Pneumatic tire

Abstract

To secure rigidity in a falling down direction of a bead part while being reduced in weight.SOLUTION: In a bead core 20, metal cords 18 are formed to be piled up in plural rows and are formed so that a length in a stage direction thereof is larger than a length in a row direction thereof. The metal cords 18 are set in two rows or more, except for third stages and thereafter of the metal cords 18 counted from an outer end in a tire radial direction toward inside in the tire radial direction and an innermost end in the tire radial direction. A length dimension L of a bead core 29 is set to be two-fold the maximum width dimension 20 Wmax of the bead core 20 or more. A center G of a figure of the bead core 20 is positioned closer to an inner end in the tire radial direction of the bead core 20 than a central part in a longitudinal direction of the bead core 20. The maximum width part of the bead core 20 is positioned at the second stage and thereafter of the metal cord 18 counted from the inner end in the tire radial direction of the bead core 20 toward outside in the tire radial direction thereof, and the maximum width part of the bead core 20 is positioned at the second stage and thereafter of the metal cord 18 counted from an outer end part in the tire radial direction of the bead core 20 toward inside in the tire radial direction thereof.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to pneumatic tires.

Background Art

[0002] A bead core formed by winding a metal cord is embedded in the bead portion of a pneumatic tire (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a bead core of a pneumatic tire, it is important to ensure the rigidity in the collapsing direction of the bead portion.

[0005] An object of the present invention is to provide a pneumatic tire capable of ensuring the rigidity in the collapsing direction of the bead portion while achieving weight reduction.

Means for Solving the Problems

[0006] The pneumatic tire according to claim 1 includes a pair of bead cores embedded in the bead portion, formed by winding a metal cord in the tire circumferential direction, a carcass ply straddling the pair of bead portions and having a main body portion located between the bead cores and a folded-back portion wound around the bead cores, and a side rubber disposed outside the carcass ply in the tire width direction and forming a tire side portion. The bead core is formed by stacking a plurality of rows in the width direction orthogonal to the center line between the main body portion and the folded-back portion of the carcass and a plurality of rows along the center line, and the length in the step direction is formed to be larger than the length in the column direction. Further, in the bead core, from the third row and later of the metal cord counted from the outer end in the tire radial direction toward the inner end in the tire radial direction and except for the innermost end in the tire radial direction, the metal cord is set to two or more rows. The maximum length dimension of the bead core measured along the center line between the main body portion and the folded-back portion is set to be two times or more the maximum width dimension of the bead core measured in a direction perpendicular to the longitudinal direction of the bead core. The centroid of the bead core when viewed in a cross section perpendicular to the axis of the bead core is located on the inner end side in the tire radial direction of the bead core rather than the central portion in the longitudinal direction of the bead core. The maximum width portion of the bead core is located in the second row and later of the metal cord counted from the inner end in the tire radial direction toward the outer end in the tire radial direction. The maximum width portion of the bead core is located in the second row and later of the metal cord counted from the outer end in the tire radial direction toward the inner end in the tire radial direction.

[0007] The pneumatic tire according to claim 1 has a bead core made of a metal cord embedded in the bead portion and has the following configuration.

[0008] (1) The metal cord is stacked in a plurality of rows in the width direction orthogonal to the center line between the main body portion and the folded-back portion of the carcass and a plurality of rows along the center line, and the length in the step direction is formed to be larger than the length in the column direction.

[0009] (2) In the bead core, from the third row and later of the metal cord counted from the outer end in the tire radial direction toward the inner end in the tire radial direction and except for the innermost end in the tire radial direction, the metal cord is set to two or more rows.。

[0010] (3) The length dimension of the bead core measured along the center line between the main body portion and the folded-back portion of the carcass is set to be 2 times or more the maximum width dimension of the bead core measured in a direction perpendicular to the longitudinal direction of the bead core.

[0011] (4) The centroid of the bead core when viewed in a cross section perpendicular to the axis of the bead core is located on the inner end side in the tire diameter direction rather than the central portion in the longitudinal direction of the bead core.

[0012] (5) The maximum width portion of the bead core is located at the second and subsequent stages of the metal cord when counting from the inner end in the tire diameter direction of the bead core to the outer side in the tire diameter direction.

[0013] (6) The maximum width portion of the bead core is located at the second and subsequent stages of the metal cord when counting from the outer end in the tire diameter direction of the bead core to the inner side in the tire diameter direction. The bead portion in which the bead core having all the configurations of (1) to (6) is embedded can achieve weight reduction while ensuring the collapse rigidity.

