2); the cladding (2) is fitted onto the fiber core (1); Coating layer (3); the coating layer (3) is applied to the outer surface of the cladding layer (2). A high-temperature optical cable for aircraft according to claim 2, characterized in that, The stainless steel loose-sleeve protective tube (4) is spiral in shape. A high-temperature optical cable for aircraft according to claim 3, characterized in that, The diameter of the high-temperature optical fiber is 155μm±5μm. A method for manufacturing a high-temperature optical cable for aircraft, implemented using the high-temperature optical cable for aircraft as described in any one of claims 1-4, characterized in that... Includes the following steps: S1. Using a CNC armored hose machine (7), the stainless steel wire is flattened and formed into a stainless steel strip through a mold. The shape is spiral, forming a stainless steel loose sleeve protective tube (4). The high-temperature optical fiber is threaded to the center of the CNC armored hose machine (7) and bonded to the stainless steel loose sleeve protective tube (4). Then the high-temperature optical fiber is gradually brought in and bonded. S2. Using a braiding machine (8), weave polyimide aramid to form a fiber braided reinforcement (5) and fit it onto a stainless steel loose-fitting protective tube (4); S3. ECA material is extruded through a high-temperature extruder to form a high-temperature resistant polymer sheath (6). S4. The ECA high-temperature resistant polymer sheath (6) is processed by forming epitaxial co-crystallization of internal crystals through a high-temperature oven. A method for manufacturing a high-temperature optical cable for aircraft according to claim 5, characterized in that, In step S1, the high-temperature optical fiber is placed into the high-temperature optical fiber pay-off frame (71), and a roll of stainless steel wire with a diameter of 0.55mm is installed into the stainless steel wire mounting tray (76). The flattening mold and the forming mold (74) are installed. The protective cover (75) is closed, and the equipment electrical control switch (73) is turned on. The equipment is turned on. When the stainless steel loose tube (4) is processed to 0.5 meters, the equipment is turned off, the protective cover (75) is opened, and the high-temperature optical fiber is inserted from the pay-off frame (71) through the central conduit into the stainless steel loose tube (4). The head of the high-temperature optical fiber is bonded to the stainless steel loose tube (4). Then the equipment is turned on. As the protective tube is processed, the high-temperature optical fiber is gradually brought into the inside of the protective tube, and the processing of the stainless steel loose tube (4) is completed. A high-temperature optical cable for aircraft and its preparation method according to claim 5, characterized in that, In step S2, the polyimide fiber (88) is stranded onto the spindle, the spindle is installed on the braiding machine (8), the polyimide fiber (88) is drawn out from the spindle, passes through the tension control guide wheel, and is drawn out from the wire groove (85) and fixed to the braiding point; each spindle is threaded and fixed with the polyimide fiber (88) in the above manner. After fixing, the braiding machine is turned on, the upper spindle (81) rotates clockwise, and the lower spindle (82) rotates counterclockwise. The polyimide fiber (88) is processed into a braided sleeve. After braiding a section, the equipment is stopped, the braiding mold (87) is used, the mold base (86) is installed, and the stainless steel loose sleeve protection tube (4) is threaded from below to the braiding point. As the polyimide fiber sleeve is braided, the stainless steel loose sleeve protection tube (4) is brought into the fiber sleeve, and the braiding action of the fiber braiding reinforcement (5) is completed. A high-temperature optical cable for aircraft and its preparation method according to claim 5, characterized in that, The polyimide fiber (88) used has a specification of 400dtex, a weaving angle of less than 45°, and a weaving tension of 3N to 4N. A high-temperature optical cable for aircraft and its preparation method according to claim 5, characterized in that, In step S3, the ECA material is extruded into a high-temperature resistant polymer sheath (6). The equipment used for extruding the high-temperature resistant polymer sheath (6) is a high-temperature extruder. The maximum temperature of the extruder is set to 380℃~400℃, the extrusion speed is 5m / min~20m / min, and the cooling method is step-by-step cooling. A high-temperature optical cable for aircraft and its preparation method according to claim 5, characterized in that, In step S4, the processing temperature is 280℃~310℃ and the processing time is 120h.

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