HYDRODYNAMIC BEARING AND ITS MANUFACTURING METHOD, DEVICE FOR MANUFACTURING SHAFT MEMBER FOR HYDRODYNAMIC BEARING, SPINDLE MOTOR, AND RECORDING DISC DRIVING APPARATUS

摘要

PROBLEM TO BE SOLVED: To allow highly precise joint between a shaft and a thrust plate constituting a hydrodynamic bearing by using a simple method.

SOLUTION: A circumferential protrusion and an annular groove having a diameter smaller than the shaft are provided on the joint surface of one of the shaft and the thrust plate. Both members are joined together in mutual line contact with resistance welding to form a region to be welded to these joint surfaces and a region not to be welded thereto. Thus, the thrust plate has highly precise perpendicularity to the shaft. During joint between the shaft and the thrust plate, the thrust plate is held by a resin aligning tool and then its center is positioned. Thereby, it has good coaxiality with the shaft while eliminating the influences of a machining tolerance.

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