[0014] The invention according to claim 2 is the pneumatic tire according to claim 1, wherein the number of arranged strands of the metal cord in the maximum width portion of the bead core is set to be 2 or more and 5 or less.

[0015] In the pneumatic tire according to claim 2, since the number of arranged strands of the metal cord in the maximum width portion of the bead core is set to be 2 or more and 5 or less, it is possible to achieve weight reduction while ensuring the bending rigidity of the bead core.

[0016] The invention according to claim 3 is the pneumatic tire according to claim 1 or claim 2, wherein the centroid of the bead core is located on the center line in the width direction of the bead core.

[0017] In the pneumatic tire according to claim 3, the centroid of the bead core is located on the center line in the width direction of the bead core. ThisAccordingly, it is possible to evenly distribute the tension between the main body portion and the folded-back portion of the carcass ply arranged in the tire width direction of the bead core. Note that, when the bead core has a line-symmetric shape, the center line in the width direction of the bead core can be rephrased as the axis of symmetry.

[0018] The invention according to claim 4 is an inflated tire according to any one of claims 1 to 3, wherein the outermost end in the tire radial direction of the bead core is located on the inner side in the tire radial direction with respect to the outer end in the radial direction of the rim flange of the rim to be mounted.

[0019] In the inflated tire according to claim 4, since the bead core having a high bending rigidity is arranged on the inner side in the rim radial direction with respect to the outermost end in the radial direction of the rim flange, it becomes easier to deform the bead portion on the outer side in the tire radial direction than the bead core along the curved surface of the rim flange. For example, when a large lateral force acts on the inflated tire, the load from the inflated tire can be dispersed and supported by the wide surface of the rim flange.

Advantages of the Invention

[0020] As described above, the inflated tire of the present invention has an excellent effect that it is possible to secure the rigidity in the collapsing direction of the bead portion while achieving weight reduction.

Brief Description of the Drawings

[0021]

Figure 1

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Figure 10

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Figure 12

Mode for Carrying Out the Invention

[0022] An inflated tire 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 shows, as an example, a cross section along the rotation axis of a passenger car inflated tire 10 mounted on a rim 38.

[0023] As shown in FIGS. 1 and 2, the inflated tire 10 has a pair of bead portions 12, a pair of tire side portions 14 each extending radially outward from the pair of bead portions 12, and a tread portion 16 extending from one tire side portion 14 to the other tire side portion 14.

[0024] A bead core 20 formed by winding a metal cord 18 is embedded in each of the pair of bead portions 12. The metal cord 18 of the present embodiment is a steel cord used for the bead core of a general inflated tire, and the outer periphery of the metal cord 18 is rubber-coated (not shown).

[0025] A carcass 22 is moored to a pair of bead cores 20. In the carcass 22 of the present embodiment, the end side of a single carcass ply 24 is folded back from the inside to the outside of the tire around the bead core 20 and locked, and the end of the folded-back portion 24B is in contact with the main body portion 24A. Note that the carcass 22 may have two or more carcass plies 24.

[0026] On the outer side in the tire width direction of the carcass 22, a side rubber layer 14A that forms the tire side portion 14 is disposed.

[0027] On the outer side in the tire radial direction of the main body portion 24A, a belt 28 composed of one or more belt plies 26 is disposed. On the outer side in the tire radial direction of the belt 28, a tread rubber layer 16A that forms the tread portion 16 is disposed.

[0028] Between the main body portion 24A and the folded-back portion 24B, a bead filler 30 extends from the bead core 20 to the outer side in the tire radial direction.

[0029] The bead filler 30 decreases in thickness 30T from the outer end in the tire radial direction of the bead core 20 toward the outer side in the tire radial direction. The maximum thickness dimension 30Tmax of the bead filler 30 is set to be smaller than the maximum width dimension 20Wmax of the bead core 20 described later, and can be formed as the width of the outermost side in the tire radial direction of the bead core 20, in other words, the width of the outermost step in the tire radial direction, or the width of the second step from the outermost side in the tire radial direction to the inner side in the tire radial direction, and in some cases, the width of the third step from the outermost side in the tire radial direction to the inner side in the tire radial direction. The maximum thickness dimension 30Tmax of the bead filler 30 is appropriately changed according to the required performance of the pneumatic tire 10 and the like.

