| 摘要 |
<p>The invention relates to a driving device comprising a ring (3) rotatable about its rotational axis of symmetry (2), which ring at its circumference is provided with magnets (5), and electromagnet means (9) positioned near the ring for enabling to exert a driving power on the ring, wherein the electromagnet means (9) are concentric to the ring and form an incomplete circle part.</p> |
