pneumatic tires

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

[Technical Field]

[0001] The present invention relates to a pneumatic tire. [Background technology]

[0002] In passenger vehicle tires, the resistance of sidewalls to external damage when driving on rough roads is an issue. Ensuring the resistance of sidewalls to external damage is particularly important for heavy-duty tires mounted on light trucks and the like.

[0003] Conventionally, in order to ensure the resistance of the sidewall to external damage, the number of carcass plies arranged in the sidewall has been increased (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-152380 Summary of the Invention [Problem to be solved by the invention]

[0005] Increasing the number of carcass plies improves the strength of the sidewall and ensures resistance to external damage, but it also increases the tire weight, which increases rolling resistance. Therefore, it is desirable to reduce the tire weight while improving the sidewall strength.

[0006] An object of the present invention is to provide a pneumatic tire that can improve the external damage resistance of the sidewall while reducing the rolling resistance by reducing the tire weight. [Means for solving the problem]

[0007] The pneumatic tire of the present invention is a pneumatic tire including 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 a carcass ply extending from the tread to the beads, wherein the carcass ply includes a first carcass ply, a second carcass ply disposed on the tire width direction outer side of the first carcass ply, and a third carcass ply disposed on the tire width direction outer side of the second carcass ply, the first carcass ply being disposed continuously in the tire width direction across the pair of beads, the second carcass ply and the third carcass ply having a pair of second ply pieces and a pair of third ply pieces each divided in the tire width direction, the pair of second ply pieces and the pair of third ply pieces each having tire width direction inner ends disposed spaced apart from each other in the tire width direction in the tread, and 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 being disposed apart from each other in the tire width direction. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a pneumatic tire that can improve the external damage resistance of the sidewall while reducing the rolling resistance by reducing the tire weight. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view in the tire width direction of a pneumatic tire according to an embodiment. [Figure 2] FIG. 2 is an enlarged view of a portion of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment will be described with reference to the drawings. Fig. 1 shows a cross section in the tire width direction of a tire 1, which is a pneumatic tire according to the embodiment. Fig. 2 is an enlarged view of a part of Fig. 1, and is a cross section showing a portion from a tread 30 (described later) to a bead 10 on the vehicle outer side D1.

[0011] The tire 1 according to the embodiment is, for example, a pneumatic tire for a passenger car. The tire 1 according to the embodiment can be used for various vehicles such as a light truck, a truck, a bus, etc. in addition to passenger cars.

[0012] The structure of the tire 1 is symmetrical in a cross section in the tire width direction. In Fig. 1, the symbol S1 denotes the tire equatorial plane. The tire equatorial plane S1 is a plane that is perpendicular to the tire rotation axis (tire meridian) and is located at the center in the tire width direction.

[0013] The cross-sectional view in Figure 1 shows the tire 1 mounted on a standard rim and inflated to a standard internal pressure under no load. The standard rim refers to a standard rim established by JATMA for a tire size. The standard internal pressure is, for example, 180 kPa when the tire 1 is for a passenger car.

[0014] Here, the tire width direction is a direction parallel to the tire rotation axis and is the left-right direction on the paper in FIG. 1. In FIG. 1, it is illustrated as the tire width direction X. X1 is the outer side in the tire width direction, and X2 is the inner side in the tire width direction. The outer side X1 in the tire width direction is a direction away from the tire equatorial plane S1, and is the left and right sides on the paper in FIG. 1. The inner side X2 in the tire width direction is a direction approaching the tire equatorial plane S1, and is the center side on the paper in FIG. 1.

[0015] The tire radial direction is a direction perpendicular to the tire rotation axis and is the up-down direction on the paper in FIG. 1. In FIG. 1, this is illustrated as the tire radial direction Y. Y1 is the outer side in the tire radial direction, and Y2 is the inner side in the tire radial direction. The outer side Y1 in the tire radial direction is the direction away from the tire rotation axis and is the upper side on the paper in FIG. 1. The inner side Y2 in the tire radial direction is the direction approaching the tire rotation axis and is the lower side on the paper in FIG. 1.

[0016] 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 from each of the pair of beads 10 toward the tire radially outer side Y1, a tread 30 disposed between the pair of sidewalls 20, a belt 40 disposed on the tread 30, a carcass ply 50 extending from the tread 30 to the pair of beads 10, and an inner liner 60 disposed on the tire cavity side of the carcass ply 50. The tire 1 has a symmetrical structure in the tire width direction X with respect to the tire equatorial plane S1.

