WO2019230772A1

WO2019230772A1 - Pneumatic tire

Info

Publication number: WO2019230772A1
Application number: PCT/JP2019/021237
Authority: WO
Inventors: 啓之筆本
Original assignee: 株式会社ブリヂストン
Priority date: 2018-05-31
Filing date: 2019-05-29
Publication date: 2019-12-05
Also published as: JP2019209750A

Abstract

This pneumatic tire has provided on the tread section thereof: a resin annular body provided with reduced-diameter sections which are located at both end sections thereof in the tire width direction and which have an outer diameter decreasing toward outer ends in the tire width direction; and a resin-coated belt which is constituted of a resin-coated cord comprising a cord coated with a coating resin, the resin-coated cord being formed between the reduced-diameter sections at both end sections of the resin annular body in the tire width direction such that the resin-coated cord is wound helically on the outer surface of the resin annular body in the tire radial direction. The resin-coated belt is joined to the resin annular body, and the maximum thickness of both end sections of the resin annular body in the tire width direction is greater than the maximum thickness of the center section of the resin annular body in the tire width direction.

Description

Pneumatic tire

The present invention relates to a pneumatic tire.

Conventionally, an inclined belt including a metal cord inclined with respect to the tire circumferential direction on the outer side in the tire radial direction of the carcass disposed across the bead portions, and a circumference including a metal cord extending along the tire circumferential direction. There is known a pneumatic tire in which a belt including a directional belt is disposed.

Patent Document 1 discloses a carcass, an active reinforcing material composed of a single layer of reinforcing elements inclined by 4 ° to 7 ° with respect to the tire circumferential direction, and a flat surface positioned in the central portion of the crown of the carcass. A tire comprising a crown reinforcement comprising a circumferential polymer reinforcement element is disclosed.

Special table 2013-539734 gazette

According to the tire described in Patent Document 1, the weight of the tire can be reduced by using a part of the belt layer including the cord as a flat circumferential polymer reinforcing element as a resin annular body. However, the tire disclosed in Patent Document 1 still has room for improvement from the viewpoint of durability of the resin annular body.

An object of the present invention is to provide a pneumatic tire in which the durability of the resin annular body is improved while reducing the weight using the resin annular body.

The pneumatic tire according to the first aspect of the present invention is coated with a resin annular body having a reduced diameter portion whose outer diameter decreases toward the outer end in the tire width direction at both ends in the tire width direction, and a coating resin. The resin-coated cord is formed of a resin-coated cord, and the resin-coated cord extends in the tire radial direction of the resin annular body across the reduced diameter portions at both ends in the tire width direction of the resin annular body. A resin-coated belt formed in a spirally wound state with respect to the outer surface, and the resin-coated belt is joined to the resin annular body. The maximum thickness at both ends in the tire width direction is thicker than the maximum thickness at the center in the tire width direction of the resin annular body.

According to the present invention, it is possible to provide a pneumatic tire in which the durability of the resin annular body is improved while reducing the weight using the resin annular body.

It is sectional drawing in the cross section parallel to a tire width direction of the tire as one Embodiment of this invention. It is an expanded sectional view which expands and shows the center part of a tire width direction among the resin annular bodies shown in FIG. It is a figure which shows the modification of the resin annular body shown in FIG. It is a figure which shows the modification of the resin annular body shown in FIG. It is a figure which shows the modification of the resin annular body shown in FIG.

Hereinafter, embodiments of a pneumatic tire according to the present invention will be described with reference to FIGS. 1 to 5. In each figure, the same code | symbol is attached | subjected to the common member and site | part.

