tire

Abstract

To provide a tire that can make both riding comfort during high-speed travelling and durability compatible.SOLUTION: A tire 1 comprises a belt layer 7 and a band layer 9. The belt layer 7 includes at least one belt ply 7B. The belt ply 7B includes belt cords 7a made of steel single wires. The band layer 9 includes at least one band ply 9A. the band ply 9A includes band cords 9a arranged at an angle of 5° or less with respect to a tire circumferential direction. A gauge s which is a distance in a tire radial direction between surfaces of the belt cords 7a of the belt ply 7B which are adjacent in a tire radial direction and surfaces of the band cords 9a of the band ply 9A is 0.1-0.3 mm. A value (d1+d2) / s determined by dividing a sum of a diameter d1(mm) in the tire radial direction of the belt cords 7a and a diameter d2(mm) in the tire radial direction of the band cords 9a by the gauge s (mm) is 4.0-13.0.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a tire having a belt layer and a band layer. [Background technology]

[0002] Conventionally, tires having a belt layer and a band layer on the radially inner side of the tread portion are known. For example, Patent Document 1 below proposes a tire in which a belt consisting of two or more layers contains cords, and by specifying the gauge between the cords of two adjacent layers, it is possible to achieve both noise performance and low fuel consumption performance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-177838 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in recent years, with improvements in vehicle performance and the development of infrastructure such as expressways, further improvements in ride comfort and durability during high-speed driving have been desired even for the tire of Patent Document 1.

[0005] The present disclosure has been devised in view of the above circumstances, and has as its main object to provide a tire that can achieve both ride comfort performance and durability performance during high-speed driving. [Means for solving the problem]

[0006] The present disclosure relates to a tire having a belt layer and a band layer, wherein the belt layer includes at least one belt ply, the belt ply including a belt cord made of a steel solid wire, the band layer including at least one band ply, the band ply including a band cord arranged at an angle of 5° or less with respect to the tire circumferential direction, a gauge which is the tire radial distance between a surface of the belt cord of the belt ply and a surface of the band cord of the band ply which are adjacent in the tire radial direction is 0.1 to 0.3 mm, and a value obtained by dividing the sum of the tire radial diameter (mm) of the belt cord and the tire radial diameter (mm) of the band cord by the gauge (mm) is 4.0 to 13.0. [Effects of the Invention]

[0007] The tire of the present disclosure has such a belt layer and band layer, and thus can achieve both ride comfort performance and durability performance during high-speed driving. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of one embodiment of a tire of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view of a belt layer and a band layer according to the present embodiment. [Figure 3] FIG. 10 is a cross-sectional view of a belt layer and a band layer according to another embodiment. [Figure 4] FIG. 2 is a schematic diagram of a belt cord. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. 1 shows a tire meridian cross section including a rotation axis of a tire 1 of this embodiment in a normal state. Here, the "normal state" refers to a state in which, if the tire 1 is a pneumatic tire, the tire 1 is mounted on a normal rim, the tire pressure is adjusted to a normal level, and no load is applied. Unless otherwise specified below, the dimensions of each part of the tire 1 are values ​​measured in this normal state.

[0010] If there is a standard system that includes the standard on which tire 1 is based, a "genuine rim" is a rim that is determined for each tire by that standard, for example, a "standard rim" for JATMA, a "design rim" for TRA, or a "measuring rim" for ETRTO. If there is no standard system that includes the standard on which tire 1 is based, a "genuine rim" is a rim that can be mounted on a rim and does not cause air leakage, and that has the smallest rim diameter and narrowest rim width among those rims.

[0011] "Normal internal pressure" is the air pressure set for each tire by a standard system that includes the standard on which tire 1 is based, if there is such a system; for JATMA, it is the "maximum air pressure," for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES," and for ETRTO, it is the "INFLATION PRESSURE." If there is no standard system that includes the standard on which tire 1 is based, the "normal internal pressure" is 250 kPa for passenger car tires.

[0012] The tire 1 of this embodiment is suitable for use as a passenger car tire. In this specification, a passenger car tire refers to a pneumatic rubber tire designed to be mounted on a four-wheeled vehicle, with a standard load of 1000 kg or less.

[0013] In addition, there are no particular limitations on passenger car tires as long as the normal load is 1000 kg or less, but from the viewpoint of suppressing excessive deformation in the tread portion, it is preferable that the normal load be 900 kg, more preferably 750 kg, and even more preferably 700 kg.

