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US-12623492-B2 - Heavy duty tire

US12623492B2US 12623492 B2US12623492 B2US 12623492B2US-12623492-B2

Abstract

A tire includes a reinforcing layer positioned between a carcass and a tread. The reinforcing layer includes a belt and a band. The belt includes an inner belt ply and an outer belt ply. An inclination direction of the belt cords included in the inner belt ply is opposite to an inclination direction of the belt cords included in the outer belt ply. The band includes a full band obtained by spirally winding a full band strip. The full band is positioned between the inner belt ply and the outer belt ply. The full band strip includes a cord array including a plurality of band cords arrayed. The band cords included in the full band strip are not less than two and not greater than five in number.

Inventors

  • Riho FUJII
  • Kae ITO

Assignees

  • SUMITOMO RUBBER INDUSTRIES, LTD.

Dates

Publication Date
20260512
Application Date
20250514
Priority Date
20240603

Claims (16)

  1. 1 . A heavy duty tire comprising a pair of beads, a carcass extending between the pair of beads, a tread positioned radially outside the carcass and having a tread surface configured to come into contact with a road surface, and a reinforcing layer positioned radially between the carcass and the tread, wherein the reinforcing layer includes a belt including a large number of belt cords arranged parallelly, and a band including a band cord spirally wound, the belt includes an inner belt ply and an outer belt ply aligned radially, an inclination direction of the belt cords included in the inner belt ply is opposite to an inclination direction of the belt cords included in the outer belt ply, the band includes a full band obtained by spirally winding a full band strip, the full band is positioned between the inner belt ply and the outer belt ply, the full band strip includes a cord array in which a plurality of the band cords are arranged, the band cords included in the full band strip are not less than two and not greater than five in number, a ratio of an axial width of the full band to a width of the tread surface is not less than 0.70 and not greater than 0.80, and in the full band strip, the band cords are adjacent to each other at an interval not less than 0.5 mm and not greater than 2.0 mm.
  2. 2 . The heavy duty tire according to claim 1 , wherein the outer belt ply has an end positioned axially outside an end of the full band.
  3. 3 . The heavy duty tire according to claim 1 , wherein the band cords included in the full band strip are three in number.
  4. 4 . The heavy duty tire according to claim 1 , wherein at an end of the full band, a distance between the full band and the inner belt ply is not greater than 2.0 mm.
  5. 5 . The heavy duty tire according to claim 1 , wherein at an end of the outer belt ply, a distance between the outer belt ply and the inner belt ply is not less than 3.0 mm.
  6. 6 . The heavy duty tire according to claim 1 , wherein the tread includes a base portion positioned radially outside the reinforcing layer, and a cap portion positioned radially outside the base portion and having the tread surface, and on a normal line of the carcass passing through an end of the tread surface, a ratio of a thickness of the base portion to a thickness of the tire is not greater than 1/3.
  7. 7 . The heavy duty tire according to claim 6 , wherein the ratio of the thickness of the base portion to the thickness of the tire is not greater than 1/5.
  8. 8 . The heavy duty tire according to claim 6 , wherein an end of the reinforcing layer is positioned axially inside the normal line of the carcass.
  9. 9 . The heavy duty tire according to claim 6 , wherein an end of the base portion is positioned axially outside the normal line of the carcass, and an inner end of the cap portion is positioned radially inside an inner end of the base portion.
  10. 10 . The heavy duty tire according to claim 1 , wherein the band further includes a pair of edge bands each obtained by spirally winding an edge band strip, the edge band strip includes a cord array in which a plurality of the band cords are arranged, and the pair of edge bands is positioned radially outside ends of the full band, respectively.
  11. 11 . The heavy duty tire according to claim 10 , wherein in the edge band strip, the band cords are adjacent to each other at an interval not less than 0.5 mm and not greater than 2.0 mm.
  12. 12 . The heavy duty tire according to claim 10 , wherein at an end of the full band, a distance between the edge band and the outer belt ply is not greater than 2.0 mm.
  13. 13 . The heavy duty tire according to claim 10 , wherein the band cords included in the edge band strip are not less than two and not greater than five in number.
  14. 14 . The heavy duty tire according to claim 13 , wherein the band cords included in the edge band strip are three in number.
  15. 15 . The heavy duty tire according to claim 10 , wherein the tread includes a plurality of circumferential grooves continuously extending in the circumferential direction, among the plurality of circumferential grooves, a circumferential groove located axially outermost is a shoulder circumferential groove, the edge band is positioned axially between the shoulder circumferential groove and an end of the belt, a position on the tread surface corresponding to an inner end of the edge band is an inner end corresponding position, and a length from the shoulder circumferential groove to the inner end corresponding position is smaller than a groove width of the shoulder circumferential groove.