[0030] The bead filler 30 is formed of a rubber harder than the side rubber layer 14A, similar to a conventional general pneumatic tire. Note that the bead filler 30 may be disposed as needed, and as shown in FIG. 3, the bead filler 30 may not be disposed between the main body portion 24A and the folded-back portion 24B.

[0031] In the bead portion 12 of the present embodiment, a rubber chafer 32 is disposed on the outer side in the tire width direction of the folded-back portion 24B. However, the rubber chafer 32 may be disposed as needed. As shown in FIG. 4, the rubber chafer 32 may not be disposed in the bead portion 12. Further, as shown in FIG. 5, another rubber chafer 34 may be further disposed in the bead portion 12. As shown in FIG. 6, a large rubber chafer 36 integrating the rubber chafer 32 and the rubber chafer 34 may be disposed.

[0032] The pneumatic tire 10 of the present embodiment is different from the conventional bead portion in the structure of the bead portion 12, particularly the structure of the bead core 20, as described below.

[0033] (Structure of bead core) As shown in FIG. 2, the bead core 20 of the present embodiment is formed by winding a metal cord 18, for example, a steel cord. Since the pneumatic tire 10 of the present embodiment is for a passenger car, as the steel cord, for example, those having a thickness of 0.8 to 1.6 mm are used.

[0034] The bead core 20 is preferably configured as follows. (1) A plurality of rows of the metal cords 18 are stacked in the width direction orthogonal to the longitudinal direction of the main body portion 24A of the carcass ply 24 and in a plurality of stages along the longitudinal direction of the main body portion 24A, and the length in the stage direction is made larger than the length in the column direction. FIG. 2 shows a bead core 20 having, as an example, 6 stages and 1 to 3 rows. Note that the length in the stage direction of the bead core 20 is the length L of the bead core 20 measured along the center line 22CL between the main body portion 24A and the folded-back portion 24B of the carcass ply 24. The length in the column direction of the bead core 20 is the width dimension of the bead core 20 measured in a direction perpendicular to the center line 22CL.

[0035] (2) Set the length L of the bead core 20 to be 2 times or more the maximum width dimension 20Wmax of the bead core 20. In other words, set the number of stages of the metal cord 18 to be 2 times or more the number of columns of the metal cord 18. Note that in the bead core 20 shown in FIG. 2, the length L is 2 times the maximum width dimension 20Wmax.

[0036] (3) Set the centroid G of the bead core 20 when viewed in a cross-section perpendicular to the axis of the bead core 20 (in other words, a cross-section along the rotation axis of the pneumatic tire 10) to the inner end side in the tire radial direction of the bead core 20 rather than the central portion in the longitudinal direction of the bead core 20 (see FIG. 2).

[0037] (4) Set the maximum width portion (the portion with the maximum width dimension 20Wmax) of the bead core 20 to be the second and subsequent stages of the metal cord 18 counted from the metal cord 18 disposed at the inner end in the tire radial direction of the bead core 20 to the outer side in the tire radial direction.

[0038] (5) Set the maximum width portion of the bead core 20 to be the second and subsequent stages of the metal cord 18 counted from the metal cord 18 disposed at the outer end in the tire radial direction of the bead core 20 to the inner side in the tire radial direction.

[0039] (6) In the bead core 20, set two or more columns of the metal cord 18 from the third and subsequent stages of the metal cord 18 counted from the outer end in the tire radial direction to the inner end in the tire radial direction, and other than the innermost end in the tire radial direction.

[0040] Note that the contribution of the bead core 20 is mainly large for the rigidity in the collapsing direction of the bead portion 12, and the contribution of the bead filler 30 is mainly large for the rigidity in the collapsing direction of the tire side portion 14. Further, when the rubber chafers 32, 34, and 36 are provided, these supplementarily reinforce the rigidity in the collapsing direction. Therefore, the rubber chafers 32, 34, and 36 may be provided as necessary.

[0041] Furthermore, the pneumatic tire 10 can be configured as follows with the bead core 20 and others.

[0042] (7) Set the number of arranged metal cords 18 in the maximum width portion of the bead core 20 to be 2 or more and 5 or less.

[0043] (8) Arrange the centroid G of the bead core 20 on the center line 20CL of the bead core 20.

[0044] (9) Position the outermost end in the tire radial direction of the bead core 20 inside the tire radial direction from the outer end 38P in the radial direction of the rim flange 38A of the rim 38 to be mounted.

