JP2003063210A - Pneumatic radial tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce deterioration of passing noise and rolling resistance to be within a minimum permissible limit, effectively exerting a reducing effect of road noise. SOLUTION: When sectional area per band cord is taken S (unit; mm<2> ), modulus at the time of elongation 2% is taken M (unit; N/mm<2> ), and arrangement density of band cord per width 1 cm of full band ply 9A is taken D (unit; number/cm) in the full band ply 9A and edge band ply 9 made by spirally winding strip ply 13, elongation drag value K fixed by the following expression is set up as 110 to 386. K=S×M×D/100...(1).

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 capable of reducing road noise while minimizing deterioration of passing noise and rolling resistance.

[0002]

2. Description of the Related Art In a pneumatic radial tire, in order to improve high-speed durability,
A band layer made of a band ply in which a band cord is spirally wound is provided on the outside of the belt layer. It has been found that the provision of such a band layer reduces road noise (in-vehicle noise) near a frequency of 250 Hz. Particularly, by increasing the modulus of the band cord, the road noise reducing effect can be further enhanced. I've also come to understand.

On the other hand, as this band ply, a full band ply which covers substantially the entire width of the belt layer and an edge band ply which is separated at the center and covers both end portions of the belt layer are known, and in recent years, these are used together. The existing band layer is being adopted for high performance tires.

However, when a high modulus band cord is used for this band ply, although road noise is reduced, both passing noise (outside vehicle noise) heard outside the vehicle compartment and rolling resistance may be deteriorated. found. In this way, in the conventional pneumatic radial tire,
When a road layer is used to reduce road noise, passing noise and rolling resistance may be deteriorated.

Therefore, the present inventor has conducted various experiments on road noise, passing noise, and rolling resistance. Surprisingly, the extension drag value K of the band ply determined by the following equation (1) is obtained.
It has been found that by regulating the value of P to a certain range, it is possible to obtain an effect of reducing road noise while minimizing deterioration of passing noise and rolling resistance. K = S × M × D / 100 (1) In the formula, S is a cross-sectional area per one band cord (mm ² ),
M is a modulus (N / mm ² ) at an elongation of 2% per band cord, and D is a band cord array density (lines / cm) per 1 cm of ply width.

As described above, the present invention is based on the fact that the elongation resistance value K of the band ply is limited to a certain range found as a result of the experiment, and the deterioration of the passing noise and the rolling resistance is the minimum allowable limit. It is an object of the present invention to provide a pneumatic radial tire that can effectively exhibit a road noise reducing effect while being kept inside.

[0007]

According to a first aspect of the present invention, there is provided a belt layer disposed inside a tread portion and outside in a radial direction of a carcass, and a belt layer disposed outside in a radial direction of the belt layer. A pneumatic radial tire having a band layer composed of one full band ply covering substantially the entire width of a belt layer, wherein the full band ply is a single band cord or a plurality of band cords aligned. The full band ply is formed by spirally winding a tape-shaped band-shaped ply in which the body is embedded in a topping rubber, and the full band ply has a cross-sectional area of one S (unit: mm ² ) of the band cord, band cord modulus of M in elongation of 2% when the (unit: N / mm ^2), the arrangement density of the band cord per width 1cm full band ply D: Taki and (unit present / cm), the following Elongation drag value K (unit determined by: N
・ The pneumatic radial tire is characterized in that the number of lines / cm is set to 110 to 386. K = S × M × D / 100 (1)

[0008] The invention according to claim 2 further comprises a pneumatic layer comprising a belt layer disposed inside the tread portion and radially outside the carcass, and a band layer disposed radially outside the belt layer. In the radial tire, the band layer is composed of one full band ply covering substantially the entire width of the belt layer, and edge band plies on both sides of the belt layer which are arranged at both ends and outside thereof. The full band ply and the edge band ply are formed by spirally winding a tape-shaped band-shaped ply in which one band cord or an aligned body of a plurality of band cords is embedded in a topping rubber. The ply has a cross-sectional area of one of the band cords as S (unit: m
m ² ), the modulus of the band cord at 2% elongation is M (unit: N / mm ² ), and the band cord array density per 1 cm of the band ply width is D (unit: book / cm), Elongation drag value K determined by the following formula (unit: N ・ piece / c
m) is 110 to 386, which is a pneumatic radial tire. K = S × M × D / 100 (1)