[0014] "Normal load" is the load specified for each tire by each standard in the standard system, including the standard on which tire 1 is based, and is the "maximum load capacity" in the case of JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" in the case of TRA, and the "LOAD CAPACITY" in the case of ETRTO.

[0015] The tire 1 is not limited to a passenger vehicle tire, but can be applied to, for example, a heavy-duty tire, a motorcycle tire, a racing tire, etc. The tire 1 having the belt layer 7 and band layer 9 described later can be applied to various tires, such as a non-pneumatic tire that is not filled with pressurized air inside.

[0016] 1, the tire 1 of this embodiment includes a tread portion 2 extending annularly, a pair of sidewall portions 3 extending on both sides of the tread portion 2, and a pair of bead portions 4 extending continuous to the sidewall portions 3. The tire 1 of this embodiment has a toroidal carcass 6 extending across between bead cores 5 of the pair of bead portions 4, and a belt layer 7 arranged outside the carcass 6 in the tire radial direction and inside the tread portion 2 in the tire radial direction a.

[0017] The tread portion 2, for example, has an outer surface 2a that forms a contact surface that comes into contact with the road surface during running. The profile of the outer surface 2a of the tread portion 2, in a tire meridian cross section, is, for example, a single arc or a combination of arcs with multiple curvatures.

[0018] The tread portion 2 desirably includes at least one elastomer layer. The tread portion 2 may have, for example, two or more elastomer layers laminated in the tire radial direction a, or may have multiple elastomer layers in the tire axial direction.

[0019] The elastomer layer of the tread portion 2 may be appropriately provided with, for example, circumferential grooves extending in the tire circumferential direction, lateral grooves extending in the tire axial direction, sipes with a groove width of 2 mm or less, etc. Examples of circumferential grooves include those that extend linearly and those that extend zigzag.

[0020] Examples of the elastomer layer of the tread portion 2 include natural rubber, isoprene-based rubbers such as isoprene rubber, butadiene rubber, styrene-butadiene rubber, styrene-isoprene-butadiene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, and butyl rubber, and diene-based rubbers such as styrene-butadiene block copolymers and styrene-isoprene-styrene copolymers. Among these, diene-based rubbers are preferably used for the elastomer layer of the tread portion 2.

[0021] The sidewall portion 3 desirably includes at least one elastomer layer. The sidewall portion 3 may have, for example, two or more elastomer layers laminated in the tire axial direction, or may have multiple elastomer layers in the tire radial direction a. The elastomer layer of the sidewall portion 3 may be made of the same component as the elastomer layer of the tread portion 2, or may be made of a different component.

[0022] The boundary surface between the elastomer layer of the tread portion 2 and the elastomer layer of the sidewall portion 3 is, for example, located more outward in the tire radial direction a than the inner end side at the outer end side in the axial direction of the tire. The boundary surface between the elastomer layer of the tread portion 2 and the elastomer layer of the sidewall portion 3 may be, for example, located more inward in the tire radial direction a than the inner end side at the outer end side in the axial direction of the tire.

[0023] The carcass 6 includes at least one carcass ply 6A, one carcass ply 6A in this embodiment. The carcass ply 6A is formed of an elastomer layer including carcass cords (not shown) arranged at an angle of 75 to 90 degrees relative to the tire circumferential direction, for example. As the carcass cords, for example, organic fiber cords such as aromatic polyamide (aramid), rayon, polyester, etc. can be used. Here, in this specification, "A to B" means "greater than or equal to A and less than or equal to B."

[0024] The carcass ply 6A includes, for example, a main body portion 6a extending from the tread portion 2 through the sidewall portion 3 to the bead cores 5 of the bead portions 4, and turned-up portions 6b continuing to the main body portion 6a and folded back around the bead cores 5 from the inner side to the outer side in the axial direction of the tire. The turned-up portions 6b may have, for example, outer ends in the tire radial direction extending to the belt layer 7. Between the main body portion 6a and the turned-up portions 6b of the carcass ply 6A, for example, a bead apex 8 extending from the bead cores 5 to the outer side in the tire radial direction is disposed. The bead apex 8 is formed, for example, from an elastomer layer.

