Abstract: An internal pore of a sintered metal bearing 8 is impregnated with a lubricating fluid, and a radial dynamic pressure generation portion 8a1 is formed on an inner peripheral surface 8a. An axial dimension L is 4.8 nm or less, a thickness dimension t is 0.5 mm or more and 1.5 nm or less, and a ratio L/D2 of the axial dimension L to an outer diameter dimension D2 is 0.24 or more and 0.6 or less.

Abstract: Provided is a slide bearing (bearing sleeve (8)), comprising an oxidized green compact in which particles (11) of metal powder are bonded to each other by an oxide film (12) formed on surfaces of the particles (11). The oxidized green compact has a bearing surface (A, B) configured to slide, through intermediation of a lubricating film, relative to a mating member (shaft member (2)) to be supported. The bearing surface (A, B) has a large number of opening portions (13a), and the large number of opening portions (13a) and inner pores (13b) are interrupted in communication therebetween by the oxide film (12).

Abstract: Provided is a spherical aluminum nitride powder having a particle shape that is closer to sphericity. The spherical aluminum nitride powder according to the present invention, which contains a main component comprising AlN and a side component comprising a rare earth compound, is characterized in that at least 70% of particles in the powder have an outer peripheral shape having neither an angular edge part nor an uneven part in the plane projection image of individual particles.

Abstract: Provided is a slide bearing (bearing sleeve (8)), comprising an oxidized green compact in which particles (11) of metal powder are bonded to each other by an oxide film (12) formed on surfaces of the particles (11). The oxidized green compact has a bearing surface (A, B) configured to slide, through intermediation of a lubricating film, relative to a mating member (shaft member (2)) to be supported. The bearing surface (A, B) has a large number of opening portions (13a), and the large number of opening portions (13a) and inner pores (13b) are interrupted in communication therebetween by the oxide film (12).

Abstract: Provided is a spherical aluminum nitride powder having a particle shape that is closer to sphericity. The spherical aluminum nitride powder according to the present invention, which contains a main component comprising AlN and a side component comprising a rare earth compound, is characterized in that at least 70% of particles in the powder have an outer peripheral shape having neither an angular edge part nor an uneven part in the plane projection image of individual particles.

Abstract: A sintered bearing (1) of the present invention includes: an inner layer (2) and an outer layer (3) each made of sintered metal and formed into a cylindrical shape; and a radial dynamic pressure generating portion (dynamic pressure grooves 1a1 and 1a2) die-formed in an inner peripheral surface of the inner layer (2), in which the outer layer (3) has compressive yield strength higher than compressive yield strength of the inner layer (2).

Abstract: Provided is a fluid dynamic bearing device (1), including: a bearing sleeve (8) made of sintered metal; a rotary member (2) including a shaft portion (21) and a hub portion (23); and first and second thrust bearing portions (T1, T2) that form thrust bearing gaps respectively on an upper end surface (8b) and a lower end surface (8c) of the bearing sleeve (8) along with rotation of the rotary member (2). At least an outer peripheral surface of the bearing sleeve (8) is subjected to pore sealing treatment. A sealing gap (S) for retaining an oil surface of lubricating oil is made along a tapered outer peripheral surface (8d1) of the bearing sleeve (8). A lid member (10) having a bottomed cylindrical shape being fixed to an outer periphery of a lower end of the bearing sleeve (8).

Abstract: A sintered bearing includes a sintered metal formed by using a metal powder mixture containing copper powder and iron powder. The metal powder mixture contains 80 wt % or more of particles having an average particle diameter of less than 45 ?m. The copper powder contains electrolytic copper powder. The electrolytic copper powder contains 40 number % or more of particles having a circularity of 0.64 or more.

Abstract: A sintered bearing (1) of the present invention includes: an inner layer (2) and an outer layer (3) each made of sintered metal and formed into a cylindrical shape; and a radial dynamic pressure generating portion (dynamic pressure grooves 1a1 and 1a2) die-formed in an inner peripheral surface of the inner layer (2), in which the outer layer (3) has compressive yield strength higher than compressive yield strength of the inner layer (2).

Abstract: Provided is a fluid dynamic bearing device (1), including: a bearing sleeve (8) made of sintered metal; a rotary member (2) including a shaft portion (21) and a hub portion (23); and first and second thrust bearing portions (T1, T2) that form thrust bearing gaps respectively on an upper end surface (8b) and a lower end surface (8c) of the bearing sleeve (8) along with rotation of the rotary member (2). At least an outer peripheral surface of the bearing sleeve (8) is subjected to pore sealing treatment. A sealing gap (S) for retaining an oil surface of lubricating oil is made along a tapered outer peripheral surface (8d1) of the bearing sleeve (8). A lid member (10) having a bottomed cylindrical shape being fixed to an outer periphery of a lower end of the bearing sleeve (8).

Abstract: A sintered bearing includes a sintered metal formed by using a metal powder mixture containing copper powder and iron powder. The metal powder mixture contains 80 wt % or more of particles having an average particle diameter of less than 45 ?m. The copper powder contains electrolytic copper powder. The electrolytic copper powder contains 40 number % or more of particles having a circularity of 0.64 or more.

Abstract: A maximum diameter (d) of each of surface openings formed in a bearing surface through melting of Sn metal powder as a binder is set within a range of 0 ?m<d?25 ?m. In order to attain the range, binder metal powder having a maximum particle diameter of 25 ?m or less is used.

Abstract: With use of a fine copper-based powder, specifically a copper-based powder that contains particles each having a diameter of 45 ?m or less by 80 weight % or more, an air permeability can be significantly reduced. When this copper-based powder is used, a sintered metal can be easily formed to contain copper by 40% or less (contain iron by 60% or more) to enhance abrasion resistance, and to have an oil permeability of 1.00 g/10 min or less to increase an oil film formation rate.

Abstract: A sintered metal bearing is obtained by compression-molding of a raw-material powder containing at least a Cu powder, an SUS powder, and a pure Fe powder and thereafter sintering a compression-molded body at a predetermined temperature.

Abstract: Provided is a sintered metal bearing, which is formed of raw material powder containing copper-based powder and iron-based powder as main components, the sintered metal bearing including a radial bearing surface along an inner periphery thereof. The copper-based powder includes fine copper powder exhibiting a particle size distribution in which a ratio of particles with a diameter of less than 45 ?m is 80 wt % or more, the fine copper powder occupying one-third or more of a whole of the copper-based powder in terms of a weight ratio. A compressed body formed by compressing the raw material powder is sintered at 900° C. or more to 1,000° C. or less.

Abstract: A sintered metal bearing member is provided that includes radial bearing surfaces arranged at two regions spaced apart from each other in an axial direction on an inner peripheral surface. The bearing member includes radial dynamic pressure generating portions in contact with the radial bearing surfaces. The radial dynamic pressure generating portions are formed on the radial bearing surfaces. The bearing member includes a thrust bearing surface arranged on at least one of the end surfaces and a thrust dynamic pressure generating portion for generating a dynamic pressure in the lubricating oil in contact with the thrust bearing surface. The thrust dynamic pressure generating portion is formed on the thrust bearing surface. The bearing member includes a middle relief portion arranged between the radial bearing surfaces in the axial direction. The middle relief portion has a larger diameter than the radial bearing surfaces.

Abstract: With use of a fine copper-based powder, specifically a copper-based powder that contains particles each having a diameter of 45 ?m or less by 80 weight % or more, an air permeability can be significantly reduced. When this copper-based powder is used, a sintered metal can be easily formed to contain copper by 40% or less (contain iron by 60% or more) to enhance abrasion resistance, and to have an oil permeability of 1.00 g/10 min or less to increase an oil film formation rate.

Abstract: When a bearing member (bearing sleeve (8)) is formed of a sintered metal comprising a middle relief portion (E), a lubricating oil can be impregnated and retained in inner pores of the sintered metal. Thus, when the lubricating oil in a middle relief space (E0) is drawn into a radial bearing gap side and lubricating oil pressure in the middle relief space (E0) decreases, the lubricating oil impregnated in the inner pores of the bearing sleeve (8) is drawn out from surface pores of the middle relief portion (E) and supplied into the middle relief space (E0). Thus, generation of negative pressure is prevented.

Abstract: The present invention aims to achieve a reduction in cost for a fluid dynamic bearing device. The fluid dynamic bearing device supports a shaft member (2) radially in a non-contact fashion by a dynamic pressure action generated in a radial bearing gap between an outer peripheral surface of the shaft member (2) and an inner peripheral surface (7a) of a bearing member (7), and is composed of the shaft member (2), the bearing member (7), a cover member (8), and a seal member (9). The shaft member (2) is inserted into an inner periphery of the bearing member (7), and an opening at a lower end thereof is sealed by the cover member (8). The seal member (9) is attached to an opening at an upper end of the bearing member (7), forming a seal space (S) between itself and the outer peripheral surface of the shaft member (2). Dynamic pressure grooves (G) of radial bearing portions (R1 and R2) are formed in an inner peripheral surface (7a) of the bearing member (7) by molding.

Abstract: A density of a bearing sleeve made of a sintered metal is set within a range of from 80% to 95% with respect to a true density, and a Young's modulus of the bearing sleeve is set to be equal to or more than 70 GPa. When the density of the bearing sleeve is increased and also the Young's modulus thereof is set to be equal to or more than 70 GPa in this manner, dimensional variation of an inner peripheral surface of the bearing sleeve can be suppressed to be equal to or less than 0.5 ?m when a shaft member having an outer diameter of from 2 mm to 4 mm is to be supported.