WO2019230496A1

WO2019230496A1 - Pneumatic tire

Info

Publication number: WO2019230496A1
Application number: PCT/JP2019/020079
Authority: WO
Inventors: 正之有馬
Original assignee: 株式会社ブリヂストン
Priority date: 2018-05-31
Filing date: 2019-05-21
Publication date: 2019-12-05
Also published as: JP2019209746A

Abstract

A pneumatic tire 1 according to the present invention is characterized by comprising: a belt 4 wherein a cord 4b, which is helically wound in the tire circumferential direction, is covered by a rubber 4a; an outer resin sheet 6 which is formed of a resin and is arranged to be superposed on the belt 4 on the outside of the belt 4 in the tire radial direction; and an inner resin sheet 7 which is formed of a resin and is arranged to be superposed on the belt 4 on the inside of the belt 4 in the tire radial direction.

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).

In addition, the belt is formed by covering a cord spirally wound in the tire circumferential direction with rubber, and by arranging a resin sheet on one side of the belt in the tire radial direction, the belt can be bent. A technique for reinforcing rigidity has also been proposed (for example, Patent Document 2).

Japanese Patent Laid-Open No. 10-035220 Special table 2013-539734 gazette

However, in the configuration in which the resin sheet is arranged on one side in the tire radial direction of the belt, considering the increase in weight due to the resin sheet and the arrangement space, the thickness of the resin sheet is sufficient to obtain sufficient bending rigidity. It is difficult. Therefore, there has been a problem that sufficient resistance cannot be obtained with respect to inputs such as protrusions such as stones, steps, curbs and road fences.

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 is a belt in which a cord wound spirally in the tire circumferential direction is covered with rubber,
An outer resin sheet made of resin and arranged to overlap the outer side of the belt in the tire radial direction;
An inner resin sheet made of resin and arranged overlapping the inner side in the tire radial direction of the belt;
It is characterized by having.

Here, the tire width direction dimension of the belt and other dimensions in the present specification are measured in a state in which the tire is mounted on an applicable rim, filled with a specified internal pressure, and in a no-load state.
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 loaded, Means the distance in the tire width direction between the ground contact ends in a state of being loaded with a specified internal pressure and in a no-load state. The “center in the tire width direction” is the center in the tire width direction between the ground contact points (the position of the tire equator) when the tire is mounted on the applicable rim, filled with the specified internal pressure, and is in an unloaded state. Means.

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, 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. FIG. 2 is a schematic partial sectional view showing a belt, an outer resin sheet, an inner resin sheet, and a carcass in the embodiment shown in FIG. 1. It is a tire width direction schematic sectional drawing which shows the pneumatic tire which concerns on the modification of embodiment shown in FIG.

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

A pneumatic tire 1 (hereinafter also simply referred to as “tire 1”) according to an embodiment of the present invention shown in FIG. 1 is mounted on a rim of a wheel for a passenger car, for example, and a gas such as air or nitrogen is supplied at a specified internal pressure. It is a rubber radial tire that is filled and used, and includes a bead core 2 a embedded in a pair of bead portions 2 and a carcass 3 straddling 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. A belt reinforcing layer that reinforces the belt 4 over its entire width may be disposed between the belt 4 and the tread 5. Further, a belt reinforcing layer that covers the end of the belt 4 in the tire width direction may be provided between the belt 4 and the tread 5. 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 can also have an asymmetric configuration.

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 2a are not particularly limited, or a structure without the bead core 2a may be employed. 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 the present embodiment, the belt 4 is a spiral belt in a state where the cord 4b covered with the rubber 4a, that is, the rubber-coated cord is spirally wound in the tire circumferential direction (around the tire axis). Cord 4b Rubber 4a This belt 4 is formed by winding a rubber 4a cord 4b cord 4b rubber 4a rubber 4a rubber-coated cord so as to be in close contact with each other in the tire width direction, and then integrating the adjacent rubber 4a by vulcanization. be able to. Note that the rubber-coated cord may include a plurality of cords 4b. Since the belt 4 configured as described above is configured as a spiral belt, the diameter growth hardly occurs, so that the high-speed running performance of the tire 1 can be improved.

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 contact width, but the width of the belt 4 in the tire width direction is larger than 100% of the tire contact width, and the belt 4 It is preferable that both ends in the tire width direction are provided outside the tire ground contact end on the outer side in the tire width direction and provided over the entire range of the tire ground contact width. In addition, the frequency | count of winding to the tire peripheral direction of the code | cord | chord 4b can be suitably changed according to a tire width dimension.

