JPH05279973A - Multilayer twisted steel cord for rubber elastomer - Google Patents

Abstract

PURPOSE:To provide the subject twisted steel cord excellent in twist stability, rubber impregnability to the center cavity of the cord and elongation under low load. CONSTITUTION:The core layer of the subject multilayer twisted steel cord is composed of >=3 strands twisted with each other. At least one of the strands has wavy bent form along its length to form rubber-intrusion openings between the adjacent strands. One or plural layers outside of the core layer have rubber- intrusion gaps between the strands constituting the layers or rubber-intrusion openings formed by bent parts similar to the opening on the core layer. The rubber-intrusion openings of the core layer are connected to the rubber-intrusion gaps or the rubber-intrusion openings of the outer layer in a state to form radially interconnected channels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer twisted steel cord embedded in a rubber elastic body such as a tire or a conveyor belt.

[0002]

2. Description of the Related Art A conventional multi-layer twisted steel cord has a structural problem in that moisture penetrates into a cavity at the center of the cord surrounded by each wire in the center layer to cause rusting. There was an inevitable inconvenience of tire separation.

As a means for solving this problem, a structure of a conventional open twisted steel cord can be considered.

That is, in order to facilitate the infiltration of rubber into the cavity of the central layer, it is sufficient to secure a gap between the individual wires forming the same layer and between the individual outer wires of each layer.
To secure the gap, it is necessary to give each strand an excessive habit over its entire length. As a result, the twisted lengths of the individual wires become non-uniform, and as a result, the twisting of the center layer becomes unstable, making it difficult to form a multilayer twisted cross-section structure. Moreover, there is a displacement between the strands, which makes the twisting unstable in the longitudinal direction, which causes the strands to move in and out at the cut surface, and the elongation under a low load becomes large. There is a problem that sex becomes difficult.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a stable center layer twist, rubber penetration, and low load elongation. The present invention is also intended to provide a multi-layer twisted steel cord for rubber elastic body.

[0006]

In the multilayer twisted steel cord for rubber elastic body of the present invention, at least one strand is bent along the line direction in the center layer formed by twisting three or more strands. The portion is repeatedly formed, and has a rubber entrance between the bent portion and a wire portion adjacent to the bent portion, and the layer outside the central layer is at least one of the wires forming the same layer. It is characterized in that there is a rubber intrusion gap between some of the wires, and the rubber intrusion gap in the central layer and the rubber intrusion gap in the outer layer are adjacent to each other in communication with the inside and outside.

Further, in the present invention, in a multi-layer twisted steel cord, at least one element wire in a center layer formed by twisting three or more element wires and each layer in a single layer or a plurality of layers outside the center layer are provided. At least one of the strands
Each of the strands of the book has a bent portion repeatedly formed along the line direction, and has a rubber entrance between the bent portion and an adjacent wire portion. The rubber entrance in the central layer and the outer layer It is characterized in that the rubber entrance in is adjoined to the inside and outside in a communicating manner.

Further, the present invention provides a multi-layer twisted steel cord in which at least one element wire in a center layer formed by twisting three or more element wires and each layer in one or more intermediate layers outside the center layer. At least one of the strands of No. 1 has a bent portion repeatedly formed along the line direction, and has a rubber entrance between the bent portion and a portion of the strand of wire adjacent to the bent portion. The outer layer outside the layer has a rubber penetration gap between at least some of the wires forming the same layer, and has a rubber entrance in the center layer and a rubber entrance in the middle layer. It is characterized in that the rubber intrusion gap in the outer layer is adjacent to the inside and outside in a communicating manner.

The rubber entry port and the rubber entry gap are preferably 0.05 mm or more. The pitch of each layer and the bent portion between the layers is the same as the longitudinal direction of the cord and is adjacent to each other in the circumferential direction, or is displaced in the longitudinal direction and is adjacent to each other in the circumferential direction. There may be no aspect. Further, the pitch of the bent portions is not limited to the equal pitch, and can be freely set.

[0010]

Function: The twisting of the center layer, which is formed by twisting three or more strands, is stable, and the rubber entry port in this center layer communicates with the rubber entry gap of the outer layer or with the rubber entry port inside and outside. Therefore, the rubber penetrates from the rubber penetration gap or the rubber entrance of the outer layer to the cavity entrance at the center of the cord through the rubber entrance of the central layer to fill the cavity.

As a result, a multi-layer twist cross-section structure is exhibited,
In addition to the advantages unique to this structure, tire separation due to rusting of the hollow portion at the center of the cord can be avoided.

[0012]

1 and 2 show a first embodiment of a multi-layer twisted steel cord in the case where the rubber elastic body is a large tire. It is composed of a layer 2 and an outer outer layer 3. Regarding the twisting directions of the center layer 2 and the outer layer 3, the center layer 2 is Z-twisted and the outer layer 3 is S-twisted.

