| US 7,575,032 B2 | ||
| Pneumatic tire | ||
| Shinsuke Nakamura, Kodaira (Japan) | ||
| Assigned to Bridgestone Corporation, Tokyo (Japan) | ||
| Appl. No. 10/571,473 PCT Filed Sep. 06, 2004, PCT No. PCT/JP2004/012941 § 371(c)(1), (2), (4) Date Mar. 13, 2006, PCT Pub. No. WO2005/025897, PCT Pub. Date Mar. 24, 2005. |
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| Claims priority of application No. 2003-321205 (JP), filed on Sep. 12, 2003. | ||
| Prior Publication US 2006/0272761 A1, Dec. 07, 2006 | ||
| Int. Cl. B60C 15/00 (2006.01); B60C 15/02 (2006.01); B60C 15/024 (2006.01); B60C 15/04 (2006.01) | ||
| U.S. Cl. 152—539 [152/540; 152/544] | 12 Claims |
| 1. A pneumatic tire in which a polygonal bead core having a bottom extending generally along the tire width direction is embedded
in a bead portion, the bead portion having a bead base extending between a bead heel and a bead toe, characterized in that,
in the widthwise section of the tire, when first, second and third base points are defined as intersections of lines extending
radially inward from an outer end point, a widthwise center point and a inner end point of the bottom of the bead core, respectively,
and the bead base, and a maximum displacement point is defined as a point where an interference is maximum, the maximum displacement
point is within a range of 25% or less of the width of the bottom of the bead core with the third base point as the center
of the range, the interference at the maximum displacement point is 1.1-1.3 times as much as the interference at the second
base point, the bead base extends at least between the bead heel and the first base point and has a first tapered portion
with a taper angle being identical with or greater by three degrees or less than a taper angle of a bead seat of a standard
rim,
wherein the bead base has a second tapered portion extending widthwise outwardly from the maximum displacement point and having
a taper angle larger than the taper angle of the bead seat of the standard rim by 10-14 degrees and
a third tapered portion extending widthwise inwardly from the maximum displacement point and having a taper angle identical
to or smaller by five degrees or less than the taper angle of the bead seat of the standard rim,
wherein the first and second tapered portions contact with each other at the second base point.
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