Abstract: In a dynamic pressure bearing device which has a shaft (3), a bearing (10) rotatable relative to the shaft (3), and capillary seal portions (13, 14) for holding a lubricating fluid (15) in a bearing clearance and in which the shaft (3) and the bearing (10) are relatively rotatably supported by dynamic pressure of the lubricating fluid (15) in the bearing clearance is scattered by centrifugal force so that the lubricating fluid (15) is kept in a constant quantity by the capillary seal portions (13, 14).

Abstract: A potential-difference alleviating member for alleviating and lowering the potential difference, which is an energy difference between a rotating or fixed bearing member and a rotary hub or a fixing frame which are formed of metals of different types, is interposed between the two members so as to prevent the occurrence or advance of potential difference corrosion. Relief portions are respectively provided at a joining interface between a rotary shaft and a thrust plate and a joining interface between a bearing member and the counter plate, and the respective members are welded in the relief portions so as to be integrated.

Abstract: A potential-difference alleviating member for alleviating and lowering the potential difference, which is an energy difference between a rotating or fixed bearing member and a rotary hub or a fixing frame which are formed of metals of different types, is interposed between the two members so as to prevent the occurrence or advance of potential difference corrosion. Relief portions are respectively provided at a joining interface between a rotary shaft and a thrust plate and a joining interface between a bearing member and the counter plate, and the respective members are welded in the relief portions so as to be integrated.

Abstract: A potential-difference alleviating member for alleviating and lowering the potential difference, which is an energy difference between a rotating or fixed bearing member and a rotary hub or a fixing frame which are formed of metals of different types, is interposed between the two members so as to prevent the occurrence or advance of potential difference corrosion. Relief portions are respectively provided at a joining interface between a rotary shaft and a thrust plate and a joining interface between a bearing member and the counter plate, and the respective members are welded in the relief portions so as to be integrated.

Abstract: A shaft member 21 the flexible, austenitic stainless steel is cold worked, and in the cold working process, a cold working ratio is increased, whereby a surface of the shaft member 21 is hardened. Therefore, there is no need for a nitriding treatment for the surface hardening. The corrosion proof performance of the passive coating possessed by the stainless steel is kept as intact.