Patent ID: 7635936
Filing Date: 2009-12-22
Classification: F16C,G11B,H02K

Abstract:
1. A fluid dynamic pressure bearing comprising: a shaft centered on a center axis; a stationary portion having a bearing hole into which the shaft is inserted and being arranged to support the shaft in a rotatable manner about the center axis; a radial gap located between opposing surfaces of the shaft and the stationary portion; a lubricating oil arranged to fill the radial gap; a first seal portion, at least partially in the form of an axially extending space, arranged within the stationary portion outside the radial gap in a radial direction that is substantially perpendicular to the center axis and connected to the radial gap; a second seal portion, at least partially in the form of an axially extending space, arranged at an upper end of the radial gap and connected to the radial gap and the first seal portion; and a radial fluid dynamic pressure bearing located in a first gap as a portion of the radial gap and having a plurality of dynamic pressure generation grooves arranged to generate a dynamic pressure of the lubricating oil during rotation of the shaft; wherein an axial length of the first seal portion is longer than that of the second seal portion.