[0025] The bead portion 4 may include, for example, a bead reinforcing layer (not shown) provided on the axially outer side of the turned-up portion 6b of the carcass 6. The bead reinforcing layer may be formed of, for example, an elastomer layer having the same components as the bead apex 8, or may be formed of an elastomer layer having a different component.

[0026] The bead portion 4 may include, for example, a chafer (not shown) provided axially outward of the turned-up portion 6b of the carcass 6. When a bead reinforcing layer and a chafer are provided, it is desirable that the chafer be disposed axially outward of the bead reinforcing layer.

[0027] The tire 1 of this embodiment has an inner liner 10 provided inside the carcass 6. The inner liner 10 is preferably formed from an air-impermeable elastomer layer. Examples of the elastomer layer of the inner liner 10 include butyl rubber and halogenated butyl rubber. Such an inner liner 10 can maintain the air pressure filled in the tire 1.

[0028] The belt layer 7 includes at least one, preferably two or more, and in this embodiment, two belt plies 7A and 7B. The two belt plies 7A and 7B include, for example, a first belt ply 7A located on the radially inner side of the tire and a second belt ply 7B located on the outer side of the first belt ply 7A. Such a belt layer 7 can increase the rigidity of the tread portion 2 and improve the durability of the tire 1 during high-speed running.

[0029] The tire 1 has a band layer 9 including at least one band ply 9A, one in this embodiment, arranged on the inner side of the tread portion 2 in the tire radial direction a. Such a band layer 9 is useful for achieving both ride comfort performance and durability performance of the tire 1 during high-speed running. This is because the band ply 9A improves the restraint of the tread portion 2, and is expected to reduce the amount of deformation of the tread portion 2 during high-speed running and suppress heat generation.

[0030] Fig. 2 is a cross-sectional view of the belt layer 7 and the band layer 9 of this embodiment, and Fig. 3 is a cross-sectional view of the belt layer 7 and the band layer 9 of another embodiment. As shown in Fig. 2 and Fig. 3, the belt plies 7A and 7B of the belt layer 7 of this embodiment include belt cords 7a made of solid steel wires and an elastomer composition 7G that covers the belt cords 7a.

[0031] Such a belt layer 7 is useful for achieving both ride comfort and durability performance of the tire 1 during high-speed running. This is because the belt cord 7a is a steel single wire and is unlikely to stretch even if the tire radial diameter is reduced to reduce weight, and therefore it is expected to stabilize the shape of the tread portion 2 during high-speed running and suppress heat generation.

[0032] The elastomer composition 7G of the belt plies 7A and 7B of this embodiment exhibits rubber elasticity. Examples of the elastomer composition 7G include a rubber composition and a thermoplastic elastomer composition. When the elastomer composition 7G is a rubber composition, examples of the rubber component include isoprene-based rubber, butadiene-based rubber, styrene-butadiene rubber, nitrile rubber, and butyl rubber. When the elastomer composition 7G is a thermoplastic elastomer composition, examples of the elastomer include thermoplastic polyurethane, styrene-butadiene block copolymer, styrene-ethylene-butylene-styrene block copolymer, and other block copolymers.

[0033] The belt cord 7a of the present embodiment is plated or ternary plated. Examples of the plating include zinc, copper, etc. Examples of the ternary plating include zinc, copper, cobalt, etc.

[0034] Such belt cord 7a has good adhesion to the elastomer composition 7G, and the belt cord 7a and the elastomer composition 7G can generate a stress in cooperation with each other even during high-speed driving, thereby improving the durability performance of the tire 1 during high-speed driving.

[0035] The belt cords 7a are arranged at an angle of, for example, 10 to 30 degrees with respect to the tire circumferential direction. The belt cords 7a of the first belt ply 7A and the belt cords 7a of the second belt ply 7B are desirably inclined at the same angle but in opposite directions with respect to the tire circumferential direction. Here, the angle of the belt cords 7a is the angle in the tire 1 in a normal state, and can be confirmed, for example, by partially peeling off the tread portion 2. Such a belt layer 7 can increase the rigidity of the tread portion 2 in a balanced manner and improve the durability performance of the tire 1 during high-speed running.

[0036] The band ply 9A of this embodiment includes band cords 9a arranged at an angle of 5° or less with respect to the tire circumferential direction, and an elastomer composition 9G that covers the band cords 9a. Here, the angle of the band cords 9a is the angle in the tire 1 in a normal state, and can be confirmed by, for example, partially peeling off the tread portion 2.

