WO2019230773A1

WO2019230773A1 - Pneumatic tire

Info

Publication number: WO2019230773A1
Application number: PCT/JP2019/021239
Authority: WO
Inventors: 圭一長谷川
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: JP2019209755A

Abstract

A pneumatic tire of the present invention is provided with: a belt comprising a cord coated with a coating material and wound spirally in a tire circumferential direction; and a widthwise reinforcing member. The pneumatic tire further includes one or more circumferential main grooves extending continuously in the tire circumferential direction. The widthwise reinforcing member is disposed at least across a region between tire widthwise ends of the one or more circumferential main grooves.

Description

Pneumatic tire

The present invention relates to a pneumatic tire.

Conventionally, in a pneumatic tire, a belt is usually disposed outside the carcass in the tire radial direction in order to improve tire performance (for example, Patent Document 1).

It has also been proposed that the belt is formed by spirally winding a resin-coated cord or a rubber-coated cord with a cord coated with a coating material such as resin or rubber in the tire circumferential direction (so-called spiral belt). Yes.

Japanese Patent Laid-Open No. 10-035220

However, a belt formed by spirally winding a resin-coated cord or a rubber-coated cord in the tire circumferential direction has a problem that it is weak against input due to protrusions or the like because its binding force in the tire width direction is slightly low. .

Therefore, an object of the present invention is to provide a pneumatic tire having excellent protrusion penetration resistance.

The gist configuration of the present invention is as follows.
The pneumatic tire of the present invention comprises a belt in which a cord covered with a coating material is spirally wound in the tire circumferential direction, and a width direction reinforcing member,
And further including one or more circumferential main grooves extending continuously in the tire circumferential direction;
The width direction reinforcing member is arranged over at least a region between end portions in the tire width direction of the one or more circumferential main grooves.

Here, the “circumferential main groove” refers to a groove having a groove width (opening width) of 2 mm or more. Here, the “groove width” and other dimensions in the present specification are measured in a state in which the tire is mounted on the applicable rim, filled with the specified internal pressure, and in a no-load state. The “circumferential main groove” may extend linearly, or may extend in a curved shape or zigzag shape, and in the case of linear extension, it extends at an inclination angle of 10 ° or less with respect to the tire circumferential direction. Preferably it is.
However, “tire contact width” means that the outermost position in the tire width direction of the contact surface in the state where the tire is mounted on the applicable rim, the specified internal pressure is filled, and the maximum load is applied is the ground end, and the tire is applied to the applicable rim. It is set as the distance in the tire width direction between the ground contact ends in a state in which it is mounted and filled with the specified internal pressure and is in a no-load state.

In this specification, “applicable rim” is an industrial standard effective in the region where tires are produced and used. In Japan, JATMA (Japan Automobile Tire Association) JATMA YEAR BOOK, and in Europe, ETRTO (The European) Tire and Rim Technical Organization's STANDARDDS MANUAL, in the United States TRA (The Tire and Rim Association, Inc.) YEAR BOOK, etc. Standard rim (ETRTOSTANDAND in the applicable size to be described in the future) Refers to Measuring Rim, TRA's YEAR BOOK, Design Rim) (ie, “Rim” above) In addition to the current size, it includes the size that can be included in the above industrial standards in the future.As an example of “future size to be described”, it is described as “FUTURE DEVELOPMENTS” in ETRTO STANDARDDS MANUAL 2013 edition. However, in the case of a size not described in the industry standard, it means a rim having a width corresponding to the tire bead width. The “specified internal pressure” refers to an air pressure (maximum air pressure) corresponding to the tire maximum load capacity of the standard such as JATMA in a tire of an applicable size. In the case of a size not described in the industry standard, the “specified internal pressure” refers to an air pressure (maximum air pressure) corresponding to a maximum load capacity specified for each vehicle on which a tire is mounted. “Maximum load load” is the tire maximum load capacity of the standard such as JATMA for the tire of the applicable size, or, in the case of a size not described in the industry standard, the maximum load capacity defined for each vehicle on which the tire is mounted. Means the load corresponding to.

According to the present invention, the present invention can provide a pneumatic tire excellent in protrusion penetration resistance.

1 is a schematic cross-sectional view in the tire width direction showing a pneumatic tire according to an embodiment of the present invention. It is a schematic sectional drawing which shows the belt, the resin reinforcement layer, and the width direction reinforcement member in embodiment shown in FIG. It is a tire width direction schematic sectional drawing which shows the pneumatic tire concerning other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view in the tire width direction showing a pneumatic tire according to an embodiment of the present invention. As shown in FIG. 1, the pneumatic tire 1 of the present embodiment (hereinafter also simply referred to as a tire) includes a carcass 3 straddling a bead core 2 a embedded in a pair of bead portions 2 in a toroidal shape. The tire 1 includes a belt 4 and a tread 5 in this order on the outer side in the tire radial direction of the crown portion of the carcass 3. As shown in FIG. 1, the tire 1 of the present embodiment has the same configuration between the half portions in the tire width direction with the tire equatorial plane CL as a boundary, but may be asymmetrical. .

