Rotor of magneto generator

A rotor structure for use in a magneto generator including a yoke of cup-like shape consisting of a cylindrical wall and a side wall extending from one end of said cylindrical wall, a plurality of magnets provided by permanent magnets disposed along the circumference of said cylindrical wall of said yoke in a relation circumferentially spaced apart by a predetermined distance, each said magnet having first and second flat surfaces axially facing each other, an outer peripheral surface curved to conform substantially to the curved contour of the inner surface of said cylindrical wall of said yoke and an inner peripheral surface curved to be substantially coaxial with the curved contour of the inner surface of said cylindrical wall of said yoke, said magnets being arranged in area contact with the inner surface of said cylindrical wall by means of their outer peripheral surfaces, and means for holding said magnets in predetermined positions wherein said holding means comprises a first magnet holding plate disposed on a circumferential shoulder formed at a predetermined position on the inner surface of said cylindrical wall of said yoke, said first magnet holding plate having a surface on which said magnets are disposed in area contact by means of their first flat surfaces, a second magnet holding plate disposed in area contact with the second flat surfaces of said magnets, to axially face said first magnet holding plate, and a third magnet holding plate of cylindrical shape arranged in area contact with the inner peripheral surfaces of said magnets to press said magnets against the inner surface of said cylindrical wall of said yoke.