WO2019230761A1

WO2019230761A1 - Pneumatic tire

Info

Publication number: WO2019230761A1
Application number: PCT/JP2019/021225
Authority: WO
Inventors: 誓志今
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: JP2019209761A

Abstract

This pneumatic tire is provided with a belt in which a cord coated with a coating material is wound helically in the tire circumferential direction, and a resin member which is disposed outside or inside the belt in the tire radial direction. Fibers oriented in a predetermined direction which is tilted relative to the tire circumferential direction are arranged in the resin member.

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 is also proposed to use a belt in which a resin-coated cord or rubber-coated cord, etc., in which the cord is coated with a coating material such as resin or rubber, is spirally wound in the tire circumferential direction (so-called spiral belt). Has been.

Japanese Patent Laid-Open No. 10-035220

However, a belt in which a resin-coated cord or a rubber-coated cord is spirally wound in the tire circumferential direction has almost no binding force in the tire width direction, and is therefore weak against input by protrusions or the like. was there.

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 includes a belt in which a cord covered with a coating material is spirally wound in the tire circumferential direction, and a resin member disposed on the outer side or the inner side of the belt in the tire radial direction. And fibers oriented in a predetermined direction inclined with respect to the tire circumferential direction are arranged in the resin member.

According to the present invention, it is possible to 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.

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 rubber-coated cord in which a cord 4b is coated with a coating rubber 4a is spirally wound around a tire axis. In the present embodiment, 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, for example, 0.3 to 3.5 mm. 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. 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. The covering rubber 4a can be made of any known rubber material such as a rubber material usually used for belt coating rubber.

Here, "tire contact width" means that the tire is applied to the outermost position in the tire width direction of the contact surface when the tire is mounted on the applicable rim, filled with the specified internal pressure, and the maximum load is applied. Mounted on the rim, filled with the specified internal pressure, and defined as the distance in the tire width direction between the ground contact edges in a no-load state.
In addition, other dimensions in the present specification are measured in a state in which a tire is mounted on an applicable rim, filled with a specified internal pressure, and 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.

As another embodiment, the belt 4 may be a spiral belt in which a cord 4b covered with a coating resin 4a that is a coating material is spirally wound in the tire circumferential direction. Also in this case, the belt 4 is preferably a single layer. It is because it is preferable from a viewpoint of weight reduction. Also in this case, the width of the belt 4 in the tire width direction can be, for example, 90 to 120% of the tire ground contact width. Also in this case, the thickness (maximum thickness) of the belt 4 is not particularly limited, but may be, for example, 0.3 to 3.5 mm. In this case as well, any known material can be used for the cord 4b. 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. 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. 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 (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 4a that covers the cord 4b is preferably 50 MPa or more. The tensile modulus of the coating resin 4a that covers the cord 4b is preferably 1000 MPa or less. 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.

Further, as shown in FIG. 1, the tire 1 includes a resin member 6 that continuously extends in the tire width direction, which is plate-shaped in this example, on the inner side in the tire radial direction of the belt 4. In this embodiment, the resin member 6 is disposed on the inner side in the tire radial direction of the belt 4, but the resin member 6 may be disposed on the outer side in the tire radial direction of the belt 4. As shown in FIG. 1, in the present embodiment, the width of the resin member 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. The width of the resin member 6 in the tire width direction can be, for example, 80 to 130% of the tire ground contact width. The resin of the resin member 6 can be the same type of resin as the case where the coating material 4b of the belt cord 4a is a resin, but a different type of resin can also be used.

In the tire 1 of the present embodiment, short fibers oriented in a predetermined direction inclined with respect to the tire circumferential direction are arranged in the resin member 6. The predetermined direction can be ± 80 ° or less with respect to the tire width direction, preferably ± 45 ° or less, particularly preferably ± 20 ° or less, and ± 10 ° or less. It is most preferable (in this embodiment, the direction is a direction inclined at ± 20 ° or less with respect to the tire width direction). In order to orient the short fibers, the short fibers can be oriented in the injection or extrusion direction by injecting or extruding a molten resin containing the short fibers.
As the short fiber, an organic short fiber or an inorganic short fiber can be used. Examples of the organic short fiber include polyamide-based, polyester-based, polyolefin-based, polyvinyl alcohol-based, and cellulose-based short fibers. On the other hand, short fibers such as iron, copper, aluminum, and carbon can be used as the inorganic short fibers. These short fibers may be used individually by 1 type, and 2 or more types may be mixed and used for them.
In the present embodiment, the fibers (short fibers) extend at an angle of 10 ° or less with the “predetermined direction”.
Hereinafter, the effect of the pneumatic tire of this embodiment is explained.

