JP2735471B2 - Radial tire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial tire, and more particularly to a radial tire capable of reducing fuel consumption of a vehicle.

[0002]

2. Description of the Related Art In recent years, global environmental problems such as ozone depletion, acid rain and the global greenhouse effect have been raised. Since these problems are largely due to components in the exhaust gas generated by the combustion of vehicle fuel such as gasoline, reducing the amount of vehicle fuel combustion can be an effective solution to these problems.

[0003] For this reason, for example, in North America, basic laws relating to fuel economy such as gas guzzler tax and company average fuel economy (CAFE) are under discussion. As technology development corresponding to CAFE, improvement of engine and other efficiency, reduction of energy loss in each part of the car,
Research is being conducted on reducing the weight of cars. That is, reduction of energy loss and weight reduction of tires are one solution to the above problem.

In order to reduce tire energy loss,
Decrease in tan δ peak temperature of cap tread (measures
-1) is performed, but when the tan δ peak temperature decreases, the wet grip tends to decrease. For the same purpose, the carbon content of the cap tread is reduced (measure-2). However, when the carbon content is reduced, the wet / dry grip tends to decrease, and the wear resistance tends to decrease. In addition, tire energy loss can be reduced by adopting a cap / base structure for the tread and reducing the carbon content of the base tread rubber (measures). However, when the carbon content of the base tread rubber is reduced, the rigidity is reduced. Therefore, the steering stability tends to deteriorate. Further, for the same purpose, the energy loss of the sidewall rubber is reduced by reducing (countermeasure) the carbon content of the sidewall rubber. However, when the carbon content of the sidewall rubber is reduced, the rigidity is reduced. Driving stability tends to deteriorate.

In order to reduce the weight of the tire, the groove depth of the cap tread rubber is reduced (measures). However, if the groove depth is reduced, the life of the tire tends to be shortened. For this purpose, the thickness of the sidewall is reduced (measures). However, when the thickness of the sidewall is reduced, the steering stability tends to deteriorate due to insufficient rigidity of the tire. Further, although the weight is reduced by reducing the volume of the bead apex (measures), the steering stability tends to deteriorate when the bead apex is reduced.

[0006]

The above-mentioned measure-1,
-2-By combining the measures, a light tire with small energy loss can be obtained and the fuel efficiency of the car can be reduced.
Such tires have poor steering stability such as grip and steering wheel responsiveness.

In order to improve steering stability, tires containing short fibers in components such as a base tread, sidewalls and bead filler have been devised (JP-A-59-204637 and JP-A-59-204637). −204
Nos. 638, 61-25605, 63-2
63104) cannot reduce energy loss and reduce weight.

The present invention has been made in view of the above problems, and has as its object to reduce energy loss, reduce weight,
It is an object of the present invention to provide a radial tire that can provide excellent vehicle steering stability.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to provide a cap tread comprising a rubber composition having a tan δ peak temperature of -30 ° C. or more after vulcanization, a rubber component of 100 parts (parts by weight, hereinafter the same). 30-90mg of iodine adsorption
/ G of a rubber composition containing 30 parts or less of carbon black and 10 parts or more of short fibers, wherein the short fibers are oriented substantially in the axial direction (hereinafter, referred to as the axial direction) of the tire. Iodine adsorption amount per part 30
A rubber composition containing 30 parts or less of carbon black of up to 90 mg / g and 10 parts or more of short fibers, wherein the short fibers are oriented in the circumferential direction of the tire, and iodine is adsorbed on 100 parts of the rubber component. Amount 60-100mg
/ G of a carbon composition comprising 65 parts or more of carbon black and 20 parts or more of short fibers, wherein the short fibers are oriented in an axial direction or a direction intersecting the axial direction of the tire. Achieved by tires.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The radial tire of the present invention is a tire characterized by a cap tread, a base tread, a sidewall and a bead apex.

Cap Tread The cap tread of the radial tire of the present invention has a tan δ peak temperature after vulcanization of −30 ° C. or higher, preferably −3 ° C.
It consists of a rubber composition at 0 to -10C. The balance between the rolling resistance and the wet grip changes depending on the tan δ peak temperature. When the tan δ peak temperature is lower than −30 ° C., the rolling resistance decreases but the wet grip tends to deteriorate.