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. Moreover, as the cord 4b, a cord made of organic fiber or carbon fiber can be used.

As the rubber 4a, any rubber (an organic polymer substance exhibiting rubber elasticity at room temperature) can be used, and for example, those used as tire materials can be used.

As shown in FIGS. 1 and 2, the tire 1 of this embodiment includes an outer resin sheet 6. The outer resin sheet 6 is made of sheet-shaped (plate-shaped) resin, and is disposed on the outer side in the tire radial direction of the belt 4. Further, the tire 1 of the present embodiment includes an inner resin sheet 7. The inner resin sheet 7 is made of sheet-shaped (plate-shaped) resin, and is disposed so as to overlap the inner side in the tire radial direction of the belt 4. Since the outer resin sheet 6 and the inner resin sheet 7 are spaced apart from each other in the tire radial direction with the belt 4 in between, the outer resin sheet 6 and the inner resin sheet 7 having a small thickness can prevent the protrusions from penetrating. High bending rigidity can be obtained. That is, in the present embodiment, the outer resin sheet 6 and the inner resin sheet 7 are disposed with a gap in the tire radial direction with the belt 4 interposed therebetween, so the thickness of the outer resin sheet 6 and the thickness of the inner resin sheet 7 are arranged. As compared with the configuration in which the resin sheet having the total thickness is overlapped only on one side in the tire radial direction of the belt 4, the bending rigidity with respect to the penetration of the protrusions can be further increased. Therefore, the belt 4 is reinforced so that the outer resin sheet 6 and the inner resin sheet 7 have sufficient bending rigidity without increasing the overall thickness of the belt 4, the outer resin sheet 6, and the inner resin sheet 7. In addition, it is possible to improve resistance to protrusions (projection resistance) such as stones, steps, curbs, and road fences. Further, by reinforcing the belt rigidity with the outer resin sheet 6 and the inner resin sheet 7, it is possible to improve the steering stability of the vehicle on which the tire 1 is mounted. Furthermore, since the belt 4 is configured to be sandwiched between the outer resin sheet 6 and the inner resin sheet 7, the rubber 4a constituting the belt 4 receives a shearing force in the tire radial direction when the protrusion penetrates. It is possible to prevent tearing between adjacent cords 4b.

As described above, in the present embodiment, a configuration in which the resin sheet having the total thickness of the outer resin sheet 6 and the inner resin sheet 7 is disposed so as to overlap only on one side in the tire radial direction of the belt 4. Since the bending rigidity with respect to the penetration of the protrusions can be further increased, the thickness of the resin sheet necessary for obtaining the desired bending rigidity can be further reduced. Therefore, it is possible to reinforce the belt 4 so as to have a desired bending rigidity while reducing the weight, and the rolling resistance of the tire 1 can be reduced. Moreover, since the bending rigidity can be reduced by making the outer resin sheet 6 to the inner resin sheet 7 thinner, the riding comfort of the vehicle in which the tire 1 is used can be enhanced.

It is preferable that the outer resin sheet 6 and the inner resin sheet 7 are each fixed to the surface of the belt 4 by adhesion or welding. By adopting a configuration in which the outer resin sheet 6 and the inner resin sheet 7 are fixed to the surface of the belt 4, the outer resin sheet 6 and the inner resin sheet 7 are integrated with the belt 4 interposed therebetween and are constrained to each other. Bending rigidity can be further increased. Thereby, protrusion penetration resistance can be improved more effectively.

The width of the outer resin sheet 6 in the tire width direction is not particularly limited, but is preferably equal to or less than the width of the belt 4 in the tire width direction (same in the present embodiment shown in FIG. 1). More specifically, the width of the outer resin sheet 6 in the tire width direction is preferably 10 to 100% of the width of the belt 4 in the tire width direction. By setting the width of the outer resin sheet 6 in the tire width direction to 10 to 100% of the width of the belt 4 in the tire width direction, the protrusion penetration resistance can be improved while suppressing an increase in the weight of the tire 1.

The outer resin sheet 6 is preferably arranged with the center position in the tire width direction aligned with the center position in the tire width direction of the belt 4, but at least at the center in the tire width direction, the outer resin sheet 6 is disposed so as to overlap the belt 4. The center position in the tire width direction may be shifted from the center position in the tire width direction of the belt 4.

