Patent ID: 8931175
Filing Date: 2015-01-13
Classification: F16C,Y10T

Abstract:
1. A method of manufacturing a bearing member including a mold portion and an electroforming portion having a dynamic pressure generating portion on an inner circumferential surface thereof and disposed on an inner circumferential surface of the mold portion, comprising the steps of: fabricating a master shaft having a forming portion corresponding to a shape of the dynamic pressure generating portion on an outer circumference of the master shaft, the forming portion having an irregular shape in an axial direction; forming the electroforming portion by depositing a metal on the outer circumference of the forming portion of the master shaft by immersing the forming portion corresponding to the shape of the dynamic pressure generating portion of the master shaft into an electrolytic solution containing metal ions; inserting the electroforming portion with the master shaft into a mold after the electroforming portion is formed; forming the mold portion of the bearing member by infection molding material around the electroforming portion; and separating the master shaft and the electroforming portion from each other after the injection molding, such that a gap is formed between the forming portion of the master shaft and the dynamic pressure generating portion of the electroforming portion, the gap being formed by a diameter expansion of the inner circumferential surface of the electroforming portion, and the gap having a size that can cancel axial engagement of irregularities between the dynamic pressure generating portion and the forming portion when drawing the master shaft out from the electroforming portion.