Hereinafter, unless otherwise specified, the dimensions, length relationships, positional relationships, etc. of each element are measured in a standard state where a pneumatic tire is mounted on the applicable rim, the specified internal pressure is filled, and no load is applied. And

Here, “applicable rim” is an industrial standard that is effective in the area where pneumatic tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) JATMA YEAR BOOK, and in Europe, ETRTO (The European) STANDARDS MANUAL of TIRE and RIM Technical Organization, STANDARDS of ETRATO STANDARDS in the applicable size described in YEAR BOOK, etc. of TRA (The Tire and Rim Association, Inc.) in the United States or in the future Refers to Measuring Rim, and Design Rim on TRA's YEAR BOOK (i.e., "Applied Rim" above refers to future sizes in addition to the current size) Examples of “sizes to be described in the future” include the sizes described as “FUTURE DEVELOPMENTS” in the ETRTO 2013 edition). In the case of a size not described in the industry standard, it means a rim having a width corresponding to the bead width of the pneumatic tire.
The “specified internal pressure” refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity of a single wheel in the applicable size / ply rating described in the above JATMA YEAR BOOK, etc. In the case of no size, the air pressure (maximum air pressure) corresponding to the maximum load capacity defined for each vehicle on which the tire is mounted is assumed. In addition, the “maximum load load” described later is defined for each vehicle on which a tire is mounted in the case of a tire maximum load capacity of the standard of JATMA or the like in the tire of an applicable size, or in the case of a size not described in the industrial standard. It means the load corresponding to the maximum load capacity.

FIG. 1 is a view showing a pneumatic tire 1 (hereinafter simply referred to as “tire 1”) as the present embodiment. FIG. 1 is a cross-sectional view of the tire 1 in a cross section parallel to the tire width direction A. FIG. Hereinafter, this cross section is referred to as “tire width direction cross section”. In addition, although the tire 1 of this embodiment is a structure symmetrical with respect to the tire equatorial plane CL, a structure asymmetrical with respect to the tire equatorial plane CL may be sufficient.

As shown in FIG. 1, the tire 1 includes a tread portion 1a, a pair of sidewall portions 1b extending inward in the tire radial direction B from both ends in the tire width direction A of the tread portion 1a, and each sidewall portion 1b. And a pair of bead portions 1c provided at the inner end in the tire radial direction B. The tire 1 of this embodiment is a tubeless type radial tire for a passenger car. Here, the “tread portion 1a” means a portion sandwiched between the tread ends TE on both sides in the tire width direction A. Further, the “bead portion 1 c” means a portion where a bead member 3 described later is located in the tire radial direction B. The “sidewall portion 1b” means a portion between the tread portion 1a and the bead portion 1c. The “tread end TE” means a position on the outermost side in the tire width direction of the ground contact surface in a state where the tire is mounted on the above-described application rim, filled with the above-mentioned specified internal pressure, and a maximum load is applied. .

The tire 1 includes a bead member 3, a carcass 4, a resin annular body 5, a resin-coated belt 6, a tread rubber 7, a side rubber 8, and an inner liner 9.

[Bead member 3]
The bead member 3 is embedded in the bead portion 1c. The bead member 3 includes a bead core 3a and a rubber bead filler 3b positioned on the outer side in the tire radial direction B with respect to the bead core 3a. The bead core 3a includes a plurality of bead wires that are covered with rubber. The bead wire is formed of a steel cord. The steel cord can be made of, for example, steel monofilament or stranded wire.

[Carcass 4]
The carcass 4 extends between the pair of bead portions 1c, more specifically between the bead cores 3a of the pair of bead members 3, and extends in a toroidal shape. The carcass 4 has at least a radial structure.

Further, the carcass 4 includes one or more carcass plies 4a in which carcass cords are arranged at an angle of, for example, 75 ° to 90 ° with respect to the tire circumferential direction C (see FIG. 1 and the like). Has been. The carcass ply 4a includes a ply body portion positioned between the pair of bead cores 3a, and a ply folding portion that is folded from the inside to the outside in the tire width direction A around the bead core 3a at both ends of the ply body portion. ing. A bead filler 3b extending from the bead core 3a to the outer side in the tire radial direction B is disposed between the ply main body portion and the ply folded portion. As the carcass cord constituting the carcass ply 4a, a polyester cord is adopted in this embodiment, but other than this, an organic fiber cord such as nylon, rayon, aramid, or a metal cord such as steel is adopted as necessary. Also good. Also, the number of carcass plies 4a may be two or more.

