HOLLOW DRIVE SHAFT AND METHOD FOR MANUFACTURING SAME

The present invention has been made in an effort to provide a hollow drive shaft and a method for manufacturing the same in which the concentrated load to a weak point which may be occurred by differences of sectional thicknesses and outer diameters is dispersed so that the strength may be uniform throughout the whole length. A hollow drive shaft includes: one or more small-diameter portion having a hollow shape; and a large-diameter portion which is disposed in the vicinity of the small-diameter portion and has an outer diameter relatively greater than the small-diameter portion. A sectional thickness of the large-diameter portion is less than a sectional thickness of the small-diameter portion, and a first sectional portion from an outer surface to a point corresponding to 35% to 60% of a sectional thickness of the large-diameter portion is carburized to have a first hardness.