Patent ID: 6725982
Filing Date: 2004-04-27
Classification: H02K

Abstract:
A single-row rotating-type eddy current braking apparatus equipped with a hollow cylindrical rotor mounted on an output shaft or a power transmission shaft,a ferromagnetic support ring which is disposed inside the rotor, a plurality of permanent magnets which are installed on the outer peripheral surface of the support ring at constant intervals and which are arranged so that the orientations of the magnetic poles thereof alternate, a plurality of ferromagnetic switching plates disposed between the plurality of permanent magnets and the rotor at approximately the same installation angles as the installation angles of the plurality of permanent magnets and spaced from the plurality of permanent magnets and the rotor, and a cylindrical support body which is made of a non-magnetic material and which supports the support ring and the plurality of switching plates, the plurality of permanent magnets and the plurality of switching plates being installed so as to be capable of rotating with respect to each other by a prescribed angle with respect to the rotational center of the output shaft or the power transmission shaft, characterized in that when the thickness of the switching plates is T, the width of the switching plates is W, the angle with respect to the center of the output shaft or the power transmission shaft between the same ends of two adjoining switching plates is &THgr;, and the angle with respect to the center of the output shaft or the power transmission shaft between two opposing ends of adjoining permanent magnets is &dgr;&THgr;, the relationship 0.75&lE;(&dgr;&THgr;/&THgr;)Ã—(W/T)&lE;2.5 is satisfied, wherein (&dgr;&THgr;/&THgr;)Ã—(W/T) defines a magnetic coefficient, the magnetic coefficient being satisfied accordineg to the relationship in a vehicle having a final reduction ratio of at most 3.3 to provide improved braking torque and reduced drag torque.