JP2023093964A - pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire which can reduce the rolling resistance by reducing the weight of the tire while improving the external damage resistance of a sidewall.SOLUTION: A pneumatic tire 1 includes: a bead 10; a sidewall 20; a tread 30; and a carcass ply 50. The carcass ply 50 includes a first carcass ply 51, a second carcass ply 52 and a third carcass ply 53. The first carcass ply 51 is continuous in the tire width direction X over the bead 10. The second carcass ply 52 and the third carcass ply 53 have a second ply piece 52A and a third ply piece 53A which are divided in the tire width direction X. The second ply piece 52A and the third ply piece 53A have tire width direction inner ends 52a, 53a which are arranged so as to be apart from each other in the tire width direction X on the tread 30. The tire width direction inner end 52a of the second ply piece 52A and the tire width direction inner end 53a of the third ply piece 53A are arranged so as to be apart from each other in the tire width direction X.SELECTED DRAWING: Figure 1

Description

The present invention relates to pneumatic tires.

In passenger car tires, the damage resistance of sidewalls during running on rough roads is a problem. In particular, for heavy-duty tires mounted on light trucks and the like, it is important to ensure the resistance of the sidewalls to external damage.

Conventionally, the number of carcass plies arranged in the sidewall has been increased in order to ensure the trauma resistance of the sidewall (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2020-152380

By increasing the number of carcass plies, the strength of the sidewall can be improved and the resistance to external damage can be ensured, but the weight of the tire increases. As the weight of the tire increases, the rolling resistance increases, so it is desired to reduce the weight of the tire while improving the strength of the sidewall.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pneumatic tire capable of reducing the rolling resistance by reducing the weight of the tire while improving the trauma resistance of the sidewall.

A pneumatic tire of the present invention includes a pair of beads, a pair of sidewalls extending radially outward from each of the pair of beads, a tread disposed between the pair of sidewalls, and the a carcass ply extending over a bead, the carcass ply comprising: a first carcass ply; a second carcass ply arranged outside the first carcass ply in the tire width direction; and a third carcass ply arranged outside the carcass ply in the tire width direction, wherein the first carcass ply is arranged continuously in the tire width direction across the pair of beads, and the second carcass ply and the third carcass plies each have a pair of second ply pieces and a pair of third ply pieces that are split in the tire width direction, and each of the pair of second ply pieces and the pair of third ply pieces have tire width direction inner ends that are spaced apart from each other in the tire width direction in the tread, the tire width direction inner ends of the pair of second ply pieces and the pair of third ply pieces The inner end in the tire width direction is arranged apart in the tire width direction.

ADVANTAGE OF THE INVENTION According to this invention, the pneumatic tire which can aim at reduction of rolling resistance by weight reduction of a tire can be provided, while improving the trauma resistance of a sidewall.

It is a tire width direction sectional view of a pneumatic tire concerning an embodiment. FIG. 2 is a partially enlarged view of FIG. 1;

Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 shows a cross section of a tire 1, which is a pneumatic tire according to an embodiment, in the tire width direction. FIG. 2 is an enlarged view of a part of FIG. 1, and is a cross-sectional view showing a portion extending from a tread 30 (to be described later) to the bead 10 on the vehicle outer side D1.

A tire 1 according to the embodiment is, for example, a pneumatic tire for a passenger car. In addition, the tire 1 according to the embodiment can be used for various vehicles other than passenger cars, such as light trucks, trucks, and buses.

The structure of the tire 1 is bilaterally symmetrical in a cross section in the tire width direction. In FIG. 1, symbol S1 is the tire equatorial plane. The tire equatorial plane S1 is a plane orthogonal to the tire rotation axis (tire meridian) and located at the center in the tire width direction.

The cross-sectional view of FIG. 1 shows a no-load state in which the tire 1 is mounted on a specified rim and filled with a specified internal pressure. A standard rim refers to a standard rim defined by JATMA corresponding to a tire size. Further, the specified internal pressure is 180 kPa, for example, when the tire 1 is for a passenger car.