The central layer 2 is formed by tightly twisting two linear strands 2a and one strand 2b having a bent portion A, which will be described later, in a twisted cross-sectional shape of a triangle. One of the strands 2b is formed by repeatedly forming a bent portion A along the line direction, and at each bent portion A, a rubber entry port a is formed between the adjacent wire portion. , And the wires 2a, 2b are in close contact with each other except for the rubber entrance a.

The outer layer 3 has a rubber penetration gap b between each of the six parallel strands 3a forming the same layer in the spiral direction, and a part of the rubber penetration gap b is formed. Central layer 2
In the embodiment, the rubber is adjoined to the inside and outside of the rubber entrance port a in a manner such that the rubber can enter and fill the cavity B of the communication form from the rubber entrance gap b through the rubber entrance port a. There is.

The diameter of the wires 2a and 2b in the central layer 2 is 0.20 mm.
The pitch of the bent portion A is 3.1 mm, and the diameter of the wire 3a in the outer layer 3 is 0.35 mm.

The multilayer twisted steel cord 1 for a tire according to the second embodiment illustrated in FIG. 3 has basically the same configuration as that of the first embodiment, and therefore a description of the common configuration will be given. The different configuration will be described by omitting it.

The outer layer 3 is formed by tightly twisting four linear strands 3a and two strands 3b having a bent portion A, which will be described later, and the two strands 3b are The bent portion A is repeatedly formed by patterning along the line direction. And the central layer 2
The two relative strands of wire 3b between them form a rubber entrance a at each bent portion A between the wire and an adjacent wire portion,
The wires 3a and 3b are in intimate contact with each other except the rubber entrance a.

The rubber entrance a in the outer layer 3 is in a state of being adjacent to the rubber entrance a in the center layer 2 so as to communicate with the inside and the outside, and the cavity B which is in communication with the rubber entrance a inside and outside. It is designed so that rubber can invade and fill.

The diameter of the wires 2a and 2b in the central layer 2 is 0.20 mm.
The diameter of the wires 3a and 3b in the outer layer 3 is 0.38 mm, and the pitch of the bent portion A of the wire 2b is 3.1 mm and the pitch of the bent portion A of the wire 3b is 6.3 mm.

The multi-layer twisted steel cord 1 for tire of the third embodiment illustrated in FIG. 4 has basically the same construction as that of the second embodiment. Therefore, the explanation of the common construction will be given. The different configuration will be described by omitting it.

The multi-layer twisted steel cord 1 is a three-ply twisted cord and is composed of a center layer 2, an intermediate layer 4 and an outer layer 3.
Regarding the twisting directions of the central layer 2, the intermediate layer 4, and the outer layer 3, the central layer 2 is S-twisted, the intermediate layer 4 is S-twisted, and the outer layer 3 is Z-twisted.

The intermediate layer 4 is formed by tightly twisting four linear strands 4a and four strands 4b having a bent portion A, which will be described later, in an alternating state. The element wire 4b is formed by repeatedly forming a bent portion A along the line direction.
Then, each of the four wires 4b forms a rubber entrance a at each bent portion A between the wire and an adjacent wire part, and the wires 4a and 4b are apart from each other except the rubber entrance a. Without close contact.

The outer layer 3 is formed by tightly twisting six linear wires 3a and seven wires 3b having a bent portion A, which will be described later, alternately in a tightly twisted state. The strand 3b is formed by repeatedly forming a bent portion A along the line direction. Then, each of the seven wires 3b forms a rubber entrance a at each bent portion A between the wire and the adjacent wire, and the wires 3a and 3b are in close contact with each other except the rubber entrance a. Are in contact with each other.

The rubber entrance a in the outer layer 3 passes through the rubber entrance a in the intermediate layer 4 and then the rubber entrance a in the center layer 2.
In this embodiment, the rubber is adjacent to the inside and outside in a communicating manner, and the rubber can enter and fill the communicating cavity B through the rubber entrance a inside and outside.

Diameters of the wires 2a, 2b in the central layer 2, diameters of the wires 4a, 4b in the intermediate layer 4, and wires 3a, 3b in the outer layer 3
The diameter of each is 0.22 mm, and the pitch of the bent portion A of each layer is 3.1 mm for the wire 2b, 4.7 mm for the wire 4b, and 6.3 m for the wire 3b.
m.

The multilayer twisted steel cord 1 for a tire of the fourth embodiment illustrated in FIG. 5 is basically the same in construction as that of the third embodiment, so a description of the common construction will be given. The different configuration will be described by omitting it.

