摘要 |
<p>An electromagnetic coil (51) forms a magnetic circuit (M) for generating an attractive magnetic force for linking a pulley (30) and an armature (40) by causing a magnetic flux to pass multiple times through a boundary between the pulley (30) and the armature (40). A predetermined number of magnetic poles are formed between the pulley (30) and the armature (40), the predetermined number being six or more and representing the number of times the magnetic flux passes through the boundary between the pulley (30) and the armature (40) in the magnetic circuit (M).</p> |