Stepping motor and driving method thereof

摘要

A stepping motor includes a primary side magnetic flux generator unit having a plurality of magnetic poles and a secondary side magnetic member provided rotatably in the primary side magnetic flux generator, characterized in the primary side magnetic flux generator unit generating a magnetic flux passing through a magnetic flux path formed by at least two of the magnetic poles and the secondary side magnetic member to produce an attraction force between the magnetic poles and the secondary side magnetic members for thereby moving one of the primary side magnetic flux generator unit and the secondary side magnetic member, the magnetic poles having coils respectively provided therebetween and having a semihard magnetic member provided over tip ends thereof forming a magnetic flux path among a plurality of the magnetic poles, the semihard magnetic member being magnetized by a magnetic flux produced in the magnetic flux path every time the magnetic flux is produced, the semihard magnetic member producing a magnetic flux directed in the opposite direction to that of a residual magnetic flux formed between each of the magnetic poles and a secondary side magnetic member when the primary side magnetic flux generator means stops the generation of the magnetic flux, thereby cancelling the residual magnetic flux.