Large-section cable for vehicle end bridging

Abstract

The invention belongs to the technical field of cable manufacturing, and discloses a large-section cable for vehicle end bridging, which sequentially comprises a conductor layer, an insulating layer, a shielding layer and a sheath layer from inside to outside, the shielding layer comprises a forward winding type braided shielding wire and a reverse winding type meta-position aramid fiber, the braided shielding wire is formed by twisting a plurality of strands of metal alloy, and the sheath layer is arranged between the conductor layer and the insulating layer. The meta-position aramid fiber adopts stranded meta-position aramid fiber filaments as reverse winding weaving filaments, the sheath layer adopts high-temperature hot drying tunnel vulcanization extrusion type silicone rubber, the temperature of a high-temperature section of a drying tunnel is not lower than 400 DEG C, the vulcanization time is not less than 1 minute, and the meta-position aramid fiber is embrittled and cracked until carbonization failure due to the high temperature of the high-temperature section of the drying tunnel. The cable is suitable for production of a winding shielding layer of a large-section cable for vehicle end bridging with silicone rubber as an insulating layer and a sheath layer, and through introduction of reverse winding meta-position aramid fibers, on the basis of not influencing the use of the whole product, the product structure is further stabilized, and the use stability and safety of the product are ensured.

Description

Technical Field

[0001] The invention mainly relates to the technical field of cable manufacturing, in particular to a large-section vehicle-end jumper cable, which is suitable for the production process of the vehicle-end jumper cable with large-section using silicone rubber as the insulation layer and the sheath layer. Background Art

[0002] The special operating conditions of frequent movement of vehicle-end jumper cables determine that their flexibility is a key indicator. At the same time, based on the fact that the vehicle-end jumper power, control and communication cables are bundled together as a whole during installation and use, large-section power cables need to consider both flexibility and electromagnetic shielding during design and development. At present, the industry's large-section shielded power cables use a winding shielding method when designing the shielding layer. This design is softer than the braided shielding method. Although the shielding effect is poor, it can meet the needs of electromagnetic shielding and does not generate too much electromagnetic interference to the outside world.

[0003] At present, domestic large-section power cable products often have core breakage during use, and the insulating sheath is relatively thick due to its large cross-section and high system voltage in the application scenario. The high requirement for structural stability increases the difficulty of processing, and the one-time yield is low. At the same time, due to production costs and market demand, most winding production equipment cannot meet the production needs of large-section and large-diameter cables. Therefore, heavy-duty braiding machines are mostly used for winding production of large-section shielded cables with winding at the vehicle end. At the same time, due to the number of braiding machine spindles and the requirements of shielding effectiveness, the braiding machine spindles need to strand several shielded monofilaments to meet the design requirements. Therefore, in the production process, it is easy to cause wire jumpers and overlap, which increases the risk of wire breakage due to friction between shielding wires and uneven internal tension when the cable is frequently moved, thereby affecting the service life of the cable.

[0004] Therefore, there is an urgent need to provide a new type of large-section vehicle-end jumper cable to solve the above problems. Summary of the invention

[0005] In order to overcome the technical defects in the above-mentioned prior art, the present invention proposes a large-section vehicle-end jumper cable, especially for the production process of the winding shielding layer of the large-section vehicle-end jumper cable with silicone rubber as the insulation layer and the sheath layer, by adding reverse winding meta-aramid filaments and then invalidating them through a high-temperature processing technology of the sheath layer, thereby meeting the special operating conditions requirements of the frequent movement of the vehicle-end jumper cable and ensuring flexibility and electromagnetic shielding performance.

