Patent ID: 7841231

Claim:
A steering angle sensing apparatus comprising: a shaft gear coupled to a steering shaft; a first sub gear rotating with the shaft gear; a second sub gear engaged with the first sub gear, and having a gear ratio different from a gear ratio of the first sub gear; a first magnet coupled on an axis of the first sub gear; a second magnet coupled on an axis of the second sub gear; a first and a second angle detecting portion spaced a predetermined distance respectively from the first and second magnets, and respectively outputting rotated hit values corresponding to rotated angles of the first and second magnets, wherein the first and second angle detecting portions are rotary hall integrated circuits; and a steering angle calculating portion that calculates a difference between the rotated bit values outputted by the first and second angle detecting portions, and multiplies a uniform gain value to the calculated difference between the rotated bit values to obtain an absolute steering angle, wherein the first sub gear is formed in the same horizontal plane as the second sub gear.