Straight advancing die magnetic fluid shaft seal device

摘要

PURPOSE: To apply a magnetic fluid shaft sealing device, which can securely maintain the clean gaseous atmosphere without dust and have a long lifetime, to a straight moving shaft. ;CONSTITUTION: A magnetic fluid shaft sealing device comprises an annular uneven portion 7 formed at the outer peripheral surface of a straight moving shaft 6 disposed across an atmospheric region P and a low pressure region Q, an annular pole piece 2 disposed opposite to the annular uneven portion 7 and having another annular uneven portion 8, a magnet 9 for forming a magnetic path between the pole piece 2 and the straight moving shaft 6, and magnetic fluid to be injected between the pole piece 2 and the straight moving shaft 6. An axial pitch of the annular uneven portion 7 on the straight moving shaft 6 is made to be different from that of the annular uneven portion 8 on the pole piece 2 so that either one of pairs of projections of the uneven portions 7, 8 is always disposed oppositely even if the straight moving shaft 6 is moved in the arrow A-A' direction in a straightly reciprocating manner.;COPYRIGHT: (C)1995,JPO