The width of the inner resin sheet 7 in the tire width direction is not particularly limited, but is preferably the same as the width of the belt 4 in the tire width direction as in the present embodiment shown in FIG. By adopting a configuration in which the inner resin sheet 7 is disposed so as to overlap the entire range in the tire width direction on the inner side in the tire radial direction of the belt 4 where the tensile force in the tire width direction applied when the protrusion penetrates is increased. Can be reliably supported by the inner resin sheet 7, and the protrusion penetration resistance can be improved more effectively. The width of the inner resin sheet 7 in the tire width direction is made larger than the width of the belt 4 in the tire width direction, and both ends of the inner resin sheet 7 in the tire width direction are larger than both ends of the belt 4 in the tire width direction. It can also be set as the structure located in a tire width direction outer side. Further, the width of the inner resin sheet 7 in the tire width direction can be made larger than the width of the outer resin sheet 6 in the tire width direction.

Although the thickness (maximum thickness) of the outer resin sheet 6 and the thickness (maximum thickness) of the inner resin sheet 7 are not particularly limited, for example, each may be 0.5 mm or more. The total thickness of the outer resin sheet 6 and the inner resin sheet 7 is preferably 1.0 to 6.0 mm, more preferably 1.0 to 4.0 mm. More preferably, the thickness is set to 0.0 to 3.0 mm. Thereby, protrusion penetration resistance can be improved, suppressing the weight increase of the pneumatic tire 1. FIG. In any case, the thickness of the outer resin sheet 6 and the thickness of the inner resin sheet 7 can be made the same, but the inner resin sheet 7 is made thicker than the outer resin sheet 6. Is preferred. Since the tensile force in the tire width direction applied when the protrusion penetrates is larger on the inner side in the tire radial direction than on the outer side in the tire radial direction of the belt 4, the total thickness of the outer resin sheet 6 and the inner resin sheet 7 is increased. If the same, the thickness of the inner resin sheet 7 is larger than the thickness of the outer resin sheet 6, so that the tensile force in the tire width direction applied when the protrusion penetrates can be more effectively supported. It is. The inner resin sheet 7 may be thinner than the outer resin sheet 6.

As the resin of the outer resin sheet 6 and the inner resin sheet 7, 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 is used. You can also. 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 modulus of elasticity of the resin of the outer resin sheet 6 and the inner resin sheet 7 (specified in JIS K7113: 1995) is preferably 100 MPa or more. This is because the outer resin sheet 6 or the inner resin sheet 7 can be lightened and the rigidity can be increased. Moreover, it is preferable that the tensile elasticity modulus of resin of the outer side resin sheet 6 and the inner side resin sheet 7 shall be 1000 Mpa or less, respectively. This is because the ride comfort can be maintained well. Note that the resin here does not include rubber (an organic polymer substance exhibiting rubber elasticity at room temperature).

In this embodiment, a thermoplastic elastomer is used as the resin of the outer resin sheet 6 and the inner resin sheet 7. By using a thermoplastic elastomer as the resin of the outer resin sheet 6 and the inner resin sheet 7, the outer resin sheet 6 and the inner resin sheet 7 can be easily formed into a shape corresponding to the belt 4. The resin of the outer resin sheet 6 and the resin of the inner resin sheet 7 are preferably the same as each other, but may be different from each other.

When a thermoplastic resin is used as the resin of the outer resin sheet 6 and the inner resin sheet 7, the thermoplastic resin generally has a higher rigidity than the weight of rubber or the like, and therefore the outer resin sheet 6 And the rigidity with respect to the tire width direction can be ensured, reducing the weight of the inner resin sheet 7.

As shown in FIG. 1, the tire 1 can be configured such that the tread 5 is provided with two or more circumferential main grooves 8 that continuously extend linearly in the tire circumferential direction. In the present embodiment, the tread 5 is provided with a total of four circumferential main grooves 8, two at a time in the tire width direction half with the tire equatorial plane CL as a boundary. The number and arrangement of the circumferential main grooves 8 can be arbitrary, and the tread 5 can be configured not to be provided with the circumferential main grooves 8.

Here, the “circumferential main groove” means a groove having a groove width (opening width) of 2 mm or more. Further, the “groove width” is 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. The “circumferential main groove” may extend linearly, or may extend in a curved shape or a zigzag shape.