[0037] The elastomer composition 9G of the band ply 9A preferably exhibits rubber elasticity, similar to the elastomer composition 7G of the belt plies 7A and 7B. The elastomer composition 9G may be, for example, the same as the elastomer composition 7G.

[0038] In this embodiment, a gauge s, which is the distance in the tire radial direction between the surface of the belt cord 7a of the belt ply 7B and the surface of the band cord 9a of the band ply 9A adjacent in the tire radial direction, is 0.1 to 0.3 mm.

[0039] Such belt ply 7B and band ply 9A have a small gauge s between the belt cord 7a and the band cord 9a, and therefore can reduce the centrifugal force acting on the tread portion 2 during high-speed running, thereby improving the durability performance of the tire 1 during high-speed running. This is thought to be because the centrifugal force acting on the tread portion 2 can be reduced, suppressing the amount of deformation of the tread portion 2 and, in turn, suppressing heat generation.

[0040] In this embodiment, the sum (d1+d2) of the diameter d1 (mm) of the belt cord 7a in the tire radial direction a and the diameter d2 (mm) of the band cord 9a in the tire radial direction a divided by the gauge s (mm) ((d1+d2) / s) is 4.0 to 13.0.

[0041] Such belt ply 7B and band ply 9A can suppress a decrease in ride comfort of the tire 1 during high-speed running. This is thought to be because when the gauge s between the belt cord 7a and the band cord 9a is small, the sum (d1 + d2) of the diameter d1 of the belt cord 7a and the diameter d2 of the band cord 9a also becomes small. As a result, the tire 1 of this embodiment can achieve both ride comfort and durability during high-speed running.

[0042] The mechanism by which the effects of this embodiment are achieved is believed to be as follows, but it is not intended to be bound by the following theory.

[0043] That is, in the tire 1 of this embodiment, the belt cord 7a is formed of a steel solid wire. As a result, in this embodiment, it is possible to reduce the outer diameter of the cord compared to a stranded wire cord, which is thought to contribute to reducing the weight of the tire 1. Reducing the weight of the tire 1 helps improve fuel efficiency.

[0044] However, because the steel solid wire is not twisted, its contact area with the rubber is smaller than that of a twisted wire, and generally, the restraining force in the tire radial direction tends to be smaller. If the restraining force of the belt cord 7a is small, for example, the centrifugal force generated during high-speed running may cause the outer diameter to increase, which is called outer diameter growth, and this may increase the amount of deformation of the tread portion 2 and the amount of heat generated. Furthermore, in this case, the tread portion 2 is stretched thinly as the outer diameter grows, which may reduce the durability of the tire 1 during high-speed running.

[0045] Therefore, in the tire 1 of this embodiment, by specifying a small gauge s between the belt cord 7a and the band cord 8a, it is expected that the centrifugal force acting on the tread portion 2 will be reduced, the amount of deformation of the tread portion 2 will be suppressed, and heat generation will be suppressed. As a result, it is believed that the tire 1 of this embodiment can improve durability performance during high-speed running.

[0046] On the other hand, when the gauge s between the belt cord 7a and the band cord 8a is small, the cushioning properties of the tread portion 2 are suppressed, and generally, the ride comfort of the tire 1 tends to decrease. In the tire 1 of this embodiment, by specifying the value ((d1+d2) / s) within a certain range, the sum (d1+d2) also becomes small when the gauge s is small, and therefore the rigidity of the tread portion 2 in the tire radial direction can be moderately alleviated. As a result, it is believed that the tire 1 of this embodiment can achieve both improved durability during high-speed driving and ride comfort during high-speed driving.

[0047] Furthermore, in the tire 1 of this embodiment, when a large value of the gauge s is adopted within a specific range, the sum (d1+d2) also becomes large, which is thought to improve the restraint of the tread portion 2 and improve the overall performance of ride comfort and durability during high-speed driving.

[0048] The belt cord 7a and the band cord 9a in Fig. 2 have circular cross sections, while the belt cord 7a and the band cord 9a in Fig. 3 have flat cross sections. In this specification, "circular" means that the ratio of the major axis to the minor axis of the cross section is less than 1.05, and "flat" means that the ratio of the major axis to the minor axis of the cross section is 1.05 or more.