The rubber component of the rubber composition is not particularly limited, but solution-polymerized SBR is preferred because of its property of lowering rolling resistance and improving wet grip. This rubber composition is usually 40 to 80 parts of carbon, 1 to 40 parts of oil, 1 to 3 parts of wax,
Standard grip-oriented, LRR comprising 1-3 parts of anti-aging agent, 1-3 parts of sulfur, 1-2 parts of accelerator
Formulations such as (low rolling resistance) directivity are applied.

The thickness of the cap tread is usually 5 to 9
mm.

Base Tread The rubber composition constituting the base tread of the present invention has an iodine adsorption amount of 30 to 90 mg / g, preferably 30 to 70 mg / g.
/ G of carbon black per 100 parts of the rubber component is 30 parts or less, preferably 5 to 30 parts. If the iodine adsorption amount is less than 30 mg / g, the steering stability deteriorates,
If it exceeds 90 mg / g, the rolling resistance tends to be deteriorated (increased). If the amount of carbon black exceeds 30 parts, the rolling resistance tends to deteriorate.

The rubber composition constituting the base tread of the present invention further contains 10 parts or more, preferably 10 to 30 parts of short fibers with respect to 100 parts of the rubber component, and as shown in FIG. Are oriented in the base tread 1 in the axial direction of the tire 4. Here, the axial direction means a direction substantially orthogonal to the tire circumferential direction. When the amount of the short fibers is less than 10 parts, the elastic modulus in the axial direction decreases, the lateral rigidity decreases, the steering stability deteriorates, and the rolling resistance tends to increase. When the orientation direction of the short fibers is not the axial direction of the tire, for example, the circumferential direction, the steering stability and the rolling resistance are not improved. As this short fiber, for example, UBEPOL
-Short fibers grafted on natural rubber such as HE 0100 (manufactured by Ube Industries, Ltd.), i.e., having an average diameter of about 0.1 mm.
Nylon 6 having a size of 3 μm and an average length of about 300 μm can be used.

The rubber composition constituting the base tread of the present invention generally contains 30 parts by weight or less of carbon (may contain an iodine adsorption amount other than 30 to 90 mg / g) per 100 parts of the rubber component. It comprises 0 to 10 parts of oil, 0 to 2 parts of wax, 0 to 3 parts of an antioxidant, 1 to 3 parts of sulfur, and 1 to 2 parts of an accelerator.

The thickness of the base tread is usually 1 to 5 m
m. The total thickness of the base tread and the cap tread is usually about 10 mm.

The base tread used in the present invention can be produced, for example, by the following method.

Base Tread Manufacturing Method 1 The rubber, carbon black, short fibers and other additives described above are kneaded using a Banbury mixer to prepare a rubber composition for a base tread. This rubber composition 5
Is rolled using a calender roll 6 as shown in FIG. 3 to obtain a sheet having a thickness of 1 to 6 mm. In the case of the axial orientation, as shown in FIG. 3, sheet pieces having a longitudinal direction perpendicular to the rolling direction are cut out and joined so as to have a predetermined length to form a base tread.

Base Tread Preparation Method 2 The rubber composition for the base tread prepared by kneading as described above is extruded into a tube by an extruder. Thereby, the short fibers in the rubber composition are oriented parallel to the longitudinal direction of the tube. As shown in FIG. 4, this tubular extruded product is cut at a predetermined cutting angle θ (an angle with respect to a direction perpendicular to the tube axis).
To form a base tread by spirally cutting out a sheet piece. If the diameter of the tube is large enough and the cutting angle θ is small, the base tread will be oriented in the axial direction.

The rubber composition forming the sidewalls of the sidewall invention, iodine adsorption amount 30~90mg / g, preferably 30~70mg
/ G, carbon black is contained in an amount of 30 parts or less, preferably 10 to 30 parts with respect to 100 parts of the rubber component. If the iodine adsorption amount is less than 30 mg / g, the steering stability tends to deteriorate, and if it exceeds 90 mg / g, the rolling resistance tends to deteriorate. If the amount of carbon black exceeds 30 parts, the rolling resistance tends to increase.

The rubber composition constituting the side wall of the present invention further contains 10 parts or more, preferably 10 to 30 parts of short fibers with respect to 100 parts of the rubber component, and as shown in FIG. Are oriented in the circumferential direction of the tire 4 in the sidewall 3. If the amount of the short fibers is less than 10 parts, the handling stability tends to deteriorate. If the orientation direction of the short fibers is not the circumferential direction of the tire, for example, if it is the axial direction, the steering stability is not improved. As the short fibers, for example, the above-mentioned UBEPOL-HE 0100 (manufactured by Ube Industries, Ltd.) can be used.

