TIRE TREAD RADIUS MEASUREMENT METHOD AND TREAD RADIUS MEASUREMENT DEVICE USED IN SAME

摘要

The present invention accurately measures the tread radius of a rotating tire. A tread radius measurement method is provided with a tread radius measurement process including a measurement step, an averaging step, and a calculation step. In the measurement step, three laser displacement meters are used to measure the radial distance to the tread surface of a rotating tire and a number m of each radial direction distance data item (y1, y2, y3) is acquired for each tire rotation. In the averaging step, m of each radial direction distance data item (y1, y2, y3) are smoothed, and the remaining radial direction distance data having the noise data removed therefrom is averaged to produce averaged values (y1N, y2N, y3N). In the calculation step, a tread radius (TR) is calculated from the averaged values (y1N, y2N, y3N) and the distances (x1, x2, x3) of the laser displacement meters in the axial direction of the tire.