Abstract: A sintered bearing is made of a sintered compact containing nickel silver (Cu—Ni—Zn) as a base. In the sintered bearing, P is not added in the sintered compact. Alternatively, a content of P in the sintered compact is less than 0.05 mass % in terms of mass ratio to a total mass. Consequently, crystal grains constituting the sintered compact can be micronized. In particular, in the sintered bearing, an average crystal particle diameter of the crystal grains constituting the sintered compact is 20 ?m or less. Consequently, the mechanical strength and the vibration resisting properties can be improved, and the rotation shaft can be prevented from being damaged.

Abstract: A sintered bearing is made of a sintered compact containing nickel silver (Cu—Ni—Zn) as a base. In the sintered bearing, P is not added in the sintered compact. Alternatively, a content of P in the sintered compact is less than 0.05 mass % in terms of mass ratio to a total mass. Consequently, crystal grains constituting the sintered compact can be micronized. In particular, in the sintered bearing, an average crystal particle diameter of the crystal grains constituting the sintered compact is 20 ?m or less. Consequently, the mechanical strength and the vibration resisting properties can be improved, and the rotation shaft can be prevented from being damaged.

Abstract: A method for manufacturing a wick includes: supplying material powder containing metal powder onto a base; heating the material powder on the base to obtain a sintered compact; and rolling the sintered compact. In this situation, when the material powder supplied onto the base is heated to form the sintered compact, the sheet-shaped sintered compact can be formed. Further, when the sintered compact is rolled, a void ratio of the sintered compact can be controlled after forming the sintered compact, thereby controlling the capillarity of the wick.

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