US Patent 9502929 Rotor and motor

A rotor with a first rotor core, a second rotor core, a field magnet, and an interpole magnet is provided. The first rotor core has a first core base and a plurality of first nail-shaped magnetic pole parts that extend in the axis direction from the outer circumference section of the first core base. The second rotor core has a second core base and a plurality of second nail-shaped magnetic pole parts that extend in the axis direction from the outer circumference section of the second core base. The field magnet is magnetized along the axis direction and makes the first nail-shaped magnetic parts function as first magnetic poles and the second nail-shaped magnetic parts function as second magnetic poles. The interpole magnet is arranged between the first nail-shaped magnetic parts and the second nail-shaped magnetic parts. The interpole magnet has the same polarity as the first and second nail-shaped magnetic pole parts, in the sections where same face the first and second nail-shaped magnetic pole parts.