The invention according to claim 3 is the ratio of the elongation resistance value K (unit: N · pieces / cm) of the edge band ply and the width WA of the edge band ply to the width WB of the belt layer. In the width ratio (WA / WB), when the elongation resistance value K is 110 or more and 170 or less, the width ratio (WA / WB) is set to be greater than 0 and 0.5 or less,
Moreover, when the elongation resistance value K is larger than 170 and 280 or less, the width ratio (WA / WB) is set to be larger than 0 and 0.07 or less, or 0.47 or more and 0.5 or less.
And the elongation resistance value K is larger than 280 and 386 or less, the width ratio (WA / WB) is 0.4.
3. The value is 7 or more and 0.5 or less.
It is the pneumatic radial tire described.

The invention according to claim 4 is the ratio of the elongation resistance value K (unit: N · pieces / cm) of the edge band ply and the width WA of the edge band ply to the width WB of the belt layer. In the width ratio (WA / WB), when the elongation resistance value K is 110 or more and 280 or less, the width ratio (WA / WB) is set to be larger than 0 and 0.5 or less,
Moreover, when the elongation drag value K is greater than 280 and less than 340, the width ratio (WA / WB) is greater than 0 and 0.4 or less, and the elongation drag value K is 340 or more and 386 or less. In this case, the pneumatic radial tire according to claim 2, wherein the width ratio (WA / WB) is greater than 0 and less than 0.28.

The invention according to claim 5 is the ratio of the elongation resistance value K (unit: N · pieces / cm) of the edge band ply and the width WA of the edge band ply to the width WB of the belt layer. In the width ratio (WA / WB), when the elongation resistance value K is 110 or more and 170 or less, the width ratio (WA / WB) is set to be greater than 0 and 0.5 or less,
Moreover, when the elongation resistance value K is larger than 170 and 280 or less, the width ratio (WA / WB) is set to be larger than 0 and 0.07 or less, or 0.47 or more and 0.50 or more.
The pneumatic radial tire according to claim 2, wherein:

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a meridional sectional view of the pneumatic radial tire of this embodiment. In the figure,
The pneumatic radial tire 1 (hereinafter referred to as tire 1) is
Bead part 4 from tread part 2 to sidewall part 3
A carcass 6 reaching the bead core 5, a belt layer 7 arranged inside the tread portion 2 and outside in the radial direction of the carcass 6, and a band layer 9 arranged outside in the radial direction of the belt layer 7. I am.

The carcass 6 is composed of at least one carcass ply 6A in which carcass cords are arranged at an angle of, for example, 75 ° to 90 ° with respect to the tire equator C, and in this example, one carcass ply 6A. The carcass ply 6A has a structure in which the bead cores 5 are attached to both ends of the main body 6a extending between the bead cores 5 and 5.
A bead apex for reinforcing a bead portion, which has a folded-back portion 6b that is folded back from the inner side to the outer side around the circumference, and extends between the main body portion 6a and the folded-back portion 6b in a taper shape from the bead core 5 to the outer side in the tire radial direction. The rubber 8 is arranged. As the carcass cord, a polyester cord is used in this example, but in addition to this, an organic fiber cord such as nylon, rayon, or aramid, or a steel cord if necessary can be used.

The belt layer 7 includes two or more belt cords arranged at an angle of, for example, 15 to 45 ° with respect to the tire equator C. In this example, two belt plies 7A and 7B are crossed with each other. It is constructed by stacking in the direction of doing. The ply width of the belt ply 7A on the radially inner side is wider than that of the belt ply 7B on the outer side, so that the ply width forms the width WB of the belt layer 7. In this example, a steel cord is used as the belt cord, but polyethylene naphthalate (PE
High modulus organic fiber cords such as N), polyethylene terephthalate (PET), and aromatic polyamide can also be used if necessary.

