Pneumatic tire

Abstract

To provide a pneumatic tire capable of suppressing occurrence of ply cut even in a high-load type passenger car.SOLUTION: A tread 30 includes a belt 31, a carcass ply 50 includes a ply body part 50A extending from the tread 30 inward in a tire axial direction of a pair of beads 10 via a pair of sidewalls 20, and a winding-up part 50B folded back to extend outward in a tire radial direction by being wound around a bead core 11 from the ply body part 50A, and the winding-up part 50B has an overlapping part 50c which overlaps inward in the tire radial direction at an end outward in the tire axial direction of the belt 31. On a half-cross section in the tire axial direction, a ratio L / 130W of a distance L in the tire axial direction between a tip 50b inward in the tire axial direction of the overlapping part 50c and a grounding end 38b of the tread 30 to a grounding half width 130W of the tread 30 in applying 130% load of a maximum load in a tire standard TRA is 5% or more and 20% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having excellent ply cut resistance and suitable for use on passenger cars. [Background technology]

[0002] Conventionally, a pneumatic tire for vehicles has a tire framework called a carcass ply embedded between the left and right beads. A known form of the carcass ply is that both ends in the tire axial direction are wound around the bead core and bead filler constituting the bead from the inside to the outside in the tire axial direction, thereby having a rolled-up portion that extends outward in the tire radial direction on the outside of the bead in the tire axial direction (see Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-169265 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when a tire falls into a depression called a pothole and receives a strong impact while traveling, the sidewall, especially the part close to the tread called the buttress, is significantly distorted and expanded. If the tension caused by the distortion is large, a large tensile stress is applied to the carcass ply near the buttress, and there is a risk that the cords in the carcass ply will break, which is called a ply cut. Since this ply cut can cause the tire to burst, it is necessary to prevent its occurrence. In particular, high-load vehicles, which are heavy, are relatively likely to experience ply cuts.

[0005] Therefore, an object of the present invention is to provide a pneumatic tire that can suppress the occurrence of ply cuts even in a heavy-load passenger vehicle. [Means for solving the problem]

[0006] The pneumatic tire of the present invention is a pneumatic tire including a pair of beads including a bead core and a bead filler extending from the bead core to the tire radial direction outer side, a pair of sidewalls extending from each of the pair of beads to the tire radial direction outer side, a tread disposed between the pair of sidewalls, and a carcass ply that is bridged between the pair of beads and embedded inside the tire, the tread including a belt, and the carcass ply extending from the tread through the pair of sidewalls to the tire axially inner side of the pair of beads. and a rolled-up portion that is folded back and extends radially outward in the tire direction from the ply main body portion and is wound around the bead core from the ply main body portion, the rolled-up portion having an overlap portion that overlaps the radially inward side in the tire direction at the axially outer end of the belt, and in an axial half cross section of the tire, a ratio of L / 130W, which is the tire axial distance L between the axially inner tip of the overlap portion and the ground contact end of the tread to a ground contact half width 130W of the tread at a load of 130% of the maximum load in the TRA tire standard, is 5% or more and 20% or less. Effect of the Invention

[0007] According to the present invention, it is possible to provide a pneumatic tire that can suppress the occurrence of ply cuts even in a heavy-load passenger vehicle. [Brief description of the drawings]

[0008] [Figure 1] 1 is a half cross-sectional view in an axial direction of a pneumatic tire according to an embodiment. FIG. [Diagram 2] FIG. 1 is a simplified diagram showing a state in which a tire falls into a pothole and receives an impact, and is a side view of the tire and the pothole. [Figure 3A] FIG. 13 is a diagram showing a simulation of a state in which the tire of the embodiment falls into a pothole, and is a contour diagram showing the tension distribution caused by distortion. [Figure 3B] FIG. 13 is a diagram showing a simulation of a state in which a tire of a comparative example falls into a pothole, and is a contour diagram showing the tension distribution caused by distortion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing the internal structure of a tire 1, which is a pneumatic tire for a vehicle according to an embodiment, and shows a half cross section in the tire axial direction. This tire 1 is suitable as a tire for passenger cars, and is more suitable as a tire for relatively heavy-load passenger cars such as EVs.

[0010] The cross-sectional view of FIG. 1 is an axial cross-sectional view of a tire 1 mounted on a standard rim (not shown) and inflated to a standard internal pressure in an unloaded state.

