JP4357015B2 - Steel cord for reinforcing rubber products - Google Patents

Description

【００２３】
この評価に際して、ゴム材の浸入性は各コードに５ｋｇの引張荷重をかけた状態でゴム材中に埋め込み、加圧加硫した後コードを取り出し、そのコードを分解して一定長さを観察し、観察した長さに対してゴム材と接触した形跡のある長さの比をパーセント表示して比較した。
【００２４】
低荷重の伸びは、５ｋｇ荷重時の各コードの伸びを示し、取扱作業性および撚りの安定性上低い値であることが好ましい。
また、取扱作業性は、クローズドコードに比べて同等の作業性を有するものを○、劣るものを×とした。
【００２５】
上記評価より、本発明のコードのゴム材の浸入性は、従来コードであるクローズとコードと比べ格段に向上しており、オープンコードとは差はなく、撚りの安定性もクローズドコードと変わりないことからゴム製品の補強材として最適であることが判明した。
【００２６】
ところで、上記本発明のコードを、断面形状が略楕円形となるように加工したコードにおいても同等の効果を得ることができた。
【００２７】
【発明の効果】
本発明の効果は、撚り構造が安定しているので取扱作業性に優れ、また素線間に隙間を有するのでゴム材がコード内に確実に浸入しコードとゴム材の完全な複合体となる。このため、例えばこのコードをタイヤに使用した場合、フレッティング摩耗、セパレーツ現象および腐食によるコードの強力低下等を防止できる。
さらに、このコードを、長さ方向に同一向きの略楕円形状とすることで、短径軸側をタイヤの厚み方向に配置することにより、タイヤの厚みを薄くすることが可能となり、タイヤの軽量化が図れ、自動車の省エネ効果にもつながるという優れた効果を奏する。
【図面の簡単な説明】
【図１】（ａ）〜（ｄ）は、本発明のスチールコードの実施例を示す概略断面図である。
【図２】（ａ）、（ｂ）は、本発明のスチールコードの別の実施例を示す概略断面図である。
【図３】本発明のスチールコードの要部を示す説明図である。
【図４】（ａ）〜（ｂ）は、従来のスチールコードの例を示す概略断面図である。
【符号の説明】
１、２、３、４、７、８、１１、１２スチールコード
５、９ スパイラル素線
６、１０、１３ 非スパイラル素線
Ａ スパイラル素線によって形成される空間
Ｃ、Ｌ 隙間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steel cord for reinforcing rubber products (hereinafter simply referred to as “cord”) used as a rubber product reinforcing material for automobile tires, conveyor belts and the like.
[0002]
[Prior art]
Generally, a so-called closed twisted cord in which 3 to 6 strands are closely twisted together is used for this type of cord. These cords are covered with rubber in a state in which a plurality of cords are arranged in parallel, and are used as rubber product reinforcing materials such as automobile tires and conveyor belts.
[0003]
By the way, an indispensable requirement as a rubber product reinforcing material is excellent fatigue resistance. In other words, if the cord has excellent strength and is a complete composite with rubber and has excellent fatigue resistance, it will greatly extend the life of the rubber product and increase safety, and it will serve as a rubber product reinforcement. Can be fulfilled sufficiently.
However, in the above cord, since the strands constituting the cord are in close contact and twisted together, the rubber may penetrate into the cord from between the strands when forming the composite sheet of cord and rubber. However, it merely covers the outer periphery of the cord, and a hollow portion continuously exists in the cord along the length of the cord.
[0004]
For this reason, when this cord is used for a tire, for example, the adhesion between the rubber and the cord becomes insufficient, so that the cord and the rubber are peeled off when the vehicle is driven, so that a so-called separation phenomenon is caused, and the function of the tire is remarkably reduced. Moisture in rubber and water that has penetrated from the tire scraps reach into the cavity inside the cord and propagates in the longitudinal direction of the cord to corrode the cord, leading to a decrease in the mechanical strength of the cord and greatly increasing fatigue resistance. Will be reduced.
[0005]
In recent years, a cord having a structure capable of improving the adhesion between the cord and rubber has been proposed.
[0006]
For example, cords 11 and 12 referred to as so-called open twisted cords that are not twisted and twisted while providing a gap C between the strands 13 and 13 as shown in FIG. 4 are disclosed.
In the cords 11 and 12, the gap C between the strands 13 and 13 needs to be 0.02 mm or more in order for the rubber to sufficiently enter the cord.
However, if the gap C is sufficiently large, the free space in which each strand 13 can move becomes large, the twisted structure tends to become unstable at the time of manufacturing the cord, the strands are displaced, and the twist is in the longitudinal direction of the cord. Or become uneven.
[0007]
In addition, since this cord has a large elongation at an extremely low load, not only the handling property and workability at the time of forming the composite sheet are bad, but the gap C is reduced by the low load tension applied at the time of forming the composite sheet, Eventually, it was the same as the closed cord, and the rubber did not sufficiently penetrate into the inside of the cord, so that it did not become a complete composite with the rubber, resulting in the above-mentioned adverse effects.
[0008]
[Problems to be solved by the invention]
This invention is made | formed in view of the said prior art, and makes it a subject to provide the steel cord which was excellent in rubber penetration property, and whose twist structure was stable.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention relates to a spiral steel cord having a 1 × n structure in which at least one of n (n = 3 to 6) strands has a small spiral shape. in the space formed by the habit of Jo, a portion of the strand having no habit small wire or spiral having a habit small other spiral is partly penetrated at different positions in the code longitudinal direction The element wires are engaged with each other .
