| 摘要 |
An improved magnetic liquid seal assembly (10) including an inner magnetic ring (18) concentrically bonded to the shaft (12), an outer magnetic ring (20) concentrically surrounding the inner magnetic ring (18) with a uniform air gap (22) therebetween and a quantity of magnetic fluid (24) disposed about the air gap (22) such that there is no passage of air or debris through the air gap (22). The inner and outer magnetic rings (18 and 20) are permanently magnetized units while the magnetic fluid (24) is a suspension of permanently magnetized particles in a carrier fluid. The direction of polarization in both the inner and outer magnetic rings (18 and 20) is parallel to the axis of the shaft (12), but is opposite in the two rings, at least in the vicinity of the air gap (22). In the preferred embodiment, the magnetic rings (18 and 20) are provided with iron pole pieces (26) on the planar surfaces to intensify the field strength. Furthermore, both the inner and outer magnetic rings (18 and 20) are provided with surface magnetizations in the nature of guard rings (28 and 30) which prevent the magnetic fluid (24) from migrating along the surface of the pole piece (26) to either the shaft (12) or the housing (16). The primary use of the improved seal (10) is in disk drive assemblies in the data processing and computer peripheral industries. |
