Patent attributes
A motor includes a rotor magnet, a stator, and a magnetic sensor. The rotor magnet includes magnetized portions in a Halbach array, and having radially magnetized portions whose magnetization direction is a radial direction and non-radially magnetized portions. In first and second radially magnetized portions, magnetic poles on both sides in the radial direction are arranged opposite to magnetic poles on both sides in the radial direction of the first radially magnetized portion. The first and second radially magnetized portions are alternately arranged along a circumferential direction with at least one non-radially magnetized portion therebetween. The magnetic sensor is located on the other side in the radial direction with respect to the rotor magnet. A non-magnetized portion is in an axial portion of the rotor magnet where a magnetic field is detected by the magnetic sensor, and located between the first and second radially magnetized portions in the circumferential direction.
