Shaft Member for Fluid Lubrication Bearing Apparatuses and a Method for Producing the Same

摘要

A shaft member for hydrodynamic bearing apparatuses which can restore the pressure balance in a thrust bearing gap formed on both axial sides of the flange portion in an early stage is provided at low costs. A shaft material 10 integrally having a shaft portion 11 and a flange portion 12 is formed as a through-hole 19 opening to its both end faces 12a, 12b on the flange portion 12 of the shaft material 10 is formed in a common forging step. As a result, the through-hole 29 is formed to open to the inner diameter side of these bearing gap W1, W2 avoiding thrust bearing gaps W1, W2 formed on both end faces of the flange portion 22 of the shaft member 2 as a finished product.