tire

Abstract

To provide a tire capable of achieving both ride comfort performance and durability performance during high-speed traveling.SOLUTION: Provided is a tire 1 having a belt layer 7 and a band layer 9. The belt layer 7 includes at least one belt ply 7A. The belt ply 7A includes belt cords 7a formed of 60 to 140 aligned steel single wires per 5 cm ply width. The band layer 9 includes at least one band ply 9A. The band ply 9A includes band cords 9a disposed at an angle of 5° or less with respect to a tire circumferential direction. The band cords 9a have flat cross sections orthogonal to the longitudinal direction of the band cords 9a.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a tire having a belt layer, a band, and the like. [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 the gauge between the cords of two adjacent layers is specified, thereby achieving 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 invention 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 and durability when traveling at high speeds. [Means for solving the problem]

[0006] The present invention is a tire having a belt layer and a band layer, wherein the belt layer includes at least one belt ply, and the belt ply includes belt cords made of steel single wires arranged in an array of 60 to 140 pieces per 5 cm of ply width, and the band layer includes at least one band ply, and the band ply includes band cords arranged at an angle of 5° or less with respect to the tire circumferential direction, and the band cord has a flat cross section perpendicular to the longitudinal direction of the band cord.

[0007] In the tire of the present invention, the aspect ratio of the band cord is preferably 1.05 to 1.25.

[0008] In the tire of the present invention, the band cord is preferably formed from a heat-shrinkable organic fiber.

[0009] In the tire of the present invention, the organic fiber is preferably nylon.

[0010] In the tire of the present invention, it is desirable that the belt ply and the band ply satisfy the following formula (1).

number

[0011] In the tire of the present invention, the belt ply preferably has a product of the strength (N) of each belt cord and the number (pieces) of the belt cords arranged per 5 cm of ply width of 12,000 to 22,000 (N·pieces).

[0012] In the tire of the present invention, it is preferable that the belt cord has a ternary plating layer made of copper (Cu), zinc (Zn) and cobalt (Co) formed on the surface thereof.

[0013] In the tire of the present invention, the mass ratio of the composition of the ternary plating layer is preferably less than 65% of copper (Cu), less than 35% of zinc (Zn), and less than 10% of cobalt (Co). [Effects of the Invention]

[0014] The tire of the present invention has a belt layer and a band layer, the belt layer including at least one belt ply, the belt ply including belt cords made of steel single wires arranged in an array of 60 to 140 pieces per 5 cm of ply width, the band layer including at least one band ply, the band ply including band cords arranged at an angle of 5° or less with respect to the tire circumferential direction, and the band cords having a flat cross section perpendicular to the longitudinal direction of the band cords.

[0015] In such a tire, the belt cords are arranged at a high density, which provides high restraining force and suppresses the growth of the outer diameter of the tread portion during high-speed running, thereby improving durability during high-speed running. Furthermore, since the band cords in this tire are flat, the thickness of the rubber between the belt cords can be increased, which suppresses excessive increase in the rigidity of the tread portion due to the high-density belt cords, thereby improving ride comfort during high-speed running. Therefore, the tire of the present invention can achieve both ride comfort and durability during high-speed running. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing one embodiment of a tire of the present invention. [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. 2 is a schematic diagram of a belt cord. [Figure 4]FIG. 2 is a schematic diagram of a band cord. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention 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.

[0018] 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.

[0019] "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, "normal internal pressure" is the air pressure set for each tire by the manufacturer, etc.

[0020] 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.

[0021] Although there are no particular limitations on the type of passenger car tire as long as the normal load is 1000 kg or less, the normal load is preferably 900 kg, more preferably 750 kg, and even more preferably 700 kg, from the viewpoint of suppressing excessive deformation in the tread portion 2. The normal internal pressure is 250 kPa for passenger car tires.

[0022] "Normal load" is the load determined for each tire by the standard system including the standard on which tire 1 is based, and is the "maximum load capacity" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "LOAD CAPACITY" for ETRTO. "Normal load" is the load determined for each tire by the manufacturer, etc., when there is no standard system including the standard on which tire 1 is based.

[0023] 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 below can be applied to various tires, such as a resin tire using a thermoplastic elastomer and a non-pneumatic tire that is not filled with pressurized air inside.

