FLUID DYNAMIC PRESSURE BEARING DEVICE AND METHOD OF PRODUCING THE SAME

摘要

A fluid dynamic pressure bearing device that achieves high rigidity against moment without a reduction in assembly accuracy and bearing performance. In the bearing device, bearing sleeves are arranged in the axial direction and coaxiality of radial bearing surfaces formed on the inner peripheral surfaces of the bearing sleeves is set to 3 µm or less. This secures width accuracy between the radial bearing gaps to prevent a reduction in bearing performance and a failure such as wear etc. caused by contact between a shaft member and the bearing sleeves. Further, a first radial bearing surface and a second radial bearing surface are provided on at least one sleeve, and this allows a sleeve assembly constructed from bearing sleeves to be supported at least three positions in the axial direction in a process of assembling the sleeve assembly. As a result, assembly work can be carried out with two bearing sleeves prevented from being bent in the middle and highly accurate coaxiality between both bearing sleeves secured.