[Resin ring 5]
The resin annular body 5 is disposed in the tread portion 1a. Further, the resin annular body 5 includes reduced

diameter portions

13 and 14 whose outer diameters are reduced toward the outer ends in the tire width direction A at both ends in the tire width direction A. Specifically, the outer surface in the tire radial direction B of the resin annular body 5 of the present embodiment has a barrel shape, and not only the end portion in the tire width direction A but also both sides in the tire width direction A sandwiching the tire equatorial plane CL. The diameter-reducing

portions

13 and 14 are configured. However, a resin annular body in which the reduced

diameter portions

13 and 14 are provided only at the end portion in the tire width direction A may be used. Further, the reduced

diameter portions

13 and 14 at the ends of the resin annular body 5 in the tire width direction A extend to the outside in the tire width direction A from the tread ends TE.

The end of the resin annular body in the tire width direction A means a portion in the tire width direction A that is separated from the tire equator plane CL by a distance of 1/4 of the tire ground contact width W. On the other hand, the central portion of the resin annular body in the tire width direction A means a portion in the tire width direction A that is within a distance of 1/4 of the tire ground contact width W from the tire equatorial plane CL. Here, the “tire contact width” is a distance in the tire width direction between the tread ends TE in a state where the tire is mounted on the above-described applied rim, filled with the specified internal pressure, and in a no-load state.

Compared with the case where the resin annular body 5 includes the reduced

diameter portions

13 and 14 and the reduced

diameter portions

13 and 14 are not provided and the inner diameter and the outer diameter are uniform, the position in the vicinity of the tread end TE. Thus, it is possible to suppress the ground pressure from locally increasing and to suppress uneven wear on the outer surface of the tread. Moreover, it can suppress that a distortion concentrates on the edge part of the tire width direction A of the resin annular body 5. FIG. Thereby, it can suppress that damage, such as a crack, arises in the edge part of the tire width direction A of the resin annular body 5. FIG. That is, the durability of the resin annular body 5 can be further improved.

As the resin constituting the resin annular body 5, for example, a thermoplastic elastomer or a thermoplastic resin can be used, and a resin that is cross-linked by heat or an electron beam or a resin that is cured by thermal rearrangement can also be used. The resin constituting the resin annular body 5 does not include rubber (an organic polymer substance exhibiting rubber elasticity at room temperature).

As thermoplastic elastomers, polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), polyester-based thermoplastic elastomer (TPC) And dynamic crosslinkable thermoplastic elastomer (TPV). Examples of the thermoplastic resin include polyurethane resin, polyolefin resin, vinyl chloride resin, polyamide resin and the like. Further, as the thermoplastic resin, for example, the deflection temperature under load (at the time of 0.45 MPa load) specified in ISO75-2 or ASTM D648 is 78 ° C or more, and the tensile yield strength specified in JIS K7113 is used. A material having a tensile breaking elongation of 50% or more as defined in JIS K7113 and a Vicat softening temperature (Method A) as defined in JIS K7206 of 130 ° C. or more can be used. Particularly preferred are TPA, TPC, TPV, polyamide resin, polyester resin and blends thereof.

The elastic modulus of the resin annular body 5 can be set in the range of 100 MPa to 1000 MPa, more preferably in the range of 200 MPa to 700 MPa. The elastic modulus of the resin annular body 5 means a tensile elastic modulus. The tensile elastic modulus is measured according to JIS K7113: 1995. Specifically, using a Shimadzu Autograph AGS-J (5KN) manufactured by Shimadzu Corporation, the tensile modulus is set to 100 mm / min and the tensile elastic modulus is measured. When measuring the tensile elastic modulus of the resin annular body, the measurement data may be adjusted by punching out from the resin annular body.For example, a measurement sample of the same material as the resin annular body is separately prepared and the elastic modulus is measured. May be.

The resin annular body 5 of the present embodiment extends in the tire width direction A to the outside of the resin-coated belt 6 described later. In addition, the resin annular body 5 of the present embodiment is located inside the tire radial direction B of the resin-coated belt 6. Unlike the resin-coated belt 6, the resin annular body 5 does not include a cord. That is, no cord is arranged in the resin annular body 5.

