Shaft with spline and stress relief groove and manufacturing method thereof

摘要

The shaft has a shank (10) with a splined portion (14) spline engaged with an inward joint part (2) and with an external diameter portion (11) formed with a distance of separation from the splined portion. Multiple curved portions and a straight portion extends continuously to connect a cut back portion formed at an end portion of a groove portion (14a) of the splined and diameter portions. An independent claim is also included for a manufacturing method for manufacturing a shaft.