[0011] The regular rim is the rim specified by the tire standard, and in the case of the TRA, it is the "Measuring Rim". The regular internal pressure is the air pressure specified by the tire standard, and in the case of the TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". The regular internal pressure is usually 180 kPa for passenger car tires, but is 220 kPa for tires labeled "Extra Load" or "Reinforced". In the case of the TRA, the regular load is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES".

[0012] The internal structure of the tire 1 is basically symmetrical in a cross section in the tire axial direction. Fig. 1 shows a cross section of the right half of the tire 1, and the left half (not shown) has the same structure. In Fig. 1, the symbol S1 indicates the tire equatorial plane. The tire equatorial plane S1 is a plane perpendicular to the tire rotation axis and located at the center in the tire axial direction.

[0013] Here, the tire axial 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, this is illustrated as the tire axial direction X. The tire axially inner side is a direction approaching the tire equatorial plane S1, and is the left side on the paper in Fig. 1. The tire axially outer side is a direction away from the tire equatorial plane S1, and is the right side on the paper in Fig. 1.

[0014] 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 tire radial direction Y. The outer side in the tire radial direction is a direction away from the tire rotation axis, and is the upper side on the paper in Fig. 1. The inner side in the tire radial direction is a direction approaching the tire rotation axis, and is the lower side on the paper in Fig. 1.

[0015] As shown in FIG. 1, the tire 1 includes a pair of beads 10, a pair of sidewalls 20 extending radially outward from each of the pair of beads 10, a tread 30 disposed between the pair of sidewalls 20, a shoulder 40 which is a transition portion from the sidewalls 20 to the tread 30, a carcass ply 50 disposed spanning between the pair of beads 10, and an inner liner 60 disposed on the tire cavity side of the carcass ply 50.

[0016] The pair of beads 10 are disposed on both axial sides of the tire and on the inner ends in the radial direction of the tire. Each bead 10 has a bead core 11, a bead filler 12 extending from the bead core 11 to the outer side in the radial direction of the tire, and a rim strip rubber 13.

[0017] The bead core 11 is an annular member in which a rubber-coated metal bead wire is wound multiple times in the tire circumferential direction. The bead core 11 is a member that serves to fix the tire 1 filled with air to the rim. The bead filler 12 has a tapered shape that decreases in thickness as it extends from the tire radial inner side to the tire radial outer side. 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.

[0018] The rim strip rubber 13 further surrounds the outside of a carcass ply 50 that is provided surrounding the bead core 11 and the bead filler 12. The rim strip rubber 13 comes into contact with the inner surface of a rim on which the tire 1 is mounted.

[0019] The sidewall 20 includes a sidewall rubber 21 disposed axially outward of the carcass ply 50. The sidewall rubber 21 constitutes the circumferentially outer side surface of the tire 1. The sidewall rubber 21 is the portion that bends the most when the tire 1 performs its cushioning function, and flexible rubber having fatigue resistance is usually used for the sidewall rubber 21.

[0020] A rim line 21c protruding axially outward is formed on an inner end 21a in the tire radial direction of the sidewall rubber 21. The rim line 21c is a circular line extending along the tire circumferential direction.

[0021] The tread 30 includes an endless belt 31, a cap ply 34, and a tread rubber 37. The belt 31 is disposed on the outer side of the carcass ply 50 in the tire radial direction. The cap ply 34 is disposed on the outer side of the belt 31 in the tire radial direction. The tread rubber 37 is disposed on the outer side of the cap ply 34 in the tire radial direction.

[0022] The belt 31 is a member that reinforces the tread 30. The belt 31 of the embodiment has a two-layer structure including an inner belt 32 arranged on the outer side of the inner liner 60 in the tire radial direction, and an outer belt 33 arranged on the outer side of the inner belt 32 in the tire radial direction. Both the inner belt 32 and the outer belt 33 have a structure in which a plurality of belt cords such as steel cords are covered with rubber. The inner belt 32 is wider than the outer belt 33. By providing the belt 31, the rigidity of the tire 1 is ensured, and the contact of the tread 30 with the road surface is improved. Note that the belt 31 is not limited to a two-layer structure, and may have a single layer structure, or a three-layer structure or more.