The tire 1 of the present embodiment has a bead core 2a in which steel cords are bundled. The material and shape of the bead core are not particularly limited, or may have a structure without the bead core 2a. Moreover, in this embodiment, although the carcass 3 is comprised by the one carcass ply consisting of organic fiber, the material and the number of carcass plies are not particularly limited.

In this embodiment, the belt 4 is a spiral belt in a state in which a resin-coated cord in which the cord 4b is coated with the coating resin 4a is spirally wound around the tire axis. In the present invention, the belt 4 is preferably a single layer. It is because it is preferable from a viewpoint of weight reduction. The width of the belt 4 in the tire width direction can be, for example, 90 to 120% of the tire ground contact width. The thickness (maximum thickness) of the belt 4 is not particularly limited, but may be 2 to 6 mm, for example. As the cord 4b, any known material can be used, for example, a steel cord can be used. The steel cord can be made of, for example, steel monofilament or stranded wire. The cord 4b can also use organic fiber, carbon fiber, or the like. Further, as the coating resin 4a, 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 (when 0.45 MPa is loaded) specified in ISO 75-2 or ASTM D648 is 78 ° C or more, and the tensile yield strength specified in JIS K7113 is used. 10 MPa or more, and the tensile elongation at break (JIS K7113) specified in JIS K7113 is 50% or more and the Vicat softening temperature (Method A) specified in JIS K7206 is 130 ° C or more. Can do. The tensile elastic modulus (specified in JIS K7113: 1995) of the coating resin 4a that covers the cord 4b is preferably 50 MPa or more. This is because the belt rigidity can be increased. The tensile modulus of the coating resin 4a that covers the cord 4b is preferably 1000 MPa or less. This is because the ride comfort can be maintained well. The coating resin 4a here does not include rubber (an organic polymer substance exhibiting rubber elasticity at room temperature). The resin-coated cord can be formed, for example, by coating a molten coating resin 4a on the outer peripheral side of the cord 4b and solidifying by cooling.

FIG. 2 is a schematic sectional view showing the belt 4, the resin reinforcing layer 6, and the width direction reinforcing member 7 in the embodiment shown in FIG. As shown in FIGS. 1 and 2, the tire 1 of the present embodiment includes a resin reinforcing layer 6 on the inner side in the tire radial direction of the belt 4. The resin reinforcing layer 6 is a layer made of a plate-like resin. In the illustrated example, the width of the resin reinforcing layer 6 in the tire width direction is larger than the width of the belt 4 in the tire width direction, and can be, for example, 100 to 130% of the tire ground contact width. The thickness (maximum thickness) of the resin reinforcing layer 6 is not particularly limited, but may be, for example, 0.1 to 3 mm. As the resin of the resin reinforcing layer 6, a resin of the same material as the coating resin 4 a of the belt 4 can be used, but a different resin can also be used. The tensile modulus of elasticity of the resin of the resin reinforcing layer 6 (specified in JIS K7113: 1995) is preferably 50 MPa or more. Moreover, it is preferable that the tensile elasticity modulus of resin of the resin reinforcement layer 6 shall be 1000 Mpa or less. By having such a resin reinforcement layer 6, it is possible to reinforce and enhance the belt rigidity while maintaining good riding comfort and the like. FIG. 3 is a schematic cross-sectional view in the tire width direction showing a pneumatic tire according to another embodiment of the present invention. As shown in FIG. 3, in the present invention, a configuration without the resin reinforcing layer 6 may be employed. Further, as shown in FIG. 3, in the present invention, a width direction reinforcing member 7 can be disposed on the inner side in the tire radial direction of the carcass 3.

As shown in FIG. 1, the tire 1 of the present embodiment further includes a width direction reinforcing member 7 on the inner side of the belt 4 in the tire radial direction (in this example, on the inner side of the resin reinforcing layer 6 in the tire radial direction). . In the illustrated example, the width of the width direction reinforcing member 7 in the tire width direction is smaller than the width of the belt 4 in the tire width direction, and may be, for example, 80 to 110% of the tire ground contact width. The thickness (maximum thickness) of the width direction reinforcing member 7 is not particularly limited, but may be 0.5 to 1.5 mm, for example.