In the present embodiment, the band layer 9 includes one full band ply 9A that covers substantially the entire width of the belt layer 7 and edge band plies on both sides of the belt layer 7 on both ends and outside thereof. 9B and 9B are shown as an example. Here, with respect to the full band ply 9A, “covering substantially the entire width” of the belt layer 7 means the width BW of the belt layer 7.
This means that the width W of the full band ply 9A is substantially equal to the width WB of the belt layer 7 in this example. In this embodiment, the full band ply 9A is arranged on the inner side in the tire radial direction, and the edge band ply 9B is arranged on the outer side in the tire radial direction. However, the same effect can be obtained by stacking the band plies 9A and 9B in reverse.

Further, the full band ply 9A and the edge band ply 9B (hereinafter sometimes simply referred to as "band ply 9A, 9B" when collectively referred to) are composed of one band cord 11 or as shown in FIG. (In this example) The topping rubber 1 is made by aligning a plurality of band cords 11.
It is formed by spirally winding a tape-shaped strip-shaped ply 13 embedded in 2 in the tire circumferential direction, and the angle formed by the band cord 11 and the tire circumferential direction is set to 5 degrees or less. Since the band plies 9A and 9B formed by spirally winding the band-shaped ply 13 have a so-called jointless structure without a seam, they are excellent in the uniformity of the tire and help to firmly and surely restrain the belt layer 7. . In this example, for example, about 10 band cords 11 are aligned and buried, and the width W1 is, for example, 10 m.
An example using a strip-shaped ply 13 of about m is illustrated.

When the strip-shaped plies 13 are spirally wound on the outer side of the belt layer 7, as shown in FIG. 3 (A), it is preferable from the viewpoint of uniformity that the side edges of the adjacent strip-shaped plies 13 are in contact with each other. However, as shown in FIG.
Various winding methods can be adopted, such as one in which the side edges of the band-shaped ply 13 are wound apart from each other, or one in which the side edges of the band-shaped ply 13 are overlapped and wound as shown in FIG. 3 (C). Although the full band ply 9A has been described as an example in FIG. 3, the edge band ply 9B can be similarly wound by various methods.

As the band cord 11, in order to obtain a high road noise reduction effect, for example, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), aromatic polyamide, polyparaphenylene benzobisoxazole (PBO), or the like is used. Modulus of organic fiber cord, more specifically 2% modulus is 100
It is desirable to use a material of 00 (N / mm ² ) or more.

In the present invention, the full band ply 9A
And each of the edge band plies 9B are band cords 1
The cross-sectional area per wire of 1 is S (unit: mm ² ), and the modulus of the band cord at 2% elongation is M (unit: N)
/ Mm ² ), and the array density of band cords per 1 cm of band ply width is D (unit: book / cm), the elongation resistance value K (unit: N • book / cm) determined by the following formula is 110-110. 386
Limited to K = S × M × D / 100 (1) In addition, the modulus M is a value measured according to JIS L1017, and the array density D is one pitch of spiral winding as shown in FIG. The number of band cords 11 arranged between the lengths P (cm) is divided by the pitch length P.

This elongation resistance value K is determined by the band ply 9A,
9B is a value indicating the index of the resistance to elongation per unit width and per unit length of 9B, and the larger this value K, the greater the binding force to the belt layer 7. Then, the inventors made many trial tires (radial tires for passenger cars of size: 195 / 65R15 91H) in which the elongation resistance value K and the width WA of the edge band ply 9B in the tire axial direction were variously changed, and Researched the effects of road noise on road noise, passing noise, and rolling resistance.