[0049] The diameter d1 of the belt cord 7a in the tire radial direction a is the diameter of the cross section if the belt cord 7a has a circular cross section as shown in Fig. 2. The diameter d1 of the belt cord 7a in the tire radial direction a is the diameter along the tire radial direction a if the belt cord 7a has a flat cross section as shown in Fig. 3.

[0050] Fig. 4 is a schematic diagram of a belt cord 7a. As shown in Fig. 4, when the belt cord 7a with a flat cross section is arranged at an angle with respect to the tire radial direction a, of the minor axis Sd and major axis Ld of the belt cord 7a with a flat cross section, the one with a smaller angle with respect to the tire radial direction a is set to the diameter d1 in the tire radial direction a. In Fig. 4, the angle θ1 of the minor axis Sd direction with respect to the tire radial direction a is smaller than the angle θ2 of the major axis Ld direction, so the minor axis Sd is set to the diameter d1 in the tire radial direction a.

[0051] The diameter d2 of the band cord 9a in the tire radial direction a is the diameter of the cross section if the band cord 9a has a circular cross section as shown in Fig. 2. The diameter d2 of the band cord 9a in the tire radial direction a is the diameter along the tire radial direction a if the band cord 9a has a flat cross section as shown in Fig. 3.

[0052] Although not shown in the figures, when the band cord 9a with a flat cross section is arranged at an angle with respect to the tire radial direction a, the diameter d2 in the tire radial direction a is set as the diameter of the minor axis or major axis of the band cord 9a with a flat cross section, whichever has a smaller angle with respect to the tire radial direction a (see FIG. 4).

[0053] 2 and 3, the belt cord 7a preferably has a diameter d1 in the tire radial direction a of 0.16 to 0.42 mm. Since the diameter d1 of the belt cord 7a in the tire radial direction a is small, the centrifugal force acting on the tread portion 2 during high-speed running can be reduced, and the tire 1 can achieve both good ride comfort and durability during high-speed running.

[0054] By setting the diameter d1 of the belt cord 7a to 0.16 mm or more, it is possible to improve the binding force of the tread portion 2 and improve the durability performance of the tire 1 during high-speed running. From this viewpoint, the diameter d1 of the belt cord 7a is more preferably 0.20 mm or more, and even more preferably 0.23 mm or more.

[0055] By setting the diameter d1 of the belt cord 7a to 0.42 mm or less, it is possible to suppress an increase in bending rigidity and improve the ride comfort performance of the tire 1 during high-speed running. From this viewpoint, the diameter d1 of the belt cord 7a is more preferably 0.38 mm or less, and even more preferably 0.35 mm or less.

[0056] Preferably, 50 to 200 belt cords 7a are arranged per 5 cm of ply width of the belt plies 7A and 7B. Here, the number n1 of arranged belt cords 7a per 5 cm of ply width is the number of belt cords 7a arranged per 5 cm of ply width in a direction perpendicular to the longitudinal direction of the belt cords 7a. Note that the number n1 of arranged belt cords 7a can be determined, for example, from measurements of the belt plies 7A and 7B in an area including the tire equator C.

[0057] By setting the number n1 of the belt cords 7a arranged per 5 cm of ply width to 50 or more, it is possible to increase the axial rigidity of the tread portion 2 and improve the durability performance of the tire 1 during high-speed running. From this perspective, the number n1 of the belt cords 7a arranged is more preferably 60 or more, and even more preferably 70 or more.

[0058] By setting the number n1 of the belt cords 7a arranged per 5 cm of the ply width to 200 or less, it is possible to prevent the rigidity of the tread portion 2 from becoming excessively high, and to improve the ride comfort performance of the tire 1 during high-speed running. From this perspective, the number n1 of the belt cords 7a arranged is more preferably 190 or less, and even more preferably 180 or less.

[0059] Such belt plies 7A, 7B have a high density of the belt cords 7a in the tire axial direction, and therefore can enhance the restraint of the tread portion 2, thereby improving the durability of the tire 1 during high-speed running.

[0060] In the belt plies 7A and 7B, the product (d1×n1) of the diameter d1 (mm) of the belt cord 7a in the tire radial direction and the number n1 (pieces) of the belt cord 7a arranged per 5 cm of ply width is preferably 35-60.