Here, the tire width direction is a direction parallel to the tire rotation axis, and is the lateral direction on the paper surface of FIG. 1 . In FIG. 1, it is illustrated as the tire width direction X. X1 is the outside in the tire width direction, and X2 is the inside in the tire width direction. The tire width direction outer side X1 is the direction away from the tire equatorial plane S1, and is the left side and the right side in FIG. The tire width direction inner side X2 is the direction approaching the tire equatorial plane S1, and is the center side of the paper surface in FIG.

Moreover, the tire radial direction is a direction perpendicular to the tire rotation axis, which is the up-down direction on the paper surface of FIG. 1 . In FIG. 1, it is illustrated as the tire radial direction Y. Y1 is the outside in the tire radial direction, and Y2 is the inside in the tire radial direction. The tire radial direction outer side Y1 is the direction away from the tire rotation axis, and is the upper side of the paper surface in FIG. The tire radial direction inner side Y2 is the direction toward the tire rotation axis, which is the lower side of the paper surface in FIG. 1 .

As shown in FIG. 1, the tire 1 includes a pair of beads 10 provided on both sides in the tire width direction, a pair of sidewalls 20 extending radially outward Y1 from each of the pair of beads 10, and a pair of sidewalls. 20, a belt 40 arranged on the tread 30, a carcass ply 50 extending from the tread 30 to a pair of beads 10, and an inner liner 60 arranged on the tire inner cavity side of the carcass ply 50. , is equipped with The tire 1 has a symmetrical structure in the tire width direction X with respect to the tire equatorial plane S1.

The bead 10 includes a bead core 11, a bead filler 12 extending from the bead core 11 to the tire radial direction outer side Y1, and a rim strip rubber 13.

The bead core 11 is an annular member in which a metal bead wire coated with rubber is wound multiple times in the tire circumferential direction. The bead core 11 is a member that serves to fix the inflated tire 1 to the rim.

As shown in FIG. 2 , the bead filler 12 has a tire radially outer end 12a that is the tip of the tire radially outer side Y1. The bead filler 12 has a tapered shape extending from the tire radial inner side Y2 to the tire radial outer end 12a.

The bead filler 12 is provided to increase the rigidity of the peripheral portion of the bead 10 and ensure high maneuverability and stability. The bead filler 12 is made of, for example, rubber having a higher hardness than the surrounding rubber member.

As shown in FIG. 1 , the rim strip rubber 13 further surrounds the outside of a carcass ply 50 that surrounds the bead core 11 and bead filler 12 . Rim strip rubber 13 contacts the inner portion of the rim on which tire 1 is mounted. A top portion 13a extending in the tire circumferential direction is formed on the outer surface of the rim strip rubber 13 on the tire width direction outer side X1. The top 13a of the rim strip rubber 13 constitutes a rim protector 14 that protects the rim from damage. The rim protector 14 is annularly continuous in the tire circumferential direction.

The sidewall 20 includes a sidewall rubber 21 arranged on the outer side X1 of the carcass ply 50 in the tire width direction. The sidewall rubber 21 constitutes the outer wall surface of the tire 1 . The sidewall rubber 21 is the portion that bends the most when the tire 1 acts as a cushion, and is generally made of flexible rubber having fatigue resistance. The radially inner Y2 end of the sidewall rubber 21 covers the radially outer Y1 end of the rim strip rubber 13 .

The tread 30 has tread rubber 31 . An endless belt 40 and a cap ply 45 are arranged on the tread 30 . The belt 40 is arranged on the tire radial direction outer side Y1 of the inner liner 60 . The cap ply 45 is arranged on the tire radial direction outer side Y1 of the belt 40 . The tread rubber 31 is arranged on the tire radial direction outer side Y1 of the cap ply 45 .

Belt 40 is a member that reinforces tread 30 . The belt 40 of the embodiment has a two-layer structure including an inner belt 41 arranged on the outer side Y1 in the tire radial direction of the inner liner 60 and an outer belt 42 arranged on the outer side Y1 in the tire radial direction of the inner belt 41. be. Both the inner belt 41 and the outer belt 42 have a structure in which a plurality of metal cords such as steel cords are covered with rubber. The belt 40 has an outer end portion 40B in which the inner belt 41 and the outer belt 42 overlap each other on the outer side X1 in the tire width direction.

