Abstract: Disclosed herein is a method of manufacturing a hydrodynamic bearing in which a metal bearing made of sintered metal powder is internally subjected to chemical etching, to form hydrodynamic pressure grooves thereon, thus assuring a high-precision and reliable hydrodynamic bearing. The method includes: compressing metal powder that is a raw material of the bearing in a press unit, and sintering the compressed metal powder at a predetermined temperature, thus preparing a sintered bearing; removing foreign substances adhering to the sintered bearing through a deburring process, and pressing the sintered bearing into a desired shape; forming a hydrodynamic groove, configured to generate hydrodynamic pressure, on an internal surface of the shaped bearing using chemical etching; and conducting a post treatment of cleaning the bearing including the hydrodynamic grooves thereon and drying the bearing.

Abstract: A linear vibration motor comprising a movable unit, a base assembly having a coil assembly, a housing and an elastic member, in which the movable unit has the maximum mass from a fixed housing volume. The elastic member has the outer periphery fixed to the ceiling of the housing and the inner periphery fixed to the top of the movable unit opposed to the outer periphery. The elastic member is deformable to the extent that the outer and inner peripheries are shift to a coplanar position from a parallel position where they are spaced for a predetermined distance from each other. The core assembly is distanced downward from the movable unit or a predetermined gap.