Electrical-steel-sheet formed body for rotor core, rotor, rotary electric machine and related method

A built-in permanent magnet type rotary electric machine, comprising:

• a stator;
• a winding disposed in the stator;
• and
• a rotor disposed in opposition to the stator, the rotor being provided with:
• a permanent magnet;
• and
• an electrical-steel-sheet formed body having an opening portion for insertion of the permanent magnet and including an outer-peripheral hardened portion, which is formed in the electrical-steel-sheet formed body at an outer periphery side thereof and which has a higher hardness than a remaining area of the electrical-steel-sheet formed body.

A method of manufacturing an electrical-steel-sheet formed body for use in forming a rotor core of an built-in permanent magnet type rotary electric machine, the method comprising:

• preparing an electrical steel sheet;
• forming an opening portion in the electrical steel sheet for insertion of a permanent magnet therein;
• forming a contoured shape of the electrical steel sheet corresponding to a contoured shape of a rotor;
• and
• forming an outer-peripheral hardened portion on the electrical-steel-sheet formed body to have a higher hardness than a remaining area of the electrical steel sheet by applying an external action thereto such that the outer-peripheral hardened portion is located at an outer periphery side of the electrical steel sheet.