In the belts 40, the inner belt 41 is wider than the outer belt 42. - 特許庁Therefore, as shown in FIG. 2, the tire width direction outer end 41A, which is the tip of the inner belt 41 on the tire width direction outer side X1, is located closer to the tire width direction outer end 42A, which is the tip of the tire width direction outer side X1 of the outer belt 42. are also arranged away from each other on the outer side X1 in the tire width direction. By providing the belt 40, the rigidity of the tire 1 is ensured, and the ground contact of the tread 30 to the road surface is improved.

The cap ply 45 is a member that reinforces the tread 30 together with the belt 40 . The cap ply 45 has, for example, a structure in which a plurality of insulating organic fiber cords such as polyamide fibers are covered with rubber.

As shown in FIG. 2, the tire width direction outer end portion 45B of the cap ply 45 is doubled by being folded inward from the tire radial direction outer side Y1. A tire width direction outer end 45A, which is the tip of the tire width direction outer side X1 of the cap ply 45, is positioned further to the tire width direction outer side X1 than the tire width direction outer end 41A of the inner belt 41. As shown in FIG. The tire width direction outer end 45B of the cap ply 45 covers and adheres to the tire width direction outer end 42B of the outer belt 42 and the tire width direction outer end 41B of the inner belt 41 .

Although the cap ply 45 of the embodiment has a single layer, it may have a structure of two or more layers. By providing the cap ply 45, it is possible to improve durability and reduce road noise during running.

As shown in FIG. 1 , the tread rubber 31 is arranged on the tire radial direction outer side Y1 of the cap ply 45 . The tread rubber 31 is a member that forms a tread 31a that comes into contact with the road surface during running. The tread surface 31a of the tread rubber 31 is provided with a tread pattern 32 composed of, for example, a plurality of grooves. As shown in FIG. 2 , the tire width direction outer end 31B of the tread rubber 31 is bent radially inward Y2 beyond the tire width direction outer end 45A of the cap ply 45 and is in contact with the carcass ply 50 . . As shown in FIG. 1 , the tire width direction outer end portion 31B of the tread rubber 31 is covered with the tire radial direction outer end portion 21B of the sidewall rubber 21 .

The carcass ply 50 constitutes a ply that forms the skeleton of the tire 1 . As shown in FIG. 1, the carcass ply 50 of the embodiment has a three-layer structure of a first carcass ply 51, a second carcass ply 52, and a third carcass ply 53 in order from the tire inner cavity side. Each of the first carcass ply 51 , the second carcass ply 52 , and the third carcass ply 53 includes a plurality of carcass cords (not shown) that form the frame of the tire 1 . The plurality of carcass cords extend, for example, along a plane along the tire width direction X and are arranged side by side in the tire circumferential direction. This carcass cord is composed of an insulating organic fiber cord such as polyester or polyamide. Each of the first carcass ply 51, the second carcass ply 52, and the third carcass ply 53 is configured by coating a plurality of carcass cords with rubber. Since the tire 1 has the carcass ply 50 having a three-layer structure, the strength of the sidewall 20 is improved, and the resistance to trauma of the tire 1 is improved.

The first carcass ply 51 is arranged on the innermost side of the tire in the carcass ply 50 and arranged in contact with the inner liner 60 on the outer side of the tire. The first carcass ply 51 is formed continuously in the tire width direction X across the pair of beads 10 without interruption. That is, as shown in FIG. 2, the first carcass ply 51 extends from the tread 30 at the center in the tire width direction to the pair of sidewalls 20, and further extends to the inner side X2 of the bead core 11 in the tire width direction. A ply main body portion 51a, a bent portion 51b that wraps around the bead core 11 from the first carcass ply main body portion 51a and is bent, a folded portion 51c that is folded back from the bent portion 51b to the tire radial direction outer side Y1, and the tire radial direction of the folded portion 51c. and a folded end 51d that is the tip of the outer side Y1.

