Abstract: A method includes compacting metal powder including at least not less than 70% by weight of particles with diameters of not more than 45 ?m 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.

Abstract: The present invention is a method for producing a fluid dynamic pressure bearing made of powder sintered metal and that grooves for generating dynamic pressure are formed on an inner peripheral surface and whose object is to facilitate forming a ferrosoferric oxide (Fe3O4) membrane on a surface of a bearing material, the method comprising compacting metal powder including at least not less than 70% by weight of particles with diameters of not more than 45 ?m to gain a bearing material, sintering said bearing material, forming grooves for generating dynamic pressure on said sintered bearing material, and performing steam treatment to said sintered bearing material with said 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, so that 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 s

Abstract: A heat reversible gel-like lubricating composition having such properties that, in a service bulk temperature region, the composition is in a semi-solid gel form as with grease, but in a local high-temperature region such as a sliding contact site, the composition is homogeneously melted, is free from grease, i.e., the precipitation of foreign materials, exhibits excellent low frictional characteristics unrealizable by grease, and exhibits significant energy saving properties. The heat reversible gel-like lubricating composition includes a mineral oil and/or synthetic liquid lubricating base oil and a bisamide and/or a monoamide and has heat reversible gel properties. Preferably, the heat reversible gel-like lubricating composition contains a triamide and further contains, based on 100 parts by weight of the liquid lubricating base oil, 0.01 to 500 parts by weight in total of a bisamide and a monoamide and 0.05 to 10 parts by weight of a friction regulator.