| 摘要 |
PROBLEM TO BE SOLVED: To surely prevent the leakage of a lubricating fluid outside at a low cost. SOLUTION: In this device, a magnetic fluid 8 is used as a lubricating fluid, for causing dynamic pressure action to a dynamic pressure bearing part 7; and the magnetic fluid 8 is constituted so that it can be retained by magnetic force, by a sealing annular magnet force, by a sealing annular magnet 13 provided on an outside opened side than the bearing part 7, and by capillary force, by a capillary sealing part constituted between the magnet 13 and a member 6 facing it, and the magnetic fluid 8 can be surely retained by a sealing part of relatively simple constitution having dual force doubling the magnetic force and capillary force; and also the magnet 13 is consisting of an Nd-Fe-B magnet or a nano-crystal Nd-Fe-B magnet, containing Nd, Fe, and B and having various proper characteristics such as a high residual magnetic flux density, proper magnetization in a low magnetic field, a low cost, and facility and adaptability for various kinds of moldings. |