[0006] To achieve the above object, the present invention is achieved through the following technical solutions:

[0007] A large-section vehicle-end jumper cable comprises, from the inside to the outside, a conductor layer, an insulating layer, a shielding layer and a sheath layer, wherein the shielding layer comprises a forward-wound braided shielding wire and a reverse-wound meta-aramid, wherein the braided shielding wire is formed by twisting a plurality of metal alloy strands, wherein the meta-aramid uses stranded meta-aramid fiber filaments as reverse-wound braiding wires, and wherein the sheath layer is made of high-temperature hot oven vulcanized extruded silicone rubber, wherein the temperature of the high-temperature section of the oven is not lower than 400°C, and the vulcanization time is not less than 1 minute, and the high temperature of the high-temperature section of the oven causes the meta-aramid to become brittle, cracked, and finally carbonized and fail.

[0008] Furthermore, the conductor layer is made of a plurality of tinned copper monofilaments, which are first bundled into multiple strands, and then the strands are twisted to form the conductor layer, the number of twisted strands is 19, 37 or 61, and the strands are twisted in the same direction.

[0009] Furthermore, the strand bundle pitch ratio of the tinned copper conductor is 28-35, the outermost layer pitch ratio of the multiple twist is 9-11, and the pitch ratio increases from the outside to the inside layer by layer, and increases by 2-3 layer by layer according to the number of layers.

[0010] Furthermore, the conductor layer adopts a tungsten steel mold, and the mold sizing area is set to 38-54mm according to the cross-section of the conductor layer, and the conductor layer is shaped and twisted in a concentric pressing manner.

[0011] Furthermore, the thickness of the tinned layer of the tinned copper monofilament is not less than 0.6 μm.

[0012] Furthermore, the insulating layer uses high-temperature hot oven vulcanized extruded silicone rubber as the insulating layer, adopts a peroxide cross-linking system, the temperature of the high-temperature section of the oven is not less than 400° C., and the vulcanization time is not less than 1 minute.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The conductor monofilament is made of tinned copper monofilament, which is first bundled into multiple strands and then twisted. The special design of the processing technology changes the product's bending and torsion resistance, greatly improving the softness and service life of the cable. Compared with the same type of large-section products, the mobile laying bending radius is increased from 10 times the cable outer diameter to 5 times the cable bending radius, an increase rate of 100%, and the number of bending and torsion times is increased from 300,000 times to 1 million times, an increase rate of 333%

[0015] 2. By selecting the vulcanization system for the insulating layer and designing the production process, that is, using a peroxide cross-linking system, structural deformation caused by gravity sagging is avoided and the difficulty of the production process for this type of material is reduced, solving the problems of eccentricity and waste of production costs of similar products with large cross-sections, and increasing the yield from 60% to more than 90%.

[0016] 3. The innovative use of metal alloy materials as braided shielding wires and their special multi-strand twisted structure design improve the tensile strength and flexibility of the shielding layer, and the breaking force is increased from 48N to 270N, an increase of 563%.

[0017] 4. The production method is cleverly designed by using the characteristic of meta-aramid material itself that it will fail when exposed to high temperature. First, the forward shielding wire and reverse meta-aramid are superimposed on each other to solve the wire skipping and core breaking caused by superposition in the unidirectional winding processing products of the braiding machine. Then, the high temperature of the sheath layer processing technology is used to remove the meta-aramid introduced in the braiding process without affecting the overall performance of the product. The probability of metal shielding monofilament skipping and lamination is reduced from 30% to less than 5%. By adjusting the number of aramid spindles, the process difficulties can be 100% solved. At the same time, the spindle tension can be reduced from 70N to 30N, and the tension introduction rate is reduced by 42%, further improving the product's bending and torsion resistance. The number of bending and torsion times is increased from 300,000 times to 1 million times, an increase rate of 333%.

[0018] 5. The innovative use of universal braiding machines for winding technology solves the problem that the copper wire winding machine's excessive wire tension easily causes the composite alloy braided wire to break, and the problem that conventional small winding machines cannot reel in and unreel large-section cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention;

[0020] Figure 2 is a schematic diagram of a shielding layer of the present invention;

[0021] Among them: 1. Conductor layer; 2. Insulation layer; 3. Shielding layer; 3-1. Braided shielding wire; 3-2. Meta-aramid; 4. Sheath layer. DETAILED DESCRIPTION

[0022] The preferred mechanism and motion realization method of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments.