FIG. 4 shows an example thereof, in which the abscissa (x axis) represents the elongation resistance value K and the ordinate (y axis) represents the belt layer width WB.
To the width WA of the edge band ply 9B (WA / W
B) is a plot of the road noise at that time on the z-axis perpendicular to the paper surface, and the three-dimensional relationship between the elongation resistance value K, the width ratio (WA / WB) and the road noise is viewed from the z-axis side. Shown as a bird's eye view. The curve in the figure corresponds to the contour line of road noise estimated from each plot value.

Road noise was measured by using domestically produced FF for each sample tire with rim (15 × 6JJ) and internal pressure (200 kPa).
Installed on all wheels of a passenger car (displacement 2000cc), run on a smooth road surface at a speed of 60km / h, measure the noise level (dB) of 250Hz band of 1/3 octave at the driver's left ear position, It is shown as the amount of change in the noise level based on the tire of Comparative Example 1. Therefore, the minus display indicates that the road noise is smaller than that of Comparative Example 1 and is favorable. The tire of Comparative Example 1 was a tire equipped with one full band ply made of nylon cord and had an elongation resistance value K of 80 (N · piece / cm) and a width ratio (WA / W
B) is 0.

The width ratio (WA / WB) is 0 to 0.5.
Is changing. When the width ratio (WA / WB) is 0, the edge band ply 9B does not exist and the band layer 9
Means one full band ply 9A. This is an embodiment of the pneumatic radial tire described in claim 1. When the width ratio (WA / WB) is 0.5, the left and right edge band plies 9B and 9B are substantially in contact with each other on the tire equator C, and apparently the band layer 9 has two full layers. Appears to consist of band ply 9A. However, in this aspect, since the band cords are not continuous at the tire equator, the restraining force to the belt layer 7 is different from that of the two full band plies, and thus the structure is clearly distinguished.

As is apparent from FIG. 4, the elongation drag value K
(Unit: N / piece / cm) 110 to 386, and width ratio (W
It can be confirmed that the road noise is superior to that of Comparative Example 1 including the nylon band in a region where A / WB) is in the range of 0 to 0.5 (hereinafter referred to as “region 1”). Further, the greater the elongation resistance value K, the greater the effect of reducing road noise. It is considered that this is because the damping effect on the belt layer 7 is increased by increasing the elongation resistance value K of the band ply. When the elongation resistance value K is the same, the width ratio (W
It can also be confirmed that the larger A / WB) is, the more advantageous it is to road noise.

In FIG. 5, the abscissa (x-axis) is the elongation resistance value K, and the ordinate (y-axis) is the width ratio (WA / WB) between the width WB of the belt layer and the width WA of the edge band ply 9B. ) Is a plot of rolling resistance at that time on the z axis perpendicular to the paper surface, and is a bird's-eye view of the three-dimensional relationship between the elongation resistance value K, the width ratio (WA / WB), and the rolling resistance as viewed from the z axis side. Show as. The curves in the figure correspond to the contour lines of rolling resistance estimated from the plotted values.

Rolling resistance is measured by riming each tire (15 × 6).
JJ), internal pressure (230 kPa), load (4.0 kN),
The rolling resistance value was measured with a rolling resistance tester under the condition of speed (80 km / h), and the rolling resistance value was divided by the load to obtain the value. The evaluation is shown as the amount of change based on Comparative Example 1 above. Therefore, the positive display indicates the increase (deterioration) value of the rolling resistance from the comparative example 1, and the negative display indicates the comparative example 1 on the contrary.
It shows that the rolling resistance is smaller and that it is good.

A close inspection of FIG. 5 reveals that the rolling resistance is locally deteriorated unexpectedly in the vicinity of the width ratio (WA / WB) of 0.2 to 0.3. Further, the deterioration of the rolling resistance is remarkable when the elongation resistance value K is approximately 280 (N · piece / cm) or more. As a result of analysis by the inventors, the cause is
When the width ratio (WA / WB) of the edge band ply 9B is set to about 0.2 to 0.3, the radius of curvature of the tread surface in the central region between the edge band plies is locally reduced, and the contact pressure becomes uneven. It is supposed to be because. This is because the elongation resistance value K is set to 170 or less and the rolling resistance is less deteriorated when the restraining force on the belt layer 7 is relaxed. Further, when the elongation resistance value K is set in this range, the deterioration of the rolling resistance is reduced to such an extent that there is no need to consider it as a problem even in the entire range of the width ratio (WA / WB) of 0 to 0.5. Therefore, as one preferable combination for suppressing the deterioration of rolling resistance while suppressing road noise, when the elongation resistance value K is 110 or more and 170 or less, the width ratio (WA / WB) is 0 to 0.5 or less. , More preferably greater than 0 and less than or equal to 0.5.

