Abstract: An improved commutator usable for an electric motor of the type adapted to be press fitted onto the support shaft of a rotor which is accommodated in the motor. The inner wall of the commutator comprises a plurality of larger diameter portions of which inner diameter is larger than the outer diameter of the support shaft and a plurality of press fitting portions of which inner diameter is smaller than the outer diameter of the support shaft. Press fitting of the commutator onto the support shaft is achieved by elastic bending deformation of the press fitting portions on the inner wall of the commutator in the outward direction. Typically, the inner wall of the commutator comprises three larger diameter portions and three press fitting portions. No preliminary machining is required on the inner wall of the commutator before press fitting is effected. The amount of press fitting allowance can be increased remarkably compared with any conventional commutator.

Abstract: A commutator for use with a DC motor or a DC generator. The parent metal of the segments of the commutator is formed with bulging portions which have their outer surfaces generally coextending with the outer surfaces of protecting portions for contacting with brushes. This commutator is manufactured by forming a cylinder of a plate of a conductive material, by forming a plurality of pawls on the circumference of the cylinder, by molding a boss of a synthetic resin in the cylinder, by forming a plurality of notches in one end of the cylinder, and by cutting the trunk of the cylinder into a plurality of slits to form a plurality of separate segments.

Abstract: A commutator for use with a DC motor or a DC generator. The parent metal of the segments of the commutator is formed with bulging portions which have their outer surfaces generally coextending with the outer surfaces of protecting portions for contacting brushes. This commutator is manufactured by forming a cylinder of a plate of a conductive material, by forming a plurality of pawls on the circumference of the cylinder, by molding a boss of a synthetic resin in the cylinder, by forming a plurality of notches in one end of the cylinder, and by cutting the trunk of the cylinder with a plurality of slits to form a plurality of separate segments.