In the present embodiment, the width-direction reinforcing member 7 is a member formed by rubber-coating (one or a plurality of) steel cords or organic fiber cords extending obliquely with respect to the tire circumferential direction. Thereby, the rigidity in the tire width direction can be increased. From the viewpoint of ensuring rigidity in the tire width direction, the steel cord or the organic fiber cord is preferably inclined at an angle of 45 to 90 ° with respect to the tire circumferential direction. As the rubber, any known material may be used. For example, a rubber often used for tire rubber may be used. As the steel cord, one made of monofilament or one obtained by twisting a plurality of monofilaments can be used. For example, nylon or the like can be used as the organic fiber, and a single fiber or a plurality of single fibers twisted together can be used.

Alternatively, as another embodiment, the width direction reinforcing member 7 may be a member made of resin. In this case, since the resin has a higher rigidity than the weight, it is preferable to reduce the weight by adopting a configuration without the steel cord or the organic fiber cord. However, in order to further increase the rigidity in the width direction, the steel cord or the organic fiber is preferable. The cord may be covered with a resin. As the resin of the width direction reinforcing member 7, a resin of the same material as the coating resin 4 a of the belt 4 can be used, but a different resin can also be used. The tensile modulus of elasticity of the resin of the width direction reinforcing member 7 (specified in JIS K7113: 1995) is preferably 50 MPa or more. This is because the belt rigidity can be reinforced and increased. Moreover, it is preferable that the tensile elasticity modulus of resin of the width direction reinforcement member 7 shall be 1000 Mpa or less. It is because riding comfort etc. can be maintained favorable.

As shown in FIG. 1, the tire 1 of the present embodiment has one or more tires (in the illustrated example, the tire equator) that are inclined at an angle of 10 ° or less and continuously extend linearly. Further, there are four circumferential main grooves 8 in total in the tire width direction half with the surface CL as a boundary. The number and arrangement of the circumferential main grooves 8 may be arbitrary (if one or more are provided).

And in the tire 1 of this embodiment, the width direction reinforcement member 7 is arrange | positioned over the area | region between the tire width direction edge parts of the 1 or more circumferential direction main groove 8 at least. In the illustrated example, the width direction reinforcing member 7 extends continuously in the tire width direction. That is, the width direction reinforcing member 7 is disposed at a position in the tire width direction corresponding to one or more circumferential main grooves 8, and the width of the width direction reinforcing member 7 in the tire width direction is the circumferential direction main groove 8. It is larger than the width in the tire width direction between the ends in the tire width direction. The width direction reinforcing member 7 is preferably provided in a tire width direction region including at least the tire equatorial plane CL. In addition, when two or more circumferential main grooves 8 are provided, the width direction reinforcing member 7 may be provided at least in the entire region in the tire width direction region between the two circumferential main grooves closest to the tire equatorial plane CL. preferable.
Hereinafter, the effect of the pneumatic tire of this embodiment is explained.

In the pneumatic tire of the present embodiment, first, in this example, since the resin reinforcing layer 6 is disposed on the inner side in the tire radial direction of the belt 4, the rigidity of the belt 4 is sufficiently reinforced to enhance the steering stability. Etc. can be improved.
Furthermore, since the pneumatic tire of the present embodiment has the width direction reinforcing member 7 in the tire width direction region, the rigidity in the tire width direction is provided at the portion where the circumferential main groove 8 is disposed with low rigidity. By arranging the high member, the width direction reinforcing member 7 bears the tensile force in the tire width direction that is generated when the protrusion is overcome, so that the protrusion penetration resistance can be improved. Since the tensile force in the tire width direction at the time of overcoming the protrusion is generated more strongly on the inner side in the tire radial direction, the width direction reinforcing member 7 is placed on the inner side in the tire radial direction of the belt 4 (in this embodiment, the tire radial direction of the resin reinforcing layer 6 By arranging the inner side), the width direction reinforcing member 7 can bear the tensile force in the tire width direction more effectively.
Furthermore, in the present embodiment, the belt 4 is a resin-coated belt, and since the resin has higher rigidity than the weight in comparison with rubber, it is possible to improve tire performance such as steering stability while reducing the weight. it can.
Moreover, since the width direction reinforcing member 7 is made of steel cord or organic fiber cord covered with rubber, the rigidity in the tire width direction can be higher than the rigidity in the tire circumferential direction depending on the extending direction of the cord. It can be adjusted by the inclination angle of the cord.
As described above, according to the pneumatic tire of the present embodiment, the protrusion penetration resistance can be improved.

In the pneumatic tire of the present invention, as in the above-described embodiment, the coating material is preferably a resin. This is because the resin has higher rigidity than the weight in comparison with the rubber, so that the tire performance such as steering stability can be improved while reducing the weight.

In the pneumatic tire of the present invention, as in the other embodiments described above, the covering material is preferably rubber. This is because the rubber-coated cord is particularly excellent in manufacturability.