The rubber composition constituting the side wall of the present invention usually contains 30 parts or less of carbon (i.e., one having an iodine adsorption amount other than 30 to 90 mg / g) per 100 parts of the rubber component. It comprises 0 to 10 parts of oil, 1 to 3 parts of wax, 2 to 5 parts of antioxidant, 1 to 3 parts of sulfur, and 1 to 2 parts of accelerator.

The thickness of the sidewall is usually 1 to 5 m
m.

In the method 1 for producing a base tread,
As shown in FIG. 3, a sheet having a predetermined length whose longitudinal direction is the rolling direction may be cut out to form a side wall, or may be manufactured by extruding with an extruder by a conventional method.
However, it is preferable that the sidewall is formed by the ORBI method. The ORBI method is a method in which a string-shaped extrudate is wound around a side wall portion by an extruder and formed, and since there is no joint, there is no opening at the time of processing the joint portion, and the periphery is uniform. It is preferred in that it is molded into For example, in a normal molding method in which a sidewall integral extrudate is molded and inflated, the green strength in the circumferential direction is high, and the joint separates during inflation.

Bead Apex The rubber composition constituting the bead apex of the present invention has an iodine adsorption amount of 60 to 100 mg / g, preferably 60 to 9 mg / g.
0 mg / g of carbon black is contained in an amount of 65 parts or more, preferably 65 to 100 parts, based on 100 parts of the rubber component. When the iodine adsorption amount is less than 60 mg / g, the steering stability is deteriorated, and when it is more than 100 mg / g, extrusion tends to be difficult. If the amount of carbon black is less than 65 parts, steering stability tends to deteriorate.

The rubber composition constituting the bead apex of the present invention further contains 20 parts or more, preferably 20 to 50 parts of short fibers with respect to 100 parts of the rubber component. In the axial direction or a direction intersecting the axial direction. Here, the direction intersecting with the axial direction means that the angle intersecting with the axial direction is ± 30 to 6
0 °, preferably ± 45 °. If the amount of the short fibers is less than 20 parts, the handling stability tends to deteriorate. If the orientation direction of the short fibers is not the axial direction of the tire or the direction intersecting the axial direction, for example, the circumferential direction, the steering stability is not improved. As the short fibers, for example, the above-mentioned UBEPOL-HE 0100 (manufactured by Ube Industries, Ltd.) can be used.

The rubber composition constituting the bead apex of the present invention is generally used in an amount of 50 to 80 parts per 100 parts of the rubber component.
Parts of carbon (total amount including iodine adsorption amount other than 30 to 100 mg / g), 0 to 5 parts of oil, 0 to 2 parts
Parts of wax, 0 to 3 parts of an antioxidant, 2 to 6 parts of sulfur, and 2 to 5 parts of an accelerator.

The height of the bead apex is usually 10
It is about 70 mm.

The radial tire of the present invention is manufactured by molding and then vulcanizing an unvulcanized rubber compounded and mixed by a general manufacturing method, through steps such as calendering, topping and extrusion.

The radial tire of the present invention is particularly suitable for passenger cars and commercial vehicles.

Hereinafter, the present invention will be described with reference to Production Examples and Examples, but the present invention is not limited thereto. The method of testing the tires and the method of expressing the results in Production Examples and Examples are listed below.

Rolling resistance: The internal pressure of the tire is 2.5 kg
The rolling resistance was measured using a uniaxial drum tester at a speed of 80 km / h under a load of 350 kgf. The result is expressed as a relative value when the reference tire is set to 100, and the smaller the index, the better.

Steering wheel responsiveness / grip (steering stability): The tires to be tested were mounted on four wheels of a 1600 cc class domestic FF vehicle, and the steering stability was evaluated on a Sumitomo Rubber Okayama test course. The steering wheel responsiveness is the responsiveness of the vehicle to the steering wheel operation during straight running, and the grip is the limit speed and behavior when the vehicle starts sliding due to centrifugal force during coupling. Expressed by the method. The higher the score, the better, and those with a + indicate better at that point.

Wet brake: The tires to be tested are mounted on the same four wheels of the passenger car as used for steering stability,
On the test course, the water is sprayed on the asphalt road surface, and the braking distance μ from the speed of 40 km / h to the stop is determined by μ.

