JP3248631B2 - Method and apparatus for manufacturing metal cord - 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 and an apparatus for manufacturing a metal cord used for reinforcing rubber articles such as automobile tires and conveyor belt high pressure hoses.
More particularly, the present invention relates to a method and an apparatus for manufacturing a metal cord having a structure effective for improving the durability of a rubber article.

[0002]

2. Description of the Related Art In general, a metal cord for reinforcing a rubber article is formed by twisting a plurality of metal filaments, and in order to impart adhesiveness to rubber, a brass, copper, zinc or the like is applied to the surface of a material (JISG3502 piano wire, etc.). Metal plating. However, since the plating thickness is usually as thin as about 0.2 μm, if there is a portion that is not covered with rubber in a portion adjacent to the metal filament, moisture in the rubber and damage caused by the rubber reach the metal cord. In such a case, erosion occurs in a short period of time due to the permeated moisture, and the cutting load and fatigue resistance at that location decrease. Further, when used for reinforcing automobile tires, if the adhesiveness between the cord and the rubber is reduced and the rubber is peeled off, there is a possibility that a trouble due to so-called separation of the tire may occur.

[0003] On the other hand, a so-called open cord, which has a poor twist, can relatively reliably cover the entire circumference of each metal filament, but is structurally unstable. Therefore, a technique has been proposed which can compensate for the drawbacks in using the open cord and improve the rubber coverage of each metal filament constituting the metal cord.

[0004] For example, Japanese Patent Publication No. 63-63293 discloses a rotating wave applicator in which a plurality of hammering pins are alternately arranged, and all metal filaments are individually waved at a smaller pitch than the twist pitch. A technique has been disclosed in which these are twisted by a double twisting and twisting machine so as to form a gap between the metal filaments to improve the penetration of rubber.

Japanese Patent Application Laid-Open No. 2-307994 discloses that, among three or more metal filaments constituting a metal cord,
Disclosed is a technique in which a plurality of filaments are passed between opposing gears and corrugated in a zigzag shape, and then twisted with other straight metal filaments, thereby creating a gap between each filament to improve rubber permeability. Have been.

[0006]

When the filament shapes before twisting are the same as in the above technique, the tension before twisting may be the same. However, in the case of twisting a corrugated filament and a straight filament as in the technology described above, if the two strands are twisted with the same pre-twisting tension, if the metal cord is cut, The filaments protrude more than the straight filaments, resulting in uneven terminals, resulting in reduced cord strength and increased low load range elongation (hereinafter referred to as initial elongation). For this reason, there has been a problem that the cords become loose when the cords are aligned when producing the cord / rubber composite, and the cords intersect or the cord intervals become irregular.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a method of manufacturing a metal cord having a good rubber permeability and eliminating terminal irregularities between a corrugated filament and a straight filament. It is to provide the device.

[0008]

In order to achieve the above object, a method of the present invention is to provide a method in which a total of n metal filaments are collectively converged from a plurality of supply reels and then fed out via a dancer roller. Separation and branching, of which a maximum of (n-1) metal filaments are corrugated in advance, and the other metal filaments are straightened, and all metal filaments are twisted twice by a twisting and twisting machine. Wherein the pre-twist opening tension of each metal filament satisfies the following condition. 1.1Ts ≦ Tw ≦ 1.5Ts Tw is the pre-twisting tension of the corrugated metal filament Ts is the pre-twisting tension of the straight metal filament

Here, it is preferable that the pre-twist opening tension of the corrugated metal filament is added before the corrugation. Further, it is preferable to first apply a constant tension to all the metal filaments, and then apply additional tension to the metal filament to be corrugated.

[0010] Further, an apparatus for implementing this manufacturing method comprises a supply reel for supplying a total of n metal filaments, and all the metal filaments supplied from the reel are collectively converged and fed out, and then separated by dancer rollers. , A constant tension applying device for applying a tension by dividing, and a corrugating device for preliminarily corrugating a maximum of (n-1) metal filaments among the divided metal filaments. What is claimed is: 1. A metal cord manufacturing apparatus comprising a double-twisting wire twisting machine for twisting a metal filament subjected to a braiding process and the remaining straight metal filaments which are not corrugated, wherein the constant tension applying device and the corrugating device are provided. And an additional tension applying device for additionally applying tension to the metal filament.

An embodiment of the present invention will be described with reference to the drawings. In this example, for a 1 × 3 single-twisted structure, one metal filament that has been subjected to a spiral corrugation process finer than the twist pitch and two straight metal filaments that have not been corrugated have been twisted together. A case of producing a code will be described as an example.

