Patent ID: 8240918
Filing Date: 2012-08-14
Classification: B23P,F16C,F16D,Y10T

Abstract:
1. A shaft member for a fluid dynamic bearing device, comprising: a shaft portion; and a flange portion fixed to one end of the shaft portion, in which: an outer periphery of the shaft portion is provided with a radial bearing surface capable of forming a radial bearing gap between the radial bearing surface and a surface opposed to the radial bearing surface; and one end surface of the flange portion is provided with a thrust bearing surface capable of forming a thrust bearing gap between the thrust bearing surface and a surface opposed to the thrust bearing surface, the shaft member being rotated and supported by fluid film formed in the radial bearing gap and the thrust bearing gap, wherein: a radially inner side of the one end surface with respect to the thrust bearing surface is provided with a relief portion having a flat surface closer to an another end surface of the flange portion than the thrust bearing surface, the shaft portion is press-fitted into a hole portion provided in the flange portion; and the relief portion of the flange portion is partially subjected to a caulking process as plastic working, a caulked portion with respect to the shaft portion is constituted by a first hump portion generated on a radially inner side of a portion recessed by the caulking process in the relief portion and the flange portion is fixed to the shaft portion by the caulked portion.