JPH04183612A - Hybrid bead for tire - Google Patents

Abstract

PURPOSE:To improve strength and adhesion to rubber and reduce the weight by providing a composite material layer consisting of high-strength low-extension fibers and thermosetting resins around a ring-shaped central core wire, and also by applying one layer of coat of plated steel wires around the outer circumference of the composite material layer. CONSTITUTION:A core wire 1 may be made of a wirelike composite material consisting of high-strength low-extension fibers and thermosetting resins, however, it is preferably made of steel wires. On the outer circumference of the core wire 1, a composite material layer 2 consisting of high-strength low- extension fibers and thermosetting resins is provided. Further, on the outer circumference of the composite material layer 2, a plurality of, usually 20 to 30, plated steel wires 3 are provided, and thereto one layer of adjacent steel wires 3a, 3b (not shown) are closely wound around so as to be in contact with each other. And on the outer circumference of the plated steel wires 3, a cover rubber 4 (not shown) is applied. Thereby, while securing a load-extension characteristic in the elastic region, the weight can be reduced. Further, the deterioration in the characteristic by the external damage caused by shear can be prevented, and also the adhesiveness to rubber can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hybrid bead used in tires for automobiles.

[Conventional technology and its technical issues]

As is well known, tires for trucks, buses, and passenger cars are composed of four parts: a tread, a carcass, a breaker, and a bead. Among these, the bead part prevents the deformation of the tire caused by the diamond filling air pressure and external force, and plays the role of stabilizing it on the rim.As a reinforcing material,
A ring-shaped hard steel wire is buried.

This bead reinforcing material is required to have good strength, good adhesion to rubber, and characteristics capable of withstanding deformation under high loads due to the above-mentioned purpose of use. For this reason, in the past, carbon content was generally 0.72 to 0.82% and wire diameter was 0°94 to 1.6%.
0++++a hard steel wire (bead wire) was used, which was blued to withstand high loads, and plated steel wire was used with bronze plating on the surface to ensure good adhesion to rubber. .

Conventionally, when obtaining a bead part, the bronze-plated steel wire is formed into a multilayer of 20 to 100 turns in an aligned state,
Before this molding, it was covered with insulation rubber, and after molding, depending on the type, it was covered with cover rubber and inserted into the tire.

Specifically, when the wire diameter is 0.94 to 0.97 mm,
Several pieces are flowed at the same time and the cross section is shaped into a square.
In the case of a wire diameter of 1.30 to 1.83+am, one wire was flown and the cross section was hexagonal (hexagonal bead). Also, wire diameter 1
．． Another type when using 30-1, 83m+n is a multi-layered spiral winding of bronze-plated steel wire around the wick wire.

There was one shaped into a circle (cable bead).

However, in such prior art beads, the reinforcing material is steel wire, and in a typical truck/bus tire, the bead weighs about 4.0 kg per tire. This increases the weight of the tire, increases fuel consumption, and poses problems from the standpoint of protecting the natural environment.

[Means to solve the problem]

The present invention was devised to solve the above-mentioned problems, and its purpose is to provide a material with good strength, good adhesion to rubber, and characteristics that can withstand deformation under high loads. The object of the present invention is to provide a hybrid bead that can achieve these features while also being significantly lighter in weight.

In order to achieve this objective, the present invention provides a composite material layer of high strength, low elongation fibers and thermosetting resin around a ring-shaped central core wire, and coats the outer periphery of this composite material layer with # It has a structure in which the l-line is coated in one layer.

[For production]

The bead of the present invention does not consist entirely of a linear composite material of high-strength, low-elongation fibers and thermosetting resin, but instead consists of high-strength, low-elongation fibers and thermosetting resin between the core wire and the outer plated steel wire. A linear composite material with a synthetic resin is wound in multiple layers. Therefore, although the load-elongation characteristics in the elastic region are maintained at the same level as those of conventional plated steel wires, the weight can be significantly reduced. Moreover, since the linear composite layer of high-strength, low-elongation fibers and thermosetting resin is covered with a plated steel wire on the outer periphery, the properties will not deteriorate due to shearing trauma, and the rubber Good adhesion can also be achieved.

The present invention will be explained below based on the accompanying drawings.

Figures 1 to 4 show hybrid beads according to the invention. Reference numeral 1 denotes a core wire, which may be a linear composite material of a high-strength, low-elongation fiber and a thermosetting resin, but is preferably made of a steel wire. Reference numeral 2 denotes a composite material layer of high strength, low elongation fibers and thermosetting resin provided around the outer periphery of the core wire 1. 3 is a plurality of plated steel wires (usually 20 to 30 pieces) that cover the outer periphery of the composite material layer 2, and the plated steel wires are adjacent steel wires 3a.

3b are tightly wound in a single layer so that they are in contact with each other.

4 is a cover rubber applied to the outer periphery of the layer-wound plated steel wire.

Specifically, as shown in FIG. 6, the composite material layer 2 is made of carbon fiber, silicon carbide fiber, polyaramid fiber, glass fiber,
Multifilament 20 made of high strength, low elongation fiber such as polyvinyl alcohol fiber, boron fiber, alumina fiber, etc., and thermosetting resin 2 such as epoxy resin, unsaturated polyester resin, polyimide resin, phenol resin, furan resin, etc.
It consists of a multi-layered and cured linear composite material 2a impregnated with 1. The plated steel wire 3 has a carbon content of 0 as well as known wires.
．． 72-0.82%, wire diameter 0.94-1, 60+am
The steel wire used is blued and bronze plated.

7 and 8 illustrate a method of manufacturing beads according to the invention. First, FIG. 7 shows the process of obtaining a linear composite material 2a. In this process, a multifilament 20 made of high strength, low elongation fiber is wound up, and the multifilament 20 is pulled out from a roller 200 and passed through a thermosetting resin in a resin tank 220 via a guide roller 210 to be impregnated with resin. , to form a prefreg 2a'. Then, this prefreg 2a' is introduced into the shaping die 240 via the guide roller 230, and the amount of impregnated thermosetting resin is 25 to 60V.
Remove excess thermosetting resin to approximately 1% o.
Thereafter, it is passed through a drying oven 250 and dried under conditions of, for example, 100° C. for 5 minutes to semi-cure the thermosetting resin, and then wound onto a reel 260.

Since the surface of the thermosetting resin of the linear composite material 2a is in a dry state, even if it is continuously wound on the reel 260, the linear composite material 2a
There is no such thing as 8 being glued together.

To obtain the bead of the present invention, as shown in FIG. 8(a), the ends of the core gA1 are abutted against each other in consideration of ease of assembly and joined by welding or the like to form a core wire ring 10 of a desired diameter. 11
is the joint. Next, as shown in FIG. 8(b), the linear composite material 2a is wound multiple times around the core ring 10 so as to have a required dimension d uniformly over the entire length. In this step, the linear composite material 2a may be wound one reel at a time, or the linear composite material 2a may be drawn out from multiple reels and wound simultaneously. At this time, since the thermosetting resin of the linear composite material 2a is in a semi-hardened state, it is highly flexible, and the core wire 1
It can be placed in close contact with the outer periphery of the

A composite material layer 2 is obtained in this step.

Next, as shown in FIG. 8(e), the plated steel wire 3 is attached to the composite material layer 2.
Wrap one layer on top of , and finish it to the required bead diameter d2.

In this process, the plated steel wire No. 3 is wound around the composite material layer 2 while shifting the phase every ±1 turn, and the winding direction is as follows:
The direction may be the same or opposite to that of the composite material layer 2. This results in the state shown in Figure 3. After that, a cover rubber 4 is wrapped around the outer periphery of the -layer-wound plated steel wire 3 to maintain its shape.

Finally, it is assembled into a tire together with, for example, a carcass material and a belt material, and is vulcanized. This vulcanization temperature is usually about 150° C. At this temperature, the semi-cured thermosetting resin is completely cured, and the strength of the composite is exhibited. Furthermore, the above temperature promotes the adhesive reaction between the plating surface and the rubber.

In addition, the material of the high strength and low elongation fiber, the type of thermosetting resin,
If the linear composite material 2a has sufficient flexibility pressure against bending due to the amount of impregnation, etc., or if the diameter of the core ring 10 is large, the linear composite material 2a will not be in a prepreg state and the thermosetting resin will be completely The core wire 1 may be wound in multiple layers in a hardened state, and this is also included in the present invention.

〔Effect of the invention〕

According to the present invention as described above, a composite material that has good adhesion to rubber, has strength and the characteristics of being able to withstand deformation under high loads, can realize significant weight reduction, and is weak against shearing force. The excellent effect of being able to provide a highly practical tire bead with its weak points compensated for can be obtained.

〔Example〕

■, core wire C: 0.72%, diameter (do): 2.5++m
Using this wire, the end faces were welded to obtain a ring with a diameter of 632a+m.

A linear composite material was wound around this ring in multiple layers to a thickness of 4.5 m+a. The linear composite material is carbon fiber 1200 with a diameter of 7 μm.
A multifilament with a total cross-sectional area of 0.46 mm2, which is made up of parallel filaments, is passed through molten epoxy resin and impregnated, and the impregnated amount is 37vo1% with a shaping die. The epoxy resin was treated at 100" CX for 5 minutes and the epoxy resin was in a semi-cured state. The diameter d1 at this stage was 11.5 mm.

Next, one layer of bronze-plated steel wire was wound around the outer periphery of the composite material layer. Bronze plated steel wire has C: 0.72%.

Wire diameters of 1 and 6 mm were used, and the number of turns was 24. The diameter d2 of the resulting bead was 14.7 square meters.

For comparison, a bead (conventional product) was obtained using a bronze-plated steel wire with a carbon content of 0.72%, a wire diameter of 1, and a wire diameter of 6+++ m, and the number of turns was 57.

■0 The weight of the inventive product and the conventional product is 1.
91 kg, and the product of the present invention weighs 1.18 kg, which is approximately 40 kg.
% weight reduction was achieved. In addition, FIG. 9 shows the results of a load-elongation test for the product of the present invention and the conventional product.

In Fig. 9, A is the load-elongation curve of the core wire + outer wire;
B is a load-elongation curve of a single carbon fiber composite material. The load-elongation characteristics in the elastic region (up to 0.9% strain) are almost the same for the product of the present invention and the conventional product.Moreover, the product of the present invention does not break until about 28 tf beyond the elastic range, and is resistant to impact loads. I can afford to resist. It is clear that this is the effect of the combination of high-strength, high-elasticity composite materials.

In order to examine the adhesion to rubber, a bead embedded in rubber was vulcanized and the rubber was peeled off, and the results showed that the product of the present invention and the conventional product were equivalent.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a hybrid bead according to the present invention, FIG. 2 is a sectional view taken along line nn in FIG. 1, and FIG. 3 is a sectional view taken along line nn in FIG. Figure 4 is the first
5 is a partially enlarged view of FIG. 1, FIG. 6 is a sectional view of the linear composite material of the present invention, and FIG.
FIG. 8 is an explanatory diagram showing the process of manufacturing a linear composite material, FIG. 8 is an explanatory diagram showing the process of obtaining a bead of the present invention, and FIG. 9 is a load-elongation diagram of the present invention and a conventional product. 1... Core wire, 2... Composite material layer, 2a... Linear composite material, 3... Plated steel wire, 4... Cover rubber, 20...
High strength, low elongation fiber, 21...Thermosetting resin

Claims (2)

[Claims] (1) A composite material layer of high-strength, low-elongation fibers and thermosetting resin is provided around the ring-shaped center core wire, and the outer periphery of this composite material layer is coated with a layer of plated steel wire. Hybrid bead for tires. (2) The hybrid bead for tires according to claim 1, wherein the composite material layer is formed by multiple windings of semi-cured thermosetting resin prepreg and is completely cured during rubber vulcanization.