Patent ID: 8810239

Claim:
An angle sensor, comprising: a ring-shaped main gear configured to rotate with a steering shaft; a second subsidiary gear engaged with the main gear, including a second magnet being coupled to a surface of the second subsidiary gear; a first subsidiary gear engaged with the second subsidiary gear and configured to rotate by rotation of the main gear, with a first magnet being coupled to a surface of the first subsidiary gear; and a magnetic device detecting a change in magnetic field of the first magnet or the second magnet and outputting data of a rotation amount; wherein the first subsidiary gear is configured to rotate four times while the main gear rotates once, such that a rotation amount of the steering shaft is measured, and wherein when the main gear rotates, the second subsidiary gear rotates reversely with respect to rotating direction of the main gear, while the first subsidiary gear rotates in a same rotating direction as that of the main gear.