[0036]

(Equation 1)

Was calculated. The result is expressed as a relative value with the reference tire being 100, and the larger the index, the better.

Ride comfort: The tires to be tested are mounted on the same four-wheeled passenger cars as those used for steering stability, and shocks on various road surfaces (such as stone crush roads, step roads, and repair roads) on the test course. The feeling, dumping, hardness and the like were evaluated. The display method of the result is the same as the steering stability.

Table 1 shows the compositions of members other than those manufactured as characteristic constituent members in the manufacturing examples.

[0040]

[Table 1]

Production Example 1 (cap tread) 60 parts of solution-polymerized SBR (15% by weight of bound styrene, vinyl content of 30 mol%), 40 parts of NR, 60 parts of N351 (carbon black), 25 parts of aromatic oil, wax 1. 5 parts, antioxidant 6 PPD 1.5 parts, stearic acid 2 parts, zinc white 3 parts, sulfur 1.75 parts, accelerator C
A cap tread rubber was prepared by kneading in a Banbury using 1.5 parts of Z. Further, a base tread rubber was prepared using the composition of the base tread shown in Table 1. These rubbers were extruded by an extruder so that the cap tread was in the upper layer and the base tread was in the lower layer, thereby preparing a tread having a cap / base structure.
Molding and vulcanization are performed using this tread and the sidewalls and bead apex having the compositions shown in Table 1 to obtain DUNL except for the cap tread, the base tread, the sidewalls and the bead apex.
A radial tire A (185 / 65R14) corresponding to OP SP7 (manufactured by Sumitomo Rubber Industries, Ltd.) was manufactured. The rolling resistance and the wet brake were tested for the radial tire A. The rubber was taken out from the cap tread, and the tan δ peak temperature was measured.

The composition of this cap tread rubber and t
Table 2 shows the an δ peak temperature and the test results of the radial tire A.

As shown in Table 2, radial tires B, C and D were produced in the same manner as described above with the same cap tread rubber composition except that the rubber and carbon black compositions were changed. Table 2 shows the results of testing the tan δ peak temperature of each cap tread, the rolling resistance of the tire, and the wet brake.

The radial tire D is a tire having general wet grip performance, and shows the rolling resistance and wet brake test results of other tires based on the radial tire D.

[0045]

[Table 2]

From the results shown in Table 2, it can be seen that when the tan δ peak temperature after vulcanization of the cap tread is lower than −30 ° C., the rolling resistance decreases but the wet grip deteriorates.

Production Example 2 (base tread) 70 parts of NR, 30 parts of BR, short fiber (UBEPOL-HE)
0100 short fibers) 15 parts, FEF 10 parts, aromatic oil 5 parts, phenolic resin 3 parts, wax 1.5 parts, antioxidant 6PPD 2 parts, stearic acid 2
, 4 parts of zinc white, 2 parts of sulfur and 1.3 parts of accelerator CZ, and kneaded in a Banbury to prepare a base tread rubber. Further, cap tread rubber was prepared using the cap tread composition shown in Table 1.
When no short fiber is blended or when the short fiber is oriented in the tire circumferential direction, these rubbers are extruded by an extruder so that the cap tread is in the upper layer and the base tread is in the lower layer, so that the cap / base is extruded. A tread of the structure was prepared. When the short fibers were oriented in the axial direction, the cap tread was extruded. Separately, the base tread was cut out from a calender sheet and bonded at the time of molding. By performing molding and vulcanization using this tread and the sidewall and bead apex having the composition shown in Table 1, a radial tire corresponding to DUNLOP SP7 except for the cap tread, the base tread, the sidewall and the bead apex ( A)
(185 / 65R14). With respect to the radial tire (A), tests of rolling resistance and steering stability (handle response) were performed.

Table 3 shows the composition of the base tread rubber, the orientation direction of the short fibers in the base tread rubber, and the test results of the radial tire (A).

As shown in Table 3, the radial tires (B) to (B) were prepared using the same base tread rubber composition as described above except that the composition of rubber, carbon black and short fibers and the orientation direction of the short fibers were changed. (I) was produced. Here, the iodine adsorption amount of carbon black is FE
F43 mg / g, HAF 82 mg / g, ISAF121
mg / g, and ISAF is not applicable to the present invention. Table 3 shows the results of testing the rolling resistance and steering stability (handle response) of each radial tire.

