Method for producing fluid dynamic pressure bearing

摘要

A method includes compacting metal powder including at least not less than 70% by weight of particles with diameters of not more than 45 μm to obtain a bearing material, sintering the bearing material, forming grooves for generating dynamic pressure on the sintered bearing material, and performing steam treatment to the sintered bearing material with the grooves to form a ferrosoferric oxide (Fe3O4) membrane on a porous surface of an inner surface or on porous surfaces of an inner surface and both end surfaces. Thus, gaps between particles become small because diameters of the particles of material powder of a powder sintered bearing material are approximately even and fine and are even small pores. As a result, sealing pores on the surface due to steam treatment is easy, and dynamic pressure cannot be leaked.

主权项

1. A method of producing a fluid dynamic pressure bearing made of powder sintered metal having grooves for generating dynamic pressure on an inner peripheral surface of the bearing, said method comprising:
compacting metal powder including not less than 70% by weight of particles with diameters of not more than 45 μm so as to form a bearing material, the cumulative 50% diameters (D50) of the particles of the metal powder being within a range of 20 μm to 60 μm as measured by a laser beam diffraction system particle size analyzer; sintering the bearing material; forming grooves on the sintered bearing material for generating dynamic pressure; and performing steam treatment on the sintered bearing material having the grooves so as to form a ferrosoferric oxide (Fe3O4) membrane on a porous surface of an inner surface of the bearing material.