[0023] like Figure 1 As shown, a large-section vehicle-end jumper cable comprises a conductor layer 1, an insulating layer 2, a shielding layer 3 and a sheath layer 4 from the inside to the outside.

[0024] The conductor layer 1 comprises a plurality of tinned copper monofilaments, which are first bundled into multiple strands, and then the strands are twisted into the conductor layer 1; the tinned copper monofilaments are produced by hot-dip plating process, which can enhance the electrical performance stability of the cable during processing and under use conditions; the number of twisted strands is preferably 19, 37 or 61, and the strands are twisted in the same direction, which is different from the reverse twisting between layers of conventional products, thereby improving the overall uniformity of the conductor layer, reducing the conductor diameter as a whole, reducing the overall allowable bending radius of the product, and improving the uniformity of the interlayer tension, thereby improving the product's softness and reducing the risk of breakage, and also reducing the mutual friction frequency and friction between the strands, so as to obtain better movement resistance; the thickness of the tinned layer of the tinned copper monofilament is not less than 0.6μm, which is different from the industry's common 0.4μm, so as to improve the wear margin caused by repeated bending during multiple twisting production and use.

[0025] The bundled pitch and twisted pitch of the tinned copper conductor are specially designed to improve the bundled pitch-diameter ratio, increase the general pitch-diameter ratio of 20-25 to 28-35, and reduce the general multiple twisted pitch-diameter ratio, which is adjusted from the general outermost layer of 17-20 to the outermost layer of 9-11, gradually increasing from the outside to the inside, and increasing by 2-3 layers inward according to the number of layers. The advantages are: 1. Improving the overall flexibility of the conductor, thereby better meeting the frequent movement conditions; 2. Through the step-by-step changes of different pitch-diameter ratios, ensuring that the tension between the layers of each conductor strand is uniform and stable during movement, reducing the risk of local stress fracture caused by uneven tension.

[0026] The conductor layer 1 made of tinned copper monofilaments adopts a tungsten steel mold through design, and increases the mold sizing area to 38-54mm according to the cross-sectional area of ​​the conductor layer, and is shaped and twisted in a concentric pressing manner. That is to say, according to different conductor cross-sectional areas, the length of the mold sizing area is inconsistent, and the overall range is between 38-54. The advantages are: 1. Through the compaction mold shaping and the same-direction twisting, the gap between the strands is further reduced, the tension between the monofilaments is uniform, the movement resistance is improved, and the risk of breakage caused by local tension concentration is reduced; 2. With the overall design of the same-direction twisting and regular twisting, the conductor diameter is reduced as a whole, the overall allowable bending radius of the product is reduced, and the uniformity of the interlayer tension is improved, thereby improving the softness of the product and reducing the risk of breakage.

[0027] The insulating layer 2 includes a high-temperature hot drying oven vulcanized extruded silicone rubber as the insulating layer. The vulcanization system of the silicone rubber adopts a peroxide cross-linking system. The advantages of the peroxide cross-linking system are: (1) a medium vulcanization speed is adopted, which reduces the material waste caused by too fast or too slow vulcanization speed during the processing, thereby improving the product yield; (2) its positive vulcanization period is quite flat and long, and avoids the occurrence of persulfurization cracking and vulcanization reversion, reducing the process difficulty and improving the product yield.

[0028] The insulating layer 2 is produced by hot oven vulcanization based on the design of the above-mentioned insulating layer material and vulcanization system. The temperature of the high temperature section of the oven is not less than 400°C, and the vulcanization time is not less than 1 minute. Firstly, the high temperature hot oven vulcanization extrusion process can enable the insulating layer to obtain a sufficient and stable vulcanization process, so that the bond energy between the main chain, side chain and inorganic compounding agent of the silicone rubber is more complex and stable. The macroscopic performance is that the physical and mechanical properties, wear resistance and oil resistance are significantly improved, and the excellent weather resistance and water barrier properties are further improved. Secondly, the vulcanization process of the insulating layer is uniform and stable, and the phenomenon of uneven vulcanization is eliminated. At the same time, the high temperature rapid shaping avoids the eccentricity caused by gravity sagging of the large-section and high-thickness insulating layer when it is in a fluid state at the extrusion die mouth, thereby ensuring the stability of the insulating structure.

