| 摘要 |
PROBLEM TO BE SOLVED: To provide a sewing machine wherein assembly of an electric motor is simplified to solve the problem of recurring errors during the assembly of the electric motor particularly after disassembly in a maintenance or repairing operation. SOLUTION: The sewing machine includes a basal plate, an upper arm to support a driving arm shaft and a standard to integrate the basal plate and the upper arm. A driving device of the arm shaft is formed by an electric motor (12) which is equipped with a rotor (40) and a stator (33). The rotor (40) which is non-rotatably connected to the driving shaft includes a rotor structure (41) and two or more permanent magnets (46) accommodated in recesses (42-45) which are complementary of the rotor structure (41). The shapes of the recesses (42-45) are unsymmetrical so that the individual permanent magnets (46) are accommodated in the individual recesses (42-45) exactly allocated in one magnetic orientation. By this reliability, a defect of the rotor structure having the wrongly oriented permanent magnets is eliminated. COPYRIGHT: (C)2006,JPO&NCIPI
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