RU2817435C2 - Pneumatic tire - Google Patents

Abstract

FIELD: vehicles.

SUBSTANCE: invention relates to automotive industry. Pneumatic tire (1) includes bead cores (21) formed by winding bead wires (28) in a ring and having a shape in the meridian cross section of the tire, formed with a polygonal cross section; carcass (6) extending between bead sections (20) on both sides in transverse direction of the tire. Carcass (6) passes through inner side of bead core (21) in tire radial direction from bead core (21) inner side in tire transverse direction and is wrapped in reverse side to outer side in tire transverse direction in bead section (20). Carcass (6) is formed by coating carcass cord (6c) with covering rubber (6d). Inner layer (50) reinforced with organic fibre is wound around core (21) of bead and formed by covering cord (51) of organic fibre with covering rubber (52). Rubber reinforcing layer (60) is located between inner reinforced organic fibre layer (50) and carcass (6) so that it covers at least top on innermost side of bead core (21) in tire transverse direction. Shortest distance between bead wire (28) and carcass cord (6c) is 3 mm or more.

EFFECT: higher wear resistance of tire bead section.

15 cl, 20 dwg

Description

Technical field

The present invention relates to a pneumatic tire.

State of the art

A pneumatic tire is mounted on a wheel rim by placing a bead section with a bead core corresponding to a ring element containing a plurality of bead wires united into a bundle onto the rim of the wheel rim. The bead portion is a portion directly mounted on the wheel rim when mounting the pneumatic tire onto the wheel rim, and thus is an important portion for ensuring the performance of the pneumatic tire. In some known pneumatic tires, various adaptations are made to portions of the bead to achieve the desired characteristics.

For example, in the pneumatic tire described in JP 5981136 B, a rubber web layer is provided that extends continuously from the bottom of the belt layer to the inner surface of the bead filler side through the underside of the bead portion. The hardness of the rubber layer of the rubber sheet is differentiated depending on the zone to reduce the noise caused by the tire rolling on the road. Moreover, in the pneumatic heavy-duty vehicle tire disclosed in JP 4934178 B, the surface of the bead core substrate is surrounded by a wrapping material in which a plurality of organic fiber cords are covered with a top protective layer of rubber, and a shortest distance between steel wires on the innermost side of the core substrate the bead in the axial direction of the tire and the carcass cord is set to 1.8-3.0 mm, which prevents rupture of the carcass cord and increases the wear resistance of the bead section. In addition, the pneumatic tire described in JP 5878534 B has two organic fiber-reinforced layers helically wound around bead cores, the organic fiber cord of the organic fiber-reinforced layer on the inner layer side being wound with a gap at least partially in the circumferential direction. tires without overlap in the circumferential direction of the tire, and to cover at least part of the gap of the organic fiber-reinforced layer on the inner layer side, an organic fiber-reinforced layer is provided on the outer layer side, which prevents the strength of the carcass layer from being reduced.

In the pneumatic tire described in JP 4878179 B, the bead core includes a core body and a wrapping rubber layer, and a lower apex portion made of hard rubber has an L-shaped cross-section having a lower portion portion along the upper surface of the bead core at in the tire radial direction, and a rising portion portion rising from an inner end of the lower portion portion in the tire axial direction and extending outward in the tire radial direction. The hardness of the rubber of the wrapping rubber layer and the hardness of the rubber of the lower apex portion are in the range of 82 to 87°, and thus the rolling resistance performance is improved while ensuring a high degree of wear resistance of the bead. Moreover, in the pneumatic radial tire described in JP 4996112 B, three bead cover strips formed by a rubber coating of a plain weave fabric made of organic fiber are wound around the outer annular surfaces of the bead cores in an overlapping manner, and the overlap portion of the three bead cover strips is on one specific surface of the bead core, which prevents the bead core from losing its shape during mold vulcanization.

Technical problem

In recent years, to improve transportation efficiency, there has been a need to increase the size of vehicles used in mines, and the pneumatic tires mounted on such vehicles must also be extra-large pneumatic tires that can withstand increased load capacity and have an even larger load capacity. In an extra-large pneumatic tire, the bead core is substantially polygonal in shape in the meridional cross-section of the tire. To avoid stress concentration on the carcass near the corner of the bead core, some extra-large pneumatic tires include a nylon cover layer wrapped around the bead cores. However, when using only a nylon cover layer, the distance between the corner of the bead core and the frame is insufficient. Thus, when a large tensile force is applied to the frame, the area near the corner of the bead core and the frame rub against each other when receiving this large force, and as a result, the bead core can come out of the nylon cover layer. In this case, the bead core angle and the frame rub against each other and for this reason the frame cord may break. Thus, in a conventional pneumatic tire, there is scope for improvement in terms of wear resistance of the bead portion.

The present invention has been developed in view of the above description, and the object of the present invention is to provide a pneumatic tire that can provide improved wear resistance to a bead portion.

Solution

To solve the above problem and achieve the above object, the pneumatic tire according to the present invention may include a pair of bead portions, bead cores, a carcass, an organic fiber-reinforced inner layer, and a rubber reinforcing layer. A pair of bead portions may be located on either side of the equatorial plane of the tire in the lateral direction of the tire. Bead cores may be located in bead sections. The bead cores may be formed by winding bead wires into a ring and have a shape in the meridional cross section of the tire formed in a polygonal cross section. The frame may extend between bead portions on either side in the lateral direction of the tire. The frame may extend through the inner side of the bead core in the tire radial direction from the inner side of the bead core in the tire transverse direction and be folded back toward the outer side in the tire transverse direction in the bead portion. The carcass may be formed by covering the carcass cord with cover rubber. The inner organic fiber reinforced layer may be wound around the bead core and formed by covering the organic fiber cord with a cover rubber. The rubber reinforcing layer may be disposed between the inner organic fiber-reinforced layer and the carcass so as to cover at least the apex on the innermost side of the bead core in the lateral direction of the tire. The shortest distance between the bead wire and the carcass cord may be 3 mm or more.

Further, in the pneumatic tire, the rubber reinforcing layer is preferably arranged to extend through the inner side of the bead core in the tire radial direction from the inner side of the bead core in the tire lateral direction to the outer side of the bead core in the tire lateral direction. Between the rubber reinforcing layer and the carcass there is preferably a rubber adhesive layer extending through the inner side of the bead core in the tire radial direction from the inner side of the bead core in the tire lateral direction to the outer side of the bead core in the tire lateral direction. The rubber adhesive layer preferably has a rubber hardness equal to or higher than the rubber hardness of the carcass cover rubber. The rubber reinforcing layer preferably has a rubber hardness higher than the rubber hardness of the rubber adhesive layer and the rubber hardness of the covering rubber of the inner organic fiber reinforced layer. The rubber adhesive layer preferably has a sulfur content equal to or greater than the sulfur content of the carcass cover rubber.

Moreover, in the pneumatic tire, the rubber adhesive layer preferably has a rubber hardness in the range of 72 or more and 78 or less.

Moreover, in the pneumatic tire, in portions located on the inner side of the bead core in the tire lateral direction of the rubber adhesive layer and the rubber reinforcing layer, an end portion on the outer side of the rubber adhesive layer in the tire radial direction is preferably located further on the outer side in the tire radial direction, than the end portion on the outer side of the rubber reinforcing layer in the radial direction of the tire.

Moreover, in the pneumatic tire, the rubber reinforcing layer preferably has an end portion on the outer side in the tire radial direction located further on the outer side in the tire radial direction than the outer circumferential surface of the bead core.

Moreover, in the pneumatic tire, the rubber adhesive layer preferably contains a cobalt compound.

Moreover, the pneumatic tire preferably includes an outer organic fiber reinforced layer formed by covering the organic fiber cord with a cover rubber. The outer organic fiber reinforced layer is preferably located at least between the rubber reinforcing layer and the frame. The outer organic fiber reinforced layer is preferably arranged extending through the inner side of the bead core in the tire radial direction from the inner side of the bead core in the tire lateral direction to the outer side of the bead core in the tire lateral direction.

Moreover, in the pneumatic tire, the rubber reinforcing layer preferably has a rubber hardness equal to or higher than the hardness of the rubber of the inner organic fiber-reinforced layer cover rubber and the outer organic fiber-reinforced layer cover rubber.

Further, in a pneumatic tire, the organic fiber cord of the outer organic fiber-reinforced layer preferably has a thickness equal to or greater than the thickness of the organic fiber cord of the inner organic fiber-reinforced layer.

Moreover, in a pneumatic tire, the cover rubber of the outer organic fiber-reinforced layer preferably has a rubber hardness equal to or higher than the rubber hardness of the cover rubber of the inner organic fiber-reinforced layer.

Further, in a pneumatic tire, the outer organic fiber-reinforced layer is preferably formed by spirally winding a tape-like member around a bead core extending in a circumferential direction of the tire. The tape-like element is preferably wound helically, with adjacent annular portions in contact with each other.

Moreover, in a pneumatic tire, the inner organic fiber reinforced layer is preferably formed by spirally winding a tape-like member around a bead core extending in a circumferential direction of the tire. In the inner organic fiber-reinforced layer and the outer organic fiber-reinforced layer, the direction in which the tape-like element forming the inner fiber-reinforced layer is helically wound is the same as the direction in which the tape-like element forming the outer organic fiber-reinforced layer is helically wound.

Moreover, in a pneumatic tire, the shortest distance between the bead wire and the carcass cord is preferably in the range of 4 mm or more and 8 mm or less.

Moreover, in the pneumatic tire, the rubber reinforcing layer preferably has a rubber hardness in the range of 80 or more and 85 or less.

Moreover, in the pneumatic tire, the bead filler is preferably located on the inner side of the folded portion in the tire lateral direction and the outer side of the bead core in the tire radial direction. The folded portion is preferably a portion that is folded back toward the outer side of the bead core in the transverse direction of the tire in the casing. The rubber reinforcing layer preferably has a rubber hardness equal to or higher than the rubber hardness of the bead filler.

Advantages of the invention

The pneumatic tire according to an embodiment of the present invention has the advantageous effect of providing a bead portion with improved wear resistance.

Brief description of drawings

Fig. 1 is a meridional cross-sectional view illustrating a main portion of a pneumatic tire according to the first embodiment;

Fig. 2 is a detailed view of area A shown in FIG. 1;

Fig. 3 is an explanatory diagram illustrating a state in which the inner organic fiber-reinforced layer shown in FIG. 2, wound around the bead core;

Fig. 4 is a detail view of area B shown in FIG. 2;

Fig. 5 is a tire meridional cross-sectional view showing a main part of a pneumatic tire according to the second embodiment;

Fig. 6 is a detail view of portion C shown in FIG. 5;

Fig. 7 is an explanatory diagram illustrating a state in which the inner organic fiber-reinforced layer, the rubber reinforcement layer and the outer organic fiber-reinforced layer shown in FIG. 6, wound around the bead core;

Fig. 8 is a detailed view of portion D shown in FIG. 6;

Fig. 9 is a modified example of a pneumatic tire according to the first embodiment, showing an explanatory diagram of a state in which the outer end portion of the rubber reinforcing layer on the outer side in the lateral direction of the tire is located further on the inner side in the radial direction of the tire than the outer circumferential surface of the bead core ;

Fig. 10 is a modified example of a pneumatic tire according to the first embodiment, showing an explanatory diagram of a state in which the outer end portion of the rubber reinforcing layer on the inner side in the lateral direction of the tire is located further on the inner side in the radial direction of the tire than the outer circumferential surface of the bead core ;

Fig. 11 is a modified example of a pneumatic tire according to the first embodiment, showing an explanatory diagram of a state in which the outer end portions of the rubber reinforcing layer on both sides in the tire lateral direction are located further on the inner side in the tire radial direction than the outer circumferential surface of the bead core ;

Fig. 12 is a modified example of a pneumatic tire according to the first embodiment, showing an explanatory diagram for the case where the cross-sectional shape of the bead core is octagonal;

Fig. 13 is a modified example of a pneumatic tire according to the second embodiment, showing an explanatory diagram of a state in which the rubber reinforcing layer is located from the inner side of the bead core in the tire lateral direction to the outer side in the tire lateral direction;

Fig. 14 is a modified example of a pneumatic tire according to the second embodiment, showing an explanatory diagram for the case where the rubber reinforcing layer is disposed on the inner side of the bead core in the lateral direction of the tire;

Fig. 15 is a modified example of a pneumatic tire according to the second embodiment, showing an explanatory diagram of a state in which the outer organic fiber-reinforced layer is located from the inner side of the bead core in the tire lateral direction to the outer side in the tire lateral direction;

Fig. 16 is a modified example of a pneumatic tire according to the second embodiment, showing an explanatory diagram for the case where the cross-sectional shape of the bead core is octagonal;

Fig. 17 is a modified example of a pneumatic tire according to the first embodiment, showing an explanatory diagram for a case where a plurality of bead cores are arranged in a bead portion;

Fig. 18 is a modified example of a pneumatic tire according to the second embodiment, showing an explanatory diagram for a case where a plurality of bead cores are arranged in a bead portion;

Fig. 19A is a table showing the results of the first test to evaluate the performance of pneumatic tires;

Fig. 19B is a table showing the results of the first test to evaluate the performance of pneumatic tires;

Fig. 20A is a table showing the results of a second test to evaluate the performance of pneumatic tires; And

Fig. 20B is a table showing the results of a second test to evaluate the performance of pneumatic tires.

