| 摘要 |
A solenoid device adapted for use with an automobile door locking device, for example, comprises a shaft, two magnetic cores, a permanent magnet sandwiched between the cores, two field coils for producing a magnetic flux along the shaft, a magnetic yoke body for forming a magnetic flux path along the outsides of the coils, a magnetic center plate disposed between the coils, and two magnetic yoke end plates. The permanent magnet and the cores are fixed to the shaft to form a magnetic plunger. The center plate includes an annular magnetic flux path portion through which the magnetic plunger extends. The width A of the annular magnetic path portion in the direction of the axis of the shaft, the distance B between the end surfaces of the magnetic flux path portion and the respective end surfaces of the yoke end plates, the thickness C of the permanent magnet in the direction of polarization, and the length D of the magnetic cores in the direction of the axis of the shaft are so selected as to satisfy the following relations: A>C and D>/=B.
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