The first carcass ply body portion 51a, the bent portion 51b, and the folded portion 51c are continuous. The end portion of the tire radially inner side Y2 of the first carcass ply main body portion 51a is disposed on the tire width direction inner side X2 of the bead core 11 and the bead filler 12 . The folded portion 51c is arranged on the tire width direction outer side X1 of the bead core 11 and the bead filler 12 . The bent portion 51 b is arranged on the inner side Y<b>2 in the tire radial direction of the bead core 11 and constitutes the innermost portion in the tire radial direction Y in the first carcass ply 51 . The folded portion 51c extends to the vicinity of the tire maximum width position 20W. The folded end 51d is arranged near the tire maximum width position 20W.

The second carcass ply 52 is arranged on the tire outer surface side of the first carcass ply 51 , and the third carcass ply 53 is arranged on the tire outer surface side of the second carcass ply 52 . Each of the second carcass ply 52 and the third carcass ply 53 has a hollow portion that is discontinuous at the central portion in the tire width direction, and is divided into both sides in the tire width direction X with the hollow portion interposed therebetween. configuration. Even though the tire 1 has the carcass ply 50 having a three-layer structure, the hollow portions of the second carcass ply 52 and the third carcass ply 53 reduce the weight and reduce the rolling resistance.

The second carcass ply 52 includes a pair of second ply pieces 52A split in the tire width direction X. As shown in FIG. The second carcass ply 52 has a discontinuous first hollow portion 52H at the central portion of the tread 30 in the tire width direction. The pair of second ply pieces 52A are embedded in the tire 1 so as to be arranged on both sides in the tire width direction X with the first hollow portion 52H interposed therebetween.

As shown in FIG. 2 , the second ply piece 52A has tire width direction inner ends 52a which are ends on the first hollow portion 52H side and face each other in the tire width direction X while being separated from each other. The tire width direction inner end 52a of the second ply piece 52A is arranged at the end portion of the tread 30 on the tire width direction outer side X1. The second ply piece 52A has a tire width direction inner end 52b including a tire width direction inner end 52a on the tire width direction inner side X2.

As shown in FIG. 2 , the second ply piece 52A extends from the inner end 52a in the tire width direction to the sidewall 20 and further extends to the inner side X2 in the tire width direction of the bead filler 12 in the bead 10. It has a portion 52c. The second ply piece 52A is a down ply and extends halfway through the bead filler 12 . A tire radially inner end 52 d , which is the tip of the second ply piece main body portion 52 c on the innermost tire radial direction Y<b>2 , does not reach the bead core 11 . A tire radial inner end 52 d of the second ply piece main body portion 52 c is arranged on the tire width direction inner side X<b>2 of the bead filler 12 .

Since the first carcass ply 51 does not have a hollow portion, the tire width direction inner end 52a of the second carcass ply 52 is arranged on the tire outer surface side of the first carcass ply 51 in the tread 30, and the inner liner No direct contact with 60. Therefore, interference between the tire width direction inner end 52a of the second carcass ply 52 and the inner liner 60 having lower strength than the belt 40 can be avoided.

The third carcass ply 53 includes a pair of third ply pieces 53A split in the tire width direction X. As shown in FIG. The third carcass ply 53 has a discontinuous second hollow portion 53H at the center portion of the tread 30 in the tire width direction. The pair of third ply pieces 53A are embedded in the tire 1 so as to be arranged on both sides in the tire width direction X with the second hollow portion 53H interposed therebetween.

As shown in FIG. 2 , the third ply piece 53A has tire width direction inner ends 53a which are ends on the side of the second hollow portion 53H and face each other in the tire width direction X while being separated from each other. The tire width direction inner end 53a of the third ply piece 53A is arranged at the end portion of the tread 30 on the tire width direction outer side X1. The third ply piece 53A has a tire width direction inner end portion 53b including a tire width direction inner end 53a on the tire width direction inner side X2.