Description of Embodiments of the Invention

Below, pneumatic tires in accordance with embodiments of the present invention are described in detail with reference to the drawings. However, the present invention is not limited to this embodiment. The components of the following embodiments include elements that can be substituted and are fully understandable to one skilled in the art or that are substantially identical.

First embodiment

In the following description, the term "tire radial direction" means the direction perpendicular to the rotation axis (not shown) of the tire, which is the rotation axis of the pneumatic tire 1, the term "inner side in the tire radial direction" means the side facing the tire rotation axis in the tire radial direction , and the term “outer side in the tire radial direction” means the side distant from the rotation axis of the tire in the tire radial direction. The term “tire circumferential direction” means a direction along a circle with the tire rotation axis as the centerline. In addition, the term "tire lateral direction" means a direction parallel to the rotation axis of the tire, the term "inner side in the tire lateral direction" means the side facing the tire equatorial plane CL (tire equatorial line) in the tire lateral direction, and the term "outer side in the tire lateral direction" means the side distant from the equatorial plane CL of the tire in the tire lateral direction. The term "tire equatorial plane CL" means a plane perpendicular to the rotation axis of the tire and passing through the center of the tire width in the pneumatic tire 1. The tire equatorial plane CL in the tire lateral direction is aligned with the center line of the tire lateral direction, which corresponds to the center position of the pneumatic tire 1 in the lateral direction direction of the bus. The width of the tire is the width in the lateral direction of the tire between the portions located on the outermost sides in the lateral direction of the tire, or, in other words, the distance between the portions furthest from the equatorial plane CL of the tire in the lateral direction of the tire. The term “tire equatorial line” refers to a line extending in the circumferential direction of the pneumatic tire 1 and located in the equatorial plane CL of the tire. In the following description, the term “tire meridional cross-section” means a cross-section of the tire along a plane that includes the axis of rotation of the tire.

In FIG. 1 is a meridional cross-sectional view illustrating a main portion of the pneumatic tire 1 according to the first embodiment. The pneumatic tire 1 according to the first embodiment is a radial tire for a construction vehicle, which is called an off-road tire (OR tire). The pneumatic tire 1 shown in FIG. 1 as a first embodiment is provided with a tread portion 2 in an outermost profile portion in the radial direction of the tire as viewed from a meridional cross-section of the tire, the tread portion 2 being formed from a tread rubber 2a which is a rubber composition. The surface of the tread portion 2, in other words, the portion that comes into contact with the road surface when the vehicle (not shown) with the pneumatic tire 1 mounted thereon is driven, is formed as a tread contact surface 3.

A plurality of grooves, such as longitudinal grooves 15 extending in the tire circumferential direction and lug grooves extending in the tire transverse direction (not shown), are formed on the tread contact surface 3 of the tread portion 2, and a plurality of tread portions 10 are defined and formed by the grooves in section 2 treads.

Both ends of the tread portion 2 in the tire transverse direction are configured as shoulder portions 4. The sidewall portions 5 are located from the shoulder portions 4 to predetermined inner side locations in the tire radial direction. In other words, the sidewall portions 5 are located at two locations on both sides of the pneumatic tire 1 in the tire lateral direction. The sidewall portion 5 includes a sidewall rubber 5a, which is a rubber composition. Moreover, at a position on the innermost side in the radial direction of the tire, a rim reference line 9 is formed on each of the sidewall portions 5 on both sides in the lateral direction of the tire. The rim reference line 9 projects from the surface of the sidewall portion 5 and is formed along the entire circumference in the circumferential direction of the tire.

In addition, the bead portion 20 is located on the inner side of each sidewall portion 5 in the tire radial direction, and similar to the sidewall portions 5, the bead portions 20 are located at two locations on both sides of the equatorial plane CL of the tire. In other words, a pair of bead portions 20 are located on both sides of the tire equatorial plane CL in the tire lateral direction. The bead cores 21 are located in a pair of corresponding bead portions 20, and the bead filler 40 is located on the outer side of each bead core 21 in the tire radial direction. The bead core 21 is formed by winding bead wires 28 (see FIG. 4), which are steel wires, into a ring. The bead filler 40 is a rubber material located in the space formed by reversing the end portion of the carcass 6 described below in the tire lateral direction to the outer side in the tire lateral direction at the location of the bead core 21. In addition, the bead filler 40 includes a lower filler 41 positioned to abut the outer annular surface of the bead core 21, and an upper filler 42 located at a location even closer to the outer side in the tire radial direction than the lower filler 41. .

The bead section 20 is configured to be mounted on a disc rim, including a specified rim R with a 5° taper. In other words, the pneumatic tire 1 according to the first embodiment can be mounted on a specified rim R, including a portion corresponding to a bead portion 20 that is inclined toward the outer side in the radial direction of the tire as this portion extends from the inner side to the outer side in the transverse direction of the tire at an inclination angle of 5°±1° relative to the axis of rotation of the rim. It should be noted that the term “specified rim” means “applicable rim” as defined by the Japan Automobile Tire Manufacturers Association (JATMA), “design rim” as defined by the Tire and Wheel Manufacturers Association (TRA) or “measurement rim” as defined by the European Technical Organization on tires and wheels (ETRTO).

On the inner side of the tread section 2 in the radial direction of the tire there is a belt layer 7. The belt layer 7 has a multi-layer structure in which three or more belt layers are stacked, and in a typical OR tire there are four to eight belt layers. In the first embodiment, the breaker layer 7 is formed by stacked six breaker layers 7a, 7b, 7c, 7d, 7e and 7f. The breaker layers 7a, 7b, 7c, 7d, 7e and 7f provided in the breaker layer 7 are formed by covering a plurality of breaker cords made of steel or organic fiber material with cover rubber and rolling the coated breaker cords. In addition, the belt cords of the belt layers 7a, 7b, 7c, 7d, 7e and 7f have mutually different inclination angles in the tire transverse direction relative to the tire circumferential direction, and the belt layers 7a, 7b, 7c, 7d, 7e and 7f are laminated in this manner that the directions of inclination of the breaker cords intersect with each other and are thus designed in the form of a so-called cross-breaker structure. Thus, the structural strength of the breaker layer 7 increases. The six breaker layers 7a, 7b, 7c, 7d, 7e and 7f include, for example, cross breakers 7a, 7b, 7c and 7d and security breaker layers 7e and 7f.

The carcass 6, which includes the radial ply cord, is provided to be formed continuously on the inner side of the belt ply 7 in the tire radial direction and on the tire equatorial plane CL side of the sidewall portion 5. The carcass 6 has a single-layer structure made of a single carcass ply or a multi-layer structure made of a plurality of layered carcass layers, and extends between the bead cores 21 on both sides in the torus-shaped tire transverse direction to form a tire core. In particular, the carcass 6 extends between a pair of bead portions 20 and is positioned to extend from one bead portion 20 of the pair of bead portions 20 to another bead portion 20 located on both sides in the lateral direction of the tire. In addition, the carcass 6 extends through the inner side of the bead core 21 in the tire radial direction from the inner side of the bead core 21 in the tire lateral direction and is folded back toward the outer side in the tire lateral direction in the bead portion 20 so as to wrap around the bead core 21 and filler 40 boards. In other words, the carcass 6 is reverse-wrapped around the bead core 21 from the inside of the bead core 21 in the tire lateral direction to the outside of the bead core 21 in the tire lateral direction in the bead portion 20.

That is, the carcass 6 includes a carcass body portion 6a located between a pair of bead portions 20 and a folded portion 6b formed continuously from the carcass body portion 6a and reversed from the inner side in the tire lateral direction to the outer side in the lateral tire direction. core 21 sides. The carcass body portion 6a referred to herein is a portion formed between the inner sides of a pair of bead cores 21 in the tire lateral direction in the carcass 6, and the folded portion 6b is a portion formed continuously from the carcass body portion 6a on the inner side of the core 21. a bead in the tire lateral direction extending through the inner side of the bead core 21 in the tire radial direction and folded back toward the outer side in the tire lateral direction. The bead filler 40 is located on the inner side of the folded portion 6b in the tire lateral direction, which is a portion folded in the opposite direction to the outer side of the bead core 21 in the tire lateral direction, and on the outer side of the bead core 21 in the tire radial direction.

The carcass carcass layer 6 arranged in this manner is formed by covering a plurality of carcass cords 6c (see FIG. 2) in the form of cord members made of steel or organic fiber material such as aramid, nylon, polyester or rayon with covering rubber. 6d (see Fig. 2), which is a rubber element, and rolling of the covered cords. In addition, the frame 6 has a frame inclination angle of 85° or more and 95° or less; wherein the carcass inclination angle is the inclination angle of the carcass cords 6c with respect to the circumferential direction of the tire.

Additionally, along the frame 6 on the inner side of the frame 6 or on the inner side of the frame 6 in the pneumatic tire 1, a pressurized layer 8 is formed.

In FIG. 2 is a detailed view of area A shown in FIG. 1. The bead core 21 is configured to have a polygonal cross-sectional shape when viewed from the meridional cross-section of the tire. In the first embodiment, the bead core 21 is designed to have a substantially hexagonal cross-sectional shape. Specifically, the bead core 21 is formed such that the lower portion 23 of the bead core corresponding to the inner annular surface of the bead core 21 and the outer annular surface 22 of the bead core in the overall view of the bead core 21 are substantially parallel to each other, and the bead core 21 is formed in locations on respective end sides in the tire lateral direction in a substantially hexagonal shape having corner portions projecting in the tire lateral direction, the lower bead core portion 23 being the inner annular surface of the bead cores 21 as viewed through the entire bead core 21, and has corner portions projecting in the tire lateral direction at locations on both sides in the tire lateral direction. In other words, the bead core 21 is formed between the outer annular surface 22 and the lower bead core portion 23 in the tire radial direction, having the innermost bead core point 26 as the innermost vertex in the tire lateral direction, and the outermost bead core point 27 as the outer apex in the transverse direction of the tire.

It should be noted that in this case, the lower portion 23 of the bead core of the bead core 21 relates to a surface in a meridional cross section indicated by an imaginary straight line contacting a portion of a plurality of bead wires 28 (see FIG. 4) arranged in a row at a location on the inner side of the bead core 21 in the tire radial direction to form a surface of the bead core 21, which portion is open to the surface of the bead core 21. Likewise, the outer annular surface 22 of the bead core 21 refers, when viewing the pneumatic tire 1 in the tire's meridional cross-section, to a surface designated by an imaginary straight line contacting a portion of a plurality of bead wires 28 arranged in a row at a location on the outer side of the core. 21 beads in the radial direction of the tire to form a surface of the bead core 21, which portion is open from the surface of the bead core 21.

The bead portion 20 includes a main bead portion 30 located on the inner annular surface of the bead portion 20. The main bead portion 30 of the tire is located on the inner side of the bead core 21 in the tire radial direction and is configured to be inclined relative to the rotation axis of the tire in a direction in which the main bead portion 30 of the tire expands toward the outer side in the radial direction of the tire as the main bead portion 30 expands toward the outer side in the tire radial direction. the tire portion 30 extends from an inner side in the tire lateral direction to an outer side in the lateral tire direction.

The bead tape, as a reinforcing layer that strengthens the frame 6, is located in a section of the frame 6, which is wrapped in the opposite direction around the bead core 21. Examples of the applicable bead tape include a steel bead formed using steel cords as cord members, or a nylon bead formed using cord members made of an organic fiber-based material. The nylon bead tape includes, for example, a sheet member formed by laying and rolling a plurality of organic fiber cords, a fabric formed by weaving a plurality of organic fiber cords, or a composite material formed by rubberizing a sheet member or fabric. In the first embodiment, a steel bead strip 45 is provided as the bead strip using steel cord.

The steel bead tape 45 is located on the outer side of the frame 6 on a section of the frame 6 wrapped in the opposite direction with the possibility of being applied to the frame 6 similarly to the frame 6, wrapped in the opposite direction around the bead core 21 from the inside to the outside in the transverse direction of the tire, and is located continuously in the direction along the circumference of the tire. In other words, in a portion where the carcass 6 is located further on the inner side in the tire lateral direction than the bead core 21, the steel bead strip 45 is located on the inner side of the carcass 6 in the tire lateral direction, in a portion where the carcass 6 is located further on the inner side. in the tire radial direction than the bead core 21, the steel bead strip 45 is located on the inner side of the carcass 6 in the tire radial direction, and in the portion where the carcass 6 is located further on the outer side in the tire lateral direction than the bead core 21, the steel bead strip 45 is located on the outer side of the frame 6 in the transverse direction of the tire.

The breaker rubber element 35 is located on the outer side of the steel side strip 45 in the side section 20. Similar to the steel bead strip 45, the belt rubber element 35 is located from the inner side of the bead core 21 in the tire transverse direction to the inner side of the bead core 21 in the tire radial direction and the outer side of the bead core 21 in the tire transverse direction and extends continuously in the circumferential direction of the tire. The breaker rubber element 35, arranged in this manner, forms the contact surface of the bead portion 20 for the flange of the specified rim R.

