A method of fabricating a power transmission shaft

摘要

A power transmission shaft such as a spline shaft and a serration shaft is provided which has improved static strength and fatigue strength. In a power transmission shaft, a diameter expansion surface (22) is formed in a valley section (21a) of a tooth (21) on the opposite side of a shaft end. First blunt sections in the shape of a curved surface are formed in comers (C1) between the diameter expansion surface (22) and a tooth surface (21c) adjacent to the diameter expansion surface (22), in order to blunt edges. <IMAGE>