METHOD AND APPARATUS FOR REDUCING LATERAL FORCE VARIATIONS AND OVERTURNING MOMENT VARIATIONS IN PNEUMATIC TIRES

摘要

METHOD AND APPARATUS FOR REDUCING LATERAL FORCE VARIATIONSAND OVERTURNING MOMENT VARIATIONS IN PNEUMATIC TIRESAbstract of the DisclosureA method and apparatus for reducing lateral forcevariations and overturning moment variations in pneumatictires by detecting the magnitude, direction and location ofsuch variations and alternatingly grinding off opposite por-tions of the two shoulders of the tire tread. A tire ismounted on a test rim, inflated to operating pressure, androtated under a normal service load against a loading drum.Force variations in the lateral and radial directions aredetected and measured by load cells operatively associatedwith the drum axle and located at opposite ends of the axle.The sum of the lateral force variation forces or the dif-ference of the radial force variation forces measured by theload cells provides a voltage level signal representative ofthe direction, magnitude and location of the lateral forcevariation and the overturning moment variation. The phaseangle of this signal is ascertained to determine the loca-tion on the tire of these variations. Where these variationsexceed a preset level, they are reduced by alternatinglygrinding a zone of one shoulder of the tire tread and theopposite zone of the other shoulder of the tire tread inresponse to the phase angle of the variation signals. Re-duction of lateral force variations by this method alsoreduces radial force variation.