[0010]
The cord of the present invention does not have a spiral-like small mark adjacent to the spiral element wire in a space formed by a spiral- shaped element wire (hereinafter referred to as “spiral element wire”). It is a cord in which a strand (hereinafter referred to as “non-spiral strand”) or a part of a spiral strand is inserted. And the code | cord | chord which existed partially exists in the position where the code | cord | chord longitudinal direction differs.
[0011]
According to the cord of the present invention, the rubber material enters from the gap formed by the spiral strands and is twisted so that other spiral strands or non-spiral strands enter the space formed by the spiral strands. For this reason, the strands are substantially engaged with each other, so that they are closer to the cord of the closed structure, and the twisted structure is stabilized.
[0012]
In the present invention, a gap Lmm between a spiral wire and a non-spiral wire or a spiral wire that has entered into a space formed by the spiral- shaped bead is L = 0.05d to 1.0d (d: wire diameter) ) Is preferable. This is because if L is less than 0.05d, the penetration of the rubber material is reduced, and if it is greater than 1.0d, the gap becomes too large and the twisted structure becomes unstable. The cord of the present invention may have a cross-sectional shape that is substantially elliptical in the same longitudinal direction.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
1A to 1D are sectional views of the cord of the present invention. The cords 1, 2, and 3 shown in (a) to (c) have a 1 × 3, 1 × 4, and 1 × 5 structure having one spiral wire, and the cord 4 shown in (d) has two cords. It is a 1 * 6 structure code | cord | chord which has a spiral strand.
FIGS. 2A and 2B are cross-sectional views of a cord showing another embodiment of the present invention. The cord 7 shown in FIG. 2A has a 1 × 4 structure, and the cord 8 shown in FIG. The structure has a substantially elliptical cross section.
[0015]
In all of the cords shown in FIGS. 1 (a) to 1 (d) and FIGS. 2 (a) and 2 (b), a non-spiral strand enters a space formed by the spiral strands in twisting. The structure is twisted together.
[0016]
By the way, when a non-spiral strand enters into the space formed by the spiral strand, the non-spiral strand enters the space (shaded portion A) formed by the spiral strand 9 as shown in FIG. It means that a part of 10 has entered. The clearance between the spiral strand 9 and the non-spiral strand 10 is L.
Although FIG. 3 shows a case where the strand that enters is a non-spiral strand, this may be a spiral strand.
[0017]
In order to insert a part of the adjacent strands into the space formed by the spiral strands, after twisting them with a twisting machine, they are passed through a die having a diameter slightly smaller than the cord diameter, or a plurality The individual rollers can be passed between the straightening rollers arranged in a staggered manner, and the amount of the gap can be adjusted by changing the spiral diameter or the straightening pressure. In addition, the small spiral in the present invention is different from the twist for twisting and does not require an exact spiral, and even if it is simply wavy, it is equivalent to the spiral In order to show the effect of this, such a shape is also included.
[0018]
If the wire diameter d is less than 0.15 mm, the strength of the steel cord is insufficient, and if it exceeds 0.40 mm, the flexibility is inferior, and therefore it is preferably in the range of 0.15 to 0.40 mm.
[0019]
In the cord of the present invention, a rubber material enters from a gap formed by a spiral element and a non-spiral element or a spiral element and a spiral element, and the spiral element is inserted into a space formed by the spiral element. Since the spiral or non-spiral strand adjacent to the wire enters, the twisted structure of the cord is stabilized.
[0020]
【Example】
Examples of the present invention will be specifically described below in comparison with conventional examples and comparative examples.
[0021]
Table 1 repeats the patenting and drawing process of 5.5φ wire rods to produce 0.25mm diameter strands with brass plating on the surface, and 3, 4, 5 and 6 of them are buncher twisted This is a result of trial production of a cord twisted with a wire machine. The cord based on this invention was obtained by passing through a die after twisting.
The gap L between the spiral strand and the strand entering the space formed by the spiral strand is changed, and the embodiment satisfying the conditions of the present invention, the comparative example deviating from the embodiment of the present invention, and the conventional Cords were manufactured and the stability of the twisted structure and rubber penetration were compared for each cord.
The stability of the twisted structure was determined by low load elongation (elongation at 5 kg load) and handling workability.
[0022]
[Table 1]

