Abstract: A magnetic field-generating device includes a pair of permanent magnet components disposed in such a manner as to face each other with a gap formed therebetween, a yoke for magnetically coupling the pair of permanent magnet components, and pole pieces which are each fixed to a surface of a corresponding permanent magnet component that faces the gap. The magnetic field generating device is adpated to generate a magnetic field in the gap. Each of the pole pieces is made of a laminate of magnetic plates which laminated in a direction substantially perpendicular to the sides of the solid care portion.

Abstract: A magnetic field generating device for nuclear magnetic resonance-computerized tomography of the type wherein permanent magnet assemblies of a pair opposing mutually to define an air gap therebetween are magnetically coupled together by yoke means to create a magnetic field within the air gap is provided, which is characterized in that each permanent magnet assembly comprises a flat plate-like central permanent magnet and peripheral permanent magnets arranged around the central permanent magnet and inclined toward the inside of the air gap, the magnetic pole surface of each permanent magnet assembly forms a curved concave face with respect to the air gap, and each permanent magnet is magnetized in the direction perpendicular to the corresponding magnetic pole surface, whereby the leakage flux is reduced and the magnetic efficiency is enhanced, thus, reduction of the device dimension and weight can be achieved.

Abstract: A magnetic field generating device for a nuclear magnetic resonance-computerized tomography comprising a pair of permanent magnets magnetized in the same direction with different-polarity poles opposing mutually to define an air gap, whose maximum energy product, (BH).sub.max, is not less than 30 MGOe (240 KJ/m.sup.3), on each of the opposing faces of the permanent magnets a magnetic pole segment being provided which has an annular projection and, as occasion demands, at least one central convex projection inside the annular projection, and the permanent magnets being coupled magnetically by a yoke to generate a magnetic field within the air gap.The present device is able to create a uniform and stable magnetic field, in spite of its small-sized body.

Abstract: A magnetic field pole assembly for a direct-current motor comprises a nonmagnetic support member, a plurality of even pole pieces disposed in the support member and angularly spaced in symmetrical relationship around a central axis of the support member, a pair of permanent magnets mounted one on each side of each pole piece and having like plarities confronting each other across the pole piece, and yokes disposed between adjacent pole pieces and connected to and between those adjacent permanent magnets which are mounted on the adjacent pole pieces. Each of the permanent magnets is in the form of a plate magnetized in the direction of plate thickness and having one magnetic pole surface secured to a side of one of the pole pieces.