JPH06116882A - Steel cord for tire and tire using the same - Google Patents

Abstract

PURPOSE:To obtain the steel cord low in the initial rate of extension under low load and having necessary rubber penetrability and to obtain the tire excellent in bond strength between rubber and the cord, by taking nonreformed, straight-line elemental wires in excessively reformed elemental wires followed by mutual twisting. CONSTITUTION:(A) Nonreformed, straight-line elemental wires, 1X3 to 5 steel cords, and (B) excessively reformed elemental wires are mutually twisted to obtain the objective steel cord 0.20-0.10 in the initial rate of extension.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a steel cord for a tire and a tire using the steel cord.

[0002]

2. Description of the Related Art Conventional steel cords for tires include a closed type and an open type. The open type has a moisture content that has penetrated into the space at the center of the cord, which is a problem with the closed type. In order to prevent rust from occurring, the strands are twisted together so that a gap remains between them, and the rubber penetrates and fills the space through this gap, eliminating the space where moisture can enter. It was devised to prevent the occurrence of.

However, even the above-mentioned conventional open type has the following problems that cannot be considered in the closed type.

That is, a gap is required between the individual wires so that the rubber enters the space at the center of the cord, and in order to secure this gap, an excessive habit is given to each of the individual wires over the entire length. Must. As a result, the twisted lengths of the individual strands become non-uniform, and as a result, a displacement occurs between the individual strands, and the longitudinal twist tends to be unstable, and the strands are particularly embedded in the tire. In such a case, since the initial elongation rate is large when a low load is applied, there is a problem that the gap is lost, the rubber infiltration property cannot be expected, and the workability when burying the cord becomes difficult.

[0005]

The problem to be solved by the invention is that a cord made of an excessively stiffened wire has a structurally large initial elongation under a low load, and a gap cannot be maintained. That is, it is not possible to obtain a required rubber penetration property, and it is not possible to obtain a tire in which the bonding strength between the rubber and the cord is excellent.

[0006]

In order to achieve the above-mentioned object, the steel cord is a steel cord of 1 × 3 to 5 and has a linear shape in which some strands to be twisted are not bent. It is characterized in that the initial elongation is 0.20 to 0.10% by twisting the unstretched linear filament and the excessively curled filament as a strand.

Further, the steel cord of the present invention is characterized in that the cord has a cross-sectional shape of a different shape crushed in the cross-sectional direction. Specifically, the cross-sectional shape of the cord is a flat shape such as an elliptical contour, and the cord is crushed by passing it between rollers and molded into an appropriate irregular shape.

If the initial elongation exceeds the upper limit of the above range, twisting of the wires is likely to occur, and if it does not reach the lower limit of the range, the gap between the wires becomes small. Poor rubber penetration when embedded in rubber. This initial elongation rate is preferably 0.18 to 0.12%.

In addition, the composition ratio of the excessively habitd wire and the non-habited wire may be, for example, a structure in which there are many habitus lines and there are few non-habited wires, or in the opposite structure. Alternatively, the same number of configurations may be used. Further, the diameters of the respective strands may be the same, or some of the strands may have a small diameter or a large diameter.

In the tire, in which the steel cord is embedded in the belt portion, the steel cord is a steel cord of 1 × 3 to 5, and the strand is excessively habitualized and the habitualization is performed. It is twisted with a straight wire that has not been twisted, the initial elongation is 0.20 to 0.10%, and between the overstretched wires in the cord,
Further, it is characterized in that they are integrally connected through a rubber penetrating from the gap between the strand and the straight strand which is not formed to the center of the cord.

[0011]

[Function] A cord is formed by twisting a straight wire that is not habit and a wire that is overly habit, and the initial elongation is 0.20 to 0.10%. Even at times, a gap is maintained between the strands, and the required rubber penetration can be obtained.

Since the cross-sectional shape of the cord has a different shape that is crushed in the cross-sectional direction, the excessively bent wire is further forcibly bent and plastically deformed from the bent shape. As compared with the non-crushed one, it is possible to firmly and firmly hold the gap in such a space that the rubber can penetrate.

In the tire, the steel cord embedded in the belt portion has a twisted cross-section structure of 1 × 3 to 5 and is composed of an excessively bent strand and a non-stretched straight strand. While twisting, the initial elongation is 0.20-0.
Through the rubber that penetrates to the center of the cord from the gap between each overstretched strand in the cord, and between this strand and the non-straightened straight strand, to 10% Since the wires are integrally connected, some of the wires of the cord are composed of wires that are excessively habitd, but they are bonded to the rubber in each wire unit, and the bonding strength between the cord and the rubber High and excellent in durability.

[0014]

1 and 2, there is illustrated a first embodiment of a steel cord for tires of the present invention. This 1 × 4 steel cord 1 is composed of three excessively bent elements. Line 1A
And one unstretched linear elemental wire 1B are twisted together, then passed through between rollers and crushed in the cross-sectional direction to form a cord cross-sectional shape into an elliptical shape. The initial elongation is set to 0.16%.

A gap S is provided between each of the three strands of wire 1A that are excessively bent, and between this straight strand of wire 1A and one straight wire 1B that is not bent. Has been formed. It is desirable that this gap S is 0.03 mm or more. The wire diameter of each strand 1A, 1B is 0.28 mm.

As a result, the unstretched linear strand 1B and the overstretched strand 1A are twisted together to form an initial elongation of 0.16%.
Even under a low load, the gap S is maintained between the wires 1A and 1B, and the required rubber penetration can be obtained.

Since the initial elongation is low, the workability during tire making is good.

