JPWO2020090680A1 - tire - Google Patents

Abstract

The bead portion (60) of the pneumatic tire (10) includes a bead structure having a bead core composed of a predetermined number of cord units arranged adjacent to each other along the tire width direction and the tire radial direction. The cord unit includes a bead cord formed of a metal material and a coating resin formed of a resin material and coating the bead cord. The cord unit is a convex polygon of a quadrangle or more, and the inner end portion of the bead structure in the tire radial direction is inclined outward in the tire radial direction from the center of the bead structure in the tire width direction toward the outer side in the tire width direction. Including inclined parts.

Description

The present invention relates to a tire in which a part of the bead portion is formed of a resin material.

Conventionally, a tire in which a resin is filled in a gap portion of a bead core is known (see Patent Document 1).

As a result, the amount of metal bead cords can be reduced, which makes it possible to reduce the weight of tires.

Japanese Unexamined Patent Publication No. 2002-187414

It has been studied to further develop the technique of using resin for a part of the bead portion as described above, and to form a bead core by winding a cord unit in which the bead cord is coated with a resin material a plurality of times along the tire circumferential direction. There is.

According to such a method for forming a bead core, by arranging cord units having a rectangular cross section adjacent to each other, a gap is not formed between the cord units, and a bead core having high rigidity and light weight can be easily manufactured.

On the other hand, when such a bead core is used, there are the following problems. Specifically, since the bead structure surrounding the bead core has a square shape (square shape) along the shape of the bead core, the movement of the carcass ply in the manufacturing process is restricted.

In particular, when vulcanizing a raw tire, the position of the carcass ply is displaced relative to other constituent members such as a bead structure including a bead core (referred to as ply slip) to obtain a desired tire shape. However, the movement of the carcass ply is regulated by the corners of the bead structure, and it is difficult to induce ply slip.

Further, even after production, so-called fretting may occur in which the carcass ply is rubbed and damaged by the corners of the bead structure.

Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to provide a tire having both ease of manufacture and durability while using a cord unit in which a bead cord is coated with a resin material. ..

One aspect of the present invention is a tread portion in contact with a road surface, a tire side portion connected to the tread portion and located inside the tread portion in the tire radial direction, and a tire side portion connected to the tire side portion, and the tire diameter of the tire side portion. A tire including a bead portion located inside in the direction, and the bead portion is arranged adjacent to each other along the tire width direction and the tire radial direction in a cross section along the tire width direction and the tire radial direction. The cord unit includes a bead structure having a bead core composed of a number of cord units, the cord unit including a bead cord and a coating resin formed of a resin material and covering the bead cord, in a tire width direction and a tire diameter. In a cross section along the direction, the cord unit is a convex polygon of a quadrangle or more, and the inner end portion of the bead structure in the tire radial direction is directed from the center of the bead structure in the tire width direction to the outside in the tire width direction. Includes an inclined portion that inclines outward in the radial direction of the tire.

FIG. 1 is a cross-sectional view of the pneumatic tire 10. FIG. 2 is a partially enlarged cross-sectional view of the pneumatic tire 10. FIG. 3 is an enlarged cross-sectional view of the bead structure 61. FIG. 4 is a single cross-sectional view of the bead core 62. FIG. 5 is an explanatory diagram of a method of configuring the bead core 62. FIG. 6 is an enlarged cross-sectional view of the bead structure 61X according to the modified example. FIG. 7 is an enlarged cross-sectional view of the bead structure 61Y according to another modified example.

Hereinafter, embodiments will be described with reference to the drawings. The same functions and configurations are designated by the same or similar reference numerals, and the description thereof will be omitted as appropriate.

(1) Overall Schematic Configuration of Tire FIG. 1 is a cross-sectional view of a pneumatic tire 10 according to the present embodiment. Specifically, FIG. 1 is a cross-sectional view of the pneumatic tire 10 along the tire width direction and the tire diameter direction. In FIG. 1, the cross-sectional hatching is not shown (the same applies hereinafter).

As shown in FIG. 1, the pneumatic tire 10 includes a tread portion 20, a tire side portion 30, a carcass ply 40, a belt layer 50, and a bead portion 60.

The tread portion 20 is a portion in contact with the road surface (not shown). A pattern (not shown) is formed on the tread portion 20 according to the usage environment of the pneumatic tire 10 and the type of vehicle to be mounted.