Further examination of FIG. 5 reveals that the width ratio (WA / W
When B) is in the range of 0.47 to 0.50, rolling resistance tends to be less deteriorated and rather improved. this is,
It is presumed that this is based on the fact that the tread surface is widely kept flat by the wide edge band ply 9B. It is also understood that when the width ratio (WA / WB) is set in this range, the elongation drag value K has a good result in the range of 110 to 386. Therefore, as another combination for suppressing the deterioration of rolling resistance while suppressing road noise, when the elongation drag value K is 110 or more and 386 or less, the width ratio (WA / WB) is 047 or more and 0.50 or more.
Can be set to:

Further, when FIG. 5 is further examined, the width ratio (W
Even when A / WB) is in the range of 0.07 or less, the rolling resistance tends to be less deteriorated and rather improved. This is presumed to be based on the fact that the tread surface is kept flat over a wide range by the edge band ply 9B having a remarkably narrow width. When the width ratio (WA / WB) is set in this range, the elongation resistance value K is 110 to 280.
It can be seen that good results are obtained in the range of. Therefore,
As yet another combination for suppressing the deterioration of rolling resistance while suppressing road noise, when the elongation resistance value K is 110 or more and 280 or less, the width ratio (WA / WB) is 0.
˜0.07, more preferably greater than 0 and less than or equal to 0.07.

When these areas are summed up, the following areas in FIG. 5 are suitable in the form having the edge band ply. a) When the elongation resistance value K is 110 or more and less than 170,
Region where width ratio (WA / WB) is greater than 0 and 0.5 or less (hereinafter referred to as "region 2") b) When elongation resistance value K is 170 or more and 280 or less, b1) Width ratio (WA / A region in which WB) is greater than 0 and 0.07 or less (hereinafter referred to as "region 3"), or b2) a region in which the width ratio (WA / WB) is 0.47 or more and 0.5 or less (hereinafter, " Area 4 ") c) When the elongation resistance value K is larger than 280 and 386 or less, the width ratio (WA / WB) is 0.47 or more and 0.5 or less (hereinafter, referred to as" area 5 ").

In FIG. 6, the abscissa (x-axis) is the elongation resistance value K, and the ordinate (y-axis) is the width ratio (WA / WB) between the width WB of the belt layer and the width WA of the edge band ply 9B. ) Is a plot of the passing noise at that time on the z axis perpendicular to the paper surface, and is a bird's-eye view of the three-dimensional relationship between the extension drag value K, the width ratio (WA / WB) and the passing noise from the z axis side. Show as. Also, the curves in the figure correspond to contour lines of passing noise inferred from each plotted value.

The passing noise is based on the actual vehicle coasting test specified in JASO / C / 606. In addition to coasting a straight test course (asphalt road surface) at a passing speed of 53 km / h for a distance of 50 m, 7.5m to the side from the centerline and 1.2 from the road at the midpoint
The maximum level dB (A) of the passing noise is measured by a stationary microphone installed at the position m, and is shown as the amount of change in the noise level based on Comparative Example 1 above. Therefore,
The minus display shows the reduction value of the passing noise from Comparative Example 1 and is good.

