US 7,543,489 B2
Method and device for determining endstage of lifetime of run-flat tire under run-flat state
Atsushi Abe, Yokohama (Japan); and Eishi Ichihara, Sayama (Japan)
Assigned to Bridgestone Corporation, Tokyo (Japan)
Appl. No. 11/578,059
PCT Filed Apr. 05, 2005, PCT No. PCT/JP2005/006662
§ 371(c)(1), (2), (4) Date Jan. 23, 2008,
PCT Pub. No. WO2005/100053, PCT Pub. Date Oct. 27, 2005.
Claims priority of application No. 2004-116585 (JP), filed on Apr. 12, 2004.
Prior Publication US 2008/0115573 A1, May 22, 2008
Int. Cl. G01M 17/02 (2006.01)
U.S. Cl. 73—146  [340/442] 15 Claims
OG exemplary drawing
 
1. A method for determining an end stage of lifetime of a run-flat tire under a run-flat state, comprising steps of;
monitoring the tire internal pressure on a vehicle equipped with a run-flat tire system comprising run-flat tires and tire information transmitter to determine that the tire starts running under a run-flat state when the tire internal pressure becomes lower than a given internal pressure;
measuring the temperature of the tire during running at the run-flat state;
calculating a rate of change in temperature per unit time based on the measured temperature value of the tire; and
comparing the rate of change with a given negative threshold to determine that the run-flat tire is in an end stage of lifetime under a run-flat state when the rate of change in temperature is smaller than the given threshold.