RU174518U1 - Steel strand rope with polymer material - Google Patents

Abstract

The invention relates to the field of steel wire ropes intended for use as load-lifting elements of machines and mechanisms. A rope consists of wire strands, a metal core coated with a polymer sheath, internal filling with polymer material and an outer polymer sheath and, according to a utility model, the polymer component of the rope represents one integral structure both in cross-section and along the length of the rope, and the thickness of the polymer shell on the metal core provides the gaps between the strands and is determined by the expression: where Δ is the thickness of the polymer shell on the metal core, mm; 0.4 is a coefficient that provides the optimal ratio of the diameter of the metal-plastic core to the diameter of the rope; d is the diameter of the rope, mm; d is the diameter of the metal core, mm. Features of the rope design allow to increase the adhesive, aggregate, fatigue strength of the rope.

Description

The utility model relates to the field of steel wire ropes intended for use as lifting elements of machines and assemblies.

Known commercially available steel strand ropes with a metal core for various hoisting and transporting machines and mechanisms having a design of 6 × 7 (1 + 6) + 1 × 7 (1 + 6), double twist rope type LK-O GOST 3066, 6 × 19 (1 + 6 + 6/6) + 7 × 7 (1 + 6), double twist rope, type LK-R GOST 14954, 6 × 36 (1 + 7 × 7/7 + 14) + 7 × 7 (1 +6), double lay rope of the type LK-RO GOST 7669.

The disadvantage of such ropes is the high contact stresses that occur at the points of contact of the wires of adjacent strands and at the points of contact of the wires of the strands and the metal core, as a result of which wire breaks appear in these places leading to premature decommissioning of the rope.

Known steel strand rope, consisting of coils of strands and a metal core coated with a polymer sheath ("Rope production", Moscow, publishing house "Metallurgy", 1980. Author VD Korolev, p. 36, Fig. 26 a and b) .

The rope design has a polymer shell on the metal core and is thus protected from contact between the strand wires and the metal core, but the contact of the wires at the points of contact of adjacent strands remains and, therefore, there is a risk of wire breaks in these places and premature failure of the rope. In addition, the point contact of the outer wires of the strands with the block during the operation of the rope on lifting installations creates good conditions for the wear of the wires and the failure of the rope.

Known rope (invention No. 622904 CL Д07В 1/16), containing strands wound on the core, made in the form of a central strand surrounded by a polymer coating, characterized in that in order to improve the quality of the lubricant on the surface of the polymer coating adjacent to the strands, grooves are made . The presence of lubricant certainly improves the quality of the rope, but the contact of the wires at the points of contact of adjacent strands remains and this is the reason for the reduction of the rope's service life.

Known rope (US patent No. 3874158, 1973), consisting of six strands and a metal core, in which the latter has a plastic coating, and the Central part of the core is lubricated. The presence of a plastic coating on the core and lubrication inside the core can increase the fatigue strength of the rope, however, the mutual contact of the wires of adjacent strands and the point contact of the wires with the block reduces the effectiveness of the application of this invention.

A rope is known that contains a metal core of a cable structure, six strands wound around the core, plastic inserts located between the strands, a polymer coating on the metal core, each plastic insert having a fan-shaped cross section in which there is an enlarged head part, a base part smaller and narrowed part between them, and on the surface of this insert adjacent to the strands are recesses in which the strand wires are placed (US Pat. No. 7,600 366 B2, adopted as a prototype).

The following information can be given for this patent.

The billet used for the production of the insert during the winding of the rope should be 15-30% larger than the gap between the strands. This is determined by the fact that some of the polymer material of the insert is spent on filling the gaps between the wires, and the larger the filling (more than 50%), the more efficient this rope will work. This is due to the larger contact area of the plastic insert with the wire strands, which means that all components of the rope and the rope as a whole will work more aggregately.

The notes on this rope are as follows.

The contact of the strand wires with a plastic insert by filling the gaps between the strand wires by 50%, this space will not provide reliable adhesion of the insert to the strands and does not create reliable conditions for their joint work in industrial conditions. It is more than 50% difficult to get plastic filling the gaps between the wires of the strand, since the polymer material flows into the gaps between the wires in the cold state and it is necessary to actuate large radial forces to compress the rope, and this can cause damage to the rope machine. Insufficient adhesion (adhesion) of the polymer material to the surface of the wire strand does not provide the necessary protection of the rope from corrosion.