The tire side portion 30 is connected to the tread portion 20 and is located inside the tread portion 20 in the tire radial direction. The tire side portion 30 is a region from the outer end of the tread portion 20 in the tire width direction to the upper end of the bead portion 60. The tire side portion 30 is sometimes called a sidewall or the like.

The carcass ply 40 forms the skeleton of the pneumatic tire 10. The carcass ply 40 has a radial structure in which carcass cords (not shown) arranged radially along the tire radial direction are covered with a rubber material. However, the structure is not limited to the radial structure, and a bias structure in which the carcass cords are arranged so as to intersect in the tire radial direction may be used.

Further, the carcass cord is not particularly limited, and can be formed by an organic fiber cord in the same manner as a general passenger car tire.

The belt layer 50 is provided inside the tread portion 20 in the tire radial direction. The belt layer 50 is a single-layer spiral belt having a reinforcing cord 51 and the reinforcing cord 51 being coated with a resin. However, the belt layer 50 is not limited to the single-layer spiral belt. For example, the belt layer 50 may be a two-layer interlaced belt coated with rubber.

As the resin covering the reinforcing cord 51, a rubber material constituting the tire side portion 30 and a resin material having a higher tensile elastic modulus than the rubber material constituting the tread portion 20 are used. As the resin for coating the reinforcing cord 51, an elastic thermoplastic resin, a thermoplastic elastomer (TPE), a thermosetting resin, or the like can be used. Considering the elasticity during running and the moldability during manufacturing, it is desirable to use a thermoplastic elastomer.

Examples of the thermoplastic elastomer include polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), and polyester-based thermoplastic elastomer (TPC). , Dynamically crosslinked thermoplastic elastomer (TPV) and the like.

Examples of the thermoplastic resin include polyurethane resin, polyolefin resin, vinyl chloride resin, and polyamide resin. Further, as a thermoplastic resin material, for example, the deflection temperature under load (at a load of 0.45 MPa) specified in ISO75-2 or ASTM D648 is 78 ° C or higher, and the tensile yield strength specified in JIS K7113 is 10 MPa or higher. Similarly, those having a tensile fracture elongation of 50% or more specified in JIS K7113 and a Bikat softening temperature (method A) specified in JIS K 7206 of 130 ° C. or more can be used.

The bead portion 60 is connected to the tire side portion 30 and is located inside the tire side portion 30 in the tire radial direction. The bead portion 60 is an annular shape extending in the tire circumferential direction.

A part of the bead portion 60 is made of a resin material appropriately selected from the above-mentioned resin materials. In the present embodiment, a part of the bead portion 60 is formed of the same resin material as the resin material used for the belt layer 50 described above.

The bead portion 60 is locked to a flange portion 110 (not shown in FIG. 1, see FIG. 2) formed at the radial outer end of the rim wheel 100.

In addition, an inner liner (not shown) that prevents air (or gas such as nitrogen) from leaking into the internal space of the pneumatic tire 10 assembled to the rim wheel 100 is provided on the inner surface of the pneumatic tire 10. It is pasted.

(2) Schematic configuration of the bead portion FIG. 2 is a partially enlarged cross-sectional view of the pneumatic tire 10. Specifically, FIG. 2 is a partially enlarged cross-sectional view of the pneumatic tire 10 including the bead portion 60 along the tire width direction and the tire diameter direction.

As shown in FIG. 2, the bead portion 60 includes a bead structure 61.

The carcass ply 40 is folded back outward in the tire width direction via the bead portion 60. Specifically, the carcass ply 40 includes a main body portion 41 and a folded portion 42. The bead structure 61 includes a bead core 62 (not shown in FIG. 2, see FIG. 3) and is annular along the tire circumferential direction.

The main body portion 41 is provided over the tread portion 20, the tire side portion 30, and the bead portion 60, and is a portion until the bead portion 60, specifically, the bead structure 61 is folded back.

The folded-back portion 42 is a portion connected to the main body portion 41 and folded outward in the tire width direction via the bead structure 61.

(3) Detailed configuration of bead portion FIG. 3 is an enlarged cross-sectional view of the bead structure 61. As shown in FIG. 3, in the bead structure 61, the bead core 62 (including the peripheral portion of the bead core 62) and the bead filler 66 are integrally formed. That is, the bead portion 60 has a bead core 62 and a bead filler 66. The bead filler 66 does not necessarily have to be formed integrally with the bead core 62, and may be formed as a separate body.

The bead core 62 is composed of a predetermined number of cord units arranged adjacent to each other along the tire width direction and the tire radial direction. In the present embodiment, the bead core 62 is composed of a cord unit 63A, a cord unit 63B, a cord unit 63C, and a cord unit 63D. That is, in the present embodiment, the bead core 62 is composed of four (predetermined number) cord units in the cross section along the tire width direction and the tire radial direction.

Further, the inner end portion of the bead structure 61 in the tire radial direction includes an inclined portion 61s that inclines outward in the tire radial direction from the center of the bead structure 61 in the tire width direction toward the outer side in the tire width direction. That is, the inner end portion of the bead structure 61 in the tire radial direction is convex toward the inner side in the tire radial direction.

FIG. 4 is a single cross-sectional view of the bead core 62. As shown in FIG. 4, each of the cord units 63A to 63D contains a bead cord 64 and a coating resin 65. The bead cord 64 is formed of a metallic material (eg, steel). That is, the bead core 62 is formed using a metal material. The bead cord 64 may be formed of organic fibers, carbon fibers or inorganic fibers instead of the bead cord 64.

The coating resin 65 is formed of a resin material. The resin material used for the bead structure 61 excluding the coating resin 65 and the bead core 62 may be the same as the resin material used for the belt layer 50.

Further, the resin material used for the coating resin 65 and the resin material used for the bead structure 61 excluding the bead core 62 may be different as long as they are the above-mentioned resin materials that can be used for the belt layer 50.

In the present embodiment, the code units 63A to 63D are convex polygons having a quadrangle or more in a cross section along the tire width direction and the tire radial direction. Specifically, the cord units 63A to 63D are diamond-shaped in the cross section along the tire width direction and the tire radial direction. Each of the apex 63p of the diamond-shaped code units 63A to 63D is chamfered.

The bead core 62 formed by a plurality of cord units preferably has as few gaps as possible between adjacent cord units, and the cord units adopt a cross-sectional shape that does not form such gaps.

Each of the code units 63A to 63D contains two bead codes 64. The two bead cords 64 are arranged so as to be parallel to any side of the diamond-shaped cord units 63A to 63D. That is, each of the code units 63A to 63D includes a plurality of bead codes 64 arranged in parallel with any side of the rhombus.

FIG. 5 is an explanatory diagram of a method of configuring the bead core 62. As shown in FIG. 5, each of the cord units 63A to 63D in which the bead cord 64 is coated with the coating resin 65 is actually two consecutive cord units, and the two cord units are used around the tire. It is wound multiple times (twice) along the direction.

Specifically, the code unit 63A and the code unit 63C are one continuous code unit. Similarly, the code unit 63B and the code unit 63D are one continuous code unit.

As shown in FIG. 5, first, the cord unit 63A and the cord unit 63B corresponding to the first stage are wound in an annular shape, and then the cord unit 63C and the cord unit 63D corresponding to the second stage are wound in an annular shape. ..

Alternatively, the cord unit 63A and the cord unit 63B, and the cord unit 63C and the cord unit 63D are made into one continuous cord unit, and first, the cord unit 63B and the cord unit 63D corresponding to the first stage are wound in a ring shape. Next, the cord unit 63A and the cord unit 63C corresponding to the second stage may be wound in an annular shape.

(4) Action / Effect According to the above-described embodiment, the following action / effect can be obtained. Specifically, the cord unit 63A to the cord unit 63D include a bead cord 64 formed of a metal material and a coating resin 65 formed of a resin material and covering the bead cord 64.

The cord unit 63A to the cord unit 63D are convex polygons of a quadrangle or more, and the inner end portion of the bead structure 61 in the tire radial direction is oriented from the center of the bead structure 61 in the tire width direction to the outer side in the tire width direction. Includes an inclined portion 61s that inclines outward in the tire radial direction.

Therefore, when the pneumatic tire 10 is vulcanized in the state of a raw tire, it is possible to allow the relative misalignment of the carcass ply 40 with respect to other components (bead core 62, etc.), and the pneumatic tire 10 It becomes easy to obtain the desired tire shape of.

Further, since the bead structure 61 is formed with the inclined portion 61s, it is possible to prevent the carcass ply 40 from being rubbed and damaged.

That is, according to the pneumatic tire 10, it is possible to achieve both ease of manufacture and durability while using the cord unit 63A to the cord unit 63D in which the bead cord 64 is coated with the resin material.

In this embodiment, the cross-sectional shapes of the cord unit 63A to the cord unit 63D are rhombic. Therefore, when the bead core 62 is configured, no gap is formed between the adjacent cord units, and the rigidity of the bead core 62 can be increased. Thereby, the durability of the pneumatic tire 10 can be enhanced.

Further, when one cord unit is wound to form the bead core 62, it can be easily stacked. That is, the ease of manufacturing can be improved.

Further, in the present embodiment, each of the code unit 63A to the code unit 63D includes a plurality of bead codes 64 arranged in parallel with any side of the rhombus. Therefore, it is easy to secure the required rigidity of the cord unit as a whole. Thereby, the durability of the pneumatic tire 10 can be enhanced.

In this embodiment, the apex 63p of the code unit is chamfered. Therefore, when the cord unit is wound to form the bead core 62, interference with the adjacent cord unit can be suppressed. In addition, damage to the apex 63p can be suppressed. Thereby, the ease of manufacture and the durability can be improved.

(5) Other Embodiments Although the contents of the present invention have been described above with reference to the examples, the present invention is not limited to these descriptions, and various modifications and improvements are possible. It is self-evident to the trader.

For example, in the above-described embodiment, the cross-sectional shapes of the cord units 63A to 63D are rhombic, but they may be changed as follows.

FIG. 6 is an enlarged cross-sectional view of the bead structure 61X according to the modified example. As shown in FIG. 6, the bead structure 61X includes a bead core 62X composed of a predetermined number (7) of cord units 63X. The cross-sectional shape of the cord unit 63X is a convex polygon, specifically, a hexagon (honeycomb shape).

FIG. 7 is an enlarged cross-sectional view of the bead structure 61Y according to another modified example. As shown in FIG. 7, the bead structure 61Y includes a bead core 62Y composed of a predetermined number (7) of cord units 63Y. The cross-sectional shape of the code unit 63Y is a quadrangle, specifically a square.

Further, in the bead structure 61X and the bead structure 61Y, the inclined portion 61s is formed similarly to the bead structure 61.

In addition, the cross-sectional shape of the cord unit may be a shape such as a rectangle or a parallelogram so that there is as little space as possible between adjacent cord units.

Further, in the above-described embodiment, the two bead cords 64 are arranged so as to be parallel to any side of the diamond-shaped cord units 63A to 63D, but the two bead cords 64 are arranged on the sides. Instead, they may be arranged so as to be parallel to the diagonal line.

Although embodiments of the invention have been described above, the statements and drawings that form part of this disclosure should not be understood to limit the invention. Various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art from this disclosure.

10 Pneumatic tires
20 tread section
30 Tire side
40 Car Casply
41 Main body
42 Folded part
50 belt layer
51 Reinforcement cord
60 bead part
61 bead structure
61s sloping part
61X, 61Y bead structure
62, 62X, 62Y bead core
63A, 63B, 63C, 63D, 63X, 63Y code unit
63p apex
64 bead code
65 Coating resin
66 bead filler
100 rim wheel
110 Flange part

Claims (5)

The tread part that touches the road surface and
A tire side portion connected to the tread portion and located inside the tread portion in the tire radial direction, and a tire side portion.
A tire that is connected to the tire side portion and includes a bead portion located inside the tire side portion in the tire radial direction.
In the cross section along the tire width direction and the tire radial direction, the bead portion is a bead structure having a bead core composed of a predetermined number of cord units arranged adjacently along the tire width direction and the tire radial direction. Including
The code unit is
Bead code and
Including a coating resin formed of a resin material and coating the bead cord.
In the cross section along the tire width direction and the tire diameter direction
The code unit is a convex polygon that is equal to or larger than a quadrangle.
The tire radial inner end portion of the bead structure is a tire including an inclined portion that inclines outward in the tire radial direction from the center of the bead structure in the tire width direction toward the outer side in the tire width direction. The tire according to claim 1, wherein the bead cord is formed by using a metal material. The tire according to claim 1 or 2, wherein the cord unit has a diamond shape in a cross section along the tire width direction and the tire diameter direction. The tire according to claim 3, wherein the cord unit includes a plurality of the bead cords arranged in parallel with any side of the rhombus. The tire according to any one of claims 1 to 4, wherein the apex portion of the cord unit is chamfered.

Images