[0029] The shielding layer 3 includes a forward-winding braided shielding wire 3-1 and a reverse-winding meta-aramid 3-2; the shielding layer 3 is produced by a braiding machine through a winding shielding process, the metal of the braided shielding wire 3-1 is preferably made of a metal alloy twisted together, and the alloy of copper and tin is the best, and a plurality of alloy monofilaments (0.04-0.06mm) are twisted regularly and then re-twisted, and the pitch is reduced to less than 12mm, so as to finally obtain the best softness performance; the meta-aramid 3-2 is made of a strand of meta-aramid fiber filaments that are reversely wound relative to the braided shielding wire 3-1. Taking a 32-spindle walking spindle braiding machine as an example, each spindle has 4 paralleled metal monofilaments, with the right or left direction as the forward direction (the reverse direction is the reverse direction), 16 forward spindles are installed as the winding shielding layer wire 3-1, and a single reverse spindle is installed as the reverse winding braiding wire.

[0030] The forward winding braided shielding wire 3-1 adopts an alloy of copper and tin, which has high tensile strength, solves the problem of excessive stress causing breakage in frequent mobile applications, and has excellent wear resistance, which solves the problem of breakage caused by mutual friction of shielding wires during mobile use. The braided shielding wire 3-1 usually adopts a production process of first bundling and then twisting, which improves the softness of the product, makes the internal stress of the shielding layer evenly dispersed, and solves the stress concentration and breakage caused by too many movements. In the shielding layer 3 produced at room temperature, the reverse-wound meta-aramid fiber filaments will provide lateral pressure to flatten the forward braided shielding wire, prevent the metal shielding single wire from skipping and overlapping each other, and at the same time, by providing a constant pressure to balance the internal stress of the metal shielding wire, the probability of metal shielding single wire skipping and overlapping is reduced from 30% to less than 5%. By increasing the number of reverse meta-aramid wire spindles, up to 8 can completely eliminate the occurrence of skipping and overlapping. At the same time, the spindle tension can be reduced from 70N to 30N, further reducing the risk of wire breakage caused by internal stress during product use.

[0031] The sheath layer 4 adopts the same high-temperature hot oven vulcanized extruded silicone rubber as the insulating layer 2 as the sheath layer, which is extruded by an extruder and covered on the outer surface of the shielding layer 3 as the sheath layer. The temperature of the high-temperature section of the oven is not lower than 400°C, and the vulcanization time is not less than 1 minute. The high temperature of 400°C makes the meta-aramid embrittled and cracked until it carbonizes and fails.

[0032] The insulating layer 2 is first produced in a high-temperature hot drying tunnel vulcanization unit, and then the shielding layer 3 is completed. During the production process of the sheath layer 4, since the glass transition temperature of the meta-aramid fiber is 270°C, when the temperature reaches 400°C, it will greatly lose strength and gradually become brittle, carbonize and even crack, but no molten droplets will be generated. Therefore, when producing the silicone rubber sheath of the sheath layer 4, the meta-aramid will lose its effect at high temperature and will not affect the cable structure itself. Since the process is irreversible, after the cable production is completed and returns to room temperature, its residue is stable at the normal operating temperature of the cable and will not cause additional impact on the cable performance. Usually, during the frequent movement of bidirectional braided cables, repeated bending will cause the forward and reverse shielding wires to rub against each other, resulting in eventual breakage and affecting the cable performance. Although the use of general para-aramid braiding can reduce the degree of wear to a certain extent, it cannot solve the problem of mutual wear. Therefore, meta-aramid is first used to solve the production stability of the forward shielding wire, and then its high-temperature decomposition failure characteristics are used to remove the reverse braiding, ultimately obtaining a highly soft product and eliminating the problem of wear.

