A RING MAGNET UNIT FOR AN ELECTRIC MOTOR

A ring magnet unit for an electric motor is provided, comprising a circular magnet holder and at least two magnet segments fixed to the magnet holder and arranged in a circumferential direction of the magnet holder, wherein respective one magnet segment has a first surface abutting to a surface of the magnet holder and a second surface which is the opposite surface of the first surface. Both side surfaces of the first surface and the second surface are chamfered in the directions that cross the radial direction of the magnet holder at the same angles. At least one pair of the adjacent two magnet segments comprises one magnet segment whose circumferential length of the first surface is equal to or longer than the circumferential length of the second surface and the other magnet segment whose circumferential length of the first surface is equal to or shorter than the circumferential length of the second surface.