Armature and method for producing armature

A method for producing an armature for an electric motor or a generator including a plurality of split cores mutually connected to form an annular core, the method comprising the steps of:

• connecting a connection projection and a connection recess formed on coupling surfaces located on both ends of each of the split cores in a circumferential direction to the connection recess and the connection projection of an adjacent one of the split cores in a die unit, thereby obtaining a first intermediate body in which the split cores are annularly connected;
• removing the first intermediate body from the die unit;
• disconnecting the connection projection from the connection recess in adjacent ones of the split cores and decoupling the split cores;
• winding a wire on each of the decoupled split cores;
• and
• inserting the connection projection of each of the split cores into the connection projection of the adjacent one of the split cores to reconnect the split cores, thereby obtaining the annular core,
• wherein, in a cross sectional plane perpendicular to a center axis line of the annular core:
• the connection projection and the connection recess have complementary configurations in which the connection projection and the connection recess are narrowed in width with distance from the coupling surfaces;
• each of the connection projection and the connection recess includes a pair of friction surfaces extending in a direction separate from the coupling surfaces;
• at least one of the pair of friction surfaces of the connection projection is inclined relative to a virtual normal line that is perpendicular to a line connecting bottom portions of the pair of friction surfaces of the connection projection;
• and
• at least one of the pair of friction surfaces of the connection recess is inclined relative to a virtual normal line that is perpendicular to a line connecting bottom portions of the pair of friction surfaces of the connection recess.