Here, the maximum thickness T1 of both ends of the resin annular body 5 in the tire width direction A is thicker than the maximum thickness T2 of the central part of the resin annular body 5 in the tire width direction A. In the present embodiment, as shown in FIG. 1, as an example, a resin annular body 5 whose thickness gradually increases from the center position in the tire width direction A intersecting the tire equatorial plane CL toward the outside in the tire width direction A is shown. ing. The maximum thickness T1 at both ends in the tire width direction A of the resin annular body 5 of the present embodiment is the thickness at the position of the outer end in the tire width direction A. Further, the maximum thickness T2 of the central portion in the tire width direction A of the resin annular body 5 of the present embodiment is a thickness at a position adjacent to the end portion in the tire width direction A.

Thus, by making the maximum thickness T1 of both ends of the resin annular body 5 in the tire width direction A thicker than the maximum thickness T2 of the central portion of the resin annular body 5 in the tire width direction A, the resin annular body 5 While maintaining the weight reduction of the tire 1 without increasing the thickness of the center portion in the tire width direction A, the thickness of the end portion in the tire width direction A of the resin annular body 5 is increased, so that the tire of the resin annular body 5 is obtained. It can suppress that the

diameter reduction parts

13 and 14 of the edge part of the width direction A are cracked by a ground pressure. That is, the durability of the resin annular body 5 can be improved while realizing the weight reduction of the tire 1 using the resin annular body 5.

Further, the maximum thickness T1 of the end portion in the tire width direction A of the resin annular body 5 is set in the range of 0.1 mm to 3 mm, more preferably in the range of 0.3 mm to 2 mm. Further, the maximum thickness T2 of the central portion in the tire width direction A of the resin annular body 5 is set in the range of 0.1 mm to 2.5 mm, more preferably in the range of 0.2 mm to 1.5 mm.

[Resin-coated belt 6]
The resin-coated belt 6 is disposed on the outer side in the tire radial direction B of the resin annular body 5 in the tread portion 1a. The resin-coated belt 6 includes a cord 10b that is covered with a coating resin 10a. Specifically, the resin-coated belt 6 of the present embodiment has one or more layers (1 in the present embodiment) arranged on the outer side in the tire radial direction B with respect to the crown portion of the carcass 4 and the resin annular body 5. Layer) belt layer. More specifically, as shown in FIG. 1, the resin-coated belt 6 of the present embodiment is constituted by a circumferential belt 6a composed of only one circumferential belt layer.

In the circumferential belt 6a as the resin-coated belt 6 of the present embodiment, a steel cord as a metal belt cord is 10 ° or less, preferably 5 ° or less, more preferably 5 ° or less with respect to the tire circumferential direction C (see FIG. 1 and the like). Is a spiral belt formed in a state of being spirally wound around the tire center axis at an angle of 2 ° or less. More specifically, the circumferential belt 6a as the resin-coated belt 6 of the present embodiment is formed by a resin-coated cord 10 made of a cord 10b such as a steel cord coated with a coating resin 10a. That is, the circumferential belt 6a as the resin-coated belt 6 extends between the reduced

diameter portions

13 and 14 at both ends in the tire width direction A of the resin annular body 5 on the outer surface of the resin annular body 5 in the tire radial direction B. On the other hand, it is comprised by the resin-coated code | cord | chord 10 of the state wound helically.

The resin-coated cord 10 is wound around the outer surface of the resin annular body 5 in the tire radial direction B while being joined to the outer surface of the resin annular body 5 in the tire radial direction B. In this embodiment, the resin-coated cord 10 and the resin annular body 5 are joined by welding the coating resin 10 a of the resin-coated cord 10 and the resin annular body 5. However, the coating resin 10a of the resin coating cord 10 and the resin annular body 5 are not limited to welding, and may be joined by bonding with an adhesive or the like.

Further, the resin-coated cord 10 of the present embodiment is joined at adjacent portions in the tire width direction A. In this embodiment, the parts adjacent to the tire width direction A of the resin-coated cord 10 are joined together by welding the coating resin 10a. However, the portions adjacent to the tire width direction A of the resin-coated cord 10 are not limited to welding, and may be joined by bonding with an adhesive or the like.