[0017] The bead 10 includes a bead core 11, a bead filler 12 extending from the bead core 11 to the outer side Y1 in the tire radial direction, and a rim strip rubber 13.

[0018] The bead core 11 is an annular member in which a rubber-coated metal bead wire is wound multiple times in the circumferential direction of the tire. The bead core 11 is a member that serves to fix the tire 1 filled with air to the rim.

[0019] 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 as it extends from the tire radially inner side Y2 to the tire radially outer end 12a.

[0020] 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 that is harder than the surrounding rubber members.

[0021] As shown in FIG. 1, the rim strip rubber 13 further surrounds the outside of the carcass ply 50, which is provided surrounding the bead core 11 and bead filler 12. The rim strip rubber 13 comes into contact with the inside portion of the rim on which the tire 1 is mounted. An apex 13a extending in the tire circumferential direction is formed on the outer surface of the rim strip rubber 13 on the outer side X1 in the tire width direction. The apex 13a of the rim strip rubber 13 constitutes a rim protector 14 that protects the rim from external damage. The rim protector 14 is continuous in an annular shape in the tire circumferential direction.

[0022] The sidewall 20 includes a sidewall rubber 21 arranged on the outer side X1 in the tire width direction of the carcass ply 50. The sidewall rubber 21 forms the outer wall surface of the tire 1. The sidewall rubber 21 is the part that bends the most when the tire 1 performs its cushioning function, and typically uses flexible rubber that is fatigue-resistant. An end portion of the sidewall rubber 21 on the inner side Y2 in the tire radial direction covers an end portion of the rim strip rubber 13 on the outer side Y1 in the tire radial direction.

[0023] The tread 30 includes a 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 outer side Y1 in the tire radial direction of the inner liner 60. The cap ply 45 is arranged on the outer side Y1 in the tire radial direction of the belt 40. The tread rubber 31 is arranged on the outer side Y1 in the tire radial direction of the cap ply 45.

[0024] The belt 40 is a member that reinforces the tread 30. The belt 40 of this 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. 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 outer end portions 40B on the outer side X1 in the tire width direction, where the inner belt 41 and the outer belt 42 overlap.

[0025] In the belt 40, the inner belt 41 is wider than the outer belt 42. Therefore, as shown in Fig. 2, an outer end 41A in the tire width direction, which is the tip of the inner belt 41 on the outer side X1 in the tire width direction, is positioned further toward the outer side X1 in the tire width direction than an outer end 42A in the tire width direction, which is the tip of the outer belt 42 on the outer side X1 in the tire width direction. Providing the belt 40 ensures the rigidity of the tire 1 and improves the contact of the tread 30 with the road surface.

[0026] The cap ply 45 is a member that reinforces the tread 30 together with the belt 40. The cap ply 45 has a structure in which a plurality of insulating organic fiber cords, such as polyamide fiber cords, are covered with rubber.

[0027] 2, the tire width direction outer end 45B of the cap ply 45 is double-folded by being folded inward from the outer side Y1 in the tire radial direction. A tire width direction outer end 45A, which is the tip of the cap ply 45 on the outer side X1 in the tire width direction, is positioned more outer in the tire width direction X1 than the tire width direction outer end 41A of the inner belt 41. The tire width direction outer end 45B of the cap ply 45 covers and is in close contact with 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.

[0028] Although the cap ply 45 in the embodiment is a single layer, it may be a structure of two or more layers. By providing the cap ply 45, it is possible to improve durability and reduce road noise during driving.

[0029] As shown in FIG. 1, the tread rubber 31 is disposed on the outer side Y1 in the tire radial direction of the cap ply 45. The tread rubber 31 is a member that forms a tread surface 31a that comes into contact with the road surface during travel. A tread pattern 32 consisting of, for example, a plurality of grooves is provided on the tread surface 31a of the tread rubber 31. As shown in FIG. 2, an outer end 31B in the tire width direction of the tread rubber 31 bends toward the inner side Y2 in the tire radial direction beyond an outer end 45A in the tire width direction of the cap ply 45 and comes into contact with the carcass ply 50. As shown in FIG. 1, the outer end 31B in the tire width direction of the tread rubber 31 is covered by an outer end 21B in the tire radial direction of the sidewall rubber 21.

