| abstract |
In a hydrodynamic bearing using a sleeve made of sintered metal, if the surface pores are present above a certain level, the generated pressure leaks, the rigidity is lowered, and there is a case where contact wear occurs due to a load and breaks down. Radial bearing rigidity is achieved by setting the porosity of the surface of the sleeve within a certain range and keeping the ridge width of the dynamic pressure groove above a certain value, thereby preventing and preventing the leakage of the dynamic pressure generated pressure. The conventional cover can be eliminated, and the linear expansion coefficient of the shaft and the sleeve is made of iron-based metal particles as the raw material for the sleeve made of sintered metal so that the shaft is larger. By doing so, it is possible to obtain a hydrodynamic bearing device in which the performance of the bearing at a low temperature is good. [Selection] Figure 1 |