In addition, it is very difficult to correlate the size of the gaps between the strand wires and the gaps between the strands with the original size of the workpiece used when twisting the rope to produce the insert, because this is affected by the deviation of the sizes of the wires, strands, the specific gravity of the polymer material, the size of the gap between the strands , and this leads to a possible overflow of gaps with polymer material or their incomplete filling, i.e. to the production of low-quality rope.

The technical result of the claimed utility model is to increase the adhesive strength of the polymer material to the surface of the wires, increase the tensile strength of the polymer component and the rope as a whole, increase the reliability of the protection of the rope from aggressive media and, as a result, increase the reliability of the rope.

The technical result is achieved by the fact that in a steel strand rope with a polymeric material containing twisted strands with gaps between the strands, a metal core of one or more strands of a cable structure, a polymer shell on a metal core of a helical shape, an inner core made of a polymer material, an outer polymer shell, according to a utility model, the polymer shell of the core, the inner polymer filling between the strands and the outer polymer shell form one integral structure yu both over the cross section and length of the rope, the polymer shell thickness on the metal core ensures the gaps between the strands and is defined by the relation:

,

,

 where Δ is the thickness of the polymer shell on the metal core, mm;

0.4 - coefficient providing the optimum ratio of the diameter of the metal-plastic core to the diameter of the rope;

d _to - the diameter of the rope, mm;

d _met. - diameter of the metal core, mm.

The essence of the utility model is illustrated by figures 1 and 2, which depict the construction of the rope and the construction of the polymer component, consisting of a core shell, internal filling, outer shell.

The figure 1 shows the construction of the rope, consisting of six strands having a structure of the type LK-0 (1 + 6 + 12) - 1, the metal core of the cable structure 7 × 7 (1 + 6) - 2, the polymer material - 3, filling the outer and the inside of the rope.

The figure 2 presents the design of the polymer component, consisting of a sheath on the core - 4, internal filling between the strands - 5 and the outer sheath on the rope - 6.

Design features of the rope are as follows.

When applying a polymer material, identical in chemical composition to the polymer shell of the core, onto the rope on the extruder, the polymer flows into the gaps between the strands and wires, the metal core is reunited with the polymer and a single integral structure of the polymer component is formed over the entire cross section of the rope.

The creation of a single integral structure of the polymer component along the entire length and cross-section of the rope due to the use of one polymer material in the molten state will provide a sharp increase in the compatibility of the polymer material and the wires throughout the life of the rope, its breaking strength and, thus, guarantees high rope performance.

In addition, increasing the adhesive strength of the polymer material to the surface of the wires allows to increase the corrosion resistance of the rope in an industrial environment by increasing the difficulty of liquid penetration under the polymer coating.

Establishing the optimal gap between the strands at the level of 0.8-0.9 from the dense laying of the strands in the midwig due to the polymer sheath thickness calculated using the formula ensures the rational construction of the rope, creates improved conditions for the wires in the rope and does not sharply reduce the tensile strength rope as a whole and this allows you to get high performance rope.

LLC SPC Galva conducted a series of tests of the effect of the thickness of the polymer shell on the metal core on the endurance of the rope and established the relationship shown in FIG. 3.

The graph shows the dependence of the thickness of the polymer shell on the metal core with a constant diameter, expressed in terms of the size of the metal-plastic core on the relative endurance of the rope. The test results reveal a large effect of the diameter of the metal-plastic core on the endurance of the rope. Moreover, with a zero thickness of the polymer shell, the endurance of the rope is taken as a unit.

The endurance of the ropes increases with an increase in the ratio of d _mps / d _can. , but to increase this ratio above 0.4 is not rational, since its further increase does not increase the endurance of the rope.

Thus, the expression d _MPS / d _k = 0.4 can be considered the optimal value.

We carry out some transformations.