[0030] The carcass ply 50 constitutes a ply that forms the framework of the tire 1. As shown in FIG. 1 , the carcass ply 50 of the embodiment has a three-layer structure consisting of, in order from the tire cavity side, a first carcass ply 51, a second carcass ply 52, and a third carcass ply 53. The first carcass ply 51, the second carcass ply 52, and the third carcass ply 53 each include a plurality of carcass cords (not shown) that form the framework 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. The carcass cords are made of insulating organic fiber cords such as polyester or polyamide. The first carcass ply 51, the second carcass ply 52, and the third carcass ply 53 are each formed by covering a plurality of carcass cords with rubber. The tire 1 has the carcass ply 50 with a three-layer structure, which improves the strength of the sidewall 20 and the external damage resistance of the tire 1.

[0031] The first carcass ply 51 is disposed closest to the tire inner surface of the carcass ply 50 and is disposed in contact with the tire outer surface side of the inner liner 60. The first carcass ply 51 is formed continuously in the tire width direction X across a pair of beads 10 without interruption. That is, as shown in Fig. 2, the first carcass ply 51 has a first carcass ply main body portion 51a extending from the tread 30 at the center in the tire width direction to each of the pair of sidewalls 20 and further extending to the tire width direction inner side X2 of the bead core 11, a bent portion 51b wound around the bead core 11 from the first carcass ply main body portion 51a and bent, a turned-up portion 51c turned back from the bent portion 51b to the tire radially outer side Y1, and a turned-up end 51d which is the tip of the turned-up portion 51c on the tire radially outer side Y1.

[0032] The first carcass ply main body portion 51a, the bent portion 51b, and the turned-up portion 51c are continuous. An end portion on the inner side Y2 in the tire radial direction of the first carcass ply main body portion 51a is arranged on the inner side X2 in the tire width direction of the bead core 11 and the bead filler 12. The turned-up portion 51c is arranged on the outer side X1 in the tire width direction of the bead core 11 and the bead filler 12. The bent portion 51b is arranged on the inner side Y2 in the tire radial direction of the bead core 11, and constitutes the innermost portion of the first carcass ply 51 in the tire radial direction Y. The turned-up portion 51c extends to the vicinity of the tire maximum width position 20W. The turned-up end 51d is arranged near the tire maximum width position 20W.

[0033] The second carcass ply 52 is disposed on the tire outer surface side of the first carcass ply 51, and the third carcass ply 53 is disposed on the tire outer surface side of the second carcass ply 52. ​​The second carcass ply 52 and the third carcass ply 53 each have a discontinuous cutout portion in the center in the tire width direction, and are configured to be divided into two parts in the tire width direction X with this cutout portion sandwiched between them. Even though the tire 1 has a carcass ply 50 with a three-layer structure, the second carcass ply 52 and the third carcass ply 53 have the cutout portions, which reduces the tire weight and rolling resistance.

[0034] The second carcass ply 52 includes a pair of second ply pieces 52A divided in the tire width direction X. The second carcass ply 52 has a first cutout portion 52H that is discontinuous in the tire width direction center of the tread 30. The pair of second ply pieces 52A are embedded in the tire 1 in such a manner that they are disposed on both sides in the tire width direction X with the first cutout portion 52H sandwiched therebetween.

[0035] 2, the second ply piece 52A has tire widthwise inner ends 52a that are at the tip end on the first hollowed-out portion 52H side and are spaced apart and opposed to each other in the tire width direction X. The tire widthwise inner end 52a of the second ply piece 52A is disposed at an end on the tire widthwise outer side X1 of the tread 30. The second ply piece 52A has a tire widthwise inner end portion 52b that includes the tire widthwise inner end 52a, on the tire widthwise inner side X2.

[0036] 2, the second ply piece 52A has a second ply piece main body portion 52c that extends from an inner end 52a in the tire width direction to the sidewall 20 and further extends to the inner side X2 of the bead filler 12 in the bead 10 in the tire width direction. The second ply piece 52A is a down ply and extends partway into the bead filler 12. A tire radially inner end 52d, which is the tip of the second ply piece main body portion 52c on the innermost side Y2 in the tire radial direction, does not reach the bead core 11. The tire radially inner end 52d of the second ply piece main body portion 52c is located on the inner side X2 of the bead filler 12 in the tire width direction.

