Hydrodynamic bearing and seal

摘要

The hydrodynamic bearing unit has a shaft, a sleeve rotatably disposed over the shaft and defining spaced-apart hydrodynamic journal bearings and an annular axial thrust plate secured to the shaft to form a shaft sub-assembly having a first radial surface in facing confrontation with a shoulder of the sleeve and defining a first hydrodynamic thrust bearing. A thrust bushing is secured to the sleeve to form a sleeve sub-assembly having a bearing surface in overlying facing engagement with a second radial surface of the annular axial thrust plate to form a second hydrodynamic thrust bearing. A seal for hydrodynamic lubricant is defined within an annular V-groove located adjacent to the shaft having an apex converging toward the second hydrodynamic thrust bearing. A motor rotates the sleeve sub-assembly relative to the shaft sub-assembly. Hydrodynamic lubricant within the annular V-groove is retained in place by capillary force in the absence of rotation and by centrifugal force in the presence of relative rotation between the sub-assemblies.