[0024] 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.

[0025] The tread portion 2 is desirably formed of at least one elastomer layer. The tread portion 2 may, for example, have two or more elastomer layers laminated in the tire radial direction a, or may have multiple elastomer layers in the tire axial direction. 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. The profile of the outer surface 2a of the tread portion 2 is, for example, a single arc or a combination of arcs with multiple curvatures.

[0026] Examples of the elastomer layer of the tread portion 2 include natural rubber, isoprene-based rubber such as isoprene rubber, butadiene rubber, styrene butadiene rubber, styrene isoprene butadiene rubber, chloroprene rubber, acrylonitrile butadiene rubber, and diene-based rubber such as butyl rubber.

[0027] The sidewall portion 3 is desirably formed of 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.

[0028] 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.

[0029] 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."

[0030] 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 tire axial direction. The outer end of the turned-up portion 6b in the tire radial direction a may extend to the belt layer 7. Between the main body portion 6a and the turned-up portion 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.

[0031] The bead portion 4 may be provided with a bead reinforcing layer (not shown), for example, on the axially outer side of the turned-up portion 6b of the carcass 6. The bead reinforcing layer may be formed of an elastomer layer having the same components as the bead apex 8, or may be formed of an elastomer layer having a different component.

[0032] The bead portion 4 may be provided with a chafer (not shown), for example, on the axially outer side 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 outer than the bead reinforcing layer.

[0033] 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 outer side in the tire radial direction and a second belt ply 7B located on the inner side of the first belt ply 7A. Such a belt layer 7 can increase the binding force and improve the durability performance of the tire 1 when traveling at high speeds.

[0034] In this embodiment, a band layer 9 is arranged on the inner side of the tread portion 2 in the tire radial direction a and on the outer side of the belt layer 7 in the tire radial direction a. The band layer 9 includes at least one band ply 9A, in this embodiment one band ply 9A. Such a band layer 9 can increase the restraint of the tread portion 2 even during high-speed running, and further improve the durability performance of the tire 1.

[0035] 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 is suitable for maintaining the air pressure filled in the tire 1.

[0036] Fig. 2 is a cross-sectional view of the belt layer 7 and the band layer 9 of this embodiment. As shown in Fig. 2, 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. Such belt plies 7A and 7B are less likely to stretch than the stranded cords, and can increase the binding force, thereby improving the durability of the tire 1 during high-speed running.

[0037] 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.

[0038] The belt cord 7a of the present embodiment is plated or ternary plated. Examples of plating include zinc, copper, and the like. A ternary plating layer made of copper (Cu), zinc (Zn), and cobalt (Co) is preferably formed on the surface of the belt cord 7a. The mass ratio of the composition of the ternary plating layer is preferably less than 65% copper (Cu), less than 35% zinc (Zn), and less than 10% cobalt (Co). Such a belt cord 7a has good adhesion to the elastomer composition 7G, and the belt cord 7a and the elastomer composition 7G can generate a cooperative stress even during high-speed running, thereby improving the durability of the tire 1 during high-speed running.

[0039] The belt cord 7a of this embodiment has a flat cross section perpendicular to the longitudinal direction of the belt cord 7a. In this specification, "flat" means that the aspect ratio of the major axis to the minor axis of the cross section is 1.05 or more. The belt cord 7a may have a circular cross section, for example. In this specification, "circular" means that the aspect ratio of the cross section is less than 1.05.

[0040] 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 in opposite directions with respect to the tire circumferential direction. Such a belt layer 7 can enhance the binding force of the tread portion 2 in a balanced manner and improve the durability performance of the tire 1 during high-speed running. 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.

[0041] The belt plies 7A, 7B preferably have 60 to 140 belt cords 7a arranged per 5 cm of ply width. 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. The number n1 of arranged belt cords 7a can be determined, for example, from measurements of the belt plies 7A, 7B in an area including the tire equator C.

[0042] By setting the number n1 of the belt cords 7a arranged per 5 cm of the ply width to 60 or more, it is possible to increase the binding force 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 70 or more, and even more preferably 80 or more.

