| 摘要 |
PURPOSE: To constantly surely hold magnetic fluid in a seal gap by disposing a magnetic pole piece between two permanent magnets of which the magnetic poles of the same polarity face each other, and disposing inner circumferential surfaces of the permanent magnets at a constant interval from a shaft for forming two circular spaces between them and the shaft on both sides of an intermediate circular gap. CONSTITUTION: A magnetic pole piece 3 is disposed between two annular permanent magnets 1, 2, magnetic poles of the same polarity of the permanent magnets 1, 2 are set to face each other, and inner circumferential surfaces of the two permanent magnets 1, 2 are disposed at a constant interval from a shaft 4 for forming two circular spaces between them and the shaft 4 on both sides of an intermediate circular gap 5 formed between the magnetic pole piece 3 and the shaft 4. Magnetic fields generated by the two permanent magnets 1, 2 are thus concentrated toward the shaft 4, and gradient of a magnetic flux is directed toward a center of the magnetic pole piece 3, thereby magnetic fluid 6 in the gap 5 can be securely held. |