The portions adjacent to each other in the tire width direction A of the resin-coated cord 10 spirally wound around the resin annular body 5 are at least the positions of the reduced

diameter portions

13 and 14 of the resin annular body 5 in the tire width direction A. It is preferable to adopt a configuration in which the two are joined. As described above, the diameter-reduced

portions

13 and 14 of the annular resin body 5 are easily strained due to the contact pressure and easily damaged. Therefore, the ground pressure can be distributed over a wider range of the resin annular body 5 through the resin-coated belt 6 by joining the portions of the resin-coated cord 10 adjacent to each other in the tire width direction A. As a result, it is possible to suppress strain from concentrating on the reduced

diameter portions

13 and 14 of the resin annular body 5, and the durability of the resin annular body 5 can be further improved.

In the present embodiment, the portions adjacent to each other in the tire width direction A of the resin-coated cord 10 spirally wound around the resin annular body 5 are the reduced diameter portion 13 of the resin annular body 5 in the tire width direction A and Not only the position 14 but also the entire region in the tire width direction A is joined.

The resin-coated belt 6 of the present embodiment has a substantially constant thickness regardless of the position in the tire width direction A. The thickness of the resin-coated belt 6 of the present embodiment can be set, for example, in the range of 1.5 mm to 7 mm, more preferably in the range of 2 mm to 5 mm. The elastic modulus of the coating resin 10a of the resin-coated belt 6 can be set in the range of 100 MPa to 1000 MPa, more preferably in the range of 200 MPa to 700 MPa. The tensile elastic modulus is measured according to JIS K7113: 1995. Specifically, using a Shimadzu Autograph AGS-J (5KN) manufactured by Shimadzu Corporation, the tensile modulus is set to 100 mm / min and the tensile elastic modulus is measured. When measuring the tensile elastic modulus of the coating resin, the measurement data may be adjusted by punching out from the coating resin if possible.For example, a measurement sample of the same material as the coating resin is prepared separately and the elastic modulus is measured. May be.

As shown in FIG. 1, the resin-coated cord 10 of the present embodiment includes two steel cords, but may be a resin-coated cord including only one steel cord, or a resin including three or more steel cords. It is good also as a covering cord.

Any known material can be used for the cord 10b, for example, the above-described steel cord can be used. The steel cord can be made of, for example, steel monofilament or stranded wire. Moreover, the cord 10b can also use organic fiber, carbon fiber, or those strands.

Further, as the coating resin 10a, for example, a thermoplastic elastomer or a thermoplastic resin can be used, and a resin that is cross-linked by heat or an electron beam, or a resin that is cured by thermal dislocation can also be used. As thermoplastic elastomers, polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), polyester-based thermoplastic elastomer (TPC) And dynamic crosslinkable thermoplastic elastomer (TPV). Examples of the thermoplastic resin include polyurethane resin, polyolefin resin, vinyl chloride resin, polyamide resin and the like. Further, as the thermoplastic resin, for example, the deflection temperature under load (at the time of 0.45 MPa load) specified in ISO75-2 or ASTM D648 is 78 ° C or more, and the tensile yield strength specified in JIS K7113 is used. A material having a tensile breaking elongation of 50% or more as defined in JIS K7113 and a Vicat softening temperature (Method A) as defined in JIS K7206 of 130 ° C. or more can be used. The tensile elastic modulus (specified in JIS K7113: 1995) of the coating resin 10a that covers the cord 10b is preferably 50 MPa or more. The tensile modulus of the coating resin 10a that covers the cord 10b is preferably 1000 MPa or less. The coating resin 10a here does not include rubber (an organic polymer substance exhibiting rubber elasticity at room temperature).

[Tread rubber 7 and side rubber 8]
The tread rubber 7 constitutes an outer surface of the tread portion 1a in the tire radial direction B (hereinafter referred to as “tread outer surface”), and the tread outer surface of the present embodiment has a tire circumferential direction C (see FIG. 1), a tread pattern including a circumferential groove 7a extending in the tire width direction A and a width direction groove (not shown) extending in the tire width direction A is formed. The side rubber 8 constitutes the outer surface of the sidewall portion 1b in the tire width direction A, and is formed integrally with the tread rubber 7 described above.

[Inner liner 9]
The inner liner 9 is laminated on the inner surface of the carcass 4 and is formed of butyl rubber having low air permeability in the present embodiment. The butyl rubber means butyl rubber and halogenated butyl rubber which is a derivative thereof.

Hereinafter, further details of the tire 1 of the present embodiment will be described.