The bead portion 20 further includes an inner organic fiber-reinforced layer 50, a rubber reinforcing layer 60, and a rubber adhesive layer 70. Among them, the inner organic fiber-reinforced layer 50 is wound around the entire circumference of the bead core 21 relative to the bead core 21 in the meridional cross section of the tire.

The rubber reinforcing layer 60 is disposed between the inner organic fiber-reinforced layer 50 and the frame 6 to cover from the outer side of the inner organic fiber-reinforced layer 50 to at least the innermost point 26 of the bead core, which is the apex on the innermost side of the bead core 21 in cross-section. direction of the bus. In the present embodiment, the rubber reinforcing layer 60 between the inner organic fiber reinforced layer 50 and the carcass 6 extends through the inner side of the bead core 21 in the tire radial direction and is located from the inner side of the bead core 21 in the tire lateral direction to the outer side of the bead core 21 in the lateral direction. tires. In other words, in the meridional cross section of the tire, when the direction approaching the center of gravity of the bead core 21 is defined as the inner side direction when starting from the bead core 21, and the direction away from the center of gravity of the bead core 21 is defined as the outer side direction when starting from bead core 21, the rubber reinforcing layer 60 is located on the outer side of the inner organic fiber-reinforced layer 50 from the bead core 21.

The rubber adhesive layer 70 between the rubber reinforcing layer 60 and the carcass 6 extends through the inner side of the bead core 21 in the tire radial direction and is located from the inner side of the bead core 21 in the tire lateral direction to the outer side of the bead core 21 in the tire lateral direction. In other words, the rubber adhesive layer 70 is located on the outer side of the rubber reinforcing layer 60, as viewed from the bead core 21, in the meridional cross section of the tire.

In FIG. 3 is an explanatory diagram illustrating a state in which the inner organic fiber-reinforced layer 50 shown in FIG. 2, wound around core 21 beads. The inner organic fiber-reinforced layer 50 wound around the bead core 21 is formed by helically winding the inner organic fiber-reinforced material 55, which is a ribbon-like member, around the bead core 21 extending in the circumferential direction of the tire. In other words, the bead core 21 is formed by winding one or a plurality of bead wires 28 made of steel into a ring in a plurality of layers, and the inner organic fiber-reinforced layer 50 is formed by spirally winding the inner organic fiber-reinforced material 55 on the outer side of the bead wires 28. wound in many layers.

In other words, in the inner organic fiber-reinforced layer 50, the inner organic fiber-reinforced material 55 is helically wound around the surface of the bead core 21 along the longitudinal direction of the bead core 21, with the bead core 21 extending in the circumferential direction of the tire as the center of the helix. Here, the inner organic fiber reinforced material 55 is helically wound, and adjacent annular portions are in contact with each other. In other words, the inner organic fiber reinforced material 55 is helically wound, with adjacent annular portions adjacent or overlapping. In the first embodiment, the inner organic fiber-reinforced material 55 is wound, and a portion of the adjacent annular portions in the transverse direction of the inner organic fiber-reinforced material 55 formed in a tape-like shape is overlapped. Thus, the inner organic fiber reinforced layer 50 is wound without play over the entire surface of the bead core 21. The bead wires 28, wound in multiple layers, are bonded by an inner organic fiber reinforced layer 50 wound around the bead core 21 to prevent them from coming apart.

The rubber reinforcing layer 60 is located on the outer side of the inner organic fiber-reinforced layer 50, as viewed from the bead core 21, relative to the inner organic fiber-reinforced layer 50 thus formed, and is located along the carcass 6 so that the shape in the meridional cross-section of the tire is A U-shape in which the outer side in the radial direction of the tire is the open side. In other words, the rubber reinforcing layer 60 is located along the frame body portion 6a and the folded portion 6b of the frame 6, and the bead core 21, around which the inner organic fiber reinforced layer 50 is wound, is located on the inner side of the U-shaped rubber reinforcing layer 60, which is located in U-shaped along the frame 6.

Specifically, in the rubber reinforcing layer 60, the outer end portion 61, which is an end portion on the outer side in the tire radial direction, is located further on the outer side in the radial direction of the tire than the outer circumferential surface 22 of the bead core 21. Specifically, in the rubber reinforcing layer 60 formed in a U-shape in the meridional cross section of the tire, both of the outer end portion 61 of the portion located further on the inner side in the tire lateral direction than the bead core 21 and the outer end portion 61 of the portion located further on the outer side in the tire lateral direction than the bead core 21 are located further on the outer side in the tire radial direction than the outer annular surface 22 of the bead core 21. Thus, the rubber reinforcing layer 60 is arranged to cover the innermost point 26 of the bead core of the bead core 21 on the inner side of the bead core 21 in the tire lateral direction and covers the outermost point 27 of the bead core of the bead core 21 on the outer side of the bead core 21 in the lateral direction. direction of the tire.

In addition, the rubber adhesive layer 70 located between the rubber reinforcing layer 60 and the frame 6 is located on the outer side of the rubber reinforcing layer 60 from the bead core 21 relative to the rubber reinforcing layer 60, and is located along the frame 6 so that the shape in the meridional cross section of the tire is U-shaped, in which the outer side in the radial direction of the tire is an open side similar to the rubber reinforcing layer 60. In other words, the rubber adhesive layer 70 is located along the carcass body portion 6a and the folded portion 6b of the carcass 6 on the outer side of the rubber reinforcing layer 60, and the rubber reinforcing layer 60 is located on the inner side of the U-shaped rubber adhesive layer 70, which is arranged in a U-shape along the frame 6.

Specifically, in the rubber adhesive layer 70 formed in a U-shape in the meridional cross section of the tire, the outer end portions 71, which are end portions on the outer side in the radial direction of the tire at both the inner-side location and the on the outer side of the core 21, the beads in the tire lateral direction are located further on the outer side in the tire radial direction than the outer end portions 61 of the rubber reinforcing layer 60. In other words, in the portions located on the inner side in the tire lateral direction of the bead core 21, the rubber adhesive layer 70 and the rubber reinforcing layer 60, the outer end portions 71 of the rubber adhesive layer 70 are located further on the outer side in the radial direction of the tire than the outer end portions 61 of the rubber reinforcing layer 60. Likewise, in the portions located on the outer side of the bead core 21 in the transverse direction tires of the rubber adhesive layer 70 and the rubber reinforcing layer 60, the outer end portions 71 of the rubber adhesive layer 70 are located further on the outer side in the radial direction of the tire than the outer end portions 61 of the rubber reinforcing layer 60.

In portions of the rubber adhesive layer 70 and the rubber reinforcing layer 60 located on the same side relative to the bead core 21 in the tire lateral direction, the outer end portion 71 of the rubber adhesive layer 70 is preferably located on the outer side in the tire radial direction relative to the outer end portion 61 rubber reinforcing layer 60 ranging from 5 mm or more to 15 mm or less.

The outer surface of the rubber adhesive layer 70, as viewed from the bead core 21, that is, the surface on the side facing the frame 6, is in close contact with the frame 6. The outer surface of the rubber reinforcing layer 60, as viewed from the bead core 21, is That is, the surface on the side facing the rubber adhesive layer 70 is in close contact with the rubber adhesive layer 70. In addition, the surface of the rubber reinforcing layer 60 on the side facing the inner organic fiber reinforced layer 50 is in close contact with the inner. organic fiber reinforced layer 50 at least in the range from the innermost point 26 of the bead core to the outermost point 27 of the bead core 21, passing through the side of the lower part of the bead core 23 in the meridional cross section of the tire.

Among the inner organic fiber reinforced layer 50, the rubber reinforcing layer 60 and the rubber adhesive layer 70 arranged as described above, the inner organic fiber reinforced layer 50 wound around the bead core 21 is formed by covering the cover rubber 52 with an organic fiber cord 51 that represents is a cord element made from an organic fiber-based material such as aramid, nylon, polyester or rayon.

Specifically, in the inner organic fiber-reinforced layer 50, in the state of the inner organic fiber-reinforced material 55, which is a tape-shaped member forming the inner organic fiber-reinforced layer 50, a plurality of organic fiber cords 51 are arranged in parallel order in the transverse direction of the belt, and each The organic fiber cords 51 are arranged to extend in a length direction of the inner organic fiber reinforced material 55. The cover rubber 52 completely covers a plurality of organic fiber cords 51 arranged in a lateral direction in the belt direction of the inner organic fiber reinforced material 55 as described above, thereby holding together a plurality of organic fiber cords 51 as a unit. In addition, since the organic fiber cord 51 is arranged to extend in the length direction of the inner organic fiber-reinforced material 55, due to the inner organic fiber-reinforced material 55 helically wound around the bead core 21, the organic fiber cord 51 is also helically wound around the core. 21 sides.

The rubber reinforcing layer 60 located on the outer side of the inner organic fiber reinforced layer 50 is formed from a sheet rubber member and has a rubber hardness higher than the rubber hardness of the surrounding rubber member. The hardness of the rubber of the rubber reinforcing layer 60 is, for example, higher than the hardness of the rubber of the cover rubber 52 of the inner organic fiber reinforced layer 50, and higher than the hardness of the rubber of the cover rubber 6d of the frame 6. The hardness of the rubber of the rubber reinforcing layer 60 is equal to or higher than the hardness of the filler rubber 40 boards. In particular, the hardness of the rubber of the rubber reinforcing layer 60 is equal to or higher than the hardness of the rubber of the lower filler 41 of the bead filler 40 located adjacent to the outer annular surface of the bead core 21.

Specifically, the rubber reinforcing layer 60 has a rubber hardness in the range of 80 or more and 85 or less. In the first embodiment, the hardness of the rubber is the JIS-A hardness of rubber in accordance with JIS K6253, expressed in rubber hardness units.

The rubber adhesive layer 70 located between the rubber reinforcement layer 60 and the frame 6 on the outer side of the rubber reinforcement layer 60 is formed from a rubber sheet member and has a rubber hardness equal to or higher than the rubber hardness of the cover rubber 6d of the frame 6. The rubber hardness of the rubber adhesive layer is 70 more. lower than the hardness of the rubber of the rubber reinforcing layer 60, that is, the hardness of the rubber of the rubber reinforcing layer 60 is higher than the hardness of the rubber of the rubber adhesive layer 70. The rubber adhesive layer 70 formed in this manner has a rubber hardness in the range of 72 or more and to 78 or less.

Since the hardness of the rubber of each rubber element has such a relationship, when this relationship is expressed using the inequality sign, the hardness of the rubber has the following relationship: cover rubber 6d frame 6 < rubber adhesive layer 70 < rubber reinforcing layer 60, and also has the following relationship: cover rubber 52 inner organic fiber reinforced layer 50 < rubber reinforcing layer 60. The relationship for the rubber hardness value expressed in JIS-A hardness units in this case differs by 1 or more.

The sulfur content of the rubber adhesive layer 70 is equal to or greater than the sulfur content of the lining rubber 6d of the frame 6, that is, the sulfur content of the rubber adhesive layer 70 in parts by weight is equal to or greater than the sulfur content of the lining rubber 6d of the frame 6. Specifically, the sulfur content of the rubber adhesive layer 70 is preferably in the range of 2 parts by mass or more and 10 parts by mass or less. In addition, the rubber adhesive layer 70 is formed from a rubber element containing a cobalt compound.

In FIG. 4 is a detailed view of area B shown in FIG. 2. The inner organic fiber reinforced layer 50, the rubber reinforcing layer 60 and the rubber adhesive layer 70 are arranged between the bead core 21 and the frame 6. Among them, the inner organic fiber reinforced layer 50 has a thickness Wf ranging from 1 mm or more to 3 mm or more. less. The rubber reinforcing layer 60 has a thickness Wr ranging from 1 mm or more to 7 mm or less, and the rubber adhesive layer 70 has a thickness Wa ranging from 1 mm or more to 3 mm or less.

Since the corresponding members between the bead core 21 and the frame 6 are formed to have the specified thickness values, the shortest distance between the bead wire 28 provided by the bead core 21 and the carcass cord 6c provided by the frame 6 is in the range of 3 mm or more to 10 mm or less. The bead core 21 is configured to have a substantially hexagonal cross-sectional shape as a shape in the meridional cross-section of the tire. Thus, the shortest distance between the bead wire 28 provided by the bead core 21 and the carcass cord 6c provided by the carcass 6 is the distance between the bead wire 28 located on any of the corner portions of the bead core 21 formed in a substantially hexagonal cross-sectional shape. , and a carcass cord 6c provided by the carcass 6.

Thus, the distance between the bead wire 28 located on the corner portion of the bead core 21, which projects outwardly when viewed from the center side in the cross-sectional shape of the bead core 21, and the carcass cord 6c of the carcass 6 is 3 mm or more at any corner plot. Accordingly, for example, the distance between the innermost point 26 of the bead core and the carcass cord 6c provided by the carcass 6 is also 3 mm or more. It should be noted that the shortest distance between the bead wire 28 and the carcass cord 6c is preferably in the range of 4 mm or more and 8 mm or less.

