US Patent 7866046 Method for manufacturing hydrodynamic bearing and shaft

A method for manufacturing a hydrodynamic bearing (30) includes the following steps. First, a substrate having a surface with multiple protrusions thereon is formed. The protrusions are adapted for forming grooves in a preform. The preform, when finally processed, becomes a shaft of the hydrodynamic bearing or a bearing of the hydrodynamic bearing. Second, a feedstock of binder and powder is pushed to the surface of the substrate to form the perform on the surface of the substrate. Third, the substrate is removed from the preform. Fourth, the preform is sintered. Fifth, the preform is precision machined to obtain the shaft or the bearing, as the case may be. In the shaft or bearing, the grooves are for generating hydrodynamic pressure.