[0061] If the product (d1×n1) is 35 or more, it is possible to improve the restraining ability of the tread portion 2 and improve the durability performance of the tire 1 during high-speed running. From this viewpoint, the product (d1×n1) is more preferably 38 or more, and further preferably 40 or more.

[0062] By setting the product (d1×n1) to 60 or less, it is possible to suppress vibrations caused by small intervals between the belt cords 7a, and to achieve both ride comfort and durability performance of the tire 1 during high-speed running. From this perspective, the product (d1×n1) is more preferably 57 or less, and even more preferably 55 or less.

[0063] The band cords 9a of the band ply 9A are formed of, for example, organic fibers. Examples of organic fibers for the band cords 9a include polyamides such as nylon 66 and polyesters such as polyethylene terephthalate (PET). The band cords 9a preferably have a diameter d2 in the tire radial direction a of 0.35 to 0.70 mm. Such band cords 9a can suppress vibrations during high-speed running by improving the restraint of the tread portion 2, thereby enabling the tire 1 to achieve both ride comfort and durability during high-speed running.

[0064] By setting the diameter d2 of the band cord 9a in the tire radial direction a to be 0.35 mm or more, it is possible to reliably improve the restraining ability of the tread portion 2 and improve the durability performance of the tire 1 during high-speed running. From this perspective, the diameter d2 of the band cord 9a is more preferably 0.40 mm or more, and even more preferably 0.43 mm or more.

[0065] By setting the diameter d2 of the band cord 9a in the tire radial direction a to 0.70 mm or less, it is possible to suppress an increase in the thickness of the tread portion 2 and improve the ride comfort performance of the tire 1 during high-speed running. From this viewpoint, the diameter d2 of the band cord 9a is more preferably 0.65 mm or less, and even more preferably 0.60 mm or less.

[0066] The band ply 9A preferably has 35 to 65 band cords 9a arranged per 5 cm of ply width. Here, the number n2 of arranged band cords 9a per 5 cm of ply width is the number arranged per 5 cm of ply width in the direction perpendicular to the longitudinal direction of the band cords 9a.

[0067] By setting the number n2 of arranged band cords 9a per 5 cm of ply width to 35 or more, it is possible to reliably improve the restraining ability of the tread portion 2 and improve the durability performance of the tire 1 during high-speed running. From this perspective, the number n2 of arranged band cords 9a is more preferably 40 or more, and even more preferably 45 or more.

[0068] By setting the number n2 of arranged band cords 9a per 5 cm of ply width to 65 or less, it is possible to prevent the rigidity of the tread portion 2 from becoming excessively high, and to improve the ride comfort performance of the tire 1 during high-speed running. From this perspective, the number n2 of arranged band cords 9a is more preferably 60 or less, and even more preferably 55 or less.

[0069] In the band ply 9A, the product (d2 × n2) of the diameter d2 (mm) of the band cord 9a in the tire radial direction a and the number n2 (pieces) of the band cords 9a arranged per 5 cm of ply width is preferably 15 to 45. Such a product (d2 × n2) is the ratio of the band cords 9a to the width direction of the band ply 9A, and is an index related to the spacing between adjacent band cords 9a.

[0070] When the product (d2×n2) is 15 or more, the restraint of the tread portion 2 can be improved, and the durability of the tire 1 during high-speed running can be improved. From this viewpoint, the product (d2×n2) is more preferably 18 or more, and further preferably 20 or more.

[0071] By setting the product (d2×n2) to 45 or less, it is possible to suppress vibrations caused by small intervals between the band cords 9a, and to achieve both ride comfort and durability performance of the tire 1 during high-speed running. From this perspective, the product (d2×n2) is more preferably 42 or less, and even more preferably 40 or less.

[0072] The band cord 9a preferably has a stress of 0.16 to 0.21 N / tex at 3% elongation. When the stress of the band cord 9a at 3% elongation is 0.16 N / tex or more, the restraint of the tread portion 2 is improved, and the durability performance of the tire 1 during high-speed running can be improved. When the stress of the band cord 9a at 3% elongation is 0.21 N / tex or less, the rigidity of the tread portion 2 is prevented from becoming excessively high, and the ride comfort performance of the tire 1 during high-speed running can be improved.

[0073] The band cord 9a preferably has a heat shrinkage stress of 0.01 N / tex or more at 180° C. When the band cord 9a has a heat shrinkage stress of 0.01 N / tex or more, the force tightening the belt cord 7a can be increased, and the tire 1 can achieve both durability and noise performance during high-speed running.