FIG. 1 is a schematic view showing the apparatus of the present invention, in which a total of n metal filaments F are sent out from a plurality of supply reels 1 and tension is added in advance to a part Fw of the corrugated processing. It is twisted with another straight filament Fs by the double twist twisting machine 8. First, the supply reel 1 will be described. Three metal filaments F are prepared corresponding to the respective metal filaments F. Here, the metal filaments F are roughly adjusted in tension and then collectively converged by the payout capstan 2 to the dancer roller 3. Will be sent out.

The dancer roller 3 constitutes a constant tension applying device for applying a constant tension to each of the metal filaments F to separate and divide the metal filaments F. Here, among the three metal filaments,
One is sent to the additional tension applying device 4 and the other two are sent to the guide roller 6.

The additional tension applying device 4 adds a tension to a metal filament to be corrugated later, and includes a flanged wheel 4a and a brake mechanism 4b. The tension may be added by winding the metal filament sent from the dancer roller several times around the flanged wheel 4a. If the wheel 4a is made rotatable, the wheel 4a will be rotated by the pulling force of the pulling capstan in the twisting machine described later.However, by providing the brake mechanism 4b on the wheel, the force for suppressing the rotation of the wheel 4a is increased. Can occur. Therefore, as a result, the tension at the wheel outlet side becomes larger than that at the inlet side, so that additional tension can be added. The reason why the metal filament is wound several times around the wheel 4a is to reduce the slip between them. The tensioned metal filament is then introduced into the corrugating device 5.

The corrugating device 5 itself forms a spiral-wave permanent deformation by rotating itself and passing a metal filament between corrugated pins alternately arranged therein. The corrugated filament Fw processed here is supplied to the twisting die 7 together with the straight filament Fs sent through the guide roller 6. And it is introduce | transduced into the double twist wire machine 8.

The double twisting and twisting machine 8 comprises a flyer 10 and a cradle 11 which is swingably disposed inside the flyer and has a take-up capstan 12, a take-up reel 13, and the like. Flyer 10 is cradle 1
1 to give twist to the metal filament, and the supplied metal filament is finally taken up by a take-up reel via a first turn roller 9, a flyer 10, a second turn roller 14, and a take-up capstan 12. 13 is wound as a metal cord C. Reference numeral 15 denotes a false twist device.

The metal cord produced by the method of the present invention has a gap between the corrugated filament Fw and the straight filament Fs, as shown in FIG. That is, the corrugated filament Fw draws a spiral in the longitudinal direction while inscribed in the small circle a in the figure, and in this state, is twisted with the other straight filament Fs while inscribed in the great circle A. Therefore, a gap is formed between the adjacent filaments due to the difference in diameter between the small circle a and the metal filament (this is the remaining amount of the corrugated height), and the rubber penetrates into the gaps, so that a reliable coating can be achieved, and Corrosion resistance is maintained.

[0018]

In general, when twisting metal filaments having a single twist structure, a tension corresponding to 10 to 20% of the cutting load of the metal filament is uniformly applied to each filament, although it varies slightly depending on the type of the twisting machine.

By the way, in the conventional twisting of a stretchable corrugated filament and a straight filament that is difficult to stretch, especially in the case of a double twisted wire machine, as shown in FIG.
The twist point exists from the twisting port where twisting starts once (twisting die 7 in FIG. 1) to the vicinity of the second turn roller where double twisting ends. For this reason, tension is applied to each metal filament by contact resistance generated when passing through various guides until twisting is completed. Therefore, the stretchable corrugated filament is stretched during this time, and when the resulting metal cord is cut, a phenomenon occurs in which the corrugated filament protrudes as compared with the straight filament at the end.

When such a metal cord is subjected to a tensile test as described above, the load burden on each filament becomes uneven, the cord strength is reduced, and the initial elongation is increased. It is easy to cause various troubles.

When twisting metal filaments having different elongation characteristics as described above, the present inventors lead the stretchable corrugated filament to the twisting opening with a stronger tension applied than the straight filament, so that the ends of the wire are uneven. I found that the problem could be solved. Thereby, even if tension is applied due to contact resistance with various guides before the subsequent twisting is completed, the elongation due to the tension is reduced. Therefore, when the finished cord is cut, the amount of protrusion of the stretchable corrugated filament can be extremely reduced, and the metal cord without protrusion can be controlled by controlling the amount of pre-twisting opening tension according to the wave shape. Can be manufactured.

