Patent ID: 9476449
Filing Date: 2016-10-25
CPC Classification: F16C

Claim Text:
1. A fluid dynamic bearing device, comprising: a housing formed into a bottomed cylindrical shape so as to have one open axial end and another closed axial end; a bearing sleeve fixed to an inner periphery of the housing; a shaft member removably inserted along an inner periphery of the bearing sleeve; an annular member having an inner peripheral surface for defining a radial gap together with an outer peripheral surface of the shaft member, the annular member being fixed to an inner periphery of the one open axial end of the housing in a state of engaging with the bearing sleeve in an axial direction; a radial bearing portion for supporting the shaft member in a radial direction by an oil film of lubricating oil, which is formed in a radial bearing gap defined between an inner peripheral surface of the bearing sleeve and the outer peripheral surface of the shaft member; a thrust bearing portion for supporting the shaft member in a thrust direction; and a bottom gap having the thrust bearing portion received therein, and being filled with the lubricating oil, wherein the housing has a void section formed in an interior space thereof, the void section not being filled with the lubricating oil, wherein assuming that d wherein, in a standing position state where the one open axial end of the housing is arranged at an upper side in a vertical direction and the another closed axial end of the housing is arranged at a lower side in the vertical direction, an oil level of the lubricating oil is maintained in an annular space that is defined between an inner circumferential chamfer which arranged at one axial end of the bearing sleeve and the outer peripheral surface of the shaft member.