| 摘要 |
A solenoid actuator comprising a coil or coils of electrical wire and a plugnut and movable core within the coil(s). A magnetic yoke surrounds the coil(s), the axis of the latter extending across the magnetic circuit defined by the yoke. Relatively large and small permanent magnets are associated with the yoke on opposite sides of the axis, the magnets producing flux in opposite directions. A flux sensor, closer to the small magnet, senses changes in direction of the flux. When the core and plugnut are separated, the large magnet flux predominates throughout the yoke. When the core engages the plugnut, the small magnet flux predominates in its portion of the yoke, this change in flux direction being detected by the sensor. Thus, the sensor can be used to indicate the position of the core with respect to the plugnut.
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