The third ply piece 53A extends from the tire width direction inner end 53a to the sidewall 20 and further to the tire width direction inner side X2 of the bead filler 12 in the bead 10. A bent portion 53d that bends around the bead core 11 from the piece body portion 53c, a folded portion 53e that folds back from the bent portion 53d to the tire radial direction outer side Y1, and a folded end 53f that is the tip of the tire radial direction outer side Y1 of the folded portion 53e. and have

The third ply piece body portion 53c, the bent portion 53d and the folded portion 53e are continuous. The third ply piece main body portion 53c is in close contact with the tire outer surface side of the second ply piece main body portion 52c of the second carcass ply 52 . The tire radially inner end 52d, which is the end portion of the tire radially inner side Y2 of the second ply piece main body portion 52c, is positioned between the first carcass ply main body portion 51a and the third ply piece main body at the tire width direction inner side X2 of the bead filler 12. It is sandwiched between the portion 53c. The bent portion 53 d of the third carcass ply 53 is sandwiched between the bead core 11 and the bent portion 51 b of the first carcass ply 51 . The bent portion 53 d of the third carcass ply 53 constitutes the innermost portion in the tire radial direction Y of the third carcass ply 53 . The folded portion 53 e of the third carcass ply 53 is sandwiched between the bead core 11 and the bead filler 12 and the folded portion 51 c of the first carcass ply 51 . The folded portion 53e of the third carcass ply 53 extends from the tire maximum width position 20W to the tire radial direction outer side Y1. The folded end 53f of the third carcass ply 53 is arranged radially outward Y1 of the folded end 51d of the first carcass ply 51 and radially outward Y1 of the maximum tire width position 20W.

The inner liner 60 is arranged on the tire inner surface side between the pair of beads 10 . The inner liner 60 covers the inner surfaces of the belt 40 and the first carcass ply 51 in the area of the tread 30 . Also, the inner liner 60 covers the inner surface of the first carcass ply 51 in the region of the sidewall 20 . Further, the inner liner 60 covers the inner surface of the first carcass ply 51 in the region of the tire radially outer side Y1 of the bead 10 and covers the rim strip rubber 13 in the region of the tire radially inner side Y2 of the bead 10 .

The inner liner 60 is made of air permeable rubber and prevents the air inside the tire cavity from leaking to the outside.

Here, as the rubber used for the bead filler 12, a rubber having a higher hardness than at least the sidewall rubber 21 and the inner liner 60 is used. The hardness of rubber is a value (durometer hardness) measured with a type A durometer in an atmosphere of 23° C. in accordance with JIS K6253.

For example, when the hardness of the sidewall rubber 21 is used as a standard, the hardness of the bead filler 12 is preferably about 1.2 to 2.3 times the hardness of the sidewall rubber 21 . More preferably, the rim strip rubber 13 has a hardness of about 1 to 1.6 times the hardness of the sidewall rubber 21 . With such hardness, the balance between the flexibility of the tire and the rigidity around the bead 10 can be ensured.

As shown in FIG. 2, the tire width direction inner end 52a of the second carcass ply 52 and the tire width direction inner end 53a of the third carcass ply 53 are arranged apart in the tire width direction X. As shown in FIG. Either the inner end 52a in the tire width direction of the second carcass ply 52 or the inner end 53a in the tire width direction of the third carcass ply 53 may be arranged on the outer side X1 in the tire width direction. The tire width direction inner end 53a of the carcass ply 53 is arranged apart from the tire width direction inner end 52a of the second carcass ply 52 on the tire width direction outer side X1 by a distance L1. A tire width direction inner end 53 a of the third carcass ply 53 is arranged in a state of being sandwiched between the inner belt 41 and the second carcass ply 52 and is not in direct contact with the inner liner 60 .

This avoids failures caused by concentration of strain due to alignment of the inner ends 52a and 53a of the second carcass ply 52 and the third carcass ply 53 in the tire width direction. The distance L1 is preferably at least 10 mm from the viewpoint of more effectively avoiding failures caused by concentration of strain.

As shown in FIG. 2, the tire width direction outer end portion 40B of the belt 40, the tire width direction inner end portion 52b of the second ply piece 52A, and the tire width direction inner end portion 53b of the third ply piece 53A are separated from each other by the tire diameter. They are arranged overlapping in the direction Y. That is, the tire width direction inner end 52b of the second ply piece 52A and the tire width direction inner end 53b of the third ply piece 53A are aligned with the tire width direction outer end 41B of the inner belt 41 and the tire width direction outer end 41B of the outer belt 42. Covered by outer edge 42B. Therefore, the second ply piece 52A and the third ply piece 53A are suppressed from peeling off at the tire width direction inner end portions 52b and 53b.

