Patent ID: 7302868
Filing Date: 2007-12-04
Classification: B60C,B60T,G01L

Abstract:
1. A method for measuring at least one of forces in a peripheral direction and a radial direction of a running tire mounted onto a rim acted upon a ground contact face, in which when a point on an outer peripheral face of the rim is Q and an intersect between a straight line passing through the point Q under no action of external force and extending in the radial direction and an inner peripheral face of a tread portion of the tire is P, said forces are determined from a variant pattern that a relative displacement of the point P to the point Q in the peripheral direction or the radial direction is changed in accordance with a rotating position of the point Q when the point P passes through the ground contact portion of the tire, wherein a magnetic field formed by a magnet arranged on one of the point P and the point Q is continuously measured by a magnetic sensor arranged on the other of the point P and the point Q, and the variant pattern of the relative displacement between the point P and the point Q is determined by reverse calculation from a variant pattern of a magnetic flux density changed in accordance with the relative displacement; and wherein the measurement of the magnetic flux density is conducted by using the magnet arranged so that a magnetic force line distribution of the magnetic field forms a plane symmetry with respect to a meridional plane of the tire including the point P or the point Q under no action of external force to the tire, and the force acting in the peripheral direction of the tire is determined from an average between maximum value and minimum value of a variant pattern of a tire peripheral component in the measured magnetic flux density and the force acting in the radial direction of the tire is determined from a difference between the maximum value and the minimum value of the variant pattern.