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: 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: 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).