[0043] By setting the number n1 of the belt cords 7a arranged per 5 cm of the ply width to 140 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 130 or less, and even more preferably 120 or less.

[0044] Such a tire 1 has belt cords 7a arranged at a high density, which provides a high restraining force and can suppress the growth of the outer diameter of the tread portion 2 during high-speed driving, thereby improving durability during high-speed driving.

[0045] The belt cord 7a preferably has a diameter d1 in the tire radial direction a of 0.2 mm or less. Since the diameter d1 in the tire radial direction a of the belt cord 7a is small, the rigidity in the tire radial direction a can be reduced, and the ride comfort performance of the tire 1 during high-speed running can be improved.

[0046] From this perspective, the diameter d1 of the belt cord 7a in the tire radial direction a is more preferably 0.17 mm or less. The lower limit of the diameter d1 of the belt cord 7a is not particularly limited, but is preferably 0.1 mm or more, and more preferably 0.12 mm or more. Here, the diameter d1 of the belt cord 7a in the tire radial direction a is the diameter along the tire radial direction a.

[0047] Fig. 3 is a schematic diagram of a belt cord 7a. As shown in Fig. 3, 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 defined as the diameter d1 in the tire radial direction a. In Fig. 3, the angle θ1 in the direction of the minor axis Sd with respect to the tire radial direction a is smaller than the angle θ2 in the direction of the major axis Ld, so the minor axis Sd is defined as the diameter d1 in the tire radial direction a.

[0048] 2, in the belt plies 7A, 7B, the product (d1 × n1) of the diameter d1 (mm) of the belt cord 7a and the number n1 (pieces) of the belt cord 7a arranged per 5 cm of ply width is preferably 25 (mm × pieces). Such a product (d1 × n1) is the ratio of the belt cord 7a to the width of the belt plies 7A, 7B, and is an index related to the spacing between adjacent belt cords 7a in the width direction.

[0049] By setting the product (d1×n1) to 25 (mm·pieces), it is possible to prevent the rigidity of the tread portion 2 from becoming excessively high, and improve the ride comfort performance of the tire 1 during high-speed driving. From this perspective, the product (d1×n1) is more preferably 23 (mm·pieces) or less, and even more preferably 20 (mm·pieces) or less.

[0050] In the belt plies 7A and 7B, the product (d1×n1) of the diameter d1 (mm) of the belt cord 7a and the number n1 (pieces) of the belt cord 7a arranged per 5 cm of ply width is preferably 10 (mm·pieces) or more. When the product (d1×n1) is 10 (mm·pieces) or more, the restraint of the tread portion 2 can be improved, and the durability performance of the tire 1 during high-speed running can be improved. From this viewpoint, the product (d1×n1) is more preferably 12 (mm·pieces) or more, and even more preferably 15 (mm·pieces) or more.

[0051] In the belt plies 7A and 7B, the product (s1 × n1) of the strength s1 (N) per belt cord 7a and the number n1 (pieces) of belt cords 7a arranged per 5 cm of ply width is preferably 12,000 to 22,000 (N·pieces). Here, the strength s1 (N) per belt cord 7a is the tension of one belt cord 7a at 25°C at break.

[0052] By setting the product (s1×n1) to 12,000 (N·pieces) 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 (s1×n1) is more preferably 13,500 (N·pieces) or more, and even more preferably 15,000 (N·pieces) or more.

[0053] By setting the product (s1×n1) to 22,000 (N·pieces) or less, it is possible to prevent the rigidity of the tread portion 2 from becoming excessively high, and improve the ride comfort performance of the tire 1 during high-speed driving. From this perspective, the product (s1×n1) is more preferably 21,000 (N·pieces) or less, and even more preferably 20,000 (N·pieces) or less.

[0054] 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 covering the band cords 9a. 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.

[0055] The band cord 9a of this embodiment has a flat cross section perpendicular to the longitudinal direction of the band cord 9a. In this tire 1, the thickness of the rubber between the belt cord 7a and the band cord 9a can be increased, and the high-density belt cord 7a prevents the rigidity of the tread portion 2 from becoming excessively high, thereby improving ride comfort during high-speed driving. Therefore, the tire 1 of this embodiment can achieve both ride comfort and durability during high-speed driving.