In a cross-sectional view in the tire width direction (see FIG. 1), the minimum thickness T3 of the resin annular body 5 of the present embodiment is preferably 80% or more of the maximum thickness T1 of the resin annular body 5, and preferably 90% or more. Is more preferable. The minimum thickness T3 of the present embodiment means the thickness of the resin annular body 5 at the center position in the tire width direction A that intersects the tire equatorial plane CL. By adopting such a configuration, the end portion in the tire width direction A of the resin annular body 5 can be thickened to reduce deformation distortion, and the center portion and the end portion in the tire width direction A of the resin annular body 5 can be reduced. It is easy to adjust the distribution in the tire width direction A of the contact pressure applied to the tread portion 1a. Thereby, it can suppress that partial wear arises in a part of tire width direction A of a tread outer surface, and can improve durability of a tire.

The thickness of the resin annular body 5 is preferably in the range of 0.1 mm to 3.0 mm. Specifically, the minimum thickness T3 of the resin annular body 5 is preferably 0.1 mm or more, and the maximum thickness T1 of the resin annular body 5 is preferably 3.0 mm or less. By setting the minimum thickness T3 to 0.1 mm or more, the strength of the resin annular body 5 can be secured, and the occurrence of damage such as cracks can be suppressed. As a result, the durability of the resin annular body 5 can be further improved. By setting the maximum thickness T1 to 3.0 mm or less, the effect of reducing the tire weight by using the resin annular body 5 can be enhanced.

FIG. 2 is an enlarged cross-sectional view showing an enlarged central portion in the tire width direction A of the resin annular body 5 shown in FIG. As shown in FIG. 2, the resin annular body 5 of the present embodiment is formed by joining a resin-made first annular portion 5 a and a resin-made second annular portion 5 b in the vicinity of the tire equatorial plane CL. Has been. Specifically, as shown in FIG. 2, an annular end surface 11 on one side in the tire width direction A of the first annular portion 5a and an annular end surface 12 on the other side in the tire width direction A of the second annular portion 5b are provided. Are joined by welding. As described above, the resin annular body 5 of the present embodiment has a seam formed by joining at a predetermined position in the tire width direction A. However, the configuration is not limited to such a seam.

FIG. 3 is a view showing a resin annular body 305 as a modified example of the resin annular body 5 of the present embodiment. The resin annular body 305 shown in FIG. 3 is an integrally molded product in which no seam is formed in the tire width direction A. By adopting such a configuration, it is possible to eliminate a joint where breakage or the like is likely to occur, and thus it is possible to realize a more durable resin annular body 305. In addition, the manufacturing method of such a resin annular body 305 can utilize, for example, injection molding or blow molding, but the manufacturing method is not particularly limited.

The pneumatic tire according to the present invention is not limited to the specific configurations shown in the above-described embodiments and modifications, and various modifications and changes can be made without departing from the scope of the claims.

In FIG. 1, the resin annular body 5 whose thickness gradually increases from the center position in the tire width direction A intersecting the tire equatorial plane CL toward the outside in the tire width direction A is shown. The configuration is not particularly limited as long as the maximum thickness T1 of both end portions of A is thicker than the maximum thickness T2 of the central portion in the tire width direction A of the resin annular body.

FIG. 4 is a view showing a resin annular body 105 as a modified example of the resin annular body 5. Also in the resin annular body 105 shown in FIG. 4, the maximum thickness T <b> 1 at both ends in the tire width direction A is thicker than the maximum thickness T <b> 2 at the center in the tire width direction A of the resin annular body 105. In the resin annular body 105 shown in FIG. 4, the central portion in the tire width direction A is formed with a substantially constant thickness. Further, in the resin annular body 105 shown in FIG. 4, both end portions in the tire width direction A are formed with a substantially constant thickness different from the thickness of the central portion. Therefore, the maximum thickness T1 at both ends in the tire width direction A of the resin annular body 105 shown in FIG. 4 is the thickness at an arbitrary position at both ends in the tire width direction A. Further, the maximum thickness T2 of the central portion in the tire width direction A of the resin annular body 105 shown in FIG. 4 is the thickness at an arbitrary position of the central portion in the tire width direction A. A stepped surface extending toward the inner surface of the tire is formed on the inner surface of the resin annular body 105 in the tire radial direction B. The inner surface of the end portion in the tire width direction A of the resin annular body 105 and the inner surface of the center portion in the tire width direction A of the resin annular body 105 are connected via the above-described step surface.

