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 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: A shaft member for a fluid bearing device includes, on an outer peripheral surface thereof, two bearing surfaces (31 and 32) separated from each other in an axial direction, and a middle relief portion (33) formed between the bearing surfaces (31 and 32) and having a diameter smaller than a diameter of the bearing surfaces. The middle relief portion (33) includes a cylindrical surface portion (331) having a ground surface, and stepped portions (332) arranged on both axial sides of the cylindrical surface portion and having a diameter difference from the cylindrical surface portion.

Abstract: A shaft member for a fluid bearing device includes, on an outer peripheral surface thereof, two bearing surfaces (31 and 32) separated from each other in an axial direction, and a middle relief portion (33) formed between the bearing surfaces (31 and 32) and having a diameter smaller than a diameter of the bearing surfaces. The middle relief portion (33) includes a cylindrical surface portion (331) having a ground surface, and stepped portions (332) arranged on both axial sides of the cylindrical surface portion and having a diameter difference from the cylindrical surface portion.

Abstract: Dynamic pressure bearing (10), including: a green compact (10?), as a base material, of raw material powder including metal powder capable of forming an oxide coating; and dynamic pressure generating portions (A1 and A2) formed through die molding on an inner peripheral surface (8a) forming a radial bearing gap with an outer peripheral surface (2a1) of a shaft to be supported, that is, a shaft member (2). An oxide coating (11) is formed between particles of the metal powder by subjecting the green compact (10?) to steam treatment, and the dynamic pressure bearing (10) has a radial crushing strength of 150 MPa or more.

Abstract: A ratio W1/W2 of a circumferential width W1 of each of inclined hill portions G2 of a radial dynamic pressure generating portion G and a circumferential width W2 of each of inclined groove portions G3 is 1.2 or larger. And when an inner diameter of a bearing member is D, the circumferential width W2 of each of the inclined groove portions satisfies 0.2D?W2?0.4D.

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: Provided is a fluid dynamic bearing device (1) including a rotary body (2A), a bearing member (22) (sleeve portion) made of a sintered metal arranged on the rotary body (2A), having end surfaces (22b, 22c), a thrust bearing gap formed by a lower end surface (22c) of the bearing member (22), filled with lubricating oil (11), and a thrust dynamic pressure generating portion (B). A dynamic pressure generating action is caused in the lubricating oil in the thrust bearing gap along with rotation of the rotary body (2A) to support the rotary body (2A) in one thrust direction in a non-contact manner. The bearing member (22) has an oil permeability of 4% or more with respect to a mass flow rate of the lubricating oil (11) flowing along the thrust dynamic pressure generating portion (B) during the rotation of the rotary body (2A).

Abstract: Dynamic pressure bearing (10), including: a green compact (10?), as a base material, of raw material powder including metal powder capable of forming an oxide coating; and dynamic pressure generating portions (A1 and A2) formed through die molding on an inner peripheral surface (8a) forming a radial bearing gap with an outer peripheral surface (2a1) of a shaft to be supported, that is, a shaft member (2). An oxide coating (11) is formed between particles of the metal powder by subjecting the green compact (10?) to steam treatment, and the dynamic pressure bearing (10) has a radial crushing strength of 150 MPa or more.

Abstract: A ratio W1/W2 of a circumferential width W1 of each of inclined hill portions G2 of a radial dynamic pressure generating portion G and a circumferential width W2 of each of inclined groove portions G3 is 1.2 or larger. And when an inner diameter of a bearing member is D, the circumferential width W2 of each of the inclined groove portions satisfies 0.2D?W2?0.4D.

Abstract: Provided is a sintered bearing (8) having a plurality of axial grooves (8c1) equiangularly arranged in an outer peripheral surface (8c) thereof and a plurality of dynamic pressure generating grooves (8a11) equiangularly arranged in an inner peripheral surface (8a) thereof, in which a number of the plurality of axial grooves (8c1) is an integral multiple of a number of the plurality of dynamic pressure generating grooves (8a11) on the same circumference.

Abstract: A fluid dynamic bearing device including: a bearing sleeve fixed to an inner periphery of a housing; a shaft member removably inserted along an inner periphery of the bearing sleeve; an annular member having an inner peripheral surface for defining a radial gap together with an outer peripheral surface of the shaft member; and radial bearing portions and a thrust bearing portion for supporting the shaft member. At least the radial bearing gap at each of the radial bearing portions, and a bottom gap having the thrust bearing portion received therein are filled with lubricating oil. A void section is formed in an interior space of the housing. Assuming that d1 represents a gap width of the radial bearing gap and d2 represents a gap width of the radial gap, a relationship of 30d1?d2?250d1 is satisfied.

Abstract: A fluid dynamic bearing device (1), including: a bearing member (22) on a rotary side; a housing (7) on a stationary side; a sealing member (9); a radial bearing gap to be formed between an outer peripheral surface (22a) of the bearing member (22) and an inner peripheral surface (7a2) of the housing (7); and a thrust bearing gap to be formed between a lower end surface (22c) of the bearing member (22) and an inner bottom surface (7b1) of the housing (7). The radial bearing gap and the thrust bearing gap are filled with lubricating oil (11). An axial gap (10) containing air is formed between an upper end surface (22b) of the bearing member (22) and a lower end surface (9b) of the sealing member (9), which faces the upper end surface (22b) of the bearing member (22).

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: Provided is a fluid dynamic bearing device (1) including a rotary body (2A), a bearing member (22) (sleeve portion) made of a sintered metal arranged on the rotary body (2A), having end surfaces (22b, 22c), a thrust bearing gap formed by a lower end surface (22c) of the bearing member (22), filled with lubricating oil (11), and a thrust dynamic pressure generating portion (B). A dynamic pressure generating action is caused in the lubricating oil in the thrust bearing gap along with rotation of the rotary body (2A) to support the rotary body (2A) in one thrust direction in a non-contact manner. The bearing member (22) has an oil permeability of 4% or more with respect to a mass flow rate of the lubricating oil (11) flowing along the thrust dynamic pressure generating portion (B) during the rotation of the rotary body (2A).

Abstract: A fluid dynamic bearing device (21) includes: a shaft member (22); a housing (29) as an outer member which is arranged on a radially outer side of the shaft member (22) and is opened at both ends; a radial bearing gap which is formed on a radially inner side of the housing (29) and faces an outer peripheral surface of the shaft member (22); and a lid member (30) closing an opening on one end side of the housing (29), wherein the lid member (30) is fitted to an outer peripheral surface of the housing (29) with a fastening allowance which does not affect accuracy of a surface defining an outer diameter dimension of the radial bearing gap so that the housing (29) and the lid member (30) are bonded and fixed to each other.

Abstract: Providing a fluid dynamic bearing device, wherein the outer member comprises a member formed by a pressing process on a plate member, the radial bearing surface and at least the one of the thrust bearing surfaces of the outer member being formed by the pressing process, and wherein at least a part of the inner member, which forms the radial bearing surface and the thrust bearing surfaces of the inner member, is made of a sintered metal.

Abstract: A fluid dynamic bearing device including: a bearing sleeve fixed to an inner periphery of a housing; a shaft member removably inserted along an inner periphery of the bearing sleeve; an annular member having an inner peripheral surface for defining a radial gap together with an outer peripheral surface of the shaft member; and radial bearing portions and a thrust bearing portion for supporting the shaft member. At least the radial bearing gap at each of the radial bearing portions, and a bottom gap having the thrust bearing portion received therein are filled with lubricating oil. A void section is formed in an interior space of the housing. Assuming that d1 represents a gap width of the radial bearing gap and d2 represents a gap width of the radial gap, a relationship of 30d1?d2?250d1 is satisfied.

Abstract: A fluid dynamic bearing device (1), including: a bearing member (22) on a rotary side; a housing (7) on a stationary side; a sealing member (9); a radial bearing gap to be formed between an outer peripheral surface (22a) of the bearing member (22) and an inner peripheral surface (7a2) of the housing (7); and a thrust bearing gap to be formed between a lower end surface (22c) of the bearing member (22) and an inner bottom surface (7b1) of the housing (7). The radial bearing gap and the thrust bearing gap are filled with lubricating oil (11). An axial gap (10) containing air is formed between an upper end surface (22b) of the bearing member (22) and a lower end surface (9b) of the sealing member (9), which faces the upper end surface (22b) of the bearing member (22).

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.