[0056] In a more preferred embodiment, the aspect ratio of the band cord 9a is 1.05 to 1.25. When the aspect ratio of the band cord 9a is 1.05 or more, the thickness of the rubber between the belt cord 7a and the band cord 9a can be reliably increased, and the ride comfort performance of the tire 1 during high-speed running can be improved. From this perspective, the aspect ratio of the band cord 9a is more preferably 1.08 or more, and even more preferably 1.10 or more.

[0057] By setting the aspect ratio of the band cord 9a to 1.25 or less, it is possible to suppress excessive change in rigidity between the tire axial direction and the tire radial direction a of the tread portion 2, thereby improving the durability performance of the tire 1 during high-speed running. From this viewpoint, the aspect ratio of the band cord 9a is more preferably 1.22 or less, and even more preferably 1.20 or less.

[0058] The band cord 9a is made of, for example, organic fiber. The band cord 9a of this embodiment is made of heat-shrinkable organic fiber. Such band cord 9a can increase the binding force of the tread portion 2 by generating heat during high-speed running, thereby further improving the durability performance of the tire 1 during high-speed running.

[0059] Examples of heat-shrinkable organic fibers include aliphatic polyamide (nylon), polyethylene, and polyester. The organic fiber in this embodiment is nylon. Nylon has excellent strength and heat-shrinkability, and is suitable for improving the durability of the tire 1 during high-speed running.

[0060] The band cord 9a preferably has a diameter d2 in the tire radial direction a of 0.40 to 0.70 mm. Here, the diameter d2 of the band cord 9a in the tire radial direction a is the diameter along the tire radial direction a.

[0061] By setting the diameter d2 of the band cord 9a in the tire radial direction a to be 0.40 mm or more, the restraint performance of the tread portion 2 can be reliably improved, and the ride comfort performance and durability performance of the tire 1 during high-speed running can be compatible. From this perspective, the diameter d2 of the band cord 9a is more preferably 0.50 mm or more, and even more preferably 0.55 mm or more.

[0062] 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.

[0063] Fig. 4 is a schematic diagram of a band cord 9a. As shown in Fig. 4, when the band cord 9a 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 band cord 9a with a flat cross section, the one with a smaller angle with respect to the tire radial direction a is set to the diameter d2 in the tire radial direction a. In Fig. 4, the angle θ3 of the minor axis Sd with respect to the tire radial direction a is smaller than the angle θ4 of the major axis Ld, so the minor axis Sd is set to the diameter d2 in the tire radial direction a.

[0064] 2, 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] By making the product (d2×n2) 15 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 4. From this viewpoint, the product (d2×n2) is more preferably 20 or more.

[0069] When the product (d2×n2) is 45 or less, it is possible to suppress peeling caused by small intervals between the band cords 9a and improve the durability performance of the tire 1. From this viewpoint, the product (d2×n2) is more preferably 40 or less.

[0070] It is desirable that the belt ply 7A and the band ply 9A satisfy the following formula (1).

number

[0071] Such belt ply 7A and band ply 9A can appropriately maintain the thickness of the rubber between the belt cord 7a and band cord 9a adjacent in the tire radial direction a, and can achieve both ride comfort performance and durability performance of the tire 1 when traveling at high speeds.

[0072] Here, the thickness G1 of the belt ply 7A is the maximum thickness of the elastomer composition 7G of the belt ply 7A in the tire radial direction a. The thickness G2 of the band ply 9A is the maximum thickness of the elastomer composition 9G of the band ply 9A in the tire radial direction a. The thickness G1 of the belt ply 7A and the thickness G2 of the band ply 9A can be confirmed, for example, from a cross section of the tread portion 2. Note that if the boundary of the belt ply 7A is unclear in the cross section of the tread portion 2, the boundaries of the belt ply 7A may be understood as, for example, the midpoints of the belt cords 7a adjacent to each other in the tire radial direction a, and the midpoints between the belt cords 7a and the band cords 9a.