The radial tire (B) is a tire having general rolling resistance and steering stability, and the test results of the rolling resistance and steering stability (handle response) of other tires based on the radial tire (B) Represents

[0051]

[Table 3]

From the results shown in Table 3, the carbon black was FE
HAF improves the steering stability more than F, and if the blending amount of the short fiber is less than 10 parts, the steering stability is inferior,
When the blending amount of carbon black is more than 30 parts, the rolling resistance is poor (increased), and when the iodine adsorption amount of carbon black is more than 90 mg / g, the rolling resistance is poor, and when the orientation direction of the short fibers is the circumferential direction, the steering is performed. It can be seen that the stability (handle response) is poor.

Production Example 3 (side wall) NR 45 parts, BR 55 parts, short fiber (UBEPOL-HE)
15 parts, FEF 20 parts, aromatic oil 5 parts, wax 2 parts, antioxidant 6P
PD 3 parts, stearic acid 2 parts, zinc white 3 parts, sulfur 1.
Using 5 parts and 1 part of an accelerator CZ, the mixture was kneaded in a Banbury and extruded into a predetermined shape by an extruder to prepare a sidewall. By molding and vulcanizing using this sidewall and the cap tread, base tread and bead apex whose composition is shown in Table 1, DUNLOP SP is used except for the cap tread, base tread, sidewall and bead apex.
7 (A) (185 / 65R1)
4) was manufactured. About this radial tire (1),
Rolling resistance and steering stability (handle response) were tested.

Table 4 shows the composition of the sidewall rubber, the orientation direction of the short fibers in the sidewall, and the test results of the radial tire (1).

As shown in Table 4, the composition of the rubber, carbon black and short fibers and the composition of the side wall rubber were the same as those described above except that the orientation direction of the short fibers was changed. (8) was produced. Table 4 shows the results of testing the rolling resistance and steering stability (handle response) of each radial tire.
Shown in

The radial tire (4) is a tire having general rolling resistance and steering stability, and the test results of rolling resistance and steering stability (handle response) of other tires based on the radial tire (4) Represents

[0057]

[Table 4]

From the results shown in Table 4, it can be seen that when the fibers are oriented in the axial direction, the steering stability (handle response) is poor. In addition, the radial tire (8) is slightly inferior in responsiveness to the steering wheel as compared with the standard (4) because the amount of short fibers is as small as 5 parts.

Production Example 4 (Bead Apex) 100 parts of NR, short fiber (UBEPOL-HE 0100)
Medium short fiber) 30 parts, HAF 70 parts, PR12686 resin (thermosetting resin) (Sumitomo Durez Co., Ltd.) 15
Parts, phenolic resin (adhesive) 3 parts, stearic acid 2 parts, zinc white 5 parts, sulfur 3 parts, accelerator CZ 3.8 parts,
Using 0.4 part of the retarder PVI, the mixture was kneaded in a Banbury and extruded into a predetermined shape to prepare a bead apex. The bead apex and the cap tread, base tread and sidewall shown in Table 1 are molded and vulcanized to obtain a DUNLOP SP7 other than the cap tread, base tread, sidewall and bead apex. Radial tire (A) (185 / 65R14) was manufactured. With respect to this radial tire, tests for rolling resistance and steering stability (handle response) were performed.

Table 5 shows the composition of the bead apex, the orientation direction of the short fibers in the bead apex, and the test results of the radial tire.

As shown in Table 5, a radial tire and a tire were manufactured by the same method as described above using the same bead apex rubber composition except that the compositions of rubber, carbon black and short fibers and the orientation direction of the short fibers were changed. did. Table 5 shows the results of testing the rolling resistance and steering stability (handle response) of each radial tire.
Shown in

A radial tire is a tire having general rolling resistance and steering stability, and the results of tests of rolling resistance and steering stability of other tires based on the radial tire are shown.

[0063]

[Table 5]

From the results in Table 5, it can be seen that when short fibers are contained in the bead apex while being oriented in the axial direction or the direction intersecting with the axial direction, the steering stability (handle response) is improved. Recognize.

[0065] Using the formulation T _B of the cap tread shown in Example 1 in Table 6, the cap tread was prepared by kneading and extrusion. Here, the iodine adsorption amount of N-351 which is carbon black is 68 mg / g. The tan δ peak temperature of this cap tread was measured to be −24 ° C.

