| 摘要 |
PURPOSE: To rotate a rotor to a selectable position by enabling each of a magnetic field that is induced by a stator, a rotor, and a bias magnet to have simply one pair of N-S magnetic poles and enabling a bias magnet means to direct the magnetic poles so that they are away by 90 deg. for the stator. CONSTITUTION: A stator has an outer field cup 10A and an inner field cup 10B made of a permeable material. First and second magnetic pole pieces are formed by the circular parts of the field cups 10A and 10B that are arranged adjacently at the different sectors of the peripheral edge regions of an orifice. The field cups form a ring-shaped space that surrounds each magnetic pole piece, and a stator coil winding 18 is arranged within the space. Then, when current is allowed to flow to the coil winding in a first direction, N and S poles are induced in the first and second magnetic pole pieces. Also, when current is allowed to the coil winding in a second direction that is opposite to the first direction, a magnetic pole with an opposite polarity is induced at the first and second magnetic poles, thus rotating the rotor to a selectable position. |
