JP3305844B2 - Manufacturing method of metal cord for rubber composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a metal cord for rubber composites, and more particularly to a rubber composite having excellent corrosion resistance and fatigue resistance used for reinforcing rubber products such as pneumatic tires and industrial belts. The present invention relates to a method for manufacturing a metal cord for use.

[0002]

2. Description of the Related Art In rubber products such as pneumatic tires and industrial belts, a steel cord obtained by twisting a plurality of metal filaments as strands is widely used as a reinforcing material. However, in such a steel cord, if the number of strands is increased, the twisting process becomes complicated and the cost increases. In addition, although the number of wires can be reduced by using a high-strength material for the wires, there is a problem that rigidity is increased and bending stress is reduced. In order to solve this problem, Japanese Patent Application Laid-Open No. 4-304319 describes a metal filament having a specific tensile strength, a shaping ratio of 130% or more, and two-dimensional irregularities. Further, as a manufacturing method, a two-dimensional unevenness is formed by a spur gear rotating by a driving mechanism while applying a predetermined back tension by a brake mechanism for unwinding the filament, and the winding is performed by a motor driven winding machine. Has been described. However, when the metal filament is molded with a gear such as a crimp tooth having a curvature of 400 described in the examples of the publication, the filament damages the gear, and the molded metal filament A two-layer stranded cord or a sheath made by winding another metal filament around the core
When a three-layered twisted cord is produced by winding a metal filament around the layered twisted cord, the unevenness applied to the core filament breaks unevenly in the longitudinal direction. In each case, the tensile strength and fatigue resistance of the cord However, there have been problems such as a decrease in the adhesiveness, and a decrease in the adhesiveness to the rubber due to the peeling off of the film for improving the adhesiveness to the rubber applied to the steel cord.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a rubber composite metal cord having excellent adhesion to rubber, corrosion resistance, and fatigue resistance. It is to provide a manufacturing method of.

[0004]

The method for producing a metal cord for rubber composite according to the present invention is directed to a method for producing a layer-twisted metal cord having at least one core filament obtained by subjecting a metal filament to a corrugation process. Applying oil to the filament; and
A step of applying a flat corrugation with a pair of spur gears while applying a tension of 0.5 to 4.5 kg / piece, and a step of layer-twisting using a metal filament subjected to the plane corrugation as a core filament, The cross-sectional shape of the teeth of the spur gear is a curve, and the tip cylindrical diameter is A, and the root cylindrical diameter is B
When 25 mm ≦ A ≦ 45 mm and the number of teeth is 25 or more, 0.85 A ≦ B ≦ 0.95 A, and when the number of teeth is less than 25, 0.75 A ≦ B < 0.
85A.

[0005]

According to the manufacturing method of the present invention, oil is applied to a metal filament, and while applying tension, the cross-sectional shape of a tooth is a curve, and the diameter of the tooth tip cylinder is A and the diameter of the tooth bottom cylinder is B. When 25 mm ≦ A ≦ 45 mm and the number of teeth is 2
In the case of five or more, 0.85A ≦ B ≦ 0.95A,
When the number of teeth is less than 25, 0.75A ≦ B <0.85A
In order to perform plane waveform processing with a pair of spur gears,
The rotation of the gears is smooth, and the tooth of each gear
Gears mesh because the cross section is a smooth curve
It can be done smoothly. For this reason, the metal filament is not scratched, and the adhesion improver with the rubber covering the filament does not peel off, and is uniform and smooth.
A moderately large waveform is formed. Furthermore, in order to perform layer twist using the filament that has been subjected to this corrugated processing as a core,
The resulting metal cord is excellent in fatigue resistance because unevenness and disconnection of the strand in the twisting step can be prevented.

