ROTATION ANGLE DETECTION APPARATUS AND TORQUE SENSOR

PROBLEM TO BE SOLVED: To provide a torque sensor which can be simplified in structure while being able to detect an absolute rotation angle of multi-rotation of a rotating body.SOLUTION: In a torque sensor 14, a steering torque applied to a steering wheel is arithmetically operated based on a differential value between a rotation angle of an input shaft 20 detected through a first resolver 40 and a rotation angle of a lower shaft 21 detected through a second resolver 50. The torque sensor 14 comprises a sun gear 61 which is rotated integrally with the input shaft 20, and a planetary gear mechanism 60 composed of a planetary gear 63 which is formed from a magnetic substance and revolved about the sun gear 61 and an internally toothed gear 62 with which the planetary gear 63 is engaged. On the basis of a voltage signal outputted from the first resolver 40, the rotation angle of the input shaft 20 and a position of the planetary gear 63 are detected and on the basis of these rotation angle and position, a steering angle of the steering wheel is determined.