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JP-2026075509-A - pneumatic tires

JP2026075509AJP 2026075509 AJP2026075509 AJP 2026075509AJP-2026075509-A

Abstract

[Problem] To provide a pneumatic tire that can improve performance on ice. [Solution] A pneumatic tire 1 is provided with a tread portion 2. The outer surface 2s of the tread portion 2 has a pattern portion Pt in which a plurality of blocks B are formed. A belt layer 7 is embedded inside the tread portion 2, including a plurality of belt plies 7s that are stacked in the radial direction of the tire. The plurality of belt plies 7s include a pair of first belt plies 7A spaced apart in the axial direction of the tire, at the innermost part in the radial direction of the tire. The inner ends 7i of each of the pair of first belt plies 7A in the axial direction of the tire are located outside the tire equator C in the axial direction of the tire. A rubber layer 8 is provided in the hollow portion d between the inner ends 7i of the pair of first belt plies 7A in the axial direction of the tire. [Selection Diagram] Figure 1

Inventors

  • 前田 拓郎

Assignees

  • 住友ゴム工業株式会社

Dates

Publication Date
20260508
Application Date
20241022

Claims (14)

  1. A pneumatic tire having a tread section, The outer surface of the tread portion has a pattern portion in which a plurality of blocks are formed by at least three circumferential grooves extending in the tire circumferential direction and a plurality of transverse grooves extending in the tire axial direction. A belt layer extending in the axial direction of the tire is embedded inside the tread portion. The belt layer includes multiple belt plies stacked in the radial direction of the tire, The aforementioned plurality of belt plies include a pair of first belt plies spaced apart in the tire axial direction, located on the innermost side in the tire radial direction. The inner ends of each of the pair of first belt plies in the tire axial direction are located outside the tire axial direction relative to the tire equator. A rubber layer is provided in the hollow portion between the inner ends of the pair of first belt plies in the tire axial direction. Pneumatic tires.
  2. The pneumatic tire according to claim 1, wherein the land ratio of the pattern portion located on the radially outer side of the hollowed-out portion of the tire is 45% to 70%.
  3. The pneumatic tire according to claim 1, wherein the length of the cutout portion in the tire axial direction is 25 to 40% of the length in the tire axial direction between the outer ends of each of the pair of first belt plies in the tire axial direction.
  4. The first belt ply includes a plurality of belt cords and a topping rubber covering the plurality of belt cords. The pneumatic tire according to any one of claims 1 to 3, wherein the rubber layer is formed of the same rubber material as the topping rubber.
  5. The pneumatic tire according to any one of claims 1 to 3, wherein the land ratio of the pattern portion located on the radially outer side of the first belt ply is greater than the land ratio of the pattern portion located on the radially outer side of the hollow portion.
  6. The pneumatic tire according to any one of claims 1 to 3, wherein the plurality of blocks are provided with a plurality of sipes extending in the tire axial direction and dividing the blocks into two or more block pieces.
  7. The pneumatic tire according to claim 6, wherein the depth of the plurality of sipes overlapping the hollowed-out portion in the tire axial direction is 40% to 65% of the groove depth of the circumferential groove defining the block overlapping the hollowed-out portion in the tire axial direction.
  8. The pneumatic tire according to claim 6, wherein the plurality of sipes overlapping the hollow portion and the tire axial direction include a flask sipe comprising a sipe body extending inward in the tire radial direction from the outer surface of the tread portion, and a widening portion connected to the sipe body radially inward and having a wider width than the sipe body.
  9. The pneumatic tire according to any one of claims 1 to 3, wherein the groove depth of the plurality of lateral grooves overlapping the hollowed-out portion in the tire axial direction is 60% to 80% of the groove depth of the circumferential groove defining the block overlapping the hollowed-out portion in the tire axial direction.
  10. The tread portion includes a cap rubber that forms the outer surface, The pneumatic tire according to any one of claims 1 to 3, wherein the rubber hardness of the cap rubber is 60 to 65.
  11. The aforementioned multiple belt plies include the outermost cover plies in the tire radial direction, The pneumatic tire according to any one of claims 1 to 3, wherein the length of the cover ply in the tire axial direction is greater than the length of the cutout portion in the tire axial direction.
  12. The aforementioned circumferential grooves include a pair of crown circumferential grooves adjacent to each other on either side of the tire equator. The block includes a crown block defined by the pair of crown circumferential grooves, The pneumatic tire according to claim 1, wherein the crown block is located radially outward of the hollowed-out portion of the tire.
  13. The aforementioned circumferential groove includes a crown circumferential groove that passes along the tire equator. The tread portion includes a pair of crown longitudinal grooves that are adjacent to both sides of the crown circumferential groove in the tire axial direction and extend in the tire circumferential direction with a groove width smaller than the groove width of the crown circumferential groove, The block includes a crown block defined by the crown circumferential groove and each of the pair of crown longitudinal grooves, The pneumatic tire according to claim 1, wherein the crown block is located radially outward of the hollowed-out portion of the tire.
  14. The aforementioned hollow portion overlaps with the crown block in the tire axial direction, as described in claim 12 or 13, for a pneumatic tire.

