Patent ID: 7030608

Claim:
A rotational angle sensing device for measuring a relative rotational angle between two members, which make relative rotation therebetween, the rotational angle sensing device comprising: a magnet that is provided to one of the two members and is configured into one of a ring shape and a circular disk shape, wherein a center of an outer peripheral edge circle, which is defined by an outer peripheral edge of the magnet, substantially coincides with a rotational axis of the relative rotation, and the magnet includes a magnetic flux generating portion and a magnetic flux attracting portion, which are diametrically opposed to each other; and first and second magnetic sensing elements that are arranged adjacent to each other and are provided to the other one of the two members, wherein a magnetic sensing surface of the first magnetic sensing element is generally perpendicular to a magnetic sensing surface of the second magnetic sensing element, and the relative rotational angle between the two members is determined through the first and second magnetic sensing elements based on a magnetic flux, which is generated by the magnetic flux generating portion and passes through the first and second magnetic sensing elements toward the magnetic flux attracting portion.