Pneumatic tire

• US 20040050470A1
• Filed: 07/18/2003
• Published: 03/18/2004
• Est. Priority Date: 10/11/2001
• Status: Abandoned Application

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Nishi, Minoru
• Application Number:
  US10/466,868
• Publication Number:
  US 20040050470A1
• Time in Patent Office: Days
• US Class Current: 152/209.5
• CPC Class Codes: B60C 11/01 Shape of the shoulders between tread and sidewall, e.g. rounded, stepped or cantilevered
• CPC Class Codes: B60C 11/0309 further characterised by the groove cross-section
• CPC Class Codes: B60C 11/13 characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
• CPC Class Codes: B60C 11/1346 covered by a rubber different from the tread rubber

Abstract

In a pneumatic tire, a uneven wear-preventing narrow groove 4 is formed on a tread surface 2a extending from a tread edge E in a tire circumferential direction inside a tire axial direction at a small distance L. At least a groove bottom surface 4b of the narrow groove 4 and an outer groove wall surface 4o outside of the tire axial direction are formed of crack-resistant layers 9 made of crack-resistant rubber material Cg having excellent crack-resistance. A thickness t1 of the crack-resistant layer 9 perpendicular to the groove bottom surface 4b at right angles in a tire radial direction is set to 1 to 5 mm, and a thickness t2 perpendicular to the outer groove wall surface 4o at right angles is set to 1 to 6 mm.

Claims

1. A pneumatic tire in which an uneven wear-preventing narrow groove is formed on a tread surface extending from a tread edge in a tire circumferential direction inside a tire axial direction at a small distance, wherein

at least a groove bottom surface of said narrow groove and an outer groove wall surface outside of the tire axial direction are formed of crack-resistant layers made of crack-resistant rubber material having excellent crack-resistance,

a thickness t1 of said crack-resistant layer at the groove bottom surface in a tire radial direction is set to 1 to 5 mm, and a thickness t2 perpendicular to said outer groove wall surface at right angles is set to 1 to 6 mm.

2. A pneumatic tire according to claim 1, wherein

an inner groove wall surface of said narrow groove inside the tire axial direction is also formed of crack-resistant layer using the crack-resistant rubber material, the crack-resistant layer has substantially U-shaped cross section, a thickness t3 of the crack-resistant layer perpendicular to said inner groove wall surface is set to 2 mm or less.

3. A pneumatic tire according to 1 or 2, wherein

a tensile strength of said crack-resistant rubber material is 23 to 28 MPa, and elongation at the time of cutting thereof is 550 to 620%.

4. A pneumatic tire according to 3, wherein

in a state in which said crack-resistant rubber material is left in atmosphere of 100°

C. for 72 hours, the tensile strength thereof is 22 MPa or higher and the elongation at the time of cutting is 480% or higher.