[0023] The cap ply 34 is a member that reinforces the tread 30 together with the belt 31. The cap ply 34 has a structure in which a plurality of organic fiber cords having insulating properties, such as polyamide fiber, are covered with rubber. The cap ply 34 is wider than the belt 31 and covers the entire belt 31 from the tire outer surface side. An end 34a on the outer side of the tire in the tire axial direction of the cap ply 34 is folded toward the tire cavity side to form a double layer, and this end 34a covers the ends 32a, 33a on the outer side of the tire in the tire axial direction of the inner belt 32 and the outer belt 33 from the tire outer surface side. By providing the cap ply 34, it is possible to improve the durability of the tire 1 and reduce road noise during driving. The cap ply 34 is not limited to a single-layer structure as in the embodiment, but may have a two-layer structure or a three-layer structure or more.

[0024] The tread rubber 37 is disposed on the outer side of the cap ply 34 in the tire radial direction. The outer surface of the tread rubber 37 constitutes a tread surface 38 that comes into contact with the road surface. A tread pattern 39 is provided on the tread surface 38. The tread pattern 39 has a plurality of main grooves 80 that extend over the entire circumference of the tire in the tire circumferential direction. The main grooves 80 include a first main groove 81 and a second main groove 83 that are spaced apart in the tire axial direction. An axially outer end 37a of the tread rubber 37 covers an axially outer end 21b of the sidewall rubber. An axially outer end 37a of the tread rubber 37 has a buttress 23a that protrudes axially outward.

[0025] Here, FIG. 1 shows a half contact width 100W of the tread surface 38 at 100% of the maximum load of the tire standard TRA, and a half contact width 130W of the tread surface 38 at 130% of the maximum load of the tire standard TRA, in a tire axial half cross section. Each of the half contact width 100W and the half contact width 130W indicates the tire axial length of the portion where the tread surface 38 comes into contact with the road surface when the corresponding load is applied to the tire 1. FIG. 1 shows the contact edge 38a of the tread surface 38 at the half contact width 100W and the contact edge 38b of the tread surface 38 at the half contact width 130W. That is, the half contact width 100W is the tire axial length between the tire equatorial plane S1 and the contact edge 38a, and the half contact width 130W is the tire axial length between the tire equatorial plane S1 and the contact edge 38b.

[0026] 1, the shoulder 40 is a portion where the sidewall 20 transitions to the tread 30. The shoulder 40 includes an end 37a of the tread rubber 37 on the outer side in the tire axial direction.

[0027] The carcass ply 50 is laid between a pair of beads 10. The carcass ply 50 is embedded inside the tire 1 in a manner that the carcass ply 50 passes between the pair of beads 10, through a pair of sidewalls 20, a pair of shoulders 40, and the tire cavity side of the tread 30. In the tread 30, a belt 31 is disposed on the outer side of the carcass ply 50 in the tire radial direction.

[0028] The carcass ply 50 includes a plurality of ply cords (not shown) that form the framework of the tire 1. The plurality of ply cords extend, for example, along a plane along the tire axial direction, and are arranged side by side in the tire circumferential direction. The ply cords are made of insulating organic fiber cords such as polyester or polyamide. The carcass ply 50 is formed by covering the plurality of ply cords with rubber.

[0029] The carcass ply 50 includes a ply main body 50A and a pair of turned-up portions 50B. The ply main body 50A is a portion that extends from the tread 30 through a pair of shoulders 40 and a pair of sidewalls 20 toward the axially inner side of each of the pair of beads 10. The pair of turned-up portions 50B are portions that are folded back toward the radially outer side of the tire by being wound from the ply main body 50A around each of the pair of bead cores 11, and extend along the sidewalls 20.

[0030] The ply body 50A is disposed on the radially inner side of the belt 31 and the shoulder pad 41 in the tread 30, and on the axially inner side of the sidewall rubber 21 in the sidewall 20. The turned-up portion 50B is wound around the bead core 11 from the axially inner side to the axially outer side, and then extends radially outward along the sidewall 20 and reaches the axially outer end of the tread 30. The part of the turned-up portion 50B that is radially outward of the bead filler 12 is overlapped on the axially outer side of the ply body 50A. The end of the turned-up portion 50B is sandwiched between the axially outer end of the belt 31 and the ply body 50A, and its tip 50b is located axially inward of the axially outer tip 33b of the outer belt 33.

[0031] That is, the end of the rolled-up portion 50B including the tip 50b has an overlapping portion 50c that overlaps the axially outer end of the belt 31 in the tire radial direction. In FIG. 1, the tire axial length of the overlapping portion 50c is indicated by Lc. Also, in FIG. 1, the tire axial distance between the axially inner tip 50b of the overlapping portion 50c of the rolled-up portion 50B and the ground contact end 38b of the half contact width 130W is indicated by L. In the tire 1 of the embodiment, in the tire axial half cross section, the ratio of the distance L to the half contact width 130W of the tread surface 38: L / 130W is preferably 5% or more and 20% or less, more preferably 10% or more and 15% or less.