[0037] Since no hollowed-out portion is formed in the first carcass ply 51, the inner end 52a in the tire width direction of the second carcass ply 52 is disposed on the tire outer surface side of the first carcass ply 51 in the tread 30 and is not in direct contact with the inner liner 60. Therefore, interference between the inner end 52a in the tire width direction of the second carcass ply 52 and the inner liner 60, which has lower strength than the belt 40, can be avoided.

[0038] The third carcass ply 53 includes a pair of third ply pieces 53A divided in the tire width direction X. The third carcass ply 53 has a second cutout portion 53H that is discontinuous in a center portion in the tire width direction of the tread 30. The pair of third ply pieces 53A are embedded in the tire 1 in such a manner that they are disposed on both sides in the tire width direction X with the second cutout portion 53H sandwiched therebetween.

[0039] 2, the third ply piece 53A has tire widthwise inner ends 53a that are at the tip end on the second cutout portion 53H side and are spaced apart and opposed to each other in the tire width direction X. The tire widthwise inner end 53a of the third ply piece 53A is disposed at an end on the tire widthwise outer side X1 of the tread 30. The third ply piece 53A has a tire widthwise inner end portion 53b that includes the tire widthwise inner end 53a, on the tire widthwise inner side X2.

[0040] The third ply piece 53A has a third ply piece main body portion 53c extending from an inner end 53a in the tire width direction to the sidewall 20 and further extending to the inner side X2 in the tire width direction of the bead filler 12 in the bead 10, a bent portion 53d that wraps around the bead core 11 and bends from the third ply piece main body portion 53c, a folded portion 53e that is folded back from the bent portion 53d to the outer side Y1 in the tire radial direction, and a folded end 53f that is the tip of the folded portion 53e on the outer side Y1 in the tire radial direction.

[0041] The third ply piece main body portion 53c, the bent portion 53d, and the turned-up 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. ​​A tire radially inner end 52d, which is an end portion on the tire radially inner side Y2 of the second ply piece main body portion 52c, is sandwiched between the first carcass ply main body portion 51a and the third ply piece main body portion 53c on the tire widthwise inner side X2 of the bead filler 12. The bent portion 53d of the third carcass ply 53 is sandwiched between the bead core 11 and the bent portion 51b of the first carcass ply 51. The bent portion 53d of the third carcass ply 53 constitutes the innermost portion of the third carcass ply 53 in the tire radial direction Y. The turned-up portion 53e of the third carcass ply 53 is sandwiched between the bead core 11 and the bead filler 12 and the turned-up portion 51c of the first carcass ply 51. The turned-up portion 53e of the third carcass ply 53 extends to a position Y1 radially outward of the tire maximum width position 20W. A turned-up end 53f of the third carcass ply 53 is located further outward in the tire radial direction than the position of the turned-up end 51d of the first carcass ply 51, and is located further outward in the tire radial direction than the tire maximum width position 20W.

[0042] The inner liner 60 is disposed on the inner surface of the tire between a pair of beads 10. The inner liner 60 covers the inner surfaces of the belt 40 and the first carcass ply 51 in the tread 30 region. The inner liner 60 also covers the inner surface of the first carcass ply 51 in the sidewall 20 region. Furthermore, the inner liner 60 covers the inner surface of the first carcass ply 51 in a region on the outer side Y1 of the bead 10 in the tire radial direction, and covers the rim strip rubber 13 in a region on the inner side Y2 of the bead 10 in the tire radial direction.

[0043] The inner liner 60 is made of air-permeable rubber and prevents air from leaking out of the tire cavity.

[0044] The rubber used for the bead filler 12 has a hardness higher than that of at least the sidewall rubber 21 and the inner liner 60. The hardness of the rubber is a value (durometer hardness) measured with a type A durometer in an atmosphere of 23°C in accordance with JIS K6253.

[0045] For example, when the hardness of the sidewall rubber 21 is used as a reference, it is preferable that the hardness of the bead filler 12 be about 1.2 to 2.3 times that of the sidewall rubber 21. It is more preferable that the hardness of the rim strip rubber 13 be about 1 to 1.6 times that of the sidewall rubber 21. By using such hardness, it is possible to ensure a balance between the flexibility of the tire and the rigidity in the vicinity of the bead 10.

