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Seal For Fluid Dynamic Bearing Spindle Motor Disclosure Number: IPCOM000015738D
Original Publication Date: 2002-Sep-26
Included in the Prior Art Database: 2003-Jun-21

Publishing Venue



Non operational vibration tests of the present Fluid Dynamic Bearing (FDB) spindle motor design cause oil to leak from the motor. The figure below shows expanded views of the bearing sleeve, thrust plate and top seal. During non-op vibration, oil is splashed upward toward the top seal. For the present design (right side of Figure), there is a tight gap between the thrust plate and sleeve and oil becomes momentarily trapped in this gap. Before the oil can return to the bearing, additional oil is splashed upward as a result of the non-op vibration test. After extended vibration, oil is pushed out of the motor. The disclosed designs eliminate the tight gap between the thrust plate and sleeve and provide a large chamber for the splashed oil to reside in until it returns to the bearing. A tight labyrinth seal with barrier film is provided to prevent leakage outside the spindle motor due to oil migration. This design requires oil to return to the bearing as a result of surface tension. The second figure shows an alternate design, in which the features of the labyrinth seal are sloped, using centrifugal force to help the oil return to the bearing. Shaft