Since the cross-sectional shape of the cord is an elliptical shape that is crushed in the cross-sectional direction, the strand 1A that is excessively bent is forcibly bent from the same bent state and plastically deformed. However, it is possible to firmly hold the gap S into which rubber can penetrate.

FIG. 3 illustrates a second embodiment of the steel cord for tire of the present invention. This 1 × 3 steel cord 1 has two strands 1A which are excessively bent, After untwisting with one straight strand 1B, the cord is crushed in the cross-sectional direction by passing it between rollers to form an elliptical cross-sectional shape. The initial elongation is set to 0.16%. The wire diameter of each strand 1A, 1B is 0.
28 mm.

A gap S is provided between each of the two strands of wire 1A that are excessively curled, and between this strand of wire 1A and one straight strand of wire 1B that is not curled. Has been formed. It is desirable that this gap S is 0.03 mm or more. The wire diameter of each strand 1A, 1B is 0.28 mm.

As a result, the same operational effect as that of the first embodiment is obtained.

FIG. 4 exemplifies a third embodiment of the steel cord for tires of the present invention. This 1 × 5 steel cord 1 has four strands 1A which are excessively bent, After untwisting with one straight strand 1B, the cord is crushed in the cross-sectional direction by passing it between rollers to form an elliptical cross-sectional shape. The initial elongation is set to 0.16%. The wire diameter of each strand 1A, 1B is 0.
25 mm.

A gap S is provided between each of the four strands 1A that are excessively bent, and between this strand 1A and one unstretched linear wire 1B. Has been formed. The gap S is preferably 0.05 mm or more. The wire diameter of each strand 1A, 1B is 0.25 mm.

As a result, the same operational effect as that of the first embodiment is obtained.

The following Table 1 shows a: closed code, b:
An initial elongation of 0.19 in which all strands have an excessive habit
% Open cord, c: cord of the first embodiment of the present invention, d: initial elongation of 0.11% from that of the first embodiment
The results of experiments on the rubber penetration of each cord having the same configuration except that Note that the tensile force when embedded in rubber was 20N.

[0026]

[Table 1]

As shown in Table 1, when a low load was applied, rubber penetration was lost not only in Comparative Example a but also in B, but it was confirmed that the present invention c and d had good rubber penetration. did.

FIG. 5 exemplifies a tire 2 in which the steel cord 1 of the first embodiment is embedded in the belt portion 3 and molded, and each strand 1A of the cord 1 which is excessively bent.
Between the wire 1A and the unstretched linear wire 1B, the rubber 4 which penetrates from the gap S to the cord central portion 1a is integrally connected.

As a result, although some of the strands of the cord 1 are composed of the strands 1A having an excessive tendency,
It is connected to rubber 4 in units of 1A and 1B, and cord 1 and rubber 4
Has high bond strength and excellent durability.

[0030]

【The invention's effect】

A. According to claim 1, a straight strand that is not habit-formed and a strand that is excessively habit-formed are twisted together, and the initial elongation is set to 0.20 to 0.10%. Even at times, a gap is maintained between the strands, and the required rubber penetration can be obtained.

B. Since the initial elongation rate is low due to
Good workability when making tires.

C. According to claim 2, since the cord cross-sectional shape is an elliptical shape crushed in the cross-section direction,
The strands with excessive habits are more forcibly bent from the same habitual state and plastically deformed, so that the gap can be securely and firmly inserted into the gap where rubber can penetrate, as compared to the uncrushed one. You can stick.

D. According to claim 3, since a part of the wire of the cord is composed of an excessively bent wire, but is bonded to the rubber in each wire unit, the bonding strength between the cord and the rubber is high and durable. It has excellent properties.

[Brief description of drawings]

FIG. 1 is a front view illustrating a first embodiment of a steel cord for tires of the present invention.

2A is an enlarged cross-sectional view taken along the line aa in FIG. 1, and FIG.
1 is a bb enlarged transverse sectional view of FIG. 1, (c) is a cc enlarged transverse sectional view of FIG. 1, (d) is a dd enlarged transverse sectional view of FIG.
1E is an enlarged cross-sectional view taken along the line ee of FIG. 1, and FIG.
-F enlarged transverse sectional view, (g) is a gg enlarged transverse sectional view of FIG. 1, and (h) is a hh enlarged transverse sectional view of FIG.

FIG. 3 is an enlarged cross-sectional view illustrating a second embodiment of the steel cord for tire of the present invention.

FIG. 4 is an enlarged cross-sectional view illustrating a third embodiment of the steel cord for tire of the present invention.

FIG. 5 is a partially enlarged cross-sectional view illustrating a tire of the present invention in which the steel cord of the first embodiment is embedded in a belt portion and molded.

[Explanation of symbols]

 1 Steel cord 1A Stranded wire 1B Unstretched wire 1a Cord center part 2 Tire 3 Tire belt 4 Tire rubber S Gap between cords

Claims (3)

[Claims] 1. A steel cord of 1 × 3 to 5 comprising:
Part of the strands to be twisted together is made into a straight strand that is not habitual, and this straight strand that is not habitual and the strand that is excessively stranded are twisted together, and the initial elongation is 0.20
Steel cord for tires characterized by ~ 0.10%. 2. The steel cord for a tire according to claim 1, wherein the cord has a cross-sectional shape that is an irregular shape that is crushed in the cross-sectional direction. 3. A tire having a steel cord embedded in a belt portion, wherein the steel cord is a 1 × 3 to 5 steel cord, and an excessively habitd strand and a non-habited strand. Between the overstretched strands in the cord, which are twisted with the straight strands and have an initial elongation of 0.20 to 0.10%, and between these strands and the unstretched straight strands A tire characterized in that it is integrally connected through a rubber that has penetrated from the gap between the wire to the center of the cord.