JPS5746647A - Manufacture of mold commutator - Google Patents

Abstract

PURPOSE:To contrive the rationalization of a working process and to improve productivity by a method wherein a metal cylinder having a plurality of grooves in the inner peripheral surface is cut into the predetermined length and a commutator is made by molding by using a projection section formed at the cut end surface in cutting the metal cylinder as a hook section. CONSTITUTION:A metal pipe 10 having a plurality of grooves 9 in the inner peripheral surface is cut into the predetermined length. At that time, a cutting tool 11 having the tip formed in triangular shape is used as a cutting tool and commutator segments 2 having projecting sections 6 with a falling gradient toward the external side are formed on the inside diameter side of the cut end surface. The commutator segments 2 are fixed concentrically with a boss metal fittings 5 after unitedly molding the boss metal fittings 5 with an insulator 3, a commutator 1 is made by performing cutting finish for the outside diameter of a sliding section, an under cut cutting process, a riser cut cutting process and the like. In this way, a projection 6 at the time of a cutting process works as the hook sections of the commutator segments 2, accordingly, a process for forming separate hook sections can be eliminated.