[0033] Therefore, without affecting the use of the overall product, the process difficulties in producing the shielding layer 3 are solved by introducing the reverse-wound meta-aramid 3-2 into the shielding layer 3. The structure of the shielding layer can be stabilized during the winding shielding process to ensure its stability. When producing the sheath layer, the reverse-wound meta-aramid 3-2 in the shielding layer 3 is rendered ineffective through high-temperature pyrolysis, thereby ensuring the stability of the product structure and the safety of use of the cable product.

[0034] Cable 120mm 2 For example, the comparison of the sheath and overall physical properties that may be affected by the method described in the present invention is shown in Table 1:

[0035] Table 1

[0036]

[0037]

[0038] The large-section vehicle-end jumper cable described in this embodiment is suitable for the winding shielding layer production process of the large-section vehicle-end jumper cable with silicone rubber as the insulation layer and the sheath layer. By adding reverse winding meta-aramid filaments and cooperating with high-temperature drying tunnel silicone rubber sheath extrusion, without affecting the use of the vehicle-end jumper cable, not only the structural stability of the winding shielding layer is improved, but also the internal stress introduced into the shielding monofilament caused by the production process is reduced, thereby reducing the risk of broken wires in the shielding layer caused by frequent movement of the vehicle-end jumper cable under operating conditions, and more stably ensuring the shielding effect of the product shielding layer. In other words, through the selection of materials and the process design of the previous and next processes, it is possible to optimize the product structure and performance at the production end, and meet the flexibility at the use end without affecting the product performance.

[0039] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A large-section vehicle-end jumper cable, characterized in that: The invention comprises, from the inside to the outside, a conductor layer (1), an insulating layer (2), a shielding layer (3) and a sheath layer (4), wherein the shielding layer (3) comprises a forward-wound braided shielding wire (3-1) and a reverse-wound meta-aramid fiber (3-2), wherein the braided shielding wire (3-1) is formed by twisting a plurality of metal alloy strands, and the meta-aramid fiber (3-2) is formed by twisting strands of meta-aramid fiber filaments as reverse-wound braiding wires, and the sheath layer (4) is formed by high-temperature hot oven vulcanized extruded silicone rubber, wherein the temperature of the high-temperature section of the oven is not less than 400° C. and the vulcanization time is not less than 1 minute, and the high temperature of the high-temperature section of the oven causes the meta-aramid fiber (3-2) to become brittle, cracked and even carbonized and ineffective.

2. A large cross-section vehicle-end jumper cable according to claim 1, characterized in that: The conductor layer (1) is made of a plurality of tinned copper monofilaments, which are first bundled into a plurality of strands, and then the strands are twisted to form the conductor layer (1). The number of twisted strands is 19, 37 or 61, and the strands are twisted in the same direction.

3. A large cross-section vehicle-end jumper cable according to claim 2, characterized in that: The strand bundle pitch diameter ratio of the tinned copper conductor is 28-35, the outermost layer pitch diameter ratio of the double-twisted strand is 9-11, and the pitch diameter ratio increases layer by layer from the outside to the inside, and increases by 2-3 layer by layer according to the number of layers.

4. A large cross-section vehicle-end jumper cable according to claim 2, characterized in that: The conductor layer (1) adopts a tungsten steel mold, and the mold sizing area is set to 38-54 mm according to the cross section of the conductor layer (1), and is shaped and twisted in a concentric pressing manner.

5. A large-section vehicle-end jumper cable according to claim 2, characterized in that: The thickness of the tinned layer of the tinned copper monofilament is not less than 0.6 μm.

6. A large cross-section vehicle-end jumper cable according to claim 1, characterized in that: The insulating layer (2) uses high-temperature hot oven vulcanized extruded silicone rubber as the insulating layer (2), adopts a peroxide cross-linking system, the temperature of the high-temperature section of the oven is not less than 400° C., and the vulcanization time is not less than 1 minute.

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