JPH1095207A - Pneumatic radial tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise of the outside of a car and road noise by alternately arranging carcass ply cords every one cord or every two cords so that the heat contraction ratios may be different from each other, concerning a radial tire provided with a carcass ply layer formed by rubber-coating organic fiber cords provided with the specified total denier. SOLUTION: An organic fiber cord having the total denier in the range of 1,000 to 6,000 is used as an organic fiber cord to be used for a carcass ply in a pneumatic radial tire for a passenger car, the cords of the carcass ply are alternately arranged every one cord or every two cords so that the heat contraction ratios measured based on JIS-L1017 may be different from each other. The difference between the heat contraction ratios is set to the range of 0.5 to 2.0 by changing the number of twisting of the cords or using plural kinds of cords having the heat contraction ratio different from each other. Therefore, tensile load of the carcass ply cords is changed in a tire, the vibration damping effect of the carcass ply is dispersed, and noise of a tire and road noise are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic radial tire for a passenger car using a specific carcass ply.

[0002]

2. Description of the Related Art At present, car cords of radial tires for passenger cars use tire cords of the same standard in the same tire. Using the same code like this,
The uniformity of the tire is good because of its excellent uniformity, but the damping effect of the carcass ply is limited to a certain area.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to change the tension load of a carcass ply cord when a tire is formed, disperse the damping effect of the carcass ply, and as a result, reduce tire noise and road noise. It is to make it.

[0004]

In order to solve the problem that the damping effect of the carcass ply of the tire is limited to a certain area, the present inventor has set a code used for the carcass ply as one. A cord having a different heat shrinkage was used alternately every two or every two cords. as a result,
Surprisingly, by changing this cord arrangement, the tension load of the carcass ply cord of the tire is changed,
It became clear that the vibration damping effect of the carcass ply cord was dispersed, and as a result, tire noise and road noise were reduced. At this time, if the cords having different thermal contractions are used, the uniformity of the tire, that is, the uniformity may be deteriorated. However, the uniformity is deteriorated by alternately arranging every other wire or every other wire in the same carcass ply. It was also found that can be suppressed.

That is, in the present invention, the total denier is 1,
In a radial tire having at least one or more carcass ply layers in which 000 to 6,000 organic fiber cords were covered with rubber, the carcass ply cords were measured every other or every other cord in accordance with JIS L1017. A pneumatic radial tire using a carcass ply that is arranged alternately so as to have different heat shrinkage ratios and that has a difference in heat shrinkage ratio of 0.5% or more and 2.0% or less. JI
According to S standard L1017, the heat shrinkage is measured at 175 ° ± 3 ° C. for 30 minutes.

The difference in heat shrinkage is 0.5% or more and 2.0%
If it is below, deterioration of uniformity can be suppressed, and good noise and road noise can be reduced. If the difference in heat shrinkage is less than 0.5%, good noise and road noise cannot be reduced, and if the difference in heat shrinkage exceeds 2.0%, uniformity will be deteriorated.

The organic fiber cord used for the carcass ply has a total denier of 1,000 to 6,000.
Within this range, the strength as a tire for a passenger car can be maintained appropriately and the tire can be kept lightweight. If it is less than 1,000 denier, the carcass ply layer must be excessively increased, resulting in an increase in weight. On the other hand, if it exceeds 6,000 denier, the number of shots required to achieve the strength required for the tire is extremely small, so that the gauge between the cords is too wide, which causes a failure due to separation.

The difference in the heat shrinkage can be set arbitrarily by changing the number of twists with the same cord or using a cord of a different heat shrinkage.

It is effective to reduce the noise and the road noise when the cords are alternately arranged every other or every two cords. However, when the cords are alternately arranged every three or more cords, the effect of reducing the noise and the road noise is reduced. Becomes thinner. In FIG.
The carcass ply of the present invention is shown in a cross section cut at a right angle to the main fiber direction of the sump. The C type is alternately arranged every other fiber, the D type is alternately arranged one and two, such as A1-B2-A1-B2-... and the F type is every two fibers They are arranged alternately.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. (Example) In this example, the tire size is 205 / 65R15.
Was used. As the main fiber cord of the carcass ply, polyethylene terephthalate (PET) fiber, rayon, and nylon were used. The code arrangement E of the comparative example is A, B, B,
The case of arrangement of B, A, B, B, B ... is shown. Code A,
Code B corresponds to A and B in FIG. The tire has a tubeless structure, the belt layer is a two-layered structure using steel cord, the belt reinforcing layer is 90 ° one layer using nylon fiber, the carcass ply layer is one, and only two sheets are used for Comparative Example 2. Was.

[0011] The measurement of outside noise is carried out according to the automotive standard JASO.
The test was carried out in accordance with the vehicle exterior noise test method specified in Z101-83, the vehicle was driven at a speed of 60 km / h, the overall noise was measured, and the noise reduction (dBA) was displayed based on the conventional example. .

The road noise indicates the amount of reduction (dBA) of the entire noise on a rough asphalt road at a speed of 50 km / h based on the conventional example.

[0013] The drum durability performance is 15 times the JATMA load.
Add 0%, drive at 60km / h, 10,000km
In the case of failure in the following running, it was NG.

The results are shown in Table 1.

[Table 1]

In Comparative Example 1, the difference in heat shrinkage between cord A and cord B was thought to be due to exceeding 2.5 and 2, but the uniformity was NG. In Comparative Example 2, code B
Is 500 d / 1, which is 1000 denier or less, and the carcass ply layer needs to be excessively increased, which causes an increase in tire weight. In Comparative Example 3, since the code B is 4000d / 2, it is 6000D or more. As a result, the difference between the stress applied to the cord and the rubber at the end of the ply is increased, and separation is easily caused.
Therefore, durability decreases.

In Comparative Example 4, the effect of reducing both vehicle exterior noise and road noise is small, probably because the code arrangement type is E. In Comparative Example 5, the difference in the thermal shrinkage between the cord A and the cord B was 3, which is considered to be caused by exceeding 2, but the uniformity was NG.

[0017]

The pneumatic radial tire for a passenger car using the carcass ply of the present invention provides an excellent tire with less external noise and road noise to the market without impairing the uniformity of the tire, that is, uniformity and tire durability. Can be supplied.

[Brief description of the drawings]

The C, D, and F types in FIG. 1 show examples of the present invention in which carcass ply cords are arranged every other or every other cord so that the heat shrinkage measured according to JIS standard L1017 is different. It is a figure which shows the comparative example arrange | positioned in book 1, book 3, book 3.

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[Procedure amendment]

[Submission date] December 2, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 shows examples of the present invention in which carcass ply cords are arranged alternately or every other cord so that the carcass ply cords have different heat shrinkage rates measured according to JIS standard L1017. It is a figure which shows the comparative example arrange | positioned in three-one, three-three.

Claims (1)

[Claims] 1. A total denier of 1,000 to 6.0.
In a radial tire having at least one or more carcass ply layers obtained by coating an organic fiber cord of rubber with rubber, the cord of the carcass ply is provided every other or every two cords,
The heat shrink rates measured according to JIS standard L1017 are alternately arranged so as to be different, and the difference in the heat shrink rates is 0.5
A pneumatic radial tire using a carcass ply of not less than 2.0% and not more than 2.0%.