[0046] 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 spaced apart in the tire width direction X. Either the tire width direction inner end 52a of the second carcass ply 52 or the tire width direction inner end 53a of the third carcass ply 53 may be located on the tire width direction outer side X1, but the tire width direction inner end 53a of the third carcass ply 53 shown in the embodiment is located on the tire width direction outer side X1 by a distance L1 from the tire width direction inner end 52a of the second carcass ply 52. ​​The tire width direction inner end 53a of the third carcass ply 53 is located between the inner belt 41 and the second carcass ply 52 and is not in direct contact with the inner liner 60.

[0047] This avoids failures caused by strain concentration due to the alignment of the tire width direction inner ends 52a, 53a of the second carcass ply 52 and the third carcass ply 53. From the viewpoint of more effectively avoiding failures caused by strain concentration, the distance L1 is preferably at least 10 mm.

[0048] 2, the tire width direction outer end 40B of the belt 40, 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 to overlap in the tire radial 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 covered by the tire width direction outer end 41B of the inner belt 41 and the tire width direction outer end 42B of the outer belt 42. This prevents the second ply piece 52A and the third ply piece 53A from peeling off on the tire width direction inner end portions 52b, 53b sides.

[0049] 2, an inner end 53a in the tire width direction of the third ply piece 53A and an outer end 42A in the tire width direction of the outer belt 42 of the belt 40 are spaced apart in the tire width direction X. In the embodiment, the inner end 53a in the tire width direction of the third ply piece 53A is located a distance L2 inward in the tire width direction X2 from the outer end 42A in the tire width direction of the outer belt 42, which is narrower than the inner belt 41.

[0050] This avoids failures caused by strain concentration due to 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 being aligned in the tire radial direction Y. From the viewpoint of more effectively avoiding failures caused by strain concentration, the distance L2 is preferably at least 10 mm, and from the viewpoint of weight reduction, it is more preferably 10 mm or more and 50 mm or less.

[0051] The tire 1 of the embodiment described above provides the following effects.

[0052] (1) A tire 1 according to an embodiment is a pneumatic tire 1 including a pair of beads 10, a pair of sidewalls 20 extending from each of the pair of beads 10 to the tire radially outer side Y1, a tread 30 disposed between the pair of sidewalls 20, and a carcass ply 50 extending from the tread 30 to the bead 10, wherein the carcass ply 50 includes a first carcass ply 51, a second carcass ply 52 disposed on the tire width direction outer side X1 of the first carcass ply 51, and a third carcass ply 53 disposed on the tire width direction outer side X1 of the second carcass ply 52, and the first carcass ply The second carcass ply 52 and the third carcass ply 53 each have a pair of second ply pieces 52A and a pair of third ply pieces 53A that are divided in the tire width direction X, and 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 spaced apart from each other in the tire width direction X in the tread 30, and 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 arranged spaced apart from each other in the tire width direction X.

[0053] This improves the external damage resistance of the sidewall 20 and reduces rolling resistance by reducing the weight of the tire 1. Since the tire width direction inner ends 52a, 53a of the second ply piece 52A and the third ply piece 53A are spaced apart in the tire width direction X, concentration of strain caused by the tire width direction inner ends 52a, 53a being arranged overlapping at the same position in the tire radial direction Y is avoided, and failures caused by concentration of strain are avoided.

[0054] (2) In the tire 1 according to the embodiment, it is preferable that 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 spaced apart by at least 10 mm in the tire width direction X.

[0055] This makes it possible to more effectively avoid failures that occur due to concentration of strain caused by the inner ends 52a, 53a in the tire width direction being arranged overlapping at the same position in the tire radial direction Y.

[0056] (3) In the tire 1 according to the embodiment, it is preferable that the tread 30 has a belt 40 on the tire radially outer side Y1 of the carcass ply 50, and that the tire widthwise outer end 40B of the belt 40 is arranged so as to overlap the tire widthwise inner end 52b of the pair of second ply pieces 52A and the tire widthwise inner end 53b of the pair of third ply pieces 53A.

[0057] As a result, 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 positioned in a state where they are covered by the tire width direction outer end portion 40B of the belt 40, thereby preventing the second ply piece 52A and the third ply piece 53A from peeling off on the tire width direction inner end portion 52b, 53b side.

