Torque sensor using magnetic circuit

The invention discloses a torque sensor using a magnetic circuit and belongs to the technical field of sensors. According to the torque sensor, T magnetic sheets are arranged on the end faces of a driving grade, T is an even number larger than or equal to 4, and the magnetic sheets are evenly distributed on a circumference with the center of the driving grade as the circle center; polarities of S poles and N poles of adjacent magnetic sheets are mutually stagger; two end faces of a driven grade are composed of T/2 sector-shaped high magnetic conduction toothed sheets arranged at intervals respectively, positions of the toothed sheets on the two end faces are opposite, the toothed sheets on the same end face are evenly distributed on the same circumference, the driving grade is located in the driven grade, the driving grade and the driven grade can relative rotate, the magnetic sheets are opposite to the toothed sheets; and a circuit collection board is sleeved outside the edge of the driven grade, the driven