[0032] The rim strip rubber 13 of the bead 10 described above surrounds the end of the carcass ply 50 on the inner side in the radial direction of the tire, the end winding around the bead core 11 .

[0033] Although the carcass ply 50 in the embodiment has a single layer structure, the carcass ply 50 may have two layers, or three or more layers. When the carcass ply 50 has a single layer structure, it is preferable in that the tire 1 can be made lighter.

[0034] The inner liner 60 covers the inner surface of the ply body portion 50A of the carcass ply 50 between a pair of beads 10 to form the tire cavity surface. The inner liner 60 of the embodiment has a two-layer structure having a first inner liner 61 on the tire cavity side and a second inner liner 62 overlapped on the tire outer surface side of the first inner liner 61. Each of the inner liners 61, 62 is made of air permeability resistant rubber. The inner liner 60 prevents air in the tire cavity from leaking to the outside. The inner liner 60 may have a single-layer structure instead of a two-layer structure. At the tire radial inner part of the bead 10 on the tire axial inner side, the rim strip rubber 13 covers the inner liner 60 to form a part of the tire cavity surface.

[0035] In the tire 1 of the embodiment, a reinforcing rubber layer 65 is provided from the radially outer portion of the sidewall 20 through the shoulder 40 to the axially outer portion of the tread 30. The reinforcing rubber layer 65 is sandwiched between the second inner liner 62 and the ply main body portion 50A of the carcass ply 50.

[0036] Here, the rubber used for the bead filler 12 has a hardness higher than at least the sidewall rubber 21 and the inner liner 60. The hardness of the rubber is a hardness measured by "JIS K6253-3:2012 durometer hardness type A".

[0037] 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. The hardness of the rim strip rubber 13 is more preferably about 1 to 1.6 times the hardness of the sidewall rubber 21. By setting the hardness in this range, a balance between the flexibility of the tire and the rigidity in the vicinity of the bead 10 can be ensured.

[0038] The tire 1 according to the embodiment has the above-mentioned internal structure. According to this tire 1, as described above, in the tire axial half cross section, the ratio L / 130W of the distance L between the axially inner tip 50b of the overlapping portion 50c and the ground contact end 38b of the ground contact half width 130W to the ground contact half width 130W of the tread surface 38 at a load of 130% of the maximum load in the tire standard TRA is 5% or more and 20% or less. Furthermore, within this range, it is more preferable that L / 130W is 10% or more and 15% or less.

[0039] Even if the tire 1 falls into a pothole PH as shown in FIG. 2 and receives an impact while the vehicle equipped with the tire 1 is running, the tire 1 of the embodiment is unlikely to cause a ply cut in the carcass ply 50. When the tire 1 falls into a pothole PH, the tire 1 is subjected to an action that generates a large distortion and expands, particularly in the region (indicated by K in FIG. 2) from the outer end of the belt 31 in the tire axial direction to the vicinity of the buttress 23a corresponding to the position of the outer end of the sidewall 20 in the tire radial direction. Here, in the tire 1 of the embodiment, the end of the turned-up portion 50B of the carcass ply 50 is disposed on the inner side in the tire radial direction of the outer end of the belt 31 in the tire axial direction, and thus the tire has an overlapping portion 50c that overlaps with the belt 31 in the tire radial direction. This increases the strength of the region indicated by K in FIG. 2, and as a result, the expansion of the carcass ply 50 is suppressed, and the occurrence of a ply cut in which the cord of the carcass ply 50 is cut near the buttress 23a is suppressed. That is, the tire 1 of the embodiment is effective as a tire that has been provided with measures against potholes.

[0040] If the L / 130W is less than 5%, the length of the overlapping portion 50c overlapping with the belt 31 becomes small, and there is a possibility that the strength cannot be ensured. In addition, the axially outer end 32b of the inner belt 32, which is the axially outer end of the belt 31, and the end 50b of the overlapping portion 50c become close to each other, so that a space is likely to be generated between the inner belt 32 and the ply body portion 50A of the carcass ply 50. If this space is generated, a problem of air pockets in which air remains during the tire building process is likely to occur. On the other hand, if the L / 130W is more than 20%, the overlapping portion 50c becomes excessively long, which may lead to an increase in weight and thus a deterioration in rolling resistance.

