Device and method for detecting force acting on tire

A method for detecting force acting on a tire that is attached to a disk wheel that rotates around an axle, by using a detecting device that includes:

• a rotation body that is provided between the axle and the disk wheel and is integrally rotatable with the disk wheel around the axle,
• axle-side linking portions that are included in the rotation body and linked with the axle;
• wheel-side linking portions that are included in the rotation body and linked with the disk wheel;
• at least two pairs of a first load sensor and a second load sensor, wherein the first load sensor is arranged, in a rotational direction around the axle, in an order of a first axle-side linking portion, the first load sensor, and a first wheel-side linking portion, wherein the second load sensor is arranged, in the rotational direction around the axle, in an order of the first wheel-side linking portion, the second load sensor, and a second axle-side linking portion;
• and
• sandwiched portions, each of the sandwiched portions being provided between the a respective axle-side linking portion and a respective wheel-side linking portion, wherein each of the sandwiched portions includes one of the first load sensor and the second load sensor, and is formed of a member that is elastically deformable around the axle,
• wherein, when a torque around the axle is transmitted to the rotation body from one of the axle-side linking portion and the wheel-side linking portion, the axle-side linking portion and the wheel-side linking portion cause the sandwiched portions to be elastically deformed,
• wherein, when the sandwiched portions are deformed, one of the first load sensor and the second load sensor detects a value by receiving compression force while the other detects a value by receiving extension force,
• wherein the first load sensor of one pair of the two pairs is designated as a third load sensor, while the second load sensor of the one pair is designated as a fourth load sensor,
• wherein at least one sensor group is constituted by the first load sensor, the second load sensor, the third load sensor, and the fourth load sensor,
• wherein the four load sensors are arranged in an order of the first load sensor, the second load sensor, the third load sensor, and the fourth load sensor, on a circumference of a circle having a center that is on a rotational axis of the axle, with 90-degree intervals,
• wherein the force acting on the tire is detected only based on values detected by the at least one sensor group,
• wherein a detection load in the rotational direction detected by the first load sensor is defined as F1,
• a detection load in a direction reverse to the rotational direction detected by the second load sensor is defined as F2,
• a detection load in the rotational direction detected by the third load sensor is defined as F3,
• a detection load in the direction reverse to the rotational direction detected by the fourth load sensor is defined as F4,
• a distance from a center of the rotation body to each of the load sensors is defined as Rs,
• a radius of the tire is defined as Rt,
• a rotation torque is defined as T, and
• wherein T is expressed by a first formula:
• T={(F1+F3)−(F2+F4)}×Rs,
• the force acting on the tire that is vertically applied is defined as Fcs,
• the method comprising:
• a step of detecting the force acting on the tire, defined as Fcs, using a second formula:
• Fcs={(F1−F3)2+(F2−F4)2(T/Rt)2}1/2.