JP2563933Y2 - Tire reinforcement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention mainly relates to a tire reinforcing material disposed on a belt portion and a carcass portion of a tire.

(Conventional technology and its problems) Conventionally, as this type of reinforcing material, a stranded wire called a so-called steel cord in which a plurality of thin steel wires having a wire diameter of 0.15 to 0.40 mmφ are stranded is used.

In general, the above-mentioned steel cord is obtained by repeatedly performing heat treatment such as lead patenting and wire drawing on a wire material, applying brass plating, performing wire drawing to a predetermined wire diameter to obtain a wire, and then obtaining the wire. Are manufactured by twisting a plurality of them.

By the way, indispensable requirements as a tire reinforcing material include not only having strength enough to withstand internal pressure and external force, but also having excellent flexibility.

In the above-mentioned steel cord, since the strand is inferior in flexibility in terms of strength as compared with the filament strand of nylon, polyester, etc., the flexibility is improved by twisting a plurality of strands, and tire riding is improved. It is intended to provide good comfort and steering stability. However, there is a problem that it cannot be easily and inexpensively manufactured because the twisting step is required.

Also, when the above steel cord is used as a reinforcing material for tires, the strands are worn due to friction between the strands, and the strands are closely adhered and twisted, so that rubber can penetrate into the cord. However, there is a problem that the wires are not covered with the rubber, and the wires rust due to the moisture in the rubber or the moisture permeated from the outside.

In view of the above problems, in recent years, various tire reinforcing materials having a single-wire structure that can be manufactured at low cost without requiring a twisting step, have good adhesion to rubber, and have excellent flexibility have been proposed.

For example, Japanese Unexamined Utility Model Publication No. 60-110497 discloses a flat wire with a corrugation in the thickness direction.

(Problem to be Solved by the Invention) The above-mentioned conventional reinforcing material for a tire is obtained by corrugating the flat steel wire up and down in the thickness direction, thereby improving flexibility and elongation at break. , To extend the life of the tire.

However, the above-mentioned tire reinforcing material is excellent only in flexibility in one direction, that is, in the vertical direction of the flat steel wire, and has a problem in elongation characteristics.

That is, as shown in FIG. 3, the tire reinforcing material is corrugated at an angle between the flat steel wire axis L and the wave ridgeline γ, so-called corrugation angle α of 90 °. The direction of corrugation and the direction of elongation of the reinforcing material match. Therefore, when a tensile load is applied to the reinforcing material for a tire, the characteristic that the wavy wavy shape tends to return to the original shape and the characteristic that the steel wire itself tends to elongate are mixed together, and the primary elastic limit (inflection) Point) easily exists at low load.

Therefore, when such a reinforcing material is used for the belt portion of the tire, when a load exceeding the primary elasticity limit is applied to the belt portion due to an uneven contact surface of the tire or a decrease in air pressure, the tire There was a risk that permanent deformation would occur in the reinforcing material, and the rubber and the reinforcing material would peel off, and sometimes the tire would be deformed.

The present invention has been made in view of the above problems, and has as its object to provide an inexpensive tire reinforcing material having good adhesion to rubber, flexibility, and elongation characteristics.

(Means for solving the problem) In order to achieve the above object, the tire reinforcing material of the present invention has a width d = 1.2t to 2.5t (thickness t = 0.2 to 0.7mm).
In the longitudinal direction of the flat steel wire having a flat cross section, meandering width D = 1.
A continuous snake with a meandering pitch P of 3 to 30 mm at 1d to 2.5d is provided, and the breaking elongation is 2.5 to 6%.

In the above configuration, the reason why the thickness t of the flat steel wire is set to 0.2 to 0.7 mm has a balance with the width d of the flat steel wire, but if it is smaller than 0.2 mm, the required strength cannot be obtained. If it is larger than mm, the flexibility in the thickness direction is inferior.

The reason why the width d of the flat steel wire is set to 1.2 to 2.5 times the thickness t is substantially the same as that described above, but if the width d is smaller than 1.2 times, the required strength cannot be obtained. If it is large, the flexibility in the width direction is inferior, and furthermore, the effect of elongation due to snaking is not remarkably exhibited.

Further, the meandering width D and the meandering pitch P are the most important factors in the elongation characteristics, and they are in a correlation. The meandering width D is set to 1.1 to 2.5 times the width d of the flat steel wire, depending on the meandering pitch P. However, if the meandering width D is smaller than 1.1 times, the required elongation cannot be obtained, and the meandering width D is larger than 2.5 times. This is because the primary elastic limit exists at a low load and causes various adverse effects. Further, the meandering pitch P is set to 3 to 30 mm because it is difficult to make the meandering pitch P smaller than 3 mm in manufacturing, and if it is larger than 30 mm, necessary elongation cannot be obtained.

The reinforcing material can be more effectively bonded to rubber by plating the surface of the reinforcing material with two or more alloys containing copper and zinc.

(Example) In FIG. 1, (1) is a reinforcing material for a tire according to the present invention. Pitch 10mm,
After applying a wave height of 0.6 mm, cold rolling is performed by rolling rolls installed vertically and a predetermined dimension (for example, thickness t = 0.25 mm, width d = 0.49 mm, meandering pitch P =
11 mm, meandering width D = 0.74 mm).

By the way, the corrugation applied to the strand having a round cross-section before the rolling may be simply flat or spiral.

In the above embodiment, a flat wave was obtained by passing a wire between the gears. The reinforcing material for a tire is formed from a round wire to have a substantially flat track shape in cross section, but may be processed from a flat wire to have a flat rectangular shape in cross section.

Next, samples shown in the table below were prepared in which the width d and meandering width D of the flat steel wire were changed, and a tensile test was carried out. The results shown in FIG. 2 were obtained. The thickness t and the meandering pitch of each sample are the same, and t = 0.25 m.
m, P = 11 mm.

As is apparent from FIG. 2, all of the products D, E, and F of the present invention have an inflection point under a high load, and the elongation at break is in the range of 2.5 to 6% suitable for this kind of reinforcing material. Is within.
On the other hand, Comparative Products A and B have low elongation at break and poor flexibility. In the comparative product C and the conventional product G, the inflection point exists at a low load, and there was a problem in elongation characteristics.

Although the surface of the reinforcing material is smooth, in order to further improve the adhesiveness with rubber, the surface may be knurled to provide irregularities, or may be provided with grooves by groove processing.

(Effects of the Invention) Since the present invention has the above-described configuration, the flexibility in the thickness direction and the width direction of the flat steel wire is improved, the elongation characteristics can be satisfied, and the adhesion to rubber is good, and fretting is performed. It produces excellent effects such as easy and inexpensive production without wear. Furthermore, since the rubber thickness of the tire can be reduced, it is effective for reducing the weight of the tire and for saving energy.

[Brief description of the drawings]

FIG. 1 (a) is a plan view of a tire reinforcing material according to the present invention, (b) is a side view of (a), and (c) is AA of (a).
FIG. 2 is a load-elongation curve diagram showing a comparison between the product of the present invention, a comparative product and a conventional product, FIG. 3 (a) is a side view of a conventional tire reinforcing material, (b) is a side view, (C) is a BB cross-sectional view. 1 ... tire reinforcing material, d ... width of flat steel wire, t ... thickness of flat steel wire, D ... meandering width, P ... meandering pitch.

Claims (1)

(57) [Scope of request for utility model registration] 1. A width d = 1.2t to 2.5t (thickness t = 0.2t)
In the longitudinal direction of the flat steel wire having a flat cross section of 0.7 mm), a continuous snake with a meandering width D of 1.1 d to 2.5 d and a meandering pitch P of 3 to 30 mm is provided, and the breaking elongation is 2.5 mm. ~ 6%
A reinforcing material for tires, characterized in that: