WO2019244741A1

WO2019244741A1 - Pneumatic tire

Info

Publication number: WO2019244741A1
Application number: PCT/JP2019/023263
Authority: WO
Inventors: 崇之藏田
Original assignee: 株式会社ブリヂストン
Priority date: 2018-06-18
Filing date: 2019-06-12
Publication date: 2019-12-26
Also published as: JPWO2019244741A1

Abstract

A pneumatic tire 10 equipped with: a pair of bead cores 12A; a carcass 18 formed so as to span the interval between the pair of bead cores 12A; and a belt layer which has a ring-shaped resin main body 12B formed from a resin and positioned to the inside of the carcass 18 in the tire radial direction, and also has reinforcing cords 20A which are spirally wound at an angle which slants 5-20°, inclusive, relative to the tire circumferential direction and are embedded in the resin main body 20B with intervals interposed therebetween in the tire widthwise direction.

Description

Pneumatic tire

The present invention relates to a pneumatic tire provided with a belt layer.

A pneumatic tire to be mounted on an automobile includes two or more inclined belt plies including a cord inclined with respect to the tire circumferential direction on the outer side in the tire radial direction of the carcass, and a belt including a reinforcing layer and the like. (See, for example, Japanese Patent Application Laid-Open No. 2013-244930 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2013-220743 (Patent Document 2)).

The pneumatic tires of Patent Documents 1 and 2 have two or more inclined belt plies to secure in-plane shear rigidity. However, since the number of plies and reinforcing layers is large, it is difficult to reduce the weight of the tires. It has become.

The present invention has been made in consideration of the above-described circumstances, and has as its object to provide a pneumatic tire that ensures both in-plane shear rigidity of a belt and weight reduction of the tire.

The pneumatic tire according to the first aspect includes a pair of bead cores, a carcass formed over the pair of bead cores, and an annular resin body that is disposed outside the carcass in the tire radial direction and formed of resin. A belt layer having a reinforcing cord wound spirally at an inclination angle of 5 ° or more and 20 ° or less with respect to the tire circumferential direction and arranged at intervals in the tire width direction and embedded in the resin body. , Is provided.

空気 The pneumatic tire according to the first aspect includes a resin body and a belt layer having a reinforcing cord embedded in the resin body outside the carcass in the tire radial direction. In the belt layer, the reinforcing cords are spirally wound at an inclination angle of 5 ° or more and 20 ° or less with respect to the tire circumferential direction, and are arranged at intervals in the tire width direction.

By arranging the resin main body between the reinforcing cords as described above, it is possible to obtain a higher in-plane shear rigidity as compared with a case where rubber is arranged between the reinforcing cords, and it is possible to reduce the weight of the tire. .

Further, since the reinforcing cord is spirally wound at an inclination angle of 5 ° or more and 20 ° or less with respect to the tire circumferential direction, compared with the case where the reinforcing cord is arranged in parallel with the tire circumferential direction, The deformation of the belt layer in the tire circumferential direction is allowed. Therefore, a tensile force acts on the resin body of the belt layer in the tire circumferential direction due to the internal pressure of the tire, and a compressive force acts on the resin body in the tire width direction. Thereby, the tensile force in the tire width direction at the time of contact with the ground of the resin body of the belt layer is reduced, and tensile strain in the same direction can be suppressed. As a result, the durability of the belt layer can be improved.

は In the pneumatic tire according to the second aspect, the belt layer is formed by winding a resin-coated cord, in which the reinforcing cord is coated with a resin, outside the carcass in the tire radial direction.

According to the pneumatic tire according to the second aspect, the belt layer can be easily formed.

In the pneumatic tire according to the third aspect, the end face in the tire width direction of the reinforcing cord is coated with a resin.

According to the pneumatic tire according to the third aspect, it is possible to suppress water from entering the reinforcing cord.

According to the pneumatic tire of the present invention, it is possible to achieve both in-plane shear rigidity and weight reduction of the tire.

It is a sectional view showing the state where the pneumatic tire concerning this embodiment was cut along the tire width direction and the tire radial direction. FIG. 2 is a partial cross-sectional view illustrating a resin annular belt of the pneumatic tire according to the embodiment. FIG. 2 is a partially cutaway view of a resin annular belt of the pneumatic tire according to the embodiment. It is sectional drawing which shows the state which cut | disconnected the pneumatic tire which concerns on the modification of this embodiment along a tire width direction and a tire radial direction.

FIG. 1 shows a pneumatic tire 10 according to an embodiment of the present invention. The pneumatic tire 10 shows a radial tire as an example. In the drawings, arrow W indicates the tire width direction, and arrow R indicates the tire radial direction. Here, the tire width direction refers to a direction parallel to the rotation axis of the pneumatic tire 10. The tire radial direction refers to a direction orthogonal to the rotation axis of the pneumatic tire 10. Reference symbol CL indicates the equatorial plane of the tire 10 (tire equatorial plane).

In the present embodiment, the grounding end E of the tread 22 and the grounding width TW, which will be described later, mean that the pneumatic tire 10 is mounted on a standard rim specified in JATMA YEAR BOOK (2018 edition, Japan Automobile Tire Association Standard). Then, it is filled with 100% internal pressure of the air pressure (maximum air pressure) corresponding to the maximum load capacity (bold load in the internal pressure-load capacity correspondence table) in the applicable size ply rating in JATMA YEAR BOOK, This is one in which the rotation axis is arranged parallel to the flat plate and a mass corresponding to the maximum load capacity is added. When the TRA standard and the ETRTO standard are applied at the place of use or the place of manufacture, the respective standards are followed.

The pneumatic tire 10 includes a pair of bead portions 12 in which a bead core 12A is embedded, a pair of side portions 14 extending from the pair of bead portions 12 outward in the tire radial direction, and a crown portion 16 extending from the side portions 14 inward in the tire width direction. ,have. A carcass 18 composed of one carcass ply 18A straddles between one bead portion 12 and the other bead portion 12.

The inner liner 17 made of rubber is disposed inside the tire of the carcass 18. The side rubber layer 13 is disposed outside the carcass 18 in the tire width direction.

A resin annular belt 20 is disposed on the crown portion 16 on the outside of the carcass 18 in the tire radial direction. The resin annular belt 20 has an annular shape. The details of the resin annular belt 20 will be described later. A tread 22 is disposed outside the resin annular belt 20 in the tire radial direction. The tread 22 has a plurality of main grooves 22A formed along the tire circumferential direction.

As shown in FIGS. 2 and 3, the resin annular belt 20 has a reinforcing cord 20A spirally wound along the tire circumferential direction, and a resin main body 20B of a resin material covering the reinforcing cord 20A. I have. The resin annular belt 20 can be formed of a ring-shaped hoop in which a resin-coated cord 20C in which a reinforcing cord 20A is coated with a resin main body 20B is spirally wound and integrated. The resin-coated cord 20C is a long strip-shaped member in which a plurality of reinforcing cords 20A are arranged in parallel. In the present embodiment, the resin-coated cord 20C is configured such that ten reinforcing cords 20A are arranged in parallel and covered with a resin body 20B. .

The reinforcing cord 20A is arranged at an inclination angle θ with respect to the tire circumferential direction S, as shown in FIG. Is set to 5 ° or more and 20 ° or less. The angle θ is preferably 10 ° or more and 15 ° or less.

ゴム A resin material having a higher tensile modulus than the rubber material forming the side rubber layer 13 and the rubber material forming the tread 22 is used for the resin body 20B. The tensile modulus of the resin body 20B (defined in JIS K7113: 1995) is preferably 100 MPa or more. The upper limit of the tensile modulus of the resin main body 20B is preferably set to 1000 MPa or less. The tensile modulus of the resin body 20B is particularly preferably in the range of 200 to 700 MPa.

Examples of the material of the resin body 20B include general-purpose resins such as thermoplastic resins, thermoplastic elastomers, thermosetting resins, and (meth) acrylic resins, EVA resins, vinyl chloride resins, fluorine resins, and silicone resins. In addition, engineering plastics (including super engineering plastics) and the like can be used. The resin material here does not include vulcanized rubber.

A thermoplastic resin (including a thermoplastic elastomer) refers to a polymer compound in which a material softens and flows with an increase in temperature and becomes relatively hard and strong when cooled. In the present specification, among these materials, the material softens and flows with an increase in temperature, becomes a relatively hard and strong state when cooled, and a polymer compound having rubber-like elasticity is made into a thermoplastic elastomer, and the material with the increase in temperature becomes a material. Softens, flows, and becomes relatively hard and strong when cooled, and distinguishes a polymer compound having no rubber-like elasticity as a non-elastomer thermoplastic resin.

Examples of thermoplastic resins (including thermoplastic elastomers) include polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), and polyester Thermoplastic elastomer (TPC), dynamically crosslinked thermoplastic elastomer (TPV), polyolefin thermoplastic resin, polystyrene thermoplastic resin, polyamide thermoplastic resin, polyester thermoplastic resin, etc. No.

Thermosetting resin refers to a polymer compound that forms a three-dimensional network structure with a rise in temperature and cures, and examples thereof include a phenol resin, an epoxy resin, a melamine resin, and a urea resin.

It is preferable to use a reinforcing cord 20A that is thicker than the cord of the carcass ply 18A and has high strength (tensile strength). The reinforcing cord 20A can be composed of a monofilament (single wire) such as a metal fiber or an organic fiber, or a multifilament (stranded wire) obtained by twisting these fibers. In the present embodiment, the reinforcing cord 20A is a steel cord. The steel cord is mainly composed of steel, and can contain various trace contents such as carbon, manganese, silicon, phosphorus, sulfur, copper, and chromium.

環状 The resin annular belt 20 is formed with a constant diameter and a constant thickness, and is linear when viewed in a cross section along the tire axis. The resin annular belt 20 has an outer diameter at a central portion in the tire width direction larger than outer diameters at both end portions in the tire width direction. When viewed in a cross section along the tire axis, the central portion in the tire width direction has a tire. The shape may be a gentle arc that protrudes radially outward.

幅 The width BW of the resin annular belt 20 is preferably 75% or more and 110% or less with respect to the contact width TW (distance between the contact ends E) of the tread 22 measured along the tire axial direction.

(Action, effect)
Next, the operation and effect of the tire 10 of the present embodiment will be described.

クラウン In the tire 10 of the present embodiment, the crown portion 16 of the carcass 18 is reinforced by the resin annular belt 20. The resin annular belt 20 is formed by covering a reinforcing cord 20A with a resin main body 20B. Therefore, a higher in-plane shear rigidity can be obtained as compared with a belt in which rubber is disposed between the reinforcing cords. Further, the weight of the tire can be reduced.

By securing the in-plane shear rigidity of the resin annular belt 20, lateral force when a slip angle is given to the pneumatic tire 10 can be sufficiently generated, and steering stability can be secured. Also, the responsiveness can be improved.

In addition, the resin annular belt 20 secures out-of-plane bending rigidity, and when a large lateral force is applied to the pneumatic tire 10, buckling of the tread 22 (the surface of the tread 22 is wavy and a part of the tread 22 is separated from the road surface). Phenomenon).

Further, since the reinforcing cord 20A is spirally wound at an inclination angle of 5 ° or more and 20 ° or less with respect to the tire circumferential direction, it is compared with the case where the reinforcing cord 20A is arranged in parallel with the tire circumferential direction. Thus, deformation of the resin annular belt 20 in the tire circumferential direction is allowed. Therefore, a tensile force acts in the tire circumferential direction due to the internal pressure of the tire and a compressive force acts in the tire width direction on the resin main body 20B of the resin annular belt 20. Thereby, the tensile force in the tire width direction at the time of ground contact with the resin main body 20B of the resin annular belt 20 is reduced, and the tensile strain of the resin main body 20B in the same direction can be suppressed. As a result, the durability of the resin annular belt 20 can be improved.

As shown in FIG. 4, a resin layer 30 may be arranged outside the resin annular belt 20 in the tire width direction so as to cover the outer end surface. The resin layer 30 can be formed of the same material as the resin main body 20B. Both end surfaces in the tire width direction of the resin annular belt 20 are covered with a resin layer 30. By covering both end surfaces in the tire width direction of the resin annular belt 20 with the resin layer 30, it is possible to suppress water from entering the reinforcing cord 20A. Further, the rigidity step between the resin annular belt 20 and the tread 22 can be reduced.
Note that both end surfaces in the tire width direction of the resin annular belt 20 may be covered with a resin other than the resin layer 30. For example, the end face of the reinforcing cord 20A may be covered by melting the resin at both ends in the tire width direction of the resin annular belt 20.

The disclosure of Japanese Patent Application No. 2018-115417 filed on June 18, 2018 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned herein are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims

A pair of bead cores,
A carcass formed over the pair of bead cores,
An annular resin main body formed of resin, which is disposed outside the carcass in the tire radial direction, and wound spirally at an inclination angle of 5 ° or more and 20 ° or less with respect to the tire circumferential direction and in the tire width direction. A belt layer having reinforcing cords arranged at intervals in the resin body,
Pneumatic tire with.
2. The pneumatic tire according to claim 1, wherein the belt layer is formed by winding a resin-coated cord in which the reinforcing cord is coated with a resin around the carcass in the tire radial direction. 3.
The pneumatic tire according to claim 1 or 2, wherein an end face in the tire width direction of the reinforcing cord is coated with a resin.