  16. 16 . The heavy duty tire according to claim 15 , wherein a ratio of the length from the shoulder circumferential groove to the inner end corresponding position to the groove width of the shoulder circumferential groove is not less than 0.30 and not greater than 0.50.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims priority based on Japanese Patent Application No. 2024-089683 filed on Jun. 3, 2024, and entire contents of this Japanese Patent Application are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to heavy duty tires. BACKGROUND ART A tire in a running state repeats deformation and restoration. A heavy duty tire tends to have outer radial growth. The outer radial growth influences uneven wear resistance and durability. A tire includes a band as one of components thereof. The band includes a band cord extending substantially in a circumferential direction. The band can contribute to suppression of outer radial growth due to running. Adopting such a band has been considered for suppression of outer radial growth and improvements in uneven wear resistance and durability (e.g., Japanese Laid-Open Patent Publication No. 2022-047999 (PATENT LITERATURE 1)). SUMMARY OF THE INVENTION Technical Problem An object of the present disclosure is to provide a heavy duty tire that can be improved in uneven wear resistance and durability. Solution to Problem A heavy duty tire according to an aspect of the present disclosure includes: a pair of beads, a carcass extending between the pair of beads, a tread positioned radially outside the carcass and having a tread surface configured to come into contact with a road surface, and a reinforcing layer positioned radially between the carcass and the tread. The reinforcing layer includes a belt including a large number of belt cords arranged parallelly, and a band including a band cord spirally wound. The belt includes an inner belt ply and an outer belt ply aligned radially. An inclination direction of the belt cords included in the inner belt ply is opposite to an inclination direction of the belt cords included in the outer belt ply The band includes a full band obtained by spirally winding a full band strip. The full band is positioned between the inner belt ply and the outer belt ply. The full band strip includes a cord array in which a plurality of the band cords are arranged. The band cords included in the full band strip are not less than two and not greater than five in number. Advantageous Effects of the Invention The present disclosure can provide a heavy duty tire that can be improved in uneven wear resistance and durability. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a sectional view showing part of a heavy duty tire according to an embodiment of the present disclosure. FIG. 2A is an enlarged sectional view showing part of the tire in FIG. 1. FIG. 2B is an enlarged sectional view showing portion B in FIG. 2A. FIG. 2C is an enlarged sectional view showing portion C in FIG. 2A. FIG. 3 is a sectional view of a circumferential groove. FIG. 4 is an explanatory schematic view of a configuration of a reinforcing layer. FIG. 5 is a perspective view showing part of a full band strip. FIG. 6 is a perspective view showing part of an edge band strip. DETAILED DESCRIPTION Description is made in detail hereinafter to a preferred embodiment of the present disclosure with reference to the drawings as appropriate. A tire according to the present disclosure is fitted on a rim. The inside of the tire is filled with air to adjust the internal pressure of the tire. The tire fitted on the rim is also referred to as tire-rim assembly. The tire-rim assembly includes the rim and the tire fitted on the rim. In the present disclosure, a state where a tire is fitted on a normal rim, the internal pressure of the tire is adjusted to a normal internal pressure, and no load is applied to the tire is referred to as normal state. In the present disclosure, unless otherwise specified, dimensions and angles of each component of the tire are measured in the normal state. The dimensions and angles of each component in a meridian cross-section of the tire, which cannot be measured in a state where the tire is fitted on the normal rim, are measured in a cut plane of the tire obtained by cutting the tire along a plane including a rotation axis. In this measurement, the tire is set such that the distance between right and left beads is equal to the distance between the beads in the tire that is fitted on the normal rim. The configuration of the tire that cannot be checked in a state where the tire is fitted on the normal rim is checked in the cut plane described above. The normal rim means a rim specified in a standard on which the tire is based. The “standard rim” in the JATMA standard, the “design rim” in the TRA standard, and the “measuring rim” in the ETRTO standard are normal rims. The normal internal pressure means an internal pressure specified in the standard on which the tire is based. The “highest air pressure” in the JATMA standard, the “maximum value” recited in the “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” in the TRA standard, and the “inflation pressure” in the ETRTO standard are normal int