[0058] (4) In the tire 1 according to the embodiment, the belt 40 has an inner belt 41 and an outer belt 42 arranged radially outward Y1 of the inner belt 41, and the tire width direction outer end 41A of the inner belt 41 is arranged radially outward X1 of the tire width direction outer end 42A of the outer belt 42, and it is preferable that the tire width direction inner ends 53a of the pair of third ply pieces 53A and the tire width direction outer ends 42A of the outer belt 42 are spaced apart in the tire width direction X.

[0059] This avoids failures caused by concentration of strain due to 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 being aligned in the tire radial direction Y.

[0060] (5) In the tire 1 according to the embodiment, it is preferable that the tire width direction inner ends 53a of the pair of third ply pieces 53A are positioned at least 10 mm away from the tire width direction outer ends 42A of the outer belt 42 on the inner side X2 in the tire width direction.

[0061] This makes it possible to more effectively avoid failures caused by the concentration of strain due to 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 being overlapped at the same position in the tire radial direction Y.

[0062] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and modifications and improvements made within the scope of the present invention are also included in the scope of the present invention.

[0063] For example, in the above embodiment, the second carcass ply 52 is a down ply that is not wrapped around the bead core 11. This is preferable from the viewpoint of improving the weight reduction of the tire 1. However, the second carcass ply 52 may also be arranged so as to be wrapped around the bead core 11, similar to the first carcass ply 51 and the third carcass ply 53. By extending the turned-up portion of the second carcass ply 52 to the sidewall 20, similar to the turned-up portions 51c, 53e of the first carcass ply 51 and the third carcass ply 53, the external damage resistance of the sidewall 20 can be further improved. [Explanation of symbols]

[0064] 1. Tires (pneumatic tires) 10 beads 20 Sidewall 30 tread 40 Belt 40B Belt outer end in tire width direction 41 Inner belt 41A Outer end of inner belt in tire width direction 42 Outer belt 42A Outer end of outer belt in tire width direction 50 carcass ply 51 First carcass ply 52 Second carcass ply 52A Second ply piece 52a Inner end of second ply piece in the tire width direction 52b: inner end portion in the tire width direction of the second ply piece 53 3rd carcass ply 53A Third ply piece 53a Inner end of third ply piece in the tire width direction 53b: inner end portion in the tire width direction of the third ply piece X Tire width direction X1 Outer side of tire width X2 Tire width direction inner side Y1 Tire radial outer side

Claims

1. a pair of beads; a pair of sidewalls extending radially outward from the pair of beads, respectively; a tread disposed between the pair of sidewalls; A pneumatic tire comprising: a carcass ply extending from the tread to the bead; The pair of beads each have a bead core, the carcass ply includes a first carcass ply, a second carcass ply disposed on the outer side of the first carcass ply in the tire width direction, and a third carcass ply disposed on the outer side of the second carcass ply in the tire width direction, The first carcass ply is disposed 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 that are divided in the tire width direction, the pair of second ply pieces and the pair of third ply pieces each have inner ends in the tire width direction that are spaced apart from each other in the tire width direction in the tread, Inner ends of the pair of second ply pieces in the tire width direction and inner ends of the pair of third ply pieces in the tire width direction are spaced apart in the tire width direction, The third ply piece has a bending portion that is bent while being wrapped around the bead core.

2. 2. The pneumatic tire according to claim 1, wherein inner ends in the tire width direction of the pair of second ply pieces and inner ends in the tire width direction of the pair of third ply pieces are spaced apart by at least 10 mm in the tire width direction.

3. A belt is provided on the tire radial direction outer side of the carcass ply in the tread, 3. The pneumatic tire according to claim 1, wherein an outer end portion of the belt in the tire width direction is arranged to overlap an inner end portion of the pair of second ply pieces in the tire width direction and an inner end portion of the pair of third ply pieces in the tire width direction.

4. The belt includes an inner belt and an outer belt disposed radially outward of the inner belt, an outer end of the inner belt in the tire width direction is disposed more outer in the tire width direction than an outer end of the outer belt in the tire width direction, The pneumatic tire according to claim 3 , wherein inner ends of the pair of third ply pieces in the tire width direction and outer ends of the outer belts in the tire width direction are spaced apart from each other in the tire width direction.

5. The pneumatic tire according to claim 4 , wherein inner ends in the tire width direction of the pair of third ply pieces are disposed at least 10 mm apart on the inner side in the tire width direction from the outer ends in the tire width direction of the outer belts.

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