BRUSHLESS DISC-TYPE DC MOTOR OR GENERATOR

A brushless, preferably coreless, DC motor or generator characterized by a positive, unidirectional, nearly constant torque. The machine in a preferred form comprises a rotor disc (16, 18) mounted for rotation with a shaft (2) and a stator (28) fixedly mounted in coaxial parallel relation to the rotor. The stator (28) contains at least two interleaved sets (A, B) of coils (26), with the sets of coils adapted to be alternately energized for current flow in the same direction in the plane of the stator to generate axially extending magnetic fields all of the same polarity. The rotor disc (16) carries in a circular array at least one permanent magnet (24), asymmetrically shaped in relation to the shape of the stator coils (26), each having a tip portion (60) and a base portion (62); and with a magnetic field of common polarity extending in the same axial direction as the magnetic fields of the energized coils (26). When the tip portions (60) of the magnets (24) are aligned with a first set (A, B) of coils (26), that set is energized to create a torque on the rotor. The magnets (24) rotate until the tip portions (60) become aligned with the adjacent set (A, B) of coils (26), which are then energized as the first set of coils are simultaneously de-energized. This sequence is continuously repeated to provide a nearly constant output torque. Moteur ou generateur a courant continu sans balai, de preference sans noyau, caracterise par un couple positif, unidirectionnel et pratiquement constant. Dans une forme d'execution preferee, la machine comprend un disque de rotor (16, 18) monte sur un arbre (2) et un stator (28) monte de facon fixe, coaxial et parallele au rotor. Le stator (28) contient au moins deux jeux imbriques (A, B) de bobines (26), ces jeux de bobines etant concus pour etre excites alternativement pour une circulation de courant dans le meme sens dans le plan du stator afin d'engendrer des champs magnetiques axiaux de meme polarite. Le disque de rotor (16) porte, dans une configuration circulaire, au moins un aimant permanent (24) dont la forme est asymetrique par rapport a celle des bobines (26) du stator chacun ayant une partie d'extremite (60) et une partie formant base (62); avec un champ magnetique de polarite commune dirige dans la meme direction axiale que celle des champs magnetique des bobines excitees (26). Lorsque les parties d'extremite (60) des aimants (24) sont alignees avec un premier jeu (A, B) de bobines (26), ce jeu est excite afin de