[0066] Using the formulation B _B of the base tread shown in Table 6, and the base tread prepared by kneading and extrusion.

[0067] Using the formulation S _B of the sidewall shown in Table 6, the side wall was prepared by kneading and extrusion.

Formulation A _{B of the} bead apex shown in Table 6
Was used to prepare a bead apex by kneading and extruding.

By performing molding and vulcanization using these cap tread, base tread, sidewall and bead apex, a radial tire (185 / 65R14) corresponding to DUNLOP SP7 is obtained except for these four components. Manufactured. The orientation direction of the short fibers is the axial direction in the base tread, the circumferential direction in the sidewall, and the axial direction in the bead apex. Table 7 summarizes the construction of this tire.

The radial tire was weighed and tested for rolling resistance, grip (steering stability), steering wheel responsiveness (steering stability), and riding comfort. Table 7 also shows the results.

Table 8 shows the dimensions of each component.

Examples 2 and 3 The same tires were produced in the same manner as in Example 1 except that the cap tread, base tread, sidewall and bead apex shown in Table 7 were used. Table 7 also shows the results of the same test as in Example 1 performed on this tire. Table 8 shows the dimensions of each component.

Comparative Examples 1 to 3 Radial tires similar to those of Example 1 were produced using the compositions shown in Table 6 and the configuration shown in Table 7.

Table 7 shows the weight, rolling resistance, grip, handle response and ride comfort of these radial tires.

The tire of Comparative Example 3 is a normal tire having a general rolling resistance, and the test results are shown based on Comparative Example 3.

Table 8 shows the dimensions of each component.

[0077]

[Table 6]

[0078]

[Table 7]

[0079]

[Table 8]

In Table 6, T _A , B _A , S _A , S _C ,
A _A is the conventional general formulation.

From the results of Examples 1 to 3 and Comparative Examples 1 to 3, the radial tire of the present invention is light in weight, has very low rolling resistance, and can provide excellent steering stability and ride comfort. I understand.

[0082]

The radial tire according to the present invention is lightweight and has low rolling resistance, so that the fuel efficiency of a mounted vehicle can be improved. Further, since the steering stability (grip and steering wheel responsiveness) is excellent, safe high-speed driving can be ensured, and further excellent ride comfort can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a state in which short fibers are oriented in an axial direction of a tire in a base tread.

FIG. 2 is a schematic perspective view showing a state in which short fibers are oriented in a circumferential direction of a tire in a sidewall.

FIG. 3 is an explanatory view showing a method for producing a base tread and sidewalls.

FIG. 4 is an explanatory view showing a method of cutting out a base tread from a tubular extrudate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base tread 2 Short fiber 3 Side wall 4 Tire 5 Rubber composition 6 Calendar roll

Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI B60C 15/06 B60C 15/06 B (56) References JP-A-55-11053 (JP, A) JP-A-3-220003 (JP, A JP-A-63-156840 (JP, A) JP-A-54-132904 (JP, A) JP-A-63-156841 (JP, A) JP-A-57-104405 (JP, A) JP-A-2- 162101 (JP, A) JP-A-63-95243 (JP, A) JP-A-63-263104 (JP, A) JP-A-5-16621 (JP, A) JP-B 5-39805 (JP, B2) JP-B-57-20164 (JP, B2) JP-B-63-66856 (JP, B2)

Claims (2)

(57) [Claims] (A) The tan δ peak temperature after vulcanization is-
A cap tread made of a rubber composition having a temperature of 30 ° C. or more;
A base tread comprising a rubber composition containing 30 parts by weight or less of carbon black of 10 to 90 mg / g and 10 parts by weight or more of short fibers, wherein the short fibers are substantially oriented in the axial direction of the tire; Iodine adsorption amount 30 per 100 parts by weight
A sidewall composed of a rubber composition containing 30 parts by weight or less of carbon black of 30 to 90 mg / g and 10 parts by weight or more of short fibers, wherein the short fibers are oriented in the circumferential direction of the tire;
And (D) an iodine adsorption amount of 60 with respect to 100 parts by weight of the rubber component.
１００100 mg / g of carbon black at least 65 parts by weight,
Radial tire comprising a bead apex comprising a rubber composition containing at least 20 parts by weight of short fibers, wherein the short fibers are oriented substantially in the axial direction of the tire or in a direction substantially intersecting the axial direction. . 2. The radial tire according to claim 1, wherein the sidewall is formed by an ORBI method.