Method for manufacturing a stator core for a dynamoelectric machine

A method for manufacturing a stator core for a dynamoelectric machine, said method comprising the steps of:

• preparing a cylindrical laminated body by preparing a continuous first sheet in which first recess portions are formed at a predetermined spacing by press-punching from a strip-shaped first magnetic steel sheet material and winding said first sheet into a helical shape such that said first recess portions are superposed in an axial direction;
• preparing a second sheet having a predetermined length in which second recess portions are formed at a predetermined spacing by press-punching a second magnetic steel sheet material having a sheet thickness greater than that of said first magnetic steel sheet material;
• bending said second sheet into an annular shape;
• stacking said second sheets bent into the annular shape on both axial ends of said laminated body such that said second recess portions are superposed on said first recess portions in an axial direction;
• and
• integrating said laminated body and said second sheets stacked together by applying several strips of welding on an outer circumferential surface of said laminated body and said second sheet so as to extend from a first end to a second end in an axial direction,
• wherein abutted portions of said second sheets bent into the annular shape are joined together simultaneously by said welding during the step of integrating said laminated body and said second sheets.