Depressed radial tire

• US 4,884,610 A
• Filed: 07/05/1988
• Issued: 12/05/1989
• Est. Priority Date: 07/06/1987
• Status: Expired due to Term

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Saito, Kenji
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/215,385
• Time in Patent Office: 518 Days
• Field of Search: 152/454, 152/456, 152/455, 152/538, 152/539
• US Class Current: 152/454
• CPC Class Codes: B60C 3/04 characterised by the relative dimensions of the section, e.g. low profile B60C3/06 takes precedence
• CPC Class Codes: B60C 9/0292 Carcass ply curvature sidewall curvature B60C13/003

Abstract

A depressed radial tire having an aspect ratio of 65% or less, wherein a carcass line (5) ranging from a part (A) under the edge of a belt (6) to a part (C) about the upper end of a bead core (4) comprises an upper arc (7) having the center inside the tire and a lower arc (8) having the center outside the tire; and the radius of curvature (R1) of the upper arc divided by the radius of curvature (R2) of the lower arc is less than 0.8, whereby riding comfort is improved at no sacrifice to the steering stability.

Claims

1. A radial tire having an aspect ratio of 65% or less, comprising:

a pair of bead cores disposed in bead portions of the tire;

a carcass having at least one ply of cords turned up at its ends around bead cores, and defining a carcass line; and

;

3. The radial tire as set forth in claim 1, wherein the product of the belt width/carcass sectional height ratio and the aspect ratio is larger than 0.8.

4. The radial tire as set forth in claim 1 or claim 2, wherein the radius of curvature of the lower arc is in a range of 0.4 to 0.6 times the carcass sectional height.

5. The radial tire as set forth in claim 1, wherein the center of the upper arc is located on a line extending generally parallel to the tire axis from a maximum tire section width point, the center of the lower arc is located on the bead base line, and a point of inflection between the upper and lower arcs is located between the maximum tire section width point and said point adjacent the upper end of the bead core.

7. The radial tire as set forth in claim 3, wherein the center of the upper arc is located on a line extending generally parallel to the tire axis from a maximum tire section width point, the center of the lower arc is located on the bead base line, and a point of inflection between the upper and lower arcs is located between the maximum tire section width point and said point adjacent the upper end of the bead core.

2. a belt on the carcass, having at least two plies of metallic cords, and defining a belt width, characterized in that

the carcass line ranging from a point under the edge of the belt to a point adjacent the upper end of the bead core comprises only two arcs of an upper arc having a center of curvature located inside the tire and a lower arc having a center of curvature located outside the tire;

and

the radius of curvature of the upper arc divided by the radius of curvature of the lower arc is less than 0.8.

6. The radial tire as set forth in claim 2, wherein the center of the upper arc is located on a line extending generally parallel to the tire axis from a maximum tire section width point, the center of the lower arc is located on the bead base line, and a point of inflection between the upper and lower arcs is located between the maximum tire section width point and said point adjacent the upper end of the bead core.