Patent attributes
An attachment fitting is attached inside a rotor hole. The attachment fitting is made up of a main body, first and second pieces disposed in a piece placement hole formed in the main body so as to pass therethrough in a direction orthogonal to a rotation central axis of a rotor, a leaf spring including two arm portions, and a retainer that is mounted on the main body and puts a base of the leaf spring between the retainer and the main body. The first and second pieces have grooves into which the arm portions of the leaf spring are inserted. When the rotor rotates, the first and second pieces protrude from the piece placement hole by the centrifugal force against the spring force of the leaf spring and make contact with a rotor coupling portion of a shaft.