[0006]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

FIG. 1 is a schematic structural view showing one embodiment of an apparatus used in the method for producing a metal cord for rubber composite of the present invention. 0.34mm diameter forming the core of steel cord
Steel filament F is previously subjected to brass plating in order to improve the adhesion to rubber, and the supply bobbin 10
Wrapped around. A steel filament F drawn from the supply bobbin 10 by the stress of a capstan (not shown) provided in the twisting machine 18 is a constant tension device for adjusting the tension of the steel filament F by controlling the rotation of the roller. After passing through 12, the tension is adjusted to 1.0 kg / piece, and after the lubricating oil (TN-50 manufactured by Nippon Sun Oil Co., Ltd.) is applied by the oil applying device 14 for applying the lubricating oil, the waveform processing is performed. Attached. The tension at this time is preferably 0.5 to 4.5 kg / piece.

FIG. 2A is a cross-sectional view of a spur gear used for corrugating, and FIG. 2B is a vertical cross-sectional view. As is apparent from the cross-sectional view of the spur gear, the tooth profile section is constituted only by a curve. The number of teeth is 20, the tip cylindrical diameter (A) is 33 mm, and the root cylindrical diameter (B) is 26.5 mm.
And the root cylinder diameter is 0.80 times the tooth tip cylinder diameter (B
= 0.80 A). Both the addendum and the dedendum of the spur gear have a smooth curve with a radius (R) of 1, and the addendum curve and the dedendum curve have substantially the same shape with respect to the reference pitch circle. .

The pair of spur gears are engaged with each other,
The rotating shaft is fixed rotatably to form a corrugated molding device 16, and the steel filament F rotates according to the movement of the filament when the pair of spur gears moves, and a planar waveform of a predetermined shape is formed. Formed on steel filament F.

Using one of the corrugated filaments as a core, six corrugated steel filaments having a diameter of 0.34 mm drawn from a sheath filament supply bobbin disposed in the stranded wire machine 18 are used to form a corrugated core. A 1 + 6 steel cord was wound around the filament F.

In the method for producing a steel cord, the steel cord was produced under the same conditions except that the tension of the filament and the tooth profile of the spur gear were changed. Further, a steel cord was manufactured by a different method only in that no lubricating oil was applied. About the obtained steel cord, the rubber penetration ratio, the fatigue resistance index, the rubber sticking index of the core, and the presence or absence of core filament breakage were evaluated. The production conditions and the obtained steel cord performance evaluation results are shown in Tables 1 to 3 below. (Performance evaluation) (1) Rubber penetration ratio 1 + 6 × 0.34 Structural code , that is, corrugated
One core filament and 0.34 mm diameter sheath
A plurality of steel cords formed from six filaments were laid parallel to each other at equal intervals in an unvulcanized rubber sheet, and then vulcanized under heat and pressure. Next, the steel cord was taken out from the vulcanized rubber sheet and cut at 1 mm intervals.
The degree of penetration of the rubber in the section of No. 00 was investigated. 10
100 when rubber intrusion was recognized in all of the 0 cross sections
%, And when no penetration was recognized, the evaluation was made as 0%. (2) Fatigue resistance index The vulcanized rubber sheet was repeatedly bent until the vulcanized rubber sheet was broken by a repeated bending fatigue tester according to JIS L1017 equipped with a roller having a radius of curvature of 15 mm until the vulcanized rubber sheet was broken. The number of times of bending was measured. The evaluation was performed by using an index, with the value of Example 1 being 100. The larger the value, the higher the fatigue resistance. (3) Rubber index of core The steel cord was taken out from the vulcanized rubber sheet, and
The sheath filament is untwisted and a 10 mm core filament is taken out as a sample. The sample was photographed at a magnification of 20 times, and the amount of rubber adhered to the core filament was examined from the photograph. The state where the filament surface is surrounded by rubber is defined as 100. The state where the rubber was not bonded and the filament was exposed was evaluated as 0. (4) Core Filament Disconnection In the case where a steel cord was manufactured continuously for 100,000 meters, the presence or absence of disconnection in the core filament twisting step was inspected.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

As apparent from Tables 1 to 3, the steel cords obtained by the production method under the preferred conditions of the present invention (Examples 1 to 4) have good adhesion to rubber and fatigue resistance, and No breakage of the filament was observed. Furthermore, even if the conditions such as the shape of the spur gear (Examples 5 to 10), the filament tension (Examples 5, 6, 9, and 10), and the diameter of the metal filament (Examples 9 and 10) are changed, the manufacturing method of the present invention can be used. It was confirmed that the steel cords obtained by the above (Examples 5 to 10) had the above-mentioned excellent performance.

