JPS6059188A - Steel cord for reinforcing rubber article - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Technical Field) Steel cords are generally used to strengthen rubber articles by being embedded inside molded articles of rubber or rubber-like elastic materials, such as pneumatic rubber tires and conveyor belts. The technical content described in this specification regarding improvement is the development result aimed mainly at improving the strength and efficiency of the steel cord for reinforcing rubber articles, as well as the fatigue resistance, and is a composite material mainly made of rubber or rubber-like elastic material. It is located in the field of technology related to.

(Background Art) Regarding this type of reinforcing steel cord, there is a steel cord having a structure in which all of its filaments are twisted in the same direction and at the same twist pitch.1. .

So-called compact cords have been attracting attention recently.

This is because, in the above twisted structure, the filaments are in complete line contact with each other, and the so-called 7-letting wear disadvantage resulting from the point contact of the filaments in conventional steel cords can be avoided. However, conventionally, so-called puncher-type twisting machines have been used to twist this type of steel cord, mainly from the viewpoint of productivity, and the twisting mechanism involves twisting the filaments. .

(Problem) The inventors are making efforts to elucidate the performance of this type of cord as a composite with rubber through the development and test production. It was discovered that it has some drawbacks.

One is related to fatigue resistance, and the other is related to adhesion stability.
Regarding the order of these intervals, among the rubber composite molded products,
The discovery was made during actual performance tests of steel radial pneumatic rubber tires for trucks and buses, which are used under particularly severe load conditions.

In other words, the so-called composite function is lost in the form of tire burst due to cord fatigue failure of the belt or ply caused by the steel cord, and separation due to decreased adhesion between the rubber and the cord. It is clear that it occurs not only in conveyor belts, high-pressure hoses, ponds, reinforced with steel cords, but also in reinforced rubber and articles.

On the other hand, from the viewpoint of producing steel cords such as those mentioned above, although it has been said that the lifting puncher type twisting machine has high productivity in one process of twisting, when it is used in the actual process, it often fails. The decrease in operating rate due to filament breakage was more severe than expected, and even productivity was affected.
It became clear that there were still problems.

(The beginning of the idea) As a result of trying to clarify the causes of these problems, we found that all of them essentially have a common phenomenon, that is, the steel cord twisted by a puncher type twisting machine has a phenomenon that each filament It has become clear that this is due to the introduction of an unavoidable torsional component.

In other words, the decrease in fatigue resistance is due to a decrease in the toughness of the filament itself due to the addition of a twisting component to the filament, which promotes fatigue fracture under repeated bending deformation under load conditions of rubber articles, especially rubber tires. The instability is caused by the torsional stress υIIJ on the filament, which causes the positive plating layer on the surface and the iron base to 1! In addition to the decrease in the plating bonding strength of l, due to the decrease in the physical properties of the plating layer σ), the bonding strength between the rubber and σ)
σ) The effect of improving adhesion is also reduced, and the bond is broken early under the conditions of use of rubber tires.

Furthermore, a decrease in productivity due to filament breakage during the production process is also caused by the twist introduced into the filament. It is an object of the present invention to solve the above problems and to propose a steel cord for reinforcing hanging rubber parts, which improves the fatigue resistance of the steel cord, stabilizes its adhesion, and improves productivity. (Structure) The above objectives are fulfilled by a system based on the following points.

, a steel cord in which multiple steel filaments are twisted together in the same twist direction and at the same twist pitch, each filament being equal to the number of filaments required for each layer of the multi-layer twisted steel cord including fur. A steel cord for reinforcing rubber articles, which is formed into a twisted structure with virtually no torsional components by spiral twisting using a preformer combined with a tubular twisting machine that accommodates a corresponding filament bobbin.

Here, the tubular twisting machine is combined with this.

When the filament is helicalized using the pre-7 ohmer wire, only plastic bending is performed and virtually no torsional deformation is applied, so there is no deterioration in the toughness of the filament itself, which contributes to the fatigue durability of the cord. Further, since the physical properties of the positive plating layer on the surface of the filament do not deteriorate due to torsional deformation, the adhesion to rubber by the plating layer is not impaired.

Furthermore, there is less risk of filament breakage during the twisting process, which helps improve productivity, especially since all filaments, including the core, are twisted in one process for multilayer twisted cords.

This, combined with the reduction in wire breaks, significantly improves productivity.

The cross section of the steel cord for reinforcing rubber articles having the above structure is illustrated in Figures 1(a) to (f). (b) (3 filaments, 9 outer layers, and (0) surrounding the core of the filament, a first outer layer of 9 filaments, a second outer layer of 15 filaments, and (tel) , an outer layer of 10 filaments around 4 furs, (fl is a compact type steel cord having an outer layer of 12 filaments around 6 cores, among which (bl
As a representative example, as shown in FIG. 2 (al) showing the appearance in the case of two twists, each filament is twisted in the same direction and has the same pitch. Of course, S twist may be used in this twist direction.

Figure 2 (bl and (C1) show the presence or absence of twist for one filament of the same figure (al). Conventional compact type steel cords are twisted together using a puncher twisting machine, so Figure 2 (b) ), the twist shown by the dashed line was inevitably introduced, whereas in the present invention, as shown by the two-dot chain line in (0) of the same figure, no twist is actually introduced.

The steel cord for reinforcing rubber articles according to the present invention is the eighth steel cord for reinforcing rubber articles.
The tubular twisting machine 1 shown in the figure is combined with a pre-seven ohmer 2, and twisted together while reaching a take-up spool via a guide roller 4 under tension from a pair of drive pulleys 3.

