Bridgestone/firestone, Inc.

Bridgestone/firestone Research, Inc.

Bridgestone Firestone North American Tire, LLC

David A Johnson

James G Guspodin

John J Regallis

Neel K Mani

Martin A Yurjevich

Michael A Berzins

Brian J Queiser

Donald E Andrews

James F Siegfried

William P Stanfield

Gregg Rasor

David H Soyster

An improved method for determining an initial flat spot magnitude on a tire that has been resting for a period of time on a substantially flat surface uses regression analysis. In accordance with the method, values of a tire flat spot magnitude for a particular type of tire are determined at a number of measurement intervals by a uniformity machine that spins the tire. An equation having at least two exponentially decaying terms is then determined that corresponds to the measured data points. Regression analysis is then used to determine an estimate for an initial flat spot magnitude. The method can be used to evaluate the effectiveness of different tire designs with respect to flat spot recovery rates.

Method for approximating tire flat spot decay and magnitude using regressive analysis

Tire tread

A portable machine for testing on site the uniformity of a tire or other components of a tire/wheel assembly. A compact rigid frame has a base formed by a plurality of longitudinal and transverse frame members for supporting the machine on a planar surface. A box-like subframe is mounted on the base and supports a mounting plate for the tire/wheel assembly. The mounting plate is slidably mounted on a pair of slide rods extending upwardly from the subframe. A road wheel and drive motor are mounted on the base, with the motor being mounted within the subframe and the load wheel being located beneath the tire/wheel assembly mounting plate. An air spring raises and lowers the mounting plate for placement and removal of a tire/wheel assembly thereon. A loading mechanism applies a force on the tire/wheel assembly mounting plate to forceably move a tire into contact with the road wheel, and is measurable by a first load cell. A second load cell is mounted on a spindle of the tire/wheel assembly mounting plate and measures forces exerted on the tire along five separate axes. A probe located adjacent a tire being tested transmits signals to an electronic processing unit which generates a graphic display of the tire's uniformity.

Portable tire uniformity test machine

A pneumatic safety tire, of the type preferably having a section height of five inches or greater, having a pair of crescent shaped elastomeric reinforcing members located between the innerliner and side wall and extending from adjacent the tread shoulders to at least the apex of the bead fillers of the tire. A pair of bias reinforcing plies are located between the elastomeric reinforcing members and the side walls of the tire and extend along the side walls from adjacent the tread shoulders to below the top most turn-up ends of the body ply. The elastomeric reinforcing members preferably are similar in composition to that of the bead fillers and have a low hysteresis value preferably within the range of 0.03 and 0.11, a high modulus preferably within the range of 2600 psi and 2800 psi and a Shore A hardness preferably within the range of between 85 and 91. The elastomeric reinforcing members in combination with the reinforcing bias plies, enable a high section height tire to run at high speeds for a relatively long distance in an uninflated condition, and improve the performance of heretofore low section height run flat tires.

Pneumatic safety tire

Growing community of inventors

Wadsworth, OH, United States of America

David A Johnson