[0041] As described above, the tire 1 of the embodiment is for passenger cars, and is particularly suitable for use with relatively heavy-load vehicles such as EVs. In tires for heavy-load vehicles such as EVs, the greater the load (for example, about 130% of the maximum load), the greater the impact when the tire falls into a pothole, and the higher the possibility of ply cutting. However, when the ratio L / 130W is 5% or more and 20% or less, as in the tire 1 of the embodiment, ply cutting near the buttress 23a is suppressed even for heavy-load vehicles.

[0042] The tire 1 according to the embodiment described above provides the following advantages.

[0043] (1) A tire 1 according to an embodiment includes a pair of beads 10 including a bead core 11 and a bead filler 12 extending radially outward from the bead core 11, a pair of sidewalls 20 extending radially outward from each of the pair of beads 10, a tread 30 disposed between the pair of sidewalls 20, and a carcass ply 50 that is bridged between the pair of beads 10 and embedded inside the tire, the tread 30 including a belt 31, and the carcass ply 50 extending axially inward from the tread 30 through the pair of sidewalls 20 to the pair of beads 10. The ply includes a main body portion 50A, and a rolled-up portion 50B that extends radially outward in the tire direction by being wound around a bead core 11 from the ply main body portion 50A, and the rolled-up portion 50B has an overlapping portion 50c that overlaps the radially inward side in the tire direction at the axially outer end of the belt 31, and in an axial half cross section of the tire, a ratio L / 130W of the tire axial distance L between an axially inner tip 50b of the overlapping portion 50c and a ground contact end 38b of the tread 30 to a ground contact half width 130W of the tread 30 at a load of 130% of the maximum load in the tire standard TRA is 5% or more and 20% or less.

[0044] As a result, even when the tire 1 hits a pothole and receives an impact, the tension distribution near the axially outer end of the belt 31 is made uniform, suppressing expansion of the carcass ply 50 and thereby suppressing the occurrence of ply cuts, in which the cords of the carcass ply 50 are cut near the buttress 23a. This effect is particularly noticeable in heavy load passenger cars.

[0045] (2) In the tire 1 according to the embodiment (1), the ratio L / 130W is preferably 10% or more and 15% or less.

[0046] This makes it possible to suppress the occurrence of ply cuts, and this effect is particularly noticeable in heavy-duty passenger vehicles. (3) The tire 1 according to the above embodiments (1) and (2) is suitable for use on passenger cars.

[0047] In other words, in the tire 1 according to the embodiment, even when subjected to a load of 130%, which is a high load for a passenger vehicle such as an EV, expansion is suppressed because the tension distribution near the axially outer end of the belt 31 is uniform, thereby suppressing the occurrence of ply cuts, in which the cords of the carcass ply 50 are cut near the buttress 23a.

[0048] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and even if modifications and improvements are made within the scope of the present invention, they will still be included in the scope of the present invention.

[0049] The tire 1 in the above embodiment is for passenger cars, but the configuration of this tire 1 can be adopted as a tire for heavy-duty passenger cars such as SUVs and EVs, or for various vehicles such as trucks and buses in addition to passenger cars. EXAMPLES

[0050] Examples will be described below. As shown in Table 1, tires of simulation models of Examples 1 to 3 having the same configuration as the above embodiment were evaluated for each of the characteristics of "ply cut resistance," "RRC (rolling resistance coefficient)," and "defects during manufacturing process." "Ply cut resistance" refers to the difficulty of ply cuts occurring when a tire falls into a pothole and receives impact, and the more difficult this is to occur, the higher the evaluation. "Defects during manufacturing process" refers to the difficulty of the above-mentioned air pocket defect occurring during the manufacturing process, and the more difficult this is to occur, the higher the evaluation.

[0051] For each tire of Examples 1 to 3, the ratio of the tire axial distance L between the axially inner tip 50b of the overlapping portion 50c and the ground contact end 38b of the tread 30 to the ground contact half width 130W of the tread 30 in the above embodiment at a load of 130% of the maximum load of the tire standard TRA in the tire axial half cross section of the tire when mounted on a regular rim of the TRA standard and inflated to the regular internal pressure: L / 130W is 5%, 12%, and 20%, respectively. On the other hand, a tire in which the overlapping portion 50c does not overlap the ground contact half width 130W (L / 130W is 0%) and tires of Comparative Examples 1 and 2 in which L / 130W is 25% were similarly evaluated by a simulation model. Note that, for each evaluation, each value of Example 3 is set to an index of 100, and the others are index evaluations compared to Example 3.

