JPH0718102B2 - Multi-layer twisted steel cord for tires and tires - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-layer twisted steel cord for a tire and a tire which are used for reinforcing a tire.

(Prior Art) As a conventional multi-layer twist steel cord C for a tire, there is a one shown in FIG. 3, which has both inner twist layer 10 and outer twist layer 11 formed therein. Each of the wires 12 has a twisted structure that is in close contact with each other.

(Problems to be Solved by the Invention) By the way, in the above-mentioned multi-layer twisted steel cord having a twisted structure, the wires in both layers are in close contact with each other, and there is no gap between the wires. It cannot be expected to grow in the direction.

A study on the fact that the axial extension is zero or close to zero in relation to the riding comfort of a car shows that there is no effect when the road surface is flat, but there is unevenness. In some cases, the rubber does not stretch relative to the unevenness, but the cord does not stretch, and as a result, there is a problem peculiar to hard riding comfort caused by a shock due to the step of the unevenness.

Also, since the individual wires of the lower twisted layer and the upper twisted layer are in close contact with each other with no gaps between them, it is difficult for rubber to penetrate into the inside of the cord. There is a problem that wear fatigue due to coating and corrosion fatigue due to moisture entering from the outside into the space between the strands are likely to occur, resulting in poor fatigue performance.

There is also a multi-layer twisted steel cord described in JP-A-56-163905, but this cord also has a structure in which the strands in the lower twisted layer are in close contact with each other without a gap and extensibility cannot be expected. In the end, the cord cannot be expected to grow in the axial direction as a whole.

In this respect, the steel cord described in Japanese Utility Model Application No. 55-74997 (Japanese Utility Model Application No. 57-1898) has a gap between each strand in both the core strand and the side strands. Since the circumscribed circle and the inscribed circle of the side strand are closely twisted, it is not possible to expect smooth stretchability of the entire cord. In addition, the core strand receives a compressive force when the side strands are twisted together, and the gap is closed, so that the elongation of the entire cord cannot be expected and the bondability with rubber cannot be expected.

The present invention has been made in view of such circumstances, and the entire cord including the lower twisted layer and the upper twisted layer has smooth stretchability in the axial direction and includes the layers of the upper twisted layer and the lower twisted layer. The purpose of the present invention is to provide a multi-layer twisted steel cord for a tire, in which all the individual wires of both layers can be bonded to rubber. Furthermore, by using this multi-layer twisted steel cord, a tire having improved riding comfort and durability can be obtained. The purpose is to provide.

(Means for Solving the Problems) In the multi-layer twisted steel cord for tires of the present invention, a multi-layer twisted steel cord for tires formed by parallel twisting an inner twist layer and an appropriate number of outer twist layers. The upper twisted layer and the lower twisted layer are characterized in that there is a gap between both layers and between the wires of each layer so as to communicate with each other.

In the tire, the multilayer twisted steel cord in the carcass has an inner twist layer which is twisted in parallel and an appropriate number of outer twist tanks on the outside, and between this upper twist layer and the lower twist layer and between each layer. It is characterized in that there are mutually communicating gaps between the strands and that the gaps are filled with rubber.

Further, the diameter of the steel cord is related to the tire size. For example, a large tire having a large strand diameter and a small tire having a thin strand diameter are targeted.

Further, in the multi-layer twisted steel cord, the number of layers of the lower twisted layer and the upper twisted layer is arbitrary, and the number of constituent strands of each layer is also appropriately selected.

Also, regarding the tire size, any of large size, normal size and small size can be selected.

(Operation) Since the lower twisted layer and the upper twisted layer are twisted in parallel to each other and have intercommunication gaps between the wires of both layers and each layer,
Each strand only has a uniform habit (with a mold) in the direction when it is twisted with the final twist, and it does not have a twisted structure that entangles or abuts, and the entire cord smoothly in the axial direction. It is stretchable and stretches with a flexible elastic rubber, and since it is rich in flexibility, it stretches and bends integrally with the rubber.

Although the individual wires are displaced from each other, the rubber penetrates through the gaps that are in communication with each other and fills up to the center of the cord, so wear fatigue due to fretting and corrosion fatigue due to moisture do not occur, and durability Excellent in performance.

Further, since the lower twisted layer and the upper twisted layer are twisted in parallel, the fatigue performance is improved, the fatigue property is excellent, and the twisting can be performed in one twisting operation, resulting in good productivity.

Since the multi-layer twisted steel cord embedded in the tire and reinforcing the tire has good extensibility, flexibility, and fatigue resistance, it can stretch or bend a shock during running on a bumpy road surface. Absorb.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

Multi-layer twisted steel cord A for tires illustrated in FIG.
Is a parallel twist of an inner twist layer 2 made of three strands 1 and an outer twist layer 3 made of nine strands 1.

