| 摘要 |
PROBLEM TO BE SOLVED: To increase magnetic attraction force volume of a permanent magnet, by providing an axle and a permanent magnet and a wheel arranged around the axle, also providing a void between the permanent magnet and the wheel. SOLUTION: A non-magnetic wheel 13 is fitted to an axle part of a part constituted by a single ring-shaped permanent magnet 12 and a pair of ferromagnetic wheels 11, 11 in which this permanent magnet 12 is interposed and held from both sides. Both end parts of the axle 13 in the axle direction are protruded, magnetic poles N, S of the permanent magnet 12 are formed parallelly to the axial direction of the axle 13. An external diametric part of the axle 13 and an internal diametric part of the wheels 11, 11 are closely arranged. However, between an external diametric surface of the axle 13 and an internal diametric surface of the permanent magnet 12, a void part 15 is provided, magnetic flux f2 not contributing to improvement of attraction force is controlled, magnetic flux f1 contributing to improvement of attraction force is increased. |
