| 摘要 |
<p>PURPOSE:To set the number of directions of attracting a shaft larger than the number of magnetic poles by forming three or more magnetic poles on a common fixed iron core, and applying an electric current to two adjacent exciting coils positioned on both sides in the direction of attracting a shaft. CONSTITUTION:Magnetic poles 4a-4d projected toward a shaft 2 are formed on a common fixed iron core 3, and exciting coils 6a-6d are respectively wound round the magnetic poles 4a-4d. When an electric current is applied to the exciting coil 6a or 6c, the polarity of the magnetic pole 4a or 4c is N-pole, and when an electric current is applied to the exciting coil 6b or 6d, the polarity of the magnetic pole 4b or 4d is S-ople. That is, the exciting coils are arranged in such a manner that every adjacent magnetic pole is different in polarity. Accordingly, if there are four directions of attracting the shaft, the number of magnetic poles is four, which is the same as the number of attracting directions. Thus, the half of the magnetic poles in the prior art is enough so as to reduce apparatus to a compact size.</p> |
