| 摘要 |
PROBLEM TO BE SOLVED: To prevent efficiently the magnetic fields of the magnets of an eddy-current decelerator from leaking to its brake drum or its brake disk when not braking. SOLUTION: In the eddy-current decelerator, a brake drum 7 coupled to its rotational shaft has in the inside thereof a guide cylinder 10 having an inner hollow portion with a rectangular section which is formed out of a non-magnetic body. To a magnet holding cylinder 14 stored in a rotatable way in the inner hollow portion of the guide cylinder 10, a plurality of magnets 24 are coupled with equal spaces in its circumferential direction and their polarities to outer cylindrical portions 10a of the guide cylinder 10 are made different from each other alternately in its circumferential direction. Also, an actuator 20 for rotating the magnetic holding cylinder 14 forward or backward is so provided that there are switched by the actuator 20 a non-braking position wherein the two magnets 24 are opposed partially to each of ferromagnetic members 15 whose number is the same as the number of the magnets 24 coupled to the outer cylindrical portions 10a of the guide cylinder 10 and a braking position wherein each magnet 24 is opposed expansively to each ferromagnetic member 15. In this eddy-current decelerator, there are so provided an extension portion 35a obtained by extending the outer surface of the ferromagnetic member 15 in its circumferential direction and an extension portion 36a obtained by extending the inner surface of the ferromagnetic member 15 in the opposite direction to the outer surface that they are overlapped each other with an radial space in between.
|