[0045] (10) Set the number of arranged metal cords 18 in the maximum width portion of the bead core 20 to be 2 or 3.

[0046] (11) Set the length L30 of the bead filler 30 to be shorter than the length dimension L20 of the bead core 20.

[0047] (12) Set the length L30 of the bead filler 30 to be longer than the length dimension L20 of the bead core 20.

[0048] (13) Set the maximum thickness dimension 30Tmax of the bead filler 30 measured in the direction orthogonal to the main body portion 24A of the carcass 22 to be 1 / 2 or less of the maximum width dimension 20Wmax of the bead core 20.

[0049] (14) Use two or more carcass plies.

[0050] (15) Set the maximum width dimension 20Wmax of the bead core 20 to be larger than the thickness dimension 14G of the tire side portion 14 measured in the direction orthogonal to the main body portion 24A of the carcass 22 in the tire maximum width portion.

[0051] (16) Form the first stage on the innermost side in the tire radial direction of the bead core 20 with one metal cord 18.

[0052] (17) The outermost stage of the radially outermost end of the bead core 20 is formed by a single metal cord 18.

[0053] (18) In the bead core 20, the number of rows of the metal cords 18 gradually decreases from the maximum width portion of the bead core 20 toward the inner side in the tire radial direction.

[0054] (19) In the bead core 20, the number of rows of the metal cords 18 gradually decreases from the maximum width portion of the bead core 20 toward the outer side in the tire radial direction.

[0055] (Function, Effect) Since the bead core 20 of the pneumatic tire 10 of the present embodiment satisfies all the requirements of the above (1) to (6), compared with a conventional pneumatic tire that does not satisfy all the requirements of the above (1) to (6), while achieving weight reduction, it is possible to secure the collapsing rigidity of the bead portion 12.

[0056] As described in the above (6), in the bead core 20, by setting the metal cords 18 after the third row counted from the outer side in the tire radial direction to the inner side in the tire radial direction and other than the innermost end in the tire radial direction to two or more rows, it is possible to realize weight reduction while ensuring the rigidity in the collapsing direction of the bead core 20. For example, if the third row counted from the outer side in the tire radial direction to the inner side in the tire radial direction and the third and fourth rows of the metal cords 18 are set to one row, and the second row counted from the inner side in the tire radial direction to the outer side in the tire radial direction is set to one row, the collapsing rigidity of the bead portion 12 is insufficient. Therefore, in order to ensure the collapsing rigidity of the bead portion 12, the metal cords 18 after the third row counted from the outer side in the tire radial direction to the inner side in the tire radial direction and other than the innermost end in the tire radial direction are set to two or more rows.

[0057] In addition, as described in the above (7), by setting the number of arranged metal cords 18 in the maximum width portion of the bead core 20 to two or more and five or less, weight reduction is achieved compared with the case of six or more.

[0058] As described above in (8), by disposing the centroid G of the bead core 20 on the center line 20CL of the bead core 20, the tension can be evenly borne by the main body portion 24A and the folded-back portion 24B of the carcass ply 24 disposed on the tire width direction side of the bead core 20.

[0059] As described above in (9), by positioning the radially outermost end of the bead core 20 radially inward of the radially outer end 38P of the rim flange 38A of the rim 38 to be mounted, the portion radially outside the bead core 20 is more easily deformed along the curved surface of the rim flange 38A. For example, when a large lateral force acts on the pneumatic tire 10, the load from the pneumatic tire 10 can be dispersed and supported by the wide surface of the rim flange 38A. Further, compared with the case where the radially outermost end of the bead core 20 in the tire radial direction is positioned radially outside the radially outer end 38P of the rim flange 38A, the length L of the bead core 20 is shortened and the weight is reduced.

[0060] As described above in (10), by setting the number of arrays of the metal cords 18 in the maximum width portion of the bead core 20 to two or three, a good balance can be achieved between ensuring the collapse rigidity of the bead core 20 and weight reduction.

[0061] After providing the bead filler 30 between the main body portion 24A and the folded-back portion 24B, as described above in (11), by setting the length L30 of the bead filler 30 to be shorter than the length dimension L20 of the bead core 20, while ensuring the rigidity in the collapsing direction of the bead portion 12 obtained by the configuration of the bead core 20, the rigidity in the collapsing direction of the tire side portion 14 can be lowered. By lowering the rigidity in the collapsing direction of the tire side portion 14, the longitudinal spring constant of the pneumatic tire 10 can be lowered while ensuring the rigidity of the bead portion 12, and the vibration property (riding comfort) can be improved.

