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JP-2026076011-A - Heavy-duty tires

JP2026076011AJP 2026076011 AJP2026076011 AJP 2026076011AJP-2026076011-A

Abstract

[Problem] To provide a heavy-duty tire that can suppress the occurrence of block breakage while ensuring heat dissipation and wear resistance. [Solution] The tread surface has one or more zigzag grooves 2 extending in a zigzag pattern in the tire circumferential direction, and a plurality of widthwise grooves 3 extending in the tire width direction. The groove width of the zigzag grooves 2 is 20.0 mm or less, and the groove width of the widthwise grooves is 20.0 mm or less. The zigzag grooves 2 consist of a first portion extending in the tire circumferential direction and a second portion extending at an inclination with respect to the tire circumferential direction. Two adjacent second portions sandwiching the first portion are inclined in opposite directions with respect to the tire circumferential direction, and the second portion is located between two widthwise grooves 3 adjacent in the tire circumferential direction. [Selection Diagram] Figure 1

Inventors

  • 中原 文弥

Assignees

  • 株式会社ブリヂストン

Dates

Publication Date
20260511
Application Date
20241023

Claims (13)

  1. The tread surface has one or more zigzag grooves extending in a zigzag pattern in the circumferential direction of the tire, and multiple widthwise grooves extending in the width direction of the tire. The groove width of the aforementioned zigzag narrow groove is 20.0 mm or less. The groove width of the aforementioned narrow groove in the width direction is 20.0 mm or less. The zigzag groove consists of a first portion extending in the circumferential direction of the tire and a second portion extending at an inclination with respect to the circumferential direction of the tire, wherein two adjacent second portions sandwiching the first portion are inclined in opposite directions with respect to the circumferential direction of the tire. A heavy-duty tire characterized in that the second portion is located between two adjacent narrow grooves in the width direction in the tire circumferential direction.
  2. The heavy-duty tire according to claim 1, wherein part or all of the second portion overlaps the narrow groove in the width direction when projected in the circumferential direction of the tire.
  3. The heavy-duty tire according to claim 1 or 2, wherein the first portion communicates with the widthwise narrow groove, or with a line projected in the widthwise direction from the end portion of the widthwise narrow groove.
  4. The heavy-duty tire according to claim 1 or 2, wherein the circumferential length of the first portion of the tire is 20% to 80% of the average circumferential distance between two adjacent narrow grooves in the width direction.
  5. The heavy-duty tire according to claim 1 or 2, wherein the amplitude of the zigzag grooves is 5% to 20% of the average distance in the tire width direction between two adjacent zigzag grooves in the tire width direction.
  6. The heavy-duty tire according to claim 1 or 2, wherein the inclination angle of the second portion with respect to the tire's circumferential direction is 20 to 70°.
  7. The aforementioned narrow groove in the width direction consists of a portion with a constant groove width and a bottom portion located radially inward of the portion with a constant groove width, where part or all of the groove width is greater than that of the portion with a constant groove width. The heavy-duty tire according to claim 1 or 2, wherein the depth of the portion with a constant groove width is 30% or more and 85% or less of the total depth of the narrow groove in the width direction.
  8. The aforementioned narrow grooves in the width direction are flask-shaped grooves, as described in claim 1 or 2, for heavy-duty tires.
  9. The heavy-duty tire according to claim 1 or 2, wherein the groove depth of the aforementioned narrow grooves in the width direction is 70 to 200 mm.
  10. The aforementioned narrow groove in the width direction consists of a portion with a constant groove width and a bottom portion located radially inward of the portion with a constant groove width, where part or all of the groove width is greater than that of the portion with a constant groove width. In a cross-sectional view at a cross-section perpendicular to the groove width, the bottom portion has curvature. The heavy-duty tire according to claim 1 or 2, wherein the radius of curvature of the bottom surface of the bottom portion is 60% or more and 125% or less of the groove width of the portion with a constant groove width.
  11. The aforementioned narrow groove in the width direction consists of a portion with a constant groove width and a bottom portion located radially inward of the portion with a constant groove width, where part or all of the groove width is greater than that of the portion with a constant groove width. The heavy-duty tire according to claim 1 or 2, wherein, in a cross-sectional view at a cross-section perpendicular to the groove width, the maximum width of the bottom portion is 120% or more and 250% or less of the groove width in the portion with a constant groove width.
  12. A heavy-duty tire according to claim 1 or 2, having a cross-sectional width of 450 mm or more and an outer diameter of 1750 mm or more.
  13. The tread surface has one or more zigzag grooves extending in a zigzag pattern in the circumferential direction of the tire, and multiple widthwise grooves extending in the width direction of the tire. The ratio of the groove width of the zigzag groove to the tread width is 4.5% or less. The ratio of the groove width of the narrow grooves in the width direction to the tread width is 4.5% or less. The zigzag groove consists of a first portion extending in the circumferential direction of the tire and a second portion extending at an inclination with respect to the circumferential direction of the tire, wherein two adjacent second portions sandwiching the first portion are inclined in opposite directions with respect to the circumferential direction of the tire. A heavy-duty tire characterized in that the second portion is located between two adjacent narrow grooves in the width direction in the tire circumferential direction.

Description

This invention relates to heavy-duty tires. Conventionally, heavy-duty tires have had grooves on the tread surface to improve heat dissipation. In contrast, for example, Patent Document 1 proposes using narrow grooves to ensure heat dissipation while also maintaining rubber volume and improving wear resistance. Japanese Patent Publication No. 2008-13037 This is an exploded view showing the tread pattern of a heavy-duty tire according to one embodiment of the present invention.This is a diagram illustrating the shape and dimensions of the zigzag groove.This is a cross-sectional view illustrating the shape of the narrow grooves in the width direction.This is a cross-sectional view illustrating the shape of the narrow grooves in the width direction.This is a schematic diagram illustrating the measurement of strain generated at the bottom of a narrow groove in the width direction.This is a schematic diagram illustrating the time evolution of strain occurring at the groove bottom of a narrow groove in the width direction, in comparison to the case of a small tire size.This is a schematic diagram illustrating the tensile strain that occurs during kicking.This is a schematic diagram illustrating the tensile strain that occurs during push-off when the volume of the groove bottom is large.This figure shows the tire tread pattern of the comparative example.This figure shows the tread pattern of a tire according to Invention Example 1.This figure shows the tread pattern of a tire according to Invention Example 2.This figure shows the tread pattern of a tire according to Invention Example 3. The embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is an exploded view showing the tread pattern of a heavy-duty tire (hereinafter also simply referred to as "tire") according to one embodiment of the present invention. While the internal structure of the tire can be configured similarly to conventional tires, and therefore a detailed explanation is omitted, one example is a tire comprising a pair of bead sections, a carcass toroidally spanning the bead sections, a belt positioned radially outward from the carcass, and a tread positioned radially outward from the belt. The tire of this embodiment is a radial tire, and more specifically, a radial tire for mining and construction vehicles. As shown in Figure 1, this tire has one or more zigzag grooves 2 extending in a zigzag pattern in the circumferential direction of the tire, and multiple widthwise grooves 3 extending in the tire width direction, on the tread surface 1. Furthermore, this tire also has multiple lug grooves 4 communicating with the tread edge TE. In the illustrated example, three zigzag grooves 2 are arranged on the tread surface 1. In the illustrated example, the tread surface 1 has three zigzag grooves 2: one extending in a zigzag pattern along the tire equatorial plane CL, one zigzag groove 2 positioned in one half of the tire width direction with the tire equatorial plane CL as the boundary, and another zigzag groove 2 positioned in the other half of the tire width direction with the tire equatorial plane CL as the boundary. Alternatively, the zigzag grooves 2 may be arranged only in the center (for example, on the tire equatorial plane CL), or only in the shoulder area. The groove width (opening width) of the zigzag groove 2 is 20.0 mm or less. Preferably, the groove width (opening width) of the zigzag groove 2 is 5.0 mm or more. Preferably, the groove depth (maximum depth) of the zigzag groove 2 is 70 mm or more and 200 mm or less. Alternatively, the ratio of the groove width of the zigzag grooves 2 to the tread width is 4.5% or less. Preferably, the ratio of the groove width of the zigzag grooves 2 to the tread width is 0.3% or more. Figure 2 illustrates the shape and dimensions of the zigzag groove 2. As shown in Figures 1 and 2, the zigzag groove 2 consists of a first portion 2a extending in the tire circumferential direction and second portions 2b1 and 2b2 extending at an angle to the tire circumferential direction. The two adjacent second portions 2b1 and 2b2, separated by the first portion 2a, are inclined in opposite directions relative to the tire circumferential direction. In the illustrated example, the first portion 2a extends without inclination with respect to the tire circumferential direction, but it may also extend with an inclination angle of 5° or less with respect to the tire circumferential direction. The circumferential length a of the first portion 2a is preferably 20% to 80% of the average distance in the tire circumferential direction between two adjacent narrow grooves 3 in the width direction. The second portions 2b1 and 2b2 are preferably inclined at an angle θ of 20 to 70° with respect to the tire circumferential direction. In the illustrated example, the second portion 2b1 extends from the upper right to the lower left, and the second portion 2b2 extends from the upper