Resilient tires and wheels – Tires – resilient – Anti-skid devices
Reexamination Certificate
1999-08-04
2001-05-29
Johnstone, Adrienne C. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Anti-skid devices
C152S454000, C152S517000, C152S531000, C152S532000, C152S533000, C152S554000
Reexamination Certificate
active
06237661
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pneumatic tire, more particularly to a run-flat tire having an improved tire profile capable of improving run-flat performance of the tire without sacrificing running performance under normal conditions.
2. Description of Related Art
Recently, there is a strong demand for run-flat tires capable of running safely for a certain distance at a usual speed, for example, at a speed of 80 km/h for at least 80 km distance.
Hitherto, widely employed as a means of providing ability to run under flat conditions is to dispose a reinforcing rubber layer in each sidewall portion of a conventional type pneumatic tire. Such tires are disclosed in the laid-open Japanese patent applications JP-A-53-18104, JP-A-64-30809, JP-A-4-154411 for examples.
In such tires, however, it is difficult to satisfy the above-mentioned requirements, at least 80 km distance at 80 km/h, because the sidewall reinforcing layer is inevitably increased in the thickness, volume and weight. And when such a great mass of sidewall reinforcing rubber layer is disposed, tire performance under normally inflated conditions is liable to deteriorate. For example, the tire weight and rolling resistance increase, and fuel consumption of vehicles is increased, and further the ride comfort is not good, and furthermore belt edge loose is liable to occur to decrease the durability.
BRIEF SUMMARY OF THE INVENTION
It is therefore, an object of present invention to provide a run-flat tire in which run-flat performance is improved and at the same time the above-mentioned problems can be solved.
According to one aspect of the present invention, a run-flat tire comprises a tread portion, a pair of sidewall portions, a pair of bead portions with a bead core therein, a carcass comprising a carcass ply extending between the bead portions, and a sidewall reinforcing layer disposed axially inside the carcass ply in each of the sidewall portions, and
in a normally inflated unloaded state, a profile line from a tire equator point in the tread portion to a maximum tire section width point in each sidewall portion is curved substantially along an involute curve so as to have a radius of curvature decreasing continuously from the tire equator point towards the sidewall portion, wherein the basic circle of the involute curve is an ellipse whose major axis extends in the tire radial direction,
the radial distance between the tire equator point and the maximum tire section width point is more than 34% but less than 50% of the tire section height.
REFERENCES:
patent: 5630892 (1997-05-01), Williams et al.
patent: 6073668 (2000-06-01), Iwasaki et al.
patent: 0 748 705 A2 (1996-12-01), None
patent: 0 778 162 A1 (1997-06-01), None
patent: 53-18104 (1978-02-01), None
patent: 64-30809 (1989-02-01), None
patent: 4154411 (1992-05-01), None
patent: 8-337101 (1996-12-01), None
Birch & Stewart Kolasch & Birch, LLP
Johnstone Adrienne C.
Sumitomo Rubber Industries Ltd.
LandOfFree
Run-flat tire with specified profile does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Run-flat tire with specified profile, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Run-flat tire with specified profile will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2447121