[0062] A bead filler 30 is provided between the body portion 24A and the folded-back portion 24B. Then, as described in (11) above, by setting the length L30 of the bead filler 30 to be longer than the length dimension L20 of the bead core 20, while ensuring the rigidity of the bead portion 12 in the falling direction obtained by the configuration of the bead core 20, the rigidity of the tire side portion 14 in the falling direction is also increased compared to the case where the bead filler 30 is not provided, and it becomes possible to improve the handling stability of the vehicle.

[0063] As described in (13) above, by setting the maximum thickness dimension 30Tmax of the bead filler 30 measured in the direction orthogonal to the body portion 24A of the carcass 22 to be 1 / 2 or less of the maximum width dimension 20Wmax of the bead core 20, the volume of the bead filler 30 can be reduced compared to the case where the maximum thickness dimension 30Tmax of the bead filler 30 is not set to be 1 / 2 or less of the maximum width dimension 20Wmax of the bead core 20, and it becomes possible to achieve weight reduction while obtaining the effect of the bead filler 30.

[0064] Note that the carcass 22 may be configured by a plurality of carcass plies 24. When the carcass 22 is configured by a plurality of carcass plies 24, it is common to arrange the ends of the folded-back portions 24B of the respective carcass plies 24 offset in the tire radial direction. By doing so, in the tire side portion 14, the number of overlaps of the folded-back portion 24B can be changed for each radial part, and the control of the tire side portion 14 in the falling direction becomes possible.

[0065] However, when the carcass 22 is configured by a single carcass ply 24 as in the present embodiment, the control of the tire side portion 14 in the falling direction cannot be performed as described above. In the pneumatic tire 10 of the present embodiment, by using a single carcass ply 24, it is possible to reduce the weight compared to the case of using two or more carcass plies 24. By combining with the bead core 20 having the structure of the present embodiment and further with the bead filler 30, it is possible to control the rigidity in the collapsing direction of the tire side portion 14 even when there is only one carcass ply 24. Since the weight of the bead core 20 can be reduced, within the range where weight reduction can be achieved, as in the above (14), two or more carcass plies 24 may be used.

[0066] As in the above (15), by setting the maximum width dimension 20Wmax of the bead core 20 to be larger than the thickness dimension 14G of the tire side portion 14 measured in a direction perpendicular to the main body portion 24A of the carcass 22, the rigidity of the bead core 20 in the collapsing direction can be ensured as compared with the case where the maximum width dimension 20Wmax of the bead core 20 is not set larger than the thickness dimension 14G of the tire side portion 14.

[0067] The bead core 20, like a conventional general bead core, winds the metal cord 18 to form rows and columns from the radially inner side to the outer side. However, in the first round, it has the end of the metal cord 18 and is isolated compared to the circumferentially continuous metal cord 18 in other parts, and its ability to contribute to the bending rigidity of the bead core 20 is low. As in the above (16), by forming the innermost first row of the bead core 20 by winding one metal cord 18 once, the rigidity of the bead core 20 in the collapsing direction can be effectively exerted with the remaining rows and columns.

[0068] As in the above (17), by forming the outermost row at the outermost end of the bead core 20 in the tire radial direction by winding one metal cord 18 once, the main body portion 24A and the folded-back portion 24B of the carcass ply 24 can be smoothly approximated with a minimum step toward the outer side in the tire radial direction. Thereby, when manufacturing the green tire of the pneumatic tire 10, it becomes difficult to entrap air between members, and the occurrence of manufacturing defects can be suppressed.

[0069] As described above in (18), in the bead core 20, by gradually decreasing the number of rows of the metal cords 18 from the maximum width portion of the bead core 20 toward the inner side in the tire radial direction, a large step is not formed on the outer surface of the bead core 20. Thereby, when manufacturing the green tire of the pneumatic tire 10, it becomes difficult to entrap air between members (such as between the bead core 20 and the carcass ply 24), and the occurrence of manufacturing defects can be suppressed.