In the pneumatic tire of the present invention, as in the above-described embodiment, the width-direction reinforcing member 7 is a member formed by rubber coating a steel cord or an organic fiber cord extending obliquely with respect to the tire circumferential direction. Is preferred. Since the rigidity in the extending direction of the cord can be increased, it can be adjusted by the extending angle of the cord or the like when securing the rigidity of the width direction reinforcing member 7 in the tire width direction. The steel cord or the organic fiber cord preferably extends at an inclination angle of 80 ° to 90 ° with respect to the tire circumferential direction in order to ensure rigidity in the tire width direction.

In the pneumatic tire of the present invention, the width direction reinforcing member is preferably a member made of resin. This is because the rigidity of the resin is higher than the weight, so that the rigidity of the width direction reinforcing member 7 in the tire width direction can be ensured while reducing the weight.

In the pneumatic tire of the present invention, two or more circumferential main grooves 8 are provided, and in the tire width direction region between the two circumferential main grooves 8 adjacent in the tire width direction, the width direction reinforcement is performed. It is preferable to have a region where the member 7 is not disposed. By disposing the width direction reinforcing member 7 discretely only in the region where the rigidity is reduced by the circumferential main groove 8, the protrusion penetration resistance is improved while suppressing an increase in weight by the width direction reinforcing member 7. Because it can.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment at all. For example, in the above embodiment, the width direction reinforcing member 7 is disposed on the inner side in the tire radial direction of the belt 4, but the width direction reinforcing member 7 may be disposed on the outer side in the tire radial direction of the belt 4. Further, for example, in the above embodiment, the width of the resin reinforcing layer 6 in the tire width direction is larger than the width of the belt 4 in the tire width direction, but may be the same or smaller. Further, the width direction reinforcing member 7 may be provided outside the resin reinforcing layer 6 in the tire radial direction as long as it is inside the belt 4 in the tire radial direction. Or it can also be set as the structure which does not provide the resin reinforcement layer 6. FIG. In this embodiment, the width of the width direction reinforcing member 7 in the tire width direction is smaller than the width of the belt 4 and the resin reinforcing layer 6 in the tire width direction, but either or both of the belt 4 and the resin reinforcing layer 6 are used. It may be larger than the width in the tire width direction. This means that, depending on the position of the circumferential main groove 8 in the tire width direction (for example, when the circumferential main groove 8 is arranged on the outer side in the tire width direction), the width direction reinforcing member 7 is moved to the position in the tire width direction. Not only when it becomes such a large width to be arranged over the entire region, but also when the negative rate of the width direction groove of the shoulder portion is large (for example, 30% or more), etc., the shoulder portion with low rigidity In order to reinforce the protrusion and further improve the protrusion penetration resistance, such a large width can be used.

In a run-flat tire of tire size 225 / 40R18, when the width direction reinforcing member 7 having a width of 60 mm in the tire width direction is arranged (FIG. 3) (invention example) and when the width direction reinforcing member 7 is not arranged (comparison) In Example), a plunger test was conducted.
The evaluation results are shown in Table 1.
An index value with the evaluation result of the comparative example as 100 is shown, and a larger value indicates superior plunger durability (protrusion penetration resistance).

As shown in Table 1, it can be seen that the invention example in which the width direction reinforcing member 7 having a width of 60 mm in the tire width direction is arranged has higher plunger durability than the comparative example.

1: pneumatic tire, 2: bead part, 2a: bead core, 3: carcass,
4: resin-coated belt, 4a: coated resin, 4b: cord, 5: tread,
6: resin reinforcing layer, 7: width direction reinforcing member, 8: circumferential main groove,
CL: Tire equator

Claims

A belt in which a cord covered with a coating material is spirally wound in a tire circumferential direction, and a width direction reinforcing member,
And further including one or more circumferential main grooves extending continuously in the tire circumferential direction;
The pneumatic tire according to claim 1, wherein the width direction reinforcing member is disposed at least over a region between end portions in the tire width direction of the one or more circumferential main grooves.
The pneumatic tire according to claim 1, wherein the coating material is a resin.
The pneumatic tire according to claim 1, wherein the coating material is rubber.
The pneumatic tire according to any one of claims 1 to 3, wherein the reinforcing member in the width direction is a member formed by covering a steel cord or an organic fiber cord extending at an inclination with respect to the tire circumferential direction with rubber.
The pneumatic tire according to any one of claims 1 to 3, wherein the width direction reinforcing member is a member made of resin.
Having two or more circumferential main grooves,
The tire width direction region between the two circumferential main grooves adjacent to each other in the tire width direction has a region where the width direction reinforcing member is not disposed. The described pneumatic tire.