In the pneumatic tire of the present embodiment, first, since the resin member 6 is disposed in addition to the belt 4, the rigidity of the belt 4 can be sufficiently reinforced and enhanced, and the steering stability and the like can be improved.
Furthermore, in the pneumatic tire of the present embodiment, since the short fibers oriented in a predetermined direction inclined with respect to the tire circumferential direction are arranged in the resin member 6, the rigidity in the tire width direction of the resin member 6 is increased. The resin member 6 bears the tensile force in the tire width direction that occurs when the protrusion penetrates, and thus the protrusion penetration resistance can be improved. In the present embodiment, since the short fibers are oriented in a direction inclined at an angle of ± 20 ° or less with respect to the tire width direction, the rigidity and the rigidity in the tire width direction are particularly enhanced to effectively obtain the above-described effects. be able to. Further, the tensile force in the tire width direction is more intense on the inner side in the tire radial direction. In the present embodiment, the resin member 6 is disposed on the inner side in the tire radial direction of the belt 4, so that the tire can be more effectively used. The resin member 6 can bear the tensile force in the width direction. Further, as compared with the case of reinforcing with a member different from the resin member 6, it is not necessary to increase the number of manufacturing steps and the weight of the other member, or the material of the resin member 6 itself is highly rigid. Compared with the case where it makes, the deterioration of riding comfort, the crack of the resin member 6 at the time of large deformation, etc. can be suppressed.
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, it is preferable to use a short fiber having a length of 10 mm or less as the fiber as in the above embodiment. This is because the longer the fiber length, the better the impact strength, but the fiber bundle remains at the time of molding and the problem of dispersibility remains. On the other hand, in the present invention, a long fiber having a length of more than 10 mm can be used.

In the pneumatic tire of the present invention, the covering material 4a of the cord 4b of the belt 4 is preferably rubber. It is because it is excellent in manufacturability. Further, when the coating material 4a is rubber, the protrusion penetration resistance can be effectively obtained. On the other hand, as described above, the covering material 4a of the cord 4b of the belt 4 is preferably made of resin. This is because the resin has higher rigidity than the weight.

In the pneumatic tire of the present invention, the predetermined direction inclined with respect to the tire circumferential direction is preferably ± 20 ° or less, and most preferably ± 10 ° or less with respect to the tire width direction. This is because the rigidity in the tire width direction of the resin member 6 can be further improved.

In the pneumatic tire of the present invention, the resin member 6 is preferably arranged on the inner side in the tire radial direction of the belt 4. By arranging the resin member 6 having oriented short fibers in a place where the tensile force in the tire width direction is more strongly generated, the resin member 6 bears the tensile force in the tire width direction more effectively, This is because the protrusion penetration resistance can be effectively improved.

In the present invention, the fiber (short fiber) content in the resin member 6 is preferably in the range of 0.1 to 45% by weight. By making the content of the fiber (short fiber) 0.1% by weight or more, the above-mentioned reinforcing effect by the fiber (short fiber) can be more reliably exhibited, while the content of the fiber (short fiber) is included. This is because when the amount is 45% by weight or less, deterioration of ride comfort can be prevented.
In the present invention, the fibers (short fibers) are preferably arranged uniformly throughout the resin member 6 within the above-described content range, for example, but a part of the resin member 6 (for example, the tire width direction) It may be arranged only in the central part or one end part or both end parts in the tire width direction).

When the fiber is a short fiber having a length of 10 mm or less, the length of the short fiber is preferably 0.01 mm or more in order to obtain the effect of the above orientation more reliably.

When an inorganic short fiber, particularly a metal short fiber is used as the short fiber, it is preferable to have a coating layer on the surface of the metal short fiber from the viewpoint of improving the adhesiveness between the resin and the metal short fiber. The coating layer is preferably an arbitrary adhesive layer having adhesiveness between the resin and the short metal fibers. By providing such a coating layer, it is also possible to suppress a decrease in durability of the resin member 6 due to contact between short fibers during production or the like.

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 embodiment shown in FIG. 1, the resin member 6 is disposed on the inner side in the tire radial direction of the belt 4, but may be disposed on the outer side in the tire radial direction of the belt 4. In the embodiment shown in FIG. 1, the width of the resin member 6 in the tire width direction is larger than the width of the belt 4 in the tire width direction, but the width of the resin member 6 in the tire width direction is the tire width of the belt 4. It may be smaller than the width in the direction or may be substantially the same width. Further, the thickness of the resin member 6 can be made larger, substantially the same or smaller than the thickness of the belt 4. In the embodiment shown in FIG. 1, the resin member 6 is a plate-like member extending continuously in the tire width direction, but the resin member 6 is intermittent in the tire width direction (for example, intermittent). It may be a plate-like one extending in general.
In the embodiment shown in FIG. 1, the circumferential main grooves 8 (four in the illustrated example) continuously extending in the tire circumferential direction are provided, but the number of the circumferential main grooves 8 is particularly limited. Alternatively, the circumferential main groove 8 may not be provided.

1: pneumatic tire, 2: bead part, 2a: bead core, 3: carcass, 4: belt, 4a: coating resin (coating rubber, coating resin), 4b: cord, 5: tread, 6: resin member, 8: Circumferential main groove, CL: tire equatorial plane

Claims

A belt in which a cord covered with a coating material is spirally wound in the tire circumferential direction;
A resin member disposed on the outer side or the inner side in the tire radial direction of the belt, and
A pneumatic tire characterized in that fibers oriented in a predetermined direction inclined with respect to the tire circumferential direction are arranged in the resin member.
The pneumatic tire according to claim 1, wherein the fiber is a short fiber having a length of 10 mm or less.
The pneumatic tire according to claim 1 or 2, wherein the coating material is rubber.
The pneumatic tire according to any one of claims 1 to 3, wherein the predetermined direction is in a range of ± 20 ° or less with respect to a tire width direction.
The pneumatic tire according to any one of claims 1 to 4, wherein the resin member is disposed on an inner side in the tire radial direction of the belt.