Stepping motor, method of driving the same and drive circuit therefor

摘要

A stepping motor includes a first element including at least two permanent magnets each having a pair of N and S poles and a second element including a yoke arranged to be separated from the first element by a predetermined interval. The first and second elements can be moved relative to each other. The second element has a two-phase coil arranged on the yoke in association with a width of each pole in a moving direction of the permanent magnet and detent torque generating means for generating a static detent torque by relative movement. The detent torque generating means is arranged on the yoke such that a stable position of one of the first and second elements moved by a dynamic torque generated when one of the coils constituting the two-phase coil is energized is deviated from a stable position of a moving element caused by a detent torque generated from the detent torque generating means. A method of controlling the stepping motor is also disclosed.