The outer layer 3 has a rubber penetration gap b between each of the 13 parallel strands 3a forming the same layer, and all the rubber penetration gaps b are intermediate. Layer 4
Of the central layer 2 through the rubber entry port a, and is in communication with and adjacent to the inside and outside of the central layer 2. The cavity section B communicates with the rubber entry gap b through the rubber entry port a inside and outside. It is designed so that rubber can invade and fill.

The diameters of the strands 2a and 2b in the central layer 2, the diameters of the strands 4a and 4b in the intermediate layer 4, and the diameter of the strands 3a in the outer layer 3 are all 0.175 mm. The pitch is 3.1 mm for the wire 2b and 4.7 mm for the wire 4b.

Table 1 shows the data of twist stability, low load elongation (initial elongation), and rubber penetration of the multi-layer twisted steel cords 1 of the first to fourth examples, which are the conventional multi-layer twists. It is shown in comparison with the steel cord.

[0030]

[Table 1]

As shown in the above table, the product of the present invention has good twist stability, has the advantages of a multi-layer twisted cord, has good rubber penetration, and has a small initial elongation and a small amount.

The above embodiment shows one example of the present invention. As another example, the number of the strands 2b having the bent portion A of the central layer 2 in the first to fourth embodiments is increased. Or to increase or decrease the number of the strands 3b, 4b having the bent portion A in the outer layer 3 of the second embodiment, the intermediate layer 4 and the outer layer 3 of the third embodiment, and the intermediate layer 4 of the fourth embodiment, etc. You may. In addition, the structure of two-layer twist is 3 + 7, 3 + 8, 3 + 9, 4 + 9
Etc., or 3 + 9 + 15, 4 + 9 + 13 with three layers twisted
Etc., and it is optional to use three or more layers.

[0033]

【The invention's effect】

I. The twisting of the center layer, which is twisted with three or more strands, is stable, and the rubber entry port in this center layer communicates with the rubber entry gap of the outer layer or with the rubber entry port inside and outside. Can be filled from the rubber penetration gap or the rubber penetration hole of the outer layer to the hollow part at the center of the cord through the rubber penetration hole of the central layer.

B. By presenting a multi-layer twisted cross-section structure, the structure has the advantages peculiar to the structure, and tire separation due to rusting of the hollow portion at the center of the cord can be avoided. In addition, it has little elongation under low load and is excellent overall.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a multilayer twisted steel cord for rubber elastic body of the present invention.

FIG. 2 is a partial front view of a wire having a bent portion in the cord of FIG.

FIG. 3 is a cross-sectional view showing a second embodiment of the multilayer twisted steel cord for rubber elastic body of the present invention.

FIG. 4 is a cross-sectional view showing a third embodiment of the multilayer twisted steel cord for rubber elastic body of the present invention.

FIG. 5 is a cross-sectional view showing a fourth embodiment of the multilayer twisted steel cord for rubber elastic body of the present invention.

[Explanation of symbols]

1 Multi-layer twisted steel cord 2 Center layer 3 Outer layer 4 Intermediate layer 2a, 3a, 4a Strands without bends 2b, 3b, 4b Strands with bends A Bends B Cavities a Rubber entry b Rubber entry gap

Claims (3)

[Claims] 1. In a multi-layered steel cord, 3
At least 1 core layer is made of two or more strands
The strands of the book form bent portions repeatedly along the line direction, and have a rubber entry port between the bent portions and adjacent strand portions, and the outer layer of this center layer is the same layer. There is a rubber intrusion gap between at least some of the formed wires, and the rubber intrusion opening in the center layer and the rubber intrusion gap in the outer layer are adjacent to each other inside and outside. A multilayer twisted steel cord for a rubber elastic body, characterized in that 2. In a multi-layer twisted steel cord, 3
At least one strand in the central layer formed by twisting two or more strands together, and at least one strand in each layer in the single or multiple layers outside the central layer, Repeatedly forming a bend along the direction,
A rubber entry port is provided between the bent portion and the adjacent wire portion, and the rubber entry port in the central layer and the rubber entry port in the outer layer are adjacent to each other in communication with the inside and outside. A multi-layer twisted steel cord for rubber elastic bodies. 3. In a multi-layer twisted steel cord, 3
At least one strand in the central layer formed by twisting two or more strands, and at least one strand in each of the layers in the intermediate layer or layers outside the central layer, A bent portion is repeatedly formed along the line direction, and a rubber entrance is provided between the bent portion and a wire portion adjacent to the bent portion. The outer layer outside these intermediate layers is each element forming the same layer. There is a rubber penetration gap between at least some of the wires, and the rubber penetration hole in the central layer, the rubber penetration hole in the middle layer, and the rubber penetration gap in the outer layer are adjacent to each other in communication with the inside and outside. A multilayer twisted steel cord for a rubber elastic body, characterized in that