Here, in the tubular twisting machine, for each filament of the steel cord, the number of filaments corresponding to the number of filaments required for each layer of the cord including the core (6) is pivoted so that the filament bobbin can be fed out from the bobbin. A cradle 7 is a cradle 6 which has a spindle that rotates and is swingably held on the axis of the tubular twisting machine.
filament guide rollers supported by 8, 9,
10 is a filament guide roller supported on a tubular twisting machine, 11 is a guide plate, and 12 is a twisting guide that sandwiches the pre-7 ohmer 2 between the guide plate 11 and the guide plate 11.

As shown in FIG. 5 for one filament bath, the pre-7ohmer 2 has a set of at least three filament bins 18, 14 and 15, respectively, on the end shaft 16 of the tubular twisting machine 1. Colors 17, 18 and 1
By protruding from 9 and holding and fixing each collar so that the circumferential spacing of each pin can be adjusted, the filament 20 drawn out from each filament bobbin is spirally threaded as shown in 20'. The filaments 20' are twisted together as a cord 21 with virtually no torsion component.

This preformer 2 creates an independent spiral pattern for each filament, which increases the degree of processing to match the spiral cedar shape of the filaments in the twisted steel and cord.
00%, it can be freely adjusted within the range of 20 to 200%, particularly preferably 50 to 150%.

Of course, the steel cord 21 obtained by helical twisting of 100% or less becomes the above-mentioned compact type, and by performing helical twisting of more than 1%lO%, various open type steel cords can be obtained without disturbing the filament arrangement. In this case, the penetration of the rubber between the filaments is ensured, and with proper knowledge of adhesion to the rubber, cord corrosion due to water intrusion due to cutting of tires, for example, can be advantageously avoided.

As above, what filament is required for each layer of multilayer stranded steel cord, including the core? , 'A tubular twisting machine 1 containing a number of filament bobbins according to the number of filament bobbins.
The helical deformation applied to the filaments by combining the preformer 2 for helical twisting of each filament and twisting them into the steel k-x-)-21 is essentially a torsional deformation with only the bending component l. Since this method does not introduce any deterioration in the toughness of the filament itself, there is no residual shear stress due to twisting, and the disadvantages of steel cord such as deterioration in strength, efficiency, fatigue resistance, and adhesion with rubber are completely eliminated. Moreover, there is less concern about productivity reduction due to wire breakage during stranded wire processing.

Regarding the steel coat for reinforcing rubber articles according to this invention,
As a fatigue test, a rotating bending fatigue test, a 30-lar tension bending test, and an adhesion test were carried out as follows: 1. .

A peeling test and a peeling test after use of truck and bus tires were conducted and the results shown below were obtained.

In addition, in the rotating bending fatigue test, the bending curvature radius is lυ ~ 20
The number of revolutions at which breakage occurs due to rotation, and the 30-ler test is performed by winding a steel cord with one end fixed around eight rollers with an outer diameter of 40 degrees, and passing the other end through a guide sheep to make the cord stronger. A corresponding weight is hung, and eight rollers are wound between them, and the steel tool F is moved horizontally along the cord with enough strokes to apply bending in both positive and negative directions, and the number of reciprocations required to reach breakage. evaluated.

80-La tension bending test (number of bends) Adhesiveness test Wire breakage rate For the breakage rate in the process of producing 1 ton of product steel cord (I At that time, the breakage rate index of the steel cord of the present invention was 20.

Since then, typical embodiments of this invention have been described,
Similar benefits can be expected even if the number of filaments is 19, 80.87°, 44.48, or 52, and in any case, spiral wrapping may be performed as necessary to produce a product. .

(Effects of the invention) When forming a filament into a helical cord, most of the filament bending component σ is 2, and there is almost no torsion component, so there is little deterioration in the toughness of the filament itself and the fatigue durability of the cord is improved. It is possible to reduce the decrease in the bond strength between the plating and iron base due to shear deformation of the surface of the plating layer due to filament torsion deformation, and to reduce the change in the physical properties of the plating (high adhesion can be guaranteed over the welding period). Since there is no over-twisting to kill the elastic untwisting, as in As a result, even in a multilayer structure, there is a twist seam in the l process.

productivity. The same pitch and twist direction can be easily controlled, and pitch variations in the longitudinal direction can be completely suppressed, reducing fatigue variation and making it easy to control filament curl. All filaments, each layer, one filament per layer, depending on the purpose of use.The spiral attachment of each filament can be freely controlled, making it easy to penetrate the rubber between the filaments of the steel cord. Can be secured.

[Brief explanation of the drawing]

FIGS. 1(a) to (fl are cross-sectional views of cords of different embodiments according to the present invention, FIG. 2(al) is an external view of the one shown in FIG. 1(b), and FIG.
b), (C1 is an explanatory diagram that distinguishes the presence or absence of twist in one filament, Fig. 3 is an explanatory diagram of the procedure for twisting wire by a combination of a tubular twisting machine and a briformer, Fig. 4 (a) , (b) is a detailed view of the main part of the Buriforma, and FIG. 5 is an explanatory diagram of the helical attachment point 1 by the Buriforma.〇Patent applicant Brideston Bekaert Steel 1.
. Code Co., Ltd. Figure 1 < a >< 1) ) @ Ticket tc) < d) + [) (f) Kushi Hata Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] L A steel cord in which multiple steel filaments are twisted in the same twist direction and at the same twist pitch, and each filament is a filament bobbin that corresponds to the number of filaments required for each layer of the multilayer twisted steel cord including the core. A steel cord for reinforcing rubber articles, which has a twisted structure virtually free of twisting components through spiral twisting using a pre-7ohma combined with a tubular twisting machine.