[0073] Although a particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment and can be modified and practiced in various ways. [Example]

[0074] 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:

[0075] <Common specifications> Tire size: 195 / 65R15 Rim size: 15x6JJ Belt cord: Steel solid wire

[0076] <Ride comfort at high speeds> Using a test vehicle, a front-wheel drive medium-sized passenger car fitted with prototype tires with an air pressure adjusted to 230 kPa on all wheels, the test vehicle was driven on a test course at a speed of 100 km / h, and the ride comfort performance was evaluated by the test driver 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 the higher the index value, the better the ride comfort performance at high speeds.

[0077] <Durability at high speeds> After thermal degradation of prototype tires with an air pressure adjusted to 150 kPa in an 80°C environment for 168 hours, they were mounted on a drum testing machine and driven at a speed of 80 km / h under a load of 6.96 kN, and the distance until air leakage or deformation of the sidewall occurred was measured. The results are expressed as an index, with Comparative Example 1 being set at 100, and the higher the index, the better the durability at high speeds.

[0078] The test results are shown in Tables 1 and 2. [Table 1]

[0079] [Table 2]

[0080] 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. [Explanation of symbols]

[0081] 1 tire 7 Belt Layer 7A 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 belt cords made of steel single wires arranged in an amount of 60 to 140 per 5 cm of ply width, The band layer includes at least one band ply, the band ply includes a band cord formed of a heat-shrinkable organic fiber and arranged at an angle of 5° or less with respect to the tire circumferential direction, the band cord has a flat cross section perpendicular to the longitudinal direction of the band cord, The band cord having a flat cross section is disposed at an angle with respect to the tire radial direction. tire.

2. A tire as described in claim 1, wherein the radial diameter of the belt cord is 0.17 mm or less.

3. A tire as described in claim 1 or 2, wherein the belt ply and the band ply satisfy the following formula (1): [Equation 1] where: G1: Thickness in the tire radial direction of the belt ply in contact with the band ply G2: Thickness in the tire radial direction of the band ply in contact with the belt ply d1: diameter of the belt cord in the tire radial direction d2: diameter of the band cord in the tire radial direction

4. The tire according to any one of claims 1 to 3, wherein the aspect ratio of the band cord is 1.05 to 1.

25.

5. 5. The tire according to claim 1, wherein the organic fiber is nylon.

6. The tire according to any one of claims 1 to 5, wherein the product of the strength (N) per belt cord of the belt ply and the number (pieces) of the belt cords arranged per 5 cm of ply width is 12,000 to 22,000 (N pieces).

7. The tire according to any one of claims 1 to 6, wherein the belt cord has a surface formed with a ternary plating layer made of copper (Cu), zinc (Zn), and cobalt (Co).

8. The tire according to claim 7, wherein the mass ratio of the composition of the ternary plating layer is less than 65% of the copper (Cu), less than 35% of the zinc (Zn), and less than 10% of the cobalt (Co).

9. The belt cord has a flat cross section perpendicular to the longitudinal direction of the belt cord, The tire according to claim 1 , wherein the belt cords having a flat cross section are arranged at an angle relative to the tire radial direction.

10. The tire includes a tread portion extending annularly and a pair of sidewall portions extending on both sides of the tread portion, 10. The tire according to claim 1, wherein an axially outer end side of an interface between the elastomer layer of the tread portion and the elastomer layer of the sidewall portion is positioned radially outward of an inner end side of the interface.

11. The tire includes a tread portion extending annularly and a pair of sidewall portions extending on both sides of the tread portion, 10. The tire according to claim 1, wherein an outer end side of an interface between the elastomer layer of the tread portion and the elastomer layer of the sidewall portion in an axial direction of the tire is located radially inward of an inner end side thereof.

12. a toroidal carcass extending across a pair of bead cores of the bead portions; The carcass includes at least one carcass ply, the carcass ply includes a main body portion extending from a tread portion through a 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. a toroidal carcass extending across a pair of bead cores of the bead portions; The carcass includes at least one carcass ply, the carcass ply includes a main body portion extending from a tread portion through a 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 a bead reinforcing layer is provided in the bead portion axially outside the turned-up portion of the carcass.

14. a toroidal carcass extending across a pair of bead cores of the bead portions; The carcass includes at least one carcass ply, the carcass ply includes a main body portion extending from a tread portion through a 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 is provided with a chafer on an outer side of the turned-up portion of the carcass in the tire axial direction.

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