In the case where the pneumatic tire 1 configured as described above is mounted on a vehicle, the tire main bead portion 30 is first mounted on a specified rim R provided by the wheel rim for mounting the pneumatic tire 1 on the specified rim R, and the pneumatic tire 1 is mounted on the wheel rim . After mounting on the rim, the pneumatic tire 1 is inflated, and the inflated pneumatic tire 1 is installed on the vehicle. The pneumatic tire 1 according to the first embodiment is mounted on a large vehicle such as a vehicle used, for example, in a mine and used under heavy load conditions.

When the vehicle on which the pneumatic tires 1 are mounted moves, the pneumatic tire 1 rotates while the tread contact surface 3 located on the lower side in the tread contact surface 3 comes into contact with the road surface. The vehicle moves by transmitting a traction force or a braking force to the road surface, using a frictional force between the tread contact surface 3 and the road surface, or by generating a rotational force.

When a vehicle with pneumatic tires 1 mounted on it moves, although the vehicle can be moved by the frictional force generated between the contact surface 3 of the tread of the pneumatic tire 1 and the road surface in the specified manner, each part of the pneumatic tire 1 while the vehicle is moving the product experiences loads acting in different directions. The load acting on the pneumatic tire 1 is carried by the air under pressure inside the pneumatic tire 1, the frame 6 provided as the frame of the pneumatic tire 1, etc.

For example, due to the weight of the vehicle, as well as the presence of depressions and protrusions on the road surface, the load acting in the radial direction of the tire between the tread portion 2 and the bead portion 20 is mainly borne by the air pumped under pressure inside the pneumatic tire 1, or deflection of sidewall section 5 or the like. In particular, since the pneumatic tire 1 according to the first embodiment is mounted on a large vehicle and is used under heavy load conditions, the sidewall portions 5 and the carcass 6 bear a very large load. Accordingly, the frame 6 is subjected to a large tensile force.

The frame 6 is folded back around the bead core 21 in the bead portion 20 so that it is held by the bead portion 20. Thus, when a large tensile force is applied to the frame 6, the tensile force of the frame 6 is transferred to the bead core 21, and a large force is exerted between the frame 6 and the bead core 21. In other words, since the carcass 6, being reversed around the bead core 21, is held by the bead portion 20, when a tensile force is applied to the carcass 6, a tensile force in the direction from the side of the bead portion 20 to the outer side in the tire radial direction is exerted on section 6a of the frame body. As a result, a large force also acts between the bead core 21 and the frame 6.

Here, the sidewall portion 5 is inclined with respect to the tire radial direction in the direction from the position of the bead portion 20 toward the outer side in the tire lateral direction as the direction toward the outer side in the tire radial direction. Thus, when a large tensile force is applied to the carcass body portion 6a while the carcass body portion 6a is pulled in the tire radial direction, the carcass body portion 6a generates a force toward the outer side in the tire lateral direction near the bead portion 20.

On the other hand, the bead core 21 is formed to have a substantially hexagonal cross-sectional shape in the tire meridional cross-section and has a plurality of corner portions in the tire meridional cross-section, and the innermost point of the bead core 26 is a corner portion projecting toward the inner side. in the transverse direction of the tire. Thus, when a large tensile force is applied to the carcass 6 and the carcass body portion 6a tries to move in the radial direction of the tire due to the tensile force while generating a force in the outer side in the lateral direction of the tire near the bead portion 20, the carcass body portion 6a rubs against the most the inner point 26 of the bead core, while applying a large load to it. As a result, in the carcass body portion 6a, the cover rubber 6d is worn and the carcass cord 6c is directly abraded, and there is a possibility of damage such as rupture of the carcass cord 6c occurring.

In addition, since the frame 6 is reversed around the bead core 21, when a large tensile force is applied to the frame 6, the frame 6 and the bead core 21 rub against each other also at a location other than the innermost point 26 of the bead core, and the carcass 6 possibly causes damage such as rupture of the carcass cord 6c due to abrasion.

On the other hand, in the pneumatic tire 1 according to the first embodiment, the inner organic fiber reinforced layer 50 is wound around the bead core 21, and the rubber reinforcing layer 60 covering at least the innermost point 26 of the bead core is disposed between the inner organic fiber reinforced layer. 50 and the frame 6. Thus, even when there is a large force between the frame 6 and the bead core 21 due to the large tensile force acting on the frame 6, this force acting between the frame 6 and the bead core 21 can be dispersed by the rubber reinforcing layer 60, possessing elasticity and high hardness of rubber. In this way, wear of the cover rubber 6d due to the force acting between the carcass 6 and the bead core 21 can be prevented, and damage such as breaking of the carcass cord 6c can be prevented.

In addition, since the shortest distance between the bead wire 28 of the bead core 21 and the carcass cord 6c of the carcass 6 is 3 mm or more, even when a large force is applied between the carcass 6 and the bead core 21, the force is easily dispersed by a rubber member or the like. between bead wires 28 and carcass cord 6c. As a result, the stress concentration when a large force acts between the frame 6 and the bead core 21 can be weakened, and, for example, the stress concentration between the corner portion of the bead core 21 formed with a substantially hexagonal cross-sectional shape and the frame 6 can be weakened. In this way, damage such as breaking of the carcass cord 6c can be more effectively prevented. As a result, the wear resistance of the bead portion 20 can be improved.

In addition, since the rubber adhesive layer 70 having a rubber hardness equal to or higher than the rubber hardness of the cover rubber 6d of the frame 6 is located between the rubber reinforcing layer 60 and the frame 6, even when a large force is applied between the frame 6 and the bead core 21, the force can be further dispersed by the rubber adhesive layer 70. In addition, the hardness of the rubber of the rubber reinforcing layer 60 is higher than that of the rubber of the rubber adhesive layer 70 and the hardness of the rubber of the covering rubber 52 of the inner organic fiber reinforced layer 50. Thus, damage to the frame 6 caused by force acting between the frame 6 and the bead core 21 can be more effectively prevented by the rubber reinforcing layer 60 and the rubber adhesive layer 70.

In addition, since the sulfur content of the rubber adhesive layer 70 is equal to or higher than the sulfur content of the carcass cover rubber 6d 6, the sulfur component of the carcass cover rubber 6d 6 can be prevented from flowing into the rubber adhesive layer 70, and delamination between the cover rubber 6d and the carcass cord can be prevented. 6c of the carcass 6. In other words, since the sulfur component of the cover rubber 6d also serves as an adhesive component in the cover rubber 6d, when the sulfur component of the cover rubber 6d flows out, the adhesive component is reduced, and thus between the cover rubber 6d and the carcass cord 6c delamination may occur. Here, when the rubber members are in contact with each other, the sulfur component contained in the rubber member substantially flows out from the rubber member having a relatively large sulfur content into the rubber member having a small sulfur content. Thus, when the sulfur content in the rubber adhesive layer 70 in contact with the frame 6 is less than the sulfur content in the cover rubber 6d of the frame 6, the sulfur component in the cover rubber 6d is likely to flow into the rubber adhesive layer 70.

On the other hand, in the first embodiment, since the sulfur content of the rubber adhesive layer 70 in contact with the frame 6 is equal to or greater than the sulfur content of the cover rubber 6d of the frame 6, it is possible to prevent the sulfur component from leaking out of the cover rubber 6d of the frame 6 into rubber adhesive layer 70. As a result, the adhesive component in the carcass cover rubber 6d 6 can be prevented from being reduced, and delamination between the cover rubber 6d and the carcass cord 6c can be prevented. Thus, not only is the carcass cord 6c ruptured, but also delamination between the carcass cord 6c and the cover rubber 6d is prevented, and damage to the bead portion 20 can be more effectively prevented. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

In addition, since the rubber hardness of the rubber adhesive layer 70 ranges from 72 or more to 78 or less, rupture of the carcass cord 6c can be more effectively prevented while preventing delamination between the rubber adhesive layer 70 and surrounding members. In other words, in the case where the hardness of the rubber of the rubber adhesive layer 70 is less than 72, the hardness of the rubber of the rubber adhesive layer 70 is excessively small, and thus it may be difficult to relieve the stress concentration between the frame 6 and the bead core 21. In this case, it may be difficult to effectively prevent the carcass cord 6c from breaking due to the force acting between the carcass 6 and the bead core 21. In addition, when the hardness of the rubber of the rubber adhesive layer 70 is more than 78, the hardness of the rubber of the rubber adhesive layer 70 is excessively large, and thus the difference in rubber hardness between the rubber adhesive layer 70 and the cover rubber 6d of the frame 6 may be excessively large. In this case, there is a possibility that delamination is likely to occur due to an excessively large difference in rubber hardness between the rubber adhesive layer 70 and the cover rubber 6d of the frame 6.

On the other hand, when the rubber hardness of the rubber adhesive layer 70 is in the range of 72 or more and 78 or less, then there is an excessively large difference in rubber hardness between the rubber adhesive layer 70 and the cover rubber 6d of the frame 6 due to the hardness of the rubber adhesive layer 70 being excessively hard is weakened, the stress concentration between the frame 6 and the bead core 21 can be relieved more effectively. As a result, damage such as rupture of the carcass cord 6c can be more effectively prevented while preventing delamination between the rubber adhesive layer 70 and the carcass 6. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

Moreover, in the portions of the rubber adhesive layer 70 and the rubber reinforcing layer 60 located on the inner side of the bead core 21 in the tire lateral direction, the outer end portion 71 of the rubber adhesive layer 70 is located further on the outer side in the tire radial direction than the outer end portion 61 rubber reinforcement layer 60, and thus the rubber reinforcement layer 60 can be prevented from contacting the frame 6. As a result, the sulfur component from the cover rubber 6d of the frame 6 can be prevented from leaking into the rubber reinforcement layer 60, and the adhesive component in the cover rubber 6d can be prevented from being reduced carcass 6. Thus, delamination between the cover rubber 6d and the carcass cord 6c can be more effectively prevented.

In addition, by placing the outer end portion 71 of the rubber adhesive layer 70 further on the outer side in the radial direction of the tire than the outer end portion 61 of the rubber reinforcing layer 60, it is possible to prevent a sharp change in stiffness between the rubber reinforcing layer 60 having a high rubber hardness and the carcass. 6. In other words, by placing the outer end portion 71 of the rubber adhesive layer 70 further on the outer side in the radial direction of the tire than the outer end portion 61 of the rubber reinforcing layer 60, and forming a stepped shape, the difference in stiffness between the area near the outer end portion 61 of the rubber reinforcing layer layer 60 and surrounding elements can be reduced. As a result, delamination caused by the presence of a region having a large difference in stiffness with adjacent elements can be prevented. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

In addition, since the outer end portion 61 of the rubber reinforcing layer 60 in the tire radial direction is located further on the outer side in the tire radial direction than the outer circumferential surface 22 of the bead core 21, the rubber reinforcing layer 60 can be located in a wider range between the bead core 21 and the carcass 6. Thus, the stress concentration under the action of a large force between the carcass 6 and the bead core 21 can be more effectively weakened by the rubber reinforcing layer 60, and damage such as breaking of the carcass cord 6c can be prevented more effectively. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

In addition, since the rubber adhesive layer 70 contains a cobalt compound, the adhesive ability of the rubber adhesive layer 70 can be improved. As a result, the rubber adhesive layer 70 can enhance the adhesive ability to both the frame 6 and the rubber reinforcing layer 60, and delamination can be more effectively prevented when the rubber reinforcing layer 60 has a rubber hardness higher than the rubber hardness of surrounding members. . As a result, the wear resistance of the bead portion 20 can be improved more effectively.

In addition, since the shortest distance between the bead wire 28 and the carcass cord 6c is in the range of 4 mm or more to 8 mm or less, it is possible to more effectively prevent tearing of the carcass cord 6c while preventing delamination between the carcass 6 and surrounding members. In other words, when the shortest distance between the bead wire 28 and the carcass cord 6c is less than 4 mm, the shortest distance between the bead wire 28 and the carcass cord 6c is excessively small. Therefore, it may be difficult to reduce the stress concentration between the frame 6 and the bead core 21 when a large force is applied between the frame 6 and the bead core 21. In this case, it may be difficult to effectively prevent the carcass cord 6c from breaking due to the force acting between the carcass 6 and the bead core 21. In addition, when the shortest distance between the bead wire 28 and the carcass cord 6c is more than 8 mm, the shortest distance between the bead wire 28 and the carcass cord 6c is excessively large, and thus the carcass 6 may be displaced excessively easily. In this case, since the frame 6 is excessively displaced due to the force acting on the frame 6, delamination between the frame 6 and surrounding members may occur.

On the contrary, when the shortest distance between the bead wire 28 and the carcass cord 6c is in the range of 4 mm or more and 8 mm or less, the stress concentration between the carcass 6 and the bead core 21 can be more effectively weakened while preventing excessive displacement of the carcass 6 As a result, damage such as rupture of the carcass cord 6c can be more effectively prevented while delamination between the carcass 6 and surrounding members is prevented. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

In addition, since the rubber hardness of the rubber reinforcing layer 60 ranges from 80 or more to 85 or less, rupture of the carcass cord 6c can be more effectively prevented while preventing delamination between the rubber reinforcing layer 60 and surrounding members. In other words, in the case where the hardness of the rubber of the rubber reinforcing layer 60 is less than 80, the hardness of the rubber of the rubber reinforcing layer 60 is excessively small, and thus it may be difficult to relieve the stress concentration between the frame 6 and the bead core 21. In this case, it may be difficult to effectively prevent the carcass cord 6c from breaking due to the force acting between the carcass 6 and the bead core 21. In addition, when the rubber hardness of the rubber reinforcing layer 60 is more than 85, the rubber hardness of the rubber reinforcing layer 60 is excessively large, and thus the difference in rubber hardness between the rubber reinforcing layer 60 and the inner organic fiber reinforced layer 50 may be excessively large. In this case, there is a possibility that delamination is likely to occur due to an excessively large difference in rubber hardness between the rubber reinforcing layer 60 and the inner organic fiber reinforced layer 50.

On the other hand, when the rubber hardness of the rubber reinforcing layer 60 is in the range of 80 or more and 85 or less, then there is an excessively large difference in rubber hardness between the rubber reinforcing layer 60 and the inner organic fiber reinforced layer 50 due to the hardness of the rubber rubber the reinforcing layer 60 being excessively hard is weakened, the stress concentration between the frame 6 and the bead core 21 can be weakened more effectively. As a result, damage such as breaking of the carcass cord 6c can be more effectively prevented while delamination between the rubber reinforcing layer 60 and the inner organic fiber-reinforced layer 50 is prevented. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

In addition, since the hardness of the rubber of the rubber reinforcing layer 60 is equal to or higher than the hardness of the rubber of the bead filler 40, the hardness of the rubber of the rubber reinforcing layer 60 can be more effectively ensured. Moreover, the force acting between the frame 6 and the bead core 21 can be more effectively dispersed by the rubber reinforcing layer 60, having a high hardness of rubber. Thus, wear of the cover rubber 6d due to the force acting between the carcass 6 and the bead core 21 can be more effectively prevented, and damage such as breaking of the carcass cord 6c can be more effectively prevented. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

Second embodiment

The pneumatic tire 1 according to the second embodiment has a configuration substantially similar to that of the pneumatic tire 1 according to the first embodiment, but has the design feature that the outer organic fiber reinforced layer 80 is disposed on the outer side of the rubber reinforcing layer 60 Since other configurations are identical to those of the first embodiment, descriptions thereof will be omitted and identical reference numbers will be used.

In FIG. 5 is a meridional cross-sectional view illustrating a main portion of the pneumatic tire 1 according to the second embodiment. Similar to the pneumatic tire 1 according to the first embodiment, the pneumatic tire 1 according to the second embodiment is a radial construction vehicle tire called an OR tire. In the pneumatic tire 1 according to the second embodiment, a pair of bead portions 20 are located on both sides of the tire equatorial plane CL in the tire lateral direction, and a bead core 21 is located in each of the pair of bead portions 20. Additionally, the carcass 6 extends between the bead core portions 20 on both sides in the tire transverse direction, and the carcass 6 is positioned to extend through the inner side of the bead core 21 in the tire radial direction from the inner side of the bead core 21 in the tire transverse direction of the bead portion 20 and is folded in reverse side to the outside in the transverse direction of the tire.

In FIG. 6 is a detailed view of portion C shown in FIG. 5. Similar to the first embodiment, the bead core 21 is configured to have a substantially hexagonal cross-sectional shape when viewed from a meridional cross-section of the tire. Specifically, the bead core 21 is formed such that the lower portion 23 of the bead core corresponding to the inner annular surface of the bead core 21 and the outer annular surface 22 of the bead core in the overall view of the bead core 21 are substantially parallel to each other, and the bead core 21 is formed in locations on respective end sides in the tire lateral direction in a substantially hexagonal shape having corner portions projecting in the tire lateral direction, the lower bead core portion 23 being the inner annular surface of the bead cores 21 as viewed through the entire bead core 21, and has corner portions projecting in the tire lateral direction at locations at certain locations on both sides in the tire lateral direction.

The inner organic fiber reinforced layer 50 and the rubber reinforcing layer 60 are disposed on the bead portion 20, and the inner organic fiber reinforced layer 50 is wound around the bead core 21 around the entire circumference of the bead core 21 in the meridional cross section of the tire. On the other hand, unlike the first embodiment, in the second embodiment, the rubber reinforcing layer 60 is wound around the entire circumference of the bead core 21 in the meridional cross section of the tire on the outer side of the inner organic fiber-reinforced layer 50 between the inner organic fiber-reinforced layer 50 and the carcass 6. Thus, in the meridional cross section of the tire, when the direction approaching the center of gravity of the bead core 21 is defined as the inner side direction when starting from the bead core 21, and the direction away from the center of gravity of the bead core 21 is defined as the outer side direction when starting from bead core 21, the rubber reinforcing layer 60 is located on the outer side of the inner organic fiber-reinforced layer 50 from the bead core 21.

Moreover, in the second embodiment, unlike the first embodiment, the rubber adhesive layer 70 is not located in the bead portion 20, but the outer organic fiber-reinforced layer 80 is located in the bead portion 20. The outer organic fiber reinforced layer 80 is located at least between the rubber reinforcing layer 60 and the carcass 6, extends through the tire radial inner side of the bead core 21 from the inner side of the bead core 21 in the tire transverse direction, and is positioned to extend to the outer side of the core. 21 beads in the transverse direction of the tire. In the second embodiment, the outer organic fiber reinforced layer 80 is wound around the entire circumference of the bead core 21 in the meridional cross section of the tire from the outer side of the rubber reinforcing layer 60.

In FIG. 7 is an explanatory diagram illustrating a state in which the inner organic fiber-reinforced layer 50, the rubber reinforcement layer 60 and the outer organic fiber-reinforced layer 80 shown in FIG. 6, wound around the core 21 sides. Similar to the first embodiment, the inner organic fiber-reinforced layer 50 wound around the bead core 21 is formed by spirally winding the inner organic fiber-reinforced material 55, which is a ribbon-like member, around the bead core 21 extending in the circumferential direction of the tire.

The rubber reinforcing layer 60, which is wound around the entire circumference of the bead core 21 on the outer side of the inner organic fiber reinforced layer 50, is formed by spirally winding the rubber reinforcing material 65 in the form of a band-like element around the bead core 21 extending in the circumferential direction of the tire on the outer side inner organic fiber-reinforced material 55. In other words, in the rubber reinforcing layer 60, the rubber reinforcing material 65 is helically wound around the bead core 21, around which the inner organic fiber-reinforced material 55 is wound, with the outer side of the inner organic fiber-reinforced material 55 along the longitudinal direction of the core 21 beads, with a bead core 21 extending in a circumferential direction of the tire as the center of the helix. Here, the rubber reinforcing material 65 is helically wound, and adjacent annular portions are in contact with each other. For example, the rubber reinforcing material 65 is wound, and portions of the adjacent annular portions in the transverse direction of the rubber reinforcing material 65 formed in a tape-like shape are overlapped. As a result, the rubber reinforcing material 65 is wound without play over the entire outer side of the inner organic fiber-reinforced material 55 in the bead core 21, around which the inner organic fiber-reinforced material 55 is wound.

The outer organic fiber-reinforced layer 80 wound around the entire circumference of the bead core 21 on the outer side of the rubber reinforcing layer 60 is formed by spirally winding the outer organic fiber-reinforced material 85, which is a ribbon-like member, around the bead core 21 extending in the circumferential direction of the tire. on the outer side of the rubber reinforcing material 65. In other words, in the outer organic fiber reinforced layer 80, the outer organic fiber reinforced material 85 is helically wound around the bead core 21, around which the rubber reinforcing material 65 is wound, on the outer side of the rubber reinforcing material 65 along the longitudinal direction of the core 21 beads with a bead core 21 extending in the circumferential direction of the tire as the center of the helix. Here, the inner organic fiber reinforced material 85 is helically wound and adjacent annular portions are in contact with each other. For example, the outer organic fiber-reinforced material 85 is wound, and portions of the adjacent annular portions in the transverse direction of the outer organic fiber-reinforced material 85 formed in a tape-like shape are overlapped. As a result, the outer organic fiber reinforced material 85 is wound without play over the entire outer side of the rubber reinforcing material 65 in the bead core 21 around which the rubber reinforcing material 65 is wound.

In the inner organic fiber reinforced layer 50, the rubber reinforcing layer 60 and the outer organic fiber reinforced layer 80, the direction in which the inner organic fiber reinforced material 55 is helically wound, the direction in which the rubber reinforcement material 65 is helically wound, and the direction in which the outer organic fiber reinforced material 55 is helically wound. organic fiber material 85 is spirally wound, match.

Similar to the first embodiment, the inner organic fiber-reinforced layer 50 is formed by covering the cover rubber 52 with an organic fiber cord 51, which is a cord member made of an organic fiber-based material such as aramid, nylon, polyester or rayon. In other words, in the inner organic fiber reinforced layer 50, the inner organic fiber reinforced material 55 is helically wound around the bead core 21, and thus the organic fiber cord 51 is also helically wound around the bead core 21. The cover rubber 52 completely covers the plurality of organic fiber cords 51 to hold the plurality of organic fiber cords 51 as a unit.

Likewise, the outer organic fiber-reinforced layer 80 is formed by covering the cover rubber 82 with an organic fiber cord 81, which is a cord member made of an organic fiber-based material. In other words, in the outer organic fiber-reinforced layer 80 in the form of the outer organic fiber-reinforced material 85 in the form of a tape-shaped element, a plurality of organic fiber cords 81 extending in the length direction of the outer organic fiber-reinforced material 85 are arranged in parallel order, and the cover rubber 82 completely covers a plurality of organic fiber cords 81 to hold the plurality of organic fiber cords 81 as a unit. In addition, since the organic fiber cord 81 is arranged to extend in the length direction of the outer organic fiber-reinforced material 85, with the outer organic fiber-reinforced material 85 helically wound on the outside of the rubber reinforcing layer 60, the organic fiber cord 81 is also helically wound around bead core 21, around which an internal organic fiber-reinforced layer 50 and a rubber reinforcing layer 60 are wound.

The rubber reinforcing material 65 forming the rubber reinforcing layer 60 located between the inner organic fiber-reinforced layer 50 and the outer organic fiber-reinforced layer 80 is a band-shaped rubber member. Thus, the rubber reinforcing layer 60 formed by spirally winding the rubber reinforcing material 65 is a rubber member wound around the outer side of the inner organic fiber-reinforced layer 50 and located between the inner organic fiber-reinforced layer 50 and the outer organic fiber-reinforced layer 80. Hardness The rubber of the rubber reinforcing layer 60 is higher, for example, than the hardness of the rubber cover rubber 52 of the inner organic fiber-reinforced layer 50 and the hardness of the cover rubber 82 of the outer organic fiber-reinforced layer 80, and also higher than the hardness of the rubber cover rubber 6d of the frame 6. The hardness of the rubber rubber reinforcement layer 60 equal to or higher than the hardness of the rubber of the bottom filler 41 of the filler 40 of the side. In the second embodiment, similar to the first embodiment, the rubber reinforcing layer 60 has a rubber hardness in the range of 80 or more and 85 or less. Further, in the second embodiment, similar to the first embodiment, the hardness of the rubber is the JIS-A hardness expressed in rubber hardness units in accordance with the JIS K6253 standard.

The inner organic fiber reinforced layer 50 located on the inner side of the rubber reinforcing layer 60 and the outer organic fiber reinforced layer 80 located on the outer side of the rubber reinforcing layer 60 include organic fiber cords 51 and 81, respectively, and a cord thickness 81 of organic fiber of the outer organic fiber-reinforced layer 80 is equal to or greater than the thickness of the organic fiber cord 51 of the inner organic fiber-reinforced layer 50. The thickness of the organic fiber cord 81 of the outer organic fiber-reinforced layer 80 is preferably in the range of 1.0 times or more to 2.5 times or less the thickness of the organic fiber cord 51 of the inner organic fiber-reinforced layer 50. Specifically, the linear density of the organic fiber cord 51 of the inner organic fiber-reinforced layer 50 is in the range of 700 dtex or more and 2000 dtex or less, and the linear density of the organic fiber cord 81 of the organic fiber-reinforced layer 80 is in the range of 700 dtex or more and up to 2000 dtex or less.

The hardness of the cover rubber 82 of the outer organic fiber-reinforced layer 80 is equal to or greater than the hardness of the cover rubber 52 of the inner organic fiber-reinforced layer 50. Specifically, the cover rubber 52 of the inner organic fiber-reinforced layer 50 has a rubber hardness in the range of 65 or more and 75. or less, and the cover rubber 82 of the outer organic fiber-reinforced layer 80 has a rubber hardness in the range of 70 or more and 80 or less.

In FIG. 8 is a detailed view of portion D shown in FIG. 6. The inner organic fiber reinforced layer 50, the rubber reinforcing layer 60 and the outer organic fiber reinforced layer 80 are arranged between the bead core 21 and the frame 6. Among them, the inner organic fiber reinforced layer 50 has a thickness Wi ranging from 1 mm or more to 3 mm or less. The rubber reinforcing layer 60 has a thickness Wr ranging from 1 mm or more to 8 mm or less, and the outer organic fiber reinforced layer 80 has a thickness Wo ranging from 1 mm or more to 3 mm or less.

Since the corresponding members between the bead core 21 and the frame 6 are formed to have the specified thickness values, the shortest distance between the bead wire 28 provided by the bead core 21 and the carcass cord 6c provided by the frame 6 is in the range of 3 mm or more to 10 mm or less. The bead core 21 is configured to have a substantially hexagonal cross-sectional shape as a shape in the meridional cross-section of the tire. Thus, the shortest distance between the bead wire 28 provided by the bead core 21 and the carcass cord 6c provided by the carcass 6 is the distance between the bead wire 28 located on any of the corner portions of the bead core 21 formed in a substantially hexagonal cross-sectional shape. , and a carcass cord 6c provided by the carcass 6.

Thus, the distance between the bead wire 28 located on the corner portion of the bead core 21, which projects outwardly when viewed from the center side in the cross-sectional shape of the bead core 21, and the carcass cord 6c of the carcass 6 is 3 mm or more at any corner plot. Accordingly, for example, the distance between the innermost point 26 of the bead core and the carcass cord 6c provided by the carcass 6 is also 3 mm or more. It should be noted that the shortest distance between the bead wire 28 and the carcass cord 6c is preferably in the range of 4 mm or more and 8 mm or less.

In the case where the pneumatic tire 1 configured as described above is mounted on a vehicle, similar to the pneumatic tire 1 according to the first embodiment, the pneumatic tire 1 is mounted on the specified rim R and the pneumatic tire 1 is mounted on the wheel rim. After mounting on the rim, the pneumatic tire 1 is inflated, and the inflated pneumatic tire 1 is installed on the vehicle.

During movement of a vehicle having pneumatic tires 1 mounted on it, each part of the pneumatic tire 1 experiences loads acting in different directions. Since the pneumatic tire 1 according to the second embodiment is mounted on a large vehicle and is used under heavy load conditions, the sidewall portions 5 and the frame 6 bear a very large load. Thus, a large tensile force is exerted on the frame 6, and the frame 6 rubs against the innermost point 26 of the bead core or the like. bead core 21, thereby applying a large load to it, and as a result, damage such as rupture of the carcass cord 6c may occur.

On the other hand, in the pneumatic tire 1 according to the second embodiment, the inner organic fiber reinforced layer 50 is wound around the bead core 21, and the rubber reinforcing layer 60 covering at least the innermost point 26 of the bead core is disposed between the inner organic fiber reinforced layer. 50 and the frame 6. Thus, even when there is a large force between the frame 6 and the bead core 21 due to the large tensile force acting on the frame 6, this force acting between the frame 6 and the bead core 21 can be dispersed by the rubber reinforcing layer 60, possessing elasticity and high hardness of rubber. In this way, wear of the cover rubber 6d due to the force acting between the carcass 6 and the bead core 21 can be prevented, and damage such as breaking of the carcass cord 6c can be prevented.

In addition, since the outer organic fiber-reinforced layer 80 is located between the rubber reinforcement layer 60 and the frame 6, and the rubber reinforcement layer 60 is covered with the outer organic fiber-reinforced layer 80, the flow of the rubber reinforcement layer 60 from the location between the frame 6 and the bead core 21 during molding vulcanization of the pneumatic tire 1 can be prevented. Accordingly, the force acting between the carcass 6 and the bead core 21 can be more effectively dispersed by the rubber reinforcing layer 60, and damage such as breaking of the carcass cord 6c can be more effectively prevented. As a result, the wear resistance of the bead portion 20 can be improved.

In addition, since the hardness of the rubber of the rubber reinforcing layer 60 is equal to or higher than the hardness of the rubber of the cover rubber 52 of the inner organic fiber-reinforced layer 50 and the cover rubber 82 of the outer organic fiber-reinforced layer 80, the force acting between the carcass 6 and the bead core 21 can be more effective. dispersed by a rubber reinforcing layer 60, which has a high rubber hardness. As a result, wear of the cover rubber 6d of the carcass 6 due to the force acting between the carcass 6 and the bead core 21 can be more effectively prevented, and damage such as breaking of the carcass cord 6c can be prevented. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

In addition, since the thickness of the organic fiber cords 81 of the outer organic fiber-reinforced layer 80 is equal to or greater than the thickness of the organic fiber cords 51 of the inner organic fiber-reinforced layer 50, the winding force of the outer organic fiber-reinforced layer 80 relative to the bead core 21 can be more effectively provided. As a result, the bead wires 28 forming the bead core 21 can be more effectively prevented from being separated by the outer organic fiber-reinforced layer 80, and the shape of the bead core 21 can be more effectively prevented from flattening when a large force is applied to the bead core 21. In addition, since the organic fiber cords 81 of the outer organic fiber-reinforced layer 80 are thick, leakage of the rubber reinforcing layer 60 to the outer side of the outer organic fiber-reinforced layer 80 during mold vulcanization of the pneumatic tire 1 can be more effectively prevented by the outer organic fiber-reinforced layer 80. At this time, the force acting between the frame 6 and the bead core 21 can be more effectively dispersed by the rubber reinforcing layer 60. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

In addition, since the hardness of the cover rubber 82 of the outer organic fiber-reinforced layer 80 is equal to or higher than the hardness of the cover rubber 52 of the inner organic fiber-reinforced layer 50, the winding force of the outer organic fiber-reinforced layer 80 relative to the bead core 21 can be more effectively ensured and can be more efficiently prevent separation of the bead wires 28 forming the bead core 21. In addition, since the hardness of the cover rubber 82 of the outer organic fiber-reinforced layer 80 is high, leakage of the rubber reinforcement layer 60 to the outer side of the outer organic fiber-reinforced layer 80 during mold vulcanization of the pneumatic tire 1 can be more effectively prevented by the outer organic fiber-reinforced layer. 80. At this time, the force acting between the frame 6 and the bead core 21 can be more effectively dispersed by the rubber reinforcing layer 60. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

In addition, the outer organic fiber-reinforced layer 80 is formed by helically winding the outer organic fiber-reinforced material 85, and the outer organic fiber-reinforced material 85 is helically wound, and adjacent annular portions are in contact with each other. Thus, it is possible to more effectively prevent the rubber reinforcing layer 60 from leaking out from the space between the carcass 6 and the bead core 21 during mold vulcanization of the pneumatic tire 1. In other words, when there is a gap in the spiral wound outer organic fiber reinforced material 85, there is a possibility of the rubber reinforcing material leaking out. layer 60 from this gap. However, when the outer organic fiber-reinforced material 85 is wound helically and adjacent annular portions are adjacent to each other or overlapped, the existence of a gap in the outer organic fiber-reinforced material 85 can be prevented. As a result, when mold vulcanizing the pneumatic tire 1, leakage of the rubber reinforcing layer can be prevented. 60 located on the inner side of the outer organic fiber-reinforced material 85, from a gap in the outer organic fiber-reinforced material 85, and flowing from a position between the frame 6 and the bead core 21, and the rubber reinforcing layer 60 can be more effectively located between the frame 6 and the core. 21 sides. Accordingly, the force acting between the carcass 6 and the bead core 21 can be more effectively dispersed by the rubber reinforcing layer 60, and damage such as breaking of the carcass cord 6c can be more effectively prevented. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

Moreover, in the inner organic fiber reinforced layer 50 and the outer organic fiber reinforced layer 80, since the direction in which the inner organic fiber reinforced material 55 is helically wound is the same as the direction in which the outer organic fiber reinforced material 85 is helically wound, the inner organic fiber reinforced material The fiber material 55 and the outer organic fiber reinforced material 85 can be wound without gap more efficiently. As a result, it can be prevented from having a gap on both the inner side and the outer side of the rubber reinforcing layer 60, and the rubber reinforcing layer 60 can be more effectively prevented from leaking out from the space between the carcass 6 and the bead core 21 during mold vulcanization of the pneumatic tire 1. Thus , the rubber reinforcing layer 60 can be more effectively disposed between the carcass 6 and the bead core 21, and damage such as breaking of the carcass cord 6c can be more effectively prevented. As a result, the wear resistance of the bead portion 20 can be improved more effectively.

Modified examples

In the pneumatic tire 1 according to the above-described first embodiment, the outer end portions 61 of the rubber reinforcing layer 60 in the tire radial direction are located further on the outer side in the tire radial direction than the outer circumferential surface 22 of the bead core 21 on both the inner side and the outer side. core 21 beads in the transverse direction of the tire. However, the outer end portion 61 of the rubber reinforcing layer 60 need not be located further on the outer side in the radial direction of the tire than the outer circumferential surface 22 of the bead core 21.

In FIG. 9 shows a modified example of the pneumatic tire 1 according to the first embodiment, and is an explanatory diagram of a state in which the outer end portion 61 of the rubber reinforcing layer 60 on the outer side in the tire lateral direction is located further on the inner side in the tire radial direction than the outer circumferential surface 22 cores 21 sides. In FIG. 10 shows a modified example of the pneumatic tire 1 according to the first embodiment, and is an explanatory diagram of a state in which the outer end portion 61 of the rubber reinforcing layer 60 on the inner side in the lateral direction of the tire is located further on the inner side in the radial direction of the tire than the outer circumferential surface 22 cores 21 sides. In the rubber reinforcing layer 60 of the pneumatic tire 1 according to the first embodiment, for example, as shown in FIG. 9, the outer end portion 61 located on the inner side of the bead core 21 in the tire lateral direction may be located further on the outer side in the tire radial direction than the outer annular surface 22 of the bead core 21 and the outer end portion 61 of the bead core 21 in the lateral direction. the tire direction may be located further on the inner side in the tire radial direction than the outer circumferential surface 22 of the bead core 21. In this case, the outer end portion 61 on the side located on the outer side of the bead core 21 in the tire lateral direction in the rubber reinforcing layer 60 is preferably located further on the outer side in the tire radial direction than the outermost point 27 of the bead core of the bead core 21.

Conversely, as shown in FIG. 10, in the rubber reinforcing layer 60 of the pneumatic tire 1 according to the first embodiment, the outer end portion 61 located on the outer side of the bead core 21 in the tire lateral direction may be located further on the outer side in the tire radial direction than the outer circumferential surface 22 bead core 21, and the outer end portion 61 of the bead core 21 in the tire transverse direction may be located further on the inner side in the tire radial direction than the outer circumferential surface 22 of the bead core 21. In this case, likewise, the outer end portion 61 on the side located on the inner side of the bead core 21 in the tire lateral direction in the rubber reinforcing layer 60 is preferably located further on the outer side in the tire radial direction than the innermost point 26 of the bead core of the bead core 21 sides.

In FIG. 11 shows a modified example of the pneumatic tire 1 according to the first embodiment, and is an explanatory diagram of a state in which the outer end portions 61 of the rubber reinforcing layer 60 on both sides in the tire lateral direction are located further on the inner side in the tire radial direction than the outer circumferential surface 22 cores 21 sides. Moreover, as shown in FIG. 11, in the rubber reinforcing layer 60 of the pneumatic tire 1 according to the first embodiment, the outer end portions 61 located on both sides of the bead core 21 in the tire lateral direction may be located further on the inner side in the tire radial direction than the outer circumferential surface 22 core 21 sides. In this case, similarly, the outer end portion 61 on the side located on the inner side of the bead core 21 in the tire transverse direction in the rubber reinforcing layer 60 is preferably located further on the outer side in the tire radial direction than the innermost point 26 of the bead core of the bead core 21 sides. The outer end portion 61 on the side located on the outer side of the bead core 21 in the tire lateral direction is preferably located further on the outer side in the tire radial direction than the outermost point 27 of the bead core of the bead core 21.

As described above, the outer end portions 61 located on both sides of the bead core 21 in the tire lateral direction in the rubber reinforcing layer 60 only need to be located further on the outer side in the tire radial direction than at least the innermost point 26 of the bead core and the most outer point 27 of the bead core of the bead core 21. Thus, the rubber reinforcing layer 60 may cover the area from the innermost point 26 of the bead core to the outermost point 27 of the bead core in the bead core 21, and therefore concentrate stresses at a location where stress concentrations are likely to occur between the core 21 sides and frame 6, can be weakened.

In other words, the bead core 21 is formed to have a substantially hexagonal cross-sectional shape, and the frame 6 extends through the inner side of the bead core 21 in the tire radial direction from the inner side of the bead core 21 in the tire transverse direction and is folded back toward the outer side. side in the transverse direction of the tire. Thus, by covering the area from the innermost point 26 of the bead core to the outermost point 27 of the bead core with the rubber reinforcing layer 60, the portion covered by the frame 6 at the corner portion in the cross-sectional shape of the bead core 21 can be covered with the rubber reinforcing layer 60 located between the core 21 of the side and the frame 6.

As a result, the rubber reinforcing layer 60 can weaken the stress concentration near the corner portion in the cross-sectional shape of the bead core 21, which is a portion in which the stress concentration is likely to occur between the bead core 21 and the frame 6. Thus, easy wear can be prevented cover rubber 6d due to stress concentration and more effectively prevent the carcass cord 6c from breaking. As a result, the wear resistance of the bead portion 20 can be improved.

In the pneumatic tire 1 according to the first embodiment described above, the shape of the bead core 21 in the meridional cross section of the tire is a substantially hexagonal cross-sectional shape, however, the bead core 21 may be formed into a shape other than this. In FIG. 12 shows a modified example of the pneumatic tire 1 according to the first embodiment, and is an explanatory diagram for the case where the cross-sectional shape of the bead core 21 is octagon-shaped. For example, as shown in FIG. 12, the bead core 21 of the pneumatic tire 1 according to the first embodiment can be formed so as to have a substantially octagonal cross-sectional shape in the meridional cross-section of the tire. In the case where the bead core 21 is formed with a substantially octagonal cross-sectional shape, when the innermost side in the tire transverse direction is formed along the tire radial direction, both of the two corner portions located at both ends of the side represent the innermost points 26 of the bead core 21 sides. Likewise, in the case where the bead core 21 is formed with a substantially octagonal cross-sectional shape, when the outermost side in the tire transverse direction is formed along the tire radial direction, both of the two corner portions located at both ends of the side represent the outermost points 27 bead core 21 bead core.

Thus, when the sides on both sides of the bead core 21 in the tire lateral direction are formed in the tire radial direction, the rubber reinforcing layer 60 of the pneumatic tire 1 according to the first embodiment is preferably arranged to cover the area on the sides of both sides of the bead core 21 in transverse direction of the tire. Thus, the rubber reinforcing layer 60 may cover the two innermost points 26 of the bead core and the two outermost points 27 of the bead core. Because of this, the rubber reinforcing layer 60 can more effectively relieve the stress concentration in the area where the stress is likely to be concentrated between the bead core 21 formed with a substantially octagonal cross-sectional shape and the frame 6. Therefore, damage to the frame 6 can be prevented due to for stress concentrations, and the wear resistance of the bead portion 20 can be improved.

Moreover, in the pneumatic tire 1 according to the second embodiment described above, the rubber reinforcing layer 60 is located around the entire circumference of the bead core 21 in the meridional cross section of the tire, but the rubber reinforcing layer 60 need not be located around the entire circumference of the bead core 21 .

In FIG. 13 shows a modified example of the pneumatic tire 1 according to the second embodiment, and is an explanatory diagram of a state in which the rubber reinforcing layer 60 is disposed from the inner side of the bead core 21 in the tire lateral direction to the outer side in the tire lateral direction. In FIG. 14 shows a modified example of the pneumatic tire 1 according to the second embodiment, and is an explanatory diagram of a state in which the rubber reinforcing layer 60 is disposed on the inner side of the bead core 21 in the tire lateral direction. For example, as shown in FIG. 13, in the meridional cross section of the tire, the rubber reinforcing layer 60 of the pneumatic tire 1 according to the second embodiment may be arranged to extend through the inner side of the bead core 21 in the tire radial direction from the inner side of the bead core 21 in the tire transverse direction to the outer side of the core. 21 beads in the transverse direction of the tire. In other words, the rubber reinforcing layer 60 may be arranged by reversing the sheet rubber member from the inside of the tire cross-direction bead core 21 to the outer side of the tire cross-direction bead core 21 rather than spirally winding the tape-like rubber reinforcing material 65 (see . Fig. 7) around the core 21 sides. In this case, on the outer side of the inner organic fiber-reinforced layer 50, the portion in which the rubber reinforcing layer 60 is not located is in a state in which the outer organic fiber-reinforced layer 80 is directly located on the outer side of the inner organic fiber-reinforced layer 50.

Alternatively, as shown in FIG. 14, the rubber reinforcing layer 60 of the pneumatic tire 1 according to the second embodiment can only be located in a portion on the inner side of the bead core 21 in the tire lateral direction. In this case, similarly, a rubber sheet member can be used as the rubber reinforcing layer 60, and the rubber reinforcing layer 60 can be located on the inner side of the bead core 21 in the tire lateral direction from a location further on the outer side in the tire radial direction than the outer ring surface 22 of the bead core 21 to a location further on the inner side in the radial direction of the tire than the bottom portion 23 of the bead core. The rubber reinforcing layer 60 need not be located around the entire circumference of the bead core 21 and must be located only between the inner organic fiber-reinforced layer 50 and the frame 6 to cover at least the innermost point 26 of the bead core.

Since the portion between the innermost point 26 of the bead core and the frame 6 is a portion in which stress concentration is likely to occur when a large tensile force is applied to the frame 6, stress concentration can be prevented by placing the rubber reinforcing layer 60 in such a manner that to cover at least the innermost point 26 of the bead core. As a result, wear of the cover rubber 6d can be prevented due to the force acting between the carcass 6 and the bead core 21, and damage such as breaking of the carcass cord 6c can be prevented. As a result, the wear resistance of the bead portion 20 can be improved.

Moreover, in the pneumatic tire 1 according to the second embodiment described above, the outer organic fiber-reinforced layer 80 is located around the entire circumference of the bead core 21 in the meridional cross-section of the tire, however, the outer organic fiber-reinforced layer 80 need not be located throughout core circumference 21 sides. In FIG. 15 shows a modified example of the pneumatic tire 1 according to the second embodiment, and is an explanatory diagram of a state in which the outer organic fiber-reinforced layer 80 is disposed from the inner side of the bead core 21 in the tire lateral direction to the outer side in the tire lateral direction. For example, as shown in FIG. 15, in the meridional cross section of the tire, the outer organic fiber reinforced layer 80 of the pneumatic tire 1 according to the second embodiment may be arranged to extend through the inner side of the bead core 21 in the tire radial direction from the inner side of the bead core 21 in the tire transverse direction to the outer side side of the core 21 beads in the transverse direction of the tire. In other words, as shown in FIG. 15, both the outer organic fiber reinforced layer 80 and the rubber reinforcing layer 60 can be arranged by reversing the folding from the inner side of the bead core 21 in the tire lateral direction to the outer side of the bead core 21 in the tire lateral direction.

The outer organic fiber reinforced layer 80 should be located only at least between the rubber reinforcing layer 60 and the carcass 6 and extend through the inside of the bead core 21 in the tire radial direction from the inside of the bead core 21 in the tire transverse direction to the outside of the bead core 21 in in the transverse direction of the tire. Since the outer organic fiber-reinforced layer 80 is located between the rubber reinforcement layer 60 and the carcass 6, leakage of the rubber reinforcement layer 60 from the position between the bead core 21 and the carcass 6 during mold vulcanization of the pneumatic tire 1 can be prevented by the outer organic fiber-reinforced layer 80. As a result, the force acting between the carcass 6 and the bead core 21 can be more effectively dispersed by the rubber reinforcing layer 60, damage such as breaking of the carcass cord 6c can be prevented, and therefore the wear resistance of the bead portion 20 can be improved.

In the pneumatic tire 1 according to the second embodiment described above, the shape of the bead core 21 in the meridional cross section of the tire is a substantially hexagonal cross-sectional shape, however, the bead core 21 may be formed into a shape other than this. In FIG. 16 shows a modified example of the pneumatic tire 1 according to the second embodiment, and is an explanatory diagram for the case where the cross-sectional shape of the bead core 21 is octagon-shaped. For example, as shown in FIG. 16, the bead core 21 of the pneumatic tire 1 according to the second embodiment may also be formed to have a substantially octagonal cross-sectional shape in the meridional cross-section of the tire, and the inner organic fiber reinforced layer 50, the rubber reinforcing layer 60 and the outer reinforced organic fiber layer 80 may be arranged to be wound around a bead core 21 having a substantially octagonal cross-sectional shape. In the pneumatic tire 1 according to the second embodiment, in the case where the bead core 21 is formed with a substantially octagonal cross-sectional shape, when the innermost side in the tire lateral direction is formed along the tire radial direction, both of two corner portions located at both ends sides, represent the innermost points 26 of the bead core of the bead core 21.

Thus, when the side located on the innermost side of the bead core 21 in the tire lateral direction is formed along the tire radial direction, the rubber reinforcing layer 60 of the pneumatic tire 1 according to the second embodiment is preferably arranged to cover at least two innermost points 26 of the bead core. As a result, the rubber reinforcing layer 60 can more effectively relieve the stress concentration in the area where the stress is likely to concentrate between the bead core 21 formed with a substantially octagonal cross-sectional shape and the frame 6. Therefore, damage to the frame 6 due to stress concentrations, and the wear resistance of the bead portion 20 can be improved.

Moreover, in the pneumatic tires 1 according to the first and second embodiments described above, one layer is arranged as the inner organic fiber-reinforced layer 50, but the inner organic fiber-reinforced layer 50 can be arranged by superimposing a plurality of layers. Similarly, in the pneumatic tire 1 according to the second embodiment described above, one layer is arranged as the outer organic fiber-reinforced layer 80, but the outer organic fiber-reinforced layer 80 may be arranged by superposing multiple layers.

Moreover, in the pneumatic tire 1 according to the first embodiment described above, only one bead core 21 is disposed in one bead portion 20, but a plurality of bead cores 21 may be disposed in one bead portion 20. In FIG. 17 shows a modified example of the pneumatic tire 1 according to the first embodiment, and provides an explanatory diagram for the case where a plurality of bead cores 21 are disposed in the bead portion 20. As shown in FIG. 17, for example, three bead cores 21 of the pneumatic tire 1 according to the first embodiment may be arranged in one bead portion 20. In this case, the frame 6 extends through the inner side of the bead core 21 in the tire radial direction from the inner side of the bead core 21 in the tire lateral direction and is folded back toward the outer side in the tire lateral direction for each of the bead cores 21. In other words, the pneumatic tire 1 according to the first embodiment may be configured as a bias tire comprising carcasses 6 including bias ply cords. When laying multiple frames 6, different frames 6 can be reversed for each of the bead cores 21 in the bead section 20.

As described above, when a plurality of bead cores 21 are arranged in one bead portion 20 of the pneumatic tire 1 according to the first embodiment and a plurality of frames 6 are reverse-wrapped for each of the bead cores 21, the inner organic fiber reinforced layer 50, the rubber reinforcing layer 60 and a rubber adhesive layer 70 are provided for each of the bead cores 21. In other words, the inner organic fiber-reinforced layer 50 may be wound around each of a plurality of bead cores 21 disposed in one bead portion 20, and a rubber reinforcing layer 60 and a rubber adhesive layer 70 may be disposed between each of the inner organic fiber-reinforced layers 50 and each of the frames 6.

Even in the case where a plurality of bead cores 21 are arranged in one bead portion 20, when a large load is applied to the pneumatic tire 1 and a large tensile force is applied to the carcass 6, damage to the carcass 6 due to friction between the carcass 6 and the bead core 21 may occur in each of the bead cores 21. frames 6. Thus, when a plurality of bead cores 21 are arranged in one bead portion 20 and a plurality of frames 6 are reversed for each of the bead cores 21, the inner organic fiber reinforced layer 50, the rubber reinforcement layer 60 and the rubber adhesive layer 70 are also placed for each of the bead cores 21, which can prevent damage to each of the frames 6. As a result, the wear resistance of the bead portion 20 can be improved by placing a plurality of bead cores 21 in one bead portion 20.

Similarly, in the pneumatic tire 1 according to the second embodiment, a plurality of bead cores 21 may be arranged in one bead portion 20. In FIG. 18 shows a modified example of the pneumatic tire 1 according to the second embodiment, and is an explanatory diagram for the case where a plurality of bead cores 21 are arranged in the bead portion 20. Likewise, as shown in FIG. 18, for example, three bead cores 21 of the pneumatic tire 1 according to the second embodiment may be arranged in one bead portion 20. In other words, similar to the second embodiment, the pneumatic tire 1 can be configured as a bias tire containing carcasses 6 including bias ply cords. When laying multiple frames 6, different frames 6 can be reversed for each of the bead cores 21 in the bead section 20.

As described above, when a plurality of bead cores 21 are arranged in one bead portion 20 of the pneumatic tire 1 according to an embodiment and a plurality of frames 6 are reverse-wrapped for each of the bead cores 21, the inner organic fiber reinforced layer 50, the rubber reinforcing layer 60 and a second outer organic fiber reinforced layer 80 is provided for each of the bead cores 21. Even in the case where a plurality of bead cores 21 are arranged in one bead portion 20, when a large load is applied to the pneumatic tire 1 and a large tensile force is applied to the carcass 6, damage to the carcass 6 due to friction between the carcass 6 and the bead core 21 may occur in each of the bead cores 21. frames 6. Thus, when a plurality of bead cores 21 are arranged in one bead portion 20 and a plurality of frames 6 are reversed for each of the bead cores 21, the inner organic fiber reinforced layer 50, the rubber reinforcing layer 60 and the outer organic fiber reinforced layer 80 are also arranged for each of the bead cores 21, which can prevent damage to each of the frames 6. As a result, the wear resistance of the bead portion 20 can be improved by placing a plurality of bead cores 21 in one bead portion 20.