As shown in FIG. 2, the tire width direction inner end 53a of the third ply piece 53A and the tire width direction outer end 42A of the outer belt 42 of the belt 40 are arranged apart in the tire width direction X. As shown in FIG. The tire width direction inner end 53a of the third ply piece 53A shown in the embodiment is located on the tire width direction inner side X2 by a distance L2 with respect to the tire width direction outer end 42A of the outer belt 42 narrower than the inner belt 41. are placed.

As a result, the tire width direction inner end 53a of the third ply piece 53A and the tire width direction outer end 42A of the outer belt 42 are aligned in the tire radial direction Y, thereby avoiding failures caused by strain concentration. be done. The distance L2 is preferably at least 10 mm from the viewpoint of more effectively avoiding failures caused by strain concentration, and more preferably from 10 mm to 50 mm from the viewpoint of weight reduction.

The tire 1 of the embodiment described above has the following effects.

(1) The tire 1 according to the embodiment includes a pair of beads 10, a pair of sidewalls 20 extending radially outwardly Y1 from each of the pair of beads 10, and a tread disposed between the pair of sidewalls 20. 30 and a carcass ply 50 extending from the tread 30 to the bead 10, wherein the carcass ply 50 is arranged on the first carcass ply 51 and on the outside X1 in the tire width direction of the first carcass ply 51. and a third carcass ply 53 arranged on the outer side X1 of the second carcass ply 52 in the tire width direction. The second carcass ply 52 and the third carcass ply 53, which are arranged continuously in the width direction X, respectively have a pair of second ply pieces 52A and a pair of third ply pieces 53A divided in the tire width direction X. , the pair of second ply pieces 52A and the pair of third ply pieces 53A each have tire width direction inner ends 52a, 53a that are arranged apart from each other in the tire width direction X in the tread 30, The tire width direction inner end 52a of the two-ply piece 52A and the tire width direction inner end 53a of the pair of third ply pieces 53A are arranged apart in the tire width direction X.

As a result, it is possible to reduce the rolling resistance by reducing the weight of the tire 1 while improving the trauma resistance of the sidewall 20 . Since the tire width direction inner ends 52a, 53a of the second ply piece 52A and the third ply piece 53A are arranged apart in the tire width direction X, the tire width direction inner ends 52a, 53a Concentration of strain due to overlapping positions is avoided, and failure caused by concentration of strain is avoided.

(2) In the tire 1 according to the embodiment, the tire width direction inner ends 52a of the pair of second ply pieces 52A and the tire width direction inner ends 53a of the pair of third ply pieces 53A are at least Preferably, they are arranged 10 mm apart.

As a result, it is possible to more effectively avoid failures caused by strain concentration due to the tire width direction inner ends 52a and 53a being arranged in the same position in the tire radial direction Y so as to overlap each other.

(3) In the tire 1 according to the embodiment, the belt 40 is provided on the tire radial direction outer side Y1 of the carcass ply 50 in the tread 30, and the tire width direction outer end portion 40B of the belt 40 is connected to the pair of second ply pieces 52A. and the tire width direction inner end portions 53b of the pair of third ply pieces 53A.

As a result, the tire width direction inner end 52b of the second ply piece 52A and the tire width direction inner end 53b of the third ply piece 53A are arranged in a state covered with the tire width direction outer end 40B of the belt 40. Therefore, the separation of the second ply piece 52A and the third ply piece 53A at the tire width direction inner end portions 52b and 53b is suppressed.

(4) In the tire 1 according to the embodiment, the belt 40 has an inner belt 41 and an outer belt 42 arranged outside Y1 in the tire radial direction of the inner belt 41. The end 41A is arranged on the tire width direction outer side X1 from the tire width direction outer end 42A of the outer belt 42, and is arranged between the tire width direction inner end 53a of the pair of third ply pieces 53A and the tire width direction outer end of the outer belt 42. 42A is preferably arranged apart in the tire width direction X.