As described above, when two or more circumferential main grooves 8 are provided in the tread 5, both ends of the outer resin sheet 6 in the tire width direction are centered in the tire width direction of the tread 5 (tires). It is preferable that the configuration is located outside the two circumferential main grooves 8 adjacent to each other with the equator plane CL) interposed therebetween. In this case, the outer resin sheet 6 has a width in the tire width direction that is wider than the interval between the edges on the outer side in the tire width direction of the two circumferential main grooves 8 adjacent to each other across the center in the tire width direction of the tread 5. It is preferable that the two circumferential main grooves 8 are arranged in a region including the inner portion in the tire radial direction. As a result, when two or more circumferential main grooves 8 are provided in the tread 5, two circumferential main grooves 8 adjacent to each other across the center in the tire width direction where the protrusion penetration resistance is weakest are provided. The rigidity of the tire 1 at the raised portion can be reinforced by the outer resin sheet 6 and the inner resin sheet 7 to improve the protrusion penetration resistance more effectively.

As shown in FIG. 3 as a modified example, the present invention can also be applied to a tire 1 configured as a run-flat tire. The tire 1 shown in FIG. 3 includes a reinforcing rubber layer 10 on each of the side wall portions 9 on both sides in the tire width direction, and is configured as a run flat tire. The reinforcing rubber layer 10 has a crescent-shaped cross section, is disposed inside the carcass 3 in the tire width direction, and is embedded in the sidewall portion 9 so as not to be exposed on the tire inner surface. By providing the reinforcing rubber layers 10 on the respective sidewall portions 9, the tire 1 can be used when the internal pressure becomes equal to or lower than a specified internal pressure (for example, atmospheric pressure) due to puncture or the like when the tire 1 is attached to the rim. Even if it exists, the load of a vehicle can be supported by the side wall part 9 in which the reinforcement rubber layer 10 was provided, and it can drive | work safely for a fixed distance at predetermined speed.

The run-flat tire can run even if the air escapes and the internal pressure falls below the specified internal pressure. However, since the force toward the outer side in the tire radial direction due to the internal pressure is not applied to the belt 4, buckling is likely to occur. . On the other hand, in the tire 1 according to the modification of the present embodiment shown in FIG. 3, as described above, the outer resin sheet 6 is arranged on the outer side in the tire radial direction of the belt 4 and the inner side in the tire radial direction of the belt 4. Since the inner resin sheet 7 is overlapped and the bending rigidity of the belt 4 is reinforced, the penetration resistance to protrusions can be improved, and the tire 1 configured as a run-flat tire is in a run-flat running (middle). It is possible to prevent the occurrence of buckling and to ensure the running performance of the tire 1 during the run-flat running in which the internal pressure is not more than the specified internal pressure.

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 tire 1 is for a passenger car, but may be used for a vehicle other than a passenger car. The tire 1 may be a normal tire (summer tire) used in seasons other than winter, or may be a studless tire (winter tire) suitable for snowy roads and frozen roads.

1: pneumatic tire, 2: bead part, 2a: bead core, 3: carcass, 4: belt, 4a: rubber, 4b: cord, 5: tread, 6: outer resin sheet, 7: inner resin sheet, 8: circumference Direction main groove, 9: sidewall portion, 10: reinforcing rubber layer, CL: tire equatorial plane

Claims

A belt in which a cord spirally wound in the tire circumferential direction is covered with rubber;
An outer resin sheet made of resin and arranged to overlap the outer side of the belt in the tire radial direction;
An inner resin sheet made of resin and arranged overlapping the inner side in the tire radial direction of the belt;
A pneumatic tire characterized by comprising:
The pneumatic tire according to claim 1, wherein the outer resin sheet and the inner resin sheet are each fixed to the belt.
The pneumatic tire according to claim 1 or 2, wherein a width of the outer resin sheet in the tire width direction is 10 to 100% of a width of the belt in the tire width direction.
The pneumatic tire according to any one of claims 1 to 3, wherein a total thickness of the outer resin sheet and the inner resin sheet is 1.0 to 6.0 mm.
The pneumatic tire according to any one of claims 1 to 4, wherein a tensile elastic modulus of the resin of the outer resin sheet and a tensile elastic modulus of the resin of the inner resin sheet are 100 to 1000 MPa, respectively.
The pneumatic tire according to any one of claims 1 to 5, wherein the outer resin sheet and the inner resin sheet are each made of a thermoplastic elastomer.