METHOD FOR IMPROVING TREAD NOISE BY RELATIVE ROTATION OF A RIB, AND SIMULATING THE EFFECT THEREOF

摘要

A method is disclosed for evaluating the level of objectionable noise associated with the operation of a tire by virtue of its tread contacting a road surface, which comprises digitizing the tread design on a coordinate system so as to define load-supporting portions of the tread in contact with the pavement, and distinguish them in binary form from those portions of the tread which are not in contact, as multiple matrix elements; defining a generally arcuate profile of a leading or trailing edge of a footprint of the tread by fitting an equation to the edge; sequentially performing the time ensemble summation, of the noise produced by each matrix element, over every matrix element on the entire circumferential surface; converting the sequence of summation to a periodic analog signal; converting the analog signal to a sound; and, aurally evaluating the sound. In a simplified case 0's and 1's along at least one footprint edge are sequentially summed around the circumference of the tire. The system requires only a means for digitizing the tread pattern, a computer to perform the necessary manipulations of data, and a means to convert a digital signal to an analog signal. Having subjectively chosen a tread pattern deemed to have an acceptable noise level, ribs are then relatively rotated one with respect to another to obtain an improved level of tread noise.