ESTIMATION METHOD OF FORCE APPLIED TO TIRE, AND PNEUMATIC TIRE USED FOR THE METHOD

PROBLEM TO BE SOLVED: To improve an estimate accuracy of a front-back force, a lateral force, and a vertical force applied to a tire.SOLUTION: First strain sensors of which gain maximum lines N are 30-60° and second strain sensors of which maximum lines orient to a tire diameter direction line, are alternately attached to a side with equal intervals therebetween, and, to the another side, strain sensors are attached symmetrically. Three force components Fx, Fy and Fz are estimated by following formulae in which a sum ( VA1+ VB1) of a total sum VA1 of the sensor outputs of the first strain sensors on the side and a total sum VB1 of outputs of the first strain sensors on the another side, a difference of ( VA1- VB1) of these total sums VA1 and VB1, and a sum ( VA2+ VB2) of a total sum VA2 of the sensor outputs of the second strain sensors on the side and a total sum VB2 of the sensor outputs of the second strain sensors on the another side are variable: (1) Fx=Kx×( VA1+ VB1)+Ax; (2) Fy=Ky×( VA1- VB1)+Ay; and (3) Fz=Kz×( VA2+ VB2)+Az, wherein Kx, Ky, Kz, Ax, Ay and Az in the formulae are constants.