| 摘要 |
PROBLEM TO BE SOLVED: To make a steering shaft lightweight and reduce its cost by forming a large-diameter section expanded in diameter by expansion machining at the prescribed position of a hollow material, and forming a bottomed recess coupled with a lock member on the outer peripheral face side of the large-diameter section. SOLUTION: The rotation of a steering shaft 1 is restricted by its coupling with a lock member, and the steering shaft 1 is formed with a steel hollow material 10. A small-diameter section 20 shrunk with the hollow material 10 in diameter is formed at one end section, and a large-diameter section 30 expanded with the hollow material 10 in diameter is formed at the prescribed position near the small-diameter section 20. A bottomed recess 40 penetrates between the erected faces 32 of the large-diameter section 30 erected from the outer periphery 11 of the hollow material 10 and gradually expanded in diameter toward the outer periphery 31 of the large-diameter section 30 along the axis of the hollow material 10. The steering shaft 1 can be made lightweight. |