[0070] As described above in (19), in the bead core 20, by gradually decreasing the number of rows of the metal cords 18 from the maximum width portion of the bead core 20 toward the outer side in the tire radial direction, the main body portion 24A and the folded-back portion 24B of the carcass ply 24 can be gradually brought closer to each other toward the outer side in the tire radial direction. Thereby, a large step is not formed on the outer surface of the bead core 20, and when manufacturing the green tire of the pneumatic tire 10, it becomes difficult to entrap air between members (such as between the bead core 20 and the carcass ply 24), and the occurrence of manufacturing defects can be suppressed.

[0071] [Other Embodiments] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention other than the above.

[0072] The structure of the bead core 20 shown in FIG. 2 is an example of the present invention, and as the bead core 20, for example, the structures shown in FIGS. 7 to 12 can be adopted. The structure of the bead core 20 can be appropriately changed without departing from the gist of the present invention according to the use, type, required performance, etc. of the pneumatic tire 10.

[0073] The pneumatic tire 10 of the above embodiment was for a passenger car, but the present invention is not limited to passenger cars, and can also be applied to pneumatic tires other than passenger cars, for example, pneumatic tires for buses, trucks, light trucks, motorcycles, etc. Further, the present invention is not limited to ordinary pneumatic tires, and can also be applied to run-flat tires.

[0074] The thickness of the metal cord 18 in the bead core 20 of the above-described embodiment is the thickness when the pneumatic tire 10 is for a passenger car, and the thickness of the metal cord 18 is appropriately changed for pneumatic tires for other uses.

Explanation of reference numerals

[0075] 10…Pneumatic tire, 12…Bead portion, 14…Tire side portion, 14A…Side rubber layer, 18…Metal cord, 20…Bead core, 22…Carcass 22, 24…Carcass ply 24, 24A…Body portion, 24B…Turn-back portion, 20CL…Center line, G…Geometric center, 38…Rim, 38A…Rim flange, 38P…Radial outer end of the rim flange

Claims

1. A pair of bead cores embedded in a bead portion, formed by winding a metal cord in the tire circumferential direction, A carcass ply straddling the pair of bead portions, having a main body portion positioned between the bead cores and a folded-back portion wound around the bead cores, A side rubber disposed outside the carcass ply in the tire width direction, forming a tire side portion, Comprising, The bead core is formed by stacking the metal cords in multiple rows in the width direction orthogonal to the center line between the main body portion and the folded-back portion, and in multiple rows along the center line, and the length in the step direction is formed to be larger than the length in the column direction, Furthermore, in the bead core, from the third row and subsequent rows of the metal cords counted from the outer end in the tire radial direction toward the inner side in the tire radial direction, and except for the innermost end in the tire radial direction, the metal cords are set in two or more rows, The maximum length dimension of the bead core measured along the center line between the main body portion and the folded-back portion is set to be two times or more the maximum width dimension of the bead core measured in a direction perpendicular to the longitudinal direction of the bead core, When viewed in a cross section perpendicular to the axis of the bead core, the centroid of the bead core is located on the inner side in the tire radial direction of the longitudinal center portion of the bead core, The maximum width portion of the bead core is located in the second row and subsequent rows of the metal cords counted from the inner end in the tire radial direction toward the outer side in the tire radial direction, The maximum width portion of the bead core is located in the second row and subsequent rows of the metal cords counted from the outer end in the tire radial direction toward the inner side in the tire radial direction, The innermost first row of the bead core in the tire radial direction is formed by winding one metal cord once, A pneumatic tire.

2. The number of arranged metal cords in the maximum width portion of the bead core is set to be 2 or more and 5 or less, The pneumatic tire according to Claim 1.

3. The number of arranged metal cords in the maximum width portion of the bead core is set to be 2 or 3, The pneumatic tire according to Claim 1.

4. The centroid of the bead core is located on the center line in the width direction of the bead core, The pneumatic tire according to any one of Claims 1 to 3.

5. The outermost end in the tire radial direction of the bead core is located on the inner side in the tire radial direction than the outer end in the radial direction of the rim flange of the rim to be mounted, The pneumatic tire according to any one of Claims 1 to 4.

6. Furthermore, it includes a bead filler provided between the main body portion and the folded-back portion. The maximum thickness dimension of the bead filler is the width of the outermost step of the bead core in the tire radial direction, the width of the second step from the outermost side in the tire radial direction to the inner side in the tire radial direction, or the width of the third step from the outermost side in the tire radial direction to the inner side in the tire radial direction. The pneumatic tire according to any one of claims 1 to 5.

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