The pre-twist opening tension of this corrugated filament needs to be about 1.1 to 1.5 times that of a straight filament. If it is less than 1.1 times, the above-mentioned problem is likely to occur because the tension of the corrugated filament cannot always be increased due to the variation in tension. On the other hand, if it exceeds 1.5 times, in the process of twisting, the corrugated filaments will push the straight filaments. If the total number of filaments n is 4 to 5, the corrugated filaments will be in the center of the cord. It becomes easy to enter and causes uneven twisting. On the other hand, when the number of n is three, the central portion of the three strands is deviated to the corrugated filament side, and becomes an eccentric cord, which is not preferable because the unevenness of the surface is increased.

It is not preferable to provide such a tension applying device after the corrugating device and before the twisting port, since the corrugated shape of the filament formed by the corrugating device tends to disappear.

[0024]

Test Example A metal cord was actually manufactured using the above-described apparatus shown in FIG. 1, and a test was conducted to confirm the effect. The test method was performed by changing the additional tension of the corrugated filament in various ways, and examining the irregularity amount and the initial elongation value at the end of the obtained metal cord. The initial elongation is indicated by the elongation at a tensile load of 0 to 5 kgf by a tensile test. The test conditions are as follows.

Metal cord: 1 × 3 × 0.27 mm single stranded structure One corrugated, two straight filaments Corrugation: Corrugated pitch; 6.2 mm Corrugated height; 0.25 mm Corrugated direction Spiral wave of S Twisting condition: Twist pitch; 12.5 mm Twist direction; S twist Twist speed; 100 m / min

The test results are shown in Table 1. As shown in the table, in each of the comparative examples, the irregular amount of the cord terminal was large, and irregularities were observed on the cord surface. On the other hand, in the metal cord according to the embodiment, the irregular amount of the terminal is 1 m.
m or less, the initial elongation could be suppressed, and it was confirmed that the surface had no irregularities and was of high quality.

[0027]

As described above, according to the present invention,
By guiding the stretchable corrugated filament to the twist opening with a stronger tension applied than the straight filament and twisting, it is possible to minimize irregularities in the terminals. In addition, since the initial elongation can be suppressed and the surface of the cord can be kept free from irregularities, problems such as a decrease in cord strength can be solved, and a metal cord in which rubber easily penetrates into the cord can be provided. . Therefore, durability,
Automotive tires, high-pressure hoses,
It is effective if used for the production of metal cords for reinforcing rubber articles such as conveyor belts.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an outline of a device of the present invention.

FIG. 2 is a cross-sectional view showing a metal cord obtained by the method of the present invention.

[Explanation of symbols]

 Reference Signs List 1 supply reel 2 payout capstan 3 dancer roller 4 additional tension applying device 4a flanged wheel 4b brake mechanism 5 corrugating device 6 guide roller 7 twist opening die 8 double twist twisting machine 9 first turn roller 10 flyer 11 cradle 12 Take-up capstan 13 Take-up reel 14 Second turn roller 15 False twist device F Metal filament Fw Corrugated filament Fs Straight filament C Metal cord a Small circle A Large circle

[Table 1]

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B21F 7/00 D07B 1/06

Claims (4)

(57) [Claims] 1. A total of n metal filaments are collectively converged and fed out from a plurality of supply reels, and then separated and split via a dancer roller.
1) A method of manufacturing a metal cord in which the metal filaments are preliminarily corrugated and the other metal filaments are straightened and all the metal filaments are twisted twice by a twisting and twisting machine. A method for producing a metal cord, wherein the opening tension satisfies the following condition. 1.1Ts ≦ Tw ≦ 1.5Ts Tw is the pre-twisting tension of the corrugated metal filament Ts is the pre-twisting tension of the straight metal filament 2. The method for producing a metal cord according to claim 1, wherein the pre-twist opening tension of the corrugated metal filament is added before the corrugation. 3. The method according to claim 1, wherein a constant tension is first applied to all the metal filaments, and then a further tension is applied to the corrugated metal filament. 4. A supply reel for supplying a total of n metal filaments, and all the metal filaments supplied from the reel are collectively converged and fed out, and then separated and separated by dancer rollers to apply tension. A constant-tension applying device, and a corrugating device for corrugating a maximum of (n-1) metal filaments out of the divided metal filaments, and further comprising a corrugated metal filament; An apparatus for manufacturing a metal cord having a double twisting and twisting machine for twisting the remaining uncorrugated straight metal filaments, wherein tension is applied to the metal filament between the constant tension applying device and the corrugating device. An apparatus for manufacturing a metal cord, comprising: an additional tension applying device for adding an additional tension.