A close examination of FIG. 6 reveals that the passing noise becomes worse when the elongation resistance value K and the width ratio (WA / WB) are increased to improve the restraining force to the belt layer. Specifically, when the elongation resistance value K is 340 or more, the width ratio (WA / WB) is remarkably poor in the range of 0.27 to 0.50. Further, when the width ratio (WA / WB) is larger than 0.40 and the elongation drag value K becomes larger than 280, the passing noise is significantly deteriorated. Therefore, in order to suppress a significant deterioration of passing noise, this range is excluded and the elongation drag value K and width ratio (WA / W
B) should be defined. Specifically, the range is as follows. d) When the elongation drag value K is 110 or more and 280 or less,
Width ratio (WA / WB) is greater than 0 and 0.5 or less (hereinafter referred to as "region 6") e) When the elongation resistance value K is greater than 280 and less than 340, the width ratio (WA / WB) Is greater than 0 and 0.4 or less (hereinafter referred to as "region 7"), f) When the elongation resistance value K is 340 or more and 386 or less,
The width ratio (WA / WB) is greater than 0 and less than 0.28 (hereinafter referred to as "region 8"),

In order to obtain the most preferable pneumatic radial tire capable of reducing road noise while minimizing the deterioration of passing noise and rolling resistance, the overlapping portions of the regions 1 to 8 may be determined. This area is as follows. g) When the elongation drag value K is 110 or more and 170 or less,
When the width ratio (WA / WB) is greater than 0 and 0.5 or less h) and the elongation resistance value K is greater than 170 and 280 or less, the width ratio (WA / WB) is greater than 0 and 0. .07
Or less, or 0.47 or more and 0.50 or less

Table 1 shows other experimental data, and the evaluation method was the same as above. Further, in each embodiment, the elongation resistance value K of the full band ply 9A and the elongation resistance value K of the edge band ply 9B are set to be the same, but they may be different.

[0036]

[Table 1]

In the present invention, the individual values of the cross-sectional area S, the modulus M, and the array density D of the band cord are not particularly restricted, but the modulus M is 1000.
0N / mm ² or more, further 12000N / mm ² or more. If the modulus M is too small, the cross-sectional area S and the array density D are increased in order to increase the elongation resistance value K, and the tire molding tends to be difficult, and the durability tends to decrease.

Further, in the cross-sectional area S, 0.05 mm ² or more, further 0.08 mm ² or more, further 0.13 to
0.35 mm ² is preferable, and when the cross-sectional area S is too small, it is necessary to increase the modulus M and the array density D in order to increase the elongation resistance value K, which makes it difficult to select the material and the same problems as described above. There is. On the other hand, if the cross-sectional area S is too large, the moldability of the tire tends to decrease.

The array density D is preferably 4 to 16 (lines / cm), more preferably 7 to 13 (lines / cm). If the array density D is too small, the elongation resistance value K is increased. In addition, since the cross-sectional area S and the modulus M become large, the manufacturing cost of the tire increases and the durability of the tire tends to decrease. On the other hand, if the array density D is too large, the rubber adhesion tends to decrease and the tire durability tends to decrease.

Although the embodiments of the present invention have been described in detail above, the pneumatic radial tire of the present invention can be applied not only to passenger cars but also to various radial tires for small trucks, heavy loads, motorcycles, and the like. However, the present invention is not limited to the illustrated embodiment, and various modifications may be made and implemented.

[0041]

As described above, according to the invention described in claim 1, the full band ply is formed in the band layer, and in the invention described in claim 2,
By using the edge band ply and the full band ply for the band layer and limiting the extension resistance value K of each band ply, the road noise can be significantly reduced.

When the elongation resistance value and the width ratio of the edge band ply to the belt layer are regulated within the respective predetermined ranges, the road noise reducing effect is effectively exerted. It is possible to suppress deterioration of passing noise and rolling resistance.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a pneumatic radial tire of the present invention.

FIG. 2 is a perspective view illustrating a band-shaped ply used for a band layer.

FIG. 3 is a schematic cross-sectional view illustrating a method for winding a strip ply.

FIG. 4 is a graph showing the relationship between elongation resistance value K, width ratio (WA / WB), and road noise.