[0074] Here, the thermal shrinkage stress of the band cord 9a is a value measured based on the test method of ASTM D5591, in which the band cord 9a to be measured is fixed at a length of 25 cm with an initial load of 20 g / cord, and then measured at a temperature of 180°C for 2 minutes.

[0075] Although particularly preferred embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above-described embodiments and can be modified and implemented in various forms. [Example]

[0076] A tire having the basic structure shown in Figure 1 was prototyped based on the specifications in Tables 1 and 2. The prototype tire was used to test ride comfort and durability performance during high-speed driving. The common specifications and test methods are as follows:

[0077] <Common specifications> Tire size: 205 / 55R16 Air pressure: 220kPa Band cord composition: A Nylon 66 1400dtex / 2 B PET 1100dtex / 2

[0078] <Ride comfort at high speeds> The prototype tires were mounted on all wheels of a front-wheel drive medium-sized passenger vehicle test vehicle, and the vehicle was driven at 100 km / h on a test course that included straight driving, cornering, and meandering turns. The test driver's sensory evaluation of ride comfort was performed on a scale of 1 to 5. Similar tests were conducted by 20 test drivers, and the total score was calculated. The results were expressed as an index, with the total score for Comparative Example 1 being 100, and a higher index value indicates better ride comfort during high-speed driving.

[0079] <Durability at high speeds> The prototype tire was mounted on a drum testing machine and, under a vertical load of 5.88 N, the speed was increased in steps of 10 km / h from 180 km / h to measure the time until the tire was damaged. The results were expressed as an index, with Comparative Example 1 being set at 100, and the higher the index, the longer the time until damage occurred, indicating superior durability performance at high speeds.

[0080] The test results are shown in Tables 1 and 2. [Table 1]

[0081] [Table 2]

[0082] As a result of the test, the tires of the examples were superior to the comparative examples in terms of ride comfort and durability when traveling at high speeds, and the overall performance, which is determined by the sum of the individual performance values, was also good, confirming that it was possible to achieve both ride comfort and durability when traveling at high speeds.

[0083] [Note] The present disclosure includes the following aspects.

[0084] [Disclosure 1] A tire having a belt layer and a band layer, wherein the belt layer includes at least one belt ply, the belt ply including a belt cord made of a steel solid wire, the band layer including at least one band ply, the band ply including a band cord arranged at an angle of 5° or less with respect to the tire circumferential direction, a gauge which is the distance in the tire radial direction between a surface of the belt cord of the belt ply and a surface of the band cord of the band ply which are adjacent in the tire radial direction is 0.1 to 0.3 mm, and a value obtained by dividing the sum of the diameter (mm) of the belt cord in the tire radial direction and the diameter (mm) of the band cord in the tire radial direction by the gauge (mm) is 4.0 to 13.0.

[0085] [Disclosure 2] The tire according to Disclosure 1, wherein 50 to 200 of the belt cords are arranged per 5 cm of ply width of the belt ply.

[0086] [Disclosure 3] The tire according to Disclosure 1 or 2, wherein the diameter of the belt cord in the tire radial direction is 0.16 to 0.42 mm.

[0087] [Disclosure 4] The tire according to any one of Disclosures 1 to 3, wherein the product of the diameter (mm) of the belt cord in the tire radial direction and the number (number) of the belt cords arranged per 5 cm of ply width in the belt ply is 35 to 60.

[0088] [Disclosure 5] The tire according to any one of Disclosures 1 to 4, wherein 35 to 65 of the band cords are arranged per 5 cm of ply width of the band ply.

[0089] [Disclosure 6] The tire according to any one of Disclosures 1 to 5, wherein the diameter of the band cord in the tire radial direction is 0.35 to 0.70 mm.

[0090] [Disclosure 7] The tire according to any one of Disclosures 1 to 6, wherein in the band ply, the product of the diameter (mm) of the band cord in the tire radial direction and the number (pieces) of the band cords arranged per 5 cm of ply width is 15 to 45.

[0091] [Disclosure 8] The tire according to any one of Disclosures 1 to 7, wherein the band cord has a stress of 0.16 to 0.21 N / tex at 3% elongation.

