RU193843U1 - ELECTRIC FLEXIBLE CABLE - Google Patents

Abstract

The claimed utility model relates to cable technology, namely, to designs of flexible electric cables intended for unsteady laying in ground and underground conditions, as well as indoors, and connecting mobile machines, mechanisms and equipment to electric networks and to mobile sources of electric energy, including power and auxiliary circuits. The technical task of the utility model is to develop a flexible electric cable that is not inferior to the prototype in terms of basic characteristics, as well as more technological and more economical, high-quality and highly reliable, designed for non-stationary laying in any conditions. This object is achieved in that the conductive conductors are made of aluminum wires or its alloys, modified with additives from the group: iron, nickel, titanium, vanadium, chromium, manganese, magnesium, copper, zinc, boron, or mixtures thereof, including wires ductile aluminum alloys with a mesopolycrystalline structure and a grain size of not more than 150 microns. In the proposed design, the electric flexible cable contains conductive wires, a core screen, core insulation, a core insulation screen, a separation layer and a sheath. The new cable has it has improved operational characteristics and reliability, increased manufacturability and quality, increased efficiency.

Description

The utility model relates to cable technology, namely, to designs of electric flexible cables intended for non-stationary laying in ground and underground conditions, as well as indoors and connecting mobile machines, mechanisms and equipment to electric networks and to mobile sources of electric energy, including power and auxiliary circuits.

Known designs for flexible cables according to patents 51438 and 69675, Russia, consisting of copper conductive cores with rubber insulation. The conductors of these flexible cables are twisted from copper wires with a diameter of less than 0.5 mm. The disadvantages of these designs of flexible cables are their large mass and high cost, as well as the accelerated destruction of insulation under the influence of copper ions. The AKRPT brand flexible cable design is also known in accordance with GOST 13497-68, year of commissioning 1970, Russia, containing conductive wires with rubber insulation. The conductive conductors of the AKRPT flexible cable are twisted from aluminum wires with a diameter of more than 0.8 mm and have a third flexibility class according to GOST 22483-77, commissioned in 1980, Russia. In this regard, AKRPT cable belongs to the group of cables with reduced flexibility and limited scope. A smaller diameter aluminum wire is extremely difficult to produce. The tensile and bending strength of aluminum wire is significantly lower than the strength of copper wire. Aluminum and its existing alloys for electrical purposes have a reduced long-term allowable heating temperature (up to 90 ° C). At a higher heating temperature, a significant decrease in the physicomechanical characteristics of aluminum and its known alloys occurs due to an increase in grain. Aluminum wire becomes brittle. The disadvantages of the cable brand AKRPT:

- increased rigidity;

- increased creep under load;

- increased permissible bending radius;

- low resistance to repeated bends;

- low manufacturability;

- low resource and service life.

These shortcomings significantly reduce the performance, reliability, durability and scope of flexible cables with aluminum conductors. Currently, AKRPT flexible cable is discontinued.