FIG. 5 is a view showing a resin annular body 205 as another modified example of the resin annular body 5. Also in the resin annular body 205 shown in FIG. 5, the maximum thickness T <b> 1 at both ends in the tire width direction A is thicker than the maximum thickness T <b> 2 at the center in the tire width direction A of the resin annular body 205. In the resin annular body 205 shown in FIG. 5, the central portion in the tire width direction A is formed with a substantially constant thickness, but both end portions in the tire width direction A are thicker toward the outer ends in the tire width direction A. Is configured to increase gradually. Therefore, the maximum thickness T1 of both end portions in the tire width direction A of the resin annular body 205 shown in FIG. 5 is the thickness at the position of the outer end in the tire width direction A. Further, the maximum thickness T2 of the central portion in the tire width direction A of the resin annular body 205 shown in FIG. 5 is the thickness at an arbitrary position of the central portion in the tire width direction A.

However, like the resin annular body 5 shown in FIG. 1 and the resin annular body 205 shown in FIG. 5, it is preferable that a step surface, a corner, or the like is not formed on the inner surface and the outer surface in the tire radial direction B. . If it does in this way, resin

annular bodies

5 and 205 will be easy to stick to a member which adjoins in tire diameter direction B, and it can control that failure, such as separation, occurs between adjacent members.

The resin

annular bodies

5, 105, 205 and 305 shown in FIGS. 1 and 3 to 5 have a barrel-shaped outer shape, but there are reduced diameter portions only at both ends in the tire width direction A. The central portion in the tire width direction A may be a resin annular body configured by a cylindrical portion having a uniform inner diameter and outer diameter.

The present invention relates to a pneumatic tire.

1: pneumatic tire, 1a: tread portion, 1b: sidewall portion, 1c: bead portion, 3: bead member, 3a: bead core, 3b: bead filler, 4: carcass, 4a: carcass ply, 5, 105, 205, 305: resin annular body, 5a: first annular portion, 5b: second annular portion, 6: resin coated belt, 6a: circumferential belt, 7: tread rubber, 7a: circumferential groove, 8: side rubber, 9: inner Liner, 10: resin coated cord, 10a: coated resin, 10b: cord, 11: annular end surface of first annular portion, 12: annular end surface of second annular portion, 13, 14: reduced diameter portion, A: tire width direction , B: tire radial direction, C: tire circumferential direction, T1: maximum thickness of the end of the resin annular body in the tire width direction, T2: resin annular tie The maximum thickness of the central portion in the width direction, T3: the minimum thickness of the central portion in the tire width direction of the resin annular body, W: tire contact width, CL: tire equatorial plane, TE: tread edge

Claims

At both ends in the tire width direction, a resin annular body provided with a reduced diameter portion whose outer diameter decreases toward the outer end in the tire width direction,
The resin-coated cord is composed of a cord coated with a coating resin, and the resin-coated cord extends between the reduced diameter portions at both ends in the tire width direction of the resin annular body. With respect to the outer surface in the tire radial direction, a resin-coated belt formed in a spirally wound state is provided in the tread portion,
The resin-coated belt is bonded to the resin annular body,
The maximum thickness of the both ends of the said resin annular body of the tire width direction is a pneumatic tire thicker than the maximum thickness of the center part of the said resin annular body of the tire width direction.
The pneumatic tire according to claim 1, wherein the resin-coated cords are joined at portions adjacent to each other in the tire width direction.
3. The pneumatic tire according to claim 1, wherein a minimum thickness of the resin annular body is 80% or more of a maximum thickness of the resin annular body in a cross-sectional view parallel to the tire width direction.
The pneumatic tire according to any one of claims 1 to 3, wherein the resin annular body is an integrally molded product in which a seam is not formed in a tire width direction.
The pneumatic tire according to any one of claims 1 to 4, wherein a thickness of the resin annular body is in a range of 0.1 mm to 3.0 mm.