[0023]
At the time of this evaluation, the penetration property of the rubber material was embedded in the rubber material with a tensile load of 5 kg applied to each cord, and after pressure vulcanization, the cord was taken out, the cord was disassembled, and a certain length was observed. The ratio of the length of traces in contact with the rubber material to the observed length was displayed as a percentage.
[0024]
The low load elongation indicates the elongation of each cord under 5 kg load, and is preferably a low value in terms of handling workability and twist stability.
In addition, the handling workability was evaluated as ○ when the workability was equivalent to that of the closed cord, and x when it was inferior.
[0025]
From the above evaluation, the rubber material penetration of the cord of the present invention is significantly improved compared to the conventional cord and closed cord, there is no difference from the open cord, and the twist stability is the same as the closed cord This proved to be the most suitable as a reinforcing material for rubber products.
[0026]
By the way, the same effect can be obtained even in the cord obtained by processing the cord of the present invention so that the cross-sectional shape is substantially elliptical.
[0027]
【The invention's effect】
The effect of the present invention is that the twisted structure is stable, so that it is excellent in handling workability, and since there is a gap between the strands, the rubber material surely enters the cord and becomes a complete composite of the cord and the rubber material. . For this reason, for example, when this cord is used for a tire, it is possible to prevent fretting wear, a separate phenomenon, and a strength reduction of the cord due to corrosion.
Furthermore, by making this cord into a substantially oval shape in the same direction in the length direction, it becomes possible to reduce the thickness of the tire by disposing the minor axis side in the tire thickness direction, thereby reducing the weight of the tire. It has an excellent effect that it can be used to save energy in automobiles.
[Brief description of the drawings]
1A to 1D are schematic cross-sectional views showing an embodiment of a steel cord of the present invention.
FIGS. 2A and 2B are schematic cross-sectional views showing another embodiment of the steel cord of the present invention.
FIG. 3 is an explanatory view showing a main part of a steel cord of the present invention.
4A and 4B are schematic cross-sectional views showing examples of conventional steel cords.
[Explanation of symbols]
1, 2, 3, 4, 7, 8, 11, 12 Steel cord 5, 9 Spiral strand 6, 10, 13 Non-spiral strand A Space C, L formed by spiral strand

Claims (3)

In a steel cord having a 1 × n structure in which at least one of n (n = 3 to 6) strands has a spiral- like small crease, other spaces are formed in the space formed by the spiral crease. A part of a wire having a small spiral- like wire or a portion of a wire not having a small spiral- like wire partially enters at different positions in the cord longitudinal direction , and the wires engage with each other. Steel cord for reinforcing rubber products. Spiral Jomotosen the gap Lmm with its spiral intruding wire in the space formed by the habit of, L = 0.05d~1.0d (d: wire diameter) is claimed in claim 1, Steel cord for rubber reinforcement. Before SL cross-sectional shape of the steel cord, rubber products for reinforcing steel cord according to claim 1 or 2 which is substantially elliptical substantially the same orientation in the code longitudinally.

Images