FIG. 5 is a graph showing the relationship between elongation resistance value K, width ratio (WA / WB), and rolling resistance.

FIG. 6 is a graph showing the relationship between elongation resistance value K, width ratio (WA / WB), and passing noise.

[Explanation of symbols]

2 tread section 3 Side wall part 4 bead section 5 bead core 6 carcass 7 Belt layer 9 band layers 9A edge band ply 11 band cord 13 strip plies

Claims (5)

[Claims] 1. A belt layer disposed inside a tread portion and outside in a radial direction of a carcass, and a single full band ply disposed outside the belt layer in a radial direction and covering substantially the entire width of the belt layer. A pneumatic radial tire having a band layer comprising: a full band ply, wherein one band cord or a plurality of band cord aligners is embedded in a topping rubber, and a tape-shaped band ply is spirally formed. This full band ply is formed by winding, and this full band ply has a cross-sectional area of one of the band cords S (unit: mm ² ) and a modulus at an elongation of 2% of the band cords M (unit: N). / Mm ² ),
The array density of band cords per 1 cm width of the full band ply is D (unit: book / cm), and the elongation resistance value K (unit: N. book / cm) determined by the following formula is 110 to 386. A characteristic pneumatic radial tire. K = S × M × D / 100 (1) 2. A pneumatic radial tire comprising a belt layer disposed inside a tread portion and radially outside a carcass, and a band layer disposed radially outside the belt layer, the pneumatic radial tire comprising: The band layer is composed of one full band ply covering substantially the entire width of the belt layer, and both edge band plies arranged on both ends of the belt layer and outside thereof, and the full band ply and the edge band ply. The ply is formed by spirally winding a tape-shaped strip-shaped ply in which one band cord or a plurality of aligned band cords are embedded in a topping rubber. The cross-sectional area per wire is S (unit: mm ² ) and the band cord elongation is 2%.
The modulus at time is M (unit: N / mm ² ), and the array density of band cords per 1 cm of the width of the band ply is D
(Unit: book / cm) Elongation resistance value K determined by the following formula
A pneumatic radial tire characterized in that (unit: N · piece / cm) is set to 110 to 386. K = S × M × D / 100 (1) 3. The elongation resistance value K of the edge band ply.
(Unit: N · piece / cm) and a width ratio (W that is a ratio of the width WA of the edge band ply to the width WB of the belt layer).
A / WB), when the elongation resistance value K is 110 or more and 170 or less,
When the width ratio (WA / WB) is greater than 0 and 0.5 or less and the elongation drag value K is greater than 170 and 280 or less, the width ratio (WA / WB) is greater than 0. And 0.07 or less, or 0.47 or more and 0.5
The width ratio (WA / WB) is 0.47 or more and 0.5 or less when the elongation resistance value K is larger than 280 and 386 or less. Pneumatic radial tire. 4. An elongation resistance value K of the edge band ply.
(Unit: N · piece / cm) and a width ratio (W that is a ratio of the width WA of the edge band ply to the width WB of the belt layer).
A / WB), when the elongation resistance value K is 110 or more and 280 or less,
When the width ratio (WA / WB) is greater than 0 and 0.5 or less and the elongation drag value K is greater than 280 and less than 340, the width ratio (WA / WB) is greater than 0. And 0.4 or less, and when the elongation drag value K is 340 or more and 386 or less, the width ratio (WA / WB) is greater than 0 and 0.2.
The pneumatic radial tire according to claim 2, wherein the pneumatic radial tire is less than 8. 5. The elongation resistance value K of the edge band ply.
(Unit: N · piece / cm) and a width ratio (W that is a ratio of the width WA of the edge band ply to the width WB of the belt layer).
A / WB), when the elongation resistance value K is 110 or more and 170 or less,
When the width ratio (WA / WB) is greater than 0 and 0.5 or less and the elongation drag value K is greater than 170 and 280 or less, the width ratio (WA / WB) is greater than 0. And 0.07 or less, or 0.47 or more and 0.50
The pneumatic radial tire according to claim 2, wherein: