| 摘要 |
A fluid dynamic bearing mechanism (1) that can ensure bearing rigidity, reduce shaft loss torque, reduce power consumption, stabilize axial rotation, and improve rotational accuracy is disclosed. The fluid dynamic bearing mechanism (1) is suitable for use in a hard disk drive. In the fluid dynamic bearing mechanism (equipped with a bearing case (10) endplate (20), and shaft (30)) a cylindrical hole (11) of the bearing case is stepped cylindrical hole that has a large diameter part (11a) and a small diameter part (11b). The shaft is stepped shaft that has a large diameter part (31a) and a small diameter part (31b). On the outer circumference of either the large diameter part of the stepped cylindrical hole, or the large diameter part of the stepped shaft, a first dynamic pressure groove (51) is formed. On the outer circumference of either the small diameter part of the stepped cylindrical hole or the small diameter part of the stepped shaft, a second dynamic pressure groove (52) is formed. On the surface of a step part of the stepped cylindrical hole, the third dynamic pressure groove (53) is formed. The small gaps that face each of the three dynamic pressure grooves are filled with a dynamic pressure generating lubricating oil. |