Then, the wires 1 in the layers 2 and 3 can move in such a manner that a gap a is formed between all the wires adjacent to each other in the circumferential direction and the radial direction of the cross section, and the wires 1 close the gap a. Thus, the entire cord is stretchable in the axial direction.

The gap a communicates with each other between the individual strands 1 in the outer twisted layer 3, the layer between the inner twisted layer 2 and the strands 1 including the central portion al in the lower twisted layer 2. All the gaps a and the central portion al are filled with rubber so that it can be filled.

Further, although the 3 + 9 mode is illustrated in the drawings, other modes such as 3 + 9 + 15 are optional.

The tire B illustrated in FIG. 2 is molded into a desired tire shape using the multi-layer twisted steel cord A illustrated in FIG. 1, and the rubber 4 of the carcass B1 is formed by the pressure during molding.
Fills the gaps 1 from the outside of the upper twisted layer 3 to fill the central portion al, and all the strands 1 are wrapped in the rubber 4 and separated from each other in a non-contact manner.

Then, each strand 1 of the lower twisted layer 2 and the upper twisted layer 3 is stretchable in the axial direction together with the flexible elastic rubber 4 filling the gap a including the central portion al.

Next, the multilayer twisted steel cord A of the present invention illustrated in FIG.
The manufacturing method of will be described.

(Not shown) The under-twisted strand 1 is passed through a core rotating slab through a feeder, and the lower twist layer 2 in which a gap a is formed between the strands 1 is twisted by the rotating slat.

In parallel with this, the twisted strands 1 are passed through a twisting device through a twisting rotary twisting plate, and the twisting layer 3 in which gaps a are formed between the twisted strands 1 is twisted by the twisting twisted plate. It

In the lower twisting and the upper twisting, the lower twisting layer 2 is passed through the center of the upper twisting rotary eye plate and simultaneously twisted in parallel to manufacture the multilayer twisted steel cord A.

The elongation percentage of the multi-layer twisted steel cord A can be set to a desired value by adjusting the rotary eye plate.

(Effects of the Invention) Therefore, the present invention has the following advantages.

Since the lower twisted layer and the upper twisted layer are twisted in parallel and have a gap between each of the layers and the wires of each layer that are in communication with each other, each wire is oriented in the direction when it is twisted in the final twist. Only with a uniform habit (with a mold), it does not have a twisted structure that entangles or abuts, the whole cord can be smoothly extended in the axial direction, and it can extend with a flexible elastic rubber, Moreover, since it is rich in flexibility, it can flexibly extend and bend integrally with the rubber. Further, since the lower twisted layer and the upper twisted layer are twisted in parallel, the fatigue performance is improved, the fatigue property is excellent, and the twisting can be performed in one twisting operation, resulting in good productivity.

Although the individual wires are displaced from each other, the rubber penetrates through the gaps that are in communication with each other and fills up to the center of the cord, so wear fatigue due to fretting and corrosion fatigue due to moisture do not occur, and durability It has excellent properties.

Also, since the lower twist layer and the upper twist layer are twisted in parallel,
Fatigue performance is improved and fatigue resistance is excellent, and since it can be twisted in one twisting operation, it has good productivity.

The multi-layer twisted steel cord that is embedded in the tire and reinforces the tire has good stretchability, flexibility and fatigue resistance, so it absorbs shock by stretching or bending when driving on uneven road surfaces. Therefore, riding comfort and durability can be improved, and at the same time, it can contribute to protection of cargo.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing an embodiment of the multi-layer twisted steel cord for tire of the present invention. FIG. 2 is a partially enlarged cross-sectional view of a tire using the multi-layer twisted steel cord of FIG. FIG. 3 is an enlarged cross-sectional view showing a conventional multi-layer twist steel cord for a tire, and FIG. 4 is a partially enlarged cross-sectional view of a conventional tire using the same steel cord. In the figure, A is a multi-layer twisted steel cord B is a tire B1 is a carcass a is a gap al is the central part of the lower twisted layer 1 is an element wire 2 is a lower twisted layer 3 is an upper twisted layer 4 is rubber

Claims (2)

[Claims] 1. A multi-layer twisted steel cord for a tire, which is formed by parallel twisting an inner twist layer and an appropriate number of outer twist layers, wherein the upper twist layer and the lower twist layer are both layers. And a multi-layer twisted steel cord for a tire, characterized in that all the strands of each layer have a communicating gap. 2. A multi-layer twisted steel cord in a carcass having a parallel twisted inner twist layer and an appropriate number of outer twist layers, and between each twist layer and each twist layer. A tire characterized in that it has a communication-like clearance between all the strands, and that the clearance is filled with rubber.