JOINT STRUCTURE OF SHAFT MEMBER

摘要

PROBLEM TO BE SOLVED: To prevent reduction in joint strength of friction welding between an output shaft formed with serrations on an internal peripheral surface thereof and a yoke of the output shaft. SOLUTION: There is provided the joint structure of a shaft member in which one end portion 13a of a cylindrical output shaft 13 having a hallow inside and a flat base end portion 20 of the yoke 14 of the output shaft are joined by friction welding. The output shaft is formed with serrations 19 on the internal peripheral surface thereof and with annular unformed portions 25 by applying counter sinking process to the serrations 19 on an internal peripheral surface of the one end portion at a side to be welded. Thereby, circumferential thickness of curls 28 generated at the time of welding between the one end portion of the output shaft and an external surface of the base portion 20 on the yoke of the output shaft is formed equally, so that reduction in the joint strength is prevented.