High pressure barrier to oil loss by diffusion

A fluid dynamic bearing defined by an interface of a hub and a sleeve, the hub comprising a shaft portion configured to rotate within the sleeve and a body portion configured to rotate above the sleeve, the bearing comprising:

• a gap region between the hub and the sleeve;
• a capillary seal within the gap;
• a volume of lubricating fluid within the gap;
• and
• an air pumping groove pattern disposed in the gap, the air pumping groove pattern forming a high air pressure region in the gap when the shaft portion of the hub is rotated within the sleeve.

A spindle motor of a disc drive, the spindle motor comprising a sleeve and a hub rotating relative to the sleeve, the hub having a shaft portion configured to rotate within the sleeve and a body portion configured to rotate above the sleeve, and the spindle motor having a bearing surface defined by the interface of the hub and the sleeve, wherein the bearing surface comprises:

• a gap region between the hub and the sleeve;
• a capillary seal within the gap;
• a volume of lubricating fluid within the gap;
• and
• an air pumping groove pattern disposed in the gap, the air pumping groove pattern forming a high air pressure region in the gap when the shaft portion of the hub is rotated within the sleeve.

A disc drive storage system, comprising:

• a disc,
• a head moveable over the disc,
• a spindle motor,
• the spindle motor comprising a sleeve and a hub rotating relative to the sleeve, the hub having a shaft portion configured to rotate within the sleeve and a body portion configured to rotate above the sleeve, the hub configured to receive and support the disc, and the spindle motor having a bearing surface defined by the interface of the hub and the sleeve, wherein the bearing surface comprises:
• a gap region between the hub and the sleeve;
• a capillary seal within the gap;
• a volume of lubricating fluid within the gap;
• and
• an air pumping groove pattern disposed in the gap, the air pumping groove pattern forming a high air pressure region in the gap when the shaft portion of the hub is rotated within the sleeve.