[0052] The evaluation methods for "ply cut resistance," "RRC," and "defects in the manufacturing process" are as follows. Ply cut resistance was calculated from the ply tension when a tire mounted on a vehicle collided with a step, assuming that the tire being evaluated was the tire being evaluated. For RRC, one tire was attached to a drum-type tire testing machine and the rolling resistance coefficient was measured. Defects in the manufacturing process were evaluated relatively based on the percentage of defects occurring in the manufacturing process.

[0053] [Table 1]

[0054] As shown in Table 1, the tire of Comparative Example 1 has a good RRC, but shows worse results than each of the Examples in terms of ply cuttability and manufacturing process defects. It was confirmed that the manufacturing process defect was caused by the axially outer end 32b of the inner belt 32, which is the axially outer end of the belt 31 in the embodiment, becoming close to the end 50b of the overlapping portion 50c, causing air pockets to form between the inner belt 32 and the ply body portion 50A of the carcass ply 50. This shows that the overlapping portion 50c in the embodiment overlaps the half ground contact width 130W of the tread 30 in terms of ply cuttability and manufacturing process defects. On the other hand, Comparative Example 4, in which L / 130W is 25%, has the same ply cuttability and manufacturing process defects as each of the Examples, and these properties do not deteriorate, but the RRC deteriorates due to the weight increase. In contrast, it can be seen that all properties are maintained or improved in Examples 1 to 3. Therefore, it was confirmed that even when subjected to a high load of approximately 130% of the maximum load specified by the TRA standard, as long as the above L / 130W is between 5% and 20%, the characteristics of ply cuttability, RRC (rolling resistance coefficient), and defects in the manufacturing process are all good.

[0055] 3A and 3B are both axial cross sections of a portion of a tire where distortion occurs when the tire falls into a pothole, and are diagrams showing the distribution of tension applied to that portion by simulation. FIG. 3A shows a tire of Example 3, and FIG. 3B shows a tire of Comparative Example 1. In FIG. 3A and FIG. 3B, the strength of tension distribution is shown by black and white shading, with the darker the color, the higher the tension, and the whiter the color, the lower the tension. In FIG. 3A and FIG. 3B, the vicinity of the axially outer end of belt 31 in the embodiment is shown by a two-dot chain ellipse.

[0056] Comparing the tire of Example 3 in Fig. 3A with the tire of Comparative Example 1 in Fig. 3B, the tension applied to the axially outer end of the belt 31 in the embodiment is lower in Example 3 than in Comparative Example 1, and the tension is distributed around the periphery. Therefore, when the tire falls into a pothole, the tension applied to the carcass ply is smaller in Example 3 than in Comparative Example 1, and therefore it is found that ply cuts are less likely to occur in Example 3 than in the Comparative Example. [Explanation of symbols]

[0057] 1...Tire (pneumatic tire) 10...Bead 11...Bead core 12...Bead filler 20…Sidewall 30…Tread 31...Belt 38b…Tread edge 50…Carcass ply 50A…Ply body 50B…Winding section 50b...Tire axially inner end of overlapping portion 50c…Overlapped part

Claims

1. A pair of beads including a bead core and a bead filler extending from the bead core outward in a radial direction of the tire; a pair of sidewalls extending radially outward from each of the pair of beads; a tread disposed between the pair of sidewalls; A carcass ply that is bridged between the pair of beads and embedded inside the tire, The tread includes a belt. The carcass ply includes a ply body portion extending from the tread through the pair of sidewalls toward an inner side of the pair of beads in the tire axial direction, and a turn-up portion that is wound around the bead core from the ply body portion and turns back to extend toward an outer side in the tire radial direction, the rolled-up portion has an overlapping portion that overlaps an inner side in the tire radial direction at an outer end of the belt in the tire axial direction, A pneumatic tire in which, in an axial half cross section, the ratio of the tire axial distance L between the axially inner tip of the overlapping portion and the ground contact end of the tread to the ground contact half width 130W of the tread at a load of 130% of the maximum load in tire standard TRA: L / 130W is 5% or more and 20% or less.

2. The pneumatic tire according to claim 1 , wherein the ratio L / 130W is equal to or greater than 10% and equal to or less than 15%.

3. The pneumatic tire according to claim 1 or 2, which is for a passenger car.

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