Description

This invention relates to a pneumatic tire. Patent Document 1 below describes a pneumatic tire equipped with shoulder blocks. The shoulder blocks include a second shoulder block separated on the outer side of the shoulder sub-groove in the tire axial direction. The second shoulder block is divided into a first block piece and a second block piece by a split sipe crossing the block. The first and second block pieces are provided with a second open sipe communicating with the shoulder sub-groove. Such a pneumatic tire is said to exhibit excellent ice performance. Japanese Patent Publication No. 2017-121936 This is a meridian cross-sectional view of a pneumatic tire according to one embodiment of the present invention.Figure 1 is an unfolded view of the tire's belt layer and carcass.Figure 1 is an exploded view of the tire tread.This is an enlarged view of the space between the pair of crown circumferential grooves shown in Figure 3.This is an enlarged view of the space between the crown circumferential groove and the shoulder circumferential groove in Figure 3.Figure 3 is an enlarged view of the area between the shoulder circumferential groove and the tread edge.Figure 1 is an exploded view of the tire tread.(A) is a cross-sectional view taken along line A-A in Figure 7, and (B) is a cross-sectional view taken along line B-B in Figure 7.Figure 1 is a meridian cross-section of the tire.This is a cross-sectional view of a sipe in another embodiment.This is a meridian cross-sectional view of a pneumatic tire of another embodiment.Figure 11 is an exploded view of the tire tread. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The drawings contain exaggerations and representations that differ from the actual structural dimensional ratios, in order to aid in understanding the present invention. Furthermore, where there are multiple embodiments, the same or common elements are denoted by the same reference numerals throughout the specification, and redundant descriptions are omitted. Figure 1 is a meridian cross-sectional view of a pneumatic tire (hereinafter sometimes referred to as "tire") 1, illustrating one embodiment of the present invention. Figure 1 shows the tread portion 2 of the tire 1. Figure 1 also shows a preferred embodiment of a tire for a truck and a bus. However, the present invention may also be applied to tires for passenger cars and light trucks. Figure 1 shows a tire 1 in its normal state. The aforementioned "normal state" refers to the unloaded state in the case of pneumatic tires for which various standards are defined, where the tire is mounted on a standard rim (not shown) and adjusted to the standard internal pressure. For tires for which various standards are not defined, the "normal state" refers to the standard operating state according to the tire's intended use, meaning the tire is not mounted on a vehicle and is unloaded. In this specification, unless otherwise specified, the dimensions of each part of the tire are values measured in the "normal state." Furthermore, for components that cannot be measured in the "normal state" (for example, the internal materials of the tire), the values are measured with the tire in a state as close as possible to the "normal state." A "standard rim" is the rim specified for each tire within the tire's standardization system, including the standard on which the tire is based. For example, it would be a "standard rim" for JATMA, a "design rim" for TRA, or a "measuring rim" for ETRTO. "Regular internal pressure" refers to the air pressure specified for each tire within the tire standard system, including the standard on which the tire is based. For example, it's the "maximum air pressure" for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUSCOLD INFLATION PRESSURES" for TRA, and "INFLATION PRESSURE" for ETRTO. The outer surface 2s of the tread portion 2 has a pattern portion Pt in which multiple blocks B are formed by at least three circumferential grooves 3 extending in the tire circumferential direction and a plurality of transverse grooves 4 extending in the tire axial direction. In this specification, "extending in the tire axial direction" includes grooves that extend at an inclination with respect to the tire axial direction, for example, grooves with an angle α1 (shown in Figure 3) of 45 degrees or less with respect to the tire axial direction. The circumferential grooves 3 extend continuously in the tire circumferential direction. A belt layer 7 extending in the tire axial direction is embedded within the tread portion 2. The belt layer 7 includes multiple belt plies 7s stacked in the tire radial direction. The multiple belt plies 7s include a pair of first belt plies 7A spaced apart in the tire axial direction, located at the innermost point in the tire radial direction. The inner ends 7i of each pair of first belt plies 7A in the tire axial direction are located out