Examples

In FIG. 19A and FIG. 19B presents tables showing the results of the first test to evaluate the performance of pneumatic tires. In FIG. 20A and FIG. 20B presents tables showing the results of the second test to evaluate the performance of pneumatic tires. Next, with respect to the above-described pneumatic tire 1, the first and second performance evaluation tests conducted on the pneumatic tires of the exemplary examples, the pneumatic tire 1 according to the embodiments of the present invention, and the pneumatic tires of the comparative examples will be described in comparison with the pneumatic tires 1 in in accordance with embodiments of the present invention. In the first and second performance evaluation tests, wear resistance tests were performed to evaluate the wear resistance of the pneumatic tire 1.

In the first and second performance evaluation tests, pneumatic tire 1 having a nominal size of 46/90R57 was used as the test tire. The test tire was mounted on a TRA rim, the air pressure was adjusted to the TRA air pressure, and the tire was tested loaded using the TRA load.

Among the evaluation elements in the first and second performance evaluation tests in the wear resistance evaluation method using an indoor drum testing machine with a load set to 85% of the maximum load specified in the TRA standard and a speed set to 15 km/h, after After running the pneumatic tire for 30 days set as the target running time, the wear resistance test was stopped and evaluated based on the degree of damage to the carcass in the bead section and whether there was a break in the carcass cord in the bead section. The presence of carcass cord breakage in the bead portion was verified by peeling off the carcass and bead core in the bead portion of the pneumatic tire after a run test in an indoor drum testing machine, confirming the extent of damage and breakage of the carcass cord and confirming the presence of a carcass cord breakage determination. The degree of damage to the carcass in the bead portion, which indicates the wear resistance of the bead portion, was evaluated by indexing the degree of damage and breaking of the carcass cord, and expressed the reciprocal of the index value as an index, assigning the following Typical Example 1 a value of 100 in the first performance evaluation test and in as an index, assigning the following Typical Example 2 a value of 100 in the second performance evaluation test.

Performance evaluation tests were carried out on 15 types of pneumatic tires, including the pneumatic tire of the generic example 1 corresponding to the example of the generic pneumatic tire, Examples 1-1 to 1-12 corresponding to the pneumatic tire 1 according to the embodiments of the present invention, and comparative examples 1-1 and 1-2, corresponding to pneumatic tires for comparison with pneumatic tires 1 according to embodiments of the present invention. Among them, in the pneumatic tire of Typical Example 1, although the inner organic fiber reinforced layer is wound around the bead core, the rubber reinforcing layer or the rubber adhesive layer is not located in the bead portion. In the pneumatic tire of Comparative Example 1-1, although the rubber reinforcing layer and the rubber adhesive layer are located in the bead portion, the hardness of the rubber of the rubber reinforcing layer does not exceed the hardness of the rubber of the rubber adhesive layer or the hardness of the covering rubber of the inner organic fiber reinforced layer, and the shortest distance between the bead wire and frame cord is not 3 mm or more. In the pneumatic tire of Comparative Example 1-2, although the rubber reinforcing layer and the rubber adhesive layer are placed in the bead portion, the rubber reinforcing layer does not cover the innermost point of the bead core.

On the other hand, in all of Examples 1-1 to 1-12, which are examples of pneumatic tires 1 according to embodiments of the present invention, rubber reinforcing layers 60 are located in the bead portions 20, with rubber reinforcing layers 60 covering the innermost points 26 of the bead core, and the shortest distance between the bead wires 28 and the carcass cords 6c is 3 mm or more. In addition, the corresponding pneumatic tires 1 according to Examples 1-1 to 1-12 are distinguished by the rubber hardness of the rubber reinforcing layer 60, the rubber hardness of the rubber adhesive layer 70, and whether the outer end portion 71 of the rubber adhesive layer 70 is in the radial direction tires further than the outer end portion 61 of the rubber reinforcing layer 60 in the tire radial direction, differ in whether the outer end portion 61 of the rubber reinforcing layer 60 in the tire radial direction is further on the outer side in the tire radial direction than the bead core 21, and differ whether the rubber adhesive layer 70 contains a cobalt compound.

As a result of performance evaluation tests using pneumatic tires 1, as shown in FIG. 19A and 19B, it is found that the pneumatic tires 1 according to Examples 1-1 to 1-12 have a degree of damage to the bead portions 20 less than that of the Typical Example 1 and Comparative Examples 1-1 and 1-2, and the occurrence of carcass ruptures Cords 6c in sections 20 beads are less likely. The pneumatic tires 1 according to Examples 1-1 to 1-12 can provide improved wear resistance of the bead portion 20.

The second performance evaluation test was carried out on 16 types of pneumatic tires, including the pneumatic tire according to Typical Example 2 corresponding to the example of the generic pneumatic tire, Examples 2-1 to 2-14 corresponding to pneumatic tires 1 according to embodiments of the present invention , and Comparative Example 2 corresponding to a pneumatic tire for comparison with the pneumatic tire 1 according to embodiments of the present invention. Among them, in the pneumatic tire of Typical Example 2, although the inner organic fiber-reinforced layer is wound around the bead core, the rubber reinforcing layer or the outer organic fiber-reinforced layer is not provided, and the shortest distance between the bead wire and the carcass cord is 1 mm. In the pneumatic tire of Comparative Example 2, although the inner organic fiber reinforced layer is wound around the bead core, no rubber reinforcing layer or outer organic fiber reinforced layer is provided, and the shortest distance between the bead wire and the carcass cord is 3 mm.

In contrast, Examples 2-1 to 2-14, which are examples of pneumatic tires 1 according to embodiments of the present invention, all contain inner organic fiber-reinforced layers 50, rubber reinforcing layers 60, and outer organic fiber-reinforced layers 80 in portions 20 sides. In addition, the corresponding pneumatic tires 1 according to Examples 2-1 to 2-14 are characterized by the shortest distance between the bead wire 28 and the carcass cord 6c, differ in whether the hardness of the rubber of the rubber reinforcing layer 60 is equal to or higher than the hardness of the rubber of the cover rubber 52 of the inner reinforced organic fiber layer 50 or the hardness of the rubber of the covering rubber 72 of the outer organic fiber-reinforced layer 80, is equal to or higher than the hardness of the rubber of the rubber reinforcing layer 60 of the hardness of the rubber of the filler 40 beads, differing in the hardness of the rubber reinforcing layer 60, differing in whether the outer organic fiber-reinforced layers 80 are wound such that adjacent annular portions are in contact with each other, differ in whether the helical winding directions of the outer organic fiber-reinforced layer 50 and the outer organic fiber-reinforced layer 80 are the same, differ in whether the thickness of the organic fiber cord 81 is equal to the outer organic fiber-reinforced layer 80 thickness of the organic fiber cord 51 of the inner organic fiber-reinforced layer 50, and differ in whether the rubber hardness of the cover rubber 72 of the outer organic fiber-reinforced layer 80 is equal to or greater than the hardness of the rubber of the cover rubber 52 of the inner organic fiber-reinforced layer 50.

As a result of performance evaluation tests using pneumatic tires 1, as shown in FIG. 20A and 20B, it is found that the pneumatic tires 1 according to Examples 2-1 to 2-14 have a degree of damage to the bead portions 20 less than that of the Typical Example 2 and Comparative Example 2, and also the occurrence of breaks in the carcass cords 6c in the portions 20 sides is less likely. The pneumatic tires 1 according to Examples 2-1 to 2-14 can provide improved wear resistance of the bead portions 20.

List of reference items

1 - pneumatic tire

2 - tread section

3 - contact surface of the tread

4 - shoulder section

5 - sidewall section

6 - frame

6a - section of the frame body

6b - section curved upward

6c - frame cord

6d - lining rubber

7 - breaker layer

8 - containment layer

10 - running section

20 - side section

21 - bead core

22 - outer annular surface

23 - lower part of the bead core

26 - the innermost point of the bead core

27 - the outermost point of the bead core

28 - bead wire

30 - main bead section of the tire

40 - side filler

50 - internal layer reinforced with organic fiber

51 - organic fiber cord

52 - lining rubber

55 - internal organic fiber reinforced material

60 - rubber reinforcing layer

61 - outer end section

65 - rubber reinforcing material

70 - rubber adhesive layer

71 - outer end section

80 - outer layer reinforced with organic fiber

81 - organic fiber cord

82 - lining rubber

85 - outer organic fiber reinforced material

Claims (32)

1. A pneumatic tire containing: a pair of bead sections located on both sides of the equatorial plane of the tire in the transverse direction of the tire; bead cores located in the bead portions, the bead cores being formed by winding bead wires into a ring and having a shape in the meridional cross section of the tire formed with a polygonal cross section; a frame extending between bead portions on both sides in the tire lateral direction, the frame extending through the inner side of the bead core in the tire radial direction from the inner side of the bead core in the tire lateral direction and folded back toward the outer side in the tire lateral direction in the bead portion , wherein the carcass is formed by covering the carcass cord with a covering rubber; an inner organic fiber reinforced layer wound around a bead core and formed by covering the organic fiber cord with a cover rubber; And a rubber reinforcing layer located between the inner organic fiber reinforced layer and the carcass so as to cover at least the apex on the innermost side of the bead core in the lateral direction of the tire, wherein the shortest distance between the bead wire and the carcass cord is 3 mm or more. 2. Pneumatic tire according to claim 1, in which the rubber reinforcing layer is arranged to extend through the inner side of the bead core in the tire radial direction from the inner side of the bead core in the tire transverse direction to the outer side of the bead core in the tire transverse direction, a rubber adhesive layer is disposed between the rubber reinforcing layer and the carcass so as to extend through the inner side of the bead core in the tire radial direction from the inner side of the bead core in the tire lateral direction to the outer side of the bead core in the tire lateral direction, the rubber adhesive layer has a rubber hardness equal to or higher than the rubber hardness of the carcass covering rubber, the rubber reinforcing layer has a rubber hardness equal to or higher than the rubber hardness of the rubber adhesive layer and the rubber hardness of the covering rubber of the inner organic fiber-reinforced layer, and the rubber adhesive layer has a sulfur content equal to or greater than the sulfur content of the carcass lining rubber. 3. The pneumatic tire according to claim 2, wherein the rubber adhesive layer has a rubber hardness in the range of 72 or more and 78 or less. 4. The pneumatic tire according to claim 2 or 3, wherein in portions located on the inner side of the bead core in the tire transverse direction of the rubber adhesive layer and the rubber reinforcing layer, an end portion on the outer side of the rubber adhesive layer in the tire radial direction is located further on the outer side in the tire radial direction than the end portion on the outer side of the rubber reinforcing layer in the tire radial direction. 5. Pneumatic tire according to any one of paragraphs. 2-4, in which the rubber reinforcing layer has an end portion on the outer side in the tire radial direction located further on the outer side in the tire radial direction than the outer circumferential surface of the bead core. 6. Pneumatic tire according to any one of paragraphs. 2-5, in which the rubber adhesive layer contains a cobalt compound. 7. The pneumatic tire according to claim 1, comprising an outer organic fiber reinforced layer formed by covering the organic fiber cord with a cover rubber, wherein the outer organic fiber reinforced layer is located at least between the rubber reinforcing layer and the carcass, wherein the outer organic fiber reinforced layer located so as to extend through the inner side of the bead core in the tire radial direction from the inner side of the bead core in the tire transverse direction to the outer side of the bead core in the tire transverse direction. 8. The pneumatic tire according to claim 7, wherein the rubber reinforcing layer has a rubber hardness equal to or higher than the hardness of the rubber of the inner organic fiber-reinforced layer cover rubber and the outer organic fiber-reinforced layer cover rubber. 9. The pneumatic tire according to claim 7 or 8, wherein the organic fiber cord of the outer organic fiber-reinforced layer has a thickness equal to or greater than the thickness of the organic fiber cord of the inner organic fiber-reinforced layer. 10. Pneumatic tire according to any one of paragraphs. 7-9, wherein the cover rubber of the outer organic fiber-reinforced layer has a rubber hardness equal to or higher than the rubber hardness of the cover rubber of the inner organic fiber-reinforced layer. 11. Pneumatic tire according to any one of paragraphs. 7-10, in which the outer organic fiber-reinforced layer is formed by spirally winding a tape-like member around a bead core extending in the circumferential direction of the tire, and the tape-shaped element is wound helically, and at the same time adjacent annular sections are in contact with each other. 12. Pneumatic tire according to claim 11, in which the inner organic fiber-reinforced layer is formed by spirally winding a tape-like member around a bead core extending in the circumferential direction of the tire, and in the inner organic fiber-reinforced layer and the outer organic fiber-reinforced layer, the direction in which the tape-like element forming the inner fiber-reinforced layer is helically wound is the same as the direction in which the tape-like element forming the outer organic fiber-reinforced layer is helically wound. 13. Pneumatic tire according to any one of paragraphs. 1-12, in which the shortest distance between the bead wire and the carcass cord is in the range of 4 mm or more and 8 mm or less. 14. Pneumatic tire according to any one of paragraphs. 1-13, wherein the rubber reinforcing layer has a rubber hardness in the range of 80 or more and 85 or less. 15. Pneumatic tire according to any one of paragraphs. 1-14, in which the bead filler is located on the inner side of the folded portion in the tire lateral direction and the outer side of the bead core in the tire radial direction, and the beaded portion is a portion folded back toward the outer side of the bead core in the tire lateral direction in the casing, and the rubber reinforcing layer has a rubber hardness equal to or higher than the rubber hardness of the bead filler.