[0092] [Disclosure 9] The tire according to any one of Disclosures 1 to 8, wherein the band cord has a heat shrinkage stress at 180°C of 0.01 N / tex or more. [Explanation of symbols]

[0093] 1 tire 7 Belt Layer 7B belt ply 7a Belt cord 9 Band Layer 9A Band Ply 9a Band Cord

Claims

1. A tire having a belt layer and a band layer, The belt layer includes at least one belt ply, The belt ply includes a belt cord made of a steel single wire, The band layer includes at least one band ply, the band ply includes a band cord formed of organic fibers and arranged at an angle of 5° or less with respect to the tire circumferential direction, The band cord has a flat cross section, a gauge, which is a distance in the tire radial direction between a surface of the belt cord of the belt ply and a surface of the band cord of the band ply, which are adjacent in the tire radial direction, is 0.1 to 0.3 mm; a value obtained by dividing the sum of the diameter (mm) of the belt cord in the tire radial direction and the diameter (mm) of the band cord in the tire radial direction by the gauge (mm) is 4.0 to 13.0; tire.

2. The tire according to claim 1, wherein the belt cords are arranged in an amount of 50 to 200 per 5 cm of ply width of the belt ply.

3. 3. The tire according to claim 1, wherein the diameter of the belt cord in the tire radial direction is 0.16 to 0.42 mm.

4. 4. The tire according to claim 1, wherein in the belt ply, a product of a diameter (mm) of the belt cord in the tire radial direction and an arrangement number (number) of the belt cord per 5 cm of ply width is 35 to 60.

5. 5. The tire according to claim 1, wherein the band cords are arranged in an amount of 35 to 65 pieces per 5 cm of ply width of the band ply.

6. 6. The tire according to claim 1, wherein the diameter of the band cord in the tire radial direction is 0.35 to 0.70 mm.

7. 7. The tire according to claim 1, wherein in the band ply, a product of a diameter (mm) of the band cord in the tire radial direction and a number (number) of the band cords arranged per 5 cm of a ply width is 15 to 45.

8. 8. The tire according to claim 1, wherein the band cord has a stress of 0.16 to 0.21 N / tex at 3% elongation.

9. The tire according to any one of claims 1 to 8, wherein the band cord has a heat shrinkage stress at 180°C of 0.01 N / tex or more.

10. The tire according to any one of claims 1 to 9, wherein the band cord having a flat cross section is disposed at an angle relative to the tire radial direction.

11. The belt cord has a flat cross section, The tire according to any one of claims 1 to 10, wherein the belt cords having a flat cross section are arranged at an angle relative to the tire radial direction.

12. The tire includes a tread portion extending annularly, a pair of sidewall portions extending on both sides of the tread portion, and a pair of bead portions extending continuously to the sidewall portions, a toroidal carcass extending across the bead cores of the pair of bead portions; The carcass includes at least one carcass ply, the carcass ply includes a main body portion extending from the tread portion through the sidewall portion to the bead core of the bead portion, and a turn-up portion continuing to the main body portion and turned up around the bead core from the inner side to the outer side in the tire axial direction, The tire according to claim 1 , wherein an outer end of the turned-up portion in the tire radial direction extends to the belt layer.

13. The tire includes a tread portion extending annularly, a pair of sidewall portions extending on both sides of the tread portion, and a pair of bead portions extending continuously to the sidewall portions, a toroidal carcass extending across the bead cores of the pair of bead portions; The carcass includes at least one carcass ply, the carcass ply includes a main body portion extending from the tread portion through the sidewall portion to the bead core of the bead portion, and a turn-up portion continuing to the main body portion and turned up around the bead core from the inner side to the outer side in the tire axial direction, The tire according to claim 1 , wherein the bead portion includes a bead reinforcing layer provided axially outward of the turned-up portion.

14. The tire includes a tread portion extending annularly, a pair of sidewall portions extending on both sides of the tread portion, and a pair of bead portions extending continuously to the sidewall portions, a toroidal carcass extending across the bead cores of the pair of bead portions; The carcass includes at least one carcass ply, the carcass ply includes a main body portion extending from the tread portion through the sidewall portion to the bead core of the bead portion, and a turn-up portion continuing to the main body portion and turned up around the bead core from the inner side to the outer side in the tire axial direction, The tire according to claim 1 , wherein the bead portion includes a chafer provided axially outward of the turned-up portion.

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