On the other hand, a steel cord made of a filament that has been corrugated with a conventional acute spur gear (Comparative 1,
In the case of 2), the rubber penetration ratio and the fatigue resistance were poor, and disconnection of the core filament was also confirmed. In addition, even if the cross section of the teeth of the spur gear is curved, a steel cord (comparative 3, 4, 6, 7) made of a filament obtained by corrugating with a spur gear that does not satisfy the conditions of the present invention is particularly suitable. In the samples having poor fatigue resistance and a sufficient wave-shaped wave height (Comparative Examples 3, 4, and 7), disconnection of the filament was confirmed. Also, the tip cylindrical diameter is 20
In mm, a spur gear having an A: B ratio satisfying the conditions of the present invention could not be produced (Comparative 5), and corrugating could not be performed.

In this embodiment, a lubricant is used as the oil to be applied. However, the type of the oil is not particularly limited, and any oil can be used as long as it reduces friction between the metal filament and the spur gear. However, it is preferable to use an oil used as a rubber softener, since the compatibility with the rubber is good and the penetration of the rubber can be avoided without inhibiting the adhesion to the rubber.

When the spur gear has a curved tooth profile, and the diameter of the tip cylinder of the spur gear is A and the diameter of the bottom cylinder is B,
When 25 mm ≦ A ≦ 45 mm and the number of teeth is 25 or more, 0.85 A ≦ B ≦ 0.95 A, and when the number of teeth is less than 25, 0.75 A ≦ B <0.85 A. If the diameter of the tooth tip cylinder is less than 25 mm, it is difficult to manufacture a spur gear. If the diameter is more than 45 mm, the rotation resistance due to the weight of the gear increases, the rotation does not become smooth, and a uniform waveform is formed. Is difficult to obtain. Further, when the relationship between the tooth tip cylinder diameter and the root cylinder diameter deviates from the above condition, that is, when B is smaller than A,
The difference between A and B, i.e., the spur gear teeth become larger, the teeth become sharper, and the filament breaks more easily.
When B is larger than A, the tooth thickness becomes small, and it becomes difficult to form an appropriate waveform, which is not preferable.

Further, the tension of the metal filament to be corrugated is preferably about 0.5 to 4.5 kg / line. If the tension of the filament is less than 0.5 kg, the rubber penetration ratio is reduced, and if it exceeds 4.5 kg, the filament is liable to be damaged at the time of corrugating, which is not preferable because there is a risk of deterioration of fatigue resistance and disconnection.

The step of applying the oil may be before or after the step of applying the constant tension, as long as it is before the step of applying the corrugated pattern. Preferably later.

[0021]

According to the method for producing a rubber composite metal cord of the present invention, an excellent effect that a rubber composite metal cord excellent in adhesion to rubber, corrosion resistance, and fatigue resistance can be obtained. Indicated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of an apparatus used for a method of manufacturing a rubber composite metal cord according to the present invention.

FIG. 2 shows a transverse sectional view (a) and a longitudinal sectional view (b) of one spur gear used in the manufacturing method of the present invention.

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Claims (1)

(57) [Claims] 1. A method for producing a layer twisted metal cord comprising at least one core filament has been subjected to a plane wave processed into metal filament, a step of applying the oil to the metal filament, the metal filament, 0.5 A step of applying a flat corrugation with a pair of spur gears while applying a tension of about 4.5 kg / piece, and a step of performing a layer twist using the metal filament subjected to the flat corrugation as a core filament. When the cross-sectional shape of the teeth of the spur gear is a curve, and the tip cylinder diameter is A and the root cylinder diameter is B, 25 mm ≦ A ≦
When the length is 45 mm and the number of teeth is 25 or more, 0.
85A ≦ B ≦ 0.95A, and 0.75A ≦ B <0.85A when the number of teeth is less than 25. A method for producing a metal cord for rubber composite, comprising: