JPS5938103A - Radial tire - Google Patents

Abstract

PURPOSE:To improve durability, by preparing a synthetic-fiber filament coated with an organic high-molecular substance and by winding steel filaments around the single synthetic-fiber filament to define free spaces between the steel filaments, and providing reinforcing synthetic-fiber thread layers of prescribed tensile modulus at both the side edges of a breaker layer. CONSTITUTION:A single synthetic-fiber filament 6a of polyester or the like is coated with a layer 6b of an organic high-molecular substance such as natural rubber so that a core 6 is provided. At least three, for example, four steel filaments 7 are wound around the core 6 so that free spaces 8 are defined between the steel filaments. A steel cord is thus provided for a breaker layer 11. A reinforcing thread layer 12 made of such a synthetic-fiber thread of 250 to 5,000kg/ mm.<2> in tensile modulus as a nylon thread is provided outside each of both side edges of the breaker layer 11. As a result, the ends of the steel cord are prevented from being separated from rubber and the comfortableness of riding is improved.

Description

[Detailed description of the invention] This invention relates to a radial tire.

In recent years, automobiles have become faster due to improvements in automobile performance and the expansion of highway networks, and steel cords have been widely used for tire breakers as automobile tires that can withstand high speeds. Conventionally, the steel cord I used in the single layer of the breaker was generally made by compactly twisting strands of 4 to 6 steel wires. For example, the steel cord in Figure 1 is made by twisting four strands 1, and the steel cord in Figure 2 is made by twisting six side strands 3 around a core strand 2 of one tree. It is something that As shown in FIGS. 1 and 2 above, a steel cord in which strands of wire are twisted closely together has a sealed void 4 or 5 formed therein. If such a steel cord is buried in one layer of rubber in the player, rubber will not fill the above-mentioned closely spaced gap 4.5, so if the tread of the radial tire is damaged due to external injury, water will leak out from the damaged area. If the water penetrates into the steel cord, the water spreads through the voids in the steel coat, causing rust on the steel cord, and this rust makes it easy for the layers of the breaker to separate. In addition, since the wires are in close contact with each other, the wires wear out due to friction between the wires, the so-called fretting phenomenon.
Fatigue resistance decreases. Furthermore, since the wires are compact and close together, the outside diameter of the steel cord is less than the rri law, and the tread of the tire cannot be sufficiently covered by the steel cord, so a nail inserted into the tire is obstructed by the steel cord. In some cases, they could penetrate deep into the air without causing damage to the tires.

In order to eliminate the above-mentioned drawbacks, the applicant previously
As shown in FIG. 3, we have proposed a steel cord for automobile tires in which at least three side strands 7 are arranged around the outer periphery of one core strand 6 so as to have a free space 8 between them. (See Publication No. 56-31090). However, in the steel cord proposed above, when the side strands are wound around the outer periphery of the core strand and twisted together, the lateral strands tend to slip and become misaligned, resulting in partial unevenness in the twist pitch. Also, even if the cross-sectional structure is normal when twisted to steel cords, during tire manufacturing processes such as topping, cutting, molding, and vulcanization, as shown in Figure 4, the rubber G It has been found that there is a problem in that the cross-sectional shape is distorted, the free space 8 between the side strands 7 and 7 disappears, and a closed gap 9 is formed, which causes rust to develop and cause peeling and tire damage due to fatigue. Especially carbon content 0.7
Consisting of 5-0.85% by weight of steel filaments,
The steel cord is expressed as the formula% (in the above formula, the diameter of the Dfl steel filament + 111
11゜N is the number of steel filaments, W is the weight per meter of steel cord f, TS is the tensile strength kq, and the denominator 7.86 indicates the specific gravity of iron. When using steel cord,
Cord toughness may deteriorate.

In addition, an organic fiber is used as a core wire, and 3
A steel cord (International Publication No. WO 30/2572) in which ~5 side strands are wound so as to have free space between them is known, but this steel cord also has the same slenderness as described above.

Furthermore, a reinforcing layer steel cord (see Japanese Utility Model Application Publication No. 70804/1983) is known, which is made by twisting together a plurality of steel filament single wires coated with rubber in advance. As shown in Figure 2, there is no free space in the side strands,
Furthermore, since all of the side strands and the core strands are coated with rubber, there is a problem in that the friction between the strands increases, making it difficult to position each strand when twisting together.

On the other hand, when a car/vehicle runs at high speed, the outer periphery of the tire expands due to the centrifugal force generated by the high-speed rotation of the tire.However, since the expansion is large at both widthwise ends of the breaker layer, stress concentration occurs at the ends of the Nutille cord. There is a problem in that this causes peeling between the rubber part and the rubber part, and that the riding comfort is poor.

In order to solve the above problems, this invention uses one synthetic fiber filament as a core wire, provides a coating layer made of an organic polymer only on this core wire, and also provides a coating layer made of an organic polymer material on the outer periphery of both ends of a single layer of a breaker. A reinforcing yarn layer made of fiber filament yarn is arranged in the circumferential direction of the tire.

In other words, this invention uses a single synthetic fiber filament in which the breaker layer has a steel layer as a core steel wire! and at least three wooden steel filaments are wound around the outer periphery of the core element wire so as to have free space between them,
The present invention is a radial tire characterized in that reinforcing yarn layers made of synthetic fiber filament yarns having a tensile modulus of 250 to 5000 kQ/rtlt are arranged in the tire circumferential direction on the outer periphery of both ends of the single layer of the player.

An example of the steel cord according to the present invention will be explained with reference to FIG. 5.
A coating layer 6'b made of an organic polymer material is formed on the outer periphery of the core wire 6, and steel filaments l~
The four side wires 7 consisting of
A free space 8 is formed between them.

Further, an example of the radial tire according to the present invention will be explained with reference to FIG. A breaker layer consisting of two plies in which steel cords are arranged so as to intersect each other at an angle of 15 to 30 degrees with respect to the center line C at the outer periphery of the central part of the breaker layer 12, and both ends of the breaker layer 11 in the width direction. This reinforcing thread layer 12 is a reinforcing thread layer provided on the outer periphery of the tire, and this reinforcing thread layer 12 is made by winding synthetic fiber filament threads 12a in the circumferential direction of the tire.

The synthetic fiber filament 6a forming the core wire 6 is a monofilament made of polyester, nylon, vinylon, aromatic polyamide, or the like.

The organic polymer material forming the coating layer 6b of the core wire 6 is a topping rubber made of natural rubber or synthetic rubber, or a resorcinol formaldehyde resin adhesive.

The covering layer 6b is formed by immersing a synthetic fiber filament in a solution or melt of the organic polymer substance, pulling it up, and then drying or cooling it. The thickness of the coating layer is preferably 0.01 to 0.07 mm, and the thickness is 0.0 mm.
If the thickness is less than 1 mm, the coating layer will easily peel off during the twisting process of the steel cord, and if the thickness exceeds 0.07 mm, the coating layer will stick to rollers etc. during the twisting process, resulting in a large amount of damage when pulling out the twisted steel cord. The cutting process requires a lot of force, and the topped cord blinds warp.
The efficiency of the tire building process may be reduced.

In the example shown in FIG. 5 above, the synthetic fiber filament and the steel filament are shown to have the same thickness, but the thicknesses of both filaments do not have to be the same.

The number of side strands is at least 3, and the side strand is 1 *
If there are two straddled steel cords, the shape of the steel cord will become unstable. If the thickness of the core wire and side wire are the same,
The number of side strands is 3 to 5, and when there are 6 side strands, the side strands are crossed as shown in FIG. 2, and no free space is formed between the lateral strands. When the core wire is thicker than the side wires, a free space can be formed even if the number of side wires is six or more.

The free space G formed between the side strands is calculated using the following formula: G =
((1+D)Sin −-ri, N In the above formula, d is the diameter ytnl of the core wire including the coating layer, D is the diameter ynm of the side wire, and N is the number of side wires. The above free space Gu□ , 03 or more is preferable.

The synthetic fiber filament yarn 12a forming the reinforcing yarn layer 12 of this invention has a tensile modulus of 250 to 5000/c.
q/-, and if it is less than 250 klj/-, the effect of suppressing the deformation of both ends of the platter cannot be obtained;
If it exceeds 000 kQ/-, peeling occurs between the reinforcing yarn and the rubber layer, and fatigue fracture is likely to occur, which is not preferable.

As this synthetic fiber filament yarn, nylon, aromatic polyamide (trade name: Kevlar), etc. are preferable, and these filament yarns may be twisted yarns and have a thickness of 0.
．． A range of 25 to 1, QIIFIII is preferable. This reinforcing yarn layer may use the filament yarn as a weave. The reinforcing thread layer is used by being pre-immersed in the above-mentioned topping rubber covered resorcinol formaldehyde resin adhesive and then dried. The reinforcing yarn layer is arranged such that its filament yarns are arranged in parallel in the tire circumferential direction, but may be arranged at an angle of 1 Off or less with respect to the tire circumferential direction. The reinforcing yarn layer is provided so as to completely cover the end portion of the player layer, as shown in FIG. 6 above. In this invention, even if one layer of the breaker is damaged by a nail or the like, water will not enter the steel cord from the damaged part and the steel cord will not rust and disappear. It is not necessary to cover the entire width.Also, it is possible to use steel filaments as a reinforcing yarn layer, but in this case, the weight of the tire increases, so it is not necessary.

This invention will be explained in detail below.

Example (1) As a steel cord core wire, a nylon seven filament (440 denier 1. diameter 0.235 cm) was coated with a thickness of 0.03 f on the outer periphery.
A material having a coating layer made of topping rubber with a coating weight of 10% by weight was used. Side wire and T, Te, 5W1)
<S 82A 'E fc ld 5WFrS 72A
A steel wire with a diameter of 0.25 mm and a 17 mm ratio of 63 parts copper and 370 parts zinc was used. A steel cord having the cross-sectional shape shown in FIG. 5 was manufactured by twisting one core wire of JIJ and four core wires at a cord twisting pitch of lOrttm. For comparison, a steel cord shown in FIG. 3 without a coating layer on the core strand and a steel cord shown in FIG. 1 without a core strand were constructed. The performance of these steel cords is shown in Table 1 below. (Hereinafter, blank space) Table 1 The impact resistance in Table 1 is expressed as a ratio when the shear impact energy of each cord is measured and the code symbol is E'k 100. The shear impact energy is sample 9, 5 cm
A part of the hammer had a blade with a cutting edge curvature of 0.45WIn at an angle of 60 degrees, using a Charpy type impact tester in the center of the
The measured value was calculated using the following formula, assuming that the arm length was 50 cm and the hammer weight was 800 g.

In the above formula, W is the hammer weight (k!7), L is the arm length (cm), θ is the arm swing angle after the test specimen is broken,
6° is the arm swing angle when no sample is attached, 4 is the sample length (cm), and S is the sample cross-sectional area (CJ).

1. The calculated value in the free space is the calculated value CG according to the above formula.
), and rewinding E+J, the latter value is the steel cord being passed from one reel to 5 pulleys (diameter 5 Q t
The operation of passing the steel cord through the wires in a zigzag shape bent at right angles and winding it on the other reel is repeated 20 times, and the steel cord before and after winding is embedded in acrylic resin to create a free space between the side wires. This shows the maximum value measured in space using a microscope micrometer. The fact that the free space changes significantly after unwinding mJ indicates that the side strands are displaced and the steel cord loses its shape; It represents something big.

(2) Tire The above-mentioned steel cord is made into a platy layer, a polyester cord (1500 (IX2)?e-carcass layer is made,
Nylon thread (840d
A 1653R1B automotive radial tire was manufactured, which was provided with a reinforcing yarn layer (width Iff) consisting of x2, tensile modulus y, 52 okq/m4. The number of ends in one layer of the above breaker is 20 if the side wire is 5WSR82A cord.
strands/2.54m, 5WSR72A:+l'f) is 23 strands/2.541, the cord angle is 20 degrees, the number of strands per strand is 2, and the number of ends of the reinforcing yarn layer is 13. /2.54c1n, the number of sheets is 1,
It is treated with a resorcinol-formaldehyde resin adhesive.

The rubber composition used to manufacture the tire is as shown below, and the iron layer of the core wire? This rubber composition was also used for the covering layer, topping rubber, and reinforcing thread layer.

Natural rubber 100 parts HAF
55ZnO7 Stearic acid 2 Trimethyldihydroquinoline polymer 2Sin, B Resorcinol 25 Melamine derivative 2.5 Cobalt naphthenate 2.5 Sulfur
4 Cyclohexylbenzthiazylsulfenamide 0.8 (31) Tire Performance Test The tire performance test is shown in Table 2 below.

(Left below) Table 2 The drum high speed durability in the table above is based on air pressure of 2.1...kg.
/cd, the tire is drum rotated with 100% load, 120
After rotating for 30 minutes at 1 km/h, the speed was increased at a rate of 10 x 1/hr every 30 minutes to show the degree of tire failure.

In the salt damage drum test, the diameter from the inside of the tire to the layer of flakes was 3II! Drill 8 holes of size 11 at regular intervals around the tire circumference, inject 500cc of 5% saline solution into the hollow part of the tire, and apply a load of JI3100%.
Tire pressure 1.7 kglct & drum running speed 4
A drum rotation test was conducted at 0km/1 o'clock. The one of the present invention had a mileage @ 17,000/l: No tire damage was observed up to the shoulder, but the comparative example had a mileage of III 2,100/l.
The tire broke after 1.5 km, and the cause was rust on the steel cord.

In the salt damage test test, eight 3mm diameter drill holes are drilled at equal intervals around the circumference of the tire between the outer side of the tire and the breaker layer, and a car with the tire is mounted on each of the four axles. 5000 at a speed of 80 b/hr on a test course with a 1 oyn long salt water pool (5% saline solution)
The tire was run at a speed of 1 km, and then the area of rust generated on the single breaker layer of the tire was expressed as a percentage of the total area of the breaker layer. In the figure-8 turning test, a figure-8 turning course consisting of two connected circular courses with a radius of 30 nt was tested under a load of JIS 1.
00%, tire pressure is 1.7 kg/afi, drive at 25 km/h, remove the tire every 100 turns, and take an X-ray photo of the broken steel cord of the breaker layer to determine if the cord is broken. It is indicated by the number of turns when this occurs.

The 50,000 km peel test is performed after the tire has been driven for 50,000 km.
Peel off the space between the two breaker layers with a knife, measure the area of the peeled part of the cord at the side edge part (edge part) of the breaker layer and the breaker layer body, and determine the tire T2'k1.
The area ratio of each tire is shown below.

Breaker - Air permeation amount is determined by extracting a steel cord from a molded tire, inserting one steel cord cut into 3 cm length into the center of a rubber compound block of length 6Cn11 width 2.5α and thickness 2.5 cm. pressure 3
Vulcanize at 0 kq/cl, then grind both ends of this vulcanized block in the vertical direction with a grinder to a length of 5 C1n, then pressurize compressed air at a pressure of 5 kq/crA into one end of the block to form rubber. This is the amount of air flowing out from the other end of the block, measured using a flow meter.

As explained above, in the radial tire of the present invention, the steel cords have free space with each other even after the tire is molded, and even in the salt damage test and the figure 8 turning test, the cord breakage of the tire is reduced and the durability is improved. improve,
Moreover, peeling during running at 50,000 krn has been significantly reduced.

[Brief explanation of the drawing]

1M and 2 are cross-sectional views of conventional steel cords in which strands are twisted closely together, FIG. 3 is a cross-sectional view of the steel cord that is the premise of this invention, and FIG. 5 is a cross-sectional view of an example of the steel cord according to the present invention, and FIG. 6 is a partial cross-sectional view of the radial tire according to the present invention. 6: core strand, 6a: covering layer, 7: side strand, 8: free space, 11: single breaker layer, 12: reinforcing yarn layer. Patent applicant: Toyo Rubber Industries Co., Ltd. Representative Patent attorney: Takeo Sakano 〃〃 Yoshi 1) Tsukasa Ryo Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) A radial tire in which one layer of the breaker is made of a steel cord, the steel cord has a core wire of one synthetic fiber filament having a coating layer made of an organic polymer substance on the outer surface, and the core wire At least three wooden steel filaments are wound around the outer periphery of the plater so as to have free space between each other, and a tensile modulus of 250 to 5000 kti/
- A radial tire characterized in that a reinforcing yarn layer made of synthetic fiber filament yarn is arranged in the circumferential direction of the tire. It is a type adhesive whose thickness is (101~o, ortmt
A radial tire according to claim 1. [3] The radial tire according to claim 1 or 2, wherein the synthetic fiber filament forming the core wire is a nylon monofilament. [4] A radial tire according to any one of claims 1 to 3, wherein the number of side strands is 3 to 5. [5] Steel filament forming the side wire. The carbon content is 0.75-0.85%, and the steel cord is expressed as % (in the above formula, D is the diameter my of the steel filament, N is the number of steel filaments, and W is the steel cord 1 m).
Per unit weight da, TSi-j tensile strength kQVcL. 5. The radial tire according to claim 1, wherein the radial tire has a tensile strength calculated as follows: 7.86 in the denominator indicates the specific gravity of iron. [6] The radial tire according to any one of claims 1 to 5, wherein the synthetic fiber filament yarn forming the reinforcing yarn layer is a nylon filament yarn.