JP2620414B2 - Twisted twisted wire machine for steel cord production - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a reinforcing fiber for a rubber structure such as an automobile tire or a conveyor belt.

[0002] More specifically, the present invention relates to a double twist twisting machine used for manufacturing a steel tire cord for reinforcing a radial tire.

[0003]

2. Description of the Related Art In recent years, due to the development of expressways and the accompanying increase in transportation efficiency, the tendency to increase the traveling speed has been gradually increasing. Along with this, there is an increasing demand for improvement in tire weight reduction not only for high-speed durability of the tire but also for low fuel consumption and environmental conservation.

[0004] In particular, tires reinforced with steel cords are currently heavy due to the high specific gravity of the steel cords. As a countermeasure, the carbon content among the chemical components of the steel filament forming the steel cord is particularly increased from 0.67 to 0.75% by weight to 0.7.
The tensile strength of the steel filament is improved by increasing it to 8 to 0.85% by weight or by increasing the cumulative area reduction rate in the final finishing wire drawing step. Further, since the tensile strength of the steel cord obtained by twisting them is also improved, the diameter of the filament can be reduced by the increased tensile strength. Even if the number of steel cords to be driven is the same, the tire can be reduced in weight.

[0005] However, the improvement in the tensile strength of the steel filaments on the side of the steel cord manufacturing side causes severe twisting of the steel filaments, particularly in the case of a two-ply twisting machine in which the twisting process is highly productive. For this reason, the current situation is that the disconnection rate is 3 to 5 times that of the conventional steel filament.

[0006] Further, it has been desired to reduce breakage during twisting even in a conventional steel filament.

FIG. 2 shows a conventional double twist twisting machine. In this drawing, reference numeral 1 denotes a steel filament drawn from a plurality of supply bobbins (not shown);
Are steel strand cores, each of which passes through the eyelet die 3, is twisted twice through the twisting die 4 through the front and rear guide rollers 5 and the front and rear flyers 6, and is elastically limited by an over twister or false twist device 7. After adding and untwisting a twist corresponding to the twist of the upper and lower capstan rollers 8, the upper and lower traverse rollers 1
It is guided to 0 and wound on the take-up reel 11. While reciprocating between the rollers 8, a plurality of small-diameter rollers are straightened through a straightening device 9 arranged in a staggered manner to remove twist. In the case of the drawing, the false twist device 7 is installed after the double twist, but may be provided before the double twist.

[0008]

In this type of twisting machine, a twist is added to the steel filament as much as the number of twists. This torsion is almost completely eliminated by plastic deformation in a low elasticity material such as copper and aluminum, so that it is not necessary to remove the torsion by additional processing after twisting. However, in the case of steel wire, which is a high elastic modulus material, since the twist corresponding to the elastic limit remains, as additional processing, a twist equivalent to the twist of the elastic limit is added by a false twisting device provided before or after twisting. Later, twisting is performed by untwisting.

As described above, the twist required to obtain a predetermined twist pitch is added to the steel filament, and further the temporary twist is added by the number of times of twisting by the false twist device. Has the disadvantage that the number of times of twisting of the steel filament is maximized and the steel filament is easily broken. The object of the present invention is to reduce the disconnection rate of the twisting step by controlling the number of twists of the steel filament to a minimum, using a double twist twisting machine,
Furthermore, the reduction rate of the tensile strength of the steel filament due to the twisting can be minimized.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a steel cord having a single twist structure comprising two to five steel filaments having a tensile strength of 250 kgf / mm ² or more, or A twin-twisting wire machine used for producing a steel cord having a double-layered twisted structure constituted by twisting the above steel filaments on a steel strand core consisting of two to four steel filaments. Steel filament or steel strand core and steel plate core to be combined, steel plate die for passing steel filament, steel filament after steel plate die, twisted die for assembling steel strand core, front flyer and rear flyer each with a guide roller, front and rear flyers Pairs of capstanloes installed on board the aircraft A straightener, a straightener, a traverse roller and a take-up reel.The twisted cord is guided from the twisting die to the front guide roller, the front flyer, the rear flyer, and the rear guide roller in order, and the twisted cord passes through the center hole of the rear flyer to be installed in the machine. After being guided by one capstan roller and reciprocating between the pair of capstan rollers, the other capstan roller is configured to reach a take-up reel via a traverse roller, and further, the straightener includes a plurality of small-diameter rollers. The straighteners are arranged in a zigzag pattern.The straighteners are installed on the outward and return paths of the cord between the pair of capstans, and the twists remaining on the steel filament are removed by the multiple straighteners to ensure the straightness of the cord. The present invention provides a twin-twisting machine for producing a steel cord.

[0011]

In the conventional twisting device, the removal of the residual twist is performed by a roller type straightener, and the false twist device for once applying an excessive twist to the steel filament is eliminated. In addition, breakage of the filament due to excessive twisting is prevented, and a decrease in the tensile strength of the filament is also suppressed.

[0012]

FIG. 1 shows an embodiment of the present invention.
Most of this embodiment is the same as the conventional example of FIG.
The same reference numerals are given and the description is omitted. As is clear from this figure, the false twist device 7 shown in FIG. 2 is abolished, and a straightener 9 is added instead. Therefore, this embodiment is different from the conventional example shown in FIG. 2 in that there is no false twisting device (overtwister), and instead two sets of straightening devices 9 having small-diameter rollers arranged in a staggered manner are provided. However, the corrector 9
May be three or more sets.

In the above-described embodiment, the twist is removed and the straightness of the cord is ensured only by the straightening device 9 in the double-twisting wire machine, and the other operations are the same as those of the conventional method. Thus, in this embodiment, since there is no false twisting device, the twisting pitch does not exceed the final twisting pitch in the twisting process.

The twist removal during the twisting process by the above-described embodiment and the conventional twisted wire manufacturing apparatus shown in FIG. 2 will be described with reference to FIGS. 3, 4 and 5 showing the number of twists-torsion torque curves.

FIGS. 4 and 5 show the relationship between the number of twists given to the cord and the torsion torque when the twisting is performed by the conventional method shown in FIG. 2, and FIG. 4 shows the embodiment of FIG. FIG. 5 is a diagram showing a case where there is a false twist device after twisting, and FIG. 5 is a diagram showing a case where there is a false twist device before twisting.

In each of the above-described diagrams of FIGS.
The trajectory started from the point where q is the final reaching point, and this point indicates the final twist pitch (or the number of twists). Each of the diagrams in FIGS. While passing through the point s, the diagram of FIG. 3 according to the embodiment of the present invention passes through the same number of twists p ′ as the point q. By reducing the number of twists, that is, the number of twists, applied to each filament constituting the cord as much as possible, the disconnection rate in the twisting step can be significantly reduced, and the rate of decrease in the tensile strength of the filament due to the twisting process is minimized. Can be kept to a minimum.

Next, specific data of the embodiment will be shown.

First, a brass-plated steel filament and a steel strand core for a steel cord shown in Tables 1 and 2 are prepared, and a cord having a two-layer twist structure of 3 × 0.20 + 6 × 0.35 is shown in FIGS. 1 and 2. The disconnection rate when manufactured by the twisting method and the tensile strength of the obtained steel cord were examined.

Table 3 shows the results.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

As described above, the twisting machine of the present invention eliminates the conventionally used false twisting device, and removes the twist that relies on the false twisting device by using an additional roller type straightener. since, for the steel filaments with a tensile strength of 250 kgf / mm ² or more, twisting as stranding the return does not occur in an efficient twice twisted manner without adding excessive twist will cause breakage and tensile strength reduction It can contribute to high quality of steel cord and drastic reduction of stranded wire cost.

The steel cord produced by the twisting machine of the present invention is particularly suitable for use as a reinforcing fiber for a rubber structure such as a vehicle tire or a conveyor belt.

[Brief description of the drawings]

FIG. 1 is a front view of an embodiment.

FIG. 2 is a front view of a conventional example.

FIG. 3 is a graph showing the number of twists versus torsion torque of a cord manufactured according to an example.

FIG. 4 is a graph showing the number of twists—torsion torque curve of a cord manufactured according to a conventional example.

FIG. 5 shows the number of twists of a cord manufactured according to another conventional example.
Torsion torque curve diagram

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 steel filament 2 steel strand core 3 face die 4 twisting die 5 guide roller 6 flyer 7 false twisting device 8 capstan roller 9 straightener 10 traverse roller 11 take-up reel A rotation number of double twist twisting machine B Rotation speed of twisting device B 'Rotation speed of back false twisting device C Rotation speed of front false twisting device

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-87940 (JP, A) JP-A-58-23525 (JP, A) JP-A-58-23527 (JP, A) 8904 (JP, Y2)

Claims (1)

(57) [Claims] 1. A steel cord having a single twist structure composed of 2 to 5 steel filaments having a tensile strength of 250 kgf / mm ² or more, or a steel strand core composed of 2 to 4 steel filaments as described above. A double-twisting wire machine used for manufacturing a steel cord having a two-layer twist structure constituted by twisting the steel filaments, and a steel plate die or a steel plate core through which a steel filament or a steel strand core is twisted with each other, Steel filament after passing through the face plate dies, twisted dies for collecting steel strand cores, front and rear flyers each with a guide roller, a pair of capstan rollers, straighteners, and traverses installed in the machine between the front and rear flyers Roller and take-up reel, twisted From the die, the front guide roller, the front flyer, the rear flyer, and the rear guide roller are sequentially guided, and the twisted cord is guided to one of the capstan rollers in the machine through the center hole of the rear flyer, and between the pair of capstan rollers. After reciprocating, the other capstan roller reaches the take-up reel via the traverse roller,
Further, the straightening device is configured by arranging a plurality of small-diameter rollers in a staggered manner, and the straightening device is installed on each of the forward and backward paths of the cord between the pair of capstan rollers. Twisting and twisting machine for steel cord production that removes twists remaining in the steel filament and ensures straightness of the cord.