| 摘要 |
A linear stepper motor is provided with a feature to cause it to return to a zero position when current is cut off. The motor is formed of a stator armature assembly and a permanent magnet rotor assembly with poles thereof facing poles of the stator armature. The rotor assembly includes a rotor core formed as a nut with an axial threaded aperture extending therethrough. A shaft assembly includes a shaft screw mating with the rotor core nut, a front shaft affixed thereto, and a fixed sleeve overfitting the front shaft to permit axial motion thereof. A ball-and-groove arrangement in the front shaft and the sleeve prevents rotation of the shaft without impairing axial movement thereof. A spring causes return of the shaft to zero when there is no current applied to the stator armature. The spring can, for example, be a coil compression spring overfitting a portion of the shaft or a spiral torsion spring extending between the rotor and the stator armature.
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