The closest in its parameters to the proposed design is an electric flexible cable according to patent No. 133964 dated 05/13/2013, Russia, for a utility model (prototype), which contains insulated multi-wire conductive conductors of 5-6 class of flexibility from ultra-thin aluminum wires or its alloys with modifying additives having a fine-grained structure. As modifying additives for the prototype, rare and rare-earth metals from the group: zirconium, scandium, yttrium, cerium, lanthanum, vanadium, hafnium, alkali or alkaline earth metals from the group: lithium, beryllium, magnesium, calcium, strontium, or semiconductor materials can be used from the group: boron, tellurium, selenium, germanium, silicon, or mixtures thereof. The wires of the conductors of the flexible cable according to the prototype can be made of superplastic aluminum alloys with an ultrafine-grained or nanocrystalline structure obtained by physical methods of processing workpieces: by the method of intense plastic deformation and by casting an aluminum alloy in a high-frequency electromagnetic field. Currently, there are only laboratory facilities for processing aluminum alloy preforms using these methods. The use of rare and rare-earth metals as modifying additives leads to a significant increase in the cost of aluminum alloys and the complexity of the technological process for drawing ultrathin wires due to the increased stiffness of aluminum-zirconium alloys. The flexible electric cable according to the prototype (Fig.) Contains one or more main conductive conductors (conductors) 1 of ultrafine aluminum wires or its alloys with modifying additives, screen 2 along conductors of conductive elastomers or without it, insulation 3 of conductors from elastomers, screen 4 for insulation of cores from electrically conductive elastomers or without it, a separation layer 5 of polymer materials or without it, one or two-layer shell 6 of elastomers. The list of current-carrying conductors included in various brands of flexible cable according to the prototype: main (phase) conductors, zero or ground conductor, auxiliary conductors of lighting, control and control circuits. The insulation of conductive conductors, electrically conductive screens and the sheath of a flexible cable according to the prototype can be made of rubber or thermoplastic elastomers (TEP). A flexible cable according to the prototype for a voltage of 6 kV using TEC is manufactured using the following technology. Wires with a diameter of less than 0.5 mm for conductive conductors made of TAS aluminum alloy modified with zirconium are manufactured at a minimum uninterrupted drawing speed using special drawing equipment with very low productivity. The main conductive conductors 1 are twisted on a twisting machine from one or more concentric strands of strands (twisted bundles of wires) in a spiral in alternating directions with a certain twisting pitch. In this case, one strand is placed in the center of the core. The upper strand of strands should have a left torsion direction. The direction of twisting the wires into the strand is left. During twisting TPG can be sealed with crimp rollers. On the main current-carrying conductors 1, screen 2 is successively applied by extrusion from an electrically conductive TEC, insulation 3 from an electrically insulating TEP, screen 4 from an electrically conductive TEP. The insulation thickness depends on the nominal cross-section of the conductive conductors. The inner shield 2 or insulation 3 must be separated from the cores without damage. The core insulation should fit snugly against the screens. Detachment of screens from insulation is not allowed. The auxiliary conductors, the zero core and the grounding core are extruded by insulation from the electrical insulation TEP. It is allowed not to apply insulation to the ground conductor. Insulated conductors are twisted together in a twisting machine. The direction of the strand veins is right. On top of the twisted cores, a separating layer 5 of a polymer film or non-woven fabric is applied. On top of the separation layer, one or two-layer shell 6 of TEC is extruded. In this case, the inner layer of the shell can be made of electrically conductive TEC. The cable cores during cutting should be separated from each other and from the sheath without damaging the insulation and the screen. The disadvantages of the prototype include:

- reduced manufacturability of ultrathin wires made of aluminum alloy modified with zirconium;

- increased cost.

The technical task of the utility model is the development of an electric flexible cable that is not inferior to the prototype in terms of basic characteristics, as well as more technological and more economical, high-quality and highly reliable, designed for non-stationary laying in any conditions. The technical result is achieved in that the conductive wires are made of aluminum wires or alloys thereof, modified with additives from the group of: iron, nickel, titanium, vanadium, chromium, manganese, magnesium, copper, zinc, boron, or mixtures thereof, including wires ductile aluminum alloys with a mesopolycrystalline structure and a grain size of not more than 150 microns. The grain structure of aluminum and its alloys can have a micro, meso and macro level. The microlevel includes an ultrafine-grained structure (UFG) with a grain size of less than 10 microns and a nanocrystalline structure with a grain size of less than 100 nm. A polycrystalline structure with a grain size of not more than 150 μm belongs to the mesoscale. The macro level includes a polycrystalline structure with a grain size of more than 150 microns. The grain size of aluminum and its known alloys for electrical purposes is 500-4000 microns. Aluminum alloys with a mesopolycrystalline structure have increased ductility and resistance to repeated kinks. The mesopolycrystalline structure provides the optimal ratio of strength and ductility of an aluminum alloy necessary for drawing ultra-thin wires with a diameter of less than 0.5 mm

A common feature of the prototype and the proposed technical solution is the presence of insulated multi-wire conductive cores of 5-6 class of flexibility from ultrafine aluminum wires or its alloys with modifying additives having a fine-grained structure. At the same time, the proposed cable differs from the known one using conductive wires made of aluminum wires or its alloys, modified with additives from the group: iron, nickel, titanium, vanadium, chromium, manganese, magnesium, copper, zinc, boron, or mixtures thereof, including from wires of ductile aluminum alloys with a mesopolycrystalline structure and a grain size of not more than 150 microns.