As a result, the tire width direction inner end 53a of the third ply piece 53A and the tire width direction outer end 42A of the outer belt 42 are aligned in the tire radial direction Y, thereby avoiding failures caused by strain concentration. be done.

(5) In the tire 1 according to the embodiment, the inner ends 53a in the tire width direction of the pair of third ply pieces 53A are separated from the outer ends 42A in the tire width direction of the outer belt 42 to the inner side X2 in the tire width direction by at least 10 mm. are preferably arranged in the same direction.

As a result, the inner end 53a in the tire width direction of the third ply piece 53A and the outer end 42A in the tire width direction of the outer belt 42 overlap each other in the same position in the tire radial direction Y, resulting in concentration of distortion. Failures can be avoided more effectively.

Although specific embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the scope of the present invention. be

For example, in the above embodiment, the second carcass ply 52 is a down ply that is not wound around the bead core 11 . This is preferable from the viewpoint of improving the weight reduction of the tire 1 . However, like the first carcass ply 51 and the third carcass ply 53 , the second carcass ply 52 may also be arranged so as to be wound around the bead core 11 . By extending the folded portion of the second carcass ply 52 to the sidewall 20 in the same manner as the folded portions 51c and 53e of the first carcass ply 51 and the third carcass ply 53, the damage resistance of the sidewall 20 is further improved. can be improved.

1 tire (pneumatic tire)
10 bead 20 sidewall 30 tread 40 belt 40B tire width direction outer end of belt 41 inner belt 41A tire width direction outer end of inner belt 42 outer belt 42A tire width direction outer end of outer belt 50 carcass ply 51 first carcass ply 52 Second carcass ply 52A Second ply piece 52a Tire width direction inner end of second ply piece 52b Tire width direction inner end of second ply piece 53 Third carcass ply 53A Third ply piece 53a Tire of third ply piece Width direction inner end 53b Tire width direction inner end of third ply piece X Tire width direction X1 Tire width direction outer side X2 Tire width direction inner side Y1 Tire radial direction outer side

Claims (5)

a pair of beads;
a pair of sidewalls extending radially outward from each of the pair of beads;
a tread disposed between the pair of sidewalls;
A pneumatic tire comprising a carcass ply extending from the tread to the bead,
The carcass plies include a first carcass ply, a second carcass ply arranged outside the first carcass ply in the tire width direction, and a third carcass ply arranged outside the second carcass ply in the tire width direction. , and
The first carcass ply is arranged continuously in the tire width direction across the pair of beads,
The second carcass ply and the third carcass ply each have a pair of second ply pieces and a pair of third ply pieces divided in the tire width direction,
Each of the pair of second ply pieces and the pair of third ply pieces has a tire width direction inner end that is spaced apart from each other in the tire width direction in the tread,
The tire width direction inner ends of the pair of second ply pieces and the tire width direction inner ends of the pair of third ply pieces are arranged apart in the tire width direction. The tire width direction inner ends of the pair of second ply pieces and the tire width direction inner ends of the pair of third ply pieces are arranged apart from each other by at least 10 mm in the tire width direction. Pneumatic tires as described. A belt is provided outside the carcass ply in the tread in the tire radial direction,
The tire width direction outer end of the belt is arranged so as to overlap the tire width direction inner end of the pair of second ply pieces and the tire width direction inner end of the pair of third ply pieces. 3. The pneumatic tire according to Item 1 or 2. The belt has an inner belt and an outer belt arranged outside the inner belt in the tire radial direction,
The tire width direction outer end of the inner belt is arranged outside the tire width direction outer end of the outer belt in the tire width direction,
The pneumatic tire according to claim 3, wherein the tire width direction inner ends of the pair of third ply pieces and the tire width direction outer ends of the outer belts are spaced apart in the tire width direction. The tire width direction inner end of the pair of third ply pieces according to claim 4, wherein the tire width direction outer end of the outer belt is spaced at least 10 mm inward in the tire width direction. pneumatic tires.

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