General characteristics of the claimed utility model with the prototype is:

- the presence of strands in the amount of six pieces, a metal core;

- the presence of a polymer shell on the core, internal filling with polymer material, the outer polymer shell;

- the presence of gaps between the strands;

- the presence of grooves on the polymeric material in which the wire strands are placed.

The difference between the characteristics of the claimed utility model with the prototype is as follows:

- the gap between the strands in the prototype is not controlled, in the claimed utility model it is controlled by the thickness of the polymer shell on the metal core;

- in the prototype, the polymer shell on the rope and the inner filling between the strands exist independently from the polymer shell on the core, in the claimed utility model, the polymer shell and the polymer shell on the core are reunited together and exist together, aggregate, together;

- in the prototype, the thickness of the polymer shell on the metal core is not controlled, in the claimed utility model, the thickness of the polymer shell on the metal core is controlled and determined by the expression:

,

,

which allows you to set the thickness of the shell on the metal core of optimal size.

These differences provide positive qualities of the claimed utility model, namely:

- establishing the optimal gap between the strands through the use of increased thickness of the polymer shell on the core and using the presented formula for calculating the shell thickness allows you to create a rational rope design that gives high performance, where contact of the wires is eliminated at the points of contact of adjacent strands, the formation of dangling wires is excluded and In this way, favorable conditions are created for the continuous operation of the rope in production.

In the prototype, the thickness of the polymer shell on the metal core is not controlled, it is chosen randomly, without a scientific approach to its calculation, and therefore the design recommended by the prototype cannot always provide a gap between the strands and give positive qualities.

In the claimed utility model, the polymer material is used in the hot state and the chemical composition is the same as the chemical composition of the polymer material on the metal core, and therefore favorable conditions are created for filling all the gaps between the strands and wires and connecting the metal core to the polymer, this leads to the creation of a single integral the construction of the polymer component both along the cross-section of the rope and along its length.

The integrity of the construction of the polymer component allows you to maintain high adhesive strength of the polymer material to the surface of the wires, to provide increased aggregate strength of the polymer component and the rope as a whole, to maintain corrosion resistance in industrial conditions at the proper level.

In the prototype, the polymer material used for the production of inserts is used in a cold state, and this does not create conditions for chemical bonding with the polymer material of the metal core and therefore each part of the polymer component works independently, independently and does not always give positive results. In addition, the use of cold material for inserts during the production of the rope does not contribute to the complete filling of the gaps between the wires and thus leads to a decrease in the adhesion strength of the polymer material to the surface of the wires, corrosion resistance of the wires and a decrease in the life of the rope as a whole.

The use of the polymer material in the hot state to fill the gaps between the strands and wires, the formation of a single integral structure of the polymer component over the cross section of the rope, the use of the optimal thickness of the polymer shell on the metal core using the presented formula, which provides rational gaps between the strands, allows you to connect (glue) the wires between yourself and with polymeric material, to get a single aggregated rope, working as a monolithic rod, significantly increasing the efficiency of his work in an industrial environment.

The utility model is implemented on a prototype rope with the following indicators:

- the design of the metal part of the rope 6 × 7 (1 + 6) + 1 × 7 (1 + 6);

- rope diameter - 15 mm;

- the rope has a polymer shell on the core, an inner polymer filling between the strands, an outer polymer coating;

- low pressure polyethylene is used as a polymeric material.

Endurance tests of the rope on a running machine showed positive qualities: the increase in rope endurance was 20% compared with a rope in which the thickness of the polymer shell was smaller.

Claims (6)

Steel strand rope with polymeric material, containing twisted strands with gaps between strands, a metal core of one strand or several strands of a cable structure, a polymer shell on a metal core of a screw-like shape, an inner core made of a polymeric material, an outer polymer shell, characterized in that the polymer shell core, the inner polymer filling between the strands and the outer polymer sheath form a single integral structure both along the cross-section and along the length of the rope, with cm thickness of the polymeric coating on the metal core ensures the gaps between the strands and is defined by the relation:

, where Δ is the thickness of the polymer shell on the metal core, mm; 0.4 - coefficient providing the optimum ratio of the diameter of the metal-plastic core to the diameter of the rope; d _to - the diameter of the rope, mm; d _met. - diameter of the metal core, mm.

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