Iron has a modifying effect on aluminum alloys. With an increase in the concentration of iron in aluminum alloys, the grain size decreases. Small additives (up to 0.5 wt.%) Of iron can significantly reduce the creep of the aluminum alloy, which leads to weakening, overheating and rapid destruction of electrical contacts. Reducing creep occurs due to the strengthening of the crystal lattice of an aluminum alloy by iron atoms. In addition, iron additives provide increased strength and heat resistance of the aluminum alloy while maintaining good ductility and electrical conductivity by reducing grain size. Aluminum alloy with the addition of iron lends itself well to heat treatment while maintaining high strength in the annealed state. The effect of iron in an aluminum alloy increases in the presence of nickel. Nickel (up to 0.1 wt.%) Is a modifying additive to increase the heat resistance and corrosion resistance of an aluminum alloy for electrical purposes without reducing its main operational characteristics. Nickel inhibits diffusion processes and forms complex doped finely dispersed hardening phases that are resistant to coagulation when heated. Alloys of aluminum with nickel have high ductility and processability in the hot state during deformation. The sum of heavy metals: titanium, chromium, vanadium and manganese (up to 0.04 wt.%) At an optimal ratio between themselves and other elements limits grain growth and inhibits diffusion processes, forming stable complex-alloyed strengthening phases. This increases the corrosion resistance, strength and heat resistance of the aluminum alloy, significantly reduces the tendency to crack formation. Metals magnesium, copper and zinc have the highest solubility in solid aluminum compared to other known elements, which sharply decreases with decreasing temperature. As a result, when cooling alloys with these components, intermetallic phases are released from the solid solution, and when heated, they dissolve. This phase transformation has made it possible to strongly influence the structure and properties of the aluminum alloy through heat treatment. The sum of these metals (up to 0.1 wt.%) With an optimal ratio between themselves and other elements, primarily silicon, increases the manufacturability of the alloy during heat treatment. At the same time, the strength characteristics of the alloy and its electrical conductivity are improved. Semi-metal boron is also a modifying additive for aluminum alloys. The amount of boron (up to 0.01 mass%), especially in the presence of titanium, effectively grinds the grain of aluminum alloy. Boron contributes to the improvement of mechanical properties, ductility and electrical conductivity, uniformity of properties throughout the volume. Boron also helps to neutralize the negative effects of harmful impurities: gallium, hydrogen, etc. By reacting with these impurities, boron forms insoluble compounds, removing them from solid solution. At the same time, the corrosion resistance of the alloy increases and gas (hydrogen) porosity significantly decreases.

A deformable billet-rod designed for further drawing-rolling in order to obtain ultra-thin wire for flexible cables can be manufactured by continuous casting and rolling, followed by heat treatment by recrystallization annealing. After such processing, the aluminum alloy acquires a mesopolycrystalline structure with a grain size of not more than 150 microns. Thanks to this technology, the required level of plastic, strength and electrical properties of the aluminum billet-rod is achieved and the energy and technological costs of its production are reduced. From this billet-wire rod, an ultra-thin wire with a diameter of less than 0.5 mm is obtained for conductive conductors of a flexible cable by uninterrupted drawing at high speed.

Advantages of the new cable:

- high manufacturability and quality;

- increased performance and reliability;

- increased efficiency.

The design and manufacturing technology of a flexible cable according to a utility model are similar to the design and manufacturing technology of a cable according to the prototype.

The new flexible cable has passed comprehensive tests at cable plants in the Russian Federation and network companies with positive results. Production of these cables has been established.

Claims (2)

1. An electric flexible cable containing insulated multi-wire conductive conductors of 5-6 class of flexibility from ultrathin aluminum wires or its alloys with modifying additives having a fine-grained structure, characterized in that the conductive conductors are made of aluminum wires or its alloys modified with additives from the group: iron, nickel titanium, vanadium, chromium, manganese, magnesium, copper, zinc, boron, or mixtures thereof, including from wires of ductile aluminum alloys with a mesopolycrystalline structure and a size of the pH is not more than 150 microns. 2. An electric flexible cable according to claim 1, characterized in that the wire for conductive cores of an aluminum alloy with a mesopolycrystalline structure is obtained from a heat-treated billet-wire rod.

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